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Nonlinear Coupling of Kinetic Alfvén Waves and Ion Acoustic Waves in the Inner Heliosphere

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Research in Astronomy and Astrophysics 2024年第10期24卷 141-158页

作者： Mani K.Chettri Vivek Shrivastav Rupak Mukherjee Nidhi Gaur R.p.Sharma Hemam d.singh department of physics Sikkim UniversityGangtokSikkimIndia dAV public School Sector 14GurugramHaryanaIndia plasma Simulation Laboratory Department of Energy Science and EngineeringIndian Institute of Technology DelhiDelhiIndia

We study the nonlinear coupling of kinetic Alfvén waves with ion acoustic waves applicable to the Earth’s radiation belt and near-Sun streamer belt solar wind using dynamical equations in the form of modified Zakharov *** simulations show the formation of magnetic field filamentary structures associated with density humps and dips which become turbulent at later times,redistributing the energy to higher *** magnetic power spectra exhibit an inertial range Kolmogorov-like spectral index value of-5/3 for k_(⊥)ρ_(i)d by a steeper dissipation range spectra with indices~-3 for the radiation belt case and~-4 for the nearSun streamer belt solar wind case,here k_(⊥)andρ_(i)represent the wavevector component perpendicular to the background magnetic field and the ion thermal gyroradius,*** quasilinear theory in terms of the Fokker-planck equation in the region of wavenumber turbulent spectra,we find the particle distribution function flattening in the superthermal tail population which is the signature of particle energization and plasma heating.

关键词： Sun:chromosphere Sun:corona Sun:heliosphere

Effect of Co substitution on the structural,dielectric and optical properties of KBiFe_(2)O_(5)

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International Journal of Minerals,Metallurgy and Materials 2021年第11期28卷 1861-1867页

作者： K.Chandrakanta R.Jena p.pal Md.F.Abdullah S.d.Kaushik A.K.singh department of physics and Astronomy National Institute of TechnologyRourkela-769008OdishaIndia UGC-dAE Consortium for Scientific Research Mumbai Centre R-5 ShedBARCMumbai-400085India

Cobalt(Co)-modified brownmillerite KBiFe_(2)O_(5)(KBFO;[KBiFe_(2(1−x))Co_(2x)O_(5)(x=0,0.05)])polycrystalline is synthesized following the solid-state reaction *** refinement of X-ray diffraction data confirmed the phase purity of KBFO and KBiFe_(1.9)Co_(0.1)O_(5)(KBFCO).The optical bandgap energy(Eg)of KBFO decreased from 1.59 to 1.51 eV because of Co *** decrease in bandgap can be attributed to the tilting of the Fe–O tetrahedral structure of *** observed room-temperature Raman peaks of KBFCO shifted by 3 cm^(−1) toward a lower wavenumber than that of *** shift in Raman active modes can be attributed to the change in the bond angles and bond lengths of the Fe–O tetrahedral structure and modification in response to oxygen deficiency in KBFO because of Co *** with that of KBFO,the frequency-dependent dielectric constant and dielectric loss of KBFCO decrease at room temperature,which is a consequence of the reduction in oxygen migration and modification in response to vibrational modes present in the sample.

关键词： brownmillerite rietveld refinement Raman spectroscopy bandgap

Effect of URM infills on seismic vulnerability of Indian code designed RC frame buildings

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Earthquake Engineering and Engineering Vibration 2012年第2期11卷 233-241页

作者： putul Haldar Yogendra singh d.K.paul department of Earthquake Engineering IIT RoorkeeRoorkee-247667India

Unreinforced Masonry (URM) is the most common partitioning material in framed buildings in India and many other countries. Although it is well-known that under lateral loading the behavior and modes of failure of the frame buildings change significantly due to infill-frame interaction, the general design practice is to treat infills as nonstructural elements and their stiffness, strength and interaction with the frame is often ignored, primarily because of difficulties in simulation and lack of modeling guidelines in design codes. The Indian Standard, like many other national codes, does not provide explicit insight into the anticipated performance and associated vulnerability of infilled frames. This paper presents an analytical study on the seismic performance and fragility analysis of Indian code-designed RC frame buildings with and without URM infills. Infills are modeled as diagonal struts as per ASCE 41 guidelines and various modes of failure are considered. HAZUS methodology along with nonlinear static analysis is used to compare the seismic vulnerability of bare and infilled frames. The comparative study suggests that URM infills result in a significant increase in the seismic vulnerability of RC frames and their effect needs to be properly incorporated in design codes.

关键词： URM infill RC frame building Indian seismic design code seismic performance seismic vulnerability

Enhancement of Second- and Third-Order Nonlinear Optical Susceptibilities in Magnetized Semiconductors

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Chinese physics Letters 2008年第9期25卷 3276-3279页

作者： M. singh p. Aghamkar S. duhan department of Applied Sciences P.D.M. College of Engineering Bahadurgarh-124507 India department of Applied physics G.J. University of Science and Technology Hisar-125001 India department of physics Chaudhary Devi Lal University Sirsa-125055 India

Using electromagnetic treatment, an expression of effective nonlinear optical susceptibility χe [= χe^（2）＋ χe^（3） E] is obtained for Ⅲ-Ⅴ semiconducting crystals in an applied transverse dc magnetic fieM under off-resonant transition regime. The origin of nonlinear interaction lies in nonlinear polarization arising from the crystal properties such as piezoelectricity and electrostriction. Numerical estimates have been made by a representative n-InSb crystal at 77K duly irradiated by a pulsed 10.6-μm CO2 laser under off-resonant transition regime. Efforts are dedicated to optimizing doping level and externally applied dc magnetic field to achieve maximum χe^（2） and χ3^（3）. The results are found to be in good agreement with the available literature. The analysis shows that χe^（2） and χe^（3） can be significantly enhanced in doped Ⅲ-Ⅴ semiconductors by the proper selection of doping concentration and dc magnetic field, which confirms its potential as a candidate material for the fabrication of nonlinear optical devices.

关键词： the power-law exponents precipitation durative abrupt precipitation change

Structural and optical properties of green emitting Y_(2)SiO_(5):Tb^(3+) and Gd_(2)SiO_(5):Tb^(3+) nanoparticles for modern lighting applications

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Rare Metals 2021年第11期40卷 3289-3298页

作者： Sitender singh devender singh department of Chemistry Maharshi Dayanand UniversityRohtak 124001India

The optical and structural properties of Tb^(3+)-doped yttrium and gadolinium oxyorthosilicate(Y_(2)SiO_(5) and Gd_(2)SiO_(5)) phosphors were *** samples were synthesized via sol-gel combustion method using organic *** phase purity and structural properties of the samples were determined via combined approach of powder X-ray diffraction,Fourier transformation infrared(FTIR) and transmission electron microscopy(TEM).X-ray measurements revel monoclinic crystal lattice with p_(21/c) symmetry for both M_(2)SiO_(5)(pure host) and M_(2)SiO_(5):Tb^(3+)(doped) silicates,irrespective of the nature of metal(Y or Gd),presence or absence of Tb^(3+)in lattice and change in calcination temperature up to 1050℃.FTIR analysis was applied to confirm the bonding of prepared *** appearance of bands corresponding to SiO_(4) tetrahedra(880-1020 cm^(-1)) suggest the layered structure and support the diffraction *** micrographs confirm the synthesis of spherical nanoparticles with filled morphology,narrow size distribution and slightly agglomerated crystallites of the *** elemental composition of prepared materials was determined using energy dispersive X-ray *** spectra show peaks only for elements assimilated within the host *** photoluminescence(pL) emission spectra of Tb^(3+)-doped samples show ^(5)d_(4)→^(7)F_(J)(J=3-6) transitions under 254 *** dominant peak at 544 nm for ^(5)d_(4)→^(7)F_(5) transition is responsible for the emission of green light on ultraviolet-visible excitation in both the Tb^(3+)-doped host *** to advantageous properties like intense pL and high crystallinity,these nanophosphors could possess potential applications in the mercury free lighting sources and optoelectronic devices.

关键词： Structural Optical Silicates Luminescence Optoelectronic

promising drug targets and associated therapeutic interventions in parkinson's disease

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Neural Regeneration Research 2021年第9期16卷 1730-1739页

作者： Sachchida Nand Rai payal singh Ritu Varshney Vivek K.Chaturvedi Emanuel Vamanu M.p.singh Brijesh Kumar singh Centre of Biotechnology University of AllahabadPrayagrajIndia department of Zoology Institute of ScienceBanaras Hindu UniversityVaranasiIndia department of Bioengineering and Chemistry Indian Institute of Technology GandhinagarPalajGujaratIndia Faculty of Biotechnology University of Agronomic Science and Veterinary MedicineBucharestRomania department of pathology and Cell Biology Columbia University Medical CenterNew YorkNYUSA

parkinson's disease(pd) is one of the most debilitating brain diseases. despite the availability of symptomatic treatments, response towards the health of pd patients remains scarce. To fulfil the medical needs of the pd patients, an efficacious and etiological treatment is required. In this review, we have compiled the information covering limitations of current therapeutic options in pd, novel drug targets for pd, and finally, the role of some critical beneficial natural products to control the progression of pd.

关键词： dopamine epigenetics gene therapies glutamate receptor levodopa molecular chaperones monoamine oxidase B mucuna alpha-synuclein parkinson's disease striatum substantia nigra

Hepatoprotective potential of ethanolic extract of Ziziphus oenoplia(L.)Mill roots against antitubercular drugs induced hepatotoxicity in experimental models

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Asian pacific Journal of Tropical Medicine 2012年第4期5卷 283-288页

作者： Ch V Rao AKS Rawat Anil p singh Arpita singh Neeraj Verma pharmacognosy and Ethnopharmacology division National Botanical Research Institute(Council of Scientific and Industrial Research)Rana Pratap MargP.O.Box No.436Lucknow 226001Uttar PradeshIndia department of pharmacology Goel Institute of Pharmacy & SciencesFaizabad Road(Near Indira Canal) Lucknow 227105Uttar PradeshIndia

Objective:To evaluate the hepatoprotective potential of ethanolic(50%) extract of Ziziphus oenoplia(L.) Mill(***) root against isoniazid(INH) and rifampicin(RIF) induced liver damage in animal ***:Five groups of six rats each were selected for the *** extract at a dose of 150 and 300 mg/kg as well as silymarin(100 mg/kg) were administered orally once daily for 21 d in INH + RIF treated *** serum levels of glutamic oxaloacetic transaminase(SGOT),glutamate pyruvate transaminase(SGpT),alkaline phosphatase (SALp),and bilirubin were estimated along with activities of superoxide dismutase,catalase, glutathione S-transferase,glutathione peroxidase,and hepatic melondialdehyde formation. Histopathological analysis was carried out to assess injury to the ***:The considerably elevated serum enzymatic activities of glutamic oxaloacetic transaminase,glutamate pyruvate transaminase,alkaline phosphatase and bilirubin due to INH + RIF treatment were restored towards norma) in a dose dependent manner after the treatment with ethanolic extract of *** ***,the decreased activities of superoxide dismutase,catalase, glutathione S-transferase and glutathione peroxidase were also restored towards normal dose *** addition,ethanolic extract also significantly prevented the elevation of hepatic melondialdehyde formation in the liver of INH + RIF intoxicated rats in a dose dependent manner. The biochemical observations were supplemented with histopathological examination of rat liver ***:The results of this study slrongly indicate that ethanolic extract of *** has a potent hepatoprotective action against INH + RIF induced hepatic damage in rats.

关键词： Ziziphus oenoplia(Rhamnaceae) Rifampicin Isoniazid Hepatotoxicity

Stability Analysis of parallel Fuzzy p + Fuzzy I + Fuzzy d Control Systems

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International Journal of Automation and computing 2013年第2期10卷 91-98页

作者： Vineet Kumar A. p. Mittal R. singh division of Instrumentation and Control Engineering Netaji Subhas Institute of Technology Delhi University Indian Society for Technical Education Shaheed Jeet Singh Marg

The study presented in this paper is in continuation with the paper published by the authors on parallel fuzzy proportional plus fuzzy integral plus fuzzy derivative （Fp ＋ FI ＋ Fd） controller. It addresses the stability analysis of parallel Fp ＋ FI ＋ Fd controller. The famous＂small gain theorem＂ is used to study the bounded-input and bounded-output （BIBO） stability of the fuzzy controller. Sufficient BIBO-stability conditions are developed for parallel Fp ＋ FI ＋ Fd controller. Fp ＋ FI ＋ Fd controller is derived from the conventional parallel proportional plus integral plus derivative （pId） controller. The parallel Fp ＋ FI ＋ Fd controller is actually a nonlinear controller with variable gains. It shows much better set-point tracking, disturbance rejection and noise suppression for nonlinear processes as compared to conventional pId controller.

关键词： proportional plus integral plus derivative (pId) fuzzy proportional plus fuzzy integral plus fuzzy derivative (Fp + FI + Fd) controller fuzzy control bounded-input and bounded-output (BIBO) stability nonlinear process.

Effects of stenoses on non-Newtonian flow of blood in blood vessels

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International Journal of Biomathematics 2015年第1期8卷 123-135页

作者： Om prakash O. d. Makinde S. p. singh Nidhi Jain devendra Kumar School of Basic and Applied Sciences Galgotias University Greater Noida Uttar Pradesh India Faculty of Military Science Stellenbosch University Private Bag X2 Saldanha 7395 South Africa department of Mathematics DEI Dayalbagh Agra Uttar Pradesh India department of Mathematics Sachdeva Institute of Technology Farah Mathura Uttar Pradesh India

In this paper, a mathematical model for steady blood flow through blood vessels with uniform cross-section in stenoses arteries has been proposed. Blood is assumed to be non- Newtonian, incompressible and homogeneous fluid. Blood in human artery is represented as Bingham plastic fluid. Expressions for flow rate, wall shear stress, and resistance to flow against stenoses size have been obtained. Obtained results indicate that stenoses size decreases the flow rate and increases the wall shear stress as well as resistance to flow.

关键词： Stenoses wall shear stress resistance to flow flow rate non-Newtonian fluid