• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.135-144
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• 2018

The purpose of this study is to investigate the relationship between oral health behavior and dietary habits and caries occurrence test and to provide basic data necessary for prevention of dental caries. The average salivary salivary fraction was 8.35ml and the non - amorphous salivary fraction was 2.41ml. The salivary buffering ability was 9.29 and the mean glucose retention time was 15.81 minutes. In the Streptococcus mutans colony count test, low risk group <105 was 80.5% and low risk group <105 was 84.4% in Lactobacillus colony count test. Correlation between caries test scores showed a positive correlation between salivary ratio and non - salivary ratio, saliva buffering ability, non - salivary fraction and glucose retention time, and Lactobacillus. Factors affecting the irritant saliva fraction were alcohol as a factor affecting the ratio of nuts, pork, and non - irritant saliva. In order to prevent dental caries, proper dietary control education should be combined with dental caries activity test and oral health education for proper eating habits.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.317-317
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• 2011

Enhanced ICRF (Ion Cyclotron Range of Frequency) ion heating of H-mode D(H) plasma will be tried in 2011 KSTAR experimental campaign. Minority heating is a main ion heating scheme in the ICRF. Its efficiency increases as the hydrogen minority ratio increases in deuterium plasmas. And it should be sustained at a lower level than the critical minority ratio. Consequently, it is important to elevate the critical ratio to maximize ion heating and it is possible by increasing the ion temperature or parallel wave number (k${\parallel}$) of the antenna. Increasing the k${\parallel}$ is not a good approach since the coupling efficiency decreases exponentially with regard to k${\parallel}$ as well. So the remaining method is to increase ion temperature by using NB (Neutral Beam). Ion heating fraction of NB increases as the electron temperature increases. Therefore, we will try to heat electron by using ECH together with NB ion heating before ICRF power injection. The ICRF heating efficiency will be compared with respect to several NB+ECH+ICRF heating combinations through several diagnostics such as XICS (Xray Imaging Crystal Spectroscopy), CES (Charge Exchange Spectroscopy) and neutron measurement. The theoretical background and the experimental results will be presented in more detail in the conference.

• Journal of the Korean Ceramic Society
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• v.45 no.8
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• pp.439-442
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• 2008

A series of reaction-sintered SiC was fabricated from preforms with varying volume fractions of two resin-coated SiC particles of different sizes (63 and $18{\mu}m$). The electrical resistivity and mechanical strength were eventually optimized at the small particle volume fraction of $0.3{\sim}0.4$, at which point the porosity of the preform was minimized. This study experimentally proves that additional processes after the formation of the preform, such as silicon infiltration and reaction sintering, do not apparently alter the optimum volume fraction of the preform packing, predicted by an existing analytical model based on solid packing. Thus, the volume fraction of particles of different sizes can be determined practically through the solid packing model to fabricate RSSCs with optimal properties.

• The KIPS Transactions:PartD
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• v.8D no.2
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• pp.175-180
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• 2001

This paper presents the optimal fraction of validation set to obtain a prediction accuracy of software failure count or failure time in the future by a neuro-fuzzy system. Given a fixed amount of training data, the most popular effective approach to avoiding underfitting and overfitting is early stopping, and hence getting optimal generalization. But there is unresolved practical issues : How many data do you assign to the training and validation set\ulcorner Rules of thumb abound, the solution is acquired by trial-and-error and we spend long time in this method. For the sake of optimal fraction of validation set, the variant specific fraction for the validation set be provided. It shows that minimal fraction of the validation data set is sufficient to achieve good next-step prediction. This result can be considered as a practical guideline in a prediction of software reliability by neuro-fuzzy system.

• Membrane Journal
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• v.24 no.3
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• pp.223-230
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• 2014

A numerical analysis was performed for concentration of methane from the biogas using a polysulfone hollow fiber membrane permeator. Governing equations were derived for the countercurrent flow and numerically solved by using the Compaq Visual Fortran 6.6 software. When the methane mole fraction of feed was 0.5, the mole fraction of retentate increased from 0.5 to 0.8; the normalized retentate flow rate to the feed flow rate decreased from 1.0 to 0.57 at the given typical operating condition as the feed gas flowed from the inlet to the outlet of the membrane. As the methane mole fraction of feed was changed to 0.9, the methane mole fraction of retentate became 0.93 and the normalized retentate flow rate was changed to 0.91. When the pressure ratio of the permeate to the feed was varied from 0.33 to 0.17, there was a little difference in the methane mole fraction of retentate for the low stage cut of 0.1, whereas there was an significant increment for the high stage cut of 0.3. The retentate methane mole fraction remained relatively high despite the change of a stage cut as the area of the membrane increased from $1.14m^2$ to $2.57m^2$.

• Applied Chemistry for Engineering
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• v.30 no.2
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• pp.155-159
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• 2019

As a part of improving the quality for the fraction of the waste plastics pyrolysis oil (WPPO), the recovery of paraffin components contained in the fraction was investigated by dimethylformamide (DMF) equilibrium extraction. The fraction of a distilling temperature of $120{\sim}350^{\circ}C$ recovered from WPPO by the simple distillation and the aqueous solution of DMF were used as a raw material and solvent, respectively. The concentrations of paraffin components ($C_{12}$, $C_{14}$, $C_{16}$ and $C_{18}$) contained in the raffinate decreased by increasing the mass fraction of water in the solvent at an initial state ($y_{w,0}$), whereas, the concentrations of paraffin components contained in the raffinate increased by increasing the mass ratio of the solvent to the feed at an initial state $(S/F)_0$. The concentrations of $C_{12}$, $C_{14}$, $C_{16}$ and $C_{18}$ paraffin components present in the raffinate recovered at $(S/F)_0=10$ were about 1.37, 2.0, 2.46 and 3.16 times higher than those of the raw materials, respectively. Recovery rates (residue rates present in raffinate) of paraffin components rapidly increased with increasing $y_{w,0}$, and decreasing $(S/F)_0$. The raffinate recovered through this study was expected to be used as a renewable energy.

• Steel and Composite Structures
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• v.25 no.6
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• pp.717-726
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• 2017

In this paper, a new simple shear deformation theory for bending analysis of functionally graded plates is developed. The present theory involves only three unknown and three governing equation as in the classical plate theory, but it is capable of accurately capturing shear deformation effects, instead of five as in the well-known first shear deformation theory and higher-order shear deformation theory. A shear correction factor is, therefore, not required. The material properties of the functionally graded plates are assumed to vary continuously through the thickness, according to a simple power law distribution of the volume fraction of the constituents. Equations of motion are obtained by utilizing the principle of virtual displacements and solved via Navier's procedure. The elastic foundation is modeled as two parameter elastic foundation. The results are verified with the known results in the literature. The influences played by transversal shear deformation, plate aspect ratio, side-to-thickness ratio, elastic foundation, and volume fraction distributions are studied. Verification studies show that the proposed theory is not only accurate and simple in solving the bending behaviour of functionally graded plates, but also comparable with the other higher-order shear deformation theories which contain more number of unknowns.

• Communications of Mathematical Education
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• v.23 no.1
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• pp.145-174
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• 2009

Based on the thinking that people can understand more clearly when the problem is related with their prior knowledge, the Purpose of this study was to analysis students' informal knowledge, which is constructed through their mathematical experience in the context of real-world situations. According to this purpose, the following research questions were. 1) What is the characteristics of students' informal knowledge about fraction before formal fraction instruction in school? 2) What is the difference of informal knowledge of fraction according to reasoning ability and grade. To investigate these questions, 18 children of first, second and third grade(6 children per each grade) in C elementary school were selected. Among the various concept of fraction, part-whole fraction, quotient fraction, ratio fraction and measure fraction were selected for the interview. I recorded the interview on digital camera, drew up a protocol about interview contents, and analyzed and discussed them after numbering and comment. The conclusions are as follows: First, students already constructed informal knowledge before they learned formal knowledge about fraction. Among students' informal knowledge they knew correct concepts based on formal knowledge, but they also have ideas that would lead to misconceptions. Second, the informal knowledge constructed by children were different according to grade. This is because the informal knowledge is influenced by various experience on learning and everyday life. And the students having higher reasoning ability represented higher levels of knowledge. Third, because children are using informal knowledge from everyday life to learn formal knowledge, we should use these informal knowledge to instruct more efficiently.

• The Korean Journal of Pharmacology
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• v.8 no.1
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• pp.31-40
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• 1972

The author studied the actions of ouabain and diphenylhydantoin sodium on the ATPase activity in mitochondrial fraction isolated from rabbit heart and compared with that of quinidine. The results obtained are as follows: 1) In studying the $(Na^++K^+)-activated$ ATPase activity, the rabbit heart isolated was immediately frozen for 7-9 days (ageing of preparation) and thereafter the mitochondria1 fraction obtained by differential centrifugation technic was treated with solution A containing 0.15% deoxycholate for 24-48 hours at $-10^{\circ}C$ before using in experiment. These methods increased the activity ratio to 0.87-0.98. 2) The $(Na^++K^+)-activated$ ATPase activity in mitochondrial fraction of rabbit heart was not completely but markedly inhibited by ouabain. This inhibitory action of ouabain was moderately antagonised by $K^+$ concentration at constant Na concentration. 3) Diphenylhydantoin sodium in concentration of $5{\times}10^{-4}{\sim}10^{-3}M$ stimulated markedly not only $Mg^{++}-dependent$ ATPase activity but also $(Na^++K^+)$-activated ATPase activity and in concentration lower than $10^{-6}M$ had little effect. However, this effect of diphenylhydantoin was markedly increased in the presence of $Na^+$ alone rather than $K^+$ alone, but lesser than that effect in the presence of both $Na^+$ and $K^+$, together. The stimulating effect of diphenylhydantoin was specifically antagonized by ouabaion. 4) When the rabbits were intravenously injected with ouabain and diphenylhydantion respectively, $(Na^++K^+)-activated$ ATPase activity of rabbit heart of ouabain-treated group was much decreased and both $(Na^++K^+)-activated$ ATPase and $Mg^{++}-activated$ ATPase activity were moderately increased in diphenylhydantoin-treated rabbit group. 5) The $(Na^++K^+)-activated$ ATPase activity in mitochondrial fraction of rabbit heart was slightly inhibited by quinidine in high concentration of $10^{-4}M$, but nearly little effect was observed below the concentration of $5{\times}10^{-5}M$. 6) It might be possible to conclude that diphenylhydantoin specifically antagonised the action of ouabain on the membrane ATPase, which is different from the action of quinidine.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.155-158
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• 2002

Fabrication process of metal/intermetallic laminated composites by using self-propagating high temperature synthesis(SHS) reactions between Ni and Al elemental metal foils have been investigated. Al foils were sandwiched between Ni foils and heated in a vacuum hot press to the melting point of aluminium. SHS reaction kinetics was thermodynamically analyzed through the final volume fraction of the unreacted Al related with the initial thickness ratio of Ni:Al and diffusion bonding stage before SHS reaction. Thermal aging of laminated composites resulted in the formation of functionally gradient series of intermetallic phases. Microstructure showed that the main phases of intermetallics were NiAl and $Ni_3Al$ having higher strength at room and high temperatures. The volume fractions of intermetallic phases were measured as 82.4, 58.6, 38.4% in 1:1, 2:1, 4:1 initial thickness ratio of Ni:Al.