Brazilian National Defence Policy: foreign policy,national security,economic growth,and technological innovation

ABSTRACT

With the world’s ninth largest economy and comprising nearly 60% of South America’s GDP, 47% of its territory, and 49% of its population, Brazil has become a regional power and an important actor in world affairs over recent decades. This scenario has led the government to re-evaluate its role in the world order, resulting in the enactment of the National Defence Policy, whose objective was to consolidate the country as a regional power while at the same time addressing national security issues, promoting economic development through a series of defence programmes, restructuring the defence industrial base, fostering innovation through technology and knowledge transfer to Brazil, and indigenous research and development. However, the policy’s implementation suffers from several challenges discussed in this article, which may test the capability and competence of Brazilian policymakers, military, industrialists, and other individuals and organisations involved in its implementation.     

多阶段含延缓纠正的可靠性增长序化建模分析

多阶段含延缓纠正的可靠性增长试验,其各个阶段内的试验数据分别服从参数不同的Weibull过程.针对现场样本少、传统的可靠性评估方法实施困难的问题,首先在获得各阶段形状参数的基础上,对各个阶段截尾时刻的失效强度建立顺序约束关系.然后,运用Bayes方法融合先验信息,获得最末阶段截尾时刻的失效强度的期望与置信上限.该结果融合了历史阶段的样本信息,优于仅利用单个阶段样本的分析结果,适用于多阶段可靠性增长试验的综合评估.     

非均匀复合材料中裂纹扩展过程的数值模拟

应用有限单元法和最大正应力准则,引入楔形界面过渡层模型,求解相应的特征函数,准确地确定界面裂纹第一步开裂角,模拟了裂纹在非均匀复合材料中的扩展过程。结果表明:裂纹扩展初期呈波浪式前进,并最终沿着与最大正应力垂直的方向前进。这对此类结构的防断控制具有指导意义。     

火箭发动机可靠性增长评估的Bayes方法

针对火箭发动机分阶段试验,每阶段试验后对发动机出现的故障分析、归零的情况,提出等效试验数据的概念,结合Bayes方法对系统的可靠性增长试验进行评估,并在此基础上给出可靠度的增长分析,最后给出实例进行说明。     

奇异积分方程在裂纹板条动态断裂分析中的应用(I)

利用积分变换方法,将含Ｇｒｉｆｉｔｈ裂纹的无限长板条问题转化为Ｌａｐｌａｃｅ变换域中一Ｃａｕｃｈｙ型奇异积分方程。通过求解奇异积分方程和对裂纹尖端场的渐近分析,获得了Ｌａｐｌａｃｅ变换域中的动态应力强度因子。     

矩形波导结构潘尼管工作特性的分析

本文导出了一般TE_(no)模矩形波导结构潘尼管的色散方程,对潘尼管作了更明确的解释,并详细计算了TE_(20)模潘尼管的色散方程,得到其基波和第三次谐波同步谐振的色散曲线。该曲线表明,潘尼管在基波谐振上有1.5%的增长率,而在第三次谐波上有0.8%的平均增长率。此外,用非线性理论分析基波和第三次谐波同步谐振时的工作情况,给出了电子饱和时的电子分布图。在常直流磁场下优化结果表明,潘尼管在其次谐振时有51%的高效率和QP_w=9949.9MW 的输出功率,而在第三次谐振时有11%的效率和QP_w=1741.8MW 的输出功率。     

双材料界面裂纹的加料有限元方法

为解决求解双材料界面裂纹应力强度因子等断裂参量的困难,在常规单元位移模式中引入界面裂纹尖端位移场,构建加料界面裂纹单元和过渡单元的位移模式,推出了加料有限元方程。采用不同的加料单元和过渡单元配置方案,建立了方形板中心界面裂纹和矩形板单边斜界面裂纹的加料有限元模型,求解有限元方程直接得到应力强度因子,与解析解的结果对比,表明该方法具有较高的精度,可方便地推广应用于界面裂纹的计算分析中。     

锥形液膜的Kelvin-Helmholtz扰动波

为进行锥形液膜雾化过程分析,研究锥形液膜的Kelvin-Helmholtz稳定性问题,应用小扰动假设,建立了锥形液膜数学模型、轴对称扰动运动的控制方程和边界条件,采用分离变量法求解线性偏微分扰动方程组,经过严格的数学推导,得到了锥形液膜内外表面扰动波增长速率特征方程.当液膜锥角为零时,与环形液膜扰动波特征方程一致;当液膜锥角和液膜内径为零时,与圆射流扰动波特征方程一致,表明导出的锥形液膜扰波动方程是合理的.     

Book reviews

The Political Economy of Military Spending in the United States, Alex Mintz (ed), London and New York: Routledge, 1992, pp x, 334; ISBN 0–415–07595–5

Penser La Guerre, Penser L'Economie, Christian Schmidt, (Paris: Odile Jacob, 1991), 350p.

Military Production and Innovation in Spain, Jordi Molas‐Gallart, Chur (CH): Harwood Academic Publishers, 1992, pp. vii, 212; ISBN 3–7186–5280–3     

A note on the causal relationship between defence spending and growth in Greece: 1955–93

The causal relationship between economic growth and defence spending has attracted considerable attention and has been the subject of many empirical studies. This paper investigates the existence of a causal link between military expenditure and economic growth in the case of Greece for the period 1955–93. By European Union standards, Greece allocates substantial human and material resources to defence. At the same time, Greece is the poorest European Union member facing chronic economic problems. Using the concept of Granger‐causality, the findings reported herein suggest that neither variable Granger‐causes the other disclosing thereof the absence of any causal ordering between them.