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An Algorithm to Analyze Electron Backscatter Diffraction Data for Grain Reconstruction:from Methodology to Application

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Acta Metallurgica Sinica(English Letters) 2016年第5期29卷 491-499页

作者： xue-Hao zheng Hong-Wang Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences National Engineering Research Center for Equipment and Technology of Cold Strip Rolling College of Mechanical Engineering Yanshan University

An algorithm for grain reconstruction based on electron backscatter diffraction data was proposed in this paper. This algorithm can well record the original data arrangement when an external file for the reconstructed grain（s） was exported for further post-processing. Assisted by an in-house MATLAB program, grain reconstruction, lattice rotations, orientation spreads, and slip system analysis can be performed. The validity of this algorithm has been successfully tested by polycrystalline Ni before and after channel die compression.

关键词： Grain reconstruction Algorithm Electron backscatter diffraction Deformation Nickle

Stem cell therapy: A promising treatment for COVID-19

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World Journal of Clinical Cases 2021年第36期9卷 11148-11155页

作者： Zhi-xue zheng Department of General Surgery Beijing Jishuitan HospitalBeijing 100035China

Novel coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has become a global ***-2 is an RNA virus and has a glycosylated spike(S)protein used for genome ***-19 can lead to a cytokine storm and patients usually have early respiratory signs and further secondary infections,which can be ***-19 has entered an emergency phase,but there are still no specific effective drugs for this *** stem cells(MSCs)are multipotent stromal cells,which cause antiapoptosis and can repair damaged epithelial *** clinical trials have proved that MSC therapy could be a potential feasible therapy for COVID-19 patients,especially those with acute respiratory distress syndrome,without serious adverse events or ***,more studies are needed in the future,in order to confirm the effect of this therapy.

关键词： COVID-19 SARS-CoV-2 Mesenchymal stem cells Pandemic Stem cell therapy

Heavy Cycles in 2-connected Triangle-free Weighted Graphs

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Acta Mathematica Sinica,English Series 2015年第10期31卷 1555-1562页

作者： xue zheng LV Pei WANG Department of Mathematics Renmin University of China Department of Mathematics and Physics China University of Petroleum

A weighted graph is one in which every edge e is assigned a nonnegative number, called the weight of e. The sum of the weights of the edges incident with a vertex v is called the weighted degree of v, denoted by dw（v）. The weight of a cycle is defined as the sum of the weights of its edges. Fujisawa proved that if G is a 2-connected triangle-free weighted graph such that the minimum weighted degree of G is at least d, then G contains a cycle of weight at least 2d. In this paper, we proved that if G is a 2-connected triangle-free weighted graph of even size such that dw（u）＋ dw（v） ≥ 2d holds for any pair of nonadjacent vertices u, v ∈ V（G）, then G contains a cycle of weight at least 2d.

关键词： Heavy cycles triangle-free graphs weighted graphs

Total [1,2]-domination in Graphs

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Acta Mathematicae Applicatae Sinica 2018年第4期34卷 801-812页

作者： xue-zheng LV Baoyindureng WU Department of Mathematics Renmin University of China Beijing 100872 China College of Mathematics and System Sciences Xinjiang University Urumqi 830046 China

A subset S V in a graph G =（V, E） is a total [1, 2]-set if, for every vertex v ∈ V, 1 ≤ ｜N（v）∩S｜ ≤2. The minimum cardinality of a total [1, 2]-set of G is called the total [1, 2]-domination number, denoted byγt[1,2]（G）.We establish two sharp upper bounds on the total [1,2]-domination number of a graph G in terms of its order and minimum degree, and characterize the corresponding extremal graphs achieving these bounds. Moreover,we give some sufficient conditions for a graph without total [1, 2]-set and for a graph with the same total[1, 2]-domination number, [1, 2]-domination number and domination number.

关键词： total [1 2]-set total [1 2]-domination number [1 2]-set

Influence of Mass-Loss on the Orbit of Comet Shoemaker-Levy 9

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Chinese Physics Letters 1996年第6期13卷 477-480页

作者： YU Li-zhong zheng xue-tang Department of Applied Physics Nanjing University of Science and TechnologyNanjing 210094

Using the Jeans problem and the Fermi problem of two bodies with variable masses,the influence of solar and cometary mass-loss on the orbit of comet Shoemaker-Levy 9(SL9)is discussed in this *** is shown that solar and cometary mass-loss both will cause the secular and periodic terms in the semimajor axis a of comet *** influence of solar mass-loss on the orbit of comet SL9 is very small and it may be *** the influence of mass-loss of comet SL9 itself on its orbit is large and it may cause the secular variation in a to be about l04 km every *** cometary mass-loss will obviously influence the time and place of the comet SL9 crashing into Jupiter.

关键词： comet Jupiter mass

Crystal Structure of a Novel Complex Na_4[Y(PDC)_2(BTC)]·5H_2O with One-Dimensional Helical Network Structure (H2PDC = 2,6-Pyridinedicarboxylic acid)( H_3BTC = 1,3,5-Benzenetricarboxylic acid )

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Chinese Journal of Structural Chemistry 2005年第10期24卷 1181-1185页

作者： xue Xu-Fei CHE Yun-Xia xue Lin zheng Ji-Min Department of Chemistry Nankai University Tianjin 300071 China

A novel title complex, C23H19N2O19Na4Y （Mr= 808.27）, has been synthesized by hydrothermal reaction and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a = 13.560（3）, b = 14.016（3）, c = 14.948（4） A, β = 99.492（4）°, Z = 4, V = 2802.2（12） A^3, Dc = 1.916 g/cm^3,μ（MoKα） = 2.241 mm^-1, F（000） = 1624, the final R = 0.0337 and wR = 0.0828 for 4044 observed reflections（I〉 2σ（I））. In the crystal, each eight- coordinated Y（Ⅲ） atom is linked by carboxyl groups of BTC to form a one-dimensional helical network structure.

关键词： 1,3,5-benzenetricarboxylic acid 2,6-pyridinedicarboxylic acid,hydrothermal synthesis crystal structure

Influence of blasting on the properties of weak intercalation of a layered rock slope

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International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 7-11页

作者： Xiao-lin Song Ji-chun Zhang xue-bin Guo zheng-xue Xiao School of Civil Engineering Southwest Jiaotong University Chengdu 610031 China Traction Power State Key Laboratory Southwest Jiaotong University Chengdu 610031 China School of Environmental Engineering Southwest University of Science and Technology Mianyang 621002 China

A precondition for correctly analyzing the stability of a slope and designing its bracing structure is to study and determine the influence of excavation blasting on the properties of weak intercalation in the layered rock slope. On the basis of in-situ stratification-cracking blasting tests, the properties of weak intercalation were investigated using the LS-DYNA3D program. The displacement distribution and compactness of weak intercalation at different positions away from the charge center and their various laws are discussed. The critical displacement of stratification-cracking （0.1 mm） was obtained, and an approximate expression of compactness were deduced. Furthermore, through the simulation of a layered rock blasting under the same geological conditions, the stratification-cracking effect of deep-hole blasting on the properties of weak intercalation was compared with that of short-hole blasting, and the influencing differences, in addition to their causes, were analyzed. The results indicated that the blasting cavity of weak intercalation in short-hole blasting with a radius of 40 mm was nearly a circle, whose radius was about 28.7 cm; whereas in deep-hole blasting with a radius of 150 mm, the shape of the blasting cavity was different from that in short-hole blasting, the radius of the cavity behind the charge （89.1 cm） was further smaller than those of the other three （138.7 cm）, and there were sharp crinkles on the surface of weak intercalation. When the distance from the charge center （DCC） was less than 40 and 150 cm in short-hole and deep-hole blasting, respectively, the displacement of weak intercalation was reduced remarkably with the increase in DCC.

关键词： rock slope bench blasting numerical simulation intercalation

Sensitivity analysis for a type of statically stable sailcrafts

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Acta Mechanica Sinica 2012年第2期28卷 532-542页

作者： zheng-xue Li Jun-Feng Li He-Xi Baoyin School of Aerospace Tsinghua University100084 BeijingChina

Two types of sensitivities are proposed for stat- ically stable sailcrafts. One type is the sensitivities of solar-radiation-pressure force with respect to position of the center of mass, and the other type is the sensitivities of solar-radiation-pressure force with respect to attitude. The two types of sensitivities represent how the solar-radiation- pressure force changes with the position of mass center and the attitude. Sailcrafts with larger sensitivities undergo larger error of the solar-radiation-pressure force, leading to larger orbit error, as demonstrated by simulation. Then as a case study, detailed formulas are derived to calculate the sensi- tivities for sailcrafts with four triangular sails. According to these formulas, in order to reduce both types of sensitivities, the angle between opposed sails should not be too large, and the center of mass should be as close to the axis of symmetry of the four sails as possible and as far away from the center of pressure of the sailcraft as possible.

关键词： Statically stable sailcraft Sensitivity Solar- radiation-pressure force error. Mass center and pressure cen- ter errors Attitude and orbit errors

Microstructure and performance of WC-Co-Cr coating with ultrafine/nanocrystalline structures

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Rare Metals 2018年第11期37卷 968-975页

作者： xue-zheng Wang Hai-Bin Wang xue-Mei Liu Chao Hou Xiao-Yan Song College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials Education Ministry of ChinaBeijing University of Technology

The WC-lOCo-4Cr composite powder was synthesized firstly. Then the composite powder was agglomerated to prepare thermal spraying feedstock. The ultrafine/nanostructured WC-lOCo-4Cr coating was prepared by high velocity oxygen fuel thermal spraying. The phase constitution, elemental distribution and microstructure of the coating were characterized by X-ray diffraction and transmission electron microscopy, respectively. The wear resistance and corrosion resistance of the prepared composite coating were tested. The results show that the main phases of the coating include WC, binding phase with partial amorphous structure, with a little WC and Co(Cr)coexisting. The distributions of Co and Cr elements from the phase boundary to the eutectic area then to Co zone were analyzed quantitatively. The mechanisms for the formation of the microstructure and effects of Cr on the performance of the composite coating are proposed.

关键词： In situ synthesis High velocity oxygen fuel Ultrafine/nanostructure Composite coating Phase constitution