Simulation Study of a Positive Ionospheric Storm Phase Observed at Millstone Hill

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关于生态模拟的英文作文

关于生态模拟的英文作文Ecological Simulations: Unlocking Nature's Secrets.In the intricate tapestry of life, understanding the complex interactions within ecosystems is paramount. Ecological simulations have emerged as a powerful tool, providing scientists with the ability to probe the veiled mechanisms that govern the natural world.Delving into the Virtual Realm.Ecological simulations are computational models that mimic real-world ecosystems. They recreate the intricate network of species interactions, environmental variables, and ecological processes that shape the dynamics of nature. By manipulating virtual environments, researchers can test hypotheses, predict outcomes, and explore scenarios that may be difficult or impossible to observe in the field.Unveiling Hidden Relationships.One of the primary strengths of ecological simulations lies in their ability to uncover hidden relationships and patterns within ecosystems. By eliminating the noise and confounding factors present in real-world observations, simulations allow researchers to isolate and examine specific interactions. This process enables the identification of key drivers of ecosystem functioning and the prediction of how changes in one component may cascade through the entire system.Predicting Future Trajectories.Ecological simulations play a crucial role in forecasting the future trajectories of ecosystems under various scenarios. By incorporating data on environmental stressors, climate change, and land-use patterns, models can project how these factors will impact species distributions, community composition, and ecosystem services. This predictive power is invaluable for conservation efforts, enabling policymakers to develop strategies that mitigate negative impacts and promoteresilience.Evaluating Management Strategies.Ecological simulations serve as a testing ground for evaluating different management strategies. Before implementing changes in the field, researchers can simulate various scenarios to assess their potential consequences. By comparing outcomes under different approaches, managers can identify the most effective interventions for achieving specific conservation or restoration goals.Unveiling Complexity and Variability.Ecological simulations highlight the inherent complexity and variability of natural systems. By representing the stochasticity and non-linearity present in nature, models can capture emergent phenomena that may not be apparent from simple observations. This realism enhances the predictive power of simulations and provides a more accurate representation of ecosystem dynamics.Collaboration and Open Science.The advancement of ecological simulations relies heavily on collaboration and open science practices. Researchers share data, models, and code to foster transparency and reproducibility. This collaborative approach ensures that models are rigorously tested and refined, leading to more robust and reliable results.Challenges and Limitations.Despite their immense value, ecological simulations also face challenges and limitations. Data collection for model parameterization can be time-consuming and expensive. Additionally, models may oversimplify complex ecological processes or fail to capture the full range of interactions present in real-world ecosystems. Ongoing research and model refinements are necessary to address theselimitations and enhance the accuracy and realism of simulations.Conclusion.Ecological simulations have revolutionized the study of ecosystems, providing unprecedented insights into their intricate dynamics and future trajectories. By harnessing computational power, scientists can uncover hidden relationships, predict ecological outcomes, and inform conservation and management strategies. As models continueto evolve and become more sophisticated, the potential for ecological simulations to advance our understanding of nature and guide our stewardship of the planet is limitless.。

积极心理学英文综述范文

积极心理学英文综述范文Title: A Comprehensive Review of Positive Psychology.Positive psychology, a branch of psychology that focuses on the study and promotion of positive emotions, strengths, virtues, and well-being, has emerged as a significant field of research in recent decades. Developed by Martin Seligman and his colleagues in the late 1990s, positive psychology aims to shift the focus of psychology from pathology and deficit-based approaches to the study of human strengths, talents, and positive emotions. This review aims to provide a comprehensive overview of positive psychology, its key concepts, applications, and future directions.Origins and Definition.Positive psychology has its roots in the humanistic tradition of psychology, which emphasizes the importance of human potential and growth. It is distinct from traditionalpsychology, which has often been focused on studying and treating mental illness and pathology. Positive psychology instead focuses on the positive aspects of human life, including emotions, traits, and institutions that promote well-being and flourishing.The core principles of positive psychology are centered around three key areas: positive emotions, engagement with life, and positive relationships. Positive emotions refer to feelings of happiness, joy, contentment, and other positive affective states. Engagement with life involves being fully present and immersed in activities that are personally meaningful and fulfilling. Positiverelationships refer to the quality and nature of our social connections with others, including family, friends, and community.Applications and Interventions.Positive psychology has a wide range of applications and interventions that aim to promote positive outcomes and enhance well-being. One of the most well-knowninterventions in positive psychology is the practice of gratitude, which involves intentionally focusing on and appreciating the good things in life. Gratitude has been shown to improve emotional well-being,增强人际关系, and enhance overall life satisfaction.Other interventions include mindfulness practices, such as meditation and yoga, which promote awareness and engagement with the present moment. Mindfulness has been found to reduce stress and anxiety, enhance emotional regulation, and improve cognitive performance. Other positive psychology interventions focus on building social connections, fostering positive relationships, and developing character strengths.Future Directions.Positive psychology is a rapidly growing field, and there are many exciting directions for future research and application. One area of particular interest is the development of positive interventions for specific populations, such as adolescents, older adults, andindividuals with mental health conditions. By tailoring interventions to meet the unique needs of these populations, positive psychology has the potential to make significant contributions to improving their well-being and quality of life.Another important direction for future research is the exploration of the neurobiological mechanisms that underlie positive emotions and well-being. By understanding how positive psychology interventions work at theneurobiological level, we can gain a deeper understandingof their effectiveness and develop more targeted andprecise interventions.Conclusion.Positive psychology has emerged as a critical field of research and practice that focuses on the positive aspectsof human life. By studying and promoting positive emotions, strengths, virtues, and well-being, positive psychology has the potential to transform individuals, communities, and society for the better. Future research and applications inpositive psychology will continue to expand our understanding of human potential and growth and lead to more effective interventions that promote positive outcomes and enhance well-being.。

2024新课标1卷英语

1.What is the main idea of the passage?A.The history of technology.B.The impact of social media.C.The benefits of exercise.（答案）D.The challenges of modern education.2.Which word best describes the author's tone in the text?A.SarcasticB.Optimistic（答案）C.PessimisticD.Neutral3.What does the phrase "in the long run" mean in the context?A.ImmediatelyB.Eventually（答案）C.OccasionallyD.Rarely4.According to the passage, what is the most effective way to learn a new language?A.Watching foreign movies.B.Listening to music in that language.C.Practicing with a language tutor.（答案）D.Reading books translated into that language.5.Why did the scientist decide to conduct the experiment?A.To prove a previous theory wrong.B.To discover a new element.C.To test a new hypothesis.（答案）D.To replicate a famous study.6.What is the purpose of the author writing this article?A.To entertain readers with a story.B.To persuade readers to adopt a new habit.（答案）C.To inform readers about a recent event.D.To analyze a complex issue.7.Which of the following is NOT mentioned in the passage as a cause of climate change?A.DeforestationB.OverpopulationC.Increased use of renewable energy（答案）D.Industrial emissions8.What can be inferred from the last sentence of the passage?A.The problem will never be solved.B.More research is needed.（答案）C.The solution is simple and straightforward.D.The author is uncertain about the future.。

沸腾数值模拟

During the last decades, numerous experimental and numerical investigations have been carried out to analyze the thermal characteristics and ﬂow patterns in ﬂow boiling. The typical air–water two-phase ﬂow patterns encountered in conventional vertical tubes are bubbly ﬂow, slug ﬂow, churn ﬂow and annular ﬂow. Most
Simulation of boiling ﬂow in evaporator of separate type heat pipe with low heat ﬂux
Y.W. Kuang, Wen Wang ⇑, Rui Zhuan, C.C. Yi
School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
abstract
The separate type heat pipe heat exchanger is considered to be a potential selection for developing passive cooling spent fuel pool – for the passive pressurized water reactor. This paper simulates the boiling ﬂow behavior in the evaporator of separate type heat pipe, consisting of a bundle of tubes of inner diameter 65 mm. It displays two-phase characteristic in the evaporation section of the heat pipe working in low heat ﬂux. In this study, the two-phase ﬂow model in the evaporation section of the separate type heat pipe is presented. The volume of ﬂuid (VOF) model is used to consider the interaction between the ammonia gas and liquid. The ﬂow patterns and ﬂow behaviors are studied and the agitated bubbly ﬂow, churn bubbly ﬂow are obtained, the slug bubble is likely to break into churn slug or churn froth ﬂow. In addition, study on the heat transfer coefﬁcients indicates that the nucleate boiling is the dominant mechanism in large pipes at low mass and heat ﬂux, with the heat transfer coefﬁcient being less sensitive to the total mass ﬂux.

高二英语心理学原理探究单选题40题

高二英语心理学原理探究单选题40题1.The student's fear of public speaking can be an example of _____.A.phobiaB.anxietyC.depressionD.stress答案：A。

本题考查心理学名词的理解。

选项A“phobia”意为恐惧症，学生对公开演讲的恐惧可以被视为一种特定的恐惧症。

选项B“anxiety”焦虑通常较为宽泛，不一定特指对特定事物的恐惧。

选项C“depression”抑郁症主要表现为长期的情绪低落等，与对公开演讲的恐惧不符。

选项D“stress”压力，可以由多种情况引起，但与特定的恐惧也不同。

2.When a person always feels sad and hopeless, it might be a sign of _____.A.maniaB.schizophreniaC.depressionD.anorexia答案：C。

选项A“mania”躁狂症，主要表现为情绪高涨等。

选项B“schizophrenia”精神分裂症，有多种复杂症状，与总是感到悲伤和绝望不同。

选项C“depression”抑郁症的主要症状之一就是长期感到悲伤和绝望。

选项D“anorexia”厌食症，主要与饮食问题相关。

3.A person who has a strong need for order and routine may have traits of _____.A.OCDB.PTSDC.ADHDD.bipolar disorder答案：A。

选项A“OCD”强迫症，患者通常有对秩序和常规的强烈需求。

选项B“PTSD”创伤后应激障碍，主要由创伤事件引起。

选项C“ADHD”注意缺陷多动障碍，表现为注意力不集中等。

选项D“bipolar disorder”双相情感障碍，有情绪的大幅波动。

4.The tendency to remember positive events more than negative ones is called _____.A.confirmation biasB.rosy retrospectionC.selective memoryD.optimism bias答案：B。

体外试验模拟肾结石溶解治疗的反应动力学

化学溶石方法由来已久，是针对泌尿系结石的一种不容忽视的治疗方式，有其独特优势。

溶解液通过与结石成分化学反应，使结石成分重新溶解在液相中，随着液体被带出体外。

由于液体的流动性和溶液成分的可扩散性，较各种手术手段更容易到达肾脏的各个角落，不容易有治疗死角，因而处理结石更加彻底、干净。

随着现代泌尿外科微创技术的发展，各种内镜技术的成熟，包括肾造瘘管、输尿管导管、双J 管、导尿管在内的各种常规导管形成的通路成为术后溶石治疗的理想平台，使溶石治疗能够方便地与外科治疗相结合。

因而，化学溶石治疗的应用前景更加明朗。

笔者［1］前期已针对溶石溶液的成分进行了一定的基础研究，改进了磷酸盐结石溶解液的成分，仿照经典的Suby 氏液配制了以乳酸、α酮戊二酸为主要成分的两种溶解溶液，并证实新溶解液较经典溶液的溶解效率明显提高。

然而，新溶液的临床应用任重道远，尚面临许多未解决的现实问题。

首先是灌注溶石的过程采用何种速度的问题。

按照反应的一般规律，如果灌注速度过高，溶液从结石表面快速流过，还没来及充分反应就脱离了反应界面，浪费溶液。

此外灌注速度过高可能会导致肾盂压力升高而导致患者不适或溶液吸收，发生危险。

如果灌注过慢，虽然反应深度较好，溶液利用率较高，但产物带走慢，阻碍反应进行，溶解效率将较低。

此外人体尿液产生的速度相对恒定，灌注速度慢的情况下，相对而言尿液对溶解液的稀释作用将更为严重，溶解效率会进一步降低。

如果溶解效率太低将丧失临床治疗的现实可能性。

灌流过快或过慢均有明显弊端，因而采用合适的灌流速度是结石溶解治疗的需要解决的一个重要问题。

查阅既往文献，各学者采用的灌流速度并不相同，临床常用流量为100~120mL/h ，但之前的文献中并未说明原因，也查阅不到关于确定灌流速度的相关文献。

为了解决上述问题，阐明结石溶解doi ：10.3969/j.issn.1006⁃5725.2017.16.022基金项目：中山市科技计划项目基金资助（编号：2014A1FC120）作者单位：528415广东省中山市，南方医科大学附属小榄医院泌尿外科体外试验模拟肾结石溶解治疗的反应动力学张劲勍杨增士叶宁卓红兵沈勇虎林豪胜李刚【摘要】目的探索结石溶解溶液在模拟人体环境下溶解结石过程中的反应动力学规律，为临床应用提供参考。

divergence detected in AMG solver pressure correction,fluent典型错误

问题：8-31-rke-steady-4-0.8运行至11000迭代步是报错“divergence detected in AMG solver: pressure correction”（补充：每个工况均遇到此类情况，原因尚未找到，暂时解决办法是将压力松弛因子从0.3改为0.1）；解答：This error is reported when Fluent is not able to converge the solution。

The residuals are not converged。

This error may come due to various reasons like improper mesh，improper boundary conditions，wrong material and improper solution settings。

It is advisable to re check the entire case when one encounters this error。

以上老外对这个问题的回复，确实很多客户遇到过这样的问题，原因是多方面的，主要原因集中在网格质量差和边界条件的不合理。

对于你的问题，如果之前都没有错误，到一定计算步才出现这样的问题，说明不是边条的问题，问题可能出在局部的网格上面，你将压力松弛因子调小，增加跌代次数，减小了误差，是解决问题的方法之一。

如果想彻底回避这样的问题出现，建议在网格上还需要下点工夫！附：老外对类似问题的回复，你可以参考一下。

I try to study the turbulence inside a vertical cylinder. In a first time, I take the case of steady flow. The air is introduced axially from below, deflected by means of a small conical deflector and thanks to the geometry of the chamber the air goes up into the cylinder. I take the ideal gas law, k-epsilon model, inlet and outlet pressure for boundary conditions. My problem is that I have directly the message "divergence detected in AMG solver : k when I want to iterate. I try a lot of solutions I have find in this forum without any result. Could anyone help me? Thanksin advance Check your hardware, especially RAM sockets. I have experience, that this could be initiated by some bad memory address sectors.I had a similar problem, but with pressure correction. I found that I had some highly skewed cells. Once I corrected the highly skewed cells by adapting theiso-values of cell skewness my case began to iterate.Perhaps this may be your problem. First initialize the solution and then go to contours grid and select equiangle skew and click compute to get you min and maxs. Having skewed cells of 0.9 or higher isn';t good, as in my case.Hope this helps I have check the skewed cells but it appears that in my case, this number is lower than 0.4 Is it too high?Hi. I have a simulation of a supersonic-valve running but the program shows me this message: divergence detected in AMG solver: temperature I tried to rise the limits for temperature and other solution limits but nothing has helped so far Does anyone what to do thanksTry to use more conservative Under-relaxation factor. I had the same problem with a wing in a transonic flight. According to me the segregated solver is not suitable for the conditions with high compressibility. Let me know if you succeed in using the segregated and how...I suggest using the coupled solver，Your problem will vanish... Hope to hear good news from you soon.Luca this will be something wrong with the either boundary condition or with model selection, generally if things are right fluent just converges fine without any warning or problem.in my opinion these are the signs that you are doing something wrong in setting up the case, look closelyHi, I have the same problem, and couldn't solve it by using the coupled solver. Is there any other possible way. I am simulating office room problem. It seems very simple but on every stage it is creating problems for me. I am going to try to change the underrelaxation. lets see what comes up.Thanks long ago, one of my friend was doing CFD analysis of a kitchen,, using coupled solver, and he faced the same problem, for some time he d idn’t get the converged results. Finally when I looked at his mesh. It seemed the problem is with the mesh not with the solver settings. I suggested him to make mesh more finer, and viola it gave results in one run, without any problem. so moral of the story check your mesh.My mesh is quite fine, but I will try more finer mesh. Thanks then it shall converge ..anyway have you tried using segregated solver, how the results with that Error: Divergence detected in AMG solver? Posted By: frank Date: Sun, 16 Jan 2005, 3:58 p.m. What does mean and how do i fix it? I am runing a rosseland radiation model and it wont run past 1 iteration.Frank you are using the segregated solver, so you must reduce the under relaxation factor as you can. You could have a grid issue concerning high skewness. This can be checked by going to contours grid cell equiangle skew and select compute and check the min and max. You should be below 0.9. If over then this could be your problem. It has happened to me a couple of times. thanks a million i will try this...frank AMG solver: k divergence? Posted By: Robert Date: Sun, 9 Mar 2003,11:23 a.m. How do I remedy a divergence with this message. This is for scramjet combustion in 2D with injectors on both the top and bottom. Is there any way to look up error messages?reduce underalaxtion factor.I have tried reducing the underelaxation factors but the divergence persists. Any other suggestions? Perhaps in the AMG solver Menu? It looks like a problem with your boundary conditions, be sure they're compatible with each other and consistent with the physics of what you';re trying to simulate, I think you'd better don't touch anything in the AMG menu, unless you know exactly what you're doing, It is my opinion, if this could help.请求高手指点：循环流化床中非稳态气固两相流计算，使用欧拉双流体模型，K-E湍流模型，网格质量<0.55。

专八英语阅读

英语专业八级考试TEM-8阅读理解练习册（1）(英语专业2012级)UNIT 1Text AEvery minute of every day, what ecologist生态学家James Carlton calls a global ―conveyor belt‖, redistributes ocean organisms生物.It’s planetwide biological disruption生物的破坏that scientists have barely begun to understand.Dr. Carlton —an oceanographer at Williams College in Williamstown,Mass.—explains that, at any given moment, ―There are several thousand marine species traveling… in the ballast water of ships.‖ These creatures move from coastal waters where they fit into the local web of life to places where some of them could tear that web apart. This is the larger dimension of the infamous无耻的，邪恶的invasion of fish-destroying, pipe-clogging zebra mussels有斑马纹的贻贝.Such voracious贪婪的invaders at least make their presence known. What concerns Carlton and his fellow marine ecologists is the lack of knowledge about the hundreds of alien invaders that quietly enter coastal waters around the world every day. Many of them probably just die out. Some benignly亲切地，仁慈地—or even beneficially — join the local scene. But some will make trouble.In one sense, this is an old story. Organisms have ridden ships for centuries. They have clung to hulls and come along with cargo. What’s new is the scale and speed of the migrations made possible by the massive volume of ship-ballast water压载水— taken in to provide ship stability—continuously moving around the world…Ships load up with ballast water and its inhabitants in coastal waters of one port and dump the ballast in another port that may be thousands of kilometers away. A single load can run to hundreds of gallons. Some larger ships take on as much as 40 million gallons. The creatures that come along tend to be in their larva free-floating stage. When discharged排出in alien waters they can mature into crabs, jellyfish水母, slugs鼻涕虫，蛞蝓, and many other forms.Since the problem involves coastal species, simply banning ballast dumps in coastal waters would, in theory, solve it. Coastal organisms in ballast water that is flushed into midocean would not survive. Such a ban has worked for North American Inland Waterway. But it would be hard to enforce it worldwide. Heating ballast water or straining it should also halt the species spread. But before any such worldwide regulations were imposed, scientists would need a clearer view of what is going on.The continuous shuffling洗牌of marine organisms has changed the biology of the sea on a global scale. It can have devastating effects as in the case of the American comb jellyfish that recently invaded the Black Sea. It has destroyed that sea’s anchovy鳀鱼fishery by eating anchovy eggs. It may soon spread to western and northern European waters.The maritime nations that created the biological ―conveyor belt‖ should support a coordinated international effort to find out what is going on and what should be done about it. (456 words)1.According to Dr. Carlton, ocean organism‟s are_______.A.being moved to new environmentsB.destroying the planetC.succumbing to the zebra musselD.developing alien characteristics2.Oceanographers海洋学家are concerned because_________.A.their knowledge of this phenomenon is limitedB.they believe the oceans are dyingC.they fear an invasion from outer-spaceD.they have identified thousands of alien webs3.According to marine ecologists, transplanted marinespecies____________.A.may upset the ecosystems of coastal watersB.are all compatible with one anotherC.can only survive in their home watersD.sometimes disrupt shipping lanes4.The identified cause of the problem is_______.A.the rapidity with which larvae matureB. a common practice of the shipping industryC. a centuries old speciesD.the world wide movement of ocean currents5.The article suggests that a solution to the problem__________.A.is unlikely to be identifiedB.must precede further researchC.is hypothetically假设地，假想地easyD.will limit global shippingText BNew …Endangered‟ List Targets Many US RiversIt is hard to think of a major natural resource or pollution issue in North America today that does not affect rivers.Farm chemical runoff残渣, industrial waste, urban storm sewers, sewage treatment, mining, logging, grazing放牧,military bases, residential and business development, hydropower水力发电,loss of wetlands. The list goes on.Legislation like the Clean Water Act and Wild and Scenic Rivers Act have provided some protection, but threats continue.The Environmental Protection Agency (EPA) reported yesterday that an assessment of 642,000 miles of rivers and streams showed 34 percent in less than good condition. In a major study of the Clean Water Act, the Natural Resources Defense Council last fall reported that poison runoff impairs损害more than 125,000 miles of rivers.More recently, the NRDC and Izaak Walton League warned that pollution and loss of wetlands—made worse by last year’s flooding—is degrading恶化the Mississippi River ecosystem.On Tuesday, the conservation group保护组织American Rivers issued its annual list of 10 ―endangered‖ and 20 ―threatened‖ rivers in 32 states, the District of Colombia, and Canada.At the top of the list is the Clarks Fork of the Yellowstone River, whereCanadian mining firms plan to build a 74-acre英亩reservoir水库，蓄水池as part of a gold mine less than three miles from Yellowstone National Park. The reservoir would hold the runoff from the sulfuric acid 硫酸used to extract gold from crushed rock.―In the event this tailings pond failed, the impact to th e greater Yellowstone ecosystem would be cataclysmic大变动的，灾难性的and the damage irreversible不可逆转的.‖ Sen. Max Baucus of Montana, chairman of the Environment and Public Works Committee, wrote to Noranda Minerals Inc., an owner of the ― New World Mine‖.Last fall, an EPA official expressed concern about the mine and its potential impact, especially the plastic-lined storage reservoir. ― I am unaware of any studies evaluating how a tailings pond尾矿池，残渣池could be maintained to ensure its structural integrity forev er,‖ said Stephen Hoffman, chief of the EPA’s Mining Waste Section. ―It is my opinion that underwater disposal of tailings at New World may present a potentially significant threat to human health and the environment.‖The results of an environmental-impact statement, now being drafted by the Forest Service and Montana Department of State Lands, could determine the mine’s future…In its recent proposal to reauthorize the Clean Water Act, the Clinton administration noted ―dramatically improved water quality since 1972,‖ when the act was passed. But it also reported that 30 percent of riverscontinue to be degraded, mainly by silt泥沙and nutrients from farm and urban runoff, combined sewer overflows, and municipal sewage城市污水. Bottom sediments沉积物are contaminated污染in more than 1,000 waterways, the administration reported in releasing its proposal in January. Between 60 and 80 percent of riparian corridors (riverbank lands) have been degraded.As with endangered species and their habitats in forests and deserts, the complexity of ecosystems is seen in rivers and the effects of development----beyond the obvious threats of industrial pollution, municipal waste, and in-stream diversions改道to slake消除the thirst of new communities in dry regions like the Southwes t…While there are many political hurdles障碍ahead, reauthorization of the Clean Water Act this year holds promise for US rivers. Rep. Norm Mineta of California, who chairs the House Committee overseeing the bill, calls it ―probably the most important env ironmental legislation this Congress will enact.‖ (553 words)6.According to the passage, the Clean Water Act______.A.has been ineffectiveB.will definitely be renewedC.has never been evaluatedD.was enacted some 30 years ago7.“Endangered” rivers are _________.A.catalogued annuallyB.less polluted than ―threatened rivers‖C.caused by floodingD.adjacent to large cities8.The “cataclysmic” event referred to in paragraph eight would be__________.A. fortuitous偶然的，意外的B. adventitious外加的，偶然的C. catastrophicD. precarious不稳定的，危险的9. The owners of the New World Mine appear to be______.A. ecologically aware of the impact of miningB. determined to construct a safe tailings pondC. indifferent to the concerns voiced by the EPAD. willing to relocate operations10. The passage conveys the impression that_______.A. Canadians are disinterested in natural resourcesB. private and public environmental groups aboundC. river banks are erodingD. the majority of US rivers are in poor conditionText CA classic series of experiments to determine the effects ofoverpopulation on communities of rats was reported in February of 1962 in an article in Scientific American. The experiments were conducted by a psychologist, John B. Calhoun and his associates. In each of these experiments, an equal number of male and female adult rats were placed in an enclosure and given an adequate supply of food, water, and other necessities. The rat populations were allowed to increase. Calhoun knew from experience approximately how many rats could live in the enclosures without experiencing stress due to overcrowding. He allowed the population to increase to approximately twice this number. Then he stabilized the population by removing offspring that were not dependent on their mothers. He and his associates then carefully observed and recorded behavior in these overpopulated communities. At the end of their experiments, Calhoun and his associates were able to conclude that overcrowding causes a breakdown in the normal social relationships among rats, a kind of social disease. The rats in the experiments did not follow the same patterns of behavior as rats would in a community without overcrowding.The females in the rat population were the most seriously affected by the high population density: They showed deviant异常的maternal behavior; they did not behave as mother rats normally do. In fact, many of the pups幼兽，幼崽, as rat babies are called, died as a result of poor maternal care. For example, mothers sometimes abandoned their pups,and, without their mothers' care, the pups died. Under normal conditions, a mother rat would not leave her pups alone to die. However, the experiments verified that in overpopulated communities, mother rats do not behave normally. Their behavior may be considered pathologically 病理上，病理学地diseased.The dominant males in the rat population were the least affected by overpopulation. Each of these strong males claimed an area of the enclosure as his own. Therefore, these individuals did not experience the overcrowding in the same way as the other rats did. The fact that the dominant males had adequate space in which to live may explain why they were not as seriously affected by overpopulation as the other rats. However, dominant males did behave pathologically at times. Their antisocial behavior consisted of attacks on weaker male,female, and immature rats. This deviant behavior showed that even though the dominant males had enough living space, they too were affected by the general overcrowding in the enclosure.Non-dominant males in the experimental rat communities also exhibited deviant social behavior. Some withdrew completely; they moved very little and ate and drank at times when the other rats were sleeping in order to avoid contact with them. Other non-dominant males were hyperactive; they were much more active than is normal, chasing other rats and fighting each other. This segment of the rat population, likeall the other parts, was affected by the overpopulation.The behavior of the non-dominant males and of the other components of the rat population has parallels in human behavior. People in densely populated areas exhibit deviant behavior similar to that of the rats in Calhoun's experiments. In large urban areas such as New York City, London, Mexican City, and Cairo, there are abandoned children. There are cruel, powerful individuals, both men and women. There are also people who withdraw and people who become hyperactive. The quantity of other forms of social pathology such as murder, rape, and robbery also frequently occur in densely populated human communities. Is the principal cause of these disorders overpopulation? Calhoun’s experiments suggest that it might be. In any case, social scientists and city planners have been influenced by the results of this series of experiments.11. Paragraph l is organized according to__________.A. reasonsB. descriptionC. examplesD. definition12．Calhoun stabilized the rat population_________.A. when it was double the number that could live in the enclosure without stressB. by removing young ratsC. at a constant number of adult rats in the enclosureD. all of the above are correct13.W hich of the following inferences CANNOT be made from theinformation inPara. 1?A. Calhoun's experiment is still considered important today.B. Overpopulation causes pathological behavior in rat populations.C. Stress does not occur in rat communities unless there is overcrowding.D. Calhoun had experimented with rats before.14. Which of the following behavior didn‟t happen in this experiment?A. All the male rats exhibited pathological behavior.B. Mother rats abandoned their pups.C. Female rats showed deviant maternal behavior.D. Mother rats left their rat babies alone.15. The main idea of the paragraph three is that __________.A. dominant males had adequate living spaceB. dominant males were not as seriously affected by overcrowding as the otherratsC. dominant males attacked weaker ratsD. the strongest males are always able to adapt to bad conditionsText DThe first mention of slavery in the statutes法令，法规of the English colonies of North America does not occur until after 1660—some forty years after the importation of the first Black people. Lest we think that existed in fact before it did in law, Oscar and Mary Handlin assure us, that the status of B lack people down to the 1660’s was that of servants. A critique批判of the Handlins’ interpretation of why legal slavery did not appear until the 1660’s suggests that assumptions about the relation between slavery and racial prejudice should be reexamined, and that explanation for the different treatment of Black slaves in North and South America should be expanded.The Handlins explain the appearance of legal slavery by arguing that, during the 1660’s, the position of white servants was improving relative to that of black servants. Thus, the Handlins contend, Black and White servants, heretofore treated alike, each attained a different status. There are, however, important objections to this argument. First, the Handlins cannot adequately demonstrate that t he White servant’s position was improving, during and after the 1660’s; several acts of the Maryland and Virginia legislatures indicate otherwise. Another flaw in the Handlins’ interpretation is their assumption that prior to the establishment of legal slavery there was no discrimination against Black people. It is true that before the 1660’s Black people were rarely called slaves. But this shouldnot overshadow evidence from the 1630’s on that points to racial discrimination without using the term slavery. Such discrimination sometimes stopped short of lifetime servitude or inherited status—the two attributes of true slavery—yet in other cases it included both. The Handlins’ argument excludes the real possibility that Black people in the English colonies were never treated as the equals of White people.The possibility has important ramifications后果，影响.If from the outset Black people were discriminated against, then legal slavery should be viewed as a reflection and an extension of racial prejudice rather than, as many historians including the Handlins have argued, the cause of prejudice. In addition, the existence of discrimination before the advent of legal slavery offers a further explanation for the harsher treatment of Black slaves in North than in South America. Freyre and Tannenbaum have rightly argued that the lack of certain traditions in North America—such as a Roman conception of slavery and a Roman Catholic emphasis on equality— explains why the treatment of Black slaves was more severe there than in the Spanish and Portuguese colonies of South America. But this cannot be the whole explanation since it is merely negative, based only on a lack of something. A more compelling令人信服的explanation is that the early and sometimes extreme racial discrimination in the English colonies helped determine the particular nature of the slavery that followed. (462 words)16. Which of the following is the most logical inference to be drawn from the passage about the effects of “several acts of the Maryland and Virginia legislatures” (Para.2) passed during and after the 1660‟s?A. The acts negatively affected the pre-1660’s position of Black as wellas of White servants.B. The acts had the effect of impairing rather than improving theposition of White servants relative to what it had been before the 1660’s.C. The acts had a different effect on the position of white servants thandid many of the acts passed during this time by the legislatures of other colonies.D. The acts, at the very least, caused the position of White servants toremain no better than it had been before the 1660’s.17. With which of the following statements regarding the status ofBlack people in the English colonies of North America before the 1660‟s would the author be LEAST likely to agree?A. Although black people were not legally considered to be slaves,they were often called slaves.B. Although subject to some discrimination, black people had a higherlegal status than they did after the 1660’s.C. Although sometimes subject to lifetime servitude, black peoplewere not legally considered to be slaves.D. Although often not treated the same as White people, black people,like many white people, possessed the legal status of servants.18. According to the passage, the Handlins have argued which of thefollowing about the relationship between racial prejudice and the institution of legal slavery in the English colonies of North America?A. Racial prejudice and the institution of slavery arose simultaneously.B. Racial prejudice most often the form of the imposition of inheritedstatus, one of the attributes of slavery.C. The source of racial prejudice was the institution of slavery.D. Because of the influence of the Roman Catholic Church, racialprejudice sometimes did not result in slavery.19. The passage suggests that the existence of a Roman conception ofslavery in Spanish and Portuguese colonies had the effect of _________.A. extending rather than causing racial prejudice in these coloniesB. hastening the legalization of slavery in these colonies.C. mitigating some of the conditions of slavery for black people in these coloniesD. delaying the introduction of slavery into the English colonies20. The author considers the explanation put forward by Freyre andTannenbaum for the treatment accorded B lack slaves in the English colonies of North America to be _____________.A. ambitious but misguidedB. valid有根据的but limitedC. popular but suspectD. anachronistic过时的，时代错误的and controversialUNIT 2Text AThe sea lay like an unbroken mirror all around the pine-girt, lonely shores of Orr’s Island. Tall, kingly spruce s wore their regal王室的crowns of cones high in air, sparkling with diamonds of clear exuded gum流出的树胶; vast old hemlocks铁杉of primeval原始的growth stood darkling in their forest shadows, their branches hung with long hoary moss久远的青苔;while feathery larches羽毛般的落叶松,turned to brilliant gold by autumn frosts, lighted up the darker shadows of the evergreens. It was one of those hazy朦胧的, calm, dissolving days of Indian summer, when everything is so quiet that the fainest kiss of the wave on the beach can be heard, and white clouds seem to faint into the blue of the sky, and soft swathing一长条bands of violet vapor make all earth look dreamy, and give to the sharp, clear-cut outlines of the northern landscape all those mysteries of light and shade which impart such tenderness to Italian scenery.The funeral was over,--- the tread鞋底的花纹/ 踏of many feet, bearing the heavy burden of two broken lives, had been to the lonely graveyard, and had come back again,--- each footstep lighter and more unconstrained不受拘束的as each one went his way from the great old tragedy of Death to the common cheerful of Life.The solemn black clock stood swaying with its eternal ―tick-tock, tick-tock,‖ in the kitchen of the brown house on Orr’s Island. There was there that sense of a stillness that can be felt,---such as settles down on a dwelling住处when any of its inmates have passed through its doors for the last time, to go whence they shall not return. The best room was shut up and darkened, with only so much light as could fall through a little heart-shaped hole in the window-shutter,---for except on solemn visits, or prayer-meetings or weddings, or funerals, that room formed no part of the daily family scenery.The kitchen was clean and ample, hearth灶台, and oven on one side, and rows of old-fashioned splint-bottomed chairs against the wall. A table scoured to snowy whiteness, and a little work-stand whereon lay the Bible, the Missionary Herald, and the Weekly Christian Mirror, before named, formed the principal furniture. One feature, however, must not be forgotten, ---a great sea-chest水手用的储物箱,which had been the companion of Zephaniah through all the countries of the earth. Old, and battered破旧的，磨损的, and unsightly难看的it looked, yet report said that there was good store within which men for the most part respect more than anything else; and, indeed it proved often when a deed of grace was to be done--- when a woman was suddenly made a widow in a coast gale大风，狂风, or a fishing-smack小渔船was run down in the fogs off the banks, leaving in some neighboring cottage a family of orphans,---in all such cases, the opening of this sea-chest was an event of good omen 预兆to the bereaved丧亲者;for Zephaniah had a large heart and a large hand, and was apt有…的倾向to take it out full of silver dollars when once it went in. So the ark of the covenant约柜could not have been looked on with more reverence崇敬than the neighbours usually showed to Captain Pennel’s sea-chest.1. The author describes Orr‟s Island in a(n)______way.A.emotionally appealing, imaginativeB.rational, logically preciseC.factually detailed, objectiveD.vague, uncertain2.According to the passage, the “best room”_____.A.has its many windows boarded upB.has had the furniture removedC.is used only on formal and ceremonious occasionsD.is the busiest room in the house3.From the description of the kitchen we can infer that thehouse belongs to people who_____.A.never have guestsB.like modern appliancesC.are probably religiousD.dislike housework4.The passage implies that_______.A.few people attended the funeralB.fishing is a secure vocationC.the island is densely populatedD.the house belonged to the deceased5.From the description of Zephaniah we can see thathe_________.A.was physically a very big manB.preferred the lonely life of a sailorC.always stayed at homeD.was frugal and saved a lotText BBasic to any understanding of Canada in the 20 years after the Second World War is the country' s impressive population growth. For every three Canadians in 1945, there were over five in 1966. In September 1966 Canada's population passed the 20 million mark. Most of this surging growth came from natural increase. The depression of the 1930s and the war had held back marriages, and the catching-up process began after 1945. The baby boom continued through the decade of the 1950s, producing a population increase of nearly fifteen percent in the five years from 1951 to 1956. This rate of increase had been exceeded only once before in Canada's history, in the decade before 1911 when the prairies were being settled. Undoubtedly, the good economic conditions of the 1950s supported a growth in the population, but the expansion also derived from a trend toward earlier marriages and an increase in the average size of families; In 1957 the Canadian birth rate stood at 28 per thousand, one of the highest in the world. After the peak year of 1957, thebirth rate in Canada began to decline. It continued falling until in 1966 it stood at the lowest level in 25 years. Partly this decline reflected the low level of births during the depression and the war, but it was also caused by changes in Canadian society. Young people were staying at school longer, more women were working; young married couples were buying automobiles or houses before starting families; rising living standards were cutting down the size of families. It appeared that Canada was once more falling in step with the trend toward smaller families that had occurred all through theWestern world since the time of the Industrial Revolution. Although the growth in Canada’s population had slowed down by 1966 (the cent), another increase in the first half of the 1960s was only nine percent), another large population wave was coming over the horizon. It would be composed of the children of the children who were born during the period of the high birth rate prior to 1957.6. What does the passage mainly discuss?A. Educational changes in Canadian society.B. Canada during the Second World War.C. Population trends in postwar Canada.D. Standards of living in Canada.7. According to the passage, when did Canada's baby boom begin?A. In the decade after 1911.B. After 1945.C. During the depression of the 1930s.D. In 1966.8. The author suggests that in Canada during the 1950s____________.A. the urban population decreased rapidlyB. fewer people marriedC. economic conditions were poorD. the birth rate was very high9. When was the birth rate in Canada at its lowest postwar level?A. 1966.B. 1957.C. 1956.D. 1951.10. The author mentions all of the following as causes of declines inpopulation growth after 1957 EXCEPT_________________.A. people being better educatedB. people getting married earlierC. better standards of livingD. couples buying houses11.I t can be inferred from the passage that before the IndustrialRevolution_______________.A. families were largerB. population statistics were unreliableC. the population grew steadilyD. economic conditions were badText CI was just a boy when my father brought me to Harlem for the first time, almost 50 years ago. We stayed at the hotel Theresa, a grand brick structure at 125th Street and Seventh avenue. Once, in the hotel restaurant, my father pointed out Joe Louis. He even got Mr. Brown, the hotel manager, to introduce me to him, a bit punchy强力的but still champ焦急as fast as I was concerned.Much has changed since then. Business and real estate are booming. Some say a new renaissance is under way. Others decry责难what they see as outside forces running roughshod肆意践踏over the old Harlem. New York meant Harlem to me, and as a young man I visited it whenever I could. But many of my old haunts are gone. The Theresa shut down in 1966. National chains that once ignored Harlem now anticipate yuppie money and want pieces of this prime Manhattan real estate. So here I am on a hot August afternoon, sitting in a Starbucks that two years ago opened a block away from the Theresa, snatching抓取，攫取at memories between sips of high-priced coffee. I am about to open up a piece of the old Harlem---the New York Amsterdam News---when a tourist。

carry out a simulation study to

carry out a simulation study toSimulation studies are a valuable tool for understanding complex systems and processes, especially when it's not possible or practical to conduct real-world experiments. A simulation study can help to answer a variety of research questions by replicating the conditions of a real-world scenario in a controlled environment.To carry out a simulation study, you need to follow these general steps:Define the research question: Start by clarifying the purpose of your simulation study. What do you hope to learn by simulating this system or process? Identify the key variables and parameters that will be part of your simulation.Select the appropriate simulation software: There are various simulation software packages available, such as MATLAB, Simulink, or Python-based packages like SimPy or DEAP. Choose one that suits your needs and has the capabilities to handle your specific simulation requirements.Build the simulation model: Based on your research question, construct a mathematical model that represents the system or process you're simulating. This model should capture the essential features and dynamics of the system while abstracting away unnecessary details. Parameterize the model: Specify the values for the variables andparameters in your model. Collect data or make assumptions about these values based on prior knowledge or real-world observations.Run the simulation: Program the simulation using the selected software and execute it to generate results. The software will iteratively update the state of the system according to the defined rules and parameters. Analyze and interpret the results: Examine the data generated by the simulation, looking for patterns, trends, or other insights. Compare these findings with predictions or expectations based on your research question. Validate the results by comparing them with existing literature or real-world data if available.Draw conclusions: Draw conclusions from your analysis, answering your research question and addressing any limitations of your study. Use these insights to inform future research or provide practical guidance for decision-making in related fields.Communicate the findings: Share your results with others through presentations, reports, or academic publications. Provide a clear explanation of your methods, results, and their relevance to the field you're studying.Remember that the quality of your simulation study depends on the validity and realism of your model, as well as the choice of appropriate software and techniques for simulating your system or process.。

Problems on electrorheological fluid flows

PROBLEMS ON ELECTRORHEOLOGICAL FLUID FLOWS.
R.H.W. HOPPE, W.G. LITVINOV ¨ ANGEWANDTE ANALYSIS MIT SCHWERPUNKT NUMERIK LEHRSTUHL FUR ¨ AUGSBURG, UNIVERSITATSSTRASSE, ¨ UNIVERSITAT 14 86159 AUGSBURG, GERMANY
k −2 2 k −1 2
2 where |ε|2 = n i,j =1 εij , n being the dimension of a domain of ﬂow, γ1 − γ4 , are constants, and k is a function of |E |2 . The constants γ1 − γ4 and the function k are determined by the approximation of ﬂow curves which are obtained experimentally for diﬀerent values of the vector of electric ﬁeld E (see Subsection 2.2). But the conditions of coerciveness and monotonicity of the operator − div(σ + pI1 ) impose severe constraints on the constants γ1 − γ4 and on the function k, see [20], such that with these restrictions one cannot obtain a good approximation of a ﬂow curve, to say nothing of approximation of a set of ﬂow curves corresponding to diﬀerent values of E .

昆明2024年05版小学K卷英语第4单元暑期作业(含答案)

昆明2024年05版小学英语第4单元暑期作业(含答案)考试时间：90分钟（总分:110）A卷考试人：_________题号一二三四五总分得分一、综合题(共计100题共100分)1. 听力题：I see a _____ (大象) at the zoo.2. 填空题：Ancient Mesopotamia is often called the "cradle of _______." (文明)3. salinity) of seawater affects marine life. 填空题：The ____4. 听力题：I can ________ my bike to school.5. 听力题：In a chemical equation, the substances that react are called ______.6. 选择题：What is the chemical symbol for gold?A. AuB. AgC. FeD. Hg答案:A7. 听力题：The symbol for copper is _____.8. 听力题：I can ______ (swim) really well.9. 填空题：The ancient Romans created a network of ______ (道路) that connected their empire.My _____ (小猫) likes to climb trees.11. 听力题：The atmosphere protects the Earth from harmful ______ rays.12. sustainability report) evaluates progress. 填空题：The ____13. 听力题：They are ___ a song. (singing)14. 听力题：Acids are proton ______.15. 听力题：I love eating ___. (fruit)16. 填空题：我的朋友喜欢 _______ (活动). 她觉得这很 _______ (形容词)17. 选择题：What do we call the protective covering of the human body?A. SkinB. HairC. BonesD. Muscles18. 听力题：A ______ has a unique pattern on its fur.19. 填空题：The __________ is the capital of the United Kingdom. (伦敦)20. 听力题：A ______ is a chemical substance that speeds up a reaction.21. 填空题：I play video games with my ____.22. 听力题：The ancient Sumerians are credited with creating one of the first _______ systems.23. 填空题：The _____ (种植者) shares tips on how to care for plants.The ancient Greeks valued ________ (艺术和哲学).25. 听力题：The movie was ___ (exciting/boring).26. 选择题：What is the capital city of the USA?A. New YorkB. Washington, D.C.C. Los AngelesD. Chicago答案:B27. 听力题：A chemical reaction that releases heat is called an ________ reaction.28. 听力题：The armadillo rolls into a _____.29. 选择题：What do you call the process of growing plants?A. FarmingB. GardeningC. AgricultureD. All of the above答案:D30. 选择题：How many players are on a football team?A. 10B. 11C. 12D. 1331. 听力题：We eat breakfast in the ___. (kitchen)32. 选择题：What do we call the layer of gases surrounding the Earth?A. TroposphereB. AtmosphereC. StratosphereD. Exosphere答案: BWhat do we call a baby dog?A. KittenB. PuppyC. CalfD. Chick34. 填空题：My cousin is a great __________ (志愿者).35. 听力题：A balanced chemical equation shows the conservation of ______.36. 填空题：My teacher is very __________ (公平).37. 填空题：My ________ (玩具名称) is a source of inspiration.38. 选择题：What do you call the number of days in a week?A. FiveB. SixC. SevenD. Eight答案: C39. 填空题：The sun is ________ (灿烂) today.40. 选择题：What is the name of the famous singer known as the "King of Pop"?A. Elvis PresleyB. Michael JacksonC. PrinceD. Madonna41. 填空题：I love to ______ (尝试) new hobbies.42. 选择题：How many legs does a spider have?A. SixB. EightC. FourD. Ten答案:B43. 听力题：I can ________ my own lunch.44. 听力题：An electric generator converts mechanical energy into ______ energy.45. 填空题：Cats can be very ______.46. 填空题：The country known for the Eiffel Tower is ________ (法国).47. 听力题：The _____ (car/bike) is parked outside.48. 填空题：My sister loves to play with her __________. (玩具)49. 选择题：What is the name of the fairy tale character who had a red hood?A. CinderellaB. Sleeping BeautyC. Little Red Riding HoodD. Snow White答案: C50. 听力题：The candy is ___ (sticky).51. 填空题：The ancient Greeks valued _____ and knowledge.52. (World) Health Organization was established in 1948. 填空题：The ____53. 填空题：My friend has a unique __________ (视角) on life.54. 选择题：What do we call the process of taking in air?A. InhalationB. ExhalationC. BreathingD. Respiration答案: A55. 听力题：The unit of measure for chemical concentration is ______ per liter.56. 选择题：What do we call the time it takes for the Earth to rotate once on its axis?A. YearB. MonthC. DayD. Hour答案:C. Day57. 听力题：Cacti store _______ in their stems.58. 填空题：A _______ (金鱼) can live for many years.59. 填空题：The country with the highest mountain is ________ (拥有最高山峰的国家是________).60. 选择题：What do you call a large body of freshwater?A. SeaB. OceanC. LakeD. River答案:C61. 选择题：Which color is a stop sign?A. BlueB. YellowC. RedD. Green62. 听力题：The process of combining elements to form compounds is called ______.63. 选择题：What is the name of the famous volcano in Italy?A. Mount FujiB. Mount VesuviusC. Mount St. HelensD. Mount Kilimanjaro答案: B64. 填空题：The ______ of flowers can influence their attractiveness to pollinators. (花的形状可以影响其对授粉者的吸引力。

基于自适应粒子群优化算法的永磁同步电机参数辨识

• 42 •测控技术2018年第37卷第7相先进算法与人工智能基于自适应粒子群优化算法的永磁同歩电机参数辨识袁玉敏(贵州工业职业技术学院机喊与电气工程学院.贵州贵阳550008)摘要：永磁同步电机广泛应用于工业驱动系统中，开展永磁同步电机参數在线辨识对实现电机高性能控制和可靠状态监測具有重要意义。

针对永磁同步电机动态数学模型具有非线性、多参数、强耦合等特点，从电气系统和机械系统两方面建立了永磁同步电机数学模螌，针对参教辨识问题的特点，提出了一个愤性因子的自适应公式.在此基础上，建立了以粒子群算法为框架的自适应粒子稃优化算法，对永磁同步电机定子电阻 < 和负栽转矩7'^进行了在线辨识，并基于实脸乎台验证了辨识结果。

研究结果表明：自适应粒子群优化算法通过不超过20次迭代就可以发现最优参教，模迆参数的估计值和測量值匹肊良好，该算法可在其他类赍电杌的参教辨识中推广应用。

关键词：永磁同步电机;参数辨识；自适应粒子群算法；数学模型；实验验证中图分类号:TM341;TP312 文献标识码:A 文章编号：1000-8829(2018)07 - 0042 - 04d o i：10. 19708/j.ckjs.2018.07.010Parameter Identification of Permanent Magnet Synchronous MotorBased on Adaptive Particle Swarm OptimizationY U A N Y u-m i n(School of Mechanical and Electrical En^pnccring. Guizhou Industry Polytechnic College. Guiyang 550008. China) Abstract: PararmHer idenlificalion with rogartl to a kind of jMrnmincnt magnet synchronous moU>r( P M S M)i s significant for precise control system design. Acquisition of these param e t e r during motor operation is a challenging task d ue to the inherent nonlinearil)- of motor d\Tiamics. A d ynamic model w as conslructed for a kind of P M S M, and a parameler icleiilificalion methcxl with I'egard lo P M S M using adaptive pailiole swarin optimisation(A P S O)w as projx>scd. Simulation results show that the proposed method can effectively identify the P M S M p arameters, which is specifically represented by stator resistance and load toixjue disturbance. At the s a m e lime^ Che meih^kl is generally applioal)!^^ lo other lypfts of moiors.Key words：permanent magnet synchronous motor; parameter identification; adaptive particle s w a r m optimization; mathematical model; experimental verification永磁同步电机（Pcnnancnt M agnt’丨 Synchronous M o» tor, P M S M)具有响应速度快、控制性能好和高功率密度等优点，被广泛川于斯能源发电、混合动力汽个:、精密伺服系统和大型推进系统等T业驱动系统中m。

关于模拟生态系统的英文作文

关于模拟生态系统的英文作文Simulating Ecosystems for Scientific Exploration and Conservation.Ecosystems, intricate webs of interacting organisms and their physical environment, are complex and dynamic systems that underpin the health and stability of our planet. Understanding these intricate systems is crucial for informed decision-making, conservation efforts, and mitigating environmental challenges. However, direct field studies in real ecosystems can be time-consuming, expensive, and often disruptive to the systems themselves. Enter simulation modeling, a powerful tool that allows scientists to create virtual representations of ecosystems, enabling them to explore and experiment in a controlled and cost-effective manner.Simulation models of ecosystems provide a valuable platform for researchers to test hypotheses, predict future scenarios, and evaluate management strategies withoutdirectly impacting real-world systems. By leveraging computational power, scientists can create virtual ecosystems that mimic the complexity and interactions found in nature. These models incorporate data on species distributions, population dynamics, environmental variables, and ecosystem processes to generate realistic representations of the systems being studied.One of the primary applications of ecosystem simulation models is in conservation biology. These models can help identify critical habitats, predict species responses to environmental changes, and evaluate the effectiveness of conservation interventions. For instance, researchers useda simulation model to investigate the impact of habitat fragmentation on bird populations in the Amazon rainforest. By manipulating model parameters and simulating different fragmentation scenarios, they were able to predict that certain species were particularly vulnerable to habitatloss and fragmentation, informing conservation efforts to protect their populations.Ecosystem simulation models also play a crucial role inexploring the impacts of climate change on ecological systems. Scientists can use these models to simulate future climate scenarios and assess their potential effects on species distributions, ecosystem dynamics, and ecosystem services. For example, a study simulating the impact of climate change on coral reefs predicted significant declines in coral cover and species diversity under future warming scenarios, highlighting the urgent need for mitigation and adaptation measures to protect these vital ecosystems.Furthermore, ecosystem simulation models can be used to investigate the effects of human activities on the environment. These models can simulate the impact of land-use changes, pollution, or invasive species on ecosystem structure and function. For instance, a simulation model was used to explore the effects of agricultural expansion on water quality in the Chesapeake Bay. The model predicted that increased fertilizer use would lead to significant increases in nitrogen loads, with potential consequencesfor aquatic ecosystems and human health.While simulation models provide valuable insights into ecosystem dynamics, they also have limitations. Model accuracy and reliability depend heavily on the quality and availability of data, and models may not always capture the full complexity of real-world systems. Additionally, simulations require significant computational resources and technical expertise, limiting their accessibility to some researchers.Despite these limitations, ecosystem simulation models remain an invaluable tool for scientific research and environmental decision-making. By enabling researchers to explore complex systems and test hypotheses in a controlled environment, simulation models provide a powerful means to advance our understanding of ecosystems and inform conservation efforts to protect the health of our planet.。

半经验模型的稳态模拟家用冰箱外文翻译

半经验模型的稳态模拟家用冰箱外文翻译Abstract:Introduction:Refrigerators are essential appliances in households, and their energy consumption accounts for a significant portion of the overall energy usage. Therefore, it is crucial to develop models that can accurately predict their performance and energy consumption, which can aid in designing more energy-efficient refrigerators.Methodology:Results:The simulation is performed to predict the steady-state temperature distribution inside the refrigerator. Various operating conditions, such as ambient temperature, cooling demand, and thermostat setting, are taken into account. The model can accurately predict the temperature distribution and energy consumption of the refrigerator under different operating conditions.Discussion:The semi-empirical model provides a useful tool for understanding the performance of household refrigerators. By accurately predicting the temperature distribution and energyconsumption, it can help in optimizing the design and operation of refrigerators to improve their energy efficiency.Conclusion:The steady-state simulation of a household refrigerator using a semi-empirical model provides valuable insights into its performance and energy consumption. By considering various factors such as thermal properties and heat transfer mechanisms, the model accurately predicts the temperature distribution and energy consumption under different operating conditions. This knowledge can be used to design and operate more energy-efficient refrigerators in the future.。

仿真需求的英语作文

仿真需求的英语作文Title: The Importance of Simulation in Meeting Demands。

In today's dynamic and complex world, the need for simulation has become increasingly vital across various sectors. Simulation serves as a powerful tool to replicate real-world scenarios, allowing for analysis, experimentation, and prediction without the associated risks. This essay delves into the significance ofsimulation in meeting demands across different domains.Firstly, in the realm of engineering and manufacturing, simulation plays a pivotal role in product development and testing. By creating virtual prototypes, engineers can assess the performance, durability, and safety of designs before investing in physical prototypes. This not only accelerates the product development cycle but alsominimizes costs associated with rework and iteration. Moreover, simulation enables engineers to optimize processes, such as manufacturing workflows and supply chainlogistics, leading to enhanced efficiency and productivity.Secondly, in healthcare, simulation is instrumental in training medical professionals and improving patient outcomes. Medical simulations allow practitioners to refine their skills in a risk-free environment, practicing complex procedures and emergency scenarios. From surgical simulations to patient care simulations, healthcare professionals can enhance their decision-making abilities and response times, ultimately saving lives. Additionally, simulation-based research facilitates the development of innovative treatments and medical devices, accelerating progress in the field of medicine.Furthermore, in the realm of urban planning and transportation, simulation aids in designing sustainable and efficient cities. Urban simulations enable planners to model traffic flow, assess environmental impacts, and optimize infrastructure development. By simulating various scenarios, such as population growth or changes in transportation systems, urban planners can make informed decisions to alleviate congestion, reduce pollution, andenhance overall livability. Simulation also plays a crucial role in disaster preparedness and response, allowing authorities to simulate emergency scenarios and develop effective evacuation plans.In finance and economics, simulation serves as a valuable tool for risk management and decision-making. Financial simulations enable analysts to model market behavior, assess investment strategies, and stress-test financial systems. By simulating different economic scenarios, policymakers can evaluate the potential impactof policy interventions and make informed decisions to mitigate risks and foster economic stability. Moreover, simulation-based forecasting provides insights into future trends, helping businesses and governments adapt tochanging market conditions.In conclusion, simulation is indispensable in meeting the demands of today's complex and interconnected world. Whether in engineering, healthcare, urban planning, finance, or other domains, simulation enables analysis, experimentation, and prediction in a controlled environment.By harnessing the power of simulation, stakeholders can make informed decisions, optimize processes, and mitigate risks, ultimately driving progress and innovation across various sectors. As technology continues to advance, the role of simulation will only grow in importance, shaping the future of industries and societies alike.。

自证预言是一种心理学现象作文

自证预言是一种心理学现象作文英文回答：Self-fulfilling prophecy is a psychological phenomenon in which a person's beliefs about a situation or an event lead them to act in a way that makes the belief come true. This can be a positive or negative effect, depending on the belief.For example, if a person believes that they are going to fail a test, they may become anxious and nervous when taking the test, which can lead to them actually failing the test. Conversely, if a person believes that they are going to succeed on a test, they may become more confident and focused when taking the test, which can lead to them actually succeeding on the test.Self-fulfilling prophecies can be created through both positive and negative thoughts and expectations. For example, if a person believes that they are going to have agood day, they may behave in a more positive and optimistic way, which can lead to them actually having a good day. Conversely, if a person believes that they are going to have a bad day, they may behave in a more negative and pessimistic way, which can lead to them actually having a bad day.Self-fulfilling prophecies can be a powerful force in our lives, but we can learn to control them by becoming aware of our thoughts and expectations. By challenging our negative beliefs and focusing on our positive beliefs, we can create a more positive and fulfilling life.中文回答：自我实现预言是一种心理学现象，在这种现象中，一个人对某一情况或事件的信念会导致他以一种使信念成真的方式行动。

Oscillator

The Design of 2.4GHz Bipolar Oscillator by Using theMethod of Negative ResistanceCheng Sin Hang TonySept.14,2001IntroductionIn this application note,the design on a 2.4GHz bipolar oscillator by the method of negative resistance will be used.In the design,a circuit simulator Advanced Design System (ADS)from Agilent Technologies will be used and it will be used to evaluate the performance of the designed oscillator at the end of the design.TheoryIn the negative resistance oscillator design,the negative resistors can be realized easily by a three terminals active device with proper feedback.This negative resistor is used to cancel out the lost from the resonator.The figure above (Fig.1)shows a typical negative resistance oscillator.First,it is necessary to make sure the overall circuit to be unstable such that:0<+L IN R R (1)When a stable oscillation occurs,the following conditions must be satisfied:0=+L IN R R ..............(2)0=+L IN X X . (3)Base on the theory above,a negative resistance will be designed and simulated in ADS to satisfy equation (1)and a resonator will be designed and simulated in ADS to satisfy equation (2)and (3).Finally,the combined circuit will be simulated in ADS by the method of harmonic balance to see the overall performance the oscillator.SimulatorThere are many different simulators provided in ADS.In this oscillator design,only some are needed and they will be introduced here.a.DC simulatorThe DC simulator (Fig.2)is used to simulate the dc performance of the circuit.It is used to design the dc biasing circuit in this design.Fig.1Negative resistance oscillatorFig.2DC simulatorADS Application NotesMicrowave Laboratory,Department of Electronic Engineering The Chinese University of Hong Kongb.S-parameter (S_param)simulatorThe S_param simulator is used to find the circuit parameters such as s-,z-and y-parameters.The start and stop frequency of the wanted parameter is required by the simulator (Fig.3).Besides,a circuit termination should be added in the circuit schematic as the measurement port of the circuit.It is used to find the input impedance of the active device in the negative resistance design and used to check the three oscillation condition equations in the resonator design.c.Harmonic balance (HB)simulatorThe HB simulator is used to simulate the performance of the oscillator.In this simulator,the expected fundamental frequency is required.Besides,an osc-port component is added in the circuit schematic.The osc-port should be placed such that it separates the negative-resistance portion of the oscillator from the resonator portion.The arrow should point in the direction of the negative resistance.This simulator is used in the final evaluation of the oscillation circuit.Circuit Simulation and Resulta.Biasing circuitBefore we start the design,a suitable transistor should be selected and provided a suitable dc bias (Fig.6).In this design,the Agilent Technologies High Performance Isolated Collector Silicon Bipolar Transistor HBFP0450will be used.It will be biased to operate at 2V V CE and 20mA I C .The model of the transistor used in the simulation can be found in ADS component library (Fig.5).In this simulation,the DC simulator in ADS is used to make sure the required biasing condition isobtained.Fig.3S_paramsimulatorFig.4Harmonic balancesimulatorFig.5Transistor HBFP0450model in ADSb.Negative resistanceAfter designed the biasing circuit,the transistor will be constructed as a common emitter capacitive feedback circuit (Fig.7).This will produce a negative resistance in order to cancel the lost from the resonator.In this simulation,the S_param simulator in ADS is used to get the input impedance of the circuit.From the simulation result,it shows that the overall resistance of the circuit is zero near 2.4GHz (Fig.8)and it satisfies equation (2).The reactance of the active device is capacitive at this frequency.It means that an inductiveresonant tank is needed inthis frequency to achieve the 2.4GHz oscillatordesign.Fig.6Biasingcircuit Fig.7Negative resistance and resonator simulation circuitc.ResonatorNow,an inductive resonator is needed in order to make the circuit oscillate.In the resonator,a 4pF capacitor is used to increase the oscillation frequency of the circuit due to the limited value of the lumped inductor.It acts as a dc-block of the resonator also (Fig.7).The Q-factor of the inductor is assumed to be 36.It will give a lost in the form of a resistor of 0.8378Ω.It is included in the simulation in order to give a more accurate simulation result.The circuit is simulated by the S_param in ADS again.From the simulation result,it shows that the net reactance equals to zero near 2.4GHz (Fig.8).This satisfies equation (3).d.Full simulation and circuit evaluationBy combining the negative resistance and the resonator,the performance of the oscillator can be evaluated now.By modifying the circuit in Fig.7,an oscillator circuit is obtained (Fig.9).Here,the HB simulator is used.This simulator can simulate the fundamental frequency,output power and phase noise performance of the oscillator.Besides,the DC simulator will be used again to have a whole evaluation of the circuit.After the simulation,the performance of the oscillator can be obtained (Fig.10).The circuit oscillates at 2.4223GHz giving 4.575dBm output power.The circuit phase noise at 100kHz and 1MHz offset are -100.268dBc/Hz and -120.268dBc/Hz respectively.The dc simulation shows the required biasing condition also.Fig.8Negative resistance and resonator simulation resultIN )Re(Z L )Re(Z IN )+Re(Z L )Im(Z IN )Im(Z IN )+Im(Z L )Im(Z L )ConclusionIn this application note,a typical negative resistance oscillator designed by using the advanced circuit simulator ADS is presented.By using a powerful simulator,the design time can be greatly reduced and engineers can have a good expectation on the circuit performance before the implementation of thecircuit.Fig.9 2.4GHz oscillatorcircuitFig.10Oscillator performance。

天津市天津市和平区2023-2024学年高二上学期1月期末英语试题

天津市天津市和平区2023-2024学年高二上学期1月期末英语试题学校:___________姓名：___________班级：___________考号：___________一、单项选择1．As schools struggle to survive on smaller budgets, the ongoing debate over whether physical education classes should be cut will certainly be ________.A．fed B．fueled C．hit D．illustrated 2．—I have been working hard at my English in the past two months, but I think I make little progress in it.________ , Emma! Your English will soon be perfect.A．I can’t help it B．Make itC．Hang in there D．You really have me there3．________her illness leaving her very weak at times, she tries to gain pleasure from life A．Despite B．However C．Although D．Instead of 4．Consumers think highly of this auto company, ________expense the problem cars under guarantee are repaired.A．at which B．at whose C．for which D．for whose 5．In China, a man from Jiangsu Province ________ from university at the age of 88,________him the oldest university graduate in the country.A．graduated; making B．graduated; to makeC．being graduated; made D．having graduated; made6．We ________the evening until Frank________to an emergency.A．enjoyed; had been called B．enjoyed; was callingC．were enjoying; was called D．had enjoyed; has called7．________the very high rents charged, some parents consider buying as a(n)________ A．Faced; solution B．Facing; chanceC．Facing with; option D．Faced with; alternative8．Listen! The coach ________the strengths of our opponents because ourteam________against them before.A．has explained; weren’t playing B．explains; won’t playC．is explaining; haven’t played D．will explain; hadn’t been playing9．________the tourists didn’t want to go to the town where the earthquake had taken place just a few weeks before.A．Reluctantly B．ApproximatelyC．Extremely D．Understandably10．The doctor ordered the woman to be________all solid food for at least twenty four hours.A．kept out B．kept away C．kept off D．kept up二、完形填空I was living in Cali, Colombia. One day my younger sister decided to visit me for asuccess. If you are prepared to bounce back when everyone else 29 , you will be the winner. Think of your contingency plan as a form of 30 , one that, if nothing else, can give you the peace of mind you need.11．A．heart B．sight C．track D．touch 12．A．heading B．leaving C．driving D．going 13．A．better B．easier C．funnier D．worse 14．A．picked up B．checked up C．ended up D．came up 15．A．down B．off C．by D．out 16．A．choice B．evidence C．hope D．reason 17．A．arrive B．pass C．reach D．return 18．A．station B．direction C．location D．position 19．A．in time B．on time C．behind time D．ahead of time 20．A．allowed B．reminded C．forced D．begged 21．A．agreed B．appeared C．succeeded D．signed 22．A．advice B．control C．responsibility D．risk 23．A．coming into effect B．getting into trouble C．putting into practice D．taking into account24．A．approves of B．looks up C．goes after D．turn to 25．A．accessed B．altered C．approached D．avoided 26．A．dangerous B．essential C．pointless D．priceless 27．A．extremer B．faster C．better D．stranger 28．A．capability B．flexibility C．reliability D．stability 29．A．breaks down B．settles down C．gets over D．carries away 30．A．assistance B．endurance C．guidance D．insurance三、阅读理解Are you looking for a fun day out in New York at a reasonable price? Then look no further than the amusement parks situated at. the historic Coney Island entertainment center in New York City, offering something for the whole family to enjoy here, including games, rides and restaurants. For non-stop entertainment, Coney Island is the place to be!31．What do we know about the Astroland’s POP ticket?A．Though expensive, it is more convenient.B．It can be used for the whole year around.C．It can be repeatedly used for many times.D．It can be used for public transport as well.32．Which Park would a family with younger children probably choose to visit?A．Water Flume slide in Haunted HouseB．Astroland Amusement ParkC．Coney Island BoardwalkD．Deno’s Wonder Wheel Park33．Which of the following is the passage probably taken from?A．A tour brochure.B．A safety regulations.C．A travel journal.D．A traffic guide.Packing up her bedroom in Virgin a Beach, Douglas had to say goodbye to her family, to her two dogs, and to the beach, where she loved to ride waves on her boogie board. But it was time to take the leap, however, heartbreaking and awkward it would be. Even at 14, Douglas knew that.So off she went about 1.200 miles to West Des Moines, Iowa, to train with a coach from China and live with a white family she had never been met. When she arrived,\Douglas thought that she must be the only black person in the state.“I was unpacking and saying, ‘What am I doing?’”said Douglas, who is 16.“it was like:’Where do I put everything? Where are the spoons?’ I’d wake up and say, ‘This is my bed,where am I?’”Liang Chow, who had coached the Olympic gold medalist Shawn Johnson, transformed Douglas into one of the best gymnasts in the world, helping her skyrocket from an average member of the national team to the top of the sport. And a couple with four young daughters became her second family, nurturing her in low a while her real family|supported her from afar,(遥远地).That move also was important in Douglas’s making history. By winning the Olympic all-round title, she became the first black woman to do so. She also became the fourth American woman to win the all-round, following Mary Lou Rettonjin 1984, Carly Patternson in 2004 and Nastia Liukin in 2008.Douglas won, scoring 62.232 points, and led the competition from beginning to end.’Viktoria Komova, who sobbed into her coach’s chest when she learned she had lost, won the silver, with 61.973 points. Aliya Mustafina. the 2010 world all-round champion, won the bronze with 59.566 points. The other American in the competition, Aly Raisman finished fourth after losing a tiebreaker(决胜局) to Mustafina.Douglas said she had felt confident all along that she would win.“It was just an amazing feeling,”she said,“I was just like, believe, don’t fear, believe.”34．Douglas left her home at 14 because sheA．didn’t like her dogsB．needed training to make a differenceC．wanted to live with her second familyD．wanted to become the only black champion in the stateA．uneasy B．excitedC．independent D．tired36．What can we learn about the competition mention ed in the passage?A．Komova felt stressed during the game and lost her heart.B．Douglas stayed ahead throughout the whole game.C．Aliya came from America and won the third place.D．Most of the competitors were from America.37．Which of the following statements about|Douglas is TRUE?A．She was the first American woman to win the all-around.B．She was the only black person in the state of Iowa.C．Her family didn’t like the idea of her becoming a gymnast.D．Her move to Iowa brought her the chance to succeed.You sitting in the classroom waiting for the teacher to pass out the tests, the door opened and a man walked in, but he wasn’t the regular teacher. You tried to say that you were in the wrong place, but couldn’t open the mouth. You kept trying but it was useless. Finally, you yelled, “Wait!”. Then you opened the eyes and realized it was only a crazy dream.What happens to our minds and bodies when we’re asleep? To find out, scientists have set up “sleep laboratories.”, where scientists use machines to keep track of people’s heartbeats, watch their muscular (肌肉的) movements and their brainwaves are recorded too.Scientists believe that people go through five stages of sleep. All five stages are repeated four to six times each night. Stage one is a very light sleep. But stage four is the deepest sleep of all. If you’re very tired, you will spend a lot of time in stage four. Then you pass into the fifth state. Your heart starts beating faster. Your eyes move back and forth very quickly under closed lids. You are dreaming.The fifth stage is called REM sleep, which stands for Rapid Eye Movement. How do scientists know all this? They work with sleep volunteers. If you were a sleep volunteer, this is what scientists would do. Every time you went into REM sleep, they would wake you up. After a few nights, you might start going into REM sleep sooner and more often than usual. The scientists would be kept very busy trying to wake you up. They might think you were trying hard to make up for the lost dream time!What this may mean is that people need to dream just as they need to sleep. When you’ve been asleep, your mind doesn’t turn off. It keeps on thinking. And your sleeping mind tums your thoughts into a technicolor movie with sound, lights, and a huge cast. Sometimes you may dream you are being chased by something you can’t see. Sometimes you may fall without getting hurt. And in some dreams, your best friend turns into a monster, or your cat talksDreams can be scary, funny, or just plain boring. But what do they mean? In ancient times, people said dreams told them about the future. Today most experts think that dreams teach people about themselves. You may not understand all your dreams, but at least you can enjoy them. In your dreams, you can discover a whole other world!38．What is the purpose of setting up sleep laboratories?A．To watch and take care of people while they are asleep.B．To find out what happens to our minds and bodies when we are asleep.C．To find out the five stages of sleep.D．To find out what’s REM sleep.39．From Paragraph 3 we know thatA．the same dream may repeat all the timeB．people dream only when they are tiredC．everyone dreams at nightD．when you dream you are in the deepest sleep40．According to the passage, why are scientists busy waking up volunteers during the test?A．To disrupt their sleep patterns.B．To monitor the occurrence of dreaming.C．To ensure they sleep well enough.D．To observe their muscular movements.41．What can be inferred from the last paragraph of the passage?A．Dreams can be mysterious and unpredictable.B．Dream analysis has been consistent throughout history.C．Experts believe dreams provide self-insight.D．People enjoy dreams even if they don’t understand them.Positive psychology is a relatively new sub-field of psychology that focuses on human strengths and the things that make life worth living ——to move beyond surviving to flourishing (昌盛, 茂盛). Theorists and researchers in the field have sought to identify the elements of a good life. They have also proposed and tested practices for improving life satisfaction and well-being. While psychologists have studied topics like happiness, optimism,and other human strengths for decades, positive psychology wasn’t officially identified as a branch of psychology until 1998 when Martin Seligman was elected president of the American Psychological Association (APA). Seligman called for research into what makes normal people’s lives positive and fulfilling. He stated that psychology should be just as concerned with nurturing the good things in life as it was with healing the bad. From these ideas positive psychology was born.Today, positive psychology is sometimes confused with self-help movements. However, positive psychology is a science.Positive psychologists don’t wish to discard the study of human problems. They simply wish to add the study of what’s good in life to the field.Despite its ongoing popularity, positive psychology has been criticized for a number of different reasons. First, humanistic (人本主义的) psychologists have argued that Seligman is claiming credit for the work previously done in humanistic psychology. Also, some have said that the research produced by the sub-field is invalid or overstated. Similarly, some claim that positive psychology fails to take individual differences into account. Instead presenting findings as it they will work for everyone in the same way.Finally, some have suggested that positive psychology is limited by cultural bias (偏见). Positive psychology’s findings often come from a middle-class perspective that ignores. issues such as systemic inequality and poverty. Recently, however, attempts have been made to expand the findings in positive psychology to incorporate (合并) perspectives from non-Western countries and a diversity of backgrounds.42．What can we learn about the Positive psychology from the first paragraph?A．Positive psychology is finding a new way for humans to survive.B．Psychologists have already studied positive psychology for decades.C．It was in 1998 that positive psychology became a branch of psychology study.D．Positive psychology focuses on both human strengths and problems.43．What. does the underlined word “discard” in Paragraph 3 mean?A．Abandon.B．Explore.C．Divide.D．Evaluate.44．How is the future development of positive psychology according to the last paragraph?A．Steady.B．Promising.C．Uncertain.D．Fruitless.45．What is the best title of the passage?A．Positive psychology—make life worth/living.B．Psychology development and culture diversity.C．Seligman and his lifelong study.D．Psychology study and daily life.阅读短文，按照题目要求用英语回答问题。

The Psychology of Procrastination

The Psychology of Procrastination Procrastination is a common phenomenon that affects people from all walks of life. It is the act of delaying or postponing tasks, often to the point of causing stress and anxiety. The psychology of procrastination is a complex andmultifaceted issue that has been studied extensively by psychologists and researchers. In this essay, we will explore the various factors that contribute to procrastination, the impact it has on individuals, and potential strategies for overcoming it. One of the primary factors that contribute to procrastination is the concept of time inconsistency. This refers to the tendency for people to value immediate rewards more highly than future rewards. In other words, individuals may prioritize short-term pleasure or relief from discomfort over long-term goals or responsibilities. This can lead to a cycle of procrastination, as individuals continually put off important tasks in favor of more immediately gratifying activities. Another contributing factor to procrastination is fear of failure. Many people procrastinate because they are afraid of not meeting their own or others' expectations. This fear can be paralyzing and lead individuals to avoid tasks that they perceive as challenging or daunting. In some cases, individuals may even self-sabotage by procrastinating, as a way of protecting themselves from the potential pain of failure. Additionally, perfectionism is a common trait among procrastinators. Perfectionists may put off tasks because they are afraid of not being able to complete them to their own high standards. This fear of making mistakes or falling short of their own expectations can lead to procrastination,as individuals may feel overwhelmed by the pressure to perform perfectly. Furthermore, procrastination can also be a result of poor time management skills. Some individuals may struggle to prioritize tasks effectively, leading to a sense of being overwhelmed by the sheer volume of responsibilities. This can result in a cycle of procrastination, as individuals may feel unable to tackle their to-dolist and therefore put off tasks until the last minute. The impact of procrastination on individuals can be significant. It can lead to increased stress, anxiety, and feelings of guilt or shame. Procrastinators may also experience a decline in their overall well-being, as the constant cycle of putting off taskscan lead to a sense of unfulfillment and dissatisfaction. In addition,procrastination can have negative effects on relationships and work performance, as individuals may struggle to meet deadlines or fulfill their obligations. Despite the negative impact of procrastination, there are strategies that individuals can use to overcome it. One approach is to break tasks down into smaller, more manageable steps. This can help to reduce feelings of overwhelm and make it easier to get started on a task. Additionally, setting specific and achievable goals can help individuals to stay focused and motivated. Another strategy for overcoming procrastination is to address underlying fears or insecurities. This may involve challenging negative thought patterns and developing a more positive and realistic mindset. Seeking support from friends, family, or a mental health professional can also be beneficial in addressing the emotional aspects of procrastination. Furthermore, developing strong time management skills can help individuals to better prioritize tasks and allocate their time effectively. This may involve using tools such as to-do lists, calendars, or time-blocking techniques to stay organized and on track. Additionally, learning to recognize and challenge perfectionist tendencies can help individuals to let go of unrealistic expectations and reduce the pressure they place on themselves. In conclusion, the psychology of procrastination is a complex issue that is influenced by a variety of factors, including time inconsistency, fear of failure, perfectionism, and poor time management skills. Procrastination can have significant negative effects on individuals, leading to increased stress, anxiety, and a decline in overall well-being. However, there are strategies that individuals can use to overcome procrastination, such as breaking tasks down into smaller steps, addressing underlying fears and insecurities, and developing strong time management skills. By understanding the psychology of procrastination and implementing effective strategies, individuals can work towards overcoming this common and challenging issue.。

北京2024高考英语试卷

What is the main idea of the passage?A. The history of space exploration.B. The challenges faced by astronauts in space.C. The benefits of space research for humanity.D. The future plans for space colonization.Which of the following words best describes the author's tone in the text?A. Sarcastic.B. Objective.C. Emotional.D. Biased.The word "it" in the second paragraph refers to:A. the new technology.B. the environmental issue.C. the previous study.D. the government policy.According to the passage, which of the following is NOT a reason for the decline in wildlife populations?A. Habitat loss.B. Climate change.C. Overhunting.D. Increased conservation efforts.What does the author suggest as a solution to the problem discussed in the text?A. More strict laws.B. Public awareness campaigns.C. Technological advancements.D. International cooperation.The passage argues that the most effective way to improve education is through:A. Increased funding.B. Teacher training.C. Smaller class sizes.D. Longer school days.Which of the following statements is supported by the information in the passage?A. All animals are equally affected by pollution.B. Some species are more resilient to environmental changes than others.C. Pollution has no long-term effects on ecosystems.D. The impact of pollution can be reversed quickly.The author's primary purpose in writing the passage is to:A. Entertain readers.B. Inform and educate.C. Promote a product.D. Persuade readers to take action.What is the passage primarily about?A. The history of art.B. The importance of creativity in society.C. Different types of artists.D. The influence of technology on art.。

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a rX iv:physics /0512128v1[physics.s pace-ph]14Dec25GEOPHYSICAL RESEARCH LETTERS,VOL.,XXXX,DOI:10.1029/,Simulation Study of a Positive Ionospheric Storm Phase Observed at Millstone Hill M.Swisdak,1J.D.Huba,2G.Joyce 1,and Chao-Song Huang 3X-2SWISDAK ET AL.:POSITIVE STORM SIMULATIONS Abstract.Simulation results from the NRL ionospheric model SAMI2indicate that the changes in the F-region over Millstone Hill during the geomagnetic storm beginning on3April2004are primarily due to the inﬂuence of a long-lasting eastward electricﬁeld,as was previously suggested by Huang et al.[2005].A simulation of the storm day agrees well with the observational data and shows that,compared with the ionosphere of the previous quiet day,the peak electron density in the F-region(N m F2)increased by a factor of≈2,the altitude of the peak density(h m F2)rose by≈80km,and the F-region elec-tron temperature decreased by≈1000K.Further simulations in which ei-ther the neutral atmosphere and winds or the electricﬁeld were replaced by their quiet day counterparts clearly suggest that the electricﬁeld played the dominant,although not exclusive,role in producing these eﬀects.SWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-3 1.IntroductionAfter an extended quiet period lasting from29March to2April2004a magnetic storm began at1412UT on3April and reached a minimum Dst of-149nT at0042UT on the following day.Huang et al.[2005]reported that this event triggered large,long-lasting changes in the daytime ionosphere,including a strong positive ionospheric storm phase(i.e.,a period in which the F-region electron density increased).Understanding long-duration mid-latitude positive storms such as this is of particular interest because they have signiﬁcant eﬀects on large regions of the ionosphere.Buonsanto[1999]noted that the generation of such events is one of the main unresolved problems in ionospheric research.Two mechanisms have been proposed as drivers of such dayside storms:winds in the neutral atmosphere and electricﬁelds(see Figure1).In the former,heat inputs in the auroral regions are thought to cause global changes in the wind circulation pattern and thermospheric composition[Rishbeth et al.,1985;Fuller-Rowell et al.,1994],including the generation of equatorward neutral winds that lift the mid-latitude F-region[Jakowski et al.,1990;Bauske and Pr¨o lls,1997;Lu et al.,2001].(In Figure1,V n·B<0and the collisionally-coupled plasma is driven up theﬁeld lines.)On the other hand,Foster and Rich[1998]reported direct observations of the uplift of the mid-latitude ionosphere by a prompt penetration eastward electricﬁeld(in Figure1the E×B drift is upward and poleward).These processes are not completely distinct since,for example,equatorward neutral winds can maintain a dynamo electricﬁeld.X-4SWISDAK ET AL.:POSITIVE STORM SIMULATIONSHuang et al.[2005]suggested that the proximate cause for the3April storm was an enhanced eastward electricﬁeld that lifted the mid-latitude ionosphere for several hours. In this Letter we present simulations that support this conclusion,although the neutral winds do seem to play a minor,but important,role.We describe our computational model SAMI2in section2,present the simulation results in section3,and discuss our conclusions in section4.putational ModelSAMI2is a two-dimensional,semi-implicit,Eulerianﬂuid model of the low to mid-latitude ionosphere at one geomagnetic longitude[Huba et al.,2000].Previous studies have shown that SAMI2simulations of the F-region electron density are in good agreement with data from both satellites[Huba et al.,2002]and the Millstone Hill observatory[Huba et al.,2003].In this study the simulation domain passes through a point330km above Millstone Hill(42.6◦N,288.5◦E,invariant latitude55◦)and has north-south extrema at geographic latitudes of−68.7◦and45.2◦.We place201gridpoints along each of114ﬁeld lines with non-uniform spacing in both dimensions to achieve better resolution at low altitudes.Test runs in which the number of points in either dimension is doubled suggest our results have converged.Theﬁrst and last gridpoints of eachﬁeld line are at an altitude of85km and the apexes range between150and14,000km(L values of1.02to3.20).We model the terrestrial magneticﬁeld as an oﬀset,tilted dipole for which the center as well as the geographic latitude and longitude of the magnetic north pole have been chosen to maximize agreement in the simulation domain with the International GeomagneticSWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-5 Reference Field.Parallel to theﬁeld,i.e.,along aﬂux tube,we solve theﬂuid continuity and momentum equations for seven ion species(H+,He+,N+,O+,N+2,NO+,and O+2)and the temperature equation for three(H+,He+,and O+).The temperatures of the other four ions are taken to be equal to that of O+.To model the electrons we assume that the charge density and parallel current density vanish,which then determines the electron density and velocity parallel to theﬁeld;the electron temperature equation is solved separately.The empirical models NRLMSISE-00and HWM93[Picone et al.,2002;Hedin et al.,1991]specify the composition and winds of the neutral atmosphere,respectively. We assume that transport perpendicular to the magneticﬁeld is solely due to E×B drifts.Toﬁnd the electricﬁeld throughout the simulation domain we extrapolate from measurements of the east-west(E x)and north-south(E y)components of the electricﬁeld in the F-region above Millstone Hill by making two assumptions.Theﬁrst,that every (dipolar)ﬁeld line is an equipotential,allows us to calculate the E×B drift everywhere on aﬁeld line once we know it anywhere on aﬁeld line.The second,that the(vertical) drift varies as L2at the magnetic equator,is valid when the electricﬁeld is curl-free and the azimuthal neutral wind dynamo is negligible[Eccles,1998].Given a drift at Millstone Hill of magnitude v M the magnitude of the drift at any other point in the simulation domain isv E×B=v M 1+3cos2θ sinθL M 2,(1) whereθis the magnetic co-latitude.The direction of the drift is always perpendicular to B and hence varies along aﬁeld line.X-6SWISDAK ET AL.:POSITIVE STORM SIMULATIONSThe incoherent scatter radar at Millstone Hill measures three-dimensional ion velocities (from which the electricﬁeld can be determined)and meridional neutral winds with a time resolution of≈30minutes.Typical errors are±0.2mV/m for the electricﬁeld and ±20m/s for the wind.Huang et al.[2005]give a more complete description of the mea-surements.The two relevant components of the electricﬁeld as well as the corresponding E×B drifts are plotted in the top two panels of Figure2.Because of the non-zero magnetic declination at Millstone Hill(≈−15◦)both the east-west and north-south com-ponents contribute to the drift,although the north-south contribution is minimal until ≈20UT on3April.At Millstone Hill a3mV/m east-west electricﬁeld implies a total drift speed of≈60m/s and a vertically projected drift speed of≈20m/s. Unfortunately,although we have measurements of the average F-region meridional neu-tral wind above Millstone Hill,there is no straightforward way to extrapolate this data to the entire simulation domain.Moreover,we have no measurements of the zonal winds.We instead use the velocities(both meridional and zonal)from the empirical model HWM93. The model values for the meridional wind are plotted in the bottom panel of Figure2 along with the observations.While the basic features of the data sets agree there are some notable diﬀerences,particularly in the magnitude of the wind during the early evening and pre-dawn hours(local time at Millstone Hill=UT-5).Possible eﬀects of these dis-crepancies are discussed further in Section4.Note that because of the large dip angle at Millstone Hill only1/3of the meridional wind speed is projected along the magneticﬁeld. SAMI2’s empirical models of the neutrals and solarﬂux depend on the geophysical parameters F10.7,F10.7A and Ap—the previous day’s solarﬂux at10.7cm,the81-daySWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-7 centered average of F10.7,and the Ap index.For both days F10.7A=105.1;on2April F10.7=114.1and on3April F10.7=108.6.The daily Ap=3on2April and41on3 April,but we also usedﬁner gradations(e.g.,3-hour ap indices)in NRLMSISE-00and HWM93.3.Simulation ResultsIn Figure3we compare our simulation results to the observed electron densities and temperatures at an altitude of330km above Millstone Hill.The overall agreement is good,with the simulation successfully modeling the major changes between the quiet and active days.After the storm begins(≈14UT on3April)the electron density quickly increases,peaking at≈1.4×106cm−3,or roughly2−3times the density at the same time on the previous day.Simultaneously the electron temperature drops by≈1000K. However several discrepancies can be seen.Theﬁrst is in the electron temperature on 2April when the model overshoots the observed value by roughly10%at12UT and remains too high for several hours.This is probably due to the photoelectron heating model used in SAMI2and is discussed further in Section4.A second discrepancy is the ∼1hour lag between the onset of the simulated and actual storm on3April.Winds can cause such a delay by retarding theﬂow of material up aﬁeld line,but both the modeled and true meridional winds are relatively modest at this time.However HWM93predicts a relatively large zonal wind(≃100m/s)during this period which,when projected onto the magneticﬁeld,is large enough to cause the delay.An otherwise identical simulation that was performed with no zonal winds exhibited no lag in the storm onset.X-8SWISDAK ET AL.:POSITIVE STORM SIMULATIONSTo better show the eﬀects of the storm on the F-region as a whole we plot N m F2and h m F2at Millstone Hill for both the observations and the simulation in Figure4.h m F2 remained below300km during daylight hours on2April but during the storm on the following day it rose by50−80km.Viewed from aﬁxed altitude of330km the rise of the F-region leads to an increase in the local electron density and a decrease in the electron temperature(see the top panel of Figure3),i.e.,cooler,denser plasma moves to higher altitudes.Note that this mechanism does not depend on what process lifts the F-region. To test the relative importance of the electricﬁeld and the neutral atmosphere and winds in driving these large changes we performed two further simulations of the storm day.In theﬁrst we replaced the models of the neutral atmosphere and winds with their quiet day counterparts;in the second we used the storm day neutral atmosphere and winds and the quiet day electricﬁeld.The results are shown in Figure5.For the storm day electricﬁeld and the quiet day neutrals(dotted black line)the largest change from the original simulation is the∼2hour delay in the ionosphere’s response to the storm’s onset.We attribute this to the neutral wind.The quiet day neutral wind is poleward which,as noted earlier,pushes plasma down theﬁeld line and suppresses, albeit not completely,the increase in electron density after14UT.There are also some minor diﬀerences in the temporal evolution of the electron density,particularly late in the storm(20−22UT)when the simulation density rises as the observed density falls. In comparison the simulation with the quietﬁeld and storm neutrals correctly captures the onset of the storm but diverges from the observations after16UT.In particular,this simulation underestimates the peak density by≃50%.We attribute this to the quietSWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-9 day electricﬁeld that changes from eastward to westward at≃18UT,thus pushing the F layer downward and reducing the electron density.Together these simulations suggest that the neutrals played a role in the initial stages of the storm but the electricﬁeld was the principal driver of the ionospheric evolution.4.DiscussionWe have presented a simulation study of storm-time eﬀects on the mid-latitude iono-sphere over Millstone Hill observatory using the NRL ionosphere code SAMI2.The simu-lation results agree reasonably well with the observations on both the quiet and the storm days.In particular,the model predicts the changes in the ionosphere over Millstone Hill relative to the previous(quiet)day:the F-peak altitude rose by≈80km,the F-peak elec-tron density increased by a factor of≈2,and the F-region electron temperature decreased by≈1000K.We primarily attribute these dramatic changes to the long-lasting eastward electricﬁeld observed on the storm day between12–20UT that lifts cold,dense plasma to higher altitudes.We base this conclusion in large part on Figure5,which indicates that the storm day neutral wind and quiet day electricﬁeld do not suﬃciently account for the observations.By contrast,the active day electricﬁeld and quiet day neutral wind do capture the salient eﬀects of the storm:a large enhancement in the electron density and decrease in the electron temperature.The variations of the electron density and temperature with altitude were also measured around19UT on both the quiet and active days.Not surprisingly,in light of the data shown in Figure4,Huang et al.[2005]found that the storm day had higher electron densi-X-10SWISDAK ET AL.:POSITIVE STORM SIMULATIONSties,lower electron temperatures,and higher h m F2s.Although the simulation agrees with these trends there are discrepancies,particularly in the temperature,at higher altitudes. These diﬀerences may be due to SAMI2’s treatment of photoelectron heating.Collisions are suﬃciently frequent at low altitudes(below roughly250km,although there is some variation with the neutral density)that we assume photoelectrons deposit their energy locally.Above that point our model expresses the(non-local)heating as a function of the integral of the electron density along aﬁeld line.More sophisticated,but computationally intensive,approaches discretize the electron distribution function in energy space and solve some form of a Boltzmann transport equation.The transition between local and non-local heating is continuous in SAMI2,but during non-equilibrium periods unphysical short-lived temperature plateaus occasionally develop around450km.By making ad hoc adjustments to the details of our model we have established that these features have only minimal eﬀects on the plasma at lower altitudes.A thorough study of the origin of the prolonged,storm-time eastward electricﬁeld would require a coupled ionosphere-magnetosphere model that is beyond the scope of this Letter.However two possible sources are(1)a penetration electricﬁeld associated with a rapid change in the inner magnetospheric electricﬁeld at storm onset(e.g.,Kikuchi and Araki[1979],Foster and Rich[1998])and(2)a wind driven dynamoﬁeld associated with high-latitude heating of the atmosphere and the generation of equatorward neutral winds (e.g.,Fuller-Rowell et al.[1994]).Huang et al.[2005]argued for a penetration electric ﬁeld because it can quickly propagate to low latitudes,in agreement with the minimal lag between the storm onset and the ionospheric response seen in the data.Furthermore,SWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-11 no strong equatorward winds were observed at Millstone Hill during the storm.(see the bottom panel of Figure2).A better comparison between simulations and data could be made with more realistic values for the neutral winds throughout the E and F regions.These can be obtained through either more detailed observations or a coupled thermosphere-ionosphere model. In the short term we will pursue the former approach using,for example,measurements taken at Millstone Hill for the September2005ISR World Month campaign(L.P.Gon-charenko,private communication).Finally,we will also use SAMI3,an extension of SAMI2to all longitudes,to investigate longitudinal eﬀects such as the possible generation of inhomogeneous total electron content(TEC)enhancements by a poleward electricﬁeld (Vlasov et al.[2003]).Acknowledgments.This work was supported by the Oﬃce of Naval Research.Work at MIT Haystack Observatory was supported by an NSF cooperative agreement with the Massachusetts Institute of Technology.ReferencesBauske,R.,and G.W.Pr¨o lls,Modeling the ionospheric response to traveling atmospheric disturbances,J.Geophys.Res.,102,14,555,1997.Buonsanto,M.J.,Ionospheric storms—a review,Space Sci.Rev.,88,563,1999. Eccles,J.V.,A simple model of low-latitude electricﬁelds,Geophys.Res.Lett.,103, 26,699–26,708,1998.X-12SWISDAK ET AL.:POSITIVE STORM SIMULATIONSFoster,J.C.,and F.J.Rich,Prompt midlatitude electricﬁeld eﬀects during severe geo-magnetic storms,J.Geophys.Res.,103,26,367,1998.Fuller-Rowell,T.J.,M.V.Codrescu,R.J.Moﬀett,and S.Quegan,Response of the thermosphere and ionosphere to geomagnetic storms,J.Geophys.Res.,99,3893,1994. Hedin,A.E.,et al.,Revised global model of the thermosphere winds using satellite and ground-based observations,J.Geophys.Res.,96,7657,1991.Huang,C.-S.,J.C.Foster,L.P.Goncharenko,P.J.Erikson,W.Rideout,and A.J. Coster,A strong positive phase of ionospheric storms observed by the Millstone Hill incoherent scatter radar and global GPS network,J.Geophys.Res.,110,2005, doi:10.1029/2004JA010685.Huba,J.D.,G.Joyce,and J.A.Fedder,SAMI2(Sami2is Another Model of the Iono-sphere):A new low-latitude ionosphere model,J.Geophys.Res.,105,23,035–23,053, 2000.Huba,J.D.,K.F.Dymond,G.Joyce,S.A.Budzien,S.E.Thonnard,J.A.Fedder,and R.P.McCoy,Comparison of O+density from ARGOS data analysis and SAMI2model results,Geophys.Res.Lett.,29,2002,doi:10.1029/2001GL013089.Huba,J. D.,G.Joyce,and J. A.Fedder,Simulation study of mid-latitude iono-sphereﬂuctuations observed at Millstone Hill,Geophys.Res.Lett.,30,1943,2003, doi:10.1029/2003GL018018.Jakowski,N.,E.Putz,and P.Spalla,Ionospheric storm characteristics deduced from satellite radio beacon observations at three European stations,Ann.Geophys.,8,343, 1990.SWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-13 Kikuchi,T.,and T.Araki,Transient response of uniform ionosphere and preliminary reverse impulse of geomagnetic storm sudden commencement,J.Atm.Terr.Phys.,41,917–925,1979.Lu,G.,A.D.Richmond,R.G.Roble,and B.A.Emery,Coexistence of ionospheric positive and negative storm phases under northern winter conditions:A case study,J. Geophys.Res.,106,24,493,2001.Picone,J.M.,A.E.Hedin,D.P.Drob,and A.C.Aikin,NRLMSISE-00empirical modelof the atmosphere:Statistical comparisons and scientiﬁc issues,J.Geophys.Res.,107, 2002,doi:10.1029/2002JA009430.Rishbeth,H.,R.Gordon,D.Rees,and T.J.Fuller-Rowell,Modelling of thermospheric composition changes caused by a severe magnetic storm,J.Atmos.Terr.Phys.,51, 1283,1985.Vlasov,M.,M.C.Kelley,and H.Kil,Analysis of ground-based and satellite observationsof F-region behavior during the great magnetic storm of July15,2000,J.Atmos.Sol. Terr.Phys.,65,1223,2003.X -14SWISDAK ET AL.:POSITIVE STORMSIMULATIONSFigure 1.Schematic of the eﬀects of neutral winds and electric ﬁelds on the mid-latitude ionosphere.The colors merely suggest the variation of the density with altitude and do not represent the simulations.SWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-15Figure2.F-region electricﬁeld components and neutral winds above Millstone Hill on2April(blue)and3April(red).For both the east-west(E x,top panel)and north-south(E y,middle panel)components the lines denote the observations and the simulations.The right axis gives the magnitude of the E×B drift at330km due to each component.In both panels upward and poleward drifts are positive.For the meridional neutral winds (bottom panel)the solid lines show the velocities from HWM93and the dashed linesshow the observations.The right axis gives the projection of the wind speed onto thelocal magneticﬁeld.Positive values are northward.X-16SWISDAK ET AL.:POSITIVE STORM SIMULATIONSparison between observations(dashed lines)and simulation(solid)of the electron density(top)and temperature(bottom)at330km above Millstone Hill.Values from2April are shown in blue,3April in red.SWISDAK ET AL.:POSITIVE STORM SIMULATIONS X-17parison between observations(dashed lines)and simulation(solid)ofN m F2(top)and h m F2(bottom)above Millstone Hill.Values from2April are shown in blue,3April in red.X-18SWISDAK ET AL.:POSITIVE STORM SIMULATIONSFigure5.Electron density(top)and temperature(bottom)for simulations of3April. The observational data(dashed red)and normal simulation(solid red)are the same as in Figure3.For the dashed black line the simulated electricﬁeld of3April has been replaced with that of2April.For the dotted black line the electricﬁeld is normal but the neutral atmosphere and winds have their2April values.。