With the acceleration of urbanization and the improvement of people’s living standards,people have increasingly higher requirements for the living environment,especially in the design of outdoor balconies.However,exi...With the acceleration of urbanization and the improvement of people’s living standards,people have increasingly higher requirements for the living environment,especially in the design of outdoor balconies.However,existing landscape balconies generally suffer from insufficient shading and rainwater drainage problems,which affects people’s living experience.In response to this problem,this article proposes a new design scheme for building landscape balconies to solve the existing problems of landscape balconies.This design plan fully considers the user’s usage needs and scenarios,improves the use value and comfort of the balcony through technical means,and achieves intelligence and functionality.展开更多
A centrifuge modeling test and a three-dimensional finite element analysis(FEA)of super-long rock-socketed bored pile groups of the Tianxingzhou Bridge are proposed.Based on the similarity theory,different prototypi...A centrifuge modeling test and a three-dimensional finite element analysis(FEA)of super-long rock-socketed bored pile groups of the Tianxingzhou Bridge are proposed.Based on the similarity theory,different prototypical materials are simulated using different indicators in the centrifuge model.The silver sand,the shaft and the pile cap are simulated according to the natural density,the compressive stiffness and the bending stiffness,respectively.The finite element method(FEM)is implemented and analyzed in ANSYS,in which the stress field during the undisturbed soil stage,the boring stage,the concrete-casting stage and the curing stage are discussed in detail.Comparisons in terms of load-settlement,shaft axial force distribution and lateral friction between the numerical results and the test data are carried out to investigate the bearing behaviors of super-long rock-socketed bored pile groups under loading and unloading conditions.Results show that there is a good agreement between the centrifuge modeling tests and the FEM.In addition,the load distribution at the pile top is complicated,which is related to the stiffness of the cap,the corresponding assumptions and the analysis method.The shaft axial force first increases slightly with depth then decreases sharply,and the rate of decrease in rock is greater than that in sand and soil.展开更多
Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K^(+),but the basic storage mechanism is still unclear.Herein,we co...Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K^(+),but the basic storage mechanism is still unclear.Herein,we construct and optimize 3D honeycomb-like carbon grafted with plentiful COOH/C=O functional groups(OFGC)as anodes for potassium ion batteries.The OFGC electrode with steady structure and rich functional groups can effectively contribute to the capacity enhancement and the formation of stable solid electrolyte interphase(SEI)film,achieving a high reversible capacity of 230 mAh g^(-1) at 3000 mA g^(-1) after 10,000 cycles(almost no capacity decay)and an ultra-long cycle time over 18 months at 100 mA g^(-1).The study results revealed the reversible storage mechanism between K^(+)and COOH/C=O functional groups by forming C-O-K compounds.Meanwhile,the in situ electrochemical impedance spectroscopy proved the highly reversible and rapid de/intercalation kinetics of K+in the OFGC electrode,and the growth process of SEI films.In particular,the full cells assembled by Prussian blue cathode exhibit a high energy density of 113 Wh kg^(-1) after 800 cycles(calculated by the total mass of anode and cathode),and get the light-emitting diodes lamp and ear thermometer running.展开更多
In order to find out the bearing behavior of super-long piles located in deep soft clay over stiff layers around Dongting Lake, China, a test pile was first designed with the field loading test finished afterward. Bas...In order to find out the bearing behavior of super-long piles located in deep soft clay over stiff layers around Dongting Lake, China, a test pile was first designed with the field loading test finished afterward. Based on the measured test results, load transfer mechanism and bearing behavior of the pile shaft were discussed in detail. Then, by introducing a bi-linear model for shaft friction and the tri-linear model for pile tip resistance, respectively, the governing differential equation of pile soil system was set up by the load transfer method with the analytical solutions derived as well, taking into account the effect by stratified feature and various bearing conditions of subsoil, material nonlinearity, and the sediment under pile tip. Furthermore, formulas to determine the axial capacity of super-long piles by the pile top settlement were advised and applied to analyze the test pile. Good agreement between the predicted load settlement variations and the measured data is obtained to verify the validity of the present method. The results also show that, the axial bearing capacity of super-long piles should be controlled by the allowable pile top settlement, and buckling stability of the pile shaft should be paid attention as well.展开更多
Nanowire(NW) structures is an alternative candidate for constructing the next generation photoelectrochemical water splitting system, due to the outstanding optical and electrical properties. NW photoelectrodes compar...Nanowire(NW) structures is an alternative candidate for constructing the next generation photoelectrochemical water splitting system, due to the outstanding optical and electrical properties. NW photoelectrodes comparing to traditional semiconductor photoelectrodes shows the comparatively shorter transfer distance of photo-induced carriers and the increase amount of the surface reaction sites, which is beneficial for lowering the recombination probability of charge carriers and improving their photoelectrochemical(PEC) performances. Here, we demonstrate for the first time that super-long Cu_2O NWs, more than 4.5 μm,with highly efficient water splitting performance, were synthesized using a cost-effective anodic alumina oxide(AAO) template method. In comparison with the photocathode with planar Cu_2O films, the photocathode with Cu_2O NWs demonstrates a significant enhancement in photocurrent, from –1.00 to –2.75 mA/cm^2 at –0.8 V versus Ag/AgCl. After optimization of the photoelectrochemical electrode through depositing Pt NPs with atomic layer deposition(ALD) technology on the Cu_2O NWs, the plateau of photocurrent has been enlarged to –7 mA/cm^2 with the external quantum yield up to 34% at 410 nm. This study suggests that the photoelectrode based on Cu_2O NWs is a hopeful system for establishing high-efficiency water splitting system under visible light.展开更多
In order to discuss the buckling stability of super-long rock-socketed filling piles widely used in bridge engineering in soft soil area such as Dongting Lake, the second stability type was adopted instead of traditio...In order to discuss the buckling stability of super-long rock-socketed filling piles widely used in bridge engineering in soft soil area such as Dongting Lake, the second stability type was adopted instead of traditional first type, and a newly invented numerical analysis method, i.e. the element-free Galerkin method (EFGM), was introduced to consider the non-concordant deformation and nonlinearity of the pile-soil interface. Then, based on the nonlinear elastic-ideal plastic pile-soil interface model, a nonlinear iterative algorithm was given to analyze the pile-soil interaction, and a program for buckling analysis of piles by the EFGM (PBAP-EFGM) and arc length method was worked out as well. The application results in an engineering example show that, the shape of pile top load-settlement curve obtained by the program agrees well with the measured one, of which the difference may be caused mainly by those uncertain factors such as possible initial defects of pile shaft and the eccentric loading during the test process. However, the calculated critical load is very close with the measured ultimate load of the test pile, and the corresponding relative error is only 5.6%, far better than the calculated values by linear and nonlinear incremental buckling analysis (with a greater relative error of 37.0% and 15.4% respectively), which also verifies the rationality and feasibility of the present method.展开更多
The total length of the second stage of the water supply project in the northern areas of the Xinjiang Uygur Autonomous Region is 540 km, of which the total length of the tunnels is 516 km. The total tun- neling milea...The total length of the second stage of the water supply project in the northern areas of the Xinjiang Uygur Autonomous Region is 540 km, of which the total length of the tunnels is 516 km. The total tun- neling mileage is 569 km, which includes 49 slow-inclined shafts and vertical shafts. Among the tunnels constructed in the project, the Ka-Shuang tunnel, which is a single tunnel with a length of 283 kin, is cur- rently the longest water-conveyance tunnel in the world. The main tunnel of the Ka-Shuang tunnel is divided into 18 tunnel-boring machine (TBM) sections, and 34 drilling-and-blasting sections, with 91 tunnel faces. The construction of the Ka-Shuang tunnel has been regarded as an unprecedented challenge for project construction management, risk control, and safe and efficient construction; it has also pre- sented higher requirements for the design, manufacture, operation, and maintenance of the TBMs and their supporting equipment. Based on the engineering characteristics and adverse geological conditions, it is necessary to analyze the major problems confronted by the construction and systematically locate disaster sources. In addition, the risk level should be reasonably ranked, responsibility should be clearly identified, and a hierarchical-control mechanism should be established. Several techniques are put for- ward in this paper to achieve the objectives mentioned above; these include advanced geological prospecting techniques, intelligent tunneling techniques combined with the sensing and fusion of infor- mation about rock parameters and mechanical parameters, monitoring and early-warning techniques, and modern information technologies. The application of these techniques offers scientific guidance for risk control and puts forward technical ideas about improving the efficiency of safe tunneling. These techniques and ideas have great significance for the development of modern tunneling technolo- gies and research into major construction equipment.展开更多
This paper analyses perturbations of Noether symmetry, Lie symmetry, and form invariance for super-long elastic slender rod systems. Criterion and structure equations of the symmetries after disturbance are proposed. ...This paper analyses perturbations of Noether symmetry, Lie symmetry, and form invariance for super-long elastic slender rod systems. Criterion and structure equations of the symmetries after disturbance are proposed. Considering perturbation of all infinitesimal generators, three types of adiabatic invariants induced by perturbation of symmetries for the system are obtained.展开更多
Electrochemical cyclic voltammetric(CV) scan was applied to inducing the partial oxidation and defects of carbon nanotubes(CNTs).The electrochemically induced functional groups and physical defects were demonstrat...Electrochemical cyclic voltammetric(CV) scan was applied to inducing the partial oxidation and defects of carbon nanotubes(CNTs).The electrochemically induced functional groups and physical defects were demonstrated to show positive effects on the nanotube capacitance,as exemplified by super-long CNT arrays as model for the easy fabrication of CNT electrodes.Specifically,the initial hydrophobic nanotube surface becomes hydrophilic and a ten-time enhancement in capacitance is observed with respect to the pristine CNT sample.Thus,the electrochemical CV pretreatment can be used as an effective approach to activate the CNT surface for an enhanced electrochemical performance in capacitors,and many other advanced devices beyond capacitors,such as electrochemical sensors and batteries.展开更多
DNA is a nucleic acid molecule with double-helical structures that are special symmetrical structures attracting great attention of numerous researchers. The super-long elastic slender rod, an important structural mod...DNA is a nucleic acid molecule with double-helical structures that are special symmetrical structures attracting great attention of numerous researchers. The super-long elastic slender rod, an important structural model of DNA and other long-train molecules, is a useful tool in analysing the symmetrical properties and the stabilities of DNA. This paper studies the structural properties of a super-long elastic slender rod as a structural model of DNA by using Kirchhoff's analogue technique and presents the Noether symmetries of the model by using the method of infinitesimal transformation. Baaed on Kirchhoff's analogue it analyses the generalized Hamilton canonical equations. The infinitesimal transfornaationa with rcspect to the radial coordinnte, the gonarnlizod coordinates, and the Cluasi-momenta of 5he model are introduced. The Noether gymmetries and conserved qugntities of the model are obtained.展开更多
The balcony is responsible to a series of effects on the environmental behavior of a building,mainly in relation of thermal comfort and air distribution to their indoor spaces.Currently a very common practice in sever...The balcony is responsible to a series of effects on the environmental behavior of a building,mainly in relation of thermal comfort and air distribution to their indoor spaces.Currently a very common practice in several metropolitan areas is the closing with retractable glass panels in balcony openings.This work analyzed the effects of glazed balconies upon thermal comfort in a hot tropical region.Environmental parameters were carried out in a flat alternating the conditions of retractable glass panels to balconies.Thermal simulations were performed considering closing or not the glass door that divides the balcony room;the building material used on the balcony sill;and the use of curtains or shading devices.The results show the maximum mean hourly temperatures recorded on the balcony during the period when the retractable glass panels were closed,reaching peaks between 31.7 and 39.2°C,above the comfort range recommended by ASHRAE 55.All situations simulated show the thermal discomfort prevails in the use of the closed glass panels reaching DhTD of 94.55°C/day.Thus,this practice of using most of the closed retractable glass panels in the balconies presents disadvantages and inefficiencies especially in hot and humid tropical climate regions.展开更多
Based on the capacity/demand(C/D)analysis of bridge components,and life cycle and performance based seismic design principles,a practical approach is developed for the seismic performance evaluation of super-long span...Based on the capacity/demand(C/D)analysis of bridge components,and life cycle and performance based seismic design principles,a practical approach is developed for the seismic performance evaluation of super-long span cable-stayed bridges.According to the approach,the seismic performance evaluation of the Sutong Bridge,which is a cable-stayed bridge with a main span of 1 088 m,is completed,and the practicality of the approach is validated.The earthquake resistance level for super-long span cable-stayed bridges is discussed,including the earthquake level,its corresponding structural performance and check indices.And a set of formula for capacity/demand ratio calculation of bridge components is proposed.展开更多
In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried ou...In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried out using a numerical simulation package(Fluent) based on gas-solid coupling dispersed multiphase flow model and field measurement to research different technology modes, dust distribution law at different intervals where shearers work in opposite directions on the lower 9303 face, No. 2 Jining Mine,Yankuang Coal Mining Co. Results show that the concentration of dust 3–6 m away from the shearers working in the same directions was large, while the impact area of respirable dust near the shearer increased significantly to 5–6 m with the distance between two shearers working in opposite directions.The concentration of dust on a double-shearer face was considerably higher than that of a face with one shear under the combined effect of wind speed on the face and disturbed wind around the shearer, while the dust concentration near the shearer on the return side was considerably higher than that on the inlet side. The concentration of dust on a double-shearer face along the airflow declined slowly so that dust was hard to control. Simulation results confirmed the results of field measurement, which could provide reference for dust prevention design.展开更多
The prediction of the stress field of deep-buried tunnels is a fundamental problem for scientists and engineers. In this study, the authors put forward a systematic solution for this problem. Databases from the World ...The prediction of the stress field of deep-buried tunnels is a fundamental problem for scientists and engineers. In this study, the authors put forward a systematic solution for this problem. Databases from the World Stress Map and the Crustal Stress of China, and previous research findings can offer prediction of stress orientations in an engineering area. At the same time, the Andersonian theory can be used to analyze the possible stress orientation of a region. With limited in-situ stress measurements, the Hock-Brown Criterion can be used to estimate the strength of rock mass in an area of interest by utilizing the geotechnical investigation data, and the modified Sheorey's model can subsequently be employed to predict the areas' stress profile, without stress data, by taking the existing in-situ stress measurements as input parameters. In this paper, a case study was used to demonstrate the application of this systematic solution. The planned Kohala hydropower plant is located on the western edge of Qinghai-Tibet Plateau. Three hydro-fracturing stress measurement campaigns indicated that the stress state of the area is SH - Sh 〉 Sv or SH 〉Sv 〉 Sh. The measured orientation of Sn is NEE (N70.3°-89°E), and the regional orientation of SH from WSM is NE, which implies that the stress orientation of shallow crust may be affected by landforms. The modified Sheorey model was utilized to predict the stress profile along the water sewage tunnel for the plant. Prediction results show that the maximum and minimum horizontal principal stres- ses of the points with the greatest burial depth were up to 56.70 and 40.14 MPa, respectively, and the stresses of areas with a burial depth of greater than 500 m were higher. Based on the predicted stress data, large deformations of the rock mass surrounding water conveyance tunnels were analyzed. Results showed that the large deformations will occur when the burial depth exceeds 300 m. When the burial depth is beyond 800 m, serious squeezing deformations will occur in the surrounding rock masses, thus requiring more attention in the design and construction. Based on the application efficiency in this case study, this prediction method proposed in this paper functions accurately.展开更多
Natural ventilation performance can be influenced by various factors,including facade treatments such as balconies.Balconies have been commonly incorporated into residential buildings for various purposes,yet the prov...Natural ventilation performance can be influenced by various factors,including facade treatments such as balconies.Balconies have been commonly incorporated into residential buildings for various purposes,yet the provision of a balcony as a passive design strategy to improve natural ventilation is not one of its common purposes.The objective of this study is to investigate the effect of balcony design on the natural ventilation performance of cross-ventilated high-rise apartments.This study uses Computational Fluid Dynamics(CFD)models to predict ventilation performance.CFD models are selected because of their accuracy,flexibility and ability to provide comprehensive data for the investigation.This study suggests that balconies in high-rise apartments could improve the ventilation performance of high-rise apartments,but that balconies can also have a negative impact on ventilation performance if not appropriately designed.Finally,this study suggests that balconies could improve the level of thermal comfort and indoor air quality of apartments by providing greater indoor air speed and better ventilation performance,respectively.展开更多
Changqing Yellow River Super-long Bridge of Zhengzhou-Ji'nan HSR is a partial cable-stayed bridge with concrete main girder and a unit length of 1,080 m.Studies are carried out on the key technologies of bridge de...Changqing Yellow River Super-long Bridge of Zhengzhou-Ji'nan HSR is a partial cable-stayed bridge with concrete main girder and a unit length of 1,080 m.Studies are carried out on the key technologies of bridge design,and the main conclusions are as follows:The whole unit adopts the supporting system of tower pier consolidation and tower-beam separation,and each pier is provided with seismic mitigation and isolation bearing;shaped-steel reinforced concrete bridge tower is adopted to bring into full play the tensile performance of steel and the compressive performance of concrete,and avoid the construction challenges of setting up multi-layer and multi-stirrup reinforcement while improving the bearing capacity of section;a new type of double-side and bi-directional anti-skid anchorage device is adopted for the cable saddle of wire divider pipe in order to withstand the unbalanced cable force,and verify the reliability of the anti-skid anchorage device by solid model test;and large-segment cantilever pouring design is adopted for the main girder with a maximum segment length of 8 m to effectively shorten the construction period of the bridge.展开更多
【目的】住宅阳台作为重要的家庭生活空间,其环境的疗愈性逐渐成为人居环境领域研究的新议题,明确疗愈视角下住宅阳台环境研究的进展和发展趋势,形成系统性认知,对提升居住环境品质、增进健康福祉具有重要的理论和现实意义。【方法】以...【目的】住宅阳台作为重要的家庭生活空间,其环境的疗愈性逐渐成为人居环境领域研究的新议题,明确疗愈视角下住宅阳台环境研究的进展和发展趋势,形成系统性认知,对提升居住环境品质、增进健康福祉具有重要的理论和现实意义。【方法】以阳台疗愈环境研究为视角,以Web of Science核心合集、中国知网数据库为依据,对国内外相关的研究脉络、内容及方法进行梳理和分析,评述当前研究的现状、趋势、局限与不足。【结果】阳台疗愈环境研究可以分为“环境—感知”“环境—行为”“环境—生态”3个方面,经历了由物理环境效应到感知恢复,再到身心疗愈的渐进式过程。总结了阳台环境在感知、行为、生态方面的疗愈效益,评述了身心融合、多元统一的研究历程和新兴技术支持下研究范式的转变,展望了人与环境交互的阳台环境效益与因果关系、影响要素与疗愈机制、空间配置与综合利用的研究方向。【结论】有助于推动阳台研究的深化,为住宅阳台环境设计与优化提供理论依据,促进阳台的多样化利用,提升居民的健康福祉。展开更多
基金School-level innovation training project of Chongqing Institute of Technology-New Building Landscape Balcony(No.CXCY2023066)School-level project of Chongqing Institute of Technology:Research on Urban Waterfront Landscape Design Based on the Concept of River Ecological Restoration-Taking the Chongqing Institute of Technology Section of Huaxi River as an Example(No.2022xskz02)。
文摘With the acceleration of urbanization and the improvement of people’s living standards,people have increasingly higher requirements for the living environment,especially in the design of outdoor balconies.However,existing landscape balconies generally suffer from insufficient shading and rainwater drainage problems,which affects people’s living experience.In response to this problem,this article proposes a new design scheme for building landscape balconies to solve the existing problems of landscape balconies.This design plan fully considers the user’s usage needs and scenarios,improves the use value and comfort of the balcony through technical means,and achieves intelligence and functionality.
基金The Natural Science Foundation of Hubei Province(No.2007ABA094)
文摘A centrifuge modeling test and a three-dimensional finite element analysis(FEA)of super-long rock-socketed bored pile groups of the Tianxingzhou Bridge are proposed.Based on the similarity theory,different prototypical materials are simulated using different indicators in the centrifuge model.The silver sand,the shaft and the pile cap are simulated according to the natural density,the compressive stiffness and the bending stiffness,respectively.The finite element method(FEM)is implemented and analyzed in ANSYS,in which the stress field during the undisturbed soil stage,the boring stage,the concrete-casting stage and the curing stage are discussed in detail.Comparisons in terms of load-settlement,shaft axial force distribution and lateral friction between the numerical results and the test data are carried out to investigate the bearing behaviors of super-long rock-socketed bored pile groups under loading and unloading conditions.Results show that there is a good agreement between the centrifuge modeling tests and the FEM.In addition,the load distribution at the pile top is complicated,which is related to the stiffness of the cap,the corresponding assumptions and the analysis method.The shaft axial force first increases slightly with depth then decreases sharply,and the rate of decrease in rock is greater than that in sand and soil.
基金financially supported by the National Natural Science Foundation of China(Nos.21872045 and 21975069)the Key Project of Research and Development Plan of Hunan Province(Grant 2019SK2071)+1 种基金the Natural Science Foundation of Hunan Province(2020JJ4169)support from the Development and Reform Commission of Hunan Province.
文摘Studies have found that oxygen-rich-containing functional groups in carbon-based materials can be used as active sites for the storage performance of K^(+),but the basic storage mechanism is still unclear.Herein,we construct and optimize 3D honeycomb-like carbon grafted with plentiful COOH/C=O functional groups(OFGC)as anodes for potassium ion batteries.The OFGC electrode with steady structure and rich functional groups can effectively contribute to the capacity enhancement and the formation of stable solid electrolyte interphase(SEI)film,achieving a high reversible capacity of 230 mAh g^(-1) at 3000 mA g^(-1) after 10,000 cycles(almost no capacity decay)and an ultra-long cycle time over 18 months at 100 mA g^(-1).The study results revealed the reversible storage mechanism between K^(+)and COOH/C=O functional groups by forming C-O-K compounds.Meanwhile,the in situ electrochemical impedance spectroscopy proved the highly reversible and rapid de/intercalation kinetics of K+in the OFGC electrode,and the growth process of SEI films.In particular,the full cells assembled by Prussian blue cathode exhibit a high energy density of 113 Wh kg^(-1) after 800 cycles(calculated by the total mass of anode and cathode),and get the light-emitting diodes lamp and ear thermometer running.
基金Project(50908084)supported by the National Natural Science Foundation of ChinaProject(200815)supported by the Transportation Science and Technology Program of Hunan Province,ChinaProject(531107040620)supported by the Growth Plan for Young Teachers of Hunan University,China
文摘In order to find out the bearing behavior of super-long piles located in deep soft clay over stiff layers around Dongting Lake, China, a test pile was first designed with the field loading test finished afterward. Based on the measured test results, load transfer mechanism and bearing behavior of the pile shaft were discussed in detail. Then, by introducing a bi-linear model for shaft friction and the tri-linear model for pile tip resistance, respectively, the governing differential equation of pile soil system was set up by the load transfer method with the analytical solutions derived as well, taking into account the effect by stratified feature and various bearing conditions of subsoil, material nonlinearity, and the sediment under pile tip. Furthermore, formulas to determine the axial capacity of super-long piles by the pile top settlement were advised and applied to analyze the test pile. Good agreement between the predicted load settlement variations and the measured data is obtained to verify the validity of the present method. The results also show that, the axial bearing capacity of super-long piles should be controlled by the allowable pile top settlement, and buckling stability of the pile shaft should be paid attention as well.
基金supported by European Research Council(HiNaPc:737616)European Research Council(ThreeDsurface:240144)+8 种基金BMBF(ZIK-3DNanoDevice:03Z1MN11)DFG(LE2249_4-1)BMBF(Meta-ZIK-BioLithoMorphie:03Z1M511)National Natural Science Foundation of China(Nos.21577086,51702130,21503209)Natural Science Foundation of Jiangsu Province(BK 20170550)Jiangsu Specially-Appointed Professor ProgramHundred-Talent Program(Chinese Academy of Sciences)Beijing Natural Science Foundation(No.2162042)Key Research Program of Frontier Science,CAS(No.QYZDBSSW-SLH006)
文摘Nanowire(NW) structures is an alternative candidate for constructing the next generation photoelectrochemical water splitting system, due to the outstanding optical and electrical properties. NW photoelectrodes comparing to traditional semiconductor photoelectrodes shows the comparatively shorter transfer distance of photo-induced carriers and the increase amount of the surface reaction sites, which is beneficial for lowering the recombination probability of charge carriers and improving their photoelectrochemical(PEC) performances. Here, we demonstrate for the first time that super-long Cu_2O NWs, more than 4.5 μm,with highly efficient water splitting performance, were synthesized using a cost-effective anodic alumina oxide(AAO) template method. In comparison with the photocathode with planar Cu_2O films, the photocathode with Cu_2O NWs demonstrates a significant enhancement in photocurrent, from –1.00 to –2.75 mA/cm^2 at –0.8 V versus Ag/AgCl. After optimization of the photoelectrochemical electrode through depositing Pt NPs with atomic layer deposition(ALD) technology on the Cu_2O NWs, the plateau of photocurrent has been enlarged to –7 mA/cm^2 with the external quantum yield up to 34% at 410 nm. This study suggests that the photoelectrode based on Cu_2O NWs is a hopeful system for establishing high-efficiency water splitting system under visible light.
基金Project(50378036) supported by the National Natural Science Foundation of China
文摘In order to discuss the buckling stability of super-long rock-socketed filling piles widely used in bridge engineering in soft soil area such as Dongting Lake, the second stability type was adopted instead of traditional first type, and a newly invented numerical analysis method, i.e. the element-free Galerkin method (EFGM), was introduced to consider the non-concordant deformation and nonlinearity of the pile-soil interface. Then, based on the nonlinear elastic-ideal plastic pile-soil interface model, a nonlinear iterative algorithm was given to analyze the pile-soil interaction, and a program for buckling analysis of piles by the EFGM (PBAP-EFGM) and arc length method was worked out as well. The application results in an engineering example show that, the shape of pile top load-settlement curve obtained by the program agrees well with the measured one, of which the difference may be caused mainly by those uncertain factors such as possible initial defects of pile shaft and the eccentric loading during the test process. However, the calculated critical load is very close with the measured ultimate load of the test pile, and the corresponding relative error is only 5.6%, far better than the calculated values by linear and nonlinear incremental buckling analysis (with a greater relative error of 37.0% and 15.4% respectively), which also verifies the rationality and feasibility of the present method.
文摘The total length of the second stage of the water supply project in the northern areas of the Xinjiang Uygur Autonomous Region is 540 km, of which the total length of the tunnels is 516 km. The total tun- neling mileage is 569 km, which includes 49 slow-inclined shafts and vertical shafts. Among the tunnels constructed in the project, the Ka-Shuang tunnel, which is a single tunnel with a length of 283 kin, is cur- rently the longest water-conveyance tunnel in the world. The main tunnel of the Ka-Shuang tunnel is divided into 18 tunnel-boring machine (TBM) sections, and 34 drilling-and-blasting sections, with 91 tunnel faces. The construction of the Ka-Shuang tunnel has been regarded as an unprecedented challenge for project construction management, risk control, and safe and efficient construction; it has also pre- sented higher requirements for the design, manufacture, operation, and maintenance of the TBMs and their supporting equipment. Based on the engineering characteristics and adverse geological conditions, it is necessary to analyze the major problems confronted by the construction and systematically locate disaster sources. In addition, the risk level should be reasonably ranked, responsibility should be clearly identified, and a hierarchical-control mechanism should be established. Several techniques are put for- ward in this paper to achieve the objectives mentioned above; these include advanced geological prospecting techniques, intelligent tunneling techniques combined with the sensing and fusion of infor- mation about rock parameters and mechanical parameters, monitoring and early-warning techniques, and modern information technologies. The application of these techniques offers scientific guidance for risk control and puts forward technical ideas about improving the efficiency of safe tunneling. These techniques and ideas have great significance for the development of modern tunneling technolo- gies and research into major construction equipment.
基金Project supported by the Natural Science Foundation of Shandong Province of China (Grant No. ZR2009AQ011)Science Foundation of Binzhou University,China (Grant No. BZXYG0903)
文摘This paper analyses perturbations of Noether symmetry, Lie symmetry, and form invariance for super-long elastic slender rod systems. Criterion and structure equations of the symmetries after disturbance are proposed. Considering perturbation of all infinitesimal generators, three types of adiabatic invariants induced by perturbation of symmetries for the system are obtained.
基金Supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China(No.20100732002)the National Natural Science Foundation of China(No.21004006)+2 种基金the Research Foundation for the Doctoral Program of Higher Education of China(No.20101101120036)the 111 Project in China(No.B07012)the Program for the New Century Excellent Talents in Universities of China(No.NCET-10-0047)
文摘Electrochemical cyclic voltammetric(CV) scan was applied to inducing the partial oxidation and defects of carbon nanotubes(CNTs).The electrochemically induced functional groups and physical defects were demonstrated to show positive effects on the nanotube capacitance,as exemplified by super-long CNT arrays as model for the easy fabrication of CNT electrodes.Specifically,the initial hydrophobic nanotube surface becomes hydrophilic and a ten-time enhancement in capacitance is observed with respect to the pristine CNT sample.Thus,the electrochemical CV pretreatment can be used as an effective approach to activate the CNT surface for an enhanced electrochemical performance in capacitors,and many other advanced devices beyond capacitors,such as electrochemical sensors and batteries.
基金supported by the National Natural Science Foundation of China (Grant Nos 10672143 and 60575055)the State Key Laboratory of Scientific and Engineering ComputingChinese Academy of Sciences and the Natural Science Foundation of Henan Province Government of China (Grant No 0511022200)
文摘DNA is a nucleic acid molecule with double-helical structures that are special symmetrical structures attracting great attention of numerous researchers. The super-long elastic slender rod, an important structural model of DNA and other long-train molecules, is a useful tool in analysing the symmetrical properties and the stabilities of DNA. This paper studies the structural properties of a super-long elastic slender rod as a structural model of DNA by using Kirchhoff's analogue technique and presents the Noether symmetries of the model by using the method of infinitesimal transformation. Baaed on Kirchhoff's analogue it analyses the generalized Hamilton canonical equations. The infinitesimal transfornaationa with rcspect to the radial coordinnte, the gonarnlizod coordinates, and the Cluasi-momenta of 5he model are introduced. The Noether gymmetries and conserved qugntities of the model are obtained.
文摘The balcony is responsible to a series of effects on the environmental behavior of a building,mainly in relation of thermal comfort and air distribution to their indoor spaces.Currently a very common practice in several metropolitan areas is the closing with retractable glass panels in balcony openings.This work analyzed the effects of glazed balconies upon thermal comfort in a hot tropical region.Environmental parameters were carried out in a flat alternating the conditions of retractable glass panels to balconies.Thermal simulations were performed considering closing or not the glass door that divides the balcony room;the building material used on the balcony sill;and the use of curtains or shading devices.The results show the maximum mean hourly temperatures recorded on the balcony during the period when the retractable glass panels were closed,reaching peaks between 31.7 and 39.2°C,above the comfort range recommended by ASHRAE 55.All situations simulated show the thermal discomfort prevails in the use of the closed glass panels reaching DhTD of 94.55°C/day.Thus,this practice of using most of the closed retractable glass panels in the balconies presents disadvantages and inefficiencies especially in hot and humid tropical climate regions.
基金National Key Technologies R&D Program(No.2006BAG04B01),research on technical standards,key structures and their characteristics of kilometer-magnitude cable-stayed bridges
文摘Based on the capacity/demand(C/D)analysis of bridge components,and life cycle and performance based seismic design principles,a practical approach is developed for the seismic performance evaluation of super-long span cable-stayed bridges.According to the approach,the seismic performance evaluation of the Sutong Bridge,which is a cable-stayed bridge with a main span of 1 088 m,is completed,and the practicality of the approach is validated.The earthquake resistance level for super-long span cable-stayed bridges is discussed,including the earthquake level,its corresponding structural performance and check indices.And a set of formula for capacity/demand ratio calculation of bridge components is proposed.
基金the National Natural Science Foundation of China (No.51404249)the Basic Research Program of Jiangsu Province (No.BK20140201)the Priority Academic Program Development of Jiangsu Higher Education Institutions for financial support provided during this research
文摘In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried out using a numerical simulation package(Fluent) based on gas-solid coupling dispersed multiphase flow model and field measurement to research different technology modes, dust distribution law at different intervals where shearers work in opposite directions on the lower 9303 face, No. 2 Jining Mine,Yankuang Coal Mining Co. Results show that the concentration of dust 3–6 m away from the shearers working in the same directions was large, while the impact area of respirable dust near the shearer increased significantly to 5–6 m with the distance between two shearers working in opposite directions.The concentration of dust on a double-shearer face was considerably higher than that of a face with one shear under the combined effect of wind speed on the face and disturbed wind around the shearer, while the dust concentration near the shearer on the return side was considerably higher than that on the inlet side. The concentration of dust on a double-shearer face along the airflow declined slowly so that dust was hard to control. Simulation results confirmed the results of field measurement, which could provide reference for dust prevention design.
基金provided by the National Natural Science Foundation of China – China (No. 41274100)the Fundamental Research Fund for State Level Scientific Institutes (No. ZDJ2012-20)
文摘The prediction of the stress field of deep-buried tunnels is a fundamental problem for scientists and engineers. In this study, the authors put forward a systematic solution for this problem. Databases from the World Stress Map and the Crustal Stress of China, and previous research findings can offer prediction of stress orientations in an engineering area. At the same time, the Andersonian theory can be used to analyze the possible stress orientation of a region. With limited in-situ stress measurements, the Hock-Brown Criterion can be used to estimate the strength of rock mass in an area of interest by utilizing the geotechnical investigation data, and the modified Sheorey's model can subsequently be employed to predict the areas' stress profile, without stress data, by taking the existing in-situ stress measurements as input parameters. In this paper, a case study was used to demonstrate the application of this systematic solution. The planned Kohala hydropower plant is located on the western edge of Qinghai-Tibet Plateau. Three hydro-fracturing stress measurement campaigns indicated that the stress state of the area is SH - Sh 〉 Sv or SH 〉Sv 〉 Sh. The measured orientation of Sn is NEE (N70.3°-89°E), and the regional orientation of SH from WSM is NE, which implies that the stress orientation of shallow crust may be affected by landforms. The modified Sheorey model was utilized to predict the stress profile along the water sewage tunnel for the plant. Prediction results show that the maximum and minimum horizontal principal stres- ses of the points with the greatest burial depth were up to 56.70 and 40.14 MPa, respectively, and the stresses of areas with a burial depth of greater than 500 m were higher. Based on the predicted stress data, large deformations of the rock mass surrounding water conveyance tunnels were analyzed. Results showed that the large deformations will occur when the burial depth exceeds 300 m. When the burial depth is beyond 800 m, serious squeezing deformations will occur in the surrounding rock masses, thus requiring more attention in the design and construction. Based on the application efficiency in this case study, this prediction method proposed in this paper functions accurately.
文摘Natural ventilation performance can be influenced by various factors,including facade treatments such as balconies.Balconies have been commonly incorporated into residential buildings for various purposes,yet the provision of a balcony as a passive design strategy to improve natural ventilation is not one of its common purposes.The objective of this study is to investigate the effect of balcony design on the natural ventilation performance of cross-ventilated high-rise apartments.This study uses Computational Fluid Dynamics(CFD)models to predict ventilation performance.CFD models are selected because of their accuracy,flexibility and ability to provide comprehensive data for the investigation.This study suggests that balconies in high-rise apartments could improve the ventilation performance of high-rise apartments,but that balconies can also have a negative impact on ventilation performance if not appropriately designed.Finally,this study suggests that balconies could improve the level of thermal comfort and indoor air quality of apartments by providing greater indoor air speed and better ventilation performance,respectively.
文摘Changqing Yellow River Super-long Bridge of Zhengzhou-Ji'nan HSR is a partial cable-stayed bridge with concrete main girder and a unit length of 1,080 m.Studies are carried out on the key technologies of bridge design,and the main conclusions are as follows:The whole unit adopts the supporting system of tower pier consolidation and tower-beam separation,and each pier is provided with seismic mitigation and isolation bearing;shaped-steel reinforced concrete bridge tower is adopted to bring into full play the tensile performance of steel and the compressive performance of concrete,and avoid the construction challenges of setting up multi-layer and multi-stirrup reinforcement while improving the bearing capacity of section;a new type of double-side and bi-directional anti-skid anchorage device is adopted for the cable saddle of wire divider pipe in order to withstand the unbalanced cable force,and verify the reliability of the anti-skid anchorage device by solid model test;and large-segment cantilever pouring design is adopted for the main girder with a maximum segment length of 8 m to effectively shorten the construction period of the bridge.
文摘【目的】住宅阳台作为重要的家庭生活空间,其环境的疗愈性逐渐成为人居环境领域研究的新议题,明确疗愈视角下住宅阳台环境研究的进展和发展趋势,形成系统性认知,对提升居住环境品质、增进健康福祉具有重要的理论和现实意义。【方法】以阳台疗愈环境研究为视角,以Web of Science核心合集、中国知网数据库为依据,对国内外相关的研究脉络、内容及方法进行梳理和分析,评述当前研究的现状、趋势、局限与不足。【结果】阳台疗愈环境研究可以分为“环境—感知”“环境—行为”“环境—生态”3个方面,经历了由物理环境效应到感知恢复,再到身心疗愈的渐进式过程。总结了阳台环境在感知、行为、生态方面的疗愈效益,评述了身心融合、多元统一的研究历程和新兴技术支持下研究范式的转变,展望了人与环境交互的阳台环境效益与因果关系、影响要素与疗愈机制、空间配置与综合利用的研究方向。【结论】有助于推动阳台研究的深化,为住宅阳台环境设计与优化提供理论依据,促进阳台的多样化利用,提升居民的健康福祉。