-
Influence of Barium Doping on Physical Properties of Zinc Oxide Thin Films Synthesized by SILAR Deposition Technique
Kekeli N’Konou,
Yendoubé Lare,
Muthiah Haris,
Mazabalo Baneto,
Komi A. Amou,
Kossi Napo
Issue:
Volume 3, Issue 6, December 2014
Pages:
63-67
Received:
13 November 2014
Accepted:
19 November 2014
Published:
27 November 2014
Abstract: Undoped and Barium (Ba) doped ZnO thin films were deposited on glass substrates by successive ion layer adsorption and reaction (SILAR) method using zinc acetate, barium chloride and ammonium hydroxide solution. In the present work the effect of Barium doping on structural, optical and morphological properties were investigated. Structural characterization by X-ray diffraction reveals that ZnO films are polycrystalline with wurtzite structure. SEM images showed that Ba doping influenced surface morphology and grain size was found to increase with increase in doping level. Optical analysis showed that all the films had good transmittance in the visible region. The presence of defects into ZnO films was detected through photoluminescence studies.
Abstract: Undoped and Barium (Ba) doped ZnO thin films were deposited on glass substrates by successive ion layer adsorption and reaction (SILAR) method using zinc acetate, barium chloride and ammonium hydroxide solution. In the present work the effect of Barium doping on structural, optical and morphological properties were investigated. Structural characte...
Show More
-
Characterazation of Unmodified and Chemically Modified Coal Samples by Nitrogen Adsorption at 77k, and Investigation of their Interaction with Sulphur Dioxide, (SO2), a Known Pollutant
Nadiye-Tabbiruka M. S.,
Unaye Masiya,
Salamula,
E. J.,
Obuseng V.,
Ngila J. C.
Issue:
Volume 3, Issue 6, December 2014
Pages:
68-74
Received:
25 November 2014
Accepted:
4 December 2014
Published:
18 December 2014
Abstract: Samples of modified and fresh coal from Morupule, in Botswana, were characterized by nitrogen adsorption at 77 K and found to be micro porous materials, with the modified sample having a higher specific surface area (SBET = 282.0 m2/g) which is 19 times that of the original sample. Modification by activation increased the average pore radius slightly. Interaction of the coals with sulphur dioxide, a known pollutant, was investigated through its adsorption at various temperatures to facilitate the determination of isosteric heats of adsorption. The values obtained indicated physical adsorption of the pollutant indicating the possible reuse over and over again to trap and remove the pollutant in gaseous phase. Results from elemental analyser show that Morupule coal contains 68.8%±5.0% carbon.
Abstract: Samples of modified and fresh coal from Morupule, in Botswana, were characterized by nitrogen adsorption at 77 K and found to be micro porous materials, with the modified sample having a higher specific surface area (SBET = 282.0 m2/g) which is 19 times that of the original sample. Modification by activation increased the average pore radius slight...
Show More
-
Electrical Property of Laser-Sintered Nanopastes with Reduced Metal Nanoparticles Prepared by Laser Ablation in Liquids
Taku Saiki,
Yukio Iida,
Kennan Ri,
Marina Yoshida,
Yuuki Koga
Issue:
Volume 3, Issue 6, December 2014
Pages:
75-88
Received:
1 December 2014
Accepted:
9 December 2014
Published:
18 December 2014
Abstract: Reduced iron, aluminum, copper, and magnesium nanoparticles were produced from iron oxide (Fe3O4), aluminum oxide (Al2O3), copper oxide (CuO), and magnesium oxide (MgO) powders by using laser ablation in liquids, and nanopastes were synthesized with the reduced iron, aluminum, copper, and magnesium nanoparticles. The nanopastes were sintered by using a continuous-wave fiber laser in air atmosphere. The laser-sintered nanopastes consist of polycrystalline metal. The structures of the laser-sintered metal nanopastes were analyzed by SEM and EDX, and their resistivities were evaluated by four-terminal method. The metal nanopastes sintered by hot plate have 2.5- to 11-times-higher resistivities than those of common metals fabricated in blast furnaces. Moreover, the laser-sintered metal nanopastes have 9.5- to 45-times-higher resistivities than those of common metals fabricated in blast furnaces.
Abstract: Reduced iron, aluminum, copper, and magnesium nanoparticles were produced from iron oxide (Fe3O4), aluminum oxide (Al2O3), copper oxide (CuO), and magnesium oxide (MgO) powders by using laser ablation in liquids, and nanopastes were synthesized with the reduced iron, aluminum, copper, and magnesium nanoparticles. The nanopastes were sintered by usi...
Show More
-
Orientational Behavior of Liquid-Crystalline Polymers with Amide Groups
Genichiro Shimada,
Masanori Nata,
Shiori Tomitaka,
Seiji Ujiie
Issue:
Volume 3, Issue 6, December 2014
Pages:
89-93
Received:
7 December 2014
Accepted:
25 December 2014
Published:
6 January 2015
Abstract: Liquid-crystalline polyacrylamides with mesogenic side-chains were synthesized by the radical polymerization of a mesogenic acrylamide derivative. Their thermal properties and orientational behavior were examined by polarizing microscopy, differential scanning calorimetry, temperature-variable IR, and X-ray diffraction measurements. The liquid-crystalline polyacrylamides containing secondary amide groups formed smectic A and smectic B phases during heating and cooling processes. The glass-smectic B, smectic B-A, and smectic A-isotropic phase transition temperatures increased with increasing molecular weight. The liquid-crystalline polyacrylamide showed higher phase transition temperatures than a liquid-crystalline polyacrylate, in which the secondary amide group was replaced with an ester group. The X-ray diffraction pattern of a smectic B-oriented sample of the liquid-crystalline polyacrylamide consisted of sharp inner and very sharp outer reflections. The very sharp reflection in the wide-angle region of the X-ray diffraction pattern indicated the formation of hexatic packing within the layer. The relationship between the layer distance and the extended mesogenic side-chain length suggested that the liquid-crystalline polyacrylamide formed an interdigitated bilayer structure. The IR spectra of the liquid-crystalline polyacrylamide exhibited that the number of hydrogen bonds between the secondary amide groups decreased with increasing temperature. In the liquid-crystalline polyacrylamide, smectic A and smectic B phases, with enhanced thermal stability, were formed through the formation of hydrogen bonds between the secondary amide groups.
Abstract: Liquid-crystalline polyacrylamides with mesogenic side-chains were synthesized by the radical polymerization of a mesogenic acrylamide derivative. Their thermal properties and orientational behavior were examined by polarizing microscopy, differential scanning calorimetry, temperature-variable IR, and X-ray diffraction measurements. The liquid-crys...
Show More
