The optical properties (refractive index and optical energy gap) were studied as a function of film thickness, substrate temperature and heat-treatment temperature for structurally, compositionally and morphologically well characterized CdI2 films grown by thermal evaporation. The variation of residual stress in the film (determined by X-ray diffraction), grain size (D), refractive index (n) and optical energy gap (Eg) was observed to be different in the above three cases. Combining the results of all three experiments, the grain size dependence of n and Eg was derived. Variation of n with grain size may be attributed to the changing packing density of crystallites with grain size and its distribution consistent with SEM results. Eg was found to decrease with D non-linearly and the data fits well with the equation of the type either $E_{\rm g}(D)=3.61-0.023D-0.0034D^2$ or $E_{\rm g}(D)=3.59-\frac{0.075 D^2}{(2+D)}\cdot$ The variation of Eg with D could be attributed as due to the defect densities in the film.

We have studied the electrical conductivity of Cs vapor cells in the temperature range 190−270 °C with Cs atom density up to 3 × 1014 cm−3. Depending on these parameters controlled independently, two predominant mechanisms are shown to determine the electrical properties of the cells: wall surface conductivity and space conductivity. The latter is caused by thermionic emission of electrons from the “cesiated” surface at submonolayer coverage. This process has been studied for the case of metal (Ti) and dielectric (Al2O3) surfaces. The values of the electron emission work function are found to be 1.38–1.42 V for Ti, 1.4–1.45 V for alumina and 1.39 V for sapphire. From independent photoemission studies, we also obtain the value of 1.35–1.40 V for the work function of sapphire. Our measurement technique not requiring internal electrodes can easily be implemented for studies of charge emission and ionization, in different types of dielectric cells containing a low density gas medium.

Absorption of electromagnetic energy in human tissues is an important issue with respect to the safety of low-level exposure. Simulation is a way to a better understanding of electromagnetic dosimetry. This letter presents a comparison between results obtained from a numerical simulation and experimental data of absorbed energy by a muscle. Simulation was done using a bidimensional double-scale homogenization scheme leading to the effective permittivity tensor. Experimental measurements were performed at 10 GHz on bovine muscle, 30 hours after slaughter, thanks to the open-ended rectangular waveguide method. Results show a good agreement between measurements and simulated data.

A theoretical overview is given about the influence of the presence of the X-valley in highly doped n-GaAs on hot free-electron absorption and optical nonlinearities at 10.6 μm wavelength. The implications of the extension of the quantum-mechanical model from two to three valleys are discussed. For electron temperatures above 600 K the X-valley presence starts to be observed. We reveal that it is difficult to trace the individual contributions of different X-electron related inter- and intravalley absorption and relaxation phenomena and therefore we suggest to introduce an effective X-valley related deformation potential which is a weighted combination of all the X-valley contributions. We discuss how nonlinear optical experiments can be conducted to determine the LL-intervalley and this effective X-valley deformation potential.

A hyper-frequency method enabling to investigate into the bubble size distribution of a bubble cloud in which bubble radii are lower than the equilibrium one is displayed. It is based on analysing the void rate dissipation after the acoustic irradiation is switched off in terms of bubble dissolution. The experimental evaluation of this method has been performed in air saturated water with cavitation bubble cloud generated in a 308 kHz stationary acoustic field. The size distributions achieve range from 19 μm to 59 μm and allow to follow the influences of both the acoustic pressure and the irradiation duration on them. By taking into account the bubble coalescences occurring during the bubble rise after the end of the acoustic irradiation, the raw distributions have been qualitatively nuanced thanks to the exploitation of a probabilistic model of free bubble coalescence.

The use of spectrophotometers for the measurement of cell concentration in yeast suspension is critically discussed. Corrections are derived which take into account cell size, shape, cell aggregation (flocculation) and non linear effects related to sample thickness.

Pulsed photoacoustic spectroscopy (PPAS) provides a convenient means for in vivo and in situ monitoring of human skin properties and surface concentrations of locally applied substances, such as drugs and cosmetics. In this article, we applied the one-dimensional theoretical model of Mandelis and Royce (J. Appl. Phys. 50, 6 (1979)) to simulate the photoacoustic response of human skin and diffusion phenomena through it, for various optical absorption coefficients and sample thicknesses. This approach is analyzed through the temperature and pressure variations in the photoacoustic cell.

Using a high-resolution Si(Li) X-ray detector, the Lα, Lβ and Lγ X-ray fluorescence cross sections and the relative intensities for elements with 57 ≤ Z ≤ 71 were measured at photon incident energy of 16.9 keV. We also theoretically calculated these cross sections, and discussed the experimental results in comparison with the theoretical values. As a result, we have found that our experimental results are in good agreement with the theoretical ones.