This paper addresses the challenges in the teaching of electrical and electronic technology in higher vocational colleges and proposes specific countermeasures to improve teaching quality and effectiveness.The counter...This paper addresses the challenges in the teaching of electrical and electronic technology in higher vocational colleges and proposes specific countermeasures to improve teaching quality and effectiveness.The countermeasures include optimizing teaching content,emphasizing practical application and innovation,innovating teaching methods,introducing modern instructional approaches,strengthening the teaching team,enhancing teacher quality and practical expertise,upgrading experimental equipment and facilities,enriching curriculum resources,and incorporating digital teaching materials.These measures aim to cultivate high-quality skilled talents,promote social and economic development,and enhance national competitiveness.By adjusting the course structure,incorporating real-world industry cases,and fostering collaboration with enterprises,students can better understand and apply electrical and electronic technology.The introduction of project-based teaching,flipped classrooms,and multimedia technology can enhance student engagement and facilitate independent learning.Furthermore,the improvement of experimental resources and the establishment of online teaching platforms can enhance students’practical skills and provide a variety of learning resources.These measures contribute to the overall improvement of electrical and electronic technology teaching in higher vocational colleges.展开更多
With the advancement of vocational education reform,education informationization,and digitalization have become the important direction of the reform of electrical and electronic teaching in high vocational colleges.I...With the advancement of vocational education reform,education informationization,and digitalization have become the important direction of the reform of electrical and electronic teaching in high vocational colleges.In this context,intelligent product development of professional electrical and electronic teaching should also do a good job in practice and innovation,especially in actively building a digital experimental teaching platform and promoting the reform of experimental teaching mode,so that students can learn more useful knowledge and skills in the new platform,and cultivate more applied and skilled talents for society.While analyzing the problems existing in the traditional electrical and electronic experimental teaching mode,this paper analyzes the significance and practical path of the construction of electrical and electronic experimental teaching platforms in higher vocational colleges which can be of reference in future research.展开更多
The teaching ability competition is a vital method for stimulating teachers’enthusiasm and enhancing their teaching skills.This approach has gained increasing attention from colleges and universities in recent years....The teaching ability competition is a vital method for stimulating teachers’enthusiasm and enhancing their teaching skills.This approach has gained increasing attention from colleges and universities in recent years.The competition focuses on evaluating teachers’capabilities in designing and implementing lessons,encouraging the exchange of new educational ideas and high-quality teaching methods.Reforming the teaching of Electrical and Electronic Technology courses based on insights from teaching competitions can significantly improve teaching quality.This paper explores the teaching design and implementation of the Electrical and Electronic Technology course,drawing on the principles of teaching ability competitions.First,it analyzes the existing problems in teaching this course.Then,it highlights the significant benefits that teaching competitions bring to the course.Based on these insights,the paper proposes practical strategies aimed at enhancing students’interest and practical skills,thereby promoting innovative developments in teaching Electrical and Electronic Technology.展开更多
Oxygen evolution reaction(OER)as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years.But,it still maintains the challenge to manipulate the geometric an...Oxygen evolution reaction(OER)as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years.But,it still maintains the challenge to manipulate the geometric and electronic structure during single reaction process under the same conditions.Herein,we report a simple self-template strategy to generate honeycomb-like Ni_(2)P/N,P-C hybrids with preferred electronic architecture.Experiments coupled with theoretical results revealed that the synthesized catalyst has two characteristics:firstly,the unique honeycomb-like morphology not only enables the fully utilization of catalytic active sites but also optimizes the mass/electron transportation pathway,which favor the diffusion of electrolyte to accessible active sites.Secondly,N,P-C substrate,on the one hand,largely contributes the electronic distribution near Fermi level(E_(F))thus boosting its electrical conductivity.On the other hand,the support effect result in the upshift of d-band center and electropositivity of Ni sites,which attenuates the energy barrier for the adsorption of OH~àand the formation of*OOH.In consequence,the optimized Ni_(2)P/N,P-C catalysts feature high electrocatalytic activity towards OER(a low overpotential of 252 m V to achieve10 m A cm^(-2))and 10 h long-term stability,the outstanding performance is comparable to most of transition metal catalysts.This work gives a innovative tactics for contriving original OER electrocatalysts,inspirng deeper understanding of fabricating catalysts by combining theoretical simulation and experiment design.展开更多
With the rapid development of autonomous vehicles,more and more functions and computing requirements have led to the continuous centralization in the topology of electrical and electronic(E/E)architectures.While certa...With the rapid development of autonomous vehicles,more and more functions and computing requirements have led to the continuous centralization in the topology of electrical and electronic(E/E)architectures.While certain Tier1 suppliers,such as BOSCH,have previously proposed a serial roadmap for E/E architecture development,implemented since 2015 with significant contributions to the automotive industry,lingering misconceptions and queries persist in actual engineering processes.Notably,there are concerns regarding the perspective of zone-oriented E/E architectures,characterized by zonal concentration,as successors to domain-oriented E/E architectures,known for functional concentration.Addressing these misconceptions and queries,this study introduces a novel parallel roadmap for E/E architecture development,concurrently evaluating domain-oriented and zone-oriented schemes.Furthermore,the study explores hybrid E/E architectures,amalgamating features from both paradigms.To align with the evolution of E/E architectures,networking technologies must adapt correspondingly.The networking mechanisms pivotal in E/E architecture design are comprehensively discussed.Additionally,the study delves into modeling and verification tools pertinent to E/E architecture topologies.In conclusion,the paper outlines existing challenges and unresolved queries in this domain.展开更多
Equating the Rest Mass Energy of a free electron to its Rest Charge Energy we prove that the electron cannot be a dimensionless point particle because if it were dimensionless, it would contain an infinite amount of R...Equating the Rest Mass Energy of a free electron to its Rest Charge Energy we prove that the electron cannot be a dimensionless point particle because if it were dimensionless, it would contain an infinite amount of Rest Charge Energy at the location of its charge since r = 0 gives , which is clearly not possible. Since the electron has no internal structure, equating its Rest Mass Energy to its Rest Charge Energy, we calculate the electron to be a sphere of radius 4.68 × 10<sup>-</sup><sup>16</sup> meters. We calculate the Electric Field at the surface of the electron due to its charge and the Repulsive Force two electrons in proximity exert on each other.展开更多
In this work, the possible structures of electron and proton have been explored. Based on the potential expressions of electron and proton, we found that the electron and proton share the similar structure inside re a...In this work, the possible structures of electron and proton have been explored. Based on the potential expressions of electron and proton, we found that the electron and proton share the similar structure inside re and rn. And within re and rn, the conventional charge concept stops working, the same charge repelling force doesn’t exist anymore and as a result, the requirement of charge conservation is automatically removed. Whereas beyond re and rn, the potential expressions of electron and proton obey the point charge potentials as we normally understand. Therefore, the conventional charge concept can be applied and the requirement of charge conservation takes effect. Furthermore, a possible mechanism for the creations of electric monopole and magnetic monopole is discussed. In addition, to compare the particle size in micro-world, the balloon criterion is proposed. By this balloon criterion, the proton is determined about 10 times bigger than electron. From the physical picture about electron and proton described above, the stabilities of electron and proton can be explained quite well.展开更多
The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric an...The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles.展开更多
Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lph...Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lphosporic acid buffer. After three washes in a buffer solution the tissue was fixedin a mixture of 1% osmium tetraoxide at 4℃ for 1h. The tissue was dehydrated in graded ethandethanols and dried. The tissue was examined and photographed with an SEM at an accelerating voltage展开更多
With the progress of computer technology, CAD technique is urgent needed. In this paper, we conduct numerical and theoretical analysis and research on computer aided design technique and novel pattern for electronic a...With the progress of computer technology, CAD technique is urgent needed. In this paper, we conduct numerical and theoretical analysis and research on computer aided design technique and novel pattern for electronic architectural drawing and perspective. AUTOCAD drawing soRware because of its versatility and easy entry, in engineering has broad user base, but also because of the basis of general drawing software, often cannot directly use of the existing order efficiently complete professional drawing. We modify the current pattern and introduce our proposed pattern for advancement. The experiment proves the effectiveness of the pattern. In addition, we will conduct more insightful research in the future to nolish the current anoroach.展开更多
China’s largest electronic piano specialized production factory—the Shanghai Huaxin Electronics and Electrical Appliances General Factory—developed and grew up from a small loss-incurring neighborhood factory a dec...China’s largest electronic piano specialized production factory—the Shanghai Huaxin Electronics and Electrical Appliances General Factory—developed and grew up from a small loss-incurring neighborhood factory a decade ago. At present, the factory’s annual output value has exceeded RMB100 million for three years running, and sales are increasing at a rate of 30 percent per year.展开更多
The waste derived from Electrical and Electronic Equipment (WEEE) is of interest now worldwide, in some countries due to the rapid technological development and in others due to technological dependence through the ac...The waste derived from Electrical and Electronic Equipment (WEEE) is of interest now worldwide, in some countries due to the rapid technological development and in others due to technological dependence through the acquisition of second hand equipment. Therefore it is necessary to implement strategies for the sustainable management of electrical and electronic equipment at the end of its useful life. This paper presents the results of an investigation that was conducted in a city located in the Northwest of Mexico, which seeks to understand the management practices of household WEEE generators. A survey was applied to a representative sample of the population with a confidence level of 90%. Six home appliances were quantified and it was found that approximately 21% of them are disposed directly as part of the household flow of Municipal Solid Waste (MSW), while 79% are storage for a latter sale, repair or reuse. The results obtained support the need to develop evaluations and to implement possible scenarios for the sustainable management of Electrical and Electronic Waste.展开更多
This paper presents the study and application of the electronic device anti-interference techniques underhigh voltage and/or heavy current electro-magnetic circumstance in power system.[
Total Electron Content(TEC)and electron density enhancement were observed on the day before 17 March 2015 great storm in the China Region.Observations from ground-and space-based instruments are used to investigate th...Total Electron Content(TEC)and electron density enhancement were observed on the day before 17 March 2015 great storm in the China Region.Observations from ground-and space-based instruments are used to investigate the temporal and spatial evolution of the pre-storm enhancement.TEC enhancement was observed from 24°N to 30°N after 10:00 UT at 105°E,110°E and 115°E longitudes on March 16.The maximum magnitude of TEC enhancement was more than 10 TECU and the maximal relative TEC enhancement exceeded 30%.Compared with geomagnetic quiet days,the electron density of Equatorial Ionization Anomaly(EIA)northern peak from Swarm A/C satellites on March 16 was larger and at higher latitudes.NmF2 enhanced during 11:30—21:00 UT at Shaoyang Station and increased by 200%at~16:00 UT.However,TEC and electron density enhancement were not accompanied by a significant change of hmF2.Most research has excluded some potential mechanisms as the main driving factors for storm-time density enhancements by establishing observational constraints.In this paper,we observed pre-storm enhancement in electron density at different altitudes and Equatorial Electrojet(EEJ)strength results derived from ground magnetometers observations suggest an enhanced eastward electric field from the E region probably played a significant role in this event.展开更多
The rapid consumption of fossil fuel and increased environmental damage caused by it have given a strong impetus to the growth and development of fuelefficient vehicles. Hybrid electric vehicles (HEVs) have evolved fr...The rapid consumption of fossil fuel and increased environmental damage caused by it have given a strong impetus to the growth and development of fuelefficient vehicles. Hybrid electric vehicles (HEVs) have evolved from their inchoate state and are proving to be a promising solution to the serious existential problem posed to the planet earth. Not only do HEVs provide better fuel economy and lower emissions satisfying environmental legislations, but also they dampen the effect of rising fuel prices on consumers. HEVs combine the drive powers of an internal combustion engine and an electrical machine. The main components of HEVs are energy storage system, motor, bidirectional converter and maximum power point trackers (MPPT, in case of solar-powered HEVs). The performance of HEVs greatly depends on these components and its architecture. This paper presents an extensive review on essential components used in HEVs such as their architectures with advantages and disadvantages, choice of bidirectional converter to obtain high efficiency, combining ultracapacitor with battery to extend the battery life, traction motors’ role and their suitability for a particular application. Inclusion of photovoltaic cell in HEVs is a fairly new concept and has been discussed in detail. Various MPPT techniques used for solar-driven HEVs are also discussed in this paper with their suitability.展开更多
The effect of an electric field E on a narrow quantum ring that contains two electrons and is threaded by a magnetic flux B has been investigated. Localization of the electronic distribution and suppression of the Aha...The effect of an electric field E on a narrow quantum ring that contains two electrons and is threaded by a magnetic flux B has been investigated. Localization of the electronic distribution and suppression of the AharonovBohm oscillation (ABO) are found in the two-electron ring, which are similar to those found in a one-electron ring. However, the period of ABO in a two-electron ring is reduced by half compared with that in a one-electron ring. Furthermore, during the variation of B, the persistent current of the ground state may undergo a sudden change in sign. This change is associated with a singlet-triplet transition and has no counterpart in one-electron rings. For a given E, there exists a threshold of energy. When the energy of the excited state exceeds the threshold, the localization would disappear and the ABO would recover. The value of the threshold is proportional to the magnitude of E. Once the threshold is exceeded, the persistent current is much stronger than the current of the ground state at E=0.展开更多
This paper presents a simple sliding mode control strategy used for an electronic differential system for electric vehicle with two independent wheel drives. When a vehicle drives along a curved road lane, the speed o...This paper presents a simple sliding mode control strategy used for an electronic differential system for electric vehicle with two independent wheel drives. When a vehicle drives along a curved road lane, the speed of the inner wheel has to be different from that of the outer wheel in order to prevent the vehicle from vibrating and travelling an unsteady path. Because each wheel of this electrical vehicle has independent driving force, an electrical differential system is required to replace a gear differential system. However, it is difficult to analyse the nonlinear behaviour of the differential system in relation to the speed and steering angle, as well as vehicle structure. The proposed propulsion system consists of two permanent magnet synchronous machines that ensure the drive of the two back driving wheels. The proposed control structure called independent machines for speed control allows the achievement of an electronic differential which ensures the control of the vehicle behaviour on the road. It also allows to control, independently, every driving wheel to turn at different speeds in any curve. Analysis and simulation results of the proposed system are presented in this paper.展开更多
In spite of their extraordinary performance, AlGaN/GaN high electron mobility transistors (HEMTs) still lack solid reliability. Devices under accelerated DC stress tests (off-state, VDS = 0 state, and on-state step...In spite of their extraordinary performance, AlGaN/GaN high electron mobility transistors (HEMTs) still lack solid reliability. Devices under accelerated DC stress tests (off-state, VDS = 0 state, and on-state step-stress) are investigated to help us identify the degradation mechanisms of the AlGaN/GaN HEMTs. All our findings are consistent with the degradation mechanism based on crystallographic-defect formation due to the inverse piezoelectric effects in Ref. [1] (Joh J and del Alamo J A 2006 IEEE IDEM Tech. Digest p. 415). However, under the on-state condition, the devices are suffering from both inverse piezoelectric effects and hot electron effects, and so to improve the reliability of the devices both effects should be taken into consideration.展开更多
基金The Project of China Vocational Education Association(Project number:ZJS2022YB024)。
文摘This paper addresses the challenges in the teaching of electrical and electronic technology in higher vocational colleges and proposes specific countermeasures to improve teaching quality and effectiveness.The countermeasures include optimizing teaching content,emphasizing practical application and innovation,innovating teaching methods,introducing modern instructional approaches,strengthening the teaching team,enhancing teacher quality and practical expertise,upgrading experimental equipment and facilities,enriching curriculum resources,and incorporating digital teaching materials.These measures aim to cultivate high-quality skilled talents,promote social and economic development,and enhance national competitiveness.By adjusting the course structure,incorporating real-world industry cases,and fostering collaboration with enterprises,students can better understand and apply electrical and electronic technology.The introduction of project-based teaching,flipped classrooms,and multimedia technology can enhance student engagement and facilitate independent learning.Furthermore,the improvement of experimental resources and the establishment of online teaching platforms can enhance students’practical skills and provide a variety of learning resources.These measures contribute to the overall improvement of electrical and electronic technology teaching in higher vocational colleges.
文摘With the advancement of vocational education reform,education informationization,and digitalization have become the important direction of the reform of electrical and electronic teaching in high vocational colleges.In this context,intelligent product development of professional electrical and electronic teaching should also do a good job in practice and innovation,especially in actively building a digital experimental teaching platform and promoting the reform of experimental teaching mode,so that students can learn more useful knowledge and skills in the new platform,and cultivate more applied and skilled talents for society.While analyzing the problems existing in the traditional electrical and electronic experimental teaching mode,this paper analyzes the significance and practical path of the construction of electrical and electronic experimental teaching platforms in higher vocational colleges which can be of reference in future research.
文摘The teaching ability competition is a vital method for stimulating teachers’enthusiasm and enhancing their teaching skills.This approach has gained increasing attention from colleges and universities in recent years.The competition focuses on evaluating teachers’capabilities in designing and implementing lessons,encouraging the exchange of new educational ideas and high-quality teaching methods.Reforming the teaching of Electrical and Electronic Technology courses based on insights from teaching competitions can significantly improve teaching quality.This paper explores the teaching design and implementation of the Electrical and Electronic Technology course,drawing on the principles of teaching ability competitions.First,it analyzes the existing problems in teaching this course.Then,it highlights the significant benefits that teaching competitions bring to the course.Based on these insights,the paper proposes practical strategies aimed at enhancing students’interest and practical skills,thereby promoting innovative developments in teaching Electrical and Electronic Technology.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment(2017ZX07402001)the Ministry of Science and Technology of China for their financial support and the associated project is the Key Program for International S&T Cooperation Projects(No.2018YFE0124600)。
文摘Oxygen evolution reaction(OER)as the foremost stumbling block to generate cost-effective clean fuels has received extensive attention in recent years.But,it still maintains the challenge to manipulate the geometric and electronic structure during single reaction process under the same conditions.Herein,we report a simple self-template strategy to generate honeycomb-like Ni_(2)P/N,P-C hybrids with preferred electronic architecture.Experiments coupled with theoretical results revealed that the synthesized catalyst has two characteristics:firstly,the unique honeycomb-like morphology not only enables the fully utilization of catalytic active sites but also optimizes the mass/electron transportation pathway,which favor the diffusion of electrolyte to accessible active sites.Secondly,N,P-C substrate,on the one hand,largely contributes the electronic distribution near Fermi level(E_(F))thus boosting its electrical conductivity.On the other hand,the support effect result in the upshift of d-band center and electropositivity of Ni sites,which attenuates the energy barrier for the adsorption of OH~àand the formation of*OOH.In consequence,the optimized Ni_(2)P/N,P-C catalysts feature high electrocatalytic activity towards OER(a low overpotential of 252 m V to achieve10 m A cm^(-2))and 10 h long-term stability,the outstanding performance is comparable to most of transition metal catalysts.This work gives a innovative tactics for contriving original OER electrocatalysts,inspirng deeper understanding of fabricating catalysts by combining theoretical simulation and experiment design.
基金supported by the National Key Research and Development Program of China(under Grant 2020YFB1600203)National Natural Science Foundation project(under Grant 52372374).
文摘With the rapid development of autonomous vehicles,more and more functions and computing requirements have led to the continuous centralization in the topology of electrical and electronic(E/E)architectures.While certain Tier1 suppliers,such as BOSCH,have previously proposed a serial roadmap for E/E architecture development,implemented since 2015 with significant contributions to the automotive industry,lingering misconceptions and queries persist in actual engineering processes.Notably,there are concerns regarding the perspective of zone-oriented E/E architectures,characterized by zonal concentration,as successors to domain-oriented E/E architectures,known for functional concentration.Addressing these misconceptions and queries,this study introduces a novel parallel roadmap for E/E architecture development,concurrently evaluating domain-oriented and zone-oriented schemes.Furthermore,the study explores hybrid E/E architectures,amalgamating features from both paradigms.To align with the evolution of E/E architectures,networking technologies must adapt correspondingly.The networking mechanisms pivotal in E/E architecture design are comprehensively discussed.Additionally,the study delves into modeling and verification tools pertinent to E/E architecture topologies.In conclusion,the paper outlines existing challenges and unresolved queries in this domain.
文摘Equating the Rest Mass Energy of a free electron to its Rest Charge Energy we prove that the electron cannot be a dimensionless point particle because if it were dimensionless, it would contain an infinite amount of Rest Charge Energy at the location of its charge since r = 0 gives , which is clearly not possible. Since the electron has no internal structure, equating its Rest Mass Energy to its Rest Charge Energy, we calculate the electron to be a sphere of radius 4.68 × 10<sup>-</sup><sup>16</sup> meters. We calculate the Electric Field at the surface of the electron due to its charge and the Repulsive Force two electrons in proximity exert on each other.
文摘In this work, the possible structures of electron and proton have been explored. Based on the potential expressions of electron and proton, we found that the electron and proton share the similar structure inside re and rn. And within re and rn, the conventional charge concept stops working, the same charge repelling force doesn’t exist anymore and as a result, the requirement of charge conservation is automatically removed. Whereas beyond re and rn, the potential expressions of electron and proton obey the point charge potentials as we normally understand. Therefore, the conventional charge concept can be applied and the requirement of charge conservation takes effect. Furthermore, a possible mechanism for the creations of electric monopole and magnetic monopole is discussed. In addition, to compare the particle size in micro-world, the balloon criterion is proposed. By this balloon criterion, the proton is determined about 10 times bigger than electron. From the physical picture about electron and proton described above, the stabilities of electron and proton can be explained quite well.
文摘The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles.
文摘Specimens of Mugil soiuy were collected from the coastal waters of Bohai Sea in Tianjin. The gillfilaments were cut with fine scissors and soaked for 24h in a fixative consisting of 2.5% glutaralde-hyde in 0.1 mol lphosporic acid buffer. After three washes in a buffer solution the tissue was fixedin a mixture of 1% osmium tetraoxide at 4℃ for 1h. The tissue was dehydrated in graded ethandethanols and dried. The tissue was examined and photographed with an SEM at an accelerating voltage
文摘With the progress of computer technology, CAD technique is urgent needed. In this paper, we conduct numerical and theoretical analysis and research on computer aided design technique and novel pattern for electronic architectural drawing and perspective. AUTOCAD drawing soRware because of its versatility and easy entry, in engineering has broad user base, but also because of the basis of general drawing software, often cannot directly use of the existing order efficiently complete professional drawing. We modify the current pattern and introduce our proposed pattern for advancement. The experiment proves the effectiveness of the pattern. In addition, we will conduct more insightful research in the future to nolish the current anoroach.
文摘China’s largest electronic piano specialized production factory—the Shanghai Huaxin Electronics and Electrical Appliances General Factory—developed and grew up from a small loss-incurring neighborhood factory a decade ago. At present, the factory’s annual output value has exceeded RMB100 million for three years running, and sales are increasing at a rate of 30 percent per year.
文摘The waste derived from Electrical and Electronic Equipment (WEEE) is of interest now worldwide, in some countries due to the rapid technological development and in others due to technological dependence through the acquisition of second hand equipment. Therefore it is necessary to implement strategies for the sustainable management of electrical and electronic equipment at the end of its useful life. This paper presents the results of an investigation that was conducted in a city located in the Northwest of Mexico, which seeks to understand the management practices of household WEEE generators. A survey was applied to a representative sample of the population with a confidence level of 90%. Six home appliances were quantified and it was found that approximately 21% of them are disposed directly as part of the household flow of Municipal Solid Waste (MSW), while 79% are storage for a latter sale, repair or reuse. The results obtained support the need to develop evaluations and to implement possible scenarios for the sustainable management of Electrical and Electronic Waste.
文摘This paper presents the study and application of the electronic device anti-interference techniques underhigh voltage and/or heavy current electro-magnetic circumstance in power system.[
基金Fundamental Research Funds for the Central Universities(No.B230201012)National Natural Science Foundation of China(No.42104009)China Postdoctoral Science Foundation(No.2022M720988)。
文摘Total Electron Content(TEC)and electron density enhancement were observed on the day before 17 March 2015 great storm in the China Region.Observations from ground-and space-based instruments are used to investigate the temporal and spatial evolution of the pre-storm enhancement.TEC enhancement was observed from 24°N to 30°N after 10:00 UT at 105°E,110°E and 115°E longitudes on March 16.The maximum magnitude of TEC enhancement was more than 10 TECU and the maximal relative TEC enhancement exceeded 30%.Compared with geomagnetic quiet days,the electron density of Equatorial Ionization Anomaly(EIA)northern peak from Swarm A/C satellites on March 16 was larger and at higher latitudes.NmF2 enhanced during 11:30—21:00 UT at Shaoyang Station and increased by 200%at~16:00 UT.However,TEC and electron density enhancement were not accompanied by a significant change of hmF2.Most research has excluded some potential mechanisms as the main driving factors for storm-time density enhancements by establishing observational constraints.In this paper,we observed pre-storm enhancement in electron density at different altitudes and Equatorial Electrojet(EEJ)strength results derived from ground magnetometers observations suggest an enhanced eastward electric field from the E region probably played a significant role in this event.
文摘The rapid consumption of fossil fuel and increased environmental damage caused by it have given a strong impetus to the growth and development of fuelefficient vehicles. Hybrid electric vehicles (HEVs) have evolved from their inchoate state and are proving to be a promising solution to the serious existential problem posed to the planet earth. Not only do HEVs provide better fuel economy and lower emissions satisfying environmental legislations, but also they dampen the effect of rising fuel prices on consumers. HEVs combine the drive powers of an internal combustion engine and an electrical machine. The main components of HEVs are energy storage system, motor, bidirectional converter and maximum power point trackers (MPPT, in case of solar-powered HEVs). The performance of HEVs greatly depends on these components and its architecture. This paper presents an extensive review on essential components used in HEVs such as their architectures with advantages and disadvantages, choice of bidirectional converter to obtain high efficiency, combining ultracapacitor with battery to extend the battery life, traction motors’ role and their suitability for a particular application. Inclusion of photovoltaic cell in HEVs is a fairly new concept and has been discussed in detail. Various MPPT techniques used for solar-driven HEVs are also discussed in this paper with their suitability.
基金Project supported by the National Natural Science Foundation of China (Grant No 10574163), the Center of Theoretical Nuclear Physics, National Laboratory of Heavy Ion Collisions, Lanzhou, China.
文摘The effect of an electric field E on a narrow quantum ring that contains two electrons and is threaded by a magnetic flux B has been investigated. Localization of the electronic distribution and suppression of the AharonovBohm oscillation (ABO) are found in the two-electron ring, which are similar to those found in a one-electron ring. However, the period of ABO in a two-electron ring is reduced by half compared with that in a one-electron ring. Furthermore, during the variation of B, the persistent current of the ground state may undergo a sudden change in sign. This change is associated with a singlet-triplet transition and has no counterpart in one-electron rings. For a given E, there exists a threshold of energy. When the energy of the excited state exceeds the threshold, the localization would disappear and the ABO would recover. The value of the threshold is proportional to the magnitude of E. Once the threshold is exceeded, the persistent current is much stronger than the current of the ground state at E=0.
文摘This paper presents a simple sliding mode control strategy used for an electronic differential system for electric vehicle with two independent wheel drives. When a vehicle drives along a curved road lane, the speed of the inner wheel has to be different from that of the outer wheel in order to prevent the vehicle from vibrating and travelling an unsteady path. Because each wheel of this electrical vehicle has independent driving force, an electrical differential system is required to replace a gear differential system. However, it is difficult to analyse the nonlinear behaviour of the differential system in relation to the speed and steering angle, as well as vehicle structure. The proposed propulsion system consists of two permanent magnet synchronous machines that ensure the drive of the two back driving wheels. The proposed control structure called independent machines for speed control allows the achievement of an electronic differential which ensures the control of the vehicle behaviour on the road. It also allows to control, independently, every driving wheel to turn at different speeds in any curve. Analysis and simulation results of the proposed system are presented in this paper.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CBA00600)the National Natural Science Foundation of China (Grant No. 61106106)the Fundamental Research Funds for the Central Universities (Grant No. K50510250006)
文摘In spite of their extraordinary performance, AlGaN/GaN high electron mobility transistors (HEMTs) still lack solid reliability. Devices under accelerated DC stress tests (off-state, VDS = 0 state, and on-state step-stress) are investigated to help us identify the degradation mechanisms of the AlGaN/GaN HEMTs. All our findings are consistent with the degradation mechanism based on crystallographic-defect formation due to the inverse piezoelectric effects in Ref. [1] (Joh J and del Alamo J A 2006 IEEE IDEM Tech. Digest p. 415). However, under the on-state condition, the devices are suffering from both inverse piezoelectric effects and hot electron effects, and so to improve the reliability of the devices both effects should be taken into consideration.