特柔软型钢丝铠装复合电缆设计探讨

本文主要探讨特柔软型钢丝铠装复合电缆的设计,根据特殊用户实际应用情况,设计出大拉力、超柔软钢丝铠装电缆,设计过程中不仅考虑电缆所应有的电性能,同时还要考虑电缆高强度抗张情况和应用中处于反复收放状态,而且所设计的电缆还要满足恶劣环境.     

城市地下管网管理系统数据分析

地下管线是城市基础设施的重要组成部分,是城市规划建设管理的重要基础信息。随着城市规模的扩大和现代化程度的不断提高,地下管线也越来越庞大、密集,其种类也越来越复杂,建立城市地下管网信息管理系统,实现地下管线信息的数字化管理工作,也是智慧城市建设的重要一环。文章从数据分类、地形数据来源与分析、地形数据分层、地形数据要求、管线数据要求等方面对地下管网管理系统涉及的数据进行了详细分析。     

SiN钝化前的NF3等离子体处理对AlGaN/GaN HEMT性能的影响

研究了SiN钝化前利用感应耦合等离子体(ICP)对AlGaN/GaN HEMT表面进行NF3等离子体处理对器件性能的影响.结果表明,运用低能量的NF3等离子体处理钝化前的AlGaN/GaN HEMT表面能有效抑制器件电流崩塌,而器件直流及微波小信号特性则未受影响.微波功率测试表明,经过6min NF3等离子体处理的AIGaN/GaN HEMT在2GHz,30V工作电压下达到6.15W/mm的输出功率密度,而未经过处理的器件只达到1.82W/mm的输出功率密度.     

Determination of the embedded electronic states at nanoscale interface via surface-sensitive photoemission spectroscopy

The fabrication of small-scale electronics usually involves the integration of different functional materials. The electronic states at the nanoscale interface ...     

基于可穿戴传感器数据的人体行为识别数据特征提取方法

随着可穿戴设备的发展与普及,基于可穿戴传感数据进行人体行为检测展现了巨大的研究价值.目前大多人类行为识别工作都是基于视频图像展开的,然而,使用计算机视觉技术进行人类行为识别存在2个挑战:一是很难使参与数据采集的人员在自然状态下采集真实状态下的运动数据,在开展数据采集之前往往需要对参与数据采集的人员进行培训并严格规范其采...     

不同围压下共面双裂隙脆性砂岩裂纹演化特性颗粒流模拟研究

岩体中含有大量节理、裂隙、断层等各类结构面,结构面在应力作用下的扩展与贯通是导致岩体破坏的重要原因。数值流形方法(NMM)可以有效模拟连续和非连续问题,然而,其在多裂纹动态扩展的模拟方面仍处于探索阶段。该文以线弹性断裂力学原理为基础,提出了一种基于高阶数值流形方法的多裂纹扩展模拟算法。通过在基函数中增加关键项来考虑裂纹尖端位移场的奇异性;裂纹尖端的应力强度因子则采用了J积分来计算;Ⅰ型-Ⅱ型混合裂纹的开裂和扩展方向依据最大周向拉应力准则来判断;采用假设-修正的多裂纹扩展算法解决了多裂纹的扩展问题。根据强化后的基函数,对于不符合单纯形积分形式的被积函数,采用了泰勒级数展开式计算近似解。通过多个静态裂纹扩展的经典问题的数值模拟对计算方法的合理性和计算精度及进行了验证。     

前桥下横臂加工工艺难点分析与解决

探讨分析了前桥下横臂在卧式加工心上试制的工艺难点,从建立坐标系、数铣内孔槽、螺纹加工等方面提出相应的解决方案．在实际加工过程中取得了良好的加工效果,对解决其它类似零件具有一定的借鉴意义。     

The Dependence of Energy Dissipation on the Elastic Energy Density of Friction Pairs in Hard Coating Films

The influence of different pairs on the energy dissipation of a given hard coating during fretting has been discussed. Based on the view of the competition between the elastic and plastic deformations in a fretting experiment, it suggests that the energy dissipation rate is proportional to the elastic energy density of pairs. This trend is in agreement with the reported experimental data. For comparison, hardness of pairs is used as the index to relate the antiwear properties of a DLC film against different pairs. It is obvious that the elastic energy density of pairs is more appropriate to predict the antiwear properties of the DLC film against different pairs.     

Strain sensing behavior of electrically conductive fibers under large deformation

Electrically conductive fiber/yarn/fabric is one of the promising materials as flexible conductive sensors because of their sensitivity to strain, temperature and humidity. Aiming at developing of effective flexible sensors, this study investigates experimentally the strain sensing behavior of PPy (polypyrrole)-coated Lycra fibers, showing that the electrically resistance of the conductive fibers changes with the deformation of fibers. The variation in electrically resistance is mainly related to the micro-cracks appearing on the fiber surface during deformation. Then, the effects of the characteristic parameters of the micro-cracks are studied statistically by means of image processing functions in MATLAB, and the governing parameters are determined. Based on the results, a model is built to describe the variation of electrical resistance by the parameters of the micro-cracks. The analytical results are compared with the experimental results, showing an acceptable agreement.     

Tooth flank modification theory of dual-torus double-enveloping hourglass worm drives

In this paper, the theory of tooth flank modification is enriched and developed for a double-enveloping toroidal worm drive. The goal and significance of the modification are expounded from the point of view of changing the tooth flank configuration for the worm gear pair. It is pointed out that the constant center distance modification, the constant transmission ratio modification, and the combination of the previous two are the convenient and reasonable modification strategies. All the corrected hourglass worm pairs, attained by employing the preceding modification methodology, can be divided into two fundamental types: the type I worm pair and the type II worm pair, from the perspective of the meshing behavior. The division criterion of the worm drive type is moreover provided on the basis of the value range of the modification parameters in this study. The meshing characteristics of the two types of the modified globoidal worm drive are summarized in detail. The results indicate that the type II worm gearing with slight modification should be the preferred style for the double-enveloping toroidal worm drive.