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  • 1
    Electronic Resource
    Electronic Resource
    Orbital electronegativity and electron affinity of rare earth atoms using Xα-theory (1980)
    Springer
    Theoretical chemistry accounts 58 (1980), S. 69-71 
    Details
    ISSN: 1432-2234
    Keywords: Rare earth atoms, Electronegativity, Ionization potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Slater's transition state concept and the relativistic numerical Hartree-Fock-Slater theory has been used to calculate the electronegativity and first ionization potential for the rare earth atoms. Based on these results the electron affinity has also been estimated. The theory predicts almost constant values of the electronegativity as ∼2 eV, first ionization potential as ∼8 eV and the electron affinity of ∼ -(4–5) eV respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00635724
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative studies of static dipole polarizabilities of ionic crystals on the basis of different self-consistent potentials (1981)
    Springer
    Theoretical chemistry accounts 59 (1981), S. 299-307 
    Details
    ISSN: 1432-2234
    Keywords: Dipole polarizabilities ; Ionic crystals ; Density functional theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The static dipole polarizabilities, α D , have been studied for the ions O2−, F−, Na+, Mg2+, Cl−, K+ and Ca2+ in the crystals NaF, KF, NaCl, KC1, MgO and CaO. The starting zero-order wave functions have been generated using various exchange- and exchange-correlation potentials in order to study the effect of these potentials on α D . The direct contribution to the dipole polarizability, α o D , has been determined by the uncoupled Hartree-Fock method. Self-consistency effects have been included by the geometric approximation. The crystal potential is incorporated using the Watson sphere model. Good agreement between theoretical and experimental results are found for those self-consistent potentials which exclude self-interaction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00551357
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  • 3
    Electronic Resource
    Electronic Resource
    Capsules with prolonged action. II. Capsule filling by a gelation process (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 230-234 
    Details
    ISSN: 1573-904X
    Keywords: soft gelatin capsules ; sustained release ; gel formation ; ethylcellulose ; polyethylene glycol ; citric acid triethylester ; diffusion model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A new formulation for manufacturing sustained-release soft gelatin capsules was investigated. It consists of a gel solid formed by ethylcellulose and sesame oil and 20 to 35% polyethylene glycol 400 for the enhancement of drug release. Citric acid triethylester (Citroflex-2) makes it possible to combine sesame oil with polyethylene glycol. By recording the rheological behavior at various temperatures, the thixotropic properties of the mixture that leads to the gel-forming process were ascertained. The ideal temperature for filling into soft gelatin capsules can also be determined by this method. The release profile of codeine dissolved or suspended in the mixture shows the typical matrix-type release. In contrast, a high amount of theophylline suspended in the carrier system yields an erodible matrix with an almost-constant release rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016342830986
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  • 4
    Electronic Resource
    Electronic Resource
    Capsules with prolonged action. III. Release of active ingredients from cast films (1986)
    Springer
    Pharmaceutical research 3 (1986), S. 235-239 
    Details
    ISSN: 1573-904X
    Keywords: soft gelatin capsules ; sustained release ; gel formation ; ethylcellulose ; polyethylene glycol ; citric acid triethyl ester ; diffusion model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In the preceding paper we described a gelation process and the development of sustained-release soft gelatin capsules containing codeine or theophylline. Applying this process to indomethacin and nifedipine as active ingredients led to insufficient release rates of the products. To investigate this phenomenon two simple membrane models were used, i.e., a cast drug-free membrane composed of different ratios of polyethylene glycol 400 in a matrix of 5% ethylcellulose, 10% sesame oil, and 57 to 69% citric acid triethyl ester and a cast drug-containing membrane with the same excipients. Codeine and indomethacin were able to penetrate drug-free membranes. The amount of drug diffused through the membrane correlates with the solubility data. Theophylline, which is insoluble in the matrix system, does not penetrate through a drug-free matrix. Nifedipine is enriched within the matrix because of its high partition coefficient into the matrix material, and therefore, little release is observed. From a drug-containing matrix, theophylline and nifedipine were released according to Higuchi's equation [J. Pharm. Sci. 52:1145–1149 (1963)], although the absolute amount of nifedipine released is limited because of its high solubility in the membrane material. For codeine and indomethacin there was no linear relationship between the amount of drug released and the square root of time. These results agree with the findings for capsules obtained from the gelation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016394815056
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  • 5
    Electronic Resource
    Electronic Resource
    Measures of stochasticity for nonstationary initial preparations of coupled oscillators (1985)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 28 (1985), S. 109-134 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The contributions of different eigenstates of a nonlinearly coupled oscillator system to the expansion of a local wave packet are analyzed from an information theoretical point of view. Such a wave packet can be considered as a nonstationary vibrational state of an electronically excited manifold of a molecule after Franck-Condon type initial preparation. The distributions of these contributions are compared to their individual stochastic ideals using Ruch's concept of “mixing distances.” The stochastic ideals are constructed via a probability diffusion process between neighboring states of the original distributions, representing an initial preparation corresponding to a Hamiltonian with only irregular eigenstates. Gaussian minimum uncertainty wave packets as initial states in a two-dimensional nonlinear oscillator system with classically regular and chaotic energy ranges are studied numerically. It is found that distance measures, partly reflecting the “mixing distance” of a distribution from its stochastic ideal, show a large fluctuation in the classical regular energy range and a small fluctuation in the range where most of the classical trajectories move chaotically. This indicates that for this type of initial preparation process the actual location of the initial state in space plays the dominant role for the dynamics in the low-energy range while for wave packets starting near the dissociation energy of the model system this location becomes unimportant.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560280109
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  • 6
    Electronic Resource
    Electronic Resource
    Quantum dynamics of wave packets on phase space cells in nonlinearly coupled oscillators (1983)
    New York, NY : Wiley-Blackwell
    International Journal of Quantum Chemistry 23 (1983), S. 47-63 
    Details
    ISSN: 0020-7608
    Keywords: Computational Chemistry and Molecular Modeling ; Atomic, Molecular and Optical Physics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The time evolution of harmonic oscillator coherent states (minimum uncertainty wave packet) | Ψμ located on regular and random von Neumann lattice points in phase space is analyzed for nonlinearly coupled anharmonic vibrational systems. The Henon-Heiles system is studied as an example. A quasiprobability measure \documentclass{article}\pagestyle{empty}\begin{document}$ \bar P_{\mu \mu '} $\end{document} is introduced to investigate the relative probabilities for the transition between phase space cells within a narrow energy range. The probability \documentclass{article}\pagestyle{empty}\begin{document}$ \bar P_{\mu \mu '} $\end{document}, as well as the information entropy Sμ, is studied as a function of energy. A smooth transition from regular to chaotic motion is found indicated by a change of the fluctuations of these quantities as a function of energy.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/qua.560230106
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  • 7
    Electronic Resource
    Electronic Resource
    Instrumentierungsmöglichkeiten an RundlauftablettenpressenErweiterte Fassung eines Vortrags auf dem Jahrestreffen der Verfahrens-Ingenieure, 21. bis 23. Sept. 1988 in Hannover. (1989)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 61 (1989), S. 115-123 
    Details
    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
    Notes: Instrumentation of rotary tableting machines. Instrumentation of rotary tableting machines has two main purposes: to control the tableting process during production and to investigate the compression behaviour of substances. While the former is routinely implemented today, the compression process itself is still under investigation. Measurements are carried out to record compression-, ejection-, residual-, die-wall-, and adhesion forces. In addition, displacement of punches is registered. Strain gauges are commonly used for force measurements. For more precise investigations, piezoelectric load washers are installed. Displacement measurements, which are seldom performed on rotary tableting machines, are carried out with inductive displacement transducers. This paper describes the present state of the art. The problems of routine compression force control in tablet production have now been solved. In contrast, a general description of the powdercompression process is not possible in detail. New methods for data collection from rotary tableting machines are described, enabling the pharmacist to reach a better understanding of the compression process.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330610206
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  • 8
    Electronic Resource
    Electronic Resource
    Untersuchungen zum Einfluß der Preß- und Lageratmosphäre auf physikalische Eigenschaften von Tabletten (1998)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 70 (1998), S. 1004-1006 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330700815
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  • 9
    Electronic Resource
    Electronic Resource
    Entwicklung und Konstruktion eines Festigkeitstestgerätes für Tabletten (1997)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 69 (1997), S. 843-846 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330690619
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  • 10
    Electronic Resource
    Electronic Resource
    Untersuchungen zum Einfluß der Preß- und Lageratmosphäre auf die Festigkeit von TablettenTeil eines Vortrags von J. ZIMMER anläßlich der GVC-Fachausschußsitzung „Agglomerations-und Schüttguttechnik“, 2./3. Mai 1994 in Freiberg. (1996)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 68 (1996), S. 116-119 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330680113
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