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Simultaneously tuning structural defects and crystal phase in accordion-like Ti_(x)O_(2x−1)derived from Ti_(3)C_(2)T_(x)MXene for enhanced electromagnetic attenuation

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Journal of Advanced Ceramics 2023年第10期12卷 1946-1960页

作者： Yang Li Yuchang Qing Yuerui Zhang Hailong Xu State Key Laboratory of Solidification processing School of Material Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

Single Ti_(3)C_(2)T_(x)MXene(MTO)materials are not suitable for electromagnetic(EM)wave absorption due to their high conductivity and impedance *** address this issue,we ingeniously took advantage of easily oxidized characteristics of Ti_(3)C_(2)T_(x)MXene to establish structural defects and multiphase engineering in accordion-like TixO_(2x−1)derived from Ti_(3)C_(2)T_(x)MXene by a high-temperature hydrogen reduction process for the first *** evolution sequences are revealed to be Ti_(3)C_(2)T_(x)MXene/anatase TiO_(2)→Ti_(3)C_(2)T_(x)MXene/rutile TiO_(2)→TixO_(2x−1)(1≤x≤4)during a hydrogen reduction *** from conductance loss caused by hole motion under the action of an external electric field and heterointerfaces caused by interfacial polarization,the impedance match and EM attenuation capability of accordion-like TixO_(2x−1)absorbers derived from Ti_(3)C_(2)T_(x)MXene are superior to that of pristine Ti_(3)C_(2)T_(x)MXene/TiO_(2)***,simulated whole radar cross section(RCS)plots in different incident angular of the Ti_(3)C_(2)T_(x)MXene/rutile TiO_(2)product are lower than−20 dBm^(2),and the minimum RCS value can reach−43 dBm^(2),implying a great potential for practical applications in the EM wave ***,the relationship among charges,defects,interfaces,and EM performances in the accordion-like TixO_(2x−1)materials is systematically clarified by the energy band theory,which is suitable for the research of other MXene-derived semiconductor absorbing composites.

关键词： semiconductor oxygen defects multiphase engineering energy band microwave absorption

Corner forming of AZ61A magnesium alloy tube within warm hydroforming

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Journal of Harbin Institute of Technology(New Series) 2009年第2期16卷 227-231页

作者：胡蓝韩聪何祝斌汤泽军刘钢苑世剑 National Key Laboratory of Precision Hot processing of Metals Harbin Institute of Technology

The comers with small radii on cross sections are crucial for forming hydroformed components with polygonal sections. In this paper, warm hydroforming experiments of AZ61A magnesium alloy tubes were cartied out to study the forming regularity of round comers by using a demonstration part with square sections. Effects of temperature on radius forming, thinning ratio distribution and microstructure were revealed and a component with relative outer corner radius of 3.0 was obtained by warm hydroforming at 240℃. The minimum thickness of the formed square section was located in the transition position between the corner and the straight wall. The thinning ratio of the round corner increased with the increase of forming temperature. Fotmability of the magnesium tube was improved by raising temperature under the effect of dynamic recrystallization at 240℃.

关键词： warm hydroforming magnesium alloy thickness distribution

Vertical section phase diagrams of La−Fe−B ternary system

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Transactions of Nonferrous Metals Society of China 2021年第6期31卷 1748-1757页

作者： Qi WEI Zhao LU Qing-rong YAO Jian-qiu DENG Jiang WANG Huai-ying ZHOU Guang-hui RAO Guangxi Key Laboratory of Information materials School of Materials Science and EngineeringGuilin University of Electronic TechnologyGuilin 541004China School of Physical Science and Technology Guangxi UniversityNanning 530004China Guangxi Key Laboratory of processing for Non-ferrous Metals and Featured materials Nanning 530004China

The vertical sections of the La−Fe−B system were investigated using electron probe microanalysis and differential thermal *** on the microstructures and phase compositions of the as-cast and equilibrium alloys,together with their heat flow−temperature curves,phase diagrams for three vertical sections were drawn:La_(x)Fe_(82)B_(y)(x+y=18),La_(x)Fe_(70)B_(y)(x+y=30)and La_(x)Fe_(53)B_(y)(x+y=47),where x and y represent mass fraction of La and B,respectively,%.Additionally,according to the phase diagrams,the compound La2Fe14B was identified as a stable phase at high *** was found to be stable between 926.2 and 792.6℃;at low temperatures,however,it decomposed into α-La,α-Fe and LaFe_(4)B_(4),according to the reaction La_(2)Fe_(14)B→α-Fe+α-La+LaFe_(4)B_(4).

关键词： solidification characteristics vertical section phase diagram equilibrium alloy high temperature stable compound

Fabrication of fine-grained,high strength and toughness Mg alloy by extrusion−shearing process

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Transactions of Nonferrous Metals Society of China 2021年第3期31卷 666-678页

作者： Bo-ning WANG Feng WANG Zhi WANG Zheng LIU Ping-li MAO School of materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Key Laboratory of Magnesium Alloys and processing Technology of Liaoning Province Shenyang 110870China

A novel extrusion-shearing(ES) composite process was designed to fabricate fine-grained, high strength and tough magnesium alloy. The structural parameters of an ES die were optimized by conducting an orthogonal simulation experiment using finite element software Deform-3D, and Mg-3 Zn-0.6 Ca-0.6 Zr(ZXK310) alloy was processed using the ES die. The results show that the optimized structural parameters of ES die are extrusion angle(α) of 90°, extrusion section height(h) of 15 mm and inner fillet radius(r) of 10 mm. After ES at an extrusion temperature and a die temperature of 350 °C, ZXK310 alloy exhibited good ES forming ability, and obvious dynamic recrystallization occurred in the forming area. The grain size decreased from 1.42 μm of extrusion area to 0.85 μm of the forming area. Owing to the pinning of second phase and formation of ultrafine grains, the tensile strength, yield strength and elongation of alloy reached 362 MPa, 289 MPa and 21.7%, respectively.

关键词： Mg−Zn−Ca−Zr alloy extrusion−shearing process die design dynamic recrystallization mechanical properties

Dynamic Organization of Large-scale Functional Brain Networks Supports Interactions Between Emotion and Executive Control

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Neuroscience Bulletin 2024年第7期40卷 981-991页

作者： Haiyang Geng Pengfei Xu Andre Aleman Shaozheng Qin Yue-Jia Luo State Key Laboratory of Cognitive Neuroscience and Learning Beijing Normal UniversityBeijing 100875China Tianqiao and Chrissy Chen Institute for Translational ResearchShanghai 200040China Beijing Key Laboratory of Applied Experimental Psychology National Demonstration Center for Experimental Psychology Education(BNU)Faculty of PsychologyBeijing Normal UniversityBeijing 100875China Center for Neuroimaging Shenzhen Institute of NeuroscienceShenzhen 518107China University of Groningen Department of Biomedical Sciences of Cells and SystemsSection Cognitive NeuroscienceUniversity Medical Center GroningenGroningenThe Netherlands Institute for Neuropsychological Rehabilitation University of Health and Rehabilitation SciencesQingdao 266113China Shenzhen Key Laboratory of Affective and Social Neuroscience Magnetic Resonance ImagingCenter for Brain Disorders and Cognitive SciencesShenzhen UniversityShenzhen 518060China Chinese Institute for Brain Research Beijing 102206China

Emotion and executive control are often conceptualized as two distinct modes of human brain ***,however,is known about how the dynamic organization of large-scale functional brain networks that support flexible emotion processing and executive control,especially their *** amygdala and prefrontal systems have long been thought to play crucial roles in these *** advances in human neuroimaging studies have begun to delineate functional organization principles among the large-scale brain networks underlying emotion,executive control,and their ***,we propose a dynamic brain network model to account for interactive competition between emotion and executive control by reviewing recent resting-state and task-related neuroimaging studies using network-based *** this model,dynamic interactions among the executive control network,the salience network,the default mode network,and sensorimotor networks enable dynamic processes of emotion and support flexible executive control of multiple processes;neural oscillations across multiple frequency bands and the locus coeruleus−norepinephrine pathway serve as communicational mechanisms underlying dynamic synergy among large-scale functional brain *** model has important implications for understanding how the dynamic organization of complex brain systems and networks empowers flexible cognitive and affective functions.

关键词： Dynamic brain network Emotion Executive control Salience network Executive control network Default mode network

PV Solar Yield Applicable Simulator Based on Free Irradiance Data Source:Applied Comprehensive Tool for Solar Engineers

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Energy Engineering 2023年第4期120卷 885-909页

作者： Ahmed Mohamed Ragab Abdelhalim Abdelnaby Zekry Ashraf Yahia Hassan Faculty of Engineering Communication SectionBenha UniversityBenha13511Egypt Faculty of Engineering Communication SectionAin Shams UniversityCairo11566Egypt

Accurate PV system simulators are implemented with expensive software platforms using paid irradiance *** main purpose of this paper is to develop and validate a PV system simulator,beginning with a solar cell parameter extraction model,then test and validate long-termIrradiance data using free online source(Typical Meteorological Year TMY in(PVGIS)European website),and finally building full solar generator simulator to run in working real *** results with Accurate Paid PV simulators(which use theMuneer model)showed good accuracy of the proposed *** flow starts with the Irradiance model’s data processing,then solar cell 5 parameters model data processing(to extract cell parameters),and finally full system *** coding programs in real working conditions are used for *** of solar cell parameter extraction show 99.6%to 99.99%matching with data sheet and cell performance under standard test *** simulation output shows 8%less yearly generated energy compared to the PVGIS 2022 long-term simulation(hourly basis(one-year time)).This is due to incident energy variations(between the years 2016 and 2022)of 4.02%.The novelty of the algorithm is the methodology,as it tests irradiance data on an hourly basis and validates results for a whole continuous ***,the 5-parameter solar cell model is used to be validated in long term analysis,not only STC conditions and could be applied on any PV solar *** algorithm and block diagramused are scalable,modular,and interchangeable with similarmodels to be *** simulator could test severalmethods andmodels in solar pv technology.

关键词： Photovoltaics solar systems solar cell parameters extraction solar simulationmodel irradiancemodels solar yield long term analysis

Service fault tolerance for highly reliable service-oriented systems: an overview

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Science China(Information Sciences) 2015年第5期58卷 7-18页

作者： ZHENG ZiBin LYU Michael Rung Tsong WANG HuaiMin Shenzhen Research Institute The Chinese University of Hong Kong National Laboratory for Parallel & Distributed processing National University of Defense Technology

Service-oriented systems are widely-employed in e-business, e-government, finance, management systems, and so on. Service fault tolerance is one of the most important techniques for building highly reliable service-oriented systems. In this paper, we provide an overview of various service fault tolerance techniques,including sections on fault tolerance strategy design, fault tolerance strategy selection, and Byzantine fault tolerance. In the first section, we introduce the design of static and dynamic fault tolerance strategies, as well as the major problems when designing fault tolerance strategies. After that, based on various fault tolerance strategies, in the second section, we identify significant components from a complex service-oriented system, and investigate algorithms for optimal fault tolerance strategy selection. Finally, in the third section, we discuss a special type of service fault tolerance techniques, i.e., the Byzantine fault tolerance.

关键词： fault tolerance software reliability Web service SOA

Ablation Mechanism of HfC-HfO2Protective Coating for SiC-Coated C/C Composites in an Oxyacetylene Torch Environment

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Journal of materials Science & Technology 2017年第10期33卷 1195-1202页

作者： Yang Yang Kezhi Li Guanxi Liu Zhigang Zhao State Key Laboratory of Solidification processing Carbon/Carbon Composites Research Center Northwestern Polytechnical University Xi'an 710072 China

To prevent the C/C composites from ablation, HfC-HfO2 protective coating was prepared by supersonic atmospheric plasma spraying. The morphology and microstructure of HfC-HfO2 coating were characterized by X-ray diffraction and scanning electron microscopy. The ablation resistance test was carried out by an oxyacetylene torch. The results show that the as-prepared coating is dense with little pinholes and crack free. The elements Hf, C and O were uniformly distributed in the cross-section. After ablation for different time, the mass ablation rate fluctuated along with the change of ablation time. The ablation process of the surface coating could be divided into rapid oxidation and solid state sintering stages. During ablation, an Hf CxOy-HfO2 transitional layer was generated in the coating, which resulted from the active oxidation of Hf C. After cooling, some microcracks were observed on the surface of coating, and the structure of cross-section was broken, which were due to the phase transition of HfO2.

关键词： Carbon/carbon composites Supersonic atmospheric plasma spraying Protective coating Ablation property

CONVERSION OF HEAVY AROMATICS TO LIGHT AROMATICS(HAL) ——Providing Cheap Raw materials for Petroleum processing

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石油学报(石油加工) 2000年第5期16卷 91-93页

作者： GUI Shou xi,WANG Jian wei (Research institute of petroleum processing,SINOPEC,Beijing 100083,China) Research institute of petroleum processing SIN OPEC 北京 100083

A new technology has been developed,which can be used for producing more BTX from C 4 and higher alkyl aromatics containing mainly in cracking gasoline and catalytic reforming as well as by products of disproportionating and isomerizing processes.A catalyst consisting of noble metal and zeolite ZSM 5 has been prepared,which possesses higher activity and stability as well as lower hydrogen consumption. It is found that the reaction temperature,reaction pressure,MHSV and H/HC can influence the reaction results,and the proper reaction conditions have been *** pilot plant test was conducted successfully with 36%～50% of product *** to the results of the pilot plant test,reaction heat was measured and the schematic flow of the process has been proposed,which is expected to be commercialized in China in 2000. Key words:heavy aromatics;light aromatics;catalyst 0 min by *** calibration lines were linear in the range of 0.5～100 mg/L,and the detection limits (S/N=2) were 0.15,0.20 and 0.16 mg/L for o,m,p-diphenol,*** recoveries of these materials ranged from 96 % to 103 %.RSDs ranged from 1.2 % to 2.5 %.

关键词： Catalyst Heavy aromatics Light aromatics