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The state of a soliton is characterized by the eigenvalues of the Zakharov–Shabat problem. The data transfer rate in the fiber-optic communication lines that use eigenvalues for coding signals can be significantly increased only by developing optical eigenvalue control methods. We propose to use optical fibers with a sinusoidally changing dispersion to generate given sets of complex eigenvalues and to detect soliton states. Under the action of a periodic change in dispersion, multisoliton pulses divide into several solitons moving at different group velocities. This effect can be used to prepare fixed sets of eigenvalues. A soliton signal can be recognized by analyzing pulses and their spectra at the exit from a fiber with a periodically changing dispersion. Using the solitons specified by sets of four eigenvalues, we show that the field at the exit from a fiber corresponds to a unique combination of the spectrum and the number of pulses determined by initial eigenvalues.

The spectral parameters of solitons result from the nonlinear Fourier transform for a pulse propagating in a fiber. A new approach for controlling the discrete component of spectral parameters is proposed. In the presence of a resonance between field oscillations and fiber dispersion, the real part of spectral parameters change, which leads to multisoliton pulse separation into fundamental solitons. It is proposed to use this effect for signal decoding in communication lines operating based on the nonlinear Fourier transform.

The relationship between the fixation of organic matter into a form resistant to oxidative destruction and the actual structure of the clay component was studied in profiles of different-aged chernozemic soils of a filled fortification in the Volga Bulgaria. With the use of modern methods (X-ray phase analysis, laser diffraction granulometry, hyphenated thermal analysis-FT-IR spectroscopy, adsorption-luminescence analysis, and ICP emission spectroscopy), it was shown that the formation of organic-smectite complexes with a disordered c*-axis structure is a universal and usual way for the kinetic stabilization of the system during pedogenesis under forest-steppe conditions. The main aim of the study was to experimentally substantiate this phenomenon.

Refraction of light at an interface between a homogeneous dielectric and a two-dimensional photonic crystal is studied. Using the isofrequency method, various cases of refraction, including a change in the magnitude and direction of the wave vector of the incident wave, in the refractive indices of the media, and in the mutual orientation of the interface and the translation vectors of the photonic crystal, are investigated. Different types of refraction and the possibilities for realizing negative and multiwave refraction are considered.

Periodic arrays of air holes with diameters ranging from about 80 nm up to 400 nm are shown to modify intensity profiles of guided modes in photonic-crystal fibers, suggesting new ways of fiber dispersion engineering and modal birefringence control. Guided modes supported by such fibers provide a high efficiency of anti-Stokes frequency conversion for 100-fs pulses of a Cr: forsterite laser.

Numerical modeling methods were used in an investigation of the condition for active mode locking in gas lasers with inhomogeneous broadening of the gain profile. It is shown that a change in the loss modulation frequency gives rise to chaotic and regular instabilities of the output radiation. The characteristics of the resultant chaotic spontaneous oscillations are determined. Equations describing the dynamic model of a laser are derived allowing for trapping of resonant radiation from the upper active level.

A dynamic model is proposed for describing active mode locking in gas lasers with inhomogeneous broadening. Different dynamic regimes are investigated depending on the depth of modulation of the losses. It is shown that disruption of the mode locking regime is accompanied by the appearance of more complex dynamic states, both regular and random, the shape of each individual field pulse having a complex multihump structure which is a consequence of the coherent nature of the interaction of the electromagnetic field with the active medium.

A device is developed to locate both metallic and non-metallic (e.g., explosives, etc.) objects hidden under people's clothes. The device is based on receiving the radiothermal radiation from the surface of the person's body.

At present spaceborne synthetic aperture radar (SARs) operate in the microwave (centimetre and decimetre) band. When used for remote sensing of the Earth's surface, they provide valuable data. However, these SARs appear to be ineffective if it is required to view natural formations and other objects located below and/or under the surface layer. This data are necessary to solve various economical, commercial and ecological problems. The authors show that in principle it is possible to overcome the resolution limitations in transionospheric VHF SARs by means of adaptive processing of received signals at the SAR output. They consider respective algorithms for adaptive compensation for the distortions and their simulation with the use of complex data from an airborne VHF SAR and records of actual phase fluctuations of a VHF signal passing through the ionosphere.

The authors estimated the influence of proton-beam stereotaxic therapy on a course of epileptic fits in cerebral arteriovenous aneurysms (AVA). A stable disappearance of epileptic fits was noted in 16 of 29 patients (56%), in 12 of them (41%) positive angiography results were noted. The calculated D and V fields of irradiation for 16 patients without fits and for 13 patients with epileptic fits after proton-beam stereotaxic therapy have shown that with D being the same, the effect depends upon a fraction of an AVA irradiated area.

A model of the dynamics of a single-longitudinal-mode unidirectional ring laser with a homogeneously broadened medium is proposed. The model includes the transverse variation of the field and of the material parameters and is based on a treatment of the round-trip propagation of a beam in a nonlinear medium rather than on an expansion in terms of the empty-cavity modes. In particular, the case of adiabatically eliminated polarization and inversion is studied. A three-dimensional point mapping is obtained and analyzed. It is shown that this model describes stationary regimes with mode deformation and spatiotemporal (quasi-periodic or periodic) oscillations of both the beam parameters (beam radius and phase-front curvature) and the intensity on the axis.

It is proposed that a feedback resulting from scattering be used to achieve lasing in a disperse reactive medium. The example of a simple two-level system shows that under advanced lasing conditions the quantum efficiency of the radiation emission approaches the quantum efficiency of the excitation of the upper level, and the emission spectrum becomes much narrower. Feasibility of chemical pumping of such a laser is estimated on the basis of calculations of heterophase burning of a drop of a fuel in an oxidizing atmosphere. The growth increment of light is calculated and the threshold conditions for the excitation of lasing are found. Examples are given to illustrate the feasibility of purely chemical pumping of a laser with a nonresonant feedback. It is shown that dense reactive media can be used in such lasers.

Theoretical and experimental investigations were made of the influence of external modulation of the parameters on the characteristics of a ring gas laser with circular polarization of the radiation, operating in a single-mode regime well above the threshold. A report is given of the main results obtained on modulation of the gain, tuning, and magnitude of the frequency pedestal created by the application of an axial magnetic field to the active medium. A good qualitative agreement (and in the case of the static characteristics also a quantitative agreement) is obtained between the experimental results and theoretical calculations based on a large-signal theory. These results can be employed in simulation of technical fluctuations of the parameters of ring lasers with circular polarization of the output radiation caused by vibrations of the resonator, plasma fluctuations, etc.

Coloring methods in graph theory are used in estimating the number of parameters to be determined in a kinetic model corresponding to a linear mechanism. The estimates are based on determining the numbers of differently colored frameworks. Examples are discussed of isomerization and an enzymatic reaction catalyzed by ammonoacyl-MRNA synthetase.

1. Omnilateral pressure, which reduces the martensitic point, does not alter the “explosive” character of the martensite transformation in type N31 Fe−Ni alloy. Omnilateral pressure greatly reduces the transformation rate for an isothermal martensite transformation (type N23G3 alloy) and causes a reduction in the temperature of the kinetic maximum. 2. Preliminary plastic deformation does not reduce the transformation temperature range for N31 alloy but causes a large decrease in the extent of the first and subsequent explosions. Preliminary plastic deformation of Fe−Ni−Mn alloys, which suppresses the isothermal transformation, causes almost no reduction in the extent of the athermal transformation in a magnetic field. Tempering of the austenite inhibits the isothermal transformation but has no effect on the athermal transformation excited by pulsed fields.

Sufficient conditions are obtained for the equality of the chromatic class of a graph to its maximal degree. These conditions are in terms of properties of the graph related to the possibility of its being located on a surface with certain topological properties.

Application of graph-theoretical methods to solving some problems of kinetics of complex reactions is considered. The possibility of reducing the graph-theoretical problems to the multivariate polynomial operations and use of a symbolic manipulation system is shown. The implemented symbolic manipulation system for solving the problems of kinetics of complex reactions is described and example of its usage given.

It is shown theoretically that injection of an optically dense jet between two parallel planar streams establishes a dielectric gas waveguide which localizes light in a narrow reaction zone. It then becomes possible to use narrow inversion zones (with a thickness of the order of 10−2 cm) in cw chemical lasers without suffering the diffraction losses of light. This waveguide effect should make it possible to use gas streams at pressures 1 atm in chemical lasers. A fast chemical reaction, Ba+S2Cl2→S*2(B)+BaCl2, resulting in the emission of visible light is considered by way of example.

Structural parameters of muscles in some diseases have been studied using X-ray diffraction methods. Fixed parts of muscles dissected in the operation correcting the vertebrate shape were used as samples in the case of patients III-IV stage of scoliosis muscles. The sarcomere protofibrillar lattice in muscles was found to be retained until the destruction of the muscle tissue; no differences between the muscles from the convex and concave sides of the vertebrate were observed. This seems to be an evidence of functional inertia of the diseased muscles and of their atrophy. Fixed parts of myocardial muscles taken during surgical correction were used as samples in investigating the Tetralogy of Fallot heart disease in children. A disturbance of packing parameters of the protofibrillar apparatus was observed in a significant part of the apparatus volume. In the case of critical experimental heart deficiency in dogs the protofibrillar lattice structure was retained, probably due to its resistance nature.

The brain was examined (on the basis of neurological and electroencephalographic findings) in 43 patients with hypophysis adenomas both before and at various intervals after a single exposure of the tumour to protons with an energy of 1,000 MeV. The irradiation was performed by the stereotaxic convergent method. The radiation dose absorbed by the tumour was 100 Gy. The local character of the proton action, absence of irreversible changes in the brain, temporary, transient changes on the part of the oculomotor nerves (25.5%) and temporal lobes (9.3%) are demonstrated. The objective remission of the disease was attained in 97.7% of the cases.

A pattern model of a device for tranquilization a relaxation--a photo-acoustic relaxator--was constructed and procedures for its application elaborated. Unlike psychotherapy, hypnosis, autogenic training and pharmacological agents in this method natural factors of actions, such as light and sound are used. The relaxation achieved by rhythmic photoacoustic effects with the help of the device pre-supposes the regulation of the patient's respiration. The effect produced by the relaxation sittings is shown to depend on the temperament of the examined. The use of the device is particularly effective in persons displaying a high degree of suggestibility and emotional susceptibility.

Stereotaxic proton beam therapy using narrow beams (5-10 mm at 50% of isodose) at the energy of 100 MeV in single irradiation and the delivery of absorbed doses, the maximum dosage being 40-80 Gy, was provided to 99 patients with arteriovenous brain aneurysms. An analysis of the therapeutic results based on angiography data was performed in 50 patients with arteriovenous malformations with the volume up to 10 cm3. A positive effect was obtained in 31 of 50 patients.

The activity of the alpha 1-antitrypsin and alpha 2-macroglobulin were studied in 16 breast cancer patients and 25 hypophyseal adenoma patients prior to and at varying time after proton "hypophysectomy". A high alpha 1-antitrypsin level and a normal alpha 2-macroglobulin level were found in all the breast cancer patients. An increase in both blood serum inhibitors was detected in hypophyseal adenoma. The dependence of the alpha 1-antitrypsin content on a subclinical stage of generalized metastatic spread was revealed in the course of 2 years following "hypophysectomy" in the patients with disseminated breast cancer. In the hypophyseal adenoma patients the activity of both inhibitors returned to normal 1 year after treatment and remained within normal during 3 years of follow-up. It was regarded as a positive therapeutic effect. The above findings make it possible to propose the determination of the activity af alpha 1-antitrypsin in breast cancer and alpha 1-antitrypsin and alpha 2-macroglobulin in hypophyseal adenoma as an additional test for the evaluation of the results of proton "hypophysectomy".

The paper discusses the results of a study on the blood-serum levels of alpha 1-antitrypsin and alpha 2-macroglobulin in 29 patients with an extensive breast cancer before and within 3 years after a combination therapy including proton "hypophysectomy". A correlation was established between the blood level of alpha 1--antitrypsin and the subclinical stage of generalized metastatic spreading. Consequently, the assay of the level of this inhibitor is suggested as another test for assessment of the efficacy of treatment of such patients and prediction of the results.

The paper is concerned with analysis of angiographic findings on 62 patients with arteriovenous aneurysms (AVA) of the cerebral vessels who received proton beam stereotactic therapy in the period of 1978-1986 depending on an absorbed dose value of an irradiated volume. Proton stereotactic therapy (PST) of brain AVA located deep in the functionally important regions, can be used as an independent radical therapeutic method in such cases including inoperable ones. Complete AVA elimination from the blood flow or considerable reduction of the AVA volume was achieved in 68% of the patients after delivering a dose of approximately 40 Gy, the AVA volume being approximately 30%. Significant (p less than 0.05) correlation of PST results, a dose of irradiation and a value of the AVA irradiated volume was established in the groups with positive results and in the nonresponding groups.

Theory of population inversion, light gain and laser action is presented for the case of combustion of finely dispersed metal particles sprayed in the gaseous oxidiser. A variety of pairs metal-oxidizer is shown to be applicable as active media for IR and visible lasers.© (1989) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In the period of 1975-1986, 457 patients (81 with breast and prostatic cancer, 24 with endocrine ophthalmopathy, 20 with diabetic angioretinopathy, 206 with pituitary adenomas, 115 with arteriovenous and 6 with arterial brain malformations, and 6 with epilepsy) were given proton beam therapy at the Central Research Roentgenoradiology Institute using the 1000 MeV synchrocyclotron of the Leningrad Institute for Nuclear Physics. A prolonged remission was noted in 75-90% of the patients with pituitary adenomas. Angiography showed complete exclusion of aneurysm from the blood flow 2 yrs. after irradiation almost in 50% of the patients with arteriovenous malformations. A high efficacy and safety of the method was shown.

A theoretical analysis is presented of the conditions necessitating the occurence of the partial population inversion on electronic states of diatoraics as a result of the electronic energy transfer from N(A3∑u+). It is shown that the light gain can exceed 10-4 cm-1 in highly diluted gas mixtures under atmospheric pressure at the N2(A) concentration close to 1014 molecules cm-3.