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1.
S. Ramasamy D. J. Smith P. Thangadurai K. Ravichandran T. Prakash K. PAdmaprasad V. Sabarinathan 《Pramana》2005,65(5):881-891
The ultra high vacuum chamber was developed in the Department of Nuclear Physics, University of Madras with the funding from
DST, India. This UHV chamber is used to prepare nanocrystalline materials by inert gas condensation technique (IGCT). Nanocrystalline
materials such as PbF2, Mn2+-doped PbF2, Sn-doped In2O3 (ITO), ZnO, Al2O3, Ag2O, CdO, CuO, ZnSe:ZnO etc., were prepared by this technique and characterized. Results of some of these materials will be
presented in this paper. In solid-state207Pb NMR on PbF2 a separate signal due to the presence of grain boundary has been observed. The structural phase transition pressure during
the phase transformation from the cubic phase to orthorhombic phase under high pressure shows an increase with the decrease
in grain size. Presence of electronic centres in nanocrystalline PbF2 is observed from Raman studies and the same has been confirmed by photoluminescence studies. Al2O3 was prepared and56Fe ions were implanted. After implantation segregation of56Fe ions was examined by SEM. The oxidation properties of ITO were studied by HRTEM. As against the expectation of oxide coating
on individual nanograins of In-Sn alloy, ITO nanograins grew into faceted nanograins on heat treatment in air and O2 atmosphere. The growth of ITO under O2 atmosphere showed pentagon symmetry. The PMN was initially prepared by solid-state reaction. Further, this PMN relaxor material
will be used to convert into nanocrystalline PMN by IGCT with sputtering and will be studied 相似文献
2.
Aequationes mathematicae - The Hyers-Ulam stability of the iterative equation $$f^n=F$$ for continuous functions F was studied under the assumptions that F is a homeomorphism on its range, and the... 相似文献
3.
Critical problems of the present approach of electrolytes for Solid Oxide Fuel Cells (SOFCs) for commercialization are discussed.
Major progress is expected from the development of materials based on the “SEA (Single Element Arrangement)” concept. The
galvanic cell consists in this case basically of a single chemically homogeneous compound, which functions as electrodes at
high and low activity and as electrolyte at intermediate activities of the electroactive component.
In view of the large structural flexibility of the chemical nature of the constitutents, we explored perovskite (ABO3)-type compounds to be used as SEAs for SOFCs. Results of studies on Pr-substituted LSGM and Fe-substituted SrSnO3 perovskite-type oxides are presented. For instance, SrSn1-xFexO3-δ with x=0.1 exhibits p and n-type electronic conduction at the cathode and anode sides of the SOFC, respectively, while oxide
ion conduction prevails at intermediate oxygen partial pressures. The SEA concept is also applicable for other devices in
the field of Ionics. 相似文献
4.
N. Sankara Subramanian B. Santhi V. Veeraganesh C. Vinoth G. Murugan G. Karthik Subbaraj 《Ionics》2004,10(1-2):56-62
Present work deals with the preparation of TiO2 thin films of different thicknesses by PVD technique using an electron beam and to characterize the films for oxygen gas
detection. The films were characterized using optical transmission measurements, XRD and atomic force microscopy. From the
spectral data, the extinction, absorption coefficient and refractive index of the films are evaluated and reported. The optical
band gap energy varies between 3 and 3.68 eV. The XRD pattern confirms the formation of polycrystalline anatase structure
of Titanium with preferred orientation of (110) plane. The AFM images indicate the presence of coarse and fine grains with
uniform as well as smooth surfaces over the entire range of the analyzed surface. Response characteristics of TiO2 thin films for oxygen gas detection are studied, which indicate a low response time of 120 seconds and high sensitivity of
16 at the operating temperature 450 °C.
Paper presented at the 2nd International Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003. 相似文献
5.
6.
This paper describes the preparation and conductivity studies of polyindole–ZnO composite polymer electrolyte (CPE) with LiClO4. Polyindole–ZnO-based polymer nanocomposites were prepared by chemical method and characterized by XRD, infrared (IR), scanning
electron microscope (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The IR spectrum confirms
the intermolecular interaction between polyindole and ZnO. The significant spectral changes of polyindole and ZnO nancomposites
reveal the strong interaction between polyindole and ZnO nanoparticles. The structural morphologies of the ZnO, polyindole,
and polyindole–ZnO are obtained from SEM. The TEM image of polyindole nanocomposite shows that ZnO is embedded in polyindole
matrix. An enhanced conductivity of 4.405 × 10−7 S cm−1 at 50 °C for the CPE was determined from impedance studies. 相似文献
7.
We report the synthesis, structure, microstructure, chemical stability in H2O and CO2, and electrical transport properties of an oxide ion-conducting perovskite-related structure Ba3In2MO8 (M = Zr, Ce, Zr0.5Ce0.5). Powder X-ray diffraction confirmed the formation of a simple cubic perovskite-like structure for Ba3In2ZrO8 (a = 4.205(9) ?), Ba3In2CeO8 (a = 4.234(1) ?), and Ba3In2Zr0.5Ce0.5O8 (a = 4.285(8) ?). The increase in lattice constant is consistent with the Shannon’s ionic radius trend. Among the three samples
investigated, Ba3In2ZrO8 was found to be stable against reaction with pure CO2 at elevated temperature, while the Ce and 1:1 Zr and Ce compounds were unstable at 600 °C. Ba3In2ZrO8, Ba3In2CeO8, and Ba3In2Zr0.5Ce0.5O8 were found to be chemically unstable in H2O at about 50 °C. The bulk electrical conductivity of the samples prepared at different temperatures was found to be nearly
the same; the total conductivity (bulk + grain–boundary + electrode) seems to change with sintering temperature. Both Ba3In2ZrO8 and Ba3In2CeO8, prepared at 1,400 °C, exhibited comparable electrical conductivity of about 6 × 10−3 S cm−1 at 800 °C, which is comparable to that of conventional Y2O3-doped ZrO2 electrolyte. These compounds are very promising electroltes, provided that their chemical and mechnical stabitities are improved
without losing any ionic conductivity. 相似文献
8.
Mosquitoes have developed resistance to various synthetic insecticides, making their control increasingly difficult. Insecticides of botanical origin may serve as suitable natural control. This study evaluates the toxic potential of Ocimum canum (Sims) leaf extract and powder against Anopheles stephensi (Liston), Aedes aegypti (Lin) and Culex quinquefasciatus (Say) larval and adult mosquitoes. Larval mortality was observed after 24 h recovery period and adult smoke toxicity observed for 40 min duration at 10 min interval. Methanol extract of O. canum showed highest larval mortality against the larvae of C. quinquefasciatus LC50 = 28.3225, LC90 = 44.1150; Ae. aegypti LC50 = 43.327, LC90 = 61.249; and An. stephensi LC50 = 30.2001, LC90 = 48.2866 ppm. The smoke toxicities were 93% mortality in C. quinquefasciatus, 74% in Ae. aegypti and 79% in An. stephensi adults, respectively, whereas 100% mortality was recorded in the commercial mosquito control. Our results suggest that O. canum leaf extract and powder are natural insecticide, and ideal eco friendly approach for mosquito control. 相似文献
9.
A practical and efficient protocol for the one-pot synthesis of 2,3-substituted indoles was developed via a palladacycle catalyzed domino cyclization-alkylation reaction involving 2-alkynylanilines and allylic alcohols under mild conditions without any additives. 相似文献
10.