Pharmacognostical Evaluation of Andrographis stenophylla C. B. Clarke

R. Vijaya Bharathi,C. Vamsadhara 한국생약학회 2007 Natural Product Sciences Vol.13 No.3

Andrographis stenophyllanarrow leaves and stems from a stout rotstock, the corolla pale with dark red stripes. The plant grows in hills ofabout 1200 meters height in South India. No scientific work reports are available with regard to this plant. Thepresent study, thus deals with the detailed pharmacognostical evaluation of the plant A. stenophylla using light andconfocal microscopy, WHO recomended physico-chemical determinations and authentic phytochemicalprocedures. The physico-chemical, morphological and histological parameters presented in this paper may beA. stenophylla and can possibly help to differentiate thedrug from its other species.Keywords Andrographis stenophylla, Acanthaceae, pharmacognosy, HPTLC and HPLC

Electrical Properties of Copper Substituted Nickel Ferrites

G. Ravi Kumar,Y. C. Venudhar,A. T. Raghavender,K. Vijaya Kumar 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.7

The Ni-Cu ferrites, Ni1−xCuxFe2O4 (0.0 ≤ x ≤ 1.0) were prepared by using the sol-gel method. The X-ray diffraction patterns of all the samples showed the formation of a single-phase spinel structure. The lattice parameter was found to increase with increasing copper concentration. The electrical properties, such as the d. c. conductivity as a function of the temperature, and the dielectric constant, the dielectric loss factor and the dielectric loss tangent as function of the frequency were investigated. The d. c. conductivity was found to increase with increasing temperature in accordance with the Verwey hopping mechanism. The dielectric constant, the dielectric loss factor and the dielectric loss tangent were found to decrease with increasing frequency. The dielectric constant followed the Maxwell-Wagner interfacial polarization. A suitable explanation was given for the frequency and the composition dependences of the dielectric properties.

Local field dependent fluorescence properties of Eu³⁺ ions in a fluorometaphosphate laser glass

Babu, P.,Jang, K.H.,Kim, E.S.,Vijaya, R.,Jayasankar, C.K.,Lavin, V.,Seo, H.J. North-Holland 2011 Journal of non-crystalline solids Vol.357 No.10

A fluorometaphosphate laser glass doped with Eu<SUP>3+</SUP> ions has been synthesized and studied by broad band optical spectroscopy and time-resolved fluorescence line narrowing techniques in order to explore the local field dependent fluorescence properties of the lanthanide ions in this host. From the Raman and the vibronic spectra, various structural phosphate groups coupled to the Eu<SUP>3+</SUP> ions have been identified. Local field dependent <SUP>5</SUP>D<SUB>0</SUB>→<SUP>7</SUP>F<SUB>J</SUB> (J=0-6) emission spectra and the lifetimes of the <SUP>5</SUP>D<SUB>0</SUB> level have been measured under resonant excitation of the Eu<SUP>3+</SUP> ions at different wavelengths within the <SUP>7</SUP>F<SUB>0</SUB>→<SUP>5</SUP>D<SUB>0</SUB> band at 16K. From these data and using the Stark level positions of the <SUP>7</SUP>F<SUB>1</SUB> and <SUP>7</SUP>F<SUB>2</SUB> multiplets, a crystal-field analysis has been carried out assuming a C<SUB>2v</SUB> orthorhombic local symmetry. The radiative Judd-Ofelt parameters have been calculated for the different local fields found in the glass and their relative variation has been discussed. The results obtained suggest the existence of a relatively narrow distribution of local fields generated by successive distortions of a unique kind of site for all the Eu<SUP>3+</SUP> ions in this fluorometaphosphate glass.

Binder-free cobalt phosphate one-dimensional nanograsses as ultrahigh-performance cathode material for hybrid supercapacitor applications

Sankar, K. Vijaya,Lee, S.C.,Seo, Y.,Ray, C.,Liu, S.,Kundu, A.,Jun, S.C. Elsevier Sequoia 2018 Journal of Power Sources Vol. No.

<P><B>Abstract</B></P> <P>One-dimensional (1D) nanostructure exhibits excellent electrochemical performance because of their unique physico-chemical properties like fast electron transfer, good rate capability, and cyclic stability. In the present study, Co<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> 1D nanograsses are grown on Ni foam using a simple and eco-friendly hydrothermal technique with different reaction times. The open space with uniform nanograsses displays a high areal capacitance, rate capability, energy density, and cyclic stability due to the nanostructure enhancing fast ion and material interactions. Ex-situ microscope images confirm the dependence of structural stability on the reaction time, and the nanograsses promoted ion interaction through material. Further, the reproducibility of the electrochemical performance confirms the binder-free Co<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> 1D nanograsses to be a suitable high-performance cathode material for application to hybrid supercapacitor. Finally, the assembled hybrid supercapacitor exhibits a high energy density (26.66 Wh kg<SUP>−1</SUP> at 750 W kg<SUP>−1</SUP>) and longer lifetimes (80% retained capacitance after 6000 cycles). Our results suggests that the Co<SUB>3</SUB>(PO<SUB>4</SUB>)<SUB>2</SUB> 1D nanograss design have a great promise for application to hybrid supercapacitor.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Binder-free cobalt phosphate cathode for hybrid supercapacitor. </LI> <LI> Stable structure and good electrochemical interaction confirmed via morphology. </LI> <LI> Uniform and direct growth enhances the electrochemical performance. </LI> <LI> The OH<SUP>−</SUP> ions more favor for large energy storage than NO<SUB>3</SUB> <SUP>−</SUP> ions. </LI> <LI> Ex-situ analysis confirms the influence of morphology on cyclic stability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

HAUSDORFF DIEMENSION OF CANTOR-LIKE SETS

Moorthy, C. Ganesa,Vijaya, R.,Venkatachalapathy, P. Department of Mathematics 1992 Kyungpook mathematical journal Vol.32 No.2

Broad Band Absorbance of Barium Hexaferrite Thick Films in the 8-12 GHz Frequency Spectrum

D. C. Kulkarni,Vijaya Puri 대한금속·재료학회 2011 ELECTRONIC MATERIALS LETTERS Vol.7 No.1

Screen printed barium hexaferrite thick films on alumina with broad band absorbance in the X band were fabricated. BaFe12O19 was synthesized using a cost effective low temperature co-precipitation method with varying Fe/Ba molar ratio and pH. The thick film showed increased grain size for higher Fe/Ba molar ratio. The complex permittivity and permeability of these thick films showed wavelike behavior in a range of 9.5GHz to 10.5 GHz. Synthesis conditions of hexaferrite powder and the dependency of the complex permittivity and the permeability of BaFe12O19 thick films on thickness in the 8 to 12 and the permeability of BaFe12O19thick films in the 8 GHz to 12 GHz frequency spectrum are discussed in this paper. The high frequency (8 GHz to 12 GHz) reflection loss of thick film barium hexaferrite was investigated and was found to be dependent on the synthesis parameters and the thickness of the thick films. The absorption measured was more than 80% over the entire X band.

Global Approach for Script Identification using Wavelet Packet Based Features

M.C. Padma,P. A. Vijaya 보안공학연구지원센터(IJSIP) 2010 International Journal of Signal Processing, Image Vol.3 No.3

Secondary Movement Disorder in a Case of Diphtheric Encephalitis: Clinical and Neuroimaging Features of a Rare Association

Chinmay P Nagesh,Sanjiv C Chamraj,Vijaya Bhaskar SM,Srikanta JT 대한신경과학회 2019 Journal of Clinical Neurology Vol.15 No.3

1.53 μm luminescence properties of Er³⁺-doped K-Sr-Al phosphate glasses

Linganna, K.,Rathaiah, M.,Vijaya, N.,Basavapoornima, Ch.,Jayasankar, C.K.,Ju, S.,Han, W.T.,Venkatramu, V. Ceramurgica ; Elsevier Science Ltd 2015 CERAMICS INTERNATIONAL Vol.41 No.4

<P>Trivalent erbium (Er3+)-doped K-Sr-Al phosphate glasses were prepared and studied their spectroscopic properties as a function of Er2O3 concentration. Judd-Ofelt analysis has been carried out for 1.0 mol% Er2O3-doped phosphate glass and in turn radiative properties have been evaluated for the excited levels of Er3+ ion. The radiative lifetime for the (4)t(13/2) level was found to be higher for the present glass when compared to other Er3+-doped glasses. The Er3+-doped glasses exhibit intense near infrared emission at 1.53 mu m corresponds to I-4(13/2)-> I-4(15/2) transition as well as green emission at 546 nm corresponding to S-4(3/2)-> I-4(15/2) under 980 nm and 488 nm excitations, respectively. The emission cross-section spectrum for 1.0 mol% of Er2O3-doped glass has been evaluated using McCumber theory. The gain cross-section has been evaluated as a function of population inversion, which revealed that the lasing action would be achieved at 1.53 mu m for a population inversion about 40%. Decay curves for the I-4(13/2) level were measured and lifetimes have been determined for the studied glasses. The results indicate that the present glasses could be useful for laser as well as optical amplifiers at 1.53 mu m. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.</P>

A quasi-ballistic drain current, charge and capacitance model with positional carrier scattering dependency valid for symmetric DG MOSFETs in nanoscale regime

Vyas R. Murnal,C. Vijaya 나노기술연구협의회 2019 Nano Convergence Vol.6 No.19

This paper presents a physically valid quasi-ballistic drain current model applicable for nanoscale symmetric Double Gate (SDG) MOSFETs. The proposed drain current model includes both diffusive and ballistic transport phenomena. The model considers the important positional carrier scattering dependency effect near the source region described in terms of transmission and reflection co-efficients related to the scattering theory. The significance of carrier transport near the bottleneck source region is illustrated where the carriers diffuse into the channel at a relatively lower velocity before accelerating ballistically. The results obtained demonstrate carrier scattering dependency at the critical layer defined near the low field source region on the drain current characteristics. The proposed model partly evolves from Natori’s ballistic bulk MOSFET model that is modified accordingly to be valid for a symmetric Double Gate MOSFET in the nanoscale regime. Carrier degeneracy and Fermi–Dirac statistics are included in the work so as to justify the complete physicality of the model. The model is further extended and is shown to be continuous in terms of terminal charges and capacitances in all regions of operation. A comparative analysis is also done between the proposed quasi-ballistic model and a hypothetical complete ballistic device.