Morphology study of oriented SmBCO film deposited by MOCVD

c-axis-oriented SmBa_2Cu_3O_7(SmBCO) films have been deposited on(100)- LaA1O_3(LAO)substrate by metal organic chemical vapor deposition(MOCVD) technique.The effects of deposition temperature(T_(dep)) and total pressure(P_(tot)) on the orientation and microstructure of SmBCO films were investigated.The orientation of SmBCO films transformed from α-axis to c-axis with increasing of T_(dep) from 900 to 1 100℃.At T_(dep)=1 050℃,SmBCO films had c-axis orientation and tetragon surface.At P_(tot)~(dep)=400-800 Pa and T_(dep)=1 050 ℃,totally c-axis-oriented SmBCO films were obtained.The R_(dep) of SmBCO films increased firstly and then decreased with increasing P_(tot).The surface of SmBCO films exhibited tetragon morphology at 1 050 ℃ and400 Pa.Maximum thickness of SmBCO film deposited was 1.2μm at P_(tot)= 600 Pa,and the corresponding R_(dep)was 7.2 μm·h~(-1).     

Annealing effects on the structure and hardness of helium-irradiated Cr2AlC thin films

Cr₂AlC MAX phase thin films prepared by radio-frequency magnetron sputtering were irradiated at room temperature by 100 keV helium ions to a fluence of 1 × 10¹⁷ ions cm⁻². The effects of thermal annealing on the structural and mechanical properties of the helium-irradiated Cr₂AlC films as well as the helium release were investigated by grazing-incidence X-ray diffraction (GIXRD), Raman spectroscopy, and scanning electron microscope (SEM) in combination with nano-indentation and elastic recoil detection (ERD) analysis. The irradiation-induced structural damage in the Cr₂AlC is significantly recovered by thermal annealing at temperatures around 600℃, attributed to high defect diffusivity. After annealing to 750℃, the hardness of irradiated films recovered almost completely, which is ascribes to both defect recombination and reformation of damaged chemical bonds. Substantial helium release occurring at this annealing temperature is closely related to the damage recovery due to helium irradiation.     

Theoretical study on composition-dependent properties of ZnO·nAl2O3 spinels. Part II: Mechanical and thermophysical

Knowledge on the mechanical and thermophysical properties of ZnO·nAl₂O₃ is essential for practical applications. Based on the first-principles calculations and the bond valence method, the disordered spinel-type structure of ZnO·nAl₂O₃ (n = 1–4) was constructed to investigate the composition-dependent mechanical and thermophysical properties. The effects of cation substitution on the hardness, elastic modulus, thermal expansion, and thermal conductivity were revealed from the insights into the chemical bonds. At a higher n, the tetrahedral bond is stronger, manifested as its higher hardness and bulk modulus as well as smaller thermal expansion coefficient. Meanwhile, the octahedral bond is weaker, leading to the lower hardness and bulk modulus, along with the larger expansion coefficient. In consequence, the hardness and elastic moduli of ZnO·nAl₂O₃ are improved moderately while the expansion coefficient is decreased with the rise of n. Due to the different vibration characteristics of Zn^IV and Al^IV, the cation disorder in the 8a site provides the primary source of phonon scattering, resulting in the dramatic reduction of thermal conductivity as n increases. The understanding offers guidance on the application-oriented design of new oxide spinels.     

高阻相对La2／3Ca1／3MnO3低场磁电阻效应的影响

实验研究了La2／3Ca1/3MnO3系统晶界上掺杂(YSZ)对其输运性能和磁电阻效应(MR)的影响。样品是由溶胶．凝胶法制成的。通过对样品的电输运特性的测量表明,在掺杂量(x)低于2％时,掺杂引起电阻的增大并降低了金属．绝缘体转变温度;当掺杂量高于2％时电阻逐渐减小,且转变温度增加。而低场磁电阻效应随掺杂量增加,在x=1％时达到最大。     

Mn对Fe_3Al合金室温力学性能的影响

Ｍｎ对Ｆｅ_３Ａｌ合金室温力学性能的影响楼白杨，刘茂森，毛志远，涂江平，肖延龄，钟映宏（浙江大学）Ｆｅ３Ａｌ金属间化合物具有抗氧化耐腐蚀性良、比强度高和成本低等特点［１，２］，从而具有可观的工程应用前景。对这种材料目前国内研究的热点之一是改善其室温塑?..     

REACTIONS OF PYRITE IN CATALYTICAL OXIDATION ACID LEACHING SYSTEM

ＲＥＡＣＴＩＯＮＳＯＦＰＹＲＩＴＥＩＮＣＡＴＡＬＹＴＩＣＡＬＯＸＩＤＡＴＩＯＮＡＣＩＤＬＥＡＣＨＩＮＧＳＹＳＴＥＭ￥Ｘｉａ，Ｇｕａｎｇｘｉａｎｇ；Ｔｕ，Ｔａｏｚｈｉ；Ｙａｎｇ，Ｈａｎｌｉｎ；Ｓｈｉ，Ｗｅｉ（ＩｎｓｔｉｔｕｔｅｏｆＣｈｅｍｉｃａｌＭｅｔ...     

HIGH TEMPERATURE CORROSION OF PREOXIDIZED Ni-Al ALLOY IN CHLORINE

ＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＣＯＲＲＯＳＩＯＮＯＦＰＲＥＯＸＩＤＩＺＥＤＮｉ－ＡｌＡＬＬＯＹＩＮＣＨＬＯＲＩＮＥＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＣＯＲＲＯＳＩＯＮＯＦＰＲＥＯＸＩＤＩＺＥＤＮｉ－ＡｌＡＬＬＯＹＩＮＣＨＬＯＲＩＮＥ￥Ｔｕ，Ｊｉａｎｇｐｉ...     

机械CAD的Delphi实现技术

介绍用Delphi开发机械CAD的优势和常用技术，叙述网络化机械CAD系统的构成与实现技术，结合机械CAD的开发实例叙述其程序设计方法和技巧，并介绍相应的数据库技术。     

基于SPI双机通信的弧光保护系统

针对弧光保护系统的实际需要,设计了一种基于SPI的双机通信系统。简要阐述了该系统的设计思路,并给出了具体的实现方法。实验表明,采用该方法能够满足实际工程中的需求,对于其他SPI的应用也有很好的借鉴价值。