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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 6669-6673 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have measured the temperature and electric field dependence of the direct current (dc) electrical resistivity of several electro-optic polymers, in addition to pure polymethyl methacrylate (PMMA) and a commercial acrylate, UV-15. All the polymers exhibit a decrease in resistivity, to different degrees, with increasing temperature between room temperature and 130 °C. The results show that in a sandwich of multiple layers, the high temperature resistivity mismatch between individual layers results in field concentration in the layer with the highest electrical resistivity. This can be used to explain the enhanced electro-optic coefficient measured in electro-optic devices consisting of a sandwich of UV-15/copolymer/UV-15. In PMMA, we observed a saddle region in the temperature dependence of resistivity between 67 and 78 °C. Outside the saddle region, the resistivity of PMMA follows an Arrhenius relationship, with an activation energy of 1.0 eV. This saddle region is broadened in the nitro and DCV copolymers. A mechanism in which the motion of side chains hinders the interchain hopping of conducting species is proposed to explain our data.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 1800-1802 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electro-optic phase modulation was measured along with optical second-harmonic generation in thin films of a new copolymer containing a dicyanovinyl-terminated azo dye side chain. Orientational order was imparted to these films by poling with a corona discharge. Details of the electro-optic measurement technique, in which the real part of the electro-optic coefficient can be determined directly, are presented. Taking advantage of the increased orientation imparted by corona poling and the hindered motion of the nonlinear optical moiety in the side chain of the polymer leads to substantial improvements in both the magnitude and stability of nonlinear optical susceptibilities compared to guest-host polymer systems ordered by electrode poling.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 308 (1984), S. 698-705 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The general circulation of the oceans is determined by vorticity, temperature and salinity. The theory of large-scale circulation puts a strong constraint on the fields of potential vorticity, q. New calculations and observations of the North Atlantic and North Pacific, using the field of potential ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 29 (1989), S. 1205-1208 
    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: Emerging guided-wave integrated optical technologies require suitable active devices and optical interconnects. Certain organic molecular materials possess the required optical nonlinearities for application in active devices. Glassy polymers, such as poly(methyl methacrylate), have been used to fabricate high optical quality passive structures. For application in integrated optics, requirements include high optical quality (low scattering and absorption losses), low dielectric constant, and suitable fabrication techniques.We describe the preparation and optical properties of a new material, class, poled polymer glasses, which combines the attractive properties of the optical nonlinearities of organic molecules and the optical quality of polymer glasses. These materials are formed by incorporating organic compounds possessing large optical nonlinearities into a host material lacking long-range order. The orientational order is imparted to the composite system by applying a strong electric field at a temperature above the glass transition temperature, where molecular motion is enhanced, thereby aligning the optically nonlinear dopant molecules. By cooling the material through the phase transition with the field still applied, the orientational order is frozen in, and the composite material possesses second-order nonlinear optical properties.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
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    Woods Hole Oceanographic Institution
    In:  In: The North Atlantic Current System: a scientific report. , ed. by Malanotte-Rizzoli, P. and Rossby, T. Woods Hole Oceanographic Institution, Woods Hole, MA, USA, pp. 53-64.
    Publication Date: 2020-05-08
    Type: Book chapter , PeerReviewed
    Format: text
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  • 7
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    Unknown
    AMS (American Meteorological Society)
    In:  Journal of Physical Oceanography, 26 . pp. 1142-1164.
    Publication Date: 2020-08-04
    Description: The authors use different versions of the model of the wind- and thermohaline-driven circulation in the North and Equatorial Atlantic developed under the WOCE Community Modeling Effort to investigate the mean flow pattern and deep-water formation in the subpolar region, and the corresponding structure of the basin-scale meridional overturning circulation transport. A suite of model experiments has been carded out in recent years, differing in horizontal resolution (1° × 1.2°, 1/3° × 0.4°, 1/6° × 0.2°), thermohaline boundary conditions, and parameterization of small-scale mixing. The mass transport in the subpolar gyre and the production of North Atlantic Deep Water (NADW) appears to be essentially controlled by the outflow of dense water from the Greenland and Norwegian Seas. in the present model simulated by restoring conditions in a buffer zone adjacent to the boundary near the Greenland–Scotland Ridge. Deep winter convection homogenizes the water column in the center of the Labrador Sea to about 2000 m. The water mass properties (potential temperature about 3°C, salinity about 34.9 psu) and the volume (1.1×1053 km3) of the homogenized water are in fair agreement with observations. The convective mixing has only little effect on the net sinking of upper-layer water in the subpolar gyre. Sensitivity experiments show that the export of NADW from the subpolar North Atlantic is more strongly affected by changes in the overflow conditions than by changes in the surface buoyancy fluxes over the Labrador and Irminger Seas, even if these suppress the deep convection completely. The host of sensitivity experiments demonstrates that realistic meridional overturning and heat transport distributions for the North Atlantic (with a maximum of 1 PW) can be obtained with NADW production rates of 15–16 Sv, provided the spurious upwelling of deep water that characterizes many model solutions in the Gulf Stream regime is avoided by adequate horizontal resolution add mixing parameterization.
    Type: Article , PeerReviewed
    Format: text
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