拦截战术导弹制导的弹道稳定性分析

针对一种拦截战术弹道导弹制导规律的特点,以经典的劳斯稳定判据为依据,构想了对其弹道稳定性的分析方法。从弹道稳定性的要求出发,对制导控制系统相关参数选择的原则给出了定量的结果。最后探讨了该制导方法的工程应用前景。     

非晶态Ni-P合金化学镀镀液的稳定性研究

采用PdCl2溶液的稳定性试验方法,对非晶态Ni-P合金化学镀镀液(ZFHN防腐蚀镀液)的稳定性和试验条件进行了关系曲线测试及分析.规定和提出了其试验条件和最佳控制参数;试验镀液中PdCl2的最佳浓度是2.4 mg/L、可靠的pH值范围为4.0～5.0.温度、搅拌、PdCl2用量、镀液pH值是决定镀液稳定时间的重要试验条件和试验偏差大的主要因素.研究镀液的稳定性高、组分协同稳定性好,稳定试验时间大于3 min.     

强磁场环境模拟系统线圈支架设计及力学仿真

强电磁冲击环境的核心执行机构是线圈,除保障强磁环境发生线圈的电磁特性外,还须确保线圈支架具有充足的机械特性。在完成对线圈磁电设计的基础上,根据线圈的三维结构图、材料配置、质量分布、各零部件之间连接方式以及线圈固定方式等,建立线圈支架结构整体系统有限元计算模型,对线圈支架系统进行静力、稳定性数值计算分析,并校核联接件强度,为线圈支架结构提供参考依据。对实用大型强磁冲击系统所用线圈整体的力学结构进行设计分析,应用背景较新,且仿真计算过程严格按照实际搭建尺寸进行,具有高度的一致性,为后续搭建强磁环境发生装置提供坚实基础。     

影响内蒙古边境地区稳定发展的问题及其对策

改革开放以来 ,内蒙古边境地区社会稳定与经济发展都有了长足的进步。作为公安边防机关 ,要充分发挥其职能作用 ,继续加大工作力度 ,严厉打击各种非法活动。     

无人机配载弹射式导弹静稳定性分析

通过刚体飞行六自由度动力学方程建立弹射式导弹初始段无控飞行模型,并结合弹射装置动力模型和导弹发动机推力模型进行仿真计算。基于无控飞行模型和仿真结果分析了无人机配载弹射式导弹发射特性,在导弹初始飞行段对机弹分离安全性和导弹姿态控制要求进行了研究。对导弹不同静稳定度下的运动特性对比分析,分别给出了满足各种安全和控制要求的导弹静稳定度范围。进一步综合所有安全和姿态控制要求,得到了满足所有要求的最佳静稳定度。经过一个实例的仿真研究,结果表明建立的模型与所用到的方法是合理有效的。     

埋入式抗滑桩支护边坡稳定性分析

为研究埋入式抗滑桩在滑坡治理中的适用性,总结前人经验并经大量现场调查研究,提出埋入式抗滑桩支护的3种失效模式,即桩后滑体整体失稳、桩顶滑体越顶失稳和桩前滑体滑移失稳;并从失效模式入手,简化埋入式抗滑桩支护边坡稳定性分析模型。结合定点剪出的破坏假定,用传递系数法分别验算桩周3部分土体即桩后土体、桩顶土体和桩前土体的稳定性。最后在埋入式抗滑桩支护边坡稳定性分析模型的基础上,围绕滑体几何形态、滑面倾角、滑带及滑体力学性质等关键因素,对埋入式抗滑桩的适用条件进行探讨。研究表明:埋入式抗滑桩置于平缓段有利于其阻隔作用的发挥,保证桩前滑体的稳定性;置于滑体强度大于滑带强度的滑坡,有利于利用滑体较高的土工参数;置于坡面平缓的滑坡,有利于桩顶滑体的稳定。     

北斗系统星载原子钟周期性波动的频谱分析校正方法

在建立卫星导航系统星座自主守时时间基准时,必须消除星载原子钟钟差数据中包含的周期性波动,以免将其引入系统时间。针对这一问题,基于国际卫星导航服务组织(International GNSS Service, IGS)提供的北斗系统星载原子钟钟差产品,提出了一种基于频谱分析的星载原子钟周期性波动校正方法。通过比较校正前后钟差数据的频率稳定度性能差异,确认该方法能够消除由环境因素引起的钟差数据周期性波动。北斗系统各类卫星星载原子钟的性能在校正后都得到了提升。地球同步轨道卫星星载原子钟的万秒频率稳定度提升50%左右,中轨道地球卫星星载原子钟的万秒频率稳定度提升23%左右,倾斜地球同步轨道卫星星载原子钟的万秒频率稳定度提升15%左右。经过校正,北斗二号和北斗三号系统中的星载原子钟普遍达到了地面站铯钟的频率稳定度性能,为完全基于星载原子钟的星座自主守时提供了基础。     

Acrimony,asymmetry, and the Sino-Indian nuclear relationship

ABSTRACT

While most contemporary analyses of South Asian nuclear dynamics acknowledge the presence of a strategic triangle between the region’s three nuclear players, the primary focus usually remains on the rivalry between India and Pakistan. Discussions of Sino-Indian relations remain limited. This is likely attributed to the stability in the two countries’ relations, yet it is worth asking why this stability exists and whether it is likely to continue in the future. Although China and India have an acrimonious relationship, their asymmetric nuclear capabilities and threat perceptions mitigate the danger of a traditional security dilemma. India may perceive China’s nuclear aggrandizement to be a security threat, but the same is not true of China, which has a vastly superior nuclear force and is largely shaping its nuclear-force structure in response to the threat it perceives from the United States. This dynamic makes a serious conventional or nuclear conflict highly unlikely.     

Chinese views of the nuclear endgame in North Korea

ABSTRACT

This 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.