Effect of Substructure on the Thermoelectric Power of aβ-Quenched ZrCrFe Alloy

β-quenching a Zr-1.15 wt％Cr-0.10 wt％Fe alloy produces a martensitic or a Widmanst(a|¨)tten transforma-tion morphology,or a mixture of the two,depending on the cooling rate.For the Widmanst(a|¨)tten structure,orthe mixed martensitic-Widmanst(a|¨)itten structure,a grain boundary phase is observed at most prior-β grainboundaries.X-ray line broadening analysis and the thermoelectric power(TEP)measurements of thesequenched samples show that not only the solubility of alloying elements in α-Zr matrix,but also substructure(microstrain,crystallite size and dislocation density)have an effect on TEP.Thus,TEP measurements are verywell suited for following the structural transformations taking place in Zr alloys during fabrication.     

VELOCITY ANALYSIS OF A SPATIALM ECHANISM USING THE PRINCIPLEOF VIRTUAL FORCES

ＶＥＬＯＣＩＴＹＡＮＡＬＹＳＩＳＯＦＡＳＰＡＴＩＡＬＭＥＣＨＡＮＩＳＭＵＳＩＮＧＴＨＥＰＲＩＮＣＩＰＬＥＯＦＶＩＲＴＵＡＬＦＯＲＣＥＳＧｏｎｇＳｈｏｕｃｈｕｎ；ＤａｖｉｄＲｅｄｅｋｏｐＵｎｉｖｅｒｓｉｔｙｏｆＯｔｔａｗａ，Ｏｔｔａｗａ，Ｏｎｔａｒｉｏ...     

A NEW MINERAL——FLUORBRITHOLITE-(CE)

The new mineral fluorbritholite-(Ce)occurs innepheline syenite,marble xenoliths,sodalite syenite xenoliths andpegmatite dikes at Mont St.Hilaire,Quebec.It is associatedmainly with analcine,microcline,aegirine,zircon,biotite,Pyro-phanite,astrophylite,ancylite,natrolite,monazite etc.The mineral is hexagonal,P6_3/m,with a 9.517 (5) (?),c 6.983(4)(?),c/a 0.7337,v 547.7(8)(?),Z=2.The strongest Xray powder diffraction lines and their relative intensities(visual)are:2.851(100),2.821(30),2.753(30),1.970(20),1.969(30)(for MSH-3).Fluorbritholite-(Ce) crystal is shown prismatic.Its colouris pale yellow,tan,reddish-brown.Streak colourless to palebrown;Lustre adamantine;OPaque to translucent;Hardness 5;Brittle;Cleavage{0001}distinct;Fracture even to conchoidal;Density 4.66(1)(meas) or 4.66g/cm~3(calc.);Non-fluorscent.Optically umaxial(-),ω 1.792 (5),ε1.786(5) in Na light;Nonpleochroic.Electron microprobe analyses correspond to ((Ce_(1.69) La_(1.02)Na_(0.82) Nd_(0.44) Sr_(0.30) Ca_(0.17) Mn_(0.17) Y_(0.09) Pr_(0.06)     

隐通道存在的最小条件及其应用

隐通道能在安全机制的监控之下将保密信息外泄,因而对系统安全的威胁极大。通过研究隐通道的工作原理,形式化地证明了隐通道存在的最小条件。在此基础上,对现有的隐通道搜索与消除方法进行了分类,并从理论上说明了各种方法的正确性及其不足。这些工作不仅为隐通道的搜索与消除工作提供了可信的理论依据,而且为寻找新的隐通道搜索与消除方法提供了一个研究框架。     

兰加拉学院图书馆及教学楼

项目地点:加拿大温哥华项目类型:院校公共项目开工日期:2005年6月该项目获2005年豪瑞可持续建筑大奖赛北美地区提名奖     

Design of rock support system under rockburst condition

As mining and civil tunneling progresses to depth, excavation-induced seismicity and rockburst problems increase and cannot be prevented. As an important line of defense, ground control measures and burst-resistant rock support are used to prevent or minimize damage to excavations and thus to enhance workplace safety. Rock support in burst-prone ground differs from conventional rock support where controlling gravity-induced rockfalls and managing shallow zones of loose rock are the main target. Rock support in burst-prone ground needs to resist dynamic loads and large rock dilation due to violent rock failure. After reviewing the rockburst phenomenon, types of rockbursts, damage mechanisms, and rockburst support design principles and acceptability criteria, this paper describes that the support selection process in burst-prone ground is iterative, requiring design verification and modification based on field observations. An interactive design tool for conducting rockburst support design in underground tunnels is introduced to facilitate cost-effective design.     

VELOCITY ANALYSIS OF A PLANAR MECHANISM USING A METHOD FROM STATICS

ＶＥＬＯＣＩＴＹＡＮＡＬＹＳＩＳＯＦＡＰＬＡＮＡＲＭＥＣＨＡＮＩＳＭＵＳＩＮＧ　ＡＭＥＴＨＯＤＦＲＯＭＳＴＡＴＩＣＳＤａｖｉｄＲｅｄｅｋｏｐＧｏｎｇＳｈｏｕｃｈｕｎＵｎｉｖｅｒｓｉｔｙｏｆＯｔｔａｗａ，Ｏｔｔａｗａ，Ｏｎｔａｒｉｏ，ＣａｎａｄａＫＩＮ...     

(TiB2+Al2O3)增强铜基复合材料的研究

研究了Cu-Al-TiO2-B2O3粉末在机械合金化和随后的烧结过程中结构的变化，结果表明：Cu-Al-TiO2-B2O3粉末通过机械合金化可以形成Cu(Ti,B）及Al2O3和少量的TiCu3粉末，Al2O3是通过机械合金化过程中的自维持反应形成的，采用Cu,Al,TiO2和B2O3作为原料，通过机械合金化和随后的加压烧结，可以制备性能较好的（TiB2 Al2O3）增强铜基复合材料。     

用于铀-钍-铅地质年代学领域的几种分析方法

扼要介绍了当前用于铀-钍-铅地质年代学领域中的四种方法:(1)同位素稀释法;(2)SHRIMP离子探针法;(3)全颗锆石蒸发法;(4)~(210)Pb/~(206)Pb法。同时,对每种方法的优点及局限性作了评述。