检索结果-南通市图书馆

Non-uniform shrinkage analysis of round billet using element-free Galerkin method

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2022年第1期29卷 80-87页

作者： Lai-qiang Cai xu-dong wang Man Yao School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) Dalian University of TechnologyDalian 116024LiaoningChina

An element-free Galerkin thermal–mechanical calculation model for the solidification and shrinkage of round billet was *** non-uniform heat flux measured in the plant trial was used as the boundary condition to simulate and analyze the deformation of solidified *** results indicate that the maximum and minimum shrinkages of the round billet at mold outlet are 0.78 and 0.21 mm,respectively,with apparent non-uniform *** local high-heat-flux region substantially dominates the non-uniformity of shell shrinkage,and the larger shrinkage usually derives from the high heat flux between the solidified shell and the mold in the circumferential ***,the shrinkage on the shell surface has an immediate connection with the equivalent ***,the shrinkage is more closely related to the radial stress component than the circumferential stress component.

关键词： Non-uniform shrinkage Round billet Element-free Galerkin method Thermal-mechanical model

Stochastic Resonance in a Bistable System with Time-Delayed Feedback Loops

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第8期50卷 396-402页

作者： LI dong-Xi xu Wei wang Liang xu Yong Department of Applied Mathematics Northwestern Polytechnical University Xi＇an 710072 China

The phenomenon of stochastic resonance of a bistable system subjected to linear time-delayed feedback loops driven by multiplieative Gaussian coloured noise and additive Gaussian white noise is investigated. Firstly, the analytic expression of the quasi-steady distribution function Ps （x, t） is derived by applying the unified coloured noise approximation and the Novikov Theorem; Secondly, the expression of the signal-to-noise ratio （SNR） is obtained in the adiabatic limit to quantify the stochastic resonance. Finally, tile effects of the linear coefficient a, the nonlinear coefficient b, the linear time-delayed feedback coefficient c and the delay time r on Ps（x,t） and SNR^± are discussed. It is found that the effects of the linear coefficient and the nonlinear coefficient, the positive linear time-delayed feedback coefficient and the negative linear time-delayed feedback coefficient, the positive delayed time and the negative delayed time on Ps（x,t） and SNR^± are different, respectively. This discussion would be helpful to the study of the system reliability and controlling stochastic resonance.

关键词： stochastic resonance linear time-delayed feedback loops bistable system

Laboratory test on moisture adsorption-desorption of wall paintings at Mogao Grottoes, China

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第3期13卷 208-218页

作者： Hu-yuan ZHANG Geng-sheng YAN xu-dong wang MOE Key Laboratory of Mechanics on Disaster and Environment in Western China Lanzhou University Lanzhou 730000 China School of Civil Engineering and Mechanics Lanzhou University Lanzhou 730000 China National Engineering Research Center of Ancient Mural Protection Dunhuang 736200 China Dunhuang Academy Dunhuang 736200 China

Moisture adsorption-desorption tests (MATs) were conducted on simulated mural plaster specimens under different air temperatures (ATs) and relative humidity (RH) to investigate the possible effect of seasonal alteration and visitors’ breath on the deterioration of Mogao Grottoes, Dunhuang, China. Saturated salt solutions were used to maintain a constant RH, and plant growth cabinets were used to maintain a constant or varying temperature in the simulation test. The weight of specimen was periodically measured to determine the adsorbed or desorbed moisture. Test data illustrate that the desorption process is far quicker than the adsorption one, indicating that it is possible to inhibit the disadvantage effect from visitors, such as shortening the staying time in caves. In case of high humidity, an accumulated moisture adsorption was found to correspond to the varying temperature. On the other hand, in case of low humidity, accumulated moisture desorption corresponded. Test data imply that opening caves more often to visitors in humid seasons should be avoided so as to prevent continuous wetting of wall paintings.

关键词： Mogao Grottoes Wall paintings Piaster Moisture adsorption-desorption Unsaturated soil

Development of metal-organic deposition-derived second-generation high-temperature superconductor tapes and artificial flux pinning

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2023年第3期11卷 523-540页

作者： dong-xu wang Jing Chen Di-Fan Zhou Chuan-Bing Cai Shanghai Key Laboratory of High Temperature Superconductors Shanghai Frontiers Science Center of Quantum and Superconducting Matter StatesDepartment of PhysicsShanghai UniversityShanghai 200444People's Republic of China Shanghai Creative Superconductor Technologies Co.Ltd. Shanghai 201401People's Republic of China

The second-generation high-temperature superconductor tape(2G-HTS,also known as a coated conductor)based on REBaCuO(REBa_(2)Cu_(3)O_(7-δ))exhibits high current density and potential cost-effective price/performance,compared with conventional superconducting *** commercial 2G-HTS tapes,more than a dozen cable vendors had been manufacturing REBCO cables,such as the latest kilometer-class REBCO cable,which was incorporated into a civil grid on December 2021,as part of the recordbreaking 35-kV-voltage superconductor cable demonstration project in downtown *** paper describes the development of HTS-coated conductors,then outlines the various technological routes for their preparation,reviews the artificial flux pinning of coated conductors,and finally summarizes the technological breakthroughs,the latest research advances,and provides an outlook on their application prospects.

关键词： High-temperature superconductors RE123 superconductor tapes Chemical solution deposition Flux pinning

Thermal conductivity prediction of MgAl2O4:a non-equilibrium molecular dynamics calculation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第5期27卷 500-505页

作者： Cheng-ming Ni Hua-wei Fan xu-dong wang Man Yao School of Materials Science and Engineering Dalian University of TechnologyDalian 116000LiaoningChina

Magnesium aluminate spinel(MgAl2O4)is widely used in steel metallurgy *** conductivity at high temperature signifcantly infuences the cooling process of blast furnace and the heat preservation of steel *** efect of external(temperature)and internal(antisite defect and grain boundary)factors on the thermal conductivity of MgAl2O4 was studied with non-equilibrium molecular *** main factors afecting the thermal conductivity of MgAl2O4 were *** the temperature range of 100-2000 K,the results showed that the thermal conductivity of MgAl2O4 changed from 11.54 to 4.95 W/(m K)with the increase in temperature and was relatively stable at the temperature above 1000 *** thermal conductivity of MgAl2O4 declined frst and then rose with the increase in the antisite defects,and the minimum value was 6.95 W/(m K)at the inversion parameter i=*** addition,grain boundaries reduced the thermal conductivity of MgAl2O4 by 20%-30%at temperature below 1000 K comparing with the non-grain boundary *** grain boundary rotation angle at temperature above 1000 K had less efect on the thermal conductivity than that below 1000 *** simulation scheme for thermal conductivity of MgAl2O4 can also be applied to the study of other nonmetallic ceramics.

关键词： Non-equilibrium molecular dynamics Thermal conductivity Magnesium aluminate spinel Antisite defect Grain boundary

Virtual instrument for monitoring process of brush plating

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第z1期14卷 126-131页

作者： JING xue-dong xu Bin-shi wang Cheng-tao ZHU Sheng dong Shi-yun School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200030 China National Key Laboratory for Remanufacturing Academy of Armored Force Engineering Beijing 100072 China National Key Laboratory for Remanufacturing Academy of Armored Force Engineering Beijing 100072 China School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200030 China National Key Laboratory for Remanufacturing Academy of Armored Force Engineering Beijing 100072 China National Key Laboratory for Remanufacturing Academy of Armored Force Engineering Beijing 100072 China

A virtual instrument(Ⅵ) was developed to monitor the technological parameters in the process of brush plating, including coating thickness, brush-plating current, current density, deposition rate, and brush plating voltage. Meanwhile two approaches were presented to improve the measurement accuracy of coating thickness. One of them aims at eliminating the random interferences by moving average filtering; while the other manages to calculate the quantity of electricity consumed accurately with rectangular integration. With these two approaches, the coating thickness can be measured in real time with higher accuracy than the voltage-frequency conversion method. During the process of plating all the technological parameters are displayed visually on the front panel of the Ⅵ. Once brush current or current density overruns the limited values, or when the coating thickness reaches the objective value, the virtual will alarm. With this Ⅵ, the solution consumption can be decreased and the operating efficiency is improved.

关键词： brush plating virtual instrument coating thickness measurement nano-composite coating

Surface and interface analysis of HAP/TiO2 composite films on Ti6Al4V

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第z1期14卷 193-198页

作者： SU Bing ZHANG Weng-guang YU xu-dong wang Cheng-tao School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai 200030 China School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai 200030 China 1st Department Artillery Academy of PLA of China Hefei 230031 China School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai 200030 China

The composite films constituted of hydroxyapatite (HAP) submicron particles embedded in the gel composed of the titania nanoparticles were prepared on commercial Ti6Al4V plates with titania buffer layer obtained by a spin-coating technique. The films were annealed in air at 450 ℃, 550 ℃ and 650 ℃, respectively. The phase formation, surface morphology, andinterfacial microstructure of the films were investigated by X-ray diffraction(XRD),Fourier transform infrared spectroscopy (FT-IR), field emission-scanning electron microscopy(FE-SEM) and energy dispersive X-ray (EDS) analysis. The results show that the as-prepared films are all well-crystallized, dense,homogeneous, and there was a close interfacial bond between the film and the substrate. The results of adhesion test indicate that there is a good bonding strength between the film and the substrate. The bone-like apatite formation on the surface of the films after immersion in acellular simulatedbody fluid(SBF) validated their bioactivities.

关键词： titanium dioxide hydroxyapatite composite film spin-coating technique

Mold breakout prediction based on computer vision and machine learning

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第8期31卷 1947-1959页

作者： Yan-yu wang Qi-can wang Yong-chang Zhang Yong-hui Cheng Man Yao xu-dong wang School of Materials Science and Engineering Dalian University of TechnologyDalian 116024LiaoningChina Key Laboratory of Solidification Control and Digital Preparation Technology Dalian University of TechnologyDalian 116024LiaoningChina

Breakout is the most serious production accident in continuous casting and must be detected and predicted by stable and reliable *** sticking region,which forms on the local copper plate and expanded into a"V"shape,is the typical precursor of ***,computer vision technology was exploited to visualize the temperature change rate of the copper plate based on the temperature signals from thermocouples;then,the static and dynamic features of the abnormal sticking region were ***,logistic regression and Adaboost models were used to study and identify these features,resulting in the development of a mold breakout prediction model based on computer vision and machine *** test results demonstrate that the proposed model can effectively distinguish anomalous temperature patterns and considerably reduce false alarms without any missing *** a result,the proposed method could offer valuable insights into the realm of abnormality detection and prediction during continuous casting process.

关键词： Abnormality detection Image processing Adaboost Logistic regression Continuous casting

Analysis of Non-uniform Mechanical Behavior for a Continuous Casting Mold Based on Heat Flux from Inverse Problem

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第2期23卷 83-91页

作者： Feng-ming DU xu-dong wang Yu LIU Tian-yi LI Man YAO School of Materials Science and Engineering Dalian University of Technology

The distortion of mold plates plays an important role in the formation of surface cracks on continuously cast steel products. To investigate the non-uniform distortion of a mold, a full-scale stress model of the mold was de veloped. An inverse algorithm was applied to calculate the heat flux using the temperatures measured by the thermo- couples buried inside the mold plates. Based on this, a full-scale, finite-element stress model, including four copper plates, a nickel layer and water slots in different depths, was built to determine the complex mechanical behavior of the continuous casting mold used to produce steel slabs. The heat flux calculated by the inverse algorithm was applied to the stress model to analyze the non-uniform mechanical behavior. The results showed that the stress and distortion distributions of the four copper plates were not symmetrical, which reflected the non-uniform distortion behaviors of copper plates, water slots, nickel layer and the corner region of the mold. The gap between the mold and the slab was increased because of the corner distortion, which was very important for the heat transfer of initial solidifying shell, and it may be a major reason for the slow cooling of the slab corner.

关键词： finite-element stress model inverse algorithm nickel layer water slots continuous casting mold