A 100Ah@42V lead-acid battery package for electric vehicles are used for study. 1he hybrid pulse test is applied to the battery package to acquire enough data, by which the partnership for a new generation of vehicles...A 100Ah@42V lead-acid battery package for electric vehicles are used for study. 1he hybrid pulse test is applied to the battery package to acquire enough data, by which the partnership for a new generation of vehicles （PNGV） equivalent circuit model parameters are identified by the least square method. Then, the PNGV model is verified under two conditions, i.e., the composite pulse excitation and the constant-current respectively. The corresponding maximum relative errors of output voltage are less than 3 % and 3.5 %. Results show that the present PNGV equivalent circuit model and verification method is effective, which can satisfy requirement of simulation of power system of electric vehicles.展开更多
This system can not only monitor the video signals from 16TV cameras at 10 different spots simultaneously, but also telecontrol the 16 cameras. The hardware in the system is simple, applicable and reliable, because in...This system can not only monitor the video signals from 16TV cameras at 10 different spots simultaneously, but also telecontrol the 16 cameras. The hardware in the system is simple, applicable and reliable, because intelligent components have been adopted and many functions can be achieved by software. Even if the code rates deviate from the designed value (300 baud/s) in 50 times, the remote signals can still be exactly received by the code rate measuring with software. The elash among remote signals from multiple spots is completely eliminated by checking their priorities with software.展开更多
It is necessary to take measures against infectious diseases in the Southeast Asian prawn farming industry. In giant tiger prawn （Penaeus monodon） aquaculture, diseases caused by viruses such as white spot syndrome ...It is necessary to take measures against infectious diseases in the Southeast Asian prawn farming industry. In giant tiger prawn （Penaeus monodon） aquaculture, diseases caused by viruses such as white spot syndrome virus （WSSV） and bacteria such as Vibrio have become a menace. Appropriate treatments of prawn culture pond＇s waters are advocated for preventing and controlling pathogens. The purpose of this study was to conduct an antimicrobial water treatment using a low-voltage pulsed electric field sterilization. Here we prepared a mechanical low-voltage pulsed electric field system with copper wire coiling around a titanium ring. The viability of WSSV in seawater was examined by prawn infectivity experiments. We inoculated healthy prawns （approximately 10-15 g） with the WSSV master sample that passed 0-3 times through the system. WSSV infection in prawns decreased according to the number of passes through the system. Healthy prawns survived for〉 10 days without feeding, where as prawns inoculated with the WSSV master sample showed symptoms of white spot and died in about 4 days. Two-thirds of the prawns inoculated with the WSSV master sample that was passed once through the system developed WSSV symptoms and were polymerase chain reaction （PCR） positive. However, no symptoms were observed and prawns were PCR negative when the WSSV master sample was passed three times through the system. Based on these results, we purpose that a low-voltage pulsed electric field system will serve as an efficient pond drainage sterilization system and will replace conventional treatments using chemicals such as sodium hypochlorite.展开更多
Due to overvoltage produced by inverter output,inverter-fed motor insulation systems often experience fast electrical aging process,especially when partial discharge(PD) is incepted.Before putting into use,the PD dete...Due to overvoltage produced by inverter output,inverter-fed motor insulation systems often experience fast electrical aging process,especially when partial discharge(PD) is incepted.Before putting into use,the PD detection should be performed on inverter-fed motors at repetitive square voltages to avoid the PD caused insulation deterioration when the motors are collected to inverters having specific characteristics.However,unlike PD tests at AC/DC voltages proposed in IEC 60270,the PD detection at repetitive square voltages is much more complex because of serious interference generated by impulse generator.To solve the problem,ultra-high frequency(UHF) method seems recommendable for its preferable signal-to-noise ratio(SNR).The chief aim of this study is to investigate PD pulse and statistical characteristics of turn-to-turn insulation for inverter-fed traction motors.A square-shaped Archimedes antenna,specially designed for the PD detection at repetitive square voltages of fast rise times,was used to perform PD tests on turn-to-turn insulation models.Time and frequency analysis results indicate that energy component of generator disturbance and PD pulses are mainly distributed in the 0-0.5 GHz and 0.6-1.5 GHz range,respectively.Based on the results,suitable filter was designed for power disturbance suppression.Additionally,resorting to the sensor unit(i.e.antenna and filter) and the PD test system,the PD statistical features at square voltages of different frequencies were obtained.Experimental results show that higher frequency will give rise,statistically,to PD of lower magnitudes distributing at smaller phases.A reasonable interpretation of this phenomenon was presented.Lastly,according to the PD statistical features,some suggestions for the PD detection system design,generator parameter optimization and the PD pulse extracting were given.The results of this work would be beneficial to the increase of the sensitivity when performing the PD detection on insulation systems for inverter-fed motors at repetitive square voltages and thus,improving the reliability of inverter-fed motors.展开更多
Schottky-contacted sensors have been demonstrated to show high sensitivity and fast response time in various sensing systems.In order to improve their sensing performance,the Schottky barriers height(SBH)at the interf...Schottky-contacted sensors have been demonstrated to show high sensitivity and fast response time in various sensing systems.In order to improve their sensing performance,the Schottky barriers height(SBH)at the interface of semiconductor and metal electrode should be adjusted to appropriate range to avoid low output or low sensitivity,which was induced by excessively high or low SBH,respectively.In this work,a simple and effective SBH tuning method by triboelectric generator(TENG)is proposed,the SBH can be effectively lowered by voltage pulses generated by TENG and gradually recover over time after withdrawing the TENG.Through combining the TENG treatment with piezotronic effect,a synergistic effect on lowering SBH was achieved.The change of SBH is increased by 3.8 to 12.8 times,compared with dependent TENG treatment and piezotronic effect,respectively.Furthermore,the recovery time of the TENG-lowered SBH can be greatly shortened from 1.5 h to 40 s by piezotronic effect.This work demonstrated a flexible and feasible SBH tuning method,which can be used to effectively improve the sensitivity of Schottky-contact sensor and sensing system.Our study also shows great potential in broadening the application scenarios of Schottky-contacted electronic devices.展开更多
文摘A 100Ah@42V lead-acid battery package for electric vehicles are used for study. 1he hybrid pulse test is applied to the battery package to acquire enough data, by which the partnership for a new generation of vehicles （PNGV） equivalent circuit model parameters are identified by the least square method. Then, the PNGV model is verified under two conditions, i.e., the composite pulse excitation and the constant-current respectively. The corresponding maximum relative errors of output voltage are less than 3 % and 3.5 %. Results show that the present PNGV equivalent circuit model and verification method is effective, which can satisfy requirement of simulation of power system of electric vehicles.
文摘This system can not only monitor the video signals from 16TV cameras at 10 different spots simultaneously, but also telecontrol the 16 cameras. The hardware in the system is simple, applicable and reliable, because intelligent components have been adopted and many functions can be achieved by software. Even if the code rates deviate from the designed value (300 baud/s) in 50 times, the remote signals can still be exactly received by the code rate measuring with software. The elash among remote signals from multiple spots is completely eliminated by checking their priorities with software.
文摘It is necessary to take measures against infectious diseases in the Southeast Asian prawn farming industry. In giant tiger prawn （Penaeus monodon） aquaculture, diseases caused by viruses such as white spot syndrome virus （WSSV） and bacteria such as Vibrio have become a menace. Appropriate treatments of prawn culture pond＇s waters are advocated for preventing and controlling pathogens. The purpose of this study was to conduct an antimicrobial water treatment using a low-voltage pulsed electric field sterilization. Here we prepared a mechanical low-voltage pulsed electric field system with copper wire coiling around a titanium ring. The viability of WSSV in seawater was examined by prawn infectivity experiments. We inoculated healthy prawns （approximately 10-15 g） with the WSSV master sample that passed 0-3 times through the system. WSSV infection in prawns decreased according to the number of passes through the system. Healthy prawns survived for〉 10 days without feeding, where as prawns inoculated with the WSSV master sample showed symptoms of white spot and died in about 4 days. Two-thirds of the prawns inoculated with the WSSV master sample that was passed once through the system developed WSSV symptoms and were polymerase chain reaction （PCR） positive. However, no symptoms were observed and prawns were PCR negative when the WSSV master sample was passed three times through the system. Based on these results, we purpose that a low-voltage pulsed electric field system will serve as an efficient pond drainage sterilization system and will replace conventional treatments using chemicals such as sodium hypochlorite.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51177136,50377035)Zhuzhou Electric Motor Company of South China Locomotive & Rolling Stock Corporation Lim-ited
文摘Due to overvoltage produced by inverter output,inverter-fed motor insulation systems often experience fast electrical aging process,especially when partial discharge(PD) is incepted.Before putting into use,the PD detection should be performed on inverter-fed motors at repetitive square voltages to avoid the PD caused insulation deterioration when the motors are collected to inverters having specific characteristics.However,unlike PD tests at AC/DC voltages proposed in IEC 60270,the PD detection at repetitive square voltages is much more complex because of serious interference generated by impulse generator.To solve the problem,ultra-high frequency(UHF) method seems recommendable for its preferable signal-to-noise ratio(SNR).The chief aim of this study is to investigate PD pulse and statistical characteristics of turn-to-turn insulation for inverter-fed traction motors.A square-shaped Archimedes antenna,specially designed for the PD detection at repetitive square voltages of fast rise times,was used to perform PD tests on turn-to-turn insulation models.Time and frequency analysis results indicate that energy component of generator disturbance and PD pulses are mainly distributed in the 0-0.5 GHz and 0.6-1.5 GHz range,respectively.Based on the results,suitable filter was designed for power disturbance suppression.Additionally,resorting to the sensor unit(i.e.antenna and filter) and the PD test system,the PD statistical features at square voltages of different frequencies were obtained.Experimental results show that higher frequency will give rise,statistically,to PD of lower magnitudes distributing at smaller phases.A reasonable interpretation of this phenomenon was presented.Lastly,according to the PD statistical features,some suggestions for the PD detection system design,generator parameter optimization and the PD pulse extracting were given.The results of this work would be beneficial to the increase of the sensitivity when performing the PD detection on insulation systems for inverter-fed motors at repetitive square voltages and thus,improving the reliability of inverter-fed motors.
基金the National Key R&D Program of China(2016YFA0202703)Key-Area Research and Development Program of Guangdong Province(2018B030331001)+3 种基金the National Natural Science Foundation of China(61875015,81971770,52002027,and 82071970)Beijing Natural Science Foundation(JQ20038,2214083)China National Postdoctoral Program for Innovative Talent(BX20200380)the Fundamental Research Funds for the Central Universities。
文摘Schottky-contacted sensors have been demonstrated to show high sensitivity and fast response time in various sensing systems.In order to improve their sensing performance,the Schottky barriers height(SBH)at the interface of semiconductor and metal electrode should be adjusted to appropriate range to avoid low output or low sensitivity,which was induced by excessively high or low SBH,respectively.In this work,a simple and effective SBH tuning method by triboelectric generator(TENG)is proposed,the SBH can be effectively lowered by voltage pulses generated by TENG and gradually recover over time after withdrawing the TENG.Through combining the TENG treatment with piezotronic effect,a synergistic effect on lowering SBH was achieved.The change of SBH is increased by 3.8 to 12.8 times,compared with dependent TENG treatment and piezotronic effect,respectively.Furthermore,the recovery time of the TENG-lowered SBH can be greatly shortened from 1.5 h to 40 s by piezotronic effect.This work demonstrated a flexible and feasible SBH tuning method,which can be used to effectively improve the sensitivity of Schottky-contact sensor and sensing system.Our study also shows great potential in broadening the application scenarios of Schottky-contacted electronic devices.
