• Korean Journal of Medicinal Crop Science
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• v.4 no.1
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• pp.52-57
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• 1996

This study was carried out to compare isozyme band pattern, growth characteristics and tuber yield of Dioscorea batatas to get basic information for varietal classification. It could be identify clearly by protein and esterase band pattern of leaf, petiole and stem tissue in three cultivar but with peroxidase band it was difficult to identify because of similar pattern in leaf and petiole tissue. Three cultivars has different leaf shape as Dan-ma and Jang-ma were lanceolate, Sukunea was long-heart shape in upper part of plants. In phyllotaxis, Dan-ma and Jang-ma shows alternate and opposite but Suwon 2 shows opposite in upper parts of stem. Root length shows significant difference from 9.7cm to 51cm respectively as 30cm, 51cm and 9.7cm in Dan-ma, Jang-ma and Sukunea. Tuber yield of three cultivars were 27.5M/T in Dan-ma, 22.8M/T in Jang-ma and 22.8M/T/ha in Sukunea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.746-753
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• 2017

Radar Cross Section (RCS) is a factor directly related to survivability, and a design to reduce the presence of this factor is needed. The upper structure, guns, radar and so on are related to warship RCS, but radar RCS reduction is difficult because of complex shapes involved. In this paper, an enclosed mast, which is one modern method for reducing radar RCS, and the characteristics of an applied Frequency Selected Surface (FSS) are analyzed. The RCS reduction ability of an enclosed mast has been confirmed by comparing RCS analysis results for a general radar with that of an enclosed mast for available frequency according to FSS shape. The characteristics of the enclosed mast have also been studied by analyzing the elevation angle and slope of the mast. General radar RCS was high because of its complex shape, but low RCS was shown for the enclosed mast model, which had a simpler shape.

• Journal of Ginseng Culture
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• v.4
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• pp.59-102
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• 2022

Since there were only few countries that could find wild ginseng grown in nature, the culture of digging wild ginseng was only developed in a small number of countries. In a time when the orthodox head-Simmemani has disappeared, the tangible and intangible culture of Simmemani (wild ginseng digger) is disappearing more and more with the passage of time. So far, the conducted research on wild ginseng diggers was very partial and simplistic as follows: ① Research on the argot of Simmemani, ② Research on the customs of Simmemani, ③ Research on the change of customs of Simmemani, ④ Additional records through interview with Simmemani. Accordingly, no comprehensive study on the Simmemani culture has been done yet. This study supplements the historical materials that were not reflected in previous studies, and discuss on diverse subjects including the definition and classification of wild ginseng, the distribution of wild ginseng and Simmemani, interpretation of wild ginseng digging from a legal and social point of view, the organization responsible for the digging, determination of the date of entering the mountain, preparations, taboos, departure and entry into a mountain, religious events, psalmbook, dream interpretation, search and discovery of wild ginseng, digging, profit sharing, the amount of harvested wild ginseng, and the price of wild ginseng. In addition, Korean wild ginseng digging culture was comprehensively studied by attaching the photos and illustrations of historical documents with the psalmbook of the head-Simmemani.

• Korean Journal of Social Welfare Studies
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• v.44 no.2
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• pp.231-264
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• 2013

The purpose of this study is to find out how local residents using social welfare services in permanent rental apartment areas experience stigma, and how they perceive it. Data collection was carried out for 10 months from May 2012 to February 2013. Interviews were conducted with 13 users who are using or have the experience of using services in social welfare centers, and 12 hands-on workers of the institutions; the results were then analyzed using the modified grounded theory. The results of analysis are as follows. First, a considerable number of people living in permanent rental apartment areas experience stigma while experiencing impoverishment; and they also feel stigma in the formularization process to become recipients. Second, users experience stigma in the process of using social welfare center services located in permanent rental apartment areas after becoming recipients as well. Third, in cases where permanent rental apartment areas are located in the immediate neighborhood of general residence areas, residents living inside and outside the areas were found to give stigma to the residents of permanent rental apartment areas. This study has significance in that it provides an in-depth clarification of the reality of stigma experienced by users of social welfare center services in permanent rental apartment areas through qualitative research

• School Mathematics
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• v.9 no.4
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• pp.507-521
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• 2007

The purpose of this study was to investigate the effects of memory retention of mathematical concepts in multiplication in the inquiry-based pantomime instructions. Three months later after the pre-test, a comparison was made between traditional class (TC) and class with the inquiry-based pantomime (IP) approach in terms of students retention of mathematical understandings. Results of the study indicated that the If instructions promoted effective long-term retention of knowledge. We concluded that instructional strategies that promoted active engagement in learning using life examples and drawings produced effective long-term retention of knowledge.

• Journal of the Korean Magnetics Society
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• v.20 no.5
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• pp.178-181
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• 2010

Search coil magnetometer has been used for detection of ac magnetic field with high sensitivity. To reduce demagnetizing factor of core and increase S/N ratio of search coil magnetometer, the core was divided by two parts and coil was wound on each cores. Two coils were connected serially and put into amplifier as differential mode. Constructed 120 mm length search coil magnetometer shows linearity of 0.03%, sensitivity of 9.3 mV/nT, and resolution of 20 pT at 1 Hz.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.249-250
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• 2010

This study analyzes the basic characteristics of the concrete using recycled coarse aggregates produced by using a rotary crusher and compares it to that of using a cone crusher. As a result, the recycled aggregate produced by using the rotary crusher represents more excellent results in fluidity and compressive strength according to the increase in the replacement rate of recycled aggregates than that of using the cone crusher. It can be analyzed that it was due to the fact that the particle shape of the recycled aggregate produced by using the rotary crusher showed round figures relatively and that leaded to reduce friction force and remove lots of grouted mortar caused by its wearing.

• Journal of the Korean Magnetics Society
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• v.12 no.4
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• pp.149-153
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• 2002

Flux-gate magnetometer has been still used for low field magnetic field measurement with portability, low power consumption, and high reliability. In many applications, flux-gate magnetometer measures not absolute values but changes of the earth magnetic field. For the eia magnetic field change measurements, we have constructed a high sensitive 3-axis flux-gate magnetometer of which measuring ranges is ${\pm}$1000 nT and noise level is 5pT/√㎐ at 1 ㎐. Using this magnetometer, we can compensate the earth magnetic field of ${\pm}$50,000 nT with successive approximation methods using microcomputer. After earth magnetic field compensation, we could measure earth magnetic field changes with ${\pm}$100 nT measuring ranges.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.63-70
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• 2012

Magnetite in the use of magnetic fluid seal was synthesized by coprecipitation method. Mean particle size of magnetite was measured about 12 nm by using dynamic light scattering(DLS). As a result of XRD test, along with the $NH_4OH$ concentration was increased, the crystallinity of magnetite was increased. The zeta potential of dispersed ferrofluid in water was measured in the range from -49.3 mV to -26.2 mV by DLS. The shape of magnetite particle was sphere form, and the spiking effect of aqueous and oily ferrofulid was confirmed.

• Polymer(Korea)
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• v.28 no.2
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• pp.170-176
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• 2004

The effect of reaction conditions on the size and size distribution of superparamagnetic iron oxide coated with siloxane was big investigated by using dynamic light scattering. The hydrogen bond between the hydroxyl groups on tile surface of the magnetite and silanol was confirmed by FT-IR. The size of nanoparticles increased with the reaction temperature, but decreased with monomer contents and agitation speeds. There was not a big difference in size of nanoparticles, prepared by different reaction conditions, but its distribution was in the range of 14∼41nm. All samples exhibited the superparamagnetic nature. The magnetic susceptibility of the nanoparticles increased with the reaction temperature while it decreased with the monomer content and agitation speed.