Obtaining Sulfur from Sulfur Hexafluoride and Studying the Sulfur Isotopes Properties by Using Vibrational Spectroscopy

Scheme of isotopically enriched SF[6] to elemental sulfur with orthorhombic modification conversion is offered. This scheme includes SF[6] reduction to Li2S by using lithium. The yield of isotopically enriched sulfur is not less than 97% with chemical purity not less than 99.9%. The results which show the dependence of the experimental frequencies in the vibrational spectra on the molecular weight of the sulfur isotope have been obtained

Separation of rare earth elements by zone recrystallization

The separation of holmium and cerium by zone recrystallization using a mixture of HoCl[3]6H[2]O and CeCl[3]6H[2]O was investigated. It is shown that holmium is enriched at the end of the crystal that the recrystallization zone moves to, while cerium is concentrated in the primary solidification zone. The possible reasons for the experimentally observed distribution of hydrated ions of cerium and holmium along the length of the ingot are discussed. Also the coefficients of enrichment and separation are calculated

Spectrophotometric Procedure for Fast Reactor Advanced Coolant Manufacture Control

The paper describes a spectrophotometric procedure for fast reactor advanced coolant manufacture control. The molar absorption coefficient of dimethyllead dibromide with dithizone was defined as equal to 68864 ± 795 lmole{-1}cm{-1}, limit of detection as equal to 0.583 10{-6} g/ml. The spectrophotometric procedure application range was found to be equal to 37.88-196.3 g. of dimethyllead dibromide in the sample. The procedure was used within the framework of the development of the method of synthesis of the advanced coolant for fast reactors

Influence of Adding Ammonium Bifluoride when Leaching Monazite Using Sulphur Acid

The following shows the results of the leaching of monazite concentrate with sulfuric acid in the presence of ammonium bifluoride. It was established that the addition of ammonium bifluoride increases the degree of the leaching monazite concentrate and allows the separation of phosphorous from a mixture of rare earth and radioactive elements

Lithium and magnesium isotopes fractionation by zone melting

The process of changing isotopic composition of the lithium and magnesium salts was studied by using the process of zone melting. It was founded in the paper that the process of separation of the lithium isotopes is more effective than for magnesium isotopes when the conditions of process were the same. The coefficients of isotopes separation were calculated and have the next value: [alpha]=1.006 for 26Mg isotope and [alpha]=1.0022 for {6}Li isotope

Study of sulfur isotopes by vibrational spectroscopy and quantum chemistry

The results show the dependence of the experimental and calculated frequencies in the IR- and Raman spectra from the molecular mass of the sulfur isotope. The effect of a sulfur isotope shifts on the change of thermodynamic parameters. The results obtained demonstrate that the quantum-chemical calculations are sensitive to the isotopic shifts in the vibrational spectra of sulfur isotopes and are able to assess changes in their thermodynamic properties

Quantum chemical study of the structure and properties of isotopically pure lead chalcogenides

In the present work the theoretical methods B3LYP/SDD, GGA and BP86/TZ2P were used for quantum-chemical calculations of lead chalcogenides. It is shown that these levels of theory are applicable for assessment of their geometric parameters, Raman and IR spectra and thermodynamic characteristics. It is shown that there are correlations between the experimental and calculated characteristics of lead sulphide, selenide and telluride. The influence of different isotopes of lead, sulphur, selenium and tellurium on the thermodynamic parameters and the Raman spectra for the lead chalcogenides is shown

Formation of organosilicon compounds in water purification processes

The study of the problem of removal of silicon ions of groundwater in water treatment processes and the ability of silicon ions to participate in the formation of silicon compounds that are resistant to physical and chemical effects is an urgent task, has practical significance for purification technologies developers. The aim of the research is the study of the formation mechanism of colloid organosilicon compounds in the water treatment process. Methods: photocolorimetry, pH measurement, titrometry, optical methods. Results. The authors investigated that the silicon ions have effect on the formation of colloidal organosilicon compounds of iron compounds whose presence in the groundwater reduces the performance of water treatment plants. It is shown that the silicon ions react with the organic substances of the humus origin to form stable colloidal compounds. The authors also defined the molar ratio of silicon ions and humic substances (critical micelle concentration) at which colloidal compounds are formed. The resulting molar ratio of silicon ions and humic substances is 7:2 respectively. We proposed a scheme for the formation of the sol and silicon compounds and defined the zeta potential which is -21 mV. We also demonstrated the formation of organosilicon compounds in the solution by mixing 2 solutions containing silicon ions and sodium humate with simultaneous determination of particle size. The maximum particle distribution changes within 30 minutes in the range of 50 to 70 nm during the formation of the organosilicon colloidal compounds. At the same time there is a coarsening of the particles, the percentage of particles with sizes ranging from 100 to 100,000 nm varies from 68 to 80 %

Formation of organosilicon compounds in water purification processes

Исследование проблемы удаления ионов кремния из подземных вод в процессах водоочистки и возможность ионов кремния участвовать в формировании кремнийорганических коллоидных соединений, устойчивых к физико-химическим воздействиям, является актуальной задачей и имеет практическую значимость для разработчиков водоочистных устройств. Цель работы: установить последовательность формирования кремнийорганических коллоидных соединений в процессе водоподготовки. Методы исследования: фотоколориметрия, рН-метрия, титрометрия, оптические методы. Результаты. Исследовано влияние ионов кремния на образование коллоидных кремнийорганических соединений железа, присутствие которых в подземных водах снижает производительность установок водоподготовки. Показано, что ионы кремния взаимодействуют с органическими веществами гумусового происхождения с образованием устойчивых коллоидных соединений. Определено мольное соотношение ионов кремния и гуминовых веществ (критическая концентрация мицеллообразования), при котором образуются коллоидные соединения. Полученное мольное соотношение ионов кремния и гуминовых веществ составляет 7:2 соответственно. Предложена схема образования золя кремнийорганических соединений и определен дзета-потенциал, значение которого составляет -21 мВ. Процесс образования кремнийорганических коллоидных соединений в растворе продемонстрирован экспериментом по смешению двух растворов, содержащих ионы кремния и гумата натрия, с одновременным определением размеров частиц. В процессе образования кремнийорганических коллоидных соединений максимум распределения частиц изменяется в течение 30 минут в интервале от 50 до 70 нм. При этом происходит укрупнение частиц и процентное содержание частиц с размерами от 100 до 100000 нм изменяется от 68 до 80 %.The study of the problem of removal of silicon ions of groundwater in water treatment processes and the ability of silicon ions to participate in the formation of silicon compounds that are resistant to physical and chemical effects is an urgent task, has practical significance for purification technologies developers. The aim of the research is the study of the formation mechanism of colloid organosilicon compounds in the water treatment process. Methods: photocolorimetry, pH measurement, titrometry, optical methods. Results. The authors investigated that the silicon ions have effect on the formation of colloidal organosilicon compounds of iron compounds whose presence in the groundwater reduces the performance of water treatment plants. It is shown that the silicon ions react with the organic substances of the humus origin to form stable colloidal compounds. The authors also defined the molar ratio of silicon ions and humic substances (critical micelle concentration) at which colloidal compounds are formed. The resulting molar ratio of silicon ions and humic substances is 7:2 respectively. We proposed a scheme for the formation of the sol and silicon compounds and defined the zeta potential which is -21 mV. We also demonstrated the formation of organosilicon compounds in the solution by mixing 2 solutions containing silicon ions and sodium humate with simultaneous determination of particle size. The maximum particle distribution changes within 30 minutes in the range of 50 to 70 nm during the formation of the organosilicon colloidal compounds. At the same time there is a coarsening of the particles, the percentage of particles with sizes ranging from 100 to 100,000 nm varies from 68 to 80 %

Search for an axion-like particle in radiative J/ψ decays

We search for an axion-like particle (ALP) a through the process ψ(3686)→π+π−J/ψ, J/ψ→γa, a→γγ in a data sample of (2.71±0.01)×109 ψ(3686) events collected by the BESIII detector. No significant ALP signal is observed over the expected background, and the upper limits on the branching fraction of the decay J/ψ→γa and the ALP-photon coupling constant gaγγ are set at 95% confidence level in the mass range of 0.165≤ma≤2.84GeV/c2. The limits on B(J/ψ→γa) range from 8.3×10−8 to 1.8×10−6 over the search region, and the constraints on the ALP-photon coupling are the most stringent to date for 0.165≤ma≤1.468GeV/c2