• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.7
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• pp.48-55
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• 1998

We propose a new static current source model and parameter extraction method for AlGaAs/GaAs HBT. The proposed model has 9 parameters describing internal currents and are experessed with the physically meaningful parameters.The proposed parameter extraction method uses the measured dC IV curves and does not need the gummel plt data and any optimization process. the constructed model based on the proposed method predicts the measured data well.

• Korean Institute of Interior Design Journal
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• v.17 no.5
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• pp.99-106
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• 2008

Based on extraction items derived from previous related studies on viewing experiences in art museums, this study is conducted to investigate extraction factors that affect viewing satisfactions and to suggest a guideline for an effective viewing environment by clarifying a hierarchy among the extraction factors. For this study, a survey was given to museum visitors, and statistical analyses were conducted on data obtained from the survey. The results of this study are summarized as follows; 1. From an analysis of extraction items that affect overall viewing satisfaction, space and art works were found to be relatively satisfactory. 2. From correlation analyses of extraction items, a degree of concentration on art works was found to most 'affect the viewing satisfactions of art museums. 3. From factor analyses, extraction items were reduced to 11 extraction factors, and a simple extraction structure affecting the viewing satisfactions in art museums. 4. From multiple regression analyses, a extraction factors were derived, and a relative hierarchy among the factors was found.

• Proceedings of the Optical Society of Korea Conference
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• 1996.09a
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• pp.21-21
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• 1996

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1604-1608
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• 2006

A simple and efficient cloud point extraction-spectrofluorimetric method for the determination of thiamine in human urine is proposed. The procedure is based on the oxidation of thiamine with ferricyanide to form thiochrome, its extraction to Triton X-114 micelles and spectrofluorimetric determination. The variables affecting oxidation of thiamine, extraction and phase separation were studied and optimized. Under the experimental conditions used, the calibration graphs were linear over the range 2.5-1000 ng $mL^{-1}$. The limit of detection was 0.78 ng $mL^{-1}$ of thiamine and the relative standard deviation for 5 replicate determinations of thiamine at 400 ng $mL^{-1}$ concentration level was 2.42%. Average recoveries between 93-107% were obtained for spiked samples. The proposed method was applied to the determination of thiamine in human urine.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.575-576
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• 2006

It was analyzed qualitatively the light extraction in GaN-on-sapphire LEDs based on a simple model. The light extraction efficiency in the LEDs is simulated numerically by using ray tracing method. In the present study, the extraction efficiency was simulated on three different types of LEDs, which a have a different pattered sapphire substrate. And, the role of the patterned sapphire substrate are analyzed and discussed. Based on the analysis, the improvements of extraction efficiency in the LED structures were discussed and these analyses are helpful in the design of high brightness GaN LEDs.

• International Journal of Oral Biology
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• v.40 no.3
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• pp.147-150
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• 2015

The purpose of this study was to evaluate the effect of single antiplatelet treatment on delayed bleeding, in patients undergoing dental extraction. A total of 154 teeth were extracted in 94 patients with ongoing antiplatelet treatment, who were taking single antiplatelet of either aspirin or clopidogrel. All patients underwent simple dental extraction; local hemostasis was performed with gauze-biting, suturing, and/or application of a local hemostatic agent. Delayed bleeding was recorded in 5 teeth out of a total of 154 teeth after extraction, the incidence of postoperative delayed bleeding being 3.2%. The bleeding was controlled by the patients themselves, through application of pressure with additional gauze-biting. No one visited the doctor or emergency room for hemostasis. These results confirmed that patients taking single antiplatelet drugs may have teeth extracted safely without interruption of the antiplatelet treatment.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2330-2334
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• 2013

A highly selective molecularly imprinted polymer (MIP) for sarcosine, a cancer marker, was prepared and its use as solid-phase extraction (SPE) sorbent material was demonstrated. The MIP was prepared by a very simple procedure using methacrylic acid as functional monomer and a mixture acetonitrile/water (4/1, v/v) as porogen, overcoming in this way the problems usually related to the imprinting of biological polar compounds. The MIP was tested in batch experiments in order to evaluate its binding properties and then used as SPE sorbent for the selective clean-up and pre-concentration of sarcosine. The extraction protocol was successfully applied to the direct extraction of sarcosine from spiked human urine indicating that the MIP allowed sarcosine to be pre-concentrated while simultaneously interfering compounds were removed from the matrix.

• Bulletin of the Korean Chemical Society
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• v.21 no.11
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• pp.1101-1105
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• 2000

A simultaneous determination method of BTEX (benzene, toluene, ethylbenzene, o,m.p-xylene) and TPH (kerosene, diesel, jet fuel and bunker C) in soil with gas chromatography/flame ionization detection (GC-FID) was described. The effects of extracti on method, extraction solvent, solvent volume and extraction time on the extraction performance were studied. A sonication method was simpler and more efficient than Soxhlet or shaking methods. Sonication with 10 mL of acetone/methylene chloride (1 : 1, v/v) for 10 min was found to be optimal extraction conditions for 20 g of soil. Peak shapes and quantification of BTEX and TPH were excellent, with linear calibration curves over a wide range of 1-500 mg/L for BTEX and 10-5000 mg/L for TPH. Good reproducibilities by sonication were obtained, with the RSD values below 10%. By using about 20 g of soil, detection limits were 0.8 mg/L for BTEX and 10 mg/L for TPH. The advantages of this procedure are the use of simple and common equipment, reduced volumes of organic solvents, rapid extraction periods of less than 20 min, and simultaneous analysis of volatile and semivolatile compounds.

• Journal of Soil and Groundwater Environment
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• v.20 no.1
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• pp.28-35
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• 2015

In this study, the mechanisms on ultrasonication enhanced metals extraction were investigated compared with the conventional washing technique. We hypothesized the mechanisms on enhanced extraction of ultrasonication: ultrasonication increased the temperature of soil slurry and decreased average particle size of soil due to breakdown of soil aggregate. Actually, the ultrasonication increased the temperature of soil slurry to $60^{\circ}C$ in this study, and the increase in the temperature enhanced the metal extraction to 15-20% even in the conventional simple mixing. The conventional washing technique decreased average size of soil particles because of breakdown of soil aggregate, and the ultrasonication decreased the size more than that of washing. The breakdown of soil aggregate improved the contact between metals and washing agent, which enhanced the extraction of metals in the ultrasonication. Therefore, we concluded that the main mechanisms of ultrasonication are increase in the temperature and breakdown of the soil aggregate. Finally, the ultrasonicaiton increased the extractability of metals upto 40% compared to conventional washing technique.

• Plant Biotechnology Reports
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• v.4 no.1
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• pp.49-52
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• 2010

A DNA extraction method using Chelex 100 is widely used for bacteria, Chlamydomonas, and animal cell lines, but only rarely for plant materials due to the need for additional time-consuming and tedious steps. We have modified the Chelex 100 protocol and successfully developed a rapid and simple method of DNA extraction for efficient PCR-based detection of transgenes from a variety of transgenic plant and algal species. Our protocol consists of homogenizing plant tissue with a pestle, boiling the homogenized tissue in a microfuge tube with 5% Chelex 100 for 5 min, and centrifuging the boiled mixture. The supernatant, which is used for PCR analysis, was able to successfully amplify transgenes in transgenic tobacco, tomato, potato, Arabidopsis, rice, strawberry, Spirodela polyrhiza, Chlamydomonas, and Porphyra tenera. The entire DNA extraction procedure requires <15 min and is therefore comparable to that used for bacteria, Chlamydomonas, and animal cell lines.