V.B. Zamarajev, V.A. Kabanov, G.M. Morgun, and V.B. Sinitsky
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Variability of GPS Signal Characteristics in the Above-Water Layer of the Atmosphere

The paper presents the observation results on GPS satellite passages beyond horizon over sea surface. The authors consider characteristic features of signal interference under various conditions, e.g. troposphere refraction effects and sea roughness. It is demonstrated that the set point and the first lower minima of interference structure corresponds to the maximum angular variability due to refractive effects. The influence of the seasonal changes of the surface refractive index of the troposphere on the set point position is estimated.

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Ye.N. Belov, Ye.M. Zarichnyak, V.I. Lutsenko, I.V. Lutsenko, and V.G. Yakovlev
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Use of Monopulse Difference-Phase Direction Finding Method for Location of Air Targets in Active-Passive Systems with Noise-Like Signal

A possibility of air target detection is considered with the use of information about angles of arrival of signals scattered by the target "illuminated" by external source. A monopulse difference-phase direction-finder is developed and made, and preliminary data are obtained on measurement of arrival angle of rescattered signal as an airplane flights-over.

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K.V. Ilyenko, G.M. Gorbik, and T.Yu. Yatsenko1
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura Str., Kharkov 61085, Ukraine

1V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
On the Calculation of the Force Acting Upon a Moving Charge in a Cylindrical Drift Tube

The Green function method in the Coulomb verification were used to calculate analytically the scalar potential and the density of charges on the walls of a perfectly conducting cylindrical drift tube, induced by a moving low relativistic point charge. In the quasi-electrostatic approximation, the force acting on the point charge from the charges induced by it on the drift tube walls, was obtained as a function of the radial distance from the axis of the tube. Interpolation expressions for the force were built. The obtained results allow to estimate the influence of cylindrical drift tube walls, when studying the dynamics of charged particle beams moving in complex electromagnetic fields by the particle-in-cell method.

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G.A. Alexeev
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
On the Influence of Ions on the Static Potential Distribution in O-Type Devices with the Long-Time Interaction

The influence of ions of residual gas on the static potential distribution in the transverse section of the plane-parallel channel with a strip electron beam has been studied. Peculiarities of formation of the natural ion trap have been investigated depending on the parameter of the electronic charge compensation, the temperature of ionic gas, the coefficient of the channel filling by an electron beam, and the asymmetry coefficient of its arrangement. The results can be used at the design of Î-type devices with the long-time interaction.

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D.O. Mazunov
Lashkarev Institute of Solid State Physics,
National Academy of Sciences of Ukraine
41, Nauka ave., Kiev, 03028, Ukraine
Field Emission Properties of Nonstoichiometric Silicon Oxides

The emission characteristics of SiOx (x~0.3) thin film flat cathodes, produced by thermal vacuum evaporation of silicon, have been investigated. It is shown that the high-temperature annealing (>1000oC) of these films in the inert ambient gas with subsequent etching in the HF solution sufficiently improves emission properties: emission currents increase whereas the threshold voltage reduces. The explanation of the peculiarities of electron field emission from SiOx is proposed. It is demonstrated that the Fowler-Nordheim tunneling is a limitation process of the current flow under high-electric fields. Current peaks in the emission volt-ampere characteristics are revealed. Most likely, they are caused by the resonance tunneling mechanism.

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Î.V. Botsula and E.D. Prokhorov
V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine
Two-Level Resonant-Tunneling Diodes with Tunneling Anodes

A resonant-tunnelling diode with a two-level quantum well and an anode in the form of a tunnelling diode connected in the direct direction has been investigated. In this condition, the voltage-current characteristics of the diode have three region of negative differential conductivity. The generation efficiency and the frequency wave band, which is up to 1000 GHz for the parameters given in the article, have been defined for these regions.

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V.K. Kiselyov, Ye.M. Kuleshov, and V.K. Laptiy
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
Research of Terahertz-Band Gas HCN Laser with the Malter Effect in Hollow Cathode

A hollow cathode with abnormal secondary emission (Malter effect) is applied in terahertz-band gas HCN laser. Stable laser generation is obtained with the discharge gap of 0.8 m and with the voltage and current values of 660 V and 0.5 A respectively. The cathode temperature was + 20°C.

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A.V. Vichkan' and P. A. Melyanovsky
A. Usikov Institute of Radio Physics and Electronics,
National Academy of Sciences of Ukraine
12, Academician Proskura St., Kharkov 61085, Ukraine
A Phase-Frequency Method for Resonant Measuring the Complex Permittivity of Media

A phase variant of the resonance method for measuring the complex permittivity in different materials at high frequencies has been considered.

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N.V. Sheikina1, N.I. Bogatina2, and E.L. Kordum3
1V. Karazin National University of Kharkov,
4, Svoboda Sq., Kharkov, 61077, Ukraine

2B.Verkin Institute for Low Temperature Physics and Engineering,
National Academy of Sciences of Ukraine
47, Lenin ave., Kharkov 61100, Ukraine

3Institute of Botany,
National Academy of Sciences of Ukraine
2, Tereschenkovskaya St., Kiev 01001, Ukraine
Influence of Combined Magnetic Fields on the Gravitropic Response of Plants and on the Spectrum of Electromagnetic Radiation Generated by Plants during Their Growth

The impact of combined magnetic field (CMF) on the gravitropic response (GTR) of 3-day cress roots in the frequency region from 1 to 45 Hz has been investigated. Changes of the sign of GTR, its activation or inhibition, or else the inhibition of the root growth itself, were observed at some fixed frequencies. The changes are resonance dependent on the frequency. The frequencies, at which the above-mentioned effects were found, are formally coinciding with the cyclotron frequencies for ions Ca2+, K+, IAA-, ions of gibberellins, ions of abscisic acid and Cu+, as well as, with the frequencies at which the electromagnetic field radiation was observed before. Possible mechanisms of the CMF effect on GTR are discussed.

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