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51.
The deformation behavior of dispersion strengthened copper alloy Cu-Al2O3 was studied by TEM. The results show that nano-scaled dispersed second phase not only increases dislocation density in matrix, but also has an important influence on the dislocation substructure. The presence of fine dispersed Al2 O3 particles results in a uniform and random dislocation distribution in matrix copper and causes the difficulty in formation of dislocation cell structure and the decrease in the amount of cell structure during deformation. Deformation gives rise to much more dislocations and dislocation cells form more difficultly and the decrease in the cell size with the increase of dispersion degree. 相似文献
52.
试论当代大学生IT素质的培养 总被引:1,自引:0,他引:1
成立 《徐州建筑职业技术学院学报》2005,5(2):57-60
从IT素质的涵义出发,论述了IT素质的涵盖内容、培养大学生IT素质的重要性以及IT素质的本质与特点.对高校树立人才培养新理念、培养优秀IT人才提出了有关建议及应对措施。 相似文献
53.
A high-density gas jet supersonic nozzle is reported in this paper. The jitter and actuation time of the nozzle is determined by the pin discharge and laser spark radiation respectively. The jitter time of the nozzle is within 10μs with the backing pressure as high as 25 bar. With a nanosecond laser pulse focused on the gas jet about 1 mm below the nozzle, the actuation time is calculated to be about 15 ms by detecting the laser produced spark radiation, which reveals the existence of the gas jet and the relative gas density evolving with time. Consequently the gas density is estimated to be well above 10^19 cm^-3, compared with theoretical simulations from the nozzle parameters. 相似文献
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CHENG Xiang 《半导体光子学与技术》2004,(4)
Amorphous carbon (a-C) films and amorphous carbon films incorporating with the nitrogen (a-C∶N) were deposited on silicon substrates in a radio-frequency driven plasma enhanced chemical vapour deposition system, while the surface electrical properties of films were investigated by electrochemical capacitance-voltage measurements. It was examined the effect of the interface defects on the properties and deduced that the conducting type of a-C∶N films was n-type. Subsequently, a comparative studies of a-C and a-C∶N films were performed by photoluminescence spectra depending on the temperature. With the decrease of the temperature, the main band with peak energy of 2.48 eV in the a-C∶N films was more intense compared with the other three bands caused by amorphous C in the a-C films. 相似文献
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The Three Gorges Project is a very large project,and its structure is very complex.Interna-tional advanced engineering equipment is broadly used.The state of equipment running directly influ-ences project building qualities and limited time.According to the factud conditions of the Three Gor-ges Project,the characteristics of engineering equipment are analyzed.At the same time ,some theories about equipment management are induced ,and the TDCPR management mode of engineering equip-ment of the Three Gorges Project is put forwared in order to gain the aim of managing and using equip-ment well and speeding up the project construction. 相似文献
60.
ChangLIU HuimingCHENG 《材料科学技术学报》2002,18(2):124-126
Single=walled carbon nanotubes(SWNTs) were synthesized by a hydrogen arc discharge method.A high yield of gram quantity of SWNTs per hour was achieved.Tow kinds of SWNT products:web-like substancea and thin films in large slices were obtained. Results of resonant Raman scattering measurements indicate that the SWNTs prepared have a wider diameter distribution and a larger mean diameter.Hydrogen uptake measurements of the two kinds of SWNT samples(both as prepared and pretreated) were carried out using a high pressure volumetric method,respectively.And a hydrogen storage capacity of 4 wt pct could be repeatedly achieved for the suitably pretreated SWMNTs,whicb indicates that SWNTs may be a promising hydrogen storge material. 相似文献