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排序方式: 共有197条查询结果,搜索用时 31 毫秒
31.
Magnetic Resonance Materials in Physics, Biology and Medicine - To evaluate an automatic correction method for velocity offset errors in cardiac 4D-flow acquisitions. Velocity offset correction was...  相似文献   
32.
The hydrogen storage capacity and performance of Ca and K decorated germanene were studied using density functional theory calculation. The Ca and K adatoms were found to be sufficiently bonded to the germanene without clustering at the hollow site. Further investigation has shown an ionic bonding is apparent based on the charge density difference and Bader charge analysis. Upon adsorption of H2 on the decorated germanene, it was found that the Ca and K decorated systems could adsorb 8 and 9 H2 molecules, respectively. The adsorption energies of H2 molecules were within the Van der Waals energy (400–435 meV), suggesting weak physisorption. The charge density profile revealed that the electron of H2 moved toward the adatom decoration without leaving the local region of H2. This suggests that a dipole-dipole interaction was apparent and consistent with the energy range found. Finally, the gravimetric density obtained from the adsorption of H2 on the decorated germanene shows that this material is a potential for H2 storage media.  相似文献   
33.
Journal of Logic, Language and Information - Jc Beall’s off-topic interpretation of Weak Kleene logic offers a logic of ‘true-and-topic’ preservation. However, Nissim Francez has...  相似文献   
34.
This research concerns the problem of the evaluation of the railway infrastructure capacity. It is an important question when railway authorities have to choose between different infrastructure investment projects. We developped independently two heuristic approaches to solve the infrastructure saturation problem. The first is based on a constraint programming model which is solved using a greedy heuristic. The second approach identifies the saturation problem as a unicost set packing problem and its resolution is ensured by an adaption of GRASP metaheuristic. Currently, both resolution techniques are not in competition. The goal is to grasp the resolution ability of the heuristics and to analyse the kind of solutions produced. The Pierrefitte-Gonesse junction has been used as experimental support. A software environment allows to simulate several timetables involving TGV, Inter City and Freight trains.  相似文献   
35.
This paper describes a set of tools that allows a developer to instrument a C/C++ program to log data at run-time and then analyze that data to verify correct behavior. The logging tools provide the developer with a means to log a variety of different data to a variety of different outputs. They also allow for synchronized logging of data from distributed programs. One logging output option is an SQL database. We have developed a set of analysis tools that retrieve data from the database to answer common developer questions. The analysis tools use an interval temporal logic to frame database queries. The data logging tools are fully implemented and performance results are given in this paper. The data analysis tools are currently being tested on data from real NASA applications.  相似文献   
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The present work studies (0001) Al2O3 and (111) Al2MgO4 wetting with pure molten Al by the sessile drop technique from 1073 K to 1473 K (800 °C to 1200 °C) under Ar at PO2 10?15 Pa. Al pure liquid wets a smooth and chemically homogeneous surface of an inert solid, the wetting driving force (t,T) can be readily studied when surface solid roughness increases in the system. Both crystals planes (0001) Al2O3 and (111) Al2MgO4 have crystallographic surfaces with identical O?2 crystalline positions however considering Mg2+ content in Al2MgO4 structure may influence a reactive mode. Kinetic models results under similar experimental conditions show that Al wetting on (0001) Al2O3 is less reactive than (111) Al2MgO4, however at >1273 K (1000 °C) (0001) Al2O3 transformation occurs and a transition of wetting improves. The (111) Al2MgO4 and Al system promotes interface formations that slow its wetting process.  相似文献   
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Summary Staphylococcus aureus strains FRI-100, S6, FRI-137 and FRI 472 were inoculated into milk to study growth and enterotoxin production in homemade yogurts. The yogurt used as starter was progressively weakened by successive inoculations (up to four) in milk to prepare other yogurts in order to study the ability of yogurt microflora to inhibit staphylococci. After elaboration, yogurts were stored at 4 °C, 22 °C, and 37 °C for a maximum of 21 days. Periodically, staphylococcal counts, pH and the production of enterotoxins A, B, C, and D were determined. Enterotoxins were only detected in the last batch. It was concluded that the inhibitory effect of the starter culture is not only due to the decrease of pH, but also to other factors.
Wachstum vonStaphylococcus aureus und Synthese von Enterotoxinen in hausgemachtem Joghurt
Zusammenfassung Stämme vonStaphylococcus aureus wurden in Milch überimpft, um ihr Wachstum und die Enterotoxin-Produktion zu studieren. Der als Joghurt verwendete Starter war durch die fortlaufende Überimpfung (bis zu viermal) in Milch geschwächt, um damit Joghurt herzustellen und seine Fähigkeit zu studieren, Staphylokokken zu hemmen. Nach der Entwicklung wurden die Joghurtproben für 21 Tage bei 4 °C, 22 °C und 37 °C aufbewahrt. Periodisch wurde die Zahl der Staphylokokken, der pH-Wert und die Produktion der Enterotoxine A, B, C und D bestimmt, die allerdings nur in der letzten Partie nachgewiesen wurden konnten. Daraus wurde geschlossen, daß der Hemmeffekt des Starters nicht nur auf die Abnahme des pH-Wertes zuriickzufiihren ist, sondern auch auf andere Faktoren.
  相似文献   
40.
Formula Zero (FZ) is an European project that promotes a zero emissions karts championship based on fuel cell (FC) technology. The project’s objectives are: first, to compete at FZ championship with own FC vehicle, second, to demonstrate that sustainable mobility is possible having zero emissions transports, and third, to take out all the knowledge gained during the development of this project for implanting it in future projects with FC automotive applications. The team has designed and built a kart powered by a stack of PEM 1.2 kW at a first prototype and another prototype powered by a 8 kW stack in a second stage. The goal of the project is to confirm that karts powered by hydrogen and FC are able to compete at velocity races, getting same performance as conventional karts. The difference is that the FC kart is an electric vehicle, with no emissions, no noise, and no vibrations.  相似文献   
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