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pedogenically degenerated illite and chlorite lattices aid to palaeoclimatic reconstruction for chronologically constrained(8-130 ka) loess-palaeosols of Dilpur Formation,Kashmir,India

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Geoscience Frontiers 2020年第4期11卷 1353-1367页

作者： Meenakshi J.p.Shrivastava Rakesh chandra Department of Geology University of DelhiDelhi110007India Department of Earth Sciences University of KashmirJammu and Kashmir190006India

Chronologically well-constrained loess-palaeosols(recorded glacial and inter-glacial climate) revealed pedogenesis induced ionic substitutions,caused end-member compositional deviations in illite and chlorite,linked to widespread climatic changes occurred during Late ***,micro-level climatic resolution is yet to be ***,layer-wise X-ray diffraction analyses of clay separates,followed by Rietveld refinement revealed varied cell parameters and interatomic *** values for detrital and pedogenic illite and chlorite when plotted against stratigraphic succession show notable changes in the crystallographic *** illite lattices associated with inadequately pedogenized palaeosols have been altered into illite/smectite mixed layers,but,the chlorite lattices represent expansion of a-,b-and contraction of c-axes with much greater amount of distortions,suggestive of warm-humid and acidic *** detrital 48,44 and 83,74 bonded illite and chlorite with2 sub-types each,when pedogenized retained 48,44 and 34;and 83 and 74 bonds(in their neo-formed 3 and 2 sub-types),*** Al-O bond shows expansion,but,unchanged Si-O and decreased Si-K and K-O bonds show loss of Al and retention of Si and K ions in the illite *** illite with 32 atoms and 48 bonds represent contraction of K-O,Si-K,Al-O and Si-O bonds caused bond reinforcement;however,loss of Al3+reflects all-out illite *** to Al-O and K-O bond expansion,major K+ and Al3+ ionic loss occurred during the LGM,however,further ionic loss depends upon the magnitude of the loess-palaeosol weathering that they have *** clilate sensitive Fe,Mg and Al ionic losses for Fe-O,Mg-O and Al11-O9 bond length expansions were recognized in the chlorite *** ionic losses are common,but,complete distortion is attributed to Al,Si,Fe and Mg ionic losses,followed by weakening of Al-O,Si-O,Fe-O and Mg-O ***,Si-O4 and Fe1-O4 bonds,and Si and Fe1 st i

关键词： Crystallographic defects Cell parameters Inter-atomic distances Glacial-interglacial periods Rietveld refinement LGM

A comparative analysis of unsteady and steady Buongiorno’s Williamson nanoliquid flow over a wedge with slip effects

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Chinese Journal of Chemical Engineering 2020年第7期28卷 1767-1777页

作者： R.chandra Sekhar Reddy p.Sudarsana Reddy Department of Mathematics Rajeev Gandhi Memorial Collge of Engineering&TechnologyNandyalA.P.India

Comparison between unsteady and steady MHD Buongiorno’s model Williamson nanoliquid flow through a wedge with slip effects,chemical reaction and radiation is made in this *** and Brownian motion are also considered in this *** similarity variables are presented to transmute the governing pDEs into the set of non-linear *** most widely authenticated finite element method is implemented to analyze these set of ODEs *** behavior of concentration,temperature and velocity sketches for varied values of relevant parameters is numerically calculated and the outcomes are plotted through *** numerical values of dimensionless rates of mass transfer,heat and velocity are also evaluated and depicted through *** is noted that with upsurging values of angle of wedge parameter,the distributions of temperature of the liquid intensify in both steady and unsteady cases.

关键词： Finite element method Chemical reaction Williamson nanoliquid Thermophoresis Thermal radiation Brownian motion

Oxygen Fugacity and Water Activity during Thermal peak and Retrogression of Granulites around the Sarvapuram Area, Karimnagar Granulite Terrane, Andhra pradesh, India

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Acta Geologica Sinica(English Edition) 2019年第6期93卷 1900-1908页

作者： p.chandra SINGH D.pRAKASH Department of Earth Sciences Indian Institute of TechnologyPowaiMumbai400076India Centre of Advanced Study in Geology Banaras Hindu UniversityVaranasi221005India

The investigated area around Sarvapuram represents a part of the Karimnagar granulite terrane of the Eastern Dharwar Craton, India. Garnet–bearing gneiss is hosted as enclaves, pods within granite gneiss and charnockite. It is largely made up of garnet, orthopyroxene, cordierite, biotite, plagioclase, K–feldspar, sillimanite and quartz. The peak metamorphic stage is represented by the equilibrium mineral assemblage i.e. garnet, orthopyroxene, cordierite, biotite, plagioclase, sillimanite and quartz. Breakdown of the garnet as well as preservation of the orthopyroxene–cordierite symplectite, formation of cordierite with the consumption of the garnet + sillimanite + quartz represents the decompressional event. The thermobarometric calculations suggest a retrograde p–T path with a substantial decompression of c. 3.0 kbar. The water activity(XH2 O) conditions obtained with the win TWQ program for core and symplectite compositions from garnet–bearing gneiss are 0.07–0.14 and 0.11–0.16 respectively. The quantitative estimation of oxygen fugacity in garnet–bearing gneiss reveal log f O2 values ranging from-11.38 to-14.05. This high oxidation state could be one of the reasons that account for the absence of graphite in these rocks.

关键词： metamorphic conditions oxygen fugacity water activity garnet–bearing gneisses Karimnagar granulite terrane India

TENSOR SUM AND DYNAMICAL SYSTEMS

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Acta Mathematica Scientia 2014年第6期34卷 1935-1946页

作者： D.SENTHILKUMAR p.chandra KALA Department of Mathematics Government Arts College(Autonomous)Coimbatore-641 018India

In this paper we introduce the concept of tensor sum semigroups. Also we have given the examples of tensor sum operators which induce dynamical system on weighted locally convex function spaces.

关键词： tensor sum composition operators multiplication operator dynamical systems seminorm operator valued mapping

Ion Conduction in Superionic Glassy Electrolytes:An Overview

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Journal of Materials Science & Technology 2013年第3期29卷 193-208页

作者： Angesh chandra Alok Bhatt Archana chandra Department of Applied physics Shri Shankaracharya Institute of Prof.Manag.& Tech.Raipur 492015C.G.India Department of Applied physics M.P Christian College of Engg.& Tech.Bhilai 490026C.G.India

The various theoretical and experimental models for ion conduction mechanism of fast ion conducting （FIC） glass electrolytes have been reported in the present review paper. Some characterization techniques of FIC glasses are presented. The experimental methods for determination of some ion transport parameters viz ionic conductivity （σ）, ionic mobility （μ）, mobile ion concentration （n）, ionic drift velocity （Vd）, ionic transference number （tion） and activation energies of FIC glasses are explained. The solid state battery fabrication by using some FIC glasses is also reported.

关键词： Ion conduction Glassy solid electrolyte Fast ion conducting (FIC) glass Superionic solid Relaxation phenomenon

AstroSat Observations of the Be/X-Ray Binary XTE J1946+274 During 2018 and 2021 Outbursts

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Research in Astronomy and Astrophysics 2023年第4期23卷 26-43页

作者： Amar Deo chandra Jayashree Roy p.C.Agrawal Indian Institute of Science Education and Research Kolkata Mohanpur 741246West BengalIndia Inter-University Center for Astronomy and Astrophysics Post Bag 4Pune 411007MaharashtraIndia Department of Astronomy and Astrophysics Tata Institute of Fundamental ResearchHomi Bhabha RoadMumbai 400005MaharashtraIndia

We present the timing and spectral studies of the Be/X-ray binary XTE J1946+274 during its 2018 and 2021 giant outbursts using observations with the SXT and LAXpC instruments on the AstroSat *** the 1998 and 2010 outbursts,where a giant outburst was followed by several low intensity periodic outbursts,the 2018 and 2021 outbursts were single *** X-ray pulsations are detected over a broad energy band covering 0.5–80 keV from the compact *** construct the spin evolution history of the pulsar over two decades and find that the pulsar spins-up during the outbursts but switches to spin-down state in the quiescent periods between the *** resolved pulse profiles generated in several bands in 0.5–80 keV show that the pulse shape varies with the *** energy spectrum of the pulsar is determined for the 2018 and 2021 *** best fit spectral models require presence of cyclotron resonant scattering feature at about 43 keV in the energy spectra of both the *** find indication of possible reversal in the correlation between the cyclotron line energy and luminosity which needs to be ascertained from future *** the best fit spectra the X-ray luminosity of XTE J1946+274 is inferred to be 2.7×10^(37) erg s^(-1) for the 2018 observations and 2.3×10^(37) erg s^(-1) for the 2021 *** discuss possible mechanisms which can drive outbursts in this transient Be X-ray binary.

关键词： accretion-accretion disks-stars neutron-(stars:)pulsars general-X-rays binaries-stars emission-line-Be-X-rays bursts

Effect of size on momentum distribution of electrons around vacancies in NiO nanoparticles

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Chinese physics B 2015年第4期24卷 296-299页

作者： Anjan Das Atis chandra Mandal p.M.G.Nambissan Department of physics A.P.C.Roy Government College Department of physics University of Burdwan Applied Nuclear physics Division Saha Institute of Nuclear Physics

Very small nickel oxide nanoparticles were prepared by a sol-gel procedure using nickel nitrate hexahydrate and ammonium hydroxide as precursors. The particles are in the range of 5 nm-11 rim. The x-ray diffraction （XRD） crystallography and high resolution transmission electron microscopy （HRTEM） were employed to characterize the samples. They were found to be polycrystalline in nature and fcc （NaCl-type） in structure, with the lattice parameter varying with annealing temperature. HRTEM pictures show that the as-prepared samples are hexagonal in shape. positron annihilation spectroscopy was used to investigate the Doppler-broadened spectra of the samples. The S and W parameters revealed that the chemical surroundings and momentum distribution of the vacancy clusters vary with crystallite size.

关键词： nanoparticles semiconductor defect cluster positron annihilation sol-gel

Electroosmotic oscillatory flow of micropolar fluid in microchannels:application to dynamics of blood flow in microfluidic devices

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Applied Mathematics and Mechanics(English Edition) 2014年第6期35卷 749-766页

作者： J.C.MISRA S.chandra G.C.SHIT p.K.KUNDU Department of Mathematics Institute of Technical Education and ResearchSiksha O Anusandhan University Department of Mathematics Jadavpur University

The electroosmotic flow of a micropolar fluid in a microchannel bounded by two parallel porous plates undergoing periodic vibration is studied. The equations for conservation of linear and angular momentums and Gauss＇s law of charge distribution are solved within the framework of the Debye-Hückel approximation. The fluid velocity and microrotation are assumed to depend linearly on the Reynolds number. The study shows that the amplitude of microrotation is highly sensitive to the changes in the magnitude of the suction velocity and the width of the microchannel. An increase in the micropolar parameter gives rise to a decrease in the amplitude of microrotation. Numerical estimates reveal that the microrotation of the suspended microelements in blood also plays an important role in controlling the electro-osmotically actuated flow dynamics in microbio-fluidic devices.

关键词： blood flow electrohydrodynamic effect microfluidics channel flow

Integrated Analysis of the Trees and Associated UnderCanopy Species in a Subalpine Forest of Western Himalaya,Uttarakhand, India

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Journal of Mountain Science 2015年第1期12卷 154-165页

作者： Vinod K.BISHT chandra p.KUNIYAL Bhagwati p.NAUTIYAL pratti prasad Herbal Research and Development Institute Department of Horticulture Aromatic and Medicinal Plants School of Earth Sciences and Natural Resources Management Mizoram University High Altitude plants physiology Research Centre HNB Garhwal (Central) University

Subalpine forests are known as outstanding habitats due to co-existence of both temperate and alpine vegetation and are classic example of ecotonal zones. Limited but diverse physiognomy of trees inhabiting in subalpine forest results in variability within under-canopy habitat conditions. Studies were undertaken to assess population status, habitat preference and interferences to the trees and associated under-canopy herbs in a subalpine forest of western Himalaya. A total of lo woody and 23 under-canopy herbs were recorded in the selected subalpine forest area. At each stand, the number of tree species and under-canopy herbs ranged from 2 to 4 and 8 to lo respectively. Abies spectabilis, Acer caesium, Quercus floribunda, Q. semecarpifolia and Rhododendron arboreum were key tree species in this area. The density of main woody species was 280 to 119o individuals ha-1 at different stands. Herbaceous plants with rosette and clump growth habits were observed to have higher values for total basal cover and importance value index. presence of some under- canopy herbs like; Dactylorhiza hatagirea, Malaxis muscifera, picrorhiza kurrooa, polygonatum cirrhifolium habitats also and Skimmia laureola showed that they are in the habitat specific specific. However, the presence of Frageria nubicola and Viola sp. was common in the selected stands. Felling of trees for timber, construction of temporary huts, fuel wood and lopping for fodder were main interferences for trees. On the other hand, trampling driven damage due to grazing, habitats degradation and overexploitation were observed key threats for under-canopy herbs. Integrated analysis including population studies, habitats preference and interferences to the trees and under-canopy herbs in this sensitive and important ecosystem will be useful for determining the conservation plans and ecosystem management.

关键词： Conservation Habitat preferences Interferences Management population analysis