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
The current existing problem of deep learning framework for the detection and segmentation of electrical equipment is dominantly related to low precision.Because of the reliable,safe and easy-to-operate technology pro...The current existing problem of deep learning framework for the detection and segmentation of electrical equipment is dominantly related to low precision.Because of the reliable,safe and easy-to-operate technology provided by deep learning-based video surveillance for unmanned inspection of electrical equipment,this paper uses the bottleneck attention module(BAM)attention mechanism to improve the Solov2 model and proposes a new electrical equipment segmentation mode.Firstly,the BAM attention mechanism is integrated into the feature extraction network to adaptively learn the correlation between feature channels,thereby improving the expression ability of the feature map;secondly,the weighted sum of CrossEntropy Loss and Dice loss is designed as the mask loss to improve the segmentation accuracy and robustness of the model;finally,the non-maximal suppression(NMS)algorithm to better handle the overlap problem in instance segmentation.Experimental results show that the proposed method achieves an average segmentation accuracy of mAP of 80.4% on three types of electrical equipment datasets,including transformers,insulators and voltage transformers,which improve the detection accuracy by more than 5.7% compared with the original Solov2 model.The segmentation model proposed can provide a focusing technical means for the intelligent management of power systems.展开更多
How to ensure the reliable operation of the complex and huge electrical system composed of a large number of electrical equipment in iron and steel enterprises?Combined with working experience,the author introduces fo...How to ensure the reliable operation of the complex and huge electrical system composed of a large number of electrical equipment in iron and steel enterprises?Combined with working experience,the author introduces four main factors affecting the normal operation of equipment,analyzes five main problems existing in the operation and management of electrical equipment,and puts forward corresponding improvement measures,so as to improve the management level of electrical equipment in iron and steel enterprises.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
In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the test...In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the tests of random vibrations of the cabinet system and obtain the isopleths graph of deformation and stress of the cabinet.It can confirm maximum of deformation and stress of the cabinet and position happened.Through more analysis of the frequency response curve,which can confirm harm- ful consequences random vibrations caused and weak link of the cabinet structure.The numerical simulation results are in good a- greement with the experimental results.It shows that this research provides an efficient method for the anti-seismic design and the dynamic optimization design.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
The electronic excitation temperature of a surface dielectric barrier discharge (DBD) at atmospheric pressure has been experimentally investigated by optical emission spectroscopic measurements combined with numeric...The electronic excitation temperature of a surface dielectric barrier discharge (DBD) at atmospheric pressure has been experimentally investigated by optical emission spectroscopic measurements combined with numerical simulation. Experiments have been carried out to deter- mine the spatial distribution of electric field by using FEM software and the electronic excitation temperature in discharge by calculating ratio of two relative intensities of atomic spectral lines. In this work, we choose seven Ar atomic emission lines at 415.86 nm [(3s^23p^5)5p →(3s^23p^5)4s] and 706.7 nm, 714.7 nm, 738.4 nm, 751.5 nm, 794.8 nm and 800.6 nm [(3s^23p^5)4p → (3s^23p^5)4s] to estimate the excitation temperature under a Boltzmann approximation. The average electron energy is evaluated in each discharge by using line ratio of 337.1 nm (N2(C^3Пu →B3Пg)) to 391.4 nm (N2^+(B2 ∑u^+→ ∑g^+)). Furthermore, variations of the electronic excitation tempera- ture are presented versus dielectric thickness and dielectric materials. The discharge is stable and uniform along the axial direction, and the electronic excitation temperature at the edge of the copper electrode is the largest. The corresponding average electron energy is in the range of 1.6- 5.1 eV and the electric field is in 1.7-3.2 MV/m, when the distance from copper electrode varies from 0 cm to 6 cm. Moreover, the electronic excitation temperature with a higher permittivity leads to a higher dissipated electrical power.展开更多
Electronic structures of the artificial molecule comprising two truncated pyramidal quantum dots vertically coupled and embedded in the matrix are theoretically analysed via the finite element method. When the quantum...Electronic structures of the artificial molecule comprising two truncated pyramidal quantum dots vertically coupled and embedded in the matrix are theoretically analysed via the finite element method. When the quantum dots are completely aligned, the electron energy levels decrease with the horizontally applied electric field. However, energy levels may have the maxima at non-zero electric field if the dots are staggered by a distance of several nanometers in the same direction of the electric field. In addition to shifting the energy levels, the electric field can also manipulate the electron wavefunctions confined in the quantum dots, in company with the non-perfect alignment.展开更多
With the development of electronic equipment to high accuracy, high density, high frequency, and atrocious ser- vice environment, the functional surface in this type of equipment has increasingly serious problems,
oscale devices.In the present work,we investigate the electronic structures of germanane/antimonene vdW heterostructure in response to normal strain and an external electric field by using the first-principles calcula...oscale devices.In the present work,we investigate the electronic structures of germanane/antimonene vdW heterostructure in response to normal strain and an external electric field by using the first-principles calculations based on density functional theory(DFT).The results demonstrate that the germanane/antimonene vdW heterostructure behaves as a metal in a[1,,0.6]V/A range,while it is a direct semiconductor in a[0.5,0.2]V/A range,and it is an indirect semiconduc-tor in a[0.3,1.0]V/A range.Interestingly,the band alignment of germanane/antimonene vdW heterostructure appears astype-II feature both in a[0.5,0.1]range and in a[0.3,1]V/A range,while it shows the type-I character at 0.2 V/A.In ad-dition,we find that the germanane/antimonene vdW heterostructure is an indirect semiconductor both in an in-plane biaxial strain range of[[5%,,3%]and in an in-plane biaxial strain range of[3%,5%],while it exhibits a direct semiconductor character in an in-plane biaxial strain range of[2%,2%].Furthermore,the band alignment of the germanane/antimonene vdW heterostructure changes from type-II to type-I at an in-plane biaxial strain of 3%.The adjustable electronic structure of this germanane/antimonene vdW heterostructure will pave the way for developing the nanoscale devices.展开更多
The effect of electric field on the mechanical properties and microstructure of AI-Li alloy containing Ce was investigated, and mechanism was discussed. The experimental results show that the ductility of the alloy is...The effect of electric field on the mechanical properties and microstructure of AI-Li alloy containing Ce was investigated, and mechanism was discussed. The experimental results show that the ductility of the alloy is enhanced by the electric field. The fracture features are changed and the precipitates are dispersed under the effect of the electric field. The mechanism discussion reveals that the effects of the electric field on the alloy are due to the change of the electron density in the alloy.展开更多
The low-energy electronic states and energy gaps of carbon nanocones in an electric field are studied using a single-?-band tight-binding model. The analysis considers five perfect carbon nanocones with disclination a...The low-energy electronic states and energy gaps of carbon nanocones in an electric field are studied using a single-?-band tight-binding model. The analysis considers five perfect carbon nanocones with disclination angles of 60°, 120°, 180°, 240° and 300°, respectively. The numerical results reveal that the low-energy electronic states and energy gaps of a carbon nanocones are highly sensitive to its geometric shape(i.e. the disclination angle and height), and to the direction and magnitude of an electric field. The electric field causes a strong modulation of the state energies and energy gaps of the nanocones, changes their Fermi levels, and induces zero-gap transitions. The energy-gap modulation effect becomes particularly pronounced at higher strength of the applied electric field, and is strongly related to the geometric structure of the nanocone.展开更多
High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the...High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.展开更多
The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain...The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain the best forecast dimension and using metabolism to make the model parameters adaptively change. Finally, the improved Grey Model is used to predict the fault of high voltage power supply circuit of a certain type of modern air-borne radar. The results which are computed and simulated by Matlab software show that the forecast precision of improved Grey Model is higher than that of original Grey Model.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
In this paper, the failure mechanism of electronic equipment was analysed.Aiming at the limitation of traditional maintenance modes, modern maintenance strategy was putforward on the basis of reliability-centered main...In this paper, the failure mechanism of electronic equipment was analysed.Aiming at the limitation of traditional maintenance modes, modern maintenance strategy was putforward on the basis of reliability-centered maintenance ( RCM) combined with condition-basedmaintenance ( CBM) and maintenance efficiency review (MER). A maintenance management informationsystem was constructed for electronic equipment for the purpose of failure analysis, reliabilityevaluation, and maintenance decisions such as time, mode, and plan. The best maintenance time couldbe predicted with failure analysis and reliability evaluation, which was mainly influenced byenvironmental stress. Suitable maintenance modes should be determined from equipment importance,failure aftereffect, maintenance condition, and economical power so as to ensure equipmentreliability and decrease the requirement of the maintenance source.展开更多
Sip/1199,Sip/4032 and Sip/4019 environment-friendly composites for electronic packaging applications with high volume fraction of Si particles were fabricated by squeeze-casting technology. Effects of microstructure,p...Sip/1199,Sip/4032 and Sip/4019 environment-friendly composites for electronic packaging applications with high volume fraction of Si particles were fabricated by squeeze-casting technology. Effects of microstructure,particle volume fraction,particle size,matrix alloy and heat treatment on the electrical properties of composites were discussed,and the electrical conductivity was calculated by theoretical models. It is shown that the Si/Al interfaces are clean and do not have interface reaction products. For the same matrix alloy,the electrical conductivity of composites decreases with increasing the reinforcement volume fraction. As for the same particle content,the electrical conductivity of composites decreases with increasing the alloying element content of matrix. Particle size has little effects on the electrical conductivity. Electrical conductivity of composites increases slightly after annealing treatment. The electrical conductivity of composites calculated by P.G model is consistent with the experimental results.展开更多
The life of consumer electrical and electronic(E&E)devices is relatively short,and decreasing as a result of rapid changes in equipment features and capabilities.This creates a large waste stream of obsolete E&...The life of consumer electrical and electronic(E&E)devices is relatively short,and decreasing as a result of rapid changes in equipment features and capabilities.This creates a large waste stream of obsolete E&E equipment.Even though there are conventional disposal methods for E&E waste,these methods have disadvantages from both economic and environmental viewpoints.This paper examines the existing recycling situations and collection methods of E&E waste in India and Switzerland.Questionnaire survey,interview discussions and case studies are conducted.Their E&E waste scenario and technologies applied for E&E waste are investigated.It is found that India performs better in E&E intensity per service unit and employment potentials,while Switzerland performs better in occupational hazards and emissions of toxics.Recommendations to improve the existing E&E waste recycling situations and its implications to green building are also given.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Jilin Science and Technology Development Plan Project(No.20200403075SF)Doctoral Research Start-Up Fund of Northeast Electric Power University(No.BSJXM-2018202).
文摘The current existing problem of deep learning framework for the detection and segmentation of electrical equipment is dominantly related to low precision.Because of the reliable,safe and easy-to-operate technology provided by deep learning-based video surveillance for unmanned inspection of electrical equipment,this paper uses the bottleneck attention module(BAM)attention mechanism to improve the Solov2 model and proposes a new electrical equipment segmentation mode.Firstly,the BAM attention mechanism is integrated into the feature extraction network to adaptively learn the correlation between feature channels,thereby improving the expression ability of the feature map;secondly,the weighted sum of CrossEntropy Loss and Dice loss is designed as the mask loss to improve the segmentation accuracy and robustness of the model;finally,the non-maximal suppression(NMS)algorithm to better handle the overlap problem in instance segmentation.Experimental results show that the proposed method achieves an average segmentation accuracy of mAP of 80.4% on three types of electrical equipment datasets,including transformers,insulators and voltage transformers,which improve the detection accuracy by more than 5.7% compared with the original Solov2 model.The segmentation model proposed can provide a focusing technical means for the intelligent management of power systems.
文摘How to ensure the reliable operation of the complex and huge electrical system composed of a large number of electrical equipment in iron and steel enterprises?Combined with working experience,the author introduces four main factors affecting the normal operation of equipment,analyzes five main problems existing in the operation and management of electrical equipment,and puts forward corresponding improvement measures,so as to improve the management level of electrical equipment in iron and steel enterprises.
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In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the tests of random vibrations of the cabinet system and obtain the isopleths graph of deformation and stress of the cabinet.It can confirm maximum of deformation and stress of the cabinet and position happened.Through more analysis of the frequency response curve,which can confirm harm- ful consequences random vibrations caused and weak link of the cabinet structure.The numerical simulation results are in good a- greement with the experimental results.It shows that this research provides an efficient method for the anti-seismic design and the dynamic optimization design.
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.
文摘The electronic excitation temperature of a surface dielectric barrier discharge (DBD) at atmospheric pressure has been experimentally investigated by optical emission spectroscopic measurements combined with numerical simulation. Experiments have been carried out to deter- mine the spatial distribution of electric field by using FEM software and the electronic excitation temperature in discharge by calculating ratio of two relative intensities of atomic spectral lines. In this work, we choose seven Ar atomic emission lines at 415.86 nm [(3s^23p^5)5p →(3s^23p^5)4s] and 706.7 nm, 714.7 nm, 738.4 nm, 751.5 nm, 794.8 nm and 800.6 nm [(3s^23p^5)4p → (3s^23p^5)4s] to estimate the excitation temperature under a Boltzmann approximation. The average electron energy is evaluated in each discharge by using line ratio of 337.1 nm (N2(C^3Пu →B3Пg)) to 391.4 nm (N2^+(B2 ∑u^+→ ∑g^+)). Furthermore, variations of the electronic excitation tempera- ture are presented versus dielectric thickness and dielectric materials. The discharge is stable and uniform along the axial direction, and the electronic excitation temperature at the edge of the copper electrode is the largest. The corresponding average electron energy is in the range of 1.6- 5.1 eV and the electric field is in 1.7-3.2 MV/m, when the distance from copper electrode varies from 0 cm to 6 cm. Moreover, the electronic excitation temperature with a higher permittivity leads to a higher dissipated electrical power.
基金supported by the National High Technology Research and Development Program of China (Grant No. 2009AA03Z405)the National Natural Science Foundation of China (Grant Nos. 60908028 and 60971068)the Fundamental Research Funds for the Central Universities (Grant No. BUPT2009RC0411)
文摘Electronic structures of the artificial molecule comprising two truncated pyramidal quantum dots vertically coupled and embedded in the matrix are theoretically analysed via the finite element method. When the quantum dots are completely aligned, the electron energy levels decrease with the horizontally applied electric field. However, energy levels may have the maxima at non-zero electric field if the dots are staggered by a distance of several nanometers in the same direction of the electric field. In addition to shifting the energy levels, the electric field can also manipulate the electron wavefunctions confined in the quantum dots, in company with the non-perfect alignment.
文摘With the development of electronic equipment to high accuracy, high density, high frequency, and atrocious ser- vice environment, the functional surface in this type of equipment has increasingly serious problems,
基金Project supported by the National Natural Science Foundation of China(Grant No.11864011).
文摘oscale devices.In the present work,we investigate the electronic structures of germanane/antimonene vdW heterostructure in response to normal strain and an external electric field by using the first-principles calculations based on density functional theory(DFT).The results demonstrate that the germanane/antimonene vdW heterostructure behaves as a metal in a[1,,0.6]V/A range,while it is a direct semiconductor in a[0.5,0.2]V/A range,and it is an indirect semiconduc-tor in a[0.3,1.0]V/A range.Interestingly,the band alignment of germanane/antimonene vdW heterostructure appears astype-II feature both in a[0.5,0.1]range and in a[0.3,1]V/A range,while it shows the type-I character at 0.2 V/A.In ad-dition,we find that the germanane/antimonene vdW heterostructure is an indirect semiconductor both in an in-plane biaxial strain range of[[5%,,3%]and in an in-plane biaxial strain range of[3%,5%],while it exhibits a direct semiconductor character in an in-plane biaxial strain range of[2%,2%].Furthermore,the band alignment of the germanane/antimonene vdW heterostructure changes from type-II to type-I at an in-plane biaxial strain of 3%.The adjustable electronic structure of this germanane/antimonene vdW heterostructure will pave the way for developing the nanoscale devices.
文摘The effect of electric field on the mechanical properties and microstructure of AI-Li alloy containing Ce was investigated, and mechanism was discussed. The experimental results show that the ductility of the alloy is enhanced by the electric field. The fracture features are changed and the precipitates are dispersed under the effect of the electric field. The mechanism discussion reveals that the effects of the electric field on the alloy are due to the change of the electron density in the alloy.
基金supported in part by the National Science Council of Taiwan under Grant Nos.NSC 96-2221-E-492-007-MY3 and NSC 98-2221-E-006-131-MY3National Center for Theoretical Science(NCTS)in Taiwan
文摘The low-energy electronic states and energy gaps of carbon nanocones in an electric field are studied using a single-?-band tight-binding model. The analysis considers five perfect carbon nanocones with disclination angles of 60°, 120°, 180°, 240° and 300°, respectively. The numerical results reveal that the low-energy electronic states and energy gaps of a carbon nanocones are highly sensitive to its geometric shape(i.e. the disclination angle and height), and to the direction and magnitude of an electric field. The electric field causes a strong modulation of the state energies and energy gaps of the nanocones, changes their Fermi levels, and induces zero-gap transitions. The energy-gap modulation effect becomes particularly pronounced at higher strength of the applied electric field, and is strongly related to the geometric structure of the nanocone.
文摘High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.
文摘The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain the best forecast dimension and using metabolism to make the model parameters adaptively change. Finally, the improved Grey Model is used to predict the fault of high voltage power supply circuit of a certain type of modern air-borne radar. The results which are computed and simulated by Matlab software show that the forecast precision of improved Grey Model is higher than that of original Grey Model.
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In this paper, the failure mechanism of electronic equipment was analysed.Aiming at the limitation of traditional maintenance modes, modern maintenance strategy was putforward on the basis of reliability-centered maintenance ( RCM) combined with condition-basedmaintenance ( CBM) and maintenance efficiency review (MER). A maintenance management informationsystem was constructed for electronic equipment for the purpose of failure analysis, reliabilityevaluation, and maintenance decisions such as time, mode, and plan. The best maintenance time couldbe predicted with failure analysis and reliability evaluation, which was mainly influenced byenvironmental stress. Suitable maintenance modes should be determined from equipment importance,failure aftereffect, maintenance condition, and economical power so as to ensure equipmentreliability and decrease the requirement of the maintenance source.
基金Project (2003AA305110) supported by the Hi-tech Research and Development Program of ChinaProject (2005AA5CG041) supported by the Key-tech Research and Development Program of Harbin, China
文摘Sip/1199,Sip/4032 and Sip/4019 environment-friendly composites for electronic packaging applications with high volume fraction of Si particles were fabricated by squeeze-casting technology. Effects of microstructure,particle volume fraction,particle size,matrix alloy and heat treatment on the electrical properties of composites were discussed,and the electrical conductivity was calculated by theoretical models. It is shown that the Si/Al interfaces are clean and do not have interface reaction products. For the same matrix alloy,the electrical conductivity of composites decreases with increasing the reinforcement volume fraction. As for the same particle content,the electrical conductivity of composites decreases with increasing the alloying element content of matrix. Particle size has little effects on the electrical conductivity. Electrical conductivity of composites increases slightly after annealing treatment. The electrical conductivity of composites calculated by P.G model is consistent with the experimental results.
文摘The life of consumer electrical and electronic(E&E)devices is relatively short,and decreasing as a result of rapid changes in equipment features and capabilities.This creates a large waste stream of obsolete E&E equipment.Even though there are conventional disposal methods for E&E waste,these methods have disadvantages from both economic and environmental viewpoints.This paper examines the existing recycling situations and collection methods of E&E waste in India and Switzerland.Questionnaire survey,interview discussions and case studies are conducted.Their E&E waste scenario and technologies applied for E&E waste are investigated.It is found that India performs better in E&E intensity per service unit and employment potentials,while Switzerland performs better in occupational hazards and emissions of toxics.Recommendations to improve the existing E&E waste recycling situations and its implications to green building are also given.