• Journal of the Korean Ceramic Society
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• v.37 no.8
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• pp.768-773
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• 2000

Alnite clinker, which is based on CaO-SiO2-CaCl2 system, was synthesized by recycling Cl-containing waste, and its hydraulic properties were onvestigated. Alinite coinkers with two different chemical compositions were burned for 10∼30 minutes in the range of temperature, 1350∼1450$^{\circ}C$. The microstructures of those clinkers were characterized by powder X-ray diiffracuion analysis, optical microscope, and scanning electronic microscope and heat of hydration of alinite cements which was measured in order to investigate hydraulic properties. X-ray analysis shwoed that f-CaO in both clinkers with different compositions significantly was decreased with transforming C2S(belite) to C3S(alite). From the results of microscopy and scanning electron microscopy(SEM), crystal of synthesized alite(C3S) was larger and better crystallinity than that of ordinary portland cement.

• Food Science and Preservation
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• v.4 no.1
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• pp.1-10
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• 1997

This study was performed to determine chemical compositions of dried persimmons stored with plastic film at low temperature and the effect of film packaging on dried persimmons during storage. The moisture contents of dried persimmons were 30 to 36% and alcohol contents were 264 to 318 mg/100g and acetaldehyde contents were 25 to 40mg/100g. Total lipid contents of dried persimmon were 626 to 869mg/100g and oleic, palmitic, linolenic, and palmitoleic acid were major fatty acids in total lipids. Major amino acids were glutamic acid, arginine, cystine and aspartic acid. From the result of storage experiment, non-packed group was that hardness was high as decreased in moisture content. In case of film packed groups stored at 5$^{\circ}C$, self life was longer than non-packed and packed groups stored at room temperature. But, it need to develop available packing material and storage method.

• Journal of Adhesion and Interface
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• v.18 no.2
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• pp.68-74
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• 2017

Epoxy resins are widely used in various fields due to their excellent thermal, mechanical and chemical properties. In order to improve the mechanical properties of the epoxy composition after curing, various materials are mixed in the epoxy resin. Among the nano materials, CNT is the most widely used. However, CNT has limitations in terms of manufacturing process and manufacturing cost. Therefore, there is a growing interest in naturally occurring HNTs having similar structure to that of CNT. In this study, the thermal and mechanical properties of epoxy compositions containing HNTs treated with two types of silane compounds were investigated. The mechanical properties of silane-treated HNT were measured by using a universal testing machine. The differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis (TMA) were used to measure thermal properties. As a result of the above tests, when the HNT was surface-treated with aminosilane, the tensile strength of the epoxy composition containing the HNT was higher than that of the epoxy composition containing epoxy silane treated HNT. The linear thermal expansion coefficients (CTE) obtained from the thermomechanical analysis of the two epoxy compositions for the comparison of dimensional stability showed that the HNT composition treated with aminosilane showed a lower value of CTE than that of epoxy composition including the pristine HNT.

• Journal of Ecology and Environment
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• v.38 no.4
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• pp.505-515
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• 2015

The objectives of this study were to determine the effects of stream nutrient regime, N:P ratios and suspended solids on fish tolerance/trophic compositions and stream ecosystem health, based on multi-metric model, during 2008-2013. Also, stream ecosystem health was evaluated in relation to chlorophyll-a (CHL) as a measure of algal productivity or indicators of trophic state to water chemical parameters. Total number of sampled fish species were 50 and showed a decreasing trend from 2008 to 2013. The minnow of Zacco platypus, based on the catch per unit effort (CPUE), was the most dominant species (25.9%) among the all species. Spatial heterogeneity was evident in the fish tolerance guilds that showed the dominance of sensitive species (89%) in the headwaters (S1) and the dominance of tolerant species (57%) in the urban. These conditions were directly influenced by concentrations of nutrients and organic matter (COD). The N:P ratios, as a barometer of water pollution, had a negative linear function (R² = 0.40, P < 0.01) with CHL, and the ratios had an important role in changes of COD concentration (R² = 0.40, P < 0.01). Under the circumstances, the N:P ratio directly influenced the relative proportions of fish trophic/tolerance compositions. According to the regression analysis of omnivore (O_m) and insectivore sp. (I_n) on total nitrogen and total phosphorus, nitrogen had no significant influences (P > 0.05) to the two compositions, but phosphorus influenced directly the two guilds [slope (a) = -32.3, R² = 0.25, P < 0.01 in the I_n; a = 40.7, R² = 0.19, P < 0.01 in the O_m]. Such water chemistry and fish trophic guilds determined the stream ecosystem health, based on the multi-metric fish model.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.3
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• pp.347-357
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• 2011

The TSP aerosols were collected at Gosan site of Jeju Island between 2003 and 2007, and their aerosol components were analyzed to examine the variations of chemical compositions with the corresponding pathways of inflowing air parcels. According to the comparison of seasonal aerosol compositions, the soil-originated components showed remarkably high concentrations during spring season. On the other hand, the concentrations of anthropogenic components were somewhat high in spring and summer seasons, but low in fall season. Based on the comparison of TSP compositions in relation to the pathways of inflowing air mass, the concentrations of anthropogenic components (nss-$SO_4^{2-}$, S, $NO_3^-$), soil-originated components (nss-$Ca^{2+}$, Al, Fe, Ca), and the heavy metals (e,g., Mn, Zn, Cr, Pb, Cu, Cd, etc.) have relatively increased with the air mass moving from China continent into Jeju area. Meanwhile, the marine-originated components showed an increasing trend with the air mass coming from North Pacific Ocean. In the seasonal and sectional comparison, the nss-$SO_4^{2-}$, $NO_3^-$, nss-$Ca^{2+}$, and Al showed comparatively high concentrations when the air mass moved from China continent during all seasons. Especially, the $NO_3^-$, nss-$Ca^{2+}$, and Al concentrations were somewhat high when the air mass moved from Korean Peninsula during summer season. It was also recognized that the Na+ concentration were high, when the air mass moved from Pacific Ocean through all seasons.

• The Plant Pathology Journal
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• v.23 no.2
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• pp.97-102
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• 2007

A total of 39 essential oils were tested for antifungal activities as volatile compounds against five phytopathogenic fungi at a dose of 1 ${\mu}l$ per plate. Five essential oils showed inhibitory activities against mycelial growth of at least one phytopathogenic fungus. Origanum vulgare essential oil inhibited mycelial growth of all of the five fungi tested. Both Cuminum cyminum and Eucalyptus citriodora oils displayed in vitro antifungal activities against four phytopathogenic fungi except for Colletotrichum gloeosporioides. The essential oil of Thymus vulgaris suppressed the mycelial growth of C. gloeosporioides, Fusarium oxysporum and Rhizoctonia solani and that of Cymbopogon citratus was active to only F. oxysporum. The chemical compositions of the five active essential oils were determined by gas chromatography-mass spectrometry. This study suggests that both E. citriodora and C. cyminum oils have a potential as antifungal preservatives for the control of storage diseases of various crops.

• Economic and Environmental Geology
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• v.9 no.2
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• pp.85-106
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• 1976

The Bulgugsa acidic igneous rocks of the late Cretaceous age are largely distributed in Busan area, which is located in the southeastern corner of the Korean Peninsula. These igneous rocks comprise in ascending order, felsite, dacitic-rhyolitic welded tuffs, granite porphyry and granitic rocks. The former three members represent the early phase of volcanic activities, so that they are named as Jangsan volcanic rocks. The granitic rocks consist of granodiorite, hornblende biotite granite, Kumjongsan granite, fine grained granite, and Daebyen granite, represent the late phase of igneous activities. The Kumjongsan grainte, the largest pluton of the granitic mass, emplaced between two great vertical faults trending NNE. New chemical analyses of 33 rock samples of these acidic rocks are given. Their chemical compositions are generally similar to those of the late Mesozoic acidic igneous rocks of the northern Ashio mountains, and C-Zone granite group of the Ogcheon geosyncline, with their characteristic variation trends of several oxides. Their chemical compositions also show that $Al_2O_3$ is high value, and differentiation index is high, too. Systematically developing joints in Kumjungsan granite are divisible into two types at least. One is the NS-N $20^{\circ}E$ trendirig, $85^{\circ}{\sim}90^{\circ}$ dipping type of joint system which coincides with the trends of distribution of the granite mass and the dikes intruding this granite. Joints of this type may be cooling joints generated as tension cracks. The other is the $N60^{\circ}{\sim}70^{\circ}W$ or $N40^{\circ}{\sim}60^{\circ}E$ trending type of joint systems. It is considered that. joints belonging to this type may be shear joint occurring under the state of south-north tectonic couple acting at the east and west side of the granite mass. Igneous activities of the the Bulgugsa acidic igneous rocks in Busan area was taken place as. follows, formation of the magma reservoir, eruption and intrusion of felsite, consolidation of vents. and increasing vapor pressure in magma reservoir, eruption of pyroclastic flows, caldera collapse, intrusion of granite porphyry, and intrusion of granitic rocks at the latest stage.

• Korea-Australia Rheology Journal
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• v.17 no.1
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• pp.1-7
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• 2005

Acrylonitrile-Butadiene-Styrene (ABS), polycarbonate (PC) and their alloys are an important class of engineering thermoplastics that are widely used for automotive industry, computer and equipment housings. For the process of recycling mixtures of ABS and PC, it is desirable to know how sensitive the blend properties are to changes in compositions. It was for this reason that blends of virgin ABS and virgin PC at five different compositions, namely, $15\%,\;30\%,\;50\%,\;70%$ and $85\%$ by weight of ABS were prepared and characterised by rheological and mechanical measurements. Rheological properties of these blends in steady, oscillatory and transient step shear and mechanical properties, namely, tensile strength, elongation-at-break and Izod impact strength are reported. The results show that PC behaves in a relatively Newtonian manner, but ABS exhibits significant shear thinning. The ABS-rich blends show a trend that is similar to that of ABS, while PC-rich blends, namely $0\%$ and $15\%$, exhibit a nearly Newtonian behaviour. However, at a fixed shear rate or frequency, the steady shear or the dynamic viscosity varied respectively in a non-mono-tonic manner with composition. Except for $15\%$ blend, the viscosities of other blends fall into a narrow band indicating a wide-operation window of varying blend ratio. The blends exhibited a lower viscosity than either of the two pure components. The other noticeable feature was that the blends at $70\%$ and $85\%$ ABS content had a higher G' than pure ABS, indicating an enhancement of elastic effect. The tensile yield strength of the blends followed the 'rule of mixtures' showing a decreasing value with the increase of ABS content in PC. However, the elongation-at-break and the impact strength did not appear to obey this 'rule of mixtures,' which suggests that morphology of the blends also plays a significant role in determining the properties. Indeed, scanning electron micrographs of the fracture surfaces of the different blends validate this hypothesis, and the $15\%$ blend is seen to have the most distinct morphology and correspondingly different behaviour and properties.

• Fashion & Textile Research Journal
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• v.15 no.1
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• pp.138-146
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• 2013

Chemical compositions and biological functions of brown colorants extracted from pine bark(Pinus densiflora) have been studied. Dyeing test using multifiber fabrics with extracted colorants were preliminary carried out. Dyeing conditions and fastness tests of selected fabrics have been also studied. The brown colorants were produced 1.5% concentrations by solvent extraction from milled pine bark using methanol. The colorants were extracted with 80% methanol as best choice by a criteria of solid quantity and dyeability on fabrics. The chemical compositions were identified as mixtures of taxifolin epicatechin and procyanidin by LC/MS analysis. The brown colorants could be dyed not only natural fibers such as cotton, silk and wool but also synthetic fiber as nylon and semi-synthetic fiber as viscose rayon. Maximum K/S values was shown at 400 nm according to different fiber with color appearance of redish brown. Optimum pH and temperature of dyeing conditions was 4 and above $80^{\circ}C$, respectively. The brown colorants had a strong antioxidant activity compared to Butylated hydroxyanisole as standard and weak antimicrobial activity against E. coli. compared to kanamycin. Washing, rubbing, perspiration, dry cleaning and light fastness for cotton, nylon and silk dyed with the brown colorants were carried out by KS K method. Most of color fastness such as washing, rubbing, perspiration, and dry cleaning were represented as 4-5 grade. However, light fastness was reported as 2-3 grade. From this studies, brown colorants produced pine bark have a high potentials for natural dyeing on fabrics with antioxidant activity.

• The Journal of Engineering Geology
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• v.27 no.1
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• pp.1-7
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• 2017

Seawater intrusion was evaluated using electrical conductivity, chemical proxies, and oxygen isotopic compositions in coastal area. It seems that groundwater in the area where the electrical conductivity is over $3,000{\mu}S/cm$ is influenced by seawater. However, it is very difficult that seawater intrusion is distinguished from other contaminants using the electrical conductivity. The chemical proxies and oxygen and hydrogen isotopic compositions can quantitatively estimate seawater intrusion. However, these method is a costly disadvantage. Therefore, firstly, groundwater contamination by seawater intrusion was evaluated using electrical conductivity and then the additional chemical and isotopic analysis were conducted in areas where possibility of contamination by seawater intrusion is high. These systematic analytical method can reduce analytical cost to quantitatively evaluate influence of seawater intrusion on coastal groundwater and may improve efficiency of analytical method for seawater intrusion.