排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
Dynamic light scattering spectroscopy has been used to determine the temperature dependence of the anchoring strength of the nematic liquid crystal 8OCB on DMOAP‐silanated glass surfaces inducing homeotropic alignment. Wedge‐type glass cells with known thickness profile starting from 150 nm to several microns have been used in the experiments. The relaxation rates of the nematic fluctuations with the wave vector perpendicular to the confining surfaces have been measured as a function of the cell thickness. Fitting of the thickness dependence of the relaxation rate allows for straightforward determination of the surface extrapolation length and therefore also the strength of the surface anchoring, which is 1×10?4 J m?2. The overall experimental accuracy of the experiments is discussed. 相似文献
2.
3.
We have measured the temperature dependence of the helical period in the ferroelectric, ferrielectric and antiferroelectric phases of (R)-MHPOBC and (R)-10OTBBB1M7. A combination of polarizing microscopy, measurements of optical rotation and the frequency dispersion of the electro-optic linear response has been used to determine both the magnitude and sense of the helical period. 相似文献
4.
We have measured the temperature dependence of the helical period in the ferroelectric, ferrielectric and antiferroelectric phases of ( R )-MHPOBC and ( R )-10OTBBB1M7. A combination of polarizing microscopy, measurements of optical rotation and the frequency dispersion of the electro-optic linear response has been used to determine both the magnitude and sense of the helical period. 相似文献
5.
Lev B Nych A Ognysta U Chernyshuk SB Nazarenko V Skarabot M Poberaj I Babic D Osterman N Musevic I 《The European physical journal. E, Soft matter》2006,20(2):215-219
The interaction between a colloidal particle and a focused laser beam in a nematic liquid crystal reveals an unusual anisotropic
Coulomb-like character. Experiments demonstrate two opposite directions in which the particle is attracted to and repelled
from the nematic region deformed by the light-induced director reorientation. In this work we present analytical analysis
of such behavior and derive the energy of interaction between colloidal particle and deformed director field. The analytical
solution is in good agreement with recent results obtained by computer simulation. 相似文献
6.
In a thin planar nematic cell, the application of an AC electric field induces a macroscopic transport of micrometer-sized
colloidal particles along the nematic director. We have analyzed the dependence of particle velocities on the electric-field
amplitude and frequency and found that it decreases exponentially with increasing frequency. Using specially designed electrodes
we have observed that colloidal particles could be pumped and accelerated across the field-no-field interface, and measured
the structural force and the corresponding potential, which is of the order of 10000 kBT for 4μm particles. We demonstrate that spatially periodic close-packed crystalline colloidal structures can be obtained,
which are thermodinamically metastable for many days after turning off the electric field and slowly decay into linear chains.
Above the nematic-isotropic phase transition, such crystalline structures are non-stable and decay in few minutes. 相似文献
7.
Summary LetR be a prime ring andd be a nonzero derivation ofR. If an additive mappingf ofR satisfiesd(x)f(x) = 0 for allx R, thenf vanishes on some nonzero left ideal ofR and on some nonzero right ideal ofR. 相似文献
8.
Gomilšek M Seč D Skarabot M Ravnik M Zumer S Muševič I 《The European physical journal. E, Soft matter》2010,33(4):291-296
Laser tweezers have been used to drive the oscillations of a chain of entangled colloidal particles in the nematic liquid
crystal 5CB. The amplitude and phase of light-driven oscillations have been determined for the motion of individual colloidal
particles. The collective motion of 4.8μm silica particles is highly damped for a driving frequency above 0.5Hz. The results
were compared to an effective bead-spring model, where the motion of elastically coupled particles is hindered by viscous
damping and hydrodynamic coupling. Qualitative agreement between theory and experiment was obtained. 相似文献
9.
Dynamic light scattering spectroscopy has been used to determine the temperature dependence of the anchoring strength of the nematic liquid crystal 8OCB on DMOAP-silanated glass surfaces inducing homeotropic alignment. Wedge-type glass cells with known thickness profile starting from 150 nm to several microns have been used in the experiments. The relaxation rates of the nematic fluctuations with the wave vector perpendicular to the confining surfaces have been measured as a function of the cell thickness. Fitting of the thickness dependence of the relaxation rate allows for straightforward determination of the surface extrapolation length and therefore also the strength of the surface anchoring, which is 1×10-4 J m-2. The overall experimental accuracy of the experiments is discussed. 相似文献
10.
M. Humar M. Škarabot M. Ravnik S. Žumer I. Poberaj D. Babič I. Muševič 《The European physical journal. E, Soft matter》2008,27(1):73-79
We show that diffraction of visible light from 2D dipolar nematic colloidal crystals can be tuned electrically. When the external
electric field of ∼ 1V/μm is applied in a direction perpendicular to the plane of the 2D colloidal crystal, the induced strain
is highly anisotropic, and the inter-colloidal spacing changes by as much as 20% along one direction and ∼ 2% along the perpendicular
one. Although the speed of response is in the range of several seconds, this novel mechanism could provide interesting photonic
applications. 相似文献