The results of a heat-conduction experiment with a central point source in a sand barrel shows that the temperature of the heat source increase much faster in sand saturated with oil and air （dry sand） than in water...The results of a heat-conduction experiment with a central point source in a sand barrel shows that the temperature of the heat source increase much faster in sand saturated with oil and air （dry sand） than in water sand. During cooling the temperature of the central heat source goes down slower in oil- or air-saturated sands than in water sands. Based on the theory of heat-conduction in porous media and the experimental results, we developed a new heat-conduction logging technique which utilizes an artificial heat source （dynamite charge or electric heater） to heat up target forma- tions in the borehole and then measure the change of temperature at a later time. Post-frac oil production is shown to be directly proportional to the size of the temperature anomaly when other reservoir parameters are fairly consistent. The method is used to evaluate potential oil production for marginal reservoirs in the FY formation in Song-Liao basin of China.展开更多
A high-order accuracy explicit difference scheme for solving 4-dimensional heatconduction equation is constructed. The stability condition is r = △t/△x^2 = △t/△y^2 = △t/△z^2 = △t/△w^2 〈 3/8, and the truncatio...A high-order accuracy explicit difference scheme for solving 4-dimensional heatconduction equation is constructed. The stability condition is r = △t/△x^2 = △t/△y^2 = △t/△z^2 = △t/△w^2 〈 3/8, and the truncation error is O（△t^2 ＋ △x^4）.展开更多
In this paper, a class of explicit difference schemes with parameters for solving five-dimensional heat-conduction equation are constructed and studied.the truncation error reaches O（τ^2＋ h%4）, and the stability c...In this paper, a class of explicit difference schemes with parameters for solving five-dimensional heat-conduction equation are constructed and studied.the truncation error reaches O（τ^2＋ h%4）, and the stability condition is given. Finally, the numerical examples and numerical results are presented to show the advantage of the schemes and the correctness of theoretical analysis.展开更多
The model of transient behavior of semiconductor with heat-conduction is an initial and boundary problem. Alternating-direction multistep preconditioned iterative methods and theory analyses are given in this paper. E...The model of transient behavior of semiconductor with heat-conduction is an initial and boundary problem. Alternating-direction multistep preconditioned iterative methods and theory analyses are given in this paper. Electric potential equation is approximated by mixed finite element method, concentration and heat-conduction equations are approximated by Galerkin alternating-direction multistep methods. Error estimates of optimal order in L2 are demonstrated.展开更多
In this paper the nonlinear heat-conduction equations rhoc partial derivativew/partial derivativet = partial derivative/partial derivativex (k partial derivativew/partial derivativex) with Dirichlet boundary condition...In this paper the nonlinear heat-conduction equations rhoc partial derivativew/partial derivativet = partial derivative/partial derivativex (k partial derivativew/partial derivativex) with Dirichlet boundary condition and the nonlinear boundary condition are studied. The asymptotic behavior of the global of solution are analyzed by using Lyapuunov function. As its application, the approximate solutions are constructed.展开更多
Reference [1] deals with the uniqueness of solution to problem （A） and solution of problem （A） is continuously dependent on free term and initial value under certain conditions. This paper discuss the solution of ...Reference [1] deals with the uniqueness of solution to problem （A） and solution of problem （A） is continuously dependent on free term and initial value under certain conditions. This paper discuss the solution of problem （A） is continuously dependent on boundary value on the basis of references [2] and [3].展开更多
In this paper,we consider an initial boundary value problem for the nonhomo-geneous heat-conducting magnetohydrodynamic fuids when the viscosityμ,magnetic dif-fusivity v and heat conductivity k depend on the temperat...In this paper,we consider an initial boundary value problem for the nonhomo-geneous heat-conducting magnetohydrodynamic fuids when the viscosityμ,magnetic dif-fusivity v and heat conductivity k depend on the temperature according to μ(0)=°,k(0)=08,v(0)=07,withα,>0,β≥0.We prove the global existence of a unique strong solution provided that ■ is suitably small.In addition,we also get some results of the large-time behavior and exponential decay estimates.展开更多
By measuring the effective thermal conductivity, taking photos of the distribution of the nano-particles in the fluids and photos that reflect the interfacial phenomena between nano-particles and fluids, we try to exp...By measuring the effective thermal conductivity, taking photos of the distribution of the nano-particles in the fluids and photos that reflect the interfacial phenomena between nano-particles and fluids, we try to explain the possible mechanism for heat conductive enhancement.展开更多
We study an initial boundary value problem for the Navier-Stokes equations of compressible viscous heat-conductive fluids in a 2-D periodic domain or the unit square domain. We establish a blow-up criterion for the lo...We study an initial boundary value problem for the Navier-Stokes equations of compressible viscous heat-conductive fluids in a 2-D periodic domain or the unit square domain. We establish a blow-up criterion for the local strong solutions in terms of the gradient of the velocity only, which coincides with the famous Beale-Kato-Majda criterion for ideal incompressible flows.展开更多
In this paper,we prove a blow-up criterion of strong solutions to the 3-D viscous and non-resistive magnetohydrodynamic equations for compressible heat-conducting flows with initial vacuum.This blow-up criterion depen...In this paper,we prove a blow-up criterion of strong solutions to the 3-D viscous and non-resistive magnetohydrodynamic equations for compressible heat-conducting flows with initial vacuum.This blow-up criterion depends only on the gradient of velocity and the temperature,which is similar to the one for compressible Navier-Stokes equations.展开更多
The Heishan geothermal area is positioned above the sole Yunnane-Tibet high-temperature geothermal belt,where huge geothermal energy resources are available.Utilizing the characteristics of large exploration depth,ext...The Heishan geothermal area is positioned above the sole Yunnane-Tibet high-temperature geothermal belt,where huge geothermal energy resources are available.Utilizing the characteristics of large exploration depth,extensive coverage,and high precision of the wide-field elec-tromagnetic method,four survey lines were deployed,totaling 29.8 km,to enable a comprehensive analysis of the granite structure and fault distribution.The results indicate that the rocks within the area can be vertically divided into a granite basement and a fractured layer.Moreover,three different zones of resistivity were identified:the granite basement zone has a resistivity range of 2500-20000 U m,whereas the compressional shear zone and the secondary fault zone have a resistivity range of 750-2500 U m,and the extensional fault zone and the main fault zone have resistivity values below 750 U m.The Heishan-Hejian fault and the fault zone formed during its right-lateral strike-slip process,as well as the controlled area of the Qianmaihe fault,are all favorable targets.Of these,the Qianmahe fault possesses a larger-scale heat-conducting and water-controlling structure.In addition,in the secondary fault-controlled area extending to the west,the zone between F2’and F4 exhibits renewed tectonic activity,suggesting a greater potential for geothermal resources.展开更多
In the development of static luminescent materials with remarkable optical-thermal performance and low cost, next-generation high-brightness laser lighting faces a key challenge. Herein, a unique composite architectur...In the development of static luminescent materials with remarkable optical-thermal performance and low cost, next-generation high-brightness laser lighting faces a key challenge. Herein, a unique composite architecture of Y3Al5O_(12):Ce^(3+) (YAG) phosphor-in-glass film coated on different heat-conducting substrates (PiGF@HCSs), i.e., PiGF@sapphire, PiGF@Al_(2)O_(3), PiGF@AlN, and PiGF@BN–AlN composites, was designed and prepared by a simple film printing and low-temperature sintering technology. The heat-conducting substrates significantly affect the luminescence saturation and phosphor conversion of PiGF@HCSs, allowing substrates with higher thermal conductivity (TC) to have a higher laser power density (LPD) and higher reflectivity to enable higher luminous efficacy (LE). As a consequence, PiGF@sapphire realizes a luminous flux (LF) of 2076 lm@12 W/mm^(2), which is higher than those of PiGF@Al_(2)O_(3) (1890 lm@15 W/mm^(2)) and PiGF@AlN (1915 lm@24 W/mm^(2)), whilePiGF@BN–AlN enables a maximum LF of 3058 lm@21 W/mm^(2). Furthermore, the LE of PiGF@BN–AlN reaches 194 lm/W, which is 1.6 times that of PiGF@AlN, while those of PiGF@sapphire and PiGF@Al_(2)O_(3) are 192 and 150 lm/W, respectively. The working temperature of PiGF@AlN is only 93.3℃ under LPD of 9 W/mm^(2), while those of PiGF@sapphire, PiGF@Al_(2)O_(3), and PiGF@BN–AlN increase to 193.8, 133.6, and 117℃, respectively. These findings provide guidance for commercial applications of PiGF@HCS converters in high-brightness laser lighting and displays.展开更多
Dependence of the thermal conductivity on the length of two armchair single-walled carbon nanotubes （SWNTs） is studied by the nonequilibrium molecular dynamics （MD） method with Brenner Ⅱ potential. The thermal co...Dependence of the thermal conductivity on the length of two armchair single-walled carbon nanotubes （SWNTs） is studied by the nonequilibrium molecular dynamics （MD） method with Brenner Ⅱ potential. The thermal conductivities are calculated for （5, 5） and （7, 7） SWNTs with lengths ranging from 22 to 155nm. The results show that the thermal conductivity of SWNTs is sensitive to the length and it does not converge to a finite value when the tube length increases up to 155nm, however it obeys a power law relation.展开更多
Using the scattering matrix method, we investigate the thermal transport m a nanostructure at low temperarures. It is found that phonon transport exhibits some novel and interesting features： resonant transmission, r...Using the scattering matrix method, we investigate the thermal transport m a nanostructure at low temperarures. It is found that phonon transport exhibits some novel and interesting features： resonant transmission, resonant reflection, and small thermal conductance. A comparison between thermal conductances is performed when stress-free and hard-wall boundary conditions are applied for acoustic modes, respectively. The result indicates that the characteristics of the thermal conductance versus temperature for different types of boundary conditions are qualitatively different.展开更多
Collocation method is put forward to solve the semiconductor problem with heat-conduction, whose mathematical model is described by an initial and boundary problem for a nonlinear partial differential equation system....Collocation method is put forward to solve the semiconductor problem with heat-conduction, whose mathematical model is described by an initial and boundary problem for a nonlinear partial differential equation system. One elliptic equation is for the electric potential, and three parabolic equations are for the electron concentration, hole concentration and heat-conduction. Using the prior estimate and technique of differential equations, we obtained almost optimal error estimates in L2.展开更多
By using Differential Scanning Caborimetry（DSC）,Thermogravimetric（TG） thermal analysis etc,we determined thermal physical properties,such as the heat conduction performance, specific heat capacity,heat stability a...By using Differential Scanning Caborimetry（DSC）,Thermogravimetric（TG） thermal analysis etc,we determined thermal physical properties,such as the heat conduction performance, specific heat capacity,heat stability and etc,of different metal oxide/Nylon 1010 composites.The results show that after added ZnO,CuO,Fe3O4 in PAlOlO matrix,the thermal conductivity of composites linear increases with the increasing of the quality score of metal oxide.When using ZnO as thermal conductive filler and the particle diameter ranges 35 to 40μm,heat conduction performance of the modified composites is the best.The thermal conductivity of ZnO/PA1010 composites linear increases with the temperature increasing.The heat capacity of Nylon 1010 and all kinds of metal oxide/Nylon 1010 increases gradually with the temperature rising.In the same temperature,heat capacity of the modified composites reduces gradually with the content of metal oxide increasing.The glass transition temperature of Nylon 1010 is about 47℃or so,and adding metal oxide can improve the thermal stability of composites.展开更多
The calculation of the temperature field of an underwater concrete tank system storing crude oil is relatively complex. Based on experimental data and optimization analysis of relative parameters, unsteady heat-transf...The calculation of the temperature field of an underwater concrete tank system storing crude oil is relatively complex. Based on experimental data and optimization analysis of relative parameters, unsteady heat-transfer is calculated by use of heat equilibrium theory. It is found that the predicted value of temperature is in good agreement with experimental data.展开更多
文摘The results of a heat-conduction experiment with a central point source in a sand barrel shows that the temperature of the heat source increase much faster in sand saturated with oil and air （dry sand） than in water sand. During cooling the temperature of the central heat source goes down slower in oil- or air-saturated sands than in water sands. Based on the theory of heat-conduction in porous media and the experimental results, we developed a new heat-conduction logging technique which utilizes an artificial heat source （dynamite charge or electric heater） to heat up target forma- tions in the borehole and then measure the change of temperature at a later time. Post-frac oil production is shown to be directly proportional to the size of the temperature anomaly when other reservoir parameters are fairly consistent. The method is used to evaluate potential oil production for marginal reservoirs in the FY formation in Song-Liao basin of China.
基金NSF of the Education Department of Henan Province(20031100010)
文摘A high-order accuracy explicit difference scheme for solving 4-dimensional heatconduction equation is constructed. The stability condition is r = △t/△x^2 = △t/△y^2 = △t/△z^2 = △t/△w^2 〈 3/8, and the truncation error is O（△t^2 ＋ △x^4）.
基金Supported by NSF of the Education Department of Henan Province(20031100010)
文摘In this paper, a class of explicit difference schemes with parameters for solving five-dimensional heat-conduction equation are constructed and studied.the truncation error reaches O（τ^2＋ h%4）, and the stability condition is given. Finally, the numerical examples and numerical results are presented to show the advantage of the schemes and the correctness of theoretical analysis.
基金This research was surpported by the National Natural Science Foundation , Mathematical TY Foun-dation (TY10126029) of China and the Youth Foundation of Shandong University.
文摘The model of transient behavior of semiconductor with heat-conduction is an initial and boundary problem. Alternating-direction multistep preconditioned iterative methods and theory analyses are given in this paper. Electric potential equation is approximated by mixed finite element method, concentration and heat-conduction equations are approximated by Galerkin alternating-direction multistep methods. Error estimates of optimal order in L2 are demonstrated.
文摘In this paper the nonlinear heat-conduction equations rhoc partial derivativew/partial derivativet = partial derivative/partial derivativex (k partial derivativew/partial derivativex) with Dirichlet boundary condition and the nonlinear boundary condition are studied. The asymptotic behavior of the global of solution are analyzed by using Lyapuunov function. As its application, the approximate solutions are constructed.
文摘Reference [1] deals with the uniqueness of solution to problem （A） and solution of problem （A） is continuously dependent on free term and initial value under certain conditions. This paper discuss the solution of problem （A） is continuously dependent on boundary value on the basis of references [2] and [3].
基金supported by the National Natural Science Foundation of China(No.11931013)the Natural Science Foundation of Guangxi Province(No.2022GXNSFDA035078)the Foundamental Research Funds for the Central Universities,CHD(No.300102122115).
文摘In this paper,we consider an initial boundary value problem for the nonhomo-geneous heat-conducting magnetohydrodynamic fuids when the viscosityμ,magnetic dif-fusivity v and heat conductivity k depend on the temperature according to μ(0)=°,k(0)=08,v(0)=07,withα,>0,β≥0.We prove the global existence of a unique strong solution provided that ■ is suitably small.In addition,we also get some results of the large-time behavior and exponential decay estimates.
基金The project is financially supported by the National Nature Science Foundation of China with Grant number(No.59995550-3)Thanks also for the valuable suggestions from Prof Yuqin Gu of the Department of Engineering Mechanics, Tsinghua University and Pr
文摘By measuring the effective thermal conductivity, taking photos of the distribution of the nano-particles in the fluids and photos that reflect the interfacial phenomena between nano-particles and fluids, we try to explain the possible mechanism for heat conductive enhancement.
基金supported by the China Postdoctoral Science Foundation (20090450333)supported by the National Basic Research Program (2005CB321700)NSFC (40890154)
文摘We study an initial boundary value problem for the Navier-Stokes equations of compressible viscous heat-conductive fluids in a 2-D periodic domain or the unit square domain. We establish a blow-up criterion for the local strong solutions in terms of the gradient of the velocity only, which coincides with the famous Beale-Kato-Majda criterion for ideal incompressible flows.
基金supported by NSFC (11171228,10801111,10971171)the fundamental Research Funds for the Central University (2010121006)the Natural Science Foundation of Fujian Province of China (2010J05011)
文摘In this paper,we prove a blow-up criterion of strong solutions to the 3-D viscous and non-resistive magnetohydrodynamic equations for compressible heat-conducting flows with initial vacuum.This blow-up criterion depends only on the gradient of velocity and the temperature,which is similar to the one for compressible Navier-Stokes equations.
基金supported by research funds of the Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control(2201K004)the Key Research and Development Program in Yunnan Province,“Research on Key Technologies for Exploration and Development of Deep and Medium Geothermal Energy in Yunnan Province”(No.202302AF080001)+2 种基金“Mineralization laws and Prospecting Technology Research in the Key Mining Cluster Area of Western Yunnan Province”(No.202303AA080006)the Shenzhen Municipal Science and Technology Innovation Committee(JCYJ20220818103010021)the Guangdong Provincial Marine Economy Special Project,GDNRC[2021]57.
文摘The Heishan geothermal area is positioned above the sole Yunnane-Tibet high-temperature geothermal belt,where huge geothermal energy resources are available.Utilizing the characteristics of large exploration depth,extensive coverage,and high precision of the wide-field elec-tromagnetic method,four survey lines were deployed,totaling 29.8 km,to enable a comprehensive analysis of the granite structure and fault distribution.The results indicate that the rocks within the area can be vertically divided into a granite basement and a fractured layer.Moreover,three different zones of resistivity were identified:the granite basement zone has a resistivity range of 2500-20000 U m,whereas the compressional shear zone and the secondary fault zone have a resistivity range of 750-2500 U m,and the extensional fault zone and the main fault zone have resistivity values below 750 U m.The Heishan-Hejian fault and the fault zone formed during its right-lateral strike-slip process,as well as the controlled area of the Qianmaihe fault,are all favorable targets.Of these,the Qianmahe fault possesses a larger-scale heat-conducting and water-controlling structure.In addition,in the secondary fault-controlled area extending to the west,the zone between F2’and F4 exhibits renewed tectonic activity,suggesting a greater potential for geothermal resources.
基金supported by the National Natural Science Foundation of China(No.52475594)the National Key R&D Program of China(No.2022YFB3604803).
文摘In the development of static luminescent materials with remarkable optical-thermal performance and low cost, next-generation high-brightness laser lighting faces a key challenge. Herein, a unique composite architecture of Y3Al5O_(12):Ce^(3+) (YAG) phosphor-in-glass film coated on different heat-conducting substrates (PiGF@HCSs), i.e., PiGF@sapphire, PiGF@Al_(2)O_(3), PiGF@AlN, and PiGF@BN–AlN composites, was designed and prepared by a simple film printing and low-temperature sintering technology. The heat-conducting substrates significantly affect the luminescence saturation and phosphor conversion of PiGF@HCSs, allowing substrates with higher thermal conductivity (TC) to have a higher laser power density (LPD) and higher reflectivity to enable higher luminous efficacy (LE). As a consequence, PiGF@sapphire realizes a luminous flux (LF) of 2076 lm@12 W/mm^(2), which is higher than those of PiGF@Al_(2)O_(3) (1890 lm@15 W/mm^(2)) and PiGF@AlN (1915 lm@24 W/mm^(2)), whilePiGF@BN–AlN enables a maximum LF of 3058 lm@21 W/mm^(2). Furthermore, the LE of PiGF@BN–AlN reaches 194 lm/W, which is 1.6 times that of PiGF@AlN, while those of PiGF@sapphire and PiGF@Al_(2)O_(3) are 192 and 150 lm/W, respectively. The working temperature of PiGF@AlN is only 93.3℃ under LPD of 9 W/mm^(2), while those of PiGF@sapphire, PiGF@Al_(2)O_(3), and PiGF@BN–AlN increase to 193.8, 133.6, and 117℃, respectively. These findings provide guidance for commercial applications of PiGF@HCS converters in high-brightness laser lighting and displays.
文摘Dependence of the thermal conductivity on the length of two armchair single-walled carbon nanotubes （SWNTs） is studied by the nonequilibrium molecular dynamics （MD） method with Brenner Ⅱ potential. The thermal conductivities are calculated for （5, 5） and （7, 7） SWNTs with lengths ranging from 22 to 155nm. The results show that the thermal conductivity of SWNTs is sensitive to the length and it does not converge to a finite value when the tube length increases up to 155nm, however it obeys a power law relation.
基金Supported by the National Natural Science Foundation of China under Grant No 10547132, and the Young Teacher Foundation of Tianjin University under Grant No 5110117.
文摘Using the scattering matrix method, we investigate the thermal transport m a nanostructure at low temperarures. It is found that phonon transport exhibits some novel and interesting features： resonant transmission, resonant reflection, and small thermal conductance. A comparison between thermal conductances is performed when stress-free and hard-wall boundary conditions are applied for acoustic modes, respectively. The result indicates that the characteristics of the thermal conductance versus temperature for different types of boundary conditions are qualitatively different.
基金The NNSF.MTYF(10126029)of China and the YF of Shandong University.
文摘Collocation method is put forward to solve the semiconductor problem with heat-conduction, whose mathematical model is described by an initial and boundary problem for a nonlinear partial differential equation system. One elliptic equation is for the electric potential, and three parabolic equations are for the electron concentration, hole concentration and heat-conduction. Using the prior estimate and technique of differential equations, we obtained almost optimal error estimates in L2.
基金Natural Science Foundation of Jiangsu Province,China(Grant No.SBK201121291)
文摘By using Differential Scanning Caborimetry（DSC）,Thermogravimetric（TG） thermal analysis etc,we determined thermal physical properties,such as the heat conduction performance, specific heat capacity,heat stability and etc,of different metal oxide/Nylon 1010 composites.The results show that after added ZnO,CuO,Fe3O4 in PAlOlO matrix,the thermal conductivity of composites linear increases with the increasing of the quality score of metal oxide.When using ZnO as thermal conductive filler and the particle diameter ranges 35 to 40μm,heat conduction performance of the modified composites is the best.The thermal conductivity of ZnO/PA1010 composites linear increases with the temperature increasing.The heat capacity of Nylon 1010 and all kinds of metal oxide/Nylon 1010 increases gradually with the temperature rising.In the same temperature,heat capacity of the modified composites reduces gradually with the content of metal oxide increasing.The glass transition temperature of Nylon 1010 is about 47℃or so,and adding metal oxide can improve the thermal stability of composites.
基金This project was financially supported by the National Natural Science Foundation of China(Grant No.59895410)
文摘The calculation of the temperature field of an underwater concrete tank system storing crude oil is relatively complex. Based on experimental data and optimization analysis of relative parameters, unsteady heat-transfer is calculated by use of heat equilibrium theory. It is found that the predicted value of temperature is in good agreement with experimental data.
