Sri Venkateswara University is a state university in Tirupati, Andhra Pradesh, India. It was founded in 1954 by chief minister Tanguturi Prakasam Pantulu. The university is named after Lord Venkateswara whose shrine is located in the city.The university campus covers a large area on land donated by Tirumala Tirupati Devasthanams. It is located on the West side of Tirupati, surrounded by the other universities in the city, namely Sri Padmavati Mahila Visvavidyalayam, Sri Venkateswara Veterinary University, Sri Venkateswara Vedic University, Sri Venkateswara Institute of Medical science and Rashtriya Sanskrit Vidyapeetha.The university was ranked #37 research university in 2013, and received an above average rating in 2014. It holds a NAAC rating of "A" with a score of 3.13 out of 4. It was the 31st university to be built in India, and after the Andhra Pradesh Reorganisation Act, 2014 it is the second oldest university in Andhra Pradesh, after Andhra University. Wikipedia.
Reddy V.R.,Sri Venkateswara University
Thin Solid Films | Year: 2014
The effect of polyvinylidene fluoride (PVDF) polymer interlayer on the rectifying junction parameters of Au/n-InP Schottky diode has been investigated using current-voltage (I-V) and capacitance-voltage (C-V) measurements at room temperature. The calculated barrier heights (BHs) are 0.57 eV (I-V), 0.72 eV (C-V) and 0.73 eV (I-V), 0.88 eV (C-V) for the Au/n-InP and Au/PVDF/n-InP Schottky diodes, respectively. Results showed that the BH of the Au/PVDF/n-InP Schottky diode is higher than that of the Au/n-InP Schottky diode, and that the PVDF film increases the effective BH by influencing the space charge region of the n-type InP. The values of the barrier height, ideality factors and series resistance estimated by I-V, Cheung's and Norde methods are compared. Experimental results showed that the interface state density of the Au/PVDF/n-InP Schottky diode is lower than that of the Au/n-InP Schottky diode. Further, the reverse leakage current conduction mechanism is investigated. Schottky emission mechanism is found to dominate the reverse leakage current in the Au/n-InP Schottky diode. However, for the Au/PVDF/n-InP Schottky diode, the Schottky conduction mechanism is found to be dominant in the higher bias region, whereas the Poole-Frenkel conduction is found to be dominant in the lower bias region. Apart from that, the discrepancy between BHs determined from I-V and C-V techniques is explained. Besides, the capacitance-frequency (C-f) and conductance-frequency (G-f) characteristics of the Au/PVDF/n-InP Schottky diode are discussed. © 2014 Elsevier B.V.
Basavapoornima Ch.,Sri Venkateswara University |
Jayasankar C.K.,Sri Venkateswara University
Journal of Luminescence | Year: 2014
The Sm3+-doped lead phosphate glasses (PKAPbNSm:44P 2O5-17K2O-9Al2O3-(24-x) PbO-6Na2O-xSm2O3, where x=0.1, 0.5, 1.0 and 2.0 mol%) have been prepared by conventional melt quenching technique and are characterized through absorption and emission spectra and decay rate analysis. The partial energy level structure of Sm3+ ions in these glasses have been evaluated from the measured absorption and emission spectra using free-ion Hamiltonian model. The emission spectra of Sm3+ ions in these glasses have been measured using 488 nm line of Ar+ laser as an excitation source. The decay rates for 4G5/2 level of Sm3+ ions have been measured and are found to exhibit single exponential nature at lower concentration (0.1 and 0.5 mol% Sm2O 3-doped glass) and turns into non-exponential at higher concentrations. © 2014 Elsevier B.V. All rights reserved.
Kumar K.S.,Sri Venkateswara University |
Reddy C.S.,Sri Venkateswara University
Organic and Biomolecular Chemistry | Year: 2012
Total synthesis of (+)-anamarine a polyoxygenated δ-pyranone natural product was accomplished via cross-metathesis protocol starting from 3-butene-1-ol and glycidol. Other key features of this synthetic strategy include use of Sharpless asymmetric epoxidation, dihydroxylation, and deoxygenation-isomerization through allene rearrangement. © The Royal Society of Chemistry 2012.
Jaidev L.R.,Sri Venkateswara University |
Narasimha G.,Sri Venkateswara University
Colloids and Surfaces B: Biointerfaces | Year: 2010
Microbial assisted biosynthesis of nanoparticles is a rapidly progressing area of nanobiotechnology. In this paper Aspergillus niger assisted extracellular synthesis of silver nanoparticles is reported. The silver nanoparticles were characterized by UV-vis spectrophotometry, TEM, EDX and FTIR. TEM studies showed the size of the silver nanoparticles to be in the range of 3-30. nm. The probable mechanism for the extracellular synthesis of silver nanoparticles by Aspergillus niger was investigated. The nanoparticles showed antimicrobial activity against fungal and bacterial strains. © 2010 Elsevier B.V.
Kesavulu C.R.,Sri Venkateswara University |
Jayasankar C.K.,Sri Venkateswara University
Materials Chemistry and Physics | Year: 2011
Lead fluorophosphate (PbFPDy: P2O5 + K2O + Al2O3 + PbF2 + Na2O + Dy 2O3) glasses doped with different Dy3+ ion concentrations have been prepared and characterized through Raman, absorption, emission and decay rate measurements. Free-ion Hamiltonian model for energy level analysis and Judd-Ofelt theory for spectral intensities have been used to analyze the spectroscopic properties of Dy3+ ions in lead fluorophosphate glasses. The chromaticity coordinates were calculated from emission spectra and analyzed with Commission International de I'Eclairage color diagram and appear in the white light region under ultraviolet excitation. The decay rates for 4F9/2 level have been measured and are found to be deviated from exponential to non-exponential nature with increase in Dy3+ ion concentration. The non-exponential decay rates have been fitted with the Inokuti-Hirayama model for S = 6, which revealed that dipole-dipole mechanism is responsible for the energy transfer processes through Dy3+-Dy3+ interaction. © 2011 Elsevier B.V. All rights reserved.