一种降低手臂疲劳的计算机键盘的设计

分析了标准键盘在使用时引起身体疲劳的因素,基于人机工程学的理论,提出了一种降低手臂疲劳的计算机键盘的设计方案。从键盘的整体布局、外形设计、按键的布置等方面提出具体的措施,以此提高键盘操作的舒适性,降低手臂疲劳,提高工作效率。     

无人驾驶飞机有望获得机械手臂和机械手

一般来说无人驾驶飞机(UAVs)依靠它们的机翼飞行,就像它们的地面表兄弟无人驾驶车辆(UGVs)通常依靠车轮行驶一样。但是来自德克塞尔大学工程学院的研究人员计划通过找出一种给这个航天器添加敏捷手和手臂的方式来改变这一现状。工程学教授、德克塞尔大学机械工程与力学部门负责人Paul Oh将会使用一笔来自美国国家科学基金会的拨款来进行在UAVs上应用机械手臂相关的扭矩和反作用力的试验。     

Call for Contributors to Fractography Handbook

Journal of Failure Analysis and Prevention -     

美国国防高级计划研究局（DARPA）登梯实验机器人获得手臂

当我们讨论能够行走和爬楼梯的军用机器人和人形机器人的时候,根据我们的报道,评论员们就已经推测出当军用人形机器人开始使用武器的时候会发生什么了。     

A Self-Powered Angle Sensor at Nanoradian-Resolution for Robotic Arms and Personalized Medicare

As the dominant component for precise motion measurement, angle sensors play a vital role in robotics, machine control, and personalized rehabilitation. Various forms of angle sensors have been developed and optimized over the past decades, but none of them would function without an electric power. Here, a highly sensitive triboelectric self-powered angle sensor (SPAS) exhibiting the highest resolution (2.03 nano-radian) after a comprehensive optimization is reported. In addition, the SPAS holds merits of light weight and thin thickness, which enables its extensive integrated applications with minimized energy consumption: a palletizing robotic arm equipped with the SPAS can precisely reproduce traditional Chinese calligraphy via angular data it collects. In addition, the SPAS can be assembled in a medicare brace to record the flexion/extension of joints, which may benefit personalized orthopedic recuperation. The SPAS paves a new approach for applications in the emerging fields of robotics, sensing, personalized medicare, and artificial intelligence.     

有限段法在自动武器多体动力学分析中的应用

自动武器发射过程是一个典型的刚柔耦合动力学过程.将有限段法引入自动武器多体动力学分析中,利用Timoshenko梁理论计算自动武器弹性构件的变形,提出了一种新的自动武器动力学分析思路.采用该方法建立了某型机枪11刚体29自由度的多体系统动力学模型,对机枪发射过程进行了数值仿真.计算结果表明该方法精度高、速度快,在自动武器动力学分析方面具有十分明显的优越性.     

简编轻武器的长期封存包装

介绍军队简编后轻武器长期封存包装的重要性.论证了包装长期封存的可能性,并对严格执行工艺要求及入库后的科学管理等方面提出了建议。     

防腐包装与武器装备

阐述了美国军队在海湾战争中使用高、尖、精武器装备充分发挥的巨大作用;以及当前国内、外因腐蚀所致的结果和影响;并且强调了今后应该重视的问题和需要加强的工作。     

武器维修器材的包装改革

概要论述武器维修器材所处的重要地位,分析维修器材包装存在的问题,探讨其改革需要考虑的问题,采取的技术途径,及其军事效益和经济效益,为我军装备现代化建设做出贡献。     

On the Materials Science of Nature's Arms Race

Biological material systems have evolved unique combinations of mechanical properties to fulfill their specific function through a series of ingenious designs. Seeking lessons from Nature by replicating the underlying principles of such biological materials offers new promise for creating unique combinations of properties in man‐made systems. One case in point is Nature's means of attack and defense. During the long‐term evolutionary “arms race,” naturally evolved weapons have achieved exceptional mechanical efficiency with a synergy of effective offense and persistence—two characteristics that often tend to be mutually exclusive in many synthetic systems—which may present a notable source of new materials science knowledge and inspiration. This review categorizes Nature's weapons into ten distinct groups, and discusses the unique structural and mechanical designs of each group by taking representative systems as examples. The approach described is to extract the common principles underlying such designs that could be translated into man‐made materials. Further, recent advances in replicating the design principles of natural weapons at differing lengthscales in artificial materials, devices and tools to tackle practical problems are revisited, and the challenges associated with biological and bioinspired materials research in terms of both processing and properties are discussed.     

A High Accuracy Self-Calibrating Bridge with Coupled Inductive Ratio Arms Used for Standard Inductors Comparison

A bridge with inductively coupled ratio arms based on a seven decade inductive voltage divider is described. It is used for mutual comparisons between the standard inductors which form the IEN reference bank of inductance. Provided some auxiliary balances are made, this bridge is able to measure its own residual inductances, both the inductances of the standard-to-bridge connections (about 2 ?H), made constant by the rigidity of the system geometry within a few nanohenries, and those of the variable resistance elements, also known within a few nanohenries. The self-calibrations are sufficiently accurate because the bridge has a high sensitivity even in comparisons of 1-?H inductors and in the use of ratios up to 1:100. Three variable resistance components are used to balance the bridge: a commercial box of 1-? steps, with calibrated inductance increments; a two-material helicoidal-motion wire resistor (0 to 1 ?), suitably designed with inductance variations less than ±1 nH; and a constant-geometry three-decade Kelvin-Varley divider, also designed for this specific purpose, with its total and partial inductance measured, and its total inductance kept constant within 1 nH. Where possible, connections between bridge components are realized by rigid tetra-axial conductors (4 coaxial tubular conductors). To avoid inductive coupling between the standards and the third tubular conductor, it is made of coated wires aligned along the generatrices of a cylinder. Provided the phase errors of the inductive voltage divider are known only within 1 ?rad, the bridge has an estimated ratio accuracy of ±[2.     

Call for Papers

Abstract

An expression is found for the propagation of the radiance function for light in any state of coherence through a concentrator which can be represented by a linear, stationary optical system. For light from a quasi-homogeneous source this expression can be somewhat simplified by an approximation. It is shown that the radiance function is invariant for a large class of optical systems. Finally it is shown that fundamental limitations for the concentration of light follow from the uncertainty principle and the second law of thermodynamics, which apply quite generally. These relations show why quasi-homogeneous light (i.e. light from thermal sources) cannot be concentrated as well as light from some other sources (such as light from a laser).