沉积激光能量对CuAlO2薄膜光学性质的影响

采用脉冲激光沉积法制备了CuAlO2薄膜.在沉积激光能量100～180mJ范围内原位沉积的薄膜并在N2气氛下900℃异位退火1h处理后,所有薄膜均为高度c轴取向的单相CuAlO2薄膜,晶粒尺寸～49nm.随着沉积激光能量的增大,薄膜厚度增加,表面颗粒尺寸明显增大,在可见光区的平均透射率下降.室温光致发光谱发现,CuAlO2薄膜在350nm附近有一个自由激子复合发光峰,说明在CuAlO2宽带隙半导体中存在直接带间跃迁,这对于该材料在光电子领域如发光二极管的应用具有重要意义.     

络合溶胶-凝胶法制备CuAlO2微晶及其光学性能研究

以柠檬酸为络合剂,采用络合溶胶-凝胶法合成CuAlO2微晶.通过TG-DTA、XRD、TEM等手段对凝胶的热分解机制、CuAlO2微晶的形成过程、微晶的物相结构、微观形貌、粒度大小等进行了研究.结果表明:以硝酸铜、异丙醇铝和乙二醇为反应原料,加入柠檬酸作为络合剂,可以与金属离子形成络合物,从而降低了合成CuAlO2微晶的温度,在1050℃煅烧即可得到颗粒细小、组分均匀、铜铁矿型CuAlO2微晶,晶体粒径为150nm左右.利用紫外-可见光谱分析,CuAlO2微晶的光学带隙约为3.75～4.05eV.     

Co掺杂CuAlO2粉体磁性的讨论

利用固态反应法合成了纯相的CuAlO2和过渡金属元素Co掺杂的CuAlO2样品。通过X射线衍射仪分析可知:未掺杂样品和1%(摩尔分数)Co掺杂的样品都是单相,其中没有CuO等杂相存在,而掺杂浓度分别为5%、10%和20%的样品中都出现了CuAlO2以外的杂相,这表明Co在CuAlO2粉体样品中的杂质固溶度一般低于5%。综合物性测试系统测得的与磁性有关数据表明:未掺杂及Co掺杂(1%)的纯相CuAlO2样品只具有顺磁性,而多相的Co掺杂样品从5～300K都没有表现出如第一性原理理论所预言的铁磁性,这说明样品中所掺入的Co离子只是具有局域磁矩的顺磁杂质中心,并不能形成长程的铁磁序,进一步表明基于第一性原理的理论计算可能高估了过渡金属磁性杂质在氧化物半导体这种关联体系中的铁磁耦合作用。     

p型透明导电CuAlO_2薄膜的透光性能研究

CuAlO2(CAO)透明薄膜是一种铜铁矿结构p型直接带隙透明氧化物薄膜,该型薄膜样品的可见光透射率高达80%。随着基片温度的升高,薄膜的透射率减小;随着工作压强和靶基距的增大,薄膜的透射率增大;随着退火温度的升高,薄膜的透射率增大,有"蓝移"现象;随着溅射时间的延长,薄膜的透射率减小,也有"蓝移"现象。目前,利用该薄膜已成功制得了透明的臭氧传感器和透明光电板等器件,显示了CAO的应用前景。     

p型透明导电氧化物CuAlO2薄膜的研究进展

透明导电氧化物(TCO)的出现开拓了光电子器件研究的新领域.但p型TCO的相对匮乏严重制约了透明氧化物半导体(TOS)相关器件的开发与应用.CuAlO2作为一种天然的p型TCO成为近年来p型TCO的研究热点.介绍了p型TCO的研究现状,综述了不同制备方法制备p型CuAlO2薄膜的研究进展,以及在器件方面的应用,并对其前景进行了展望.     

CuAlO2纳米晶的水热-分解制备及表征

采用新制备的Cu2O和Al(OH)3为反应原料,利用水热-分解法制备了p型半导体CuAlO2纳米晶.采用X射线衍射(XRD)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)和紫外-可见(UV-Vis)吸收光谱对其结构、形貌、表面组分和性能进行了表征分析,对反应机理进行了讨论.结果表明在水热条件下首先是Al(OH)3转化为γ-AlOOH,然后γ-AlOOH分解并与Cu2O反应生成CuAlO2纳米晶.确定了以Cu2O和Al(OH)3溶胶为反应原料,采用水热-分解法制备CuAlO2纳米晶的最佳反应条件.     

等离子体辅助铝诱导纳米硅制备多晶硅的研究

以超白玻璃为衬底,利用热丝化学气相沉积和磁控溅射法制备了Glass/nc-Si/Al叠层结构,置入管式退火炉中进行等离子体辅助退火.样品在氢等离子体氛围下进行了400,425和450℃不同温度,5h的诱导退火,用光学显微镜和拉曼光谱对样品进行了性能表征.结果表明随着诱导温度升高,样品的Si(111)择优取向越来越显著;晶粒尺寸不断增大,在450℃诱导温度下获得了最大晶粒尺寸约500μm的连续性多晶硅薄膜,且该温度下薄膜晶化率达97％;薄膜的结晶质量也随着温度的升高而不断提高.样品经450℃诱导后的载流子浓度p为5.8× 1017 cm-3,薄膜霍尔迁移率μH为74 cm2/Vs.还从氢等离子体钝化的角度分析了等离子体环境下铝诱导纳米硅的机理.     

柱状晶形貌TiO2膜厚对FTO/TiO2镀膜玻璃光催化活性影响

采用溶胶凝胶法,在FTO(SnO2:F)低辐射镀膜玻璃衬底上制备了柱状晶体结构的TiO2薄膜,获得双层结构FTO/TiO2镀膜玻璃样品.研究了TiO2薄膜厚度对FTO/TiO2镀膜玻璃样品的光催化活性、低辐射性能以及透光性能的影响.结果表明,FTO/TiO2镀膜玻璃样品光催化活性随着TiO2薄膜厚度的增加先升高后下降,在TiO2薄膜厚度为300 nm时光催化活性最佳;低辐射性能随着TiO2薄膜厚度的增加而下降,但TiO2薄膜厚度为300 nm时仍然具备一定的低辐射性能;透光性能与TiO2薄膜膜厚的关系不大,可见光透射比保持在72%左右;表面平均粗糙度约为1 nm,表面光滑,不易沾染油污灰尘.该镀膜玻璃在保证低辐射建筑节能和透光的前提下,兼具光催化自清洁功能,具有很好的应用前景.     

石英衬底上柱状多晶硅薄膜的制备

利用射频等离子体增强化学气相沉积法(RF-PECVD)在已经预沉积有非晶硅薄膜的石英衬底上低温沉积了N/I非晶硅薄膜, 对样品进行了两步快速光热(RTP)退火. 采用 Raman、X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等测试仪器对样品退火前后的结晶状况和微观形貌进行了分析. 结果表明, 该N/I非晶硅薄膜退火后的晶化率达到了94%左右, 断面形貌为柱状结构, 样品中的平均晶粒尺寸约30nm, 晶粒团簇的尺寸最大约1.5μm.     

Eu、Nd、Y稀土掺杂CuAlO_2纳米粉末制备及相组织研究

采用柠檬酸络合的无机盐溶胶-凝胶法制备稀土掺杂铜铁矿结构的CuAlO2粉末,掺杂元素M为稀土Eu、Nd、Y。用DSC-TGA、X射线衍射仪、紫外-可见光分光光度计等测试方法分别对掺杂CuAl1-x MxO2粉末的形成过程、物相结构、光学性能等进行研究。结果表明,稀土掺杂前驱体粉末经950℃煅烧后形成CuAlO2相;经1 100℃保温4h的煅烧后,粉末相组成取决于稀土掺杂量,当稀土元素M(Eu、Nd和Y)的掺杂量为0.5%时,试样由CuAlO2主相和少量CuO杂相组成,当掺杂量≥1%时,由CuAlO2主相、少量CuO和MAlO3杂相组成,YAlO3杂相峰强度较低。提高煅烧温度有利于掺杂元素的溶入,生成CuAl1-xMxO2纯相,但提高到1 150℃时CuAlO2分解;Eu掺杂量1%时,掺杂样品光学带隙增大,电阻率减小,光电性能得到改善。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.