基于Web的齿轮减速器设计优化系统开发

采用最新齿轮强度计算标准,利用ASP和网页制作技术,在Visual Basic、Visual Inter-Dev6.0环境下开发出了基于Web和齿轮设计制造专家咨询的减速器远程优化设计系统,从而实现减速器的远程优化设计,详细设计校核,齿轮的设计与制造的专家咨询,精度检索等。在减轻齿轮工程技术人员的劳动强度,提高工作效率,实现齿轮计算机辅助工程分析(CAE)等方面做出了一定的探索。     

Planning transport infrastructure: examining the politics of transport planning in Melbourne,Sydney and Perth

Abstract

Australian cities have observed a “consensus turn” expressed as broad public support of greater accessibility and public transport provision as revealed in metropolitan strategic plans. In contrast large-scale road projects proposed to traverse the inner-city of three major Australian cities reveals an ongoing and deep-seated attachment by some to car-based travel in Australian urban transport planning. Comparative case studies of these three road projects in Melbourne, Sydney and Perth explores the impact that an antagonistic relationship between the state and community has on the culture of transport planning. Through observational insights, policy and media analysis and interviews with community groups, we show that this antagonistic planning culture arises when there is a fracture between metropolitan strategic plan-making and project planning, and when clear channels of communication and deliberation are undermined.     

Simulation of long-range transport aerosols from the Asian Continent to Taiwan by a southward Asian high-pressure system

Aerosol is frequently transported by a southward high-pressure system from the Asian Continent to Taiwan and had been recorded a 100% increase in mass level compared to non-event days from 2002 to 2005. During this time period, PM2.5 sulfate was found to increase as high as 155% on event days as compared to non-event days. In this study, Asian emission estimations, Taiwan Emission Database System (TEDS), and meteorological simulation results from the fifth-generation Mesoscale Model (MM5) were used as inputs for the Community Multiscale Air Quality (CMAQ) model to simulate a long-range transport of PM2.5 event in a southward high-pressure system from the Asian Continent to Taiwan. The simulation on aerosol mass level and the associated aerosol components were found within a reasonable accuracy. During the transport process, the percentage of semi-volatile PM2.5 organic carbon in PM2.5 plume only slightly decreased from 22-24% in Shanghai to 21% near Taiwan. However, the percentage of PM2.5 nitrate in PM2.5 decreased from 16-25% to 1%. In contrast, the percentage of PM2.5 sulfate in PM2.5 increased from 16-19% to 35%. It is interesting to note that the percentage of PM2.5 ammonium and PM2.5 elemental carbon in PM2.5 remained nearly constant. Simulation results revealed that transported pollutants dominate the air quality in Taipei when the southward high-pressure system moved to Taiwan. Such condition demonstrates the dynamic chemical transformation of pollutants during the transport process from continental origin over the sea area and to the downwind land.     

浅谈新建本科院校化学类实验教学质量的保障

为确保化学类专业实验教学质量,实现新建本科院校培养高级应用型人才的培养目标,构建了一套化学类专业实验教学质量保障体系,并在实践中取得了良好的成效。     

Tunable excitation source for coherent Raman spectroscopy based on a single fiber laser

We demonstrate a wavelength tunable optical excitation source for coherent Raman scattering (CRS) spectroscopy based on a single femtosecond fiber laser. Electrically controlled wavelength tuning of Stokes optical pulses was achieved with soliton self frequency shift in an optical fiber, and linear frequency chirping was applied to both the pump and the Stokes waves to significantly improve the spectral resolution. The coherent anti-Stokes Raman scattering (CARS) spectrum of cyclohexane was measured and vibrational resonant Raman peaks separated by 70?cm(-1) were clearly resolved. Single laser-based tunable excitation may greatly simplify CRS measurements and extend the practicality of CRS microscopy.     

Analytical modeling of bidirectional multi‐channel IEEE 802.11 MAC protocols

This paper presents an analytical approach to model the bi‐directional multi‐channel IEEE 802.11 MAC protocols (Bi‐MCMAC) for ad hoc networks. Extensive simulation work has been done for the performance evaluation of IEEE 802.11 MAC protocols. Since simulation has several limitations, this work is primarily based on the analytical approach. The objective of this paper is to show analytically the performance advantages of Bi‐MCMAC protocol over the classical IEEE 802.11 MAC protocol. The distributed coordination function (DCF) mode of medium access control (MAC) is considered in the modeling. Two different channel scheduling strategies, namely, random channel selection and fastest channel first selection strategy are also presented in the presence of multiple channels with different transmission rates. M/G/1 queue is used to model the protocols, and stochastic reward nets (SRNs) are employed as a modeling technique as it readily captures the synchronization between events in the DCF mode of access. The average system throughput, mean delay, and server utilization of each MAC protocol are evaluated using the SRN formalism. We also validate our analytical model by comparison with simulation results. The results obtained through the analytical modeling approach illustrate the performance advantages of Bi‐MCMAC protocols with the fastest channel first scheduling strategy over the classical IEEE 802.11 protocol for TCP traffic in wireless ad hoc networks. Copyright © 2010 John Wiley & Sons, Ltd.     

基于相场模拟对镍基高温合金制备工艺优化及设计

材料制备过程中微结构演变的定量描述是材料设计的核心。近年来基于精准热力学和扩散动力学数据库的相场模拟是对微结构演变进行定量描述一种行之有效的方法。作为航空发动机和燃气涡轮叶片等高温零部件的主要用材,高性能镍基高温合金制备工艺的优化及设计一直是各国材料学者研究的热点和难点。首先概述了相场方法及其最新研究进展,以及相场法与CALPHAD(CALculation of PHAse Diagram)数据库耦合技术的发展,随后详细介绍了国内外有关镍基高温合金凝固、固溶及时效过程微结构演变定量相场模拟的报道,以及当前用于建立镍基高温合金微结构与力学性能关系的可行方法。之后给出了两个基于定量相场模拟对镍基高温合金固溶及时效热处理机制进行优化及设计的实例,进一步证明了相场模拟在高性能镍基高温合金设计中的重要作用。最后,指出了对镍基高温合金制备过程微结构演变进行定量相场模拟以及后续工艺优化和设计中存在的主要问题及发展趋势。