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
  • 1
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Koordinationspolymere von 5,8-Dihydroxy-1,4-naphthochinon mit Fe(III), Co(II) and Ni(II) wurden hergestellt und durch Elementaranalyse, DSC, IR-Spektroskopie und Messung der magnetischen Momente charakterisiert. Aus den DSC-Daten wurden die Reaktionsordnungen und die Aktivierungsenergien des thermischen Abbaus der Polymeren berechnet. Die elektrischen Eigenschaften wie Dielektrizitätskonstante und Wechselstromleitfähigkeit wurden gemessen. Aus Röntgen-Pulverdiagrammen wurden die Elementarzellenparameter berechnet und die Kristallsymmetrie bestimmt.
    Notes: Coordination polymers of Fe(III), Co(II) and Ni(II) with 5,8-dihydroxy-1,4-naphthoquinone have been synthesized and characterized by elemental analysis, IR and magnetic moment studies. From DSC data, the order of the decomposition reaction and the activation energy for the decomposition of the different polymers have been evaluated. Electrical properties like the dielectric constant and the dc conductivity of the polymers have been measured. From x-ray powder diffractograms cell parameters were calculated, the pattern indexed, and the symmetry determined.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 42 (1991), S. 935-945 
    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: Oxoalkyl acrylates of long-chain 7-oxo alcohols were synthesized as intermediate monomers for the preparation of poly[n-alkyl (oxy) -n-hexyl acrylates] for the first time. These polymers have wide applications as fluidity improvers (pour point depressants) for petroleum crude oils. Characterization of all the intermediate monomers was done by IR, 1H-NMR, and MS, and that of polymers by IR, 1H-NMR, and GPC. These polymers were systematically investigated for their efficacy as pour point depressants on three types of high waxy Bombay High (Indian) crudes. In addition to establishing the pour points, relevant rheological parameters of the untreated and the additive-treated crude oils were determined in the laboratory with a rotational viscometer. Results of the crude oils that were pre- and posttreated with these new polymers have shown enhanced activity of flow properties as compared to the crudes that were treated with poly(n-alkyl acrylate) flow improver.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 42 (1991), S. 379-383 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Der Mechanismus der Ladungsspeicherung in Poly(acrylamid)-Filmen wurde mit der Methode der thermisch stimulierten Depolarisationsströme (TSDC) untersucht. Die TSDC wurden in Abhängigkeit von der Feldstärke, der Temperatur und der Dauer der Polarisation bei verschiedenen Aufheizgeschwindigkeiten gemessen. Bei niedrigen Polarisationstemperaturen wurde in den TSDC-Spektren nur ein Peak gefunden, bei höheren Polarisationstemperaturen traten zwei Peaks auf. Der erste Peak wurde der Dipolorientierung, der zweite der Raumladungspolarisation zugeordnet.
    Notes: The charge storage mechanism in poly(acrylamide) films was studied by means of the technique of thermally stimulated depolarization currents (TSDC). The TSDC were measured as a function of field strength, temperature and time of polarization in dependence on the heating rate. One peak was observed on the TSDC spectra at low polarizing temperatures, while two peaks occurred for higher polarizing temperatures. The first peak was attributed to dipole orientation and the second one to space charge polarization.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 42 (1991), S. 465-469 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die stationäre elektrische Leitung in aus der Lösung erhaltenen Poly(acrylamid)-Filmen wurde im Temperaturbereich von 303 bis 450 K bei unterschiedlichen Feldstärken untersucht. Es wurde festgestellt, daß die Richardson-Schottky- und Poole-Frenkel-Mechanismen gleichzeitig auftreten. In mit Eosin bzw. Rhodamin B dotierten Filmen wurde die elektrische Leitung der Bildung von Charge-Transfer-Komplexen zugeschrieben.
    Notes: The steady state electrical conduction in solution grown poly(acrylamide) films was investigated in the temperature range 303 to 450 K at different field strengths. It was found that the Richardson-Schottky and Poole-Frenkel mechanisms operate simultaneously. In films doped with cosin and rhodamine B, respectively, the electrical conduction was attributed to the formation of charge transfer complexes.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Films aus Mischungen von Poly(vinylalkohol) und Poly(vinylpyrrolidon) wurden aus Lösungen der Homopolymere hergestellt. Die stationäre elektrische Leitung wurde im Temperaturbereich 309 K bis 450 K bei Feldstärken von 0,75 bis 46,5 · 106 V/m unter Verwendung unterschiedlichen Elektrodenmaterials untersucht. Der Ladungstransport wird mit der Injektion von Ladungsträgern aus dem Elektrodenmaterial in das Dielektrikum nach einem Richardson Schottky-Mechanismus und nachfolgendem Einfangen und Freisetzung nach dem Poole-Frenkel-Mechanismus erklärt.
    Notes: Polyblend films of poly(vinyl alcohol) and poly(vinyl pyrrolidone) were prepared from solutions of the homopolymers. The steady-state electrical conduction was studied in the temperature range from 309 K to 450 K at the field strength of 0.75 to 46.5 · 106 V/m using different electrode materials. The charge transport is attributed to the injection of charge carriers from the electrode materials into the dielectric according to the Richardson-Schottky mechanism and their subsequent trapping and release according to the Poole-Frenkel mechanism.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 43 (1992), S. 68-71 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Poly(vinylalkohol)-Filme wurden bei unterschiedlichen elektrischen Feldstärken und Temperaturen polarisiert. Die Peaktemperatur der TSDC-Spektren verschob sich mit steigender Polungsfeldstärke und Polungstemperatur zu höheren Werten. Die Aktivierungsenergien und die Relaxationsparameter des Prozesses wurden ermittelt. Auf Grund der Ergebnisse wurde der Ursprung der TSDC der Raumladungspolarisation mit einem geringen von der Dipolorientierung herrührenden Beitrag zugeordnet.
    Notes: Poly(vinyl alcohol) films were polarized at different electrical field strengths and temperatures. The peak temperature of the TSDC spectra shifted to higher values with increasing polarizing field strength and polarizing temperature. The activation energies and relaxation parameters of the process were evaluated. Based on the results, the origin of TSDC was attributed to space charge polarization with some contribution of dipole orientation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 192 (1991), S. 51-55 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: N,N-Dimethylacrylamid (DMA) und Isopropylmethacrylat (IPM) wurden in Dimethylformamid mit Azoisobutyronitril als Initiator copolymerisiert. Die Copolymerzusammensetzung wurde 1H-NMR-spektroskopisch ermittelt. Die Copolymerisationsparameter (rDMA = 0,58, rIPM = 2,76) wurden nach Kelen-Tüdős berechnet.
    Notes: Copolymers of N,N-dimethyl acrylamide (DMA) and isopropylmethacrylate (IPM) were prepared in dimethyl formamide using azoisobutyronitrile as initiator. The composition of copolymers was determined by 1H-NMR analysis. Reactivity ratios (rDMA = 0.58, rIPM = 2.76) were calculated from these values by using the Kelen-Tüdős differential linear equation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Molecular dynamics simulations on the sequence d(CGCGAATTCGCG)2 have been carried out using both united atom and all-atom representations, and starting the simulations both from a regular repeating B-DNA structure and from the x-ray single crystal B-DNA structure. An all-atom B-DNA simulation on the sequence d(GCGCGCGCGC)2 has also been carried out, in order to compare it with a previous united atom simulation. The helix repeats, H-bonding, sugar pucker profiles, and average torsional angles are all in the range observed in crystallographic and nmr studies for B-DNA helices. In some of the sequences, there is a significant bend in the DNA helices. The individual helix repeats, with focus on 3′CpG5′ and 3′GpC5′ units, show the opposite helix repeat to that suggested by Calladine's rules.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 192 (1991), S. 1025-1032 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Polyimides were prepared from the reaction of two aromatic dianhydrides with two diamines containing carbonyl and ether connecting groups between the aromatic rings. The diamines were prepared from the reaction of 4-aminophenol or (3-aminophenol) with an activated aromatic difluoro compound (4,4′-difluorobenzophenone) in the presence of potassium carbonate. Some of these polyimides were shown to be semicrystalline as evidenced by wide-angle X-ray diffraction. Glass transition temperatures were observed between 203 and 242°C. All polyimides were found to be thermally stable up to 400-450°C with a char yield of about 50-60% at 900°C. The effect of the structure on the properties of polyimides, such as crystallinity, glass transition temperature and thermal behaviour, is discussed.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 194 (1993), S. 1095-1104 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Poly(aspartic acids) of different chain lengths (11, 14, 18, 24, 30, 52, 58, ≈ 115) were prepared, for the use in aminoglycoside-induced nephrotoxicity inhibition studies, some in their pure L- or D-configuration and in pure α-linkage form by the polymerization of α-amino acid N-carboxyanhydride (NCA) derivatives with a variety of dialkyl aspartate molecules as primary amine initiators. The primary amine chosen served as an internal reference in the 1H NMR spectrum for the estimation of the degree of polymerization (chain length) in these molecules. Poly(aspartic acids) with varying amounts of D and L asymmetric centres and in pure α-linkage from were also prepared. Poly[(α-co-β)(L-co-D) aspartic acid] was prepared by a simplified thermal polymerization procedure for biological studies and also to study the tacticity effects in its 13C NMR spectrum. A qualitative correlation was demonstrated between the retention times from gel-permeation chromatographic analysis and the 1H NMR method used to estimate the polymer chain length.
    Additional Material: 3 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...