本文在验证了光声效应实验的可行性和正确性的基础上,逐一通过改变某一个变量来探究影响光声效应的因素,并利用Cool Edit Pro V2.1等声音分析软件将产生的声音收录起来进行定量的测量,分析影响光声效应实验产生声音音量和频率和相关影...本文在验证了光声效应实验的可行性和正确性的基础上,逐一通过改变某一个变量来探究影响光声效应的因素,并利用Cool Edit Pro V2.1等声音分析软件将产生的声音收录起来进行定量的测量,分析影响光声效应实验产生声音音量和频率和相关影响因素的关系。同时,设计光声信号产生装置,并搭建了光声信号测量系统,进而对该装置进行了进一步研究,最终设计出了基于光声效应的"光琴"演示装置。展开更多
This paper deals with internally generated noise of bioelectric amplifiers that are usually used for processing of bioelectric events. The main purpose of this paper is to present a procedure for analysis of the effec...This paper deals with internally generated noise of bioelectric amplifiers that are usually used for processing of bioelectric events. The main purpose of this paper is to present a procedure for analysis of the effects of internal noise generated by the active circuits and to evaluate the output noise of the author's new designed bioelectric amplifier that caused by internal effects to the amplifier circuit itself in order to compare it with the noise generated by conventional amplifiers. The obtained analysis results of internally generated noise showed that the total output noise of bioelectric active circuits does not increase when some of their resistors have a larger value. This behavior is caused by the different transfer functions for the signal and the respective noise sources associated with these resistors. Moreover, the new designed bioelectric amplifier has an output noise less than that for conventional amplifiers. The obtained analysis results were also experimentally verified and the final conclusions were drawn.展开更多
Thermoacoustically-driven pulse tube cooler can provide cryogenic cooling power with no moving com-ponents. Up to now, pulse tube cooler is directly coupled with the thermoacoustic engine and obtainable pressure ratio...Thermoacoustically-driven pulse tube cooler can provide cryogenic cooling power with no moving com-ponents. Up to now, pulse tube cooler is directly coupled with the thermoacoustic engine and obtainable pressure ratio for the pulse tube cooler is limited by the capability of the ther-moacoustic engine. The authors propose here the concept of acoustic amplifier, which is actually a long tube connecting the engine with the pulse tube cooler. Theoretical calculation shows that suitable length and diameter of the tube can lead to a pressure wave amplification effect which means that pressure wave amplitude coming from the thermoacoustic engine can be much amplified to drive the pulse tube cooler. Based on this, a 2.8 m long copper tube with 8 mm inner diameter is used as the acoustic amplifier in experiments. The experimental results show that due to the amplification effect, pressure wave amplitude at the inlet of the pulse tube cooler is over 2.5 times of that at the engine outlet. Typically, with 1.67 kW heating power, the pressure ratio provided by the engine is 1.11 while at the inlet of the pulse tube cooler the pressure ratio is 1.32, which leads to a lowest no-load temperature of 65.7 K.展开更多
A prototype of hybrid neural recording interface has been developed for extracellular neural recording. It consists of a silicon-based plane microelectrode array and a CMOS low noise neural amplifier chip. The neural ...A prototype of hybrid neural recording interface has been developed for extracellular neural recording. It consists of a silicon-based plane microelectrode array and a CMOS low noise neural amplifier chip. The neural amplifier chip is designed and implemented in 0.18 μm N-well CMOS 1P6M technology. The area of the neural preamplifier is only 0.042 mm2 with a gain of 48.3 dB. The input equivalent noise is 4.73 btVrms within pass bands of 4 kHz. To avoid cable tethering for high dense mul- tichannel neural recording interface and make it compact, flip-chip bonding is used to integrate the preamplifier chip and the microelectrode together. The hybrid device measures 3 mm×5.5 mm×330μm, which is convenient for implant or in-vivo neu- ral recording. The hybrid device was testified in in-vivo experiment. Neural signals were recorded from hippocampus region of anesthetized Sprague Dawley rats successfully.展开更多
文摘本文在验证了光声效应实验的可行性和正确性的基础上,逐一通过改变某一个变量来探究影响光声效应的因素,并利用Cool Edit Pro V2.1等声音分析软件将产生的声音收录起来进行定量的测量,分析影响光声效应实验产生声音音量和频率和相关影响因素的关系。同时,设计光声信号产生装置,并搭建了光声信号测量系统,进而对该装置进行了进一步研究,最终设计出了基于光声效应的"光琴"演示装置。
文摘This paper deals with internally generated noise of bioelectric amplifiers that are usually used for processing of bioelectric events. The main purpose of this paper is to present a procedure for analysis of the effects of internal noise generated by the active circuits and to evaluate the output noise of the author's new designed bioelectric amplifier that caused by internal effects to the amplifier circuit itself in order to compare it with the noise generated by conventional amplifiers. The obtained analysis results of internally generated noise showed that the total output noise of bioelectric active circuits does not increase when some of their resistors have a larger value. This behavior is caused by the different transfer functions for the signal and the respective noise sources associated with these resistors. Moreover, the new designed bioelectric amplifier has an output noise less than that for conventional amplifiers. The obtained analysis results were also experimentally verified and the final conclusions were drawn.
基金supported by the Chinese Academy of Sciences(Project Number:KJCX2-SW-W12-l).
文摘Thermoacoustically-driven pulse tube cooler can provide cryogenic cooling power with no moving com-ponents. Up to now, pulse tube cooler is directly coupled with the thermoacoustic engine and obtainable pressure ratio for the pulse tube cooler is limited by the capability of the ther-moacoustic engine. The authors propose here the concept of acoustic amplifier, which is actually a long tube connecting the engine with the pulse tube cooler. Theoretical calculation shows that suitable length and diameter of the tube can lead to a pressure wave amplification effect which means that pressure wave amplitude coming from the thermoacoustic engine can be much amplified to drive the pulse tube cooler. Based on this, a 2.8 m long copper tube with 8 mm inner diameter is used as the acoustic amplifier in experiments. The experimental results show that due to the amplification effect, pressure wave amplitude at the inlet of the pulse tube cooler is over 2.5 times of that at the engine outlet. Typically, with 1.67 kW heating power, the pressure ratio provided by the engine is 1.11 while at the inlet of the pulse tube cooler the pressure ratio is 1.32, which leads to a lowest no-load temperature of 65.7 K.
基金supported in part by the National Natural Science Foundation of China(Grant Nos.61076023,61275200,31070965)the National Basic Research Program of China("973" project)(Grant No.2011CB933203)the National High-Tech Research and Development Program of China("863" Project)(Grant No.2012AA030308)
文摘A prototype of hybrid neural recording interface has been developed for extracellular neural recording. It consists of a silicon-based plane microelectrode array and a CMOS low noise neural amplifier chip. The neural amplifier chip is designed and implemented in 0.18 μm N-well CMOS 1P6M technology. The area of the neural preamplifier is only 0.042 mm2 with a gain of 48.3 dB. The input equivalent noise is 4.73 btVrms within pass bands of 4 kHz. To avoid cable tethering for high dense mul- tichannel neural recording interface and make it compact, flip-chip bonding is used to integrate the preamplifier chip and the microelectrode together. The hybrid device measures 3 mm×5.5 mm×330μm, which is convenient for implant or in-vivo neu- ral recording. The hybrid device was testified in in-vivo experiment. Neural signals were recorded from hippocampus region of anesthetized Sprague Dawley rats successfully.
