Q∝T~n时不可逆卡诺热泵的最优性能

非线性传热条件下的内可逆卡诺热机最优性能有了一些讨论,本文将导出不可逆卡诺热泵工作于非线性传热 Q■条件下,最佳供热系数д与泵热率π的关系。据此可确定任意泵热率时所对应的供热系数界限。最后,讨论了这一关系的一些应用,所得结果包含了经典热力学及内可逆线性传热情况下的有关结论,为实际热泵设计提供新的理论依据。     

1／2自旋量子热泵的生态学优化性能

研究以１／２自旋量子费密系统为工质的内可逆卡诺热泵的生态学优化性能,得到了Ｅ目标最大时量子热泵的最佳泵热率、最佳致热系数以及最佳熵产率。     

传热规律对卡诺热泵有限时间(火用)经济最优性能的影响

本文导出了一种较为普遍的传热规律 q∝△(T~n)时内可逆卡诺热泵的最佳供热系数、利润率关系,并藉此讨论了几种传热规律时内可逆卡诺热泵的有限时间(火用)经济最优性能,得到了一些新的普适结果。     

具有等熵压缩、膨胀过程的回热式布雷顿热泵循环有限时间热力学性能

研究恒温和变温热源条件下具有等熵压缩、膨胀过程的闭式回热式布雷顿热泵循环有限时间热力学性能,导出循环供热率和供热系数与循环压比间的解析关系,由此可得最佳供热率、供热系数关系。分析中计入了工质与高、低温热源间换热器和回热器的热阻损失。     

一类较为完善的不可逆制冷机模型及其最优化

在考虑工质与热源间热阻损失的内可逆卡诺制冷机模型基础上,用一常数项表示热源间的热漏,用一常系数项表示循环中除热阻和热漏外的其余所有不可逆性（如摩擦、涡流、惯性效应等）,提出了一类较为完善的不可逆卡诺制冷机模型,并对此不可逆制冷机模型进行优化分析,导出了其最佳制冷率与制冷系数间的优化关系和最大制冷系数及其相应的制冷率。由定义的一常数项和一常系数项可定性、定量地分析不可逆性对循环性能的影响,所得结果包含了有关文献的一些特例。最后,给出了详细的数值算例,说明本模型的有效性。     

具有热阻、热漏和内不可逆性的联合卡诺热机生态学优化

用有限时间热力学的方法分析具有热阻、热漏、内不可逆性的定常流联合卡诺型热机循环.导出了在傅立叶导热定律下联合循环功率、效率和生态学指标的性能,并进行优化;得到功率、效率和生态学指标之间的优化关系,并由数值计算分析了功率、效率和循环熵产率之间的关系.所得的结果表明,最大生态学指标下的效率十分接近于联合循环可以达到的最大效率;相应的熵产率也要低于以输出功率为优化目标时的熵产率.     

化学反应驱动热机的功率优化

本文基于一级和二级化学反应动力学理论,讨论化学反应驱动有限热容热源内可逆卡诺热机系统的功率优化问题,得到了一些新的结果。     

不可逆定常态流热机的有限时间热力学最优化

在考虑工质与热源间热阻损失的内可逆热机模型基础上,用一常数项表示热漏损失,用一常系数项表示循环中除热阻和热漏外的其余不可逆性（如摩擦、涡流、非平衡等）,建立了一个不可逆定常态能量转换卡诺热机模型,并对其进行有限时间热力学分析,导出循环的最佳功率与效率关系,并得到了最大功率及其相应的效率和最大效率及其相应的功率。由此模型可准确描述各种不可逆性对热机性能的影响。由此得到的热机功率效率特性与实际热机特性相同。     

有限时间制冷机生态学的优化性能

本文研究非线性传热Ｑｏ∝（△Ｔ）￣ｎ条件下的内可逆卡诺制冷机,给出可逆与不可逆循环的制冷量之间的关系式,由此建立了制冷机生态学的优化目标Ｆ,并求得Ｆ与制冷系数的最优关系,最后讨论制冷机生态学的工作优域,为更有效地利用能量和保护自然资源提供新的依据。     

具有热阻、热漏和内部耗散的联合制冷机性能

建立一类存在热阻、热漏和内部耗散的定常态流联合制冷机循环模型,并研究其性能优化,导出制冷系数、制冷率基本优化关系和最大制冷系数及其相应的制冷率．给出了传热面积的最佳值和工质最佳工作温度．所得结果适用于由任意个制冷机串接而成的联合制冷循环．     

Reviews

Douglas S. Derrer, We Are All the Target: A Handbook of Terrorism Avoidance and Hostage Survival. Annapolis, MD: US Naval Institute Press, 1992. Pp. x+135, notes, index. $14.95. ISBN 01–55750–150–5

Ian Knight, Zulu: Isandlwana and Rorke's Drift, 22–23 January 1879. London: Windrow & Greene, 1992. Pp.136, 150 illus., incl 8 colour plates, maps, biblio. £35. ISBN 1–872004–23–7

Ian Knight, By the Orders of the Great White Queen: Campaigning in Zululand through the Eyes of the British Soldiers, 1879. London: Greenhill Books and Novato: Presidio Press, 1992. Pp. 272, 17 illus., 1 map. £18.95. ISBN 1–85367–122–3

Manfried Rauchensteiner and Erwin A. Schmidl (eds.), Formen des Krieges: vom Mittelalter zum ‘Low‐intensity’ Conflict’. Graz : Verlag Styria, 1991. Pp.208. DM35. ISBN 3–22–12139–7

Harold J. Kearsley, Maritime Power and the Twenty‐First Century. Dartmouth: Dartmouth Publishing Company, Limited, 1992. Pp.xv + 203, 13 diagrams, index. £32.50. ISBN 1–85521–288–9     

Panjwai: a tale of two COINs in Afghanistan

The US Army has two approaches to counterinsurgency operations in Afghanistan. One is hard, or combat-focused, and the other is soft, or development-focused. This study examines two US Army task forces deployed to Panjwai District, Afghanistan from 2012 to 2013. CTF 4-9 and 1-38 offer a meaningful comparison because they pursued these contrasting approaches among the same population and against the same enemy at the same time and place. The study compares each unit’s approach and finds that neither approach was successful absent the other. The article concludes by recommending further research into combining the approaches at the operational level.     

线性核时频信号表示及其仿真

根据ｃｈｉｒｐ信号在模糊域的特点,本文提出了线性核时频表示方法。这种方法在提高分辨率、消除交叉项以及抑制噪声等方面都具有较高的性能。理论分析和实验结果都证实了这种方法的有效性     

Putin – the masked nemesis of the strategy of ambiguity

Recent events demonstrate the complex and adaptive approach employed by Russia to reassert influence in Europe. The changing face of Russia’s strategy commenced in 2007 when it launched a crippling cyber-attack against Estonia. This was followed by a large Russian conventional attack against Georgia in 2008, occupying two large areas of the nation. 2014 witnessed the Russian annexation of Crimea where in just a week, Russia seized control of Crimea “without firing a shot.” The annexation of Crimea was rapidly followed by a Russian inspired and led subversive war in eastern Ukraine. The common thread among these diverse Russian operations is its use of ambiguity to confound and confuse decision makers in the West.     

Forecasting a Hurricane: Israeli and American Estimations of the Khomeini Revolution

The surprising ‘Arab Spring’ raises the question as to what would enable national intelligence to provide high quality warnings prior to the eruption of popular revolutions. This article uses new sources of evidence to trace and explain Israel's success in comparison to US failure at correctly estimating the course of the Iranian Revolution in 1977–79. In explaining this variance, the article shows that it was mainly the result of the intimate acquaintance of Israel's representatives in Iran with the local language, history and culture, as well as the ability to communicate with locals – tools which the Americans completely lacked.     

关于教师继续教育培训模式的思考

继续教育作为终身教育的重要组成部分和基本形式,对教师的发展成长意义重大。继续教育工作开展十多年来,取得了一定的成绩,但还存在不少问题,如学习动机较为被动,管理认识不到位,教学内容陈旧空泛,教学方法呆板机械等。随着课程改革的不断深入,继续教育必须采取相应的改进措施,树立以人为本,服务至上的观点,教学内容的前瞻性与实用性并重,教学人员进行整合,教学方法灵活多样,评价考核规范科学等,以此激活受训教师内在的学习动机,更大程度地提高继续教育培训的实际效果。     

用DirectShow实现网络视频

目前市场上的网络监控技术一般用昂贵的硬件设备来支撑,投资较大。在深入研究微软的DirectX9.0的基础上,提出如何用DirectShow软件技术和普通的数字摄像头来实现网络视频的监控和实现技术,内容涉及通信协议、视频的编码与解码技术、视频的编码格式和COM组件编程技术等,最终的实验结果令人满意,且费用低廉,技术可靠,为在高速局域网内构建视频监控系统提供有效的技术支持。     

Interpreting the Ribchester Helmet

In 1796 a 13-year-old boy playing on wasteland behind his father’s house in Ribchester, Lancashire discovered an assemblage of over 30 Roman artefacts, including a decorated brass helmet. Although partially corroded the Ribchester helmet is a fine example of a first-century AD cavalry sports helmet. This article considers how the interpretation of the helmet has evolved since its discovery. The multi-faceted iconography of the helmet with its mural crown diadem is that of an elite soldier and is paralleled in other examples of cavalry sports helmets of the Ribchester type. The long-neglected imagery on the helmet bowl is reinterpreted and seen not as a haphazard collection of randomly placed combatants but as a highly structured, symmetrical composition specifically designed to be viewed from different directions.     

Desert insurgency: lessons from the third Tuareg rebellion

This article provides an in-depth examination and analysis of the 2006–2009 Tuareg rebellion in Mali and Niger. It identifies the underlying reasons behind the rebellion, explores contrasting counter-insurgency (COIN) strategies employed by the two governments, and presents some lessons learned. While both COIN approaches ultimately produced similar peace settlements, the article argues that the Malian strategy of reconciliation combined with the selective use of force was far more effective than the Nigerien iron fist approach at limiting the size and scope of the insurgency and producing a more sustainable peace. It concludes by looking at the role of external actors, particularly the United States, and how the failure to internationalize the conflict was actually more beneficial to the local COIN effort, as well as to the longer strategic interests of the United States in the region.