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51.
Proton nuclear magnetic resonance (NMR) spin-spin relaxation measurements were made on three commercial-grade polyethylenes in the melt state, free of solvent. All samples exhibit a three-component relaxation behavior, with components being assigned to amorphous low-molecular weight material (non-network fraction), amorphous entangled network fraction, and an ordered or high-segmental-density fraction, in order of decreasing relaxation times. Sample thermal history is shown to have a considerable effect on the overall relaxation behavior, and therefore on the relative amounts of each of the three components in the melt. An adequate thermal treatment of samples produces an equilibrium melt with invariant composition of the three fractions. The effects of thermal history on the relative amount of high-segment-density regions in the melt parallels its effect on the fraction of crystalline material in the solid polymer. These results are evidence for the persistence of ordered regions in polyethylene at temperatures well above the crystalline melting point of the polymer. We further comment on the nature of the two slower relaxing components and present examples of how the components manifest themselves in other polymer characterization techniques. © 1992 John Wiley & Sons, Inc. 相似文献
52.
Clara Löh 《Mathematische Zeitschrift》2006,253(1):197-218
Measure homology is a variation of singular homology designed by Thurston in his discussion of simplicial volume. Zastrow
and Hansen showed independently that singular homology (with real coefficients) and measure homology coincide algebraically
on the category of CW-complexes. It is the aim of this paper to prove that this isomorphism is isometric with respect to the ℓ1-seminorm on singular homology and the seminorm on measure homology induced by the total variation. This, in particular, implies
that one can calculate the simplicial volume via measure homology – as already claimed by Thurston. For example, measure homology
can be used to prove Gromov's proportionality principle of simplicial volume. 相似文献
53.
Ulrike Tillmann 《K-Theory》1992,6(5):457-463
Karoubi's relative Chern character is constructed as a chain map factoring through Lie algebra chains.This is part of the author's doctoral thesis, Stanford University 1990. 相似文献
54.
M. Larsen 《K-Theory》1995,9(2):173-198
We describe an approach to computing cyclic homology suited to ground rings of characteristicp or mixed characteristic. We illustrate the method by computing HC for coordinate rings of affine plane curves and for maximal orders of semisimple algebras.Partially supported by NSF Grant No. DMS-8807203 and NSA Grant No. MDA 904-92-H-3026. 相似文献
55.
Dae- Woong Lee 《数学物理学报(B辑英文版)》2002,(1)
1 IntroductiouLet G and Z be an abelian group and the set Of all integers respectively And letC = (C., ft,', I') denote an inverse system of chain complexes C. and chain maPS I..1: Cv, -Ct,7 5 T' indexed by a directed set r. Strong homology groups HP(C) of the inverse systemC were defilled by J. T. Lisica and S. Mardedie[n. Using the ANRresOlution[9'l1I, algebraictopolOgists defined the strong homology group HP(X; G) of a topological space X with coefficient8 in G and gave exMPl… 相似文献
56.
Max Karoubi 《K-Theory》1994,8(2):153-211
Résumé L'objet de cet article est de montrer comment laK-théorie multiplicative peut être utilisée pour définir de nouvelles classes caractéristiques secondaires de fibrés vectoriels munis de structures supplémentaires, dans des contextes géométriques variés. On y développe des exemples reliés à des travaux antérieurs divers.
The purpose of this paper is to show how multiplicativeK-theory may be used to define new secondary characteristic classes for vector bundles with additional structures, in various geometrical contexts. Many examples are developed which are related to previous works.相似文献
57.
Homology Stability for Unitary Groups II 总被引:1,自引:0,他引:1
B. Mirzaii 《K-Theory》2005,36(3-4):305-326
In this paper, the homology stability problem for hyperbolic unitary groups over a local ring with an infinite residue field
is studied. We obtain a much better range of homology stability compared to the results existing in the literature. An application
of our results is given. 相似文献
58.
建立了单光子光化烧孔的三能级模型,求解了反映质子转位变构机制的速率方程组,推导了成孔过程的动力学特性,获得了可与实验进行比较的解析解.用时域和频域两种方法测量了THP/PMMA和TMP/PMMA薄膜样品光谱烧孔的动力学过程,得到与理论分析一致的规律,并测得了有效成孔速率和成孔时间等参数.这些参数对于评价频域光存贮材料性能有一定意义. 相似文献
59.
We apply the theory of signature invariants of links in rational homology spheres to covering links of homology boundary links. From patterns and Seifert matrices of homology boundary links, we derive an explicit formula to compute signature invariants of their covering links. Using the formula, we produce fused boundary links that are positive mutants of ribbon links but are not concordant to boundary links. We also show that for any finite collection of patterns, there are homology boundary links that are not concordant to any homology boundary links admitting a pattern in the collection.
60.
Liangxia WAN 《Frontiers of Mathematics in China》2023,18(1):1
The alternating links give a classical class of links. They play an important role in Knot Theory. Ozsváth and Szabó introduced a quasi-alternating link which is a generalization of an alternating link. In this paper we review some results of alternating links and quasi-alternating links on the Jones polynomial and the Khovanov homology. Moreover, we introduce a long pass link. Several problems worthy of further study are provided. 相似文献