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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.

One of the key systematic effects limiting the performance of state-of-the-art optical clocks is the blackbody radiation (BBR) shift. Here, we demonstrate unusually low sensitivity of a 1.14 μm inner-shell clock transition in neutral Tm atoms to BBR. By direct polarizability measurements, we infer a differential polarizability of the clock levels of −0.063(30) atomic units corresponding to a fractional frequency BBR shift of only 2.3(1.1) × 10−18 at room temperature. This amount is several orders of magnitude smaller than that of the best optical clocks using neutral atoms (Sr, Yb, Hg) and is competitive with that of ion optical clocks (Al+, Lu+). Our results allow the development of lanthanide-based optical clocks with a relative uncertainty at the 10−17 level., Precise and stable optical clocks are important for fundamental science and applications. Here the authors demonstrate a clock transitions in thulium (Tm), which has a small black body radiation frequency shift and is suitable for transportable atomic clocks.

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.

Properties of silicon-vacancy (SiV) colour centres in ultra-nanosize diamonds are studied. Nanodiamonds are obtained at a high temperature and pressure, which induced transformations in mixtures of organic and hetero-organic compounds without metal-catalysts. The size distribution of grown nanodiamonds is determined by the methods of transmission electron microscopy and atomic-force microscopy, as well as by using the model of phonon spatial localisation. In addition, Raman spectra of various nanodiamonds and luminescence properties of SiV-centres are investigated.

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.