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281.
Artur Seher und Chang Kin Moon 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1978,167(2):82-86
Zusammenfassung Die Ergebnisse von Ölgehaltsbestimmungen sind abhängig von der benutzten Methode und den angewandten Lösungsmitteln. Bei Extraktionen nach dem Durchtropf Verfahren werden zunehmende Extraktausbeuten in der Reihe n-Pentan, Hexan, n-Heptan gefunden, während bei Extraction im Soxhlet-Apparat n-Heptan eine viel kleinere Ausbeute liefert als die beiden anderen Solventien. Der Gehalt der Extrakte an Phospholipiden ist von der Methode wenig abhängig und wird im wesentlichen nur von der Art des Lösungsmittels bestimmt. Bei den verschiedenen Extraktionen variiert nicht nur die Menge der erhaltenen Phospholipide, auch die Zusammensetzung weist prinzipielle Unterschiede auf.
Herrn Prof. Dr. L. Acker zum 65. Geburtstag in Dankbarkeit und Freundschaft zugeeignet 相似文献
Solubility of phospholipids in oilseeds depending on the extraction conditions
Summary The results of the determination of oil content depend on the method and on the solvent used. Extractions by the Twisselmann method give increasing yields in the order n-pentane, hexane, and n-heptane. Using the Soxhlet extraction, much lower yields were obtained with n-heptane than with the other two solvents. In both methods, the phospholipid content in the extracts depends only on the solvent and not on the method used. The yield and composition of the mixture of phospholipids vary in the different methods of extraction.
Herrn Prof. Dr. L. Acker zum 65. Geburtstag in Dankbarkeit und Freundschaft zugeeignet 相似文献
282.
A scientific type of applied psychology has failed to develop within the profession of psychology. The reasons for the failure seem to lie in the historically continuous opposition of the educated academicians to the practical and applied science. They place understanding and theory construction above useful action. The establishment of schools of Applied Psychology could solve many of the problems of the development of engineering and technology of behaviour. They would permit the concentration of useful psychological expertise under one roof, the development of psychological applied services to the community within the academic framework of training and research, and they would provide opportunity for training psychologists in personal responsibility, to replace the present reliance on the medical and educational professions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
283.
Poly(3,4-dialkoxythiophene) films with different length of alkyl chain (1,3 and 8 carbon atoms) were obtained on Pt and ITO electrodes from the monomer solutions in acetonitrile by cyclic voltammetry (CV). The properties of the resulting films were studied by electrochemical methods, UV-Vis, FTIR and NMR spectra. The CVs were correlated with differential cyclic voltabsorptograms (DCVA) recorded at the absorption maxima to explain the shape of the voltammograms of the polymers studied, dependent on the alkyl-chain length in alkoxy group. The presence of the zones of different crystallinity in the polymer film was postulated. Significant influence of the type of the solvent on asymmetry of the cyclic voltammograms for the polymer doping-undoping has been discussed in terms of the solvent interaction with radical cation (polaron) delocalized on the alkoxy side groups. The polaron delocalization was proved by 1H-NMR spectra. Appearance of infrared activated vibrations (IRAVs) in the range 1500-600 cm−1 and a characteristic electronic band at 3300 cm−1 at the polarization potential +0.25 V versus Ag/Ag+ and their gradual changes upon further polymer oxidation were interpreted in terms of evolution of different charge carriers in lightly and heavily doped polymer. 相似文献
284.
285.
本文强调了创新在社会经济发展中的重要作用,指出创新政策在边缘区域的发展,其首要问题是机构能力建设。通过葡萄牙阿威罗确定区域发展机构概念设计的过程,作者分析了边缘区域学术体系和生产体系之间缺乏互动与合作的现状,探讨如何通过方法论和功能目标的设计与实施,来逐步加强区域机构的建设和区域互动能力。 相似文献
286.
287.
Artur Santos João Marcelo Teixeira Thiago Farias Veronica Teichrieb Judith Kelner 《International journal of parallel programming》2012,40(3):331-352
Current GPU computational power enables the execution of complex and parallel algorithms, such as ray tracing techniques supported
by kD-trees for 3D scene rendering in real time. This work describes in detail the study and implementation of eight different
kD-tree traversal algorithms using the parallel framework NVIDIA Compute Unified Device Architecture, in order to point their
pros and cons regarding performance, memory consumption, branch divergencies and scalability on multiple GPUs. In addition,
two new algorithms are proposed by the authors based on this analysis, aiming to performance improvement. Both of them are
capable of reaching speedup gains up to 3 × when compared to recent and optimized parallel traversal implementations. As a
consequence, interactive frame rates are possible for scenes with 1,408 × 768 pixels of resolution and 3.6 million primitives. 相似文献
288.
Systems of equations of the form X i =φ i (X 1,…,X n ) (1≤ i ≤ n) are considered, in which the unknowns are sets of natural numbers. Expressions φ i may contain the operations of union, intersection and elementwise addition \(S+T=\{m+n\mid m\in S\), n∈T}. A system with an EXPTIME-complete least solution is constructed in the paper through a complete arithmetization of EXPTIME-completeness. At the same time, it is established that least solutions of all such systems are in EXPTIME. The general membership problem for these equations is proved to be EXPTIME-complete. Among the consequences of the result is EXPTIME-completeness of the compressed membership problem for conjunctive grammars. 相似文献
289.
Artur Czumaj Robert Elsässer Leszek Gąsieniec Thomas Sauerwald Xin Wang 《Distributed Computing》2013,26(1):1-24
We analyze information dissemination in random geometric networks, which consist of n nodes placed uniformly at random in the square ${[0,\sqrt{n}]^{2}}$ . In the corresponding graph two nodes u and v are connected by a (directed) edge, i.e., u is an (incoming) neighbor of v, if and only if the distance between u and v is smaller than the transmission radius assigned to u. In order to study the performance of distributed communication algorithms in such networks, we adopt here the ad-hoc radio communication model with no collision detection mechanism available. In this model the topology of network connections is not known in advance. Also a node v is capable of receiving a message from its neighbor u if u is the only (incoming) neighbor transmitting in a given step. Otherwise a collision occurs prompting interference that is not distinguishable from the background noise in the network. First, we consider networks modeled by random geometric graphs in which all nodes have the same radius ${r > \delta \sqrt{\log n}}$ , where δ is a sufficiently large constant. In such networks, we provide a rigorous study of the classical communication problem of distributed gossiping (all-to-all communication). We examine various scenarios depending on initial local knowledge and capabilities of network nodes. We show that in many cases an asymptotically optimal distributed O(D)-time gossiping is feasible, where D stands for the diameter of the network. Later, we consider networks in which the transmission radii of the nodes vary according to a power law distribution, i.e., any node is assigned a transmission radius r > r min according to probability density function ρ(r) ~ r ?α . More precisely, ${\rho(r) = (\alpha-1)r_{\min}^{\alpha-1} r^{-\alpha}}$ , where ${\alpha \in (1, 3)}$ and ${r_{\min} > \delta \sqrt{\log n}}$ with δ being a large constant. In this case, we develop a simple broadcasting algorithm that runs in time O(log log n) (i.e., O(D)) always surely, and we show that this result is asymptotically optimal. Finally, we consider networks in which any node is assigned a transmission radius r > c according to the probability density function ρ(r) = (α?1)c α-1 r ?α , where α is a constant from the same range as before and c is a constant. In this model the graph is usually not strongly connected, however, there is one giant component with Ω(n) nodes, and there is a directed path from each node of this giant component to every other node in the graph. We assume that the message which has to be disseminated is placed initially in one of the nodes of the giant component, and every node is aware of its own position in ${[0,\sqrt{n}] \times [0,\sqrt{n}]}$ . Then, we show that there exists a randomized algorithm which delivers the broadcast message to all nodes in the network in time O(D . (log log n)2), almost always surely, where D stands for the diameter of the giant component of the graph. One can conclude from our studies that setting the transmission radii of the nodes according to a power law distribution brings clear advantages. In particular, one can design energy efficient radio networks with low average transmission radius, in which broadcasting can be performed exponentially faster than in the (extensively studied) case where all nodes have the uniform low transmission power. 相似文献
290.
Artur J. LemonteSilvia L.P. Ferrari 《Computational statistics & data analysis》2011,55(2):1109-1117
The Birnbaum-Saunders distribution has been used quite effectively to model times to failure for materials subject to fatigue and for modeling lifetime data. In this paper we obtain asymptotic expansions, up to order n−1/2 and under a sequence of Pitman alternatives, for the non-null distribution functions of the likelihood ratio, Wald, score and gradient test statistics in the Birnbaum-Saunders regression model. The asymptotic distributions of all four statistics are obtained for testing a subset of regression parameters and for testing the shape parameter. Monte Carlo simulation is presented in order to compare the finite-sample performance of these tests. We also present two empirical applications. 相似文献