After the success of the Daya Bay experiment, the Jiangmen Underground Neutrino Observatory （JUNO） was launched to measure neutrino-mass hierarchy and oscillation parameters and to study other neutrino physics. Its ...After the success of the Daya Bay experiment, the Jiangmen Underground Neutrino Observatory （JUNO） was launched to measure neutrino-mass hierarchy and oscillation parameters and to study other neutrino physics. Its central detector is set for antineutrinos from reactors, the Earth, the atmosphere, and the Sun. The main requirements of the central detector are con- tainment of 20 kt of liquid scintillator, as the target mass, and 3% energy resolution. It is about a ball-shape detector of 38.5 m with -75% coverage of PMT on its inner surface. The design of such a huge detector is a big challenge because it must meet the requirements for several different types of physics measurement and possess the feasibility and reliability in its structure and engineering, all at reasonable time and cost. One option for the JUNO central detector is a hyper-scale acrylic ball sub- merged in the water to shield the background. This paper proposes a structural scheme for such an acrylic ball that is supported by a stainless-steel truss, inspired by point-supported glass-curtain walls in civil engineering. The preliminary design of the scheme is completed and verified by finite element （FE） method using ABAQUS. FE analysis shows that the scheme can con- trol the stress level of the acrylic ball within the limit of 5 to 10 MPa, in accordance with the demand of the design objective of the central detector. The scheme is of outstanding global stability and allows various chocces on local connections. We prove that the scheme is of good feasibility and should be a reasonable option for the central detector.展开更多
The stretch bending of L-section variable-curvature SUS301L stainless-steel roof bending beams for metro vehicles was numerically simulated.The causes of defects such as wrinkling,section distortion,and poor contour a...The stretch bending of L-section variable-curvature SUS301L stainless-steel roof bending beams for metro vehicles was numerically simulated.The causes of defects such as wrinkling,section distortion,and poor contour accuracy were analysed,and the corresponding control methods were proposed.The simulation results demonstrated that wrinkling in the small-arc segment could be eliminated by setting the die clearance and adjusting the elongation reasonably.Owing to the sidewall shrinkage of the profile in the process of stretch bending,the die groove depth was correspondingly reduced.Each section of the profile was effectively supported by the bottom of the die groove,and the section distortion could be controlled.Springback was the main reason for the poor contour accuracy,which could be compensated by modifying the die surface based on the springback value.Using the above defect control methods,forming experiments were performed on a new type of stretch bending die with variable die clearance and groove depth developed in this work.Finally,high-quality components were obtained,which verified the efficacy of the defect control methods.展开更多
Duplex stainless steels are being used on applications that require,especially,high corrosion resistance and overall good mechanical properties,such as the naval and oil-gas exploration industry.The components employe...Duplex stainless steels are being used on applications that require,especially,high corrosion resistance and overall good mechanical properties,such as the naval and oil-gas exploration industry.The components employed in these industries are usually obtained by machining,however,these alloys have low machinability when compared to conventional stainless steels.In this work,a study of the wear developed when milling duplex stainless-steel,LDX 2101,is going to be presented and evaluated,employing four types of milling tools with different geometries and coatings,while studying the influence of feed rate and cutting length in the wear of these tools.Tools used have been provided with two and four flutes,as well as three different coatings,namely:TiAlN,TiAlSiN and AlCrN.The cutting behavior of these tools was analyzed;data relative to the cutting forces developed during the process were obtained;and roughness measurements of the machined surfaces were executed.The tools were then submitted to scanning electron microscope(SEM)analysis,enabling the identification of the wear mechanisms that tools were subjected to when machining this material,furthermore,the early stages of these mechanisms were also identified.All this work was done with the goal of relating the machining parameters and cutting force values obtained,identifying,and discussing the wear patterns that were observed in the coating and tools after the milling tests,providing further information on the machining of these alloys.展开更多
A simulation-driven design method which uses multiple optimization methods can effectively promote innovative structural design tion analysis can enormously improve the efficiency of modelling and solving.This study e...A simulation-driven design method which uses multiple optimization methods can effectively promote innovative structural design tion analysis can enormously improve the efficiency of modelling and solving.This study establishes a general workflow of structural and reduce the product development cycle.Meanwhile,the sub-model technology which has more detailed simulation and optimizaoptimization for a stainless-steel metro bolster by combining the simulation-driven design method and sub-model technology.In the sub-model definition phase,the end underframe sub-model which contains the bolster is obtained based on the whole car body finite element(FE)model,and the effectiveness of the end underframe sub-model is also proved.In the conceptual design phase,the is determined according to manufacturing processes and design experiences.In the detailed design phase,the thickness of each topology path inside the bolster is obtained by the topology method and the optimized structure of the inner ribs inside the bolster part of the bolster is determined by size optimization.The simulation analyses indicate that the requirements of static strength and can be decreased by 17.79% compared with the original bolster structure,which means that not only the lightweight design goal fatigue strength are fulfilled by the optimized bolster structure.Besides,the weight can be reduced by 11.18% and the weld length is achicved.but also the welding auantity and manufacturing difficulty are geatly reduced.The results show the effectiveness of the simulation-driven design method based on the sub-model technology in the structural optimization for key parts of rail transit vehicles.展开更多
In order to enhance the ablation-resistant performance of stainless-steel conductive rails,Mo coating,410 stainless steel coating and 15 wt%Cr_(2)AlIC particles reinforced 410 stainless steel composite coating were pr...In order to enhance the ablation-resistant performance of stainless-steel conductive rails,Mo coating,410 stainless steel coating and 15 wt%Cr_(2)AlIC particles reinforced 410 stainless steel composite coating were prepared and evaluated.Different from the weak interfacial strength caused by the dissimilar metals between Mo and steel rails,410 stainless steel coating has better interfacial contact with steel rails.The introduction of Cr_(2)AlC into 410 stainless steels further strengthened the mechanical properties of coating by alloy strengthening effect and particle strengthening effect,as the decomposition of Cr_(2)AlC into nano CrC particles is accompanied with the diffusion of Al atoms into 410 stainless steels.It was found that the composite coating can still resist arc erosion at 150 A current,as a dense oxide film formed during the ablation process and the decomposition of Cr_(2)AlC contributed to the heat absorption.展开更多
A novel buckling-induced forming method is proposed to produce metal bellows.The tube billet is firstly treated by local heating and cooling,and the axial loading is applied on both ends of the tube,then the buckling ...A novel buckling-induced forming method is proposed to produce metal bellows.The tube billet is firstly treated by local heating and cooling,and the axial loading is applied on both ends of the tube,then the buckling occurs at the designated position and forms a convolution.In this paper,a forming apparatus is designed and developed to produce both discontinuous and continuous bellows of 304 stainless steel,and their characteristics are discussed respectively.Furthermore,the influences of process parameters and geometric parameters on the final convolution profile are deeply studied based on FEM analysis.The results suggest that the steel bellows fabricated by the presented buckling-induced forming method have a uniform shape and no obvious reduction of wall thickness.Meanwhile,the forming force required in the process is quite small.展开更多
In the present paper,46 cases of periarthritis of shoulder were treated by needlingthe Jiansanzhen with magnetic pole needle and massage. Among them,43 cases were cured, ac-counting for 93. 48% and 46 were effective. ...In the present paper,46 cases of periarthritis of shoulder were treated by needlingthe Jiansanzhen with magnetic pole needle and massage. Among them,43 cases were cured, ac-counting for 93. 48% and 46 were effective. The total effective rate was 100%. In control groupI there were 23 cases, who received treatment of acupuncture with traditional stainless-steel fili-form needle and massage, the total effective rate was 91. 3%. Comparison of the therapeutic ef-fects between the two groups showed X^2=4. 12, P【0.05. In control group II there were 23 cas-es, who received needling Tiaokou point (ST 38)-through-Chengshan (BL 57) with the abovementioned stainless-steel filiform, one of ancient and modern experimental methods, the total ef-fecive rate was 82. 6%, which was compared with that in the treatment group, indicating X^2=8.492, P【0. 01. It is suggested that the therapeutic effect in the treatment group was superior tothat in the control group I and significantly superior to that in the control group II.展开更多
Differential scanning calorimetry (DSC) provides easy screening for thermal hazard evaluation. Here, we investigate the difference between using glass and stainless-steel vessels on the DSC measurement of exothermic d...Differential scanning calorimetry (DSC) provides easy screening for thermal hazard evaluation. Here, we investigate the difference between using glass and stainless-steel vessels on the DSC measurement of exothermic decomposition energy (QDSC) for 41 chemical substances (containing nitro, halogen, peroxide, and sulfur groups, and hydrazine bonds). Two borosilicate glass vessels (capillary and ampule) and one stainless-steel vessel were used. All QDSC values obtained were investigated with reference to the permissible fluctuation range specified by the ASTM (American Society for Testing and Materials) international Both glass vessels produced very similar QDSC values, despite different sample scales. The QDSC values obtained with the glass vessels were generally roughly within the variation tolerance range of the stainless-steel vessel. Notable exceptions were halogen- or sulfur-containing compounds;these exhibited smaller QDSC values with glass vessels in almost all cases. We will investigate whether certain structures in compounds react with stainless steel. The vessel material choice is crucial in evaluating the true reactivity of a substance.展开更多
Spectrally selective glazing system attracts great attention for energy efficient radiator applications. The present work reports the possibility of a specific shield (Stainless steel/Borosilicate glass) to provide pa...Spectrally selective glazing system attracts great attention for energy efficient radiator applications. The present work reports the possibility of a specific shield (Stainless steel/Borosilicate glass) to provide passive cooling for the purpose of reducing the use of classical active method. Radiative cooling devices require a convective shield that blocks all incoming solar radiation, but should selectively reemit radiation in the “atmospheric-window” region. In this study, borosilicate glass substrate coated with a stainless steel thin film was prepared by thermal evaporation and low pressure (6.3 × 10<sup>-3</sup> bar) DC plasma sputtering, in order to achieve the radiative cooling effect. The optical properties of the optimal thickness thin film were measured in the wavelength range of 0.3-20 μm by an OL-750 double-beam spectroradiometer. The thin film has high visible band reflectance with high infrared band emissivity across the full 8-13 μm;which indicates that stainless steel thin film can be used as good radiative cooling material.展开更多
The ability to regulate and apply surface wettability has attracted much attention in the surface engineering field.In this study,a simple chemical etching method was used to construct a rough micro/nano structure on ...The ability to regulate and apply surface wettability has attracted much attention in the surface engineering field.In this study,a simple chemical etching method was used to construct a rough micro/nano structure on 304 stainless steel mesh;this rough surface was subsequently decorated with fatty acids of varying chain length to regulate wettability.The wettability,composition,and morphology of the surface were characterized and ana-lyzed by measuring contact angles,and by atomic force microscopy,scanning electron microscopy,and Fourier-transform infrared spectroscopy.The superhydrophobic and superoleophilic properties of the mesh modified with long-chain fatty acids were examined for oil-water separation performance and reusability.The surface had a micro/nano hierarchical morphology with ordered carbon chains,and the hydrophilic-to-superhydrophobic transformation was achieved by adjusting the chain length of the fatty acid to deliver contact angles in the range of 30°~154°.The oil contact angle was always 0°,irrespective of the chain length fatty acid,and oil drops quickly penetrated the mesh surface.A fatty acid with a longer chain afforded a more hydrophobic and oleophilic mesh surface and better oil-water separation efficiency(up to 96%),which still exceeded 85%after 50 cycles of oil-water separation testing.Consequently,the prepared surface with controllable wettability has excellent prospects for use in intelligent response interfaces and oil-water separation applications.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA10010200)the Tsinghua University Initiative Scientific Research Program(Grant No.20131089288)
文摘After the success of the Daya Bay experiment, the Jiangmen Underground Neutrino Observatory （JUNO） was launched to measure neutrino-mass hierarchy and oscillation parameters and to study other neutrino physics. Its central detector is set for antineutrinos from reactors, the Earth, the atmosphere, and the Sun. The main requirements of the central detector are con- tainment of 20 kt of liquid scintillator, as the target mass, and 3% energy resolution. It is about a ball-shape detector of 38.5 m with -75% coverage of PMT on its inner surface. The design of such a huge detector is a big challenge because it must meet the requirements for several different types of physics measurement and possess the feasibility and reliability in its structure and engineering, all at reasonable time and cost. One option for the JUNO central detector is a hyper-scale acrylic ball sub- merged in the water to shield the background. This paper proposes a structural scheme for such an acrylic ball that is supported by a stainless-steel truss, inspired by point-supported glass-curtain walls in civil engineering. The preliminary design of the scheme is completed and verified by finite element （FE） method using ABAQUS. FE analysis shows that the scheme can con- trol the stress level of the acrylic ball within the limit of 5 to 10 MPa, in accordance with the demand of the design objective of the central detector. The scheme is of outstanding global stability and allows various chocces on local connections. We prove that the scheme is of good feasibility and should be a reasonable option for the central detector.
基金the National Natural Science Foundation of China(51101072)Technology Development Program of Jilin Province(20150307015GX and 20160204058GX).
文摘The stretch bending of L-section variable-curvature SUS301L stainless-steel roof bending beams for metro vehicles was numerically simulated.The causes of defects such as wrinkling,section distortion,and poor contour accuracy were analysed,and the corresponding control methods were proposed.The simulation results demonstrated that wrinkling in the small-arc segment could be eliminated by setting the die clearance and adjusting the elongation reasonably.Owing to the sidewall shrinkage of the profile in the process of stretch bending,the die groove depth was correspondingly reduced.Each section of the profile was effectively supported by the bottom of the die groove,and the section distortion could be controlled.Springback was the main reason for the poor contour accuracy,which could be compensated by modifying the die surface based on the springback value.Using the above defect control methods,forming experiments were performed on a new type of stretch bending die with variable die clearance and groove depth developed in this work.Finally,high-quality components were obtained,which verified the efficacy of the defect control methods.
基金The present work was done and funded under the scope of the project ON-SURF(ANI|P2020|POCI-01-0247-FEDER-024521,co-funded by Portugal 2020 and FEDER,through COMPETE 2020-Operational Programme for Competitiveness and Internationalisation.
文摘Duplex stainless steels are being used on applications that require,especially,high corrosion resistance and overall good mechanical properties,such as the naval and oil-gas exploration industry.The components employed in these industries are usually obtained by machining,however,these alloys have low machinability when compared to conventional stainless steels.In this work,a study of the wear developed when milling duplex stainless-steel,LDX 2101,is going to be presented and evaluated,employing four types of milling tools with different geometries and coatings,while studying the influence of feed rate and cutting length in the wear of these tools.Tools used have been provided with two and four flutes,as well as three different coatings,namely:TiAlN,TiAlSiN and AlCrN.The cutting behavior of these tools was analyzed;data relative to the cutting forces developed during the process were obtained;and roughness measurements of the machined surfaces were executed.The tools were then submitted to scanning electron microscope(SEM)analysis,enabling the identification of the wear mechanisms that tools were subjected to when machining this material,furthermore,the early stages of these mechanisms were also identified.All this work was done with the goal of relating the machining parameters and cutting force values obtained,identifying,and discussing the wear patterns that were observed in the coating and tools after the milling tests,providing further information on the machining of these alloys.
基金supported by the Science and Technology Research and Development Program of CRRC Cor por ation Limited(Gr ant No.2021CKB030)the Science and Technology Major Project of CRRC Corporation Limited(Grant No.2021CKZ008-3).
文摘A simulation-driven design method which uses multiple optimization methods can effectively promote innovative structural design tion analysis can enormously improve the efficiency of modelling and solving.This study establishes a general workflow of structural and reduce the product development cycle.Meanwhile,the sub-model technology which has more detailed simulation and optimizaoptimization for a stainless-steel metro bolster by combining the simulation-driven design method and sub-model technology.In the sub-model definition phase,the end underframe sub-model which contains the bolster is obtained based on the whole car body finite element(FE)model,and the effectiveness of the end underframe sub-model is also proved.In the conceptual design phase,the is determined according to manufacturing processes and design experiences.In the detailed design phase,the thickness of each topology path inside the bolster is obtained by the topology method and the optimized structure of the inner ribs inside the bolster part of the bolster is determined by size optimization.The simulation analyses indicate that the requirements of static strength and can be decreased by 17.79% compared with the original bolster structure,which means that not only the lightweight design goal fatigue strength are fulfilled by the optimized bolster structure.Besides,the weight can be reduced by 11.18% and the weld length is achicved.but also the welding auantity and manufacturing difficulty are geatly reduced.The results show the effectiveness of the simulation-driven design method based on the sub-model technology in the structural optimization for key parts of rail transit vehicles.
基金supported by Beijing Natural Science Foundation(3232011)the Pre-Research Program in National 14th Five-Year Plan(80923010304)the National Natural Science Foundation of China(52130509).
文摘In order to enhance the ablation-resistant performance of stainless-steel conductive rails,Mo coating,410 stainless steel coating and 15 wt%Cr_(2)AlIC particles reinforced 410 stainless steel composite coating were prepared and evaluated.Different from the weak interfacial strength caused by the dissimilar metals between Mo and steel rails,410 stainless steel coating has better interfacial contact with steel rails.The introduction of Cr_(2)AlC into 410 stainless steels further strengthened the mechanical properties of coating by alloy strengthening effect and particle strengthening effect,as the decomposition of Cr_(2)AlC into nano CrC particles is accompanied with the diffusion of Al atoms into 410 stainless steels.It was found that the composite coating can still resist arc erosion at 150 A current,as a dense oxide film formed during the ablation process and the decomposition of Cr_(2)AlC contributed to the heat absorption.
基金National Natural Science Foundation of China(Grant No.52175349)Aeronautical Science Foundation of China(Grant No.20200009057004)。
文摘A novel buckling-induced forming method is proposed to produce metal bellows.The tube billet is firstly treated by local heating and cooling,and the axial loading is applied on both ends of the tube,then the buckling occurs at the designated position and forms a convolution.In this paper,a forming apparatus is designed and developed to produce both discontinuous and continuous bellows of 304 stainless steel,and their characteristics are discussed respectively.Furthermore,the influences of process parameters and geometric parameters on the final convolution profile are deeply studied based on FEM analysis.The results suggest that the steel bellows fabricated by the presented buckling-induced forming method have a uniform shape and no obvious reduction of wall thickness.Meanwhile,the forming force required in the process is quite small.
文摘In the present paper,46 cases of periarthritis of shoulder were treated by needlingthe Jiansanzhen with magnetic pole needle and massage. Among them,43 cases were cured, ac-counting for 93. 48% and 46 were effective. The total effective rate was 100%. In control groupI there were 23 cases, who received treatment of acupuncture with traditional stainless-steel fili-form needle and massage, the total effective rate was 91. 3%. Comparison of the therapeutic ef-fects between the two groups showed X^2=4. 12, P【0.05. In control group II there were 23 cas-es, who received needling Tiaokou point (ST 38)-through-Chengshan (BL 57) with the abovementioned stainless-steel filiform, one of ancient and modern experimental methods, the total ef-fecive rate was 82. 6%, which was compared with that in the treatment group, indicating X^2=8.492, P【0. 01. It is suggested that the therapeutic effect in the treatment group was superior tothat in the control group I and significantly superior to that in the control group II.
文摘Differential scanning calorimetry (DSC) provides easy screening for thermal hazard evaluation. Here, we investigate the difference between using glass and stainless-steel vessels on the DSC measurement of exothermic decomposition energy (QDSC) for 41 chemical substances (containing nitro, halogen, peroxide, and sulfur groups, and hydrazine bonds). Two borosilicate glass vessels (capillary and ampule) and one stainless-steel vessel were used. All QDSC values obtained were investigated with reference to the permissible fluctuation range specified by the ASTM (American Society for Testing and Materials) international Both glass vessels produced very similar QDSC values, despite different sample scales. The QDSC values obtained with the glass vessels were generally roughly within the variation tolerance range of the stainless-steel vessel. Notable exceptions were halogen- or sulfur-containing compounds;these exhibited smaller QDSC values with glass vessels in almost all cases. We will investigate whether certain structures in compounds react with stainless steel. The vessel material choice is crucial in evaluating the true reactivity of a substance.
文摘Spectrally selective glazing system attracts great attention for energy efficient radiator applications. The present work reports the possibility of a specific shield (Stainless steel/Borosilicate glass) to provide passive cooling for the purpose of reducing the use of classical active method. Radiative cooling devices require a convective shield that blocks all incoming solar radiation, but should selectively reemit radiation in the “atmospheric-window” region. In this study, borosilicate glass substrate coated with a stainless steel thin film was prepared by thermal evaporation and low pressure (6.3 × 10<sup>-3</sup> bar) DC plasma sputtering, in order to achieve the radiative cooling effect. The optical properties of the optimal thickness thin film were measured in the wavelength range of 0.3-20 μm by an OL-750 double-beam spectroradiometer. The thin film has high visible band reflectance with high infrared band emissivity across the full 8-13 μm;which indicates that stainless steel thin film can be used as good radiative cooling material.
基金the National Natural Science Foundation of China(Grant No.51875299).
文摘The ability to regulate and apply surface wettability has attracted much attention in the surface engineering field.In this study,a simple chemical etching method was used to construct a rough micro/nano structure on 304 stainless steel mesh;this rough surface was subsequently decorated with fatty acids of varying chain length to regulate wettability.The wettability,composition,and morphology of the surface were characterized and ana-lyzed by measuring contact angles,and by atomic force microscopy,scanning electron microscopy,and Fourier-transform infrared spectroscopy.The superhydrophobic and superoleophilic properties of the mesh modified with long-chain fatty acids were examined for oil-water separation performance and reusability.The surface had a micro/nano hierarchical morphology with ordered carbon chains,and the hydrophilic-to-superhydrophobic transformation was achieved by adjusting the chain length of the fatty acid to deliver contact angles in the range of 30°~154°.The oil contact angle was always 0°,irrespective of the chain length fatty acid,and oil drops quickly penetrated the mesh surface.A fatty acid with a longer chain afforded a more hydrophobic and oleophilic mesh surface and better oil-water separation efficiency(up to 96%),which still exceeded 85%after 50 cycles of oil-water separation testing.Consequently,the prepared surface with controllable wettability has excellent prospects for use in intelligent response interfaces and oil-water separation applications.
