Finite element damage analysis of an underwater glider–ship collision

Underwater gliders, which are profiling autonomous underwater vehicles designed to make oceanographic measurements, are increasingly used in the coastal ocean. As they regularly surface for data transmission, gliders increasingly pose a risk for fast ships. In order to estimate the extent of damage due to collision, 3D finite element simulations of collisions between a glider and a high-speed craft with a glass-fiber reinforced plastic hull are performed. Different collision scenarios such as impact locations, angles of attack and speeds are examined. The results are compared to an analytical solution based on simplifying assumptions. Although both methods reveal consistent results, it is shown that finite element simulations are required to account for the 3D shape of the ship. The results indicate that at ship velocities exceeding 7.5 m/s (14.6 kt) the glider penetrates the ship’s hull causing severe damage to its structure.     

带式电动助力转向：让转向更精确 操控感更真实

对零部件供应商来说，电动助力转向（EPS）的技术挑战在于，如何达到并超越液压系统的操控感。最新的EPS技术--带式驱动EPS，尤其适用于前桥重量较大的车型，能够满足所有汽车细分市场对转向系统的高要求。     

防伪技术

品牌保护计划和产品供应链项目的成功与否，取决于品牌供应商是否有能力满足不同客户的个性化需求。现在，造假技术已经非常高明了，假冒伪劣产品完全可以达到以假乱真的程度，人们从外包装上很难区分出假冒伪劣产品与正品的差异。采用科学方法设计的防伪包装技术能够确保药品的真实性、质量和安全性。     

Two-Dimensional Contact Area of a Pneumatic Tire Subjected to a Lateral Force

A mathematical model of a two-dimensional contact patch of pneumatic tires rolling over a rigid flat road surface at arbitrary slip and camber angles has been developed. The model is simple in concept, contains few parameters and is applicable to any tire simulation models. In addition to tire geometric parameters and vertical deflection, the carcass camber angle is introduced in the model. This angle is alone responsible for the asymmetric shape of the tire contact patch when the tire undergoes a lateral force. The computed contact patches agree well with the measured patches of an automotive tire at different slip and camber angles. Lastly, the influence of the contact patch geometry on the tire cornering and aligning properties has been discussed through a computational example. It has been shown that the effect of tire contact patch geometry on the steady state behavior is rather remarkable.     

整合医疗经验

在推进转译医学的进程中，生物制药研究与医疗保健诊断之间的联系将更加紧密，并从中受益良多。研究人员必须能够获得并使用大量通过临床试验和医疗实践收集的信息。特别是对于某些跨学科领域而言，例如系统生物学、生物标记研究和个，性化用药方面，这些信息更是必不可少的。     

评《东南亚港埠与政体之兴衰》

<正>本书收录的12篇论文,系20世纪80年代初由东南亚英国学院资助召开的两次学术研讨会的研究成果,令人耳目一新。这些文章对东南亚部分重要地区从古代至19世纪末的贸易与政体之间的相互关系进行了选择性的探讨。不过,书中绝大部分的论文讨论的是1400年之后的情况,当时,贸易的迅速增长限制了该地区传统权力的变动。书中仅有一篇有关阿瑜陀耶(Ayutthaya)的文章考察了东南亚大陆的非马来地区。     

Vertical Load-Deflection Behaviour of a Pneumatic Tire Subjected to Slip and Camber Angles

In this paper the vertical load-deflection behaviour of a pneumatic tire has been studied theoretically. A simple mathematical model which is especially suitable for a tire applied by a side force has been developed. Researches carried out in the past show that the tire vertical stiffness varies neither proportionally nor symmetrically as the slip angle of a cambered tire is changed. This effect can be explained by the theory developed here.

The model predictions have been verified using experimental results obtained from literature. Moreover, tire cornering characteristic curves obtained under different test conditions, i. e. during increasing of the slip angle the vertical load is kept constant or not, have been discussed through a simulation example. This study shows that the characteristic curves vary rather considerably under the different conditions.