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排序方式: 共有117条查询结果,搜索用时 31 毫秒
1.
Ye Gao YIN* Willis FORSLING Dan BOSTR諱 Oleg ANTZUTKIN Mats LINDBERG Alexander IVANOV Department of Chemistry Faculty of Science The University of Shantou Shantou Division of Inorganic Chemistry Department of Chemical Metallurgical Engineering Lule?University of Technology. Lule?se- Sweden Department of Chemistry Ume University Ume se-- Sweden 《中国化学快报》2003,14(2)
Owing to the particular affinity toward metal ion and changeable dentation, dialkyldithiophosphates are commonly used ligands in preparation of the transition metal complexes with variable structures1. For instances relevant to this work, the IIB metal complexes defined crystallographically so far have provided the examples as follows2-12 (Scheme 1). Scheme 1 The frameworks of IIB metal complexes of dialkyldithiophosphate MMMMMMMMMM a b c d … 相似文献
2.
Anastacia A. Layeva Galina N. Lipunova Valerii N. Charushin 《Journal of fluorine chemistry》2007,128(7):748-754
A new approach for the synthesis of fluorinated 1H-quinazolin-4-ones and 4-substituted quinazolines has been developed. 6-Fluoro-1H-quinazolin-4-ones were obtained by intramolecular cyclization of fluorine-containing S-ethyl N-benzoylisothioureas. Nucleophilic substitution reactions at positions 2 and 7, as well as alkylation at 1-position of quinazolinones were investigated. In addition, the synthesis of fluorine-containing 4-aminoquinazolines was carried out. 相似文献
3.
Alexander M. Schneider Luyao Lu Eric F. Manley Tianyue Zheng Valerii Sharapov Tao Xu Tobin J. Marks Lin X. Chen Luping Yu 《Chemical science》2015,6(8):4860-4866
We report the properties of a new series of wide band gap photovoltaic polymers based on the N-alkyl 2-pyridone dithiophene (PDT) unit. These polymers are effective bulk heterojunction solar cell materials when blended with phenyl-C71-butyric acid methyl ester (PC71BM). They achieve power conversion efficiencies (up to 5.33%) high for polymers having such large bandgaps, ca. 2.0 eV (optical) and 2.5 eV (electrochemical). Grazing incidence wide-angle X-ray scattering (GIWAXS) reveals strong correlations between π–π stacking distance and regularity, polymer backbone planarity, optical absorption maximum energy, and photovoltaic efficiency. 相似文献
4.
In this study, new biodegradable and biocompatible amphiphilic polymers were obtained by modifying the peripheral hydroxyl groups of branched polyethers and polyesters with organosilicon substituents. The structures of the synthesized polymers were confirmed by NMR and GPC. Organosilicon moieties of the polymers were formed by silatranes and trimethylsilyl blocks and displayed hydrophilic and hydrophobic properties, respectively. The effect of the ratio of hydrophilic to hydrophobic organosilicon structures on the surface activity and biological activity of macromolecules was studied, together with the effect on these activities of the macromolecules’ molecular weight and chemical structure. In particular, the critical micelle concentrations were determined, the effect of the structure of the polymers on their wetting with aqueous solutions on glass and parafilm was described, and the aggregation stability of emulsions was studied. Finally, the effect of the polymer structures on their antifungal activity and seed germination stimulation was examined. 相似文献
5.
Valerii F. Traven Dmitriy A. Cheptsov Zarina Z. Mamirgova Natalya P. Solovjova Vyacheslav M. Martynenko Sergei M. Dolotov Michail M. Krayushkin Ivan V. Ivanov 《Photochemistry and photobiology》2020,96(4):798-804
Photophysical characteristics of new 3-(1-acyl-5-aryl-3-pyrazolinyl)coumarins have been measured. These coumarin derivatives are found to be effective fluorophores and show high values of quantum yields of fluorescence both in nonpolar and in polar solvents. The 3-(1-acyl-5-aryl-3-pyrazolinyl)coumarins turned to be photosensitive compounds and undergo photolysis under irradiation in the range of 310–465 nm. Photolysis is suggested to include retro-cyclization and retro-condensation steps. The process is accompanied by a sharp drop of fluorescence that can be of interest for the creation of new media in optical recording of information. 相似文献
6.
Boris N. Kozlov Ivan I. Pilyugin Valerii G. Shchebelin Alexander V. Bulgakov Alexander P. Mayorov Mikhail R. Predtechenskii 《Mikrochimica acta》1995,120(1-4):111-119
A time-of-flight mass spectrometer with electron impact ionization facility was used in investigations of the laser plume structure. Densities and velocity distributions of positively charged and neutral species were measured 12 cm downstream of the target. Velocities of particles in a plume were measured by the retarding potential method. The combination of a skimmer and declining electric field was used to suppress the influence of charged particles during the measurement of the neutral component parameters. In the case of YBaCuO ceramic laser ablation, a strong variation of the laser-induced plume composition was observed from its head to its tail. It seems to be accounted for by the difference of the starting (phase transition) temperatures of various layers of a plume. Ions detected mainly in the head of a plume were followed by atoms, molecules and clusters in inverse succession to their appearance in the plume under the light intensity increase. The characteristic of the number density dependence upon the laser spot diameter make it clear that most of the molecules BaO and YO are the direct product of ablation. In contrast, the detected clusters with masses up to 2000 amu are the product of condensation in the expanding plume under the conditions of the experiments. 相似文献
7.
For plus-operators in a Banach indefinite space, we consider a linear-fractional relation. The classes of operators with the
empty domain of definition for such a relation are described. The sufficient (and necessary, in some meaning) conditions for
the chain rule to be valid are given. 相似文献
8.
Valerii P. Aksenov Igor V. Izmailov Feodor Yu. Kanev Boris N. Poizner 《Optics Communications》2012,285(6):905-928
The principle of determining the topological charge of an optical vortex is suggested based on measuring the light field intensity and designing the corresponding detector. A mathematical model of the performance of the detector of topological vortex charge is presented. Results of numerical experiments imitating the vortex recognition in the presence of turbulence or (amplitude or phase) noise in registered radiation as well as of the displacement of the optical beam source and detector axes are presented. Principles are formulated of designing the position finder for an optical vortex (that is, the detector of vortex coordinates) that allows us to consider its realization in the form of mathematical and numerical model. Conditions of reliable operation of the vortex detector and singular optical communication line constructed on its basis are estimated. Dependencies of the probability of error in data transfer on the turbulence intensity, photodetector noise amplitude, and displacement of the optical axes are investigated for different coding algorithms (absolute and differential with fixed or adaptive threshold). The data of modeling confirm the results of analytical calculations. 相似文献
9.
10.
LOSEV V F PANCHENKO Yu N DUDAREV V V IVANOV N G KONOVALOV I N PAVLINSKY A V PUCHIKIN A V 《中国光学与应用光学文摘》2011,(1)
研究了脉冲宽度为25~40 ns的放电脉冲XeCl准分子激光器的工作参数。结果显示,激光器产生的脉冲能量为0.2~0.7 J,重复频率为100 Hz,表明在泵浦功率为2.8~3.3 MW/cm3时,激光器实现了2.6%的激光效率和3.8%的本征效率。 相似文献