1,721,222 research outputs found
Ultra-drawing of high-molecular-weight polyethylene cast from solution. IV Effect of annealing/re-crystallization
No full textUltra-drawing of high-molecular-weight polyethylene cast from solution. IV Effect of annealing/re-crystallization
No full textHybrid Composites Based on Polyethylene/Carbon Fibres
No full textThe mechanical properties of high-performance polyethylene (HP-PE) and carbon fibres are to some extent complimentary with respect to toughness, compressive strength and long term properties. Combining both fibres as reinforcing elements In so-called hybride composite structures can result In a unique class of structural materials in terms of strength, stiffness and impact performance. Preliminary results concerning the use of HP-PE and carbon fibres in hybride composite structures, in an epoxy matrix, will be presented emphasizing compressive and impact properties
2H-NMR studies on uniaxially drawn ultrahigh molecular weight polyethylene
No full text2H-NMR expereiments were performed on deuterated, gel-drawn ultrahigh molecular weight polyethylene in order to obtain information about the orientational distribution and the molecular mobility. An increase of the spinlattice relaxation time by about an order of magnitude was observed in comparison to melt crystallized polyethylene indicating high perfection of the fibrillar crystallites. Beside the 2H-NMR resonance for a highly ordered rigid component (orthorhmobic or monoclinic fibrillar crystallites) a highly oriented mobile and a little oriented mobile component was observed. The latter can be assigned to constrained noncrystalline chain segments. saturation-spin echo pulse experiments showed a continuous transition in the T1 time of the oriented components. Variations in the line shape can be explained by a dynamic equilibrium of all-trans conormations an
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Polymers for Electronics and Photonics: conducing ferromagnetic and nonlinear optical properties of polymers
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13C-NMR study of the microstructure of ethylene-vinyl alcohol copolymers
No full textHigh—resolution NMR methods are extremely useful for microstructural
analysis of ethylene copolymers. In the present study ethylene—vinyl
alcohol (E—VOH) copolymers with an increasing content of ethylene were
synthesized and the microstructure was investigated using 13C NNR. The
methylene sequence distributions in these copolymers were investigated.
The occurence of anomalous linkages in E—VOH copolymers i.e. 1,2— and
1,4—diol structures were analyzed. The presence of 1,4—diol structures
could readily be detected in all E—VOH copolymers. The 1,2—diol structure
could be detected in E—VOH copolymers with a low content of ethylene
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