溶胶—凝胶法制备掺氟二氧化硅低介电常数薄膜

采用溶胶－凝胶法制备了低介电常数SiO2薄膜和SiOF薄膜，F的掺入明显地降低了SiO2薄膜的介电常数。研究了F的掺杂量对薄膜介电常数的影响，测定了10－300kHz范围内电容随频率变化的曲线，并计算了相应介电常数。二次离子质谱对薄膜深度分析的结果表明，F在薄膜中的分布是不均匀的。讨论了溶胶－凝胶法制备掺F的SiO2薄膜过程中各种因素对介电常数的影响，并用原子力显微镜观察了薄膜的表面形貌。     

溶胶-凝胶SiO2在变色薄膜中的应用

变色薄膜是一种非常有用的光学产品。用溶胶－凝胶SiO2作为变色薄膜中的介质层（Cr/SiO2/Al）能明显提高产品的质量和生产效率。本文介绍了溶胶－凝胶SiO2薄膜的制作方法，提出了用酸性催化控制SiO2溶胶过程；用网线辊涂布的方法形成薄膜，连同烘烧后处理完成SiO2凝胶过程。文章还对SiO2薄膜的光学特性和在制备变色薄膜中相关条件对整个薄膜性能的影响进行了分析。     

采用Sol-gel法制备梯度复合热释电薄膜

以TaCl5和NbCl5为原料制备了乙醇钽和乙醇铌,对溶胶-凝胶法制备KTa1-xNbxO3薄膜的工艺过程、影响因素进行了研究,提出了优化的制备工艺,采用溶胶-凝胶法在Pt/Ti/SiO2/Si衬底上制备了组分梯度复合KTa1-xNbxO3热释电薄膜.     

由多聚硅氧烷制备二氧化硅气凝胶

SiO2 气凝胶是一种新型轻质纳米多孔材料。本工作以多聚硅氧烷 (E -4 0 )为硅源 ,用溶胶 -凝胶法制备出了SiO2气凝胶。研究了催化剂、温度、水等因素对其溶胶 -凝胶过程的影响 ;讨论了F离子以及水对E -4 0水解 -缩聚反应的作用机理 ;并用孔径分布测定仪、TEM等方法对其微结构进行了研究。结果表明 :由E -4 0为硅源制备的SiO2 气凝胶骨架颗粒为十几nm ;孔径分布较广 ,其峰值在 3 0nm附近 ,此外 ,还存在几nm的微孔。     

实验条件对SiO2-MTES-CTAB纳米疏水薄膜的影响

以正硅酸乙酯(TEOS)为硅源,采用溶胶-凝胶技术,通过两步酸法控制实验条件引入有机硅烷甲基三乙氧基硅烷(MTES)和表面活性剂十六烷基三甲基溴化氨(CTAB),制备了疏水型SiO2前驱体溶胶.以旋涂法成膜出SiO2-MTES-CTAB纳米疏水薄膜,研究了正硅酸乙酯与甲基三乙氧基硅烷不同的混合比以及不同的热处理温度等对纳米疏水薄膜的影响,并且分析了纳米疏水薄膜的表面形态.研究表明,利用有机基团甲基三乙氧基硅烷改性SiO2溶胶和薄膜的热处理温度对制备的SiO2基纳米疏水薄膜的性能以及表面形态都具有非常重要的影响.     

折射率可调SiO_2薄膜及耐环境性宽频增透膜的制备

通过溶胶-凝胶法制备了折射率连续可调的SiO2薄膜,并将其应用于制备双层宽频增透膜。以正硅酸乙酯为前驱体,分别以盐酸和氨水为催化剂制备酸催化SiO2溶胶和碱催化SiO2溶胶;将酸催化和碱催化的SiO2溶胶按不同比例进行混合制得酸碱混合SiO2溶胶,最后通过浸渍-提拉法在K9玻璃上制备SiO2薄膜。椭偏仪测试结果表明SiO2薄膜的折射率在1.18~1.44之间连续可调,折射率随着酸催化SiO2溶胶比例的增加而增加。分别以折射率为1.41和1.18的SiO2薄膜为底层和上层,成功制备出在527和1053nm处同时高增透的双层宽频增透膜。最后,以六甲基二硅氮烷为修饰剂,通过增透膜表面的有机修饰,提高了宽频增透膜的疏水性和耐环境性。     

SiO2-TiO2光催化薄膜的制备及其晶化过程的研究

利用溶胶-凝胶法在石英玻璃表面制备出一层折射率可调的SiO2-TiO2光催化薄膜.采用X射线衍射分析、扫描电镜及氮气吸附实验等测试手段,研究了利用溶胶-凝胶法制备SiO2掺杂的TiO2薄膜的相变行为.提出了通过加入SiO2的比例超过10%时,在TiO2内部形成高度分散的SiO2网络,抑制TiO2晶粒的生长以及晶型转变,增加薄膜材料的热稳定性的方法.通过甲基橙水溶液的光催化降解实验表明:当SiO2的掺杂比例为10%,经过500℃以上的热处理后,所获得的SiO2-TiO2复合薄膜具有最大的光催化活性.     

SiO_2-ZrO_2复合膜的制备及其工艺参数的研究

采用溶胶-凝胶法制备SiO2-ZrO2复合薄膜,研究溶胶成分和烧结工艺对薄膜开裂及其性能的影响.采用乌氏黏度计、热重分析仪(TG-DTG)、X射线衍射分析仪(XRD)和原子力显微镜(AFM)对薄膜进行表征.结果显示,溶胶的组成、特定温度的升温速率对薄膜的开裂起决定性作用;当摩尔比为n(SiO2)∶n(ZrO2)=2.0∶0.5时,制得溶胶黏度适中、透明稳定,干燥的凝胶在0.5℃/min的升温速率下升至600℃焙烧2h,并在75、190和230℃附近缓慢升温且适当保温后,可得无裂缝且均匀、透明的SiO2-ZrO2复合薄膜,所制备的薄膜具有较大的比表面积和较窄的孔径分布.     

溶胶-凝胶法制备低折射率SiO2薄膜的过程控制研究

纳米多孔二氧化硅薄膜具有优良的物理化学特性和广阔的应用前景.以溶胶-凝胶法制备低折射率SiO2薄膜为例,对化学法镀膜中的溶胶制备、溶胶保存、薄膜制备等3个阶段进行了研究,利用透射电镜、红外光谱仪、原子力显微镜、椭偏仪等对溶胶和薄膜的特性进行了检测,并对其制备过程进行了控制,这对制备性能良好的薄膜材料及其产业化应用具有一定的指导意义.     

离子束增强沉积制备钽酸锂薄膜电性能分析

为提升钽酸锂薄膜的性能,提出一种离子束增强沉积法制备钽酸锂薄膜的新工艺。分别采用这种新工艺和溶胶-凝胶法制备了钽酸锂薄膜,并利用阻抗分析仪和铁电材料分析仪对制备样品进行了介电性能、铁电特性、漏电电流和热释电特性分析。实验结果表明,采用离子束增强沉积制备的钽酸锂样品经550℃退火后,介电常数为39.44,介电损耗为0.045;测试电场强度为400kV/cm时,漏电流为4.76×10-8 A/cm2,击穿场强为680kV/cm,热释电系数达到1.82×10-4 C/m2 K。相比之下,采用溶胶-凝胶方法制备的钽酸锂薄膜样品,其介电常数、介电损耗、漏电流都更大,击穿场强和热释电系数更低。从电性能参数比较可以看出,离子束增强沉积法比溶胶-凝胶法更适合用于制备钽酸锂薄膜。     

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.     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from