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Effects of different types of twinning on microstructure and mechanical properties of a strongly textured TA2 commercially pure titanium alloy subjected to rolling at ambient and cryogenic temperatures

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Journal of Iron and Steel Research International 2018年第3期25卷 275-281页

作者： Jin-ru Luo xiao song Mao-yin Wang Institute of Materials China Academy of Engineering Physics Mianyang 621908 Sichuan China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083 China

Strongly textured commercially pure titanium alloy TA2 plates with different initial textures have been rolled at cryogenic and ambient temperatures to 4% reduction and then post-annealed at 50℃ for 12 h. Microstructures of the samples were investigated using electron backscatter diffraction. The mechanical property of the sheets was tested via quasi-static uniaxial tensile tests along the rolling direction at room temperature. The effects of initial texture and rolling temperature on twin activity and mechanical property have been investigated. Twinning is very active in TA2 titanium during rolling at either room or cryogenic temperature. {1122} contraction twins can be observed in all the sheets and are the dominant twin mode for the sheets with an initial texture having c-axes parallel to the normal direction （ND）. Extension twins have rarely been seen in sheets having an initial texture with c-axes parallel to ND, but play quite an important role in the sheets having an initial texture with c-axes perpendicular to ND. The initial texture of the sheet is considered to determine the twin mode while the cryogenic rolling temperature is found to increase the numbers of twins. Post-annealing does not change obviously the rolled microstructure. After annealing, the strength decreases and elongation to fracture slightly increases. The cryorolled sample has the better strength with little loss in elongation, and this mechanical enhancement is attributed to massive twinning.

关键词： Titanium Rolling Twin Microstructure Mechanical property

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Interaction of subway LIM vehicle with ballasted track in polygonal wheel wear development

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Acta Mechanica Sinica 2011年第2期27卷 297-307页

作者： Ling Li Xin-Biao xiao Xue-song Jin State Key Laboratory of Traction Power Southwest Jiaotong University 610031 Chengdu China

This paper develops a coupled dynamics model for a linear induction motor （LIM） vehicle and a subway track to investigate the influence of polygonal wheels of the vehicle on the dynamic behavior of the system. In the model, the vehicle is modeled as a multi-body system with 35 degrees of freedom. A Timoshenko beam is used to model the rails which are discretely supported by sleepers. The sleepers are modeled as rigid bodies with their vertical, lateral, and rolling motions being considered. In order to simulate the vehicle running along the track, a moving sleeper support model is introduced to simulate the excitation by the discrete sleeper supporters, in which the sleepers are assumed to move backward at a constant speed that is the same as the train speed. The Hertzian contact theory and the Shen– Hedrick–Elkins’ model are utilized to deal with the normal dynamic forces and the tangential forces between wheels and rails, respectively. In order to better characterize the linear metro system （LMS）, Euler beam theory based on modal superposition method is used to model LIM and RP. The vertical electric magnetic force and the lateral restoring force between the LIM and RP are also taken into consideration. The former has gap-varying nonlinear characteristics, whilst the latter is considered as a constant restoring force of 1 kN. The numerical analysis considers the effect of the excitation due to polygonal wheels on the dynamic behavior of the system at different wear stages, in which the used data regarding the polygonal wear on the wheel tread are directly measured at the subway site.

关键词： Linear induction motor Uneven wear Wheel out of roundness Vehicle-track coupling dynamics

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Technical assessment of synthetic natural gas (SNG) production from agriculture residuals

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Journal of Thermal Science 2013年第4期22卷 359-365页

作者： Guohui song Fei Feng Jun xiao Laihong Shen Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and Environment Southeast University Department of Mechanical Technology Nanjing College of Chemical Technology

This paper presents thermodynamic evaluations of the agriculture residual-to-SNG process by thermochemical conversion, which mainly consists of the interconnected fluidized beds, hot gas cleaning, fluidized bed methanation reactor and Selexol absorption unit. The process was modeled using Aspen Plus soft-ware. The process performances, i.e., CH4 content in SNG~ higher heating value and yield of SNGexergy efficiencies with and without heat recovery, unit power consumption, were evaluated firstly. The results indicate that when the other parameters remain unchanged, the steam-to-biomass ratio at carbon boundary point is the optimal value for the process. Im proving the preheating temperatures of air and gasifying agent is beneficial for the SNG yield and exergy effi ciencies. Due to the effects of COz removal efficiency, there are two optimization objectives for the SNG produc tion process：（I） to maximize CH4 content in SNC or （II） to maximize SNG yield. Further, the comparison among different feedstocks indicates that the decreasing order of SNG yield is： corn stalk 〉 wheat straw 〉 rice straw. The evaluation on the potential of agriculture-based SNG shows that the potential annual production of agriculture re sidual-based SNG could be between 555 108 - 611 108 m3 with utilization of 100% of the available unexplored resources. The agriculture residual-based SNG could play a significant role on solving the big shortfall of China＇s natural gas supply in future.

关键词： synthetic natural gas agriculture residual biomass gasification methanation fluidized bed exergy

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Treg Immunomodulation Contributes to the Anti-atherosclerotic Effects of Huxin Formula in ApoE^(-/-)Mice

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Chinese Journal of Integrative Medicine 2024年第10期30卷 896-905页

作者： ou xiao-min CAI Jing HU xiao-yue ZENG Qiao-huang LAN Tao-hua JIANG Wei The Second Clinical College of Guangzhou University of Chinese Medicine Guangzhou510405China Department of Cardiology Guangdong Provincial Hospital of Chinese Medicinethe Second Affiliated Hospital of Guangzhou University of Chinese MedicineGuangzhou510020China Guangdong Provincial Key Laboratory of Chinese Medicine for Prevention and Treatment of Refractory Chronic Diseases Guangzhou510020China

Objective:To explore the effects of Huxin formula(HXF)in curtailing atherosclerosis and its underlying ***:According to random number table method,24 specific pathogen free male ApoE^(-/-)mice were randomly divided into model group,HXF low-dose(HXF-L)group(8.4 g/kg daily),HXF high-dose(HXF-H)group(16.8 g/kg daily),and pravastatin(8 mg/kg daily)group in ExperimentⅠ(n=6 per group).C57BL/6J mice served as the control group(n=6).ApoE^(-/-)mice in HXF-L,HXF-H,pravastatin groups were fed a Western diet and administered continuously by gavage for 12 weeks,while C57BL/6J mice in the control group were fed conventional lab mouse chow for 12 ***,Tregs were depleted by weekly intraperitoneal injection of purified anti-mouse CD25 antibody(PC61,250μg per mouse)for 4 weeks in ExperimentⅡ(n=6 per group).Oil Red O and Masson staining were used to evaluate the plaque area and aortic root *** CD4^(+)CD25^(+)Foxp3^(+)Treg counts in the lymph nodes and spleen cells were detected using flow cytometric *** transforming growth factor-β1(TGF-β1),interleukin(IL)-10,and IL-6 serum levels were examined by MILLIPLEX?MAP *** real-time reverse transcription PCR(qRT-PCR)and Western blot were utilized to assess the expression of TGF-βmRNA and protein in the *** expression of CD4^(+)T lymphocytes,macrophages and smooth muscle cells in the aortic root were detected by immunofluorescence ***:HXF reduced plaque area in ApoE^(-/-)mice(Pounts in the lymph nodes and spleen cells(P0.05).Also,HXF upregulated the expression of TGF-βmRNA and protein in the aorta(P<0.05).Additionally,HXF attenuated CD4^(+)T lymphocytes,macrophages and smooth muscle cells in aortic root plaque(P<0.01).Furthermore,the depletion of Tregs with CD25

关键词： atherosclerosis Huxin Formula Tregs immune responses inflammation

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Lightweight Body-In-White Design Driven by Optimization Technology

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Automotive Innovation 2018年第3期1卷 255-262页

作者： Heguo ou xiaodong Tang Jieping xiao Yuanbo Wang Zhongmin Ma Off-Road Vehicle R&D Beijing Automotive Industry CorporationNo.99 Shuanghe StreetShunyi DistrictBeijingChina

Structural optimization technologies are increasingly applied to lightweight automotive structural *** a body-inwhite(BIW)development project,optimization technologies are applied in three steps that are seamlessly integrated into engineering *** following a design-driven approach,an innovative design that was 50.65 kg lighter than the base design was ***,topology optimization was used to investigate the optimal material distribution in a given design space,and helped in extracting the main load path,while considering crashworthiness,NVH,and static stiffness performance *** the second step,the effective design of a beam cross-section and feasible joints was carried out based on optimization technology and expert *** this step,the deep involvement of manufacturing process experts on stamping and joint connection feasibility analysis increased the chance of success *** sensitivity analysis,topography optimization,and gauge optimization of the created draft 3D BIW frame comprised the last step before finalizing the initial *** new design was validated by full load case simulations,including full vehicle crashworthiness analysis,mode frequency,and body mount point dynamic stiffness analysis,and BIW stiffness and component attachment stiffness *** validation results indicate that the new BIW design achieves the performance goal,while being 13.3%lighter than the base design.

关键词： BIW design Lightweight design Structural optimization Optimization technology

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Simultaneous ISAR imaging of group targets flying in formation

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Chinese Journal of Aeronautics 2014年第6期27卷 1554-1561页

作者： Chen Jie xiao Huaitie song Zhiyong Fan Hongqi Automatic Target Recognition Laboratory National University of Defense Technology

This paper proposes a novel inverse synthetic aperture radar（ISAR） imaging method based on second-order keystone transform（KT） and Sandglass transform for group targets flying in a formation with constant accelerated rectilinear motion in the same radar beam. First, range curvature and range walk of each sub-target among group targets are corrected by the second-order KT combined with the quadratic phase term compensation. After range alignment, the signals in each range frequency cell can be modelled as multiple chirp signals and then the Sandglass transform is utilized to cross-range imaging, which transforms the time–frequency distribution of the signals in each range frequency cell into beelines parallel to the slow time axis simultaneously. Finally, cross-range profiles of group targets in each range frequency cell are obtained via a projection of the perk of every scatterer in the two-dimensional accumulation plane onto the frequency axis. The advantage of the proposed method is that it can align range profiles of each sub-target simultaneously and image cross-range profiles directly without separating the returned signals, which simplifies the operation procedure. Simulation results are used to demonstrate the effectiveness of the proposed method.

关键词： Formation flying Group targets Inverse synthetic aperture radar Keystone transform Radar imaging Sandglass transform

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Numerical Investigation on Severe Slugging in A Catenary Riser

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China Ocean Engineering 2019年第5期33卷 628-635页

作者： QI xiao-liang GAO song GUO Hai-yan College of Engineering Ocean University of China Qingdao 266100 China Marine Design & Research Institute of China Shanghai 200240 China

A mathematical model is presented to study the main characteristics of severe slugging in a downward inclined pipeline followed by a catenary riser. In this model, both simplified transient model and phase distribution model are included so that the flow characteristics of each stage for severe slugging can be accurately reproduced, especially for blowout stage. The results show that the flow features of severe slugging can be simulated by the proposed mathematical model. A good agreement between the experimental data and the numerical results is observed. The model can predict the transient fluctuation of many respects, such as the superficial gas velocity at the bottom of the riser and the average velocity at the outlet of the riser.

关键词： severe slugging pipeline-riser system phase distribution transient fluctuation

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Change in Sediment Provenance Near the Current Estuary of Yellow River Since the Holocene Transgression

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Journal of Ocean University of China 2018年第3期17卷 535-544页

作者： song Sheng FENG Xiuli LI Guogang LIU xiao xiao xiao FENG Li Key Laboratory of Submarine Geosciences and Prospecting College of Marine Geosciences Ocean University of China Marine Engineering and Prospecting Institute of North China Sea North China Sea Branch of the State Oceanic Administration

Sedimentary sequence and sediment provenance are important factors when it comes to the studies on marine sedimentation. This paper studies grain size distribution, lithological characteristics, major and rare earth elemental compositions, micropaleontological features and ^(14)C ages in order to examine sedimentary sequence and sediment provenance of the core BH6 drilled at the mouth of the Yellow River in Bohai Sea. According to the grain size and the micropaleontological compositions, 4 sedimentary units have been identified. Unit 1(0–8.08 mbsf) is of the delta sedimentary facies, Unit 2(8.08–12.08 mbsf) is of the neritic shelf facies, Unit 3(12.08–23.85 mbsf) is of near-estuary beach-tidal facies, and Unit 4(23.85 mbsf–) is of the continental lake facies. The deposits from Unit 1 to Unit 3 have been found to be marine strata formed after the Holocene transgression at about 10 ka BP, while Unit 4 is continental lacustrine deposit formed before 10 ka BP. The provenances of core BH6 sediments show properties of the continental crust and vary in different sedimentary periods. For Unit 4 sediments, the source regions are dispersed while the main provenance is not clear, although the parent rock characteristics of a few samples are similar to the Luanhe River sediments. For Unit 3, sediments at 21.1–23.85 mbsf have been mainly transported from the Liaohe River, while sediments above 21.1 mbsf are mainly from the Yellow River and partially from the Liaohe River. For Unit 2, the sediments have been mainly transported from the Yellow River, with a small amount from other rivers. For Unit 1, the provenance is mainly the Yellow River catchment. These results help in better understanding the evolution of the Yellow River Delta.

关键词： Yellow River Estuary Holocene transgression rare earth element provenance

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Distribution and accumulation of biogenic silica in the intertidal sediments of the Yangtze Estuary

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Journal of Environmental Sciences 2008年第5期20卷 543-550页

作者： Hou Lijun LIU Min XU Shiyuana YAN Huimin ou Dongni CHENG Shubo LIN xiao State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China Key Laboratory of Geographical information Science of the Ministry of Education East China Normal University Shanghai 200062 China

Sedimentary biogenic silica is known to be an important parameter to understand biogeochemical processes and paleoenviromental records in estuarine and coastal ecosystems. Consequently, it is of great significance to investigate accumulation and distribution of biogenic silica in sediments. The two-step mild acid-mild alkaline extraction procedure was used to leach biogenic silica and its early diagenetic products in intertidal sediments of the Yangtze Estuary. The results showed that total biogenic silica （t-BSi） in the intertidal sediments varied from 237.7-419.4 μmol Si/g, while the mild acid leachable silica （Si-HCl） and the mild alkaline leachable silica （Si- Alk） were in the range of 25.1-72.9 μmol Si/g and 208.1-350.4 μmol Si/g, respectively. Significant correlations were observed for the grain size distributions of sediments and different biogenic silica pools in intertidal sediments. This confirms that grain size distribution can significantly affect biogenic silica contents in sediments. Close relationships of biogenic silica with organic carbon and nitrogen were also found, reflecting that there is a strong coupling between biogenic silica and organic matter biogeochemical cycles in the intertidal system of the Yangtze Estuary. Additionally, the early diagenetic changes of biogenic silica in sediments are discussed in the present study.

关键词： biogenic silica early diagenesis intertidal flats the Yangtze Estuary

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Experimental study on the mechanism of flow blockage formation in fast reactor

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Nuclear Science and Techniques 2023年第6期34卷 171-182页

作者： Wen-Hui Jin song-Bai Cheng xiao-Xing Liu Sino-French Institute of Nuclear Engineering and Technology Sun Yat-Sen UniversityZhuhai519082China

Various sources of solid particles might exist in the coolant flow of a liquid metal cooled fast reactor(e.g.,through chemical interaction between the coolant and impurities,air,or water,through corrosion of structural materials,or from damaged/molten fuel).Such particles may cause flow blockage accidents in a fuel assembly,resulting in a reduction in coolant flow,which potentially causes a local temperature rise in the fuel cladding,cladding failure,and fuel *** understand the blockage formation mechanism,in this study,a series of simulated experiments was conducted by releasing different solid particles from a release device into a reducer pipe using *** detailed analyses,the influence of various experimental parameters(e.g.,particle diameter,capacity,shape,and static friction coefficient,and the diameter and height of the particle release nozzle)on the blockage characteristics(i.e.,blockage probability and position)was *** the current range of experimental conditions,the blockage was significantly influenced by the aforementioned *** ratio between the particle diameter and outlet size of the reducer pipe might be one of the determining factors governing the occurrence of ***,increasing the ratio enhanced blockage(i.e.,larger probability and higher position within the reducer pipe).Increasing the particle size,particle capacity,particle static friction coefficient,and particle release nozzle diameter led to a rise in the blockage probability;however,increasing the particle release nozzle height had a downward influence on the blockage ***,blockage was more likely to occur in non-spherical particles case than that of spherical *** study provides a large experimental database to promote an understanding of the flow blockage mechanism and improve the validation process of fast reactor safety analysis codes.

关键词： Liquid metal cooled fast reactor Flow blockage Granular jamming Experimental study

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