Relation of Single-Crystal Elastic Constants to Polycrystalline Isotropic Elastic Moduli of MgO: II, Temperature Dependence

The technical adiabatic elastic moduli E_[hkl] and G_hkl of single crystals of magnesium oxide were measured over the temperature range 298° to about 1600°K by a Förster-type resonance method. These data were compared with the low-temperature values (80° to 560°K) of the principal elastic constants c_ij and coefficients Sy reported by Durand. Combining Durand's data and the present data, the elastic moduli for single-crystal magnesium oxide were evaluated for the temperature range 80° to 1600°K. Young's modulus and the shear modulus of densely formed isotropic polycrystalline magnesium oxide were measured over the temperature range 298° to 1600°K. The data on the elastic constants of the single crystals were compared with the measured elastic moduli of the isotropic polycrystalline magnesium oxide on the basis of the Voigt-Reuss-Hill approximation. The temperature dependence of the elastic moduli was fitted into the expression M = M_c— BT exp (—T_c/T) suggested by Wachtman et al. ; mean deviations were less than 0.4% for the temperature range considered. The significance of the present data is discussed with particular emphasis on the following points: (1) the temperature variation of the elastic modulus is a function of thermal expansion, (2) the temperature dependence of the elastic modulus can be well described by the foregoing expression for a wide range of temperature, (3) the expression gives a value of the elastic modulus at 0°K, and (4) it may be possible to make use of measurements on the elastic properties of a densely sintered polycrystalline material to obtain information heretofore obtainable only from the corresponding single-crystal data.     

脉冲激光沉积制备的HT-LiCoO2薄膜中Li离子表观扩散的研究

采用脉冲激光沉积(PLD)方法在镀Pt的Si衬底上制备了LiCoO2薄膜,运用XRD、Raman光谱、SEM和循环伏安等方法对其结构与电化学性能进行表征,在此基础上着重采用电位间歇滴定技术(PITT)对其Li离子表观扩散进行了分析.结果表明,600 ℃制备的LiCoO2薄膜为HT-LiCoO2相,呈柱状晶结构,平均晶粒尺寸在100 nm以下,结晶度高,并且具有明显的[001]择优取向,但少量缺Li.伏安循环曲线表明,该LiCoO2薄膜具有良好的电化学可逆性,但只在3.9 V(vs Li/Li )附近出现一对氧化还原峰.PITT测试表明,PLD方法制备的HT-LiCoO2薄膜的Li离子扩散系数在10-8-10-9cm2/s,与其它方法(如射频磁控溅射)制备的HT-LiCoO2薄膜相比,扩散系数高1-2个数量级;并且PLD方法制备的HT-LiCoO2薄膜中Li离子扩散系数与相变有关,在两相共存区,由于相界钉扎的作用,Li离子扩散系数比其它区域小1-2个数量级.     

梯度孔隙率与大孔隙尺寸NiTi形状记忆合金的制备及其相变和超弹性行为

利用低温分解型造孔剂与梯级热等静压烧结和常规烧结的匹配工艺成功制备出了梯度孔隙率与大孔隙尺寸多孔NiTi形状记忆合金.多孔合金的孔隙率为30%-61%,孔隙平均尺寸可根据不同预处理工艺在50-500 μm之间变化,且具有较高的开孔率(最高可达85%).所制备的径向梯度孔隙率多孔NiTi合金具有良好的力学性能,线性超弹性应变大于4%;热分析和XRD分析表明,所制备的多孔合金呈现明显的马氏体转变和逆转变特征,相变特征温度随孔隙率的提高而降低.     

Selective catalytic NOx reduction on Antimony promoted V2O5-Sb/TiO2 catalyst

Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2.Several atoms were chosen as candidates and new catalysts were synthesized by impregnation method.The NOx conversion rate was measured at temperatures between 100 and 400 ℃ and poisoning effect was investigated.The most promising candidate promoter, Se, was excluded because of its high vapor pressure.On the other hand, Sb shows best promoting properties.Sb promoted catalyst reaches the maximum NOx conversion rate at 250 ℃.It also shows considerably enhanced resistance to poisoning of V2O5/TiO2 catalysts by SO2.     

Development of Independent Moving Puppet Robot

This paper is about the automation of the marionette performance.A method to solve the problem on the mobility of the automated marionette performance is proposed.Since it is difficult to control the marionette by hands,as an alternative,the automated marionette is studied.Hovever,the automatic marionette performance is limited in the silence and mobility.Therefore,an independent shifter to move freely on the stage is required.The magnetic device which connects the movable robot and the marionette controlling robot is conceived.The magnetic device is improved and applied by considering the features of the marionette robot,which is the irregular movement of the marionette controller and of the parallel limited area.The burden of being trapped on the magnet is minimized by dividing the robot to the upper and lower parts of the marionette performance stage.The direction of the magnet is considered to make the mobile robot to move freely.Thus,the efficiency and safety of the device is confirmed by balancing the strength with the permanent magnet.     

Separated Same Rectangle Feature for Face Detection

The paper proposes a new method of "Separated Same Rectangle Feature (SSRF)" for face detection.Generally,Haar-Like feature is used to make an Adaboost training algorithm with strong classifier.Haar-like feature is composed of two or more attached same rectangles,Inefficiency of the Haar-like feature often results from two or more attached same rectangles.But the proposed SSRF are composed of two separated same rectangles.So,it is very flexible and detailed.Therefore it creates more accuate strong classifier than Haar-Like feature.SSRF uses integral image to reduce executive time.Haar-Iike feature calculates the sum of intensities of pixels on two or more rectangles.But SSRF always calculates the sum of in-tensities of pixels on only two rectangles.The weak classifier of Ada-boost algorithm based on SSRF is faster than one based an Haar-likefeature.In the experiment,we use 1 000 face images and 1 000non-face images for Adaboost training.The proposed SSRF shows about 0,9% higher accuracy than Haar-Iike features.     

Design of Pipelined ADC Using Op Amp Sharing Technique

This paper presents a 10-bit 20 MS/s pipelined Analog-to-Digital Converter(ADC)using op amp sharing approach and removing Sample and Hold Amplifier(SHA)or SHA-less technique to reach the goal of low-power consumption.This design was fabricated in TSMC 0.18 μm 1P6M CMOS technology.Measurement results show at supply voltage of 1.8 V,a SFDR of 42.46 dB,a SNDR of 39.45 dB,an ENOB of 6.26,and a THD of 41.82 dB are at 1 MHz sinusoidal signal input.In addition,the DNL and INL are 1.4 LSB and 3.23 LSB respectively.The power consumption is 28.8 mW.The core area is 0.595 mm2 and the chip area including pads is 1.468 mm2.     

台北101大楼钢结构工程之施工监造(Ⅰ)

坐落于台北盆地软弱地质以及饱受地震、台风等天灾侵袭的“TAIPEI 101”成为了世界最高建筑物大楼的代名词,相较于海外超高层大楼的环境与条件。508m高的台北101大楼有着截然不同的困难与挑战。然而在众人的瞩目下。台北101大楼已昂首耸立于台北新天空,其整体工程亦已实质完工。“Bringing Taipci to The World”一直是业主团队期望打造的远大愿景,在国际观的思维考量下,安全、品质与专业分工为本工程最重要诉求,在“边设计、边施工”的模式下．业主一台北金融大楼股份有限公司选择了结合海内、外优秀国际团队进行联合承揽规划设计、监造管理与营建施工。在钢结构相关工程之施工与监造上,如特殊钢板规格以及相称焊材的研发与量产、巨型钢柱分节与吊运设备、巨柱制造电焊工法与过程控制、钢结构现场吊装与电焊品质控制、10,000psi（69MPa）之巨柱柱内灌浆规划与施工、429m高度的柱内灌浆验证与施工、裙楼80m跨距之造型屋顶构架制造与安装、5.5m直径及660t重之大型调质阻尼器质量块吊装与电焊、508m高度之塔尖顶升施工、331地震造成之损害与修护。以及配合多次施工中进行之大幅度补充设计及变更设计等等均为本工程艰困的施工特性。本公司有幸实质参与兴建台北101大楼之结构设计与结构监造工作长达七年时间,在所有团队的不懈努力下,台北101之结构工程终告圆满完成。本文旨在概要说明本工程钢结构工程之施工与监造之历程与结果,并佐以相关检讨与说明,期能供为学术界与工程界之参考。本文为第一部分。     

Economic analysis of inventory systems: a clarifying analysis

In a recent study by Gurnani (1983), ‘Economic analysis of inventory systems’, three main conclusions were presented. (1) The inventory models analysed in his paper demonstrate that the inventory policy derived from the discounted (PW) coat differs substantially from that given by the traditional undiscounted inventory analysis. (2) The difference between the two depends upon the discounting rate. The discounting causes the optimum order quantity and correspondingly the period length to vary monotonically with the discounting rate. (3) However, it is not influenced by the inventory system planning horizon. This paper first examines each conclusion and demonstrates why his conclusions are either unfounded or irrelevant to his analysis. Next, some crucial derivational errors in his exposition are demonstrated via corrected formulations. Finally, a net present value maximizing framework that is consistent with modern theory of financial analysis, is suggested for the economic analysis of inventory systems.