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141.
JPC – Journal of Planar Chromatography – Modern TLC - A simple and rapid densitometric thin-layer chromatographic method, suitable for monitoring the histamine content of fish and... 相似文献
142.
The origin of the change of the thermodynamic properties of association between homogeneous and heterogeneous systems is highlighted by numerical experiments. 相似文献
143.
Gaël Raoul 《Monatshefte für Mathematik》2012,165(1):117-144
In this paper, we are interested in the nonlinear stability of Dirac-type steady solutions to an integro-differential equation appearing in the study of populations which are structured with respect to a quantitative (continuous) trait. We show that stability conditions of Adaptive Dynamics extend to this model. 相似文献
144.
145.
Gregory Kennedy Cornelia Chilian Radojko Jaćimović Gašper Žerovnik Luka Snoj Andrej Trkov 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(2):555-559
In order to predict the self-shielding effect in neutron activation of non-spherical samples in reactor neutron spectra, it
is important to know whether the neutron field is sufficiently anisotropic to cause significant variations between horizontal
and vertical sample orientation or with orientation relative to the direction towards the reactor core. Metal wires with significant
neutron self-shielding were irradiated in several channels of the SLOWPOKE reactor at Ecole Polytechnique Montreal and the
TRIGA reactor at the Jožef Stefan Institute. In all cases, the amount of thermal or epithermal self-shielding was found to
be identical, within the experimental uncertainty, regardless of the orientation of the wire, indicating that the neutron
field is essentially isotropic. Models used to predict neutron self-shielding need to be adjusted accordingly. In our Monte
Carlo model, the tube-shaped neutron source was moved back into the moderator and reflecting materials near the sample location
were included, which produced an isotropic neutron field at the sample location. 相似文献
146.
Hugo Festjens Chevallier Gaël Renaud Franck Dion Jean-Luc Lemaire Remy 《Applied Acoustics》2012,73(11):1121-1128
The purpose of this publication is to give an overview of the actual role of multi-layered viscoelastic parts, so called “shims”, to prevent squeal noises of automotive brake systems. Since shear stress is usually used to damp thin structures in their bending modes it is commonly believed to be the largest underwent by shims. To check this assumption and considering that stresses underwent by shims cannot be measured experimentally, the authors have computed them with the help of a detailed and realistic finite element model. Contrary to what shims manufacturers say, this study exhibits the fact that shims are almost uniquely solicited in their normal direction in brake systems. Secondly, the study focuses on the added damping and stiffening induced by the viscoelastic materials. In order to take into account these materials, a realistic frequency dependent viscoelastic behavior has been integrated in the simulations. Finally, the study shows certains eigenmodes for which the viscoelastic behavior of the shims reveals instabilities that would not exist without it. It is shown that this is due to coalescence phenomenon. 相似文献
147.
Catalina Gómez Jean-Luc Putaux Iñaki Mondragon Cristina Castro Piedad Gañán 《Composite Interfaces》2013,20(1):29-37
Cellulose microfibrils extracted by various alkaline treatments of vascular bundles from banana rachis were used to elaborate films. The films were comparatively studied to determine changes in polarity induced by various treatments. Atomic force microscopy was used to characterize the surface morphology of the films and transmission electron microscopy was employed to characterize the microfibrils used to elaborate the films. Contact angles were measured to determine surface free energy (SFE) and thermogravimetric analyses were carried out to determine changes in composition of the films. The results showed that the films of cellulose microfibrils prepared by the peroxide alkaline (PA) and peroxide alkaline-hydrochloric acid (PA-HCl) treatments had lower content of non-cellulosic constituents like xylose and had lower SFE than films of microfibrils treated with KOH-5. Furthermore, specimens treated with the most concentrated KOH solution (18 wt%) and sodium chloride presented the highest SFE and polar component. 相似文献
148.
The paper deals with the chemical and physical factors influencing the stoichiometry of thermal decomposition of solid coordination compounds. Nickel(II) coordination compounds were used as examples: the problem of the relationship between the structure of the initial compound (and of its intermediates) and the stoichiometry of thermal decomposition is discussed; experimental conditions are shown to affect this decomposition, and the conceptions of the apparent and real stoichiometries of thermal decomposition are discussed. The results obtained may have a more general meaning.
Reported at the 7th Seminar on Modern Methods in Inorganic Chemistry. Harmonia-Bratislava, 1977. 相似文献
Zusammenfassung Der Beitrag befa\t sich mit den chemischen und physikalischen Faktoren, welche die Stöchiometrie der thermischen Zersetzung fester Koordinationsverbindungen beeinflussen. Koordinationsverbindungen von Nickel(II) wurden als Beispiel eingesetzt; das Problem des Zusammenhanges zwischen Struktur der Ausgangsverbindung (und seiner IntermediÄrprodukte) und der Stöchiometrie der thermischen Zersetzung wird erörtert; die die Zersetzung beeinflussenden Versuchsbedingungen werden gezeigt und das Konzept der sogenannten scheinbaren und tatsÄchlichen Stöchiometrie der thermischen Zersetzung wird beschrieben. Die erhaltenen Ergebnisse dürften von allgemeinerer Bedeutung sein.
Résumé L'article considère les facteurs chimiques et physiques qui influencent la stchiométrie des réactions de décomposition thermique des composés de coordination solides. Les composés de coordination du nickel(II) ont été choisis pour illustrer le problème des relations entre la structure du composé initial (et de ses intermédiaires) et la stchiométrie de la réaction de décomposition thermique. On montre que les conditions expérimentales influencent la décomposition et on discute le principe des réactions stchiométriques de décomposition thermique dites «apparentes» et «réelles». Les résultats obtenus sont probablement de portée plus générale.
, . $ (II) $ ( ) $ . , $ , $ . .
Reported at the 7th Seminar on Modern Methods in Inorganic Chemistry. Harmonia-Bratislava, 1977. 相似文献
149.
Various approaches and standards for transferring mathematical objects between different computer programs in multimedia environment in the framework of the OpenMath project are described. The use of these standards might revolutionize the exchange of mathematical information caused by the development of computer algebra tools and telecommunication possibilities. The standards make it possible to create databases and easily save and use mathematical objects obtained in different applications, e.g., to exchange the data obtained in different computer algebra systems and place information on the Internet. Bibliography: 9 titles. 相似文献
150.
In this paper, a symmetric nonnegative matrix with zero diagonal and given spectrum, where exactly one of the eigenvalues is positive, is constructed. This solves the symmetric nonnegative eigenvalue problem (SNIEP) for such a spectrum. The construction is based on the idea from the paper Hayden, Reams, Wells, “Methods for constructing distance matrices and the inverse eigenvalue problem”. Some results of this paper are enhanced. The construction is applied for the solution of the inverse eigenvalue problem for Euclidean distance matrices, under some assumptions on the eigenvalues. 相似文献