摘要:

AbstractIsothermal crystallization of isotactic poly(1‐butene) fractions by calorimetry and microscopy was studied for a range of molecular weights from 96 000 to 964000. An Avrami exponent of 2 was found indicating a two‐dimensional growth rate of the crystal, following a predetermined nucleation mode, proving that such an exponent is independent of both temperature and molecular weight. The temperature and molecular weight dependence of the growth rate of spherulites and overall crystallization rates was analyzed by means of the theoretical expression given by Hoffman and Lauritzen. The product of the lateral and basal surface free energies of the crystallites, σ·σe, increases with molecular weight and approaches its limiting values when a certain molecular weight is at

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830321

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractAn X‐ray structure analysis was performed on single crystals of the cycloalkane (CH2)36. The lattice belongs to the space groupAaand is arranged in layers. The unit cell has the dimensions α = 1,033 nm,b= 0,824 nm,c= 4,22 nm, β = 107, 1° and contains four molecules. The molecules consist of two stretched stems which are linked by sharp folds at each end. The folds have the conformation …t(g g t g g) t… lying parallel to theb‐axis. Raman measurements suggest that the stems are slightly twisted. A comparison of the homologous series (CH2)n,n= 36, 48, 60, and 72 using X‐ray powder methods showed that the (CH2)36‐structure, including the fold conformation, is also representative for the longer chai

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830322

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY

摘要:

AbstractThe small‐angle X‐ray scattering ofL‐leucine dehydrogenase (EC 1.4.1.9) fromBacillus sphaericusin 0,2 M sodium phosphate buffer (pH 7,28) was investigated. The following molecular parameters were determined: radius of gyration, as 50,8 Å from the Guinier plot and 48,5 Å from the distance distribution function; molecular weight, as 267 000; volume, as 623 000 Å3; and degree of hydration, as 0,95 g H2O/g of enzyme. By comparing the observed scattering curve with those calculated with a number of models, a hollow cylinder with 47,0 Å of outer radius, 10,3 Å of inner radius and 119,0 Å of length was proposed as a most plausible model for

ISSN:0025-116X    

DOI:10.1002/macp.1982.021830323

出版商:Hüthig&Wepf Verlag    

年代:1982

数据来源: WILEY