Performance evaluation of a dental handpiece in simulation of clinical finishing using a novel 2DOF in vitro apparatus

This paper reports on the performance evaluation of a dental handpiece in simulation of clinical finishing using a novel two-degrees-of-freedom (2DOF) in vitro apparatus. The instrumented apparatus consisted of a two-dimensional computer-controlled coordinate worktable carrying a dental handpiece, a piezoelectric force dynamometer, and a high-speed data acquisition and signal conditioning system for simulating the clinical operations and monitoring the dental finishing processes. The performance of the dental handpiece was experimentally evaluated with respect to rotational speed, torque, and specific finishing energy under the applied clinical finishing conditions. The results show that the rotational speeds of the dental handpiece decreased by increasing either the depth of cut or the feed rate at a constant clinically applied air pressure and water flowrate. They also decreased when increasing both the tangential and normal finishing forces. The specific finishing energy decreased with an increase in either depth of cut or feed rate, while the finishing torque increased as either the depth of cut or the feed rate was increased. Implications of these results were to provide guidance for proper applications of dental handpieces in clinical practice.     

基于Windows Media的网络媒体服务系统的实现

介绍了Windows Media系统的体系结构和通信协议,构建了采用Windows Media技术的网络媒体服务系统,详细叙述了系统的连接、配置和技术要点,以较低的代价实现了媒体服务系统的应用。     

Direct manipulation of FFD: efficient explicit solutions and decomposible multiple point constraints

Published online: 25 July 2001     

ProxyServer中Cache的管理和使用

使用Ｃａｃｈｅ可以减少Ｂｒｏｗｅｒ的等待时间和降低代理服务器和Ｉｎｔｅｒｎｅｔ的通信量,本文主要介绍了Ｐｒｏｘｙ对Ｃａｃｈｅ管理和使用。     

1000BASE—T—在5类铜缆上实现千兆传输

１０００ＢＡＳＥ－Ｔ是一种在５类铜缆上传输１０００Ｍｂｐｓ速度的以太网解决方案。本文介绍了１０００ＢＡＳＥ－Ｔ的基本特性、关键性能参数及其设计。     

Polycrystalline diamond MESFETs by Au-mask technology for RF applications

Metal-semiconductor field effect transistors (MESFETs) were fabricated on H-terminated polycrystalline diamond.The DC characteristics of the p-channel MESFET showed a maximum drain current density of 204 mA/mm at a gate-source voltage of 6 V,and a maximum transconductance of 20 mS/mm at a gate-source voltage of 1.5 V.The small signal S-parameters of MESFET with 2 100 m gate width and 2 m gate length were measured.An extrinsic cut-off frequency (fT) of 1.7 GHz and the maximum oscillation frequency (fmax) of 2.5 GHz were obtained,which was the first report on diamond MESFETs with RF characteristics in China.     

Node trust evaluation in mobile ad hoc networks based on multi-dimensional fuzzy and Markov SCGM(1, 1) model

Due to the nature of distribution and self-organization, mobile ad hoc networks rely on cooperation between nodes to transfer information. One of the key factors to ensure high communication quality is an efficient assessment scheme for risks and trust of choosing next potential cooperative nodes. Trust model, an abstract psychological cognitive process, is one of the most complex concepts in social relationships, involving factors such as assumptions, expectations and behaviors. All of the above make it difficult to quantify and forecast trust accurately. In this paper, based on the theories of fuzzy recognition with feedback, SCGM(1, 1) model and Markov chain, we present a pattern of prediction making. The analysis and experimental computation show that this scheme is efficient in trust prediction for ad hoc networks.