Fine Chemical Technologies (E-Journal) / Тонкие химические технологии
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ВЗАИМОСВЯЗЬ ХИМИЧЕСКОЙ СТРУКТУРЫ УСКОРИТЕЛЕЙ ТИАЗОЛОВОГО РЯДА С ВУЛКАНИЗАЦИОННЫМИ СВОЙСТВАМИ ЭЛАСТОМЕРНЫХ КОМПОЗИЦИЙ
Get PDFThe quantum-chemical calculation of structures of sulfur vulcanization organic thiazole accelerators was performed. It was established that there is a correlation between the atomic electronegativity of nitrogen, the S–N length bond of and the rheokinetic properties of sulfur vulcanizates with Shungite and ZnO as activators. Moreover, scorching time was influenced on type of an activator. It should be noted that in the presence of Shungite under vulcanization began earlier than with ZnO except for MBT. So the strength of the physical adsorption of MBT on the surface of ZnO similars to Shungite.Проведен квантово-химический расчет структурных формул органических ускорителей серной вулканизации тиазолового ряда. Определены длины и углы связей, а также рассчитаны заряды атомов. Установлена взаимосвязь между электроотрицательностью атома азота, длиной связи S-N и реометрическими свойствами серных вулканизатов c шунгитом и оксидом цинка в качестве активаторов
ГИПЕРГРАФОВЫЕ МОДЕЛИ МОЛЕКУЛ УГЛЕВОДОРОДОВ И ИХ ПРИМЕНЕНИЕ В КОМПЬЮТЕРНОЙ ХИМИИ
Get PDFA new form of representing the structures of saturated hydrocarbons as hypergraphs of special kind is suggested. A vertex of such hypergraph corresponds to a carbon atom in the molecule, and a hyperedge is defined as a set of vertices corresponding to some fixed carbon atom and all carbon atoms bounded with it. The comparison of the traditional graph model and the suggested hypergraph model using definite quantitative criteria related to some tasks of computer chemistry is fulfilled. For these investigations some set of hydrocarbons presented by their structural formulae is used. In particular, different invariants and codes of graphs and hypergraphs were calculated and their degeneration on the given set of structures was studied and compared. Two models were also compared by the ability of some local vertex invariants derived from them to distinguish topologically nonequivalent vertices in the traditional graph model. It is shown that in all cases in accordance with the used criteria the hypergraph model is better than the graph model. Besides, a number of structure–property relationships on the base of invariants of the suggested hypergraphs was obtainedПредложен новый способ представления структур насыщенных углеводородов в виде гипер-графов специальной конструкции. Проведено сравнение традиционной графовой модели и предложенной гиперграфовой модели. Для этой цели введен ряд количественных критериев, характеризующих эффективность применения той или иной модели при решении опре-деленных задач компьютерной химии. Для исследований использована некоторая выборка угле-водородов, представленных своими структурными формулами. Показано, что по всем рассмотренным критериям гиперграфовая модель превосходит графовую. Кроме того, на основе инвариантов предложенных гиперграфов для соединений заданной выборки построен ряд корреляций «структура-свойство»
Влияние подложки на активационные параметры каталитического разрыва с-с-связи в молекуле пропановой кислоты
Get PDFThe effect of support on the activation parameters of C-C bond cleavage in a propanoic acid molecule was studied with DFT-PBE approach using the model of Pd9 cluster supported on (Al2O3)4 and (Al2O3)4(OH)2. Free activation energy is higher for Pd9/Al8O12 and Pd9/Al8O12(OH)2 (135-146 kJ∙mol-1 ) comparing to that of isolated Pd9 clusters (115-125 kJ∙mol-1 ). The effect of support is stronger (up to 31 kJ∙mol-1 ) for those structures, where the distance between Al8O12 and reactive palladium atoms is shorter. The energy of interaction between Pd9 and “dry” alumina compared to hydroxylated one (Al2O3)4(OH)2 is about two times less: 253-351 and 560-579 kJ∙mol-1 , respectively. The difference in energies is related to dependence of the energy of optimized structures on initial Pd9 location above alumina support. Despite that, activation parameters (Δ≠ G623) of C-C cleavage step differ slightly for (Al2O3)4 and (Al2O3)4(OH)2, from 1.3 to 5.6 kJ∙mol-1 . For all the models considered a carbon-carbon bond cleavage in a molecule of propanoic acid occurs as a threecentered interaction, viz. with participation of single Pd atomМетодом функционала плотности PBE, на примере кластера палладия Pd9, нанесенного на подложку из (Al2O3)4 и (Al2O3)4(OH)2 - модели оксида алюминия, оценено влияние носителя катализатора на активационные параметры стадии разрыва связи углерод-углерод в молекуле пропановой кислоты. Благодаря взаимодействию между Pd9 и носителем каталитическое поведение палладия определяется не только координационной доступностью атомов металла, но и расстоянием между ним и подложкой
Автомодельные решения гидродинамических уравнений нелокальной физики
Get PDFFor linear partial differential equations there are various techniques for reducing the partial differential equations (PDE) to the ordinary differential equations (ODE) or at least to equations in a smaller number of independent variables. These include various integral transforms and eigenfunction expansions. Usually such techniques are not applicable in dealing with nonlinear partial differential equations. From this point of view the presented approach is much more interesting. It identifies equations for which the solution depends on certain groupings of the independent variables rather than depending on each of the independent variables separately. The name of these solutions, self-similar, comes from the fact that the spatial distribution of the characteristics of motion remains similar to itself at all times during the motion. Roughly speaking, the idea is to look whether the solution of a problem u(x, y) can be collapsed in a function u(x, y) = U(y / f (x)). The function f (x) may be found by substitution in the PDE, in order to obtain an ODE for U . Self-similar solutions of the non-local equations describing the explosion with the spherical symmetry are investigated for the case of the astrophysical applications. Namely, in the quasi-stationary Hubble regime only the implicit dependence on time for the unknown values exists. It means that for the intermediate (Hubble) regime the complicated PDE set can be transformed in the set ODE. This possibility can be realized also in the case if the self-similar solutions exist. The mentioned self-similar solutions are found for Hubble regime.Получены автомодельные решения локальных и нелокальных гидродинамических уравнений в самосогласованном гравитационном поле для сферически симметричного случая. Установлено, что нелокальные уравнения, в отличие от локальных, описывают более широкий спектр возможных режимов движения материи после взрыва, в том числе Хаббловское расширение
К вопросу классификации плоских четырехугольных диаграмм
Get PDFAnalysis of classifications of planar quadrangular diagrams published in the literature was carried out. These classifications deal with projections of chemical equilibrium surfaces in a quarternary system, with ternary intermutual systems containing liquid and solid solutions between constituent salts and also with graphical representation of response surfaces. The synthesis of the complete set of topological types of planar quadrangular diagrams was carried out. The complete set includes 98 types, which differ in boundary and inner simple singular points (elliptic and hyperbolic); the total amount of subtypes is 120. The subtypes of the diagrams may differ in the mutual arrangement of either boundary or both boundary and inner singular points. In previously published classifications, repeating diagram structures and unstable structures were revealed. The most accurate results are achieved by a formalized procedure of synthesis of a topologically possible set of planar quadrangular diagrams. By “formalized procedure” we mean the use of a specific program for variants enumeration of possible mutual arrangement of singular points in planar quadrangular diagrams. This procedure in the most correct way allows to take into account diagrams differing in the mutual arrangement of not only boundary, but also inner singular points.Р ассмотрены нелокальные закономерности четырехугольных диаграмм изолиний скалярных свойств; проведен анализ и сопоставление существующих классификаций таких диаграмм; обсуждены различные группы подтипов диаграмм
Влияние стеариновой кислоты на поверхностные свойства эластомерных композитов на основе бутадиен-стирольных каучуков
Get PDFIt has been shown that stearic acid has specific effect on the formation of surface properties of butadiene-styrene rubber produced by polymerization in solution, and of rubbers based on it. When stearic acid content is up to 1 wt. parts per 100 wt. parts of rubber, surface tension of samples is reduced, and at higher content the surface tension is increased. These features can be useful in predicting the technological behavior of rubber compositions during their processing.Показано специфическое влияние стеариновой кислоты на формирование поверхностных свойств бутадиен-стирольного каучука растворной полимеризации, и резин на его основе. При содержании стеариновой кислоты до 1 мас. ч. на 100 мас. ч. каучука поверхностное натяжение образцов снижается, а при увеличении ее содержания может повышаться. Выявленные особенности могут быть полезны при прогнозировании технологического поведения резиновых смесей в процессе их переработки
Разработка методических основ построения организационной компоненты бизнес-модели компании
Get PDFNumerous studies of the concept of a business model allow to formulate the most expedient structure of elements and the structure of this new administrative category. At the same time, the majority of researchers casually or intentionally exclude from attention the task of the organization of functioning of a business model.Многочисленные исследования концепции бизнес-модели позволяют сформулировать наиболее целесо-образные состав элементов и структуру этой новой управленческой категории. Вместе с тем, большинство исследователей случайно или намеренно исключают из внимания задачу организации функционирования бизнес-модели
К нелокальной теории зарядовых и спиновых взаимодействий в волнах и частицах
No full textThe theory of the charge – spin interaction in waves in the frame of non-local quantum hydrodynamics is considered. The electron charge inner structure is investigated using the non-local physical description. From calculations follow that electrons can be considered like charged balls (shortly CB model) which charges are concentrated mainly in the shell of these balls. The possible direction deviation of the spin momentum and the magnetic momentum is taken into account.В рамках нелокальной квантовой гидродинамики построена теория взаимодействия в волнах зарядовых и спиновых возбуждений. Исследована внутренняя зарядовая структура электрона на основе нелокального описания. Из расчетов следует, что внутреннее распределение заряда электрона отвечает модели шара, заряд которого сосредоточен в основном в окрестности оболочки шара. В расчетах учитывается возможное отклонение спина от направления магнитного момента
Получение углеродных нановолокон из газа электрокрекинга органического сырья в реакторе «ссыпного типа»
Get PDFIt is shown that the “bulk type” reactor proposed for obtaining carbon nanofibers from carbon monoxide can be used to obtain carbon nanofibers from organic raw materials electrocracking gas without changing the shape of the reaction cell. The “bulk type” reactor allows to combine the process of obtaining carbon nanofibers and separation of the formed products, and this allows to simplify the technology of carbon nanofibers. Varying the speed of the introduction of the catalyst in the synthesis zone under the same process conditions (temperature, volumetric gas flow rate, the composition of the gas) enables to obtain products with different characteristics. Using the maсrokinetics peculiarities of topochemical reactions of hydrocarbons decomposition it is possible to provide uninterrupted continued operation of the reactor and the obtaining of a product with the desired properties.Показано, что реактор «ссыпного типа», предложенный для получения углеродных нановолокон (УНВ) из монооксида углерода, может быть использован для получения УНВ из газа электрокрекинга органического сырья без изменения формы реакционной ячейки. Используя макрокинетические особенности протекания топохимической реакции разложения углево-дородов, можно обеспечить бесперебойную длительную работу реактора и получение продукта с заранее заданными свойствами
Создание пролекарств на основе антрациклиновых антибиотиков
Get PDFAlthough anthracycline antibiotics are widely used in the treatment of cancer, their use is limited due to severe side-effects, including irreversible cardiotoxicity and multi-drug resistance of tumor cells. One of the promising approaches towards “ideal” anthracycline is the creation of anthracycline-based prodrugs, i.e. compounds that are less active than the parent drug (or inactive) and are converted in its active form through a metabolic process. The main goal of the development of anthracycline prodrugs is to increase the selectivity of the drug (doxorubicin or daunorubicin) towards tumor cells with simultaneous decrease in toxicity to normal cells. With this aim different types of anthracycline prodrugs were designed targeting such specific characteristics of tumor cells as lower pH and oxygenation level in comparison with normal cells, higher content of different enzymes etc. Also two-stage “enzyme-prodrug” strategies which include the selective introduction of the enzyme into the tumor cells on the first step and administration of the prodrug which is the substrate for this enzyme on the second step are developed. These strategies are classified depending on the method of “introduction” of the enzyme into tumor cells: antibody-directed enzyme prodrug therapy (ADEPT), virus-directed enzyme prodrug therapy (VDEPT) and genedirected enzyme prodrug therapy (GDEPT). The review covers recent achievements in the field of creation of different types of anthracycline prodrugsВ обзоре рассмотрены достижения последних лет в области создания пролекарств на основе антрациклиновых антибиотиков. Описаны основные принципы создания пролекарств, в том числе, различия в биологии и метаболизме опухолевых клеток, которые позволяют конструировать пролекарства, селективно расщепляющиеся в опухолевых клетках. Рассмотрены двухступенчатые стратегии «фермент-пролекарство» (ADEPT/GDEPT/VGEPT)