Vol 9, No 4 (2010)

Spatial motion of an uncontrolled spacecraft around its center of mass is considered, the restoring aerodynamic moment of the spacecraft being described by an odd Fourier series in the angle of attack with the three first harmonics. Analytical formulas are deduced for the action integral along seperatrix, expressed, in terms of elliptic integrals of the first, second and third kind and of elementary functions. The moments of transition between various phase planes are determined. Formulas for determining the probability of capture into any region are deduced. The moments of additional equilibrium state appearing on the phase plane are determined. The analytical condition that determines the initial angular velocity ensuring the absence of additional equilibrium states ou the angle of attack in the given time interval is specified.

The paper deals with the planar motion of an uncontrolled axisymmetric spacecraft around its center of mass under the influence of the gravitational moment and the restoring aerodynamic moment. The restoring aerodynamic moment of the spacecraft is described by an odd Fourier series in the angle of attack with the two first harmonics. The evolution of phase trajectories is studied on the basis of analyzing the action integral. The evolution of the phase trajectories is caused by the descent of the spacecraft from a low circular orbit due to the atmospheric deceleration. The moments of transition between various areas of the phase plane are determined. For the cases of motion, when, intersecting the separatrix, the phase point may fall into various oscillation regions, the formulas for determining the possibility of capture into any region are found.

An algorithm of smoothed wind profile calculating on the basis of the data of atmospheric sounding before the carrier rocket launch has been developed. A method of using design smoothed wind profile in the carrier rocket first stage ascent program for the purpose of providing the controllability under intensive wind perturbations.

The paper analyses flight dynamics on the basis of coupling and coherence between the parts of a complex dynamic system – small artificial Earth satellite – in the circular orbit using gyroscopic dampers arranged according to the “V-roll” scheme as dampers of their natural oscillations.

The physical essence of the energy optimality criteria and their interrelation with the strength balance is shown from the common point of view. The dualism of the elastic potential constancy requirement is shown. A. A. Komarov’s proof of optimization algorithm convergence has been justified theoretically on the basis of energy optimality criteria. Problems arising in the practical realization of the theory are identified.

The paper deals with variations in free cross-sectional areas of phases of double-phase flows under changes of their rate of flow. Two nomograms are presented which help to find free cross-sectional areas of both phases according to both rate-of-flow and velocity characteristics of double-phase flows.

Multi-scale complex failure analysis of aero engine compressor disks has been performed which includes microfractographic observations and 3D finite element crack analysis. Fracture origins and crack growth period have been determined. The analysis has been verified by the data of crack growth direct observations.

The paper deals with the results of testing blades of turbines with a vertical axis of rotation, namely the definition of their aerohydrodynamical characteristics. Four models of blades were tested: the first model of the blade represents a semi ellipse with a semicircumference inserted in a concave part of the semi ellipse without a stabilizing plane; the second model represents a semi ellipse with a semicircumference inserted in a concave part of the semi ellipse with a stabilizing plane the width of which is equal to of the diameter of the semicircumference; the 3^rd model is a semi ellipse without a stabilizing plane; the 4^th model is a semi ellipse with a stabilizing plane.

Principles of realization of proactive technologies of aircraft maintenance are reviewed in the article. The basic axioms of the task of controlling the hydraulic system condition by fluid parameters are formulated. A model of fluid contamination control is described.

The results of mass-spectroscopic and X-ray spectrometry methods of diagnostics of laser plasma produced by the radiation of a laser with a controlled function of mutual coherence are presented. The comparison of these two methods shows that the X-ray spectrometry method yields the most reliable information and high speed of its processing.

A method for design of refractive optical element producing the prescribed irradiance distribution with large angular dimensions from extended light source is presented. The method is based on the gradient optimization of the refractive surface represented as a bicubic spline in spherical coordinates. The secondary LED optic that produce uniform irradiance distribution in the rectangular region extended light source is computed. The energy efficiency of the optical elements is more than 75 %; the non-uniformity of the generated irradiance distribution is less than 10 %.

This paper deals with the implementation of the vector FDTD-method for solving of combined Maxwell’s equations on GPU. The implementation of the algorithm for two-dimensional problem on graphics processor NVIDIA GeForce GT 240 using CUDA-technology demonstrates computational speedup in 42.9 times as against with computations has been made on central processor  Intel Core Duo E6500. The future prospects of mesh domain decomposition application are considered in this article for the implementation of the vector FDTD-method on GPU.

In this paper analyzes the main methods for rapid assessment of surface cleanliness of dielectric substrates. Shown that the most convenient for the rapid assessment of surface cleanliness is a device based on the method by measuring tribometer sliding friction coefficient. The device is characterized by easy-to-use design, the short duration of the measurement process and, as will be shown below, does not require for their calibration of the reference surfaces and clean the surface of the indenter probe-specific technologies.

When illuminated by a linearly polarized light, a high-aperture binary bi-axicon allows one to redistribute the axial contribution of different electric vector components, ensuring a maximal value of the longitudinal component and a minimal value of the transverse component on the optical axis. Such an asymmetric axicon for the wavelength 10.6 µm is fabricated on a silicon substrate using a lithography technique with plasma-chemical etching. Off-axis diffraction patterns were obtained experimentally through diaphragm-aided scanning of the focal plane.

The calculation of the DOE, which forms an image of the strip with a directional phase gradient along it, based on optical vortex is considered. It is shown, that the increase of the singularity of the optical vortex increases the length of the strip, but decreases it’s effectiveness. The schemes and the results of experiments on the formation of images, as well as trapping and manipulating particles computed in progress and manufactured on the glass DOE, are presented.

The results of calculation of different modeling methods of radiation propagation calculation after a zone plate made of a Cu and Si are shown in the article. The modeling methods are one-dimension Fresnel transformation, one-dimension non-paraxial propagation method (angle spectrum of flat waves), two-dimension integral of Rayleigh-Zommerfeld, RSoft BeamProp software (RSoft design froup, USA). It is shown, that all four methods give results close each other in the focal plane.

We discuss results of calculation  focusing diffractive optical elements (DOEs). This elements generate light  beams that have predetermined amplitude-phase distribution which can be used for assemblage of microsystems. Also results of experiments on formation of such light fields by means of the binary spatial modulator are presented.

Researches on resolution improvement at use of a spatial filtration are given. Spatial filters such as Toraldo, the vortex phase plate, the shadow filter are used. Also for reduction of a spot of confusion it is used conical axicon. Results of experiments are given at use of the above-named filters. Efficiency of a spatial filtration for resolution improvement is shown.