共查询到20条相似文献,搜索用时 31 毫秒
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In order to analyze the effect of varied doping structure on the quantum efficiency and spectrum response of the photocathode, six kinds of reflective varied doping GaN photocathode samples are designed and grown. The quantum efficiency curves and the spectrum response curves are obtained after these samples are activated. Through the analysis of experiment result, the factors and the reasons that can affect the quantum efficiency and spectrum response are concluded. The experiment result shows that the photocathode with exponential-doping structure has the best spectrum response and the highest quantum efficiency. The experiment result provides suggestions for the study on optimizing design of photocathode doping structure. 相似文献
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A numerical study is presented to show the potential for using vibroacoustic-based experiments to identify elastic material properties of orthotropic cylindrical vessels immersed in fluids. Sensitivity analyses and a simulated inverse problem are shown to quantify the potential for material characterization through the use of acoustic emissions. For comparison purposes, the analyses are also shown with the normal component of the velocity at the surface of the cylinder as the measured response in place of the acoustic pressure. The simulated experiment consisted of an orthotropic cylinder immersed in water with an impact force applied to the surface of the cylinder. The material parameters of the cylinder considered in the analyses were the circumferential and longitudinal elastic moduli, and the in-plane shear modulus. The velocity response is shown to provide sufficient information for characterizing all three moduli from a single experiment. Alternatively, the acoustic pressure response is shown to provide sufficient information for characterizing only the two elastic moduli from a single experiment. The analyses show that the acoustic pressure response does not have sufficient sensitivity to the in-plane shear modulus for characterization purposes. 相似文献
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J N van Dijkhuizen P C Anema R Plomp 《The Journal of the Acoustical Society of America》1987,81(2):465-469
Within the framework of a study on the merits of a frequency-dependent automatic gain control in hearing aids, the effect of varying the slope of the amplitude-frequency response on the speech-reception threshold (SRT) for sentences in noise was studied for normal-hearing listeners. Speech and noise were both subjected to the same amplitude-frequency response. In the first experiment, the effect of a constant slope was investigated (20 listeners). Over a range of about -7 to +10 dB/oct, the SRT in noise remained constant. In the second experiment, a single change in the slope of the amplitude-frequency response was introduced halfway through the sentence. The effect of varying the transition time over a range down to 0.125 s appeared to be very small. In the third experiment, the slope varied continuously with range and variation frequency (0.25-2 Hz) as the parameters. The masked SRT increased gradually with variation frequency. The results indicate that the masked SRT for sentences is remarkably resistant to dynamic variations in the slope of the amplitude-frequency response. 相似文献
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研究了有界波电磁脉冲模拟器下短线缆效应的理论建模和实验方法。基于传输线模型计算了线缆在有界波电磁脉冲模拟器辐照下的电流响应。建立了有界波电磁脉冲模拟试验环境,其前沿时间小于5 ns,脉冲半高宽约200 ns。开展了短线缆的效应实验验证研究,短线缆负载端响应电流的测量和计算结果吻合得很好,表明应用改型有界波电磁脉冲模拟器开展短线缆效应实验在理论和实验上都是可行的。这种线缆实验方法具有效应实验空间电磁场分布规范均匀、参数指标可控、监测技术成熟等优点。 相似文献
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Photomechanical actuation is demonstrated in two coupled liquid crystal elastomer photomechanical optical devices (PODs) acting in series. The response function of an individual POD is characterized and used to predict the temporal response of the coupled system. The predicted coupled-system response agrees with the experiment for several waveforms and frequencies, suggesting that large-scale integration of photomechanical devices is possible. 相似文献
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CT扫描系统中成像系统响应的不一致性对重建图像质量的影响 总被引:9,自引:2,他引:7
在 CT扫描系统中 ,成像系统响应的不一致性将导致所获取的投影中存在趋势项 ,这将引起 CT重建图像质量的下降。分析了成像系统响应不一致性产生的原因及其对 CT重建图像的影响 ,提出了不一致性校正方法 ,并通过实验进行了验证。 相似文献
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对三台单光子计数CCD的能量响应特性和探测效率进行实验标定。采用标准放射源对CCD进行照射,将CCD图像进行统计处理后,得到CCD的能量响应曲线。响应曲线近似为线性,不同的CCD响应曲线斜率明显不同。编写了MATLAB程序对多像素事件进行处理,获得CCD的探测效率曲线。在不同的能点处,CCD的探测效率明显不同,在5.1keV附近探测效率达到最大值。标定结果与XOP软件计算得到的吸收效率理论结果比较一致。该标定结果可用于超强激光打靶产生的Kα荧光光子产额和能谱的定量精确处理。 相似文献
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Trevor J. Cox 《Applied Acoustics》2008,69(12):1195-1204
Thirty-four horrible sounds have been examined in an Internet-based psychoacoustic experiment. This paper presents the results for the scraping and disgusting noises used. It is not understood why some humans find certain scraping noises, such as the sound of fingernails being scraped down a blackboard, so terrible. In this experiment, the variations in ratings with age, gender and location are examined. The results for one of the scraping sounds is consistent with the hypothesis suggested by others, that the response comes from a vestigial reflex related to the warning cries of monkeys. But this was not true for the actual recording of the fingernails scraping down a blackboard. An alternative hypothesis that the response is related to an audio-haptic interaction was tested and results indicated that this idea warrants further investigation. Other possible causes of the response, drawing on work concerning dissonance, are tentatively suggested. The disgusting sounds examined included the worst sound found in the experiment, the sound of someone vomiting. However, none of the disgusting sounds tested promoted responses consistent with a ‘disgust reaction’ based purely on survival instincts. Cultural factors might be important in our response to the disgusting sounds, with the influence of manners and etiquette being suggested as a possible factor. 相似文献
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激光诱导扩散中,当入射激光光强为高斯分布甚至均匀分布时,微小扩散区的温度分布不均匀。由于扩散系数是温度的函数,必将导致扩散后杂质浓度分布的均匀性较差,无法制作出高性能的p-n结。提出采用多次激光诱导扩散的积分效应来实现杂质浓度分布的均匀化整形。对于InP衬底的CO2激光诱导Zn扩散,利用温度闭环测控系统测得的基片表面热斑温度场分布,分析计算了两次激光诱导扩散重叠区域的浓度分布积分效应。在此基础上模拟计算出,用双次曝光积分效应做杂质浓度分布的均匀化整形时,基片上两次激光照射位置的最佳间隔为20 μm。这为改进激光诱导扩散工艺,用多次曝光实现面均匀的杂质浓度分布奠定了理论基础。 相似文献
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The theory used for examining the response of a structure subject to an external oscillatory force when certain structural parameters are changed is applied to the mathematical model of a pilot's seat structure. The results are discussed with a view to assessing those parts of the structure that are most effective in minimizing the response. Also, a laboratory experiment is described in which the basic circular response locus is verified, and doubts about the assumptions made in mathematical modelling resolved. 相似文献