• Economic and Environmental Geology
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• v.49 no.2
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• pp.105-120
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• 2016

Most of riverside in Korea, in case of application of water curtain cultivation (WCC) technique, has been inveterately suffering from the gradual drawdown of groundwater level and related shortage of water resources during the WCC peak time. We believe that the water resources issue in these riverside areas can be effectively solved when the interaction between groundwater and nearby surface water is well understood. To investigate the connection between stream and ground water, and the influence of stream water on the nearby aquifer, this study examined the water temperature and oxygen and hydrogen stable isotopic compositions. The study area is well-known strawberry field applying the WCC technique in Sangdae-ri, Gadeok-myon, Cheongju City, and the sampling was done from February 2012 through June 2014 for stream and ground water. Some groundwater wells near stream showed big temporal variations in water temperature, and their oxygen and hydrogen stable isotopes showed similar compositions to those of adjacent stream water. This indicates that the influence of stream water is highly reflected in the stable isotopic composition of groundwater. Four cross-sectional lines from stream to hillside were established in the study area to determine the spatial differences in water quality of wells. At the late stage of WCC in February to March, groundwater of wells in line with short cross-sectional length showed the narrow range of isotopic compositions; however, those in the long cross-sectional line showed a wide compositional range. It was shown that the influence of the stream water at the late WCC stage have reached to the distance of 160 to 165 m from stream line, which is equivalent to the whole length and one-third point in each short and long cross-sectional line, respectively. Therefore, the wide compositional range in the long cross-sectional lines was not only due to the influence of stream water, but apparently resulted from the change of relative impact of each groundwater supplying from two or more aquifers. In view of stable isotopic compositions, there seems to be three different aquifers in this study area, which is competing for dominance of water quality in wells at each period of WCC.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.41-41
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• 2008

In general, polyimides (PIs) are used in alignment layers in liquid crystal displays (LCDs). The rubbing alignment technique has been widely used to align the LC molecules on the PI layer. Although this method is suitable for mass production of LCDs because of its simple process and high productivity, it has certain limitations. A rubbed PI surface includes debris left by the cloth, and the generation of electrostatic charges during the rubbing induces local defects, streaks, and a grating-like wavy surface due to nonuniform microgrooves that degrade the display resolution of computer displays and digital television. Additional washing and drying to remove the debris, and overwriting for multi-domain formation to improve the electro-optical characteristics such as the wide viewing angle, reduce the cost-effectiveness of the process. Therefore, an alternative to non-rubbing techniques without changing the LC alignment layer (i.e, PI) is proposed. The surface of LC alignment layers as a function of the ion beam (IE) energy was modified. Various pretilt angles were created on the IB-irradiated PI surfaces. After IB irradiation, the Ar ions did not change the morphology of the PI surface, indicating that the pretilt angle was not due to microgrooves. To verify the compositional behavior for the LC alignment, the chemical bonding states of the ill-irradiated PI surfaces were analyzed in detail by XPS. The chemical structure analysis showed that ability of LCs to align was due to the preferential orientation of the carbon network, which was caused by the breaking of C=O double bonds in the imide ring, parallel to the incident 18 direction. The potential of non-rubbing technology for fabricating display devices was further conformed by achieving the superior electro-optical characteristics, compared to rubbed PI.

• Transactions on Electrical and Electronic Materials
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• v.6 no.5
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• pp.202-209
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• 2005

Phase evolution, microstructure and the electrical properties such as $k_p$ and $Q_m$ of $Pb(Mg_{1/3}Nb_{2/3})O_3[PMN]-Pb(Mn_{1/3}Nb_{2/3})O3[PM'N]-PbZrO_3[PZ]-PbTiO_3[PT]$ quaternary system were investigated within the compositional ranges $0{\leq}y{\leq}0.125$, y+z=0.125, and $0.39{\leq}x{\leq}0.54$ of the formula $Pb_{0.97}Sr_{0.03}[Mg_{1/3}Nb_{2/3})_y\;(Mn_{1/3}Nb_{2/3})_z\;(Zr_{x}Ti_{1-x})_{1-(y+z)}]O_3$. In the case of increasing Mn/(Mg+Mn) ratio for a fixed Zr/Ti ratio of 47.5/52.5, phase relation remained unchanged but the grain size drastically decreased, and the electrical properties changed as following: both $k_P$ and $Q_m$ reached the peak values at $Mn/(Mg+Mn)\cong0.3l7$ and gradually decreased; $\varepsilon33^T$ showed a monotonic decrease; P-E hysteresis loop gradually changed to asymmetrical one, and $E_i$ increased in correspondence. With increasing Zr/Ti ratio for a fixed Mn/(Mg+Mn) ratio of 0.317, on the contrary, the cell parameter $(\alpha^2c)^{1/3}$ gradually increased, and tetragonal-rhombohedral morphotropic phase boundary appeared in the range of $51/49{\leq}Zr/Ti{\leq}54/46$. the meantime, the grain size substantially increased, and the electrical properties changed as following: $k_P$ and $\varepsilon33^T$ reached peak values at Zr/Ti=51/49 and 48/52, respectively, and then gradually decreased; change of $Q_m$ was adverse to $k_P$; both $E_C\;and\;E_i$ considerably decreased while $P_S$ moderately increased. For the system 0.125(PMN+PM'N)-0.875PZT studied, the composition Mn/(Mg+Mn)=0.3l7 and Zr/Ti=51/49 revealed some promising electrical properties for piezoelectric transformer application such as $k_P=0.58,\;Q_m\cong1000$, and $\varepsilon^T_{33}=970$, as well as dense and fine-grained microstructure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.35-36
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• 2008

PTC thermistor are characterized by an increase in the electrical resistance with temperature. The PTC materials of middle Curie point were produced or that of high Curie point (above $200^{\circ}C$), it was determined that compositional modifications of $Pb^{2+}$ for $Ba^{2+}$ produce change sin the Curie point to higher temperature. PTC ceramic materials with the Curie point above $120^{\circ}C$ were prepared by adding $PbTiO_3$, PbO or $Pb_3O_4$ into $BaTiO_3$. Thereby, adding $Pb^{2+}$ into $BaTiO_3$-based PTC material to improve Tc was studied broadly, however, weal know that PbO was poisonous and prone to volatilize, then to pollute the circumstance and hurt to people, so we should dope other innocuous additives instead of lead to increase Tc of composite PTC material. In order to prepare lead-free $BaTiO_3$-based PTC with middle Curie point, the incorporation on $Bi_{1/2}K_{1/2}TiO_3$ into $BaTiO_3$-based ceramics was investigated on samples containing 0, 1, 2, 3, 4, and 50mol% of $Bi_{1/2}K_{1/2}TiO_3$. $Bi_{1/2}K_{1/2}TiO_3$ was compounded as standby material by conventional solid-state reaction technique. The starting materials were $Bi_2O_3$, $K_2CO_3$, $BaCO_3$ and $TiO_2$ powder, and using solid-state reaction method, too. The microstructures of samples were investigated by SEM, DSC, XRD and dielectric properties. Phase composition and lattice parameters were investigated by X-ray diffraction.

• The Journal of the Petrological Society of Korea
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• v.5 no.1
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• pp.52-65
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• 1996

Precambrian metamorphic rocks of the Cheongpyeong-Yangpyeong area, central Gyeonggi massif, comprise gneiss, schist, quartzite and amphibolite. Mineral, assemblages of pelitic gneisses are characterized by biotite + cordierite + garnet + sillimanite + K-feldspar + plagioclase + quartz together with minor muscovite, spinel and corundum, and represent the granulite facies metamorphism. In particular, kyanite occurs as fine-grained relict phase inside plagioclase of three gneiss samples. Metamorphic conditions are estimated from garnet-biotite and garnet-cordierite geothermometers in conjunction with garnet-$Al_2SiO_5$-quartz-plagioclase (GASP) and garnet-rutile-$Al_2SiO_5$-ilmenite (GRAIL) geobarometers. They are 700-$850^{\circ}C$ and 3.2-8.3 kbar, and 580-$690^{\circ}C$ and 2.1-3.2 kbar, respectively, when the core and rim compositions of garnet are use. Garnet of the GASP assemblage increases rimward in the Fe and Mn contents but decreases in the Mg content, whereas its Ca content does not vary significantly. Together with the occurrence of relict kyanite and the result of P-T estimates, compositional zoning patterns of garnet indicate a clockwise P-T history. Moreover, the preservation of high-pressure minerals such as kyanite in plagiocalse, even after the medium-pressure granulite facies metamorphis, suggests a rapid change in P-T conditions.

• Journal of the Korean Ceramic Society
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• v.25 no.3
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• pp.207-216
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• 1988

Effect of $SO_3$ on the formation of $C_3S$ and its properties were investigated through studies for diffusion of reacting component, the size variation of $C_3S$ and compositional change of the phases in the clinker. When less than 2.0% of $SO_3$ was added to the clinker composition, the formation of $C_3S$ was enhanced, however, addition of more than 2.0% of $SO_3$ rather restrained the reaction remarkably. The diffusion coefficient of Si into the melt was about $3.6~4.2{\times}10^{-7}Cm^2$/sec and it was slightly decreased with the amount of $SO_3$. The crystal size of $C_3S$ formed in the clinker was grown gradually according to the amount of $SO_3$, when more than 1.0% of $SO_3$ was added. With increasing of $SO_3$ content in the clinker composition of CaO and decreasing of $SiO_2$ were found in the melt of the clinker. Consequently, it is considered that the decreasing of $C_3S$ formation is caused by dissolution and transportation of CaO component into liquid phase is interrupted.

• Herbal Formula Science
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• v.20 no.2
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• pp.177-186
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• 2012

In this study, we selected some herbal formulation about a series of Chijasi-tang in Dongeuibogam by using web-based open program;Prescription Lineage Graph (http://164.125.206.43/PrescriptionLineageGraph.aspx). And we compared and analyzed the changes of efficacy, major target symptoms of each herbal formulation according to compositional variation of each herbal formulation. Chijasi-tang, first appeared in Sanghanlun, consists of Capejasmine and Fermented soybean, and it is mainly used to treat insomnia due to vexation, heartburn and yellow greasy tongue fur. Capejasmine can clear away irritable feverish sensation in chest by flowing downward the heat, and Fermented soybean can disperse stagnated heat throughout the chest by expelling stagnated heat from the exterior In the case of the heat stagnation caused by relapsing of disease due to overstain, Chisijisil-tang can be used. And if symptom appear more on the upper or exterior than a case of Chisijisil-tang, Seosisi-tang could be more suitable, if half exterior and half interior, Omae-tang could be for it. In addition, if symptom caused by relapsing due to improper diet, Chisijihwang-tang could be proper formulation. In the case of the heat stagnation body inside and jaundice, if it is caused by alcohol, Chijadaehwang-tang could be used for the purpose of urgent purgation, Galchul-tang would be suitable for helping the function of the spleen and the stomach and for treatment of damp-heat of the spleen and the stomach. And if it is caused by pandemic infection, Jangdal-hwan would be good formulation for it. Samhwangseokgo-tang and Yangdokchija-tang could be appropriate formulation for the raging of noxious heat and pathogenic fire caused by febrile disease with toxic yang. Daehwangeum-ja is for severe constipation due to heat-dryness with stagnated fever, Haebaek-tang is appropriate for severe diarrhea due to heat type change of Soeum. According to the result of our investigation, although there are various target causes and symptoms of each herbal formulations, whatever pathogenetic cause is, the stagnated heat in interior side is the basis of symptoms. Therefore, the purpose of including Chijasi-tang in composition of each herbal formulation is treatment of the stagnated heat. For such reason, on the fundamental or ancillary basis of Chijasi-tang plus some herbs for each therapeutic purpose.

• Korean Journal of Human Ecology
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• v.11 no.3
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• pp.273-285
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• 2002

Three materials for sport underwear were manufactured by order for study, and among them, suitable material in order to perform an experiment on the effect of wearing was adopted. The results are as follows: The result of wearing an experimental clothes for sports manufactured as a foundation-type underwear for sports showed that if the same compositional materials were applied, laminating material had higher rate than that of others in the amount of sweat. Concerning relative humidity in clothes and the amount of sweat absorbed in clothes among the two kinds of materials which were produced by laminate, material 2(nylon+modal) was statistically exerts higher influence on the amount of sweat. The humidity in clothes keeps the optimal condition of 59.8%, and breast part showed the highest relative humidity. The material 2(nylon+modal) showed the highest comfortableness, the sense of warmth, humidity and voluminousness, and the sense of pressure. Follow-up survey revealed that in case of material 2, higher amount of sweat than that of the group objects in its early phase, and the amount of sweat varies from individuals. The temperature in clothes of folded parts of experimental clothes and maximum surface temperature was equivalent to that of average skin. With the lapse of time, the weight decreased of 11.03% in maximum, and 3.12% in minimum. The amount of change in the girth was greater in part of body frame than that of limbs, and especially, navel and waist part showed high decrease, and upper breast, breast and the largest part of abdomen showed relatively low decrease. The above experiment revealed that materials for suitable to the underwear for sports for loss of weight by an exercise should be made of doubled-nylon and modal, along with the laminate processing, which heightens the amount of sweat. Thus, wearing an experimental wear gave satisfaction in the view of the beauty of appearance as it did not discharge flowing secretion to the outside at the time of exercise.

• Corrosion Science and Technology
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• v.9 no.4
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• pp.147-152
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• 2010

Conventional paints for conversion coating applications in steel production derived mainly from water-based polymer dispersions containing several additives actually show good general performance, but suffer from poor scratch and abrasion resistance during use. The reason for this is because the relatively soft organic binder matrix dominates the mechanical surface properties. In order to maintain the high quality and decorative function of coated steel sheets, the mechanical performance of the surface needs to be improved significantly. In fact the wear resistance should be enhanced without affecting the optical appearance of the coatings by using appropriate nanoparticulate additives. In this direction, nanocomposite coating compositions (Nanomer$^{(R)}$) have been derived from water-based polymer dispersions with an increasing amount of surface-modified nanoparticles in aqueous dispersion in order to monitor the effect of degree of filling with rigid nanoparticles. The surface of nanoparticles has been modified for optimum compatibility with the polymer matrix in order to achieve homogeneous nanoparticle dispersion over the matrix. This approach has been extended in such a way that a more expanded hybrid network has been condensed on the nanoparticle surface by a hydrolytic condensation reaction in addition to the quasi-monolayer type small molecular surface modification. It was expected that this additional modification will lead to more intensive cross-linking in coating systems resulting in further improved scratch-resistance compared to simple addition of nanoparticles with quasi-monolayer surface modification. The resulting compositions have been coated on zinc-galvanized steel and cured. The wear resistance and the corrosion protection of the modified coating systems have been tested in dependence on the compositional change, the type of surface modification as well as the mixing conditions with different shear forces. It has been found out that for loading levels up to 50 wt.-% nanoparticles, the mechanical wear resistance remains almost unaffected compared to the unmodified resin. In addition, the corrosion resistance remained unaffected even after $180^{\circ}$ bending test showing that the flexibility of coating was not decreased by nanoparticle addition. Electron microscopy showed that the inorganic nanoparticles do not penetrate into the organic resin droplets during the mixing process but rather formed agglomerates outside the polymer droplet phase resulting in quite moderate cross linking while curing, because of viscosity. The proposed mechanisms of composite formation and cross linking could explain the poor effect regarding improvement of mechanical wear resistance and help to set up new synthesis strategies for improved nanocomposite morphologies, which should provide increased wear resistance.

• YAKHAK HOEJI
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• v.40 no.3
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• pp.311-319
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• 1996

DWP305, a preparation containing combination of ursodeoxycholic acid(UDCA), silymarin and vitamins ($B_1\;and\;B_2$), is a drug currently being developed for hep atic disorders. In order to evaluate the changes in hepatic function by multiple oral administration(2 and 4 weeks) of DWP305 in rats, several biochemical parameters in blood, bile acid composition, and the accumulation of UDCA and lithocholic acid(LCA),a toxic metabolite formed by enterobacteria, were examined using HPLC. In blood biochemical findings, DWP305 did not affect the normal level and there was no difference in total bile acid composition for UDCA, cholic acid(CA), deoxycholic acid(DCA), chenodeoxycholic acid(CDCA) and LCA compared to the UDCA administered group, although total ratio of UDCA and CA was different from normal group. In case of ratio of taurine and glycine conjugated forms, DWP305(186mg/kg as a UDCA) administered group was also similar to normal group and UDCA administered group, while high dosing of DWP305 was not different in the ratio of UDCA administered group(930mg/kg) but normal group. And the ratio of LCA was in order of UDCA(930mg/kg), DWP305(930mg/kg as a UDCA), UDCA(186mg/kg) and DWP305(186mg/kg as a UDCA) administered group, which was less than 4%. The free form of UDCA as well as most of bile acids was not detected at all in rat liver, indicating that there's no accumulation. These results suggest that multiple dosing of DWP305 in rats may not affect hepatic biotransformation and metabolism of bile acids.