• Journal of Ginseng Research
• /
• v.10 no.1
• /
• pp.80-93
• /
• 1986

The tail portion of dried 6-year old white ginseng was extracted and sugars and nitrogen compounds were also evaluated for chemical properties depending on varying conditions of extractions. The factors studied were extraction temperature in the range of 70-$100^{\circ}C$, ethanol concentration of 0-90% and the times of extractions which was taken 8 hours per each extraction in water at $80^{\circ}C$. For the effect of ethanol concentration in the extraction solvent, it was found that the amounts of free, reducing and total sugars and starch recovered in extract were almost linearly decreased along with the increase of concentration and the nonprotein nitrogen accounted over 84% of total nitrogen in extract. As ethanol concentration became increased, extractions of total nitrogen and water souluble nonprotein nitrogen were decreased especially in 90% ethanol. For the extraction temperature, all the sugar fractions with water and 70% ethanol except free sugar have tended to increase along with the temperature raised from 70 to $100^{\circ}C$ and it was found there is little changes of nitrogen compounds in the temperature range except a rapidly increase in water soulble protein at $100^{\circ}C$. For the times of extractions, showed that most of extractable compounds were extracted in 3 times of extractions with water at $80^{\circ}C$. It was shown that more than 95f) of sugars and 80% of nitrogen compounds were yielded with water extraction. Accordingly it was efficient to extract with water or 70% ethanol in 3 times in terms of !actor and energy consumption.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.12 no.1
• /
• pp.7-12
• /
• 2006

The EU regulation of overall migration which is the cornerstone of the limitation to ensure that plastic materials and articles intended to contact with foodstuffs are fit for the intended application, was reviewed. In Council Directives, it was established in detail what simulants, contact times and temperatures are to be used in migration tests performed under standardized conditions. In some cases, conventional conditions for substitution test was provided, because of technical reasons. Moreover, a reduction factor ranging from 2$\sim$5 may be applied depending on the foods, because olive oil which is simulant for fatty foods, is severe solvent compared with most fatty food.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.184-184
• /
• 1994

개와 흰쥐의 장간막동맥 절편의 긴장도와 $^{86}$Rb$^{+}$ 유출에 대한 cromakalim의 효과를 관찰하고 이를 ATP를 고갈시킨 조직에서 얻어지는 결과와 비교하였다. Cromakalim은 개와 흰쥐의 장간막 동맥을 이완시켰으며, 이러한 이완은 glibenclamide에 의하여 상경적으로 억제되었다. Glibenclamide는 phenylephriue에 의한 개와 흰쥐의 장간막 동맥 수축을 증가시킨다든지 혹은 cromakalim에 의한 억제성 반응을 역전시켰다. 개와 흰쥐 장간막 등맥의 $^{55}$Rb$^{+}$ 유출 실험에서 tromakalim (10 $\mu$M) 투여시 ATP를 고갈시킨 흰쥐의 장간막 동맥에서 현저히 증가하였다. HPLC를 이용하여 adenine nucleotide를 분석하였다. Adenine nucleotide의 HPLC 분석시에 혈관의 내피세포를 제거하였고 0.2 M ammonium phosphate (pH 5.5)를 용출용매로 이용하여 분석하였다.

• Applied Biological Chemistry
• /
• v.36 no.1
• /
• pp.17-22
• /
• 1993

Effects of temperature, time, solvent addition ratio and number of extraction on contents of effectual components and soluble materials of cinnamon extracts were studied. All of the chemical contents of proximate composition and cinnamic acid, cinnamic aldehyde and eugenol were significantly increased as the extraction temperature increased from $20^{\circ}C$ to $80^{\circ}C$, while little change measured at $100^{\circ}C$. During ten hours of extraction at $80^{\circ}C$, more than six hours extraction showed a little increase effects the contents of cinnamic aldehyde, eugenol and proximate components. The ratio of solvents added to dried cinnamon also showed improving effects of chemical properties as the ratio increased from 5 to 40 times. Two times of extractions for 1 hour was found to be effective to recover those components.

• Korean Journal of Environmental Agriculture
• /
• v.21 no.2
• /
• pp.90-95
• /
• 2002

A study was carried out to optimize the cleanup step using a solid-phase extraction (SPE) cartridge, $SupelClean^{TM}$ Florisil, for multiresidue analysis of 16 pesticides in cucumber matrix. Eluting efficiencies of two solvent systems including acetone/n-hexane and ethyl acetate/n-hexane mixtures were critically evaluated by recoveries of target anaytes from the SPE Florisil column. Based on the recovery as a measure of eluting efficiency, an acetone/n-hexane (20/80,v/v) mixture provided more than 80% recovery for 15 pesticides except bifenthrin. In case of ethyl acetate/n-hexane, 14 pesticides showed recoveries higher than 75% while those far alachlor and bifenthrin were less than 30%.

• Journal of the Mineralogical Society of Korea
• /
• v.27 no.3
• /
• pp.115-124
• /
• 2014

In order to leach Au and Ag from gold-silver bearing sulfide concentrate, the sulfide concentrate was ground in a ball mill for a dry pre-treatment and a wet pre-treatment process. Mineralogical studies and thiourea leaching experiments were carried out with the pre-treated sulfide concentrate. The results of the pre-treatment with the concentrate samples showed the mean particle size and iso-electrical potential was smaller in the dry pre-treatment sample than in the concentrate sample, and the contents was lower in the wet pre-treatment sample than in the dry pre-treatment sample. In XRD analysis, amorphous properties were only shown in the wet pretreatment sample. The results of the concentrate sample leaching experiments showed that the best Au, Ag leaching parameters were when the addition of thiourea was at a 1.0 g concentration, ferric sulfate was 1.0 M, sulfuric acid was 2.0 M and the leaching temperature was at $60^{\circ}C$. The Au, Ag leaching rate was always much greater and faster with the wet pre-treatment samples than with the dry pre-treatment samples. Accordingly, it is expected that more Au, Ag can be leached in an eco-friendly methodology using wet pre-treatment. The pre-treatment could be improved with an optimized grinding additive reagent and through researching grinding time in future non-cyanide processes.

• Analytical Science and Technology
• /
• v.6 no.4
• /
• pp.383-390
• /
• 1993

Retention behaviors of aliphatic and aromatic compounds were investigated with Van der Waals volume which represented the molecular size. The organic solvents, methanol, acetonitrile and tetrahydrofuran, were mixed with water at various ratio, respectively. The selectivity of organic solvents were tested by change of column temperature. The capacity factor was increased linearly according to the enlargement of molecular size. Therefore, Van der Waals volume was useful to predict the elution of organic molecules in reversed-phase column. The order of elution capacity of solvents was methanol

• Economic and Environmental Geology
• /
• v.46 no.1
• /
• pp.21-28
• /
• 2013

In order to optimize gold leaching from refractory sulfide concentrate, a HCl-NaClO-$FeCl_3$ solution with varying attributes was applied to the roasted concentrate from Uil mine. The gold from Uil mine occurs in the form of invisible gold that is difficult to leach. The results of the gold leaching experiments showed that the best gold leaching parameters were $550^{\circ}C$ of roasting temperature, 2.0 M of concentration, 1.0% of pulp density, and $70^{\circ}C$ of leaching temperature. It is confirmed that the HCl-NaClO-$FeCl_3$ solution was an environmentally friendly method to leach gold and silver from the refractory sulfide concentrate as an alternative lixiviant to cyanide.

• Korean Journal of Medicinal Crop Science
• /
• v.16 no.5
• /
• pp.294-300
• /
• 2008

This study was performed to investigate the increasing of immune activities from Centella asiatica L. Urban by several solvent extraction with ultrasonification process. Ethanol extracts at $60^{\circ}C$ and associated with ultrasofication showed more 15% yield than normal $100^{\circ}C$ water extracts. And ethanol extracts showed higher yield than water extraction at each process. It can be concluded that yield due to polarity of compound in C. asiatica from HPLC peak. All of extracts from C. asiatica revealed lower cytotoxicity than 32%. The ethanol extracts with ultrasofication showed higher promotion on human B and T cell growth, about 10% compared to the control. The secretion of IL-6 and TNF-a was also enhanced as $4.86\;{\times}\;10^{-4}\;pg/cell$ and $5.73\;{\times}\;10^{-4}\;pg/cell$ each, by the addition ethanol extracts with ultrasonification to T cell. NK cell activation was improved up to 10% higher than the control, through adding the samples. It can be concluded that the ethanol extracts from C. asiatica has higher immune activities followed by ultrasonification process, possibly, by higher yield than conventional extraction process.

• Proceedings of the Korean Reliability Society Conference
• /
• 2006.05a
• /
• pp.239-246
• /
• 2006

프레스다이용 코일스프링은 자동차 및 전자제품의 외형생산에 필요한 금형 내에 장착되는 금형용 스프링으로서 녹아웃 및 스트리퍼 등에 사용되고 있다. 프레스다이용 코일스프링이 사용 중 파손 시에는 고가인 금형의 손상 및 생산성에 영향을 미칠 수도 있기 때문에 사용 환경에서의 신뢰성확보가 요구되어지고 있다. 특히 중(重)하중 및 극중(極重)하중용 스프링은 과거 현장에서 파손사례가 자주 발생함으로 인해 외산을 선호하는 경향이 있는 형편이다. 이에 국산 스프링의 신뢰성검증 및 확보를 위해 신뢰성기반구축사업을 통해 신뢰성평가기준(RS D 0014)가 제정되었으며, 이 평가기준에 의거하여 국내 업체의 제품에 대해 신뢰성평가를 실시하였다. 프레스다이용 코일스프링의 파손원인은 주로 반복하중에 의한 피로파손과 일정한 변위의 변형으로 발생하는 코일스프링 자유높이의 축소로 크게 구분되어질 수 있다. 시험결과 주 파손양상은 피로에 의한 균열발생이었으며, 코일 끝단부와 끝단부 직하부의 코일과의 마찰에 의한 균열발생이 주원인이었다. 즉, 코일의 끝단면과 직하면 코일이 연속적으로 부딪침으로써 발생한 변형 및 마모에 의해 표면균열이 발생하고, 표면균열에서 반복적인 부하하중이 가해짐으로써 피로균열 진전을 통해 점차적으로 파손이 진행되어졌음을 알 수 있었다. 본 발표에서는 기준에 의거하여 로하중용 프레스 다이용 코일스프링을 평가한 신뢰성평가시험 결과에 대해 보고하고, 파단면 관찰과 외산제품과의 미세조직 및 조성 등의 비교분석결과 등을 기초로 파손원인을 분석한 결과에 대해 보고하고자 한다.제고할 수 있을 것으로 기대한다.X>$CdCl^+,\;CdSO_4$ 등이 형성되었다. 수은의 경우는 해수 및 증류수를 용출용매로 이용한 모든 경우에서 납, 구리, 카드뮴과는 달리 대부분 침전하였다. 더욱이 해수에 존재하는 고농도 염소($Cl^-$)와의 수착으로 인해 finite solid인 calomel($Hg_2Cl_2$)이 형성되어 대부분 침전(SI=0)되기 때문에 납, 구리, 카드뮴 보다 더 낮은 환경이동성을 갖을 것으로 사료된다. 상기 실험결과 용출용매로 증류수와 해수를 이용했을 때, 제강 슬래그에서 용출되는 납, 구리, 카드뮴, 수은의 용출 경향의 차이를 확인할 수 있었고 이에 따라서, 납, 구리, 카드뮴의 용출 유해성은 낮기 때문에 해양구조물로의 제강슬래그 유효이용은 적합할 것으로 판단되었다.im80%$로 계산되었다. 열형광선량계로 측정된 방사선량은 각각 1.8, 1.2, 0.8, 1.2, 0.8 (70 cm 거리) cGy로 측정되었으며, 환자의 복부 표면에서의 서베이메터를 이용한 측정량은 10.9 mR/h였다. 차폐구조물의 사용 시 전체 치료 동안에 태아선량은 약 1 cGy 정도로 평가되었다. 결론 : AAPM Report No.50의 자료에 따르면, 임산부의 방사선 치료 시 태아의 방사선 피폭선량은 5 cGy 이하일 경우에 방사선 피폭에 따른 태아의 위험이 거의 없는 것으로 제시되고 있다. 본원에서 차폐 구조물을 설치하였을 경우에 측정된 태아선량은 약 1 cGy로 측정되었고, 고안된 차폐구조물