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Journey through the birth, growth and maturity of X-ray astronomy

Research in Astronomy and Astrophysics 2019年第10期19卷 1-16页

作者： prahlad chandra agrawal MU-DAE Centre of Excellence in Basic Sciences Mumbai University Campus at Vidhyanagari

In this biographical account, I recall my scientific journey that began in 1961 when I joined as a Physics Trainee in the BARC Training School and after one year course was admitted in TIFR as a Research Associate. During 1962–1967, I worked on determination of the He^3 /He^4 ratio in cosmic rays using a gas Cerenkov counter and also used a scintillation + solid Cerenkov detector to measure flux of protons and helium nuclei in primary cosmic rays. I also developed a large area scintillation-Cerenkov detector with a spark chamber between them for measuring charge composition of primary cosmic rays. I joined the X-ray astronomy programme in 1967 initiated by Prof. B. V. Sreekantan and played a leading role in developing a balloon borne hard X-ray instrument for studying time variability and energy spectra of cosmic X-ray sources. We carried out a series of balloon experiments and studied temporal intensity variation and energy spectra of X-ray objects like Sco X-1, Cyg X-1, etc. Results on rapid intensity changes and spectra appeared in a series of publications based on which I obtained a Ph.D. degree in 1972. Immediately afterwards, I joined Prof. Gordon Garmire at Caltech as a Research Fellow (a post-doctoral position) to work with him on the low energy component of HEAO A-2 experiment. The instrument was developed and successfully realised. Working on this satellite experiment was a thrilling experience which exposed me to the technical complexities of space instruments. The HEAO-1 satellite was launched in 1978. During 1978–1979, Guenter Riegler and I, working at JPL, reported detection of intense soft X-rays from several classes of extragalactic and Galactic objects like new BL Lacs, a new AM Her binary, coronal X-rays from active stars, etc. After returning to TIFR, I developed a rocket experiment with K. P. Singh to map the spatial and spectral distribution of the Soft Diffuse X-ray Background. At the same time, I also designed 15 cm deep Xenon filled Proportio

关键词： TIFR-X-ray Astronomy by balloons-rockets and satellites-Indian Astronomy Satellite ASTROSAT

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AstroSat observation of the Be/X-ray binary Pulsar 3A 0726–260(4U 0728–25)

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Research in Astronomy and Astrophysics 2020年第9期20卷 349-357页

作者： Jayashree Roy prahlad C.agrawal Baibhav Singari Ranjeev Misra UM-DAE Centre for Excellence in Basic Sciences University of MumbaiVidyanagari CampusMumbai400098MaharashtraIndia Inter-University Center for Astronomy and Astrophysics Post Bag 4Pune411007MaharashtraIndia School of Physical Sciences National Institute of Science Education and Research BhubaneswarKhurda752050OdishaIndia

Results on timing and spectral properties of the Be/X-ray binary pulsar 3A 0726-260(4U 0728-25)are *** binary was observed on 2016 May 6-7 with the Large Area X-ray Proportional Counter(LAXPC)and Soft X-ray Telescope(SXT)instruments onboard the AstroSat *** this observation,the source was in non-flaring persistent state at a flux level of^8.6±0.3×10^-11 erg cm^-2 s^-1in 0.4-20 *** X-ray pulsations with a period of 103.144±0.001 s are detected in 0.3-7 keV with the SXT and in 3-40 keV with the *** pulse profile is energy dependent,and there is an indication that the pulse shape changes from a broad single pulse to a double pulse at higher *** energies above20 keV,we report the first time detection of pulsation period 103.145±0.001 s and the double peaked pulse profile from the *** energy spectrum of the source is derived from the combined analysis of the SXT and LAXPC spectral data in 0.4-20 *** best spectral fit is obtained by a power law model with a photon index(1.7±0.03)with high energy spectral cut-off at 12.9±0.7 keV.A broad iron line at^6.3 keV is detected in the energy *** briefly discuss the implications of these results.

关键词： Be/X ray binary pulsar 4U 0728–25

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AstroSat Observations of the Be/X-Ray Binary XTE J1946+274 During 2018 and 2021 Outbursts

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Research in Astronomy and Astrophysics 2023年第4期23卷 26-43页

作者： Amar Deo chandra Jayashree Roy P.C.agrawal Indian Institute of Science Education and Research Kolkata Mohanpur 741246West BengalIndia Inter-University Center for Astronomy and Astrophysics Post Bag 4Pune 411007MaharashtraIndia Department of Astronomy and Astrophysics Tata Institute of Fundamental ResearchHomi Bhabha RoadMumbai 400005MaharashtraIndia

We present the timing and spectral studies of the Be/X-ray binary XTE J1946+274 during its 2018 and 2021 giant outbursts using observations with the SXT and LAXPC instruments on the AstroSat *** the 1998 and 2010 outbursts,where a giant outburst was followed by several low intensity periodic outbursts,the 2018 and 2021 outbursts were single *** X-ray pulsations are detected over a broad energy band covering 0.5–80 keV from the compact *** construct the spin evolution history of the pulsar over two decades and find that the pulsar spins-up during the outbursts but switches to spin-down state in the quiescent periods between the *** resolved pulse profiles generated in several bands in 0.5–80 keV show that the pulse shape varies with the *** energy spectrum of the pulsar is determined for the 2018 and 2021 *** best fit spectral models require presence of cyclotron resonant scattering feature at about 43 keV in the energy spectra of both the *** find indication of possible reversal in the correlation between the cyclotron line energy and luminosity which needs to be ascertained from future *** the best fit spectra the X-ray luminosity of XTE J1946+274 is inferred to be 2.7×10^(37) erg s^(-1) for the 2018 observations and 2.3×10^(37) erg s^(-1) for the 2021 *** discuss possible mechanisms which can drive outbursts in this transient Be X-ray binary.

关键词： accretion-accretion disks-stars neutron-(stars:)pulsars general-X-rays binaries-stars emission-line-Be-X-rays bursts

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Influence of Sputtering Gas on Morphological and Optical Properties of Magnesium Films

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Journal of Materials Science & Technology 2011年第1期27卷 51-58页

作者： Yogendra K.Gautam Amit K.Chawla Vipin Chawla R.D.agrawal Ramesh chandra Department of Metallurgical and Materials Engineering Indian Institute of Technology Roorkee Nano Science Laboratory Institute Instrumentation CentreIndian Institute of Technology Roorkee

The influence of sputtering gas（He Ar） on the structural properties of Mg thin films has been *** optical property（reflectance） that results from the growth of films at varying substrate temperatures（Tsub） was also *** deposited films were characterized by using X-ray diffraction（XRD）,field emission scaning electron microscopy（FE-SEM）,atomic force microscopy（AFM） and UV-Vis-NIR *** smaller crystallite size and lower deposition rate were observed in the presence of Helium atmosphere compared to *** of the films shows 2D hexagonal geometry of grains in the deposition temperature range（Tsub≈50-150℃） in both the sputtering *** surface roughness of the polycrystalline films were found to increase with increase in the deposition temperature of both ambient *** reflectance of Mg films was measured in near infrared region and larger reflectance was observed from Mg films sputtered in He atmosphere compared to that in argon.

关键词： X-ray diffraction(XRD) Atomic force microscopy(AFM) Reflectance Mg films Microstructure

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Characterization,spectroscopic investigation of defects by positron annihilation,and possible application of synthesized PbO nanoparticles

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Chinese Physics B 2021年第2期30卷 400-407页

作者： Sk Irsad Ali Anjan Das Apoorva agrawal Shubharaj Mukherjee Maudud Ahmed P M G Nambissan Samiran Mandal Atis chandra Mandal Department of Physics University of BurdwanGolapbagBurdwan 713104West BengalIndia Department of Physics A.P.C.Roy Government CollegeSiliguriDarjeeling 734010West BengalIndia Applied Nuclear Physics Division Saha Institute of Nuclear Physics1/AF BidhannagarKolkata 700064India Department of Physics Government General Degree College at PedongKalimpong 734311West BengalIndia

Nanocrystalline samples of highly pure lead oxide were prepared by the sol-gel route of synthesis.X-ray diffraction and transmission electron microscopic techniques confirmed the nanocrystallinity of the samples,and the average sizes of the crystallites were found within 20 nm to 35 *** nanocrystallites exhibited specific anomalous properties,among which a prominent one is the increased lattice parameters and unit cell *** optical band gaps also increased when the nanocrystallites became smaller in *** latter aspect is attributable to the onset of quantum confinement effects,as seen in a few other metal oxide *** annihilation was employed to study the vacancy type defects,which were abundant in the samples and played crucial roles in modulating their *** defect concentrations were significantly larger in the samples of smaller crystallite *** results suggested the feasibility of tailoring the properties of lead oxide nanocrystallites for technological applications,such as using lead oxide nanoparticles in batteries for better performance in discharge rate and *** also provided the physical insight into the structural build-up process when crystallites were formed with a finite number of atoms,whose distributions were governed by the site stabilization energy.

关键词： lead oxide nanocrystals positron annihilation sol-gel processes

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Understanding Brown Planthopper Resistance in Rice: Genetics, Biochemical and Molecular Breeding Approaches

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Rice science 2021年第6期28卷 532-546页

作者： Lakesh MUDULI Sukanta Kumar PRADHAN Abinash MISHRA Debendra Nath BASTIA Kailash chandra SAMAL Pawan Kumar agrawal Manasi DASH Department of Plant Breeding and Genetics College of AgricultureOdisha University ofAgriculture and TechnologyBhubaneswar 751003OdishaIndia Department of Bioinformatics Centre for Post Graduate StudiesOdisha University of Agriculture and TechnologyBhubaneswar 751003OdishaIndia Department of Agricultural Biotechnology College of AgricultureOdisha University of Agriculture and TechnologyBhubaneswar 751003OdishaIndia

Brown planthopper(BPH,Nilaparvata lugens St自I)is the most devastating pest of rice in Asia and causes significant yield loss *** 37 BPH resistance genes have been identified so far in indica,African rice varieties along with wild germplasms such as Oryza officinalis,***,***,***,*** and O,***/QTLs involved in BPH resistance,including Bph1,bph2/BPH26,Bph3,Bph6,bph7,BPH9,Bph12,Bph14,Bph15,Bph17,BPH18,bph19,Bph20,Bph21(t),Bph27,Bph27©Bph28(t),BPH29,QBph3,QBph4,QBph4.2,Bph30,Bph32,Bph33,Bph35 and Bph36,have been fine-mapped by different researchers across the *** majority of genes/QTLs are located on rice chromosomes 1,3,4,6,11 and *** plants respond to BPH attack by releasing various endogenous metabolites like proteinase inhibitors,callose,secondary metabolites(terpenes,alkaloids,flavonoid,etc.)and volatile *** that,hormonal signal pathways mediating(antagonistic/synergistic)resista nee responses in rice have been well ***-assisted breedi ng and genome editi ng techniq ues can also be adopted for improving resista nee to novel BPH biotypes.

关键词： rice brown planthopper resista nee wild germplasm marker-assisted breedi ng genome editing secondary metabolite

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Evaluating the Impact of Software Security Tactics: A Design Perspective

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Computers, Materials & Continua 2021年第3期66卷 2283-2299页

作者： Mamdouh Alenezi Abhishek Kumar Pandey Richa Verma Mohd Faizan Shalini chandra Alka agrawal Rajeev Kumar Raees Ahmad Khan College of Computer and Information Sciences Prince Sultan UniversitySaudi Arabia Department of Information Technology Babasaheb Bhimrao Ambedkar UniversityLucknowUttar PradeshIndia Department of Computer Science Babasaheb Bhimrao Ambedkar UniversityLucknowUttar PradeshIndia Department of Computer Application Shri Ramswaroop Memorial UniversityLucknowUttar PradeshIndia

Design architecture is the edifice that strengthens the functionalities as well as the security of web *** order to facilitate architectural security from the web application’s design phase itself,practitioners are now adopting the novel mechanism of security *** the intent to conduct a research from the perspective of security tactics,the present study employs a hybrid multi-criteria decision-making approach named fuzzy analytic hierarchy process-technique for order preference by similarity ideal solution(AHP-TOPSIS)method for selecting and assessing multi-criteria *** adopted methodology is a blend of fuzzy analytic hierarchy process(fuzzy AHP)and fuzzy technique for order preference by similarity ideal solution(fuzzy TOPSIS).To establish the efficacy of this methodology,the results are obtained after the evaluation have been tested on fifteen different web application projects(Online Quiz competition,Entrance Test,and others)of the Babasaheb Bhimrao Ambedkar University,Lucknow,*** tabulated outcomes demonstrate that the methodology of the Multi-Level Fuzzy Hybrid system is highly effective in providing accurate estimation for strengthening the security of web *** proposed study will help experts and developers in developing and managing security from any web application design phase for better accuracy and higher security.

关键词： Web application software security security tactics fuzzy AHP fuzzy TOPSIS

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Mg2＋-ion Conducting Polymer Electrolytes： Materials Characterization and All-Solid-State Battery Performance Studies

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Journal of Physical Science and Application 2013年第1期3卷 9-17页

作者： Rakesh chandra agrawal Dinesh Kumar Sahu Solid State lonics Research Laboratory SOS in Physics and Astrophysics Pt. Ravishankar Shukla University Raipur 492010India Rungta Engineering College Raipur 492001 India

For All-Solid-State battery applications, Mg2＋-ion conducting polymer electrolytes and Mg-metal electrode are currently considered as alternate choices in place of Li＋-ion conducting polymer electrolytes/Li-metal electrode. Present paper reports fabrication of All-Solid-State battery based on the following Mg2＋-ion conducting nano composite polymer electrolyte （NCPE） films： [85PEO： 15Mg（C104）2] ＋ 5% TiO2 （〈 100 nm）, [85PEO： 15Mg（CIO4）2] ＋ 3% SiO2（-8 nm）. [85PEO： 15Mg（CIO4）2] ＋ 3% MgO （〈 100 nm）, [85PEO：15Mg（C1O4）2] ＋ 3% MgO （-44 μm）. NCPE films were prepared by hot-press technique. Solid Polymer Electrolyte （SPE） composition： [85PEO： 15Mg（CIO4）2], identified as high conducting film at room temperature, has been used as ISt--phase host and nano/micro particles of active （MgO）/passive （SiO2, TiO2） fillers as IInd-phase dispersoid. Filler particle dependent conductivity studies identified above mentioned NCPE films as optimum conducting composition （OCC） at room temperature. Ion transport behavior of SPE/NCPE film materials was investigated previously. Present paper reports materials characterization and cell performance studies on All-Solid-State batteries： Mg （Anode） Ⅱ SPE or NCPE films tt C＋MnO2＋Electrolyte （Cathode）. Open circuit voltage （OCV） obtained was in the range： 1.79-1.92 V. The batteries were discharged at room temperature under different load conditions and some important battery parameters have been evaluated from plateau region of cell-potential discharge profiles. All the batteries performed quite satisfactorily specially under low current drain states.

关键词： Solid polymer electrolyte (SPE) nano composite polymer electrolyte (NCPE) hot-press technique all-solid-state batteries.

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