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Journal of Rare Earths 2015年第2期33卷 140-147页

作者： V.V.Rangari S.J.Dhoble department of physics RTM Nagpur University

BaGdB9O16：Eu^3＋ and Ba（Gd,Ln）B9O16：Eu^3＋（Ln=La, Y） phosphors were synthesized by solid state diffusion method. The X-ray diffraction, scanning electron microscopy（SEM） and photoluminescence properties were investigated. The as-synthesized BaGdB9O16：Eu^3＋ and Ba（Gd,Ln）B9O16：Eu^3＋（Ln=La, Y） phosphors showed strong red emission under ultraviolet light excitation. By partially substituting Gd^3＋ by La^3＋ and Y^3＋ ions in the host BaGdB9O16：Eu^3＋ materials, the maximum emission intensity was observed for the optimum composition of BaGd0.91La0.8B9O16Eu0.01 phosphor. The experimental results indicated that the Eu doped BaGdB9O16 and Ba（Gd,Ln）B9O16（Ln=La, Y） phosphors were promising red phosphors, which might find potential applications in near-UV excited LED lighting as well as display devices. Comparison of as-synthesized phosphors with standard phosphor used in CFL（compact fluorescent lamp） was also done. Energy transfer mechanism of Gd^3＋ to Eu^3＋ was also discussed in this paper.

关键词： phosphor solid state diffusion display devices photoluminescence rare earths

Combustion synthesis of Ce^(3+), Eu^(3+) and Dy^(3+) activated NaCaPO_4 phosphors

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Journal of Rare Earths 2011年第6期29卷 527-535页

作者： K N Shinde S J Dhoble Animesh Kumar department of physics RTM Nagpur University National Environmental Engineering Research Institute

The preparation of NaCaPO4 doped with rare earth （RE） ions Ce3＋, Eu3＋ and Dy3＋ by combustion method was described. Under UV excitation （251 nm） of NaCaPO4：Ce3＋ showsd emission （367 nm） in UV range. When NaCaPO4：Dy3＋ phosphor was excited at 349 nm, the emission spectrum showed intense bands at 482 nm （blue） and 576 nm （yellow）. In Eu activated NaCaPO4 phosphor, the emission spectrum showed a dominant peak at 594 nm （orange） while others were at 614 and 621 nm （red） when excited at 393 nm. The prepared phosphor was characterized by X-ray diffraction （XRD）, scanning electron microscope （SEM） and photoluminescence （PL） measurement. Thus, the photoluminescence behavior of NaCaPO4：Ce3＋ was strongly suggested for scintillator. Likewise, Eu3＋ and Dy3＋ activated NaCaPO4 phosphors were recommended for near-UV white light-emitting diodes （LEDs）.

关键词： combustion synthesis photoluminescence phosphor scintillator solid state lighting rare earths

Preliminary Archaeoacoustic Study of Kanheri Caves in Mumbai(Maharashtra,India)

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Sound & Vibration 2022年第2期56卷 193-203页

作者： Ajinkya S.Umbarkar Deoram V.Nandanwar Omprakash P.Chimankar department of physics SMM College of ScienceNagpur440009India department of physics RTM Nagpur University CampusNagpur440033India

Here we report first ever study on acoustical evaluation of Kanheri Caves located in Sanjay Gandhi National Park,Mumbai(Maharashtra,India).These caves are dated to a period between 2nd century BCE to 7th century *** this study we used an ambisonic recorder to capture Impulse Response,which carries acoustic signature of the *** of total 109 caves 41 were surveyed in available *** of those reverberant environment was noted in 12 *** were made only in 3 caves(Cave Nos.1,3,11)which are *** the beginning we carried out an FFT *** then studied room acoustic parameters like Reverberation Time,Early Decay Time,Clarity,Definition,etc.,based on the measurement of Impulse *** No.3 have high value of reverberation time,compared to *** it also have lower clarity compared to *** is properties needs to be compared with similar structures(chaityas)in Maharashtra(at Ajanta,Ellora,Nashik,Junnar,etc.)and elsewhere in *** is worthwhile to carry out further research in Cave No.3 with more sophisticated instruments as well as 3D *** the experiment was performed with receiver at only one position,we also suggest to carry out experiment with receiver at multiple positions and then comparing them.

关键词： Archaeoacoustics reverberation time room acoustics kanheri caves

Rare earth(Eu^(2+),Ce^(3+)) activated BaAl_2Si_2O_8 blue emitting phosphor

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Journal of Rare Earths 2014年第7期32卷 593-597页

作者： V.B.Pawade N.S.Dhoble S.J.Dhoble department of Applied-physics Laxminarayan Institute of Technology department of Chemistry Sevadal Mahila Mahavidyalay department of physics RTM Nagpur University

Blue emitting rare earth（Eu2＋,Ce3＋） doped BaAl2Si2O8 phosphors were synthesized by combustion methods at 600 oC. BaAl2Si2O8： Eu2＋ phosphor showed isolated broad blue emission band at 455 nm, when it was excited with the wavelength of 329 nm. Whereas BaAl2Si2O8：Ce3＋ phosphor exhibited blue emission band at 442 nm, under 303 nm excitation wavelength. These observed emission bands of Eu2＋ and Ce3＋ ions corresponded to 5d-4f allowed transitions. The position of emission band was calculated by using the equationE=Q[1-〔V/4〕^1/V）]× 10 （nEar/80）Also the spin orbit splitting difference in the ground state levels of Ce3＋ ion was studied by Gaussian curve fitting. Broad absorption and emission bands in blue regions made prepared phosphors a promising blue host for the white-LEDs.

关键词： optical materials spectroscopy luminescence crystal fields rare earths

Integral Transform Methods for Inverse Problem of Heat Conduction with Known Boundary of a Thin Rectangular Object and its Stresses

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Journal of Thermal Science 2012年第5期21卷 459-465页

作者： Navneet K. Lamba N. W. Khobragade department of Mathematics MJP Educational Campus RTM Nagpur UniversityNagpur 440 033 India

The three-dimensional inverse transient thermoelastic problem for a thin rectangular object is considered within the context of the theory of generalized thermoelasticity. The upper surface of the rectangular object occupying the space D： -a〈xSa; -b〈_y〈b; 0〈z〈h; with the known boundary conditions. Laplace and Finite Marchi-Fasulo transform techniques are used to determine the unknown temperature, temperature distribution, displacement and thermal stresses on upper plane surface of a thin rectangular object. The distributions of the considered physical variables are obtained and represented graphically.

关键词： Thin rectangular plate three dimensional inverse transient thermoelastic problem Marchi- Fasulo transform and Laplace transform.

Anisotropic Bianchi Type Ⅰ Cosmological Models with Generalized Chaplygin Gas and Dynamical Gravitational and Cosmological Constants

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Communications in Theoretical physics 2017年第2期67卷 222-230页

作者： S.Kotambkar G.P.Singh R.Kelkar Binaya K.Bishi department of Applied Mathematics LIT RTM Nagpur University Nagpur India department of Mathematics VNIT Nagpur India department of Applied Mathematics SB Jain ITMR Nagpur India

This paper deals with study of generalized Chaplygin gas model with dynamical gravitational and cosmological constants. In this paper a new set of exact solutions of Einstein field equations for spatially homogeneous and anisotropic Bianchi type Ⅰ space-time have been obtained. The solutions of the Einstein's field equations are obtained by considering(i) the power law relation between Hubble parameter H and scale factor R and(ii) scale factor of the form R =-1/t + t^2, t > 1. The assumptions lead to constant and variable deceleration parameter respectively. The physical and dynamical behaviors of the models have been discussed with the help of graphical representations. Also we have discussed the stability and physical acceptability of solutions for solution type-Ⅰ and solution type-Ⅱ.

关键词： Bianchi type Ⅰ space tine cosmological constant gravitational constant generalized Chaplygin gas

Effect of Synthesis Method on Photoluminescence Properties of Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) Nanophosphor

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Nano-Micro Letters 2012年第2期4卷 78-82页

作者： K.N.Shinde S.J.Dhoble K.Park N. S. Science and Arts College department of physics RTM Nagpur university Faculty of Nanotechnology and Advanced Materials Engineering Sejong University

We have synthesized a series of single-composition emission Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) phosphor by traditional solid state reactions and novel combustion method. Formation of compound was confirmed by X-ray diffraction analysis. The photoluminescence(PL) emission spectra were observed at 376 nm when excited around 322 nm for the various concentrations in both cases. The PL emission spectra of phosphors showed strong Ce^(3+)emission due to the 5d → 4f transition of Ce^(3+)ions. The Ce^(3+)emission intensity in Na_2Sr_2Al_2PO_4Cl_9:Ce^(3+) prepared by combustion was higher than that of solid state reactions.

关键词： Nanophosphor Luminescence Halophosphate

Synthesis of Y3Al5O12∶Eu and Y3Al5O12∶Eu,Si phosphors by combustion method: Comparative investigations on the structural and spectral properties

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Journal of Advanced Ceramics 2016年第4期5卷 248-页

作者： Manisha UPASANI department of physics Rashtrasant Tukadoji Maharaj Nagpur University Nagpur India

This paper reports the comparative investigations of the structural and spectral properties of Y3Al5O12∶Eu3+ (YAG∶Eu) and Y3Al5O12∶Eu3+,Si4+ (YAG∶Eu,Si) phosphors synthesized by combustion method at low temperature.A pure phase was identified for the YAG∶Eu phosphor with a suitable amount of *** refinement and analytical calculation of different structural parameters were performed to get the idea about the SiO2 substitution in YAG∶*** characteristic red luminescence corresponding to Eu3+ transitions was observed after irradiation with ultra violet (UV) light and enhanced with SiO2 *** formula and nephelauxetic ratio were used to understand the ligand behavior of Eu-O bond in YAG doped *** Judd-Ofelt intensity parameters and color properties of the phosphors were determined in *** efficient synthesis method for YAG∶Eu phosphor,compatible for industrial applications,was proposed.

关键词： yttrium aluminum garnet (Y3Al5O12,YAG) light emitting diode (LED) red phosphor combustion synthesis

A modified Murashige and Skoog media for efficient multipleshoot induction in G. arborea Roxb.

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Journal of Forestry Research 2014年第3期25卷 557-564页

作者： Shilpa S. Madke Konglanth J. Cherian Rupesh S. Badere department of Botany Hislop College department of Botany RTM Nagpur University M. J. Phuley Educational Campus

This paper reports on the effect of various micropropagation factors of Gmelina arborea Roxb. through multiple shoot induction. Factors like the source and age of explants, plant growth regulators （PGRs）, media composition, and carbon source affected multiple shoot-ing in the present study. Among all the explants used, only shoot tips derived from one, two, and three week old seedlings could form multiple shoots. Besides, the formation of multiple shoots depended on the con-centration and combination of PGRs. Among all the PGRs, BAP （6-benzylaminopurine） alone gave the highest regeneration efficiency. Simi-larly, IBA （Indole-3-butyric acid） was the most efficient PGR in inducing root formation in the microshoots. Media composition and carbon source also affected the regeneration efficiency. MS （Murashige and Skoog medium） proved to be the best media for regeneration followed by B5, SH （Schenk and Hilderbrandt medium） and WPM （Woody plant medium） in that order. Similarly, among sugars, only sucrose and glucose sup-ported induction of microshoots. Based on this study we recommend the use of glucose in place of sucrose in MS medium for maximum regenera-tion efficiency.

关键词： agroforestry micropropagation plant nutrition shoot tipexplant timber plant Verbenaceae

d-f luminescence of Ce^(3+) and Eu^(2+) ions in BaAl_(2)O_(4), SrAl_(2)O_(4) and CaAl_(2)O_(4) phosphors

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Journal of Advanced Ceramics 2017年第4期6卷 341-350页

作者： K.A.GEDEKAR S.P.WANKHEDE S.V.MOHARIL R.M.BELEKAR department of physics K.D.K.College of EngineeringNagpur 440009India department of physics Nagpur UniversityNagpur 440010India department of physics and Electronics Government Vidarbha Institute of Science and HumanitiesAmravati 444604India

Ce^(3+)and Eu^(2+)doped alkaline earth aluminates MAl_(2)O_(4)(M=Ca,Sr,Ba)were prepared by single-step combustion synthesis at low temperature(600℃).X-ray diffraction(XRD)analysis confirmed the formation of BaAl_(2)O_(4),CaAl_(2)O_(4),and SrAl_(2)O_(4).Photoluminescence spectra and optimal luminescent properties of Ce^(3+)and Eu^(2+)doped MAl_(2)O_(4) phosphors were *** between Eu^(2+)and Ce^(3+)f-d transitions was *** properties known for Ce^(3+)were used to predict those of Eu^(2+)by using Dorenbos’*** values thus calculated were in excellent agreement with the experimental *** preferential substitution of Ce^(3+)and Eu^(2+)at different Ba^(2+),Sr^(2+),Ca^(2+)crystallographic sites was *** dependence of emission wavelengths of Ce^(3+)and Eu^(2+)on local symmetry of different crystallographic sites was also studied by using Van Uitert’s empirical *** results matched excellently with the predictions of Dorenbos’and Van Uitert’s models.

关键词： Ce^(3+) Eu^(2+) photoluminescence X-ray diffraction(XRD) crystal structure