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        검색결과 14

        1.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates the microstructure and wear properties of cermet (ceramic + metal) coating materials manufactured using high velocity oxygen fuel (HVOF) process. Three types of HVOF coating layers are formed by depositing WC-12Co, WC-20Cr-7Ni, and Cr3C2-20NiCr (wt.%) powders on S45C steel substrate. The porosities of the coating layers are 1 ± 0.5% for all three specimens. Microstructural analysis confirms the formation of second carbide phases of W2C, Co6W6C, and Cr7C3 owing to decarburizing of WC phases on WC-based coating layers. In the case of WC-12Co coating, which has a high ratio of W2C phase with high brittleness, the interface property between the carbide and the metal binder slightly decreases. In the Cr3C2-20CrNi coating layer, decarburizing almost does not occur, but fine cavities exist between the splats. The wear loss occurs in the descending order of Cr3C2-20NiCr, WC-12Co, and WC-20Cr-7Ni, where WC-20Cr-7Ni achieves the highest wear resistance property. It can be inferred that the ratio of the carbide and the binding properties between carbide–binder and binder–binder in a cermet coating material manufactured with HVOF as the primary factors determine the wear properties of the cermet coating material.
        4,000원
        2.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to consider the relation between the deciding factors of local identity and local image improvement. To achieve this purpose, the deciding factors of local identity have been set as the following four: historical identity, cultural identity, (nature) scenery identity, and industrial identity. The writer has established a model to represent the relation between these factors and the local image improvement, namely 'Visitor Satisfaction' and 'Revisit Intentions', and framed a hypothesis for empirical verification. The study results are as follows: First, the deciding factors of local identity which this study addressed are empirically proven to have a significant effect on the visitor satisfaction and the intention to revisit in which is it likely that the greater the impact of the deciding factors, the higher the visitor satisfaction and revisit intentions would be. Second, the deciding factors of local identity, it appears that the 'historical identity' factor had the largest impact on the visitor satisfaction, and the 'cultural identity' factor had the largest impact on the revisit intentions. Therefore, of the four deciding factors, the 'historical identity' should be considered the highest priority to increase the visitor satisfaction, and the 'cultural identity' should be considered the highest priority to increase the revisit intentions. Third, based on the verification of the relation between the visitor satisfaction and revisit intentions, it can be presumed that the greater the visitor satisfaction, the higher the revisit intentions would be.
        5,100원
        3.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop a dummy in an environment similar to the human body, to prepare a standard for evaluation and to present the process of the production in order to evaluate the performance of the robot that can detect the persons needing rescue in a confined space, who are difficult for fire-fighting officials to rescue in case of fire and disaster. As a result, a standard for evaluation was developed and standardized into four parts ‘Normal,’ ‘Risk Stage 1,’ ‘Risk Stage 2’ and ‘Risk Stage 3’based on the number of breath cycles, carbon dioxide concentration, core temperature and criteria for hearing to recognize the voice. In addition, in order to produce a dummy, fever, breathing capacity and voice output function were compared and analyzed. This study has significance that it built up basic data of the method of producing the actual dummy, by presenting characteristics and controlling methods using the waterproof insulation heating coil for the function, solenoid valve for the consecutive output of breathing capacity and USB program sound board for voice output.
        4,000원
        4.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study empirically analyzed the influence of media on a visitor's satisfaction and re-visit by setting up 5 sorts of exhibition media as text, docent, virtual museum, website and Smartphone App based on practical exchange and communication between a visitor and an exhibition provider. The research results are as follows: First, all these 5 sorts of media suggested by this study were found to be able to have an influence on a visitor's satisfaction and re-visit. Second, it was found that the factors preferentially affecting a visitor's satisfaction and re-visit were 'Docent' and 'Website' factors. Accordingly, it is judged that it's necessary to more preferentially consider 'Docent' and 'Website' factors than the other factors in order to increase a visitor's satisfaction and re-visit. Third, it's possible to interpret that the bigger a visitor's satisfaction, the higher a visitor's intention to re-visit through the verification that a visitor's satisfaction will have a significant influence on a visitor's re-visit. The implication of this study lies in the fact that this study attempted at an integrated approach by analyzing the relative size of the influence through across-the-board suggestion of influential factors on a museum visitor's satisfaction and re-visit.
        4,500원
        5.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effect of heat treatment environment on the microstructure and properties of tantalum coating layer manufactured by kinetic spraying was examined. Heat treatments are conducted for one hour at 800oC, 900oC, and 1000oC in two different environments of vacuum and Ar gas. Evaluation of microstructure and physical properties are conducted. High density α- tantalum single phase coating layer with a porosity of 0.04% and hardness of 550 Hv can be obtained. As heat treatment temperature increases, porosity identically decreases regardless of heat treatment environment (vacuum and Ar gas). Hardness of heat treated coating layer especially in Ar gas environment deceases from 550 Hv to 490 Hv with increasing heat treatment temperature. That in vacuum environment deceases from 550 Hv to 530 Hv. The boundary between particles became vague as heat treatment temperature increases. Oxygen distribution of tantalum coating layer is minute after heat treatment in vacuum environment than Ar gas environment.
        4,000원
        6.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to examine the influence that factors for a successful venture have on business performance. To fulfill this goal, factors for a successful venture are presupposed as the four elements of business creator, technological innovation, type of strategy, and organization, while business performance is set as subordinate variable, with a view to creating a model and establishing a hypothesis for a positive analysis. Data collection for the positive analysis was conducted using a questionnaire, and as for sampling, of the companies located in Seoul and greater metropolitan region and registered with Small and Medium Business Administration as of late December 2012, 98 companies have been selected for the final data. And I have come up with the two following results. First, factors for venture success have all proven to exercise statistically significant influence on business performance. Second, of all factors for venture success, business creator and technological innovation exercise huge influence on business performance, as compared to the other factors. From these two conclusions, it is understood that to upgrade business performance of a venture, business creator and technological innovation should be given priority over the other factors.
        4,000원
        7.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study attempted to manufacture a Cu-Ga coating layer via the cold spray process and to investigate the applicability of the layer as a sputtering target material. In addition, changes made to the microstructure and prop- erties of the layer due to annealing heat treatment were evaluated, compared, and analyzed. The results showed that coating layers with a thickness of 520 mm could be manufactured via the cold spray process under optimal conditions. With the Cu-Ga coating layer, the α-Cu and Cu3Ga were found to exist inside the layer regardless of annealing heat treatment. The microstructure that was minute and inhomogeneous prior to thermal treatment changed to homogeneous and dense with a more clear division of phases. A sputtering test was actually conducted using the sputtering target Cu- Ga coating layer (~2 mm thickness) that was additionally manufactured via the cold-spray coating process. Consequently, this test result confirmed that the cold sprayed Cu-Ga coating layer may be applied as a sputtering target material.
        4,000원
        8.
        2013.05 구독 인증기관·개인회원 무료
        This study was carried out to investigate comparision anaylsis of metabolites in mandarin leave inoculated by Elsinoe fawcetii. For the analysis of metabolites, we performed using by UPLC-MS spectrometry in gradient eluent condition by acetonitrile and water. Flow rate was 0.4ml/min. Instruments conditions were followed by detection ion mode(positive ion), scan range(MS:m/z100-1000), spray voltage (4kV) ,capillary voltage(35v), capillary temp(300℃). Several flavones were detected in inoculated pathogen compared to control.
        9.
        2013.05 구독 인증기관·개인회원 무료
        Three edible mushrooms; "Gumbit"(Pleurotus cornucopiae var. citrinopileatus) and Noeul"(Pleurotus salmoneostramineus) and Tricholoma spectabilis which are widely distributed in China, Japan and Korea. For the study of anti-aging activities, we were performed on adriamycin-induced cellular senescence model. Human dermal fibroblasts(HDFs) and human umbilical endothelial cells(HUVECs) treated with adriamycin for inducing aging were used for cytotoxicity and senescence-associated beta-galactosidase(SA-β-gal) activity assay.
        10.
        2013.05 구독 인증기관·개인회원 무료
        Cordyceps militar is (Clavicipitales) is an edible mushroom which is widely distributed in China, Japan and Korea. Various phytochemical constituents, cordycepin, homocitrully laminoadenosine and sterols have been reported from this source and a wide range of biological activities, including antimicrobial, macrophage activation, anticancer, immune modulatory effects were studied. In a continuing search for bioactive constituents from Korean mushrooms, we performed a phytochemical investigation of the MeOH extract from the fruiting bodies of C. militaris. By repeated column chromatographic separation of the extract, fourteen compounds, were isolated. The identification and structural elucidation of the compound was based on NMR spectral data. anti-aging activities were performed on adriamycin-induced cellular senescence model. Human dermal fibroblasts(HDFs) and human umbilical endothelial cells(HUVECs) treated with adriamycin for inducing aging were used for cytotoxicity and senescence-associated beta-galactosidase(SA-β-gal) activity assay.
        11.
        2012.06 구독 인증기관·개인회원 무료
        This study was carried out to investigate anticancer activities fruiting body extracts and fractions of Cordyceps militaris. Fruiting body of this mushroom was extracted using by 80% MeOH. Fractionations of these extracts were performed by n-hexane, methylene chloride, ethyl acetate, n-BuOH. AGS(human gastric cancer line) was cultured in media conditions (10% FBS, 1% Penicillin-Streptomycin in RPMI). Anticancer activities of each fractions of Cordyceps militaris were examined by using MTT, Cell titer Glo.
        12.
        2011.05 구독 인증기관·개인회원 무료
        This study was carried out to investigate neuronal protective activity of fruiting body of Hericium erinaceum. In order to search the effective active compound against amyloid beta peptide-induced oxidative stress on neuronal cells, rat pheochromocytoma cells (PC12), Extracts of Hericium erinaceum were screened and evaluated using both the 2’,7’-dichlorofluorescin diacetate assay (DCF-DA), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. According to above assays, Solvent partitions of extracts were selected for further purification and isolation of anti-Alzheimer’s disease compound as it exerted the highest protective effects against hydrogen peroxide (H2O2)-induced oxidative stress.
        13.
        2010.06 KCI 등재 구독 인증기관·개인회원 무료
        This study was carried out to investigate characteristic pattern of fruiting body of Ganoderma lucidum and their antioxidant activity. Mycelia of all strains were firstly inoculated into potato dextrose agar(PDA) and then transfered to a media of saw dust which contained 20% rice bran. These mycelia of saw dust were then inoculated into oak tree in polyethylene bags which has been sterilized for 8h at 120℃. The polyethylene bags were sent to a growth room for growth of fruit bodies. Antioxidant activities of each fruiting body were examined by using DPPH(α,α-diphenyl-β-picrylhydrazyl).
        14.
        2000.05 구독 인증기관 무료, 개인회원 유료
        The recycling cell formation problem means that disposal products are classified into recycling part families using group technology in their end of life phase. Disposal products have the uncertainties of product status by usage influences. Recycling cells are formed considering design, process and usage attributes. In this paper, a novel approach to the design of cellular recycling system is proposed, which deals with the recycling cell formation and assignment of identical products concurrently. Fuzzy clustering algorithm and Fuzzy-ART neural network are applied to describe the states of disposal product with the membership functions and to make recycling cell formation. This approach leads to recycling and reuse of the materials, components, and subassemblies and can evaluate the value at each cell of disposal products. Application examples are illustrated by disposal refrigerators, compared fuzzy clustering with Fuzzy-ART neural network performance in cell formation.
        4,500원