排序方式: 共有33条查询结果,搜索用时 15 毫秒
1.
V.Yu. Baranovsky L.A. Kazarin A.A. Litmanovich I.M. Papisov 《European Polymer Journal》1984,20(2):191-194
Polycomplex formation between poly(methacrylic acid) and polyacrylamide in aqueous solutions has been studied by means of viscometry, potentionetry and elemental analysis. Stoichiometry of the polycomplex was found to be 1:1 with respect to unit-moles. I.R.-spectroscopic data give evidence of the co-existence of ladder-like regions and loops in the polycomplexes formed by poly(methacrylic acid) with polyacrylamide and poly(ethylene glycol). The reactivities of the same functional groups in ladder-like regions and loops are different. This difference has been shown taking as an example thermochemical reactions in the above polycomplexes. Dehydrocyclization in the poly(methacrylic acid) chain was found to occur in the loops of both polycomplexes. This intramolecular reaction in the polycomplex of poly(methacrylic acid) with polyacrylamide is followed by intermolecular formation of imide bonds in ladder-like regions. 相似文献
2.
Pavel F. Vlad Alexandru G. Ciocarlan Mihai N. Coltsa Alexandr V. Baranovsky Natalya B. Khripach 《合成通讯》2013,43(22):3960-3972
This article describes a new efficient synthesis of drim-7,9(11)-diene and its hydroxylated derivates from drim-8-en-7-one. Reduction of this ketone with NaBO4 in the presence of CeCl3 · 7H2O afforded regio- and stereoselectively drim-8-en-7β-ol in a high yield. Its dehydration with H2SO4 under mild conditions led to drim-7,9(11)-diene. Noncatalytic oxidation of drim-7,9(11)-diene with OsO4 and the catalytic oxidation with the pair OsO4–NMO gave, in a high yield, depending on conditions, driman-7β,8β,9α,11-tetraol or its mixture with drim-7-en-9α,11-diol and drim-9(11)-en-7α,8α-diol. Under optimal conditions the total yield of these diols reached 89%. The separate, noncatalytic oxidation of drim-7-en-9α,11-diol and of drim-9(11)-en-7α,8α-diol with OsO4 afforded driman-7α,8α,9α,11-tetraol. 相似文献
3.
V. Yu. Baranovsky S. Shenkov 《Journal of polymer science. Part A, Polymer chemistry》1996,34(2):163-167
A competitive complex forming reaction between a number of monosubstituted poly(ethylene glycol)s (PEG*) containing a hydrophobic group of differing chemical nature and nonsubstituted PEG of various molecular weights with poly(methacrylic acid) (PMAA) was studied. A UV spectroscopy method was used. During the transfer of the hydrophobic chromophoric group from the aqueous medium into the hydrophobic domains of the polycomplex (PMAA.PEG*), a bathochromic effect was observed. The introduction of a hydrophobic group into the PEG chain leads to stabilization of the polycomplex (PMAA.PEG) that is formally the same as growing the chain length of PEG. The polymerization degree of PEG having the same competitive power as PEG* can be used as the peculiar scale of the complex forming ability of PEG* in the complexation with PMAA. © 1996 John Wiley & Sons, Inc. 相似文献
4.
T.S. Khlebnicova V.G. Isakova A.V. Baranovsky E.V. Borisov F.A. Lakhvich 《Journal of fluorine chemistry》2006,127(12):1564-1569
A one-pot synthesis of 2-perfluoroalkanoylcyclohexane-1,3-diones via C-acylation of cyclohexane-1,3-diones with N-perfluoroacylimidazole as an acylating agent is reported. A reaction was examined with isolated N-trifluoroacetylimidazole and with N-perfluoroacylimidazoles generated in situ from perfluorocarboxylic acid anhydrides or perfluorocarboxylic acids. 相似文献
5.
6.
Let X and Y be two smooth Deligne-Mumford stacks and consider a pair of functions f: X → $
\mathbb{A}^1
$
\mathbb{A}^1
, g:Y → $
\mathbb{A}^1
$
\mathbb{A}^1
. Assuming that there exists a complex of sheaves on X × $
\mathbb{A}^1
$
\mathbb{A}^1
Y which induces an equivalence of D
b
(X) and D
b
(Y), we show that there is also an equivalence of the singular derived categories of the fibers f
−1(0) and g
−1(0). We apply this statement in the setting of McKay correspondence, and generalize a theorem of Orlov on the derived category
of a Calabi-Yau hypersurface in a weighted projective space, to products of Calabi-Yau hypersurfaces in simplicial toric varieties
with nef anticanonical class. 相似文献
7.
8.
Vladimir Baranovsky 《Selecta Mathematica, New Series》2010,16(2):297-313
Let X be a proper scheme over a field k which satisfies Serre’s condition S 2 and G a reductive group over k. We prove that the functor of principal G-bundles, defined away from a non-fixed closed subset in X of codimension at least 3, is an algebraic stack in the sense of Artin. 相似文献
9.
10.
Wasserman AM Kasaikin VA Zakharova YA Aliev II Baranovsky VY Doseva V Yasina LL 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2002,58(6):1241-1255
Molecular dynamics and organization of the micellar phase of complexes of linear polyelectrolytes with ionogenic and non-ionogenic surfactants was studied by the ESR spin probe method. Complexes of polyacrylic acid (PAA) and sodium polystyrenesulfonate (PSS) with alkyltrimethylammonium bromides (ATAB), as well as complexes of poly-N,N'-dimethyldiallylammonium chloride (PDACL) with sodium dodecylsulfate (SDS) were studied. The micellar phase of such complexes is highly organized molecular system, molecular ordering of which near the polymeric chain is much higher than in the 'center' of the micelle, it depends on the polymer-detergent interaction, flexibility of polymeric chain and length of carbonic part of the detergent molecule. Complexes of polymethacrylic acid (PMAA) with non-ionic detergent (dodecyl-substituted polyethyleneglycol), show that the local mobility of surfactant in such complexes is significantly lower than in 'free' micelles and depends on the number of micellar particles participating in formation of complexes. 相似文献