• Journal of Ecology and Environment
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• 제29권5호
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• pp.439-443
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• 2006

Soil properties of Quercus variabilis forest on Youngha valley at Mt. Worak National Park were studied as a part of Korea National Long-Term Ecological Research. Soil sampling was carried out along the 50 cm soil depth with 10cm intervals at every quarter from May 2005 through July 2006. Fresh soil was used for $NH_4{^+}-N,\;NO_3{^-}-N$, and soil water content determination. Remaining soils were air dried in the shade, and then used for determination of soil pH, T-N, T-P and exchangeable cation. Average soil organic matter in top soil was $8.5{\pm}1.2%$ and decreased with soil depth. Bulk density of top soil was $0.82{\pm}0.07g/cm^3 $and increased with soil depth. Soil organic matter and bulk density showed a negative linear correlation ($R^2=0.8464$). Soil pH in top soil and subsoil was similar. T-N, $NH_4{^+}-N,\;NO_3{^-}-N$ and T-P in top soil were $1.9{\pm}0.5mg/g,\;7.3{\pm}1.0mg/kg,\;2.0{\pm}0.4mg/kg\;and\;0.2{\pm}0.05mg/g$, respectively. $K^+,\;Ca^{2+}\;and\;Mg^{2+}$ in top soil were $84.6{\pm}24.4,\;408.8{\pm}137.8\;and\;93.4{\pm}23.0mg/kg$, respectively. They decreased with soil depth. Amounts of organic matter, T-N, $NH_4{^+}-N,\;NO_3{^-}-N$, T-P, $K^+,\;Ca^{2+}\;and\;Mg^{2+}$ in 50 cm soil depth were 250.9, 3.45, 0.025, 0.003, 0.639, 0.181, 0.845 and 0.302 ton $ha^{-1}\;50cm-depth^{-1}$, respectively.

• Archives of Pharmacal Research
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• 제29권5호
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• pp.424-429
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• 2006

In the present study, a human mammary epithelial cell (HMEC) culture model was developed to evaluate the potential involvement of carrier-mediated transport systems in drug transfer into milk. Trypsin-resistant HMECs were seeded on $Matrigel^{circledR}-coated$ filters to develop monolayers of functionally differentiated HMEC. Expression of the specific function of HMEC monolayers was dependent of the number of trypsin treatments. Among the monolayers with different numbers of treatment (treated 1 to 3 times), the monolayer treated 3 times (3-t-HMEC monolayer) showed the highest maximal transepithelial resistance and expression of $\beta-casein$ mRNA as an index of differentiation. Transport of tetraethylammonium (TEA) across the 3-t-HMEC monolayer in the basolateral-to-apical direction was significantly higher than that in the apical-to-basolateral direction (p<0.05), whereas such directionality was not observed for p-aminohippurate, suggesting the existence of organic cation transporters, but not organic anion transporters. In fact, expression of mRNAs of human organic cation transporter (OCT) 1 and 3 were detected in the 3-t-HMEC monolayer. These results indicate that the 3-t-HMEC monolayer is potentially useful for the evaluation of carrier-mediated secretion of drugs including organic cations into human milk.

• 자원리싸이클링
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• 제11권1호
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• pp.32-36
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• 2002

이 연구는 돈분, 석고와 석탄화를 혼합물을 퇴비화한 것이다. 실험에 사용한 A 시료(PM : SD = 6 : 4)와 C 시료(PM : SD : GS : CFA = 6 : 2 : 1 : 1)를 사용하여 퇴비화 실험결과 A, C 시료의 초기 수분함량은 64, 50%이었고 온도, pH에서도 A시료와 비교했을 때 큰 차이는 없었으나 A,C 시료의 최종 TOC는 약 5550, 2900 mg/kg 이었다. 양이온 교환능은 A, C시료와는 크게 차이는 없었으나 CEC값으로 보아 숙성에 더 많은 시간이 필요할 것으로 생각된다. 그러나 석고와 석탄회 첨가는 돈분 퇴비화 과정에서 첨가제로서의 역할이 있음을 알 수 있었다.

• 한국초지조사료학회지
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• 제11권1호
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• pp.22-29
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• 1991

This study was experimented to obtain the basic information on the changeable aspect and improvement of soil fertility in newly-reclaimed sloped land. Silage corn was cultivated under the six different treatments for 4 years. The relation between the amount or ratio of annual changes of soil physico-chemical properties and yield of silage corn were analyzed. Soil bulk density was decreased in 3rd year at topsoil, but that decreased in 4th year at subsoil. Soil organic matter also decreased in 2nd year at topsoil, and decreased continuously at subsoil. Bulk density and hardness of soil depths showed significant negative simple correlation with dry matter yield and cation exchange capacity showed positive. Correlation coefficient of chemical properties with dry matter yield were low. The range of annual changes of moisture percent, hardness and organic matter were wider than the other properties. The significantly different of physical properties were higher than the chemical properties, and those of topsoil were higher than subsoil. According to multiple regression between yield and physico-chemical properties of subsoil, bulk density and cation exchange capacity were in the greatest contribution at the variations, but bulk density was greatest at the ratios.

• 대한화학회지
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• 제30권4호
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• pp.359-368
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• 1986

Crown ether (DC18C6, DC24C8)과 HDEHP로 알칼리 금속 이온을 용매 추출할 때의 추출평형을 연구하였다. 추출평형상수는 DC18C6계에서 $Na^+순으로 증가하였으며 DC24C8계에서는 $Rb^+순으로 증가하였다. 유기용매상으로 추출되는 추출종은 $M_1(crown ether)_1\;(HDEHP)_1$이며 추출평형상수의 크기는 crown ether의 유기용매상과 수용액상에서의 분배비와 crown ether-알칼리금속 착물의 안정도 상수에 의해서 결정된다.

• 한국세라믹학회지
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• 제14권2호
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• pp.95-103
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• 1977

Characteristics of Ham Pyong clay and clay-organic complexes were investigated by means of geological exploration, chemical analysis, X-ray diffraction, differential thermal analysis, electron microscopy, thermal mechanical analysis, cation exchange capacity and viscosity measurement. The results are as follows; 1) This caly is a transported clay which has black and white colors, and the amounts of deposit are estimated about 1, 600, 000M/T. 2) The major mineral phases identified by X-ray diffraction are kaolinite, sericite and halloysite and the minor phases are quartz and feldspar, these mineral phases can be seperated very easily by the elutriation method. 3) It was supposed that the black colored clay involved a certain clay-organic complexs by the mechanism of intercalation as well as surface absorption. 4) The clay-organic complexes in clay seemed to improve dispersity, to increase the fluidity of clay-water slips, to decrease the firing shrinkage and to promote the thermo-chemical reaction at temperature range up to 50$0^{\circ}C$, but not to effect on the resulted firing color.

• 한국환경과학회지
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• 제8권1호
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• pp.69-74
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• 1999

Soil properties which affect the retention of Pb(I) were investigated in the laboratory. It was determined, through selective removal, that organic matter and Fe-oxides are of lesser importance in influencing Pb retention than are soil clay minerals. The following trend : clays ＞ organic matter ＞ Fe-oxides represents the relative importance of each constituent in the adsorption of Pb by soils. The consistently greater Pb uptake by surface over subsurface samples was apparently due to differences in organic matter content, inasmuch as organic matter removal from both resulted in similar adsorption characteristics. All five soils stooled exhibited a pH-dependent trend of adsorption. The extent of Pb adsorption was least at low pH values(4~5), was maximum in the neutral pH range, and leveled off or diminished under more alkaline conditions. There was no strong correlation between Pb uptake and soil cation exchange capacity as routinely measured by the NH$_4$OAc method. A knowledge of clay mineralogy in conjunction with soil pH is suggested as being the most reliable guide to predicting Pb retention by soils.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1588-1592
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• 2009

Lithium cyanoaluminum hydride (LCAH) was prepared by the metal cation exchange reaction of sodium cyanoaluminum hydride with lithium chloride in tetrahydrofuran. The reducing characteristics of LCAH were explored systematically by the reaction with selected organic compounds containing representative functional groups under the standardized conditions (tetrahydrofuran, 0 ${^{\circ}C}$). The reducing ability of LCAH was also compared with of the sodium derivative, sodium cyanoaluminum hydride (SCAH). Generally, the reducing behavior of LCAH resembles that of SCAH closely, but the reactivity of LCAH toward representative organic functional groups appeared to be stronger than that of SCAH. Thus, the regent reduces carbonyl compounds, epoxides, amides, nitriles, disulfides, carboxylic acids and their acyl derivatives to the corresponding alcohols or amines, at a relatively faster rate than that of SCAH. The cyano substitution, a strong election-withdrawing group, diminishes the reducing power of the parent metal aluminum hydrides and hence effects the alteration of their reducing characteristics.

• Current Research on Agriculture and Life Sciences
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• 제23권
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• pp.53-60
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• 2005

본 연구는 경주남산의 산림토양의 이화학적 특성을 분석하여 산림의 다목적이용과 남산의 산림보호 관리에 도움을 주고자 실시하였다. 조사지는 각 층위별로 토양성분을 분석하였고, 그 결과는 다음과 같다. 남산 산림토양의 물리적 특성은 토심이 31.4cm 이고 유효토심은 20.0cm 였으며 유기물층의 깊이는 5.9cm였다. 계곡부를 제외한 다른 조사지의 토성은 사질 양토이었다. 전체 토양 pH는 평균 4.76으로 우리나라 산림토양의 평균보다 낮게 나타났으며 유효인산의 함량은 평균 3.64로 유효인산의 함량이 매우 적은 것으로 나타났다. 치환성양이온($Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$)의 함량은 우리나라 산림토양의 함량과 보다 낮은 수치를 나타내었으며 특히 $Ca^{2+}$함량은 우리나라 산림토양의 평균 $2.44cmol_c/kg$보다 낮은 함량인 $1.04cmol_c/kg$를 나타내었다.

• 한국응용과학기술학회지
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• 제22권3호
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• pp.219-227
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• 2005

Competitive solvent extraction of the mixure of alkali metal and alkaline earth cation from water into organic solvent containing the crown ether carboxylic acid and anlogous crown ether phosphonic acid was investigated as follows. The lipophilic group is found to strongly influence to the selective extraction in the mixed systems from only alkali metal cation for sym-(n-decyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ to mostly alkaline earth metal cation for sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid $\underline{3}$. Monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{2}$. and monoethyl-sym- bis]4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{4}$ showed good selectivity for $Na^+$ over $Mg^{2+}$, the second extracted ion. Structural variation in the crown ether phosphonic acid somewhat was influenced to the extraction selectivity in the mixed systems. when variation of the ionized group is influenced in the mixed systems, the selectivity of $Na^+$ as the second extracted ion was much better crown ether carboxylic acid $\underline{1}$ than crown ether phosphonic acid $\underline{2}$, while the efficiency of $Na^+$ extraction was better $\underline{2}$ (83% total loading) than $\underline{1}$ (32%).