HAL Id: jpa-00214667
https://hal.archives-ouvertes.fr/jpa-00214667
Submitted on 1 Jan 1971
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
LA FIN DE L’ÉVOLUTION DES ÉTOILES ET LES PULSARS
E. Schatzman
To cite this version:
E. Schatzman. LA FIN DE L’ÉVOLUTION DES ÉTOILES ET LES PULSARS. Journal de Physique
Colloques, 1971, 32 (C5), pp.C5a-31-C5a-31. �10.1051/jphyscol:1971504�. �jpa-00214667�
CRYSTALLIZATION OF CHAIN MOLECULES C5a-31
caily more complex than polyethylene but in view of the greater specificity of the molecules they are capable of providing some detailed information on the central issue of how a crystal layer is to be divided into crystal core and a fold. It could be demonstrated that specific interchain forces, such as the hydrogen bonds reduce the fold length, a point of obvious interest, As the chemical repeat length of these molecules is compara- tively large there will only be a very few such repeats within a lamella. Hence such a lamella will act as a very small crystal, in the case of the presently studied polyhexamethylene adipamide (Nylon 66) consisting only of 4 repeating units. This gives rise to detectable
subsiduary maxima in the diffraction pattern which promises to offer a powerful new diffraction approach to the structure of such lamellae and to the nature of the fold. Certain specific conclusions e. g. that the straight chains traverse the full lamellar thickness and that the chains prefer to fold in the acid group has already been established, hopefully setting the pattern of further developments to follow.
Finally some connections between chain folded crystallization of synthetic polymers and biomolecules are pointed out. Work on the polyamides in particular appears to provide a bridge between these two hitherto disconnected subjects.
LA FIN DE L'EVOLUTION DES ETOILES ET LES PULSARS
E. SCHATZMAN
Resume. -
Une esquisse est donnh de notre connaissance actuelle des dernikres etapes de 1'Bvolution des Btoiles. de I'explosion des supernova1 a la formation des pulsars. De brkves indica- tions sont donnkes sur la structure des Btoiles &neutrons.
Abstract. - A
sketch is given of our knowledge of the last stages of stellar evolution, from supernova1 outbursts to pulsar formation. Brief indications are given on the structure of neutron stars.
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1971504
