The paper studied the effect of high-voltage electrostatic fields on the postharvest quality of strawberries. The results showed that the respiration rate decreased significantly, the content of soluble solids kept at...The paper studied the effect of high-voltage electrostatic fields on the postharvest quality of strawberries. The results showed that the respiration rate decreased significantly, the content of soluble solids kept at high level, and the activities of polygalacturonase and cx-cellulase decreased, while the fruit firmness declined slowly. On the seventh day of storage, the rotten rate of strawberries treated by HVEF was 5%, the control group was 15%.展开更多
In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were investigated.According to the test ...In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were investigated.According to the test results,three-layer particleboard was designed.Particleboard face layers made with mixture of A,B,and C.The core layer made with D.The ratio of core layer to face layers is 50:50.Three-layer particleboard were fabricated with 12%urea-formaldehyde(UF)resins and three different high voltage electrostatic field intensities(0 kv,30 kv,60 kv).The internal bond(IB)strength,modulus of rupture(MOR),modulus of elasticity(MOE),thickness swelling(TS),and water absorption(WA)of particleboard were evaluated.The density distribution of the three-layer particleboard were examined by vertical density profiles(VDP),and the bonding mechanism and functional groups changes in the particles were analyzed by FTIR analysis.The results showed that HVEF treatment intensity play a remarkable role in properties of particleboard.The particleboard with higher electrostatic field intensities treatment has higher MOE,MOR,IB,and TS.Under HVEF treatment(60 kv),the MOR,modulus of MOE,and IB of three-layer particleboard were 23.61 N/mm^(2),2787.09 N/mm^(2),and 0.86 N/mm^(2),respectively.FTIR indicated that the surface activity of wood particles was increased electric field treatment.展开更多
Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Her...Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Herein,the effect of electrostatic interaction on regulating an anion-rich solvation is firstly proposed.The moderate electrostatic interaction between anion and solvent promotes anion to enter the solvation sheath,inducing stable solid electrolyte interphase with fast Li+transport kinetics on the anode.This asdesigned electrolyte exhibits excellent compatibility with Li metal anode(a Li deposition/stripping Coulombic efficiency of 99.3%)and high-voltage LiCoO_(2) cathode.Consequently,the 50μm-thin Li||high-loading LiCoO_(2) cells achieve significantly improved cycling performance under stringent conditions of high voltage over 4.5 V,lean electrolyte,and wide temperature range(-20 to 60℃).This work inspires a groundbreaking strategy to manipulate the solvation structure through regulating the interactions of solvent and anion for highperformance Li metal batteries.展开更多
A certain number of charges are deposited on the surface of high-voltage solar array because of effects of space plasma,high-energy charged particles,and solar illumination,hence the surface is charged.Phenomena of el...A certain number of charges are deposited on the surface of high-voltage solar array because of effects of space plasma,high-energy charged particles,and solar illumination,hence the surface is charged.Phenomena of electrostatic discharge(ESD) occur on the surface when the deposited charges exceed a threshold amount.In this paper,the mechanism of this ESD is discussed.The ground simulation experiment of the ESD using spacecraft material under surface charging is described,and a novel ESD protecting method for high-voltage solar array,i.e.an active protecting method based on the local strong electric field array is proposed.The results show that the reversal potential gradient field between the cover surface and the substrate materials of high-voltage solar array is a triggering factor for the ESD on the array.The threshold voltage for the ESD occurring on the surface is about 500 V.The charged particles could be deflected using the electric field active protecting method,and hence the ESD on the surface is avoided even when the voltage on the conductor array increases to a certain value.These results pave the way for further developing the protecting measures for high-voltage solar arrays.展开更多
The critical electric fields of hot SF_6 are calculated including both electron andion kinetics in wide ranges of temperature and pressure,namely from 300 K up to 4000 K and2 atmospheres up to 32 atmospheres respectiv...The critical electric fields of hot SF_6 are calculated including both electron andion kinetics in wide ranges of temperature and pressure,namely from 300 K up to 4000 K and2 atmospheres up to 32 atmospheres respectively.Based on solving a multi-term electron Boltz-mann equation the calculations use improved electron-gas collision cross sections for twelve SF_6dissociation products with a particular emphasis on the electron-vibrating molecule interactions.The ion kinetics is also considered and its role on the critical field becomes non negligible as thetemperature is above 2000 K.These critical fields are then used in hydrodynamics simulationswhich correctly predict the circuit breaker behaviours observed in the case of breaking tests.展开更多
Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding in...Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding interactions of KGM were reduced after being treated with high-voltage pulse electric field,but there was no significant effect on its fiber chain form and thermal characteristics.Results of the study can provide a useful reference for further study on the structure and property of KGM,and especially can provide theoretical basis for the effect of physical field on the foodstuff deep processing related to KGM.展开更多
A novel structure of AlGaN/GaN Schottky barrier diode(SBD) featuring electric field optimization techniques of anode-connected-field-plate(AFP) and magnesium-doped p-type buried layer under the two-dimensional electro...A novel structure of AlGaN/GaN Schottky barrier diode(SBD) featuring electric field optimization techniques of anode-connected-field-plate(AFP) and magnesium-doped p-type buried layer under the two-dimensional electron gas(2DEG) channel is proposed.In comparison with conventional AlGaN/GaN SBDs,the magnesium-doped p-type buried layer in the proposed structure can provide holes that can help to deplete the surface 2DEG.As a result,surface field strength around the electrode edges is significantly suppressed and the electric field along the channel is distributed more evenly.Through 2D numerical analysis,the AFP parameters(field plate length,L AFP,and field plate height,T AFP) and p-type buried layer parameters(p-type layer concentration,N P,and p-type layer thickness,T P) are optimized to achieve a three-equal-peak surface channel field distribution under exact charge balance conditions.A novel structure with a total drift region length of 10.5 μm and a magnesium-doped p-type concentration of 1 × 1017cm-3achieves a high breakdown voltage(V B) of 1.8 kV,showing 5 times improvement compared with the conventional SBD with the same device dimension.展开更多
In order to improve hydrophobic characteristics which will affect the service performance of fast-growing poplar due to growing bacteria in the humid environment.In this study,a simple method was proposed to treat pop...In order to improve hydrophobic characteristics which will affect the service performance of fast-growing poplar due to growing bacteria in the humid environment.In this study,a simple method was proposed to treat poplar via the high voltage electric field(HVEF)with copper as the electrode plate.Scanning electron microscope(SEM),Fourier transforms infrared spectroscopy(FTIR),X-ray diffraction(XRD)and contact angle tester were adopted to evaluate the surface morphology,surface group of poplar,crystallinity and wettability under HVEF.It was found by SEM that a large number of copper particles were uniformly attached to the surface of poplar.In all three sections,the weight percentage of the Cu element was accounting for more than half.The diffraction peaks of copper-containing compounds appeared in the(XRD).FTIR analysis confirmed that the reaction between copper and poplar took place.The surface contact angle of three sections of poplar increased in the following order:cross section<radial section<tangential section(increased by 34°,45°and 53°,respectively).An environmentfriendly and efficient method of HVEF treating fast-growing wood with copper as the electrode plate can promote its outdoor application.展开更多
For the studies in the field of high voltage power transmission, this paper has adopted the method of finite element node potential, and put forward two kinds of high pressure sensor-fixture modeling scheme for the se...For the studies in the field of high voltage power transmission, this paper has adopted the method of finite element node potential, and put forward two kinds of high pressure sensor-fixture modeling scheme for the sensor-fixture of the high voltage side, the simulation analysis shows that the sensor-fixture surface should be smooth, and should not appear the conclusion of edges and corners. While through establishing the four clamps assembly optimized model, and simulates the strain gages, fixtures and conductor surface field strength and electric field distribution in the model as a whole in turn, this paper Finally got the optimal size of fixture structure and assembly of each part reasonable location layout.展开更多
This article firstly describes the main technical parameters and performance of the high power supply of electrostatic precipitator, and then describes the structure, principle and characteristic of power supply of el...This article firstly describes the main technical parameters and performance of the high power supply of electrostatic precipitator, and then describes the structure, principle and characteristic of power supply of electrostatic precipitator, and finally analyses the common faults of power supply of electrostatic precipitator in the operation and puts forward the methods of dealing with breakdown. Operation results show that the system is stable and reliable, and overall performance and the efficiency of dust control have been improved significantly. The scheme has been well applied in the field of environmental protection and dust removal.展开更多
Objective In order to discuss the effects of hig h-voltage alternative electromagn etic field on stroke.Method126cases of stroke patients were treated by high-volta ge alternative electromagnetic fie ld,combined with ...Objective In order to discuss the effects of hig h-voltage alternative electromagn etic field on stroke.Method126cases of stroke patients were treated by high-volta ge alternative electromagnetic fie ld,combined with kinesiotherapy an d occupational combine therapy.Result66cases showed significant effect,52cases were improved and 8cases showed no improvement.The score of Barthel and FIM assessment after treatment was increased significantly(P <0.001).Conclusion The effect of high-voltage alternat ive electromagnetic field on stroke is sig-nificant.展开更多
A new analytical model of high voltage silicon on insulator(SOI) thin film devices is proposed,and a formula of silicon critical electric field is derived as a function of silicon film thickness by solving a 2D Poisso...A new analytical model of high voltage silicon on insulator(SOI) thin film devices is proposed,and a formula of silicon critical electric field is derived as a function of silicon film thickness by solving a 2D Poisson equation from an effective ionization rate,with a threshold energy taken into account for electron multiplying.Unlike a conventional silicon critical electric field that is constant and independent of silicon film thickness,the proposed silicon critical electric field increases sharply with silicon film thickness decreasing especially in the case of thin films,and can come to 141 V/μm at a film thickness of 0.1 μm which is much larger than the normal value of about 30 V/μm.From the proposed formula of silicon critical electric field,the expressions of dielectric layer electric field and vertical breakdown voltage(VB,V) are obtained.Based on the model,an ultra thin film can be used to enhance dielectric layer electric field and so increase vertical breakdown voltage for SOI devices because of its high silicon critical electric field,and with a dielectric layer thickness of 2 μm the vertical breakdown voltages reach 852 and 300V for the silicon film thicknesses of 0.1 and 5 μm,respectively.In addition,a relation between dielectric layer thickness and silicon film thickness is obtained,indicating a minimum vertical breakdown voltage that should be avoided when an SOI device is designed.2D simulated results and some experimental results are in good agreement with analytical results.展开更多
A novel substrate trigger semiconductor control rectifier-laterally diffused metal–oxide semiconductor(STSCRLDMOS) stacked structure is proposed and simulated using the transimission line pulser(TLP) multiple-pulse s...A novel substrate trigger semiconductor control rectifier-laterally diffused metal–oxide semiconductor(STSCRLDMOS) stacked structure is proposed and simulated using the transimission line pulser(TLP) multiple-pulse simulation method in a 0.35-μm, 60-V biploar-CMOS-DMOS(BCD) process without additional masks. On account of a very low holding voltage, it is susceptible to latch-up-like danger for the semiconductor control rectifier-laterally diffused metal–oxide semiconductor(SCR-LDMOS) in high-voltage electro-static discharge(ESD) protection applications. Although the conventional stacking structure has achieved strong latch-up immunity by increasing holding voltage, excessive high trigger voltage does not meet requirements for an ESD protection device. The holding voltage of the proposed stacked structure is proportional to the stacking number, whereas the trigger voltage remains nearly the same. A high holding voltage of 30.6 V and trigger voltage of 75.4 V are achieved.展开更多
In this paper,the influence of a drain field plate(FP)on the forward blocking characteristics of an AlGaN/GaN high electron mobility transistor(HEMT)is investigated.The HEMT with only a gate FP is optimized,and breakd...In this paper,the influence of a drain field plate(FP)on the forward blocking characteristics of an AlGaN/GaN high electron mobility transistor(HEMT)is investigated.The HEMT with only a gate FP is optimized,and breakdown voltage VBRis saturated at 1085 V for gate–drain spacing LGD≥8μm.On the basis of the HEMT with a gate FP,a drain FP is added with LGD=10μm.For the length of the drain FP LDF≤2μm,VBRis almost kept at 1085 V,showing no degradation.When LDFexceeds 2μm,VBRdecreases obviously as LDFincreases.Moreover,the larger the LDF,the larger the decrease of VBR.It is concluded that the distance between the gate edge and the drain FP edge should be larger than a certain value to prevent the drain FP from affecting the forward blocking voltage and the value should be equal to the LGDat which VBR begins to saturate in the first structure.The electric field and potential distribution are simulated and analyzed to account for the decrease of VBR.展开更多
In this paper the influences of the metal-gate and high-k/SiO 2 /Si stacked structure on the metal-oxide-semiconductor field-effect transistor(MOSFET) are investigated.The flat-band voltage is revised by considering t...In this paper the influences of the metal-gate and high-k/SiO 2 /Si stacked structure on the metal-oxide-semiconductor field-effect transistor(MOSFET) are investigated.The flat-band voltage is revised by considering the influences of stacked structure and metal-semiconductor work function fluctuation.The two-dimensional Poisson's equation of potential distribution is presented.A threshold voltage analytical model for metal-gate/high-k/SiO 2 /Si stacked MOSFETs is developed by solving these Poisson's equations using the boundary conditions.The model is verified by a two-dimensional device simulator,which provides the basic design guidance for metal-gate/high-k/SiO 2 /Si stacked MOSFETs.展开更多
A NFFP HVI structure which implements high breakdown voltage without using additional FFP and process steps is proposed in this paper. An 850 V high voltage half bridge gate drive IC with the NFFP HVI structure is exp...A NFFP HVI structure which implements high breakdown voltage without using additional FFP and process steps is proposed in this paper. An 850 V high voltage half bridge gate drive IC with the NFFP HVI structure is experimentally realized using a thin epitaxial BCD process. Compared with the MFFP HVI structure, the proposed NFFP HVI structure shows simpler process and lower cost. The high side offset voltage in the half bridge gate drive IC with the NFFP HVI structure is almost as same as that with the self-shielding stru cture.展开更多
Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-freque...Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-frequency electromagnetic fields on the environment and which are capable of modifying and destroying our ecosystem. Particular interest was given in this article due to a massive influx of population living near high voltage lines. The analysis and simulation of the influence of low frequency electromagnetic fields on living beings in the vicinity of high voltage sources 132 kV and 220 kV in urban areas in DR Congo is the subject of our research with a view to estimating the level of exposure of humans to low frequency electromagnetic fields. To carry out our research, we used the classic method of analyzing the field produced near a high voltage line based on Maxwell’s image theory, the Maxwell-Gauss theorem and Maxwell-Ampère theorem to model and quantify low-frequency electromagnetic fields in the vicinity of high-voltage lines. The 2D FDTD numerical formulation was developed from telegraphers’ equations and allowed us to obtain models of current and voltage induced by electromagnetic fields on living beings below and near HV lines. The different simulations carried out on the proposed models illustrate the effects of the electrical and geometric parameters of the pylons on the distribution of the electromagnetic field in the vicinity of the HV lines. The results obtained were compared to the safety limits recommended by the standards.展开更多
基金This research was funded by the National Natural Sci—ence Foundation of China(30170665).
文摘The paper studied the effect of high-voltage electrostatic fields on the postharvest quality of strawberries. The results showed that the respiration rate decreased significantly, the content of soluble solids kept at high level, and the activities of polygalacturonase and cx-cellulase decreased, while the fruit firmness declined slowly. On the seventh day of storage, the rotten rate of strawberries treated by HVEF was 5%, the control group was 15%.
基金The Authors acknowledge funding support by the National Key R&D Program of China(2017YFC0703501)The authors wish to acknowledge the National Natural Science Foundation of China(Grant No.32071700).
文摘In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were investigated.According to the test results,three-layer particleboard was designed.Particleboard face layers made with mixture of A,B,and C.The core layer made with D.The ratio of core layer to face layers is 50:50.Three-layer particleboard were fabricated with 12%urea-formaldehyde(UF)resins and three different high voltage electrostatic field intensities(0 kv,30 kv,60 kv).The internal bond(IB)strength,modulus of rupture(MOR),modulus of elasticity(MOE),thickness swelling(TS),and water absorption(WA)of particleboard were evaluated.The density distribution of the three-layer particleboard were examined by vertical density profiles(VDP),and the bonding mechanism and functional groups changes in the particles were analyzed by FTIR analysis.The results showed that HVEF treatment intensity play a remarkable role in properties of particleboard.The particleboard with higher electrostatic field intensities treatment has higher MOE,MOR,IB,and TS.Under HVEF treatment(60 kv),the MOR,modulus of MOE,and IB of three-layer particleboard were 23.61 N/mm^(2),2787.09 N/mm^(2),and 0.86 N/mm^(2),respectively.FTIR indicated that the surface activity of wood particles was increased electric field treatment.
基金supported by National Nature Science Foundation of China(No.51872157 and No.52072208)National Key R&D Program of China 2021YFA1202802Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2017BT01N111)。
文摘Through tailoring interfacial chemistry,electrolyte engineering is a facile yet effective strategy for highperformance lithium(Li)metal batteries,where the solvation structure is critical for interfacial chemistry.Herein,the effect of electrostatic interaction on regulating an anion-rich solvation is firstly proposed.The moderate electrostatic interaction between anion and solvent promotes anion to enter the solvation sheath,inducing stable solid electrolyte interphase with fast Li+transport kinetics on the anode.This asdesigned electrolyte exhibits excellent compatibility with Li metal anode(a Li deposition/stripping Coulombic efficiency of 99.3%)and high-voltage LiCoO_(2) cathode.Consequently,the 50μm-thin Li||high-loading LiCoO_(2) cells achieve significantly improved cycling performance under stringent conditions of high voltage over 4.5 V,lean electrolyte,and wide temperature range(-20 to 60℃).This work inspires a groundbreaking strategy to manipulate the solvation structure through regulating the interactions of solvent and anion for highperformance Li metal batteries.
基金Project supported by National Natural Science Foundation of China（51177173）, Elec- tromagnetic Environment Effect Key Laboratory Foundation（9140C87010313 JB34004）.
文摘A certain number of charges are deposited on the surface of high-voltage solar array because of effects of space plasma,high-energy charged particles,and solar illumination,hence the surface is charged.Phenomena of electrostatic discharge(ESD) occur on the surface when the deposited charges exceed a threshold amount.In this paper,the mechanism of this ESD is discussed.The ground simulation experiment of the ESD using spacecraft material under surface charging is described,and a novel ESD protecting method for high-voltage solar array,i.e.an active protecting method based on the local strong electric field array is proposed.The results show that the reversal potential gradient field between the cover surface and the substrate materials of high-voltage solar array is a triggering factor for the ESD on the array.The threshold voltage for the ESD occurring on the surface is about 500 V.The charged particles could be deflected using the electric field active protecting method,and hence the ESD on the surface is avoided even when the voltage on the conductor array increases to a certain value.These results pave the way for further developing the protecting measures for high-voltage solar arrays.
文摘The critical electric fields of hot SF_6 are calculated including both electron andion kinetics in wide ranges of temperature and pressure,namely from 300 K up to 4000 K and2 atmospheres up to 32 atmospheres respectively.Based on solving a multi-term electron Boltz-mann equation the calculations use improved electron-gas collision cross sections for twelve SF_6dissociation products with a particular emphasis on the electron-vibrating molecule interactions.The ion kinetics is also considered and its role on the critical field becomes non negligible as thetemperature is above 2000 K.These critical fields are then used in hydrodynamics simulationswhich correctly predict the circuit breaker behaviours observed in the case of breaking tests.
基金Supported by the National Natural Science Foundation of China (30901004,30871749,31071518)the Natural Science Foundation of Fujian Province (2011J01285)+1 种基金Scientific and Technological Project of Guangdong Province (2010B080701079)Scientific and Technological Project of Guangdong scholars (10B005D)
文摘Structures of KGM treated in two high-voltage pulse electric fields were characterized by infrared spectroscopy,Raman spectroscopy,X-ray diffraction and so on.The results showed that intermolecular hydrogen bonding interactions of KGM were reduced after being treated with high-voltage pulse electric field,but there was no significant effect on its fiber chain form and thermal characteristics.Results of the study can provide a useful reference for further study on the structure and property of KGM,and especially can provide theoretical basis for the effect of physical field on the foodstuff deep processing related to KGM.
基金Project supported by the Science Foundation of the Ministry of Education of China (Grant No.20100101110056)the Natural Science Foundation of Zhejiang Province of China for Distinguished Young Scholars (Grant No.R1100468)
文摘A novel structure of AlGaN/GaN Schottky barrier diode(SBD) featuring electric field optimization techniques of anode-connected-field-plate(AFP) and magnesium-doped p-type buried layer under the two-dimensional electron gas(2DEG) channel is proposed.In comparison with conventional AlGaN/GaN SBDs,the magnesium-doped p-type buried layer in the proposed structure can provide holes that can help to deplete the surface 2DEG.As a result,surface field strength around the electrode edges is significantly suppressed and the electric field along the channel is distributed more evenly.Through 2D numerical analysis,the AFP parameters(field plate length,L AFP,and field plate height,T AFP) and p-type buried layer parameters(p-type layer concentration,N P,and p-type layer thickness,T P) are optimized to achieve a three-equal-peak surface channel field distribution under exact charge balance conditions.A novel structure with a total drift region length of 10.5 μm and a magnesium-doped p-type concentration of 1 × 1017cm-3achieves a high breakdown voltage(V B) of 1.8 kV,showing 5 times improvement compared with the conventional SBD with the same device dimension.
文摘In order to improve hydrophobic characteristics which will affect the service performance of fast-growing poplar due to growing bacteria in the humid environment.In this study,a simple method was proposed to treat poplar via the high voltage electric field(HVEF)with copper as the electrode plate.Scanning electron microscope(SEM),Fourier transforms infrared spectroscopy(FTIR),X-ray diffraction(XRD)and contact angle tester were adopted to evaluate the surface morphology,surface group of poplar,crystallinity and wettability under HVEF.It was found by SEM that a large number of copper particles were uniformly attached to the surface of poplar.In all three sections,the weight percentage of the Cu element was accounting for more than half.The diffraction peaks of copper-containing compounds appeared in the(XRD).FTIR analysis confirmed that the reaction between copper and poplar took place.The surface contact angle of three sections of poplar increased in the following order:cross section<radial section<tangential section(increased by 34°,45°and 53°,respectively).An environmentfriendly and efficient method of HVEF treating fast-growing wood with copper as the electrode plate can promote its outdoor application.
文摘For the studies in the field of high voltage power transmission, this paper has adopted the method of finite element node potential, and put forward two kinds of high pressure sensor-fixture modeling scheme for the sensor-fixture of the high voltage side, the simulation analysis shows that the sensor-fixture surface should be smooth, and should not appear the conclusion of edges and corners. While through establishing the four clamps assembly optimized model, and simulates the strain gages, fixtures and conductor surface field strength and electric field distribution in the model as a whole in turn, this paper Finally got the optimal size of fixture structure and assembly of each part reasonable location layout.
文摘This article firstly describes the main technical parameters and performance of the high power supply of electrostatic precipitator, and then describes the structure, principle and characteristic of power supply of electrostatic precipitator, and finally analyses the common faults of power supply of electrostatic precipitator in the operation and puts forward the methods of dealing with breakdown. Operation results show that the system is stable and reliable, and overall performance and the efficiency of dust control have been improved significantly. The scheme has been well applied in the field of environmental protection and dust removal.
文摘Objective In order to discuss the effects of hig h-voltage alternative electromagn etic field on stroke.Method126cases of stroke patients were treated by high-volta ge alternative electromagnetic fie ld,combined with kinesiotherapy an d occupational combine therapy.Result66cases showed significant effect,52cases were improved and 8cases showed no improvement.The score of Barthel and FIM assessment after treatment was increased significantly(P <0.001).Conclusion The effect of high-voltage alternat ive electromagnetic field on stroke is sig-nificant.
基金Project supported by the National Natural Science Foundation of China (Grant No 60436030)National Laboratory of Analogue Integrated Circuits,China (Grant No 9140C090305060C09)
文摘A new analytical model of high voltage silicon on insulator(SOI) thin film devices is proposed,and a formula of silicon critical electric field is derived as a function of silicon film thickness by solving a 2D Poisson equation from an effective ionization rate,with a threshold energy taken into account for electron multiplying.Unlike a conventional silicon critical electric field that is constant and independent of silicon film thickness,the proposed silicon critical electric field increases sharply with silicon film thickness decreasing especially in the case of thin films,and can come to 141 V/μm at a film thickness of 0.1 μm which is much larger than the normal value of about 30 V/μm.From the proposed formula of silicon critical electric field,the expressions of dielectric layer electric field and vertical breakdown voltage(VB,V) are obtained.Based on the model,an ultra thin film can be used to enhance dielectric layer electric field and so increase vertical breakdown voltage for SOI devices because of its high silicon critical electric field,and with a dielectric layer thickness of 2 μm the vertical breakdown voltages reach 852 and 300V for the silicon film thicknesses of 0.1 and 5 μm,respectively.In addition,a relation between dielectric layer thickness and silicon film thickness is obtained,indicating a minimum vertical breakdown voltage that should be avoided when an SOI device is designed.2D simulated results and some experimental results are in good agreement with analytical results.
文摘A novel substrate trigger semiconductor control rectifier-laterally diffused metal–oxide semiconductor(STSCRLDMOS) stacked structure is proposed and simulated using the transimission line pulser(TLP) multiple-pulse simulation method in a 0.35-μm, 60-V biploar-CMOS-DMOS(BCD) process without additional masks. On account of a very low holding voltage, it is susceptible to latch-up-like danger for the semiconductor control rectifier-laterally diffused metal–oxide semiconductor(SCR-LDMOS) in high-voltage electro-static discharge(ESD) protection applications. Although the conventional stacking structure has achieved strong latch-up immunity by increasing holding voltage, excessive high trigger voltage does not meet requirements for an ESD protection device. The holding voltage of the proposed stacked structure is proportional to the stacking number, whereas the trigger voltage remains nearly the same. A high holding voltage of 30.6 V and trigger voltage of 75.4 V are achieved.
基金Project supported by the Program for New Century Excellent Talents in University,China(Grant No.NCET-12-0915)the National Natural Science Foundation of China(Grant No.61204085)
文摘In this paper,the influence of a drain field plate(FP)on the forward blocking characteristics of an AlGaN/GaN high electron mobility transistor(HEMT)is investigated.The HEMT with only a gate FP is optimized,and breakdown voltage VBRis saturated at 1085 V for gate–drain spacing LGD≥8μm.On the basis of the HEMT with a gate FP,a drain FP is added with LGD=10μm.For the length of the drain FP LDF≤2μm,VBRis almost kept at 1085 V,showing no degradation.When LDFexceeds 2μm,VBRdecreases obviously as LDFincreases.Moreover,the larger the LDF,the larger the decrease of VBR.It is concluded that the distance between the gate edge and the drain FP edge should be larger than a certain value to prevent the drain FP from affecting the forward blocking voltage and the value should be equal to the LGDat which VBR begins to saturate in the first structure.The electric field and potential distribution are simulated and analyzed to account for the decrease of VBR.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60936005 and 61076097)the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China (Grant No. 708083)the Fundamental Research Funds for the Central Universities (Grant No. 20110203110012)
文摘In this paper the influences of the metal-gate and high-k/SiO 2 /Si stacked structure on the metal-oxide-semiconductor field-effect transistor(MOSFET) are investigated.The flat-band voltage is revised by considering the influences of stacked structure and metal-semiconductor work function fluctuation.The two-dimensional Poisson's equation of potential distribution is presented.A threshold voltage analytical model for metal-gate/high-k/SiO 2 /Si stacked MOSFETs is developed by solving these Poisson's equations using the boundary conditions.The model is verified by a two-dimensional device simulator,which provides the basic design guidance for metal-gate/high-k/SiO 2 /Si stacked MOSFETs.
基金This work was supported by the National Nature Science Foundation of China under Grant No.60436030.
文摘A NFFP HVI structure which implements high breakdown voltage without using additional FFP and process steps is proposed in this paper. An 850 V high voltage half bridge gate drive IC with the NFFP HVI structure is experimentally realized using a thin epitaxial BCD process. Compared with the MFFP HVI structure, the proposed NFFP HVI structure shows simpler process and lower cost. The high side offset voltage in the half bridge gate drive IC with the NFFP HVI structure is almost as same as that with the self-shielding stru cture.
文摘Recent decades have seen rapid advances in the field of electrical engineering, such that our environment has become a sea of electrical and magnetic signals, raising questions about the possible effects of low-frequency electromagnetic fields on the environment and which are capable of modifying and destroying our ecosystem. Particular interest was given in this article due to a massive influx of population living near high voltage lines. The analysis and simulation of the influence of low frequency electromagnetic fields on living beings in the vicinity of high voltage sources 132 kV and 220 kV in urban areas in DR Congo is the subject of our research with a view to estimating the level of exposure of humans to low frequency electromagnetic fields. To carry out our research, we used the classic method of analyzing the field produced near a high voltage line based on Maxwell’s image theory, the Maxwell-Gauss theorem and Maxwell-Ampère theorem to model and quantify low-frequency electromagnetic fields in the vicinity of high-voltage lines. The 2D FDTD numerical formulation was developed from telegraphers’ equations and allowed us to obtain models of current and voltage induced by electromagnetic fields on living beings below and near HV lines. The different simulations carried out on the proposed models illustrate the effects of the electrical and geometric parameters of the pylons on the distribution of the electromagnetic field in the vicinity of the HV lines. The results obtained were compared to the safety limits recommended by the standards.
