Modeling of phase volume diffractive gratings, part 1: transmitting sinusoidal uniform gratings

A detailed model of the diffraction of plane and Gaussian beams on plane uniform phase Bragg gratings based on Kogelnik\u27s theory of coupled waves is presented. The model describes transmitting gratings with arbitrary orientation in a plane-parallel plate taking into account spectral width and angular divergence of laser beams along with material dispersion of a photosensitive medium. The model results are compared with experimental data for high- efficiency Bragg gratings in a photothermorefractive (PTR) glass

Behaviour pattern of rock mass haulage energy intensity in deep pits

A significant portion of mineral deposits developed by open-pit mining is opened to the full depth by road transport ramps without the use of combined transport. In most cases, this is dictated by the high rate of a pit deepening and multi-stage development. In this study, the energy intensity of rock mass (RoM) haulage from the working zone of a pit to the surface is considered at several hierarchical levels. Mineframe software was used to study 3D-models of open pits with different slope angles in order to test the method of analytical calculation of a pit volume that allowed ensuring accuracy under a wide range of mining conditions. The findings of the research are as follows: with an increase in the pit bottom diameter, the zone of stabilization of rock mass lifting (haulage) height shifts to greater target depths. An increase in the pit slope angles entails shifting the weighted average height to deeper elevations. By increasing the pit target depth, combined modes of transport become more economical in comparison with dump trucks due to an increase in the total volume of rock mass. Depending on the comparison purpose, it was proposed to use different types of energy intensity. For a broad estimation of the rationality of the pair “scheme of opening – mode of transport” for open pits, the ratio of potential energy intensities of rock mass haulage of a considered option of a pit opening and its basic option without transport berms was used. The ratio of potential energy intensities as a function of a pit depth was determined. The values of total energy intensity of rock mass haulage from a pit to the surface were also established

Coupled-wave analysis of apodized volume gratings

This work presents the use of longitudinal refractive index modulation (apodization) in photosensitive glass for improved sidelobe suppression in volume holographic optical elements. We develop a numerical model for both uniform and apodized volume holograms based on rigorous coupled-wave analysis. We validate the model by comparison with a transmissive 1.55-mum uniform volume grating in photothermorefractive glass. We then apply our numerical model to calculate the spectral response of apodized gratings. The numerical results demonstrate that apodization of the refractive index modulation envelope improves spectral selectivity and reduces first and second-order side-lobe peaks by up to 33 and 65 dB, respectively. We suggest a method for creating apodization in volume holograms with approximately Gaussian spatial refractive index profile

Autoresonance in a Dissipative System

We study the autoresonant solution of Duffing's equation in the presence of dissipation. This solution is proved to be an attracting set. We evaluate the maximal amplitude of the autoresonant solution and the time of transition from autoresonant growth of the amplitude to the mode of fast oscillations. Analytical results are illustrated by numerical simulations.Comment: 22 pages, 3 figure

ADAPTING PORTAL DECOMPRESSION FOR ELEVATION OF EFFICACY OF PORTOSYSTEMIC SHUNTING OPERATIONS IN PORTAL HYPERTENSION

Purpose: to improve the results of portosystemic shunting surgical interventions using of procedures of adapting portal decompression during preoperation period. Materials and Methods: the results of transjugular intrahepatic portosystemic shunt (TIPS procedure) in 113 patients were analyzed. In 60 cases the procedure of adapting portal decompression during a period 3-5 weeks using selective vasoconstrictor octreotide in complex with non-selective beta-blockers.Results: during the follow-up postoperative period in group of patients who were undergone for adapting portal decompression the restitution of clinical and laboratory data was noticed and does not increase occurrence of hepatic insufficiency in comparison with control group.Summary: using of adapting portal decompression in preoperative period before TIPS procedure in patients with complicated portal hypertension is effective for prophylaxis of making worse of hepatic insufficiency

Model of vocational school, high school and manufacture integration in the regional system of professional education

© 2015, Canadian Center of Science and Education. All rights reserved. Integration of vocational, high schools and manufacture contributes to qualified personnel for the regional oil industry effective training. So this article is aimed at the model development of vocational, high school and manufacture integration in the regional system of vocational education. The basic approach to the structural-functional model development of vocational, high school and manufacture integration in the regional system of vocational education is an integrative one, taking into consideration the integrated system “vocational school-high school-manufacture” components in their unity and cooperation, giving it the integrity and structural and functional stability. Structural-functional model of vocational, high school and manufacture integration in the regional system of vocational education includes functional-target, organizational-structural, content, process and result components

Neutron Bang Time Detector Based on a Light Pipe

A neutron bang time detector consisting of a scintillator, light pipe, photomultiplier tube (PMT), and high-bandwidth oscilloscope has been implemented on the 60-beam, 30-kJ OMEGA Laser Facility at the University of Rochester's Laboratory for Laser Energetics. Light from the scintillator, located 23 cm from the target, is transmitted outside the target bay through a 9.6-m-long, 2-in.-diam polished stainless steel pipe to the PMT. The PMT signal is recorded by two channels of a 6-GHz, 10-GS/s Tektronix 6604 oscilloscope. The OMEGA optical fiducial pulse train is recorded on the third oscilloscope channel using a fast photodiode to provide the timing reference to the laser. The bang-time detector is absolutely calibrated in time and is able to measure bang time for neutron yields above 1 x 10{sup 9} with accuracy of better than 25 ps

The A‐dependenc of ψ production in π− nucleus collisions at 530 GeV/c

The E672/E706 Spectrometer, located in the MW beam at Fermilab, was used to collect data on events containing a pair of muons in the final state with large effective mass. The momentum of incident pions and protons was 530 GeV/c. Nuclear targets included Be, C, Al, Cu and Pb. We report on a preliminary measurement of the A‐dependence of the per nucleus cross section for forward J/ψ production. The apparatus also detected charged particles and γ’s produced in association with the muon pair. The expected physics results on the hadroproduction of χ states and beauty particles are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87663/2/624_1.pd

Mechanosynthesis of Pentiptycene-Based Polyesters and Polycarbonates

Received: 14.05.2024. Revised: 07.07.2024. Accepted: 15.07.2024. Available online: 24.07.2024.This work was performed using the equipment of the Joint Use Center "Spectroscopy and Analysis of Organic Compounds" of the I. Ya. Postovsky Institute of Organic Synthesis of the Ural Branch of the Russian Academy of Sciences.Iptycenes are common building blocks for the small-molecules or polymerbased chemosensors and fluorophores. In addition, iptycene derivatives are widely presented in polymers of intrinsic microporosity (PIMs) as materials for the separation and purification technologies. In this manuscript we wish to report a mechanochemical approach to pentiptycene-based polyesters and polycarbonates as, possibly, new representatives of PIMs. Our approach involves the polycondensation reaction between 5,7,12,14-tetrahydro-5,14:7,12- bis([1,2]benzeno)pentacene-6,13-diol (pentiptycene-6,13-diol) and triphosgene or oxalyl chloride under ball-milling conditions. The obtained polymers were characterized by means of 1H NMR- and IR-spectroscopy. As the last step, the fluorescence “turn-off” response of pentiptycene-6,13-diol and two pentiptycene-based polymers towards nitroanalytes (2,4-dinitrotioluene (DNT) and 2,4,6-trinitrophenole (picric acid, PA)) was investigated, and Stern-Volmer constants as high as 1o4 M–1 were observed.The authors are thankful to the Ministry of Science and Higher Education of the Russian Federation (Agreement # 075-15-2022-1118 dated 29.06.2022), http://www.minobr-nauki.gov.ru