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991.
Chirped-pulse amplification system based on chirp reversal in optical parametric chirped-pulse amplification is proposed and experimentally demonstrated. The operation of this system can be described as negative stretching-temporal chirp reversal-energy amplification-negative compression, in which the pulse is stretched and compressed with the same gratings. Stand-alone stretcher adopting lenses or concave mirrors with large aperture can be omitted. Simulations showed that this work mode can also increase the cut-off band-pass of the whole system and increase the output energy by 15-17%. In addition, the stability of a tiled-grating compressor can be improved with this work mode. 相似文献
992.
Microcrystalline silicon (μc-Si) films were deposited at a high rate and low temperature using jet-type inductively coupled plasma chemical vapor deposition (jet-ICPCVD), and the deposition rate, microstructure and electrical properties of the deposited films were investigated. It was demonstrated that a high deposition rate of over 20 nm/s can be achieved while maintaining high crystallinity and low dark conductivity. The deposition rate is well controlled by regulating the generation rate and transport of growth precursors. High crystallinity of the films results principally from hydrogen-induced chemical annealing. Furthermore, the excellent electrical properties benefit from the low oxygen content and/or low deposition temperature. 相似文献
993.
本文从六个方面论述了技术管理在煤矿安全生产工作中的重要性,指出技术管理是安全生产的重要组成部分,它决定着煤矿开拓与开采方案设计的合理性。在安全隐患的查处和治理方面,技术管理同样至关重要。煤炭生产企业必须重视科学与技术,让技术管理成为企业发展的动力。同时,以人为本的技术管理是保证企业可持续发展的重中之重。 相似文献
994.
995.
Xiu-li Zuo Bin Xiang Xing Li Zi-dong Wei 《Journal of Materials Engineering and Performance》2012,21(4):524-529
Effects of pH value, chloride ion concentration and alternation of wetting and drying time in acid rain on the corrosion of
35CrMn and Q235 steel were investigated through the measurement of polarization curves, electrochemical impedance spectroscopy,
x-ray diffraction, and quantum mechanical calculations. The corrosion rate of 35CrMn and Q235 steel increased with decreasing
pH values of the simulated acid rain, whereas the corrosion potential of 35CrMn and Q235 steel became more negative. The impedance
became higher and the corrosion rate decreased with increasing test time. The dissolution rate of samples increased with chloride
ion concentration. Results suggested that the corrosion rate of 35CrMn steel was obviously lower than that of Q235 steel for
a more compact rust, α-FeOOH. Quantum chemical calculations further revealed that the increase in corrosion rate of the steel
resulted from pitting corrosion caused by the corrosive chloride ion. 相似文献
996.
Hongwei Guo Buxin Su Jianliang Zhang Jiugang Shao Haibin Zuo Shan Ren 《JOM Journal of the Minerals, Metals and Materials Society》2012,64(8):1002-1010
Due to the lack of knowledge regarding the combustion of granular coal injected into a blast furnace, injection characteristics of granular coal were first studied through proximate analysis, element analysis, and research of explosivity, ignition point, meltability of ash, grindability, calorific value, etc. Using a sampling device in the raceway combined with petrographic analysis, during the combustion process of granular coal with high crystal water and volatile in raceway, cracks and bursts were found, leading to a reduction of particle size. Based on a model of mass control and dynamic theory of particle combustion, the transition dynamic model for cracking in combustion of granular coal was found, and the critical value of cracking ratio (ΩP) for granular coal combustion in the raceway was calculated. Finally, the utilization ratio and energy efficiency of granular coal used in the blast furnace were discussed, offering theoretical foundation and technical support for intensifying granular coal combustion and promoting granular coal injection. 相似文献
997.
氧化铝基陶瓷型芯的可溶性是影响型芯应用于制造高性能燃机叶片的关键。研究了孔隙率对氧化铝基陶瓷型芯性能影响的规律。结果表明,型芯的溶失过程主要是莫来石相的溶失;型芯溶失性随着孔隙率的增加呈先增加后趋于稳定的变化规律,型芯强度则逐渐下降。当孔隙率为41.8%时溶失速率可达7.6mg/min,室温抗折强度超过14MPa;单次碱煮时间不宜超过4h。 相似文献
998.
直接频率合成技术为目前各种不同类型信号源设计的主要技术,本设计以QuartusⅡ为开发环境,利用VHDL语言,完成了正弦信号源的前端设计。并在CycloneⅡ系列EP2C35芯片上,不扩展外部存储器,时钟频率为40MHz的情况下,单片实现了频率步进为78Hz.频率范围为78Hz-1.25MHz的正弦信号源。 相似文献
999.
A new epoxy resin containing both binaphthyl and biphenyl moieties in the skeleton (BLBPE) was synthesized and confirmed by electrospray ionization mass spectroscopy, 1H‐nuclear magnetic resonance spectroscopy, and infrared spectroscopy. To evaluate the combined influence of two moieties, one epoxy resin containing binaphthyl moiety and another containing biphenyl moiety were also synthesized, and a commercial biphenyl‐type epoxy resin (CER3000L) was introduced. Thermal properties of their cured polymers with phenol p‐xylene resins were characterized by differential scanning calorimetry, dynamic mechanical, and thermogravimetric analyses. The cured polymer obtained from BLBPE showed remarkably higher glass transition temperature and lower moisture absorption, as well as comprehensively excellent thermal stability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
1000.