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Photometric and Spectroscopic Study of Ten Low Mass Ratio Contact Binary Systems:Orbital Stability,O'Connell Effect and Infrared Calcium Line Filling

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Research in Astronomy and Astrophysics 2024年第8期24卷 212-222页

作者： Surjit S.Wadhwa Adam Popowicz Raúl Michel Petar Kostić Oliver Vince Nick F.H.Tothill ain y.de horta Miroslav D.Filipović School of Science Western Sydney UniversityLocked Bag 1797PenrithNSW 2751Australia department of Electronics Electrical Engineering and MicroelectronicsSilesian University of TechnologyAkademicka 1644120 GliwicePoland Instituto de Astronomía UNAM.A.P.87722800 EnsenadaBCMéxico Astronomical Observatory Volgina 711060 BelgradeSerbia

Low mass ratio contact binary systems are more likely to have unstable orbits and potentially *** addition,such systems exhibit characteristics such as starspots and high energy emissions(UV)suggestive of chromospheric and magnetic *** curve modeling of ten contact binary systems is *** were found to be of extreme low mass ratio ranging from 0.122 to 0.24 and three were found to be potentially unstable and possible merger *** of the infrared calcium absorption lines is a marker of increased chromospheric *** use the available Large Sky Area Multi-Object Fiber Spectroscopic Telescope spectra along with matched standard spectra(broadened for rotation)to measure the excess filling of the central core depression flux of the two main infrared calcium absorption linesλ8542 andλ*** find that all reported contact binaries have excess filling of the core flux in the infrared calcium *** of the systems reported were also observed by the Galaxy Evolution Explorer mission and we find that all three have features of excess ultraviolet emissions further adding evidence for increased chromospheric activity in low mass ratio contact *** of both orbital stability and absorption line filling is dependent on the determination of geometric and absolute parameters from light curve *** an insignificant number of contact binary light curves exhibit the O’Connell effect,usually attributed to *** discuss the inclusion of starspots in light curve solutions and how they influence the geometric and absolute parameters.

关键词： (stars)binaries eclipsing-techniques photometric-stars chromospheres

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Photometric analysis of two extreme low mass ratio contact binary systems

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Research in Astronomy and Astrophysics 2021年第9期21卷 217-223页

作者： Surjit S.Wadhwa Nick F.H.Tothill ain y.de horta Miroslav Filipovié School of Science Western Sydney UniversityLocked Bag 1797PenrithNSW 2751Australia

Multi-band photometry and light curve analysis for two newly recognized contact binary systems,TyC 6995-813-1 and NSVS 13602901,are *** were found to be of extreme low mass ratios 0.11 and 0.17,*** secondary components of both systems show evidence of considerable evolution with elevated densities as well as both luminosity and radii well above their main sequence *** in the absence of significant spot activity,at least one of the systems,TyC 6995-813-1,displays features of magnetic and chromospheric *** 6995-813-1 is also determined to be a potential merger candidate with its current separation near the theoretical instability separation.

关键词： stars:binaries:eclipsing stars:evolution stars:low-mass techniques:photometric

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Photometric and Spectroscopic Study of Two Low Mass Ratio Contact Binary Systems:CRTS J225828.7-121122 and CRTSJ030053.5+230139

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Research in Astronomy and Astrophysics 2023年第11期23卷 1-6页

作者： Surjit S.Wadhwa Jelena Petrović Nick F.H.Tothill ain y.de horta Miroslav D.Filipović Gojko Djurašević School of Science Western Sydney UniversityLocked Bag 1797PenrithNSW 2751Australia Astronomical Observatory Volgina 711060 BelgradeSerbia

The study reports photometric and spectroscopic observations of two recently recognized contact binary *** systems show total eclipses and analysis of the light curves indicates both have very low mass ratios of less than *** derive absolute parameters from color and distance based calibrations and show that,although both have low mass ratios,they are likely to be in a stable orbit and unlikely to *** other respects,both systems have characteristics similar to other contact binaries with the secondary larger and brighter than their main sequence counterparts and we also find that the secondary is considerably.denser than the primary in both systems.

关键词： (stars:)binaries:eclipsing stars:mass-loss techniques:photometric

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Dynamical study of varicella-zoster virus model in sense of Mittag-Leffler kernel

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International Journal of Biomathematics 2024年第3期17卷 153-183页

作者： Qura Tul ain Aziz Khan Thabet Abdeljawad J.F.Gomez-Aguilar Saleem Riaz department of Mathematics Guizhou University GuiyangGuizhou 550025P.R.China department of Mathematics and Sciences Prince Sultan University P.O.Bor 66833 11586 RiyadhSaudi Arabia department of Medical Research China Medical University Taichung 40402Taiwan CONACyT-Tecnologico Nacional de Mécico/CENIdeT Interior Internado Palmira S/N Col.Palmira C.P.62490CuernavacaMorelosMécico IConsejo Academico Universidad Virtual CNCIMonterreyMécico School of Automation Northwestern Polytechnical University 170072 Xian P.R.China

The primary varicella-zoster virus(VzV)infection that causes chickenpox(also known as varicella),spreads quickly among people and,in severe circumstances,can cause to fever and *** this paper,the Mittag-Leffler fractional operator is used to examine the mathematical representation of the *** fractional-order differential equations are created in terms of the disease's dynamical analysis such as S:Susceptible,V:Vaccinated,E:Exposed,I:Infectious and R:*** derive the existence criterion,positive solution,Hyers-Ulam stability,and boundedness of results in order to examine the suggested fractional-order model's ***,some numerical examples for the VzV model of various fractional orders are shown with the aid of the generalized Adams-Bashforth-Moulton approach to show the viability of the obtained results.

关键词： Varicella-zoster virus model Hyers-Ulam stability ABC fractional operator Schauder fix point theory numerical analysis

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Photometric Analysis of Three Potential Red Nova Progenitors

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Research in Astronomy and Astrophysics 2022年第10期22卷 103-110页

作者： Surjit S.Wadhwa ain de horta Miroslav D.Filipovic N.F.H.Tothill Bojan Arbutina Jelena Petrovic Gojko Djurasevic School of Science Western Sydney UniversityLocked Bag 1797PenrithNSW 2751Australia department of Astronomy Faculty of MathematicsUniversity of BelgradeStudentski trg 1611000 BelgradeSerbia Astronomical Observatory Volgina 711060 BelgradeSerbia

We present photometric analysis of three bright red nova progenitor contact binary systems:ASAS J082151-0612.6,TyC 7281-269-1 and TyC *** primary components in all three systems are solar-type low mass stars with radii somewhat larger than their zero age main sequence *** secondaries,as in most contact binary systems,have radii and luminosities well above their main sequence *** three have extremely low mass ratios ranging from 0.075 to 0.097 and two have high degrees of contact,in excess of 75%.All three have mass ratios and separations below the theoretical values for orbital *** activity,a hallmark of magnetic activity and magnetic braking,considered important in mediating angular momentum loss,is also *** three systems demonstrate the O’Connell effect,and all systems require the introduction of star spots for a better light curve *** addition,we show that ASAS J082151-0612.6 and TyC 7281-269-1 have a UV color excess in the range indicating high chromospheric *** measure of potential significant magnetic activity is X-ray luminosity;TyC 7275-1968-1 and probably also TyC 7281-269-1 have X-ray luminosity well above other contact binary *** conclude that it is likely that all three are unstable and hence are potential merger candidates.

关键词： (stars:)binaries eclipsing-techniques photometric-stars low-mass

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Low-density Microplastics in Recreational Parks of Al ain, United Arab Emirates: Abundance, Composition, and Potential Effects on Soil Health

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Journal of Environmental Protection 2024年第2期15卷 109-123页

作者： Rener de Jesus Ahmed Abuibaid Bassam Al-Hindawi Ruwaya AlKendi department of Biology College of Science United Arab Emirates University Al Ain UAE department of Chemistry College of Science United Arab Emirates University Al Ain UAE

Microplastics (MPs) have been an emerging concern due to their harmful effects on the ecosystem and are ubiquitous in various habitats, from marine to terrestrial environments. However, studies on the presence of MPs in recreational areas are limited. One of the previous works has reported that urban recreational parks are considered “sinks” for plastic debris, including MPs. In this study, low-density MPs (LD-MPs) in soil samples collected from recreational parks of Al ain, United Arab Emirates (UAE) were isolated by.density flotation method. Results showed that these parks have varying levels of LD-MPs caused by various anthropogenic activities, such as sludge use and application of reclaimed water from wastewater treatment facilities in those areas. These plastic particles were isolated in 87% of the soil samples, with an average concentration of 1550 ± 340 MPs/kg. Predominantly, these comprised large LD-MPs (300 - 5000 μm), with red and blue being the most common colors. Fourier transform infrared (FTIR) spectroscopy identified possible synthetic polymers, including polyethylene and polypropylene. Additionally, a negative correlation was observed between LD-MP concentration and soil pH and moisture content, indicating potential adverse effects on soil health. These findings highlight the need for monitoring and managing microplastic pollution in urban recreational areas to mitigate its ecological impacts.

关键词： Plastic Particles FTIR Analysis Microfibers Soil Pollutants Urban Parks

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The Association between Researchers’Conceptions of Research and Their Strategic Research Agendas

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Journal of Data and Information Science 2020年第4期5卷 56-74页

作者： João M.Santos Hugo horta Instituto Universitário de Lisboa(ISCTE-IUL) Centro de Investigação e Intervenção Social(CIS-IUL)LisbonPortugal Social Contexts and Policies of Education Faculty of EducationThe University of Hong KongHong Kong SARChina

Purpose:In studies of the research process,the association between how researchers conceptualize research and their strategic research agendas has been largely *** study aims to address this ***/methodology/approach:This study analyzes this relationship using a dataset of more than 8,500 researchers across all scientific fields and the *** studies the associations between the dimensions of two inventories:the Conceptions of Research Inventory(CoRI)and the Multi-Dimensional Research Agenda Inventory—Revised(MDRAI-R).Findings:The findings show a relatively strong association between researchers’conceptions of research and their research *** all conceptions of research are positively related to scientific ambition,the findings are mixed regarding how the dimensions of the two inventories relate to one another,which is significant for those seeking to understand the knowledge production process *** limitations:The study relies on self-reported data,which always carries a risk of response *** implications:The findings provide a greater understanding of the inner workings of knowledge processes and indicate that the two inventories,whether used individually or in combination,may provide complementary analytical perspectives to research performance *** may thus offer important insights for managers of research environments regarding how to assess the research culture,beliefs,and conceptualizations of individual researchers and research teams when designing strategies to promote specific institutional research focuses and ***/value:To the best of the authors’knowledge,this is the first study to associate research agendas and conceptions of *** is based on a large sample of researchers working worldwide and in all fields of knowledge,which ensures that the findings have a reasonable degree of generalizability to the global population of researchers.

关键词： Conception of research Research agendas Researchers’beliefs Research strategy Views of research Research processes

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Co取代的六铁酸盐在N_2O催化分解反应中的应用(英文)

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催化学报 2013年第7期34卷 1357-1362页

作者： Barkat Ul-ain Safeer AHMED 黄延强中国科学院大连化学物理研究所催化基础国家重点实验室辽宁大连116023 伊斯兰堡奎德-i-阿扎姆大学化学系巴基斯坦伊斯兰堡45320

采用溶胶-凝胶法制备了Co取代的Ba2Mg2-xCoxFe12O22（x=0.0-2.0）催化剂,并考察了其在高浓度N2O（30vol%）分解反应中的催化活性.结果表明,Co的取代显著提高了Ba2Mg2Fe12O22催化剂活性,当x=2时,N2O的完全分解温度从1123K降至973K;提高... 详细信息

采用溶胶-凝胶法制备了Co取代的Ba2Mg2-xCoxFe12O22（x=0.0-2.0）催化剂,并考察了其在高浓度N2O（30vol%）分解反应中的催化活性.结果表明,Co的取代显著提高了Ba2Mg2Fe12O22催化剂活性,当x=2时,N2O的完全分解温度从1123K降至973K;提高催化剂焙烧温度会导致其表面积降低,进而降低其催化活性;但采用微波加热则能显著提高催化剂活性.

关键词：一氧化二氮分解六铁酸盐 Ba2Mg2Fe12O22 钴微波

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Synthesis and comparative study of reactivities of δ-lactone,estor group and oxazinone ring in coumarin derivatives towards carbon or nitrogen nucleophiles

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Chinese Journal of Chemistry 1990年第5期8卷 469-473页

作者： EL-KAFRAWy,A.F. SOLIMAN,A.y. BAKER,H.M. MOHAMED,F.K. EL-KADy,M.y.department of Chemistry,Faculty of Science,ain Shams University and Faculty of Education at El-Fayoum,Cairo.Egypt department of Chemistry Faculty of Science Ain Shams University and Faculty of Education at El‐Fayoum Cairo Egypt

Condensation of methyl 7-methylcoumarin-4-acetate(2)with primary amines and with an- thranilic acid gave 7-methyl-2-oxo-N-aryl-2H-[1]-benzopyran-4--acetamide(4a—d)and(7),respectively. Compound 7 underwent cyclization to give 2-(7-methyl-2-oxo-2H-[1]-benzopyran-4-yl)-methyl-4H-3,1- benzoxazin-4-one(3).The reaction of 3 with aromatic amines gave the corresponding quinazolone derivatives 5 which tautomerises to the thermodynamically more stable isomer 6,whereas its reaction with Grignard reagents and aromatic aldehydes gave 8a,8b,and 9a,9b,respectively.

关键词： Synthesis and comparative study of reactivities of lactone,estor group and oxazinone ring in coumarin derivatives towards carbon or nitrogen nucleophiles ring

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Heterocyclic compounds from 3-(4-phenyl) benzoyl propionic acid

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Chinese Journal of Chemistry 1996年第6期14卷 532-540页

作者： SOLIMAN, A.y. BAKEER, H.M. ATTIA, LA.Science department, Faculty of Teachers, P.O.Box 2313, Alhasa 31982, Saudi Arabia Chemistry.department, Faculty of Science, Fayoum, Cairo University, EgyptFaculty of Engineering, ain Shames University, Egypt Science department Faculty of Teachers P.O. Box 2313 Alhasa 31982 Saudi Arabia Chemistry.department Faculty of Science Fayoum Cairo University Egypt Faculty of Engineering Ain Shames University Egypt

3-(4-Phenyl) benzoyl propionic acid was used as the starting material for the synthesisof furanones (2), pyrrolinones (5), pyridazinones (7), benzoxazinones (8) and quinazolinones (9-11). The behaviour of the derivati... 详细信息

关键词： Substituted benzoyl propionic acid heterocyclic compounds synthesis

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