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Preparation and Characterization of Cyclohexyl Moiety Toughened POSS-Reinforced Epoxy Nanocomposites
Polyhedral oligomeric silsesquioxane (POSS)-reinforced epoxy nanocomposites were prepared by reacting commercially available diglycidyl ether of bisphenol-A (DGEBA) and tetraglycidyl diamino diphenyl methane (TGDDM) epoxy resins with 1,1-bis(3-methyl-4-glycidyloxyphenyl)cyclohexane (Cy-Ep) separately and reinforced with POSS nanocluster. POSS (OAPS)-reinforced hybrid Cy-Ep-epoxy resin castings were characterized for their mechanical and morphological properties. The data obtained from mechanical studies indicated that the incorporation of nano OAPS into Cy-Ep modified hybrid systems results in improved stability. Among the epoxy systems studied, the TGDDM-based hybrid epoxy system exhibited higher values of tensile and flexural properties than that of the DGEBA hybrid epoxy system, whereas the impact strength of the DGEBA system was higher than that of the TGDDM system. The dispersion of POSS was confirmed by scanning electron microscopy and visual observation studies. 相似文献
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Layered intercalation compounds LiCo1‐xSnxO2 (x= 0 to 0.1) have been prepared using a simple combustion route method. X‐ray diffraction patterns and Laser Raman spectrum suggest that the synthesized materials had the R‐3m structure. Scanning electron images show that particles are well‐crystallized with a size distribution in the range of 50‐100 nm. The room temperature electrical conductivity of the sample increased with Sn content. For LiCo1‐xSnxO2(x = 0, 0.01, 0.03, 0.05 and 0.1), the first discharge capacity increased with increase in Sn content. Among these samples, LiCo0.95Sn0.05O2had produced the best performance of all others with a stable reversible capacity of 186 mAhg‐1 after 30 cycles. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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The inelasticity effects in the production of pion pairs in the processγγ→ππ for real photons are investigated using the partial wave dispersion relations. The total cross sections for different photon
helicities are calculated. It is observed that this process is dominated by theππ final state interaction. A prediction for S* (997) →γγ decay width is also made.
Work supported financially by CSIR, New Delhi 相似文献
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Jae Hyoung Ryu S. Chandramohan Hee Yun Kim Hyun Kyu Kim Ji Hye Kang Chang-Hee Hong Hyun Kyong Cho Hyun Don Song Ho-Ki Kwon 《Journal of Crystal Growth》2011,314(1):66-70
The effect of selective area growth (SAG) on wafer bowing of GaN-based light-emitting diodes (LEDs) is investigated. The SAG of LED structures was carried out on a silicon dioxide (SiO2) mask pattern with periodic 1000×1000 μm openings, along the sapphire 〈1?1 0 0〉 and 〈?1?1 2 0〉 directions. The morphology of a selectively-grown n-GaN epilayer was examined in relation to various growth parameters such as temperature, pressure, and V/III ratio. Under optimized growth conditions, formation of a ridge-shaped epilayer with a v-pit free smooth surface was realized. Furthermore, the ridge-shaped vertical LED structure, after the removal of the sapphire substrate by laser lift-off (LLO) showed less wafer bowing compared with conventional vertical LED structures. This is attributed to the suppression of lateral strain and dislocations during the site-selective growth process, due to a reduction in the lateral dimensions. 相似文献
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S. Chandramohan A. Kanjilal S. N. Sarangi S. Majumder R. Sathyamoorthy T. Som 《Applied Physics A: Materials Science & Processing》2010,99(4):837-842
We report on effects of Fe implantation doping-induced changes in structural, optical, morphological, and vibrational properties
of cadmium sulfide thin films. Films were implanted with 90 keV Fe+ ions at room temperature for a wide range of fluences from 0.1×1016 to 3.6×1016 ions cm−2 (corresponding to 0.38–12.03 at.% of Fe). Glancing angle X-ray diffraction analysis revealed that the implanted Fe atoms
tend to supersaturate by occupying the substitutional cationic sites rather than forming metallic clusters or secondary phase
precipitates. In addition, Fe doping does not lead to any structural phase transformation although it induces structural disorder
and lattice contraction. Optical absorption studies show a reduction in the optical band gap from 2.39 to 2.17 eV with increasing
Fe concentration. This is attributed to disorder-induced band tailing in semiconductors and ion-beam-induced grain growth.
The strain associated with a lattice contraction is deduced from micro-Raman scattering measurements and is found that size
and shape fluctuations of grains, at higher fluences, give rise to inhomogeneity in strain. 相似文献
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R. Bharathikannan A. Chandramohan M. A. Kandhaswamy J. Chandrasekaran R. Renganathan V. Kandavelu 《Crystal Research and Technology》2008,43(6):683-688
The organic NLO material 2‐nitro aniline and picric acid (2NAP) was synthesized, needle shaped single crystals of dimension 10 × 1 × 0.8 mm‐3 were grown by slow evaporation solution growth technique from the saturated solution of the title compound in chloroform at ambient temperature. The material was characterized through elemental analysis, powder XRD, 1H NMR, 13C NMR and FTIR techniques. The various planes of reflection have been identified from the XRD powder pattern. The formation of the charge transfer complex was confirmed by UV‐VIS spectroscopy. The thermal stability of the crystals was investigated using TG/DTA analyses techniques. The second harmonic generation (SHG) efficiency of the material was estimated using Nd: YAG laser as source. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Balijepalli Ramakrishna Chandramohan V. P. Kirankumar K. Suresh S. 《Journal of Thermal Analysis and Calorimetry》2020,141(6):2463-2474
Journal of Thermal Analysis and Calorimetry - A numerical analysis has been performed to examine and assess the flow and performance characteristics of the solar updraft tower (SUT) power plant. A... 相似文献
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G. Y. S. K. Swamy K. Ravikumar K. Chandramohan N.V. Lakshmi 《Crystal Research and Technology》2001,36(11):1273-1279
The title compound [[Cu(shen)]2(tp)], {[Cu(C15H17O4N2)]2}, where tp = dianion of terephthalic acid and shen = (N‐salicylidene‐N'‐(2‐hydroxyethyl ethylene‐diamine)) has been prepared and its crystal structure determined by single crystal X‐ray diffraction at room temperature. The complex crystallizes in the orthorhombic space group Pbca with four formula units in a unit cell of dimensions a = 12.298(2), b = 14.214(2) and c = 16.436(2)Å. The structure consists of binuclear units with Cu(II) ion bridged by the tp ligand in a bis‐unidentate fashion. The five coordinate Cu(II) complex adopts a distorted square‐based pyramid. A crystallographic inversion center has been located at the center of the benzene ring of the tp bridging ligand. The Cu … Cu distance inside a same binuclear entity is 11.069Å. Intermolecular aromatic ring stacking interactions were observed with the shortest atom to atom contact being 3.423Å. 相似文献
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In this paper, we report on modifications in structural and optical properties of CdS thin films due to 190 keV Mn-ion implantation at 573 K. Mn-ion implantation induces disorder in the lattice, but does not lead to the formation of any secondary phase, either in the form of metallic clusters or impurity complexes. The optical band gap was found to decrease with increasing ion fluence. This is explained on the basis of band tailing due to the creation of localized energy states generated by structural disorder. Enhancement in the Raman scattering intensity has been attributed to the enhancement in the surface roughness due to increasing ion fluence. Mn-doped samples exhibit a new band in their photoluminescence spectra at 2.22 eV, which originates from the d-d (4T1 → 6A1) transition of tetrahedrally coordinated Mn2+ ions. 相似文献