不同厚度四面体非晶碳薄膜的拉曼表征和内应力

为了探讨膜厚对四面体非晶碳薄膜拉曼结构表征和内应力的影响规律，进而确定应力与拉曼光谱之间的关系，采用过滤阴极真空电弧技术以相同的工艺条件在P（100）单晶抛光硅衬底上制备了从3nm～350nm不同厚度的四面体非晶碳薄膜。利用表面轮廓仪和原子力显微镜测试膜厚，表面轮廓仪确定曲率半径并计算薄膜应力，共聚焦拉曼光谱表征薄膜的结构细节。实验发现，随着膜厚的增加，四面体非晶碳薄膜的应力持续下降，当膜厚超过30nlll时，应力的下降趋势变得平缓，并保持在小于5GPa的较低水平。随着膜厚的增加，可见光拉曼光谱中衬底硅的一阶和二阶谱峰强度逐渐降低，在50nm～80nm膜厚范围，半高宽最窄，峰强最高，能够最有效地获得拉曼结构信息。随着膜厚的增加和应力的下降，非晶碳一阶谱峰的峰位表现为逐渐向低频偏移。     

TiN/Si3N4纳米多层膜的生长结构与超硬效应

采用磁控溅射方法制备了一系列不同Si3N4和TiN层厚的TiN/Si3N4纳米多层膜,采用X射线衍射、高分辨电子显微分析和微力学探针表征了薄膜的微结构和力学性能,研究了Si3N4和TiN层厚对多层膜生长结构和力学性能的影响.结果表明:当Si3N4层厚小于0.7 nm时,原为非晶的Si3N4在TiN的模板作用下晶化并与之形成共格外延生长的柱状晶,使TiN/Si3N4多层膜产生硬度和弹性模量异常升高的超硬效应.最高硬度和弹性模量分别为34.0 GPa和353.5 GPa.当其厚度大于1.3 nm时,Si3N4呈现非晶态,阻断了TiN的外延生长,多层膜的力学性能明显降低.此外,TiN层厚的增加也会对TiN/Si3N4多层膜的生长结构和力学性能造成影响,随着TiN层厚的增加,多层膜的硬度和弹性模量缓慢下降.     

超薄Au膜的微结构及电学特性

用直流磁控溅射在室温Si基片和载玻片上制备了厚度为7.6～81.3nm超薄Au膜,用X射线衍射及数字电桥对薄膜的微结构和电学性质进行了测试分析.微结构分析表明:制备的超薄Au膜仍为面心立方多晶结构;在膜厚d＜46.3nm时,(111)晶粒平均晶粒尺寸随膜厚增加逐渐增大,当d＞46.3nm后,晶粒尺寸几乎保持不变,甚至有所减小;(220)晶粒的平均晶粒尺寸则总是随膜厚的增加而增大.薄膜晶格常数均比PDF标准值(0.4078nm)稍小,随膜厚增加,薄膜晶格常数由0.4045nm增大到0.4077nm.电阻率分析结果表明,随着膜厚的增加,薄膜的电阻率经历了岛状膜的极大-网状膜的急剧减小-连续膜的缓慢减小.膜厚d＞46.3nm后,由于薄膜中长出新的(111)小晶粒,电阻率略有增加.     

Cu/Zr纳米多层膜微结构与力学性能

本文利用直流磁控溅射方法在石英玻璃基片上制备一系列自支撑Cu/Zr纳米多层膜,使用箱式电炉对多层膜进行退火处理,利用显微硬度计,X射线衍射仪、扫描探针显微镜表征了多层膜的力学性能与微观结构,研究了不同工艺参数对纳米多层膜性能的影响.研究结果表明:当Cu调制层厚从42 nm增加至140nm时,多层膜显微硬度从4.9 GPa逐渐降低至4.0 GPa;当Zr调制层厚从3.2 nm增加至4.8 nm时,显微硬度值从6.51 GPa降低至5.64 GPa,硬度值降低13.4%,而从4.8 nm增至8 nm时,显微硬度值变化不大(约5.7 GPa);合适的温度退火时,多层膜微观缺陷消失,表面形貌更均匀,显微硬度增加.利用Chu和Barnett提出的硬度增强理论模型对Cu/Zr纳米多层膜表现出的超硬现象进行了理论分析和解释.     

离子束流和基底温度对ZrN/TiAlN纳米多层膜性能的影响

本文利用高真空离子束辅助沉积系统(IBAD),在室温下制备了ZrN、TiAlN和一系列ZxN/TiAlN纳米多层膜,利用XRD、纳米力学测试系统和多功能材料表面性能实验仪,分析了束流和基底温度对薄膜的微结构和机械性能的影响.结果表明大部分多层膜的纳米硬度与弹性模量值都高于两种个体材料硬度的平均值,当辅助束流为5 mA时,多层膜硬度达到30.6 GPa.基底温度的升高,会显著降低薄膜的残余应力,但对薄膜的硬度,摩擦系数没有明显影响.     

离子束溅射沉积Co纳米薄膜表面特征AFM、XPS分析

采用离子束溅射沉积法，在单晶Si基片上制备了不同厚度（1nm-100nm）的Co纳米薄膜。利用原子力显微镜和X射线光电子能谱仪对不同厚度的Co纳米薄膜的表面进行了分析和研究。结果表明：当薄膜厚度为1nm～10nm时，沉积颗粒形态随着薄膜厚度的增加将由二维生长的细长胞状过渡到多个颗粒聚集成的球状；当膜厚继续增加，小颗粒球消失，集结成大颗粒球，颗粒球呈现三维生长状态；表面粗糙度随着膜厚（膜厚为1nm～10nm）的增大，呈现先增加后减小的趋势，在膜厚为3nm时出现极值。通过XPS全程宽扫描和窄扫描，薄膜表面的元素成分为Co：主要以金属Co和Co氧化物的形式存在。     

ZrN/TiAlN纳米多层膜的制备及其结构与性能的研究

利用高真空离子束辅助沉积系统在室温下制备了ZrN,TiAlN和一系列ZrN/TiAlN纳米多层膜,利用X射线衍射仪、纳米力学测试系统和多功能材料表面性能实验仪表征了薄膜的微结构和机械性能,分析了调制周期对薄膜结构与机械性能的影响.结果表明大部分多层膜的纳米硬度与弹性模量值都高于两种个体材料硬度的平均值,当调制周期为6.5 nm时,多层膜硬度达到最高(30.1 GPa),弹性模量、粗糙度、摩擦以及划痕测试均达到最佳效果.     

FCVA法制备的超薄类金刚石薄膜的结构分析

用真空阴极过滤电弧(Filtered Cathode Vacuum Arc,FCVA)法制备厚度分别为50 nm,30 nm,10 nm,5 nm,2 nm的类金刚石(DLC)薄膜,利用拉曼光谱和电子能量损失谱研究了薄膜的结构,分析了硬度和内应力的变化趋势。结果表明,随着薄膜厚度的减小,可见光拉曼光谱高斯分解的G峰位置向低波数方向移动,D峰和G峰强度之比Id/Ig不断增大,G峰面积与D峰面积之比Ag/Ad减小;说明随着薄膜厚度的减小,DLC薄膜中的sp3键含量减少,有序化的sp2团簇增加。电子能量损失谱的结果也表明薄膜厚度的减小会引起薄膜中sp3键含量的减少。当薄膜的厚度由50 nm变为30 nm时,薄膜硬度由53.85 GPa减小为39.64 GPa,内应力由4.63 GPa降低为3.47 GPa,随着厚度降低,薄膜的硬度和内应力呈下降趋势。     

膜厚对SnO2∶Sb薄膜红外光学性能的影响

采用溶胶-凝胶法在玻璃基底上制备了Sb掺杂SnO_2(SnO_2∶Sb)薄膜。研究了膜厚对SnO_2∶Sb薄膜红外光学性能的影响,利用X射线衍射仪、分光光度计、霍尔效应测试系统对薄膜样品进行表征和测试。结果表明:SnO_2∶Sb薄膜为四方金红石型结构;当膜厚为1220nm时,薄层电阻最小,为157Ω/□;在红外波段,透射率随膜厚的增加显著下降,当膜厚为890nm时,在波长2000nm处,透射率接近于0,膜厚为1220nm时,在波长1750nm处,透射率为0。     

Ag反射膜厚度对PbTe热电薄膜性能的影响

采用真空蒸发法制备相同厚度的PbTe薄膜,再利用RF磁控溅射法在上面制备不同厚度的Ag反射膜,采用XRD、SEM、FTIR和四探针法分别对制备样品的物相组成、表面形貌、透射率和电阻率进行测试,结果显示,所制备的薄膜具有明显的〈100〉方向择优取向,呈多晶结构,随着反射膜厚度的增加,薄膜结晶性能先降低后增加;晶粒尺寸增加,表面粗糙程度先降低后增加;薄膜光学性能在一定膜厚范围内,随着反射膜厚度的增加透射率降低,超过一定膜厚时,透射率降为零;随着反射膜厚度的增加,电阻率呈先急剧降低后缓慢降低的趋势。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。