Inverse Perturbation Method for Inverse Eigenvalue Problem Based on Finite Element Analysis

An inverse perturbation method is described for solving the general inverse eigenvalne problem. By taking the analysis of the rotor system as example based upon FEM,the new inverse perturbation method for structural design with specified low-order natural freqneneies or frequency constraint bands is detailed as well as its complete theoretical basis. Moreover, formulations to calculate the inverse perturbation parameter ε and method to select thecorresponding ε‘s value properly are also proposed. Theproposed method is characterized in reducing frequencyanalysis and suitable for large and small structural changesalike. Finally, several different numerical examples forinverse eigenvalue problem are discussed to illustrate themethod, which show that this inverse perturbation methotis general and can be applied to other type of structure orelement.     

机器人腕部力传感器的标定

力反馈是机器人控制技术中一种重要的反馈。位于机器人手臂和夹持器之间的腕部力传感器是最重要的力传感器。对力传感器进行标定就是找出其标定矩阵。作者提出了求标定矩阵的方法,并指出Shimino和美国机器人技术公司——RTI的标定方法是错误的。专门设计的实验表明,用作者提出的方法所得的标定矩阵进行计算,测定载荷与实际施加的载荷是相接近的,而RTI公司的结果与施加载荷相差甚大。作者还提出了一种简化的6×6标定矩阵,用其计算的结果也与实际施加载荷接近。     

全球纳米技术研究文献计量分析

本研究采用文本挖掘技术，从在全球公开的纳米科学和技术研究文献数据库（SCI/SSCI 数据
库）中提取技术情报。在SCI/SSCI数据库中利用纳米科学和技术领域的300多个术语进行相关文献的检
索；利用摘要共现词汇的自相关图来揭示的技术核心领域；通过词汇间的互相关图来揭示因共现而发生
关系的词汇的技术核心领域；采用因子矩阵进一步量化研究机构之间、国家之间的关系强度，并对图中
揭示的合作出版网络给予确证。     

可逆循环伏安法电流函数的一种新算法

提出可逆过程循环伏安曲线的积分形式精确解,用Gauss-Legendre 求积公式解出正反向循环伏安曲线,讨论各种因素对伏安曲线、峰电流、峰电位的影响。同时对某些用于半积分电流公式验算。     

陶瓷超塑性综述

现已公认超塑性是陶瓷中一种很有潜力的变形工艺.本文总结了陶瓷及其它非金属材料中超型性的主要特点并考察了这些材料中相变与组织两种超塑性的报导.结果表明其与金属既有相同又有不同之处.相同的是应变速率随应力及晶粒尺寸的变化,重要的区别是必须考虑到陶瓷中的晶间非晶相的作用.在金属间化合物及地质材料中超塑性同样也是重要的,在地质材料中无论在试验室试验或自然界的变形中部有超塑变形的迹象.     

Filtered Backprojection Reconstruction with Depth-Dependent Filtering

A direct filtered-backprojection(FBP) reconstruction algorithm is presented for circular cone-beam computed tomography(CB-CT) that allows the filter operation to be applied efficiently with shift-variant band-pass characteristics on the kernel function.Our algorithm is derived from the ramp-filter based FBP method of Feldkamp et al.and obtained by decomposing the ramp filtering into a convolution involving the Hilbert kernel(global operation) and a subsequent differentiation operation(local operation).The d...     

微纳系统中的可持续自供型电源: 能源研究中的新兴领域

自从手提电脑和手机等个人可移动电子产品普及以后, 解决小范围的用电显得格外重要. 我们目前主要靠的是蓄电池. 在未来不久, 由于微纳系统的发展以及它们在原位人体健康的实时监测、基础设施的监测、环境监测、物联网以及军事技术上的应用, 传统的利用蓄电池来提供电源的方法将不能满足或不能适应传感器网络的工作环境和要求. 在2005年, 作者提出了自驱动的概念, 其根本是利用从环境中收集的能量, 通过能量转换来驱动这些微纳系统, 实现功率自给. 本文介绍作为微纳系统中可持续自供型电源的一种——纳米发电机的研究和未来应用.     

Design and Analysis of Prioritized Medium Access Control Protocol for Backbone Routers in Wireless Mesh Networks

A Prioritized Medium Access Control (P-MAC) protocol is proposed for wireless routers of mesh networks with quality-of-service provisioning. The simple yet effective design of P-MAC offers strict service differentiation for prioritized packets. A Markov model is developed to yield important performance matrices including the packet blocking probability due to queue overflow and the packet reneging probability due to delay bound. It is further proved that the service time of P-MAC approximates exponential distribution, and can be effectively estimated. The analytic models with preemptive and non-preemptive schemes, validated via simulations, show that P-MAC can effectively support traffic differentiation and achieve very low packet dropping (both reneging and blocking) probabilities when the traffic load is below the channel capacity. When the network is overloaded, P-MAC can still maintain extremely stable and high channel throughput. Moreover, it is demonstrated that P-MAC performs superior in multihop networks, further proving the advantages of the proposed protocol.     

面向公共机构与私营企业之间知识转移的组织行为与人力资源管理：文献分析综述（1）

基于人力资源视角对目前有关高校与私营企业之间知识转移渠道的学术研究成果予以述评,给出了文献分析的一般框架,明确了在面向高校一企业知识转移的组织行为和人力资源管理方面的认识缺陷。分析表明：具有最高“关系强度”的知识转移渠道最受企业重视,而大多数知识转移渠道目前并未制度化和正规化。结论认为,在高校．企业的知识转移方面存在显著的管理挑战,这要求对个体参与知识转移的性质和程度有深入的了解。但是,现有研究关注的重点在于知识转移的结果而非过程,因此,未来研究需要重视对个人和组织层面知识转移过程的分析,从而为更优决策的制定提供有价值的信息。     

Physical Characteristics of Knitted Polyester Vascular Prostheses： Can the Wall Be Considered as a Scaffold for Tissue Regeneration？

Recent developments in endovascular surgery (EVAR) have opened new avenues to successfully treat aneurysms with percutaneous deployment of stent-grafts.Manufacturers have preferred to use woven fabrics or micro-porous tubes which are supported by metallic frames or stents.Woven fabrics are much thinner than knits and this permits the use of a smaller delivery catheter.However,since woven constructions are stiffer and have little porosity,the tissue ingrowth is poor or absent.On the other hand,knitted constructions can be considered as a scaffold for tissue ingrowth,and hence they represent an attractive alternative because of their open structure and better conformability in the case of balloon deployment.The present study was undertaken to analyze the properties of two knitted and crimped polyester arterial prototype prostheses,one with and the other without a gelatin coating as sealant.Two commercial controls were also included in the study,namely the uncoated knitted polyester vascular prosthesis VP1200K,and its sealed version,the gelatin coated polyester knitted Gelsoft device,manufactured by Vascutek Ltd.,Scotland,UK.In vitro testing consisted of analyzing the geometry and morphology of the yarn and fabric structures,and measuring the physical and mechanical properties of the grafts,including the water permeability,the longitudinal and radial compliance,and the suture retention strength.In order to compare the different properties of the four samples,tests were also performed on the gelatin coated or sealed devices before and after gelatin removal.The results provided a useful comparison between the prototypes and the commercial control devices.The latter used ten times the amount of gelatin which had been applied as a coating in order to achieve the same low level of impermeability to water.The different amounts of gelatin also explained the different mechanical performance,such as compliance,for these prototype and control prostheses.