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Synthesis of Nano-Spherical Nickel by Templating Hibiscus Flower Petals
Abhijit Kar,
Ajoy Kumar Ray
Issue:
Volume 2, Issue 2, March 2014
Pages:
17-20
Received:
13 January 2014
Published:
10 March 2014
Abstract: In this study, we have represented synthesis of nano spherical nickel using porous Hibiscus rosa-sinensis petals as bio template. Synthesized Nickel nanoparticle thus characterized by SEM, TEM, XRD and wet chemical methods. Spherical Nickel particles of sized between 10nm to 200nm was observed.
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Phonon Scatterings in the Lattice Thermal Conductivity of Si_(1-x) Ge_x Alloy Nanowires: Theoretical Study
Issue:
Volume 2, Issue 2, March 2014
Pages:
21-27
Received:
14 February 2014
Published:
20 March 2014
Abstract: Theoretical investigation of the alloy concentration and temperature dependences of the lattice thermal conductivity of silicon-germanium nanowires is performed using the Steigmeier and Abeles model. Phonon scattering processes are represented by frequency-dependent relaxation time approximation. In addition to the commonly considered acoustic three-phonon umklapp processes, phonon-boundary and point-defect scattering mechanisms are assumed. No distinction is made between longitudinal and transverse phonons. The importance of all the mechanisms involved in the model is clearly demonstrated. Analysis of the results shows that: (1) alloy scattering is the dominant scattering mechanism at intermediate and high temperatures; (2) thermal conductivity is mainly depends on the alloy concentration across the full range of temperatures; (3) weak diameter dependence of thermal conductivity is observed in Si_(1-x) Ge_x alloy nanowires; (4) the roughness of nanowires depends on the alloy concentration and has a major role in decreasing thermal conductivity at low temperatures; (5) the anharmonicity parameter is not size-dependent, as compared to Si and Ge nanowires. These findings provide new insights into the fundamental understanding of high-performance nanostructural semiconductors of relevance to optoelectronic and thermoelectric devices.
Abstract: Theoretical investigation of the alloy concentration and temperature dependences of the lattice thermal conductivity of silicon-germanium nanowires is performed using the Steigmeier and Abeles model. Phonon scattering processes are represented by frequency-dependent relaxation time approximation. In addition to the commonly considered acoustic thre...
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Optical Nonlinear Absorption Coefficient of PbS Nano Particles Studied by the Z-Scan Technique
M. B. Askari,
P. Jalilpour,
F. Ahmadi
Issue:
Volume 2, Issue 2, March 2014
Pages:
28-31
Received:
15 March 2014
Accepted:
9 April 2014
Published:
20 April 2014
Abstract: Nonlinear optics to study various phenomena in which the optical properties of the material changes in the presence of light. Polarization of a material system depends non-linearity upon the strength of the applied optical field in this mediums. The Z-scan technique is the best method that by this method we can determine nonlinearity optical properties namely, nonlinearity refraction index and nonlinearity absorption coefficient in the present of high-intensity lights. It should be noted that the advantage of the Z-scan method than the other methods is, that by this method can determined the nonlinearity optical properties with precision and simultaneously. We were determined the nonlinear refraction index and nonlinear coefficient of 'PbS' that suspended in alcohol by coding in fortran environment
Abstract: Nonlinear optics to study various phenomena in which the optical properties of the material changes in the presence of light. Polarization of a material system depends non-linearity upon the strength of the applied optical field in this mediums. The Z-scan technique is the best method that by this method we can determine nonlinearity optical proper...
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