Objective:This study aimed to develop expert fuzzy logic model to assist physicians in the prediction of postoperative complications of prostatic hyperplasia before surgery.Methods:A method for classification of surgi...Objective:This study aimed to develop expert fuzzy logic model to assist physicians in the prediction of postoperative complications of prostatic hyperplasia before surgery.Methods:A method for classification of surgical risks was developed.The effect of rotation of the current–voltage characteristics at biologically active points(acupuncture points)was used for the formation of classifier descriptors.The effect determined reversible and non-reversible changes in electrical resistance at acupuncture points with periodic exposure to a sawtooth probe current.Then,the developed method was tested on the prediction of the success of surgical treatment of benign prostatic hyperplasia.Results:Input descriptors were obtained from collected data including current-voltage characteristics of 5 acupuncture points and composed of 27 arrays feeding in the model.The maximum diagnostic sensitivity of the classifier for the success of a surgical operation in the control sample was 88%and for testing data set prediction accuracy was 97%.Conclusion:The use of tuples of current-voltage characteristic descriptors of acupuncture points in the classifiers could be used to predict the success of surgical treatment with satisfactory accuracy.The model can be a valuable tool to support physicians’diagnosis.展开更多
Polycrystalline La0.67Ba0.33MnO3 bulk samples were annealed in flowing 95%Ar：5%H2 （AH） mixed gas at 973 K for different time respectively. The influence of the annealing time on the current-voltage properties was s...Polycrystalline La0.67Ba0.33MnO3 bulk samples were annealed in flowing 95%Ar：5%H2 （AH） mixed gas at 973 K for different time respectively. The influence of the annealing time on the current-voltage properties was systematically investigated. Linear current-voltage characteristics were observed in the as-prepared and the 10 h annealed samples, and nonlinear current-voltage characteristics was found in the 100 h annealed sample. At the same time, segregation of impurity phase and micro-cracks were found on the surfaces of the 100 h annealed samples, which was testified to be Ba ion impurity. Analysis showed that the changes of electronic properties were caused by barium ion im-purities and micro-cracks in the 100 h annealed sample.展开更多
Current-voltage electrical behavior of in situ microfibrillar carbon black （CB）/poly（ethylene terephthalate） （PET）/polyethylene （PE） （m-CB/PET/PE） composites with various CB concentrations at ambient tempera...Current-voltage electrical behavior of in situ microfibrillar carbon black （CB）/poly（ethylene terephthalate） （PET）/polyethylene （PE） （m-CB/PET/PE） composites with various CB concentrations at ambient temperatures was studied under a direct-current electric field. The current-voltage （l-V） curves exhibited nonlinearity beyond a critical value of voltage. The dynamic random resistor network （DRRN） model was adopted to semi-qualitatively explain the nonlinear conduction behavior of m-CB/PET/PE composites. Macroscopic nonlinearity originated from the interfacial interactions between CB/PET micro fibrils and additional conduction channels. Combined with the special conductive networks, an illustration was proposed to interpret the nonlinear 1-V characteristics by a field emission or tunneling mechanism between CB particles in the CB/PET micro fibers intersections.展开更多
Some electrical parameters of the SIS-type hysteretic underdamped Josephson junction(JJ)can be measured by its current-voltage characteristics(IVCs).Currents and voltages at JJ are commensurate with the intrinsic nois...Some electrical parameters of the SIS-type hysteretic underdamped Josephson junction(JJ)can be measured by its current-voltage characteristics(IVCs).Currents and voltages at JJ are commensurate with the intrinsic noise level of measuring instruments.This leads to the need for multiple measurements with subsequent statistical processing.In this paper,the digital algorithms are proposed for the automatic measurement of the JJ parameters by IVC.These algorithms make it possible to implement multiple measurements and check these JJ parameters in an automatic mode with the required accuracy.The complete sufficient statistics are used to minimize the root-mean-square error of parameter measurement.A sequence of current pulses with slow rising and falling edges is used to drive JJ,and synchronous current and voltage readings at JJ are used to realize measurement algorithms.The algorithm performance is estimated through computer simulations.The significant advantage of the proposed algorithms is the independence from current source noise and intrinsic noise of current and voltage meters,as well as the simple implementation in automatic digital measuring systems.The proposed algorithms can be used to control JJ parameters during mass production of superconducting integrated circuits,which will improve the production efficiency and product quality.展开更多
It is shown that the nonideality coefficient m actually depends on the electron temperature Te, and the hole temperature Th. We get more general expression for the nonideality coefficient, taking into account the conc...It is shown that the nonideality coefficient m actually depends on the electron temperature Te, and the hole temperature Th. We get more general expression for the nonideality coefficient, taking into account the concentration of electrons and holes, as well as their temperature, coefficient and diffusion length, the temperature of the phonons, the applied voltage, and the height of the potential barrier.展开更多
The factors influencing the current-voltage（I-V） characteristics of light-emitting diodes（LEDs） are investigated to reveal the connection of I-V characteristics under optical excitation and those under electrical ...The factors influencing the current-voltage（I-V） characteristics of light-emitting diodes（LEDs） are investigated to reveal the connection of I-V characteristics under optical excitation and those under electrical excitation.By inspecting the I-V curves under optical and electrical excitation at identical injection current,it has been found that the I-V curves exhibit apparent differences in voltage values.Furthermore,the differences are found to originate from the junction temperatures in diverse excitation ways.Experimental results indicate that if the thermal effect of illuminating spot is depressed to an ignorable extent by using pulsed light,the junction temperature will hardly deflect from that under optical excitation,and then the I-V characteristics under two diverse excitation ways will be the same.展开更多
A high performance AlAs/In0.53 Ga0.47 As/InAs resonant tunneling diode （RTD） on InP substrate is fabricated by inductively coupled plasma etching. This RTD has a peak-to-valley current ratio （PVCR） of 7. 57 and a ...A high performance AlAs/In0.53 Ga0.47 As/InAs resonant tunneling diode （RTD） on InP substrate is fabricated by inductively coupled plasma etching. This RTD has a peak-to-valley current ratio （PVCR） of 7. 57 and a peak current density Jp = 39.08kA/cm^2 under forward bias at room temperature. Under reverse bias, the corresponding values are 7.93 and 34.56kA/cm^2 . A resistive cutoff frequency of 18.75GHz is obtained with the effect of a parasitic probe pad and wire. The slightly asymmetrical current-voltage characteristics with a nominally symmetrical structure are also discussed.展开更多
A full-coupling model on the current-voltage(J-V)characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconduct...A full-coupling model on the current-voltage(J-V)characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconductor(M/S)contacts.The depletion layer assumption proposed by the Shockley model is discarded.Gauss’law on the electric potential and the electric field is applied in the whole junction region such that the majority-carrier currents inside and outside the P/N barrier region are able to be exactly defined and clearly calculated.Then,the stable continuity equations of the electron and hole currents are established to show the current conversion between minority-and majority-carriers inside the whole PN junction region.By analyzing all the conversion procedure,the J-V characteristics of a PN junction are obtained with good agreement to the experimental results,which are closely dependent on the minority-carrier lifetime and doping concentrations.Obviously,the study on this topic possesses referential significance to mechanically tuning the performance of piezoelectric PN junctions and piezotronic devices.展开更多
Nitrogen-doped nanocrystalline diamond films(N-NDFs)have been deposited on p-type silicon(Si)by microwave plasma chemical vapor deposition.The reaction gases are methane,hydrogen,and nitrogen without the conventional ...Nitrogen-doped nanocrystalline diamond films(N-NDFs)have been deposited on p-type silicon(Si)by microwave plasma chemical vapor deposition.The reaction gases are methane,hydrogen,and nitrogen without the conventional argon(Ar).The N-NDFs were characterized by X-ray diffraction,Raman spectroscopy,and scanning electron microscopy.The grain sizes are of 8~10 nm in dimension.The N-NDF shows n-type behavior and the corresponding N-NDF/p-Si heterojunction diodes are realized with a high rectification ratio of 102 at^7.8 V,and the current density reaches to1.35 A/cm2 at forward voltage of 8.5 V.The findings suggest that fabricated by CH_4/H_2/N_2 without Ar,the N-NDFs and the related rectifying diodes are favorable for achieving high performance diamond-based optoelectronic devices.展开更多
The Langmuir Probe(LAP), onboard the China Seismo-Electromagnetic Satellite(CSES), has been designed for in situ measurements of bulk parameters of the ionosphere plasma, the first Chinese application of in-situ measu...The Langmuir Probe(LAP), onboard the China Seismo-Electromagnetic Satellite(CSES), has been designed for in situ measurements of bulk parameters of the ionosphere plasma, the first Chinese application of in-situ measurement technology in the field of space exploration. The two main parameters measured by LAP are electron density and temperature. In this paper, a brief description of the LAP and its work mode are provided. Based on characteristics of the LAP, and assuming an ideal plasma environment, we introduce in detail a method used to invert the I-V curve; the data products that can be accessed by users are shown. Based on the LAP data available, this paper reports that events such as earthquakes and magnetic storms are preceded and followed by obvious abnormal changes. We suggest that LAP could provide a valuable data set for studies of space weather, seismic events, and the ionospheric environment.展开更多
Terbium-picrate triethylene glycol（EO3-Tb-Pic） complex was prepared in thin film and single layer device structure of ITO/EO3-Tb-Pic/Al, using spin coating technique. The UV-Vis absorption spectroscopy analysis was ...Terbium-picrate triethylene glycol（EO3-Tb-Pic） complex was prepared in thin film and single layer device structure of ITO/EO3-Tb-Pic/Al, using spin coating technique. The UV-Vis absorption spectroscopy analysis was performed to evaluate the electronic molecular transition of the complex. The optical band gap, Eg estimated from the Tauc model revealed that EO3-Tb-Pic thin film exhibited a direct transition with Eg of 2.70 eV. The electronic parameters of the ITO/EO3-Tb-Pic/Al device such as the ideality factor n, barrier height Φb, saturation current Io, and series resistance Rs, were extracted from the conventional lnI-V, Cheung＇s functions and Norde＇s method. It was found that the evaluated parameters calculated from Norde＇s and Cheung＇s methods were consistent with those calculated from the conventional I-V method. In the double logarithmic I-V plot, three distinct regions based on the slope were identified, and the conduction mechanisms were discussed and explained. The mobility, μ value was estimated from SCLC region as 2.58×10^–7 cm2/（V·s）. This newly obtained lanthanide complex may be potentially utilized in electronic devices.展开更多
This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation proces...This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation process on a bipolar membrane based on the existence of a depletion layer and Onsager's theory. Particular attention was given to the influence of applied voltage on depletion thickness and the dissociation constant. The factors on the water splitting process, such as water diffusivity, water content, ion exchange capacity, temperature, relative permittivity, etc. Were adequately analysed based on the derived model equations and several suggestions were proposed for decreasing the applied voltage in practical operation. The water dissociation tests were conducted and compared with both the theoretical calculation and the measured current-voltage curves reported in the literature, which showed a very good prediction to practical current-voltage behavior of a bipolar membrane at high current densities when the splitting of water actually commenced.展开更多
Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology develop...Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick＇s model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.展开更多
By using high-temperature deep-level transient spectroscopy （HT-DLTS） and other electrical measurement techniques, localized deep levels in n-type AlxGal xN epitaxial films with various A1 compositions （x = 0, 0.14...By using high-temperature deep-level transient spectroscopy （HT-DLTS） and other electrical measurement techniques, localized deep levels in n-type AlxGal xN epitaxial films with various A1 compositions （x = 0, 0.14, 0.24, 0.33, and 0.43） have been investigated. It is found that there are three distinct deep levels in AlxGal-xN films, whose level position with respect to the conduction band increases as AI composition increases. The dominant defect level with the activation energy deeper than 1.0 eV below the conduction band closely follows the Fermi level stabilization energy, indicating that its origin may be related to the defect complex, including the anti-site defects and divacancies in AlxGa1-xN films.展开更多
We study the stability of vortices pinning and dynamics in a superconducting thin strip containing a square array of antidot triplets by using the nonlinear Ginzburg–Landau(GL)theory.Compared with the regular square ...We study the stability of vortices pinning and dynamics in a superconducting thin strip containing a square array of antidot triplets by using the nonlinear Ginzburg–Landau(GL)theory.Compared with the regular square array of circular holes,the vortices are no longer pinned inside the circular holes,but instead stabilized at the center of the antidot triplets depending on the geometry parameters.Moreover,the influences of the geometry parameters and the polarity of the applied current on the current–voltage(I–V)characteristics are also studied.The critical current for the sample turning into a normal state becomes smaller when the hole diameter D is smaller and the spacing B between the holes is larger.Due to the asymmetric pinning sites,our numerical simulations demonstrate that the positive and negative rectified voltages appear alternately in the resistive state of the sample under an ac current of square pulses.展开更多
In this paper,a computer-controlled photovoltaic(PV)array simulator consisted of a synchronous buck DC converter and its associate control software is proposed and developed to simulate the current-voltage(I-V)output ...In this paper,a computer-controlled photovoltaic(PV)array simulator consisted of a synchronous buck DC converter and its associate control software is proposed and developed to simulate the current-voltage(I-V)output characteristics of a real-time PV array with actual loads connected.The main advantage of this simulator is its ability in simulating different types and sizes of arrays under various illumination and temperature conditions.It can replace the actual PV array and perform all the simulations indoor instead of outside field testing.The mathematical model implemented in this system requires minimum manufacturer's data.This system is a very cost effective and reliable laboratory tool to investigate the output characteristics of PV array under various weather conditions,and is helpful for developing new maximum power point tracking(MPPT)algorithms.展开更多
We have studied the forward I-V characteristics of In-pWSe2Schottky barrier diode with 1000 ? indium thickness in the temperature range 140 – 300 K well within the domain of thermionic emission theory with Gaussian d...We have studied the forward I-V characteristics of In-pWSe2Schottky barrier diode with 1000 ? indium thickness in the temperature range 140 – 300 K well within the domain of thermionic emission theory with Gaussian distribution of barrier height. However we found some anomalies in the low temperature range below 200 K. Hence we have considered a model that incorporates thermionic emission, generation recombination and tunneling components. The low temperature anomalies observed in the diode parameters were effectively construed in terms of the contribution of these multiple charge transport mechanisms across the interface of the fabricated diodes. Various Schottky diode parameters were also extracted and compared with that of 500 ? metal thickness In-pWSe2 diode.展开更多
We report a facile method for the fabrication of TiO2 nanofiber-nanoparticle composite （FP） via. simulta- neous electrospraying and electrospinning for dye-sensitized solar cell （DSC） applications. The loading of ...We report a facile method for the fabrication of TiO2 nanofiber-nanoparticle composite （FP） via. simulta- neous electrospraying and electrospinning for dye-sensitized solar cell （DSC） applications. The loading of nanoparticles on the fibers is controlled by varying their feed rates during electrospinning. The FP composites having three different particle loading are prepared by the methodology and the FP with the highest particle loading （denoted as FP-3 in the manuscript） showed the best overall efficiency of 9.15% in comparison to the other compositions of the FP （FP-2, 8.15% and FP-1, Z51%, respectively） and nanofibers （F） and nanoparticles （P） separately （7.21 and 7.81, respectively）. All the material systems are characterized by spec- troscopy, microscopy, surface area measurements and the devices are characterized by current-voltage （I-V）, incident photon-to-current conversion efficiency （IPCE）, electrochemical impedance measurements, etc. I-V, dye-loading and reflectance measurements throw light on the overall performance of the DSC devices.展开更多
Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking...Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking the biological nanopore in living cells. Understanding the transport mechanism of biological nanopore in vivo is a big challenge because of the experimental difficulty, so it is essential to establish the basic research of artificial nanopores in vitro especially for the analysis of ions and small molecules. The performance of solid-state nanopores could be evaluated by monitoring currents when ions and molecules passed through. The comparison of the two types of nanopores based on current-derived information can reveal the principle of biological nanopores, while the solid-state nanopores are applied into practical bioanalysis. In this review, we focus on the researches of the solid-state nanopores in the fabrication process and in the analysis of ions and small molecules. Fabrication methods of nanopores,ion transport mechanism, small molecule analysis and theoretical studies are discussed in detail.展开更多
In this paper, we study the effects of an unintended dopant in the channel on the current-voltage char-acteristics of a Double-Gate (DG) Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). Non-Equilibrium Gree...In this paper, we study the effects of an unintended dopant in the channel on the current-voltage char-acteristics of a Double-Gate (DG) Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). Non-Equilibrium Green's Function (NEGF) approach is used. A quantum transport model to calculate the drain current is presented and subthreshold swing and drain induced barrier lowering (DIBL) effect are studied.展开更多
基金supported by the Russian Foundation for Basic Research(RFBR),project number 19–38-90116。
文摘Objective:This study aimed to develop expert fuzzy logic model to assist physicians in the prediction of postoperative complications of prostatic hyperplasia before surgery.Methods:A method for classification of surgical risks was developed.The effect of rotation of the current–voltage characteristics at biologically active points(acupuncture points)was used for the formation of classifier descriptors.The effect determined reversible and non-reversible changes in electrical resistance at acupuncture points with periodic exposure to a sawtooth probe current.Then,the developed method was tested on the prediction of the success of surgical treatment of benign prostatic hyperplasia.Results:Input descriptors were obtained from collected data including current-voltage characteristics of 5 acupuncture points and composed of 27 arrays feeding in the model.The maximum diagnostic sensitivity of the classifier for the success of a surgical operation in the control sample was 88%and for testing data set prediction accuracy was 97%.Conclusion:The use of tuples of current-voltage characteristic descriptors of acupuncture points in the classifiers could be used to predict the success of surgical treatment with satisfactory accuracy.The model can be a valuable tool to support physicians’diagnosis.
基金supported by the National Natural Science Foundation of China (10975103)
文摘Polycrystalline La0.67Ba0.33MnO3 bulk samples were annealed in flowing 95%Ar：5%H2 （AH） mixed gas at 973 K for different time respectively. The influence of the annealing time on the current-voltage properties was systematically investigated. Linear current-voltage characteristics were observed in the as-prepared and the 10 h annealed samples, and nonlinear current-voltage characteristics was found in the 100 h annealed sample. At the same time, segregation of impurity phase and micro-cracks were found on the surfaces of the 100 h annealed samples, which was testified to be Ba ion impurity. Analysis showed that the changes of electronic properties were caused by barium ion im-purities and micro-cracks in the 100 h annealed sample.
基金financially supported by the National Science Fund for Distinguished Young Scholars (No. 50925311)National Science Fund of China (Nos. 20976112, 51033004)
文摘Current-voltage electrical behavior of in situ microfibrillar carbon black （CB）/poly（ethylene terephthalate） （PET）/polyethylene （PE） （m-CB/PET/PE） composites with various CB concentrations at ambient temperatures was studied under a direct-current electric field. The current-voltage （l-V） curves exhibited nonlinearity beyond a critical value of voltage. The dynamic random resistor network （DRRN） model was adopted to semi-qualitatively explain the nonlinear conduction behavior of m-CB/PET/PE composites. Macroscopic nonlinearity originated from the interfacial interactions between CB/PET micro fibrils and additional conduction channels. Combined with the special conductive networks, an illustration was proposed to interpret the nonlinear 1-V characteristics by a field emission or tunneling mechanism between CB particles in the CB/PET micro fibers intersections.
基金the Ministry of Science and Higher Education of the Russian Federation under Grant No.FSUN-2023-0007.
文摘Some electrical parameters of the SIS-type hysteretic underdamped Josephson junction(JJ)can be measured by its current-voltage characteristics(IVCs).Currents and voltages at JJ are commensurate with the intrinsic noise level of measuring instruments.This leads to the need for multiple measurements with subsequent statistical processing.In this paper,the digital algorithms are proposed for the automatic measurement of the JJ parameters by IVC.These algorithms make it possible to implement multiple measurements and check these JJ parameters in an automatic mode with the required accuracy.The complete sufficient statistics are used to minimize the root-mean-square error of parameter measurement.A sequence of current pulses with slow rising and falling edges is used to drive JJ,and synchronous current and voltage readings at JJ are used to realize measurement algorithms.The algorithm performance is estimated through computer simulations.The significant advantage of the proposed algorithms is the independence from current source noise and intrinsic noise of current and voltage meters,as well as the simple implementation in automatic digital measuring systems.The proposed algorithms can be used to control JJ parameters during mass production of superconducting integrated circuits,which will improve the production efficiency and product quality.
文摘It is shown that the nonideality coefficient m actually depends on the electron temperature Te, and the hole temperature Th. We get more general expression for the nonideality coefficient, taking into account the concentration of electrons and holes, as well as their temperature, coefficient and diffusion length, the temperature of the phonons, the applied voltage, and the height of the potential barrier.
基金Project supported by the National Natural Science Foundation of China(No.61006053)the National Science Foundation ofCQ CSTC (No.CSTC 2008BB3156)
文摘The factors influencing the current-voltage（I-V） characteristics of light-emitting diodes（LEDs） are investigated to reveal the connection of I-V characteristics under optical excitation and those under electrical excitation.By inspecting the I-V curves under optical and electrical excitation at identical injection current,it has been found that the I-V curves exhibit apparent differences in voltage values.Furthermore,the differences are found to originate from the junction temperatures in diverse excitation ways.Experimental results indicate that if the thermal effect of illuminating spot is depressed to an ignorable extent by using pulsed light,the junction temperature will hardly deflect from that under optical excitation,and then the I-V characteristics under two diverse excitation ways will be the same.
文摘A high performance AlAs/In0.53 Ga0.47 As/InAs resonant tunneling diode （RTD） on InP substrate is fabricated by inductively coupled plasma etching. This RTD has a peak-to-valley current ratio （PVCR） of 7. 57 and a peak current density Jp = 39.08kA/cm^2 under forward bias at room temperature. Under reverse bias, the corresponding values are 7.93 and 34.56kA/cm^2 . A resistive cutoff frequency of 18.75GHz is obtained with the effect of a parasitic probe pad and wire. The slightly asymmetrical current-voltage characteristics with a nominally symmetrical structure are also discussed.
基金Project supported by the National Natural Science Foundation of China (Nos.11972164,11672113,11472182)the Key Laboratory Project of Hubei Province of China (No.2016CFA073)。
文摘A full-coupling model on the current-voltage(J-V)characteristics of PN junctions is put forward in the paper by taking into account both the whole junction and the two electrode regions consisting of metal/semiconductor(M/S)contacts.The depletion layer assumption proposed by the Shockley model is discarded.Gauss’law on the electric potential and the electric field is applied in the whole junction region such that the majority-carrier currents inside and outside the P/N barrier region are able to be exactly defined and clearly calculated.Then,the stable continuity equations of the electron and hole currents are established to show the current conversion between minority-and majority-carriers inside the whole PN junction region.By analyzing all the conversion procedure,the J-V characteristics of a PN junction are obtained with good agreement to the experimental results,which are closely dependent on the minority-carrier lifetime and doping concentrations.Obviously,the study on this topic possesses referential significance to mechanically tuning the performance of piezoelectric PN junctions and piezotronic devices.
基金financially supported by the Programs for New Century Excellent Talents in University(NCETNo.06-0303)the National Natural Science Foundation of China(NSFC,No.50772041)
文摘Nitrogen-doped nanocrystalline diamond films(N-NDFs)have been deposited on p-type silicon(Si)by microwave plasma chemical vapor deposition.The reaction gases are methane,hydrogen,and nitrogen without the conventional argon(Ar).The N-NDFs were characterized by X-ray diffraction,Raman spectroscopy,and scanning electron microscopy.The grain sizes are of 8~10 nm in dimension.The N-NDF shows n-type behavior and the corresponding N-NDF/p-Si heterojunction diodes are realized with a high rectification ratio of 102 at^7.8 V,and the current density reaches to1.35 A/cm2 at forward voltage of 8.5 V.The findings suggest that fabricated by CH_4/H_2/N_2 without Ar,the N-NDFs and the related rectifying diodes are favorable for achieving high performance diamond-based optoelectronic devices.
基金supported by the National Natural Science Foundation of China (41404058)Beijing Natural Science Foundation (8184091)
文摘The Langmuir Probe(LAP), onboard the China Seismo-Electromagnetic Satellite(CSES), has been designed for in situ measurements of bulk parameters of the ionosphere plasma, the first Chinese application of in-situ measurement technology in the field of space exploration. The two main parameters measured by LAP are electron density and temperature. In this paper, a brief description of the LAP and its work mode are provided. Based on characteristics of the LAP, and assuming an ideal plasma environment, we introduce in detail a method used to invert the I-V curve; the data products that can be accessed by users are shown. Based on the LAP data available, this paper reports that events such as earthquakes and magnetic storms are preceded and followed by obvious abnormal changes. We suggest that LAP could provide a valuable data set for studies of space weather, seismic events, and the ionospheric environment.
基金Project supported by University Malaya and Ministry of Higher Education Malaysia under grant(KPT 1059-2012)Science Fund(SF019-2013)Fundamental Research Grant Scheme(FP033-2013B)
文摘Terbium-picrate triethylene glycol（EO3-Tb-Pic） complex was prepared in thin film and single layer device structure of ITO/EO3-Tb-Pic/Al, using spin coating technique. The UV-Vis absorption spectroscopy analysis was performed to evaluate the electronic molecular transition of the complex. The optical band gap, Eg estimated from the Tauc model revealed that EO3-Tb-Pic thin film exhibited a direct transition with Eg of 2.70 eV. The electronic parameters of the ITO/EO3-Tb-Pic/Al device such as the ideality factor n, barrier height Φb, saturation current Io, and series resistance Rs, were extracted from the conventional lnI-V, Cheung＇s functions and Norde＇s method. It was found that the evaluated parameters calculated from Norde＇s and Cheung＇s methods were consistent with those calculated from the conventional I-V method. In the double logarithmic I-V plot, three distinct regions based on the slope were identified, and the conduction mechanisms were discussed and explained. The mobility, μ value was estimated from SCLC region as 2.58×10^–7 cm2/（V·s）. This newly obtained lanthanide complex may be potentially utilized in electronic devices.
基金Supported by the National Natural Science Foundation of China (No. 29976040), the Natural Science Foundation of Anhui Province (No. 99045431) and Youth Foundation of USTC.
文摘This work is concentrated on elucidating the mechanism of the electric field enhanced water dissociation. A simple model was established for the theoretical current-voltage characteristics in water dissociation process on a bipolar membrane based on the existence of a depletion layer and Onsager's theory. Particular attention was given to the influence of applied voltage on depletion thickness and the dissociation constant. The factors on the water splitting process, such as water diffusivity, water content, ion exchange capacity, temperature, relative permittivity, etc. Were adequately analysed based on the derived model equations and several suggestions were proposed for decreasing the applied voltage in practical operation. The water dissociation tests were conducted and compared with both the theoretical calculation and the measured current-voltage curves reported in the literature, which showed a very good prediction to practical current-voltage behavior of a bipolar membrane at high current densities when the splitting of water actually commenced.
基金This work was supported by the National Basic Research Program of China （No.2012CB215405）, the National Natural Science Foundation of China （No.11374272）, and the Specialized Research Fund for the Doctoral Program of Higher Education （No.20123402110064）.
文摘Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick＇s model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.
基金supported by the National Basic Research Program of China(Grant No.2012CB619300)the National Natural Science Foundation of China(Grant Nos.11174008 and 61361166007)
文摘By using high-temperature deep-level transient spectroscopy （HT-DLTS） and other electrical measurement techniques, localized deep levels in n-type AlxGal xN epitaxial films with various A1 compositions （x = 0, 0.14, 0.24, 0.33, and 0.43） have been investigated. It is found that there are three distinct deep levels in AlxGal-xN films, whose level position with respect to the conduction band increases as AI composition increases. The dominant defect level with the activation energy deeper than 1.0 eV below the conduction band closely follows the Fermi level stabilization energy, indicating that its origin may be related to the defect complex, including the anti-site defects and divacancies in AlxGa1-xN films.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11702034,11702218,and 11421062)Fundamental Research Funds for the Central Universities,China(Grant Nos.310812171011 and G2016KY0305)the National Key Project of Magneto-Constrained Fusion Energy Development Program,China(Grant No.2013GB110002)
文摘We study the stability of vortices pinning and dynamics in a superconducting thin strip containing a square array of antidot triplets by using the nonlinear Ginzburg–Landau(GL)theory.Compared with the regular square array of circular holes,the vortices are no longer pinned inside the circular holes,but instead stabilized at the center of the antidot triplets depending on the geometry parameters.Moreover,the influences of the geometry parameters and the polarity of the applied current on the current–voltage(I–V)characteristics are also studied.The critical current for the sample turning into a normal state becomes smaller when the hole diameter D is smaller and the spacing B between the holes is larger.Due to the asymmetric pinning sites,our numerical simulations demonstrate that the positive and negative rectified voltages appear alternately in the resistive state of the sample under an ac current of square pulses.
文摘In this paper,a computer-controlled photovoltaic(PV)array simulator consisted of a synchronous buck DC converter and its associate control software is proposed and developed to simulate the current-voltage(I-V)output characteristics of a real-time PV array with actual loads connected.The main advantage of this simulator is its ability in simulating different types and sizes of arrays under various illumination and temperature conditions.It can replace the actual PV array and perform all the simulations indoor instead of outside field testing.The mathematical model implemented in this system requires minimum manufacturer's data.This system is a very cost effective and reliable laboratory tool to investigate the output characteristics of PV array under various weather conditions,and is helpful for developing new maximum power point tracking(MPPT)algorithms.
文摘We have studied the forward I-V characteristics of In-pWSe2Schottky barrier diode with 1000 ? indium thickness in the temperature range 140 – 300 K well within the domain of thermionic emission theory with Gaussian distribution of barrier height. However we found some anomalies in the low temperature range below 200 K. Hence we have considered a model that incorporates thermionic emission, generation recombination and tunneling components. The low temperature anomalies observed in the diode parameters were effectively construed in terms of the contribution of these multiple charge transport mechanisms across the interface of the fabricated diodes. Various Schottky diode parameters were also extracted and compared with that of 500 ? metal thickness In-pWSe2 diode.
基金supported by Ministry of New and Renewable Energy(MNRE)the Solar Energy Research Initiative(SERI),respectively.of Govt.of India
文摘We report a facile method for the fabrication of TiO2 nanofiber-nanoparticle composite （FP） via. simulta- neous electrospraying and electrospinning for dye-sensitized solar cell （DSC） applications. The loading of nanoparticles on the fibers is controlled by varying their feed rates during electrospinning. The FP composites having three different particle loading are prepared by the methodology and the FP with the highest particle loading （denoted as FP-3 in the manuscript） showed the best overall efficiency of 9.15% in comparison to the other compositions of the FP （FP-2, 8.15% and FP-1, Z51%, respectively） and nanofibers （F） and nanoparticles （P） separately （7.21 and 7.81, respectively）. All the material systems are characterized by spec- troscopy, microscopy, surface area measurements and the devices are characterized by current-voltage （I-V）, incident photon-to-current conversion efficiency （IPCE）, electrochemical impedance measurements, etc. I-V, dye-loading and reflectance measurements throw light on the overall performance of the DSC devices.
基金financially supported by the National Natural Science Foundation of China (No. 21505076)the Young Elite Scholar Support (YESS) Program from China Association for Science and Technology (No. YESS20150009)+2 种基金the Program of Jiangsu Specially-Appointed Professor, the Natural Science Foundation of Jiangsu Province of China (No. BK20150967)the Innovation Team Program of Jiangsu Province of Chinathe Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Solid-state nanopore in analytical chemistry has developed rapidly in the 1990s and it is proved to be a versatile new tool for bioanalytical chemistry. The research field of solid-state nanopore starts from mimicking the biological nanopore in living cells. Understanding the transport mechanism of biological nanopore in vivo is a big challenge because of the experimental difficulty, so it is essential to establish the basic research of artificial nanopores in vitro especially for the analysis of ions and small molecules. The performance of solid-state nanopores could be evaluated by monitoring currents when ions and molecules passed through. The comparison of the two types of nanopores based on current-derived information can reveal the principle of biological nanopores, while the solid-state nanopores are applied into practical bioanalysis. In this review, we focus on the researches of the solid-state nanopores in the fabrication process and in the analysis of ions and small molecules. Fabrication methods of nanopores,ion transport mechanism, small molecule analysis and theoretical studies are discussed in detail.
基金Supported of National Natural Science Foundation of China under Grant Nos. 61171010 and 61171011the State Key Laboratory of ASIC and System is Appreciated under Grant No. 11MS015the Special Funds for Major State Basic Research (973) under Grant No. 2011CBA00603
文摘In this paper, we study the effects of an unintended dopant in the channel on the current-voltage char-acteristics of a Double-Gate (DG) Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). Non-Equilibrium Green's Function (NEGF) approach is used. A quantum transport model to calculate the drain current is presented and subthreshold swing and drain induced barrier lowering (DIBL) effect are studied.
