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Characteristics of a Gan-based Gunn diode for THz signal generation

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Journal of Semiconductors 2012年第8期33卷 37-43页

作者： r K Parida n C Agrawala G n Dash A K panda ITEr Siksha‘O'Anusandhan University rengali College Sambalpur University national Institute of Science&Technology

A generalized large-signal computer simulation program for a Gunn oscillator has been developed. The properties of a Gunn diode oscillator based on the widely explored Gan, are investigated using the developed program. The results show some interesting properties in Gan Gunn diodes which are not seen in GaAs and InP diodes. An output power of 1400 kW/cm^2 is achieved from the Gan Gunn diode, as compared to 4.9 kW/cm^2 from a GaAs diode.

关键词： Gunn devices semiconductor diodes semiconductor materials power Gan

Proton emission from the drip-line nuclei I-Bi using the WKB approximation with relativistic mean-field densities

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Chinese Physics C 2019年第4期43卷 89-99页

作者： T.Sahoo r.n.panda S.K.Patra Physics Department Veer Surendra Sai University of Technology Department of Physics Siksha O Anusandhan Deemed to be University Institute of Physics Homi Bhaba national Institute

We study the properties of proton rich nuclei reported as proton emitters in the region from I to Bi with Z =53 to 83 and n = 56 to 102 as a crucial application to the existence of exotic nuclei. The effective relativistic meanfield formalism(E-rMF), with nL3, FSUGarnet, G3 and IOPB-I interactions, is adopted for analysis of the ground state properties of proton emitters. Furthermore, in the E-rMF background, the Wentzel-Karmers-Brillouin(WKB)barrier penetration method is used for the calculation of proton emission half-lives. It is found that the calculated halflives are in good agreement with the experimental results for all emitters considered in this study.

关键词： effective relativistic mean-field theory nuclear drip line exotic nucleus double folding model WentzelKarmers-Brillouin approximation

rF and microwave characteristics of a 10 nm thick InGan-channel gate recessed HEMT

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Journal of Semiconductors 2013年第11期34卷 36-41页

作者： T.r.Lenka G.n.Dash A.K.panda Department of Electronics and Communication Engineering National Institute of Technology Silchar School of Physics Sambalpur University national Institute of Science and Technology

A new depletion-mode gate recessed A1Gan/InGan/Gan-high electron mobility transistor （HEMT） with 10 nm thickness of InGan-channel is proposed. A growth of A1Gan over Gan leads to the formation of two- dimensional electron gas （2DEG） at the heterointerface. High 2DEG density （ns） is achieved at the heterointerface due to a strain induced piezoelectric effect between A1Gan and Gan layers. The electrons are confined in the InGan-channel without spilling over into the buffer layer, which also reduces the buffer leakage current. From the input transfer characteristics the threshold voltage is obtained as -4.5 V and the device conducts a current of 2 A/mm at a drain voltage of 10 V. The device also shows a maximum output current density of 1.8 A/ram at Vds of 3 V. The microwave characteristics like transconductance, cut-off frequency, max frequency of oscillation and Mason＇s Unilateral Gain of the device are studied by AC small-signal analysis using a two-port network. The stability and power performance of the device are analyzed by the Smith chart and polar plots respectively. To our knowledge this proposed InGan-channel HEMT structure is the first of its kind.

关键词： 2DEG HEMT InGan microwave

Artificial neural network approach to assess selective flocculation on hematite and kaolinite

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International Journal of Minerals,Metallurgy and Materials 2014年第7期21卷 637-646页

作者： Lopamudra panda P.K.Banerjee Surendra Kumar Biswal r.Venugopal n.r.Mandre r&D Tata Steel Limited Institute of Minerals and Materials Technology(Council of Scientific and Industrial research) Department of Fuel & Minerals Engineering Indian School of Mines University

Because of the current depletion of high grade reserves, beneficiation of low grade ore, tailings produced and tailings stored in tailing ponds is needed to fulfill the market demand. Selective flocculation is one alternative process that could be used for the beneficiation of ultra-fine material. This process has not been extensively used commercially because of its complex dependency on process parameters. In this paper, a selective flocculation process, using synthetic mixtures of hematite and kaolinite in different ratios, was attempted, and the ad-sorption mechanism was investigated by Fourier transform infrared （FTIr） spectroscopy. A three-layer artificial neural network （Ann） model （4？4？3） was used to predict the separation performance of the process in terms of grade, Fe recovery, and separation efficiency. The model values were in good agreement with experimental values.

关键词： hematite kaolinite flocculation artificial neural networks back propagation algorithm Fourier transform infrared spectroscopy separation efficiency

Performance evaluation for selectivity of the flocculant on hematite in selective flocculation

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International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1123-1129页

作者： Lopamudra panda Pradip K.Banerjee Surendra Kumar Biswal r.Venugopal n.r.Mandre research and Development Tata Steel Ltd. Institute of Minerals and Materials Technology (Council of Scientific and Industrial research) Indian School of Mines University

Increased demand for iron ore necessitates the utilization of low-grade iron ore fines, slimes, and existing tailings. Selective flocculation can be an alternative physico-chemical process for utilizing these low-grade fines, slimes, and tailings. In selective fiocculation, the most critical objective is the selection of proper reagents that will make fioc of desired minerals. In present study, selective flocculation was applied to ultra-fine synthetic mixtures of hematite and kaolinite, and the Fe value was upgraded up to 65.78% with the reduction of Al2O3 and SiO2 values to 2.65% and 3.6670, respectively. Here, degraded wheat starch was used as a *** this process, separation occurs on the basis of the selectivity of the flocculant. The selectivity of the fiocculant can be quantified in terms of separation efficiency. Here, an attempt was also made to develop a correlation between separation efficiency and major operating parameters such as flocculent dose, pH value, and solid concentration to predict the separation performance.

关键词： hematite kaolinite selective fiocculation modeling iron ores tailings

Constraining the relativistic mean-field models from PrEX-2 data:effective forces revisited

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Chinese Physics C 2022年第9期46卷 218-231页

作者： Jeet Amrit Pattnaik r.n.panda M.Bhuyan S.K.Patra Department of Physics Siksha'O'AnusandhanDeemed to be UniversityBhubaneswar-751030India Center of theoretical and Computational Physics Department of PhysicsUniversity of MalayaKuala Lumpur50603Malaysia Institute of Physics Sachivalya MargBhubaneswar-751005India Homi Bhabha national Institute Training School ComplexAnushakti NagarMumbai 400094India

Based on the current measurement of the neutron distribution radius(r_(n))of ^(208)Pb from the PrEX-2 data,we revisited the recently developed G3 and IOPB-I force parameters by fine-tuning some specific couplings within the relativistic mean-field(rMF)***ω-ρ-mesons coupling and theρ-meson coupling are constrained to the experimental neutron radius of^(208)Pb without compromising the bulk properties of finite nuclei and infinite nuclear matter *** modified parameter sets are applied to calculate the gross properties of finite nuclei such as binding energies,charge distributions,nuclear radii,pairing gaps,and single-particle *** root-mean-square deviations in binding energy and charge radius are estimated with respect to the available experimental data for 195 even-even nuclei,and the results compare favourably with the well-calibrated effective interactions of Skyrme,Gogny and other relativistic mean-field *** pairing gap estimations for modified G3 and IOPB-I for Sn isotopes are also compared with the Hartree-Fock-Bogoliubov calculation with the Gogny(D1S)*** isotopic shift and single-particle energy spacing are also calculated and compared with the experimental data for both original and modified versions of the G3 and IOPB-I parameter ***,both the modified parameter sets are used to obtain the various infinite nuclear matter observables at *** addition to these,the force parameters are adopted to calculate the properties of a high isospin asymmetry dense system such as neutron star matter and tested for validation using the constraint from GW170817 binary neutron star merger *** tuned forces predict relatively good results for finite and infinite nuclear matter systems and the current limitation on the neutron radius from PrEX-2.A systematic analysis using these two refitted parameter sets over the nuclear chart will be communicated shortly.

关键词： relativistic mean field model binding energy charge distribution radius neutron-skin thickness PrEX-2

Idiosyncratic behaviour of(na_(0.49)5K_(0.455)Li_(0.05))(nb_(0.95)Ta_(0.05))O_3-La_2O_3 ceramics: Synergistically improved thermal stability, ageing, and fatigue properties

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Journal of Advanced Ceramics 2019年第1期8卷 79-89页

作者： Bhupender rAWAL n. n. WATHOrE B.PrAVEEnKUMAr H. S. panda Armament research and Development Establishment Department of Materials Engineering Defence Institute of Advanced Technology

La_2 O_3 doped(na0.495 K0.455 Li0.05)(nb0.95 Ta0.05)O_3 ceramics are prepared using modified milling process, and the influences of La2 O3 on ferroelectric behaviour, ageing characteristics, thermal stability, electrical stability, crystal structure, microstructure, dielectric and piezoelectric properties were reported. La_2 O_3 addition improved the ferroelectric characteristic substantially, and obtained remnant polarization(Pr) and maximum strain(Smax) around 34.3 C/cm^2 and 0.13% ***_2 O_3 doped ceramics improved the thermal stability and were stable up to 180 ℃ compared to undoped ceramics(120 ℃). The rietveld refinement along with the high-temperature X-ray diffraction studies suggested the presence of monoclinic phase in La doped compositions, which is responsible for their idiosyncratic behaviour. The maximum values were obtained around 179 pC/n and 0.385 for piezoelectric constant(d33) and electromechanical coupling factor(kp) respectively in La_2 O_3 doped samples(0.02 wt%), which also exhibited the lowest ageing rate and stable electrical fatigue behaviour.

关键词： dielectric fatigue piezoelectric thermal stability

Characterization of electrical properties of AlGan/Gan interface using coupled Schrodinger and Poisson equation

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Journal of Semiconductors 2012年第11期33卷 16-23页

作者： S.Das A.K.panda G.n.Dash national Institute of Science and Technology Palur HillsBerhampurOdisha761008India

The electrical characterization of AlGan/Gan interface is *** dependence of two-dimensional electron gas（2-DEG） density at the interface on the Al mole fraction and thickness of AIGan layer as well as on the thickness of Gan cap layer is *** information can be used to design and fabricate AlGan/Gan based MODFET（modulation doped field effect transistor） for optimum DC and rF characteristics.

关键词： MODFET 2-DEG polarization critical thickness self-heating

nuclear structure study of some bubble nuclei in the light mass region using mean field formalism

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Chinese Physics C 2015年第6期39卷 47-53页

作者： Mahesh K.Sharma r.n.panda Mano j K.Sharma S.K.Patra School of Physics and Material Sciences Thapar University

We study the structural properties of some light mass nuclei using two different formalisms(i) a recently developed simple effective interaction in the frame work of microscopic non-relativistic Hartree-Fock method and(ii)the well-known relativistic mean field approach with nL3 parameter set. The bulk properties like binding energy, root mean square radii and quadrupole deformation parameter are estimated and compared with the available experimental data. The predicted results of both the formalisms are well comparable with the experimental observations. The analysis of density profiles of these light mass nuclei suggest that22 O,23F,34 Si and46Ar have bubble like structure.

关键词： binding energy charge radius relativistic mean field simple effective interaction non-relativistic mean fields