• 한국지하수토양환경학회지:지하수토양환경
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• 제6권4호
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• pp.61-72
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• 2001

폐기물 매립장에는 발생되는 침출수의 유출을 방지하기 위하여 매립장의 바닥 또는 측면에 투수계수가 1x$10^{7}$cm/sec이하인 차수재를 설치한다. 본 연구는 폐기물 매립장 차수재인 토양-벤토나이트 차수재 (혼합토)를 대상으로 하여 현장토의 토성에 따른 벤토나이트의 배합비와 투수계수의 특성을 파악하고 벤토나이트의 팽윤도 및 다짐방법이 차수층의 투수특성에 미치는 영향을 파악하였다. 연구결과 동일조건에서 최대건조밀도는 SC계열의 혼합토가 CL계열의 혼합토보다 높게 나타났고, 최적함수비는 그 반대의 경향을 나타냈으며, 다짐방법별로는 최대건조밀도의 경우 D다짐시가 높게 나타났고, 최적함수비는 A다짐시의 경우가 높게 나타났다. 다짐에너지에 따른 최대건조밀도의 차이는 SC계열의 혼합토가 더 큰 것으로 나타났고, 최적함수비의 경우는 CL계열의 혼합토가 더 큰 차이를 보이는 것으로 나타났으며 팽윤도에 따른 최대건조밀도 및 최적함수비의 차이는 미미하였다. 벤토나이트의 배합비 및 팽윤도가 증가함에 따라 투수계수는 낮은 값을 나타내었고 동일조건에서는 CL계열의 혼합토와 D다짐시 낮은 투수계수를 나타내었다. 그러나 투수계수는 팽윤도보다는 벤토나이트의 배합량에 의해 더 많은 영향을 받는 것으로 나타났고 동일조건에서 SC계열의 혼합토와 A다짐시 더 큰 차이를 나타내었다. 투수시험결과에 따른 시공시 경제성을 검토한 결과 팽윤도가 낮은 벤토나이트를 배합한 경우가 더 경제적인 것으로 나타났는데 이는 팽윤도별 재료단가의 큰 차이에 비해 투수계수 감소효과가 기대에 미치지 못하기 때문인 것으로 판단된다.

• 한국농공학회지
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• 제17권2호
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• pp.3778-3783
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• 1975

The objective of this study is to determine an appropriate cement of soil-cement in which silty soil of salty tidal flat with low plasticity was used. Physical, chemical and mechanical tests were conducted to find out the standard properties of the soil to be used. Various cement contents used in this test were 8%, 10%, 12%, and 14%, and the compressive strength was tested after 7 days and 28 days of standard curing in the above each cement content respectively. The results obtaind are summarized as follows. 1. As the cement content was increased from 8% to 14%, Maximum dry density (M.D.D.) and optimum moisture content (O.M.C.) were not changed remarkably. 2. Density of soil-cement was directly proportional to cement content and inversely proportional to water content. 3. OMC was generally decreased in proportion to the increase of cement content. 4. Compressive stranth was directly proportional to centent and inversely proportional to water content. 5. In freezing and thawing test, maximum loss of 10% in the total Weight was found on the 8% cement mixture. and This loss was rapidly decreased to 2% when the Cement content of the mixture was more than 10%.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.417-430
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• 2003

A new method was developed to prepare microcapsules involving hydrophobic components. A totally new "silicone-resin-polypeptide" was used as the wall materials. The polypeptide was made by hydrolysis of collagen and silk protein and so on, and that was combined with silicone. This microcapsule was easily prepared from silicone-resin-polypeptide in water solution. The ratio of encapsulation in the microcapsule was not only high level as 90％, which had never been reached, but also the particle size could be controlled to obtain very small size (average particle size: 2${\mu}{\textrm}{m}$). Moreover, these microcapsules were resistant to high shearing forces and were stable over a long time period. This stable microcapsule was not crushed in pressure with finger spreading, so the core materials hardly touch the skin directly. Application in cosmetics by using microcapsule involving UV absorbents (2-ethylhexy1-4-methoxycinnamate (OMC) and 4-tert-butyl-4' -methoxydibenzoyl-methane (BMDBM)) was examined. It was possible to apply organic UV absorbents in water-rich formulations without any surfactant by using this microcapsule. This formulation demonstrated a good moisturizing and soft skin feel. Therefore, the microcapsule was applied to hair care products. As a result, the sunscreen hair lotion with microcapsule was able to prevent from damaging and decoloring of hair color by UV rays. As just, it was suggested that this microcapsules were be widely applied in cosmetics.cosmetics.

• 천문학회보
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• 제41권2호
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• pp.55.5-56
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• 2016

Turbulence plays an important role in molecular clouds. However, the properties of turbulence are poorly understood. In order to study the influence of turbulence in molecular clouds, we need to sample the turbulent properties in the full range of scales down to sonic scale. We mapped the $20^{\prime}{\times}60^{\prime}$ area covering the Orion Molecular Cloud (OMC) 1-4 region in HCN 1-0 and HCO+ 1-0 with Taeduk Radio Astronomy Observatory (TRAO) 14-m telescope as part of the TRAO key science program, "Mapping turbulent properties of star-forming molecular clouds down to the sonic scale (PI: Jeong-Eun Lee)". In addition, we combine our TRAO data with other molecular line maps ($^{13}CO$ 1-0, $C^{18}O$ 1-0, CS 1-0, $N_2H^+$ 1-0) obtained with the Nobeyama Radio Observatory (NRO) 45-m telescope. To analyze these data, we apply statistical methods, the principal component analysis (PCA) and spectral correlation function (SCF), which are known to be useful to study underlying turbulent properties and to quantitatively characterize cloud structure. We will present the preliminary results of observations and analyses.

• 천문학회보
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• 제42권2호
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• pp.79.3-80
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• 2017

Molecular clouds are the sites of stellar birth. Turbulence is a natural phenomenon in molecular clouds, which largely determines the density and velocity fields. Additionally turbulent energy dissipation can affect the gas kinetic temperature via shocks. Turbulence thus controls the mode and tempo of star formation. However, despite its important role in star formation, the properties of turbulence remain poorly understood. As part of the Taeduk Radio Astronomy Observatory (TRAO) Key Science Program (KSP), "Mapping turbulent properties of star-forming molecular clouds down to the sonic scale (PI: Jeong-Eun Lee)", we have been mapping two star-forming clouds, the Orion A and the ${\rho}$ Ophiuchus molecular clouds in 3 sets of lines (13CO 1-0/C18O 1-0, HCN 1-0/HCO+ 1-0, and CS 2-1/N2H+ 1-0) using the TRAO 14-m telescope. We apply a Principal Component Analysis (PCA), which is an useful tool to represent turbulent power spectrum. We will present the preliminary results of our TRAO KSP toward two regions: OMC 1-4 in the Orion A cloud, and L1688 in the ${\rho}$ Ophiuchus cloud.

• Environmental Engineering Research
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• 제12권1호
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• pp.1-7
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• 2007

Most of the herb residue producing from oriental medical clinics(OMC) and hospitals(OMH) is wasted in Korea. To develop of adsorbent for removing heavy metal from wastewater, the various pre-treatment methods of the herb residue were evaluated by potentiometric titration, Freundlich isotherm adsorption test and the kinetic adsorption test. The herb residue was pre-treated for increasing the adsorption capacity by cleaning with distilled water, 0.1 N HCl and 0.1 N NaOH and by heating at $370^{\circ}C$ for 30 min. It showed a typical weak acid-weak base titration curve and a short pH break like commercial activated carbon during photentiometric titration of pre-treated herb residue. The log-log plots in the Freundlich isotherm test were linear on the herb residue pre-treated with NaOH or HCl like commercial activated carbon. The adsorption capacity(qe) in the Freundlich isotherm test for $Cr^{6+}$ was 1.5 times higher in the pre-treated herb residue with HCl than in activated carbon. On the other hand the herb residue pre-treated with NaOH showed the good adsorption capacities for $Pb^{2+}$, $Cu^{2+}$ and $Cd^{2+}$ even though those adsorption capacities were lower than that of activated carbon. In kinetic test, most of heavy metals removed within the first 10 min of contact and then approached to equilibrium with increasing contact time. The removal rate of heavy metals increased with an increase of the amount of adsorbent. Likewise, the removal rates of heavy metals were higher in the herb residue pre-treated with NaOH than in that pre-treated with HCl. The adsorption preference of herb residues pre-treated with NaOH or HCl was $Pb^{2+}>Cu^{2+}$ or $Cd^{2+}>Cr^{6+}$ in the order. Conclusively, the herb residue can be used as an alternative adsorbent for the removal of heavy metals depending on pr-treatment methods.

• Journal of Chest Surgery
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• 제22권6호
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• pp.1025-1035
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• 1989

Since we first performed open heart surgery on December 30, 1986, 126 cases were operated on up to August 31, 1989. Among the 126 cases, 65 cases were congenital heart disease of which 63 were acyanotic disease, and 61 cases were acquired heart disease, most of which were valvular heart disease. The age distribution of congenital heart disease was from 1 years 2 months to 48 years, and males had a slightly higher incidence. The age of acquired heart disease was from a minimum of 15 years to a maximum of 68 years, and the male to female ratio was 1;1.5. Midsternotomy was performed in all cases, and the aortic cannula was inserted through ascending aorta and the venous cannula inserted into the SVC and IVC through the right atrium. Vent was inserted through the right superior pulmonary vein. Cardioplegia solution was used in all cases; it was composed of sodium bicarbonate 3.5 ampule, KCL 14 mEq, 2% lidocaine 2.5 ml, 20 % albumin 50 ml and heparin 1000 units mixed to 950 ml with Hartman solution, and was made to 4oC and infused 10 ml per Kg every 20 minutes. The congenital heart disease had a variety of VSD in 32 cases, ASD 23 cases, PS 6 cases, PDA 2 cases, and one case each of Ebsteins anomaly and tricuspid atresia. The operations performed for acquired heart disease were 4 cases of OMC, 33 cases of MVR, and 5 cases of AVR, and 1 case of AVR with CABG. DVR was perfomed in 13 cases, and triple valve replacement was done in 1 case. Other than these, excision of LA myxoma was 2 cases, and repair of traumatic VSD and removal of a pulmonary embolism were one case each. The surgical mortality was 5 cases[4%], all of which occurred in valve replacement cases. Follow-up study revealed 2 late deaths. One died after a traffic accident and one died due to sepsis after he had received a gastrectomy for ulcer bleeding. The remaining patients were in good condition.

• Korea Journal of Cosmetic Science
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• 제2권1호
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• pp.1-10
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• 2020

Protection mechanisms for skin damage of ultraviolet (UV) absorbers in personal care products for protection against UV are well studied, but not for hair protection. The purpose of this study is to describe and compare the changes of physical property produced in human hair by doses of the UV-B exposure causing protein degradation. To observe the change of physical properties in hair, the experimental intensity of UV-B exposure has been established on the basis of statistical data from official meterological administration as daily one hour sunlight exposure for two weeks. Polysilicone-15, ethylhexyl methoxycinnamate (OMC), and octocrylene were employed for UV-B absorber, and those were treated to hair swatch by rubbing wash through shampoo and conditioner. Bending rigidity displayed kinetically successive reduction at high doses of UV exposure up to the 8,000 s, and exhibited different level at each sample of UV-B absorber. However, the values of Bossa Nova Technologies (BNT) for shinning factor were already saturable at the 2,000 s exposure except that treated with polysilicone-15. The differential scanning calorimetry (DSC) to measure a strength of inner protein produces a successive reduction of enthalpy as like a reduction of bending rigidity upon UV exposure. Surface roughness from lateral force microscope (LFM) acquired immediately after UV exposure show a saturable frictional voltage which has been also found in a saturable BNT data as the time of UV exposure increases. Through researching the DSC and the LFM, shinning of hair was much correlated to the protein damage at the surface, and bending rigidity could be regulated by the protein structural damage inside hair. Therefore, the optimization of efficient strategy for simultaneous prevention of hair protein on the surface and internal hair was required to maintain physical properties against UV.

• 한국환경농학회지
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• 제42권3호
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• pp.253-258
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• 2023

In the environment, chromium often exists in a highly mobile and toxic form of Cr(VI). Therefore, the reduction of Cr(VI) to less toxic Cr(III) is considered an effective remediation strategy for Cr(VI)-contamination. In this study, the biological reduction of hexavalent chromium was examined at the concentrations of 0.01 mM, 0.1 mM, and 1 mM Cr(VI) by the dissimilatory metal-reducing bacterium, Shewanella sp. HN-41 in the presence of ferric-citrate. With the relatively condensed cell densities, the aqueous phase Cr(VI) was reduced at the proportions of 42%, 23%, and 31%, respectively for the 0.01 mM, 0.1 mM, and 1 mM Cr(VI) incubations, while Fe(III)-citrate was reduced at 95%, 88%, and 73%, respectively. Although the strain HN-41 was not considered to reduce Cr(VI) as the sole electron acceptor for anaerobic metabolism in the preliminary experiment, it has been presumed that outer-membrane c-type cytochromes such as MtrC and OmcA reduced Cr(VI) in the presence of ferric-citrate as the electron acceptor. Since this study indicated the potential of relatively high cell density for Cr(VI) reduction, it might propose a bioremediation strategy for Cr(VI) removal from contaminated waters using engineered systems such as bioreactors employing high cell growths.

• 한국대기환경학회지
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• 제31권4호
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• pp.319-329
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• 2015

The characteristics of aerosol light extinction were investigated by comparing measured and calculated extinction coefficient to understand the contribution of air pollutants on visibility impairment for data during 4 months (Jan~ April), 2014. The integrated nephelometer and aethalometer system were installed to measure the scattering and absorption coefficients of aerosol as well as BAM 1020, MARGA, semi-continuous OCEC analyzer, and online-XRF to calculate the extinction coefficient. The IMPROVE_2005 equation was used to determine the contributions of different chemical components on visibility impairment in $PM_{2.5}$ and $PM_{10}$ due to highest correlation with measured data. Sulfate, nitrate, and organic mass by carbon (OMC) of fine aerosol were the major contributors affecting on visibility impairment. Total contributions to light extinction were calculated as $631.0Mm^{-1}$ for the worst-case and $64.4Mm^{-1}$ for the best-case. The concentrations of aerosol component for the worst-case were 38.4 times and 45.5 times larger than those of the best-case for $(NH_4)_2SO_4$ and $NH_4NO_3$, respectively. At lower visibility condition, in which extinction coefficient was higher than $400Mm^{-1}$, extinction coefficient varied according to the relative humidity variation regardless of $PM_{2.5}$.