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Characteristics of Oxidation and Oxygen Penetration of Alloy 690 in 600°C Aerated Supercritical Water

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Journal of Materials Science & Technology 2018年第3期34卷 561-569页

作者： Xiangyu zhong Xinqiang Wu En-Hou han CAS Key Laboratory of Nuclear Materials and Safety Assessment Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear MaterialsInstitute of Metal ResearchChinese Academy of SciencesShenyang 110016China

The oxide films formed on Alloy 690 exposed to 600 ℃ supercritical water were characterized using mass measurement, X-ray diffraction. Raman spectroscopy, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. It was found that the mass gain of the alloy in supercritical water decreased with increasing exposure time. The oxide films have a double-layer structure, with an inner layer rich in Cr and outer layer rich in Ni and Fe after short time and long time exposure. The penetration of the oxide along the grain boundaries was observed, and the penetration depth increased with increasing exposure time. The grain boundaries and voids are the short-path of oxygen diffusion into the metal.

关键词： Ni-based alloy XPS Supercritical water High temperature corrosion High temperature oxidation Oxide film

Effect of Cooling Rate on Microstructure and Mechanical Properties of K465 Superalloy

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Journal of Iron and Steel Research International 2009年第6期16卷 70-74页

作者： PEI zhong-ye han Wei ZHAO Gang CHEN Xing-fu LI Jun-tao TIAN Yan-wen School of Material and Metallurgy Northeastern University Shenyang 110004 Liaoning China High Temperature Materials Research Division Central Iron and Steel Research Institute Beijing 100081 China

K465 superalloy, as a material for production of turbine nozzle, shows high mechanical properties as well as microstructure stability under critical and severe service conditions. The appropriate microstructure and strength of this alloy can be obtained by solid solution strengthening mechanism. Heat treatment parameters such as time and temperature of homogenization, partial solution and aging temperatures, and cooling rate from solid solution temperature affect the microstructure of the alloy. Among these parameters, cooling rate from solid solution temperature is the most effective. Therefore, the effect of cooling rate on microstructure and mechanical properties （tensile and stress properties） was investigated. For this purpose, three different cooling rates were applied to the cast K465 specimens subjected to solution treatment at 1 483 K for 4 h. Microstructures of the specimens then were studied using optical and electron microscopy. Also, tensile tests were performed at room temperature and stress rupture tests were performed under the condition of 1 248 K and 230 MPa. It was found that with increasing the cooling rate, the size of the γ＇ precipitates decreases and the mechanical properties of specimens increases. Also, it was found that the shape and volume fraction of primary γ＇ particles are largely influenced by the cooling rate after solution treatment at 1 483 K for 4 h.

关键词： cast superalloy solution heat treatment cooling rate microstructure mechanical property

Catalytic asymmetric synthesis of 1,4-enynes

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Chinese Chemical Letters 2023年第8期34卷 18-27页

作者： han-Yu Lu Zhi-tao He CAS Key Laboratory of Synthetic Chemistry of Natural Substances Shanghai Institute of Organic ChemistryUniversity of Chinese Academy of SciencesShanghai 200032China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China School of Chemistry and Materials Science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

1,4-Enyne units are ubiquitous skeletons in biologically active molecules and natural ***,they represent versatile building blocks for abundant downstream derivatizations via controllable modifications of both alkene and alkyne units ***,great efforts have been made to establish efficient protocols to achieve optically active 1,*** the enormous application potential of enantioenriched 1,4-enyne units but no related review on this topic has been described,here we aim to provide a comprehensive summary on the catalytic methods established for enantioselective constructions of these intriguing *** to the reaction types,this review is divided into five parts,including asymmetric allylic substitution,asymmetric propargylic substitution,asymmetric alkynylallylic substitution,asymmetric hydroalkynylation and asymmetric 1,2-addition of alkynes to conjugated imines or ketones.

关键词： 1,4-Enynes Catalytic reaction Asymmetric synthesis

Intrapancreatic accessory spleen:A case report and review of the literature

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World Journal of Gastroenterology 2009年第9期15卷 1141-1143页

作者： Wei Guo Wei han Jun Liu Lan Jin Jian-She Li zhong-tao Zhang Yu Wang Department of General Surgery Beijing Friendship Hospital Capital Medical University Beijing 100050 China

Here,we report a case of intrapancreatic accessory spleen confirmed by pathologic diagnosis and discuss its differential diagnosis and surgical management with a review of the literature.

关键词： Accessory spleen Pancreas Differential diagnosis Surgical management Congenital defect

Preparation of Ultrafine Tungsten Powder by Sol-Gel Method

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Journal of Materials Science & Technology 2008年第5期24卷 816-818页

作者： Yuxian han Tai QIU tao SONG College of Materials Science and Engineering Nanjing University of Technology Nanjing 210009 China

Sol-gel method was employed for the preparation of nanoscale tungsten powder. The effects of different preparation conditions on particle size were discussed and the optimum preparation condition was found. The products were characterized by X-ray diffraction, scan electron microscopy and so on. The results show that the intermediate is monoclinic WO3, its particle shape is approximately spherical, and the particle size distribution is narrow. The average particle size is about 60 nm. After deoxidization, WO3 turns into cubic tungsten powder with small particle size （average particle size about 120 nm） and narrow size distribution.

关键词： Sol-gel method Tungsten trioxide Deoxidize Ultra-fine tungsten powder

Immunogenic molecules associated with gut bacterial cell walls:chemical structures,immune-modulating functions,and mechanisms

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Protein & Cell 2023年第10期14卷 776-785页

作者： Ruopeng Yin tao Wang Huanqin Dai Junjie han Jingzu Sun Ningning Liu Wang Dong Jin zhong Hongwei Liu State Key Laboratory of Mycology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China Savaid Medical School University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China State Key Laboratory of Microbial Resources Institute of MicrobiologyChinese Academy of Sciences100101 BeijingChina

Interactions between gut microbiome and host immune system are fundamental to maintaining the intestinal mucosal barrier and *** the host-gut microbiome interface,cell wall-derived molecules from gut commensal bacteria have been reported to play a pivotal role in training and remodeling host immune *** this article,we review gut bacterial cell wall-derived molecules with characterized chemical structures,including peptidoglycan and lipid-related molecules that impact host health and disease processes via regulating innate and adaptive ***,we aim to discuss the structures,immune responses,and underlying mechanisms of these immunogenic *** on current advances,we propose cell wall-derived components as important sources of medicinal agents for the treatment of infection and immune diseases.

关键词： gut commensal bacteria peptidoglycan lipid-related molecules immune responses

Effect of inorganic salt on the thermal degradation of nitrocellulose and reaction mechanism of its mixture

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Defence Technology（防务技术） 2023年第9期27卷 111-118页

作者： Guo-zhong Xu Xu Gao Mi Li zhong-xuan han Lin Jiang School of Mechanical Engineering Nanjing University of Science and TechnologyChina

In this study,to better understand the reaction mechanism between inorganic salts and nitrocellulose,CaCO_(3) and Li_(2)CO_(3) were evaluated with respect to their effects on the thermal degradation of NC in nitrogen atmosphere using TG/DSC at three different heating rates(2,5,10 K/min).The numerical relationship between activation energy(E)and conversion rate was obtained by FWO and KAS method,and it was discovered that CaCO_(3) could improve the thermal stability of *** energy values were calculated by Kissinger method,and it was found that NC that contain Li2CO3had the highest activation energy while NC containing CaCO3had the lowest E *** combining the thermal analysis data with Malek method,the most probable mechanism model of thermal degradation is obtained as Sesták-Berggren model,which expression is f(α)=α^(m)(1-α)^(n).As a result of this study,there are certain guiding principles that can be applied to the pyrolysis reaction model and to the actual production process of nitrocellulose.

关键词： Thermal analysis Thermal decomposition mechanism Malek method Nitrocellulose Inorganic salt

Two types of hyperthermal events in the Mesozoic-Cenozoic:Environmental impacts, biotic effects, and driving mechanisms

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Science China Earth Sciences 2020年第8期63卷 1041-1058页

作者： Xiumian HU Juan LI zhong han Yongxiang LI State Key Laboratory of Mineral Deposit Research School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China

A deeper understanding of hyperthermal events in the Earth’s history can provide an important scientific basis for understanding and coping with global warming in the Anthropocene. Two types of hyperthermal events are classified based on the characteristics of the carbon isotope excursion(CIE) of the five representative hyperthermal events in the Mesozoic and Cenozoic. The first type is overall characterized by negative CIEs(NCHE) and represented by the Permian-Triassic boundary event(PTB, ~252 Ma), the early Toarcian oceanic anoxic event(TOAE, ~183 Ma), and the Paleocene-Eocene Thermal Maximum event(PETM, ~56 Ma). The second type is overall characterized by positive CIEs(PCHE) and represented by the early Aptian oceanic anoxic event(OAE1 a, ~120 Ma) and the latest Cenomanian oceanic anoxic event(OAE2, ~94 Ma).Hyperthermal events of negative CIEs(NCHE), lead to dramatic changes in temperature, sedimentation, and biodiversity. These events caused frequent occurrence of terrestrial wildfires, extreme droughts, acid rain, destruction of ozone layer, metal poisoning(such as mercury), changes in terrestrial water system, and carbonate platform demise, ocean acidification, ocean anoxia in marine settings, and various degree extinction of terrestrial and marine life, especially in shallow marine. In contrast,hyperthermal events of positive CIEs(PCHE), result in rapid warming of seawater and widespread oceanic anoxia, large-scale burial of organic matter and associated black shale deposition, which exerted more significant impacts on deep-water marine life,but little impacts on shallow sea and terrestrial life. While PCHEs were triggered by volcanism associated with LIPs in deep-sea environment, the released heat and nutrient were buffered by seawater due to their eruption in the deep sea, thus exerted more significant impacts on deep-marine biota than on shallow marine and terrestrial biota. This work enriches the study of hyperthermal events in geological history, not onl

关键词： Hyperthermal events Paleoclimate Paleoceanography Sedimentary record Large igneous province Mesozoic and Cenozoic Deep-time

Simulation on effect of throat contraction ratio and strake stagger angle on flow field and aerodynamic performance of scrampressor

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航空动力学报 2017年第5期32卷 1183-1194页

作者： YANG Ling zhong Jing-jun han Ji-ang Marine Engineering College Dalian Maritime University

The design methods of typical supersonic aircraft intakes and shock wave compression technology have been applied to ram-rotor,an attractive compression system.A ram-rotor is of a typical structure including the compression ramp,the throat and the subsonic diffuser;a scrampressor is similar to ram-rotor,the only difference is that scrampressor has no subsonic *** work was the continuation of the preparatory *** order to further study the effect of throat contraction ratio and strake stagger angle on the flow field and performance of a scrampressor,the flow field of a scrampressor with a three-dimensional flow path was numerically simulated with different throat contraction ratios and strake stagger *** results indicated that the optional aerodynamic performance of a scrampressor could be achieved with an adiabatic efficiency of 0.8413atotal pressure recovery coefficient of 0.8446,a total pressure ratio of 7.14 and a static pressure ratio of 5.17for a throat contraction ratio of 0.6 and a strake stagger angle of 12°.It was therefore concluded that an appropriate decrease in throat contraction ratio and an increase in strake stagger angle could help the comprehensive improvement of a scrampressor in performance.

关键词： scrampressor flow field aerodynamic performance throat contraction ratio strake stagger angle