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81.
82.
2-Aminomethylpyridine readily reacted with Co(II) ion to give a chelate complex which reacted with oxygen to form, presumably, a μ-peroxodicobalt(III) complex or a Co(III)- complex, and finally it was transformed to 2,3,5,6-tetra(2-pyridyl) pyrazine. 相似文献
83.
The photochromism and rewritability of Ag-TiO2 films were deactivated by modification with thiols to make it possible to retain color images displayed on the films (for more than 3 days under white fluorescent lamps), while the deactivated properties were fully reactivated by UV-irradiation. 相似文献
84.
Yoshihisa Okamoto Yoshihisa Kurasawa Tomoji Aotsuka 《Journal of heterocyclic chemistry》1994,31(1):49-52
A novel and convenient synthesis of the title compounds 4, 5, 11 , and 13 is described, involving the ring transformation of 1,5-benzodiazepine derivatives 1a and 1b with active methylene compounds. 相似文献
85.
Deng H Press D Götzinger S Solomon GS Hey R Ploog KH Yamamoto Y 《Physical review letters》2006,97(14):146402
We study the momentum distribution and relaxation dynamics of semiconductor microcavity polaritons by angle-resolved and time-resolved spectroscopy. Above a critical pump level, the thermalization time of polaritons at positive detunings becomes shorter than their lifetime, and the polaritons form a quantum degenerate Bose-Einstein distribution in thermal equilibrium with the lattice. 相似文献
86.
Kim J Ryu D Sei Y Yamaguchi K Ahn KH 《Chemical communications (Cambridge, England)》2006,(10):1136-1138
Homochiral coordination cages, which have two well-defined internal binding sites for ammonium and organoammonium ions, have been constructed by Pd(II)-mediated self-assembly of preorganized tripodal oxazolines containing pyridine pendant groups. 相似文献
87.
In a time dependent background like de Sitter space, Feynman–Dyson perturbation theory breaks down due to infra-red divergences. We investigate an interacting scalar field theory in Schwinger–Keldysh formalism. We derive a Boltzmann equation from a Schwinger–Dyson equation inside the cosmological horizon. Our solution shows that the particle production is compensated by the reduction of the on-shell states due to unitarity. Although the degrees of freedom inside the horizon leads to a small and diminishing screening effect of the cosmological constant, there is a growing screening effect from those outside the horizon. 相似文献
88.
Yoshihisa Morita 《Journal of Applied Analysis & Computation》2012,2(1):57-71
We are dealing with a two-component system of reaction-diffusion equations with conservation of a mass in a bounded domain subject to the Neumann or the periodic boundary conditions. We consider the case that the conserved system is transformed into a phase-field type system. Then the stationary problem is reduced to that of a scalar reaction-diffusion equation with a nonlocal term. We study the linearized eigenvalue problem of an equilibrium solution to the system, and compare the eigenvalues with ones of the linearized problem arising from the scalar nonlocal equation in terms of the Rayleigh quotient. The main theorem tells that the number of negative eigenvalues of those problems coincide. Hence, a stability result for nonconstant solutions of the scalar nonlocal reaction-diffusion equation is applicable to the system. 相似文献
89.
Valli L Casilli S Giotta L Pignataro B Conoci S Borovkov VV Inoue Y Sortino S 《The journal of physical chemistry. B》2006,110(10):4691-4698
This work reports on the structural and spectroscopic properties of ethane-bridged Zn porphyrin dimers (1) in Langmuir-Sch?fer (LS) thin films by combining scanning force microscopy (SFM) with film balance, UV-vis absorption, fluorescence, and nanosecond laser flash photolysis measurements. Results show that depending on the surface pressure the Langmuir films of pure 1 can be arranged in two different condensed phases, whereas SFM of the LS films shows characteristic fractal networks constituted by nanoscopic aggregates. The spectral findings agree with a picture in which 1 is apparently present in the anti conformation but aggregated in a sort of H-type structure whose optical features resemble those of the syn conformer. This type of structure is not responsive to light stimuli. By diluting 1 in arachidic acid the porphyrin aggregation is significantly minimized with 1 exhibiting almost exclusively the anti conformation. As a result the LS films become photoresponsive, showing fluorescence emission and triplet-triplet transient absorption. 相似文献
90.
[reaction: see text] A series of modified gamma-cyclodextrins (CDs) with a flexible or rigid cap, synthesized and used as chiral supramolecular hosts for mediating the enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid, significantly improved the chemical and optical yields of chiral head-to-head cyclodimer 3, while the gamma-CD with a rigid cap dramatically inverted the stereochemical outcomes and further improved the enantioselectivities of both head-to-tail and head-to-head dimers 2 and 3. 相似文献