Heterojunction has been widely used in vibration-driven piezocatalysis for enhanced charges separation,while the weak interfaces seriously affect the efficiency during mechanical deformations due to prepared by tradit...Heterojunction has been widely used in vibration-driven piezocatalysis for enhanced charges separation,while the weak interfaces seriously affect the efficiency during mechanical deformations due to prepared by traditional step-by-step methods.Herein,the intimate contact interfaces with shared S atoms are ingeniously constructed in SnS_(2)/SnS anchored on porous carbon by effective interface engineering,which is in-situ derived from temperature-dependent self-transformation of SnS_(2).Benefiting from intimate contact interfaces,the piezoelectricity is remarkably improved due to the larger interfacial dipole moment caused by uneven distribution of charges.Importantly,vibration-induced piezoelectric polarization field strengthens the interfacial electric field to further promote the separation and migration of charges.The dynamic charges then transfer in porous carbon with high conductivity and adsorption for significantly improved piezocatalytic activity.The degradation efficiency of bisphenol A(BPA)is 6.3 times higher than SnS_(2) and H_(2) evolution rate is increased by 3.8 times.Compared with SnS_(2)/SnS prepared by two-step solvothermal method,the degradation efficiency of BPA and H2 evolution activity are increased by 3 and 2 times,respectively.It provides a theoretical guidance for developing various multiphase structural piezocatalyst with strong interface interactions to improve the piezocatalytic efficiency.展开更多
Copper is susceptible to producing corrosion problems in corrosive environments, which leads to serious safety problems. Thus, investigating the corrosion behavior of copper is of great significance. The effects of ro...Copper is susceptible to producing corrosion problems in corrosive environments, which leads to serious safety problems. Thus, investigating the corrosion behavior of copper is of great significance. The effects of rotating electromagnetic field on corrosion behavior of T2 copper in 3.5% sodium chloride solution with electrochemical measurements were investigated. The results showed that rotating electromagnetic field changed properties of 3.5% sodium chloride solution by increasing the values of temperature and pH and decreasing the values of conductivity and dissolved oxygen. The rotating electromagnetic field improved the corrosion resistance of T2 copper. The corrosion products of T2 copper in treated 3.5% sodium chloride solution were composed of Cu20 and CuCl. The low corrosion rate of T2 copper was resulted from the decrease of dissolved oxygen in 3.5% sodium chloride solution treated by rotating electromagnetic field.展开更多
A new method for synthesizing Mg-Al hydrotalcite conversion coating on AZ91D Mg alloy was developed by the application of electric field (EF). By using EF technique, the formation time of the coating can be signific...A new method for synthesizing Mg-Al hydrotalcite conversion coating on AZ91D Mg alloy was developed by the application of electric field (EF). By using EF technique, the formation time of the coating can be significantly reduced. The SEM results indicate that a continuous and compact Mg-Al hydrotalcite coating is formed on the surface of Mg alloy after short time EF treatment. However, a long time treatment would make the coating partially exfoliate. The corrosion current density (Jcor ) of the coated sample (EF1+1 h) is approximately two orders of magnitude lower than that of Mg alloy substrate. The test of electrochemical impedance spectroscopy (EIS) and immersion corrosion also suggest that the coating can effectively protect Mg alloy against corrosion.展开更多
The ocean surface currents are reconstructed from the satellite remote sensing data containing altimeter-derived sea surface height and QuikSCAT satellite-derived wind data. Based on the method proposed by Lagerloef, ...The ocean surface currents are reconstructed from the satellite remote sensing data containing altimeter-derived sea surface height and QuikSCAT satellite-derived wind data. Based on the method proposed by Lagerloef, a global weekly 0.5°×0.5°ocean surface current product was obtained over the period 2000 - 2008 by combining the geostrophic currents estimated from sea surface height with Ekman current estimated from the wind stress. Particularly, weight functions were introduced when calculating the Ekman currents to eliminate the discontinuity near 25°S and 25°N. These satellite-derived currents have been compared with TAO current meter and the SCUD product, respectively. The comparison showed that satellite-derived currents not only could capture the characteristics of ocean surface currents but also had high accuracy and reliability. The result showed that this innovatory method was effective.展开更多
With the reform of agriculture, family farms have become hot spots in the reform of agricultural management system. Taking Rudong County of Jiangsu Province for an example, the land transfer performance of family farm...With the reform of agriculture, family farms have become hot spots in the reform of agricultural management system. Taking Rudong County of Jiangsu Province for an example, the land transfer performance of family farms was evalu- ated using the first hand data from field investigation by building an index system for comprehensive performance evaluation of family farm land transfer covering three dimensions of economy, society and ecology. The results show that land transfer in family farm mode has realized the scale management of land, enhanced the agri- cultural level of science and technology, effectively promoted the structural adjust- ment of agriculture and income increase of farmers, advanced the development of eco-agriculture, and achieved good economic and social performances. However, in the development process of family farms, inputs of agro-chemicals, fertilizers and other agro-products have brought about the eco-environmental problems, which are still worth noting.展开更多
A meshless simulation system is presented for elastic deformation driven by skeleton in this paper. In this system, we propose a new method for calculating node rotation while applying a similar technique with stiffne...A meshless simulation system is presented for elastic deformation driven by skeleton in this paper. In this system, we propose a new method for calculating node rotation while applying a similar technique with stiffness warping to tackle the nonlinear large deformation. In our method, all node rotations are evaluated from sampling points in attached skeleton by con- structing and solving the diffusion partial differential equation. The experiments indicated that the method can enhance the sta- bility of the dynamics and avoid fussy sub-step calculation in static deformation edition. Moreover, rational deformation results for the area around the skeleton joints can be simulated without user interaction by adopting the simplified technique.展开更多
Conventional permanent magnet synchronous machine (PMSM) has the problem of large stator copper loss and narrow speed range. To solve this problem, an interior composite-rotor controllable-flux PMSM adaptive to multi-...Conventional permanent magnet synchronous machine (PMSM) has the problem of large stator copper loss and narrow speed range. To solve this problem, an interior composite-rotor controllable-flux PMSM adaptive to multi-polar is proposed. This machine has the characteristics of low stator copper loss and wide-speed operation. The half-radial-set and half-tangential-set permanent magnets (PMs) are NdFeB that has high remanent flux density and high coercive force. The tangential-set PMs are AlNiCo that has high remanent flux density and low coercive force. By applying the pulse of d-axis stator current i_d, the magnetized intensity and direction of AlNiCo can be controlled. The flux created by NdFeB is repelled to stator and air-gap PM-flux is intensified, or is partially bypassed by AlNiCo in the rotor, so the air-gap PM-flux is weakened. The internal magnetic field distribution in two ultra magnetized situations is analyzed by finite element method. The dimension of PMs and magnetic structure are demonstrated. Especially when the q-axis magnetic resistance is larger and the q-axis inductance is smaller, the result of flux-weakening is better and the influence of armature reaction on air-gap PM-flux is weakened.展开更多
A new approach for transforming the cultured cells of wheat(Triticum aestivum L. cv. Ganmai 8) was developed using Agrobacterium tumefaciens. The features of the optimum procedure were: (a) both combined synthetic sig...A new approach for transforming the cultured cells of wheat(Triticum aestivum L. cv. Ganmai 8) was developed using Agrobacterium tumefaciens. The features of the optimum procedure were: (a) both combined synthetic signal molecules and multiple natural extracts from susceptible plants were used to pretreat the primary vigorous Agrobacterium(PVA) cells for approximately 16 h; (b) the gyratory magnetic field condition was used during cocultivation; (c) the cocultivating period and selecting condition were modified; (d) the recipient cells were at exuberant metabolism and active division while infected with Agrobacterium. Both neomycin phosphotransferase and nopaline synthase assays demonstrated the expression of NPT II and NOS genes, located on the T-DNA segment of chimaeric plasmid pGV3850::1103neo, in transformed wheat cell colonies by adopting the techniques of dot blot, ndPAGE or high voltage paper electrophoresis. Integration of the foreign genes into wheat genome was confirmed by Southern blot hybridization. Moreover, a relatively rational method was described for the estimation of transformation frequencies from cultured cell levels.展开更多
We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves n...We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves no chronological product. The spin vectors (mean values of the spin operators) are obtained as explicit functions of time in the most general case. A series of cyclic solutions are presented. The nonadiabatic geometric phases of these cyclic solutions are caleulated, and are expressed in terms of the solid angle subtended by the closed trace of thc total spin vector, as well as in terms of those of the individual spins.展开更多
We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-p...We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-photon Jaynes-Cummings model under certain conditions.展开更多
Based on a new semi empirical analytical method, namely equivalent doping transformation, the breakdown voltage and the peak field of the epitaxial diffused punch through junction have been obtained. The basic prin...Based on a new semi empirical analytical method, namely equivalent doping transformation, the breakdown voltage and the peak field of the epitaxial diffused punch through junction have been obtained. The basic principle of this method is introduced and a set of breakdown voltage and peak field plots are provided for the optimum design of the low voltage power devices. It shows that the analytical results coincide with the previous numerical simulation well.展开更多
We theoretically analyze the reflection spectra of the fiber Bragg gratings in the quadratic strain field,and resolve the numerical value with transfer matrix method.When the value of pressure is changed,we can obtain...We theoretically analyze the reflection spectra of the fiber Bragg gratings in the quadratic strain field,and resolve the numerical value with transfer matrix method.When the value of pressure is changed,we can obtain diverse reflection spectra of the fiber Bragg gratings,which is in good accordance with the experimental results.展开更多
Methane conversion was studied with electric field enhanced plasma (EFEP) technique at the atmosphere pressure and low temperature ranging from 323 K to 373 K. The conversion of methane is up to 60%-80%. The kinetics ...Methane conversion was studied with electric field enhanced plasma (EFEP) technique at the atmosphere pressure and low temperature ranging from 323 K to 373 K. The conversion of methane is up to 60%-80%. The kinetics of methane conversion was studied using naicroreactor. The reaction model of power function type was obtained as: r = 90.99exp (-26980/RT)C0226A(mol·m-3·s-1). The global kinetics parameters were calculated by the variable simple-pure shape method. The calculating results are in good agreement with experimental data.展开更多
A sound speed profile plays an important role in shallow water sound propagation.Concurrent with in-situ measurements,many inversion methods,such as matched-field inversion,have been put forward to invert the sound sp...A sound speed profile plays an important role in shallow water sound propagation.Concurrent with in-situ measurements,many inversion methods,such as matched-field inversion,have been put forward to invert the sound speed profile from acoustic signals.However,the time cost of matched-field inversion may be very high in replica field calculations.We studied the feasibility and robustness of an acoustic tomography scheme with matched-field processing in shallow water,and described the sound speed profile by empirical orthogonal functions.We analyzed the acoustic signals from a vertical line array in ASIAEX2001 in the East China Sea to invert sound speed profiles with estimated empirical orthogonal functions and a parallel genetic algorithm to speed up the inversion.The results show that the inverted sound speed profiles are in good agreement with conductivity-temperature-depth measurements.Moreover,a posteriori probability analysis is carried out to verify the inversion results.展开更多
To understand the solidification behavior of austenitic stainless steel in rotary electromagnetic-field, the influence of low-frequency rotary electromagnetic-field on solidification structure of austenitic stainless ...To understand the solidification behavior of austenitic stainless steel in rotary electromagnetic-field, the influence of low-frequency rotary electromagnetic-field on solidification structure of austenitic stainless steel in horizontal continuous casting was investigated based on industrial experiments. The results show that the solidification structure of austenitic stainless steel can be remarkably refined, the central porosity and shrinkage cavity can be remarkably decreased, and the equiaxed grains zone are enlarged by means of application of appropriate low-frequency electromagnetic-field parameters. The industrial trials verify that the stirring intensity of austenitic stainless steel should be higher compared with that of plain carbon steel. Electromagnetic stirring affects the macrostructure even if the average magnetic flux density of the electromagnetic stirring reaches 90 mT (amplitude reaches 141 mT) with the frequency of 3-4 Hz. Due to a higher viscosity, rotating speed of molten stainless steel is 20%-30% lower than that of molten carbon steel in the same magnetic flux density.展开更多
The geometric phase of the bipartite Heisenberg spin-1/2 system with one spin driven by rotating magnetic field is investigated. It is found that in the one-site drive case, the intersubsystem coupling can be equivale...The geometric phase of the bipartite Heisenberg spin-1/2 system with one spin driven by rotating magnetic field is investigated. It is found that in the one-site drive case, the intersubsystem coupling can be equivalent to a static quasi-magnetic field in the parameter space. This perspective has satisfactorily explained the irregular asymptote effect of geometric phase. We discuss the property of the two-site magnetic drive spin system and discover that a stationary state with no geometric phase shift is generated.展开更多
The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial ...The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial domains.The transformation method in the wavenumber domain has simpler processing expression and higher processing effi ciency than in the spatial domain;however,they are unstable at low latitude.In this paper,the conclusion that the sum is 0 of two vertical magnetic fi eld components(magnetization inclinations are also perpendicular)in 2D is used for the 3D transformation of the magnetization direction and the magnetic field component.In addition,the transformation method at low latitudes based on vertical relationship(VMT)is proposed,which is an iterative algorithm that converts the transformation of the magnetization direction and the magnetic field component at the low latitude into the high latitude.This method restrains the instability of transformation of constant and variable magnetization direction and magnetic fi eld components in low latitudes.The accuracy,stability,and practicality are verifi ed from synthetic models and real data.展开更多
The longitudinal-random-fieM mixed Ising model consisting of arbitrary spin values has been studied by the use of an effective field theory with correlations (EFT). The phase diagrams of systems with mixed spins: ...The longitudinal-random-fieM mixed Ising model consisting of arbitrary spin values has been studied by the use of an effective field theory with correlations (EFT). The phase diagrams of systems with mixed spins: σ = 1/2, S = 1; σ = 1/2, S = 3/2 are plotted. Not only the discontinuity at T = 0 K, is found when both longitudinal fields are trimodal distributed, but also the trieritical behavior is observed in these phase diagrams between the bimodal and trimodal distributions of longitudinal fields, which is different from the single-spin one. The appearance of tricritical point is independent of the coordination number and spin values.展开更多
In this letter, we have studied the influence of the external magnetic fields on tunneling of the spin-1 Bose condensate. We find that the population transfer between spin-0 and spin-±1 exhibits the step structur...In this letter, we have studied the influence of the external magnetic fields on tunneling of the spin-1 Bose condensate. We find that the population transfer between spin-0 and spin-±1 exhibits the step structure under the external cosinusoidal magnetic field and a combination of static and cosinusoidal one, respectively. Compared with the longitudinal component of the external magnetic field, the smaller the transverse component of the magnetic field is, the larger the time scale of exhibiting the step structure does. The tunneling current may exhibit periodically oscillation behavior when the ratio of the transverse component of the magnetic field is smaller than that of the longitudinal component, otherwise it exhibits a damply oscillating behavior. This means that the dynamical spin localization can be adjusted by the external magnetic fields.展开更多
文摘Heterojunction has been widely used in vibration-driven piezocatalysis for enhanced charges separation,while the weak interfaces seriously affect the efficiency during mechanical deformations due to prepared by traditional step-by-step methods.Herein,the intimate contact interfaces with shared S atoms are ingeniously constructed in SnS_(2)/SnS anchored on porous carbon by effective interface engineering,which is in-situ derived from temperature-dependent self-transformation of SnS_(2).Benefiting from intimate contact interfaces,the piezoelectricity is remarkably improved due to the larger interfacial dipole moment caused by uneven distribution of charges.Importantly,vibration-induced piezoelectric polarization field strengthens the interfacial electric field to further promote the separation and migration of charges.The dynamic charges then transfer in porous carbon with high conductivity and adsorption for significantly improved piezocatalytic activity.The degradation efficiency of bisphenol A(BPA)is 6.3 times higher than SnS_(2) and H_(2) evolution rate is increased by 3.8 times.Compared with SnS_(2)/SnS prepared by two-step solvothermal method,the degradation efficiency of BPA and H2 evolution activity are increased by 3 and 2 times,respectively.It provides a theoretical guidance for developing various multiphase structural piezocatalyst with strong interface interactions to improve the piezocatalytic efficiency.
基金Projects(51207031,51177022)supported by the National Natural Science Foundation of ChinaProject(2013M541368)supported by the China Postdoctoral Science Foundation+1 种基金Project(BS2011NJ002)supported by the Promotive Research Fund for Excellent Young and Middle-Aged Scientists of Shandong Province,ChinaProject(2008DFR60340)supported by the International Science and Technology Cooperation of China
文摘Copper is susceptible to producing corrosion problems in corrosive environments, which leads to serious safety problems. Thus, investigating the corrosion behavior of copper is of great significance. The effects of rotating electromagnetic field on corrosion behavior of T2 copper in 3.5% sodium chloride solution with electrochemical measurements were investigated. The results showed that rotating electromagnetic field changed properties of 3.5% sodium chloride solution by increasing the values of temperature and pH and decreasing the values of conductivity and dissolved oxygen. The rotating electromagnetic field improved the corrosion resistance of T2 copper. The corrosion products of T2 copper in treated 3.5% sodium chloride solution were composed of Cu20 and CuCl. The low corrosion rate of T2 copper was resulted from the decrease of dissolved oxygen in 3.5% sodium chloride solution treated by rotating electromagnetic field.
基金Project(12KJB430007)supported by the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province,ChinaProjects(CKJB201203,CKJA201202)supported by the Innovation Fund of Nanjing Institute of Technology ChinaProject(201311276001Z)supported by the Innovative Foundation Project for Student of Nanjing Institute of Technology,China
文摘A new method for synthesizing Mg-Al hydrotalcite conversion coating on AZ91D Mg alloy was developed by the application of electric field (EF). By using EF technique, the formation time of the coating can be significantly reduced. The SEM results indicate that a continuous and compact Mg-Al hydrotalcite coating is formed on the surface of Mg alloy after short time EF treatment. However, a long time treatment would make the coating partially exfoliate. The corrosion current density (Jcor ) of the coated sample (EF1+1 h) is approximately two orders of magnitude lower than that of Mg alloy substrate. The test of electrochemical impedance spectroscopy (EIS) and immersion corrosion also suggest that the coating can effectively protect Mg alloy against corrosion.
基金supported by the National Natural Science Foundation of China(No.41306010,41276088 and 41206002)
文摘The ocean surface currents are reconstructed from the satellite remote sensing data containing altimeter-derived sea surface height and QuikSCAT satellite-derived wind data. Based on the method proposed by Lagerloef, a global weekly 0.5°×0.5°ocean surface current product was obtained over the period 2000 - 2008 by combining the geostrophic currents estimated from sea surface height with Ekman current estimated from the wind stress. Particularly, weight functions were introduced when calculating the Ekman currents to eliminate the discontinuity near 25°S and 25°N. These satellite-derived currents have been compared with TAO current meter and the SCUD product, respectively. The comparison showed that satellite-derived currents not only could capture the characteristics of ocean surface currents but also had high accuracy and reliability. The result showed that this innovatory method was effective.
文摘With the reform of agriculture, family farms have become hot spots in the reform of agricultural management system. Taking Rudong County of Jiangsu Province for an example, the land transfer performance of family farms was evalu- ated using the first hand data from field investigation by building an index system for comprehensive performance evaluation of family farm land transfer covering three dimensions of economy, society and ecology. The results show that land transfer in family farm mode has realized the scale management of land, enhanced the agri- cultural level of science and technology, effectively promoted the structural adjust- ment of agriculture and income increase of farmers, advanced the development of eco-agriculture, and achieved good economic and social performances. However, in the development process of family farms, inputs of agro-chemicals, fertilizers and other agro-products have brought about the eco-environmental problems, which are still worth noting.
基金Project supported by the National Basic Research Program (973) of China (No. 2002CB312102) and the National Natural Science Foun-dation of China (Nos. 60021201, 60333010 and 60505001)
文摘A meshless simulation system is presented for elastic deformation driven by skeleton in this paper. In this system, we propose a new method for calculating node rotation while applying a similar technique with stiffness warping to tackle the nonlinear large deformation. In our method, all node rotations are evaluated from sampling points in attached skeleton by con- structing and solving the diffusion partial differential equation. The experiments indicated that the method can enhance the sta- bility of the dynamics and avoid fussy sub-step calculation in static deformation edition. Moreover, rational deformation results for the area around the skeleton joints can be simulated without user interaction by adopting the simplified technique.
基金Supported by Natural Science Foundation of China(No.50677042).
文摘Conventional permanent magnet synchronous machine (PMSM) has the problem of large stator copper loss and narrow speed range. To solve this problem, an interior composite-rotor controllable-flux PMSM adaptive to multi-polar is proposed. This machine has the characteristics of low stator copper loss and wide-speed operation. The half-radial-set and half-tangential-set permanent magnets (PMs) are NdFeB that has high remanent flux density and high coercive force. The tangential-set PMs are AlNiCo that has high remanent flux density and low coercive force. By applying the pulse of d-axis stator current i_d, the magnetized intensity and direction of AlNiCo can be controlled. The flux created by NdFeB is repelled to stator and air-gap PM-flux is intensified, or is partially bypassed by AlNiCo in the rotor, so the air-gap PM-flux is weakened. The internal magnetic field distribution in two ultra magnetized situations is analyzed by finite element method. The dimension of PMs and magnetic structure are demonstrated. Especially when the q-axis magnetic resistance is larger and the q-axis inductance is smaller, the result of flux-weakening is better and the influence of armature reaction on air-gap PM-flux is weakened.
文摘A new approach for transforming the cultured cells of wheat(Triticum aestivum L. cv. Ganmai 8) was developed using Agrobacterium tumefaciens. The features of the optimum procedure were: (a) both combined synthetic signal molecules and multiple natural extracts from susceptible plants were used to pretreat the primary vigorous Agrobacterium(PVA) cells for approximately 16 h; (b) the gyratory magnetic field condition was used during cocultivation; (c) the cocultivating period and selecting condition were modified; (d) the recipient cells were at exuberant metabolism and active division while infected with Agrobacterium. Both neomycin phosphotransferase and nopaline synthase assays demonstrated the expression of NPT II and NOS genes, located on the T-DNA segment of chimaeric plasmid pGV3850::1103neo, in transformed wheat cell colonies by adopting the techniques of dot blot, ndPAGE or high voltage paper electrophoresis. Integration of the foreign genes into wheat genome was confirmed by Southern blot hybridization. Moreover, a relatively rational method was described for the estimation of transformation frequencies from cultured cell levels.
文摘We study the Hcisenberg moder under the influence of a rotating magnetic field. By using a time- dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves no chronological product. The spin vectors (mean values of the spin operators) are obtained as explicit functions of time in the most general case. A series of cyclic solutions are presented. The nonadiabatic geometric phases of these cyclic solutions are caleulated, and are expressed in terms of the solid angle subtended by the closed trace of thc total spin vector, as well as in terms of those of the individual spins.
文摘We investigate the squeezing properties of the cavity field in the degenerate two-photon Jaynes Cummings model. Compared with the one-photon Jaynes-Cummings model, the squeezing is more pronounced in the case of two-photon Jaynes-Cummings model under certain conditions.
文摘Based on a new semi empirical analytical method, namely equivalent doping transformation, the breakdown voltage and the peak field of the epitaxial diffused punch through junction have been obtained. The basic principle of this method is introduced and a set of breakdown voltage and peak field plots are provided for the optimum design of the low voltage power devices. It shows that the analytical results coincide with the previous numerical simulation well.
基金Supported by the National Natural Science Foundation of China(60577018) Science and Technology Innovation Foundation of Nankai University and the Opening Project (2005-06) of KeyLaboratory of Optoelectronic Information Science and Technolo-gy ,Ministry of Education,China .
文摘We theoretically analyze the reflection spectra of the fiber Bragg gratings in the quadratic strain field,and resolve the numerical value with transfer matrix method.When the value of pressure is changed,we can obtain diverse reflection spectra of the fiber Bragg gratings,which is in good accordance with the experimental results.
基金Supported by the National Natural Science Foundation of China (No. 29776037) Research Foundation of SINOPEC (No.X500005).
文摘Methane conversion was studied with electric field enhanced plasma (EFEP) technique at the atmosphere pressure and low temperature ranging from 323 K to 373 K. The conversion of methane is up to 60%-80%. The kinetics of methane conversion was studied using naicroreactor. The reaction model of power function type was obtained as: r = 90.99exp (-26980/RT)C0226A(mol·m-3·s-1). The global kinetics parameters were calculated by the variable simple-pure shape method. The calculating results are in good agreement with experimental data.
基金Supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (No.KZCX1-YW-12-02)the National Natural Science Foundation of China (Nos.10974218,10734100)
文摘A sound speed profile plays an important role in shallow water sound propagation.Concurrent with in-situ measurements,many inversion methods,such as matched-field inversion,have been put forward to invert the sound speed profile from acoustic signals.However,the time cost of matched-field inversion may be very high in replica field calculations.We studied the feasibility and robustness of an acoustic tomography scheme with matched-field processing in shallow water,and described the sound speed profile by empirical orthogonal functions.We analyzed the acoustic signals from a vertical line array in ASIAEX2001 in the East China Sea to invert sound speed profiles with estimated empirical orthogonal functions and a parallel genetic algorithm to speed up the inversion.The results show that the inverted sound speed profiles are in good agreement with conductivity-temperature-depth measurements.Moreover,a posteriori probability analysis is carried out to verify the inversion results.
基金Project(CSTC2007BB4216) supported by the Natural Science Foundation of Chongqing,China
文摘To understand the solidification behavior of austenitic stainless steel in rotary electromagnetic-field, the influence of low-frequency rotary electromagnetic-field on solidification structure of austenitic stainless steel in horizontal continuous casting was investigated based on industrial experiments. The results show that the solidification structure of austenitic stainless steel can be remarkably refined, the central porosity and shrinkage cavity can be remarkably decreased, and the equiaxed grains zone are enlarged by means of application of appropriate low-frequency electromagnetic-field parameters. The industrial trials verify that the stirring intensity of austenitic stainless steel should be higher compared with that of plain carbon steel. Electromagnetic stirring affects the macrostructure even if the average magnetic flux density of the electromagnetic stirring reaches 90 mT (amplitude reaches 141 mT) with the frequency of 3-4 Hz. Due to a higher viscosity, rotating speed of molten stainless steel is 20%-30% lower than that of molten carbon steel in the same magnetic flux density.
基金The project supported by National Natural Science Foundation of China under Grant No. 20376054
文摘The geometric phase of the bipartite Heisenberg spin-1/2 system with one spin driven by rotating magnetic field is investigated. It is found that in the one-site drive case, the intersubsystem coupling can be equivalent to a static quasi-magnetic field in the parameter space. This perspective has satisfactorily explained the irregular asymptote effect of geometric phase. We discuss the property of the two-site magnetic drive spin system and discover that a stationary state with no geometric phase shift is generated.
基金supported by the subject “Study on the Comprehensive Processing and Interpretation Method and Software Development for Aerial Geophysics (No. 2017YFC0602202)” from National major Research and Development Project of China (No. 2017YFC0602200)。
文摘The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial domains.The transformation method in the wavenumber domain has simpler processing expression and higher processing effi ciency than in the spatial domain;however,they are unstable at low latitude.In this paper,the conclusion that the sum is 0 of two vertical magnetic fi eld components(magnetization inclinations are also perpendicular)in 2D is used for the 3D transformation of the magnetization direction and the magnetic field component.In addition,the transformation method at low latitudes based on vertical relationship(VMT)is proposed,which is an iterative algorithm that converts the transformation of the magnetization direction and the magnetic field component at the low latitude into the high latitude.This method restrains the instability of transformation of constant and variable magnetization direction and magnetic fi eld components in low latitudes.The accuracy,stability,and practicality are verifi ed from synthetic models and real data.
基金Supported by the Research Fund of Education Department under Grant No. 2009A305Science and Technology Department under Grant No. 20061023 in Liaoning Province of China+2 种基金National Natural Science Foundation of China under Grant No. 10874062National 211 Development Fund for Key Engineering Program of Liaoning UniversityYouth Foundation of Liaoning University under Grant No. 2007LDQN03
文摘The longitudinal-random-fieM mixed Ising model consisting of arbitrary spin values has been studied by the use of an effective field theory with correlations (EFT). The phase diagrams of systems with mixed spins: σ = 1/2, S = 1; σ = 1/2, S = 3/2 are plotted. Not only the discontinuity at T = 0 K, is found when both longitudinal fields are trimodal distributed, but also the trieritical behavior is observed in these phase diagrams between the bimodal and trimodal distributions of longitudinal fields, which is different from the single-spin one. The appearance of tricritical point is independent of the coordination number and spin values.
文摘In this letter, we have studied the influence of the external magnetic fields on tunneling of the spin-1 Bose condensate. We find that the population transfer between spin-0 and spin-±1 exhibits the step structure under the external cosinusoidal magnetic field and a combination of static and cosinusoidal one, respectively. Compared with the longitudinal component of the external magnetic field, the smaller the transverse component of the magnetic field is, the larger the time scale of exhibiting the step structure does. The tunneling current may exhibit periodically oscillation behavior when the ratio of the transverse component of the magnetic field is smaller than that of the longitudinal component, otherwise it exhibits a damply oscillating behavior. This means that the dynamical spin localization can be adjusted by the external magnetic fields.