Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely comme...Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.展开更多
A new microelement method for the analyses of functionally graded structures was proposed. The key of this method is the maneuverable combination of two kinds of elements. Firstly, the macro elements are divided from ...A new microelement method for the analyses of functionally graded structures was proposed. The key of this method is the maneuverable combination of two kinds of elements. Firstly, the macro elements are divided from the functionally graded material structures by the normal finite elements. In order to reflect the functionally graded distributions of materials and the microconstitutions in each macro-element, the microelement method sets up the dense microelements in every macro-element, and translates nodes to the same as the normal finite elements by the degrees of freedom of all microelemental the compatibility conditions. This microelement method can fully reflect the micro constitutions and different components of materials, and its computational elements are the same as the normal finite elements, so it is an effective numerical method for the analyses of the functionally graded material structures. The three-dimensional analyses of functionally graded plates with medium components and different micro net structures are given by using the microelement method in this paper. The differences of the stress contour in the plane of functionally graded plates with different net microstructures are especially given in this paper.展开更多
Introduction In recent years, the syntheses, properties and applications of the complexes of transition-metal ions with Schiff bases have been a very interesting subject in coordination chemistry. It has been clearly ...Introduction In recent years, the syntheses, properties and applications of the complexes of transition-metal ions with Schiff bases have been a very interesting subject in coordination chemistry. It has been clearly stated that some of them have certain antitumor展开更多
With the increment of the complexity of structural systems and the span of spatial structures, the interactions between parts of the structures, especially between some flexible substructures, become too complex to be...With the increment of the complexity of structural systems and the span of spatial structures, the interactions between parts of the structures, especially between some flexible substructures, become too complex to be analyzed clearly. In this paper, taking an actual gymnasium of a long-span spatial steel-cable-membrane hybrid structure as the calculation model, the static and dynamic analyses of the hybrid structures are performed by employing the global analysis of the whole hybrid structure and the substructural analysis of the truss arch substructure, the cable-membrane substructure, etc. In addition, the comparison of stresses and displacements of structural members in the global and substructural analyses is made. The numerical results show that serious errors exist in the substructural analysis of the hybrid structure, and the global analysis is necessary for the hybrid structure under the excitation of static loads and seismic loads.展开更多
This work presents method of the quality analyses of the photorealistic images. Developed method utilizes proposed criteria of image definition quality for fine details. Presented method has the following significant ...This work presents method of the quality analyses of the photorealistic images. Developed method utilizes proposed criteria of image definition quality for fine details. Presented method has the following significant property: the quality estimation is provided without test images or patterns. Algorithm for search and recognition of fine structures in the photorealistic images using the predefined criterion is considered.展开更多
Previous studies on the relationship between exPosure to televised violence and viewers' aggressive behaviours have produced mixed results. Some studies have found significant effect sizes while others have found low...Previous studies on the relationship between exPosure to televised violence and viewers' aggressive behaviours have produced mixed results. Some studies have found significant effect sizes while others have found low and non-significant effect sizes. Television effects scholars have postulated that these mixed results are caused by the inconsistencies of research methodology employed and the inability to control major mediating variables in the studies. The present study is designed with the objectives to overcome these shortcomings. The respondents for this study were 514 students aged between 13 and 18 from 10 schools in the State of Perak, Malaysia. Exploratory data analyses provided evidence that the employed instruments achieved sound psychometric properties. Hypotheses testing suggested that exposure to the Contents of Television Violence (TVCN) did not have a direct relationship with adolescents' aggressive behaviours; instead, Contextual Features of Television Violence (TVCX) totally mediated this relationship. Some other mediating variables then mediated totally and some mediated partially the relationship between TVCX and adolescents' aggressive behaviours. To conclude, this study provides valuable information for parents, the television industry, and the policy makers in recognizing pro-violent and anti-violent features of television violence programmes for Malaysian school-going adolescents. It also provides a new perspective for future studies of television violence in Malaysia.展开更多
A dynamic finite element method combined with finite element mixed formula for contact problem is used to analyze the dynamic characteristics of gear system. Considering the stiffness excitation, error excitation and ...A dynamic finite element method combined with finite element mixed formula for contact problem is used to analyze the dynamic characteristics of gear system. Considering the stiffness excitation, error excitation and meshing shock excitation, the dynamic finite element model is established for the entire gear system which includes gears, shafts, bearings and gearbox housing. By the software of I-DEAS, the natural frequency, normal mode, dynamic time-domain response, frequency-domain response and one-third octave velocity grade structure borne noise of gear system are studied by the method of theoretical modal analysis and dynamic response analysis. The maximum values of vibration and structure borne noise are occurred at the mesh frequency of output grade gearing.展开更多
Stress distribution in the gradient multi-layered surface under a sliding contact was investigated using finite element method(FEM). The main structure parameters of layered surface discussed are total layer thickness...Stress distribution in the gradient multi-layered surface under a sliding contact was investigated using finite element method(FEM). The main structure parameters of layered surface discussed are total layer thickness,layer number and elastic modulus ratio of layer to the substrate. A model of multi-layered surface contact with rough slider was studied. The effect of the surface structure parameters on the elastic-plastic deformation was analyzed.展开更多
The goal of this work is to investigate the seismic behaviour of plan-asymmetric structures by considering the least seismic-resistant directions and the spatial features of the seismic event. New tools for the analys...The goal of this work is to investigate the seismic behaviour of plan-asymmetric structures by considering the least seismic-resistant directions and the spatial features of the seismic event. New tools for the analysis of the seismic behaviour of plan-asymmetric structures are herein presented and the concepts of "Polar Spectrum" and limit domains are discussed. In particular, the capacity of the structure is described by using the limit domains based on the Non Linear Static Procedures, while the seismic demand is analysed by introducing a new representation of the spectral response. This representation is based on the construction of a spectral surface obtained by the spectral seismic response for different in-plan directions and the in-plan projection of this surface is herein defined "Polar Spectrum". The obtained results for two benchmark structures, verified by means of non-linear incremental dynamic analyses, have pointed out that non-linear static analyses, carried out for different in-plan directions of the incoming seismic action, have allowed us to accurately evaluate the least seismic resistant directions.展开更多
Rod element and shell element were used in finite element software ABAQUS to establish dynamic elastic-plastic analysis model of the structure,the seismic performance of an irregular plane complex overrun structure nu...Rod element and shell element were used in finite element software ABAQUS to establish dynamic elastic-plastic analysis model of the structure,the seismic performance of an irregular plane complex overrun structure numerical simulation,the structure was calculated under different input level and displacement response of the acceleration response,and analyses the force of the wear layer column and the floor of the open hole stress level.The results were compared with the shaking table test to verify the accuracy of the numerical simulation results.The results of numerical calculation were basically consistent with the experimental results,and the finite element model basically reflected the response of the structure under the simulated earthquake.展开更多
In-vessel components are important parts of the EAST superconducting tokamak. They include the plasma facing components, passive plates, cryo-pumps, in-vessel coils, etc. The structural design, analysis and related R...In-vessel components are important parts of the EAST superconducting tokamak. They include the plasma facing components, passive plates, cryo-pumps, in-vessel coils, etc. The structural design, analysis and related R&D have been completed. The divertor is designed in an up-down symmetric configuration to accommodate both double null and single null plasma operation. Passive plates are used for plasma movement control. In-vessel coils are used for the active control of plasma vertical movements. Each cryo-pump can provide an approximately 45 m^3/s pumping rate at a pressure of 10^-1 Pa for particle exhaust. Analysis shows that, when a plasma current of 1 MA disrupts in 3 ms, the EM loads caused by the eddy current and the halo current in a vertical displacement event (VDE) will not generate an unacceptable stress on the divertor structure. The bolted divertor thermal structure with an active cooling system can sustain a load of 2 MW/m^2 up to a 60 s operation if the plasma facing surface temperature is limited to 1500 ℃. Thermal testing and structural optimization testing were conducted to demonstrate the analysis results.展开更多
A novel manganese(Ⅱ) coordination polymer [Mn(L^1)2(H2O)]·2H2O (HL^1 = 2,6- dichlorobenzoic acid) 1 has been synthesized and structurally characterized. X-ray diffraction analyses reveal that 1 is a one-...A novel manganese(Ⅱ) coordination polymer [Mn(L^1)2(H2O)]·2H2O (HL^1 = 2,6- dichlorobenzoic acid) 1 has been synthesized and structurally characterized. X-ray diffraction analyses reveal that 1 is a one-dimensional chain structure bridged by water molecules and 2,6- dichlorobenzoic acid. The crystal is of monoclinic, space group P21/c with α = 12.9701(19), b = 20.592(3), c = 7.3759(10) A, β = 102.660(2)°, V = 1.9221(5). nm^3, Z = 4, C14H12Cl4MnO7, Mr= 488.98, Dc= 1.690 g/cm^3, p = 1.275 mm^-1, F(000) = 980, Rint = 0.0348, R = 0.0350, and wR = 0.0755. In the crystal the manganese atom is six-coordinated by two oxygen atoms from water and four oxygen atoms from four 2,6-dichlorobenzolate molecules, completing an octahedral geometry.展开更多
A novel tetranuclear nickel(II) complex [NiaL2(DMF)2(H20)2'2DMF] (1, H4L = azo-enolic-2-hydroxybenzamide, DMF = N,N-dimethyl-formamide) has been synthesized and characterized by elemental analysis, UV, IR and...A novel tetranuclear nickel(II) complex [NiaL2(DMF)2(H20)2'2DMF] (1, H4L = azo-enolic-2-hydroxybenzamide, DMF = N,N-dimethyl-formamide) has been synthesized and characterized by elemental analysis, UV, IR and X-ray single-crystal diffraction characterization. Complex 1 crystallizes in the monoclinic system, space group P21/n with a = 8.8944(11), b = 14.4583(18), c = 18.097(2) A, fl = 90.00(2), Z = 2 , V = 2327.2(5) A3, C40H48NI2Ni4OI4, Mr = 1155.66, Dc= 1.649 g/cm3,μ=1.672 mm1, F(000) = 1192, R = 0.0392 and wR = 0.0958. The local coordination environment around the nickel ions exist a distorted octahedral and quadrangle geometry in the molecular structure. Complex 1 exhibits strong photoluminescent emission in the ultraviolet region at room temperature. The electrochemical studies reveal that redox of Nia+/Ni2+ in the complex is a quasi-reversible process.展开更多
In order to clarify the damage mechanism of the subway structure, the dynamic soil-structure interaction and the dynamic forces acting on the structure, a series of shaking table tests and simulation analyses were per...In order to clarify the damage mechanism of the subway structure, the dynamic soil-structure interaction and the dynamic forces acting on the structure, a series of shaking table tests and simulation analyses were performed. The seismic response of the structure and the dynamic forces acting on the structure due to sinusoidal and random waves were investigated with special attention to the dynamic soil-structure interaction. The result shows that the compression seismic soil pressures and extension seismic soil pressures simultaneously act on the sidewalls, and big shear stress also acts on the ceiling slab due to horizontal excitation. The seismic soil pressure could be approximated to hyperbola curve, and reached a peak value with increase of the shear strain of the model ground. In addition, a slide and exfoliation phenomenon between the structure and the surrounding ground was simulated, using the nonlinear analyses. The foundation is provided for amending the calculation method of seismic soil pressure and improving the anti-earthquake designing level of underground structure.展开更多
A novel trinuclear nickel(II) complex [Ni3(bushz)z(Himdz)2(H20)2].2DMF (1, bushz = N-butylsalicylhydrazide, Himdz = imidazole, DMF = N,N-dimethyl-forrnamide) has been synthesized and characterized by X-ray s...A novel trinuclear nickel(II) complex [Ni3(bushz)z(Himdz)2(H20)2].2DMF (1, bushz = N-butylsalicylhydrazide, Himdz = imidazole, DMF = N,N-dimethyl-forrnamide) has been synthesized and characterized by X-ray single-crystal diffraction characterization. Complex 1 crystallizes in the monoclinic system, space group P2 1/c with a = 7.706(7), b = 14.882(6), c = 18.639(6) A, β = 108.08(2)°, V= 2032(1) A3, Dc = 1.525 g/cm3, Mr = 932.95, Z= 2, F(000) = 972,μ = 1.442 mm-1, the final R = 0.0359 and wR = 0.0771. The three nickel(II) atoms in 1 are arranged in a strictly linear structure and exhibit alternating square-planar and octahedral geometries. The complex is connected to form a supramolecule with an infinite three-dimensional network through intermolecular hydrogen bonds. The electrochemical studies reveal that redox of Ni3+/Ni2+ in the complex is a quasi-reversible process. The thermal stability of the title complex was also studied.展开更多
Isolated, relic populations of Acer grandidentatum (bigtooth maple, Sapindaceae) were found in deep canyons in central Texas. Associated with them on hilltops were communities of Juniperus ashei (ash juniper). We dete...Isolated, relic populations of Acer grandidentatum (bigtooth maple, Sapindaceae) were found in deep canyons in central Texas. Associated with them on hilltops were communities of Juniperus ashei (ash juniper). We determined the structure of relic A. grandidentatum populations and compared them to adjacent J. ashei populations. The overstory and understory density was counted and basal area was determined for all woody species in both communities using the quadrat procedure. Acer grandidentatum was the highest density (788 ± 964 or 52%) and basal area (29 ± 35 or 52%) overstory species in the canyon communities while J. ashei had the highest density (1589 ± 146 or 92%) and basal area (51 ± 13 or 88%) in the hilltop communities. In the understory of the canyon communities, there were five juvenile tree species including A. grandidentatum which had the fourth highest density (13% or 176 ± 110 plants/ha). In the hilltop communities, J. ashei was the high density understory tree species (52% or 994 ± 400 plants/ha). There were no A. Grandidentatum overstory or understory plants in the hilltop Juniperus communities. Acer grandidentatum had an inverse quadratic size distribution with few juveniles. Although we counted a number of seedlings, there was little recruitment over the last 16 years and very little potential recruitment in the previous 20 years. Juniperus ashei had an inverse exponential size distribution with many understory plants and considerable recruitment. Weibull age/size distributions showed one A. grandidentatum established in the 1670’s and 2 in the 1760’s, with peak establishment in the 1970’s. Causes of the lack of recent recruitment are uncertain, but it could be episodic due to changes in herbivory, management or other environmental conditions.展开更多
Common wheat (Triticum aestivum L.) is one of the most important crops, and intra-specific wheat hybrids have obvious heterosis in yield and protein quality. Therefore, utilization of hybrid wheat varieties offers a...Common wheat (Triticum aestivum L.) is one of the most important crops, and intra-specific wheat hybrids have obvious heterosis in yield and protein quality. Therefore, utilization of hybrid wheat varieties offers an effective way to increase yield and nutrition. Cytoplasmic male sterility (CMS) systems are a useful genetic tool for hybrid crop breeding, and are ideal models for studying the genetic interaction and cooperative function of mitochondrial and nuclear genomes in plants (Schnable and Wise, 1998; Hanson and Bentolila, 2004).展开更多
The Northern part of Algeria is considered to be the most active seismogenic area in the Western Mediterranean region. This area has a rich history of seismicity and had experienced many destructive earthquakes such a...The Northern part of Algeria is considered to be the most active seismogenic area in the Western Mediterranean region. This area has a rich history of seismicity and had experienced many destructive earthquakes such as the Chlef (1954), El-Asnam (1980), Beni-Chograne (1994), AYn-Temouchent (1999) and recently Boumerdes (2003) earthquakes. The earthquake of AYn-Temouchent on December 22, 1999, was of magnitude 5,7, killed at least 28 people and made thousands of families homeless. Consequent damage was seen in all the structures located in a radius of 30 kin. In the city of E1-Maleh, located 12 km northeast of Ain-Temouchent, the "The National Bank Branch" of E1-Maleh suffered moderate damage, but enough to justify questions about its safety. The project of rehabilitating this building required a broad analysis of its static and dynamic, past and present behaviors. The study reported in this paper was a necessary preliminary step toward the development of an optimal retrofit solution.展开更多
A solution of probabilistic FEM for elastic-plastic materials is presented based on the incremental theory of plasticity and a modified initial stress method. The formulations are deduced through a direct differentiat...A solution of probabilistic FEM for elastic-plastic materials is presented based on the incremental theory of plasticity and a modified initial stress method. The formulations are deduced through a direct differentiation scheme. Partial differentiation of displacement, stress and the performance function can be iteratively performed with the computation of the mean values of displacement and stress. The presented method enjoys the efficiency of both the perturbation method and the finite difference method, but avoids the approximation during the partial differentiation calculation. In order to improve the efficiency, the adjoint vector method is introduced to calculate the differentiation of stress and displacement with respect to random variables. In addition, a time-saving computational method for reliability index of elastic-plastic materials is suggested based upon the advanced First Order Second Moment (FOSM) and by the usage of Taylor expansion for displacement. The suggested method is also applicable to 3-D cases.展开更多
基金This work was supported by the National Natural Science Foundation of China(52203066,51973157,61904123)the Tianjin Natural Science Foundation(18JCQNJC02900)+3 种基金the National innovation and entrepreneurship training program for college students(202310058007)the Tianjin Municipal college students’innovation and entrepreneurship training program(202310058088)the Science&Technology Development Fund of Tianjin Education Commission for Higher Education(Grant No.2018KJ196)the State Key Laboratory of Membrane and Membrane Separation,Tiangong University.
文摘Lithium-sulfur battery(LSB)has brought much attention and concern because of high theoretical specific capacity and energy density as one of main competitors for next-generation energy storage systems.The widely commercial application and development of LSB is mainly hindered by serious“shuttle effect”of lithium polysulfides(Li PSs),slow reaction kinetics,notorious lithium dendrites,etc.In various structures of LSB materials,array structured materials,possessing the composition of ordered micro units with the same or similar characteristics of each unit,present excellent application potential for various secondary cells due to some merits such as immobilization of active substances,high specific surface area,appropriate pore sizes,easy modification of functional material surface,accommodated huge volume change,enough facilitated transportation for electrons/lithium ions,and special functional groups strongly adsorbing Li PSs.Thus many novel array structured materials are applied to battery for tackling thorny problems mentioned above.In this review,recent progresses and developments on array structured materials applied in LSBs including preparation ways,collaborative structural designs based on array structures,and action mechanism analyses in improving electrochemical performance and safety are summarized.Meanwhile,we also have detailed discussion for array structured materials in LSBs and constructed the structure-function relationships between array structured materials and battery performances.Lastly,some directions and prospects about preparation ways,functional modifications,and practical applications of array structured materials in LSBs are generalized.We hope the review can attract more researchers'attention and bring more studying on array structured materials for other secondary batteries including LSB.
基金supported by the National Natural Science Foundation of China (No.10432030)the National Youth Science Foundation of China (No.10802091)the Scientific and Technical Foundation of China University of Mining and Technology (No.2007B013)
文摘A new microelement method for the analyses of functionally graded structures was proposed. The key of this method is the maneuverable combination of two kinds of elements. Firstly, the macro elements are divided from the functionally graded material structures by the normal finite elements. In order to reflect the functionally graded distributions of materials and the microconstitutions in each macro-element, the microelement method sets up the dense microelements in every macro-element, and translates nodes to the same as the normal finite elements by the degrees of freedom of all microelemental the compatibility conditions. This microelement method can fully reflect the micro constitutions and different components of materials, and its computational elements are the same as the normal finite elements, so it is an effective numerical method for the analyses of the functionally graded material structures. The three-dimensional analyses of functionally graded plates with medium components and different micro net structures are given by using the microelement method in this paper. The differences of the stress contour in the plane of functionally graded plates with different net microstructures are especially given in this paper.
文摘Introduction In recent years, the syntheses, properties and applications of the complexes of transition-metal ions with Schiff bases have been a very interesting subject in coordination chemistry. It has been clearly stated that some of them have certain antitumor
文摘With the increment of the complexity of structural systems and the span of spatial structures, the interactions between parts of the structures, especially between some flexible substructures, become too complex to be analyzed clearly. In this paper, taking an actual gymnasium of a long-span spatial steel-cable-membrane hybrid structure as the calculation model, the static and dynamic analyses of the hybrid structures are performed by employing the global analysis of the whole hybrid structure and the substructural analysis of the truss arch substructure, the cable-membrane substructure, etc. In addition, the comparison of stresses and displacements of structural members in the global and substructural analyses is made. The numerical results show that serious errors exist in the substructural analysis of the hybrid structure, and the global analysis is necessary for the hybrid structure under the excitation of static loads and seismic loads.
文摘This work presents method of the quality analyses of the photorealistic images. Developed method utilizes proposed criteria of image definition quality for fine details. Presented method has the following significant property: the quality estimation is provided without test images or patterns. Algorithm for search and recognition of fine structures in the photorealistic images using the predefined criterion is considered.
文摘Previous studies on the relationship between exPosure to televised violence and viewers' aggressive behaviours have produced mixed results. Some studies have found significant effect sizes while others have found low and non-significant effect sizes. Television effects scholars have postulated that these mixed results are caused by the inconsistencies of research methodology employed and the inability to control major mediating variables in the studies. The present study is designed with the objectives to overcome these shortcomings. The respondents for this study were 514 students aged between 13 and 18 from 10 schools in the State of Perak, Malaysia. Exploratory data analyses provided evidence that the employed instruments achieved sound psychometric properties. Hypotheses testing suggested that exposure to the Contents of Television Violence (TVCN) did not have a direct relationship with adolescents' aggressive behaviours; instead, Contextual Features of Television Violence (TVCX) totally mediated this relationship. Some other mediating variables then mediated totally and some mediated partially the relationship between TVCX and adolescents' aggressive behaviours. To conclude, this study provides valuable information for parents, the television industry, and the policy makers in recognizing pro-violent and anti-violent features of television violence programmes for Malaysian school-going adolescents. It also provides a new perspective for future studies of television violence in Malaysia.
基金Funded by the Natural Science Foundation of China (No. 50675232)the Natural Science Foundation of CQ CSTC (2006BB3008)
文摘A dynamic finite element method combined with finite element mixed formula for contact problem is used to analyze the dynamic characteristics of gear system. Considering the stiffness excitation, error excitation and meshing shock excitation, the dynamic finite element model is established for the entire gear system which includes gears, shafts, bearings and gearbox housing. By the software of I-DEAS, the natural frequency, normal mode, dynamic time-domain response, frequency-domain response and one-third octave velocity grade structure borne noise of gear system are studied by the method of theoretical modal analysis and dynamic response analysis. The maximum values of vibration and structure borne noise are occurred at the mesh frequency of output grade gearing.
基金Project(50071014) supported by the National Natural Science Foundation of China
文摘Stress distribution in the gradient multi-layered surface under a sliding contact was investigated using finite element method(FEM). The main structure parameters of layered surface discussed are total layer thickness,layer number and elastic modulus ratio of layer to the substrate. A model of multi-layered surface contact with rough slider was studied. The effect of the surface structure parameters on the elastic-plastic deformation was analyzed.
文摘The goal of this work is to investigate the seismic behaviour of plan-asymmetric structures by considering the least seismic-resistant directions and the spatial features of the seismic event. New tools for the analysis of the seismic behaviour of plan-asymmetric structures are herein presented and the concepts of "Polar Spectrum" and limit domains are discussed. In particular, the capacity of the structure is described by using the limit domains based on the Non Linear Static Procedures, while the seismic demand is analysed by introducing a new representation of the spectral response. This representation is based on the construction of a spectral surface obtained by the spectral seismic response for different in-plan directions and the in-plan projection of this surface is herein defined "Polar Spectrum". The obtained results for two benchmark structures, verified by means of non-linear incremental dynamic analyses, have pointed out that non-linear static analyses, carried out for different in-plan directions of the incoming seismic action, have allowed us to accurately evaluate the least seismic resistant directions.
文摘Rod element and shell element were used in finite element software ABAQUS to establish dynamic elastic-plastic analysis model of the structure,the seismic performance of an irregular plane complex overrun structure numerical simulation,the structure was calculated under different input level and displacement response of the acceleration response,and analyses the force of the wear layer column and the floor of the open hole stress level.The results were compared with the shaking table test to verify the accuracy of the numerical simulation results.The results of numerical calculation were basically consistent with the experimental results,and the finite element model basically reflected the response of the structure under the simulated earthquake.
基金JSPS-CAS Core-University Program on Basic Research of Nuclear Fusion Reactor Engineering in 2007
文摘In-vessel components are important parts of the EAST superconducting tokamak. They include the plasma facing components, passive plates, cryo-pumps, in-vessel coils, etc. The structural design, analysis and related R&D have been completed. The divertor is designed in an up-down symmetric configuration to accommodate both double null and single null plasma operation. Passive plates are used for plasma movement control. In-vessel coils are used for the active control of plasma vertical movements. Each cryo-pump can provide an approximately 45 m^3/s pumping rate at a pressure of 10^-1 Pa for particle exhaust. Analysis shows that, when a plasma current of 1 MA disrupts in 3 ms, the EM loads caused by the eddy current and the halo current in a vertical displacement event (VDE) will not generate an unacceptable stress on the divertor structure. The bolted divertor thermal structure with an active cooling system can sustain a load of 2 MW/m^2 up to a 60 s operation if the plasma facing surface temperature is limited to 1500 ℃. Thermal testing and structural optimization testing were conducted to demonstrate the analysis results.
基金This work was supported by the Basic Research of Hunan Province (03JZY3036),Science Foundation of Hengyang Normal University of China (2006A15) and Foundation of the Eleventh Five-year Key Constructing Discipline of Hunan Province
文摘A novel manganese(Ⅱ) coordination polymer [Mn(L^1)2(H2O)]·2H2O (HL^1 = 2,6- dichlorobenzoic acid) 1 has been synthesized and structurally characterized. X-ray diffraction analyses reveal that 1 is a one-dimensional chain structure bridged by water molecules and 2,6- dichlorobenzoic acid. The crystal is of monoclinic, space group P21/c with α = 12.9701(19), b = 20.592(3), c = 7.3759(10) A, β = 102.660(2)°, V = 1.9221(5). nm^3, Z = 4, C14H12Cl4MnO7, Mr= 488.98, Dc= 1.690 g/cm^3, p = 1.275 mm^-1, F(000) = 980, Rint = 0.0348, R = 0.0350, and wR = 0.0755. In the crystal the manganese atom is six-coordinated by two oxygen atoms from water and four oxygen atoms from four 2,6-dichlorobenzolate molecules, completing an octahedral geometry.
基金Supported by the Key Laboratory of Environmental Engineering,Protection and Assessment of Guangxithe National Water Pollution Control and Management of China(No.2008ZX07317-02)the Startup Foundation for Dr.of Guilin University of Technology
文摘A novel tetranuclear nickel(II) complex [NiaL2(DMF)2(H20)2'2DMF] (1, H4L = azo-enolic-2-hydroxybenzamide, DMF = N,N-dimethyl-formamide) has been synthesized and characterized by elemental analysis, UV, IR and X-ray single-crystal diffraction characterization. Complex 1 crystallizes in the monoclinic system, space group P21/n with a = 8.8944(11), b = 14.4583(18), c = 18.097(2) A, fl = 90.00(2), Z = 2 , V = 2327.2(5) A3, C40H48NI2Ni4OI4, Mr = 1155.66, Dc= 1.649 g/cm3,μ=1.672 mm1, F(000) = 1192, R = 0.0392 and wR = 0.0958. The local coordination environment around the nickel ions exist a distorted octahedral and quadrangle geometry in the molecular structure. Complex 1 exhibits strong photoluminescent emission in the ultraviolet region at room temperature. The electrochemical studies reveal that redox of Nia+/Ni2+ in the complex is a quasi-reversible process.
文摘In order to clarify the damage mechanism of the subway structure, the dynamic soil-structure interaction and the dynamic forces acting on the structure, a series of shaking table tests and simulation analyses were performed. The seismic response of the structure and the dynamic forces acting on the structure due to sinusoidal and random waves were investigated with special attention to the dynamic soil-structure interaction. The result shows that the compression seismic soil pressures and extension seismic soil pressures simultaneously act on the sidewalls, and big shear stress also acts on the ceiling slab due to horizontal excitation. The seismic soil pressure could be approximated to hyperbola curve, and reached a peak value with increase of the shear strain of the model ground. In addition, a slide and exfoliation phenomenon between the structure and the surrounding ground was simulated, using the nonlinear analyses. The foundation is provided for amending the calculation method of seismic soil pressure and improving the anti-earthquake designing level of underground structure.
基金Supported by the Foundation of Fujian Educational Committee, China (No. JB10007 and JB10004)
文摘A novel trinuclear nickel(II) complex [Ni3(bushz)z(Himdz)2(H20)2].2DMF (1, bushz = N-butylsalicylhydrazide, Himdz = imidazole, DMF = N,N-dimethyl-forrnamide) has been synthesized and characterized by X-ray single-crystal diffraction characterization. Complex 1 crystallizes in the monoclinic system, space group P2 1/c with a = 7.706(7), b = 14.882(6), c = 18.639(6) A, β = 108.08(2)°, V= 2032(1) A3, Dc = 1.525 g/cm3, Mr = 932.95, Z= 2, F(000) = 972,μ = 1.442 mm-1, the final R = 0.0359 and wR = 0.0771. The three nickel(II) atoms in 1 are arranged in a strictly linear structure and exhibit alternating square-planar and octahedral geometries. The complex is connected to form a supramolecule with an infinite three-dimensional network through intermolecular hydrogen bonds. The electrochemical studies reveal that redox of Ni3+/Ni2+ in the complex is a quasi-reversible process. The thermal stability of the title complex was also studied.
文摘Isolated, relic populations of Acer grandidentatum (bigtooth maple, Sapindaceae) were found in deep canyons in central Texas. Associated with them on hilltops were communities of Juniperus ashei (ash juniper). We determined the structure of relic A. grandidentatum populations and compared them to adjacent J. ashei populations. The overstory and understory density was counted and basal area was determined for all woody species in both communities using the quadrat procedure. Acer grandidentatum was the highest density (788 ± 964 or 52%) and basal area (29 ± 35 or 52%) overstory species in the canyon communities while J. ashei had the highest density (1589 ± 146 or 92%) and basal area (51 ± 13 or 88%) in the hilltop communities. In the understory of the canyon communities, there were five juvenile tree species including A. grandidentatum which had the fourth highest density (13% or 176 ± 110 plants/ha). In the hilltop communities, J. ashei was the high density understory tree species (52% or 994 ± 400 plants/ha). There were no A. Grandidentatum overstory or understory plants in the hilltop Juniperus communities. Acer grandidentatum had an inverse quadratic size distribution with few juveniles. Although we counted a number of seedlings, there was little recruitment over the last 16 years and very little potential recruitment in the previous 20 years. Juniperus ashei had an inverse exponential size distribution with many understory plants and considerable recruitment. Weibull age/size distributions showed one A. grandidentatum established in the 1670’s and 2 in the 1760’s, with peak establishment in the 1970’s. Causes of the lack of recent recruitment are uncertain, but it could be episodic due to changes in herbivory, management or other environmental conditions.
基金supported by the National Natural Science Foundation of China(No.30971844)the Fundamental Research Funds of Northwest A & F University(No. QN2011003)+1 种基金China Postdoctoral Science Foundation to Wang Junwei(No.20070410835)the Tang Zhong-Ying Breeding Funding Project of Northwest A & F University
文摘Common wheat (Triticum aestivum L.) is one of the most important crops, and intra-specific wheat hybrids have obvious heterosis in yield and protein quality. Therefore, utilization of hybrid wheat varieties offers an effective way to increase yield and nutrition. Cytoplasmic male sterility (CMS) systems are a useful genetic tool for hybrid crop breeding, and are ideal models for studying the genetic interaction and cooperative function of mitochondrial and nuclear genomes in plants (Schnable and Wise, 1998; Hanson and Bentolila, 2004).
基金the Italian Ministry of University and Research (MIUR)
文摘The Northern part of Algeria is considered to be the most active seismogenic area in the Western Mediterranean region. This area has a rich history of seismicity and had experienced many destructive earthquakes such as the Chlef (1954), El-Asnam (1980), Beni-Chograne (1994), AYn-Temouchent (1999) and recently Boumerdes (2003) earthquakes. The earthquake of AYn-Temouchent on December 22, 1999, was of magnitude 5,7, killed at least 28 people and made thousands of families homeless. Consequent damage was seen in all the structures located in a radius of 30 kin. In the city of E1-Maleh, located 12 km northeast of Ain-Temouchent, the "The National Bank Branch" of E1-Maleh suffered moderate damage, but enough to justify questions about its safety. The project of rehabilitating this building required a broad analysis of its static and dynamic, past and present behaviors. The study reported in this paper was a necessary preliminary step toward the development of an optimal retrofit solution.
基金The project supported by the Research Grant Council of Hong Kong (HKUST 722196E, 6039197E)the National Natural Science Foundation of China(59809003)the Foundation of University Key Teacher by the Chinese Ministry of Education
文摘A solution of probabilistic FEM for elastic-plastic materials is presented based on the incremental theory of plasticity and a modified initial stress method. The formulations are deduced through a direct differentiation scheme. Partial differentiation of displacement, stress and the performance function can be iteratively performed with the computation of the mean values of displacement and stress. The presented method enjoys the efficiency of both the perturbation method and the finite difference method, but avoids the approximation during the partial differentiation calculation. In order to improve the efficiency, the adjoint vector method is introduced to calculate the differentiation of stress and displacement with respect to random variables. In addition, a time-saving computational method for reliability index of elastic-plastic materials is suggested based upon the advanced First Order Second Moment (FOSM) and by the usage of Taylor expansion for displacement. The suggested method is also applicable to 3-D cases.