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101.
102.
103.
Molecular weight dependent charge carrier mobility in poly(3,3' '-dioctyl-2,2':5',2' '-terthiophene)
Verilhac JM Pokrop R LeBlevennec G Kulszewicz-Bajer I Buga K Zagorska M Sadki S Pron A 《The journal of physical chemistry. B》2006,110(27):13305-13309
Poly(3,3' '-dioctyl-2,2':5',2' '-terthiophene), a polymer recently used for the fabrication of organic field effect transistors, has been fractionated into five fractions distinctly differing in their molecular weights (Mn), with the goal of determining the influence of the degree of polymerization (DPn) on its principal physicochemical parameters. It has been demonstrated that within the Mn range studied (from 1.5 kDa to 10.5 kDa by SEC), corresponding to DPn from 10 to 38, the polymer band gap steadily decreases with growing molecular weight, which is clearly manifested by an increasing bathochromic shift of the band originating from the pi-pi* transition. The same trend is observed for the HOMO level, determined from the onset of the p-doping in cyclic voltammetry, which shifts from -5.10 eV to -4.90 eV for the lowest and the highest molecular weight fractions, respectively. The most pronounced influence of DPn has been found for the charge carriers' mobility-one of the most important parameters of field effect transistors (FETs) fabricated from this polymer. A fourfold increase in DPn results in an increase of the carriers' mobility by more than 3 orders of magnitude. Comparison of these results with those obtained for fractionated regioregular poly(3-hexylthiophene) shows a strikingly similar behavior of both polymers with respect to the molecular weight. 相似文献
104.
Hernán J. Cervantes Antonio C. Bloise Said R. Rabbani 《Applied magnetic resonance》2010,38(4):417-429
In this paper, we propose a new method of measuring the very slow paramagnetic ion diffusion coefficient using a commercial
high-resolution spectrometer. If there are distinct paramagnetic ions influencing the hydrogen nuclear magnetic relaxation
time differently, their diffusion coefficients can be measured separately. A cylindrical phantom filled with Fricke xylenol
gel solution and irradiated with gamma rays was used to validate the method. The Fricke xylenol gel solution was prepared
with 270 Bloom porcine gelatin, the phantom was irradiated with gamma rays originated from a 60Co source and a high-resolution 200 MHz nuclear magnetic resonance (NMR) spectrometer was used to obtain the phantom 1H profile in the presence of a linear magnetic field gradient. By observing the temporal evolution of the phantom NMR profile,
an apparent ferric ion diffusion coefficient of 0.50 μm2/ms due to ferric ions diffusion was obtained. In any medical process where the ionizing radiation is used, the dose planning
and the dose delivery are the key elements for the patient safety and success of treatment. These points become even more
important in modern conformal radio therapy techniques, such as stereotactic radiosurgery, where the delivered dose in a single
session of treatment can be an order of magnitude higher than the regular doses of radiotherapy. Several methods have been
proposed to obtain the three-dimensional (3-D) dose distribution. Recently, we proposed an alternative method for the 3-D
radiation dose mapping, where the ionizing radiation modifies the local relative concentration of Fe2+/Fe3+ in a phantom containing Fricke gel and this variation is associated to the MR image intensity. The smearing of the intensity
gradient is proportional to the diffusion coefficient of the Fe3+ and Fe2+ in the phantom. There are several methods for measurement of the ionic diffusion using NMR, however, they are applicable
when the diffusion is not very slow. 相似文献
105.
An efficient method for preparation of 4,6 or 5,6 disubstituted 3-aminopyridazines was easily carried out starting from easily available 4-bromo-pyridazine-3,6-dione, and using combination of both amination and Pd(0) cross-coupling reactions under microwave irradiation. 相似文献
106.
In this work we consider a nonlinear hyperbolic one-dimensional viscoelastic nonlocal problem with a nonlocal boundary condition.
We establish a blow up result for large initial data and a decay result for small enough initial data. 相似文献
107.
108.
1H-NMR spectrum of tiaprofenic acid in CDCI3 was obtained and proton chemical shifts from tetramethylsilane were assigned to each proton and set of equivalent protons of the molecule. The hydroxy proton of the carboxylic acid group was confirmed by deuterium exchange. The natural abundance C-13 nuclear magnetic resonance spectrum of the compound in CDCI3 was recorded using Fourier transorm technique. The chemical shifts of carbon resonances have been assigned on the basis of the chemical shift additivity theory and the signal multiplicity observed in the single frequency off-resonance decoupled (SFORD) spectrum. Also comparison with carbon chemical shifts of model compounds were useful. 相似文献
109.
We prove that any Lie algebra g over a field K of characteristic zero admitting a unique up to a constant quadratic structure is necessarily a simple Lie algebra. If the field K is algebraically closed, such condition is also sufficient. Further, a real Lie algebra g admits a unique quadratic structure if and only if its complexification gC is a simple Lie algebra over C 相似文献
110.
Let R be an integral domain with quotient field F. It is shown that R is a strongly discrete Prüfer v-multiplication domain if and only if there exists a bijection between the set of the prime w-ideals and the set of isomorphism classes of GV-torsionfree indecomposable injective R-modules and every indecomposable injective R-module, viewed as a module over its endomorphism ring, is uniserial. It is also shown that the w-closure of any GV-torsionfree homomorphic image of F is injective if and only if R is a Prüfer v-multiplication domain satisfying an almost maximality-type property. 相似文献