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1.
2.
In this study, stoichiometric protonation constants of L-tyrosine, L-cysteine, L-tryptophane, L-lysine, and L-histidine, and
their methyl and ethyl esters in water and ethanol–water mixtures of 30, 50, and 70% ethanol (v/v), were determined potentiometrically
using a combined pH electrode system calibrated as the concentration of hydrogen ion. Titrations were performed at 25∘C and the ionic strength of the medium was maintained at 0.10 mol⋅L−1 using sodium chloride. Protonation constants were calculated by using the BEST computer program. The effect of solvent composition
on the protonation constants is discussed. The log10 K2 values of esters generally decreased with increasing ethanol content. However, the log10 K1 values of the esters of L-tyrosine, L-cysteine, and L-tryptophane were found to increase with increasing ethanol content
in contrast those of L-lysine and L-histidine esters. 相似文献
3.
Suppose there exists a global solution u to the incompressible Navier–Stokes equations, such that . We prove that its norm goes to 0 at infinity. We next use this fact to control the norm of u, and finally we prove that such a solution is stable. To cite this article: I. Gallagher et al., C. R. Acad. Sci. Paris, Ser. I 334 (2002) 289–292. 相似文献
4.
Stefan Cobzaş 《Acta Appl Math》2004,80(3):363-363
5.
Mustafa Çelebier Ertan Şahin Nilgün Ancın Nurşen Altuntaş Öztaş Selma Gül Öztaş 《应用有机金属化学》2007,21(10):viii-viii
The article referenced above was first published online on 30 August 2007 with incorrect pagination; the pagination has now been corrected online and in print. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
6.
U. Turgut 《Journal of Quantitative Spectroscopy & Radiative Transfer》2004,86(4):353-359
The Coster-Kronig transition, f23, was determined using differential fluorescence cross sections of Ll X-ray for Th and U. The targets were irradiated an Am-241 radioisotope at the different incident angle. The Ll X-rays were counted with a Si (Li) detector at the different scattering angle varying from 60° to 90° at 10° intervals. For each angle, the Coster-Kronig transition probability, f23, was found. An obtained Coster-Kronig transition probability value was fitted versus emission angle. According to present results we can say that the Coster-Kronig transition probability, f23, shows isotropic distribution. 相似文献
7.
Gábor Házi 《Central European Journal of Physics》2003,1(3):453-462
A general class of analytical solutions of the lattice Boltzmann equation is derived for two-dimensional, steady-state unidirectional
flows. A subset of the solutions that verifies the corresponding Navier-Stokes equations is given. It is pointed out that
this class includes, e.g., the Couette and the Poiseuille flow but not, e.g., the basic Kolmogorov flow. For steady-state
non-unidirectional flows, first and second order solutions of the lattice Boltzmann equation are derived. Practical consequences of the analysis
are mentioned. Differences between the technique applied here and those used in some earlier works are emphasized. 相似文献
8.
9.
We continue the studies on the so–called genuine Bernstein–Durrmeyer operators U
n
by establishing a recurrence formula for the moments and by investigating the semigroup T(t) approximated by U
n
. Moreover, for sufficiently smooth functions the degree of this convergence is estimated. We also determine the eigenstructure
of U
n
, compute the moments of T(t) and establish asymptotic formulas.
Received: January 26, 2007. 相似文献
10.
We give a concise review and extension of S-procedure that is an instrumental tool in control theory and robust optimization analysis. We also discuss the approximate S-Lemma as well as its applications in robust optimization.The many suggestions and detailed corrections of an anonymous referee are gratefully acknowledged. 相似文献