Search results for "Perpendicular"
showing 10 items of 168 documents
Effect of uniaxial deformation on the optical scattering losses of a semicrystalline fluorocopolymer.
1997
Both small- and wide-angle light scattering as well as transmission measurements have been used to investigate the optical scattering losses of a vinylidene difluoride–tetrafluoroethylene–hexafluoropropylene copolymer crystallized from the melt. The main origin of the scattering loss is the wide-angle light scattering from the spherulitic superstructure. Uniaxial deformation transforms this structure into a fiber morphology. The attenuation of fibers has been measured for light propagating both parallel and perpendicular to the orientation axis. For both directions, the attenuation decreases with increasing draw ratio. Annealing of the fibers while keeping their ends fixed is an effective m…
2,4,6-Tris(1-oxo-2-pyridylsulfanylmethyl)mesitylene methanol solvate
2008
In the title compound, C(27)H(27)N(3)O(3)S(3)·CH(4)O, the dihedral angles formed by the mesitylene ring with the three oxopyridyl rings are 89.6 (1), 75.5 (1) and 80.69 (1)°, indicating that all three are nearly perpendicular to the mesitylene ring. Intra-molecular C-H⋯S hydrogen bonds generate S(6) ring motifs. The crystal structure is stabilized by intra-molecular C-H⋯S and inter-molecular C-H⋯O hydrogen bonds and weak C-H⋯π inter-actions.
Phase separation of an asymmetric binary fluid mixture confined in a nanoscopic slit pore: Molecular-dynamics simulations
2008
As a generic model system of an asymmetric binary fluid mixture, hexadecane dissolved in carbon dioxide is considered, using a coarse-grained bead-spring model for the short polymer, and a simple spherical particle with Lennard-Jones interactions for the carbon dioxide molecules. In previous work, it has been shown that this model reproduces the real phase diagram reasonable well, and also the initial stages of spinodal decomposition in the bulk following a sudden expansion of the system could be studied. Using the parallelized simulation package ESPResSo on a multiprocessor supercomputer, phase separation of thin fluid films confined between parallel walls that are repulsive for both types…
Short- and long-range order in La1−xSrxCoO3 and La1−xBaxCoO3
2008
Abstract The short- and long-range order correlations of the crystal structure in the distorted perovskites La 1− x Sr x CoO 3 and La 1− x Ba x CoO 3 (0.0⩽ x ⩽0.5) have been studied by the neutron powder diffraction (NPD) and the Co K-edge X-ray absorption spectroscopy (XAS) measurements. The results of XAS and NPD indicate a local distortion around the Co 3+ ions in LaCoO 3 at room temperature. The substitution of the La 3+ ions by the Sr 2+ (Ba 2+ ) ions leads to a gradual increase of the Co–O–Co angle and is accompanied by an increase of the mean square relative displacement (MSRD) of the Co–O bond. These results correlate with an increase of the oxygen amplitude vibration in the directi…
Système de prise d'images haute résolution pour l'analyse de projection de particules : application à l'épandage centrifuge d'engrais
2002
This paper describes the design of a high resolution low cost imaging system for the analysis of high speed particle projection. This system, based on a camera and a set of flashes, is used to characterize the centrifugal spreading of fertilizer particles ejected at speeds of environ 30 m s. Multiexposure images collected with the camera installed perpendicular to the output flow of granules are analysed to estimate the trajectories of the fertilizer granules. Very good results are obtained with the Markov random fields method, in comparison with others.
Refractive index of GaTe under high pressure
2000
In this paper we describe two experiments, in the near- and mid-infrared, designed to investigate the evolution under pressure of the GaTe refractive index for polarization parallel and perpendicular to the crystallographic c-axis (in the layer plane). The refractive index dispersion for both light polarizations has been determined up to 5.5 GPa. It is found that the refractive index increases faster in the direction perpendicular to the c-axis than along the c-axis. To find out the origin of such a difference we used a Phillips-Van Vechten model and arrived at the conclusion that it is due to the different pressure behaviour of the Penn gap for each polarization.
Detection and orientation evaluation for three-dimensional objects
2003
This paper presents a novel method for detection and orientation evaluation for three-dimensional (3-D) objects based on range images. It is based on the calculation of the phase Fourier transform of the 3-D object range image. The method permits the estimation of the angular position of the object. It works with rotations around an axis perpendicular to the line of sight, although it exhibits a certain nodding tolerance. Simulated results demonstrate the ability of the new introduced method.
Surface anchoring on liquid crystalline polymer brushes
2002
We present a Monte Carlo study of the surface anchoring of a nematic fluid on swollen layers of grafted liquid crystalline chain molecules. The liquid crystalline particles are modeled by soft repulsive ellipsoids, and the chains are made of the same particles. An appropriately modified version of the configurational bias Monte Carlo algorithm is introduced, which removes and redistributes chain bonds rather than whole monomers. With this algorithm, a wide range of grafting densities could be studied. The substrate is chosen such that it favors a planar orientation (parallel to the surface). Depending on the grafting density, we find three anchoring regimes: planar, tilted, and perpendicula…
Compression-induced anti-nematic order in glassy and semicrystalline polymers
2020
We provide new insights into the molecular origin of the asymmetry between uniaxial tensile and compressive deformation of glassy and semicrystalline polymers using molecular dynamics simulations. The difference between the two responses strongly depends on the chain length and is the largest at intermediate chain lengths. Irrespective of chain length, the intra- and interchain organization of polymers under extension and compression are remarkably distinct. The chains align along the tensile axis leading to a global nematic order of the bonds and end-to-end vectors, whereas compression reorganizes polymers to lie in planes perpendicular to the compressive axis resulting in the emergence of…
Unmixing of Polymer Blends Confined in Ultrathin Films: Crossover between Two-Dimensional and Three-Dimensional Behavior
2006
The interplay between chain conformations and phase separation in binary symmetric polymer mixtures confined into thin films by "neutral" hard walls (i.e., walls that do not preferentially attract or repel one of the two components of the mixture) is studied by Monte Carlo simulations. Using the bond fluctuation model on a simple cubic lattice in the semi grand canonical ensemble, we locate the critical temperature of demixing via finite size scaling methods for a wide range of chain lengths (16/= N/= 256 effective monomers per chain) and film thicknesses (2/= D/= 19 lattice spacings). Simultaneously, we investigate the geometrical structure of the chains, showing that despite using melt de…