The electrification of spacecraft

Physical and applied aspects of the electrification of space vehicles and natural celestial objects are discussed, the factors resulting in electrification of spacecraft are analyzed, and methods of investigating various phenomena associated with this electrification and ways of protecting spacecraft against the influence of static electricity are described. The booklet is intended for the general reader interested in present day questions of space technology

СЛУЧАЙНЫЕ ПРОЦЕССЫ ВОЗМУЩЕНИЯ В ДИНАМИКЕ РЕЛЬСОВЫХ ЭКИПАЖЕЙ

Previous works contained correlation and spectral  analysis of the four-dimensional  disturbance  process in the form of vertical and horizontal irregularities of left and right rails, causing oscillations in rail vehicles. But when speed increases, the disturbance frequency range shifts to high frequencies and can go beyond natural frequencies of the system. Then disturbance almost ceases to excite a part of vibration frequencies and obtained results will be incorrect.The article considers requirements to the procedure of computer generating a multidimensional stationary random disturbance process, causing vibrations of rail vehicles.  Using  modeling,  computer  simulation,  and mathematical analysis it is shown that when the speed alters it is necessary to change terms of the composition of the random process of geometrical irregularities of the  track.  The  requirements  for  parameters  of  the probabilistic analysis are determined, examples of generating and the results of spectral analysis of irregularities generated for different speeds are shown.В статье рассмотрены требования к процедуре генерации на ЭВМ многомерного стационарного случайного процесса возмущения, вызывающего колебания рельсовых экипажей. Показано, что при изменении скорости движения необходимо менять состав слагаемых случайного процесса геометрических неровностей рельсового пути. Определены требования к параметрам вероятностного анализа, приведены примеры генерации и результаты спектрального анализа случайных неровностей для различных скоростей движения

Selective Oxidation of 1,2-propane Glycol to Methylglyoxal: the Preparation of Ag/ZrO2 Catalysts by Biosynthesis Methods

丙酮醛（MGX）是一种重要的有机合成中间体，主要用作药物中间体，也广泛用于制备农药、食品添加剂等。丙酮醛通过与甲醛、氨等反应可以制得医药中间体4-甲基咪唑，还可以通过歧化反应制得用途广泛的乳酸。近年来随着咪唑以及呋喃酮等香料需求的增加，丙酮醛的需求量也日益增加，但它的天然存在量很少，而国内丙酮醛的生产起步晚，且规模较小。另外，丙酮醛的传统制备方法中所采用的催化剂多为电解银催化剂，电解银催化剂在反应温度低于500℃时活性不够，产物中有较多副产物羟基丙酮，而在高于500℃时，银微晶在高温条件下容易快速团聚导致催化活性下降。因此探索和深入研究在低温条件下具有高催化性能的催化剂，是丙酮醛实现经济、“绿...As an important organic intermediate, methylglyoxal(MGX) is mainly used as drug intermediates, and also has important applications in agricultural pesticide, food additives and so on. MGX can react with formaldehyde and ammonia to produce imidazole, which is a kind of drug intermediates. In addition, lactic acid can be produced by disproportionation reaction of MGX. Recently, the demand for MGX in...学位：工学硕士院系专业：化学化工学院化学工程与生物工程系_工业催化学号：2062007115090

Adiabatic description of nonspherical quantum dot models

Within the effective mass approximation an adiabatic description of spheroidal and dumbbell quantum dot models in the regime of strong dimensional quantization is presented using the expansion of the wave function in appropriate sets of single-parameter basis functions. The comparison is given and the peculiarities are considered for spectral and optical characteristics of the models with axially symmetric confining potentials depending on their geometric size making use of the total sets of exact and adiabatic quantum numbers in appropriate analytic approximations