CX6112车铣复合机床设计方案的研究与探讨

文章较系统地论述了车铣复合机床设计方案的形成过程，同时分析了该设计方案的持点，并简要介绍了该产品的主要技术参数和用途，简评了该产品的技术水平。     

FFFIS编解码算法与实现

在对FFFIS(Form Fit Function Interface Specification)的Eurobalise报文特点进行简单介绍的基础上,对其编解码算法进行了探讨,并根据FFFIS标准提出了高速算法以及系统软硬件实现方案,最后对其应用进行了简单介绍。     

Microfabricated preconcentrator-focuser for a microscale gas chromatograph

The design, fabrication, and testing of a preconcentrator-focuser (PCF), consisting of a thick micromachined Si heater packed with a small quantity of a granular adsorbent material are described. The PCF is developed to capture and concentrate vapors for subsequent focused thermal desorption and analysis in a micro gas chromatograph. The microheater contains an array of high-aspect-ratio, etched-Si heating elements, 520 /spl mu/m (h)/spl times/50 /spl mu/m (w)/spl times/3000 /spl mu/m (l), bounded by an annulus of Si and thermally isolated from the remaining substrate by an air gap. This structure is sandwiched between Pyrex glass plates with inlet/outlet ports that accept capillary tubes for sample flow and is sealed by anodic bonding (bottom) and rapidly annealed glass/metal/Si solder bonding (top). The large microheater surface area allows for high adsorption capacity and efficient, uniform thermal desorption of vapors captured on the adsorbent within the structure. The adsorbent consists of roughly spherical granules, /spl sim/200 /spl mu/m in diameter, of a high-surface-area, graphitized carbon. Key design considerations, fabrication technologies, and results of performance tests are presented with an emphasis on the thermal desorption characteristics of several representative volatile organic compounds as a function of volumetric flow rates and heating rates. Preconcentration factors as high as 5600 and desorbed peak widths as narrow as 0.8 s are achieved from 0.25-L samples of benzene at modest heating rates. The effects of operating variables on sensitivity, chromatographic resolution, and detection limits are assessed. Testing of this PCF with a micromachined separation column and integrated sensor array is discussed briefly.     

工程机械和建材机械的盛大展会

德国慕尼黑国际博览集团是享誉全球的国际化大型博览公司,是世界上最重要的十大展览公司之一。自2002年始与上海新国际博览中心共同组织了两年一届的中国国际工程机械、建材机械、工程车辆及设备博览会(BAUMA CHINA)。2004年该博览会吸引了来自27个国家的738个参展商,展会场地达10万平方米,观众来自100个国家约5万多人(国外观众占21%)。鉴于中国使用工程机械、建材机械较多的交通运输业、建筑业、能源建设、水利水电建设等行业都保持了很高的发展速度,中国工程机械市场将是一个持续和不断成长的市场。2006年11月21—24日将在上海新国际…     

Reduction of triceps muscle force after shortening of the distal humerus: a computational model

A retrospective case reference study examining the use of alcohol and tobacco in 303 women aged 40 or over suffering from oral or oropharyngeal cancer was conducted in the south-west Netherlands. Both alcohol and tobacco consumption are important in the development of oral and oropharyngeal cancer with increased consumption of both markedly increasing the risks of cancer, but alcohol having the greater effect.     

Estimation and hypothesis testing of treatment effects in animal reproductive toxicology studies

Healy (1) and Dempster et al. (8) proposed statistical methods to evaluate the treatment effects in animal reproductive toxicology research. Both methods assume homogeneous variance for the dams and the pups, respectively, in all the treatment groups. In this paper, via mixed effect modeling, we propose a method to estimate the treatment effects allowing heterogeneous variances for the dams and the pups, respectively, in different treatment groups. Covariates will also be included in the model. A procedure to test the fixed effects is also discussed. An example from an animal reproductive toxicological study is used to illustrate the procedures.     

关系数据库在专家系统中的应用

在传统的专家系统中，对推理机工作过程的控制是程序实现的。本文介绍了一个用数据库技术引导推理过程的专家系统－精神分裂症诊断专家系统（ＥＳＳＤ）的推理控制策略。在这个专家系统中，作者将有关推理过程的控制信息用关系数据库技术进行存储和管理，达到了将控制策略数据化的目的。将数据库技术引入到专家系统的推进控制机制中可以使控制策略比较容易调整，且而可以大大压缩程序篇幅，显著提高系统运行效率，为专家系统的结构设     

Feasibility of adding a personal communications network to anexisting fixed-service microwave system

This paper examines the feasibility of adding a personal communication network (PCN) to a frequency band which is already allocated to fixed-service microwave systems. To achieve this goal, spread spectrum techniques are used to spread narrowband PCN signals into wideband. The forward and reverse link performance of PCN users under the influence of the microwave system and the influence of PCN users on the microwave system are both examined. It is proven that spectrum sharing between the PCN network and microwave systems is indeed feasible. Although our analysis is done based upon the consideration of only one microwave system, it can be easily extended to allow the appearance of two or more microwave systems     

立管系统中严重段塞流的一维瞬态模型

严重段塞流主要出现在下倾管段、紧接有一上倾管段或立管段的气、液两相混输海底管道中。根据严重段塞流形成的4个阶段,从一维瞬态流体力学方程出发,建立了一个简化的、准平衡态的严重段塞流数学模型,该模型考虑了流体的物性及流动瞬态效应,可对严重段塞长度、段塞周期、流动速度、压力等特性参数的变化进行模拟。与其他瞬态多相流模型相比,本文模型具有数学模型简单、计算效率高的特点。数值模拟结果表明:当管径较小时,无论介质是空气和水,还是空气和油,由本文模型计算得到的段塞周期和压力结果都与实验数据吻合较好;当管径较大时,若介质为空气和水,则本文模型计算结果与OLGA软件模拟结果较接近;若介质为石油和天然气,在模拟工况范围内,除了小气量工况下偏差较大外,本文模型计算结果与OLGA软件模拟结果相比,段塞周期偏差在25%以内,压力偏差在10%以内;此外,用本文模型计算液塞生长阶段时间t1比Saga-tun模型模拟结果更接近实测结果。