База данных: Статьи
Страница 2, Результатов: 13
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11.
Подробнее
24
M97
Mussina, А. S.
Development of the conditions for strong thallium amalgam. [Текст] / А. S. Mussina // News of national academy of sciences of the republic of Kazakhstan. . - 2021. - №3. - P. 65-70
ББК 24
Рубрики: chemistry
Кл.слова (ненормированные):
thallium amalgam -- chemical preparation -- storage -- decomposition -- sulfuric acid -- water -- wash liquid
Аннотация: It has been established that lNH2SO4 solution and distilled water can be used as a protective medium for a long-term storage (30-40 days) of thallium amalgam of eutectic composition (8.6 mas.%), without sliming of its surface and an insignificant change of its concentration. An inverse dependence between the decomposition reaction rate and the ratio of the solution volume per unit of the contact surface (V:S), which corresponds to the height of the liquid layer (h) above the amalgam, is observed. At h ~ 2.5 cm and higher, the reaction rate becomes stabilized. The value of metal loss during its storage for 10-15 days does not exceed 0.5-1.0 mas.% of the initial thallium content in the amalgam. It has been shown that the rate of dissolution of thallium from amalgam is rather low, and in sulfuric acid solution it is only slightly higher than that in water with all S:V ratios. A similar picture is observed upon thallium amalgam decomposition in the same media in an open vessel; the difference consists only in a higher K value (Table 4). Thus, with S:V = 1:2.5, in an open vessel K in lNH2SO4 makes up 10,5.1011 mol/cm2.sec, and in H2O – 7.3.1011 mol/cm2.sec, whereas in a closed vessel K in lNH2SO4 makes up 1,9.1011 mol/cm2.sec, and in H2O – 1.5.1011 mol/cm2.sec. For 40 days of thallium amalgam (8.54 mas.%) storage in 1NH2SO4 the loss of thallium has been 1.3 mas.%, and in the distilled water - 1 mas.%. The quantity of the dissolved metal increases in proportion to the experiment duration, which is characteristic for a zero-order reaction, and this dependence is observed for all S:V ratios from 1:1 to 1:7. Besides, a possibility to use some saturated hydrocarbons, wherein no sliming of thallium amalgam occurs, as a protective wash liquid has been shown.
Держатели документа:
WKU
Доп.точки доступа:
Baitasheva, G.U.
Myrzakhmetova, N.О.
Tagabergenova, Zh.A.
Gorbulicheva , E.P.
M97
Mussina, А. S.
Development of the conditions for strong thallium amalgam. [Текст] / А. S. Mussina // News of national academy of sciences of the republic of Kazakhstan. . - 2021. - №3. - P. 65-70
Рубрики: chemistry
Кл.слова (ненормированные):
thallium amalgam -- chemical preparation -- storage -- decomposition -- sulfuric acid -- water -- wash liquid
Аннотация: It has been established that lNH2SO4 solution and distilled water can be used as a protective medium for a long-term storage (30-40 days) of thallium amalgam of eutectic composition (8.6 mas.%), without sliming of its surface and an insignificant change of its concentration. An inverse dependence between the decomposition reaction rate and the ratio of the solution volume per unit of the contact surface (V:S), which corresponds to the height of the liquid layer (h) above the amalgam, is observed. At h ~ 2.5 cm and higher, the reaction rate becomes stabilized. The value of metal loss during its storage for 10-15 days does not exceed 0.5-1.0 mas.% of the initial thallium content in the amalgam. It has been shown that the rate of dissolution of thallium from amalgam is rather low, and in sulfuric acid solution it is only slightly higher than that in water with all S:V ratios. A similar picture is observed upon thallium amalgam decomposition in the same media in an open vessel; the difference consists only in a higher K value (Table 4). Thus, with S:V = 1:2.5, in an open vessel K in lNH2SO4 makes up 10,5.1011 mol/cm2.sec, and in H2O – 7.3.1011 mol/cm2.sec, whereas in a closed vessel K in lNH2SO4 makes up 1,9.1011 mol/cm2.sec, and in H2O – 1.5.1011 mol/cm2.sec. For 40 days of thallium amalgam (8.54 mas.%) storage in 1NH2SO4 the loss of thallium has been 1.3 mas.%, and in the distilled water - 1 mas.%. The quantity of the dissolved metal increases in proportion to the experiment duration, which is characteristic for a zero-order reaction, and this dependence is observed for all S:V ratios from 1:1 to 1:7. Besides, a possibility to use some saturated hydrocarbons, wherein no sliming of thallium amalgam occurs, as a protective wash liquid has been shown.
Держатели документа:
WKU
Доп.точки доступа:
Baitasheva, G.U.
Myrzakhmetova, N.О.
Tagabergenova, Zh.A.
Gorbulicheva , E.P.
12.
Подробнее
24
N94
Nurdillayeva, R. N.
Dissolution of stanless steel in sodium chloride solution at polarization by non-stationary current. [Текст] / R. N. Nurdillayeva // News of national academy of sciences of the republic of Kazakhstan. . - 2021. - №3. - P. 75-81
ББК 24
Рубрики: chemistry
Кл.слова (ненормированные):
stainless steel -- titanium electrode -- alternating current -- iron (II) ions -- chromium (III)ions -- current density -- and current efficiency
Аннотация: Stainless steel is in great demand due to its mechanical strength, heat resistance, and resistance to corrosive environments. This article presents the result of a study of the electrochemical dissolution behavior of a stainless steel electrode (12X18H10T) at polarization by 50 Hz alternating current in a neutral medium (NaCl). Preliminary experiments have shown that the main processes do not take place when two stainless steel electrodes are polarized with an alternating current. It was observed that by the polarization of the “stainless steel – titanium” pair electrodes with alternating current, the alloy is intensively dissolved with the formation of iron (II) and chromium (III) ions. This is due to the "valve" properties of the oxide layer formed on the surface of the titanium electrode. A change in the value of the current density of the titanium and steel electrodes significantly affects the process of electrochemical dissolution of the alloy. At high current densities, the dissolution rate of the alloy decreases due to the deterioration of the current correcting properties of titanium. With an increase in the electrolyte concentration, the current efficiency is reduced as salt passivation occurs. A maximum value of the current efficiency of dissolution of stainless steel was observed at a current frequency of 50 Hz. High frequencies of the alternating current do not provide an adjustable duration of the anodic half-cycle for the oxidation reaction due to the frequent change of half-cycles of the alternating current. It was observed that increasing the temperature of the electrolyte reduces the current efficiency of the electrochemical dissolution of stainless steel electrodes. The effects of main electrochemical parameters on the electrolysis process have been investigated, and the optimal conditions of the alloy dissolution were established (іТі = 60 kA/m2, іSS = 800 A/m2, [NaCl] = 2.0 M, t = 30, ν = 50 Hz.).
Держатели документа:
WKU
Доп.точки доступа:
Sauirbay, Zh.G.
Bayeshov, A.B.
N94
Nurdillayeva, R. N.
Dissolution of stanless steel in sodium chloride solution at polarization by non-stationary current. [Текст] / R. N. Nurdillayeva // News of national academy of sciences of the republic of Kazakhstan. . - 2021. - №3. - P. 75-81
Рубрики: chemistry
Кл.слова (ненормированные):
stainless steel -- titanium electrode -- alternating current -- iron (II) ions -- chromium (III)ions -- current density -- and current efficiency
Аннотация: Stainless steel is in great demand due to its mechanical strength, heat resistance, and resistance to corrosive environments. This article presents the result of a study of the electrochemical dissolution behavior of a stainless steel electrode (12X18H10T) at polarization by 50 Hz alternating current in a neutral medium (NaCl). Preliminary experiments have shown that the main processes do not take place when two stainless steel electrodes are polarized with an alternating current. It was observed that by the polarization of the “stainless steel – titanium” pair electrodes with alternating current, the alloy is intensively dissolved with the formation of iron (II) and chromium (III) ions. This is due to the "valve" properties of the oxide layer formed on the surface of the titanium electrode. A change in the value of the current density of the titanium and steel electrodes significantly affects the process of electrochemical dissolution of the alloy. At high current densities, the dissolution rate of the alloy decreases due to the deterioration of the current correcting properties of titanium. With an increase in the electrolyte concentration, the current efficiency is reduced as salt passivation occurs. A maximum value of the current efficiency of dissolution of stainless steel was observed at a current frequency of 50 Hz. High frequencies of the alternating current do not provide an adjustable duration of the anodic half-cycle for the oxidation reaction due to the frequent change of half-cycles of the alternating current. It was observed that increasing the temperature of the electrolyte reduces the current efficiency of the electrochemical dissolution of stainless steel electrodes. The effects of main electrochemical parameters on the electrolysis process have been investigated, and the optimal conditions of the alloy dissolution were established (іТі = 60 kA/m2, іSS = 800 A/m2, [NaCl] = 2.0 M, t = 30, ν = 50 Hz.).
Держатели документа:
WKU
Доп.точки доступа:
Sauirbay, Zh.G.
Bayeshov, A.B.
13.
Подробнее
3
S81
Starovoitov, E. I.
Bending of an elastic three-layer plate with a hole connected to the soil foundation [Текст] / E. I. Starovoitov, M. A. Zhuravkov, P. F. Pronina // Известия Национальной Академии наук Республики Казахстан. - 2021. - №1. - Р. 164-171
ББК 3
Рубрики: Техника
Кл.слова (ненормированные):
трехслойная пластина с отверстиями -- перемещения -- напряжения -- грунтовое основание
Аннотация: Актуальность данной работы объясняется востребованностью разработки механических и математических моделей и методов расчета напряженно-деформированного состояния элементов конструкции сэндвича. Дана постановка краевой задачи о деформировании круглой многослойной плиты с центральным отверстием, соединенным с грунтовым основанием. Для описания кинематики пакета асимметричных пластин приняты гипотезы ломаной линии. В относительно толстом легком ядре норма не меняет длину, остается прямой, а поворачивается на некоторые дополнительные углы. Почвенная основа – туф, крупнозернистый грунт, гранит и гнейс. Реакция подшипника описывается моделью Винклера. Система уравнений равновесия получена вариационным методом. Ее решение записывается функциями Кельвина при перемещении. Проведен количественный параметрический анализ перемещений и напряжений в плите, показывающий их зависимость от типа грунтового основания
Держатели документа:
ЗКУ
Доп.точки доступа:
Zhuravkov, M. A.
Pronina, P. F.
S81
Starovoitov, E. I.
Bending of an elastic three-layer plate with a hole connected to the soil foundation [Текст] / E. I. Starovoitov, M. A. Zhuravkov, P. F. Pronina // Известия Национальной Академии наук Республики Казахстан. - 2021. - №1. - Р. 164-171
Рубрики: Техника
Кл.слова (ненормированные):
трехслойная пластина с отверстиями -- перемещения -- напряжения -- грунтовое основание
Аннотация: Актуальность данной работы объясняется востребованностью разработки механических и математических моделей и методов расчета напряженно-деформированного состояния элементов конструкции сэндвича. Дана постановка краевой задачи о деформировании круглой многослойной плиты с центральным отверстием, соединенным с грунтовым основанием. Для описания кинематики пакета асимметричных пластин приняты гипотезы ломаной линии. В относительно толстом легком ядре норма не меняет длину, остается прямой, а поворачивается на некоторые дополнительные углы. Почвенная основа – туф, крупнозернистый грунт, гранит и гнейс. Реакция подшипника описывается моделью Винклера. Система уравнений равновесия получена вариационным методом. Ее решение записывается функциями Кельвина при перемещении. Проведен количественный параметрический анализ перемещений и напряжений в плите, показывающий их зависимость от типа грунтового основания
Держатели документа:
ЗКУ
Доп.точки доступа:
Zhuravkov, M. A.
Pronina, P. F.
Страница 2, Результатов: 13