改性C/C复合材料快速制备与抗烧蚀性能考核

采用液相浸渍法结合反应熔渗法快速制备改性C/C复合材料,研究其微观组织及在氧乙炔焰和高频等离子体风洞环境中的烧蚀行为。结果表明:改性C/C复合材料主要含有Hf C,Zr C,Ta C等高熔点陶瓷改性相,其密度为3.83 g/cm3,开孔率仅为4.71%。氧乙炔焰烧蚀360 s后,改性C/C复合材料表面形成一层主要由Hf O2,Zr O2,Ta2O5组成的致密氧化物层,材料的线烧蚀率为0.005 18 mm/s。使用高频等离子体风洞考核改性C/C复合材料球头模型,在热流量3.5 MW/m2、驻点温度2293℃的条件下考核180 s后,模型表面生成致密光滑的氧化物保护层,与基体结合牢固,模型形状及尺寸无明显改变,去掉氧化物后测得其线烧蚀率为0.001 72 mm/s。     

整体缝合夹芯结构复合材料力学性能

所设计的新型整体缝合泡沫夹芯复合材料结构,能够避免一般斜缝方式引起纤维交叉损坏的弊端。采用真空导入模塑工艺制备整体缝合泡沫夹芯结构复合材料,研究缝合结构、缝合方式以及缝合纱线用量对整体缝合泡沫夹芯复合材料平压力学性能和弯曲性能的影响。结果表明,新型缝合结构在保证平压力学性能的同时,相比于垂直缝合结构弯曲破坏载荷提高了94.4%;穿透缝合方式能够显著提高试样的平压强度和弯曲破坏载荷;随着缝合纱线用量的增加,整体缝合泡沫夹芯复合材料的压缩和弯曲性能显著提高。     

Lot sizing with learning and forgetting in setups: Analytical results and insights

This article considers the dynamic lot sizing problem when there is learning and forgetting in setups. Learning in setups takes place with repetition when additional setups are made and forgetting takes place when there is a break between two successive setups. We allow the amount forgotten over a break to depend both on the length of the break and the amount of learning at the beginning of the break. The learning and forgetting functions we use are realistic. We present several analytical results and use these in developing computationally efficient algorithms for solving the problem. Some decision/forecast horizon results are also developed, and finally we present managerial insights based on our computational results. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 93–108, 2016     

倾听与发现：兵团民办幼儿园发展的困境与出路

兵团民办幼儿园作为兵团幼儿教育发展的重要群体,在发展的同时面临着诸多困境。研究结果显示,兵团民办幼儿园的发展面临严重的困境：经费不足;教师队伍不稳定;家园联系合作深度不够。研究认为促进兵团民办幼儿园发展的对策：一是提高政策监管力度,建立良好的政策和经济环境;二是完善民办幼儿园教师的工资和福利待遇及培训制度,提升民办幼儿园教师的质量;三是加强家园合作,引导家长形成正确的幼儿园课程观。     

公共服务均等化视域下新疆南疆教育扶持政策研究

新疆南疆落后的经济社会造成教育发展缓慢、水平低下,大力发展南疆教育具有极端重要性,近年来国家对南疆教育实施了一系列扶持政策并且取得了良好的效果。本文运用公共服务均等化的分析框架,对南疆教育扶持政策所体现出的价值取向、政府职能转变,以及教育公共服务均等化的物质基础和逻辑起点等四个方面进行了理性分析,并从大力发展国民经济、优化资源配置机制和完善转移支付制度三个角度提出优化南疆教育均等化的建议。     

一种新的复合导引头多源异步信息融合精确拦截算法

针对单一制导体制难以满足现代战场作战需求,而多传感器数据更新率不同步的问题,建立一种新的微惯导/毫米波/红外复合制导体制,研究了该体制下多传感器异步信息融合的时间同步和空间配准问题;提出一种自适应Unscented卡尔曼滤波算法,该算法采用预测残差构造状态模型误差统计量,通过自适应因子调整状态模型信息对状态参数估值的贡献,有效控制状态模型噪声异常对状态参数估值的影响。将提出的算法应用到微惯导/毫米波/红外复合制导系统中进行仿真验证,结果表明,提出的自适应Unscented卡尔曼滤波算法的解算精度高于标准扩展卡尔曼滤波和Unscented卡尔曼滤波算法,能有效提高导弹的制导的解算精度。     

分布式遗传模拟退火算法的火力打击目标分配优化

根据火力打击规则,建立了多目标函数的目标分配模型,提出了分布式遗传模拟退火算法对模型进行求解。分布式遗传模拟退火算法基于经典遗传算法进行改进:将单目标串行搜索方式变成多目标分布式搜索方式,适用于多目标寻优问题求解;采用保留最优个体和轮盘赌相结合的方式进行个体选择,在交叉算子中引入模拟退火算法,使用自适应变异概率,较好地保持算法广度和深度搜索平衡。最后,通过仿真实验验证了算法的有效性和可靠性。     

复合导引头多源异步信息融合精确拦截算法

针对单一制导体制难以满足现代战场作战需求且多传感器数据更新率不同步的问题,建立一种新的微惯导/毫米波/红外复合制导体制,研究了该体制下多传感器异步信息融合的时间同步和空间配准问题;提出一种自适应无迹卡尔曼滤波算法,该算法采用预测残差构造状态模型误差统计量,通过自适应因子调整状态模型信息对状态参数估值的贡献,有效控制状态模型噪声异常对状态参数估值的影响。将提出的算法应用到微惯导/毫米波/红外复合制导系统中进行仿真验证,结果表明,提出的自适应无迹卡尔曼滤波算法的解算精度高于标准扩展卡尔曼滤波和无迹卡尔曼滤波算法,能有效提高导弹的制导的解算精度。     

India–Africa defence cooperation against the backdrop of the ‘Make in India’ initiative

Although India is a major importer of defence equipment, it has also been manufacturing defence equipment for some of its needs. The Government of India’s ambitious ‘Make in India’ initiative for the defence sector aims to achieve self reliance in defence equipment production. This essay explores the opportunities for bilateral arms trade between India and Africa, as a new facet of India-Africa defence cooperation. It covers India’s arms export policy, policy reforms in India’s defence sector, and the opportunities for Indian and African defence markets.     

Potential impact of recharging plug‐in hybrid electric vehicles on locational marginal prices

Plug‐in hybrid electric vehicles (PHEVs), upon market penetration, will create additional recharging loads to the electric power systems. This article considers different recharging scenarios and uses game theoretic models to study the potential impact of the recharging loads on locational marginal prices (wholesale electricity prices). Computational results from a Pennsylvania‐New Jersey‐Maryland Interconnection case study show that, under the existing recharging infrastructures, even a small magnitude of load increase caused by PHEV recharging could have a significant undesirable impact on locational marginal prices. The impact could be mitigated to a varying extent by the availability of possible future recharging infrastructures, including realtime pricing recharging meters, battery stations, or vehicle‐to‐grid technology.© 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010