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  • 1
    Electronic Resource
    Electronic Resource
    Sudden representation and sudden approximation quantal generalized master equation (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 1750-1757 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The application of the sudden approximation in the derivation of a quantal generalized master equation (GME) is examined. Two different types of physical systems are considered. One is a composite system comprised of a fast primary system and slow bath compared to the time the former is coupled to the latter. The other is a composite system comprised of a slow primary system and fast bath. The resulting sudden GME's for both cases contain non-Markovian memory kernels. In the second case, the memory kernel can be further approximated by a Markovian form. The resulting Markovian-sudden GME is identical to the GME obtained by using the adiabatic elimination method for removing the (fast) stochastic bath coordinates. Using a representation of the Schrödinger propagator for the density operator analogous to the recently developed (energy) sudden representation of the Schrödinger propagator for the wave function, the exact GME is recast into a form such that when the memory kernel and the inhomogeneity term of the equation are expanded in a perturbation series, the zeroth order equation is in the sudden approximation form. Finally, a harmonic oscillator coupled linearly to a bath of harmonic oscillators is used as an illustration. The behavior of the bath correlation functions in the Markovian and the sudden limits is examined. The reduction of the exact GME to the sudden approximation form is also considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449363
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  • 2
    Electronic Resource
    Electronic Resource
    General factorization relations and consistency conditions in the sudden approximation via infinite matrix inversion (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 1637-1647 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Local, i.e., multiplicative, operators satisfy well-known linear factorization relations wherein matrix elements (between states associated with a complete set of wave functions) can be obtained as a linear combination of those out of the ground state (the input data). Analytic derivation of factorization relations for general state input data results in singular integral expressions for the coefficients, which can, however, be regularized using consistency conditions between matrix elements out of a single (nonground) state. Similar results hold for suitable "symmetry class'' averaged matrix elements where the symmetry class projection operators are "complete.'' In several cases where the wave functions or projection operators incorporate orthogonal polynomial dependence, we show that the ground state factorization relations have a simplified structure allowing an alternative derivation of the general factorization relations via an infinite matrix inversion procedure. This form is shown to have some advantages over previous versions. In addition, this matrix inversion procedure obtains all consistency conditions (which is not always the case from regularization of singular integrals).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449401
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  • 3
    Electronic Resource
    Electronic Resource
    Path integral approach to multiparticle systems: The sudden representationf a@f ) (1985)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 83 (1985), S. 680-687 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The recently developed (energy) sudden representation of the Schrödinger propagator is examined in conjunction with the path integral method. The perturbation expansion of the propagator in this representation (with the sudden approximation as the zeroth order term) is easily understood using Feynman diagrams. The zeroth order term is a form involving only sudden paths (i.e., paths resulting from the sudden approximation). Each higher order term is a series of sudden paths which are connected to one another due to the nonsudden effects of the dynamics. The sudden representation, and in particular its perturbation expansion, is also used to study the bath effects in many body systems which are expressed in the form of influence functionals in the path integral formalism. In our treatment, the bath coordinates are assumed to be the slow coordinates. The zeroth order (sudden approximation) influence functionals are expressed in a very simple form; they involve only an ordinary integral over the bath coordinates. Finally, to illustrate the approach, a harmonic oscillator coupled linearly to an unspecified primary system is used as a simple model bath. The reduction of the exact influence functional to the sudden approximation form is also considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.449537
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  • 4
    Electronic Resource
    Electronic Resource
    Initial electron transfer in photosynthetic reaction centers of Rhodobacter capsulatus mutants
    Amsterdam : Elsevier
    Chemical Physics Letters 176 (1991), S. 366-372 
    Details
    ISSN: 0009-2614
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0009-2614(91)90045-B
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  • 5
    Electronic Resource
    Electronic Resource
    Simple overshoot-suppressed digital proportional-integral-derivative temperature controller (1988)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 59 (1988), S. 1001-1003 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This note describes a simple but efficient algorithm for a digital PID temperature controller. A special reset mechanism is implemented to suppress the inevitable overshoot in a PID controller.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1139785
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  • 6
    Electronic Resource
    Electronic Resource
    Coherent radiative control of IBr photodissociation via simultaneous (ω1,ω3) excitation (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 94 (1991), S. 2688-2696 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We show that simultaneous one- and three-photon photodissociation of IBr can be used to control the relative product yield of ground and excited state Br atoms. The control attained is substantial insofar as it is possible to vary the Br* yield over the range of 25%–95%, even for a high J case which involves extensive averaging over MJ states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459843
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  • 7
    Electronic Resource
    Electronic Resource
    Measurement of the shape of a liquid-liquid interface by the method of light reflection (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 632-637 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: An apparatus has been developed to measure the shape of the liquid-liquid interface of a phase-separated binary mixture after a temperature quench. The working principle of the apparatus is to measure the shape of the interface by using the reflection of a scanning light beam to find out the slope of the interface at various positions, and then the shape of the interface is obtained by a numerical integration. A real-time display sensitive to the shape of the interface is also provided to facilitate alignment of the optics. Results from calibrations show that a vertical resolution of 1 μm over a horizontal distance of 5 cm can easily be attained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144189
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  • 8
    Electronic Resource
    Electronic Resource
    Temperature-dependent resonance Raman profiles of β-carotene in carbon disulfide (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 84 (1986), S. 2497-2502 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Resonance Raman (RR) profiles of the 1005, 1155, and 1525 cm−1 modes of β-carotene dissolved in carbon disulfide have been measured at room temperature and at 172 K. Previous studies, based upon room temperature measurements, have indicated that inhomogeneous (i.e., site) broadening may be important for this system. Our measurements are the first RR data for this system at two temperatures. Such data are necessary in order to study the relative importance of inhomogeneous broadening and thermal broadening. Using previously developed transform techniques, we analyze our RR data by calculating profile line shapes directly from our measured optical absorption data for each temperature. The assumptions underlying this analysis do not include inhomogeneous broadening, and the calculations yield profile line shapes which are in quite good overall agreement with the measured profile line shapes for all three modes at both temperatures. We have also extended the transform calculations in order to incorporate inhomogeneous broadening. However, the agreement between the measured and calculated RR profile line shapes is not substantially improved by the inclusion of inhomogeneous broadening in the transform analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450369
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  • 9
    Electronic Resource
    Electronic Resource
    Extracellular expression of human epidermal growth factor encoded by an Escherichia coli K-12 plasmid stabilized by the ytl2-incR system of Salmonella typhimurium (1998)
    Springer
    Journal of industrial microbiology and biotechnology 21 (1998), S. 31-36 
    Details
    ISSN: 1476-5535
    Keywords: Keywords: hEGF; plasmid pSLT; ytl2-incR stabilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A plasmid stabilization system, active in high copy-number plasmids, was cloned from the large resident plasmid, pSLT, of Salmonella typhimurium. The ytl2 gene, together with a 249-bp region (termed incR) downstream of the gene, imparted 〉104-fold stability to a pBR322-based plasmid. The ytl2-incR region was then used to stabilize a recombinant plasmid carrying the human epidermal growth factor gene (with the Escherichia coli K-12 ompA signal sequence), behind the lacUV5 promoter. In shake flask tests to optimize expression of human epidermal growth factor, loss of recombinant plasmid was 〈1% when growth (both before and after induction with isopropyl-β-d-galactopyranoside) took place even in the absence of antibiotic selection, and the specific activity of secreted human epidermal growth factor was ca 20 μg per 108 cells at harvest, compared to a figure of ca 3 μg per 108 cells when a comparable plasmid, but devoid of the ytl2-incR region, was employed, as outgrowth of plasmid-free cells after induction severely compromised the specific activity of the secreted product.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/sj.jim.2900557
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  • 10
    Electronic Resource
    Electronic Resource
    Laser fluorimetry studies of ionpair aggregation in ionomers derived from copolymers and polymer containing 2-vinylfluorene (1987)
    Springer
    Polymer bulletin 17 (1987), S. 375-381 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary Time resolved fluorescence technique was used to demonstrate physically the ionpair aggregation phenomena in the ionomers containing fluorenylsodium as the pendant group along the polymer chains in THF at 25°C. It was found that ionpairs in the ionomer with mole fraction of fluorenylsodium equal to 0.02 did not associate to form stable aggregate. However, the ionpairs would aggregate in those ionomers with higher fluorenylsodium contents. In the homopolymer of vinylfluorenylsodium, extensive aggregation of the ionpairs was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00955723
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