碳纳米管表面化学镀Ni的研究

通过对镀Ni前碳纳米管的氧化、敏化和活化处理,在碳纳米管表面增加活化点,成功地在碳纳米管表面镀上一层金属Ni,并用TEM对镀Ni前后的碳纳米管进行了表征.研究表明,用强酸对碳纳米管氧化处理后,可在碳纳米管表面产生大量官能团,改善表面性能,有利于对碳纳米管进行敏化和活化处理.尽可能多的活化点将有利于金属Ni在碳纳米管表面沉积,从而获得连续的金属Ni镀层,提高化学镀的质量.     

碳纳米管的化学镀银

碳纳米管因其优异的力学、物理性能，是一种理想的复合材料增强体。通过化学镀可在碳纳米管表面镀上一层连续的银镀层，以增强碳纳米管与金属基体的界面结合力．本文研究了在碳纳来管上化学沉积银的工艺及其影响因素．SEM、TEM观察表明：氧化、活化及镀是影响镀层质量的最重要因素．尽可能多的活化点以及尽可能慢的镀速将大大改善镀层质量。     

施镀时间和浓度对碳纳米管镀Ni层厚度的影响

为降低碳纳米管的表面活化能,改善碳纳米管与金属基体的相容性,采用化学镀的方法,在碳纳米管表面镀覆一层金属Ni.研究了施镀时间和镀液浓度对碳纳米管表面镀Ni层厚度的影响.结果表明:随着施镀时间延长,Ni沉积颗粒变大导致镀Ni层变厚;镀液浓度增加,碳纳米管表面沉积的Ni颗粒增多,镀Ni层逐渐致密.本实验工艺条件下,镀液浓度为0.08 mol/L,反应时间为30 min时,可以在碳纳米管表面镀覆一层界面结合良好且致密的Ni层,其厚度约为10nm.热处理能有效缓解镀Ni层应力,改善界面结合.     

施镀时间和浓度对碳纳米管镀Ni层厚度的影响

为降低碳纳米管的表面活化能, 改善碳纳米管与金属基体的相容性, 采用化学镀的方法, 在碳纳米管表面镀覆一层金属Ni。研究了施镀时间和镀液浓度对碳纳米管表面镀Ni层厚度的影响。结果表明: 随着施镀时间延长, Ni沉积颗粒变大导致镀Ni层变厚; 镀液浓度增加, 碳纳米管表面沉积的Ni颗粒增多, 镀Ni层逐渐致密。本实验工艺条件下, 镀液浓度为0.08 mol/L, 反应时间为30 min时, 可以在碳纳米管表面镀覆一层界面结合良好且致密的Ni层, 其厚度约为10 nm。热处理能有效缓解镀Ni层应力, 改善界面结合。     

碳纳米管表面修饰改性、机理研究现状及展望

碳纳米管具有优异的力学、物理性能,是理想的复合材料增强体.金属/碳纳米管复合材料已成为当今的研究热点.由于碳纳米管易团聚,与基体的相容性差,严重影响了基体和增强体之间的结合.为了增强其相容性,需对碳纳米管表面进行修饰.介绍了碳纳米管表面修饰的方法,综述了国内外的研究现状,展望了碳纳米管表面修饰的发展与应用前景.     

碳纤维表面的化学镀铜

制备碳纤维增强金属基复合材料时,在碳纤维表面可以用化学镀的方法镀复一层铜薄膜,以改善纤维与金属之间的润湿性,提高其界面结合强度,有效地传递应力.本文研究一种具有较高沉铜速度的碳纤维表面化学镀铜液.应用正交试验分析等方法研究影响沉铜速率的诸因素,提出采用的镀液成分范围.     

碳纳米管增强铝基复合材料界面控制研究进展

碳纳米管被认为是下一代最理想的铝基复合材料增强相,其与铝基体的界面结合情况是影响复合材料性能的重要因素之一。介绍了碳纳米管与铝基体界面反应条件以及界面反应产物对复合材料性能的影响,从碳纳米管表面金属包裹、碳纳米管表面化学键的修饰、制备工艺参数等方面综述了界面优化的方法,并讨论了界面优化对碳纳米管增强效率的影响。     

多壁碳纳米管表面的钴-铁化学镀(英文)

采用化学镀法在多壁碳纳米管表面沉积钴-铁涂层。主要研究了镀液中钴盐和铁盐的摩尔比、络合剂浓度和镀液温度对镀层的影响。在钴-铁的摩尔比为9∶1,络合剂浓度为0.32mol/L,镀液温度为60℃时,可得到的较为平整的镀层,且镀层中钴-铁摩尔之和达90%以上。其他条件下,则会在镀层中出现金属颗粒或钴-铁含量过少的情况。     

碳纳米管表面包覆研究进展

由于碳纳米管特殊的微观结构,使其具有优异的力学、电学和热学性能,是制备高性能CNTs/金属复合材料的理想增强体。然而,CNTs在金属基体中的分散性和润湿性问题严重阻碍了CNTs的应用,但CNTs作为增强体的潜力仍是巨大的。系统的阐述了CNTs表面包覆方法的分类和现状,主要有化学镀、复合电镀、化学气相沉积(CVD)和羰基热分解,并对各种方法利弊作了简要的分析。     

镀钴碳纳米管的制备及其电磁特性

在碳纳米管表面镀覆磁性金属粒子,可获得电磁性能优异的复合材料.对碳纳米管进行预处理,再用化学镀法在其表面包覆钴金属制备碳纳米管-维复合材料.用透射电子显微镜(TEM)、能谱仪、振动样品磁强计、矢量网络分析仪分析了复合材料的形貌、成分及电磁性能,并研究了化学镀工艺对镀层沉积速率的影响.结果表明:镀覆后碳管表面包覆了一层钴...     

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.