Parvalbumin-positive(PV^(+))interneuron dysfunction is believed to be linked to autism spectrum disorder(ASD),a neurodevelopmental disorder characterized by social deficits and stereotypical behaviors.However,the mech...Parvalbumin-positive(PV^(+))interneuron dysfunction is believed to be linked to autism spectrum disorder(ASD),a neurodevelopmental disorder characterized by social deficits and stereotypical behaviors.However,the mechanisms behind PV^(+)interneuron dysfunction remain largely unclear.Here,we found that a deficiency of Biorientation Defective 1(Bod1)in PV^(+)interneurons led to an ASD-like phenotype in Pvalb-Cre;Bod1f/f mice.Mechanistically,we observed that Bod1 deficiency induced hypoactivity of PV^(+)interneurons and hyperactivity of calcium/calmodulin-dependent protein kinaseⅡalpha(CaMKⅡα)neurons in the medial prefrontal cortex,as determined by whole-cell patch-clamp recording.Additionally,Bod1 deficiency decreased the power of highgamma oscillation,assessed by in vivo multi-channel electrophysiological recording.Furthermore,we found that Bod1 deficiency enhanced the inwardly rectifying K^(+)current,leading to an increase in the resting membrane potential of PV^(+)interneurons.Importantly,the gain-of-function of Bod1 improved social deficits and stereotypical behaviors in Pvalb-Cre;Bod1f/f mice.These findings provide mechanistic insights into the PV^(+)interneuron dysfunction and suggest new strategies for developing PV^(+)interneuron-targeted therapies for ASD.展开更多
The anchoring eccentricity of the bolt and cable bolt is a common problem in geotechnical support engineering and affects the ability of the bolt and cable bolt to control the rock mass to a certain extent.This paper ...The anchoring eccentricity of the bolt and cable bolt is a common problem in geotechnical support engineering and affects the ability of the bolt and cable bolt to control the rock mass to a certain extent.This paper reports on numerical simulation and laboratory experiments conducted to clarify the effect of eccentricity on the anchoring quality of the bolt and cable bolt,and to establish an effective solution strategy.The results reveal that the anchoring eccentricity causes unbalanced stress distribution and the uncoordinated deformation of the resin layer,which results in higher stress and greater deformation of the resin layer at the near side of the rod body.Additionally,as the degree of anchoring eccentricity increases,the effect becomes more significant,and the resin layer of the anchoring system becomes more likely to undergo preferential failure locally,which weakens the load-bearing performance of the anchoring system.This paper develops an innovative bolt anchoring rectifying device(B-ARD)and cable bolt anchoring rectifying device(C-ARD)on the basis of the structural characteristics of the bolt and cable bolt to better ensure the anchoring effect of them.The working effects of these two devices were verified in detailed experiments and analysis.The experimental results show that the anchoring rectifying devices(ARD)improve and ensure the anchoring concentricity of the bolt and cable bolt,which will help improve the supporting performance of them.The paper provides a convenient and effective method for improving the anchoring concentricity of the bolt and cable bolt,and provides a concept and reference for technical research on improving the effect of roof bolting.展开更多
With the growing needs of prepreg tapes for the automated fiber placement(AFP),the deviation-rectifying of prepreg in slitting process was investigated on a self-developed 16-tow prepreg slitting and winding machine.T...With the growing needs of prepreg tapes for the automated fiber placement(AFP),the deviation-rectifying of prepreg in slitting process was investigated on a self-developed 16-tow prepreg slitting and winding machine.The process of slitting and rewinding of prepreg tape was introduced,and the reason of prepreg tape deviation in slitting process was analyzed.In order to ensure the quality of the narrow prepreg slits,the application of the fuzzy PID algorithm in a closed-loop control system was discussed.A fuzzy PID algorithm was designed by combining fuzzy rules and PID controller.By applying it to precise deviation-rectifying control strategy,the automatic control of rectification could be achieved with accuracy of 0.1 mm,which satisfies the requirement of the prepreg tape both in slitting quality and layup quality for AFP.展开更多
Rational design and construction of oxygen reduction reaction(ORR)electrocatalysts with high activity,good stability,and low price are essential for the practical applications of renewable energy conversion devices,su...Rational design and construction of oxygen reduction reaction(ORR)electrocatalysts with high activity,good stability,and low price are essential for the practical applications of renewable energy conversion devices,such as metal-air batteries.Electronic modification through constructing metal/semiconductor Schottky heterointerface represents a powerful strategy to enhance the electrochemical performance.Herein,we demonstrate a concept of Schottky electrocatalyst composed of uniform Co nanoparticles in situ anchored on the carbon nanotubes aligned on the carbon nanosheets(denoted as Co@N-CNTs/NSs hereafter)toward ORR.Both experimental findings and theoretical simulation testify that the rectifying contact could impel the voluntary electron flow from Co to N-CNTs/NSs and create an internal electric field,thereby boosting the electron transfer rate and improving the intrinsic activity.As a consequence,the Co@N-CNTs/NSs deliver outstanding ORR activity,impressive long-term durability,excellent methanol tolerance,and good performance as the air-cathode in the Zn-air batteries.The design concept of Schottky contact may provide the innovational inspirations for the synthesis of advanced catalysts in sustainable energy conversion fields.展开更多
Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell, were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of the preparation...Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell, were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of the preparation conditions of PANI and PS, the electronic structure of PANI as well as cell structure. The rectifying parameters of Al/PS-PANI/Au cell were determined to be gamma = 1.8x10(1) similar to 1.0x10(5) for the rectifying ratio at 3V, n = 3 similar to 12 for the ideal factor, j(0) = 8.0x10(-5) similar to 5.6x10(-2) mA/cm(2) for the reversed saturated current density, and phi(0) = 0.67 similar to 0.83 V for the barrier height, respectively. The best rectifying heterojunction diode made between PANI and n-type PS with higher rectifying factor (gamma = 1.0x10(5) at 3V), output current (>1500 mA/cm(2) at 3V) and lower ideal factor (n = 3.3) was obtained by preventing the oxidation of PS before evaporating Al electrode.展开更多
In wind power system,the randomness of wind energy increases the probability of components fault.once the switch fault of the PWM rectifier is detected,it will lead to the distortion of the motor voltage and current w...In wind power system,the randomness of wind energy increases the probability of components fault.once the switch fault of the PWM rectifier is detected,it will lead to the distortion of the motor voltage and current waveform,the increase of torque ripple,the fluctuation of filter capacitor voltage,and the increase of harmonic content,which will affect the control performance and operation safety of the system.A common fault in a three-phase PWM rectifier is the open-circuit fault of the switch.This paper analyzes the current waveform distortion of the square wave motor when the rectifier switch fault,and proposes different fault-tolerant control strategies for different situations of switch fault,include single,double and triple switches fault.This method is based on several special driving modes under power generation situation of square wave motor.The strategy is easy to implement and does not need to change the circuit topology.It can realize fault-tolerant control of switch faults in the same side half bridge or the same bridge arm of the three-phase PWM rectifier.The effectiveness of the proposed fault-tolerant strategy is verified by simulation and experiment at the end of the article.展开更多
The diode rectifier unit(DRU)-based high-voltage DC(DRU-HVDC) system is a promising solution for offshore wind energy transmission thanks to its compact design, high efficiency, and strong reliability. Herein we inves...The diode rectifier unit(DRU)-based high-voltage DC(DRU-HVDC) system is a promising solution for offshore wind energy transmission thanks to its compact design, high efficiency, and strong reliability. Herein we investigate the feasibility of the DRU-HVDC system considering onshore and offshore AC grid faults, DC cable faults, and internal DRU faults. To ensure safe operation during the faults, the wind turbine(WT) converters are designed to operate in either current-limiting or voltage-limiting mode to limit potential excessive overcurrent or overvoltage. Strategies for providing fault currents using WT converters during offshore AC faults to enable offshore overcurrent and differential fault protection are investigated. The DRU-HVDC system is robust against various faults, and it can automatically restore power transmission after fault isolation. Simulation results confirm the system performance under various fault conditions.展开更多
This paper presents an RF energy harvesting system for wireless intraocular pressure monitoring applications.The system consists of an implantable antenna and a rectifier.A new sizing strategy is adopted to optimize t...This paper presents an RF energy harvesting system for wireless intraocular pressure monitoring applications.The system consists of an implantable antenna and a rectifier.A new sizing strategy is adopted to optimize the conversion efficiency of the rectifier,and the design principle of an implantable antenna is introduced from material selection and structure design.Results from testing demonstrate that the antenna gain is about-20 dBi and the rectifier's maximum total conversion efficiency which contains match efficiency and rectifying efficiency is 47.18%under the implementation of0.18μm standard CMOS process.The maximum power obtained from the proposed system is 8μW when the power density of electromagnetic wave is lower than the national standard 40μW/cm^2 at915 MHz,which is enough to power the intraocular pressure monitoring system.展开更多
Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to Ga...Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This “rectifying” effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit （VEPF） analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.展开更多
An innovative heterojunction is fabricated between two sides of a freestanding thin film of HCl-doped polyaniline （PANI） derivative containing azobenzene side-chain, which is synthesized through an N-alkyl-substitut...An innovative heterojunction is fabricated between two sides of a freestanding thin film of HCl-doped polyaniline （PANI） derivative containing azobenzene side-chain, which is synthesized through an N-alkyl-substituted reaction. of the film, the side with being irradiated by UV light during preparation is represented as ＇A side＇; the other side without being irradiated is represented as ＇N side＇. The electrical properties of the heterojunction are measured and the rectifying effect is observed in the current voltage characteristic curves with the values of rectifying ratio （30 being 20 at ±0.06 V at T = 77 K and 4 at ±0.02 V at T = 300 K separately.展开更多
ZnCo2O4/Si heterostructures have been fabricated by a pulsed laser deposition method, and their transport behaviors and photovoltaic properties have been characterized. The ZnCo2O4/Si heterostructures show a good rect...ZnCo2O4/Si heterostructures have been fabricated by a pulsed laser deposition method, and their transport behaviors and photovoltaic properties have been characterized. The ZnCo2O4/Si heterostructures show a good rectifying behavior at five different temperatures ranging from 50 K to 290 K. The measurements of the photovoltaic response reveals that a photovoltage of 33 mV is generated when the heterostructures are illuminated by a 532 nm laser of 250 mW/cm^2 and mechanically chopped at 2500 Hz. Both the photocurrent and the photovoltage clearly increase with the increase of the laser intensity at room temperature. However, the heterostructures＇ photovoltage peak decreases with the increase of the temperature. This work may open new perspectives for ZnCo2O4/Si heterostructure-based devices.展开更多
This paper reports that the Schottky junctions between low work function metals （e.g. Al and In） and doped semiconducting polymer pellets （e.g. polyaniline （PANI） microsphere pellet and polypyrrole （PPy） nanotu...This paper reports that the Schottky junctions between low work function metals （e.g. Al and In） and doped semiconducting polymer pellets （e.g. polyaniline （PANI） microsphere pellet and polypyrrole （PPy） nanotube pellet） have been prepared and studied. Since Ag is a high work function metal which can make an ohmic contact with polymer, silver paste was used to fabricate the electrodes. The Al/PANI/Ag heterojunction shows an obvious rectifying effect as shown in I - V characteristic curves （rectifying ratio γ = 5 at ±6 V bias at room temperature）. As compared to the Al/PANI/Ag, the heterojunction between In and PANI （In/PANI/Ag） exhibits a lower rectifying ratio γ= 1.6 at ±2 V bias at room temperature. In addition, rectifying effect was also observed in the heterojunctions Al/PPy/Ag （γ = 3.2 at ±1.6 V bias） and In/PPy/Ag （γ = 1.2 at ±3.0 V bias）. The results were discussed in terms of thermoionic emission theory.展开更多
The group of peasant laborer, being a beneficial group in present Chinese society, has already come into being, which is both outcome of duality and the important strength breaking duality in Chinese society. However,...The group of peasant laborer, being a beneficial group in present Chinese society, has already come into being, which is both outcome of duality and the important strength breaking duality in Chinese society. However, for a long time the severe maladjustments of peasant laborer group＇s not only engender the injustice of their position but also do harm to the development of social structure and economic growth in China. Therefore, describing the position of peasant laborer group and analyzing the consequence which causes by their imbalance position may have significant impact on perfecting Chinese social structure and attaining the objectives of combining the city with countryside in theory and practice.展开更多
A Bi2Sr2Co2Oy/Si heterojunction is obtained by growing a layer of p-type oxygen-deficient Bi2Sr2Co2Oy film on a commercial n-type silicon wafer by pulsed laser deposition. Its rectifying and photovoltaic properties ar...A Bi2Sr2Co2Oy/Si heterojunction is obtained by growing a layer of p-type oxygen-deficient Bi2Sr2Co2Oy film on a commercial n-type silicon wafer by pulsed laser deposition. Its rectifying and photovoltaic properties are studied in a wide temperature range from 20 K to 300 K. The transport mechanism under the forward bias can be attributed to a trap- filled space-charge-limited current conduction mechanism. Under the irradiation of a 532-nm continuous wave laser, a clear photovoltaic effect is observed and the magnitude ofphotovoltage increases as the temperature decreases, The results demonstrate the potential application of a Bi2SrzCo2Oy-based heterojunction in the photoelectronic devices.展开更多
This paper explains step-by-step modeling and simulation of the full circuits of a battery control system and connected together starting from the AC input source to the battery control and storage system.The three-ph...This paper explains step-by-step modeling and simulation of the full circuits of a battery control system and connected together starting from the AC input source to the battery control and storage system.The three-phase half-controlled rectifier has been designed to control and convert the AC power into DC power.In addition,two types of direct current converters have been used in this paper which are a buck and bidirectional DC/DC converters.These systems adjust the output voltage to be lower or higher than the input voltage.In the buck converters,the main switch operates in conduction or cut-off mode and is triggered by a Pulse-Width Modulated(PWM)signal.The output and input voltage levels ratio are used to calculate thePWMsignal’s duty cycle.Therefore,the duty cycle indicates the operation mode of the converter in steady-state operation.In this study,we analyze and control of a buck converter with the PWM signal.Besides,the bidirectional DC/DC converter has been achieved and optimized by PI control methods to control the battery charging and discharging modes.The simulation has been applied via the Matlab/Simulink environment.The results show the activity of each part of the designed circuits starting from the converters and the battery control system in charge and discharge modes.展开更多
In view of the complexity and uncertainty of system, both the state performances and state probabilities of multi-state components can be expressed by interval numbers. The belief function theory is used to characteri...In view of the complexity and uncertainty of system, both the state performances and state probabilities of multi-state components can be expressed by interval numbers. The belief function theory is used to characterize the uncertainty caused by various factors. A modified Markov model is proposed to obtain the state probabilities of components at any given moment and subsequently the mass function is used to represent the precise belief degree of state probabilities. Based on the primary studies of universal generating function(UGF)method, a belief UGF(BUGF) method is utilized to analyze the reliability and the uncertainty of excavator rectifier feedback system. This paper provides an available method to evaluate the reliability of multi-state systems(MSSs) with interval state performances and state probabilities, and also avoid the interval expansion problem.展开更多
Security systems are the need of the hour to protect data from unauthorized access.The dissemination of confidential information over the public network requires a high level of security.The security approach such as ...Security systems are the need of the hour to protect data from unauthorized access.The dissemination of confidential information over the public network requires a high level of security.The security approach such as steganography ensures confidentiality,authentication,integrity,and non-repudiation.Steganography helps in hiding the secret data inside the cover media so that the attacker can be confused during the transmission process of secret data between sender and receiver.Therefore,we present an efficient hybrid security model that provides multifold security assurance.To this end,a rectified Advanced Encryption Standard(AES)algorithm is proposed to overcome the problems existing in AES such as pattern appearance and high computations.The modified AES is used for the encryption of the stego image that contains the digitally signed encrypted secret data.The enciphering and deciphering of the secret data are done using the Rivest–Shamir–Adleman(RSA)algorithm.The experiments are conducted on the images of the USC-SIPI standard image database.The experimental results prove that the proposed hybrid system outperforms other SOTA(state-of-the-art)approaches.展开更多
The acceleration grid power supply(AGPS) is a crucial part of the Negative-ion Neutral Beam Injection system in the China Fusion Engineering Test Reactor,which includes a 3-phase passive(diode) rectifier.To diagnose a...The acceleration grid power supply(AGPS) is a crucial part of the Negative-ion Neutral Beam Injection system in the China Fusion Engineering Test Reactor,which includes a 3-phase passive(diode) rectifier.To diagnose and localize faults in the rectifier,this paper proposes a frequencydomain analysis-based fault diagnosis algorithm for the rectifier in AGPS.First,time-domain expressions and spectral characteristics of the output voltage of the TPTL-NPC inverter-based power supply are analyzed.Then,frequency-domain analysis-based fault diagnosis and frequency-domain analysis-based sub-fault diagnosis algorithms are proposed to diagnose open circuit(OC) faults of diode(s),which benefit from the analysis of harmonics magnitude and phase-angle of the output voltage.Only a fundamental period is needed to diagnose and localize exact faults,and a strong Variable-duration Fault Detection Method is proposed to identify acceptable ripple from OC faults.Detailed simulations and experimental results demonstrate the effectiveness,quickness,and robustness of the proposed algorithms,and the diagnosis algorithms proposed in this article provide a significant method for the fault diagnosis of other rectifiers and converters.展开更多
The design of multiband microstrip rectenna for radio frequency energy harvesting applications is presented in this paper. The designed antenna has good performance in the GSM-900/1800, WiFi and WLAN bands. In additio...The design of multiband microstrip rectenna for radio frequency energy harvesting applications is presented in this paper. The designed antenna has good performance in the GSM-900/1800, WiFi and WLAN bands. In addition, the rectifier circuit is designed at multi resonant frequencies to collect the largest amount of RF ambient power from different RF sources. The developed antenna is matched with the rectifier at four desired frequencies using several rectifier branches to collect the largest of RF power. The proposed rectenna is printed on FR4 substrate with modified ground plane to achieve suitable impedance bandwidth. The proposed antenna consists of elliptical radiating plane with stubs and stepped modified ground plane. The rectenna resonates at quad frequency bands at (GSM 900/1800, WiFi band and WLAN bands) with rectifier power conversion efficiency up to 56.4% at 0 dBm input power using the HSMS-2850 Schottky diode. The efficiency is more enhanced by using SMS-7630-061 Schottky diode which is characterized by a low junction capacitance and a low threshold voltage to achieve higher conversion efficiency up to 71.1% at the same 0 dBm input power for the same resonating frequency band.展开更多
We report ab initio calculations of the transport behavior of a phenyl substituted molecular motor. The calculated results show that the transport behavior of the device is sensitive to the rotation degree of the roto...We report ab initio calculations of the transport behavior of a phenyl substituted molecular motor. The calculated results show that the transport behavior of the device is sensitive to the rotation degree of the rotor part. When the rotor part is parallel with the stator part, a better rectifying performance can be found in the current-voltage curve. However, when the rotor part revolves to vertical with the stator part, the currents in the positive bias region decrease slightly. More importantly, the rectifying performance disappears. Thus this offers us a new method to modulate the rectifying behavior in molecular devices.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0108600 to Y.M.L.)the National Natural Science Foundations of China(Grant Nos.82473918 and 82104162 to X.X.L.).
文摘Parvalbumin-positive(PV^(+))interneuron dysfunction is believed to be linked to autism spectrum disorder(ASD),a neurodevelopmental disorder characterized by social deficits and stereotypical behaviors.However,the mechanisms behind PV^(+)interneuron dysfunction remain largely unclear.Here,we found that a deficiency of Biorientation Defective 1(Bod1)in PV^(+)interneurons led to an ASD-like phenotype in Pvalb-Cre;Bod1f/f mice.Mechanistically,we observed that Bod1 deficiency induced hypoactivity of PV^(+)interneurons and hyperactivity of calcium/calmodulin-dependent protein kinaseⅡalpha(CaMKⅡα)neurons in the medial prefrontal cortex,as determined by whole-cell patch-clamp recording.Additionally,Bod1 deficiency decreased the power of highgamma oscillation,assessed by in vivo multi-channel electrophysiological recording.Furthermore,we found that Bod1 deficiency enhanced the inwardly rectifying K^(+)current,leading to an increase in the resting membrane potential of PV^(+)interneurons.Importantly,the gain-of-function of Bod1 improved social deficits and stereotypical behaviors in Pvalb-Cre;Bod1f/f mice.These findings provide mechanistic insights into the PV^(+)interneuron dysfunction and suggest new strategies for developing PV^(+)interneuron-targeted therapies for ASD.
基金This study was supported by the National Natural Science Foundation of China(No.52074102)Foundation for Distinguished Young Talents in Higher Education of Henan(No.212300410006)+1 种基金Foundation for the Science and Technology Innovation Talents Project of Universities in Henan(No.22HASTIT010)Special Funds for Fundamental Scientific Research Expenses of Universities in Henan(No.NSFRF210202).
文摘The anchoring eccentricity of the bolt and cable bolt is a common problem in geotechnical support engineering and affects the ability of the bolt and cable bolt to control the rock mass to a certain extent.This paper reports on numerical simulation and laboratory experiments conducted to clarify the effect of eccentricity on the anchoring quality of the bolt and cable bolt,and to establish an effective solution strategy.The results reveal that the anchoring eccentricity causes unbalanced stress distribution and the uncoordinated deformation of the resin layer,which results in higher stress and greater deformation of the resin layer at the near side of the rod body.Additionally,as the degree of anchoring eccentricity increases,the effect becomes more significant,and the resin layer of the anchoring system becomes more likely to undergo preferential failure locally,which weakens the load-bearing performance of the anchoring system.This paper develops an innovative bolt anchoring rectifying device(B-ARD)and cable bolt anchoring rectifying device(C-ARD)on the basis of the structural characteristics of the bolt and cable bolt to better ensure the anchoring effect of them.The working effects of these two devices were verified in detailed experiments and analysis.The experimental results show that the anchoring rectifying devices(ARD)improve and ensure the anchoring concentricity of the bolt and cable bolt,which will help improve the supporting performance of them.The paper provides a convenient and effective method for improving the anchoring concentricity of the bolt and cable bolt,and provides a concept and reference for technical research on improving the effect of roof bolting.
基金financially supported by the National Basic Research Program of China(973Program)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Fundamental Research Funds for the Central Universities ( No. 3082615NS2015056)
文摘With the growing needs of prepreg tapes for the automated fiber placement(AFP),the deviation-rectifying of prepreg in slitting process was investigated on a self-developed 16-tow prepreg slitting and winding machine.The process of slitting and rewinding of prepreg tape was introduced,and the reason of prepreg tape deviation in slitting process was analyzed.In order to ensure the quality of the narrow prepreg slits,the application of the fuzzy PID algorithm in a closed-loop control system was discussed.A fuzzy PID algorithm was designed by combining fuzzy rules and PID controller.By applying it to precise deviation-rectifying control strategy,the automatic control of rectification could be achieved with accuracy of 0.1 mm,which satisfies the requirement of the prepreg tape both in slitting quality and layup quality for AFP.
基金This study was financially supported by the National Natural Science Foundation of China(Grant/Award Number:22232004,22272179,21972068,and 22072067).
文摘Rational design and construction of oxygen reduction reaction(ORR)electrocatalysts with high activity,good stability,and low price are essential for the practical applications of renewable energy conversion devices,such as metal-air batteries.Electronic modification through constructing metal/semiconductor Schottky heterointerface represents a powerful strategy to enhance the electrochemical performance.Herein,we demonstrate a concept of Schottky electrocatalyst composed of uniform Co nanoparticles in situ anchored on the carbon nanotubes aligned on the carbon nanosheets(denoted as Co@N-CNTs/NSs hereafter)toward ORR.Both experimental findings and theoretical simulation testify that the rectifying contact could impel the voluntary electron flow from Co to N-CNTs/NSs and create an internal electric field,thereby boosting the electron transfer rate and improving the intrinsic activity.As a consequence,the Co@N-CNTs/NSs deliver outstanding ORR activity,impressive long-term durability,excellent methanol tolerance,and good performance as the air-cathode in the Zn-air batteries.The design concept of Schottky contact may provide the innovational inspirations for the synthesis of advanced catalysts in sustainable energy conversion fields.
基金The project was supported by the Foundation of Chinese Academy of Sciences.
文摘Heterojunctions between polyaniline (PANI) and n-type porous silicon (PS), Al/PS-PANI/Au cell, were fabricated, and the rectifying parameters of this heterojunction diode were measured as a function of the preparation conditions of PANI and PS, the electronic structure of PANI as well as cell structure. The rectifying parameters of Al/PS-PANI/Au cell were determined to be gamma = 1.8x10(1) similar to 1.0x10(5) for the rectifying ratio at 3V, n = 3 similar to 12 for the ideal factor, j(0) = 8.0x10(-5) similar to 5.6x10(-2) mA/cm(2) for the reversed saturated current density, and phi(0) = 0.67 similar to 0.83 V for the barrier height, respectively. The best rectifying heterojunction diode made between PANI and n-type PS with higher rectifying factor (gamma = 1.0x10(5) at 3V), output current (>1500 mA/cm(2) at 3V) and lower ideal factor (n = 3.3) was obtained by preventing the oxidation of PS before evaporating Al electrode.
文摘In wind power system,the randomness of wind energy increases the probability of components fault.once the switch fault of the PWM rectifier is detected,it will lead to the distortion of the motor voltage and current waveform,the increase of torque ripple,the fluctuation of filter capacitor voltage,and the increase of harmonic content,which will affect the control performance and operation safety of the system.A common fault in a three-phase PWM rectifier is the open-circuit fault of the switch.This paper analyzes the current waveform distortion of the square wave motor when the rectifier switch fault,and proposes different fault-tolerant control strategies for different situations of switch fault,include single,double and triple switches fault.This method is based on several special driving modes under power generation situation of square wave motor.The strategy is easy to implement and does not need to change the circuit topology.It can realize fault-tolerant control of switch faults in the same side half bridge or the same bridge arm of the three-phase PWM rectifier.The effectiveness of the proposed fault-tolerant strategy is verified by simulation and experiment at the end of the article.
基金supported in part by the European Union’s Horizon 2020 research and innovation program under grant agreement No.691714
文摘The diode rectifier unit(DRU)-based high-voltage DC(DRU-HVDC) system is a promising solution for offshore wind energy transmission thanks to its compact design, high efficiency, and strong reliability. Herein we investigate the feasibility of the DRU-HVDC system considering onshore and offshore AC grid faults, DC cable faults, and internal DRU faults. To ensure safe operation during the faults, the wind turbine(WT) converters are designed to operate in either current-limiting or voltage-limiting mode to limit potential excessive overcurrent or overvoltage. Strategies for providing fault currents using WT converters during offshore AC faults to enable offshore overcurrent and differential fault protection are investigated. The DRU-HVDC system is robust against various faults, and it can automatically restore power transmission after fault isolation. Simulation results confirm the system performance under various fault conditions.
基金Supported by the Shanghai Science Committee Project(No.Y232821D01)
文摘This paper presents an RF energy harvesting system for wireless intraocular pressure monitoring applications.The system consists of an implantable antenna and a rectifier.A new sizing strategy is adopted to optimize the conversion efficiency of the rectifier,and the design principle of an implantable antenna is introduced from material selection and structure design.Results from testing demonstrate that the antenna gain is about-20 dBi and the rectifier's maximum total conversion efficiency which contains match efficiency and rectifying efficiency is 47.18%under the implementation of0.18μm standard CMOS process.The maximum power obtained from the proposed system is 8μW when the power density of electromagnetic wave is lower than the national standard 40μW/cm^2 at915 MHz,which is enough to power the intraocular pressure monitoring system.
文摘Positron annihilation spectroscopy on GaN films grown on SiC substrate with MBE are presented. It is shown that the GaN/SiC interface is rectifying towards positrons, such that positrons can only travel from SiC to GaN and not vice versa. Potential steps seen by the positron at the GaN/SiC interface are calculated from experimental values of electron and positron work function. This “rectifying” effect has been successfully mimicked by inserting a thin region of very high electric field in the Variable Energy Positron Fit （VEPF） analysis. The built-in electric field is attributed to different positron affinities, dislocation and/or interface defects at the GaN/SiC interface.
基金Project supported by the National Natural Science Foundation of China (Grant No 10604038)the Program for New Century Excellent Talents in University,China (Grant No NCET-07-0472)
文摘An innovative heterojunction is fabricated between two sides of a freestanding thin film of HCl-doped polyaniline （PANI） derivative containing azobenzene side-chain, which is synthesized through an N-alkyl-substituted reaction. of the film, the side with being irradiated by UV light during preparation is represented as ＇A side＇; the other side without being irradiated is represented as ＇N side＇. The electrical properties of the heterojunction are measured and the rectifying effect is observed in the current voltage characteristic curves with the values of rectifying ratio （30 being 20 at ±0.06 V at T = 77 K and 4 at ±0.02 V at T = 300 K separately.
基金Project supported by the National Natural Science Foundation of China(Grant No.61078057)the Natural Science Foundation of Shannxi Province,China(Grant No.2011GM6013)+1 种基金the Northwestern Polytechnical University Foundation for Fundamental Research,China(Grant Nos.JC20110270 and JC201271)the Open Project of Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education,Lanzhou University,China(Grant No.LZUMMM2013001)
文摘ZnCo2O4/Si heterostructures have been fabricated by a pulsed laser deposition method, and their transport behaviors and photovoltaic properties have been characterized. The ZnCo2O4/Si heterostructures show a good rectifying behavior at five different temperatures ranging from 50 K to 290 K. The measurements of the photovoltaic response reveals that a photovoltage of 33 mV is generated when the heterostructures are illuminated by a 532 nm laser of 250 mW/cm^2 and mechanically chopped at 2500 Hz. Both the photocurrent and the photovoltage clearly increase with the increase of the laser intensity at room temperature. However, the heterostructures＇ photovoltage peak decreases with the increase of the temperature. This work may open new perspectives for ZnCo2O4/Si heterostructure-based devices.
基金supported by the National Natural Science Foundation of China (Grant No 10604038)Program for New Century Excellent Talents in University of China (Grant No NCET2007)
文摘This paper reports that the Schottky junctions between low work function metals （e.g. Al and In） and doped semiconducting polymer pellets （e.g. polyaniline （PANI） microsphere pellet and polypyrrole （PPy） nanotube pellet） have been prepared and studied. Since Ag is a high work function metal which can make an ohmic contact with polymer, silver paste was used to fabricate the electrodes. The Al/PANI/Ag heterojunction shows an obvious rectifying effect as shown in I - V characteristic curves （rectifying ratio γ = 5 at ±6 V bias at room temperature）. As compared to the Al/PANI/Ag, the heterojunction between In and PANI （In/PANI/Ag） exhibits a lower rectifying ratio γ= 1.6 at ±2 V bias at room temperature. In addition, rectifying effect was also observed in the heterojunctions Al/PPy/Ag （γ = 3.2 at ±1.6 V bias） and In/PPy/Ag （γ = 1.2 at ±3.0 V bias）. The results were discussed in terms of thermoionic emission theory.
基金Social Sciences Fund of Heilongjiang Province(06B002)
文摘The group of peasant laborer, being a beneficial group in present Chinese society, has already come into being, which is both outcome of duality and the important strength breaking duality in Chinese society. However, for a long time the severe maladjustments of peasant laborer group＇s not only engender the injustice of their position but also do harm to the development of social structure and economic growth in China. Therefore, describing the position of peasant laborer group and analyzing the consequence which causes by their imbalance position may have significant impact on perfecting Chinese social structure and attaining the objectives of combining the city with countryside in theory and practice.
基金Project supported by the National Basic Research Program of China (Grant No.2011CB612305)the National Natural Science Foundation of China (Grant No.51372064)+1 种基金the One Hundred Persons Project of Hebei Province of China (Grant No.CPRC001)the Science and Technology Research Project of Colleges and Universities in Hebei Province,China (Grant No.QN20131040)
文摘A Bi2Sr2Co2Oy/Si heterojunction is obtained by growing a layer of p-type oxygen-deficient Bi2Sr2Co2Oy film on a commercial n-type silicon wafer by pulsed laser deposition. Its rectifying and photovoltaic properties are studied in a wide temperature range from 20 K to 300 K. The transport mechanism under the forward bias can be attributed to a trap- filled space-charge-limited current conduction mechanism. Under the irradiation of a 532-nm continuous wave laser, a clear photovoltaic effect is observed and the magnitude ofphotovoltage increases as the temperature decreases, The results demonstrate the potential application of a Bi2SrzCo2Oy-based heterojunction in the photoelectronic devices.
文摘This paper explains step-by-step modeling and simulation of the full circuits of a battery control system and connected together starting from the AC input source to the battery control and storage system.The three-phase half-controlled rectifier has been designed to control and convert the AC power into DC power.In addition,two types of direct current converters have been used in this paper which are a buck and bidirectional DC/DC converters.These systems adjust the output voltage to be lower or higher than the input voltage.In the buck converters,the main switch operates in conduction or cut-off mode and is triggered by a Pulse-Width Modulated(PWM)signal.The output and input voltage levels ratio are used to calculate thePWMsignal’s duty cycle.Therefore,the duty cycle indicates the operation mode of the converter in steady-state operation.In this study,we analyze and control of a buck converter with the PWM signal.Besides,the bidirectional DC/DC converter has been achieved and optimized by PI control methods to control the battery charging and discharging modes.The simulation has been applied via the Matlab/Simulink environment.The results show the activity of each part of the designed circuits starting from the converters and the battery control system in charge and discharge modes.
基金the National High Technology Research and Development Program(863)of China(No.2012AA062001)
文摘In view of the complexity and uncertainty of system, both the state performances and state probabilities of multi-state components can be expressed by interval numbers. The belief function theory is used to characterize the uncertainty caused by various factors. A modified Markov model is proposed to obtain the state probabilities of components at any given moment and subsequently the mass function is used to represent the precise belief degree of state probabilities. Based on the primary studies of universal generating function(UGF)method, a belief UGF(BUGF) method is utilized to analyze the reliability and the uncertainty of excavator rectifier feedback system. This paper provides an available method to evaluate the reliability of multi-state systems(MSSs) with interval state performances and state probabilities, and also avoid the interval expansion problem.
基金Deanship of Scientific Research at King Khalid University for funding this work through Large Group Research Project under Grant Number RGP2/162/44.
文摘Security systems are the need of the hour to protect data from unauthorized access.The dissemination of confidential information over the public network requires a high level of security.The security approach such as steganography ensures confidentiality,authentication,integrity,and non-repudiation.Steganography helps in hiding the secret data inside the cover media so that the attacker can be confused during the transmission process of secret data between sender and receiver.Therefore,we present an efficient hybrid security model that provides multifold security assurance.To this end,a rectified Advanced Encryption Standard(AES)algorithm is proposed to overcome the problems existing in AES such as pattern appearance and high computations.The modified AES is used for the encryption of the stego image that contains the digitally signed encrypted secret data.The enciphering and deciphering of the secret data are done using the Rivest–Shamir–Adleman(RSA)algorithm.The experiments are conducted on the images of the USC-SIPI standard image database.The experimental results prove that the proposed hybrid system outperforms other SOTA(state-of-the-art)approaches.
基金supported by the National Key R&D Program of China(No.2017YFE0300104)National Natural Science Foundation of China(No.51821005)
文摘The acceleration grid power supply(AGPS) is a crucial part of the Negative-ion Neutral Beam Injection system in the China Fusion Engineering Test Reactor,which includes a 3-phase passive(diode) rectifier.To diagnose and localize faults in the rectifier,this paper proposes a frequencydomain analysis-based fault diagnosis algorithm for the rectifier in AGPS.First,time-domain expressions and spectral characteristics of the output voltage of the TPTL-NPC inverter-based power supply are analyzed.Then,frequency-domain analysis-based fault diagnosis and frequency-domain analysis-based sub-fault diagnosis algorithms are proposed to diagnose open circuit(OC) faults of diode(s),which benefit from the analysis of harmonics magnitude and phase-angle of the output voltage.Only a fundamental period is needed to diagnose and localize exact faults,and a strong Variable-duration Fault Detection Method is proposed to identify acceptable ripple from OC faults.Detailed simulations and experimental results demonstrate the effectiveness,quickness,and robustness of the proposed algorithms,and the diagnosis algorithms proposed in this article provide a significant method for the fault diagnosis of other rectifiers and converters.
文摘The design of multiband microstrip rectenna for radio frequency energy harvesting applications is presented in this paper. The designed antenna has good performance in the GSM-900/1800, WiFi and WLAN bands. In addition, the rectifier circuit is designed at multi resonant frequencies to collect the largest amount of RF ambient power from different RF sources. The developed antenna is matched with the rectifier at four desired frequencies using several rectifier branches to collect the largest of RF power. The proposed rectenna is printed on FR4 substrate with modified ground plane to achieve suitable impedance bandwidth. The proposed antenna consists of elliptical radiating plane with stubs and stepped modified ground plane. The rectenna resonates at quad frequency bands at (GSM 900/1800, WiFi band and WLAN bands) with rectifier power conversion efficiency up to 56.4% at 0 dBm input power using the HSMS-2850 Schottky diode. The efficiency is more enhanced by using SMS-7630-061 Schottky diode which is characterized by a low junction capacitance and a low threshold voltage to achieve higher conversion efficiency up to 71.1% at the same 0 dBm input power for the same resonating frequency band.
基金Supported by the Science and Technology Plan of Hunan Province under Grant No 2014SK3274
文摘We report ab initio calculations of the transport behavior of a phenyl substituted molecular motor. The calculated results show that the transport behavior of the device is sensitive to the rotation degree of the rotor part. When the rotor part is parallel with the stator part, a better rectifying performance can be found in the current-voltage curve. However, when the rotor part revolves to vertical with the stator part, the currents in the positive bias region decrease slightly. More importantly, the rectifying performance disappears. Thus this offers us a new method to modulate the rectifying behavior in molecular devices.
