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1988年微波理论和技术分类提要:超速光学和微波技术
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作者 Lee,C 陈仪伟 《电光系统》 1989年第4期54-55,共2页
关键词 微波技术 超速光学 光学 微波
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超快速光学技术的发展
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作者 陈国夫 陈中仁 《激光与红外》 CAS CSCD 北大核心 1990年第5期1-3,共3页
本文简要介绍了超快速光学技术,特别是飞秒光脉冲和具有皮秒及飞秒时间分辨的诊断技术的国内外发展现状,指出了该技术在超快现象过程研究中的一些应用。
关键词 超速光学技术 光学 光电子学
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Determination the Vigor of Rice Seed with Different Degrees of Aging with Ultraweak Chemiluminescence During Early Imbibition 被引量:12
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作者 陈文利 邢达 何永红 《Acta Botanica Sinica》 CSCD 2002年第11期1376-1379,共4页
用高灵敏度的单光子计数系统探测人工老化 (40℃ ,相对湿度 90 % ) 0、7、14和 2 1d的水稻种子吸胀初期的超弱化学发光强度变化 ,首次观测到水稻 (OryzasativaL .)种子吸胀初期超弱化学发光强度与其老化程度有关。加水激活水稻种子的超... 用高灵敏度的单光子计数系统探测人工老化 (40℃ ,相对湿度 90 % ) 0、7、14和 2 1d的水稻种子吸胀初期的超弱化学发光强度变化 ,首次观测到水稻 (OryzasativaL .)种子吸胀初期超弱化学发光强度与其老化程度有关。加水激活水稻种子的超弱化学发光 ,其强度依赖于种子的老化程度。实验结果表明水稻种子的人工老化时间越短 ,则吸胀初期 (2 0~ 30min)超弱化学发光的强度越强 ,萌发率越高。水稻种子萌发率与超弱化学发光强度呈显著正相关。观测水稻种子吸胀初期超弱化学发光强度的变化可望成为检测种子老化程度的一种快速、简便、无损伤的新方法。 展开更多
关键词 rice seeds ultraweak chemiluminescence early imbibition accelerated aging
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Subluminal and Superluminal Phenomena in a Four-Level Atom 被引量:1
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作者 HAN Ding-An ZENG Ya-Guang CAO Hui 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第7期197-200,共4页
In a four-level atomic system, we investigate the light pulse propagation properties interacting with only one laser field. It is shown that in the steady state, the group velocity of the light pulse can be changed fr... In a four-level atomic system, we investigate the light pulse propagation properties interacting with only one laser field. It is shown that in the steady state, the group velocity of the light pulse can be changed from subluminal to superluminal by varying the field detuning. Meanwhile, the effects of the field intensity on the group velocity are also shown. At last, with special parameters, the analytical solution for the group index is also obtained. 展开更多
关键词 SUPERLUMINAL SUBLUMINAL
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Ignition, flame propagation and extinction in the supersonic mixing layer flow 被引量:7
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作者 ZHANG YunLong WANG Bing ZHANG HuiQiang 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第11期2256-2264,共9页
The supersonic mixing layer flow,consisting of a relatively cold,slow diluted hydrogen stream and a hot,faster air stream,is numerically simulated with detailed transport properties and chemical reaction mechanisms.Th... The supersonic mixing layer flow,consisting of a relatively cold,slow diluted hydrogen stream and a hot,faster air stream,is numerically simulated with detailed transport properties and chemical reaction mechanisms.The evolution of the combustion process in the supersonic reacting mixing layer is observed and unsteady phenomena of ignition,flame propagation and extinction are successfully captured.The ignition usually takes place at the air stream side of braid regions between two vortexes due to much higher temperature of premixed gases.After ignition,the flame propagates towards two vortexes respectively located on the upstream and downstream of the ignition position.The apparent flame speed is 1569.97 m/s,which is much higher than the laminar flame speed,resulting from the effects of expansion,turbulence,vortex stretching and consecutive ignition.After the flame arrives at the former vortex,the flame propagates along the outer region of the vortex in two branches.Then the upper flame branch close to fuel streamside distinguishes gradually due to too fuel-riched premixed mixtures in the front of the flame and the strong cooling effect of the adjacent cool fuel flow,while the lower flame branch continues to propagate in the vortex. 展开更多
关键词 supersonic mixing layer IGNITION flame propagation EXTINCTION
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Investigation of the Compressible Flow through the Tip-Section Turbine Blade Cascade with Supersonic Inlet 被引量:2
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作者 Martin Luxa Jaromír Príhoda +2 位作者 David Simurda Petr Straka Jaroslav Synác 《Journal of Thermal Science》 SCIE EI CAS CSCD 2016年第2期138-144,共7页
The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(int... The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade. 展开更多
关键词 long turbine rotor blade supersonic tip section optical methods transition modelling CFD
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Measurement of Supersonic Jet Noise with Optical Wave Microphone System
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作者 Masataka KOSAKA Kunisato SETO +1 位作者 MD.Tawhidul Islam KHAN Yoichi NAKAZONO 《Journal of Thermal Science》 SCIE EI CAS CSCD 2005年第4期352-356,共5页
An optical wave microphone system is a new technique of sound measurement. This technique has been developed as a new plasma diagnostic technique to measure electron density fluctuations in the nuclear fusion research... An optical wave microphone system is a new technique of sound measurement. This technique has been developed as a new plasma diagnostic technique to measure electron density fluctuations in the nuclear fusion research. Because the sound wave is a pressure or a density fluctuation, it is possible for this technique to measure the sound wave, too. The acoustical characteristics of the optical wave microphone system were examined by using a speaker as a first step. Next, feasibility of this device to measure jet noise was examined. It was found that the optical wave microphone system could measure the jet noise as well as a sound from speaker. Hence the optical wave microphone system can be considered one of the devices equivalent to condenser microphone. Because of these reason, this device is very convenient to scan the acoustic filed through jet flow from the inside to the out side and more preferable for not disturbing the observation field. 展开更多
关键词 supersonic jet laser sound measurement optical wave microphone system.
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A three-equation turbulence model for high-speed flows 被引量:1
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作者 LIU JingYuan 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第4期803-811,共9页
Adding a new equation to the two-equation K-turbulence model framework,this paper proposed a three-equation turbulence model to determine the density variance for high-speed aero-optics and high-speed compressible tur... Adding a new equation to the two-equation K-turbulence model framework,this paper proposed a three-equation turbulence model to determine the density variance for high-speed aero-optics and high-speed compressible turbulent flows.Simulations were performed with the new model for supersonic and hypersonic flat-plate turbulent boundary layer and hypersonic ramp flows.The results showed that the prediction with the present model agrees well with the experimental data and is significantly better than the Lutz's model in predicting the density variance for the flat-plate flows.Furthermore,the present model can produce more accurate skin pressure and skin heat flux distributions than the original K-model in simulating hypersonic compression ramp flows with separation and reattachment and shock/boundary layer interactions.Without introducing a variety of ad hoc wall damping and wall-reflection terms,the proposed three-equation turbulence model is applicable to highspeed aero-optics and turbulent flows of real vehicles of complex configuration. 展开更多
关键词 high speed turbulence model density variance AERO-OPTICS numerical simulation heat flux SEPARATION
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Photofragment translational spectroscopy of ICl near 304 and 280 nm: Observation of an intense hot band effect
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作者 CHENG Min YU ZiJun +3 位作者 XU XiLing YU Dan DU YiKui ZHU QiHe 《Science China Chemistry》 SCIE EI CAS 2012年第6期1148-1154,共7页
The photodissociation dynamics of IC1 has been studied near 304 and 280 nm on a simple miniature time of flight (mini-TOF) photofragment translational spectrometer with a short pulse of a weak acceleration field. An i... The photodissociation dynamics of IC1 has been studied near 304 and 280 nm on a simple miniature time of flight (mini-TOF) photofragment translational spectrometer with a short pulse of a weak acceleration field. An intense hot band effect was ob- served. Many small peaks were resolved in each photofragment translational spectrum (PTS). Based on simulations, the principal peaks were assigned not only to the different photodissociation channels (1) I + C1, (2) I + CI*, (3) I* + C1, or (4) I* + CI*, but also to the different chlorine isotopes (35C1 and 37C1). Moreover, some extra peaks showed the existence of an intense hot band effect from vibrationally excited ICI molecules, though only a few percent of ICI molecules remained in the vibrationally excited states in our supersonic molecular beam. Based on the spectra near 304nm, the quantum yield Φ of each channel, the curve crossing, and the branching fraction a from each transition state were determined. 展开更多
关键词 photofragment translational spectroscopy ICL PHOTODISSOCIATION hot band
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Effects of Compressibility and Knudsen Number on the Aero Optics in Hypersonic Flow Fields 被引量:4
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作者 任维 刘洪 《Journal of Shanghai Jiaotong university(Science)》 EI 2016年第3期270-279,共10页
Tsien summarized the similarity in hypersonic flows, and related Knudsen number to Mach number and Reynolds number. Recently, a path-based problem, aero-optical effect, arises in hypersonic flows, and it concerns abou... Tsien summarized the similarity in hypersonic flows, and related Knudsen number to Mach number and Reynolds number. Recently, a path-based problem, aero-optical effect, arises in hypersonic flows, and it concerns about the compressibility and the Knudsen number of the gas flows, which differs from the Tsien's focus to some extent. In this paper, the similarity of hypersonic aero optics is theoretically studied, and both flow fields and induced aero-optical effect after flows pass through a cylinder are predicted by a well-accepted particle-based method, direct simulation Monte-Carlo(DSMC) method. The results show that the optical distortions are inversely proportional to the Knudsen number, while the compressibility plays an important role in the optical degradations.Hence, it is confirmed that the effects of Mach number and Knudsen number on the aero-optical effect induced by hypersonic flows are of great significance. Besides, since the Knudsen number is defined straightforwardly based on the optically active region, the physics is clearer than any other similarity criteria. 展开更多
关键词 aero optics hypersonic flows similarity Knudsen number
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