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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 141 (1955), S. 146-159 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Zusammenfassung Die Oberflächenfeinstruktur definierter Grenzflächen von Quarz wurde studiert. Es wurde versucht, die wahrscheinlichsten Adsorptionsörter für Atome und Molekeln verschiedenen Bindungszustandes abzuleiten und auch ihre Zahl je Gittermasche in Abhängigkeit von ihrem Raumbedarf bzw. den Bedeckungsgrad der Oberflächen im „monomolekularen Film“ zu ermitteln. Es ergaben sich interessante Unterschiede im Zusammenhang mit der Anisotropie der Substanz. Die Ergebnisse mahnen zur Vorsicht hinsichtlich einer allzu schematischen Mittelung für mikrokristalline Pulver, deren Oberflächencharakter unbekannt ist. Es scheint damit sogar zweifelhaft, ob eine Oberflächenermittlung bei Pulvern auf Grund definierter Adsorbatmengen allein aus der Kenntnis des Raumbedarfs der adsorbierten Partikel zu richtigen Werten führt.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 210 (1971), S. 76-96 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Unsere Untersuchungen galten der Klärung der kristallographischen Grundlagen des Arborisationsphänomens des Cervicalschleimes. Nach einer kurzen Darstellung der Methodik und der wichtigsten Bestandteile des Cervixschleimes wurden zunächst kristallographische Untersuchungen von Nativschleimen bei 90 Frauen zu verschiedenen Zeiten des Cyclus' unter konstanten, reproduzierbaren Versuchsbedingungen durchgeführt. Da es sich bei dem auskristallisierten Material des Cervixschleimes praktisch ausschließlich um Kochsalz handelt, galten unsere weiteren Untersuchungen der Wachstumsmorphologie des Steinsalzes. Natriumchlorid kristallisiert unter idealen Versuchsbedingungen in reiner, wäßriger Lösung in Form von Würfeln. Auf Grund der hohen Symmetrie sowie der geringen und unspezifischen Komplexbildungstendenz ist diese Kristallart wachstumsmorphologisch wenig modulationsfähig und wenig empfindlich. Das Farnphänomen ist aus diesem Grunde auch nicht spezifisch. Wir konnten zeigen, daß eine Reihe meist hochmolekularer, oberflächenaktiver Stoffe neben einigen Sexualhormonen ein dendritenförmiges Wachstum des Natriumchlorids auslösen, das dem des Cervixschleimes weitgehend entspricht. Von allen untersuchten Substanzen vermochte nur Chondroitinsulfat A das Dendritenwachstum in einer Weise zu beeinflussen, daß es praktisch vollständig dem Bild der präovulatorischen Phase mit seinem typisch wellenförmigen Verlauf entsprach. Man darf daher annehmen, daß das Farnphänomen im wesentlichen durch die im Cervixschleim enthaltenen Schleimsubstanzen hervorgerufen wird. Der optimale Bereich für die Dendritenbildung lag bei fast allen untersuchten Substanzen bei einer Relation von 0,2 mg zu 0,2 ml einer 0,93%igen NaCl-Lösung. Dieses Verhältnis findet sich auch im Cervixschleim um den Ovulationstermin. Bei einem Anstieg der Lösungsgenossen über 0,5 mg bei konstanter NaCl-Konzentration wurde durch eine zunehmende Schutzkolloidbildung jedes Dendritenwachstum unterbunden; diese Relation findet man im Cervixschleim in der frühen Follikelphase und in der Corpus luteum-Phase.
    Notes: Summary The study reported in this paper concerns itself with the investigation of the crystallographic basis of the so-called “cervical mucus fern pattern”. Exact methods are the prerequisite to obtain reproducible results. The cervical mucus of 90 women was studied during different phases of the menstrual cycle under constant reproducible experimental conditions. Since the crystallized material of cervical mucus consists almost entirely of sodium chloride, additional experiments were carried out to study “growth-morphology” of this salt. Sodium chloride in pure water solution crystallizes in the shape of cubes under ideal experimental conditions. Due to its high degree of symmetry as well as the insignificant and unspecific tendency to form complexes, this type of crystal is quite insensitive and cannot be modulated in respect to its growth-morphology. The fern phenomenon, therefore, cannot be considered to be specific. Some sexual hormones, several high-molecular, surface-active substances caused dendrite-like growth of this salt, similar to that of cervical mucus. Of all substances tested, only chondroitinsulphate A was capable of influencing the growth of dendrites in a manner almost identical to that of the pre-ovulatory phase. This observation leads us to believe that the fern pattern is essentially induced by mucoids contained in the cervical mucus. The optimal range for the formation of dendrites was found to be at a relation of 0.2 mg to 0.2 ml of a 0.93% NaCl. This relation exists also in the cervical mucus at and around the time of ovulation. When the concentration of substances tested increased above 0.5 mg at constant NaCl-level, all growth of dendrites ceased due to an increasing formation of protective colloids. This relation is present also in cervical mucus during the early follicle phase as well as the corpus luteum phase.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2021
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Electrical conductivities of Ni2SiO4, Fe2SiO4, and MgSiO3 were measured on synthetic powders in the temperature range 340° to 1,100° C and at pressures up to 20 kbars. For ternary compounds such as olivines and pyroxenes the control of two further variables, like the chemical activities of two components are needed, besides temperature and pressure. The activities of the corresponding binary oxides were controlled by equilibrating the samples with their neighbour-phases. Control of the oxygen partial pressure was achieved by buffer techniques. From the slopes of the lg σ vs. 1/T lines the activation energies were calculated for 10 kbar: 0.56 eV and 2.7 eV for Ni2SiO4 in equilibrium with SiO2 and Ni/NiO-buffer for the temperature range 500°–800°C and 800°–1,000°C resp. 0.52 eV for Fe2SiO4 in equilibrium with SiO2 and metallic iron, and 0.38 eV in equilibrium with SiO2 and magnetite; 1.11 eV for MgSiO3 in equilibrium with SiO2, and 1.25 eV in equilibrium with Mg2SiO4.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 60 (1973), S. 112-112 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 142 (1955), S. 192-192 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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