• Bulletin of the Korean Chemical Society
• /
• v.23 no.1
• /
• pp.98-102
• /
• 2002

The structure of a single crystal, grown by a slow cooling a melt of $Ca_{1.29}Bi_{0.14}VO_4$ composition, was analyzed. The crystals belong to the rhombohedral space group R3c and the dimensions of the unit cells are a = 10.848(1)${\AA}$, c = 38.048(6)${\AA}$, V = 3877.6(8)${\AA}^3$ for the pale yellow crystal, and a = 10.857(1), c = 38.063(6)${\AA}$, V = 3885.6(8)${\AA}^3$ for the yellow crystal, respectively. Unit cell dimensions of the crystal were larger than those of the host crystal, $Ca_3(VO_4)_2$, owing to the Bi that replaced Ca in the unit cell. Ca in the unit cell formed six, eight and nine coordinated polyhedra with O atoms and Bi replacing Ca entered the eight or nine coordinated Ca sites with different crystallographic environments in the unit cell. All the V in the unit cell formed four coordinated tetrahedra with O atoms, however V-O bond lengths in the tetrahedra were different from one another.

• Proceedings of the IEEK Conference
• /
• 2004.06b
• /
• pp.383-386
• /
• 2004

The one of important requisites for fabricating molecular electronic device is the single crystal direction of bottom substrate nowadays. [1,2]. We obtain the optimum SAM result when the Au crystal is <111> structure for Self-Assembled molecular. To get the <111> crystal Au, we generally repeat heating and cooling course after evaporating Au [3]. However, we can fabricate <111> crystal Av thin film except post treatment because we simultaneously evaporate and anneal using Effusion Cell. In this paper, we study on thin film growth of <111> crystal Au as bottom electrode which is essential for Self-Assembled molecular by Effusion Cell and analyze crystal structure, thickness, surface conductivity and so on as each process condition.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2003.07a
• /
• pp.1096-1100
• /
• 2003

A fast Q-tensor method, which can model the defect dynamics in a liquid crystal director field is presented. The method is used to model the defect dynamics occurring during the "warm-up" of a ${\pi}-cell$ device.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.13 no.6
• /
• pp.261-266
• /
• 2003

The presence of ultrasonic wave in the caustic etching process enhances the etching rate and results in finer and more homogeneous textured structure of the crystalline silicon surface. The silicon solar cell textured in the caustic solution at $60^{\circ}C$ with ultrasonic wave gives higher cell performance than the cell textured at $70^{\circ}C$ without ultrasonic wave. This result indicates a strong possibility of lowering the production cost of the silicon solar cell through saving the thermal budget or expensive chemical normally employed in the texturisation of the crystalline silicon.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.567-570
• /
• 2007

Cell gap dependence on anisotropic phase separation was studied. The results showed that the morphology of phase separation depended on cell gap and material parameters. With numerical simulation and experiments, the optimal range of cell gap in the formation of polymer layer and liquid crystal was suggested for given material parameters.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.4
• /
• pp.10-18
• /
• 2002

This paper reports a methodology for calculating distribution of the director in an In-plane switching liquid crystal cell by a numerical technique. To calculate distribution of the director, we developed a three dimensional finite element method (FEM) and calculated the distribution of electric potential and electric field in the liquid crystal cell. We have considered the free-energy density composed of electric potential and strain energy in the bulk of liquid crystal cell and calculated the switching property of liquid crystal cell by the Ericksen-Leslie equation and the Laplace equation We generated 1,859 nodes and 8,640 elements for IPS mode cell with 24${\mu}{\textrm}{m}$$\times$12${\mu}{\textrm}{m}$$\times$4.5${\mu}{\textrm}{m}$ and performed transient analysis until 16ms. As a result, horizontal electric field occurred at cell region except liquid crystal region above electrodes and the disclination occured on electrodes.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.681-682
• /
• 2009

We fabricated a stressed liquid crystal cell by mixing liquid crystal with a photo-polymer. By carefully choosing the mixing ratio between liquid crystal and the polymer, and by suitable mechanical shearing of the substrates, we demonstrated feasible electro optical properties for displays.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.855-858
• /
• 2008

Transient current (TC) on bulk-state liquid crystal mixtures was measured. We found that TC is very sensitive to impurities and the features of TC curves depend on the type of contamination, from which the quality of materials can be definitely evaluated and the type of impurities can also be revealed.

• Korean Journal of Optics and Photonics
• /
• v.5 no.3
• /
• pp.411-417
• /
• 1994

The electro-optic polarization transmission characteristics of a liquid crystal (LC) cell is represented by a rotational transformation on the Poincare sphere, and its characteristic parameters, the angle and the axis of the rotation, are experimentally determined with respect to the voltage applied to the LC cell. From the experimental data obtained, we determine driving voltage for the LC cell to give the rotation angle near $180^{\circ}$ of the rotation for the change of the state of the LC cell from non-select to select state, which is a necessary condition for the realization of maximally bright images. The directions of the transmission axes of the polarizer and the analyzer which form a liquid crystal display panel together with the LC cell, are determined from the general characteristics of the rotaional transformation of the LC cell. cell.

• Korean Journal of Optics and Photonics
• /
• v.12 no.6
• /
• pp.468-471
• /
• 2001

A novel method to measure the cell gap of a single-polarizer reflective twisted nematic liquid crystal (TN LC) cell by using a rotating polarizer technique is proposed. By rotating an LC cell, we can measure the cell gap of an LC cell as well as the wavelength dependence of retardation under the condition that the twist angle is known.