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Peristaltic flow of a heated Jeffrey fluid inside an elliptic duct:streamline analysis

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Applied Mathematics and Mechanics(English Edition) 2021年第4期42卷 583-592页

作者： s.NADEEM s.AKHTAR A.sALEEM Department of Mathematics Quaid-i-Azam University 45320Islamabad 44000Pakistan Department of Anatomy School of DentistryShaheed Zulfiqar Ali Bhutto Medical UniversityIslamabad 44000Pakistan

The peristaltic flow of a heated Jeffrey fluid inside a duct with an elliptic cross-section is studied.A thorough heat transfer mechanism is interpreted by analyzing the viscous effects in the energy *** governing mathematical equations give dimensionless partial differential equations after *** final simplified form of the mathematical equations is evaluated with respect to the relevant boundary conditions,and the exact solution is *** results are further illustrated by graphs,and the distinct aspects of peristaltic flow phenomena are discussed.

关键词： peristalsis elliptic duct Jeffrey fluid streamline

Effect of Dy-substitution on structural and magnetic properties of Mn-Zn ferrite nanoparticles

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Journal of Rare Earths 2018年第1期36卷 86-94页

作者： K.V.Zipare s.s.Bandgar G.s.shahane Department of Electronics DBF Dayanand College of Arts and Science

This paper describes the structural and magnetic properties of Dy-substituted Mn-Zn ferrite nano- particles. Mn-Zn-Dy ferrite nanopafficles of the composition ***204 （x- 0.05, 0.1, 0.15 and 0.2） were synthesized by a facile chemical co-precipitation method. The samples were characterized through X-ray diffraction （XRD）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, vibrating sample magnetometer （VsM） and Curie temperature. The XRD patterns confirm the synthesis of single crystalline phase of Mn-Zn-Dy ferrite nanoparticles. Lattice parameter increases with increase in Dy-substitution which confirms the replacement of Fe3＋ ions by Dy3＋ ions. Crystallite size is of the order of 6-8 nm for all these samples. The particle sizes observed from TEM analysis are in good agreement with the XRD values. The magnetic measurements show super- paramagnetic nature of the samples. The saturation magnetization decreases with increase in Dy- concentration and can be correlated to modifications in the A-B exchange interactions as a result of the structural modifications due to Dy-substitution. The Curie temperature for ***204 nano- particles is 124 ℃ and decreases up to 84 ℃with the increase in the Dy-concentration. The decrease in Curie temperature can be attributed to the weakening of the superexchange interaction between A-site and B-site as a result of Dy-substitution. The low value of Curie temperature and higher value of ther- momagnetic coefficient kT shown by these samples makes them suitable for the preparation of tem- perature sensitive ferrofiuid for heat transfer applications.

关键词： Mn-Zn-Dy ferritesstructural characterizationMagnetic propertiesCurie temperatureRare earths

Effect of Eu^(3+),Bi^(3+),and Li^(+) doping on luminescent property of GdNbO_(4)

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Journal of Rare Earths 2024年第1期42卷 66-75,I0003页

作者： s.W.Wi Y.s.Lee Department of Physics and Integrative Institute of Basic sciences Soongsil UniversitySeoul06978Republic of Korea

We investigated the emission properties of Eu^(3+)-doped GdNbO_(4)-based oxide phosphors,aiming at improving the Eu^(3+)emission by codoping of Bi^(3+)and Li^(+).Eu^(3+)singly doped,Eu^(3+)and Bi^(3+)doubly doped,and Eu^(3+),Bi^(3+),and Li^(+)triply doped GdNbO_(4)were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu^(3+)in the singly doped samples are significantly improved by the codoping of Bi^(3+),mainly due to the energy transfer from Bi^(3+)to Eu^(3+).The additional codoping of Li^(+)is found to increase the Eu^(3+)emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu^(3+)in GdNbO_(4)does not change significantly with the codoping of Bi^(3+)and Li^(+).Our results indicate that Li^(+)doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO_(4)phosphors.

关键词： Eu^(3+) GdNbO_(4) Codoping of Li^(+) Photoluminescence sensitizer Rare earths

Nonrelativistic shannon information entropy for Kratzer potential

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Chinese Physics B 2016年第4期25卷 37-41页

作者： Najafizade s A Hassanabadi H Zarrinkamar s Physics Department University of Shahrood Department of Basic sciences Garmsar Branch Islamic Azad University

The shannon information entropy is investigated within the nonrelativistic framework. The Kratzer potential is con- sidered as the interaction and the problem is solved in a quasi-exact analytical manner to discuss the ground and first excited states. some interesting features of the information entropy densities as well as the probability densities are demonstrated. The Bialynicki-Birula-Mycielski inequality is also tested and found to hold for these cases.

关键词： schrOdinger equation Kratzer potential shannon entropy

synthesis of Flower-Like Nanoparticles of Anatase Titania by Microwave solvo-Hydrothermal Method

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Acta Metallurgica sinica(English Letters) 2013年第6期26卷 742-746页

作者： s.Mahmoudi s.Boudjadar Ceramics Laboratory Department of PhysicsUniversity of Constantine

Anatase titania nanoparticles with an average size of about 14 nm were synthesized by microwave solvothermal method from TiCI4 and ethanol as a precursor and solvent respectively. The shapes of as prepared samples were modified by microwave hydrothermal treatment in strongly alkaline medium at 100℃ for 2 h, the agglomerate particles can be converted to the nanorods then to flower-like sphere. The structure, morphology and optical properties of as-prepared powders were investigated by X-ray diffraction, scanning electron microscopy and UV- vis absorption spectroscopy, the quality of the samples was examined by IR absorption spectroscopy and room temperature photoluminescence （PL）. The results showed that the synthesized Ti02 revealed the formation of the nanorods and the flower-like shape of titania after post treatment in 5 mol/L and 10 mol/L NaOH solution, respectively. IR absorption spectra showed that the as-prepared TiO2 nanocrystals were highly pure and strongly surface hydrated, The photoluminescence measurement showed that five main emission peaks appeared in UV, violet, blue and green regions.

关键词： Titanium dioxide Microwave hydrothermal Alkaline medium Flower-like Photoluminescence

Investigation of the Effect of Using Different Fly Ash on the Mechanical Properties in Cemented Paste Backfill

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Journal of Wuhan University of Technology(Materials science) 2022年第4期37卷 620-627页

作者： Tuylu s Department of Mining Engineering Istanbul University-CerrahpasaIstanbul34500Turkey

In the cemented paste backfill(CPB)method,which can also be used for fortification purposes in mines,different additive materials with pozzolanic properties can be employed as substitutes instead of cement that is the main *** of the most popular pozzolanic materials that can be employed instead of cement is fly ash,which is thermal power plant *** the compositions of fly ash and tailings used in high amounts in the CPB method,as well as the chemical structures that these materials form by interacting with the cement binder,affect the mechanical properties of the material depending on *** this study,fly ash with 4 different chemical compositions(TFA,sFA,YFA,and CFA)was used as a cement substitute in *** substituting fly ash with different chemical compositions in different proportions,CPB samples were created and their strength was elucidated according to 28,56,and 90-day curing *** results of the study revealed that TFA with the highest CaO/siO_(2) and sO_(3) ratios remained stable at the strength values of 6 MPa(total 9% binder)and 10 MPa(total 11% binder)in the long ***,CFA with the lowest CaO/siO_(2),sO_(3),and the highest siO_(2)+Al_(2)O_(3)+Fe_(2)O_(3) ratios resulted in the greatest strength increase at a 20%substitution rate(11% of the total binder).Nevertheless,it was found that the sFA,which is in Class F,increased its strength in the early period based on the CaO rate.

关键词： tailings disposal cemented paste backfill fly ash chemical properties strength

seasonal variations of rotifers from a high altitude urban shallow water body, La Cantera Oriente (Mexico City, Mexico)

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Chinese Journal of Oceanology and Limnology 2017年第6期35卷 1387-1397页

作者： sergio González GUTIERREZ s.s.s. sARMA s. NANDINI Postgraduate Programme in Marine sciences and Limnology National Autonomous University of Mexico Circuito Exterior sin Ciudad Universitaria Mexico City 04510 Mexico Laboratory of Aquatic Zoology Division of Research & Postgraduate Studies National Autonomous University of Mexico Campus Iztacala Av. de los Barrios No.1 AP 314 Los Reyes Tlalnepantla State of Mexico 54090 Mexico

La Cantera Oriente is a shallow freshwater volcanic water body located at an altitude of 2 270 m above sea level in the Ecological Reserve of san Angel Pedregal of Mexico City （Mexico）. In order to ensure the conservation of its biological heritage including zooplankton, the present work was undertaken to quantify the seasonal changes in the diversity and density of rotifers and the selected physico- chemical variables during 2013-2014. Qualitative analysis of the zooplankton samples yielded 68 rotifer species which represented 24 genera in 15 families. Brachionus calyciflorus Pallas, 1766, B. quadridentatus Hermann, 1783, Polyarthra vulgaris Carlin, 1943, Lecane closterocerca （schmarda, 1859） and Keratella cochlearis （Gosse, 1851） were the most common species. Preston plots of species frequency-density revealed that as many as 30% of the rotifer taxa were dominant throughout the year. The species with high population densities were Brachionus quadridentatus, Lecane closterocerca, Keratella cochlearis, and Lepadellapatella; their peak densities were 2 000, 1 000, 180 and 90 ind./L, all occurring in summer. Canonical correspondence analysis showed that Platyias quadricornis was related to the concentration of phosphates available in the environment and the conductivity, while B. quadridentatus was positively correlated with chlorophyll-a. The trophic status of the lake was eutrophic based on Chl-a content but oligotrophic with relation to the Braehionus： Trichocerca ratio.

关键词： high altitude zooplankton seasonal density dynamics limnology rotifera

Plant Communities and Factors Responsible for Vegetation Pattern in an Alpine Area of the Northwestern Himalaya

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Journal of Mountain science 2011年第6期8卷 817-826页

作者： Man s.RANA s.s.sAMANT Y.s.RAWAT Department of Plant science Government Degree College G.B.Pant Institute of Himalayan Environment & Development Department of Botany D.S.B.CampusKumaun University

The study intended to describe the alpine vegetation of a protected area of the northwestern Himalaya and identify the important environmental variables responsible for species *** placed random plots covering different habitats and altitude to record species composition and environmental *** was classified using hierarchical cluster analysis and vegetation-environment relationships were evaluated with Canonical Correspondence *** communities,each in alpine shrub and meadows were delineated and well justified in the ordination *** species for the different communities were *** species richness and diversity were found in community IV among shrub communities and community II among the *** environmental variables explained 61.5% variation in shrub vegetation and 59.8% variation in *** variables explained higher variability (～35%) than spatial variables (～21%) in both shrubs and ***,among the spatial variables and carbon/nitrogen ratio and nitrogen among the soil variables explained maximum *** 40% variations left *** and species diversity among the other variables had significant correlation with ordination *** showed that altitude and C/N ratio played a significant role in species *** sampling efforts and inclusion of other non-studied variables are also suggested for better understanding.

关键词： species diversity Indicator species Environmental variable Ordination Explainedvariation

Micro-synchrophasor based special protection scheme for distribution system automation in a smart city

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Protection and Control of Modern Power systems 2020年第1期5卷 97-110页

作者： Deepa s.Kumar savier J.s Biju s.s Dept of Electrical Engineering College of EngineeringTrivandrumKeralaIndia 400/220kV substation Powergrid Corporation of India Ltd.TrivandrumKeralaIndia Power system Operations Kerala State Electricity Board Ltd.KeralaIndia

Introduction:Aspects of power system protection which contributes to mal-operations and blackouts can be improved by supervision of system behavior and response based analysis rather than condition-based or event-based analysis using wide area measurements based on synchrophasor *** paper explores the application of micro-Phasor Measurement Unit for time synchronized real-time distribution network monitoring and agile decision support schemes for system prognosis and *** description:The scheme is proposed as part of a project on“Power system Voltage stability Analysis using synchrophasors in Distribution system of Kerala Grid”at Kerala state Electricity Board *** actual grid occurrence during the severe tropical cyclone Ockhi,is considered as the base case which motivated the *** and evaluation:A voltage stability index(VsI)based special protection scheme(sPs)for radial distribution network at a proposed smart city is presented in the present *** proposed special protection scheme on actual implementation can use data from proposed local micro-Phasor Measurement *** PMU is proposed to be placed at one of the key nodes of the distribution system network in the ***:The VsI is derived using local phasor values and is used to initiate a special Protection scheme for N-1 contingency at the key node,so as to ensure availability of the most essential feeder which provides supply to a hospital campus housing several health institutes of prime *** voltage stability index derived is tested and sPs is validated using real-time grid data.

关键词： Micro-phasor measurement unit Power system protection Voltage stability Power system stability Power distribution smart grids