RNDr. Ilona Ali Bláhová, Ph.D.

The easy and fast detection of drug content and concentration levels is demanded in biological research as well as in clinical practice. Here we study on microscopic level how nanodiamonds and gold nanoparticles interact with a multifunctional drug molecule directly on a biosensor surface. The sensors are made of interdigitated Au electrodes coated by 5 nm hydrogenated or oxidized nanodiamonds and further combined with Au colloidal nanoparticles (size 20 nm) providing nanoscale composite (spacing 100 nm). Atomic force microscopy is employed to measure local tip-surface adhesion forces and surface topography. AFM adhesion maps show that the drug binds to all types of nanoparticles and the adhesion is also significantly influenced by the substrates on which the nanoparticles are deposited. Role of local AFM tip interaction with nanostructured surface is also discussed.

Physical characteristics of liquids and their accuracies were determined using an ultrasound resonator. For the beginning the influence of different experimental settings (different liquids, different cells, kind and area of used transducers, its position and different ways of their sticking in the cells walls) to obtained frequency spectra were studied. On the base of these experiments the proposal of an optimal experimental setting was prepared. The fluid physical property characterisation was obtained on the base of swept frequency acoustical interferometry. The positions of local frequency maxima and its widths were assessed and analysed. Sound speed, attenuation and liquid density were calculated. The accuracies of them were established. Additionally, the prepared experimental set-up was used for stu-dent's laboratory education.

Spherical resonator is usually used for excitation of physical phenomena known as single-bubble cavitation and single-bubble sonoluminiscence. It is evident that a creation of the cavitation bubble demands very specific conditions. A cell for these experiments has to have certain characteristics. Moreover characteristics of used liquid like speed of sound, density and kinematic viscosity should be known for precise description of the bubble dynamics. Described measurement method that follows is focused to determination of characteristics of used spherical resonator.

The conditions for measurements focused to single-bubble cavitation and single-bubble sonoluminiscence were prepared. Cell for these experiments was chosen on the base of eigenfrequencies determination. The obtained values were compared to values figured out on the base of mathematical model. The optimum frequency for single-bubble cavitation and single-bubble sonoluminiscence measurements was assessed. The swept frequency acoustic interferometry method was prepared for the determination of characteristics of used liquid. Liquid characteristics like sound speed, attenuation, and density can be determined. These characteristics will be used for mathematical model of single-babble cavitaion.

This contribution deals with the analyses of high power nonlinear ultrasonic waves inside a cylindrical resonator. It is not easy to describe their behaviour theoretically. Acoustic pressure was determined by an optical method and by a conventional method as well; it means that a heterodyne laser interferometer and a microphone were used for measurements. Broad spectra of acoustic pressure components inside the cylindrical resonator were measured by both methods and compared.

This paper deals with the analysis of ultrasonic waves inside cylindrical resonator. These waves behave nonlinearly, so it is not easy to describe theoretically their behaviour. Therefore, we started with an experimental determination of acoustic pressure. We chose two methods of measurement - by a microphone and by an optical interferometric probe. The data measured by the microphone and by the interferometer were compared.

In this paper a new method of uncertainty measurement of 1/3-octave noise is presented. Correctness of the method was confirmed by extensive measurements of a real 1/3-octave noise uncertainty.

The true 1/3-octave noise is not feasible. However, an approximate 1/3-octave noise is needful for analysis of the sound field. A concept of approximate expression of 1/3-octave noise, based on a fictional 1/3-octave transient sound, is outlined in this paper. Evidently, this expression is considerably uncertain. In this paper a method of uncertainty evaluation based on analysis of the 1/3-octave packets sequence is outlined.

The measurement of the directivity function of human hearing on the model of a human head and body was a part of the research of acoustic diffraction and scattering on solid obstacles. The experimental study of secondary sound fields around a solid obstacle (a sphere, a cylinder, a circular board and a model of a human head and body) had been realized before. The goal of our work was to develop a suitable measuring method and compare the results of measurements with analytical or numerical ones.

This paper deals with the analysis of ultrasonic waves inside cylindrical resonator. These waves behave nonlinearly, so it is not easy to describe theoretically their behaviour. Therefore, we started with an experimental determination of acoustic pressure. We chose two methods of measurement - by a microphone and by an optical interferometric probe. A harmonic power ultrasonic wave at a base frequency of 20.3 kHz was generated by a piston. The glass cylindrical resonator with an internal diameter of 17 mm and adjustable reflector was used. The dependence of the harmonic components of the acoustic pressure on the distance from the source of the power ultrasound was measured. The data measured by the microphone and by the interferometer were compared.

This paper deals with both theoretical and experimental determination of the transient particle velocity. Based on the Euler equation a particle velocity is expressed by means of a gradient processing of the two-channel record of the transient spherical sound wave.

Based on the Rayleigh`s integral, a transient theory of a spherical sound wave diffraction by a circular diffractor is developed. Good agreement of both theoretical and experimental diffractive curves is achieved.

In this paper, the use of the spark source impulse method of sound field excitation for measurements of secondary sound fields created around differently shaped obstacles was tested. Measurements were performed in an anechoic room, and the spark source impulse was generated by a high-capacity capacitor that with short-time discharge.

Secondary sound field is created around an obstacle when incidental wave is scattered and diffracted on the obstacle. Having the description of such a secondary sound field is important from technical point of view. For example measuring microphone, which has a cylindrical shape, affects an acoustical field that is measured. Because of this affection we can, for example, consider correction coefficients which can correct a value measured. We would like to propose different possibilities to obtain a description of secondary sound field around a cylindrical obstacle and prepare them for future usage.

Our interest in transient diffraction during recent decades has been led by the effort to eliminate a negative influence of diffraction on impulse measuring methods. In this paper an axial diffraction in a time domain is observed. Experimental examination of the axial diffraction of a transient spherical wave caused by the circular obstacle is very instructive for creation of the analytic theory of diffraction phenomena.

We have prepared the method for creating mathematical models of a secondary sound field for different shaped bodies. For preparation of this method, a spherical body was chosen because the comparison between experimental and analytical results is feasible. The obtained numerical description of secondary sound field was compared to descriptions calculated on the basis of analytical formula. A mathematical model of the secondary sound field measured was prepared, and measurements with differently shaped bodies and their mathematical models with respect to our experiences obtained up to now is being prepared.

The development of a measuring method to serve as the basis for a numerical description of secondary sound fields affected by inserted bodies has been considered. Experiments were performed in an anechoic chamber, which is the model of a free field. For testing of the measuring methods, models of rigid sphere-shaped bodies were used. The mathematical model of a received secondary sound field is presently under development. The comparrison with analytical model is also planed.

We are preparing a method for creating mathematical models of a secondary sound field for different shaped bodies. For preparation of this method, a spherical body was chosen because the comparison between experimental and analytical results is feasible. A concave spherical body made of glass was used for our experiments. Measurements were performed in an anechoic room, which is the model of a free field. The obtained numerical description of secondary sound field was compared to description calculated on the basis of analytical formula. A mathematical model of the secondary sound field measured is being prepared, and measurements with differently shaped bodies and their mathematical models with respect to our experiences obtained up to now will be prepared.

This paper deals with an application of the transient theory of the spectral densities to the 1/3-octave noise.

The paper deals with a method for measurement usually used for wind turbine noise. Some modifications of the measurement suggested in International Standard IEC 61 400-11 (Wind turbine generator systems - Part 11: Acoustic noise measurement techniques) were tested. For example, different microphone positions on a board and different mountings of a board were realized. Experiments were performed in an anechoic chamber, which is the model of a free field. The influence of scattering and diffraction on measurement was discussed. The results thus obtained were compared with the results reached by the standard measurement method, and the advantages and disadvantages were reviewed. In conclusion, an optimal measurement configuration was proposed.

Publikovaná práce pojednává o metodě měření, která je obvykle užívána pro měření hluku větrné turbíny. Byly testovány některé modifikace metody měření navrhované v mezinárodním standardu IEC 61 400-11 (Wind turbine generator systems - Part 11: Acoustic noise measurement techniques). Například byla provedena měření pro různé polohy umístění mikrofonu na desce. Měření byla prováděna v bezodrazové komoře, která je modelem volného pole. Byl diskutován vliv ohybu a rozptylu na výsledky měření a dále výhody a nevýhody daného způsobu měření.

Signals of periodically working machines, which were measured, were processed by classical methods of signal processing - Short Time Fourier Transform and Wavelet transform, and by a new method - Order Tracking Analysis. Some characteristics of processed signals and their physical interpretation has been surged. Psychoacoustical tests are in preparation; psychoacoustical indexes will be obtained by usual statistical method. On their basic the suppressions of the most disturbing frequencies will be suggested to improve acoustical properties of tested machines.

The scattering and diffraction are fenomenons which can affect resultes of acoustical measurement much. For correctins of measuring resultes the describtion of created secondary sound field is necessery. Lord Rayleigh has published the analytical solution for a sphere and the approximate solutin for a cilinder. For other shaped bodies the analytical solution do not exist. Many autors studied scattering and diffraction experimentally. In this paper published resultes are summerised. Presented study will be used for the preparation of mathematical model of secondary sound field for different shaped bodies.

The STFT is a compromise between time and frequency based views of a signals. It provides some information about both when and what frequencies a signal event occurs. The precision of obtained information is limited because it is determined by the size of the window. Wavelet transform represents the next logical step, a windowing technique with a variable-sized region. The major advantage of this method is the ability to perform local analysis - which is to analyse a localized area of a larger signal. Wavelet transform is capable of revealing aspects of data that other signal analyses miss. This transform use different functions (Morlet, Paul, DOG, Daubechies, etc.) for decomposition of a signal then Fourier transform. These functions have different properties (orthogonal-nonorthogonal, complex-real, different with, different shape, etc.).

Many researchers have tried to characterise the sound quality of violins by objective quality parameters. An experimental method described here is very similar to the technique of violin playing termed "pizzicato". A violin is placed horizontally on two supports with its string down. Small mass hangs from its string in a standard playing position. After releasing, the transient response is picked up by a Brüel&Kjar 4374 accelerometer placed on the back plate opposite to the bridge. For the first set of measurements a measuring card ADSP2115 was used for recording signals; for the second set of measurement's a Brüel&Kjar 2825 PULSE. A number of tests proved the reproducibility of excitation end measurement. Several violins of different quality were measured. Data were processed in a system MATLAB. STFT and Wavelet Transform were used for calculation of frequency spectrum and wavelet map. Characteristics which could be important for a tonal quality of a violin have also been noted.

Fourier Transform use cosine and sine functions for a description of a signal. Wavelet Transform use functions which are called "waves" or "wavelets". Wavelet Transform could describe signals varying in time very quickly better than the other transforms. Because of that this transform could be used for example for a description of a transient attack of a musical sound.

"Housle jsou jistě jedním z nejohromnějších a nejkomplikovanějších vynálezů akustiky, který lidský intelekt vymyslel pro svou potěchu", píše v úvodu své knihy C. M. Hutchins. Zkušení posluchači jsou schopni podle zvuku rozpoznat kvalitu nástroje. Mnoho výzkumníků se snažilo nalézt objektivní charakteristiky dobrých houslí. V experimentu, který je popisován, jsou housle buzeny brnkáním a vibrace se snímají akcelerometrem. Po ztracování získaných signálů jsou diskutovány výsledky.

"Housle jsou jistě jedním z nejohromnějších a nejkomplikovanějších vynálezů akustiky, který lidský intelekt vymyslel pro svou potěchu", píše v úvodu své knihy C. M. Hutchins. Zkušení posluchači jsou schopni podle zvuku rozpoznat kvalitu nástroje. Mnoho výzkumníků se snažilo nalézt objektivní charakteristiky dobrých houslí. V experimentu, který je popisován, jsou housle buzeny brnkáním a vibrace se snímají akcelerometrem. Po ztracování získaných signálů jsou diskutovány výsledky.

The tone playing qualities of a violin are based on unique combinations of an air subsystem (the cavity modes) and an air subsystem (the body modes). Two strong cavity modes and three important body modes of the violin below 1 kHz play the most important role in this quality. A simple entrance to this topic is presented.

"Housle jsou jistě jedním z nejohromnějších a nejkomplikovanějších vynálezů akustiky, který lidský intelekt vymyslel pro svou potěchu", píše v úvodu své knihy C. M. Hutchins. Zkušení posluchači jsou schopni podle zvuku rozpoznat kvalitu nástroje. Mnoho výzkumníků se snažilo nalézt objektivní charakteristiky dobrých houslí. V experimentu, který je popisován, jsou housle buzeny brnkáním a vibrace se snímají akcelerometrem. Po ztracování získaných signálů jsou diskutovány výsledky.