ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
Your search history is empty.
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Chemistry  (33)
  • ribosomal RNA genes  (2)
  • 1975-1979  (35)
  • 1
    Electronic Resource
    Electronic Resource
    Gene action in fish of tetraploid origin. III. Ribosomal DNA amount in cyprinid fish (1976)
    Springer
    Biochemical genetics 14 (1976), S. 19-26 
    Details
    ISSN: 1573-4927
    Keywords: evolution ; polyploidy ; ribosomal RNA genes ; cyprinid fish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Phylogenetically diploid and tetraploid cyprinid fish species have cells of very similar volumes and protein contents. This finding has prompted us to postulate a regulatory system established during the evolution of the tetraploids leading to a diploid state of genic expression. It was proposed that this might be accounted for by a selective loss of ribosomal genes. RNA-DNA hybridization experiments, however, reveal a clear-cut 1:2 relationship of ribosomal DNA amounts between the diploid and the tetraploid species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484870
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Gene action in fish of tetraploid origin. IV. Ribosomal DNA amount in clupeoid and salmonoid fish (1976)
    Springer
    Biochemical genetics 14 (1976), S. 293-297 
    Details
    ISSN: 1573-4927
    Keywords: evolution ; polyploidy ; ribosomal RNA genes ; Isospondyli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Phylogenetically tetraploid species of the fish order Isospondyli generally have twice the mean ribosomal gene content as closely related species on the phylogenetically diploid level. Considerable intraspecific variation of rDNA amount was observed. These findings are discussed in view of the hypothesis that selective loss of ribosomal genes may account for diminishing genic activity in phylogenetically tetraploid organisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00484768
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Ein einfaches Verfahren zur Bestimmung gültiger Bruchzähigkeitswerte von Hartmetallen (1978)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 9 (1978), S. 128-132 
    Details
    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: A Simple Method of Determining Valid Fracture Toughness Data of Cemented CarbidesFrom a comparison of published data it follows that a valid determination of the fracture toughness of cemented carbides depends on the use of samples containing sharp cracks. It is shown that using the technique of controlled fracture experiments sharp cracks of a given length can be introduced easily and reproducibly into bend specimens. A new evaluation method permits the fracture toughness to be calculated without knowing the crack length if the compliance of the pre-cracked specimen is measured. The KIc values determined in this way are characterized by a very small scatter and agree well with data from the literature which were obtained from specimens of similar composition. A comparison of the flaw size calculated from KIc and the bend strength to the failure size detected in fractographic studies shows very good agreement.
    Notes: Ein Vergleich von Literaturergebnissen ergibt, daß die Bruchzähigkeit von Hartmetallen nur dann gültig bestimmt wird, wenn Proben mit scharfen Anrissen benutzt werden. Es wird gezeigt, daß mit Hilfe der Technik des kontrollierten Bruchversuchs scharfe Anrisse vorgegebener Länge in Biegeproben leicht und reproduzierbar erzeugt werden können. Eine neuartige Auswertemethode gestattet es, die Bruchzähigkeit ohne Kenntnis der Rißlänge zu ermitteln, wenn statt dessen die Nachgiebigkeit der Nachgiebigkeit der angerissenen Probe gemessen wird. Die so bestimmten KIc -Werte weisen eine sehr geringe Streuung auf und stimmen mit Literaturwerten, die über ebenfalls scharf angerissene Hartmetalle ähnlicher Zusammensetzung bekannt sind, gut überein. Der Vergleich zwischen der aus KIc und der Bruchspannung berechneten Fehlergröße mit der fraktographisch gefundenen zeigt sehr gute Übereinstimmung.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19780090406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Berechnung des Kriechverhaltens zylindrischer Hohlkörper mit radialem Temperaturgradienten (1979)
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 10 (1979), S. 243-248 
    Details
    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: Theoretical Investigation of the Creep Behaviour of a Tube Subjected to Thermal and Mechanical LoadingA tube specimen, in which a constant temperature distribution of axial symmetry is maintained and which is subjected to a constant axial tensile stress is considered. Calculation of the thermal stress and creep strain distribution requires detailed knowledge of the physical properties of the material. A stress analysis, based on successive approximations, is given, which has been extended into the plastic deformation range. As a result, it can be shown that the initial stress pattern is redistributed by time-dependent creep, yielding in a more homogeneous uniaxial stress distribution. From these results a simple formula is derived which gives the steady state stress distribution as well as a characteristic mean or “effective” value of the temperature within the tube wall.
    Notes: Das Kriechverhalten einer zylindersymmetrischen Hohlprobe, die mit einem radialen Temperaturgradienten belegt ist und axial belastet wird, wird theoretisch untersucht. Ausgehend von der genauen Kenntnis der physikalischen Werkstoffeigenschaften wird die elastische Spannungsverteilung berechnet und die Analyse mittels einer numerischen Approximationsmethode auf den nicht-elastischen Bereich erweitert. Es zeigt sich, daß durch zeitabhängige Fließvorgänge Spannungsumverteilungen stattfinden, die schon im Bereich kleiner Dehnungen zu einem einachsigen, stationären Spannungszustand führen. Aus diesen Ergebnissen wird ein einfacher Ansatz für ein charakteristisches Beanspruchungsprofil abgeleitet, dessen Merkmale die stationäre Spannungsverteilung und eine mittlere Temperatur sind, mit denen das Gesamtkriechverhalten dargestellt werden kann. Der Einfluß lokaler Kriechschädigung auf die Restlebensdauer wird abgeschätzt.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mawe.19790100707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A computer implementation of frequency-temperature superposition for dynamic mechanical transformations (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 19 (1975), S. 791-799 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The usual procedure for shifting dynamic mechanical data, involving the construction of a master plot, was compared with a simpler, computer-implemented double shift procedure, which obviates the need for such a construction. Data reproducibility indicates that the double shift may successfully be shifted to frequencies greater than one decade to either side of the experimental range.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1975.070190316
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Mechanochemical aspects of repetitive impacts and sliding on polymers (1979)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 24 (1979), S. 1503-1514 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Scattered data exist in the literature on the chemical reactions which occur during mechanical contact. It is our contention that these reactions occur as a direct result of the high temperatures generated at the contact interface, due to the dissipation of mechanical energy. A theoretical analysis is used to identify and rank the various sources of heat generation during repetitive impact or sliding. New data, on both filled and unfilled polymers and elastomers, supported by data from the literature, are used to show that the resultant temperature rise causes reactions at the interface; the extents of these reactions depend on the polymer structure and the magnitude of the temperature rise. Several ways of reducing the magnitude of this temperature rise are discussed.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1979.070240611
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Acetoxytropyliumbromid: Synthese, Strukturbeweis, Verhalten in Lösung17. Mitt. über Fulvene und Fulvalene, 16. Mitt. siehe [1]. - Mitt. Nr. 272 der Abteilung für Kristallographie und Strukturlehre, Universität Bern. (1976)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 59 (1976), S. 2344-2354 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acetoxytropyliumbromide: Synthesis, Structural Evidence, Behaviour in Solution.Acetoxytropyliumbromide (9) is formed from tropone and acetylbromide. In solution the tropylium salt equilibrates with the educts, 9 being favored at low temperature in polar aprotic solvents. The structure of the title compound has been proved by X-ray analysis, as well as by investigation of the 1H-NMR. spectra of solutions of 9.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19760590707
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Über Bismuthaltige Silicatapatite. Ungewöhnliche Oxidapatite (1979)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 449 (1979), S. 127-134 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Silicate Apatites Containing Bismuth. Unusual Oxide ApatitesThe compositions Ca3,2Bi6,8(SiO4)6O1,4 □0,6 and Sr2,8Bi7,2 (SiO4)6O1,6□0,4 have been ascertained for the thermally formed oxide apatites. The metastable apatite phase with a homogeneity range from Pb5,2Bi4,8(SiO4)6O0,4 □1,6 to Pb6Bi4(SiO4)6□2 crystallizes from the glassy state below 600°C. The vacancies □ correspond to the unoccupied halide positions. Ca3,2Bi6,8(SiO4)6O0,8 (OH)1,2 (hydrothermal synthesis) and Pb4Bi6(SiO4)6F2 show the usual stoichiometry, however. The peculiar electron configuration of Bi3+ and Pb2+ is considered responsible for the differences from apatites of La3+ and of the alkaline earth ions.
    Notes: Für die thermisch entstandenen Oxidapatite wurde die Zusammensetzung Ca3,2Bi6,8(SiO4)6O1,4 □0,6 bzw. Sr2,8Sr2,8Bi7,2 (SiO4)6O1,6□0,4 ermittelt. Die metastabile Apatitphase mit dem Homogenitätsbereich von Pb5,2Bi4,8(SiO4)6O0,4 □1,6 bis Pb6Bi4(SiO4)6 □2 kristallisiert unterhalb 600°C aus dem Glaszustand. Die Lücken □ entsprechen den unbesetzten Halogenidlagen. Dagegen weisen Ca3,2Bi6,8(SiO4)6O0,8 (OH)1,2 (Hydrothermalsynthese) sowie Pb4Bi6(SiO4)6F2 die übliche Stöchiometrie auf. Die besondere Elektronenkonfiguration von Bi3+ und Pb2+ wird für die Unterschiede gegenüber den Apatiten des La3+ und der Erdalkaliionen verantwortlich gemacht.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19794490113
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Über Bleisilberphosphate mit Apatitstruktur (1979)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 448 (1979), S. 71-78 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On Lead Silver Phosphates with the Apatite StructureThe hitherto unknown leas silver phosphate (Pb8Ag2PO4)6 has been prepared. It has an apatite structure with unoccupied halide positions like the analogous lead alkali compounds and forms solid solutions with Pb10(PO4)6O, Pb10(PO4)6(OH)2, and Pb10(PO4)6Cl2. At 800°C, Pb8Ag2(PO4)6 decomposes to solid Pb3(PO4)2 and PbAgPO4. (Pb, Ag) apatites have been precipitated from aqueous solutions. On the side being richer in Ag they can approximately be formulated as solid solutions between Pb8Ag2(PO4)6 and Pb10(PO4)6(OH)2. However, the i.r. spectrum reveals clear differences compared with thermal and hydrothermal preparations. The distribution of cations shows nonideal behaviour with reduced tendency for fixation of Ag+, if the content of Ag in the precipitate is high. The compound PbAgPO4 decomposes below 520°C to Pb8Ag2(PO4)6 and Ag3PO4. The arsenate apatite Pb8Ag2(AsO4)6 decomposes below 530°C to Pb3(AsO4)2 and Ag3AsO4.
    Notes: Dargestellt wurde das bisher unbekannte Bleisilberphosphat Pb8Ag2(PO4)6. Es besitzt wie die analogen Bleialkaliverbindungen eine Apatitstruktur mit unbesetzten Halogenidlagen und bildet Mischkristalle mit Pb10(PO4)6(OH)2 sowie Pb10(PO4)6Cl2. Bei 800°C zersetzt sich Pb8Ag2(PO4)6 in festes Pb3(PO4)2 und PbAgPO4. Aus wäßriger Lösung gefällte (Pb, Ag)-Apatite können auf der Ag-reicheren Seite näherungsweise als Mischkristalle zwischen Pb8Ag2(PO4)6 und Pb10(PO4)6(OH)2 beschrieben werden. Allerdings weist das IR-Spektrum klare Unterschiede gegenüber thermischen und hydrothermalen Präparaten auf. Die Kationenverteilung zeigt nicht ideales Verhalten mit verminderter Tendenz zum Ag+-Einbau, wenn der Ag-Gehalt des Niederschlags hoch ist. Die Verbindung PbAgPO4 zerfällt unterhalb 520°C in Pb8Ag2(PO4)6 und Ag3PO4. Der ebenfalls dargestellte Arsenatapatit Pb8Ag2(AsO4)6 zersetzt sich unterhalb 530°C in Pb3(AsO4)2 und Ag3AsO4.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19794480107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Neue Phosphate mit Eulytinstruktur, insbesondere Europium(II)-Verbindungen [1] (1975)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 417 (1975), S. 81-88 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: New Phosphates with Eulytine Structure, especially Europium(II) Compounds.A number of Eu(II) phosphates Eu3IILn(PO4)3 have been prepared, where Ln—La, lanthanides, Y. All investigated compounds have colours from yellow to ockre and crystallize with the cubic structure of eulytine (Bi4(SiO4)3). Eu3II(PO4)3 makes an exception, showing a lattice deformation to low symmetry. It converts to a cubic eulytine phase by partial oxydation. The peculiar run of the lattice constants of the Eu(II) compounds in the lanthanide series is compared with the behaviour of the analogous Sr, Pb, and Ba compounds. Moreover, the eulytine compounds Pb3MIII(PO4)3 with MIII—V, Cr, Fe have been synthesized. Experiments with TiIII yield solid solutions between Pb3TiIII(PO4)3 and Pb7TiIV(PO4)6.
    Notes: Eine Anzahl Eu(II)-Phosphate Eu3IILn(PO4)3 wurde dargestellt, wobei Ln—La, Lanthaniden, Y. Alle untersuchten Verbindungen sind gelb bis ocker gefärbt und kristallisieren in der kubischen Struktur des Eulytins (Bi4(SiO4)3). Eine Ausnahme bildet Eu3IIEuIII. (PO4)3, das eine niedersymmetrische Gitterverzerrung zeigt. Durch partielle Oxydation erhält man daraus eine kubische Eulytinphase. Der auffallende Verlauf der Gitterkonstanten der Eu(II)-Verbindungen in der Lanthanidenreihe wird mit dem Verhalten der analogen Sr-, Pb- und Ba-Verbindungen verglichen. Zusätzlich wurden die Eulytinverbindungen Pb3Miii(PO4)3 mit MIII—V, Cr, Fe synthetisiert. Versuche mit TiIII führen zu Midchkristallen zwischen Pb3TiIII(PO4)3 und Pb7TiVI(PO4)6.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19754170202
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...