远距离沼气光测仪

<正> 美国矿业局研制出一种为煤矿井下远距离检测甲烷用的光学传感器(简称远距离甲烷光测仪)。这种光测仪可用于检测工作面的CH_4超限或检测井下难以进入区域和危险区域的 CH_4浓度。该光测仪还可装在行驶的矿车上用以检测风流中或顶板附近的甲烷层的甲烷浓度。本文阐述了光测仪样机在近红外线光谱区内根据微差吸收原理的工作情况。光测仪发射的光从一个远距离(12.2m 或更长)表面(如采煤工作面)反射回来,在两     

加拿大铁矿公司“求生存”的战略规划

加拿大拉布拉多和魁牝克省境内的加拿大铁矿公司(IOC)在世界上属特大型露天采矿联合企业。自从1981～1982年出现经济萧条以来,IOC公司为了在世界铁矿石市场上站稳脚跟,制定了一个全面降低费用和提高生产能力的规划。本文着重概述了降低各项费用使用的方法。     

露天矿用穿孔爆破法破碎岩石的研究

本文介绍了露天矿用穿孔爆破法破碎岩石的一系列研究。这些研究分为现场研究、计算机模拟和实验室试验。现场研究包括钻机和挖掘机监测、爆破震动观测和爆破过程的高速摄影。同时进行了炸药的爆压和爆速测量、破碎监测和块度分布的摄影分析。现场试验是在澳大利亚的煤矿和金属矿进行的。爆破的计算机模拟是用有限元模型进行的,以确定破碎程度和破碎块度的分布情况。对煤、铁矿石和锰矿石以及有关剥离物的试样进行了实验室试验,以确定断裂韧性和弹性模量等性能。对断裂韧性采用了四种不同的测量方法,其中包括今后选定作为标准试验法的V形切口试验。在爆破室也进行了模拟爆破,以验证爆破模型对破碎块度的预测。     

A UNIFIED TIME-MARCHING PROCEDURE FOR COMPRESSIBLE INCOMPRESSIBLE FLOWS

ＡＵＮＩＦＥＤＴＩＭＥ－ＭＡＲＣＨＩＮＧＰＲＯＣＥＤＵＲＥＦＯＲＣＯＭＰＲＥＳＳＩＢＬＥＩＮＣＯＭＰＲＥＳＳＩＢＬＥＦＬＯＷＳ￥ＣｈａｒｌｅｓＬ．Ｍｅｒｋｌｅ；ＦｅｎｇＪｉｎ－ｚｈａｎｇ（ＰｒｏｐｕｌｓｉｏｎＥｎｇｉｎｅｅｒｉｎｇＲｅｓｅａｒｃｈ，Ｔ...     

A Computational Model for Two—stage 4K—Pulse Tube Cooler：part I.Theoretical Model and Numerical Method

IntroduedonThe need for ctyogenic coOling of magnehcresonance imaging (MRI), superconduchng quantUminterfernce devices (SQUIDs) and the associatedsuperconduchng devices has brought about a strOngdemand for high reliability and efficiency in coolers.SWg and GM coolers, which are very compact andreliable machines and have already commercial products,are widely used for such aPplications in the last decades.However, they have a tnoving pistOn at the cold end,which caused evidenily mechotal …     

无铅钎料对波峰焊设备的影响

目前,无铅钎料应用的日益推广使得波峰焊设备问题更加突出.其中主要的问题是设备的腐蚀及材料的寿命.为此,许多设备制造商提出了不同的方案来解决此类问题.这些方案涉及范围从不对元件进行改进到使用昂贵的金替代整个钎料锅及喷嘴.本文对制造波峰焊设备"钎料元件"的所用材料进行评估.     

调制电子束在空间等离子体中激发的电磁波辐射

当调制电子束入射进空间等离子体时,由于电子束本征电磁场在非均匀等离子体中的散射(渡越辐射transition radiation)或者电子束的纵向约束性可以产生电磁波辐射.基于这两种辐射机制,研究了半无界调制电子束从航天器入射进平面分层各向同性非均匀空间等离子体产生的电磁波辐射.结果表明,由背景等离子体非均匀性产生的电磁波辐射强度高于由束的纵向约束性引起的辐射强度通过对电子束的适当调制,可以满足辐射电磁波在局部等离子体谐振区域的共振条件,从而增大辐射强度.研究结果可用于对主动空间等离子体试验数据的分析.     

Analysis of EMG and acceleration signals for quantifying the effects of deep brain stimulation in Parkinson's disease

Deep brain stimulation (DBS) is effective in reducing motor symptoms in Parkinson's disease (PD). However, objective methods for quantifying its efficacy are lacking. We present a principal component (PC)-based tracking method for quantifying the effects of DBS in PD by using electromyography (EMG) and acceleration measurements. Ten parameters capturing PD characteristic signal features were initially extracted from isometric EMG and acceleration recordings. Using a PC approach, the original parameters were transformed into a smaller number of PCs. Finally, the effects of DBS were quantified by examining the PCs in a low-dimensional feature space. The EMG and acceleration data from 13 PD patients with DBS ON and OFF, and 13 healthy age-matched controls were used for analysis. Clinical evaluation of patients showed that their motor symptoms were effectively reduced with DBS. The analysis results showed that the signal characteristics of 12 patients were more similar to those of the healthy controls with DBS ON than with DBS OFF. These observations indicate that the PC-based tracking method can be used to objectively quantify the effects of DBS on the neuromuscular function of PD patients. Further studies are suggested to estimate the clinical sensitivity of the method to different types of PD.     

强流金属离子注入

金属等离子体浸没注入（MEPIII）技术与金属蒸气真空弧（MEVVA）源注入技术有相同之处,也有各自不同的特点。采用两种方法进行钛离子注入硅,RBS方法分析注入层,并对两种注入技术予以比较。     

A Novel Approach for Redirecting Module in Honeypot Systems

1 Introduction Computer network security has been focus on passivedefense strategies usingtools and conceptslike Firewall ,Intrusion Detection System(IDS)[1 ~3]. This is an un-reasonable situation,because users have to protect com-puter systems perfectly, while hackers can use one ofvulnerabilities to attackthe systems . We are alwaysin apassive position.The bad guys have theinitiative .Theyhave unli mited resources and attack you whenever theywant , however they want . Moreover ,in a trad…