BACKGROUND： Researches prove that the treatment of cerebral palsy by botulinus toxin （BTX-A） can improve effect and prolong effective duration. Current intensity is the important factor during injection. OBJECTIVE...BACKGROUND： Researches prove that the treatment of cerebral palsy by botulinus toxin （BTX-A） can improve effect and prolong effective duration. Current intensity is the important factor during injection. OBJECTIVE： To observe the changes of motor function and muscular intensity of children with spastic cerebral palsy after injecting BTX-A and analyze correlation between current intensity and effective duration. DESIGN： Cases control trial before and after nerves block SETTING： Capital University of Medical Sciences, China Rehabilitation Research Center PARTICIPANTS： From June 2002 to November 2004, 14 children with spastic cerebral palsy were treated by BTX-A block. All children were hospitalized in the Children Rehabilitation Department of China Rehabilitation Research Center. The children included 9 male and 5 female, and ranged from 4 to 13 years old, and average age was （6±2） years. Muscular tension ranged from grade 1 to grade 3. The diagnosis and the tape of cerebral palsy based on standard of the Fist Nationwide Cerebral Palsy Symposium, and all children were diagnosed with electroencephalogram （EEG）, CT and MRI, and permitted by their guardians. METHODS： （1） Locating and calculation： To locate block points by G6805-2A electro-therapeutic apparatus （Shanghai Huayi Electronic Instrument Plant） at the least stimulating current （continuous wave; impulse frequency; 2.667-83.333 Hz; current intensity： 0-6 mA; voltage： 6 V） to touch off muscles contraction. The current intensity of each point was recorded, and the average current intensity of each patient was calculated at the same time. （2） Dose of BTX-A： Basing upon the spastic degree and weight of patients, the dose was made certain： dose （IU）=（scores of Modified Ashworth Scale ＋2.5） xweight （kg）. The number of the block points was in all 4. The dose of injection ranged from 50 IU to 160 IU with the average of （73.6＋25.8） IU. The BTX-A was made by Lanzhou Institute of Biological Products, and each bottle contains 100 IU BTX-A. Muscular tension was evaluated by Modified Ashworth Scale. The scale ranged from grade 0 to grade 4, and the scores were from 0 to 4. The higher the scores were, the higher the muscular tension was. （3） Effect： Changes of muscular tension were evaluated by modified Ashworth Scale before and after block. Motor function was evaluated by Physician Rating Scale （PRS） before and after treatment. It contained Gait pattern, Hindfoot （ankle） position （stance-floor contact）, Hindfoot position （foot strike）, Knee position （degree of recurvation）, Crouch and Speed of gait. The scores ranged from 0 to 14. The higher the points were, the better the motor function was. （4） Effective duration： The duration was definited by the recovering of the Modified Ashworth Scale. （5） Statistic analysis： Firstly, the current intensity and the effect duration were analyzed by One-Sample Kolmogorov-Smirnov Test, the current intensity： Z= 0.456, P= 0.985, the effective duration： Z= 0.557, P= 0.915. Both data were normal distribution. Secondly, both data were analyzed by Linear Regression. The efficiency of the BTX-A block was analyzed by paired-samples t test. MAIN OUTCOME MEASURES： （1） Changes of motor function of muscular tension; （2） correlation between current intensity and effective duration. RESULTS： Fourteen children with spastic cerebral palsy were all involved in the final analysis. （1） Therapeutic effect： The average score of Ashworth scale after block was lower than that before block [（1.02±0.34） points vs. （2.12±0.48） points, t= 3.644, P〈 0.01]. The average score of RPS after block was higherthan that before block [（9.75±2.78） points vs. （6.16±0.58） points, t =13.222, P〈 0.01]. （2） Relation between the current intensity and the effective duration： The current intensity was （0.1857±0.0506） mA, and the effective duration was （26.36±4.48） weeks. The current intensity was negative correlation with effective duration （r = -0.775, P = 0.01 ）. CONCLUSION： （1） BTX-A occlusion can decrease muscular tension and improve motor function of lower limbs of children with spastic cerebral palsy. （2） The lower the current intensity is, the longer the effective duration is.展开更多
The microplasma oxidation process of LY 12 Al alloy in Na2SiO3-KOH-NaAL2 system has been studied. The voltage-time curve of oxidation process is changed with the variation of current ...The microplasma oxidation process of LY 12 Al alloy in Na2SiO3-KOH-NaAL2 system has been studied. The voltage-time curve of oxidation process is changed with the variation of current densities. The voltage breakdown and hardness of coating increase with increasing current density. The phase composition, morphologies, element and the distribution of ceramic coating are investigated by XRD, EPMA.展开更多
In this work,we discuss the origin of several anomalies present in the point-contact Andreev reflection spectra of（Li1-xFex）OHFeSe,LiTi2O4,and La2-xCexCuO4.While these features are similar to those stemming from int...In this work,we discuss the origin of several anomalies present in the point-contact Andreev reflection spectra of（Li1-xFex）OHFeSe,LiTi2O4,and La2-xCexCuO4.While these features are similar to those stemming from intrinsic superconducting properties,such as Andreev reflection,electron-boson coupling,multigap superconductivity,d-wave and p-wave pairing symmetry,they cannot be accounted for by the modified Blonder–Tinkham–Klapwijk（BTK） model,but require to consider critical current effects arising from the junction geometry.Our results point to the importance of tracking the evolution of the dips and peaks in the differential conductance as a function of the bias voltage,in order to correctly deduce the properties of the superconducting state.展开更多
The effect of excitation current intensity on the mechanical properties of ZL205 A castings solidified under a traveling magnetic field was studied. The results of the experiment indicate that the excitation current i...The effect of excitation current intensity on the mechanical properties of ZL205 A castings solidified under a traveling magnetic field was studied. The results of the experiment indicate that the excitation current intensity of the traveling magnetic field has a great influence on the mechanical properties of the ZL205 A castings. When the excitation current intensity is 15 A, the tensile strength and elongation of ZL205 A alloy castings increase 27.2% and 67.7%, respectively, compared with those of the same alloy solidified under gravity. The improvement of mechanical properties is attributed to the decrease of micro-porosity in the alloy. Under the traveling magnetic field, the feeding pressure in the alloy melt before solidification can be enhanced due to the electromagnetic force. Moreover, the melt flow induced by the traveling magnetic field can decrease the temperature gradient. The feeding resistance will be increased because the temperature gradient decrease. So traveling magnetic field has an optimum effect on feeding.展开更多
Purines have a recognized importance as intercellular mes- sengers. These molecules play an important role in the de- velopment and maintenance of the central nervous system （CNS）, as well as in its response to path...Purines have a recognized importance as intercellular mes- sengers. These molecules play an important role in the de- velopment and maintenance of the central nervous system （CNS）, as well as in its response to pathological conditions. Both adenine and guanine-based purines can be released from astrocytes, where they play a relevant role as extracel- lular signaling molecules. Particularly, the nucleoside gua- nosine has been proposed as an extracellular molecule that regulates the response of CNS to damage. Following injury, this nucleoside attains high concentrations in the extracel- lular space, where it activates multiple signaling pathways.展开更多
Hugoniot relations of a two-dimensional axial shock with current and magnetic field in a cylindrical shock tube were investigated by a numerical method. The radial profiles of the magnetic field, electric current, pre...Hugoniot relations of a two-dimensional axial shock with current and magnetic field in a cylindrical shock tube were investigated by a numerical method. The radial profiles of the magnetic field, electric current, pressures, flow velocities and temperatures between the up- and down-stream radial force-balanced plasma of the shock were revealed by numerical analysis. It is clearly found that the axial shock can lead to two effects： one is an inverse skin effect （i.e., the current density rises towards the center of the conductor）, the another is a reversed current effect which occurs near the edge and about a half radius. It is also found that the radial gradient of pressure, density and temperature all become very large near the center due to the axial shock.展开更多
An improved small-signal equivalent circuit of HBT concerning the AC current crowding effect is proposed in this paper. AC current crowding effect is modeled as a parallel RC circuit composed of Cbi and Rbi, with dist...An improved small-signal equivalent circuit of HBT concerning the AC current crowding effect is proposed in this paper. AC current crowding effect is modeled as a parallel RC circuit composed of Cbi and Rbi, with distributed base-collector junction capacitance also taken into account. The intrinsic portion is taken as a whole and extracted directly from the measured Sparameters in the whole frequency range of operation without any special test structures. An HBT device with a 2 × 20 μm^(2) emitter-area under three different biases were used to demonstrate the extraction and verify the accuracy of the equivalent circuit.展开更多
The effect of the wave accessibility condition on the lower hybrid cm＇rent drive in the experimental advanced superconductor Tokamak （EAST） plasma with H-mode operation is studied. Based on a simplified model, a mo...The effect of the wave accessibility condition on the lower hybrid cm＇rent drive in the experimental advanced superconductor Tokamak （EAST） plasma with H-mode operation is studied. Based on a simplified model, a mode conversion layer of the lower hybrid wave between the fast wave branch and the slow wave branch is proved to exist in the plasma periphery for typical EAST H-mode parameters. Under the framework of the lower hybrid wave simulation code （LSC）, the wave ray trajectory and the associated current drive are calculated numerically. The results show that the wave accessibility condition plays an important role on the lower hybrid current drive in EAST plasma. For wave rays with parallel refractive index n｜｜= 2.1 or n｜｜ = 2.5 launched from the outside midplane, the wave rays may penetrate the core plasma due to the toroida] geometry effect, while numerous reflections of the wave ray trajectories in the plasma periphery occur. However, low current drive efficiency is obtained. Meanwhile, the wave accessibility condition is improved if a higher confined magnetic field is applied. The simulation results show that for plasma parameters under present EAST H-mode operation, a significant lower hybrid wave current drive could be obtained for the wave spectrum with peak value n｜｜ = 2.1 if a toroidal magnetic field BT =2.5 T is applied.展开更多
It is known that eddy current effect has a great influence on magnetic flux leakage testing(MFL).Usually,contacttype encoder wheels are used to measure MFL testing speed to evaluate the effect and further compensate t...It is known that eddy current effect has a great influence on magnetic flux leakage testing(MFL).Usually,contacttype encoder wheels are used to measure MFL testing speed to evaluate the effect and further compensate testing signals.This speed measurement method is complicated,and inevitable abrasion and occasional slippage will reduce the measurement accuracy.In order to solve this problem,based on eddy current effect due to the relative movement,a speed measurement method is proposed,which is contactless and simple.In the high-speed MFL testing,eddy current induced in the specimen will cause an obvious modification to the applied field.This modified field,which is measured by Hall sensor,can be utilized to reflect the moving speed.Firstly,the measurement principle is illustrated based on Faraday’s law.Then,dynamic finite element simulations are conducted to investigate the modified magnetic field distribution.Finally,laboratory experiments are performed to validate the feasibility of the proposed method.The results show that Bmz(r1)and Bmx(r2)have a linear relation with moving speed,which could be used as an alternative measurement parameter.展开更多
The article theoretically studied the charge-exchange effects on space charge limitedelectron and ion current densities of non-relativistic one-dimensional slab ion diode, and comparedwith those of without charge exch...The article theoretically studied the charge-exchange effects on space charge limitedelectron and ion current densities of non-relativistic one-dimensional slab ion diode, and comparedwith those of without charge exchange.展开更多
Three-dimensional thermo-electrical finite element analyses were conducted to simulate the current density and temperature distributions in solder bump joints with different pad geometries.The effects of pad thickness...Three-dimensional thermo-electrical finite element analyses were conducted to simulate the current density and temperature distributions in solder bump joints with different pad geometries.The effects of pad thickness,diameter and shape on current density and temperate distributions were investigated respectively.It was found that pads with larger thickness or/and diameter could reduce current density and temperature in solder bump significantly.Pad shapes affected the current density and temperature distributions in solder bumps.The relatively low current density and temperature didn＇t occur in the bump joint with traditional rounded pad but occurred in bump joints with octagonal and nonagonal pads respectively.Therefore,optimized pad geometry may be designed to alleviate the current crowding effect and reduce the bump temperature,and therefore delay electromigration failure and increase the mean-time-to-failure.展开更多
The spark plasma sintering（SPS） method was used to study the mechanism of reaction interface between Zr and Ti3AlC2 with electric current going through it. It was found that electric current greatly reduced the bond...The spark plasma sintering（SPS） method was used to study the mechanism of reaction interface between Zr and Ti3AlC2 with electric current going through it. It was found that electric current greatly reduced the bonding temperature of Zr and Ti3AlC2. By the micro-structure analysis of the interface through SEM/EDS, it was found that Al atoms diffused from the Ti3AlC2 substrate into the Zr side and reacted with Zr to form the Zr-Al compounds at the interface, which is the strengthening mechanism of Ti3AlC2-Zr bonding. The thickness of reaction layers（Zr-Al alloy） was from 0.879 to 13.945 mm depending on different sintering condition. Current direction, heating rate, soaking time, pulse patterns all influenced the diffusion of Al atoms which affected the joining quality of Zr and Ti3AlC2.展开更多
The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current...The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current are studied via particle-in-cell simulations. It is found that the energetic ions and background ions can be treated separately as different species, and they satisfy their individual Bohm criterion at the sheath edge. It is shown that the energetic ions can significantly affect the ion saturation current if their concentration is greater than root T-e/(gamma T-i2(i2)), where T-e is the electron temperature, and gamma(i2) and T-i2 represent the polytropic coefficient and temperature of energetic ions, respectively. As a result, the floating potential and the I-V characteristic profile are strongly influenced by the energetic ions. When the energetic ion current dominates the ion saturation current, an analysis of the ion saturation current will yield the energetic ion temperature rather than the electron temperature.展开更多
Compared with the conventionally used i=iosinωt alternating current, using asymmetric triangular and pulse wave as input signals can greatly enhance the incision's sensitivity of 'dE/dt-E'oscillogram.
Aiming at the approximate measurement of magnetic rotation angle in optical current sensor based on light intensity detection mode,this paper proposes a current measurement method based on triangular constant transfor...Aiming at the approximate measurement of magnetic rotation angle in optical current sensor based on light intensity detection mode,this paper proposes a current measurement method based on triangular constant transformation to reconstruct magnetic rotation angle,so as to avoid the large current measurement error caused by the approximate measurement of the magnetic rotation angle.By extracting the direct current(DC)component and the alternating current(AC)component of the light intensity signal detected by the photoelectric detector(PD),the sine signal containing the magnetic rotation angle is directly obtained by dividing the two components,and then the triangular identity transformation method is used to linearly demodulate the magnetic rotation angle and reconstruct the current waveform.The experimental results show that the relative error of current measurement does not exceed 1.40%in the current range of 0.05—0.50 A,which is less than the approximate linear measurement(ALM)method,and the magnetic rotation angle and the current have a good linear relationship.展开更多
The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain ...The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.展开更多
The tidal current is generally predominant in China's offshore areas. The vertical structure of the observedtidal current is quite complicated with the presence of seasonal thermocline. The observed tidal current ...The tidal current is generally predominant in China's offshore areas. The vertical structure of the observedtidal current is quite complicated with the presence of seasonal thermocline. The observed tidal current may be divided into two parts, an averaged barotropic tide current and a variation tide current. A method for studying the vertical structure of tidal current is developed from the constitution and distribution of energy, and the vertical structure of the observed tide current in the North Huanghai Sea is studied on the basis of the method. The result shows that the reason why the energy of the tidal current is concentrated on the neighbourhood of the thermocline mainly lies in the internal tides i under certain conditions, the fact that the direction of the internal tide current above the thermocline is opposite to the one below the thermocline will be able to cause the rotary directions of the observed tidal current above and below the thermocline to be in opposite. The interaction between the averaged barotropic and the variation tide current plays an important role in forming the vertical structure of the tidal current, and it is mainly the interaction that results in the inho-mogeneous distribution of the tide current energy in the entire water column ; the ratio between the total energies of the internal tide current above the thermocline and the variation tide current in the entire water column is greater than the ratio between the total energies of that below the thermocline and the variation's. In a strong internal tide area such as the neighbourhood of Station L4, at diurnal tide frequency, the above-mentioned corresponding ratios are about 38. 82% and 29. 88%, respectively, and the energy of the internal tide current is about 68. 70%of the energy of the variation tide current; at semidiurnal tide frequency, the above-mentioned corresponding ratios are about 26. 61 % and 19. 73% , respectively, and the total internal tide current energy is about 46. 36% of the total variation tide current energy.展开更多
Supercapacitors,comprising electrical double-layer capacitors(EDLCs)and pseudocapa-citors,are widely acknowledged as high-power energy storage devices.However,their local structures and fundamental mechanisms remain p...Supercapacitors,comprising electrical double-layer capacitors(EDLCs)and pseudocapa-citors,are widely acknowledged as high-power energy storage devices.However,their local structures and fundamental mechanisms remain poorly understood,and suitable experimental techniques for investigation are also lacking.Recently,nuclear magnetic resonance(NMR)has emerged as a powerful tool for addressing these fundamental issues with high local sensitivity and non-invasiveness.In this paper,we first review the limi-tations of existing characterization methods and highlight the advantages of NMR in investigating mechanisms of supercapacitors.Subsequently,we introduce the basic prin-ciple of ring current effect,NMR-active nuclei,and various NMR techniques employed in exploring energy storage mechanisms including cross polarization(CP)magic angle spinning(MAS)NMR,multiple-quantum(MQ)MAS,two-dimensional exchange spec-troscopy(2D-EXSY)NMR,magnetic resonance imaging(MRI)and pulsed-field gradient(PFG)NMR.Based on this,recent progress in investigating energy storage mechanisms in EDLCs and pseudocapacitors through various NMR techniques is discussed.Finally,an outlook on future directions for NMR research in supercapacitors is offered.展开更多
The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect require...The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.展开更多
The lack of soft magnetic composites with high power density in MHz frequency range has become an obstacle in the efficient operation of the electrical and electronic equipments.Here,a promising method to increase the...The lack of soft magnetic composites with high power density in MHz frequency range has become an obstacle in the efficient operation of the electrical and electronic equipments.Here,a promising method to increase the cut-off frequency of iron-based soft magnetic composites to hundreds of MHz is reported.The cut-off frequency is increased from 10 MHz to 1 GHz by modulating the height of the ring,the distribution of particles,and the particle size.The mechanism of cut-off frequency and permeability is the coherent rotation of domain modulated by inhomogeneous field due to the eddy current effect.An empirical formula for the cut-off frequency in a magnetic ring composed of iron-based particles is established from experimental data.This work provides an effective approach to fabricate soft magnetic composites with a cut-off frequency in hundreds of MHz.展开更多
文摘BACKGROUND： Researches prove that the treatment of cerebral palsy by botulinus toxin （BTX-A） can improve effect and prolong effective duration. Current intensity is the important factor during injection. OBJECTIVE： To observe the changes of motor function and muscular intensity of children with spastic cerebral palsy after injecting BTX-A and analyze correlation between current intensity and effective duration. DESIGN： Cases control trial before and after nerves block SETTING： Capital University of Medical Sciences, China Rehabilitation Research Center PARTICIPANTS： From June 2002 to November 2004, 14 children with spastic cerebral palsy were treated by BTX-A block. All children were hospitalized in the Children Rehabilitation Department of China Rehabilitation Research Center. The children included 9 male and 5 female, and ranged from 4 to 13 years old, and average age was （6±2） years. Muscular tension ranged from grade 1 to grade 3. The diagnosis and the tape of cerebral palsy based on standard of the Fist Nationwide Cerebral Palsy Symposium, and all children were diagnosed with electroencephalogram （EEG）, CT and MRI, and permitted by their guardians. METHODS： （1） Locating and calculation： To locate block points by G6805-2A electro-therapeutic apparatus （Shanghai Huayi Electronic Instrument Plant） at the least stimulating current （continuous wave; impulse frequency; 2.667-83.333 Hz; current intensity： 0-6 mA; voltage： 6 V） to touch off muscles contraction. The current intensity of each point was recorded, and the average current intensity of each patient was calculated at the same time. （2） Dose of BTX-A： Basing upon the spastic degree and weight of patients, the dose was made certain： dose （IU）=（scores of Modified Ashworth Scale ＋2.5） xweight （kg）. The number of the block points was in all 4. The dose of injection ranged from 50 IU to 160 IU with the average of （73.6＋25.8） IU. The BTX-A was made by Lanzhou Institute of Biological Products, and each bottle contains 100 IU BTX-A. Muscular tension was evaluated by Modified Ashworth Scale. The scale ranged from grade 0 to grade 4, and the scores were from 0 to 4. The higher the scores were, the higher the muscular tension was. （3） Effect： Changes of muscular tension were evaluated by modified Ashworth Scale before and after block. Motor function was evaluated by Physician Rating Scale （PRS） before and after treatment. It contained Gait pattern, Hindfoot （ankle） position （stance-floor contact）, Hindfoot position （foot strike）, Knee position （degree of recurvation）, Crouch and Speed of gait. The scores ranged from 0 to 14. The higher the points were, the better the motor function was. （4） Effective duration： The duration was definited by the recovering of the Modified Ashworth Scale. （5） Statistic analysis： Firstly, the current intensity and the effect duration were analyzed by One-Sample Kolmogorov-Smirnov Test, the current intensity： Z= 0.456, P= 0.985, the effective duration： Z= 0.557, P= 0.915. Both data were normal distribution. Secondly, both data were analyzed by Linear Regression. The efficiency of the BTX-A block was analyzed by paired-samples t test. MAIN OUTCOME MEASURES： （1） Changes of motor function of muscular tension; （2） correlation between current intensity and effective duration. RESULTS： Fourteen children with spastic cerebral palsy were all involved in the final analysis. （1） Therapeutic effect： The average score of Ashworth scale after block was lower than that before block [（1.02±0.34） points vs. （2.12±0.48） points, t= 3.644, P〈 0.01]. The average score of RPS after block was higherthan that before block [（9.75±2.78） points vs. （6.16±0.58） points, t =13.222, P〈 0.01]. （2） Relation between the current intensity and the effective duration： The current intensity was （0.1857±0.0506） mA, and the effective duration was （26.36±4.48） weeks. The current intensity was negative correlation with effective duration （r = -0.775, P = 0.01 ）. CONCLUSION： （1） BTX-A occlusion can decrease muscular tension and improve motor function of lower limbs of children with spastic cerebral palsy. （2） The lower the current intensity is, the longer the effective duration is.
文摘The microplasma oxidation process of LY 12 Al alloy in Na2SiO3-KOH-NaAL2 system has been studied. The voltage-time curve of oxidation process is changed with the variation of current densities. The voltage breakdown and hardness of coating increase with increasing current density. The phase composition, morphologies, element and the distribution of ceramic coating are investigated by XRD, EPMA.
基金Project supported by the National Key Basic Research Program of China(Grant Nos.2015CB921000,2016YFA0300301,and 2017YFA0302902)the National Natural Science Foundation of China(Grant Nos.11674374 and 1474338)+5 种基金the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDB-SSW-SLH008)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB07020100 and XDB07030200)the Beijing Municipal Science and Technology Project(Grant No.Z161100002116011)the Fonds de la Recherche Scientifique–FNRS and the ARC Grant 13/18-08 for Concerted Research Actions,financed by the French Community of Belgium(Wallonia-Brussels Federation)Jérémy Brisbois acknowledges the support from F.R.S.–FNRS(Research Fellowship)The work of Alejandro V Silhanek is partially supported by PDR T.0106.16 of the F.R.S.–FNRS
文摘In this work,we discuss the origin of several anomalies present in the point-contact Andreev reflection spectra of（Li1-xFex）OHFeSe,LiTi2O4,and La2-xCexCuO4.While these features are similar to those stemming from intrinsic superconducting properties,such as Andreev reflection,electron-boson coupling,multigap superconductivity,d-wave and p-wave pairing symmetry,they cannot be accounted for by the modified Blonder–Tinkham–Klapwijk（BTK） model,but require to consider critical current effects arising from the junction geometry.Our results point to the importance of tracking the evolution of the dips and peaks in the differential conductance as a function of the bias voltage,in order to correctly deduce the properties of the superconducting state.
基金financially supported by the National Basic Research Program of China(2011CB610406)the Natural Science Foundation of Hei Longjiang Province(JC201209)the National Natural Science Foundation of China(51425402)
文摘The effect of excitation current intensity on the mechanical properties of ZL205 A castings solidified under a traveling magnetic field was studied. The results of the experiment indicate that the excitation current intensity of the traveling magnetic field has a great influence on the mechanical properties of the ZL205 A castings. When the excitation current intensity is 15 A, the tensile strength and elongation of ZL205 A alloy castings increase 27.2% and 67.7%, respectively, compared with those of the same alloy solidified under gravity. The improvement of mechanical properties is attributed to the decrease of micro-porosity in the alloy. Under the traveling magnetic field, the feeding pressure in the alloy melt before solidification can be enhanced due to the electromagnetic force. Moreover, the melt flow induced by the traveling magnetic field can decrease the temperature gradient. The feeding resistance will be increased because the temperature gradient decrease. So traveling magnetic field has an optimum effect on feeding.
基金funding from Conselho Nacional de Desenvolvimento Científico e Tecnológico(CNPq#403120/2012-8,#308723/2013-9,#449436/2014-4)Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES),Brazil
文摘Purines have a recognized importance as intercellular mes- sengers. These molecules play an important role in the de- velopment and maintenance of the central nervous system （CNS）, as well as in its response to pathological conditions. Both adenine and guanine-based purines can be released from astrocytes, where they play a relevant role as extracel- lular signaling molecules. Particularly, the nucleoside gua- nosine has been proposed as an extracellular molecule that regulates the response of CNS to damage. Following injury, this nucleoside attains high concentrations in the extracel- lular space, where it activates multiple signaling pathways.
基金supported by National Natural Science Foundation of China (No. 10175025)in part by the JSPS-CAS Core-University Program on Plasma and Nuclear Fusion
文摘Hugoniot relations of a two-dimensional axial shock with current and magnetic field in a cylindrical shock tube were investigated by a numerical method. The radial profiles of the magnetic field, electric current, pressures, flow velocities and temperatures between the up- and down-stream radial force-balanced plasma of the shock were revealed by numerical analysis. It is clearly found that the axial shock can lead to two effects： one is an inverse skin effect （i.e., the current density rises towards the center of the conductor）, the another is a reversed current effect which occurs near the edge and about a half radius. It is also found that the radial gradient of pressure, density and temperature all become very large near the center due to the axial shock.
基金supported by the National Natural Science Foundation of China (Grant No. 61934006)。
文摘An improved small-signal equivalent circuit of HBT concerning the AC current crowding effect is proposed in this paper. AC current crowding effect is modeled as a parallel RC circuit composed of Cbi and Rbi, with distributed base-collector junction capacitance also taken into account. The intrinsic portion is taken as a whole and extracted directly from the measured Sparameters in the whole frequency range of operation without any special test structures. An HBT device with a 2 × 20 μm^(2) emitter-area under three different biases were used to demonstrate the extraction and verify the accuracy of the equivalent circuit.
基金Supported by the National Natural Science Foundation of China under Grant No 11347002the National Magnetic Confinement Fusion Science Program of China under Grant No 2013GB111000+2 种基金the Outstanding Youth Fund of Hunan Province Education Department of China under Grant No 12B107the JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics under Grant No 11261140328the National Research Foundation 2012K2A2A6000443
文摘The effect of the wave accessibility condition on the lower hybrid cm＇rent drive in the experimental advanced superconductor Tokamak （EAST） plasma with H-mode operation is studied. Based on a simplified model, a mode conversion layer of the lower hybrid wave between the fast wave branch and the slow wave branch is proved to exist in the plasma periphery for typical EAST H-mode parameters. Under the framework of the lower hybrid wave simulation code （LSC）, the wave ray trajectory and the associated current drive are calculated numerically. The results show that the wave accessibility condition plays an important role on the lower hybrid current drive in EAST plasma. For wave rays with parallel refractive index n｜｜= 2.1 or n｜｜ = 2.5 launched from the outside midplane, the wave rays may penetrate the core plasma due to the toroida] geometry effect, while numerous reflections of the wave ray trajectories in the plasma periphery occur. However, low current drive efficiency is obtained. Meanwhile, the wave accessibility condition is improved if a higher confined magnetic field is applied. The simulation results show that for plasma parameters under present EAST H-mode operation, a significant lower hybrid wave current drive could be obtained for the wave spectrum with peak value n｜｜ = 2.1 if a toroidal magnetic field BT =2.5 T is applied.
基金supported in part by the National Natural Science Foundation of China(Grant No.92060114)in part by the Sichuan Science and Technology Program(Nos.2022YFS0524 and 2022YFG0044).
文摘It is known that eddy current effect has a great influence on magnetic flux leakage testing(MFL).Usually,contacttype encoder wheels are used to measure MFL testing speed to evaluate the effect and further compensate testing signals.This speed measurement method is complicated,and inevitable abrasion and occasional slippage will reduce the measurement accuracy.In order to solve this problem,based on eddy current effect due to the relative movement,a speed measurement method is proposed,which is contactless and simple.In the high-speed MFL testing,eddy current induced in the specimen will cause an obvious modification to the applied field.This modified field,which is measured by Hall sensor,can be utilized to reflect the moving speed.Firstly,the measurement principle is illustrated based on Faraday’s law.Then,dynamic finite element simulations are conducted to investigate the modified magnetic field distribution.Finally,laboratory experiments are performed to validate the feasibility of the proposed method.The results show that Bmz(r1)and Bmx(r2)have a linear relation with moving speed,which could be used as an alternative measurement parameter.
文摘The article theoretically studied the charge-exchange effects on space charge limitedelectron and ion current densities of non-relativistic one-dimensional slab ion diode, and comparedwith those of without charge exchange.
文摘Three-dimensional thermo-electrical finite element analyses were conducted to simulate the current density and temperature distributions in solder bump joints with different pad geometries.The effects of pad thickness,diameter and shape on current density and temperate distributions were investigated respectively.It was found that pads with larger thickness or/and diameter could reduce current density and temperature in solder bump significantly.Pad shapes affected the current density and temperature distributions in solder bumps.The relatively low current density and temperature didn＇t occur in the bump joint with traditional rounded pad but occurred in bump joints with octagonal and nonagonal pads respectively.Therefore,optimized pad geometry may be designed to alleviate the current crowding effect and reduce the bump temperature,and therefore delay electromigration failure and increase the mean-time-to-failure.
基金Supported by National Natural Science Foundation of China(Nos.91226202,91426304)CAS Interdisciplinary Innovation Team Project
文摘The spark plasma sintering（SPS） method was used to study the mechanism of reaction interface between Zr and Ti3AlC2 with electric current going through it. It was found that electric current greatly reduced the bonding temperature of Zr and Ti3AlC2. By the micro-structure analysis of the interface through SEM/EDS, it was found that Al atoms diffused from the Ti3AlC2 substrate into the Zr side and reacted with Zr to form the Zr-Al compounds at the interface, which is the strengthening mechanism of Ti3AlC2-Zr bonding. The thickness of reaction layers（Zr-Al alloy） was from 0.879 to 13.945 mm depending on different sintering condition. Current direction, heating rate, soaking time, pulse patterns all influenced the diffusion of Al atoms which affected the joining quality of Zr and Ti3AlC2.
基金Supported by the Program of Fusion Reactor Physics and Digital Tokamak with the Chinese Academy of Sciences'One-Three Five'Strategic Planningthe JSPS-NRF-NSFC A3 Foresight Program in the Field of Plasma Physics(NSFC No 11261140328 and NRF No 2012K2A2A6000443)+1 种基金the National ITER Program of China under Grant No 2015GB101003the National Natural Science Foundation of China under Grant Nos 11405215,11475223 and 11505236
文摘The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current are studied via particle-in-cell simulations. It is found that the energetic ions and background ions can be treated separately as different species, and they satisfy their individual Bohm criterion at the sheath edge. It is shown that the energetic ions can significantly affect the ion saturation current if their concentration is greater than root T-e/(gamma T-i2(i2)), where T-e is the electron temperature, and gamma(i2) and T-i2 represent the polytropic coefficient and temperature of energetic ions, respectively. As a result, the floating potential and the I-V characteristic profile are strongly influenced by the energetic ions. When the energetic ion current dominates the ion saturation current, an analysis of the ion saturation current will yield the energetic ion temperature rather than the electron temperature.
文摘Compared with the conventionally used i=iosinωt alternating current, using asymmetric triangular and pulse wave as input signals can greatly enhance the incision's sensitivity of 'dE/dt-E'oscillogram.
基金the Joint Guidance Project of Natural Science Foundation of Heilongjiang Province(No.LH2021F008)。
文摘Aiming at the approximate measurement of magnetic rotation angle in optical current sensor based on light intensity detection mode,this paper proposes a current measurement method based on triangular constant transformation to reconstruct magnetic rotation angle,so as to avoid the large current measurement error caused by the approximate measurement of the magnetic rotation angle.By extracting the direct current(DC)component and the alternating current(AC)component of the light intensity signal detected by the photoelectric detector(PD),the sine signal containing the magnetic rotation angle is directly obtained by dividing the two components,and then the triangular identity transformation method is used to linearly demodulate the magnetic rotation angle and reconstruct the current waveform.The experimental results show that the relative error of current measurement does not exceed 1.40%in the current range of 0.05—0.50 A,which is less than the approximate linear measurement(ALM)method,and the magnetic rotation angle and the current have a good linear relationship.
基金Supported by the National Natural Science Foundation of China under Grant No 11372096the Research Fund for the Doctoral Program of Higher Education of China
文摘The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ （REBCO, RE： rare earth） films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries （GBs） in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data.
基金The project supported by National Natural science Foundation of China
文摘The tidal current is generally predominant in China's offshore areas. The vertical structure of the observedtidal current is quite complicated with the presence of seasonal thermocline. The observed tidal current may be divided into two parts, an averaged barotropic tide current and a variation tide current. A method for studying the vertical structure of tidal current is developed from the constitution and distribution of energy, and the vertical structure of the observed tide current in the North Huanghai Sea is studied on the basis of the method. The result shows that the reason why the energy of the tidal current is concentrated on the neighbourhood of the thermocline mainly lies in the internal tides i under certain conditions, the fact that the direction of the internal tide current above the thermocline is opposite to the one below the thermocline will be able to cause the rotary directions of the observed tidal current above and below the thermocline to be in opposite. The interaction between the averaged barotropic and the variation tide current plays an important role in forming the vertical structure of the tidal current, and it is mainly the interaction that results in the inho-mogeneous distribution of the tide current energy in the entire water column ; the ratio between the total energies of the internal tide current above the thermocline and the variation tide current in the entire water column is greater than the ratio between the total energies of that below the thermocline and the variation's. In a strong internal tide area such as the neighbourhood of Station L4, at diurnal tide frequency, the above-mentioned corresponding ratios are about 38. 82% and 29. 88%, respectively, and the energy of the internal tide current is about 68. 70%of the energy of the variation tide current; at semidiurnal tide frequency, the above-mentioned corresponding ratios are about 26. 61 % and 19. 73% , respectively, and the total internal tide current energy is about 46. 36% of the total variation tide current energy.
基金supported by the National Natural Science Foundation of China(Grant No.22075064)National Key Laboratory Projects(No.SYSKT20230056).
文摘Supercapacitors,comprising electrical double-layer capacitors(EDLCs)and pseudocapa-citors,are widely acknowledged as high-power energy storage devices.However,their local structures and fundamental mechanisms remain poorly understood,and suitable experimental techniques for investigation are also lacking.Recently,nuclear magnetic resonance(NMR)has emerged as a powerful tool for addressing these fundamental issues with high local sensitivity and non-invasiveness.In this paper,we first review the limi-tations of existing characterization methods and highlight the advantages of NMR in investigating mechanisms of supercapacitors.Subsequently,we introduce the basic prin-ciple of ring current effect,NMR-active nuclei,and various NMR techniques employed in exploring energy storage mechanisms including cross polarization(CP)magic angle spinning(MAS)NMR,multiple-quantum(MQ)MAS,two-dimensional exchange spec-troscopy(2D-EXSY)NMR,magnetic resonance imaging(MRI)and pulsed-field gradient(PFG)NMR.Based on this,recent progress in investigating energy storage mechanisms in EDLCs and pseudocapacitors through various NMR techniques is discussed.Finally,an outlook on future directions for NMR research in supercapacitors is offered.
基金supported by the National Key R&D Program of China(Grant No.2020YFC2200500)the Key Laboratory of Tian Qin Project(Sun Yat-sen University),Ministry of Education+1 种基金the National Natural Science Foundation of China(Grant Nos.12075325,12005308,and 11605065)the Doctoral Research Foundation Project of Hubei University of Arts and Science(Grant No.kyqdf2059017)。
文摘The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.
基金the National Natural Science Foun-dation of China(Grant Nos.91963201 and 12174163)the 111 Project(Grant No.B20063).
文摘The lack of soft magnetic composites with high power density in MHz frequency range has become an obstacle in the efficient operation of the electrical and electronic equipments.Here,a promising method to increase the cut-off frequency of iron-based soft magnetic composites to hundreds of MHz is reported.The cut-off frequency is increased from 10 MHz to 1 GHz by modulating the height of the ring,the distribution of particles,and the particle size.The mechanism of cut-off frequency and permeability is the coherent rotation of domain modulated by inhomogeneous field due to the eddy current effect.An empirical formula for the cut-off frequency in a magnetic ring composed of iron-based particles is established from experimental data.This work provides an effective approach to fabricate soft magnetic composites with a cut-off frequency in hundreds of MHz.
