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排序方式: 共有501条查询结果,搜索用时 15 毫秒
31.
Christiane L. Ojaimi Julieta A. Ferreira Adilson L. Chinelatto Raphael E. P. Salem Adriana S. A. Chinelatto Eliria M. J. A. Pallone 《International Journal of Applied Ceramic Technology》2020,17(4):1619-1628
Composites of Al2O3/ZrO2 (containing 25, 50, and 75 vol% ZrO2) were prepared by mixing Al2O3 and ZrO2 suspensions. The microstructural control via two-step sintering (TSS) was the main objective of this work. For this purpose, different sintering curves were constructed, aiming to achieve the best temperature combination for the sintering steps that provides higher density and finer microstructure. The results were compared with single-step sintering (SSS). Furthermore, microhardness and fracture toughness were measured for the best TSS specimens under each composition. The results showed that the high densities were obtained, and the reduction of grain size was greater than 40% for two-step sintered specimens, compared to SSS ones. Consequently, microhardness values increased. However, fracture toughness values remained unchanged. 相似文献
32.
城市增长是未来几个世纪备受关注的问题。为了保证城市可持续发展,有必要对城市的发展进行监控,但预测城市的发展趋势需要一些空间信息的支持、卫星图像能够提供可靠的信息用来评定城市增长的不同状态,而预测未来的建设区段则更加重要。本文构建了相互作用模型(interaction models),或者更精确地说叫潜力模型(potential model),以确定城市空间的扩展方向。该模型被运用于法国斯特拉斯堡地区的分析,采用了两张遥感数据影像,一张用于模型处理,一张用于检验结果。另外,模型还运用GIS技术以提高准确度,同时还考虑到了交通网络。 相似文献
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News
Fifth International Deer Biology Congress 相似文献35.
36.
Carrasco C Rosu F Gabelica V Houssier C De Pauw E Garbay-Jaureguiberry C Roques B Wilson WD Chaires JB Waring MJ Bailly C 《Chembiochem : a European journal of chemical biology》2002,3(12):1235-1241
The structural selectivity of the DNA-binding antitumor drug ditercalinium was investigated by competition dialysis with a series of nineteen different DNA substrates. The 7H-pyridocarbazole dimer was found to bind to double-stranded DNA with a preference for GC-rich species but can in addition form stable complexes with triplex and quadruplex structures. The preferential interaction of the drug with four-stranded DNA structures was independently confirmed by electrospray mass spectrometry and a detailed analysis of the binding reaction was performed by surface plasmon resonance (SPR) spectroscopy. The BIAcore SPR study showed that the kinetic parameters for the interaction of ditercalinium with the human telomeric quadruplex sequence are comparable to those measured with a duplex sequence. Slow association and dissociation were observed with both the quadruplex and duplex structures. The newly discovered preferential binding of ditercalinium to the antiparallel quadruplex sequence d(AG(3)[T(2)AG(3)](3)) provides new perspectives for the design of drugs that can bind to human telomeres. 相似文献
37.
Shigeki Akiyama Frdrique Bassino Christiane Frougny 《Information and Computation》2005,201(2):199-215
Non-standard number representation has proved to be useful in the speed-up of some algorithms, and in the modelization of solids called quasicrystals. Using tools from automata theory we study the set of β-integers, that is, the set of real numbers which have a zero fractional part when expanded in a real base β, for a given β > 1. In particular, when β is a Pisot number — like the golden mean —, the set is a Meyer set, which implies that there exists a finite set F (which depends only on β) such that . Such a finite set F, even of minimal size, is not uniquely determined.In this paper we give a method to construct the sets F and an algorithm, whose complexity is exponential in time and space, to minimize their size. We also give a finite transducer that performs the decomposition of the elements of as a sum belonging to . 相似文献
38.
Hoppe Christiane M.; Kagan Spencer M.; Zahn G. Lawrence 《Canadian Metallurgical Quarterly》1977,13(6):591
32 Anglo-American and Mexican-American boys and girls selected for their extreme field independence or dependence (Man-in-the Frame box, adapted from the rod-and-frame test) interacted with their mothers in 3 role plays designed to provoke conflict over issues of maternal authority and children's independence. The mother–child interactions were recorded, transcribed, and content analyzed. Anglo-American children more often than Mexican-American children entered and persisted in direct conflict with their mothers as indicated by a number of variables such as disagreement and justification of their own will. There was some tendency for Mexican-American mothers to ask fewer questions and to assert their own will more than Anglo-American mothers. Field independence among boys, but field dependence among girls, was associated with more assertive behaviors. Mothers of field-independent children used a somewhat more elaborate verbal code. The study supports hypothesized cultural differences in mother–child interaction patterns, but fails to support the presumed socialization antecedents of field dependence and the cross-sex generality of its correlates. (31 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
39.
Timmel CR Henbest KB 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2004,362(1825):2573-2589
This paper reviews the latest developments in the field of spin chemistry with a particular focus on the effects of weak static and/or oscillating magnetic fields (typically smaller than the average hyperfine coupling) on radical recombination reactions. Anisotropic magnetic field effects and their significance in the debate about potential mechanisms controlling magnetoreception in birds are discussed. 相似文献
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