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Mathematical Model for Electroslag Remelting Process

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Journal of Iron and Steel Research International 2007年第5期14卷 7-12,30页

作者： dong yan-wu JIANG Zhou-hua LI Zheng-bang School of Materials and Metallurgy Northeastern University Shenyang 110004 Liaoning China Institute for Metallurgical Technology Central Iron and Steel Research Institute Beijing 100081 China

A mathematical model, including electromagnetic field equation, fluid flow equation, and temperature field equation, was established for the simulation of the electroslag remelting process. The distribution of temperature field was obtained by solving this model. The relationship between the local solidification time and the interdendritic spacing during the ingot solidification process was established, which has been regarded as a criterion for the evaluation of the quality of crystallization. For a crucible of 950 mm in diameter, the local solidification time is more than 1 h at the center of the ingot with the longest interdendritic spacing, whereas it is the shortest at the edge of the ingot according to the calculated results. The model can be used to understand the ESR process and to predict the ingot quality.

关键词： electroslag remelting mathematical model interdendritic spacing local solidification time

Transition-Metal-Free Allylic Defluorination Cross-Electrophile Coupling Employing Rongalite

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Chinese Journal of Chemistry 2024年第12期42卷 1360-1366页

作者： Xiang-Long Chen Chun-yan wu dong-Sheng yang Bo-Cheng Tang Huai-Yu Wang Zhi-Cheng Yu Anling Li yan-dong wu An-Xin wu National Key Laboratory of Green Pesticide International Joint Research Center for Intelligent Biosensor Technology and HealthCollege of ChemistryCentral China Normal UniversityWuhanHubei 430079China state Key Laboratory of Chemical Biology and Drug Discovery Department of Applied Biology and Chemical Technology The HongKong Polytechnic UniversityKowloonHong Kong SARChina Department of Clinical Laboratory Center for Gene Diagnosisand Program of Clinical Laboratory MedicineZhongnan Hospital of Wuhan UniversityWuhanHubei 430062China

Comprehensive Summary The conversion of CF3-alkenes to gem-difluoroalkenes using reductive cross-coupling strategy has received much attention in recent years,however,the use of green and readily available reducing salt to mediate these reactions remains to be *** this work,a concise construction of gem-difluoroalkenes,which requires neither a catalyst nor a metal reducing agent,was ***,a safe and inexpensive industrial product,was employed as both a radical initiator and *** procedure was compatible with both linear and cyclic diaryliodonium salts,enabling a wide variety of substrates(>70 examples).The utility of this approach was demonstrated through gram-scale synthesis and efficient late-stage functionalizations of anti-inflammatory drugs.

关键词： Defluoroarylation Transition metal free gem-Difluoroalkenes Rongalite Single electron transfer C-C coupling Redox reactions Cross-coupling

Segregation of Niobium During Electroslag Remelting Process

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Journal of Iron and Steel Research International 2009年第1期16卷 7-11页

作者： dong yan-wu JIANG Zhou-hua LI Zheng-bang School of Materials and Metallurgy Northeastern University Shenyang 110004 Liaoning China Central Iron and Steel Research Institute Beijing 100081 China

Experiment was carried out after the process parameters were calculated by the model previously established. The relationship between interdendritic spacing and local solidification time （LST） mainly determined by process parameters was exposed. Furthermore, the extent of segregation was studied. The results indicate that LST and interdendritic spacing are the largest and the amount of Laves phase as a result of the niobium segregation is the highest in the center of the ingot, whereas the opposite results are obtained at the edge of ingot. The extent of element segregation and the amount of Laves phase can be reduced when appropriate parameters are used. Therefore, the duration of subsequent homogenization treatments for 718 is shortened and the alloy quality is improved.

关键词： electroslag remelting Inconel 718 segregation local solidification time interdendritic spacing

Hydrogen Pick-Up During Electroslag Remelting Process

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Journal of Iron and Steel Research International 2011年第4期18卷 19-23页

作者： JIANG Zhou-hua dong yan-wu LIANG Lian-ke LI Zheng-bang School of Materials and Metallurgy Northeastern University Shenyang 110004 Liaoning China Central Iron and Steel Research Institute Beijing 100081 China

The pick-up of hydrogen during electroslag remelting process for several slags consisting of CaF2-Al2O3-CaO-SiO2-MgO had been *** laboratory-scale remelting experiments had been carried out in open air and water-free argon atmosphere,and then the influencing factors were *** had been found that the hydrogen content in steel varied with different slag *** compositions and state of slag had significant effect on the hydrogen level in *** return slag and premelted slag could avoid the hydrogen pick-up especially in the early stages of the ***,premelted slag was the optimum state to control the hydrogen pick-up in *** results indicated that water-free argon atmosphere was very favorable to the control of hydrogen in steel in the normal remelting period.

关键词： electroslag remelting hydrogen calcium fluoride premelted slag protective atrriosphere

Calcination of Slags for Electroslag Remelting

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Journal of Iron and Steel Research International 2010年第8期17卷 1-5页

作者： dong yan-wu JIANG Zhou-hua XIAO Zhi-xin LI Zheng-bang School of Materials and Metallurgy Northeastern UniversityShenyang 110004LiaoningChina Central Iron and Steel Research Institute Beijing 100081China

The hydrides in industrial lime,alumina,magnesia,and calcium fluoride were investigated through differential thermal analysis and X-ray diffraction,and their mass losses during heating up were studied by thermogravimetric analysis *** results indicate that the industrial alumina,lime,and magnesia,which have more moisture or hydride and mainly include γ-Al2O3,Ca（OH）2,and Mg（OH）2,lose more mass during thermogravimetric analysis ***,the mass of premelted slag consisting of lime,fluorite,alumina,and magnesia has almost no change,which means no hydride in *** relationships for calculating the mass loss were established according to the results of thermogravimetric *** results will be in favor of setting up the rational calcination criterion for slag used in electroslag remelting process.

关键词： electroslag calcination differential scanning calorimeter X-ray thermogravimetric analysis

I_(2)-DMSO-Mediated Multicomponent [2+1+1+1] Annulation Reaction via Ethyl Nitroacetate C-NO_(2), Bond Cleavage as a C1 Synthon: A Route to Multisubstituted β-Pyrrolidinones Derivatives with a Quaternary Center

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Chinese Journal of Chemistry 2024年第17期42卷 2029-2034页

作者： Zhi-Cheng Yu Xi Shen You Zhou Xiang-Long Chen Li-Sheng Wang yan-dong wu An-Xin wu National Key Laboratory of Green Pesticide International Joint Research Centerfor Intelligent BiosensorTechnologyand HealthCollegeof ChemistryCentral ChinaNormal UniversityWuhanHubei 430079China

A[2+1+1+1]cyclization reaction has been developed for the synthesis of multisubstituted 6-pyrrolidinones from commercially available aryl methyl ketones,primary amines,and ethyl *** this I_(2)-DMSO-meditated process,the C-NO_(2) bond of ethyl nitroacetate is cleaved,affording a C1 synthon,and the formation of two C-C and two C-N bonds and a quaternary carbon center are constructed in one *** method has good substrate compatibility and permits the late-stage modification of pharmaceutical compounds.

关键词： Cyclization Multisubstitutedβ-pyrrolidinones I_(2)-DMSO C1 building blocks Quaternary carbon center Late-stage modification Cracking

Effects of propyl gallate on interaction between TNF-α and sTNFR-I using an affinity biosensor

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Acta Pharmacologica Sinica 2005年第10期26卷 1212-1216页

作者： Jing LI, Jia-dong HUANG, Bao-yan wu, Qiang CHEN~2 Laboratory of Biosensors, College of Life Science, Nankai University, Tianjin 300071, China Laboratory of Biosensors College of Life Science Nankai University Tianjin China

Aim: To study the effects of propyl gallate on the interaction of tumor necrosisfactor-α(TNF-α) with its soluble receptor, sTNFR-I. Methods: Interactions between TNF-α and sTNFR-I were analyzed using an IAsys biosensor, sTNFR-Iwas immobilized on the carboxymethyl dextran (CMD) surface of the IAsys biosensor cuvettes, and TNF-α preincubated with different concentrations of propylgallate was added to the cuvettes. The resonant angle shift caused by the bindingbetween TNF-α and sTNFR-I was then recorded. Results: sTNFR-I was immobilized on the CMD surface at a density of 2.76 ng/mm~2. TNF-α then bound theimmobilized sTNFR-I specifically, and propyl gallate was able to enhance thebinding between TNF-α and sTNFR-Iin a dose-dependent manner. Conclusion:The binding between TNF-α and sTNFR-I is one of the targets that propyl gallatecan act on in vivo. The IAsys biosensor offers a new clue as to the study on themechanisms of action of propyl gallate.

关键词： propyl gallate tumor necrosis factor-α soluble tumor necrosis factor receptor affinity biosensor

Effects of Iron on Growth and Intracellular Chemical Contents of Microcystis aeruginosa

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Biomedical and Environmental Sciences 2010年第1期23卷 48-52页

作者： CHONG WANG,HAI-NAN KONG ,XIN-ZE WANG,HAO-dong wu,yan LIN,AND SHENG-BING HE School of Environmental Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China School of Environmental Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

Objective To investigate the effect of iron on the growth, physiology and photosynthesis of cyanobacteria. Methods A gradient of iron concentrations was employed to investigate the growth, photo-pigments （chlorophyll A and phycocyanin）, and cell chemical contents （C, N, P） of Microcystis aeruginosa in response to different iron additions. Results The specific growth rate during the exponential growth phase, as well as the cell chlorophyll A and the phycocyanin content, was limited by iron below 12.3μmol Fe.L^-1. The growth was inhibited when the iron concentration was at 24.6 μmol Fe.L^-1. The cell chlorophyll A and the phycocyanin content were saturated when the iron concentration was above 12.3μmol Fe.L^-1 and declined slightly at 24.6 μmol Fe.L^-1. At a low iron concentration （about 6.15 μmol Fe-L^-1 and less）, the cell nitrogen and carbohydrate content were iron limited, and the variation of the cell phosphorus content was similar to that of the nitrogen and carbohydrate, with a transition point of 12.3 μmol Fe.L^-1. Conclusion The variation ofcynobacteria growth is synchronous with that of the photo-pigments or the cell chemical content, and there exist relationships among photosynthesis, growth and internal chemical content, which could be useful for the growth estimation from the cell characteristics.

关键词： Iron Growth Photo-pigments Carbohydrate Phosphorus Nitrogen

Annexin A2 promotes choroidal neovascularization by increasing vascular endothelial growth factor expression in a rat model of argon laser coagulation-induced choroidal neovascularization

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Chinese Medical Journal 2010年第6期123卷 713-721页

作者： ZHAO Shi-hong PAN dong-yan ZHANG Yuan wu Jin-hui LIU Xin XU Yu Department of Ophthalmology Changhai HospitalSecond Military Medical UniversityShanghai 200433China

Background Choroidal neovascularization （CNV） is a common cause of visual loss in the elderly patients with age-related macular degeneration and represents the growth of subretinal new vessels in the macular region. This study aimed to investigate the relationship between annexin A2 （ANXA2） and vascular endothelial growth factor （VEGF） in *** In a rat model of argon laser coagulation-induced CNV, the mRNA expressions of the annexins and VEGF protein expression in the retina were detected using fluorescent real-time polymerase chain reaction （PCR） and immunohistochemistry, respectively. The interactions between ANXA2 and VEGF in both a retinal pigment epithelial cell line RPE-J and the rat model of CNV were examined by means of RNA interference, real-time PCR, Western blotting, enzyme-linked immunosorbent assay （ELISA） and histopathological examinations. Results Fundus fluorescein angiography （FFA） showed that argon laser coagulation of the retina induced stable CNV models in the rats. Two to three weeks after the coagulation, ANXA2. and VEGF expressions in the coagulated area in the retina and choroid increased to the peak level, while the other annexin members （ANXA4, ANXA5, ANXA7 and ANXA11） showed no obvious changes. In RPE-J cells and the CNV model, RNA interference of ANXA2 gene significantly lowered the VEGF protein and mRNA expressions, and application of an adenoviral vector containing ANXA2 gene markedly increased VEGF expressions in the rat model of CNV, but produced no significant effects on the expressions of the kinase insert domain-containing receptor （KDR） or the fms-like tyrosine kinase （Fit-l）. The expression of KDR inhibited the increment in ANXA2 expression, but VEGF and Rt-1 did not directly affect ANXA2 expression. Conclusion Besides the role as a plasminogen and the receptor of tissue plasminogen activator, ANXA2, which is under regulation of KDR via a negative feedback mechanism, also participates in neovascularization by regulating VE

关键词： annexin A2 vascular endothelial growth factor choroid neovascularization