ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

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  (38)
  • Cyprinidae  (1)
  • 1975-1979  (34)
  • 1950-1954  (5)
  • 1
    ISSN: 1573-4927
    Keywords: evolution ; polyploidy ; RNA content ; protein content ; enzyme activities ; Cyprinidae ; Isospondyli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The ratio of cellular RNA and protein content is about 1:1 between phylogenetically diploid and tetraploid species of the teleost family Cyprinidae, but is roughly in proportion to ploidy in species of the teleost order Isospondyli. Enzyme activities do not unequivocally comply with this scheme. These findings are discussed in view of the hypothesis that a regulatory mechanism which reduces genic activity has evolved in the tetraploid cyprinids but not in the tetraploid species of the order Isospondyli.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Biopolymers 17 (1978), S. 837-842 
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A theoretical basis for thin-film dialysis involving binding between a ligand and nondialyzing species is presented. A general differential equation that applies to the case of equivalent, noninteracting sites is derived relating [A]F, [A]T, [P]T, and K. Numerical solutions to this equation are used to develop a series of escape curves corresponding to specific values of the parameters [P]T, [A]i, K, and k0. A general method for determining an equilibrium binding constant from thin-film dialysis data is given. A comparison of thin-film dialysis results predicted by this theory with literature data shows essential agreement.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Structure of the Sesquiterpenes of Petasites hybridus (L.) G. M. et SCH.: Petasol and Isopetasol DerivativesThe structure of 11 compounds of the sesquiterpene fraction of petasites hybridus has been determined by combination of spectroscopic methods, especially by analysis of the 360-MHz-1H-NMR. spectra. Most natural products are esters of two isomeric sesquiterpene alcohols, characterized by an eremophilan skeleton, namely of petasol as well as of isopetasol. The structure of one key product has been confirmed by X-ray analysis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Isomerization of the Bis(triphenylphosphine)platin(0) Complexes of Bicyclo[4.2.1]non-1-ene and Bicyclo[4.2.1]non-1(8)-eneIsomrisation of the Bredt-Olefins 3 and 7 as the bis (triphenylphosphine)-Pt(0) complexes 1 and 8, respectively, has been observed. The bridgehead-olefin 3 as well as the bicyclic olefins 4, 5 and 6 have also been isomerized with catalytical amounts of (ethylene)bis(triphenylphosphine)platinum(0) (2).
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Attempted Synthesis of Nonafulvenes and of NonaheptafulvaleneThe reaction of cyclononatetraenide with α-bromobenzyl acetate (6) as well as with 1,1-dihalodimethylether gives at -50°, instead of the expected cyclononatetraenes, bicyclo[6.1.0]nona-2,4,6-triene derivatives 10d and 16 (Scheme 3 and 5, respectively). It seems that in some cases the well known thermally disrotative valence isomerization of cyclononatetraenes 7 to 3a, 7a-dihydroindenes 8 is much slower than the formation of bicyclo[6.1.0]nona-2,4,6-trienes of the type 10 and 16. This type of reaction hurts the Woodward-Hoffmann rules.Possible precursors of the attractive nonaheptafulvalene are prepared by reaction of acetoxy-tropylium fluoborate (19a) as well as of bromo-tropylium bromide (19b) with lithium-cyclononatetraenide (Scheme 8). So far, the attempted gas-phase pyrolysis of the precursors 21a and 21b failed to give nonaheptafulvalene (5).
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 2257-2260 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The kinetics of polycondensation of sebacoyl chloride with α,ω-alkane dioles HO - (CH2)n - OH (5≤n≤10) in dioxane can be described by a second order law related to the functional groups. The rate constants at a given temperature have all the same value within the accuracy of the measurements. The mean values of the rate constants are k=0,63·10-3mol-1ls-1 (T=299,9 K),k=1,19·10-3mol-1ls-1 (T=312,9 K), and k=2,98·10-3mol-1l s-1 (T=331,8 K). Thus, these polycondensation reactions are independent of the chain length of the α,ω-dioles. The mean activation energy is EA=41 kJ mol-1 and the pre-exponential factor is A=8,5·10×3 mol-1ls-1.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 2987-2989 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 180 (1979), S. 2991-2993 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 9 (1978), S. 128-132 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Materialwissenschaft und Werkstofftechnik 10 (1979), S. 243-248 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...