Effect of the end cap on the fragment velocity distribution of a cylindrical cased charge

The prediction of the fragment velocity distribution of a cylindrical cased charge with end caps is one of the key issues to assess the damage efficiency of the warhead. However, limited work has been con-ducted to predict the fragment velocity distributions along the axis of cylindrical cased charges with end caps. This paper presents a study of the velocity distribution of fragments caused by the explosion of a cylindrical cased charge with end caps. The fragment velocity distribution and the end cap velocity were determined by an X-ray radiography method, and the axial fragment distribution was determined by witness plates. It was found that the velocities of fragments, especially near the edge, were increased when the end caps were added, and the position of maximum velocity is closer to the non-detonation end. The fragment velocities were increased, and the fragment projection range was decreased with the increase of the thickness of the end cap. A formula for fragment velocity distributions of a cylindrical cased charge with end caps, which is based on Huang's formula, was proposed by the theoretical analysis and data fitting and validated experimentally. The results indicate that the proposed formula is accurate in predicting the fragment velocity distribution along the axis of a cylindrical cased charge with end caps detonated at one end.     

On the asymptotic optimality of algorithms for the flow shop problem with release dates

We consider the nonpermutation flow shop problem with release dates, with the objective of minimizing the sum of the weighted completion times on the final machine. Since the problem is NP‐hard, we focus on the analysis of the performance of several approximation algorithms, all of which are related to the classical Weighted Shortest Processing Time Among Available Jobs heuristic. In particular, we perform a probabilistic analysis and prove that two online heuristics and one offline heuristic are asymptotically optimal. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

战后美苏矛盾的演变与冷战的开始

第二次世界大战末期及战后初期,由于政治、经济、军事利益的尖锐对立,美苏矛盾迅速上升。为了达到自己的目的,它们确定新的战略策略,争夺势力范围,并把欧洲作为争夺的重点。但是,世界大战的惨痛记忆使美苏都不敢贸然发动战争,只是以冷战的形态对抗。     

中流砥柱--八路军对抗日民族解放战争的历史贡献

抗日战争中,八路军在中国共产党的领导下,深入敌后创建抗日根据地,开展抗日游击战争,浴血奋战,为夺取抗日战争的伟大胜利作出了巨大贡献.     

试论政治工作的信息建模

政治工作信息建模是信息技术与政治工作有机融合的基本条件和关键环节。推动政治工作信息化建设应认识政治工作信息建模的重要作用,整理政治工作信息建模的基本方法,科学评价不同建模方法的适用范围和有效性,全面把握政治工作信息建模的复杂性和可行性。     

强化战斗精神要体现在全面提高素质能力上

强化战斗精神培育一个十分重要的方面,就是要体现在全面提高素质能力上。要深刻认识把强化战斗精神体现在全面提高素质能力上的重要意义,牢牢把握关键环节,并自觉坚持正确的途径。     

浅析中共在南昌起义过程中的决策特点

中共对南昌起义的一系列指导,不仅体现在起义的酝酿、决策阶段,还体现在起义爆发后南征途中。其中包括指示广东、湖南等省发动暴动配合起义以及做好起义失败后的善后工作等。纵观中共对南昌起义的系列指导和举措,可以看出其中贯穿一条鲜明的主线,就是紧紧围绕着"民众武装暴动"这一政策。早在南昌起义发动之前,中共就决定在湘鄂粤赣四省发动农民秋收暴动,所以中共对南昌起义的指导离不开这一既定方针。同时,中共中央关于暴动主要依靠群众,军事力量只是副力的思想严重影响着其对南昌起义的领导和评价,而共产国际的"指导"直接左右中共对南昌起义的决策。     

火力演进与陆军战术变革的回顾

自从火药发明并应用于军事领域之后,战争便逐渐步入热兵器时代。此后,陆军火力随着武器装备的发展不断发生变化,陆军战术因此在400余年的时间里经历了4次大的变革,分别是前装药滑膛火器时期的线式和纵队战术、后装药线膛火器时期的散兵线战术、机械化系列火器时期的诸兵种合同战术和信息促成火器融合时期的多军种联合战术。     

MAS中Agent属性冲突形式化描述及消解系统研究

由于多智能体系统(MAS)中各个Agent具有自治性、分布性和异构性等特征,导致MAS内部经常会出现冲突现象。首先,运用数学方法对MAS中存在的属性冲突进行形式化描述,并将其分为6类,针对每类冲突提出了相应的消解对策。其次,对属性冲突智能消解系统(AACIRS)流程框架进行了分析,并在此基础上建立了AACIRS系统,实现了MAS中属性冲突的消解。从而为解决MAS中Agent属性冲突提供了解决方案,为MAS的稳定运行提供了技术保证。     

Irreducibility of joint inventory positions in an assemble‐to‐order system under (r,nQ) policies

In a typical assemble‐to‐order system, a customer order may request multiple items, and the order may not be filled if any of the requested items are out of stock. A key customer service measure when unfilled orders are backordered is the order‐based backorder level. To evaluate this crucial performance measure, a fundamental question is whether the stationary joint inventory positions follow an independent and uniform distribution. In this context, this is equivalent to the irreducibility of the Markov chain formed by the joint inventory positions. This article presents a necessary and sufficient condition for the irreducibility of such a Markov chain through a set of simultaneous Diophantine equations. This result also leads to sufficient conditions that are more general than those in the published reports. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011