Increased electromagnetic contamination of the environment accompanied with the amplified miniaturization of electronic components underline the issue of the reliable operation of electronics. ...Reliability is of utmost importance in special applications such as medical instruments, nuclear installations, fusion experiments, etc., where larger magnetic fields occur during operation. Therefore, the interest for insulation components that consistently protect instrumentation from overvoltage is growing. This paper deals with the effects important for the stability of a gas surge arrester, the most commonly used low-voltage component for the overvoltage protection. The effect of the magnetic field on DC and the impulse breakdown of noble gases is investigated. For the theoretical interpretation of the obtained results, the spectrum of free electron gas was determined, which enabled the evaluation of a new expression for the first Townsend coefficient. The results obtained in that way were verified through comparison with theoretically calculated results. Experiments were carried out under well-controlled laboratory conditions.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
In this work, we investigate in detail the effects due to the interaction between an electron and a stationary positive ion (or atomic hole) in the neighborhood of a surface of Fe–Si, having a strong ...plasmon peak in their electron energy loss spectra, when it is excited with synchrotron radiation. We take into account the effects due to the sudden creation of an electron and the residual holes, one in the case of X-ray photoemission spectroscopy (XPS) and two in the case of Auger electron spectroscopy (AES).
We use a semi classical dielectric formulation for the photoelectron trajectory, and we estimated the parameter rs, the radius of the sphere occupied by one electron in the solid, which is critical in order to define the electron density of the alloy. With the cited formulation, we have obtained a detailed behavior of the different contributions of the collective excitations in both processes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
In this paper, the application of three-component gas mixtures as a working
gas in Geiger-Mueller tubes was considered. In addition to the noble and
quenching gas, an electronegative gas is used, at ...the same time, as the third
component of gas mixture. This paper is mostly experimental. The experiments
are carried out on the enlarged Geiger-Mueller counter tube model. By
applying the similarity law for electric discharges in gases on the model and
commercial Geiger-Mueller counting tubes, the model was verified. The
obtained results showed that a small percentage of SF6 gas, in the working
gas, stabilize operating point of Geiger-Mueller counter tubes and reduce
dead time.
This article has been corrected. Link to the correction 10.2298/NTRP1804417E
nema
A retrospective epidemiological and diagnostic study of visceral leishmaniasis (VL) was carried out during the period 2001–2007 and included patients suspected of VL who had been diagnosed at the ...Parasitological Laboratory at the Institute for Infectious and Tropical Diseases, Belgrade. Diagnosis of VL was confirmed by microscopic examination of Giemsa-stained bone marrow (BM) smears. BM smears from 134 patients were examined; 22 cases of VL were diagnosed, the majority of which involved individuals who had been on holiday at the Montenegrian sea coast. The sensitivity of the initial BM smears was inadequate; this required the application of a serological test, adapted for routine use, for the diagnosis of VL.
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BFBNIB, DOBA, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UKNU, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A few hundred nanometre thick NiCr layers form the capacitance humidity sensor electrodes. The electrodes must have the adequate electric resistance, low mechanical tensions, proper elasticity ...coefficient in order to prevent the corruption of the NiCr-dielectric layer joint when the dielectric is saturated by the water vapour. The upper electrode must be permeable for the water vapour in order to permit the water vapour to diffuse into the dielectric. The sufficient permeability of the NiCr film is obtained by an evaporation under the deposition incidence angle of 75°. The deposition angle is defined as the angle between the normal to the substrate surface and the normal to the evaporating source. The detailed results of NiCr thin film investigation by AES, AFM and TEM are presented. The NiCr thin films are non-homogeneous and are strongly dependent on deposition conditions. A different vapour pressure of Ni and Cr during the deposition process has a dominant influence on chemical composition of the NiCr thin films. The NiCr thin film evaporated under 0° incidence angle is cracky, while the layer evaporated under 75° incidence angle has the columnar structure.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The purpose of this work was to establish the methodology for automated mass spectra recognition using neural networks.
Four different neural networks techniques were tested (backpropagation, ...improved Kohonen network, ART2 and multilayered perceptron) and compared on simulated mass spectra samples.
The testing environment set for all four neural networks spectra recognition systems showed almost the same efficiency and robustness for improved Kohonen type network as well as for the ART2 system. According to test results, both systems can be recommended for practical use in mass spectra recognition.
The stage of development of neural network methodologies is gaining on maturity. It is evident that their use is especially powerful in applications dealing with numerous parameters and their correlations (some of them unknown) such as mass spectrometry, Auger electron spectroscopy (AES), X-ray diffraction (XRD) etc.
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IJS, IMTLJ, KILJ, KISLJ, NUK, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A method for approximate analytical solution of transport equation for
particles in plane geometry is developed by solving Fredholm integral
equations. Kernels of these equations are the Green's ...functions for infinite
media treated approximately. Analytical approximation of Green's function is
based on decomposition of the functions into terms that are exactly
analytically solved and those which are approximately obtained by usual low
order DPN approximation. Transport of particles in half-space is treated, and
reflection coefficient is determined in the form of an analytical function.
Comparison with the exact numerical solution and other approximate methods
justified the proposed analytical technique.
The paper presents results of electrical breakdown time delay mean value t?d
as a function of relaxation time ? (memory curve) for krypton and
xenon-filled diodes at 270 Pa pressure. Memory curves ...were obtained for the
cases without radiation as well as in the presence of gamma and UV
radiation. It was shown that significant influence of UV radiation to t?d can
be observed for ? ? 100 ms, as well as gamma radiation for ? ? 103 ms.
Laue's distribution was also investigated for electrical breakdown time
delay data sets td, obtained for ? ? 150 ms, without radiation as well as in
the presence of gamma and UV radiation. It was shown that for all these data
sets Laue's distribution stands, except for the case when krypton-filled
tube was subjected to UV radiation. On the basis of the obtained results,
the throughout analysis was performed with the aim to investigate
possible application of these diodes as sensors of gamma and UV
radiation.
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