论 C3I 系统的建模

本文在对Ｃ~３Ｉ系统的建模问题进行深入讨论后,提出了一套用于Ｃ~３Ｉ系统建模的规范化建模方法,并由计算机实现了该方法,使得人们可以通过人机对话的形式进行建模。这一方法解决了目前战争系统尤其是Ｃ~３Ｉ系统的微分方程不易得到这个问题。文中给出了一个建模案例。     

苯乙炔与二苯丁二炔的共聚及共聚物的表征

本文以(Ph_3P)_2PdCl_2作催化剂,合成出聚二苯丁二炔和二苯丁二炔与苯乙炔共聚物。均聚物及共聚物产率都在90%以上,均聚物分子量为900,二苯丁二炔与苯乙炔最佳摩尔比为1/2(数均分子量为1205)。结构分析表明,均聚物及共聚物均具有反—反式结构。     

Impacts of logistics information on sales: Evidence from Alibaba

Facing fierce competition from rivals, sellers in online marketplaces are eager to improve their sales by delivering items faster and more reliably. Because logistics quality can be known only after a transaction, sellers must identify effective ways to communicate logistics information to consumers. Drawing on the accessibility-diagnosticity framework, we theorize that the sales impacts of logistics information depend on its relative diagnostic value. Using data on 1493 items with 505,785 consumer reviews from an online marketplace, we examine how sales are affected by three information sources for logistics services: online word of mouth (WOM) about logistics, self-reported logistics services, and expected delivery time. We use an instrumental variable method to address the endogeneity issue between sales and WOM. We find that, ceteris paribus, consumers give more weight to WOM about logistics and delivery time when they make purchase decisions but less weight to self-reported logistics service. The effects of logistics information on sales are asymmetric for large and small sellers.     

和谐人生:军队政治工作的价值诉求

军队政治工作就是做人的工作,要把关注广大官兵的“和谐人生”作为基本的价值诉求。军队政治工作应认真引导和帮助广大官兵确立和谐的人生理念,建立和谐的人际关系,调适和谐的心理机能,着力解决人生旅程中的现实问题,不断促进官兵的全面发展。     

一种完全分布式的空间服务及组合模型

针对服务组合中控制流和数据流的不同协调机制,可将组合模型分为4种类型,分别是控制流集中式且数据流集中式、控制流集中式且数据流分布式、控制流分布式且数据流集中式、控制流分布式且数据流分布式.空间服务组合流程需处理较大规模的数据流,采用控制流分布式和数据流分布式的协调机制能有效降低组合过程中系统整体通信规模并减少空间服务组合响应时间.通过对各种不同组合类型建模的定量分析对上述观点进行了正确性论证.模拟实验证明,定量分析结果可信.     

油料装备中发动机与油泵的匹配设计探讨

油料装备中发动机与油泵的合理匹配是设计中需解决的一个重要问题。介绍 了油料装备发动机与油泵的匹配原则,分析了油泵和发动机工作时所需的动力,发现发动机 在驱动油泵时具有一定的功率储备,尤其是共用发动机具有较大的功率储备,提出利用发动 机万有特性曲线进行匹配设计。     

A model of supply-chain decisions for resource sharing with an application to ventilator allocation to combat COVID-19

We present a stochastic optimization model for allocating and sharing a critical resource in the case of a pandemic. The demand for different entities peaks at different times, and an initial inventory for a central agency are to be allocated. The entities (states) may share the critical resource with a different state under a risk-averse condition. The model is applied to study the allocation of ventilator inventory in the COVID-19 pandemic by FEMA to different U.S. states. Findings suggest that if less than 60% of the ventilator inventory is available for non-COVID-19 patients, FEMA's stockpile of 20 000 ventilators (as of March 23, 2020) would be nearly adequate to meet the projected needs in slightly above average demand scenarios. However, when more than 75% of the available ventilator inventory must be reserved for non-COVID-19 patients, various degrees of shortfall are expected. In a severe case, where the demand is concentrated in the top-most quartile of the forecast confidence interval and states are not willing to share their stockpile of ventilators, the total shortfall over the planning horizon (until May 31, 2020) is about 232 000 ventilator days, with a peak shortfall of 17 200 ventilators on April 19, 2020. Results are also reported for a worst-case where the demand is at the upper limit of the 95% confidence interval. An important finding of this study is that a central agency (FEMA) can act as a coordinator for sharing critical resources that are in short supply over time to add efficiency in the system. Moreover, through properly managing risk-aversion of different entities (states) additional efficiency can be gained. An additional implication is that ramping up production early in the planning cycle allows to reduce shortfall significantly. An optimal timing of this production ramp-up consideration can be based on a cost-benefit analysis.     

地球模型偏差对远程弹箭弹道仿真的影响及修正

针对地球模型精确度影响远程弹箭弹道仿真的问题,分析了地球模型偏差对弹道仿真精度的影响并加以修正。采用总的地球椭球系,在已有弹道模型的基础上,分析了垂线偏差的产生机理及其对定向定位参数的影响,并由此得出弹道几何偏移随定向偏差的变化规律,研究了引力加速度初值偏差对弹道的误差累积,并对由水准面不平行性造成的实际落点高差进行了理论推导。对比仿真算例表明,考虑地球模型偏差影响的仿真结果与不考虑的情况下差别较明显,在远程条件下对弹道仿真精度的影响不容忽视。     

海军武器装备体系设计与评估技术研究

文章在分析海军武器装备体系内涵的基础上,提出了海军武器装备体系设计与评估的思路。在该思路的指导下构建海军武器装备体系设计与评估支撑系统,用来支撑装备体系设计与评估工作,对装备从体系层面开展研究与设计是一个有益的探索。     

海拔对离心泵吸入性能的影响

海拔对离心泵吸入性能影响较大,但对应关系不明确。为定量分析海拔与离心泵吸入性能的关系,需进行泵高原工作吸入性能实验。海拔与真空度关系密切,利用控制泵吸入口真空度的方法,开展泵高原工作吸入性能模拟实验,获取各工况下泵吸入口持液率数据,并绘制曲线图。实验结果表明：海拔每升高500 m,泵吸入口持液率下降2%~5%;随着海拔的提升,泵吸入性能下降速率加快,工作状态趋于不稳定。