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  • 1
    Electronic Resource
    Electronic Resource
    Transverse diffusion measurements and comparisons with Monte Carlo simulation and Gram–Charlier calculations for Cs+ ions drifting in He gas (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 9547-9550 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The ratio of the transverse diffusion coefficient to the mobility, DT/K, has been experimentally determined for Cs+ ion drifting in He gas at E/N (electric field to neutral gas number density ratio) values ranging from 5 to 140 Td. Results at 303 K are reported with an overall accuracy of ±4%. The DT/K results were effectively corrected for longitudinal end effects existing in the drift tube. In addition, Monte Carlo simulation (MCS) calculations were made for the mobility and transport coefficients using the Koutselos, Mason, and Viehland (KMV) interaction potential as input. Comparisons of MCS results and available kinetic theory's Gram–Charlier results with the present and previous experimental data give an indication of the validity and accuracy of the present potential. The theoretical results did not reproduce the experimental curve very well, suggesting that the proposed potential for the Cs+–He pair should be modified. Further comparisons of the transverse and longitudinal diffusion coefficients indicate that the Gram–Charlier approach of kinetic theory is quite accurate even for the large ion-neutral mass ratio. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.473855
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  • 2
    Electronic Resource
    Electronic Resource
    Thermionic aluminosilicate sources of Tl+ ions (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 5249-5251 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Thermionic filament sources of Tl+ ions were made using tungsten wire coated with synthetic thallium aluminosilicates in the β-eucryptite (Tl2OAl2O32SiO2) and two other compositions (2Tl2OAl2O32SiO2 and 2Tl2OAl2O34SiO2). Three different methods for the production of aluminosilicate melts were used. The performance characteristics as thermionic emission sources of Tl+ ions based on total emission current and purity of ion emission as functions of time and filament surface temperature were studied and compared. Our results indicated that the sample of composition ratio of 2Tl2OAl2O32SiO2, which was produced by resistance heating under atmospheric pressure in air, is an optimum Tl+ ion source at temperatures between 1150 and 1350 °C after 150 h of continuous heating. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1146093
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  • 3
    Electronic Resource
    Electronic Resource
    Oxides as thermionic sources of Mg+, Ca+, Sr+, and Ba+ ions (1995)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 66 (1995), S. 2879-2882 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Group II metal oxides (MgO, CaO, SrO, and BaO) were coated on tungsten or tantalum filaments to form thermionic emitters of positive metal ions. The choice between tungsten and tantalum for optimum performance was empirically found to depend on the oxide material. Total ion emission current and ion purity were generally found to increase with temperature. A stable source of high purity (up to 97%) Ba+ ions could be obtained from the BaO-coated filament at 1800 °C after 150 min of heating. At 1600 °C, the SrO-coated filament could produce a relatively stable ion current and purity of 97% of Sr+ ions. Very pure (99.8%) Ca+ ions were emitted at 1950 °C. However more stable ion current though less pure ions (87% of Ca+ at 1800 °C) were obtained at lower temperatures. MgO-coated filaments using tungsten or tantalum wires were found to be unsuitable as a source of Mg+ ions. All the filaments of MgO, CaO, SrO, and BaO were found to produce larger ion current and higher ion purity at higher temperatures. In general, the relative isotopic abundances of ions produced by a thermionic source are reproduced by the natural isotopic abundances of the corresponding metal. It implies that the slight differences in the nuclear masses of the isotopes do not introduce any significant effect on their ion production efficiency. Between tantalum and tungsten as a choice for the filament material, tantalum was found to be a better choice for Ba+ and Sr+ ions, while tungsten was better for Ca+. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1145572
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  • 4
    Electronic Resource
    Electronic Resource
    Uncoupling of the calcium-induced terminal differentiation and the activation of membrane-associated transglutaminase in murine keratinocytes by type-β transforming growth factor
    Amsterdam : Elsevier
    Experimental Cell Research 183 (1989), S. 101-111 
    Details
    ISSN: 0014-4827
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0014-4827(89)90421-7
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  • 5
    Electronic Resource
    Electronic Resource
    A first example of catalytic ylide epoxidation reaction: facile synthesis of vinyl epoxides from aldehydes catalyzed by diisobutyl telluride
    Amsterdam : Elsevier
    Tetrahedron Letters 31 (1990), S. 7657-7660 
    Details
    ISSN: 0040-4039
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0040-4039(00)97324-6
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  • 6
    Electronic Resource
    Electronic Resource
    Reactions of diazocompounds with carbonyl compounds mediated by diorganyl telluride and catalytic amount of CuI compounds: conversion of aldehydes to a
    Amsterdam : Elsevier
    Tetrahedron 49 (1993), S. 6821-6830 
    Details
    ISSN: 0040-4020
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0040-4020(01)80425-7
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  • 7
    Electronic Resource
    Electronic Resource
    A first non-stabilized telluronium ylide - diphenyltelluronium methylide as a novel reagent for synthesis of oxlranes
    Amsterdam : Elsevier
    Tetrahedron Letters 31 (1990), S. 4173-4174 
    Details
    ISSN: 0040-4039
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0040-4039(00)97573-7
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  • 8
    Electronic Resource
    Electronic Resource
    Trajectory planning and control of a Stewart platform-based end-effector with passive compliance for part assembly (1992)
    Springer
    Journal of intelligent and robotic systems 6 (1992), S. 263-281 
    Details
    ISSN: 1573-0409
    Keywords: Trajectory planning ; Stewart platform ; parallel manipulator ; passive compliance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper presents the kinematic analysis and trajectory planning for a six-degrees-of-freedom end-effector whose design is based on the Stewart platform mechanism. The end-effector is composed of two platforms and six linear actuators driven by stepper motors. A spring-loaded platform is used to provide passive compliance to the end-effector during a part assembly. A closed-form solution is derived for the inverse kinematic transformation and a computationally effective numerical solution is obtained for the forward kinematic transformation using the Newton-Raphson method. Three trajectory planning schemes, two for fine motion and one for gross motion are developed. Experimental results of tracking various test paths are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00248019
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  • 9
    Electronic Resource
    Electronic Resource
    Zeeman transitions in deuterium atoms induced by ultra-relativistic electrons (1997)
    Springer
    Hyperfine interactions 110 (1997), S. 239-257 
    Details
    ISSN: 1572-9540
    Keywords: hyperfine transitions ; deuterium ; ultra-relativistic electrons ; polarization ; atomic beam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We present data showing hyperfine transitions in an atomic deuterium beam induced by the (476 MHz) radio-frequency field of a 704 MeV electron beam in a storage ring. A polarized deuterium beam, produced in an atomic beam source, was crossed with a stored electron beam and analyzed with a Breit--Rabi polarimeter. Electron-beam induced transitions were singled out by injecting different combinations of hyperfine states. Transition probabilities as high as 70% were measured at large currents (~ 100 mA). All possible deuterium transitions for a radio-frequency of 476 MHz were observed. In addition, a 1--6 transition resulting from the first harmonic (952 MHz) was observed. The effects of these transitions are of general importance for the polarized internal target technique applied in nuclear and particle physics experiments. The data are reasonably described by numerical estimates. The observed mechanism can be exploited to create nuclear polarized atoms when injecting electron polarized atoms with no net nuclear polarization into a storage cell. However, when nuclear polarized atoms are injected, care should be taken to avoid this mechanism, since it would result in depolarization of the atoms. The studies enabled us to choose the magnetic guide field during our spin-dependent electron--deuteron scattering experiments, such that electron-beam induced depolarizing effects were avoided.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1012696020930
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  • 10
    Electronic Resource
    Electronic Resource
    Compatibilization of the polystyrene/poly(ethyl acrylate) and polystyrene/polysoprene systems through ionic interactionsThis article is a review of work recently reported in the Journal of Polymer Science. (1982)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 22 (1982), S. 1117-1122 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    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: Interactions between anions on one polymer chain with cations on another can lead to compatibilization of otherwise incompatible materials. Thus, if 5 mol% of ∼SO3H groups are attached to polystyrene, and 5 mol% of vinyl pyridine is copolymerized with ethyl acrylate, proton transfer occurs upon mixing, and the pairwise attractive interactions between the resultant ions compatibilize the blend. The same has been observed for the styrene-vinyl pyridine and sulfonated polyisoprene polymer pair. Dynamic mechanical and optical properties are used as a measure of compatibilization.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760221711
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