The basic concept, development and application of the photoacoustic elastic bending method are given. The photoacoustic effect as a function of modulation frequency including the elastic bending contribution to the photoacoustic signal is investigated. The theoretical model for a typical detection configuration was given and the relations for elastic bending and photoacoustic signal were derived by the dynamic theory of the thin plate. The applications of the PA elastic bending method in investigation of thermal and electronic transport processes in semiconductors, plasmaelastic and thermoelastic effects, metal-semiconductor structures and ion-modified layers were presented.

The analysis of the effective surface permittivity which unambiguously characterizes the piezoelectric material features is presented. The use of the effective sjurface permittiveity singificantly simplifies the theoretical analysis of the interdigital transducer. It enables the transformation from the complex continuum mechanics problem to the field theory area. The calculations of the complex effective surface permittivity of selected types of dielectric material applied as a basis for the surface acoustic wave devices are presented. The calculations results can be used to estimate the band of the possible bulk waves. Currently it is one of the most crucial problem of the surface acoustic wave devices. The example of the experimental filter with the distorted frequency characteristics described by the imaginary part of the effective surface permittivity is presented.

The 35 th Winter School on Wave and Quantum Acoustics was held in Ustroń, a small town in Beskidy Mountains.For the second time the School was organize in a form of three workshops:2 nd Workshop on Acoustoelectronics and Optoelectronics, 2 nd Workshop on Molecular and Quantum Acoustics, 11 th Workshop on Photoacoustics and Thermal Wave Methods (former Workshop on Photoacoustics and Photothermics).The idea of partially independent workshops has been proven during 34 th Winter School.Because of broad subject area of the school many participants prefer to take part only in selected sessions.Moreover, workshops are addressed to rather homogeneous, smaller groups of specialist and give better opportunities for discussions and direct contacts.Typically a programme contains review lectures presented by experienced researchers and shorter contributions devoted to new, original results or works being realized.Very important part of each session is a discussion, where specialist can comment presented results, propose alternative solutions or discuss new ideas.Frequently problems mentioned during a session are discussed during informal meeting.

Speeds of ultrasound and densities were measured in binary solutions of 2-methyl-1-propanol in hexane and in cyclohexane at 293.15 K in the whole concentration range. The results of the measurements in connection with literature data were used to calculate isothermal compressibility coefficients and isochoric molar heat capacities for the pure components. They were also used for finding out molar volumes, adiabatic compressibilities, free volumes and free intermolecular lengths for the mixtures under test. The composition dependences of excess molar volume, adiabatic compressibility and excess free volume were compared and discussed in terms of free intermolecular length, space-filling ability and other factors affecting the self-association of 2-methyl-1-propanol and entropy effects connected with structural changes of non-polar solvents accompanied solvation processes.

In this paper the authors concern the problem of determination of thermal properties of the object realized basing upon the results of photoacoustic measurements in pulse modulation mode. Due to high dependency of broad-band signal upon the parameters of experimental setup and very low noise-to-signal ratio of the signal, such an analysis can be done only in the frequency domain basing upon contrast frequency characteristics. The authors see at least two necessary conditions of correctness of such an analysis, which are as following: 1) the reduction of the influence of linear distortions on measured values, 2) lack of non-linear distortions.

The paper represents a brief overview on theoretical and experimental investigations of feedback acousto-optic systems carried out in Moscow State University in recent years. These systems are of great interest by reason of their complicated and intriguing behavior as well as in view of novel applications in optical information processing.

The study of archaeological analogues is necessary to improve the knowledge on the long-term corrosion of low carbon steels that could be used in concrete to build the structures of nuclear waste storage facilities. The long-term corrosion system was previously described as a multi-layer pattern made of the Metal, the Dense Product Layer (constituted of goethite with magnetite and/or maghemite marblings -DPL), the Transformed Medium (TM) which is an interphase between the Dense Product Layer, and the last layer, the Binder. As mainly constituted of goethite, a non-conductive phase, and assuming that the DPL pores are saturated with water, corrosion kinetic could be limited by oxygen diffusion in the water of the pores. Moreover, anodic and cathodic reactions should occur at the Metal/DPL interface. This last hypothesis was verified labelling oxygen precipitation sites with an oxygen isotope ( 18 O) and observing an increase of oxygen isotopic ratio at the M/DPL interface. Then, to validate the hypothesis of a diffusion control of corrosion kinetic, some investigations were performed on diffusion properties of oxygen in the DPL. For this purpose, the oxygen apparent diffusion coefficient was evaluated using diffusion cells made with DPL sampled on archaeological analogues. Then, thanks to Faraday law, it was possible to evaluate instantaneous corrosion rates (less than 0.1 μm/year). The compatibility of these rates with those obtained considering the quantity of 18 O precipitated in corrosion products was discussed. Nevertheless, even if oxygen diffusion is probably the limiting factor on iron corrosion in the very specific case of water saturated media, the hydrometry of the DPL during the life time of the object and the influence of this hydrometry on corrosion mechanisms have to be verified. Moreover, several questions were raised by TM formation and growth. Was this layer formed dissolving/precipitating corrosion products from the DPL? Unfortunately, thermodynamical data and results from our experimentation show that iron quantity obtained by this mean is not sufficient to explain TM thicknesses observed and, so far, TM formation mechanisms are still to be identified.

Planar optical waveguides in which some range of the waveguide has been modified by depositing on it a layer of some other dielectric, are called composite optical waveguides. Such a structure is based on planar waveguide obtained by means of ion exchange K + -Na + on a glass, and covered by an adequately profiled dielectric layer. This kind of structure is of much interest due to considerable possibilities of taking measurements, which may contribute to a further development of optoelectronic sensor. Especially required are sensor systems in chemistry, biochemistry, biotechnology, and others. Testing of the properties of composite layers constitute a continuation of investigations concerning the construction of interferometers, witch are very sensitive, cheep and easy to be produced.

Carbon deposits formed on the catalysts' surface is characterized by the different properties. This depends, among others, on the temperature of the catalytic reaction conducted. Application of FT-IR/PA (Fourier transform infrared photoacoustic) spectroscopy allows to examine the carbon deposit forms created during the reaction. Samples of the commercial KUB-3 catalyst (Ni-NiO/Al 2 O 3 ) taken from the industrial bed after three-year continuous work (applied for the hydrogenation of benzene) were characterized by means of FT-IR/PAS.

In the context of the prediction of the long-term behaviour of reinforced concrete structures involved in the nuclear waste storage, the corrosion mechanisms of steels have to be assessed. When mild steel rebars are embedded in concrete, the chemical environment of the reinforcement is progressively modified, due to the carbonation of the concrete matrix. This modification leads to the variation of iron oxides properties formed at the steel/concrete interface, and the active corrosion can be initiated. The aim of this study is to evaluate the passivation behaviour and to provide insights into the depassivation of mild steel in concrete pore solution. In a young concrete, due to the alkalinity of the interstitial solution, steel reinforcement remains passive. Immersion tests of mild steel substrate in various alkaline solutions (from pH 13 to 10) have been performed. Due to the low thickness of the corrosion layers formed, X-ray photoelectron spectroscopy has been used to characterize them. In the passive domain, the corrosion products are similar for the various solutions. The corrosion layer is composed of a mixture of Fe 3+ and Fe 2+ . A similar approach is used to determine the depassivation mechanism. The effect of various components such as carbonates, sulfates and silicates resulting from the dissolution of minerals of cement during the carbonation process is investigated. In addition to the surface analysis, the evolution of the electrochemical behaviour as function of the solution nature (pH) is evaluated with the help of electrochemical measurements (free corrosion potential, cyclic voltamperometry).