• Journal of the Semiconductor & Display Technology
• /
• v.9 no.4
• /
• pp.13-18
• /
• 2010

Extreme ultraviolet (EUV) lithography using 13.5 nm wavelengths is expected to be adopted as a mass production technology for 32 nm half pitch and below. One of the new issues introduced by EUV lithography is the shadowing effect. Mask shadowing is a unique phenomenon caused by using mirror-based mask with an oblique incident angle of light. This results in a horizontal-vertical (H-V) biasing effect and ellipticity in the contact hole pattern. To minimize the shadowing effect, a refilled mask is an available option. The concept of refilled mask structure can be implemented by partial etching into the multilayer and then refilling the trench with an absorber material. The simulations were carried out to confirm the possibility of application of refilled mask in 32 nm line-and-space pattern under the condition of preproduction tool. The effect of sidewall angle in refilled mask is evaluated on image contrast and critical dimension (CD) on the wafer. We also simulated the effect of refilled absorber thickness on aerial image, H-V CD bias, and overlapping process window. Finally, we concluded that the refilled absorber thickness for minimizing shadowing effect should be thinner than etched depth.

• Korean Journal of Optics and Photonics
• /
• v.17 no.2
• /
• pp.198-202
• /
• 2006

Resonator stability condition, $M^2$ beam quality factor, and laser output power are analyzed for two types of two-rod Nd:YAC lasers with rod-end curvatures. Two laser rods with rod-end curvatures are positioned closely to each other or placed separately near each resonator mirror. Experimentally, the output powers and $M^2$ beam quality factors of those lasers are measured with and without thermal birefringence compensation, and compared to numerical analyses.

• Journal of the Korean Solar Energy Society
• /
• v.29 no.1
• /
• pp.50-57
• /
• 2009

Heliostat in the tower type solar thermal power plant is a mirror system tracking the sun's movement to collect the solar energy and it is the most important subsystem determining the efficiency of solar thermal power plant. Thus a good performance of it, which is mostly the accurate sun tracking performance under the various hazardous operating condition, is required. Heliostat control system is a system to manage the heliostat sun tracking movement and other operations. It also communicates with the master controller through the heliostat filed control system to receive and send the informations required to operate the heliostat as a part of the solar thermal power plant. This study presents a heliostat control system designed and developed for the 1MW solar thermal power plant. We first define the functionality of heliostat control system. Then sun tracking controller as well as the sun tracking algorithm satisfying the required functionality have been developed. We tested the developed heliostat control system and it showed a good performance in regulation of heliostat motion and communication.

• Journal of the Korean Solar Energy Society
• /
• v.37 no.5
• /
• pp.27-37
• /
• 2017

In this study, an artificial solar simulator composed of a 2.5 kW Xe-Arc lamp and mirror reflector was used to carry out the solar thermal two step thermochemical water decomposition cycle which can produce high efficiency continuous hydrogen production. Through various operating conditions, the change of hydrogen production due to the possibility of a dual-zone reactor and heat recovery were experimentally analyzed. Based on the reaction temperature of Thermal-Reduction step and Water-Decomposition step at $1,400^{\circ}C$ and $1,000^{\circ}C$ respectively, the hydrogen production decreased by 23.2% under the power off condition, and as a result of experiments using heat recovery technology, the hydrogen production increased by 33.8%. Therefore, when a thermochemical two-step water decomposition cycle is conducted using a dual-zone reactor with heat recovery, it is expected that the cycle can be operated twice over a certain period of time and the hydrogen production amount is increased by at least 53.5% compared to a single reactor.

• Design & Manufacturing
• /
• v.13 no.1
• /
• pp.25-30
• /
• 2019

This paper presents the design strategy for the optimal RTM molds of Carbon Fiber Reinforced Plastic (CFRP) by carbon fiber draping and resin flow simulation. First, the mold shape and molding condition were determined considering the undercut and die face of the product in the draping simulation, which made the preliminary shape of the product by compressing the carbon fiber. After that, the diffusion behavior during the injection of resin in the mold was predicted by the resin flow simulation. Finally, the optimal mold shape was designed by selecting the locations of resin injection port and vent based on total results of simulations. In this paper, the mold of automotive side mirror case was selected as the representative product. Also, the actual mold was manufactured based on the simulation design to confirm the practicality of it. This study is expected to contribute to the industry as a technology to improve the reliability and productivity of CFRP producted by RTM process.

• Current Optics and Photonics
• /
• v.5 no.3
• /
• pp.298-305
• /
• 2021

Modern distance sensing methods employ various measurement principles, including triangulation, time-of-flight, confocal, interferometric and frequency comb. Among them, the triangulation method, with a laser light source and an image sensor, is widely used in low-cost applications. We developed an omnidirectional two-dimensional (2D) distance sensor based on the triangulation principle for indoor floor mapping applications. The sensor has a range of 150-1500 mm with a relative resolution better than 4% over the range and 1% at 1 meter distance. It rotationally scans a compact one-dimensional (1D) distance sensor, composed of a near infrared (NIR) laser diode, a folding mirror, an imaging lens, and an image detector. We designed the sensor layout and configuration to satisfy the required measurement range and resolution, selecting easily available components in a special effort to reduce cost. We built a prototype and tested it with seven representative indoor wall specimens (white wallpaper, gray wallpaper, black wallpaper, furniture wood, black leather, brown leather, and white plastic) in a typical indoor illuminated condition, 200 lux, on a floor under ceiling mounted fluorescent lamps. We confirmed the proposed sensor provided reliable distance reading of all the specimens over the required measurement range (150-1500 mm) with a measurement resolution of 4% overall and 1% at 1 meter, regardless of illumination conditions.

• Annals of Hepato-Biliary-Pancreatic Surgery
• /
• v.27 no.3
• /
• pp.322-327
• /
• 2023

Situs inversus totalis (SIT) is a rare condition in which cardiac and abdominal organs are inverted from their normal left-sided orientation. Mirizzi syndrome, characterized by the obstruction of the common hepatic duct or the common bile duct by gallstone, is a rare condition. Mirizzi syndrome co-occurrence in SIT patients is rare. Gallbladder in sinistroposition is extremely uncommon in SIT patients. We report a known case of diabetes, ventricular septal defect with transposition of the great arteries in a 32-year-old female who presented with jaundice, cholangitis, chills, and fever that had lasted for 10 days. She was confirmed to have SIT with type III Mirizzi syndrome following a series of diagnostic procedures. Primarily, endoscopic retrograde cholangiopancreatography along with common bile duct stenting was performed to initially reduce cholangitis. After an eight-week follow-up after the reduction of cholangitis, surgery was conducted. Mirror-imaged ports were used for the laparoscopic procedure, and the surgeon was on the patient's right side rather than the usual left side. The patient was discharged from the hospital following two days of uneventful healing.

• Korean Journal of Optics and Photonics
• /
• v.28 no.4
• /
• pp.153-157
• /
• 2017

An infrared camera and laser common-path optical system is applied to DIRCM (directional infrared countermeasures), to increase boresighting accuracy and decrease weight. Thermal effects of a laser beam in a common-path optical system are analyzed and evaluated, to predict any degradation in image quality. A laser beam with high energy density is absorbed by and heats the optical components, and then the surface temperature of the optical components increases. The heated optical components of the common-path optical system decrease system transmittance, which can degrade image quality. For analysis, the assumed simulation condition is that the laser is incident for 10 seconds on the mirror (aluminum, silica glass, silicon) and lens (sapphire, zinc selenide, silicon, germanium) materials, and the surface temperature distribution of each material is calculated. The wavelength of the laser beam is $4{\mu}m$ and its output power is 3 W. According to the results of the calculations, the surface temperature of silica glass for the mirror material and sapphire for the lens material is higher than for other materials; the main reason for the temperature increase is the absorption coefficient and thermal conductivity of the material. Consequently, materials for the optical components with high thermal conductivity and low absorption coefficient can reduce the image-quality degradation due to laser-beam thermal effects in an infrared camera and laser common-path optical system.

• (The)Study of the Eastern Classic
• /
• no.73
• /
• pp.281-302
• /
• 2018

The role of mind is very important in Xunzi's thought. The way is permanent rule of politics that is under the control of mind which is recognizing organ for both thinking and acknowledging things in his thought. Nevertheless the mind in Xunzi's thought has desire as an organ of body to be controlled. On the other hand, the mind has conflicting two fold aspects in the course of its recognition of things like storage and vacancy, movement and calmness, and two kinds of recognizing opinion against one object. And there are various evils in thinking system of mind. In a sense, the mind of human is to be cleaned and cultivated. Xunzi proposed managing energy and cultivating mind as a thinking system. Mengzi proposed to enliven vast-flowing energy and to cultivate mind through shortening desire, while Xunzi did managing energy and caring about mind for controlling other body systems and publicly recognizing things. In Xunzi's idea the mind in the recognition of things is similar to the water in bowl as a mirror for looking at any things, and thus it is imperative for us to sink grounds in mind for becoming good water mirror. In this need the grounds of human mind would be to be sunk and also the cultivation of it would be to be demanded. Ultimately there should need the recognition of mind that is cleaned and cultivated for brightly discovering the great principle and recovering the unchangeable way with a view to preparing the condition for national peace. This thesis, in this context, to approach the meaning of mind, its two fold aspects, and the necessity of it.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.16 no.1
• /
• pp.49-58
• /
• 1986

This study was designed to investigate the irradiation effects on the rat parotid gland, applied to the head and neck region. For this experiment, twenty-four rats, feeded under the even condition, were used as experimental animals. Twenty rats were used for experimental group and the rest were assigned to the control group. The experimental group was singly irradiated with 10Gray through Cobalt-60 radiotherapy device, Picker model 4M 60 (Field size; l2×5㎝, SSD; 50㎝, Depth; 1㎝). The experimental animals of both group were sacrificed each four animals in 2 days, 1week, 2weeks, 3weeks and 4weeks after irradiation. The specimens were examined through the light microscope using the H-E stain and H stain by routin procedure. The other specimens were observed under the fluorescence microscope using the B-O dichroic mirror and Y455 barrier filter after PA-ACH stain. 1. The results of this study were obtained as follows, The parotid acini were severely degenerated and the intraacinar spaces were widened. Within the acini, retained secretory granules and increased fibrosis were observed. Also the shape and the size of the acini showed very irregular atrophic degenerations. 2. The nuclei showed severe pyknosis, displacement and irregular aggregated appearance. 3. The tissue changes of the parotid acini were initiated after 2 days of irradiation and most severely appeared at the second week of irradiation, but almost returned to normal. 4. The salivary ducts of the parotid gland were severely atrophied, discontinued but initiated to regenerated after 3 weeks of irradiation.