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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 5 (1969), S. 213-253 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We calculate the effects of hyperons and resonance particles on the vibrations of neutron stars. Vibrating neutron stars can store large amounts of energy in their vibrations; the interaction of the vibrations with the atmosphere would produce electromagnetic radiation. If any process damps out the vibrations rapidly on an astronomical time scale (∼ 1000 years) then vibrating neutron stars are not likely to be found. Previous work indicates that radiation by a neutrino URCA process (N+N→P+N+e −+ $$\bar v_3 $$ ) does not rapidly damp many of the neutron star models. Some neutron stars are predicted to contain massive baryons; here we study thermal damping by nonequilibrium reactions involving these baryons. During vibrations the thermodynamic equilibrium state is changed and particle reactions attempt to restore equilibrium. If the reaction rates per particle are very rapid or slow compared to the frequency of vibration the system follows almost the same pressure-volume curve through both parts of the gas cycle, and very little work is done. In the intermediate case, when reaction rates are comparable to the frequency, damping is rapid. We find that the reaction rates for weak interactions such asN+N↔P+Σ− (the Σ− is the first hyperon to appear with increasing density in degenerate neutron star matter) are of the right magnitude to cause rapid damping. If there is a hyperon region in the star then it cannot sustain vibrations. We also consider the much faster (and hence less important) processN+N↔P+Δ−.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 5 (1969), S. 259-271 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract An equation of state for cold matter above white dwarf densities is evaluated. The gas is considered to be a mixture of degenerate neutrons, protons and electrons combined with nuclei of one type (that is only oneA andZ value). We derive the equilibrium equations for the mixture and calculate the number densities as well as theA andZ of the nucleus. Finally we calculate an equation of state, which smoothly goes over to that of a neutron, proton electron gas mixture at a density of ∼5×1013 g/cm3.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 5 (1969), S. 113-125 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract In this paper, pulsating white dwarfs are treated via general relativity. Numerical integration of Einstein's equations was used to find equilibrium white dwarfs models and the fundamental periods of small oscillations about these equilibrium models. In these calculations account was taken of coulomb, Thomas-Fermi, and exchange interactions as well as ion zero point energies. It is shown that general relativity makes not just a quantitative difference in the results but a qualitative differences; pure C12 models which are stable in Newtonian mechanics can be unstable against collapse (at a central density of 3×1010 g/cm3) when general relativity is taken into account. The collapsing model may become a neutron star or may continue towards the Schwarzschild radius. More realistic white dwarf models with carbon burning products at the center, also were studied. For these models, the density at which the star becomes unstable against collapse due to electron capture (3×109 g/cm3) was found to be lower than the density at which general relativistic instability occurs.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Genetica 37 (1966), S. 1-6 
    ISSN: 1573-6857
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Crossing over frequency was determined for five marked regions covering most of a chromosome arm. The results of a 12th backcross were compared with previously published results from the noninbred f1. Exchange frequency increased significantly following inbreeding. Chiasma interference remained positieve, but was somewhat less intense in b12.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Astrophysics and space science 1 (1968), S. 129-146 
    ISSN: 1572-946X
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The implications of recent studies of the dynamics of the cores of highly evolved massive stars are considered with regard to the general problems of nucleosynthesis. The typical conditions estimated for these models are shown to be very promising for the process of element synthesis by neutron capture on a fast time scale (ther-process ofBurbidge et al., 1957).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 259-272 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: In order to study structure-tissue reactivity relationships and ultimately develop a less necrotizing adhesive, this laboratory undertook a study of the synthesis and degradation of the homologous series of α-cyanoacrylate monomers and polymers. A method for synthesizing high purity cyanoacrylates and some of their chemical and physical properties and presented. In vitro kinetics studies under heterotgeneous and homogeneous conditions indicate that cyanoacrylate polymers degrade by hydrolytic scission of the polymer chain. The products resulting from such a scission are formaldehyde (positively identified by derivative formation) and ultimately and alkyl cyanoacetate. As the homologous series is ascended, the rate of degradation under neutral conditions decreases. In homogeneous solutions, under alkaline conditions, the ràte of degradation is considerably higher than under neutral conditions and the rates obtained with the methyl to the butyl derivative are of the same order. Aproposed mechanism of degradation is presented. Medical evaluation has indicated that as the homologous series is ascended, the greater the tissue tolerance to the monomers and polymers. The relevance of the results of the in vitro studies to this medical finding is presented.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 11 (1969), S. 967-985 
    ISSN: 0006-3592
    Schlagwort(e): Chemistry ; Biochemistry and Biotechnology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: A description is given of the design and operation of high-power magnetic drives developed to enable shaft seals and glands to be dispensed within deepculture vessels, in tissue homogenizers, and in mixing and filling processes where sterility is essential. The drives operate at speeds of 300 to 2000 rpm in volumes of 300 1. to 10 ml with clearances up to 16 mm between the pole faces of the magnets.Two types of drive are described, one in which the driving and driven magnets form an integral unit on the lid of a vessel: such vessels are used for transporting material. To intiate stirring, it is only necessary to connect a motor directly, or through a cable-drive, to the magnetic-drive assembly. In the other type of unit the driving magnet is attached permanently to the driving motor. Locating pins on the base of the motor and corresponding sockets on the lid of the vessel ensure that when the motor is in position, the driving and driven magnets are located correctly in relation to one another.The design of these drives is based on the use of multipole, ceramic magnets. The advantages of their use in such units, compared with metal magnets, are discussed. Earlier magnetic drives are also discussed and explanations offered for the difficulties formerly met in scaling up.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 10 (1966), S. 1214-1214 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 4025-4028 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    ISSN: 0095-9898
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Cells of the germinal layer of mouse esophageal epithelium were used for quantitative assessment of the spatial distribution of proliferating cells. In tritiated thymidine autoradiographs the nonsynthesizing cells between synthesizing (or dividing) cells were counted, rather than counting the dividing cells in pre-established grid units. Dividing and DNA-synthesizing cells are almost random in spatial distribution, but there is an excess of labeled or dividing cells immediately adjacent to one another over what would be expected if the spatial distribution were random. Two possible explanations for the excess of adjacent proliferating cells are suggested: (a) direct cellular interaction or local humoral influences, and (b) phasing of adjacent cells which have a common line of descent.
    Zusätzliches Material: 2 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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