加工中心用触发式测头系统监测方法研究

主要研究了在数控加工中心ARROW500上使用触发式测头(英国Renishaw的MP12测头)实现零件加工的自动监测,通过深入研究用触发式测头在加工中心上实现在线监测的方法,使加工零件的序前调整、找正,序中监控及序后测量等可自动完成,实现了加工中心高效率、高自动化的监测。     

延时下基于事件触发的多智能体系统一致性

研究了通信延时下基于事件触发的一阶多智能体系统一致性问题。针对有向固定拓扑,设计了通信延时下基于事件触发机制的控制器。利用李雅普诺夫稳定性理论提出了能够使系统稳定和一致的事件触发函数和时延上界,并利用该事件触发规则求取两次触发之间的最小间隔,证明了该系统不存在Zeno行为。事件触发机制的引入有效减少了控制器的更新次数和智能体之间的通信频率,节约了资源,最后通过仿真实例验证了该理论方法的可行性与有效性。     

一种对雷达射频掩护的干扰方法研究

首先分析了噪声干扰以及基于下降沿触发式的相参干扰在对抗雷达射频掩护中的不足,着重在干扰反应时间及频率捷变信号适应性等方面展开研究,指出了基于下降沿触发式的相参干扰反应时间长、易被操作手识别,且无法适应频率捷变信号等缺陷。为此,提出了基于脉冲簇识别的干扰方法,分析了该方法在对抗雷达射频掩护中的优势,并进行了仿真,验证了其有效性。     

超精密气浮式电容传感器系统

介绍了一种高精度、高分辨率的超精密气浮式电容传感器。该系统将具有方形导轨的气浮测头和超小型电容传感器结合在一起,既保证了测头的高分辨率,又体现了电容传感器的高精度、高频响的特点,是一种较好的用于超精密接触测量的测量系统     

事件触发的时滞二阶多UAV系统一致性控制

研究具有固定输入时滞的二阶多无人机系统在事件触发下进行不完全随机采样,并达到一致性控制的问题。提出一种阈值依赖于多无人机系统事件触发时刻和初始状态的事件触发机制,并给出在此事件触发机制下具有固定输入时滞二阶多无人机系统的分布式控制策略。当无人机自身状态变化量满足触发条件时,无人机间进行信息交互,控制器根据此次事件触发的采样状态值进行控制输入更新。通过理论推理证明一致性控制的结论。最后,通过仿真验证了算法的有效性。     

基于事件触发的船舶航向自适应控制研究

针对非线性船舶航向控制系统,充分考虑系统具有未知常数参数,从执行机构实际出发构造触发事件并基于反步法设计控制器输入信号,提出了基于事件触发的自适应控制器的设计方法。理论证明及仿真分析表明,基于事件触发的自适应控制器在保障系统稳定的同时,实现了系统输出对指令信号的良好、快速的跟踪效果,提高了执行机构的执行效率。     

一种大功率晶闸管触发电路设计

根据晶闸管门极特性曲线和开关装置主回路特性,计算出触发脉冲幅值、频率、上升时间等关键参数;设计隔离驱动电路,对脉冲结束时变压器初、次级电路进行分析,给出了初、次级等效电路模型和触发电路参数的选取公式。实验验证表明:利用该触发电路可对脉冲功率开关在-40℃~100℃的宽温度范围内实现可靠触发,得到脉宽为30μs、脉冲前沿小于3μs、顶降小于3%的脉冲波形,该实验结果和理论分析基本一致。     

单级磁阻型线圈发射器能量转换效率研究

对单级磁阻型线圈发射器进行了理论分析,利用电磁场有限元计算与外电路相结合的方法,分析了电参数、弹头形状及初始触发位置对单级磁阻型线圈发射器能量转换效率的影响.结果表明:能量转换效率随电压和电容的增大而增大;存在最佳的弹头形状及弹丸初始触发位置,使能量转换效率达到最佳.     

基于呼叫状态的IMS业务触发算法

在IMS会话和和业务控制过程中,随着业务量的增长,S-CSCF面临的负载急剧增加,3GPP原有IMS业务的集中控制方式极易形成性能“瓶颈”,从而影响系统服务质量。为降低会话时延,提高系统性能,本文在研究基于分组的业务触发算法和基于呼叫状态的业务触发算法基础上,提出了一种基于呼叫状态的分组业务触发算法（C-GSTA）,并对其进行性能建模和理论分析。仿真结果表明,在业务种类和业务量增加的情况下,C-GSTA算法能够有效降低S-CSCF与服务器之间的信令流量,提高IMS系统吞吐量,缩短S-CSCF处理时延,改善业务触发性能和网络服务质量。     

M739引信头部触发机构发火模式与判别方法研究

针对M739引信头部机构的基本结构与特性,分析其头部触发机构的发火原理,提出发火模式种类的判别方法。结合某型引信的具体参数,计算其对钢板、胶合板和地面三种不同目标介质射击时的碰击力,分析碰击力、防雨机构静态下移抗力及支筒图定抗力对发火模式的影响。试验结果表明,该发火模式判别方法适用于M739系列引信。     

应科学规范地组织实施心理行为训练

心理行为训练在武警部队得到了越来越广泛的应用,但是它专业技术性比较强,有一套系统科学的训练程序和规范要求。如果不按科学规律办事,缺乏严密的组织,不仅达不到心理行为训练的预期效果,还可能导致受训人员出现心理反应。因此,要提高心理行为训练的有效性,就必须科学规范地组织施训。     

药库管理系数据库的设计与实现

从信息管理系统的模式出发,分析了系统的结构模式,并对由此产生的并发控制问题,应用时间戳法进行了分析处理,用触发器存储过程解决了对数据的随时更新问题。本系统以Sybase作为数据库,设计并实现了药库管理系统。     

Being there: US Navy organisational culture and the forward presence debate

ABSTRACT

This article argues that the US Navy’s roles (which have historically been bifurcated between warfighting and political use of force) manifest in its organisational culture as two different concepts of war: the US Navy as diplomatic actor and the US Navy as warfighting force. The conflict between these different concepts of war can be seen in the current debate about the definition and function of presence. The debate about presence is not just theoretical, but represents a deep and enduring conflict within the Navy as an organisation about its concept of war. Since the end of WWII, the Navy has been designing its fleet architecture according to a Mahanian concept of war, despite the preponderance of non-lethal missions and activities. The result is a mismatch between platforms and tasks.     

Some comparative & design aspects of fixed cycle production systems

A serial production line is defined wherein a unit is produced if, and only if, all machines are functioning. A single buffer stock with finite capacity is to be placed immediately after one of the first N-1 machines in the N machine line. When all machines have equal probability of failure it is shown that the optimal buffer position is exactly in the middle of the line. This result is synthesized with the earlier work of Koenigsberg and Buzacott including an analysis of the covariance between transition states. An alternative model formulation is presented and integrated with previous results. Finally, a sufficient condition and solution procedure is derived for the installation of a buffer where there is a possible trade-off between increasing the reliability of the line versus adding a buffer stock.     

Investigation of normal,lateral, and oblique impact of microscale projectiles into unidirectional glass/epoxy composites

Spacesuits and spacecraft must endure high velocity impacts from micrometeoroids. This work considers the impact of 100 μm diameter projectiles into composite targets at velocities from 0.5 km/s to 2 km/s. This work begins by presenting an energy-based theoretical model relating depth of penetration (DoP) and impact force to impact velocity, characteristic time, and threshold velocity and force. Next, this work compares numerical simulations of normal impact on composites to the theoretical model. Numerical simulations are conducted with LS-DYNA and the well-known composite model, MAT-162. The numerical models consider unidirectional S2-glass fiber reinforced SC-15 epoxy composite laminates. The numerical model shows good correlation with the theoretical model. The numerical model also investigates lateral impact, parallel to the fiber direction, and oblique impact at angles from 30° to 82.5°. This work decomposes oblique impact into normal and lateral components, and compares them with normal and lateral impact results. The results show good correlation of the normal component of oblique results with the theoretical model. This numerical and theoretical study focuses on DoP, velocity, and penetration resistance force as functions of time. The theoretical model and numerical simulations are used to determine new DoP parameters: characteristic time of depth of penetration and threshold impact velocity. These models are a first step in developing the capability to predict DoP for oblique, microscale, high-speed impact on composite materials.     

底质对潜坐结构吸附力的试验研究

通过对圆底模型与方底模型的理论分析和试验研究,提出了对坐沉海底的两种形状结构体在离底时需要克服的底质吸附力的估算方法．通过建立理论分析模型,将底质种类对离底力的影响包括在估算公式内,从而可以对不同种类的底质对坐沉结构体的吸附力进行计算．     

论建立综合的装备保障理论体系

装备保障已成为一个极其重要的和独立的军事活动 ,建立综合的装备保障理论体系是装备保障发展的客观要求 ,也是军事学科发展的现实需求。分析了装备保障与后勤保障的关系 ,装备保障理论体系与后勤保障理论体系的边界划分 ,装备保障理论体系的学科归属 ,最后对装备保障理论体系的构建进行了分析     

Research on fuze microswitch based on corona discharge effect

Abnormal voltages such as electrostatic, constant current, and strong electromagnetic signals can erro-neously trigger operation of MEMS pyrotechnics and control systems in a fuze, which may result in casualties. This study designs a solid-state micro-scale switch by combining the corona gas discharge theory of asymmetric electric fields and Peek's Law. The MEMS switch can be transferred from "off" to"on" through the gas breakdown between the corona electrodes. In the model, one of the two electrodes is spherical and the other flat, so a non-uniform electric field is formed around the electrodes. The theoretical work is as follows. First, the relation among the radius of curvature of the spherical electrode, the discharge gap, and the air breakdown voltage is obtained; to meet the low voltage (30-60 V) required to drive the MEMS switch, the radius of curvature of the spherical electrode needs to be 10-50 μm and the discharge gap between the two electrodes needs to be 9-11 μm. Second, the optimal ratio ε is introduced to parameterize the model. Finally, the corona discharge structural parameters are determined by comparing the theoretical and electric field simulation results. The switch is then fabricated via MEMS processing. A hardware test platform is built and the performing chip tested. It is found that when the electrode gap is 9 μm, the electrostatic voltage is at least 37.3 V, with an error of 2.6% between the actual and theoretical air breakdown voltages. When the electrode gap is 11 μm, the electrostatic voltage is at least 42.3 V, with an error of 10.5% between the actual and theoretical air breakdown voltages. Both cases meet the design requirements.     

The Keynesian IS-MR Model and Military Spending

The issue of guns or butter is one of the most fundamental economic questions, yet there is no consensus on a theoretical framework for examining it. Over the last decade, a version of a simple Keynesian macroeconomic model has been applied a number of times to examining the link between defence spending and economic growth in a range of countries. There are reasons for doubting the soundness of this model as a basis for empirical work.