RESUMO
The precise observation of a solid-liquid interface by means of frequency modulation atomic force microscopy (FM-AFM) was performed, demonstrating its applicability to a study on lead acid batteries using an electrochemical test cell for in-liquid FM-AFM embedded with a specialized cantilever holder. The consistency and reproducibility of each surface profile observed via amplitude modulation AFM and FM-AFM were verified properly in a strong acidic electrolyte. In terms of FM-AFM, the ability to observe remarkable changes in the force mapping is the most beneficial, especially near the negative electrode surface. The localization of lignosulfonate (LS) added into the electrolyte as an expander could be visualized since this characteristic force mapping was captured when LS was added to electrolyte.
RESUMO
A two-dimensional high-speed, long-range tomography and profilometry based on a low-coherence optical interferometry has been developed. A liquid-crystal Fabry-Perot resonator is fabricated to be a low-coherence optical frequency comb generator for expanding the measurement depth of the tomography and profilometry. The line-shape interference fringes with the individual fringe orders are obtained by a CCD camera in real time. The relative optical length, corresponding to the sample depth information, can be derived from the positions of the interference fringes on the CCD camera and their corresponding fringe orders. The fringe orders can be rapidly calculated using the effectiveness of the changeable extraordinary refractive index of the liquid-crystal material of the resonator. The finesse of the liquid-crystal resonator is approximate 9, giving an expansion of the measurement range of up to 9-fold (â¼8 mm depth) with a resolution of profilometry and tomography of 3.7 µm and 11 µm, respectively.
RESUMO
In this study, we demonstrated the evaluation of the device parameters, such as the cell thickness d, pretilt angles at the top and bottom substrates θ0 and θd, and twist angle φt for the guest-host (GH)-type electrically controlled birefringence (ECB) and twisted nematic (TN) modes, using the renormalized transmission ellipsometry (RTE). In the proposed technique, the extended Cauchy equation and the extinction coefficients for the ordinary and extraordinary rays based on the three Gaussian functions were employed as a description of the dielectric function. As a result, the numerically calculated phase difference Δ and angle of amplitude ratio Ψ determined using the proposed technique provided good agreement with the measured Δ and Ψ by introducing the extinction coefficient to the RTE. Furthermore, the device parameters for the GH-ECB and the GH-TN cells were obtained. It was confirmed that the extinction coefficient should be taken into consideration in an analysis of GH liquid crystal displays.
RESUMO
Isotropic untreated indium-tin-oxide layers can cause memory alignment of nematic liquid crystals. We have demonstrated an experimental method to characterize this effect by using a micropatterned surface. We tried to imprint a high tilt on an indium-tin-oxide substrate surface. We also investigated microscopic switching behavior of a memory-induced nematic liquid crystal cell by means of a vertical field effect.
RESUMO
The liquid-crystal molecular order near the rubbed polymer surface is reexamined by the improved torque balance method. The surface azimuthal anchoring strength measured by the improved torque balance method is several times larger than that believed conventionally, considered to be significantly affected by the phase-transition behavior. Based on this result, it can be argued that the correlation between the rubbing strength and the surface azimuthal anchoring strength should be improved in consideration of the mechanism of surface order.
