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121.
Fluorescent whitening agents (FWA) are used to improve the whiteness of cellulose fabrics. It is well known but not completely understood that the fluorescence decreases (chemical and physical mechanisms of distinguishing) above a certain FWA concentrationc
crit. This reduction of fluorescence correlates very well with the alteration of the adsorption process studied by calorimetry and zeta potential measurements. The results obtained by these methods indicate that the adsorption mechanism is different at concentrations below and abovec
crit. The reduction of the intensity of fluorescence, the degree of whiteness and the zeta potential are caused by the adsorption of a second layer of fluorescent whitening agents. This second layer reduces the zeta potential due to a shielding effect and reduces the whiteness and fluorescence by a bathochromic shift of the reflection curves. The final effect is a reduction of the total reflection. 相似文献
122.
V. N. Sorokin 《Mathematical Notes》2007,81(5-6):817-826
We propose a new method for proving the Zudilin-Rivoal theorem stating, in particular, that the sequence of values of the Dirichlet beta function at even natural points contains infinitely many irrational values. For polylogarithms, we use Hermite—Padé approximations of the first type, invariant with respect to the Klein group. Quantitative additions to this theorem are obtained. 相似文献
123.
Yilmaz Simsek 《Journal of Mathematical Analysis and Applications》2006,318(1):333-351
The main purpose of this paper is to define new generating functions. By applying the Mellin transformation formula to these generating functions, we define q-analogue of Riemann zeta function, q-analogue Hurwitz zeta function, q-analogue Dirichlet L-function and two-variable q-L-function. In particular, by using these generating functions, we will construct new generating functions which produce q-Dedekind type sums and q-Dedekind type sums attached to Dirichlet character. We also give the relations between these sums and Dedekind sums. Furthermore, by using *-product which is given in this paper, we will give the relation between Dedekind sums and q-L function as well. 相似文献
124.
Djurdje Cvijovi? 《Journal of Mathematical Analysis and Applications》2007,332(2):1056-1062
We, by making use of elementary arguments, deduce integral representations of the Legendre chi function χs(z) valid for |z|<1 and Res>1. Our earlier established results on the integral representations for the Riemann zeta function ζ(2n+1) and the Dirichlet beta function β(2n), n∈N, are a direct consequence of these representations. 相似文献
125.
Avinash Khare 《Pramana》1997,48(2):537-553
We, offer an alternative interpretation of the Riemann zeta functionζ(s) as a scattering amplitude and its nontrivial zeros as the resonances in the scattering amplitude. We also look at several
different facets of the phase of theζ function. For example, we show that the smooth part of theζ function along the line of the zeros is related to the quantum density of states of an inverted oscillator. On the other
hand, for ℜs>1/2, we show that the memory of the zeros fades only gradually through a Lorentzian smoothing of the delta functions. The
corresponding trace formula for ℜs≫1 is shown to be of the same form as generated by a one-dimensional harmonic oscillator in one direction along with an inverted
oscillator in the transverse direction. Quite remarkably for this simple model, the Gutzwiller trace formula can be obtained
analytically and is found to agree with the quantum result. 相似文献
126.
The estimation of energy barrier to detachment of particles from a substrate was carried out. Detachment processes of 4 m polyethylene particles from a quartz wall under the gravitational force in aqueous solutions were investigated by a direct observation technique. The magnitude of energy barriers was experimentally determined by the temperature dependence of the rate constant of detachment and was compared with that estimated theoretically from the superposition of electrostatic and London—van der Waals energies calculated using the experimental electrokinetic potentials and Hamaker constants, respectivley. Both were in fairly good agreement. 相似文献
127.
Per Dahlqvist 《Journal of statistical physics》1996,84(3-4):773-795
We compute the Lyapunov exponent, the generalized Lyapunov exponents, and the diffusion constant for a Lorentz gas on a square lattice, thus having infinite horizon. Approximate zeta functions, written in terms of probabilities rather than periodic orbits, are used in order to avoid the convergence problems of cycle expansions. The emphasis is on the relation between the analytic structure of the zeta function, where a branch cut plays an important role, and the asymptotic dynamics of the system. The Lyapunov exponent for the corresponding map agrees with the conjectured limit map = -2 log(R) + C + O(R) and we derive an approximate value for the constantC in good agreement with numerical simulations. We also find a diverging diffusion constantD(t)logt and a phase transition for the generalized Lyapunov exponents. 相似文献
128.
Nurfer Güngör Sükran Dilmac 《Journal of inclusion phenomena and macrocyclic chemistry》1996,26(1-3):93-101
The values of the zeta potentials for bentonitic clay particles suspended in solutions of NaCl, (NaPO3)
n
and CaCl2 at different electrolyte concentrations and constant pH(7) were measured. When Ca salts were added to the clay solutions in increasing concentrations, the double layers of particle surfaces gradually contract, become narrower and the zeta potential value decreases. When Na salts were used, the zeta potential increased with increasing concentration.Presented at the Sixth International Seminar on Inclusion Compounds, Istanbul, Turkey, 27–31 August, 1995. 相似文献
129.
Turgeman R Tirosh S Gedanken A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(7):1845-1850
We report herein on the oriented growth of ZnO crystals on magnetite nanoparticles. The ZnO crystals were grown by hydrolyzing a supersaturated aqueous solution of zinc nitrate. The seeds for the growth were magnetite nanoparticles with a diameter of 5.7 nm and a narrow size distribution. Hollowed ZnO hexagons of 0.15 microm width and 0.5 microm length filled with Fe(3)O(4) particles were obtained. HR-TEM (high-resolution transmission electron microscopy) and selected-area EDS (energy-dispersive spectroscopy) show that the nanoparticles are homogenously spread in the ZnO tubes. Zeta potential measurements were employed to understand the relationship between the nanoparticles and the oriented growth of the ZnO crystals. The results show that the surfactants induced the directional growth of the ZnO crystals. 相似文献
130.
Rapid coalescence was studied on liquid paraffin emulsion stabilized with a series of poly(oxyethylene) dodecyl ethers [C12H25 (EO),n=1, 2, 3, 4, 5, 6, 7, 8] and of poly(oxyethylene) nonylphenyl ethers [C9H19(EO)
n
,n=2, 4, 5, 6, 12]. The turbidity of emulsion was measured as a function of the solution pHs at constant ionic strength of 0.1 mol dm–3.As a result, it was found that the emulsions (which were formed with C12H25(EO)
n
surfactants having less than four oxyethylene groups, or with C9H19 (EO)
n
surfactants having less than six oxyethylene groups) brought about rapid coalescence in the bulk pH between 2.03.5, which corresponded to the zero point of charges for the emulsions of the present systems. According to the Tadros treatment for emulsion flocculation, the total flocculation potennual was estimated as a function of the distance relative to the number of oxyethelene groups in the surfactants. The critical coalescence energy was obtained as –343 ×10–19 J for the C12H25(EO)
n
surfactants and –2.14×10–19) J for the C9H19 (EO)
n
surfactants. Furthermore, the formation of a hole for coalescence was estimated under the simple assumption that the coalescence was caused only by the energy dissipation. 相似文献