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121.
In the present paper, we report the compensation effect on photoconductivity of thin films of Se70Te30−x
Cd
x
(x = 2, 4, 6) alloys for high field conduction. Steady state photoconductivity measurements have been made in thin films for
different electric fields. The photoconduction was found to be ohmic at low fields and Poole-Frenkel type at high fields.
Meyer-Neldel rule (MN rule) for the pre-exponential factor (σ
ph)0 and activation energy (ΔE
ph) of photoconduction in thin films of Se70Te30−x
Cd
x
is observed in the present study. 相似文献
122.
Chalcogenide glasses are interesting materials due to their infrared transmitting properties and photo induced effects exhibited by them. Thin films with thickness of 3000 Å of the glasses Se75S25−xCdx with x=6, 8 and 10 at% prepared by melt quench technique were evaporated by thermal evaporation onto glass substrates under a vacuum of 10−6 Torr. The optical constants (absorption coefficient, refractive index and extinction coefficient) of as-prepared and annealed films have been studied as a function of photon energy in the wave length region 400-1000 nm. Analysis of the optical absorption data shows that the rule of non-direct transitions predominates. It has been found that the absorption coefficient and optical band gap increase with increasing annealing temperatures. The refractive index (n) and the extinction coefficient (k) were observed to decrease with increasing annealing temperature. 相似文献
123.
Differential scanning calorimetry was used to study glassy Se100- x Sb x (x = 2, 4, 6, 8 and 10) alloys at a heating rate of 10°C min?1 under non-isothermal conditions. An extremely large increase in the specific heat, Cp , was observed at the glass-transition temperature. It was also found that the values of Cp below and above the glass-transition temperature, Cpg and Cpe , respectively, are highly composition dependent. This indicates that the Sb additive used in the present study influences the structure of the a-Se. The variation of Cp reveals local extrema in the Se–Sb glassy system at x = 4 and x = 8. The composition dependence of both Cpe and Cpg is explained in terms of the atomic structure. 相似文献
124.
In this paper, the second order statistics of post buckling response of functionally graded materials plate (FGM) subjected to mechanical and thermal loading with nonuniform temperature changes subjected to temperature independent (TID) and dependent (TD) material properties is examined. Material properties such as material properties of each constituent’s materials, volume fraction index are taken as independent random input variables. The basic formulation is based on higher order shear deformation theory (HSDT) with von-Karman nonlinear kinematic using modified C0 continuity. A direct iterative based C0 nonlinear finite element method (FEM) combined with mean centered first order perturbation technique (FOPT) proposed by last two authors for the composite plate is extended for Functionally Graded Materials (FGMs) plate with reasonable accuracy to compute the second order statistics (mean and coefficient of variation) of the post buckling load response of the FGM plates. The effect of random material properties with amplitude ratios, volume fraction index, plate thickness ratios, aspect ratios, boundary conditions and types of loadings subjected to TID and TD material properties are presented through numerical examples. The performance of outlined present approach is validated with the results available in literatures and independent Monte Carlo simulation (MCS). 相似文献
125.
126.
We generalise a necessary and sufficient condition given by Cohn for all the zeros of a self-inversive polynomial to be on the unit circle. Our theorem implies some sufficient conditions found by Lakatos, Losonczi and Schinzel. We apply our result to the study of a polynomial family closely related to Ramanujan polynomials, recently introduced by Gun, Murty and Rath, and studied by Murty, Smyth and Wang as well as by Lalín and Rogers. We prove that all polynomials in this family have their zeros on the unit circle, a result conjectured by Lalín and Rogers on computational evidence. 相似文献
127.
Jitendra Pal Singh R. C. Srivastava H. M. Agrawal R. P. S. Kushwaha 《Hyperfine Interactions》2008,183(1-3):221-228
Nanosize zinc ferrite particles, prepared by nitrate method, were investigated by XRD, TEM, 57Fe Mössbauer spectroscopy and VSM. The average particle size in this system varies from 10 to 62 nm as the sintering temperature increases from 300°C to 1,000°C. The lattice parameters in this system are almost constant at a value of ~8.41 Å. The Mössbauer spectra of all the sintered samples show a single doublet. The Mössbauer hyperfine parameters show little change with the change of sintering temperature. The doublets are ascribed to the presence of superparamagnetism in this system, which is also corroborated by the VSM measurements. 相似文献
128.
Shweta Bhandari Avaneesh Kumar Srivastava Chhotey Lal Rama Kant 《Macromolecular rapid communications》2008,29(24):1959-1964
Composite films of poly(3,4‐ethylenedioxythiophene) (PEDOT)‐coated over functionalized multiwalled coiled and linear carbon nanotubes (CNTs) have been fabricated by a simple oxidative electropolymerization route. The nanotubular morphology of the polymer–CNT composite is responsible for the lower charge transfer impedance, lower internal resistance, and superior capacitive response in comparison to that shown by the control PEDOT film doped by trifluoromethanesulfonate ions. This facile electrochemistry exhibited by the PEDOT–CNT composite film ensues in a remarkably high coloration efficiency of 367 cm2 · C−1 at 550 nm, hitherto unrealized for PEDOT; thus demonstrating the huge potential the PEDOT–CNT composite film has as cathode for the entire spectrum of electrochromic devices.
129.
130.