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51.
B. Hinkelmann 《Rheologica Acta》1982,21(4-5):491-493
From literature some representative equations have been compiled describing the influence of filler on the viscosity of polymer melts. By application of these on the experimental results obtained from GF-SAN it was found that the relative viscosity
R
, i.e. the ratio of the viscosities of the filled and unfilled melt, shows a pronounced dependence on the shear rate
but not on the shear stress. Defining
R
with constant and not with constant
(as it is usually done), an analytical approach is possible independent of
Further the influence of pressure, temperature and filler content on the zero-shear viscosity of filled polymer melts may be expressed by a modified Arrhenius equation. 相似文献
52.
Ottosson N Børve KJ Spångberg D Bergersen H Sæthre LJ Faubel M Pokapanich W Öhrwall G Björneholm O Winter B 《Journal of the American Chemical Society》2011,133(9):3120-3130
The local electronic structure of glycine in neutral, basic, and acidic aqueous solution is studied experimentally by X-ray photoelectron spectroscopy and theoretically by molecular dynamics simulations accompanied by first-principle electronic structure and spectrum calculations. Measured and computed nitrogen and carbon 1s binding energies are assigned to different local atomic environments, which are shown to be sensitive to the protonation/deprotonation of the amino and carboxyl functional groups at different pH values. We report the first accurate computation of core-level chemical shifts of an aqueous solute in various protonation states and explicitly show how the distributions of photoelectron binding energies (core-level peak widths) are related to the details of the hydrogen bond configurations, i.e. the geometries of the water solvation shell and the associated electronic screening. The comparison between the experiments and calculations further enables the separation of protonation-induced (covalent) and solvent-induced (electrostatic) screening contributions to the chemical shifts in the aqueous phase. The present core-level line shape analysis facilitates an accurate interpretation of photoelectron spectra from larger biomolecular solutes than glycine. 相似文献
53.
Ramón Martínez-Máñez Félix Sancenón Mandy Hecht Mustafa Biyikal Knut Rurack 《Analytical and bioanalytical chemistry》2011,399(1):55-74
This review highlights how the combination of supramolecular principles and nanoscopic solid structures enables the design
of new hybrid sensing ensembles with improved sensitivity and/or selectivity and for the targeting of analytes for which selectivity
is hard to achieve by conventional methods. Such ideas are bridging the gap between molecules, materials sciences and nanotechnology.
Relevant examples will be detailed, taking into account functional aspects such as (1) enhanced coordination of functionalized
solids, (2) enhanced signalling through preorganization, (3) signalling by assembly–disassembly of nanoscopic objects, (4)
biomimetic probes utilizing discrimination by polarity and size and (5) distinct switching and gating protocols. These strategies
are opening new prospects for sensor research and signalling paradigms at the frontier between nanotechnology, smart materials
and supramolecular chemistry. 相似文献
54.
Mykhaylo Chursin Lars Sch?fer Knut Smoczyk 《Calculus of Variations and Partial Differential Equations》2011,41(1-2):111-125
Given an almost para-K?hler manifold equipped with a metric and para-complex connection, we define a generalized second fundamental form and generalized mean curvature vector of space-like Lagrangian submanifolds. We then show that the deformation induced by this variant of the mean curvature vector field preserves the Lagrangian condition, if the connection satisfies also some Einstein condition. In case the almost para-K?hler structure is integrable, the flow coincides with the classical mean curvature flow in the pseudo-Riemannian context. 相似文献
55.
Michael Seth Peter Schwerdtfeger Michael Dolg Knut Faegri Bernd A. Hess Uzi Kaldor 《Chemical physics letters》1996,250(5-6):461-465
Relativistic and electron correlation contributions in the hydride of the recently discovered superheavy element 111 were studied using ab-initio methods within different relativistic approaches. Relativistic effects decrease the (111)H bond distance by 0.42 Å. As a result of this large bond contraction, the bond distance of (111)H (1.51 Å) is comparable to that of the hydride of its lighter congener AuH (1.52 Å), but below that of AgH (1.60 Å). The dissociation energy is relativistically increased by approximately 1.2 eV and the stretching force constant is more than quadrupled from 1.1 mdyn/Å at the nonrelativistic level to 5.0 mdyn/Å at the relativistic level. 相似文献
56.
57.
Knut Deimer 《Combinatorica》1985,5(2):109-120
Ad-dimensional circuit code of spreads is a simple circuitC in the graph of thed-dimen sional unit cube with the property that for any verticesx andy ofC which differ in exactlyr co-ordinates,r<s, there exists a path fromx toy consisting ofr edges ofC. This property is useful for detecting and limiting errors. In this paper we give a new upper bound for the maximum length
of ad-dimensional circuit code of spread 2. 相似文献
58.
59.
Knut Reiner Rainer Richter Siegfried Hauptmann Jan Becher Lothar Hennig 《Tetrahedron》1995,51(48):13291-13300
A series of pyrazole type tetrakis compounds has been synthesized by reaction of aromatic or heterocyclic dialdehydes and pyrazolone derivatives. Structure and tautomerism of the products were investigated by spectroscopic methods and X-ray analysis. Several tetrakis compounds form inclusion complexes with solvents like alcohols, ethers, and ketones in a definite ratio via hydrogen bonds. 相似文献
60.