A novel SiC double-trench metal-oxide-semiconductor field effect transistor(MOSFET) with integrated MOS-channel diode is proposed and investigated by Sentaurus TCAD simulation. The new SiC MOSFET has a trench gate and...A novel SiC double-trench metal-oxide-semiconductor field effect transistor(MOSFET) with integrated MOS-channel diode is proposed and investigated by Sentaurus TCAD simulation. The new SiC MOSFET has a trench gate and a stepped-trench source, and features an integrated MOS-channel diode on the top sidewall of the source trench(MT MOS). In the reverse conduction state, the MOS-channel diode turns on firstly to prevent the internal parasitic body diode being activated, and thus reduces the turn-on voltage VFand suppresses the bipolar degradation phenomena. The VFof1.70 V(@Ids=-100 A/cm^(2)) for the SiC MT MOS is 38.2% lower than that of SiC double-trench MOSFET(DT MOS).Meanwhile, the reverse recovery charge Qrrof the MT MOS is 58.7% lower than that of the DT MOS at Iload= 700 A/cm^(2),and thus the reverse recovery loss is reduced. Furthermore, owing to the modulation effect induced by the double trenches,the MT MOS preserves the same superior forward conduction and blocking performance as those of DT MOS, with 22.9% and 18.2% improvement on breakdown voltage and RON,spcompared to the trench gate MOSFET with planar integrated SBD(ST MOS).展开更多
The aim of this study was to investigate proton magnetic resonance spectroscopy metabolite values in the medial prefrontal cortex of individuals with euthymic bipolar disorder. The subjects consisted of 15 patients wi...The aim of this study was to investigate proton magnetic resonance spectroscopy metabolite values in the medial prefrontal cortex of individuals with euthymic bipolar disorder. The subjects consisted of 15 patients with euthymic bipolar disorder type I and 15 healthy controls. We performed proton magnetic resonance spectroscopy of the bilateral medial prefrontal cortex and measured levels of N-acetyl aspartate, choline and creatine. Levels of these three metabolites in the medial prefrontal cortex were found to be lower in patients with bipolar disorder compared with healthy controls. A positive correlation was found between illness duration and choline levels in the right medial prefrontal cortex. Our study suggests that during the euthymic period, there are abnormalities in cellular energy and membrane phospholipid metabolism in the medial prefrontal cortex, and that this may impair neuronal activity and integrity.展开更多
SiC MOSFET体二极管双极退化是由材料缺陷导致的退化现象,严重影响器件的可靠性,目前没有统一的试验方法,影响了器件的推广和应用。从加电模式、加电条件、试验时间和失效判据4个方面对体二极管双极退化可靠性试验方法进行了研究,并编...SiC MOSFET体二极管双极退化是由材料缺陷导致的退化现象,严重影响器件的可靠性,目前没有统一的试验方法,影响了器件的推广和应用。从加电模式、加电条件、试验时间和失效判据4个方面对体二极管双极退化可靠性试验方法进行了研究,并编制了体二极管双极退化可靠性试验方法草案。展开更多
为进一步提高介质阻挡放电(DBD)降解甲醛的效率,并控制副产物的生成量,采用正负双极性高压脉冲电源对同轴式介质阻挡反应器供电,系统地研究了脉冲电压、脉冲重复频率、放电间隙、气体体积流量及甲醛初始质量浓度等影响因素对甲醛降解率...为进一步提高介质阻挡放电(DBD)降解甲醛的效率,并控制副产物的生成量,采用正负双极性高压脉冲电源对同轴式介质阻挡反应器供电,系统地研究了脉冲电压、脉冲重复频率、放电间隙、气体体积流量及甲醛初始质量浓度等影响因素对甲醛降解率及臭氧生成质量浓度的影响。实验结果表明:升高脉冲电压有利于甲醛的降解,当脉冲电压达到19 k V时,脉冲电压继续升高对甲醛降解率的影响不大,而臭氧生成质量浓度随着脉冲电压的增加而不断增大;放电间隙对甲醛降解率有很大的影响,随着放电间隙的减小,甲醛降解率增大,但放电间隙过小时,臭氧生成质量浓度较大;随着气体体积流量的增大,甲醛降解率降低;随着脉冲重复频率的增大,甲醛降解率增大,当脉冲重复频率达到60 Hz时,继续增加脉冲重复频率,甲醛降解率增大不明显;在一定实验条件下,甲醛初始质量浓度越大,甲醛降解率降低,而甲醛去除质量浓度增大并趋近于反应器的最大处理量。展开更多
Ionizing-radiation-induced current gain degradation in NPN bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A model is presented which ident...Ionizing-radiation-induced current gain degradation in NPN bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A model is presented which identifies the physical mechanism responsible for current gain degradation. The increase in surface recombination velocity due to interface states results in an increase in base current. Besides, changing the surface potential along the base surface induced by the oxide-trapped charges can also lead to an increased base current. By combining the production mechanisms of oxide-trapped charges and interface states, this model can explain the fact that the current gain degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 70 krad（Si）. The low dose rate was 0.1 rad（Si）/s and the high dose rate was 10 rad（Si）/s. The model accords well with the experimental results.展开更多
Radiation-induced 1/f noise degradation in the LM117 bipolar linear voltage regulator is studied. Based on the radiation-induced degradation mechanism of the output voltage, it is suggested that the band-gap reference...Radiation-induced 1/f noise degradation in the LM117 bipolar linear voltage regulator is studied. Based on the radiation-induced degradation mechanism of the output voltage, it is suggested that the band-gap reference subcircuit is the critical component which leads to the 1/f noise degradation of the LM117. The radiation makes the base surface current of the bipolar junction transistors of the band-gap reference subcircuit increase, which leads to an increase in the output 1/f noise of the LM117. Compared to the output voltage, the 1/f noise parameter is more sensitive, it may be used to evaluate the radiation resistance capability of LM117.展开更多
基金the support by the Science & Technology Program (High voltage and high power SiC material, devices and the application demonstration in power electronic transformers) of the State Grid Corporation of China Co. Ltd.supported by the National Key Research and Development Program of China (Grant No. 2016YFB0400502)。
文摘A novel SiC double-trench metal-oxide-semiconductor field effect transistor(MOSFET) with integrated MOS-channel diode is proposed and investigated by Sentaurus TCAD simulation. The new SiC MOSFET has a trench gate and a stepped-trench source, and features an integrated MOS-channel diode on the top sidewall of the source trench(MT MOS). In the reverse conduction state, the MOS-channel diode turns on firstly to prevent the internal parasitic body diode being activated, and thus reduces the turn-on voltage VFand suppresses the bipolar degradation phenomena. The VFof1.70 V(@Ids=-100 A/cm^(2)) for the SiC MT MOS is 38.2% lower than that of SiC double-trench MOSFET(DT MOS).Meanwhile, the reverse recovery charge Qrrof the MT MOS is 58.7% lower than that of the DT MOS at Iload= 700 A/cm^(2),and thus the reverse recovery loss is reduced. Furthermore, owing to the modulation effect induced by the double trenches,the MT MOS preserves the same superior forward conduction and blocking performance as those of DT MOS, with 22.9% and 18.2% improvement on breakdown voltage and RON,spcompared to the trench gate MOSFET with planar integrated SBD(ST MOS).
基金supported by Pamukkale University(Scientific Research Projects Coordination Unit)
文摘The aim of this study was to investigate proton magnetic resonance spectroscopy metabolite values in the medial prefrontal cortex of individuals with euthymic bipolar disorder. The subjects consisted of 15 patients with euthymic bipolar disorder type I and 15 healthy controls. We performed proton magnetic resonance spectroscopy of the bilateral medial prefrontal cortex and measured levels of N-acetyl aspartate, choline and creatine. Levels of these three metabolites in the medial prefrontal cortex were found to be lower in patients with bipolar disorder compared with healthy controls. A positive correlation was found between illness duration and choline levels in the right medial prefrontal cortex. Our study suggests that during the euthymic period, there are abnormalities in cellular energy and membrane phospholipid metabolism in the medial prefrontal cortex, and that this may impair neuronal activity and integrity.
文摘为进一步提高介质阻挡放电(DBD)降解甲醛的效率,并控制副产物的生成量,采用正负双极性高压脉冲电源对同轴式介质阻挡反应器供电,系统地研究了脉冲电压、脉冲重复频率、放电间隙、气体体积流量及甲醛初始质量浓度等影响因素对甲醛降解率及臭氧生成质量浓度的影响。实验结果表明:升高脉冲电压有利于甲醛的降解,当脉冲电压达到19 k V时,脉冲电压继续升高对甲醛降解率的影响不大,而臭氧生成质量浓度随着脉冲电压的增加而不断增大;放电间隙对甲醛降解率有很大的影响,随着放电间隙的减小,甲醛降解率增大,但放电间隙过小时,臭氧生成质量浓度较大;随着气体体积流量的增大,甲醛降解率降低;随着脉冲重复频率的增大,甲醛降解率增大,当脉冲重复频率达到60 Hz时,继续增加脉冲重复频率,甲醛降解率增大不明显;在一定实验条件下,甲醛初始质量浓度越大,甲醛降解率降低,而甲醛去除质量浓度增大并趋近于反应器的最大处理量。
基金Project supported by the National Natural Science Foundation of China(Nos.61076101,61204092)
文摘Ionizing-radiation-induced current gain degradation in NPN bipolar junction transistors is due to an increase in base current as a result of recombination at the surface of the device. A model is presented which identifies the physical mechanism responsible for current gain degradation. The increase in surface recombination velocity due to interface states results in an increase in base current. Besides, changing the surface potential along the base surface induced by the oxide-trapped charges can also lead to an increased base current. By combining the production mechanisms of oxide-trapped charges and interface states, this model can explain the fact that the current gain degradation is more severe at a low dose rate than at a high dose rate. The radiations were performed in a Co60 source up to a total dose of 70 krad（Si）. The low dose rate was 0.1 rad（Si）/s and the high dose rate was 10 rad（Si）/s. The model accords well with the experimental results.
基金Project supported by the National Natural Science Foundation of China(Nos.61076101,61204092)
文摘Radiation-induced 1/f noise degradation in the LM117 bipolar linear voltage regulator is studied. Based on the radiation-induced degradation mechanism of the output voltage, it is suggested that the band-gap reference subcircuit is the critical component which leads to the 1/f noise degradation of the LM117. The radiation makes the base surface current of the bipolar junction transistors of the band-gap reference subcircuit increase, which leads to an increase in the output 1/f noise of the LM117. Compared to the output voltage, the 1/f noise parameter is more sensitive, it may be used to evaluate the radiation resistance capability of LM117.
