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S. Natarajan B.R. Pai R. Rajaraman C.S. Swaminathan K. Nagarajan V. Sudarsanam D. Rogers A. Quick 《Tetrahedron letters》1975,16(41):3573-3576
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Photoluminescence measurements are used to investigate the nature of the surface layers formed on n+ Si-doped and semi-insulating Cr-doped GaAs substrates after heat-treatment at 780–830°C in H2 or He flow. At 5.5 K the heat-treated n+ substrates exhibit a band near 1.44 eV while the semi-insulating substrates are characterized by a phonon assisted transition with the zero-phonon band at 1.41 eV. Both these bands are identified with donor-acceptor pair recombination. The ionization energy of both the donor and acceptor for the 1.44 eV band is estimated to be ~ 35–40 meV and it is suggested that the acceptor is SiAs. The identities of the donor in the 1.44 eV band as well as that of the centers responsible for the emission at 1.41 eV are unknown. 相似文献
198.
Experimental data on diffusivities involving organic amines diffusing in alcohols have been reported using the diaphragm cell technique. Experimental values have been compared with the predicted values by the generalized correlation proposed by Laddha and Smith. 相似文献
199.
R. Selvakumar S. Aravindh C. P. Kaushik V. G. Katarani Vidya S. Thorat Prema Gireesan V. Jayavignesh K. Swaminathan Kanwar Raj 《Journal of Radioanalytical and Nuclear Chemistry》2011,288(2):629-633
The present study involves the screening of silver nanoparticles containing carbonized yeast cells isolated from coconut cell
sap for efficient adsorption of few long lived radionuclides like 137Cs55, 60Co27, 106Ru44, 239Pu94 and 241Am95. Yeast cells containing silver nanoparticles produced through biological reduction were subjected to carbonization (400 °C
for 1 h) at atmospheric conditions and their properties were analyzed using fourier transform infra-red spectroscopy, X-ray
diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscope.
The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY)
was 19 ± 9 nm. The carbonized control yeast cells without silver exposure (CCY) did not contain any particles on its surface.
The efficiency of CSY and CCY towards the radionuclide adsorption was studied in batch mode at fixed contact time, concentration,
and at its native pH. CSY was efficient in removal of 239Pu94 (76.75%) and 106Ru44 (54.73%) whereas CCY showed efficient removal only for 241Am95 (62.89%). Both the adsorbents did not show any retention with respect to 60Co27 and 137Cs55. Based on the experimental data, decontamination factor and distribution coefficient (K
d) were calculated and, from the values, it was observed that these adsorbents have greater potential to adsorb radionuclides. 相似文献
200.
S. Swaminathan Roberta Cavalli F. Trotta P. Ferruti E. Ranucci I. Gerges A. Manfredi D. Marinotto P. R. Vavia 《Journal of inclusion phenomena and macrocyclic chemistry》2010,68(1-2):183-191
New swellable cyclodextrin-based poly(amidoamine) nanosponges, named PAA-NS10 and PAA-NS11, were synthesized by crosslinking β-cyclodextrin with either 2,2-bisacrylamidoacetic acid or with polyamidoamine segments deriving from 2,2-bisacrylamidoacetic acid and 2-methylpiperazine, respectively. Water uptake studies showed a tremendous swelling capacity of both nanosponges, forming hydrogels. Time dependent swelling experiments in various aqueous media showed that the nanosponge hydrogels were stable over a period of at least 72 h maintaining their integrity. Thermal analysis showed that the two nanosponges were stable up to 250 and 300 °C, respectively. Both PAA-NS10 and PAA-NS11 were converted to aqueous nanosuspensions using the High Pressure Homogenization technique. Bovine serum albumin (BSA) was used as model protein to study the encapsulating capacity of these new β-cyclodextrin-based PAA-nanosponges. High protein complexation capacity was observed, as confirmed by UV spectroscopy. BSA encapsulation efficiency was greater than 90% on w/w basis for both nanosponges. In vitro BSA release studies were carried out showing a prolonged release of albumin from the two swollen BSA loaded β-CD PAA-NS over a period of 24 h. 相似文献