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Effect of Mg Addition on Nucleation of Intra-granular Acicular Ferrite in Al-killed Low Carbon Steel

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Journal of Iron and Steel Research International 2016年第5期23卷 415-421页

作者： Xiao-bing LI yi min Zhe YU Cheng-jun LIU Mao-fa JIANG Key Laboratory for Ecological Metallurgy of Multimetallic mineral(ministry of Education) Northeastern University

To verify the formation behaviors and mechanisms of intra-granular acicular ferrite（ IAF） grains nucleated by Mg-Al-O in low carbon steel,the steels containing different Mg contents were refined in a vacuum induction furnace. The effect of Mg addition on the formation of IAF structure in Al-killed low carbon steel was investigated by optical microscope（ OM） and scanning electron microscope with energy dispersive X-ray spectroscope（ SEM-EDX）. It reveals that the IAFs are only detected in Mg-added steels,and the volume fraction of IAF increases with the Mg concentration from 8 × 10^（-6） to 26 × 10^（-6）. It shows that not only the MgO-Al_2O_3-MnS and MgO-Al_2O_3-P_2O_5 particles are the effective nucleation sites for IAF,but also the pure MgO·Al_2O_3 phase can promote the ferrite nucleation. A Mn-depletion zone（ MDZ） is characterized adjacent to the MgO-Al_2O_3-MnS,which is believed to be one of the possible mechanisms to explain the IAF nucleation. The MDZ around the MgO-Al_2O_3-MnS inclusion would be induced by the Mn S precipitation on the inclusion. It seems that the ability of Mg-containing inclusions to induce the nucleation of ferrite might be attributed to a new mechanism,i. e.,the Prich zone formed on a few Mg-Al-O inclusions might be another factor for promoting the IAF formation.

关键词： low carbon steel inclusion magnesium intra-granular acicular ferrite Mn-depletion zone

Theoretical Study of Iron Porphyrin Imine Specie of P411 Enzyme:Electronic Structure and Regioselectivity of C(sp^(3))-H Primary Amination

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Chinese Journal of Structural Chemistry 2021年第11期40卷 1411-1422,1405页

作者： LI Shuang WEN Zi-Hao ZHANG min-yi College of Chemistry Fuzhou UniversityFuzhou 350108China Fujian Institute of Research on the Structure of Matter Chinese Academy of SciencesFuzhou 350002China

The cytochrome P411 enzyme is a variant of cytochrome P450_(BM3) from Bacillus megaterium whose active site is an iron porphyrin imine([Fe(Por)(NH)]^(-))*** specie has been reported to successfully promote the primary amination of benzylic and allylic C(sp^(3))-H *** employed density functional theory to study the electronic structure of the active site of P411 enzyme and the primary amination of C-H bond reaction that it *** calculated spin densities and orbital values indicate the existence of resonance in this specie;namely,[(por)(–OH)Fe^(Ⅳ)–N^(2-)–H]^(-)↔[(por)(–OH)Fe^(Ⅲ)–N^(·-)–H]^(-).The amination of C(sp^(3))-H bonds consists of two main reaction steps:hydrogen-atom abstraction and radical recombination,and the former is demonstrated to be the rate-determining ***,we studied the regioselectivity of the amination of primary and secondary C(sp^(3))-H *** calculations indicated that the secondary C(sp^(3))-H bonds of the substrate would be more favored for the activation by P411 *** results provide valuable information for understanding the properties and selectivity of C-H/C-N bond-activation reactions catalyzed by the P411 enzyme or other similar enzymes.

关键词： DFT cytochrome P411 enzyme C-H bond activation enzyme catalysis

3D non-isothermal phase-field simulation of microstructure evolution during selective laser sintering

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npj Computational Materials 2019年第1期5卷 442-453页

作者： Yangyiwei Yang Olav Ragnvaldsen Yang Bai min yi Bai-Xiang Xu Mechanics of Functional Materials Division Institute of Materials ScienceTechnische Universität Darmstadt64287 DarmstadtGermany Department of Materials Science and Engineering Norwegian University of Science and Technology7491 TrondheimNorway State Key Laboratory of Mechanics and Control of Mechanical Structures&Key Laboratory for Intelligent Nano Materials and Devices of ministry of Education&College of Aerospace Engineering Nanjing University of Aeronautics and Astronautics(NUAA)210016 NanjingChina

During selective laser sintering(SLS),the microstructure evolution and local temperature variation interact *** of conventional isothermal sintering model is thereby insufficient to describe *** this work,we construct our model from entropy level,and derive the non-isothermal kinetics for order parameters along with the heat transfer equation coupled with microstructure *** from partial melting and laser-powder interaction are also *** then perform 3D finite element non-isothermal phase-field simulations of the SLS single *** confront the high computation cost,we propose a novel algorithm analogy to minimum coloring problem and manage to simulate a system of 200 grains with grain tracking algorithm using as low as 8 non-conserved order ***,applying the model to SLS of the stainless steel 316L powder,we identify the influences of laser power and scan speed on microstructural features,including the porosity,surface morphology,temperature profile,grain geometry,and *** further validate the first-order kinetics of the transient porosity during densification,and demonstrate the applicability of the developed model in predicting the linkage of densification factor to the specific energy input during SLS.

关键词： microstructure isothermal kinetics

Preliminary Results on the First Optical Molasses of Cs Atoms in China

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Chinese Physics Letters 1998年第6期15卷 413-415页

作者： HOU Ji-dong LI yi-min YANG Dong-hai WANG yi-qiu Department of Electronics Peking UniversityBeijing 100871

Based on an improved optical system,which consists of six laser diodes with two injection locking stages and control set-ups of the intensity and frequency of the laser,we have achieved the first optical molasses in *** time-of-flight(TOF)signal of the cloud of Cs atoms has been obtained,and an analytical-formula for measuring the temperature of the atomic cloud from its TOF signal is *** lowest temperature of the cloud of Cs atoms is measured to be 10μK.

关键词： optical laser signal

Morphological and mineralogical characterizations of oolitic iron ore in the Exi region, China

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International Journal of minerals,Metallurgy and Materials 2013年第2期20卷 113-118页

作者： Shao-xian Song Ernesto Fabian Campos-Toro yi-min Zhang Alejandro Lopez-Valdivieso School of Resources and Environmental Engineering Wuhan University of Technology Instituto de Metalurgia Universidad Autonoma de San Luis Potosi

The morphological and mineralogical characterizations of a Chinese oolitic iron ore （Exi deposit） were studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy in this work. It is shown that the Exi ore is mainly composed of hematite, quartz, apatite, and chlorite. The hematite is present as the oolitic layers and in the spaces between the aggregated ooids; quartz exists as granular particles in the spaces and as nucleuses in ooids; the harmful mineral, apatite, is associated with hematite as the oolitic layers, fine dissemination, granular particles in the spaces, and nucleuses in ooids. From the viewpoint of mineral beneficiation, it is hard to separate apatite and chlorite but easy to separate quartz from hematite in the Exi iron ore in recovering the iron values.

关键词： iron ores mineralogy morphology scanning electron microscopy

Magneto-Optical Trap of Cesium Atoms

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Chinese Physics Letters 1996年第11期13卷 821-824页

作者： GAN Jian-hua LI yi-min CHEN Xu-zong LIU Hai-feng YANG Dong-hai WANG yi-qiu Department of Electronics Peking UniversityBeijing 100871 Permanent address:Shaanxi Astronomical Observatory Chinese Academy of SciencesLintong 710600

We have trapped a cold sample of cesium atoms in a magneto-optical *** damped harmonic force of magneto-optical trap was used to capture and trap the cesium atoms directly from a room temperature *** 1.5×10^(7) cesium atoms with a density of 3×10^(9) atoms/cm^(3) formed a 4mm^(3) cesium atomic cloud with temperature below 500μK.

关键词： harmonic cesium magneto

An Improved Magneto-Optical Trap for Cesium Atom

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Chinese Physics Letters 1998年第5期15卷 335-337页

作者： HOU Ji-dong LI yi-min YANG Dong-hai WANG yi-qiu Department of Electronics Peking UniversityBeijing 100871

Based on the realization of magneto-optical trap for cesium atom in China,great improvement is achieved on its *** the new experimental setup,a laser battery in stepwise injection-locking scheme is developed as laser source,which has more output power and better beam quality than the previous *** the optimum working condition,cesium atoms of more than 10^(9) with the density of 10^(11) atoms/cm^(3) are trapped to form an atomic cloud with the diameter of *** with previous results,both the number of trapped atoms and the density of atomic cloud are increased in two orders of magnitude.

关键词： realization stepwise orders

Long-term results of liver transplantation for over 60 years old patients with hepatitis B virus-related end-stage liver disease

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Hepatobiliary & Pancreatic Diseases International 2014年第5期13卷 501-507页

作者： Shu-Hong yi Hui-min yi Bin-Sheng Fu Chi Xu min-Ru Li Qi Zhang Yang Yang Gui-Hua Chen Liver Transplant Center Third Affiliated Hospitaland Transplantation Research Institute Sun Yat-Sen University

BACKGROUND： Hepatitis B virus（HBV）-related end-stage liver disease is the leading indication for liver transplantation in China, but long-term results of liver transplantation in patients aged over 60 years are not clear. The present study was to reveal the natural history of liver recipients with hepatitis B older than60 ***： The recipients who had received liver transplantation between December 2003 and December 2005 were divided into two groups： those equal or older than 60 years（older group,n60） and those younger than 60 years（younger group, n305）.Risk factors for poor long-term outcome in patients aged over 60 years were also ***： Except for age and preexisting chronic disease（P0.05）,no significant differences were observed in perioperative characteristics between the two groups. There was also no significant difference in HBV and hepatocellular carcinoma recurrence（P0.05）. The actuarial 1-, 3-, 5- and 8-year survival rates were 81.6%, 71.6%, 66.7% and 63.3% respectively for the older group vs 84.9%, 77.7%, 70.8% and 65.6% for the younger group（P0.05）. Multivariate analyses showed that pre-liver transplant renal insufficiency was a risk factor for poor outcome in the older group（odds ratio=3.615, P0.014）.CONCLUSIONS： Liver transplantation is safe and feasible for patients with HBV-related end-stage liver disease aged over 60years. Older patients with renal insufficiency should undergo transplantation earlier than younger patients.

关键词： ge hepatitis B virus liver transplantation renal insufficiency long-term

Melatonin protects liver from intestine ischemia reperfusion injury in rats

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World Journal of Gastroenterology 2008年第48期14卷 7392-7396页

作者： Jian-yi Li Hong-Zhuan yin Xi Gu Yong Zhou Wen-Hai Zhang yi-min Qin The Fifth Department of General Surgery Shengjing Affiliated Hospital of China Medical University Shenyang 110004 Liaoning Province China The Second Department of General Surgery Shengjing Affiliated Hospital of China Medical University Shenyang 110004 Liaoning Province China The Sixth Department of General Surgery Shengjing Affiliated Hospital of China Medical University Shenyang 110004 Liaoning Province China Department of General Surgery The First People's Hospital of Shenyang Shenyang 110004 Liaoning Province China

AIM: To investigate the protective effect of melatonin on liver after intestinal ischemia-reperfusion injury in rats. METHODS: One hundred and fifty male Wistar rats, weighing 190-210 g, aged 7 wk, were randomly divided into melatonin exposure group, alcohol solvent control group and normal saline control group. Rats in the melatonin exposure group received intraperitoneal (IP) melatonin (20 mg/kg) 30 min before intestinal ischemia-reperfusion (IR), rats in the alcohol solvent control group received the same concentration and volume of alcohol, and rats in the normal saline control group received the same volume of normal saline. Serum samples were collected from each group 0.5, 1, 6, 12, and 24 h after intestinal IR. Levels of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured with an auto-biochemical analyzer. Serum TNF-α was tested by enzyme-linked immunosorbent assay (ELISA). Malondialdehyde (MDA) in liver was detected by colorimetric assay. Pathological changes in liver and immunohistochemical straining of ICAM-1 were observed under an optical microscope. RESULTS: The levels of ALT measured at various time points after intestinal IR in the melatonin exposure group were significantly lower than those in the other two control groups (P < 0.05). The serum AST levels 12 and 24 h after intestinal IR and the ICAM-1 levels (%) 6, 12 and 24 h after intestinal IR in the melatonin exposure group were also significantly lower than those in the other two control groups (P < 0.05). CONCLUSION: Exotic melatonin can inhibit the activity of ALT, AST and TNF-α, decrease the accumulation of MDA, and depress the expression of ICAM-1 in liver after intestinal IR injury, thus improving the liver function.

关键词： Melatonin Intestinal ischemia-reperfusion injury Liver TNF-α