3D printing techniques offer an effective method in fabricating complex radially multi-material structures.However,it is challenging for complex and delicate radially multi-material model geometries without supporting...3D printing techniques offer an effective method in fabricating complex radially multi-material structures.However,it is challenging for complex and delicate radially multi-material model geometries without supporting structures,such as tissue vessels and tubular graft,among others.In this work,we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform.The 3D model fabrication is accomplished through line projection.The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume.By controlling the distance between the rod and the printing window,we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers.By controlling the width of fine slits at the printing window,we achieved the printing of structures with a minimum feature size of 10 micrometers.Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s.Additionally,it enables the printing of axial multi-material structures,thereby achieving adjustable mechanical strength.This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry,aerospace,and more.展开更多
A zinc（Ⅱ） compound [ZnCl2（mpcm）2]（1,mpcm = methyl-3-pyridylcarbamate） was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The c...A zinc（Ⅱ） compound [ZnCl2（mpcm）2]（1,mpcm = methyl-3-pyridylcarbamate） was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21/n,C14H16ZnCl2N4O4,Mr = 440.58,a = 8.7893（7）,b = 24.978（2）,c = 9.2510（8）,β = 109.318（1）°,V = 1916.6（3）3,Z = 4,θ = 1.63～25.20°,Dc = 1.527 g/cm3,μ = 1.585 mm-1,F（000） = 896,the final R = 0.0255 and wR = 0.0654 for 3080 observed reflections with Ⅰ 〉 2σ（Ⅰ）.The zinc atom is four-coordinated by the pyridyl groups of two mpcm ligands and two chloride ions with a tetrahedral geometry.Two [ZnCl2（mpcm）2] subunits are held together by a pair of hydrogen bonds,forming a 32-membered macrocyclic dimer,which is further extended into a 3D tubular structure via hydrogen bonding.展开更多
The development of microengineered hydrogels has opened up unlimited possibilities for designing complex structures at the microscale. In this study, we constructed an origami-inspired tubular structure with controlle...The development of microengineered hydrogels has opened up unlimited possibilities for designing complex structures at the microscale. In this study, we constructed an origami-inspired tubular structure with controlled mechanical buckling based on optically induced electrokinetics(OEK). By inducing a stress gradient in the thickness, a tubular structure can be formed from a poly(ethylene glycol) diacrylate(PEGDA) hydrogel film of various shapes that have been custom fabricated. To achieve an ideal three-dimensional(3D) structure, the amplitude of the tubular structure can be controlled by adjusting the aspect ratios or polymerization time. Furthermore, the tubular structure can be manipulated for the collection and transportation of microspheres.In summary, we provide an effective method for designing 3D structures at the micro-nano scale. This forming method holds great potential for achieving various functions in tissue engineering, drug packaging, and transportation in the future.展开更多
This paper deals with the issues involved during the design of a complex gymnasium located at the new campus of Zhejiang University. The complexity comes from the gymnasium’s being of three parts: long-span membrane ...This paper deals with the issues involved during the design of a complex gymnasium located at the new campus of Zhejiang University. The complexity comes from the gymnasium’s being of three parts: long-span membrane structure, prestressed concrete structure and extraordinarily long tubular steel structure without seams. The paper first presents considera- tions of the prestress design, followed by analyses of the stress states due to temperature changes and concrete shrinkage. Buckling and postbuckling analyses were performed to determine the load-carrying capacity of the perfect and imperfect tubular steel structure of the inclined arch system, while dynamic relaxation method and general nonlinear finite element analysis were used to carry out shape-finding and stress analyses of the membrane structure respectively. Finally, collated monitoring date was applied to control the construction quality and verify the design parameters. Some useful conclusions are available at the end of the paper.展开更多
This paper introduces the influence factors of axial stiffness of tubular X-joints. The analysis model of tubular joints using plate and shell finite element method is also made. Systematic single-parameter analysis o...This paper introduces the influence factors of axial stiffness of tubular X-joints. The analysis model of tubular joints using plate and shell finite element method is also made. Systematic single-parameter analysis of tubular X-joints is performed using Ansys program. The influences of those factors, including ratio of brace diameter to chord diameter （β）, ratio of chord diameter to twice chord thickness （γ）, ratio of brace wall thickness to that of chord （τ）, brace-to-chord intersection angle （θ）, and chord stress ratio, ratio of another brace diameter to chord diameter, in-plane and out-of-plane moment of braces, etc., on stiffness of tubular X-joints are analyzed. Two non-dimensional parameters-joint axial stiffness factor ηN and axial force capacity factor ωN are proposed, and the relationship curve of the two factors is determined. Computational formulas of tubular X-joint axial stiffness are obtained by multi-element regression technology. The formulas can be used in design and analysis of steel tubular structures.展开更多
An important consideration when using hot-dip galvanized tubular structures is the uncertainty of the joint behaviour due to the possible reduction in the global joint resistance produced by the vent holes required fo...An important consideration when using hot-dip galvanized tubular structures is the uncertainty of the joint behaviour due to the possible reduction in the global joint resistance produced by the vent holes required for the galvanizing process. This paper assesses the effect on the joint strength of the angle between the brace members and the chord in a K- or N-joints made with rectangular hollow sections. The study is focused on the case when those brace members include characteristic holes required for the hot-dip galvanizing process. To accomplish the objective of the proposed work, some tests on full-scale K- and N-joints, including angles of 35°, 45°, 55° and 90°, were carried out. The experimental work was complemented by a validated numerical simulation in order to give some design recommendations and to extend the research to other joint configurations.展开更多
It is a prospective strategy to produce sustainable energy by photocatalytic overall water splitting(POWS).This work aims to develop a simple method for integrating a donor-acceptor system into polymeric car-bon nitri...It is a prospective strategy to produce sustainable energy by photocatalytic overall water splitting(POWS).This work aims to develop a simple method for integrating a donor-acceptor system into polymeric car-bon nitride(PCN)structure,which could accelerate the charge separation significantly.In the as-prepared photocatalyst(COCNT),carbon and oxygen were successfully incorporated into the framework of PCN,and the chemical environment of C and O was well probed by X-ray absorption near-edge structure(XANES)and X-ray photoelectron spectroscopy(XPS).It showed that the C-containing and O-containing segments of COCNT played the role of a donor,while the heptazine part played the role of an acceptor.In addition,Density-functional-theory(DFT)calculations confirmed the spatial split of the highest occupied molec-ular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)for promoting charge separation.Impressively,COCNT could efficiently split pure water to generate hydrogen and oxygen.And,the photo-catalytic hydrogen evolution rate over COCNT(1550.9μmol g^(-1)h^(-1))is about 17-fold higher than that of PCN.Finally,we proposed a possible photocatalytic mechanism to explain the above results.展开更多
The one plus one (1 + 1) mode of hydrosilation reaction of ladderlike cis-isotatic polyallylsilsesquioxane (Allyl-T) and polyhydrosilsesquioxane (H-T) using dicyclopentadienylplatinumdichloride (Cp2PtCl2) as the catal...The one plus one (1 + 1) mode of hydrosilation reaction of ladderlike cis-isotatic polyallylsilsesquioxane (Allyl-T) and polyhydrosilsesquioxane (H-T) using dicyclopentadienylplatinumdichloride (Cp2PtCl2) as the catalyst leads to the formation of a new polyorganosiloxane (POS). The presence of nanoscale tubular structure in the product POS was preliminarily proved by IR, H-1-NMR, differential scanning calorimetry (DSC), X-ray diffraction (XRD), gel permeation chromatography (GPC), atomic force microscopy (AFM) and molecular simulation.展开更多
The hydrosilylation reaction of ladderlike polyvinylsilsesquioxane (Vi-T) with 1, 1, 3, 3-tetramethyldisiloxane (H-MM) catalyzed by dicyclopentadienyl-dichloroplatinium (Cp2PtCl2) was carried out well in tetrahydrofur...The hydrosilylation reaction of ladderlike polyvinylsilsesquioxane (Vi-T) with 1, 1, 3, 3-tetramethyldisiloxane (H-MM) catalyzed by dicyclopentadienyl-dichloroplatinium (Cp2PtCl2) was carried out well in tetrahydrofuran (THF) to produce a soluble white solid. This product was characterized by IR, H-1-NMR, C-13-NMR, Si-29-NMR, DSC, X-ray diffraction method, gel permeation chromatography (GPC), vapour pressure osmometry (VPO), atomic force microscopy (AFM) and molecular simulation. These results prove that the product contains nanoscale tubular structure.展开更多
Shear-extrusion process and its forming parameters are proposed, whilst its laborsaving characteristic is utilized to forge large-size shutoff valve bodies on the middle-due press. This new process is intended for the...Shear-extrusion process and its forming parameters are proposed, whilst its laborsaving characteristic is utilized to forge large-size shutoff valve bodies on the middle-due press. This new process is intended for the manufacture of large-size forged tubular components with branches on the middle-due press. Experiments are carried out and processing parameters are obtained regarding the shear- extrusion process of a large-size shutoff valve body. Deformation and metal flow in the shear- extrusion process are investigated. In order to verify the laborsaving characteristic of this new process, some contrast experiments of extrusion force are performed between shear-extrusion and upsetting-extrusion for forming tubular components with branches. Based on rigid-plastic FEM, a plane-strain model is established to analyze shear-extrusion process of tubular components with branches. The analysis results by 2-dimensions FEM are comparatively well consistent with experimental results. Both simulated and experimental results show that this new forming process is feasible for forging large-size tubular components with branches on the middle-due press.展开更多
Polymerization is a valid strategy to solve the dissolution issue of organic electrode materials in aprotic electrolytes.However,conventional polymers usually with amorphous structures and morphology’s influence on e...Polymerization is a valid strategy to solve the dissolution issue of organic electrode materials in aprotic electrolytes.However,conventional polymers usually with amorphous structures and morphology’s influence on electrochemistry have rarely been studied.Herein,a hollow tubular poly phenyl pyrene-4,5,9,10-tetraone(T-PPh-PTO)organic cathode material was designed and synthesized based on the concentration-gradient of the precursor(PTO-Br2)and asymmetrical internal diffusion during the reaction.The unique hollow structure endowed T-PPh-PTO with a short Li+diffusion path accompanied by a high diffusion Li+coefficient(D≈10−8 cm^(2)·s^(−1)).Thus,T-PPh-PTO presented a capacitance-dominated redox pseudocapacitance action with an outstanding rate performance(173 mAh·g^(−1)at 2 A·g^(−1))and high cycle stability(capacity retention ratio is 91.7%after 2,000 cycles).Our study leads to further developments in designing unique organic structures for energy storage.展开更多
This work presents a brief review of our recent research on an antiresonant mechanism named core antiresonant reflection(CARR),which leads to a broadband terahertz(THz)spectrum output with periodic dips at resonant fr...This work presents a brief review of our recent research on an antiresonant mechanism named core antiresonant reflection(CARR),which leads to a broadband terahertz(THz)spectrum output with periodic dips at resonant frequencies after its transmission along a hollow-core tubular structure(e.g.,a paper tube).The CARR theory relies only on parameters of the tube core(e.g.,the inner diameter)rather than the cladding,thus being distinct from existing principles such as the traditional antiresonant reflection inside optical waveguides(ARROWs).We demonstrate that diverse tubular structures,including cylindrical,polyhedral,spiral,meshy,and notched hollow tubes with either transparent or opaque cladding materials,as well as a thick-walled hole,could indeed become CARR-type resonators.Based on this CARR effect,we also perform various applications,such as pressure sensing with paper-folded THz cavities,force/magnetism-driven chiral polarization modulations,and single-pulse measurements of the angular dispersion of THz beams.In future studies,the proposed CARR method promises to support breakthroughs in multiple fields by means of being extended to more kinds of tubular entities for enhancing their interactions with light waves in an antiresonance manner.展开更多
基金supported financially by the Fundamental Research Funds for the Central Universities (YWF-22-K-101,YWF-23-L-805 and YWF-23-YG-QB-006)the support from the National Natural Science Foundation of China (12372106)Fundamental Research Funds for the Central Universities
文摘3D printing techniques offer an effective method in fabricating complex radially multi-material structures.However,it is challenging for complex and delicate radially multi-material model geometries without supporting structures,such as tissue vessels and tubular graft,among others.In this work,we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform.The 3D model fabrication is accomplished through line projection.The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume.By controlling the distance between the rod and the printing window,we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers.By controlling the width of fine slits at the printing window,we achieved the printing of structures with a minimum feature size of 10 micrometers.Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s.Additionally,it enables the printing of axial multi-material structures,thereby achieving adjustable mechanical strength.This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry,aerospace,and more.
基金Supported by the National Natural Science Foundation of China (No. 20872149)
文摘A zinc（Ⅱ） compound [ZnCl2（mpcm）2]（1,mpcm = methyl-3-pyridylcarbamate） was prepared by solvothermal reaction and characterized by elemental analysis,IR spectroscopy,TGA and single-crystal X-ray diffraction.The crystal is of monoclinic system,space group P21/n,C14H16ZnCl2N4O4,Mr = 440.58,a = 8.7893（7）,b = 24.978（2）,c = 9.2510（8）,β = 109.318（1）°,V = 1916.6（3）3,Z = 4,θ = 1.63～25.20°,Dc = 1.527 g/cm3,μ = 1.585 mm-1,F（000） = 896,the final R = 0.0255 and wR = 0.0654 for 3080 observed reflections with Ⅰ 〉 2σ（Ⅰ）.The zinc atom is four-coordinated by the pyridyl groups of two mpcm ligands and two chloride ions with a tetrahedral geometry.Two [ZnCl2（mpcm）2] subunits are held together by a pair of hydrogen bonds,forming a 32-membered macrocyclic dimer,which is further extended into a 3D tubular structure via hydrogen bonding.
基金supported by the National Natural Science Foundation of China(Grant No.62273289)the Youth Innovation Science and Technology Support Program of Shandong Province(Grant No.2022KJ274)。
文摘The development of microengineered hydrogels has opened up unlimited possibilities for designing complex structures at the microscale. In this study, we constructed an origami-inspired tubular structure with controlled mechanical buckling based on optically induced electrokinetics(OEK). By inducing a stress gradient in the thickness, a tubular structure can be formed from a poly(ethylene glycol) diacrylate(PEGDA) hydrogel film of various shapes that have been custom fabricated. To achieve an ideal three-dimensional(3D) structure, the amplitude of the tubular structure can be controlled by adjusting the aspect ratios or polymerization time. Furthermore, the tubular structure can be manipulated for the collection and transportation of microspheres.In summary, we provide an effective method for designing 3D structures at the micro-nano scale. This forming method holds great potential for achieving various functions in tissue engineering, drug packaging, and transportation in the future.
基金Project (No. 59908011) supported by the National Natural ScienceFoundation of China
文摘This paper deals with the issues involved during the design of a complex gymnasium located at the new campus of Zhejiang University. The complexity comes from the gymnasium’s being of three parts: long-span membrane structure, prestressed concrete structure and extraordinarily long tubular steel structure without seams. The paper first presents considera- tions of the prestress design, followed by analyses of the stress states due to temperature changes and concrete shrinkage. Buckling and postbuckling analyses were performed to determine the load-carrying capacity of the perfect and imperfect tubular steel structure of the inclined arch system, while dynamic relaxation method and general nonlinear finite element analysis were used to carry out shape-finding and stress analyses of the membrane structure respectively. Finally, collated monitoring date was applied to control the construction quality and verify the design parameters. Some useful conclusions are available at the end of the paper.
文摘This paper introduces the influence factors of axial stiffness of tubular X-joints. The analysis model of tubular joints using plate and shell finite element method is also made. Systematic single-parameter analysis of tubular X-joints is performed using Ansys program. The influences of those factors, including ratio of brace diameter to chord diameter （β）, ratio of chord diameter to twice chord thickness （γ）, ratio of brace wall thickness to that of chord （τ）, brace-to-chord intersection angle （θ）, and chord stress ratio, ratio of another brace diameter to chord diameter, in-plane and out-of-plane moment of braces, etc., on stiffness of tubular X-joints are analyzed. Two non-dimensional parameters-joint axial stiffness factor ηN and axial force capacity factor ωN are proposed, and the relationship curve of the two factors is determined. Computational formulas of tubular X-joint axial stiffness are obtained by multi-element regression technology. The formulas can be used in design and analysis of steel tubular structures.
文摘An important consideration when using hot-dip galvanized tubular structures is the uncertainty of the joint behaviour due to the possible reduction in the global joint resistance produced by the vent holes required for the galvanizing process. This paper assesses the effect on the joint strength of the angle between the brace members and the chord in a K- or N-joints made with rectangular hollow sections. The study is focused on the case when those brace members include characteristic holes required for the hot-dip galvanizing process. To accomplish the objective of the proposed work, some tests on full-scale K- and N-joints, including angles of 35°, 45°, 55° and 90°, were carried out. The experimental work was complemented by a validated numerical simulation in order to give some design recommendations and to extend the research to other joint configurations.
基金supported by the National Natural Science Foundation of China(No.51268054 and No.51468061)Natural Science Foundation of Tianjin,China(No.13JCQNJC07300)
基金supported by the National Natural Science Foundation of China(Nos.21703097 and 21972172)South-ern University of Science and Technology(SUSTech)start fund through the Shenzhen Peacock Talent program,the Shenzhen Ba-sic Research Fund project(No.JCYJ20150507170334573)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06N532).
文摘It is a prospective strategy to produce sustainable energy by photocatalytic overall water splitting(POWS).This work aims to develop a simple method for integrating a donor-acceptor system into polymeric car-bon nitride(PCN)structure,which could accelerate the charge separation significantly.In the as-prepared photocatalyst(COCNT),carbon and oxygen were successfully incorporated into the framework of PCN,and the chemical environment of C and O was well probed by X-ray absorption near-edge structure(XANES)and X-ray photoelectron spectroscopy(XPS).It showed that the C-containing and O-containing segments of COCNT played the role of a donor,while the heptazine part played the role of an acceptor.In addition,Density-functional-theory(DFT)calculations confirmed the spatial split of the highest occupied molec-ular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO)for promoting charge separation.Impressively,COCNT could efficiently split pure water to generate hydrogen and oxygen.And,the photo-catalytic hydrogen evolution rate over COCNT(1550.9μmol g^(-1)h^(-1))is about 17-fold higher than that of PCN.Finally,we proposed a possible photocatalytic mechanism to explain the above results.
基金This project was supported by the National Natural Science Foundation of China (No. 59483001).
文摘The one plus one (1 + 1) mode of hydrosilation reaction of ladderlike cis-isotatic polyallylsilsesquioxane (Allyl-T) and polyhydrosilsesquioxane (H-T) using dicyclopentadienylplatinumdichloride (Cp2PtCl2) as the catalyst leads to the formation of a new polyorganosiloxane (POS). The presence of nanoscale tubular structure in the product POS was preliminarily proved by IR, H-1-NMR, differential scanning calorimetry (DSC), X-ray diffraction (XRD), gel permeation chromatography (GPC), atomic force microscopy (AFM) and molecular simulation.
基金This project was supported by NSFC(59483001 & 29574187)& Chinese Academy of Sciences(KJ-952-S1-508)
文摘The hydrosilylation reaction of ladderlike polyvinylsilsesquioxane (Vi-T) with 1, 1, 3, 3-tetramethyldisiloxane (H-MM) catalyzed by dicyclopentadienyl-dichloroplatinium (Cp2PtCl2) was carried out well in tetrahydrofuran (THF) to produce a soluble white solid. This product was characterized by IR, H-1-NMR, C-13-NMR, Si-29-NMR, DSC, X-ray diffraction method, gel permeation chromatography (GPC), vapour pressure osmometry (VPO), atomic force microscopy (AFM) and molecular simulation. These results prove that the product contains nanoscale tubular structure.
文摘Shear-extrusion process and its forming parameters are proposed, whilst its laborsaving characteristic is utilized to forge large-size shutoff valve bodies on the middle-due press. This new process is intended for the manufacture of large-size forged tubular components with branches on the middle-due press. Experiments are carried out and processing parameters are obtained regarding the shear- extrusion process of a large-size shutoff valve body. Deformation and metal flow in the shear- extrusion process are investigated. In order to verify the laborsaving characteristic of this new process, some contrast experiments of extrusion force are performed between shear-extrusion and upsetting-extrusion for forming tubular components with branches. Based on rigid-plastic FEM, a plane-strain model is established to analyze shear-extrusion process of tubular components with branches. The analysis results by 2-dimensions FEM are comparatively well consistent with experimental results. Both simulated and experimental results show that this new forming process is feasible for forging large-size tubular components with branches on the middle-due press.
基金supported by the National Natural Science Foundation of China(Nos.51771094 and 21835004)the National Key Research and Development(R&D)Program of China(No.2016YFB0901500)+1 种基金the Ministry of Education of China(No.B12015)Tianjin Natural Science Foundation(No.18JCZDJC31500).
文摘Polymerization is a valid strategy to solve the dissolution issue of organic electrode materials in aprotic electrolytes.However,conventional polymers usually with amorphous structures and morphology’s influence on electrochemistry have rarely been studied.Herein,a hollow tubular poly phenyl pyrene-4,5,9,10-tetraone(T-PPh-PTO)organic cathode material was designed and synthesized based on the concentration-gradient of the precursor(PTO-Br2)and asymmetrical internal diffusion during the reaction.The unique hollow structure endowed T-PPh-PTO with a short Li+diffusion path accompanied by a high diffusion Li+coefficient(D≈10−8 cm^(2)·s^(−1)).Thus,T-PPh-PTO presented a capacitance-dominated redox pseudocapacitance action with an outstanding rate performance(173 mAh·g^(−1)at 2 A·g^(−1))and high cycle stability(capacity retention ratio is 91.7%after 2,000 cycles).Our study leads to further developments in designing unique organic structures for energy storage.
基金supported by the National Natural Science Foundation of China(Nos.61988102 and 62335012)the Youth Sci-Tech“Qimingxing”Program of Shanghai(No.22QC1400300)the National Key Research and Development Program of China(No.2022YFA1404004)。
文摘This work presents a brief review of our recent research on an antiresonant mechanism named core antiresonant reflection(CARR),which leads to a broadband terahertz(THz)spectrum output with periodic dips at resonant frequencies after its transmission along a hollow-core tubular structure(e.g.,a paper tube).The CARR theory relies only on parameters of the tube core(e.g.,the inner diameter)rather than the cladding,thus being distinct from existing principles such as the traditional antiresonant reflection inside optical waveguides(ARROWs).We demonstrate that diverse tubular structures,including cylindrical,polyhedral,spiral,meshy,and notched hollow tubes with either transparent or opaque cladding materials,as well as a thick-walled hole,could indeed become CARR-type resonators.Based on this CARR effect,we also perform various applications,such as pressure sensing with paper-folded THz cavities,force/magnetism-driven chiral polarization modulations,and single-pulse measurements of the angular dispersion of THz beams.In future studies,the proposed CARR method promises to support breakthroughs in multiple fields by means of being extended to more kinds of tubular entities for enhancing their interactions with light waves in an antiresonance manner.
