面向新世纪的粒子图像测速

一种综述粒子图像测速(Particle Image Velocimetry)的非接触、瞬时、动态、全流场的和本质上是直接的速度场测量技术,成为当今最实用和非常有潜力的流体力学全流场观测(Full Flow Field Observation & Measurement)技术.回顾和展望PIV(包括DPIV,SPIV,HPIV等)及其应用的进展和前景.面临新世纪,PIV技术有望最终攻克一个容积的三维速度场时间历程(3Dt-3C)的观测和推动流体力学进入十分活跃的新时期.     

钱杭评《中国宗族史研究入门》

以编撰角度多方面解读《中国宗族史研究入门》。该书具有一定教学实用价值,是了解当前学术界中国宗族史研究动态、研究方法等方面的一本学术入门书籍。对于我国人才培养模式的优化、中国宗族史研究的深入化等方面将起到积极的推动作用,为读者系统了解历代具有代表性的宗族研究成果提供借鉴和帮助。     

科学评价党史，正确处理历史遗留问题——论邓小平指导党史研究的基本原则

本文系统阐述了邓小平同志指导党史研究、正确处理历史遗留问题的六大原则：“向前看”原则;“宜粗不宜细”原则;“有错必纠”原则;客观性原则;分析个人责任与分析复杂背景相结合的原则;总结成功经验与汲取失败教训相结合的原则。文章深入分析了上述原则的内涵、要求及其意义。     

Precursor to an African Space Agency: Commentary on Dr Peter Martinez “Is there a need for an African Space Agency?”

In 2012 a working group was established to formulate the African space policy and strategy which would lead to the establishment of an African Space Agency (ASA). Dr Peter Martinez asserts in his article “Is there a need for an African Space Agency?” [1] that the arguments that have been posited in support of an ASA are flawed; namely the arguments of the existing example of the European Space Agency (ESA), and that an ASA would lead to fostering competition, synergy, industrial development and capacity building. While this viewpoint agrees that all the perfect conditions may not exist at present for the creation of an ASA, it addresses some of the issues raised by Martinez, and proposes ideas to foster intra-regional cooperation.     

Transforming solar system exploration: The origins of the Discovery Program, 1989–1993

The Discovery Program is a rarity in the history of NASA solar system exploration: a reform program that has survived and continued to be influential. This article examines its emergence between 1989 and 1993, largely as the result of the intervention of two people: Stamatios “Tom” Krimigis of the Johns Hopkins University Applied Physics Laboratory (APL), and Wesley Huntress of NASA, who was Division Director of Solar System Exploration 1990–92 and the Associate Administrator for Space Science 1992–98. Krimigis drew on his leadership experience in the space physics community and his knowledge of its Explorer program to propose that it was possible to create new missions to the inner solar system for a fraction of the existing costs. He continued to push that idea for the next two years, but it took the influence of Huntress at NASA Headquarters to push it on to the agenda. Huntress explicitly decided to use APL to force change on the Jet Propulsion Laboratory and the planetary science community. He succeeded in moving the JPL Mars Pathfinder and APL Near Earth Asteroid Rendezvous (NEAR) mission proposals forward as the opening missions for Discovery. But it took Krimigis's political skill and access to Sen. Barbara Mikulski in 1993 to get the NEAR into the NASA budget, thereby likely ensuring that Discovery would not become another one-mission program.     

中美技术状态管理军用标准发展史和对比

为了借鉴美国技术状态管理军用标准先进经验,回顾了美国技术状态管理军用标准从无到有、从杂乱无序到协调一致、从单一军标到军民融合的发展历史,我国标准从《质量管理条例》到建立技术状态管理国军标的发展历史,以及国内技术状态管理标准的应用现状。通过对中美技术状态管理军用标准体系的对比,发现我国的标准体系的范围、深度、数量和质量相对美标还存在较大差距:国内标准以原则要求为主,缺少详细要求内容及实践指南类标准文件,未能适应数字化技术的发展,制定数据交换和互操作性标准。提出编写技术状态管理指南和手册文件,完善技术状态管理标准体系,并统一技术状态管理系统平台,建立符合我国国情的技术状态管理数字化环境的建议。     

Cubesats: Cost-effective science and technology platforms for emerging and developing nations

The development, operation, and analysis of data from cubesats can promote science education and spur technology utilization in emerging and developing nations. This platform offers uniquely low construction and launch costs together with a comparative ubiquity of launch providers; factors that have led more than 80 universities and several emerging nations to develop programs in this field. Their small size and weight enables cubesats to “piggyback” on rocket launches and accompany orbiters travelling to Moon and Mars. It is envisaged that constellations of cubesats will be used for larger science missions. We present a brief history, technology overview, and summary of applications in science and industry for these small satellites. Cubesat technical success stories are offered along with a summary of pitfalls and challenges encountered in both developed and emerging nations. A discussion of economic and public policy issues aims to facilitate the decision-making process for those considering utilization of this unique technology.     

Antikythera Calculator advances modern science of 19 centuries

The Greek astronomic calculator, discovered in the depth of the sea in a naval wreckage of the 1st century B.C. in front of the island of Antikythera, is the most amazing among the archaeological discoveries of last century. The mechanism immediately appeared like a device out of its time. After years of study this devise is still provoking a discussion between scientists and archaeologists because of the complexity and the modernity of the scientific knowledge the work presupposes. Its epicyclical gearings show the high level of the scientific culture reached in that period of history.