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Ba(Y_(1-x)Ce_x)_2Si_3O_(10)的光声光谱分析研究
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作者 赵鹏程 陈赵江 +1 位作者 左惟涵 方健文 《浙江师范大学学报(自然科学版)》 CAS 2013年第3期277-281,共5页
室温条件下测定了Ba(Y1-xCex)2Si3O10(x=0.05,0.07,0.09)的漫反射吸收光谱、光声振幅谱和光声相位谱.由于高浓度掺杂使得Ce3+与Ce3+之间发生有效能量传递,从而导致Ba(Y1-xCex)2Si3O10(x=0.05,0.07,0.09)的漫反射吸收光谱强度依次降低,... 室温条件下测定了Ba(Y1-xCex)2Si3O10(x=0.05,0.07,0.09)的漫反射吸收光谱、光声振幅谱和光声相位谱.由于高浓度掺杂使得Ce3+与Ce3+之间发生有效能量传递,从而导致Ba(Y1-xCex)2Si3O10(x=0.05,0.07,0.09)的漫反射吸收光谱强度依次降低,光声光谱强度依次增大.利用光声振幅谱结合相位谱的方法研究发光效率随掺杂浓度的变化,发现Ba(Y1-xCex)2Si3O10(x=0.05,0.07,0.09)3种不同掺杂浓度试样的发光效率依次降低. 展开更多
关键词 漫反射吸收 光声振幅谱 相位 吸收系数 效率
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SPEECH ENHANCEMENT USING CONSTRAINED SPECTRAL AMPLITUDE SUBTRACTION BASED ON NONCAUSAL A PRIORI SNR 被引量:3
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作者 Wu Hongwei Wu Zhenyang 《Journal of Electronics(China)》 2006年第6期937-942,共6页
Two gain forms of spectral amplitude subtraction are derived theoretically without neglecting the correlation of speech and noise spectrum during the period of a fralne. In the implementation, the constrained gain is ... Two gain forms of spectral amplitude subtraction are derived theoretically without neglecting the correlation of speech and noise spectrum during the period of a fralne. In the implementation, the constrained gain is expressed as a function of noncausal a priori SNR (Signal-to-Noise Ratio). Noise and noncausal a priori SNR are estimated from the multitaper spectrum of the noisy signal with algorithms modified to be suitable for the multitaper spectruln. Objective evaluations show that in case of white Gaussian noise the proposed method outperforms some methods based on LSA (Log Spectral Amplitude) in terms of MBSD (Modified Bark Spectral Distortion), segmental SNR and overall SNR, and informal listening tests show that speech reconstructed in this way has little speech distortion and musical noise is nearly inaudible even at low SNR. 展开更多
关键词 Speech cnhancement Spectral amplitude subtraction Noise estimation Multitaper spectrum
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