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  • 11
    Electronic Resource
    Electronic Resource
    Polarized emission from the products of oriented reactants: The Ba+N2O→BaO*+N2 reaction (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5372-5373 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The polarization of the BaO* chemiluminescence from the reaction of oriented N2O with Ba has been studied as a function of the relative collisional orientation at Etr=0.16 eV in a crossed beam apparatus. The dependence of the alignment of BaO* product angular momentum vector Jˆ' upon the initial angle of attack γ0 has been determined. Perfectly oriented reactants (cos γ0=1) produce a strong alignment 〈P2(Jˆ⋅vˆr)〉=−0.3 which becomes practically zero for unfavorable geometries (cos γ0≤−0.5).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451682
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  • 12
    Electronic Resource
    Electronic Resource
    Nematic–lamellar tricritical behavior and structure of the lamellar phase in the ammonium pentadecafluorooctanoate (APFO)/water system (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 9096-9105 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: 2H NMR spectroscopy has been used to map a high-resolution (±0.04 K) phase diagram for the ammonium pentadecafluorooctanoate(APFO)/heavy water system. It is qualitatively similar to that for the CsPFO/heavy water system. In particular, it exhibits a discotic micellar nematic phase N+D intermediate to an isotropic micellar solution phase I and a lamellar phase for weight fractions of APFO between 0.395 (φ=0.278) and 0.589 (φ=0.455) and temperatures between 292.10 and 338.10 K. The N+D to lamellar transition crosses over from second to first order behavior at a tricritical point similar to the superfluid transition in 3He/4He mixtures. X-ray scattering experiments shows there to be no dramatic change in the structure of the micelle at the I to N+D and the N+D to lamellar transitions. Nematic order parameters (orientational order parameters of the discoidal micelles) have been calculated from electrical conductivity measurements. Their variation with temperature in the nematic phase and across the nematic to lamellar transition are qualitatively consistent with the behavior expected for thermotropic calamitic liquid crystals undergoing an isotropic to nematic to smectic-A sequence of transitions.It is, therefore, concluded that the transition from the N+D to the lamellar phase solely involves the propagation of long range positional ordering of the discoidal micelles into planes along the nematic director, that is, the lamellar phase is a discotic lamellar phase LD. This result reinforces previous claims about the structure of the lamellar phase of the CsPFO system as opposed to the alternative scenario of a classical lamellar phase in which the bilayers are perforated by microscopic defects. This conclusion is supported by measurements of 2H quadrupole splittings of heavy water. Similar measurements for deuterated ammonium ions show a preference for counterion binding to sites of lowest surface curvature. The fraction of counterions bound to the surface of the micelle is shown to increase as the temperature is lowered due to a growth in diameter and associated changes in surface curvature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.459200
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  • 13
    Electronic Resource
    Electronic Resource
    Coupled nonlinear Schrödinger equations arising in the study of monomode step-index optical fibers (1989)
    College Park, Md. : American Institute of Physics (AIP)
    Journal of Mathematical Physics 30 (1989), S. 930-936 
    Details
    ISSN: 1089-7658
    Source: AIP Digital Archive
    Topics: Mathematics , Physics
    Notes: In this paper it is shown that nonlinear propagation in a step-index, "monomode'' optical fiber is not generally governed by the nonlinear Schrödinger equation, even when the fiber is axially symmetric. It is governed by a coupled pair of nonlinear partial differential equations that includes the nonlinear Schrödinger equations only as a special case. Three simple types of solution to the coupled system are analyzed and the corresponding field patterns are interpreted. One case shows that, for uniform wavetrains, nonlinearity not only alters the phase speed but also causes the field pattern in an "elliptically polarized'' mode to rotate gradually about the fiber axis. The other two cases each allow the system to be reduced to a single nonlinear Schrödinger equation, so showing two distinct situations in which solutions have soliton properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.528360
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  • 14
    Electronic Resource
    Electronic Resource
    Photophysics of O2 excited by tunable laser radiation around 193 nm (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 4037-4044 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photodissociation/ionization dynamics of O2 around 193 nm have been studied using a narrowband tunable ArF excimer laser and the velocity map imaging technique. Angular and kinetic energy distributions of the product O+ ions and O(3P2) atoms are recorded and analyzed. The production of O(3P2) atoms is resonance enhanced on the one-photon level by the B 3Σu−(v=4) state, which is part of the B 3Σu−←X 3Σg− Schumann–Runge bands. Angular distribution measurements for individual rotational levels of the B state yield values for the anisotropy parameter, βSR, which are in good agreement with the values predicted by independent measurements of predissociation lifetimes from spectral linewidths. An average value of β=0.48 is found for the underlying Herzberg continuum at 193 nm. O2+ production is enhanced on the two-photon level via members of the nsσg(n−1)dπg1Σg+ Rydberg series terminating at higher vibrational levels of the ion. The high Rydberg states autoionize into the O2+ X 2Πg ground state or absorb one more photon and then autoionize into the A 2Πu and b 4Σu− states of O2+, which subsequently fluoresce. Production of O+ from one- and two-photon dissociation of the O2+ formed after two-photon absorption is also observed and characterized. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.480953
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  • 15
    Electronic Resource
    Electronic Resource
    Photodissociation–ionization dynamics of molecular chlorine Rydberg states using velocity map imaging (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 1205-1212 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Velocity map images are reported for photoelectrons and atomic chlorine ions produced during one-color REMPI (resonance enhanced multiphoton ionization) of molecular chlorine via the v=0–15 vibrational levels of the 2 1Πg(4s) Rydberg state. Previous magnetic bottle photoelectron studies by Koenders et al. of the same process have shown that REMPI proceeds by two-photon resonant excitation, followed by core-excitation to a super-excited Rydberg state at the three-photon level. This state undergoes (auto)-ionization, resulting in the formation of ground-state molecular chlorine ions, and/or dissociation to neutral products, resulting in the production of electronically excited neutral chlorine atoms. Photoelectrons arise from ionization of Cl2 and electronically excited Cl atoms, while Cl+ ions arise from the dissociation of Cl2+ and from ionization of the excited Cl atoms. The chlorine ion velocity map images reveal new information on the dissociation–ionization dynamics of superexcited Cl2 and the dissociation dynamics of the subsequently formed Cl2+ ions. In the latter case an unexpected low-energy Σ←Π (perpendicular) dissociation pathway to Cl+(1D)+Cl(3P) product atoms is observed. Results from the photoelectron images are compared with those from the magnetic bottle studies. While the imaging kinetic-energy resolution is less than that of the magnetic bottle spectrometer, the angular distribution information and lack of velocity bias of imaging is advantageous. Most of the trends observed in the electron and Cl+ images can be rationalized in terms of single-electron excitation processes and the known molecular orbital structure of the electronic states involved. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1375028
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  • 16
    Electronic Resource
    Electronic Resource
    Completely inverted ClO vibrational distribution from OClO(2A2 24,0,0) (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 5298-5300 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The gas phase dissociation dynamics of symmetric chlorine dioxide highly photoexcited into its 2A2 24,0,0 vibronic level has been investigated by monitoring both the kinetic energy release and the angular distribution of the O(3P2) products via velocity map imaging. The resulting O(3P2) kinetic energy profile provides full the vibrational distribution of the formed ClO(X 2Π,v) radicals. The measured O fragment kinetic energy distribution reflects an unprecedented nonstatistical vibrational state population of their diatomic partners, where the excess energy is focused only in the three highest possible ClO vibrational levels v=18–20, with little fragment rotation. The anisotropy of the dissociation process sheds new light on the fragmentation dynamics of this stratospherically relevant triatomic molecule. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481100
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  • 17
    Electronic Resource
    Electronic Resource
    Economic Regulation: a review of issues (2002)
    Oxford, UK and Boston, USA : Blackwell Publishers Ltd.
    Annals of public and cooperative economics 73 (2002), S. 0 
    Details
    ISSN: 1467-8292
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: This article surveys a range of issues relating to economic regulation. It begins by examining market and state failures which provide the basis for arguments in support of regulation. Concentrating on natural monopolies, the article outlines the main forms of economic regulation, namely rate–of–return or cost–of–service regulation, price–cap regulation, and sliding scale regulation, a hybrid between price–cap and rate–of–return approaches. Reference is made to the broad phases that need to be considered in the evolution of natural monopoly regulation. These are concerned with regulating the incumbent monopoly, promoting and policing the development of competition, and maintaining competition once it has been introduced. The last phase may be better served through the use of effective national competition laws rather than dedicated sector regulation. The article also examines the range of factors that are likely to affect the economic efficiency and effectiveness of regulation. These involve a mixture of economic, political and governance conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/1467-8292.00202
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  • 18
    Electronic Resource
    Electronic Resource
    Serum albumin and CA125 are powerful predictors of survival in epithelial ovarian cancer (1994)
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 101 (1994), S. 0 
    Details
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objective To assess the prognostic significance of presentation serum albumin, clinical stage and CA125 levels in ovarian cancer.Design Retrospective analysis of data using a Cox proportional hazards model.Setting A district general hospital oncology unit.Subject One hundred and fourteen consecutive patients with epithelial ovarian cancer.Interventions Cytotoxic chemotherapy and surgery.Main outcome measure Survival.Results A linear increase in risk was observed with high log CA125 (P 〈 0.0001) and with low albumin (P 〈 0.0001). In late stage patients (III and IV) albumin is the best predictor of survival (P= 0.0006). The presence of ascites, blood transfusion, type of surgery or chemotherapy did not improve the predictive model.Conclusions CA125 and albumin can be used to identify prognostic subgroups independently of stage. Albumin alone can also be used as a predictor of survival. A simple classification of patients into three groups based on serum albumin of 41 g/l or more, 35 to 40 g/l and 34 g/l or less provides a clear separation of survival curves in the present group of patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-0528.1994.tb13550.x
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  • 19
    Electronic Resource
    Electronic Resource
    Coefficient of expansion of gallium arsenide from –62 to 200°C (1966)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 21 (1966), S. 290-290 
    Details
    ISSN: 0001-5520
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0365110X66002780
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  • 20
    Electronic Resource
    Electronic Resource
    The Effects of Unidirectional Visual Surround Translation on Detection of Physical Linear Motion Direction: A Psychophysical Scale for Vection (1992)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 656 (1992), 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.1749-6632.1992.tb25262.x
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