• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.3 s.234
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• pp.376-383
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• 2005

In the paper we investigate characteristics of a transitional behavior from a premixed flame to a triple flame in a lifted flame according to the change of equivalence ratio. In previous study, we showed that the stabilized laminar lifted flame regime is categorized by regimes of premixed flame, triple flame and critical flame. A gas-chromatograph is used to measure concentration field, a smoke-wire system is used to measure streak line, and a PIV system is used to measure velocity field in lifted flame. In the visualization experiment of smoke wire, the flow divergence and redirection reappeared in premixed flame as well as triple flame. Thus we cannot express the flame front of lifted flame has a behavior of triple flame with only flow divergence and redirection. In PIV measurement, flow velocity for those three flames has minimum value at the tip of flame front. To differentiate triple flame and premixed flame, $\Phi$ value of partially premixed fraction is employed. The partially premixed fraction $\Phi$ was constant in premixed flame. In critical flame small gradient appears over the whole regime. In triple flame, typical diffusion flame shape is obtained as parabolic distribution type due to diffusion flame trailing.

• The Mathematical Education
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• v.60 no.1
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• pp.1-19
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• 2021

This study investigates students' conceptions of fractions from a measurement approach while providing a technological environment designed to support students' understanding of the relationships between quantities and adjustable units. 13 third-graders participated in this study and they were involved in a series of measurement tasks through task-based interviews. The tasks were devised to investigate the relationship between units and quantity through manipulations. Screencasting videos were collected including verbal explanations and manipulations. Drawing upon the theory of semiotic mediation, students' constructed concepts during interviews were coded as mathematical words and visual mediators to identify conceptual profiles using a fine-grained analysis. Two students changed their strategies to solve the tasks were selected as a representative case of the two profiles: from guessing to recursive partitioning; from using random units to making a relation to the given unit. Dragging mathematical objects plays a critical role to mediate and formulate fraction understandings such as unitizing and partitioning. In addition, static and dynamic representations influence the development of unit concepts in measurement situations. The findings will contribute to the field's understanding of how students come to understand the concept of fraction as measure and the role of technology, which result in a theory-driven, empirically-tested set of tasks that can be used to introduce fractions as an alternative way.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.4
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• pp.521-539
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• 2016

The structures of partitive and quotitive division of fractions are dealt with differently, and this led to using partitive division context for helping develop invert-multiply algorithm and quotitive division for common denominator algorithm. This approach is unlikely to provide children with an opportunity to develop an understanding of common structure involved in solving different types of division. In this study, I propose two approaches, measurement approach and isomorphism approach, to develop a unifying understanding of fraction division. From each of two approaches of solving quotitive division based on proportional reasoning, I discuss an idea of constructing a measure space, unit of which is a quantity of divisor, and another idea of constructing an isomorphic relationship between the measure spaces of dividend and divisor. These ideas support invert-multiply algorithm for quotitive as well as partitive division and bring proportional reasoning into the context of fraction division. I also discuss some curriculum issues regarding fraction division and proportion in order to promote the proposed unifying understanding of partitive and quotitive division of fractions.

• The Korean Journal of Food And Nutrition
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• v.30 no.6
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• pp.1286-1291
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• 2017

In this study, Pyracantha angustifolia (Franch.) C. K. Schneid was extracted with 70% methanol at room temperature for 48 hrs and concentrated under reduced pressure to measure its total polyphenol contents; furthermore, the effect of electron donating ability was examined. Methylene chloride, ethyl acetate, and methanol were used to fractionate the extract to testify total polyphenol contents, electron donating abilities, the removal abilities of superoxide radical as well as hydrogen peroxide. The total polyphenol contents were $2007.30{\pm}109.28{\mu}g\;GAE/mL$ in 70% methanol extract, $273.39{\pm}10.19{\mu}g\;GAE/mL$ in methylene chloride fraction, $80.57{\pm}0.64{\mu}g\;GAE/mL$ in ethyl acetate fraction, and $1,160.87{\pm}44.71{\mu}g\;GAE/mL$ in methanol fraction. The total polyphenol contents showed significant differences (p<0.05) between the solvents. The electron donating ability was $79.07{\pm}7.31%$ for 70% methanol extract, $22.34{\pm}0.64%$ for methylene chloride fraction, $5.33{\pm}0.28%$ for ethyl acetate fraction, and $32.26{\pm}1.10%$ for methanol fraction. The electron donating abilities were significantly different(p<0.05) between the solvents. The removal ability of superoxide radical was $0.018{\pm}0.003$ for 70% methanol extract, $0.007{\pm}0.002$ for methylene chloride fraction, $0.0147{\pm}0.003$ for ethyl acetate fraction, and nothing for methanol fraction. The measurement of hydrogen peroxide decomposition was $0.022{\pm}0.0046$ for 70% methanol extract, $0.0027{\pm}0.0015$ for methylene chloride fraction, $0.0037{\pm}0.0012$ for ethyl acetate fraction, and $0.0009{\pm}0.0001$ for methanol fraction.

• KSBB Journal
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• v.28 no.2
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• pp.131-136
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• 2013

The hydrolysates prepared with various enzyme digestion of Capsosiphon fulvescens were used to measure the inhibitory effects against angiotensin I converting enzyme (ACE). The commercially available enzymes such as Celluclast, Viscozyme, Lysing enzyme, Flavourzyme, Alcalase and Pectinex were used to digest C. fulvescens and produce hydrolysates. The maximum ACE inhibitory activity was observed using Alcalase hydrolysis (72.9%). The optimal conditions of Alcalase extraction were pH 8.0 and extraction time for 12 hr. The hydrolysates were fractionated using preparative-LC and anion-exchange chromatography on DEAE-cellulose and the fraction B and B-2 were isolated. The ACE inhibitory activity of fraction B-2 by anion-exchange chromatography was 82.6%. The molecular weight of fraction B-2 estimated using size exclusion chromatography was about 1 kDa. The monosaccharide composition of the fraction B-2 was determined to be mannose (1.1%), glucuronic acid (1.3%), galactose (1.3%) and glucose (96.3%).

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.16 no.5
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• pp.516-524
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• 1987

This paper presents experimental data of fluctuation characteristics of local void fraction of air-water two-phase flow which are associated with the flow pattern, annular gap size and radial location in vertical concentric annuli with coefficient of skewness and kurtosis. The annular gap widths are 13mm, 11mm, and 9mm for a 38m inner diameter as the lucite outer tube. A electrical conductivity probe was used to measure the local void fraction and traversed diametrically from inner wall to outer wall using radial increments of 2mm. It was shown that distribution of the coefficient of skewness and kurtosis, which is related that the one is the asymmetry and the other peakness of local void fraction distribution was influenced by flow pattern, annular gap size and radial location.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.20 no.42
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• pp.73-85
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• 1997

In the product liability age the demand on quality is extremely high and inspection and test are automated. The process capability indices $C_p, {\;}C_{pk}$ and p control chart widely used to provide unitless measure of process performance and process control. Traditional process capability indices $C_p, {\;}C_{pk}$ do not represent the process variation from target value. The convention p chart for control of fraction nonconforming becomes inadequate when the fraction nonconforming becomes very small such as PPM level production system. This paper proposes process performance measure considering quadratic loss function and cumulative counts control chart for control of PPM level production system.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.155-160
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• 2003

The purpose of this study was to purify epidermal growth factor(EGF) as growth factor from human colostrum. The effects of purified EGF fraction were directly related to the growth of cells. Results were as follows; After eliminated fat from colostrum, skim milk was obtained. We obtained the EGF fraction by performing ultrafiltration and gel filtration, and then were convicted by SDS-PAGE. The result of analysis of purified EGF fraction by high performance liquid chromatography(HPLC) was shown a peak at 31.185 min period. And it was similar with standard EGF that was shown a peak at 31.545 min. 10 ng of EGF was contained in 10 mg/mL through immunoassay to measure EGF content from isolated fraction. After SDS-PAGE, isolation degree of purified fraction was convicted through western blotting. BALB/3T3 cell was the most effectively stimulated and proliferated at 1 mg/mL concentration of the purified EGF fraction and percentage of cell proliferation was about 95%. In the case of IEC-6 cell, that was about 71%.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.148-151
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• 2009

We consider the problem of optimizing the performance of a system with resources shared by non-cooperative users. The worst-cast ratio between the cost of a Nash equilibrium and the optimal cost, called Price of Anarchy, is investigated. It measures the performance degradation due to the users' selfish behavior. As the objective function of the optimization problem, we are concerned in a load balancing measure, which is different from that used in the previous works. Also we consider the Stackelberg scheduling which can assign a fraction of the users to resources while the remaining users are free to act in a selfish manner.

• Communications of Mathematical Education
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• v.19 no.4 s.24
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• pp.715-731
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• 2005

There are five contexts of division algorithm of fractions such as measurement division, determination of a unit rate, reduction of the quantities in the same measure, division as the inverse of multiplication and analogy with multiplication algorithm of fractions. The division algorithm, however, should be taught by 'dividing by using reciprocals' via 'measurement division' because dividing a fraction by a fraction results in 'multiplying the dividend by the reciprocal of the divisor'. If a fraction is divided by a large fraction, then we can teach the division algorithm of fractions by analogy with 'dividing by using reciprocals'. To achieve the teaching-learning methods above in elementary school, it is essential for children to use the maniplatives. As Piaget has suggested, Cuisenaire color rods is the most efficient maniplative for teaching fractions. The instruction, therefore, of division algorithm of fractions should be focused on 'dividing by using reciprocals' via 'measurement division' using Cuisenaire color rods through analogy if necessary.