径向三腔渡越时间振荡器数值模拟

基于渡越辐射机理结合径向结构的低阻抗特性,提出了一种新型的低阻抗高功率微波器件——径向三腔渡越时间振荡器,它由3个等间距的边耦合同轴腔组成,径向运动电子束与谐振腔中的角向均匀模式场相互作用。采用PIC粒子模拟程序进行了模拟研究。在电子束能量450 keV、束流60 kA且无外加引导磁场的条件下,当结构参数网长为4.8 cm,腔间距为1.4 cm,电子发射面为0.8 cm,内径为8 cm时,获得了平均功率7.4 GW,频率4.1 GHz的微波输出,效率达27.4%,阻抗7.5 Ω。通过粒子模拟给出了束波互作用效率随电子束电压、电流以及谐振腔间距的变化曲线,电子束电压对输出微波频率的影响曲线以及不同谐振频率与最佳谐振腔间距的对应曲线,这些曲线表明该器件具有渡越时间效应的基本特征,属于渡越辐射器件,且具有对电子束质量要求不高的特点。     

X波段渡越管振荡器的粒子模拟和优化设计

提出了一种新型的渡越管谐振腔结构,通过全电磁2.5维相对论粒子模拟程序证实电子束可以与这种谐振腔结构发生互作用;基于该谐振腔结构,用全电磁2.5维相对论粒子模拟程序设计优化了可工作在X波段的渡越管振荡器,其输出功率大约1.7GW,束波转换效率约37%。     

Current Status and Development Trend of Natural Gas Industry in China

In China, the proven reserves of natural gas is 3.86 trillion cubic meters (tcm). This figure will quite possibly increase at a high speed in the future. At present, the annual production of natural gashas exceeded 34 billion cubic meters (bcm), which, likewise, will rise sharply. The pipeline constructionhas basically taken shape, which will be gradually perfected. And the gas consumption market is in thestartup stage, which will be rapidly expanded in the quite near future.     

Solving Planning and Design Problems in the Process Industry Using Mixed Integer and Global Optimization

This contribution gives an overview on the state-of-the-art and recent advances in mixed integer optimization to solve planning and design problems in the process industry. In some case studies specific aspects are stressed and the typical difficulties of real world problems are addressed. Mixed integer linear optimization is widely used to solve supply chain planning problems. Some of the complicating features such as origin tracing and shelf life constraints are discussed in more detail. If properly done the planning models can also be used to do product and customer portfolio analysis. We also stress the importance of multi-criteria optimization and correct modeling for optimization under uncertainty. Stochastic programming for continuous LP problems is now part of most optimization packages, and there is encouraging progress in the field of stochastic MILP and robust MILP. Process and network design problems often lead to nonconvex mixed integer nonlinear programming models. If the time to compute the solution is not bounded, there are already a commercial solvers available which can compute the global optima of such problems within hours. If time is more restricted, then tailored solution techniques are required.     

Continuous Markovian Model for Unexpected Shift in SPC

Various process models for discrete manufacturing systems (parts industry) can be treated as bounded discrete-space Markov chains, completely characterized by the original in-control state and a transition matrix for shifts to an out-of-control state. The present work extends these models by using a continuous-state Markov chain, incorporating non-random corrective actions. These actions are to be realized according to the statistical process control (SPC) technique and should substantially affect the model. The developed stochastic model yields Laplace distribution of a process mean. Real-data tests confirm its applicability for the parts industry and show that the distribution parameter is mainly controlled by the SPC sample size.     

考虑库存和市场占有率的纵向一体化

本文将传统的双重加价模型扩展到包含库存因素的上下游厂商均为垄断企业、下游厂商为寡头垄断企业而上游厂商为完全垄断企业以及上游厂商为寡头垄断企业而下游厂商为完全垄断企业的一体化模型，着重探讨了库存成本和市场占有率对纵向一体化的影响。研究结果表明，只有在库存成本较低时，传统的结论才得以维持；一体化始终导致消费者福利上升而不受市场占有率的影响，但一体化使厂商的总利润增加要在市场占有率较高时才能实现。     

复杂环境下银行业多指标风险评估方法及防控策略研究——基于中国省际面板数据的分析

在目前国内外复杂金融环境下,有效识别金融风险及其变化趋势有助于防范和化解金融危机,筑牢国家金融安全屏障。特别是在大数据金融蓬勃发展的背景下,应用数据信息监控金融风险的状况和趋势更具重要的现实意义。以下首先依托已有经验数据提出度量极大经验风险曲面和极小经验风险曲面的方法。其次,根据极大风险曲面提出计算决策单元综合风险指数的模型,以及相应的决策单元投影公式。同时,依据极小风险曲面估计决策单元风险降低的程度和策略。最后,应用这些方法分析了中国31个省区市2013~2017年银行业的风险状况,并提出了相应的改进策略。     

基于科学发展历史的教学设计层次分析

结合具体案例阐述了教学中应用科学史进行教学的5个层次：内容识记水平、兴趣激发水平、概念转变水平、科学方法水平和社会文化水平。对每一水平的教学目标、理论依据、实施要点和不足进行分析,在此基础上指出今后的发展方向。     

国防工业发展中的三方博弈分析

利用博弈论的方法对国防工业发展中已进入国防工业的企业群、待进入国防工业的企业群和政府的对策进行分析,并得出结论:政府首先要指导已进入国防工业的企业群合理定位;其次要考虑制定多大程度的保护政策来保护已进入国防工业企业的发展和利益;最后政府需要对军工企业的诉讼制定合理的支持标准,使已进入国防工业企业始终处于竞争环境良性发展.当然政府作出以上决策的主要依据是在保证本国安全的前提下使国防工业企业的利润实现最大化.     

基于突变理论的产业升级能力评价研究——以陕西装备制造业为例

在界定产业升级内涵的基础上,根据陕西装备制造业的发展现状及产业升级的客观要求,从产业升级的产出能力和投入能力两个维度构建了装备制造业产业升级能力评价指标体系,并运用突变模糊隶属度函数法对陕西装备制造业各下属产业升级能力进行了综合评价,结论表明:装备制造业所属的七个子行业的产业升级能力存在很大差距,其中金属制品业的产业升级能力最强,通用设备制造业、通信计算机及其他电子设备制造业、专用设备制造业次之,仪器仪表制造业、电气机械及器材制造业、交通运输设备制造业最差.进一步分析了产生这一结果的深层原因,在此基础上提出了陕西装备制造业产业升级的对策建议.