一篇写的非常详细的综述文章，值得认真读几遍！PDF下载地址：http://ddl.escience.cn/f/yHs0 详细介绍了从large-global-scale to small-local scale 过程中 MHD, Test particle, PIC方法各自的特点、优势及局限性，只可惜没涉及LBM。 Recent Advances in Understanding Particle Acceleration Process in Solar Flares Recent Advances in Understanding Particle Acceleration Processes in Solar Flares Valentina V. Zharkova , Karpar Arzner , Arnold O. Benz , Philippa Browning , Cyril Dauphin , A. Gordon Emslie , Lyndsay Fletcher , Eduard P. Kontar , Gottfried Mann , Marco Onofri , Vahe Petrosian , Rim Turkmani , Nicole Vilmer , Loukas Vlahos (Submitted on 11 Oct 2011 ( v1 ), last revised 23 Oct 2011 (this version, v3)) We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered. Comments: This is a chapter in a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011) Subjects: Solar and Stellar Astrophysics (astro-ph.SR) ; Plasma Physics (physics.plasm-ph); Space Physics (physics.space-ph) DOI: 10.1007/s11214-011-9803-y Cite as: arXiv:1110.2359 (or arXiv:1110.2359v3 for this version)
导演: 扎克·佩恩 类型: 纪录片 制片国家/地区: 美国 语言: 英语 IMDb链接: tt3715406 About the recent dig in New Mexico where they uncovered a large amount of Atari games that were liquidated from Atari’s old plant in El Paso, Texas. Around 700,000 games in total are buried in the landfill, including games like Missile Command, Haunted House, Centipede, Asteroids and many others. 下载地址： http://page92.ctfile.com/file/138646154
点击 On line listening This is the VOA Special English Health Report. Old age may not sound exciting. But recent findings offer good news for older people and for people worried about getting older. Researchers found that people become happier and experience less worry after they reach the age of fifty. In fact, they say by the age of eighty-five, people are happier with their life than they were when they were eighteen years old. The findings came from a survey of more than three hundred forty thousand adults in the United States. The Gallup Organization questioned them by telephone in two thousand eight. At that time, the people were between the ages of eighteen and eighty-five. The researchers asked questions about emotions like happiness, sadness and worry. They also asked about mental or emotional stress. Arthur Stone in the Department of Psychiatry and Behavioral Science at Stony Brook University in New York led the study. His team found that levels of stress were highest among adults between the ages of twenty-two and twenty-five. The findings showed that stress levels dropped sharply after people reached their fifties. Happiness was highest among the youngest adults and those in their early seventies. The people least likely to report feeling negative emotions were those in their seventies and eighties. The study also showed that men and women have similar emotional patterns as they grow older. However, women at all ages reported more sadness, stress and worry than men. The findings appeared in the Proceedings of the National Academy of Sciences. Researchers say they do not know why happiness increases as people get older. One theory is that, as people grow older, they grow more thankful for what they have and have better control of their emotions. They also spend less time thinking about bad experiences. Professor Stone says the emotional patterns could be linked to changes in how people see the world, or maybe even changes in brain chemistry. The researchers also considered possible influences like having young children, being unemployed or being single. But they found that influences like these did not affect the levels of happiness and well-being related to age. And that's the VOA Special English Health Report, written by Brianna Blake. Tell us what you think about the relationship between happiness and age. You can post comments on our website, http://www.hxen.com , or on Facebook and Twitter at VOA Learning English. I'm Barbara Klein. 音频下载： 20110824b.mp3 同步字幕： 20110824b.lrc
Papers on the Community Structure Topics : A recent survey of Fortunato (2010) Finding statistically significant communities in networks, A. Lancichinetti, F. Radicchi, J.J. Ramasco and S. Fortunato Overlapping Communities in Dynamic Networks: Their Detection and Mobile Applications, N. P. Nguyen, T. N. Dinh, S. Tokala, and M. T. Thai, (Mobicom 2011) FacetNet: A Framework for Analyzing Communities and Their Evolutions in Dynamic Networks, Y.-R. Lin, Y. Chi, S. Zhu, H. Sundaram, and B. L. Tseng, (WWW 2008) Graphscope: A parameter-free mining of large time-evolving graphs, J. Sun, C. Faloutsos, S. Papadimitriou, and P. S. Yu, (KDD 2007) Community Structure in Time-Dependent, Multiscale, and Multiplex Networks, P. J. Mucha, T. Richardson, K. Macon, M. A. Porter, and J.-P. Onnela, (Science 2010) Discovering Network Structure Beyond Communities, T. Nishikawa and A. E. Motter, (Nature 2011) Algorithm for parametric community detection in networks, A. Bettinelli, P. Hansen, and L. Liberti, (Physical Review E, 2012) A markov random walk under constraint for discovering overlapping communities in complex networks, D. Yin, B. Yang, C. Baquero, D. Liu, D. He, and J. Liu, (J. STATE MECH 2011) Community Discovery and Profiling with Social Messages, W. Zhou, H. Jin, and Y. Liu, (KDD 2012) Vertex neighborhoods, low conductance cuts, and good seeds for local community methods, D. Gleich and C. Seshadhri (KDD 2012) Community Detection in Dynamic Social Networks: A Random Walk Approach, L.-C. Huang, T.-J. Yen, and S. T. Chou (ASONAM 2011) Community Detection in Incomplete Information Networks, W. Lin et. al (WWW 2012) Using Content and Interactions for Discovering Communities in Social Networks, M. Sachan, D. Contractor, T. Faruquie, and L. V. Subramaniam (WWW 2012)
P. Zhao, J. Zhang, Y. Yuan, J. Dong , S. L., and X. Zhang, "In-line polarization-dependent microfiber interferometers and their applications in UWB signal generation," Opt. Express,in press, 2013 S. Tan, J. Dong , and X. Zhang, "Optical Computation System for Solving Differential Equations Based on Optical Intensity Differentiator," Opt. Express, in press, 2013. J. Dong , A. Zheng, D. Gao, S. Liao, L. Lei, D. Huang, and X. Zhang, "High order photonic differentiator employing on-chip cascaded microring resonators," Optics Letters,vol. 38, pp. 628–630, 2013. J. Dong , A. Zheng, D. Gao, L. Lei, D. Huang, and X. Zhang, "Compact, flexible and versatile photonic differentiator using silicon Mach-Zehnder interferometers," Opt. Express, in press, 2013. J. Dong , A. Zheng, D. Gao, D. Huang, and X. Zhang, "High-order Photonic Differentiator using On-chip Cascaded Mach-Zehnder Interferometers," OFC/NFEOC, Anaheim, CA, USA,OW3D.6, 2013. J. Dong , L. Liu, D. Gao, Y. Yuan, A. Zheng, T. Yang, and X. Zhang, "Compact notch microwave photonic filters using on-chip integrated microring resonators," Photonics Journal, in press, 2013. Y. Zhang, J. Dong, L. Lei, H. He, Y. Yu, and X. Zhang, "Reconfigurable Four-Input Photonic Logic Minterms and Maxterms Generation Using SOAs," Photonics Technology Letters, IEEE, vol. 24, pp. 985-987, 2012. Y. Yu, J. Dong , X. Li, and X. Zhang, "UWB Monocycle Generation and Bi-phase Modulation Based on Mach-Zehnder Modulator and Semiconductor Optical Amplifier," Photonics Journal, vol. 4, pp. 327-339, 2012. B. Luo, T. Yang, J. Dong , Y. Yu, D. Huang, and X. Zhang, "All-Optical Millimeter-Wave Ultrawideband Signal Generation Using a Nonlinear Optical Loop Mirror," Photonics Journal, IEEE, vol. 4, pp. 350-356, 2012. B. Luo, J. Dong , Y. Yu, and X. Zhang, "Bandwidth-tunable single-carrier UWB monocycle generation using a nonlinear optical loop mirror," Photonics Technology Letters, vol. 24, pp. 1646 - 1649, 2012. B. Luo, J. Dong, Y. Yu, T. Yang, and X. Zhang, "Photonic generation of ultra-wideband doublet pulse using a semiconductor-optical-amplifier based polarization-diversified loop," Opt. Lett., vol. 37, pp. 2217-2219, 2012. L. Lei, J. Dong, Y. Yu, S. Tan, and X. Zhang, "All-Optical Canonical Logic Units-Based Programmable Logic Array (CLUs-PLA) Using Semiconductor Optical Amplifiers," Journal of lightwave technology, vol. 30, pp. 3532-3539, 2012.
Preface In recent years, Russia and China have urged the negotiation of an international treaty to prevent an arms race in outer space. The United States has responded by insisting that existing treaties and rules governing the use of space are sufficient. The standoff has produced a six-year deadlock in Geneva at the United Nations Conference on Disarmament, but the parties have not been inactive. Russia and China have much to lose if the United States were to pursue the programs laid out in its planning documents. This makes probable the eventual formulation of responses that are adverse to a broad range of U.S. interests in space. The Chinese anti-satellite test in January 2007 was prelude to an unfolding drama in which the main act is still subject to revision. If the United States continues to pursue the weaponization of space, how will China and Russia respond, and what will the broader implications for international security be? The American Academy called upon two scholars to further elucidate answers to these questions and to discuss the consequences of U.S. military plans for space. Pavel Podvig, a research associate at the Center for International Security and Cooperation at Stanford University and former researcher at theMoscow Institute of Physics and Technology, discusses possible Russian responses, given their current capabilities and strategic outlook. Hui Zhang, a research associate at the John F. Kennedy School of Government at Harvard University, considers Chinese responses. Each scholar suggests that introducing weapons into space will have negative consequences for nuclear proliferation and international security. As Podvig points out, Russia’s main concern is likely to be maintaining strategic parity with the United States. This parity will be destroyed by the deployment of weapons in space, making a response from Russia likely. Podvig writes, “Russia does not have many options for the development of its own weapon systems in space or for its reaction to the development of this capability by other countries. . . . However, this does not mean that there will be no reaction.” He suggests that Russia will be more likely to undertake other countermeasures such as extending the life of its ballistic missiles, measures that are “the most significant and dangerous global effects of new military developments, whether missile defense or space-based weapons.” Zhang arrives at similar conclusions. He describes how U.S. plans will negatively affect peaceful uses of outer space, disrupting current civilian and commercial initiatives, but focuses on a much greater concern among Chinese officials—that actions by the United States in space will result in a loss of strategic nuclear parity. China’s options for response, as detailed by Zhang, include building more ICBMs, adopting countermeasures against missile defense, developing ASAT weapons, and reconsidering China’s commit ments on arms control. Thus introducing weapons into space would destabilize the already vulnerable international non-proliferation regime. Zhang concludes, “U.S. space weaponization plans would have potentially disastrous effects on international security and the peaceful use of outer space. This would not benefit any country’s security interests.” These papers are part of the American Academy’s “Reconsidering the Rules of Space” project. The project examines the implications of U.S. policy in space from a variety of perspectives, and considers the inter national rules and principles needed for protecting a long-term balance of commercial, military, and scientific activities in space. The project is producing a series of papers, intended to inform public discussion of legitimate uses of space, and induce a further examination of U.S. official plans and policies in space. Other papers consider the physical laws governing the pursuit of security in space (spring 2005), challenges posed to the United States space program by current policies (spring 2005), and the possible elements of a more comprehensive space security system (forthcoming). In May 2002, the American Academy convened a workshop on Chinese Perceptions of U.S. Space Plans to support Hui Zhang’s work on his essay. Pavel Podvig’s essay was reviewed at a workshop at the University of Maryland in January 2005.We join the authors in thanking the participants in these workshops for their participation and insights. We also thank five anonymous reviewers for their comments on the papers.We acknowledge the excellent work of Helen Curry, Phyllis Bendell, and Anne Read in producing this report.We are, most of all, grateful to the authors for applying their knowledge and experience to these important issues. The Rules of Space project is supported by a generous grant from the Carnegie Corporation of New York. We thank the Carnegie Corporation for its support and Patricia Nicholas for her assistance. John Steinbruner Carl Kaysen MartinMalin University of Maryland Massachusetts Institute American Academy of Technology of Arts and Sciences 原文见 http://www.amacad.org/publications/militarySpace.pdf
The United States has been widely blamed for the recent financial crisis. As the U.S. economy floundered and China continued to grow in the great recession of 2008—2009, Chinese authors launched ‘‘a flood of declinist commentary about the United States.’’ One expert claimed that the high point of U.S. power projection was 2000. The Chinese were not alone in such statements. Goldman Sachs advanced the date at which it expects the size of the Chinese economy to surpass the U.S. economy to 2027. In a 2009 Pew Research Center poll, majorities or pluralities in 13 of 25 countries believed that China will replace the United States as the world’s leading superpower. Even the U.S. government’s National Intelligence Council projected in 2008 that U.S. dominance would be ‘‘much diminished’’ by 2025. President Dmitri Medvedev of Russia called the 2008 financial crisis a sign that the United States’ global leadership is coming to an end, and even a sympathetic observer, Canadian opposition leader Michael Ignatieff, suggested that Canada should look beyond North America now that the ‘‘the noon hour of the United States and its global dominance are over.’’ One should be wary, however, of extrapolating long-term trends from cyclical events, while being aware of misleading metaphors of organic decline. Nations are not like humans with predictable life spans. For example, after the United Kingdom lost its American colonies at the end of the eighteenth century, Horace Walpole lamented its reduction to ‘‘as insignificant a country as Denmark or Sardinia.’’ He failed to foresee that the industrial revolution would give the United Kingdom a second century of even greater ascendency. Likewise, Rome remained dominant for more than three centuries after the apogee of Roman power. Even then, Rome did not succumb to the rise of another state, but died a death of a thousand cuts inflicted by various barbarian tribes. Indeed for all the fashionable predictions of Brazil, China, or India surpassing the United States in the next decades, the greater threats may come from cuts from modern barbarians and non-state actors. Of course, the financial crisis has had epochal effects on what might be called ‘‘the Wall Street model.’’ The poor performance of Wall Street institutions and Washington regulators has cost New York a good deal in terms of its soft power, or the attractiveness of its economic model. In terms of institutional change, the five major investment banks (Bear Stearns, Goldman Sachs, Lehman Brothers, Merrill Lynch, and Morgan Stanley) are gone or changed in shape, and the financial mess they helped create produced a sharp recession and new demands for political regulation. Ironically, two years after the collapse which Europeans blamed on the United States, Washington moved more rapidly on reform than Europe which ‘‘has itself been nearly overwhelmed by a crisis of its own — caused by sovereign rather than personal indebtedness — and the United States has begun growing again, albeit uncertainly.’’ It is still too early to judge the long-term effects of the crisis on U.S. power, but the blow need not be fatal if, in contrast to Japan in the 1990s, Washington moves quickly to absorb the losses and limit the damage. The World Economic Forum still rates the U.S. economy as the world’s second most competitive (after Switzerland) because of its labor market flexibility, higher education, political stability, and openness to innovation, while China is ranked number 29. In areas like biotechnology, nanotechnology, and the second generation of the World Wide Web, the United States still leads. Nevertheless, while few expect China to surpass the United States in military power in the next two decades, many still see the crisis as transformative in economic and soft power relations. It is important, therefore, to focus on the implications of the crisis in order to analyze the power relations between China and the United States. 原文见 http://www.tandfonline.com/doi/pdf/10.1080/0163660X.2010.516634
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