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Possibility of measuring spin precession of the nearest supermassive black hole by using S stars

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Research in Astronomy and Astrophysics 2014年第11期14卷 1415-1422页

作者： Wen-biao han Shanghai Astronomical Observatory

The supermassive black hole （SMBH） with a mass of 4 million M⊙ inside the radio source Sgr A＊ in our Galactic center is the nearest SMBH. Once S stars with a shorter period are observed, relativistic precessions especially the Lense-Thirring effect can be measured by astronomical observations at the 10 ~tas level in the future. An interesting but so far unaddressed problem is that the SMBH not only has spin but also spin precession like similar objects. We study the effect of such spin precession on the orbital precessions of orbiting stars. Our results show that the spin precession can produce a periodic oscillation in the precession of the star＇s orbital plane, but has no obvious effect on the periapse shift. For stars with an orbital period of O（0.1） yr or less, such visible oscillations occur when the SMBH＇s spin-precession period ranges from about a few tens of years to hundreds of years. The period of oscillation is the same as the one of the spin precession. In principle, the precession of this oscillating orbital plane can be observed and then the spin and spin precession of the nearest SMBH can be determined.

关键词： black hole physics -- Galaxy center -- relativity

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抓住机遇以评促建提高本科教学质量

河北科技大学学报（社会科学版） 2007年第3期7卷 102-105页

作者：韩鹏彪毛磊张立忠张会敏于玲河北科技大学河北石家庄050018

教育部本科教学工作水平评估对促进高等教育教学质量和水平的提高具有重要意义。在学校的统一部署下,我校材料科学与工程学院以评估为发展与建设契机,认真践行"以评促建"原则,系统规划,认真做好顶层设计;坚持过程与目标并重,实现评建工... 详细信息

教育部本科教学工作水平评估对促进高等教育教学质量和水平的提高具有重要意义。在学校的统一部署下,我校材料科学与工程学院以评估为发展与建设契机,认真践行"以评促建"原则,系统规划,认真做好顶层设计;坚持过程与目标并重,实现评建工作的"三个结合";落实科学发展观,建立提高教学质量的长效机制,不断提升本科教育教学质量。

关键词：教学评估本科教学质量以评促建长效机制

General formalism for dirty extreme-mass-ratio inspirals

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 22-29页

作者： Ye Jiang Wen-biao han Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China Shanghai Frontiers Science Center for Gravitational Wave Detection Shanghai 200240China

Detecting the environment around the supermassive black holes and tests of general relativity are important applications of extreme-mass-ratio inspirals(EMRIs).There is still a challenge to efficiently describe various“dirty”impacts on the inspirals,such as dark matter,gas,dipole radiation,and electromagnetic *** this study,we find the inherent linearity of the asymptotic solution of the inhomogeneous Teukolsky *** the basis of this property,we completely decouple the factors of the perturber and the background spacetime in the energy fluxes and *** the new decoupling form,the waveforms of EMRIs with non-geodesic motion in Kerr spacetime can be conveniently *** will help to resolve the environment(including gas,field,dark matter,electromagnetic interaction)around supermassive black holes and test general relativity.

关键词： gravitational wave Teukolsky equation extreme-mass-ratio inspirals

Dense 3-uniform hypergraphs containing a large clique

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Science China Mathematics 2018年第3期61卷 577-592页

作者： biao Wu Yuejian peng College of Mathematics and Econometrics Hunan University Institute of Mathematics Hunan University

An r-uniform graph C is dense if and only if every proper subgraph G' of G satisfies λ(G') < λ(G).,where λ(G) is the Lagrangian of a hypergraph G. In 1980's, Sidorenko showed that π(F), the Turán density of an γ-uniform hypergraph F is r! multiplying the supremum of the Lagrangians of all dense F-hom-free γ-uniform hypergraphs. This connection has been applied in the estimating Turán density of hypergraphs. When γ=2 the result of Motzkin and Straus shows that a graph is dense if and only if it is a complete graph. However,when r ≥ 3, it becomes much harder to estimate the Lagrangians of γ-uniform hypergraphs and to characterize the structure of all dense γ-uniform graphs. The main goal of this note is to give some sufficient conditions for3-uniform graphs with given substructures to be dense. For example, if G is a 3-graph with vertex set [t] and m edges containing [t-1]^(3),then G is dense if and only if m≥{t-2 3)+(t-2 2)+1. We also give a sufficient condition on the number of edges for a 3-uniform hypergraph containing a large clique minus 1 or 2 edges to be dense.

关键词： dense hypergraphs Lagrangian of hypergraphs Turan density

The Maximum Lagrangian of 5-uniform Hypergraphs without Containing Two Edges Intersecting at a Vertex

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Acta Mathematica Sinica,English Series 2022年第5期38卷 877-889页

作者： biao WU Yue Jian peng MOE-LCSM School of Mathematics and StatisticsHu’nan Normal UniversityChangsha 410081P.R.China School of Mathematics Hu’nan UniversityChangsha 410082P.R.China

Obtaining Turán densities of hypergraph through determining Lagrangian densities have been studied *** showed that the Lagrangian density of an r-uniform hypergraph equals the Turán density of the extension of this ***,Lagrangian density and Turán density are the same for a large class of hypergraphs such as hypergraphs covering *** Pr,sbe the r-uniform hypergraph with two edges intersecting at s *** determined the Lagrangian densities of Pr,sfor r=3 and s=1 or 2,or r=4 and s=2 or *** and Keevash determined for r=3 and s=0,and Bene Watts,Norin and Yepremyan determined for r≥4 and s=*** cases r=5 and s=4 or r=6 and s=5 were determined by Norin and *** showed for r=5,6 or 7,and s=3,4 or 5 *** cases r=4 and s=1 or r=5 and s=2 were determined by Jiang,peng and Wu,and Hu,peng and Wu *** r=5,the only remaining case is s=*** this paper,we determine for this case.

关键词： Hypergraph Lagrangian Turán number

An improved artificial bee colony algorithm for steelmaking–refining–continuous casting scheduling problem

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Chinese Journal of Chemical Engineering 2018年第8期26卷 1727-1735页

作者： Kunkun peng Quanke Pan biao Zhang State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology

Steelmaking–refining–Continuous Casting(SCC) scheduling is a worldwide problem, which is NP-hard. Effective SCC scheduling algorithms can help to enhance productivity, and thus make significant monetary savings. This paper develops an Improved Artificial Bee Colony(IABC) algorithm for the SCC scheduling. In the proposed IABC, charge permutation is employed to represent the solutions. In the population initialization, several solutions with certain quality are produced by a heuristic while others are generated randomly. Two variable neighborhood search neighborhood operators are devised to generate new high-quality solutions for the employed bee and onlooker bee phases, respectively. Meanwhile, in order to enhance the exploitation ability, a control parameter is introduced to conduct the search of onlooker bee phase. Moreover, to enhance the exploration ability,the new generated solutions are accepted with a control acceptance criterion. In the scout bee phase, the solution corresponding to a scout bee is updated by performing three swap operators and three insert operators with equal probability. Computational comparisons against several recent algorithms and a state-of-the-art SCC scheduling algorithm have demonstrated the strength and superiority of the IABC.

关键词： Artificial bee colony Steelmaking–refining–continuous casting Hybrid flowshop scheduling Variable neighborhood search

Comprehensive evaluation of chemical breakers for multistage network ultra-high strength gel

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Petroleum Science 2023年第5期20卷 2864-2878页

作者： Zheng Kang Hu Jia Zhong-Guo Li biao Xia Yi Wang Yong Jiang han-Lin peng Petroleum Engineering Technology Institute of Southwest Petroleum Branch SINOPECDeyang618000SichuanChina National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation of Southwest Petroleum University Chengdu610500SichuanChina SINOPEC Southwest Petroleum Engineering Company Deyang618000SichuanChina

Polymer gels have been accepted as a useful tool to address many sealing operations such as drilling and completion,well stimulation,wellbore integrity,water and gas shutoff,***,we developed an ultra-high strength gel(USGel)for medium to ultra-low temperature ***,the removal of USGel is a difficult problem for most temporary plugging *** paper first provides new insights into the mechanism of USGel,where multistage network structure and physical entanglement are the main reasons for USGel possessing ultra-high *** the effects of acid breakers,encapsulated breakers,and oxidation breakers(including H_(2)O_(2),Na_(2)S_(2)O_(8),Ca(ClO)_(2),H_(2)O_(2)+NaOH,Na_(2)S_(2)O_(8)+NaOH,and Ca(ClO)_(2)+NaOH)were *** effects of component concentration and temperature on the breaking solution were studied,and the corrosion performance,physical simulation and formation damage tests of the breaking solution were carried *** final formulation of 2%-4%NaOH+4.5%-6%H_(2)O_(2) breaking solution was determined,which can make USGel completely turn into water at 35e105*** combinations of“acid t breaking solution”,“acid+encapsulated breaker”and“encapsulated breaker+breaking solution”were evaluated for breaking *** acid gradually reduced the volume of USGel,which increased the contact area between breaking solution and USGel,and the effect of“4%acid+breaking solution”was 23 times higher than that of breaking solution alone at 35***,the acid significantly reduced the strength of *** paper provides new insights into the breaking of high-strength gels with complex network structures.

关键词： Gel breaking Polymer gel Ultra-high strength Chemical breakers Multistage network

Poverty alleviation through e-commerce:Village involvement and demonstration policies in rural China

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Journal of Integrative Agriculture 2021年第4期20卷 998-1011页

作者： peng Chao MA biao ZhanG Chen Administration and Management Institute Ministry of Agriculture and Rural AffairsBeijing 102208P.R.China School of Agricultural Economics and Rural Development Renmin University of ChinaBeijing 100872P.R.China Institute of Population and Labor Economics Chinese Academy of Social SciencesBeijing 100006P.R.China

The diffusion of e-commerce has played a significant role in recent rural economic development in China.E-commerce is also considered as an efficient channel to alleviate poverty in rural *** studies have investigated the contribution of e-commerce to agricultural development,yet it is lacking empirical evidence as to the effects of e-commerce on rural poverty *** the year of 2014,in order to develop rural e-commerce,Chinese government launched the National Rural E-commerce Comprehensive Demonstration *** gradual involvement policy offered a natural experiment for evaluation of *** on village-level survey data from rural China and Heckit method,our study finds that rural e-commerce has a significantly positive effect on rural ***,the effect is inverted U-shaped for the relative-poverty *** estimation of the propensity scores matching model confirms that the results are *** following policy recommendations are proposed:(1)policy support to rural e-commerce should prioritize the povertystricken *** doing so,the marginal income effects of e-commerce will be maximized.(2)Investment in internet infrastructure and establishment of human resources for e-commerce in rural areas will have spillover effects,increasing rural income through the"digital dividend".

关键词： poverty alleviation income National Rural E-commerce Comprehensive Demonstration Project Heckit method

Characteristics of Ore-forming Fluid of the Gaoshan Gold-Silver Deposit in the Longquan Area, Zhejiang Province and its Implications for the Ore Genesis

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Acta Geologica Sinica(English Edition) 2016年第4期90卷 1321-1340页

作者： JIANG biao WANG Chenghui CHEN Yuchuan WU Baogui LIAO peng CHEN Zhengle han Fengbin MLR Key Laboratory of Metallogeny and Mineral Assessment Institute of Mineral ResourcesChinese Academy of Geological SciencesBeijing 100037China Chinese Academy of Geological Sciences Beijing 100037China No.7 Geological Team of Zhejiang Province LishuiZhejiang 323000 Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081

The Gaoshan gold-silver deposit, located between the Yuyao-Lishui Fault and Jiangshan- Shaoxing fault in Longquan Area, occurs in the Suichang-Longquan gold-silver polymetallic metallogenic belt. This study conducted an investigation for ore-forming fluids using microthermometry, D-O isotope and trace element. The results show that two types of fluid inclusions involved into the formation of the deposit are pure liquid phase and gas-liquid phase aqueous inclusions. The homogenization temperature and salinity of major mineralization phase ranges from 156~C to 236~C （average 200~C） and 0.35% to 8.68% （NaCleqv）（average 3.68%）, respectively, indicating that the ore-forming fluid is characteristic of low temperature and low salinity. The ore- forming pressure ranges between in 118.02 to 232.13＂105 pa, and it is estabmiated that the ore- forming depth ranges from 0.39 to 0.77 km, indicating it is a hypabyssal deposit in genesis. The low rare earth elements content in pyrites, widely developed fluorite in late ore-forming stage and lack of chlorargyrite （AgCI）, indicates that the ore-forming fluid is rich in F rather than CI. The ratios of Y/ Ho, Zr/Hf and Nb/Ta of between different samples have little difference, indicating that the later hydrothermal activities had no effects on the former hydrothermal fluid. The chondrite-normalized REE patterns of pyrites from country rocks and ore veins are basically identical, with the characteristics of light REE enrichment and negative Eu anomalies, implying that the ore-forming fluid was oxidative and derived partly from the country rocks. The JD and jlSo of fluid inclusions in quartz formed during the main metallogenic stage range from -105%o to -69 %0 and -6.01%o to -3.81%o, respectively. The D-O isotopic diagram shows that the metallogenic fluid is characterized by the mixing of formation water and meteoric water, without involvement of magmatic water. The geological and geochemical characteristics of the Gaoshan gold-silver d

关键词： ore-forming fluid trace elements D-O isotope ore genesis Gaoshan glod-silver deposit