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High-performance chromite by structure stabilization treatment

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Journal of Iron and Steel Research International 2020年第2期27卷 169-179页

作者： En-hui Wang Chang Luo jun-hong chen Xin-mei Hou Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China

Chromite is an important raw material applied in *** have been made to obtain high-performance chromite by adding MgO and Al203 from the viewpoint of structure *** order to explore the effect of Al203 and MgO on the structure,two formulas,i.e.,Mg-rich and Al-rich ones,were *** phase and microstructure development of samples heated in the temperature range of 1200-1600℃ were studied by X-ray diffraction and scanning electron microscopy with energy-dispersive *** and Al203 added have diffused into chromite successfully by heat *** diffuses into chromite,occupying the tetrahedral vacancies caused by the diffusion and oxidation of Fe2+ions to stabilize the ***203 diffuses into the surface layer of chromite,forming spinel-sesquioxide ***-rich sample which has spinel-sesquioxide structure shows better corrosion resistance toward fayalite slag than Mg-rich sample which has single spinel structure by blocking the interdiffusion between Fe^2+ions in fayalite slag and Mg^2+ions in chromite.

关键词： Chromite Structure optimization Corrosion resistance Refractory

Scalable connection-based flow control scheme for application-specific network-on-chip

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The Journal of China Universities of Posts and Telecommunications 2011年第6期18卷 98-105页

作者： LIN Shi-jun SHI Jiang-hong chen Hui-huang School of Information Science and Technology Xiamen University Xiamen 361005 China

In this paper, a scalable connection-based flow control scheme is proposed for application-specific network-on-chip （NoC）. The proposed scheme exploits two distinctive characteristics of NoC, namely traffic predictability and abundant wire resource, to achieve significant performance enhancements. First, the burst injection data are regulated into constant data streams and a connection-based method is used to ensure that all links are not overloaded at any time. Consequently, the number of packets in the network is decreased, leading to a reduced congestion probability and improved communication performance. Second, a simple architecture of the central controller is proposed to guarantee that the proposed scheme has small area overhead and is scalable. Simulation results show that compared with traditional switch-to-switch （STS） flow control scheme and pre-allocation based flow control schemes, the proposed scheme greatly increases the throughput and cuts down the average latency with reasonable area and energy overhead.

关键词： network-on-chip (NoC) system-on-chip (SoC) flow control

Rapid Synthesis of Piezoelectric ZnO-Nanostructures for Micro Power-Generators

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Journal of Materials Science & Technology 2013年第10期29卷 893-897页

作者： Nai-Feng Hsu Tien-Kan Chung Ming Chang hong-jun chen Department of General Education Army Academy Department of Mechanical Engineering National Chiao Tung University Department of Mechanical Engineering Chung Yuan Christian University State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology

In this paper, we report a rapid synthesis of piezoelectric ZnO-nanostructures and fabrication of the nanostructures- based power-generators demonstrating an energy conversion from an environmental mechanical/ultrasonic energy to an electrical energy. The ZnO nanostructures are grown on a silicon wafer by a modified chemical solution method （CSD, chemical-solution-deposition） with a two-step thermal-oxidation approach. The synthesis process can be completed within 1 h. By varying the mixture-ratio of Zn micro-particles in an oxalic acid solution with 0.75 mol/l concentration in the CSD process, the growth mechanism is well-controlled to synthesize three different types of ZnO-nanostructures （i.e., dandelion-like nanostructures, columnar nanostructures, and nanowires）. Furthermore, through oxidizing at different temperatures in the thermal-oxidation process, the featured geometry of the nanostructures （e.g., the length and diameter of a nanowire） is modified. The geometry, size, morphology, crystallization, and material phase of the modified nanostructures are characterized by scanning electron microscopy and X-ray diffraction. Finally, the nanostructures are used to fabricate several micro power-generators. Through the piezoelectric effect, a maximum current density output of 0.28 μA cm-2 generated by a power-generator under an ultrasonic wave is observed.

关键词： Piezoelectric ZnO nanostructures Chemical solution method Thermal-oxidation Power-generator

Utility of multiple endoscopic techniques in differential diagnosis of gallbladder adenomyomatosis from gallbladder malignancy with bile duct invasion: A case report

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World Journal of Clinical Cases 2020年第2期8卷 464-470页

作者： Li-Jia Wen jun-hong chen Yong-Jin chen Kai Liu Department of Hepatopancreatobiliary Surgery The First Hospital of Jilin University

BACKGROUND Gallbladder adenomyomatosis(GAM) is a benign lesion, characterized by thickening of the gallbladder wall and a focal mass, which overlap with the features of gallbladder malignancy. Consequently, differential diagnosis of GAM from gallbladder cancer is difficult and approximately 20% of suspected malignant biliary strictures are postoperatively confirmed as benign ***, we report a case in which a preoperative diagnosis of GAM was made by a combination of endoscopic and imaging *** SUMMARY A 40-year-old man was referred to our hospital chiefly for a fever and right upper abdominal pain with dark urine. Enhanced computed tomography showed thickening of the gallbladder wall and a mass in the gallbladder neck with involvement of the hepatic bile ducts, which was suspected to be *** malignancy with bile duct invasion was ruled out by subsequent endoscopic examinations, including endoscopic retrograde cholangiopancreatography, intraductal ultrasound, and Spy Glass. Endoscopic examinations showed a homogeneous hyperechoic lesion with smooth margins of benign bile duct stricture suggestive of inflammatory stenosis of the bile *** patient underwent laparoscopic cholecystectomy. GAM was postoperatively diagnosed and confirmed based on the histopathology results, which are consistent with the preoperative diagnosis. Notably, no malignant event occurred in the patient during a 12-mo follow-up *** A combination of endoscopic techniques may help in the differential diagnosis of GAM from gallbladder cancer.

关键词： Gallbladder adenomyomatosis Differential diagnosis Endoscopic retrograde cholangio-pancreatography Intraductal ultrasound SpyGlass Case report

Severe acute pancreatitis in the elderly: Etiology and clinical characteristics

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World Journal of Gastroenterology 2008年第16期14卷 2517-2521页

作者： Ming-jun Xin hong chen Bin Luo Jia-Bang Sun Department of General Surgery Xuanwu Hospital Capital Medical University Beijing 100053 China

AIM: To investigate the etiology and clinical characteristics of severe acute pancreatitis (SAP) in elderly patients (≥ 60 years of age). METHODS: We reviewed retrospectively all the SAP cases treated in Xuanwu Hospital in Beijing between 2000 and 2007. RESULTS: In 169 patients with SAP, 94 were elderly and 16 died. Biliary and idiopathic etiologies were the first two causes that accounted for over 90% of SAP in the elderly. Biliary, hyperlipemic and alcoholic etiologies were the first three causes in the young. The proportion of co- morbidity of cholelithiasis, biliary infection, hypertension and coronary heart disease in the aged was significantly higher than that in their young partners. The scores of APACHE Ⅱ and Ranson were also significantly higher in the elderly except the CT score. Organ failures were more common in the elderly, but the local pancreatic complications were not different between the two groups. Mortality of the aged was correlated with the severity of SAP, multiple co-morbidity and incidence of multiple organ dysfunction syndrome (MODS). MODS was the main cause of death. CONCLUSION: The etiology of SAP in the elderly is quite different from that in the young. Biliary and unknown factors are main causes in the aged. The elderly are subject to major organ failures but there is no difference in the occurrence of local pancreatic complications between the elderly and the young. It is crucial to monitor and improve the functions of major organs so as to prevent MODS in the aged with SAP.

关键词： Severe acute pancreatitis Elderly Etiology Mortality Complication

Microwave absorption properties of SiC@SiO2@Fe3O4 hybrids in the 2–18 GHz range

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International Journal of Minerals,Metallurgy and Materials 2017年第7期24卷 804-813页

作者： Peng Zhou jun-hong chen Meng Liu Peng Jiang Bin Li Xin-mei Hou National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 China School of Material Science and Engineering University of Science and Technology Beijing Beijing 100083 China Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing Beijing 100083 China

To enhance the microwave absorption performance of silicon carbide nanowires（SiCNWs）, SiO_2 nanoshells with a thickness of approximately 2 nm and Fe_3O_4 nanoparticles were grown on the surface of SiCNWs to form SiC@SiO_2@Fe_3O_4 hybrids. The microwave absorption performance of the SiC@SiO_2@Fe_3O_4 hybrids with different thicknesses was investigated in the frequency range from 2 to 18 GHz using a free-space antenna-based system. The results indicate that SiC@SiO_2@Fe_3O_4 hybrids exhibit improved microwave absorption. In particular, in the case of an SiC@SiO_2 to iron（III） acetylacetonate mass ratio of 1：3, the microwave absorption with an absorber of 2-mm thickness exhibited a minimum reflection loss of-39.58 d B at 12.24 GHz. With respect to the enhanced microwave absorption mechanism, the Fe_3O_4 nanoparticles coated on SiC@SiO_2 nanowires are proposed to balance the permeability and permittivity of the materials, contributing to the microwave attenuation.

关键词： silicon carbide nanowires hybrids microwave absorption mechanism impedance match

Reaction behavior of trace oxygen during combustion of falling FeSi75 powder in a nitrogen flow

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International Journal of Minerals,Metallurgy and Materials 2016年第8期23卷 959-965页

作者： Bin Li jun-hong chen Peng Jiang Ming-wei Yan Jia-lin Sun Yong Li School of Materials Science and Engineering University of Science and Technology Beijing

To explore the reaction behavior of trace oxygen during the flash combustion process of falling FeSi75 powder in a nitrogen flow, a flash-combustion-synthesized Fe-Si;N;sample was heat-treated to remove SiO;. The samples before and after the treatment were investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, and the formation mechanism of SiO;was investigated. The results show that SiO;in the Fe-Si;N;is mainly located on the surface or around the Si;N;particles in dense areas, existing in both crystalline and amorphous states; when the FeSi75 particles, which are less than 0.074 mm in size, fell in up-flowing hot N;stream, trace oxygen in the N;stream did not significantly hinder the nitridation of FeSi75 particles as it was consumed by the surface oxidation of the generated Si;N;particles to form SiO;. At the reaction zone, the oxidation of Si;N;particles decreased the oxygen partial pressure in the N;stream and greatly reduced the opportunity for FeSi75 particles to be oxidized into SiO;; by virtue of the SiO;film developed on the surface, the Si;N;particles adhered to each other and formed dense areas in the material.

关键词： silicon nitride combustion synthesis oxygen atmosphere

Morphology characterization of periclase–hercynite refractories by reaction sintering

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International Journal of Minerals,Metallurgy and Materials 2015年第11期22卷 1219-1224页

作者： Peng Jiang jun-hong chen Ming-wei Yan Bin Li Jin-dong Su Xin-mei Hou School of Materials Science and Engineering University of Science and Technology Beijing Collaborative Innovation Center of Steel Technology University of Science and Technology Beijing

A periclase？hercynite brick was prepared via reaction sintering at 1600℃for 6 h in air using magnesia and reaction-sintered hercynite as raw materials. The microstructure development of the periclase-hercynite brick during sintering was investigated using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy in combination with energy-dispersive X-ray spectroscopy. The results show that during sintering, Fe^2＋, Fe^3＋ and Al^3＋ ions in hercynite crystals migrate and react with periclase to form（Mg1-xFex）（Fe2-yAly）O4 spinel with a high Fe/Al ratio. Meanwhile, Mg^2＋ in periclase crystals migrates into hercynite crystals and occupies the oxygen tetrahedron vacancies. This Mg^2＋ migration leads to the formation of（Mg1-uFeu）（Fe2-vAlv）O4 spinel with a lower Fe/Al ratio and results in Al3＋ remaining in hercynite crystals. Cation diffusion between periclase and hercynite crystals promotes the sintering process and results in the formation of a microporous structure.

关键词： refractories periclase hercynite sintering morphology diffusion

Morphology of α-Si_3N_4 in Fe–Si_3N_4 prepared via flash combustion

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International Journal of Minerals,Metallurgy and Materials 2015年第12期22卷 1322-1327页

作者： Bin Li jun-hong chen Jin-dong Su Ming-wei Yan Jia-lin Sun Yong Li School of Materials Science and Engineering University of Science and Technology Beijing

The state and formation mechanism of α-Si3N4 in Fe-Si3N4 prepared by flash combustion were investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results indicate that α-SiaN4 crystals exist only in the Fe-Si3N4 dense areas. When FeSi75 particles react with N2, which generates substantial heat, a large number of Si solid particles evaporate. The product between Si gas and N2 is a mixture of α-Si3N4 and β-Si3N4. At the later stage of the flash combustion process, α-Si3N4 crystals dissolve and reprecipitate as α-Si3N4 and the β-Si3N4 crystals grow outward from the dense areas in the product pool. As the temperature decreases, the α-SiaN4 crystals cool before transforming into β-SiaN4 crystals in the dense areas of Fe-Si3N4. The phase composition of flash-combustion-synthesized Fe-SiaN4 is controllable through manipulation of the gas-phase reaction in the early stage and the α→β transformation in the later stage.

关键词： silicon nitride combustion synthesis morphology crystal growth