Effect of anodizing regimes on the volume expansion factor of the oxide films

The volume expansion factor of porous alumina, formed by through anodizing of an Al foil in ox- alic and sulphuric acid has been studied. The thickness of obtained porous alumina films was measured by a mechanical profilometer with a computer signal processing. The volume expansion factor of porous alumina varied from 1.35 to 1.65. Linear dependences were obtained for the vol- ume expansion factor of porous alumina versus the anodizing voltage and the ionic current density logarithm versus the inverse volume expansion factor. Unlike oxide formation in sulphuric acid, these dependences have two subsequential rectilinear regions in oxalic acid

Investigating the light stability of solid-solution-based AgCl-AgBr and AgBr-TlI crystals

For the development of mid-infrared fiber-optical elements, one needs light-stable, flexible materials that are transparent within this spectral band. Solid solutions of silver and monadic thallium halides prove to be the most suitable crystalline media for these needs. We study the light stability variation of high-purity AgCl1-xBrx(0 ≤ x ≤ 1) and Ag1-xTlxBr1-xIx (0 ≤ x ≤ 0.05) crystals by measuring the optical transmission change as functions of the composition and UV exposure time. The former is executed in a broad spectral range from 6500 - 350 cm-1, within which we choose three wavelengths to trace the transmission change. For thalliummonoiodide-containing samples, an effect is observed that we assumed to be translucence. © 2016 Chinese Optics Letters

Features of the porous morphology of anodic alumina films at the initial stage of disordered growth

A characteristic feature of disordered porous anodic film growth at the initial stage of aluminum anodizing was revealed by varying the electrolyte type and anodizing voltage. The samples were obtained by the electrochemical oxidation of thin aluminum films (100 nm thick) on SiO2/Si substrates in a 0.3 M oxalic acid at 10–50 V and were studied by SEM. The ImageJ analysis of the images revealed the simultaneous development of two large groups of pores: major pores with a large diameter and minor pores with a smaller diameter. When anodizing in oxalic acid at 10–50 V, it has been shown that the ratio of the diameters of the major and minor pores remains constant and is about 1.17. Using a geometric model, we demonstrated that the centers of the minor pores are located inside the elementary hexagonal cell formed by the centers of the major pores. Moreover, our results are very close to the theoretical value of 2/√3. At the initial stage of disordered pore growth, the development of minor pores rather than major pores is not a random process and is determined by energy-efficient conditions for the development of pores inside the hexagonal cells formed by the major pores. The increase in compressive mechanical stress in the anodic film leads to an interruption in the development of such pores

Effect of anodic oxygen evolution on cell morphology of sulfuric acid anodic alumina films

The purpose of this work was to study and analyze the effect of electrolyte temperature and anodization voltage on cell morphology of thin films of sulfuric acid anodic alumina formed on substrates of different nature, such as SiO2/Si, glass-ceramic, glass substrates, and polished aluminum. The data obtained demonstrated that the thermal conductivity of the substrate in the voltage range from 12 to 14 V affected a pore diameter (dpore) in anodic films. Depending on the substrate type, dpore increased in the following order: glass > glass- ceramic > SiO2/Si > aluminum. It was found that the anodizing voltage (Ua) of 16 V was a turning point for anodic films obtained in sulfuric acid after which the slope of the lines for both dpore and Dinter (interpore distance) vs. Ua changed. This behavior might be explained by the occurrence of the overpotential enough for the beginning of the oxygen evolution reaction. We assumed that the oxygen evolution on aluminum oxide surface at the pore bottom at Ua> 16 V results in an increase in acid concentration in the solution and, consequently, in rise in acidic nature of the electrolyte and increase in the dissolution rate of the oxide layer of pore walls

Applying Aniline for P-doping of PEDOT:PSS Films to Improve Their Conductivity and Efficiency of Perovskite Solar Cells

Poly(3,4- ethylenedioxythiophene):polystyrene sulfonate (PEDOT: PSS) is responsible for hole extraction efficiency and hole transport in the perovskite solar cell structure. The inclusion of PSS reduces the conductivity of the PEDOT films, which inhibits hole transport and results in a low photo current of the perovskite solar cell. In this work, an aniline solution was used as an additive in the PEDOT: PSS thin film to increase electrical conductivity. Two different methods were used to incorporate the additive: surface and volume treatment. The results show that the surface treatment with aniline solution can significantly increase the conductivity of PEDOT: PSS film. Moreover, the photoconversion efficiency of the perovskite solar cell with such a PEDOT: PSS layer is increased 1.5 times compared to the untreated one

FEATURES OF DIAGNOSTIC AND THERAPEUTIC TACTICS FOR BLUNT ABDOMINAL TRAUMA WITH DAMAGE TO THE PANCREAS

Abstract. Injuries of pancreas in the closed abdominal trauma remain the one of most challenging issues in diagnosis and choice of optimal therapy.Objectives. To analyze clinical results of the improved diagnostic and treatment tactics in patients with blunt abdominal trauma and damage to the pancreas.Material and methods. We report the results of treatment for 141 patients with pancreatic trauma treated from 1991 to 2015 at City Hospital No. 3 and City Hospital No. 40. All patients were divided into 2 groups. These groups were formed according to the time factor. The groups were comparable in age, gender, and pancreatic trauma severity. The study group consisted of 59 patients, treated in 2004-2015, and the comparison group consisted of 82 patients (1991–2003). The advanced diagnostic and treatment algorithm for the study group included modern instrumental diagnostic methods, such as ultrasound, computed tomography, diagnostic laparoscopy and improved surgical tactics to lower indications for omental plug, omentobursostomy, suturing capsule of pancreas and cholecystostomy.Results. This algorithm reduced the duration gap between hospitalization and surgery averagely from 10.7 to 4.0 hours, and the modified treatment tactics decreased the incidence of septic complications from 15.8% to 6.8%, and the mortality from 27.6% to 16.9%.Conclusion. As a rule, methods of radiodiagnosis detect only indirect signs of pancreatic injury in blunt abdominal trauma. It is advisable to perform omental plugging only as medical tactics of «damage control»

Recognitionand Analysis of Microstructure Parameters of Porous Anodic Films Using ImageJ

The most important parameters that characterize the microstructure of the films and determine the possibility of their use as porous templates are the pore diameter, porosity, and ordering of the porous structure. Therefore, to increase the efficiency of the use of porous anodic alumina films, it is important to investigate the effect of the formation modes on the microstructure. The aim of this work was to choose and optimize a model for processing experimental data obtained by scanning electron microscopy in the ImageJ to determine the parameters of the microstructure of porous films. The work shows the result of SEMimage analysis and obtains plots of pore diameter distribution by size and determines the diameter of the main pores

Stored charge and its influence on properties of anodic alumina films

In porous and barrier-type anodic alumina films, the stored charge has electronic nature and it plays a significant role in the process of aluminum anodizing. The charge stored can modify the distribution of local field generated by a voltage applied and thus it can affect the oxide growth. The method for the investigation of thermally activated defects in anodic alumina films by reanodizing technique was also described. It was applied for computation of activation energy of electron traps in barrier layer for sulfuric and oxalic acid alumina films and concentration of the traps

ДИАГНОСТИКА СТЕНОЗОВ СТВОЛА ЛЕВОЙ КОРОНАРНОЙ АРТЕРИИ И ПЕРЕДНЕЙ НИСХОДЯЩЕЙ КОРОНАРНОЙ АРТЕРИИ С ПОМОЩЬЮ ТРАНСТОРАКАЛЬНОЙ ЭХОКАРДИОГРАФИИ

Purpose. To detect the potential of different qualitative, semi-quantitative and quantitative transthoracic Doppler signs for successful evaluation of stenotic left main coronary artery (LMCA) and left anterior descending artery (LAD).Materials and methods. 173 patients (52±10 years; 149 men) with chest pain, sinus rhythm and scheduled quantitative coronaryangiography (CAG) were evaluated at rest by non-contrast transthoracic echocardiography (TT E). LMCA and proximal (p), mid (m) and distal (d) parts of the LAD were examined. The Doppler signs of coronary stenosis >50 % were determined as follows: 1 – local Doppler aliasing with the Nyquist limit set at 60 cm/s; 2 – maximal peak diastolic velocity (Vpd) >60 cm/s; 3 – ratio of stenotic/prestenotic Vpd >2.0; 4 – stenosis >50 % according to flow continuous equation: stenosis, % = 100 × (1 – prestenotic VTId / stenotic VTId), where VTId – diastolic time velocity integral. CAG was performed within 1 week after TT E. Stenosis >50 % of diameter reduction was considered as significant.Results. Sensitivity (Sens), specificity (Sp) and diagnostic accuracy (Ac) of different Doppler stenotic signs for stenotic LMCA andLAD are presented in Table 1. Thus, TT E is a method for correct evaluation of stenotic LMCA and LAD. Quantitative ratio of stenotic to prestenotic coronary flow velocities is a more sensitive sign for detecting stenosis >50 %, than qualitative and semi-quantitative evaluation of maximal coronary flow velocity only.Цель. Оценить возможности неконтрастной трансторакальной эхокардиографии (ТТ ЭхоКГ) для качественной, полуколичественной и количественной диагностики стенозов ствола левой коронарной артерии (ЛКА) и передней нисходящей коронарной артерии (ПНА).Материалы и методы. ТТ ЭхоКГ выполнена у 173 человек (средний возраст 52±10 лет; 149 мужчин) с болью в левой половине грудной клетки, направленных в стационар для проведения коронарной ангиографии (КАГ). Исследован ствол ЛКА, проксимальный (пр/3), средний (ср/3) и дистальный (д/3) сегменты ПНА. Доплерографическими признаками стенозирования >50 % считали: 1 – локальный aliasing при использовании предела Найквиста 60 см/с; 2 – максимальную пиковую диастолическую скорость корнарного кровотока (Vpd) >60 см/с; 3 – отношение стенотическая Vpd / престенотическая Vpd >2,0; 4 – стеноз >50 % в соответствии с уравнением непрерывности потока: стеноз, % = 100 % × (1 – престенотический VTId / стенотический VTId), где VTId – интеграл скорости кровотока в диастолу. КАГ была проведена в течение 1 недели после ТТ ЭхоКГ; стенозы определяли как значимые, если уменьшение диаметра сосуда превышало 50 %.Результаты. Чувствительность (Ч), специфичность (Сп) и диагностическая точность различных доплерографических признаков для выявления стенозов ЛКА и ПНА представлены в таблице 1. Таким образом, ТТ ЭхоКГ является корректным неинвазивным методом диагностики стенозов ЛКА и ПНА. Количественное сравнение скоростей кровотока в престенотическом и стенотическом участках является более чувствительным доплеровским признаком стенозования >50 %, чем качественная и полуколичественная оценка стенозирования по максимальной скорости кровотока

Математическая модель VPN в сети электросвязи специального назначения

The purpose of the article is to develop a mathematical model of VPN in communication networks of special purpose, which allows to determine the margin of throughput, for scheduled VPN-tunnels. In contrast to the well-known approaches to estimating the bandwidth margin (hose model of VPN), the developed model takes into account the class of transmitted traffic. The developed model is adequate with an accuracy of 0.95. The materials presented in the article are original and can be used when planning VPN-tunnels in a special purpose telecommunication network.Разработана математическая модель VPN в сети электросвязи специального назначения, позволяющая определить запас по пропускной способности для планируемых VPN-туннелей. В отличие от известных подходов оценки запаса по пропускной способности (потоковая модель VPN) предлагаемая модель учитывает класс передаваемого трафика. Модель является адекватной с точностью 0,95. Материалы, представленные в статье, являются оригинальными и могут быть использованы при планировании VPN-туннелей в сети электросвязи специального назначения