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71.
宣钢l260m^3高炉大修改造时将炉容扩大到l350m^3,对高炉本体系统设备及冷却系统、自动控制及检测系统进行了全面的改造更新,在炉腹、炉腰及炉身下部高热负荷区域采用铜冷却壁,取消炉身中上部铸铁冷却壁凸台,并采用薄内衬等先进、适用、可靠、成熟的技术。  相似文献   
72.
We have studied the reflectivity spectra of doped GaAs nanowhiskers (NWs) with various morphologies, which were grown by molecular-beam epitaxy. It is established that the character of the reflectivity spectra of NWs is determined by the shape of nanocrystals. NWs with droplike and pointlike vertices differently interact with electromagnetic radiation. Laser radiation produces a spectraly selective action on the NW array, which leads to a change in the NW height and induces “caking” of their vertices, thus modifying the reflectivity of the sample. This phenomenon can be used for the creation of local microstructures with preset characteristics in large NW arrays.  相似文献   
73.
Electromechanical properties of the 0-0-2-2 type composite based on platelike crystals of solid solutions of ferroelectric relaxors of the Pb(A1/3Nb2/3)O3-PbTiO3 system (A = Zn, Mg) have been studied for the first time. Factors accounting for the record values of some effective parameters of this composite are considered. The relationship between the components of the elastic compliance tensor of the layered structures forming the composite and the positions of maxima of the effective hydrostatic parameters is established.  相似文献   
74.
75.
Expressions describing the threshold sensitivity of a quantum converter of IR radiation into visible light are obtained for two schemes of energy levels in the active atoms. Based on these expressions, practical criteria for the creation of such devices are formulated.  相似文献   
76.
The effect of pulsed photon annealing with energy densities from 1.4 to 42 J/cm2 for various lengths of time on the structure of the amorphous alloy Fe79P14.2Si4.4Mn2.2V0.2 was studied by x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy. The results demonstrate that short-term irradiation with low energy densities leads to surface relaxation of the amorphous alloy, increases the strength of the surface layer, and reduces the internal-friction peak. Longer term photon annealing leads to crystallization of the alloy throughout the sample thickness.  相似文献   
77.
78.
The results of observations performed over many years are used to make an assessment of the degree to which the concentration of chemical and radioactive substances escaping into the environment during salvaging of nuclear-powered submarines exceeds the admissable norms for workers at the main ship-repair facilities in Russia and for the general public in the surrounding territories. It is shown that the chemical substances are a determining factor in environmental contamination. Their content in the atmosphere and sea water exceeds the admissable norms near sources, on the territory of the enterprises, and (for individual indicators) at populated points. Under these conditions, the concentration of technogenic radionuclides does not exceed the admissable norms and its damaging effect on man is hundreds and thousands of times less than that of chemicals.  相似文献   
79.
Special features of fracture of structural steels 45N2D2M and 45N4D2M manufactured by pressing with subsequent sintering from partially alloyed iron powders are studied. Impact bending tests of specimens with different levels of retained porosity show two kinds of fracture, i.e., intraparticle cleavage and interparticle dimple fracture. In addition, the surfaces of the “initial” pores come out to the fracture surface. Other conditions being equal, growth in porosity decreases the proportion of the brittle component of fracture and decreases the critical brittle point.  相似文献   
80.
精选了一系列有机和无机化合物为成核剂,使用砂浴法和热台法制备了一系列不同β晶含量的等规聚丙烯,发现最有效的β成核剂是溶靛素灰 IBL 和溶蒽素金黄 IGK,首次表明β成核剂具有排列紧密的稠球结构特征,且含有硫原子。  相似文献   
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