期刊文献+
共找到1,845篇文章
< 1 2 93 >
每页显示 20 50 100
NUMERICAL MODELING FOR COUPLED THERMO-HYDRO-MECHANICAL AND CHEMICAL PROCESSES (THMC) OF GEOLOGICAL MEDIA——INTERNATIONAL AND CHINESE EXPERIENCES 被引量:18
1
作者 Jing Lanru,Feng Xiating (Institute of Rock and Soil Mechanics,The Chinese Academy of Sciences, Wuhan 430071 China) 《岩石力学与工程学报》 EI CAS CSCD 北大核心 2003年第10期1704-1715,共12页
The coupled thermo-hydro-mechanical and chemical (THMC) processes of stress/deformation,fluid flow,temperature and geochemical reactions of the geological media,namely fractured rocks and soils,play an important role ... The coupled thermo-hydro-mechanical and chemical (THMC) processes of stress/deformation,fluid flow,temperature and geochemical reactions of the geological media,namely fractured rocks and soils,play an important role in design,construction,operation and environmental impact assessments of rock and soil engineering works such as underground nuclear waste repositories,oil/gas production and storage,geothermal energy extraction,landslides and slope stability,hydropower and water conservancy complexes,etc. This paper presents an overview of the international and Chinese experiences in numerical modeling of the coupled THMC processes for both the state-of-the-knowledge,remaining challenges and possible future prospects. 展开更多
关键词 地质力学 化学耦合反应 数值模拟 国外
下载PDF
Dynamic coupled thermo-hydro-mechanical problem for heterogeneous deep-sea sediments under vibration of mining vehicle
2
作者 Wei ZHU Xingkai MA +1 位作者 Xinyu SHI Wenbo MA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2023年第4期603-622,共20页
Due to the influence of deep-sea environment,deep-sea sediments are usually heterogeneous,and their moduli of elasticity and density change as depth changes.Combined with the characteristics of deep-sea sediments,the ... Due to the influence of deep-sea environment,deep-sea sediments are usually heterogeneous,and their moduli of elasticity and density change as depth changes.Combined with the characteristics of deep-sea sediments,the thermo-hydro-mechanical coupling dynamic response model of heterogeneous saturated porous sediments can be established to study the influence of elastic modulus,density,frequency,and load amplitude changes on the model.Based on the Green-Lindsay generalized thermoelasticity theory and Darcy’s law,the thermo-hydro-mechanical coupled dynamic response model and governing equations of heterogeneous deep-sea sediments with nonlinear elastic modulus and density are established.The analytical solutions of dimensionless vertical displacement,vertical stress,excess pore water pressure,and temperature are obtained by means of normal modal analysis,which are depicted graphically.The results show that the changes of elastic modulus and density have few effects on vertical displacement,vertical stress,and temperature,but have great effects on excess pore water pressure.When the mining machine vibrates,the heterogeneity of deep-sea sediments has great influence on vertical displacement,vertical stress,and excess pore water pressure,but has few effects on temperature.In addition,the vertical displacement,vertical stress,and excess pore water pressure of heterogeneous deep-sea sediments change more gently.The variation trends of physical quantities for heterogeneous and homogeneous deep-sea sediments with frequency and load amplitude are basically the same.The results can provide theoretical guidance for deep-sea mining engineering construction. 展开更多
关键词 heterogeneous deep-sea sediment coupled thermo-hydro-mechanical Green-Lindsay generalized thermoelastic theory normal modal anlalysis dynamic re-sponse
下载PDF
Coupled thermo-hydro-mechanical process in buffer material and self-healing effects with joints 被引量:2
3
作者 YANG Gao-sheng LIU Yue-miao +2 位作者 GAO Yu-feng LI Jian CAI Guo-qing 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第9期2905-2918,共14页
Within the multi-barrier system for high-level waste disposal,the technological gap formed by combined buffer material block becomes the weak part of buffer layer.In this paper,Gaomiaozi bentonite buffer material with... Within the multi-barrier system for high-level waste disposal,the technological gap formed by combined buffer material block becomes the weak part of buffer layer.In this paper,Gaomiaozi bentonite buffer material with technological gap was studied,the heat transfer induced by liquid water flow and water vapor was embedded into the energy conservation equation.Based on the Barcelona basic model,the coupled thermo-hydro-mechanical model of unsaturated bentonite was established by analyzing the swelling process of bentonite block and the compression process of joint material.The China-Mock-up test was adopted to compare the numerical calculation results with the test results so as to verify the rationality of the proposed model.On this basis,the effect of joint self-healing on dry density,thermal conductivity and permeability coefficient of buffer material was further analyzed.The results show that,with bentonite hydrating and swelling,the joint material gradually increases in dry density,and exhibits comparatively uniform hydraulic and thermal conductivity properties as compacted bentonite block.As a result,the buffer material gradually shifts to homogenization due to the coordinated deformation. 展开更多
关键词 buffer material thermo-hydro-mechanical coupling JOINTS self-healing effect
下载PDF
A fully coupled thermo-hydro-mechanical model for unsaturated porous media 被引量:4
4
作者 Weizhong Chen Xianjun Tan Hongdan Yu Guojun Wu Shanpo Jia 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2009年第1期31-40,共10页
In examining potential host rocks for such purposes as the disposal of high-level radioactive wastes,it is important to understand the coupled thermo-hydro-mechanical(THM) behavior of a porous medium.A rigorous and ... In examining potential host rocks for such purposes as the disposal of high-level radioactive wastes,it is important to understand the coupled thermo-hydro-mechanical(THM) behavior of a porous medium.A rigorous and fully unified coupled thermo-hydro-mechanical model for unsaturated porous media is required to simulate the complex coupling mechanisms involved.Based on modified Darcy's and Fourier's laws,equations of mechanical equilibrium,mass conservation and energy conservation are derived by introducing void ratio and volumetric liquid water content into the model.The newly derived model takes into account the effects of temperature on the dynamic viscosity of liquid water and void ratio,the influence of liquid flow on temperature gradient(thermo-osmosis),the influence on mass and heat conservation equations,and the influence of heat flow on water pressure gradient and thermal convection.The new coupled THM constitutive model is constructed by a finite element program and is used to simulate the coupled behavior of a tunnel during excavation,ventilation and concrete lining stages.Oil and gas engineering,underground disposal of nuclear waste and tunnel engineering may be benefited from the development of the new model. 展开更多
关键词 porous media unsaturated media coupled thermo-hydro-mechanical (THM) model
下载PDF
Numerical manifold method modeling of coupled processes in fractured geological media at multiple scales 被引量:4
5
作者 Mengsu Hu Jonny Rutqvist 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第4期667-681,共15页
The greatest challenges of rigorously modeling coupled hydro-mechanical(HM)processes in fractured geological media at different scales are associated with computational geometry.These challenges include dynamic sheari... The greatest challenges of rigorously modeling coupled hydro-mechanical(HM)processes in fractured geological media at different scales are associated with computational geometry.These challenges include dynamic shearing and opening of intersecting fractures at discrete fracture scales as a result of coupled processes,and contact alteration along rough fracture surfaces that triggers structural and physical changes of fractures at micro-asperity scale.In this paper,these challenges are tackled by developing a comprehensive modeling approach for coupled processes in fractured geological media based on numerical manifold method(NMM)at multiple scales.Based on their distinct geometric features,fractures are categorized into three different scales:dominant fracture,discrete fracture,and discontinuum asperity scales.Here the scale is relative,that of the fracture relative to that of the research interest or domain.Different geometric representations of fractures at different scales are used,and different governing equations and constitutive relationships are applied.For dominant fractures,a finite thickness zone model is developed to treat a fracture as a porous nonlinear domain.Nonlinear fracture mechanical behavior is accurately modeled with an implicit approach based on strain energy.For discrete fractures,a zero-dimensional model was developed for analyzing fluid flow and mechanics in fractures that are geometrically treated as boundaries of the rock matrix.With the zero-dimensional model,these fractures can be modeled with arbitrary orientations and intersections.They can be fluid conduits or seals,and can be open,bonded or sliding.For the discontinuum asperity scale,the geometry of rough fracture surfaces is explicitly represented and contacts involving dynamic alteration of contacts among asperities are rigorously calculated.Using this approach,fracture alteration caused by deformation,re-arrangement and sliding of rough surfaces can be captured.Our comprehensive model is able to handle the computational challenges with accurate representation of intersections and shearing of fractures at the discrete fracture scale and rigorously treats contacts along rough fracture surfaces at the discontinuum asperity scale.With future development of three-dimensional(3D)geometric representation of discrete fracture networks in porous rock and contacts among multi-body systems,this model is promising as a basis of 3D fully coupled analysis of fractures at multiple scales,for advancing understanding and optimizing energy recovery and storage in fractured geological media. 展开更多
关键词 Dominant fractures Discrete fractures Discontinuum asperity scale coupled processes Numerical manifold method(NMM)
下载PDF
Coupled thermo-hydro-mechanical simulation of CO2 enhanced gas recovery with an extended equation of state module for TOUGH2MP-FLAC3D 被引量:1
6
作者 Yang Gou Zhengmeng Hou +2 位作者 Mengting Li Wentao Feng Hejuan Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2016年第6期904-920,共17页
As one of the most important ways to reduce the greenhouse gas emission,carbon dioxide(CO2)enhanced gas recovery(CO2-EGR) is attractive since the gas recovery can be enhanced simultaneously with CO2sequestration.B... As one of the most important ways to reduce the greenhouse gas emission,carbon dioxide(CO2)enhanced gas recovery(CO2-EGR) is attractive since the gas recovery can be enhanced simultaneously with CO2sequestration.Based on the existing equation of state(EOS) module of TOUGH2 MP,extEOS7C is developed to calculate the phase partition of H2O-CO2-CH4-NaCl mixtures accurately with consideration of dissolved NaCI and brine properties at high pressure and temperature conditions.Verifications show that it can be applied up to the pressure of 100 MPa and temperature of 150℃.The module was implemented in the linked simulator TOUGH2MP-FLAC3 D for the coupled hydro-mechanical simulations.A simplified three-dimensional(3D)1/4 model(2.2 km×1 km×1 km) which consists of the whole reservoir,caprock and baserock was generated based on the geological conditions of a gas field in the North German Basin.The simulation results show that,under an injection rate of 200,000 t/yr and production rate of 200,000 sm3/d,CO2breakthrough occurred in the case with the initial reservoir pressure of 5 MPa but did not occur in the case of 42 MPa.Under low pressure conditions,the pressure driven horizontal transport is the dominant process;while under high pressure conditions,the density driven vertical flow is dominant.Under the considered conditions,the CO2-EGR caused only small pressure changes.The largest pore pressure increase(2 MPa) and uplift(7 mm) occurred at the caprock bottom induced by only CO2injection.The caprock had still the primary stress state and its integrity was not affected.The formation water salinity and temperature variations of ±20℃ had small influences on the CO2-EGR process.In order to slow down the breakthrough,it is suggested that CO2-EGR should be carried out before the reservoir pressure drops below the critical pressure of CO2. 展开更多
关键词 Carbon dioxide (CO2) enhanced gas recovery (CO2-EGR) CO2 sequestration Equation of state (EOS) coupled thermo-hydro-mechanical (THM) modeling TOUGH2MP-FLAC3D
下载PDF
Comparison of numerical codes for coupled thermo-hydro-mechanical simulations of fractured media
7
作者 Ahmad Zareidarmiyan Hossein Salarirad +3 位作者 Victor Vilarrasa Kwang-Il Kim Jaewon Lee Ki-Bok Min 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2020年第4期850-865,共16页
Geo-energy and geo-engineering applications,such as improved oil recovery(IOR),geologic carbon storage,and enhanced geothermal systems(EGSs),involve coupled thermo-hydro-mechanical(THM)processes that result from fluid... Geo-energy and geo-engineering applications,such as improved oil recovery(IOR),geologic carbon storage,and enhanced geothermal systems(EGSs),involve coupled thermo-hydro-mechanical(THM)processes that result from fluid injection and production.In some cases,reservoirs are highly fractured and the geomechanical response is controlled by fractures.Therefore,fractures should explicitly be included into numerical models to realistically simulate the THM responses of the subsurface.In this study,we perform coupled THM numerical simulations of water injection into naturally fractured reservoirs(NFRs)using CODE_BRIGHT and TOUGH-UDEC codes.CODE_BRIGHT is a finite element method(FEM)code that performs fully coupled THM analysis in geological media and TOUGH-UDEC sequentially solves coupled THM processes by combining a finite volume method(FVM)code that solves nonisothermal multiphase flow(TOUGH2)with a distinct element method(DEM)code that solves the mechanical problem(UDEC).First,we validate the two codes against a semi-analytical solution for water injection into a single deformable fracture considering variable permeability based on the cubic law.Then,we compare simulation results of the two codes in an idealized conceptual model that includes one horizontal fracture and in a more realistic model with multiple fractures.Each code models fractures differently.UDEC calculates fracture deformation from the fracture normal and shear stiffnesses,while CODE_BRIGHT treats fractures as equivalent porous media and uses the equivalent Young’s modulus and Poisson’s ratio of the fracture.Finally,we obtain comparable results of pressure,temperature,stress and displacement distributions and evolutions for the single horizontal fracture model.Despite some similarities,the two codes provide increasingly different results as model complexity increases.These differences highlight the challenging task of accurately modeling coupled THM processes in fractured media given their high nonlinearity. 展开更多
关键词 coupled thermo-hydro-mechanical(THM) analysis Improved oil recovery(IOR) Naturally fractured reservoir(NFR) CODE_BRIGHT TOUGH-UDEC
下载PDF
Progress in Processes and Catalysts for Dehydrogenation of Cyclohexanol to Cyclohexanone
8
作者 Jing Gong Shixin Hou +1 位作者 Yue Wang Xinbin Ma 《Transactions of Tianjin University》 EI CAS 2023年第3期196-208,共13页
The dehydrogenation of cyclohexanol to cyclohexanone is a crucial industrial process in the production of caprolactam and adipic acid, both of which serve as important precursors in nylon textiles. This endothermic re... The dehydrogenation of cyclohexanol to cyclohexanone is a crucial industrial process in the production of caprolactam and adipic acid, both of which serve as important precursors in nylon textiles. This endothermic reaction is constrained by thermodynamic equilibrium and involves a complex reaction network, leading to a heightened focus on catalysts and process design. Copper-based catalysts have been extensively studied and exhibit exceptional low-temperature catalytic performance in cyclohexanol dehydrogenation, with some being commercially used in the industry. This paper specifically concentrates on research advancement concerning active species, reaction mechanisms, factors influencing product selectivity, and the deactivation behaviors of copper-based catalysts. Moreover, a brief introduction to the new processes that break thermodynamic equilibrium via reaction coupling and their corresponding catalysts is summarized here as well. These reviews may off er guidance and potential avenues for further investigations into catalysts and processes for cyclohexanol dehydrogenation. 展开更多
关键词 CYCLOHEXANOL DEHYDROGENATION CYCLOHEXANONE Copper-based catalyst Reaction coupling processes
下载PDF
Formulation of thermo-hydro-mechanical coupling behavior of unsaturated soils based on hybrid mixture theory 被引量:2
9
作者 Guo-Qing Cai Cheng-Gang Zhao +1 位作者 Dai-Chao Sheng An-Nan Zhou 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2014年第4期559-568,共10页
Thermo-Hydro-Mechanical (THM) coupling pro- cesses in unsaturated soils are very important in both theoretical researches and engineering applications. A coupled formulation based on hybrid mixture theory is derived... Thermo-Hydro-Mechanical (THM) coupling pro- cesses in unsaturated soils are very important in both theoretical researches and engineering applications. A coupled formulation based on hybrid mixture theory is derived to model the THM coupling behavior of unsaturated soils. The free-energy and dissipative functions for different phases are derived from Taylor's series expansions. Constitutive relations for THM coupled behaviors of unsaturated soils, which include deformation, entropy change, fluid flow, heat conduction, and dynamic compatibility conditions on the interfaces, are then established. The number of field equations is shown to be equal to the number of unknown variables; thus, a closure of this coupling problem is established. In addition to modifications of the physical conservation equations with coupling effect terms, the constitutive equations, which consider the coupling between elastoplastic deformation of the soil skeleton, fluid flow, and heat transfer, are also derived. 展开更多
关键词 thermo-hydro-mechanical coupling Unsatu-rated soils Hybrid mixture theory Constitutive equations ·Elastoplastic deformation
下载PDF
Variations and relations between chlorophyll concentrations and physical-ecological processes near the West Antarctic Peninsula
10
作者 WU Shuang ZHANG Zhaoru WANG Chuning 《Advances in Polar Science》 CSCD 2023年第4期262-271,共10页
The West Antarctic Peninsula(WAP)region is one of the most productive marine ecosystems in the Southern Ocean that support the food web for phytoplankton,krill spawning or recruitment and several krill consumers at hi... The West Antarctic Peninsula(WAP)region is one of the most productive marine ecosystems in the Southern Ocean that support the food web for phytoplankton,krill spawning or recruitment and several krill consumers at higher-trophic level like penguins and Antarctic fur seals.Characterized by channels and islands,the complex topography of the WAP generates interconnected circulation patterns,strongly influencing vertical stratification,nutrient availability and distribution of marine organisms.Additionally,rapid climate change associated with major climate modes like the Southern Annular Mode(SAM)and El Niño-Southern Oscillation(ENSO)has significant effects on long-term variations of physical environments and biological production.The objective of this study is to reveal the spatial-temporal variations of phytoplankton biomass in the WAP region and the modulating physical-ecological processes.By using 9-year hydrographic and ecological data of five transects collected by the Palmer Long-Term Ecosystem Research,the horizontal and vertical distributions of several physical and ecological properties,with a particular focus on chlorophyll(Chl)concentration were explored.Regression analysis among area-averaged properties and properties at single stations was performed to reveal the relationship between the interannual variations of physical and ecological processes.The correlation results showed that Chl concentration exhibited a positive relationship with both the circumpolar deep water(CDW)intrusion and vertical stratification,but showed a negative correlation with SAM at some specific stations.However,certain processes or mechanisms may only be dominant for specific stations and not applicable to the entire region.No single physical or ecological factors have been found to significantly influence the Chl distribution throughout the WAP region,which may be attributed to the heterogeneity of sea ice conditions,geometry and hydrodynamic features as well as variations in nutrient sources. 展开更多
关键词 West Antarctic Peninsula phytoplankton productivity temporal-spatial variations physical-ecological coupling processes
下载PDF
Simulation of coupled THM process in surrounding rock mass of nuclear waste repository in argillaceous formation 被引量:1
11
作者 蒋中明 HOXHA Dashnor +1 位作者 HOMAND Fran?oise 陈永贵 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第2期631-637,共7页
To investigate and analyze the thermo-hydro-mechanical(THM) coupling phenomena of a surrounding rock mass in an argillaceous formation, a nuclear waste disposal concept in drifts was represented physically in an in-si... To investigate and analyze the thermo-hydro-mechanical(THM) coupling phenomena of a surrounding rock mass in an argillaceous formation, a nuclear waste disposal concept in drifts was represented physically in an in-situ test way. A transversely isotropic model was employed to reproduce the whole test process numerically. Parameters of the rock mass were determined by laboratory and in-situ experiments. Based on the numerical simulation results and in-situ test data, the variation processes of pore water pressure, temperature and deformation of surrounding rock were analyzed. Both the measured data and numerical results reveal that the thermal perturbation is the principal driving force which leads to the variation of pore water pressure and deformations in the surrounding rock. The temperature, pore pressure and deformation of rock mass change rapidly at each initial heating stage with a constant heating power. The temperature field near the heater borehole is relatively steady in the subsequent stages of the heating phase. However, the pore pressure and deformation fields decrease gradually with temperature remaining unchanged condition. It also shows that a transversely isotropic model can reproduce the THM coupling effects generating in the near-field of a nuclear waste repository in an argillaceous formation. 展开更多
关键词 argillaceous formation thermo-hydro-mechanical(THM) process in-situ test
下载PDF
AN ADAPTIVE EFG-FE COUPLING METHOD FOR THE NUMERICAL SIMULATION OF EXTRUSION PROCESSES
12
作者 L.C. Liu X.H. Doug C.X. Li 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2008年第5期380-388,共9页
An adaptive EFG-FE coupling method is proposed and developed for the numerical simulation of lateral extrusion and forward-backward extrusion. Initially, the simulation has been implemented by using a conventional FE ... An adaptive EFG-FE coupling method is proposed and developed for the numerical simulation of lateral extrusion and forward-backward extrusion. Initially, the simulation has been implemented by using a conventional FE model. During the deforming process, mesh quality is checked at every incremental step. Distorted elements are automatically converted to EFG nodes, whereas, the less distorted elements are reserved. A new algorithm to generate EFG nodes and interface elements is presented. This method is capable of dealing with large deformation and has higher computational efficiency than using an EFG method wholly. Numerical results demonstrate that the adaptive EFG-FE coupling method has reasonable accuracy and is effective for local bulk metal forming such as extrusion processes. 展开更多
关键词 Meshless method coupling method Numerical simulation Extrusion process
下载PDF
ANALYSIS OF THE THERMOPHYSICAL PARAMETERS OF MOIST WOOD PARTICLE MATERIAL IN A COUPLED HEAT AND MASS TRANSFER PROCESS OF FREEZING BY USING FINITE ELEMENT METHOD
13
作者 Shang DekuNortheast Forestry University 《Journal of Northeast Forestry University》 SCIE CAS CSCD 1991年第2期69-76,共8页
The coupled heat and moisture transfer in a freezing process of wood particle material was mathematically modeled in the paper. The models were interactively solved by using the numerical method(the finite element met... The coupled heat and moisture transfer in a freezing process of wood particle material was mathematically modeled in the paper. The models were interactively solved by using the numerical method(the finite element method and the finite difference method). By matching the theoretical calculation to an experiment, the nonlinear problem was analyzed and the variable thermophysical parameters concerned was evaluated. The analysis procedure and the evaluation of the parameters were presented in detail. The result of the study showed that by using the method as described in the paper, it was possible to determine the variable (with respect to temperature, moisture content and freezing state) thermophysical parameters which were unknown or difficult to measure as long as the governing equations for a considered process were available. The method can significantly reduces the experiment efforts for determining thermophysical parameters which arc very complicated to measure. The determined variable of the effective heat conductivity of wood particle material was given in the paper. The error of the numerical calculation was also estimated by the comparison with a matched experiment. 展开更多
关键词 Finite element method Freezing process coupled heat and mass transfer Variable thermophysical parameters
下载PDF
FEM analyses for influences of pressure solution on thermo-hydro-mechanical coupling in porous rock mass
14
作者 张玉军 杨朝帅 《Journal of Central South University》 SCIE EI CAS 2012年第8期2333-2339,共7页
The model of pressure solution for granular aggregate was introduced into the FEM code for analysis of thermo-hydro- mechanical (T-H-M) coupling in porous medium. Aiming at a hypothetical nuclear waste repository in... The model of pressure solution for granular aggregate was introduced into the FEM code for analysis of thermo-hydro- mechanical (T-H-M) coupling in porous medium. Aiming at a hypothetical nuclear waste repository in an unsaturated quartz rock mass, two computation conditions were designed: 1) the porosity and the permeability of rock mass are fimctions of pressure solution; 2) the porosity and the permeability are constants. Then the corresponding numerical simulations for a disposal period of 4 a were carried out, and the states of temperatures, porosities and permeabilities, pore pressures, flow velocities and stresses in the rock mass were investigated. The results show that at the end of the calculation in Case 1, pressure solution makes the porosities and the permeabilities decrease to 10%-45% and 0.05%-1.4% of their initial values, respectively. Under the action of the release heat of nuclear waste, the negative pore pressures both in Case 1 and Case 2 are 1.2-1.4 and 1.01-l.06 times of the initial values, respectively. So, the former represents an obvious effect of pressure solution. The magnitudes and distributions of stresses within the rock mass in the two calculation cases are the same. 展开更多
关键词 pressure solution porous medium thermo-hydro-mechanical coupling FEM analysis
下载PDF
The effects of process conditions on the plasma characteristic in radio-frequency capacitively coupled SiH_4/NH_3/N_2 plasmas: Two-dimensional simulations
15
作者 刘相梅 宋远红 +1 位作者 姜巍 易林 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第4期338-343,共6页
A two-dimensional (2D) fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma (CCP) reactor. The plasma–wall interaction ... A two-dimensional (2D) fluid model is presented to study the behavior of silicon plasma mixed with SiH4 , N2 , and NH3 in a radio-frequency capacitively coupled plasma (CCP) reactor. The plasma–wall interaction (including the deposition) is modeled by using surface reaction coefficients. In the present paper we try to identify, by numerical simulations, the effect of variations of the process parameters on the plasma properties. It is found from our simulations that by increasing the gas pressure and the discharge gap, the electron density profile shape changes continuously from an edge-high to a center-high, thus the thin films become more uniform. Moreover, as the N2 /NH3 ratio increases from 6/13 to 10/9, the hydrogen content can be significantly decreased, without decreasing the electron density significantly. 展开更多
关键词 capacitively coupled plasma process conditions effects SiH4/NH3/N2 discharges
下载PDF
Rheological numerical simulation for thermo-hydro-mechanical coupling analysis for rock mass
16
作者 王芝银 许杰 +2 位作者 李云鹏 郭书太 艾传志 《Journal of Coal Science & Engineering(China)》 2007年第2期135-139,共5页
Under the environment of seepage field, stress field and temperature field interaction and influence, the three fields will not only produce coupling effect, but also have deformation with time due to the rheological ... Under the environment of seepage field, stress field and temperature field interaction and influence, the three fields will not only produce coupling effect, but also have deformation with time due to the rheological behavior of rock mass. In the paper, based on the fundamental theories of rock mass coupling theory and rheological mechanics, the rheological model for fully coupled thermo-hydro-mechanical analysis for rock mass was set up, and the corresponding constitutive relationship, the conservation equation of mass and the conservation equation of energy were given, and the finite element formulas were derived for coupling analysis of rock mass. During establishing governing equations, rock mass was assumed approximately as macro-equivalent continuum medium. The obtained rheological numerical model for fully coupled thermo-hydro-mechanical analysis can be used for analyzing and predicting the long-term stability of underground caverns and slope engineering under the condition of thermo-hydro-mechanical coupling with rheological deformation. 展开更多
关键词 thermo-hydro-mechanical coupling rheological analysis FEM model rockmass
下载PDF
Effects of Tensor Couplings on Nucleonic Direct URCA Processes in Neutron Star Matter
17
作者 许妍 黄修林 +2 位作者 刘承志 特木尔巴根 刘广洲 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第9期132-135,共4页
The relativistic neutrino emissivity of the nucleonic direct URCA processes in neutron star matter is investigated within the relativistic Hartree-Fock approximation. We particularly study the influences of the tensor... The relativistic neutrino emissivity of the nucleonic direct URCA processes in neutron star matter is investigated within the relativistic Hartree-Fock approximation. We particularly study the influences of the tensor couplings of vector mesons ω and ρ on the nucleonic direct URCA processes. It is found that the inclusion of the tensor couplings of vector mesons w and p can slightly increase the maximum mass of neutron stars. In addition, the results indicate that the tensor couplings of vector mesons ω and ρ lead to obvious enhancement of the total neutrino emissivity for the nucleonic direct URCA processes, which must accelerate the cooling rate of the non- superfluid neutron star matter. However, when considering only the tensor coupling of vector meson ρ, the neutrino emissivity for the nucleonic direct URCA processes slightly declines at low densities and significantly increases at high densities. That is, the tensor coupling of vector meson ρ leads to the slow cooling rate of a low-mass neutron star and rapid cooling rate of a massive neutron star. 展开更多
关键词 of is it for Effects of Tensor couplings on Nucleonic Direct URCA processes in Neutron Star Matter in on
下载PDF
The etching process and mechanism analysis of Ta-Sb2Te3 film based on inductively coupled plasma
18
作者 Yongkang Xu Sannian Song +2 位作者 Wencheng Fang Chengxing Li Zhitang Song 《Journal of Semiconductors》 EI CAS CSCD 2020年第12期12-16,共5页
Compared to the conventional phase change materials,the new phase change material Ta-Sb2Te3 has the advantages of excellent data retention and good material stability.In this letter,the etching characteristics of Ta-S... Compared to the conventional phase change materials,the new phase change material Ta-Sb2Te3 has the advantages of excellent data retention and good material stability.In this letter,the etching characteristics of Ta-Sb2Te3 were studied by using CF4/Ar.The results showed that when CF4/Ar=25/25,the etching power was 600 W and the etching pressure was 2.5 Pa,the etching speed was up to 61 nm/min.The etching pattern of Ta-Sb2Te3 film had a smooth side wall and good perpendicularity(close to 90°),smooth surface of the etching(RMS was 0.51nm),and the etching uniformity was fine.Furthermore,the mechanism of this etching process was analyzed by X-ray photoelectron spectroscopy(XPS).The main damage mechanism of ICP etching in CF4/Ar was studied by X-ray diffraction(XRD). 展开更多
关键词 new phase change material inductively couple plasma etching process etching characteristics mechanism
下载PDF
Entanglement and decoherence of coupled superconductor qubits in a non-Markovian environment 被引量:3
19
作者 嵇英华 胡菊菊 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第6期46-51,共6页
The sudden death of entanglement is investigated for the non-Markovian dynamic process of a pair of interacting flux qubits under a thermal bath. The results show that, for initially two-qubit entangled states, entang... The sudden death of entanglement is investigated for the non-Markovian dynamic process of a pair of interacting flux qubits under a thermal bath. The results show that, for initially two-qubit entangled states, entanglement sudden death (ESD) always happens in the thermal reservoir, where its appearance strongly depends on the environment. In particular, ESD of the qubits occurs more easily for the non-Markovian process than for the Markovian one. 展开更多
关键词 ENTANGLEMENT coupled qubits non-Markovian process CONCURRENCE
下载PDF
Simulations of THM processes in buffer-rock barriers of high-level waste disposal in an argillaceous formation 被引量:2
20
作者 Xiaoshuo Li Chunliang Zhang Klaus-Jürgen Rhlig 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2013年第4期277-286,共10页
The main objective of this paper is to investigate and analyse the thermo-hydro-mechanical(THM) coupling phenomena and their influences on the repository safety.In this paper,the high-level waste(HLW) disposal con... The main objective of this paper is to investigate and analyse the thermo-hydro-mechanical(THM) coupling phenomena and their influences on the repository safety.In this paper,the high-level waste(HLW) disposal concept in drifts in clay formation with backfilled bentonite buffer is represented numerically using the CODE BRIGHT developed by the Technical University of Catalonia in Barcelona.The parameters of clay and bentonite used in the simulation are determined by laboratory and in situ experiments.The calculation results are presented to show the hydro-mechanical(HM) processes during the operation phase and the THM processes in the after-closure phase.According to the simulation results,the most probable critical processes for the disposal project have been represented and analyzed.The work also provides an input for additional development regarding the design,assessment and validation of the HLW disposal concept. 展开更多
关键词 thermo-hydro-mechanical(THM) coupling processes Clay formation Unsaturated porous media Bentonite buffer CODE BRIGHT
下载PDF
上一页 1 2 93 下一页 到第
使用帮助 返回顶部