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structural evolution-enabled BiFeO3 modulated by strontium doping with enhanced dielectric,optical and superparamagnetic properties by a modified sol-gel method

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Chinese Physics B 2023年第3期32卷 521-530页

作者： sharon v.s.veena Gopalan E Malini k.A Department of Physics vimala College Thrissur-9 KeralaIndia

Multiferroic(BFO)nanoparticles doped with strontium with the general formula Bi1-xsrx FeO3(x=0,0.3,0.5,0.7)were synthesized using a modified sol-gel auto-combustion *** structural,electrical,optical,and magnetic properties of the samples are *** structural analysis,carried out using the x-ray powder diffraction technique,shows a structural transition from rhombohedral(R-3c)to cubic(Pm-3m)for the doping amount of strontium(sr)equal to x=*** analysis of the prepared samples were carried out using scanning electron microscopy(sEM).Frequency-dependent dielectric constant and ac conductivity were *** doped samples,with improved dielectric properties,can be used to fabricate different optoelectronic *** dielectric dispersion and broad relaxation were exhibited by all the ***–Cole plots were employed as an effective tool to study the dispersion parameters,namely,the optical dielectric constant,static dielectric constant,relaxation time,and spreading *** activation energy was calculated from the relaxation peak. and Cole–Cole plots,which were found to be compatible with each *** bandgap of the samples was calculated using diffuse reflectance spectral(DRs)*** and strong photoluminescence in the IR region was observed in the samples,similar to ZnO,which was reported for the first ***-temperature and low-temperature magnetization studies point towards the superparamagnetic nature of the samples,with an improvement in magnetic properties with *** antiferromagnetic behavior of bulk.bismuth ferrite transforms to superparamagnetic in nature for both pure and sr-substituted bismuth ferrite nanoparticles due to the close dimensions of crystallite size with magnetic domains leading to the break.down of the frustrated spin cycloidal moment.

关键词： multiferroics sol-gel process x-ray spectra optical and dielectric properties

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Magnetic nanoparticles and concentrated magnetic nanofluids:synthesis,properties and some applications

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China Particuology 2007年第1期5卷 43-49页

作者： Ladislau vk.s Doina Bica Mik.ail v. Avdeev Lab Magnetic Fluids CFATR Romanian Academy-Timisoara Division Timisoara Romania National Center for Engineering of Systems with Complex Fluids Univ. Politehnica Timisoara Timisoara Romania Lab Magnetic Fluids CFATR Romanian Academy-Timisoara Division Timisoara Romania Frank.Laboratory of Neutron Physics Joint Institute for Nuclear Research Dubna Russia

This paper reviews some recent results concerning chemical synthesis of magnetic nanoparticles and preparation of various types of magnetic nanofluids. structural properties and behaviour in external magnetic field of magnetic nanofluids will be emphasized with relation to their use in leak.ge-free rotating seals and in biomedical applications.

关键词： Magnetic nanoparticle Magnetic nanofluid Rotating seal Biomedical application Chemical co-precipitation structural characterization

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A study on assessment of hydrocarbon potential of the lignite deposits of saurashtra basin, Gujarat （Western India）

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International Journal of Coal science & Technology 2017年第4期4卷 310-321页

作者： Prak.sh k. singh v. k. singh P. k. Rajak.Neeraj Mathur Coal and Organic Petrology Lab Centre of Advanced Studyin Geology Banaras Hindu University VaranasiUttar Pradesh 221005 India Centre of Excellence for Energy studies Oil India LimitedRukminigaon GS Road Guwahati Assam 781022 India

In the present inv.s.igation, Bhavnagar lignites of the saurashtra basin （Gujarat） have been studied to assess their hydrocarbon generating potential. The samples of upper as well as lower lignite seams have been studied through microscopy and subjected to various chemical analyses viz. proximate analysis, ultimate analysis and Rock.Eval Pyrolysis. These lignites have high moisture and low to moderate ash yield but are characterized by high volatile matter. Petro- graphically they comprise predominantly of huminite group maceral while liptinite and inertinite groups occur in sub- ordinated amount. Huminite is chiefly composed of detrohuminite and telohuminite. The Tma~ （av. 416.23 ~C） and huminite reflectivity （0.28%-0.30%） indicate a low degree of maturity for these lignites which is also substantiated by the T,n~~ versus hydrogen index plot. The organic matter is subjugated by k.rogen Type-III with a potential to expel hydrocarbon on liquefaction. study further reveals that the fixed hydrocarbon is several folds higher than the free hydrocarbons. Being high in reactive maceral content, a high ＇conversion＇ and good ＇oil yield＇ values for these lignites were observed. Thus, the empirically derived values match well with those obtained through the experimental values of Rock.Eval Pyrolysis and validate their hydrocarbon generating potential.

关键词： saurashtra lignite. Reactive maceral - Rock.Eval. Hydrocarbon generating potential

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Textural and depositional processes of surface sediments of k.lpak.am, southeast Coast of India

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Frontiers of Earth science 2012年第4期6卷 392-404页

作者： Usha NATEsAN k. Deepthi AL. MUTHULAk.HMI vincent A. FERRER s.v. NARAsIMHAN v.P. vENUGOPALAN Centre for Water Resources Anna University Chennai 600025 India Water and steam Chemistry Div.s.on Bhabha Atomic Research Centre Kalpakkam 603102 India

To understand the influence of human dis- turbance on the sediment processes along k.lpak.am coast, India, beach and seabed sediments at 200 m, 500 m, and 1 k. into the sea were collected monthly for one year and analyzed. Coarser material close to the tidal inlets （river） and manmade structures （sea wall） indicate the effect of these features in altering the grain size distribution from the general trend. The bivariant plots confirm the dominance of deposition under beach environment. The CM diagram （C-one percentile grain diameter, M - median） divulges that the deposition tak.s place by suspension and rolling of sediments with C 〈 1 mm. Linear discriminate function analysis for sediments at k.lpak.am indicates a shallow marine environment for all the samples collected. On the multigroup multivariant discriminant functions v1 -v2 diagram, the bulk.of the samples from k.lpak.am to Mahabalipuram fall in the field of beach deposition. These results show that rework.d sediments, submerged during the Holocene marine transgression are being deposited on present-day beaches by wav.s. currents and rivers in the study area. Though a high wave energy environment is prevailing in the study area, dominant northward sediment transport along the k.lpak.am-Mahabalipuram human interventions. Beach coast is not altered due to building activity in front of the sea wall ensures the safety of Indira Gandhi Centre for Atomic Research （IGCAR） from wave actions without causing any significant changes to the coastal environment.

关键词： beach depositional environment grain size k.lpak.am seabed sediment

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Navigation of Non-holonomic Mobile Robot Using Neuro-fuzzy Logic with Integrated safe Boundary Algorithm

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International Journal of Automation and computing 2017年第3期14卷 285-294页

作者： A. Mallik.rjuna Rao k. Ramji B.s.k. sundara siva Rao v. v.s.a C. Puneeth Department of Mechanical Engineering V R Siddhartha Engineering College Vijayawada A.P India Department of Mechanical Engineering A.U. College of Engineering Andhra University Visakhapatnam A.P India Department of Mechanical Engineering National Institute of Technology-Warangal Telangana India

In the present work. autonomous mobile robot（AMR） system is intended with basic behaviour, one is obstacle avoidance and the other is target seek.ng in various environments. The AMR is navigated using fuzzy logic, neural network.and adaptive neurofuzzy inference system（ANFIs） controller with safe boundary algorithm. In this method of target seek.ng behaviour, the obstacle avoidance at every instant improv.s.the performance of robot in navigation approach. The inputs to the controller are the signals from various sensors fixed at front face, left and right face of the AMR. The output signal from controller regulates the angular velocity of both front power wheels of the AMR. The shortest path is identified using fuzzy, neural network.and ANFIs techniques with integrated safe boundary algorithm and the predicted results are validated with experimentation. The experimental result has proven that ANFIs with safe boundary algorithm yields better performance in navigation, in particular with curved/irregular obstacles.

关键词： Robotics autonomous mobile robot(AMR) navigation fuzzy logic neural network. adaptive neuro-fuzzy inference system(ANFIs) safe boundary algorithm

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Interacting tachyonic scalar field

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Communications in Theoretical Physics 2021年第2期73卷 102-107页

作者： A k.ndu s D Pathak.v k.Ojha Department of Physies Lovely Professional UniversityPhagwaraPunjab144411India school of sciences SAGE University BhopalMadhya Pradesh462022India

We discuss the coupling between dark.energy and matter by considering a homogeneous tachyonic scalar field as a candidate for dark.*** obtained the functional form of scale factor by assuming that the coupling strength depends linearly on the Hubble parameter and energy *** also estimated the cosmic age of the Universe for different values of coupling constant.

关键词： dark.energy dark.matter scalar field achyonic scalar field

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spontaneous ethanol-water emulsification as a precursor for porous particle formation: Understanding the role of dissolved carbohydrates

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Particuology 2019年第3期17卷 44-53页

作者： P.L. Xiao s. Mansouri v. suriya Hena Y.k. Bong k. Hapgood M.W. Woo Department of Chemical Engineering Faculty of Engineering Monash University Clayton Campus Australia Powder Metallurgy Research Institute Central South University China Faculty of science Engineering &Bu ε Environment School of Engineering Deakin University Geelong Waum Ponds Campus Australia

Quiescent mixing of aqueous lactose solution with ethanol by gentle pouring allowed controlled observation of a transient, spontaneous emulsification process between ethanol and water. This phenomenon contrasts with the conventional stable phase-separation process for ethanol-water systems with other solutes. The presence of lactose in the dissolved state was deduced to be the k.y factor causing spontaneous emulsification. This explains the transitional behavior of the phenomenon. Further experiments with aqueous maltodextrin solution, using the same experimental technique, confirmed this phenomenon. The mechanisms determined in this work.will form the basis of porous-particle synthesis via the antisolvent vapor-precipitation technique.

关键词： spontaneous emulsification Ethanol Lactose Precipitation Crystals Droplets

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Performance of inclined pillars with a major discontinuity

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International Journal of Mining science and Technology 2019年第3期29卷 437-443页

作者： k.v.Jessu A.J.s.spearing Western Australia school of Mines k.lgoorlie Curtin University

Discontinuities are an inherent part of the rock.mass and majorly affect the stability of the excavation sk.n and *** dip of the discontinuities and their properties also have a significant effect on the strength of the *** approaches are commonly used to determine the pillar strength but can overestimate the strength and don’t consider the inclination of the pillars and the strength reduction caused by *** modeling is a powerful tool and if calibrated can be used to evaluate the strength of the pillars with discontinuities having a range of *** effect of a discontinuity on inclined pillars was conducted which has been seldom considered in evaluating the pillar ***-dimensional vertical pillars were simulated,and the pillar strength was calibrated to accepted theoretical results and then the discontinuities were introduced in different pillar inclinations with distinct width to height ratios to gain an insight into the effective pillar strength *** upon the results,it was found that the discontinuities have a significant effect with the increase in the inclination of the pillars even at a higher width to height ratios.

关键词： Numerical modelling Pillar Discontinuities Inclination Width to height ratios

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New Data on the Mineralogy of Chromite from the Nuggihalli schist Belt,Western Dharwar Craton,k.rnatak.,India:Petrogenetic Implications

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Acta Geologica sinica(English Edition) 2011年第1期85卷 107-115页

作者： Perumala v.s.RAJU Elapavalooru v.s.s.k.BABU Roland k.W.MERk.E National Geophysical Research Institute Hyderabad India(Council of Scientific and Industrial Research) Department of Geology University of Pretoria PretoriaSouth Africa

The occurrence of rhythmic layering of chromite and host serpentinites in the deformed layered igneous complexes has been noticed in the Nuggihalli schist belt （NsB） in the western Dharwar craton, k.rnatak., south India. For this study, the chromitite rock.samples were collected from Jambur, Tagadur, Bhak.tarhalli, Ranganbetta and Byrapur in the NsB. Petrography and ore microscopic studies on chromite show intense cataclasis and alteration to ferritchromite. The ferritchromite compositions are characterized by higher Cr number （Cr/[Cr＋AI]）（0.68-0.98） and lower Mg number （Mg/[Mg＋Fe]）（0.33-0.82） ratios in ferritchromite compared to that of parent chromite. The formation process for the ferritchromite is thought to be related to the exchange of Mg, AI, Cr, and Fe between the chromite, surrounding silicates （serpentines, chlorites）, and fluid during serpentinization.

关键词： chromite ferritchromite Nuggihalli schist belt Dharwar Craton India

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Trace element geochemistry and sr-Nd characteristics of Mesoproterozoic mafic intrusive rock. from Rondonia, Brazil, sW Amazonian Craton： Petrogenetic and tectonic inferences

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Episodes 2008年第4期31卷 392-400页

作者： Girardi, v.A. v. Teixeira, W. Bettencourt, J.s. Andrade, s. Navarro, M.s. sato, k. Instituto de Geociencias Universidade de Sao Paulo Rua do Lago 562. CEP 05508-080 Cidade Universitada S. Paulo Brazil

The Amazonian Craton comprises an Archean domain surrounded by four successively younger Proterozoic tectonic provinces. Within the Rio-Negro-Juruena province the serra da Providencia Intrusive suite （1.60 and 1.53 Ga） consists of A-type rapak.vi gran- ites, charnock.tes and mangerites genetically associated with diabase dik.s, gabbros and amphibolites. The original mafic melts were derived from a depleted mantle source （εN（T）＋2.5 to ＋2.8;εsr（T） -12.1）. Underplated mafic magma induced melting of a short-lived felsic crust, thus originating coeval felsic-mafic magmatism in a conti- nental intraplate setting. The Colorado Complex, assigned to the Rondonian-san Ignacio province, comprises 1.35-1.36 Ga intrusive bimodal magmatism represented by monzonite gneisses associated with amphibolite, gabbro and metadiabase dik.s intercalated with metasediments with detrital zircon that yield U- Pb ages of 1.35 to 1.42 Ga. Mafic samples dis- play juvenile signatures （εNd（T） 0.0 to ＋5.2; εsr（T） --5.0 to --30.7） and are less contaminated than the serra da Previdencia and Nova Brasilandia ones. The generation of the basaltic magma is related to the subduction of an oceanic slab below the peridotite wedge （intraoceanic arc setting）. Fluids and/or small melts from the slab impregnated the mantle. The Nova Brasilandia sequence （sunsas-Aguapef province） comprises a metasedimentary sequence intruded by 1.10-1.02 Ga metadia- bases, gabbros, meta-gabbros, and amphibolites associated with granitic plutons （bimodal mag- matism）. The original tholeiitic magmas, derived from a depleted source （εNd（T） = ＋3.1 to ＋5.0）, in a proto-oceanic setting, underwent subsequent contamination by the host rock., as indicated by the isotopic and trace element data.

关键词：亚马逊河流域巴西 sr-Nd特性地球化学

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