• YAKHAK HOEJI
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• v.38 no.1
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• pp.38-45
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• 1994

An analytical method using capillary electrophoresis (CE) was developed for quantitation of water soluble vitamin contents in various vitamin products. The method includes the optimization of separation of 11 water soluble vitamins changing the micellar concentration and pH of running buffer, applied voltage and sample preparation. Best resolution was obtained with 25 mM phosphate buffer (pH=8.0) containing 50 mM sodium dodecyl sulphate (SDS) as micellar phase. At optimum condition, water soluble vitamins were determined in orange juice and vitamin products such as vitamin C pulvis, vitamin injection, coated multivitamin tablet. The quantitative analysis of water soluble vitamins with CE was suitable for quality control of pharmaceutical products with sound reproducibility.

• Journal of the Korean Ceramic Society
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• v.12 no.2
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• pp.26-30
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• 1975

The experiment has been carried out to clarify the condition of acid treatment for preventing the crack formation caused by swelling and shrinking during acid leaching process. The borosilicate glass contained phosphorous pentoxide was chosen as the sample, which is recognized to be more homogeneous in phase separation. The various effects, such as kind, cocentration and acid temperature, were investigated. The experimental results are summerized as follows. (1) Sulfuric acid is more stable than hydrochrolic acid for preventing the crack. (2) The optimum concentration of acid lies in the range of 0.1~0.3N. (3) Higher temperature of the acid to treat the separated glass was more stable than lower temperature. (4) The rate of crack decreased with the longer period and the higher temperature of the heat treatment.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.267-270
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• 2003

Oleanolic acid is a triterpenoid compound that exists in Oldenlandia diffusa. Recently, oleanolic acid has been noted for antitumor effect. Application of both plant growth regulators, 2,4-D and kinetin, was found to be essential for the induction of callus and suspension cells. Optimum induction condition for callus and suspension cells of Oldenlandia diffusa was determined to be 0.5 mg/L 2,4-D and 0.1 mg/L kinetin. Chromatographic separation of oleanolic acid from its derivatives was achieved using Rexchrom S5-100-ODS column. The retention time of oleanolic acid was 12.6 min and the specific content of oleanolic acid was 0.41 mg/g dry weight.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.239-242
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• 2004

Pilot-scale soil washing facility was developed and operation condition was determined in order to remediate a soil contaminated with As, Ni and Zn. Soil washing facility is composed of soil particle separation, soil washing and wastewater treatment process. Both oxyanionic As and cationic Ni and Zn were effciently removed using HCl rather 0than H$_2$SO$_4$ and H$_2$PO$_4$. This is why oxyanion and cation metals can be extracted simultaneously from the contaminated soil in acidic solution. Further, the contaminated soils include calcite and then demand much acidity, that is consumption of acid solution. Fine particles are enriched with contaminants, and coarse particles are removed effectively rather than fine particles. As, Ni and Zn are strongly associated with minerals, and then the residence time should be increased for a reaction with washing solution.

• Journal of the Korean Wood Science and Technology
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• v.15 no.4
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• pp.12-17
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• 1987

To extract arabinogalactan from larch (Larix Leptolepis), chips immersed with water(20-$90^{\circ}C$) for 1hr, were defiberized by refiner. The liquors were recovered and purified to pure arabinogalactan by ion exchange resin(IRC-50 a. IR-45) or MgO. Additionally the optimal condition in purification with MgO was also investigated. 1. The amounts of solids(crude sugars) and pure arabinogalctan in solids are 8.6-11.3% and 7.3-8.5%(raw material = 100), respectively. 2. Phenolic materials in crude sugars are removed up to 96-89% by ion exchange resin and 94-88% by MgO, while recovery yields of pure arabinogalactan are 81-75% on purification with ion exchange resin and 91-87% on purification with MgO. 3. The optimal conditions of purification with MgO are the addition of 35mg MgO/0.5g of crude sugars, 45 minutes at $70^{\circ}C$, or 25 mg MgO, 30 minutes at $85^{\circ}C$.

• Journal of the Korean Professional Engineers Association
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• v.32 no.2
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• pp.99-109
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• 1999

The dried sea tangle added for soup prepatation to improved the taste in Korean and Japaness for long time. Attempts were made to develop the best procedures for extraction and removal of alginate by ultrafiltration and diafiltration. The summerized results of this study are as follows: 1) For hot water extraction in temperature range of 60～100$^{\circ}C$ for 4 hours, the higher temperature resulted higher yields in solids and protein. 2) Optimum sea tangle hot water extraction condition were 60～65$^{\circ}C$ for 1 hour which was cheap operating cost and high yield of good taste components. 3) The membrane flux was more higher GR 51 PP. and increase of flow rate permeate flow rate was accordingly increased. but limiting flow volume was 3.7 l/min. 4) It was found that ultration was relatively of higher recovery rate, solid and taste components, and low rejection coefficient rate than diafiltration.

• 유체기계공업학회:학술대회논문집
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• 1998.12a
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• pp.70-77
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• 1998

The rise in pressure across the impeller blade of an axial flow fan depends on the angle of attack. At a low back pressure, the air volume will be large and the angle of attack is small. The gradual increase of the back pressure approached stall zone which is not stationary but travels blade to blade passage. In consequence, a region occurs around these blades with large vibration in the flow. To avoid these stall operation, the stall detector in the axial flow fans has been designed to detect stalling condition with a manometer or differential pressure switch by electric mechanism.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.8
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• pp.1537-1546
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• 2011

The photovoltaic(PV) generation system have recently become widely used to solve the environmental problems and running out of fossil fuels. However, the study on maintenance is inadequate for PV system. This paper proposes the novel diagnosis method of output power decline to maintain the normal output performance of PV array. The diagnosis method used the proportional relation of irradiation-output current(S-I) of PV array at maximum power point(MPP). And, first order polynomial using the relation is proposed to easily apply PV system. To estimate the relation in case of separation of PV array producer and diagnosis system producer. Kalman Filter algorithm is also proposed at 30.2kW grid-connected PV system. Then, the performance of diagnosis method is evaluated using the hardware tests as well as the simulation.

• ETRI Journal
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• v.33 no.1
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• pp.6-12
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• 2011

A case study of an active transmitting patch antenna revealed a characteristic loop locus of DC power versus RF output power as drive frequency was varied, with an operational bandwidth substantially smaller than the impedance bandwidth of the radiator. An approximate simulation technique, based on separation of the output capacitance of the power transistor, yielded easily visualized plots of power dependence on internal load impedance, and a simple interpretation of the experimental results in terms of a near-resonance condition between the output capacitance and output packaging inductance.

• Journal of environmental and Sanitary engineering
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• v.18 no.3 s.49
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• pp.43-47
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• 2003

The desorption characteristics of NaY zeolite, of which Si/Al ratio is 2.36, was measured at 25${\circ}$C and 150${\circ}$C so as to be used practically as a adsorbent for separation of sulfur oxides from flue gas, for which adsorption and desorption cycles at 25${\circ}$C were repeated four times and that at 150${\circ}$C was done one time. As a result it took 30.8 at 150${\circ}$C and 164.1 minutes in average at 25${\circ}$C to reach equilibrium condition. It means that regeneration of the NaY zeolite can be done below 150${\circ}$C so that zeolite can be used for flue gas desulfurization.