Some results obtained in the development of low-energy IEP forming electron and ion beams with parameters sufficient for a number of surface modification technologies are presented.

Keywords: low-energy beams, electron source, electrode structure.

V.A. Gruzdev – Polotsk State University, Novopolotsk, Belarus

V.G. Zalesski – Polotsk State University, Novopolotsk, Belarus

P.N. Soldatenko – Polotsk State University, Novopolotsk, Belarus

An original design of a selective high-efficiency receiver on the basis of the Schottky diode with beamed outputs is proposed. It is shown that the optimization of the sizes of its elements and location of the periodic lattices in the layer of elastic dielectric lead to the reflection losses –38 dB, conversion efficiency 97% and resonance frequency detection of 36,5 THz.

Keywords: terahertz radiation, low-barrier zero-bias Schottky diode, layer of the elastic dielectric, bulk conductivity, n⁺-layer, epitaxial layer of n-type.

A.K. Esman – B.I. Stepanov Institute of Physics of National Academy of Sciences of Belarus, Minsk, Belarus

V.K. Kuleshov – B.I. Stepanov Institute of Physics of National Academy of Sciences of Belarus, Minsk, Belarus

G.L. Zykov – B.I. Stepanov Institute of Physics of National Academy of Sciences of Belarus, Minsk, Belarus

Polarization-independent acousto-optical modulation of the nearly-non-diffracted Bessel light beams (BLB) of infrared spectral range, traveling at the vicinity of tellurium optical axis on the slowly shear ultrasonic waves is investigated. It is shown that less dependency of diffraction efficiency of BLB from the light polarization taken place under any ultrasonic intensity for XZ-cut of tellurium crystals. Polarization-independent modulation of BLB under the Bragg diffraction by ultrasound in YZ crystal plane on the shear ultrasonic wave polarized under –63⁰ to Z axis in a YX plane is stated.

Keywords: ultrasonic wave, light diffraction, gyrotropic crystal, Bessel light beam, acousto-optical diffraction, infra-red radiation.

G.V. Kulak – I.P. Shamyakin Mosyr State Pedagogical University, Mozyr, Belarus

G.V. Krokh – I.P. Shamyakin Mosyr State Pedagogical University, Mozyr, Belarus

T.V. Nikolaenko – I.P. Shamyakin Mosyr State Pedagogical University, Mozyr, Belarus

P.I. Ropot – I.P. Shamyakin Mosyr State Pedagogical University, Mozyr, Belarus

Thermooptic sound generation by Bessel light beam (BLB) in the naturally-gyrotropic two-layer superlattices for the case of registration of the resulting signal by gas-microphone cell method is investigated. It was found that the rate of energy dissipation of the TE-mode BLB essentially depends on the radial coordinate , dissipative parameters of the superlattice the relative thinkness of the sample as well as BLB taper angle . It is shown that the change in the amplitude of the photoacoustic signal in gyrotropic super-lattices is achieved through the formation TE- and TH-modes BLB by using axicon with an adjustable cone angle.

Keywords: photoacoustic effect, gyrotropic superlattice, Bessel light beam, energy dissipation rate, amplitude of the photoacoustic signal, Bessel function, heat equation.

G.S. Mityurich – Belarusian Trade and Economics University of Consumer Cooperatives, Gomel, Belarus

E.V. Chernenok – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus

V.V. Sviridova – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus

A.N. Serdyukov – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus

The features of the shape of lenticular twins, twin interlayers, as well as secondary wedge-shaped twins in a single crystal Ni₂MnGa are studied. The mechanisms of exposure to each other twins with different twinning systems are analyzed. It has been established that at the boundaries and vertices of twins the wedge-shaped counterparts of the second order are formed.

Keywords: twinning, shape memory, magnetic alloys.

O.M. Ostrikov – P.O. Sukhoi Gomel State Technical University, Gomel, Belarus

E.V. Shmatok – P.O. Sukhoi Gomel State Technical University, Gomel, Belarus

The method of stabilization of light-modulating responses of electrooptic Fabry – Perot modulator is considered. The method uses modulator with two equal resonators placed in equal thermal conditions in which the opposite phase shift of interfering waves is performed.

Keywords: electrooptic effect, amplitude modulation, phase modulation, multibeam interference, Fabry – Perot modulator, broadband radiation.

V.A. Pilipovich – B.I. Stepanov Institute of Physics of NAS Belarus, Minsk, Belarus

V.B. Zalesski – B.I. Stepanov Institute of Physics of NAS Belarus, Minsk, Belarus

A.I. Konojko – B.I. Stepanov Institute of Physics of NAS Belarus, Minsk, Belarus

V.M. Kravchenko – B.I. Stepanov Institute of Physics of NAS Belarus, Minsk, Belarus

C.A. Reshikov – B.I. Stepanov Institute of Physics of NAS Belarus, Minsk, Belarus

Using the approximation of spherical symmetry and correct physical radial behavior the density function is simulated in several analytical forms. On this basis the density function generalized form for layered structure is proposed. Masses of terrestrial planets are calculated with averaged characteristics. The possible application of simulation results is evaluated.

Keywords: density function, spherical layer, hypergeometric function, gamma function, Heaviside step function, terrestrial planet.

G.Yu. Tyumenkov – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus

E.P. El’nikov – Gomel City Lyceum ¹1, Gomel, Belarus

E.V. Firagina – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus

The opportunity of using chiral structures as components of absorbers of microwaves has been proved. The reflecting and absorbing properties of polymer composites without chiral microelements and at their existence have been experimentally investigated.

Keywords: chiral microelements, polymer composites, microwaves, absorbing coating, radar-absorbing materials, electromagnetic screens.

Qian Songsong – Nanjing University of Science and Technology, Nanjing, China

V.A. Bannyi – Gomel State Medical University, Gomel, Belarus

A.L. Samofalov – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus

I.V. Semchenko – Prorector of Physics, F. Skorina Gomel State University, Gomel, Belarus

S.A. Khakhomov – Prorector of F. Skorina Gomel State University, Gomel, Belarus

Let be a nonempty radical formation and let be a set of primes. Conditions under which intersections of the maximal subgroups of a finite group mutually simple with numbers from indexes coincide: are investigated. The results following as consequences were established for not necessarily solvable finite groups G on intersections of the maximal subgroups without restrictions on indexes: Analogs of statements on intersections and for not necessarily radical formations are received.

Keywords: radical formations, -radicals, intersections of maximal subgroups in a finite group.

L.M. Belokon – Belarusian-Russian University, Mogilev, Belarus

By the use of multidimensional signals of impulse and discrete measuring devices an optimal observation problem for stationary and nonstationary objects is considered. Concepts of a priori and current distributions of the initial state are introduced. A realization method of positional solving of the optimal observation problem is presented on the base of disclosing loop. To accelerate the numerical computations it is suggested to use a parallelizing procedure. For the stationary objects additional accelerations of computations are achieved by recurrent equations, parallelizing procedures and the “set of weights” method. The results are illustrated by the examples of the 4th order dynamical object.

Keywords: stationary object, nonstationary object, impulse measuring devices, discrete measuring devices, observation on the principle of openable loop, on-line observation, positional solution, parallel computing, “set of weight” method.

R. Gabasov – Belarusian State University, Minsk, Belarus

F.M. Kirillova – Institute of Mathematics of National Academy of Sciences of Belarus, Minsk, Belarus

Vo Thi Thanh Ha – Belarusian State University, Minsk, Belarus

Five autonomous systems of three differential equations with quadratic right-hand side are considered. The issues of the series of convergence which represent the solution of this systems, under a certain mode of transformations, the invariance in four of the given systems and existence of three-parameter solutions with movable singular line were studied.

Keywords: essential singularity, movable singular line, area of the uniqueness of solution, Dirichlet series, abscissa of absolute convergence.

A.S. Lysiuk – Y. Kupala Grodno State University, Grodno, Belarus

Let G be a finite -soluble group. We say that a Fitting set of G is -saturated if it verifies whenever It is proved that -injector of G is a subgroup of the form where is a -saturated Fitting set, which is defined with full integrated H-function F of G, – Hall system of G, W is an -injector of and

Keywords: finite -soluble group, -saturated Fitting set, -injector.

M.G. Semenov – P.M. Masherov Vitebsk State University, Vitebsk, Belarus

Let be some partition of the set of all primes, that is, and for all We say that a finite group G is: -primary if G is a -group for some a -group if G has a set of Hall subgroups such that is -primary, for all and We analyze some properties of finite -groups.

Keywords: finite group, -group, -soluble group, Hall subgroup, -separable group.

A.N. Skiba – Department of Mathematics, F. Skorina Gomel State University, Gomel, Belarus

Composition factors of finite groups in which each minimal subgroup is -subnormal were defined.

Keywords: group, subgroup, minimal subgroup, -subnormal subgroup.

V.N. Tyutyanov – Gomel Branch of International University, Gomel, Belarus

P.V. Bychkov – F. Skorina Gomel State University, Gomel, Belarus

Sufficient conditions for p-supersolubility of a finite group G=AB, where A and B have cyclic Sylow p-subgroups are received. In particular, the supersolubility of a finite group G=AB providing that all Sylow subgroups of A and B arecyclic, and the indexes of A and B in the group G are prime is proved.

Keywords: finite group, p-supersoluble group, p-solvable group.

I.K. Chirik – Gomel Engineering Institute of the Ministry for Emergency Situations of the Republic of Belarus, Gomel, Belarus

One approach determining network bandwidth of local area network for the most commonly used protocols is describes. This approach is implemented in software using a multiplatform library PCAP.

Keywords: packet sensing, bandwidth, protocols, LAN, library PCAP.

V.N. Kulinchenko – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus

O.M. Demidenko – Prorector of F. Skorina Gomel State University, Gomel, Belarus

P.L. Chechat – Department of Physics, F. Skorina Gomel State University, Gomel, Belarus