Based on the improved interaction mechanism of two-layer model, this paper proposed Pixel Component Arranging and Comparing Algorithm (PCACA) and theoretically positioning algorithm, estimated the true temperature of ...Based on the improved interaction mechanism of two-layer model, this paper proposed Pixel Component Arranging and Comparing Algorithm (PCACA) and theoretically positioning algorithm, estimated the true temperature of mixed pixel in four extreme points in combination with the measurements of dry and wet points in calibration fields and improved the reliability of positioning dry and wet line. A new two-layer energy-separation algorithm was proposed,which was simple and direct without resistance network parameters for each pixel. We also proposed a new thought about the effect of advection. The albedo of mixed pixel was also separated with PCACA. In combination with two-layer energy-separation algorithm, the net radiation of mixed pixel was separated to overcome the uncertainty of conventional energy-separation algorithm using Beer's Law. Through the validation of retrieval result, this method is proved to be feasible and operational. At the same time, the uncertainty of this algorithm was objectively analyzed.展开更多
This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods,the adopted two-layer network structure in...This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods,the adopted two-layer network structure in this paper is generally directed, which is suitable for practical space missions. Firstly, distributed finite-time sliding-mode estimators and formation controllers in both layers are designed separately to improve the flexibility of the formation control system. By introducing the properties of affine transformation into formation control protocol design,the controllers can be used to track different time-varying target formation patterns. Besides, multilayer time-varying encirclements can be achieved with particular shapes to surround the moving target. In the sequel, by integrating adaptive neural networks and specialized artificial potential functions into backstepping controllers, the problems of uncertain Euler-Lagrange models, collision avoidance as well as formation reconfiguration are solved simultaneously. The stability of the proposed controllers is verified by the Lyapunov direct method. Finally, two simulation examples of triangle formation and more complex hexagon formation are presented to illustrate the feasibility of the theoretical results.展开更多
The optimal configuration of battery energy storage system is key to the designing of a microgrid.In this paper,a optimal configuration method of energy storage in grid-connected microgrid is proposed.Firstly,the two-...The optimal configuration of battery energy storage system is key to the designing of a microgrid.In this paper,a optimal configuration method of energy storage in grid-connected microgrid is proposed.Firstly,the two-layer decision model to allocate the capacity of storage is established.The decision variables in outer programming model are the capacity and power of the storage system.The objective is the least investment on the battery energy storage system.The decision variable in inner programming model is the charging and discharging power of battery.The objective is the lowest power fluctuation on the connection line.Then a case containing a grid-connected microgrid with wind power,photovoltaic,battery energy storage and load is studied,and the multi-scenario probabilistic method is used.The last result of energy storage configuration is calculated through the probability of each scene.展开更多
The power system restoration control has a higher uncertainty level than the preventive control of cascading failures. In order to ensure the feasibility of the decision support system of restoration control, a decisi...The power system restoration control has a higher uncertainty level than the preventive control of cascading failures. In order to ensure the feasibility of the decision support system of restoration control, a decision support framework for adaptive restoration control of transmission system is proposed, which can support the coordinated restoration of multiple partitions, coordinated restoration of units and loads, and coordination of multi-partition decision-making process and actual restoration process. The proposed framework is divided into two layers, global coordination layer and partition optimization layer. The upper layer partitions the transmission system according to the power outage scenario, constantly and dynamically adjusts the partitions during the restoration process, and optimizes the time-space decision-making of inter-partition connectivity. For each partition, the lower layer pre-selects restoration targets according to the estimated restoration income, optimizes the corresponding restoration paths, and evaluates the restoration plans according to the expected net income per unit of power consumption. During the restoration process, if the restoration operation such as energizing the outage branch fails, the current restoration plan will be adaptively switched to the sub-optimal one or re-optimized if necessary. The framework includes two operation modes, i.e., the on-line operation mode and training simulation mode, and provides an information interaction interface for collaborative restoration with related distribution systems. The effectiveness and adaptability of the proposed framework is demonstrated by simulations using the modified IEEE 118-bus system.展开更多
A weak nonlinear model of a two-layer barotropic ocean with Rayleigh dissipation is built.The analytic asymptotic solution is derived in the mid-latitude stationary wind field,and the physical meaning of the correspon...A weak nonlinear model of a two-layer barotropic ocean with Rayleigh dissipation is built.The analytic asymptotic solution is derived in the mid-latitude stationary wind field,and the physical meaning of the corresponding problem is discussed.展开更多
An integrated energy system(IES)planning method with modular simulation and optimization models is proposed in this paper.A two-layer bus structure is adopted in the simulation model,where the external bus structure i...An integrated energy system(IES)planning method with modular simulation and optimization models is proposed in this paper.A two-layer bus structure is adopted in the simulation model,where the external bus structure is used for power balance while the internal bus structure simulates the fast dynamics of electricity and slow dynamics of heat network in detail.In addition,an improved self-adaptive genetic algorithm(GA)is adopted in the optimization model to solve the multi-dimension and multi-time-scales optimization problem for the regional-user level IEPS.The proposed method can improve the extension flexibility of the system optimal planning model with expected accuracy.A case study is used to verify the effectiveness of the proposed planning method.展开更多
An analytical method was proposed to analyze the radiation and diffraction of water waves by a bottom-mounted circular cylinder in a two-layer fluid. Analytical expressions for added mass and damping coefficients, as ...An analytical method was proposed to analyze the radiation and diffraction of water waves by a bottom-mounted circular cylinder in a two-layer fluid. Analytical expressions for added mass and damping coefficients, as well as the wave excitation forces of the circular cylinder were obtained by an eigenfunction expansion method. The hydrodynamic forces on the bottom-mounted circular cylinder in a two-layer fluid include not only the added mass and damping coefficients, but also the wave forces of the surface and internal-wave modes. This is different from the case of a homogenous fluid. Some examples were given, showing that density stratification can have a relative large effect on these hydrodynamic forces over a wide range of frequencies.展开更多
In this study, we first sought to elucidate foam rheology to describe foam flow behavior, and then to experimentally investigate the pressure losses for both foam and foam-cuttings flow in a horizontal pipe by conside...In this study, we first sought to elucidate foam rheology to describe foam flow behavior, and then to experimentally investigate the pressure losses for both foam and foam-cuttings flow in a horizontal pipe by considering both varied foam qualities of 80%, 85% and 90% and foam velocities. Also, a two-layer numerical model to predict pressure loss was developed based on experimental observations of cuttings behavior. Results show that the foam behaves like a power-law fluid. Furthermore, and the pressure loss significantly increases as foam velocity increases, while the delivered cuttings concentration dramatically decreases. Moreover, results indicate that both the pressure loss and the delivered cuttings concentration increase with foam quality. Comparisons between the experimental results and numerical model predictions show satisfactory agreement.展开更多
The steady laminar two-dimensional thermocapillary convection of two superposed horizontal liquid layers in a shallow annular cavity was investigated using asymptotical analysis.The liquids were supposed to be immisci...The steady laminar two-dimensional thermocapillary convection of two superposed horizontal liquid layers in a shallow annular cavity was investigated using asymptotical analysis.The liquids were supposed to be immiscible with a nondeformable interface.The cavity was heated from the outer cylindrical wall and cooled at the inner wall.Bottom and top surfaces were rigid and adiabatic.Asymptotic solutions were obtained in the core region in the limit as the aspect ratio,which was defined as the ratio of the lower layer thickness to the gap width,and trended to zero.The numerical experiments were also carried out to compare with the asymptotic solution of the steady two-dimensional thermocapillary convection.It is found that the expressions of velocity and temperature fields in the core region are valid in the limit of the small aspect ratio.展开更多
On the basis of maps of sea level anomalies data set from October 1992 to January 2004, pronounced low frequency variations with periods of about 500 d are detected in the area near 20°N from 160°W to 130...On the basis of maps of sea level anomalies data set from October 1992 to January 2004, pronounced low frequency variations with periods of about 500 d are detected in the area near 20°N from 160°W to 130°E. A linear two-layer model is employed to explain the mechanism. It is found that the first-mode long baroclinic Rossby waves at 20°N in the northwest Pacific propagate westward in the form of free waves at a speed of about 10.3 cm/s. This confirms that the observed low frequency variabilities appear as baroclinic Rossby waves. It further shows that these low frequency variabilities around 20°N in the northwest Pacific can potentially be predicted with a lead up to 900 d.展开更多
At present,studies on large-amplitude internal solitary waves mostly adopt strong stratification models,such as the twoand three-layer Miyata–Choi–Camassa(MCC)internal wave models,which omit the pycnocline or treat ...At present,studies on large-amplitude internal solitary waves mostly adopt strong stratification models,such as the twoand three-layer Miyata–Choi–Camassa(MCC)internal wave models,which omit the pycnocline or treat it as another fluid layer with a constant density.Because the pycnocline exists in real oceans and cannot be omitted sometimes,the computational error of a large-amplitude internal solitary wave within the pycnocline introduced by the strong stratification approximation is unclear.In this study,the two-and three-layer MCC internal wave models are used to calculate the wave profile and wave speed of large-amplitude internal solitary waves.By comparing these results with the results provided by the Dubreil–Jacotin–Long(DJL)equation,which accurately describes large-amplitude internal solitary waves in a continuous density stratification,the computational errors of large-amplitude internal solitary waves at different pycnocline depths introduced by the strong stratification approximation are assessed.Although the pycnocline thicknesses are relatively large(accounting for 8%–10%of the total water depth),the error is much smaller under the three-layer approximation than under the two-layer approximation.展开更多
Tanlu fault zone(TLFZ)is the largest active fault zone in eastern China.It is characterized by complex tectonic evolution and multiple faults and marks the boundary between the North and South China blocks.An indepth ...Tanlu fault zone(TLFZ)is the largest active fault zone in eastern China.It is characterized by complex tectonic evolution and multiple faults and marks the boundary between the North and South China blocks.An indepth understanding of the distinct crustal structures of both parts of the TLFZ will provide valuable insights into the lithospheric and crustal thinning in eastern China,extensive magmatism since the Mesozoic,and formation mechanisms of metallogenic belts along the Yangtze River.In this study,a two-layer H-κstacking approach was adopted to estimate the thicknesses of the sediment and crystalline crust as well as the corresponding vP/vS ratios based on high-quality teleseismic P-wave receiver functions recorded by permanent and temporary stations in and around the TLFZ.The geological units in the study region were delineated,especially the crustal structures beneath extensive sedimentary basins on both sides of the TLFZ.The following conclusions can be drawn:(1)The crustal thickness in and around the TLFZ greatly varies depending on the segment.In the northern segment,the crust is relatively thin beneath the eastern part of the Songliao Basin,a broad uplift of the Moho can be observed,and the Moho descends from south to north.The crust below the central and southern segments becomes thinner from west to east.The thickness of the crust is less than 30 km toward the eastern side of the boundary between the Jiangsu and Anhui provinces,that is,significantly thinner than in other areas.In terms of the vP/vS ratios,high anomalies were detected in the central-southern segments of the TLFZ,indicating the upwelling of deep mantle magma via deep faults.(2)Positive isostatic gravity anomalies were observed in the eastern part of the northern segment of the TLFZ and in the eastern part of the Suwan segment.The crustal thickness is smaller than that obtained from the Airy model of isostasy.This suggests that the lower crust in this area may have experienced intensive transformation processes,which may be related to c展开更多
Thermal property is one of the most important properties of light-emitting diode （LED）. Thermal property of LED packaging material determines the heat dissipations of the phosphor and the chip surface, accordingly h...Thermal property is one of the most important properties of light-emitting diode （LED）. Thermal property of LED packaging material determines the heat dissipations of the phosphor and the chip surface, accordingly having an influence on the light-emitting efficiency and the life-span of the device. In this paper, photoacoustic piezoelectric （PAPE） technique has been employed to investigate the thermal properties of polyvinyl alcohol （]？VA） and silicon dioxide, which are the new and the traditional packaging materials in white LED, respectively. Firstly, the theory of PAPE technique has been developed for two-layer model in order to investigate soft materials; secondly, the experimental system has been set up and adjusted by measuring the reference sample; thirdly, the thermal diffusivities of PVA and silicon dioxide are measured and analysed. The experimental results show that PVA has a higher thermal diffusivity than silicon dioxide and is a better packaging material in the sense of thermal diffusivity for white LED.展开更多
A theoretic solution of one-dimensional heat transfer equation and a numerical simula-tion of 3D baroclinic circulation by MOM2 are investigated to understand the roles of bottom boundary mixing and the Topographic He...A theoretic solution of one-dimensional heat transfer equation and a numerical simula-tion of 3D baroclinic circulation by MOM2 are investigated to understand the roles of bottom boundary mixing and the Topographic Heat Accumulation Effect (THAE) in the Yellow Sea Cold Water Mass (YSCWM) circulation. Our results show: (i) The time scale of heat transfer changes from days to weeks and from shallow to deep water column. Strong bottom boundary mixing makes the thermocline domed. (ii) The circulation of YSCWM has a two-layer structure. The upper layer is cyclonic, while the lower layer is anticyclonic, and the lower layer is thinner (about 10—20 m) and weaker than the upper layer. The depth-integrated (net) circulation is cyclonic. (iii) The strength of the bottom boundary mixing influences the temperature structures greatly but has less effect on the velocity structure.展开更多
In order to improve accuracy of soil moisture inversion using remote sensing, a new thermal inertia model is proposed in this paper. The improved model needs only surface maximum temperature as the temperature paramet...In order to improve accuracy of soil moisture inversion using remote sensing, a new thermal inertia model is proposed in this paper. The improved model needs only surface maximum temperature as the temperature parameter input instead of input of the surface temperature difference, as well as the surface sensible and latent fluxes are introduced into boundary conditions of thermal conductivity equation. Furthermore, surface soil conductive heat transfer equation of two-layer model is used to solve the soil thermal inertia so that the remote sensing thermal inertia method can be ap- plied to regions with better-covered vegetation, but usually only for the bare areas or worse vegetation covered areas. The model has been tested at several locations in the area of west Inner Mongolia. Comparing the simulation of the new model with the measurements obtained by apparent thermal inertia and by field test, the result shows that the inertia thermal model can be used to estimate soil moisture in more reasonable accuracy.展开更多
文摘Based on the improved interaction mechanism of two-layer model, this paper proposed Pixel Component Arranging and Comparing Algorithm (PCACA) and theoretically positioning algorithm, estimated the true temperature of mixed pixel in four extreme points in combination with the measurements of dry and wet points in calibration fields and improved the reliability of positioning dry and wet line. A new two-layer energy-separation algorithm was proposed,which was simple and direct without resistance network parameters for each pixel. We also proposed a new thought about the effect of advection. The albedo of mixed pixel was also separated with PCACA. In combination with two-layer energy-separation algorithm, the net radiation of mixed pixel was separated to overcome the uncertainty of conventional energy-separation algorithm using Beer's Law. Through the validation of retrieval result, this method is proved to be feasible and operational. At the same time, the uncertainty of this algorithm was objectively analyzed.
基金sponsored by National Natural Science Foundation of China (Nos. 61673327, 51606161, 11602209, 91441128)Natural Science Foundation of Fujian Province of China (No. 2016J06011)China Scholarship Council (No. 201606310153)
文摘This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods,the adopted two-layer network structure in this paper is generally directed, which is suitable for practical space missions. Firstly, distributed finite-time sliding-mode estimators and formation controllers in both layers are designed separately to improve the flexibility of the formation control system. By introducing the properties of affine transformation into formation control protocol design,the controllers can be used to track different time-varying target formation patterns. Besides, multilayer time-varying encirclements can be achieved with particular shapes to surround the moving target. In the sequel, by integrating adaptive neural networks and specialized artificial potential functions into backstepping controllers, the problems of uncertain Euler-Lagrange models, collision avoidance as well as formation reconfiguration are solved simultaneously. The stability of the proposed controllers is verified by the Lyapunov direct method. Finally, two simulation examples of triangle formation and more complex hexagon formation are presented to illustrate the feasibility of the theoretical results.
基金The National Key Research and Development Plan(2017YFB0903504)Science and Technology Project of the SGCC(5210EF17001c).
文摘The optimal configuration of battery energy storage system is key to the designing of a microgrid.In this paper,a optimal configuration method of energy storage in grid-connected microgrid is proposed.Firstly,the two-layer decision model to allocate the capacity of storage is established.The decision variables in outer programming model are the capacity and power of the storage system.The objective is the least investment on the battery energy storage system.The decision variable in inner programming model is the charging and discharging power of battery.The objective is the lowest power fluctuation on the connection line.Then a case containing a grid-connected microgrid with wind power,photovoltaic,battery energy storage and load is studied,and the multi-scenario probabilistic method is used.The last result of energy storage configuration is calculated through the probability of each scene.
基金This work was supported in part by the China State Grid Corporation project of the Key Technologies of Power Grid Proactive Support for Energy Transition (No. 5100-202040325A-0-0-00).
文摘The power system restoration control has a higher uncertainty level than the preventive control of cascading failures. In order to ensure the feasibility of the decision support system of restoration control, a decision support framework for adaptive restoration control of transmission system is proposed, which can support the coordinated restoration of multiple partitions, coordinated restoration of units and loads, and coordination of multi-partition decision-making process and actual restoration process. The proposed framework is divided into two layers, global coordination layer and partition optimization layer. The upper layer partitions the transmission system according to the power outage scenario, constantly and dynamically adjusts the partitions during the restoration process, and optimizes the time-space decision-making of inter-partition connectivity. For each partition, the lower layer pre-selects restoration targets according to the estimated restoration income, optimizes the corresponding restoration paths, and evaluates the restoration plans according to the expected net income per unit of power consumption. During the restoration process, if the restoration operation such as energizing the outage branch fails, the current restoration plan will be adaptively switched to the sub-optimal one or re-optimized if necessary. The framework includes two operation modes, i.e., the on-line operation mode and training simulation mode, and provides an information interaction interface for collaborative restoration with related distribution systems. The effectiveness and adaptability of the proposed framework is demonstrated by simulations using the modified IEEE 118-bus system.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB403501)the National Natural Science Foundation of China (GrantNos. 41175058,41275062,and 11202106)
文摘A weak nonlinear model of a two-layer barotropic ocean with Rayleigh dissipation is built.The analytic asymptotic solution is derived in the mid-latitude stationary wind field,and the physical meaning of the corresponding problem is discussed.
基金This work was supported in part by the National Key Research and Development Program of China(2016YFB0900100)in part by the research on the key technologies of optimal configuration,operation and control for distributed energy storage in the background of the energy Internet by the State Grid Corporation of China.
文摘An integrated energy system(IES)planning method with modular simulation and optimization models is proposed in this paper.A two-layer bus structure is adopted in the simulation model,where the external bus structure is used for power balance while the internal bus structure simulates the fast dynamics of electricity and slow dynamics of heat network in detail.In addition,an improved self-adaptive genetic algorithm(GA)is adopted in the optimization model to solve the multi-dimension and multi-time-scales optimization problem for the regional-user level IEPS.The proposed method can improve the extension flexibility of the system optimal planning model with expected accuracy.A case study is used to verify the effectiveness of the proposed planning method.
基金Project supported by the Foundation of the Excellent State Key Laboratory (Grant No. 50323004) the KSJ Foundation of the Education Ministry of China.
文摘An analytical method was proposed to analyze the radiation and diffraction of water waves by a bottom-mounted circular cylinder in a two-layer fluid. Analytical expressions for added mass and damping coefficients, as well as the wave excitation forces of the circular cylinder were obtained by an eigenfunction expansion method. The hydrodynamic forces on the bottom-mounted circular cylinder in a two-layer fluid include not only the added mass and damping coefficients, but also the wave forces of the surface and internal-wave modes. This is different from the case of a homogenous fluid. Some examples were given, showing that density stratification can have a relative large effect on these hydrodynamic forces over a wide range of frequencies.
基金Japan Oil,Gas and Metals National Corporation(JOGMEC) for their partial financial support of this research
文摘In this study, we first sought to elucidate foam rheology to describe foam flow behavior, and then to experimentally investigate the pressure losses for both foam and foam-cuttings flow in a horizontal pipe by considering both varied foam qualities of 80%, 85% and 90% and foam velocities. Also, a two-layer numerical model to predict pressure loss was developed based on experimental observations of cuttings behavior. Results show that the foam behaves like a power-law fluid. Furthermore, and the pressure loss significantly increases as foam velocity increases, while the delivered cuttings concentration dramatically decreases. Moreover, results indicate that both the pressure loss and the delivered cuttings concentration increase with foam quality. Comparisons between the experimental results and numerical model predictions show satisfactory agreement.
基金supported by the National Natural Science Foundation of China (Grant No.50776102)
文摘The steady laminar two-dimensional thermocapillary convection of two superposed horizontal liquid layers in a shallow annular cavity was investigated using asymptotical analysis.The liquids were supposed to be immiscible with a nondeformable interface.The cavity was heated from the outer cylindrical wall and cooled at the inner wall.Bottom and top surfaces were rigid and adiabatic.Asymptotic solutions were obtained in the core region in the limit as the aspect ratio,which was defined as the ratio of the lower layer thickness to the gap width,and trended to zero.The numerical experiments were also carried out to compare with the asymptotic solution of the steady two-dimensional thermocapillary convection.It is found that the expressions of velocity and temperature fields in the core region are valid in the limit of the small aspect ratio.
基金This study was supported by the National Natural Science Foundation of China under contract Nos 40136010 and 40520140074.
文摘On the basis of maps of sea level anomalies data set from October 1992 to January 2004, pronounced low frequency variations with periods of about 500 d are detected in the area near 20°N from 160°W to 130°E. A linear two-layer model is employed to explain the mechanism. It is found that the first-mode long baroclinic Rossby waves at 20°N in the northwest Pacific propagate westward in the form of free waves at a speed of about 10.3 cm/s. This confirms that the observed low frequency variabilities appear as baroclinic Rossby waves. It further shows that these low frequency variabilities around 20°N in the northwest Pacific can potentially be predicted with a lead up to 900 d.
基金the Fundamental Research Funds for the Central Universities (No. 3072022FSC0101)the National Natural Science Foundation of China (Nos. 12202114, 52261135547)+4 种基金the China Postdoctoral Science Foundation (No. 2022M710932)the State Key Laboratory of Coastal and Offshore EngineeringDalian University of Technology (No. LP2202)the Qingdao Postdoctoral Application Projectthe Heilongjiang Touyan Innovation Team Program
文摘At present,studies on large-amplitude internal solitary waves mostly adopt strong stratification models,such as the twoand three-layer Miyata–Choi–Camassa(MCC)internal wave models,which omit the pycnocline or treat it as another fluid layer with a constant density.Because the pycnocline exists in real oceans and cannot be omitted sometimes,the computational error of a large-amplitude internal solitary wave within the pycnocline introduced by the strong stratification approximation is unclear.In this study,the two-and three-layer MCC internal wave models are used to calculate the wave profile and wave speed of large-amplitude internal solitary waves.By comparing these results with the results provided by the Dubreil–Jacotin–Long(DJL)equation,which accurately describes large-amplitude internal solitary waves in a continuous density stratification,the computational errors of large-amplitude internal solitary waves at different pycnocline depths introduced by the strong stratification approximation are assessed.Although the pycnocline thicknesses are relatively large(accounting for 8%–10%of the total water depth),the error is much smaller under the three-layer approximation than under the two-layer approximation.
文摘Tanlu fault zone(TLFZ)is the largest active fault zone in eastern China.It is characterized by complex tectonic evolution and multiple faults and marks the boundary between the North and South China blocks.An indepth understanding of the distinct crustal structures of both parts of the TLFZ will provide valuable insights into the lithospheric and crustal thinning in eastern China,extensive magmatism since the Mesozoic,and formation mechanisms of metallogenic belts along the Yangtze River.In this study,a two-layer H-κstacking approach was adopted to estimate the thicknesses of the sediment and crystalline crust as well as the corresponding vP/vS ratios based on high-quality teleseismic P-wave receiver functions recorded by permanent and temporary stations in and around the TLFZ.The geological units in the study region were delineated,especially the crustal structures beneath extensive sedimentary basins on both sides of the TLFZ.The following conclusions can be drawn:(1)The crustal thickness in and around the TLFZ greatly varies depending on the segment.In the northern segment,the crust is relatively thin beneath the eastern part of the Songliao Basin,a broad uplift of the Moho can be observed,and the Moho descends from south to north.The crust below the central and southern segments becomes thinner from west to east.The thickness of the crust is less than 30 km toward the eastern side of the boundary between the Jiangsu and Anhui provinces,that is,significantly thinner than in other areas.In terms of the vP/vS ratios,high anomalies were detected in the central-southern segments of the TLFZ,indicating the upwelling of deep mantle magma via deep faults.(2)Positive isostatic gravity anomalies were observed in the eastern part of the northern segment of the TLFZ and in the eastern part of the Suwan segment.The crustal thickness is smaller than that obtained from the Airy model of isostasy.This suggests that the lower crust in this area may have experienced intensive transformation processes,which may be related to c
基金Project supported by the National Nature Science Foundation of China (Grant No. 50506006)the National High Technology Research and Development Program of China (Grant No. 2006AA03A116)the Youth Foundation of University of Electronic Science and Technology of China (Grant No. JX05024)
文摘Thermal property is one of the most important properties of light-emitting diode （LED）. Thermal property of LED packaging material determines the heat dissipations of the phosphor and the chip surface, accordingly having an influence on the light-emitting efficiency and the life-span of the device. In this paper, photoacoustic piezoelectric （PAPE） technique has been employed to investigate the thermal properties of polyvinyl alcohol （]？VA） and silicon dioxide, which are the new and the traditional packaging materials in white LED, respectively. Firstly, the theory of PAPE technique has been developed for two-layer model in order to investigate soft materials; secondly, the experimental system has been set up and adjusted by measuring the reference sample; thirdly, the thermal diffusivities of PVA and silicon dioxide are measured and analysed. The experimental results show that PVA has a higher thermal diffusivity than silicon dioxide and is a better packaging material in the sense of thermal diffusivity for white LED.
基金the National Natural Science Foundation of China (Grant Nos. 49736200 and 49976001) the Key Basic Research and Development Plan (Grant Nos. 1999043802 and 1999043702)+1 种基金 and the Youth Marine Science Foundation of State Oceanic Administration China (Gr
文摘A theoretic solution of one-dimensional heat transfer equation and a numerical simula-tion of 3D baroclinic circulation by MOM2 are investigated to understand the roles of bottom boundary mixing and the Topographic Heat Accumulation Effect (THAE) in the Yellow Sea Cold Water Mass (YSCWM) circulation. Our results show: (i) The time scale of heat transfer changes from days to weeks and from shallow to deep water column. Strong bottom boundary mixing makes the thermocline domed. (ii) The circulation of YSCWM has a two-layer structure. The upper layer is cyclonic, while the lower layer is anticyclonic, and the lower layer is thinner (about 10—20 m) and weaker than the upper layer. The depth-integrated (net) circulation is cyclonic. (iii) The strength of the bottom boundary mixing influences the temperature structures greatly but has less effect on the velocity structure.
文摘In order to improve accuracy of soil moisture inversion using remote sensing, a new thermal inertia model is proposed in this paper. The improved model needs only surface maximum temperature as the temperature parameter input instead of input of the surface temperature difference, as well as the surface sensible and latent fluxes are introduced into boundary conditions of thermal conductivity equation. Furthermore, surface soil conductive heat transfer equation of two-layer model is used to solve the soil thermal inertia so that the remote sensing thermal inertia method can be ap- plied to regions with better-covered vegetation, but usually only for the bare areas or worse vegetation covered areas. The model has been tested at several locations in the area of west Inner Mongolia. Comparing the simulation of the new model with the measurements obtained by apparent thermal inertia and by field test, the result shows that the inertia thermal model can be used to estimate soil moisture in more reasonable accuracy.
