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1.
Aggregated aromatic molecule--cyclodextrin-precipitant complexes exhibit long-lived phosphorescence at room temperature in water after the chemical binding of oxygen. The temperature dependences of the phosphorescence lifetimes of naphthalene-h8, naphthalene-de, and phenanthrene in the aggregates were measured. For example, the phosphorescence lifetimes of naphthalene-d8 aggregated with -cyclodextrin and cyclohexane are equal to 25.1, 17.6, and 6.8 s at 77, 276, and 347 K, respectively, and that of phenanthrene aggregated with isooctane and -cyclodextrin are 3.24, 3.06, and 1.26 s at 268, 274, and 335 K, respectively. The temperature dependences of the phosphorescence lifetimes at room temperature are determined by the rate constants of the radiative and nonradiative transitions from the triplet state of an aromatic molecule.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2225–2228, September, 1996. 相似文献
2.
The triplet-triplet absorption spectra of a number of aromatic molecules were shown to be broadened in low temperature matrices formed by aromatic solvents (toluene, 4-isopropylbiphenyl) as compared with those in aliphatic solvents (ethanol, methylcyclohexane, triethylamine). The effect is exponentially dependent on the energy of the upper triplet state of the solute molecule. The phenomenon is discussed in terms of a strong exchange-resonance interaction between the triplet states of solute and solvent. 相似文献
3.
The energy transfer from the upper triplet states of diphenylamine, naphthalene and triphenylene to toluene and hexene-1 is studed. Two mechanisms of dissipation transferred energy in solvents are discussed. 相似文献
4.
A. A. Gerko 《Journal of Mathematical Sciences》2007,142(4):2205-2232
For finite modules over a local ring and complexes with finitely generated homology, we consider several homological invariants
sharing some basic properties with projective dimension.
In the second section, we introduce the notion of a semidualizing complex, which is a generalization of both a dualizing complex and a suitable module. Our goal is to establish some common properties of such complexes and the homological dimension with respect to them.
Basic properties are investigated in Sec. 2.1. In Sec. 2.2, we study the structure of the set of semidualizing complexes over
a local ring, which is closely related to the conjecture of Avramov-Foxby on the transitivity of the G-dimension. In particular,
we prove that, for a pair of semidualizing complexes X
1 and X
2 such that G
X2, we have X
2 ≃ X
1 ⊗
R
L
RHom
R
(X
1, X
2). Specializing to the case of semidualizing modules over Artinian rings, we obtain a number of quantitative results for the
rings possessing a configuration of semidualizing modules of special form. For the rings with m
3=0, this condition reduces to the existence of a nontrivial semidualizing module, and we prove a number of structural results
in this case.
In the third section, we consider the class of modules that contains the modules of finite CI-dimension and enjoys some nice
additional properties, in particular, good behavior in short exact sequences.
In the fourth section, we introduce a new homological invariant, CM-dimension, which provides a characterization for Cohen-Macaulay
rings in precisely the same way as projective dimension does for regular rings, CI-dimension for locally complete intersections,
and G-dimension for Gorenstein rings.
__________
Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 30, Algebra,
2005. 相似文献
5.
A. I. Gerko 《Mathematical Notes》2000,67(6):707-717
In the paper methods from the theory of extensions of dynamical systems are used to studyβ-differential equations whose solutions possess the uniqueness property and depend continuously on the initial data and on
the right-hand side of the equation. The Zhikov-Bronshtein theorems concerning asymptotically almost periodic solutions of
ordinary differential equations are extended toβ-differential equations (in particular, to total differential equations). Along with asymptotic almost periodicity, we also
consider asymptotic recurrence, weak asymptotic distality, and asymptotic distality. To the equations we associate dynamical
systems generated by the space of the right-hand sides and the spaces of the solutions and of the initial data of solutions
of the equation. Generally, the phase semigroups of the dynamical systems are not locally compact.
Translated fromMatermaticheskie Zametki, Vol. 67, No. 6, pp. 837–851, June, 2000. 相似文献
6.
7.
We extend (with some generalizations) Bronshtein's theorems about the disjointness of F-, PE-, V-extensions of minimal topological transformation groups. 相似文献
8.
Two-Dimensional Coordination Polymer {[Zn(Pht)(4.4′-Bipy)(H2O)2] · 2H2O} n : Synthesis and Structure
Simonov Yu. A. Baca S. G. Filippova I. G. Gdaniec M. Gerko O. A. Gerbeleu N. V. 《Russian Journal of Coordination Chemistry》2004,30(10):727-732
The coordination polymer {[Zn(Pht)(4,4-Bipy)(H2O)2] · 2H2O}
n
(where Pht is a doubly deprotonated phthalic acid residue and 4,4-Bipy is 4,4-bipyridine) was synthesized and studied by X-ray diffraction. It was shown that both ligands perform a bridging function and unite the Zn atoms into a two-dimensional network with a periodicity of 11.302(2) Å (with 4,4-Bipy as the bridge) or 7.627(2) Å (with Pht as the bridge). The coordination polyhedron of Zn is a distorted octahedron with C
2 symmetry. The Zn–N distances in the coordination polyhedron are 2.117(3) and 2.131(3) Å; the Zn–Ocarb distance is 2.171(2) Å and the Zn–O(w) distance is 2.129(2) Å. The O–H···O hydrogen bonds involving the outer-sphere water molecules combine the polymer layers into a framework. 相似文献
9.
Hu Z Escamilla Ramírez DJ Heredia Cervera BE Oskam G Searson PC 《The journal of physical chemistry. B》2005,109(22):11209-11214
We report on the synthesis of ZnO particles from Zn(CH(3)CO(2))(2) in 2-propanol as a function of the concentration of water, in the absence of a base such as NaOH. Particles with diameters of 3-5 nm are formed depending on time, temperature, and water concentration. The nucleation and growth are slower than in the presence of NaOH, and at longer times the increase in particle size is dominated by diffusion-limited coarsening. The rate constant for coarsening increases with increasing water concentration up to 150 mM, above which the rate constant is 1.1 x 10(-4) cm(3) s(-1), independent of the water concentration. The width of the particle size distribution decreases with increasing water concentration, and at 250 mM water, the full width at half-maximum of the distribution function is essentially the same as for the synthesis of ZnO using NaOH as a reactant. The temperature dependence of coarsening is determined by the bulk solubility of the ZnO nanoparticles and yields an apparent activation energy of 1.12 eV. This is significantly larger than the activation energy of 0.35 eV for coarsening of ZnO from 1 mM Zn(CH(3)CO(2))(2) in 2-propanol with 1.6 mM NaOH. 相似文献
10.
A. I. Gerko 《Mathematical Notes》2005,77(1):161-171
In this paper, we consider the classical existence problem for consistent and uniformly consistent solutions of linear equations in variational derivatives. In particular, we generalize several results obtained by V. V. Zhikov and B. A. Shcherbakov concerning the existence of almost-periodic, consistent, and uniformly consistent solutions of ordinary differential equations. 相似文献