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Incommensurate Smectic Order at the Free Surface in the Nematic Phase of \(4-N-Heptylphenyl-4'-(4"-Nitrobenzoyloxy)Benzoate (DB7NO_2)\)
(American Physical Society, 1987)
We report x-ray reflectivity measurements on the free surface of \(4-n-heptylphenyl-4'-(4"-nitrobenzoyloxy)benzoate (DB7NO_2)\) at the nematic to smectic-A phase transition, \(T_{NA}=99.9^{\circ}C\). The free surface in ...
Ab Initio Theory of Polar Semiconductor surfaces. II. (2x2) Reconstructions and Related Phase Transitions of GaAs(1¯1¯1¯)
(American Physical Society, 1987)
The (2×2) reconstructions of GaAs(1¯ 1¯ 1¯) are studied with use of a theoretical approach based on the calculation of the total energy in the context of density-functional theory and the pseudopotential approximation. New ...
Transition-State Model for Entropy-Limited Freezing
(Materials Research Society, 1987)
A brief review is given of transition-state theory, both for the case of unimolecular reactions in the gas phase, and for reactions in condensed phases. An argument is made that, within the context of this theory, heterogeneous ...
Synchrotron X-Ray Observation of Surface Smectic-I Hexatic Layers on Smectic-C Liquid-Crystal Films
(American Physical Society, 1987)
Synchrotron x-ray diffraction methods employing a position-sensitive detector were used to study smectic-C (SmC) and smectic-I (SmI) phases in thin (2–6 molecular layers) liquid-crystal films of 4-(n-heptyloxy)benzyliden ...
Liquid and Liquid Crystal Surfaces
(National Academy of Sciences, 1987)
X-Ray and Optical Studies of the Thickness Dependence of the Phase Diagram of Liquid-Crystal Films
(American Physical Society, 1987)
A comprehensive study of the thickness dependence of the phase diagram of freely suspended films of the liquid crystal 4-n-heptyloxybenzylidene-4-n-heptylaniline (7O.7) between \(50 and 69^{\circ}C\) is reported. In thick ...
Modulated Crystalline-B Phases in Liquid Crystals
(American Physical Society, 1987)
Detailed x-ray scattering studies of the modulated phases of 4-n-heptyloxybenzylidene-4-n-heptylaniline (7O.7) are reported. In addition to the previously identified one-dimensional modulation that appears at the transition ...
Smectic Layering at the Free Surface of Liquid Crystals in the Nematic Phase: X-Ray Reflectivity
(American Physical Society, 1987)
Smectic layering at the surface and smectic fluctuations in the bulk can be studied simultaneously by x-ray specular reflectivity and scattering measurements. There is a peak in the angular dependence of the specular ...
Atmospheric distribution of 85 Kr simulated with a general circulation model
(Wiley-Blackwell, 1987)
A three-dimensional chemical tracer model for the troposphere is used to simulate the global distribution of 85Kr, a long-lived radioisotope released at northern mid-latitudes by nuclear industry. Simulated distributions ...
An algorithm for generating quantifier scopings
(Association for Computing Machinery, 1987)
The syntactic structure of a sentence often manifests quite clearly the predicate-argument structure and relations of grammatical subordination. But scope dependencies are not so transparent. As a result, many systems for ...