Optimisation of micro-structured waveguides in lithium niobate (z-cut)

We present an optimization procedure to improve the propagation properties of the depressed cladding, buried micro-structured waveguides formed in a z-cut lithium niobate (LN) crystal by high repetition rate femtosecond (fs) laser writing. It is shown that the propagation wavelength for which the confinement losses of ordinary (O) and extraordinary ordinary (E) polarizations are below 1 dB/cm can be optimized beyond 3 micro meter for hexagonal WG structures with seven rings of tracks

Investigation of ultrafast laser photonic material interactions: challenges for directly written glass photonics

Currently, direct-write waveguide fabrication is probably the most widely studied application of femtosecond laser micromachining in transparent dielectrics. Devices such as buried waveguides, power splitters, couplers, gratings and optical amplifiers have all been demonstrated. Waveguide properties depend critically on the sample material properties and writing laser characteristics. In this paper we discuss the challenges facing researchers using the femtosecond laser direct-write technique with specific emphasis being placed on the suitability of fused silica and phosphate glass as device hosts for different applications.Comment: 11 pages, 87 references, 11 figures. Article in revie

The use of innovative technologies in a pedagogical university in the implementation of disciplines (modules) in physical culture and sports

The article presents research data related to the interest of teachers in the use of information technologies in the educational process of the university in the discipline (module) of physical culture and sports. The reasons for the introduction of mobile applications into the educational process for reading sports results (number of steps, speed, mileage, etc.) are substantiated and recommendations for teachers of higher educational institutions on improving pedagogical skills when using information technologies are determined

Compliance of the Quality of Educational Services Provided by Vocational Education Institutions With the Labor Market Demand in Qualified Staff Under Economic Crisis

The labor potential in Ukraine functions under the economic crisis and social contradictions in society. At such times, there is a need to develop a mechanism for compliance of the educational services market with the labor market needs, taking into account the balance of supply and demand for labor. The article aims to thoroughly study the compliance of the quality of educational services provided by vocational education institutions (hereinafter - VEIs) to the needs of the regional labor market in qualified staff and professional career development. To conduct the research, the authors used a set of theoretical and empirical methods: theoretical. The authors have tested the analysis system of professional success of vocational education graduates and developed technology for evaluating the effectiveness and quality of educational services provided by VEIs. By the above, the authors offer to organize activities of Advisory Committees and Professional Councils in the field as an innovative interaction form between vocational education institutions and employers in the professional educational environment

Sub-critical regime of femtosecond inscription

We apply well known nonlinear diffraction theory governing focusing of a powerful light beam of arbitrary shape in medium with Kerr nonlinearity to the analysis of femtosecond (fs) laser processing of dielectric in sub-critical (input power less than the critical power of selffocusing) regime. Simple analytical expressions are derived for the input beam power and spatial focusing parameter (numerical aperture) that are required for achieving an inscription threshold. Application of non-Gaussian laser beams for better controlled fs inscription at higher powers is also discussed. © 2007 Optical Society of America

Carcinogenicity Screening of Chemicals Using Positron Annihilation Spectroscopy

Chemical carcinogens are the main cause of cancer. Many thousands of new chemicals are synthesized annually in the world, unknown part of them is carcinogens. There are several methods, which are currently used for testing carcinogenicity. The fastest arephysicochemical methods. We suggest the method of fast carcinogen screening using the positron annihilation spectroscopy (PAS). It is based on the fact that the presence of carcinogens, being strong electrophiles, significantly decreases positronium (Ps) formation probability. This quantity can be measured by means of conventional PAS techniques: positron annihilation lifetime spectroscopy (PALS), angular correlation of annihilation radiation (ACAR) or Doppler broadening of annihilation radiation (DBAR). It is also possible to evaluate anti-carcinogenic properties of chemicals using the anti-inhibition effect of Ps formation. Keywords: carcinogen, electrophilicity, positron annihilation spectroscopy, positroniu

Відповідність якості освітніх послуг, що надаються закладами професійно-технічної освіти, попиту ринку праці кваліфікованих кадрів в умовах економічної кризи

The article aims to thoroughly study the compliance of the quality of educational services provided by vocational education institutions (hereinafter - VEIs) to the needs of the regional labor market in qualified staff and professional career development. The authors have tested the analysis system of professional success of vocational education graduates and developed technology for evaluating the effectiveness and quality of educational services provided by VEIs. By the above, the authors offer to organize activities of Advisory Committees and Professional Councils in the field as an innovative interaction form between vocational education institutions and employers in the professional educational environment.Метою статті є ретельне вивчення відповідності якості освітніх послуг, що надаються закладами професійно-технічної освіти (далі – ЗПТО), потребам регіонального попиту ринку праці щодо кваліфікованого персоналу та професійного кар'єрного зростання. Автори протестували систему аналізу професійних успіхів випускників професійно-технічної освіти та розробили технологію оцінки ефективності та якості освітніх послуг, що надаються ЗПТО. До того ж, автори пропонують організувати діяльність Консультативних комітетів та професійних рад у цій сфері як інноваційну форму взаємодії між закладами професійно-технічної освіти та роботодавцями у професійному освітньому середовищі

Point-by-point inscription of 250-nm-period structure in bulk fused silica by tightly-focused femtosecond UV pulses: experiment and numerical modeling

By conducting point-by-point inscription in a continuously moving slab of a pure fused silica at the optimal depth (170 μm depth below the surface), we have fabricated a 250-nm-period nanostructure with 30 nJ, 300 fs, 1 kHz pulses from frequency-tripled Ti:sapphire laser. This is the smallest value for the inscribed period yet reported, and has been achieved with radical improvement in the quality of the inscribed nanostructures in comparison with previous reports. The performed numerical modeling confirms the obtained experimental results

Exceptional Askey-Wilson type polynomials through Darboux-Crum transformations

An alternative derivation is presented of the infinitely many exceptional Wilson and Askey-Wilson polynomials, which were introduced by the present authors in 2009. Darboux-Crum transformations intertwining the discrete quantum mechanical systems of the original and the exceptional polynomials play an important role. Infinitely many continuous Hahn polynomials are derived in the same manner. The present method provides a simple proof of the shape invariance of these systems as in the corresponding cases of the exceptional Laguerre and Jacobi polynomials.Comment: 24 pages. Comments and references added. To appear in J.Phys.

Estimated Inpatient Hospital Stay in Individual Wards: Guidelines on Radiation Safety after Radioiodine Therapy

Radionuclide therapy safety requirements are regulated by the Russian Radiation Safety Standards (RRSS), which state the maximum allowed radionuclide activity in the body and the equivalent dose rate (EDR) of gamma radiation. Therefore, it is necessary to estimate the time of an inpatient hospital stay in specially designed radionuclide therapy wards. The article presents the findings of individual 131I biokinetics studies in 64 patients admitted to radioiodine therapy of thyrotoxicosis and differentiated thyroid cancer. We developed a method to calculate the time interval to reach the EDR of 20μSv/h and the recommended EDR of 3 and 0.3μSv/h for adults and children, respectively. It is based on the measurement of the 131I excretion constant. Keywords: Radioiodine therapy, Radiation safety, Guidelin