A monolithic integrated CMOS preamplifier is presented for neural recording applications. Two AC-coupied capacitors are used to eliminate the large and random DC offsets existing in the electrode-electrolyte interface...A monolithic integrated CMOS preamplifier is presented for neural recording applications. Two AC-coupied capacitors are used to eliminate the large and random DC offsets existing in the electrode-electrolyte interface. Diode-connected nMOS transistors with a negative voltage between the gate and source are candidates for the large resistors necessary for the preamplifier. A novel analysis is given to determine the noise power spectral density. Simulation results show that the two-stage CMOS preamplifier in a closed-loop capacitive feedback configuration provides an AC in-band gain of 38.8dB,a DC gain of 0,and an input-referred noise of 277nVmax, integrated from 0. 1Hz to 1kHz. The preamplifier can eliminate the DC offset voltage and has low input-referred noise by novel circuit configuration and theoretical analysis.展开更多
The welding fume has significant effects on the weld workers＇ health. In order to overwhelm the shortcomings of the control measures of the welding fume, the research of the purifying of welding fume on the spot was ...The welding fume has significant effects on the weld workers＇ health. In order to overwhelm the shortcomings of the control measures of the welding fume, the research of the purifying of welding fume on the spot was carried out. The purifying device was designed. The relationship between the corona discharge voltage and the purifying efficiency was investigated through experiments with different needle electrode numbers, different ring electrode numbers and different needle-plate distances. The results show that 5-needle double-ring electrode has the best efficiency; the purifying efficiency is increase with the lessening of the needle-plate distance and the increase of the discharge voltage. Using 5-needle double-ring electrode, the purifying efficiency reaches its maximum value 97.9% while the needle-plate distance is 6 cm, the discharge voltage is -35 kV. The purifying device has an excellent purifying effect on the welding fume.展开更多
The results of the assessment of the influence of paper insulation on the discharge initiation in oil were presented in this paper. This assessment based on the results of performed experimental works and on the analy...The results of the assessment of the influence of paper insulation on the discharge initiation in oil were presented in this paper. This assessment based on the results of performed experimental works and on the analysis of electrical field distribution. Both types of the studies were connected with the model HV （high voltage） electrode setups covered by paper and immersed in oil. Experimental works indicated that the source of ＂weak points＂ of paper-oil model electrode setup is oil, not the surface of metal or insulation wrapping. Such hypothesis, resulting mainly from the measured times to initiations of discharges developing from bare and insulated HV electrodes, was verified by the analysis of electrical field distribution performed on the basis of finite element method applied in the COMSOL Multiphysics software. This analysis confirmed preliminary the made hypothesis. Correlation with the most stressed oil volume law was also observed.展开更多
The investigation on the cathode material of potassium ion batteries(PIBs),one of the most promising alternatives to lithium ion batteries,is of great significance.Potassium vanadium fluorophosphate(KVPO4F)with a high...The investigation on the cathode material of potassium ion batteries(PIBs),one of the most promising alternatives to lithium ion batteries,is of great significance.Potassium vanadium fluorophosphate(KVPO4F)with a high working voltage is an appealing cathode candidate for PIBs,while the poor cycling performance and low electronic conductivity dramatically hinder the application.Herein,a plum pudding model inspired three-dimensional amorphous carbon network modified KVPO4F composite(KVPO4F@3DC)is successfully designed in this study to tackle these problems.In the composite,KVPO4F particles are homogeneously wrapped by a layer of amorphous carbon and bridged by crosslinked large area carbon sheets.As the cathode for PIBs,the KVPO4F@3DC composite exhibits a high average operating voltage about 4.10 V with a super-high discharge capacity of 102.96 mAh g^-1 at 20 mA g^-1.An excellent long cycle stability with a capacity retention of 85.4%over 550 cycles at 500 mA g^-1 is achieved.In addition,it maintains 83.6%of its initial capacity at 50 mA g^-1 after 100 cycles at 55℃.The design of KVPO4F@3DC with plum pudding structure provides facilitative electron conductive network and stable electrode/electrode interface for electrode,successfully innovating an ultra-stable and high-performance cathode material for potassium ion batteries.展开更多
文摘A monolithic integrated CMOS preamplifier is presented for neural recording applications. Two AC-coupied capacitors are used to eliminate the large and random DC offsets existing in the electrode-electrolyte interface. Diode-connected nMOS transistors with a negative voltage between the gate and source are candidates for the large resistors necessary for the preamplifier. A novel analysis is given to determine the noise power spectral density. Simulation results show that the two-stage CMOS preamplifier in a closed-loop capacitive feedback configuration provides an AC in-band gain of 38.8dB,a DC gain of 0,and an input-referred noise of 277nVmax, integrated from 0. 1Hz to 1kHz. The preamplifier can eliminate the DC offset voltage and has low input-referred noise by novel circuit configuration and theoretical analysis.
文摘The welding fume has significant effects on the weld workers＇ health. In order to overwhelm the shortcomings of the control measures of the welding fume, the research of the purifying of welding fume on the spot was carried out. The purifying device was designed. The relationship between the corona discharge voltage and the purifying efficiency was investigated through experiments with different needle electrode numbers, different ring electrode numbers and different needle-plate distances. The results show that 5-needle double-ring electrode has the best efficiency; the purifying efficiency is increase with the lessening of the needle-plate distance and the increase of the discharge voltage. Using 5-needle double-ring electrode, the purifying efficiency reaches its maximum value 97.9% while the needle-plate distance is 6 cm, the discharge voltage is -35 kV. The purifying device has an excellent purifying effect on the welding fume.
文摘The results of the assessment of the influence of paper insulation on the discharge initiation in oil were presented in this paper. This assessment based on the results of performed experimental works and on the analysis of electrical field distribution. Both types of the studies were connected with the model HV （high voltage） electrode setups covered by paper and immersed in oil. Experimental works indicated that the source of ＂weak points＂ of paper-oil model electrode setup is oil, not the surface of metal or insulation wrapping. Such hypothesis, resulting mainly from the measured times to initiations of discharges developing from bare and insulated HV electrodes, was verified by the analysis of electrical field distribution performed on the basis of finite element method applied in the COMSOL Multiphysics software. This analysis confirmed preliminary the made hypothesis. Correlation with the most stressed oil volume law was also observed.
基金financially supported by the National Natural Science Foundation of China(51672078 and 21473052)Hunan University State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Independent Research Project(71675004)Hunan Youth Talents(2016RS3025)。
文摘The investigation on the cathode material of potassium ion batteries(PIBs),one of the most promising alternatives to lithium ion batteries,is of great significance.Potassium vanadium fluorophosphate(KVPO4F)with a high working voltage is an appealing cathode candidate for PIBs,while the poor cycling performance and low electronic conductivity dramatically hinder the application.Herein,a plum pudding model inspired three-dimensional amorphous carbon network modified KVPO4F composite(KVPO4F@3DC)is successfully designed in this study to tackle these problems.In the composite,KVPO4F particles are homogeneously wrapped by a layer of amorphous carbon and bridged by crosslinked large area carbon sheets.As the cathode for PIBs,the KVPO4F@3DC composite exhibits a high average operating voltage about 4.10 V with a super-high discharge capacity of 102.96 mAh g^-1 at 20 mA g^-1.An excellent long cycle stability with a capacity retention of 85.4%over 550 cycles at 500 mA g^-1 is achieved.In addition,it maintains 83.6%of its initial capacity at 50 mA g^-1 after 100 cycles at 55℃.The design of KVPO4F@3DC with plum pudding structure provides facilitative electron conductive network and stable electrode/electrode interface for electrode,successfully innovating an ultra-stable and high-performance cathode material for potassium ion batteries.
