排序方式: 共有19条查询结果,搜索用时 15 毫秒
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Thermostable polymers and, more particularly, thermostable fibers and films are becoming more and more important as the demands of space-age technology increase. In the preparation of thermostable fibers having good tensile strengths and practical utility the processibility of the polymer is of great importance. Aromatic polyamides meet the two most important requirements: a high degree of thermal stability and an ease of preparation as viscous solutions that can be spun into fibers or cast into films. 相似文献
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U. Amaldi G. Cocconi A.N. Diddens R.W. Dobinson J. Dorenbosch W. Duinker D. Gustavson J. Meyer K. Potter A.M. Wetherell A. Baroncelli C. Bosio 《Physics letters. [Part B]》1977,66(4):390-394
The real part of the proton proton elastic scattering amplitude has been determined from its interference with the Coulomb amplitude at total centre-of-mass energies up to 62 GeV. The observed steady increase of ? with energy indicates that the total proton proton cross section continues to increase well beyond this energy. 相似文献
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Frank Dobinson J. Preston 《Journal of polymer science. Part A, Polymer chemistry》1966,4(9):2093-2105
Symmetrical diamines, containing preformed carbonamide linkages, were prepared by reacting nitrobenzoyl chlorides with aromatic diamines and reducing the dinitro intermediates. The diamines were polymerized with aromatic diacid chlorides to give wholly aromatic ordered copolyamides of exceptionally high thermal stability. Ordered diamines were prepared containing only phenylene units as the aromatic portion, and others containing phenylene and naphthylene or biphenylene groups. Low-temperature solution polymerization of these diamines with isophthaloyl chloride, 4,4′-bibenzoyl chloride, or 2,6-naphthalenedicarbonyl chloride, gave thirteen ordered copolyamides, each containing a naphthylene and/or biphenylene group in its repeating unit. Differential thermal analyses and thermogravimetric analyses showed these polymers to have melting points or decomposition temperatures of from 420 to over 500°C. Films of one of the polymers had a breakdown voltage of 3000 v./mil at 180°C. Fibers of the same composition had tenacities of up to 8 g/den.; a 5.5 g/den. sample retained 85% of its tenacity after 17 hr. at 300°C. and 21% after 9 days. 相似文献
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U. Amaldi W. Bartel G. Cocconi A.N. Diddens Z. Dimcovski R.W. Dobinson P. Duinker A.M. Thorndike A.M. Wetherell G. Bellettini P.L. Braccini R. Castaldi T. Del Prete P. Laurelli G. Sanguinetti M. Valdata A. Baroncelli G. Matthiae R. Thun 《Physics letters. [Part B]》1975,58(2):206-212
Data obtained from p-p collisions at centre-of-mass energies between 31 and 63 GeV are presented on correlations between momentum analysed forward π?, K? and and charged particles observed in an omnidirectional hodoscope. The data show that significant correlations are present over the whole rapidity range for all three types of negative particles. The dependence on various kinematic variables suggests a cluster mechanism for the production of particles. In this picture, pions would be produced in clusters emitted in the fragmentation region while K? and emanate from non-leading clusters. 相似文献
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