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DAndrea A. Tomassini N. Ferrari L. Righini M. Selci S. Bruni M. R. Simeoni G. 《Il Nuovo Cimento D》1995,17(11):1423-1427
Il Nuovo Cimento D - Normalized reflection spectra in GaInAs/GaAs quantum wells are shown for two sets of samples with different alloy concentration (x=9% and 18.5%) and well thickness ranging from... 相似文献
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Giampiero Bettinetti Milena Sorrenti Laura Catenacci Franca Ferrari Silvia Rossi Ilaria Salvadeo Paolo Carraro 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):329-332
Triacetyl α-cyclodextrin, triacetyl β-cyclodextrin and triacetyl γ-cyclodextrin were tested as possible hydrophobic carriers
to prolong the release of hydrophilic teicoplanin (TCP). Physical–chemical characterization of individual components, drug-carrier
physical mixtures at 0.5, 0.67 and 0.75 mass fraction of carrier, and the respective interaction products by kneading or evaporative
crystallization under microwave irradiation was carried out using differential scanning calorimetry (DSC) and thermogravimetric
analysis (TGA). In vitro drug release in pH 7.4 phosphate buffer at 37 °C was determined by intrinsic dissolution rate (IDR)
measurements on non disintegrating compressed discs. Solid-state interactions of TCP with triacetyl α-cyclodextrin by evaporative
crystallization and kneading and with triacetyl β-cyclodextrin by evaporative crystallization (probably resulting in carrier
amorphization) were demonstrated. The role of carrier hydrophobicity, carrier mass fraction and preparation method of solid
drug-carrier combinations on solid-state drug-carrier interactions and slowing down of TCP release was assessed. Modulation
of drug release can be achieved using TCP-triacetyl γ-cyclodextrin combinations at 0.5 mass fraction of carrier. 相似文献
5.
Archiv der Mathematik - We obtain an explicit Hölder regularity result for viscosity solutions of a class of second order fully nonlinear equations led by operators that are neither... 相似文献
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Summary We consider the one dimensional nearest neighbors asymmetric simple exclusion process with ratesq andp for left and right jumps respectively;q<p. Ferrari et al. (1991) have shown that if the initial measure isv
,
, a product measure with densities and to the left and right of the origin respectively, <, then there exists a (microscopic) shock for the system. A shock is a random positionX
t
such that the system as seen from this position at timet has asymptotic product distributions with densities and to the left and right of the origin respectively, uniformly int. We compute the diffusion coefficient of the shockD=lim
t
t
–1(E(X
t
)2–(EX
t
)2) and findD=(p–q)(–)–1((1–)+(1–)) as conjectured by Spohn (1991). We show that in the scale
the position ofX
t
is determined by the initial distribution of particles in a region of length proportional tot. We prove that the distribution of the process at the average position of the shock converges to a fair mixture of the product measures with densities and . This is the so called dynamical phase transition. Under shock initial conditions we show how the density fluctuation fields depend on the initial configuration. 相似文献
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An exact numerical analysis is given of electron waves in a pair of coupled semiconductor heterojunction electron waveguides modelled by a rectangular potential distribution. The waveguide lengths required for electron current transfer between the guides agree asymptotically with estimates from Yariv's coupled mode theory and are usefully more accurate. Moreover the electron wave coupling due to an ideal launcher can be worked out, leading to estimates of the off/on current ratio occurring in the waveguides when regarded as an ultrafast switch. For a Poisson probability distribution of the number of electrons N making up a bit-pulse, we have calculated the minimum average N, dependent upon , which would be required to keep the switching bit-error rate below prescribed limits. Pulse rise times and switching delays are derived from the explicit forms for the longitudinal electron wave group velocity. Combining the bit-error and switching-time calculations leads to estimates of the waveguide current densities which would be required in practice. Some normalized sets of curves relating to our analysis are given and used to predict the performance of particular examples of recently proposed AlGaAs/GaAs heterojunction electron waveguide switch/couplers. 相似文献
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