• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1507-1510
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• 2005

This study was carried out as a part of the research on the development of a maskless and electroless process for fabricating metal micro/nanostructures by using a nanoindenter and an electroless deposition technique. $2-\mu{m}-deep$ indentation tests on Ni and Cu samples were performed. The elastic recovery of the Ni and Cu was 9.30% and 9.53% of the maximum penetration depth, respectively. The hardness and the elastic modulus were 1.56 GPa and 120 GPa for Ni and 1.49 GPa and 100 GPa for Cu. The effect of single-point diamond machining conditions such as the Berkovich tip orientation (0, 45, and $90^{\circ}$) and the normal load (0.1, 0.3, 0.5, 1, 3, and 5 mN), on both the deformation behavior and the morphology of cutting traces (such as width and depth) was investigated by constant-load scratch tests. The tip orientation had a significant influence on the coefficient of friction, which varied from 0.52-0.66 for Ni and from 0.46-0.61 for Cu. The crisscross-pattern sample showed that the tip orientation strongly affects the surface quality of the machined area during scratching. A selective deposition of Cu at the pit-like defect on a p-type Si(111) surface was also investigated. Preferential deposition of the Cu occurred at the surface defect sites of silicon wafers, indicating that those defect sites act as active sites for the deposition reaction. The shape of the Cu-deposited area was almost the same as that of the residual stress field.

• Journal of the Korean Vacuum Society
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• v.22 no.5
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• pp.262-269
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• 2013

Though focused ion beam (FIB) is one of the candidates to fabricate the nanoscale patterns, precision milling of nanoscale structures is not straightforward. Thus this poses challenges for novice FIB users. Optimal determination in FIB parameters is a crucial step to fabricate a desired nanoscale pattern. There are two main FIB parameters to consider, beam current (beam size) and dose (beam duration) for optimizing the milling condition. After fixing the dose, the proper beam current can be chosen considering both total milling time and resolution of the pattern. Then, using the chosen beam current, the metal nano hole structure can be perforated to the required depth by varying the dose. In this experiment, we found the adequate condition of $0.1nC/{\mu}m^2$ dose at 1 pA Ga ion beam current for 100 nm thickness perforation. With this condition, we perforated the periodic square array of elliptical nano holes.

• Korean Journal of Materials Research
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• v.2 no.1
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• pp.76-82
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• 1992

Deposition of $TEOS-O_3$ oxide film as inter-metal dielectric layer shows the substrate dependency according to the substrate material and pattern density and pitch size. To minimize substrate and Pattern dependency, TEOS-base and $SiH_4-base$ Plasma oxide were predeposited as underlying material on the substrate. The substrate dependency of $TEOS-O_3$ oxide film was more significant on TEOS-base plasma oxide than on $SiH_4-base$ plasma oxide. The dependency of $TEOS-O_3$ oxide film was remarkably reduced, or nearly eliminated, by $N_2$plasma treatment on TEOS-base plasma oxide, which appears to be caused by the O-Si-N structure, observed on the the surface of TEOS-base plasma oxide.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.6980-6985
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• 2014

A micro-conductive pattern was fabricated on an insulating substrate ($SiO_2$) surface using a laser direct writing method. In the LIFT process, when the laser beam irradiates a thin metal film, the photon energy is absorbed by the film and converted to thermal energy, and the thermal decomposition reaction produced by the resulting heat conduction forms a deposit on the substrate. The resistivity of the micro-electrodes deposited through LIFT process with and without polymer coating was measured. The results showed that the electric conductivity of the micro-pattern and micro-structure can be increased approximatly two times when the deposited micropattern is fabricated through a LIFT process with a polymer coating, compared to the case without a polymer coating.

• Journal of Sensor Science and Technology
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• v.23 no.1
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• pp.15-18
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• 2014

We present gas sensing performance based on $2{\times}2$ sensor array with four different elements ($TiO_2$, $SnO_2$, $WO_3$ and $In_2O_3$ thin films) fabricated by rf sputter. Each thin film was deposited onto the selected $SiO_2$/Si substrate with Pt interdigitated electrodes (IDEs) of $5{\mu}m$ spacing which were fabricated on a $SiO_2$/Si substrate using photolithography and dry etching. For 5 ppm $NO_2$ and 50 ppm CO, each thin film sensor has a different response to offers the distinguishable response pattern for different gas molecules. Compared with the conventional micro-fabrication technology, $2{\times}2$ sensor array with such remarkable response pattern will be open a new foundation for monolithic integration of high-performance chemoresistive sensors with simplicity in fabrication, low cost, high reliablity, and multifunctional smart sensors for environmental monitoring.

• Journal of the Korean Society of Costume
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• v.66 no.1
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• pp.1-12
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• 2016

Najang was the central Seori, affiliated to the Ministry of War during the Joseon dynasty. The objective of this study is to research the existing authentic Najang costumes from the late-Joseon dynasty by examining factors, such as the composition of the costume, size, and method of creation, and attempt to replicate it. The Leipzig Grassi Museum in Germany possesses an official uniform of Najang from the late-Joseon dynasty, and we visited the museum in May of 2013 to examine it for the study. Written records, or Uigwe, and other pictorial data from the Joseon Dynastry describe the Najang wearing black or navy clothing with white decoration and pointy hats. The most notable characteristic of the Najang uniform is that it has the cotton cords pattern. The hat has a brass ball attached, which was worn with the ball facing the front in the early Joseon Dynasty, and was worn facing the back in the later years. They usually wore black head cloths (Heuk-geon), but would attach feathers on the black hats (Heuk-rip) for special occasions. The Najang uniform preserved in the Leipsiz Grassi Muesim does not exist in Korea. It is made of cotton. The cotton cord pattern of the uniform of Najang was made using single-ply cords and double-ply cords. The hat worn by Najang is in a form of a cone that becomes narrower towards the top or is in a form with wide and open end. It was made of oiled paper covered with hemp, and two circular metal disks were attatched at the rear.

• Composites Research
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• v.17 no.5
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• pp.1-6
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• 2004

Composite pressure vessels with HDPE (high density polyethlyne) liner with metal boss at each end were developed by Filament Winding Process. The vessel is composed of a dome-shaped part at each end and a cylinder-shaped part at the middle of the vessel. The environmental tests carried out for possible vessel materials such as High Density Polyethlyn (HDPE), resins and reinforcing fibers up to a year showed no significant damages. The boss was designed to minimize the gas leak which was verified by FEM analysis. Most ideal fiber tension was obtained by experimental method and the fiber volume fraction, $\textrm{V}_{f}$, obtained by image analyzer were 55.4 % in cylinder and 55.6 % in dome parts, respectively. Winding pattern is programmed to control the composite thickness in the dome areas such that the failure of the vessel may occur in the cylinder. During the cure, the vessel was rotated and a constant internal pressure of 0.62 bar was applied. From this, the vessel's burst pressure is improved by 28 %. The burst and fatigue tests for under-wound and fully wound vessel showed satisfactory results.

• Journal of the Korean Society of Clothing and Textiles
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• v.19 no.2
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• pp.297-316
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• 1995

The system and symbolizing ideologic meanings of the metallic Kwon in period of the Three-Kingdoms were comsidered by comparing to their cultural path and structal styles throughout the tree and the deer worship ideology. The results of this study are as followings; Firstly, the beginning of the Korean, mostly northern style was originated from metal tools of the Bronze age in BC 6c-7c. The maJ;lufature of the metallic adornment brought the pr-evailing use of metallic objects of craftwork after the supply of ironmongery. Secondly, the cultmal characteristics of the metallic Kwan in the kor-ean Peninsula were influenced f-rom the northern chinese tribes, Momg Go, Hung No, and Sien-pi who were transmitted from the scythian of the southern Russia having a prefenence for gold. Thir-dly, the metallic Kwon of the Kogmgo and the Baekje era was ideologically based on the ar-t of Buddism of the pattern of blazing flame, the carved pattern of flower- of herb, and the honey. sukle which were tramsmitted to china thr-ough the silk noad. Fourthly, the metallic K wam of the silla era consisted of the tree and the antler types in closely nelated to the tree and the deer ideology which were based on the background of shamanism. It should be raid that the metallic Kwan of the silla esa are connected to the type of nor-them ancient K wan. Lasthy, the metallic Kwan-Mo of the Kaja esa was mosthy original type of flower of herb even if kome of these ar-e similiar to the tree adornment type of silla. This type of flower of herb in based on the scythian type with a statue im silveer founded at Alexandnopol in the southern russia.

• Journal of Ginseng Research
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• v.30 no.3
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• pp.106-111
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• 2006

Adverse changes in individual's biochemistry under heavy metal stress are directly linked with its metabolic activity and health status. The present investigation highlights the differences in protecting role of Panax ginseng extract against mercuric chloride induced alterations in serum proteins. The assessment was based on dividing fifty albino rats into two sets, one for acute and the other for sub-acute study. All the sets had five groups with five albino rats in each i.e. control group, mercuric chloride treated group, Panax ginseng extract treated group, mercuric chloride followed by Panax ginseng extract treated group and Panax ginseng extract followed by mercuric chloride treated group. Mercuric chloride was given orally 0.926 mg/kg body weight for acute set and 0.044 mg/kg body weight for sub-acute set after LD50 (9.26 mg/kg body weight) determination by probitt analysis. 10 mg/kg body weight Panax ginseng extract was given in both acute and sub-acute sets after incorporating safety trials. The control group received tween-20 and distilled water only. The result exhibited significantly reduction (P<0.01) in serum protein, albumin and globulin following mercuric chloride intoxication whereas significant (P<0.01) enhancement in other groups with Panax ginseng extract as an ingredient confirming its protective role. All serum samples were also electrophoresed in 10% SDS with standard marker using discontinuous buffering system. Gradual disappearance of alpha-2 and beta-1 globulin bands from electrophoretic pattern was observed, while a single sharp band was observed between beta-2 and gamma globulin in serum protein pattern of acutely mercuric chloride treated rats. However, this band could not be visualized in sub-acute studies. Panax ginseng extract exhibits a better protection after acute intoxication.

• Journal of the Korean Society of Safety
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• v.27 no.3
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• pp.57-62
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• 2012

The purpose of this paper is to find dangerous factors of a water purifier when water leaks due to inappropriate use and analyze the patterns of damaged parts in order to provide data for the examination of the cause of the problem. If the water purifier is inspected and managed by a non-specialist, when the FLC(Float Level Controller) at the top is inclined, water leakage may occur to the water purifier. The leaked water flows onto the cables and hoses and enters the thermostat terminal, heater, PCB, power supply connection connector, etc., becoming a dangerous factor that may cause a system failure, fire, etc. Due to the water that entered the input terminal, low noise and white smoke were generated at first. However, the flame gradually propagated due to the continuous inflow of moisture. It was found that when moisture reached the PCB, a carbonized conductive path was formed at the varistor terminal, input terminal, semiconductor device terminal, etc., and the flame became larger, which might result in a fire. From the metal microscope analysis of a damaged condenser terminal, it was found that the amorphous structure unique to copper cable disappeared, and voids, boundary surface and disorderly fine particles occurred. Also, in the case of the connector into which moisture penetrated, fusion and deformation occurred at the cable connection clips. The result of analysis of the power supply cable connector using a thermal image camera showed that most of the heat was generated from the cable connection clips and the temperature at the connection center was normal.