Permanent magnet synchronous motors(PMSMs), owing to the features of low maintenance costs, great efficiency, and high power density, are extensively utilized in applications such as rail transportation, industrial ro...Permanent magnet synchronous motors(PMSMs), owing to the features of low maintenance costs, great efficiency, and high power density, are extensively utilized in applications such as rail transportation, industrial robots, and new energy electric vehicles. However, the application of space vector pulse width modulation(SVPWM) results in the motor phase current exhibiting clustered harmonic distributions at the integer multiples of the switching frequency, leading to motor noise and vibration issues. To address the issues, this paper proposes a three-random SVPWM(TRPWM) strategy based on a threestate Markov chain, integrating random pulse position, random switching frequency, and random small vector dwell time. By adhering to the principle of voltage-second balance, this strategy spreads the concentrated high-frequency harmonics over a wider frequency range, significantly reducing the magnitude of the concentrated harmonics in the phase current. Comparative experiments with conventional SVPWM, conventional dual-random SVPWM, and conventional three-random SVPWM strategies demonstrate that the proposed approach achieves the expansion of harmonics at integer multiples of the switching frequency in the phase current, effectively suppressing high-frequency vibrations in PMSMs.展开更多
A fragility calculation scheme is estabtished in this paper for porcelain-type equipments subjected to random earthquake ground motions. All steps of the method are illustrated by the seismic damage analysis of GW4-11...A fragility calculation scheme is estabtished in this paper for porcelain-type equipments subjected to random earthquake ground motions. All steps of the method are illustrated by the seismic damage analysis of GW4-110 disconnect switch. The model of the equipment is built applying the finite element method with flexible joints, and the seismic response of the equipment is analyzed using elastic time history method. On the base, according to the strength damage index and Monte-Carlo Method, the seismic damage ratios are counted and the seismic fragility curves are presented. Then the seismic damage of GW4-110 disconnect switch can be predicted.展开更多
With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on ...With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings.展开更多
Cu/HfOx/n^＋Si devices are fabricated to investigate the influence of technological parameters including film thickness and Ar/02 ratio on the resistive switching （RS） characteristics of HfOx films, in terms of swit...Cu/HfOx/n^＋Si devices are fabricated to investigate the influence of technological parameters including film thickness and Ar/02 ratio on the resistive switching （RS） characteristics of HfOx films, in terms of switch ratio, endurance properties, retention time and multilevel storage. It is revealed that the RS characteristics show strong dependence on technological parameters mainly by altering the defects （oxygen vacancies） in the film. The sample with thickness of 2Onto and Ar/O2 ratio of 12：3 exhibits the best RS behavior with the potential of multilevel storage. The conduction mechanism of all the films is interpreted based on the filamentary model.展开更多
The paper is concerned with stabilization problem for a class of stochastic switching systems with time-delay in the detection of switching signal. By using binomial model,Poisson process,and Wiener process to describ...The paper is concerned with stabilization problem for a class of stochastic switching systems with time-delay in the detection of switching signal. By using binomial model,Poisson process,and Wiener process to describe time-delay, switching signal, and exogenous disturbance, respectively, the system under investigation is entirely set in a stochastic framework. The influence of the random time-delay is combined into reconstructing the switching signal of overall closed-loop system and changes the distribution property of switching points. Therefore,based on the asymptotical behaviors of Poisson processes and Wiener processes,the almost surely exponential stability conditions are established. Furthermore,a design methodology is posed for solving the stabilization control.展开更多
In this paper, a WO3-based resistive random access memory device composed of a thin film of WO3 sandwiched between a copper top and a platinum bottom electrodes is fabricated by electron beam evaporation at room tempe...In this paper, a WO3-based resistive random access memory device composed of a thin film of WO3 sandwiched between a copper top and a platinum bottom electrodes is fabricated by electron beam evaporation at room temperature. The reproducible resistive switching, low power consumption, multilevel storage possibility, and good data retention characteristics demonstrate that the Cu/WO3/Pt memory device is very promising for future nonvolatile memory applications. The formation and rupture of localised conductive filaments is suggested to be responsible for the observed resistive switching behaviours.展开更多
We report that fully transparent resistive random access memory （TRRAM） devices based on ITO/TiO2/ITO sandwich structure, which are prepared by the method of RF magnetron sputtering, exhibit excellent switching stab...We report that fully transparent resistive random access memory （TRRAM） devices based on ITO/TiO2/ITO sandwich structure, which are prepared by the method of RF magnetron sputtering, exhibit excellent switching stability. In the visible region （400 800 nm in wavelength） the TRRAM device has a transmittance of more than 80%. The fabricated TRRAM device shows a bipolar resistance switching behaviour at low voltage, while the retention test and rewrite cycles of more than 300,000 indicate the enhancement of switching capability. The mechanism of resistance switching is further explained by the forming and rupture processes of the filament in the TiO2 layer with the help of more oxygen vacancies which are provided by the transparent ITO electrodes.展开更多
In this paper, the bipolar resistive switching characteristic is reported in Ti/ZrO2/Pt resistive switching memory de- vices. The dominant mechanism of resistive switching is the formation and rupture of the conductiv...In this paper, the bipolar resistive switching characteristic is reported in Ti/ZrO2/Pt resistive switching memory de- vices. The dominant mechanism of resistive switching is the formation and rupture of the conductive filament composed of oxygen vacancies. The conduction mechanisms for low and high resistance states are dominated by the ohmic conduc- tion and the trap-controlled space charge limited current （SCLC） mechanism, respectively. The effect of a set compliance current on the switching parameters is also studied： the low resistance and reset current are linearly dependent on the set compliance current in the log-log scale coordinate; and the set and reset voltage increase slightly with the increase of the set compliance current. A series circuit model is proposed to explain the effect of the set compliance current on the resistive switching behaviors.展开更多
We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer（Agilent B1500A）,and the relative micro...We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer（Agilent B1500A）,and the relative micro-analysis of I-V characteristics of VOx/Cu is characterized by using a conductive atomic force microscope（CAFM）.The I-V test results indicate that both the forming and the reversible resistive switching between low resistance state（LRS） and high resistance state（HRS） can be observed under either positive or negative sweep.The CAFM images for LRS and HRS directly exhibit evidence for the formation and rupture of filaments based on positive or negative voltage.The Cu/VOx/Cu sandwiched structure exhibits reversible resistive switching behavior and shows potential applications in the next generation of nonvolatile memory.展开更多
The fully transparent indium-tin-oxide/BaSnO3/F-doped SnO2 devices that show a stable bipolar resistance switching effect are successfully fabricated. In addition to the transmittance being above 87% for visible light...The fully transparent indium-tin-oxide/BaSnO3/F-doped SnO2 devices that show a stable bipolar resistance switching effect are successfully fabricated. In addition to the transmittance being above 87% for visible light, an initial forming process is unnecessary for the production of transparent memory. Fittings to the current-voltage curves reveal the interfacial conduction in the devices. The first-principles calculation indicates that the oxygen vacancies in cubic BaSnO3 will form the defective energy level below the bottom of conduction band. The field-induced resistance change can be explained based on the change of the interracial Schottky barrier, due to the migration of oxygen vacancies in the vicinity of the interface. This work presents a candidate material BaSnO3 for the application of resistive random access memory to transparent electronics.展开更多
This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and t...This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and the interface type. Here, we adopt the filament type to study the metal oxide based resistive switch- ing memory, which considers the migration of metallic cations and oxygen vacancies, as well as discuss two main mechanisms including the electrochemical metallization effect （ECM） and valence change memory effect （VCM）. At the light of the influence of the electrode materials and switching layers on the RS char- acteristics, an overview has also been given on the performance parameters including the uniformity, endurance, the retention, and the multi-layer storage. Especially, we mentioned ITO （indium tin oxide） electrode and discussed the novel RS characteristics related with ITO. Finally, the challenges resistive random access memory （RRAM） device is facing, as well as the future development trend, are expressed.展开更多
Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can...Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can be divided into two categories： graphene RRAM and graphene oxide （GO）/reduced graphene oxide （rGO） RRAM. Using graphene as the electrode, GRRAM can own many good characteristics, such as low power consumption, higher density, transparency, SET voltage modulation, high uniformity, and so on. Graphene flakes sandwiched between two dielectric layers can lower the SET voltage and achieve multilevel switching. Moreover, the GRRAM with rGO and GO as the dielectric or electrode can be simply fabricated. Flexible and high performance RRAM and GO film can be modified by adding other materials layer or making a composite with polymer, nanoparticle, and 2D materials to further improve the performance. Above all, GRRAM shows huge potential to become the next generation memory.展开更多
The rapid expansion of railways,especially High-Speed Railways(HSRs),has drawn considerable interest from both academic and industrial sectors.To meet the future vision of smart rail communications,the rail transport ...The rapid expansion of railways,especially High-Speed Railways(HSRs),has drawn considerable interest from both academic and industrial sectors.To meet the future vision of smart rail communications,the rail transport industry must innovate in key technologies to ensure high-quality transmissions for passengers and railway operations.These systems must function effectively under high mobility conditions while prioritizing safety,ecofriendliness,comfort,transparency,predictability,and reliability.On the other hand,the proposal of 6 G wireless technology introduces new possibilities for innovation in communication technologies,which may truly realize the current vision of HSR.Therefore,this article gives a review of the current advanced 6 G wireless communication technologies for HSR,including random access and switching,channel estimation and beamforming,integrated sensing and communication,and edge computing.The main application scenarios of these technologies are reviewed,as well as their current research status and challenges,followed by an outlook on future development directions.展开更多
基金supported by the Pioneer Project of Zhejiang Province under Grant 2024C01014the National Natural Science Foundation of China under Grants 52177055 and 52277064。
文摘Permanent magnet synchronous motors(PMSMs), owing to the features of low maintenance costs, great efficiency, and high power density, are extensively utilized in applications such as rail transportation, industrial robots, and new energy electric vehicles. However, the application of space vector pulse width modulation(SVPWM) results in the motor phase current exhibiting clustered harmonic distributions at the integer multiples of the switching frequency, leading to motor noise and vibration issues. To address the issues, this paper proposes a three-random SVPWM(TRPWM) strategy based on a threestate Markov chain, integrating random pulse position, random switching frequency, and random small vector dwell time. By adhering to the principle of voltage-second balance, this strategy spreads the concentrated high-frequency harmonics over a wider frequency range, significantly reducing the magnitude of the concentrated harmonics in the phase current. Comparative experiments with conventional SVPWM, conventional dual-random SVPWM, and conventional three-random SVPWM strategies demonstrate that the proposed approach achieves the expansion of harmonics at integer multiples of the switching frequency in the phase current, effectively suppressing high-frequency vibrations in PMSMs.
基金supported by the Science and Technology Commission of Shanghai Municipality (Grant No.04JC14035)
文摘A fragility calculation scheme is estabtished in this paper for porcelain-type equipments subjected to random earthquake ground motions. All steps of the method are illustrated by the seismic damage analysis of GW4-110 disconnect switch. The model of the equipment is built applying the finite element method with flexible joints, and the seismic response of the equipment is analyzed using elastic time history method. On the base, according to the strength damage index and Monte-Carlo Method, the seismic damage ratios are counted and the seismic fragility curves are presented. Then the seismic damage of GW4-110 disconnect switch can be predicted.
基金Project supported by the National Natural Science Foundation of China (Grant No. 60921062)
文摘With the progress of the semiconductor industry,the resistive random-access memory（RAM） has drawn increasing attention.The discovery of the memristor has brought much attention to this study.Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms.We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models.Finally,simulations are presented.We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms,which are applied to explain their resistive switchings.
基金Supported by the National Natural Science Foundation of China under Grant No 51202196the National Aerospace Science Foundation of China under Grant No 2013ZF53067+2 种基金the Natural Science Basic Research Plan in Shaanxi Province of China under Grant No 2014JQ6204the Fundamental Research Funds for the Central Universities under Grant No 3102014JCQ01032the 111 Project under Grant No B08040
文摘Cu/HfOx/n^＋Si devices are fabricated to investigate the influence of technological parameters including film thickness and Ar/02 ratio on the resistive switching （RS） characteristics of HfOx films, in terms of switch ratio, endurance properties, retention time and multilevel storage. It is revealed that the RS characteristics show strong dependence on technological parameters mainly by altering the defects （oxygen vacancies） in the film. The sample with thickness of 2Onto and Ar/O2 ratio of 12：3 exhibits the best RS behavior with the potential of multilevel storage. The conduction mechanism of all the films is interpreted based on the filamentary model.
基金Sponsored by the Natural Science Foundation of Heilongjiang Province of China(Grant No.LC201428,F201429)
文摘The paper is concerned with stabilization problem for a class of stochastic switching systems with time-delay in the detection of switching signal. By using binomial model,Poisson process,and Wiener process to describe time-delay, switching signal, and exogenous disturbance, respectively, the system under investigation is entirely set in a stochastic framework. The influence of the random time-delay is combined into reconstructing the switching signal of overall closed-loop system and changes the distribution property of switching points. Therefore,based on the asymptotical behaviors of Poisson processes and Wiener processes,the almost surely exponential stability conditions are established. Furthermore,a design methodology is posed for solving the stabilization control.
基金Project supported by the National Basic Research Program of China(Grant Nos.2008CB925002 and 2010CB934200)the National Natural Science Foundation of China(Grant Nos.60825403 and 50972160)the National High Technology Research and Development Program of China(Grant No.2009AA03Z306)
文摘In this paper, a WO3-based resistive random access memory device composed of a thin film of WO3 sandwiched between a copper top and a platinum bottom electrodes is fabricated by electron beam evaporation at room temperature. The reproducible resistive switching, low power consumption, multilevel storage possibility, and good data retention characteristics demonstrate that the Cu/WO3/Pt memory device is very promising for future nonvolatile memory applications. The formation and rupture of localised conductive filaments is suggested to be responsible for the observed resistive switching behaviours.
基金Project supported by the National Basic Research Program of China (Grant No. 2007CB925002)the National High Technology Research and Development Program of China (Grant No. 2008AA031401)and Chinese Academy of Sciences
文摘We report that fully transparent resistive random access memory （TRRAM） devices based on ITO/TiO2/ITO sandwich structure, which are prepared by the method of RF magnetron sputtering, exhibit excellent switching stability. In the visible region （400 800 nm in wavelength） the TRRAM device has a transmittance of more than 80%. The fabricated TRRAM device shows a bipolar resistance switching behaviour at low voltage, while the retention test and rewrite cycles of more than 300,000 indicate the enhancement of switching capability. The mechanism of resistance switching is further explained by the forming and rupture processes of the filament in the TiO2 layer with the help of more oxygen vacancies which are provided by the transparent ITO electrodes.
基金supported by the National Basic Research Program of China(Grant No.2011CBA00606)the National Natural Science Foundation of China(Grant Nos.61106106,11304237,61376099,and 11235008)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant Nos.20130203130002 and 20110203110012)
文摘In this paper, the bipolar resistive switching characteristic is reported in Ti/ZrO2/Pt resistive switching memory de- vices. The dominant mechanism of resistive switching is the formation and rupture of the conductive filament composed of oxygen vacancies. The conduction mechanisms for low and high resistance states are dominated by the ohmic conduc- tion and the trap-controlled space charge limited current （SCLC） mechanism, respectively. The effect of a set compliance current on the switching parameters is also studied： the low resistance and reset current are linearly dependent on the set compliance current in the log-log scale coordinate; and the set and reset voltage increase slightly with the increase of the set compliance current. A series circuit model is proposed to explain the effect of the set compliance current on the resistive switching behaviors.
基金Project supported by the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No. NCET-11-1064)the Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 61101055,61274113,and 11204212)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20100032120029)Tianjin Natural Science Foundation of China (Grant No. 10SYSYJC27700)
文摘We demonstrate the polarization of resistive switching for a Cu/VOx/Cu memory cell.The switching behaviors of Cu/VOx/Cu cell are tested by using a semiconductor device analyzer（Agilent B1500A）,and the relative micro-analysis of I-V characteristics of VOx/Cu is characterized by using a conductive atomic force microscope（CAFM）.The I-V test results indicate that both the forming and the reversible resistive switching between low resistance state（LRS） and high resistance state（HRS） can be observed under either positive or negative sweep.The CAFM images for LRS and HRS directly exhibit evidence for the formation and rupture of filaments based on positive or negative voltage.The Cu/VOx/Cu sandwiched structure exhibits reversible resistive switching behavior and shows potential applications in the next generation of nonvolatile memory.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11174135 and 60976016)the National 973 Project,China(Gant No.0213117005)+3 种基金the State Key Program for Basic Research of China(Grant No.2010CB630704)the Science Foundation of Henan Province,China(Grant No.14A430020)the Science Foundation of Henan University,China(Grant No.SBGJ090503)China Postdoctoral Science Foundation(Grant No.2012M511250)
文摘The fully transparent indium-tin-oxide/BaSnO3/F-doped SnO2 devices that show a stable bipolar resistance switching effect are successfully fabricated. In addition to the transmittance being above 87% for visible light, an initial forming process is unnecessary for the production of transparent memory. Fittings to the current-voltage curves reveal the interfacial conduction in the devices. The first-principles calculation indicates that the oxygen vacancies in cubic BaSnO3 will form the defective energy level below the bottom of conduction band. The field-induced resistance change can be explained based on the change of the interracial Schottky barrier, due to the migration of oxygen vacancies in the vicinity of the interface. This work presents a candidate material BaSnO3 for the application of resistive random access memory to transparent electronics.
基金financial support from the National Natural Science Foundation of China(Nos.61474039 and 51572002)the Nature Science Foundation(Key Project) of Hubei Province (No.2015CFA052)
文摘This review summarizes the mechanism and performance of metal oxide based resistive switching memory. The origin of resistive switching （RS） behavior can be roughly classified into the conducting filament type and the interface type. Here, we adopt the filament type to study the metal oxide based resistive switch- ing memory, which considers the migration of metallic cations and oxygen vacancies, as well as discuss two main mechanisms including the electrochemical metallization effect （ECM） and valence change memory effect （VCM）. At the light of the influence of the electrode materials and switching layers on the RS char- acteristics, an overview has also been given on the performance parameters including the uniformity, endurance, the retention, and the multi-layer storage. Especially, we mentioned ITO （indium tin oxide） electrode and discussed the novel RS characteristics related with ITO. Finally, the challenges resistive random access memory （RRAM） device is facing, as well as the future development trend, are expressed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61574083 and 61434001)the National Basic Research Program of China(Grant No.2015CB352101)+4 种基金the National Key Research and Development Program of China(Grant No.2016YFA0200404)the National Key Project of Science and Technology of China(Grant No.2011ZX02403-002)Special Fund for Agroscientic Research in the Public Interest of China(Grant No.201303107)the Independent Research Program of Tsinghua University,China(Grant No.2014Z01006)Advanced Sensor and Integrated System Lab of Tsinghua University Graduate School at Shenzhen,China(Grant No.ZDSYS20140509172959969)
文摘Graphene-based resistive random access memory （GRRAM） has grasped researchers＇ attention due to its merits com- pared with ordinary RRAM. In this paper, we briefly review different types of GRRAMs. These GRRAMs can be divided into two categories： graphene RRAM and graphene oxide （GO）/reduced graphene oxide （rGO） RRAM. Using graphene as the electrode, GRRAM can own many good characteristics, such as low power consumption, higher density, transparency, SET voltage modulation, high uniformity, and so on. Graphene flakes sandwiched between two dielectric layers can lower the SET voltage and achieve multilevel switching. Moreover, the GRRAM with rGO and GO as the dielectric or electrode can be simply fabricated. Flexible and high performance RRAM and GO film can be modified by adding other materials layer or making a composite with polymer, nanoparticle, and 2D materials to further improve the performance. Above all, GRRAM shows huge potential to become the next generation memory.
基金National Natural Science Foundation of China(U2468201,62122012,62221001).
文摘The rapid expansion of railways,especially High-Speed Railways(HSRs),has drawn considerable interest from both academic and industrial sectors.To meet the future vision of smart rail communications,the rail transport industry must innovate in key technologies to ensure high-quality transmissions for passengers and railway operations.These systems must function effectively under high mobility conditions while prioritizing safety,ecofriendliness,comfort,transparency,predictability,and reliability.On the other hand,the proposal of 6 G wireless technology introduces new possibilities for innovation in communication technologies,which may truly realize the current vision of HSR.Therefore,this article gives a review of the current advanced 6 G wireless communication technologies for HSR,including random access and switching,channel estimation and beamforming,integrated sensing and communication,and edge computing.The main application scenarios of these technologies are reviewed,as well as their current research status and challenges,followed by an outlook on future development directions.
