土质隧洞围岩稳定性分析与设计计算方法探讨

论述了以洞周位移量与围岩塑性区大小作为围岩稳定性经验判据的不足，依靠模型试验与力学计算，分析了隧洞破坏机理与形式。由此提出将基于有限元强度折减法求出的围岩安全系数作为稳定分析判据，这种判据有严格的力学依据，有统一的标准，而且不受其他因素的影响。研究了隧洞围岩安全系数（剪切安全系数、拉裂安全系数）与衬砌安全系数的算法以及隧洞设计计算方法。最后以黄土洞室为例，给出了土体隧洞设计计算新方法，并对土体隧洞今后的研究方向提出了几点展望。     

潜艇水下回转运动稳定性分析

水下回转运动是潜艇常用的运动形式之一,属于潜艇转向运动的重要研究内容。回转运动过程中,潜艇受力复杂,容易出现分岔等非线性现象,潜艇运动稳定性变差。运用同伦延拓法、分岔理论和李雅普诺夫运动稳定性理论分析了潜艇水下回转运动稳定性,并通过数值仿真试验验证了分析结果的正确性和分析方法的有效性,为潜艇运动稳定性的研究提供了思路。     

Missile defense and strategic stability: Terminal High Altitude Area Defense (THAAD) in South Korea

South Korea is threatened by its troubled relationship with North Korea. North Korea possesses a large cache of missiles as well as chemical and biological weapons, and the future potential to mount nuclear weapons on its missiles. The United States is also challenged because of its defense commitments to Seoul. As a countermeasure, the United States and South Korea decided to deploy Terminal High Altitude Area Defense (THAAD) missile defenses in South Korea. However, China has objected. Chinese scholars believe the THAAD radar would be able to track Chinese inter-continental ballistic missiles, thereby weakening their deterrent. A technical analysis does not support this assertion. However, it is vital for South Korea, given its proximity and economic interdependence, to reassure China. South Korea should highlight that THAAD will be deployed by the United States Forces Korea and is not a commitment by Seoul to become part of U.S.-led missile defenses in the Asia-Pacific.     

MEO非共振轨道导航星座摄动补偿控制

针对我国新一代全球导航星座长期构型维持控制问题,提出了MEO星座构型状态描述方法,分析了主要摄动力和轨道参数偏差作用下的星座构型演化规律,结合实测数据对稳定性规律进行了验证;研究了参数偏置摄动补偿控制原理,提出了一种改进的解耦控制方案,分析了星座部署时间对摄动补偿控制量的影响规律,得到了一些有益的关键性结论,为我国全球导航系统的星座构型设计和运控策略制定奠定了基础。     

基于脉冲控制的末修弹飞行稳定性研究

脉冲力的瞬间作用会引起攻角和侧滑角的急剧变化,对末修弹飞行稳定性产生较大的影响.以线性化运动微分方程组为数学解析手段,对末修弹脉冲作用稳定性进行深入分析研究.数值仿真表明,采用小扰动法分析弹丸脉冲控制弹丸飞行稳定性是可行的.     

一类具有时滞和Gompertz增长率的捕食系统的稳定性与Hopf分支

研究一类具有时滞和Gompertz增长率的捕食系统,通过分析系统的特征方程,得到正平衡点的局部稳定性和系统出现Hopf分支的条件,并利用中心流形定理和规范型理论,得到确定Hopf分支方向和分支周期解稳定性的计算公式．     

一类具有时滞的生态一流行病系统的稳定性和Hopf分支

讨论一类食饵染病的时滞捕食一被捕食者模型,通过分析特征方程,得到正平衡点局部稳定和Hopf分支存在的条件．同时,应用中一tl,流形定理和规范型理论研究正平衡点处Hopf分支方向和分支周期解的稳定性．最后,通过数值模拟对理论结果进行了说明．     

South Asia's Missile Expansion

ABSTRACT

Over the past decade, contrary to declarations that they are pursuing “minimum” deterrence, India and Pakistan have considerably expanded their missile forces. India has developed eleven types of missiles while Pakistan has fielded nine. These missile forces have a mixed impact on deterrence stability. Both states' medium-range missiles strengthen their countervalue deterrent capabilities against the other, though India's China-specific missiles still have limitations. India's and Pakistan's short-range missiles and first-generation naval systems raise concerns about nuclear ambiguity, command and control, and escalation across the nuclear threshold, ultimately undermining deterrence stability on the subcontinent.     

REGIONAL PERSPECTIVES ON LOW NUCLEAR NUMBERS

President Barack Obama has outlined a course toward lower numbers of US nuclear weapons. Much attention has been paid to the US-Russian context, where deterrence is believed to be basically stable and conditions ripe for gradually reducing arsenals on both sides. But considerably less attention has been paid to the possible implications of lower nuclear numbers on other regions of the world and the reactions of both adversaries and US allies. If nuclear reductions are to be stabilizing and beneficial to security, reassurance and strengthened nonproliferation efforts in various regions need to accompany nuclear cuts. But the specific problems and remedies across regions vary. This article summarizes the results of a multi-author study. It concludes that regions with US allies and formal extended deterrence pledges may pose more vexing problems than those areas of the world without such close allies or commitments.     

NUCLEAR STABILITY AT LOW NUMBERS

Chinese writings on the workings of nuclear stability, deterrence, and coercion are thin and politicized. Nevertheless, it is possible to glean, from direct and inferential evidence, rather pessimistic conclusions regarding Chinese views of nuclear stability at low numbers. While China has been living with low numbers in its own arsenal for decades, today it views missile defense and advanced conventional weapons as the primary threat to nuclear stability. More generally, China views nuclear stability as wedded to political amity. Because none of these would be directly addressed through further US and Russian arsenal reductions, China is unlikely to view such reductions as particularly stabilizing. While there is little in Chinese writing to suggest lower US and Russian numbers would encourage a “race to parity,” there are grounds to worry about China becoming more assertive as it gains confidence in Beijing's own increasingly secure second-strike forces.