Effect of extinction of the texture coefficients of uranium

1983 ◽  
Vol 114 (2-3) ◽  
pp. 347-348
Author(s):  
C.N. Rao ◽  
R. Krishnan
Keyword(s):  
1997 ◽  
Vol 81 (8) ◽  
pp. 5224-5226
Author(s):  
S. C. Seol ◽  
T. Kang ◽  
K. H. Shin ◽  
T. D. Lee ◽  
G. S. Park

1986 ◽  
Vol 6 (3) ◽  
pp. 167-179 ◽  
Author(s):  
M. Dahms ◽  
H.-J. Bunge

The calculation of orientation distribution functions from incomplete pole figures can be carried out by a least squares approximation of the texture coefficients Clμν and the normalization factors Nhkl to the available experimental data. This procedure is less susceptable to instabilities due to experimental errors if the normalization factors can be calculated independently of the coefficients Clμν. In the case of cubic materials, the relationship F20 = 0 to be fulfilled by pole figure values provides an independent condition for the calculation of the normalization factor. This condition can still be improved by taking the slopes of the pole density curves at α = αmax⁡ and α = 90° into account. An economic way to consider the slope in the pole figures is to use a cubic spline interpolation.


2020 ◽  
Vol 15 (1) ◽  
pp. 101-107
Author(s):  
M. Karunakaran ◽  
L. Bruno Chandrasekar ◽  
K. Kasirajan ◽  
R. Chandramohan

This paper reported the preparation and characterization of transparent conducting oxide thin films. Undoped and doped ZnO thin films were prepared by SILAR method. The micro-structural and optical properties were investigated. X-ray diffraction patterns revealed that the prepared thin films are polycrystalline in nature and has a hexagonal structure. The micro-structural properties of prepared thin films were calculated and crystallite size tends to changes due to dopant. The texture coefficients have been evaluated and found to be greater than unity revealing high texturing of the film. Undoped and Mn-doped ZnO prefer the orientation of (002) but Ni-doped ZnO and Mn and Ni co-doped ZnO prefers (100) orientation. The transmittance spectra of pure and transition metal-doped films were plotted against UV-Vis-NIR region and found that the transmittance changes with dopant and nature of doping. The optical band gap values were found to be in the range of 3.00–3.39 eV. The optical constants such as extinction coefficient, refractive index, dielectric constant and optical conductivity were examined.


2021 ◽  
Vol 63 (3) ◽  
pp. 245-252
Author(s):  
Emine Başalan ◽  
Mustafa Erol ◽  
Orkut Sancakoğlu ◽  
Tuncay Dikici ◽  
Erdal Çelik

Abstract Titanium thin films were deposited on glass and indium tin oxide (ITO) coated glass substrates by radio-frequency (RF) magnetron sputtering under varying sputtering parameters as: power, pressure, substrate temperature and target-substrate distance. The crystalline structure, crystallite size and texture coefficients of the films were evaluated in detail. As the evaluation points out, 100 W, 1.33 Pa ambient temperature and 70 mm were determined as the optimum sputtering parameters for intended crystalline structures. Subsequently, electrochemical anodization experiments were performed via varied electrolytes and under various anodization parameters (voltage, time and electrolyte type) in a two-electrode electrochemical cell using the films obtained through the optimized sputtering parameters. The anodized samples were annealed at 450 °C for 1 h in air in order to obtain anatase transformation and the desired crystalline structure. The surface morphologies and the crystalline structures of the anodized films were evaluated through x-ray diffractometer (XRD) and scanning electron microscope (SEM), respectively. Finally, the anodization parameters for the formation of TiO2 nanotube arrays were determined as: 35 V and 35 min. in an electrolyte composed of 0.3 wt.-% NH4F – 2 wt.-% water – ethylene glycol.


2019 ◽  
Vol 1 (3) ◽  
pp. 14
Author(s):  
I. A. Khan ◽  
S. A. Hussain ◽  
A. S. Nadeem ◽  
M. Saleem ◽  
A. Hassnain ◽  
...  

<p>Polycrystalline cuprous oxide (P-Cu2O) films are deposited on Cu substrates for various (0.2, 0.3 and 0.4 mbar) oxygen pressures (OP) by thermal evaporator. The XRD pattern shows the development of Cu (200), Cu2O (200) and Cu2O (311) diffraction planes which confirms the deposition of P-Cu2O films. The intensity of Cu2O (200) and Cu2O (311) planes is associated with the increase of OP. The crystallite size and microstrains developed in (200) and (311) planes are found to be 19.31, 21.18, 11.32 nm; 22.04, 23.11, 12.08 nm and 0.113, 0.103, 0.193; 0.099, 0.096, 0.181 with increasing OP respectively. The d-spacing and lattice constant are found to be 0.210, 0.128 nm and 0.421, 0.425 nm respectively. The bond length of P-Cu2O film is found to be 0.255 nm. The crystallites/unit area of these planes is found to be 12.21, 7.46, 45.16 nm-2 and 8.21, 5.75, 37.16 nm-2 respectively. The texture coefficients of these planes are found to be 1.22, 1.26, 1.11 and 0.78, 0.74 and 0.56 with increasing OP respectively. The O and Cu contents are found to be 5.31, 5.92, 6.94 wt % and 83.01, 82.44, 80.65 wt % respectively. The thickness and growth rate of P-Cu2O films are found to be 87.9, 71.9, 65.5 nm and 17.6, 14.2, 13.1 (nm/min) with increasing OP respectively. The SEM micro-structures reveal the formations of patches of irregular shapes, rounded nano-particles, clouds of nano-particles and their distribution depend on the increasing OP. The refractive index and energy band gap of P-Cu2O films are found to be 1.96, 1.89, 1.92 and 2.47, 2.44 and 2.25 eV with increasing OP respectively.<br /><br /></p>


2007 ◽  
Vol 340-341 ◽  
pp. 829-834
Author(s):  
Yi Ping Chen ◽  
Wing Bun Lee ◽  
Sandy To

An accurate prediction of plastic anisotropy induced by initial texture in sheet metal forming operations depends on the constitutive models adopted. Models of engineering interest include both phenomenological formulations and crystal plasticity based on dislocation slip. In addition to the above two approaches that are commonly adopted in FE analysis, now an alternative is available which describes anisotropic behavior of polycrystalline sheet metals still by an analytic yield function to keep the computing time as low as possible but at the same time which also takes explicitly into account the crystallographic texture of the material to give a more precise description of plasticity anisotropy. However, the locus of such a yielding potential determined by constitutive coefficients upon invoking the rate-independent crystal plasticity may exhibit an unrealistic concave shape, which will make it impossible to obtain a convergent solution. To circumvent the difficulty, a detailed computation procedure is presented to calculate the constitutive coefficients based on rate-dependent crystal plasticity. The combination of the coefficients obtained with experimentally measured texture coefficients of an annealed FCC polycrystalline sheet metal will provide a complete constitutive characterization of the material. As an application of the calibrated model, the process of deep drawing by hemispherical punch is simulated, in which plastic anisotropy (earring) corresponding to typical texture type is observed, thus demonstrating the applicability of the coefficients found.


Sign in / Sign up

Export Citation Format

Share Document