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  • Polymer and Materials Science  (8)
  • General Chemistry  (4)
  • Brassicaceae  (2)
  • 1
    ISSN: 1432-2242
    Keywords: Thlaspi ; Subtribe Thlaspidinae ; Brassicaceae ; Chloroplast DNA ; Restriction-site variation ; Molecular systematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chloroplast DNA restriction-site variation was analyzed in 30 accessions representing 20 species from the major lineages in Thlaspi s.l. (previously described as genera by Meyer 1973, 1979) and allied genera from the subtribe Thlaspidinae (Peltaria, Teesdalia, Cochlearia, Ionopsidium, Aethionema). A total of 161 variable restriction sites were detected. Phylogenetic analyses indicated a division of Thlaspi s.l. into three groups consistent with Meyer's genera Thlaspi s. str., Microthlaspi and Noccaea/Raparia. The genus Thlaspi s.l. as currently described proved to be paraphyletic because one of its major lineages, i.e. Thlaspi s. str., appeared to be more closely related to other genera (Peltaria, Teesdalia) than to the remaining lineages of Thlaspi s.l., i.e. Noccaea/Raparia and Microthlaspi. Sequence divergence values (100 x p) between the Thlaspi s.l. lineages were similar to values between these groups and related genera (Teesdalia, Peltaria), respectively. Chloroplast DNA variation was also used to assess subtribal classification of the genera studied. The cpDNA data were inconsistent with the controversial taxonomic classifications based on morphology. The molecular data would suggest that (1) the subtribe Thlaspidinae, as traditionally described, is not monophyletic; (2) the Thlaspidinae should be reduced to a group consisting of Thlaspi s. str., Peltaria, Teesdalia, Microthlaspi, Noccaea/Raparia, and that Aethionema should be excluded from the Thlaspidinae; and (3) Cochlearia and Ionopsidium represent the subtribe Cochleariinae.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 4 (1973), S. 81-85 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Residual stresses in the surface of gas and bath nitrided steel specimens. Residual stresses in the steels Ck 45, 34 Cr 4, 34 CrAl 6, and Ck 15 were measured by X-ray diffraction. Cylindrical specimens of the heat-treated steels were nitrided in ammonia-gas and in a Tenifer®-salt- bath. The course of residual stresses of Ith order was determined by removing thin layers. With the carbon steel Ck 15 ist shown the effect of tempering on residual stresses in bath-nitrided and quenched specimens.
    Notes: Es wird über röntgenographische Spannungsmessungen an den Stählen Ck 45, 34 Cr 4, 34 Cr Al 6 und Ck 15 berichtet. Zylindrische Proben aus den Vergütungsstählen wurden im Ammoniak-Gasstrom und im Tenifer®-Salzbad nitriert und der Verlauf der Eigenspannungen I. Art durch Abtragen und mehrfaches Messen bestimmt. Am Beispiel des Kohlenstoffstahles Ck 15 wird gezeigt, wie sich eine thermische Nachbehandlung auf die Eigenspannungen badnitrierter und nach der Behandlung in Wasser abgeschreckter Proben aus diesem Werkstoff auswirkt.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 11 (1980), S. 68-72 
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Internal Stresses due to Rolling with and without SlipInternal stresses have been measured in specimens of roller bearing steel 100 Cr 6 with X-ray technique. The course of the internal stresses has been determined in dependence of the number of load cycles and slip. It is shown, that the internal stresses strongly depend on the slip magnitude.
    Notes: Mit Hilfe der röntgenographischen Eigenspannungsmessung wurde die Eigenspannungsausbildung in Proben aus 100 Cr 6 in Abhängigkeit von Überrollungszahl und Schlupf ermittelt. Es zeigt sich, daß die Eigenspannungsausbildung sehr stark vom Makroschlupf bestimmt wird.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0933-5137
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Residual Stress Measurements on Differently Decarburized, Shot Peened and Cyclic Torsional Loaded Specimens of a Spring SteelIn addition to previous fatigue tests with the spring material 55 Cr 3, X-ray residual stress measurements were carried out on differently decarburized, shot peened and cyclic torsional loaded specimens. It was shown that longer duration of decarburization leads to higher residual tensile stress in the surface zone for not peened specimens. Shot peening, however, effects almost equal residual compressive stresses in the surface zone in spite of different starting conditions, with a slight decrease for specimens with a long duration of decarburization, which corresponds to the results of the fatigue tests.By cyclic torsional loading with mean stress the residual compressive stresses due to shot peening are diminished in the axial and circumferential directions. A main stress system is now to be found with an angle of 45° to axis, whereas the residual stresses in the s̰1-(tensile direction) retain their values, those in the s̰2-(compressive) direction are decreased distinctly.
    Notes: Im Rahmen eines von der Arbeitsgemeinschaft Industrieller Forschungsvereinigungen geförderten Forschungsvorhabens wurden zahlreiche Torsionsschwellversuche an Rundproben mit 14 mm ∅ aus dem Werkstoff 55 Cr 3 durchgeführt. Zur Interpretation der Schwingfestigkeitsergebnisse wurden Härte- und Kohlenstoffverlaufskurven in der Randschicht der einzelnen Probenvarianten aufgenommen und metallographische Untersuchungen vorgenommen [1].Um die Aussagefähigkeit der Schwingfestigkeitsergebnisse zu verbessern, wurde anschließend ein reduziertes Programm zur Untersuchung der Eigenspannungszustände der wesentlichen Abkohlungsvarianten an Proben der gleichen Charge durchgeführt. Über die Ergebnisse dieser Eigenspannungsmessungen wird im folgenden ausführlich berichtet, wobei zunächst einleitend die wichtigsten Parameter und Ergebnisse des Forschungsvorhabens zusammengefaßt dargestellt werden.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1615-6110
    Keywords: Brassicaceae ; Lepidium ; sect.Cardamon ; Lepiocardamon ; Lepia ; cpDNA ; restriction site variation ; systematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chloroplast DNA restriction site variation was examined amongLepidium taxa usually classified in sects.Lepia, Lepiocardamon andCardamon. By using 15 restriction endonucleases, filter hybridization experiments, and comparative mapping procedures, a total of 119 variable restriction sites was detected. Of these, 56 were phylogenetically informative and were used in a cladistic analysis. The resulting phylogenetic tree agrees with results derived from morphology, isozyme electrophoresis and the analysis of glucosinolates. The data suggest: 1) The recognition of sect.Lepia, and 2) that sect.Lepiocardamon has close relationships to sect.Cardamon and that both should be amalgamated. Low rates of interspecific chloroplast DNA sequence divergence in sect.Lepia correlated well with morphological data and isoelectric focusing analysis of Rubisco, suggesting that taxa of sect.Lepia are closely related and most likely have diversified recently.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0021-9304
    Keywords: collagen fibrils ; apatitic crystals ; orientation ; X-ray diffraction ; polarized optical microscopy ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: X-ray diffraction and polarized optical microscopy investigations were carried out on thin sections of rabbit tibia in order to study the morphological organization of the structural components of this tissue, which often is utilized to test bone response to implants. In the optical microscope, the lateral face as well as the lateral portion of the caudal face exhibit a lamellar structure with an alternation of dark and bright lamellae running parallel to the long axis of the tibia. In contrast, both in the medial face and in the medial portion of the caudal face there are numerous osteonic structures. In spite of the complexity of this morphological organization, the results of small- and high-angle X-ray diffraction analyses indicate that the structural relationship between collagen fibrils and inorganic crystals is quite similar to that observed in single osteons and allows evaluation of the orientation of the two main structural components. Both collagen fibrils and apatitic crystallites are preferentially oriented parallel to the long axis of the tibia. The degree of orientation is greater in the thickness than in the plane of the lamellae, suggesting that collagen fibrils and inorganic crystallites lie preferentially in the plane of the lamellae, where they follow an oblique course. The degree of orientation of the apatitic crystallites is higher in the lateral face than in the medial and caudal faces, in agreement with the optical microscopic images. The results provide information that must be taken into account when evaluating the structural modifications of bone due to the insertion of a prosthetic device. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 41, 289-295, 1998.
    Additional Material: 5 Ill.
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  • 7
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The time course of the small angle scattering pattern of amorphous poly(ethylene terephthalate), (PET), was measured during isothermal crystallization using synchrotron radiation. The samples were heated to temperatures between 117 and 145°C in an oven placed in the path of the X-ray beam. The scattering curves were measured within 10 s at intervals of 1 s so as to follow the kinetics of the process continuously. It appears that the distance between the centres of mass of the crystallites decreases with increasing crystallization time as in oriented PET. The integrated small angle scattering follows approximately the same time course as the increase in the degree of crystallinity during an isothermal crystallization yielding Avrami exponents between 5 and 7. Guinier plots of the low angle region show that the scattering can be attributed to rod-like particles.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Time resolved x-ray solution scattering measurements were made during thermal denaturation of DNA from various sources in the temperature range of 20-90°C. Preliminary results on the influence of fragement length, ionic strength, and origin of the DNA on the time course of the scattering are described. Interpretation is based on model calculations of the scattering patterns. The resluts indicate that, for long DNA fragments at very low ionic strength, the melting process is a continuous phenomenon over the whole temperature range. It is accompanied by a progressive decrease of the radius of gyration of the cross section and of the mass per unit length. For short fragments of 146 base pair nucleosomal core DNA, stiffening of the DNA appears to precede a sharp melting transition.
    Additional Material: 7 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 99 (1987), S. 1229-1229 
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 26 (1987), S. 801-802 
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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