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The article describes a system for setting and stabilizing the radiation frequency of submersible downhole vibrators. It is assumed that submersible downhole vibrators are used for vibration wave impact on the bottomhole formation zone in wells with a depth of 50 to 300 meters, in which the bottomhole part is structurally designed to be able to convert a comprehensive (pulsating) impact into an oscillating one. In this case downhole vibrators must be subject to additional requirements for the frequency range of the radiation and the accuracy of maintaining the frequency. The speed of rotation and the frequency of the rotary hydraulic vibrator, which is installed in the bottomhole, depends on the fluid flow through the vibrator. In the operation of a submersible vibrator as a hydraulic machine, it must be taken into account that the working fluid from the pump to the vibrator is supplied through a system of oil well tubing, which is a long hydraulic line. The authors of the article compiled a block diagram of the control system, taking into account the transfer functions of the flow controller, a long hydraulic line and the vibrator. The text gives valuable information on the possibility of using flow controllers to ensure setting and stabilization of the radiation frequency of the vibrator.

Asymptotics of Hermite–Pade approximants of the first type for Weil functions of discrete Meixner measure and its derivative is studied. We describe a piecewise-analytic curve in the complex plane which attracts part of the zeros of the Meixner multiple orthogonal polynomials. This curve possesses a symmetry property in the equilibrium problem with an external field for logarithmic potential of vector measures with a constraint. Some connection between the considered Hermite–Pade approximants and the theory of Diophantine approximations is presented.

The Newton interpretation of the psi function by rational functions with free poles is studied. A discrete formula for the Rodrigues determinants is obtained and the limit distribution of their zeros is found. The corresponding equilibrium problem of the theory of logarithmic potential is obtained.

A scheme is proposed for the third stage of laser cooling of thulium atoms at a wavelength of 506.2 nm, and a system for stabilising the laser radiation frequency is described, which provides the required characteristics. The transition at a wavelength of 506.2 nm is detected in a magneto-optical trap with the employment of the developed laser setup. The value of hyperfine splitting of the transition upper level is measured, and the single-dimension cooling at this wavelength is observed for the first time.

Изучается ньютоновская интерполяция пси-функции рациональными функциями со свободными полюсами. Получена дискретная формула Родрига для знаменателей. Найдено предельное распределение их нулей. Получена соответствующая задача равновесия теории логарифмического потенциала. Библиография: 11 названий.

Hermite-Padé approximants of the second kind to the Weyl function and its derivatives are investigated. The Weyl function is constructed from the orthogonal Meixner polynomials. The limiting distribution of the zeros of the common denominators of these approximants, which are multiple orthogonal polynomials for a discrete measure, is found. It is proved that the limit measure is the unique solution of the equilibrium problem in the theory of the logarithmic potential with an Angelesco matrix. The effect of pushing some zeros off the real axis to some curve in the complex plane is discovered. An explicit form of the limit measure in terms of algebraic functions is given. Bibliography: 10 titles.

Изучаются аппроксимации Эрмита-Паде второго типа для функции Вейля, соответствующей ортогональным многочленам Мейкснера, и ее производной. Найдено предельное распределение нулей общих знаменателей этих аппроксимаций - многочленов совместной ортогональности с дискретной мерой. Доказано, что предельная мера является единственным решением задачи равновесия с матрицей Анжелеско теории логарифмического потенциала. Обнаружен эффект выталкивания части нулей с вещественной оси на некоторую кривую в комплексной плоскости. Получен явный вид предельной меры в терминах алгебраических функций. Библиография: 10 названий.

A population transfer from the upper level of the clock transition in thulium atoms to the ground level is demonstrated by using radiation with a wavelength of 402 nm. The method for detecting the clock transition excitation that is not affected by technical fluctuations of the number of atoms in an optical lattice is investigated. The hyperfine splitting of the |4f12(3F2)5d5/2 6s2; J = 7/2〉 level in the thulium atom is measured to be 1480(9) MHz. The suggested method for population transfer can be applied to both the hyperfine components of the clock transition intended for compensating Zeeman effect in a thulium optical clock.

The clock transition at a wavelength of 1.14 μm in thulium atoms in an optical lattice in the Lamb – Dick regime is studied. The capture of thulium atoms makes it possible to suppress completely both the transition broadening due to the first-order Doppler effect and the shift of the transition frequency caused by the recoil effect. The excitation spectra of sideband oscillation frequencies and Rabi oscillations of population between the clock transition levels upon resonance excitation are investigated.

—Articulatory event detectors, i.e., detectors of transitions from one articulatory state to another, are formed on based on analysis of spectral–temporal inhomogeneities in a speech signal. A triad such as /pause–fricative–vowel/ is segmented and recognized in the space of the principal components of the response spectrum of the detector of the pause–fricative transition, the spectrum of the fricative at its peak energy, and the response spectrum of the detector of the fricative–vowel transition at this detector’s peak. The root-mean-square error with respect to manual marking for the onset of fricatives is, on average, about 12 ms, and for the moment of the fricative–vowel transition, about 5 ms. Triad recognition errors with the same fricative and different subsequent vowels, as well as triad recognition errors differing only in the presence or absence of vocal excitement, constituted a few percent.

В статье приводится описание автоколебательного гидравлического привода несимметричного действия и стенда для его экспериментальных исследований, позволяющего определить основные динамические параметры исследуемого привода. В работе представлены характеристики привода при работе под нагрузкой и на холостом ходу.

Optical atomic clocks have already overcome the eighteenth decimal digit of instability and uncertainty, demonstrating incredible control over external perturbations of the clock transition frequency. At the same time, there is an increasing demand for atomic (ionic) transitions and new interrogation and readout protocols providing minimal sensitivity to external fields and possessing practical operational wavelengths. One of the goals is to simplify the clock operation while maintaining the relative uncertainty at a low 10−18 level achieved at the shortest averaging time. This is especially important for transportable and envisioned space-based optical clocks. Here, we demonstrate implementation of a synthetic frequency approach for a thulium optical clock with simultaneous optical interrogation of two clock transitions. Our experiment shows suppression of the quadratic Zeeman shift by at least three orders of magnitude. The effect of the tensor lattice Stark shift in thulium can also be reduced to below 10−18 in fractional frequency units. This makes the thulium optical clock almost free from hard-to-control systematic shifts. The “simultaneous” protocol demonstrates very low sensitivity to the cross-talks between individual clock transitions during interrogation and readout., There are continuous efforts in improving the stability and systematic shifts of optical clocks. Here the authors demonstrate thulium optical clock utilizing bicolor scheme involving interrogation of both hyperfine levels and they are able to cancel the quadratic Zeeman shift.

The 1.14 µm inner-shell magnetic dipole transition in neutral thulium possesses very low blackbody radiation shift in comparison to other neutrals. Together with other features of Tm electronic structure it opens new perspectives for compact optical clocks almost free from hard-to-control systematic shifts.

Differential dynamic polarisability of the inner-shell clock transition at a wavelength of 1.14 μm in the thulium atom is measured by the method of precision laser spectroscopy in the spectral range of 800 – 860 nm. Experimental data approximated by a theoretical model yield the probability of the transition at λ = 809.5 nm: A809.5 = 460(70) s−1. The values of two magic wavelengths are obtained experimentally, namely, λ m1 = 807.727(18) nm and λ m2 = 813.3(2) nm, the wavelength of λ m1 being determined for the first time. Main parameters of an optical lattice at these wavelengths are compared and a conclusion is made that trapping thulium atoms in an optical lattice at λ m2 is preferable for optical clock operation.

Aim. To assess the efficiency and effectiveness of medical institutions (legal entities) that provide primary health care to the population of Stavropol Region, to form the analytical, scientifically based decision-making base for optimizing the primary health care sector of the Stavropol Region. Methods. The comprehensive analysis of the efficiency and effectiveness of the activities of medical institutions providing primary health care based on the developed technique. Results. The results of the study confirmed the objectivity of the developed system of multi-criteria evaluation of the effectiveness and efficiency of the activities of medical institutions providing primary health care to the population. The results of the assessment became an evidence base for improving the activities of medical institutions providing health care in outpatient settings, and allow providing the comparative analysis of their performance, which is integrated into a single indicator, the well-being index, to form the ratings of medical institutions in the region. Conclusion. The results of the assessment will serve as the evidence base for choosing priority socially important directions and will optimize the activity of providing primary health care to each medical institution of the entire system of outpatient primary health care in Stavropol region.

The atomic energy levels corresponding to states with the zero projection of the total angular momentum have a weak sensitivity to certain sources of shifts and, therefore, are widely used in precision spectroscopy. The optical pumping of ultracold thulium atoms to the ground state level with the zero projection of the total angular momentum is described. The population dynamics of this state due to magnetic dipole − dipole interaction in an external magnetic field is studied.

The study objectiveis to perform the acoustic analysis of voice in patients after open diagonal resection of the larynx.Materials and methods. A total of 112 patients underwent diagonal resection of the larynx; of them 73 hadfrontolateral resection and 39 had expanded frontolateral resection. Primary laryngeal cancer was diagnosed in 107 patients; five patients had relapses after radiation therapy. Fifty-six participants underwent acoustic analysis of voice before surgery, 52 participants underwent it 1 month postoperatively, and 112 participants had it after completing their rehabilitation (6 months to 10 years postoperatively). To determine normal acoustic characteristics of voice, we examined 80 men with normal voice. We measured voice fundamental frequency (FF), maximum and minimum FF, FF variability, jitter, shimmer, voice intensity, amplitude of fundamental tone’s harmonics and their difference. Speech rehabilitation included breathing exercises according to E. Ya. Zolotareva and speech training according to S.L. Taptapova.Results.Patients with laryngeal cancer demonstrated significant changes in the acoustic characteristics of their voice (p 0) (up to 143 ± 45 Hz vs 118 ± 18 Hz in controls), decreased voice intensity (from 60 ± 8 to 43 ± 8dB), and almost 2-fold decrease in the amplitude of fundamental tone’s harmonics (ω0, 2 ω0, 3 ω0). We also found an increased dispersion and variability of acoustic characteristics assessed compared to healthy individuals. The analysis of long-term treatment outcomes demonstrated more significant improvement of voice acoustic characteristics in patients who underwent speech rehabilitation compared to those who had no rehabilitation.Conclusion.Open resection of the larynx with endoscopic removal of granulations and ligatures and laser restoration of the laryngeal lumen by dissecting the scars complemented by speech rehabilitation allow restoring respiratory function in 91.1 % of patients and restoring voice in 91.8 % of patients (to achieve acoustic characteristics close to normal).

Introduction. The most urgent tasks of road construction is to improve the sustainability of the roadway, on which the durability of the road surface largely depends and vibration processes are widely used. Moreover, the mechanization of production processes in construction, the growth of power and speed of technological equipment lead to increasing in dynamic loads on its parts and assemblies. To reduce the dynamic loads in the parts and assemblies of construction machines and equipment, as well as to reduce the negative impact of vibration on the staff, it is necessary to isolate the vibration-generating units and assemblies from the base part of the machine.Materials and methods. The vibro-supports of various designs are used to isolate the vibro-active elements of machines. The authors propose the vibration support design with a quasi-zero stiffness effect, in which the rubber-cord shell of the I-09 type is used as a supporting elastic element, and also the toroid-shaped rubber shell that relies on four identical support segments. In addition, each segment represents the fourth part of the annular tube and cut into two parts by a vertical cylindrical plane. The outer parts of each segment are connected with hinges to the posts and fixed on the support base, and the inner parts of each segment are also connected to a supporting elastic element and a vibration-proof mass is connected by means of hinges. The authors describe the working procedure of the proposed construction and compile the mathematical model of vibration support with a quasi-zero stiffness effect.Results. As a result, the equations of the mathematical model are performed in Matlab with the Simulink extension. The values of the equations are used to plot the strain variation of the toroidal shell of the corrector, which depends on the mass displacement, as well as on the motion patterns of a vibrationproof object of 100 kg for variants of the carrier spring without additional volume and with additional volume of the 1 - 10 Hz pneumatic spring carrier.Discussion and conclusions. The authors determine the pressure in the corrector shell, depending on the isolated object mass. Therefore, the deformation of the corrector shell could be provided with a support structure due to the elasticity of the shell material. The usage of additional volume together with the stiffness corrector allows to obtain a wider area of the load characteristics with quasi-zero stiffness and to improve the vibration-protective properties of the support.

On a comprehensive speech database, speaker recognition characteristics are compared under the usage of various voice-source models. Inverse problems to find a source via vowel speech segments are solved on the base of a special speech-production model and voice-source models (A-source, piecewise-linear source, nonparametric source, and source found by means of the spectral relation method). In the first stage, we find the pulses such that the relative residuals of their segmented and their theoretical analogs computed by means of the speech-production model are less than 0.25. For the selected pulses, a posteriori estimates of the error of their determining are computed and the final selection of the source pulses is performed: for the recognition procedure, we leave only pulses with a posteriori estimates of the error less than the accepted level 0.3. In the space of parameters found for each source model, a statistical model is created for each speaker and the recognition is performed. For the speaker recognition with respect to one vowel, the mean error is approximately equal to 66% for the piecewise-linear source, 61% for the spectral relation method, and 33% for the A-source.

We eliminate the largest systematic shift in thulium optical clock — the second-order Zeeman shift — using average frequency of two clock transitions. This reduces the total systematic shift down to mHz level.

Because of the low sensitivity of a thulium optical clock to black-body radiation and good accuracy and stability estimations, it is considered as a promising transportable optical clock. One of the leading systematic effects for Tm clock transition, i.e., the second-order Zeeman effect, can be canceled by probing two clock transitions between different hyperfine levels of ground and metastable states during clock operation. Herein, we demonstrate efficient optical pumping into the ${m}_{F}=0$ state of both ground hyperfine levels using single-frequency radiation at 418.8 nm. We prepared the atoms in both target states simultaneously and excited two clock transitions alternately. The resulting population of ${m}_{F}=0$ states of ground hyperfine levels was 36% and 3.8% of the initial number of atoms with less than 4% and 0.4% on nonzero magnetic sublevels, respectively. We performed numerical simulations of the optical pumping process, which is able to explain experimental results well.

The vocal source and the pulse shape of the glottal flow are determined through the regularized ratio of the speech signal spectra at the intervals of the open and closed vocal slit within each period of the fundamental tone. Three databases were used: Russian numerals for 216 men and 177 women, the base obtained by converting the Russian database by the codec on 9.2 kbps, and the TIMIT database. The pitch period and 7 coefficients for the principal components of the glottal flow provide an average error of recognizing males below 8% for a sequence of 6 vowels. The minimum average recognition error for the initial base of Russian numerals for females makes about 15%, for males in the codec database makes about 15%, and for males in the TIMIT makes about 44%. The minimum average error of males’ recognition in the space of 7 coefficients for the principal components in the Russian database makes about 26%, but about 27% of the speakers have an average error of less than 10%.

The paper considers the inverse problem of finding the shape of a voice-source pulse from a specified segment of a speech signal using a special mathematical model that relates these quantities. A variational method for solving the formulated inverse problem for two new parametric classes of sources is proposed: a piecewise-linear source and an A-source. The error in the obtained approximate solutions of the inverse problem is considered, and a technique to numerically estimate this error is proposed, which is based on the theory of a posteriori estimates of the accuracy in solving ill-posed problems. A computer study of the adequacy of the proposed models of sources, and a study of the a posteriori estimates of the accuracy in solving inverse problems for such sources were performed using various types of voice signals. Numerical experiments for speech signals showed satisfactory properties of such a posteriori estimates, which represent the upper bounds of possible errors in solving the inverse problem. The estimate of the most probable error in determining the source-pulse shapes for the investigated speech material is on average ~7%. It is noted that the a posteriori accuracy estimates can be used as a criterion for the quality of determining the voice-source pulse shape in the speaker-identification problem.

Multiple orthogonal polynomials for three discrete Meixner measures with identical exponential decay at infinity are studied. These polynomials are the denominators of the type II Hermite–Pade approximants to some hypergeometric functions. The limit distribution of zeros of such polynomials scaled in a certain way is described in terms of equilibrium logarithmic potentials and in terms of algebraic curves.

The asymptotic behavior of the Hermite–Pade approximants of the first type for two beta functions are studied. The results are expressed in terms of equilibrium problems of logarithmic potential theory and in terms of meromorphic functions on Riemann surfaces.

The inverse problem with respect to functions proportional to a voice source and volume velocity of the air flow through the glottis is solved as follows: we compute the inverse Fourier transform of the regularized fraction of short-term speech-signal spectra at intervals with an opened (closed) glottis, minimizing the optimality criterion with respect to the regularization parameter and the glottis opening (closing) time. The optimality criterion for solutions includes the values of the volume velocity and its time derivative at the ends of the interval with an opened glottis and the total value of the negative volume velocity. To obtain an empirical error estimate for the solution, experiments using synthesized signals with various parameters, direct measurements of the glottis, and signals synchronously recorded through pairs of microphones of different types are performed. The most probable determination error for the volume velocity is less than 5% for synthetic sources; if the area of the glottis of the source is measured experimentally, then the said error is about 10%. The discrepancy of solutions for the same signal synchronously recorded through a pair of microphones of different types is less than 10%.

The article describes the developed asymmetric self-oscillating hydraulic drive and a stand for determining its dynamic characteristics. The design feature of the self-oscillating drive is that the switching of the working fluid in the cylinder cavity is made by two spools mounted inside the piston, while the working fluid is supplied to the spools by the hollow rod. The test stand is based on the principle of throttling the working fluid when it flows from one cavity of the loaded hydraulic cylinder to another. Stand tests of the developed drive have shown its reliability at different values of the piston stroke and at different operating pressures. The paper presents the characteristics of the drive when operating under load and at idle..

The problem of speaker recognition from a given set of speakers for any language and any context is considered. A database of Russian numerals that contains speech segments from 216 men and 177 women, each of whom spoke from 400 to 800 words, is used for recognition. Speech has been recorded on different types of microphones in different rooms at the natural noise level. Recognition is based on solutions of the inverse problem of finding the voice excitation pulse shape for each pitch period by the known speech segment. The pulse shape is defined as the inverse Fourier transform of the regularized ratio of speech signal spectra at the intervals of the open and closed glottis. Recognition is carried out by ten parameters: the pitch period, the open glottis interval duration, times when the source amplitude is maximum, minimum, or zero, the amplitude ratio for the minimum and maximum source pulses, three decomposition ratios of the source function by the principal component method, and the vowel duration. In such a recognition procedure, in the case of the utterance of a word that contains one vowel, the false reject rate (FRR) for men is 1.7---5.4%, and the false acceptance rate (FAR) is 5.4---7.1%. For women FRR = 2---5.2% and FAR = 5.2---6.3%. The recognition error decreases with an increasing number of vowels in the speech signal. At 10 vowels, for men FRR = 0.05---0.2% and FAR = 0.07---0.8%, and for women FRR = 0.09---0.2% and FAR = 0.17---2.1%.

The extrema of the logarithmic derivative of the mean energy of a voice signal in the frequency range of 1000–3000 Hz are used to determine the instants of opening and closure of the glottis. The inaccuracy of analysis is estimated with the Arctic CMU database, which contains synchronous recordings of speech signals and electro-glottograms. The estimates of the instants of opening and closure of the glottis, found by the developed algorithm, are compared with the instants of the maximum and minimum of the derivative from electro-glottogram signals, which are taken as the “true” instants. The mean square deviation of the glottal opening instant from the extrema of the derivative from the electro-glottogram signals for different speakers is in the range of 1.03–1.64 ms. The error rate of a false estimate of the glottal opening instant is from 0.01 to 0.14%, and the error rate of omission is from 0.42 to 2.38%. An error-detection algorithm is developed. The mean square deviation with an relative—to the period of the fundamental tone—error in detecting the glottal opening instant is in the range of 13–18% for the most probable error from 0 to +5%.

In this paper, we realize growth of the delta doped layer (3 nm thick) with high concentration of nitrogen atoms (about 1.4 × 1019 cm−3) during CVD diamond growth process. We experimentally investigate the distribution of the nitrogen inside the grown layer and formation of the NV centers during such growth. Using confocal microscopy, we analyze the spatial distribution of the NV centers and investigate the formation efficiency of the NV centers in delta doped layers. The spatial distribution is measured by two methods, using second-order correlation function and emission volume analysis, and NV center concentration is found to be 3.9 ± 0.6 and 2.7 ± 0.2 μm-2 consequently. The divergence between the methods is discussed. As-grown NV centers formation efficiency was found to be 30 times lower than in the case of uniform doped diamond growth. Nevertheless, coherence time of an electron spin for a single NV center inside the delta layer was found to be around 1 μs which is quite reasonable given the concentration of the nitrogen in the sample.

Currently, there are no sufficiently effective submersible vibrators for the implementation of a promising technology for vibro-seismic impact on oil and gas reservoirs. In this paper, we consider the possibility of using a downhole elastic wave generator based on a two-stage centrifugal nozzle for the vibro-seismic impact technology (VSIT). The equation of non-stationary fluid flow through the nozzle has the form of a nonlinear Van der Pol differential equation. In this paper, when using the method of studying this equation in the Matlab/Simulink application package, the principal possibility of tincture of a well generator to the dominant frequency of an oil reservoir is shown. The result of the study showed that when using an automatic control system, taking into account the hydraulic flow and pressure transmission line, the elastic wave generator can be controlled by the generation frequency with the accuracy necessary for vibro-seismic action on oil and gas formations.