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A review of research on central crack in continuous casting strand

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Journal of Iron and Steel Research International 2023年第6期30卷 1073-1089页

作者： Yong-kun Yang Jia-yu Zhu Wei-an wang Yang wang jian-li wang Guan-jie wang Xiao-ming li School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055ShaanxiChina

Central crack is a common quality defect in continuous casting strand,which is difficult to fully weld in the rolling and forging processes,and has become a key technical problem that restricts the stable production of high-end alloy rod/forging/*** recent years,the central crack control has been one of the main focuses in high quality steel *** order to fully understand the central crack,the research status of central crack characteristics,formation mechanism,influencing factors,and control methods in the world was *** deficiencies in the research of the central crack and the key research directions in the future were pointed out,which will provide references for other scholars in this field of *** is found that alloying elements segregation during solidification and inclusions precipitated at grain boundaries are the main reasons for the central crack formation,while the unreasonable application of production processes can also induce the initiation of central *** optimization of alloying element composition and production process is helpful to reduce the initiation of central *** addition,the quantitative characterization mechanism based on steel grades,temperature,stress,and other factors induced central crack should be established in the further study,forming a systematic quantitative determination criterion and control strategy for coupling the composition,process and thermal/mechanical characteristic.

关键词： Central crack Continuous casting strand Formation mechanism Alloying element Control strategy

Effect of CacO_(3) on volatilization of self-reduced zinc from blast furnace dust

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Journal of Iron and Steel Research International 2022年第9期29卷 1404-1411页

作者： Wei-an wang Xiao-ming li-Yun He Hao-dong Xi jian-li wang Guo-xing Qiu School of Metallurgical Engineering Xi'an University of Architecture and TechnologyXi'an 710055ShaanxiChina

To solve the problem of low reduction extraction rate of zinc from blast furnace dust,the effects of CacO3 addition,reduction temperature,and reduction time on self-reduction zinc extraction were studied through high-temperature reduction experiment,and the mechanism of how CaCO_(3) addition promotes zinc ferrite reduction was *** zinc removal rate can reach 98.82%when the blast furnace dust is reduced at 1000℃ for 25 min by adding 10 mass%CaCO_(3).At low temperature,CaCO_(3) can enhance the reduction and decomposition of ZnFe_(2)O_(4)(which is difficult to reduce)into ZnO and low-valent iron *** CaCO_(3) is decomposed at high temperature,CO_(2) is produced to undergo gasification reaction with carbon in blast furnace dust,and co is generated to provide more reducing agents for the whole reduction *** generated by decomposition can also catalyze the gasification reaction of carbon,thus improving the removal rate of zinc in the reduction process of dust.

关键词： Blast furnace dust Self reducing zinc extraction Calcium carbonate Zinc ferrite

Numerical simulation of nozzle structure to improve eccentric mold electromagnetic stirring in a round bloom mold

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Journal of Iron and Steel Research International 2024年第9期31卷 2173-2185页

作者： jian-li wang Yong-kun Yang Jia-yu Zhu Wei-an wang liang Niu Xiao-ming li School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an710055ShaanxiChina Hengyang Valin Steel Tube Co. Ltd.Hengyang421001HunanChina

A three-dimensional mathematical model coupling electromagnetic,flow,heat transfer,and solidification has been developed to investigate the effect of eccentric mold electromagnetic stirring(EM-EMS)on the flow and heat transfer of molten steel in round blooms with different cross *** uneven distribution of the flow field caused by EM-EMS was improved by changing the straight submerged entry nozzle(SEN)to a four-port *** symmetry index was determined by the velocity distributions on the left and right sides of the center cross section of mold electromagnetic stirring(M-EMS),which quantitatively evaluated the symmetry of EM-EMS on the flow *** the presence of EM-EMS,the maximum temperature difference ofϕ500 mm andϕ650 mm round blooms between the inner and outer curves amounted to 63 and 26 K,*** maximum distinction between the solidified shells in the inner and outer curves was 11.5 and 5.3 mm,*** using the four-port SEN,the temperature and the shell distribution on the inner and outer curves for theϕ500 mm round bloom were almost the *** symmetry indices ofϕ500 mm andϕ650 mm round blooms were increased from 0.55 and 0.70 to 0.77 and 0.87,*** four-port SEN can be used to mitigate the negative impact of EM-EMS on the steel flow field.

关键词： Nozzle structure Eccentric mold electromagnetic stirring Symmetry index Flow behavior Round bloom

Learning Rates for Least Square Regressions with Coefficient Regularization

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Acta Mathematica Sinica,English Series 2012年第11期28卷 2205-2212页

作者： Bao Huai SHENG Pei Xin YE jian li wang Department of Mathematics Shaoxing College of Arts and Sciences School of Mathematical Sciences and LPMC Nankai University

We analyze the learning rates for the least square regression with data dependent hy- pothesis spaces and coefficient regularization algorithms based on general kernels. Under a very mild regularity condition on the regression function, we obtain a bound for the approximation error by esti- mating the corresponding K：-functional. Combining this estimate with the previous result of the sample error, we derive a dimensional free learning rate by the proper choice of the regularization parameter.

关键词： Least square regressions coefficient regularization general kernel M-functional learningrates

Effect of K2TiO(C2O4)2 Addition in Electrolyte on the Microstructure and Tribological Behavior of Micro-Arc Oxidation Coatings on Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第11期30卷 1109-1118页

作者： jian-li wang Wei Yang Da-Peng Xu Xiao-Fei Yao School of Materials Science and Chemical Engineering Xi'an Technological University Xi'an 710021 China

Micro-arc oxidation （MAO） coatings with different concentrations of K2TiO（C2O4）2 in the sodium silicate base electrolyte were prepared on 6061 aluminum alloy with the aim of promoting a better understanding of the formation mechanisms and tribological behaviors of the coatings. Scanning electron microscopy （SEM） assisted with energy-dis- persive X-ray spectroscopy （EDS）, X-ray photoelectron spectroscopy （XPS） and friction test were employed to charac- terize the MAO processes and microstructure of the resultant coatings. Results showed that the composition and microstructure of the coatings were significantly affected by the addition of KETiO（CaO4）2. A sealing microstructure of MAO coating was obtained with the addition of K2TiO（C2O4）2. Ti element from K2TiO（C2O4）2 was only absorbed into the defects of micropores under surface energy in the early stage, while in the later stage, Ti element was predominant in the micropores and distributed on the coatings under plasma discharge to form TiO2. It was demonstrated that Ti and Si elements from the electrolyte could interact with each other during the MAO process and the interaction mechanism was systematically analyzed. Wear resistance of the MAO coatings with K2TiO（C2O4）2 addition was significantly improved compared with that of the MAO coatings without K2TiO（C2O4）2 addition.

关键词： Aluminum alloy Micro-arc oxidation K2TiO(C2O4)2 Coating formation mechanism Tribological behavior

Molecular design,synthesis and biological activities of amidines as new ketol-acid reductoisomerase inhibitors

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Chinese Chemical Letters 2008年第6期19卷 651-654页

作者： Bao Lei wang Yong Hong li jian Guo wang Yi Ma Zheng Ming li Elemento-Organic Chemistry Institute State-Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 300071 China

Diamidine （A） was identified in our in vitro bio-assay as a possible inhibitor of ketol-acid reductoisomerase （KARI） from the ACD database search based on the known three-dimensional crystal structure of KARI. An investigation on interaction of A on KARI active sites, led to the design and synthesis of 15 novel monoamidines. Some of those showed better biological activity than A on rice KARI （in vitro） and in greenhouse herbicidal tests （in vivo）. The structure-biological activity relationship was investigated, which provides valuable information to further study of potential KARI inhibitors.

关键词： KARl Molecular design Synthesis Biological activity

Regulating metal-acid double site balance on mesoporous SiO_(2)-Al_(2)O_(3) composite oxide for supercritical n-decane cracking

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Petroleum Science 2024年第4期21卷 2881-2891页

作者： liu-ling Chen Jun Zhang Chun-Guang li li-Qun Fei Bo wang Chen-Qi Zhang Yi Jiao jian-li wang Institute of New Energy and Low-Carbon Technology Sichuan UniversityChengdu610064SichuanChina Science and Technology on Scramjet Laboratory Beijing Power Machinery Research InstituteBeijing100074China Engineering Research Center of Combustion and Cooling for Aerospace Power Ministry of EducationSchool of Chemical EngineeringSichuan UniversityChengdu610064SichuanChina State Key Laboratory of Industrial Vent Gas Reuse Southwest Institute of Chemical Co.LtdChengdu610065SichuanChina

The balance between metal and acid sites directly affects the preparation of high-performance cracking catalysts with high heat sink and low ***,how to control acid-metal sites balance and its relationship with cracking performance are reported *** this work,a series of Pt/Al_(2)O_(3)-SiO_(2) dual sites catalysts with different metal to acid active sites ratio(C_(M)/C_(SA))were constructed by ethanolassisted impregnation method and the impact on n-decane cracking under supercritical conditions was systematically and deeply *** results showed that the conversion and carbon deposition increased gradually with varied C_(M)/C_(SA)and reached the balance at C_(M)/C_(SA)of *** proper ratio C_(M)/C_(SA)(0.13)can balance the deep dehydrogenation coking over metal active sites and high heat sink of cracking over acid active sites,the chemical heat sink reaches amazing 1.75 MJ/kg and carbon deposition is only22.03 mg/cm^(2) at 750℃.Meanwhile,the few metal sites at low C_(M)/C_(SA)and the few strong acid sites at high C_(M)/C_(SA)are the main factors limiting the cracking *** C_(M)/C_(SA)limit the activation of C-H bond and deep dehydrogenation of coking precursor,resulting in relative low cracking activity and carbon deposition,while high C_(M)/C_(SA)limit the activation of C-C bond and increase the deep *** this contribution,design and construction of metal-acid dual sites can not only provide the technical solution for the preparation of high heat sink and low coking cracking catalyst,but also deepen the understanding of the cracking path of hydrocarbon fuel.

关键词： Metal-acid dual sites balance Catalytic cracking Hydrocarbon fuels Chemical heat sink Carbon deposition

A new C_(27)-steroidal glycoside from Ophiopogon japonicus

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Chinese Chemical Letters 2008年第1期19卷 82-84页

作者： jian Zhong wang li Ming Ye Xiao Bing Chen West China College of Pharmacy Sichuan University Chengdu 610041 China

A new C27-steroidal glycoside with three known compounds were isolated from the tuber of Ophiopogonjaponicus （Thunb.） Ker-Gawl. Based on the spectral analysis, including HRMS, 1H NMR, 13C NMR, DEPT, 1H-1H COSY, HMQC and HMBC, their chemical structures were determined as pennogenin-3-O-α-L-rhamnopyranosyl-（1→ 2）-β-D-xylopyranosyl-（1→ 4）-13-D-gluco- pyranoside （1）, pennogenin-3-O-α-L-rhamnopyranosyl-（1→ 2）-β-D-glucopyranoside （2）, ophiopojaponin C （3） and ophiopogonin D （4）. 2007 jian Zhong wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Ophiopogon japonicus C27-steroidal glycoside

A Variable Parameter linear Tracking Differentiator and Its Application in Large Ground-based Telescopes

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Research in Astronomy and Astrophysics 2022年第12期22卷 273-283页

作者： Xiao-Xia Yang Yong-Ting Deng jian-li wang Bin Zhang Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China

This paper is concerned with the characteristics of a tracking differentiator(TD)in arranging transition process for the physical *** order to overcome disadvantages of linear TD(LTD)in practice,a novel variable parameter linear tracking differentiator(VLTD)is *** designing the speediness factor as a function of the tracking error,the VLTD can track a large range of set values with reasonable speed and *** shows that VLTD can converge to its set value under certain ***,the speed and acceleration bounds are added to the VLTD,which guarantees that the proposed transition signal really plays a transitional *** numerical simulation results emphasize necessity for adding speed and acceleration bounds to the *** comparing VLTD with the nonlinear TD(NLTD)in the simulations and experiments,VLTD can achieve almost the same performance as the NLTD while it is easier to be implemented.

关键词： methods:data analysis methods:analytical methods:numerical telescopes