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81.
Liu Ronghao Wells M. Scott Garcia y Garcia Axel 《Nutrient Cycling in Agroecosystems》2020,116(2):195-203
Nutrient Cycling in Agroecosystems - Winter oilseed crops camelina [Camelina sativa (L.) Crantz] and field pennycress (Thlaspi arvense L.) are potential candidates for diversifying the... 相似文献
82.
Dieter Grschl Axel Mayer Michael Schmidt Herbert Meier 《Advanced Synthesis \u0026amp; Catalysis》1995,337(1):379-384
Synthesis of Benzo[b]thioxanthenes Benzo[b]thioxanthenes, heterocyclic compounds related to tetracenes and tetracyclines can be obtained by the reaction of 2H-benzo[b]thiete ( 1 ) and 1,4-naphthoquinones ( 3a–g ). The primary cycloadducts 4a–g undergo an autoxidation process leading to the quinones 6a–g . The dihydroxy compound 4e shows an additional isomerization by a tetrafold H transfer ( 4e → 5e ′). Another preparative route to benzo[b]thioxanthenes makes use of the cycloadditon reaction of 1 and 1,4-epoxynaphthalenes ( 7a–d ). The primary adducts can be transformed to the title compounds by catalytic dehydration processes ( 8a–d → 9a-d ). An alternate regioselective opening of the oxygen bridge can be performed by the action of trimethyliodosilane ( 8a → 10a ). Methylation of 9a furnishes the sulfonium salt 14a which rearranges in a strongly alkaline medium to 16a ; in the presence of oxygen ketone 17a is generated. 相似文献
83.
The exploitation of the underground is currently undergoing a major transformation process. Besides mining, alternative ways of utilization are playing an increasingly important role. These alternative utilizations include the storage of gases, the disposal of radioactive wastes, and the implementation of geothermal storage facilities. In addition, more and more mining operations are being shut down, like the German hard coal mining industry in 2018. But the integrity of closed mines must be ensured in the post-mining phase. In order to capture such large and complex structures efficiently and reliably,new surveying techniques are required. A promising approach is the use of photogrammetric methods to generate three-dimensional models of the cavity. Photogrammetry is currently known mainly from aerial photography. It is conceivable to use such methods for underground applications. In recent years,significant progress has been made in the algorithm-based orientation of unstructured image sets. More powerful computer systems and the growing range of unmanned aerial vehicles could enable partially automated capture. However, a number of problems have to be solved for underground imaging techniques. Unfavorable exposure conditions complicate image alignment. Furthermore, the models must be integrated into existing surveying systems with a sufficiently high degree of accuracy. In order to consider the numerous technical aspects, the development of an integrated capture and evaluation approach is necessary. This could make an important contribution to the monitoring of critical cavities of different commodities. Such an approach would also fit into the current digitization trend in the mining industry and provide new opportunities for ground control in particular. 相似文献
84.
Axel Wiegmann Manuel StavridisMonika Walzel Frank SiewertThomas Zeschke Michael SchulzClemens Elster 《Precision Engineering》2011,35(2):183-190
We present a virtual experiment for the accuracy assessment of the sub-aperture interferometric measurement of a synchrotron mirror involving several thousand sub-aperture topographies. The virtual experiment simulates the measurement process and accounts for the influence of positioning device errors, interferometer errors, non-perfect calibration of machine geometry as well as errors in the interferometer reference. Two principles are considered for reconstructing the form of a test specimen from the conducted sub-aperture topographies, a stitching procedure and a direct measurement method. The virtual experiments are applied to the task of absolute form measurement (including its radius of curvature) of a synchrotron mirror with a length of 30 cm, a width of 4 cm, a maximum curvature of about 44 mm−1 and a peak-to-valley of 5 mm. As a result, reconstruction accuracies can be expected to be in the range of 100 nm when the stitching method is applied, which outperforms the direct measurement method by a factor of about 3. 相似文献
85.
Abhishek Dutta Rahul P. Ekatpure Geraldine J. Heynderickx Axel de Broqueville Guy B. Marin 《Chemical engineering science》2010,65(5):1678-1693
Computational fluid dynamics (CFD) simulations of the hydrodynamic behavior of rotating fluidized beds in static geometry (RFB-SG) are carried out for gas–solid flows. The rotating motion of the reactor bed is induced by the tangential injection of the gas along the circumference of the fluidization chamber. Steep gradients in the gas velocity fields both in radial and tangential direction generate turbulence. The radial and tangential drag forces fluidize the particle bed in both radial and tangential direction.An Eulerian two-fluid model is used. Gas phase turbulence is accounted for by a k–ε model adapted for rotational flows. The RFB-SG simulations provide guidelines for a design and operation with a high efficiency in gas–solid momentum transfer, excellent gas–solid separation and limited solids losses. Hydrodynamic variables like the centrifugal force, the injection pressure, the radial and tangential slip velocities, solids hold-up are calculated for both polymer particles (300 μm, 950 kg/m3, Geldart Group B) and glass beads (70 μm, 2500 kg/m3, Geldart Group A) to allow for a comparison among different fluidization chamber designs. Unstable bed behavior, like slugging and channeling, is also numerically predicted. 相似文献
86.
H. Von Spittler 《Zeitschrift für Jagdwissenschaft》1972,18(2):76-95
Zusammenfassung Nach kurzer referierender Darstellung einiger Anmerkungen über die Nahrungsbiologie, Vermehrungsrate und Besatzermittlung des Fuchses wird der zeitlich-räumliche Verlauf, den die Tollwut in Nordrhein-Westfalen genommen hat, aufgezeigt, wobei herausgestellt wird, daß im wesentlichen die waldreicheren Mittelgebirgslagen des Landes von ihr erfaßt worden sind. An Hand der Streckenergebnisse wird sodann erörtert, in welchem Ausmaß der Fuchsbesatz in den einzelnen betroffenen Kreisen durch die Tollwut reduziert worden ist. Es zeigt sich, daß prozentual der stärkste Rückgang in den Kreisen zu verzeichnen ist, die zuvor die höchsten Strekken aufzuweisen hatten.Sowohl bei den Hasen- als auch bei den Rebhuhnstrecken kommt es in den gleichen Jahren, in denen die Fuchsstrecken abnahmen, zu einer sprunghaften Aufwärtsentwicklung in der Mehrzahl der von der Tollwut heimgesuchten Kreise, wobei sich eine signifikante Proportionalität zwischen Rückgang des Fuchses und Zunahme von Hase und Rebhuhn erkennen läßt.Durch Gegenüberstellung der Streckenergebnisse für Fuchs, Hase und Rebhuhn aus den Kreisen Meschede, Schleiden und Dinslaken wird erläutert, daß die Zunahme der Niederwildstrecken in den Jahren nach Auftreten der Tollwut in erster Linie auf den Rückgang des Fuchses zurückzuführen ist. Günstigere Witterung vermag sich erst sekundär auszuwirken.Auf die Erfordernis einer intensiven Bejagung des Fuchses wird hingewiesen.
Summary The food biology, the reproduction rate of the fox, and the ascertainment of density are briefly presented, after which the time-space development of rabies is discussed; rabies are to be found largely in the forested, sub-alpine mountain areas of the state. As a result of the harvest, the extent to which the fox populations in specific areas are reduced by rabies is examined. It can be shown that the largest percentage decreases occur in areas where the harvest had previously been highest.In the same years that the fox harvest declined, a sudden increase in hare as well as partridge harvests were observed in the majority of rabies-infected areas; a significant correlation between the decrease in foxes and increase in hare and partridge was discerned.Comparison of the harvests of fox, hare und partridge in the districts Meschede, Schleiden and Dinslaken reveals that the increase in small game harvests in the years after the appearance of rabies is primarily a result of the decline in the number of foxes. Favorable weather conditions can have only a secondary effect.The importance of intensive hunting of foxes was emphasized.
Résumé Après un rappel bibliographique à propos de la biologie alimentaire, du taux de reproduction et de l'effectif du Renard, l'évolution dans l'espace et le temps de la Rage en Rhénanie-Westphalie est décrite. Il en ressort que ce sont les régions forestières montagneuses qui sont essentiellement concernées par cette épizootie. L'examen des tableaux du Renard permet par ailleurs de constater que la décimation de cette espèce été proportionellement la plus forte dans les districts où, avant la lutte anti-rabique, les tableauxe étaient les plus élevés.Dans la plupart des secteurs où régnait l'épidémie de Rage, les tableaux en Lièvre et en Perdrix augmentaient brusquement lorsque les tableaux en Renard commençaient à diminuer, ces deux valeurs étant en corrélation négative et significative.L'examen des tableaux du Renard, du Lièvre et de la Perdrix dans des districts de Meschede, Schleiden et Dinslaken montre clairement que l'augmentation des tableaux en petit gibier au cours des années suivant l'apparition de la Rage résulte en premier lieu de la régression du Renard et accessoirement de conditions météorologiques plus favorables.La nécessité d'une chasse intensive du Renard est soulignée.相似文献
87.
Dipl.-Wirt.Inf. Christian Czarnecki Prof. Dr. Axel Winkelmann Prof. Dr. rer.nat./Griechenland habil. Myra Spiliopoulou 《WIRTSCHAFTSINFORMATIK》2013,55(2):83-97
The telecommunication market is experiencing substantial changes. New business models, innovative services, and technologies require reengineering, transformation, and process standardization. Enterprise Architecture Frameworks support the transformation by specifying methods, procedures, and reference models. With the Enhanced Telecom Operation Map (eTOM), the TM Forum offers an international de facto reference process framework, based on specific features and requirements of the telecommunication industry. However, this reference framework only offers a hierarchical collection of processes on different levels of abstraction; a control view in terms of a sequential ordering of tasks and hence a real process flow as well as an end-to-end view on the customer are missing. In this paper, we extend the eTOM reference model by reference process flows, in which we abstract and generalize the knowledge about processes in telecommunication companies. With reference process flows, we aim to assist companies in achieving a structured and transparent re-structuring and re-design of their processes. We demonstrate the applicability and usefulness of our reference process flows in two case studies, and evaluate them by means of criteria for reference model evaluation. Our reference process flows have been accepted as a standard by the TM Forum and published as part of eTOM version 9. We further elaborate on those components of our approach which can be applied outside the telecommunication industry. 相似文献
88.
Axel Schultes 《The Journal of Architecture》2013,18(2):103-111
This paper, which continues the Libeskind/Lampugnani debate in Volume 1 Number 4 (followed up by Robert Maxwell in Volume 2 Number 1), is an edited version of the illustrated lecture delivered in Haifa, Tel-Aviv and Jerusalem in May 1996, and serves as prologue to the Autumn issue of The Journal of Architecture , devoted exclusively to Berlin. 相似文献
89.
Axel Pagán Josep Conde Alberto Ibarz Jordi Pagán 《Food and Bioproducts Processing》2010,88(2-3):77-82
This work studies the variation in the effluent content from the reactor in enzymatic peeling of grapefruits, to determine the loss of soluble solids, reducing sugars and galacturonic acid, the main component from the albedo of the skin to model the solid–liquid transfer in this process. Experiments to study the efficiency of the enzymatic reaction include the effect of the temperature on the kinetics of albedo degradation to find an equation relating both variables and also the activation energy of this process, its value being 36.9 kJ/mol. 相似文献
90.