Thermal behavior of an isolator with mode transition inducing back-pressure of a dual-mode scramjet

Combustion mode transition is a valuable and challenging research area in dual-mode scramjet engines. The thermal behavior of an isolator with mode transition inducing back-pressure is investigated by direct-connect dual-mode scramjet experiments and theoretical analysis. Combustion experiments are conducted under the incoming airflow conditions of total temperature 1270 K and Mach 2. A small increment of the fuel equivalence ratio is scheduled to trigger mode transition. Correspondingly, the variation of the coolant flow rate is very small. Based on the mea-sured wall pressures, the heat-transfer model can quantify the thermal state variation of the engine with active cooling. Compared with the combustor, mode transition has a greater effect on the iso-lator thermal behavior, and it significantly changes the isolator heat-flux and wall temperature. To further study the isolator thermal behavior from flight Mach 4 to Mach 7, a theoretical analysis is carried out. Around the critical point of combustion mode transition, sudden changes of the isola-tor flowfield and thermal state are discussed.     

从消费心理视角分析生活方式营销的价值

从消费者视角分析生活方式营销为产品和服务带来的附加值，对企业制定行之有效的生活方式营销模式提供有价值的参考。     

Use of reduce gravity conditions for the measurements of forces acting against the displacement of liquids inside containers

A setup called Controlled Rotation of Liquids (CROL) has been developed and used to investigate rotational behavior of liquids interacting with solids under reduced gravity conditions. The CROL setup allows us to evaluate the acceleration needed to overcome the interfacial forces that hinder liquid displacement inside different size containers. The well known Wilhelmy equation is used to explain the experimental results. Comparison between experimental results and theoretical predictions are presented and discussed.     

地方政府经济行为与制度创新

国有资本营运主体是国有企业，国有企业营运主体是企业家，由于地方政府在国民经济运行中所处的特殊地位，决定其经济行为对我国国有资本营运过程起举足轻重的作用，所以，制度创新与规范地方政府经济行为，也就成为现阶段改善国有资本驼绩效的战略选择。     

Experimental investigation of surface roughness effects on flow behavior and heat transfer characteristics for circular microchannels

This paper experimentally investigates the effect of surface roughness on flow and heat transfer characteristics in circular microchannels. All test pieces include 44 identical, parallel circu-lar microchannels with diameters of 0.4 mm and 10 mm in length. The surface roughness of the microchannels is Ra=0.86, 0.92, 1.02 lm, and the Reynolds number ranges from 150 to 2800. Results show that the surface roughness of the circular microchannels has remarkable effects on the performance of flow behavior and heat transfer. It is found that the Poiseuille and Nusselt num-bers are higher when the relative surface roughness is larger. For flow behavior, the friction factor increases consistently with the increasing Reynolds number, and it is larger than the constant the-oretical value for macrochannels. The Reynolds number for the transition from laminar to turbu-lent flow is about 1500, which is lower than the value for macrochannels. For the heat transfer property, Nusselt number also increases with increasing Reynolds number, and larger roughness contributes to higher Nusselt number.     

基于OODA过程的岛礁防空CGF模型

计算机兵力生成是军用仿真中的重要支撑技术。岛礁防空兵力生成是岛礁防空作战显示系统的关键部分。文章基于人类对外部事物认知、反应的OODA过程建立岛礁防空CGF行为模型,包括目标探测、威胁判断、火力分配及毁伤评估4个部分,在此基础上实现岛礁防空作战显示系统。     

Constitutive behavior and microstructural evolution in hot deformed 2297 Al-Li alloy

The microstructural evolution mechanism and constitutive behavior of 2297 Al-Li alloy were studied via thermal compression test with the constant strain rates of 0.001–1 s⁻¹ and the deformation temperatures ranging from 623 to 773 K. To verify the predictable ability of diverse constitutive models under different stress states, the hot compression experiments with stress triaxiality varying from −0.33 to 0.46 were conducted. The microstructures of the deformed specimens under diverse deformation conditions are probed to reveal the mechanism of hot deformation behavior. The experimental results indicate that the work-hardening and dynamic softening are competitive during the hot compression process, and the dynamic softening is more obvious under low deformation temperature and high strain rate. The microstructural analysis manifests that the dynamic recovery gets predominant at high deformation temperature to produce fine grains. Meanwhile, the dynamic recrystallization becomes more dominant as the strain rate decreases, which is sensitive to the stress triaxiality. In addition, both the modified Johnson-Cook model and strain-compensated Arrhenius-type function are suitable for describing the flow behavior of 2297 alloy, while the latter reveals a more accurate prediction. However, the predictability of the two kinds of models is worsened with the transformation of stress triaxiality, and the validity of the Arrhenius-type model is restricted by high stress triaxiality.     

基于Logit模型的航班延误后乘客行为选择研究

目前中国航班延误现象较为普遍，航班延误后乘客行为和心理研究是航班延误现象研究的重要组成部分。现有研究相对较少，对于航班延误后乘客行为选择的研究尚未出现。为了研究乘客在航班延误后行为选择的影响因素，采用调查法，并结合Logit模型，发现自费与否、出行人数、对航空公司品牌看重程度和航班延误告知与否4个因素对于航班延误后乘客行为选择的影响最为显著。同时，结合分析结果，为航空公司制定经营战略提供参考。     

虚拟维修仿真系统的设计与实现

为解决当前虚拟维修平台在处理维修任务时存在的不足，提出了虚拟维修仿真系统结构框架。将系统结构设计成主要由维修场景构建、维修任务和动作分解及维修性分析评价数据输出三个功能模块组成。基于Jack软件平台完成了系统开发。以某装备维修任务典型工况为例，对系统进行实例验证。结果表明：该系统能有效地加快维修过程的创建，改善了人机界面的交互功能，提高了虚拟维修仿真系统的智能化程度，基本满足了维修仿真的需求，具有可行性与实用性。     

我国社区管理的模式及其优化

一个社区管理中的重大问题,即社区管理中政府行为、市场机制与自组织治理的各自定位及其相互关系问题,还没有引起人们的足够重视。这一重大问题不解决,就无法实现社区管理模式的优化。