In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural a...In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.展开更多
The smart home platform integrates with Internet of Things(IoT)devices,smartphones,and cloud servers,enabling seamless and convenient services.It gathers and manages extensive user data,including personal information,...The smart home platform integrates with Internet of Things(IoT)devices,smartphones,and cloud servers,enabling seamless and convenient services.It gathers and manages extensive user data,including personal information,device operations,and patterns of user behavior.Such data plays an essential role in criminal inves-tigations,highlighting the growing importance of specialized smart home forensics.Given the rapid advancement in smart home software and hardware technologies,many companies are introducing new devices and services that expand the market.Consequently,scalable and platform-specific forensic research is necessary to support efficient digital investigations across diverse smart home ecosystems.This study thoroughly examines the core components and structures of smart homes,proposing a generalized architecture that represents various operational environments.A three-stage smart home forensics framework is introduced:(1)analyzing application functions to infer relevant data,(2)extracting and processing data from interconnected devices,and(3)identifying data valuable for investigative purposes.The framework’s applicability is validated using testbeds from Samsung SmartThings and Xiaomi Mi Home platforms,offering practical insights for real-world forensic applications.The results demonstrate that the proposed forensic framework effectively acquires and classifies relevant digital evidence in smart home platforms,confirming its practical applicability in smart home forensic investigations.展开更多
Due to the invisibility and complexity of the underground spaces,monitoring the propagation and filling characteristics of the grouting slurry post the water–sand mixture inrush in metal mines is challenging,which co...Due to the invisibility and complexity of the underground spaces,monitoring the propagation and filling characteristics of the grouting slurry post the water–sand mixture inrush in metal mines is challenging,which complicates engineering treatment.This research investigated the propagation law of cement-sodium silicate slurry under flowing water conditions within the caving mass of a metal mine.First,based on borehole packer test results and borehole TV images,the fractured strata before grouting were classified into four types:cavity,hidden,fissure,and complete.Second,an orthogonal experimental design was employed to evaluate the impact of four key factors—stratigraphic fragmentation,water flow rate,grouting flow rate,and water-cement ratio—on the efficacy of grouting within a caving mass at the site.The results indicate that the factors influencing grouting efficacy are ranked in the following order of importance:stratigraphic fragmentation>water flow rate>water–cement ratio>grouting flow rate.Ultimately,five propagation filling modes—pure slurry,big crack,small crack,small karst pore,and pore penetration—were identified by examining the propagation filling characteristics of slurry in rock samples,incorporating microscopic material structure analysis through scanning electron microscopy and energy spectrum analysis.The findings of this study provide valuable insights into selecting engineering treatment parameters and methodologies,serving as a reference for preventing and controlling water–sand mixture inrush in metal mines,thereby enhancing treatment efficacy and ensuring grouting success.展开更多
The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there...The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there can exist such an interaction via the ultra-long Rossby waves.展开更多
The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity ...The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity and topography of the seabed were measured based on a system composed of plane positioning equipment and an ADV.Experimental results indicate that the development of the scour hole was fast at the beginning, but then the scour rate decreased until reaching equilibrium. Erosion would occur around each pile of the foundation. In most cases, the scour pits were connected in pairs and the outside widths of the scour holes were larger than the inner widths. The maximum scour depth occurred at the side pile of the foundation for each test. In addition, a preliminary investigation shows that the larger the flow velocity, the larger the scour hole dimensions but the shorter equilibrium time. The field maximum scour depth around the foundation was obtained based on the physical experiments with the geometric length scales of 1:27.0, 1:42.5 and 1:68.0, and it agrees with the scour depth estimated by the HEC-18 equation.展开更多
In this work, a mathematical model is established to describe the axial variation of the characteristic flow parameters (particle velocity, solid holdup and pressure gradient) in a downer. An empirical correlation is ...In this work, a mathematical model is established to describe the axial variation of the characteristic flow parameters (particle velocity, solid holdup and pressure gradient) in a downer. An empirical correlation is developed to estimate the particle velocity at the constant velocity section. Experimental investigations are made to validate the downer model. The model simulations have a good agreement with experimental data. Moreover, a formula is derived to predict the first acceleration section length and the whole acceleration section length.展开更多
A water mass in the sea area under investigation is defined as a fuzzy subset in the discourse universe. Possible forms of membership function of water masses in the mixing modified process are discussed with the mixi...A water mass in the sea area under investigation is defined as a fuzzy subset in the discourse universe. Possible forms of membership function of water masses in the mixing modified process are discussed with the mixing theory for conservative concentration of sea water. It may provide bases for making membership functions. Results in this paper may be extended and applied to shallow water. Examples and discussion are given in this paper.展开更多
The importance of the study of saline/fresh water incursion cannot be over-emphasized. Borehole sampling has been extensively used, but it is intrusive, quite expensive and time consuming. Electrical resistivity and e...The importance of the study of saline/fresh water incursion cannot be over-emphasized. Borehole sampling has been extensively used, but it is intrusive, quite expensive and time consuming. Electrical resistivity and electromagnetic techniques have proved successful in groundwater studies since geologic formation properties like porosity and permeability can be correlated with electrical conductivity signatures. Non-intrusive surface geophysical mapping comprising electrical resistivity and electromagnetic methods has been employed to investigate freshwater intrusion and delineate the fresh-saline water interface at the inter-tidal area of Abergwygregyn, North Wales, United Kingdom. Frequency Domain Electromagnetic Profiling and Constant Separation Traversing were used to produce 2-D images and contour plots enabling the identification of freshwater plumes onshore and in the central parts of the study area. Ground truth methods comprised chemical analyses and detailed, point specific information on the stratigraphy. The freshwater intruding from the coastal area appears to be pushing the saline-water further offshore due to the high piezometric head caused by the mountains and hills of Snowdonia adjacent to the study area. The fresh/saline water interface correlates quite well with previous studies carried out in the area. On the basis of the results of the resistivity and conductivity geophysical investigations the freshwater plumes and fresh/saline water interface in the study area were effectively identified and delineated.展开更多
Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as hand...Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as handle,thickness, tensile strength , stiffness and air permeability after the water treatment were investigated.展开更多
For evaluate the aerodynamic character of the turbine cascades which have the aft-loaded profile, the experimental investigation was carried out on the low speed annular wind tunnel. And the detailed measurements of t...For evaluate the aerodynamic character of the turbine cascades which have the aft-loaded profile, the experimental investigation was carried out on the low speed annular wind tunnel. And the detailed measurements of the aerodynamic parameters were made from upstream to downstream of the two type turbine cascades, the one is the conventional straight blades cascade, the other is the curved blades cascades. The static pressure distributions on the endwall and the blade surface were also carried out. The influence of the aft-loaded profile and the curved blade on the development of loss and the pressure distribution was discussed, and analyses the different flow phenomena and mechanism in two type turbine cascades.展开更多
In this paper we use a 10-layer radiation transfer model to systematically investigate the relation between brightness temperature and the rainfall rates at 37 GHz, including various viewing of microwave (MW) remote s...In this paper we use a 10-layer radiation transfer model to systematically investigate the relation between brightness temperature and the rainfall rates at 37 GHz, including various viewing of microwave (MW) remote sensing and different surface condition, with main focus on the influence of the structure of ice-phase layer. The results show that the quantitative rainfall measurement can not be reliably obtained over the land from spuceborne radiometer at this wavelength and the structures of ice layer are very important in determining the 'observed' brightness temperature for the spaceborne MW remote sensing.展开更多
This study investigates the horizontal load-bearing behavior of the Caisson-type Diaphragm Wall with Variable Cross-sections(CDWVC),a novel foundation system that integrates closed and open wall segments to improve pe...This study investigates the horizontal load-bearing behavior of the Caisson-type Diaphragm Wall with Variable Cross-sections(CDWVC),a novel foundation system that integrates closed and open wall segments to improve performance and material efficiency.A series of 1g model tests was conducted using instrumented plexiglass models under controlled soil conditions to evaluate the bearing behavior under lateral loading.Finite difference simulations were also performed to complement the experimental findings and provide additional insights.The performance of CDWVCs with varying closed segment heights and open segment widths was analyzed.Results indicate that taller closed segments reduce horizontal displacements under equivalent loads and shift the rotation point closer to the surface,thereby improving overall stability.While increasing the height of the closed wall segment leads to modest improvements in horizontal ultimate bearing capacity,these gains are often outweighed by significant increases in material consumption.Conversely,expanding the width of the open wall segment results in a more substantial increase in horizontal ultimate bearing capacity relative to material usage,improving load transfer and overall stability.This design strategy achieves a favorable balance between load capacity and material efficiency compared to increasing closed wall height.The findings underscore the importance of design choices in the performance of CDWVCs under horizontal loading conditions.展开更多
Forensic imaging is a non-invasive examination process during the forensic investigation.It is mainly used in forensic pathology as an adjunct to the traditional autopsy.In the past two decades,forensic imaging has be...Forensic imaging is a non-invasive examination process during the forensic investigation.It is mainly used in forensic pathology as an adjunct to the traditional autopsy.In the past two decades,forensic imaging has been vigorously developed by forensic experts from computed tomography(CT)to multiple augmented techniques through CT and magnetic resonance imaging(MRI).The application field of forensic imaging has also been broadened as its advantages are recognised by more forensic practitioners.In addition to the forensic pathology,this technique has been used in other forensic disciplines,including forensic anthropology,forensic odontology,forensic ballistics and wildlife forensics,etc.This article reviews the development of forensic imaging as the practice and research development in different forensic disciplines based on the relevant literature analysis.展开更多
Rock-quality designation(RQD) plays a significant role in rock mass analysis and is an important parameter in geotechnical and geological engineering.However,the RQD variation with scanline length has not yet been com...Rock-quality designation(RQD) plays a significant role in rock mass analysis and is an important parameter in geotechnical and geological engineering.However,the RQD variation with scanline length has not yet been comprehensively considered in RQD.In this study,three-dimensional fracture network modeling was used to simulate actual rock mass,and numerous scanlines were set in the fracture network for investigation on RQD variation.Models and equations(i.e.,models A-A,N-N,and A-A-S,as well as the Priest-Hudson and Sen-Kazi equations) were summarized for the study.A corrected equation was proposed to eliminate the errors from using the Priest-Hudson and Sen-Kazi equations.In addition,inhomogeneous and anisotropic features were investigated,and the optimal thresholds for RQD calculation were determined,which varied with the study orientation and rock mass feature.When the inhomogeneity was studied in the x direction,the optimal threshold was found to be 4 m.When anisotropy was studied,the optimal threshold was found to be 3 m.展开更多
Accurate variable speed characteristics are needed for water source heat pumps （WSHP） to de- sign variable speed controls to adjust refrigerant flow rates in heat pumps and air conditioners. The system capacity can ...Accurate variable speed characteristics are needed for water source heat pumps （WSHP） to de- sign variable speed controls to adjust refrigerant flow rates in heat pumps and air conditioners. The system capacity can then be regulated to match the compressor loads to the heating or cooling needs to improve the energy efficiency and lower energy costs. The motor and compression characteristics of WSHP were modeled to include the coupling between the motor speed and the torque characteristics and compression characteristics. An analytical model is given for a variable speed hermetic scroll compressor that describes various factors, such as the drive frequency, suction pressure, and discharge pressure as a function of the compressor speed. The model was validated experimentally using R22 and R134a in an experimental WSHP with variable speed control using frequency conversion. The results show that the analytical model properly describes the variable speed characteristics and provides a control strategy for adjusting the ca- pacity of scroll compressors to match the heat pump or air conditioner operating conditions.展开更多
This paper presents a 2-D numerical investigation on interaction between regular waves and a fully submerged horizontal cylinder.A mathematical model of numerical wave tank with two-way fluid-solid interactions were d...This paper presents a 2-D numerical investigation on interaction between regular waves and a fully submerged horizontal cylinder.A mathematical model of numerical wave tank with two-way fluid-solid interactions were developed and validated.The wave-induced vibrations of a single-degree-of-freedom cylinder were simulated at eleven gap ratios(d/a=8,10,12,14,16,18,20,22,24,28 and 32).Numerical results indicate that significant nonlinear characteristics are introduced into the originally linear waves with the presence of cylinder.Based on the variation characteristics of cylinder vibration amplitude,the gap ratios can be divided into three ranges,i.e.,the uncertain range(8≤d/a≤14),quasi-linear range(14≤d/a≤20)and linear range(20≤d/a≤32).Under the same wave condition,the gap ratio does not affect the frequencies of vortex shedding and cylinder vibration.The presence of the cylinder complicates the flow field and suppress the vortex shedding around the cylinder.展开更多
The wind environment around tall buildings in a central business district(CBD)was numerically investigated.The district covers an area of-^4.0 km2 and features a high density of tall buildings.In this study,only build...The wind environment around tall buildings in a central business district(CBD)was numerically investigated.The district covers an area of-^4.0 km2 and features a high density of tall buildings.In this study,only buildings taller than 20 m were considered,resulting in 173 tall buildings in the analysis.The numerical investigation was realized using the commercial computational fluid dynamics code FLUENT with the realizable A-6:turbulence model.Special efforts were made to maintain inflow boundary conditions throughout the computational domain.The reliability of the numerical method was validated using results from an experimental investigation conducted in the core area of the CBD(〜1.5 km2).Experimental and numerical investigations of wind speed ratios at the center of the three tallest buildings in the CBD agree within an uncertainty factor of 2.0.Both the experimental and numerical results show that wind speed ratios in the wind field with exposure category D are higher than those from the wind field with exposure category B.Based on the above validation work,the wind environment around tall buildings in the whole CBD was then investigated by numerical simulation.Common flow phenomena and patterns,such as stagnation points,shielding effects,separation flow,and channeling flow,were identified around the tall buildings.The pedestrianlevel wind environment around tall buildings in the CBD was further evaluated using nearby meteorological wind data.The evaluation results show that some pedestrian activities,such as sitting at the center of the three tallest buildings,are unadvisable when the wind blows from the south-east.展开更多
Medical research,including clinical trials,observational studies,and studies on medicine-related translational and basic sciences,is extremely important for the development and improvement of clinical medical care.How...Medical research,including clinical trials,observational studies,and studies on medicine-related translational and basic sciences,is extremely important for the development and improvement of clinical medical care.However,many physicians in China may not have received systematic and comprehensive education or training for medical research since in most medical universities or colleges/schools,methodology for clinical research(design,planning,conducting,analyses,and reporting)has not been included in their curricula.Therefore,many clinicians need to learn on their own and very few of them might attend limited short training courses for clinical studies.展开更多
The heteronuclear organometallic complexes with metal-to-metal bond may act as some model compounds in the investigation of catalytic mechanisms or may potentially be catalytically active, and therefore they attract m...The heteronuclear organometallic complexes with metal-to-metal bond may act as some model compounds in the investigation of catalytic mechanisms or may potentially be catalytically active, and therefore they attract much attention to their research. There were not very many reports about organometallic complexes with metal-to-rare展开更多
The electronic transport properties of amorphous alloys have been extensively investigated. Previous investigations showed that the resistivity of amorphous alloys is generally very high. Its temperature coefficient i...The electronic transport properties of amorphous alloys have been extensively investigated. Previous investigations showed that the resistivity of amorphous alloys is generally very high. Its temperature coefficient is remarkably small. The resistivity minimum phenomenon not only may appear in dilute alloy of magnetic impttries, but also can coexist with ferromagnetism. In amorphous alloys, although several theoretical models have been proposed, explanation of the resistivity anomalies has been a subject of controversy.展开更多
基金supported by the CAS Strategic Priority Research Program(No.XDB0760102),the Ministry of Science and Technology of China(No.2022YFF0802501)the Major Science and Technology Infrastructure Maintenance and Transformation Project of the Chinese Academy of Sciences,Shanghai Science and Technology Innovation Action Plan-Phospherus Project(No.23YF1426200)the National Key Research and Development Program of China(No.2024YFE0212200).
文摘In winter 2018,an aerosol physicochemical experiment was conducted in the Western Pacific Ocean(WPO)aboard the Research Vessel KEXUE of Chinese Academy of Sciences.This study systematically investigated both natural and anthropogenic effects on marine aerosols optical properties,as well as the applicability of multi-satellite products and IMPROVE equation.The averaged aerosol optical depth(AOD500 nm)was 0.31±0.16 andÅngström exponent440–675 nm was 0.29±0.30.In offshore China,significant anthropogenic emissions affected the marine environment.In remote WPO,dust aerosols transported from northern China,Siberia,Central Asia,and those settling from the upper troposphere originating from north Africa,Arabian peninsula,and western India,were dominant.The spatial trends of AOD were opposite in the mid-latitude and southern seas of WPO.The highest AOD,0.32±0.23,appeared along the coast of South Asia at mid-latitude,decreasing from offshore seas to remote oceans.In low-latitude and equatorial seas,AOD significantly increased from coast to remote oceans.Ångström exponent dropped significantly from the coast to remote oceans as anthropogenic influence diminished across the entire WPO.Correlation analysis showed that both MODIS-C6 and Himawari AOD prod-ucts showed similar applicability in coastal urban areas,while Himawari AOD is highly recommended for coastal background and marine environment due to its finer resolution.The extinction coefficient derived from PM_(2.5) chemical compositions using IMPROVE algorithm exhibited a significant correlation(R^(2)=0.58)with the con-currently measured AOD in the absence of long-distance transport,suggesting that the IMPROVE is a reasonable proxy of the columnar average of marine aerosol extinctions free from transport influences.
文摘The smart home platform integrates with Internet of Things(IoT)devices,smartphones,and cloud servers,enabling seamless and convenient services.It gathers and manages extensive user data,including personal information,device operations,and patterns of user behavior.Such data plays an essential role in criminal inves-tigations,highlighting the growing importance of specialized smart home forensics.Given the rapid advancement in smart home software and hardware technologies,many companies are introducing new devices and services that expand the market.Consequently,scalable and platform-specific forensic research is necessary to support efficient digital investigations across diverse smart home ecosystems.This study thoroughly examines the core components and structures of smart homes,proposing a generalized architecture that represents various operational environments.A three-stage smart home forensics framework is introduced:(1)analyzing application functions to infer relevant data,(2)extracting and processing data from interconnected devices,and(3)identifying data valuable for investigative purposes.The framework’s applicability is validated using testbeds from Samsung SmartThings and Xiaomi Mi Home platforms,offering practical insights for real-world forensic applications.The results demonstrate that the proposed forensic framework effectively acquires and classifies relevant digital evidence in smart home platforms,confirming its practical applicability in smart home forensic investigations.
基金The National Natural Science Foundation of China,Grant/Award Number:42130706。
文摘Due to the invisibility and complexity of the underground spaces,monitoring the propagation and filling characteristics of the grouting slurry post the water–sand mixture inrush in metal mines is challenging,which complicates engineering treatment.This research investigated the propagation law of cement-sodium silicate slurry under flowing water conditions within the caving mass of a metal mine.First,based on borehole packer test results and borehole TV images,the fractured strata before grouting were classified into four types:cavity,hidden,fissure,and complete.Second,an orthogonal experimental design was employed to evaluate the impact of four key factors—stratigraphic fragmentation,water flow rate,grouting flow rate,and water-cement ratio—on the efficacy of grouting within a caving mass at the site.The results indicate that the factors influencing grouting efficacy are ranked in the following order of importance:stratigraphic fragmentation>water flow rate>water–cement ratio>grouting flow rate.Ultimately,five propagation filling modes—pure slurry,big crack,small crack,small karst pore,and pore penetration—were identified by examining the propagation filling characteristics of slurry in rock samples,incorporating microscopic material structure analysis through scanning electron microscopy and energy spectrum analysis.The findings of this study provide valuable insights into selecting engineering treatment parameters and methodologies,serving as a reference for preventing and controlling water–sand mixture inrush in metal mines,thereby enhancing treatment efficacy and ensuring grouting success.
文摘The question of possible teleconnections between the middle latitude general circulation and the Indian south-west monsoon was investigated in this paper. Within the framework of a simple model it was shown that there can exist such an interaction via the ultra-long Rossby waves.
基金financially supported by the National Key Research and Development Program of China(Grant No.2017YFC1404200)the Tianjin Key Program of Applied Foundation and Advanced-Tech Research,China(Grant No.18JCZDJC40200)+1 种基金the National High Technology Research and Development Program of China(863 Program,Grant No.2012AA051709)the National Natural Science Foundation of China(Grant No.51509183)
文摘The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity and topography of the seabed were measured based on a system composed of plane positioning equipment and an ADV.Experimental results indicate that the development of the scour hole was fast at the beginning, but then the scour rate decreased until reaching equilibrium. Erosion would occur around each pile of the foundation. In most cases, the scour pits were connected in pairs and the outside widths of the scour holes were larger than the inner widths. The maximum scour depth occurred at the side pile of the foundation for each test. In addition, a preliminary investigation shows that the larger the flow velocity, the larger the scour hole dimensions but the shorter equilibrium time. The field maximum scour depth around the foundation was obtained based on the physical experiments with the geometric length scales of 1:27.0, 1:42.5 and 1:68.0, and it agrees with the scour depth estimated by the HEC-18 equation.
基金the National Program of Basic Research (No. G1999022103) the National Natural Science Foundation of China (No. 29936090).
文摘In this work, a mathematical model is established to describe the axial variation of the characteristic flow parameters (particle velocity, solid holdup and pressure gradient) in a downer. An empirical correlation is developed to estimate the particle velocity at the constant velocity section. Experimental investigations are made to validate the downer model. The model simulations have a good agreement with experimental data. Moreover, a formula is derived to predict the first acceleration section length and the whole acceleration section length.
文摘A water mass in the sea area under investigation is defined as a fuzzy subset in the discourse universe. Possible forms of membership function of water masses in the mixing modified process are discussed with the mixing theory for conservative concentration of sea water. It may provide bases for making membership functions. Results in this paper may be extended and applied to shallow water. Examples and discussion are given in this paper.
文摘The importance of the study of saline/fresh water incursion cannot be over-emphasized. Borehole sampling has been extensively used, but it is intrusive, quite expensive and time consuming. Electrical resistivity and electromagnetic techniques have proved successful in groundwater studies since geologic formation properties like porosity and permeability can be correlated with electrical conductivity signatures. Non-intrusive surface geophysical mapping comprising electrical resistivity and electromagnetic methods has been employed to investigate freshwater intrusion and delineate the fresh-saline water interface at the inter-tidal area of Abergwygregyn, North Wales, United Kingdom. Frequency Domain Electromagnetic Profiling and Constant Separation Traversing were used to produce 2-D images and contour plots enabling the identification of freshwater plumes onshore and in the central parts of the study area. Ground truth methods comprised chemical analyses and detailed, point specific information on the stratigraphy. The freshwater intruding from the coastal area appears to be pushing the saline-water further offshore due to the high piezometric head caused by the mountains and hills of Snowdonia adjacent to the study area. The fresh/saline water interface correlates quite well with previous studies carried out in the area. On the basis of the results of the resistivity and conductivity geophysical investigations the freshwater plumes and fresh/saline water interface in the study area were effectively identified and delineated.
文摘Analytical examination was made to ascertain the effect of the high pressure water flow on the fabric properties.Polyester/cotton blended cambric was spurted by high pressure water flow. Fabric properties such as handle,thickness, tensile strength , stiffness and air permeability after the water treatment were investigated.
文摘For evaluate the aerodynamic character of the turbine cascades which have the aft-loaded profile, the experimental investigation was carried out on the low speed annular wind tunnel. And the detailed measurements of the aerodynamic parameters were made from upstream to downstream of the two type turbine cascades, the one is the conventional straight blades cascade, the other is the curved blades cascades. The static pressure distributions on the endwall and the blade surface were also carried out. The influence of the aft-loaded profile and the curved blade on the development of loss and the pressure distribution was discussed, and analyses the different flow phenomena and mechanism in two type turbine cascades.
基金This project is supported by National Science Foundation of China
文摘In this paper we use a 10-layer radiation transfer model to systematically investigate the relation between brightness temperature and the rainfall rates at 37 GHz, including various viewing of microwave (MW) remote sensing and different surface condition, with main focus on the influence of the structure of ice-phase layer. The results show that the quantitative rainfall measurement can not be reliably obtained over the land from spuceborne radiometer at this wavelength and the structures of ice layer are very important in determining the 'observed' brightness temperature for the spaceborne MW remote sensing.
基金National Nature Science Foundation of China(Grant No.42007247)National Foreign Expert Project(Grant No.DL2023036001L)Sichuan Science and Technology Program(No.2024JDHJ0019).
文摘This study investigates the horizontal load-bearing behavior of the Caisson-type Diaphragm Wall with Variable Cross-sections(CDWVC),a novel foundation system that integrates closed and open wall segments to improve performance and material efficiency.A series of 1g model tests was conducted using instrumented plexiglass models under controlled soil conditions to evaluate the bearing behavior under lateral loading.Finite difference simulations were also performed to complement the experimental findings and provide additional insights.The performance of CDWVCs with varying closed segment heights and open segment widths was analyzed.Results indicate that taller closed segments reduce horizontal displacements under equivalent loads and shift the rotation point closer to the surface,thereby improving overall stability.While increasing the height of the closed wall segment leads to modest improvements in horizontal ultimate bearing capacity,these gains are often outweighed by significant increases in material consumption.Conversely,expanding the width of the open wall segment results in a more substantial increase in horizontal ultimate bearing capacity relative to material usage,improving load transfer and overall stability.This design strategy achieves a favorable balance between load capacity and material efficiency compared to increasing closed wall height.The findings underscore the importance of design choices in the performance of CDWVCs under horizontal loading conditions.
文摘Forensic imaging is a non-invasive examination process during the forensic investigation.It is mainly used in forensic pathology as an adjunct to the traditional autopsy.In the past two decades,forensic imaging has been vigorously developed by forensic experts from computed tomography(CT)to multiple augmented techniques through CT and magnetic resonance imaging(MRI).The application field of forensic imaging has also been broadened as its advantages are recognised by more forensic practitioners.In addition to the forensic pathology,this technique has been used in other forensic disciplines,including forensic anthropology,forensic odontology,forensic ballistics and wildlife forensics,etc.This article reviews the development of forensic imaging as the practice and research development in different forensic disciplines based on the relevant literature analysis.
基金supported by the National Natural Science Foundations of China (Grant Nos. 40872170,40902077 and 41072196)the Doctoral Program Foundation of Higher Education of China (Grant No. 20090061110054)+2 种基金2010 non-profit scientific special research funds of Ministry of Water Resources (Grant No. 201001008)Jilin University's 985 project (Grant No. 450070021107)the Graduate Innovation Fund of Jilin University (Grant No. 20121073)
文摘Rock-quality designation(RQD) plays a significant role in rock mass analysis and is an important parameter in geotechnical and geological engineering.However,the RQD variation with scanline length has not yet been comprehensively considered in RQD.In this study,three-dimensional fracture network modeling was used to simulate actual rock mass,and numerous scanlines were set in the fracture network for investigation on RQD variation.Models and equations(i.e.,models A-A,N-N,and A-A-S,as well as the Priest-Hudson and Sen-Kazi equations) were summarized for the study.A corrected equation was proposed to eliminate the errors from using the Priest-Hudson and Sen-Kazi equations.In addition,inhomogeneous and anisotropic features were investigated,and the optimal thresholds for RQD calculation were determined,which varied with the study orientation and rock mass feature.When the inhomogeneity was studied in the x direction,the optimal threshold was found to be 4 m.When anisotropy was studied,the optimal threshold was found to be 3 m.
基金Supported by the National Natural Science Foundation of China(No. 50576042)
文摘Accurate variable speed characteristics are needed for water source heat pumps （WSHP） to de- sign variable speed controls to adjust refrigerant flow rates in heat pumps and air conditioners. The system capacity can then be regulated to match the compressor loads to the heating or cooling needs to improve the energy efficiency and lower energy costs. The motor and compression characteristics of WSHP were modeled to include the coupling between the motor speed and the torque characteristics and compression characteristics. An analytical model is given for a variable speed hermetic scroll compressor that describes various factors, such as the drive frequency, suction pressure, and discharge pressure as a function of the compressor speed. The model was validated experimentally using R22 and R134a in an experimental WSHP with variable speed control using frequency conversion. The results show that the analytical model properly describes the variable speed characteristics and provides a control strategy for adjusting the ca- pacity of scroll compressors to match the heat pump or air conditioner operating conditions.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFC3202605)supported by the Water Conservancy Science and Technology Project in Jiangsu Province(Grant No.2022061)the 111 Project(Grant No.B17015).
文摘This paper presents a 2-D numerical investigation on interaction between regular waves and a fully submerged horizontal cylinder.A mathematical model of numerical wave tank with two-way fluid-solid interactions were developed and validated.The wave-induced vibrations of a single-degree-of-freedom cylinder were simulated at eleven gap ratios(d/a=8,10,12,14,16,18,20,22,24,28 and 32).Numerical results indicate that significant nonlinear characteristics are introduced into the originally linear waves with the presence of cylinder.Based on the variation characteristics of cylinder vibration amplitude,the gap ratios can be divided into three ranges,i.e.,the uncertain range(8≤d/a≤14),quasi-linear range(14≤d/a≤20)and linear range(20≤d/a≤32).Under the same wave condition,the gap ratio does not affect the frequencies of vortex shedding and cylinder vibration.The presence of the cylinder complicates the flow field and suppress the vortex shedding around the cylinder.
基金This research was supported by the Ministry of Science and Technology of the People’s Republic of China(Grant Nos.2015CB452806 and 2018YFB1501104)the National Natural Science Foundation of China(Grant No.51408196)+1 种基金the Natural Science Foundation of Shanghai(Grant No.19ZR1469200).Further support was provided by the State Key Laboratory for Disaster Reduction in Civil Engineering(No.SLDRCE15-A-04)the Study on the Wind Characteristics Caused by Typhoons Considering Offshore Wind Farm Safety along Fujian Province(No.2016FD(8)-008).The authors are indebted to the anonymous reviewers who provided valuable suggestions that improved the manuscript,particularly scientific aspects.
文摘The wind environment around tall buildings in a central business district(CBD)was numerically investigated.The district covers an area of-^4.0 km2 and features a high density of tall buildings.In this study,only buildings taller than 20 m were considered,resulting in 173 tall buildings in the analysis.The numerical investigation was realized using the commercial computational fluid dynamics code FLUENT with the realizable A-6:turbulence model.Special efforts were made to maintain inflow boundary conditions throughout the computational domain.The reliability of the numerical method was validated using results from an experimental investigation conducted in the core area of the CBD(〜1.5 km2).Experimental and numerical investigations of wind speed ratios at the center of the three tallest buildings in the CBD agree within an uncertainty factor of 2.0.Both the experimental and numerical results show that wind speed ratios in the wind field with exposure category D are higher than those from the wind field with exposure category B.Based on the above validation work,the wind environment around tall buildings in the whole CBD was then investigated by numerical simulation.Common flow phenomena and patterns,such as stagnation points,shielding effects,separation flow,and channeling flow,were identified around the tall buildings.The pedestrianlevel wind environment around tall buildings in the CBD was further evaluated using nearby meteorological wind data.The evaluation results show that some pedestrian activities,such as sitting at the center of the three tallest buildings,are unadvisable when the wind blows from the south-east.
文摘Medical research,including clinical trials,observational studies,and studies on medicine-related translational and basic sciences,is extremely important for the development and improvement of clinical medical care.However,many physicians in China may not have received systematic and comprehensive education or training for medical research since in most medical universities or colleges/schools,methodology for clinical research(design,planning,conducting,analyses,and reporting)has not been included in their curricula.Therefore,many clinicians need to learn on their own and very few of them might attend limited short training courses for clinical studies.
基金Project supported by the Science Fund of the Chinese Academy of Sciences
文摘The heteronuclear organometallic complexes with metal-to-metal bond may act as some model compounds in the investigation of catalytic mechanisms or may potentially be catalytically active, and therefore they attract much attention to their research. There were not very many reports about organometallic complexes with metal-to-rare
文摘The electronic transport properties of amorphous alloys have been extensively investigated. Previous investigations showed that the resistivity of amorphous alloys is generally very high. Its temperature coefficient is remarkably small. The resistivity minimum phenomenon not only may appear in dilute alloy of magnetic impttries, but also can coexist with ferromagnetism. In amorphous alloys, although several theoretical models have been proposed, explanation of the resistivity anomalies has been a subject of controversy.
