• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.883-888
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• 2001

We describe an ion-surface scattering apparatus newly developed to investigate the reactive scattering process of low-energy alkali-metal ions at surfaces. The apparatus consists of an alkali-metal ion gun that is rotatable by 360°, a quadrupole mass spectrometer (QMS) with an ion energy analyzer, a sample manipulator with a heating-and-cooling stage, and an ultrahigh vacuum (UHV) chamber that houses these components. Preliminary experimental results obtained from the apparatus are presented on angular and energy distributions of the ions scattered from clean Pt(111) and water-adsorbed Pt surfaces.

• 펄프종이기술
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• 제35권3호
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• pp.43-52
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• 2003

The new principle to measure a sizing degree by a contact angle was developed using an automatic determination of the 3-end point coordinates of the water droplet on a sheet, which could diminish the operator's bias during measurement. A constant amount of water was first placed on a sample sheet by a water dispenser, and then an image of the liquid droplet was captured by a digital camera and then transmitted to a computer. The program measuring for contact angle extracted a liquid contour by Gaussian function combined with a 8-direction chain code. The Euclidean equation was applied to the binary image of the liquid contour in order to measure the diameter of the contour. Finally, the contact angle of the liquid was calculated by using the diameter and the top coordinates. In addition, a surface free energy of the sample sheet and an elapsed time taken up to the complete absorption into the sheet were simultaneously measured with the contact angle.

• 한국전기전자재료학회논문지
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• 제13권12호
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• pp.983-988
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• 2000

The leadframe of thin plate fabricated by stamping method generates a lot of burr and stress in the processing surface because of the mold. The electropolishing equipment was produced in order to increase accuracy and surface roughness for 42%Ni-Fe leadframe. An electrolyte consisted of phosphoric acid, ethylene glycol and deionized water. Experiments were accomplished as polishing conditions were changed such as current density, polishing time, electrode gap and sample shape. The burr from the cutting was eliminated and surface characteristics of high flatness and high luster wre obtained after electropolishing. In addition, the electroplishing had good characteristic in 1.0 A current density and 4㎜ of electrode spaces, and it was affected by the composition of electrolyte and the sample shape.

• 한국식품영양과학회지
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• 제26권6호
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• pp.1013-1020
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• 1997

To elicit the effect of fermentation on food quality of the watery Chinese cabbage pickles without fish sauce and red pepper paste(Baik-kimchi), changes in physicochemical properties and microstructure of fiber components were studied. Better water holding capacity(WHC) was showed in Baik-kimchi fermented at $25^{\circ}C$ than that of Baik-kimchi fermented at 5$^{\circ}C$. WHC measured at pH 2 and 6 were ranged from 10.18 to 16.79g/g dried sample for Baik-kimchi fermented at $25^{\circ}C$ and 6.51~14.58g/g dried sample for sample for samples at 5$^{\circ}C$, respectively. The higher WHC was resulted in pH controlled freeze-dried sample to pH 6 than that measured in pH 2 sample. The settling volume(SV) and oil adsorption capacity(OAC) increased with fermentation period and kept the same value for a little while, but slightly decreased in the over ripening period. Baik-kimchi fermented at $25^{\circ}C$ exhibited more shrunk microstructure of parenchyma cell and xylem than those of Baik-kimchi fermented at 5$^{\circ}C$. The appearance of SDF of the both Baik-kimchi ripened at 5$^{\circ}C$ and $25^{\circ}C$ could give granular shape, whereas the overripened Baik-kimchi had smooth surface of SDF. On the other hand, the IDF retained the original shape during fermentation.

• 한국식품영양과학회지
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• 제33권6호
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• pp.1068-1073
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• 2004

노루궁뎅이 버섯의 열수 추출 실험을 실시하면서 반응표면분석에 의해 추출물의 특성을 최적화하였다. 추출물의 가용성 고형분은 설정된 추출온도와 추출시간에 대해서는 영향을 받지 않는 것으로 나타났으며, 용매에 대한 시료비가 증가할수록 가용성 고형분이 증가하였으며, 페놀성 화합물과 조단백 함량도 추출온도보다는 용매에 대한 시료비가 더 큰 영향을 미치는 것으로 나타났다. 추출물의 전자공여작용은 용매에 대한 시료비와 추출온도가 증가할수록 증가하다가 최적 추출조건에서 최대점을 보이다가 이후로 감소하는 경향을 나타내었다. 이들 추출물의 특성을 모두 만족시키는 최적 추출조건은 추출온도 91.5$^{\circ}C$∼96.5$^{\circ}C$, 용매에 대한 시료비 3.5∼4.2 g/100 mL로 나타났으며 예측된 최적 추출조건의 임의의 점에서 실험한 결과, 각 반응변수들의 예측값과 실제값이 유사하였다.

• 한국식품조리과학회지
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• 제23권1호통권97호
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• pp.1-8
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• 2007

Extraction conditions were optimized using response surface methodology for preparing high-quality, hot water extracts from cultivated Chrysanthemum indicum L. petals. A fractional factorial design was applied to investigate the effects of added sample ratio ($X_1$), extraction temperature ($X_2$) and extraction time ($X_3$) variables on extract properties, such as, soluble solid contents ($Y_1$), sugar content ($Y_2$), ?E ($Y_3$), turbidity ($Y_4$), total phenol ($Y_5$) and DPPH ($Y_6$). Second-order models were employed to generate a 3-dimensional response surface for dependent variables and their coefficients of determination ($R^2$) ranged from 0.8408${\sim}$0.9914. The range of optimum conditions at $80^{\circ}C$ extraction for maximize characteristics of hot water extracts was 2.3${\sim}$2.7 g and 9.2${\sim}$11.2 hr.

• 한국응용과학기술학회지
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• 제37권5호
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• pp.1248-1256
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• 2020

In this study, the polyurethane resin was synthesized by applying PTMG and DMBA of different composition ratios for the synthesis of water-dispersible polyurethane used in wound coating resin. The varying properties of the synthesized water-dispersible polyurethane were measured through tensile strength, elongation, and abrasion resistance analysis. As for the tensile strength measurement result according to the PTMG content, the sample with the highest reaction molar ratio was measured as 1.08 kgf/mm2 and the elongation was measured as 520%. As for the tensile strength result according to the DMBA content, the sample with the highest reaction molar ratio was measured as 0.51 kgf/mm2, and the elongation was measured as 435%. The degree of surface destruction by the abrasion resistance measurement was visually confirmed through SEM.

• 대한환경공학회지
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• 제35권6호
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• pp.442-448
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• 2013

물속의 색도 측정방법에는 비색법과 분광학적방법이 있다. 비색법은 농도가 알려진 백금-코발트 표준용액과 시료의 색을 비교하여 색도를 측정하는 방법이며 분광학적 색도 측정방법은 단일 또는 다중파장을 선택하여 색도를 측정하는 방법이다. 그러나 비색법의 경우, 분석자의 시력에 의한 단순 비교를 통해 색도를 측정하는 방법으로 측정결과의 신뢰성과 재현성이 우수하지 못할 뿐만 아니라 5 TCU 이하의 색도 측정이 불가능하다. 분광학적 색도 측정방법 중 단일파장법은 주로 색도 성분이 천연유기물질(휴믹물질)인 지표수나 지하수에만 적용이 가능한 것으로 나타났으며 하수와 같이 인위적인 화학적 색도 성분이 함유될 경우 색도 측정이 불가능하였다. 다중파장법은 지표수, 하수 등 다양한 시료에 대해 우수한 색도 측정결과를 나타냈으나 1개의 시료에 대해 수십 번의 측정과 복잡한 계산으로 실제 현장 적용에 어려움이 있었다. 따라서 본 연구에서는 지표수, 정수, 하수 등 다양한 시료에 대해 신속하고 정확한 색도 측정방법을 비교하였다. 그 결과, 다중파장 프로그램이 내장되어 3~4초 이내에 지표수, 하수 등 다양한 시료에 대해 신속하고 정확하게 색도 측정이 가능한 색도계 색도 측정방법이 가장 적합한 것으로 나타났다.

• Toxicological Research
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• 제17권
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• pp.319-321
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• 2001

Taihu Lake is a major water source for part of Yangtze Delta, which is one of the most urbanized and economically prosperous areas in China. In last couple of decades, some parts of the lake were highly polluted due to eutrophication. This study analyzed dioxin-like potential and mutagenic potential in surface water samples from Taihu Lake. The samples were prepared by XAD-2 resin procedure. A batch of biological assays, including dioxin-like potential microassay with the rat hepatocyte cell line H411E, and Ames test was employed in the research. Results showed that jour water samples have high content of dioxin-like biological potential, the highest activity TEQ to 2,3,7,8-TCDD was 48 pg/ι in sample 1. The mutagenic effect with reading-frame shifting mechanism was confirmed in 3 of 4 samples. The effective sewage treatment facilities and reliable monitoring surveillance system are urgently needed for this area.

• 한국정밀공학회지
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• 제34권1호
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• pp.59-63
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• 2017

We present a multi-sample array device based on a pneumatic system. Solenoid valves were used to control a micro valve in a pneumatic system. The use of a compressor together with a vacuum pump ensured that one outlet could supply both compression and vacuum pressure. The multi-sample array device was fabricated using conventional photolithography and PDMS casting. The device was composed of a multiplexer, sample array, and rinsing. The multiplexer could control four sample solutions injecting into the sample array chamber. Sample solution not arrayed was removed by DI-water from the rinsing inlet. To prevent trapping of microbubbles in the channel during injection of sample solution into the device, surfactant was added in PDMS solution to serve as a hydrophilic surface treatment. As a result, the device could be used as a sample array for 64 cases, using four samples and three columns of three chambers.