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排序方式: 共有218条查询结果,搜索用时 15 毫秒
1.
V. M. Ogenko A. V. Fesenko N. D. Konovalova V. I. Stepanenko 《Reaction Kinetics and Catalysis Letters》1993,50(1-2):169-173
It has been established that CO oxidation with excess O2 on Ni/Al2O3 forms an inhomogeneous NiO contact surface that smoothes critical effects in the sharp reactivity change. 相似文献
2.
S. A. Goncharov A. M. Mukhamedzhanov E. A. Romanovskii G. E. Valiev I. R. Gulamov Yu. I. Denisov T. Iskhakov A. Karakhodzhaev G. K. Nie R. Yarmuchamedov V. A. Stepanenko V. Kroha 《Czechoslovak Journal of Physics》1988,38(1):12-18
The differential cross sections of tritons from the (d, t) reaction on9Be,10B and13C targets have been measured in the angular range of 5°
LAB110° with relatively small errors, 5%. The experimental data were analysed in terms of the standard DWBA using both zero-range and exact finite-range approaches. 相似文献
3.
Kulikov M. A. Vorob'ev Yu. G. Berezina G. R. Stepanenko V. A. 《Russian Journal of General Chemistry》2004,74(6):954-956
Novel symmetrical macroheterocyclic compounds were prepared by the reactions of 2,3-dicyanopyridine and 2,3-dicyanopyraine with 2,5-diamino-1,3,4-thiadiazole in butanol in the presence of sodium butylate. Physicochemical properties and biological activity of the products were studied. 相似文献
4.
The lipid compositions of the coats and kernels of the seeds ofNepeta pannonica andLavandula vera have been studied. It has been established that the lipids of the seed coats of the two species of plants differ substantially
in their composition. The lipids of the kernels ofNepeta have been found to contain free fatty acids with chain lengths of from C20 to C35. Ursolic acid and its acetate have been isolated from extracts of the seed coats ofLavandula, and dimethyladipic acid from the seed oil of this species.
Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh
Soedinenii, No. 5, pp. 614–620, September–October, 1980. 相似文献
5.
Dr. Vladimir Stepanenko Dr. Xue‐Qing Li Jana Gershberg Prof. Dr. Frank Würthner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(13):4176-4183
The self‐assembly behavior of an achiral perylene bisimide (PBI) organogelator that bears two 3,4,5‐tridodecyloxybenzoylaminoethyl substituents at the imide positions has been investigated in chiral solvents (R)‐ and (S)‐limonene in great detail by circular dichroism (CD) spectroscopy and atomic force microscopy (AFM). CD spectroscopic studies on dilute solutions revealed a preferential population of one‐handed helical assemblies in chiral solvent with an enantiomeric excess close to 100 %, whereas AFM images of more than 100 nanofibers of the organogel obtained from more concentrated solutions were found to consist of both handed helices with an enantiomeric excess of only 20 %. This discrepancy is attributed to the fast gelation process at high dye concentration that evidently proceeds through non‐equilibrated nuclei in a kinetic rather than thermodynamic self‐assembly process. Under these conditions the chiral induction from the homochiral solvent may not be adequate in effectively populating only one‐handed helices. 相似文献
6.
Markus Hecht Dr. Pawaret Leowanawat Tabea Gerlach Dr. Vladimir Stepanenko Dr. Matthias Stolte Prof. Dr. Matthias Lehmann Prof. Dr. Frank Würthner 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17232-17238
A new perylene bisimide (PBI), with a fluorescence quantum yield up to unity, self-assembles into two polymorphic supramolecular polymers. This PBI bears four solubilizing acyloxy substituents at the bay positions and is unsubstituted at the imide position, thereby allowing hydrogen-bond-directed self-assembly in nonpolar solvents. The formation of the polymorphs is controlled by the cooling rate of hot monomer solutions. They show distinctive absorption profiles and morphologies and can be isolated in different polymorphic liquid-crystalline states. The interchromophoric arrangement causing the spectral features was elucidated, revealing the formation of columnar and lamellar phases, which are formed by either homo- or heterochiral self-assembly, respectively, of the atropoenantiomeric PBIs. Kinetic studies reveal a narcissistic self-sorting process upon fast cooling, and that the transformation into the heterochiral (racemic) sheetlike self-assemblies proceeds by dissociation via the monomeric state. 相似文献
7.
We demonstrate spatial interference fringe pattern by simultaneous one- and three-photon absorption of UV and near-IR femtosecond pulses in thin film organic solid at room temperature. We use organic dendrimers that are specially designed to have strong fluorescence and very large three-photon absorption cross-section. High fringe visibility allows the quantum interference to be observed by eye. 相似文献
8.
A. N. Vasil'ev S. É. Derkachev N. A. Kibel' A. S. Stepanenko 《Theoretical and Mathematical Physics》1992,92(3):1047-1054
It is shown that for all multiplicatively renormalizable fermionic models without derivativs in the interaction, in particular, for the Gross—Neveu model, conformal invariance of the Green's functions of the fields in the critical regime (massless model at fixed renormalization-group point) automatically follows from the scale invariance for arbitrary space dimension.St Petersburg State University. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 92, No. 3, pp. 486–497, September, 1992. 相似文献
9.
JETP Letters - Analytical expressions have been obtained for the resonance component of the interlayer conductivity of quasi-two-dimensional conductors in an inclined magnetic field in the presence... 相似文献
10.
Zhu Wu Jrn Nitsch Julia Schuster Alexandra Friedrich Katharina Edkins Marcel Loebnitz Fabian Dinkelbach Vladimir Stepanenko Frank Würthner Christel M. Marian Lei Ji Todd B. Marder 《Angewandte Chemie (International ed. in English)》2020,59(39):17137-17144
Achieving highly efficient phosphorescence in purely organic luminophors at room temperature remains a major challenge due to slow intersystem crossing (ISC) rates in combination with effective non‐radiative processes in those systems. Most room temperature phosphorescent (RTP) organic materials have O‐ or N‐lone pairs leading to low lying (n, π*) and (π, π*) excited states which accelerate kisc through El‐Sayed's rule. Herein, we report the first persistent RTP with lifetimes up to 0.5 s from simple triarylboranes which have no lone pairs. RTP is only observed in the crystalline state and in highly doped PMMA films which are indicative of aggregation induced emission (AIE). Detailed crystal structure analysis suggested that intermolecular interactions are important for efficient RTP. Furthermore, photophysical studies of the isolated molecules in a frozen glass, in combination with DFT/MRCI calculations, show that (σ, B p)→(π, B p) transitions accelerate the ISC process. This work provides a new approach for the design of RTP materials without (n, π*) transitions. 相似文献