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Cognitive Radios： A Survey On Spectrum Sensing, Security and Spectrum Handoff

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China Communications 2017年第11期14卷 185-208页

作者： Vishakha Ramani Sanjay k.sharma ECE Department University Institute of Technology Rajiv Gandhi Proudyogiki Vishwavidyalaya Ringgold Standard Institution Airport Bypass Road Bhopal Madhya Pradesh Bhopal Bhopal 462036 India

Pervasive wireless computing and communication have created an ever-increasing demand for more radio spectrum. Since, most of the spectrum is underutilized, it motivated the introduction of the concept of cognitive radios, a dynamic spectrum access enabling technology. The first stage of cognitive radio is to sense the environment and determine which parts of the spectrum are available. This is achieved through spectrum sensing. However, spectrum sensing poses the most fundamental challenge in cognitive radios. Moreover, cognitive radios suffer from many vulnerabilities and the security attacks can severely degrade the performance of cognitive radios. This paper surveys state-of-theart research on spectrum sensing and security threats in cognitive radios. Lastly, we also consider the analysis of issues related to spectrum handoffs in cognitive radios.

关键词： cogntive radio spectrum sesning security spectrum handoff

Sequential decay analysis of^(235)U(n^(th),f)reaction using fragmentation approach

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Chinese Physics C 2024年第6期48卷 145-154页

作者： Nitin sharma Ashutosh kaushik Manoj k.sharma School of Physics and Materials Science Thapar Institute of Engineering&TechnologyPatiala-147004PunjabIndia

Numerous experimental and theoretical observations have concluded that the probability of the three fragment emission(ternary fission)or binary fission increases when one proceeds towards the heavy mass region of nuclear periodic *** factors affect fragment emission,such as the shell effect,deformation,orientation,and fissility *** and ternary fissions are observed for both ground and excited states of the *** collinear cluster tripartition(CCT)channel of the^(235)U(n^(th),f)reaction is studied,and we observe that the CCT may be a sequential or simultaneous emission *** date,different approaches have been introduced to study the CCT process as a simultaneous or sequential process,but the decay dynamics of these modes have not been not fully *** the three fragments of the sequential process and exploring their related dynamics using an excitation energy dependent approach would be of further ***,in this study,we investigate the sequential decay mechanism of the^(235)U(n^(th),f)reaction using quantum mechanical fragmentation theory(QMFT).The decay mechanism is considered in two steps,where initially,the nucleus splits into an asymmetric *** the second step,the heavy fragment obtained in the first step divides into two *** I analysis is conducted by calculating the fragmentation potential and preformation probability for the spherical and deformed choices of the decaying *** most probable fragment combination of stage I are identified with respect to the dips in the fragmentation structure and the corresponding maxima of the preformation probability(P0).The light fragments of the identified decay channels(obtained in step I)agree closely with the experimentally observed *** excitation energy of the decay channel is calculated using an iteration *** excitation energy is shared using an excitation energy dependent level density *** obtained excitation

关键词： fission cluster radioactivity ternary fission spontaneous fission cluster model total kinetic energy preformation probability

Study of various ground state decay mechanisms of Actinide nuclei

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Chinese Physics C 2023年第10期47卷 197-212页

作者： Chahat Jindal Nitin sharma Manoj k.sharma School of Physics and Materials Science Thapar Institute of Engineering&TechnologyPatiala-147004PunjabIndia

The special property of the actinide mass region is that nuclei belonging to this group are radioactive and undergo different ground state processes,such as alpha decay,cluster radioactivity(CR),heavy particle radioactivity(HPR),and spontaneous fission(SF).In this study,the probable radioactive decay modes of the heavy mass region(Z=89−102)are studied within the framework of the preformed cluster model(PCM).In the PCM,the radioactive decay modes are explored in terms of the preformation probability(P0)and penetration probability(P)at the turning point Ra,where the penetration of fragments is initiated[Ra=RT(touching state)+ΔR(neck length parameter)].First,the alpha decay half-lives are calculated for light and heavy nuclei,and Ra points are obtained by optimizing the neck length *** Ra points are further employed to fix the Q-value dependent turning point(Ra(Q)).Then,using the(Ra(Q))relation,the decay half-lives are computed,and the calculated results are compared with the available theoretical and experimental *** isotopical trend of P0 and P is studied with respect to the mass number of the parent and daughter nucleus,*** CR and HPR channels are also explored,and a comparison of calculated data is conducted with the available *** analysis of the fragmentation potential and preformation probability is carried out for alpha decay and *** mass distribution of the nuclei is studied as a function of fragment mass(A2)by considering the spherical and hot-compact deformation of the decaying ***,the most probable fission fragments are identified using the fragmentation structure,and the corresponding fission fragment total kinetic energy of the identified fragments is calculated and compared with available data,wherever applicable.

关键词： Alpha decay cluster radioactivity spontaneous fission heavy particle radioactivity ground state decay

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

Dynamics of Entanglement in Qubit-Qutrit with x-Component of DM Interaction

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Communications in Theoretical Physics 2016年第3期65卷 278-284页

作者： kapil k.sharma S.N.Pandey Department of Physics Motilal Nehru National Institute of Technology

In this present paper,we study the entanglement dynamics in qubit A-qutrit B pair under x component of Dzyaloshinshkii-Moriya interaction(D_x)by taking an auxiliary qubit ***,we consider an entangled qubit-qutrit pair initially prepared in two parameter qubit-qutrit states and one auxiliary qubit prepared in pure state interacts with the qutrit of the pair through DM *** trace away the auxiliary qubit and calculate the reduced dynamics in qubit A-qutrit B pair to study the influence of the state of auxiliary qubit C and D_x on *** find that the state(probability amplitude)of auxiliary qubit does not influence the entanglement,only D_x influences the *** phenomenon of entanglement sudden death(ESD)induced by D_x has also been *** also present the affected and unaffected two parameter qubit-qutrit states by D_x.

关键词： entanglement dynamics qubit-qutrit DM interaction ESD

Numerical Investigation of Convective Heat Transfer and Friction in Solar Air Heater with Thin Ribs

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Computer Modeling in Engineering & Sciences 2018年第3期114卷 295-319页

作者： Sanjay k.sharma V.R.kalamkar VNIT Nagpur

The three-dimensional numerical investigation of an incompressible flow through rib roughened solar air heater is carried out.A combination of thin transverse and truncated ribs is attached on the absorber plate to study its effect on the heat transfer and friction *** parameters in the form of Reynolds number(Re)of 4000-16000,relative roughness pitch(P/e)of 8-18 and relative roughness height(e/Dh)of 0.0366-0.055 is considered for the *** CFD code ANSYS FLUENT is used to solve the governing equations of turbulent *** RNG k-εturbulence model is used to solve the transport equations with enhanced wall treatment,keeping the Y+<*** maximum enhancement ratio of the Nusselt number and friction factor obtained is 1.91 and 3.61 *** detailed investigation on average heat transfer,friction factor and flow structures have been discussed.

关键词： CFD 3D heat transfer friction factor

Fusion of spherical-octupole pairs of colliding nuclei for compact and elongated configurations

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Chinese Physics C 2022年第1期46卷 146-156页

作者： Shivani Jain Manoj k.sharma Raj kumar School of Physics and Materials Science Thapar Institute of Engineering&TechnologyPatiala-147004PunjabIndia

The deformation and associated optimum/uniquely fixed orientations play an important role in the syn-thesis of compound nuclei via cold and hot fusion reactions,respectively,at the lowest and highest barrier *** choice of optimum orientation(0_(op))for the'cold or elongated'and hot or cormpact'fusion configurations of quadrupole(β_(2))deformed nuclei depends only on the+/-signs ofβ_(2)-deformation[***.G:***.31,631-644(2005)].In our recent study[***.C 101,051601(R)2020],we proposed a new sct of Oopt(iferent from the values reported for quadrupole deformed nuclei)after the inclusion of octupole deformation(up to B3)*** the respective 0op1 of B3-deformed nuclei for cold and hot optimum orientations,we analyzed the im-pact of the soft-and rigid-pear shapes of octupole deformed nuclei on the fusion barrier characterstics(barrier height Vg and barrier position RB).This analysis is applied to approximately 200 spherical-plus B3 deformed nucle-ar partners,that is,^(16)O,^(18)Cat octupole deformed *** with the compact configuration,the elongated fu-sion configuration has a relatively larger impact on the fusion barrier and cross sections ow ing to the inclusion of de-formations up to *** agreement with available experimental data for the^(16)O+^(150)Sm reaction(β_(22)-0.205,β_(32)=0.055)also improves when the optimum orientation degree of freedom is fixed in view of octupole *** reinforces the fact that nuclear structure effects play an important role in the nuclear fusion ***,octu-pole deformed nuclei can be used for the synthesis of heavy and superheavy nuclei.

关键词： nuclear fusion reactions fusion barrier heavy-ion reactions

Study of Cold Fusion Reactions Using Collective Clusterization Approach

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Communications in Theoretical Physics 2017年第10期67卷 505-517页

作者： Gurjit kaur kirandeep Sandhu Manoj k.sharma School of Physics and Materials Science Thapar University

Within the framework of the dynamical cluster decay model （DCM）, the in evaporation cross-sections （σ1n） of cold fusion reactions （Pb and Bi targets） are calculated for ZCN = 104-113 superheavy nuclei. The calculations are carried out in the fixed range of excitation energy ECN = 15 ± 1 MeV, so that the comparative analysis of reaction dynamics can be worked out. First of all, the fission barriers （Bf ） and neutron separation energies （S1n） are estimated to account the decreasing cross-sections of cold fusion reactions. In addition to this, the importance of hot optimum orientations of β24-deformed nuclei over cold one is explored at fixed angular momentum and neck-length parameters. The hot optimum orientations support all the target-projectile （t,p） combinations, which are explored experimentally in the cold fusion reactions. Some new target-projectile combinations are also predicted for future exploration. Further, the In cross-sections are addressed for ZCN = 104-113 superheavy nuclei at comparable excitation energies which show the decent agrement with experimental data upto ZCN = 109 nuclei. Finally, to understand the dynamics of higher-Z superheavy nuclei, the cross-sections are also calculated at maximum available energies around the Coulomb barrier and the effect of non-sticking moment of inertia （INS） is also investigated at these energies.

关键词： cold fusion reactions ln-decay cross-sections fragment mass distribution

Decay Analysis of Ge Isotopes Formed in Reactions Induced by Tightly and Loosely Bound Projectiles

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Communications in Theoretical Physics 2018年第11期69卷 565-577页

作者： Amandeep kaur kirandeep Sandhu Manoj k.sharma School of Physics and Materials Science Thapar Institute of Engineering and Technology Patiala 147004PunjabIndia Department of Physics GSSDGS Khalsa CollegePatiala 147001PunjabIndia

The dynamical cluster-decay model (DCM) is employed to investigate the decay of ^(6870)Ge~* compound nuclei formed respectively via tightly (~4He) and loosely (~6He) bound projectiles, using ^(64)Zn target. The study is carried out over a wide energy range (E_(c.m.)～5 MeV to 16 MeV) by including the quadrupole deformations (β_(2i)) and optimum orientations (θ_i^(opt)) of the decaying fragments. The fusion cross-sections, obtained by adding various evaporation channels show nice agreement with the experimental data for ~4He+^(64)Zn reaction. The contribution from competing compound inelastic scattering channel is also analyzed particularly for ^(68)Ge~* nucleus at above barrier energies. On the other hand,the decrement in the fusion cross-sections of ^(70)Ge~* nuclear system is addressed by presuming that ^(65)Zn ER is formed via two different modes:(i) the αn evaporation of ^(70Ge)~* nucleus, and(ii) 1n-evaporation of ^(66)Zn~*nuclear system,formed via breakup and 2n-transfer channels due to halo structure of the ~6He projectile. Besides this, the suppression in2 np evaporation cross-sections suggests the contribution of another breakup and transfer process of ~6He i.e. ~4He+ ^(64)*** contribution of breakup+transfer channels for ~6He+^(64)Zn reaction is duly addressed by applying relevant energy corrections due to the breakup of "~6He" projectile into 2n and ~4He. In addition to this, the barrier lowering, angular momentum and energy dependence effects are also explored in view of the dynamics of chosen reactions.

关键词： tightly and loosely bound projectiles evaporation residue breakup and transfer