Home – Home – Jornals – "Philosophy of Education" 2012 number 2

One possible approach to determining the minimum set of parameters of an adaptive system whose operation is aimed at minimizing distortions arising in modern optoelectronic systems is considered. The basic source of distortions is assumed to be atmospheric turbulence, which imposes the most severe constraints on optical radiation in the atmosphere. The following basic parameters of the system are proposed: number of degrees of freedom, required frequency band (dynamic characteristic, and constraint on the spectral characteristics). Some parameters of the reference source (its size, position, and properties) are determined. The results are obtained in the form of analytical functions, which allows calculating the parameters of the adaptive system that can be used in numerous scenarios in the atmosphere.

Software for computer simulations of adaptive optics systems for atmospheric laser applications designed on the basis of advanced parallel programming techniques is developed. The adaptive optics system model includes the emitting aperture geometry and beam propagation path scenario, vertical profiles of atmospheric parameters, fast parallel split-step Fourier algorithm for solving wave diffraction and propagation equations, time-dependent models of "frozen" atmospheric turbulence with a wide range of scales, and models of the wavefront sensor and controlled deformable mirror. The hardware system for computer simulations is an off-the-shelf desktop with a 6-core 12-thread Intel® Core™ i7-970 CPU at the maximum frequency of 3.5 GHz and an NVIDIA® GeForce GTX 580 graphic accelerator with 512 universal processors operating at 1.5 GHz. Results of simulations of adaptive imaging and laser beam shaping, aimed at estimating the efficiency of adaptive optics systems on atmospheric paths are presented.

Results of an investigation and a comparison of schemes used for recording dynamic holographic gratings in a liquid-crystal spatial light modulator, which ensure grating profile asymmetrization and, thus, a significant increase in its diffraction efficiency, are presented. Three approaches are considered: digital, analog, and self-asymmetrization of the profile due to the effect of a secondary field induced in the nematic volume. It is demonstrated that the first two approaches provide recording of gratings with low spatial frequencies (several mm−1) and with an approximately equal rate of asymmetry (the potential efficiency of diffraction to the first order is 70-75 %), while the third approach provides recording of gratings with a much higher spatial frequency (hundreds of mm−1), but with a lower efficiency (about 50 %).

Results obtained at the Institute of Laser Physics Research (which is part of the Russian Federal Nuclear Center - Institute of Experimental Physics) on phase correction of pulsed and continuous wave laser radiation by closed-loop adaptive optical systems (AOS) with flexible deformable mirrors are described. With the help of a conventional AOS including a Hartmann-Shack wavefront sensor and an adaptive mirror having a 220 × 220 mm aperture, aberrations of the beam of a powerful pulsed laser facility called Luch have been reduced by an order of magnitude. The development of special software for reconstruction of singular wavefronts by the Hartmann-Shack sensor has allowed us to perform the correction of a doughnut-shaped Laguerre-Gaussian vortex laser beam in an AOS with a bimorph mirror and to focus it into a bright axial spot that drastically increases the Strehl ratio. Adaptive optical systems have been developed where the adaptive mirror control is ensured by searching for an extremum of a chosen criterion functional with the help of a stochastic parallel gradient algorithm rather than by means of wavefront measurements. Embedding of microcontrollers into the control unit has allowed us to reach an AOS bandwidth of 5 kHz and to demonstrate the dynamic phase correction of tip-tilts and higher aberrations of the wavefront caused by turbulence induced by heating of the beam propagation path under laboratory conditions.

A technique for experimental studies of the compensatory abilities of adaptive mirrors (AM) is developed and substantiated. The structure of the static residual error of correction is analyzed on the basis of experimental data for a particular AM. The theory of optimal placement of drives on the AM aperture is confirmed by experimental results.

High-resolution cameras are used as photodetectors in the image recording plane of a Shack-Hartmann wavefront sensor to record centroid coordinates which provide basic information for wavefront reconstruction. A comparative analysis is made of the accuracy of determining the centroid coordinates for CCD and CMOS cameras. The modes of instantaneous sampling and frame-by-frame accumulation of information from the cameras are considered.

This paper considers the use of an adaptive optical system for compensating aberrations of a laser radiation wavefront. Bimorph mirrors are used as correctors, and the wavefront is measured by a Shack-Hartmann sensor. Disadvantages of this adaptive system and ways to overcome them are discussed.

Problems of designing laser power transmission systems in a turbulent atmosphere using relay mirrors mounted on a stratospheric airship are analyzed. It is shown that such a system can be designed using a high-power ground-based ytterbium fiber laser, relay mirrors for transmitting highpower laser radiation, and an adaptive optical system for correcting the phase distortions of laser beams due to atmospheric turbulence. A model of a laser power transmission system was designed and tested under laboratory conditions; the tests confirmed the possibility of correcting atmospheric-turbulence distortions during guiding and high-accuracy stabilization of laser beams.
Keywords: laser power transmission systems, fiber lasers, adaptive optical system, stratospheric airships, laser relay mirror.

Physical modeling is a powerful tool for studying and testing various technical objects. In tests of an adaptive optical system (AOS), it is necessary to measure phase distortions of real objects (paths, devices, etc.) to identify real requirements and ranges of modeling. This paper presents estimates of modeling conditions and results of AOS tests under model conditions, namely, experimental results of adaptive correction of a laser radiation wavefront in a turbulent atmospheric path ~100 m long. In the experiments, the standard deviation of the wavefront and the divergence of the radiation before and during the correction were recorded. In some cases, the correction efficiency in terms of standard deviation exceeded 10 times.

Adaptive focusing of a coherent beam in a turbulent atmosphere is considered. Distributions of the mean intensity of the field of a coherent laser beam focused in a turbulent medium by means of adaptive phase correction with the use of a point reference source are calculated. The source retains a random position on the object onto which laser radiation is focused. Results of adaptive focusing with moving and motionless reference sources are compared.

Various laser systems use wide-aperture adaptive mirrors containing dozens or hundreds of drives. Thousands of high-precision measurements are based on the use of such mirrors. A simple, cheap, high-precision, and rapid method specifically designed to study the characteristics of these mirrors with a large number of degrees of freedom is described.

The propagation of laser radiation through the atmosphere is accompanied by a change in the light field under the influence of turbulence and is a random process. An adaptive system that includes a Shack-Hartmann wavefront sensor and a flexible mirror corrects distortions found at the previous time but changed before being corrected by the system. Analysis of turbulence within a given time period allows one to predict turbulent distortions at the subsequent time and use it to make a correction in the radiation phase distribution. The adaptive correction performance can also be improved by preparing the reflective surface of the adaptive mirror based on predictions of the state of the wavefront at the next time by the turbulence parameters and the transverse component of the wind speed found in previous Hartmann-Shack sensor measurements.

A method is proposed to estimate the structure constant C_n² and the outer scale L₀ of turbulent fluctuations in Hartmann sensor measurements of the wavefront parameters of a light beam transmitted through a turbulent path. The method is based on expansion of phase fluctuations within a given aperture into a series of Zernike polynomials and statistical analysis of the coefficients of this expansion. Application of the method to estimating the parameters of fluid cell turbulence yielded results which are in good agreement with estimates obtained by other methods. The paper also presents the results of modeling based on measurements of the transverse component of the wind velocity on the path determined by correlation of the local slopes at four virtual subapertures.

A method for controlling an adaptive optical system by using the intensity of laser atmospheric backscatter is studied. Mathematical modeling is used to study the generation of a control signal in a monostatic loop and, as a consequence, the range of beam focus with the closed loop. It is shown that this method of generation does not lead to beam collimation even for beams of diffraction quality.

A method for measuring the groove depth of calibration gratings is proposed which is based on measuring the spectral dependence of the the zero-order reflection diffraction efficiency. The errors of the method are determined by three main factors: the shift of the maxima of the spectrum due to the wall slope of the grating grooves, the error in setting the wavelength of the spectrophotometer, and the divergence of the light beam in the setup. It is shown theoretically that the measurement error is in the range of 0.25-1 %, depending on the fabrication technology of the grating and measuring equipment. The method was tested experimentally using commercial calibration gratings. The range of applicability of the method is discussed in terms of the geometrical parameters of the microstructure of reflection gratings and the characteristics of the spectrophotometer used.

In the article, the conceptual foundations of realization of the continuity principle in the educational sphere are considered. The relevance of its consideration is associated with the violation of the relationships of succession in the goals and objectives, contents and methods, forms of organization of education and training.

The task of socialization of the child's personality is particularly significant in our society in the period when there has occurred reorientation of the values substantially influencing  the process of  formation of the social experience of children. The way of development of our society now and in the future depends on the values that are formed by the young people today, to what extent the young children will be ready for a new type of social relations. The philosophical analysis of the essence of socialization of personality is performed  in the article.

The main factor of the stable development of the country, society, ethnos and also the individual person is education, oriented to the nature-conformity of the educational processes, training and directed development. The foundation of the nature-conforming approach to education is orientation to psychological peculiarities of students in the process of education including special ways which correspond to their specificities.

The search for effective ways to implement the ideas of humanitarization of education is in constant renewal and improvement. Therefore, by writing this article, the author aims to analyze the historical and philosophical background and development of the ideas of education humanitarization at various stages of development of philosophical thought. Based on the analysis of philosophical, socio-psychological literature on the formation of the individual, author allocates the starting basic foundations of research.

Ethnic pedagogy is considered as a type of the cultural-historical pedagogy. The cultural-historical category, which lies at the foundation of cultural-historical pedagogy, is treated as the life of a special cult in the historical space and time. These cults come out as «globalizers» in cultural-historical pedagogy, the discussion deals with the fact that in molding of personality in the specific periods of social development these or other peoples occupied the determining role, then being united with others or being decomposed, but in spite of all this they preserved their ethnic mentality.

The author has made a periodization of formation and development of the special education system of Republic of Sakha (Yakutiya) to figure out the qualitative originality of the process of formation of the correctional pedagogical help system to children with special needs in Yakutiya on the basis of historical pedagogical studying of the given process according to N. N. Malofeevs periodization of the development of the special education system of Russia, correlating with the evolution of the attitude of the state and society to the persons with special needs. The general states and distinctive features of development of the all-Russian and regional special education systems have been determined, which provides a basis for determining the conditions of the further improvement of the special education system in Yakutiya.

The Bologna process as an attempt of creation of an integrated European educational system on the principles of globalization has a progressive meaning. On the other hand, unwise and rapid realization of this process can lead to irreversible losses, the loss of specificities by the national educational systems.

The aim of the article is to substantiate the unity and interconnection of educational institutions, family and society that form the integrity of educational space in the region. The author demonstrates four basic fundamental positions of teaching and upbringing process: support of traditions which are of great vitality and creativity; further development of regional ethnic trend of national traditions; creation of ethno-pedagogical space on the basis of team-work of school, public, municipal and state organizations according to the residence; raising the level of teaching and educational process on the foundation of the factors of natural development of the person in the regional conditions.

The aim of the article is to reveal the essence and principles of nurturing the culture of international communications in the educational sphere. The author undertakes an attempt of theoretical comprehension of the phenomenon of civil consent in the context of national-ethnic problems. On the basis of theoretical analysis of the social-science literature on the problems of international communication, the author determines fundamental positions in relation to nurturing the culture of international communications of children in the preschool and school ages.

The author analyzes the content and role of cross-cultural communication at the modern stage of development of the society; the conditions of this communication prompt the person to make a choice of life philosophy. In the article, the author suggests considering possible variants of behavior of the person based on the principles of tolerance or utilitarianism. The essence of the «tolerance» concept is presented in the modern philosophical interpretations. The major principles of utilitarianism are considered in detail.

A ternary salt system Rb₂MoO₄-Ce₂(MoO₄)₃-Zr(MoO₄)₂ is studied by powder XRD. Single crystals of 5:1:2 ternary rubidium-cerium-zirconium molybdate Rb₅CeZr(MoO₄)₆ are obtained by solution melt crystallization under spontaneous nucleation conditions. The crystal structure is solved by X-ray crystallography (X8 APEX automated diffractometer, МоK_α radiation, 1274 F(hkl), R = 0.0456). The parameters of a trigonal unit cell are: a = b = 10.7248(2) Å, c = 38.796(1) Å, V = 3864.52(14) ų, Z = 6, Rc space group. The three-dimensional complex framework comprises Мо tetrahedra linked to two independent (Ce,Zr)O₆ octahedra. Two types of rubidium atoms occupy large cavities of the framework.

The crystal structure of the coordination compound Na[RuNOCl₃(H₂O)OH]·2H₂O is reported. The complex is studied by IR and NMR spectroscopy, powder and single crystal X-ray diffraction. Crystallographic data determined for H₇Cl₃NNaO₅Ru is: a = 6.648(2) Å, b = 8.216(7) Å, c = 10.063(3) Å, α = 89.75(6)°, β = 70.96(2)°, γ = 78.76(5)°, V = 967.9(2) ų, P1 space group, Z = 4, d_x = 2.165 g/cm³.

New tridentate 2,6-bis(imino)pyridyl ruthenium(II) complexes, [N₃]Ru(H)(Cl)(2,4,6-(CH₃)₃C₆H₂NH₂) (4) and [N₃]Ru(Cl)₂(2,4,6-(CH₃)₃C₆H₂NH₂) (5) ([N₃] = 2,6-(2,4,6-(CH₃)₃C₆H₂N=CCH₃)₂C₅H₃N) have been synthesized and characterized. The crystal of complex 4, which has been grown in benzene/cyclohexane by evaporation at room temperature, was studied by X-ray diffraction. Complex 4 crystallizes in the monoclinic space group C2/c with cell parameters of a = 42.243(4) Å, b = 8.1480(5) Å, c = 23.662(2) Å, β = 117.998(1)°, V = 7191.1(10) ų, and Z = 8. The molecular structure of 4 shows a six coordinate, pseudo-octahedral geometry with a trans arrangement of hydrogen and chloride ligands. The mesityl ligands are oriented approximately perpendicular to the 2,6-bis(imino)pyridyl ligand plane, and form a pocket surrounding the 2,4,6-trimethyl benzenamine ligand. The coordinated 2,4,6-trimethyl benzenamine (2,4,6-(CH₃)₃C₆H₂NH₂) is in the cis to chloride and hydride, trans to pyridine ligand, and lies parallel to one of the mesityl rings.

A new complex of 2-aminopyridine and malonic acid in a 1:1 stoichiometric ratio is obtained. The complex crystallizes in a centrosymmetric P2₁/c space group with a = 3.8522(2) Å, b = 17.5226(8) Å, c = 13.7317(7) Å and β = 94.418(3)°. This complex is held by network of hydrogen bonds between the protonated 2-aminopyridinium cation and the malonate anion. There is no phase transition observed in this complex, which is verified using DSC and single crystal X-ray measurement studies. Unlike 2-aminopyridinium maleate, this complex crystallizes in the centrosymmetric space group and hence, this complex will not exhibit any non-linear optical property.

An X-ray structural examination is carried out for 2,3-dimethyl-5-(2′-methylprop-1′-enyl)-6-(morpholyl-4′-carbonyl)-cyclohex-3-en-1-carboxlic acid that is one of the products of the Diels-Alder reaction of an acyclic monoterpene alloocimene with maleic and citraconic anhydrides followed by the ring opening of adducts with morpholine to corresponding amides. The crystals are triclinic; a = 10.619(1) Å, b = 12.784(2) Å, c = 14.328(2) Å; α = 65.752(1)°, β = 87.932(1)°, γ = 78.120(1)°; V = 1733.0(3) ų, P-1 space group, Z = 4 (two independent molecules). In both molecules, the anti-conformation of the carboxylic group is observed, the conformation being stabilized by an intramolecular hydrogen bond involving the carboxylic hydrogen atom and ketonic oxygen.

The orientation of dihydropyrimidine derivatives containing podand chains is determined in the model receptor using the CiS algorithm. The orientation of compounds with podand chains is compared with the location of compounds without podand chains in the model receptor. The pharmacophore and antipharmacophore parts of the compounds are analyzed. Amino acid residues responsible for the effective interactions of the compounds with podand chains with the binding site of dihydrofolate reductase (DHFR) are identified using the X-ray diffraction data. The mechanism of the action of tuberculostatic compounds with podand chains in their composition is proposed, which assumes the studied molecules to undergo metabolism by cytochrome P450 isoform 3A4 forming metabolites. The most active are the metabolites without the fragments of podand chains, which interact with DHFR. Therefore, the compounds containing podand chains are prodrugs.

A PBE0/6-311G(3d₅f₇,p) quantum chemical method is used to determine the structural parameters of the molecules of sin- and anti-tricyclo[4.2.0.0^2.5]octane, [2.2.2]propellane, tricyclo[3.3.0.0^2.6]octane, prismanes (CH)_2n (n = 1-7), and dicubane С₁₂Н₈. Bond lengths in anti-tricyclo[4.2.0.0^2.5]octane amount to 1.572 Å. The tetratomic ring in tricyclo[3.3.0.0^2.6]octane is a flattened tetrahedron with internuclear distances of 1.551 Å and 2.037 Å. The symmetry of C₈H₈ sin-tricyclo[4.2.0.0^2.5]octa-3,4,7,8-tetrayl moieties in prismanes and metal organic compounds (C₈H₈RhCl₂RhC₈H₈, C₈H₈RhCl₂RhC₇H₈, and C₈H₈PdCl₂) is higher than the symmetry of a free sin-tricyclo[4.2.0.0^2.5]octane molecule.

A series of N-heterocyclic carbene nickel complexes of the type [Ni(N-heterocylic carbene)(NO)(R)] (R = H, Me, HC=CH₂, and C≡CH) are examined to study the influence of a substituent on the molecular structure and bonding of these complexes. Geometrical and AIM analyses of the interaction between Ni and the carbene fragment reveal that for the metal-carbene bond donation is more important than back-donation. The NICS values suggest that aromaticity in the heterocyclic ring is less than in the free heterocycle.

A method to predict the enthalpies of vaporization of ethers with various structures under normal conditions using a modified Randič method is proposed

The temperature dependence of heat capacity of the polycrystalline sample of cobalt(II) clathrochelate in a range of 6-300 K is studied. Based on the smoothed dependence C_p(Т), the entropy and enthalpy values in a temperature range of 8-300 K and their standard values at 298.15 K are calculated. In the C_p(Т) curve in a range of 50-70 K, a process is recorded whose entropy and enthalpy are 1.2 J·(K·mol^-1) and 68 J·mol^-1 respectively. A comparison of the results with the data of a multitemperature X-ray diffraction study makes it possible to attribute this process to the structural phase transition.

From 3-allyl salicylaldehyde and 4-aminoazobenzene (HL), the Schiff-base complex of copper(II) is synthesized and structurally characterized. The crystallographic unit of a CuL₂ (1) single crystal contains two independent molecules of the complex. Coordination polyhedra of copper atoms are slightly distorted squares; azomethine ligands are in the trans-position. The neighboring molecules of the complex are bonded by intermolecular π stacking interactions

Tris(diisopropylammonium)tetrachloridoferrate(III) dichloride crystallizes in the monoclinic space group P2₁/c (a = 7.6685(2), b = 17.6079(3), c = 23.3217(4) Å, β = 91.396(2)°, V = 3148.1(1) ų, Z = 4, T = 113 K) with three diisopropylammonium cations (dip), one tetrachloridoferrate(III) anion, and two chloride anions in the asymmetric unit. The dip cations and the chloride anions form hydrogen bonded one-dimensional polymers along [010]. The tetrachloridoferrate(III) anion, habituated in between these chains, is not involved in any hydrogen bonding. The structural characterization is supported by infrared and Raman spectroscopic data.

In the interaction of Zn(NO₃)₂·6H₂O and adamantane-1,3,5,7-tetracarboxylic acid (H₄atc) in N,N′-dimethyl formamide (DMF) a three-dimensional coordination polymer with the composition [Zn₂(dmf)(H₂O)(atc)]·0.75DMF·0.5H₂O (1) is produced. Its structure is determined by a single crystal X-ray diffraction study