• 한국연초학회지
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• 제22권2호
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• pp.143-150
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• 2000

This study was carried out to investigate the effect of storage period on the physico-chemical properties of tobacco leaves expanded by $CO_2$. The flue-cured and burley tobacco leaves produced from 1996 to 1999 were processed, and stored for that year or 3 years in processing plant. As compared with 1996 crop, the expanded rate of flue-cured tobacco leaves in 1999 crop was higher approximately 18%, while that of burley was higher about 10%. The filling capacity of cigarettes was decreased as storage time became shorter, but the combustibility was improved. The rate of large particles (over 3.36mm) of expanded tobacco showed decreasing tendency as the storage period became longer. The change rate of chemical contents in tobacco leaves between before and after expansion had no significant difference among corp years. The tar and CO contents of cigarettes smoke were reduced in the case of flue-cured tobacco leaves as storage time became shorter, while they were slightly increased in the case of burley tobacco leaves. The ammonia content of burley leaves was decreased remarkably in 1996 and 1999 crop.

• 한국식품위생안전성학회지
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• 제6권1호
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• pp.49-56
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• 1991

인삼 엽록차의 위생화를 위한 화학 훈증제 처리 및 감마선 조사가 시료의 몇가지 이화학적 특성에 미치는 영향을 조사하였다. 녹차의 품질에 관련된 가용성분, 사포닌 및 탄닌성분은 상업적 조건 ethylene oxide 처리와 10kGy 까지의 감마선 조사에 대하여 안정하였다. 그러나 비타민 C 및 클로로필은 5kGy 이상 조사와 훈증 처리시에 유의적으로 감소되었고, 녹차의 휘발성 성분, 추출액의 색도 및 pH는 살균선량 범위인 5kGy 조사군에 비해 훈증처리군에서 변화가 심하게 나타났다 .

• 한국환경복원기술학회지
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• 제4권4호
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• pp.12-18
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• 2001

This study was carried out to analyze physico-chemical properties of soils at the ground of landscape planting in reclaimed land from the sea on Kwangyang Bay, South Korea. Physico-chemical properties of soils at each planting grounds were tested by ANOVA and were significantly(P<0.01) different. The difference came from the soil properties of the covered soil, the disturbance applied to the soil with land use and the accumulation of organic matter after landscape planting. Soil hardness, pH, ECe, Na and K level were in a stable condition at high then low of ground height for landscape planting. Organic matter accumulation was greater at lower planting grounds then top and slope ground of big mounding. The planting grounds of favorable growth for landscape trees were determined as following order : the slope ground and the top ground of big mounding>the ground of medium mounding>the coved ground of improve soil>the lower ground of big mounding>the filled ground of improve soil.

• Environmental Analysis Health and Toxicology
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• 제23권3호
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• pp.143-164
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• 2008

Concern about perfluorinated compounds (PFCs) is growing nationally as well as globally. PFCs could be considered emerging POPs due to their environmentally persistent, bioaccumulative, and potentially harmful properties. Moreover. perfluoroalkylates (PFAs) such as PFOS and PFOA are reported to experience long-range transport (LRT) to the Arctic in spite of their low volatility and strong solubility. The possible pathways contributing to LRT have been proposed but are still in debate in combination with unclear source definition and uncertain physico-chemical properties. The environmental fate of PFCs is more complicated because of the presence of precursors that are degraded to PFAs and are extremely different from their daughters, PFAs. in physico-chemical properties. To what extent and through what pathways are human and wildlife exposed is determined by the environmental fate and distribution of PFCs. To define uncertainties in fate and distribution thus is critical to prevent erroneous policy and/or determination related with exposure and risk reduction. This article aimed to review controversy and/or uncertain issues for the environmental fate and distribution of PFCs and to prospect research topics necessary to dissolve uncertainties.

• 한국식품위생안전성학회지
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• 제6권3호
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• pp.165-169
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• 1991

염장미역 제품의 염농도 감소와 저장 조건 개선을 위한 연구의 일환으로 감마선 조사가 염장미역의 이화학적 특성에 미치는 영향을 조사한 결과는 다음과 같다. 미역의 chlorophyll과 carotenoid 색소는 감선 조사에 의해 부분적으로 감소되었고 $10^{\circ}C$ 내외의 저장조건에서 6개원 저장시 비조사 시료와 2kGy 조사시료의 색소 잔존률은 서리 유의적인 차이가 없이 chlorophyll이 47~77%, carotenoid가 54~56%였다. 미역의 관능적 품질과 관련된 유기산과 휘발산의 함량은 염농도가 낮고 저장온도가 높을수록 증가하였고, 감마선 조사에 의한 미역의 조직 연화는 알긴산 추출과 관련이 있는 것으로 나타났다.

• 한국산업보건학회지
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• 제24권2호
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• pp.238-245
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• 2014

Objectives: It was known that workers in synthetic leather company are mainly co-exposed to dimethylformamide(DMF) with methyl ethyl ketone(MEK) or toluene(TOL) instead of a single dimethylformamide. This study was examined to the physico-chemical properties in single DMF and binary mixture DMF with MEK or TOL. Materials: Physico-chemical properties were measured by Korean and American Standard Test Methods. Results: Boiling point, specific gravity and flash point in single DMF were significantly higher than binary mixture DMF with MEK or TOL and such difference was dependent on the mixing ratio of MEK and TOL, and low explosion limit in binary mixture DMF with TOL was only significantly lower than single DMF. However, Reid vapor pressure had significantly higher in binary mixture DMF with MEK or TOL compared with single DMF. Conclusions: Our results demonstrate that the binary mixture DMF with MEK or TOL synergistically increases volatilization of DMF. It was concluded that the interaction between DMF and MEK and/or TOL might play a key role in the volatilization process of DMF under environmental conditions of workplace.

• Journal of Ginseng Research
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• 제35권4호
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• pp.487-496
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• 2011

Good manufacturing practice (GMP)-based quality control is an integral component of the common technical document, a formal documentation process for applying a marketing authorization holder to those countries where ginseng is classified as a medicine. In addition, authentication of the physico-chemical properties of ginsenoside reference materials, and qualitative and quantitative batch analytical data based on validated analytical procedures are prerequisites for certifying GMP. Therefore, the aim of this study was to propose an authentication process for isolated ginsenosides $Rb_1$ and $Rg_1$ as reference materials (RM) and for these compounds to be designated as RMs for ginseng preparations throughout the world. Ginsenoside $Rb_1$ and $Rg_1$ were isolated by Diaion HP-20 adsorption chromatography, silica gel flash chromatography, recrystallization, and preparative HPLC. HPLC fractions corresponding to those two ginsenosides were recrystallized in appropriate solvents for the analysis of physico-chemical properties. Documentation of the isolated ginsenosides was made according to the method proposed by Gaedcke and Steinhoff. The ginsenosides were subjected to analyses of their general characteristics, identification, purity, content quantitation, and mass balance tests. The isolated ginsenosides were proven to be a single compound when analyzed by three different HPLC systems. Also, the water content was found to be 0.940% for $Rb_1$ and 0.485% for $Rg_1$, meaning that the net mass balance for ginsenoside $Rb_1$ and $Rg_1$ were 99.060% and 99.515%, respectively. From these results, we could assess and propose a full spectrum of physicochemical properties for the ginsenosides $Rb_1$ and $Rg_1$ as standard reference materials for GMP-based quality control.

• 한국식품과학회지
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• 제25권5호
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• pp.438-443
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• 1993

Physico-chemical properties of glucitol fatty acid polyesters (GPE)-one of the potential fat substitutes-were analyzed and compared with conventional edible oil. The refractive Index, apparent viscosity and melting point of S-GPE (soybean oil GPE) were 1.472, 103 cps. at $37^{circ}C\;and\;-53^{\circ}C$, respectively. S-GPE were liquid at room teperature and the Yellowness of S-GPE was slightly stronger than that of soybean oil. The acid value and smoke point of S-GPE were 0.06 and $200^{\circ}C$. To supplement the weak thermal stability of S-PEG, SP-GPE (soybean-palm blended oil GPE) was prepared with soybeanpalm blended oil (70% of soybean oil and 30% of palm oil). The appearance and color of SP-GPE was not much different from S-GPE but the smoke point of that was increased to $210^{\circ}C$. It means that thermal stability of GPE can be enhanced by increasing saturation of the fatty acid composing GPE. Because most of physico-chemical properties of S-GPE or SP-GPE were similar to conventional edible oil, they are expected to be considered as a potential fat substitute with further study for confirming the safety.

• 한국토양비료학회지
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• 제30권1호
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• pp.67-71
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• 1997

농경지의 정밀토양조사(精密土壤調査) 결과를 이용하여 토양유형(土壤類型), 지형(地形) 및 층위별(層位別)로 토양의 물리, 화학적 특성을 분석 검토한 결과는 다음과 같다. 1. 점토함량(粘土含量)을 유형별로 보면 A층에는 사질밭과 보통밭에서 낮았고 중점(重粘)밭에서 가장 높았으며 B층에서는 화산회밭이 높았다. 토층간에는 화산회밭을 제외하고는 B층이 A층보다 낮았다. 2. 유기물함량(有機物含量)은 다른 유형의 밭에 비하여 화산회밭과 고원(高原)밭에서 현저히 높았다. 3. 양이온치환용량은 사질밭, 보통밭과 미숙(未熟)밭에서 낮았으며 고원밭의 A층도 $13.2cmol^+/kg$으로 높은 편이었고 화산회밭은 가장 높았다. 4. 보통(普通)밭 B층의 물리 화학적 특성간에는 높은 상관관계가 인정되었으며 양이온치환용량은 유효수분(有效水分), 점토, 미사 및 유기물함량과 정(正)의 상관(相關)관계를 보였다.

• 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.