基于整车虚拟道路行驶试验的车辆零部件疲劳分析

针对现有车辆零部件精确疲劳分析依赖成本高昂的实车试验的问题,提出了一种利用整车虚拟样机仿真分析零部件疲劳寿命的方法。该方法通过在ADAMS/CAR中用整车虚拟样机在虚拟道路模型上进行行驶试验,利用多体系统动力学基于模态坐标的求解特点,使用模态应力恢复技术准确还原出了用于零部件疲劳寿命分析的载荷历程。将该方法应用于某车辆双横臂前悬中的下控制臂,在较短的时间内获得了该零件的预测疲劳寿命、寿命安全系数及危险部位等信息。应用结果表明,该方法可作为汽车设计过程与测试过程中的有效试验手段。     

高陡度非球面磨削亚表面损伤深度规律

具有高陡度非球面特性的光学元件可以明显改善光学系统的空气动力学性能,从而提升和优化系统综合性能。磨削加工方法可以作为此类元件的前期加工工序,而磨削难免会造成零件的亚表面损伤,且在这种高陡度非球面磨削加工中磨削参数是实时变化的,造成整个工件亚表面损伤深度不一致。针对这种情况,建立亚表面损伤预测模型,并结合半球形砂轮磨削的特点,通过理论计算预测非球面磨削亚表面损伤深度分布规律。在此基础上,以热压多晶氟化镁平面为对象进行模拟参数实验,通过磁流变抛斑点法得到各组参数下亚表面损伤深度情况,结果显示损伤深度范围在12.79μm~20.96μm之间,且沿试件半径方向由内向外呈增大趋势,结果与预测模型相吻合。     

The Production and Deposition of the Guisborough Helmet

In September 1878 the British Museum received a donation of a folded metal plate which had been embossed and gilded. Restoration of the object revealed that the folded plate was in fact the outer casing of a Roman copper alloy cavalry sports type helmet which dates to the late second or third century AD. The story of what became known as the Guisborough helmet began 14 years earlier in what was then the North Riding of Yorkshire when workers employed by the Cleveland Railway Company discovered a ‘very curious plate of metal’ during road construction. It appears that the helmet was deliberately prepared for deposition and buried at a depth of c30 cm close to a stream. Examination by the authors suggests that this was a high value item that had been repaired many times. Experimental evidence suggests that the decoration alone required approximately 16 h to fashion.     

COSMIC 掩星反演的水汽廓线质量分析

利用2006—2012年北半球冬季低纬度地区(30°S~30°N)无线电探空站数据及全球大气成分和气候监测再分析数据对1000 h Pa~200 h Pa高度层的气象、电离层与气候星座观测系统全球定位系统掩星反演的比湿廓线进行了精度和可靠性验证。结果表明,水汽对气象、电离层与气候星座观测系统掩星反演影响较大,尤其在中、低对流层及热带地区等水汽含量比较大的地区,且气象、电离层与气候星座观测系统掩星数据在850 hpa以下可能并不太适用于评估其他数据。     

From Nationalism to Factionalism: Faultlines in the Naga Insurgency

Do ceasefires or peace talks create fragmentation in the insurgent groups? Rather than proposing claims that can offer predictions about armed groups behaviour under ceasefires or peace processes, the analysts tend to focus largely on the dynamics between state and non-state actor. The experts pay little attention to overtime changes in social and local political context which might contribute to propelling a rebel group towards fragmentation and factionalism. The present study intends to fill this gap by exploring the shifting role of public opinion and ethnic support for the peace talks to ascertain whether it can increase the likelihood of factionalism in rebel groups or not. This article applies this approach to the case of Naga National Movement (1947–2015) in India, and finds that the proposed variable appears to have increased the frequency of factionalism in the movement.     

科学管理、精益管理与精确作战工程保障研究

设计是作战行动筹划的重要步骤,精确工程保障需要对工程保障行动进行精密的设计和精确管理与控制。科学管理采用科学实验的方法,通过劳动方法标准化和差别计件工资制度,有效提高了工作效率,其基本原理经过百余年的实际检验,被证明是一个成熟有效的管理方法。借鉴科学管理理论,需要对工程保障行动进行动作研究,进而研究工程保障行动的作业标准,以期提高其保障效率。精益管理是在科学管理在新的历史时期的发展与改进,它使用了准时制、零库存、均衡生产、持续改进等先进的管理理念和六西格玛管理、成组技术等先进技术,为基于信息系统体系作战的工程保障能力生成提供了有益的借鉴,可加深我们对精确工程保障的理解,促进精确工程保障研究的可操作性。     

悬臂式围护桩受力性状与内力传递特征试验

为研究悬臂式围护桩结构的内力、弯矩、位移和嵌固段的变化规律及特点,结合西宁火车站综合改造工程,对该深基坑支护结构在不同开挖工况条件下悬臂桩的受力性状与内力传递特征进行现场动态测试试验。试验结果表明:悬臂桩的受力特征与理论值有所差异,在实际设计中可对其在配筋方式、混凝土强度设计、嵌固段长度等方面进行优化。试验结果可以有效优化桩身设计,为复杂基坑在开挖过程中的支护结构受力及变形提供参考性依据。     

钢质管道挤压变形实验研究与结果分析

野外埋地敷设的长距离输油管道发生断裂等较大破坏时,采用管道局部挤压的方式,在较短时间内将管道快速压扁以截断流油。为了设计管道挤压截流装置,使用18 mm宽度的压头对?325 mm×6 mm的X60钢管进行挤压变形实验,得到了管道挤压的载荷-位移曲线、管道的变形范围、管道压扁后的回弹情况和挤压过程中的塑性载荷等数据,并验证了管道挤压过程中的安全性。通过实验,不仅可以研究管道塑性破坏后的变形规律,而且为管道泄漏抢修提供了理论和实践参考。     

Initiating insurgencies abroad: French plans to ‘chouannise’ Britain and Ireland, 1793–1798

Secret French plans to launch guerrilla-style raids on the British Isles devised in the spring of 1796 were referred to as ‘chouanneries’. The name and concept behind these small-war operations were modelled on the irregular tactics used by the Chouan rebels in the Vendée, which the French state army had brutally quashed, but some wished to transfer into their institutional practice. Part of France's ongoing military strategy in the war against Britain, which included fomenting insurrection in Ireland, these irregular operations were to be manned partially by pardoned deserters and released convicts and prisoners of war. Of these, only Tate's brief invasion of Wales in 1797 was realised, but the surviving plans provide insightful historical lessons into an Anglophobic mindset shared by a small network of practitioners and policy deciders on the effectiveness of such shock and awe tactics. Largely motivated by the desire to take revenge for Britain's support of counter-revolutionaries in the Vendée, these plans could more aptly be referred to as counter-‘chouanneries’.     

非相干背景光辐照二波耦合中的最佳匹配随机共振

针对非相干背景光辐照二波耦合中参数的最佳匹配设计问题,提出了一种基于随机共振理论的研究方法。首先,文章通过二波耦合过程进行物理机理分析和数值实验分析,证明了该问题在本质上可归结为一种随机共振现象。其次,从随机共振的角度,研究其中的最佳参数设计问题,给出了一种分布处理的最优参数设计流程。按照该方法,在给定增益要求的情况下,先根据信号光饱和与否来确定晶体长度,最后根据非相干光的比例对增益的影响来确定非相干光的比例。仿真实验表明,经过最佳参数设计后,信号的增益和输出信噪比上均有显著提高。