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Full-Text Articles in Physics

Innovative Representations Of Light, Behaving As Both Particles And Waves, Among The Paintings Of Monet And Renoir, Charles Smith Nov 2014

Innovative Representations Of Light, Behaving As Both Particles And Waves, Among The Paintings Of Monet And Renoir, Charles Smith

Charles Kay Smith

Monet and Renoir, friends collaborating in open air about 1865, discovered that sunlight filtering through a canopy of tree leaves does not produce the splotches and dapples that studio artists conventionally represented at the time but circles of light. Sometimes the circles of light punctuating the shade are clear, separate and crisp, as though light is being propagated as particles, but if the pin-hole gaps between leaves are very close together, they will project compound or superimposed circles that look like the waves that Thomas Young saw in his double slit experiment in 1803-4. Newton’s Opticks published in 1704 had …


Raman Scattering Study Of Phase Biaxiality In A Thermotropic Bent-Core Nematic Liquid Crystal, Min Sang Park, Beom-Kin Yoon, Jung Ok Park, Veena Prasad, Satyendra Kumar, Mohan Srinivasarao Oct 2013

Raman Scattering Study Of Phase Biaxiality In A Thermotropic Bent-Core Nematic Liquid Crystal, Min Sang Park, Beom-Kin Yoon, Jung Ok Park, Veena Prasad, Satyendra Kumar, Mohan Srinivasarao

Satyendra Kumar

Polarized Raman spectroscopy was used to investigate the development of orientational order and the degree of phase biaxiality in a bent-core mesogenic system. The values of the uniaxial order parameters ⟨P200⟩ and ⟨P400⟩, and biaxial order parameters ⟨P220⟩, ⟨P420⟩, and ⟨P440⟩, and their evolution with temperature were determined. The temperature dependence of almost all order parameters reveals a second order transition from the uniaxial to biaxial nematic phase with ⟨P220⟩ increasing to ∼0.22 before a first order transition to the smectic-C phase, upon cooling.


One Order Parameter Tensor Mean Field Theory For Biaxial Liquid Crystals, Xiaoyu Zheng, Peter Palffy-Muhoray Oct 2013

One Order Parameter Tensor Mean Field Theory For Biaxial Liquid Crystals, Xiaoyu Zheng, Peter Palffy-Muhoray

Xiaoyu Zheng

In this paper, we present a simple one tensor mean field model of biaxial nematic liquid crystals. The salient feature of our approach is that material parameters appear explicitly in the order parameter tensor. We construct the free energy from a mean field potential based on anisotropic dispersion interactions, identify the order parameter tensor and its elements, and obtain self-consistent equations, which are then solved numerically. The results are illustrated in a 3D ternary phase diagram. The phase behavior can be simply related to molecular parameters. The results may be useful for designing molecules that show a thermotropic biaxial phase.


Coexistence Of Two Colloidal Crystals At The Nematic-Liquid-Crystal-Air Interface, A. B. Nych, V. M. Pergamenshchik, B. I. Lev, V. G. Nazarenko, I. Muševič, M. Škarabot, Oleg Lavrentovich Oct 2013

Coexistence Of Two Colloidal Crystals At The Nematic-Liquid-Crystal-Air Interface, A. B. Nych, V. M. Pergamenshchik, B. I. Lev, V. G. Nazarenko, I. Muševič, M. Škarabot, Oleg Lavrentovich

Oleg Lavrentovich

Glycerol droplets at a nematic-liquid-crystal–air interface form two different lattices—hexagonal and dense quasihexagonal—which are separated by the energy barrier and can coexist. Director distortions around each droplet form an elastic dipole. The first order transition between the two lattices is driven by a reduction of the dipole-dipole repulsion through reorientation of these dipoles. The elastic-capillary attraction is essential for the both lattices. The effect has a many-body origin.


Synthesis Of Al2tio5 And Its Effect On The Properties Of Chitosan-Nh4scn Polymer Electrolytes, Siti Rohana Majid, Hassan F., Woo H. J., Aziz N. A., Kufian M. Z. Dec 2012

Synthesis Of Al2tio5 And Its Effect On The Properties Of Chitosan-Nh4scn Polymer Electrolytes, Siti Rohana Majid, Hassan F., Woo H. J., Aziz N. A., Kufian M. Z.

Siti Rohana Majid

In this paper, Al2TiO5 ceramic material has been synthesised and used as filler in polymer electrolyte system to enhance the conductivity. The precursor sintered at 1,050 A degrees C and contained 0.08 mole of aluminium nitrate gives the best and complete formation of Al2TiO5. Composite polymer electrolytes of chitosan-NH4SCN containing different amount of home-made Al2TiO5 were prepared by solution casting. The addition of filler has enhanced the conductivity of polymer electrolyte. The sample 57 wt% chitosan-38 wt% NH4SCN-5 wt% Al2TiO5 exhibited the highest electrical conductivity of 2.10 x 10(-4) S cm(-1) at room temperature. The presence of the Al2TiO5 creates …


Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. A. Anchordoqui, G. Cooperman, V. Grinberg, T. P. Mccauley, T. Paul, S. Reucroft, J. D. Swain, G. Alverson Apr 2012

Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. A. Anchordoqui, G. Cooperman, V. Grinberg, T. P. Mccauley, T. Paul, S. Reucroft, J. D. Swain, G. Alverson

Thomas Paul

We present an evaluation of a simulated cosmic ray shower, based on GEANT4 and TOP-C, which tracks all the particles in the shower. TOP-C (Task Oriented Parallel C) provides a framework for parallel algorithm development which makes tractable the problem of following each particle. This method is compared with a simulation program which employs the Hillas thinning algorithm.


Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. A. Anchordoqui, G. Cooperman, V. Grinberg, T. P. Mccauley, T. Paul, S. Reucroft, J. D. Swain, G. Alverson Jan 2011

Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. A. Anchordoqui, G. Cooperman, V. Grinberg, T. P. Mccauley, T. Paul, S. Reucroft, J. D. Swain, G. Alverson

John Swain

We present an evaluation of a simulated cosmic ray shower, based on GEANT4 and TOP-C, which tracks all the particles in the shower. TOP-C (Task Oriented Parallel C) provides a framework for parallel algorithm development which makes tractable the problem of following each particle. This method is compared with a simulation program which employs the Hillas thinning algorithm.


Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. A. Anchordoqui, G. Cooperman, V. Grinberg, T. P. Mccauley, T. Paul, S. Reucroft, J. D. Swain, G. Alverson Jan 2011

Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. A. Anchordoqui, G. Cooperman, V. Grinberg, T. P. Mccauley, T. Paul, S. Reucroft, J. D. Swain, G. Alverson

George Alverson

We present an evaluation of a simulated cosmic ray shower, based on GEANT4 and TOP-C, which tracks all the particles in the shower. TOP-C (Task Oriented Parallel C) provides a framework for parallel algorithm development which makes tractable the problem of following each particle. This method is compared with a simulation program which employs the Hillas thinning algorithm.


Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. Anchordoqui, G. Cooperman, V. Grinberg, T. Mccauley, T. Paul, S. Reucroft, J. Swain, G. Alverson Dec 2010

Air Shower Simulation Using Geant4 And Commodity Parallel Computing, L. Anchordoqui, G. Cooperman, V. Grinberg, T. Mccauley, T. Paul, S. Reucroft, J. Swain, G. Alverson

Gene D. Cooperman

We present an evaluation of a simulated cosmic ray shower, based on GEANT4 and TOP-C, which tracks all the particles in the shower. TOP-C (Task Oriented Parallel C) provides a framework for parallel algorithm development which makes tractable the problem of following each particle. This method is compared with a simulation program which employs the Hillas thinning algorithm.


Shape-Persistent V-Shaped Mesogens-Formation Of Nematic Phases With Biaxial Order, Matthias Lehmann, Shin-Woong Kang, Christiane Köhn, Sönke Haseloh, Ute Kolb, Dieter Schollmeyer, Qingbing Wang, Satyendra Kumar Dec 2005

Shape-Persistent V-Shaped Mesogens-Formation Of Nematic Phases With Biaxial Order, Matthias Lehmann, Shin-Woong Kang, Christiane Köhn, Sönke Haseloh, Ute Kolb, Dieter Schollmeyer, Qingbing Wang, Satyendra Kumar

Satyendra Kumar

A homologous series of shape-persistent V-shaped molecules has been designed to form the biaxial nematic phase. Phenyleneethynylene moieties are attached to a bent fluorenone unit to create an apex angle of about 90°, which is determined from the single crystal structure. Two mesogens, one symmetric and another unsymmetric, have been synthesized by attaching a cyano group to one or both of the peripheral phenyl units, respectively. These groups introduce local dipoles essential for the formation of the nematic phases. The tendency to form a crystalline phase is reduced by laterally substituted hexyloxy chains which allow the nematic phase to be …