• Journal of Korean Society of Steel Construction
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• v.19 no.5
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• pp.527-537
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• 2007

The main girders and cross-beams of an H-beam bridge consisted of factory-made H-beams, providing better conditions for quality control. Also, on-site fabrication works can be minimized and most of the stiffeners can be omitted, enabling simple and economic construction. In this study, the effect of the Multi-Stepwise TPSM (M-TPSM) on improving the maximum span length and section efficiency is analyzed. Compared to a 30-m-long, five-girder conventional plate girder bridge, structural analysis results showed that 50.7~55.1% of the girder height and 24.1~26.2% of the self-weight may be reduced by the application of M-TPSM to a five-girder H-beam bridge constructed with H-$900{\times}300$beams. In case of conventional H-beam bridges without M-TPSM, it was found that seven girders are required for a similar level of load-carrying capacity. Therefore, it is concluded that by the application of the M-TPSM, the H-beam bridge would become one of most cost-competitive options for short- and medium-span bridges.

• Food Engineering Progress
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• v.13 no.3
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• pp.216-220
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• 2009

The several functional properties of freeze-dried powder of Aloe vera gel was examined as influenced by pre-concentration degrees of the gel solution. As a pre-treatment prior to freeze drying, the gel solution was vacuum-concentrated by three levels (unit: g-water/g-solids) - high (H), 76; medium (M), 119; low (L), 159. In FT-IR spectra, the sample H showed the highest absorbance in the range of 1600-1550 $cm^{-1}$ and 1450-1400 $cm^{-1}$, which corresponded to level of the acetyl group in glucomannan. The sample H of freeze-dried powder was the highest in polysaccharide content, jack bean urease inhibition rate, and FAC (fat adsorption capacity). It could be inferred that the sample H had an effect on Helicobacter pylori inhibition and fat adsorption suppression according to urease inhibition rate and FAC, respectively.

• Journal of the Korean GEO-environmental Society
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• v.22 no.1
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• pp.5-12
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• 2021

Owing to economically efficient and easy installation, bucket foundation is a promising solution for offshore wind turbines. This paper aims at finding the behavior of suction caissons and soil surrounding the foundation by using three-dimensional finite element analysis. Under various loading conditions, a wide range of foundation geometries installed in dense and medium dense sandy soil was considered to evaluate ultimate horizontal load and overturning moment capacity. The results show that the rotation and displacement of the bucket due to monotonic loading are largely dependent on the foundation geometry, soil density and load eccentricity. Normalized diagrams and equations for the ultimate horizontal load and overturning moment capacities are presented that are useful tool for the preliminary design of such foundation type.

• The Journal of the Convergence on Culture Technology
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• v.9 no.4
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• pp.51-60
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• 2023

This study is to verify the moderating effect of residential selection on the relationship between marriage and childbirth. According to the analysis results, interactions of first marriage with the financial capacity of local governments for public services, residential stability, the scale of the region, and local economic situation have a moderating effect on childbirth. Interactions of remarriage and marriage with foreigners with the financial capacity of local governments for public services, residential stability, and the scale of the region have a moderating effect on childbirth. These results indicate that when married couples choose to reside in small and medium-sized cities or large cities rather than rural areas, it can more positively affect their intention to have children. While there may be a logical argument against advocating for regional integration based on the moderating effect of residential selection on the relationship between marriage and childbirth, the analysis results of this study and the phenomenon of married couples avoiding rural areas can contribute to raising the need for regional integration.

• Tribology and Lubricants
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• v.39 no.6
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• pp.235-243
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• 2023

This paper presents the fabrication process of water-lubricated plastic bearings. Plastic bearings require good mechanical properties and tribological properties as well as elasticity and shock resistance, especially when lubricated in dirty water conditions. In this study, sleeve-type plastic bearings are produced by winding a prepreg sheet, which primary contains nitrile rubber (NBR)-modified epoxy, self-lubricating fillers, and various types of lattice-structured reinforcing fibers such as carbon, Aramid, and polyethylene terephthalate. A thermosetting epoxy is chemically modified with NBR to impart elasticity and low-friction characteristics in water conditions. Experimental investigations are conducted to examine the mechanical and tribological characteristics of the developed bearing materials, and the results are compared with the characteristics of a commercial plastic bearing (Thordon SXL), well known as a water-lubricated bearing. A Thordon bearing (mainly composed of polyurethane) exhibits an extremely low load-bearing capacity and is thus only suitable for medium loading (1~10MPa). The tribological characteristics of the test materials are evaluated through Falex block-on-ring (LFW-1) friction and wear tests. The results indicate that friction exhibited by the carbon-fiber-reinforced NBR-10wt.%-modified epoxy composite material, incorporated with the addition of 20wt.% UHMWPE and 6wt.% paraffin wax, is lower than that of the Thorden bearings, whereas its wear resistance surpass that of Thorden ones. Because of these features, the load carrying capacity of the fabricated composite (>10MPa) is higher than that of the Thorden bearings. These results confirm the applicability of water-lubricated plastic bearing materials developed in this study.

• Journal of Korean Society of Forest Science
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• v.84 no.2
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• pp.266-274
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• 1995

Vegetational data from 62 quadrats of Pinus densiflora for. erecta and Chunyang-type of Pines densiflora forests were analyzed by using two multivariate methods : TWo-way INdicator Species ANalysis(TWINSPAN) for classification and Detrended Canonical Correspondence Analysis(DCCA) for ordination. The dominant tree species of Pinus densiflora for. erecta communities were found in the order of Pines densiflora for. erecta, Quercus mongolica, Quercus variabilis, Lindera obtusiloba, Fraxinus rhynchophylla, and Rhus trichocapa. The dominant tree species of Chunyang -type of Pinus densiflora communities were Quercue variabilis. Quercue mongolica, Fraxiraus sieboldiana, Styrax obassia, and Quercus serrata. The forest vegetation of Pinus densiflora was classified into Quercars variabilis-Styrax obassia. Quercus variabilis Quercus variabilis-Quercus mongolica, and Quercue mongolica communities according to TWINSPAN. Pinus densiflora for. erecta community was distributed in the good nutrition area of total nitrogen. organic matter, $K^+$, $Ca^{{+}+}$, $Mg^{{+}+}$, and canon exchange capacity, while Chunyang type of Pinus densiflora community in the good nutrition area of $P_2O_5$. The relationship between the distribution of dominant communities for forest vegetation and soil condition in Pinus densiflora communities was investigated by analysing the elevation and soil nutrition gradients. Quercus mongolica community was distributed in the high elevation and good nutrition area of total nitrogen, organic matter, and ration exchange capacity, while Quercus variabilis community was distributed in the low elevation and poor nutrition area of total nitrogen, organic matter, and ration exchange capacity. Quercus variabilis Styrax obassia and Quercus variabilis-Quercus mongolica community was distributed en the medium elevation and medium nutrition area.

• Korean Journal of Environment and Ecology
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• v.26 no.2
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• pp.210-218
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• 2012

This study was carried out to analyze the vegetation properties, soil characteristics and ordination of Bletilla striata population in South Korea. The $Bletilla$ $striata$ population was classified into $Juniperus$ $rigida$ dominant population, $Rhododendron$ $yedoense$ var. $poukhanense$ dominant population, $Rhus$ $javanica$ dominant population, $Bletilla$ $striata$ typical population. $Bletilla$ $striata$ were mainly distributed along the coast of south-western regions of the Korean penninsula and it's population was located at an elevation of 4m to 40m. In the study sites, soil organic matter, total nitrogen, available phosphate, exchangeable potassium, exchangeable calcium, exchangeable magnesium, cation exchange capacity and soil pH were 2.38-6.70%, 0.09-0.27%, 1.81-6.85mg/kg, 1.08-1.72$cmol^+/kg$, 3.56-7.71$cmol^+/kg$, 1.52-3.21$cmol^+/kg$, 5.28-16.95$cmol^+/kg$ and 4.60-6.01 respectively. $Rhododendron$ $yedoense$ var. $poukhanense$ dominant population was found in the steep sloped area that has high percentage of organic matter, total nitrogen, cation exchange capacity and pH than other populations. $Rhus$ $javanica$ dominant population was found in the gentle sloped area that has less percentage of organic matter, total nitrogen, cation exchange capacity and pH. $Juniperus$ $rigida$ dominant population and $Bletilla$ $striata$ typical population were found in the medium sloped area that has medium percentage of organic matter, total nitrogen, cation exchange capacity and pH. Current status of $Bletilla$ $striata$ habitats is very vulnerable with local development constantly threatening the species' survival. Thus, concrete conservation plans to protect natural habitats should be set up as soon as possible.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.233-236
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• 2006

This study was conducted to investigate somatic embryogenesis capacity using callus derived from bud meristems in sweetpotato. Shoot apical meristem explants $(height:150{\mu}m;base:\;350{\mu}m)$were cultured on MS medium supplemented with 1 mg/L 2/4-D. Embryogenic callus were observed in five cultivars when their shoot apices were cultured on MS medium supplements with 1 mg/L 2,4-D. After 6 weeks of culture, greater than 80% of the survived explants produced embryogenic calli and the calli gave rise to somatic embryos at frequencies of 72% (Yulmi), 60% (Shinhwangmi), 78% (Geonmi), 70% (KoKei 14), 40% (Sinjami). The regenerated plants developed into whole plantlets after they were transferred onto the fresh hormon-free MS medium of 74% (Yulmi), 82% (Shinhwangmi), 86% (Geonmi), 74% (Kokei 14), 41% (Sinjami) respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.248-254
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• 2015

There has been no previous study on technology development of large capacity drainage pump for rescue sinking ship in the country. The agricultural drainage pump was widely used for rescue sinking ship but this pump has several problems such as efficiency, low displacement and malfunction in winter. Therefore, this paper proposes to solve the problems for swiftly rescue sinking ship and develops the drainage pump system that has $20m^3/min$ mass flow rate specification at suction head 8 m. The centrifugal pump type the most commonly used in the field of naval architecture and ocean engineering was selected and designed based on the requirement specification. The blade design of impeller was derived from the Stepanoff coefficient and requirement specification and used computational fluid dynamics to review the target mass flow rate according to the impeller RPM at design operating conditions. We also performed structure analysis of the impeller to find structurally vulnerable points for the pump in service and completed the theoretical design of drainage pump system.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.4
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• pp.801-809
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• 2002

CSBHT is known to improve immunological response in mice and humans. In this study, CSBHT effect was examined in the context of CD4+ T cells' survival and TCR/CD3 induced activation responses. Spleen cells from 8 week BALB/c mice were cultured in CSBHT containing medium without activation for 24, 48 hr. The MTS assay and revealed that CSBHT did not stimulate spleen lymphocytes as mitogen. Spleen lymphocytes were treated with anti-CD3e/anti-CD28 antibodies for 48hr. Flow cytometry revealed that activity of T cell decreased with CSBHT concentration. CD4+ T cells were isolated and cultured ,in CSBHT containing medium for 48 hr. CSBHT did not affect survival of sorted CD4+ T cells without any involvement of APC. In order to evaluate the direct effect of CSBHT on helper T cells's proliferative capacity prior to activation, CD4+ T cells are isolated after 24hr of culture in CSBHT containing medium and activated with and without anti-CD3e/anti-CD28 activation for 48hr. A higher level of CD69 was observed in 1 ㎍/㎖ of CSBHT treatment than control using flow cytometry. But low CD69 expression was observed in 5㎍/㎖ of CSBHT treatment. Expression of mRNA for cytokines in CD4+ T cell revealed that IL-2 expression was increased in 1 ㎍/㎖. The expression of IL-2R α, INF- γ were increased with concentration. On the other hand mRNA of IL-4 was decreased in dose dependent manner. Results suggest that CSBHT may be desirable for CD4+ T cell's activity in immune responses. Further more, CSBHT may relatively activate Th1 and inactivate Th2.