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Journal of Materials science & Technology 2021年第23期82卷 214-226页

作者： G.Karthick Lavanya Raman b.s.murty Department of Metallurgical and Materials Engineering Indian Institute of Technology MadrasChennai600036India Indian Institute of Technology Hyderabad Kandi502285India

High entropy pyrochlores(HEP)are potential candidates as dispersoids in the oxide dispersed strengthened steels or alloys,which can be used in nuclear reactors and supercritical *** the first time,HEP oxides Y_(2)(TiZrHfMoV)_(2)O_(7) were synthesized with Y_(2)Ti_(2)O_(7) as a base structure with the b site(Ti)substituted with five cations through reverse co-precipitation technique in the nanocrystalline form at lowest synthesis *** synthesis parameters for Y_(2)(TiZrHfMoV)_(2)O_(7)(5C)and other derived compositions(five compositions of four cationic systems with each cation eliminated at b site from 5 C)are optimised to obtain lower crystallite and particle sizes.5C has a smaller crystallite size(27 nm)than other single-phase *** cation’s influence,oxidation state,and oxygen vacancy in the phase formation were analysed through *** single-phase HEPs are consolidated through spark plasma sintering.Y_(2)(TiZrHfMo)_(2)O_(7)(4 C-V)shows the highest hardness among the compositions reported so far due to its finer grain size,and Y_(2)(TiHfMoV)_(2)O_(7)(4 C-Zr)has a higher Young’s modulus compared to other single-phase composition due to its higher degree of order in the structure.

关键词： High entropy pyrochlores Reverse co-precipitation b site substitution Hardness Young’s modulus

Effect of grain size on dielectric and ferroelectric properties of nanostructured ba_0.8)sr_(0.2)TiO_(3) ceramics

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Journal of Advanced Ceramics 2015年第1期4卷 46-53页

作者： Venkata Ramana MUDINEPALLI Leng FENG Wen-Chin LIN b.s.murty Department of Physics “National Taiwan Normal University”Taipei 11677TaiwanChina Department of Chemistry Shenzhen Graduate SchoolPeking UniversityShenzhen 518055China Nanotechnology Laboratory Department of Metallurgical and Materials EngineeringIndian Institute of Technology-MadrasChennai 600036India

barium strontium titanate( ba_0.8)sr_(0.2)TiO_(3),bsT)nanocrystalline ceramics have been synthesized by high energy ball *** the sintering temperature increases from 1200℃to 1350℃,the average grain size of bsT ceramics increases from 86 nm to 123 *** X-ray diffraction(XRD)studies show that these ceramics are *** phase and grain size of the sintered pellets have been estimated from the XRD patterns,scanning electron microscopy(sEM)and transmission electron microscopy(TEM)*** effect of grain size on dielectric and ferroelectric properties is *** dielectric and piezoelectric parameters are greatly improved at room temperature with increase in grain *** Curie transition temperature is found to shift slightly towards higher temperatures as the grain increases from 86 nm to 123 *** coercive field decreases and the remnant polarization and spontaneous polarization increase as the grain size of bsT nano ceramics *** ceramics are promising materials for tunable capacitor device applications.

关键词： nanocrystalline ceramics lead free ceramics crystallization electron microscopy dielectric properties hysteresis

Mechanical properties of Ni_(0.83)Co_(0.15)Cu_(0.02)Fe_(1.9)O_(4-δ)+PbZr_(0.52)Ti_(0.48)O_(3)particulate composites by composite oscillator technique and the correlation with the results of magnetoelectric properties

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Journal of Advanced Ceramics 2012年第4期1卷 317-326页

作者： M.Venkata RAMANA M.Penchal REDDY N.Ramamanohar REDDY b.s.murty K.V.sIVA KUMAR shenhua sONG shenzhen Key Laboratory of Advanced Materials Department of Materials Science and EngineeringShenzhen Graduate SchoolHarbin Institute of TechnologyShenzhen 518055China Department of Physics Changwon National UniversityChangwonRepublic of Korea Ceramic Composite Materials Laboratory Department of PhysicsSri Krishnadevaraya UniversityAnantapur 515003India Nanotechnology Laboratory Department of Metallurgical and Materials EngineeringIndian Institute of TechnologyChennai 600036India

The xNi_(0.83)Co_(0.15)Cu_(0.02)Fe_(1.9)O_(4-δ)+PbZr_(0.52)Ti_(0.48)O_(3)(PZT)particulate magneto ferroelectric composites with x=0,0.1,0.2,0.3,0.4,0.5 and 0.6 mole fraction were prepared by conventional ceramic double sintering *** presence of two phases(perovskite structure of ferroelectric phase and spinal structure of ferromagnetic phase)was confirmed by X-ray *** magnetoelectric(ME)property of the particulate composites was determined at room temperature as a function of intensity of magnetic *** temperature variation of the longitudinal modulus(L)and the internal friction(Q−1)of these particulate composites at 104.3 kHz was studied in the wide temperature range 30-420℃.The temperature variation of the longitudinal modulus in each composition of these particulate composites showed two abrupt *** minimum coincided with the ferroelectric-paraelectric Curie transition temperature(θE)and the other with the ferromagnetic-paramagnetic Curie transition temperature(θM).The internal friction measurement also showed two sharp peaks in each composition corresponding to those temperatures where the minima were noticed in the temperature variation of the longitudinal modulus behaviour.

关键词： X-ray diffraction magnetoelectric effect piezoelectric coefficient internal friction Curie transition temperature

sYNTHEsIs OF LEAD FREE sODIUM bIsMUTH TITANATE(NbT)CERAMIC bY CONVENTIONAL AND MICROWAVE sINTERING METHODs

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Journal of Advanced Dielectrics 2011年第1期1卷 71-77页

作者： M.VENKATA RAMANA s.ROOPAs KIRAN N.RAMAMANOHAR REDDY K.V.sIVA KUMAR V.R.K.MURTHY b.s.murty Ceramic Composite Materials Laboratory Department of Physics Sri Krishnadevaraya UniversityAnantapur 515003India Microwave Laboratory Department of Physics Indian Institute of Technology Chennai 600036India Nanotechnology Laboratory Department of Metallurgical and Materials Engineering Indian Institute of Technology Chennai 600036 India

Dielectric studies were carried out on a lead free sodium bismuth Titanate,NbT,(Na_(0.5)bi_(0.5)TiO_(3))*** material was synthesized by conventional ceramic method(Cs)and microwave sintering(Ms).The presence of single phase has been confirmed by X-ray diffraction and scanning electron microscopy of NbT *** later technique(Ms)resulted in material with high density,dielectric properties and improved *** transition temperature was observed slightly higher for microwave sintered(Ms)*** modulus measurements are very sensitive property to identify the phase transitions in *** modulus(L)measurements were also employed on these samples in the frequency 136 kHz and can be studied in the wide temperature range 30℃to 400℃.The elastic behavior(L)showed a break at two temperatures(~200℃and 350℃)in both the conventional and microwave sintered *** NbT ceramics,permittivity anomalies are connected to modulus *** results are correlated with the dielectric *** behavior explained in the light of structural phase transitions in the ferroelectric ceramics.

关键词： Microwave sintering NbT X-ray diffractometer scanning electron microscopy dielectric properties longitudinal modulus

Microstructure, properties and hot workability of M300 grade maraging steel

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Defence Technology（防务技术） 2018年第1期14卷 51-58页

作者： K.V.A.Chakravarthi N.T.b.N.Koundinya s.V.s.Narayana murty b.Nageswara Rao Materials and Mechanical Entity Vikram Sarabhai Space Centre Research scholar Department of Mechanical Engineering K L University Department of Metallurgical Engineering and Materials science Indian Institute of Technology Department of Mechanical Engineering K L University

This paper presents isothermal uniaxial compression test results of M300 grade maraging steel over a wide range of temperatures(900 e1200℃) and strain rates(0.001 e100 s^(-1)) to examine hot deformability and concurrent microstructural evolution. Processing map is generated and indicated the optimum processing parameters in the temperature range of 1125℃-1200℃ and strain rate range of 0.001 e0.1 s^(-1). High values of the efficiency of power dissipation, microstructural observations and EbsD results indicate softening mechanism to be the occurrence of dynamic recrystallisation. Material constants in a constitutive relation are evaluated from the flow stress data useful in computer modelling.

关键词： Activation energy Constitutive relation Hot deformation M300 grade maraging steel Processing map

Neuroinflammation revisited through the microglial lens

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Neural Regeneration Research 2025年第7期20卷 1989-1990页

作者： Renato socodato João b.Relvas Institute of Research and Innovation in Health(i3s)and Institute for Molecular and Cell biology(IbMC) University of PortoPortoPortugal Department of biomedicine Faculty of Medicine of the University of Porto(FMUP)PortoPortugal

Neuroimmunology is emerging as a pivotal field,shedding light on the intricate dialogues between the central nervous system(CNs)and the immune *** exploration is particularly significant in understanding microglia,the CNs’s innate immune cells,beyond the conventional conflation of“neuroinflammation”and“microglial activation.”This conflation has clouded the true complexity of these processes,potentially stalling scientific progress and the development of new *** challenge the long-standing perspectives that have oversimplified these interactions,advocating for a deeper exploration of the dynamic relationship between neuroinflammation and microglial *** dissecting specific molecular pathways,we aim to illuminate their elaborate roles in neuroinflammatory responses,especially in the context of Alzheimer’s disease(AD).Here,neuroinflammation is not merely a passive observer or a direct antagonist but a complex agent in the disease’s *** article calls for a significant paradigm shift towards an integrative,multi-omics approach to *** such a comprehensive framework is crucial for advancing our understanding of neuroinflammatory conditions and paving the way for targeted therapeutic strategies for brain diseases.

关键词： inflammation simplified activation

Effects of caliber rolling on microstructure and room temperature tensile properties of Mge3Ale1Zn alloy

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Journal of Magnesium and Alloys 2013年第2期1卷 169-175页

作者： R.L.Doiphode s.V.s.Narayana murty N.Prabhu b.P.Kashyap Department of Metallurgical Engineering and Materials science Indian Institute of Technology BombayMumbai 400076India special Materials Division Vikram Sarabhai Space CenterISROTrivandrum 695022India

Mge3Ale1Zn(AZ31)alloy was caliber rolled isothermally in the temperature range of 250e450C to develop fine grains of 3.6e12.5 *** stressestrain curves obtained from tensile tests at room temperature were found to vary with the temperature employed in caliber *** tensile strength of 290 MPa and ductility of 13.5%were obtained upon caliber rolling at 300C as compared to 188 MPa and 15.2%,respectively,in the mill-rolled *** variations in tensile properties are explained by the concomitant grain size,texture and twins obtained as a function of caliber rolling temperature.

关键词： AZ31 Mg-alloy Caliber rolling Twinning Grain size Tensile properties

Grain growth in calibre rolled Mg-3Al-1Zn alloy and its effect on hardness

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Journal of Magnesium and Alloys 2015年第4期3卷 322-329页

作者： R.L.Doiphode s.V.s.Narayana murty N.Prabhu b.P.Kashyap Department of Metallurgical Engineering and Materials science Indian Institute of Technology BombayMumbai 400076India Department of Mechanical Engineering Government PolytechnicKolhapur 416004India special Materials Division Vikram Sarabhai Space CenterISROTrivandrum 695022India

Calibre rolling of Mg-3Al-1Zn alloy at 300℃ led to development of fine grain size of 3μ*** annealing,from 5 to 6000 minutes at 300-450℃,revealed faster grain growth initially up to 60 minutes,which became sluggish on prolonged *** time exponent for grain growth kinetics(n)suggests bi-linear behaviour with n=0.11 and 0.008 over these time *** activation energy,based on various n values,varied over wide ranges that made the understanding of the mechanisms for grain growth *** problem is explained by concurrent evolution of texture and grain boundary *** effect of grain growth on hardness at ambient temperature was found to follow the H-P type relationship.

关键词： Annealing AZ31 Mg-alloy Calibre rolling Twinning Grain growth

brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

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Neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs Víctor Cilleros-Mañé Laia Just-borràs Marta balanyà-segura Aleksandra Polishchuk Laura Nadal Marta Tomàs Carolina silvera-simón Manel M.santafé Maria A.Lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase b receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and C(PKA and PKC)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated Trkb/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKC activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorb

Nonsmooth semi-Infinite Minmax Programming Involving Generalized(Φ, ρ)-Invexity

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Journal of systems science & Complexity 2015年第4期28卷 857-875页

作者： UPADHYAY b b MIsHRA s K Department of basic sciences & Humanities National Institute of Technology

This paper introduces some new generalizations of the concept of （~, p）-invexity for non- differentiable locally Lipschitz functions using the tools of Clarke subdifferential. These functions are used to derive the necessary and sufficient optimality conditions for a class of nonsmooth semi-infinite minmax programming problems, where set of restrictions are indexed in a compact set. Utilizing the sufficient optimality conditions, the authors formulate three types of dual models and establish weak and strong duality results. The results of the paper extend and unify naturally some earlier results from the literature.

关键词： Duality, generalized invexity locally Lipschitz functions, minmax programming, semi-infinite programming.