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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 8 (1966), S. 405-431 
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 11 (1965), S. 1124-1132 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Flow regimes occurring during evaporation of Freon-12 (dichlorodifluoromethane) and Freon-22 (monochlorodifluoromethane) inside five tubes were investigated. Two flow models are proposed, one each for vertical and horizontal tube orientation. The limits of each flow regime were determined and heat transfer correlations obtained. The most significant flow regimes were found to be nucleate boiling, annular flow, and mist flow. A correlation for the transition between annular flow and mist flow was obtained.
    Additional Material: 15 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 739-755 
    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 steady-state viscosity of a number of cis-polybutadienes was determined as a function of shear rate and temperature by use of a capillary rheometer. Polymers investigated differed in molecular weight distribution and long chain branching. None of the polymers exhibited Newtonian behavior, even at the lowest shear rates attainable. Nevertheless, for polymers of similar molecular weight distribution and minimum branching, all the capillary viscometer data could be reduced to a single curve by a reduced variable treatment. The molecular weight shift function was found to be the same as for polymers exhibiting a Newtonian flow range, i.e., a 3.4th power law in weight-average molecular weight. Broadening the molecular weight distribution or increasing the degree of long-chain branching led to increasingly pronounced non-Newtonian behavior. Tensile creep experiments showed nonlinear viscoelastic behavior for all polymers studied, even at small strains. This behavior was most pronounced in the more highly branched polymers. At very low stresses some of these polymers exhibited extremely high viscosities, the strain being almost completely recoverable. Under larger stresses the viscosity of these rubbers dropped several decades and in the capillary extrusion experiments these polymers flowed readily. This is the same behavior observed previously in high molecular weight branched (multichain) narrow distribution polybutadienes. It is tentatively explained by a constraint of the branch points on the slippage of chain entanglements. The fact that all cis-polybutadienes exhibit this behavior, while linear polybutadienes made by organolithium initiation do not, suggests that all cis-polybutadienes may be branched to some extent.
    Additional Material: 11 Ill.
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  • 4
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The optical rotatory dispersion of copolymers of O-carbobenzoxy-L-tyrosine and benzyl L (or D)-glutamate as well as benzyl L-aspartate, dissolved in nonpolar solvent, has been studied. Moffitt's equation permits the determination of b0 coefficients whose variation, with varying composition in amino acid residues, suggests that the molecules of poly-O-carbobenzoxy-L-tyrosine have a helical structure similar to that of poly-(benzyl L-glutamate). Results obtained from infrared spectroscopy and x-ray diffraction show that the copolymers possess a helical conformation in the solid state, even when they are very rich in carbobenzoxy-L-tyrosine residues. The value of the b0, coefficient for poly-O-carbobenzoxy-L-tyrosine may be explained by a regular stacking of the chromophore groups around the helical backbone. The ordering of the molecules of this polymer in a purely helical structure seems favored by the insertion of a small number of foreign residues in the polypeptide chain.
    Additional Material: 4 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part B: Polymer Letters 3 (1965), S. 887-889 
    ISSN: 0449-2986
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Tab.
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  • 6
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Durch elektrophile Substitutionen wird die Struktur des Tetrabrom-isosafrols (2b) bewiesen. Die Synthese von 3-Amino-4.5-methylendioxy-benzoesäuremethylester (4j) über 3-Nitro-piperonylsäuremethylester (4h) wird beschrieben.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 1 (1969), S. 191-202 
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The accuracy of several methods for deuterium content determination in organic molecules are tabulated. The sample-substitution (using one or two NMR sample tubes) and internal standard (inter- or intra-molecular) processes are discussed and compared. These methods are applied to some examples and the NMR results are confirmed by mass spectrometry.
    Notes: Les précisions de différentes méthodes de détermination du taux de deutériation de molécules organiques par RMN sont évaluées. On compare successivement les méthodes de changement de tube-échantillon et les méthodes utilisant un étalon interne. Ces méthodes sont ensuite appliquées au dosage du deutérium dans plusieurs molécules et les résultats sont comparés à des mesures de spectrographie de masse.
    Additional Material: 1 Ill.
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  • 8
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Magnetic non-equivalence of methylenic protons in A—CH2—CH3 groups were studied for several types of compounds. Results are compared with respect (1) to the nature of heteroatom A:A = O and A = S and (2) to the structure of the local dissymmetry element: asymmetric carbon, ketal group and allenic system. Influence of substitution is discussed in relation to conformational problems. Furthermore a variation of the methylene geminal coupling constant with substituents of carbon α to OEt is observed.
    Notes: La non-équivalence magnétique des protons méthyléniques de groupements A—CH2—CH3 est étudiée dans plusieurs séries de composés. Les effets sont comparés d'une part dans les séries A = O et A = S, d'autre part dans les composés présentant un carbone asymétrique, un carbone de type cétal ou une dissymétrie allénique. L'influence de la substitution sur le carbone en α de AEt est discutée en relation avec les conformations. Une variation de la constante de couplage entre les protons méthyléniques géminés en function de la nature des substituants lointains est mise en évidence.
    Additional Material: 6 Tab.
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  • 9
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Various complexes of boron trifluoride and typical organo-phosphours compounds have been investigated using proton and fluorine resonance (at variable temperature) and boron and phosphorus resonance. In BF3, boron resonance is insensitive to the complex strength, but fluorine resonance suggests the possibility of various types of complexes on the phosphorus group or, additionally on the heteroatoms (e.g. oxygen, nitrogen) of the molecule. These complexes are probably σ type. Proton chemical shifts in the organo-phosphorus compounds follow the same trends as in similar complexes of amines, esters etc.; these perturbations may be mainly due to magnetic anisotropy effects; proton-phosphorus couplings conversely follow changes in phosphorus electronegativity.
    Notes: On a étudié, en résonance du proton et du fluor (à température variable) ainsi qu'en résonance du bore et du phosphore, un certain nombre de complexes entre BF3 et des composés organo-phosphorés typiques. En ce qui concerne BF3, la résonance de bore reste insensible à la force du complexe; par contre, la résonance du fluor suggéère l'existence de plusieurs types de complexes, soit sur le groupe phosphoré, soit sur les hétéroatomes (par example N, O) de la molécule. Ces complexes sont vraisemblablement de type σ pur. Le déplacement chimique des protons dans la molécule organo-phosphorée subit sensiblement les mêmes perturbations que dans les autres molécules complexables (amines, esters, etc.); ces perturbations peuvent provenir avant tout d'effets d'anisotropie magnétiques; par contre, les couplages proton-phophore suivent la modification de l'électronégativité de ce dernier.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science Part A: General Papers 3 (1965), S. 1969-1984 
    ISSN: 0449-2951
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to study some aspects of radical polymerization initiated by a polymer, hexanediol sebacates in different degrees of polymerization were prepared. The endgroup was the tert-butyl perester which was used to polymerize the styrene. With such compounds, it is easy after the polymerization to take off the polyester backbone by hydrolysis. One can then study the mixture of polystyrene sequences and homopolystyrene made at the same time. It appears that if the speed of thermal decomposition of the tert-butyl perester group on the polyester is of the same order as that of the tert-butyl perbenzoate, the efficiency factor, i.e., the fraction of free radicals which effectively initiates the polymerization, is much smaller with a polymeric initiator. Moreover, the average degree of polymerization is much smaller in this case (even in the presence of a nonperoxidized polyester). It is believed that these two results can be explained by assuming each polyester backbone to act as a cage for the free radicals produced by its own perester group which aids their recombination and intramolecular transfer.
    Additional Material: 12 Ill.
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