• Journal of Biosystems Engineering
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• 제38권4호
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• pp.295-305
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• 2013

Purpose: Recent research showed that total mixed ration (TMR) feeding for pigs improved the productivity and reduced feed cost and manure odor. An automatic TMR feeding system was developed for this study because the conventional feeder cannot deliver the TMR containing roughage. Methods: Conventional feeding systems and physical properties of TMR were surveyed, and performance tests of the conventional feeder were conducted to develop a TMR feeder. Based on the TMR feeder was developed and installed, driving, measuring weight, radio frequency identification (RFID) reading, and discharging test for feeding were conducted to ensure the performance. Results: Moisture content, density, and angle of repose of the TMR 1 (mixture of 30% cut IRG silage and 70% concentrates) were 31.6%, 387 $kg/m^3$, and $51^{\circ}$, respectively. Moisture content, density, and angle of repose of the TMR 2 (mixture of 45% concentrates, 30% cut IRG silage and by-products, 10% bean curd refuse, 10% others, and 5% fermenter) were 22.2%, 544 $kg/m^3$, and $50^{\circ}$, respectively. The coefficient of variation (C.V.) of conventional concentrate feeding were 1.9~4.1%, and C.V. of TMR containing 1~3% cut IRG roughage feeding by conventional feeder were 9~42%. The conventional disc type feeder was not suitable for TMR feeding because the supply unit was clogged. The C.V. of TMR 1 was 0.6~7.9% when 0.5~10 kg of the TMR supplied, and it was suitable for feeding grow-finish pigs and sows. On the contrary, the C.V. with TMR 2 was 28% when 0.5 kg of the TMR supplied, and it was not suitable for feeding sows. Conclusions: The TMR feeder developed in this study was suitable for feeding grow-finish pigs because the feeder performed stably with over 5.0 kg feed. However, the feeder showed a lack of accuracy for feeding sows because the amount of each feed was more than 0.5 kg per a feeding. Therefore, the improvement of outlet structure for accurate feeding is needed for sow feeding.

• Journal of Microbiology and Biotechnology
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• 제12권5호
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• pp.740-745
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• 2002

The current study was conducted to identify the differences in the rheological properties of Chlorella sp. powder cultured in a fermentor and in a pond-like environment. Cells. cultured in the same media were harvested and spray dried. The biomass yield from the fermentor culture was 4.7% (dry basis), while that from the pond was 4.3% (dry basis). Measurements of the loose bulk density, tapping test, Hausner's ratio, and compressibility test all revealed differences between the rheological properties of the Chlorella sp. from the two cultivation systems. Although both the fermentor and pond cultured Chlorella sp. showed the same angle of repose, the mean size of the cells was 2.26 $\mu\textrm{m}$ and 2.89 $\mu\textrm{m}$, respectively. The weight of the Chlorella sp. tablets cultured in the fermentor and pond was 0.663 g/tablet and 0.593 g/tablet, respectively, while the friability of the tablets was 21% and 41%, respectively. Observation by Transmission Electron Microscope (TEM) showed that the cell wall of the Chlorella sp. cultured in the fermentor was thinner and more spherical than that cultured in the pond, thereby providing the main characteristic rheological properties of the powder.

• Journal of Pharmaceutical Investigation
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• 제40권6호
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• pp.347-351
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• 2010

Isoflavones have received much attention because of their health-related and clinical benefits such as estrogenic and anti-oxidative activities as well as triggering of natural killer cell activity. However, there are few publications reporting the pharmacokinetic profiles together with physicochemical properties of main isoflavones. Therefore, the pharmacokinetic parameters of main aglycones, daidzein, glycitein and genistein after oral administration of soybean extracts were investigated and the physicochemical properties of soybean extracts were characterized. It was observed that angle of repose was $46^{\circ}$ and tap density, bulk density and porosity were 10.12, 4.3 and $0.86\;g/cm^3$ and the mean $AUC_{last}$ of daidzein, glycitein and genistein was $11.376\;{\mu}g{\cdot}h/mL$, $3.045\;{\mu}g{\cdot}h/mL$ and $0.825\;{\mu}g{\cdot}h/mL$, respectively. Cell viability was 60% at a concentration of 10 mg/mL. Taken together, it was suggested that isoflavones were contained in the soybean products and had an antioxidant activity and this study would be the basis to control the quality of soybean products and study of the bioequivalence between soybean products in future.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1750-1754
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• 2010

구조물 주변의 국부세굴에 대한 예측은 현장관측 및 수리실험 결과를 이용한 다양한 경험식과 수리모형 실험, 수치 모의 등을 통하여 이루어진다. 본 연구에서는 최근 국내에서 많이 사용되고 있는 3차원 수치모형인 FLOW-3D의 세굴분석 능력 검토를 제고하기 위하여 민감도 분석을 실시하였다. FLOW 3D의 입력 매개변수는 평균입경(Average particle diameter), 유사 비중(Density of the sediment particle), 한계 무차원 소류력(Critical Shields number), 세굴 조절개수(Scour erosion adjustment), 한계 유사비(Critical sediment fraction), 점착성 유사비(Cohesive sediment fraction), 유사 항력(sediment drag force), 안식각(Angle of repose)이 있다. 이 중에서 평균입경, 안식각, 세굴조절개수, 한계 유사 fraction 등의 매개변수에 대해 초기값을 중심으로 일정 비율로 구분하여 민감도 분석을 실시하였다. 주요 매개변수의 민감도 분석 결과는 수리실험 결과치와 비교 검토 후에 민감도의 변화 범위와 선행하여 조정할 수 있는 매개변수를 제시할 수 있다. 이러한 결과를 바탕으로 수공구조물 주변의 국부 세굴에 관한 해석시 FLOW-3D를 이용한 분석에서 보다 신뢰도 높은 결과 산출이 가능할 것으로 판단된다.

• 한국재료학회지
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• 제29권7호
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• pp.425-431
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• 2019

Generally, ceramic tiles for building construction are manufactured by dry forming process using granular powders prepared by spray drying process after mixing and grinding of mineral raw materials. In recent years, as the demand for large ceramic tiles with natural texture has increased, the development of granule powders with high packing ratio and excellent flowability has become more important. In this study, ceramic tile granule powders are coated with hydrophobically treated silica nanoparticles. The effects of hydrophobic silica coating on the flowability of granule powders and the strength of the green body are investigated in detail. Silica nanoparticles are hydrophobically treated with GPTMS(3-glycidoxypropyl trimethoxy silane), which is an epoxy-based silane coupling agent. As the coating concentration increases, the angle of repose and the compressibility decrease. The tap density and flowability index increase after silica coating treatment. These results indicate that hydrophobic treatment can improve the flowability of the granular powder, and prevent cracking of green body at high pressure molding.

• 농업과학연구
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• 제47권4호
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• pp.717-726
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• 2020

The physical characteristics of the major varieties of perilla were analyzed to use as basic data for the design of a high-quality, high-efficiency perilla cleaner and stone separator. Because the size, thousand-grain weight, angle of repose, angle of friction, bulk density and terminal velocity of perilla have significant differences according to the perilla variety, the different of characteristics by variety should be considered for performance improvement of a perilla cleaner and stone separator. Therefore the cleaner and stone separator using a sieve could be improved by the application of a detachable sieve or by using equipment such as a 2 - 3 stage sieve and regulating the slope. Moreover, because differences in the terminal velocity occur due to the differences in the size and thousand-grain weight according to the perilla variety, a blower with an adjustable fan speed was considered for the design of the improved cleaner. Additionally, it was shown that the length of perilla has the greatest correlation based on a comparison of the coefficients of the other characteristics. Accordingly, the length of perilla could be used as a major factor for the fine adjustment and parts replacement of the device. These results can be used as basic data for a high-quality, high-efficiency perilla cleaner and stone separator. In the future, the development of the machine and follow-up studies based on the basic data are needed to determine the optimized operating conditions and mechanism of action.

• 공업화학
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• 제24권2호
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• pp.126-131
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• 2013

메이크업 화장품 원료로 사용되는 일라이트 분체에 피부 친화성을 부여하고 다양한 특성을 개선하고자 분체 표면에 BGsome 코팅을 시도하였다. BGsome은 1,3-부칠렌 글리콜에 용해된 레시틴을 수화시키는 과정을 통하여 만들어지는 수화 액정형 베시클이다. BGsome 베시클 입자를 습식방법으로 분체 표면에 코팅시키고 TGA, SEM, 입자크기 측정기 등을 사용하여 코팅된 분체를 분석하였다. BGsome 코팅에 의한 유동성, 분산도, 발림성, 부착성 등과 같은 여러 물성의 변화도 살펴보았다. 코팅된 일라이트의 유동성이 개선됨은 안식각 감소 결과로부터 알 수 있고 기타 분산도, 발림성, 부착성 등도 크게 개선됨을 확인하였다. 부착성 테스트 결과에서 코팅된 일라이트가 인조가죽 위에 뭉침이 없이 고르게 퍼지는 현상을 볼 수가 있었다. 코팅된 일라이트를 함유하는 페이스 파우더 또한 유동성, 분산도, 발림성, 부착성 등이 모두 개선된 결과를 나타내었다.

• Applied Biological Chemistry
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• 제36권6호
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• pp.416-423
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• 1993

건조방법 및 원료성분을 달리하여 분유를 제조하고 이들분유의 몇 가지 리올로지 특성을 Instron Universal Testing Machine으로 측정하여 얻어진 결과는 다음과 같다. 드럼건조된 전지분유의 부피밀도는 $0.382\;g/cm^3$으로 탈지 및 조제 분유보다 높았고, 분무 건조된 탈지 분유의 Hausner ratio, 평정각 및 compressibility 는 각각 1.127, $32.5^{\circ}$, 0.029로 탈지 분유는 자유롭게 흐르는 것을 보여주었으며, 드럼건조된 전지분유의 compressibility는 수분 함량이 4.96%에서 3.89%로 감소함에 따라 0.079에서 0.052로 낮아졌다. 전지분유 그래뉼의 compressibility는 0.056으로서 분유의 compressibility보다 낮았다. 분무 건조된 분유는 구형으로서, 동결건조나 드럼건조된 분유보다 더 견고함을 나타냈다.

• 한국수자원학회논문집
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• 제43권10호
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• pp.921-932
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• 2010

본 연구는 하천의 골재채취 혹은 하천준설로 인하여 교란된 하천의 적응과정을 하도의 평면변화에 적합하도록 일반좌표계 상에서 흐름 및 하상변동을 모의할 수 있는 2차원 수치모형을 이용하여 파악하였다. 수치해석 기법으로는 흐름의 운동량 방정식에서 이류항은 CIP (Cubic Interpolated Pseudoparticle)법을 적용하였으며, 확산항은 중앙차분법을 적용하였다. 하천준설 혹은 골재채취에 의해 형성된 웅덩이는 초기에 웅덩이 상류 지점에서 급격한 두부침식이 발생하였다. 시간이 증가하면서 웅덩이는 상류에서 공급되는 유사에 의하여 되메워지고, 일정한 안식각을 유지하면서 거의 균일한 속도로 이동하였다. 웅덩이 하류에서는 하상저하가 지속되고 있다. 수치모의 결과는 이러한 과정을 잘 모의하였다. 하상경사가 급할 경우에, 웅덩이의 변화에 대하여 되메워지는 시간이 짧고, 웅덩이의 이동속도가 빠른 것을 보여주고 있으며, 수치모의 결과는 실내실험 결과에 잘 일치하였다.

• Journal of Electrochemical Science and Technology
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• 제11권1호
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• pp.60-67
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• 2020

In this study, copper (II) oxide powder for electroplating was prepared by recovering CuCl₂ from NaClO₃ type etching wastes via recovered non-sintering two step chemical reaction. In case of alkali copper carbonate [mCuCo₃·nCu(OH)₂], first reaction product, CuCo₃ is produced more than Cu(OH)₂ when the reaction molar ratio of sodium carbonate is low, since m is larger than n. As the reaction molar ratio of sodium carbonate increased, m is larger than n and Cu(OH)₂ was produced more than CuCO₃. In the case of m has same values as n, the optimum reaction mole ratio was 1.44 at the reaction temperature of 80℃ based on the theoretical copper content of 57.5 wt. %. The optimum amount of sodium hydroxide was 120 g at 80℃ for production of copper (II) oxide prepared by using basic copper carbonate product of first reaction. At this time, the yield of copper (II) oxide was 96.6 wt.%. Also, the chloride ion concentration was 9.7 mg/L. The properties of produced copper (II) oxide such as mean particle size, dissolution time for sulfuric acid, and repose angle were 19.5 mm, 64 second, and 34.8°, respectively. As a result of the hole filling test, it was found that the copper oxide (II) prepared with 120 g of sodium hydroxide, the optimum amount of basic hydroxide for copper carbonate, has a hole filling of 11.0 mm, which satisfies the general hole filling management range of 15 mm or less.