• Korean Journal of Food Science and Technology
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• v.21 no.3
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• pp.360-363
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• 1989

The initial moisture adsorption of soybeans was examined under the conditions : RH, 57-86% ; temperature, $16^{\circ}-34^{\circ}C$, and storage time, 100 hours. The changes in moisture content as a function of time held a relation: log dw/dt=b log t + log a, where w is the moisture content (%, db), t is time (hour) and a and b are the parameters which were calculated from the experimental data. The calculated moisture content from the equation agreed well with the measured moisture content. The activation energy of initial adsorption rate was about 15500cal/g-mole in all soybeans. The initial adsorption rate at temperature $16^{\circ}-28^{\circ}C$ could be estimated from a following equation : log(log dw/dt)=-15500/2.303RT.

• Journal of the Korean Magnetics Society
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• v.23 no.6
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• pp.193-199
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• 2013

The regional distribution of magnetic isotropy depending on the post annealing condition for the dual-type structure GMR-SV (giant magnetoresistance-spin valve) of NiFe/Cu/NiFe/IrMn/NiFe/Cu/NiFe multilayer was investigated. The rotation of in-plane ferromagnetic layer induced by controlment of the post annealing temperature inside of the vacuum chamber. The magnetoresistive curves of a dual-type IrMn based GMR-SV depending on the direction of the magnetization easy axis of the free layer and the pinned layer are measured by between $0^{\circ}$ and $360^{\circ}$ angles for the applied fields. The optimum annealing temperature having a steady and isotropy magnetic sensitivity of 1.52 %/Oe was $107^{\circ}C$ in the rotational section of $0{\sim}90^{\circ}$. By investigating the switching process of magnetization for an arbitrary measuring direction, the in-plane orthogonal magnetization for the dual-type GMR-SV multilayer can be used by a high sensitive biosensor for detection of magnetized micro-beads.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.72-80
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• 2010

Possibility of the usage of sludge generated in coal mine drainage treatments as a briquette additive was investigated by the combination of industrial, elemental, and combustion experiments. A series of briquettes having 2% and 6% of sludge were used for the experiments. Compared to the control sample, our results show that all experimental values for the briquettes are very similar. In particular, it is worthy to note that there is no obvious difference in calorific values for the briquettes containing 2% or 6% of sludge. The calorific values are 4,250~4,360 kcal/kg, 4,240~4,250 kcal/kg, 4,180~4,210 kcal/kg, and 4,270~4,360 kcal/kg for the control sample, briquette containing 6% of Hambaek sludge, briquette containing 6% of Hamtae sludge, and briquette containing 2% of Hambaek sludge, respectively. Results of ash fusion temperature show that the temperature is greater than $1,550^{\circ}C$ for the control sample. However, the temperature for the briquettes with 6% of Hambaek sludge and 2% of Hambaek or Hamtae sludge is $1,510^{\circ}C$. For a briquette containing 6% of Hamtae sludge, the temperature of ash fusion is $1,530^{\circ}C$. After combustion, environmental impacts of the briquettes with sludge were tested. Little environmental influence was observed for the combusted briquettes with sludge.

• Journal of Educational Research in Mathematics
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• v.19 no.4
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• pp.479-491
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• 2009

This paper researches the possibility of introducing Descartes' theorem to mathematically gifted students. Not only is Descartes' theorem logically equivalent to Euler's theorem but is hierarchically connected with Gauss-Bonnet theorem which is the core concept on differential geometry. It is possible to teach mathematically gifted students Descartes' theorem by generalizing mathematical property in solid geometry through analogical reasoning, that is, so in a polyhedrons the sum of the deficient angles is $720^\circ$ as in an polygon the sum of the exterior angles is $360^\circ$. This study introduces an alternative method of instruction that we enable mathematically gifted students to reinvent Descartes' theorem through analogical reasoning instead of deductive reasoning.

• Economic and Environmental Geology
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• v.20 no.2
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• pp.107-118
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• 1987

The south ore deposits of the Dunjeon gold mine is a fissure-filling vein emplaced in the granitoids, skarnized and hornfelsified rocks of Ordovician Dumudong formation. The vein mineral paragenesis is complicated by repeated fracturing but three distinct depositional stages can be recognized; (1) base metal sulfides stage, (2) base metal sulfides, antimony-bismuthsulfosalts and native metals stage, (3) barren carbonates stage. Gold was mainly deposited in stage II. Fluid inclusion data indicate that fluid temperatures were from $310^{\circ}C$ to $402^{\circ}C$ during stage I and then declined steadily to $148^{\circ}C$ in the closing late stage III. Salinities were in the range of 0.4 to 5.0 equivalent weight percent NaCl and do not reveals any systematic trend through stag I, II and III. Ore mineralogy suggests that temperatures and sulfur fugacities in the earlier stage II were in the range of $340^{\circ}C$ to $360^{\circ}C$, $10^{-8}$ to $10^{-9}$ atm. respectively and then declined steadily to the range of $185^{\circ}C$ to $200^{\circ}C$ and $10^{-17}$ to $10^{-19}$atm. in the later stage II.

• Transactions on Electrical and Electronic Materials
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• v.9 no.5
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• pp.186-192
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• 2008

Cross linked polyethylene (XLPE) insulators are used as insulation in ultra-high voltage electric power cables. This study investigated the electrical properties of XLPE at different temperatures. The electrical properties of the changing tree phenomenon was examined as a function of temperature applied to the electrical conductors by measuring the partial discharge at $25^{\circ}C$ to $80^{\circ}C$ and applied voltages to the electrodes ranging from 1 kV to 40 kV. The activity of the partial discharge was examined at various temperatures using the K-means distribution. The results revealed the specimen at $80^{\circ}C$ to have the lowest inception voltage and breakdown voltage. In addition, the core of clusters was moved $0^{\circ}$ and $180^{\circ}$ at the positive region and $180^{\circ}$ and $360^{\circ}$ in the negative region in the K-means. The distribution of clusters was concentrated on the inception condition and spread out widely at the breakdown voltage.

• Journal of Energy Engineering
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• v.17 no.1
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• pp.8-14
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• 2008

The effects of calcium type catalysts addition on the thermal decomposition of low density polyethylene (LDPE) and ethylene vinyl acetate (EVA) resin have been studied in a thermal analyze. (TGA, DSC) and a small batch reactor. The calcium type catalysts tested were calcinated dolomite, lime, and calcinated oyster shell. As the results of TGA experiments, pyrolysis starting temperature for LDPE varied in the range of $330{\sim}360^{\circ}C$ according to heating rate, but EVA resin had the 1st pyrolysis temperature range of $300{\sim}400^{\circ}C$ and the 2nd pyrolysis temperature range of $425{\sim}525^{\circ}C$. The calcinated dolomite enhanced the pyrolysis rate in LDPE pyrolysis reaction, while the calcium type catalysts reduced the pyrolysis rate in EVA pyrolysis reaction. In the DSC experiments, addition of calcium type catalysts reduced the melting point, but did not affect to the heat of fusin. Calcinated dolomite reduced 20% of the heat of pyrolysis reaction. In the batch system experiments, the mixing of calcinated dolomite and lime enhanced the yield of fuel oil, but did not affect to the distribution of carbon numbers.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.568-573
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• 2008

Kinetic tests on pyrolysis of waste fishing net [WFN; nylon-6], waste ship lubricating oil [WSLO] and their mixture were carried out by thermogravimetric analysis (TGA) with heating rate of 0.5, 1.0, and $2.0^{\circ}C/min$. Pyrolysis of waste fishing net started at $300^{\circ}C$, and the main region of decomposition temperature was between 360 and $440^{\circ}C$ at each heating rate. Decomposition temperature of the mixture of WFN and WSLO was lower than that of WFN and WSLO, and the shape of thermogravimetic graph of mixture was different as well. The corresponding kinetic parameters including activation energy and pre-exponential factor were determined by differential method over the degree of conversions. The values of activation energies for the mixture of WFN and WSLO were between 98 and 427 kJ/mol as the conversion increased from 5% to 95%. Tubing reactor was used to analysis of pyrolyzed oil at $440^{\circ}C$ for 80 min. The selectivity of specific hydrocarbons was not detected and the carbon number distribution of the pyrolyzed oil was below $C_{22}$.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.1
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• pp.39-46
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• 2015

In this paper, a gas sensor using a modified $90^{\circ}$ hybrid coupler structure with conducting polymer which operates at 2.4 GHz is represented. Conducting polymers are used to the gas sensing material in proposed sensors. The conducting polymer varies its electrical property, such as work function and conductivity corresponding to the certain gas. To verify this variation of electrical property of conducting polymer at microwave frequencies, the conducting polymer is incorporated with the $90^{\circ}$ hybrid coupler structure, and this proposed sensor operates as reflection type variable attenuator and variable phase shifter. The conducting polymer is employed as impedence-variable transmission lines that cause a impedance mismatching between the general transmission line and conducting polymer. The experiment was conducted with 100 ppm ethanol gas at temperature of $28^{\circ}C$ and relative humidity of 85 %. As a result, the amplitude deviation of $S_{21}$ is 0.13 dB and the frequency satisfying ${\angle}S_{21}=360^{\circ}$ is shifted about 2.875 MHz.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.15 no.2
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• pp.219-230
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• 2004

The purpose of this study is to improve the quality of white pan bread by adding polymannuronic acid, an excellent rheological properties material which has the high blood control function in seaweeds, to flour. To investigate the rheological properties appropriate to the making of white pan bread, amylograph, farinograph, extensography were done adding polymannuronic acid(0%, 1%, 3%, and 5%) to flour. The gelatinization condition between flour and compositic flour, amylogram was done. The result was that the gelatinization temperature in flour(100%) was $61.0^{\circ}C$, as polymannuronic acid rate was increased by 1%, 3%, 5%, thetemperature was all the same, $63.5^{\circ}C$. The maximum viscocity temperature of flour(100%) was $92.0^{\circ}C$. that of flour added polymannuronic acid (1%) $92.5^{\circ}C$, those of flour added polymannuronic acid (3%, 5%) unchangeable. $\alpha$ -amylase activity degree, maximum viscocity was that flour(100% was 525 BU, flour added polymannuronic acid (1%) 498 B.U, flour added polymannuronic acid (3%) 385B.U, flour added polymannuronic acid (5%) 360 B.U, highly decreased. Farinograph was done, as the additional quantity of polymannuronic acid increase(1%, 3%, 5%), water absorption rate increase much more thin the control. As the additional quantity of polymannuronic acid is added from 1% to 3%, development time of dough was increase, but one added 5% was decreased. In case of extensograph was done, resistance of dough increased but extensibility is decreased, so R/E value increased.