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  • 1
    Electronic Resource
    Electronic Resource
    Line shifts and broadenings in polarizable liquids (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 91 (1989), S. 340-349 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We present a new dynamical derivation of the approximation used by Thompson, Schweizer, and Chandler and by Høye and Stell for the frequency dependent polarizability of a quantum fluid with harmonically bound dipole moments; the Drude model. The derivation is the same for classical and quantum liquids—as is of course the result which agrees with that of these authors. We then refine the theory by taking account of the limited number of energy levels available, i.e., we replace the harmonic approximation by a two level approximation, for the target atom. This leads to a prefactor ω0I/ω0 in the line shift of an impurity atom in a fluid computed by Chandler, Schweitzer, and Wolynes: ω0 and ω0I being the characteristic frequencies of the fluid and impurity atoms, respectively. This factor improves the agreement between theory and experiment, especially those of Nowak and Bernstein on benzene in argon and some other liquids. We also compute the line shapes of the impurity atom by Monte Carlo simulations and obtain reasonable agreement with experimental observations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.457466
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  • 2
    Electronic Resource
    Electronic Resource
    Organoiron approach to 3,14-dihydroxytrichothecenes (1986)
    s.l. : American Chemical Society
    The @journal of organic chemistry 51 (1986), S. 1939-1947 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00361a001
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  • 3
    Electronic Resource
    Electronic Resource
    Iptycene synthesis. A new method for attaching a 2,3-anthracene moiety to the 9,10-positions of another anthracene moiety. Exceptional conditions for a Lewis acid-catalyzed Diels-Alder reaction (1989)
    s.l. : American Chemical Society
    The @journal of organic chemistry 54 (1989), S. 2612-2615 
    Details
    ISSN: 1520-6904
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jo00272a030
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    THE NONCOVALENT COUPLING OF RHODOPSIN and PHOSPHATIDYLCHOLINES (1973)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 222 (1973), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1973.tb15284.x
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  • 5
    Electronic Resource
    Electronic Resource
    Macroscopic quantum tunneling in a dc SQUID (1986)
    Springer
    Journal of low temperature physics 65 (1986), S. 133-147 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The theory of macroscopic quantum tunneling is applied to a current-biased dc SQUID whose dynamics can be described by a two-dimensional mechanical system with a dissipative environment. Based on the phenomenological model proposed by Caldeira and Leggett, the dissipative environment is represented by a set of harmonic oscillators coupling to the system. After integrating out the environmental degrees of freedom, an effective Euclidean action is found for the two-dimensional system. The action is used to provide the quantum tunneling rate formalism for the dc SQUID. Under certain conditions, the tunneling rate reduces to that of a single current-biased Josephson junction with an adjustable effective critical current.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685404
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  • 6
    Electronic Resource
    Electronic Resource
    Lens effect on synthetic image generation based on light particle theory (1987)
    Springer
    The visual computer 3 (1987), S. 125-136 
    Details
    ISSN: 1432-2315
    Keywords: Computer graphics ; Synthetic image generation ; Lens effect ; Blurry image ; Light particle theory ; Camera model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The synthetic image generation with the lens effect consists of two consecutive processors: the hidden-surface processor, and the focus processor. The normal ray-tracing algorithms are used in the first processor. The second processor computes Lommel's function, which is an infinite series of Bessel functions. In order to avoid the complicated calculation and the huge memory consumption, an approximation method based on the light particle theory is developed. No noticeable differences can be detected between the results from the approximation method and those from the exact calculation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01962893
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  • 7
    Electronic Resource
    Electronic Resource
    Theory of quantum dynamics in fermionic environment: An influence functional approach (1987)
    Springer
    Journal of statistical physics 47 (1987), S. 17-55 
    Details
    ISSN: 1572-9613
    Keywords: Path integral ; influence functional ; fermion bath ; real-time density matrix ; Grassmann algebra ; quantum Langevin equation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Quantum dynamics of a particle coupled to a fermionic environment is considered, with particular emphasis on the formulation of macroscopic quantum phenomena. The framework is based on a path integral formalism for the real-time density matrix. After integrating out of the fermion variables of the environment, we embed the whole environmental effects on the particle into the so-called influence functional in analogy to Feynman and Vernon's initial work. We then show that to the second order of the coupling constant, the exponent of the influence functional is in exact agreement with that due to a linear dissipative environment (boson bath). Having obtained this, we turn to a specific model in which the influence functional can be exactly evaluated in a long-time limit (long compared to the inverse of the cutoff frequency of the environmental spectrum). In this circumstance, we mainly address our attention to the quantum mechanical representation of the system-plus-environment from the known classical properties of the particle. It is shown that, in particular, the equivalence between the fermion bath and the boson bath is generally correct for a singlechannel coupling provided we make a simple mapping between the nonlinear interaction functions of the baths. Finally, generalizations of the model to more complicated situations are discussed and significant applications and connections to certain practically interesting problems are mentioned.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01009034
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  • 8
    Electronic Resource
    Electronic Resource
    A new method for quantum processes in fermionic heat baths (1987)
    Springer
    Journal of statistical physics 49 (1987), S. 811-826 
    Details
    ISSN: 1572-9613
    Keywords: Adiabatic transformation ; fermion bath ; Grassmann algebra ; influence functional ; path integral ; real-time density matrix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The general path-integral formalism for real-time dynamics for a quantum system in a fermionic environment proposed previously is investigated by using a new method called local adiabatic transformation. This method is based on the observation that in the long-time limit (the time scale of the system is much larger than that of the environment, typically characterized by the inverse of the cutoff frequency of the environment), most degrees of freedom of the environment will follow the dynamics adiabatically. This feature is utilized by transforming the original problem of coordinate coupling into a problem of velocity coupling. This is achieved by making some simple unitary transformation on the fermion field (before path-integrating out of that field). By doing perturbations on the new problem, all the previous important results are recovered. Further-more, generalizations to more realistic situations [for example, a particle traveling over a large distance and coupled to a Fermi gas through the phase factor exp(ik·R) (the coupling may involve many channels of angular momentum)] are considered and significant results obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01009357
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  • 9
    Electronic Resource
    Electronic Resource
    Photocrosslinking of polyethylene. I. Photoinitiators, crosslinking agent, and reaction kinetics (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 4051-4075 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High density polyethylene has been photocrosslinked in the melt by using 4-chlorobenzophenone (4-CBP) as photoinitiator and triallylcyanurate (TAC) as crosslinking agent. Various factors affecting the crosslinking process (photoinitiator used and its concentration, irradiation temperature and time, atmosphere, UV light source, light intensity) were examined. By optimizing the irradiation conditions, it was found that samples up to 2 mm thick could readily be crosslinked to high gel content (≈ 90%) with satisfactory homogeneity within very short irradiation times (≈ 15 s). The kinetic analysis of the crosslinking process showed a linear relation between log S and log t (S is the sol fraction t is the irradiation time). An induction period was observed, the length of which decreased with increasing concentration of 4-CBP and increasing light intensity. An upper limit of gel content was also found for long irradiation times at a level depending on the concentration of 4-CBP. The crosslinking rate was proportional to the second order of light intensity at lower intensity and changed to first order at higher light intensity. A mechanism based on the recombination of chain radicals through both allyl and alkyl type radicals of TAC was proposed.
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080271214
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  • 10
    Electronic Resource
    Electronic Resource
    Photocrosslinking of polyethylene. II. Properties of photocrosslinked polyethylene (1989)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 27 (1989), S. 4077-4086 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Some properties of photocrosslinked high density polyethylene (2 mm thick sheets) have been studied. The homogeneity of the network is greatly improved by the application of triallylcyanurate (TAC) as crosslinking agent. The role of TAC in promoting the crosslinking is discussed. The crosslinked PE is found to be durable towards immersion in boiling water. Oxygen permeability increases while density and melting point decrease with increasing degree of crosslinking. The network chain density is obtained using conventional swelling method in boiling xylene, which together with data from melting point depression show that contribution of chain entanglement is insignificant to the gel formation of PE in this work.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1989.080271215
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