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钙钛矿太阳能电池课件PPT

钙钛矿太阳能电池课件PPT
Efficient planar heterojunction perovskite solar cells by vapour deposition
Nature 501, 395 (202X) 英国牛津大学Henry Snaith小 组,15.4%
Sequential deposition as a route to high-performance perovskite-sensitized solar cells
染料敏化电池的研发方向和内容
光阳极膜性能的提高。制备电子传导率高、抑制电荷 复合的高性能多孔半导体膜,并优化膜的性能;改进 制膜的方法,使其工艺更简单、成本更低;寻找其它 可代替TiO2 的氧化物半导体。
染料敏化效果的提高。设计、合成高性能的染料分子, 并改善分子结构,提高电荷分离效率,使染料具有更 优异的吸收性能和光谱吸收范围;充分利用多种染料 的特征吸收光谱的不同,研究染料的协同敏化,拓宽 染料对太阳光的吸收光谱。
光敏层,即钙钛矿光吸收层,接受光照激发产生光电 子,注入到多孔半导体层。后来的研究发现,该光敏 层同时具有电子传输功能。
空穴传输材料,捕获空穴,代替传统染料敏化电池中 的电解液,对于制造全固态敏化电池是一个大的突破。
金属电极,即背电极,在染料敏化电池结构中相当于 对电极。
Michael Gratzel小组的最新成果
钙钛矿太阳能电池
《科学》杂志评选202X年度十大科学突 破,第3项。钙钛矿型太阳能电池: 一种 新时代的太阳能电池材料在过去的这一 年中获得了大量的关注,它们比那些传 统的硅电池要更便宜且更容易生产。钙 钛矿电池还没有像商用太阳能电池那样 有效,但它们正在快速不断地得到改善。
美国宾州大学的Andrew Rappe研究组,将钙 钛矿结构的铁电晶体用于光伏转换,提高光吸 收效率,号称转换效率可达50%以上。目前只 是材料和结构的设想,尚未制作出实际器件。

英文刊名缩写

英文刊名缩写

第 2 页,共 52 页
72 86 87 88 89 90 91 92 93 94 95 96 97 98 99
ASTROPHYS J SUPPL S MON NOT R ASTRON SOC ASTRON J ANNU REV EARTH PL SC ASTRON ASTROPHYS ASTRON ASTROPHYS REV NEW ASTRON METEORIT PLANET SCI PUBL ASTRON SOC PAC ICARUS REV MEX ASTRON ASTR SOL PHYS PROG MATER SCI
地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学 地学天文 地学天文
2.17 2.16 2.13 2.08 2.04 2.00 1.94 1.91 1.86 1.81 1.81 1.80 1.77 1.77 1.73 1.71 1.69 1.68 1.66 1.65 1.64 1.62 1.60 1.59 1.58 1.58 1.58 1.53 1.52 1.51 1.51 1.50 1.46 1.46 1.43 13.14 6.24
JOURNAL OF THE GEOLOGICAL SOCIETY JOURNAL OF HYDROMETEOROLOGY GEOSTANDARDS NEWSLETTER-THE JOURNAL OF GEOSTANDARDS AND GEOANALYSIS JOURNAL OF PHYSICAL OCEANOGRAPHY HOLOCENE JOURNAL OF GEOLOGY MONTHLY WEATHER REVIEW CLIMATIC CHANGE JOURNAL OF QUATERNARY SCIENCE JOURNAL OF PALEOLIMNOLOGY REVIEWS IN MINERALOGY & GEOCHEMISTRY SEDIMENTOLOGY AMERICAN MINERALOGIST MARINE GEOLOGY BOREAS ORGANIC GEOCHEMISTRY IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING JOURNAL OF STRUCTURAL GEOLOGY JOURNAL OF GLACIOLOGY INTERNATIONAL JOURNAL OF CLIMATOLOGY BASIN RESEARCH ATMOSPHERE-OCEAN INTERNATIONAL JOURNAL OF EARTH SCIENCES APPLIED CLAY SCIENCE JOURNAL OF APPLIED METEOROLOGY NORWEGIAN JOURNAL OF GEOLOGY TELLUS SERIES A-DYNAMIC METEOROLOGY AND OCEANOGRAPHY APPLIED GEOCHEMISTRY ATMOSPHERIC CHEMISTRY AND PHYSICS MINERALIUM DEPOSITA TECTONOPHYSICS JOURNAL OF MARINE RESEARCH BULLETIN OF VOLCANOLOGY GEOLOGICAL MAGAZINE BOUNDARY-LAYER METEOROLOGY ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS ASTROPHYSICAL JOURNAL

Solar Energy The Ultimate Renewable Resource

Solar Energy  The Ultimate  Renewable Resource

Advantages and Disadvantages
Advantages All chemical and radioactive polluting byproducts of the thermonuclear reactions remain behind on the sun, while only pure radiant energy reaches the Earth. Energy reaching the earth is incredible. By one calculation, 30 days of sunshine striking the Earth have the energy equivalent of the total of all the planet’s fossil fuels, both used and unused!
Energy Band Diagram of a Conductor, Semiconductor, and Insulator
a conductor
a semiconductor
an insulator
Semiconductor is interest because their conductivity can be readily modulated (by impurity doping or electrical potential), offering a pathway to control electronic circuits.
Solar Energy to Heat Living Spaces
Proper design of a building is for it to act as a solar collector and storage unit. This is achieved through three elements: insulation, collection, and storage.

ペロブスカイト太阳电池中の子振る舞いの解明

ペロブスカイト太阳电池中の子振る舞いの解明

ペロブスカイト太陽電池中の電子の振る舞いを解明~高効率太陽電池の実現に道~概要化学研究所の山田泰裕特定准教授(ナノ界面光機能寄附研究部門[住友電工グループ社会貢献基金])、金光義彦教授、若宮淳志准教授、遠藤克博士研究員らの研究グループは、新しい太陽電池材料として近年活発な研究が行われているハライド系有機-無機ハイブリッド型ペロブスカイト半導体(CH3NH3PbI3)中の電子の振る舞いの解明に成功しました。

無尽蔵の太陽光エネルギーを利用する太陽電池は、最も重要な再生可能エネルギー創出技術の一つとして、ますますその重要性が増しています。

太陽光エネルギーをさらに有効に利用するため、安価でかつ高効率な太陽電池の実現に向けた熾烈な研究・開発競争が世界中で活発に行われています。

現在、最も普及が進んでいるシリコン太陽電池の場合、太陽光エネルギーの電気エネルギーへの変換効率はおよそ25%に達していますが、さらなる太陽電池の普及のためには、低コスト化・高効率化が求められており、新たな太陽電池材料の開発研究が進められています。

ハライド系有機-無機ペロブスカイト半導体(CH3NH3PbX3)は、2009年に初めて太陽電池材料として報告された材料でありますが、基板やフィルムに「塗る」ことで作製できるという特徴をもちます。

これを光吸収材料に用いたペロブスカイト太陽電池は「印刷技術」により作製でき、従来の太陽電池に比べて製造コストを大幅に下げることが可能な新たな太陽電池として世界中で急速に注目を集めております。

2012年以降、その光電変換効率は驚異的な速さで改善が進み、一躍、次世代太陽電池研究の主役の座に躍り出ました。

その効率は20%にも届こうとしており、実用化への期待も大いに高まっています。

しかしながら、急速に進む応用研究の一方で、高い変換効率をもたらす鍵となる基礎的な物性の理解はほとんど得られていませんでした。

特に、本太陽電池の最も本質的な物性の一つであり、さらなる効率向上のために必要不可欠であります「光によって半導体中に形成される電子の振る舞い」については、これまで未解明のままでありました。

湖南省长沙市长郡中学2024-2025学年高三上学期月考试卷(一)英语试卷

湖南省长沙市长郡中学2024-2025学年高三上学期月考试卷(一)英语试卷

湖南省长沙市长郡中学2024-2025学年高三上学期月考试卷(一)英语试卷一、阅读理解As Pakistan and China are marking 2023 as a Year of Tourism, Pakistan’s breathtaking natural beauty, diverse cultural heritage and historical landmarks are all set to catch the attentionof tourists.Balochistan: Nature’s Bounty UnveiledStretching across vast expanses, Balochistan is Pakistan’s largest province, boasting not only abundant mineral resources but unique natural beauty. Its mountain ranges, mines and extensive coastal belt, which is home to the prosperous Gwadar Port, attract adventurers.Punjab: A Tapestry of History and HeritageIn the heart of Pakistan lies Punjab province, a land of green agricultural fields, intricate (交错的) river networks, ancient forts and charming Mughal-era gardens. Over two millennia (千年) ago, the Gandhara Buddhist civilization thrived in northern Pakistan, with Taxil a serving as its primary center of learning.Sindh: A Tapestry of History and CultureSindh, in Pakistan’s southern region, weaves together a tale of history and natural beauty. Itis home to the ancient city of Mohenjo-Daro, a relic of the Indus Valley Civilization, along with the modern city of Karachi and its picturesque coastline.Northern Pakistan: Nature’s MasterpieceSpread over 72,496 square kilometers, Pakistan’s northern regions are a masterpiece of nature. Among towering peaks, including numerous summits over 8,000 meters, peaceful valleys like Gilgit, Hunza and Skardu offer a brief escape.As Pakistan invites the world to explore its diverse and fascinating landscapes, it also extends a warm invitation to discovery the history, spirituality and natural wonders that define this remarkable nation.1.As a Buddhist, your favorite destination in Pakistan might be __________.A.Balochistan B.Punjab C.Sindh D.Gilgit2.What do the four parts have in common?A.Natural beauty.B.Historical origin.C.Cultural relics.D.Diverse resources.3.The passage serves as a(n) __________.A.guidance B.introduction C.commercial D.noticeThere comes a time when the old must give way to the new, and it is not possible to preserve everything from our past as we move towards the future. Finding and keeping the right balance between progress and the protection of cultural sites can be a big challenge.Big challenges, however, can sometimes lead to great solutions. In the 1950s, the Egyptian government wanted to build a new dam across the Nile in order to control floods, produce electricity, and supply water to more farmers in the area. But the proposal led to protests. Water from the dam would likely damage a number of temples and destroy cultural relics that were an important part of Egypt’s cultural heritage. After listening to different voices, the government turned to the United Nations for help in 1959.A committee was established to limit damage to the Egyptian buildings and prevent the loss of cultural relics. The group asked for contributions from different departments and raised funds within the international community. Experts investigated the issue, conducted several tests, and then made a proposal for how the buildings could be saved. Finally, a document was signed, and the work began in 1960.The project brought together governments and environmentalists from around the world. Temples and other cultural sites were taken down piece by piece, and then moved and put back together again in a place where they were safe from the water. In 1961, German engineers moved the first temple. Over the next 20 years, thousands of engineers and workers rescue d 22 temples and countless cultural relics. Fifty countries donated nearly $80 million to the project. When the project ended in 1980, it was considered a great success. Not only had the countries found a path to the future that did not run over the relics of the past, but they had also learnt that it was possible for countries to work together to build a better tomorrow.The spirit of the Aswan Dam project is still alive today. If a problem seems too difficult for a single nation, the global community can sometimes provide a solution.4.What was the major concern regarding the construction of the new dam?A.The damage to local farms.B.The high cost of the construction.C.The disapproval of local communities.D.The potential harm to cultural remains.5.How were the cultural sites rescued?A.By rebuilding similar cultural sites.B.By building fences around them.C.By taking them down into pieces.D.By removing and piecing them together again.6.Which of the following best describes the Aswan Dam project?A.International cooperation is not necessary for large-scale projects.B.It is possible to achieve progress without sacrificing cultural heritage.C.The opinions of experts should be ignored in favor of popular opinion.D.Countries should always prioritize their own interests over global concerns.7.What is the key to the success of the Aswan Dam project?A.Trial and error.B.Adequate investment.C.Global cooperation.D.Careful investigation.Since the last ice age, humans have cleared nearly half of the earth’s forests and grasslands for agriculture. With the world population expanding, there’s ever-increasing pressure on farmland to produce not only more food but also clean energy. In places such as Yakima County, Washington, it’s created competition for space as land-hungry solar panels (板) consume available fields. Last month, the state approved plans to cover 1,700 acres of agricultural land with solar panels, fueling concerns over the long-term impacts of losing cropland.A recent study from the University of California, however, shows how farmers may soon harvest crops and energy together. One researcher, Majdi Abou Najm, explains that visible light spectrum (光谱) can be separated into blue and red light waves, and their photons (光子) have different properties. Blue ones have higher energy than red ones. While that gives blue light what is needed to generate power, it also results in higher temperatures. “From a plant angle, redphotons are the efficient ones,” says Abou Najm. “They don’t make the plant feel hot.”A goal of the study is to create a new generation of solar panels. He sees potential in the organic solar cells, which come from carbon-based materials. Thin and transparent, the cells are applied like a film onto various surfaces. This new technology could be used to develop special solar panels that block blue light to generate power, while passing the red light on to crops planted directly below. These panels could also provide shade for heat-sensitive fruits during the hottest part of the day.By 2050, we’ll have two billion more people, and we’ll need more food and more energy. By maximizing the solar spectrum, “we’re making full use of an endlessly sustainable resource,” says Abou Najm. “If a technology kicks in that can develop these panels, then the sky is the limit on how efficient we can be.”8.What problem does the first paragraph focus on?A.Losing cropland to solar panels.B.Distribution of the world population.C.Reduction in forests and grasslands.D.Competing for land between farmers.9.What does the underlined word “that” in paragraph 2 refer to?A.Generation of solar power.B.Hot weather increasing efficiency.C.Blue photons having higher energy.D.Separation of visible light spectrum.10.What do we know about the organic solar cells?A.They make fruits heat-sensitive.B.They can cool down in hot days,C.They allow red light to pass through.D.They can store carbon-based materials.11.What does Abou Najm think of the future of the new solar panels?A.Limited.B.Promising.C.Uncertain.D.Challenging.While Industry 5.0 is believed to have started in 2020, the rise of AI in recent years has led experts to say it is now coming. Imagine AI-powered robots that see, hear, touch and more, pooling fresh data from across those groups of sensors to create that data with the vast ranges of digital data stored elsewhere online. The age is a major leap from the First Industrial Revolution, when steam engine started to achieve widespread commercial use.Professor John Nosta says, “The integration of sensory capabilities into AI models is not merely a technological leap. It represents a shift in our philosophical understanding of artificial and human intelligence.”He has also referred to the new era as “the Cognitive (认知) Age,” which will completely change how humans live, work, and think about themselves. According to Nosta, humans don’t typically think of computers as “experiencing” the world themselves. But that assumption will be challenged as more advanced AI systems are hooked up to ever more and ever greater sensors. The machines won’t just be logic boxes that humans input data and commands for processing. The AI will collect that data more and more on its own, experiencing the world for itself.“This is not just about understanding words, but also about grasping the tone, pitch (音高), and emphasis, which add layers of meaning often absent in written text. Image recognition adds another layer of complexity,” he added. “For example, it can analyze photographs, identify objects, and even understand the emotional content of facial expressions.”The Johannesburg-based business school is just one of many college-level programs attempting to investigate and teach its students about the still-emerging IR 5.0. Seton Hall in New Jersey offers a three-credit course on this latest age in human technology and trade; MIT has brought in guest speakers to lecture on the concept, and many other research institutions are following suit.12.Where does IR 5.0 differ from previous industrial revolution?A.It processes data and commands.B.It interacts with humans through texts.C.It enhances human sensory capabilities.D.It employs more senses in its application. 13.Why is IR 5. 0 called the Cognitive age?A.AI collects and interprets data itself.B.AI turns written texts into voice.C.AI understands written language well.D.AI has an ability of expressing emotions 14.How do some colleges address IR 5.0?A.By offering related courses.B.By expecting more industrial revolution.C.By applying AI to the technological trade.D.By preparing for the rapid economic changes.15.What is the best title for the text?A.Al Is Approaching Us Gradually B.A New IR Is About Machine LearningC.AI Has Developed Its Own Senses D.We Are Entering IR 5.0 NowPursue Y our Dreams Today, Not TomorrowHave you caught yourself daydreaming about your dreams? We often postpone our dreams, trapped in a cycle of delay. But why wait? 16 You don’t have to take a huge, life-changing step. You can take minute steps toward a brighter future. And start right now.17 If you never try, you’re going to be weighed down by your regrets. You’re always going to wonder how your life would’ve turned out if you actually took a chance on yourself. Don’t let your future self be disappointed by your present self.It doesn’t matter how old you are or how many people have warned you that you’re never going to succeed. Even the most successful people have had their hesitations about whether they had what it took to make it in their field. 18 Embrace a mindset of determination, knowing that success is within your reach.At the end of the day, you need to carve out a path for yourself that will lead to the most satisfaction. If you allow your fear to get the best of you, you’re never going to forgive yourself.19 . It’s what you would encourage your friends to do, so why aren’t you giving yourself that same push?Sometimes, following your passion means spending a lot of your time each day. It may require making slight adjustments to your schedule, but you don’t have to sacrifice everything to follow your hearts. Try to strike a balance between your current life and your dreams. 20 Pursue your dreams now, even though that means you might need to break out of your comfort zone, and even though it means entering the unknown.A.Ask yourself what would be worse.B.Starting small is completely acceptable.C.You owe it to yourself to go after your dreams.D.New opportunities may lead to personal growth.E.If things go well, you can gradually make further shifts.F.You need to move past your insecurities and explore your full potential.G.Hard as it is, it’s crucial to wave off the doubts in the back of your mind.二、完形填空As a first-generation Asian immigrant(移民)who had grown up in poverty, I knew I was beyond 21 to be admitted into Harvard. I loved books, but it never crossed my mind to become a(n) 22 of any sort. I didn’t 23 to have unrealistic dreams.Still, something 24 me. My deskmate had 25 our friendship recently. There wasn’t a dramatic fight or disagreement. He had 26 moved on to new friends. I felt an ache in my chest that 27 night. I started doodling(涂鸦)on my notepad and then, suddenly, my hand started writing words. I’d written a poem about him. There and the page was the truth about how much it hurt to 28 him.That tiny poem was a 29 that rooted in my heart. I realized I could possibly become a writer and from that moment on. It was all I 30 to do. So I changed my field of study to English. I 31 my first short story while I was still a student. I went on to write my first novel, Girl in Translation, which became an international 32 and is taught in schools around the world.That night, I learned that art isn’t a 33 . It’s at the core of what makes us human. Although I’d believed that immigrants couldn’t 34 to be creative. I understood then that we had always been the ultimate artists. 35 ourselves again and again as we try to adapt to a new landscape.21.A.innocent B.fortunate C.dependent D.voluntary 22.A.surgeon B.lawyer C.artist D.engineer 23.A.regret B.expect C.agree D.refuse 24.A.bothered B.inspired C.interested D.satisfied 25.A.adapted to B.shown off C.broken off D.referred to 26.A.unwillingly B.cautiously C.helplessly D.simply27.A.lonely B.peaceful C.happy D.fancy 28.A.marry B.lose C.upset D.desert 29.A.romance B.seed C.secret D.shadow 30.A.hesitated B.resolved C.declined D.denied 31.A.bought B.borrowed C.priced D.published 32.A.bestseller B.effort C.challenge D.gap 33.A.necessity B.reality C.game D.luxury 34.A.pretend B.offer C.fail D.afford 35.A.rescuing B.recovering C.recreating D.relaxing三、语法填空阅读下面短文, 在空白处填入1个适当的单词或括号内单词的正确形式。

QUIZ 15

QUIZ 15

北外附校2010—2011学年度第 1学期BFLS 2011---2012 the second semesterWeekly Quiz 15 of EnglishClass6Grade6 Name周博雯 Score一 Translate. (10 points)1水星Mercury 2行星planet 3冥王星Pluto 4宇宙universe5金星Venus 6暴风windstorm 7幻想fantasy 8 温度temperature9例子example 10正在消失的disappearing 11然而but 12超音速的hypersonic13引力attraction14物理physics 15化学chemistry二Choose the right answer (20)C1. If I ____ where he lived,I ____ a note to him.A. knew,wouldB. had known,would have sentC. know,would sendD. knew,would have sentC 2. I didn't see your sister at the meeting. If she _________,she would have met my brother.A. has comeB. did comeC. cameD. had comeB 3. If you had enough money,what ________?A. will you buyB. would you buyC. would you have boughtD. will you have boughtB4.If I ____ time, I ______go for a walk.A had wouldB has willC were wouldD was wouldA5.If I ______invited, I ______go to the dinner.A were wouldB was willC were willD have didA6. If I _______ a million dollars, I ______ put it in the bank.A had wouldB has willC have willB7 If I _____ enough money, I _______ travel around the world.A has willB had wouldC DA8. If I _____ you, I _______give AIDS patient a hug.A were wouldB was willC am wouldB9 If they________ here, they _______help you.A was wouldB were wouldC am willB10 They ______ help you if______ were here.A would wereB will areC should were三用所给动词的适当形式填空(20)1. If I found(find) a purse, I would gave(give) it to the police.2. If I was(be) a bird, I would fly(fly) in the blue sky.3. If you had(have) something important, you would go( can go) now.4. If I was(be) you, I would choose(choose) this one四 .用虚拟语气完成下列句子。

Numerical Modeling of Hydraulic Fractures Interaction in Complex Naturally Fractured Formations

Numerical Modeling of Hydraulic Fractures Interaction in Complex Naturally Fractured Formations

ORIGINAL PAPERNumerical Modeling of Hydraulic Fractures Interaction in Complex Naturally Fractured FormationsOlga Kresse •Xiaowei Weng •Hongren Gu •Ruiting WuReceived:11December 2012/Accepted:14December 2012/Published online:10January 2013ÓSpringer-Verlag Wien 2013Abstract A recently developed unconventional fracture model (UFM)is able to simulate complex fracture network propagation in a formation with pre-existing natural frac-tures.A method for computing the stress shadow from fracture branches in a complex hydraulic fracture network (HFN)based on an enhanced 2D displacement disconti-nuity method with correction for finite fracture height is implemented in UFM and is presented in detail including approach validation and examples.The influence of stress shadow effect from the HFN generated at previous treat-ment stage on the HFN propagation and shape at new stage is also discussed.Keywords Hydraulic fracture network ÁNaturalfractures ÁUnconventional fracture model ÁStress shadow1IntroductionMulti-stage stimulation has become the norm for uncon-ventional reservoir development.However,one of the primary obstacles to optimizing completions in shale res-ervoirs has been the lack of hydraulic fracture models that can properly simulate complex fracture propagation often observed in these formations.Different modeling approaches recently have been developed to simulate complex fracture networks in natu-rally fractured formations (Xu et al.2009;Meyer andBazan 2011;Rogers et al.2010,2011;Dershowitz et al.2010;Nagel et al.2011;Nagel and Sanchez-Nagel 2011).Simulation of equivalent fracture network of parallel fractures developed by Xu et al.(2009)and Meyer and Bazan (2011)with simplified network geometry does not model complex interaction between fractures.Discrete fracture networks (DFNs)(Rogers et al.2010,2011;Der-showitz et al.2010)use simplified approach to model hydraulic fractures (HF)and natural fractures (NF)inter-action without considering stress shadow.More complex 3D simulators developed by Nagel et al.(2011),Nagel and Sanchez-Nagel (2011),and Fu et al.(2011)though being able to capture effects of hydraulic fracture interactions are CPU-intensive and not suitable for day-to-day engineering design and evaluations at the job site.More detailed description and comparison of existing models are given in Weng et al.(2011)and Kresse et al.(2011).A complex fracture network model,referred to as unconventional fracture model (UFM),had recently been developed (Weng et al.2011;Kresse et al.2011).The model simulates fracture propagation,rock deformation,and fluid flow in the complex fracture network created during a treatment.The model solves the fully coupled problem of fluid flow in the fracture network and elastic deformation of the fractures,based on similar assumptions and governing equations as conventional pseudo-3D (P3D)fracture models.Transport equations are solved for each component of the fluids and proppant pumped.A key dif-ference between UFM and the conventional planar fracture model is being able to simulate the interaction of hydraulic fractures with pre-existing natural fractures,i.e.,determine whether a hydraulic fracture propagates through or is arrested by a natural fracture when they intersect and subsequently propagates along the natural fracture.The branching of the hydraulic fracture at the intersection withO.Kresse (&)ÁX.Weng ÁH.Gu Schlumberger,Sugar Land,TX,USA e-mail:okresse@R.WuChevron,ETC.,Houston,TX,USARock Mech Rock Eng (2013)46:555–568DOI 10.1007/s00603-012-0359-2the natural fracture gives rise to the development of a complex fracture network.The natural fractures are cur-rently treated as closed weak planes.A crossing model that is extended from the Renshaw and Pollard(1995)interface crossing criterion,applicable to any intersection angle,has been developed(Gu and Weng2010)and validated against the experimental data(Gu et al.2011)and is integrated in the UFM.To properly simulate the propagation of multiple or complex fractures,the fracture model must take into account the interaction among adjacent hydraulic fracture branches,often referred to as‘‘stress shadow’’effect.It is well known that when a single planar hydraulic fracture is opened under afinitefluid net pressure,it exerts a stress field on the surrounding rock that is proportional to the net pressure.In the limiting case of an infinitely long vertical fracture of a constantfinite height,the analytical expres-sion of the stressfield exerted by the open fracture was provided by Warpinski and Teufel(1987),and Warpinski and Branagan(1989).It shows that the net pressure(or more precisely,the pressure that produces the given frac-ture opening)exerts a compressive stress in the direction normal to the fracture on top of the minimum in situ stress, which is equal to the net pressure at the fracture face,but quickly falls off with the distance from the fracture.At a distance beyond one fracture height,the induced stress is only a small fraction of the net pressure.Thus,the term ‘‘stress shadow’’is often used to describe this increase of stress in the region surrounding the fracture.If a second hydraulic fracture is created parallel to an existing open fracture,and if it falls within the‘‘stress shadow’’(i.e.,the distance to the existing fracture is less than the fracture height),the second fracture will in effect see a closure stress greater than the original in situ stress.As a result,it will require a higher pressure to propagate the fracture, and/or the fracture will have a narrower width,as com-pared to the corresponding single fracture.One application of stress shadow is for design and optimization of the fracture spacing between multiple fractures propagating simultaneously from a horizontal wellbore.In ultra low permeability shale formations,it is desirable to have fractures closely spaced for effective reservoir drainage.However,the stress shadow effect may prevent a fracture propagating in close vicinity of other fractures(Fisher et al.2004).The interference between parallel fractures has been studied since1980’s(Meyer and Bazan2011;Warpinski and Teufel1987;Narendran and Cleary1983;Britt and Smith2009;Cheng2009; Roussel and Sharma2010).Most of the studies are for parallel fractures under static conditions.A well known effect of stress shadow is that fractures in the middle region of multiple parallel fractures have smaller width because of the increased compressive stresses from neighboring fractures(Germanovich and Astakhov2004; Olson2008).When multiple fractures are propagating simultaneously,theflow rate distribution into the frac-tures is a dynamic process and is affected by the net pressure of the fractures.The net pressure is strongly dependent on fracture width,and hence,the stress shadow effect onflow rate distribution and fracture dimensions warrants further study.The dynamics of simultaneously propagating multiple fractures also depends on the relative positions of the initial fractures.If the fractures are parallel,e.g.,in the case of multiple fractures that are orthogonal to a horizontal wellbore,the fractures tend to repel each other,resulting in the fractures curving outward.However,if the multiple fractures are arranged in an en echelon pattern,e.g.,for fractures initiated from a horizontal wellbore that is not orthogonal to the fracture plane,the interaction between the adjacent fractures may be such that their tips attract each other and even connect(Olson1990;Yew et al.1993; Weng1993).When a hydraulic fracture intersects a secondary frac-ture oriented in a different direction,it exerts an additional closure stress on the secondary fracture proportional to the net pressure.Nolte(1991)derived this stress and takes it into account in thefissure opening pressure calculation in the analysis of pressure-dependent leakoff infissured formation.For more complex fractures,a combination of various fracture interactions as discussed above is present.To properly account for these interactions,while still being computationally efficient so it can be incorporated in the complex fracture network model,a proper modeling framework needs to be constructed.This article describes a method that is based on an enhanced2D displacement discontinuity method(DDM)by Olson(2004)for com-puting the induced stresses on any given fracture and in the rock from the rest of the complex fracture network.Frac-ture turning is also modeled based on the altered local stress direction ahead of the propagating fracture tip due to the stress shadow effect.The simulation results from the UFM model that incorporates the fracture interaction modeling are presented.2UFM Model DescriptionTo simulate the propagation of a complex fracture network that consists of many intersecting fractures,the equations governing the underlying physics of the fracturing process must be satisfied.The basic governing equations include equation governing thefluidflow in the fracture network, the equation governing the fracture deformation,and the fracture propagation/interaction criterion.556O.Kresse et al.Continuity equation assumes that fluid flow propagates along fracture network with the following mass conservationo q o s þo ðH fl "wÞo tþq L ¼0;q L ¼2h L u Lð1Þwhere q is the local flow rate inside the hydraulic fracturealong the length,"wis an average width or opening of the fracture at position s =s (x,y ),H fl(s,t )is the local height of the fracture occupied by fluid,and q L is the leak-off volume rate through the wall of the hydraulic fracture into the rock matrix per unit length (leak-off height h L times velocity u L at which fracturing fluid infiltrates into surrounding per-meable medium),which is expressed through Carter’s leak-off model.The fracture tips propagate as sharp front and the total length of the entire hydraulic fracture networks (HFNs)at any given time t is defined as L (t ).The properties of injected fluid are defined by power-law exponent n 0(fluid behavior index)and consistency index K 0.The fluid flow could be laminar,turbulent,or Darcy flow through proppant pack,and is described cor-respondingly by different laws.For the general case of 1D laminar flow of a power-law fluid in any given fracture branch,the Poiseuille law (Mack and Warpinski 2000)can be appliedo p o s ¼Àa 01"w 2n 0þ1q H fl q H fl n 0À1ð2Þwitha 0¼2K 0u n 0ðÞn0Á4n 0þ2n 0 n;u n 0ðÞ¼1H fl Z H flw ðz Þ"w2n 0þ1n 0d z ð3ÞHere,w (z )represents fracture width as a function of depth at the current position s (x,y ).Fracture width is related to fluid pressure through the elasticity equation.The elastic properties of the rock (considered as isotropic linear elastic material)are defined by Young’s modulus E and Poisson’s ratio m .For a vertical fracture in a layered medium with variable minimum and maximum horizontal stresses (r h (x,y,z )and r H (x,y,z ))and fluid pressure p ,the width profile can be determined from an analytical solution given as w ðx ;y ;z Þ¼w ðp ðx ;y Þ;h ;z Þð4ÞBecause the height of the fractures h varies,the set of governing equations also include the height growth calculation based on the approach described in Kresse et al.(2011).K Iu ¼ffiffiffiffiffiffip h 2r p cp Àr n þq f g h cp À34h !þffiffiffiffiffiffi2p h r X n À1i ¼1ðr i þ1Àr i Þh 2arccosh À2h ih Àffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffih i ðh Àh i Þp !K Il ¼ffiffiffiffiffiffip h 2r p cp Àr n þq f g h cp Àh4 !þffiffiffiffiffiffi2p h r X n À1i ¼1ðr i þ1Àr i Þh 2arccosh À2h ihþffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffih i ðh Àh i Þp !ð5Þwhere r i and h i are the minimum stress and distance fromtop of the i th layer to fracture bottom tip,p cp is the fluid pressure at a reference (perforation)depth h cp measured from the bottom tip,and K Iu and K Il are the stress intensity factors at the top and bottom tips of the fracture.The equilibrium model,which calculates fracture height based on the pressure at each position of the fracture by matching Stress Intensity Factors K Iu and K Il ,given by Eq.(5),to the fracture toughness of the corre-sponding layer containing the tips,is extended to a non-equilibrium model.The non-equilibrium height growth calculation takes into account the pressure gradient due to the fluid flow in the tip regions in the vertical direction by adding apparent toughness proportional to the fracture’s top and bottom velocities.Then fracture width w (z )at any position z measured from the bottom tip is given by Eq.(6).w ðz Þ¼4E 0p cp Àr n þq f g h cp Àh 4Àz 2!ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiz ðh Àz Þp þ4X n À1i ¼1ðr i þ1Àr i Þðh i Àz Þcosh À1z h À2h ihÀÁþh i z Àh i j j þffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiz ðh Àz Þp arccosh À2h i h2666437775ð6ÞNote that one of the limitations of UFM model,the same as for the conventional P3D models,is related to the accurate height growth calculations in the cases of complicated vertical stress profile.For the height being calculated for each fracture element,UFM model assumes that reservoir elastic properties are homogeneous,and averaged over all layers containing fracture height.Since confining stress dominates elastic properties when computing fracture width,this assumption is reasonable for many cases (Adachi et al.2007).P3D models’results are in good agreement with Planar3D models for not too complex stress profiles,and present fast and accurate engineering tools for most field applications.In addition to equations described above,the global volume balance condition must be satisfiedNumerical Modeling of Hydraulic Fractures Interaction 557Z t 0QðtÞd t¼Z LðtÞhðs;tÞ"wðs;tÞd sþZH LZ tZ LðtÞ2u L d s d t d h Lð7Þi.e.,the total volume offluid pumped during time t is equal to volume offluid in fracture network and volume leaked from the fracture up to time t.The boundary conditions require theflow rate,net pressure,and fracture width to be zero at all fracture tips.The total network consists of two major parts:Fracture Network and Wellbore.These two networks communicate through injection elements to account for perforation friction.The system of Eqs.(1)–(7),together with initial and boundary conditions,plus equations governingfluidflow in the wellbore and through the perforations represent the complete set of governing equations(Kresse et al.2011). Combining these equations and discretizing the fracture network into small elements leads to a nonlinear system of equations in terms offluid pressure p in each element,simplified as f(p)=0,which is solved by using damped Newton–Raphson method.Fracture interaction is one of the most important factors, which must be taken into account to model hydraulic fracture propagation in naturally fractured reservoirs.This includes the interaction between hydraulic fractures and natural fractures,as well as interaction between hydraulic fractures.For the interaction between hydraulic and natural fractures,a semi-analytical crossing criterion is imple-mented in UFM based on the approach described in(Gu and Weng2010;Gu et al.2011).The influence of per-meability and pore pressure effect onfluid loss into the NFs is not accounted for now,and natural fractures are treated as closed weak planes.This article focuses on modeling the interaction between hydraulic fractures.Mention that poroelastic effects currently are not included in UFM model.It is observed that in unconven-tional formations(shales)changes in pore pressure due to leakoff into the matrix are in order of inches from the fracture,so poroelastic effect may be considered negligible.3Modeling Stress ShadowFor parallel fractures,the stress shadow can be represented by the superposition of stresses from neighboring fractures. The stressfield around a2D fracture with internal pressure p can be calculated from Sneddon(1946)and Sneddon and Elliott(1946)solutions.The stress normal to the fracture is r x(Fig.1)and can be calculated from r x¼p1À"Lffiffiffiffiffiffiffiffiffiffi"L1"L2p cos hÀh1þh22À"L"L1"L2ðÞ3=2sin h sin32ðh1þh2Þ2666437775ð8Þh¼arctanÀ"x"yh1¼arctanÀ"x1þ"y;h2¼arctan"x1À"yAnd"x;"y;L;L1;L2are the coordinates and distances in Fig.1normalized by the fracture half-height h/2.Since r x varies in the y-direction as well in the x-direction,an averaged stress over the fracture height is used in the stress shadow calculation.The analytical equation(8)can be used to compute the average effective stress of one fracture on an adjacent parallel fracture and include it in the effective closure stress on that fracture.For more complex fracture networks,the fractures may orient in different directions and intersect each other.A more general approach is required to compute theeffectiveFig.2Stress shadow effect558O.Kresse et al.stress on any given fracture branch from the rest of the fracture network.In UFM,the mechanical interactions between fractures are modeled based on an enhanced2D DDM(Olson2004)for computing the induced stresses (Fig.2).In a2D,plane-strain,displacement discontinuity solu-tion,Crouch and Starfield(1983)described the normal and shear stresses(r n and r s)acting on one fracture element induced by the opening and shearing displacement dis-continuities(D n and D s)from all fracture elements.To account for the3D effect due tofinite fracture height, Olson(2004)introduced a3D correction factor to the influence coefficients C ij.The modified elasticity equations of2D DDM are as follows:r in¼X Nj¼1A ij C ijnsD jsþX Nj¼1A ij C ijnnD jnr i s¼X Nj¼1A ij C ij ss D j sþX Nj¼1A ij C ij sn D j nð9Þwhere C ij are the2D,plane-strain elastic influence coefficients,and their expressions can be found in Crouch and Starfield(1983).The matrix[C]defines the interaction between elements,e.g.,C ns ij gives the normal stress at the midpoint of the element i due to shearNumerical Modeling of Hydraulic Fractures Interaction559displacement discontinuity at the element j ,and C nn ij givesthe normal stress at the midpoint of the element i due to an opening displacement discontinuity at the element j .The 3D correction factor A ij suggested by Olson (2004)is introduced to the influence coefficients to account for the 3D effects due to finite fracture height that leads to decaying of interaction between any two fracture elements when distance between them increasesA ij¼1Àd b ijd 2ij þðh =a Þ2h i b =2ð10Þwhere h is the fracture height,d ij is the distance between elements i and j ,a =1and b =3.2are empirically derived constants (Olson 2008;Laubach et al.2004).Eq.(10)clearly shows that the 3D correction factor leads to decaying of interaction between any two fracture elements when the distance increases.In UFM model,at each time step,the additional induced stresses due to the stress shadow effects are computed.We assume that at any time,fracture width equals the normal displacement discontinuities (D n )and shear stress at the fracture surface is zero,i.e.,D n j =w j ,r s i=0.Substituting these two conditions into Eq.(9),we can find the shear displacement disconti-nuities D s and normal stress induced on each fracture element r n .The effects of the stress shadow-induced stresses on the fracture network propagation pattern are twofold.First,during pressure and width iteration,the original in situ stresses at each fracture element are modified by adding theTable 1Input data for validation against CSIRO model Injection rate 0.1m 3/s Stress anisotropy 0.9MPa Young’s modulus 391010Pa Poisson’s ratio 0.35Fluid viscosity 0.001Pa-s Fluid Specific Gravity 1.0Min horizontal stress 46.7MPa Max horizontal stress 47.6MPa Fracture toughness 1MPa-m 0.5Fracture height120m560O.Kresse et al.additional normal stress due to the stress shadow effect.This directly affects the fracture pressure and width dis-tribution,which results in a change on the fracture growth.Second,by including the stress shadow induced stresses (normal and shear stresses),the local stress fields ahead the propagating tips are also altered,which may cause the local principal stress direction to deviate from the original in situ stressdirection.Fig.6Comparison of propagation paths for two initially parallel fractures in isotropic and anisotropic stressfieldsFig.7Comparison of propagation paths for two initially offset fractures in isotropic and anisotropic stressfieldsFig.8Propagation paths for two fractures under isotropic far-field stress field depending on the relative positions of injection pointsNumerical Modeling of Hydraulic Fractures Interaction 561Thus,the local stresses around each tip elementr tip xx ;r tip yy ;r tipxy calculated by enhanced DDM approach arecombined with far-field stresses r 1xx ;r 1yy ;r 1xy r tot xx ¼r 1xx þr tip xx r tot yy ¼r 1yy þr tip yy r tot xy ¼r 1xy þr tip xyð11Þto define local principal stresses and orientation (angle a )of local maximum stress around tip elements byr 1¼r tot xxþr tot yy2þffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiðr tot xy Þ2þðr tot xx Àr tot yy Þ24s r 3¼r tot xx þr totyy 2Àffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiðr tot xy Þ2þðr tot xx Àr tot yy Þ24s a ¼12arctan 2r tot xyr xx Àr yyð12ÞThis altered local principal stress direction may result infracture turning from its original propagation plane and further affects the fracture network propagation pattern.4Validation of Stress ShadowValidation of UFM model for the cases of bi-wing fractures has been presented before (Kresse et al.2011;Weng et al.2011).This article focuses on the validation of stress sha-dow modeling approach.4.1Comparison of Enhanced 2D DDM to Flac3D The 3D correction factors suggested by Olson (2004)contain two empirical constants,a and b .Olson calibrated the values of a and b by comparing stresses obtained from numerical solutions (enhanced 2D DDM)to the analytical solution for a plane-strain fracture with infinite length and finite height.In this work,the model is further validated by comparing the 2D DDM results to full three-dimensional numerical solutions,utilizing FLAC3D (Itasca Consulting Group Inc,2002),for two parallel straight fractures with finite lengths and heights.The validation problem is shown in Fig.3.Table 2Input parameters for case of five parallel fractures Young’sl modulus 4.591010Pa Poisson’s ratio 0.35Rate 0.032m 3/s Viscosity 0.001Pa-s Height30mLeakoff coefficient 3.9910-2m/s 1/2Stress anisotropy 1.4MPa Fracture spacing 20m No.of perfs per frac100Fig.9Transverse parallel fracture in horizontalwellFig.11Fracture geometry and width (in m)for the case of five fractures5101520253035404550F r a c t u r e l e n g t h (f t )Time (min)Fig.10Length of five parallel fractures (xf1–xf5,fracture 3is at the center,and fractures 1and 5are outmost ones)during injection.The curves with markers are calculated from the simplistic PKN model and the curves without markers are from UFM model562O.Kresse et al.The fracture in Flac3D is simulated as two surfaces at the same location but with unattached grid points.Constant internalfluid pressure is applied as the normal stress on the grids.Fractures are also subjected to remote stresses,r x and r y.Two fractures have the same length and height with the ratio of height/half-length=0.3.Stresses along x-axis (y=0)and y-axis(x=0)are compared.Two closely spaced fractures(s/h=0.5)have been simulated and compared(Fig.3).As shown in Figs.4,5,the stresses simulated from the enhanced2D DDM approach with3D correction factor closely match those from the full3D simulator results.This indicates that the correction factor allows capture of the3D effect from the fracture height on the stressfield.In the mean time,simple2D DDM approach shows significant differences from full3D simulator results due to in-ability to capture effect of fracture height(fracture height is assumed infinite and influence from elements is only due to distance between them).This can be seen by comparing Figs.4and5,showing the distribution of stresses r x and r y along y-axis,and r y along x-axis for the cases when distance between fractures is small(s/h=0.5) compared to the fractures height,and when this distance is relatively large(s/h=3.3).4.2Comparison to CSIRO ModelThe UFM model that incorporates the enhanced2D DDM approach is validated against full2D DDM simulator incorporating a full solution for coupled elasticity and fluidflow equations by CSIRO(Zhang et al.2007)in the limiting case of very large fracture height(because2D DDM approach does not consider the3D effect due to the fractures’height).The comparison of the influence of two closely propagating fractures on each other’s propagation paths has been provided.The propagation of two hydraulic fractures initiated parallel to each other(prop-agating along local maximum stress direction)has been simulated for two configurations,with initiation points aligned along the y-axis and offset from each other for isotropic and anisotropic farfield stresses.The fracture propagation path and pressure inside of each fracture has been compared for UFM and CSIRO code for the input data given in Table1.When two fractures are initiated parallel to each other with initiation points separated by d x=0,d y=10m (the maximum horizontal stressfield is oriented in the x-direction),they turn away from each other due to the stress shadow effect.The propagation paths for isotropic and anisotropic stressfields are shown in Fig.6.Compared with the isotropic case,the curvatures of the fractures in the case of stress anisotropy are smaller.This is due to the competition between the stress shadow effect, which tends to turn fractures away from each other,and the far-field stresses that push fractures to propagate in the direction of maximum horizontal stress(x-direction). The influence of the far-field stress becomes dominant as the distance between the fractures increases,in which case the fractures tend to propagate parallel to the maximum horizontal stress direction(Fig.8a,b).The same conclusion about far-field stresses is applica-ble for the case when two fractures are initiated parallel to each other with initiation points separated by d x=10m, d y=10m(Fig.7).The numerical study presented above shows that the enhanced2D DDM approach implemented in UFM model is able to capture the3D effects offinite fracture height on fracture interaction and propagation pattern,while being computationally efficient.It provides good estimation of the stressfield for a network of vertical hydraulic fractures and fracture propagation direction(pattern).5Examples5.1Influence of Stress Shadow on FracturePropagation PathMore results of UFM simulations showing the influence of stress shadow on the fracture propagation pathdepending Fig.12Fracture geometry andfluid pressure(Pa)for the cases when distance between injection points is equal to10,20,and40m Numerical Modeling of Hydraulic Fractures Interaction563。

光伏发电英文文献Ultra-High Efficiency Photovoltaic

光伏发电英文文献Ultra-High Efficiency Photovoltaic

Ultra-High Efficiency Photovoltaic Cells for Large Scale Solar Power GenerationYoshiaki NakanoAbstract The primary targets of our project are to dras-tically improve the photovoltaic conversion efficiency and to develop new energy storage and delivery technologies. Our approach to obtain an efficiency over40%starts from the improvement of III–V multi-junction solar cells by introducing a novel material for each cell realizing an ideal combination of bandgaps and lattice-matching.Further improvement incorporates quantum structures such as stacked quantum wells and quantum dots,which allow higher degree of freedom in the design of the bandgap and the lattice strain.Highly controlled arrangement of either quantum dots or quantum wells permits the coupling of the wavefunctions,and thus forms intermediate bands in the bandgap of a host material,which allows multiple photon absorption theoretically leading to a conversion efficiency exceeding50%.In addition to such improvements, microfabrication technology for the integrated high-effi-ciency cells and the development of novel material systems that realizes high efficiency and low cost at the same time are investigated.Keywords Multi-junctionÁQuantum wellÁConcentratorÁPhotovoltaicINTRODUCTIONLarge-scale photovoltaic(PV)power generation systems, that achieve an ultra-high efficiency of40%or higher under high concentration,are in the spotlight as a new technology to ease drastically the energy problems.Mul-tiple junction(or tandem)solar cells that use epitaxial crystals of III–V compound semiconductors take on the active role for photoelectric energy conversion in such PV power generation systems.Because these solar cells operate under a sunlight concentration of5009to10009, the cost of cells that use the epitaxial crystal does not pose much of a problem.In concentrator PV,the increased cost for a cell is compensated by less costly focusing optics. The photons shining down on earth from the sun have a wide range of energy distribution,from the visible region to the infrared region,as shown in Fig.1.Multi-junction solar cells,which are laminated with multilayers of p–n junctions configured by using materials with different band gaps,show promise in absorbing as much of these photons as possible,and converting the photon energy into elec-tricity with minimum loss to obtain high voltage.Among the various types of multi-junction solar cells,indium gallium phosphide(InGaP)/gallium arsenide(GaAs)/ger-manium(Ge)triple-junction cells that make full use of the relationship between band gaps and diverse lattice con-stants offered by compound semiconductors have the advantage of high conversion efficiency because of their high-quality single crystal with a uniform-size crystal lat-tice.So far,a conversion efficiency exceeding41%under conditions where sunlight is concentrated to an intensity of approximately5009has been reported.The tunnel junction with a function equivalent to elec-trodes is inserted between different materials.The positive holes accumulated in the p layer and the electrons in the adjacent n layer will be recombined and eliminated in the tunnel junction.Therefore,three p–n junctions consisting of InGaP,GaAs,and Ge will become connected in series. The upper limit of the electric current is set by the mini-mum value of photonflux absorbed by a single cell.On the other hand,the sum of voltages of three cells make up the voltage.As shown in Fig.1,photons that can be captured in the GaAs middle cell have a smallflux because of the band gap of each material.As a result,the electric currentoutputAMBIO2012,41(Supplement2):125–131 DOI10.1007/s13280-012-0267-4from the GaAs cell theoretically becomes smaller than that of the others and determines the electric current output of the entire tandem cell.To develop a higher efficiency tandem cell,it is necessary to use a material with a band gap narrower than that of GaAs for the middle cell.In order to obtain maximum conversion efficiency for triple-junction solar cells,it is essential to narrow down the middle cell band gap to 1.2eV and increase the short-circuit current density by 2mA/cm 2compared with that of the GaAs middle cell.When the material is replaced with a narrower band gap,the output voltage will drop.However,the effect of improving the electric current balance out-performs this drop in output voltage and boosts the effi-ciency of the entire multi-junction cell.When a crystal with such a narrow band gap is grown on a Ge base material,lattice relaxation will occur in the middle of epitaxial crystal growth because the lattice constants of narrower band-gap materials are larger than that of Ge (as shown in Fig.2).As a result,the carrier transport properties will degrade due to dislocation.Researchers from the international research center Solar Quest,the University of Tokyo,aim to move beyond such material-related restrictions,and obtain materials and structures that have effective narrow band gaps while maintaining lattice matching with Ge or GaAs.To achieve this goal,we have taken three approaches as indicated in Fig.3.These approaches are explained in detail below.DILUTE NITROGEN-ADDED BULK CRYSTAL Indium gallium nitride arsenide (InGaNAs)is a bulk material consists of InGaAs,which contains several percent of nitrogen.InGaNAs has a high potential for achieving a narrow band gap while maintaining lattice matching with Ge or GaAs.However,InGaNAs has a fatal problem,that is,a drop in carrier mobility due to inhomogeneousdistribution of nitrogen (N).To achieve homogeneous solid solution of N in crystal,we have applied atomic hydrogen irradiation in the film formation process and addition of a very small amount of antimony (Sb)(Fig.3).The atomic hydrogen irradiation technology and the nitrogen radical irradiation technology for incorporating N efficiently into the crystal can be achieved only through molecular beam epitaxy (MBE),which is used to fabricate films under high vacuum conditions.(Nitrogen radical irradiation is a technology that irradiates the surface of a growing crystal with nitrogen atoms that are resolved by passing nitrogen through a plasma device attached to the MBE system.)Therefore,high-quality InGaNAs has been obtained only by MBE until now.Furthermore,as a small amount of Sb is also incorporated in a crystal,it is nec-essary to control the composition of five elements in the crystal with a high degree of accuracy to achieve lattice matching with Ge or GaAs.We have overcome this difficulty by optimizing the crystal growth conditions with high precision and devel-oped a cell that has an InGaNAs absorption layer formed on a GaAs substrate.The short-circuit current has increased by 9.6mA/cm 2for this cell,compared with a GaAs single-junction cell,by narrowing the band gap down to 1.0eV.This technology can be implemented not only for triple-junction cells,but also for higher efficiency lattice-matched quadruple-junction cells on a Ge substrate.In order to avoid the difficulty of adjusting the compo-sition of five elements in a crystal,we are also taking an approach of using GaNAs with a lattice smaller than that of Ge or GaAs for the absorption layer and inserting InAs with a large lattice in dot form to compensate for the crystal’s tensile strain.To make a solid solution of N uniformly in GaNAs,we use the MBE method for crystal growth and the atomic hydrogen irradiation as in the case of InGaNAs.We also believe that using 3D-shaped InAs dots can effectively compensate for the tensile strainthatFig.1Solar spectrum radiated on earth and photon flux collected by the top cell (InGaP),middle cell (GaAs),and bottom cell (Ge)(equivalent to the area of the filled portions in the figure)occurs in GaNAs.We have measured the characteristics of a single-junction cell formed on a GaAs substrate by using a GaNAs absorption layer with InAs dots inserted.Figure 4shows that we were able to succeed in enhancing the external quantum efficiency in the long-wavelength region (corresponding to the GaNAs absorp-tion)to a level equal to GaAs.This was done by extending the absorption edge to a longer wavelength of 1200nm,and increasing the thickness of the GaNAs layer by increasing the number of laminated InAs quantum dot layers.This high quantum efficiency clearly indicates that GaNAs with InAs dots inserted has the satisfactory quality for middle cell material (Oshima et al.2010).STRAIN-COMPENSATED QUANTUM WELL STRUCTUREIt is extremely difficult to develop a narrow band-gap material that can maintain lattice matching with Ge orGaAs unless dilute nitrogen-based materials mentioned earlier are used.As shown in Fig.2,the conventionally used material InGaAs has a narrower band gap and a larger lattice constant than GaAs.Therefore,it is difficult to grow InGaAs with a thickness larger than the critical film thickness on GaAs without causing lattice relaxation.However,the total film thickness of InGaAs can be increased as an InGaAs/GaAsP strain-compensated multi-layer structure by laminating InGaAs with a thickness less than the critical film thickness in combination with GaAsP that is based on GaAs as well,but has a small lattice constant,and bringing the average strain close to zero (Fig.3.).This InGaAs/GaAsP strain-compensated multilayer structure will form a quantum well-type potential as shown in Fig.5.The narrow band-gap InGaAs layer absorbs the long-wavelength photons to generate electron–hole pairs.When these electron–hole pairs go over the potential bar-rier of the GaAsP layer due to thermal excitation,the electrons and holes are separated by a built-in electricfieldFig.2Relationship between band gaps and lattice constants of III–V-based and IV-based crystalsto generate photocurrent.There is a high probability of recombination of electron–hole pairs that remain in the well.To avoid this recombination,it is necessary to take out the electron–hole pairs efficiently from the well and transfer them to n-type and p-type regions without allowing them to be recaptured into the well.Designing thequantumFig.3Materials and structures of narrow band-gap middle cells being researched by thisteamFig.4Spectral quantum efficiency of GaAs single-junction cell using GaNAs bulk crystal layer (inserted with InAs dots)as the absorption layer:Since the InAs dot layer and the GaNAs bulk layer are stacked alternately,the total thickness of GaNAs layers increases as the number of stacked InAs dot layers is increased.The solid line in the graph indicates the data of a reference cell that uses GaAs for its absorption layer (Oshima et al.2010)well structure suited for this purpose is essential for improving conversion efficiency.The high-quality crystal growth by means of the metal-organic vapor phase epitaxy (MOVPE)method with excellent ability for mass production has already been applied for InGaAs and GaAsP layers in semiconductor optical device applications.Therefore,it is technologically quite possible to incorporate the InGaAs/GaAsP quantum well structure into multi-junction solar cells that are man-ufactured at present,only if highly accurate strain com-pensation can be achieved.As the most basic approach related to quantum well structure design,we are working on fabrication of super-lattice cells with the aim of achieving higher efficiency by making the GaAsP barrier layer as thin as possible,and enabling carriers to move among wells by means of the tunnel effect.Figure 6shows the spectral quantum effi-ciency of a superlattice cell.In this example,the thickness of the GaAsP barrier layer is 5nm,which is not thin enough for proper demonstration of the tunnel effect.When the quantum efficiency in the wavelength range (860–960nm)that corresponds to absorption of the quan-tum well is compared between a cell,which has a con-ventionally used barrier layer and a thickness of 10nm or more,and a superlattice cell,which has the same total layer thickness of InGaAs,the superlattice cell demonstrates double or higher quantum efficiency.This result indicates that carrier mobility across quantum wells is promoted by even the partial use of the tunnel effect.By increasing the P composition in the GaAsP layer,the thickness of well (or the In composition)can be increased,and the barrier layer thickness can be reduced while strain compensation is maintained.A cell with higher quantum efficiency can befabricated while extending the absorption edge to the long-wavelength side (Wang et al.2010,2012).GROWTH TECHNIQUE FOR STRAIN-COMPENSATED QUANTUM WELLTo reduce the strain accumulated in the InGaAs/GaAsP multilayer structure as close to zero as possible,it is nec-essary to control the thickness and atomic content of each layer with high accuracy.The In composition and thickness of the InGaAs layer has a direct effect on the absorption edge wavelength and the GaAsP layer must be thinned to a satisfactory extent to demonstrate fully the tunnel effect of the barrier layer.Therefore,it is desirable that the average strain of the entire structure is adjusted mainly by the P composition of the GaAsP layer.Meanwhile,for MOVPE,there exists a nonlinear rela-tionship between the P composition of the crystal layer and the P ratio [P/(P ?As)]in the vapor phase precursors,which arises from different absorption and desorption phenomena on the surface.As a result,it is not easy to control the P composition of the crystal layer.To break through such a difficulty and promote efficient optimiza-tion of crystal growth conditions,we have applied a mechanism to evaluate the strain of the crystal layer during growth in real time by sequentially measuring the curvature of wafers during growth with an incident laser beam from the observation window of the reactor.As shown in Fig.7,the wafer curvature during the growth of an InGaAs/GaAsP multilayer structure indicates a periodic behavior.Based on a simple mechanical model,it has become clear that the time changes ofwaferFig.5Distribution of potential formed by the InGaAs/GaAsP strain-compensated multilayer structure:the narrow band-gap InGaAs layer is sandwiched between wide band-gap GaAsP layers and,as a result,it as quantum well-type potential distribution.In the well,electron–hole pairs are formed by absorption of long-wavelength photons and at the same time,recombination of electrons and holes takes place.The team from Solar Quest is focusing on developing a superlattice structure with the thinnest GaAsP barrier layercurvature are proportionate to the strain of the crystal layer relative to a substrate during the growing process.One vibration cycle of the curvature is same as the growth time of an InGaAs and GaAsP pair (Sugiyama et al.2011).Therefore,the observed vibration of the wafer curvature reflects the accumulation of the compression strain that occurs during InGaAs growth and the release of the strain that occurs during GaAsP growth.When the strain is completely compensated,the growth of the InGaAs/GaAsP pair will cause this strain to return to the initial value and the wafer curvature will vibrate with the horizontal line as the center.As shown in Fig.7,strain can be compensated almost completely by adjusting the layer structure.Only by conducting a limited number of test runs,the use of such real-time observation technology of the growth layer enables setting the growth conditions for fabricating the layer structure for which strain has been compensated with highaccuracy.Fig.6Spectral quantum efficiency of GaAs single-junction cell using InGaAs/GaAsP superlattice as theabsorption layer:This structure consists of 60layers of InGaAs quantum wells.The graph also shows data of a reference cell that uses GaAs for its absorption layer (Wang et al.2010,2012)Fig.7Changes in wafer curvature over time during growth of the InGaAs/GaAsP multilayer structure.This graph indicates the measurement result and the simulation result of the curvature based on the layer structure(composition ?thickness)obtained by X-ray diffraction.Since compressive strain is applied during InGaAs growth,the curvature decreases as time passes.On the other hand,since tensile strain is applied during GaAsP growth,the curvature changes in the oppositedirection (Sugiyama et al.2011)FUTURE DIRECTIONSIn order to improve the conversion efficiency by enhancing the current matching of multi-junction solar cells using III–V compound semiconductors,there is an urgent need to create semiconductor materials or structures that can maintain lattice matching with Ge or GaAs,and have a band gap of1.2eV.As for InGaNAs,which consists of InGaAs with several percent of nitrogen added,we have the prospect of extending the band edge to1.0eV while retaining sufficient carrier mobility for solar cells by means of atomic hydrogen irradiation and application of a small quantity of Sb during the growth process.In addition,as for GaNAs bulk crystal containing InAs dots,we were able to extend the band edge to1.2eV and produce a high-quality crystal with enoughfilm thickness to achieve the quantum efficiency equivalent to that of GaAs.These crystals are grown by means of MBE. Therefore,measures that can be used to apply these crys-tals for mass production,such as migration to MOVPE, will be investigated after demonstrating their high effi-ciency by embedding these crystals into multi-junction cells.As for the InGaAs/GaAsP strain-compensated quantum well that can be grown using MOVPE,we are working on the development of a thinner barrier layer while compen-sating for the strain with high accuracy by real-time observation of the wafer curvature.We have had the prospect of achieving a quantum efficiency that will sur-pass existing quantum well solar cells by promoting the carrier transfer within the multilayer quantum well struc-ture using the tunnel effect.As this technology can be transferred quite easily to the existing multi-junction solar cell fabrication process,we strongly believe that this technology can significantly contribute to the efficiency improvement of the latest multi-junction solar cells. REFERENCESOshima,R.,A.Takata,Y.Shoji,K.Akahane,and Y.Okada.2010.InAs/GaNAs strain-compensated quantum dots stacked up to50 layers for use in high-efficiency solar cell.Physica E42: 2757–2760.Sugiyama,M.,K.Sugita,Y.Wang,and Y.Nakano.2011.In situ curvature monitoring for metalorganic vapor phase epitaxy of strain-balanced stacks of InGaAs/GaAsP multiple quantum wells.Journal of Crystal Growth315:1–4.Wang,Y.,Y.Wen,K.Watanabe,M.Sugiyama,and Y.Nakano.2010.InGaAs/GaAsP strain-compensated superlattice solar cell for enhanced spectral response.In Proceedings35th IEEE photovoltaic specialists conference,3383–3385.Wang,Y.P.,S.Ma,M.Sugiyama,and Y.Nakano.2012.Management of highly-strained heterointerface in InGaAs/GaAsP strain-balanced superlattice for photovoltaic application.Journal of Crystal Growth.doi:10.1016/j.jcrysgro.2011.12.049. AUTHOR BIOGRAPHYYoshiaki Nakano(&)is Professor and Director General of Research Center for Advanced Science and Technology,the University of Tokyo.His research interests include physics and fabrication tech-nologies of semiconductor distributed feedback lasers,semiconductor optical modulators/switches,monolithically integrated photonic cir-cuits,and high-efficiency heterostructure solar cells.Address:Research Center for Advanced Science and Technology, The University of Tokyo,4-6-1Komaba,Meguro-ku,Tokyo153-8904,Japan.e-mail:nakano@rcast.u-tokyo.ac.jp。

SOLAR TRACKER FOR ORIENTING SOLAR PANELS

SOLAR TRACKER FOR ORIENTING SOLAR PANELS

专利名称:SOLAR TRACKER FOR ORIENTING SOLAR PANELS发明人:GONZALEZ RODRIGUEZ,ANTONIO,GONZÁLEZ RODRÍGUEZ,Antonio,GONZALEZ RODRIGUEZ, ANGELGASPAR,GONZÁLEZ RODRÍGUEZ, ÁngelGaspar,CAMINERO TORIJA, MIGUELANGEL,CAMINERO TORIJA, MiguelÁngel,CHACON MUNOZ, JESUSMIGUEL,CHACÓN MUÑOZ, JesúsMiguel,GARCIA MARQUEZ, FAUSTOPEDRO,GARCÍA MÁRQUEZ, Fausto Pedro 申请号:ES2009/070349申请日:20090821公开号:WO2011/020931A1公开日:20110224专利内容由知识产权出版社提供专利附图:摘要:The invention relates to a solar tracker (1) for orienting solar panels (2), which rests on a base (3) and comprises a bearing structure (4) for the solar panels (2). The invention comprises an intermediate supporting element (5) to which the panel-bearing structure (4) is hinged. The two movements of the panel-bearing structure (4) are produced respectively by: a) a first mechanism that generates a planar movement, having three movable rigid elements, namely a central element (6) and two lateral elements (7), wherein the lateral rigid elements (7) can move by means of linear actuators (10) and the above-mentioned intermediate supporting element (5) can be placed on one of the movable rigid elements (6, 7) or aligned therewith; and b) a second mechanism that acts on the bearing structure (4) and is located on the intermediate supporting element (5). The invention also comprises means for rotating the bearing structure (4) about a shaft solidly connected to the intermediate supporting element (5).申请人:INDRA SISTEMAS, S.A.,INDRA SISTEMAS, S.A.,GONZALEZ RODRIGUEZ, ANTONIO,GONZÁLEZ RODRÍGUEZ, Antonio,GONZALEZ RODRIGUEZ, ANGEL GASPAR,GONZÁLEZ RODRÍGUEZ, Ángel Gaspar,CAMINERO TORIJA, MIGUELANGEL,CAMINERO TORIJA, Miguel Ángel,CHACON MUNOZ, JESUS MIGUEL,CHACÓN MUÑOZ, Jesús Miguel,GARCIA MARQUEZ, FAUSTO PEDRO,GARCÍA MÁRQUEZ, Fausto Pedro地址:ES,ES,ES,ES,ES,ES国籍:ES,ES,ES,ES,ES,ES代理人:ELZABURU MÁRQUEZ, Alberto更多信息请下载全文后查看。

太阳耀斑的英语

太阳耀斑的英语

太阳耀斑的英语Solar flares are powerful bursts of radiation that are released from the sun's surface and can have significant effects on Earth. They occur when magnetic energy that has built up in the solar atmosphere is suddenly released. This release can result in the production of a large amount of plasma and energetic particles and can cause radiation across the electromagnetic spectrum, from radio waves to X-rays and gamma rays.The intensity of solar flares can vary greatly, with some being relatively mild and others being extremely intense. The most powerful flares are known as X-class flares, and they can cause significant disruptions to radio communications, satellite operations, and even power grids on Earth.One of the key concerns with solar flares is their potential to damage or destroy satellites, which are crucial for various aspects of modern life, including weather forecasting, GPS services, and communication systems. Additionally, the charged particles released during a flare can interact with Earth's magnetic field, causing geomagnetic storms that can lead to auroras at the poles and potentially affect power grids.Scientists study solar flares to better understand their mechanisms and to improve our ability to predict and prepare for their potential impacts. This research is crucial for thedevelopment of technology that can help protect our infrastructure from the effects of solar flares.In summary, solar flares are dynamic and potentially disruptive phenomena that highlight the importance of continued research into solar activity and its effects on our planet. As our reliance on technology grows, understanding and mitigating the risks posed by solar flares becomes increasingly important.。

太阳电池基础

太阳电池基础

P-N结
文字总结:PN结的形成
另一方面,这个电场将使N区的少数载流子空穴向 P区漂移,使P区的少数载流子电子向N区漂移,漂移运 动的方向正好与扩散运动的方向相反。从 N 区漂移到 P 区的空穴补充了原来交界面上 P 区所失去的空穴,从 P 区漂移到 N区的电子补充了原来交界面上 N区所失去的 电子,这就使空间电荷减少,因此,漂移运动的结果是 使空间电荷区变窄。当漂移运动达到和扩散运动相等时, PN 结便处于动态平衡状态。内电场促使少子漂移,阻 止多子扩散。最后,多子的扩散和少子的漂移达到动态 平衡。
简单立方晶格
面心立方晶格 Au、Ag、Cu、Al…
体心立方晶格 Li、Na、K、Fe…
六角密排晶格 Be,Mg,Zn,Cd…
多晶结构
晶界
单晶结构
硅原子结构
硅,一种四价的非金属元素,在自然界分布极广,地壳中
约含27.6%,主要以二氧化硅和硅酸盐的形式存在。 元素符号Si,相对原子量为28.08653,在元素周期表中的 lVA族(第四主族),第三周期。

本征半导体缺点 1、电子浓度=空穴浓度; 2、载流子少,导电性差,温度稳定性差! 不适宜制造半导体器件,通常要掺 入一些杂质来提高导电能力。
杂质半导体
杂质半导体(Impurity Semiconductor):在纯净的半导体 中适当掺入杂质
可提高半导体的导电能力
能改变半导体的导电机制 按导电机制,杂质半导体可分为n型(电子导电)和p型(空 穴导电)两种。
P-N结
PN结的形成
耗尽层 空间电荷区
P
N
在交界面,由于扩散运动, 经过复合,出现空间电荷区。
P-N结
稳定后,n区相对p区有电 势差U0 (n比p高)。p-n 结 也称势垒区。

无机和有机聚合物太阳能电池简介

无机和有机聚合物太阳能电池简介

最高转换效率
制造能耗
成本
材料来源
工艺成熟性
污染
可靠性
块状光伏电池
单晶硅
24.7
最大
最大
丰富
很成熟
最大
最好
多晶硅
18


丰富
成熟


薄膜光伏电池
多晶硅薄膜
16
较小
较小
丰富
比较成熟
较小

非晶硅薄膜
12


丰富
比较成熟
较小
不好
碲化镉
15


比较丰富
比较成熟

一般
铜铟镓硒
19.9


不太丰富
比较成熟
开路电压:VOC 短路电流:ISC 太阳能输入功率: At 为 电池总面积,F(λ) 为在波长人处入射到电池上的每厘米2秒单位带宽的光子数,hc/λ为每个光子的能量 填充因子: 转换效率:
太阳能电池主要参数
无机太阳能电池
块状太阳能电池 单晶硅太阳能电池
N
P
栅线电极
背电极
增透膜
工艺: 单晶硅棒—— 硅片 ——掺杂形成PN结——n结上丝网印刷银浆形成栅线——p结上铝浆烧结制成背电极——栅线表面涂覆增透膜——太阳能电池单体片——太阳电池组件——太阳能电池阵列 结构:
03
光电转换效率偏低, 国际先进水平为10%左右, 且不够稳定, 常有转换效率衰降的现象
02
适合用于建筑光伏一体化以及大型太阳能并网发电系统
砷化镓薄膜太阳能电池
制备方法
晶体生长法、直接拉制法、气相生长法、液相外延法
特点

Resources, Conservation and Recycling

Resources, Conservation and Recycling

Resources,Conservation and Recycling 54 (2010) 1074–1083Contents lists available at ScienceDirectResources,Conservation andRecyclingj o u r n a l h o m e p a g e :w w w.e l s e v i e r.c o m /l o c a t e /r e s c o n r ecPhysical geonomics:Combining the exergy and Hubbert peak analysis for predicting mineral resources depletionAlicia Valero ∗,Antonio ValeroCentre of Research for Energy Resources and Consumptions,CIRCE,University of Zaragoza,María de Luna 3,Zaragoza 50018,Spaina r t i c l e i n f o Article history:Received 14May 2009Received in revised form 19January 2010Accepted 24February 2010Keywords:ExergyHubbert peak ScarcityFuel mineralsNon-fuel mineralsa b s t r a c tThis paper shows how thermodynamics and in particular the exergy analysis can help to assess the degradation degree of earth’s mineral resources.The resources may be physically assessed as its exergy content as well as the exergy required for replacing them from a complete degraded state to the con-ditions in which they are currently presented in nature.In this paper,an analysis of the state of our mineral resources has been accomplished.For that purpose an exergy accounting of 51minerals has been carried out throughout the 20th century.This has allowed estimating from geological data when the peak of production of the main mineral commodities could be reached.The obtained Hubbert’s bell-shaped curves of the mineral and fossil fuels commodities can now be represented in an all-together exergy–time representation here named as the “exergy countdown”.This shows in a very schematic way the amount of exergy resources available in the planet and the possible exhaustion behaviour.Our results show that the peak of production of the most important minerals might be reached before the end of the 21st century.This confirms the Hubbert trend curves for minerals obtained by other authors using a different methodology.These figures may change,as new discoveries are made.However,assuming that these discoveries double,most of the peaks would only displace our concern around 30years.This is due to our exponential demand growth.The exergy analysis of minerals could constitute a universal and transparent tool for the management of the earth’s physical stock.© 2010 Elsevier B.V. All rights reserved.1.IntroductionThe 20th century has been characterized by the economic growth of many industrialized countries.This growth was mainly sustained by the massive extraction and use of the earth’s mineral resources.For instance,only in the US over the span of the last century,the demand for metals grew from a little over 160mil-lion tons to about 3.3billion tons (Morse and Glover,2000).The tendency observed worldwide in the present,is that consumption will continue increasing,especially due to the rapid development of Asia,the desire for a higher living standard of the developing world and the technological progress.But the physical limitations of our planet might seriously restrain world economies.However,inter-national worries are still very far removed from this fact.Currently,most attention is focused rather on the consequences of the use of natural resources,such as climate change,loss of biodiversity or pollution of soils and rivers,than on the depletion of minerals.Obvi-ously the former problems need and are slowly being solved with international agreements,dissemination campaigns,etc.Further-more,the huge amount of energy received every day from the sun (1353J/m 2s)helps restoring at least partially the damages caused∗Corresponding author.E-mail address:aliciavd@unizar.es (A.Valero).to the biosphere,atmosphere and hydrosphere.On the contrary,the natural reposition of the geosphere,which comes mainly from the earth’s interior energy (0.034–0.078J/m 2s—Skinner et al.,1999),is close to zero when compared to that of the other external earth’s spheres.As discussed in Valero and Valero (2010),during millions of years,nature has formed and concentrated minerals through a large number of geological processes such as magmatic separation,hydrothermal,sedimentary,residual,etc.(Chapman and Roberts,1983)forming the currently existing natural stock.The concen-trated mineral deposits serve as a material and fuel reservoir for man.And the more concentrated is a mineral deposit,the less effort is required for extraction.The mining of materials implies an obvious reduction of the natural stock in terms of the min-erals extracted from the mines and the fossil fuels required for the mining processes.Those extracted minerals are concentrated and further refined to obtain the desired raw materials,for which additional quantities of fuels and minerals are required.This way,the natural stock stored in the earth’s crust goes into the hands of society as man-made stock.When the useful life of products finishes,they become dispersed,ending up as wastes (either as pol-lution or disposed of in landfills).As Gordon et al.(2006)argue,the relative sizes of the remaining stock in the lithosphere and the stock transferred to wastes at any given time are measures of how far we have progressed toward the need for total reliance0921-3449/$–see front matter © 2010 Elsevier B.V. All rights reserved.doi:10.1016/j.resconrec.2010.02.010A.Valero,A.Valero/Resources,Conservation and Recycling54 (2010) 1074–10831075on recycling rather than on virgin ore to provide material for new products.Unfortunately,the Second Law of Thermodynamics reflected in Eq.(2),tells us that as the concentration of the resource in the earth’s crust tends to zero,the energy required to extract the min-eral tends to infinity.Consequently,from a practical point of view, it is impossible to recover resources again when they become dis-persed.In a not very distant future,it will be easier to extract metals from landfills than from the crust.This is why recycling is so important to society.But fossil fuels or many additives like Cr,Mo,Mn in steel or in paints,or the new age of high-tech metals such as In,Ge,Ta,etc.included in nanotechnol-ogy and microelectronics are impossible or extremely difficult to recycle.Georgescu-Roegen,1father of ecological economists,states that we can only recycle“carbojunk”.That means that we cannot recycle completely.Furthermore,the worldwide rush for strate-gic materials is causing dramatic consequences in less developed countries such as irreversible environmental damage,corruption and even wars.This effect is named by Humphreys et al.(2007)as the“natural resources curse”.Our technology is quite inefficient in the use of energy and mate-rials,since there is a lack of awareness of the limit.If resources are limited,their management must be carefully planned.But it is impossible to manage efficiently the resources on earth,if we do not know what is available and at which rate it is being depleted.Hence, we need management tools,accountability and political will to accomplish this.The Extractive Industries Transparency Initiative (2006)is becoming an internationally accepted standard for eco-nomic transparency in the oil,gas and mining sectors.But it is still insufficient,since physical and objective information about the remaining resources such as ore grades,quantity of energy and water required for extraction,the amount of waste rock and other physical parameters that would allow an objective analysis of our mineral capital is rarely published.Rational management tools for the efficient use of resources require a theoretical basis,naturally provided by thermodynamics. For a thermodynamicist,this is so obvious,that it is hard to believe that very little systematic effort has been devoted to it.The use of the Second Law through the exergy concept,allows to progress into something more than words.Concepts can be converted into num-bers,and then into objective and universal indicators.The objective of this paper is to contribute to put Second Law numbers to the natural resources depletion and in particular to mineral resources.Georgescu-Roegen was one of thefirst authors in realizing the links between the economic process and the Second Law of thermo-dynamics.In his seminal work The Entropy Law and the Economic Process(Georgescu-Roegen,1971),he states that“the entropy law itself emerges as the most economic in nature of all natural laws[...] and this law is the basis of the economy of life at all levels”.More authors such as Berry et al.(1978),Ruth(1995)or Roma(2006)and Roma and Pirino(2009)state that economic production processes should consider thermodynamic limits on material and energy use in order to be optimal in the long-run.Berry et al.(1978)developed a theorem forfixing the economically-efficient level of thermody-namic efficient production systems.As an example,Ruth(1995) determined the optimal extraction path and production of iron ore at each period of time,taking into account thermodynamic limits on material and energy efficiency,the treatment of technical change through the theory of learning curves and the evaluation of alterna-tive time paths from an economic and thermodynamic perspective. Roma(2006)and Roma and Pirino(2009)developed different mod-els for production processes,imposing energy rather than standard 1See the interview of Antonio Valero with Nicholas Georgescu-Roegen under: http://habitat.aq.upm.es/boletin/n4/aaval.html.monetary terms as a mean of exchange.As a result,the authors state that resources will be more efficiently used,reducing thereby entropic wastes.Parallelly,concerned environmentalists search for alternate indicators closer to nature or social descriptions.A plethora of measuring units(or numeraires)appear,almost one per indica-tor.In particular,those who account for minerals and fossil fuels, have a spectrum of definitions and measurement units that actu-ally impede to make a systematic and universally accepted account of what the earth’s crust provides annually and what remains.On the other side,it is obvious that money cannot be the best unit of measure for the assessment of resources,since currency changes from one country to another,its value depends on dif-ferent factors and moreover,it is impossible to quantify nature in monetary terms,without opening the door to arbitrariness.Nature does not sell anything that we could buy with money.It only can be compensated with counteractions like recovering,restoring and replacing techniques which obviously have an associated cost. These arguments are solid and obvious.However they are difficult to admit,due to the familiarity and omnipresence of money.The argument the cost is not measured with money or everything costs more than the money we pay should be placed over everything can be bought.So,which should be the unit of measure of cost?The answer to this question is in the Second Law of Thermodynamics:if the cost is a sacrifice of resources,and the already consumed resources have been consumed forever,one can deduce that we should see this fact as the base of the physical accountability.In thisfield,Thermody-namics provides tools such as energy,entropy or exergy,among others.The problem with energy is that it does not distinguish quality.Although exergy is also one-dimensional,it is sensible to quantity and quality of the interchanged energy and has energy dimensions.In fact,exergy measures the minimum quantity of use-ful energy required to provide a system for building it from its constituent elements found in the reference environment(R.E.). The reference environment is a hypothetical and homogeneous earth,where all substances have been reacted and mixed,without kinetic or potential energy and at ambient pressure and tempera-ture.Once the R.E.has been defined,the minimum thermodynamic cost or exergy of any material or energyflow can be calculated.This is very important,as exergy takes into account all physical manifes-tations that differentiate the system from its environment:height, velocity,pressure,temperature,chemical composition,concentra-tion,etc.And this is not a function of how much we appreciate things,but on the useful energy that can be released until its deple-tion.On the other hand,the exergy concept participates in all properties of the cost concept:it is additive and can be calculated from the production process.But the process should be considered as reversible in all its steps.The most important contribution of the exergy concept is in its ability to objectify all the physical manifestations in energy units, independently of the economic value.Any product,natural or arti-ficial resource,productive process or polluting emission can be valued from an exergy point of view.This is why a good number of researchers believe that exergy can contribute to the assessment of certain environmental concerns(Szargut,2005,Brodianski,2005, Wall,1977,Sciubba,2003,or Ayres et al.,2004).2.Theoretical backgroundThe most important features thatfix the value of a mineral resource are on one hand its chemical composition and on the other hand its concentration—both characteristics which can be assessed with the single indicator of exergy.1076 A.Valero,A.Valero /Resources,Conservation and Recycling 54 (2010) 1074–1083The chemical composition of a substance is the key factor for fixing the final use of the resource.Furthermore,it has a direct influence on the energy required for processing the mineral (Valero and Valero,2010).For instance,the energy required to extract pure copper from a sulphide is significantly smaller than from an oxide,therefore copper sulphides such as chalcopyrite (CuFeS 2)are pre-ferred as copper ores (see Gerst,2008).The chemical exergy in kJ/mol can be calculated using the following well known expression (Szargut et al.,1988):b ch =v k b 0chel,k+ G mineral(1)where b ch el,k is the standard chemical exergy of the elements that compose the mineral and can be easily found in tables,v k is the number of moles of element k in the mineral and G is the Gibbs free energy of the mineral.The minimum amount of energy –exergy –involved in con-centrating a substance from an ideal mixture of two components is given by the following expression (see for instance Faber and Proops,1991):b c =−RT 0ln(x i )+(1−x i )x iln(1−x i )(2)where b c is the concentration exergy,x i is the molar concentration of substance i,R is the gas constant (8.3145J/mol K)and T 0is the reference temperature (298.15K).The difference between the con-centration exergies obtained with the mineral concentration in a mine x m and with the average concentration in the earth’s crust x c is the minimum energy (kJ/mol)that nature had to spend to bring the minerals from the concentration in the reference state to the concentration in the mine.A more comprehensive expression of the reversible separation energy of an ideal mixture of components is provided by Tsirlin and Titova (2004).In their finite-time thermo-dynamics model,linear kinetics is additionally taken into account.However,in the timeless limit,Tsirlin and Titova’s model converges to Eq.(2).This way,the total replacement exergy (b t —kJ/mol),i.e.its natu-ral exergy,representing the minimum exergy required for restoring the resource from the R.E.to the initial conditions in the mineral deposit,is calculated as the sum of the chemical and concentration exergy components (Eq.(3)).b t =b ch +b c(3)Specific exergies (b t )are converted into absolute exergies (B t )by multiplying the quantities by the moles of the substance con-sidered.However,a study based only on reversible processes (minimum replacement exergies)would ignore technological limits.Results show that,in general,the real energy requirements are tens or even thousands of times greater than the exergy content of the mineral (Valero and Botero,2002).The calculation of the exergy replacement costs b ∗t of the resource,representing the actual exergy required to replace the resource from the R.E.to its initial conditions,with current available technology commonly have two contributions,b ∗t =k ch ·b ch +k c ·b c(4)its chemical cost (k ch ·b ch ),accounting for the chemical produc-tion processes of the substance,and its concentration cost (k c ·b c ),accounting for the concentration processes.Variable k (dimension-less)represents the unit exergy replacement cost of a mineral.It is defined as the relationship between the energy invested in the real obtaining process (E real process )for either refining (k ch )or concen-trating the mineral (k c ),and the minimum energy (exergy)required if the process from the ore to the final product were reversibleTable 1Unit exergy costs of seven base-precious metals (updated from Valero and Botero,2002).Metal k ck ch Ag 7041.81Au 422,879.01Cu 343.180.2Fe 97.4 5.3Ni 431.858.2Pb 218.825.4Zn125.913.2( b mineral ).k =E realprocessb mineral(5)The exergy cost concept developed by Valero et al.(1986)and Lozano and Valero (1993)is also named embodied exergy or cumulative exergy consumption (Szargut et al.,1988).Valero and co-workers focused on the physical roots of cost as well as on pro-viding the concept with a theoretical framework.Table 1shows as an example,the unit exergy replacement costs of some important minerals considered in this paper.These values have been updated by the authors from Valero and Botero (2002).A key study pointing out the actual relationship between ther-modynamic limits and the extraction of mineral resources is that of Chapman and Roberts (1983).These authors developed a com-prehensive treatise on the relationship between the abundance of resources and the energy required to extract them,models for the prediction of non-renewable resource depletion,thermodynamic limits for the exploitation of metals and the effect of recycling on the availability of materials.They observed a relationship between the cut-off ore grade,g ,expressed in weight percentage and the his-torical cumulative production of a given metal,T .This relationship can be expressed as,ln T =−m ln g +c,(6)where c reflects the relative abundance of the metal considered and m the degradation velocity.Values estimated from historical data for constant m can be found in Nguyen and Yamamoto (2007).According to Chapman and Roberts (1983),the energy (approxi-mately equal to its exergy cost b*)required for mining and milling may be expressed as:b ∗=e g(7)where e is the specific energy consumption for mining and milling the metal.A typical value for e is 0.4MJ/kg for open pit mining,and 1.0MJ/kg for underground mining.Eqs.(6)and (7)show empirically what Second Law tells us about the natural exponential behaviour of the exergy needed for extract-ing a material from a mixture as a function of its ore grade (Eq.(2)).The lower the ore grade,the more effort per unit of material is needed to extract it.Even if the earth’s crust is plenty of ele-ments and minerals,its concentration may be so low that the exergy required to extract them from the bare rock becomes economically prohibitive,making it impossible in practice.Following this behaviour,it is natural to resort to the well known Hubbert peak (traditionally used for estimating the peak of produc-tion of fossil fuels—Hubbert (1962))for its application to minerals.Basically,Hubbert (1962)found that the production of fossil fuel trends had a strong family resemblance.The curves started slowly and then rose more steeply tending to increase exponentially with time,until finally an inflection point was reached after it became concave downward.The observed trends are based on the fact that no finite resource can sustain for longer than a brief period such aA.Valero,A.Valero/Resources,Conservation and Recycling54 (2010) 1074–10831077Fig.1.The exergy replacement cost loss of the main non-fuel mineral commodities on earth in the20th century. rate of growth of production;therefore,although production ratestend initially to increase exponentially,physical limits prevent theircontinuing to do so.So for any production curve of afinite resourceoffixed amount,two points on the curve are known at the outset,namely that at t=0and again at t→∞.The production rate will bezero when the reference time is zero,and the rate will again be zerowhen the resource is exhausted,after passing through one or sev-eral maxima.The second consideration is that the area under theproduction curve must equal the quantity of the resource available(R).In this way,the production curve of a certain resource through-out history takes the ideal form of a bell-shaped curve representedby Eq.(8).f(t)=Rb0√e−(t−t0)/b0(8)where parameters b0and t0are the unknowns and R the economic proven reserves of the commodity.The model was successful in predicting the peak of oil extraction in the US lower48states and the subsequent decline in produc-tion.Recently,several authors used Hubbert’s model to predict the evolution of crude oil extraction at the planetary level(Deffeyes, 2001;Bentley,2002;Campbell and Laherrere,1998).According to these estimates,the corresponding production peak could take place within thefirst decade of the21st century or not much later. And as Campbell and Laherrere(1998)argue,from an economic perspective,when the world runs completely out of fuels is not directly relevant:what matters is when production begins to taper off.Beyond that point,prices will rise unless demand declines com-mensurately.Bardi and Pagani(2008)examined the world production of57 minerals reported in the USGS database.They came to the conclu-sion that the bell-shaped curve can be used globally and for most minerals,not only for oil extraction.Moreover,we think that the bell-shaped curve is better suited to minerals,if it isfitted with exergy over time instead of mass pro-duction of the metal commodity over time.Oil quality keeps nearly constant with extraction,whereas other non-fuel minerals do not (mineral’s concentration decreases as the mine is being exploited). Therefore exergy is a much better unit of measure than mass,since it accounts not only for quantity,but also for ore grades and mineral composition.Furthermore,if the Hubbert model is applied to the exergy replacement costs explained before,the technological factor of extracting and refining the mineral is also taken into account.In short,the well known bell-shaped curve can befitted to the exergyor exergy replacement cost consumption data provided,in order to estimate when mineral production will start declining.With our proposal,the yearly exergy replacement cost loss of the commodity calculated with Eq.(5)is represented versus time f(t).With a least squares procedure,the points are adjusted to the curve given by Eq.(8).The maximum of the function is given by parameter t0,and it verifies that f(t0)=R/b0√.3.The exergy loss of world’s mineral reserves in the20th century3.1.Non-fuel mineralsWith the help of historical data compiled by the USGS(2007), and the equations presented above,we have calculated the exergy(B t)and exergy replacement cost(B∗t)destroyed due to non-fuel mineral extraction throughout the20th century of the51most important mineral commodities(see Table2).Furthermore,the average degradation velocities and the latest degradation velocities in minimum exergy and exergy cost terms(˙B t and˙B∗t)registered (from1996to2006)are calculated.The concentration factor has been assumed to be constant and equal to the average ore grades estimated in Valero(2008).Obviously,a better approximation would take into account the evolution of the ore grades with his-tory.But unfortunately this information is generally not compiled and there is only available data for Australia(Mudd,2007).The depletion degree of the commodities shown in Table2(%R and% R.B.)has been obtained as the ratio between the exergy destroyed due to extraction,and the total exergy of the reserves or reserve base of the considered commodity.The latter are obtained as the published reserves or reserve base of the commodity in2006,plus the exergy destroyed from1900to2006.2Finally,the resources to production ratio R/P with exergy units is provided,as a measure of the years until depletion of the commodity.It has been assumed that production remains as in year2006,and that reserves do not increase after that year.****2According to the USGS,reserve base is defined as that part of an identified resource that meets specified minimum physical and chemical criteria related to current mining and production practices,including those for grade,quality,thick-ness,and depth.The reserve basefigure is larger than that of the“reserves”one, which is defined as that part of the reserve base which could be economically extracted or produced at the time of determination.1078 A.Valero,A.Valero/Resources,Conservation and Recycling54 (2010) 1074–1083Table2The exergy and exergy replacement cost loss of the main mineral commodities in the world and average degradation velocities(Valero et al.,2010). Mineral1900–20061996–20062006B t B∗t ˙B t˙B∗t˙B t˙B∗t%R loss%R.B.loss R/P,years R.B./P,yearsAluminium 5.64E+05 1.22E+07 5.27E+03 1.14E+05 1.85E+04 4.01E+0514.912.0135173 Antimony 5.13E+02 5.71E+03 4.80E+00 5.34E+01 1.18E+01 1.31E+0272.856.61632 Arsenic 5.75E+027.23E+03 5.37E+00 6.76E+01 6.91E+008.70E+0174.666.22030 Barite 1.53E+03N.A. 1.43E+01N.A. 3.47E+01N.A.61.025.224111 Beryllium 6.88E−01 3.60E+01 6.43E−03 3.37E−017.97E−03 4.17E−01N.A.N.A.N.A.N.A. Bismuth7.61E+00 1.24E+027.12E−02 1.16E+00 1.54E−01 2.50E+0041.124.756119 Boron oxide 4.04E+03N.A. 3.78E+01N.A. 1.69E+02N.A.39.221.14096 Bromine 2.41E+02N.A. 2.26E+00N.A.7.96E+00N.A.N.A.N.A.N.A.N.A. Cadmium 6.51E+01 3.54E+03 6.08E−01 3.31E+01 1.28E+00 6.98E+0166.845.12562 Cesium 6.62E−02N.A. 6.18E−04N.A.N.A.N.A. 1.20.8N.A.N.A. Chromium 4.53E+04 1.03E+05 4.23E+029.62E+02 1.32E+03 3.00E+03N.A.N.A.N.A.N.A. Cobalt 2.20E+02 1.10E+04 2.05E+00 1.03E+02 5.70E+00 2.86E+0219.511.5104193 Copper 2.96E+04 3.07E+06 2.76E+02 2.87E+047.94E+028.24E+0450.334.53262 Feldspar8.77E+02N.A.8.20E+00N.A. 3.51E+01N.A.N.A.N.A.N.A.N.A. Fluorspar9.95E+03N.A.9.30E+01N.A. 2.03E+02N.A.48.632.14590 Gallium 2.75E−01N.A. 2.57E−03N.A. 1.31E−02N.A.N.A.N.A.N.A.N.A. Germanium 6.52E−01N.A. 6.09E−03N.A. 1.24E−02N.A.N.A.N.A.N.A.N.A. Gold9.98E−018.17E+049.33E−037.64E+02 1.93E−02 1.58E+0375.458.91737 Graphite 3.26E+04N.A. 3.05E+02N.A.7.13E+02N.A.31.015.583204 Gypsum 1.40E+04N.A. 1.30E+02N.A. 3.51E+02N.A.N.A.N.A.N.A.N.A. Helium 1.32E+02N.A. 1.23E+00N.A. 4.11E+00N.A.N.A.N.A.N.A.N.A. Indium 5.45E−01N.A. 5.10E−03N.A. 3.35E−02N.A.34.326.41928 Iodine 1.12E+01N.A. 1.05E−01N.A. 3.86E−01N.A. 3.8 2.26001080 Iron 4.60E+06 3.22E+07 4.30E+04 3.01E+05 1.04E+057.26E+0527.714.984185 Lead 6.01E+03 2.35E+05 5.62E+01 2.19E+038.99E+01 3.51E+0372.555.12349 Lithium9.32E+03 3.49E+048.71E+01 3.26E+02 3.26E+02 1.22E+0362.338.11233 Magnesium 1.01E+04 1.01E+049.45E+019.45E+01 2.96E+02 2.96E+02N.A.N.A.N.A.N.A. Manganese 1.08E+05 1.04E+06 1.01E+039.75E+03 1.82E+03 1.76E+0451.98.739437 Mercury9.24E+00 3.16E+038.63E−02 2.95E+01 2.75E−029.40E+0092.269.431162 Molybdenum9.58E+02 1.80E+048.95E+00 1.68E+02 2.62E+01 4.92E+0237.521.447103 Nickel 4.48E+03 3.55E+05 4.18E+01 3.32E+03 1.31E+02 1.04E+0440.022.94295 Niobium 1.57E+02N.A. 1.46E+00N.A. 6.90E+00N.A.19.818.16167 Phosphate rock 5.47E+047.08E+04 5.12E+02 6.62E+02 1.19E+03 1.54E+0326.111.3127352 PGM 2.41E−01N.A. 2.25E−03N.A.8.35E−03N.A.14.413.0137154 Potash 1.30E+05 2.02E+05 1.22E+03 1.89E+03 2.94E+03 4.56E+0312.8 6.3285619 REE 6.65E+01N.A. 6.22E−01N.A. 2.85E+00N.A. 2.4 1.47151220 Rhenium 6.10E−027.43E+00 5.70E−04 6.95E−02 2.71E−03 3.30E−0124.27.453212 Selenium8.72E+00N.A.8.15E−02N.A. 1.77E−01N.A.48.231.053110 Silver 1.76E+01 1.69E+04 1.65E−01 1.58E+02 3.24E−01 3.11E+0278.563.41328 Strontium 1.83E+03N.A. 1.71E+01N.A.8.52E+01N.A.56.041.91221 Tantalum 4.71E+00 1.31E+03 4.41E−02 1.22E+01 2.30E−01 6.38E+0114.210.794130 Tellurium 4.65E−01N.A. 4.35E−03N.A.7.03E−03N.A.25.813.5159356 Thorium 1.58E+00N.A. 1.47E−02N.A.N.A.N.A. 1.2 1.0N.A.N.A. Tin 2.11E+03 1.08E+05 1.97E+01 1.01E+03 2.92E+01 1.51E+0375.262.72036 Uranium 2.47E+027.29E+04 2.31E+00 6.81E+02 4.68E+00 1.38E+0334.829.996120 Vanadium 4.40E+02 4.96E+03 4.11E+00 4.64E+01 1.56E+01 1.76E+028.9 3.2231675 Wolfram 3.01E+02 2.28E+04 2.81E+00 2.13E+02 6.02E+00 4.56E+0248.530.23269 Zinc 4.98E+049.09E+05 4.65E+028.49E+03 1.13E+03 2.06E+0468.144.41848 Zirconium 3.03E+02 2.91E+05 2.83E+00 2.72E+038.52E+008.18E+0343.829.23261 TOTAL 5.68E+06 5.11E+07 5.31E+04 4.78E+05 1.34E+05 1.29E+0625.614.292191Values are expressed in ktoe and ktoe/year for the degradation velocities.As shown in Table2,in reversible exergy terms,the exergy degradation of the non-fuel mineral capital on earth is clearly dom-inated by the extraction of two commodities:iron and aluminium, representing around81and10%of the total exergy consumption, respectively.The exergy destroyed due to non-fuel mineral extrac-tion between1900and2006is at least5.68Gtoe.As expected, the general consumption pattern has followed an exponential-like behaviour.This is reflected in the drastic change of the exergy degradation velocity(˙B),passing from around10Mtoe/year in 1910,to180Mtoe/year in2006.In irreversible terms,i.e.analyzing the exergy replacement costs (actual exergy)of the commodities,we observe in Fig.1that copper acquires a more important role.Copper is responsible for6%of the total exergy degradation costs on earth,while iron and aluminium, 63and24%,respectively.The irreversible exergy destruction of all analyzed commodities is at least51Gtoe.This means that with current technology,we would require a minimum of a third of all current fuel oil reserves on earth(178Gtoe(BP,2007))for the replacement of all depleted non-fuel mineral commodities. Excluding iron and aluminium,which eclipse the rest commodi-ties,we observe in Fig.2that in decreasing order,the production of manganese,zinc,nickel,zirconium,lead,chromium,uranium, tin and gold contribute also significantly to the planet’s non-fuel mineral capital degradation.Again,an exponential behaviour of the exergy costs of all commodities is observed.The average exergy cost degradation velocity in the20th century is at least0.5Gtoe/year.However in the last decade,this velocity increased to1.3Gtoe/year.According to the depletion ratios(%R loss and%R.B.loss)in Table2,man has depleted in just one century around26%of its world non-fuel mineral reserves,and around14%of its reserve base. The estimated years until the depletion of the total reserves and reserve base are around92and191years,respectively.It must be pointed out that these are only minimum numbers,as it has been。

从邵逸夫天文奖看中国天文

从邵逸夫天文奖看中国天文

2007 我们的差距:
2008
1. 科学思想: 没有看到这个方向的重要性
2009
2. 光谱仪(ELODIE was an echelle type spectrograph installed at
the Observatoire de Haute-Provence 1.93m reflector in south-eastern
重申我在2009国际天文年对 中国天文发展的二点建议
走国际化天文发展道路
大力发展大学天文
祝王先生双寿万福
祝福贺上门 王老九十旬 先辈树丰碑 生平献天文 双节迎寿庆 寿比南山高 万世永吉祥 福如东海深
陈建生 敬贺于壬辰年
郑民
我担任评审工作的八年(2004-2011)中, 观测研究得奖的有五项:
地面光学观测三项 2008 Reinhard Genzel – Black Hole
VLT + 第一流台址+ 自适应
我们的差距: 1. 没有好台址 2. 没有大望远镜(10米级) 3. 没有观测时间相对专用的小望远镜(2-4米) 4. 缺高效率的附属设备 5. 空间望远镜空白 6. 缺原创重大科学思想 7. 缺理论大师 8. 天文队伍的量与质上有较大差距 9. 缺10年磨一剑的持续性、系统性 10.没有融入国际天文
我国在天体物理理论方面与国际上的差距还很大, 对天体物理的深刻理解 原创性思想 系统性
我担任评审工作的八年(2004-2011)中, 观测研究得奖的有五项,其中空间观测二项
2010 Charles L Bennett, Lyman A Page Jr and David Spergel – WMAP 2011 Enrico Costa and Gerald J Fishman – GRB

太阳动力学天文台

太阳动力学天文台

探测卫星
探测卫星
在SDO这个探测器之前,美国宇航局曾在1995年发射了太阳与太阳风层探测器(SOHO),这架探测器最初计 划的运行时间是两年,后来持续延长,以期能够覆盖太阳活动的11年周期。实际上过去15年里我们看到的多数太 空中拍摄的太阳照片都来自SOHO。SDO是美国宇航局“与日同在”计划中发射的第一颗探测器,“与日同在”计 划的目标是理解太阳这颗磁场变化的恒星,测量其对地球上的生活和社会的影响。另一架目前运行中的太阳探测 器是美国宇航局2006年发射的日地关系天文台(STEREO),它能够与SOHO一起从三个角度拍摄太阳的立体图像。 日地关系天文台与SOHO一起能够更加准确地计算出日冕物质抛射的方向和抵达地球的时间。
当地时间2022年10月26日晚间,美国国家航空航天局(NASA)的太阳动力学天文台用卫星捕捉到了一张照片, 看起来仿佛太阳在“微笑”,但“微笑”的背后可能预示着一场太阳风暴,有可能导致地磁暴袭击地球。
功能特点
功能特点
科学家希望能预知太阳活动并为之做出积极准备。
1、太阳动力学天文望远镜为地球传回相当于普通高清电视10倍高清度的太阳图像。使用远紫外光,每0.75 秒的可拍一张照片。
任务介绍
任务介绍
太阳动力学天文台(Solar Dynamics Observatory, SDO)是美国国家航空航天局一个观测太阳至少5年的 太空任务。本卫星是在2010年2月11日发射。SDO是美国国家航空航天局观测日地关系的“Living With a Star (LWS)”计划的一部分。LWS计划的目的是要更加了解太阳和地球的关系。SDO的科学目标是以小尺度的时间和 空间下以多波段研究太阳大气层,以了解太阳对地球和近地球太空区域的影响。预期SDO将能研究太阳的磁场如 何产生以及磁场结构、如何储存电磁能量与能量如何以太阳风、高能粒子和多种波长的辐射等形式释放进太阳圈 和外太空。

astronomy天文学 英语英文小演讲

astronomy天文学 英语英文小演讲

Galileo
Newton Harley
Kepler
Explore the universe is the eternal human desire
armillary sphere Dengfeng Stargazing sets(观星台) (观星台) 浑仪
Located in henan dengfeng, built in the early yuan dynasty.It’s China's earliest existing observatory
蟹状星云 (SN1054) nebula
射电
光学(HST)
蓝色:X-ray 红色:光学
Solar eclipse(日食)
In china……
The night fell in the day…
What happened and what will happen in china these years. • • • • • • • • 2008年8月1日日全食 2009年7月22日日全食 2010年1月15日日环食 2012年5月21日日环食 Annular eclipse 2020年6月21日日环食 2030年6月1日日环食 2034年3月20日日全食 2035年9月2日日全食
There is a good new that this year an Annular eclipse will go through china We can even image how amazing it will be
But the bad new is that it won’t go through shanghai….
Now we know the main objects in the universe is staБайду номын сангаасs(恒星) and nebulae(星云), because they have great quality
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Industry Report Green TechnologyJeffrey Bencik,CFA 212-292-8134 jbencik@Solar Rays-Weekly Industry Data Points•Weekly Market Performance(9/24/10-10/01/10).U.S.solar-based stocks(AMAT,ESLR, FSLR,SOLR,SPWRA,WFR)were up an average of470bps last week in comparison to the S&P500,which was down20bps.Evergreen Solar,Inc.(ESLR)was the outlier of the group, up21%.The company announced it had hired a new president and CEO earlier in the week. Overall,solar stocks remained relatively positive.We are on the forefront of earnings and continue to have a positive outlook considering industry demand,major project completions and announcements as it relates to further industry growth.Our2011global solar demand forecast of17.7GW may prove conservative.•Chinese solar stocks(CSIQ,CSUN,JASO,LDK,SOLF,STP,TSL,YGE)outperformed U.S. solar stocks as the group was up5.3%vs.4.7%.LDK was one of the top performers,as the stock increased14.7%.We believe the good performance was likely tied to the financing announcement by the China Development Bank Corp.(CDB)of RMB60billion,roughly US $9billion,last week.YGE was also up significantly by10.3%.The company announced the completion of the NFL's largest solar power system,which is attractive from a media standpoint but not meaningful to earnings.•High Short Interest Could Provide Upside.The solar industry continues to be a high beta space,even though the industry as a whole has not recovered as well as the overall market. Importantly,the industry has significantly reduced its costs and is reaching grid parity ex-subsidies in several regions of the world.We expect this trend to continue and as subsidies become less important toward driving sales,the industry could see a revaluation toward higher multiples.While we do not expect this in the near term,there continues to be a high level of short interest in the solar shares,that could drive a short squeeze and a rapid revaluation of the shares.Interestingly,as Exhibit1shows,the U.S.solar stocks are at a significantly higher short interest level in comparison to the Chinese solar stock(14.6%vs.6.4%,respectively).SunPower is at the highest level at24%,followed closely by Applied Materials at21%.Suntech and LDK Solar are the two most shorted Chinese stocks at around 10%of float.The most likely reason for the higher level of short interest is the fact that the U.S.-based companies have larger market caps and can be shorted more easily.Taken together,the solar industry is currently short at roughly10%of the outstanding float.This is down slightly from a peak of12%but within the same short interest range of the past year.October5,2010TECHNOLOGYDelSolar and IBM Sign Joint Agreement to Develop Solar Cell TechnologyDelSolar Co.,Ltd(3599.TW)announced it has signed an agreement to jointly develop compound thin film solar cells with IBM(NYSE:IBM)aimed to surpass next-generation thin film solar cell technology and result in commercial production.The collaboration includes leveraging DelSolar's existing expertise in photovoltaic("PV")technology and process as well as IBM's advanced semiconductor technology and materials science know-how.Source:DelSolar Co.Ltd. PROJECTSSunPower and Etrion Complete Sale of Italian Power PlantsSunPower Corp.(NASDAQ:SPWRA,SPWRB)announced that Etrion Corporation(TSX:ETX),an independent solar power producer,has completed the previously announced definitive sale and purchase agreements to acquire the equity in the first two phases of Montalto di Castro solar park, Italy's largest solar photovoltaic(PV)power park,for approximately€49million.The acquisition of the20-megawatt(MW)first phase of the project was completed in August and the acquisition of the 8MW second phase was completed last week.SunPower will recognize the sale of the first phase of the project as a return of capital,and will recognize revenue on the sale of the second phase, including previously deferred engineering,procurement and construction(EPC)revenue.Media Advisory:Enbridge Announces Grand Opening of the Largest Photovoltaic Facility in the WorldEnbridge Inc.(TSX:ENB)(NYSE:ENB)and First Solar,Inc.(NASDAQ:FSLR)have completed the expansion of the Sarnia Solar Project from20megawatts of capacity to80megawatts(MW)making it the largest operating photovoltaic facility in the world.Source:Enbridge Inc.and First Solar,Inc. New York Jets and Yingli Solar Announce Completion of NFL's Largest Solar Power System at Team HeadquartersYingli Green Energy Holding Company Limited(NYSE:YGE),which holds the brand"Yingli Solar," and The New York Jets announced the completion of a solar power system at the Jets'team headquarters and training center in Florham Park,NJ.This is the largest photovoltaic(PV) installation at a NFL team headquarters,utilizing over3,000Yingli Solar panels.Source:Yingli Green Energy.ACQUISITIONS&INVESTMENTSUnderwriters Exercise Overallotment Option for650,000GT Solar Shares in Secondary OfferingGT Solar International,Inc.(NASDAQ:SOLR),announced that the underwriters for the recently announced secondary offering of GT Solar common stock have exercised in part their over-allotment option to purchase an additional650,000shares of GT Solar's common stock.The 11,650,000shares of GT Solar common stock in the secondary offering,including the650,000 shares subject to the over-allotment option,were sold at a price to the public of$7.39per share. Source:GT Solar Inc.COMPANY&MARKET NEWSEvergreen Solar Appoints Michael El-Hillow President and Chief Executive Officer Evergreen Solar,Inc.(NasdaqGM:ESLR)announced that it has appointed Michael El-Hillow to the position of president and CEO effective immediately,replacing Richard M.Feldt who has accepted the position of Chief Executive Officer with a privately held company.The company will immediately begin a search for a Chief Financial Officer.Paul Kawa,corporate controller,will serve as interim Chief Financial Officer.Source:Evergreen Solar Inc.California Municipal Utilities Association Applauds ARB Adoption of a33%Renewable Energy Requirement by2020The California Municipal Utilities Association(CMUA)applauds the California Air Resources Board (CARB)for its adoption of a requirement that utilities and other electricity providers get a minimum of 33%of their power from renewable energy sources by2020.Source:California Municipal Utilities Commission.Solarbuzz Defines U.K.Photovoltaic Market Opportunity as Demand AcceleratesThe solar photovoltaic(PV)feed-in tariff(FiT)program introduced by the United Kingdom in April 2010has catapulted the U.K.into the mainstream of global PV market activity.According to the results of the Solarbuzz®U.K.PV Market2010report issued,the U.K.'s emergence could not be better timed,when taking into account the uncertain prospects for the dominant German market next year.With FiTs as high as41.3pence per kWh paid over25years,the foundations are in place for rampant PV market growth ernment incentives yield immediate installed PV system Internal Rates of Return between8%and11%over the next12months.Despite this,the U.K. market is already exposed to significant potential policy risks—more so than most other European markets—even though the FiT is only six months old.Source:Solarbuzz LLC.IMS Research:PV Cell Capacity Continues To Climb But Margins Will Fall in2011 Annualized PV cell production capacity increased once again in2Q10,reaching over25GW according to a recent report from IMS Research.IMS Research forecasts that capacity will reach33 GW by the end of the year,over80%of which will be for crystalline cell technologies and warns that gross margins will fall in2011.Megawatt shipments of PV modules grew15%in the second quarter of2010over1Q10according to IMS Research's latest market report.This growth marked six consecutive quarters of increasing shipments and took total modules shipped for the first half of the year to over8GW,only slightly less than the whole of2009.Revenues generated by PV modules in the same period amounted to over$15billion.Source:IMS Research.Solar Market Keeps Shining in2011Despite extreme shifts in pricing,demand and governmental subsidies,the global photovoltaic market in2011will experience robust growth,with installations rising by42.3%for the year, according to the market research firm iSuppli Corp.iSuppli forecasts that worldwide solar installations will reach20.2Gigawatts(GW)next year,up from14.2GW at the end of2010. Germany,the world's leading Photovoltaic(PV)market,will continue to play a key role and account for half of the total installations,at9.5GW.While an impressive growth total for the year,the expansion will be down significantly from the97.9%increase in2009.Source:iSuppli Corporation.Exhibit1:Average Short InterestExhibit2:Solar Stock Weekly Performance(9/24/10-10/01/10)Ticker Close Change% Change Short Interest$ -0.2%$ (2.43)S&P 5001,146.24$ 0.7%21.43%$ 0.08AMAT11.71$ 0.13$ 21.3%9.68% ESLR0.74$ 0.1%13.66%$ 0.14FSLR147.23$ 0.31$ 3.9%8.93% SOLR8.32$ 0.12$ 0.9%24.05% SPWRA14.06$ 1.4%9.62% WFR11.96$ 0.17Average US Solar 4.7%14.6% CSUN 4.40$ 0.9% 4.11%$ 0.04$ 4.5% 6.93% JASO8.68$ 0.37$ 14.7%10.29% LDK10.15$ 1.30$ 4.0% 1.58%$ 0.48SOL12.35$ 4.3% 4.90% SOLF12.61$ 0.52$ -2.6%10.56%$ (0.25)STP9.25$ 6.4% 5.69%$ 1.78TSL29.46$ 10.3%7.07%$ 1.25YGE13.39Average Chinese Solar 5.3% 6.4% Source: Thomson One, BloombergExhibit3:Global Solar Demand ForecastsAnnual Installations (MW)20032004200520062007200820092010E2011E% Market Germany6038638301103150538008500700040% Italy571370197700115015008% US101103145207342475900200011% Japan2722902872102304846509005% Czech Republic0003504116005503% Spain1124985912671605608505% China4710204730055010006% France571113441854008505% Canada572755503% Belgium01217502923004002% Korea352143274992005003% Portugal100145060901501% India45122040501253002% Australia7810121330752001% Israel751501% ROW861001641692462203508005% Total5941102142016032492575972231480017700100% Growth85.5%28.9%12.9%55.5%131.1%25.4%104.9%19.6%CAGR52.9%Cumulative Installations20032004200520062007200820092010E2011EGermany1034189727273830533591351763524635Spain21451437343405346540254875Japan11321422170919192149263332834183US3764796248311173164825484548Italy313850120318101821683668China6370801001474479971997Korea91435783524516511151France263344571012866861536Portugal3331868128218368India1419315190140265565Czech Republic01145446510651615Belgium22422713636631063Australia5261708396126201401Israel75225ROW11341233139915651812203223823182Total389753176920941215171223373686254012Growth36.4%30.1%36.0%61.2%47.2%65.0%46.5%Source: SEIA, EPIA, Photon International, Kaufman Brothers, L.P.Rating and Price Target Historyhttps:///charts/large/AMAT.pnghttps:///charts/large/ESLR.pnghttps:///charts/large/FSLR.pnghttps:///charts/large/JASO.pnghttps:///charts/large/LDK.pnghttps:///charts/large/SOLR.pnghttps:///charts/large/SPWRA.pnghttps:///charts/large/WFR.pngGuide to Kaufman Bros.Ratings-Distribution and Definitions*IB Serv./Past12Mos. Rating Count Percent Count Percent BUY[B]3959.1000.00 HOLD[H]2436.4028.33 SELL[S]3 4.5000.00BUY:We believe the stock will outperform its peer group over the next12months due to superior fundamentals and/or positive catalysts.HOLD:We believe the stock will perform in line with its peer group over the next12months due to full valuation and/or lack of catalysts.SELL:We believe the stock will underperform its peer group over the next12months due to overvaluation,deteriorating fundamentals,and/or negative near-term catalysts.*Excludes stocks with ratings under review.Analyst CertificationI,Jeffrey Bencik,CFA,hereby certify that the views expressed in this research report accurately reflect my personal views about any and all of the subject securities or issuers referred to in this document.Furthermore,no part of my compensation was,is or will be,directly or indirectly,related to the specific recommendation or views expressed in this report. Research DisclosuresKaufman Bros.,L.P.makes a market in AMAT.Kaufman Bros.,L.P.makes a market in ESLR.Kaufman Bros.,L.P.makes a market in FSLR.Kaufman Bros.,L.P.makes a market in SOLR.Kaufman Bros.,L.P.makes a market in SPWRA.DisclaimersThis report is for informative purposes only.Under no circumstances is it to be construed as an offer to sell or a solicitation to buy any security.The information contained herein has been obtained from sources believed to be reliable,but its accuracy and completeness,and that of the opinions based thereon,are not guaranteed.Kaufman Bros.,L.P.,its affiliates and subsidiaries,and/or its officers and employees may from time to time acquire,hold,or sell a position in the securities mentioned herein.Kaufman Bros.,L.P.may also perform investment banking or other services for,or solicit investment banking or other business from,any company mentioned in this report.The analyst(s)responsible for preparing this report may receive compensation based upon various factors including the firm's overall profitability,a portion of which is derived from investment banking revenues.Our equity research product is deemed to be a consulting service.Valuation MethodologyKaufman Bros.,L.P.,methodology for valuation analysis,including the assigning of ratings and price targets,may take into account many factors including,but not restricted to,the following:market capitalization,maturity of business,volatility of business and security,analyses of market risk,growth rate,revenue stream,discounted cash flow(DCF),EBITDA,EPS,cash flow(CF),EV/EBITDA,P/E,PE/growth,P/CF,P/FCF,premium(discount)/average group EV/EBITDA,premium (discount)/average group P/E,sum of the parts,net asset value,dividend returns,and return on equity(ROE)over the next12months.Risk Relating to Our Price Target and RatingThe financial instruments discussed in this report will not be suitable for all investors and should generally be viewed as speculative.Investors must make their own financial decisions based upon their specific investment objectives and financial situation.Past performance of the financial instruments discussed in this report should not be taken as an indication of future results.The price,value of and income from any of the financial instruments mentioned in this report can rise as well as fall and could be affected by many factors including but not limited to changes in economic,financial and political factors, competitive dynamics,and any event that impacts the company being discussed including overall market conditions.If a financial instrument is denominated by a currency other than the investor's home currency,fluctuations in exchange rates could adversely affect the price of,value of or income derived from the financial instruments described in this report.In addition,investors in securities whose values are affected by the currency of the underlying security,effectively assume currency risk.©2010KAUFMAN BROS.,L.P.All rights reserved.Reproduction without permission is prohibited.Additional information available upon request.。

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