T. Kriz

Practical application of electrical impedance tomography and electrical resistive tomography

Usage of electrical impedance tomography and electrical resistance tomography will be in the article. The electrical impedance tomography is a widely investigated problem with many applications in physical and biological sciences. Medical imaging can be used primarily for the detection of pulmonary emboli, non-invasive monitoring of heart function and blood flow, and for breast cancer detection. Electrical resistive tomography is use in the geophysical imaging is used for searching underground conducting fluid plumes near the surface and obtaining information about rock porosity or fracture formation. Another application of electrical impedance tomography is for example in non-destructive testing and identification of material defects like cracks or identification of corrosion in production materials. The principle of electrical impedance tomography and Electrical resistive tomography is based on the back image reconstruction, which is highly ill-posed inverse problem. The aim of both methods is to reconstruct, as accurately and fast as possible, the internal impedance or conductivity distributions in two or three dimensional models.

The NQR RF decoupler construction based on transformer

This paper will present some experiments with improving one of crucial parts of nuclear quadrupolar resonance (NQR) spectrometer, the RF decoupler. This part decouples the high power rf excitation signal from receiver port of low detected signal preamplifier. In the position of decoupler usually some LC filters and back-to-back diodes are used. We have tested rf impedance transformers of different types in rf decoupler construction, suitable for our experimental NQR spectrometer with the working frequency range from 0.5 to approximately 50 MHz. Obtained results show very good applicability of this transformers in NQR circuitry. The measured impedance and transition times between on and off state of the proposed decoupler will be discussed in this paper.

Diagnosing brain tumors with MRI

The present paper discusses the improvement of accuracy in overall diagnostics related to brain tumors. The proposed measures include, for example, maximizing the use of image modifications and decreasing the radiation doses received by a patients body. The wider project is centered on the diagnostics of pathological tissues in the brain; it describes and compares the classification and identification of particular brain tumors.

The statistical evaluation of MRI data of a plant tissue

The authors present a statistical evaluation of the MRI images of a plant tissue. Therefore, we compare the commonly used MRI contrast and looking for the best contrast to evaluation of MRI data of a plant tissue. The acquired images are classified in terms of the signal-to-noise ratio, intensity difference and steepness of the edges. We focused on the manual evaluation of the statistical data in the area of the plant tissue.

Numerical models of a graphene coaxial line

The aim of this paper is to present novel research in special numerical models of a coaxial line used for nanoelectronics. These models can be advantageously utilized in the evaluation of electromagnetic parameters, thus helping researchers and designers to solve problems related to nanoelectronics, sensors, and related components. The first of the models of a large periodic structure is designed to test electromagnetic wave propagation within a coaxial line based on a graphene composite. According to the interpretation of the results, basic design changes will be prepared for experimental fabrication of a functional sample. In the described context, the authors also introduce the results of a numerical analysis of the investigated simple nanoelectric line.