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Analysis of Strip Temperature in Hot Rolling Process by Finite Element Method

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Journal of Iron and Steel Research International 2010年第2期17卷 17-21页

作者： MEI Rui-bin LI chang-sheng liu Xiang hua HAN Bin State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Technical Center Wuhan Iron and Steel Group Co Wuhan 430080 Hubei China

The program was developed by finite element method to calculate the temperature distribution in hot strip rolling process. The heat transfer coefficients of air cooling, water cooling and thermal resistance between work roll and strip were analyzed, A new heat generation rate model was proposed according to the influence of source current density, work frequency, air gap and distance to edge on induction heating by finite element method （FEM）. The heat generation rate was considered in the thermal analysis to predict the temperature distribution in the induction heating. The influence of induction heating on the strip temperature was investigated for different slab thicknesses. The temperature difference became more and more obvious with the increase of thickness. The strip could be heated quickly by the induction heating both in surface and center because of the thermal conductivity and skin effect. The heat loss of radiation has important influence on the surface temperature. The surface temperature could be heated quickly by high frequency when the strip is thicker.

关键词： temperature distribution finite element method induction heating skin depth hot rolling

Behavior of Transversal Crack on Slab Corner During V-H Rolling Process

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Journal of Iron and Steel Research International 2006年第6期13卷 31-37页

作者： YU Hai-liang liu Xiang-hua LI chang-sheng Y. Kusaba State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China Sumitomo Metal Industries Ltd Fuso-cho 660 AMAGASAKI Japan

The behavior of transversal cracks on the surface of the slab corner during vertical and horizontal （V-H） rolling process with flat vertical roll and groove vertical roll was simulated by explicit dynamic finite element method. The closure and growth of crack and the contact pressure on surfaces of the crack in contacting zone between slab and roll during rolling process were analyzed. The results showed that during vertical rolling process, when the groove vertical roll is used, the maximum contact pressure on surfaces of the crack is 115 MPa, and the closure of crack is stable when the flat vertical roll is used, the maximum contact pressure on surfaces of the crack is 70 MPa, and it fluctuates greatly. During horizontal rolling process, when groove vertical roll is used, the contact pressure becomes zero which may accelerate the growth of crack when flat vertical roll is used, there is still contact pressure. The cal culated results are in good agreement with the results of test.

关键词： slab crack V-H rolling process FEM

Evolution of Precipitates of S31042 Heat Resistant Steel During 700℃ Aging

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Journal of Iron and Steel Research International 2013年第10期20卷 113-121页

作者： WANG Jing-zhong liu Zheng-dong BAO Han-sheng CHENG Shi-chang Xi'an University of Architecture and Technology Central Iron and Steel Research Institute

The evolution of precipitates of S31042 steel during 700 ℃ aging was investigated by using a scanning elec- tron microscope, a transmission electron microscope, and electron energy spectrum technology. The various combi nations of M23C6, MX, NbCrN, and σ and G phases in the steel were found at different aging states. In the begin ning of aging, M23C6 precipitates swiftly along the grain boundaries. When the aging time exceeds 6 000 h, precipita- ted M23C6 carbides along the grain boundaries turn to be granular. It was found that Si element segregates to grain boundaries during above process, which may enhance the granular shape of M23C6 carbides and its transformation to and G phases. When the aging time exceeds 10 000 h, various shaped a phase and granular G phase appear along the grain boundaries and there are no continuous M23C6 carbides along the grain boundaries. Meanwhile, a large quantity of granular M23C6 carbides and a minor amount of G phase precipitate near the grain boundaries. Based on the segre- gation of silicon to the grain boundaries, a precipitation evolution model during aging was concluded.

关键词： S31042 heat resistant steel aging precipitation evolution

The manipulation of light pulse from subluminal to superluminal propagation in a degenerate two-level Cs atomic system

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Science China(Physics,Mechanics & Astronomy) 2014年第12期57卷 2246-2250页

作者： ZHANG Jun Xiang JIANG Qi chang liu Chao ZHANG Xin sheng liu Jin Hong The State Key Laboratory of Quantum Optics and Quantum Optics Devices Institute of Opto-Electronics Shanxi University

We experimentally demonstrate the propagation of light pulse from subluminal to superluminal light based on quantum coher- ence in a degenerate two-level atomic system in a Cs vapor cell. It is shown that the group velocity of light pulse can be switched from subluminal to superluminal propagation via changing the coupling field from a traveling wave to a standing wave, while can also be continuously manipulated by varying the intensity of two waves superposed to form a standing wave. The observed maximum delay and advance times are about 0.45 and 0.54 μs, corresponding to the group velocity of v8 = 168 km/s and ve =-138 krrt/s, respectively. This investigation may have the practical applications of devices for optical tunable delay lines, optical switching and optical buffering.

关键词： group velocity subluminal superluminal quantum coherence standing wave

A learning framework based on weighted knowledge transfer for holiday load forecasting

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Journal of Modern Power Systems and Clean Energy 2019年第2期7卷 329-339页

作者： Pan ZENG chang sheng Min JIN College of Computer Science and Electronic Engineering Hunan University

Since the variation pattern of load during holidays is different than that of non-holidays, forecasting holiday load is a challenging task. With a focus on this problem, we propose a learning framework based on weighted knowledge transfer for daily peak load forecasting during ***,we select source cities which can provide extra hidden knowledge to improve the forecast accuracy of the load of the target city. Then, all the instances which are from source cities and the target city will be weighted and trained by the improved weighted transfer learning algorithm which is based on the TrAdaBoost algorithm and can decrease negative transfer. We evaluate our method with the classical support vector machine method and a method based on knowledge transfer on a real data set, which includes eleven cities in Guangdong province of China,to illustrate the performance of the method. To solve the problem of limited historical holiday load data, we transfer the data from nearby cities based on the fact that nearby cities in Guangdong province of China have a similar economic development level and similar load variation pattern. The results of comparative experiments show that the framework proposed by this paper outperforms these methods in terms of mean absolute percent error and mean absolute scaled error.

关键词： Load forecasting Holiday effect Sparse data Weighted knowledge transfer

Synthesis and Characterization of Zirconia Nanocrystallites by Cationic Surfactant and Anionic Surfactant

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Chinese Journal of Structural Chemistry 2005年第10期24卷 1133-1139页

作者： YU Jian-chang HU sheng-Wei College of Material Science and Engineering Fuzhou University Fuzhou 350002 China

Study on nanomaterials has attracted great interests in recent years. In this article, zirconia nanocrystallites of different structures have been successfully synthesized via hydrothermal methods with cationic surfactant （CTAB） and anionic surfactant （SDS）, respectively. Differential Scanning Calorimeter （DSC-TG）, X-ray Diffractometer （XRD）, Transmission Electron Microscope （TEM）, Ultraviolet-Visible （UV-vis） and N2 adsorption-desorption analyses are used for their structure characteristics. The results show that the cationic surfactant has a distinctive direction effect on the formation of zirconia nanocrystallites, while the anionic surfactant has a self-assembly synergistic effect on them. The sample synthesized with the cationic surfactant presents good dispersion with the main phase of tetragonal zirconia, and the average nanocrystal size is around 15 nm after calcination at 500 ℃. While the sample synthesized with the anionic surfactant exhibits a worm-like mesoporous structure with pure tetragonal phase after calcination at 500 ℃ and with good thermal stability.

关键词： cationic surfactant anionic surfactant zirconia nanocrystallites,mesoporous zirconia

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32P示踪研究激动素对水稻磷代谢的影响

原子能农业应用 1983年第2期 52-55页

作者：丘冠英冯胜彦柳益明何之常武汉大学

本文用32P示踪法研究了细胞激动素（kt）对水稻磷代谢的影响。结果表明,激动素能提高水稻对磷的利用率,促进32P掺入 RNA、DNA 和蛋白中的比例增高,有利于其他生理代谢的进行,从而促进植株根系发育,使植株生长健壮,分蘖数和穗粒数增多,... 详细信息

本文用32P示踪法研究了细胞激动素（kt）对水稻磷代谢的影响。结果表明,激动素能提高水稻对磷的利用率,促进32P掺入 RNA、DNA 和蛋白中的比例增高,有利于其他生理代谢的进行,从而促进植株根系发育,使植株生长健壮,分蘖数和穗粒数增多,为提高水稻产量打下良好的基础。

关键词：水稻激动素动力精植物生长调节物质水稻植株磷代谢示踪研究

Baseflow variations and its causes in a subtropical watershed of southern China

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Journal of Mountain Science 2022年第10期19卷 2817-2829页

作者： liu Zheng sheng Fei liu Shi-yu WANG Yan-yan ZHOU chang-ming GU Chao-jun School of Land Resources and Environment Jiangxi Agricultural UniversityNanchang 330045China Key Laboratory of Poyang Lake Watershed Agricultural Resources and Ecology of Jiangxi Province Nanchang 330045China College of Resources and Environment Huazhong Agricultural UniversityWuhan 430070China Yangtze River Basin Monitoring Center Station for Soil and Water Conservation Changjiang Water Resources CommissionWuhan 430012China

Baseflow is an essential component of streamflow and plays a crucial role in maintaining the stability of ***,few quantitative studies have identified the effects of leading factors on baseflow variation at the small watershed scale,especially in subtropical *** this study,the small watershed(Pengchongjian watershed,2.90 km2),located in Southern China,was considered to explore the quantitative impact of precipitation,evapotranspiration,temperature,and vegetation restoration on *** digital filter method was used to separate baseflow by daily streamflow records from 1983 to *** stepwise regression models were developed for selecting significant influencing factors of baseflow at seasonal and annual *** direct and indirect effects,as well as their quantitative relationships between baseflow and multiple factors,were clarified by the path *** results showed that filtered average annual baseflow significantly decreased(p<0.05),ranging from 72.82 to 305.85 mm,and the average yearly baseflow index was *** addition,various significant influencing factors of baseflow had different direct and indirect effects on baseflow at seasonal and annual *** precipitation was the dominant factor with respect to the direct impact,which directs path coefficient was 0.891 in spring,0.823 in summer,1.599 in autumn,1.332 in winter,and 0.917 in an annual scale,*** terms of the indirect effects,evapotranspiration played a leading role during the spring,autumn,winter,and annual scale,whereas the average temperature was the dominant factor during the ***,results demonstrated that the baseflow variation was mainly attributed to climate *** present works are beneficial for revealing the internal mechanism of the baseflow variations in the study area,and it can provide a scientific basis for managing water resources in the watershed.

关键词： Baseflow separation Baseflow index Climate change Groundwater Pengchongjian watershed

Preparation and performance of a cold gas dynamic sprayed high-aluminum bronze coating

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International Journal of Minerals,Metallurgy and Materials 2018年第11期25卷 1354-1361页

作者： Li Feng chang Guan Ji-rong chang Hai-min Zhai Guo-sheng An Wen-sheng Li School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou 730050China

By mixing preheated high-aluminum bronze powders with different amounts of Al_2O_3 powder, a low-pressure cold-sprayed coating was prepared and sprayed onto a Cr12MoV steel substrate. The hardness of the coating and the bonding strength between the coating and the substrate were tested with a HV-1000 microhardness tester and a mechanical universal testing machine. The surface microstructure, cross-section and tensile fracture surface of the coating were observed with a scanning electron microscope(SEM). Correspondingly, the influences of the preheat treatment temperature of the bronze powder and the Al_2O_3 content on the coating performance were investigated. The results indicate that the hardness of bronze powders decreased and the coating deposition rate increased after the preheating treatment of the bronze powder. The Al_2O_3 content in the mixed powders contributed to the deformation of bronze powders during the spraying process. This trend resulted in varied performance of the coating.

关键词： low-pressure cold spray high-aluminum bronze preheat treatment coating performance