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排序方式: 共有1944条查询结果,搜索用时 15 毫秒
911.
A new test of normality based on Poincaré inequality is proposed and analyzed. It rests on the characterization of the normal
distribution given by Borovkov and Utev, i.e., a r.v. is normal if and only if its Poincaré constant is equal to its variance. 相似文献
912.
Pierre Muller Pascal Mognol Jean-Yves Hascoet 《Journal of Materials Processing Technology》2013,213(5):685-692
Functionally Graded Materials (FGM) parts are heterogeneous objects with material composition and microstructure that change gradually into the parts. The distinctive feature of FGM structure gives the possibility of selecting the distribution of properties to achieve the desired functions. Today, multi-material parts manufactured with additive manufacturing processes are not functional. To move from these samples to functional and complex parts, it is necessary to have an overall process control. This global approach requires a control of process parameters and an optimal manufacturing strategy. This paper presents a process modeling and a system control to manufacture FGM parts with a direct laser deposition system. This works enable to choose an adapted manufacturing strategy and control process parameters to obtain the required material distribution and the required geometry. 相似文献
913.
Lieven Pandelaers Frederik Verhaeghe Bart Blanpain Patrick Wollants Pascal Gardin 《Metallurgical and Materials Transactions B》2009,40(5):676-684
The dissolution behavior of Ti in liquid Fe has been investigated experimentally and theoretically within the framework of
inclusion formation in steel. In the experimental study, Ti cylinders have been immersed into liquid Fe and, subsequently,
water-quenched. Macroscopic observation of quenched samples shows the initial solidification of an Fe shell around the Ti.
Microstructural analysis of the Fe-Ti interfacial area with a scanning electron microscope equipped with an energy dispersive
X-ray spectrometer reveals that a reaction zone develops in a three-step process: formation of a first liquid eutectic layer
rich in Ti, formation of a second eutectic layer rich in Fe, and then mixing of both layers. The reaction zone grows in thickness
up to 40 pct of the original sample radius and dissolves both parts of the Ti sample and the Fe shell. A simplified, one-dimensional,
implicit finite volume model has been used to describe these phenomena theoretically. Good qualitative agreement is achieved
between experiment and model. The model has been used to estimate the influence of original addition size, preheating, convection,
and superheating on the required melt-back time. 相似文献
914.
Cellular genetic algorithms (cGAs) are a kind of genetic algorithms (GAs) with decentralized population in which interactions among individuals are restricted to close ones. The use of decentralized populations in GAs allows to keep the population diversity for longer, usually resulting in a better exploration of the search space and, therefore, in a better performance of the algorithm. However, it supposes the need of several new parameters that have a major impact on the behavior of the algorithm. In the case of cGAs, these parameters are the population and neighborhood shapes. We propose in this work two innovative cGAs with new adaptive techniques that allow removing the neighborhood and population shape from the algorithm’s configuration. As a result, the new adaptive cGAs are highly competitive (statistically) with all the compared cGAs in terms of the average solutions found in the continuous and combinatorial domains, while finding, in general, the best solutions for the considered problems, and with less computational effort. 相似文献
915.
Tommaso Tamarozzi Pascal Ziegler Peter Eberhard Wim Desmet 《Multibody System Dynamics》2013,30(2):209-219
Contact modeling is an active research area in the field of multibody dynamics. Despite the important research effort of the last decades, two main challenging issues, namely accuracy and speed, are far from being jointly solved. One main issue remains the current lack of model order reduction schemes capable of efficiently treat systems where multiple, a priori unknown, input-output locations are present. This work discusses how a methodology named static modes switching can be extended for its use in gear contact simulation. The method proposes an on-line strategy for the selection of residual attachment modes for accurate local deformation prediction. The applicability of the method is discussed by means of several numerical experiments. The result is an indication that the static modes switching underlying idea can be applied also in case of impulsive phenomena like gear impacts. Moreover, a numerical study on penalty factor values and number of eigenmodes and residual attachment modes shows an interesting relation between these three quantities, the dynamic behavior of the system, and the solution accuracy. Finally, some simulations are performed to compare the adopted model order reduction strategy with a reference nonlinear finite element simulation. 相似文献
916.
917.
Carlos A. Montoya Arturo S. Gomez Jean-Paul Lallès Wolfgang B. Souffrant Stephen Beebe Pascal Leterme 《Food chemistry》2008
Experiments were conducted to study whether phaseolin type could influence proteolysis susceptibility and nutritional value of total bean protein. The DOR-390 bean cultivar was genetically modified to express different phaseolin types (S, T or I). Beans were soaked and autoclaved. A sequential hydrolysis was carried out in vitro with pepsin and pancreatin. Differences in the degree of protein hydrolysis among bean lines started at 30 min and remained until 240 min, with the S bean proteins presenting lower values (P < 0.05). Subsequently, rats were fed with diets containing beans expressing different phaseolin types as the only source of protein for N digestibility and nutritional value determination. No differences (P > 0.05) in ileal protein digestibility and rat growth were observed. In conclusion, the differences in in vitro hydrolysis between bean lines expressing different phaseolin types had no consequences on growth and N retention in rats. 相似文献
918.
919.
Sylvain Dubois Guo P. Bei Christophe Tromas Véronique Gauthier-Brunet Pascal Gadaud 《International Journal of Applied Ceramic Technology》2010,7(6):719-729
Ti3Sn(1−x)AlxC2 MAX phase solid solutions are successfully synthesized from different reactant mixtures. Rietveld refinement allows to carefully characterize their structures and the ocathedra and trigonal prims distortion parameters as a function of the Al content. Mechanical properties of solid solutions are studied from nanoindentation experiments and dynamic resonant method. It is shown that solid solution hardening is not operative in this system. Elastic modulus is found to increase from Ti3SnC2 to Ti3AlC2, and such a result is discussed in terms of Ti–A bond stiffness. 相似文献
920.
Simone Schierle Moritz Helmstädter Dr. Jurema Schmidt Markus Hartmann Maximiliane Horz Astrid Kaiser Lilia Weizel Dr. Pascal Heitel Dr. Anna Proschak Dr. Victor Hernandez-Olmos Prof. Dr. Ewgenij Proschak Dr. Daniel Merk 《ChemMedChem》2020,15(1):50-67
The nuclear farnesoid X receptor (FXR) and the enzyme soluble epoxide hydrolase (sEH) are validated molecular targets to treat metabolic disorders such as non-alcoholic steatohepatitis (NASH). Their simultaneous modulation in vivo has demonstrated a triad of anti-NASH effects and thus may generate synergistic efficacy. Here we report dual FXR activators/sEH inhibitors derived from the anti-asthma drug Zafirlukast. Systematic structural optimization of the scaffold has produced favorable dual potency on FXR and sEH while depleting the original cysteinyl leukotriene receptor antagonism of the lead drug. The resulting polypharmacological activity profile holds promise in the treatment of liver-related metabolic diseases. 相似文献