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The fractions of post-binary-interaction stars and evolved blue straggler stars on the red giant branch of globular clusters

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Research in Astronomy and Astrophysics 2021年第9期21卷 101-110页

作者： dan-dan Wei Bo Wang Hai-Liang Chen Hai-Feng Wang Xiao-Bo Gong dong-dong Liu Deng-Kai Jiang Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of ScienceKunming 650216China University of Chinese Academy of Science Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100101China South-Western Institute for Astronomy Research Yunnan UniversityKunming 650500China LAMOST

The red giant branch(RGB)of globular clusters(GCs)is home to some exotic stars,which may provide clues on the formation of multiple stellar populations in *** is well known that binary interactions are responsible for many exotic ***,it is important to understand what fraction of stars on the RGB of GCs is the result of binary *** this paper,we performed a binary population synthesis study to track the number of post-binary-interaction(post-BI)stars that appear on the RGB,with particular emphasis on the evolved blue straggler stars(E-BSSs).Assuming an initial binary fraction of nearly 50%,we find that about half of the objects on the RGB(called giants)underwent the binary interactions,and that E-BSSs account for around 10%of the giants in our standard *** also compare the properties of post-BI giants that evolved from different *** find that the initial orbital period and mass ratio distributions significantly affect the fraction of post-BI *** results imply that the non-standard stars from binary interactions provide a non-negligible contribution to the RGB stars in GCs,which should be considered in future investigations of the origin of multiple stellar populations.

关键词： blue stragglers stars:chemically peculiar globular clusters:general binaries:general

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CSS J075415.6+191052 and NW Leo: Two Contact Binaries at Different Evolutionary Stages

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Research in Astronomy and Astrophysics 2022年第2期22卷 118-127页

作者： Xu-dong Zhang Sheng-Bang Qian er-Gang Zhao Qi-Jun Zhi Ai-Jun dong Bin Zhang School of Physics and Electronic Science Guizhou Normal University550025 GuiyangChina Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025 GuiyangChina Yunnan Observatories Chinese Academy of Sciences(CAS)650216 KunmingChina University of Chinese Academy of Sciences(UCAS) 100049 BeijingChina

Multi-color light curves of CSS J075415.6+191052 and NW Leo are presented and the photometric solutions suggest that CSS J075415.6+191052 is an A-subtype contact binary with low mass ratio(q = 0.178) while NW Leo has a high mass ratio(q = 0.707). For CSS J075415.6+191052, the RI light curves show weakening around the left shoulder of the secondary minimum, which indicates that there may be a dark spot on the secondary component. However, the light curves of BV bands are totally symmetric. It is unreasonable if the dark spot is caused by magnetic activity or mass transfer between the two components. Therefore, weakening of the light curves in this contact binary is caused by something else. A possible explanation is mass transferring from the primary component to the common convective envelope through the inner Lagrangian point, and this part of the mass, for some reason, weakens the RI bands of light from the secondary component. O-C analysis of NW Leo reveals a cyclic period change with a modulation period of 4.7 yr, which may be caused by the light travel time effect of a third body. The positions of CSS J075415.6+191052 and NW Leo in the P–J′_(orb)diagram indicate that CSS J075415.6+191052 mainly abides by the angular momentum loss theory while NW Leo is dominated by the thermal relaxation oscillation theory.

关键词： (stars:)binaries:eclipsing stars:evolution stars:individual(CSS J075415.6+191052 NW Leo)

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Investigation on the vortical structures by the Liutex method in turbulent channels at Re_(τ)=180 with scalloped and triangular riblet control

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Journal of Hydrodynamics 2024年第1期36卷 35-52页

作者： Zhang-dan Yu Shang Jiang Hai-dong Yu Bi-yu Pang Xin dong Yi-qian Wang School of Mathematical Sciences Soochow UniversitySuzhou215006China Beijing Institute of Astronautical System Engineering Beijing100076China

Riblets are a series of small protrusions formed along the flow direction,which have been extensively studied as a passive turbulent drag reduction *** and numerical simulations have shown that well-designed riblets can significantly reduce drag in turbulent flows,making them highly promising and valuable for various *** this study,we focus on a scalloped riblet,which is designed by smoothly connecting two third-order polynomials,and thus the sharpness of the tip and the curvature of the valley can be well *** conduct direct numerical simulations of turbulent channel with smooth plate,scalloped riblet-mounted and triangular riblet-mounted *** in wall units of W^(+)=20 and height-width ratio ofγ=0.5 are selected for both riblet *** with the smooth plate case,the scalloped riblet case achieves an 8.68%drag reduction,while the triangular riblet case achieves a 4.79%drag *** obtained drag reduction rate of the triangular riblet is consistent with previous experiments and simulations,and the results indicate that the scalloped riblet is more effective in reducing drag and deserves further *** compare turbulent statistics of the scalloped riblet case with those of the triangular riblet *** mean velocity profiles of riblets are similar,but both the Reynolds shear stress and second-order statistics of velocity fluctuations and Liutex are significantly reduced in the scalloped riblets controlled turbulent channel,indicating that the scalloped riblet can more effectively suppress the spanwise and wall-normal turbulent intensity near the *** also compare the pre-multiplied spectra of streamwise velocity and streamwise Liutex component for the three cases to investigate the energy distribution and characteristics of Liutex *** Liutex vortex identification method is also utilized to analyze the instantaneous flow field,which provides insights into the flow field and could be bene

关键词： Liutex vector riblet drag reduction tip sharpness turbulent channel scalloped

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Vacuum joints of dispersion-strengthened copper and its applications in synchrotron radiation front end

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Nuclear Science and Techniques 2016年第6期27卷 74-78页

作者： Yong-Jun Li Song Xue Min Zhang dan-dan Jia dong-Bai Dou Yu Gao Shanghai Institute of Applied Physics Chinese Academy ofSciencesZhangJiangShanghai 201204China University of Chinese Academy of Sciences Beijing 100049China SKY Technology Development Co. LtdChinese Academyof SciencesShenyang 110179China

Masks are critical elements of synchrotron radiation front end that are exposed to high temperature and *** absorber material is typically comprised of dispersion-strengthened copper,which can retain high performance at elevated *** processes under vacuum,including brazing and electron beam welding,are novel approaches for prolonging the absorber and for reducing power *** mechanical properties of brazed joints and electron beam welded joints of dispersion-strengthened copper workpieces are evaluated by tensile testing at 20,100,and 200 *** testing results indicate that the tensile strength and elongation of both vacuum joints decrease with increasing *** to brazed joints,electron beam welded joints have higher tensile strength,better ductility,and more stable performance.A novel welded mask with a total length of 600 mm is presented and shown to be practical for use in the highest heat load front end in the Shanghai synchrotron radiation facility phase-Ⅱ beamline project.

关键词：上海同步辐射装置弥散强化铜焊接接头前端真空电子束焊接应用钎焊接头

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Mechanism of miR-21 via Wnt/β-catenin signaling pathway in human A549 lung cancer cells and Lewis lung carcinoma in mice

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Asian Pacific Journal of Tropical Medicine 2015年第6期8卷 478-483页

作者： dan Wu Min Shi Xiao-dong Fan Department of Thoracic Surgery Cixi Hospital Affiliated to Wenzhou Medical College Department of Surgery Cixi Hospital Affiliated to Wenzhou Medical College

Objective:To study the mechanism of effect of miR-21 via Wnt/ β-catenin signaling pathway in human A549 lung cancer cells and Lewis lung carcinoma in ***:The effect of miR-21 on A549 cells were detected by MTT ***-21 expression levels were overexpressed or inhibited in A549 cells by transfecting with miR-21 mimics or *** among key molecules(Wnt1,β-***1 and miR-21) of mRNA and protein levels in Wnt/β-catenin signaling pathway were studied by Real-time PCR and Western blot hybridization *** ability of A549 cells was determined via Transwell chamber cell invasion assay;the role of miR-21 in A549 cells was explored via the Wnt/β-catenin signaling pathway.A Lewis lung carcinoma animal model was established to detect miR-21 expressions in tumor animals and controlled animal tissues,and verify expression changes of the above moleculesin the Wnt / β-catenin signaling pathway was determined in the animal ***:MTT assay results showed that miR-21 overexpression could markedly enhance cell absorbance value;that is,miR-21 could increase the ability proliferation of A549 cells.β-catenin and CyclinD1 expression levels were significantly higher in miR-21 mimic transfected cells(Pere transfected with miR-21 mimics,cell invasion assay revealed that the perforated cells was significantly higher than the perforated cells in the control group(Pere significantly higher;and at the same ***1,β-catenin and CyclinD1 gene expression levels were significantly increased,compared to ***:In A549 human lung cancer cells and Lewis lung carcinoma in mice,key molecules β-catenin and CyclinD1 of miR-21 expressions and the Wnt/ β-c

关键词： miR-21 Lung carcinoma Wnt/β-catenin signaling pathway

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Galvanic Corrosion of Magnesium Alloy and Aluminum Alloy by Kelvin Probe

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Journal of Wuhan University of Technology(Materials Science) 2016年第1期31卷 204-210页

作者：肖葵 dong Chaofang WEI dan WU Junsheng LI Xiaogang Corrosion and Protetion Center University of Science and Technology Beijing Beijing 100083 China Society Service Center China Association for Science and Technology Beijing 100081 China Ningbo Institute of Material Technology & Engineering Chinese Academy of Sciences Ningbo 315201 China

Galvanic corrosion on samples of AZ91D magnesium alloy coupled with 2A12 aluminum alloy during neutral salt spray test was *** variations of the surface potential were measured using scanning kelvin probe（SKP）.The results showed that galvanic effect on the corrosion of AZ91D magnesium alloy is closely related to the potential difference between the anodic and cathodic *** the initial period,corrosion only occurred in a narrow area at the coupling interface because of the limited distance galvanic ***,the corrosion rate of 2A12 aluminum alloy was accelerated due to its poor stability in strong alkali environment,which was attributed to the strong alkalization caused by the corrosion of AZ91D magnesium *** the increase of the potential of 2A12 aluminum alloy as a result of the continuous covering of corrosion products,the potential difference between the two materials was enlarged,which enhanced the galvanic corrosion.

关键词： magnesium alloy aluminum alloy galvanic corrosion scanning kelvin probe salt spray test

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Encapsulation of ionic liquid, phosphotungstic acid inside the nanocages of MIL-101(Cr): Effective and reusable catalyst for efficient solvent-free oxidative desulfurization from fuel oil

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Petroleum Science 2023年第6期20卷 3865-3874页

作者： Bo-Long Jiang dong-Xu Zhang dan-dan Yuan Yan-Guang Chen Tian-Zhen Hao Hua Song Innovation Institute for Sustainable Maritime Architecture Research and Technology Qingdao University of TechnologyQingdao 266000ShandongChina Provincial Key Laboratory of Oil&Gas Chemical Technology College of Chemistry&Chemical EngineeringNortheast Petroleum UniversityDaqing 163318HeilongjingChina Hebei Jingzhi Technology Co. LTDCangzhou 061000HebeiChina

Oxidative desulfurization from fuel oil is one of the important methods for deep *** development of efficient oxidative desulfurization catalysts is crucial for improving the desulfurization *** encapsulation of phosphotungstic acid(HPW)and ionic liquid(BMImBr)inside the mesoporous cages of MIL-101(Cr)was accomplished through a combination of“bottle around ship”and“ship in bottle”*** obtained BMImPW@MIL-101(Cr)composite was characterized by XRD,FTIR,BET,SEM,XPS and ICP *** indicated that the BMImPW@MIL-101(Cr)composites with PW^(3−) loading of 23.1–50.7 wt%were obtained,demonstrating that the“bottle around ship”method is beneficial to make full use of nanocages of MIL-101(Cr)to obtain expected high loading of active PW^(3−) .The BMImPW@MIL-101(Cr)exhibits excellent reusability with no evidence of leaching of active PW^(3−) and BMIm^(+),and well-preserved structure after successive cycles of regeneration and *** significantly improved stability of BMImPW@MIL-101(Cr)as compared to HPW@MIL-101(Cr)is possibly because the leaching of the active PW^(3−) −sites can be greatly suppressed by forming large size of BMImPW owing to introduction of BMIm^(+)*** BMImPW@MIL-101(Cr)exhibited excellent catalytic activity for solvent free oxidative desulfurization of refractory *** enhanced oxidative desulfurization activity as compared to HPW@MIL-101(Cr)can be explained by the intimate contact of sulfides with active PW^(3−) sites owing the strong attraction of BMIm^(+)cation with the sulfides.

关键词： Metal organic frameworks Phosphotungstic acid lonic liquids Stability Oxidative desulfurization

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Characterization of Fe_3Si-based coatings on low silicon steel by pulsed Nd:YAG laser cladding

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International Journal of Minerals,Metallurgy and Materials 2009年第2期16卷 208-214页

作者： dan-yang dong Chang-sheng Liu Sui-yuan Chen Bin Zhang Key Laboratory for Anisotropy and Texture of Materials of the Ministry of Education of China Northeastern University Shenyang 110004 China School of Science College Northeastern University Shenyang 110004 China

The Fe3Si based coating was produced on the Fe-1 Si steel surface by a pulsed Nd：YAG （yttrium aluminum garnet） laser. Its phase constitution and microstructure were characterized by using X-ray diffraction （XRD）, optical microscope （OM）, and field emission scanning electron microscope （FESEM） with associated energy dispersive spectroscopy （EDS） and transmission electron microscopy （TEM）. The hyperfine structure of the coating was studied by Mrssbauer spectra （MS） and the magnetic property was also measured at room temperature by a vibrating sample magnetometer （VSM）. The obtained coating is pore and crack-free with dense microstructure and high Si content. The metallurgical bonding between the coating and the substrate was realized. The microstructure of the coating is typical fine dendrites. The major phase was confirmed by XRD and TEM to be the ordering D03 structured Fe3Si phase. In addition, there were smaller amounts of the Fe5Si3 phase and the γ-Fe phase in the coating. Compared with the substrate, the laser cladding coating has a lower saturation magnetization and a higher coercive force. The poor magnetic property might be because of rapid solidification microstructure and phase constitution in the coating.

关键词： silicon steel laser cladding hyperfine structure magnetic property

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Domination Number in Graphs with Minimum Degree Two

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Acta Mathematica Sinica,English Series 2009年第8期25卷 1253-1268页

作者： er Fang SHAN Moo Young SOHN Xu dong YUAN Michael A. HENNING Department of Mathematics Shanghai University Shanghai 200444 P. R. China Department of Applied Mathematics Changwon National University 641-773 Changwon Korea Department of Mathematics Guangxi Normal University Guilin 541004 P. R. China School of Mathematical Sciences University of KwaZulu-Natal Pietermaritzburg 3209 South Africa

A set D of vertices of a graph G = （V, E） is called a dominating set if every vertex of V not in D is adjacent to a vertex of D. In 1996, Reed proved that every graph of order n with minimum degree at least 3 has a dominating set of cardinality at most 3n/8. In this paper we generalize Reed＇s result. We show that every graph G of order n with minimum degree at least 2 has a dominating set of cardinality at most （3n ＋IV21）/8, where V2 denotes the set of vertices of degree 2 in G. As an application of the above result, we show that for k ≥ 1, the k-restricted domination number rk （G, γ） ≤ （3n＋5k）/8 for all graphs of order n with minimum degree at least 3.

关键词： graph dominating set domination number restricted domination number

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Relationship between Thermodynamic Parameters for Mn-Fe Melt and Temperature

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Journal of Iron and Steel Research International 2004年第3期11卷 5-10页

作者： CHEN er-bao dong Yuan-chi GUO Shang-xing WU Bao-guo Anhui University of Technology

The carbon solubility in Mn-Fe melts were measured at 1350℃,1375℃,1425℃and 1450 ℃,and accordingly the calculated equations were *** thermodynamic derivation and calculation,some relationships between thermodynamic... 详细信息

关键词： Mn-Fe melt thermodynamic parameter temperature activity interaction coefficient

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