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Search for gamma-ray line signals around the black hole at the galactic center with DAMPE observation

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Science China(Physics,Mechanics & Astronomy) 2022年第6期65卷 150-158页

作者： Tian-Ci Liu Ji-gui Cheng Yun-Feng liang En-Wei liang Laboratory for Relativistic Astrophysics Department of PhysicsGuangxi UniversityNanning 530004China

The adiabatic growth of a black hole(BH)may enhance the dark matter(DM)density surrounding it,causing a spike in the DM density *** spike around the supermassive BH at the center of the Milky Way may lead to a dramatic enhancement of the gamma-ray flux of DM annihilation from the galactic center(GC).In this work,we analyze the gamma-ray data of the innermost region(i.e.,the inner 1°)of the GC to search for potential line-like signals from the BH *** line-like signals could be generated in the process of DM particles annihilating into double *** adopt the gamma-ray data from the Dark Matter Particle Explorer(DAMPE).Although the DAMPE has a much smaller effective area than the Fermi-LAT,the gamma-ray line search can benefit from its unprecedented high energy *** significant line-like signals are found in our *** derive upper limits on the cross section of the annihilation based on this *** find that despite the DAMPE’s small effective area for photon detection,we can still place strong constraints on the cross section(≥10^(-27)cm^(3)s^(-1))in the spike scenario due to the very bright model-expected flux from the *** results indicate that either DM does not annihilate primarily through theγγchannel in the mass range we considered or no sharp density spike is present at the GC.

关键词： dark matter γ-ray telescopes black holes galactic center

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Phenological Complementarity Does not Enhance Ecosystem Production in Undisturbed Steppe Community

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Journal of Integrative Plant Biology 2007年第5期49卷 582-587页

作者： liang Zhao gui-Xia Yang Zhong-Ling Liu xiao-Ping Xin Yan-Jiang LUO Gang Wang Key Laboratory of Arid and Grassland Ecology at Lanzhou University Ministry of Education Lanzhou 730000 China Key Laboratory of Resources Remote Sensing and Digital Agriculture Ministry of Agriculture Beijing 100083 China Inner Mongolia University Huhhot 010021 China

Communities with more species could have a greater variety of species＇ characteristics, leading to more effective use of limiting resources through niche partitioning （complementarity） and therefore greater production. The effect of phenologlcal complementarity （PC） on ecosystem production has not been fully Investigated. The seasonal responses of all vascular plant species were tracked to test the effect of phenologlcal complementarity on ecosystem production within a natural stable steppe community. Although a significant phenologlcal pattern was observed, PC had no significant correlation with community production. The value of PC varied with years, but was observed only In a relatively narrow range during the experimental period. Species diversity （richness and evenness） had no correlation with the ecosystem production. The results suggest that the effect of PC may be saturated and has no contribution to the improvement of ecosystem production In a stable natural grassland community with abundant species.

关键词： ecosystem function phenological complementarity steppe community temporal variation total annual net primary productivity.

Domain Knowledge Used in Meta-Heuristic Algorithms for the Job-Shop Scheduling Problem:Review and Analysis

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Tsinghua Science and Technology 2024年第5期29卷 1368-1389页

作者： Lin gui Xinyu Li Qingfu Zhang liang Gao State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Department of Computer Science City University of Hong KongHong KongChina

Meta-heuristic algorithms search the problem solution space to obtain a satisfactory solution within a reasonable *** combining domain knowledge of the specific optimization problem,the search efficiency and quality of meta-heuristic algorithms can be significantly improved,making it crucial to identify and summarize domain knowledge within the *** this paper,we summarize and analyze domain knowledge that can be applied to meta-heuristic algorithms in the job-shop scheduling problem(JSP).Firstly,this paper delves into the importance of domain knowledge in optimization algorithm *** that,the development of different methods for the JSP are reviewed,and the domain knowledge in it for meta-heuristic algorithms is summarized and *** of this domain knowledge are analyzed,showing it is indispensable in ensuring the optimization performance of meta-heuristic ***,this paper analyzes the relationship among domain knowledge,optimization problems,and optimization algorithms,and points out the shortcomings of the existing research and puts forward research *** paper comprehensively summarizes the domain knowledge in the JSP,and discusses the relationship between the optimization problems,optimization algorithms and domain knowledge,which provides a research direction for the metaheuristic algorithm design for solving the JSP in the future.

关键词： domain knowledge job-shop scheduling problem meta-heuristic algorithm

Delayed Fracture Resistance and Mechanical Properties of 30MnSi High Strength Steel

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Journal of Iron and Steel Research International 2009年第3期16卷 49-54页

作者： xiao gui-zhi DI Hong-shuang The State Key Laboratory of Rolling Technology and Automation Northeastern UniversityShenyang 110004 Liaoning China

To investigate the effect of heat treatment on mechanical properties and delayed fracture resistance of high strength steel,30MnSi prestressed concrete （PC） steel bars are quenched and tempered. Tensile results show that,after 950 ℃ quenching and about 430 ℃ tempering,30MnSi PC steel bars have superior mechanical properties and delayed fracture resistance. Microstructural observation shows that 30MnSi steel bar is mainly composed of fine tempered sorbite （troostite） with carbide distributed along the lath martensite boundaries. It can be concluded that thermal refining is an effective way to improve mechanical properties and delayed fracture resistance of 30MnSi PC steel bar.

关键词： delayed fracture quenching tempering mechanical property PC steel bar

Carbon Monoxide-induced Stomatal Closure Involves Generation of Hydrogen Peroxide in Vicia faba Guard Cells

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Journal of Integrative Plant Biology 2008年第12期50卷 1539-1548页

作者： xiao-Ping She Xi-gui Song School of Life Sciences Shaanxi Normal University Xi'an 710062 China

Here the regulatory role of CO during stomatal movement in Vicia faba L. was surveyed. Results indicated that, like hydrogen peroxide （H2O2）, CO donor HemaUn induced stomatal closure in dose- and time-dependent manners. These responses were also proven by the addition of gaseous CO aqueous solution with different concentrations, showing the first time that CO and H2O2 exhibit the similar regulation role in the stomatal movement. Moreover, our data showed that ascorbic acid （ASA, an important reducing substrate for H2O2 removal） and diphenylene iodonium （DPI, an inhibitor of the H2O2-generating enzyme NADPH oxidase） not only reversed stomatal closure by CO, but also suppressed the H2O2 fluorescence induced by CO, implying that CO induced-stomatal closure probably involves H2O2 signal. Additionally, the CO/NO scavenger hemoglobin （Hb） and CO specific synthetic inhibitor ZnPPIX, ASA and DPI reversed the darkness-induced stomatal closure and H2O2 fluorescence. These results show that, perhaps like H2O2, the levels of CO in guard cells of V. faba are higher in the dark than in light, HO-1 and NADPH oxidase are the enzyme systems responsible for generating endogenous CO and H2O2 in darkness respectively, and that CO is involved in darkness-induced H2O2 synthesis in V. faba guard cells.

关键词： carbon monoxide guard cells hydrogen peroxide signaling stomata.

Note on Integer 4-flows in Graphs

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Acta Mathematica Sinica,English Series 2022年第9期38卷 1653-1664页

作者： xiao WANG You LU Sheng gui ZHANG School of Mathematics and Statistics Northwestern Polytechnical UniversityXi'an 710072P.R.China College of Mathematics and Computer Application Shangluo UniversityShangluo 726000P.R.China

Let G be a bridgeless graph and C be a circuit in *** find a shorter circuit cover of G,Fan proposed a conjecture that if G/C admits a nowhere-zero 4-flow,then G admits a 4-flow(D,f)such that E(G)E(C)?supp(f)and|supp(f)∩E(C)|>3/4|E(C)|,and showed that the conjecture holds if|E(C)|≤19[Combinatorica,37,1097–1112(2017)].In this paper,we prove that the conjecture holds if|E(C)|≤27.

关键词： Integer 4-flow modulo 4-flow circuit

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Causal gene identification and desirable trait recreation in goldfish

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Science China(Life Sciences) 2022年第12期65卷 2341-2353页

作者： Peng Yu Yang Wang Zhi Li Hui Jin liang-liang Li xiao Han Zhong-Wei Wang xiao-Li Yang Xi-Yin Li xiao-Juan Zhang Li Zhou Jian-Fang gui State Key Laboratory of Freshwater Ecology and Biotechnology Hubei Hongshan LaboratoryThe Innovation Academy of Seed DesignInstitute of HydrobiologyChinese Academy of SciencesWuhan 430072China University of Chinese Academy of Sciences Beijing 100049China

Goldfish(Carassius auratus) have long fascinated evolutionary biologists and geneticists because of their diverse morphological and color *** genome-wide association studies have provided a clue to uncover genomic basis underlying these phenotypic variations,but the causality between phenotypic and genotypic variations have not yet been ***,we edited proposed candidate genes to recreate phenotypic traits and developed a rapid biotechnology approach which combines gene editing with high-efficiency breeding,artificial gynogenesis,and temperature-induced sex reversal to establish homozygous mutants within two generations(approximately eight months).We first verified that low-density lipoprotein receptorrelated protein 2B(lrp2a B) is the causal gene for the dragon-eye variation and recreated the dragon-eye phenotype in side-view Pleated-skirt Lion-head ***,we demonstrated that the albino phenotype was determined by both homeologs of oculocutaneous albinism type II(oca2),which has subfunctionalized to differentially govern melanogenesis in the goldfish body surface and ***,we determined two causal genes for dragon-eye and albino phenotypes,and created four stable homozygous strains and more appealing goldfish with desirable *** developed biotechnology approach facilitates precise genetic breeding,which will accelerate re-domestication and recreation of phenotypically desirable goldfish.

关键词： goldfish precise molecular design breeding re-domestication gene editing ornamental traits dragon-eye albino

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FUZZY SYNTHETIC EVALUATION ON RESIDENT'S PERCEPTIONS OF TOURISM IMPACTS——Case of Jiuzhaigou National Park, Sichuan Province, China

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Chinese Geographical Science 2006年第1期16卷 87-94页

作者： LU xiao-li WU Chun-you xiao gui-rong School of Management Dalian University of Technology Dalian 116024 P.R.China Eaculty of Geography Environmental Studies University of Waterlao Ontaria Canada N2L 3G1

Tourism can have both positive and negative outcomes for residents in tourism destinations, It is a good method to analyze the status of tourism impact by means of investigating residents＇ perceptions of it. Various methods have been used in previous authoritative studies. However, owing to inherent imprecision, difficulties always exist in some conventional methodologies when describing the interpretation of linguistic or measured uncertainties for real-world randoln phenomena. The purpose of this research is to present the fuzzy synthetic evaluation method to investigate residents＇ perceptions of tourisln impacts. At first, basic attributes and a hierarchical framework of tourism impacts are defined and formed. Secondly, the weighted vectors are determined according to the knowledge and experience of experts. Thirdly, the weighted evaluation matrices are aggregated to get the fuzzy sets of tourism impacts. In the last stage, the final fuzzy sets are defuzzified to get the rank of the residents＇ perceptions of tourism impacts. A case study in Jiuzhaigou National Park of China is provided to demonstrate the application of this method.

关键词： residents' perceptions tourism impacts fuzzy synthetic evaluation Jiuzhaigou National Park

A Fluorine-Functionalized 3D Covalent Organic Framework with Entangled 2D Layers

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Chinese Journal of Polymer Science 2024年第8期42卷 1210-1216页

作者： Li-Bang xiao Zi-Han Wu Jun-Jie Xin Yuan-Peng Cheng Bo gui Jun-liang Sun Cheng Wang College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072China College of Chemistry and Molecular Engineering Beijing National Laboratory for Molecular SciencesPeking UniversityBeijing 100871China

Constructing three dimensional(3D)covalent organic frameworks(COFs)through the entanglement of two dimensional(2D)nets is a promising but underdeveloped ***,we report the design and synthesis of a fluorine functionalized 3DCOF(3D-An-COF-F)formed by entangled 2D sql *** structure of 3D-An-COF-F was determined by the combination of continuous rotation electron diffraction technique and modelling based on the chemical information from real ***,compared to the isostructural 3D-An-COF without F atom s,3DAn-COF-F showed an improved CO_(2)sorption ability and higher CO_(2)/N_(2)*** study not only demonstrated the generality of constructing 3D COFs with entangled 2D nets by introducing bulky groups vertically in planar building blocks,but also will expand the diversity of 3D COFs for various applications.

关键词： 3D covalent organic frameworks Fluorine Entangled 2D layers Electron diffraction CO_(2)adsorption