Si衬底上SrMnO3缓冲层对La0.8Sr0.2MnO3薄膜择优取向生长的影响

利用磁控溅射方法在(100)Si衬底上首先生长SrMnO3(SMO)作为缓冲层，再沉积得到了(110)择优取向生长的La08Sr02Mn03(LsMO)薄膜。利用X射线衍射仪分析了SMO缓冲层的结构特征对LSMO薄膜择优取向生长的影响。结果表明：当沉积温度为600℃时，增加缓冲层SMO的厚度，LSMO薄膜的取向性变好；当缓冲层SMO厚度为45nm时，LSMO薄膜基本具有(110)取向生长的特征。进一步的工作证实：提高沉积温度，能够显著增加SMO缓冲层的晶粒大小，并减少LSMO薄膜择优取向生长所需的缓冲层厚度；当沉积温度为800℃时，由于类退火作用的存在，厚度为10nm的SMO缓冲层就可以实现LSMO薄膜择优取向的生长。     

Electrical properties of Pb(Mg1/3Nb2/3)O3-PbTiO3 ceramics modified with WO3

Ferroelectrics 0.67Pb (Mg_1/3Nb_2/3)O₃-0.33PbTiO₃ (PMN-PT) + x mol% WO₃ (x=0.1, 0.5, 1, 2) were prepared by columbite precursor method. Electrical properties of WO₃-modified ferroelectrics were investigated. X-ray diffraction (XRD) was used to identify crystal structure, and pyrochlore phase were observed in 0.67Pb (Mg_1/3Nb_2/3)O₃-0.33PbTiO₃+2 mol% WO₃. Dielectric peak temperature decreased with WO₃ doping, indicating that W⁶⁺ incorporated into PMN-PT lattice. Lattice constant, pyrochlore phase and grain size contribute to the variation of K_max. Both piezoelectric constant (d₃₃) and electromechanical coupling factors (k_p) were enhanced by doping 0.1 mol% WO₃, which results from the introduction of “soft” characteristics into PMN-PT, while further WO₃ addition was detrimental. We consider that the two factors, introduction of “soft” characteristics and the formation of pyrochlore phase, appear to act together to cause the variation of piezoelectric properties of 0.67PMN-0.33PT ceramics doping with WO₃.     

电弧炉用替代废钢的金属炉料的进展

直接还原铁、铁水、冷生铁、脱碳粒铁、碳化铁、复合金属料等替代部分废钢作为电弧炉金属炉料，不仅可解决目前废钢供应短缺，也有利于稀释废钢中有害残余元素，提高钢的质量，是电弧炉冶炼优质钢的必要条件。文中介绍了电弧炉用各种金属炉料的特点和使用效果。     

Basic rules for rheologic forging process of semisolid alloy

Semisolid mold forging is a major type of semisolid processing, which is different from neither traditional mold forging nor traditional permanent casting. However, processing defects are often seen in work pieces because of lacking available rules for the process design and control. Some basic rules for the process design and control, simply named the shortest flowing length, pressure filling and the minimum uplifting mold pressure, are advanced in the paper based on amount of researches and experiments. The equations to determine the major process parameters are given out such as the filling pressure, forming pressure and locking mold pressure for the process design and control. The rules and equations are experimentally proved available and applicable by several actual work pieces produced by the semisolid forging process.     

战略成本管理的利器--业务外包

本文从分析业务外包的内涵开始入手 ,阐述了其对战略成本管理的意义 ,以及实施业务外包降低成本以获取竞争优势的主要途径     

现代工程建设项目信息化管理高效性研究

充分利用信息技术来提高工程项目管理水平，是现代工程建设项目发展的必然趋势，据此，通过论述现代工程建设项目信息化管理的特点和要求，初步阐述了建立工程项目信息化管理模式的方法以及这一模式所具有的功能，进一步分析了如何有效利用信息技术使其在项目管理中体现高效性。     

High-temperature single-crystal 3C-SiC capacitive pressure sensor

Single-crystal 3C-silicon carbide (SiC) capacitive pressure sensors are proposed for high-temperature sensing applications. The prototype device consists of an edge-clamped circular 3C-SiC diaphragm with a radius of 400 /spl mu/m and a thickness of 0.5 /spl mu/m suspended over a 2-/spl mu/m sealed cavity on a silicon substrate. The 3C-SiC film is grown epitaxially on a 100-mm diameter <100> silicon substrate by atmospheric pressure chemical vapor deposition. The fabricated sensor demonstrates a high-temperature sensing capability up to 400/spl deg/C, limited by the test setup. At 400/spl deg/C, the device achieves a linear characteristic response between 1100 and 1760 torr with a sensitivity of 7.7 fF/torr, a linearity of 2.1%, and a hysterisis of 3.7% with a sensing repeatability of 39 torr (52 mbar). A wide range of sensor specifications, such as linear ranges, sensitivities, and capacitance values, can be achieved by choosing the proper device geometrical parameters.     

Effect of Yttrium on Microstructures and Properties at Elevated Temperature of Mg-0.8Zr-0.35Zn Alloys

Asthelighteststructuralmetalmaterial ,themostobviousadvantagesofmagnesiumalloyaretheirhighspecificstrengthandspecificstiffness ,superdampingcapacityandmachinability ,excellentelectromagneticshieldingandnon toxicity .Theincreasingattentionhasbeenpaidonthepracticalapplicationofmagne siumalloysastheenergysavingandenvironmentpro tectionarebecomingtheworldfocus .However ,somedisadvantagessuchasignitableandcombustibledur ingmeltingandcastingandtheirrelativelypoorprop ertiesatelevatedtemperaturelimit…     

Micromagnetic Simulation of Magnetization Reversal in SmCo5／Sm2Co17 Magnets

A three-dimensional finite element micromagnetic algorithm was developed to study the magnetization reversal of the SmCo5/Sm2Co17 based magnets. The influences of the microstructure and magnetic parameters on the coercivity were studied based on the model consisting of 64 irregular cells according to the experimental microstructure. Numerical results show that the coercivity increases with increasing the 2: 17-type cell size. Large cell boundary thickness leads to small coercivity. The drop of anisotropy constant of 1:5 phase leads to the coercivity reducing, while the effect of exchange constant of 1 : 5 phase on coercivity is contrary to that of exchange constant. The calculated field dependence of coercivity can be predicted by an inhomogeneous domain - wall pinning model. The microstructure parameter was analyzed by comparing the calculated coercivity.     

Anomalous Magnetic Behavior in Phase-separated La0.5 Sr0.5 MnO3 +δ Films

(001)La0.5 Sr0.5MnO3 δ films on (001)LaA1O3 substrates were prepared by using a RF magnetron sputtering with powder target.At low temperature, the films exhibit two phase coexistence, which means that ferromagnetic (FM) clusters are embedded in antiferromagnetic (AFM) matrix.Moreover, a shift in hysteresis loop is unexpectedly observed in this inhomogeneous system.We suggest that the anomalous hysteresis loop may result from the unidirectional exchange anisotropy at the interface between AFM and FM clusters.