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181.
一种新型结构吸波材料的制备 总被引：2，自引：0，他引：2
介绍了阻抗匹配设计原理。自制了三种导电纤维,分别织成正交平纹布,通过优化设计,采用简单层式结构,以酚醛为基体,制备出接近实用水平的多层结构吸波材料。该材料厚3.2mm,密度1.38g/cm3,面密度4.42kg/m2;在8.4GHz～18GHz反射率小于-10dB;弯曲强度173MPa,弯曲模量12.5GPa。 相似文献
182.
183.
强电磁脉冲通过电子设备表面耦合进入内部将产生显著的破坏作用,而等离子体作为一种特殊的电磁介质,具有屏蔽强电磁脉冲的能力,因此基于等离子体的强电磁脉冲防护研究具有重要意义。利用CST软件仿真分析了核电磁脉冲模拟器工作空间的电场分布。进行了核电磁脉冲对单片机的干扰和破坏效应辐照研究,得到了其对MF-51-1型单片机的干扰和破坏阈值分别在10 kV/m和18 kV/m左右。实验研究了单层等离子体阵列对核电磁脉冲的防护性能,能量衰减均在10 dB以上。实验结果表明,等离子体具有强电磁脉冲防护的能力。 相似文献
184.
评价模式是核事故应急评价系统的核心．在理论分析的基础上,建立了适合基地特点的潜艇核事故应急评价模式及参数,并通过假想事故对所建立的评价模式进行了校核．结果表明,该模式具有良好的可靠性和可行性,适合基地的特点,满足核潜艇核事故应急评价的要求．根据所建模式,还编制了一套实用、可靠、灵活、方便的应用软件． 相似文献
185.
The dielectric constant (DC) is one of the key properties for detection of threat materials such as Improvised Explosive Devices (IEDs). In the present paper, the density functional theory (DFT) as well as ab-initio approaches are used to explore effective methods to predict dielectric constants of a series of 12 energetic materials (EMs) for which experimental data needed to experimentally determine the dielectric constant (refractive indices) are available. These include military grades energetic materials, nitro and peroxide compounds, and the widely used nitroglycerin. Ab-initio and DFT calculations are conducted. In order to calculate dielectric constant values of materials, potential DFT functional combined with basis sets are considered for testing. Accuracy of the calculations are compared to experimental data listed in the scientific literature, and time required for calculations are both evaluated and discussed. The best functional/basis set combinations among those tested are CAM-B3LYP and AUG-cc-pVDZm, which provide great results, with accuracy deviations below 5% when calculated results are compared to experimental data. 相似文献
186.
Covell Meyskens 《The Nonproliferation Review》2019,26(5-6):499-517
ABSTRACTThis article examines Chinese views of North Korea’s nuclear-weapon program during the Donald J. Trump administration. It shows that China has portrayed itself as a responsible country that promotes regional stability, unlike the United States, which has engaged in military brinkmanship with North Korea. Some Chinese foreign-policy experts have asserted that Beijing should back Pyongyang in the event of war because of their shared history of humiliation by great powers, while others have favored working with other regional partners. Another theme in Chinese discourse about North Korea is that Pyongyang is an impetuous, ungrateful regime that impedes Beijing’s ability to attain its core interests of regional stability, economic development, and heightened global influence. This negative assessment of North Korea drove Beijing’s endorsement of stricter UN sanctions in 2017. While Beijing has punished Pyongyang for its wayward policies, China responded favorably to North Korea’s decision in April 2018 to stop nuclear tests and partake in international dialogue. Beijing seeks to help Pyongyang gradually disarm and develop its economy within a Chinese-led East Asian order. The article concludes by explaining how Beijing’s recent, more positive view of Pyongyang is likely to affect its support for American efforts to dismantle North Korea’s nuclear-weapon program. 相似文献
187.
Ulrich Kühn 《The Nonproliferation Review》2019,26(1-2):155-166
The end of the 1987 Intermediate-range Nuclear Forces (INF) Treaty has the potential to plunge Europe and NATO into deep crisis. Russia’s continued violation coupled with the Donald J. Trump administration’s desire to balance against Moscow and Beijing could force a new missile debate on Europeans. Even though Washington is trying to assuage its allies, the specter of another round of INF missile deployments to Europe is not unrealistic. Meanwhile, NATO’s European members face a dilemma. Some want NATO to resolutely push back against Russia. Others want to avoid a new deployment debate, at almost all costs. The Kremlin will use these cleavages to weaken NATO. If not carefully handled, NATO’s response to the Russian missile buildup could lead to domestic turmoil in a number of European states and render the alliance ineffective for a prolonged period. Europeans need to act now and voice their preferences in the military and diplomatic domains. A number of different military options are available, below the level of deploying new INF missiles in Europe. However, Europeans need to consider trade-offs regarding crisis and arms-race stability. At the same time, it will be up to European capitals to conceptualize a new arms-control framework for the post-INF world, one that takes into account today’s geopolitical realities and the entanglement of modern conventional and nuclear forces. Given the Trump administration’s loathing of arms control, concepts of mutual restraint may well have to wait for the next US administration. In any case, that should not stop Europeans from taking on more responsibility for their own security. 相似文献
188.
《防务技术》2019,15(3):319-325
Nanothermites (metal oxide/metal) can offer tremendously exothermic self sustained reactions. CuO is one of the most effective oxidizers for naonothermite applications. This study reports on two prospectives for the manufacture of CuO nanoparticles. Colloidal CuO particles of 15 nm particle size were developed using hydrothermal synthesis technique. Multiwalled carbon nanotubes (MWCNTs) with surface are 700 m2/g was employed as a substrate for synthesis of CuO-coated MWCNTs using electroless plating. On the other hand, aluminium particles with combustion heat of 32000 J/g is of interest as high energy density material. The impact of stoichiometric nanothermite particles (CuO/Al & Cuo-coated MWCNTs/Al) on shock wave strength of Al/TNT nanocomposite was evaluated using ballistic mortar test. While CuO-coated MWCNTs decreased the shock wave strength by 15%; colloidal CuO enhanced the shock wave strength by 30%. The superior performance of colloidal CuO particles was correlated to their steric stabilization with employed organic solvent. This is the first time ever to report on fabrication, isolation, and integration of stablilized colloidal nanothermite particles into energetic matrix where intimate mixing between oxidizer and metal fuel could be achieved. 相似文献
189.
Neil Narang 《The Nonproliferation Review》2013,20(3-4):457-468
ABSTRACTThe popular use of the term “weapons of mass destruction” (WMD) can be understood to imply a relationship between nuclear, chemical, and biological weapons proliferation insofar as it assumes that the separate weapons technologies can be usefully grouped into a single analytic category. This article explores whether WMD is actually a useful construct. It begins by reviewing the literature on nuclear, chemical, and biological weapons proliferation, including a recent study that sought to estimate the relationship between the pursuit and acquisition of these different weapons. It then explores some policy inferences that academics and policy makers may be tempted to draw from these studies, particularly regarding the Barack Obama administration's pursuit of deep nuclear reductions. It argues that many of these policy inferences are premature at best and misleading at worst. It concludes with a call for additional research into the causes and consequences of chemical and biological weapons proliferation, and a call for scholars to remain cautious in their desire to draw premature policy implications from their studies in order to be “policy relevant.” 相似文献
190.
ABSTRACTWhile 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