V2O5薄膜制备,结构及光学性质研究

Ｖ２Ｏ５薄膜是全固态电致变色器件扣锂离子储存层和很好个候选材料之一。本研究采用反应蒸发、优化实验条件,在加热基片上沉积了性能理想的Ｖ２Ｏ５薄膜,分别采用ＸＲＤ,ＡＥＳ,ＸＰＳ和紫外－近红外分光光度计研究了薄膜的晶态结构、组份、钒离子价态和光学等特生。研究结果表明,刚制备的薄为非晶结构,经过一定温度热处理后开始结晶,薄膜的组分为ＶＯ２．４６,含有少量的Ｖ＾＋４;吸收光谱存在两个不同的变化区域,高能区     

纳米V2O5新相的制备与表征研究

用水解法制备纳米Ｖ２Ｏ５经不同温度退火处理后，用ＸＲＤ、ＴＥＭ、ＤＴＡ、ＩＲ实验手段对纳米Ｖ２Ｏ５的显微结构进行表征，结果表明，在２９０℃退火温度以下，形成一种与正交Ｖ２Ｏ５正交相。该新相内含结构水，对Ｘ射线衍射有显著影响。晶体结构上与正交相相比，畸变严重，氧原子远离钒原子程度不等。新相颗粒为球状，平均粒径为６－８ｎｍ。     

GaN材料的GSMBE生长

在国内首次用ＮＨ３作氮源的ＧＳＭＢＥ方法在α－Ａｌ２Ｏ３衬底上生长出了ＧａＮ单昌外延膜。ＧａＮ生长速率可达０．５μｍ／ｈ。ＧａＮ外延膜的（０００２）双晶Ｘ射线衍射峰回摆曲线的半高宽最窄为８ａｒｃｍｉｎ。霍尔迁移率为５０ｃｍ＾２／Ｖ．ｓ。对质量好的ＧａＮ膜，室温阴性发光谱上只有一个强而锐的近岸边发光峰，谱峰位于３７２ｎｍ处，谱峰半高宽为１４ｎｍ（１２５ｍｅＶ）。     

ZrO2（Y2O3）纳米粉在超高压下快速烧结

研究了超高压（５ＧＰａ）、高温（１３５０℃）下烧结的ＺｒＯ２（Ｙ２Ｏ３）纳米材料的结构及相关系。结果表明：水解法制备的纳米（９ｎｍ）２．２Ｙ－ＺｒＯ２粉体经超高压烧结１０ｓ，致密度即达９９．５％以上，晶粒迅速长大达６０ｎｍ。在０￣９９ｓ范围内，随烧结时间延长，２．２Ｙ－ＴＺＰ的ｔ相增加，四方度（ｃ·ａ＾－１）减小，表明Ｙ２Ｏ３固溶进入ＺｒＯ２晶格内。     

V_2O_5熔体的微量氧化还原研究

将７００、８００、１１００℃三种温度下的Ｖ２Ｏ５熔体制得Ｖ２Ｏ５溶胶,在非晶玻璃基片上将Ｖ２Ｏ５溶胶制成Ｖ２Ｏ５凝胶薄膜试样．通过对Ｖ２Ｏ５凝胶薄膜试样的电阻随温度的变化测试和电子能谱（ＥＳＣＡ）和Ｘ射线衍射分析发现Ｖ２Ｏ５凝胶薄膜中有四价钒的存在,本文从Ｖ２Ｏ５熔体的微量氧化还原和晶体结构的角度分析讨论了微量氧化还原影响钒离子价态变化的机理．     

氮对纳米硅氮薄膜晶化的影响

在电容式耦合等离子体化学气相沉积系统中，用高氢稀释硅烷和氮气为反应气氛制备纳米硅氮（ｎｃ－ＳｉＮｘ２Ｈ）薄膜，结果表明，当Ｎ２／ＳｉＨ４气体流量比（Ｘｎ）从Ｉ增加为４时，薄膜的晶态率从５８％降至１４％，晶粒尺寸从１０ｎｍ降至５ｎｍ，Ｎ／Ｓｉ含量比从０．０３增至０．１２，当Ｘｎ≥５，则生成非晶硅氮（ａ－ＳｉｕＮｘ２Ｈ）薄膜，当Ｘｎ从１增加为１０时，薄膜暗电导率从１０＾－５（Ωｃｍ）＾－１降至１０＾－     

Sol—Gel法合成K（Ta,Nb）O3材料

以金属醇盐乙醇钾［Ｋ（ＯＣ２Ｈ５）］，乙醇铌［Ｎｂ（ＯＣ２Ｈ５）５］和乙醇钽［Ｔａ（ＯＣ２Ｈ５）５］为原料，用Ｓｏｌ－Ｇｅｌ法合成了Ｋ（Ｔａ，Ｎｂ）Ｏ３超细粉末和薄膜，研究了工艺参数如前驱体溶液浓度、热处理温度等因素对材料结构及物性的影响。粉料的粒径为２０￣４０ｎｍ，所需合成温度约为７００℃，比通过传统的固相反应制备同种材料的合成温度低近１００℃；以ＳｒＴｉＯ３（１００）单晶作基片，采用匀胶法获得     

PREPARATlON AND OPTICAL PROPERTIES OF a-AXIS ORIENTED β-BaB_2O_4 SURFACE CRYSTALLIZED GLASS

采用传统熔融方法制备了透明ＢａＯ－Ｂ２Ｏ３玻璃。经受控热处理后，由ＸＲＤ谱发现存在ａ轴取向ＢＢＯ结构的微晶薄膜层。由Ｓｃｈｅｒｒｅｒ公式计算得出晶粒尺寸约２０ｎｍ。在１．０６４μｍＱ开关Ｎｄ：ＹＡＧ强激光作用下，观察到了倍频效应的产生（ＳＨＧ）。     

高氢稀释硅烷加乙烯法制备纳米硅碳薄膜

在等离子体化学气相沉积系统（ＰＥＣＶＤ）中，使用高氢稀释硅烷（ＳｉＨ４）加乙烯（Ｃ２Ｈ４）为反应气氛制备了纳米硅碳（ｎｃ－ＳｉＣｘ＾２Ｈ）薄膜，随着（Ｃ２Ｈ４＋ＳｉＨ４）／Ｈ２（Ｘｇ）从５％时，由于Ｈ蚀刻效应的减弱，薄膜的晶态率从４８％下降到８％，平均晶粒尺寸在３．５－１０ｎｍ。当Ｘｇ≥６％时，生成薄膜为非晶硅碳（ａ－ＳｉＣｘ＾２Ｈ）薄膜。ｎｃ－ＳｉＣｘ＾２Ｈ薄膜的电学性质具有与薄膜的晶态率紧密相     

纳米V2O5的晶体缺陷与导电性能研究

用溶胶－凝胶法制备纳米Ｖ２Ｏ５粉体，利用ＩＲ、ＥＳＲ结构分析手段研究晶体缺陷，并用阻抗谱研究它的导电性能。阻抗谱表明，在较低退上得到的纳米Ｖ２Ｏ５粉体（平均粒径为５．０ｎｍ）表现出超常的导电性能，其电导率高于其它样品二个数量级。ＩＲ、ＥＳＲ分析指出，该样品中Ｖ２Ｏ５结构发生严重畸变，引起氧空位浓度增加，并认为是导致良好导电性能之主要原因。     

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.     

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.……     

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.     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

The Influence of Nitrogen and Boron Implant into Silicon Substrate on the Phase and Internal Stress of c-BN Films

Cubic boron nitride(c-BN) film was deposited on a Si (100) substrate by the RF-magnetron sputtering.The mainly problems for fabrication of c-BN films are the low purity and high intrinsic compressive stress. In order to solve the two problems, the c-BN film with the buffer interlayer was deposited on the substrate which had been implanted with nitrogen and/or boron ions. The results show: the implantation of nitrogen ions can obviously increase c-BN content and reduce the internal stress slightly; while the implantation of boron shows no obvious improvement to the content of c-BN, which can reduce the internal stress in the film obviously. In addition, it is suggested that the implantation of nitrogen and boron shows the best result, which not only can increase the content of c-BN, but also reduce the internal stress in the c-BN film obviously.