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Analysis on the law of occurrence of shallow geothermal energy in Zhoukou City of Henan Province,China 预览
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作者 XING Hui DI Yan-song YONG Yi 《地下水科学与工程:英文版》 2019年第3期282-287,共6页
In this paper,through data collection and field investigation,the development and utilization status of shallow geothermal energy in Zhoukou urban area was discussed.Based on the analysis of hydrogeological conditions... In this paper,through data collection and field investigation,the development and utilization status of shallow geothermal energy in Zhoukou urban area was discussed.Based on the analysis of hydrogeological conditions,rock and soil structure characteristics and field test research,the spatial distribution characteristics of rock and soil in the study area were summarized.The study shows that Zhoukou City is located in the alluvial plain of Huanghuai,and the loose deposits of river alluvial genesis range 0-200 m.These loose deposits and groundwater stored in their pores are the main carriers of shallow geothermal energy.In the central part of the Yinghe River in the middle of the study area,the aquifer thickness is within 200 m,the particle size is coarser,the water-bearing degree and recharge capacity is better.On this basis,the paper uses AHP to evaluate the suitability of shallow geothermal energy development and utilization to guide the rational development and utilization of shallow geothermal energy resources. 展开更多
关键词 Zhoukou CITY SHALLOW GEOTHERMAL energy Thermal physical characteristics Water ABUNDANCE Ability of recirculation SHALLOW GEOTHERMAL area
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The role of carbonate-fluoride melt immiscibility in shallow REE deposit evolution 预览
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作者 Jindrich Kynicky Martin P.Smith +5 位作者 Wenlei Song Anton R.Chakhmouradian Cheng Xu Antonin Kopriva Michaela Vasinova Galiova Martin Brtnicky 《地学前缘:英文版》 CAS CSCD 2019年第2期527-537,共11页
The Lugiin Gol nepheline syenite intrusion,Mongolia,hosts a range of carbonatite dikes mineralized in rare-earth elements(REE).Both carbonatites and nepheline syenite-fluorite-calcite veinlets are host to a previously... The Lugiin Gol nepheline syenite intrusion,Mongolia,hosts a range of carbonatite dikes mineralized in rare-earth elements(REE).Both carbonatites and nepheline syenite-fluorite-calcite veinlets are host to a previously unreported macroscale texture involving pseudo-graphic intergrowths of fluorite and calcite.The inclusions within calcite occur as either pure fluorite,with associated REE minerals within the surrounding calcite,or as mixed calcite-fluorite inclusions,with associated zirconosilicate minerals.Consideration of the nature of the texture,and the proportions of fluorite and calcite present(~29 and 71 mol%,respectively),indicates that these textures most likely formed either through the immiscible separation of carbonate and fluoride melts,or from cotectic crystallization of a carbonatefluoride melt.Laser ablation ICP-MS analyses show the pure fluorite inclusions to be depleted in REE relative to the calcite.A model is proposed,in which a carbonate-fluoride melt phase enriched in Zr and the REE,separated from a phonolitic melt,and then either unmixed or underwent cotectic crystallization to generate an REE-rich carbonate melt and an REE-poor fluoride phase.The separation of the fluoride phase(either solid or melt)may have contributed to the enrichment of the carbonate melt in REE,and ultimately its saturation with REE minerals.Previous data have suggested that carbonate melts separated from silicate melts are relatively depleted in the REE,and thus melt immiscibility cannot result in the formation of REE-enriched carbonatites.The observations presented here provide a mechanism by which this could occur,as under either model the textures imply initial separation of a mixed carbonate-fluoride melt from a silicate magma.The separation of an REEenriched carbonate-fluoride melt from phonolitic magma is a hitherto unrecognized mechanism for REE-enrichment in carbonatites,and may play an important role in the formation of shallow magmatic REE deposits. 展开更多
关键词 Silicate-carbonate-fluoride MELT IMMISCIBILITY Carbonatite Alkaline SYENITE SHALLOW REE deposit Lugiin Gol Mongolia
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Effects of rough surface on sound propagation in shallow water
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作者 刘若芸 李整林 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期423-430,共8页
Underwater acoustic applications depend critically on the prediction of sound propagation, which can be significantly affected by a rough surface, especially in shallow water. This paper aims to investigate how random... Underwater acoustic applications depend critically on the prediction of sound propagation, which can be significantly affected by a rough surface, especially in shallow water. This paper aims to investigate how randomly fluctuating surface influences transmission loss(TL) in shallow water. The one-dimension wind-wave spectrum, Monterey–Miami parabolic equation(MMPE) model, Monte Carlo method, and parallel computing technology are combined to investigate the effects of different sea states on sound propagation. It is shown that TL distribution properties are related to the wind speed,frequency, range, and sound speed profile. In a homogenous waveguide, with wind speed increasing, the TLs are greater and more dispersive. For a negative thermocline waveguide, when the source is above the thermocline and the receiver is below that, the effects of the rough surface are the same and more significant. When the source and receiver are both below the thermocline, the TL distributions are nearly the same for different wind speeds. The mechanism of the different TL distribution properties in the thermocline environment is explained by using ray theory. In conclusion, the statistical characteristics of TL are affected by the relative roughness of the surface, the interaction strength of the sound field with the surface, and the changes of propagating angle due to refraction. 展开更多
关键词 SURFACE FLUCTUATION SHALLOW water TRANSMISSION LOSS STATISTICAL characteristics
Lattice Boltzmann method for simulating flows in open-channel with partial emergent rigid vegetation cover 预览
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作者 Zhong-hua Yang Feng-peng Bai +1 位作者 Wen-xin Huai Cheng-guang Li 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第4期717-724,共8页
Flows in open-channel with partial emergent rigid vegetation cover are simulated using the lattice Boltzmann method (LBM) described by the 2-D nonlinear shallow water equations. The effect of vegetation is represented... Flows in open-channel with partial emergent rigid vegetation cover are simulated using the lattice Boltzmann method (LBM) described by the 2-D nonlinear shallow water equations. The effect of vegetation is represented with the vegetation roughness coefficient, which is related to the vegetation density, diameter of the vegetation elements and drag coefficient. The model is verified by three numerical tests: flow in a 180° curved open channel with partial vegetation cover at the outer bank, flow in a rectangular channel with a finite patch of vegetation and flow in a rectangular channel with a vegetated bank. Numerical results are compared with the experimental data, and the good agreement proved that the presented model can model the vegetated channel flows correctly. 展开更多
关键词 Open-channel flow RIGID VEGETATION lattice BOLTZMANN method (LBM) shallow water equations VEGETATION ROUGHNESS coefficient
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Numerical storm surge model with higher order finite difference method of lines for the coast of Bangladesh 预览
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作者 Gour Chandra Paul Md. Emran Ali 《海洋学报:英文版》 SCIE CAS CSCD 2019年第6期100-116,共17页
In this study, the method of lines (MOLs) with higher order central difference approximation method coupled with the classical fourth order Runge-Kutta (RK(4,4)) method is used in solving shallow water equations (SWEs... In this study, the method of lines (MOLs) with higher order central difference approximation method coupled with the classical fourth order Runge-Kutta (RK(4,4)) method is used in solving shallow water equations (SWEs) in Cartesian coordinates to foresee water levels associated with a storm accurately along the coast of Bangladesh. In doing so, the partial derivatives of the SWEs with respect to the space variables were discretized with 5-point central difference, as a test case, to obtain a system of ordinary differential equations with time as an independent variable for every spatial grid point, which with initial conditions were solved by the RK(4,4) method. The complex land-sea interface and bottom topographic details were incorporated closely using nested schemes. The coastal and island boundaries were rectangularized through proper stair step representation, and the storing positions of the scalar and momentum variables were specified according to the rules of structured C-grid. A stable tidal regime was made over the model domain considering the effect of the major tidal constituent, M2 along the southern open boundary of the outermost parent scheme. The Meghna River fresh water discharge was taken into account for the inner most child scheme. To take into account the dynamic interaction of tide and surge, the generated tidal regime was introduced as the initial state of the sea, and the surge was then made to come over it through computer simulation. Numerical experiments were performed with the cyclone April 1991 to simulate water levels due to tide, surge, and their interaction at different stations along the coast of Bangladesh. Our computed results were found to compare reasonable well with the limited observed data obtained from Bangladesh Inland Water Transport Authority (BIWTA) and were found to be better in comparison with the results obtained through the regular finite difference method and the 3-point central difference MOLs coupled with the RK(4,4) method with regard to the root mean square er 展开更多
关键词 SHALLOW water equations METHOD of lines higher order finite difference approximation METHOD SURGE nested scheme
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Progress in Global Gas Hydrate Development and Production as a New Energy Resource 预览
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作者 LIU Liping SUN Zhilei +10 位作者 ZHANG Lei WU Nengyou Yichao Qin JIANG Zuzhou GENG Wei CAO Hong ZHANG Xilin ZHAI Bin XU Cuiling SHEN Zhicong JIA Yonggang 《地质学报:英文版》 SCIE CAS CSCD 2019年第3期731-755,共25页
Natural gas hydrates have been hailed as a new and promising unconventional alternative energy,especially as fossil fuels approach depletion,energy consumption soars,and fossil fuel prices rise,owing to their extensiv... Natural gas hydrates have been hailed as a new and promising unconventional alternative energy,especially as fossil fuels approach depletion,energy consumption soars,and fossil fuel prices rise,owing to their extensive distribution,abundance,and high fuel efficiency.Gas hydrate reservoirs are similar to a storage cupboard in the global carbon cycle,containing most of the world's methane and accounting for a third of Earth's mobile organic carbon.We investigated gas hydrate stability zone burial depths from the viewpoint of conditions associated with stable existence of gas hydrates,such as temperature,pressure,and heat flow,based on related data collected by the global drilling programs.Hydrate-related areas are estimated using various biological,geochemical and geophysical tools.Based on a series of previous investigations,we cover the history and status of gas hydrate exploration in the USA,Japan,South Korea,India,Germany,the polar areas,and China.Then,we review the current techniques for hydrate exploration in a global scale.Additionally,we briefly review existing techniques for recovering methane from gas hydrates,including thermal stimulation,depressurization,chemical injection,and CH4-CO2 exchange,as well as corresponding global field trials in Russia,Japan,United States,Canada and China.In particular,unlike diagenetic gas hydrates in coarse sandy sediments in Japan and gravel sediments in the United States and Canada,most gas hydrates in the northem South China Sea are non-diagenetic and exist in fine-grained sediments with a vein-like morphology.Therefore,especially in terms of the offshore production test in gas hydrate reservoirs in the Shenhu area in the north slope of the South China Sea,Chinese scientists have proposed two unprecedented techniques that have been verified during the field trials:solid fluidization and formation fluid extraction.Herein,we introduce the two production techniques,as well as the so-called"fbur-in-one"environmental monitoring system employed during the Shenhu production te 展开更多
关键词 natural GAS HYDRATE GAS RECOVERY PRODUCTION technique SHALLOW GAS HYDRATE environmental monitoring
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Anse Intendance沙滩
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《中国投资》 2019年第14期50-53,共4页
位于马埃岛南部的Anse Intendance是马埃岛上最具名气的沙滩,在这里,可以享受世界级的日光浴.冲浪爱好者也可以享受乘风踏浪的快感.而运气好的话,每逢黄昏,人们还可以在浅水处邂逅海豚。
关键词 马埃岛 光浴 沙滩 日光浴
榆林市浅层地热能资源量调查评价研究 预览
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作者 王克 周阳 江星辰 《节能》 2019年第2期101-103,共3页
浅层地热能作为新能源,具有分布范围广、可重复利用、对环境无污染等优势。在调查榆林市工程地质条件、水文地质条件的基础上,利用层次分析法,建立了地埋管热泵适宜分区评价体系,对榆林市浅层地热资源开发利用的适宜性进行了分区与评价... 浅层地热能作为新能源,具有分布范围广、可重复利用、对环境无污染等优势。在调查榆林市工程地质条件、水文地质条件的基础上,利用层次分析法,建立了地埋管热泵适宜分区评价体系,对榆林市浅层地热资源开发利用的适宜性进行了分区与评价。计算了浅层地热能适宜区的热容量、换热功率以及潜力评价。为榆林市科学合理开发利用浅层地热资源提供了理论和数据支撑。 展开更多
关键词 浅层 地热能 资源量 评价
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Comparison of woody species composition between rocky outcrops and nearby matrix vegetation on degraded karst hillslopes of Southwest China 预览
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作者 Yunpeng Nie Yali Ding +1 位作者 Huiling Zhang Hongsong Chen 《林业研究:英文版》 CAS CSCD 2019年第3期911-920,共10页
Habitats with different features such as soil depth and soil/rock conditions can provide favorable environments for species with different requirements, while anthropogenic disturbances normally exert additional effec... Habitats with different features such as soil depth and soil/rock conditions can provide favorable environments for species with different requirements, while anthropogenic disturbances normally exert additional effects on species composition. However, specific studies have rarely been conducted in the degraded karst regions of Southwest China despite the high heterogeneity of karst habitats and past human disturbances. In this study, woody species richness and composition on rocky outcrops on a typical karst hillslope were investigated and compared with those of nearby matrices on shallow and rocky soil. Our results showed that matrix vegetation was more diverse in genera and species than vegetation on rocky outcrops. This might relate to the contrasting substrate features and different disturbance histories of these two habitats. Unlike the significant effect of slope on species richness of the matrix vegetation, rocky outcrops exhibited no significant differences between upper and lower slope positions, largely because their microhabitats were similar in different slope positions. Although the study area has been reforested naturally for about 30 years, woody species of the matrix vegetation were still dominated by pioneer shrub species. Rocky outcrops were dominated by late-successional tree species, which was primarily related to their isolated features and resistance to certain disturbances. Most of these late-successional species were not habitat endemics, indicating the possibility for their encroachment into surrounding the matrix. From this aspect, further studies will be necessary to identify and address the limiting factors for the encroachment of these late-successional species into the surrounding environment. 展开更多
关键词 HABITAT Shallow soil ANTHROPOGENIC disturbance Late-successional SPECIES SPECIES richness
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Numerical investigation of the effects of aquatic plants on wind-induced currents in Taihu Lake in China 预览
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作者 Tian-ping Xu Ming-liang Zhang +3 位作者 Hcng-zhi Jiang Jun Tang Hong-xing Zhang Hui-ting Qiao 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第4期778-787,共10页
Shallow lakes are an important part of the earth's water circulation system, and many factors may impact the evolution of the lake water circulation, including the wind, the topography, the human activities, and t... Shallow lakes are an important part of the earth's water circulation system, and many factors may impact the evolution of the lake water circulation, including the wind, the topography, the human activities, and the aquatic plants. This paper proposes a depth-averaged 2-D hydrodynamic model to investigate the interaction of the wind-induced current and the aquatic plant in the lake. The model is based on the generalized shallow water equations solved by an explicit finite volume method with unstructured triangular grids. The drag force of the vegetation is considered into the momentum equations as the source term. Remote sensing techniques are applied to evaluate the aquatic vegetation in the Taihu Lake, China, based on Landsat TM satellite images. The study model is then used to simulate the characteristics of the wind-induced currents in the Taihu Lake, without and with the vegetation effects. The simulation results are in good agreement with the field measurements, demonstrating that the aquatic plants significantly affect the magnitude of the velocity and the flow circulation induced by the wind in the Taihu Lake. In addition, a sensitivity analysis reveals that the plant parameters (the density and the drag force coefficient) are significant factors influencing the velocity and the structure of the currents in the Taihu Lake. 展开更多
关键词 Finite volume method ROE SOLVER shallow lake wind-induced current AQUATIC plant
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Eco-morphological characteristics of fern species for slope conservation
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作者 Laura SANCHEZ-CASTILLO Ken’ichirou KOSUGI +1 位作者 Naoya MASAOKA Tetsuya KUBOTA 《山地科学学报:英文版》 SCIE CSCD 2019年第3期504-515,共12页
Degradation of slopes due to shallow landslide and the subsequent erosional processes are a big challenge on the application of soil bioengineering techniques;that is the use of plants as main structural components of... Degradation of slopes due to shallow landslide and the subsequent erosional processes are a big challenge on the application of soil bioengineering techniques;that is the use of plants as main structural components of a slope protection and conservation system. An optimal application of soil bioengineering techniques should include not only the technical factor of plants as structural components but also the ecology of species and the plant adaptations to disturbances, which is crucial if a longterm successful slope restoration system is intended. Ferns are a dominant understory vegetation species in the forest of Japan, but its characteristics and influences on the recovery of shallow landslide scars have not been fully studied yet. This study aims to find out the ecological characteristics of fern species through the calculation of ecological indicators and the quantification of the morphological features of specimens growing on disturbed and non-disturbed forest slopes in Japan. Gleichenia japonica was found as the vegetation species with biggest ecological indicators on both slopes. The analysis of morphological characteristics of the specimens growing on both sites showed that the development of the specimens is focused in below-ground characteristics. The pull-out force of Gleichenia japonica root system as an indicator of ecological adaptation to a constraint environment and morphological characteristics quality is influenced by height and root length according to the principal component analysis. The eco-morphological characteristics of species can be used as an indicator of an optimal element in soil bioengineering establishment for slope conservation proposes. The long and fibrous root system could be placed on forest roads, steep or small slopes where space limitation is an issue for the establishment of bigger species and if the slope conditions allow it, it can control soil losses due to rainfall and provide stability. 展开更多
关键词 SLOPE CONSERVATION Soil BIOENGINEERING Root system SHALLOW LANDSLIDE Natural regeneration
Eocene foraminiferal biofacies in Kutch Basin (India) in context of palaeoclimate and palaeoecology
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作者 Sonal Khanolkar Pratul Kumar Saraswati 《古地理学报:英文版》 CSCD 2019年第3期209-224,共16页
The Eocene Epoch passed through multiple hyperthermal events and recorded highest temperatures in the Cenozoic. Very few studies from Eocene palaeotropical sites have recorded changes in shallow marine foraminiferal a... The Eocene Epoch passed through multiple hyperthermal events and recorded highest temperatures in the Cenozoic. Very few studies from Eocene palaeotropical sites have recorded changes in shallow marine foraminiferal assemblages. The present study investigates the foraminiferal biofacies of shallow marine successions from a palaeotropical site in western India (Kutch Basin) to understand the palaeoclimate and its impact on the ecology of foraminifera. The sections were biostratigraphically con strained using planktic and larger benthic foraminifera. Four biofacies are recognized by detrended correspondence analysis of the sample-wise distribution of foraminifera. Low diversity and dwarfed foraminifera characterize Bulimina-Chiloguembelino biofacies (SBZ5/6-SBZ10), corresponding to the interval of Paleocene-Eocene Thermal Maxima (PETM) and Eocene Thermal Maxima 2 (ETM 2). Rectilinear benthic foraminifera and biserial and triserial planktic foraminifera, typical of high runoff, upwelling or eutrophic conditions, are dominant taxa in this biofacies. The specialist taxa increased significantly in Asterigerina-Cibicides biofacies, corresponding to SBZ11 (Early Eocene Climatic Optimum, EECO), and the environment became oligotrophic. The Jenkinsina-Brizalina biofacies (E12) is distinguished by foraminiferal assemblage ecologically like that of Bulimina-Chiloguembelina biofacies. It is characterized by high abundance of rectilinear benthic foraminifera and bloom of triserial planktic foraminifera, suggesting eutrophy and high runoff at the initiation of Middle Eocene Climatic Optimum (MECO). The foraminifera were more diverse and abundant in Cibicides-Nonion biofacies. The highly diverse larger benthic foraminiferal assemblage in this biofacies, signify warm and clear-water oligotrophic sea that promoted the development of platform carbonate in Kutch Basin and other basins in western India. The EECO and MECO did not have an adverse impact on shallow marine foraminifera, and particularly the larger benthic foraminifera att 展开更多
关键词 Hyperthermal events Shallow marine Morphogroups Carbonate platform Stable isotopes EOCENE KUTCH BASIN
Development characteristics and controlling factor analysis of the Neogene Minghuazhen Formation shallow water delta in Huanghekou area, Bohai offshore basin
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作者 Li-Xin Tian Hao Liu +4 位作者 Cheng-Min Niu Xiao-Feng Du Bo Yang Xiao-Dong Lan Dan-Lei Chen 《古地理学报:英文版》 CSCD 2019年第3期251-269,共19页
Based on a combination of high resolution 3-D seismic, drilling and well logging and core data, this study focuses on describing the depositional features of the Neogene Minghuazhen Formation shallow water delta in Hu... Based on a combination of high resolution 3-D seismic, drilling and well logging and core data, this study focuses on describing the depositional features of the Neogene Minghuazhen Formation shallow water delta in Huanghekou area(HHKA), Bohai offshore basin and discussing the evolution and controlling factors of shallow water delta sandbody. An obvious meandering fluvial delta system developed in sequence 1(SQ1) of the Neogene in HHKA with thinner sandbody of distributary channels and poor development of mouth bar. The sequence texture obviously influences the vertical development and stacking pattern of sandbodies and controls the distribution of sandbodies in plain view as well. In shallow water lacustrine basins, relative topographic height difference leads to change of distribution of accommodation space, and sandbodies of distributary channels usually develop well in local low-lying areas where accommodation space increases. The delta is dominated by distributary channel sandbodies during the early period of base level rising. Sandbodies contact with each other in a lateral stacking pattern and are characterized by a fan shape in plain view. Distributary channels gradually narrow and tend to shift during the mid-late-period of base level rising, while the sandbodies are characterized by a net shape in plain view. During the period of base level slow falling, the multistory/multilateral channel sandbodies dominated the inner front of shallow-water delta and the delta sand dispersal distributes as a lobe shape. 展开更多
关键词 The NEOGENE Minghuazhen Formation Huanghekou area Bohai OFFSHORE BASIN SHALLOW water delta Micro-palaeogeomorphology Base level Sandbody STACKING pattern
Influence of Vertical Inertia Force of Covering Soil on Seismic Damage Response of Shallow Buried Underground Frame Structure Shaking Table Model Test of Centrifuge 预览
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作者 Feiyang Qin 《智能建筑研究》 2019年第1期90-105,共16页
The existing research shows that the lateral deformation capacity of the middle column under different axial compression ratios is the key factor affecting the seismic performance of the shallow-buried frame subway st... The existing research shows that the lateral deformation capacity of the middle column under different axial compression ratios is the key factor affecting the seismic performance of the shallow-buried frame subway station structure. In order to study the influence of the increase of axial compression ratio of columns caused by vertical earthquake on the seismic damage response of shallow-buried underground frame structures, a centrifuge shaking table model test for seismic damage of underground structures was carried out by adding steel sand to the overlying soil to reflect the vertical inertial force of the overlying soil. The test results show that the method of mixing steel sand with the soil cover on the structure has little influence on the dynamic characteristics of the soil-structure system and the horizontal relative displacement response of the top and bottom plates of the underground structure under earthquake. Increasing the vertical inertial force of the overlying soil greatly changes the distribution of contact pressure between the surrounding rock and soil mass and the underground structure, thus changing the internal force state of each structural member and increasing the axial compression ratio of the key vertical bearing columns in the frame structure. Increasing the vertical inertia force of the overlying soil results in the stress on the frame of the underground structure and the increased axial compression ratio of the central column, which makes the underground frame structure more prone to earthquake damage. 展开更多
关键词 CENTRIFUGE SHAKING table model test VERTICAL inertial force of overlying SOIL Shallow buried UNDERGROUND frame structure Earthquake damage RESPONSE
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Investigation of the Effects of Baffles on the Shallow Water Sloshing in A Rectangular Tank Using A 2D Turbulent ISPH Method 预览
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作者 Rahim SHAMSODDINI Bahador ABOLPUR 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第1期94-102,共9页
Liquid sloshing is a common phenomenon in the liquid tanks transportation.Liquid waves lead to fluctuating forces on the tank wall.Uncontrolled fluctuations lead to large forces and momentums.Baffles can control these... Liquid sloshing is a common phenomenon in the liquid tanks transportation.Liquid waves lead to fluctuating forces on the tank wall.Uncontrolled fluctuations lead to large forces and momentums.Baffles can control these fluctuations.A numerical method,which has been widely used to model this phenomenon,is Smoothed Particle Hydrodynamics(SPH).The Lagrangian nature of this method makes it suitable for simulating free surface flows.In the present study,an accurate Incompressible Smoothed Particle Hydrodynamics(ISPH)method is developed and improved using the kernel gradient correction tensors,particle shifting algorithms,k–εturbulence model,and free surface particle detectors.Comparisons with the experimental data approve the ability of the present algorithm for simulating shallow water sloshing.The main aim of this study is to investigate the effects of the vertical baffle on the damping of liquid sloshing.Results show that baffles number has a major role in sloshing fluctuation damping. 展开更多
关键词 SPH k–ε VERTICAL BAFFLE SHALLOW water SLOSHING free surface
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青光眼小梁切除术后极度浅前房的白内障手术
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作者 杜珊珊 张凤妍 刘旭辉 《中华眼外伤职业眼病杂志》 2019年第2期96-100,共5页
目的探讨青光眼小梁切除术后极度浅前房的白内障手术的效果。方法回顾性分析2017年1月至2018年3月收治青光眼小梁切除术后极度浅前房白内障5例(5眼)的临床资料。患眼滤过泡扁平或呈囊状,虹膜前后粘连,前房消失,晶状体完全白色浑浊,眼压... 目的探讨青光眼小梁切除术后极度浅前房的白内障手术的效果。方法回顾性分析2017年1月至2018年3月收治青光眼小梁切除术后极度浅前房白内障5例(5眼)的临床资料。患眼滤过泡扁平或呈囊状,虹膜前后粘连,前房消失,晶状体完全白色浑浊,眼压高。均行睫状体平坦部玻璃体穿刺放液联合前房角分离术及晶状体超声乳化人工晶状体植入术:术后随访6?12个月。结果5例术中均顺利形成前房。术前最佳矫正视力为光感或手动,术后为0.2?0.4。术前平均眼压为(38. 80 ± 11.44)mnHg( 1 mmHg =0. 133 kPa),术后眼压明显降低,末次随访平均眼压为(15. 80 ±2.02)mmHg,与术前眼压相比差异有统计学意义(P<0.01)。术后前房明显加深,末次随访中央前房深度平均为(2.81 ±0.21 )mm,与术前相比差异有统计学意义(P <0.001 )。术后6个月,中央角膜内皮细胞平均丢失率为18.4%。术中术后均无严重并发症发生。结论青光眼小梁切除术后极度浅前房白内障可以通过此联合手术解除瞳孔阻滞,加深前房,降低眼斥. 展开更多
关键词 白内障 前房 极度 青光眼 穿刺 玻璃体
The dynamics of low-frequency signal acoustic intensity vector vortex structure in shallow sea
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作者 V.A.Shchurov 《声学学报:英文版》 CSCD 2019年第2期113-131,共19页
Spatiotemporal vector and phase properties of interference field of low-frequency signalling tone between three local vortices in a real shallow sea wave-guide have been studied.It has been demonstrated that in the fi... Spatiotemporal vector and phase properties of interference field of low-frequency signalling tone between three local vortices in a real shallow sea wave-guide have been studied.It has been demonstrated that in the field of constructive interference,components of particle velocity field and acoustic pressure are coherent.As a consequence the transfer of signal energy alog the axis of a shallow sea wave-guide is accomplished with plane wave.Physical objects are detected in the field of destructive interference,which,according to known deterministic signs,can be defined as local vortices of the intensity vector.A large-scale vorticity with acoustic intensity vector curl,components different from zero originates in the vicinity of local vortices.Regular particle displacements of local vortices have been detected against combined receiving device phase centre along the axis of a wave-guide.It has been demonstrated that the structure of vortices depends on signal/noise ratio.Local vortices and vorticity form vortex structure of vector acoustic field.Signalling tone with frequency of 88 ± 1 Hz from near-surface moving sound source was taken into consideration.Introduced results of full-scale experiment expand our concepts of real fundamental properties of shallow sea acoustic field and are to be considered in theoretical models. 展开更多
关键词 Re The DYNAMICS of LOW-FREQUENCY signal acoustic intensity VECTOR VORTEX structure in SHALLOW SEA
Nonlinear Vibration Analyses of Cylindrical Shells Composed of Hyperelastic Materials
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作者 Jing Zhang Jie Xu +3 位作者 Xuegang Yuan Hu Ding Datian Niu Wenzheng Zhang 《固体力学学报:英文版》 SCIE EI CSCD 2019年第4期463-482,共20页
The nonlinear vibration problem is studied for a thin-walled rubber cylindrical shell composed of the classical incompressible Mooney-Rivlin material and subjected to a radial harmonic excitation. With the KirchhofF-L... The nonlinear vibration problem is studied for a thin-walled rubber cylindrical shell composed of the classical incompressible Mooney-Rivlin material and subjected to a radial harmonic excitation. With the KirchhofF-Love hypothesis, DonnelFs nonlinear shallow shell theory, hyperelastic constitutive relation, Lagrange equations and small strain hypothesis, a system of nonlinear differential equations describing the large-deflection vibration of the shell is derived. First, the natural frequencies of radial, circumferential and axial vibrations axe studied. Then, based on the bifurcation diagrams and the Poincare sections, the nonlinear behaviors describing the radial vibration of the shell are illustrated. Examining the influences of structural and material parameters on radial vibration of the shell shows that the vibration modes are highly sensitive to the thickness-radius ratio when the ratio is less than a certain critical value. Moreover, in terms of the results of multimodal expansion, it is found that the response of the shell to radial motion is more regular than that without considering the coupling between modes, while there are more phenomena for the uncoupled case. 展开更多
关键词 THIN-WALLED CYLINDRICAL SHELL INCOMPRESSIBLE Mooney-Rivlin material Donnell5s NONLINEAR SHALLOW SHELL theory NONLINEAR vibration
Characteristics of shallow geothermal fields in major cities of Tibet Autonomous Region 预览
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作者 YANG Hai-jun DONG Jian-xing +1 位作者 SUN Dong HUANG Rui 《地下水科学与工程:英文版》 2019年第1期77-85,共9页
Based on the project titled “Investigation and evaluation of shallow geothermal energy in major cities of Tibet Autonomous Region”, the distribution characteristics and occurrence conditions of shallow geothermal fi... Based on the project titled “Investigation and evaluation of shallow geothermal energy in major cities of Tibet Autonomous Region”, the distribution characteristics and occurrence conditions of shallow geothermal fields in these cities were introduced in this paper. To this end, relevant data in Lhasa, Shigatse and Nyingchi Cities through vertical thermometry was a focus, so as to analyze groundwater temperature and the distribution law of strata with constant temperature. Then through comprehensive comparisons and analysis of the relationship between groundwater temperature and climate, differences in this aspect of Nagqu City were taken as a typical case to clarify formation of geothermal field and corresponding influence on groundwater temperature, furthermore providing basic data for rational development and utilization of shallow geothermal energy in Tibet Autonomous Region. 展开更多
关键词 SHALLOW GEOTHERMAL field GROUNDWATER TEMPERATURE Climate Vertical thermometry STRATUM of constant TEMPERATURE
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MIMO Underwater Acoustic Communication in Shallow Water with Ice Cover 预览
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作者 HAN Xiao YIN Jing-wei +1 位作者 LIU Bing GUO Long-xiang 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第2期237-244,共8页
Although multiple-input multiple-output (MIMO) underwater acoustic (UWA) communication has been intensively investigated in the past years, existing works mainly focus on open-water environment. There is no work repor... Although multiple-input multiple-output (MIMO) underwater acoustic (UWA) communication has been intensively investigated in the past years, existing works mainly focus on open-water environment. There is no work reporting MIMO acoustic communication in under-ice environment. This paper presents results from a recent MIMO acoustic communication experiment which was conducted in Bohai Gulf during winter. In this experiment, high frequency MIMO signals centered at 10 kHz were transmitted from a two-element source array to a four-element vertical receiving array at 1 km range. According to the received signal of different array elements, MIMO acoustic communication in under-ice environment suffers less effect from co-channel interference compared with that in open-water environment. In this paper, time reversal followed by a single channel decision feedback equalizer is used to process the experimental data. It is demonstrated that this simple receiver is capable of realizing robust performance using fewer hydrophones (i.e. 2) without the explicit use of complex co-channel interference cancelation algorithms, such as parallel interference cancelation or serial interference cancelation. 展开更多
关键词 UNDERWATER ACOUSTIC communication MIMO SHALLOW water ICE COVER
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