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341.
IvanG. Scheblykin VladimirI. Arkhipov Mark VanderAuweraer Frans DeSchryver 《Helvetica chimica acta》2001,84(12):3616-3627
A clear complementary relationship between photoluminescent (PL) and electroluminescent (EL) images was observed for organic light‐emitting diodes (OLEDs) based on poly(phenylenevinylene) (PPV) and dye‐doped PPV. So‐called ‘black spots' (dark circular regions observed on the active area of running OLEDs) become bright ones, when the photoluminescence of the same area is excited. A very small thickness of the active layer (ca. 10 nm) was the crucial point to observe this anticorrelation between EL and PL. A substantial increase of the PL yield (‘anti‐burning' effect) was observed after strong light exposure (ca. 10 mJ/cm2) of the polymer covered by an aluminium layer. The same light exposure without aluminium protection resulted in complete photobleaching of the polymer. The presence of a thin insulating layer between the polymer and aluminium was proposed to be responsible for these effects. This layer prevents electron injection and PL quenching due to exciton dissociation at the metal‐polymer interface. The former effect leads to black spots in the EL image, the latter one gives rise to bright spots on the PL image situated on the same places. The intermediate layer can be also induced by light exposure. A very efficient energy transfer from the polymer to the dye and to the J‐aggregates of the dye was demonstrated in PPV/dye composite films. 相似文献
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344.
Tanja van Mourik Robert Jan Vos Joop H. van Lenthe Frans B. van Duijneveldt 《International journal of quantum chemistry》1997,63(4):805-815
A method is devised for dealing with almost linearly dependent basis sets that contain large sets of bond functions. Using the largest of such basis sets, LARSAT, the second-order Møller-Plesset polarization dispersion energy of the helium dimer is calculated to be - 17.08 K at R = 5.6 bohrs. MR-SDCI calculations, employing a set of 37 reference configurations, were performed for the helium dimer with several basis sets at 4.0 and 5.6 bohrs. Size-extensivity corrections were included to take into account the R dependency of the size-extensivity error in MR-SDCI calculations. The He2 interaction energies computed with basis LARSAT are - 10.92 K at 5.6 bohrs and 295.1 K at 4.0 bohrs. The 37-MR-SDCI calculations with basis LARSAT almost reproduce the He2 full configuration interaction (CI) interaction energies computed with the same basis, at notably smaller cost. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 63: 805–815, 1997 相似文献
345.
Noël Boens Els Cielen Kristof Van Werde Frans C. De Schryver 《Journal of fluorescence》1999,9(2):103-110
A test based on time-resolved fluorescence experiments (Anal. Biochem.
245, 28–37, 1997) allows one to assess the interference of the excited-state association with the fluorimetric determination of the ground-state dissociation constant K
d of fluorescent ion:indicator complexes. If an inflection point occurs in the plot of the fluorescence signal vs – log[ion] in the ion concentration range where both decay times are invariant, this inflection point can be associated with the correct K
d. Here we apply this test to the fluorescent ion indicators SBFO (for Na+), Mag-fura-2 (for Mg2+), and APTRA-BTC (for Ca2+). In all three cases the decay times are invariant in the concentration ranges of the respective ions where the fluorescence titrations show unique inflection points, indicating that the fluorimetrically determined K
d values are the true K
d values. 相似文献
346.
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348.
An 1,10-anthraquinone - stabilized only by alkylgroups - is prepared (in a four step synthesis) and described for the first time. 相似文献
349.
Frans Lemeire 《BIT Numerical Mathematics》1976,16(2):143-145
An equilibration is introduced that minimizes the maximum ratio of the upper bounds for the backward rounding error and the inherent error in the given data. This can be applied to the solution of systems of linear equations and to the linear eigenproblem. 相似文献
350.