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1.
液晶元件的电光特性由指向矢的再取向产生,通过外加电场可产生光轴.表面稳定化铁电液晶结构改变自然螺旋结构,引起电光响应,该响应具有高速度、大阈值和双稳性所要求的特性.描述了铁电液晶的开关状态对分子取向、温度和脉冲形状的动态响应,给出了表面稳定化铁电液晶的开关速度和能量.  相似文献   

2.
在503 K反铁电体PbZrO3发生立方-正交相变,序参量是反平行离子位移引起的超晶格;在低温相时,PbZrO3的反铁电超晶格反射强度随温度的变化成正比,可以由考虑量子效应的Landau唯象理论加以描述;高于室温时,Γ25超晶格反射强度显示了不同的温度依赖性。  相似文献   

3.
根据kittel型反铁电相变对称性的变化 ,选择轴矢量 R作为序参量是合适的。由Landau理论 ,相变温度附近的自由能F就可以写成 R幂级数展开的形式。令 F R=0 ,可得到关于序参量的方程 ,从而获得相变温度与自由能的关系  相似文献   

4.
仔细研究了PbTiO3电场感应铁电相的晶体结构。在初始反铁电相中,各离子位移方向与极轴垂直,但在外电场感应下,Pb离子沿极轴方向有相同方向0.17的位移,从而使晶体呈现铁电相特征,发生反铁电-铁电相变。此铁电相称之为电场感应铁(EFI)电相。通过结构对称性分析,确定EFI铁电相的对称性是C2mm(C2v),用极矢量Ps作为序参量来描述相变时对称性的变化是合适的。  相似文献   

5.
万鲁峰 《国防科技》2007,(12):21-24
随着航天技术的兴起及其在军事领域的应用,战场空间得到了极大的延伸,空间已经成为夺取战场主动权的制高点,夺取制天权成为夺取其他制权的先决条件.军事空间人才将在未来信息化战争中发挥重大作用.本文着眼于为满足未来信息化战争需要,军事空间人才应具备的能力素质,研究这些能力的培养对策.  相似文献   

6.
李林齐 《国防》2007,(7):72-72
随着军队中地方大学生干部队伍的逐年壮大,大学生干部成为部队建设中区别于生长干部的又一支重要力量.笔者发现,大学生干部和生长干部之间交流不多、各自为政的现象在一些单位不同程度存在,成为影响部队建设与发展的重要因素.  相似文献   

7.
信息是物质运动的状态和方式,在人类的战争活动中一直发挥着重要作用,因而交战双方的信息对抗活动从古至今一直都没有停息过.然而,信息对抗的焦点却不断地发生着变化.在经历过漫长的"信息获取焦点时期"和"信息传递焦点时期"后,当前"信息处理"已成为信息对抗的焦点.而随着科学技术的发展,"信息应用"极有可能成为未来信息对抗的新焦点.  相似文献   

8.
何银胜 《国防》2012,(9):27-29
21世纪,海洋成为提高综合国力和争夺战略优势的新领域.海军作为与海洋密切相关的战略力量,在维护海上通道安全、资源安全和主权安全上,肩负着光荣而艰巨的使命.随着经济全球化的趋势不断加深,世界各国对海洋资源的争夺日趋全球化,海军遂行远航任务走向常态成为必然.深入研究海军遂行远航任务动员保障工作问题,具有重大现实意义和深远历史意义.  相似文献   

9.
聂文新  龙仕鑫  马媛 《国防》2016,(12):60-62
在我国国防和军队改革实践不断深化的大背景下,军事智库日益成为现代领导管理体制中一个不可或缺的组成部分,成为国家软实力的一个重要标志.因此,建设新型军事智库,必须着眼中国实际,注重把握铸牢军魂、统合资源、健全机制等问题.  相似文献   

10.
恐怖主义已成为世界一大公害,这一特殊的暴力形式具有以下特征政治性的目的;多样性的暴力手段;使民众产生恐慌心理的作用;杀伤目标的宽泛性;错综复杂的形成原因等.我国在边疆地区也面临着恐怖活动的威胁.恐怖主义、民族分裂势力和宗教极端势力成为危害社会安定与发展的重大隐患.边防部门应合理利用自身优势,采取有效的防范与打击措施,保证社会主义各项事业的顺利进行.  相似文献   

11.
This article examines the implications of the proliferation of cyberwarfare capabilities for the character and frequency of war. Consideration of strategic logic, perceptions, and bargaining dynamics finds that the size of the effect of the proliferation of cyberwarfare capabilities on the frequency of war will probably be relatively small. This effect will not be constant across all situations; in some cases the advent of cyberwarfare capabilities may decrease the likelihood of war. On the other hand, the use of computer network attack as a brute force weapon will probably become increasingly frequent.  相似文献   

12.
The collapse of the Soviet Union precipitated the massive expansion of drug use and trade in Russia. The country now has one of the largest populations of injecting drug users in the world and has become the largest single-country market for Afghan heroin. In 2003 the Federal Service for the Control of the Drugs Trade was created to coordinate a comprehensive counternarcotics strategy appropriate to the scale of this threat. The service continues to face a number of challenges in its early stages of development. However, it has made considerable advances in improving responses to large-scale organised crime and in building international cooperation.  相似文献   

13.
为满足新型远程火箭炮战时技术保障仿真研究和战损规律研究需要,分析了该型火箭炮可能受到的威胁,建立了弹药破片场模型和该型火箭炮的几何描述模型,对该型火箭炮的战斗损伤进行了仿真,通过仿真可以得出某该型火箭炮的具体损伤程度及损伤概率.  相似文献   

14.
对于无向赋权图,利用换顶过程中矩阵翻转与数据块调换时上三角部分数据的变化规律,对权值矩阵的数据进行处理,以完成无向完全图中H圈(H路类似)的修正过程。事实上,多边修正的原理最终是通过变换顶点达到的,而其主要用到的换顶规则是矩阵数据的块调换与翻转,该思想还可以推广到有向图的情形。最后利用换顶原理对多边修正算法进行了复杂性分析,讨论修正边数对复杂性的影响。  相似文献   

15.
In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.  相似文献   

16.
运用当前国际上最流行的MATLAB软件及SIMULINK软件包,对8-300柴油机带水力测功器系统进行了PID控制器的设计及仿真,并分析了仿真结果,最后得出了对实现该系统控制有重要价值的PID控制器.  相似文献   

17.
武器跟踪随动仿真系统是一个能够对武器跟瞄进行演示验证的虚拟现实系统,对虚拟军事训练的研究和探索,有着极其重要的意义。提出了一种简易的跟踪随动算法,可以对武器跟瞄运动目标进行有效的模拟;并建立VegaPrime与OpenGL混合编程机制解决了在场景中的画图问题,实现了对瞄准镜十字刻线的绘制;通过实验,实现了在计算机系统中一定范围的全天候自然实景的模拟。开发和应用结果表明,该方法具有可行性,仿真产生的图像与实际成像较为接近,并能大幅度减少训练成本。上述研究对于武器瞄准训练以及目标识别等具有一定的工程意义。  相似文献   

18.
中国式建筑的困境在于附加意识形态性的起源和前因后果的关系倒置.近现代建筑进入中国后,曾经保持着与世界的同步发展,直至20世纪50年代初.中国式建筑是伴随着中西古今之争而产生的命题,建筑被赋予了意识形态的内容.在全球化背景下,重新认识中国式建筑产生和发展的局限性,其实质在于混淆了现代化与西方化之区别,将现代化等同于西方化...  相似文献   

19.
The debris from exploded buildings can ricochet after colliding with the ground, thus increasing the debris travel distance and danger from any associated impacts or collisions. To reduce this danger, the travel distance of ricocheted debris must be accurately predicted. This study analyzed the change in the travel distance of ricocheted concrete debris relative to changes in the properties of a sand medium. Direct shear tests were conducted to measure the change in internal friction angle as a function of temperature and water content of the sand. Finite element analysis (FEA) was then applied to these variables to predict the speed and angle of the debris after ricochet. The FEA results were compared with results of low-speed ricochet experiments, which employed variable temperature and water content. The travel distance of the debris was calculated using MATLAB, via trajectory equations considering the drag coefficient. As the internal friction angle decreased, the shear stress decreased, leading to deeper penetration of the debris into the sand. As the loss of kinetic energy increased, the velocity and travel distance of the ricocheted debris decreased. Changes in the ricochet velocity and travel distance of the debris, according to changes in the internal friction angle, indicated that the debris was affected by the environment.  相似文献   

20.
In September 2011, the Commander of the International Security Assistance Force (ISAF) in Afghanistan directed the Afghan Assessment Group to redesign the way in which ISAF was assessing the status of the war, and to be ‘revolutionary’ in so doing. The resulting assessment paradigm was novel, non-doctrinal, and effectively addressed the unique complexities of the counterinsurgency in Afghanistan and the needs of the ISAF Commander. It had a two-tier structure consisting of both strategic and campaign assessments. The former focused on answering a set of strategic questions in narrative, analytic form to address the strategic environment, while the latter used a set of standards and accompanying narrative responses to gauge accomplishment of campaign tasks. Both tiers captured the current state of the war while maintaining an eye on future challenges and opportunities. The two assessments and their associated processes were designed to stimulate discussions leading directly to decisions by senior leaders on actions they could take, direct, or request. While any assessment paradigm will have advantages and disadvantages, an examination of the pros and cons of this assessment paradigm makes clear that it should be considered a ‘best practice’ in the field of counterinsurgency assessment.  相似文献   

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