• Research in Plant Disease
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• v.23 no.1
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• pp.82-87
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• 2017

During 2012 to 2014, a survey for the presence of viral diseases in yam plants was carried out in a field of the Institute for Bioresources Research in Gyeongsangbuk-do, Korea. A total of 88 leaf samples were collected and tested by reverse transcription polymerase chain reaction using specific primer sets. Eighty-one samples were positive for Broad bean wilt virus 2 (BBWV2), Chinese yam necrotic mosaic virus (ChYNMV), Cucumber mosaic virus (CMV), Japanese yam mosaic virus (JYMV), and Yam mild mosaic virus (YMMV), whereas Yam mosaic virus (YMV) was not detected. Additionally, seven samples were negative for all viruses. Several samples exhibited mixed (double and triple) infections. Three viruses (CMV, JYMV, and YMMV) were detected for the first time in yam plants in Korea. A BLAST search showed that three viruses shared nucleotide identities with CMV-Ca (98%), JYMV-O2 (91%), and YMMV-TG_NH_1 (86%). Thus, our findings confirmed that yam plants cultivated in Korea were infected with multiple viruses with three of these viruses reported for the first time in Korea.

• Archives of Plastic Surgery
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• v.36 no.1
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• pp.66-74
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• 2009

Purpose: The importance of the deformities in alar - columellar complex has been underestimated in Asian ethnic groups for the last decades. Fortunately, with increasing familiarity of the open rhinoplasty techniques, the anatomic details of the nasal tip have been pointed up. Definitely, having an interest and demand for improving the sub - normal relationship between the alar rim and columella are indebted for such growing of knowledge about nasal tip anatomy. However, it is true that any single procedure is not settled as versatile and fully confident modality to correct the retracted notching of the alar rim. With this article, I should like to propose another useful option for treating retracted ala. Methods: The author has tried to correct alar rim retraction by means of: (1) Triangular onlay septal cartilage graft on the lower lateral cartilage with the medial end fixed to the anterior surface of the lateral crus(Alar extension graft), (2) Inserting lateral end of the alar extension graft to the vestibular skin pocket in the form of a finger - in - groove, (3) using the vestibular skin in the form of an advancement flap, and (4) using the soft shield graft to prevent possible visible step - off of the alar margin. Results: The author applied an alar extension graft to 16 patients in order to correct a retracted ala for the last 27 months (August, 2003 - October, 2005). The distances from alar rim to long axis of nostril were improved to be within 2 mm in all of the cases, and also the shape of the alar rim changed to a round form. Nostril asymmetry (6%) in one case, temporary palpable step - off (18%) in three cases, temporary visible step - off (6%) in one case, and temporary paresthesia of the tip (25%) in four cases were observed. Conclusion: The alar extension graft is simple and efficacious. It does not need donor sites other than the operative field, and its results are predictable. In particular, since it may give structural intensity to a weak lower lateral cartilage, it may be preferentially used for the correction of a retracted ala that arises from hypoplastic lower lateral cartilage. Moreover intensified lower lateral cartilage also improves the esthetic shape of lobule.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.107-118
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• 2002

This paper deals with an automated computer-aided process planning and die design system by which designer can determine operation sequences even if they have a little experience in process planning and die design of quasi-axisymmetric cold forging product by cold former working. The approach to the system is based on knowledge-based rules and a process knowledge base consisting of design rules is built. Knowledge for the system is formulated from plasticity theories, empirical results and the empirical knowledge of field experts. Programs for the system have been written in AutoLISP for the AutoCAD using a personal computer. An attempt is made to link programs incorporating a number of expert design rules with the process variables obtained by commercial FEM softwares, DEFORM and ANSYS, to form a useful package. The system is composed of three main modules and five sub-modules. The process planning and die design module considers several factors, such as the complexities of preform geometry, punch and die profiles, specifications of available cold farmer, and the availability of standard parts. As the system using 2D geometry recognition is integrated with the technology of process planning, die design, and CAE analysis, the standardization of die parts for wheel bolt requiring cold forging process is possible. The developed system makes it possible to design and manufacture quasi-axisymmetric cold forging product more efficiently.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.607-612
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• 2017

Recently, additive manufacturing (AM) technology, also known as 3D printing technology, has attracted attention as an innovative production method to fabricate functional components having complex shapes with saving materials. In particular, a fabrication of poly lactic acid (PLA) parts through a fused deposition modeling (FDM) technique has attracted much attention in the medical field. In this paper, an experimental study on the identification of dominant process parameters influencing mechanical properties of PLA parts fabricated by the FDM process is conducted, and their optimal values for maximizing the mechanical properties are obtained. Three process parameters are considered in this research, namely, layer thickness, a part orientation and in-fill. It is known that thin layer thickness, part orientation diagonal to the tension direction, and full in-fill are optimal conditions to maximize the mechanical properties.

• Progress in Superconductivity
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• v.4 no.1
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• pp.86-89
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• 2002

In this paper, the design of a IMVA single-phase high temperature superconducting(HTS) power transformer with BSCCO-2223 HTS tapes is presented. The rated voltages of each sides of the transformer are 22.9 ㎸ and 6.6 ㎸, respectively The winding of 1MVA HTS transformer is consisted of double pancake type HTS windings, which have advantages of insulation and distribution of high voltage, and are cooled by subcooled liquid nitrogen of 65K. Four HTS tapes were wound in parallel for the windings of low voltage side and the four parallel conductors are transposed. The design of 1MVA HTS transformer, a shell type core made of laminated silicon steel plate is chosen, and the core is separated with the windings by a cryostat with a room temperature bore. The cryostat made of non-magnetic and non-conducting material and a liquid nitrogen sub-cooling system is designed in order to maintain the coolant's temperature of 65K. For electromagnetic analysis of 1MVA HTS transformer, a finite element method of an axis of symmetry is used. The maximum perpendicular component of magnetic flux density of pancake windings is about 0.15T. And through analyzing the magnetic field distribution, an optimal winding arrangement of 1MVA HTS transformer is obtained.

• Journal of Welding and Joining
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• v.28 no.1
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• pp.66-71
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• 2010

With large specific strength and outstanding corrosion resistance and erosion resistance in sea water, titanium and titanium alloy are widely used in heat exchanger production. In particular, pure titanium demonstrates outstanding molding performance and may be considered optimal for production of heat exchanger. Since titanium is very vulnerable to oxidation and embrittlement during welding, processes with less heat input are widely used, and laser welding is widely applied by considering production performance and shield etc in atmosphere. So far, 1st report and 2nd report compared and analyzed embrittlement degrees by bead colors of weldment through oxygen and nitrogen quantitative analysis and hardness measurement, and evaluated welding performance and mechanical properties of butt welding. This study evaluated field applicability of lap welding to heat exchange plate of LPG re-liquefaction device for ships through tensile stress test, hardness test and internal pressure test etc after deducing optimal weding condition and applying to actual heat exchange plate. In bead overlap area, the experiment produced sound welds with no porosity or defect by increasing and decreasing laser power, and tensile-shear test results indicated virtually the same tension and yield strength as base metal. As a result of measuring hardness at lateral cross section and bead overlap zone of actual heat exchanger welds, hardness difference within 20Hv was produced at base metal, HAZ and weldment, and as a result of pneumatic and hydraulic pressure test, no leakage occurred.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.466-468
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• 2012

Amorphous InGaZnO (${\alpha}$-IGZO) thin-film transistors (TFTs) are are very promising due to their potential use in thin film electronics and display drivers [1]. However, the stability of AOS-TFTs under the various stresses has been issued for the practical AOSs applications [2]. Up to now, many researchers have studied to understand the sub-gap density of states (DOS) as the root cause of instability [3]. Nomura et al. reported that these deep defects are located in the surface layer of the ${\alpha}$-IGZO channel [4]. Also, Kim et al. reported that the interfacial traps can be affected by different RF-power during RF magnetron sputtering process [5]. It is well known that these trap states can influence on the performances and stabilities of ${\alpha}$-IGZO TFTs. Nevertheless, it has not been reported how these defect states are created during conventional RF magnetron sputtering. In general, during conventional RF magnetron sputtering process, negative oxygen ions (NOI) can be generated by electron attachment in oxygen atom near target surface and accelerated up to few hundreds eV by self-bias of RF magnetron sputter; the high energy bombardment of NOIs generates bulk defects in oxide thin films [6-10] and can change the defect states of ${\alpha}$-IGZO thin film. In this paper, we have confirmed that the NOIs accelerated by the self-bias were one of the dominant causes of instability in ${\alpha}$-IGZO TFTs when the channel layer was deposited by conventional RF magnetron sputtering system. Finally, we will introduce our novel technology named as Magnetic Field Shielded Sputtering (MFSS) process [9-10] to eliminate the NOI bombardment effects and present how much to be improved the instability of ${\alpha}$-IGZO TFTs by this new deposition method.

• Korean Journal of Materials Research
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• v.10 no.8
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• pp.558-563
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• 2000

$Y_2SiO_5:Ce$ phosphor was coated with $In_2O_3$, $Al_2O_3$ and $SiO_2$ and then their cathodoluminance(CL)proper-ties required in field emission display were investigated. It was found that luminance efficiency and aging p개perty of $Y_2SiO_5:Ce$ phosphor was decreased with $In_2O_3$coating. For the case of coating, the luminance intensity was in blue phosphor was dramatically increased with $SiO_2$ coating. And also the aging property of $Y_2SiO_5:Ce$ Phosphor coated with $SiO_2$ was significantly improved compared to non-coated sample.

• Analytical Science and Technology
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• v.8 no.4
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• pp.759-770
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• 1995

By extensive studies with the quantitative status of the mineral constituents of thousands of water samples, it was found that almost in all natural waters irrespective of the surface or sub-surface sources, minimum 99.5% of the total amount of the cationic constituents are generally the contributions of 3 commonly present parameters viz. Ca, Mg and Na and that of the anionic species are same and contributed by $HCO_3$, Cl and $SO_4$ only. In the field of water works, all these major mineral substances are conventionally measured as their individual ions. But till now, no reliable and generalised methods or rules have been developed for the determination of the exact kinds of the individual salt components and their amounts from these ionic constituents normally present in water. As salt content, only the TDS (Total Dissolved Solids) parameter is frequently measured by evaporation of the water sample. But TDS can tell nothing about the kinds and amounts of the individual salts present in it. Considering the analytical importance of the estimation of the mineral substances as their individual salts, some generalised mathematical models have been developed by this research which are based on the 'hypothetical order of chemical combinations' as may occur among the ionic constituents. With the help of these models, one can easily assume the most probable salts with approximate quantities derived from the ionic constituents. In addition, approximate amount of Na content can also be estimated mathematically with simultaneous verification of the correctness of the water analysis results. The models are stated in this paper with practical illustrations and descriptions of the method of applications.

• Korean Journal of Community Nutrition
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• v.22 no.2
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• pp.103-114
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• 2017

Objectives: This study aims to investigate the married female immigrants' experience on Korean dietary life adaptation, especially identifying the symbolic meaning and nature of experiences. Methods: This study was conducted with six married female immigrants through an analysis of the qualitative materials which consisted of in-depth interviews, field notes and materials. Data was analyzed using Giorgi's phenomenological research methods. Results: The results were deduced as 116 significant statements, 17 formulated meanings (sub-theme), and 6 theme clusters. Six theme clusters comprised of lack of preliminary knowledge and information, conflict and support in relationships, Korean food culture which is different from homeland, adaptation attitudes of Korean food culture according to situation, sharing of homeland food culture, and practical difficulty and expectative service. The participants started Korean life in the dark about Korea and Korean food culture, so they were subjected to trial and error. The conflict between Korean mother-in-law and foreign daughter-in-law came from lack of consideration of daughter-in-law's cultural background. Some participants were hurt because of misunderstanding and nitpicking. They were learning about cooking method, ingredient, seasoning, table setting and manner. Some participants integrated Korean food culture and their homeland food culture. Some of them assimilated with Korean food culture. One of them maintained homeland food culture. The participants who adapted Korean food culture well could share homeland food amicably. They sometimes didn't apply the services which were offered by the government, because the services did not fit their needs. Some of them didn't know the usage route of the services or information. They had resistance about home teaching and it showed that outreach service was not always effective. Conclusions: This study suggested that it is necessary to develop a practical support plan which covers married female immigrants' real needs and system improvement measures.