• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.3
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• pp.132-142
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• 2007

In this study, a structural performance of R/C columns controlled by shear, strengthened with Sprayed FRP, was investigated. For this purpose, six 2/3-scaled column specimens were designed and tested by the pseudo-static reversed cyclic load under a constant axial load, which is 10% of the nominal axial strength of the column. Four specimens were strengthened by Sprayed FRP with different combinations of short fibers (carbon or glass) and resins (epoxy or vinyl ester). For comparison purpose, tests of a specimen strengthened with carbon fiber sheet (CFS) and a control specimen without strengthening were carried out, respectively. The result reveals that shear strengths and ductility capacities of columns strengthened with Sprayed FRP improved remarkably, compared to those of the control column, and the Sprayed FRP technique developed in this study is able to use the strengthening scheme of existing R/C columns.

• Journal of the Korea Concrete Institute
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• v.19 no.1
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• pp.121-130
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• 2007

To investigate the enhancement in strength and deformation capacities of concrete confined by FRP composites, tests under axial loads were carried out on three groups of thirty six short columns in circular section with diverse GFRP confining reinforcement. The major test variables considered include fiber content or orientation, wrap or tube type by varying the end loading condition, and continuous or discontinuous confinement depending on the presence of vortical spices between its two halves. The circumferential FRP strains at failure for different types of confinements were also investigated with emphasis. Various analytical models capable of predicting the ultimate strength and strain of the confined concrete were examined by comparing to observed results. Tests results showed that FRP wraps or tubes provide the substantial increase in strength and deformation, while partial wraps comprising the vertical discontinuities fail in an explosive manner with less increase in strength, particularly in deformation. A bilinear stress-strain response was observed throughout all tests with some variations of strain hardening. The failure hoop strains measured on the FRP surface were less than those obtained from the tensile coupons in all tests with a high degree of variation. In overall, existing predictive equations overestimated ultimate strengths and strains observed in present tests, with a much larger scatter related to the latter. For more accuracy, two simple design- oriented equations correlated with present tests are proposed. The strength equation was derived using the Mohr-Coulomb failure criterion, whereas the strain equation was based on entirely fitting of test data including the unconfined concrete strength as one of governing factors.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.203-210
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• 2002

In order to elucidate the growth mechanism of sulfide chimney formed as a result of seafloor hydrothermal mineralization, we carried out the mineralogical and fluid inclusion studies on the inactive, sulfide- and silica-rich chimney which has been recovered from a hydrothermal field in the Cleft segment of the Juan de Fuca Ridge. According to previous studies, many active and inactive vents are present in the Cleft segment. The sulfide- and silica-rich chimney is composed of amorphous silica, pyrite, sphalerite and wurtzite with minor amounts of chalcopyrite and marcasite. The interior part of the chimney is highly porous and represents a flow channel. Open spaces within chimneys are typically coated with colloform layers of amorphous silica. The FeS content of Zn-sulfides varies widely from 13.9 to 34.3 mole% with Fe-rich core and Fe-poor rims. This variation possibly reflects the change of physicochemical characteristics of hydrothermal fluids. Chemical and mineralogical compositions of the each growth zone are also varied, possibly due to a thermal gradient. Based on the microthermometric measurements of liquid-rich, two-phase inclusions in amorphous silica that was precipitated in the late stage of mineralization, minimum trapping temperatures are estimated to be about 1140 to 145$^{\circ}$C with the salinities between 3.2 and 4.8 wt.% NaCI equiv. Although the actual fluid temperatures of the vent are not available, this study suggests that the lowtemperature conditions were predominant during the mineralization in the hydrothermal field at Cleft segment. Comparing with the previously reported chimney types, the morphology, colloform texture, bulk chemistry, and a characteristic mineral assemblage (pyrite + marcasite + wurtzite + amorphous silica) of this chimney indicate that the chimney have been formed from a relatively low-temperature (<250$^{\circ}$C) hydrothermal fluid that was changed by sluggish fluid flow and conductive cooling.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.3
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• pp.385-392
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• 2012

This study was conducted to find out the optimum cropping system for the stable production of forage crops in the newly reclaimed land located at Gwanghwal and Gyehwa region of Saemangum reclaimed tide land from October, 2009 to October, 2011. Whole crop barley (WCB), Rye, Italyan-ryegrass (IRG) as winter crops and Corn, Sorghum${\times}$sudangrass hybrid (SSH) as summer crops were cultivated. Soil chemical properties, nutrient uptake, feed value, growth and yield were examinated. The testing soil was showed saline alkali soil where the contents of organic matter, available phosphate and exchangeable calcium were very low, while exchangeable sodium and magnesium were higher. Changes of soil salinity during the growing season of forage crops were less than 0.2%, and the growth of forage crops was not affected by salt injury. Standing rates of winter crops were higher in the order of Rye, WCB, and IRG, while the dry matter yield of winter crops was higher in the order of IRG, Rye and WCB. The highest crude protein (CP) content was recorded in IRG, and total digestive nutrients (TDN) contents were increased in the order of WCB, IRG, and Rye. The TDN content was higher in corn, whereas other feed value was higher in SSH. The content of mineral nutrients on stem, leaf and grain in IRG, Corn were high. After experiment pH was lowed, contents of exchangeable magnesium, sodium and organic matter were decreased while contents of total nitrogen, available phosphate and exchangeable potassium, calcium were increased. Winer crops and summer crops after continually cultivating in cropping system, fresh matter yield increased, compared to WCB-Corn (74,740 kg $ha^{-1}$), IRG-SSH 10%, IRG-Corn 7%, Rye-SSH 6%, Rye-Corn and WCB-SSH 3%. Dry matter yield increased, compared to WCB-Corn (20,280 kg $ha^{-1}$), IRG-SSH 7%, Rye-SSH 6%, IRG-Corn/Rye-Corn/WCB-SSH 3%. The TDN yield increased, compared to WCB-Corn (13,830 kg $ha^{-1}$), IRG-SSH 2%, WCB-SSH and IRG-Corn 1%. Therefore, we suggest that the crop combination of IRG-SSH and WCB-SSH would be preferred for silage stable production.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1A
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• pp.11-18
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• 2012

This paper deals with the numerical determination of the stress intensity factors of cracked aluminum plates under the mixed mode of $K_I$ and $K_{II}$ in glass-epoxy fiber reinforced composites. For the stress intensity factors, two different models are reviewed such as VCCT and two-step extension method. The p-convergent partial layerwise model is adopted to determine the fracture parameters in terms of energy release rates and stress intensity factors. The p-convergent approach is based on the concept of subparametric element. In assumed displacement field, strain-displacement relations and 3-D constitutive equations of a layer are obtained by combination of 2-D and 1-D higher-order shape functions. In the elements, Lobatto shape functions and Gauss-Lobatto technique are employed to interpolate displacement fields and to implement numerical quadrature. Using the models and techniques considered, effects of composite laminate configuration according to inclined angles and adhesive properties on the performance of bonded composite patch are investigated. In addition to these, the out-of-plane bending effect has been investigated across the thickness of patch repaired laminate plates due to the change of neutral axis. The present model provides accuracy and simplicity in terms of stress intensity factors, stress distribution, number of degrees of freedom, and energy release rates as compared with previous works in literatures.

• Polymer(Korea)
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• v.31 no.1
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• pp.14-19
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• 2007

Demineralized bone particle (DBP) has been used as one of the powerful inducers of bone and cartilage tissue specialization. In this study, we fabricated DBP/PLGA scaffold for tissue engineered disc regeneration. We manufactured dual-structured scaffold to compose inner cylinder and outer doughnut similar to nature disc tissue. The DBP/PLGA scaffold was characterized by porosity, wettability, and water uptake ability. We isolated and cultured nucleus pulposus (NP) and annulus fibrosus (AF) cells from rabbit intervertebral disc. We seeded NP cells into the inner core of the hybrid scaffold and AF cells into the outer portion of it. Cellular viability and proliferation were assayed by 3-(4,5-dimethylthiazole-2-yl) -2,5- diphenyltetrazolium -bromide (MTT) test. PLGA and PLGA/DBP scaffolds were implanted in subcutaneous of athymic nude mouse to observe the formation of disc-like tissue in vivo. And then we observed change of morphology and hematoxylin and eosin (H&E). Formation of disc-like tissue was better DBP/PLGA hybrid scaffold than control. Specially, we confirmed that scaffold impregnated 20 and 40% DBP affected to proliferation of disc cell and formation of disc-like tissue.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.267-273
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• 2005

To develop effective and powerful probiotic, Saccharomyces cerevisiae strains producing cellulolytic enzymes were genetically brooded. For the production of exoglucanase, the plasmid pVT-TExo (8.8 kb) was constructed, in which Thermomonosporafusca exoglucanase gene (E3) was under the control of ADHl promoter, and introduced into S. cerevisiae SEY2102. When the transformant, S. cerevisiae SEY2102/pVT-TExo, was cultivated on YPD medium, the total expression level of avicelase reached about 190 unit/l. The secretion efficiency and plasmid stability were about $50\%\;and\;91\%$, respectively. Recombination exoglucanase enzyme bound to avicel better than Clostridium endoglucanase (CelA) and Trichoderma endoglucanase (C4) enzymes. The mixing ratio of E3 and CelA displaying the best synergistic hydrolysis for avicel was observed at 4:1. The mixture of endoglucanase (CelA) and exoglucanase (E3) resulted in 3.2-fold increase of avicelase activity and 2.5-fold enhanced production of sugar production from avicel, compared to the single enzyme treatment.

• Archives of design research
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• v.20 no.1 s.69
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• pp.229-242
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• 2007

In Japan, a country renowned for her traditional respect for handicraft, superior craft techniques have been transmitted from generation to generation. Modern Japanese textiles reinterprete these traditional techniques in a new light and combine them with modern technology, to make modern Japanese industrial textile both futuristic and traditional simultaneously. This combining of new technology and handicraft serves as a reservoir for a remarkable diversity and originality in the development of new technology and design, and constitutes an important trend in modern industrial textiles. The aim of this study is to investigate the developmental background of Japanese textile industry that championed this trend to make the Japanese development unique in modern textile industries and to consider the concept of modern textiles as well as the structural innovation as represented by this new trend, thus contributing to the development of creative textiles for the present and the future. The findings of this study can be summarized as follows. The combining of new technology and traditional handicraft: 1) was made possible by Japanese consciousness that values traditional culture and by early recognition of advanced textile industry, which awarded new meaning and value to the traditional handicraft leading to an expanded social role for textiles. 2) helped construct a modern concept of textiles by pursuing textile media that are state-of-the-art, aesthetic, and highly sensitive to satisfy the requirements of modern industrial textile such as high quality, high performance, and high sensitivity. 3) enabled new design ideas and creation of new styles by implementing structural innovation in industrial textiles that involved diversification of expression, diversity in materials, and emphasis on texture. In short, by combining new technology and traditional handicraft, Japan came up with a new sense of aesthetics that is highly original and high level and with which the rest of the world can easily sympathize, thereby presenting one of the most important guiding principles for future textiles.

• Journal of the Korean Society of Food Culture
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• v.16 no.2
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• pp.180-186
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• 2001

The purpose of this study was to investigate the sensory and physicochemical attributes of Cham-chwi dduk with various amounts of Cham-chwi(Aster scaber) and salt. Cham-chwi dduk was made by steaming glutinous rice flour with Cham-chwi powder for 15 min. Cham-chwi powder was added 1, 3, 5% of glutinous rice flour weight and salt was added 0.5, 1.0 1.5%. According to the sensory evaluation, bitterness and Cham-chwi flavor increased as the amount of Cham-chwi increased and saltiness increased as the amount of salt increased(p<0.05). In the textural profiles, chewiness, adhesiveness, hardness and gumminess were highest when 3% Cham-chwi was added. The moisture content of Cham-chwi dduk was increased as the amount of Cham-chwi was increased and the amount of salt was decreased. The more amount of added Cham-chwi increase, the more green color was strong and yellow color was weak. These results were used to determine the optimum conditions of adding levels of Cham-chwi and salt. Conditions were standardized with minimum range of firmness when expected value of Cham-chwi flavor was more than six and expected value of bitterness was less five. The optimum conditions of Cham-chwi dduk was established as the 3.1% Cham-chwi and 0.6% salt.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.2
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• pp.97-104
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• 2006

This experiment was carried out to determine the effect of harvesting date on the forage yield and quality of different rye (Secale cereale L.) cultivars. The experiment was conducted in split plot design with three replications. The main plots consisted of two harvesting dates 20th and 30th April. The subplots consisted of five rye cultivars from different maturity groups such as 'Kodiak (Late)'. 'Koolgrazer (Early)', 'Danko (Late)', 'Homil22 (Medium)' and 'Olhomil (Early)' Dry matter (DM) contents of 17.8% at early harvesting were lower 2.2% than at late harvesting. But crude protein (CP) of 18.9% and total digestible nutrients (TDN) contents of 65.5% at early harvesting were higher 2.3% and 3.0% than those at late harvesting, respectively. There were significant differences in DM, CP and TDN contents among the rye cultivars tested (p<0.05). The contents of fiber components at early harvesting were lower than those at late harvesting. The acid detergent fiber (ADF), neutral detergent fiber (NDF), cellulose and acid detergent lignin (ADL) contents at early harvesting were lower than those at late harvesting, and hemicellulose contents at early harvesting was higher than that at late harvesting. The fiber component of early maturing cultivars such as 'Koolgrazer' and 'Olhomil' were higher than those of the others. Dry matter, CP, in vitro digestible dry matter (IVDDM) and TDN yields at early harvesting were lower than those at late harvesting, and the yield of early maturing cultivars were higher than those of the others. In this study, the results of this study indicate that forage production technology in combination with early maturing rye cultivar and late harvesting could enhance both production and quality of rye.