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Srinivas, M.
- Luminescence Studies of Eu3+ Doped BaGd2O4 Phosphor
Abstract Views :503 |
PDF Views:137
Authors
M. Srinivas
1,
B. Appa Rao
1
Affiliations
1 Department of Physics, Osmania University, Hyderabad-500 007, IN
1 Department of Physics, Osmania University, Hyderabad-500 007, IN
Source
Indian Journal of Science and Technology, Vol 5, No 7 (2012), Pagination: 3022-3026Abstract
The spectroscopic properties of BaGd2-xO4:Eux (x = 0.0 - 0.1) phosphors were investigated. The phosphors were synthesized by conventional solid state reaction method. The samples were characterized by powder-XRD and energy dispersive spectroscopy (EDS) techniques. The photoluminescence (PL) and thermally stimulated luminescence (TSL) studies of these materials were investigated. For PL studies the samples were excited with 258 nm UV light. All the samples showed strong red emission at 611 nm due to 5D0→7F2 electric dipole transition of Eu3+ ions. PL peak intensity was found to increase with increase in the dopant concentration. For TSL studies, samples were γ-irradiated with different dose rates using 60Co source. TSL of these phosphors showed a sharp glow peak with maxima at 394 K. Incorporation of europium activator in BaGd2O4 phosphor resulted in the increase of peak intensity. The trap parameters viz., order of kinetics (b), activation energy (E) and frequency factor (S) associated with the most intensive glow peak of BaGd2O4:Eu3+ phosphor were determined using glow curve shape (Chen's) method. These phosphors can be useful in TL dosimetry.Keywords
Phosphors, Photoluminescence, U.V Excitation, Thermoluminescence, DosimetryFull Text
References
- Kang CC and Liu RS (2007) The effect of terbium concentration on the luminescent properties of yttrium oxysulfide phosphor for FED application, J. Lumin. pp: 122–123, pp: 574–576.
- Ko MG, Park JC, Kim DK and Byeon SH (2003) Lowvoltage cathodoluminescence property of Li-doped Gd2_xYxO3 : Eu3+. J. Lumin. 104, 215–221.
- Lai Hh, Chen Bj, Xu W, Xie Yh, Wang Xj and Di WH (2006) Fine particles (Y,Gd)PxV1-xO4 : Eu3+ phosphor for PDP prepared by co-precipitation reaction, Mater. Lett. 60, 1341–1343.
- Jung HK and Seo KS (2006) Luminescent properties of Eu2+-activated (Ba, Sr)3MgSi2O8 phosphor under VUV irradiation, Opt. Mater. 28, 602–605.
- Hsu WT, Wu WH and Lu CH (2003) Synthesis and luminescent properties of nano-sized Y3Al5O12 : Eu3+ phosphors, Mater. Sci. Engg. B104, 40–44.
- Jean-Charles Souriau, Yong Dong Jiang, John Penczek, Henry Paris G and Christopher Summers J (2000) Cathodoluminescent properties of coated SrGa2S4:Eu2+ and ZnS:Ag,Cl phosphors for field emission display applications Mater. Sci. Engg. B76, 165-168.
- Nemec P and Maly P (2000) Temperature study of trap-related photoluminescence decay in CdSxSe1-x nanocrystals in glass, J. Appl. Phys. 87, 3342.
- Bol AA and Meijerink A (2000) Doped semiconductor nanoparticles - a new class of luminescent materials? J. Lumin. 87, 315-318.
- Yoshihiro D, Wataru N and Yukio H (2006) Crystal structures and magnetic properties of magnetically frustrated systems BaLn2O4 and Ba3Ln4O9 (Ln = lanthanide), J. Phys. Condens. Matter. 18, 333–344.
- Manivannan V, Comanzo HA, Setlur AA, Srivastava AM, Schmidt PA and Happek U (2003) Nature of luminescent centers in Cerium activated materials with the CaFe2O4 structure, J. Lumin. pp: 102–103, pp: 635–637.
- Brixner LH (1967) Fluorescence and Cathodoluminescence of Eu3+ in Some alkali and alkaline earths-yttrates and gadolinates as hosts. J. Electrochem. Soc. Solid State Sci. 114, 252–254. JCPDS No. 42-1496.
- Kubota S, Suzuyama Y, Yamane H and Shimada M (1998) Luminescence properties of LiSr2Y1-xLnxO4 (Ln=Eu,Tb,Tm) (0=x=1) J. Alloys Compd. 268, 66-71.
- Blasse G and Brill A (1967) Fluorescence of Eu3+- Activated Lanthanide Oxyhalides J. Chem. Phys. 46, 2579-2582.
- Pires AM, Santos MF, Davolos MR and Stucchi EB (2002) The effect of Eu3+ ion doping concentration in Gd2O3 fine spherical particles. J. Alloys Compd. 344, 276-279.
- Shionoya S and Yen WM (1999) Phosphor handbook CRC Press, Boca raton. pp: 190.
- Taibi M, Aride J, Antic-Fidancev E and Lemaitre- Blaise M (1994) Etude de la fluorescence de Eu3+ dans BaRE2O4 (RE = Gd, Y). Détermination des paramètres du champ cristallin. Phys. Status Solid. A144, 453-459.
- LIDE D (2002) Editor in chief, the CRC handbook of Chemistry and Phys. On CD-ROM, CRC Press, Version. 22.
- Chuai XH, Zhang HJ, Sh Li F, Sh Z Lu, J Lin, Sh B Wang and Chou KC (2002) Synthesis and luminescence properties of oxyapatite NaY9Si6O26 doped with Eu3+, Tb3+, Dy3+ and Pb2+. J.Alloys Compd. 334, 211-218.
- Chen R and Mc Keever SWS (1997) Theory of thermoluminescence and related phenomenon. World Scientific Singapore. pp: 29.
- Mineral Chemistry and Geochemistry of the Mesocratic Quartz Syenite Intrusions from Vikurthi and Kotappakonda, Guntur District, Andhra Pradesh
Abstract Views :201 |
PDF Views:4
Authors
Affiliations
1 Department of Geology, Kakatiya University, Warangal-506 009, IN
2 Department of Geology, Osmania University, Hyderabad-500 007, IN
3 National Geophysical Research Institute, Hyderabad-500007, IN
4 Department of Earth Sciences, Bullard Laboratories, Madingley Rise; Cambridge, CB2 3EQ, IN
1 Department of Geology, Kakatiya University, Warangal-506 009, IN
2 Department of Geology, Osmania University, Hyderabad-500 007, IN
3 National Geophysical Research Institute, Hyderabad-500007, IN
4 Department of Earth Sciences, Bullard Laboratories, Madingley Rise; Cambridge, CB2 3EQ, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 45, No 5 (1995), Pagination: 519-529Abstract
The paper presents the mineral analyses and the major, trace and rare earth element geochemistry of the subalkaline syenites from Vikurthi and Kotappakonda in the Guntur district of Andhra Pradesh. A comprehensive model is proposed wherein these and other similar rocks from the Cuddapah intrusive province are envisaged as the differentiated products of an intermediate magma of trachybasaltic composition, which, in turn, has been derived by the differentiation of a parental gabbro magma.Keywords
Geochemistry, Syenites, Igneous Petrology, Guntur District, Andhra Pradesh.
- Petrology and Petrogenesis of Syenites from the Cuddapah Basin, Andhra Pradesh
Abstract Views :211 |
PDF Views:1
Authors
Affiliations
1 Geology Department, Kakatiya University, Warangal - 506 009, IN
2 National Geophysical Research Institute, Hyderabad - 500 007, IN
3 Geology Department, Osmania University, Hyderabad - 500 007, IN
1 Geology Department, Kakatiya University, Warangal - 506 009, IN
2 National Geophysical Research Institute, Hyderabad - 500 007, IN
3 Geology Department, Osmania University, Hyderabad - 500 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 43, No 3 (1994), Pagination: 225-237Abstract
Rare bodies of syenites of alkaline or subalkaline character occur as intrusions in the rocks of the Cuddapah Supergroup within the Cuddapah basin. The alkali syenites (found at Racherla, Idamakallu and Giddalur) are mainly composed of riebeckite (arfvedsonite), ilmenite, orthoclase and the subalkaline syenites (located at Gundlapalle) comprise hedenbergite, and microcline-perthite. Accessory quartz is invariably present in both the syenites. These intrusive bodies display contrasting mineralogical and geochemical characteristics. The quartz- and hypersthenenormative subalkaline syenite has the attributes of a ferrosyenite and has been subjected to hydrothermal alteration which not only resulted in the formation of secondary minerals like nontronite, amphibole, biotite and magnetite- all at the expense of hedenbcrgite, but also partly converted the Fe+2 into Fe +3. These subalkaline syenites are characterized by an extreme paucity of Mg, has low to moderate contents of Ba, Sr, Rb, Zr and REE. The quartz, hypersthene and acmite- normative alkali syenites (lusitanite) on the other hand are abnormally enriched in Ti; Rb is low but Ba, Sr, Ce, Nb, Nd, Ta, Sm, La, Zr am also the ratios K/Rb, Ti/Zr, Ce/Y and HREE/LREE are conspicuously high.
The syenites of the Cuddapah basin, seem to have crystallized under contrasting conditions. While the alkali syenites crystallized under high PH2O, the crystallization of subalkaline syenite took place under dry arid reducing conditions signifying a closed system. It is envisaged that the subalkaline ferrosyenite of Gundlapalle was formed by low-pressure crystal fractionation of a continental tholeiitic basaltic magma. The alkali syenites, on the other hand, are postulated to have crystallized from a mantle-derived, hydrous, alkaline magma enriched in Large Ion Lithophile Elements and Light Rare Earth Elements.
Keywords
Syenites, Igneous Petrology, Cuddapah Basin, Andhra Pradesh.- Mid-Proterozoic Intraplate Alkaline Magmatism in the Eastern Dharwar Craton of India: The Cuddapab Province
Abstract Views :165 |
PDF Views:2
Authors
Affiliations
1 Department of Geology, Kakatiya University, Warangal-506009, IN
2 National Geophysical Research Institute, Hyderabad-500007, IN
3 Department of Geology, P.G. College of Science, Saifabad, Osmania University, Hyderabad-500004, IN
1 Department of Geology, Kakatiya University, Warangal-506009, IN
2 National Geophysical Research Institute, Hyderabad-500007, IN
3 Department of Geology, P.G. College of Science, Saifabad, Osmania University, Hyderabad-500004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 53, No 2 (1999), Pagination: 143-162Abstract
In the Dharwar craton, the recently recognized Cuddapah intrusive province hosts an array of mid-Proterozoic alkaline and non-alkaline intrusives; the latter are represented by two manifestly voluminous magma types: gabbro and granitoid, which are marked by a bimodal association. Here we present the tectono-magmatic framework of the Cuddapah intrusive province and in the light of it, the petrology, geochemistry and genesis of alkaline rocks are discussed to highlight the mid-Proterozoic intraplate alkaline magmatism in the eastern Dharwar craton.Keywords
Igneous Petrology, Alkaline Magmatism, Mid-Proterozoic, Cuddapah Province, Eastern Dharwar Craton.- Comparative Study of Lamprophyres from the Cuddapah Intrusive Province (CIP) of Andhra Pradesh, India
Abstract Views :190 |
PDF Views:2
Authors
Affiliations
1 Department of Geology, Kakatiya University, Warangal, A.P. - 506 009, IN
2 National Geophysical Research Institute, Hyderabad- 500 007, IN
3 Department of Applied Geochemistry, Osmania University, Hyderabad- 500 007, IN
4 Department of Geology, Osmania University, Hyderabad- 500 007, IN
1 Department of Geology, Kakatiya University, Warangal, A.P. - 506 009, IN
2 National Geophysical Research Institute, Hyderabad- 500 007, IN
3 Department of Applied Geochemistry, Osmania University, Hyderabad- 500 007, IN
4 Department of Geology, Osmania University, Hyderabad- 500 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 52, No 6 (1998), Pagination: 621-642Abstract
The mid-Proterozoic lamprophyric rocks broadly represented by kimberlites, lamproites and lamprophyres (sensu stricto) are emplaced in and adjacent to the intracratonic Cuddapah basin in the eastern Dharwar craton of India which was recently recognized as the Cuddapah (intrusive) province (CIP). While the kimberlite pipes and lamprophyre dykes are located outside but close to the western and eastern margins of the Cuddapah basin respectively, the lamproites are hosted within the basin. Lamprophyres occur in seven locations of the Prakasam district of Andhra Pradesh. EIchuru, where more than one hundred lamprophyre dykes are found, represents a prominent centre of lamprophyre magmatism. Purimetla comes next to Elchuru with a tally of twenty lamprophyre dykes. At other places lamprophyres are numerically insignificant. The CIP lamprophyres encompass different varieties and they cut across an equally wide-ranging variety of host rocks; these lamprophyres come under 1) feldspathoidal or non- feldspathoidal and 2) plagioclase- or orthoclase-bearing categories. With a single exception, all the lamprophyres are micaceous and distinctly alkaline. The genesis of CIP lamprophyres as a manifestation of alkaline magmatism is discussed.Keywords
Petrology, Geochemistry, Lamprophyres, Cuddapah Province, Andhra Pradesh.- Photoluminescence studies of Eu3+ doped Y2O3 phosphor
Abstract Views :202 |
PDF Views:0
Authors
Affiliations
1 Department of Physics, Osmania University, Hyderabad – 500007, Telangana, IN
1 Department of Physics, Osmania University, Hyderabad – 500007, Telangana, IN
Source
Indian Journal of Science and Technology, Vol 10, No 18 (2017), Pagination:Abstract
Objectives: This paper reports the efficiency studies of Eu3+ doped Yttrium Oxide red phosphor suitable for lamps and display applications. Methods: The samples are synthesized by conventional solid-state reaction method using consistent oxide materials. Findings: The prepared phosphor material is characterized with Powder X-Ray Diffraction (XRD) and Energy Dispersive X-ray Analysis (EDAX) techniques. The Photoluminescence characteristics of the sample are studied using UV excitation light of 258 nm. Upon excitation with UV light, the phosphor show a strong red emission line at around 612 nm corresponds to the electric dipole transition 5D0→7F2 of Eu3+ and the PL intensity increases with increasing Eu3+ doping concentration. Applications: This material appears to be promising red emission which is suitable for lamp industry and display devices.Keywords
Photoluminescence, EDAX, Phosphors, XRD, UV Excitation, Y2O3:Eu3+Full Text
- Microwave Assisted Synthesis and Antibacterial Activity of Some Bicyclic Pyrrolidines
Abstract Views :144 |
PDF Views:0
Authors
Affiliations
1 Department of Pharmaceutical Sciences, Andhra University, Visakhapatnam-530003, IN
2 Enzene Biosciences Pvt. Ltd., Bangalore, IN
1 Department of Pharmaceutical Sciences, Andhra University, Visakhapatnam-530003, IN
2 Enzene Biosciences Pvt. Ltd., Bangalore, IN
Source
Asian Journal of Research in Chemistry, Vol 2, No 3 (2009), Pagination: 357-359Abstract
An improved method for the synthesis of bicyclic pyrrolidines utilizing microwave-assisted synthesis is described. The synthesis involves microwave irradiation of an amine, aldehyde and maleimide in one pot fashion to give the desired product. The synthesized compounds were evaluated for their antibacterial activity against ciprofloxacin.- Dynamic model of heat ventilation and air conditioning (HVAC) system
Abstract Views :170 |
PDF Views:0
Authors
M. Srinivas
1,
K. S. Swarup
1
Affiliations
1 Department of Electrical Engineering, Indian Institute of Technology, Madras, Chennai - 600 036, IN
1 Department of Electrical Engineering, Indian Institute of Technology, Madras, Chennai - 600 036, IN