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Millicell ULA 96孔U型底清单膠纸板说明书

User GuideMillicell® Ultra-low Attachment Plates96-well, U-bottom, clear polystyreneMC96ULA20Product DescriptionThe Millicell® Ultra-low Attachment (ULA), 96-well,U-bottom, clear plates are used to generate homogeneous spheroid cultures.Each well contains a specialized ULA ultra-hydrophilic polymer coating that enables spontaneous spheroid formation of uniform size and shape, and prevents cells from adhering. Coupled with the U-shaped round bottom, the Millicell® ULA Plates enable the production, culture, and analysis of spheroids and other 3D cell structures. The initial cell aggregate size is highly uniform and can be controlled by adjusting the initial cell seeding. The clear Millicell® ULA Plates offer great visibility of aggregate formation and growth of the 3D cultures over time.Millicell® ULA Plates promote scaffold free,self-assembly of spheroid formation. The Millicell®ULA Plates have high optical clarity making them highly suitable for brightfield imaging and confocal microscopy.Millicell® ULA Plates are gamma irradiated in packaging. Features• Millicell® ULA Plates have well numbers indicated on both top and bottom of each column.• The frosted effect on the plate enhances the ability to read the column and row indication labels.• The plate has an opening on the on the long sideof the bottom of the plate for easier grip.• The Millicell® ULA Plate lid fits the plate with rings designed to frame the top of each well to impede evaporation.• The round U-shaped bottom of the Millicell® ULA Plate provides optimum spheroid growth.• Stable, non-cytotoxic and cell non-adhesionsurface• Easy to handle, compatible with liquid roboticsystem• Round bottom wells have high optical claritymaking them suitable for bright field imagingand confocal microscopy.• Uniform single spheroid formation in each well 3D Spheroid Applications• Fluorescent Image Analysis, cell divisionin spheroids• Fluorescent Image Analysis, live dead cellassay of spheroids• Evaluations of Drug Efficacy, the responseof co-cultured spheroids to drugs• Analysis of Anticancer Drugs, targetingthe interior of spheroid• Evaluation of Drug Efficacy, quantitative evaluation of spheroid size• Evaluation of Drug Efficacy, the responseof spheroids to a drug• Cell Counting, measuring the numberof cells in spheroidsStorageStore Millicell® ULA Plates at room temperature and low humid location away from direct sunlight. Do not use if package is wet or damaged.Chemical Resistance0.1%SpecificationsPlate Type 96-wellPlate Material Clear polystyrene Lid Material Clear polystyrene Well VolumeMax 300 μL <250 μLrecommendedWell Depth10 mm Well Diameter Top/Bottom 7.0/6.1mm Plate Length 127.5 mm Plate Width 85.9 mm Plate Height 14 mm A1 Row Offset 11.45 mm A1 Column Offset14.25 mmWell Center to Well Center Spacing9 mm Flange or Skirt Height 3.5 mm Stack Height12.9 mmWell Bottom Elevation 4 mm Well Bottom Thickness 1.1 mm Distance to Bottom of Plate2.9 mmCompatible with brightfield and fluorescenceimaging systems.Directions for UsePlease read the entire protocol before proceeding.PreparationMillicell® ULA Plates with ULA coating on the well surface, received gamma irradiated in its packaging. To prevent contamination, plates should be opened inside a bio-safety cabinet.Generation of Cell Aggregates from a Single Cell SuspensionMultiple cell lines were shown to form single, centered spheroids in 96-well microplate formats. Brightfield images were taken after incubating samples for 72 hours (10x and 4x magnification).A549HeLa HepG2MCF7Cells grow and divide to formspheroids within 24-72 hoursBrightfield images of spheroidsSeeding Cells in wells1. Culture cells in 2D cell culture flask until they are between 60-80% confluence.2. Aspirate media from the culture flask.3. Add sterile PBS for 3 minutes at room temperature.4. Aspirate liquid from the culture flask.5. Add Trypsin to the culture flask and incubate at 37 °C 5% carbon dioxide cell culture incubator.6. Stop the trypsin reaction by adding equal parts complete cell culture media to the flask.7. Collect liquid suspension and spin down in the centrifuge at 300 x g for 3 minutes.8. Re-suspend cells in 1 mL of cell complete culture media.9. Count cells using Trypan Blue Solution and a Millicell® Disposable Hemocytometer. Mix 90% trypan bluewith 10% cell suspension (e.g., 180 µL trypan blue and 20 µL cell suspension).10. Count live cells on the hemocytometer and calculate cells per milliliter.11. Mix to create a single cell suspension and add desired cell suspension amount to 96-well microplate.Note: Millicell® ULA Plates can hold a maximum of 300 µL volume, but we advise <250 µL volume for best results.12. Depending on the cell type and medium, cells will aggregate to form a single spheroid within24-72 hours (about 3 days).How to Change MediumFor best results perform half media changes to avoid disrupting spheroid formation (if total well volume is 200 µL, then aspirate 100 µL and replace with fresh 100 µL volume).Millicell®Uniform spheroidformation resultsImaging and Staining SpheroidsSpheroids may be generated, cultured, and assayed for fluorescent or luminescent signals in the same Millicell® ULA Plate without the need to transfer them to another plate. The unique U-shaped well geometry makes them suitable for automated imaging of spheroids for high content screening approaches.Images below have been taken on the ImageXpress® Micro Confocal High-Content Imaging Systemwith 10x objective.Nuclear Actin CompositeA549HeLaHepG2MCF7In-well Assay Manipulation for Fixation and Staining Spheroid1. (x3) Remove 100 µL from supernatant and add100 µL wash buffer. Incubate at room temperature for 5 minutes.Note: For best results perform half media changes to avoid disrupting spheroid formation (if total well volume is 200 µL, then aspirate out 100 µL volume and replace with fresh 100 µL volume).2. Remove 100 µL from supernatant. Add in2x fixative (e.g., 8% PFA for a final concentration of 4% PFA) and incubate for 1 hour at 4 °C.Note: The fixative is made up as a 2x stock andadded 1:1 with the residual volume in the wellwith the spheroid.3. (x3) Remove 100 µL from supernatant and add100 µL wash buffer. Incubate at room temperature for 5 minutes.4. Remove 100 µL from supernatant. Add in primaryantibodies and incubate for 1 hour in the dark at room temperature.5. (x3) Remove 100 µL from supernatant and add100 µL wash buffer. Incubate at room temperature for 5 minutes.6. Remove 100 µL from supernatant. Add in secondaryantibodies and incubate for 1 hour in the dark atroom temperature.7. (x3) Remove 100 µL from supernatant and add100 µL wash buffer. Incubate at room temperature for 5 minutes.8. Remove 100 µL from supernatant. Dilute stock DAPIin PBS to 1 µg/µL and add 100 µL to each well.Incubate overnight in the dark at 4 °C.Note: Wrap your plate with paraffin or other sealant to avoid evaporation of liquid.9. (x3) Remove 100 µL from supernatant and add100 µL wash buffer. Incubate at room temperature for 5 minutes.10. Ready to image.TroubleshootingProblem Cause(s)Solution(s)Single cell suspensionaggregating/clumping Sticky/clumpy cells Use a 40 µm cell strainer to remove aggregates/clumps of cellsSpheroids not forming or multiple aggregates formed Pipette touched the bottom orsides of the microwell whenmanually seedingReseed plate avoiding contact with the platebottom or sidesULA coating damaged Replace the platePre-existing aggregates in well Start with a single cell suspensionMore time is requiredCells may take 24-72 hours depending ontype. Optimization is required for eachcell typeBacterial contamination Check culture for bacteria and use antibioticsin mediaSpheroids formingloose aggregates Cell lines may vary Fibroblast co-culture may be required Additional media supplementation such asmethyl-cellulose may be required Optimization is normally required for each cell typeLosing spheroids during media changes This is an ultra-low attachmentplate, non-adhesion spheroidsmight be inadvertently removedwith media aspiration.Perform half media changes andmicro-pipette gentlySlowly aspirate liquid so not to disturb3D culturesDo not set the pipette tip near the spheroidin the mediaSpheroids are not forming uniform size 3D aggregates Non-uniform starting single cellsuspensionEnsure that you are mixing the starting singlecell suspension before adding it to plate Heterogeneous co-culture cellmixtureMix co-culture cell types well beforedispensing into the plateUnknown starting quantity of cells Count cells in a hemocytometer to add aknown cell number to the plateUnequal media volume Add equivalent volumes of media to each wellThe life science business of Merck operates as MilliporeSigma in the U.S. and Canada.Merck, Millipore, Product Name, and Sigma-Aldrich are trademarks of Merck KGaA, Darmstadt, Germany or its affiliates. All other trademarks are the property of their respective owners. Detailed information on trademarks is available via publicly accessible resources.© 2023 Merck KGaA, Darmstadt, Germany and/or its affiliates. All Rights Reserved.Document Template 00035533 Ver 1.0Product OrderingTo order , go to .DescriptionQuantity Catalogue Number Millicell Ultra-low Attachment Plates,96-well, U-bottom, Clear 20 pkMC96ULA20Trypan Blue Solution 50 mL 93595-50ML Trypsin100 mg T2600000Millicell ® Disposable Hemocytometer50 pkMDH-2N1-50PKNoticeWe provide information and advice to our customers on application technologies and regulatory matters to the best of our knowledge and ability, but without obligation or liability. Existing laws and regulations are to be observed in all cases by our customers. This also applies in respect to any rights of third parties. Our information and advice do not relieve our customers of their own responsibility for checking the suitability of our products for the envisaged purpose.The information in this document is subject to change without notice and should not be construed as acommitment by the manufacturing or selling entity, or an affiliate. We assume no responsibility for any errors that may appear in this document.Technical AssistanceVisit the tech service page on our web site at /TechService .Terms and Conditions of SaleWarranty, use restrictions, and other conditions of sale may be found at /Terms .Contact InformationFor the location of the office nearest you, go to /Offices .。

人工智能AI革命外文翻译中英文

人工智能（AI）革命外文翻译中英文英文The forthcoming Artificial Intelligence (AI) revolution:Its impact on society and firmsSpyros MakridakisAbstractThe impact of the industrial and digital (information) revolutions has, undoubtedly, been substantial on practically all aspects of our society, life, firms and employment. Will the forthcoming AI revolution produce similar, far-reaching effects? By examining analogous inventions of the industrial, digital and AI revolutions, this article claims that the latter is on target and that it would bring extensive changes that will also affect all aspects of our society and life. In addition, its impact on firms and employment will be considerable, resulting in richly interconnected organizations with decision making based on th e analysis and exploitation of “big” data and intensified, global competition among firms. People will be capable of buying goods and obtaining services from anywhere in the world using the Internet, and exploiting the unlimited, additional benefits that will open through the widespread usage of AI inventions. The paper concludes that significant competitive advantages will continue to accrue to those utilizing the Internet widely and willing to take entrepreneurial risks in order to turn innovative products/services into worldwide commercial success stories. The greatest challenge facing societies and firms would be utilizing the benefits of availing AI technologies, providing vast opportunities for both new products/services and immense productivity improvements while avoiding the dangers and disadvantages in terms of increased unemployment and greater wealth inequalities.Keywords：Artificial Intelligence (AI)，Industrial revolution，Digital revolution，AI revolution，Impact of AI revolution，Benefits and dangers of AI technologies The rise of powerful AI will be either the best or the worst thing ever to happento humanity. We do not yet know which.Stephen HawkingOver the past decade, numerous predictions have been made about the forthcoming Artificial Intelligence (AI) Revolution and its impact on all aspects of our society, firms and life in general. This paper considers such predictions and compares them to those of the industrial and digital ones. A similar paper was written by this author and published in this journal in 1995, envisioning the forthcoming changes being brought by the digital (information) revolution, developing steadily at that time, and predicting its impact for the year 2015 (Makridakis, 1995). The current paper evaluates these 1995 predictions and their impact identifying hits and misses with the purpose of focusing on the new ones being brought by the AI revolution. It must be emphasized that the stakes of correctly predicting the impact of the AI revolution arefar reaching as intelligent machines may become our “final invention” that may end human supremacy (Barrat, 2013). There is little doubt that AI holds enormous potential as computers and robots will probably achieve, or come close to, human intelligence over the next twenty years becoming a serious competitor to all the jobs currently performed by humans and for the first time raising doubt over the end of human supremacy.This paper is organized into four parts. It first overviews the predictions made in the 1995 paper for the year 2015, identifying successes and failures and concluding that major technological developments (notably the Internet and smartphones) were undervalued while the general trend leading up to them was predicted correctly. Second, it investigates existing and forthcoming technological advances in the field of AI and the ability of computers/machines to acquire real intelligence. Moreover, it summarizes prevailing, major views of how AI may revolutionize practically everything and its impact on the future of humanity. The third section sums up the impact of the AI revolution and describes the four major scenarios being advocated, as well as what could be done to avoid the possible negative consequences of AI technologies. The fourth section discusses how firms will be affected by these technologies that will transform the competitive landscape, how start-up firms are founded and the way success can be achieved. Finally, there is a brief concluding section speculating about the future of AI and its impact on our society, life, firms and employment.1. The 1995 paper: hits and missesThe 1995 paper (Makridakis, 1995) was written at a time when the digital (at that time it was called information) revolution was progressing at a steady rate. The paper predicted that by 2015 “the information revolution should be in full swing” and that “computers/communications” would be in widespread use, whi ch has actually happened, although its two most important inventions (the Internet and smartphones) and their significant influence were not foreseen as such. Moreover, the paper predicted that “a single computer (but not a smartphone) can, in addition to its traditional tasks, also become a terminal capable of being used interactively for the following:” (p. 804–805)• Picture phone and teleconference• Television and videos• Music• Shopping• On line banking and financial services• Reservations• Medic al advice• Access to all types of services• Video games• Other games (e.g., gambling, chess etc.)• News, sports and weather reports• Access to data banksThe above have all materialized and can indeed be accessed by computer,although the extent of their utilization was underestimated as smartphones are now being used widely. For instance, the ease of accessing and downloading scientific articles on one's computer in his/her office or home would have seemed like science fiction back in 1995, when finding such articles required spending many hours in the library (often in its basement for older publications) and making photocopies to keep them for later use. Moreover, having access, from one's smartphone or tablet, to news from anywhere in the world, being able to subscribe to digital services, obtain weather forecasts, purchase games, watch movies, make payments using smartphones and a plethora of other, useful applications was greatly underestimated, while the extensive use of the cloud for storing large amounts of data for free was not predicted at all at that time. Even in 1995 when the implications of Moore's law leading to increasing computer speed and storage while reducing costs were well known, nevertheless, it was hard to imagine that in 2016 there would be 60 trillion web pages, 2.5 billion smartphones, more than 2 billion personal computers and 3.5 billion Google searches a day.The paper correctly predicted “as wireless telecommunications will be possible the above list of capabilities can be accessed from anywhere in the world without the need for regular telephone lines”. What the 1995 paper missed, however, was that in 2015 top smartphones, costing less than €500, would be as powerful as the 1995 supercomputer, allowing access to the Internet and all tasks that were only performed by expensive computers at that time, including an almost unlimited availability of new, powerful apps providing a large array of innovative services that were not imagined twenty years ago. Furthermore, the paper correctly predicted super automation leading to unattended factories stating that “by 2015 there will be little need for people to do repetitive manual or mental tasks”. It also foresaw the decline of large industrial firms, increased global competition and the drop in the percentage of labour force employed in agriculture and manufacturing (more on these predictions in the section The Impact of the AI Revolution on Firms). It missed however the widespread utilization of the Internet (at that time it was a text only service), as well as search engines (notably Google), social networking sites(notably Facebook) and the fundamental changes being brought by the widespread use of Apple's iPhone, Samsung's Galaxy and Google's Android smartphones. It is indeed surprising today to see groups of people in a coffee shop or restaurant using their smartphones instead of speaking to each other and young children as little as three or four years of age playing with phones and tablets. Smartphones and tablets connected to the Internet through Wi-Fi have influenced social interactions to a significant extent, as well as the way we search for information, use maps and GPS for finding locations, and make payments. These technologies were not predicted in the 1995 paper.2. Towards the AI revolutionThe 1995 paper referred to Say, the famous French economist, who wrote in 1828 about the possibility of cars as substitutes for horses:“Nevertheless no machine will ever be able to perform what even the worst horses can - the service of carrying people and goods through the bustle and throng of a great city.” (p. 800)Say could never have dreamed of, in his wildest imagination, self-driving cars, pilotless airplanes, Skype calls, super computers, smartphones or intelligent robots. Technologies that seemed like pure science fiction less than 190 years ago are available today and some like self-driving vehicles will in all likelihood be in widespread use within the next twenty years. The challenge is to realistically predict forthcoming AI technologies without falling into the same short-sighted trap of Say and others, including my 1995 paper, unable to realize the momentous, non-linear advancements of new technologies. There are two observations to be made.First, 190 years is a brief period by historical standards and during this period we went from horses being the major source of transportation to self-driving cars and from the abacus and slide rules to powerful computers in our pockets. Secondly, the length of time between technological inventions and their practical, widespread use is constantly being reduced. For instance, it took more than 200 years from the time Newcomen developed the first workable steam engine in 1707 to when Henry Ford built a reliable and affordable car in 1908. It took more than 90 years between the time electricity was introduced and its extensive use by firms to substantially improve factory productivity. It took twenty years, however, between ENIAC, the first computer, and IBM's 360 system that was mass produced and was affordable by smaller business firms while it took only ten years between 1973 when Dr Martin Cooper made the first mobile call from a handheld device and its public launch by Motorola. The biggest and most rapid progress, however, took place with smartphones which first appeared in 2002 and saw a stellar growth with the release of new versions possessing substantial improvements every one or two years by the likes of Apple, Samsung and several Chinese firms. Smartphones, in addition to their technical features, now incorporate artificial intelligence characteristics that include understanding speech, providing customized advice in spoken language, completing words when writing a text and several other functions requiring embedded AI, provided by a pocket computer smaller in size than a pack of cigarettes.From smart machines to clever computers and to Artificial Intelligence (AI) programs: A thermostat is a simple mechanical device exhibiting some primitive but extremely valuable type of intelligence by keeping temperatures constant at some desired, pre-set level. Computers are also clever as they can be instructed to make extremely complicated decisions taking into account a large number of factors and selection criteria, but like thermostats such decisions are pre-programmed and based on logic, if-then rules and decision trees that produce the exact same results, as long as the input instructions are alike. The major advantage of computers is their lightning speed that allows them to perform billions of instructions per second. AI, on the other hand, goes a step further by not simply applying pre-programmed decisions, but instead exhibiting some learning capabilities.The story of the Watson computer beating Jeopardy's two most successful contestants is more complicated, since retrieving the most appropriate answer out of the 200 million pages of information stored in its memory is not a sign of real intelligence as it relied on its lightning speed to retrieve information in seconds. What is more challenging according to Jennings, one of Jeopardy's previous champions, is“to read clues in a natural language, understand puns and the red herrings, to unpack just the meaning of the clue” (May, 2013). Similarly, it is a sign of intelligence to improve it s performance by “playing 100 games against past winners”. (Best, 2016). Watson went several steps beyond Deep Blue towards AI by being able to understand spoken English and learn from his mistakes (New Yorker, 2016). However, he was still short of AlphaGo that defeated Go Champions in a game that cannot be won simply by using “brute force” as the number of moves in this game is infinite, requiring the program to use learning algorithms that can improve its performance as it plays more and more gamesComputers and real learning: According to its proponents, “the main focus of AI research is in teaching computers to think for themselves and improvise solutions to common problems” (Clark, 2015). But many doubt that computers can learn to think for themselves even though they can display signs of intelligence. David Silver, an AI scientist working at DeepMind, explained that “even though AlphaGo has affectively rediscovered the most subtle concepts of Go, its knowledge is implicit. The computer parse out these concepts –they simply emerge from its statistical comparisons of types of winning board positions at GO” (Chouard, 2016). At the same time Cho Hyeyeon, one of the strongest Go players in Korea commented that “AlphaGo seems like it knows everything!” while others believe that “AlphaGo is likely to start a ‘new revolution’ in the way we play Go”as “it is seeking simply to maximize its probability of reaching winning positions, rather than as human players tend to do –maximize territorial gains” (Chouard, 2016). Does it matter, as Silver said, that AlphaGo's knowledge of the game is implicit as long as it can beat the best players? A more serious issue is whether or not AlphaGo's ability to win games with fixed rules can extend to real life settings where not only the rules are not fixed, but they can change with time, or from one situation to another.From digital computers to AI tools: The Intel Pentium microprocessor, introduced in 1993, incorporated graphics and music capabilities and opened computers up to a large number of affordable applications extending beyond just data processing. Such technologies signalled the beginning of a new era that now includes intelligent personal assistants understanding and answering natural languages, robots able to see and perform an array of intelligent functions, self-driving vehicles and a host of other capabilities which were until then an exclusive human ability. The tech optimists ascertain that in less than 25 years computers went from just manipulating 0 and 1 digits, to utilizing sophisticated neural networkalgorithms that enable vision and the understanding and speaking of natural languages among others. Technology optimists therefore maintain there is little doubt that in the next twenty years, accelerated AI technological progress will lead to a breakthrough, based on deep learning that imitates the way young children learn, rather than the laborious instructions by tailor-made programs aimed for specific applications and based on logic, if-then rules and decision trees (Parloff, 2016).For instance, DeepMind is based on a neural program utilizing deep learning that teaches itself how to play dozens of Atari games, such as Breakout, as well or better than humans, without specific instructions for doing so, but by playing thousands ofgames and improving itself each time. This program, trained in a different way, became the AlphaGo that defeated GO champion Lee Sodol in 2016. Moreover, it will form the core of a new project to learn to play Starcraft, a complicated game based on both long term strategy as well as quick tactical decisions to stay ahead of an opponent, which DeepMind plans to be its next target for advancing deep learning (Kahn, 2016). Deep learning is an area that seems to be at the forefront of research and funding efforts to improve AI, as its successes have sparked a burst of activity in equity funding that reached an all-time high of more than $1 billion with 121 projects for start-ups in the second quarter of 2016, compared to 21 in the equivalent quarter of 2011 (Parloff, 2016).Google had two deep learning projects underway in 2012. Today it is pursuing more than 1000, according to their spokesperson, in all its major product sectors, including search, Android, Gmail, translation, maps, YouTube, and self-driving cars (The Week, 2016). IBM's Watson system used AI, but not deep learning, when it beat the two Jeopardy champions in 2011. Now though, almost all of Watson's 30 component services have been augmented by deep learning. Venture capitalists, who did not even know what deep learning was five years ago, today are wary of start-ups that do not incorporate it into their programs. We are now living in an age when it has become mandatory for people building sophisticated software applications to avoid click through menus by incorporating natural-language processing tapping deep learning (Parloff, 2016).How far can deep learning go? There are no limits according to technology optimists for three reasons. First as progress is available to practically everyone to utilize through Open Source software, researchers will concentrate their efforts on new, more powerful algorithms leading to cumulative learning. Secondly, deep learning algorithms will be capable of remembering what they have learned and apply it in similar, but different situations (Kirkpatrick et al., 2017). Lastly and equally important, in the future intelligent computer programs will be capable of writing new programs themselves, initially perhaps not so sophisticated ones, but improving with time as learning will be incorporated to be part of their abilities. Kurzweil (2005) sees nonbiological intelligence to match the range and subtlety of human intelligence within a quarter of a century and what he calls “Singularity” to occur by 2045, b ringing “the dawning of a new civilization that will enable us to transcend our biological limitations and amplify our creativity. In this new world, there will be no clear distinction between human and machine, real reality and virtual reality”.For some people these predictions are startling, with far-reaching implications should they come true. In the next section, four scenarios associated with the AI revolution are presented and their impact on our societies, life work and firms is discussed.3. The four AI scenariosUntil rather recently, famines, wars and pandemics were common, affecting sizable segments of the population, causing misery and devastation as well as a large number of deaths. The industrial revolution considerably increased the standards of living while the digital one maintained such rise and also shifted employment patterns,resulting in more interesting and comfortable office jobs. The AI revolution is promising even greater improvements in productivity and further expansion in wealth. Today more and more people, at least in developed countries, die from overeating rather than famine, commit suicide instead of being killed by soldiers, terrorists and criminals combined and die from old age rather than infectious disease (Harari, 2016). Table 1 shows the power of each revolution with the industrial one aiming at routine manual tasks, the digital doing so to routine mental ones and AI aiming at substituting, supplementing and/or amplifying practically all tasks performed by humans. The cri tical question is: “what will the role of humans be at a time when computers and robots could perform as well or better andmuch cheaper, practically all tasks that humans do at present?” There are four scenarios attempting to answer this question.The Optimists: Kurzweil and other optimists predict a “science fiction”, utopian future with Genetics, Nanotechnology and Robotics (GNR) revolutionizing everything, allowing humans to harness the speed, memory capacities and knowledge sharing ability of computers and our brain being directly connected to the cloud. Genetics would enable changing our genes to avoid disease and slow down, or even reverse ageing, thus extending our life span considerably and perhaps eventually achieving immortality. Nanotechnology, using 3D printers, would enable us to create virtually any physical product from information and inexpensive materials bringing an unlimited creation of wealth. Finally, robots would be doing all the actual work, leaving humans with the choice of spending their time performing activities of their choice and working, when they want, at jobs that interest them.The Pessimists: In a much quoted article from Wired magazine in 2000, Bill Joy (Joy, 2000) wrote “Our most powerful 21st-century technologies –robotics, genetic engineering, and nanotech –are threatening to make humans an endangered species”. Joy pointed out that as machines become more and more intelligent and as societal problems become more and more complex, people will let machines make all the important decisions for them as these decisions will bring better results than those made by humans. This situation will, eventually, result in machines being in effective control of all important decisions with people dependent on them and afraid to make their own choices. Joy and many other scientists (Cellan-Jones, 2014) and philosophers (Bostrom, 2014) believe that Kurzweil and his supporters vastly underestimate the magnitude of the challenge and the potential dangers which can arise from thinking machines and intelligent robots. They point out that in the utopian world of abundance, where all work will be done by machines and robots, humans may be reduced to second rate status (some saying the equivalent of computer pets) as smarter than them computers and robots will be available in large numbers and people will not be motivated to work, leaving computers/robots to be in charge of making all important decisions. It may not be a bad world, but it will definitely be a different one with people delegated to second rate status.Harari is the newest arrival to the ranks of pessimists. His recent book (Harari, 2016, p. 397) concludes with the following three statements:• “Science is converging to an all-encompassing dogma, which says thatorganisms are algorithm s, and life is data processing”• “Intelligence is decoupling from consciousness”• “Non-conscious but highly intelligent algorithms may soon know us better than we know ourselves”Consequently, he asks three key questions (which are actually answered by the above three statements) with terrifying implications for the future of humanity: • “Are organisms really just algorithms, and is life just data processing?”• “What is more valuable –intelligence or consciousness?”• “What will happen to society, polit ics and daily life when non-conscious but highly intelligent algorithms know us better than we know ourselves?”Harari admits that nobody really knows how technology will evolve or what its impact will be. Instead he discusses the implications of each of his three questions: • If indeed organisms are algorithms then thinking machines utilizing more efficient ones than those by humans will have an advantage. Moreover, if life is just data processing then there is no way to compete with computers that can consult/exploit practically all available information to base their decisions.• The non-conscious algorithms Google search is based on the consultation of millions of possible entries and often surprise us by their correct recommendations. The implications that similar, more advanced algorithms than those utilized by Google search will be developed (bearing in mind Google search is less than twenty years old) in the future and be able to access all available information from complete data bases are far reachi ng and will “provide us with better information than we could expect to find ourselves”.• Humans are proud of their consciousness, but does it matter that self-driving vehicles do not have one, but still make better decisions than human drivers, as can be confirmed by their significantly lower number of traffic accidents?When AI technologies are further advanced and self-driving vehicles are in widespread use, there may come a time that legislation may be passed forbidding or restricting human driving, even though that may still be some time away according to some scientists (Gomes, 2014). Clearly, self-driving vehicles do not exceed speed limits, do not drive under the influence of alcohol or drugs, do not get tired, do not get distracted by talking on the phone or sending SMS or emails and in general make fewer mistakes than human drivers, causing fewer accidents. There are two implications if humans are not allowed to drive. First, there will be a huge labour displacement for the 3.5 million unionized truck drivers in the USA and the 600 thousand ones in the UK (plus the additional number of non-unionized ones) as well as the more than one million taxi and Uber drivers in these two countries. Second, and more importantly, it will take away our freedom of driving, admitting that computers are superior to us. Once such an admission is accepted there will be no limits to letting computers also make a great number of other decisions, like being in charge of nuclear plants, setting public policies or deciding on optimal economic strategies as their biggest advantage is their objectivity and their ability to make fewer mistakes than humans.One can go as far as suggesting letting computers choose Presidents/PrimeMinisters and elected officials using objective criteria rather than having people voting emotionally and believing the unrealistic promises that candidates make. Although such a suggestion will never be accepted, at least not in the near future, it has its merits since people often choose the wrong candidate and later regret their choice after finding out that pre-election promises were not only broken, but they were even reversed. Critics say if computers do eventually become in charge of making all important decisions there will be little left for people to do as they will be demoted to simply observing the decisions made by computers, the same way as being a passenger in a car driven by a computer, not allowed to take control out of the fear of causing an accident. As mentioned before, this could lead to humans eventually becoming computers’ pets.The pragmatists: At present the vast majority of views about the future implications of AI are negative, concerned with its potential dystopian consequences (Elon Musk, the CEO of Tesla, says it is like “summoning the demon” and calls the consequences worse than what nuclear weapons can do). There are fewer optimists and only a couple of pragmatists like Sam Altman and Michio Kaku (Peckham, 2016) who believe that AI technologies can be controlled through “OpenAI” and effective regulation. The ranks of pragmatists also includes John Markoff (Markoff, 2016) who pointed out that the AI field can be distinguished by two categories: The first trying to duplicate human intelligence and the second to augment it by expanding human abilities exploiting the power of computers in order to augment human decision making. Pragmatists mention chess playing where the present world champion is neither a human nor a computer but rather humans using laptop computers (Baraniuk, 2015). Their view is that we could learn to exploit the power of computers to augment our own skills and always stay a step ahead of AI, or at least not be at a disadvantage. The pragmatists also believe that in the worst of cases a chip can be placed in all thinking machines/robots to render them inoperative in case of any danger. By concentrating research efforts on intelligence augmentation, they claim we can avoid or minimize the possible danger of AI while providing the means to stay ahead in the race against thinking machines and smart robots.The doubters: The doubters do not believe that AI is possible and that it will ever become a threat to humanity. Dreyfus (1972), its major proponent, argues that human intelligence and expertise cannot be replicated and captured in formal rules. He believes that AI is a fad promoted by the computer industry. He points out to the many predictions that did not materialize such as those made by Herbert A. Simon in 1958 that “a computer would be the world's chess champion within ten years” and those made in 1965 that “machines will be capable within twenty years, of doing any work a man can do” (Crevier, 1993). Dreyfus claims that Simon's optimism was totally unwarranted as they were based on false assumptions that human intelligence is based on an information processing viewpoint as our mind is nothing like a computer. Although, the doubters’ criticisms may have been valid in the last century, they cannot stand for the new developments in AI. Deep Blue became the world's chess champion in 1997 (missing Simon's forecast by twenty one years) while we are not far today from machines being capable of doing all the work that humans can do (missing。

动物的发明过程作文英语

动物的发明过程作文英语Title: The Evolutionary Marvel: The Creation of Animals。

Introduction:In the vast tapestry of life on Earth, animalsrepresent some of the most diverse and fascinating organisms. From the microscopic tardigrades to the mighty elephants, the animal kingdom is a testament to the incredible creativity of evolution. But how did these wondrous creatures come to be? Let's delve into the captivating journey of the invention of animals.Origins of Life:The story of animal invention begins billions of years ago, in the primordial soup of Earth's early oceans. Inthis ancient milieu, simple organic molecules gradually organized themselves into more complex structures,eventually giving rise to the first single-celled organisms.These early life forms, such as bacteria and archaea, laid the groundwork for the emergence of multicellular life.The Advent of Multicellularity:Around 600 million years ago, a pivotal moment occurred in the history of life: the transition to multicellularity. This evolutionary leap allowed cells to collaborate and specialize, paving the way for the development of more complex organisms. The exact mechanisms behind this transition remain a subject of scientific inquiry, but itis clear that multicellularity provided a platform for the evolution of diverse body plans and lifestyles.The Rise of Animalia:Among the myriad forms of multicellular life, animals emerged as one of the most remarkable success stories. The precise origins of animals are shrouded in mystery, but genetic and fossil evidence suggests that they share a common ancestor with choanoflagellates, single-celled organisms with a striking resemblance to the collar cellsfound in sponges. From this humble beginning, animals embarked on a journey of innovation and diversification.Key Innovations in Animal Evolution:The evolution of animals was characterized by a seriesof key innovations that allowed for adaptation to various ecological niches and lifestyles. These innovations include:1. Symmetry: The development of bilateral symmetry provided animals with a distinct front and back, as well as a head region with sensory organs concentrated forefficient navigation and interaction with the environment.2. Tissues and Organs: The evolution of specialized tissues and organs allowed animals to perform specific functions more efficiently. From digestive systems to nervous systems, these complex structures enabled animalsto pursue diverse dietary strategies and behavioral patterns.3. Body Plans: Animals exhibit a remarkable diversityof body plans, ranging from the streamlined bodies of fishto the segmented forms of insects. These body plans are the result of millions of years of evolutionary experimentation, shaped by natural selection and environmental pressures.4. Reproduction: Animal reproduction strategies vary widely, from simple asexual reproduction to complex mating rituals. The evolution of sexual reproduction introduced genetic diversity and facilitated the rapid adaptation of populations to changing environments.5. Skeletal Systems: Skeletons provide animals with support, protection, and locomotion. From the exoskeletonsof arthropods to the internal skeletons of vertebrates, these structures play a crucial role in shaping animal form and function.Conclusion:The invention of animals stands as one of the most extraordinary chapters in the history of life on Earth. Through the relentless forces of evolution, animals haveevolved an astonishing array of forms, behaviors, and adaptations, allowing them to thrive in virtually every habitat on the planet. As we continue to unravel the mysteries of animal evolution, we gain a deeper appreciation for the intricate web of life that surrounds us. From the tiniest invertebrates to the largest mammals, each species is a testament to the power and beauty of nature's creative process.。

Periodic Table

Periodic tableHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of 1.00794 u (1.007825 u for Hydrogen-1), hydrogen is the lightest and most abundant chemical element, constituting roughly 75 % of the Universe's elemental mass.[5] Stars in the main sequence are mainlycomposed of hydrogen in its plasma state.Naturally occurring elemental hydrogen isrelatively rare on Earth.The most common isotope of hydrogen isprotium (name rarely used, symbol 1H) with asingle proton and no neutrons. In ioniccompounds it can take a negative charge (ananion known as a hydride and written as H−), or as a positively charged species H+. The latter cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds always occur as more complex species. Hydrogen forms compounds with most elements and is present in water and most organic compounds. It plays a particularly important role in acid-base chemistry with many reactions exchanging protons between soluble molecules. As the simplest atom known, the hydrogen atom has been of theoretical use. For example, as the only neutral atom with an analytic solution to the Schrödinger equation, the study of the energetics and bonding of the hydrogen atom played a key role in the development of quantum mechanics.) was first artificially produced in the Hydrogen gas (now known to be H2early 16th century, via the mixing of metals with strong acids. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance,[6] and that it produces water when burned, a property which later gave it its name, which in Greek means"water-former." At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly combustible.diatomic gas with the molecular formula H2Industrial production is mainly from the steam reforming of natural gas, and less often from more energy-intensive hydrogen production methods like the electrolysis of water.[7] Most hydrogen is employed near its production site, with the two largest uses being fossil fuel processing(e.g., hydrocracking) and ammonia production,mostly for the fertilizer market.Hydrogen is a concern in metallurgy as it canembrittle many metals,[8]complicating the design ofpipelines and storage tanksHelium is the chemical element with atomic number 2 and an atomic weightof 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert monatomic gas that heads the noblegas group in the periodic table. Its boiling and melting points are thelowest among the elements and it exists only as a gas except in extreme conditions. Next to hydrogen, it is the second most abundantelement in the universe, and accounts for 24% of the elemental mass ofour galaxy.An unknown yellow spectral line signature in sunlight was first observedfrom a solar eclipse in 1868 by French astronomer Pierre Janssen. Janssenis jointly credited with the discovery of the element with Norman Lockyer,who observed the same eclipse and was the first to propose that the linewas due to a new element which he named helium. In 1903, large reservesof helium were found in the natural gas fields in parts of the UnitedStates, which is by far the largest supplier of the gas.Helium is used in cryogenics (its largest single use, accounting forabout a quarter of production), the cooling of superconducting magnets, particularly the main commercial application in MRI scanners. Helium'sother industrial uses as a pressurizing and purge gas, and a protective atmosphere for arc welding and processes (such as growing crystals tomake silicon wafers), account for half of its use. Economically minoruses, such as lifting gas in balloons and airships are popularly known.[2]As with any gas with differing density from air, inhaling a small volumeof helium temporarily changes the timbre and quality of the human voice.In scientific research, the behavior of two fluid phases of helium-4,helium I and helium II, is important to researchers studying quantum mechanics (in particular the phenomenon of superfluidity) and to thoselooking at the effects that temperatures near absolute zero have on matter (such as superconductivity).Helium is the second lightest element and is the second most abundant in the observable universe, being present in the universe in masses more than 12 times those of all the heavier elements combined. Its abundance is also similar to this in our own Sun and Jupiter. This is due to the very high binding energy (per nucleon) of helium-4 with respect to the next three elements after helium (lithium, beryllium, and boron). This helium-4 binding energy also accounts for itscommonality as a product in both nuclearfusion and radioactive decay. Most helium inthe universe is helium-4, and is believed tohave been formed during the Big Bang. Some newhelium is being created currently as a resultof the nuclear fusion of hydrogen in starsgreater than 0.5 solar masses.On Earth, the lightness of helium has caused its evaporation from the gas and dust cloud from which the planet condensed, and it is thus relatively rare—0.00052% by volume in the atmosphere. What helium is present today has been mostly created by the natural radioactive decay of heavy radioactive elements (thorium and uranium), as the alpha particles that are emitted by such decays consist of helium-4 nuclei. This radiogenic helium is trapped with natural gas in concentrations up to seven percent by volume, from which it is extracted commercially by a low-temperature separation process called fractional distillation.Lithium is a soft, silver-white metal that belongs to the alkali metal group of chemical elements. It is represented by the symbol Li, and it has the atomic number 3. Under standard conditions it is the lightest metal and the least dense solid element. Like all alkali metals, lithium is highly reactive and flammable. For this reason, lithium metal is typically stored in mineral oil. When cut open, lithium exhibits a metallic luster, but contact with moist air corrodes the surface quickly to a dull silvery gray, then black, tarnish. Because of its high reactivity, lithium only appears naturally in the form of compounds. Lithium occurs in a number of pegmatitic minerals, but is also commonlyobtained from brines and clays. On a commercial scale, lithium metal is isolatedelectrolytically from a mixture of lithium chloride and potassium chloride.The nuclei of lithium are not very stable asthe two stable lithium isotopes found innature have among the lowest bindingenergies per nucleon of all stable nuclides.As a result, they can be used in fissionreactions as well as fusion reactions ofnuclear devices. Due to its low stability,lithium is less common in the solar systemthan 25 of the first 32 chemical elementseven though the nuclei are very light in atomic weight.[1]Trace amounts of lithium are present in the oceans and in some organisms, though the element serves no apparent vital biological function in humans. The lithium ion Li+ administered as any of several lithium salts has proved to be useful as a mood stabilizing drug due to neurological effects of the ion in the human body. Lithium and its compounds have several industrial applications, including heat-resistant glass and ceramics, high strength-to-weight alloys used in aircraft, lithium batteries and lithium-ion batteries. Lithium also has important links to nuclear physics. The transmutation of lithium atoms to tritium was the first man-made form of a nuclear fusion reaction, and lithium deuteride serves as a fusion fuel in staged thermonuclear weaponsBeryllium is the chemical element with the symbol Be and atomic number 4.A bivalent element, beryllium is found naturally only combined with other elements in minerals. Notable gemstones which contain beryllium include beryl (aquamarine, emerald) and chrysoberyl. The free element is a steel-gray, strong, lightweight brittle alkaline earth metal. It isprimarily used as a hardening agent in alloys, notably beryllium copper. Structurally, beryllium's very low density (1.85 times that of water), high melting point (1287 °C), hightemperature stability and lowcoefficient of thermal expansion,make it in many ways an idealaerospace material, and it has beenused in rocket nozzles and is asignificant component of plannedspace telescopes. Because of itsrelatively high transparency toX-rays and other ionizing radiationtypes, beryllium also has a number ofuses as filters and windows for radiation and particle physics experiments.Commercial use of beryllium metal presents technical challenges due to the toxicity (especially by inhalation) of beryllium-containing dusts. Beryllium produces a direct corrosive effect to tissue, and can cause a chronic life-threatening allergic disease called berylliosis in susceptible persons.Beryllium is a relatively rare element in both the Earth and the universe. The element is not known to be necessary or useful for either plant or animal life.Boron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid, which occurs abundantly in the evaporite ores borax and ulexite.Remarkably, pure boron is a rare substance, boron tends to form refractory material containing small amounts of carbon or other elements. Several allotropes of boron exist: amorphous boron is a brown powder and crystalline boron is black, extremely hard (about 9.5 on Mohs' scale), and a poor conductor at room temperature. Boron is used as adopant in the semiconductor industry, while boron compounds play specialized roles as structural and refractory materials and reagents for the synthesis of organic compounds, including pharmaceuticals.Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. There are three naturally occurring isotopes, with 12C and 13C being stable, while 14C is radioactive, decaying with a half-life of about 5730 years.[9] Carbon is one of the few elements known since antiquity.[10][11] The name "carbon" comes from Latin languageThere are several allotropes of carbon of which the best known are graphite, diamond, and amorphous carbon.[12]Thephysical properties of carbon varywidely with the allotropic form. Forexample, diamond is highly transparent,while graphite is opaque and black.Diamond is amongthe hardest materialsknown, while graphite is soft enoughto form a streak on paper (hence itsname, from the Greek word "to write"). Diamond has a very low electrical conductivity, while graphite is a very good conductor. Under normal conditions, diamond has the highest thermal conductivity of all known materials. All the allotropic forms are solids under normal conditions but graphite is the most thermodynamically stable.All forms of carbon are highly stable, requiring high temperature to react even with oxygen. The most common oxidation state of carbon in inorganic compounds is +4, while +2 is found in carbon monoxide and other transition metal carbonyl complexes. The largest sources of inorganic carbon are limestones, dolomites and carbon dioxide, but significant quantities occur in organic deposits of coal, peat, oil and methane clathrates. Carbon forms more compounds than any other element, with almost ten million pure organic compounds described to date, which inturn are a tiny fraction of such compounds that are theoretically possible under standard conditions.[13]Carbon is the 15th most abundant element in the Earth's crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. It is present in all known lifeforms, and in the human body carbon is the second most abundant element by mass (about 18.5%) after oxygen.[14] This abundance, together with the unique diversity of organic compounds and their unusual polymer-forming ability at the temperatures commonly encountered on Earth, make this element the chemical basis of all known life.Nitrogen (NYE-tro-jin) is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere.Many industrially important compounds, such as ammonia, nitric acid, organic nitrates (propellants and explosives), and cyanides, contain nitrogen. The extremely strong bond in elemental nitrogen dominates nitrogen chemistry, causing difficulty for both organisms and industryinto useful compounds, butin breaking the bond to convert the N2releasing Spectral lines ofNitrogenlarge amounts of often useful energy,when these compounds burn, explode,or decay back into nitrogen gas.The element nitrogen was discoveredby Scottish physician DanielRutherford in 1772. Nitrogen occursin all living organisms. It is aconstituent element of amino acidsand thus of proteins, and of nucleicacids (DNA and RNA). It resides in thechemical structure of almost all neurotransmitters, and is a defining component of alkaloids, biological molecules produced by many organisms.Oxygen (OK-si-jin; from the Greek roots ὀξύς (oxys) (acid, literally "sharp", from the sour taste of acids) and -γενής (-genēs) (producer, literally begetter)) is the element with atomic number 8 and represented by the symbol O. It is a member of the chalcogen group on the periodic table, and is a highly reactive nonmetallic period 2 element that readily forms compounds (notably oxides) with almost all other elements. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless, odorless, tasteless diatomic gas with the . Oxygen is the third most abundant element in the universe formula O2by mass after hydrogen and helium[1]and the most abundant element by mass in the Earth's crust.[2] Diatomic oxygen gas constitutes 20.8% of the volume of air.[3]All major classes of structural molecules in living organisms, such as proteins, carbohydrates, and fats, contain oxygen, as do the major inorganic compounds that comprise animal shells, teeth, and bone. Oxygen is produced from water by cyanobacteria, algae and plants in the form of O2during photosynthesis and is used in cellular respiration for all complex life. Oxygen is toxic to obligately anaerobic organisms, which were thebegan to accumulate in the dominant form of early life on Earth until O2atmosphere 2.5 billion years ago.[4]Another form (allotrope) of oxygen, ozone (O), helps protect the biosphere from ultraviolet radiation with3the high-altitude ozone layer, but is a pollutant near the surface where it is a by-product of smog. At even higher low earth orbit altitudes atomic oxygen is a significant presence and a cause of erosion for spacecraft.[5] Oxygen was independently discovered by Carl Wilhelm Scheele, in Uppsala, in 1773 or earlier, and Joseph Priestley in Wiltshire, in 1774, but Priestley is often given priority because his publication came out in print first. The name oxygen was coined in 1777 by Antoine Lavoisier,[6]whose experiments with oxygen helped to discredit the then-popular phlogiston theory of combustion and corrosion. Oxygen is produced industrially by fractional distillation of liquefied air, use of zeolites to remove carbon dioxide and nitrogen from air,electrolysis of water and other means. Uses of oxygen include the production of steel, plastics and textiles; rocket propellant; oxygen therapy; and life support in aircraft, submarines, spaceflight and diving.Fluorine is the chemical element with atomic number 9, represented by the symbol F. Fluorine forms a single bond with itself in elemental form,resulting in the diatomic F2 molecule. F2(fluorine) is a supremelyreactive, poisonous, pale, yellowish brown gas. Elemental fluorine is the most chemically reactive and electronegative of all the elements. For example, it will readily "burn" hydrocarbons at room temperature, in contrast to the combustion of hydrocarbons by oxygen, which requires an input of energy with a spark. Therefore, molecular fluorine is highly dangerous, more so than other halogens such as the poisonous chlorine gas.Fluorine's highest electronegativityand small atomic radius give uniqueproperties to many of its compounds.For example, the enrichment of 235U,the principal nuclear fuel, relies onthe volatility of UF6. Also, thecarbon–fluorine bond is one of thestrongest bonds in organic chemistry. Tan or Yellow gasThis contributes to the stability and persistence of fluoroalkane based organofluorine compounds, such as PTFE/(Teflon) and PFOS. Thecarbon–fluorine bond's inductive effects result in the strength of many fluorinated acids, such as triflic acid and trifluoroacetic acid. Drugs are often fluorinated at biologically reactive positions, to prevent their metabolism and prolong their half-lives.Neon is the chemical element that has the symbol Ne and an atomic number of 10. Although a very common element in the universe, it is rare on Earth.A colourless, inert noble gas under standard conditions, neon gives a distinct reddish-orange glow when used in discharge tubes and neon lampsand advertising signs.[4][5] It iscommercially extracted from air, in whichit is found in trace amounts.Neon is the second lightest inert gas.Neon has three stable isotopes: 20Ne(90.48%), 21Ne (0.27%) and 22Ne (9.25%).21Ne and 22Ne are nucleogenic and their variations are well understood. In contrast, 20Ne (the cosmogenicprimordial isotope made in stellar nucleosynthesis) is not known to be nucleogenic, save for cluster decay production, which is thought to produce only a small amount. The causes of the variation of 20Ne in theEarth have thus been hotly debated.[9] The principal nuclear reactionswhich generate neon isotopes are neutron emission, alpha decay reactionson 24Mg and 25Mg, which produce 21Ne and 22Ne, respectively. The alpha particles are derived from uranium-series decay chains, while theneutrons are mostly produced by secondary reactions from alpha particles.The net result yields a trend towards lower 20Ne/22Ne and higher 21Ne/22Neratios observed in uranium-rich rocks such as granites. Isotopicanalysis of exposed terrestrial rocks has demonstrated the cosmogenic production of 21Ne. This isotope is generated by spallation reactions on magnesium, sodium, silicon, and aluminium. By analyzing all three isotopes, the cosmogenic component can be resolved from magmatic neonand nucleogenic neon. This suggests that neon will be a useful tool in determining cosmic exposure ages of surficial rocks and meteorites.[10]Similar to xenon, neon content observed in samples of volcanic gases are enriched in 20Ne, as well as nucleogenic 21Ne, relative to 22Ne content.The neon isotopic content of these mantle-derived samples represents anon-atmospheric source of neon. The 20Ne-enriched components areattributed to exotic primordial rare gas components in the Earth,possibly representing solar neon. Elevated 20Ne abundances are found in diamonds, further suggesting a solar neon reservoir in the Earth.Neon is the second-lightest noble gas. It glows reddish-orange in a vacuum discharge tube. According to recent studies, neon is the least reactive noble gas and thus the least reactive of all elements.[12]Also,neon has the narrowest liquid range of any element: from 24.55 K to 27.05K (−248.45 °C to −245.95 °C, or −415.21 °F to −410.71 °F). It has over 40 times the refrigerating capacity of liquid helium and three times that of liquid hydrogen (on a per unit volume basis).[13] In most applications it is a less expensive refrigerant than helium.[14]Sodium (/ˈsoʊdiəm/SOH-dee-əm) is a metallic element with a symbol Na(from Latin natrium or Arabic نورتانnatrun; perhaps ultimately fromEgyptian netjerj) and a tomic number11. It is a soft, silvery-white,highly reactive metal and is a memberof the alkali metals within "group 1"(formerly known as ‘group IA’). Ithas only one stable isotope, 23Na.Elemental sodium was first isolatedby Humphry Davy in 1807 by passing anelectric current through molten sodium hydroxide. Elemental sodium does not occur naturally on Earth, because it quickly oxidizes in air and is violently reactive with water, so it must be stored in an inert medium, such as a liquid hydrocarbon. The free metal is used for some chemical synthesis, analysis, and heat transfer applications.Sodium ion is soluble in water in nearly all of its compounds, and is thus present in great quantities in the Earth's oceans and other stagnant bodies of water. In these bodies it is mostly counterbalanced by the chloride ion, causing evaporated ocean water solids to consist mostly of sodium chloride, or common table salt. Sodium ion is also a component of many minerals.Sodium is an essential element for all animal life (including human) and for some plant species. In animals, sodium ions are used in opposition to potassium ions, to allow the organism to build up an electrostatic charge on cell membranes, and thus allow transmission of nerve impulses when the charge is allowed to dissipate by a moving wave of voltage change. Sodium is thus classified as a “dietary inorganic macro-mineral” for animals. Sodium's relative rarity on land is due to its solubility inwater, thus causing it to be leached into bodies of long-standing water by rainfall. Such is its relatively large requirement in animals, in contrast to its relative scarcity in many inland soils, that herbivorous land animals have developed a special taste receptor for the sodium ionMagnesium(/mæɡˈn iːziəm/mag-NEE-zee-əm) is a chemical element withthe symbol Mg, atomic number 12 and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust, where it constitutes about 2% by mass,[2]and ninth in theknown Universe as a whole.[3][4] Thispreponderance of magnesium is relatedto the fact that it is easily built upin supernova stars from a sequentialaddition of three helium nuclei tocarbon (which in turn is made fromthree helium nuclei). Magnesium ion'shigh solubility in water helps ensurethat it is the third most abundantelement dissolved in seawater.[5]Magnesium is the 11th most abundant element by mass in the human body; its ions are essential to all living cells, where they play a major role in manipulating important biological polyphosphate compounds like ATP, DNA, and RNA. Hundreds of enzymes thus require magnesium ions to function. Magnesium is also the metallic ion at the center of chlorophyll, and is thus a common additive to fertilizers.[6] Magnesium compounds are used medicinally as common laxatives, antacids (i.e., milk of magnesia), and in a number of situations where stabilization of abnormal nerve excitation and blood vessel spasm is required (i.e., to treat eclampsia). Magnesium ions are sour to the taste, and in low concentrations help to impart a natural tartness to fresh mineral waters.The free element (metal) is not found naturally on Earth, as it is highly reactive (though once produced, is coated in a thin layer of oxide (see passivation), which partly masks this reactivity). The free metal burnswith a characteristic brilliant white light, making it a useful ingredient in flares. The metal is now mainly obtained by electrolysis of magnesium salts obtained from brine. Commercially, the chief use for the metal is as an alloying agent to make aluminium-magnesium alloys, sometimes called "magnalium" or "magnelium". Since magnesium is less dense than aluminium, these alloys are prized for their relative lightness and strength.Aluminium (UK i/ˌæljʉˈmɪniəm/AL-ew-MIN-ee-əm)[5] or aluminum (US i/əˈl uːmɪnəm/ə-LOO-mi-nəm) is a silvery white member of the boron groupof chemical elements. It has the symbol Al and its atomic number is 13. It is not soluble in water under normal circumstances. Aluminium is the most abundant metal in the Earth's crust, and the third most abundant element, after oxygen and silicon. It makes up about 8% by weight of the Earth's solid surface. Aluminium istoo reactive chemically to occur innature as a free metal. Instead, it isfound combined in over 270 differentminerals.[6] The chief source ofaluminium is bauxite ore.Aluminium is remarkable for themetal's low density and for its abilityto resist corrosion due to thephenomenon of passivation. Structuralcomponents made from aluminium and itsalloys are vital to the aerospaceindustry and are very important inother areas of transportation and building. Its reactive nature makes it useful as a catalyst or additive in chemical mixtures, including ammonium nitrate explosives, to enhance blast power.Silicon(/ˈsɪlɪkən/SIL-ə-kən or /ˈsɪlɪkɒn/SIL-ə-kon; Latin: silicium) isthe most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon.Silicon is the eighth most common element in the universe by mass, but silicon very rarely occurs as the purefree element in nature. It is morewidely distributed in dusts, sands,planetoids and planets as variousforms of silicon dioxide (s ilica)or silicates. In Earth's crust,silicon is the second most abundantelement after oxygen, making up 25.7%of the crust by mass.[4]Silicon has many industrial uses. It is the principal component of most semiconductor devices, most importantly integrated circuits or microchips. Silicon is widely used in semiconductors because it remains a semiconductor at higher temperatures than the semiconductor germanium and because its native oxide is easily grown in a furnace and forms a better semiconductor/dielectric interface than any other material.In the form of silica and silicates, silicon forms useful glasses, cements, and ceramics. It is also a constituent of silicones, a class-name for various synthetic plastic substances made of silicon, oxygen, carbon and hydrogen, often confused with silicon itself.Silicon is an essential element in biology, although only tiny traces of it appear to be required by animals.[5] It is much more important to the metabolism of plants, particularly many grasses, and silicic acid (a type of silica) forms the basis of the striking array of protective shells of the microscopic diatoms.Phosphorus(/ˈfɒsfərəs/FOS-fər-əs) is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogengroup, phosphorus is commonly foundin inorganic phosphate rocks.Elemental phosphorus exists in twomajor forms – white phosphorus andred phosphorus. Although the term (yellow cut), red, violet and black phosphorus "phosphorescence", meaning glow after illumination, derives from phosphorus, glow of phosphorus originates from oxidation of the waxy white white (but not red) phosphorus and should be called chemiluminescence.Due to its high reactivity, phosphorus is never found as a free element in nature on Earth. The first form of phosphorus to be discovered (white phosphorus, in 1669) emits a faint glow upon exposure to oxygen –hence its name given from Greek mythology, Φωσφόρος meaning"light-bearer" (Latin Lucifer), referring to the "Morning Star", the planet Venus.Phosphorus is a component of DNA, RNA, ATP, and also the phospholipids that form all cell membranes. It is, thus, an essential element for all living cells. The most important commercial use of phosphorus-based chemicals is the production of fertilizers.Phosphorus compounds are also widely used in explosives, nerve agents, friction matches, fireworks, pesticides, toothpaste, and detergents.Sulfur or sulphur(/ˈsʌlfər/SUL-fər;see spelling below) is the chemicalelement that has the atomic number 16.It is denoted with the symbol S. Itis an abundant, multivalentnon-metal. Sulfur, in its nativeform, is a bright yellow crystallinesolid. In nature, it can be found asthe pure element and as sulfide andsulfate minerals. It is an essential Spectral lines of Sulfur。

Bandstructures and Density of States 能带以及态密度

Free Electrons
Recap The Brillouin zone Band structure DOS Phonons
Free Electrons
Recap The Brillouin zone Band structure DOS Phonons
Each state has an energy that changes with k – they form energy bands in reciprocal space. Recall that the energies are periodic in reciprocal-space – there are parabolae centred on each of the reciprocal lattice points.
Free Electrons
Recap The Brillouin zone Band structure DOS Phogs get complicated. In general the reciprocal lattice vectors do not form a simple cubic lattice, and the Brillouin zone can have all kinds of shapes.
First Brillouin Zone (2D)
The region of reciprocal space nearer to the origin than any other allowed wavevector is called the 1st Brillouin zone.
Recap The Brillouin zone Band structure DOS Phonons

Universities in Evolutionary Systems(系统变革中的大学)

Universities in Evolutionary Systems of InnovationMarianne van der Steen and Jurgen EndersThis paper criticizes the current narrow view on the role of universities in knowledge-based economies.We propose to extend the current policy framework of universities in national innovation systems(NIS)to a more dynamic one,based on evolutionary economic principles. The main reason is that this dynamic viewﬁts better with the practice of innovation processes. We contribute on ontological and methodological levels to the literature and policy discussions on the effectiveness of university-industry knowledge transfer and the third mission of uni-versities.We conclude with a discussion of the policy implications for the main stakeholders.1.IntroductionU niversities have always played a major role in the economic and cultural devel-opment of countries.However,their role and expected contribution has changed sub-stantially over the years.Whereas,since1945, universities in Europe were expected to con-tribute to‘basic’research,which could be freely used by society,in recent decades they are expected to contribute more substantially and directly to the competitiveness ofﬁrms and societies(Jaffe,2008).Examples are the Bayh–Dole Act(1982)in the United States and in Europe the Lisbon Agenda(2000–2010) which marked an era of a changing and more substantial role for universities.However,it seems that this‘new’role of universities is a sort of universal given one(ex post),instead of an ex ante changing one in a dynamic institutional environment.Many uni-versities are expected nowadays to stimulate a limited number of knowledge transfer activi-ties such as university spin-offs and university patenting and licensing to demonstrate that they are actively engaged in knowledge trans-fer.It is questioned in the literature if this one-size-ﬁts-all approach improves the usefulness and the applicability of university knowledge in industry and society as a whole(e.g.,Litan et al.,2007).Moreover,the various national or regional economic systems have idiosyncratic charac-teristics that in principle pose different(chang-ing)demands towards universities.Instead of assuming that there is only one‘optimal’gov-ernance mode for universities,there may bemultiple ways of organizing the role of univer-sities in innovation processes.In addition,we assume that this can change over time.Recently,more attention in the literature hasfocused on diversity across technologies(e.g.,King,2004;Malerba,2005;Dosi et al.,2006;V an der Steen et al.,2008)and diversity offormal and informal knowledge interactionsbetween universities and industry(e.g.,Cohenet al.,1998).So far,there has been less atten-tion paid to the dynamics of the changing roleof universities in economic systems:how dothe roles of universities vary over time andwhy?Therefore,this article focuses on the onto-logical premises of the functioning of univer-sities in innovation systems from a dynamic,evolutionary perspective.In order to do so,we analyse the role of universities from theperspective of an evolutionary system ofinnovation to understand the embeddednessof universities in a dynamic(national)systemof science and innovation.The article is structured as follows.InSection2we describe the changing role ofuniversities from the static perspective of anational innovation system(NIS),whereasSection3analyses the dynamic perspective ofuniversities based on evolutionary principles.Based on this evolutionary perspective,Section4introduces the characteristics of a LearningUniversity in a dynamic innovation system,summarizing an alternative perception to thestatic view of universities in dynamic economicsystems in Section5.Finally,the concludingVolume17Number42008doi:10.1111/j.1467-8691.2008.00496.x©2008The AuthorsJournal compilation©2008Blackwell Publishingsection discusses policy recommendations for more effective policy instruments from our dynamic perspective.2.Static View of Universities in NIS 2.1The Emergence of the Role of Universities in NISFirst we start with a discussion of the literature and policy reports on national innovation system(NIS).The literature on national inno-vation systems(NIS)is a relatively new and rapidly growingﬁeld of research and widely used by policy-makers worldwide(Fagerberg, 2003;Balzat&Hanusch,2004;Sharif,2006). The NIS approach was initiated in the late 1980s by Freeman(1987),Dosi et al.(1988)and Lundvall(1992)and followed by Nelson (1993),Edquist(1997),and many others.Balzat and Hanusch(2004,p.196)describe a NIS as‘a historically grown subsystem of the national economy in which various organizations and institutions interact with and inﬂuence one another in the carrying out of innovative activity’.It is about a systemic approach to innovation,in which the interaction between technology,institutions and organizations is central.With the introduction of the notion of a national innovation system,universities were formally on the agenda of many innovation policymakers worldwide.Clearly,the NIS demonstrated that universities and their interactions with industry matter for innova-tion processes in economic systems.Indeed, since a decade most governments acknowl-edge that interactions between university and industry add to better utilization of scienti-ﬁc knowledge and herewith increase the innovation performance of nations.One of the central notions of the innovation system approach is that universities play an impor-tant role in the development of commercial useful knowledge(Edquist,1997;Sharif, 2006).This contrasts with the linear model innovation that dominated the thinking of science and industry policy makers during the last century.The linear innovation model perceives innovation as an industry activity that‘only’utilizes fundamental scientiﬁc knowledge of universities as an input factor for their innovative activities.The emergence of the non-linear approach led to a renewed vision on the role–and expectations–of universities in society. Some authors have referred to a new social contract between science and society(e.g., Neave,2000).The Triple Helix(e.g.,Etzkowitz &Leydesdorff,1997)and the innovation system approach(e.g.,Lundvall,1988)and more recently,the model of Open Innovation (Chesbrough,2003)demonstrated that innova-tion in a knowledge-based economy is an inter-active process involving many different innovation actors that interact in a system of overlapping organizationalﬁelds(science, technology,government)with many interfaces.2.2Static Policy View of Universities in NIS Since the late1990s,the new role of universi-ties in NIS thinking emerged in a growing number of policy studies(e.g.,OECD,1999, 2002;European Commission,2000).The con-tributions of the NIS literature had a large impact on policy makers’perception of the role of universities in the national innovation performance(e.g.,European Commission, 2006).The NIS approach gradually replaced linear thinking about innovation by a more holistic system perspective on innovations, focusing on the interdependencies among the various agents,organizations and institutions. NIS thinking led to a structurally different view of how governments can stimulate the innovation performance of a country.The OECD report of the national innovation system (OECD,1999)clearly incorporated these new economic principles of innovation system theory.This report emphasized this new role and interfaces of universities in knowledge-based economies.This created a new policy rationale and new awareness for technology transfer policy in many countries.The NIS report(1999)was followed by more attention for the diversity of technology transfer mecha-nisms employed in university-industry rela-tions(OECD,2002)and the(need for new) emerging governance structures for the‘third mission’of universities in society,i.e.,patent-ing,licensing and spin-offs,of public research organizations(OECD,2003).The various policy studies have in common that they try to describe and compare the most important institutions,organizations, activities and interactions of public and private actors that take part in or inﬂuence the innovation performance of a country.Figure1 provides an illustration.Theﬁgure demon-strates the major building blocks of a NIS in a practical policy setting.It includesﬁrms,uni-versities and other public research organiza-tions(PROs)involved in(higher)education and training,science and technology.These organizations embody the science and tech-nology capabilities and knowledge fund of a country.The interaction is represented by the arrows which refer to interactive learn-ing and diffusion of knowledge(Lundvall,Volume17Number42008©2008The AuthorsJournal compilation©2008Blackwell Publishing1992).1The building block ‘Demand’refers to the level and quality of demand that can be a pull factor for ﬁrms to innovate.Finally,insti-tutions are represented in the building blocks ‘Framework conditions’and ‘Infrastructure’,including various laws,policies and regula-tions related to science,technology and entre-preneurship.It includes a very broad array of policy issues from intellectual property rights laws to ﬁscal instruments that stimulate labour mobility between universities and ﬁrms.The ﬁgure demonstrates that,in order to improve the innovation performance of a country,the NIS as a whole should be conducive for innovative activities in acountry.Since the late 1990s,the conceptual framework as represented in Figure 1serves as a dominant design for many comparative studies of national innovation systems (Polt et al.,2001;OECD,2002).The typical policy benchmark exercise is to compare a number of innovation indicators related to the role of university-industry interactions.Effective performance of universities in the NIS is judged on a number of standardized indica-tors such as the number of spin-offs,patents and licensing.Policy has especially focused on ‘getting the incentives right’to create a generic,good innovative enhancing context for ﬁrms.Moreover,policy has also inﬂu-enced the use of speciﬁc ‘formal’transfer mechanisms,such as university patents and university spin-offs,to facilitate this collabo-ration.In this way best practice policies are identiﬁed and policy recommendations are derived:the so-called one-size-ﬁts-all-approach.The focus is on determining the ingredients of an efﬁcient benchmark NIS,downplaying institutional diversity and1These organizations that interact with each other sometimes co-operate and sometimes compete with each other.For instance,ﬁrms sometimes co-operate in certain pre-competitive research projects but can be competitors as well.This is often the case as well withuniversities.Figure 1.The Benchmark NIS Model Source :Bemer et al.(2001).Volume 17Number 42008©2008The AuthorsJournal compilation ©2008Blackwell Publishingvariety in the roles of universities in enhanc-ing innovation performance.The theoretical contributions to the NIS lit-erature have outlined the importance of insti-tutions and institutional change.However,a further theoretical development of the ele-ments of NIS is necessary in order to be useful for policy makers;they need better systemic NIS benchmarks,taking systematically into account the variety of‘national idiosyncrasies’. Edquist(1997)argues that most NIS contribu-tions are more focused onﬁrms and technol-ogy,sometimes reducing the analysis of the (national)institutions to a left-over category (Geels,2005).Following Hodgson(2000), Nelson(2002),Malerba(2005)and Groenewe-gen and V an der Steen(2006),more attention should be paid to the institutional idiosyncra-sies of the various systems and their evolution over time.This creates variety and evolving demands towards universities over time where the functioning of universities and their interactions with the other part of the NIS do evolve as well.We suggest to conceptualize the dynamics of innovation systems from an evolutionary perspective in order to develop a more subtle and dynamic vision on the role of universities in innovation systems.We emphasize our focus on‘evolutionary systems’instead of national innovation systems because for many universities,in particular some science-based disciplinaryﬁelds such as biotechnology and nanotechnology,the national institutional environment is less relevant than the institu-tional and technical characteristics of the technological regimes,which is in fact a‘sub-system’of the national innovation system.3.Evolutionary Systems of Innovation as an Alternative Concept3.1Evolutionary Theory on Economic Change and InnovationCharles Darwin’s The Origin of Species(1859)is the foundation of modern thinking about change and evolution(Luria et al.,1981,pp. 584–7;Gould,1987).Darwin’s theory of natural selection has had the most important consequences for our perception of change. His view of evolution refers to a continuous and gradual adaptation of species to changes in the environment.The idea of‘survival of theﬁttest’means that the most adaptive organisms in a population will survive.This occurs through a process of‘natural selection’in which the most adaptive‘species’(organ-isms)will survive.This is a gradual process taking place in a relatively stable environment, working slowly over long periods of time necessary for the distinctive characteristics of species to show their superiority in the‘sur-vival contest’.Based on Darwin,evolutionary biology identiﬁes three levels of aggregation.These three levels are the unit of variation,unit of selection and unit of evolution.The unit of varia-tion concerns the entity which contains the genetic information and which mutates fol-lowing speciﬁc rules,namely the genes.Genes contain the hereditary information which is preserved in the DNA.This does not alter sig-niﬁcantly throughout the reproductive life-time of an organism.Genes are passed on from an organism to its successors.The gene pool,i.e.,the total stock of genetic structures of a species,only changes in the reproduction process as individuals die and are born.Par-ticular genes contribute to distinctive charac-teristics and behaviour of species which are more or less conducive to survival.The gene pool constitutes the mechanism to transmit the characteristics of surviving organisms from one generation to the next.The unit of selection is the expression of those genes in the entities which live and die as individual specimens,namely(individual) organisms.These organisms,in their turn,are subjected to a process of natural selection in the environment.‘Fit’organisms endowed with a relatively‘successful’gene pool,are more likely to pass them on to their progeny.As genes contain information to form and program the organisms,it can be expected that in a stable environment genes aiding survival will tend to become more prominent in succeeding genera-tions.‘Natural selection’,thus,is a gradual process selecting the‘ﬁttest’organisms. Finally,there is the unit of evolution,or that which changes over time as the gene pool changes,namely populations.Natural selec-tion produces changes at the level of the population by‘trimming’the set of genetic structures in a population.We would like to point out two central principles of Darwinian evolution.First,its profound indeterminacy since the process of development,for instance the development of DNA,is dominated by time at which highly improbable events happen (Boulding,1991,p.12).Secondly,the process of natural selection eliminates poorly adapted variants in a compulsory manner,since indi-viduals who are‘unﬁt’are supposed to have no way of escaping the consequences of selection.22We acknowledge that within evolutionary think-ing,the theory of Jean Baptiste Lamarck,which acknowledges in essence that acquired characteris-tics can be transmitted(instead of hereditaryVolume17Number42008©2008The AuthorsJournal compilation©2008Blackwell PublishingThese three levels of aggregation express the differences between ‘what is changing’(genes),‘what is being selected’(organisms),and ‘what changes over time’(populations)in an evolutionary process (Luria et al.,1981,p.625).According to Nelson (see for instance Nelson,1995):‘Technical change is clearly an evolutionary process;the innovation generator keeps on producing entities superior to those earlier in existence,and adjustment forces work slowly’.Technological change and innovation processes are thus ‘evolutionary’because of its characteristics of non-optimality and of an open-ended and path-dependent process.Nelson and Winter (1982)introduced the idea of technical change as an evolutionary process in capitalist economies.Routines in ﬁrms function as the relatively durable ‘genes’.Economic competition leads to the selection of certain ‘successful’routines and these can be transferred to other ﬁrms by imitation,through buy-outs,training,labour mobility,and so on.Innovation processes involving interactions between universities and industry are central in the NIS approach.Therefore,it seems logical that evolutionary theory would be useful to grasp the role of universities in innovation pro-cesses within the NIS framework.3.2Evolutionary Underpinnings of Innovation SystemsBased on the central evolutionary notions as discussed above,we discuss in this section how the existing NIS approaches have already incor-porated notions in their NIS frameworks.Moreover,we investigate to what extent these notions can be better incorporated in an evolu-tionary innovation system to improve our understanding of universities in dynamic inno-vation processes.We focus on non-optimality,novelty,the anti-reductionist methodology,gradualism and the evolutionary metaphor.Non-optimality (and Bounded Rationality)Based on institutional diversity,the notion of optimality is absent in most NIS approaches.We cannot deﬁne an optimal system of innovation because evolutionary learning pro-cesses are important in such systems and thus are subject to continuous change.The system never achieves an equilibrium since the evolu-tionary processes are open-ended and path dependent.In Nelson’s work (e.g.,1993,1995)he has emphasized the presence of contingent out-comes of innovation processes and thus of NIS:‘At any time,there are feasible entities not present in the prevailing system that have a chance of being introduced’.This continuing existence of feasible alternative developments means that the system never reaches a state of equilibrium or ﬁnality.The process always remains dynamic and never reaches an optimum.Nelson argues further that diversity exists because technical change is an open-ended multi-path process where no best solu-tion to a technical problem can be identiﬁed ex post .As a consequence technical change can be seen as a very wasteful process in capitalist economies with many duplications and dead-ends.Institutional variety is closely linked to non-optimality.In other words,we cannot deﬁne the optimal innovation system because the evolutionary learning processes that take place in a particular system make it subject to continuous change.Therefore,comparisons between an existing system and an ideal system are not possible.Hence,in the absence of any notion of optimality,a method of comparing existing systems is necessary.According to Edquist (1997),comparisons between systems were more explicit and systematic than they had been using the NIS approaches.Novelty:Innovations CentralNovelty is already a central notion in the current NIS approaches.Learning is inter-preted in a broad way.Technological innova-tions are deﬁned as combining existing knowledge in new ways or producing new knowledge (generation),and transforming this into economically signiﬁcant products and processes (absorption).Learning is the most important process behind technological inno-vations.Learning can be formal in the form of education and searching through research and development.However,in many cases,innovations are the consequence of several kinds of learning processes involving many different kinds of economic agents.According to Lundvall (1992,p.9):‘those activities involve learning-by-doing,increasing the efﬁciency of production operations,learning-characteristics as in the theory of Darwin),is acknowledged to ﬁt better with socio-economic processes of technical change and innovation (e.g.,Nelson &Winter,1982;Hodgson,2000).Therefore,our theory is based on Lamarckian evolutionary theory.However,for the purpose of this article,we will not discuss the differences between these theo-ries at greater length and limit our analysis to the fundamental evolutionary building blocks that are present in both theories.Volume 17Number 42008©2008The AuthorsJournal compilation ©2008Blackwell Publishingby-using,increasing the efﬁciency of the use of complex systems,and learning-by-interacting, involving users and producers in an interac-tion resulting in product innovations’.In this sense,learning is part of daily routines and activities in an economy.In his Learning Economy concept,Lundvall makes learning more explicit,emphasizing further that ‘knowledge is assumed as the most funda-mental resource and learning the most impor-tant process’(1992,p.10).Anti-reductionist Approach:Systems and Subsystems of InnovationSo far,NIS approaches are not yet clear and systematic in their analysis of the dynamics and change in innovation systems.Lundvall’s (1992)distinction between subsystem and system level based on the work of Boulding implicitly incorporates both the actor(who can undertake innovative activities)as well as the structure(institutional selection environment) in innovation processes of a nation.Moreover, most NIS approaches acknowledge that within the national system,there are different institu-tional subsystems(e.g.,sectors,regions)that all inﬂuence each other again in processes of change.However,an explicit analysis of the structured environment is still missing (Edquist,1997).In accordance with the basic principles of evolutionary theory as discussed in Section 3.1,institutional evolutionary theory has developed a very explicit systemic methodol-ogy to investigate the continuous interaction of actors and institutional structures in the evolution of economic systems.The so-called ‘methodological interactionism’can be per-ceived as a methodology that combines a structural perspective and an actor approach to understand processes of economic evolu-tion.Whereas the structural perspective emphasizes the existence of independent institutional layers and processes which deter-mine individual actions,the actor approach emphasizes the free will of individuals.The latter has been referred to as methodological individualism,as we have seen in neo-classical approaches.Methodological indi-vidualism will explain phenomena in terms of the rational individual(showingﬁxed prefer-ences and having one rational response to any fully speciﬁed decision problem(Hodgson, 2000)).The interactionist approach recognizes a level of analysis above the individual orﬁrm level.NIS approaches recognize that national differences exist in terms of national institu-tions,socio-economic factors,industries and networks,and so on.So,an explicit methodological interactionist approach,explicitly recognizing various insti-tutional layers in the system and subsystem in interaction with the learning agents,can improve our understanding of the evolution of innovation.Gradualism:Learning Processes andPath-DependencyPath-dependency in biology can be translated in an economic context in the form of(some-times very large)time lags between a technical invention,its transformation into an economic innovation,and the widespread diffusion. Clearly,in many of the empirical case studies of NIS,the historical dimension has been stressed.For instance,in the study of Denmark and Sweden,it has been shown that the natural resource base(for Denmark fertile land,and for Sweden minerals)and economic history,from the period of the Industrial Revolution onwards,has strongly inﬂuenced present specialization patterns(Edquist& Lundvall,1993,pp.269–82).Hence,history matters in processes of inno-vation as the innovation processes are inﬂu-enced by many institutions and economic agents.In addition,they are often path-dependent as small events are reinforced and become crucially important through processes of positive feedback,in line with evolutionary processes as discussed in Section3.1.Evolutionary MetaphorFinally,most NIS approaches do not explicitly use the biological metaphor.Nevertheless, many of the approaches are based on innova-tion theories in which they do use an explicit evolutionary metaphor(e.g.,the work of Nelson).To summarize,the current(policy)NIS approaches have already implicitly incorpo-rated some evolutionary notions such as non-optimality,novelty and gradualism.However, what is missing is a more explicit analysis of the different institutional levels of the economic system and innovation subsystems (their inertia and evolution)and how they change over time in interaction with the various learning activities of economic agents. These economic agents reside at established ﬁrms,start-upﬁrms,universities,govern-ments,undertaking learning and innovation activities or strategic actions.The explicit use of the biological metaphor and an explicit use of the methodological interactionst approach may increase our understanding of the evolu-tion of innovation systems.Volume17Number42008©2008The AuthorsJournal compilation©2008Blackwell Publishing4.Towards a Dynamic View of Universities4.1The Logic of an Endogenous‘Learning’UniversityIf we translate the methodological interaction-ist approach to the changing role of universities in an evolutionary innovation system,it follows that universities not only respond to changes of the institutional environment(government policies,business demands or changes in scientiﬁc paradigms)but universities also inﬂuence the institutions of the selection envi-ronment by their strategic,scientiﬁc and entre-preneurial actions.Moreover,these actions inﬂuence–and are inﬂuenced by–the actions of other economic agents as well.So,instead of a one-way rational response by universities to changes(as in reductionist approach),they are intertwined in those processes of change.So, universities actually function as an endogenous source of change in the evolution of the inno-vation system.This is(on an ontological level) a fundamental different view on the role of universities in innovation systems from the existing policy NIS frameworks.In earlier empirical research,we observed that universities already effectively function endogenously in evolutionary innovation system frameworks;universities as actors (already)develop new knowledge,innovate and have their own internal capacity to change,adapt and inﬂuence the institutional development of the economic system(e.g., V an der Steen et al.,2009).Moreover,univer-sities consist of a network of various actors, i.e.,the scientists,administrators at technology transfer ofﬁces(TTO)as well as the university boards,interacting in various ways with indus-try and governments and embedded in various ways in the regional,national or inter-national environment.So,universities behave in an at least partly endogenous manner because they depend in complex and often unpredictable ways on the decision making of a substantial number of non-collusive agents.Agents at universities react in continuous interaction with the learn-ing activities ofﬁrms and governments and other universities.Furthermore,the endogenous processes of technical and institutional learning of univer-sities are entangled in the co-evolution of institutional and technical change of the evo-lutionary innovation system at large.We propose to treat the learning of universities as an inseparable endogenous variable in the inno-vation processes of the economic system.In order to structure the endogenization in the system of innovation analysis,the concept of the Learning University is introduced.In thenext subsection we discuss the main character-istics of the Learning University and Section5discusses the learning university in a dynamic,evolutionary innovation system.An evolution-ary metaphor may be helpful to make theuniversity factor more transparent in theco-evolution of technical and institutionalchange,as we try to understand how variouseconomic agents interact in learning processes.4.2Characteristics of the LearningUniversityThe evolution of the involvement of universi-ties in innovation processes is a learningprocess,because(we assume that)universitypublic agents have their‘own agenda’.V ariousincentives in the environment of universitiessuch as government regulations and technol-ogy transfer policies as well as the innovativebehaviour of economic agents,compel policymakers at universities to constantly respondby adapting and improving their strategiesand policies,whereas the university scientistsare partly steered by these strategies and partlyinﬂuenced by their own scientiﬁc peers andpartly by their historically grown interactionswith industry.During this process,universityboards try to be forward-looking and tobehave strategically in the knowledge thattheir actions‘inﬂuence the world’(alsoreferred to earlier as‘intentional variety’;see,for instance,Dosi et al.,1988).‘Intentional variety’presupposes that tech-nical and institutional development of univer-sities is a learning process.University agentsundertake purposeful action for change,theylearn from experience and anticipate futurestates of the selective environment.Further-more,university agents take initiatives to im-prove and develop learning paths.An exampleof these learning agents is provided in Box1.We consider technological and institutionaldevelopment of universities as a process thatinvolves many knowledge-seeking activitieswhere public and private agents’perceptionsand actions are translated into practice.3Theinstitutional changes are the result of inter-actions among economic agents deﬁned byLundvall(1992)as interactive learning.Theseinteractions result in an evolutionary pattern3Using a theory developed in one scientiﬁc disci-pline as a metaphor in a different discipline mayresult,in a worst-case scenario,in misleading analo-gies.In the best case,however,it can be a source ofcreativity.As Hodgson(2000)pointed out,the evo-lutionary metaphor is useful for understandingprocesses of technical and institutional change,thatcan help to identify new events,characteristics andphenomena.Volume17Number42008©2008The AuthorsJournal compilation©2008Blackwell Publishing。

详细-介绍石墨烯英文版解析

Graphene is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice The name ‘graphene’ comes from graphite + -ene = graphene
Third, industrial use of graphene as a transparent conductor could have huge implications for the solar industry. As synthetic routes improve, the prospect of replacing ITO with a low-cost carbon-based coating seems feasible. This would not only remove significant uncertainty about the availability and cost of indium but also enable non evaporative roll-to roll processing of transparent conductors.
In 2004: Andre Geim and Kostya Novoselov at Manchester University managed to extract single-atom-thick crystallites (graphene) from bulk graphite: Pulled out graphene layers from graphite and transferred them onto thin silicon dioxide on a silicon wafer in a process sometimes called micromechanical cleavage or, simply, the Scotch tape technique. Since 2004, an explosion in the investigation of graphene in term of synthesis, characterization, properties as well as specifical potential application were reported.

锆合金的研发历史、现状及发展趋势

㊀第41卷㊀第5期2022年5月中国材料进展MATERIALS CHINAVol.41㊀No.5May 2022收稿日期:2021-12-15㊀㊀修回日期:2022-03-22基金项目:国家自然科学基金优青项目(51922082)第一作者:贾豫婕,女,1997年生,博士研究生通讯作者:韩卫忠,男,1981年生,教授,博士生导师,Email:wzhanxjtu@DOI :10.7502/j.issn.1674-3962.202112010锆合金的研发历史㊁现状及发展趋势贾豫婕,林希衡,邹小伟,韩卫忠(西安交通大学金属材料强度国家重点实验室,陕西西安710016)摘㊀要:锆合金作为一种重要的战略材料,被誉为原子能时代的第一金属 ,由于其低中子吸收率㊁抗腐蚀㊁耐高温等优点,被广泛用作核反应堆关键结构材料㊂我国锆合金基础研究及工业化发展起步较晚,锆合金种类较少,因此,锆合金的研发受到了学术界及工业界的广泛重视㊂回顾了核用锆合金研发的历史进程㊁应用现状及未来发展趋势,阐明了锆合金基础研究和开发应用的重要性,简要介绍了新兴的高性能锆合金,包括医用锆合金㊁耐腐蚀锆合金㊁高强高韧锆合金和锆基非晶合金㊂随着核反应堆的升级换代和非核用应用需求的多样化,发展新型锆合金㊁拓展锆合金的应用范围,是锆合金未来研发的着眼点㊂关键词:锆合金;包壳;强韧化;耐蚀性;抗辐照性中图分类号:TG146.4+14;TB31㊀㊀文献标识码:A㊀㊀文章编号:1674-3962(2022)05-0354-17引用格式:贾豫婕,林希衡,邹小伟,等.锆合金的研发历史㊁现状及发展趋势[J].中国材料进展,2022,41(5):354-370.JIA Y J,LIN X H,ZOU X W,et al .Research &Development History,Status and Prospect of Zirconium Alloys[J].Materials China,2022,41(5):354-370.Research &Development History ,Status andProspect of Zirconium AlloysJIA Yujie,LIN Xiheng,ZOU Xiaowei,HAN Weizhong(State Key Laboratory for Mechanical Behavior of Materials,Xi a n Jiaotong University,Xi a n 710016,China)Abstract :Zirconium alloys,as an important strategic material,also widely known as the first metal in the atomic-energyage ,are widely used in nuclear reactors as key structural components because of their small thermal neutron capture cross-section,excellent corrosion resistance and high-temperature mechanical properties.The fundamental research and industrial-ization of zirconium alloy in China is later than that of the developed countries.As a result,our zirconium industries have less variants of products,which attract broad attentions from the academic communities and industry sectors.In this review,we retrospect the development history,application status and future trends of nuclear-related zirconium alloys,and empha-size the importance of accelerating fundamental research and developing new zirconium alloys.The design and development of advanced high-performance zirconium alloys are also briefly introduced,including medical-used zirconium alloys,corro-sion-resistant zirconium alloys,high strength-high toughness zirconium alloys and zirconium-based amorphous alloys.With the requirements of further upgrading of nuclear reactors and the diverse applications,the development of new zirconium al-loys and the broadening of their applications are key points in future research &development of advanced zirconium alloys.Key words :zirconium alloy;fuel cladding;strength-ductility;corrosion resistance;irradiation resistance1㊀前㊀言锆元素的地壳丰度约为1.30ˑ10-4,处于第18位㊂然而,锆矿石全球储量分布不均,如图1a 所示,供需市场严重错位[1]㊂锆的熔点为1852ħ,具有低毒㊁耐腐蚀㊁热中子吸收截面小㊁高温力学性能优良㊁与人体相容性好等优点;其化合物如氧化锆㊁氯氧化锆等具有独特的化学和物理性能㊂因此,锆及锆制品被广泛应用于核工业㊁化学工业㊁陶瓷工业㊁耐火材料工业㊁铸造业㊁航空航天㊁医疗行业等㊂目前,我国锆产业的生产和发展主要有2个特点:一是锆矿石严重依赖进口(图1a);二是主要消费品集中在陶瓷等领域,初级产品占比高㊁产能过剩,整体产业污染高㊁效益低㊁高端产品占比少㊁All Rights Reserved.㊀第5期贾豫婕等:锆合金的研发历史㊁现状及发展趋势自主化程度低[2-4](图1b)㊂因此,亟需合理规划和布局锆行业的发展,提高锆相关产品的技术含量和附加值,打破锆合金高端市场的国际垄断,在国内建立完整高效的锆合金供应链,对整个锆合金行业进行深入思考和规划㊂图1㊀锆资源分布及生产分析:(a)全球锆矿资源分布[1],(b)国内锆合金产业结构分析及预测[2-4]Fig.1㊀Zr reserves and production:(a)world Zr reserves [1],(b)analysis and forecast of China Zr industry [2-4]2㊀核用锆合金的研发现状2.1㊀国外锆合金研发历程核燃料包壳材料选择的多重设计约束包括抗蠕变性能㊁强度㊁韧性㊁抗中子辐照㊁热中子吸收截面㊁高温性能㊁化学兼容性等各种综合性能的限制[5]㊂锆合金在高温材料中具有较低的热中子吸收截面和较为优良的抗辐照能力,自20世纪50年代开始作为核反应堆中重要的结构材料延用至今㊂美国㊁俄罗斯㊁法国及德国等国家自20世纪50年代起先后研发出一系列锆合金㊂受当时的冶炼条件限制,高纯锆在冶炼及加工过程中会不可避免地引入Ti,C,Al,N,Si 等有害杂质,降低了合金的耐腐蚀性能㊂Sn 作为α相稳定元素,能吸收合金中有害杂质[6]㊂因此,美国于1951年研发出了Zr-2.5Sn 合金,即Zr-1合金[7-9]㊂并在Zr-1合金基础上调整合金成分研制出了Zr-2合金(Zr-1.7Sn-0.2Fe-0.1Cr-0.05Ni),但Ni 元素的加入导致Zr-2合金吸氢量增加㊂于是,在Zr-2合金基础上去掉Ni 元素,增加Fe 元素,研制出了Zr-4合金[10]㊂锆合金中较高含量的Sn 不利于进一步提高合金的耐腐蚀性能,之后,随着冶炼技术的发展,通过将Zr-4合金中的Sn 含量控制在较低水平,并通过增加Fe 和Cr 的含量,改进型Zr-4合金得到了发展㊂此外,不同于美国侧重于研发Zr-Sn 系合金,依据Nb 元素较小的热中子吸收截面和强化合金的作用,前苏联发展了E110等Zr-Nb 系合金[11],加拿大开发了Zr-2.5Nb 合金用作CANDU 重水反应堆的压力管材料[12]㊂随着各国不断提高燃料能耗㊁降低循环成本,改进型Zr-4合金已不能满足50GWd /tU 以上的高燃耗要求[13],各种新型高性能锆合金相继被研发并且部分合金已投入生产,如法国的M5合金[14]㊁美国西屋公司的Zirlo 合金[15]㊁前苏联的E635合金[16]㊁日本的NDA 合金[6]㊁韩国的HA-NA 合金[6]等㊂2.2㊀我国锆合金研发历程面对国外长期的技术封锁及国家核工业发展的急需,我国从20世纪60年代初开始了锆合金的研究及工业化生产,期间成功制取了原子能级海绵锆,建设了西北锆管有限责任公司等具有先进水平㊁与中国大型核电站配套发展的现代化企业,生产制造的国产Zr-4合金完全满足工程要求㊂自20世纪90年代初开始,我国研制了以N18(NZ2)和N36(NZ8)合金为代表的具有自主知识产权的第三代锆合金[17,18]㊂21世纪初开始,一批性能优异的CZ 系列㊁SZA 系列锆合金先后启动研发㊂国内外几种典型核用锆合金的成分对比如表1所示[19]㊂作为核工业的重要材料,核级锆材的国产化生产至关重要㊂将国内外重要的锆合金牌号及其相应的研发年份汇总至图2中[6-17],可以发现我国目前已经具备了各类核级锆材的供应能力,建立了较为完整的自主化核级锆材产业体系,但产能较低㊁自主化水平较弱㊂据中国核能行业协会‘2021年核电行业述评及2022年展望“可知,截至2021年12月底,我国大陆地区商运核电机组53台,总装机容量为5463.695万千瓦;在建核电机组16台,总容量是1750.779万千瓦㊂因此,我国的核电产业每年所需锆材约为1071.6~1268.4t,海绵锆约为2143.2~2536.8t [20]㊂目前国核宝钛锆业㊁中核晶环锆业㊁东方锆业的海绵锆年产能分别约为1500,500和150t,总体产能低于每年海绵锆的需求量㊂总体来看,通过加强锆矿石进口海外布局,推动核用锆合金自主化,提高锆合金企业研发能力和生产效益,是突破我国核工业关键材料卡脖子问题㊁确保我国能源安全的关键一步㊂553All Rights Reserved.中国材料进展第41卷表1㊀几种典型核用锆合金的成分[19]Table 1㊀Composition of several typical nuclear Zr alloys [19]Alloy Chemical compositions /wt%Sn Nb FeCrNi Cu Country Zr-2 1.5 0.150.10.05 USA Zr-41.50.220.1 USAE110 1.0USSR E1252.5Canada Zr-2.5Nb-0.5Cu2.5 0.5Canada Zirlo1.01.00.1USAE635 1.20 1.00.4USSR N18(NZ2)1.00.30.30.1ChinaN36(NZ8) 1.01.00.3China图2㊀国内外锆合金研发历程[6-17]Fig.2㊀Research history of Zr alloys [6-17]2.3㊀核用锆材发展趋势锆合金的研发周期长㊁服役要求高,从研发到批量化生产需要经过大量的性能测试和工序调整(见图3),因此,近20年内核反应堆服役的锆合金种类及应用结构部件近乎不变[21-23],目前核反应堆常用锆合金应用情况如表2所示[21-25]㊂但随着三代核反应堆的逐渐发展及应用,在保证核反应堆安全㊁高效㊁经济的前提下,其燃耗㊁服役寿命及可用性需求不断提升[24],如华龙一号平均燃耗达到45000MWd /tU 以上㊁CAP1400的目标燃耗为60000MWd /tU㊁锆合金的换料周期从12个月延长至18个月及以上,这些要求使得各国密切关注锆合金服役性能的提升㊂其中,拟采取的主要措施为多元合金化和改进加工工艺[25]㊂同时,在现有锆合金的基础上进行成分调整也是发展方向之一,如美国西屋电气公司通过将Zirlo 中Sn 的含量从1%下调至0.6%~0.8%,从而得到耐腐蚀性能和抗蠕变性能更加优异的Optimized Zirlo (OPT Zirlo)[26]㊂我国核用锆合金发展现阶段的目标是实现先进压水堆燃料组件用锆合金结构材料的自主产业化㊂目前,我表2㊀核反应堆常用锆合金应用情况[21-25]Table 2㊀The application of representative zirconium alloys in thenuclear reactor [21-25]Designation of zirconium alloy Reactor types UsageZr-2,Zr-4,BWR (boiling water reactor)Fuel cladding,spacers,fuel outer channel,et al .Zr-4,Zirlo,duplex,M5,MDA,NDAPWR (pressurized water reactor)Fuel cladding,guide tube,grid spacers,plug,fuel outer channel,access port,et al .Zr-2,Zr-4,Zr-2.5NbCANDU Pressure tube,calandria tube,fuel cladding,garter springs,plug,et al .E110VVER-440㊁VVER-1000Fuel cladding,grid spacersE110,E635RBMKFuel cladding,guide tube,fuel outer channel,spacers653All Rights Reserved.㊀第5期贾豫婕等:锆合金的研发历史㊁现状及发展趋势图3㊀新型锆合金的研发历程[22]Fig.3㊀The research and development route of a new zirconium alloy [22]国的锆合金研发及应用现状如下:不同型号核反应堆所用的Zr-4合金㊁M5合金和Zirlo 合金已经具备全流程的国产化制造能力,其中Zirlo 合金的入堆服役标志着我国核级锆材国产化目标的实现;国内自主研制的SZA 系列和CZ 系列锆合金堆内测试基本完成,工程化生产及性能评价已进入尾声,预计在2025年之前完成该系列新型锆合金的工程化应用;N36作为华龙一号中CF3核燃料组件的指定包壳材料,已在巴基斯坦卡拉奇核电站2号机组运行使用[27,28]㊂在自主产业化目标即将实现的同时,我国核用锆合金发展的部分问题仍未解决,例如自主研制的核用锆合金种类少,堆内测试地点少,堆内模拟数据库急需建立,针对锆材加工工艺㊁组织分析与堆内外服役性能之间的机理联系研究尚有不足等㊂2.4㊀核用锆材的生产加工技术进展及新型锆合金的开发改进锆合金的生产加工工艺与研制新型锆合金是发展核用锆材的关键㊂近年来,国内外在锆合金的生产加工技术以及合金成分优化方面都取得了重要进展㊂2.4.1㊀锆合金的加工技术进展核用锆合金管件的加工一般采用如图4所示的工艺流程[29],依次包括锆合金铸锭的熔炼㊁铸锭锻造㊁β相区淬火㊁热轧㊁反复的冷轧及退火,最终达到尺寸要求㊂改进锆合金的加工工艺是推动锆合金国产化的重要方面㊂目前,各个核发达国家均建成了从原子能级海绵锆到核图4㊀锆合金管件常规的加工热处理工艺流程图[29]Fig.4㊀Conventional processing and heat treatment process of Zr alloy tube[29]753All Rights Reserved.中国材料进展第41卷级锆合金结构材料的完整产业链㊂其中,美国的华昌㊁西屋电气,法国的法玛通等公司代表了锆合金产业化的世界先进水平㊂近年来,我国在锆合金的加工工艺方面取得了极大进展㊂在锆合金的熔炼工艺方面,采用非自耗真空电弧熔炼法可以得到组织均一㊁性能良好的锆合金,且铸锭的实际化学成分与预期的成分也相吻合;在锆合金的生产方面,通过工程化研究,我国已系统解决了Zr-4合金大规格铸锭(Φ=650mm 及以上)的熔炼技术及成分的均匀化调控技术㊁铸锭低温开坯技术㊁管材低温加工技术及织构调控技术㊁管材的表面处理技术㊁精整及检测技术等;在锆合金的热加工工艺方面,累积退火参数A 为锆锡合金管的加工提供了有效指导[30]㊂国内多家锆合金企业在生产加工技术方面也取得了很大的进步[31]㊂2010~2013年,中国核动力研究设计院联合西北有色金属研究院研制了采用国产两辊轧机两道次轧制㊁配合进口KPW25轧机生产Φ9.5mm ˑ0.57mm 管材的生产工艺,攻克铸锭均匀化熔炼㊁挤压感应加热等技术难题,推动了N36合金科研成果的转化㊂此外,国核锆业股份公司通过消化吸收美国西屋公司Zirlo 合金生产技术,成功熔炼得到核级Zr-4铸锭㊁R60702铸锭及Zirlo 返回料铸锭,实现了锆合金铸锭大规模国产化的新突破,建立了完整自主化的锆材加工生产线㊂综上所述,在锆合金生产加工工艺改进方面,国家还需加大投入力度,强化生产条件建设,加快具有自主知识产权锆合金的产业化生产步伐,实现核用锆合金研发生产加工的自主化,积极参与国际市场竞争㊂2.4.2㊀新型锆合金的研究与开发新型锆合金研发的主要趋势是开发多元合金,在Zr-Sn-Nb 系合金的基础上通过加入多种合金元素,同时提高锆合金的耐腐蚀性能及力学性能等㊂国内外新型核级锆合金的牌号及详细成分详见表3[31,32]㊂由表3可知,近20年来,随着核电技术的进一步发展,各国在新型锆合金成分筛选方面继续探索,美国㊁法国㊁韩国等在已经成功应用的锆合金基础上,开展了成分优化及新合金成分锆合金的研究㊂为打破国外核级锆合金厂商对锆合金成分的垄断,以中国核工业集团有限公司㊁国家核电技术有限公司㊁表3㊀国内外新型锆合金牌号及成分[31,32]Table 3㊀New Zr alloys developed by different countries [31,32]Designation of zirconium alloyChemical compositions /wt%SnNbFeCr Other Country OPT Zirlo0.60~0.790.80~1.200.09~0.13USAX5A0.500.300.350.25USA Valloy0.10 1.10~1.20USA VB 1.00 0.50 1.00USAM5 1.00 Sʒ(0.10~0.35)ˑ10-2Oʒ0.13~0.17France OPT M50.10~0.301.000.10~0.30France J11.80Japan J2 1.60 0.10 Japan J32.50 JapanHANA-40.40 1.500.200.10 Korea HANA-61.10Cuʒ0.05Korea N18(NZ2)0.80~1.200.20~0.400.30~0.400.05~0.10China N36(NZ8)0.80~1.200.90~1.100.10~0.40ChinaC7 0.10 Cuʒ0.01Sʒ0.025China CZ-10.800.250.350.10Cuʒ0.05China CZ-2 1.000.15 Cuʒ0.01China SZA-4/60.50~0.800.25~1.000.20~0.350~0.10Geʒ0.05or Cuʒ0.05or Siʒ0.015China 853All Rights Reserved.㊀第5期贾豫婕等:锆合金的研发历史㊁现状及发展趋势中国广核集团㊁西北有色金属研究院等为代表的核电材料龙头企业及研究机构从20世纪90年代初开始注重开发具有自主知识产权的锆合金㊂在前期研究的基础上,西北有色金属研究院进行了锆合金中试研究,确定了新一代锆合金的合金成分范围和加工工艺,研制出2种新型锆合金NZ2(N18)和NZ8(N36)㊂2009~2011年,西北有色金属研究院依托国家 863 计划项目成功研发了一种Zr-Nb 系锆合金 C7合金㊂2016年,由中广核集团自主研发设计的4组STEP-12核燃料组件和4组高性能核级锆合金(CZ 锆合金)样品管组件正式装入岭澳核电站二期1号机组,随反应堆进行辐照考验,这也标志着中广核集团全面掌握了核燃料组件的研究㊁设计㊁制造和试验技术㊂同时,国核宝钛锆业股份公司自主研发的SZA 新型锆合金紧跟锆合金发展趋势,在Zr-Sn-Nb 系合金的基础上添加微量合金元素Ge,Si 和Cu㊂试验结果表明,SZA 系列合金具有优良的耐腐蚀㊁吸氢和力学性能,有望用于CAP1400燃料组件中㊂2018年,在经过8年的技术攻关之后,我国突破了N36锆合金制备的核心技术环节,成功掌握了具有自主知识产权的完整N36锆合金工程化制备技术,已实现批量化生产,并成功应用于华龙一号 CF3燃料组件的制造,打破了国外长期垄断的局面,解决了我国长期的锆合金出口受限问题[27,28]㊂2.5㊀锆合金的微观组织演化锆合金的再结晶行为,第二相粒子的种类㊁尺寸及分布对锆合金的抗腐蚀性能㊁力学性能有很大的影响㊂此外,锆合金在加工过程中形成的强织构不仅影响锆合金中氢化物的分布特征,还是辐照生长㊁应力腐蚀开裂等的重要诱因㊂因此,锆合金的合金成分和加工工艺对其微观组织和织构演化有重要影响,系统研究锆合金的微观组织演化规律与加工工艺之间的关系是优化锆合金综合性能的基础㊂2.5.1㊀锆合金的微观组织特征核反应堆的极端服役条件要求加工后的锆合金具有均匀的微观组织㊁充分再结晶的晶粒和弥散分布的第二相颗粒等㊂研究表明,通过增加加工变形量或提高热处理温度都会加速Zr-1Nb 合金的再结晶进程[33](见图5)㊂合金元素Mo 的添加大大延缓了Zr-Nb 合金的再结晶过程[34],并且会显著降低Zr-Nb 合金的晶粒尺寸,进而降低合金的塑性㊂含Nb 锆合金的第二相大小及弥散程度与累积退火参数的相关性不强㊂因此,如何在Zr-Nb 合金中获得均匀弥散分布的第二相成为生产加工的重点问题㊂实验表明,N36(NZ8)锆合金中第二相粒子的尺寸㊁数量㊁分布与终轧前热处理的保温温度和保温时间相关[35]㊂经580ħ保温的N36(NZ8)锆合金具有细小且分布均匀的第二相粒子,其耐腐蚀性能较好㊂反之,保温温度的升高或保温时间的延长导致第二相粒子逐渐演化为带状分布,颗粒尺寸增加,耐腐蚀性能显著降低㊂此外,亦有研究发现在650~800ħ保温时,Zr-Nb-Fe 第二相粒子因结构不稳定发生溶解,同时基体析出β-Zr 相[36](见图6)㊂图5㊀Zr-1Nb 合金在580ħ下保温不同时间后的显微组织结构[33]:(a)冷轧变形态,(b)10min,(c)30min,(d)180min;(e)再结晶Zr-1Nb 试样在不同加工变形量㊁热处理温度及退火时间条件下的平均晶粒尺寸Fig.5㊀Microstructures of Zr-1Nb alloy annealed at 580ħfor various time [33]:(a)as-deformed,(b)10min,(c)30min,(d)180min;(e)average grain size of the recrystallized Zr-1Nb specimens subjected to different rolling stain,annealing temperature and annealing time953All Rights Reserved.中国材料进展第41卷图6㊀Zr-Sn-Nb 合金在不同温度保温后淬火得到的显微组织[36]:(a)原始组织,(b)590ħ保温50h,(c)650ħ保温15h,(d)800ħ保温40min,(e)900ħ保温10min,(f)Zr-Nb 二元合金相图富Zr 端Fig.6㊀Microstructure of Zr-Sn-Nb alloy after different temperature of heat preservation [36]:(a)as-received microstructure,(b)590ħ/50h,(c)650ħ/15h,(d)800ħ/40min,(e)900ħ/10min,(f)rich Zr zone of Zr-Nb binary alloy phase diagram2.5.2㊀锆合金的织构锆合金用于核燃料包壳管时,加工织构不仅影响其力学性能,还会影响其辐照生长㊁应力腐蚀开裂和氢脆等行为,因此,加工过程中对锆合金管材织构的控制是十分重要的[37,38]㊂对Zr-Sn-Nb-Fe 新型锆合金管冷轧后的织构分析结果表明[39],管材的织构类型与织构含量随冷加工变形量的变化而变化(如图7所示)㊂冷轧变形前,管材中的主要织构类型为<0001>//周向(TD)和<1120>//轧向(AD)㊂随变形量的增加,<1120>//AD 织构的含量急剧减少,同时<1010>//AD 织构的含量则快速增加,表明取向为<1120>//AD 的晶粒随变形量的增加逐渐转至<1010>//AD㊂图7㊀锆合金管材冷轧变形中织构组分的演化[39]:(a)管材变形锥体示意图,(b)织构组分变化曲线Fig.7㊀Variation of texture component in Zr cladding tube during cold rolling [39]:(a)deformation cone of Zr-Sn-Nb-Fe cladding,(b)tex-ture components evolution with strain [39]㊀㊀Zr-4合金带材是重要的核燃料组件定位格架结构材料,其织构影响辐照生长的倾向,进而影响格架的夹持力[40],因此,如何在生产中控制锆合金带材的织构是一个重要的课题㊂研究发现,β淬火板坯厚度㊁热轧总变形量㊁热轧温度等均会影响Zr-4合金板带材的织构,但热轧变形量的影响最显著[41-43],因此在工业生产中,应主要考虑通过调整热轧变形量来控制锆合金板带材的织构㊂此外,热轧变形量也会对锆合金板材的织构因子,即轧面法向织构因子f n ㊁轧向织构因子f 1以及横向织构因子f t 产生影响㊂增大板材的热轧总变形量能够增大织构因子f n ,同时减小织构因子f 1和f t [43]㊂2.6㊀核用锆合金的堆内(外)性能锆合金在服役过程中始终处于高温㊁高压㊁高应力㊁强辐照的服役环境,且锆合金在高温下极易与用作冷却63All Rights Reserved.㊀第5期贾豫婕等:锆合金的研发历史㊁现状及发展趋势剂的水发生反应,进而引发腐蚀㊁吸氢等一系列问题,因此锆合金的堆内外性能研究受到了广泛的关注㊂2.6.1㊀锆合金的腐蚀性能金属材料的腐蚀反应包括扩散㊁迁移㊁吸附㊁解吸㊁氧化还原和相变等步骤,如图8a所示,其中,影响腐蚀速度的关键因素是氧离子在氧化层中的扩散速率[44]㊂因此,依据Wagner-Hauffle假说[21],可以初步确定锆合金的合金化元素㊂随着锆合金合金成分多元化的发展趋势,腐蚀增重从单一的转折过程变成了复杂的多阶段性过程,如图8b所示,因此,阐明不同成分第二相粒子的耐腐蚀机理变得非常重要㊂通常,第二相的腐蚀速率比基体慢[45,46]㊂当基体被氧化时,内部的第二相被氧化锆包围,均匀弥散分布的第二相可以释放四方相氧化锆内应力,稳定致密柱状晶结构,减缓腐蚀增重转折点的出现㊂而在复杂的服役环境中,中子辐照会造成第二相的溶解和重新分布[47],基于此,有研究[48]建议选择尺寸较大的第二相,从而增加致密氧化层的稳定时间,提高合金耐腐蚀性能㊂图8㊀锆的腐蚀过程示意图[44]:(a)腐蚀中的物质传输,(b)不同合金的整体腐蚀增重曲线Fig.8㊀Illustration of corrosion mechanisms in Zr alloy[44]:(a)ions transportation in corrosion,(b)corrosion weight gain curves of different Zr alloys㊀㊀下面以含Nb(Nb>0.6%,质量分数)锆合金为例简要分析第二相对其腐蚀行为的影响㊂对于含β-Nb的锆合金,延长保温时间以增加β-Nb的析出不一定能够提高基体的耐腐蚀性能,因此,关于β-Nb对基体耐腐蚀性能的影响存在争议[49-52]㊂这种争议的主要原因在于,当合金中含有Fe,Cr,Cu等元素时,其扩散系数比Nb元素高,第二相析出更快,长时间的时效反而会导致其余第二相的析出长大,从而抵消β-Nb的抗腐蚀作用,最终基体的耐腐蚀性能升高不明显㊂总体而言,均匀弥散的β-Nb是具有耐腐蚀作用的,退火参数的选择需要综合不同的合金成分和加工工序进行调整,最终使β-Nb保持弥散㊁均匀的分布㊂近期的研究[53]阐明了β-Zr抗腐蚀能力提高的原因,由于β-Zr会发生共析反应,逐步分解为α-Zr和抗腐蚀性较好的β-Nb,保障了氧化层结构中致密而稳定的四方相氧化锆不断形成,从而降低了基体腐蚀速率㊂除却整体的腐蚀规律,局部腐蚀特征也是研究人员关注的重点,如疖状腐蚀和横向裂纹的产生㊂目前,关于疖状腐蚀的微观机理主要有2种:KUWAE氢聚集模型[54]和周邦新形核长大模型[55](如图9所示)㊂KUWAE氢聚集模型的机理解释为氢聚集在Zr/ZrO2界面上之后巨大的氢压导致氧化膜的破裂,从而使得腐蚀的进一步加剧㊂该模型主要适用于沸水堆[56],这一理论也可以解释大粒径的第二相粒子如何通过影响局部氢传输速度从而导致疖状腐蚀的产生[56]㊂周邦新形核长大模型的机理图9㊀疖状腐蚀机理整体认知:(a)KUWAE氢聚集模型[54],(b)周邦新形核长大模型[55]Fig.9㊀The mechanisms of nodular corrosion:(a)KUWAE model[54],(b)Zhou Bangxin model[55]163All Rights Reserved.中国材料进展第41卷解释是表面取向㊁合金元素㊁析出相局部不均匀导致了氧化膜的局部增厚现象,而氧化膜与基体的内应力不协调使得氧化膜的进一步长大,从而形成了疖状腐蚀㊂而氧化膜与基体的不协调也是横向裂纹产生的主要诱因㊂基于此,研究者[57,58]认为在ZrO2/Zr界面上由于晶体取向的各向异性,引发了第二相的偏聚及氧化层的各向异性生长,从而导致疖状腐蚀的形成[58]㊂随着锆合金合金化元素种类的增加,在今后的研究中,需重点关注不同合金元素带来的腐蚀性能差异,进而建立全面的腐蚀调控理论㊂此外,随着核反应堆向更高堆芯功率密度和更长服役寿命方向发展,对包壳和堆芯结构材料的服役可靠性提出了更高要求,尤其是对锆合金的超高温耐腐蚀性能提出了需求㊂日本福岛核事故中锆包壳与高温水蒸气反应引发氢爆,对现有核燃料组件的安全可靠性敲响了警钟,同时加速推动新型包壳和核燃料组件的研发㊂因此,研发事故容错燃料组件,预防失水事故(LOCA)时锆包壳与高温水蒸气反应引发重大安全事故,是当前的研究热点之一㊂目前,事故容错燃料领域主要包括3种研发思路[59]:①在现有包壳材料表面涂覆涂层,包壳涂层需具备抗氧化性㊁高附着性㊁热膨胀系数匹配㊁耐辐照㊁自我修复㊁高保护性以及制造工艺的稳定性等指标[60],目前的研究主要集中在铬涂层㊁SiC陶瓷涂层㊁高熵合金涂层等;②研究新型燃料包壳材料替换当前的锆合金㊂经过多年的研究,研究者们普遍认为钼合金㊁先进不锈钢[61]㊁SiC基陶瓷复合材料[62]㊁高熵合金[63]等具备代替锆合金的潜力;③研发新型核燃料组件以替代目前的整体UO2基燃料组件,从而大幅度提升核燃料组件的传热效率,降低堆芯温度㊂目前高性能燃料组件的设计思路主要包括美国提出的环形燃料组件[64]和麻花型扭转组件[65]等,其中环形燃料组件的发展较为成熟㊂2.6.2㊀锆合金的抗辐照损伤性能核用锆合金在核反应堆中的服役周期一般为12个月及以上,长时间高剂量中子辐照对锆合金的结构和性能产生重要影响,因此,锆的辐照损伤行为是评价其服役可靠性的关键问题之一㊂如图10所示,锆合金在中子辐照下容易引发辐照生长[66]㊁辐照硬化[67]和辐照蠕变[68]等㊂这些辐照效应会使锆包壳产生一系列服役安全问题,澄清其微观机制是调控锆合金抗辐照性能的关键㊂图10㊀锆合金的辐照效应:(a)辐照生长[66],(b)辐照硬化[67],(c)辐照蠕变[68]Fig.10㊀The irradiation damage of Zr alloy:(a)irradiation growth[66],(b)irradiation hardening[67],(c)irradiation creep[68]㊀㊀研究表明,辐照生长与<a>型和<c>型位错环密切相关,其中<c>型位错环的形成机理存在争议㊂最新研究[69]揭示了一种<c>型位错环形成的可能机制㊂纯锆在辐照后间隙型位错环的比例高于空位型位错环,额外的空位形成了二维三角形空位型缺陷㊂通过比较三角形空位缺陷与<c>型位错环的尺寸以及两者的能量,发现当三角形空位型缺陷达到临界尺寸后,会塌陷形成能量更低的<c>型位错环㊂氢的存在会降低表面能㊁稳定空位,促进了二维三角形空位型缺陷的形成㊂界面工程是提高材料抗辐照性能的重要方法㊂界面的引入可以加速辐照缺陷的湮灭,降低辐照缺陷的聚集,提高材料的抗辐照性能[70]㊂此外,界面还具有吸收辐照缺陷[71]㊁通过空位泵 [72]机制调控辐照点缺陷分布的作用㊂如何在锆合金设计中引入大量相界面是一个重要的挑战㊂研究者曾采用连续叠轧[73]和磁控溅射[74]技术制备层状锆合金,然而这些方法得到的材料各向异性强㊁加工成本高㊁工艺重复性差㊂近期,研究者采用热机械相变法[75],成功制备出了多级三维纳米层状双相锆铌合金,该合金具备优异的力学性能和抗辐照损伤能力㊂锆合金在服役过程中的辐照蠕变和辐照生长等严重影响其服役安全性㊂通常入堆后的锆材放射性较强,难以进一步细致表征,因此,模拟计算成为了研究和评价新型锆合金抗辐照性能的重要手段[76]㊂在宏观尺度上,一般采用有限元方法进行模拟㊂在介观尺度上,研究者通过VPSC(Visco-Plastic Self-Consistent)方法评估多晶蠕变和生长行为[77,78],通过速率理论[79]模拟缺陷演化并预测辐照硬化㊂在原子尺度上一般采用第一性原理计算和分子动力学模拟的方法研究点缺陷及其复合体的性质㊂最终,通过建立模拟平台实现对锆合金服役性能的跨尺度预测㊂综上所述,加强锆合金辐照损伤机理的研究,有利于促进新型抗辐照锆合金的设计㊂此外,加强多功能测试用263All Rights Reserved.。

The Future of Space Exploration A New Frontier

The Future of Space Exploration A NewFrontierThe future of space exploration is a topic that has captured the imagination of humanity for decades. From the early days of the space race to the recent advancements in technology, the possibilities for exploring the cosmos seem boundless. However, as we look to the future, there are a multitude of factors to consider, including the potential benefits and challenges of space exploration, the ethical implications of venturing into the unknown, and the role of international collaboration in shaping the future of space exploration. One of the most compelling arguments in favor of continued space exploration is the potential for scientific discovery. The universe is a vast and mysterious place, and there is still so much that we have yet to learn about it. By venturing into space, we have the opportunity to expand our understanding of the cosmos, from studying distant planets and stars to gaining insights into the origins of the universe itself. These discoveries have the potential to revolutionize our understanding of the world around us and drive technological advancements that could benefit humanity as a whole. In addition to the scientific benefits, space exploration also holds the promise of economic opportunities. As technology continues to advance, the potential for commercial ventures in space is becoming increasingly feasible. From asteroid mining to space tourism, there are a multitude of ways in which the private sector could capitalize on the resources and opportunities that space has to offer. This could not only drive economic growth but also create new industries and job opportunities for people here on Earth. However, the future of space exploration is not without its challenges. One of the most pressing issues is the environmental impact of space travel. The rockets and spacecraft used to explore space produce a significant amount of pollution, and as we look to expand our presence in space, these emissions are only expected to increase. Finding sustainable and environmentally friendly ways to travel to and from space will be crucial in ensuring that our exploration of the cosmos does not come at the expense of our own planet. Another consideration is the ethical implications of space exploration. As we venture into the unknown,we may encounter new forms of life or come across resources that are of great value. It will be important for us to approach these discoveries with a sense of responsibility and respect, ensuring that we do not exploit or harm other life forms for our own gain. Additionally, we must consider the impact that our presence in space may have on other celestial bodies, such as the potential for contaminating other planets with Earth-based microorganisms. Furthermore, the future of space exploration will undoubtedly be shaped by international collaboration. The challenges and costs associated with space exploration are immense, and no single country can tackle them alone. By working together, nations can pool their resources and expertise to achieve common goals, whether it be establishing a permanent human presence on another planet or conducting large-scale scientific experiments in space. International collaboration will also be crucial in establishing guidelines and regulations for space exploration, ensuring that it is conducted in a safe and responsible manner. In conclusion, the future of space exploration holds great promise, from the potential for scientific discovery to economic opportunities and technological advancements. However, it is important for us to approach this new frontier with a sense of responsibility and mindfulness, considering the ethical implications and environmental impact of our actions. By working together on an international scale, we can ensure that the future of space exploration is one that benefits all of humanity and respects the vast and wondrous cosmos that we are so eager to explore.。

Entropy changes in the clustering of galaxies in a

Vol.3, No.1, 65-68 (2011)doi:10.4236/ns.2011.31009Natural ScienceEntropy changes in the clustering of galaxies in an expanding universeNaseer Iqbal1,2*, Mohammad Shafi Khan1, Tabasum Masood11Department of Physics, University of Kashmir, Srinagar, India; *Corresponding Author:2Interuniversity Centre for Astronomy and Astrophysics, Pune, India.Received 19 October 2010; revised 23 November 2010; accepted 26 November 2010.ABSTRACTIn the present work the approach-thermody- namics and statistical mechanics of gravitating systems is applied to study the entropy change in gravitational clustering of galaxies in an ex-panding universe. We derive analytically the expressions for gravitational entropy in terms of temperature T and average density n of the par-ticles (galaxies) in the given phase space cell. It is found that during the initial stage of cluster-ing of galaxies, the entropy decreases and fi-nally seems to be increasing when the system attains virial equilibrium. The entropy changes are studied for different range of measuring correlation parameter b. We attempt to provide a clearer account of this phenomena. The entropy results for a system consisting of extended mass (non-point mass) particles show a similar behaviour with that of point mass particles clustering gravitationally in an expanding uni-verse.Keywords:Gravitational Clustering; Thermodynamics; Entropy; Cosmology1. INTRODUCTIONGalaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation [1]. They form the densest part of the large scale structure of the uni-verse. In models for the gravitational formation of struc-ture with cold dark matter, the smallest structures col-lapse first and eventually build the largest structures; clusters of galaxies are then formed relatively. The clus-ters themselves are often associated with larger groups called super-clusters. Clusters of galaxies are the most recent and most massive objects to have arisen in the hiearchical structure formation of the universe and the study of clusters tells one about the way galaxies form and evolve. The average density n and the temperature T of a gravitating system discuss some thermal history of cluster formation. For a better larger understanding of this thermal history it is important to study the entropy change resulting during the clustering phenomena be-cause the entropy is the quantity most directly changed by increasing or decreasing thermal energy of intraclus-ter gas. The purpose of the present paper is to show how entropy of the universe changes with time in a system of galaxies clustering under the influence of gravitational interaction.Entropy is a measure of how disorganised a system is. It forms an important part of second law of thermody-namics [2,3]. The concept of entropy is generally not well understood. For erupting stars, colloiding galaxies, collapsing black holes - the cosmos is a surprisingly or-derly place. Supermassive black holes, dark matter and stars are some of the contributors to the overall entropy of the universe. The microscopic explanation of entropy has been challenged both from the experimental and theoretical point of view [11,12]. Entropy is a mathe-matical formula. Standard calculations have shown that the entropy of our universe is dominated by black holes, whose entropy is of the order of their area in planck units [13]. An analysis by Chas Egan of the Australian National University in Canberra indicates that the col-lective entropy of all the supermassive black holes at the centers of galaxies is about 100 times higher than previ-ously calculated. Statistical entropy is logrithmic of the number of microstates consistent with the observed macroscopic properties of a system hence a measure of uncertainty about its precise state. Statistical mechanics explains entropy as the amount of uncertainty which remains about a system after its observable macroscopic properties have been taken into account. For a given set of macroscopic quantities like temperature and volume, the entropy is a function of the probability that the sys-tem is in various quantumn states. The more states avail-able to the system with higher probability, the greater theAll Rights Reserved.N. Iqbal et al. / Natural Science 3 (2011) 65-6866 disorder and thus greater the entropy [2]. In real experi-ments, it is quite difficult to measure the entropy of a system. The technique for doing so is based on the thermodynamic definition of entropy. We discuss the applicability of statistical mechanics and thermodynam-ics for gravitating systems and explain in what sense the entropy change S – S 0 shows a changing behaviour with respect to the measuring correlation parameter b = 0 – 1.2. THERMODYNAMIC DESCRIPTION OF GALAXY CLUSTERSA system of many point particles which interacts by Newtonian gravity is always unstable. The basic insta-bilities which may occur involve the overall contraction (or expansion) of the system, and the formation of clus-ters within the system. The rates and forms of these in-stabilities are governed by the distribution of kinetic and potential energy and the momentum among the particles. For example, a finite spherical system which approxi-mately satisfies the viral theorem, contracts slowlycompared to the crossing time ~ ()12G ρ- due to the evaporation of high energy particles [3] and the lack of equipartition among particles of different masses [4]. We consider here a thermodynamic description for the sys-tem (universe). The universe is considered to be an infi-nite gas in which each gas molecule is treated to be agalaxy. The gravitational force is a binary interaction and as a result a number of particles cluster together. We use the same approximation of binary interaction for our universe (system) consisting of large number of galaxies clustering together under the influence of gravitational force. It is important to mention here that the characteri-zation of this clustering is a problem of current interest. The physical validity of the application of thermody-namics in the clustering of galaxies and galaxy clusters has been discussed on the basis of N-body computer simulation results [5]. Equations of state for internal energy U and pressure P are of the form [6]:(3122NTU =-)b (1) (1NTP V=-)b (2) b defines the measuring correlation parameter and is dimensionless, given by [8]()202,23W nb Gm n T r K Tτξ∞=-=⎰,rdr (3)W is the potential energy and K the kinetic energy ofthe particles in a system. n N V = is the average num-ber density of the system of particles each of mass m, T is the temperature, V the volume, G is the universalgravitational constant. (),,n T r ξ is the two particle correlation function and r is the inter-particle distance. An overall study of (),n T r ξ has already been dis-cussed by [7]. For an ideal gas behaviour b = 0 and for non-ideal gas system b varies between 0 and 1. Previ-ously some workers [7,8] have derived b in the form of:331nT b nT ββ--=+ (4) Eq.4 indicates that b has a specific dependence on the combination 3nT -.3. ENTROPY CALCULATIONSThermodynamics and statistical mechanics have been found to be equal tools in describing entropy of a system. Thermodynamic entropy is a non-conserved state func-tion that is of great importance in science. Historically the concept of entropy evolved in order to explain why some processes are spontaneous and others are not; sys-tems tend to progress in the direction of increasing en-tropy [9]. Following statistical mechanics and the work carried out by [10], the grand canonical partition func-tion is given by()3213212,1!N N N N mkT Z T V V nT N πβ--⎛⎫⎡=+ ⎪⎣Λ⎝⎭⎤⎦(5)where N! is due to the distinguishability of particles. Λrepresents the volume of a phase space cell. N is the number of paricles (galaxies) with point mass approxi-mation. The Helmholtz free energy is given by:ln N A T Z =- (6)Thermodynamic description of entropy can be calcu-lated as:,N VA S T ∂⎛⎫=- ⎪∂⎝⎭ (7)The use of Eq.5 and Eq.6 in Eq.7 gives()3120ln ln 13S S n T b b -⎛⎫-=-- ⎪ ⎪⎝⎭- (8) where S 0 is an arbitary constant. From Eq.4 we write()31bn b T β-=- (9)Using Eq.9, Eq.8 becomes as3203ln S S b bT ⎡⎤-=-+⎢⎣⎦⎥ (10)Again from Eq.4All Rights Reserved.N. Iqbal et al. / Natural Science 3 (2011) 65-68 6767()13221n b T b β-⎡⎤=⎢⎣⎦⎥ (11)with the help of Eq.11, Eq.10 becomes as()011ln ln 1322S S n b b b ⎡-=-+-+⎡⎤⎣⎦⎢⎥⎣⎦⎤ (12) This is the expression for entropy of a system consist-ing of point mass particles, but actually galaxies have extended structures, therefore the point mass concept is only an approximation. For extended mass structures we make use of softening parameter ε whose value is taken between 0.01 and 0.05 (in the units of total radius). Following the same procedure, Eq.8 becomes as()320ln ln 13N S S N T N b Nb V εε⎡⎤-=---⎢⎥⎣⎦(13)For extended structures of galaxies, Eq.4 gets modi-fied to()()331nT R b nT R εβαεβαε--=+ (14)where α is a constant, R is the radius of a cell in a phase space in which number of particles (galaxies) is N and volume is V . The relation between b and b ε is given by: ()11b b b εαα=+- (15) b ε represents the correlation energy for extended mass particles clustering gravitationally in an expanding uni-verse. The above Eq.10 and Eq.12 take the form respec-tively as;()()3203ln 111bT b S S b b ααα⎡⎤⎢⎥-=-+⎢⎥+-+-⎢⎥⎣⎦1 (16) ()()()120113ln ln 2111b b b S S n b b ααα⎡⎤-⎡⎤⎢⎥⎣⎦-=-++⎢⎥+-+-⎢⎥⎣⎦1 (17)where2R R εεεα⎛⎫⎛⎫=⎪ ⎪⎝⎭⎝⎭(18)If ε = 0, α = 1 the entropy equations for extended mass galaxies are exactly same with that of a system of point mass galaxies approximation. Eq.10, Eq.12, Eq.16and Eq.17 are used here to study the entropy changes inthe cosmological many body problem. Various entropy change results S – S 0 for both the point mass approxima-tion and of extended mass approximation of particles (galaxies) are shown in (Figures 1and2). The resultshave been calculated analytically for different values ofFigure 1. (Color online) Comparison of isothermal entropy changes for non-point and point mass particles (galaxies) for an infinite gravitating system as a function of average relative temperature T and the parameter b . For non-point mass ε = 0.03 and R = 0.06 (left panel), ε = 0.04 and R = 0.04 (right panel).All Rights Reserved.N. Iqbal et al. / Natural Science 3 (2011) 65-68 68Figure 2. (Color online) Comparison of equi-density entropy changes for non-point and point mass particles (galaxies) for an infinite gravitating system as a function of average relative density n and the parameter b. For non-point mass ε= 0.03 and R = 0.04.R (cell size) corresponding to different values of soften-ing parameter ε. We study the variations of entropy changes S – S0with the changing parameter b for differ-ent values of n and T. Some graphical variations for S – S0with b for different values of n = 0, 1, 100 and aver-age temperature T = 1, 10 and 100 and by fixing value of cell size R = 0.04 and 0.06 are shown. The graphical analysis can be repeated for different values of R and by fixing values of εfor different sets like 0.04 and 0.05. From both the figures shown in 1 and 2, the dashed line represents variation for point mass particles and the solid line represents variation for extended (non-point mass) particles (galaxies) clustering together. It has been ob-served that the nature of the variation remains more or less same except with some minor difference.4. RESULTSThe formula for entropy calculated in this paper has provided a convenient way to study the entropy changes in gravitational galaxy clusters in an expanding universe. Gravity changes things that we have witnessed in this research. Clustering of galaxies in an expanding universe, which is like that of a self gravitating gas increases the gases volume which increases the entropy, but it also increases the potential energy and thus decreases the kinetic energy as particles must work against the attrac-tive gravitational field. So we expect expanding gases to cool down, and therefore there is a probability that the entropy has to decrease which gets confirmed from our theoretical calculations as shown in Figures 1 and 2. Entropy has remained an important contributor to our understanding in cosmology. Everything from gravita-tional clustering to supernova are contributors to entropy budget of the universe. A new calculation and study of entropy results given by Eqs.10, 12, 16 and 17 shows that the entropy of the universe decreases first with the clustering rate of the particles and then gradually in-creases as the system attains viral equilibrium. The gravitational entropy in this paper furthermore suggests that the universe is different than scientists had thought.5. ACKNOWLEDGEMENTSWe are thankful to Interuniversity centre for Astronomy and Astro-physics Pune India for providing a warm hospitality and facilities during the course of this work.REFERENCES[1]Voit, G.M. (2005) Tracing cosmic evolution with clus-ters of galaxies. Reviews of Modern Physics, 77, 207- 248.[2]Rief, F. (1965)Fundamentals of statistical and thermalphysics. McGraw-Hill, Tokyo.[3]Spitzer, L. and Saslaw, W.C. (1966) On the evolution ofgalactic nuclei. Astrophysical Journal, 143, 400-420.doi:10.1086/148523[4]Saslaw, W.C. and De Youngs, D.S. (1971) On the equi-partition in galactic nuclei and gravitating systems. As-trophysical Journal, 170, 423-429.doi:10.1086/151229[5]Itoh, M., Inagaki, S. and Saslaw, W.C. (1993) Gravita-tional clustering of galaxies. Astrophysical Journal, 403,476-496.doi:10.1086/172219[6]Hill, T.L. (1956) Statistical mechanics: Principles andstatistical applications. McGraw-Hill, New York.[7]Iqbal, N., Ahmad, F. and Khan, M.S. (2006) Gravita-tional clustering of galaxies in an expanding universe.Journal of Astronomy and Astrophysics, 27, 373-379.doi:10.1007/BF02709363[8]Saslaw, W.C. and Hamilton, A.J.S. (1984) Thermody-namics and galaxy clustering. Astrophysical Journal, 276, 13-25.doi:10.1086/161589[9]Mcquarrie, D.A. and Simon, J.D. (1997) Physical chem-istry: A molecular approach. University Science Books,Sausalito.[10]Ahmad, F, Saslaw, W.C. and Bhat, N.I. (2002) Statisticalmechanics of cosmological many body problem. Astro-physical Journal, 571, 576-584.doi:10.1086/340095[11]Freud, P.G. (1970) Physics: A Contemporary Perspective.Taylor and Francis Group.[12]Khinchin, A.I. (1949) Mathamatical Foundation of statis-tical mechanics. Dover Publications, New York.[13]Frampton, P., Stephen, D.H., Kephar, T.W. and Reeb, D.(2009) Classical Quantum Gravity. 26, 145005.doi:10.1088/0264-9381/26/14/145005All Rights Reserved.。

(完整)高职高专英语词汇表

《高职高专英语》大纲词汇表（部分）说明：本词汇表依据教育部高等教育司《高职高专教育英语课程教学基本要求（试行）》拟定，其中有*号者为A级词汇，无标记的为入学需要掌握的词汇和B级词汇。

abandon* v. 放弃,遗弃,沉溺absolute* a. 绝对的,完全的absorb* v. 吸收,使全神贯注abstract* n.摘要a.抽象的v.摘要abundant* a. 丰富的,充裕的access* n. 通路,进入,使用之权accommodation* n. 住处,膳宿accompany* v. 陪伴,带有accomplish* v. 完成account n.帐目,报告,估计v. 叙述,解释accumulate* v. 积聚,堆积accurate* a. 准确的,精确的accuse* v. 责备,控告acknowledge* v. 承认,答谢,告知收到acquire* v. 获得,取得,学到actually ad. 实际上additional a. 附加的,另外的adequate* a. 足够的,适当的,能胜任的admire*v. 钦佩,羡慕,赞赏admission* n.许可,入会费,承认advance n.v. 前进agency* n. 代理,代理处agenda* n. 议事日程agent* n.代理人,代理商,特工airline n. 航线；航空公司alcohol* n. 酒精allowance* n. 津贴alphabet* n. 字母表alter* v 改变alternative n.选择之物a.二者选其一ambassador* n 大使ambition* n 雄心；远大目标ambitious* a雄心勃勃的amend* v修正，修订amuse* v逗乐；提供娱乐ancestor* n 祖先；先驱者anniversary* n 周年（纪念）annoy* v使恼怒；使烦恼annual a 每年的；n年刊anticipate* v预期；希望anxiety* n忧虑；渴望anxious a焦虑的；急切的apartment n公寓apparent* a 表面上的；明显的appeal to v呼吁,恳请,吸引,上诉appearance* n出现；外貌appendix* n附录；附属物appetite* n食欲,胃口;欲望,爱好appetizing*a开胃的;刺激欲望的applause* v鼓掌；欢呼appliance* n电器；装备applicant* n请求（申请）者application n申请（表）；应用appoint* v任命;约定(时间地点) appreciate v重视，欣赏；领会；为……表示感谢approach* v靠近；n接近；途径；方法appropriate* a 适当的approval* n赞成，同意；批准approve* v赞成，同意；批准arbitration* n仲裁，公断arise v出现；起源于arouse* v引起；唤醒artificial* a人工的；假的aside a在旁边，到一边aspect n方面assess* v评估，评价assign* v指派；布置；指定assignment* n(指定的)任务;指派；分配assist* n协助assistant n助手a副的;助理的associate* v把…联系在一起；交往n伙伴，合伙人；a副的association* n协会，社团；联合；联想assume* v假定；承担astonish* v使惊讶atmosphere n 大气；气氛attach v贴；使附属；使依恋attend v出席；照料；专心于attendant* n服务员a陪同的authority n[pl.]官方，当局；当权者；权力，权威authorize* v授权，委任auto n汽车automatic a自动的automobile* n汽车available a可利用的,可得到的；可取得联系的avenue* n林荫道；大街await*awake a醒着的v唤醒awful* a 可怕的；极度的awkward* a笨拙的；尴尬的，棘手的bachelor* n单身汉；学士balance* v使平衡；称n天平；均衡；差额ball n舞会banquet* n宴会bare a赤裸的，不戴帽的；光秃秃的；勉强的v露出，暴露bargain v讨价还价n交易；特价商品barrier* n障碍（物）battery* n电池（组）bear v忍受；负担；结，生behalf* n利益behave* v(机器)运转；举止behavior n(机器)运转；举止beneath prep在...下面ad在下面berth* n卧铺；泊位，停泊处bid* n/v 出价，投标bind v捆绑（扎）blend* v混合n混合物board n板；董事会，委员会；伙食v上（车）bold a勇敢的；冒失的；粗体的bond* n联结；公债，债券bonus* n奖金；额外酬金bore* v使厌烦；钻，凿，挖n令人讨厌的人（事）bound* a一定的；有义务的；开往…的v跳跃，弹回boundary* n分界线；边界brilliant* a光辉灿烂的；卓越杰出的brochure* n小册子broker* n经纪人budget* v/n预算bulletin* n告示bureau* n局campaign* n运动；战役candidate n候选人；报考者；申请求职者capacity* n容量，容积；能力capture* v/n捕获cashier* n出纳员cast* v投；铸造casual* a随便的；偶然的catalogue* n目录（册）；v编入目录；编目分类cease* v/n 停止centigrade* a/n摄氏（的）ceremony n典礼；礼节certificate n证（明）书；执照characteristic* a特有的n特性charge v索价；控告；充电n收费；控告；充电，电荷chase* v/n追逐check v检查；制止n检查；支票Christian* n基督教徒；a基督教的circuit* n电路；环行circumstance* n环境,条件,情况claim v宣称；提出要求n宣称；索赔clarify* v澄清；阐明classic* n[pl]杰作a一流的classical a古典的，经典的classify* v分类clause n条款clockwise* a/ad顺时针coach v指导n长途汽车；铁路旅客车厢colleague* n同事collection* n收藏品；收集collective* a/n 集体column* n柱；栏；专栏combination* n结合；化合（物）comment n/v 注解；评论commerce n商业；贸易commercial* n电视广告a商业的commission* n授权，委托；佣金，回扣；委员会commit* v犯，干；承诺commodity* n商品commute* n通勤;定期往返;变换compact* a紧密；坚定；简洁的companion n同伴，伴侣comparable* a可相比；敌得上compatible* a相容；谐调；一致compensate*v赔偿；报酬；弥补competent* a有能力；胜任competitive* a竞争complaint* n抱怨；怨言；控诉complex* a综合；复杂n综合体complicated* a复杂；难懂component* n成分；部件compose v构成；创作，谱曲composition* n成分；作文；乐曲；compound* a复合n化合物comprehension n理解（力）comprise*v包含,由…组成,构成compromise* n妥协；折中办法concentrate v集中；集合；浓缩concern n关心;关联v关心;涉及concerning prep关于conduct n行为v处理；传conductor n导体;指挥;列车员confess* v 坦白；承认confidential* a机密confine* v使受到限制confirm* v证实；确认；批准conflict* v/n冲突；抵触conform* v一致，符合confront* v面对；遭遇；对抗confuse v使混乱；混淆congress* n代表大会；国会，议会consequence n 结果，后果consequently ad因此conservative* a/n保守的（人）conserve* v保持considerable a相当大;值得考虑considerate a 体谅；考虑周到consist v组成；在于constraint* n强制;拘束;压迫感consul* n. 领事consulate* n. 领事馆consult v.商讨,向...请教,查阅consultant* n. 顾问consume*v. 消耗,花费consumption* n. 消费（量）content n[pl]内容,目录;含量a满意的contest* v/n竞争,比赛context* n上下文;前后关系continual a连续的continuous a连续不断的contract n合同;v订合同;使收缩contradict* v同…矛盾(抵触)contrary a相反的;n相反(事物)contrast* v/n对比contribute* v捐献,贡献;投稿conversion* n转变(化,换)convert* v转变(化)convey* v运(输)送;传达(送)convince v使确信(信服)cooperate v合作;配合coordinate* v调节,协调copyright* n版权;著作权a有版权的corporation* n公司correspond v与…一致;相当(类似) correspondence* n通信,函电;相当correspondent* n通信者;通讯员;有业务往来者corresponding* a相应的;一致的costly a昂贵;代价高的council* n委员会;理事会counter n柜台;记数器;v反对courteous* a有礼貌的craft* n手艺;船;航天器creature* n生物;人credit* n信用贷款;信用;荣誉;赞扬;功劳;学分v记入贷方crew* n全体船(机组)人员criminal* n罪犯;a刑事的crisis n危机;决定性时刻critical a批评的;关键性的crucial* a极其重要的;严重的crude* a简陋的;天然的;粗俗的crystal* n水晶;a清澈透明的;晶体的currency* n通货;货币;流通;通用current n流;电流;a当前的;流行的cursor* n光标curve* n曲/弧线;v(使)弯曲damp* a潮湿的;n潮湿dash* v/n飞奔;猛掷;data* n数据;资料database 数据库deadline 截止时间；界限dealer* 商人；贩子debate* 辩论;讨论decay* 腐烂;衰落deceive* 欺骗decrease 减少(小)defence / defense* 击败;使落空defend 保卫;为…辩护definite 明确的;肯定的delegate* 代表;委员/ //授权;委托;委派delete* 取消;删除deliberately* 深思熟虑地;有目的地delicate 纤细的;清秀的;鲜美的;优美的;易碎的;纤弱的;微妙的;棘手的;灵敏的;精密的delight 使高兴//快乐;令人高兴的东西或人democracy* 民主(国家)demonstrate* 论证;演示;示威density* 密集;稠密;密度deny 拒绝给予(要求);否认department 部门;系科departure 出发;离开dependent* 依靠的deposit* 使沉淀;存放;储蓄;交押金//沉积物;定金;押金depress* 使沮丧;降低derive* 取得;追溯…的起源deserve* 应受;值得desirable* 值得向往的;称心的despair* 绝望//绝望despite 不管,尽管dessert* 甜点destination* 目的地;目标destruction* 破坏;消灭detect 察觉;侦察determination* 决心determine 决心;查明;决定device 装置;设备;器具devote 将…奉献;把…专用于diagnose* 诊断diagram* 图表;简图dialect* 方言differ 不同;与…意见不同digest* 消化//摘要digital* 数字的;用数字显示的dim* 昏暗的;朦胧的dimension* 尺寸,长(宽,厚,深)度;面积,大小,规模dine 就餐diplomat* 外交官direct 笔直的;率直的;直接(地)//针对;指示;指导,管理direction 方向(位);用法说明director 指导者,主管;董事;导演disaster* 灾难discharge* 离开;放出;卸货//释放;排除discipline* 纪律;训练//训导;惩罚disclose* 揭开;揭发;露出disconnect* 断绝(开);使脱离discount* 折扣discourage* 使泄气disgust* 厌恶//使厌恶disgusting* 令人厌恶的dismiss 免职,开除;解散disorder 杂乱;骚乱;失调dispose* 去掉,消除;排列;安排dispute* 争论//争吵distinct* 截然不同的;清楚的,明白的distinction* 差别;区分distinguish* 区别;分清distort* 歪曲;使变形district* (地)区,行政区divide 分;分配;隔开;除divorce* 离婚;分离domestic*本国的;家用的;驯养的dominate* 支配;统治;管辖draft* 草稿(案)//起草dramatic* 引人注目的,给人深刻印象的;戏剧性的//表演drift (使)漂流//漂流duplicate* 完全相同的;副本的//加-倍,复制//副本;相同的东西durable* 持久的,耐用的duration* 持续;持久dynamic(al)* 动力的;力学的;充满活力的earnest* 认真的;诚恳的ease 容易;安逸,舒适//缓和;减轻echo* 回声//共鸣economic 经济(学)的economical 节约的effective 有效的efficient 效率高的;有能力的elaborate* 复杂的;精心制作的//详尽阐述,发挥;变得复杂elderly 年长的election* 选举electric 电(动)的electricity 电electronic* 电子的element 基本组成部分;要素;元素elementary* 基本的;初级的elevator* 电梯eliminate* 消除;淘汰embarrass* 使窘迫(为难) embassy* 大使馆emerge* 出现;显露;被知道emergency*紧急情况;不测事件emotion 情感(绪)emperor* 皇帝emphasis* 强调;重点emphasize(-se) 强调;着重empire* 帝国enclose 围住;封入;附上endure* 忍受;持久engage* (使)从事与/忙于;吸引;占用;雇用;使订婚engineering 工程(学)enhance* 增加;提高enormous* 巨大的ensure 保证,担保enterprise 企业entertain 使欢乐;招待;考虑enthusiasm* 热情entry 进入;入口;人(物),条目envelope 信封equivalent* 相等的;等值的//相等物era* 时代error 误差essential 必不可少的;本质的//本质,要点estate* 财产;地产estimate v/n估计;评价evaluate* 估量;评价;鉴定eventually 终于,最后evidence 根据,证据evident* 明显的,明白的evil* 邪恶;祸害//邪恶的,坏的evolution* 演变,进化;进展,发展exact 确切的,精确的examine 检查,调查;考察exceed* 超过exception* 例外excess* 超越;过量//过量的excessive* 过量的,过度的exchange v/n交换,调度;交谈exclude* 把…排除在外,排斥execute* 处死;实施executive* 执行官,行政官//执行的exert* 运用,行使;用,尽exhaust* 使精疲力竭;耗尽//排气装置;废气exhibit 展出//展品existence 存在;生存expectation* 期待;预料expenditure* 消费;费用expert 专家//内行的export 出口,输出//出口(物)explanation 解释,说明explode (使)爆炸(发)exploit* 剥削;利用;开发(采)explore* 探险;探索expose (使)暴露于exposure* 暴露,曝光express 陈述;体现//快车extend 延长;扩大;给予extensive* 广阔的extent 程度;范围external 外部的extra额外的事物;另外的收费//额外的;特别的extraordinary* 非常的,非凡的,奇异的extreme 极度的;尽头的//极端facility 设备;便利,容易factor 因素faculty* 才能;(大学)系,院;全体人员fade* (使)褪色;衰退;变微弱failure 失败(的人或事);没做到,不履行;失灵,故障faint 微弱的,微小的//晕倒,昏阙fairly 相当;公正地faithfully 忠诚地;如实地familiar 熟悉的;常见的,日常用的fancy 想象;猜想;喜爱//空想出来的;花俏的;奇特的//想象力,;幻想;爱好,迷恋fare (车船)费fatal* 命运的的,命中注定的,致命的fatigue* 疲劳favor 好感;恩惠,善事//赞同;偏袒favorable 有利的;顺利的;称赞的fax / facsimile 传真feasible* 可行的,可用的feature 特征;相貌feedback* 反馈fence* 栅栏,篱笆festive* 节日的,欢乐的fiber / fibre* 纤维fierce 凶猛的;狂热的;猛烈的figure 数字;轮廓;人物;体型,风姿;插图filter* 过滤//过滤器finance* 财政,金融financial* 财政的,金融的fine 罚金//处…以罚金//美好的,优秀的;纤细的;精制的;晴朗的fit (使)适合;(使)配合;安装//适合的;强健的fix 固定;安装;决定;确定;修理;安排flavour* 风味flexible 易弯曲的;柔韧的;灵活的forbid* 禁止format* 板式//格式化formula* 公式forth 向前;往外fortnight* 两星期fortunate* 幸运的;侥幸的fortune 运气;财产foundation* 基础;地基;建立;基金会;根据fountain* 喷泉framework* 框架;体系frequency 频率；频繁frustrate*使受挫；破坏；使挫败fuel* 燃料//加燃料fulfil(l) 满足；实现function 起作用；行使职责//功能；职责fund 资金；基金；储备fundamental* 基本的//基本原则furthermore 而且gain V(钟表)走快；获得；V/N增加；得益gap 缺口；间隙；差距garage 车库；加油站gay 快乐的；色彩鲜艳的gene* 遗传基因generate* 使产生；引起generation 一代；产生generous* 慷慨的；宽厚的genius* 天才；天才人物gentle 和蔼的；轻柔的；不陡的genuine 真心的；坦诚的geometry* 几何（学）gesture 姿势；姿态；表示gift 天赋；礼物glorious* 壮丽的；光荣的glory 光荣；荣誉glow 广亮//发光govern 统治；支配graceful 优雅的；得体的gradual* 逐渐的grand*宏伟的；重大的；豪华的grant 拨款//授予，准予graph* 图表graphic* 图的；生动的grateful 感激的gratitude* 感激grave 坟墓//庄重的；严重的greet 问候；接受；呈现在…前grocer* 食品杂货商gross* 总的；严重的guidance 指导，领导guide 导游；指南//指导；给…导游gym(-nasium)* 体育馆；健身房hardware 五金；硬件hardship 艰难heading* 标题headline 大字标题；新闻提要headquarters* 总部；指挥部hence* 因此；今后heroic* 英雄的；英勇的highlight* 以强光照射；强调//最明亮的部分；最重要部分hit 成功而风行一时的事物hi-tech* 高新技术honorable* 诚实的；尊敬的horizon 地平线；眼界，见识horsepower* 马力hospitable* 好客的host 东道主;目主持人；一大群hostile* 敌对的；不友善的house 给..房子住//商号however 不管怎样//然而humble* 谦逊的；低下的；恭顺的identical* 相同的；相等的identification* 识别；身份identify 认出；认为…等同于idle* 虚度//空闲的；懒散的illustrate*阐明；给…作插图说明illustration* 说明；插图image 像；映像imitation* 模仿immediate 立即的；直接的；最接近的immigrant* 移民；侨民immigrate* （从国外）移来的implication* 含义；暗示imply 暗示；意味着import 进口商品//进口；输入impose 把…强加于；征税impress 使铭记；压印improvement 改进；改进之处incident* 发生的事；事件incline* （使）倾斜（倾向于）//斜坡，斜面inclusive* 包括（一切）的index* 索引；指标//为…编索引indicate* 指示；表明individual*个别的;特的//个人induce* 说服；劝诱industrial 工业的industry 勤奋；工业inevitable* 不可避免的infect* 传染；感染infectious* 感染的infer* 推论inference* 推论inferior* 低下的；下级的infinite* 无限的inform 告发；通知initial* 开始的//首字母initiative* 主动性；首创精神injection* 注射injury 伤害；受伤处inner* 内心的；内部的innocent* 无罪的；幼稚的；无害的input 输入；投入的资金inquiry/enquiry 打听；调查insect* （昆）虫insert* 插入；刊登//嵌入物insight* 洞察力，观点inspection* 检查inspire* 鼓舞；激起；给灵感install* 安装installment* 一期付款instance* 例子instant 即刻，瞬间//立即的；紧急的；速溶的instinct* 本能；直觉institute 学会；研究所；学院institution*设立;公共机构；学会instruct 教；命令；通知instruction 教学;指示；用法说明instrument 仪器；工具；乐器insult* v/n 侮辱insurance* 保险（金，费）insure 给保险；保证integrate*使一体化；（使）综合intellectual* 知识分子//智力的intelligence* 智力；情报intelligent* 明智的intense 强烈的；热情的interaction* 相互作用interest 利害关系；利率//引起兴趣interference* 干涉；妨碍interior* 内部的；内地的//内部（地）intermediate* 中间的interpretation* 解释；口译interrupt 打断；中止interval* 间隔；工间休息investigate* 调查investigation*调查研究investment*投资（额）invisible*无形的invoice*发票；发货单involve牵涉；使卷入；包含irrevocable*无法挽回的；不可撤销的isolate使隔离issue颁布，出版，发布／／问题；发行，期号item条，项目；一则itinerary*旅行指南jam v/n拥挤；堵塞；卡住jeans牛仔裤joint 结合处；关节//合资（联合）的journal 杂志；期刊；日志journalist 新闻记者justice 正义；司法justify 证明…正当（有理，正确）；为…辩护karaoke* 卡拉OKlabel*标签//贴标签于，把…称为labor 劳工；劳动laboratory/lab 实验室lag* V/N 落后lane* 胡同；车道launch* 发射；使（船）下水；发动，发起laundry洗衣房;待(已)洗的衣物layout* N安排；布局；陈设lead 铅leaf 薄金属片leak* 渗漏;泄露//漏洞；露出量lean* 倾斜；靠；依靠leap* V/N跳；飞跃learning 学问；学习leisure 闲暇；安逸length 长（度）；一段level 水平面;等级//(水)平的liable* 易于；可能的liberation* 解放liberty* 自由；许可；冒昧licens(c)e* 许可；执照//批准；发许可证light 照亮//轻快的；愉快的litre/liter* 升load* 装(载,货)//负荷;装载量loan* 贷款；暂借//借出local 地方的;当地的；局部的locate 找出;查明;把…设置在log* 原木；木料logic* 逻辑（学，性）logical* （符合）逻辑的loose 松的lorry* 卡车lower 降下；减弱//下游的magic* 魔术（法）；有魔力的magnificent* 壮丽（宏伟）的maintain* 维持；保养；主张maintenance* 维持；保养；主张majority 大多数mall 购物中心management* 管理manual* 手工的；体力的//手册manufacture 制造//制造业；产品margin* 页边空白；边缘//余地marvelous* 奇迹般的；惊人的mask* 面具；口罩；伪装//戴面具；掩饰；伪装mass 众多；团；群众；质量mature* 成熟（成年人）的//（使）成熟maximize* 使最大化；充分重视maximum* 最大限度；顶点//最高（大）的mean 自私的；卑鄙的means 方法mechanical 机械的；力学的；呆板的；手工的mechanism* 机械装置；机制medium* 中等的；适中的//媒介；中间；适中memo(-randum)* 备忘录memorial* 纪念的//纪念堂（碑，仪式）mental 精神的；智力的merchant* 商人；零售商mercy* 慈悲；宽容mere 纯粹的merely* 仅仅merit* 优点microscope* 显微镜military 军事（用）的minimum* 最低的//最低限度；最少量minister* 部长；大臣minor* 较小的；较次要的minority* 少数（派，民族）minus* 减（去）//负的；减去的miracle 奇迹；令人惊奇的人miserable* 痛苦/悲惨/可怜的mission* 使命；任务；代表团mixture 混合（物）mode* 方式；样式moderate* 温和/稳健/有节制/适度的modest 适中/不过分的modification*修改；修饰；减少modify* 缓和；修改；修饰moisture* 潮湿；湿气monitor 监听（检测）器//监听；监测monument* 纪念碑mood* 心情；语气moral* 道德（上）的；有道德的//寓意mortgage* 抵押贷款motion* 运动;手势;提议//打手势;示意motivate* 激起;激发积极性motive* 动机;目的mount 登上;安放//峰multiple* 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小册子panel* 专门小组；面，板；控制仪，仪表盘parallel* 可相比拟的事物；相似处；平行线；平行面parameter* 参数parcel* 包裹parliament* 议会；国会participant* 参加（考）者participate 参与partly 在一定程度上；不完全地；部分地passage 通道；经过；消逝passion* 激情；酷暑passive 消极的；被动的passport 护照paste* 浆糊//粘贴Patternｎ．型、模式、样式、图案、花样Pauseｖ／ｎ.暂停、中止Peculiarａ奇怪的、古怪的特殊的、独特的Perceiveｖ察觉、感知认识到、意识到、理解Perfectａ完美的，完满的,完全的十足的ｖ使完美，改善Performanceｎ演出，表演履行，执行，表现permanent*ａ永久（性）的，固定的permissible*ａ可允许的，可原谅的permission*ｎ允许，许可persist*ｖ坚持不懈，执意持续，存留Personalａ个人的，私人的，亲自的Personnelｎ人员，员工Petrolｎ汽油phase*ｎ阶段，时期，面，方面，phenomenonｎ现象，迹象philosopherｎ哲学家philosophy*ｎ哲学，主旨physicalａ身体的，物理的，物质的，有形的，自然的pioneer* ｎ先驱者，开拓者platform*ｎ台平台，讲台，站台plentiful*ａ丰富的，多的plot*ｎ计划，密谋，情节ｖ绘制，标绘，计划Plusａ加号的，正的prep加，加上poll*ｎ投票，计数，民意测验Poolｎ水池，联营，合资经营ｖ联营Popｎ流行音乐，ｖ突然出现，发生porcelain*ｎ瓷器portable*ａ便于携带的，轻便的，手提式的portionｎ位置，职位，职务，姿态，见解，立场*poseｎ姿势ｖ摆姿势*positiveａ确实的，确信的，明确的，肯定的，断然的，正极的possessｖ占有，拥有possibilityｖ可能性postage*ｎ邮资poster*ｎ海报，标语postponeｖ推迟，延期potential*ａ潜在的，可能的ｎ潜力，潜能pourｖ倒，倾泻，流出povertyｎ贫穷，贫困powerｎ权力，政权，力量，能力，功率，动力，乘方，电力practical 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ad立刻，不久，简短地，简慢地sightseeing*ｎ观光，游览significance*ｎ意思，含义，重要性，significantａ相当数量的，不可忽略的，重要的意义重大的，意味深长的simultaneous*ａ同时的singleａ单独的，单人的，单一，单个的，未婚的，独身的singular*ａ单数的，非凡的，突出的，独一的，唯一的siteｎ场所，定点sketch*ｎ素描，速写，略图，草图，概述，纲要ｖ素描，速写，画草图slice*ｎ薄片，切片，部分ｖ把……切成片slide*ｖ使滑动，使滑行ｎ滑道，幻灯片，滑动slope*ｎ斜坡，斜面，倾斜，斜度ｖ使倾斜smartａ漂亮的，时髦的，聪明的，精明的smuggle*ｖ走私snack*ｎ小吃，快餐soleａ单独的，唯一的，仅有的solutionｎ解答，解决，溶解，溶液somewhat 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The composition of the Earth

1. Introduction An accurate and precise model of the chemical and isotopic composition of the Earth can yield much information regarding its accretion processes, and global-scale differentiation processes, including: core segregation, possible mineral fractionation in a primordial magma ocean and crust-mantle differentiation. With such a model we can also constrain compositional estimates for present-day reservoirs in the Silicate Earth and thus provide insights into their evolution. (The terms Silicate Earth and Primitive Mantle are synonymous.) There are three main approaches which have been used to model the composition of the Earth: ( 1) using the seismic profile of the core and mantle and their interpretation; (2) comparing the compositional systematics of primitive meteorites and the solar photosphere to constrain the solar nebula composition and from this estimate the composition of the inner rocky planets; and ( 3 ) using chemical and petrological models of peridotite-basalt melting relations (i.e. the pyrolite model). The seismic velocity structure of the Earth, in combination with mineral physics data for phases at the appropriate pressures and temperatures, provide important information about the average density and from this the bulk composition of the crust, mantle and core. These data yield basic insights into the gross compositional characteristics of these regions, but cannot be used to constrain the minor- and trace-element composition of the Earth. Compositional models based on primitive meteorites relates elemental abundances in the bulk Earth to those observed in chondritic meteorites in general, but particularly the CI carbonaceous chondrites, the most primitive of the chondritic meteorites. These meteorites are free of chondrules, possess the highest abundances of the moderately-volatile and volatile elements rela-

郯庐断裂带北段构造特征及构造演化序列

郯庐断裂带北段构造特征及构造演化序列孙晓猛;王书琴;王英德;杜继宇;许强伟【摘要】根据大量野外地质调查和盆地地震资料分析,认为郯庐断裂北段在中-新生代发生多期不同性质的活动,形成各具特色的构造变形现象.密山县知一镇敦密断裂韧性剪切带具有左旋走滑特征,其中黑云母~(40)Ar/~(36)Ar-~(39)At/~(36)Ar等时线年龄为161±3Ma,是郯庐断裂带被利用发生第二期左旋走滑运动并向北扩展到中国东北-俄罗斯远东地区的产物.四平市叶赫乡佳伊断裂带中负花状断裂形成于早白垩世早中期,是郯庐断裂北段在早白垩世遭受左旋走滑.拉张作用的典型代表.四平市石岭镇佳伊断裂大型走滑-逆冲断褶带、桦甸县敦密断裂"逆地堑"、沈阳-哈尔滨逆冲断裂形成于晚白垩世嫩江运动-晚白垩世末期,这一时期脆性右旋走滑-逆冲事件规模大,影响范围广,导致整个郯庐断裂北段遭受到强烈改造.佳伊断裂带和敦密断裂带中古近纪盆地在横剖面上呈不对称地堑,并且不对称地堑沿断裂带走向发生断、超方向左右变位,是郯庐断裂带北段在古近纪时受右旋走滑、伸展双重机制控制的产物.根据郯庐断裂带北段中-新生代不同地质时期变形特征,建立了郯庐断裂北段构造演化序列.即郯庐断裂北段构造演化分为左旋韧性剪切(J_2末期)、左旋张扭(K_1早中期)、右旋压扭(K_2晚期-末期)、右旋走滑断陷(E)和构造反转(E_3末期)五个阶段.其演化历史主要受控于环太平洋构造域的构造作用.【期刊名称】《岩石学报》【年(卷),期】2010(026)001【总页数】12页(P165-176)【关键词】郯庐断裂;敦化.密山断裂;佳木斯-伊通断裂;构造特征;构造演化序列【作者】孙晓猛;王书琴;王英德;杜继宇;许强伟【作者单位】吉林大学地球科学学院,长春,130026;吉林大学地球科学学院,长春,130026;吉林大学地球科学学院,长春,130026;吉林大学地球科学学院,长春,130026;吉林大学地球科学学院,长春,130026【正文语种】中文【中图分类】P542.3;P597.3半个世纪以来，郯庐断裂构造特征及其演化一直是中外地质学家关注的焦点问题之一，也是东北亚大陆边缘中、新生代构造演化及其地球动力学机制研究的关键科学问题。

2022年考研考博-考博英语-湘潭大学考试预测题精选专练VII(附带答案)卷10

2022年考研考博-考博英语-湘潭大学考试预测题精选专练VII（附带答案）第1套一.综合题(共25题)1.单选题Lines of latitude run horizontally and are parallel to the Equator and lines of longitude run vertically. They（）at the North and South Poles.问题1选项A.convergeB.convokeC.convoyD.convulse【答案】A【解析】动词词义辨析。

根据句意‘纬线水平平行于赤道和经线相垂直。

它们在南北两极聚集。

’可知这里是说经线和纬线的位置，根据常识可知经线和纬线相互垂直，在南极和北极两个地方是聚集的，A选项converge"聚集，靠拢”；B选项convoke“召集”； C选项convoy“护送”；D选项convulse“震撼”。

根据句意确定A选项正确。

2.翻译题Like waistlines in many prosperous countries, cell phones are going XXL and some of their owners are struggling to tuck them in.Jeremy Roche, 47 years old, owns a Samsung Galaxy Note II phone that is about 75% larger than the original Apple Inc. iPhone, and roughly the size and heft of an extra-large Hershey’s chocolate bar, with about an inch nibbled off the end. It “did feel weird” at first to hold his big phone to his head for calls, he says, but now he loves his ample screen. After years of evolution from brick-size monstrosities into slim pocket devices, cell phones are going in reverse. South Korea's Samsung Electronics Co. is credited —or blamed 一 with bringing big phones back into the mainstream with devices like the original 5.3-inch Note, introduced outside the U.S. in late 2011.Some tech reviewers at the time derided the big phone as “silly”，and “a phone designed for giants.” But sales boomed, and other makers have followed with still-bigger “phablets”, as techiesarc beginning to call them—a cross between a phone and a tablet.Fares Fay ad, a 39-year-old consultant in Dubai, says he used to think a 3.5-inch cell phone screen was just right, until he tried the iPhone 5, which has a 4-inch screen. “I don’t believe I can go back to the slightly smaller screen,” Mr. Fay ad says,Some ergonomics experts wor ry lame phones could pose an injury risk. “As the stretch to reach all areas of the screen increases, we might start to see more serious repetitive stress injuries --- likely to the thumbs --- in larger touch-screen devices”, says Anthony Andre, a professor of human factors and ergonomics at San Jose State University.【答案】就像许多富裕国家居民的腰围一样，如今手机的尺寸也在逐渐增大，一些手机用户在费尽心思想把它们塞进自己的兜里。

软件工程术语表

软件工程术语表软件工程术语表目录1. 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关于Midjourney的一千个关键词

8建筑描述：高耸的摩天大楼Architectural descriptions: towering skyscrapers废弃的工厂abandoned factories破败的公寓楼dilapidated apartment buildings荒废的仓库deserted warehouses未来主义建筑futuristic buildings高达100层的摩天大楼skyscrapers up to 100 storeys high废弃的化工厂abandoned chemical plants破旧的公寓楼dilapidated apartment buildings废弃的地铁站abandoned underground stations钢铁巨兽的未来主义建筑futuristic buildings of steel giants独特的废弃矿井unique abandoned mines城市中心的高桥high bridges in the centre of cities破败的仓库区dilapidated warehouse areas未来主义立交桥futuristic overpasses巨型城市塔楼giant urban towers高层公寓high-rise flats混凝土丛林concrete jungles废弃的办公大楼abandoned office buildings高科技实验室high-tech laboratories宏伟的桥梁magnificent bridges巨大的地下设施huge underground facilities发电厂power plants防空洞air raid shelters高速公路桥motorway bridges废弃的工业区abandoned industrial areas未来主义的宇宙站futuristic cosmic stations高科技商业中心high-tech commercial centres科技领域的大型研发基地large R&D bases in the field of science and technology 高科技军事基地high-tech military bases科技学院science and technology colleges炼油厂oil refineries气象站weather stations军火库armouries研究所research institutes氛围与情感：无助的孤独Atmosphere and emotion: helpless loneliness 幸存者的希望hope of survivors犯罪行动的紧张tension of criminal action黑暗力量的压迫感oppression of dark forces黑暗的压迫感oppression of darkness绝望的孤独感loneliness of despair亢奋的兴奋感exhilarating excitement危险的紧张感tension of danger科技的未来感futuristic sense of technology刺激的冒险感exciting sense of adventure神秘的不可知感mysterious sense of unknowability迷幻的感觉psychedelic feeling幸存者的希望感sense of hope of survivors灰暗的丧失感grey sense of loss失落与绝望loss and despair未来世界的孤独感loneliness of a future world生存的希望与勇气hope of survival and courage科技带来的愉悦感the pleasure of technology黑客的兴奋感the excitement of hacking未来社会的不安感the uneasiness of future society高科技设备的刺激感the excitement of high-tech devices未知领域的神秘感the mystery of unknown territories科技研究的探索感the exploration of technological research 黑科技的迷茫感the confusion of black technology未来世界的理想主义the idealism of the future world科技的浪漫情怀the romance of technology科技带来的自由感the freedom that technology brings未来的疑惑与困惑the doubt and confusion of the future科技为人类带来的进步感the sense of progress that technology brings to humanity未来世界的危机感the crisis of the future world科技的创新和挑战the innovation and challenges of technology910光线与影子：闪耀的霓虹灯Light and shadow: shimmering neon lights黑暗中的影子shadows in the dark照亮城市的月光moonlight illuminating the city强烈的阳光strong sunlight熠熠生辉的霓虹灯glittering neon lights黑暗中的神秘影子mysterious shadows in the dark照亮城市的月光moonlight illuminating the city强烈的阳光strong sunlight折射光线下的变幻光影changing light in refracted light闪烁不定的烛光flickering candlelight星光下的美丽影像beautiful images in starlight柔和的阴影soft shadows梦幻般的光影效果dreamy light effects烟雾中的迷离影像misty images in smoke未来主义的夜景futuristic night scenes红色的霓虹灯光the red neon light充满幻想的星空fantasy starry skies机器人的投影projections of robots未来的科技光束beams of future technology黑暗中的眼睛eyes in the dark闪耀的星星shining stars照亮未来的激光光束laser beams illuminating the future强烈的太阳光线intense sun rays电影中的未来世界光影light and shadows in the future world in films虚拟现实中的光影light and shadows in virtual reality高科技眼镜的反射光reflected light from high-tech glasses未来世界中的阴影与光影shadows and light in the future world未来世界的幻想与现实交织fantasy and reality intertwined in the future world 机器人身上的光线投影light projections on robots未来的科技成为生活中的一部分the future of technology becoming a part of life黑暗中的未知形态unknown forms in the darkness.11能量与力量：高科技能量场Energy and power: high-tech energy fields激光束laser beams电磁脉冲electromagnetic pulses核反应堆nuclear reactors超级电池super batteries电磁脉冲的瘫痪力the paralysing power of electromagnetic pulses核反应堆的能量源the energy source of nuclear reactors超级电池的持久力the staying power of super batteries量子力学的变幻力量the shifting power of quantum mechanics黑洞的引力力量the gravitational power of black holes核聚变的能量释放力量the energy-releasing power of nuclear fusion电磁风暴的毁灭力量the destructive power of electromagnetic storms高速磁力驱动的力量the power of high-speed magnetic drives能量场的波动fluctuations in energy fields电子设备的节能模式energy-saving modes of electronic devices能量场的屏蔽效应the shielding effect of the field高科技武器的杀伤力the lethality of high-tech weapons机械臂的承重能力the weight-bearing capacity of mechanical arms科技设备的耗电量the power consumption of technological equipment 核反应堆的输出能力the output of nuclear reactors电磁脉冲的破坏力the destructive power of electromagnetic pulses飞船发动机的推力the thrust of spaceship engines高科技燃料的能量密度the energy density of high-tech fuels太阳能发电的效率the efficiency of solar power generation高科技设备的稳定性能the stability of high-tech equipment能量转换的效率the efficiency of energy conversion核聚变的热释放量the heat release of nuclear fusion高科技设备的传输效率the transmission efficiency of high-tech equipment 能量流动的稳定性the stability of energy flow12人工生命：合成人类Artificial life: synthetic humans机器人助手robotic assistants仿生生物bionic beings智能宠物intelligent pets克隆人类cloned humans合成人类的身体优势physical advantages of synthetic humans机器人助手的灵活性flexibility of robotic assistants仿生生物的自我进化self-evolution of bionic beings智能宠物的陪伴感companionship of intelligent pets克隆人类的完美基因perfect genes of cloned humans混合生物的多样性diversity of hybrid beings强化人类的肉体能力physical capabilities of enhanced humans多重人格的思维方式multiple personalities of thinking未来生命体的神秘力量mysterious powers of future lifeforms神秘生物的未知威胁unknown threat仿生机器人的情感emotions of bionic robots智能宠物的互动性interactivity of intelligent pets克隆人的道德争议moral controversies of human cloning合成人类的自我意识self-awareness of synthetic humans机器人助手的便利性convenience of robotic assistants仿生生物的生物力学特性biomechanical properties of bionic beings智能机器人的学习能力learning capabilities of intelligent robots虚拟人的真实感realism of virtual humans未来主义人类的演化evolution of futuristic humans机械生命体的意识认知consciousness perception of mechanical lifeforms人工智能的道德问题moral issues of artificial intelligence仿生人类的生理构造physiological constitution of bionic humans机器人研究的进展advances in robotics research人造生命的探索The Quest for Artificial Life人工智能的学习方法Learning Methods in Artificial Intelligence智能机器人的自我保护能力Self-Preservation Capabilities of Intelligent Robots 人类基因编辑的伦理问题Ethical Issues in Human Gene Editing合成生命体的可控性Controllability of Synthetic Lifeforms13奇异景象：穿越时空的漩涡Strange sights: vortexes through time and space奇怪的异形怪物strange alien monsters虚拟现实空间virtual reality space幻觉和幻觉药物hallucinations and hallucinogenic drugs神秘的传送门mysterious portals奇怪的异形怪物strange alien monsters虚拟现实空间的幻境illusions in virtual reality space错乱的现实世界the dislocated real world幻觉药物的迷幻体验psychedelic experiences with hallucinogenic drugs 未知力量的神秘现象mysterious phenomena of unknown forces远古遗迹的探索之旅voyages of exploration through ancient ruins黑暗维度的恐怖体验horrific experiences in dark dimensions未知星球的探险旅程expeditions to unknown planets时空隧道的扭曲warping of space-time tunnels illusions of virtual worlds虚拟世界的幻觉the emergence of technological aliens科技异形的出现the exploration of unknown planets未知星球的探索the reversal of the behaviour of bionic beings 仿生生命的逆转行为the erroneous reactions of high-tech devices 高科技设备的错误反应the outbreak of technological crises科技危机的爆发the descent of aliens外星人的降临the adventure of time travel时空旅行的冒险the fantastic path of human evolution人类进化的奇妙之路the unpredictability of technological research 科技研究的不可预知性the magnetic disturbance of cosmic space宇宙空间的磁场扰动the adventure of time travel时空穿越的冒险之旅the realisation of virtual worlds虚拟世界的实现the exploration of alien worlds异形世界的探索the virtual personality of Presence虚拟人格的存在感the stormy behaviour of high-tech devices高科技设备的暴走行为the mutant evolution of the space-time tunnel宇宙与星际：星际飞船Universe and Interstellar: Starships行星探测器Planetary Probes星系之间的太空旅行Intergalactic Space Travel14外星生命体Alien Lifeforms星际飞船的科技装备Technological Equipment for Starships行星探测器的探测工具Probing Tools for Planetary Probes星系之间的太空旅行的未知冒险Unknown Adventures of Intergalactic Space Travel外星生命体的威胁与猎捕Threats and Hunting of Alien Lifeforms人类殖民地的建设与发展Construction and Development of Human Colonies星际贸易的繁荣与危机Prosperity and Crisis of Interstellar Trade星际战争的血腥与残酷Bloodshed and Cruelty of Interstellar Wars太空探险的创新与进步Innovation and Progress of Space Exploration黑洞的奇妙力量与恐怖危险Black Holes Wonderful Powers and Terrible Dangers 未知星球的神秘环境与生命Mysterious Environments and Life on Unknown Planets 行星环境的探索Exploration of Planetary Environments太空旅行的冒险Adventures in Space Travel星系间的交通系统Intergalactic Transportation Systems未知星球的探测Exploration of Unknown Planets人类在宇宙中的生存Human Survival in the Universe太阳系的演化过程The Evolution of the Solar System未来的宇宙殖民计划Future Plans for Cosmic Colonisation太空站的生命保障系统Life Support Systems on Space Stations地外文明的探索Exploration of Extraterrestrial Civilisations恒星飞船的设计Design of Stellar Spaceships黑洞的奥秘The Mystery of Black Holes宇宙中的暗物质Dark Matter in the Universe星际探险队的挑战Interstellar The challenges of expeditions星际战争的爆发the outbreak of interstellar wars科技设备在太空中的应用the use of technological devices in space星际旅行的限制the limits of interstellar travel未来的星际战略the future of interstellar strategy。

20世纪西方科幻小说的生态危机意识研究

2019年8月第40卷第4期南昌师范学院学报(社会科学)Journal of Nanchang Normal University!Social Sciences)Aug.2019Vol.40No.420世纪西方科幻小说的生态危机意识研究徐筱虹（南昌师范学院文学院，江西南昌330032）摘要：在20世纪现代科技飞速发展背景下，西方科幻小说跨越时空，拓展了人类想象的空间，激发出人类巨大的想象力、创造力，为人们打开了发展科技、探索宇宙的大门。

同时，这一时期的科幻小说也表现出一种浓浓的忧患意识，抨击了现代科技可能导致的生态危机、生态灾难以及资源浪费等种种弊端。

科幻作家们从不同的角度提出了许多人类必须面对、必须重视的生态问题，表现了对人类命运的深切忧虑和关怀，充满着浓厚的生态意识和人道主义精神。

关键词：西方科幻小说;生态危机;生态意识中图分类号：1106.4文献标识码：A文章编号：2095-8102（2019）04-0090-06A Study On the Consciousness of Ecological Crisisin20th Century Westerr Science FictionXU Xiao-hong(Nanchang Normal University，Nanchang33032，China)Abstraci:With the rapiV development of modern science and technology in the20th centuiy，western science fiction had spanned time and space which expanded the space of human icaaination，aroused human imaaination and creativity.Besides exploring the universe，it else has helped peoplo develop science and technology.In thio period，science fiction showed a strong sense of anxiety which attacked the disadvantages caused by modern science and technolooy，such as ecclogiceS crisis，ecclogicaS disaster and the waste of natural resources.Sciencc fiction writers put foreard many ecologicaS problems that human beings must facc from different angles.Theic works showed deep wory and concern for human destiny，which was full of strong ecologicaS consciousness and humanitarian spirit.Key Words:western science fiction；ecclogiceS crisis;ecologiceS consciousness科幻题材作品是一类极富吸引力的通俗读物,以科幻模式来表现作者关于科学与自然，科学与人类社会关系的思考和批判，越来越显示出其独特的魅力和现实意义。

初三英语作文介绍一位名人的成功故事

初三英语作文介绍一位名人的成功故事全文共5篇示例，供读者参考篇1My Biggest Hero: Bill GatesHi everyone! Today I want to tell you about my biggest hero, Bill Gates. He is super rich and super smart and he started the biggest computer company in the whole world! I think his story is really cool and inspiring.Bill Gates was born in 1955 in Seattle. His mom and dad were both very successful. His dad was a lawyer and his mom served on lots of important boards and committees. From a young age, Bill was really good at math and science. He loved solving tough problems!When Bill was 13 years old, something amazing happened that changed his life forever. A amazing company called Computer Center Corporation opened a computer terminal right at Bill's school! This was before personal computers even existed. Bill was totally fascinated by this crazy new technology. He spent allllll his free time learning everything he could about coding and programming.Bill was such a computer nerd that he even started getting in trouble at school for hacking into the school's computer system to get unlimited computer time! His future business partner Paul Allen also went to that school, and they became best buds bonding over their love of computers and coding.After finishing high school, Bill went to Harvard University. But he only stayed for two years, because in 1975 he dropped out to start his own little computer software company with Paul Allen. Can you believe that? Dropping out of an amazing university like Harvard just to start a tiny business? But Bill had a huge dream.The company Bill and Paul started was called Microsoft. At first, Microsoft just made programming languages and software for the very first personal computers that were just starting to be sold. But Bill Gates had a vision that personal computers would soon become a thing in every home and office! He wanted Microsoft to make the operating system and all the most important software that all those future computers would run on.In 1980, Bill Gates made a hugely important deal with a company called IBM that made Microsoft take off like a rocket ship. IBM basically let Microsoft make the operating system for all of IBM's personal computers. This operating system wascalled MS-DOS and it soon became the most popular operating system in the whole world as IBM's computers became super popular too.After MS-DOS was a big hit, Microsoft came out with an even better operating system called Windows in 1985. Windows had cool graphics and let you have multiple programs open at once on your screen. It quickly became a massive success and made Microsoft the biggest and most powerful software company on the planet!With Microsoft being so enormously successful, Bill Gates became a multibillionaire by the time he was just 31 years old. He was the youngest self-made billionaire ever at that time! He kept making Microsoft more and more dominant with programs like Microsoft Office with Word, Excel, PowerPoint and more. Basically every computer everywhere ran on Microsoft's software.Even though Bill Gates was richer than almost anyone on Earth, he didn't stop working hard to make Microsoft better and better. He spent countless hours in the office leading his team of thousands of employees. Bill was a total perfectionist and wanted Microsoft's products to be absolutely the best.When Bill Gates turned 43 in 2008, he stepped down from the day-to-day operations at Microsoft to spend more time on his philanthropy work with the Bill & Melinda Gates Foundation that he started with his wife Melinda. The foundation is all about helping poor people across the world get access to opportunities, education, healthcare, and more. So far, Bill and Melinda have given away over 50 billion to charitable causes!Even though Bill Gates isn't actively running Microsoft anymore, he is still one of the most admired figures in the business world. He worked extremely hard, was insanely smart, and most of all had a crazy big dream that he never stopped chasing. That's why he was able to take a tiny little startup and turn it into one of the biggest, most powerful companies ever.Bill Gates showed that with hard work, passion, intelligence, and perseverance, you can overcome any obstacles and achieve your wildest visions. To me, that makes Bill Gates not just an incredible businessman, but a true inspiration for kids like me. Who knows, maybe one day I'll be the next Bill Gates and start my own world-changing tech company! For now, I'm just trying my best to learn as much as I can about computers and coding, just like Bill did when he was young. With heroes like Bill Gates to look up to, anything is possible!篇2The Super Cool Story of Steve JobsHi everyone! Today I'm going to tell you all about Steve Jobs. He was an amazing guy who started a company called Apple. Apple makes really neat computers, phones, and other amazing tech gadgets that I'm sure you all use and love!Steve was born in 1955 in California. Even as a little kid, he was really curious and loved to take things apart to see how they worked. That's why he grew up to be such a genius inventor and designer.In the 1970s, Steve went to college for a little while but then dropped out. A lot of people told him he was making a big mistake, but Steve didn't care. He was determined to follow his own path.Steve had this crazy idea to build a super simple, cheap computer that anyone could use at home. No one thought it would work, but Steve didn't give up. He worked super duper hard with his friend Steve Wozniak to build the first Apple computer. They made just a few at first and sold them out of Steve's garage!Well, that little garage project turned into one of the biggest tech companies ever! Apple went on to make tons of amazing products that people went bananas over - the iMac, iPod, iPhone, iPad and more. All of Steve's creations were so beautiful, simple and user-friendly. That's why he became known as a true visionary.Being a creative genius wasn't easy though. A lot of people doubted Steve and told him his ideas would never work. They made fun of him for being a college dropout. But Steve never let the haters get him down. He always stayed positive and believed in himself no matter what.Even when bad things happened, Steve never quit. In 1985, Steve actually got fired from Apple, the company he started! Instead of being sad though, Steve started a new computer company called NeXT. It didn't do that well, but Steve kept on trying his best.Finally in 1997, Apple realized they had made a terrible mistake by firing Steve. They begged him to come back and be in charge again. Steve said yes, and soon Apple was making awesome products people loved again, like the iMac and all the i-things.Steve's big dream was to make really high quality tech that looked super cool and was easy for anyone to use. A lot of people think he totally achieved that dream with products like the iPhone, iPad and MacBooks. With Steve in charge again, Apple grew into one of the most valuable companies ever!Sadly, Steve got very sick in his later years and passed away in 2011 at the age of 56. But he left behind an incredible legacy of game-changing inventions and designs. Steve showed the whole world that if you work super hard, believe in yourself, and never give up on your vision - you can accomplish anything!I hope Steve's amazing success story inspires you guys to dream big, work hard, and never let anyone discourage you from pursuing your passions. If a poor kid who dropped out of college could build one of the biggest tech empires ever, just imagine what you can all achieve! Stay hungry, stay humble, think different - and you'll go far, just like super Steve!篇3My Favorite Super Cool Person: Marie CurieHi everyone! Today I want to tell you about someone who is totally awesome - Marie Curie! She was a famous scientist whodid really important work. Get ready to have your mind blown by how cool she was!Marie was born in 1867 in Warsaw, which is now the capital of Poland. Her full nam e was Maria Salomea Skłodowska, but I'll just call her Marie because that's easier. Her family didn't have much money, but they really valued education. Even though schools in Poland didn't allow girls to get as much learning as boys back then, Marie's parents still made sure she and her sisters studied hard at home.Marie was such a brainiac! She was obsessed with science and math from a very young age. When she was just 10 years old, she performed her first little chemistry experiment all by herself. Cool, right? As a teenager, she had to take secret underground classes that were illegal because the Russian empire didn't want Polish people getting educated. But Marie didn't care - she was determined to learn as much as she could no matter what!In 1891, when Marie was 24 years old, she went to France to attend university. This was a huge deal because back then, not many women went to college, especially in science. But Marie was like, "Whatever, I'm going for it!" She studied so hard at the University of Paris and got super good grades. In 1895 she married another scientist named Pierre Curie. Not only were theypartners in marriage, but they became scientific partners too, working together on experiments.Here's where things get really cool. You know what radioactivity is, right? It's when certain elements and minerals release energy and particles. Well, Marie and Pierre Curie made some amazing discoveries about radioactivity that changed science forever! They realized that the glow from uranium wasn't caused by regular phosphorescence, but by something totally new - radioactivity from the uranium atoms themselves breaking apart.The Curies were obsessed with investigating radioactivity further. They went through tons of nasty pitchblende, which is a gross uranium rock, trying to isolate the radioactive elements inside it. After years of hard work in their lab, in 1898 they discovered two new chemical elements - radium and polonium! This was an epic breakthrough. No one had ever discovered a new element in a lab before. The Curies had to smash tons and tons of pitchblende to find just a tiny bit of radium, but they did it through sheer determination.Thanks to the Curies' work, we gained a deeper understanding of radiation and atomic structure. We learned that atoms aren't just motionless lumps, but have all this activitygoing on inside them constantly. Crazy, right? It totally changed how we understand matter at the smallest level.Unfortunately, this amazing discovery came at a huge personal cost for Marie. In 1906, her husband Pierre was killed in a tragic road accident. This was devastating for Marie, but she didn't give up on her science work. In fact, she worked even harder and became the first woman to teach at the University of Paris.In 1911, Marie's immense contributions to physics were recognized with a Nobel Prize - and get this, she was the first woman in history to win a Nobel! She received the award "in recognition of her services to the advancement of chemistry by the discovery of the elements radium and polonium." Years later in 1935, she was awarded a second Nobel Prize for her pioneering work in radioactivity, but tragically she passed away from health issues likely caused by her radiation exposure before she could receive it.It's impossible to overstate how important and influential Marie Curie's discoveries were. Her work literally kicked off the atomic age and led to our modern model of the atom's structure. It paved the way for tons of applications of radioactivity in fields like medicine for treating cancer. And perhaps most importantly,Marie shattered barriers and paved the way for women to make advances in the sciences.Even though Marie had to face so many obstacles as a woman in science, she never gave up or let anyone stop her. She was brilliant, dedicated, and tough as nails. To me, Marie Curie is the definition of a real-life superhero using her amazing intellect and determination to change the world. What an inspiring badass! I hope that one day I can be as hard working, unstoppable, and down for science as Marie Curie was. Everyone should know her awesome story!篇4My Favorite Famous Person: J.K. RowlingDo you like Harry Potter? I LOVE Harry Potter! The books about the boy wizard who goes to Hogwarts School of Witchcraft and Wizardry are my total favorites. I've read all the Harry Potter books like a million times. I even tried to use a stick as a pretend wand and say some made-up spell words, but no magic happened. Bummer!The person who wrote the amazing Harry Potter books is named J.K. Rowling. She is a writer from England and she is socool and inspiring. I really look up to her because of her incredible imagination and her amazing success story.J.K. Rowling had a very difficult life before she became a famous bestselling author. When she was a little kid, her family didn't have much money. Her parents got divorced when she was young, which must have been really hard. As a teenager, she had to deal with her mom getting very sick.After she grew up and went to university, she had an even tougher time. She moved to Portugal to teach English, but her marriage failed. She was a single mom with almost no money, living off welfare benefits. That means the government had to help pay for her rent and food. It was an incredibly difficult situation.But J.K. Rowling never gave up on her dream of becoming a writer. She started writing the first Harry Potter book in cafes whenever she could, bringing her baby daughter along. She wrote and rewrote the book over and over until she felt it was perfect.It took her a very long time to finally get the first Harry Potter book published. So many publishers rejected her book at first! They didn't think it would be popular enough. But J.K.Rowling never stopped believing in her story about the young wizard.Finally, a publisher decided to take a chance on Harry Potter and the Sorcerer's Stone in 1997. And boy, are they glad they did! The Harry Potter series turned into a massive, world-wide phenomenon. Kids and adults of all ages fell in love with the magical books.All seven of the Harry Potter novels ended up becoming gigantic bestsellers. They sold over 500 million copies around the world! The books were turned into eight blockbuster movies too, which made billions of dollars. J.K. Rowling went from being poverty-stricken to becoming a multi-millionaire.Her story shows that you should never give up on your dreams, no matter how impossible they might seem. J.K. Rowling worked extremely hard and overcame so many obstacles and setbacks in her life. It just goes to show that with talent, determination, and an unwavering belief in yourself, you can achieve anything you set your mind to.I really admire how J.K. Rowling used her difficult life experiences as inspiration to create the heartwarming stories about Harry Potter. After her own struggles with poverty, loss of family, and trying to raise a child as a single parent, she was ableto imagine the trials and tribulations that Harry faced with such authenticity.Her books taught important lessons about love, friendship, bravery, and the magic that lies within all of us. They encouraged kids like me to read for fun and awakened our imaginations. J.K. Rowling's novels allowed us to get lost in a whole other whimsical, wondrous world of wizards and witches.In the end, that's why I so admire J.K. Rowling as a famous person. She never stopped pursuing her passion for writing and storytelling, despite all the roadblocks and hardships she faced. Her determination, perseverance, and unwavering self-belief allowed her to achieve unimaginable levels of success and acclaim.Thanks to her brilliance and grit, J.K. Rowling took an ordinary world and added her own extraordinary magic to it through the Harry Potter series. Her books sparked an unparalleled sense of joy, imagination, and inspiration for millions upon millions of readers like myself across the globe. For that, J.K. Rowling will forever remain my favorite famous person and role model!篇5My Hero: J.K. Rowling's Amazing Life StoryHi everyone! Today I want to tell you all about my biggest hero, J.K. Rowling. She's the super cool author who wrote the Harry Potter books! I think her life story is the most inspirational ever.J.K. Rowling was born in England in 1965. Her full name is Joanne Rowling, but she used the initials J.K. because her publishers were worried that boys wouldn't want to read books written by a woman back then. How silly is that?When she was little, Joanne loved to read and make up fantasy stories. Even as a kid she was a gifted writer. But her family didn't have a lot of money, and her teenage years were pretty rough. Her mom got really sick, and she struggled with poverty.After finishing school, Joanne had some ups and downs trying to become a writer. She worked as a secretary and taught English in Portugal for a while. In 1990, while riding on a train, she came up with the idea for a book about a young wizard named Harry Potter. Genius!For several years, Joanne outlined the epic Harry Potter series while raising her baby daughter Jessica as a single mom.Money was super tight, and she was living on welfare benefits at one point. But she never gave up on her dream.Finally in 1997, her first book "Harry Potter and the Sorcerer's Stone" was published. It became an instant mega hit! Readers of all ages fell in love with the magical world she created at Hogwarts School of Witchcraft and Wizardry.Over the next ten years, J.K. Rowling wrote and published six more books about Harry and his brave adventures battling the evil Lord Voldemort. The books smashed all records, selling over 500 million copies worldwide in 80 languages! They were turned into eight blockbuster movies too.From being broke and on welfare, J.K. Rowling is now one of the richest and most famous writers ever. She's worth over a billion dollars! But she hasn't let her mind-blowing success go to her head.J.K. Rowling is humble and extremely generous. She has donated millions to charity, fighting poverty and helping kids get an education. She's an inspiring role model for dreamers everywhere.Her Harry Potter books taught us that love, friendship and courage can overcome anything. They inspired an entiregeneration to get passionate about reading. J.K. Rowling showed that magical things can happen when you combine imagination, determination and hard work.I love how she never gave up on her ambitions, no matter how tough things got. From a talented kid growing up poor, to a struggling single mom, to one of the most iconic writers of all time, her journey fills me with hope and excitement.While money is great, J.K. Rowling's most prized achievement is the positive impact she's had on millions of kids' lives through literature. She made reading fun and creative again! Thanks to her captivating wizarding world, so many of us became avid bookworms at a young age.Smart, kind and wildly imaginative, J.K. Rowling used her wits and grit to weave an unforgettable magical spell with words. Her rebellious spirit and perseverance in the face of adversity taught us to hold on to our dreams, no matter what.The Boy Who Lived will live on forever, but J.K. Rowling's status as a real-life hero and role model for breaking barriers is truly immortal. From the bottom of my heart, I thank her for the priceless gifts of Harry Potter and proving that anything is possible if you believe. She's simply the best, brilliant, brightest witch of her age!。

分子生物学名词解释最全（3）

分子生物学名词解释最全（3）分子生物学名词解释最全att sites(att位点)：在噬菌体和细菌染色体噬菌体插入或切除细菌染色体的位点。

attenuation (衰减)：控制一些细菌启动子表达中涉及的转录终止调控。

attenuator (衰减子)：衰减发生处的一种内部终止子序列。

autogenous control (自体调控)：基因产物减弱(负自体调控)或者激活(正自体调控)其编码基因表达的作用。

autonomous controlling element(自主控制元件)：玉米中一种具有转座能力的转座元件。

autoradiography(放射性子显影)：通过放射性标记分子在胶卷上留下图像检测分子的方法。

autosomes (常染色体)：除性染色体外的所有染色体。

二倍体细胞拥有两套常染色体。

bb lymphocytes or b cell (b淋巴细胞或b细胞)：合成抗体的细胞。

backcross (回交)：杂交检测的另一种(早期的)说法。

back mutation(回复突变)：逆转产生基因失活效果突变的突变，从而使细胞恢复野生型。

bacteriophage (细菌噬菌体)：侵染细菌的病毒，通常简称为噬菌体。

balbiani ring (b环)：多线染色体条带中一个很大的泡状环。

normal chromosomes(常染色体)：相对较大，一定区域内在特定化学处理下保持着色。

base pair (碱基对)：是dna双链中一对a和t或g和c。

在rna 中特定条件下也能形成其它的配对。

bidirectinal replication(双向复制)：当两个复制叉在同一起始点以不同的方向移动时形成。

bivalent(二价染色体)：在减数分-裂初期一种包括四条染色单体的结构(两个染色单体代表同源染色体)。

blastoderm(囊胚层)：昆虫胚胎发育的一个阶段，其中胚胎周围的一层细胞核或细胞围绕着中央的卵黄。

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Dept. of EE, University of Nsity evolution
• Empirically, LDPC performance is excellent – LDPC codes have been shown to be the best known block codes. However, what can be said analytically? • At ﬁrst, this problem seems impossible! Even what is calculated by the SPA is unknown when the factor graph has cycles. • Three key insights make the problem simpler
(2 ) (2 )
is cycle-free with Pr → 1 as n → ∞.
• Thus, messages passed through the graph are conditionally independent
Dept. of EE, University of Notre Dame
Dept. of EE, University of Notre Dame
Density Evolution
Outline
1. Brief review of LDPC codes – Factor graph representations – Sum-product decoding 2. Density evolution 3. Approximate density evolution 4. Recent applications and meta-analysis
Dept. of EE, University of Notre Dame
Density Evolution
Motivation
• Heavy research into turbo-like codes: Low-Density Parity-Check (LDPC) codes rediscovered, with excellent empirical performance • What can be said analytically about the performance of these codes?
Density Evolution
Density evolution
• Key Insight 2: – Channel outputs can be represented y = x · z, z ⊥ x – For each calculation, if uin = x · z, the output can be written uout = x · z • Symmetry Condition: – Any message u has a PDF fU (u) – Obviously, for any message u, if u = x · z , then fU (u|x = 1) = fU (−u|x = −1) – Because the LDPC code is linear, it contains the all-one codeword – Thus, it is suﬃcient to calculate DE assuming that the all-one codeword was sent
x1
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h1
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h3
Dept. of EE, University of Notre Dame
Density Evolution
Outline
1. Brief review of LDPC codes 2. Density evolution – Key insights – The algorithm – Limitations 3. Approximate density evolution 4. Recent applications and meta-analysis
M C Li M =C+
i Li
– At check:
M M = 2atanh( Li
i tanh(Li /2))
Dept. of EE, University of Notre Dame
Density Evolution
Representing and decoding LDPC codes
• Message passing schedule. First calculate messages at all variables, and pass to the checks; then calculate messages at all checks, and pass to the variables.
Dept. of EE, University of Notre Dame
Density Evolution
Density evolution
• The main idea: Messages passed in the factor graph are random variables. The calculations performed under the SPA are functions of random variables. Let fU (u) be the PDF of the messages passed at the ith iteration. Then fU
Dept. of EE, University of Notre Dame
Density Evolution
Representing and decoding LDPC codes
• Factor graph representation of an LDPC indicator function H(x) – Draw circles representing each codeword symbol in x – Draw boxes representing each term in H(x) (i.e., each parity check) – Draw an edge connecting the ith circle with the jth box if hj is a function of xi H(x) = h1(x1, x3, x4, x5)h2(x1, x2, x4, x6)h3(x1, x2, x3, x7)
Dept. of EE, University of Notre Dame
Density Evolution
Outline
1. Brief review of LDPC codes 2. Density evolution 3. Approximate density evolution 4. Recent applications and meta-analysis
Density Evolution: A Powerful Analytical Tool for LDPC Codes
Andrew W. Eckford Department of Electrical Engineering University of Notre Dame
IMA Summer Program in Mathematics June 18, 2004
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x3
x4
x5
x6
x7
h1
h2
h3
Dept. of EE, University of Notre Dame
Density Evolution
Representing and decoding LDPC codes
• Message passing schedule. First calculate messages at all variables, and pass to the checks; then calculate messages at all checks, and pass to the variables.
x1 x2 x3 x4 x5 x6 x7
h1
h2
h3
Dept. of EE, University of Notre Dame
Density Evolution
Representing and decoding LDPC codes
• Sum-product decoding of an LDPC code – Message-passing algorithm; all messages are log-likelihood ratios – At variable:
(i+1) (i)
(u) can be found from fU (u) under certain circumstances.
(i)
(i)
0 • Probability of error: −∞ fU (u|x = 1)du
• A related idea was given by Gallager (1962)
Dept. of EE, University of Notre Dame
Density Evolution
Density evolution
• Path of length d: A sequence of adjacent nodes through a factor graph that traverses exactly d edges • Directed local neighborhood to depth d of edge e, Ne : The set of all paths of length d starting at v, such that e is not the ﬁrst edge in the path