• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.215-218
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• 2009

In this paper, temperature stable current and voltage references using simple CMOS bias circuit are proposed. To obtain temperature stable characteristics of bias circuit a bandgap reference concept is used in a conventional circuit. The parasitic bipolar transistors or MOS transistors having different threshold voltage are required in a bandgap reference. Thereby the chip area increase or the extra CMOS process is required compared to a standard CMOS process. The proposed reference circuit can be integrated on a single chip by a standard CMOS process without the extra CMOS process. From the simulation results, the reference current variation is less than ${\pm}$0.44% over a temperature range from - $20^{\circ}C$ to $80^{\circ}C$. And the voltage variation is from - 0.02% to 0.1%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.230-237
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• 2004

This paper suggests and demonstrates a novel flow measurement technique: tunable AC thermal anemometry that allows simple integration, robust measurement, and extremely high accuracy. The principle and simple theoretical analysis of the technique are presented. To find the optimal condition at which the phase lag becomes most sensitive to flow speed change, the phase lag was measured scanning the heating frequency from 1 to 100 Hz, while the flow speed of ethanol was increased stepwise from 0 to 40 mm/s. The sensitivity of phase lag depended on the heating frequency and the flow speed. It was possible to measure the flow speed of 0.7 mm/s with the resolution of 0.1 mm/s at 4 Hz.

• Bulletin of the Korean Chemical Society
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• v.27 no.8
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• pp.1199-1202
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• 2006

A simple, sensitive and rapid spectrofluorimetric method was developed for determination of mefenamic acid in pharmaceutical preparation and human urine. The procedure is based on the oxidation of mefenamic acid with cerium (IV) to produce cerium (III), and its fluorescence was monitored at 354 nm after excitation at 255 nm. The variables affecting oxidation of drug were studied and optimized. Under the experimental conditions used, the calibration graphs were linear over the range 0.03-1.5 mg $L^{-1}$. The limit of detection was 0.009 mg $L^{-1}$ and the relative standard deviation for 5 replicate determinations of mefenamic acid at 1.0 mg $L^{-1}$ concentration level was 1.72%. Good recoveries in the range of 102-107 and 102-109% were obtained for pharmaceutical preparation and human urine, respectively. The proposed method was applied to the determination of MF in one pharmaceutical preparation and human urine. The amounts of mefenamic acid found are very similar to those obtained by a standard method.

• YAKHAK HOEJI
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• v.45 no.1
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• pp.34-38
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• 2001

The Phellodendri Cortex of Phellodendron amurense (Rutaceae) is known to contain a number of isoquinoline alkaloid, and berberine, palmatine, jateorrhizine, phellodendrine and magnoflorine are the major constituents of protoberberine alkaloids. For the determination of protoberberine alkaloids from Phellodendri Cortex and berberine chloride from the preparation, the new spectrophotometric method was developed with a simple and selective sample clean-up using thiocyanatocobaltate[II] complex ion. Samples were extracted with 0.1 mM hydrochloric acid, potassium biphthalate reagent, thiocyanatocobaltate reagent and 1.2-dichloroethane for 60 min. The absorbance of protoberberine alkaloid complexes in 1.2-dichloroethane solution was measured at 625 nm. Calibration curve for berberine was linear over the concentration range of 0.05~0.30 mg/ml 1.2-dichloroethane. The method proved to be rapid, simple and reliable for the determination of protoberberine alkaloids from Phellodendri Cortex and berberine chloride from the preparation.

• Preventive Nutrition and Food Science
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• v.1 no.1
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• pp.106-110
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• 1996

Bromelain(EC 3.4.22.4), the collective name for the proteolytic enzymes found in tissues of the plant family Bromeliaceae(pineapple), has been used as a tenderizing agent in food processing, and as an antiinflammatory agent in pharmaceuticals. In this paper, we describe the simple purification method of bromelain using Korean pineapple fruit. After removing contaminants at 30% saturation of ammonium sulfate, the supernatant obtained was treated again with ammonium sulfate to 80% saturation. Wit the above salt fractionation, partially purified bromelain could be obtained. To get highly purified bromelain, the previous 30% to 80% ammonium sulfate treated precipitate was dialyzed against 25mM sodium acetate buffer(pH 5.0) followed by passing through a CM- cellulose cation exchange column. Fruit bromelain was eluted as a major peak at 0.5~0.8M NaCI gradient. The present method is simpler with high wield than the traditional purification method-acetone treatment and several consecutive chromatographic processes.

• Journal of the Korean Mathematical Society
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• v.58 no.6
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• pp.1407-1419
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• 2021

The Iwasawa decomposition NAK of the Lie group G = SO₀(2, 1) with a left invariant metric produces Riemannian submersions G → N\G, G → A\G, G → K\G, and G → NA\G. For each of these, we calculate the curvature of the base space and the lifting of a simple closed curve to the total space G. Especially in the first case, the base space has a constant curvature 0; the holonomy displacement along a (null-homotopic) simple closed curve in the base space is determined only by the Euclidean area of the region surrounded by the curve.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.416-420
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• 2003

In this paper, we implemented a dual-resolution image database system for the fast naked-eye retrieval using interpolation. This system can solve two conventional problems : a blocking noise at zoom-out image in single high resolution method and a big storage to store in simple dual-resolution image database system. The proposed method makes a subsampled image by subsampling a original image, and then a interpolated image of it using interpolation. After that, a hybrid dual-resolution image database is composed based on the differential image between the interpolated image and the original image. Experimental results of simulating through 60 sample images shows that the proposed method is 0.011 second faster than simple high-resolution method in the retrieval time - one is 0.003 second, the other is 0.014 second, respectively. Also, that improves 14.7% more than simple dual-resolution method in the stored size - one is 19,821 byte, the other is 16,910 byte, respectively.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.2
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• pp.88-95
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• 2009

There are many assessment techniques used for occupational risk factors of MSDs in the workplaces. However, because all ergonomic assesment techniques or tools are based on theoretical background derived from workphysiology, biomechanics, psychophysics, industrial hygiene, work system, and etc, it is impossible to compare the assessment techniques. This study was conducted to compare the excess rates of risk factors among ergonomic assessment techniques and to make alternative methods. Site-visits to 6 automobile products and parts company provided data for process repeated work where the produced data was examined for evaluating the relationship between workplace lay-out and work posture by using ergonomic assessment techniques. We evaluated 157 jobs for simple repeated work and 37 jobs for manual materials handling (MMH). In simple repeated work, the exceeded rates of AC were 36.3% in OWAS method and 93.0% in RULA method. The exceeded rate for RULA method was significantly higher than those for OWAS method (p<0.05). In MMH, the exceeded rates of AC were 80.0% in NLE method and 76.5% in WAC method. Statistically significant differences were not identified in the exceeded rates for NLE and MAC methods (p<0.05). The analyzed results among ergonomic assessment techniques (OWAS, RULA, NLE/WAC) were applied to the same work places performing simple repeated work and manual materials handling simultaneously. The applied results showed statistically significant differences (p<0.05) among ergonomic assessment techniques (OWAS, RULA, NLE/WAC). Exceeded rates of four ergonomic assessment techniques in decreasing order was "RULA>NLE>WAC>OWAS". The RULA method was the strongest assessment technique for automobile products and parts company. We discovered that the results could easily be overestimated or underestimated when the ergonomic assessment techniques were not applied correctly during the evaluation process. Therefore, we recommend using at least 2 methods when evaluating and analysing the results.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.158-164
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• 2019

Molecular characterization of different genotypes reveals accurate information about the degree of genetic diversity that helps to develop a proper breeding program. In this study, a total of 30 EST-based simple sequence repeat (EST-SSR) markers derived from trumpet lily (Lilium longiflorum) were used across 11 native lily species for their genetic relationship. Among these 30 markers, 24 SSR markers that showed polymorphism were used for evaluation of diversity spectrum. The allelic number at per locus ranged from 1 at SSR2 locus to 34 alleles at SSR15 locus, with an average of 11.25 alleles across 24 loci observed. The polymorphic information content, PIC, values ranged from 0.0523 for SSR9 to 0.9919 for SSR2 in all 24 loci with an average of 0.3827. The allelic frequency at every locus ranged from 0.81% at SSR2 locus to 99.6% at SSR14 locus. The pairwise genetic dissimilarity coefficient revealed the highest genetic distance with a value of 81.7% was in between L. dauricum and L. amabile. A relatively closer genetic distance was found between L. lancifolium and L. dauricum, L. maximowiczii and L. concolor, L. maximowiczii and L. distichum (Jeju), L. tsingtauense and L. callosum, L. cernuum and L. distichum (Jeju ecotype), of which dissimilarity coefficient was 50.0%. The molecular fingerprinting based on microsatellite marker could serve boldly to recognize genetically distant accessions and to sort morphologically close as well as duplicate accessions.

• Nutrition Research and Practice
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• v.16 no.6
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• pp.745-754
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• 2022

BACKGROUND/OBJECTIVES: The incidence of cardiovascular diseases (CVDs) has increased worldwide. Although a low serum vitamin D level is known to be associated with the risk of CVD, the mechanism is not well understood yet. The aim of this study was to determine the relationship of serum 25-hydroxyvitamin D₃ (25[OH]D) with homocysteine and apolipoprotein B (ApoB). SUBJECTS/METHODS: Of 777 subjects recruited from one health promotion center for routine heath exam from January 2010 to December 2016, 518 subjects were included in this study. Serum 25(OH)D, serum homocysteine, and other metabolic parameters including ApoB were analyzed. Simple and partial correlations were carried out after adjustments. Simple linear regression analysis was used for precise correlation of parameters. Multivariate regression analysis was done to know which factor (serum homocysteine or ApoB) was more related to serum 25(OH)D after adjustments. Finally, logarithms of homocysteine concentrations according to tertiles of serum 25(OH)D were compared. RESULTS: After sex and age adjustments, serum 25(OH)D showed negative correlations with serum homocysteine (r' = -0.114) and ApoB (r' = -0.098). In simple linear regression analysis, serum 25(OH)D showed a significant negative correlation with ApoB (P = 0.035). However, in multivariate regression analysis, serum 25(OH)D was significantly associated with serum homocysteine after adjustments (P = 0.022). In addition, serum homocysteine concentration was significantly high in the lowest 25(OH)D group (P = 0.046). CONCLUSION: Serum 25(OH)D concentration showed a stronger negative association with serum homocysteine than with ApoB.