• Korean Journal of Human Ecology
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• v.17 no.5
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• pp.1027-1035
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• 2008

Essentail oils and carrier oils are generally used for Aromatherapy. Therefore the toxicity, possibilities of irritations and sensitive reactions and injury of essential oils must be considered for clients and therapists. So that, in this studies a toxicity of jojoba and 4 species essential oils (fennel, mandarine, tea tree and cedarwood) were investigated by the measurement of MTT-assay and sirius red staining. Liver, kidney and brain tell were chosen for the cell viability assay and observation of morphological change. In the result, no cytotoxicity was observed on live., kidney and brain cell at concentration of 0.01 $\mu\el/m\el$ jojoba oil. And lysis and nucleus breaking were not observed at same concentration of jojoba oil on live., kidney and brain cell. fennel oil was showed 50% of cell viability and inhibited cell growth on liver, kidney and brain cell at relatively high concentration compared with the other oils. 50% of liver, kidney and brain cell viability and delayed cell growth of tea tree and mandarine oil were revealed at lower concentration than fennel oil. In cedarwood oil, 50% of liver cell viability at concentration of 0.00067 $\mu\el/m\el$ was showed, but cell viability and cell growth of kidney and beam cell were effected at the lowest concentration compared with other oils. So that, jojoba oil as using of carrier oil may be not harmful. And 3 essential oils from the fennel, tea tree and mamdarine may have very low toxicity, but cedarwood may be used carefully for inhalation. And over dosage of concentrated cedarwood oil should be not directly touched and exposured, and absolute essential oils must be diluted with carrier oils for topical and systematic massage.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.943-949
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• 1998

This study is concerned with the treatment of landfill leachate by carrier meditated emulsion. Using the batch operation, the optimum conditions for the removal of anionic and cationic materials were obtained. The landfill leachate from the plant was experimented under these conditions. The experimental variables were surfactant (Arlacel80) concentration and carrier(Aiquat336, DEHPA) concentration in membrane phase and counter ion concentration in internal phase. More than 80%(COD) of landfill leachate component could be removed within 12 minutes. The most crucial experimental variable for the removal efficiency was carrier concentration in membrane phase. In the other variables, the reaction time was more effected than the removal efficiency.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.6
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• pp.61-69
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• 2000

Indium-Tin Oxide (ITO) films were prepared on the commercial glass substrate by the Magnetron Sputtering method. The target was a 90wt.% $In_2O_3$-10wt.% $SnO_2$with 99.99% purity. The ITO films deposited by changing the partial pressure of oxygen gas ($O_2$/(Ar+$O_2$)) of 2, 3 and 5% as well as by changing the substrate temperature of $300^{\circ}C$ or $500^{\circ}C$. The influence of substrate pre-annealing and pre-cleaning on the quality of ITO film were examined, in which the substrate temperature was $500^{\circ}C$ and oxygen partial pressure was 3%. The characteristics of films were examined by the 4-point probe, Hall effect measurement system, SEM, AFM, Spectrophotometer, and X-ray diffraction. The optimum ITO films have been obtained when the substrate temperature is $500^{\circ}C$ and oxygen partial pressure is 3%. At optimum condition, the film showed transmittance of 81%, sheet resistivity of $226\Omegatextrm{cm}^2$, resistivity($\rho$) of $5.4\times10^{-3}\Omega$cm, carrier concentration of $1.0\times10^{19}cm^{-3}$, and carrier mobility of $150textrm{cm}^2$Vsec. From XRD spectrum, c(222) plane was dominant in the case of substrate temperature at $300^{\circ}C$, without regarding to oxygen partial pressure. However, in the case of substrate temperature at $500^{\circ}C$, c(400) plane was grown together with c(222) plane, only for oxygen partial pressure of 2 and 3%. In both case of chemical and ultrasonic cleaning without pre-annealing the substrate, it showed much almost same sheet resistivity, resistivity($\rho$), transmittance, carrier concentration, and carrier mobility. In case of $500^{\circ}C$/60min pre-annealing before ITO film deposited, both transimittance and carrier mobility are better than no pre-annealing, because pre-annealing is supposed to remove alkari ions diffusion from substrate. ITO film deposited on the Corning 0080 sybstrate showed a little bit better sheet resistivity, resistivity($\rho$), transimittance, carrier concentration than the film deposited on commercial glass. But no differences between Corning substrate and pre-annealed commercial glass substrate are found.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2720-2724
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• 2007

Field measurements have revealed that the pressure drop over a borehole during drilling of a slim oil well or a well with a long reach can depend significantly on the rotation speed of the drill pipe. An accurate prediction of the annular frictional pressure drop is therefore important for conditions where the annular clearance is small. An experimental study was carried out to study solid-liquid two phase flow in a slim hole annulus. Annular velocities of carrier fluids varied from 0.2 m/s to 1.5 m/s. The carrier fluids which were utilized included tap water and CMC water solutions. Pressure drops and average flow rates were measured for the parameters such as inner-pipe rotary speed, carrier fluid velocity, hole inclination and particle injection rate. For both water and CMC solutions, the higher the concentration of the solid particles is, the larger the pressure gradients become.

• Korean Journal of Materials Research
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• v.14 no.1
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• pp.41-45
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• 2004

P-type $Bi_{0.5}$$Sb_{1.5}$ $Te_3$ thin films were deposited by the flash evaporation technique, and their thermoelectric properties and electronic transport parameters were investigated. The effective mean free path model was adopted to examine the thickness effect on the thermoelectric properties. Annealing effects on the carrier concentration and mobility were also studied, and their variations were analyzed in conjunction with the antisite defects. Seebeck coefficient and electrical resistivity versus inverse thickness showed a linear relationship, and the effective mean free path was found to be 3150$\AA$. No phase transformation and composition change were observed after annealing treatment, but carrier mobility increased due to grain growth. Carrier concentration decreased considerably due to reduction of the antisite defects, so that electrical conductivity decreased and Seebeck coefficient increased. When annealed at 473 K for 1 hr, Seebeck coefficient and electrical conductivity were $160\mu$V/K and 610 $W^{-1}$ $cm^{ -1}$, respectively. Therefore, the thermoelectric quality factor were also enhanced to be $16\mu$W/cm $K^2$.>.

• Korean Journal of Materials Research
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• v.27 no.8
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• pp.438-444
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• 2017

In this work, the effects of hydrogen reduction on the microstructure and thermoelectric properties of $(GeTe)_{0.85}(AgSbTe_2)_{0.15}$ (TAGS-85) were studied by a combination of gas atomization and spark plasma sintering. The crystal structure and microstructure of TAGS-85 were characterized by X-ray diffraction(XRD) and scanning electron microscopy (SEM). The oxygen content of both powders and bulk samples were found to decrease with increasing reduction temperature. The grain size gradually increased with increasing reduction temperature due to adhesion of fine grains in a temperature range of 350 to $450^{\circ}C$. The electrical resistivity was found to increase with reduction temperature due to a decrease in carrier concentration. The Seebeck coefficient decreased with increasing reduction temperature and was in good agreement with the carrier concentration and carrier mobility. The maximum power factor, $3.3{\times}10^{-3}W/mK^2$, was measured for the non-reduction bulk TAGS-85 at $450^{\circ}C$.

• Elastomers and Composites
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• v.23 no.1
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• pp.11-17
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• 1988

The transport of chromium(VI) ion from waste water through the liquid surfactant membrane containing tri-n-octylamine as a carrier, was analyzed by a slab model and was investigated through experiments. For the experiment of membrane stability, concentrations of surfactant and liquid paraffin oil were analyzed. Extraction experiments were carried out to observe the effect of system variables, such as concentrations of carrier, and initial chromium(VI) ion in external aqueous phase at $25^{\circ}C$. It is concluded that the most stable formation of liquid membrane emulsion was obtained when surfactant concentration is above 3 wt.% and liquid paraffin oil concentration is 50 vol.%. The theoretical equation on the transport of chromium(VI) ion agreed well with the experimental results.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.107-107
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• 2011

오늘 날 transparent conductive oxide는 다양한 분야에서 활용되고 있다. 최근에는 태양전지 분야에서도 많이 활용되고 있으며, 초기에는 transmittance 및 낮은 sheet resistance 특성을 가지는 ITO가 많이 활용되었지만 thin film solar cell와 같이 hydrogenation 공정에 약한 ITO보다는 Al-doped ZnO가 사용되기 시작하면서 많은 연구가 진행되고 있다. 본 연구에서는 thin film solar cell 및 silicon heterojunction solar cell에 적용 가능한 Al-doped ZnO에 관한 연구로써 a-Si:H의 Si-H bonds에 영향을 주지 않는 낮은 영역의 substrate temperature와 power로 Al-doped ZnO를 형성하고 상기 parameter에 따른 Al-doped ZnO의 특성 변화에 대해서 분석하였다. 특히 substrate temperature가 변화할수록 carrier concentration 및 sheet resistance가 많은 변화를 보였으며 이로 인하여 transmittance 특성이 온도에 따라 좋아지다가 너무 높은 온도에서는 오히려 좋지 않게 되었다. 이는 너무 높은 carrier concentration은 free carrier absorption에 의해 transmittance 특성을 오히려 좋지 않게 한다. 우리는 본 연구를 통해 92.677% (450 nm), 90.309% (545 nm), 94.333% (800 nm)의 transmittance를 얻을 수 있었다.

• Analytical Science and Technology
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• v.12 no.3
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• pp.224-229
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• 1999

Recently, many studies for the supported liquid membrane (SLM) using a carrier have been actively reported. Polymeric cation exchange membrane was synthsized by dissolving monensin carrier of antibiotic material in organic solvent. Then the SLM was applied to the Nernst-Planck and Fick equations and membrane potential and membrane permeability were measured respectively. The results showed the high selectivity towards alkali metal ions and the SLM showed linear relationship with low concentration. However, linear relationship did not appear at high concentration. This is explained by means of the new theory of the stagnant layer and the slop of logarithm value was linear for the up-hill transport phenomena of membrane transport.

• Korean Journal of Materials Research
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• v.16 no.8
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• pp.490-496
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• 2006

ITO monolayer and ITO/Ag/ITO multilayer thin films are prepared by D.C. magnetron sputtering method. Ag layer was inserted for applying ITO to a flexible substrate at low temperature. Carrier concentration and carrier mobility of ITO and ITO/Ag/ITO thin films were measured, the transmittance of them also was done. The amorphous phase was confirmed to be combined in addition to (400) and (440) peaks from XRD result of ITO thin film. As the substrate temperature increased, the preferred orientation of (400) appeared. From the result of application of Ag layer at room temperature, the growth of columnar structure was inhibited, and the amorphous phase formed mostly. The ITO/Ag/ITO thin film represented the transmittance of above 80% when the thickness of Ag layer was 50 ${\AA}$, and the concentration of carrier increased up to above 10 times than that of ITO thin film. Finally, since very low resistance of 3.9${\Omega}/{\square}$ was observed, the effective application of low temperature process is expected to be possible for ITO thin film.