石墨烯基复合吸波材料的研究进展

石墨烯由于其独特的物理和化学性能,在吸波领域备受瞩目,成为吸波材料研究的一大热点。综述了石墨烯／磁性纳米颗粒复合吸波材料、石墨烯／导电聚合物复合吸波材料及石墨烯／纳米金属或金属氧（硫）化物复合吸波材料在吸波领域的应用研究现状,并展望了石墨烯基复合吸波材料未来的发展方向。     

碳纳米管吸波材料的研究现状与展望

碳纳米管因其独特的物理和化学性能10多年来一直备受关注,已有研究将其运用于军事科技领域,如吸波材料,但目前国内关于此类研究的报道还不多.较为全面地总结了近年来国内外对碳纳米管作为吸波材料的研究成果及其目前的研究现状,即简述碳纳米管的吸波机理;详细介绍碳纳米管薄膜、活性碳纳米管、磁性金属(合金)/碳纳米管、碳纳米管/聚合物基复合吸波材料的研究现状;展望未来吸波材料的发展方向.     

纳米磁性金属电磁波吸收剂的研究进展及展望

分析了纳米磁性金属系材料的电磁波吸收机理,总结了近年来国内外对包括单元磁性金属粉、多元磁性合金粉、陶瓷基核/壳结构纳米磁性金属颗粒膜、磁性金属薄膜及纤维等磁性金属电磁波吸收剂的研究现状,指出纳米磁性金属材料有望满足新型吸波材料"薄、轻、宽、强"的要求,并提出了今后纳米磁性金属吸收剂的研究方向.     

雷达用隐身吸波材料研究进展

本文综述了近年来国内外雷达波吸收材料的研究进展 ,对吸波原理、吸波材料的分类及特点进行了归纳分析和讨论 ,并对磁性金属纳米粒子用于雷达波吸收材料吸波机理和应用前景进行了展望     

低频雷达吸波材料的研究进展

随着米波、分米波低频雷达在军事领域的大规模应用,飞行器特别是远程战略轰炸机受到的空中威胁愈来愈大,为提高其生存能力,除对飞行器进行外形设计外,飞行器表面采用长波雷达吸波材料成为其隐身能力的关键措施之一.本文重点讨论了低频吸波机制,总结了传统吸波材料在低频下的应用,包括铁氧体、复合物、磁性金属微粉,分析了影响低频吸波性能...     

长链共轭席夫碱吸波材料的研究进展

阐述了长链共轭席夫碱吸波材料的吸波机理,综述了席夫碱吸波材料的电性能、磁性能、吸波性能的研究现状,展望了该类吸波材料的电性能、磁性能以及吸波性能的改善研究情况,可通过设计合成长链共轭结构的席夫碱、引进手性螺旋结构、利用过渡金属或稀土金属配位这3个方面来提高席夫碱吸波材料的电性能、磁性能以及吸波性能。     

雷达吸波材料低频化研究现状及进展

研发新型低频吸波材料成为突防多波段雷达的重要方面。重点讨论了低频雷达波吸波材料吸波性能的影响因素。针对低频吸波材料电磁参数要求,综述了当前重点研究和应用的低频吸波材料,包括铁氧体材料、磁性金属微粉材料等,以及各种微观形貌对低频吸波性能的影响,对进一步扩展低频吸波频带的发展进行了展望。     

碳纳米管吸波材料研究进展

介绍了碳纳米管的结构和性能特点,归纳和分析了碳纳米管吸波材料的最新进展,并提出了现有研究中存在的不足及进一步研究的方向。目前碳纳米管吸波材料的研究主要集中在不同结构碳纳米管吸波材料、磁性金属/碳纳米管复合吸波材料、稀土/碳纳米管复合吸波材料、铁氧体/碳纳米管复合吸波材料、聚合物/碳纳米管复合吸波材料以及陶瓷/碳纳米管复合吸波材料。对碳纳米管进行形貌控制、结构优化、表面修饰、复合掺杂改性以及界面结合和耐温性能的强化,是碳纳米管吸波材料今后的发展方向。     

纳米吸波材料研究进展

论述了纳米吸波材料种类、纳米吸波特性以及吸波原理,分别对纳米铁氧体吸波材料、金属纳米吸波材料、纳米氧化物吸波材料、纳米导电聚合物吸收剂以及纳米陶瓷吸波材料等材料吸波特性以及应用研究进展进行了重点分析和讨论,指出了具有宽频吸收的结构型纳米吸波复合材料是未来研究的重点和优先发展的方向。     

磁性金属吸波剂的高温氧化问题及其对策研究进展

目的 针对磁性金属吸波剂由组成元素化学性质活泼导致的高温氧化和电磁性能恶化问题展开现状调研和讨论,解析磁性金属吸波剂高温氧化的机理,并提出相应的解决策略。方法 从氧气在金属吸波剂中的吸附、反应和传质过程出发,讨论高温氧化对吸波剂电磁性能的影响规律,系统总结并评述表面包覆隔绝氧气、生成致密金属氧化膜和抑制氧原子扩散3种策略对吸波剂抗高温氧化的作用机制。结论 表面包覆策略通过引入有机高分子、无机化合物或磁性金属等包覆物质,以隔绝氧气,从而抑制磁性金属吸波剂的高温氧化。其中,无机化合物包覆体系最具潜力,但尚未达到理想的超薄致密状态。生成致密氧化膜策略通过溶质元素的选择性氧化,形成保护膜,能够有效抑制氧化进程,但引入较高含量的非铁磁性溶质元素容易降低磁导率、恶化吸波性能。抑制氧原子扩散策略通过形成晶界氧化物来有效减缓氧化,目前其实现手段有限且不够成熟。在耐温磁性吸波剂的研制中应综合考虑使用温度、基体材料、目标吸波频段和期望吸波性能等,采用合适的抗氧化策略。     

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.     

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.     

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.     

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)。