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181.
Nuclear energy is an integral part of China's energy strategy and will increasingly contribute to China's total energy supply. China has more than twenty civilian facilities, including power reactors, mines, and enrichment plants, to support its nuclear power program. As China operates more nuclear plants, more nuclear materials will be produced and stockpiled, and more nuclear facilities will be spread around the country. To ensure that this expanded network of nuclear facilities does not increase the risk that nuclear materials will be diverted or become the target of attack, China will need to develop more reliable domestic nuclear security strategies. China is also poised to become a major exporter of nuclear energy technology. China has committed to keeping nuclear technologies out of the hands of dangerous states and/or sub-state organizations, but in order to fulfill its nonproliferation obligations as well as its treaty-based commitment to share nuclear technologies, China will need to strengthen nuclear export controls and practices. This report examines and evaluates security measures at Chinese civilian nuclear power plants and suggests ways to improve them. It also reviews current export control policies and systems, identifies likely challenges to the expanding nuclear sector, and proposes possible solutions.  相似文献   
182.
Abstract

The United States Africa Command (AFRICOM) has been a military success but a strategic messaging failure. The United States’ relationships across Africa cannot be boiled down to military affairs. This paper argues that Africa has many more opportunities than challenges and thus requires a more balanced foreign policy solution from Washington DC than a new military command. For the military engagement that does need to take place, a more low-profile approach would benefit the United States in Africa.  相似文献   
183.
NUCLEAR ISLANDS     
Current International Atomic Energy Agency safeguards do not provide adequate protection against the diversion to military use of materials or technology from certain types of sensitive nuclear fuel cycle facilities. In view of highly enriched uranium's relatively greater ease of use as a nuclear explosive material than plutonium and the significant diseconomies of commercial spent fuel reprocessing, this article focuses on the need for improved international controls over uranium enrichment facilities as the proximate justification for creation of an International Nuclear Fuel Cycle Association (INFCA). In principle, the proposal is equally applicable to alleviating the proliferation concerns provoked by nuclear fuel reprocessing plants and other sensitive nuclear fuel cycle facilities. The INFCA would provide significantly increased nonproliferation assurance to its member states and the wider international community by holding long-term leasehold contracts to operate secure restricted zones containing such sensitive nuclear facilities.  相似文献   
184.
ABSTRACT

While nuclear suppliers compete in markets, they simultaneously partner in other fields. This produces a delicate relationship between civilian nuclear programs and nuclear weapon proliferation. This study explores how export competition affects suppliers’ conditions of supply related to nuclear nonproliferation. We investigated three export cases (India, North Korea, and South Korea) and identified four effects that competition has on the conditions of supply related to nonproliferation. First, under highly competitive conditions, suppliers might hesitate to enforce the conditions of supply to avoid negotiation conflicts with recipients. Second, suppliers focus on politically and economically attractive recipients while mostly ignoring unattractive ones, perhaps allowing proliferation problems to fester out of view in marginal states. Third, suppliers can build consensus on the conditions of supply to avoid being the only party experiencing negotiation conflicts. Fourth, suppliers can constrain others from relaxing the conditions of supply to maintain economic benefits and nonproliferation norms. The first two effects accelerate proliferation while the last two promote nonproliferation. Although the extent of these effects can vary with changes in nonproliferation norms, they can contribute to our understanding of the relationship between nonproliferation and civilian nuclear programs.  相似文献   
185.
In the past, Germany reprocessed a significant amount of its spent nuclear fuel, partly on its own territory but mostly as a customer of British and French reprocessing plants. In mid-2005, Germany stopped this practice, banning new transports of spent fuel for reprocessing—although the already-exported material would be allowed to be reprocessed and recycled in German reactors as mixed-oxide (MOX) fuel. In total, about 6,500 tonnes of heavy metal have been contracted for reprocessing, but a significant portion of this material has neither been reprocessed nor recycled as MOX fuel in German reactors. Due to the complex import-export history and the partly nontransparent information policy of the German government and utilities, a comprehensive and up-to-date plutonium balance for Germany is not publicly available. This report provides an assessment of Germany's plutonium inventory (stored domestically or abroad) based on open-source information. Special attention is paid to the issue of whether the entire inventory of separated plutonium can be completely irradiated in German nuclear reactors before the last of them are shut down in 2022. The authors conclude that Germany's stock of plutonium waiting to be recycled was about 12.2 tonnes as of 2010; this plutonium should be completely re-imported from the United Kingdom and France by 2017. Germany's MOX-consumption capacities should be sufficient to irradiate the remaining plutonium, although further delays are expected that could leave Germany with an inventory of separated (unirradiated) plutonium.  相似文献   
186.
为了满足偏远岛屿小功率用电保障需求,根据波浪能特点,提出一种新型漂浮式微型波力发电装置。利用重锤惯性定心原理,建立浮动"机架",解决漂浮体内部相对固定问题;采用机-电直接转换系统,提高波浪能的利用效率;研究系统的原理与结构,分析系统的功能特点和主要运动参数。研究结果表明,漂浮式微型波力发电装置具有结构原理新颖、传动效率高、传动质量好与轻巧便携等优点。该研究为漂浮式微型波力发电装置的研发与应用奠定了基础。  相似文献   
187.
航空吊放声纳是反潜作战主要搜潜设备之一,其主动工作方式暴露范围也是搜潜战术运用的重要参数。基于均方声压声纳方程修正了相关参数,得到了声能声纳方程各项参数定义,结合高斯束射线Bellhop模型,研究了吊放声纳主动方式暴露距离估算方法,针对潜艇两种声纳类型工作特性,进行了仿真和分析。仿真结果表明,在潜艇侦察声纳工作时,吊放声纳主动方式暴露距离明显加大。  相似文献   
188.
由于过模Ku波段高功率微波返波管通常输出TM0n混合模式,在保证较高能量转换效率的条件下,难以同时兼顾其输出模式的纯度,而辐射终端为达到理想发射效果又要求单一模式馈入,这就给输出混合模式微波源的实际应用带来了困难。针对这一技术难点,提出一种结构紧凑的TM0n-TM01(n≤3)混合模式转换器的设计方法,实现在高功率容量条件下和较宽频带范围内,高效地将TM0n混合模式转换为单一的TM01模,降低了此类高频段高功率微波源模式纯化设计的难度。  相似文献   
189.
《防务技术》2022,18(11):2000-2007
The design of astonishing combinations of benzoxazine resins with various fillers is nowadays of great interest for high quality products, especially in ballistic armors. The objective of this study is to investigate a new hybrid material prepared as multi-layered composite plate by hand lay-up technique. Different composites were manufactured from Kevlar fabrics reinforced polybenzoxazine, which was filled with silane treated microcrystalline cellulose (MCC Si) at various amounts in the interlayers. The developed materials were tested for their flexural, dynamic mechanical and ballistic performance. The aim was to highlight the effect of adding different amounts of MCC Si on the behavior of the different plates. Compared to the baseline, the dynamic mechanical and bending tests revealed an obvious decrease of the glass transition of 21 °C and a notable increase in storage modulus and flexural strength of about 180 %and17%, respectively, upon adding 1% MMC Si as filler. Similarly, the ballistic test exhibited an enhancement in kinetic energy absorption for which the composite supplemented with 1% MCC Si had the maximal energy absorption of 166.60 J. These results indicated that the developed panels, with interesting mechanical and ballistic features, are suitable to be employed as raw materials to produce body armor.  相似文献   
190.
探月飞船升阻比较低,为实现长纵程飞行,必须采用跳跃式再入方式。在跳跃式再入轨迹在线规划或预测制导中,如何快速准确地预测初次再入段纵程是一个非常关键的问题。针对这一问题,研究提出一种解析预测方法:利用匹配渐进展开方法得到再入纵向运动方程的闭型近似解;将初次再入段轨迹分为三段,第一段采用高度作为积分自变量,并利用复合梯形公式得到纵程,第二段和第三段分别采用二次多项式来拟合阻力加速度-能量剖面,根据近似解结果反解出多项式系数,并将得到的阻力加速度倒数-能量函数进行积分,得到第二段和第三段的纵程;对解析预测方法的精度和计算效率进行分析,结果表明该方法计算精度较高,速度快,可用于跳跃式再入轨迹的在线规划和制导。  相似文献   
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