Optimization of parameters of multilayer diffraction gratings using needle variations

Background. The purpose of the work is to optimize the diffraction efficiency in the first diffraction order of a multilayer diffraction grating. Material and methods. Needle variations are used to optimize diffraction efficiency. Results. Computational experiments were performed, which showed that the addition of a second line in the grating period significantly increased the diffraction efficiency in the first diffraction order. Conclusions. The use of needle variations is applicable in the design of multilayer diffraction gratings

Monitoring the dustiness of the gymnasium

This article presents an experimental study of the concentration of fine dust in a covered sports facility using the example of a sports gym using a HANDHELD-3016 aerosol particle counter. The monitoring data of indoor air was analyzed and graphically presented in graphs of the integral function of the distribution of dust particles over the diameters. The concentration of fine dust at different time intervals during the training of the sports section was compared. The dependence of the distribution of dust particles over the measurement heights on the intensity of the workout was studied. Recommendations on improving air quality in a sports-type room during classes were provided. Changes in the indicators of external respiration during the training session was analysed

On Hydrated Strontium Hafnate

For the first time, strontium hafnate of the composition SrHfO3 · 2H2O was isolated from hafnium-containing alkali solutions. This compound was the only solid product of the reaction in the range of the strontium-to-hafnium molar feed ratios studied from 0.52:1 to 1.74:1 under various synthesis conditions (T = 40-145°C, 50.0-67.0 wt % NaOH). The compound crystallizes in the cubic system with a varied within 4.072-4.144 Å. Water enters the compound as molecules or hydroxide groups and insignificantly influences its structure. Dehydration decreases a

Crystal Structure and Properties of Potassium Hydroxostannate(IV) K2Sn(OH)6

A single-crystal X-ray investigation of potassium hydroxostannate(IV) K2Sn(OH)6 showed rhombohedral space group R3 with a = 6.545(1) Å and c = 12.808(3) Å. The Sn atom is surrounded by a slightly distorted octahedral array of six O atoms with Sn-O 2.068(1) Å. [Sn(OH)6]2- complex anions are linked by O-H⋯O hydrogen bonds 2.894(2) Å long. An X-ray diffraction powder pattern was indexed. IR absorption bands were assigned. Thermolysis of the hydroxostannate proceeds in three stages at 235, 362, and 495°C to split 2, 1/3, and 2/3 water molecules, respectively

Crystal structure and properties of potassium hydroxostannate(IV) K2Sn(OH)(6)

A single-crystal X-ray investigation of potassium hydroxostannate(IV) K2Sn(OH)(6) showed rhombohedral space group R.(3) over bar with a = 6.545(1) Angstrom and c = 12.808(3) Angstrom. The Sn atom is surrounded by a slightly distorted octahedral array of six Q atoms with Sn-O 2.068(1) Angstrom. [Sn(OH)(6)](2-) complex anions at e linked by O-H . . .O hydrogen bonds 2.894(2) Angstrom long. An X-ray diffraction powder pattern was indexed. IR absorption bands were assigned. Thermolysis of the hydroxostannate proceeds in three stages at 235, 362, and 495 degreesC to split 2, 1/3, and 2/3 water molecules, respectively

Crystal Structure and Properties of Potassium Hydroxostannate(IV) K2Sn(OH)6

A single-crystal X-ray investigation of potassium hydroxostannate(IV) K2Sn(OH)6 showed rhombohedral space group R3 with a = 6.545(1) Å and c = 12.808(3) Å. The Sn atom is surrounded by a slightly distorted octahedral array of six O atoms with Sn-O 2.068(1) Å. [Sn(OH)6]2- complex anions are linked by O-H⋯O hydrogen bonds 2.894(2) Å long. An X-ray diffraction powder pattern was indexed. IR absorption bands were assigned. Thermolysis of the hydroxostannate proceeds in three stages at 235, 362, and 495°C to split 2, 1/3, and 2/3 water molecules, respectively

ВЛИЯНИЕ АПРАМИЦИНА НА СТРУКТУРНО-ФУНКЦИОНАЛЬНЫЕ СВОЙСТВА ЭРИТРОЦИТОВ ПЕРИФЕРИЧЕСКОЙ КРОВИ КРЫС ПО ПАРАМЕТРАМ ОСМОТИЧЕСКИХ И КИСЛОТНЫХ ЭРИТРОГРАММ

Using automatic registration of erythrograms, the hypoosmotic and acid resistance of rat peripheral blood erythrocytes, modified with the antibiotic apramycin, were studied. It was found that a preliminary 30-minute incubation of a suspension of erythrocytes in physiological solution together with the antibiotic apramycin at a concentration of 0.2 mg/ml reduced the resistance of blood cells to hypoosmotic and acid conditions compared with intact erythrocytes. In a 0.45 % NaCl solution, erythrocytes modified with apramycin were more actively involved in the hemolytic process and 90 % of the cells were subjected to osmotic hemolysis for 90 s. In physiological saline with pH of 3.5-4.0, the latent period of acid hemolysis of erythrocytes modified with apramycin was 130 s. The number of erythrocytes hemolyzed in an acidic environment did not exceed 29 %. It was stated that the aminoglycoside antibiotic apramycin at a concentration of 0.2 mg/ml can interact with rat blood erythrocytes and cause latent changes in membrane structures and other organic components of cells in them, thereby reducing their resistance properties in hypoosmotic and acidic conditions.С помощью автоматической регистрации эритрограмм изучены гипоосмотическая и кислотная резистентность эритроцитов периферической крови крыс, модифицированных антибиотиком апрамицином. Установлено, что предварительная 30 минутная инкубация взвеси эритроцитов в физиологическом растворе вместе антибиотиком апрамицином в концентрации 0.2 мг/мл снижает резистентость клеток крови к гипоосмотическим и кислотным условиям по сравнению с интактными эритроцитами. В 0.45 % растворе NaCl эритроциты, модифицированные апрамицином, активнее вовлекались в гемолитический процесс и в течение 90 с осмотическому гемолизу подвергалось 90 % клеток. В физиологическом растворе с рН 3.5-4.0 латентный период кислотного гемолиза эритроцитов, модифицированных апрамицином, составил 130 с. Количество эритроцитов, гемолизированных в кислой среде, не превышало 29 %. Установлено, что аминогликозидный антибиотик апрамицин в концентрации 0.2 мг/мл может взаимодействовать с эритроцитами крови крыс и, вызывать в них скрытые изменения мембранных структур и других органических компонентов клеток, снижая тем самым их резистентные свойства в условиях гипоосмотической и кислой среды

Acid-Base Properties of Hydrous Hafnium Dioxide in Relation to the Pretreatment Temperature

Constants of acid-base equilibria at the HfO2 · aq/electrolyte interface are calculated. The number of surface hydroxo groups capable of deprotonation decreases with increasing pretreatment temperature of hydrous hafnium dioxide