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991.
Simple contactless cells with planar or tubular electrodes have been designed for measurement of the permittivity of solutions. The cells, connected to an integrated circuit of astable multivibrator, respond primarily to the capacitance component of the cell impedance, the multivibrator frequency depends in a defined manner on the solution permittivity and is readily used as the analytical signal in determinations of the ratios of components in binary liquid mixtures; water solution of methanol, ethanol and dioxane have been tested. The response of the cell with planar electrodes satisfies well the simple theoretical model and both the cells provide results with a sufficient sensitivity, a low LOD value (units of %vol) and a good precision (around 1%rel). The cell simplicity, small dimensions, long‐term stability and the possibility of powering them from a battery make them suitable for hand‐held meters. As an example of application in practice, the content of ethanol was determined in the car fuel petrol. 相似文献
992.
A procedure for identification of malting barley varieties using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) of ethanol‐soluble barley proteins (hordeins) is described. The hordeins were first extracted from milled barley grains by several extraction protocols (using different extraction agents and conditions). Hordein extracts were then analyzed directly via MALDI‐TOF MS without any preliminary purification or separation step, and the protein profiles of analyzed hordein extracts were compared in order to find out the most suitable extraction procedure for mass spectrometric analysis. The optimized procedure was successfully applied to identification of 13 malting barley varieties. Our results revealed that the proposed mass spectrometry‐based approach provides characteristic mass patterns of extracted hordeins, which can be advantageously used for barley variety identification. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
993.
Summary: High-impact polystyrene (HIPS) is a hetero-phase polymer with the so-called salami morphology. Salami morphology is formed by a continuous PS phase containing micron-sized PB domains. PB domains contain submicron-sized irregular PS occlusions. In our modeling work we addressed several weak points of Cahn-Hilliard model of HIPS salami morphology evolution. The weakest point of Cahn-Hilliard model is the inherently present Ostwald ripening destabilizing or competing with graft-stabilized domains. Two mechanism of formation of HIPS morphology are supported by the model: (i) encapsulation of graft-stabilized PS-rich domains in PB particles, and (ii) polymerization of styrene dissolved in PB-rich phase and subsequent phase separation leading to PS occlusions in PB domains. 相似文献
994.
Zoran Šunić 《Archiv der Mathematik》2009,93(1):23-28
Baer characterized capable finite abelian groups (a group is capable if it is isomorphic to the group of inner automorphisms
of some group) by a condition on the size of the factors in the invariant factor decomposition (the group must be noncyclic
and the top two invariant factors must be equal). We provide a different characterization, given in terms of a condition on
the lattice of subgroups. Namely, a finite abelian group G is capable if and only if there exists a family {H
i
} of subgroups of G with trivial intersection, such that the union generates G and all quotients G/H
i
have the same exponent. Other variations of this condition are also provided (for instance, the condition that the union
generates G can be replaced by the condition that it is equal to G).
The work presented here is partially supported by NSF/DMS-0805932. 相似文献
995.
We present a new method of investigating the so-called quasi-linear strongly-damped wave equations
996.
Alexandru Kristály Csaba Varga 《Journal of Mathematical Analysis and Applications》2009,352(1):139-148
Some multiplicity results are presented for the eigenvalue problem
(Pλ,μ) 相似文献
997.
Peter Baláž Parviz Pourghahramani Erika Dutková Martin Fabián Jaroslav Kováč Alexander Šatka 《Central European Journal of Chemistry》2009,7(2):215-221
PbS nanocrystals using surfactant assisted mechanochemical route has been successfully prepared. The methods of XRD, SEM,
surface area and particle size measurements were used for nanocrystals characterization. The XRD patterns confirmed the presence
of galena PbS (JCPDS 5–592) whatever treatment conditions were applied. The strong observable peaks indicate the highly crystalline
nature in formation of PbS nanostructures where preferential crystal growth in the (200) direction after chelating agent (EDTANa2•2H2O) addition has been observed. The mean volume weighted crystallite size 4.9 nm and 35 nm has been calculated from XRD data
using Williamson-Hall method for PbS synthesized without and/or with chelating agent, respectively corresponding with surface
weighted crystallites sizes of 2.9 and 18.8 nm. The sample prepared without surfactant yields the smaller crystallites and
the higher microstrain compared with surfactant assisted synthesis. The obtained results illustrate a possibility to manipulate
crystal morphology by combining effect of milling and surfactant application.
相似文献
998.
In this paper we study the tail behaviour of the probability of ruin within finite time t, as initial risk reserve x tends to infinity, for the renewal risk model with strongly subexponential claim sizes. The asymptotic formula holds uniformly for t∈[f(x), ∞), where f(x) is an infinitely increasing function, and substantially extends the result of Tang (Stoch. Models 2004; 20 :281–297) obtained for the class of claim distributions with consistently varying tails. Two examples illustrate the result. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
999.
1000.