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Creep Behavior and Life Assessment of a Novel Heat-Resistant Austenite Steel and Its Weldment

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Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 638-650页

作者： Yu Zhang Hong-yang Jing Lian-Yong xu Yong-dian Han Lei Zhao Xi-Shan Xie Qiu-Hua Zhu School of Materials Science and Engineering Tianjin University Tianjin Key Laboratory of Advanced Joining Technology School of Materials Science and Engineering University of Science and TechnologyBeijing Jiangsu Wujin Stainless Steel Pipe Group Co. Ltd

In the present study, creep activation energy for rupture was obtained as 221-348 kJ/mol for 22Cr15Ni3.5 CuNbN due to the precipitation-hardening mechanism. The extrapolation strength of creep rupture time of 10~5 h at 923 K for22 Cr15 Ni3.5 CuNbN is more valid(83.71 MPa) predicted by the Manson-Haferd method, which is superior to other commercial heat-resistant steels. The tensile creep tests ranging from 180 to 240 MPa at 923 K were conducted to investigate creep deformation behavior of welded joint between a novel heat-resistant austenite steel 22Cr15Ni3.5 CuNbN and ERNiCrCoMo-1 weld metal. Apparent stress exponent value of 6.54 was obtained, which indicated that the ratecontrolled creep occurred in weldment during creep. A damage tolerance factor of 6.4 in the weldment illustrates that the microstructural degradation is the dominant creep damaging mechanism in the alloy. Meanwhile, the welded joints perform two types of deformation behavior with the variation in applied stress, which resulted from the different parts that govern the creep processing. Also, the morphology evolution of the fracture surfaces confirms the effects of stress level and stress state.

关键词： Heat-resistant steel weldment Creep deformation Life assessment TTP(time–temperature parametric) method

New analytic solutions to 2D transient heat conduction problems with/without heat sources in the symplectic space

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Applied Mathematics and Mechanics(English Edition) 2022年第8期43卷 1233-1248页

作者： dian xu Xinran ZHENG Dongqi AN Chao ZHOU Xiuwen HUANG Rui LI State Key Laboratory of Structural Analysis for Industrial Equipment Department of Engineering Mechanicsand International Research Center for Computational MechanicsDalian University of TechnologyDalianLiaoning Province116024China

The two-dimensional(2D)transient heat conduction problems with/without heat sources in a rectangular domain under different combinations of temperature and heat flux boundary conditions are studied by a novel symplectic superposition method(SSM).The solution process is within the Hamiltonian system framework such that the mathematical procedures in the symplectic space can be implemented,which provides an exceptional direct rigorous derivation without any assumptions or predetermination of the solution forms compared with the conventional inverse/semi-inverse *** distinctive advantage of the SSM offers an access to new analytic heat conduction *** results obtained by the SSM agree well with those obtained from the finite element method(FEM),which confirms the accuracy of the SSM.

关键词： heat conduction heat source symplectic superposition method(SSM)

Construction of a sustainable 3-hydroxybutyrate-producing probiotic Escherichia coli for treatment of colitis

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Cellular & Molecular Immunology 2021年第10期18卷 2344-2357页

作者： xu Yan Xin-Yi Liu dian Zhang Yu-dian Zhang Zi-Hua Li xu Liu Fuqing Wu Guo-Qiang Chen Center for Synthetic and Systems Biology Tsinghua UniversityBeijingChina School of Life Sciences Tsinghua UniversityBeijingChina MOE Key Lab for Industrial Biocatalysis Dept.Chemical EngineeringTsinghua UniversityBeijingChina

Colitis is a common disease of the colon that is very difficult to *** bacteria could be an effective *** probiotic Escherichia coli Nissle 1917(EcN)was engineered to synthesize the ketone body(R)-3-hydroxybutyrate(3HB)for sustainable production in the gut lumen of mice suffering from *** of heterologous 3HB synthesis routes were constructed,expressed,optimized,and inserted into the EcN genome,combined with deletions in competitive branch *** genome-engineered EcN produced the highest 3HB level of 0.6 g/L under microaerobic *** live therapeutic was found to colonize the mouse gastrointestinal tract over 14 days,elevating gut 3HB and short-chain-length fatty acid(SCFA)levels 8.7-and 3.1-fold compared to those of wild-type EcN,*** sustainable presence of 3HB in mouse guts promoted the growth of probiotic bacteria,especially Akkermansia spp.,to over 31%from the initial 2%of all the *** a result,the engineered EcN termed EcNL4 ameliorated colitis induced via dextran sulfate sodium(DSS)in *** to wild-type EcN or oral administration of 3HB,oral EcNL4 uptake demonstrated better effects on mouse weights,colon lengths,occult blood levels,gut tissue myeloperoxidase activity and proinflammatory cytokine ***,a promising live bacterium was developed to improve colonic microenvironments and further treat *** proof-of-concept design can be employed to treat other diseases of the colon.

关键词： Escherichia coli Nissle 1917 Colitis β-hydroxybutyrate 3HB Synthetic biology Metabolic engineering Microbiomes Probiotics Colonic microenvironment

Effect of Nb and Mo on the Microstructure, Mechanical Properties and Ductility-Dip Cracking of Ni–Cr–Fe Weld Metals

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Acta Metallurgica Sinica(English Letters) 2016年第10期29卷 928-939页

作者： xu Zhang dian-Zhong Li Yi-Yi Li Shan-Ping Lu Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences

A series of Ni-Cr-Fe welding wires with different Nb and Mo contents were designed to investigate the effect of Nb and Mo on the rnicrostructure, mechanical properties and the ductility-dip cracking susceptibility of the weld metals by optical microscopy （OM）, scanning electron microscopy, X-ray diffraction as well as the tensile and impact tests. Results showed that large Laves phases formed and distributed along the interdendritic regions with high Nb or Mo addition. The Cr-carbide （M23C6） was suppressed to precipitate at the grain boundaries with high Nb addition. Tensile testing indicates that the ultimate strength of weld metals increases with Nb or Mo addition. However, the voids formed easily around the large Laves phases in the interdendritic area during tensile testing for the weld metal with high Mo content. It is found that the tensile fractographs of high Mo weld metals show a typical feature of interdendritic fracture. The high Nb or Mo addition, which leads to the formation of large Laves phases, exposes a great weakening effect on the impact toughness of weld metals. In addition, the ductility-dip cracking was not found by OM in the selected cross sections of weld metals with different Nb additions. High Nb addition can eliminate the ductility-dip cracking from the Ni-Cr-Fe weld metals effectively.

关键词： Nb Mo Laves phase Microstructure Mechanical properties

Evolutionary Optimization Methods for High-Dimensional Expensive Problems:A Survey

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1092-1105页

作者： MengChu Zhou Meiji Cui dian xu Shuwei Zhu Ziyan Zhao Abdullah Abusorrah Department of Electrical and Computer Engineering New Jersey Institute of TechnologyNewarkNJ 07102 USA School of Information and Electronic Engineering Zhejiang Gongshang UniversityHangzhou 310018China School of Intelligent Manufacturing Nanjing University of Science and TechnologyNanjing 210094China Institute of Systems Engineering Macao University of Science and TechnologyMacao 999078China School of Artificial Intelligence and Computer Jiangnan UniversityWuxi 214122China School of Information Science and Engineering Northeastern UniversityShenyang 110819China Center of Research Excellence in Renewable Energy and Power Systems Department of Electrical and Computer EngineeringFaculty of EngineeringKing Abdulaziz UniversityJeddah 21589Saudi Arabia K.A.CARE Energy Research and Innovation Center King Abdulaziz UniversityJeddah 21589Saudi Arabia

Evolutionary computation is a rapidly evolving field and the related algorithms have been successfully used to solve various real-world optimization *** past decade has also witnessed their fast progress to solve a class of challenging optimization problems called high-dimensional expensive problems(HEPs).The evaluation of their objective fitness requires expensive resource due to their use of time-consuming physical experiments or computer ***,it is hard to traverse the huge search space within reasonable resource as problem dimension *** evolutionary algorithms(EAs)tend to fail to solve HEPs competently because they need to conduct many such expensive evaluations before achieving satisfactory *** reduce such evaluations,many novel surrogate-assisted algorithms emerge to cope with HEPs in recent *** there lacks a thorough review of the state of the art in this specific and important *** paper provides a comprehensive survey of these evolutionary algorithms for *** start with a brief introduction to the research status and the basic concepts of ***,we present surrogate-assisted evolutionary algorithms for HEPs from four main *** also give comparative results of some representative algorithms and application ***,we indicate open challenges and several promising directions to advance the progress in evolutionary optimization algorithms for HEPs.

关键词： computer optimization evolutionary

Sintered Ore Sprayed by Acid and Alkaline Waste Water Resulted From Cold Rolling

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Journal of Iron and Steel Research International 2013年第3期20卷 36-38页

作者： yang Da-zheng QI dian-wei xu Peng-fei ZHANG Da-kui MA Guang-yu LI Jing Technology Center of Angang Anshan Iron and Steel Co.Ltd. School of Material and Metallurgy University of Science and Technology Liaoning

In order to prevent the powdering of a sintered ore from influencing the smooth operation of a blast furnace,the conventional way to deal with it is that the CaCl2 solution is prepared by tap water,and then the solution is sprayed onto the sintered ore for improving its RDI（low temperature reduction degradation index）.The CaCl2 solution prepared by adding acid and alkaline waste water resulted from cold rolling is sprayed onto the sintered ore to improve its *** values of RDI＋6.3 and RDI＋3.15 of the sintered ore which is sprayed by the CaCl2 solution with the CaCl2 concentration of 3.5%（mass percent） are increased by 17.5% and 11.63%,but the index of RDI-0.5 is decreased by 3.1% when the spraying amount of the solution is making up 0.5% of the total sintered ore sprayed in comparison with those of the sintered ore which is not sprayed by using the CaCl2 *** results show that after the CaCl2 solutions prepared by adding the acid and alkaline waste water are sprayed on the sintered ore,RDI of the ore can be remarkably improved and therefore another way for recycling acid and alkaline waste water can be available,by which both cost for treating waste water and cost for producing a sintered ore can be decreased and environment is free of pollution by harmful substances in the waste water.

关键词： waste water sintered ore low temperature reduction degradation index(RDI)

Combined hepatocellular carcinoma and cholangiocarcinoma:a case report and review of the literature

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Hepatobiliary & Pancreatic Diseases International 2007年第6期6卷 656-659页

作者： Zhou, Yan-Ming yang, Jia-Mei Wang, Bin xu, Feng Tong, Ying Li, dian-Qi Mil Med Univ 2 Eastern Hepatobiliary Surg Hosp Dept Special Treatment Shanghai 200438 Peoples R China Mil Med Univ 2 Eastern Hepatobiliary Surg Hosp Dept Pathol Shanghai 200438 Peoples R China

BACKGROUND: combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC) is a rare histopathologic form of primary liver cancer. We report a case of cHCC-CC and review the literature. METHOD: The clinicopathological features of a 61-year-old male were retrospectively analyzed. RESULTS: Hepatocellular carcinoma (HCC) was preoperatively considered on the basis of clinical findings resembling those associated with HCC. Hepatectomy was therefore performed. Microscopically, the specimen displayed histological features of cHCC-CC. The patient has remained alive after follow-up for 3 months without evidence of recurrence and metastasis. CONCLUSION: It is difficult to make a correct preoperative diagnosis of cHCC-CC and hepatic resection is the treatment of choice.

关键词： combined hepatocellular carcinoma and cholangiocarcinoma hepatectomy

Effect of Initial Crown on Shape of Hot Rolled Strip

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Journal of Iron and Steel Research International 2009年第5期16卷 32-34页

作者： HU Yu GONG dian-yao JIANG Zheng-yi xu Jian-zhong ZHANG dian-hua LIU Xiang-hua State Key Laboratory of Rolling Technology and Automation Northeastern University Shenyang 110004 Liaoning China AriTime Co Ltd Beijing 100070 China Faculty of Engineering University of WoUongong Wollongong NSW 2522 Australia

Based on the influence coefficient method, the effect of entry strip crown on the shape of hot rolled strip was analyzed using the software of roll elastic deformation simulation. According to the practical condition of a domestic hot rolled strip plant, the unit strip crown change from the first stand to the last stand was calculated when the entry crown of hot strip varies. The calculated result shows that the entry strip crown does not significantly affect the target strip crown at the exit of the last finishing stand in respect to a fixed strip shape control reference （such as bending force）. The calculation was analyzed, and the research is helpful in modeling strip shape setup and shape control.

关键词： influence coefficient method strip crown crown effect rate hot rolled strip

Effect of Different Raft Shapes on Hydrodynamic Characteristics of the Attenuator-Type Wave Energy Converter

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China Ocean Engineering 2023年第4期37卷 645-659页

作者： WANG Jin WANG Shu-qi JIANG Qing-dian xu Yun-xin SHI Wei-chao School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Department of Naval Architecture Ocean and Marine EngineeringUniversity of StrathclydeGlasgowG40LZUK

A numerical simulation method based on CFD has been established to simulate the fully coupled motion for an atten-uator-type wave energy converter(WEC).Based on this method,a detailed parametric analysis has been conducted to investigate the design of the *** effects of different parameters(wave parameters,structural parameters and PTO parameters)on the hydrodynamic characteristics of the attenuator-type WEC were studied in *** results show that in terms of wave parameters,there is an optimal wave period,which makes the relative pitching angle amplitude of the WEC reach the maximum,and the increase of wave height is conducive to the relative pitching angle amplitude of wave *** different wave conditions,the relative pitch angle of the parallelogram raft device is the *** terms of structural parameters,the parallelogram attenuator-type device has the optimal values in different relative directions,different distances and different apex angle,which makes the relative motion amplitude of the device reach the maximum,and the spacing and the apex angle have influence on the motion frequency of the device,while the relative direction has almost no influence on *** terms of PTO parameters,there is an optimal damping coefficient,which makes the power generation efficiency of the WEC reach the *** research results provide a valuable reference for future research and design of the attenuator-type WEC.

关键词： wave energy converter attenuator-type shape hydrodynamic analysis power generation efficiency