All Together Now? Questioning WMDs as a Useful Analytical Unit for Understanding Chemical and Biological Weapons Proliferation

ABSTRACT

The 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.”     

THE PROLIFERATION SECURITY INITIATIVE

The Asia-Pacific is emerging as a critical region in the fight against the proliferation of weapons of mass destruction. The Proliferation Security Initiative (PSI) is an aggressive global strategy designed to interdict the transport of these weapons and associated technologies. However, some observers have suggested that the Asia-Pacific has given the PSI a less than enthusiastic reception. The authors posit a more sanguine view. They caution against taking such a holistic approach to the region. Asia does not speak with one voice when it comes to security, and opposition to the PSI is not as widespread nor deep-rooted as may have been anticipated. In addition, the PSI's informal structure encourages flexibility, enabling states to participate in certain activities while eschewing others that may be technically or politically untenable.     

变质心再入飞行器自抗扰控制器设计(英文)

再入飞行器采用变质心控制不但可以保持较好的气动外形,还町以增大机动能力,但变质心控制较强的非线性和耦合性大大增加了控制系统设计难度,使控制器设计和实施的代价较高。针对这一问题,基于自抗扰控制技术,设计了变质心再入飞行器双通道解耦控制器。通过构造连续光滑扩张状态观测器,不加区分飞行器的各类干扰与耦合,对其统一进行估计:利用非线性状态反馈控制律,并自适应调节控制参数对其进行补偿,实现对飞行器姿态的解耦控制。仿真结果表明:该方法大大降低了对系统模型精度的要求与控制器设计实施代价,对变质心再入飞行器非线性、耦合性以及参数摄动具有较强的鲁棒性。     

带有大质量刚体圆锥壳的自由振动分析

本文针对壳体带有大质量刚体的特点,用有限元离散方法,导出了在不同周向波数下壳元节圆位移与刚体质心位移及转角之间的关系式,并将结果与实际运动进行对比分析,论证了结论的正确性。为带有大质量刚体的壳体结构的动力分析提供了理论依据。     

发动机运动件质量对燃油消耗率影响的分析

发展了一个发动机运动件质量对燃油消耗率影响的分析公式,进行了实例计算。在发动机设计阶段和发动机实际使用中,可以应用这个公式,估计运动件质量变化所引起的比油耗的相对变化。     

一种可移动式科氏流量计实验平台设计与实现

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An experiment evaluating how the tiny mass eccentricities in spin-stabilized projectiles affect the position of impact points

This study investigates and quantifies some possible sources affecting the position of impact points of small caliber spin-stabilized projectiles (such as 12.7 mm bullets). A comparative experiment utilizing the control variable method was designed to figure out the influence of tiny eccentric centroids on the projectiles. The study critically analyzes data obtained from characteristic parameter measurements and precision trials. It also combines Sobol's algorithm with an artificial intelligence algorithm—Adaptive Neuro-Fuzzy Inference Systems (ANFIS)—in order to conduct global sensitivity analysis and determine which parameters were most influential. The results indicate that the impact points of projectiles with an entry angle of 0° deflected to the left to that of projectiles with an entry angle of 90°. The difference of the mean coordinates of impact points was about 12.61 cm at a target range of 200 m. Variance analysis indicated that the entry angle — i.e. the initial position of mass eccentricity — had a notable influence. After global sensitivity analysis, the significance of the effect of mass eccentricity was confirmed again and the most influential factors were determined to be the axial moment and transverse moment of inertia (Izz Iyy), the mass of a projectile (m), the distance between nose and center of mass along the symmetry axis for a projectile (Lm), and the eccentric distance of the centroid (Lr). The results imply that the control scheme by means of modifying mass center (moving mass or mass eccentricity) is promising for designing small-caliber spin-stabilized projectiles.     

群死群伤恶性火灾的特点及预防

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基于Simulink的质点外弹道模型仿真

介绍了基于Simulink的质点外道模型的设计与仿真方法。首先给出了地面直角坐标系下的弹丸质心运动方程组,然后介绍如何采用Simulink建立系统的仿真模型并进行仿真计算。仿真方法具有模型设计过程简单、修改容易和结果直观等特点,可以应用到刚体弹道、火箭弹道及控制弹道等模型的仿真。     

二维抛板极限速度的相似性与古尼公式的采用

本文分析影响被炸药驱动下抛板极限速度的重要因素,讨论了一些经验公式的适用范围;提出了根据二维抛板的数值计算得到的两个重要规律:①在炸药与抛板的质量比相同的情况下,抛板的极限速度之间具有一定的相似关系;②修正的古尼公式可用来计算二维抛板的极限速度。