A simplified full-depth precast concrete deck panel system for accelerating bridge construction （ABC） is introduced and a finite dement analysis （FEA） is con- ducted to investigate the static and dynamic responses...A simplified full-depth precast concrete deck panel system for accelerating bridge construction （ABC） is introduced and a finite dement analysis （FEA） is con- ducted to investigate the static and dynamic responses of this conceptual deck system. The FEA results are compared to those of the traditional full-depth precast concrete deck panel system. The comparison results show that the mechanical behavior of the new deck system is different from that of the traditional deck system. The concrete decks in the new system act as two-way slabs, instead of the one-way slab in the traditional system. Meanwhile, the connections in both the longitudinal and transverse direc- tions may need to accommodate the negative moments. Compared to those in the traditional system, the longitu- dinal nominal stress at middle span increases a lot in the new deck system and the effective flange width varies significantly. In addition, the dynamic results show that the impact factor is influenced by the spacing of connections. Finally, some design concerns of the new deck system are proposed.展开更多
Construction of forestry socialized service systems is the important content for reform of collective forestry tenure systems.Based on the necessity,possibility and problem of construction of forestry socialized servi...Construction of forestry socialized service systems is the important content for reform of collective forestry tenure systems.Based on the necessity,possibility and problem of construction of forestry socialized service system,according to Barnard's Organizational Structure theory,the path and countermeasure of forestry socialized service system in China are discussed.展开更多
This paper compares the satisfaction of users of residential buildings produced by two construction processes considered as industrialized:“prefabricated masonry panels”and“reinforced concrete walls molded on site...This paper compares the satisfaction of users of residential buildings produced by two construction processes considered as industrialized:“prefabricated masonry panels”and“reinforced concrete walls molded on site”and compared with“conventional process”(structural masonry of concrete blocks).The premise of the study was to diagnose the level of acceptance of the buildings considered industrialized by the Brazilian population,aiming to assess whether the preference for the systems considered“conventional”and the rejection of the“industrialized”is decreasing in Brazil.This article concerns the results obtained in the second phase of the research,which was carried out after five years of the first phase.So,if the buildings were considered new in the first phase,this second research was carried out after the depreciation due to the action of time.To quantify the“degree of satisfaction”the same checklist of the first survey was applied,in the same neighborhood and the sum attributed to each answer made by residents was applied and,as a result,it was possible to ascertain the oscillations in it and to confirm the satisfactory acceptance of industrialized construction systems and a tendency to reduce rejection by the population in relation to the innovative construction systems.展开更多
An isospectral problem with four potentials is discussed. The corresponding hierarchy of nonlinearevolution equations is derived. It is shown that the AKNS, Levi, D-AKNS hierarchies and a new oneare reductions of the ...An isospectral problem with four potentials is discussed. The corresponding hierarchy of nonlinearevolution equations is derived. It is shown that the AKNS, Levi, D-AKNS hierarchies and a new oneare reductions of the above hierarchy. In each case the relevant Hamiltonian form is established bymaking use of the trase identity.展开更多
The application of metal-organic molecular hosts as“molecular flasks”has precipitated a surge of interest in the reactivity and properties of molecules within well-defined spaces.Here we report an approach to constr...The application of metal-organic molecular hosts as“molecular flasks”has precipitated a surge of interest in the reactivity and properties of molecules within well-defined spaces.Here we report an approach to construct supramolecular systems for photo-catalytic hydrogen production and carbon dioxide reduction by encapsulating an organic dye molecule into the pocket of the redox-active metal-organic macrocycle.The assembled Ni_(3)L_(3)tricycle consists of three ligands and three nickel ions that alternately connect together.The special geometry enforces the distortion of the square planar coordinated configuration,and the coordination of the sulphur atoms enables the modification of redox potentials suitable for proton reduction and carbon dioxide reduction.The supramolecular systems that have fluorescein molecules being encapsulated as the photosensitive vips feature efficient activity for the photocatalytic carbon dioxide conversion and production reduction.The new reaction pathways within the confined space demonstrate the power of the supramolecular system over related systems.展开更多
Constructing efficient coupling systems based on the hydrogen evolution reaction(HER)and the sulfion oxidation reaction(SOR)to realize low-cost hydrogen production could promote the rapid development of the hydrogen e...Constructing efficient coupling systems based on the hydrogen evolution reaction(HER)and the sulfion oxidation reaction(SOR)to realize low-cost hydrogen production could promote the rapid development of the hydrogen economy.However,sulfion is prone to poisoning the active site,leading to a decline in catalytic activity and inferior catalytic stability.Therefore,designing efficient and stable catalysts for the SOR and exploring the inherent reaction mechanism are still formidable challenges.Herein,nickel foam-supporting Mo-doped Co_(3)S_(4) nanosheet arrays(Mo-Co-S/NF)are synthesized and exhibit robust SOR catalytic activity and high long-term durability.The doped Mo species greatly improves the electronic structure of active sites and then enhances the intrinsic activity of the SOR.Mo-Co-S/NF only requires an ultra-low potential of 0.294 V vs.RHE to achieve a current density of 100 mA cm^(-2),which is significantly lower than that for the corresponding oxygen evolution reaction(OER,1.610 V vs.RHE).What's more,Mo-Co-S/NF is further used to construct an asymmetric acid-base coupling electrolyzer based on the HER-SOR,which achieves simultaneous hydrogen and sulfur production with ultra-low energy consumption and can even generate extra electric energy at a low current density.This work provides unique insights into the design of SOR electrocatalysts and dissymmetrical electrolytes,providing more possibilities for green and low-cost hydrogen production.展开更多
文摘A simplified full-depth precast concrete deck panel system for accelerating bridge construction （ABC） is introduced and a finite dement analysis （FEA） is con- ducted to investigate the static and dynamic responses of this conceptual deck system. The FEA results are compared to those of the traditional full-depth precast concrete deck panel system. The comparison results show that the mechanical behavior of the new deck system is different from that of the traditional deck system. The concrete decks in the new system act as two-way slabs, instead of the one-way slab in the traditional system. Meanwhile, the connections in both the longitudinal and transverse direc- tions may need to accommodate the negative moments. Compared to those in the traditional system, the longitu- dinal nominal stress at middle span increases a lot in the new deck system and the effective flange width varies significantly. In addition, the dynamic results show that the impact factor is influenced by the spacing of connections. Finally, some design concerns of the new deck system are proposed.
文摘Construction of forestry socialized service systems is the important content for reform of collective forestry tenure systems.Based on the necessity,possibility and problem of construction of forestry socialized service system,according to Barnard's Organizational Structure theory,the path and countermeasure of forestry socialized service system in China are discussed.
文摘This paper compares the satisfaction of users of residential buildings produced by two construction processes considered as industrialized:“prefabricated masonry panels”and“reinforced concrete walls molded on site”and compared with“conventional process”(structural masonry of concrete blocks).The premise of the study was to diagnose the level of acceptance of the buildings considered industrialized by the Brazilian population,aiming to assess whether the preference for the systems considered“conventional”and the rejection of the“industrialized”is decreasing in Brazil.This article concerns the results obtained in the second phase of the research,which was carried out after five years of the first phase.So,if the buildings were considered new in the first phase,this second research was carried out after the depreciation due to the action of time.To quantify the“degree of satisfaction”the same checklist of the first survey was applied,in the same neighborhood and the sum attributed to each answer made by residents was applied and,as a result,it was possible to ascertain the oscillations in it and to confirm the satisfactory acceptance of industrialized construction systems and a tendency to reduce rejection by the population in relation to the innovative construction systems.
基金The project supported by National Natural Science Foundation Committeethrough Nankai Institute of Mathematics
文摘An isospectral problem with four potentials is discussed. The corresponding hierarchy of nonlinearevolution equations is derived. It is shown that the AKNS, Levi, D-AKNS hierarchies and a new oneare reductions of the above hierarchy. In each case the relevant Hamiltonian form is established bymaking use of the trase identity.
基金financial support from the National Natural Science Foundation of China(21531001 and 21421005).
文摘The application of metal-organic molecular hosts as“molecular flasks”has precipitated a surge of interest in the reactivity and properties of molecules within well-defined spaces.Here we report an approach to construct supramolecular systems for photo-catalytic hydrogen production and carbon dioxide reduction by encapsulating an organic dye molecule into the pocket of the redox-active metal-organic macrocycle.The assembled Ni_(3)L_(3)tricycle consists of three ligands and three nickel ions that alternately connect together.The special geometry enforces the distortion of the square planar coordinated configuration,and the coordination of the sulphur atoms enables the modification of redox potentials suitable for proton reduction and carbon dioxide reduction.The supramolecular systems that have fluorescein molecules being encapsulated as the photosensitive vips feature efficient activity for the photocatalytic carbon dioxide conversion and production reduction.The new reaction pathways within the confined space demonstrate the power of the supramolecular system over related systems.
基金supported by the Opening Project of Hubei Key Laboratory of Wudang Local Chinese Medicine Research(Hubei University of Medicine)(WDCM2023008)the Open Fund of Fujian Provincial Key Laboratory of Eco-Industrial Green Technology(WYKF-EIGT2022-4)+1 种基金the Opening Project of Structural Optimization and Application of Functional Molecules Key Laboratory of Sichuan Province(2023GNFZ-04)The authors would like to thank Xie Han from Shiyanjia Lab(www.shiyanjia.com)for theXPS tests.
文摘Constructing efficient coupling systems based on the hydrogen evolution reaction(HER)and the sulfion oxidation reaction(SOR)to realize low-cost hydrogen production could promote the rapid development of the hydrogen economy.However,sulfion is prone to poisoning the active site,leading to a decline in catalytic activity and inferior catalytic stability.Therefore,designing efficient and stable catalysts for the SOR and exploring the inherent reaction mechanism are still formidable challenges.Herein,nickel foam-supporting Mo-doped Co_(3)S_(4) nanosheet arrays(Mo-Co-S/NF)are synthesized and exhibit robust SOR catalytic activity and high long-term durability.The doped Mo species greatly improves the electronic structure of active sites and then enhances the intrinsic activity of the SOR.Mo-Co-S/NF only requires an ultra-low potential of 0.294 V vs.RHE to achieve a current density of 100 mA cm^(-2),which is significantly lower than that for the corresponding oxygen evolution reaction(OER,1.610 V vs.RHE).What's more,Mo-Co-S/NF is further used to construct an asymmetric acid-base coupling electrolyzer based on the HER-SOR,which achieves simultaneous hydrogen and sulfur production with ultra-low energy consumption and can even generate extra electric energy at a low current density.This work provides unique insights into the design of SOR electrocatalysts and dissymmetrical electrolytes,providing more possibilities for green and low-cost hydrogen production.
