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[en] Steady-state photoconductivity measurements are made on thin films of hydrogenerated amorphous silicon(a-Si:H) prepared by RF glow discharge decomposition of silane(SiH4) as functions of temperature(T) and excitation light intensity(F). The photocurrent(σph) increase up to a certain critical temperature(Tm), and then decreases continuously with decreasing temperature. Also, σph is found to be proportional to Fγ, where γ ranging between 0.5 and 1 depending upon F and T. The experimental results are explained on the basis of Spear recombination model considering at least two set of localized states in addition to the extended electron and hole states. (Author)
[en] An analitical method was used in this paper or computing the temperature distribution in a damaged fuel rod. The problem is reduced to finding the solution of conductivity heat transfer equation in the fuel rod by using the criterion ''Bi''. Two kinds of nonfailure rod damages are discussed: 1) an isolated rod with an eccentricity between the fuel and the sheath; 2) a rod in a crowded microcell. The analysis of the results showed that even in an overconservative case the melting will not occur. (author)
[en] An important component of coronal loop analysis involves conflicting results on the cross-field temperature distribution. Are loops isothermal or multithermal? The Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory was designed in part to answer this question. AIA has a series of coronal filters that peak at different temperatures and cover the entire active region temperature range. These properties should make AIA ideal for multithermal analysis, but recent results have shown that the response functions of two of the filters, AIA 94 and 131 A, are missing a significant number of low-temperature emission lines. Here we analyze coronal loops from several active regions that were chosen in the 211 A channel of AIA, which has a peak response temperature of log T = 6.3. The differential emission measure (DEM) analysis of the 12 loops in our sample reveals that using data from the 131 A AIA filter distorts the results, and we have no choice but to do the analysis without these data. The 94 A data do not appear to be as important, simply because the chosen loops are not visible in this channel. If we eliminate the 131 A data, however, we find that our DEM analysis is not well constrained on the cool temperature end of six of our loops. The information revealed by our 211 selected loops indicates that additional atomic data are required in order to pin down the cross-field temperature distribution.
[en] An Infra-Red camera has been used to reduce errors and to save time, cost and efforts for measurement of temperature distribution. Because allowable ranges of major factors that affect results of the measurement of the IR camera had not been established yet, this study has been performed to investigate the major factors and ranges for the effective measurement techniques. In this study, surface temperature, surrounding humidity, distance between the camera and the surface, incident angle, and emissivity of the surface have been considered as the major factors for the experimental setup. Especially, it has been observed that the results of the IR camera have been affected by the surface emissivity greatly.
[en] The evaluation of the influence of topography on landscape radiation temperature distribution is carried out by statistical processing of digital models of elevation, gradient, aspect, horizontal, vertical and mean land surface curvatures and the infrared thermal scene generated by the Thermovision 880 system. Significant linear correlation coefficients between the landscape radiation temperature and elevation, slope, aspect, vertical and mean landsurface curvatures are determined, being —0-57, 0 38, 0-26, 015, 013, respectively. The equation of the topography influence on the distribution of the landscape radiation temperature is defined. (author)
[en] To evaluate the temperature distribution according to the size of the electrode and the thickness of the phantom using 8MHz radiofrequency capacitive heating device, various sized electrodes and phantoms were used in combination. The radii of the electrodes are 10, 15, 20, 25, 30 and 35 cm. When the thickness of the phantom was 25 cm or 30 cm, homogenous heating was achieved by using the electrode which diameter was equal to or greater than the thickness of the phantom. When the thickness of the phantom was 20 cm or less. Homogenous heating was not achieved by the larger diameter of the electorode. When the sizes of paired electrodes were not equal, the smaller electrode side was preferentially heated
[en] The temperature and incident illumination intensity dependences of steady-state photoconductivity before and after light exposure have been investigated for undoped hydrogenerated amorphous silicon (a-Si:H) films. The mobility-lifetime product for electron is ∼10-6cm2V-1 at room temperature and decreases to ∼10-8cm2V-1 by light soaking. The gap density of states in the conduction band side can be described by exponential form(exp(-E/Eo)) with Eo=34.5me V and this exponential density of gap states is not changed by long light exposure. The temperature dependence of photoconductivity shows that the electrons in conduction band edge recombine with the holes in Ey(or Do) states, resulting in the activation energy for photoconductivity to be (Ec-EA) /2=0.08 eV. The created dangling bond density by light exposure is estimated to be 4x1016cm-3 from the intensity dependence of photoconductivities. The thermal quenching phenomena are observed after light soaking, which is interpreted by the creation of dangling bonds(Do). (Author)