Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • 1995-1999  (2)
  • 1980-1984
  • 1965-1969
  • 1950-1954
  • 1999  (2)
  • Key words Knee  (1)
  • monomolecular reaction
Materialart
Erscheinungszeitraum
  • 1995-1999  (2)
  • 1980-1984
  • 1965-1969
  • 1950-1954
Jahr
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Catalysis letters 57 (1999), S. 209-215 
    ISSN: 1572-879X
    Schlagwort(e): 1-butene ; skeletal isomerization ; mesoporous material ; acid site concentration ; monomolecular reaction
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract On the skeletal isomerization of 1-butene, mesoporous materials with mesopores too large to expect any shape selectivity have been used in order to investigate the effects of the concentration of acid sites on the conversion of 1-butene and the selectivity for isobutene. The concentrations of acid sites can be varied through the control of the Si/Al ratio. The conversion of 1-butene increases with increasing the aluminium content of mesoporous materials, while the selectivity for isobutene decreases. The results of ammonia TPD, IR measurement of 1-butene adsorption, and TG analysis of used catalysts indicate that distant location of activated 1-butene molecules induces the monomolecular reaction over the mesoporous materials with low aluminium content, resulting in high selectivity for skeletal isomerization. On the mesoporous material with high aluminium content, however, the high concentration of activated 1-butene molecules accelerates the multimolecular oligomerization and, thus, reduces the selectivity.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    ISSN: 1432-2161
    Schlagwort(e): Key words Knee ; anatomy ; Knee ; MR ; Knee ; ligaments ; menisci ; and cartilage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract  Purpose To demonstrate variations in the meniscofemoral ligaments (ligaments of Wrisberg and Humphrey) at anatomical study and magnetic resonance (MR) imaging. Design Twenty-eight cadaveric knees were partially dissected for the examination of the meniscofemoral ligaments. One hundred knee MR examinations were reviewed by two experienced musculoskeletal radiologists. Proximal variations in the meniscofemoral ligaments at MR imaging were classified into three types according to the attachment site: type I, medial femoral condyle; type II, proximal half of the posterior cruciate ligament (PCL); type III, distal half of the PCL. Distal variations were classified into vertical or oblique types according to the orientation of the intermediate signal at the interface of the ligament and lateral meniscus. Results At anatomical study, six cases showed variations in the proximal insertion site of the meniscofemoral ligaments. At MR imaging 93 cases had one or more meniscofemoral ligaments, giving a total of 107 ligaments: 90 ligaments of Wrisberg and 17 ligaments of Humphrey. Forty-one ligaments of Wrisberg were type I, 28 type II, 19 type III, and with two indeterminate type, while 6 ligaments of Humphrey were type I and the remaining 11 were indeterminate. Seven cases showed no meniscofemoral ligament. Of the 107 meniscofemoral ligaments, the distal insertion orientation was of vertical type in 10 ligaments, oblique type in 70 and unidentified in 27. Conclusion An understanding of the high incidence of meniscofemoral ligament variations may help in the interpretation of knee MR studies.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...