单板纳星电源系统能量平衡仿真

能量平衡是微纳卫星电源系统设计和考核的重要要求,在地面通常通过数值仿真进行评价。介绍单板纳星电源系统结构和特点;分别对太阳电池阵、蓄电池组和卫星负载进行数学建模;结合卫星姿态动力学进行能量平衡仿真,仿真结果可以实时反映卫星的功率变化、电池容量和能量平衡情况。电源系统在轨试验数据与仿真结果基本一致,证明所建模型是正确的,仿真方法有效。     

爆炸载荷作用下的船用吸能防护结构

重要舰船或舰船的重要部位采用吸能防护结构的必要性已逐渐被人们所认识和接受。防护结构性能好坏的主要指标是培构总能量吸收量和比耗能,本文分析了3种船用吸能防护结构在爆炸最荷作用下的破坏形式,给出了相应的能量吸收估算公式及计算蛄果,比较了等重量下不同防护结构的吸能量和比耗能,从而为船用吸能防护结构用于抗爆炸设计提供了依据和方法。     

舰船利用柴油机冷却水余热作吸收式制冷空调装置热源的研究

对某型舰利用６—１５０Ｃ柴油发电机冷却水余热作为低品位热源进行溴化锂吸收式制冷进行了热力计算和节能分析。计算及分析结果表明：利用６—１５０Ｃ柴油发电机组冷却水余热作为某型舰吸收式空调机组的热源是可行的,它不仅满足该型舰制冷量的要求,还具有明显的节能效果。     

填充式波纹夹层结构超高速撞击特性仿真

基于航天器空间碎片被动防护需求,对一种新型填充式波纹夹层结构进行超高速撞击仿真研究,分析超高速撞击过程以及结构的穿孔破坏情况和所形成的碎片云的特性,并与相同面密度Whipple结构进行对比。其撞击现象与Whipple结构相似,但其碎片云的头部速度小于Whipple结构,而径向膨胀最大速度和膨胀半角均大于Whipple结构。随撞击初速从3 km/s~10 km/s不断增大,波纹夹层结构的撞击穿孔尺寸变大,形状也更不规则。此外,结构中的填充树脂对碎片撞击能量的吸收贡献最大,后面板所吸收的能量所占比重较大,而前面板和波纹板对碎片撞击能量的吸收贡献较小。研究结果对空间碎片防护结构的设计具有一定的参考意义。     

Performance study of jute-epoxy composites/sandwiches under normal ballistic impact

This study is undertaken to explore the use of natural fiber Jute-epoxy (JE), Jute-epoxy-rubber (JRE) sandwich composite for ballistic energy absorption. Energy absorbed and residual velocities for these composites are evaluated analytically and through Finite Element Analysis (FEA). FE analysis of JE plates is carried out for different thicknesses (3, 5, 10 and 15 mm). JE plates and JRE sandwiches having the same thickness (15 mm) are fabricated and tested to measure residual velocity and energy absorbed. The analytical results are found to agree well with the results of FE analysis with a maximum error of 9%. The study on JE composite plate reveals that thickness influences the energy absorption. Experimental and FE analysis study showed that JRE sandwiches have better energy absorption than JE plates. Energy absorption of a JRE sandwich is about 71% greater than JE plates. Damages obtained from FEA and testing are in good agreement. SEM analysis confirms composites failed by fiber rupture and fragmentation.     

Between Man and Nature: The Enduring Wisdom of Sir Halford J. Mackinder

This article argues for the continued relevance of the work and theories of the British Geostrategist Sir Halford J. Mackinder (1861-1947). It asserts that commentators and scholars who seek to marginalise Mackinder have too often dismissed his theories without setting them in the context of their continued endorsement in crucial areas of the globe. After 1945, despite his theories being tainted by association with Nazi Germany and Imperial Japan, both Moscow and Washington recognised the utility of Mackinder’s work and tailored policy accordingly. The end of Cold War saw Mackinder fall out of favour as his model was deemed unsuitable for policy analysis by a number of influential thinkers. It is argued here that, in recent years, the arena of international politics has seen a rehabilitation of Mackinder, accompanied by a resurgence of interest in Geopolitics. Finally, the piece examines those areas of the contemporary globe where Mackinder’s influence is greatest.     

THE NPT

This article assesses the successes and failures of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) since its creation in 1968 by developing and applying a set of “metrics” to each of the NPT's substantive articles as well as to its withdrawal provisions. In light of this analysis, the article also puts forward some specific proposals for strengthening the NPT and its implementation, with a view to the debate and decisions at the upcoming 2010 NPT Review Conference. A concluding section turns explicitly to the 2010 NPT Review Conference and proposes pursuit of agreement on three NPT Action Plans: one for nonproliferation, one for peaceful uses, and one for nuclear disarmament. Combining vision and practicable steps, these Action Plans would set out a roadmap for action between the 2010 and the 2015 NPT Review Conferences. They could provide a foundation for substantive exchanges—in this case, on progress toward their implementation—during the preparations for the 2015 conference.     

Meeting the growing safeguards burden

ABSTRACT

The International Atomic Energy Agency (IAEA) faces challenges in fulfilling its safeguards mandate as a result of an expanding safeguards burden and a relatively static budget. This dilemma has been exacerbated by the additional burdens of implementing the Joint Comprehensive Plan of Action (JCPOA) in Iran, but would not go away if implementation of the JCPOA were to end. There are three main areas of opportunity for the Agency: (1) budgetary expansion tied to changes in staffing policies, (2) changes in safeguards approaches, and (3) technological innovation. Barriers and limitations are associated with each approach, and advancing any of them will face a difficult political environment in Vienna.     

“The major prize”: apartheid South Africa’s accession to the Treaty on the Non-Proliferation of Nuclear Weapons, 1988–91

ABSTRACT

This article focuses on the final years of South Africa’s nuclear-weapon program, particularly on the decision-making process leading up to the signature of the 1968 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) by the South African government in 1991. In August 1988, after two decades of defiance, negotiations between the apartheid government and the NPT depository powers (the United Kingdom, the United States, and the Soviet Union) ensued at the International Atomic Energy Agency (IAEA) in Vienna. Despite South Africa being the only state to give up its indigenously developed nuclear weapons and subsequently join the nonproliferation regime, little is known about how the national position on NPT accession and IAEA safeguards evolved. Research carried out in multiple archives using hitherto untapped primary sources and interviews with key actors from several countries show how domestic and regional political dynamics influenced Pretoria’s position on entering the nonproliferation regime. In the process, the F.W. de Klerk government managed to skillfully exploit international proliferation fears to advance its own agenda, thereby connecting South African NPT accession with that of the neighboring Frontline States coalition of Angola, Mozambique, Tanzania, Zambia, and Zimbabwe.