稀土La掺杂对Ru-La-Ti涂层阳极电催化性能的影响

利用热分解方法在不同温度下制备了不同摩尔分数La的三元涂层Ru0.3Ti(0.7～x)LaxO2,通过极化曲线测试和交流阻抗谱测试研究了所制备涂层的电催化活性,并用扫描电镜对涂层表面形貌进行了观察.测试结果表明,在涂层中引入La可以提高涂层阳极的电催化活性.La的掺杂量有一个最佳比,摩尔分数为0.5时电催化性最好;适当的热分解温度有利于La涂层阳极性能的提高,最佳温度为450℃.     

钛基Ru-La-Ti涂层阳极的电催化性能

利用热分解法制备了不同La含量的钛基Ru-La-Ti涂层阳极，并研究了所制备涂层的电催化性能。结果表明，在Ru-Ti涂层阳极中掺杂稀土元素La可以提高涂层阳极的电催化活性，且La的掺杂量存在一个最佳范围(La的摩尔分数O．2)。涂层阳极电催化活性提高的原因在于La的引入可以提高涂层的有效活性表面积。     

含硅钛阳极的制备及其电催化性能研究

为了研究硅组元对RuO2/Ti阳极电催化活性的影响,采用溶胶-凝胶法(Sol-Gel)制备了不同成分配比的RuO2-SiO2/Ti阳极,通过电极的析氯电位、析氧电位测试以及循环伏安性能测试,研究了所制备涂层的电催化活性.测试结果表明,在涂层阳极中引入Si可以提高涂层阳极的电催化性能,且Si引入的最佳值为0.1,0.3(摩尔分数).Ru-Si涂层阳极电催化性能提高的原因在于Si的引入可以增加涂层的活性表面积.     

Ir、Sn对钴系尖晶石结构涂层阳极的影响

利用热分解方法在钛基体上制备了不同组成的Ti/RuTiCoOx尖晶石结构涂层阳极,通过掺杂第四组元Ir或Sn以提高其各项性能.通过极化曲线、循环伏安曲线测试研究了添加Ir或Sn的尖晶石结构涂层的电催化活性,采用X射线衍射和扫描电子显微镜(SEM)对其表面结构和形貌进行了分析比较.结果表明,在三元涂层中引入Ir、Sn元素可以提高涂层阳极的电催化活性,加入Ir元素后,阳极涂层具有较低的析氯电位,阳极使用寿命较长.     

钛基钛锡钌锰纳米涂层的制备

采用热分解法制备了不同温度和元素含量配比的电解二氧化锰Ti/TiSnRuMn阳极纳米涂层.用XRD和SEM分析涂层的成分、结构和形貌,用循环伏安曲线和电位曲线评价涂层的电催化性能和使用寿命.结果表明,制备的涂层为均匀、单一的金红石固熔体结构.温度为500℃时,涂层表面裂纹最多,电催化性能最好;提高Ru与Ti以及Sn与Mn的含量比,涂层的表面裂纹逐渐减少.添加Mn能提高涂层的电催化性能,但改变Sn与Mn的含量比,涂层电催化性能变化不明显;而当Ti∶Ru＝2∶3时,涂层电催化性能最好,涂层的加速电解时间为870min.     

混合氧化物涂层钛基阳极的性能及其电子防腐蚀

辅助阳极是电子防腐蚀系统的关键部件之一,为提高其性能及寿命,利用热分解法制备了Ru-Ir-Sn-Ti混合氧化物涂层钛基阳极,用SEM,XRD,动电位极化曲线、强化电解寿命试验和热水器内胆电子防腐蚀试验考察了不同Sn含量的混合氧化物涂层钛电极的性能。结果表明:Ru-Ir-Sn-Ti混合氧化物涂层覆盖良好,呈均匀龟裂状;添加适量的Sn能提高涂层的电化学活性,含10%(摩尔分数)Sn涂层的电化学性能最优;含30%(摩尔分数)Sn涂层的强化电解寿命达58 h;混合氧化物涂层钛阳极在输入很小的电压时,能有效防止水下搪瓷碳钢在高硬度热水中的腐蚀,且能使阴极材料表面沉淀一层钙质层,增强了保护效果。     

含Pd-PdO纳米涂层钛阳极的电催化活性研究

从提高钛阳极在析氯环境的电催化活性出发,用溶胶-凝胶法制备了纳米级Pd-PdO/Ti涂层钛阳极。采用XRD分析了涂层的成分及相结构,测试不同烧结温度获得的阳极的电极电位和循环伏安曲线。研究结果表明,Pd-PdO/Ti涂层钛阳极具有极高的析氯电催化活性。     

PbO2-TiO2镀液中掺杂Ce对制备钛基锌电积阳极材料性能的影响

为了寻找出性能更佳的电积锌用钛基二氧化铅阳极,将CeO2,Ce(NO3)2分别掺杂在电镀液中制备了Ti/PbO2-TiO2阳极.以SEM,XRD分析方法对其形貌、组成元素进行了表征,应用加速电解寿命测试和电化学试验进行了性能测试,分别考察了掺杂CeO2和Ce(NO3)2对PbO2-TiO2阳极稳定性及电催化活性的影响.结果表明:Ti/PbO2-TiO2+CeO2阳极的电催化活性较好,且掺杂CeO2能改善Ti/PbO2-TiO2的导电性,提高了阳极的稳定性,使其电解寿命增长;Ti/PbO2-TiO2+Ce(NO3)2阳极的电催化活性也较好,但并不能增加阳极寿命.     

钛基IrO2-Ta2 O5氧化物阳极失效过程监测及失效机制探讨

为探讨氧化物阳极的失效机制,采用热分解法制备了钛基IrO2-Ta2O5氧化物阳极,利用扫描电镜(SEM)、循环伏安测试(CV)、电化学阻抗(EIS)监测了阳极在硫酸溶液的强化电解过程中表面形貌和电化学性能的变化.结果表明,氧化物阳极的失效并非由氧化物涂层本身失去电催化活性所致,而是由于工作过程中基体金属腐蚀钝化、失去导电载体作用而使涂层大面积剥离所致.     

溶胶-凝胶法制备的Ti/IrO2+Ta2O5阳极涂层性能

热分解法制备的涂层性能不够理想,现更多采用溶胶-凝胶法,但传统溶胶-凝胶法制备阳极仍存在工艺复杂、可操作性差的缺点.从电极的前驱体入手,将贵金属的无机盐制备成有机盐,采用溶胶-凝胶法制备了Ti/IrO2+Ta2O5阳极涂层,并与热分解法制备的涂层进行了对比研究.经SEM,EDX,循环伏安,电化学阻抗谱及强化电解寿命试验表明,与热分解法相比,由溶胶-凝胶法制备的氧化物阳极涂层表面呈现较多的龟裂纹,且有少量氧化铱晶簇析出,其电化学活性表面积增大,提高了电极的电催化活性,但稳定性降低.     

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.     

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.     

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.     

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)。