747 research outputs found
Structure of 2-Methyl-5,6,7-triphenyl-6,7-dihydropyrazolo[2,3-\u3cem\u3ea\u3c/em\u3e]pyrimidine
C25H21N3, Mr = 363.46, monoclinic, P21/n, a = 9.245 (2), b = 23.502 (5), c = 9.340 (2) Å, β= 103.50(3)°, V=1973.3(2) Å3, Z=4, Dx= 1.220 (2) g cm-3, λ (Mo Kα )= 0.71069 Å, μ = 0.068 cm-1, F(000) = 768, T= 292 K, R = 0.091 for 1442 unique observed reflections. The dihydropyrimidine ring adopts a distorted sofa conformation. The aryl substituents on the saturated C atoms have an axial orientation
Determination of Different Biological Factors on the Base of Dried Blood Spot Technology
It is well-known that distinct biological indices (analytes) have distinct
variability. We try to use some mathematical algorithms to pick out a set of
blood parameters which give an opportunity to retrieve the initial volume of
the blood spotted, and use it to calculate exact concentrations of analyts
interesting to a physician. For our analysis we used the database of
biochemical blood parameters obtained in Russian Scientific Center of
Roentgen-Radiology during 1995-2000, which includes more than 30000 of
patients.Comment: 5 page
One-pot three-component synthesis of 3-cyano-4-methyl-2,6-dioxopyridine amino enones
(Z)-5-(Arylaminomethylidene)-4-methyl-2,6-dioxo-1,2,5,6-tetrahydropyridine-3-carbonitriles were obtained by three-component condensation of 4-methyl-2,6-dioxo-1,2,5,6-tetrahydropyridine-3-carbonitrile with aromatic amines and trimethyl orthoformate in DMF. According to X-ray data, in the solid phase they exist as amino enone tautomer
Determining Optimal Mining Work Size on the OpenCL Platform for the Ethereum Cryptocurrency
In terms of cryptocurrency, mining is a process of creating a new transaction block to add it to the blockchain. The cryptocurrency protocol should ensure the reliability of new transaction blocks. One of the popular mining protocols is the Proof-of-Work protocol, which requires the miner to perform a certain work to verify its right to add a new block into the blockchain. To perform this work, high-performance hardware is used, such as GPU. On the program level, hardware needs special computing framework, for example, CUDA or OpenCL. In this article, we discuss Ethereum cryptocurrency mining using the OpenCL standard. The Ethereum cryptocurrency is the most popular cryptocurrency with GPU-based mining. There are several open-source implementations of the Ethereum cryptocurrency miners. The host-part of the OpenCL-miner is considered, which makes the research results independent of the mining algorithm and allows using the results of the research in the mining of other cryptocurrencies. During the research, we have found the problems, which lead to mining productivity loss, and we are looking for the ways to resolve these problems and thus increase mining performance. As part of solving these problems, we have developed the algorithm for the functioning of the miner and proposed the methodology of determining the optimal size of OpenCL work, which allows to reduce the impact of problems found and achieve maximum mining productivity using OpenCL framework
2-Hydroxyimino-N′-[1-(2-pyridyl)ethylidene]propanohydrazide
The title compound, C10H12N4O2, features an intramolecular N—H⋯N hydrogen bond formed between the imine NH and oxime N atoms. The oxime group and the amide C=O bond are anti to each other. In the crystal, molecules are connected by O—H⋯O hydrogen bonds into supramolecular zigzag chains along the c axis
The architecture of it-environment for vocational education and training specialists in geoinformatics
© SGEM2017. All Rights Reserved. In this paper the approach to Information Educational Environment (IEE) creation is proposed. IEE is a complicated system that consists of a lot of hardware and software tools. Open architecture of the IEE provides integration of various electronic educational resources (virtual laboratories, virtual departments, electronic scientific-educational complexes). A variety of different hardware and software tools allow to create a variety of educational routes. In this paper we highlighted the main aspects about IEE creation. The composition and structure of the IEE is discussed. Experience of using the system is presented. The description of the curriculums, practical works, and laboratory tasks is given. The main component of the system is Electronic Scientific-Educational Complex “Geoinformation Technologies and Systems”. The Complex provides comprehensive support for research and educational activities in the field of Geoinformatics – from training sessions with the use of modern educational technologies to independent research work of students
Особливості взаємодії 3-(2-амінофеніл)-6-R-1,2,4-триазин-5(2H)-онів та циклічних ангідридів несиметричних дикарбонових кислот
The peculiarities of the reaction between 3-(2-aminophenyl)-6-R-1,2,4-triazin-5(2H)-ones and cyclic anhydrides of non-symmetric (2-methylsuccinic, 2-phenylsuccinic and camphoric) acids have been described in the present article. The influence of electronic and steric effects of substituents in the anhydride molecule on cyclisation processes has been discussed. The results have shown that the interaction of 3-(2-aminophenyl)-6-R-1,2,4-triazin- 5(2H)-ones mentioned above with 2-methylsuccinic and 2-phenylsuccinic acid anhydrides proceeded non-selectively and yielded the mixtures of 2-R1-3-(2-oxo-3-R-2H-[1,2,4]triazino[2,3-c]quinazoline-6-yl)propanoic acids and 1-(2-(5-oxo-6-R-2,5-dihydro-1,2,4-triazin-3-yl)phenyl)-3-R1-pyrrolidine-2,5-diones. It has been found that low regioselectivity of the acylation process may be explained by insignificant electronic effects of substituents (of the methyl and phenyl fragment) in position 2 of the anhydride molecule on the electrophilic reaction centre. It has been also determined that the reaction between 3-(2-aminophenyl)-6-R-1,2,4-triazin-5(2H)-ones and camphoric anhydride proceeds regioselectively and yielded 1,2,2-trimethyl-3-(3-R-2-oxo-2H-[1,2,4]triazino[2,3-c]quinazolin- 6-yl)cyclopentan-1-carboxylic acids. Regioselectivity of the interaction mentioned above may be explained by the steric effect of the methyl group. Identity of compounds has been proven by LC-MS, the structure has been determined via a set of characteristic signals in 1H NMR, 13C NMR spectra and position of cross peaks in the correlation HSQC-experiment. Mass spectra of the compounds synthesized have been also studied, the principal directions of the molecule fragmentation have been described. The structure of 1,2,2-trimethyl-3-(3-methyl- 2-oxo-2H-[1,2,4]triazino[2,3-c]quinazolin-6-yl)cyclopentane-1-carboxylic acid has been proven by X-ray analysis.Описаны особенности реакции между 3-(2-аминофенил)-6-R-1,2,4-триазин-5(2H)-онами и ангидридами несимметричных дикарбоновых кислот (2-метилянтарной, 2-фенилянтарной и камфорной) кислот. Проведено обсуждение влияния электронных и стерических эффектов заместителей на процессы цик- лизации. Результаты показали, что взаимодействие приведенных выше 3-(2-аминофенил)-6-R-1,2,4- триазин-5(2H)-онов с ангидридами 2-метилянтарной и 2-фенилянтарной кислот протекало не региоселективно с образованием смесей 2-R 1-3-(2-оксо-3-R-2H-[1,2,4]триазино[2,3-c]хиназолин-6-ил)про- пановых кислот и 1-(2-(5-оксо-6-R-2,5-дигидро-1,2,4триазин-3-ил)фенил)-3-R1-пиролидин-2,5-дионов. По- казано, что низкая региоселективность процесса ацилирования может быть объяснена незначительными электронными эффектами заместителей (метильного и фенильного фрагмента) в положении 2 молекулы ангидрида на электрофильный реакционный центр. Также установлено, что реакция между 3-(2-аминофенил)-6-R-1,2,4-триазин-5(2H)-онами и ангидридом камфорной кислоты протекает регио- селективно и приводит к образованию 1,2,2-триметил-3-(3-R-2-оксо-2H-[1,2,4]триазино[2,3-c]хиназолин- 6-ил)циклопентан-1-карбоновых кислот. Селективность реакции в данном случае может быть объяснена стерическим эффектом метильной группы. Индивидуальность соединений подтверждена ме- тодами LC-MS, структуру установлено по положению характеристических сигналов в 1H ЯМР и 13С ЯМР-спектрах и по положению кросс-пиков в корреляционном HSQC-эксперименте. Также были иссле- дованы масс-спектры синтезированных соединений и описаны основные направления фрагментации молекулярных ионов. Структуру 1,2,2-триметил-3-(3-метил-2-оксо-2H-[1,2,4]триазино[2,3-c]хиназолин- 6-ил)циклопентан-1-карбоновой кислоты было доказано с помощью рентгеноструктурного анализа.Описані особливості реакції між 3-(2-амінофеніл)-6-R-1,2,4-триазин-5(2H)-онами з ангідридами несимет- ричних дикарбонових кислот (2-метилбурштинової, 2-фенілбурштинової та камфорної) кислот. Обго- ворено вплив електронних та стеричних ефектів замісника у молекулі ангідриду на процеси циклізації. Результати показали, що взаємодія наведених вище 3-(2-амінофеніл)-6-R-1,2,4-триазин-5(2H)-онів з ангідридами 2-метилбурштинової та 2-фенілбурштинової кислот перебігала нерегіоселективно з утворенням суміші 2-R1-3-(2-оксо-3-R-2H-[1,2,4]триазино[2,3-c]хіназолін-6-іл)пропанових кислот та 1-(2- (5-оксо-6-R-2,5-дигідро-1,2,4триазин-3-іл)феніл)-3-R1-піролідин-2,5-діонів. Показано, що низька регіосе- лективність процесу ацилювання може бути пояснена незначними електронними ефектами замісників (метального та фенільного фрагменту) у положенні 2 молекули ангідриду на електрофільний реакційний центр. Також встановлено, що реакція між 3-(2-амінофеніл)-6-R-1,2,4-триазин-5(2H)-онами та ангідридом камфорної кислоти перебігає регіоселективно та приводить до утворення 1,2,2-триметил-3-(3- R-2-оксо-2H-[1,2,4]триазино[2,3-c]хіназолін-6-іл)циклопентан-1-карбонових кислот. Селективність за- значеної вище реакції може бути пояснена стеричними ефектами метальної групи. Індивідуальність сполук підтверджена методом LC-MS, структуру встановлено за положенням характеристичних сигналів у 1H ЯМР та 13С ЯМР-спектрах та за положенням крос-піків у кореляційному HSQC-експерименті. Також були досліджені мас-спектри синтезованих сполук та описані основні напрямки фрагментації молекулярних іонів. Структуру 1,2,2-триметил-3-(3-метил-2-оксо-2H-[1,2,4]триазино[2,3-c]хіназолін-6-іл) циклопентан-1-карбонової кислоти було доведено за допомогою рентгеноструктурного дослідження
High-Temperature Lightweight Ceramics with Nano-sized Ferrites for EMI Shielding: Synthesis, Characterization, and Potential Applications
The present study focuses on the synthesis and characterisation of a lightweight ceramic material with electromagnetic interference (EMI) shielding properties, achieved using mullite containing micrometre-sized hollow spheres (cenospheres) and CoFe2O4 nanoparticles. This research explores compositions with varying CoFe2O4 contents ranging from 0 up to 20 wt.%. Conventional sintering in an air atmosphere is carried out at a temperature between 1100 and 1300 °C. The addition of ferrite nanoparticles was found to enhance the process of sintering cenospheres, resulting in improved material density and mechanical properties. Furthermore, this study reveals a direct correlation between the concentration of ferrite nanoparticles and the electromagnetic properties of the material. By increasing the concentration of ferrite nanoparticles, the electromagnetic shielding effect of the material (saturation magnetisation (Ms ) and remanent magnetisation (Mr)) was observed to strengthen. These findings provide valuable insights into designing and developing lightweight ceramic materials with enhanced electromagnetic shielding capabilities. The synthe-sized ceramic material holds promise for various applications that require effective electromagnetic shielding, such as in the electronics, telecommunications, and aerospace industries
The Angular Momentum Operator in the Dirac Equation
The Dirac equation in spherically symmetric fields is separated in two
different tetrad frames. One is the standard cartesian (fixed) frame and the
second one is the diagonal (rotating) frame. After separating variables in the
Dirac equation in spherical coordinates, and solving the corresponding
eingenvalues equations associated with the angular operators, we obtain that
the spinor solution in the rotating frame can be expressed in terms of Jacobi
polynomials, and it is related to the standard spherical harmonics, which are
the basis solution of the angular momentum in the Cartesian tetrad, by a
similarity transformation.Comment: 13 pages,CPT-94/P.3027,late
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