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Journal of semiconductors 2014年第4期35卷 48-51页

作者： s.theodore chandra N.B.Balamurugan National Instruments Electronics Laboratory Department of ECE Thiagarajar College of Engineering

We have analyzed the effective oxide thickness （EOT） of the dielectric material for which we have optimum performance and the output characteristics of the silicon nanowire transistors by replacing the traditional si02 gate insulator with a material that has a much higher dielectric constant （high-k） gate, materials like si3N4, Al2O3, Y2O3 and HfO2. We have also analyzed the channel conductance, the effect of a change in thickness, the average velocity of the charge carrier and the conductance efficiency in order to study the performance of silicon nanowire transistors in the nanometer region. The analysis was performed using the Fettoy, a numerical simulator for ballistic nanowire transistors using a simple top of the barrier （Natori） approach, which is composed of several matlab scripts. Our results show that hafnium oxide （HfO2） gate insulator material provides good thermal stability, a high recrystallization temperature and better interface qualities when compared with other gate insulator materials; also the effective oxide thickness of lifO2 is found to be 0.4 nm.

关键词： high-k dielectric hafnium oxide silicon nanowire transistor effective oxide thickness

subthreshold behavior of AlInsb/Insb high electron mobility transistors

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Chinese Physics B 2015年第7期24卷 360-364页

作者： s.theodore chandra N.B.Balamurugan G.Lakshmi Priya s.Manikandan Department of Electronics and Communication Engineering Thiagarajar College of Engineering

We propose a scaling theory for single gate Al In sb/In sb high electron mobility transistors（HEMTs） by solving the two-dimensional（2D） Poisson equation. In our model, the effective conductive path effect（ECPE） is taken into account to overcome the problems arising from the device scaling. The potential in the effective conducting path is developed and a simple scaling equation is derived. This equation is solved to obtain the minimum channel potential Φdeff,minand the new scaling factor α to model the subthreshold behavior of the HEMTs. The developed model minimizes the leakage current and improves the subthreshold swing degradation of the HEMTs. The results of the analytical model are verified by numerical simulation with a sentaurus TCAD device simulator.

关键词： scaling theory subthreshold behavior effective conducting path effect short channel effect

Analysis of charge density and Fermi level of Al In sb/In sb single-gate high electron mobility transistor

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Journal of semiconductors 2015年第6期36卷 47-52页

作者： s.theodore chandra N.B.Balamurugan M.Bhuvaneswari N.Anbuselvan N.Mohankumar National Instruments Electronics Laboratory Department of ECE Thiagarajar College of Engineering Department of ECE SKP Engineering College

A compact model is proposed to derive the charge density of the AlInsb/Insb HEMT devices by con- sidering the variation of Fermi level, the first subband, the second subband and sheet carrier charge density with applied gate voltage. The proposed model considers the Fermi level dependence of charge density and vice versa. The analytical results generated by the proposed model are compared and they agree well with the experimental results. The developed model can be used to implement a physics based compact model for an Insb HEMT device in sPICE applications.

关键词： charge density Fermi level high electron mobility transistor 2D analytical model

Compact analytical model for single gate AlInsb/Insb high electron mobility transistors

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Journal of semiconductors 2014年第11期35卷 46-50页

作者： s.theodore chandra N.B.Balamurugan G.subalakshmi T.shalini G.Lakshmi Priya National Instruments Electronics Laboratory Department of ECEThiagarajar College of Engineering

We have developed a 2D analytical model for the single gate Allnsb/lnsb HEMT device by solving the Poisson equation using the parabolic approximation method. The developed model analyses the device perfomance by calculating the parameters such as surface potential, electric field distribution and drain current. The high mobility of the AlInsb/Insb quantum makes this HEMT ideal for high frequency, high power applications. The working of the single gate Allnsb/Insb HEMT device is studied by considering the variation of gate source voltage, drain source voltage, and channel length under the gate region and temperature. The carrier transport efficiency is improved by uniform electric field along the channel and the peak values near the source and drain regions. The results from the analytical model are compared with that of numerical simulations （TCAD） and a good agreement between them is achieved.

关键词： high electron mobility transistor AlInsb/Insb quantum well 2D analytical model Poisson's equation surface potential electric field

CALCULATIONs OF OPTIMUM PHAsE MATCH PARAMETERs FOR THE BIAXIAL CRYsTAL KTiOPO4

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天津大学学报 1983年第1期 97-104页

作者： theodore s.Fahlen

The expression for the effective nonlinear coefficient deff of a biaxial crystal such as KTiOPO4 （KTP） is presented and numerically calculated. The theoretical walk-off angle, the influence of mismatching, and critical crystal length are discussed, alld finally the optimum phase matching angle is determined. The results provide some theoretical and practical guidance for optinum operation Of biaxial crystals.

关键词： KTP CALCULATIONs OF OPTIMUM PHAsE MATCH PARAMETERs FOR THE BIAXIAL CRYsTAL KTiOPO4

Electro-osmotic flow of a second-grade fluid in a porous microchannel subject to an AC electric field

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Journal of Hydrodynamics 2013年第2期25卷 309-316页

作者： MIsRA J. C. chandra s. Department of Mathematics Institute of Technical Education and Research Siksha O Anusandhan University Department of Physics Sabang S. K. Mahavidyalaya Vidyasagar University

studies on electro-osmotic flows of various types of fluids in microchannel are of great importance owing to their multifold applications in the transport of liquids, particularly when the ionized liquid flows with respect to a charged surface in the presence of an external electric field. In the case of viscoelastic fluids, the volumetric flow rate differs significantly from that of Newtonian fluids, even when the flow takes place under the same pressure gradient and the same electric field. With this end in view, this paper is devoted to a study concerning the flow pattern of an electro-osmotic flow in a porous microchannel, which is under the action of an alternating electric field. The influence of various rheological and electro-osmotic parameters, e.g., the Reynolds number, Debye-Huckel parameter, shape factor and fluid viscoelasticity on the kinematics of the fluid, has been investigated for a secondgrade viscoelastic fluid. The problem is first treated by using analytical methods, but the quantitative estimates are obtained numerically with the help of the software MATHEMATICA. The results presented here are applicable to the cases where the channel height is much greater than the thickness of the electrical double layer comprising the stern and diffuse layers. The study reveals that a larger value of the Debye-Huckel parameter creates sharper profile near the wall and also that the velocity of electro-osmotic flow increases as the permeability of the porous microchannel is enhanced. The study further shows that the electro-osmotic flow dominates at lower values of Reynolds number. The results presented here will be quite useful to validate the observations of experimental investigations on the characteristics of electro-osmotic flows and also the results of complex numerical models that are necessary to deal with more realistic situations, where electro-osmotic flows come into the picture, as in blood flow in the micro-circulatory system subject to an elect

关键词： electrical double layer Debye length second-grade fluid Ionic energy

p53:updates on mechanisms,biology and therapy(Ⅰ)

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Journal of Molecular Cell Biology 2019年第4期11卷 185-186页

作者： chandra s.Verma Bioinformatics Institute Agency for ScienceTechnology and Research(A*STAR)Singapore 138671 Department of Biological sciences National University of SingaporeSingapore 117543 school of Biological sciences Nanyang Technological UniversitySingapore 637551

In July 2017,the 17th International p53 Workshop was held in *** an attendanee of over 300 scientists from all over the world,the meeting was an outstanding success and many new observations about the p53 pathway were discussed for the first *** enthusiasm to gather these in sights into a form that would be available to the whole community led us and the editors of Journal of Molecular Cell Biology to design a special issue of the journal composed of articles and commentaries from some of the key contributors to the meeting.

关键词： p53 mechanisms biology and therapy

ROBUsT HIGH ORDER CONVERGENCE OF AN OVERLAPPING sCHWARZ METHOD FOR sINGULARLY PERTURBED sEMILINEAR REACTION-DIFFUsION PROBLEMs

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Journal of Computational Mathematics 2013年第5期31卷 509-521页

作者： s. chandra sekhara Ra~ sunil Kumar Department of Mathematics Indian Institute of Technology Delhi Hauz khas New Delhi-110016 India

In this article we propose an overlapping schwarz domain decomposition method for solving a singularly perturbed semilinear reaction-diffusion problem. The solution to this problem exhibits boundary layers of width O（√ε ln（1/√ε）） at both ends of the domain due to the presence of singular perturbation parameter ε. The method splits the domain into three overlapping subdomains, and uses the Numerov or Hermite scheme with a uniform mesh on two boundary layer subdomains and a hybrid scheme with a uniform mesh on the interior subdomain. The numerical approximations obtained from this method are proved to be almost fourth order uniformly convergent （in the maximum norm） with respect to the singular perturbation parameter. Furthermore, it is proved that, for small ε, one iteration is sufficient to achieve almost fourth order uniform convergence. Numerical experiments are given to illustrate the theoretical order of convergence established for the method.

关键词： singular perturbation semilinear reaction-diffusion Overlapping schwarzmethod Robust convergence Numerov scheme.

Game theory-based attack and defense analysis in virtual wireless networks with jammers and eavesdroppers

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Digital Communications and Networks 2021年第3期7卷 327-334页

作者： Bassma s.Alsulami chandra Bajracharya Danda B.Rawat Department of Electrical Engineering and Computer science Howard UniversityWashingtonDC20059USA Department of Electrical Engineering Capitol Technology UniversityLaurelMD20708USA

Dynamic spectrum sharing and cognitive radio networks were proposed to enhance the Radio Frequency(RF)spectrum ***,there are several challenges to realize them in real systems,such as sensing uncertainty causing issues to licensed users,business models for licensed service *** virtualization is regarded as a technology that leverages service level agreements to sublease unused or underutilized RF spectrum that addresses aforementioned issues and helps to significantly enhance the utilization of the RF spectrum,offer improved coverage and capacity of networks,enhance network security and reduce energy *** wireless virtualization,wireless networks'physical substrate is shared and reconfigured dynamically between virtual wireless networks through Mobile Virtual Network Operations(MVNOs).Wireless virtualization with dynamic configurable features of Wireless Infrastructure Providers(WIPs),virtualized wireless networks are vulnerable to a multitude of attacks,including jamming attacks and eavesdropping *** paper investigates a means of defense through the employment of coalition game theory when jammers try to degrade the signal quality of legitimate users,and eavesdroppers aim to reduce secrecy ***,we consider a virtual wireless network where MVNO users'job is to improve their signal to Interference plus Noise Ratio(sINR)while the jammers target to collectively enhance their Jammer Received signal strength(JRss),and an eavesdropper's goal is to reduce the overall secrecy *** results have demonstrated that the proposed game strategies are effective(in terms of data rate,secrecy rate and latency)against such attackers compared to the traditional approaches.

关键词： Game theory based security Virtual wireless networks Jamming and eavesdropping

PEO-PVP BLENDED Na^+ION CONDUCTING sOLID POLYMERIC MEMBRANEs

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Chinese Journal of Polymer science 2013年第11期31卷 1538-1545页

作者： Angesh chandra Department of Applied Physics Shri Shankaracharya Institute of Professional Management & Technology

Polyethylene oxide （PEO）-polyvinylpyrrolidone （PVP） blended Na＋ ion conducting solid polymeric membranes：（1-x） [75PEO：25NaPO3] ＋ x PVP, where 0 〈 x 〈 12 wt%, are reported. The polymeric blending was done using a solvent- free hot-press method. Two orders of conductivity enhancement （σca. 1.07× 10^-5 s·cm^-1） have been achieved with 3 wt% of PVP （i.e. the composition： [97（75PEO：25NaPO3）＋ 3PVP]）, from that of the pure host：（75PEO：25NaPO3）. The conductivity enhancement in PEO-PVP blended solid polymeric membranes have been explained by the ionic conductivity, ionic mobility and mobile ion concentration measurements. Materials characterization and polymer-salt complexation were done with the help of X-ray diffraction （XRD）, scanning electron microscopy （sEM）, differential scanning calorimetry （DsC） and thermo gravimetric analysis （TGA） studies. The temperature dependent conductivity studies have also been done to compute the activation energy （Ea） values from lgσ-1/TArrhenius plots. A solid state polymeric battery was fabricated by using optimum conducting composition of solid polymer electrolyte （sPE OCC）, and some important cell parameters were also calculated from the discharge profile of the cell.

关键词： Polymer blending Activation energy Ionic conductivity sEM XRD DsC TGA.