MICROSTRUCTURE AND MECHANICAL BEHAVIOUR OF Al-Li-Zr AND Al-Li-Cu-Mg-Zr ALLOYS

The aging response,tensile and impact properties of two kinds of Al-Li based alloys havebeen studied.The microstructure,deformation as well as fracture behaviour in the alloys wereobserved with SEM and TEM.It was found that the mechanisms of deformation and fracturefor different heat-treated alloys with the same chemical composition are quite different.Thecauses leading to the drop of ductility,toughness as well as anisotropy in peak-aged alloyshave been analysed.Finally,possible methods to improve the ductility and toughness of the al-loys have been discussed.     

Er-Doped LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript>

LiMn_2-x Er_xO₄ (x ≤ 0.02) materials were synthesized by a rheological phase reaction method. The thermal behavior of the materials was examined by thermogravimetric and differential scanning calorimetry. X-ray diffraction showed that the samples (x ≤ 0.02 ) exhibited the same phase as the pure spinel. The lattice parameter of the Er-doped spinel was smaller than that of the undoped one and decreased with increasing doping level. Cyclic voltammograms showed two reversible processes corresponding to the typical response of spinel LiMn₂O₄ and revealed an insertion-extraction reaction occurring at two stages in the 4-V region. The electrochemical performances of the samples were studied and displayed a better reversibility and cyclability.__________From Neorganicheskie Materialy, Vol. 41, No. 6, 2005, pp. 740–743.Original English Text Copyright © 2005 by Haowen Liu, Li Song, Kelli Zhang.This article was submitted by the authors in English.     

中国海绵城市——一座巨型绿色屋顶实验室

绿色屋顶是雨洪管理中一项重要的低影响开发（LID）措施。由于气候变化和城市快速发展,LID雨洪管理策略对于当下全球的城市设计都至关重要,尤其是在经济蓬勃发展历来又饱受洪水灾害的中国。气候变化导致降水事件及雨水径流峰值流速难以准确预测。面对建筑布局日益稠密、不透水下垫面日益增多的中国城市,设计师们需要随时做好应对城市雨洪问题的准备。2015年提出的“海绵城市”战略为在城市尺度下应用和监测绿色屋顶效益提供了机会。目前业内大多数国际性绿色屋顶的研究应用都局限于小型控制实验区,借海绵城市建设之东风有机会将应用实验扩展到城市规模。中国雨洪管理智慧的历史可以追溯至5 000年前,现今中国正处于成为大尺度绿色屋顶实践世界领先者的机遇期。因此,LID应是城市设计的驱动力量而非事后补救措施。景观设计师不仅能够从场地、城市和区域3个层面上对场地及其周围环境进行全面解读,而且对需要实施LID的其他因素也有全面认知。为探究中国雨洪管理结构提供了新的视角,对景观设计师如何参与LID实践提出了建议。     

MODELLING OF MICROSTRUCTURE EVOLUTION AND PROPERTIES OF LOW-CARBON STEELS

1.IntroductionMicrostructureprocessmodelsareincreasinglyonhotstriprollingofste.l[1--7].Thesemodelsfrequentlyincorporateagreatdealofempiricismwithcomparativelytightprocessrangesofapplicability.Morefundamentallybasedprocessmodelsarerequiredtodeveloppredictivetoolstooptimizetheproductionforawiderangeofmilldesignsandprocessingconditions.Theprocessofhotstriprollingoflow--carbonsteelscanbesubdividedintothreeprin-cipalstages:(i)reheating,(n)rollingand(iii)cooling(watercoolingontherun--outtableandsubs…     

Multi-objective Topology Optimization of Thermo-mechanical Compliant Mechanisms

The material characteristics of a structure will change with temperature variation,and will induce stress within the structure.Currently,the optimal design for the topology of compliant mechanisms is mainly performed in single physical field.However,when compliant mechanisms work in high temperature environments,their displacement outputs are generated not only by mechanical load,but also by the temperature variation which may become the prominent factor.Therefore,the influence of temperature must be considered in the design.In this paper,a novel optimization method for multi-objective topology of thermo-mechanical compliant mechanisms is presented.First,the thermal field is analyzed with finite-element method,where the thermal strain is taken into account in the constitutive relation,and the equivalent nodal thermal load is derived with the principle of virtual work.Then the thermal load is converted into physical loads in elastic field,and the control equation of the thermo-mechanical compliant mechanism is obtained.Second,the mathematical model of the multi-objective topology optimization is built by incorporating both the flexibility and stiffness.Meanwhile,the coupling sensitivity function and the sensitivity analysis equations of thermal steady-state response are derived.Finally,optimality criteria algorithm is employed to obtain numerical solution of the multi-objective topology optimization.Numerical examples show that the compliant mechanisms have better performance and are more applicable if the temperature effect is taken into account in the design process.The presented modeling and analysis methods provide a new idea and an effective approach to topology optimization of compliant mechanisms in electrothermic coupling field and multiphysics fields.     

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)     

High-basicity determination in mixed water-alcohol solutions by a dual optical sensor approach

The activity of NaOH is known to be significantly affected by the presence of an alcohol in aqueous solutions. A novel linear relationship between (deltaA/deltaC(alcohol)) and C(base) was found in the highly alkaline, mixed H2O-ROH solutions (R = Me, Et, i-Pr). The use of this linear relationship led to a dual-transducer approach to decompose the optical signals of optical base sensors and to give base and alcohol concentrations in concentrated NaOH-H2O-ROH solutions ([OH-] = 0.05-3.6 M). The scope of the new dual-sensor approach was evaluated, and errors in C(base) and C(alcohol) were analyzed. The optical base sensors consist of sol-gel SiO2-ZrO2-organic polymer composites doped with high-pKa indicators. The pKa(s) of the indicators encapsulated in the composite films were determined and found to be affected by the composition of the sol-gel composites. Optical sensors and their uses in multicomponent systems are of intense current interest.( 1-7) In the multicomponent systems, the activity of the analyte and sensor response are often affected by change in ionic strength. For optical sensors that are based on indicator equilibria involving the analyte as their transducing mechanism, such effect is particularly significant. The concentrations of both the analyte and other chemicals affect ionic strength, and the sensor response to concentration of the analyte is thus often indistinguishable from those of other chemicals. An accurate measurement of each component in these multicomponent systems is actively studied. Several approaches have been developed to correct ionic strength in optical sensing for the pH region and solutions of low-to-medium ionic strength. (1-9) We recently reported a dual-transducer approach to measure acid concentrations (2-9 M HCl) in salt-containing, concentrated strong acids such as MClx-HCl (M = Li, Ca, Al) solutions. (10) This approach was shown to reduce the error in C(acid) from, for example,     

Binge-drinking-related consequences in college students: Role of drinking beliefs and mother–teen communications.

The present research contrasted theoretical models depicting the nature of the relation among drinking beliefs, drinking tendencies, and behavioral consequences in 266 incoming freshman college students. It also examined the theoretical relations between mother–teen communications and drinking beliefs relevant to behavioral consequences. The findings revealed direct relations between binge-drinking consequences and the drinking beliefs: Alcohol can make positive transformations, can enhance social behavior, and can increase negative affect and normative approval. Direct relations were not observed between consequences and the drinking beliefs regarding physical risk and health orientation. Finally, the present research found consistent support for the relation between mother–teen communications and drinking beliefs relevant to binge-drinking consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

散热器和低温水辐射采暖系统不同连接方式及控制策略动态仿真

散热器和低温水辐射采暖系统最佳连接方式一直是业界探讨的重要课题之一。本文以动态模型为手段,模拟和分析直接、混水泵及间接连接方式系统动态响应和能耗。仿真结果表明,地板热情性的提高延长了室内温度达到稳态时间;地暖系统直接连接方式是不适宜的;混水泵和间接连接系统可节省燃料消耗约17％。从控制角度看,间接连接系统具有更好的稳定性和控制精度。     

SHIRAZ: an automated histology image annotation system for zebrafish phenomics

Histological characterization is used in clinical and research contexts as a highly sensitive method for detecting the morphological features of disease and abnormal gene function. Histology has recently been accepted as a phenotyping method for the forthcoming Zebrafish Phenome Project, a large-scale community effort to characterize the morphological, physiological, and behavioral phenotypes resulting from the mutations in all known genes in the zebrafish genome. In support of this project, we present a novel content-based image retrieval system for the automated annotation of images containing histological abnormalities in the developing eye of the larval zebrafish.