On the basis of detailed analysis of a novel harmonic counteracting method which can be used to effectively compensate the supply line harmonic currents of a passive single phase diode bridge rectifier, this paper pr...On the basis of detailed analysis of a novel harmonic counteracting method which can be used to effectively compensate the supply line harmonic currents of a passive single phase diode bridge rectifier, this paper presents two simpler single phase diode bridge rectifier configurations and their alternatives which can achieve low supply line current THD(total harmonic distortion) too. Moreover, this paper also proposes a few passive hamonic counteracting networks for multi single phase rectifiers which are connected in parallel.展开更多
A high-accuracy,low-dropout （LDO） voltage regulator is presented. Using the slow-rolloff frequency compensation scheme, the LDO effectively overcomes the stability problem, facilitates the use of a ceramic capacitor...A high-accuracy,low-dropout （LDO） voltage regulator is presented. Using the slow-rolloff frequency compensation scheme, the LDO effectively overcomes the stability problem, facilitates the use of a ceramic capacitor, and improves the output voltage accuracy, which is critical for powering high-performance analog circuitry. The slow-rolloff compensation scheme is realized by introducing three pole-zero pairs, including the proposed polezero pair and sense zero. The post-layout simulation results demonstrate that this LDO has robust system stability, a high open-loop gain, and a high unit-gain frequency,which lead to excellent regulation and transient response performance. The line and load regulation are 27μV/V and 3.78μV/mA, and the overshoots of the output voltage are less than 30mV,while the dropout voltage is 120mV for a 150mA load current.展开更多
To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current i...To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current inverter to generate compensating currents and injecting the currents directly into the DC side of the system,the grid-side currents of the rectifier can be approximated to sine wave.Using zigzag autotransformer as phase-shifting transformer can block the zero sequence current components and reduce the equivalent capacity of the rectifying system.The study on harmonic distortion rate of grid-side currents with the variation of the load shows that the harmonic content of the compensated rectifier decreases significantly under various load conditions.The harmonic content of the grid-side currents of the proposed active injection rectifier is only 1.17%,and the equivalent capacity of the rectifier is calculated.The results show that the rectifier can not only suppress the harmonic currents,but also have a lower equivalent capacity.展开更多
Objective：To establish the polytransgenic mice expressing the human HT and complement regulatory proteins （CRPs） and discuss their ability to resist the hyperacute rejection （HAR） and delayed xenograft rejection ...Objective：To establish the polytransgenic mice expressing the human HT and complement regulatory proteins （CRPs） and discuss their ability to resist the hyperacute rejection （HAR） and delayed xenograft rejection （DXR） of heterogenic transplantation. Methods ：Transgenic mice were produced by microinjection to construct gene for human HT, delay acceleration factor （DAF） and/or CD59 into the male pronucleus of zygote. PCR and Southern blot were used to screen the positive trarisgenic mice. Flow cytometry （FCM） was used to detect the expression of HT, ct-Gal and DAF or CD59 on the PBMCs of transgenic mice. The survival time and function of the heart of transgenic mice were determined by a modified Langendorff cardiac perfusion apparatus： The change of proteinosis on IgM,IgG, C3c and C9 from different cardiac vascular iendothelial cells of transgenic mice were detected by immunohistochemistry. Results：HT, DAF or CD59 were highly expressed on the positive transgenic mice by FCM. The deposition of IgM,IgG,C3c or C9 in the cardiac vascular endothelial cells of the positive transgenic mice were de- creased. The survival time and function of the heart of the co-transgenic mice with AB serum perfusion were significantly longer and higher than that of the single HT positive transgenic mice（P 〈0.05）. Conclusion ：The mice co-expressing HT/DAF or HT/CD59 could resist the HAR,which was better than those expressing HT alone. It is feasible to use HT and CRPs co-transgenic methods to resist the HAR and DXR.展开更多
This paper introduces a launch vehicle scheme for the new generation of cryogenic and quick-launch launch vehicle(LM-6). The main technical innovations of LM-6 launch vehicle include the capability of twenty satellite...This paper introduces a launch vehicle scheme for the new generation of cryogenic and quick-launch launch vehicle(LM-6). The main technical innovations of LM-6 launch vehicle include the capability of twenty satellites launched by one vehicle, high-pressure staged combustion cycle engine and oxygen tank self-pressurization, sandwich bulkhead tank with 200 K temperature difference, and 7-day quick-launch using the "three horizontals" test and launch mode with integral transportation and erection. The future development of the quick-launch launch vehicle is predicted based upon the need for vehicle mission coverage improvement, better response speed, and stronger market competiveness.展开更多
For low power dielectric barrier discharge （DBD） used in small-size material treatment or portable devices, high- step transformer parasitic capacitance greatly influences the performance of the resonant converter a...For low power dielectric barrier discharge （DBD） used in small-size material treatment or portable devices, high- step transformer parasitic capacitance greatly influences the performance of the resonant converter as it is of the same order of magnitude as the equivalent capacitance of DBD load. In this paper, steady-state analysis of the low power DBD is presented, considering the inevitable parasitic capacitance of the high-step transformer. The rectifier-compensated first harmonic approxi- mation （RCFHA） is applied to linearize the equivalent load circuit of DBD at low frequency and the derived expressions are accurate and convenient for the analysis and design of the power supply. Based on the proposed linear equivalent load circuit, the influence of transformer parasitic capacitance on the key parameters, including the frequency range and the applied electrode voltage, is discussed when the power is regulated with pulse frequency modulation （PFM）. Also, a design procedure is presented based on the derived expressions. A prototype is constructed according to the design results and the accuracy of the design is verified by experimental results.展开更多
Selenocosmia huwena and Selenocosmia hainana are two tarantula species found in southern China.Their venoms contain abundant peptide toxins.Two new neurotoxic peptides,huwentoxin-Ⅲ(HWTX-Ⅲ) and hainantoxin-VI(HNTX-VI...Selenocosmia huwena and Selenocosmia hainana are two tarantula species found in southern China.Their venoms contain abundant peptide toxins.Two new neurotoxic peptides,huwentoxin-Ⅲ(HWTX-Ⅲ) and hainantoxin-VI(HNTX-VI),were obtained from the venom using ion-exchange chromatography and reverse-phase high performance liquid chromatography(RP-HPLC).The mechanism of action of HWTX-Ⅲ and HNTX-VI on insect neuronal voltage-gated sodium channels(VGSCs) was studied via whole-cell patch clamp techniques.In a fashion similar to δ-atracotoxins,HNTX-VI can induce a slowdown of current inactivation of the VGSC and reduction in the peak of Na+ current in cockroach dorsal unpaired median(DUM) neurons.Meanwhile,10 μmol/L HNTX-IV caused a positive shift of steady-state inactivation of sodium channel.HWTX-ⅡI inhibited VGSCs on DUM neurons(concentration of toxin at half-maximal inhibition(IC50)≈1.106 μmol/L) in a way much similar to tetrodotoxin(TTX).HWTX-Ⅲ had no effect on the kinetics of activation and inactivation.The shift in the steady-state inactivation curve was distinct from other depressant spider toxins.The diverse effect and the mechanism of action of the two insect toxins illustrate the diverse biological activities of spider toxins and provide a fresh theoretical foundation to design and develop novel insecticides.展开更多
文摘On the basis of detailed analysis of a novel harmonic counteracting method which can be used to effectively compensate the supply line harmonic currents of a passive single phase diode bridge rectifier, this paper presents two simpler single phase diode bridge rectifier configurations and their alternatives which can achieve low supply line current THD(total harmonic distortion) too. Moreover, this paper also proposes a few passive hamonic counteracting networks for multi single phase rectifiers which are connected in parallel.
文摘A high-accuracy,low-dropout （LDO） voltage regulator is presented. Using the slow-rolloff frequency compensation scheme, the LDO effectively overcomes the stability problem, facilitates the use of a ceramic capacitor, and improves the output voltage accuracy, which is critical for powering high-performance analog circuitry. The slow-rolloff compensation scheme is realized by introducing three pole-zero pairs, including the proposed polezero pair and sense zero. The post-layout simulation results demonstrate that this LDO has robust system stability, a high open-loop gain, and a high unit-gain frequency,which lead to excellent regulation and transient response performance. The line and load regulation are 27μV/V and 3.78μV/mA, and the overshoots of the output voltage are less than 30mV,while the dropout voltage is 120mV for a 150mA load current.
基金National Natural Science Foundation of China(No.51767013)Science and Technology Research and Development Plan of China Railway Corporation(No.2017J012-A)Lanzhou City Science and Technology Program for Innovation and Entrepreneurship of Talents(No.2017-RC-51)。
文摘To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current inverter to generate compensating currents and injecting the currents directly into the DC side of the system,the grid-side currents of the rectifier can be approximated to sine wave.Using zigzag autotransformer as phase-shifting transformer can block the zero sequence current components and reduce the equivalent capacity of the rectifying system.The study on harmonic distortion rate of grid-side currents with the variation of the load shows that the harmonic content of the compensated rectifier decreases significantly under various load conditions.The harmonic content of the grid-side currents of the proposed active injection rectifier is only 1.17%,and the equivalent capacity of the rectifier is calculated.The results show that the rectifier can not only suppress the harmonic currents,but also have a lower equivalent capacity.
基金Tianjin Municipal Science and Technology CommissionGrant number:043803411
文摘Objective：To establish the polytransgenic mice expressing the human HT and complement regulatory proteins （CRPs） and discuss their ability to resist the hyperacute rejection （HAR） and delayed xenograft rejection （DXR） of heterogenic transplantation. Methods ：Transgenic mice were produced by microinjection to construct gene for human HT, delay acceleration factor （DAF） and/or CD59 into the male pronucleus of zygote. PCR and Southern blot were used to screen the positive trarisgenic mice. Flow cytometry （FCM） was used to detect the expression of HT, ct-Gal and DAF or CD59 on the PBMCs of transgenic mice. The survival time and function of the heart of transgenic mice were determined by a modified Langendorff cardiac perfusion apparatus： The change of proteinosis on IgM,IgG, C3c and C9 from different cardiac vascular iendothelial cells of transgenic mice were detected by immunohistochemistry. Results：HT, DAF or CD59 were highly expressed on the positive transgenic mice by FCM. The deposition of IgM,IgG,C3c or C9 in the cardiac vascular endothelial cells of the positive transgenic mice were de- creased. The survival time and function of the heart of the co-transgenic mice with AB serum perfusion were significantly longer and higher than that of the single HT positive transgenic mice（P 〈0.05）. Conclusion ：The mice co-expressing HT/DAF or HT/CD59 could resist the HAR,which was better than those expressing HT alone. It is feasible to use HT and CRPs co-transgenic methods to resist the HAR and DXR.
文摘This paper introduces a launch vehicle scheme for the new generation of cryogenic and quick-launch launch vehicle(LM-6). The main technical innovations of LM-6 launch vehicle include the capability of twenty satellites launched by one vehicle, high-pressure staged combustion cycle engine and oxygen tank self-pressurization, sandwich bulkhead tank with 200 K temperature difference, and 7-day quick-launch using the "three horizontals" test and launch mode with integral transportation and erection. The future development of the quick-launch launch vehicle is predicted based upon the need for vehicle mission coverage improvement, better response speed, and stronger market competiveness.
基金supported by the National Natural Science Foundation of China(No.51107115)the China Postdoctoral Science Foundation(No.20110491766)
文摘For low power dielectric barrier discharge （DBD） used in small-size material treatment or portable devices, high- step transformer parasitic capacitance greatly influences the performance of the resonant converter as it is of the same order of magnitude as the equivalent capacitance of DBD load. In this paper, steady-state analysis of the low power DBD is presented, considering the inevitable parasitic capacitance of the high-step transformer. The rectifier-compensated first harmonic approxi- mation （RCFHA） is applied to linearize the equivalent load circuit of DBD at low frequency and the derived expressions are accurate and convenient for the analysis and design of the power supply. Based on the proposed linear equivalent load circuit, the influence of transformer parasitic capacitance on the key parameters, including the frequency range and the applied electrode voltage, is discussed when the power is regulated with pulse frequency modulation （PFM）. Also, a design procedure is presented based on the derived expressions. A prototype is constructed according to the design results and the accuracy of the design is verified by experimental results.
基金supported by the National Natural Science Foundation of China (No.30500146)the National Basic Research Program (973) of China (No.2006CB708508)
文摘Selenocosmia huwena and Selenocosmia hainana are two tarantula species found in southern China.Their venoms contain abundant peptide toxins.Two new neurotoxic peptides,huwentoxin-Ⅲ(HWTX-Ⅲ) and hainantoxin-VI(HNTX-VI),were obtained from the venom using ion-exchange chromatography and reverse-phase high performance liquid chromatography(RP-HPLC).The mechanism of action of HWTX-Ⅲ and HNTX-VI on insect neuronal voltage-gated sodium channels(VGSCs) was studied via whole-cell patch clamp techniques.In a fashion similar to δ-atracotoxins,HNTX-VI can induce a slowdown of current inactivation of the VGSC and reduction in the peak of Na+ current in cockroach dorsal unpaired median(DUM) neurons.Meanwhile,10 μmol/L HNTX-IV caused a positive shift of steady-state inactivation of sodium channel.HWTX-ⅡI inhibited VGSCs on DUM neurons(concentration of toxin at half-maximal inhibition(IC50)≈1.106 μmol/L) in a way much similar to tetrodotoxin(TTX).HWTX-Ⅲ had no effect on the kinetics of activation and inactivation.The shift in the steady-state inactivation curve was distinct from other depressant spider toxins.The diverse effect and the mechanism of action of the two insect toxins illustrate the diverse biological activities of spider toxins and provide a fresh theoretical foundation to design and develop novel insecticides.
