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Kadomtsev–petviashvili(Kp) Burgers Equation in Dusty Negative Ion plasmas:Evolution of Dust-Ion Acoustic Shocks

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Communications in Theoretical physics 2014年第12期61卷 875-880页

作者： A.N.Dev J.Sarma M.K.Deka a.p.misra N.C.Adhikary Department of Science and Humanities College of Science and Technology RUB Bhutan Department of Mathematics R.G.Baruah College Guwahati-781025 Assam India Centre of plasma physics Tepesia Sonapur Kamrup Assam India Department of Mathematics Siksha Bhavana Visva-Bharati University Santiniketan-731 235 India physical Sciences Division Institute of Advanced Study in Science and Technology Vigyan Path Paschim BoragaonGarchuk Guwahati – 781035 Assam India

We study the nonlinear propagation of dust-ion acoustic(DIA) shock waves in an un-magnetized dusty plasma which consists of electrons, both positive and negative ions and negatively charged immobile dust grains. Starting from a set of hydrodynamic equations with the ion thermal pressures and ion kinematic viscosities included, and using a standard reductive perturbation method, the Kadomtsev–petviashivili–Burgers(K-p-Burgers) equation is derived, which governs the evolution of DIA shocks. A stationary solution of the K-p-Burgers equation is obtained and its properties are analysed with different plasma number densities, ion temperatures and masses. It is shown that a transition from shocks with negative potential to positive one occurs depending on the negative ion concentration in the plasma and the obliqueness of propagation of DIA waves.

关键词： dusty plasmas Shock wave reductive perturbation technique K-p burgers equation

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

Nonlinear ion-acoustic solitary waves in an electron-positron-ion plasma with relativistic positron beam

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Chinese physics B 2018年第10期27卷 471-476页

作者： Ridip Sarma Amar p misra Nirab C Adhikary Department of Mathematics University of Science and TechnologyTechno CityKhanaparaBaridua9th MileRi-BhoiMeghalayaIndia Department of Mathematics Siksha BhavanaVisva-Bharati University physical Sciences Division Institute of Advanced Study in Science and TechnologyVigyan PathPaschim BoragaonGarchukGuwahati-781035AssamIndia

The propagation characteristics of nonlinear ion–acoustic（IA） solitary waves（SWs） are studied in thermal electron–positron–ion plasma considering the effect of relativistic positron beam. Starting from a set of fluid equations and using the reductive perturbation technique, we derive a Korteweg–de Vries（KdV） equation which governs the evolution of weakly nonlinear IA SWs in relativistic beam driven plasmas. The properties of the IA soliton are studied, and it is shown that the presence of relativistic positron beam significantly modifies the characteristics of IA solitons.

关键词： electron-positron-ion plasma relativistic effect ion-acoustic wave homogeneous balance method

Spread and control of COVID-19:A mathematical model

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International Journal of Modeling, Simulation, and Scientific Computing 2022年第3期13卷 121-148页

作者： O.p.misra Omprakash Singh Sisodiya School of Mathematics and Allied Sciences Jiwaji University Gwalior 474011Madhya PradeshIndia

A mathematical model is proposed in this paper to study the transmission and control of *** mathematical model is formulated using system of nonlinear ordinary differential *** model includes disease-related parameters such as contact rate,disease-induced death rates,immigration rate and transition rates along with parameters for control measures such as implementation of social distancing practices,isolation and quarantine *** the stability analysis of the model,it is shown that if the social distancing is practiced by the large number of susceptible population,then the disease will not spread,and it may eventually die ***,it is derived from the analysis of the model that if most of the infected populations are isolated or quarantined,then the spread of the disease can be eventually ***,from the analysis of the model,it is observed that if there is constant immigration of asymptomatic infected persons,then the disease will continue to spread and will remain *** controlling the disease,two more parameters,that is,vaccination and testing rates,are introduced in the original mathematical model and from the numerical analysis of this model,it has been shown that the control strategy involving vaccination and testing in combination can have synergistic effect for minimizing the COVID-19 infected cases.

关键词： COVID-19 social distancing isolation quarantine immigration mathematical model

Nonlinear time series analysis of the light curves from the black hole system GRS1915+105

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Research in Astronomy and Astrophysics 2011年第1期11卷 71-90页

作者： K.p.Harikrishnan Ranjeev misra G.Ambika Department of physics The Cochin College Inter University Centre for Astronomy and Astrophysics Indian Institute of Science Education and Research

GRS 1915＋105 is a prominent black hole system exhibiting variability over a wide range of time scales and its observed light curves have been classified into 12 temporal states. Here we undertake a complete analysis of these light curves from all the states using various quantifiers from nonlinear time series analysis, such as the correlation dimension （D2）, the correlation entropy （K2）, singular value decomposition （SVD） and the multifractal spectrum （f（α） spectrum）. An important aspect of our analysis is that, for estimating these quantifiers, we use algorithmic schemes which we have recently proposed and successfully tested on synthetic as well as practical time series from various fields. Though the schemes are based on the conventional delay embedding technique, they are automated so that the above quantitative measures can be computed using conditions prescribed by the algorithm and without any intermediate subjective analysis. We show that nearly half of the 12 temporal states exhibit deviation from randomness and their complex temporal behavior could be approximated by a few （three or four） coupled ordinary nonlinear differential equations. These results could be important for a better understanding of the processes that generate the light curves and hence for modeling the temporal behavior of such complex systems. To our knowledge, this is the first complete analysis of an astrophysical object （let alone a black hole system） using various techniques from nonlinear dynamics.

关键词： accretion accretion disks -- X-rays: binaries

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

SIRS epidemic modeling using fractional-ordered differential equations:Role of fear effect

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International Journal of Biomathematics 2024年第5期17卷 79-100页

作者： Shiv Mangal O.p.misra Joydip Dhar School of Mathematics and Allied Sciences Jiwaji University GwaliorMadhya PradeshIndia Department of Mathematics Post Graduate College BinaMadhya PradeshIndia Department of Applied Sciences Atal Bihari Vajpayee-Indian Institute of Information Technology and Management GwaliorMadhya PradeshIndia

In this paper,an SIRS epidemic model using Grunwald-Letnikov fractional-order derivative is formulated with the help of a nonlinear system of fractional differential equations to analyze the effects of fear in the population during the outbreak of deadly infectious *** criteria for the spread or extinction of the disease are derived and discussed on the basis of the basic reproduction *** condition for the existence of Hopf bifurcation is discussed considering fractional order as a bifurcation ***,using the Grunwald-Letnikov approximation,the simulation is carried out to confirm the validity of analytic results *** the real data of COVID-19 in India recorded during the second wave from 15 May 2021 to 15 December 2021,we estimate the model parameters and find that the fractional-order model gives the closer forecast of the disease than the classical *** the analytical results and numerical simulations presented in this study suggest different policies for controlling or eradicating many infectious diseases.

关键词： SIRS epidemic model fear effect Mittag-Leffler function Hopf bifurcation parameter estimation

Ileoscopy in patients with ileocolonic tuberculosis

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World Journal of Gastroenterology 2007年第11期13卷 1723-1727页

作者： Sp misra Vatsala misra Manisha Dwivedi Department of Gastroenterology and pathology Moti Lal Nehru Medical College University of Allahabad Allahabad 211 001 India

AIM: To study the role of retrograde terminal ileoscopy in patients suspected to have ileocolonic tuberculosis. METHODS: A retrospective analysis was performed for patients undergoing colonoscopy for suspected ileocolonic tuberculosis between January 2000 and June 2004, in whom retrograde ileoscopy had been performed. Only patients diagnosed with tuberculosis on the basis of histological findings of either a caseating granuloma or those having non-caseating granuloma or a collection of epithelioid cells at a minimum of one endoscopic lesion (either in the colon or the terminal ileum) on histology with good responses to conventional anti-tuberculous drugs were enrolled for the study. RESULTS: Fifty-three patients were included. The terminal ileum was involved in only 11 patients. Eight of these patients had involvement of the cecum too. Two patients had ileal lesions without cecal involvement; however, lesions were noted in the ascending colon. In one patient the whole colon was normal and only the terminal ileum showed nodularity and ulceration. Histological examination of the ileal biopsies obtained from the ileal lesions showed noncaseating granulomas in five, collection of epithelioid cells in four and nonspecific histology in two patients. Mucosal biopsies obtained from the lesion in the terminal ileum, in the patient in whom mucosal abnormality was observed to be confined to the ileum, showed noncaseating granulomas. In two other patients the ileal biopsies alone showed histological evidence of tuberculosis with biopsies from the colonic lesions showing non-specific inflammatory changes only. CONCLUSION: Retrograde ileoscopy should be performed in all patients undergoing colonoscopy for suspected ileocolonic tuberculosis. In some patients only the terminal ileum may be involved and histological examination may reveal evidence of tuberculosis only from the lesions in the terminal ileum. This approach would lead to additional lesions being picked up andincreasing

关键词： Tuberculosis Ileoscopy Colonoscopy

Ileoscopy in 39 hematochezia patients with normal colonoscopy

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World Journal of Gastroenterology 2006年第19期12卷 3101-3104页

作者： Sp misra M Dwivedi V misra Department of Gastroenterology and pathology Moti Lal Nehru Medical College Allahabad 211001India

AIM： To assess the role of retrograde terminal ileoscopy in hematochezia patients with normal colonoscopy. METHODS： Between January 1997 and March 2005, 39 hematochezia patients （males 36, females 3, mean age 44.7 years） with a reported normal colonoscopy underwent a repeat colonoscopy. After reaching the cecum, attempt was made to localize the ileocecal valve and intubate the terminal ileum. Any abnormality in the mucosa of the terminal ileum was carefully recorded and biopsies were obtained from suspiciouslooking lesions. RESULTS： During the study period there were 39 patients admitted for hematochezia in whom colonoscopy till cecum did not reveal any abnormality. Fulllength colonoscopy till the cecum could be performed in all the patients. The terminal ileum could be intubated in 36 patients. No abnormality was noted in 31 patients. Ileal ulcers were noted in two patients. Noclularity along with ulceration of the ileal mucosa, a Dieulafoy＇s lesion, and an angiomatous malformation were noted in one patient each. Histological examination of the biopsies obtained from the ulcers revealed typical tuberculous lesion in the patient with nodularity and ulceration. One of the patients had typhoid ulcers and another had non-specific ulcers. CONCLUSION： Retrograde terminal ileoscopy gives limited but valuable information, in patients with hematochezia and should be attempted in all such patients.

关键词： Endoscopy Ileum Colon Diagnosis Tuberculosis Ulcer GI bleeding