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Study of Type-B QPOs Observed in Black Hole X-Ray Binary Swift J1728.9-3613

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Research in Astronomy and Astrophysics 2024年第3期24卷 1-9页

作者： raj kumar Astrophysical Sciences Division Bhabha Atomic Research CentreMumbai 400085India Homi Bhabha National Institute Mumbai 400094India

We report the detection of type-B quasi-periodic oscillation(QPO)of the black hole X-ray binary Swift J1728.9-3613 observed by NICER during the 2019 outburst.A type-B QPO was observed for the first two days and it disappeared as flux increased,but again appeared at∼7.70 Hz when flux was dramatically *** source was found in the soft intermediate state during these *** further studied the energy dependence of the *** found that QPO was observed only for a higher energy range implying that the origin of QPO is possibly due to the corona emitting higher energy photons by the inverse Compton *** variation of spectral parameters can be explained with the disk truncation *** fractional rms was found to be monotonically increased with *** phase lag spectrum followed the“U-shaped”*** rms and phase lag spectrum are modeled and explained with the single-component Comptonization model vkompthdk.

关键词： X-rays binaries-accretion-accretion disks-X-rays individual (Swift J1728.9-3613)

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Communications in Theoretical Physics 2014年第1期61卷 121-126页

作者： Mukesh kumar raj kumar Department of Mathematics Motilal Nehru National Institute of Technology Allahabad

In the present work, the new exact solutions of the Boiti-Leon-Pempinelli system have been found. The system has extensive physical background. The exact solutions of the Boiti-Leon-Pempinelli system are investigated using similarity transformation method via Lie group theory. Lie symmetry generators are used for constructing similarity variables for the given system of partial differential equations, which lead to the new system of partial differentiaJ equations with one variable less at each step and eventually to a system of ordinary differential equations （ODEs）. Finally, these ODEs are solved exactly. The exact solutions are obtained under some parametric restrictions. The elastic behavior of the soliton solutions is shown graphically by taking some appropriate choices of the arbitrary functions involved in the solutions.

关键词： Boiti-Leon-Pempinelli system similarity transformation method Lie group theory soliton solutions

Steroid hormone receptors and prostate cancer： role of structural dynamics in therapeutic targeting

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Asian Journal of Andrology 2016年第5期18卷 682-686页

作者： raj kumar Department of Basic Sciences The Commonwealth Medical College Scranton PA USA.

Steroid hormone receptors （SHRs） act in cell type- and gene-specific manner through interactions with coregulatory proteins to regulate numerous physiological and pathological processes at the level of gene regulation. Binding of steroid receptor modulator （SRM） ligand leads to allosteric changes in SHR to exert positive or negative effects on the expression of target genes. Due, in part, to the fact that current SRMs generally target ligand binding domain （LBD）/AF2 and neglect intrinsically disordered （ID） N-terminal domain （NTD）/AF1, clinically relevant SRMs lack selectivity and are also prone to the development of resistance over time. Therefore, to maximize the efficacy of SHR-based therapeutics, the possibility of developing unique modulators that act to control AF1 activity must be considered. Recent studies targeting androgen receptor＇s （AR＇s） ID AF1 domain for the castration-resistant prostate cancer has provided the possibility of therapeutically targeting ID NTD/AF1 surfaces by allosteric modulations to achieve desired effects. In this review article, we discuss how inter- and intra- molecular allosteric regulations controlled by AR＇s structural flexibility and dynamics particularly the ID NTD/AF1 is an emerging area of investigation, which could be exploited for drug development and therapeutic targeting of prostate cancer.

关键词： allosteric regulation coregulatory proteins endocrine cancers intrinsically disordered proteins steroid hormone receptors structural dynamics transactivation activity

Effect of cooling media on bead geometry,microstructure,and mechanical properties of wire arc additive manufactured IN718 alloy

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Advances in Manufacturing 2024年第1期12卷 124-149页

作者： Parveen kumar Satish kumar Sharma Ratnesh kumar raj Singh Department of Mechanical Engineering Thapar Institute of Engineering and TechnologyPatialaPunjab147004India

This work aims to present and explore thermal management techniques for the wire arc additive manufacturing(WAAM)of IN718 *** heat can be mitigated via air or water *** this study,the material was deposited under four different heat-input conditions with air or water *** air cooling,the layer is deposited in a normal atmospheric air environment,whereas with water cooling,the material is deposited inside a water tank by varying the water *** validate the air and water cooling thermal management techniques,IN718 single-pass and multilayer linear walls were deposited using the bidirectional gas metal arc welding based WAAM setup under four different heat input *** the deposition of single layers,the temperature profiles were recorded,and the geometric and microstructural features were *** multilayer wall structures,the mechanical properties(hardness,tensile strength,and elongation)were determined and assessed using the corresponding microstructural features explored through scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),and electron backscatter diffraction(EBSD)*** microstructure observed through SEM analysis in the building direction was found to be nonhomogenous compared with that in the deposition ***,water cooling was found to govern bead characteristics,such as wall width and *** grain size and anisotropy of the mechanical properties also decreased in the water-cooled ***,water cooling is an economical and efficient method to mitigate excessive heat accumulation in WAAM-deposited IN718.

关键词： Air cooling Water cooling IN718 Bead characteristics Microstructure Electron backscatter diffraction(EBSD)

Invariance analysis for determining the closed-form solutions, optimal system, and various wave profiles for a (2+1)-dimensional weakly coupled B-Type Kadomtsev-Petviashvili equations

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Journal of Ocean Engineering and Science 2023年第2期8卷 133-144页

作者： Setu Rani Sachin kumar raj kumar Department of Mathematics Faculty of Mathematical SciencesUniversity of DelhiDelhi 110007India Department of Mathematics Kirori Mal CollegeUniversity of DelhiDelhi 110007India

In the case of negligible viscosity and surface tension,the B-KP equation shows the evolution of quasione-dimensional shallow-water waves,and it is growingly used in ocean physics,marine engineering,plasma physics,optical fibers,surface and internal oceanic waves,Bose-Einstein condensation,ferromagnetics,and string *** to their importance and applications,many features and characteristics have been *** this work,we attempt to perform Lie symmetry reductions and closed-form solutions to the weakly coupled B-Type Kadomtsev-Petviashvili equation using the Lie classical ***,an optimal system based on one-dimensional subalgebras is constructed,and then all possible geometric vector yields are *** can reduce system order by employing the one-dimensional optimal ***,similarity reductions and exact solutions of the reduced equations,which include arbitrary independent functional parameters,have been *** newly established solutions can enhance our understanding of different nonlinear wave phenomena and *** threedimensional and two-dimensional graphical representations are used to determine the visual impact of the produced solutions with determined parameters to demonstrate their dynamical wave profiles for various examples of Lie *** new solitary waves,kink waves,multiple solitons,stripe soliton,and singular waveforms,as well as their propagation,have been demonstrated for the weakly coupled B-Type Kadomtsev-Petviashvili *** classical method is thus a powerful,robust,and fundamental scientific tool for dealing with *** simulations are also used to prove the effectiveness of the proposed approach.

关键词： Group-invariant solutions Solitary wave solutions Lie group theory Dynamical wave structures

Bianchi .Type-I Massive String Magnetized Barotropic Perfect Fluid Cosmological Model in General Relativity

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Chinese Physics Letters 2007年第8期24卷 2455-2458页

作者： BALI raj PAREEK Umesh kumar PRADHAN Anirudh Department of Mathematics University of Rajasthan Jaipur-302 004 India Department of Mathematics Jaipur Engineering College and Research Centre Jaipur-303 905 India Department of Mathematics Hindu Post-graduate College Zamania-232 331 Chazipur India

Bianchi type-I massive string cosmological model with magnetic field of barotropic perfect fluid distribution through the techniques used by Latelier and Stachel is investigated. To obtain the deterministic model of the universe, it is assumed that the universe is filled with barotropic perfect fluid distribution. The magnetic field is due to electric current produced Mong the x-axis with infinite electrical conduictivity. The behaviour of the model in the presence and absence of magnetic field together with other physical aspects is further discussed.

关键词： coated conductor buffer layer self-epitaxy CeO2

Wide-Angle Scanning Antennas for Millimeter-Wave 5G Applications

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Engineering 2022年第4期8卷 60-71页

作者： raj Mittra Abdelkhalek Nasri Ravi kumar Arya Electrical and Computer Engineering University of Central FloridaOrlandoFL 32816USA Electrical and Computer Engineering Department Faculty of EngineeringKing Abdulaziz UniversityJeddah 21589Saudi Arabia Department of Electronics and Communication Engineering National Institute of Technology DelhiDelhi 110040India

The fifth generation(5G)network communication systems operate in the millimeter waves and are expected to provide a much higher data rate in the multi-gigabit range,which is impossible to achieve using current wireless services,including the sub-6 GHz *** this work,we briefly review several existing designs of millimeter-wave phased arrays for 5G applications,beginning with the low-profile antenna array designs that either are fixed beam or scan the beam only in one *** then move on to array systems that offer two-dimensional(2D)scan capability,which is highly desirable for a majority of 5G ***,in the main body of the paper,we discuss two different strategies for designing scanning arrays,both of which circumvent the use of conventional phase shifters to achieve beam *** note that it is highly desirable to search for alternatives to conventional phase shifters in the millimeter-wave range because legacy phase shifters are both lossy and costly;furthermore,alternatives such as active phase shifters,which include radio frequency amplifiers,are both expensive and *** this backdrop,we propose two different antenna systems with potential for the desired 2D scan performance in the millimeter-wave *** first of these is a Luneburg lens,which is excited either by a 2D waveguide array or by a microstrip patch antenna array to realize 2D scan ***,for second design,we turn to phased-array designs in which the conventional phase shifter is replaced by switchable PIN diodes or varactor diodes,inserted between radiating slots in a waveguide to provide the desired phase shifts for ***,we discuss several approaches to enhance the gain of the array by modifying the conventional array *** describe novel techniques for realizing both one-dimensional(1D)and 2D scans by using a reconfigurable metasurface type of panels.

关键词： Luneburg lens Scanning arrays Millimeter-wave antennas Switchable phase shifters Reconfigurable metasurfaces

Novel design and composition optimization of self-lubricating functionally graded cemented tungsten carbide cutting tool material for dry machining

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Advances in Manufacturing 2021年第1期9卷 34-46页

作者： Rityuj Singh Parihar raj kumar Sahu Srinivasu Gangi Setti Department of Mechanical Engineering National Institute of Technology RaipurRaipurIndia

The functionally graded cemented tungsten carbide (FGCC) is a suitable material choice for cutting tool applications due to balanced hardness and fracture *** presence of cobalt and CaF2 composition gradient in FGCC may enhance mechanical as well as antifriction ***,structural design of selflubricating FGCC was proposed using Power law composition gradient model and thermal residual stresses (TRSs) as a key ***,*** and *** model was adopted for estimation of TRS,and optimum composition gradient was identified at Power law exponent n =*** designed material displayed compressive and tensile TRS at surface and core respectively;subsequently fabricated by spark plasma sintering and characterized via scanning electron microscope (SEM),indentation *** agreement between experimental and analytical values of TRS demonstrated the effectiveness of intended design model in the composition optimization of self-lubricating *** work will be helpful in implementation of dry machining for clean and green manufacturing.

关键词： Functionally graded cemented tungsten carbide(FGCC) Thermal residual stress(TRS) Solid lubricant Power law

Dynamics of some new solutions to the coupled DSW equations traveling horizontally on the seabed

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Journal of Ocean Engineering and Science 2024年第2期9卷 154-163页

作者： raj kumar Ravi Shankar Verma Department of Mathematics Faculty of Engineering&TechnologyVeer Bahadur Singh Purvanchal UniversityJaunpur 222003India

The system of(1+1)-coupled Drinfel’d-Sokolov-Wilson equations describes the surface gravity waves travelling horizontally on the *** objective of the present research is to construct a new variety of analytical solutions for the *** invariants are derived with the aid of Killing form by using the optimal algebra classification via Lie symmetry *** invariant solutions involve time,space variables,and arbitrary *** adequate constraints on arbitrary constants,solutions are represented graphically to make them more applicable in designing sea *** behavior of solutions shows asymptotic,bell-shaped,bright and dark soliton,bright soliton,parabolic,bright and kink,kink,and periodic *** constructed results are novel as the reported results[26,28,29,30,33,38,42,49]can be deduced from the results derived in this *** remaining solutions derived in this study,are absolutely different from the earlier *** this study,the physical character of analytical solutions of the system could aid coastal engineers in creating models of beaches and ports.

关键词： Coupled Drinfel’d-Sokolov-Wilson model Invariants Killing form Optimal sub algebra Lie symmetry reductions