A novel technique to fabricate ultra deep high aspect ratio electrical isolation trenches with DRIE and dielectric refill is presented.The relationship between trench profile and DRIE parameters is discussed.By optimi...A novel technique to fabricate ultra deep high aspect ratio electrical isolation trenches with DRIE and dielectric refill is presented.The relationship between trench profile and DRIE parameters is discussed.By optimizing DRIE parameters and RIE etching the trenches’ opening,the ideal trench profile is obtained to ensure that the trenches are fully refilled without voids.The electrical isolation trenches are 5μm wide and 92μm deep with 0.5μm thick oxide layers on the sidewall as isolation material.The measured I-V result shows that the trench structure has good electrical isolation performance:the average resistance in the range of 0~100V is more than 10 11Ω and no breakdown appears under 100V.This isolation trench structure has been used in fabrication of the bulk integrated micromachined gyroscope,which shows high performance.展开更多
The rapid development of intelligent technology has led to its introduction into the field of electrical lighting in buildings.It provides more technical support for system design,use,and management,and creates a comf...The rapid development of intelligent technology has led to its introduction into the field of electrical lighting in buildings.It provides more technical support for system design,use,and management,and creates a comfortable and safe living environment.The adoption of intelligent technology enables the creation of an intelligent management system,where controllers and sensors are used to adjust the light source within the building,monitor and manage the lighting system in real time,monitor the energy consumption and safety of the system,and achieve the goal of energy saving and emission reduction.This paper briefly discusses the application and significance of intelligent technology in electrical lighting and puts forward design ideas to optimize electrical lighting and measures for lighting system management.展开更多
Absorption and carrier transport behavior plays an important role in the light-to-electricity conversion process, which is difficult to characterize. Here we develop a method to visualize such a conversion process in ...Absorption and carrier transport behavior plays an important role in the light-to-electricity conversion process, which is difficult to characterize. Here we develop a method to visualize such a conversion process in the InGaN/GaN multiquantum wells embedded in a p-n junction. Under non-resonant absorption conditions, a photocurrent was generated and the photoluminescence intensity decayed by more than 70% when the p-n junction out-circuit was switched from open to short. However, when the excitation photon energy decreased to the resonant absorption edge, the photocurrent dropped drastically and the photoluminescence under open and short circuit conditions showed similar intensity. These results indicate that the escaping of the photo-generated carriers from the quantum wells is closely related to the excitation photon energy.展开更多
The significance of research of water system is demonstrated by the experiments and statistical data. Some physical and chemical properties of water system affected by various factors in the nature are given. It also ...The significance of research of water system is demonstrated by the experiments and statistical data. Some physical and chemical properties of water system affected by various factors in the nature are given. It also points out that further research of the effect on extremely complicated water system caused by electricity, magnetic field, sound and light now becomes an important research subject.展开更多
Atmospheric electricity is composed of a wide range of electric phenomena in the troposphere, strato- sphere, and even lower ionosphere. Research progress on atmospheric electricity in the past 5 years in China are br...Atmospheric electricity is composed of a wide range of electric phenomena in the troposphere, strato- sphere, and even lower ionosphere. Research progress on atmospheric electricity in the past 5 years in China are briefly reviewed here. This research area has been greatly expanded through rocket-triggered lightning experiments and the increased use of high spatio-temporal resolution techniques for the detection and location of lightning. The main results described in this review are summarized in the following five aspects: (1) processes and parameters inferred from rocket-triggered lightning, (2) lightning physics and ef- fects (observations and theoretical study), (3) lightning activities associated with different thunderstorms, (4) charge structure of thunderstorms (observations and simulation), and (5) the VHF/UHF lightning location techniques and discharge channel mapping.展开更多
In order to investigate their electrical characteristics, high-voltage light-emitting-diodes (HV-LEDs) each contain- ing four cells in series are fabricated. The electrical parameters including varying voltage and p...In order to investigate their electrical characteristics, high-voltage light-emitting-diodes (HV-LEDs) each contain- ing four cells in series are fabricated. The electrical parameters including varying voltage and parasitic effect are studied. It is shown that the ideality factors (IFs) of the HV-LEDs with different numbers of cells are 1.6, 3.4, 4.7, and 6.4. IF increases linearly with the number of cells increasing. Moreover, the performance of the HV-LED with failure cells is examined, The analysis indicates that the failure cell has a parallel resistance which induces the leakage of the failure cell. The series resistance of the failure cell is 76.8 Ω, while that of the normal cell is 21.3 Ω. The scanning electron microscope (SEM) image indicates that different metal layers do not contact well. It is hard to deposit the metal layers in the deep isolation trenches. The fabrication process of HV-LEDs needs to be optimized.展开更多
The degradation mechanism of GaN-based near-ultraviolet(NUV,320-400 nm)light emitting diodes(LEDs)with low-indium content under electrical stress is studied from the aspect of defects.A decrease in the optical power a...The degradation mechanism of GaN-based near-ultraviolet(NUV,320-400 nm)light emitting diodes(LEDs)with low-indium content under electrical stress is studied from the aspect of defects.A decrease in the optical power and an increase in the leakage current are observed after electrical stress.The defect behaviors are characterized using deep level transient spectroscopy(DLTS)measurement under different filling pulse widths.After stress,the concentration of defects with the energy level of 0.47-0.56 eV increases,accompanied by decrease in the concentration of 0.72-0.84 eV defects.Combing the defect energy level with the increased yellow luminescence in photoluminescence spectra,the device degradation can be attributed to the activation of the gallium vacancy and oxygen related complex defect along dislocation,which was previously passivated with hydrogen.This study reveals the evolution process of defects under electrical stress and their spatial location,laying a foundation for manufacture of GaN-based NUV LEDs with high reliability.展开更多
The superior vena cava (SVC) is known to be a potential source of focal atrial tachycardias. Not uncommonly these tachycardias trigger atrial fibrillation or flutter. Focal ablation is safe and effective in eliminatin...The superior vena cava (SVC) is known to be a potential source of focal atrial tachycardias. Not uncommonly these tachycardias trigger atrial fibrillation or flutter. Focal ablation is safe and effective in eliminating arrhythmogenic foci within the SVC. We present the case of a patient with focal atrial tachycardia arising from the SVC. During presumably focal ablation inadvertent electrical isolation of the SVC from the right atrium was achieved, with restoration of sinus rhythm in the atria and persistence of the tachycardia within the SVC.展开更多
In Brazil and various regions globally, the initiation of landslides is frequently associated with rainfall;yet the spatial arrangement of geological structures and stratification considerably influences landslide occ...In Brazil and various regions globally, the initiation of landslides is frequently associated with rainfall;yet the spatial arrangement of geological structures and stratification considerably influences landslide occurrences. The multifaceted nature of these influences makes the surveillance of mass movements a highly intricate task, requiring an understanding of numerous interdependent variables. Recent years have seen an emergence in scholarly research aimed at integrating geophysical and geotechnical methodologies. The conjoint examination of geophysical and geotechnical data offers an enhanced perspective into subsurface structures. Within this work, a methodology is proposed for the synchronous analysis of electrical resistivity geophysical data and geotechnical data, specifically those extracted from the Light Dynamic Penetrometer (DPL) and Standard Penetration Test (SPT). This study involved a linear fitting process to correlate resistivity with N10/SPT N-values from DPL/SPT soundings, culminating in a 2D profile of N10/SPT N-values predicated on electrical profiles. The findings of this research furnish invaluable insights into slope stability by allowing for a two-dimensional representation of penetration resistance properties. Through the synthesis of geophysical and geotechnical data, this project aims to augment the comprehension of subsurface conditions, with potential implications for refining landslide risk evaluations. This endeavor offers insight into the formulation of more effective and precise slope management protocols and disaster prevention strategies.展开更多
A novel super-junction lateral double-diffused metal-oxide semiconductor (SJ-LDMOS) with a partial lightly doped P pillar (PD) is proposed. Firstly, the reduction in the partial P pillar charges ensures the charge...A novel super-junction lateral double-diffused metal-oxide semiconductor (SJ-LDMOS) with a partial lightly doped P pillar (PD) is proposed. Firstly, the reduction in the partial P pillar charges ensures the charge balance and suppresses the substrate-assisted depletion effect. Secondly, the new electric field peak produced by the P/P junction modulates the surface electric field distribution. Both of these result in a high breakdown voltage (BV). In addition, due to the same conduction paths, the specific on-resistance (Ron,sp) of the PD SJ-LDMOS is approximately identical to the conventional SJ-LDMOS. Simulation results indicate that the average value of the surface lateral electric field of the PD SJ-LDMOS reaches 20 V/μm at a 15 μm drift length, resulting in a BV of 300 V.展开更多
Nanoqueous phase liquid(NAPL) simulator is a powerful and popular mathematical model for modeling the flow and transport of non-aqueous phase liquids in subsurface,but the testing of its feasibility under water table ...Nanoqueous phase liquid(NAPL) simulator is a powerful and popular mathematical model for modeling the flow and transport of non-aqueous phase liquids in subsurface,but the testing of its feasibility under water table fluctuation has received insufficient attention.The feature in a column test was tested through two cycles of water table fluctuation.The sandy medium in the column was initially saturated,and each cycle of water table fluctuation consisted of one water table falling and one rising,resulting in a drainage and an imbibition of the medium,respectively.It was found that the difference between the simulated and measured results in the first drainage of the column test was minor.However,with the propagation of the water table fluctuations,the simulation errors increased,and the simulation accuracy was not acceptable except for the first drainage in the two fluctuation cycles.The main reason was proved to be the estimation method of residual saturation used in this simulator.Also,based on the column tests,it was assumed that the resulting residual saturation from an incomplete imbibition process was a constant,with a value equal to that of the residual value resulting from the main imbibition process.The results obtained after modifying NAPL simulator with this assumption were found to be more accurate in the first cycle of water table fluctuation,but this accuracy decreased rapidly in the second one.It is concluded that NAPL simulator is not adequate in the case of LNAPL migration under water table fluctuation in sandy medium,unless a feasible assumption to estimate residual saturation is put forward.展开更多
It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentra...It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>展开更多
The autonomous navigation of an electric vehicle requires the implementation of a number of sensors and actuators intended to inform it about his environment or his position and velocity and deliver necessary inputs. ...The autonomous navigation of an electric vehicle requires the implementation of a number of sensors and actuators intended to inform it about his environment or his position and velocity and deliver necessary inputs. That's why it is important to detect and locate sensor and actuator faults as soon as possible to enable the operator to run the vehicle in degraded mode or use the fault tolerant control system if it exists. The main purpose of this paper deals with sensors or actuators faults diagnosis of autonomous vehicle. A diagnosis method using a nonlinear model of the vehicle is developed. Nonlinear state space model of the autonomous electric vehicle is used with the method of nonlinear analytical redundancy to detect and to isolate faults occurred on sensors or actuators. Computer simulations are carried out to verify the effectiveness of the method.展开更多
The efficiency of a silicon solar cell is directly linked to the quantity of carrier photogenerated in its base. It increases with the increase of the quantity of carrier in the base of the solar cell. The carrier den...The efficiency of a silicon solar cell is directly linked to the quantity of carrier photogenerated in its base. It increases with the increase of the quantity of carrier in the base of the solar cell. The carrier density in the base of the solar cell increases with the increase of the flux of photons that crosses the solar cell. One of the methods used to increase the flux of photon on the illuminated side of the solar cell is the intensification of the illumination light. However, the intensification of the light come with the increase of the energy released by thermalization, the collision between carriers, their braking due to the carriers concentration gradient electric field which lead to increase the temperature in the base of the solar cell. This work presents a 3-D study, of the effect of the temperature on the electronic parameters of a polycrystalline silicon solar under intense light illumination. The electronic parameters on which we analyze the temperature effect are:?the mobility of solar cell carriers?(electrons and holes),?their diffusion coefficient, their diffusion length and their distribution in the bulk of the base. To study the effect of the temperature on electronic parameters, we take into account, the dependence of carriers (electrons and holes) mobility with the temperature (μn,(T)?μp(T)). Then, the resolution of the continuity equation,which is a function of the carriers gradient electric field and the carriers mobility,?leads to the expressions of?the diffusion coefficient, the diffusion length, and the density of carriers which are function of the temperature. Then, we studied the effects of the temperature on the diffusion parameters in order to explain their effect on the behavior the carriers distribution in intermediate, short circuit and open circuit operating modes at several positions in the base depth. It appears through this study that the diffusion coefficient and the diffusion length decrease with the increase of the temperature. We observe also that with the increase of the temperature, the density of carriers in the base of the solar cell in short circuit and open voltage operating modes increases. In intermediate operating mode, the density of carriers increases also with the temperature but it is function of the base depth.展开更多
The principle of miniature isolated solid-state encapsulation technology of high-temperature pressure sensor and the structure of packaging are discussed, including static electricity bonding, stainless steel diaphrag...The principle of miniature isolated solid-state encapsulation technology of high-temperature pressure sensor and the structure of packaging are discussed, including static electricity bonding, stainless steel diaphragm selection and rippled design, laser welding, silicon oil infilling, isolation and other techniques used in sensor packaging, which can affect the performance of the sensor. By adopting stainless steel diaphragm and high-temperature silicon oil as isolation materials, not only the encapsulation of the sensor is as small as 15 mm in diameter and under 1 mA drive, its full range output is 72 mV and zero stability is 0.48% F.S/mon, but also the reliability of the sensor is improved and its application is widely broadened.展开更多
Benefiting from the induced image charge on film surface,the nanoparticle aggregating on metal exhibits interesting optical properties.In this work,a linear metal nanoparticle trimer on metal film system has been inve...Benefiting from the induced image charge on film surface,the nanoparticle aggregating on metal exhibits interesting optical properties.In this work,a linear metal nanoparticle trimer on metal film system has been investigated to explore the novel optical phenomenon.Both the electric field and surface charge distributions demonstrate the light is focused on film greatly by the nanoparticles at two sides,which could be strongly modulated by the wavelength of incident light.And the influence of nanoparticle in middle on this light focusing ability has also been studied here,which is explained by the plasmon hybridization theory.Our finding about light focusing in nanoparticle aggregating on metal film not only enlarges the novel phenomenon of surface plasmon but also has great application prospect in the field of surface-enhanced spectra,surface catalysis,solar cells,water splitting,etc.展开更多
With brief statements of the linear electro-optical modulation and magnetooptical modulation, using the method of resultant of optical amplitude vectors and the methed of Jones matrix, formulas for intensity of transm...With brief statements of the linear electro-optical modulation and magnetooptical modulation, using the method of resultant of optical amplitude vectors and the methed of Jones matrix, formulas for intensity of transmitted light through the optical analyzer of various composition of electro-optical effect with magneto-optical effect are derived. The results show that the output beam from the analyzer carries information on current (or magnetic field), voltage (or electric field), active power and apparent power. When the light beam transmitted through the analyzer are transformed into electric signals, three kinds of information are included: the DC term corresponding to an active power, the term with frequency ω(50 Hz) corresponding to current or voltage, and the term with frequency 2ω(100 Hz) corresponding to an apparnt power.So, we can use the electric filter circuit to pick out the DC component for measuring active power; to pick out the component with frequency ω(50 Hz) for measuring current or voltage; and to pick out the component with frequency 2ω(100 Hz) for measuring apparent power. The paper discusses what quantities are measured when the analyzer is set on certain definite values, and ponts out the optimum selection for various measurements.展开更多
As the quality of power LED improves and the cost of power LED reduces, semiconductor lighting will replace incandescent and fluorescent lighting gradually, causing another revolution on the lighting history. And its ...As the quality of power LED improves and the cost of power LED reduces, semiconductor lighting will replace incandescent and fluorescent lighting gradually, causing another revolution on the lighting history. And its driving solution has been greatly accelerated. Based on the white power LED I-V characteristics and the application ambiance, proposed is a new LED lighting solution, suiting indoor and outdoor illumination. According to the test results, the design is optimized, and the electrical efficiency is 95% and the output current deviation is 13.0%.展开更多
文摘A novel technique to fabricate ultra deep high aspect ratio electrical isolation trenches with DRIE and dielectric refill is presented.The relationship between trench profile and DRIE parameters is discussed.By optimizing DRIE parameters and RIE etching the trenches’ opening,the ideal trench profile is obtained to ensure that the trenches are fully refilled without voids.The electrical isolation trenches are 5μm wide and 92μm deep with 0.5μm thick oxide layers on the sidewall as isolation material.The measured I-V result shows that the trench structure has good electrical isolation performance:the average resistance in the range of 0~100V is more than 10 11Ω and no breakdown appears under 100V.This isolation trench structure has been used in fabrication of the bulk integrated micromachined gyroscope,which shows high performance.
文摘The rapid development of intelligent technology has led to its introduction into the field of electrical lighting in buildings.It provides more technical support for system design,use,and management,and creates a comfortable and safe living environment.The adoption of intelligent technology enables the creation of an intelligent management system,where controllers and sensors are used to adjust the light source within the building,monitor and manage the lighting system in real time,monitor the energy consumption and safety of the system,and achieve the goal of energy saving and emission reduction.This paper briefly discusses the application and significance of intelligent technology in electrical lighting and puts forward design ideas to optimize electrical lighting and measures for lighting system management.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFB0400302 and 2016YFB0400603)the National Natural Science Foundation of China(Grant Nos.11574362,61210014,and 11374340)the Innovative Clean-Energy Research and Application Program of Beijing Municipal Science and Technology Commission,China(Grant No.Z151100003515001)
文摘Absorption and carrier transport behavior plays an important role in the light-to-electricity conversion process, which is difficult to characterize. Here we develop a method to visualize such a conversion process in the InGaN/GaN multiquantum wells embedded in a p-n junction. Under non-resonant absorption conditions, a photocurrent was generated and the photoluminescence intensity decayed by more than 70% when the p-n junction out-circuit was switched from open to short. However, when the excitation photon energy decreased to the resonant absorption edge, the photocurrent dropped drastically and the photoluminescence under open and short circuit conditions showed similar intensity. These results indicate that the escaping of the photo-generated carriers from the quantum wells is closely related to the excitation photon energy.
文摘The significance of research of water system is demonstrated by the experiments and statistical data. Some physical and chemical properties of water system affected by various factors in the nature are given. It also points out that further research of the effect on extremely complicated water system caused by electricity, magnetic field, sound and light now becomes an important research subject.
基金supported by National Natural Science Foundation of China (Grant No.40930949)the One Hundred Person Project of the Chinese Academy of Sciences
文摘Atmospheric electricity is composed of a wide range of electric phenomena in the troposphere, strato- sphere, and even lower ionosphere. Research progress on atmospheric electricity in the past 5 years in China are briefly reviewed here. This research area has been greatly expanded through rocket-triggered lightning experiments and the increased use of high spatio-temporal resolution techniques for the detection and location of lightning. The main results described in this review are summarized in the following five aspects: (1) processes and parameters inferred from rocket-triggered lightning, (2) lightning physics and ef- fects (observations and theoretical study), (3) lightning activities associated with different thunderstorms, (4) charge structure of thunderstorms (observations and simulation), and (5) the VHF/UHF lightning location techniques and discharge channel mapping.
基金Project supported by the National Natural Science Foundation of China(Grant No.11002013201102)the National Key Technology R & D Program of China(Grant No.2011BAE01B14)
文摘In order to investigate their electrical characteristics, high-voltage light-emitting-diodes (HV-LEDs) each contain- ing four cells in series are fabricated. The electrical parameters including varying voltage and parasitic effect are studied. It is shown that the ideality factors (IFs) of the HV-LEDs with different numbers of cells are 1.6, 3.4, 4.7, and 6.4. IF increases linearly with the number of cells increasing. Moreover, the performance of the HV-LED with failure cells is examined, The analysis indicates that the failure cell has a parallel resistance which induces the leakage of the failure cell. The series resistance of the failure cell is 76.8 Ω, while that of the normal cell is 21.3 Ω. The scanning electron microscope (SEM) image indicates that different metal layers do not contact well. It is hard to deposit the metal layers in the deep isolation trenches. The fabrication process of HV-LEDs needs to be optimized.
基金supported by the National Natural Science Foundation of China(Grant Nos.62104180,61974115,11690042,61634005,61974111,12035019,and 61904142)the Fundamental Research Funds for the Central Universities(Grant No.XJS221106)the Key Research and Development Program of Shaanxi,China(Grant No.2020ZDLGY03-05)。
文摘The degradation mechanism of GaN-based near-ultraviolet(NUV,320-400 nm)light emitting diodes(LEDs)with low-indium content under electrical stress is studied from the aspect of defects.A decrease in the optical power and an increase in the leakage current are observed after electrical stress.The defect behaviors are characterized using deep level transient spectroscopy(DLTS)measurement under different filling pulse widths.After stress,the concentration of defects with the energy level of 0.47-0.56 eV increases,accompanied by decrease in the concentration of 0.72-0.84 eV defects.Combing the defect energy level with the increased yellow luminescence in photoluminescence spectra,the device degradation can be attributed to the activation of the gallium vacancy and oxygen related complex defect along dislocation,which was previously passivated with hydrogen.This study reveals the evolution process of defects under electrical stress and their spatial location,laying a foundation for manufacture of GaN-based NUV LEDs with high reliability.
文摘The superior vena cava (SVC) is known to be a potential source of focal atrial tachycardias. Not uncommonly these tachycardias trigger atrial fibrillation or flutter. Focal ablation is safe and effective in eliminating arrhythmogenic foci within the SVC. We present the case of a patient with focal atrial tachycardia arising from the SVC. During presumably focal ablation inadvertent electrical isolation of the SVC from the right atrium was achieved, with restoration of sinus rhythm in the atria and persistence of the tachycardia within the SVC.
文摘In Brazil and various regions globally, the initiation of landslides is frequently associated with rainfall;yet the spatial arrangement of geological structures and stratification considerably influences landslide occurrences. The multifaceted nature of these influences makes the surveillance of mass movements a highly intricate task, requiring an understanding of numerous interdependent variables. Recent years have seen an emergence in scholarly research aimed at integrating geophysical and geotechnical methodologies. The conjoint examination of geophysical and geotechnical data offers an enhanced perspective into subsurface structures. Within this work, a methodology is proposed for the synchronous analysis of electrical resistivity geophysical data and geotechnical data, specifically those extracted from the Light Dynamic Penetrometer (DPL) and Standard Penetration Test (SPT). This study involved a linear fitting process to correlate resistivity with N10/SPT N-values from DPL/SPT soundings, culminating in a 2D profile of N10/SPT N-values predicated on electrical profiles. The findings of this research furnish invaluable insights into slope stability by allowing for a two-dimensional representation of penetration resistance properties. Through the synthesis of geophysical and geotechnical data, this project aims to augment the comprehension of subsurface conditions, with potential implications for refining landslide risk evaluations. This endeavor offers insight into the formulation of more effective and precise slope management protocols and disaster prevention strategies.
基金supported by the National Science and Technology Major Project of the Ministry of Science and Technology of China (Grant No. 2010ZX02201)the National Natural Science Foundation of China (Grant No. 61176069)the National Defense Pre-Research of China (Grant No. 51308020304)
文摘A novel super-junction lateral double-diffused metal-oxide semiconductor (SJ-LDMOS) with a partial lightly doped P pillar (PD) is proposed. Firstly, the reduction in the partial P pillar charges ensures the charge balance and suppresses the substrate-assisted depletion effect. Secondly, the new electric field peak produced by the P/P junction modulates the surface electric field distribution. Both of these result in a high breakdown voltage (BV). In addition, due to the same conduction paths, the specific on-resistance (Ron,sp) of the PD SJ-LDMOS is approximately identical to the conventional SJ-LDMOS. Simulation results indicate that the average value of the surface lateral electric field of the PD SJ-LDMOS reaches 20 V/μm at a 15 μm drift length, resulting in a BV of 300 V.
基金Project(41072182)supported by the National Natural Science Foundation of ChinaProject(2010Z1-E101)supported by Science and Technology Program of Guangzhou City,China+1 种基金Project(20100103)supported by Science and Technology Program of Daya Bay,Huizhou City,ChinaProject(2012A030700008)supported by the Science and Technology Planning Program of Guangdong Province,China
文摘Nanoqueous phase liquid(NAPL) simulator is a powerful and popular mathematical model for modeling the flow and transport of non-aqueous phase liquids in subsurface,but the testing of its feasibility under water table fluctuation has received insufficient attention.The feature in a column test was tested through two cycles of water table fluctuation.The sandy medium in the column was initially saturated,and each cycle of water table fluctuation consisted of one water table falling and one rising,resulting in a drainage and an imbibition of the medium,respectively.It was found that the difference between the simulated and measured results in the first drainage of the column test was minor.However,with the propagation of the water table fluctuations,the simulation errors increased,and the simulation accuracy was not acceptable except for the first drainage in the two fluctuation cycles.The main reason was proved to be the estimation method of residual saturation used in this simulator.Also,based on the column tests,it was assumed that the resulting residual saturation from an incomplete imbibition process was a constant,with a value equal to that of the residual value resulting from the main imbibition process.The results obtained after modifying NAPL simulator with this assumption were found to be more accurate in the first cycle of water table fluctuation,but this accuracy decreased rapidly in the second one.It is concluded that NAPL simulator is not adequate in the case of LNAPL migration under water table fluctuation in sandy medium,unless a feasible assumption to estimate residual saturation is put forward.
文摘It is well known that temperature acts negatively on practically all the parameters of photovoltaic solar cells. Also, the solar cells which are subjected to particularly very high temperatures are the light concentration solar cells and are used in light concentration photovoltaic systems (<i><span style="font-family:Verdana;">CPV</span></i><span style="font-family:Verdana;">). In fact, the significant heating of these solar cells is due to the concentration of the solar flux which arrives on them. Light concentration solar cells appear as solar cells under strong influences of heating and temperature. It is therefore necessary to take into account temperature effect on light concentration solar cells performances in order to obtain realistic results. </span><span style="font-family:""><span style="font-family:Verdana;">This one-dimensional study of a crystalline silicon solar cell under light concentration takes into account electrons concentration gradient electric field in the determination of the continuity equation of minority carriers in the base. To determine excess minority carrier’s density, the effects of temperature on the diffusion and mobility of electrons and holes, on the intrinsic concentration of electrons, on carrier’s generation rate as well as on width of band gap have also been taken into account. The results show that an increase of temperature improves diffusion parameters and leads to an increase of the short-circuit photocurrent density. However, an increase of temperature leads to a significant decrease in open-circuit photovoltage, maximum electric power and conversion efficiency. The results also show that the operating point and the maximum power point (</span><i><span style="font-family:Verdana;">MPP</span></i><span style="font-family:Verdana;">) moves to the open circuit when the cell temperature increases.</span></span>
文摘The autonomous navigation of an electric vehicle requires the implementation of a number of sensors and actuators intended to inform it about his environment or his position and velocity and deliver necessary inputs. That's why it is important to detect and locate sensor and actuator faults as soon as possible to enable the operator to run the vehicle in degraded mode or use the fault tolerant control system if it exists. The main purpose of this paper deals with sensors or actuators faults diagnosis of autonomous vehicle. A diagnosis method using a nonlinear model of the vehicle is developed. Nonlinear state space model of the autonomous electric vehicle is used with the method of nonlinear analytical redundancy to detect and to isolate faults occurred on sensors or actuators. Computer simulations are carried out to verify the effectiveness of the method.
文摘The efficiency of a silicon solar cell is directly linked to the quantity of carrier photogenerated in its base. It increases with the increase of the quantity of carrier in the base of the solar cell. The carrier density in the base of the solar cell increases with the increase of the flux of photons that crosses the solar cell. One of the methods used to increase the flux of photon on the illuminated side of the solar cell is the intensification of the illumination light. However, the intensification of the light come with the increase of the energy released by thermalization, the collision between carriers, their braking due to the carriers concentration gradient electric field which lead to increase the temperature in the base of the solar cell. This work presents a 3-D study, of the effect of the temperature on the electronic parameters of a polycrystalline silicon solar under intense light illumination. The electronic parameters on which we analyze the temperature effect are:?the mobility of solar cell carriers?(electrons and holes),?their diffusion coefficient, their diffusion length and their distribution in the bulk of the base. To study the effect of the temperature on electronic parameters, we take into account, the dependence of carriers (electrons and holes) mobility with the temperature (μn,(T)?μp(T)). Then, the resolution of the continuity equation,which is a function of the carriers gradient electric field and the carriers mobility,?leads to the expressions of?the diffusion coefficient, the diffusion length, and the density of carriers which are function of the temperature. Then, we studied the effects of the temperature on the diffusion parameters in order to explain their effect on the behavior the carriers distribution in intermediate, short circuit and open circuit operating modes at several positions in the base depth. It appears through this study that the diffusion coefficient and the diffusion length decrease with the increase of the temperature. We observe also that with the increase of the temperature, the density of carriers in the base of the solar cell in short circuit and open voltage operating modes increases. In intermediate operating mode, the density of carriers increases also with the temperature but it is function of the base depth.
文摘The principle of miniature isolated solid-state encapsulation technology of high-temperature pressure sensor and the structure of packaging are discussed, including static electricity bonding, stainless steel diaphragm selection and rippled design, laser welding, silicon oil infilling, isolation and other techniques used in sensor packaging, which can affect the performance of the sensor. By adopting stainless steel diaphragm and high-temperature silicon oil as isolation materials, not only the encapsulation of the sensor is as small as 15 mm in diameter and under 1 mA drive, its full range output is 72 mV and zero stability is 0.48% F.S/mon, but also the reliability of the sensor is improved and its application is widely broadened.
基金the National Key Research and Development Program(Grant No.2019YFC1906100)the National Natural Science Foundation of China(Grant Nos.11974067 and 12074054)+1 种基金the Natural Science Foundation Project of CQ CSTC(cstc2019jcyj-msxmX0145,cstc2019jcyj-bshX0042,and cstc2019jcyj-msxmX0828)the Sharing Fund of Chongqing University’s Large-scale Equipment.
文摘Benefiting from the induced image charge on film surface,the nanoparticle aggregating on metal exhibits interesting optical properties.In this work,a linear metal nanoparticle trimer on metal film system has been investigated to explore the novel optical phenomenon.Both the electric field and surface charge distributions demonstrate the light is focused on film greatly by the nanoparticles at two sides,which could be strongly modulated by the wavelength of incident light.And the influence of nanoparticle in middle on this light focusing ability has also been studied here,which is explained by the plasmon hybridization theory.Our finding about light focusing in nanoparticle aggregating on metal film not only enlarges the novel phenomenon of surface plasmon but also has great application prospect in the field of surface-enhanced spectra,surface catalysis,solar cells,water splitting,etc.
文摘With brief statements of the linear electro-optical modulation and magnetooptical modulation, using the method of resultant of optical amplitude vectors and the methed of Jones matrix, formulas for intensity of transmitted light through the optical analyzer of various composition of electro-optical effect with magneto-optical effect are derived. The results show that the output beam from the analyzer carries information on current (or magnetic field), voltage (or electric field), active power and apparent power. When the light beam transmitted through the analyzer are transformed into electric signals, three kinds of information are included: the DC term corresponding to an active power, the term with frequency ω(50 Hz) corresponding to current or voltage, and the term with frequency 2ω(100 Hz) corresponding to an apparnt power.So, we can use the electric filter circuit to pick out the DC component for measuring active power; to pick out the component with frequency ω(50 Hz) for measuring current or voltage; and to pick out the component with frequency 2ω(100 Hz) for measuring apparent power. The paper discusses what quantities are measured when the analyzer is set on certain definite values, and ponts out the optimum selection for various measurements.
文摘As the quality of power LED improves and the cost of power LED reduces, semiconductor lighting will replace incandescent and fluorescent lighting gradually, causing another revolution on the lighting history. And its driving solution has been greatly accelerated. Based on the white power LED I-V characteristics and the application ambiance, proposed is a new LED lighting solution, suiting indoor and outdoor illumination. According to the test results, the design is optimized, and the electrical efficiency is 95% and the output current deviation is 13.0%.