• Journal of the Optical Society of Korea
• /
• 제17권5호
• /
• pp.428-432
• /
• 2013

This research presents a flexible reflective thermochromic display (TCD) comprised of thermochromic pigments and a patterned indium tin oxide (ITO) film coated on a polyethylene naphthalate (PEN) substrate, and the display's thermo-optical characteristics. The display showed maximum red, green, and blue reflectances of 30%, 38%, and 29%, respectively. Furthermore, the display exhibited a continuous grey color when the temperature was changed continuously. As a flexible display, the display showed reliable thermo-optical performance without image damage even when highly bent. We expect the proposed TCD will be used in outdoor information display applications where low cost is a key factor.

• 영어어문교육
• /
• 제15권2호
• /
• pp.1-25
• /
• 2009

The purpose of this study is to explore the potential of peer coaching for EFL teachers' professional development. For this study, 12 college teachers in Korea participated in a 10-week program. They were 7 males and 5 females, ranging in age from 24 to 37 years. Data were collected through semi-structured interviews. Reflective analysis was used to analyze individual interview data. From the findings, two significant categories of peer coaching were identified: positive and negative responses to peer coaching experience. However, the overriding themes that emerged from the data were the benefits of peer coaching. The participants were almost unanimous in their acknowledgement of the advantages of peer coaching, such as reflective support through other's eyes, improved working environments, greater teaching strategies, higher professional self-esteem, and awareness of self-directed learning. Negative responses also appeared, mostly in regard to the working principles of implementation; the major issues of difficulties were time management, complexities of implementation procedure, stress and personal vulnerability, and relative lack of reflection and feedback skills. Demonstrating the participants' experiences towards the peer coaching program, this study provides EFL teachers with useful insights into peer coaching as an effective tool of their professional development.

• 한국수학교육학회지시리즈A:수학교육
• /
• 제42권3호
• /
• pp.303-325
• /
• 2003

This study sought to provide an explanation of university students' concept understanding on the infinity and infinite process and utilized a psychological constructivist perspective to examine the differences in transitions that students make from static concept of limit to actualized infinity stage in context of problems. Open-ended questions were used to gather data that were used to develop an explanation concerning student understanding. 47 university students answered individually and were asked to solve 16 tasks developed by Petty(1996). Microgenetic method with two cases from the expert-novice perspective were used to develop and substantiate an explanation regarding students' transitions from static concept of limit to actualized infinity stage. The protocols were analyzed to document student conceptions. Cifarelli(1988)'s levels of reflective abstraction and Robert(1982) and Sierpinska(1985)'s three-stage concept development model of infinity and infinite process provided a framework for this explanation. Students who completed a transition to actualized infinity operated higher levels of reflective abstraction than students who was unable to complete such a transition. Developing this ability was found to be critical in achieving about understanding the concept of infinity and infinite process.

• 한국수학교육학회지시리즈D:수학교육연구
• /
• 제6권2호
• /
• pp.123-133
• /
• 2002

The authors examined a college mathematics professor's change process in teaching practice by analyzing the teacher's reflective journal. Her change engaged cooperative learning method in a college Algebra course and was geared toward the reform-oriented methods. The change processes were revealed as a bumpy road that was full of struggles and challenges to both the teacher and students. The analysis also showed that a reflective journey needed a proper means and support system from a teacher's environment such as institution. This research clearly showed that brining a genuine change in teaching practice toward a broad educational goal was a combined effort among the participants of education.

• Journal of Information Display
• /
• 제4권2호
• /
• pp.25-28
• /
• 2003

We propose a new optical configuration of a hybrid-aligned nematic liquid crystal cell for reflective displays, which consist of a biaxial film for obtaining wide viewing angle and a half-wave film for achieving high contrast. As a result, we can achieve wide viewing angle of (80( for the horizontal direction and (50( for the vertical direction and uniform reflection spectrum.

• 대한전기학회논문지:시스템및제어부문D
• /
• 제54권6호
• /
• pp.403-408
• /
• 2005

As the increasing integrity of VLSI, the BIST(Built-In Self Test) is used as an effective method to test chips. Generally the pseudo-random test pattern generation is used for BIST. But it requires too many test patterns when there exist random This paper proposes and presents a new efficient network architecture for Reflective Memory System (RMS). A time to copy shared-data among nodes effects critically on the entire performance of the RMS. In this paper, the recent researches about the RMS are investigated and compared. The device named Topology Conversion Switch(TCS) is introduced to realize the proposed network architecture. One of the RMS based industrial control networks, Ethernet based Real-time Control Network (ERCnet), is adopted to evaluate the performance of the proposed network architecture for RMS.

• KIEE International Transactions on Electrophysics and Applications
• /
• 제11C권3호
• /
• pp.91-95
• /
• 2001

Reflective holographic polymer dispersed liquid crystal(HPDLC) device has a multilayer structure consisting of alternate layers of polymer and liquid crystal droplets. Periodic modulation of a refractive index reflects light of a specific wavelength in accordance with Braggs law. Samples cured isotropically were illuminated with an Argon-ion lase at 514nm. We optimized the reflcetion efficiency of HPDLC as a function of monomer functionality, LC composition and irradiation intensity. The properties of the HPDLC films were observed by UV-visible spectroscopy. We found that the maximum reflection efficiency depends on the monomer functionality, LC composition, and laser intensity. We expect these films could be used in full-color reflective display by stacking them to obtain a mixture of colors.

• Journal of information and communication convergence engineering
• /
• 제10권3호
• /
• pp.295-299
• /
• 2012

Defect generation during organic bottom anti-reflective coating (BARC) in the photo lithography process is closely related to humidity control in the BARC coating unit. Defects are related to the water component due to the humidity and act as a blocking material for the etching process, resulting in an extreme pattern bridging in the subsequent BARC etching process of the poly etch step. In this paper, the lower limit for the humidity that should be stringently controlled for to prevent defect generation during BARC coating is proposed. Various images of defects are inspected using various inspection tools utilizing optical and electron beams. The mechanism for defect generation only in the specific BARC coating step is analyzed and explained. The BARC defect-induced gate pattern bridging mechanism in the lithography process is also well explained in this paper.

• 한국표면공학회지
• /
• 제43권2호
• /
• pp.97-104
• /
• 2010

In this paper, we conducted MATLAB simulation using the reflectance formula and the Planck's black body radiation principle, for the purpose of identifying the opimum material and thickness of anti-reflective coating from double layered structures. We found that the optimum condition was obtained when refractive index of upper layer is 1.44 and that of lower layer is 2.29. As materials close to these refractive indices, $MgF_2$ as the upper layer and $HfO_2$, ZnS, $TiO_2$ as the lower layer were suggested. The best result in an average reflectance of 2.759% was obtained from a double layered structure of $MgF_2$ 94 nm/ZnS 55 nm.

• Transactions on Electrical and Electronic Materials
• /
• 제17권4호
• /
• pp.212-216
• /
• 2016

A reflective electronic display that uses negatively and positively charged particles has excellent bistability, a welldefined threshold voltage, and an extremely fast response time in comparison with other reflective displays. This type of display shows images through the movement of charged particles whose motion depends on the value of q/m (charge per mass for a particle). However, the ratio q/m can easily be changed by the forces acting on the charged particles in a cell of the panel and by friction that occurs after mixing oppositely charged particles and in the particle-insertion process. In this study, we propose a method to determine the appropriate range of q/m by using the reflectivity and response time of charged particles to modify q/m. In this manner, the electrical and optical properties of reflective displays are improved.