• Journal of Information Display
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• 제13권4호
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• pp.145-149
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• 2012

Liquid crystals are useful for a wide range of applications due to their exceptional properties. Doping of liquid crystals with carbon nanotubes (CNTs), even at very low concentrations, produces a detectable effect on the liquid crystal (LC) properties that can be very attractive for various functions. In this study, an attempt was made to investigate the effect of CNTs on the electrical properties of a short-pitch and high-spontaneous-polarization ferro-electric LC mixture, FLC-6304, at different temperatures. The inclusion of the CNTs significantly reduced the polarization at temperatures well within the $SmC^*$ phase, but the effect was gradually reversed as the transition temperature was approached. The insertion of the CNTs also reduced the response time and the rotational viscosity of the FLC mixture, which is highly desirable in the LCD industry.

• Journal of the Korean Physical Society
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• 제73권11호
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• pp.1663-1674
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• 2018

We propose the Poynting vector analysis of the air mode in a top-emitting organic light-emitting diode (OLED) by combining the transfer matrix method and dipole source term. The spatial profiles of the time-averaged optical power flow of the air mode are calculated inside and outside the multilayer structure of the OLED with respect to the thickness of the semi-transparent top cathode and capping layer (CPL). We elucidate how the micro-cavity effect controlled by the thickness variation of the semi-transparent top cathode or CPL affects the internal optical power and absorption loss inside the OLED multilayer and the external optical power coupled into the air. When the calculated absorption loss and external power obtained by the proposed Poynting vector and currently-used point dipole models are compared, two calculation results are identical, which demonstrates the validity of the two models.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1143-1146
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• 2007

We carried out the human visual evaluation on PDPs and LCDs to clarify the viewer preference and the related physical and physiological factors. In the subjective evaluation, the impression test using the semantic differential method was carried out. In the objective evaluation, the eye motion tracking system was used. Our study showed that considering the real usage, the optimum display for viewers was that which showed more soft and smooth image without blurring.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.163-166
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• 2006

We found dramatic changes of the properties of LCs by dispersing ferroelectric nanoparticles. Specifically, ferroparticles greatly increase the nematic-isotropic transition temperature, birefringence and dielectric anisotropy of the LC. Ferroelectric nanoparticles/LCs colloids offer a simple and effective means to precisely control the physical properties of LC materials and optimize them for display applications.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1061-1066
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• 2005

Analytical solutions are obtained for the director reorientation dynamics of both VA and IPS modes by considering a possible effect of the molecular flow, providing a theoretical basis of the relations between the response characteristics of the display and the physical properties of the liquid crystal material used. The relevant properties of practical liquid crystal mixtures are quantitatively reviewed and the features of superior substances, used in formulating those mixtures, are presented.

• Journal of Information Display
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• 제10권2호
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• pp.76-79
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• 2009

In Joule-heating-induced crystallization, solid-to-solid or liquid-to-solid phase transformation could occur. It was found that novel physical phenomena that randomly nucleated liquid seeds, followed by rapid solidification in an amorphous matrix, during the Joule-heating-up period play an important role especially in liquid-to-solid transformation. Under some processing conditions, super-grains sized 6-8 ${\um}m$ were produced by the lateral growth from the initial seeds, without any artificially control.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.155-160
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• 2005

Computer simulations of a pdp discharges provide unique information necessary for their analysis, unavailable otherwise. Statistical instability of the ramp discharge and the role of exoemission, nature of striations during sustain discharge, physical mechanism responsible for the propagation of the cathode ionization wave, and line loading effects are just a few examples when simulations can be successfully used.

• 반도체디스플레이기술학회지
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• 제5권4호
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• pp.29-34
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• 2006

In order to design an OLED(Organic Luminescent Emitting Device) evaporation system, geometric simulation of film thickness distribution profile is required. For the OLED evaporation process, thin film thickness uniformity is of great practical importance. In this paper, a geometric modeling algorithm is introduced for process simulation of the OLED evaporating process. The physical fact of the evaporating process is modeled mathematically. Based on the developed method, the thickness of the thin-film layer can be successfully controlled.

• 한국전문물리치료학회지
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• 제28권2호
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• pp.117-122
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• 2021

Background: Flat-back posture refers to a posture in which the pelvis is tilted backward, the lumbar spine is bent, the upper thoracic spine is increasingly bent, and the lower thoracic spine is straight. Given that most of the day is spent sitting, we need to develop exercise programs and devices that are suitable for people who spend less time exercising than sitting. Objects: This study investigated the effects of resistance footrest exercise on spine posture angles in visual display terminal (VDT) workers with flat back. Methods: We measured the upper lumbar angle (ULA) and lower lumbar angle (LLA) using a flexible ruler for the ULA and LLA. Then, after 1 week of resistance footrest exercise designed to strengthen the lumbar spine musculature, we measured these angles again. We measured each angle three times and then compared measurements from before and after exercise. Results: There were no significant differences in the ULA following the strengthening exercise, but significant differences were observed in LLA. Conclusion: The resistance footrest exercise strengthened the muscles affecting the pelvic and lumbar lordotic angles, and increases in the LLA were changed. This suggests that the role of the lower lumbar spine in the lumbar lordotic curve is greater than that of the upper lumbar spine. In addition, considering the contemporary tendency to lead fairly sedentary lives, these results indicate that exercising while seated can be effective.

• Current Photovoltaic Research
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• 제2권1호
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• pp.14-17
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• 2014

In this paper, indium reduced materials for transparent conductive electrodes (TCE) were fabricated and their physical properties were evaluated. Two of materials, indium-zinc-tin oxide (IZTO) and aluminum (Al) were selected as TCE materials. In case of IZTO nanoparticles, composition ratios of In, Zn and Sn is 8:1:1 were synthesized. Size of the synthesized IZTO nanoparticles were less than 10 nm, and specific surface areas were about $90m^2/g$ indicating particle sizes are very fine. Also, the IZTO nanoparticles were well crystallized with (222) preferred orientation despite it was synthesized at the lowered temperature of $300^{\circ}C$. Composition ratios of In, Zn and Sn were very uniform in accordance with those as designed. Meanwhile, Al was deposited onto glass by sputtering in a vacuum chamber for mesh architecture. The Al was well deposited onto the glass, and no pore was observed from the Al surface. The sheet resistance of Al on glass was about $0.3{\Omega}/{\square}$ with small deviation of $0.025{\Omega}/{\square}$, and adhesion was good on the glass substrate since no pelt-off part of Al was observed by tape test. If the Al mesh is combined with ink coated layer which is consistent of IZTO nanoparticles, it is expected that the good and reliable metal mesh architecture for TCE will be formed.