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991.
Jürg Hulliger Luc Dessauges Till A. Samtleben 《Journal of the American Ceramic Society》2006,89(3):1072-1078
Different components forming part of a local configuration of n ≥2 grains constitute a phase system in which the locally available masses define a working point in the corresponding phase diagram. Because the number of configurations can be larger than the number of possible phase diagrams, a basic issue of the single sample concept (SSC) may be addressed by a statistical analysis: is the large phase space of possible compounds efficiently explored by the SSC? In the present study, the compositional distribution functions p ( X E ) were calculated for some of the N components comprising a sample. Broad p ( X E ) distributions were obtained using reasonable assumptions for the distributions describing the grain size and the local coordination number of grains. p ( X E ) functions were calculated both analytically and using a fully numerical procedure. Application of the method to cuprate superconductors revealed that the observed stoichiometries conformed well with the corresponding p ( X E ) distributions. From the present analysis we conclude that the SSC can provide starting compositions for compounds expected to be present in phase systems for given reaction conditions T and p . 相似文献
992.
Eliene Nogueira de Camargo Anderson Oliveira Lobo Maria Margareth da Silva Mario Ueda Edivaldo Egea Garcia Luc Pichon Helfried Reuther Jorge Otubo 《Journal of Materials Engineering and Performance》2011,20(4-5):798-801
NiTi SMA is a promising material in the biomedical area due to its mechanical properties and biocompatibility. However, the nickel in the alloy may cause allergic and toxic reactions and thus limiting its applications. It was evaluated the influence of surface modification in NiTi SMA by nitrogen plasma immersion ion implantation (varying temperatures, and exposure time as follows: <250 °C/2 h, 290 °C/2 h, and 560 °C/1 h) in the amount of nickel released using immersion test in simulated body fluid. The depth of the nitrogen implanted layer increased as the implantation temperature increased resulting in the decrease of nickel release. The sample implanted in high implantation temperature presented 35% of nickel release reduction compared to reference sample. 相似文献
993.
Wagemans Johan; Van Gool Luc; Lamote Christian; Foster David H. 《Canadian Metallurgical Quarterly》2000,26(2):443
Participants judged the affine equivalence of 2 simultaneously presented 4-point patterns. Performance level (d′) varied between 1.5 and 2.7, depending on the information available for solving the correspondence problem (insufficient in Experiment 1a, superfluous in Experiment 1b, and minimal in Experiments 1c, 2a, 2b) and on the exposure time (unlimited in Experiments 1 and 2a and 500 ms in Experiment 2b), but it did not vary much with the complexity of the affine transformation (rotation and slant in Experiment 1 and same plus tilt in Experiment 2). Performance in Experiment 3 was lower with 3-point patterns than with 4-point patterns, whereas blocking the trials according to the affine transformation parameters had little effect. Determining affine shape equivalence with minimal-information displays is based on a fast assessment of qualitatively or quasi-invariant properties such as convexity/concavity, parallelism, and collinearity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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996.
Due to the continuous CMOS transistor scaling requirements, highly doped shallow junctions with improved activation have been widely investigated in recent CMOS technologies. In this scope, sub-melt millisecond laser annealing has been introduced in the integration flows to enhance dopant activation, without any additional detrimental diffusion. This MSA step impacts not only the transistor junction properties, but also the polysilicon gate depletion. This paper is devoted to the study of the MSA influence on boron and germanium co-implanted polysilicon films. A sensitive boron diffusion occurring during the laser anneal step, with or without an initial spike annealing step, has been observed. The activation energy of the boron diffusivity extracted from SIMS profiles in the laser only sequence has been found equal to 4.05 eV. In addition, it was shown that either a high temperature laser anneal sequence or a spike anneal followed by a laser anneal sequence can reach the same activation levels. 相似文献
997.
Product design requires the consideration of geometric models and representations that reflect shape deviations and support tolerance management issues. Computer-Aided Tolerancing (CAT) systems have been developed as simulation tools for modelling the effects of tolerances on digital product simulation. However, geometric variations cannot be addressed efficiently with regard to form deviations. This paper investigates the concepts of Skin Model Shapes, which provide a finite describability and the digital representation of the Skin Model concept, and their unified discrete geometry representation. New contributions to tolerance representation and analysis are presented. Applications and perspectives for CAT systems are highlighted as well. 相似文献
998.
Kenneth J. Mukamal Jemma B. Wilk Mary L. Biggs Majken K. Jensen Joachim H. Ix Jorge R. Kizer Russell P. Tracy Susan J. Zieman Dariush Mozaffarian Bruce M. Psaty David S. Siscovick Luc Djoussé 《Lipids》2013,48(11):1169-1175
We examined common variants in the fatty acid binding protein 4 gene (FABP4) and plasma levels of FABP4 in adults aged 65 and older from the Cardiovascular Health Study. We genotyped rs16909187, rs1054135, rs16909192, rs10808846, rs7018409, rs2290201, and rs6992708 and measured circulating FABP4 levels among 3190 European Americans and 660 African Americans. Among European Americans, the minor alleles of six single nucleotide polymorphisms (SNP) were associated with lower FABP4 levels (all p ≤ 0.01). Among African Americans, the SNP with the lowest minor allele frequency was associated with lower FABP4 levels (p = 0.015). The C-A haplotype of rs16909192 and rs2290201 was associated with lower FABP4 levels in both European Americans (frequency = 16 %; p = 0.001) and African Americans (frequency = 8 %; p = 0.04). The haplotype combined a SNP in the first intron with one in the 3′untranslated region. However, the alleles associated with lower FABP4 levels were associated with higher fasting glucose in meta-analyses from the MAGIC consortium. These results demonstrate associations of common SNP and haplotypes in the FABP4 gene with lower plasma FABP4 but higher fasting glucose levels. 相似文献
999.
Maple syrup is a natural sweetener obtained from the transformation of maple sap collected mostly from sugar maple (Acer saccharum Marsh) in North America. At present, simple physico-chemical tests are used for routine quality control. Inspectors also taste all batches on the market to ensure authenticity. Because of the presence of various aromatic compounds in sap and syrup, intrinsic fluorescence was tested as a means to characterize the physico-chemistry and typicity of maple syrup. Two hundred samples of sap and their corresponding syrup were obtained from various farms in 2003 and 2004. They were analysed by conventional physico-chemical tests and by fluorescence spectroscopy. Two major regions of fluorescence were found, which were mostly the same for sap and syrup. The first one was at 320 nm, excited at 275 nm, and the second one at 460 nm, excited at 360 (syrup) or 370 nm (sap). The first peak diminishes as harvesting season progresses, while the second peak increases, making it possible to predict the harvesting period of syrup from its spectra (r2 = 0.88 in 2003 and 0.81 in 2004). Color of syrup (r2 = 0.91 and 0.88) and bacterial counts in sap (r2 = 0.75 and 0.78) were also predicted from syrup spectra. Results show that sap spectra are related to syrup spectra and could potentially be used as predictor of quality prior to transformation. Discriminant analysis revealed that between 71% and 95% of syrup samples were correctly classified according to the farm of origin in 2003, and between 78% and 100% in 2004. Proximity was not always a factor of explanation of misclassification, suggesting that precise farm location, rather than the broad region of production is the major factor of typicity. 相似文献
1000.
Patrick Richard Luc Oger Jacques Lemaître Liliane Samson Nikolai N. Medvedev 《Granular Matter》1999,1(4):203-211
This article provides a simple method to simulate the transport of a small bead through a static granular medium as a random walk on a network. This kind of displacement is strongly related to the geometry of the porous structure. A way to map the interparticle space is to calculate the Voronoï tessellation of the packing whose edges describe the network of pores of the medium. Then, the calculation of the probabilities to use each bond and a Monte-Carlo method for the choice of them, can simulate the displacement of the sphere. We introduce this technique for the inter-particle percolation of a fine particle through a packing of monosize spheres. We compare our numerical simulation with experiments performed in our laboratory. Then this technique is extended to the surface segregation. For the two kinds of segregation, we study the transverse diffusion and obtain a good agreement with experimental results. That our numerical simulation based on a rigorous geometric analysis of the medium is in agreement with inter-particle percolation and surface segregation experiments shows the importance of the study of the geometry of granular materials. 相似文献