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Hydrodynamical simulations of the triggering of nuclear activities by minor mergers of galaxies

Research in Astronomy and Astrophysics 2019年第12期19卷 245-256页

作者： Chao Yang jun-Qiang Ge you-jun Lu National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory for Computational Astrophysics National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

Major mergers of galaxies are considered to be an efficient way to trigger Active Galactic Nuclei and are thought to be responsible for the phenomenon of quasars. This has however recently been challenged by observations of a large number of low luminosity Active Galactic Nuclei at low redshift(z■1) without obvious major merger signatures. Minor mergers are frequently proposed to explain the existence of these Active Galactic Nuclei. In this paper, we perform nine high resolution hydrodynamical simulations of minor galaxy mergers, and investigate whether nuclear activities can be efficiently triggered by minor mergers, by setting various properties for the progenitor galaxies of those mergers. We find that minor galaxy mergers can activate the massive black hole in the primary galaxy with an Eddington ratio of f Edd > 0.01 and> 0.05(or a bolometric luminosity > 10^43 and > 10^44 erg s^-1) with a duration of 2.71 and 0.49 Gyr(or 2.69 and 0.19 Gyr), respectively. The nuclear activity of the primary galaxy strongly depends on the nucleus separation, such that the nucleus is more active as the two nuclei approach each other. Dual Active Galactic Nuclei systems can still possibly be formed by minor mergers of galaxies, though the time duration for dual Active Galactic Nuclei is only ~ 0.011 Gyr and ~ 0.017 Gyr with Eddington ratio of f Edd > 0.05 and bolometric luminosity > 10^44 erg s^-1. This time period is typically shorter than that of dual Active Galactic Nuclei induced by major galaxy mergers.

关键词： galaxies:binary quasars:general methods:n-body simulations

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Investigating the co-evolution of massive black holes in dual active galactic nuclei and their host galaxies via galaxy merger simulations

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Science China(Physics,Mechanics & Astronomy) 2019年第12期62卷 96-109页

作者： Chao Yang junQiang Ge you jun Lu National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Key Laboratory for Computational Astrophysics National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China

Major galaxy mergers can trigger nuclear activities and are responsible for high-luminosity quasi-stellar objects/active galactic nuclei(QSOs/AGNs). In certain circumstances, such mergers may cause dual active galactic nuclei(dAGN) phenomenon. This study investigates dAGN triggering and evolution of massive black holes(MBHs) during the merging processes using hydrodynamic code GADGET-2 to simulate several gas-rich major mergers at redshift z = 2 and 3, respectively. Results reveal that gas-rich major mergers can trigger significant nuclear activities after the second and third pericentric passages and the formation of dAGN with significant time duration(~10-390 Myr). During the merging processes, galactic bulge evolves with time because of the rapid star formation in each(or both) galactic centers and initial mixing of stars in galactic disks due to violent *** grow substantially due to accretion and finally merge into a bigger black hole. The growth of galactic bulges and corresponding increases of its velocity dispersions predate the growth of MBHs in the d AGN stages. The MBHs in these stages deviate below the relation between MBH mass and bulge mass(or velocity dispersion), and they revert to the relation after the final mergers due to the significant accretion that occurs mostly at a separation less than a few kpc. Then, the two MBHs merge with each other.

关键词： galaxies quasars black hole numerical simulations

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Size prediction of κ-carrageenan droplets formed in co-flowing immiscible liquid

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Particuology 2011年第6期9卷 637-643页

作者： jun-Yee Leong Tek-Kaun Lim Ravindra Pogaku eng-Seng Chan Centre of Materials and Minerals School of Engineering and Information Technology Universiti Malaysia Sabah School of engineering Monash University

The formation of K-carrageenan droplets in channel emulsification was experimentally investigated. The dispersed phase was vertically injected into co-flowing immiscible palm oil in the direction of gravity. This study focused on predicting K-carrageenan drop size using force balance analysis. The force balance model considers the interracial tension to be the solitary attaching force, while a combination of the drag force from the co-flowing palm oil and the body force of the extruding K-carrageenan liquid act as the detaching forces. The conventional model gave poor predictions for droplet size, with an average relative deviation of 23%. This large deviation could be attributed to necking phenomena and an underestimation of the drag force generated on the shear-thinning K-carrageenan solution. By incorporating correction factors, the average relative deviation of the force balance model dronned to 4%.

关键词： K-Carrageenan Droplet Channel emulsification Co-flowing Dripping Bioencapsulation

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CoMFA Study on Anti-proliferative Activity of Fluoroquinolone Amide Derivatives

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Chinese Journal of Structural Chemistry 2022年第3期41卷 241-247,I0014页

作者： eng Hui CAO Jing-Pei Feng Chang-jun School of Chemical engineering and Technology China University of Mining and TechnologyXuzhou 221116China Key Laboratory of Coal Processing and Efficient Utilization(Ministry of Education) Xuzhou 221116China School of Material&Chemical engineering Xuzhou University of TechnologyXuzhou 221018China

The in vitro anti-proliferative activity(pICi,i=hp,ca,hl)of fluoroquinolone(rhodanineα,β-unsaturated ketone)amide compounds,referred to as“fluoroquinolone amide derivatives(FQADs)”towards Hep-3B,Capan-1 and HL60 cells,was studied by the 3D-QSAR method of comparative molecular field analysis(CoMFA).Based on the training set of 14 compounds,the prediction model was established,which was further verified by the test set of 5 compounds with template molecule *** is found that steric and electrostatic fields contribute 66.8%and 33.2%to pIChp,61.4%and 38.6%to pICca,and 61.5%and 38.5%to pIChl,*** Rcv 2(i.e,cross-validation coefficient)is 0.324,0.381,and 0.421 for pIChp,pICca,and pIChl,respectively,while the corresponding R2(i.e,non-cross-validation coefficient)all reach ***,the models were employed to estimate the activities of the training and test compounds,and the results show that the stability and predictability of developed models are very *** to the contour maps of steric and electronic fields,bulky groups linked to 2-,3-,4-positions of phenyl ring,and electropositive groups near the 4-position and electronegative groups far away may increase the anti-proliferative *** the information provided by the 3D contour maps,four new FQADs owing higher antiproliferative activity were designed,but their effectiveness should be further tested by experiments.

关键词： fluoroquinolone amide derivatives Hep-3B cell Capan-1cell HL60 cell anti-proliferative activity comparative molecular field analysis

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Moment Redistribution Effect of the Continuous Glass Fiber Reinforced Polymer-Concrete Composite Slabs Based on Static Loading Experiment

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Structural Durability & Health Monitoring 2025年第1期19卷 105-123页

作者： zhao-jun zhang Wen-Wei Wang Jing-Shui zhen Bo-Cheng Li De-Cheng Cai Yang-Yang Du Hui Huang Offshore Oil engineering Co.Ltd. Tianjin300461China Department of Bridge engineering School of TransportationSoutheast UniversityNanjing211189China

This study aimed to investigate the moment redistribution in continuous glass fiber reinforced polymer(GFRP)-concrete composite slabs caused by concrete cracking and steel bar yielding in the negative bending moment *** experimental bending moment redistribution test was conducted on continuous GFRP-concrete composite slabs,and a calculation method based on the conjugate beam method was *** composite slabs were formed by combining GFRP profiles with a concrete layer and supported on steel beams to create two-span continuous composite slab *** methods,epoxy resin bonding,and stud connection,were used to connect the composite slabs with the steel *** experimental findings showed that the specimen connected with epoxy resin exhibited two moments redistribution phenomena during the loading process:concrete cracking and steel bar yielding at the internal *** contrast,the composite slab connected with steel beams by studs exhibited only one-moment redistribution phenomenon throughout the loading *** the concrete at the internal support cracked,the bending moment decreased in the internal support section and increased in the midspan *** the steel bars yielded,the bending moment further decreased in the internal support section and increased in the mid-span *** GFRP profiles do not experience cracking,there was no significant decrease in the bending moment of the mid-span *** test specimens experienced compressive failure of concrete at the mid-span *** results showed good agreement between the calculated and experimental values of bending moments in the mid-span section and internal support *** proposed model can effectively predict the moment redistribution behavior of continuous GFRP-concrete composite slabs.

关键词： Moment redistribution GFRP-concrete composite slabs bending moment experimental study analysis model

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Study of the properties of non-gas dielectric capacitors in porous media

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Petroleum Science 2015年第1期12卷 104-113页

作者： Hong-Qi Liu Yan jun you-Ming Deng State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum University Centrica Energy (E&P) Upstream Kings Close

The size of pores and throats is at the nano- meter scale in tight oil and shale gas zones, and the resistivity of these reservoirs is very high, so the reservoirs show more dielectric properties than conductivity proper- ties. The conductive and dielectric characteristics of a parallel plate capacitor full of fresh water, NaCl solutions, and solid dielectrics, for example, sands are investigated in this paper, and the capacitance data of the non-gas capacitor are measured at different salinities and frequencies by a spectrum analyzer. The experimental results illustrate that the capacitance of this kind of capacitor is directly pro- portional to the salinity of the solutions and inversely proportional to the measuring frequency, the same as a vacuum parallel plate capacitor. The remarkable phenom- enon, however, is that the capacitance is inversely pro- portional to the square of the distance between two plates. The specific characteristic of this capacitor is different from the conventional parallel plate capacitor. In order to explain this phenomenon, the paper proposed a new concept, named ＂single micro ion capacitor＂, and established a novel model to describe the characteristics of this particular capacitor. Based on this new model, the theoretical capacitance value of the single micro ion capacitor is calculated, and its polarization and relaxation mechanisms are analyzed.

关键词： NaCl solution Debye model Single micro ion capacitor Dielectrics Micro capacitivity

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Characteristics of biomarker in source rocks of Linxi Formation in Taohaiyingzi region, zhalute basin

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Chinese Journal Of Geochemistry 2015年第3期34卷 338-345页

作者： Li Liu you-jun Tang Xing-chao Jiang Key Laboratory of Exploration Technologies for Oil and Gas Resources Ministry of Education School of Earth Environment and Water Resources Yangtze University

Based on gas chromatography and gas chromatography mass spectrometry techniques, the authors researched biomarker characteristics of the Linxi Formation source rocks in the area of Taohaiyingzi, and analyzed the information and petroleum geological significance that were indicated by source of organic matter, sedimentary environment, maturity and so on. Gas chromatography peak of saturated hydrocarbons from Linxi Formation source rocks showed ‘‘the former peak'' of the single peak distribution and the C23-dominant main peak. This indicates that the main source of organic matter was mixed organic matter; Pr/Ph ratios ranged from 0.3 to 0.6, indicating a strongly reducing sedimentary *** fossil assemblages in Linxi Formation source rocks were abundant in tricyclic terpane with long side chains, had high level of gammacerane, and showed dominant distribution of C27 steranes. Gammacerane ratios range from 0.15 to 0.29, with an average of 0.19, implying that Linxi Formation hydrocarbon source rocks were formed in the environment of micro-saltwater water to half-saltwater water. The hopanes/steranes ratios are mainly between 0.6 and 1.0, with an average of 0.84, implying that bacteria and algae had almost the samecontribution to organic matter. C27 steranes abundance is high and the ratio of C27steranes/C29 steranes is 1.13,showing that algae is the main source of hydrocarbon precursors.

关键词：生物标志物烃源岩特征比值范围盆地石油地质意义气相色谱沉积环境

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The reionization of He II and the temperature evolution of the intergalactic medium

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Research in Astronomy and Astrophysics 2014年第4期14卷 373-389页

作者： Yun-Chuan Yu Chang-Shuo Yan you-jun Lu National Astronomical Observatories Chinese Academy of Sciences

A number of observations suggest that He II in the intergalactic medium （IGM） was fully ionized at z-3, probably by quasi-stellar objects （QSOs）. Here we construct a simple model of a QSO to study the reionization of He II and the corre- sponding thermal evolution of the IGM. We assume that QSOs are triggered by major mergers of dark matter halos, and the luminosity evolution of individual QSOs is de- scribed by an initial accretion stage with a constant Eddington ratio and then a power- law decay driven by long term disk evolution or fueling. Once a QSO is triggered, it immediately ionizes its surrounding area as an ionized bubble. The resulting changes in size and volume of the bubble are determined by the luminosity evolution of the central QSO. With the emergence of more and more bubbles, they eventually over- lap each other and finally permeate the whole universe. During the He II reionization, the IGM temperature increases due to the photoheating by the ionization processes. Applying the bubble model and considering various heating and cooling mechanisms, we trace the thermal evolution of the IGM and obtain the average IGM temperature as a function of redshift, which is very consistent with observations. The increase in IGM temperature due to the reionization of He II may be determined more accurately in the future, which may put robust constraints on the QSO model and the physics of He II reionization.

关键词： cosmology: theory -- intergalactic medium: QSO

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A New zn(Ⅱ) Coordination Polymer Constructed by 1,4-Benzenedithiolate Dianion: [zn(SC_6H_4S)(1,3-DPA)]_n

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Chinese Journal of Structural Chemistry 2015年第6期34卷 911-916页

作者： YAO Hua-Gang zHANG jun-jun CAI zhang-Wei zHANG Chen-Yang you Li-jun z.eng Shuang School of Chemistry and Chemical engineering Guangdong Pharmaceutical University

A new one-dimensional polymer, [zn（SC6H4S）（1,3-DPA）]n （1, SC6H4S = 1,4-ben- zenedithiolate and 1,3-DPA = 1,3-diaminepropane）, has been synthesized and characterized by elemental analysis, PXRD, IR spectra, and single-crystal X-ray diffraction. The complex crystallizes in triclinic system, space group P1, with a = 6.7119（1）, b = 9.0230（2）, c = 10.4943（2） A, a = 69.288（1）, β = 75.848（1）, ）, = 81.513（1）°, V= 575.123（19） A3, Dc = 1.615 g/cm^3, z = 2, F（000） = 288; the final S = 1.070, R = 0.0234, and wR = 0.0551. The compound consists of an infinite zigzag chain formed by [zn（1,3-DPA）]^2＋ units joined by SC6H4S ligands. Each chain interacts with neighboring chains via weak N-H…S hydrogen bonds to form an extended three-dimensional （3D） supramolecular network. The thermal and photoluminescent properties of 1 have also been investigated.

关键词： zn(Ⅱ ) coordination polymer crystal structure 1,4-benzenedithioi zigzag chain

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Structure and Properties of Gel-spun Ultra-high Molecular Weight Polyethylene Fibers with High Gel Solution Concentration

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Chinese Journal of Polymer Science 2017年第4期35卷 524-533页

作者： Min-fang An you Lv Hao-jun Xu Qun-Gu 王宗宝 Ningbo Key Laboratory of Specialty Polymers Faculty of Materials Science and Chemical Engineering Ningbo University Ningbo 315211 China College of Material engineering Ningbo University of Technology Ningbo 315211 China

The gel-spun ultra-high molecular weight polyethylene （UHMWPE） fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultimate structure and mechanical properties of UHMWPE fibers for different gel solution concentrations were analyzed by tensile testing, differential scanning calorimetry （DSC）, wide angle X-ray diffraction （WAXD） and small angle X-ray scattering （SAXS）. With the increase of gel solution concentration, the ultimate mechanical properties of UHMWPE fibers were decreased and the crystallization and orientation of UHMWPE fibers became inferior. Besides, both the average shish length （（Lshsh）） and shish misorientation （B0） of UHMWPE fibers were decreased with the increase of gel solution concentration. In addition, the appropriate increase of spinning temperature led to the further optimization of the ultimate structure and mechanical properties of UHMWPE fibers.

关键词： UHMWPE fibers Gel solution concentration Orientation Crystallization Shish structure

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