未来能量互联的关键设备——固态变压器

固态变压器作为能源互联网中实现能量转换和控制的关键设备,有很多方面需要进行深入研究,文章结合固态变压器的自身特点,对其主要发展的核心技术,包括基于SiC新型宽禁带材料的研制、基于SiC的固态功率器件和固态变压器设计与实现、固态变压器的先进控制策略研究等进行了详细阐述。     

高超声速飞行器中若干气动难题的实验研究

回顾了近几年本研究团队在高超声速飞行器若干气动难题方面的实验研究进展。在边界层转捩方面,测量了边界层转捩现象,研究了攻角效应对圆锥边界层转捩的影响,获得了边界层转捩的脉动特性以其对飞行器表面热流和摩阻的影响。在激波-边界层干扰方面,分析了突起物形状变化对流动特性的影响,研究了复杂外形的流动特性。     

多态的大功率可控硅开关功率放大器的仿真

为了满足远距离海底探测对发射信号大功率的需求,选用了一种大功率可控硅开关功率放大器。在临界换流、自然换流和强迫换流3种工作状态下,分析了该功率放大器的工作原理,并建立了等效电路模型。运用Or CAD仿真了临界换流状态时的等效电路模型;在自然换流状态和强迫换流状态下,为获得功放电流值和负载电流值,对其等效电路模型分别建立了非线性数学模型,并通过Matlab和VC++采用四阶Runge-Kutta法对非线性数学模型进行求解。以上方法能够求得该功率放大器电路在任意时刻、任意点处的电流电压值,能较客观、真实地反映电路的工作状况,对工程应用具有一定的参考价值。     

Political transition to democracy

This paper argues that the crisis of electoral democracy in Zimbabwe and Cote d'Ivoire is a result of underlying structural and institutional deficiencies within national and regional multinational institutions. It assesses the extent to which they have been ‘enablers’ or ‘spoilers’ of electoral-based transitions to democracy. Yet it avoids generalisations of the security sector's involvement in political transitions. In terms of structure, the paper is divided into four sections. Section one will briefly discuss the theoretical perspectives of the election-democracy trajectory. It argues that although elections are a major variable for democracy, unless the ‘ecology of elections’ is conducive, elections may not be an instrument of transition to democracy. The second section analyses the militarisation of politics and the role of the security sector in aiding or stalling democratisation. Section three will assess the role of regional organisations such as the Southern African Development Community, Economic Community of West African States and the African Union in electoral-based political transitions in Africa. Lastly, the paper will discuss how the security sector and multinational African institutions can aid political transitions to democracy in troubled African countries.     

因素状态值为模糊数的变权综合决策方法

对因素权重为实数、因素状态值为模糊数的多因素不确定性决策问题,由实数型状态变权向量导出模糊数状态变权向量,得出模糊数变权公式,建立模糊数变权综合决策模型,最后给出一个应用模糊数变权综合决策模型的实例.     

武器装备人机界面操控性评价方法研究

针对武器装备人机界面操控性难以有效评价的问题,提出人机界面操控易用性的评价指标,利用信息距离对易用性进行分析,并建立武器装备人机界面易用性的评估模型,并通过实例进行武器装备易用性评价分析,为武器装备人机界面操控性设计优化及检验标准的制定提供了借鉴。     

The effect of foreign state support to UNITA during the Angolan War (1975–1991)

ABSTRACT

State support for foreign rebel groups has become more salient, yet it remains unclear how this affects armed conflict. This paper therefore analyses the effect of foreign government assistance and does so in the typical case of the Angolan War (1975–1991). It argues that South African and United States support greatly helped the National Union for the Total Independence of Angola (UNITA) wage a large and sustained insurgency campaign but was ultimately insufficient to overthrow the People’s Movement for the Liberation of Angola (MPLA) government because it enabled the incumbent government to obtain similar foreign assistance and because the level of aid awarded to UNITA fluctuated strongly, preventing it from engaging in meaningful long-term planning.     

从治国理政的高度大力推进生态文明建设

建设生态文明是我们党对人类社会发展规律和社会主义现代化建设规律认识的新发展,也体现了我们党执政理念的进一步完善。因此必须从治国理政的战略高度认识并推进生态文明建设。建设生态文明是破解我国发展中种种难题的现实途径、全面建成小康社会的迫切要求、实现中华民族永续发展的客观要求,必须从树立生态文明理念、转变经济发展方式、建立完善生态文明制度机制着手。同时,生态文明建设也是军队建设科学发展的题中应有之义。     

一种用于雷达网目标状态融合的算法

针对目前雷达情报自动化系统中雷达网目标状态融合存在航迹不连续、情报信息利用率低等问题,综合运用了神经网络和军事运筹学理论和方法,给出了一种用于雷达网目标状态融合的算法.结果表明,利用本方法使融合后的目标轨迹与目标真实运动轨迹非常接近,有效地提高了雷达情报的综合质量.     

动力伞8自由度动力学建模与仿真

现有文献中的翼伞建模方法多数是针对不带动力情况下的翼伞建模,不能适应动力翼伞的飞行控制。为了实现动力伞的有效控制,首先要建立合理的动力学模型。假设翼伞承载物和软翼之间具有2个自由度,分别建立软翼和承载物体坐标系下的作用力和力矩的平衡方程,通过体坐标系转换和消除翼伞内部状态量,得到有利于实现翼伞控制的8自由度非线性状态方程。仿真表明模型的飞行曲线与飞行实验的结果相一致,验证了模型的有效性。