• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.852-857
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• 2011

The shipbuilding industry needs automation and mechanization to solve reduction of skilled workers and labor shortage. Ship manufacturing process is the lack of automation than standardized manufacturing field. In this paper, we design and development an process automation system for hand rail production. Mechanical parts of the cutting process was designed with efficiency, productivity and reliability, CATIA and ANSYS, the stability of the mechanical structure was confirmed. System control using a PCNC controller to provide an open and scalable, and operate using touch-screen display control and monitoring of the system was performed. The automatic system successfully passed the driving test and processing test, and it showed an excellent performance.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.224-225
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• 2000

Transparent and hard materials such as sapphire are used for many industrial applications as optical windows, hard materials on mechanical contact against abrasion, and substrate materials for opto-electronic semiconductor devices such as blue LED and blue LD etc. The materials should be cut along the proper shapes possible to be used for each application. In case of blue LED, the blue LED wafer should be cut to thousands of blue LED pieces at the final stage of the manufacturing process. The process of cutting the wafer is usually divided into two steps. The wafer is scribed along the proper shapes in the first step. It is inserted between transparent flexible sheets for easy handling. And then, it is broken and split in the next step. Harder materials such as diamonds are usually used to scribe the wafer, while it has a problem of low depth of scribing and abrasion of the harder material itself. The low depth of scribing can induce failure in breaking the wafer along the scribed line. It was also known that the expensive diamond tip should be replaced frequently for the abrasion. (omitted)

• Korean Journal of Veterinary Service
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• v.21 no.4
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• pp.401-405
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• 1998

A male badger which showed depression and bloody diarrhea was submitted to Iksan Branch of Chonbuk Veterinary Service Laboratory for necropsy on May 1998. Grossly, paleness of the mucous membranes was observed and the small intestinal contents were hamorrhagic. The numerous tiny hookworms, sized in 5-10 mm and greyish-white in color, attached to the intestinal mucosa. Male bursa was well developed. Histologically, intestinal lumen was filled with hemorrhagic contents, which contained worms. The epithelial cells of the villi were underwent degeneration and lamina propria was infiltrated by lymphocytes and plasma cells, and goblet cells were hyperplastic. There were rounded cutting plates in the funnel-shaped buccal capsule and transverse striation on sheath in hookworm, ultrastructurally, which were consistent with Uncinaria sp. The shape of eggs were ellipsoidal and morula, and some eggs contained a mobile larva. It was concluded that this badger was infected with Uncinaria.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.59-63
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• 2021

Upper electrode is one of core parts using plasma etching process at semiconductor. The purpose of this study is to analyze effects of cutting conditions for mechanical machining of silicon upper electrode. For this research, surface roughness of machined workpiece and depth of damage inside of silicon electrode are experimented and analyzed and different values of feed rate and depth of cut are applied for the experiments. From these experiments, it is verified that the surface roughness and internal damaged layer get worse according to take more fast feed rate. In conclusion, cutting condition is very important factor for machining. Results of this study can use to develop various parts which are made from single crystal silicon and affect various benefits to the semiconductor industry for better productivity.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.72-81
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• 2009

This paper presents quasi-resonant type high power factor ac power supply for atmospheric pressure plasma cleaning system adopting three phase PFC boost converter and it's control method. The presented ac power supply consists of single phase H-bridge inverter, step-up transformer for generating high voltage and three phase PFC boost converter for high power factor on source utility. Unlikely to the traditional LC resonant converter, the propose one has an inductor inside only. A single resonant takes place through the inside inductor and the capacitor from the plasma load modeled into two series capacitor and one resistance. The quasi-resonant can be achieved by cutting the switching signal when the load current decrease to zero. To obtain power control ability, the propose converter controlled by two control schemes. One is the changing output pulse period scheme in the manner of PFM(Pulse Frequency Modulation) control. On the other, to provide more higher power to load, the DC rail voltage is directly controlled by the 3-phase PFC boost converter. The significant merits of the proposed converter are the uniform power providing capability for high quality plasma generation and low reactive power in AC and DC side. The proposed work is verified through digital simulation and experimental implementation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.9
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• pp.88-93
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• 2019

The purpose of this study is to analyze the flow of a system that collects fumes in the plasma cutting machine widely used in industrial sites. A plan for improving the fume collection facility of an industrial plant using a large plasma cutter was investigated through flow analysis. Results show that it is effective to capture and suck fumes from a nearby cutter. If more hoods were installed near the cutter, fumes that were scattered internally could be removed effectively. In addition, if suction inflow was increased, the fumes could be removed more effectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.36-41
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• 2017

In this paper, $Si_3N_4/hBN$ ceramics with various hexagonal boron nitride (hBN) contents (0, 10, 20, or 30 wt%) were fabricated via spark plasma sintering (SPS) at $1500^{\circ}C$, 50MPa, and 10m holding time. The material properties such as the relative density, hardness, and fracture toughness were systematically evaluated according to the hBN content in the $Si_3N_4/hBN$ ceramics. The results show that relative density, hardness, and fracture toughness continuously decreased as the hBN content increased. In addition, peak-step drilling (with tool diameter $500{\mu}m$) was performed to observe the effects of hBN content in micro-hole shape and cutting force. A machined hole diameter of $510{\mu}m$ (entrance) and stable cutting force were obtained at 30 wt% hBN content. Consequently, $Si_3N_4/30wt%$ hBN ceramic is a feasible material upon which to apply semi-conductor components, and this study is very meaningful for determining correlations between material properties and machining performance.

• Journal of Adhesion and Interface
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• v.19 no.4
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• pp.154-162
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• 2018

Plasma treatment and corona treatment have been used for surface modification of polydimethylsiloxane (PDMS) film by activating its surface with the -OH group. Adhesion promoter or coupling agent was also used to improve adhesion of PDMS film with various materials. However, obtained hydrophilicity onto the surface of PDMS films with those processes was transient and vulnerable. In this study, a new alkoxysilane-functionalized acrylic polymer precursor was first synthesized by copolymerization process, and then was reacted with HO-terminated PDMS through condensation reaction to prepare a new surface modifier for PDMS film. The structure and molecular weight of the prepared surface modifier were confirmed by 1H-NMR and GPC measurement. Surface properties of surface modifier-coated PDMS films were also investigated by using XPS, ATR and WCA analysis. The adhesion between the PDMS film and the surface modifier was tested using cross-cut test.

• Journal of the Optical Society of Korea
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• v.7 no.4
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• pp.230-233
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• 2003

This study describes the conceptual design of a soft x-ray microscope system based on a laserbased source for biomedical application with high resolution (${\leq}$50nm). The laboratory scale soft x-ray microscope consists of high power laser plasma x-ray source and grazing incidence mirrors with high reflectivity. The laser plasma source used for developing this system employs Q-switched Nd-YAG pulsed laser. The laser beam is focused on a tantalum (Ta) target. The Wolter type I mirror was used as condenser optics for sample illumination and as objective mirror for focusing on a detector. The fabrication of the Wolter type I mirror was direct internal cutting using ultraprecision DTM. A hydrated biological specimen was put between the two silicon wafers, the center of which was $Si_3N_4$ windows of 100㎚ thickness. The main issues in the future development work are to make a stable, reliable and reproducible x-ray microscope system.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.110-114
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• 2011

Polymeric films of high chemical stability and mechanical strength covered with a thin metallic film have been extensively used in various fields as electric and electronic materials. In this study, we have chosen polypropylene (PP) as the polymer due to its outstanding chemical resistance and good creep resistance. We coated thin nickel film on PP films by the electroless plating process. The surfaces of PP films were pre-treated and modified to increase the adhesion strength of metal layer on PP films, prior to the plating process, by an environment-friendly process with atmospheric plasma generated using dielectric barrier discharges in air. The surface morphologies of the PP films were observed before and after the surface modification process using a scanning electron microscope (SEM). The static contact angles were measured with deionized water droplets. The cross-sectional images of the PP films coated with thin metal film were taken with SEM to see the combined state between metallic and PP films. The adhesion strength of the metallic thin films on the PP films was confirmed by the thermal shock test and the cross-cutting and peel test. In conclusion, we made a composite material of metallic and polymeric films of high adhesion strength.