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21.
利用一套罗斯滤片系统测量激光轰击固体金属Ti平面靶产生的X射线辐射通量,系统包括两个相同的X射线探测器及相应滤膜。罗斯滤片法的优点在于利用相邻核素对X射线相似的阻止率,可滤出一个窄的能带并去除高能部分的干扰,获得了Ti平面靶K壳层X光辐射产额。实验结果表明:硬X射线能段在4.5~4.9keV之间的K壳特征辐射占优,连续谱所占份额较低(与晶体谱仪一致);随着激光能量的增加,特征辐射增加;激光强度接近2×1015 W/cm2时,能量转换效率出现峰值。 相似文献
22.
彩色显示器上大色差的研究 总被引:1,自引:1,他引:1
在彩色显示器上新的主观色差评价实验表明:CIELUV颜色空间色差公式中彩度差的权重相对于明度差的权重而言显著偏高了. 相似文献
23.
实用的三维真彩色模压全息 总被引:2,自引:0,他引:2
三维真彩色模压全息图从艺术角度、信息量、技术含量和防伪功能均优于平面假彩色和平面真彩色模压全息图。本文分析了拍摄三维真彩色彩虹全息图的原理,给出了本方法实现实用三维真彩色模压全息的特点。 相似文献
24.
It has been demonstrated that the Filtered-x Wilcoxon LMS (FxWLMS) based adaptive filter mitigates the effect of the outliers acquired by the microphone signal of hearing aids by minimizing the Wilcoxon norm and hence shows better cancellation performance than the existing Filtered-x LMS (FxLMS) algorithm. The prediction error method based adaptive feedback canceller (PEMAFC) reduces the bias present in the estimate of the feedback path due to the continuous adaptive filtering (CAF). However, the impulse response of the measured feedback path is close to zero for the first many samples due to the delay introduced by ADC converters and then contains few significant values, which results in slow convergence rate when an adaptive filter is used to model the same. To overcome this limitation, we propose a proportionate normalized WLMS (PNWLMS) algorithm based PEMAFC (P-PNWLMS) for feedback cancellation in hearing aid in the presence of outliers. Further, with an objective to improve the convergence rate and performance accuracy simultaneously, this paper proposes a novel convex PNWLMS (CPNWLMS) algorithm which incorporates convex combination of PNWLMS and WLMS algorithms. The weight update equations are derived for PEMAFC trained by PNWLMS (P-PNWLMS) and CPNWLMS (P-CPNWLMS) algorithms respectively. The results of the simulation study show improved performance of the proposed CPNWLMS based adaptive filter over its component filters. 相似文献
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Weidong Gao Meiqiong Zhan Shuhai Fan Janda Shao Zheng-Xiu Fan 《Applied Surface Science》2005,250(1-4):195-202
The laser-induced damage (LID) behavior of narrow-band interference filters was investigated with a Nd:YAG laser at 1064 nm under single-pulse mode and free-running mode. The absorption measurement of such coatings was performed with surface thermal lensing (STL) technique. The damage morphologies under the two different laser modes were also studied in detail. It was found that all the filters exhibited a pass-band-center-dependent absorption and laser-induced damage threshold (LIDT) behavior, but the damage morphologies were diverse. The explanation was given with the analysis of the electric field distribution and the operational behavior of the irradiation laser. 相似文献
29.
Y. Uzawa M. Takeda A. Kawakami Z. Wang T. Noguchi 《International Journal of Infrared and Millimeter Waves》2005,26(1):41-54
We describe a novel method of designing a tuning circuit with two half-wave distributed junctions separated by a half-wavelength microstripline, which analytically determines the circuit parameters such as the minimum current density of the junctions and the characteristic impedances of the distributed junctions and the microstripline. The tuning circuit was approximated by simple transmission theory and then simplified with ideal circuit components for analysis. We applied Chebyshevs band-pass filter theory, in part, to optimize the circuit design. The analytical results revealed that a high characteristic-impedance ratio between the distributed junctions and the microstripline is necessary to obtain broadband matching using low-current-density junctions. The experimental results for all-NbN SIS mixers we designed with this method demonstrated double-sideband (DSB) receiver-noise temperatures of 6–10 quanta from 710 to 810 GHz for a mixer with a current density of only 4 kA/cm2 (estimated CJRN product of 37 at 750 GHz). The RF bandwidth was broader than that of a conventional full-wave distributed SIS mixer with the same current density. 相似文献
30.
The border luminance of the test stimulus between the natural and unnatural object color, yynBu was obtained for different spatial sizes of the immediate surround to prove that nBu can be determined based on a new recognized visual space of illumination (RVSI) that is assumed to be constructed for the immediate surround separately from the RVSI for the subjects room itself. The nBu of five test stimuli were determined for six different sizes covering from zero to 1866 cm2 with four different lightnesses, N4, N6 and N8, while keeping the room illuminance constant at 100 or 600 lx. The results showed that luminance of the border nBu gradually decreased as the size of the immediate surround was increased and that the decrease was larger for immediate surround with lower lightness. The results were interpreted as showing a new RVSI constructed for the spatial extent of the immediate surround of the test stimulus, and the RVSI was more completely constructed for larger spatial size of the immediate surround. © 2005 The Optical Society of Japan 相似文献