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Formation of M_(n+1)AX_n phases in Ti–Cr–Al–C systems by self-propagating high-temperature synthesis

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Rare Metals 2014年第4期33卷 419-426页

作者： Guo-Bing ying Xiao-Dong He shan-yi Du Chun-Cheng Zhu Yong-Ting Zheng Yu-Ping Wu Cheng Wang Institute of Metals and Protection College of Mechanics and MaterialsHohai University Center for Composite Materials and Structure Harbin Institute of Technology College of Chemistry and Chemical Engineering Harbin Normal University

In this paper, phase composition of the Mn＋l- AXn phases by self-propagating high-temperature synthesis （SHS） was determined using Ti, Cr, A1, and carbon black as raw materials. And, phase composition and micro- structures of the Mn＋1AXn phases-contained bulk by SHS with the pseudo-hot isostatic pressing （SHS/PHIP） were investigated in Ti-Cr-AI-C systems raw materials. Riet- veld XRD refinement was introduced to study the lattice parameters and phase composition of the resultant phases from the SHSed and SHS/PHIPed samples. Ti2A1Cx, Ti3A1C2, and Cr2A1Cx by SHS were detected in the Ti-Cr- A1-C systems, as well as the binary carbide of TiC and intermetallics. The mechanical properties of the synthe- sized bulk samples were determined, exhibiting a high strength and toughness compared with the typical mono- lithic Mn＋1AXn phase ceramics. It is indicated that the samples prepared by SHS/PHIP are identified to be a strategy for improving the mechanical properties of monolithic Mn＋1AXn phase.

关键词： SHS/PHIP Mn+lAXn phases Phasecomposition Microstructure Mechanical properties

Kinetics and numerical simulation of self-propagating high-temperature synthesis in Ti–Cr–Al–C systems

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Rare Metals 2014年第5期33卷 527-533页

作者： Guo-Bing ying Xiao-Dong He shan-yi Du Yong-Ting Zheng Chun-Cheng Zhu Yu-Ping Wu Cheng Wang Institute of Metals and Protection College of Mechanics and Materials Hohai University Center for Composite Materials and Structure Harbin Institute of Technology College of Chemistry and Chemical Engineering Harbin Normal University

In this paper, Ti–Cr–Al–C materials were investigated by self-propagating high-temperature synthesis（SHS） according to the experimental study and numerical simulation results. The highest adiabatic combustion temperature Tadof 2,467.45 K indicates that the2Ti–0Cr–Al–C is the highest exothermic reaction system in the Ti–Cr–Al–C system. The adiabatic combustion temperature decreases with the increase of the Cr content. And a higher exothermal reaction would result in higher porosity which is induced by the high temperature and pressure of C reducing atmosphere and Al vapor. Combustion characterization of the products shows that the geometrical alternating layers result in the high exothermal reaction and flame-front propagating velocity. The higher the Tadis, the thinner the layer is. To demonstrate the process of the microscopic characterization and show the detailed combustion process closed to the experimental observations, the flame-front propagating velocity and temperature distribution were simulated numerically.

关键词： Self-propagating high-temperature synthesis Temperature distribution Flame-front propagating velocity Numerical simulation

Microstructure and Property of Coarse Grain HAZ X80 Pipeline Steel

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Journal of Iron and Steel Research International 2005年第6期12卷 54-58页

作者： ZHOU Yun XUE Xiao-huai QIAN Bai-nian LI Jing-li shan yi-yin LOU Song-nian shanghai Jiaotong University Shanghai 200030 China Academia Sinica Shenyang 110015 China

The coarse grain HAZ microstructure and property of X80 pipeline steel with different carbon content was investigated. The weld thermal simulation test was carried out on Gleeble 1500 thermal mechanical test machine. The Charpy tests were completed at --20 ℃ for evaluating the toughness of coarse grain heat affected zone （CGHAZ）. The microstructure was examined by optical microscope （OM） and transmission electron microscopy （TEM）, and the austenite constituent was quantified by X-ray diffraction. The results showed that the ultra-low carbon can improve the toughness of CGHAZ by suppressing the formation of carbide, decreasing the martensite austenite （M-A） constituent and increasing the residual austenite in the M A.

关键词： X80 pipeline steel CGHAZ weld simulation FesC carbide ultra low carbon M-A constituent bainitic ferrite

Fabrication of mullite fiber reinforced SIC porous ceramic

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Fabrication of mullite fiber reinforced SIC porous ceramic

All-Solid-State Multi-Wavelength Laser System from 208 to 830 nm

第八届中国功能材料及其应用学术会议

作者： SUN Yang-shan DENG Xiang-yun WANG yi-shan WANG Chuan-fang SHAO Jian YANG Jie SUN Guang-hao HUANG Chuan-jun College of Physics and Electronic Information Tianjin Normal University Key Laboratory of Min-istry of Education for Advanced Materials in TropicalIsland Resources Hainan University

ISBN: (纸本)9783037859698

Ceramic fibers and whiskers have been used for modification of toughness because they increase fracture energy due to their high elastic modulus *** mechanism of this increase is well known to be pull-out,crack deflection and a bridging *** study focused on the increase in toughness,strength and thermal shock resistance when using mullite fibers in a gas filter for high *** green body uses the average 230μm particle diameter of SiC powders,which used as a skeletal material,the length to diameter ratio greater than 10 of the mullite fibers and the mixture of kaolin,feldspar and silica,which was used as a *** pore former be made up of graphite and active *** molding pressure is 3MPa,and sintering temperature is 1300℃.The mullite fiber reinforced SiC porous ceramic haslow filter pressure drop,30.36%porosity and 35.66 MPa flexural strength,which is higher than the SiC porous ceramic whitout mullite *** the flexural strength degradation was only 5.4%after thermal shock tests.

关键词： Mullite fibers Silicon carbide Porous ceramic Gas filter

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Chinese Physics Letters 2001年第4期18卷 537-538页

作者： ZHAO shang-Hong CHEN Guo-Fu ZHAO Wei WANG yi-shan YU Lian-Jun College of Telecommunication University of Air Force EngineeringXi’an 710077 State Key Laboratory of Transient Optics and Technology Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’an 710068

Four-wavelength lasers from near-infrared to deep-ultraviolet range,532,830,415 and 208 nm,have been developed in one all-solid-state laser *** laser system is pumped by a diode-Q-YLF laser at 532 nm,a Ti:sapphire laser and the nonlinear second-harmonic-generation crystals LBO and BBO are used to generate different *** average powers(repetition rate 1 kHz)of 1.1 W at 830 nm,380 mW at 415 nm,and 39 mW at 208 nm are obtained when the pumping power is 3.6 *** main characteristics of this system are presented.

关键词： pumped pumping laser

Promising way to address massive intragastric clotting in patients with acute upper gastrointestinal bleeding:A case report

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World Journal of Clinical Cases 2023年第15期11卷 3578-3582页

作者： Su-Xian Liu Bei Shi Ya-Feng Liu Jing-yi shan Bo Sun Department of Gastroenterology Longhua Affiliated Hospital of Shanghai Traditional Chinese MedicineShanghai 210000China

BACKGROUND Massive intragastric clotting(MIC) makes endoscopic therapy difficult in patients with acute upper gastrointestinal bleeding. Literature data on how to address this problem are limited. Here, we report on a case of massive stomach bleeding with MIC that was successfully treated endoscopically using an overtube of singleballoon *** SUMMARY A 62-year-old gentleman with metastatic lung cancer was admitted to the intensive care unit due to tarry stools and hematemesis of 1500 mL of blood during hospitalization. Emergent esophagogastroduodenoscopy revealed massive blood clots and fresh blood in the stomach with evidence of active *** sites could not be observed even by changing the patient’s position and aggressive endoscope suction. The MIC was successfully removed using an overtube connected with a suction pipe, which was inserted into the stomach with an overtube of a single-balloon enteroscope. An ultrathin gastroscope was also introduced through the nose into the stomach to guide the suction. A massive blood clot was successfully removed, and an ulcer with oozing bleeding at the inferior lesser curvature of the upper gastric body was revealed, facilitating endoscopic hemostatic *** This technique appears to be a previously unreported method to suction MIC out of the stomach in patients with acute upper gastrointestinal bleeding. This technique could be considered when other methods are not available or if they fail to remove massive blood clots in the stomach.

关键词： Upper gastrointestinal bleeding Massive intragastric clotting Overtube for single-balloon enteroscope Ultrathin gastroscope Case report

Effect of astrocyte on synchronization of thermosensitive neuron–astrocyte minimum system

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Chinese Physics B 2022年第8期31卷 325-336页

作者： yi-Xuan shan Hui-Lan Yang Hong-Bin Wang Shuai Zhang ying Li Gui-Zhi Xu State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjin 300130China Hebei Key Laboratory of Bioelectromagnetics and Neural Engineering Hebei University of TechnologyTianjin 300130China

Astrocytes have a regulatory function on the central nervous system(CNS), especially in the temperature-sensitive hippocampal region. In order to explore the thermosensitive dynamic mechanism of astrocytes in the CNS, we establish a neuron-astrocyte minimum system to analyze the synchronization change characteristics based on the Hodgkin-Huxley model, in which a pyramidal cell and an interneuron are connected by an astrocyte. The temperature range is set as 0-40 ℃ to juggle between theoretical calculation and the reality of a brain environment. It is shown that the synchronization of thermosensitive neurons exhibits nonlinear behavior with changes in astrocyte parameters. At a temperature range of0 ℃-18 ℃, the effects of the astrocyte can provide a tremendous influence on neurons in synchronization. We find the existence of a value for inositol triphosphate(IP_(3)) production rate and feedback intensities of astrocytes to neurons, which can ensure the weak synchronization of two neurons. In addition, it is revealed that the regulation of astrocytes to pyramidal cells is more sensitive than that to interneurons. Finally, it is shown that the synchronization and phase transition of neurons depend on the change in Ca^(2+) concentration at the temperature of weak synchronization. The results in this paper provide some enlightenment on the mechanism of cognitive dysfunction and neurological disorders with astrocytes.

关键词： astrocytes synchronization Hodgkin–Huxley model thermosensitive neuron

Hydrological characteristics and changes in the Nu-Salween River basin revealed with model-based reconstructed data

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Journal of Mountain Science 2021年第11期18卷 2982-3002页

作者： YANG Fan LU Hui YANG Kun HUANG Guang-wei LI yi-shan WANG Wei LU Ping TIAN Fu-qiang HUANG Yu-gang Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Ministry of Education Ecological Field Station for East Asian Migratory Birds Beijing 100084China Center for Excellence in Tibetan Plateau Earth Sciences and National Tibetan Plateau Data Center Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China Graduate School of Global Environmental Studies Sophia UniversityTokyo 102-8554Japan Changjiang Institute of Survey PlanningDesign and ResearchWuhan 430010China Department of Hydraulic Engineering State Key Laboratory of Hydroscience and EngineeringTsinghua UniversityBeijing 100084China The International Economic&Technical Cooperation and Exchange Center Ministry of Water ResourcesBeijing 100053China

The Nu-Salween River(NSR),the longest free-flow river in Southeast Asia,plays an irreplaceable role in social development and ecological *** lower NSR region is particularly valuable as it is inhabited by approximately 6.7 million *** basin has limited hydraulic conservancy infrastructure and insufficient ability to cope with climate change *** the hydrological characteristics and changes in the basin provides the scientific basis for rational protection and development of the ***,owing to the limitation of observation data,previous studies have focused on the local area and neglected the study of the lower reaches,which is not enough to reflect the spatial characteristics of the entire *** this study,the ECMWF 5th generation reanalysis data(ERA5)and Multi-Source Weighted-Ensemble Precipitation(MSWEP)were applied to develop a geomorphology-based hydrological model(GBHM)for reconstructing hydrological datasets(***-ERA5 and GBHM-MSWEP).The reconstructed datasets covering the complete basin were verified against the gauge observation and compared with other commonly used streamflow products,including Global Flood Awareness System v2.1,GloFAS-Reanalysis dataset v3.0,and linear optimal runoff aggregate(LORA).The comparison results revealed that GBHM-ERA5 is significantly better than the other four datasets and provides a good reproduction of the hydrological characteristics and trends of the *** analysis of GBHM-ERA5 revealed that:(1)A multi-year mean surface runoff represented 39%of precipitation over the basin during 1980–2018,which had low surface runoff in the upstream,while areas around the Three Parallel Rivers Area and the estuary had abundant surface runoff.(2)The surface runoff and discharge coefficient of variations in spring were larger than those in other seasons,and the inter-annual variation in the downstream was smaller than that in the upstream and midstream regions.(3)More than 70%of the basin are

关键词： Nu-Salween River Distributed hydrologic model ERA5 Surface runoff Discharge Climate Change

Analytical solution of coal-bed methane migration with slippage effects in hypotonic reservoir

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Journal of Coal Science & Engineering(China) 2011年第2期17卷 137-141页

作者： XIAO Xiao-chun PAN yi-shan YU Li-yan JIANG Chun-yu School of Mechanics and Engineering Liaoning Technical University Fuxin 123000 China

Using theoretical analysis, the single-phase gas seepage mathematical model influenced by slippage effects was established. The results show that the pressure of producing wells attenuates more violently than the wells without slippage effects. The decay rate of reservoir pressure is more violent as the Klinkenherg factor increases. The gas prediction output gradually increases as the Klinenberg factor increases when considering gas slippage effects. Through specific examples, analyzed the law of stope pore pressure and gas output forecast changing in a hypotonic reservoir with slippage effects. The results have great theoretical significance in the study of the law of coal-bed methane migration in hypotonic reservoirs and for the exploitation of coal-bed methane.

关键词： slippage effect hypotonic reservoir Klinkenberg factor analysis solution