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排序方式: 共有236条查询结果,搜索用时 31 毫秒
61.
JPC – Journal of Planar Chromatography – Modern TLC - Thin layer chromatography with flame-ionization detection has been used for analysis of oligosaccharides. We report preliminary... 相似文献
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63.
Journal of Solid State Electrochemistry - 相似文献
64.
Joachim Mohn Christina Biasi Samuel Bodé Pascal Boeckx Paul J. Brewer Sarah Eggleston Heike Geilmann Myriam Guillevic Jan Kaiser Kristýna Kantnerová Heiko Moossen Joanna Müller Mayuko Nakagawa Ruth Pearce Isabell von Rein David Steger Sakae Toyoda Wolfgang Wanek Sarah K. Wexler Naohiro Yoshida Longfei Yu 《Rapid communications in mass spectrometry : RCM》2022,36(13):e9296
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66.
We present a novel semi-parametric model for two-sample survival data, and an estimation method with a simple, closed-form solution. We study analytically the asymptotics of the estimators, and conduct a small simulation study. 相似文献
67.
We present a method for constructing families of isospectral systems, using linear representations of finite groups. We focus
on quantum graphs, for which we give a complete treatment. However, the method presented can be applied to other systems such
as manifolds and two-dimensional drums. This is demonstrated by reproducing some known isospectral drums, and new examples
are obtained as well. In particular, Sunada’s method (Ann. Math. 121, 169–186, 1985) is a special case of the one presented. 相似文献
68.
Non-classical negations may fail to be contradictory-forming operators in more than one way, and they often fail also to respect fundamental meta-logical properties such as the replacement property. Such drawbacks are witnessed by intricate semantics and proof systems, whose philosophical interpretations and computational properties are found wanting. In this paper we investigate congruential non-classical negations that live inside very natural systems of normal modal logics over complete distributive lattices; these logics are further enriched by adjustment connectives that may be used for handling reasoning under uncertainty caused by inconsistency or undeterminedness. Using such straightforward semantics, we study the classes of frames characterized by seriality, reflexivity, functionality, symmetry, transitivity, and some combinations thereof, and discuss what they reveal about sub-classical properties of negation. To the logics thereby characterized we apply a general mechanism that allows one to endow them with analytic ordinary sequent systems, most of which are even cut-free. We also investigate the exact circumstances that allow for classical negation to be explicitly defined inside our logics. 相似文献
69.
Glass transition temperature (Tg) of submicron-sized, carboxylated polymer particles dispersed in aqueous media, which were prepared by emulsion copolymerization of styrene, iso-butyl methacrylate, or methyl methacrylate with methacrylic acid, was measured at alkali or acidic pH region with a power compensation-type high sensitive differential scanning calorimeter. The Tg of relatively hydrophilic polymer particles was obviously decreased by the neutralization of the carboxyl groups with KOH, whereas that of hydrophobic polymer particles was not changed though water was absorbed therein. These results indicate that water absorption state, which means not only the amount of water absorption but also the heterogeneity of the ionized carboxylated polymer particles, markedly depends on the hydrophilicity of their base polymers. This strongly supports the formation mechanism of multihollow particles by the stepwise alkali/acid or the alkali/cooling treatments of carboxylated polymer particles proposed by the authors.Part CCLXIX of the series, “Studies on Suspension and Emulsion.” 相似文献
70.
Mayuko Ori 《Tetrahedron》2005,61(8):2075-2104
An efficient methodology for the synthesis of 2,2,3-trisubstituted tetrahydroquinolines has been developed, which involves the triphenylphosphine-CCl4-mediated stereospecific rearrangement of α,α-disubstituted indoline-2-methanols 15 to 2,2,3-trisubstituted tetrahydroquinolines 26. The rearrangement precursors 15 are readily prepared by the diastereoselective Grignard addition to 2-acylindolines 13. The total syntheses of (+)-benzastatin E (1) and natural virantmycin (2a) were accomplished utilizing this methodology. This rearrangement reaction might afford some chemical precedent for the biogenetic pathway of the benzastatin family. 相似文献