排序方式: 共有83条查询结果,搜索用时 738 毫秒
31.
Anastasia V. Egorova Nikolai B. Viktorov Galina L. Starova Nataly I. Svintsitskaya Aleksandr V. Garabadziu Albina V. Dogadina 《Tetrahedron letters》2017,58(30):2997-3001
The boron trifluoride diethyl etherate catalyzed intramolecular cyclization of diethyl 2-(dialkoxyphosphorylethynyl)-2-arylaminomalonates afforded a series of novel 3-phosphonylated indoles, diethyl 2-[3-(dialkoxyphosphoryl)-1H-indol-2-yl]propanedioates. Decarboxylation of the latter compounds resulted in the formation of ethyl 2-[3-(dialkoxyphosphoryl)-1H-indol-2-yl]acetates. 相似文献
32.
G.L. Brekhovskikh V.V. Zverev N.Y. Okladnikov A.I. Sokolovskaia 《Optics Communications》1985,53(1):59-63
The energy dependence and the total saturation of the SRS and SBS are investigated in the nanosecond range at different geometries of the illuminated volume. The theoretical explanation of the experimental results for SRS is given, the change of the vibrational level population being taken into account. The solution of the quasi-stationary equations for SRS if shown to have the form of a solitary wave. The results of the work permit to govern the amplitude-phase distribution of the complex light fields at the stimulated scatterings. 相似文献
33.
Vytautas Getautis Giedre Sinkeviciute Albina Stanisauskaite 《Monatshefte für Chemie / Chemical Monthly》2007,45(10):477-480
A synthesis of 1,2-diphenylpyrazolidin-4-ol via direct heterocyclization of 1,2-diphenylhydrazine with 1-chloro-2,3-epoxypropane, its O-epoxypropyl-, O-ethyl-, and O-benzylderivatives are described. Novel hydrazone derivatives with pyrazolidine units were also synthesized. The compounds
were characterized by spectroscopic methods as well as elemental analyses. 相似文献
34.
Ella Kh. Kazakova Albina U. Ziganshina Liya A. Muslinkina Julija E. Morozova Nelly A. Makarova Asija R. Mustafina Wolf D. Habicher 《Journal of inclusion phenomena and macrocyclic chemistry》2002,43(1-2):65-69
The flexible bowl-type water-soluble molecule1, consisting of a resorcinol core and fourconvergent tetrasulfonatomethylene groups, existingas a tetraanion in neutral water solution, was studiedas the host molecule for recognition of-aminoacids. Out of 12 examined guestmolecules only those possessing aromatic hydrophobicmoieties or a long hydrophobic chain with a second ionogenic groupform inclusion complexes with 1. The complex formationwas considered with the help of both 1H NMRand pH-metric titration in a broad range of pH.The role of host and guest geometric complementarity aswell as additional – and hydrophobic interactionsis discussed. The lack of these interactions inaqueous media provides domination of the guestsolvation by water over the 1 : 1 complexformation with 1. 相似文献
35.
Vytautas Getautis Albina Stanisauskaite Rimgaile Degutyte Jolanta Stumbraite 《Monatshefte für Chemie / Chemical Monthly》2007,138(12):1293-1296
Summary. Intramolecular cyclization of N,N′-di(3-chloro-2-hydroxy)propyl-N,N′-diphenylbenzidine occurs to give bis-1,2,3,4-tetrahydroquinoline derivative 1,1′-diphenyl-1,2,3,4,1′,2′,3′,4′-octahydro-6,6′-biquinolinyl-3,3′-diol. 相似文献
36.
Albina Y. Borisevich 《Journal of solid state chemistry》2003,170(1):198-201
A new 1:2 ordered perovskite La(Li1/3Ti2/3)O3 has been synthesized via solid-state techniques. At temperature >1185°C, Li and Ti are randomly distributed on the B-sites and the X-ray powder patterns can be indexed in a tilted (b−b−c+) Pbnm orthorhombic cell (a=ac√2=5.545 Å, b=ac√2=5.561 Å, c=2ac=7.835 Å). However, for T?1175°C, a 1:2 layered ordering of Li and Ti along 〈111〉c yields a structure with a P21/c monoclinic cell with a=ac√6=9.604 Å, b=ac√2=5.552 Å, c=ac3√2=16.661 Å, β=125.12°. While this type of order is well known in the A2+(B2+1/3B5+2/3)O3 family of niobates and tantalates, La(Li1/3Ti2/3)O3 is the first example of a titanate perovskite with a 1:2 ordering of cations on the B-sites. 相似文献
37.
Bormashenko E Pogreb R Stein T Whyman G Erlich M Musin A Machavariani V Aurbach D 《Physical chemistry chemical physics : PCCP》2008,10(27):4056-4061
Wetting transitions were studied with vertically-vibrated drops on various artificial and natural rough substrates. Alternative pathways of wetting transitions were observed. The model of wetting transition is presented. Multiple minima of the Gibbs free energy of a drop deposited on a rough surface explain alternative pathways of wetting transitions. We demonstrate that a wetting transition occurs when the constant force resulting from vibrations, Laplace and hydrostatic pressure acts on the triple line. It is shown that the final wetting states are mainly the Cassie impregnating wetting state with water penetrating the pores in the outer vicinity of the droplet or the Wenzel state with water inside the pores under the droplet whereas the substrate ahead the drop is dry. 相似文献
38.
39.
Edward Bormashenko Dr. Yelena Bormashenko Albina Musin Zahava Barkay Dr. 《Chemphyschem》2009,10(4):654-656
Little hovercrafts: The mechanisms of floating and sliding of liquid marbles (see picture) are elucidated. It is demonstrated that floating and sliding liquid marbles are separated from their supporting media by an air layer, resembling Leidenfrost drops. An ESEM study of the marble surface shows a rugged surface facilitating the trapping of air.
40.
Trofimov BA Ivanov AV Ushakov IA Schmidt EY Sobenina LN Vasil'tsov AM Mikhaleva AI 《Dalton transactions (Cambridge, England : 2003)》2012,41(18):5512-5516
N-Vinylpyrroles and -indoles bearing electron-withdrawing substituents at the pyrrole ring are mercurated, with 1 equivalent of Hg(OAc)(2) in dry MeCN (20-80 °C), regioselectively at the vinyl group (yields are almost quantitative), while their congeners without electron-withdrawing functions are mercurated both at the N-vinyl group and the pyrrole ring. 相似文献