http://nopr.niscair.res.in/handle/123456789/11253 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/11320 Title: Rare earth Ce³⁺, Dy³⁺ activated Li₂BPO₅ phosphors for lyoluminescence dosimetry <br/> <br/>Authors: Puppalwar, S P; Dhoble, S J; Kumar, Animesh <br/> <br/>Abstract: Rare earth Ce and Dy doped polycrystalline Li₂BPO₅ phosphors were prepared by high temperature solid state reaction. Photoluminescence emission spectra of the phosphor suggest the presence of Ce³⁺ions in Li₂BPO₅:Ce and Dy³⁺ ions in Li₂BPO₅:Dy lattice sites. The prepared phosphors were characterized by the X-ray powder diffraction and photoluminescence techniques. The PL emission spectrum of Dy³⁺ ion under 348 nm excitation was observed at 481 nm (blue) due to⁴F_9/2→ ⁶H_15/2transitions and 576 nm (yellow) emission due to ⁴F_9/2→ ⁶H_13/2transitions in prepared borophosphate phosphor. The PL emission spectra of Ce³⁺ion was observed at 346 nm in ultraviolet region by 235 nm excitation. In this paper, PL and lyoluminescence (LL) characteristics of Li₂BPO₅:Ce, Dy borophosphate phosphors have been reported. The LL results show the LL emission of Li₂BPO₅:Ce³⁺, Dy³⁺phosphor in blue-yellow region of the spectrum and linear response curve of LL with gamma rays exposure up to 3.5 kGy. These LL characteristics of Li₂BPO₅:Ce³⁺, Dy³⁺phosphor may be useful for high radiation dose using LL technique. <br/> <br/>Page(s): 239-244 http://nopr.niscair.res.in/handle/123456789/11319 Title: Luminescence and electrical resistivity properties of cadmium oxide nanoparticles <br/> <br/>Authors: Lanje, Amrut S; Ningthoujam, Raghumani S; Sharma, Satish J; Pode, Ramchandra B <br/> <br/>Abstract: Cadmium oxide (CdO) nanoparticles have been prepared by precipitation method using cadmium acetate and ammonia solution. The electrical resistivity (ρ) has been measured at low temperature using four-probe method which is found to be 0.351 Ω-cm at 7 K and 0.264 Ω-cm at 300 K, respectively. The decrease of resistivity with increasing temperature indicates the semiconducting behaviour. The activation energy values are found to be 0.06 meV in temperature range 7-15 K and 0.6 meV in 39-152 K from temperature dependent resistivity. Photoluminescence (PL) spectrum shows band edge emission at 395 nm and green emission at 550 nm. Green emission arises from the oxygen vacancy of CdO materials because of recombination of a photo generated hole in valence band with an electron in conduction band. <br/> <br/>Page(s): 234-238 http://nopr.niscair.res.in/handle/123456789/11318 Title: ZnO nanorods and nanopolypods synthesized using microwave assisted wet chemical and thermal evaporation method <br/> <br/>Authors: Singh, A K; Multani, S S; Patil, S B <br/> <br/>Abstract: Zinc oxide (ZnO) nanostructures have been grown on glass and silicon substrate by microwave assisted wet-chemical (MAWC) method and thermal evaporation using TGA. The effect of different preparative parameters on the growth of ZnO nanostructures has been studied. The synthesized nanostructures are characterized using UV-Vis spectroscopy, particle size analyzer, XRD, SEM, and EDX. ZnO nanostructures, i.e. nanorods (NRs) obtained using evaporation method are of 200-250 nm in diameter and nanopolypods (NPPs) with pod diameter in the range 150-200 nm and pod length in the range 700-800 nm, whereas from MAWC method, NRs produced are 100-150 nm in diameter and NPPs with pod diameter in the range 150-200 nm and 1.5-2 µm of pod length. XRD studies show that the prepared samples are nanocrystalline in nature with hexagonal wurtzite phase and highly oriented along (002) direction. <br/> <br/>Page(s): 270-276 http://nopr.niscair.res.in/handle/123456789/11317 Title: Scaled quantum chemical study of structure and vibrational spectra of 5-fluro-2-hydroxyacetophenone <br/> <br/>Authors: Anbarasu, P; Arivazhagan, M <br/> <br/>Abstract: The solid phase FTIR and FT-Raman spectra of 5-fluro-2-hydroxy acetophenone (FHAP) have been recorded in the regions 4000-400 cm^-1 and 3500-50 cm^-1, respectively. The spectra were interpreted with the aid of normal coordinate analysis following full structure optimization and force field calculations based on density functional theory (DFT) using standard B3LYP/6-311+G(d,p) and B3LYP/6-311++G(d,p) methods and basis set combinations and were scaled using various scale factors yielding fairly good agreement between the observed and calculated frequencies. Based on the good quality scaled quantum mechanical force field, a reliable description of the fundamental was provided and the assignments have been proposed with the aid of normal coordinate analysis. <br/> <br/>Page(s): 227-233