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Journal of Palaeogeography 2024年第4期13卷 738-753页

作者： B.V.Lakshmi K.Deenadayalan Md.Mujahed Baba saumitra misra Indian Institute of Geomagnetism New PanvelNavi Mumbai 410218India Discipline of Geological Sciences SAEESUniversity of KwaZulu-NatalDurban 4000South Africa

Anisotropy of Magnetic Susceptibility(AMS)data from a~27.8 m thick soft sedimentary mud sequence(~10.5-3.25 k yrs)from the Spituk Palaeolake Sequence(SPSS)of Holocene age,located in the northern bank of the Indus River in the Leh-Ladakh Himalaya,show effects of tectonic versus climate dynamics responsible for the Himalayan *** sedimentary sequence,consisting of alternating of aeolian sand and glacio-fluvial mud flow deposits,has been subdivided into an older Last Glacier Phase I(LGP 1)and a younger Last Glacier Phase II(LGP 2),where the termination of each phase is marked by the occurrence of gravel beds of thickness≤1 m,which were deposited due to glacial *** present AMS data along with previously published information on sedimentology confirm that the mudflow deposits of the LGP 1 and LGP 2phases were deposited in a lacustrine environment under glacio-fluvial ***,a weak fluvial flow towards NW and NE could have existed for the LGP 1 and LGP 2,*** glacial beds terminating LGP 1 and LGP 2 appear to have formed by climatic warming and tectonic activity,***,the Holocene Himalayan sedimentation was influenced by both climatic and tectonic ***,the thickness of the gravel bed(~0.8 m)terminating LGP 2 occupies only~2.8 vol%of the total studied thickness~28 m,of the SPSS in the present study,which indicated a lesser control of tectonism in the growth of the Himalaya in and around the study area.

关键词： Holocene palaeolake sequence AMS studies Gravel beds Deglaciation Tectonic instability

A Petrogenetic Model of Basalts from the Northern Central Indian Ridge:3-11°S

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Acta Geologica Sinica(English Edition) 2007年第1期81卷 99-112页

作者： Dwijesh RAY Sridhar D. IYER Ranadip BANERJEE saumitra misra M. WIDDOWSON Geological Oceanography Division National Institute of Oceanography Goa-403 004 India Department of Geology and Geophysics Indian Institute of Technology Kharagpur-721 302 India Department of Earth Sciences Open University Milton Keynes MK7 6AA U.K.

Mid-Ocean Ridge Basalts （MORB） from the Northern Central Indian Ridge （NCIR） were recovered between latitudes 3° and 11° S and are olivine tholeiite with higher abundances of K and Rb. They are of typical transitional MORB （T-MORB） variety and appear to have been generated from an enriched-mantle peridotite source. The primitive NCIR MORBs having Mg^# 〉 0.68 are the product of partial melting at an estimated pressure of - 1 GPa. It is inferred that the magma was subsequently modified at a pressure 〉 1 GPa by crystal fractionation and spinel was the first mineral to crystallize followed by separation of relatively Fe-rich olivine with subsequent decrease in pressure. During progressive fractionation at lower pressure （between 1-0.5 GPa）, the bulk composition of the magma became systematically depleted in MgO, and enriched in ∑FeO, TiO2, P2Os and Na20. There was, however, limited gradual depletion in Al2O3 and CaO and concomitant enrichment in K20. With the progressive fractionation these basalts became gradually enriched in V, Co, Y, Zr and to some extent in Sr, and depleted in Ni and Cro In addition, the T_JtEE of the magma also increased with fractionation, without any change in （La/Yb）n value.

关键词： MORB NCIR geochemistry petrogenesis Indian Ocean mid-ocean ridge

A novel approach towards molecular memory device in gate tunable structure of MoS_(2)-graphene

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Nano Research 2021年第1期14卷 177-184页

作者： Rahul Tripathi Abha misra Department of Instrumentation and Applied Physics Indian Institute of Sciencey BangaloreKarnataka 560012India

Molecular interaction in two-dimensional(2D)van der Waals(vdW)interfaces has drawn tremendous attention for extraordinary materials *** sensing characteristics of molecular interaction has been exploited extensively to reach the detection limit to a few parts-per-billion(ppb)of molecules and far less attention is given to the evolution of persistent current state due to the molecular *** study focuses on molecular memory operation of MoS_(2)-graphene heterostructure based field effect *** resistance state of the device due to the external perturbation of molecules is tuned to get a nearly relaxation free current state at much lower molecular concentration of 10 ppb tofacilitate non-volatile memory features for molecular memory *** ultrafast switching operation in milli-second order is achieved at room temperature for the fastest recovery obtained sofar in any molecular *** process is co-controlled both by molecular as well as external charge density.

关键词： MoS_(2) graphene field effect transistor molecular memory trap charges

Surface plasmon oscillations in a semi-bounded semiconductor plasma

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Plasma Science and Technology 2018年第2期20卷 76-81页

作者： M SHAHMANSOURI A P misra Department of Physics Faculty of ScienceArak University Department of Mathematics Siksha BhavanaVisva-Bharati University

We study the dispersion properties of surface plasmon（SP） oscillations in a semi-bounded semiconductor plasma with the effects of the Coulomb exchange（CE） force associated with the spin polarization of electrons and holes as well as the effects of the Fermi degenerate pressure and the quantum Bohm *** from a quantum hydrodynamic model coupled to the Poisson equation,we derive the general dispersion relation for surface plasma *** results in this context are *** dispersion properties of the surface waves are analyzed in some particular cases of interest and the relative influence of the quantum forces on these waves are also studied for a nano-sized Ga As semiconductor *** is found that the CE effects significantly modify the behaviors of the SP *** present results are applicable to understand the propagation characteristics of surface waves in solid density plasmas.

关键词： surface plasmon oscillations semiconductor plasma semi-bounded plasma

Effect of processing parameters on the electromagnetic radiation emission during plastic deformation and crack propagation in copper-zinc alloys

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1800-1809页

作者： KUMAR Rajeev misra Ashok Department of Mechanical Engineering Birla Institute of Technology Mesra 835215 Ranchi India

This paper presents some investigations on the effect of processing parameters on the emission of electromagnetic radiation （EMR） during plastic deformation and crack propagation in copper-zinc alloys. Timing of the EMR emissions, maximum stress during crack instability, stress-intensity factor, elastic strain energy release rate, maximum EMR amplitude, RMS value of EMR amplitude, EMR frequency and electromagnetic energy release rate were analysed for the effect of rolling directions at different percentage of zinc content in Cu-Zn alloy specimens. The same parameters were also analysed for 68-32 Cu-Zn alloy specimens at different annealing temperatures and at different angles 0, to the rolling direction. EMR emissions are observed to be highly anisotropic in nature. At θ=45° to 60°, marked changes in mechanical and electromagnetic parameters were observed. Specimens annealed at 500℃, just above the recrystallization temperature, and at 700℃, when grain-size growth is rapid, EMR responses have been found to have well-defined patterns.

关键词： Radiation Plastic deformation Rolling direction Annealing Fracture

Electro-osmotic flow and heat transfer of a non-Newtonian fluid in a hydrophobic microchannel with Navier slip

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Journal of Hydrodynamics 2015年第5期27卷 647-657页

作者： misra J.C. SINHA A. Adjunct Professor Centre for Healthcare Science and Technology Indian Institute of Engineering Science and Technology School of Medical Science and Technology Indian Institute of Technology

In this paper, we investigate the implications of electro-osmosis on electrohydrodynamic transport of a non-Newtonian fluid on a hydrophobic micro-channel by developing a suitable analytical method. Velocity-slip and temperature-jump conditions are paid due attention. An attempt has been made to examine the effects of rheological and electro-osmotic parameters on the kinematics of the fluid. The nonlinear Poisson-Boltzmann equation governing the formation of the electrical double layer and the body force that is generated by the applied potential are accounted for in the study. Perturbation solutions are presented. In order to exhibit the applicability of the analysis, the problem of electro-osmotic flow and heat transfer of blood in an arteriole has been taken up as an illustrative example of a real-life problem. An intensive quantitative study has been made through numerical computation of the physical variables involved in the analysis, which are of special interest in the study. The computational results are presented graphically. The study reveals that the temperature of blood can be controlled by increasing/decreasing the Joule heating parameter.

关键词： electro-osmotic flow hydrophobic microchannel electrical double layer viscoelastic fluid velocity-slip temperature-jump

Helicobacter pylori and gastric cancer: Indian enigma

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World Journal of Gastroenterology 2014年第6期20卷 1503-1509页

作者： Vatsala misra Renu Pandey Sri Prakash misra Manisha Dwivedi Department of Pathology Moti Lal Nehru Medical College Pandey Research 3312 Jackson Blvd Department of Gastroenterology and Hepatology MLN Medical College

Helicobacter pylori (H. pylori) is a gram negative microaerophilic bacterium which resides in the mucous linings of the stomach. It has been implicated in the causation of various gastric disorders including gastric cancer. The geographical distribution and etiology of gastric cancer differ widely in different geographical regions and H. pylori, despite being labeled as a grade I carcinogen, has not been found to be associated with gastric cancer in many areas. Studies in Asian countries such as Thailand, India, Bangladesh, Pakistan, Iran, Saudi Arabian countries, Israel and Malaysia, have reported a high frequency of H. pylori infection co-existing with a low incidence of gastric cancer. In India, a difference in the prevalence of H. pylori infection and gastric cancer has been noted even in different regions of the country leading to a puzzle when attempting to find the causes of these variations. This puzzle of H. pylori distribution and gastric cancer epidemiology is known as the Indian enigma. In this review we have attempted to explain the Indian enigma using evidence from various Indian studies and from around the globe. This review covers aspects of epidemiology, the various biological strains present in different parts of the country and within individuals, the status of different H. pylori-related diseases and the molecular pathogenesis of the bacterium.

关键词： Gastric cancer Gastric diseases Helicobacter pylori p53 mutation Carcinogen

Formation of E-cyanomethamine in a nitrile rich environment

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Research in Astronomy and Astrophysics 2017年第1期17卷 1-10页

作者： Shivani Alka misra Poonam Tandon Department of Mathematics & Astronomy University of Lucknow Lucknow India Department of Physics University of Lucknow Lucknow 226007 India

Recently a new molecule, cyanomethamine, has been detected towards Sagittarius B2（N）（Sgr B2（N））. Studying the formation mechanisms of complex interstellar molecules is difficult. Hence, a theoretical quantum chemical approach for analyzing the reaction mechanism describing the forma- tion of interstellar cyanomethamine through detected interstellar molecules and radicals （NCCN＋H） is discussed in the present work. Calculations are performed by using quantum chemical techniques, such as Density Functional Theory （DFT） and Mφ11er-Plesset perturbation （MP2） theory with a 6-311G（d,p） basis set, both in the gas phase and in icy grains. The proposed reaction path （NCCN＋H＋H） has exother- micity with no barrier which indicates the possibility of cyanomethamine formation in the interstellar medium.

关键词： interstellar medium: abundances general - general: extraterrestrial intelligence - mete-orites - individual: Sgr B2(N) region

Electron Paramagnetic Resonance of Mn^(2+)-Doped Cadmium Formate Dihydrate Single Crystals

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Chinese Physics Letters 2012年第3期29卷 208-211页

作者： Indrajeet Mishra Ram Kripal Sanjay misra EPR Laboratory Department of PhysicsUniversity of AllahabadAllahabad21100 India 2Department of Physics Buddha P.G.CollegeKushinagar(U.P.)India

An electron paramagnetic resonance(EPR)study on Mn^(2+)doped Cadmium formate dihydrate single crystals is carried *** EPR spectrum at room temperature exhibits only one out of five fine structural transitions which split into six hyperfine lines in all *** spectrum is simulated using the EasySpin program and evaluated spin Hamiltonian *** simulated EPR spectrum is in good agreement with the *** comparing direction cosines of spectroscopic splitting factor g and the direction cosines of different bonds determined by the crystal structure data it is found that Mn^(2+)enters the lattice substitutionally and only one Mn^(2+)site is *** obtained g and the hyperfine interaction constant A achieved are g=2.006±0.002,A=(98±2)×10^(-4)cm^(-1)and the second-order axial zero-field splitting parameter D=(60±2)×10^(-4)cm^(-1).

关键词： hydrate splitting spectrum

Quantification of grain boundary effects on the geometrically necessary dislocation density evolution and strain hardening of polycrystalline Mg-4Al using in situ tensile testing in scanning electron microscope and HR-EBSD

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Journal of Magnesium and Alloys 2024年第5期12卷 1815-1829页

作者： Eunji Song Mohsen Taheri Andani Amit misra Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA

In situ tensile testing in a scanning electron microscope(SEM)in conjunction with high-resolution electron backscatter diffraction(HR-EBSD)under load was used to characterize the evolution of geometrically necessary dislocation(GND)densities at individual grain boundaries as a function of applied strain in a polycrystalline Mg-4Al *** increase in GND density was investigated at plastic strains of 0%,0.6%,2.2%,3.3% from the area including 76 grains and correlated with(i)geometric compatibility between slip systems across grain boundaries,and(ii)plastic *** develop expressions for the grain boundary GND density evolution as a function of plastic strain and plastic incompatibility,from which uniaxial tensile stress-strain response of polycrystalline Mg-4Al are computed and compared with experimental *** findings in this study contribute to understanding the mechanisms governing the strain hardening response of single-phase polycrystalline alloys and more reliable prediction of mechanical behaviors in diverse microstructures.

关键词： Mg-Al alloys Grain boundaries Geometrically necessary dislocations Strain gradient plasticity HR-EBSD