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The k-point Exponent Set of Primitive Digraphs with Girth 2

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Acta Mathematicae Applicatae Sinica 2008年第4期24卷 573-582页

作者： She-xi Chen Wei-jun liu jin-wang liu School of Mathematics and Computational Science Hunan University of Science and Technology Xiangtan411201 China School of Mathematics Sciences and Computing Technology Central South University Changsha 410075 China

Let D = （V, E） be a primitive digraph. The vertex exponent of D at a vertex v∈ V, denoted by expD（v）, is the least integer p such that there is a v →u walk of length p for each u ∈ V. Following Brualdi and liu, we order the vertices of D so that exPD（V1） ≤ exPD（V2） …≤ exPD（Vn）. Then exPD（Vk） is called the k- point exponent of D and is denoted by exPD （k）, 1≤ k ≤ n. In this paper we define e（n, k）：= max{expD （k）｜ D ∈ PD（n, 2）} and E（n, k）：= {exPD（k）｜ D ∈ PD（n, 2）}, where PD（n, 2） is the set of all primitive digraphs of order n with girth 2. We completely determine e（n, k） and E（n, k） for all n, k with n ≥ 3 and 1 ≤ k ≤ n.

关键词： Primitive digraph k-point exponent exponent set

Least-Squares Solution of Inverse Problem for Hermitian Anti-reflexive Matrices and Its Appoximation

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Acta Mathematica Sinica,English Series 2006年第2期22卷 477-484页

作者： Zhen Yun PENG Yuan Bei DENG jin wang liu Department of Mathematics Hunan University of Science and Technology Department of Mathematics Central South University Institute of Computational Mathematics Chinese Academy of Sciences

In this paper, we first consider the least-squares solution of the matrix inverse problem as follows： Find a hermitian anti-reflexive matrix corresponding to a given generalized reflection matrix J such that for given matrices X, B we have minA ｜｜AX - B｜｜. The existence theorems are obtained, and a general representation of such a matrix is presented. We denote the set of such matrices by SE. Then the matrix nearness problem for the matrix inverse problem is discussed. That is： Given an arbitrary A^＊, find a matrix A E SE which is nearest to A^＊ in Frobenius norm. We show that the nearest matrix is unique and provide an expression for this nearest matrix.

关键词： hermitian reflexive matrix hermitian anti-reflexive matrix matrix norm nearest matrix

Effects of tree size and organ age on variations in carbon,nitrogen,and phosphorus stoichiometry in Pinus koraiensis

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Journal of Forestry Research 2024年第3期35卷 155-165页

作者： Yanjun wang Guangze jin Zhili liu Center for Ecological Research Northeast Forestry UniversityHarbin 150040People's Republic of China Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education Northeast Forestry UniversityHarbin 150040People's Republic of China Northeast Asia Biodiversity Research Center Northeast Forestry UniversityHarbin 150040People's Republic of China

Carbon(C),nitrogen(N),and phosphorus(P)are of fundamental importance for growth and nutrient dynamics within plant organs and deserve more attention at regional to global ***,our knowledge of how these nutrients vary with tree size,organ age,or root order at the individual level remains *** determined C,N,and P contents and their stoichiometric ratios(i.e.,nutrient traits)in needles,branches,and fine roots at different organ ages(0-3-year-old needles and branches)and root orders(1st-4th order roots)from 64 Pinus koraiensis of varying size(Diameter at breast height ranged from 0.3 to 100 cm)in northeast *** factors were also *** results show that nutrient traits were regulated by tree size,organ age,or root order rather than soil *** a whole-plant level,nutrient traits decreased in needles and fine roots but increased in branches with tree *** the organ level,age or root order had a negative effect on C,N,and P and a positive effect on stoichiometric *** results demonstrate that nutrient variations are closely related to organ-specific functions and ecophysiological processes at an individual *** is suggested that the nutrient acquisition strategy by younger trees and organ fractions with higher nutrient content is for ***,nutrient storage strategy in older trees and organ fractions are mainly for steady *** results clarified the nutrient utilization strategies during tree and organ ontogeny and suggest that tree size and organ age or root order should be simultaneously considered to understand the complexities of nutrient variations.

关键词： Tree size Organ age(or root order) Carbon(C) Nitrogen(N) Phosphorus(P) Pinus koraiensis

Pb induced dislocation defects of PtCo systems: Strain-triggered oxygen reduction reaction for PEMFC

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Nano Research 2024年第4期17卷 2462-2472页

作者： Chun jin Qiheng wang jingjun liu Beijing Key Laboratory of Electrochemical Process and Technology for Materials Beijing 100029China Beijing University of Chemical Technology Beijing 100029China

Design and development of advanced electrocatalysts with high performance and low Pt consumption are crucial for reducing the kinetic energy barrier of the cathode oxygen reduction reaction(ORR)and improving the efficiency of proton exchange membrane fuel cells(PEMFC).In this study,we demonstrate a Pb-modulated PtCo system for efficient ORR,in which the inclusion of Pb in ternary alloys induces dislocation defects due to the significant difference in atomic ***-PtCoPb was confirmed to exhibit significantly higher ORR activity and stability in acidic *** practical PEMFC applications,it outperforms the corresponding commercial Pt/C with a mass activity of 0.58 A·mgPt^(-1),making it a promising alternative to state-of-the-art Pt-based *** combination of experimental results and density functional theory(DFT)calculations offers valuable atomic-level insights into the dislocation *** with a larger atomic radius is located in the lattice stretching region below the dislocation slip plane,forming a structure similar to a Cottrell atmosphere,which reduces the dislocation energy and puts the system in a lower energy *** Cottrell atmosphere pins the dislocation structure and stabilizes the ternary *** adjusting the amount of added Pb,a moderate level of dislocation density induces a tuned strain effect,thereby enhancing the electrocatalytic mechanism by optimizing the electronic structure of the alloy surface and the adsorption and desorption of oxygen *** work provides valuable insights into the design and development of lattice dislocation defect structures to trigger strain effects for improving ORR performance.

关键词： dislocation defect strain effect Pb-modulated oxygen reduction reaction

Nano-Twinning and Martensitic Transformation Behaviors in 316L Austenitic Stainless Steel During Large Tensile Deformation

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Acta Metallurgica Sinica(English Letters) 2023年第5期36卷 758-770页

作者： jin-wang liu Xian Luo Bin Huang Yan-Qing Yang Wen-Jie Lu Xiao-Wei Yi Hong wang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China

The evolutions of nano-twins and martensitic transformation in 316L austenitic stainless steel during large tensile deformation were studied by electron backscatter diffraction(EBSD)technology and transmission electron microscopy(TEM)in *** results show that due to the low stacking fault energy of the steel,phase transformation induced plasticity(TRIP)and twinning induced plasticity(TWIP)coexist during the tensile *** deformation firstly induces the formation of deformation twins,and dislocation pile-up is caused by the reduction of the dislocation mean free path(MFP)or grain refinement due to the twin boundaries,which further induces the martensitic *** the increase of tensile deformation,a large number of nano-twins andα’-martensite appear,and the width of nano-twins decreases gradually,meanwhile the frequency of the intersecting deformation twins *** martensitic transformation can be divided into two types:γ-austenite→α’-martensite andγ-austenite→ε-martensite.α’-martensite is mainly distributed near the twin boundaries,especially at the intersection of twins,whileε-martensite and stacking faults exist in the form of transition products between the twins and the matrix.

关键词： Austenitic stainless steel Intersecting-deformation twins Martensitic transformation High resolution transmission electron microscopy(HRTEM) Deformation mechanism

Synthesis of New Soluble Polyarylates Containing Phthalazinone Moiety

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Chinese Chemical Letters 2006年第1期17卷 140-142页

作者： Yu Rong GAO jin Yan wang Cheng liu Xi Gao JIAN Department of Polymer Science and Materials Dalian University of Technology Dalian 116012

A novel diacid chloride, 2-（4-chlorocarboxyphenyl）-4-[3,5-dimethyl-4-（4-chlorocarbo-xylphenoxy）phenyl]-2,3-phthalazin-l-one 2, was synthesized and used for the preparation of polyarylates with inherent viscosities of 0.25-0.37 dL·g^-1. The glass transition temperatures of polyarylates were in the range of 217-272℃. The temperatures at 10% weight loss of polyarylates were found to be in the range of 434-464℃ in nitrogen atmosphere and their structure was confirmed by FTIR and IH NMR. The amorphous polyarylates exhibited excellent solubility in a variety of solvents such as NMP, DMAc, DMF and chloroform.

关键词： Polyarylates phthalazinone solubility thermal behavior.

Generalized KKM-Type Theorems for Weakly Generalized KKM Mapping with Some Applications

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Acta Mathematicae Applicatae Sinica 2010年第2期26卷 311-320页

作者： Gu-sheng Tang Li-zhi Zhu jin-wang liu Cao-zong Cheng Department of Mathematics Hunan University of Science and Technology Xiangtan 411201 China Department of Mathematics Beijing University of Technology Beijing 100022 China

In this paper, we establish some new generalized KKM-type theorems based on weakly generalized KKM mapping without any convexity structure in topological spaces. As applications, some minimax inequalities and an existence theorem of equilibrium points for an abstract generalized vector equilibrium problem are proved in topological spaces. The results presented in this paper unify and generalize some known results in recent literature.

关键词： Weakly generalized KKM mapping Generalized KKM-type theorem Weakly generalized diagonally quasi-convex (W S K) mapping pair Generalized vector equilibrium

Evaluation of neointimal coverage in patients with coronary artery aneurysm formation after drug-eluting stent implantation by optical coherence tomography

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Chinese Medical Journal 2013年第11期126卷 2092-2097页

作者： TIAN Feng CHEN Yun-dai CHEN Lian SUN Zhi-jun GUO Jun jin Qin-hua liu Chang-N wang jin-da liu Hong-bin Department of Cardiology Chinese People's Liberation ArmyGeneral Hospital Beijing 100853 China

Background The vessel healing in patients with coronary artery aneurysms （CAA） that form after drug-eluting stent （DES） implantation is not clear. This study aims to assess the vessel healing in patients with CAA formation after DES implanation. Methods From June 2008 to August 2011, follow-up coronary angiography was conducted on 1160 patients who underwent percutaneous coronary intervention （PCI）. The average period of follow-up was about （18.95±13.05） months. A total of 175 patients who underwent DES implantation into de novo lesions and who underwent coronary angiography and optical coherence tomography （OCT） examination during follow-up were identified. Patients were divided into the CAA group （n=31） and non-CAA group （n=144） based on the results of the coronary angiography. The cardiac events including angina and acute myocardial infarction were noted; in addition, the neointimal thickness and the frequency of strut malapposition and strut uncoverage were also noted. Results A greater proportion of incomplete neointimal coverage （17.17% vs. 1.90%, P 〈0.001） and strut malapposition （18.20% vs. 1.38%, P 〈0.001） were observed in the CAA group. The neointimal thickness in the CAA group was significantly thinner than that in the non-CAA group （（146.6±94.8） μm vs. （192.5＋97.1）μm, P 〈0.001）, as detected via OCT. Patients with CAA formation had a higher frequency of cardiac events including angina pectoris （25.81% vs. 6.25%, P=0.001） and acute myocardial infarction （9.68% vs. 0.13%, P=0.002） and thrombosis （16.13% vs. 0.69%, P 〈0.001）. The longitudinal length of the CAA in the cardiac event group was significantly longer than in the no cardiac event group （（20.0±9.07） mm vs. （12.05±5.38） ram, P=0.005）. Conclusion CAA formation after DES implantation is frequently associated with cardiac events as a result of stent malapposition and incomplete neointimal coverage.

关键词： optical coherence tomography coronary artery aneurysms drug-eluting stent neointimal coverage

Function of chloride intracellular channel 1 in gastric cancer cells

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World Journal of Gastroenterology 2012年第24期18卷 3070-3080页

作者： Peng-Fei Ma Jun-Qiang Chen Zhen wang jin-Lu liu Bo-Pei Li Department of Gastrointestinal Surgery the First Affili- ated Hospital of Guangxi Medical University Nanning 530021 Guangxi Zhuang Autonomous Region China

AIM:To investigate the effect of chloride intracellular channel 1(CLIC1) on the cell proliferation,apoptosis,migration and invasion of gastric cancer ***:CLIC1 expression was evaluated in human gastric cancer cell lines SGC-7901 and MGC-803 by real time polymerase chain reaction(RT-PCR).Four segments of small interference RNA(siRNA) targeting CLIC1 mRNA and a no-sense control segment were designed by bioinformatics ***1 siRNA was selected using Lipofectamine 2000 and transfected transiently into human gastric cancer SGC-7901 and MGC-803 *** transfected efficiency was observed under fluorescence *** transfection,mRNA expression of CLIC1 was detected with RT-PCR and Western blotting was used to detect the protein *** was examined by methyl thiazolyl tetrazolium and apoptosis was detected with flow *** membrane transwell chamber and Matrigel were used for the detection of the changes of invasion and migration of the two cell ***:In gastric cancer cell lines SGC-7901 and MGC-803,CLIC1 was obviously expressed and CLIC1 siRNA could effectively suppress the expression of CLIC1 protein and *** of cells transfected with CLIC1 siRNA3 was enhanced notably,and the highest proliferation rate was 23.3%(P = 0.002) in SGC-7901 and 35.55%(P = 0.001) in MGC-803 cells at 48 *** G2/M phase proportion increased,while G0/G1 and S phase proportions *** apoptotic rate of the CLIC1 siRNA3 group obviously decreased in both SGC-7901 cells(62.24%,P = 0.000) and MGC-803 cells(52.67%,P = 0.004).Down-regulation of CLIC1 led to the inhibition of invasion and migration by 54.31%(P = 0.000) and 33.62%(P = 0.001) in SGC-7901 and 40.74%(P = 0.000) and 29.26%(P = 0.002) in ***,there was no significant difference between the mock group cells and the negative control group cells.

关键词： Chloride intracellular channel 1 Gastric car-cinoma Small interference RNA Apoptosis Invasion Migration