• 대한의생명과학회지
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• 제23권4호
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• pp.388-394
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• 2017

Recently, coffee is the most popular beverage for modern people. A great number of substances are found in coffee beans and have been studied for many years such as aliphatic and aromatic compounds. However, studies on the physiological activity of coffee extracts are insufficient. This study was performed to determine the contents of caffeine and chlorogenic acid in coffee extracts according to the solvent and to investigate the physiological activity of coffee extracts. Coffee extracts were extracted by ultrasonication method with various types of solvents including distilled water, ethanol, and other organic solvents under $50^{\circ}C$ and $80^{\circ}C$. The contents of caffeine and chlorogenic acid in coffee extracts were determined by Liquid Chromatography-Mass Spectrometry (LC-MS). Also, cytotoxic and antioxidative effects of coffee extracts were evaluated with MTT and DPPH assays to analyze the physiological activity. As a result, it was confirmed that caffeine and chlorogenic acid contents were extracted in distilled water with the highest rate. Antioxidative activity was observed below 10-fold dilute of coffee extracts, however cytotoxicity was not observed. In conclusion, distilled water was the best solvent for extracting caffeine and chlorogenic acids from coffee bean with ultrasonication and these coffee extracts are less cytotoxic in human skin cell lines and have antioxidant effect.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1841-1846
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• 2000

To examine the effect of acid fog on the corrosion fatigue behavior in structural steel, fatigue tests under acid fog atmosphere were carried out in comparison with distilled water. The corrosive c omponents contained in acid fog pile up the corrosion products on crack face and show a crack branching and crack tip blunting. Therefore, due to these workings crack growth rate was reduced by decreasing the effective stress range in crack tip rather than under distilled water. Also the effect of sulfuric acid, which is the main component of acid fog, and testing speed on fatigue crack growth were examined. It was found that corrosion behavior was remarkably dependent upon pH and Hz rather than components of acid fog. According as pH and testing speed decrease below a specific value, crack growth was accelerated in comparison with distilled water. This reveals that due to liquid having strong acidity and slow speed of test the crack face dissolution was promoted, so crack closure was disturbed in the process of stress descent.

• 대한치과기공학회지
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• 제23권1호
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• pp.115-121
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• 2001

This study was investigated on effect of implant system about investment condition and burn out temperature. Posterior bridges were fabricated by using plastic sleeve and gold sylinder. The results were as follows; In plastic sleeve test and fitting cast copings. the phosphate bonded investment showed better gypsum bonded investment. The pure special liquid showed better margin fitness compared with mixed liquid (special liquid + distilled water). In gold cylinder test. the good burn out temperature of Ceramic PFG and Crown Gold was evaluated $0^{\circ}C$ to $820^{\circ}C$ and was decreased on $780^{\circ}C$ for 30 minutes. $0^{\circ}C$ to $750^{\circ}C$ and was decreased on $650^{\circ}C$ for 30 minutes.

• Food Science and Biotechnology
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• 제14권3호
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• pp.334-339
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• 2005

An instrument using thermal probe method was designed to measure thermal conductivity of liquid and solid foods. Thermal conductivity probe was designed with diameter to length ratio of 100 and diameter of 0.51 mm to minimize axial flow effect on thermal conductivity measurement. Thermal conductivities of distilled/deionized water, glycerin, and beef frankfurter meat were measured at $20-80^{\circ}C$. Mean thermal conductivity values of water showed less than 2.0% difference from several reference values without using time correction factor or probe calibration constant. For glycerin, difference was less than 0.7% from reference values at $20-50^{\circ}C$. Mean values of thermal conductivity for beef frankfurter meat ranged from 0.389 to $0.350\;W/m{\cdot}K$ at $20-80^{\circ}C$.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.277.1-277.1
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• 2003

A high-performance liquid chromatographic method using the liquid extraction procedure was developed for the determination of L -FMAUS. a new L -FMAU derivative, in rat plasma and urine using 3-aminophenyl sulfone as an internal standard. A 100-${\mu}\ell$ aliquot of distilled water containing the L -cysteine (100 mg/$m\ell$) was added to a 100-${\mu}\ell$ aliquot of biological sample. L-Cysteine was employed to protect binding between 5'-thiol of l and protein in the biological sample. (omitted)

• 대한치과보철학회지
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• 제9권1호
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• pp.41-45
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• 1969

A major disadvantage of Dental cements is their solubility. So it is very important to measure the exact amount of solubility to select clinically suitable materials. The most common laboratory test for solubility is the measurement of disintegration in distilled water, as outlined in A.D.A. Specifications 8 and 9, In addition to the possible factors influencing the solubility, the experiments were all conducted in compliance with A.D.A. Specifications. The solubility of 2 Zinc Phosphate cements and 1 Silicate cement in time of dissolution, concentration of solute in dissolving medium, and type of dissolving medium were investigated. The following results were obtained. 1. Generally the materials were more soluble in organic acids than in distilled water. 2. The dissolution cements tends be minimized by tests utilizing prolonged storage in the same media. 3. In Acetic acid solution, Zinc Phosphate cements were more soluble than Silicate cement, and in Citric acid solution both were markedly more soluble. 4. Solubility was increased by continually presenting fresh liquid, unsaturated with solute, to the cement-water interface.

• 전기학회논문지
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• 제59권7호
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• pp.1272-1275
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• 2010

The Cu powder was prepared in distilled water. It has a wide range of size distribution. The submicron-sized particles in the Cu powder were removed by using continuous type centrifugal separator. The average particle size after classification was approximately 50nm. The XRD analysis showed that pure Cu phase and oxide phase ($Cu_2O$)weremixedinthepowderpreparedbythismethod.

• 한국엔터테인먼트산업학회논문지
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• 제14권7호
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• pp.589-597
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• 2020

본 연구는 천연물질인 증류 죽초액이 함유된 천연화장품의 여드름 피부 개선에 대한 효과성을 검증하여 여드름 화장품 소재 개발을 목적으로 하였다. 연구의 대상 10대 남·여 20명을 선정하여 난수표방식에 따라 10명은 천연화장품(폼 클렌징, 토너, 팩)을 사용한 대조군으로 10명은 증류 죽초액이 함유된 천연화장품(폼 클렌징, 토너, 팩) 사용한 실험군으로 배정하였다. 화장품 사용 기간은 12주로 하였고, Mark-·Vu 피부 측정기를 사용하여 사전, 6주 후, 12주 후 피부의 피지, 모공 크기, 붉은기를 측정하였다. 수집된 자료는 SPSS v. 21.0 통계 패키지 프로그램을 활용하여 분석하였으며, 결과는 다음과 같다. 첫째, 천연화장품의 피부 안정성 확인을 위한 인체첩포시험 결과 피부에 안전한 제품으로 확인되었다. 둘째, 대조군과 실험군의 피지, 모공 크기, 붉은기에 대한 동질성 검증 결과 동질성이 확보되었다. 셋째, 증류 죽초액이 함유된 천연화장품의 여드름 피부 개선 효과 검증에서 실험군이 대조군에 비해 이마와 오른 볼 부위의 피지, 모공 크기, 붉은기 변화의 감소율이 더 크게 나타났다. 이에 증류 죽초액이 함유된 천연화장품은 피부에 안전하며, 여드름 피부에서 피부의 피지 감소와 모공 크기 및 붉은기 감소에 효과적인 것으로 확인됨에 따라 화장품 산업에서 증류 죽초액 활용을 기대하는 바이다.

• 한국산학기술학회논문지
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• 제19권8호
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• pp.403-409
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• 2018

고온 부품 소재로 사용하는 니켈계 내열합금인 Inconel 713C에는 Ni 70 %, Cr 12 %, Al 6 % 및 Mo 4% 등의 유가금속을 함유되어 있다. 이중 유가금속에서 경제적 가치를 가지는 원소는 Mo이므로 회수하여 재활용하여야 한다. 본 연구는 폐 인코넬계(Inconel 713C) 모의 내열합금 침출액으로부터 액-액 추출법(용매추출법 및 역추출법)을 이용하여 Mo을 분리 회수하였다. 회수된 수상을 증발 건조 및 열처리법을 이용하여 Mo 화합물을 제조하였다. 수상은 $NaMoO_4$ $2H_2O$을 증류수에 용해하여 사용하였으며, 추출제로는 음이온추출제인 Alamine 336과 양이온추출제인 Cyanex 272, 희석제로는 등유(Kerosene) 사용하였고, 음이온추출제인 Alamine 336 1 %이상에서 99 % 이상의 추출률을 확인하였다. 역추출제로는 황산, 염산 및 질산을 사용하였고, 각각 농도가 증가할수록 탈거율이 증가하였으며, 질산의 경우 4 M에서 96 %의 탈거율을 나타냈었다. 용매추출과 역추출에서 얻은 Mo 함유 수상을 증발 건조하여 순도 97.5 %의 $MoO_3$를 제조하였다. 본 연구를 통해 Mo이 함유된 순환자원으로부터 Mo을 효율적으로 회수하면 국내의 자원효율성과 자원수요의 공급경쟁력을 향상시킬 수 있다.

• 한국전기전자재료학회논문지
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• 제23권9호
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• pp.736-740
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• 2010

Nickel wires of 0.8 mm in diameter and 80 mm in length were electrically exploded in liquid media such as water, ethyl alcohol. The distribution of particle sizes was broad from a few micrometers to tens of nanometer. It was identified that the particles could be classified according to its sizes by using centrifugal separator. The powder prepared in distilled water showed mainly pure metallic Ni phase although a little oxide phase was observed. The powders prepared in ethyl alcohol showed complicated unknown phases, which is attributed to the compound of carbon in the organic liquid. This unknown phase was turned to pure metallic Ni phase after heat treatment.