• Journal of Welding and Joining
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• v.31 no.4
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• pp.54-61
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• 2013

This paper reports mild steel(SPHC) and stainless steel(STS304) sheets commonly used for railroad cars or commercial vehicles such as in the automobile and shipbuilding industries. The sheets are used in these applications, which are mainly fabricated using the shielded metal arc welding(SMAW) of dissimilar materials. It also reports an interesting application of Laser Induced Breakdown Spectroscopy(LIBS) in order to determine the elemental composition diffusion of SPHC and STS304. Arc blow produced by magnetic force during the electric arc welding prevents the formation from a sound weldment. In particular, the mechanical properties of the joint are influenced by not only by geometrical and mechanical factors but also the welding conditions for the arc welded joint. Therefore, the mechanical properties and performance are evaluated by performing a physicochemical component analysis. And they increase in accordance with content of elements and microstructure in mild steel. As results, appropriate range for magnetic fields could be achieved. Therefore, the effect of magnetic force in a butt weld of mild steel plates was investigated by comparing to the measured data.

• Journal of Powder Materials
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• v.10 no.4
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• pp.235-240
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• 2003

The $Al/Al_2O_3$ composites fabricated by powder in sheath rolling method were cold-rolled by 50% reduction and annealed for 1.8 ks at various temperatures ranging from 200 to 50$0^{\circ}C$, for improvement of the mechanical properties. The mechanical properties and texture of the composites after rolling and annealing were investigated. The tensile strength of the composites increased significantly due to work hardening after cold rolling, however it decreased due to restoration after annealing. The strength of the composites was improved by thermo mechanical treatment. On the other hand, the texture evolution with annealing temperatures wa,i different between the unreinforced material and the composites. The unreinforced material showed a deformation (rolling) texture of which main component is ｛112｝<111> at annealing temperatures up to 30$0^{\circ}C$. However, the composites have already exhibited a recrystallization texture of which main component is ｛001｝<100> after annealing at 20$0^{\circ}C$. This proves that the critical temperature for recrystailization is lower in the composites than in the unreinforced ones.

• Journal of Powder Materials
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• v.11 no.3
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• pp.259-264
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• 2004

Aluminum based metal matrix composite reinforced with SiC particles was fabricated by the powder-in sheath rolling method. A stainless steel tube with outer diameter of 12 mm and wall thickness of 1mm was used as a sheath. Mixture of aluminum powder and SiC particles of which volume content was varied from 5 to 20vol.% was filled in the tube by tap filling and then rolled to 75% reduction at ambient temperature. The rolled specimen was sintered at 56$0^{\circ}C$ for 0.5hr. The tensile strength of the (SiC)$_{p}$/Al composite increased with the volume content of SiC particles, and at 20vol.% it reached a maximum of 100㎫ which is 1.6 times higher than unreinforced material. The elongation decreased with the volume content of $Al_{2}$O$_{3}$ particles. The mechanical properties of the (SiC)$_{p}$/Al composite fabricated by the powder-in sheath rolling is compared with that of (Al$_{2}$O$_{3}$)$_{p}$/Al composite by the same process.ess.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.308-308
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• 2017

국내 하천에 설치된 횡단구조물은 2009년을 기준으로 약 20,753개로 알려져 있으며 수위 유지, 하상고 유지 등의 목적을 가지고 설치된다. 그러나 낙차를 가진 빠른 유속의 흐름을 형성시켜, 하류 하상에서 국소 세굴을 발생시킨다. 이를 방지하기 위해 횡단구조물 하류에 굴요성 구조(flexible structure)인 돌망태, 블록공, 사석 등으로 이루어진 바닥보호공(bed protection)이 설치되나 유실, 침하 등의 문제가 빈번히 발생되고 있어, 문제를 해결하기 위한 연구가 필요하다. 본 연구는 이러한 피복 대책에서 일어날 수 있는 파괴 기구인 전단파괴, 흡출 파괴, 경계 파괴, 하상 형태 변화에 따른 하부 침식 중 흡출 파괴(winnowing failure)를 유발하는 흐름을 검토하기 위한 수치모의를 수행하였다. 이때 흡출 파괴는 바닥보호공의 공극으로 미세한 하상 재료가 난류와 침투류의 작용에 의해 침식되어 바닥보호공이 침하되는 것을 말한다. 수치모의는 전산유체동역학(Computational Fluid Dynamics, CFD) 모형인 FLOW-3D 모형을 이용하였으며, 난류 모형으로 LES 모형을 적용하고 조밀한 격자를 부여하여 바닥보호공의 공극에서 발생되는 비교적 작은 척도의 와(vortex)를 해상할 수 있도록 하였다. 수치모의에 적용된 횡단구조물은 보, 물받이공, 바닥보호공으로 구성하였으며 특히, 바닥보호공의 형상은 구체(sphere)로 가정하여 다층으로 배치하였다. 바닥보호공의 공극 또는 구체 사이에서 발생되는 유속, 압력 등의 흐름특성을 분석한 결과, 바닥보호공 두께가 두꺼울수록 흡출 파괴에 대해 안정적인 것으로 나타났다. 이는 바닥보호공 설계를 위한 기초자료로 활용될 수 있으며, 향후 입자영상유속계(Particle Image Velocimeter, PIV)와 같이 공극에서 흐름을 측정할 수 있는 방법과 병행한 연구를 수행할 수 있을 것이다.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.35-45
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• 2018

Image data collected by an airborne hyperspectral camera system have a great usability in coastal line mapping, detection of facilities composed of specific materials, detailed land use analysis, change monitoring and so forh in a complex coastal area because the system provides almost complete spectral and spatial information for each image pixel of tens to hundreds of spectral bands. A few approaches after classifying by a few approaches based on SAM(Spectral Angle Mapper) supervised classification were applied for extracting optimal land cover information from hyperspectral images acquired by CASI-1500 airborne hyperspectral camera on the object of a coastal area which includes both land and sea water areas. We applied three different approaches, that is to say firstly the classification approach of combined land and sea areas, secondly the reclassification approach after decompostion of land and sea areas from classification result of combined land and sea areas, and thirdly the land area-only classification approach using atmospheric correction images and compared classification results and accuracies. Land cover classification was conducted respectively by selecting not only four band images with the same wavelength range as IKONOS, QuickBird, KOMPSAT and GeoEye satelllite images but also eight band images with the same wavelength range as WorldView-2 from 48 band hyperspectral images and then compared with the classification result conducted with all of 48 band images. As a result, the reclassification approach after decompostion of land and sea areas from classification result of combined land and sea areas is more effective than classification approach of combined land and sea areas. It is showed the bigger the number of bands, the higher accuracy and reliability in the reclassification approach referred above. The results of higher spectral resolution showed asphalt or concrete roads was able to be classified more accurately.

• Journal of Korean Society of Forest Science
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• v.47 no.1
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• pp.44-51
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• 1980

In order to find out the suitable methods that can omit the earth healing and increase the survival through improving the seedling-healing and transportable methods. Several trials with plastic vinyl have been done and its results are as follows: 1. Though P. rigitaeda seedling have been stored in the black and white vinyl sack for 35 days in the storehouse. This seedling have survived with very high percentage as Table 1. This means that the earth healing work at the nursery or planting area can be omitted if seedling sould be stored in the storehouse by using the vinyl sack. The possibilities of long-period storage in the black and white vinyl sack seem to be come from the reasons that air humidity in the sack is nearly 100% and its air temperature is only around $15^{\circ}C$ with very little difference between day and night time. This sack also can be utilized in place of the planting sack, and though this sack with seedling have been laid under direct sunshine for 1 to 2 days. Any difference between the sack stored in the storehouse has not been observed on the survival specially Table 2. 2. When the bundled seedling have been covered with the black and white vinyl instead of earth healing, even if these seedling have been laid for 18 days under the vinyl. This seedling show us high survival as Table 3. High humidity with nearly 95%, very little difference of air temperature between day and night time under the vinyl and not so big difference between out-and inside temperature could be reasons of high survival to be considered. So through covering by the black and white vinyl. The labour power for earth healing works can be saved also. 3. In order to protect the healed seedling from the direct sunshine and the eva-transpiration. Black vinyl net and reed mat could be effective for this purpose. Because vinyl net could intercept around one to third, reed mat two to third of total solar energy and also suppress more than 50% of total water loss by the transpiration.

• Journal of the Korea Concrete Institute
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• v.20 no.4
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• pp.423-430
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• 2008

VES-LMC (very-early strength latex-modified concrete) has been widely used as repair material for bridge deck overlay or rehabilitation, because the overlaid or repaired could be opened to the traffic after 3 hours of curing. Although the field performance of VES-LMC generally indicates that it has an excellent bonding to the substrate and shows a long term performance, little quantitative data or research results have been presented in the literature on structural studies. The purpose of this study was to investigate the flexural behavior, interfacial performance, crack propagation, and strengthen effect of RC beam overlaid or repaired by VES-LMC through the 4-point flexural loading test. Two different types of RC beam were fabricated for repair and rehabilitation types. The test result showed that the strengthen effect, in term of flexural stiffness, increases as the depth of repair or overlay increases. More than 40% of stiffness was improved when the depth of repair was up to steel position. However, there was a little difference between 80 mm and 120 mm repaired beam. This means the repair depth must be considered. The interfacial behavior data showed that the repaired or overlaid beams had a little relative displacement. This means that two materials behave comparatively acting together. However, there were two specimens which had large displacement at the interface, because of poor bond strength. This suggested that interface treatment is one of the most important jobs in composite beams.

• Journal of the Korea Institute of Building Construction
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• v.17 no.2
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• pp.149-155
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• 2017

In this research, the surface covered curing method using the double-layered bubble sheet was evaluated. This double-layered bubble sheet has outstanding insulating performance with its low heat conductivity and high economic feasibility with its high durability. However, in the case of wall-typed building construction, the area of exposed rebar is curious on curing performance with the double-layered bubble sheet in spite of the double-layered bubble sheet showed favorable performance for slab. Therefore, in this research, regarding the actually constructed wall-typed apartment building, the most efficient curing method was suggested based on the evaluation of curing performance depending on temperature distribution depending on various location of covered or exposed rebar. As a result, the D method was determined as the most efficient curing method without any concern of early-age frost damage. However, by considering easiness of construction, the B method of covering the pieced double-layered bubble sheet on gap between rebars can be another option of desired result.

• The Research Journal of the Costume Culture
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• v.8 no.6
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• pp.853-863
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• 2000

This study is planned to present the future direction of the study of Korean clothes through the realistic recognition of the changes of studying issues of each area of the related clothes. For this purpose, the writer of this thesis have collected, classified and analyzed those various kinds of papers and theses published in the professional magazines of clothes such as Journal of Korean Home Economics, Journal of the Korean Society of Clothing and Textiles, Journal of the Korean Society of Costume, The Research Journal of the Costume Culture so that I might examine and study the main trend of the related study. The result of the study is as follows. 1. Since the first publication of Journal of Korean Home Economics in 1959 and Journal of the Korea Society of Clothing and Textiles, and Journal of the Korean Society of Costume, the study of clothes has been gradually increased. Furthermore, since 1990 the issuing times of various kinds of Journals have been continuously increased with the foundation of The Research Journal of the Costume Culture and Journal of Fashion Business. 2. Theses and papers published in the four greatest Journals of Korean Clothing and Textiles have been studies for the detailed classification and analysis of the data. According to the study, It is found that the theses in Journal of the Korea Society of Clothing and Textiles have actively studied textiles as they had studied before 1990s and those in Journal of the Korean Society of Costume have studied history of costumes and those in The Research Journal of the Costume Culture have studied the composition and science of clothes. 3. The order of studying subjects was 1) Design and Aesthetics, 2) Fashion Merchandising 3) Textiles, 4) Clothing Construction, 5) History of Costumes, 6) Costume Culture, 7) Socio-Psychology of clothing, 8) Others. Considering the above mentioned result of the study, most of the main fields of the clothing and textiles study have been studied continuously in balance since 1990 unlike the past although the past studies had been performed largely in some main fields only. And it was found that fields of clothing styles and clothing goods have been studied most actively since 1990s. 4. The studying field of Design and Aesthetics has showed to have the trend to be studied very actively since 1990s, which has utilized various relevant data with scholastic approach to psychology and aesthetics. Regarding Fashion Merchandising, the study of consumers decision process has been performed most actively. And theses on the international trades have been published considerably more than ever before, which resulted in gradual increase in gradual increase in the study of the fields related with global marketing, internet marketing, textile products exports, and overseas brands, etc. Regarding Textiles, the field of clothing sanitation and management has been studied more actively than that of clothing materials. In case of clothing construction, the study of physical styles and pattern making has been more active than the other related fields. Fields of socio-psychology of clothing and history costume have been a little reduced. Field of costume culture has been firmly rooted as an independent subject to be studied in the clothing related study. And study of the clothes has shown various trends of studies of ethnic & folk clothes, religious and ceremonial garments, linguistic & favorite approach to clothes and academic analysis of the data.

• Applied Biological Chemistry
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• v.20 no.3
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• pp.296-299
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• 1977

The blue, green, and red colored polyethylene film was used as a covering material for house grown pepper production to compare with the white film. Plant height was the tallest in red PE house(78.8 cm) followed by white, blue, and green PE house. The leaf weight was 0.40g in white PE house and 0.39g in red PE house which was higher than the weight in blue and green PE house. Fruiting percentage was 48.0% and 46.1% in white and red PE house, respectively, however no fruit was set in blue and green PE house. The fruit weight was 3.32g and 2.81g, in red and white PE house, respectively. The K, Ca, Mg, and Fe content in the leaf was the lowest in plants grown in white PE house. The content of K, Ca, Mg, and Fe was the highest in plants grown in green PE house.