Communications - Scientific Letters of the University of Zilina, 2010 (vol. 12), issue 2
Articles
Dielectric Properties and Breakdown of the Gate Oxide in the MOS Structure
Ladislav Harmatha, Peter Valent, Juraj Racko
Communications - Scientific Letters of the University of Zilina 2010, 12(2):5-9 | DOI: 10.26552/com.C.2010.2.5-9 
The article treats the methodology of measuring the breakdown voltage on Si-based MOS structures. Identification of defects in the thin gate oxide is performed using the Weibull statistical analysis. By comparing the current and capacitance measurements on MOS structures we determined the influence of the defect charge in the oxide upon the parameters characterizing the breakdown. A higher occurrence of defects was correlated with elevated values of the flat band voltages. This verifies the hypothesis of an increased destruction of MOS structures caused by electrically active defects arising in the course of thermic oxidation and pre-oxidation treatment...
A Theoretical Study of the Temperature Sensor Based on the LP01-LP02 Intermodal Interference in Optical Fiber with a Liquid Core
Ivan Martincek, Dusan Pudis
Communications - Scientific Letters of the University of Zilina 2010, 12(2):10-13 | DOI: 10.26552/com.C.2010.2.10-13
We theoretically propose the temperature sensor based on optical fiber consisting of fused silica and core of 2.5 μm radius filled in with toluene. In such an optical fiber the intermodal interference of modes LP01-LP02 shows a characteristic dependence of the equalization wavelength λ0 on temperature. The optical fiber sensor was theoretically investigated in the temperature range of 0-40 °C, where the equalization wavelength λ0 for modes LP01-LP02 changes from 1284.2 nm to 844.1 nm. Such considerable wavelength change with temperature favors this sensor for temperature measurements with sensitivity better than 0.1 °C.
Low-Coherence Interferometry for Measurement of Properties of Optical Components
Daniel Kacik, Norbert Tarjanyi, Ivan Turek
Communications - Scientific Letters of the University of Zilina 2010, 12(2):14-18 | DOI: 10.26552/com.C.2010.2.14-18
We present a modification of the interferometric method for the measurement of refractive index or thickness of optical devices using an easily aligned, almost all-fiber Michelson interferometer. Applicability of the method is demonstrated by the chromatic dispersion measurement of photonic crystal fiber sample. The birefringence of the optical device based on LiNbO3 obtained from the measurement of refractive indices is demonstrated and its value is determined for two different crystal samples. It is also shown that when the thickness of, for example, photopolymer material is known the refractive index of the device can be determined. The described...
Silicon Nitride Based Non-Volatile Memory Structures with Embedded Si or Ge Nanocrystals
Zsolt J. Horvath, P. Basa, T. Jaszi, A. E. Pap, Gy. Molnar, A. I. Kovalev, D. L. Wainstein, T. Gerlai, P. Turmezei
Communications - Scientific Letters of the University of Zilina 2010, 12(2):19-22 | DOI: 10.26552/com.C.2010.2.19-22
Memory structures with an embedded sheet of separated Si or Ge nanocrystals were prepared by low pressure chemical vapour deposition using a Si3N4 control and SiO2 tunnel layers. It was obtained that a properly located layer of semiconductor nanocrystals can improve both the charging and retention behaviour of the MNOS structures simultaneously. Memory window width of above 6 V and retention time of 272 years was achieved for charging pulses of 15 V, 10 ms.
Magnetic Nanoparticles for Application in Nanomedicine
Milan Timko, Peter Kopcansky, M. Koneracka, Vlasta Zavisova, N. Tomasovicova, A. Dzarova
Communications - Scientific Letters of the University of Zilina 2010, 12(2):23-29 | DOI: 10.26552/com.C.2010.2.23-29
This contribution will summarize the information about the ways of synthesizing biocompatible magnetic nanoparticles and complexes containing them and the possibility of their application in nanomedicine at magnetic drug targeting and thermal treatment of diseases by hyperthermia effect. Some procedures of the preparation of biocompatible magnetizable complexes as magnetic nanoparticles, magnetic fluids, some proteins and enzymes covalently bound to the freshly prepared magnetic nanoparticles in the presence of carbodiimide (bovine serum albumin, streptokinase, chymotrypsin, dispase, glucose oxidase), entrapment of magnetic particles into magnetoliposomes...
Some Effects Observed in the Magnetic Fluid under the Influence of Quasi-Homogeneous Magnetic Field
Julius Stelina, Ctibor Musil
Communications - Scientific Letters of the University of Zilina 2010, 12(2):30-33 | DOI: 10.26552/com.C.2010.2.30-33
The effect of homogenous external magnetic fields on the created space structure of a nanoparticle distribution in a sample of magnetic fluid was studied. A grating was formed by the interference field of two crossed Ar-laser beams. The magnetic field was formed by using two electromagnets. The magnetic field oriented parallel to strips of grating does not significantly change the shape of nanoparticle grating. Perpendicular direction of magnetic field causes redistribution of the nanoparticles and in consequence of that the perpendicular nanoparticle "quasi-grating" arised.
The Dielectric Breakdown of Magnetic Fluids
Jozef Kudelcik, Peter Bury, Vlasta Zavisova, Milan Timko, Peter Kopcansky
Communications - Scientific Letters of the University of Zilina 2010, 12(2):34-37 | DOI: 10.26552/com.C.2010.2.34-37
The development of dielectric breakdown and the DC dielectric breakdown voltage of magnetic fluids based on inhibited transformer oil ITO 100 were investigated in parallel orientations of external magnetic field. It was shown that the breakdown voltage is strongly influenced by the magnetic nanoparticles. The magnetic fluids with the volume concentration of 1% had better dielectric properties than pure transformer oil. The increase of breakdown voltage was interpreted on the base of the bubble theory of breakdown.
Analysis of Acoustic Attenuation Spectra of Lipon Glasses
Peter Hockicko, Francisco Munoz, Peter Bury, Peter Sidor
Communications - Scientific Letters of the University of Zilina 2010, 12(2):38-42 | DOI: 10.26552/com.C.2010.2.38-42
The acoustic attenuation spectra which reflect the basic features of the relaxation and transport processes of the mobile ions of investigated phosphate and oxynitride phosphate glasses are analyzed. Suitable theoretical models and mathematical fit of acoustic spectra are used for characterization of the ionic hopping motion, relaxation processes and transport mechanisms connected with the mobility of conductive ions. Results from acoustic measurements are compared with results obtained from electrical conductivity measurements.
The Effective Description of Strong Electroweak Symmetry Breaking
Mikulas Gintner, Josef Juran, Ivan Melo, Beata Trpisova
Communications - Scientific Letters of the University of Zilina 2010, 12(2):43-48 | DOI: 10.26552/com.C.2010.2.43-48
The actual mechanism of electroweak symmetry breaking remains the last unsolved part of the Standard model of electroweak interactions. We review the general requirements that all possible solutions must fulfill. Based on them the effective description of the mechanism can be formulated. We offer such a description which is a modified version of the so-called BESS model and discuss its properties.
Methods of Humidityanalysis in Transformer Oil
Miroslav Gutten, Jozef Kudelcik
Communications - Scientific Letters of the University of Zilina 2010, 12(2):49-52 | DOI: 10.26552/com.C.2010.2.49-52
To prevent failure states of transformer, we performed different types of measurements. We made measurements of a frequency dependence of capacity of test transformer immersed in tank with transformer oil. The capacity illustrates a momentary state of the measured equipment and its variations to indicate the changes in the transformer oil. Water content in the transformer oil causes deterioration of its insulation and, finally, thermal defect of solid insulation.
Patterning Techniques for Fabrication of Submicrometer Structures in Photoresist, III-V Semiconductors and PMMA
Dusan Pudis, Jarmila Kubicova, Lubos Suslik, Jaroslava Skriniarova, Ivan Martincek, Ivan Novotny
Communications - Scientific Letters of the University of Zilina 2010, 12(2):53-57 | DOI: 10.26552/com.C.2010.2.53-57
This paper presents experimental results in the field of planar periodic structures, their fabrication and analysis. We demonstrate techniques and experimental results of fabrication of two-dimensional periodic structures and their preparation in a thin photoresist layer, III-V semiconductors and PMMA - interference lithography using two coherent laser beams, nanoimprint lithography and lithography using nearfield scanning optical microscope.
Study of the Density of States Distribution in the SiO2/Si Structure
Stanislav Jurecka, Igor Jamnicky
Communications - Scientific Letters of the University of Zilina 2010, 12(2):58-61 | DOI: 10.26552/com.C.2010.2.58-61
Interface properties of Al/SiO2 /Si MOS structures with NAOS oxide layer were analyzed by the construction of the capacitance-voltage model with the interface states. Energy distributions associated with the localized states in silicon band gap were modeled by the Gaussian distribution. Energy levels of localized states and the densities of interface states were determined. The results correspond with the results of the interface states study performed by the acoustic deep-level transient spectroscopy.
Alterations in Signal Dynamics during Regulation of Airway Reflex Response
Juliana Knocikova
Communications - Scientific Letters of the University of Zilina 2010, 12(2):62-66 | DOI: 10.26552/com.C.2010.2.62-66
Regulatory airway mechanisms were studied on the basis of phrenic nerve activity which was compared during eupnea and aspiration reflex (AspR). Due to changing degrees of signal stationarity, discrete wavelet transformation enabling multiresolution analysis was performed, followed by calculation of wavelet energy and wavelet entropy parameters.The higher rate of wavelet energy was detected in lower frequency components during AspR in contrast to eupnea. Moreover, quiet inspiration is characterized by higher wavelet entropy comparing to the AspR, indicating the probability of its random character and varying degree of system disorder during transient...
The Effects of MoO3 Powder Lubrication on Tribological Properties of Sliding Pair Exposed to High Temperature
Yoshinori Takeichi, Marian Dzimko, Uwe Winkelmann
Communications - Scientific Letters of the University of Zilina 2010, 12(2):67-71 | DOI: 10.26552/com.C.2010.2.67-71
The effect of molybdenum trioxide MoO3 powder on the tribological properties of sliding pair exposed to the temperature up to 700 °C was examined. The experiment showed that MoO3 powder placed directly on the sliding surface of main tribological body influenced and reduced friction values of tested materials. Especially in a temperature range from 500 to 700 °C a clear minimum of friction coefficient around 600 °C was observed. The X-ray diffraction analysis of friction and wear tracks that appeared on specimens showed mixture of different elements which are the product generated during tribological processes at high temperature.
Proposal of Key Factors for User-Oriented Web Applications
Iveta Kremenova, Marian Galovic
Communications - Scientific Letters of the University of Zilina 2010, 12(2):72-75 | DOI: 10.26552/com.C.2010.2.72-75
The paper deals with issues regarding the identification of key-factors for a successful creation of a user-oriented web application. Described are methods of identification, sources of information and contents of each category. The categories are Search, Display, Home Page and Navigation. The categories are broken-down into a table form. The paper also presents the results of several web applications testing based on new identified key factors. The testing was performed by the Department of Communications using a sample of web pages.
An Traffic Control Method Based on the Real-Time Detector Delay
Bohang Liu, Tong Zhang, Qingbing Li, Lijuan Wang
Communications - Scientific Letters of the University of Zilina 2010, 12(2):76-80 | DOI: 10.26552/com.C.2010.2.76-80
This paper puts forward a new single intersection control optimization method based on real-time delays by using the new technology of traffic detection. With this method the delay data (including parking delay, acceleration and deceleration delays) of vehicles and speed of the vehicles at the stop bar in every cycle can be detected real-timely. Thus, we can change the cycle length, total split, yellow time and all red time according to the analysis of the reasons of delay changes so as to optimize the traffic signal timing. Compared with traditional methods, this method can effectively deal with the situation that the traffic control scheme does not...