• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3397-3406
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• 2012

Three types of spherulitic morphologies have been investigated in dual substrate mode of Belousov-Zhabotinsky (BZ) type reaction system. Prior to growth of spherulites, three distinct patterning behaviors have been observed sequentially during the reaction process. Initial and the early-phase of reaction showed the emergence of concentric ring-like wave patterns. A colloidal-state of reaction consists of numerous fine solid particles, which forms primarily some nucleation centers of dendritic characters. The nucleation centers were found to grow in sizes and shapes with the progress of reaction. It leads to growth of dendritic-like spherulitic crystal patterns. The resultant spherulites showed transitions in their morphologies, including sea-weeds and rhythmic spherulitic crystal patterns, by the effects substituted organic substrate and in the higher concentration of bromate-initiator respectively. The branching mechanism and crystal ordering of spherulitic textures were studied with help of optical microscope (OPM) and scanning electron microscope (SEM). Characteristics of crystal phases were also evaluated using X-ray diffraction (XRD) and differential thermal analysis (DTA). Results indicated that the compositions of reactants and crystal orderings were interrelated with morphological transitions of spherulites as illustrated and described.

• 한국재료학회지
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• 제15권5호
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• pp.301-305
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• 2005

We fabricated nickel silicide layers on whole non-patterned wafers from $p-Si(100)SiO_2(200nm)$/poly-Si(70 nm)mn(40 nm) structure by 40 sec rapid thermal annealing of $500\~900^{\circ}C$. The sheet resistance, cross-sectional microstructure, surface roughness, and phase analysis were investigated by a four point probe, a field emission scanning electron microscope, a scanning probe microscope, and an X-ray diffractometer, respectively. Sheet resistance was as small as $7\Omega/sq$. even at the elevated temperature of $900^{\circ}C$. The silicide thickness and surface roughness increased as silicidation temperature increased. We confirmed the nickel silicides iron thin nickel/poly-silicon structures would be a mixture of NiSi and $NiSi_2$ even at the $NiSi_2$ stable temperature region.

• 한국의류산업학회지
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• 제11권3호
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• pp.496-501
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• 2009

In this study, a kiwifruit-produced protease was used to improve the quality of the wool and silk fabrics. The wool and silk were treated with the actinidin from kiwifruit. Following this protease treatment, changes in the surface of a single yarn of the fabrics were observed via both an optical microscope and a scanning electron microscope (SEM). In order to determine the amount of dye uptake in the fabric, changes in the K/S value of the wool and silk were measured by spectrophotometric analysis. Also, we performed a tensile strength examination to determine variation in their mechanical properties. By increasing the protease treatment time to 48h, the dyeing properties of fabrics were enhanced, and the surfaces of the single yarns of the fabrics became smoother, because of the removal of soil and scale in them. However, no mechanical changes were detected in the fabrics. Thereby, we suggest that the kiwifruit-produced actinidin treatment can improve the quality of the fabrics.

• 한국기계가공학회지
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• 제16권4호
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• pp.76-82
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• 2017

The cylinder liner of a diesel engine is commonly made of gray cast iron. However, this cylinder liner can be damaged by the cavitation phenomenon in wet conditions. This cavitation has remained an unsolved problem until now. In this study, the cause of cavitation corrosion due to antifreeze solution was examined using a scanning electron microscope (SEM) and a 3D microscope. The necessary data to prevent the damage caused by cavitation erosion and the corrosion of gray cast iron cylinder liner was obtained. Analysis determined that the gray iron structure consists of an ${\alpha}-matrix$, flake graphite, and steadite. Cavitation erosion was initiated in the coarse flake graphite and propagated into the steadite with pitting. Under repetitive reaction conditions, the ${\alpha}-matrix$ was partially separated from the gray cast iron. This study is expected to be used as the basic data for the prevention of gray cast iron cavitation erosion and corrosion by controlling the graphite and steadite phases.

• 한국염색가공학회지
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• 제27권3호
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• pp.219-227
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• 2015

This study aims to propose a method to reduce hair damage after investigating the following: the factors which vary depending on hair treatment conditions; the degree of hair damage in the bleached sample; and an analysis of the effects of a perm on wave formation. To determine the effects of these treatment types, hair bleach was mixed with the hair treatment, and hair damage and formation of permanent waves were examined. Using a scanning electron microscope, in addition, morphological changes were analyzed and the following results were obtained: After mixing natural powder(2.5g) and hair cream(2.5g) and bleaching the mixture, it was compared to the scale structure of untreated hair. When 5g of natural powder was mixed and bleached, a clear layer was observed among cuticle scales, showing the effects of hair treatment. Therefore, this confirms that the effects of hair treatment were most notable when grain powder was mixed with hair cream. Once hair is damaged, it is almost impossible to regain its original state. When chemical agents are used, therefore, it is important to consider the possible hair damage they cause.

• 동력기계공학회지
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• 제4권4호
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• pp.48-53
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• 2000

This study was aimed at observing the influence of laser irradiation on a $ZrO_2-8%Y_2O_3$ ceramic coating layer fabricated by plasma spraying. The $ZrO_2-8%Y_2O_3$ ceramic powder was plasma sprayed onto SS400 carbon steel substrate and laser irradiated on the coating layer under various conditions of laser power and beam diameters. As to the as-sprayed specimen and laser-treated specimen, a hardness test and a microstructure analysis were performed. Hardness was measured by a microhardness tester; microstructure was observed by an optical microscope and a scanning electron microscope. The result was that the microstructure of the laser-irradiated coating layer was dense; porosities almost disappeared and hardness increased. It was also observed that microcracks occured in the laser-irradiated coating layer.

• 복식
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• 제58권9호
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• pp.129-141
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• 2008

Jikgeum(woven with supplementary golden wefts) hyungbae(rank badge) of danryung(official uniform) excavated from Im Backryung'tomb($1498{\sim}1546$) of the Joseon dynasty($1392{\sim}1910$) at Goyang, Gyunggi-Do in 2007, was in a critical condition because of serious collapse of substrate in metal thread. For conservation of hyungbae, metal thread was examined by different scientific methods(Light Microscope, Scanning Electron Microscope and Energy Dispersive X-Rray Spectrometry(SEM-EDS), Fourier Transform Infrared Spectroscopy(FT-IR)). Analytical data showed that metal thread was gilt membrane strip composed of gold leaves and proteinaceous substrate which was probably parchment. To protect collapse of substrate, 1% solution of Paraloid B-72 was infilterated into substrate for consolidation of substrate and it was adhered to warp of fabric in hyungbae, before wet cleaning. After wet cleaning, the most of the gold leaves were restored, which was confirmed by both the examination with the naked eye and the microscopic examination.

• 한국표면공학회지
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• 제50권5호
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• pp.332-338
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• 2017

In this study, we evaluated tendency and degree of corrosion damages of Inconel 600 after chemical decontamination treatments under three different conditions. In the decontamination processes, the oxidation and reduction were performed as one cycle. Each process was continued up to 5 cycles. Characteristics of corrosion under decontamination processes were evaluated by Tafel analysis and weight loss. Characteristics of surface damage were observed by scanning electron microscope(SEM) and three-dimensional(3D) microscope. As the cycle proceeded, weight loss and corrosion current density increased. Intergranular corrosion damage occurred on the surface of the materials. The result revealed that the surface of Inconel 600 was attacked by the strong acid solution under all chemical decontamination processes, but the degree of the corrosion damage was different depending on the processes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.576-577
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• 2005

In this paper, the oxidization characteristics were analyzed according to the shapes of Residual Current Protective Device(RCD) contacts. RCD is an electrical safety device specially designed to immediately switch the electricity off when electric leakage is detected at a level harmful to a person using electrical equipment. The shapes of RCD contacts are a little bit different according to the models. When RCD is turned on, stationary and moving contact do not fit together. So, it can cause the increase of contact resistance. To discover the deterioration characteristics of RCD contacts by switching repetition, the contacts were analyzed by stereo microscope, Scanning Electron Microscope(SEM) and Energy Dispersive X-ray Spectrometer(EDS).

• Journal of Magnetics
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• 제18권3호
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• pp.311-316
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• 2013

Digital image processing has increasingly been implemented in nanostructural analysis and would be an ideal tool to characterize the morphology and position of self-assembled magnetic nanoparticles for high density recording. In this work, magnetic nanoparticles were synthesized by the modified polyol process using $Fe(acac)_3$ and $Pt(acac)_2$ as starting materials. Transmission electron microscope (TEM) images of as-synthesized products were inspected using an image processing procedure. Grayscale images ($800{\times}800$ pixels, 72 dot per inch) were converted to binary images by using Otsu's thresholding. Each particle was then detected by using the closing algorithm with disk structuring elements of 2 pixels, the Canny edge detection, and edge linking algorithm. Their centroid, diameter and area were subsequently evaluated. The degree of polydispersity of magnetic nanoparticles can then be compared using the size distribution from this image processing procedure.