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Journal of Advanced ceramics 2013年第2期2卷 119-127页

作者： laxman SINGH U.S.rai Alok Kumar rai K.D.MANDAl Department of chemistry Centre of Advanced StudyFaculty of ScienceBanaras Hindu UniversityVaranasi 221005U.P.India Department of Materials Science and Engineering Chonnam National University300 Yongbong-dongBukguGwangju 500-757Republic of Korea Department of Applied chemistry Indian Institute of TechnologyBanaras Hindu UniversityVaranasi 221005U.P.India

The effect of la^(3+),Mn^(2+)and Ni^(2+)doped calcium copper titanate,cacu_(3)Ti_(4)O_(12)(ccTO),at higher concentrations(cR1 and cR2 with 5 mol%and 10 mol%,respectively),has been examined by semi-wet route at relatively lower *** semi-wet route employs citrate-nitrate gel chemical method using TiO_(2) solid powders.X-ray diffraction(XRD)analysis confirms the formation of single phase in the doped samples sintered at 900℃for 8 *** electron micrographs(SEM)show that the average grain size for cR2 is larger than that of cR1 *** energy dispersive X-ray spectroscopy(EDX)is used to study the percentage compositions of different ions present in both *** constant(εr)and dielectric loss(tanδ)values of cR1 are comparatively higher than those of cR2 ceramic at all measured frequencies and *** nature of temperature-dependent relaxation behavior of the ceramics is also studied by impedance,modulus spectroscopic analysis and confirms Maxwell-Wagner relaxation.

关键词： oxide materials chemical synthesis dielectric properties grain boundaries X-ray diffraction(XRD)

Spectroscopy of the ?_(ccb) baryon in the hypercentral constituent quark model

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chinese Physics c 2018年第5期42卷 25-29页

作者： Zalak Shah Ajay Kumar rai Department of Applied Physics Sardar Vallabhbhai National Institute of Technology

We extract the mass spectrum of the triply heavy baryon ?ccbusing the hypercentral constituent quark model. The first order correction is also added to the potential term of the Hamiltonian. The radial and orbital exc... 详细信息

关键词： baryons potential model Regge trajectories

A possible explanation of the Maunder minimum from a flux transport dynamo model

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Research in Astronomy and Astrophysics 2009年第9期9卷 953-958页

作者： Arnab rai choudhuri Bidya Binay Karak Department of Physics Indian Institute of ScienceBangalore-560012India

We propose that the poloidal field at the end of the last sunspot cycle before the Maunder minimum fell to a very low value due to fluctuations in the Babcock-leighton process. With this assumption, a flux transport dynamo model is able to explain various aspects of the historical records of the Maunder minimum remarkably well by suitably choosing the parameters of the model to give the correct growth time.

关键词： Sun: activity -- Sun: magnetic fields -- sunspots

Inhomogeneous Bulk Viscous Fluid Universe with Electromagnetic Field and Variable A-Term

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communications in Theoretical Physics 2008年第7期50卷 279-288页

作者： Anirudh Pradhan Vandana rai Kanti Jotania Department of Mathematics Hindu Post-graduate CollegeZamania-232 331GhazipurIndia Department of Mathematics Post-graduate CollegeGhazipur-233 001India Department of Physics Faculty of ScienceThe M.S.University of BarodaVadodara-390 002India

cylindrically symmetric inhomogeneous cosmological model for bulk viscous fluid distribution with electro- magnetic field is obtained. The source of the magnetic field is due to an electric current produced along the z-axis. F12 is the non-vanishing component of electromagnetic field tensor. To get the deterministic solution, it has been assumed that the expansion 0 in the model is proportional to the shear σ. The values of cosmological constant for these models are found to be small and positive at late time, which are consistent with the results from recent supernovae Ia observations. Physical and geometric aspects of the models are also discussed in presence and absence of magnetic field.

关键词： cosmology variable cosmological term electromagnetic field inhomogeneous universe

Variation in seed morphometric characters, oil content and azadirachtin content of seeds, in vitro shoot cultures and callus cultures among different populations of Azadirachta indica

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Journal of Forestry Research 2018年第1期29卷 121-127页

作者： Fatima Shirin Anamika rai Neelu Singh Genetics and Plant Propagation Division Tropical Forest Research Institute PO RFRC Non-Wood Forest Produce Division Tropical Forest Research Institute PO RFRC

We studied seed morphometric characters, oil content and azadirachtin content in a medicinally important and insect repellent tree species Azadirachta indica ***. Ten populations were selected from two central Indian states of Madhya Pradesh and chhattisgarh and twenty candidate plus trees were selected from each population based on tree attributes. Azadirachtin content was estimated in seeds, in vitro shoots and callus cultures through HPlc. Significant variation（p ／ 0.05） was observed in seed morphometric characters, oil content and azadirachtin content among the ten populations. Maximum value for 100 seed weight was obtained in seeds of raigarh（30.51 g） which was on par with seeds of Bargi（28.37 g）and chhatarpur（26.36 g）. The ratio of highest kernel to seed was also obtained in seeds of raigarh（60.11%）.Kernels from chhatarpur population recorded the highest oil content（24.20%）, which was equal to that in Sihore（23.75%） and Katni（21.75%）. We recorded highly significant variation in azadirachtin content in seed samples,in vitro shoot samples and callus cultures. Maximum azadirachtin was present in the seeds of Gwalior（0.882%）which was on par with azadirachtin content in seeds of chhatarpur, Katni, Sihore, Shahdol and *** azadirachtin in the in vitro shoots was present in the cultures of Gwalior（0.218%） which was statistically on par with Sihore（0.176%）. Similarly, in callus cultures of nodal segments maximum azadirachtin was recorded in the Gwalior population（0.033%） which was statistically on par with Sihore（0.028%）. The trees of Gwalior and Sihore populations can be produced in large numbers through vegetative propagation to obtain seeds with higher azadirachtin content.

关键词： Azadirachtin In vitro Seed morphometric characters Populations Variation

Studies of grand minima in sunspot cycles by using a flux transport solar dynamo model

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Research in Astronomy and Astrophysics 2013年第11期13卷 1339-1357页

作者： Bidya Binay Karak Arnab rai choudhuri Department of Physics Indian Institute of Science

We propose that grand minima in solar activity are caused by simultane- ous fluctuations in the meridional circulation and the Babcock-leighton mechanism for the poloidal field generation in the flux transport dynamo model. We present the following results：（a） fluctuations in the meridional circulation are more effective in producing grand minima; （b） both sudden and gradual initiations of grand minima are possible; （c） distributions of durations and waiting times between grand minima seem to be exponential; （d） the coherence time of the meridional circulation has an effect on the number and the average duration of grand minima, with a coherence time of about 30 yr being consistent with observational data. We also study the occurrence of grand maxima and find that the distributions of durations and waiting times between grand maxima are also exponential, like the grand minima. Finally we address the question of whether the Babcock-leighton mechanism can be operative during grand minima when there are no sunspots. We show that an a-effect restricted to the upper portions of the convection zone can pull the dynamo out of the grand minima and can match various observational requirements if the amplitude of this a-effect is suitably fine-tuned.

关键词： magnetic fields -- (magnetohydrodynamics:) MHD -- Sun: magneticfields -- (Sun:) sunspots

Spectroscopic properties of Δ baryons

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chinese Physics c 2021年第2期45卷 119-125页

作者： chandni Menapara Zalak Shah Ajay Kumar rai Department of Applied Physics Sardar Vallabhbhai National Institute of TechnologySurat-395007GujaratIndia

The resonance state of theΔ baryon,which exists in four isospin(I=3/2)states,has been studied using the hypercentral constituent quark model(hcQM)with a simple linear potential with added first order *** calculated data ranges for 1S-5S,1P-5P,1D-4D and 1F-2F are given,with possible spin-parity assignments for all the *** magnetic moments have also been obtained for all four ***\pidecay channel width has been calculated for a few *** linear nature of the data has been verified through Regge trajectories.

关键词： mass spectra light baryon magnetic moment Regge trajectory

Simulation model for electron irradiated IGZO thin film transistors

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Journal of Semiconductors 2018年第2期39卷 17-21页

作者： G K Dayananda c Shantharama rai A Jayarama Hyun Jae Kim Department of E&c Engineering Canara Engineering College Mangalore 574219 India Department of E&c Engineering AJIET Mangalore 575009 India Department of Physics SCEM Adyar Mangalore 575007 India Yonsei University Seoul 120-749 Republic of Korea

An efficient drain current simulation model for the electron irradiation effect on the electrical parameters of amorphous In–Ga–Zn–O（IGZO） thin-film transistors is developed. The model is developed based on the specifications such as gate capacitance, channel length, channel width, flat band voltage etc. Electrical parameters of un-irradiated IGZO samples were simulated and compared with the experimental parameters and 1 kGy electron irradiated parameters. The effect of electron irradiation on the IGZO sample was analysed by developing a mathematical model.

关键词： simulation model IGZO TFT electron irradiation

Design and investigation of doping-less gate-all-around TFET with Mg_(2)Si source material for low power and enhanced performance applications

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chinese Physics B 2023年第10期32卷 615-624页

作者： Pranav Agarwal Sankalp rai Rakshit Y.A Varun Mishra Graphic Era(deemed to be university) DehradunUttarakhandIndia

Metal–oxide–semiconductor field-effect transistor(MOSFET)faces the major problem of being unable to achieve a subthreshold swing(SS)below 60 mV/*** device dimensions continue to reduce and the demand for high switching ratios for low power consumption increases,the tunnel field-effect transistor(TFET)appears to be a viable device,displaying promising characteristic as an answer to the shortcomings of the traditional *** far,TFET designing has been a task of sacrificing higher ON state current for low subthreshold swing(and vice versa),and a device that displays both while maintaining structural integrity and operational stability lies in the nascent stages of popular *** work presents a comprehensive analysis of a heterojunction plasma doped gate-all-around TFET(HPD-GAA-TFET)by making a comparison between Mg_(2)Si and Si which serve as source *** plasma technique is employed to implement doping in an intrinsic silicon wafer with the help of suitable electrodes.A low-energy bandgap material,*** silicide is incorporated as source material to form a heterojunction between source and silicon-based channel.A rigorous comparison of performance between Si-based GAA-TFET and HPD-GAA-TFET is conducted in terms of electrical,radio frequency(RF),linearity,and distortion *** is observable that HPD-GAA-TFET outperforms conventional Si-based GAA-TFET with an ON-state current(I_(ON)),subthreshold swing(SS),threshold voltage(V_(th)),and current switching ratio being 0.377 mA,12.660 mV/dec,0.214 V,and 2.985×10^(12),***,HPD-GAA-TFET holds faster switching and is more reliable than Si-based ***,HPD-GAA-TFET is suitable for low-power applications.

关键词： subthreshold Mg_(2)Si heterojunction charge plasma gate-all-around(GAA)

Er^(3+)-Yb^(3+)-Na^(+):ZnWO_(4) phosphors for enhanced visible upconversion and temperature sensing applications

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Journal of Rare Earths 2021年第3期39卷 291-296,I0002页

作者： Sonali Biswas lakshmi Mukhopadhyay Manisha Mondal Vineet Kumar rai laser and Spectroscopy laboratory Department of PhysicsIndian Institute of Technology(Indian School of Mines)Dhanbad-826004JharkhandIndia

The crystal structure and surface morphology of the Er^(3+)/Yb^(3+)/Na+:ZnWO_(4) phosphors synthesized by solid state reaction method were analyzed by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM) *** frequency upconversion(Uc) emission study in the developed phosphors was investigated by using 980 nm laser diode *** effect of codoping in the Er^(3+):ZnWO_(4) phosphors on the Uc emission intensity was *** Uc emission bands that are exhibited in the blue(490 nm),green(530,552 nm),red(668 nm) and NIR(800 nm) region correspond to the ^(4)F_(7/2)→^(4)I_(15/2).^(2)H_(11/2),^(4)S_(3/2)→^(4)I_(15/2),^(4)F_(9/2)→^(4)I_(15/2) and ^(4)I9/2→^(4)I_(15/2) transitions,*** temperature sensing performance of the Er^(3+)-Yb^(3+)-Na+:ZnWO_(4) phosphors was investigated based on the 2 H_(11/2)→^(4)I_(15/2) and ^(4)S_(3/2)→^(4)I_(15/2) thermally coupled transitions of the Er^(3+)*** photometric study was also carried out for the developed phosphors.

关键词： Upconversion Non-lanthanides Temperature sensing Fluorescence intensity ratio Rare earths