The transmural heterogeneous changes of transient outward potassium currents (Ito) in rabbit hypertrophic cardiaomyocytes and the effects of long-term prophylactic treatment with volsartan were investigated. Rabbits w...The transmural heterogeneous changes of transient outward potassium currents (Ito) in rabbit hypertrophic cardiaomyocytes and the effects of long-term prophylactic treatment with volsartan were investigated. Rabbits were divided into hypertrophy group (left ventricular hypertrophy induced by partial ligation of abdominal aorta), vol-treated group (volsartan was administrated after the ligation), and control group (sham operated). Myocytes were isolated by a two-step enzymatical method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from midmyocardium (Mid) with a razor. Whole-cell patch-clamp technique was used to record potassium currents. The results showed that membrane capacitance was larger in hypertrophic cells than those in control and vol-treated cells (P<0.01 vs control cells, n=30). The densities of Ito in hypertrophic cells were reduced by sub-epicardium (Epi) (27.8±2.9) %, midmyocardium (Mid) (41.0±4.7) %, and sub-endocardium (Endo) (20.3±3.4) % compared with those in control cells. The decrease of Ito density was more pronounced in Mid than in Epi and Endo (P<0.01 vs Epi or Endo). There were no significant differences in Ito densities between vol-treated group and control group in three layers separately. In conclusion, volsartan can inhibit the transmural heterogeneous changes of Ito in left ventricular hypertrophic cardiomyocytes in rabbit.展开更多
To address the problem of floating and aggregation of Ag-GNSs in the molten pool during the traditional reflow soldering process,Cu/SAC/Ag-GNSs/Cu sandwich joints were prepared under an applied current density(1.0...To address the problem of floating and aggregation of Ag-GNSs in the molten pool during the traditional reflow soldering process,Cu/SAC/Ag-GNSs/Cu sandwich joints were prepared under an applied current density(1.0×10^(4) A/cm^(2))for a few hundred milliseconds to produce Ag-coated graphene-reinforced Sn-Ag-Cu(SAC/AgGNSs)solder joints.The experimental results showed that Ag-GNSs were homogenously dispersed in the solder joints,providing more Cu6 Sn5 grain nucleation sites,which refined these grains and reduced the thickness difference at the anode and cathode.In addition,the Cu6 Sn5 morphology changed from rod-like to plate-shaped because of the uniform distribution of Ag-GNSs and constitutional supercooling.The significantly increased shear strength of the transient current bonding and the change in the fracture mechanism were due to the uniformly distributed Ag-GNSs and the microstructural changes.展开更多
The electromagnetic concentrative coils are indispensable in the functional magnetic stimulation and have potential applications in nondestructive testing. In this paper, we propose a figure-8-shaped coil being compos...The electromagnetic concentrative coils are indispensable in the functional magnetic stimulation and have potential applications in nondestructive testing. In this paper, we propose a figure-8-shaped coil being composed of two arbitrary oblique elliptical coils, which can change the electromagnetic concentrative region and the magnitude of eddy current density by changing the elliptical shape and/or spread angle between two elliptical coils. Pulsed current is usually the excitation source in the functional magnetic stimulation, so in this paper we derive the analytical solutions of transient pulsed eddy current field in the time domain due to the elliptical concentrative coil placed in an arbitrary position over a half-infinite plane conductor by making use of the scale-transformation, the Laplace transform and the Fourier transform are used in our derivation. Calculation results of field distributions produced by the figure-8-shaped elliptical coil show some behaviours as follows： 1） the eddy currents are focused on the conductor under the geometric symmetric centre of figure-8-shaped coil; 2） the greater the scale factor of ellipse is, the higher the eddy current density is and the wider the concentrative area of eddy current along y axis is; 3） the maximum magnitude of eddy current density increases with the increase of spread angle. When spread angle is 180°, there are two additional reverse concentrative areas on both sides of x axis.展开更多
Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The e...Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The experiment revealed that the amplitude of transient outward potassium channel current was reduced.The maximum activated current densities of control group and exposure group were 163.62±20.68 pA/pF and 98.74±16.57 pA/pF(n=12,P<0.01) respectively.The static magnetic field exposure affected the activation and inactivation process of transient outward potassium channel current.Due to the magnetic field exposure,the half-activation voltage of the activation curves changed from 5.59±1.96 mV to 27.87±7.24 mV(n=12,P<0.05) ,and the slope factor changed from 19.43±2.11 mV to 25.87±4.22 mV(n=12,P<0.05) .The half-inactivation voltage of the inactivation curves also changed from-56.09±0.89 mV to-57.16±1.10 mV(n=12,P>0.05) and the slope factor of the inactivation curves from 8.69±0.80 mV to 10.87±1.02 mV(n=12,P<0.05) .The results show that the static magnetic field can change the characteristics of transient outward K+ channel,and affect the physiological functions of neurons.展开更多
Silicon-germanium （SiGe） hereto-junction bipolar transistor current transients induced by pulse laser and heavy iron are measured using a real-time digital oscilloscope. These transients induced by pulse laser and h...Silicon-germanium （SiGe） hereto-junction bipolar transistor current transients induced by pulse laser and heavy iron are measured using a real-time digital oscilloscope. These transients induced by pulse laser and heavy iron exhibit the same waveform and charge collection time except for the amplitude of peak current. Different laser energies and voltage biases under heavy ion irradiation also have impact on current transient, whereas the waveform remains unchanged. The position-correlated current transients suggest that the nature of the current transient is controlled by the behavior of the C/S junction.展开更多
The transient current behaviour for Iron in 3.5%NaCl and 3.5%NaCl +1%NaNO2 solutions during corrosion fatigue (CF) process has been investigated at different given strain amplitudes and strain rates. The results show ...The transient current behaviour for Iron in 3.5%NaCl and 3.5%NaCl +1%NaNO2 solutions during corrosion fatigue (CF) process has been investigated at different given strain amplitudes and strain rates. The results show that elastic strain has little contribution to material dissolution. The elastic tension strain results in the decrease in the transient current, while the elastic compression strain increases the transient current. Compared to the elastic deformation, plastic deformation affects material dissolution evidently For iron in 3.5%NaCl solution, the strain amplitude plays a dominant role in the dissolution process accelerated by the plastic strain, while in 3.5%NaCl+1%NaNO2 solution, both the strain amplitude and strain rate play an important role in this process. In this paper, the effect of the elastic deformation on the material dissolution and the relation between the tension and compression current peak values under the plastic cycle deformation are discussed展开更多
A novel transient rotor current control scheme is proposed in this paper for a doubly-fed induction generator（DFIG）equipped with a superconducting magnetic energy storage（SMES） device to enhance its transient volt...A novel transient rotor current control scheme is proposed in this paper for a doubly-fed induction generator（DFIG）equipped with a superconducting magnetic energy storage（SMES） device to enhance its transient voltage and frequency support capacity during grid faults. The SMES connected to the DC-link capacitor of the DFIG is controlled to regulate the transient dc-link voltage so that the whole capacity of the grid side converter（GSC） is dedicated to injecting reactive power to the grid for the transient voltage support. However, the rotor-side converter（RSC） has different control tasks for different periods of the grid fault. Firstly, for Period I, the RSC injects the demagnetizing current to ensure the controllability of the rotor voltage. Then, since the dc stator flux degenerates rapidly in Period II, the required demagnetizing current is low in Period II and the RSC uses the spare capacity to additionally generate the reactive（priority） and active current so that the transient voltage capability is corroborated and the DFIG also positively responds to the system frequency dynamic at the earliest time. Finally, a small amount of demagnetizing current is provided after the fault clearance. Most of the RSC capacity is used to inject the active current to further support the frequency recovery of the system. Simulations are carried out on a simple power system with a wind farm. Comparisons with other commonly used control methods are performed to validate the proposed control method.展开更多
The single event transient(SET)effect in nanotube tunneling field-effect transistor with bias-induced electron–hole bilayer(EHBNT-TFET)is investigated by 3-D TCAD simulation for the first time.The effects of linear e...The single event transient(SET)effect in nanotube tunneling field-effect transistor with bias-induced electron–hole bilayer(EHBNT-TFET)is investigated by 3-D TCAD simulation for the first time.The effects of linear energy transfer(LET),characteristic radius,strike angle,electrode bias and hit location on SET response are evaluated in detail.The simulation results show that the peak value of transient drain current is up to 0.08 m A for heavy ion irradiation with characteristic radius of 50 nm and LET of 10 Me V·cm^(2)/mg,which is much higher than the on-state current of EHBNTTFET.The SET response of EHBNT-TFET presents an obvious dependence on LET,strike angle,drain bias and hit location.As LET increases from 2 Me V·cm^(2)/mg to 10 Me V·cm^(2)/mg,the peak drain current increases monotonically from 0.015 mA to 0.08 mA.The strike angle has an greater impact on peak drain current especially for the smaller characteristic radius.The peak drain current and collected charge increase by 0.014 mA and 0.06 fC,respectively,as the drain bias increases from 0.1 V to 0.9 V.Whether from the horizontal or the vertical direction,the most sensitive hit location is related to wt.The underlying physical mechanism is explored and discussed.展开更多
To determine the effects of HOE 694, a new and potent Na＋- H＋ exchanger blocker, on transient inward current (Iti) and Na＋- Ca2＋ exchange during hypoxia- reoxygenation in guinea pig cardiomyocytes. Methods. Cardio...To determine the effects of HOE 694, a new and potent Na＋- H＋ exchanger blocker, on transient inward current (Iti) and Na＋- Ca2＋ exchange during hypoxia- reoxygenation in guinea pig cardiomyocytes. Methods. Cardiomyocytes were isolated from adult guinea pig ventricle. Experiment was performed in an experimental chamber that allowed the cells to be exposed to a sufficiently low O2 pressure. The cells were subjected to hypoxia and reoxygenation. The ionic currents were studied with patch clamp technique. Results. In the absence of HOE 694, hypoxia- reoxygenation induced Iti in 12 of 15 experiments; but in cardiomyocytes pretreated with HOE 694 (10～ 50μ mol/L), the incidence of Iti observed during reoxygenation was reduced to 5 of 11 experiments and 3 of 10 experiments, P Conclusions. Blockade of the Na＋- H＋ exchange by HOE 694 could reduce Ca2＋ overload upon hypoxia- reoxygenation, and inhibition of Na＋- H＋ exchange may also indirectly decrease Na＋- Ca2＋ exchange activity during hypoxia.展开更多
Objective ：To investigate the different suppressive effect of lidocaine on persistent Na^＋ current and transient Na^＋ current in injured or uninjured dorsal root ganglion neurons. Methods： Totally 23 SD rats were ...Objective ：To investigate the different suppressive effect of lidocaine on persistent Na^＋ current and transient Na^＋ current in injured or uninjured dorsal root ganglion neurons. Methods： Totally 23 SD rats were randomly divided into 2 groups： control group （n： 10） and chronically compressed DRG （dorsal root ganglion） group （CCD group, n= 13）. Rats were anesthetized and DRG was isolated. Single DRG neuron was isolated by enzymatic disassociation method. Persistent Na^＋ current （INap） and transient Na^＋ current （INaT） were elicited in voltage clamp mode. Results： The presence of INap was testified in most DRG neurons （38/46 neurons in CCD group and 31/39 neurons in control group, P〉0. 05）. However, the cur- rent density of INap in CCD group （4. 6±0. 6 pA/pF, n=38 neurons） was greater than that in control group （2.5±0.4 pA/pF, n=31 neurons） （P〈0. 05）. The characteristics of INap was observed and found that INap could he blocked by 0.2 μmol/L tetrodotoxin easily. Furthermore, the does-effect relationship of lidocaine on INaP and IN.T were also examined. INaP and IN.T were suppressed by different concentrations of li- docaine, the range for INap was 5-20 μmol/L and for INaT was 0. 05-2 mmol/L. Conclusion： INap and INaT were suppressed by different concentrations of lidocaine. INap was suppressed by very low concentration of lidocaine （5-20 μmol/L）. However, INaT could only be blocked by high concentration of lidocaine （0.05-2 mmol/L）.展开更多
A theoretical equation is developed which describes the response of the current transients to a constant potential at tubular electrodes for a reversible electrode reaction in the flowing fluid.
Urban rail transit is one of the most important way for urban residents. However, frequent power failure, especially the short fault hinders the safe and stable operation of rail transit. The research of the transient...Urban rail transit is one of the most important way for urban residents. However, frequent power failure, especially the short fault hinders the safe and stable operation of rail transit. The research of the transient variation of line electrical parameters in short circuit fault is the basis of researches for technology of line protection and short circuit fault location. Based on Matlab/Simulink, a 24-pulse rectifier circuit model is established, the resistance and inductance value of the catenary and rail network are calculated. The short Circuit fault simulation model of DC traction power supply system is established. The short-circuit fault of the traction network at close and distant points are simulated, the transient variation values of fault current with the different fault distance are analyzed. The simulation results show that the transient current peak of the nearby short circuit is oscillatory and convergent due to the nonlinear devices, which proves the accuracy of the model and provides a reference for the precise configuration of the line protection equipment.展开更多
Modular multilevel converters(MMCs)have limited ability to withstand overcurrent.Additionally,the complex characteristics of faults make it extremely difficult to reliably identify the fault area within a short period...Modular multilevel converters(MMCs)have limited ability to withstand overcurrent.Additionally,the complex characteristics of faults make it extremely difficult to reliably identify the fault area within a short period.In this paper,the waveform of the transient current component is transformed into multiple intersecting curves in an alternative coordinate system,utilizing the principle of coordinate mapping.The internal and external faults are identified by determining the range of angles between the current waveforms and the time axis based on the intersecting regions of the curves.Subsequently,a unit protection scheme based on the transient current coordinate mapping interval is proposed.Finally,a modular multi-level converter-high voltage direct current(MMC-HVDC)system is built using PSCAD/EMTDC to validate the proposed scheme.The simulation results show that the proposed protection scheme is insensitive to factors such as current fluctuations caused by noise and distributed capacitive currents.In addition,it shows high robustness against fault resistance.展开更多
In this paper, the boundary value problem (BVP) of 3 D transient eddy current field in the end region in the case that the generator is affected by impact load is specified. Besides, ways to implement discrete method...In this paper, the boundary value problem (BVP) of 3 D transient eddy current field in the end region in the case that the generator is affected by impact load is specified. Besides, ways to implement discrete methods in both time domain and space domain during the solution of the problem are investigated. The Crank Nicolson scheme is utilized to attain the iterative format of time differential, after taking factors that can ensure both computation precision and stability into consideration. In this paper, the magnetic distribution in the end region of a turbogenerator in the case that the generator is affected by impact load is specified. As a result, it provides foundation for further study of electromagnetic force and electromagnetic vibration in the end region of the turbogenerator.展开更多
Electrical conduction behavior of pristine and iodine doped polyetherimides （PEI） has been investigated under both transient and steady state conditions in the operating temperature range 50-200℃ at various electri...Electrical conduction behavior of pristine and iodine doped polyetherimides （PEI） has been investigated under both transient and steady state conditions in the operating temperature range 50-200℃ at various electric fields of 12-60 kV/cm. The transient currents show the hyperbolic decay character, and the decay exponent p （a measure of current decay rate） decreases with temperature （T） and doping concentration. The origin of transient currents has been attributed to the dipolar nature of carbonyl （〉C：O） groups and the ether linkages present in the main chain of PEI. The low field steady state conduction is ohmic in nature. The magnitudes of ionic jump distance （a） values do not favor an ionic type of conduction as a possible conduction mechanism in pristine as well as iodine doped PEI. The Schottky coefficients estimations do not show the possibility of Schottky type or Poole-Frenkel type conduction mechanisms in the low temperature region （〈 120℃）, however, in the high temperature region （〉 120℃） there is a certain possibility of Poole- Frenkel type conduction mechanism in both pristine and iodine doped samples. The dual slope in the lg/versus 1/T curves for iodine doped samples indicates the presence of more than one type of trapping levels.展开更多
The present study was designed to determine the effects of Guanfu base A(GFA) on the late sodium current(INa.L),transient sodium current(INa.T),HERG current(IHERG),and Kv1.5 current(IKv1.5).The values of INa.L,INa.T,I...The present study was designed to determine the effects of Guanfu base A(GFA) on the late sodium current(INa.L),transient sodium current(INa.T),HERG current(IHERG),and Kv1.5 current(IKv1.5).The values of INa.L,INa.T,IHERG and IKv1.5 were recorded using the whole-cell patch clamp technique.Compared with other channels,GFA showed selective blocking activity in late sodium channel.It inhibited INa.L in a concentration-dependent manner with an IC50 of(1.57 ± 0.14) μmol·L-1,which was significantly lower than its IC50 values of(21.17 ± 4.51) μmol·L-1 for the INa.T.The inhibitory effect of GFA on INa,L was not affected by 200μmol·L-1 H2O2.It inhibited IHERG with an IC50 of(273 ± 34) μmol·L-1 and has slight blocking effect on IKv1.5,decreasing IKv1.5 by only 20.6% at 200 μmol·L-1.In summary,GFA inhibited INa.L selectively and remained similar inhibition in presence of reactive oxygen species..These findings may suggest a novel molecular mechanism for the potential clinical application of GFA in the treatment of cardiovascular disorders.展开更多
Single-phase low current grounding faults areoften seen in power distribution system of coal mines.These faults are difficult to reliably identify.We propose a new method of single-phase ground fault protection based ...Single-phase low current grounding faults areoften seen in power distribution system of coal mines.These faults are difficult to reliably identify.We propose a new method of single-phase ground fault protection based upon a discernible matrix of the fractal dimension associated with line currents.The method builds on existing selective protection methods.Faulted feeders are distinguished using differences in the zero-sequence transient current fractal dimension.The current signals were first processed through a fast Fourier transform and then the characteristics of a faulted line were identified using a discernible matrix.The method of calculation is illustrated.The results show that the method involves simple calculations, is easy to do and is highly accurate.It is, therefore, suitable for distribution networks having different neutral grounding modes.展开更多
Background Some studies have confirmed that the right ventricular walls of most rodents, such as canines and humans, have evident transient outward potassium current (I to1) heterogeneity, and this heterogeneity i...Background Some studies have confirmed that the right ventricular walls of most rodents, such as canines and humans, have evident transient outward potassium current (I to1) heterogeneity, and this heterogeneity is closely related to J point elevation, J wave formation, and some ventricular tachycardias such as ventricular fibrillations caused by Brugada syndrome. This study is designed to investigate transmural electrical heterogeneity of the canine right ventricle during repolarization (phase 1) from the viewpoint of 4-aminopyridine sensitive and calcium-independent I to1. Methods Adult canine single right ventricular epicardial (Epi) cells, mid-myocardial (M) cells, and endocardial (Endo) cells were enzymatically dissociated. Whole cell voltage-clamp recordings were made to compare the I to1 values of the three cell types. Results At 37℃ and using 0.2 Hz and +70 mV depolarizing test potentials, the average peak I to1 values of Epi cells and M cells averaged (4070±1720) pA and (3540±1840) pA, respectively. The activated and inactivated Epi and M cells kinetic processes were in accordance with the Boltzmann distribution. Compared with I to1 in Epi cells and M cells, the average peak I to1 in Endo cells was very low, averaged (470±130) pA. Conclusions These results suggest that there are evident differences and potent gradients in I to1 between the three cardiac cell types, especially between Epi and Endo cells. These differences are among the prominent manifestations of right ventricular electrical heterogeneity, and may form an important ionic basis and prerequisite for some malignant arrhythmias in the right ventricle, including those arising from Brugada syndrome and other diseases.展开更多
Carbon dots(CDs),as a unique zero-dimensional member of carbon materials,have attracted numerous attentions for their potential applications in optoelectronic,biological,and energy related fields.Recently,CDs as catal...Carbon dots(CDs),as a unique zero-dimensional member of carbon materials,have attracted numerous attentions for their potential applications in optoelectronic,biological,and energy related fields.Recently,CDs as catalysts for energy conversion reactions under multi-physical conditions such as light and/or electricity have grown into a research frontier due to their advantages of high visible light utilization,fast migration of charge carriers,efficient surface redox reactions and good electrical conductivity.In this review,we summarize the fabrication methods of CDs and corresponding CD nanocomposites,including the strategies of surface modification and heteroatom doping.The properties of CDs that concerned to the photo-and electro-catalysis are highlighted and detailed corresponding applications are listed.More importantly,as new non-contact detection technologies,transient photo-induced voltage/current have been developed to detect and study the charge transfer kinetics,which can sensitively reflect the complex electron separation and transfer behavior in photo-/electro-catalysts.The development and application of the techniques are reviewed.Finally,we discuss and outline the major challenges and opportunities for future CD-based catalysts,and the needs and expectations for the development of novel characterization technologies.展开更多
文摘The transmural heterogeneous changes of transient outward potassium currents (Ito) in rabbit hypertrophic cardiaomyocytes and the effects of long-term prophylactic treatment with volsartan were investigated. Rabbits were divided into hypertrophy group (left ventricular hypertrophy induced by partial ligation of abdominal aorta), vol-treated group (volsartan was administrated after the ligation), and control group (sham operated). Myocytes were isolated by a two-step enzymatical method. The sub-endocardial (Endo) and sub-epicardium (Epi) tissues were separated from midmyocardium (Mid) with a razor. Whole-cell patch-clamp technique was used to record potassium currents. The results showed that membrane capacitance was larger in hypertrophic cells than those in control and vol-treated cells (P<0.01 vs control cells, n=30). The densities of Ito in hypertrophic cells were reduced by sub-epicardium (Epi) (27.8±2.9) %, midmyocardium (Mid) (41.0±4.7) %, and sub-endocardium (Endo) (20.3±3.4) % compared with those in control cells. The decrease of Ito density was more pronounced in Mid than in Epi and Endo (P<0.01 vs Epi or Endo). There were no significant differences in Ito densities between vol-treated group and control group in three layers separately. In conclusion, volsartan can inhibit the transmural heterogeneous changes of Ito in left ventricular hypertrophic cardiomyocytes in rabbit.
基金financial support from the National Natural Science Foundation of China(No.51974198)。
文摘To address the problem of floating and aggregation of Ag-GNSs in the molten pool during the traditional reflow soldering process,Cu/SAC/Ag-GNSs/Cu sandwich joints were prepared under an applied current density(1.0×10^(4) A/cm^(2))for a few hundred milliseconds to produce Ag-coated graphene-reinforced Sn-Ag-Cu(SAC/AgGNSs)solder joints.The experimental results showed that Ag-GNSs were homogenously dispersed in the solder joints,providing more Cu6 Sn5 grain nucleation sites,which refined these grains and reduced the thickness difference at the anode and cathode.In addition,the Cu6 Sn5 morphology changed from rod-like to plate-shaped because of the uniform distribution of Ag-GNSs and constitutional supercooling.The significantly increased shear strength of the transient current bonding and the change in the fracture mechanism were due to the uniformly distributed Ag-GNSs and the microstructural changes.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50807001)
文摘The electromagnetic concentrative coils are indispensable in the functional magnetic stimulation and have potential applications in nondestructive testing. In this paper, we propose a figure-8-shaped coil being composed of two arbitrary oblique elliptical coils, which can change the electromagnetic concentrative region and the magnitude of eddy current density by changing the elliptical shape and/or spread angle between two elliptical coils. Pulsed current is usually the excitation source in the functional magnetic stimulation, so in this paper we derive the analytical solutions of transient pulsed eddy current field in the time domain due to the elliptical concentrative coil placed in an arbitrary position over a half-infinite plane conductor by making use of the scale-transformation, the Laplace transform and the Fourier transform are used in our derivation. Calculation results of field distributions produced by the figure-8-shaped elliptical coil show some behaviours as follows： 1） the eddy currents are focused on the conductor under the geometric symmetric centre of figure-8-shaped coil; 2） the greater the scale factor of ellipse is, the higher the eddy current density is and the wider the concentrative area of eddy current along y axis is; 3） the maximum magnitude of eddy current density increases with the increase of spread angle. When spread angle is 180°, there are two additional reverse concentrative areas on both sides of x axis.
基金Supported by National Natural Science Foundation of China(No. 60674111)
文摘Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The experiment revealed that the amplitude of transient outward potassium channel current was reduced.The maximum activated current densities of control group and exposure group were 163.62±20.68 pA/pF and 98.74±16.57 pA/pF(n=12,P<0.01) respectively.The static magnetic field exposure affected the activation and inactivation process of transient outward potassium channel current.Due to the magnetic field exposure,the half-activation voltage of the activation curves changed from 5.59±1.96 mV to 27.87±7.24 mV(n=12,P<0.05) ,and the slope factor changed from 19.43±2.11 mV to 25.87±4.22 mV(n=12,P<0.05) .The half-inactivation voltage of the inactivation curves also changed from-56.09±0.89 mV to-57.16±1.10 mV(n=12,P>0.05) and the slope factor of the inactivation curves from 8.69±0.80 mV to 10.87±1.02 mV(n=12,P<0.05) .The results show that the static magnetic field can change the characteristics of transient outward K+ channel,and affect the physiological functions of neurons.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61274106 and 61574171
文摘Silicon-germanium （SiGe） hereto-junction bipolar transistor current transients induced by pulse laser and heavy iron are measured using a real-time digital oscilloscope. These transients induced by pulse laser and heavy iron exhibit the same waveform and charge collection time except for the amplitude of peak current. Different laser energies and voltage biases under heavy ion irradiation also have impact on current transient, whereas the waveform remains unchanged. The position-correlated current transients suggest that the nature of the current transient is controlled by the behavior of the C/S junction.
文摘The transient current behaviour for Iron in 3.5%NaCl and 3.5%NaCl +1%NaNO2 solutions during corrosion fatigue (CF) process has been investigated at different given strain amplitudes and strain rates. The results show that elastic strain has little contribution to material dissolution. The elastic tension strain results in the decrease in the transient current, while the elastic compression strain increases the transient current. Compared to the elastic deformation, plastic deformation affects material dissolution evidently For iron in 3.5%NaCl solution, the strain amplitude plays a dominant role in the dissolution process accelerated by the plastic strain, while in 3.5%NaCl+1%NaNO2 solution, both the strain amplitude and strain rate play an important role in this process. In this paper, the effect of the elastic deformation on the material dissolution and the relation between the tension and compression current peak values under the plastic cycle deformation are discussed
基金supported by the National Natural Science Foundation of China(Grant No.51307124)the Major Program of the National Natural Science Foundation of China(Grant No.51190105)
文摘A novel transient rotor current control scheme is proposed in this paper for a doubly-fed induction generator（DFIG）equipped with a superconducting magnetic energy storage（SMES） device to enhance its transient voltage and frequency support capacity during grid faults. The SMES connected to the DC-link capacitor of the DFIG is controlled to regulate the transient dc-link voltage so that the whole capacity of the grid side converter（GSC） is dedicated to injecting reactive power to the grid for the transient voltage support. However, the rotor-side converter（RSC） has different control tasks for different periods of the grid fault. Firstly, for Period I, the RSC injects the demagnetizing current to ensure the controllability of the rotor voltage. Then, since the dc stator flux degenerates rapidly in Period II, the required demagnetizing current is low in Period II and the RSC uses the spare capacity to additionally generate the reactive（priority） and active current so that the transient voltage capability is corroborated and the DFIG also positively responds to the system frequency dynamic at the earliest time. Finally, a small amount of demagnetizing current is provided after the fault clearance. Most of the RSC capacity is used to inject the active current to further support the frequency recovery of the system. Simulations are carried out on a simple power system with a wind farm. Comparisons with other commonly used control methods are performed to validate the proposed control method.
基金Project supported in part by the National Natural Science Foundation of China(Grant No.61974056)the Natural Science Foundation of Shanghai(Grant No.19ZR1471300)+1 种基金Shanghai Science and Technology Innovation Action Plan(Grant No.19511131900)Shanghai Science and Technology Explorer Plan(Grant No.21TS1401700)。
文摘The single event transient(SET)effect in nanotube tunneling field-effect transistor with bias-induced electron–hole bilayer(EHBNT-TFET)is investigated by 3-D TCAD simulation for the first time.The effects of linear energy transfer(LET),characteristic radius,strike angle,electrode bias and hit location on SET response are evaluated in detail.The simulation results show that the peak value of transient drain current is up to 0.08 m A for heavy ion irradiation with characteristic radius of 50 nm and LET of 10 Me V·cm^(2)/mg,which is much higher than the on-state current of EHBNTTFET.The SET response of EHBNT-TFET presents an obvious dependence on LET,strike angle,drain bias and hit location.As LET increases from 2 Me V·cm^(2)/mg to 10 Me V·cm^(2)/mg,the peak drain current increases monotonically from 0.015 mA to 0.08 mA.The strike angle has an greater impact on peak drain current especially for the smaller characteristic radius.The peak drain current and collected charge increase by 0.014 mA and 0.06 fC,respectively,as the drain bias increases from 0.1 V to 0.9 V.Whether from the horizontal or the vertical direction,the most sensitive hit location is related to wt.The underlying physical mechanism is explored and discussed.
基金This work was supported by Leading Specialty Funding of Shanghai, Grant No.94- III- 001.
文摘To determine the effects of HOE 694, a new and potent Na＋- H＋ exchanger blocker, on transient inward current (Iti) and Na＋- Ca2＋ exchange during hypoxia- reoxygenation in guinea pig cardiomyocytes. Methods. Cardiomyocytes were isolated from adult guinea pig ventricle. Experiment was performed in an experimental chamber that allowed the cells to be exposed to a sufficiently low O2 pressure. The cells were subjected to hypoxia and reoxygenation. The ionic currents were studied with patch clamp technique. Results. In the absence of HOE 694, hypoxia- reoxygenation induced Iti in 12 of 15 experiments; but in cardiomyocytes pretreated with HOE 694 (10～ 50μ mol/L), the incidence of Iti observed during reoxygenation was reduced to 5 of 11 experiments and 3 of 10 experiments, P Conclusions. Blockade of the Na＋- H＋ exchange by HOE 694 could reduce Ca2＋ overload upon hypoxia- reoxygenation, and inhibition of Na＋- H＋ exchange may also indirectly decrease Na＋- Ca2＋ exchange activity during hypoxia.
基金the National Natural Science Foundation of China(No.30600581)
文摘Objective ：To investigate the different suppressive effect of lidocaine on persistent Na^＋ current and transient Na^＋ current in injured or uninjured dorsal root ganglion neurons. Methods： Totally 23 SD rats were randomly divided into 2 groups： control group （n： 10） and chronically compressed DRG （dorsal root ganglion） group （CCD group, n= 13）. Rats were anesthetized and DRG was isolated. Single DRG neuron was isolated by enzymatic disassociation method. Persistent Na^＋ current （INap） and transient Na^＋ current （INaT） were elicited in voltage clamp mode. Results： The presence of INap was testified in most DRG neurons （38/46 neurons in CCD group and 31/39 neurons in control group, P〉0. 05）. However, the cur- rent density of INap in CCD group （4. 6±0. 6 pA/pF, n=38 neurons） was greater than that in control group （2.5±0.4 pA/pF, n=31 neurons） （P〈0. 05）. The characteristics of INap was observed and found that INap could he blocked by 0.2 μmol/L tetrodotoxin easily. Furthermore, the does-effect relationship of lidocaine on INaP and IN.T were also examined. INaP and IN.T were suppressed by different concentrations of li- docaine, the range for INap was 5-20 μmol/L and for INaT was 0. 05-2 mmol/L. Conclusion： INap and INaT were suppressed by different concentrations of lidocaine. INap was suppressed by very low concentration of lidocaine （5-20 μmol/L）. However, INaT could only be blocked by high concentration of lidocaine （0.05-2 mmol/L）.
文摘A theoretical equation is developed which describes the response of the current transients to a constant potential at tubular electrodes for a reversible electrode reaction in the flowing fluid.
文摘Urban rail transit is one of the most important way for urban residents. However, frequent power failure, especially the short fault hinders the safe and stable operation of rail transit. The research of the transient variation of line electrical parameters in short circuit fault is the basis of researches for technology of line protection and short circuit fault location. Based on Matlab/Simulink, a 24-pulse rectifier circuit model is established, the resistance and inductance value of the catenary and rail network are calculated. The short Circuit fault simulation model of DC traction power supply system is established. The short-circuit fault of the traction network at close and distant points are simulated, the transient variation values of fault current with the different fault distance are analyzed. The simulation results show that the transient current peak of the nearby short circuit is oscillatory and convergent due to the nonlinear devices, which proves the accuracy of the model and provides a reference for the precise configuration of the line protection equipment.
基金supported by the Tianshan Talent Training Program(No.2022TSYCLJ0019)the National Key R&D Program of China(No.2021YFB1507000)+1 种基金the Excellent Doctoral Research and Innovation Project of Xinjiang University(No.XJU2022BS094)the Natural Science Foundation of Xinjiang Uygur Autonomous Region Sponsored Programs(No.2022D01C662).
文摘Modular multilevel converters(MMCs)have limited ability to withstand overcurrent.Additionally,the complex characteristics of faults make it extremely difficult to reliably identify the fault area within a short period.In this paper,the waveform of the transient current component is transformed into multiple intersecting curves in an alternative coordinate system,utilizing the principle of coordinate mapping.The internal and external faults are identified by determining the range of angles between the current waveforms and the time axis based on the intersecting regions of the curves.Subsequently,a unit protection scheme based on the transient current coordinate mapping interval is proposed.Finally,a modular multi-level converter-high voltage direct current(MMC-HVDC)system is built using PSCAD/EMTDC to validate the proposed scheme.The simulation results show that the proposed protection scheme is insensitive to factors such as current fluctuations caused by noise and distributed capacitive currents.In addition,it shows high robustness against fault resistance.
文摘In this paper, the boundary value problem (BVP) of 3 D transient eddy current field in the end region in the case that the generator is affected by impact load is specified. Besides, ways to implement discrete methods in both time domain and space domain during the solution of the problem are investigated. The Crank Nicolson scheme is utilized to attain the iterative format of time differential, after taking factors that can ensure both computation precision and stability into consideration. In this paper, the magnetic distribution in the end region of a turbogenerator in the case that the generator is affected by impact load is specified. As a result, it provides foundation for further study of electromagnetic force and electromagnetic vibration in the end region of the turbogenerator.
基金financially supported by DRDO,Government of India,New Delhi
文摘Electrical conduction behavior of pristine and iodine doped polyetherimides （PEI） has been investigated under both transient and steady state conditions in the operating temperature range 50-200℃ at various electric fields of 12-60 kV/cm. The transient currents show the hyperbolic decay character, and the decay exponent p （a measure of current decay rate） decreases with temperature （T） and doping concentration. The origin of transient currents has been attributed to the dipolar nature of carbonyl （〉C：O） groups and the ether linkages present in the main chain of PEI. The low field steady state conduction is ohmic in nature. The magnitudes of ionic jump distance （a） values do not favor an ionic type of conduction as a possible conduction mechanism in pristine as well as iodine doped PEI. The Schottky coefficients estimations do not show the possibility of Schottky type or Poole-Frenkel type conduction mechanisms in the low temperature region （〈 120℃）, however, in the high temperature region （〉 120℃） there is a certain possibility of Poole- Frenkel type conduction mechanism in both pristine and iodine doped samples. The dual slope in the lg/versus 1/T curves for iodine doped samples indicates the presence of more than one type of trapping levels.
基金supported by the Fundamental Research Funds for the Central Universities(No.JKZ2011007)the National "Key Program for New Drug Research Development"(No.2009 ZX09103-345)
文摘The present study was designed to determine the effects of Guanfu base A(GFA) on the late sodium current(INa.L),transient sodium current(INa.T),HERG current(IHERG),and Kv1.5 current(IKv1.5).The values of INa.L,INa.T,IHERG and IKv1.5 were recorded using the whole-cell patch clamp technique.Compared with other channels,GFA showed selective blocking activity in late sodium channel.It inhibited INa.L in a concentration-dependent manner with an IC50 of(1.57 ± 0.14) μmol·L-1,which was significantly lower than its IC50 values of(21.17 ± 4.51) μmol·L-1 for the INa.T.The inhibitory effect of GFA on INa,L was not affected by 200μmol·L-1 H2O2.It inhibited IHERG with an IC50 of(273 ± 34) μmol·L-1 and has slight blocking effect on IKv1.5,decreasing IKv1.5 by only 20.6% at 200 μmol·L-1.In summary,GFA inhibited INa.L selectively and remained similar inhibition in presence of reactive oxygen species..These findings may suggest a novel molecular mechanism for the potential clinical application of GFA in the treatment of cardiovascular disorders.
基金Project 50504015 supported by the National Natural Science Foundation of Chinathe Youth Science and Technology Research Program of China University of Mining and Technology (0C060996)
文摘Single-phase low current grounding faults areoften seen in power distribution system of coal mines.These faults are difficult to reliably identify.We propose a new method of single-phase ground fault protection based upon a discernible matrix of the fractal dimension associated with line currents.The method builds on existing selective protection methods.Faulted feeders are distinguished using differences in the zero-sequence transient current fractal dimension.The current signals were first processed through a fast Fourier transform and then the characteristics of a faulted line were identified using a discernible matrix.The method of calculation is illustrated.The results show that the method involves simple calculations, is easy to do and is highly accurate.It is, therefore, suitable for distribution networks having different neutral grounding modes.
文摘Background Some studies have confirmed that the right ventricular walls of most rodents, such as canines and humans, have evident transient outward potassium current (I to1) heterogeneity, and this heterogeneity is closely related to J point elevation, J wave formation, and some ventricular tachycardias such as ventricular fibrillations caused by Brugada syndrome. This study is designed to investigate transmural electrical heterogeneity of the canine right ventricle during repolarization (phase 1) from the viewpoint of 4-aminopyridine sensitive and calcium-independent I to1. Methods Adult canine single right ventricular epicardial (Epi) cells, mid-myocardial (M) cells, and endocardial (Endo) cells were enzymatically dissociated. Whole cell voltage-clamp recordings were made to compare the I to1 values of the three cell types. Results At 37℃ and using 0.2 Hz and +70 mV depolarizing test potentials, the average peak I to1 values of Epi cells and M cells averaged (4070±1720) pA and (3540±1840) pA, respectively. The activated and inactivated Epi and M cells kinetic processes were in accordance with the Boltzmann distribution. Compared with I to1 in Epi cells and M cells, the average peak I to1 in Endo cells was very low, averaged (470±130) pA. Conclusions These results suggest that there are evident differences and potent gradients in I to1 between the three cardiac cell types, especially between Epi and Endo cells. These differences are among the prominent manifestations of right ventricular electrical heterogeneity, and may form an important ionic basis and prerequisite for some malignant arrhythmias in the right ventricle, including those arising from Brugada syndrome and other diseases.
基金supported by National MCF Energy R&D Program of China(2018YFE0306105)National Key R&D Program of China(2020YFA0406104,2020YFA0406101)+6 种基金Innovative Research Group Project of the National Natural Science Foundation of China(51821002)National Natural Science Foundation of China(51725204,21771132,51972216,52041202,51902217)Natural Science Foundation of Jiangsu Province(BK20190041)Key-Area Research and Development Program of GuangDong Province(2019B010933001)Collaborative Innovation Center of Suzhou Nano Science and Technologythe 111 ProjectSuzhou Key Laboratory of Functional Nano and Soft Materials。
文摘Carbon dots(CDs),as a unique zero-dimensional member of carbon materials,have attracted numerous attentions for their potential applications in optoelectronic,biological,and energy related fields.Recently,CDs as catalysts for energy conversion reactions under multi-physical conditions such as light and/or electricity have grown into a research frontier due to their advantages of high visible light utilization,fast migration of charge carriers,efficient surface redox reactions and good electrical conductivity.In this review,we summarize the fabrication methods of CDs and corresponding CD nanocomposites,including the strategies of surface modification and heteroatom doping.The properties of CDs that concerned to the photo-and electro-catalysis are highlighted and detailed corresponding applications are listed.More importantly,as new non-contact detection technologies,transient photo-induced voltage/current have been developed to detect and study the charge transfer kinetics,which can sensitively reflect the complex electron separation and transfer behavior in photo-/electro-catalysts.The development and application of the techniques are reviewed.Finally,we discuss and outline the major challenges and opportunities for future CD-based catalysts,and the needs and expectations for the development of novel characterization technologies.
