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An active M star with X-ray double flares disguised as an ultra-luminous X-ray source

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Research in Astronomy and Astrophysics 2016年第2期16卷 119-126页

作者： jin-cheng guo Ji-Feng Liu Song Wang Yue Wu Yu-Xiang Qin Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China University of Chinese Academy of Sciences Beijing 100049China School of Physics The University of MelbourneParkvilleVictoria 3010Australia

Here we present research on an ultra-luminous X-ray source （ULX） candidate 2XMM J 140229.91＋542118.8. The X-ray light curves of this ULX candidate in M 101 exhibit features of a flare star. More importantly, the Chandra light curve displays unusual X-ray double flares, which is comprised of two close peaks. The X-ray （0.3-11.0 keV） flux of the first peak was derived from the two-temperature APEC model as ～ 1.1 ±0.1× 10-12 ergcm-2 s-1. The observed flux at its first peak increased by about two orders of magnitude in X-ray as compared to quiescence. The slope of the second fast decay phase is steeper than the slope of the first fast decay phase, indicating that the appearance of a second flare accelerated the cooling of the first flare in a way we do not understand yet. We also observed its optical counterpart using a 2.16 m telescope administered by National Astronomical Observatories, Chinese Academy of Sciences. By optical spectral fitting, it is confirmed to be a late type dMe2.5 star. According to the spectral type and apparent magnitude of its optical counterpart, we estimate the photometric distance to be ～ 133.4 ±14.2 pc. According to the X-ray spectral fitting, a possible explanation is provided. However, more similar close double flares are needed to confirm whether this accelerated cooling event is a unique coincidence or a common physical process during double flaring.

关键词： stars flare -- X-ray stars -- galaxies individual (M101)

Comparative Experimental Study on Heat Transfer Characteristics of Building Exterior Surface at High and Low Altitudes

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Journal of Thermal Science 2024年第3期33卷 1119-1131页

作者： JIA Yonghong guo Shurui LI jin guo Lei cheng Zhu ZHANG Yin YANG Hanyu LONG Enshen Institute for Disaster Management and Reconstruction Sichuan UniversityChengdu610065China MOE Key Laboratory of Deep Earth Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu610065China

The external surface heat transfer coefficient of building envelope is one of the important parameters necessary for building energy saving design,but the basic data in high-altitude area are ***,the authors propose a modified measurement method based on the heat balance of a model building,and use the same model building to measure its external surface heat transfer coefficient under outdoor conditions in chengdu city,China at an altitude of 520 m and Daocheng city at an altitude of 3750 m *** results show that the total heat transfer coefficient(h_(t))of building surface in high-altitude area is reduced by 34.48%.The influence of outdoor wind speed on the convective heat transfer coefficient(h_(c))in high-altitude area is not as significant as that in low-altitude *** fitting relation between convection heat transfer coefficient and outdoor wind speed is also *** the same heating power,the average temperature rise of indoor and outdoor air at highaltitude is 41.9%higher than that at low altitude,and the average temperature rise of inner wall is 25.8%higher than that at low *** shows that high-altitude area can create a more comfortable indoor thermal environment than low-altitude area under the same energy consumption *** is not appropriate to use the heat transfer characteristics of the exterior surface of buildings in low-altitude area for building energy saving design and related heating equipment selection and system terminal matching design in high-altitude area.

关键词： altitude heat transfer characteristics convective heat transfer coefficient(h_(c)) radiative heat transfer coefficient(h_(r)) external building envelope

Multi-Objective Multi-Variable Large-Size Fan Aerodynamic Optimization by Using Multi-Model Ensemble Optimization Algorithm

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Journal of Thermal Science 2024年第3期33卷 914-930页

作者： XIONG jin guo Penghua LI jingyin School of Energy and Power Engineering Xi’an Jiaotong UniversityXi’an710049China

The constrained multi-objective multi-variable optimization of fans usually needs a great deal of computational fluid dynamics(CFD)calculations and is *** this study,a new multi-model ensemble optimization algorithm is proposed to tackle such an expensive optimization *** multi-variable and multi-objective optimization are conducted with a new flexible multi-objective infill *** addition,the search direction is determined by the multi-model ensemble assisted evolutionary algorithm and the feature extraction by the principal component analysis is used to reduce the dimension of optimization ***,the proposed algorithm and other two optimization algorithms which prevail in fan optimizations were compared by using test *** the same number of objective function evaluations,the proposed algorithm shows a fast convergency rate on finding the optimal objective function ***,this algorithm was used to optimize the rotor and stator blades of a large axial fan,with the efficiencies as the objectives at three flow rates,the high,the design and the low flow ***-two variables were included in the optimization *** results show that compared with the prototype fan,the total pressure efficiencies of the optimized fan at the high,the design and the low flow rate were increased by 3.35%,3.07%and 2.89%,respectively,after CFD simulations for 500 fan candidates with the constraint for the design *** optimization results validate the effectiveness and feasibility of the proposed algorithm.

关键词： multi-objective optimization surrogate-assisted evolutionary algorithm axial fan computational fluid dynamics aerodynamic optimization

Configuration Synthesis and Grasping Performance Analysis of Multi-Loop Coupling Capture Mechanism for Launch and Recovery of Torpedo-Shaped Autonomous Underwater Vehicle

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China Ocean Engineering 2024年第3期38卷 453-466页

作者： ZHANG guo-xing XIA Xin-lu guo jin-wei School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological ***,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain ***,the screw theory is employed to analyze the degree of freedom(DoF)of the capture ***,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried *** with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried ***,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are ***,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is *** work provides technical reserves for the research and development of AUV capture special equipment.

关键词： capture mechanism torpedo-shaped AUVs configuration synthesis launch and recovery grasping performance analysis

In situ anchoring in carbon matrix of Bi_(2)O_(2)CO_(3) as a high-performance anode material for Li-ion batteries

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Rare Metals 2024年第8期43卷 3634-3646页

作者： Pu-Qiang He Jun guo Hui Huang Zhong-cheng guo Faculty of Metallurgy and Energy Engineering Kunming University of Science and TechnologyKunming 650093China Research Center of Metallurgical Electrode Materials Engineering Technology Kunming 650106China Kunming Hendera Science and Technology Co. Ltd.Kunming 650106China

Bismuth-based anode materials have been regarded as promising Li-ion batteries due to their high theoretical ***,their low conductivity and associated volume expansion inhabited their *** this work,Bi_(2)O_(2)CO_(3)@C composites were successfully synthesized by in situ anchoring of flower-like Bi_(2)O_(2)CO_(3) nanosheets on a carbon-based substrate via *** unique composited structure of Bi_2O_(2)-CO_(3)@C leads to a stable specific capacity of 547 mAh·g^(-1)after 100 cycles at a current density of 0.1 A·g^(-1).Notably,it demonstrates excellent rate capability with a specific capacity of 210 mAh·g^(-1)at 5 A·g^(-1).After 550 cycles at a current density of 0.5 A·g^(-1),a high reversible capacity of nearly 400 mAh·g^(-1)was ***,in situ X-ray diffraction measurements clearly demonstrate the conversion between Bi and Li_(3)Bi during alloying/dealloying,confirming the good electrochemical reversibility of the materials for Li *** reaction kinetics of Bi_(2)O_(2)CO_(3)@C were further investigated using galvanostatic intermittent titration ***,Bi_2O_(2)-CO_(3)@C exhibited excellent long-term stability,maintaining its high reversible capacity for over 200 cycles at a current density of 0.5 A·g^(-1)in a full cell configuration using Li_(1.20)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2) as the cathode *** result further underscores its promising potential for lithium-ion *** work may provide inspiration for the design of alloy-type negative electrode materials for high-performance rechargeable batteries.

关键词： Bi_(2)O_(2)CO_(3) Composite materials Anode materials Full batteries

MD Simulation of Diffusion Behaviors in Collision Welding Processes of Al-Cu, Al-Al, Cu-Cu

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Computers, Materials & Continua 2024年第6期79卷 3455-3468页

作者： Dingyi jin guo Wei School of Intelligent Manufacturing Hunan First Normal UniversityChangsha410082China School of Physics and Technology Center for Ion Beam ApplicationHubei Nuclear Solid Physics Key LaboratoryWuhan UniversityWuhan430072China

To investigate the effects of material combinations and velocity conditions on atomic diffusion behavior near collision interfaces,this study simulates the atomic diffusion behavior near collision interfaces in Cu-Al,Al-Al and Cu-Cu combinations fabricated through collision welding using molecular dynamic(MD)*** atomic diffusion behaviors are compared between similar metal combinations(Al-Al,Cu-Cu)and dissimilar metal combinations(Al-Cu).By combining the simulation results and classical diffusion theory,the diffusion coefficients for similar and dissimilar metal material combinations under different velocity conditions are *** effects of material combinations and collision velocity on diffusion behaviors are also *** diffusion behaviors of dissimilar material combinations strongly depend on the transverse velocity,whereas those of the similar material combinations are more dependent on the longitudinal *** findings can provide guidance for optimizing welding parameters.

关键词： Atomic diffusion behavior molecular dynamics collision welding

Evaluation of metoprolol standard dosing pathway in Chinese patients with acute coronary syndrome:a prospective multicenter single-arm interventional study

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Journal of Geriatric Cardiology 2023年第4期20卷 256-267页

作者： Xiao-Yun YIN Yun-Mei ZHANG Ai-Dong SHEN jing-Ping WANG Zhe-Xun LIAN Yi-Bing SHAO Wen-Qi ZHANG Shu-Ying ZHANG Yang ZHENG Kang cheng Biao XU cheng-Xing SHEN Rong-Chong HUANG jin-cheng guo guo-Sheng FU Dong-Kai SHAN Dan-Dan LI Yun-Dai CHEN Senior Department of Cardiology the Sixth Medical CentreChinese PLA General HospitalBeijingChina Medical School of Chinese PLA BeijingChina Department of Cardiology Yunnan First People’s HospitalKunmingChina Department of Heart Center Beijing Friendship HospitalCapital Medical UniversityBeijingChina Department of Cardiology Shanxi Cardiovascular HospitalTaiyuanChina Department of Cardiology the Affiliated Hospital of Qingdao UniversityQingdaoChina Department of Cardiology Qingdao Municipal HospitalQingdaoChina Department of Cardiology China-Japan Union Hospital of Jilin UniversityChangchunChina Department of Cardiology the Affiliated Zhongshan Hospital of Dalian UniversityZhongshanChina Cardiovascular Center the First Hospital of Jilin UniversityChangchunChina Department of Cardiology the Affiliated Hospital of Northwest University&Xi’an No.3 HospitalXi’anChina Department of Cardiology Nanjing Drum Tower HospitalNanjing University Medical SchoolNanjingChina Department of Cardiology Shanghai Jiao Tong University Affiliated Sixth People’s HospitalShanghaiChina Department of Cardiology Beijing Friendship HospitalCapital Medical UniversityBeijingChina Department of Cardiology Beijing Luhe HospitalCapital Medical UniversityBeijingChina Department of Cardiology School of MedicineSir Run Run Shaw HospitalZhejiang UniversityHangzhouChina

OBJECTIVE To evaluate the feasibility and tolerability of metoprolol standard dosing pathway(MSDP)in Chinese patients with acute coronary syndrome(ACS).METHODS In this multicenter,prospective,open label,single-arm and interventional study that was conducted from February 2018 to April 2019 in fifteen Chinese hospitals.A total of 998 hospitalized patients aged≥18 years and diagnosed with ACS were *** MSDP was applied to all eligible ACS patients based on the standard treatment recommended by international *** primary endpoint was the percentage of patients achieving the target dose at discharge(V2).The secondary endpoints included the heart rate and blood pressure at V2 and four weeks after discharge(V4),and percentage of patients experiencing bradycardia(heart rate<50 beats/min),hypotension(blood pressure<90/60 mmHg)and transient cardiac dysfunction at V2 and *** Of the 998 patients,29.46%of patients achieved the target dose(≥95 mg/d)at *** total population was divided into two groups:target group(patients achieving the target dose at V2)and non-target group(patients not achieving the target dose at V2).There was significant difference in the reduction of heart rate from baseline to discharge in the two groups(-4.97±11.90beats/min vs.-2.70±9.47 beats/min,P=0.034).There was no significant difference in the proportion of bradycardia that occurred in the two groups at V2(0 vs.0,P=1.000)and V4(0.81%vs.0.33%,P=0.715).There was no significant difference in the proportion of hypotension between the two groups at V2(0.004%vs.0.004%,P=1.000)and V4(0 vs.0.005%,P=0.560).No transient cardiac dysfunction occurred in two groups during the study.A total of five adverse events(1.70%)and one serious adverse event(0.34%)were related to the pathway in target *** In Chinese ACS patients,the feasibility and tolerability of the MSDP have been proved to be acceptable.

关键词： patients prospective coronary

Development characteristics and controlling factors of fractures in lacustrine shale and their geological significance for evaluating shale oil sweet spots in the third member of the Shahejie Formation in the Qikou Sag, Bohai Bay Basin

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Petroleum Science 2024年第2期21卷 791-805页

作者： Xu Zeng Tao Yang Jian-Wei Feng Cong-Sheng Bian Ming Guan Wei Liu Bing-cheng guo jin Dong Research Institute of Petroleum Exploration and Development China National Petroleum CorporationBeijing100083China College of Geosciences China University of Petroleum(Beijing)Beijing102249China Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China School of Earth Sciences China University of PetroleumQingdao266400ShandongChina

Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fractures, remain controversial. In this study, we integrate thin section analysis and microcomputed tomography(CT) data from several lacustrine shale samples from the third member(Es3) of the Shahejie Formation, Qikou Sag, Bohai Bay Basin, to assess the fractures in detail. The goal is to reveal the development characteristics, controlling factors, and geological significance for evaluating sweet spots in a shale oil play. The fractures in the Es3contain high-angle structural and horizontal bed-parallel fractures that are mostly shear and extensional. Various factors influence fracture development,including lithofacies, mineral composition, organic matter content, and the number of laminae. Structural fractures occur predominantly in siltstone, whereas bed-parallel fractures are abundant in laminated shale and layered mudstone. A higher quartz content results in higher shale brittleness, causing fractures, whereas the transformation between clay minerals contributes to the development of bedparallel fractures. Excess pore pressure due to hydrocarbon generation and expulsion during thermal advance can cause the formation of bed-parallel fractures. The density of the bed-parallel and structural fractures increases with the lamina density, and the bed-parallel fractures are more sensitive to the number of laminae. The fractures are critical storage spaces and flow conduits and are indicative of sweet spots. The laminated shale in the Es3with a high organic matter content contains natural fractures and is an organic-rich, liquid-rich, self-sourced shale play. Conversely, the siltstone, massive mudstone, and argillaceous carbonate lithofacies contain lower amounts of organic matter and do not have bed-parallel fractures. However, good reservoirs can form in th

关键词： Fractures Development characteristics Controlling factors Shale oil Sweet spot

Application of a New Measuring Method to Large Size Measurement in an Automobile Panel

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International Journal of Plant Engineering and Management 2009年第2期14卷 78-83页

作者： ZHANG De-hai LIANG jin guo cheng School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049 China

In view of the automobile panel＇s features of complex shapes, the higher requirements of appearance surface quality, and the more accurate mechanical model for CAE simulation etc, a kind of measurement method for large size measurement was presented. The method was composed of digital close-range industrial photogrammetry technology and computer binocular vision technology, it could measure workpieces quickly and precisely. First, XJ- TUDP software, which was a kind of photogrammetry software, figured out un-coded points and coded-points which fixed on the surface of a large part and took a solid base for the fusion of many pieces point clouds. Second, based on XJTUOM, which was a kind of 3D dense point cloud optical measure software, imported global landmarks points came from XJTUDP into XJTUOM, and point clouds can be assembled automatically. 3D data of the object surface may be acquired precisely by means of this method. Finally, an automobile door was taken for example and the experimental data was combined so we can see that the developed system possesses better accuracy and it can ad- dress the feature of a large workpiece.

关键词： photogrammetry automobile panel XJTUDP software XJTUOM software