• Journal of Powder Materials
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• v.10 no.3
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• pp.181-185
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• 2003

Resistance sintering under ultra-high pressure if developed to fabricate W-Cu composite containing 5 to 80v/o copper. The consolidation was carried out under pressure of 6 to 8 GPa and input power of 18 to 23 kW for 50 seconds. The densification effect and microstructure of these W-Cu composites are investigated. The effect of W particle size on ,sintering density was also studied. The micro hardness was measured to evaluate the sintering effect.

• Journal of Ocean Engineering and Technology
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• v.18 no.2
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• pp.77-82
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• 2004

The purpose of this study is to develop a nesting algorithm, using a genetic algorithm to optimize nesting order, and modified No Fit Polygon(NFP) methodology to place parts with the order generated from the previous genetic algorithm. Various genetic algorithm techniques, which have thus far been applied to the Travelling Salesman Problem, were tested. The partially mapped crossover method, the inversion method for mutation, the elitist strategy, and the linear scaling method of fitness value were selected to optimize the nesting order. A modified NFP methodology, with improved searching capability for non-convex polygon, was applied repeatedly to the placement of parts according to the order generated from previous genetic algorithm. Modified NFP, combined with the genetic algorithms that have been proven in TSP, were applied to the nesting problem. For two example cases, the combined nesting algorithm, proposed in this study, shows better results than that from previous studies.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.6
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• pp.636-641
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• 2009

Recently, expansion of micro-technology parts requires micro-precision machining technology. Micro-groove machining is important to fabricate micro-grating lens and many micro-parts such as microscope lens, fluidic graphite channel etc. Conventional groove fabrication methods such as etching and lithography have some problems in efficiency and surface integrity. But, mechanical micromachining methods using single crystal diamond tools can reduce these problems in chemical process. For this reason, microfabrication methods are expected to be very efficient, and widely studied. This study deals with machinability in micro-precision V-grooves machining of nickel plated layer using non-rotational single crystal diamond tool and 3-axis micro stages. Micro V-groove shape, chip formation and tool wear were investigated for the analysis of machinability of Ni plated layer.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.1
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• pp.110-115
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• 2009

In general, the radial error motion of a machine tool spindle system is effected on the accuracy of the parts to be made. This paper presents in milling process an investigation into spindle rotational accuracy effects on surface roughness of processing parts. We experimented the effects on spindle rotational accuracy in milling process by cutting AL 7075 workpiece at various rotational speed. In order to analyze the effects of rotational accuracy on surface roughness, we proposed the method using iSIGHT's RBF Approximation. The proposed method can be used fur anticipating the surface roughness when some spindle rotational accuracy experiments could be done in milling process.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.207-208
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• 2006

In this experimental work, the development of a multicomponent binder system based on high density polyethylene (HDPE) and paraffin wax for Powder Injection Molding of Alumina $(Al_2O_3)$ parts was carried out. The optimum composition of the injection mixture was established through mixing torque measurements and a rheological study. The maximum powder loading was 58 vol%. The miscibility of organic components and the optimum injection temperature was evaluated by thermal characterization of binder and feedstock. The thermal debinding cycle was developed on the basis of thermogravimetrical analysis of the binder. After sintering the densities achieved were closed to 98% of the theoretical one.

• Natural Product Sciences
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• v.18 no.3
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• pp.166-170
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• 2012

The purification of the MeOH extract from the aerial parts of Erythronium japonicum using column chromatography furnished a new megastigmane glucoside, erthrojaponiside (1), together with six known megastigmane derivatives (2 - 7). The structure of the new compound (1) was determined through 1D and 2D NMR spectral data analysis and chemical means. The isolated compounds (1 - 7) were tested for cytotoxicity against four human tumor cells in vitro using a Sulforhodamin B (SRB) bioassay.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.33
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• pp.63-70
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• 1995

Most of small-to-medium sized companies use computer to manage and control their manufacturing system. However, it is real hard to find a company which uses the system properly. There are several reasons. First of all, appropriate software to satisfy user's needs is not available and there is lack of mind to computerize. Therefore, this paper focuses to show difficulties which they will encounter, develop a model of computerized production management system and define proper level of computerization. An experimental system has been developed for an auto-parts manufacturing company using IBM-PC in the environment of MS-DOS and CA-Clipper.

• Food Science and Preservation
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• v.18 no.5
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• pp.739-745
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• 2011

The major objective of this study was to investigate the antioxidant activities of methanolic extracts from different parts (flower, leaf stem, and root) of Chrysanthemum zawadskii by employing various in-vitro assay systems. The extraction yields from the flower, leaf stem, and root were 18.347, 12.93, and 11.33-----, respectively. The total polyphenol content was highest in the flower (17.16 mg/100 g) and lowest in the root (11.33 mg/100 g). The antioxidant activities were raised within creasing amounts of extracts, and the extracts from the flower showed the highest effect on the superoxide anion radical scavenging, metal chelating on ferrous ions and reducing power. In addition, the leaf stem also showed good antioxidant activity in various systems. These results suggest that the methanolic extracts from the flower and leaf stem possess excellent antioxidant activities and may thus serve as potential sources of natural antioxidants.

• The Korea Journal of Herbology
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• v.36 no.5
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• pp.47-57
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• 2021

Objective : For the purpose of developing Convoivulaceae plants recorded in Korean Herbology in Korea, the literatures of the successive generations have been thoroughly investigated to prepare this article. Methods : Books and research papers about Herbology which published at Korea and other countries were examined. Results : A list was made about Convoivulaceae plant which were cultivated or grew naturally in Korea, after investigated the data on domestic and foreign Convoivulaceae plants. Convoivulaceae(grew in Korea) were divided into 6 classes with 18 species. Out of those, 6 classes with 13 species were found serviceable which indicates approximately 72% of all. Out of all 18 species of Convoivulaceae family, Calystegia genus were found 6 species, which were shown the most. Among 4 genus of Calystegia species, medicinal plants were all one species each. Out of all serviceable parts in Convoivulaceae, Herb·Radix·Tuber·Semen·Flower·Stem and Folium parts took first place as 8 species. There are 2 species toxic, the survey said. 6 Classifying medicinal plants among the Convoivulaceae plants by part, whole Herbs are found to be 8 separate species each. When it comes to the nature of taste, 10 kinds of taste without action and 7 kinds of sweet taste are the most common. For channel tropism, kidney channel has the largest number of 7 types. Conclusion : A total of 6 genera and 18 species of Convoivulaceae was found in the Korean among which 6 genera and 13 species(approximately 72%) were medicinal plants. Two species toxic drugs were detected.

• The Korean Journal of Food And Nutrition
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• v.12 no.2
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• pp.113-118
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• 1999

Ten specimens of pufferfish Lagocephalus gloveri(called Gumeun-mibog in Korean) were purchased at a fish market in Pusan Korea. The pufferfishes were immediately frozen packed in ice boxes transpor-ted to our laboratory and then dissected in to four parts. The tissues were homoginized after adding with chloroform: methanol mixture solution and storaged at cool and dark place to extract total lipid. The total lipid contents were 29,34∼36.54% in liver 4.95∼6.11% in intestine 1.08∼1.60% in skin and 0.23∼0.38% in muscle of the pufferfish respectively. The contents of DHA and EPA were higher in the total lipids of livers showing 15.99% DHA and 3.04% EPA. The other fatty acids in the total lipids of liver were mainly composed of palmitic acid(16:0) palmitoleic acid(16:1) stearic acid(18:0) and oliec acid(18:1) Furthermore the contents of neurtral lipids were 95.45% and those of phospholipids and glycolipids were 1.45 and 3.09% respectively. Main fattty acids of the neutral lipid were composed of palmitic acid(16:0) stearic acid(18:0) oleic acid(18:1) oleic acid(18:1) EPA(20:6) and DHA(22:6) The contents of DHA and EPA were 16.62 and 2.41% respectvely. From these results of toxicity in the raw liver the tissue was judged to be nontoxic before and after extracting of total lipid.