短脉冲激光作用下丙酮液池的沸腾研究

采用短脉冲激光加热浸没在丙酮液体里的铂金属薄膜的实验方法并结合数值模拟计算 ,研究了高温升率条件下丙酮液体温度场随时间的变化规律及汽泡行为 ,得出了丙酮液池温度边界层的数量级大约为 4 0～ 70μm,确定了铂镀层表面的反射损失 ,认为薄汽膜的形成和热边界层外移 ,是激光脉冲过后很长一段时间内汽泡依然长大的主要原因     

信息战战场分析模型

根据区域攻防的不同战场信息行动,建立3个非线性微分方程模型.以防御方的总射击速率和战斗力消耗率作为评价指标,着重探讨了进攻方的指挥控制系统、侦察监视系统、战毁评估系统和火力系统之间的性能匹配关系.     

姿态测量/激光测距的无人机目标定位模型

无人机在支持舰炮对岸火力支援中,需要实时向射击指挥员提供满足精度要求的目标坐标.目前我军某型无人机采用的实时目标定位模型在复杂地形条件下存在较大原理误差,且缺乏对机动目标的连续定位能力.针对这一情况,给出了一种基于姿态测量/激光测距的目标定位模型.经误差仿真,复杂地形连续定位精度满足作战要求.     

脉冲激光测距机测程指标的自动快速检测

分析了目前验收脉冲激光测距机测程指标所采用的方法——“消光法”存在的不足,并在“消光法”的基础上,通过采用计算机技术、准激光技术和延时模拟空间距离的方法,实现了测程指标自动、快速和不解体检测     

Performance analysis of queue length monitoring of M/G/1 systems

This study investigates the statistical process control application for monitoring queue length data in M/G/1 systems. Specifically, we studied the average run length (ARL) characteristics of two different control charts for detecting changes in system utilization. First, the nL chart monitors the sums of successive queue length samples by subgrouping individual observations with sample size n. Next is the individual chart with a warning zone whose control scheme is specified by two pairs of parameters, (upper control limit, d_u) and (lower control limit, d_l), as proposed by Bhat and Rao (Oper Res 20 (1972) 955–966). We will present approaches to calculate ARL for the two types of control charts using the Markov chain formulation and also investigate the effects of parameters of the control charts to provide useful design guidelines for better performance. Extensive numerical results are included for illustration. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

HF化学激光器燃烧室中燃料配比的数值分析

利用最小自由能法及质量流量守恒原则,对HF化学激光器的NF3-D2-He体系的化学平衡组分进行了计算,提出了F原子摩尔流量密度参量,分析了各输入气流的流量调节对燃烧室总温、总压、F原子产率等的影响.在燃料配比不变的情况下,总流量的增加使得F原子流量也成比例增加,而由此带来的总压升高引起的F2解离度、绝热燃烧温度、F原子...     

Periodic review inventory management with contingent use of two freight modes with fixed costs

We study a stochastic inventory model of a firm that periodically orders a product from a make‐to‐order manufacturer. Orders can be shipped by a combination of two freight modes that differ in lead‐times and costs, although orders are not allowed to cross. Placing an order as well as each use of each freight mode has a fixed and a quantity proportional cost. The decision of how to allocate units between the two freight modes utilizes information about demand during the completion of manufacturing. We derive the optimal freight mode allocation policy, and show that the optimal policy for placing orders is not an (s,S) policy in general. We provide tight bounds for the optimal policy that can be calculated by solving single period problems. Our analysis enables insights into the structure of the optimal policy specifying the conditions under which it simplifies to an (s,S) policy. We characterize the best (s,S) policy for our model, and through extensive numerical investigation show that its performance is comparable with the optimal policy in most cases. Our numerical study also sheds light on the benefits of the dual freight model over the single freight models. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

石化企业火灾事故原因调查方法和技术研究

根据石油化工企业生产特点,阐述了石油化工企业火灾现场特点、火灾事故调查的重点内容、调查采取的方法和技术以及事故调查当中的注意事项,为开展好石油化工企业火灾调查工作提供参考。     

Analysis of decentralized multi‐product pull systems with lost sales

We study a pull‐type, flexible, multi‐product, and multi‐stage production/inventory system with decentralized two‐card kanban control policies. Each stage involves a processor and two buffers with finite target levels. Production stages, arranged in series, can process several product types one at a time. Transportation of semi‐finished parts from one stage to another is performed in fixed lot sizes. The exact analysis is mathematically intractable even for smaller systems. We present a robust approximation algorithm to model two‐card kanban systems with batch transfers under arbitrary complexity. The algorithm uses phase‐type modeling to find effective processing times and busy period analysis to identify delays among product types in resource contention. Our algorithm reduces the effort required for estimating performance measures by a considerable margin and resolves the state–space explosion problem of analytical approaches. Using this analytical tool, we present new findings for a better understanding of some tactical and operational issues. We show that flow of material in small procurement sizes smoothes flow of information within the system, but also necessitates more frequent shipments between stages, raising the risk of late delivery. Balancing the risk of information delays vis‐à‐vis shipment delays is critical for the success of two‐card kanban systems. Although product variety causes time wasted in setup operations, it also facilitates relatively short production cycles enabling processors to switch from one product type to another more rapidly. The latter point is crucial especially in high‐demand environments. Increasing production line size prevents quick response to customer demand, but it may improve system performance if the vendor lead‐time is long or subject to high variation. Finally, variability in transportation and processing times causes the most damage if it arises at stages closer to the customer. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007     

Quantifying the performance effects of idle time utilization in multiserver systems

In many practical multiserver queueing systems, servers not only serve randomly arriving customers but also work on the secondary jobs with infinite backlog during their idle time. In this paper, we propose a c‐server model with a two‐threshold policy, denoted by (e d), to evaluate the performance of this class of systems. With such a policy, when the number of idle servers has reached d (<c), then e (<d) idle agents will process secondary jobs. These e servers keep working on the secondary jobs until they find waiting customers exist in the system at a secondary job completion instant. Using the matrix analytic method, we obtain the stationary performance measures for evaluating different (e, d) policies. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007.