Methods for controlling of the laser-induced absorption in a BTO crystal by using of cw-laser radiation

A photorefractive BTO crystal is exposed with cw-laser beams (430 mW/cm2 at 514 nm), and the photoinduced absorption between 480 and 900 nm is studied. A method of controlling this absorption by low intensity laser radiation of “green” and “red” wavelengths is demonstrated. The physical mechanism can be explained by the redistribution of electrons on the long-lived energy levels into the forbidden band. Dynamical characteristics of the redistribution are estimated

Numerical method for 2d soliton solution at SHG in media with time‐dependent combined nonlinearity

The paper describes the iteration method for finding the eigenfunctions and eigenvalues of the system of two nonlinear Schrödinger equations, which describes the process of second harmonic generation by femtosecond pulse in media with the quadratic and cubic nonlinear response. Coefficients, which characterize the nonlinearities, depend on one of the coordinate. The discussed method allows to find soliton solutions of new form corresponding to the first and second eigenvalues for the wide range of the nonlinear coefficients values. For determination of the eigenfunctions of the third and higher order it is necessary to select the initial approximation in a special way. First Published Online: 14 Oct 201

Formation of self-trapping waveguides in bulk PMMA media doped with Phenanthrenequinone

Experimental and theoretical investigations of light self-trapping waveguides in a bulk polymeric medium based on polymethylmethacrylate (PMMA) with photosensitive phenanthrenequinone (PQ)-molecules are examined. Self-channeling was generated for the first time in this nonlinear bulk PQ-PMMA media with a thickness up to several millimeters and 0.1 mol. % PQ-concentration. The experimental formation of volume waveguide structures with a length of 2 - 3 cm at different laser wavelengths (405 nm, 488 nm, and 514.5 nm) was demonstrated. The calculations based on a model for the laser beam propagation in the bulk PQ-PMMA medium with competitive nonlinearities are in a good agreement with the experiments

Phase hologram formation in highly concentrated phenanthrenequinone–PMMA media

For phase holographic gratings in layers of polymethylmethacrylate, containing phenanthrenequinone in high concentration (nearly 3 mol%), a discrepancy between experimental (up to 9) and estimated (∼45) magnitudes of the thermal diffusion amplification coefficient has been revealed. Analysis of plausible reasons of the lower experimental efficiency of the diffusion amplification has been carried out. The influence of material deformations on the reflection grating formation process was investigated experimentally. It is shown that thermoactivated amplification of holograms under high phenanthrenequinone concentration and its profound modulation are depressed by the arising density ‘grating’

Holographic volume gratings in a glass-like polymer material

We demonstrate a possibility to write efficient and thermally stable volume holographic gratings in a glassy polymer material based on PMMA and phenanthrenequinone with layers prepared, by casting the liquid solution of ingredients on a substrate and drying to a solid state. A high concentration of phenanthrenequinone (up to 4mol.%) makes it possible to use photosensitive layers of lower thicknesses (50–180 μm) for the recording of efficient holographic gratings. The exposing is followed by a thermal amplification of the grating due to diffusion of residual phenanthrenequinone molecules and fixation by an incoherent optical illumination. We present experimental temporal curves of the refractive index modulation and diffraction efficiency both under the exposure and the heating process. The behavior of the gratings under temperatures up to 140 ◦C has been studied

How unique is the Asymptotic Normalisation Coefficient (ANC) method?

The asymptotic normalisation coefficients (ANC) for the vertex $^{10}$B $\to$ $^9$Be + p is deduced from a set of different proton transfer reactions at different energies. This set should ensure the peripheral character of the reaction and availability of data for the elastic channels. The problems associated with the characteristics of the data and the analysis are discussed. For a subgroup of the set of available data, the uniqueness property of the extracted ANC is fulfilled. However, more measurements are needed before a definite conclusion can be drawn.Comment: 19 pages, 11 figures, to be published in Phys Rev

Температурные графики нагрева эвтектоидных сталей

Problems pertaining to power- and resource-saving while heating eutectoid steel in furnaces of mechanical engineering, automotive and tractor plants (blanking and mechanical assembly production) are considered in the paper. The paper shows that a heating device according to its heating technical parameters must be developed with due account of a temperature diagram having properties which are peculiar to the heated charge.Рассмотрены вопросы, касающиеся энерго- и ресурсосбережения при нагревании эвтектоидных сталей в печах машиностроительных и автотракторных заводов (заготовительное и механосборочное производства). Показано, что нагревательное устройство по своим теплотехнологическим характеристикам должно разрабатываться в соответствии с температурным графиком, обладающим свойствами, присущими нагреваемой садке

Long-term outcomes of combined coronary bypass surgery and carotid endarterectomy in patients with type 2 diabetes

At present, there are no studies on the analysis of the incidence of complications in patients with concomitant lesions of the coronary and internal carotid arteries (ICA) after combined operation of carotid endarterectomy (CE) and coronary artery bypass grafting (CABG) against the background of type 2 diabetes (T2D). However, there is no doubt that this condition can be a predictor of cardiovascular and wound complications during in-hospital and long-term postoperative periods.Aim. To study in-hospital and long-term outcomes of combined CABG+CE in patients with and without type 2 diabetes.Material and methods. This multicenter retrospective study for the period from January 2015 to December 2019 included 653 patients with concomitant atherosclerotic lesions of ICA and coronary arteries, who underwent combined CE+CABG. Depending on presence of type 2 diabetes, 2 groups were formed: group 1 (n=183) — patients with type 2 diabetes; group 2 (n=471) — patients without type 2 diabetes. The duration of postoperative follow-up was 37,8±14,9 months.Results. During hospitalization, significant differences in the incidence of death (group 1 =1,1%; group 2 =1,0%; p=0,97), myocardial infarction (MI) (group 1 =1,1%; group 2 =0,8%; p=0,76), bleeding events (group 1 =1,1%; group 2 =0,8%; p=0,76) were not detected. However, stroke (group 1 =3,8%; group 2 =0,4%; p=0,0008), sternal wound infection and mediastinitis (group 1 =3,3%; group 2 =0,2%; p=0,0006) were significantly more often developed in patients with type 2 diabetes.In the long-term follow-up period, death (group 1 =6,6%; group 2 =1,1%; p<0,0001), MI (group 1 =4,9%; group 2 =0,8%; p=0,0008), stroke (group 1 =7,7%; group 2 =1,5%; p<0,0001), ICA restenosis (group 1 =8,8%; group 2 =1,6%; p<0,0001), repeated emergency myocardial revascularization (group 1 =7,2%; group 2 =1,5%; p=0,0002), repeated emergency cerebral revascularization (group 1 =8,8%; group 2 =1,6%; p<0,0001) were significantly more often recorded in patients with type 2 diabetes.Kaplan-Meier curve analysis and its comparison using the log rank test revealed that the death, MI, and stroke were also significantly more often observed in patients with type 2 diabetes (p=0,0007, p=0,003, p<0,0001, respectively).Conclusion. Patients with type 2 diabetes who are referred for combined CE+CABG are at an increased risk of stroke, sternal wound infection and mediastinitis in the in-hospital postoperative period, as well as all adverse cardiovascular events in the long-term follow-up period