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Asymptotic Study to the n-Dimensional Radial Schrdinger Equation for the Quark-Antiquark System

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Communications in Theoretical Physics 2013年第5期59卷 528-532页

作者： Ramesh kumar Fakir chand Department of Physics Kurukshetra University

Here an asymptotic study to the n-dimensional radial Schrdinger equation for the quark-antiquark interaction potential employing asymptotic iteration method via an ansatz to the wavefunction is carried out. The complete energy spectra of the consigned system is obtained by computing and adding energy eigenvalues for ground state, for large " r" and for small " r". From this analysis, the mass spectra of heavy quarkonia is derived in three dimensions. Our analytical and numerical results are in good correspondence with other experimental and theoretical studies.

关键词： n-dimensional radial Schrodinger equation quarkonium potential eigenvalue eigenfunction

A 2DEG charge density based drain current model for various Al and In molefraction mobility dependent nano-scale AlInGan/Aln/Gan HEMT devices

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Journal of Semiconductors 2013年第4期34卷 24-29页

作者： Godwin Raj Hemant Pardeshi Sudhansu kumar Pati n Mohankumar chand.n kumar sarkar nano Device Simulation Laboratory Electronics and Telecommunication Engineering DepartmentJadavpur UniversityKolkata-700 032India SKP Engineering College TiruvannamalaiTamilnadu-606 611India

We present a two-dimensional electron gas （2DEG） charge-control mobility variation based drain cur- rent model for sheet carrier density in the channel. The model was developed for the AIInGan/A1n/Gan high- electron-mobility transistor. The sheet carrier density model used here accounts for the independence between the Fermi levels Ef and ns along with mobility for various AI and In molefractions. This physics based ns model fully depends upon the variation of El, u0, the first subband E0, the second subband El, and as. We present a physics based analytical drain current model using ns with the minimum set of parameters. The analytical resuks obtained are compared with the experimental results for four samples with various molefraction and barrier thickness. A good agreement between the results is obtained, thus validating the model.

关键词： 2DEG Fermi level AlInGan

Flicker and thermal noise in an n-channel underlap DG FinFET in a weak inversion region

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Journal of Semiconductors 2013年第2期34卷 31-36页

作者： Sudhansu kumar Pati Hemant Pardeshi Godwin Raj n Mohankumar chand.n kumar sarkar nano Device Simulation Laboratory Electronics and Telecommunication Engineering DepartmentJadavpur University SKP College of Engineering TiruvannamalaiTamilnadu-606 611India

We propose an analytical model for drain current and inversion charge in the subthreshold region for an underlap DG FinFET by using the minimum channel potential method, i.e., the virtual source. The flicker and thermal noise spectral density models are also developed using these charge and current models expression. The model is validated with already published experimental results of flicker noise for DG FinFETs. For an ultrathin body, the degradation of effective mobility and variation of the scattering parameter are considered. The effect of device parameters like gate length Lg and underlap length Lun on both flicker and thermal noise spectral densities are also analyzed. Increasing Lg and Lun, increases the effective gate length, which reduces drain current, resulting in decreased flicker and thermal noise density. A decrease of flicker noise is observed for an increase of frequency, which indicates that the device can be used for wide range of frequency applications.

关键词： flicker noise thermal noise ultrathin body virtual source underlap DG FinFET

Effect of underlap and gate length on device performance of an AlInn/Gan underlap MOSFET

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Journal of Semiconductors 2012年第12期33卷 16-22页

作者： Hemant Pardeshi Sudhansu kumar Pati Godwin Raj n Mohankumar chand.n kumar sarkar nano Device Simulation Laboratory Electronics and Telecommunication Engineering DepartmentJadavpur University SKP Engineering College

We investigate the performance of an 18 nm gate length AIInn/Gan heterostructure underlap double gate MOSFET, using 2D Sentaurus TCAD simulation. The device uses lattice-matched wideband Al0.83In0.17n and narrowband Gan layers, along with high-k Al2O3 as the gate dielectric. The device has an ultrathin body and is designed according to the ITRS specifications. The simulation is done using the hydrodynamic model and interface traps are also considered. Due to the large two-dimensional electron gas （2DEG） density and high velocity, the maximal drain current density achieved is very high. Extensive device simulation of the major device performance metrics such as drain induced barrier lowering （DIBL）, subthreshold slope （SS）, delay, threshold voltage （Vt）, Ion/Ioff ratio and energy delay product have been done for a wide range of gate and underlap lengths. Encouraging results for delay, Ion, DIBL and energy delay product are obtained. The results indicate that there is a need to optimize theIoff and SS values for specific logic design. The proposed AlInn/Gan heterostructure underlap DG MOSFET shows excellent promise as one of the candidates to substitute currently used MOSFETs for future high speed applications.

关键词： MOS-HEMT underlap heterostructure ultrathin body interface traps effective mass

A two-dimensional analytical-model-based comparative threshold performance analysis of SOI-SOn MOSFETs

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Journal of Semiconductors 2011年第10期32卷 32-38页

作者： Sanjoy Deb Saptarsi Ghosh n Basanta Singh A K De Subir kumar sarkar Department of Electronics&Telecommunication Engineering Jadavpur University Department of Electronics&Communication Engineering Manipur Institute of Technology Department of Electronics&Communication Engineering National Institute of Technology

A generalized threshold voltage model based on two-dimensional Poisson analysis has been developed for SOI/SOn *** short channel field effects,such as fringing fields,junction-induced lateral fields and substrate fields,are carefully investigated,and the related drain-induced barrier-lowering effects are incorporated in the analytical threshold voltage *** analytical model-based simulation,the threshold voltage roll-off and subthreshold slope for both structures are compared for different operational and structural parameter *** of analytical simulation are compared with the results of the ATLAS 2D physics-based simulator for verification of the analytical *** performance of an SOn MOSFET is found to be significantly different from a conventional SOI *** short channel effects are found to be reduced in an SOn,thereby resulting in a lower threshold voltage roll-off and a smaller subthreshold *** type of analysis is quite useful to figure out the performance improvement of SOn over SOI structures for next generation short channel MOS devices.

关键词： silicon-on-insulator silicon-on-nothing Poisson's equation short channel effects threshold voltage roll-off subthreshold slope

A new approach to extracting the RF parameters of asymmetric DG MOSFETs with the nQS effect

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Journal of Semiconductors 2013年第11期34卷 31-35页

作者： Sudhansu kumar Pati Kalyan Koley Arka Dutta n Mohankumar chand.n kumar sarkar nano Device Simulation Laboratory Electronics and Telecommunication Engineering Department Jadavpur University SKP College of Engineering Tiruvannamalai

In analog circuit design an important parameter, from the perspective of superior device performance, is linearity. The DG MOSFET in asymmetric mode operation has been found to present a better linearity. In addi- tion to that it provides, at the discretion of analog circuit designer, an additional degree of freedom, by providing independent bias control for the front and the back gates. Here a non-quasi-static （nQS） small signal model for DGMOSFET with asymmetric gate bias is proposed for extracting the parameters of the device using TCAD sim- ulations. The parameters extracted here for analysis are the intrinsic front and back gate to drain capacitance, Cgal and Cgd2, the intrinsic front and back distributed channel resistance, Rgdl and Rgd2 respectively, the transport de- lay, rm, and the inductance, Lsd. The parameter extraction model for an asymmetric DG MOSFET is validated with pre-established extracted parameter data, for symmetric DG MOSFET devices, from the available literature. The device simulation is performed with respect to frequency up to 100 GHz.

关键词： asymmetric DGMOSFET RF modeling small signal analysis parameter extraction

Infrared Spectra of PH3 and nF_(3): An Algebraic Approach

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Chinese Physics Letters 2013年第7期30卷 9-12页

作者： Joydeep Choudhury nirmal kumar sarkar Ramendu Bhattacharjee Department of Physics Assam UniversitySilchar-788011India Department of Physics Karimganj CollegeKarimganj-788710India

Molecular spectroscopy is a branch of physics which deals with the interaction of electromagnetic radiation with *** the new theoretical approach,i.e.,Lie algebraic approach,we calculate the infrared spectra of phosphine in the range from 3000 cm^(-1) to 9500 cm^(-1) and nitrogen trifluoride in the range from 900 cm^(-1) to 4500 cm^(-1).The model Hamiltonian constructed seems to describe the P–H and n–F stretching modes accurately with only four numbers of *** present calculation not only predicts the higher overtones but also shows good agreement with the few observed data.

关键词： parameters. Infrared stretching

Effects of moisture content and feed rate on milling characteristics of wild apricot pits (Prunus armeniaca L.)

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International Journal of Agricultural and Biological Engineering 2014年第1期7卷 103-110页

作者： A.E.Kate U.C.Lohani n.C.Shahi J.P.Pandey A.sarkar Khan chand Department of Post Harvest Process&Food Engineering College of TechnologyG.B.Pant University of Agriculture and TechnologyPantnagarU.S.Nagar(Uttarakhand)-263145India Department of agricultural and Biological Engineering South Dakota State UniversityBrookingsSD 57006USA

Milling with decortication of wild apricot pits was done in wild apricot pit decorticator working on the principle of“impact and compression”.The milling characteristics includes decortication efficiency,percentage of husk,percentage of broken kernels and output capacity was evaluated at the different levels of moisture content,i.e.,8%,10%,12%,14%and 16%(w.b.)and feed rates,i.e.,12 g/stroke,14 g/stroke,16 g/stroke,18 g/stroke and 20 g/*** moisture content as well as feed rate significantly(Pn efficiency,percentage of husk as well as brokens and output *** efficiency was initially increased and then decreased and opposite nature was found for the percentage of *** percentage of broken kernels and output capacity decreases with the increase in moisture content,while output capacity increases with the increase in feed rate and brokens decreases with the increase in feed rate of wild apricot pits.

关键词： wild apricot pit milling characteristics decortication efficiency moisture content husk percentage broken percentage output capacity

Association of endothelial nitric oxide synthase gene T-786C promoter polymorphism with gastric cancer

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World Journal of Gastrointestinal Oncology 2015年第7期7卷 87-94页

作者： Devulapalli Krishnaveni Bhayal Amar chand Porika Shravan kumar Malladi Uma Devi Macherla Ramanna Akka Jyothy nallari Pratibha n Balakrishna Ananthapur Venkateshwari Department of Cell Biology Institute of Genetics and Hospital for Genetic DiseasesOsmania University Department of Gastroenterology Gandhi Hospital Department of Genetics Osmania University Department of Biostatistics National Institute of NutritionHyderabad

AIM: To investigate the role of endothelial nitric oxide synthase-786 T > C promoter polymorphism in the etiology of gastric cancer(GC). METHODS: A total of 150 GC patients and 150 control subjects were included in the study. The information on demographic features was elicited with an informed consent from all the patients and control subjects using a structured questionnaire. Helicobacter pylori(H. pylori) infectivity status was tested in antral biopsies from all the subjects by rapid urease test following the method of Vaira et al. Genomic DnA was isolated from whole blood samples following the salting out method of Lahiri et al. Genotype analysis of the rs2070744 polymorphism was carried out by allele-specific polymerase chain reaction method. The genotypes were determined based on the appearance of bands on an agarose gel stained with ethidium bromide under ultraviolet gel documentation with the help of 100 bp ladder. Odds ratios and corresponding 95%CIs were determined using java stat online software. RESULTS: There was a significant difference in the distribution of C allele(C vs T; P = 0.000, OR = 5.038) in patient group compared to the control subjects exhibiting a fivefold increased risk for GC. When the T/T and C/C genotypes were compared, there was an enhanced GC risk for individuals with C/C genotype(T/T vs C/C; P = 0.000). Among the demographic factors, smoking and alcoholism were the common risk factors in patients compared to the control subjects(P nts with smoking and alcoholism developed cancer even in heterozygous T/C condition(smoking: P = 0.020 and alcoholism: P = 0.005). Individuals with H. pylori infection showed seven fold increased risk for cancer. All the patients with C/C genotype revealed a significant association between H. pylori infection and GC. Among the patients 2.4% of them revealed familial incidence of GC. no significant difference was noticed between cases and controls with regard to consanguinity(P = 0.473).COnCLU

关键词： Genetics Helicobacter pylori nutrition Oncology Endoscopy Gastro duodenal nitric oxide Single nucleotide polymorphism rs2070744 Agarosegel electrophoresis Allele specific polymerase chainreaction