Vector Area Theorem mapping in crystals and polarization stability of SIT-solitons

The stability of polarization, areas, and number of self-induced transparency (SIT)-solitons at the output from the LaF_3:Pr^{3+} crystal is theoretically studied versus the polarization direction and the area of the input linearly polarized laser pulse. For this purpose the Vector Area Theorem is rederived and two-dimensional Vector Area Theorem map is obtained. The map is governed by the crystal symmetry and takes into account directions of the dipole matrix element vectors of the different site subgroups of optically excited ions. The Vector Area Theorem mapping of the time evolution of the laser pulse allows one to highlight soliton polarization properties.Comment: 3 pages, 3 figures; v2: minor corrected labels in Fig. 3 and its cuptur

Hidrolisis Selulosa dari Pod Husk Kakao Menggunakan Asam Sulfat

The general objective of this study was to determine the effect of the concentration of NaOH in cellulose extraction of cocoa pod husk of the physical properties of cellulose, determine the relationship between was increased concentration of sulfuric acid (H2SO4) with glucose produced from cellulose hydrolysis process cocoa pod husk during hydrolysis and determine the rate of decay glucose levels after the achievement of the optimum point of hydrolysis of the cocoa pod husk. This study was consisted of two steps: (I) The extraction of cocoa pod husk using NaOH concentration of 10%, 12% and 14%, and (II) Hydrolysis of cellulose in various concentrations of H2SO4 ie: 1.0 M; 1.5 M; 2.0 M and 2.5 M. Variable observation in stage I includes yield and brightness were analyzed using a completely randomized design with advanced test Honestly Significant Difference (HSD) 1%. Furthermore, in the second stage is variable levels of glucose in various concentrations of H2SO4 and the glucose damages after the optimum point. The results showed that the concentration of NaOH 12% give the cellulose yield of 29.14% and 46.79% of brightness which is the best result for the production of cellulose as a raw material on step II in this research. Results of step II showed that the highest glucose levels found in H2SO4 concentration of 2.5%, amount to 23.17% at the optimum point of 6.70 hours with the correlation between the time of hydrolysis with the glucose production rate amounted to 77.22% where the damage occurred after the point optimum 7 hours. From the results of this study was concluded that the concentration of NaOH 12% is a better concentration in the extraction of cellulose from cocoa pod husk in particular on the yield and brightness of cellulose. There is a linear relationship between the concentration of sulfuric acid and glucose levels occur on the hour of 6 to 7 on process of hydrolysis of cellulose cocoa pod husk and the rate of the damage of glucose have been increased in line with increasing hydrolysis time after reaching the optimum point. The cocoa pod husk cellulose hydrolysis using H2SO4 should be not more than 7 hours due to the acid catalyst destructive glucose was produced. Necessary to study hydrolysis using other cellulosic feedstocks using an acid catalyst

Current-induced phase transition in ballistic Ni nanocontacts

Local phase transition from ferromagnetic to paramagnetic state in the region of the ballistic Ni nanocontacts (NCs) has been experimentally observed. We found that contact size reduction leads to an increase in the bias voltage at which the local phase transition occurs. Presented theoretical interpretation of this phenomena takes into the account the specificity of the local heating of the ballistic NC and describes the electron's energy relaxation dependences on the applied voltage. The experimental data are in good qualitative and quantitative agreement with the theory proposed.Comment: 8 pages, 2 figure

Ontological status of numbers and the role of mathematics in the methodology of the natural sciences

The aim of the study - to try to determine the ontological status of the number and describe the role of mathematics in the methodology of natural sciences.Цель исследования – попытаться определить онтологический статус числа и описать роль математики в методологии естественных наук

The vertical distribution and biological transport of marine microplastics across the epipelagic and mesopelagic water column.

Plastic waste has been documented in nearly all types of marine environments and has been found in species spanning all levels of marine food webs. Within these marine environments, deep pelagic waters encompass the largest ecosystems on Earth. We lack a comprehensive understanding of the concentrations, cycling, and fate of plastic waste in sub-surface waters, constraining our ability to implement effective, large-scale policy and conservation strategies. We used remotely operated vehicles and engineered purpose-built samplers to collect and examine the distribution of microplastics in the Monterey Bay pelagic ecosystem at water column depths ranging from 5 to 1000 m. Laser Raman spectroscopy was used to identify microplastic particles collected from throughout the deep pelagic water column, with the highest concentrations present at depths between 200 and 600 m. Examination of two abundant particle feeders in this ecosystem, pelagic red crabs (Pleuroncodes planipes) and giant larvaceans (Bathochordaeus stygius), showed that microplastic particles readily flow from the environment into coupled water column and seafloor food webs. Our findings suggest that one of the largest and currently underappreciated reservoirs of marine microplastics may be contained within the water column and animal communities of the deep sea

Ballistic and Diffuse Electron Transport in Nanocontacts of Magnetics

The transition from the ballistic electron transport to the diffuse one is experimentally observed in the study of the magnetic phase transition in Ni nanocontacts with different sizes. It is shown that the voltage $U_C$ needed for Joule heating of the near-contact region to the critical temperature does not depend on the contact size only in the diffuse mode. For the ballistic contact it increases with decrease in the nanocontact size. The reduction of the transport electron mean free path due to heating of NCs may result in change of the electron transport mode from ballistic to diffusive one.Comment: 7 pages, 2 figures accepted for the publication in JETPL (http://www.jetpletters.ac.ru). Will be published on 25 april 201

Low magnetic fields behavior of photon echo in LuLiF4:Er3+

It is reported about the first observation and studying of the photon echo in LuLiF4:Er3+. The energy transition is 4I15/2 → 4F9/ 2 (λ = 6536 Å). The density of ErF3 is 0.025 wt%. The operation temperature is 1.9 K. Measurements were spent at low (up to 1200 Oe) and even zero external magnetic fields. It was studied a behavior of the photon echo intensity versus the magnetic field mgnitude and direction about the crystal axis C and versus the laser pulse separation t12. It was observed an expotential growth and then, after some plateau, an exponential decreasing of the photon echo intensity as a function of magnetic field with increasing of the magnetic field from zero value. The parameters describing the exponential growth and decreasing are not depended on direction of magnetic field. Value of a magnetic field at which the echo intensity accepts the maximum, and quantity of this maximum decrease with increased the pulse sepatation t12 and the angle θ between the magnetic field and crystals axis. The echo intensity expotentially decreases with increased θ. The parameter describing the exponential decreasing is not depended on the magnitude of the field. The echo intensity as a function of pulse separation shows exponential decay. The phase relaxation time is depended on the magnitude and direction of the magnetic field. T2 is equal to 202±16 ns at zero magnetic field. Phenomenological formula is suggested, which qualitatively presents the mentioned dependencies. Polarization properties of the backward photon echo in this crystal are studied also. A graph is presented. Echo size versus magnetic field directed as along optic axis as at an angle of θ = 5° of different values of t12. The color symbols show experimental points. The solid curves were calculated using experession (1). The Y-scale is logarithmic. © 2006 by Astro Ltd. Published exclusively by Wiley-VCH Verlag GmbH & Co. KGaA

УСТАНОВКА СОВМЕЩЕННОГО ПРОЦЕССА НЕПРЕРЫВНОГО ЛИТЬЯ И ДЕФОРМАЦИИ ДЛЯ ПРОИЗВОДСТВА БИМЕТАЛЛИЧЕСКИХ ПОЛОС

The results of studying a new combined process of continuous casting and deformation for manufacturing bimetallic strips are presented. A procedure for calculating parameters of the manufacturing process and installation for the production of bimetallic strips is proposed. Stresses in the deformation region of metal of the cladding layer when producing steel–aluminum bimetal are determined. To evaluate a new manufacturing technology of bimetallic strips and bimetal quality, experimental investigations of fabricating steel–aluminum bimetal using a pilot installation are performed.Приведены результаты исследования нового совмещенного процесса непрерывного литья и деформации для получения биметаллических полос. Предложена методика расчета параметров технологического процесса и установки для производства биметаллических полос. Определены напряжения в очаге деформации металла плакировочного слоя при получении биметалла сталь–алюминий. Для оценки новой технологии и качества биметалла проведены экспериментальные исследования получения на опытной установке биметалла сталь–алюминий

Compton Scattering by the Proton using a Large-Acceptance Arrangement

Compton scattering by the proton has been measured using the tagged-photon facility at MAMI (Mainz) and the large-acceptance arrangement LARA. The new data are interpreted in terms of dispersion theory based on the SAID-SM99K parameterization of photo-meson amplitudes. It is found that two-pion exchange in the t-channel is needed for a description of the data in the second resonance region. The data are well represented if this channel is modeled by a single pole with mass parameter m(sigma)=600 MeV. The asymptotic part of the spin dependent amplitude is found to be well represented by pi-0-exchange in the t-channel. A backward spin-polarizability of gamma(pi)=(-37.1+-0.6(stat+syst)+-3.0(model))x10^{-4}fm^4 has been determined from data of the first resonance region below 455 MeV. This value is in a good agreement with predictions of dispersion relations and chiral pertubation theory. From a subset of data between 280 and 360 MeV the resonance pion-photoproduction amplitudes were evaluated leading to a E2/M1 multipole ratio of the p-to-Delta radiative transition of EMR(340 MeV)=(-1.7+-0.4(stat+syst)+-0.2(model))%. It was found that this number is dependent on the parameterization of photo-meson amplitudes. With the MAID2K parameterization an E2/M1 multipole ratio of EMR(340 MeV)=(-2.0+-0.4(stat+syst)+-0.2(model))% is obtained