• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.1
• /
• pp.160-170
• /
• 2002

Many of aged and damaged concrete structure have been revitalized with composite reinforcement. Flexural behaviors of composite-patched concrete specimens are characterized by high-sensitivity moire interferometry. The three-mirror, four-beam interferometry system and a compact loading system are used for obtaining singe patterns representing whole-field contour maps of in-plane displacements. It is seen from the calibration test for the loading system that the measured bending displacement is in excellent agreement with the displacement calculated by the beam theory. The crack opening displacement as well as the bending and the horizontal displacement fur the notched and unnotched specimen are investigated. The results also show that the notched specimen reinforced by a composite sheet has sufficient stiffness and strength compared to the original concrete specimen.

• Laser Solutions
• /
• v.12 no.2
• /
• pp.26-30
• /
• 2009

Scanning Electron Microscopy (SEM) includes high voltage generator, electron gun, column, secondary electron detector, scan coil system and image grabber. Column includes electron lenses (condenser lens and objective lens). Condenser lens generates fringe field, makes focal length and control spot size. Focal length represents property of lens. Objective lens control focus. Most of the electrons emitted from the filament, are captured by the anode. The portion of the electron current that leaves the gun through the hole in the anode is called the beam current. Electron beam probe is called the focused beam on the specimen. Because of the lens and aperture, the probe current becomes smaller than the beam current. It generate various signals(backscattered electron, secondary electron) in an interaction with the specimen atoms. In this paper, we describe the result of research to develop the core elements for low-resolution SEM.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.439-442
• /
• 2005

In this paper, we propose a cell structure to improve transmittance and aperture ratio with FFS(Fringe Field Switching) mode. As an exemplary cell, we selected conventional FFS cell with dual domain. Optical transmittance and aperture ratio were calculated with 3DFEM numerical solver, TechWiz LCD. The simulation results revealed that transmission increases by more than 10% while aperture ratio increases by more than 4% when compared to conventional FFS mode.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2005.07a
• /
• pp.357-360
• /
• 2005

A novel wide viewing angle flexible liquid crystal display will be demonstrated. The crossed matrix-type micro-cell structure was adopted in this design. The LC domains were divided into four different tilted directions by the combination effect of pixel fringe field and crossed matrix type micro-cell. It can create four domains without rubbing process and form the cell gap without spacer. For flexible color fabrication, a novel inkjet printing technology is adopted. This cost effective wide viewing angle color flexible LCD technology can be a good solution for high performance flexible LCD.

• Proceedings of the Korean Society for Environmental Edudation Conference
• /
• 2002.12a
• /
• pp.79-85
• /
• 2002

Inquiry activity contents presented at a chapter on natural environment and our lives in 6 science textbooks of the middle school were analyzed based on kinds of the inquiry Loaming classified by textbook. The number of inquiry activity subjects showed severe variation as mean value was 8.3${\times}$3.7 ranged from 4 to 15. Moreover, textbooks had little common point among each other as the percentage of subjects appeared together in the textbooks more than 3 kinds, 50% of total ones investigated, was just 26.3%. Data interpretation occupied significant position in the inquiry activity as 42% of total activity contents, whereas observation and experiment (or survey) did slight part of the activity as 10% and 16%, respectively even though they are main factors of science education. A model for field education based on the reasonable common subjects was prepared in the Gildong ecological park located In the eastern fringe of Seoul as a plan in order to solve the problems.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.43 no.4
• /
• pp.620-626
• /
• 1994

As the electrostrictive actuator for optic control, PZN-BT-PT ceramics were investigated for the influences of sintering conditions on the structural, electrostrictive properties and the optical properties of Fabry-perot Interferometer using eletrostrictive ceramics. The specimen SS15T, sintered 1hr at 1150$^{\circ}C$, is sutible for eletrostrictive actuator because its piezoelectric constants(dS131T) and strain(XS131T) at dc 10kV/cm had the higest value of 175${\times}$10S0-12TC/N, -255${\times}$10S0-6TΔl/l respectively. As the dc electric field increased, the interference effect of Fabry-Perot Interferometer was increased. The most intense interference fringe and the maximum power of 160${\mu}$W were observed at dc 6kV/cm. Thus it was considered that specimen SS15T could be used as the electrostrictive actuator for optic control.

• Korean Journal of Optics and Photonics
• /
• v.24 no.6
• /
• pp.324-330
• /
• 2013

Phase-measuring deflectometry is a full-field gradient measuring technique that lends itself very well to testing specular optical surfaces. We have measured deformation of a large specular surface by deflectometry. In this work, we have used a Fourier-transform method to get the phase from a measured deformed fringe pattern, and we have used least squares method to obtain the height information of the specular surface from the calculated slope. Experimentally, we have confirmed that deflectometry can be used for deformation measurement of a specular surface like that of a wafer.

• Proceedings of the KIEE Conference
• /
• 1987.07a
• /
• pp.90-93
• /
• 1987

Phase conjugate wavefront generation via real-time holography in degenerate four-wave mixing experiments in photo-refractive crystal $Bi_{12}$ Si $O_{20}$ is presented. Depending on the respective values of applied field $E_o$ and fringe spacing, drift or diffusion of the photecarriers dominates the space-charge buildup and affects the Phasa- Conjugate Wavefront intensity. The experimental results for wavefront reflectivity as a function of the intensity ratio of the writing beams agree with the theoretical predictions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.06a
• /
• pp.435-436
• /
• 2007

In general, Single gap transflective FFS display has an in-cell retarder (ICR) between reflective electrode and liquid crystal (LC) layer. Therefore, Operating voltage is highly increased due to this thick dielectric material. But, we also knew the phenomenon that the increasing rate of Vop is different whether the 1st common electrode was composed of plate type or slit type. In this paper, the common electrode in transmissive part was composed of slit type which had less steepness effect of the V op and in reflective part was composed of plate type. The rubbing angle of reflective part can be adjusted properly to match the voltage dependent transmittance and reflectance.

• Journal of the Optical Society of Korea
• /
• v.19 no.3
• /
• pp.260-264
• /
• 2015

We propose a negative liquid crystal (n-LC) cell with parallel patterned electrodes for high transmittance and fast response. The proposed cell has higher transmittance and shorter response time than a conventional fringe-field switching cell using n-LCs, because the proposed cell does not have transmittance dips and does have a thinner LC layer.