Ceylon Journal of Science (Physical Sciences)
Permanent URI for this collectionhttps://dl.nsf.gov.lk/handle/1/9787
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Item Antitermite and antifungal activity of usnic acid and atranorin(University of Perdeniya. Peradeniya, 1999) Bombuwala, K.; Subramaniam, V.; De Silva, K.S.; Karunaratne, V.; Adikaram, N.K.B.; Herath, H.M.T.B.Item Asymptotic normality of a proposed estimator(University of Perdeniya. Peradeniya, 1999) Thewarapperuma, P.S.S.Item Chemical and structural studies on natural spinels, MgAl2O4, of Sri Lanka(University of Peradeniya. Peradeniya, 1995) Udawatte, C.P.; Gunawardena, R.P.; Annersten, H.Natural Spinels from Sri Lanka (Ratnapura and Bibile) have been found to be mainly in the form, MgAl204 , with minor substitutions of Fe (0.7-3.5 wt% FeO) and Zn (0.07-4.4 wt% ZnO). Concentrations of other elements such as Cr, Co, Ni, V, and Mn were very low and, less than 0.1 wt% oxide. The natural spinels were found to have a complete normal cation distribution, A II[ ,(B III2)O4, suggesting an origin from a slow cooling rock forming process of the igneous and metamorphic rocks. Available experimental data of the Sri Lankan natural spinels indicate that complete ordering occurs at 280 ±175oC. The lattice constants were in the range of 8.087-8.091 A. Heating of the natural spinel results in disordering which may lead to a decreasing cell edge. Disordering of Al at 1000oC, as determined from AI-NMR spectroscopy, shows 13% of the Al occupying the tetrahedral sites. Optical spectra in the visible region are dominated %y spin forbidden transitions in Fe2+ and in some Cr-rich samples by spin allowed transitions in chromium. These are the main features that determine the colour of natural spinels investigated in the present study. The study indicates that the natural spinels have ordered cation distribution and the cation distribution in tetrahedral and octahedral sites depends on the thermal history of the crystal. The presence of transition elements, mainly Fe and Cr upto about 0.01 wt% oxide is sufficient to produce intense colour in spinels.Item Chemical modification of polyethene and immobilization of conducting polyaniline(University of Peradeniya. Peradeniya, 2002) Perera, J.S.H.Q.; Tennakoon, D.T.B.; Rajapakse, R.M.G.; Bandara, A.; Weerasinghe, J.K.K.Item Classification of state schools in Sri Lanka. a multivariate approach(University of Peradeniya. Peradeniya, 2002) Dorabawila, S.S.K.B.M; Samita, S.; Thattil, R.O.Item Comparative acidulation studies of the matrix and the single crystals of the Eppawela apatite and XRD identification of byproducts(University of Peradeniya. Peradeniya, 2009) Wimalasena, R.D.; Udawatte, C.P.; Ileperuma, O.A.Item Comparative electrochemical activity of the insecticide, endosulfan, at bare and 5,10,15,20-tetraphenylporphyrinato iron(III) chloride-modified glassy carbon electrodes(University of Perdeniya. Peradeniya, 1999) Priyantha, N.; Malavipathirana, S.Item Construction of a keV pulsed ion source and the measurement of damage cross -sections for keV ion induced sputtering from solid targets(University of Peradeniya. Peradeniya, 1997) Barlodaya, D.D.N.; Ariyaratne, T.R.; Hankansson, P.; Sundqvist, B.U.R.; Ens, W.Item Cost effective electroanalytical methodology for the detection of 3,4- Dichloroaniline(3,4DCA), the primary residue of propanil(University of Peradeniya. Peradeniya, 2009) Navaratne, A.; Nafil, A.M.; Ekanayake, C.B.Item CUBRAS. Design and implementation of the course unit based results analysis system(University of Peradeniya. Peradeniya, 2009) Kodituwakku, S.R.; Chamikara, P.Item Development of an opto-chemical sensor for the detection of Cu2+ ions in aqueous solution(University of Peradeniya. Peradeniya, 2002) Bandara, H.M.N.; Perera, J.S.H.Q.; Tennakoon, D.T.B.; Rajapakse, R.M.G.; Jayatissa, S.D.S.; Illangantilaka, A.N.; Jayasuriya, G.R.U.Item Development of client-server based network centric remote data acquisition system(University of Perdeniya. Peradeniya, 1999) Obadage, C.T.; Ranasinghe, D.N.; Jayananda, M.K.; Sonnadara, D.U.J.Item Dye-sensitized semiconductor nanostructures for solar energy conversion(University of Peradeniya. Peradeniya, 2002) Tennakone, K.Item Economic design of fraction non-confirming quality control chart(University of Peradeniya. Peradeniya, 2009) Thilakarathne, L.R.; Daundasekera, W.B.Item Effect of As substitution on superconducting properties of the (Bi,Pb)-Sr-Ca-Cu-O System(University of Peradeniya. Peradeniya, 1995) Dissanyake, M.A.K.L. and othersSuperconducting properties of three systems with nominal stoichiometry (Bi0.7Pb0.3)SrCaCu1.5Oy (Sample A), (Bi0.5As0.2Pb0.3)SrCaCu1.5Oy(Sample B) and (Bi0.7As0.2Pb0.1)SrCaCu1.5Oy (Sample C) have been investigated using electrical resistivity, ac magnetic susceptibility and X-ray power diffraction measurements. Results show that, As is incorporated into the structure in sample B, still retaining superconducting properties but with a lower Tc of 80K. Sampel C where As is expected to replace Pb, however, does not show superconductivity and exhibit multiphase behaviour with several impuirty phases.Item Electrical properties of zircon ceramics doped with different dopants(University of Peradeniya. Peradeniya, 2002) Dahanayake, U.; Karunaratne, B.S.B.Item Electrical relaxation in some peo-based solid polymer elctrolytes(University of Peradeniya. Peradeniya, 2002) Bandara, L.R.A.K.; Dissanayake, M.A.K.L.Item Eletroanalytical methods for detection of the fungicide, copper oxychloride(University of Perdeniya. Peradeniya, 1999) Priyantha, N.; Malavipathirana, S.; Jayaratne, P.Item Enhanced densification of In2O3. Sn (ITO) ceramics prepared from by hydrothermally derived Sn doped indium hydroxide powder(University of Peradeniya. Peradeniya, 2002) Udawatte, C.P.; Yanagisawa, K.Item Equivalence of square designs, difference sets and complete graphs(University of Peradeniya. Peradeniya, 2009) Perera, A.A.I.
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