• Journal of Aquaculture
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• v.18 no.4
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• pp.280-286
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• 2005

Experiments were conducted to examine the differences in ammonia removal rates with the different filter media between sand and zeolite, the expanding rates between $50\%$ and $100\%$, the water temperatures between $15^{\circ}C$ and $25^{\circ}C$, and the ammonia loading rates between 2 mg/L and 5 mg/L in the seawater fluidized bed filters system (FBF). The 2.1 m high FBF (8.3 cm diameter) consisted of the clear acrylic for the upper half and a PVC pipe for the lower half, Sand and zeolite were used as the filter media in sizes of 0.5$\pm$0.1mm. Each biofilter contained 5.4 L of media. The ammonia removal rates of the biofilter were higher at the $25^{\circ}C$ water temperature than those of the biofilter at $15^{\circ}C$ water temperature, and higher at the $50\%$ expanding rate of filter media than those of the biofilter at $100\%$ expanding rate of filter media. Also, the ammonia removal rates of FBF were higher at 5 mg/L ammonia concentration than those of FBF at 2 mg/L ammonia concentration in rearing water. With these better conditions the ammonia removal rates of FBF per day are practically acceptable and ranged ken 80.6 to $210.6g/m^3$.

• Journal of the Mineralogical Society of Korea
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• v.5 no.2
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• pp.61-71
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• 1992

Through the low-temperature(60-150${\circ}C$) hydrothermal treatment of perlite with the alkaline solution at various NaOH concentrations, the mode of volcanic glass alteration and resultant zeolite formation were investigated in a closed system. At a temperature of 80${\circ}C$ and alkalinities of pH range 8 to 12, corresponding to the natural environments of diagenetic zeolite formation, only weak dissolution of perlitic glass occurs without zeolite formation despite the residence time of 100 days. Activities of Si and Al increase progressively, as a consequence of increasing pH, whereas activity ratios of Si/Al decrease. Zeolites were synthesized from perlite in the alkaline solution at above 0.1M NaOH concentrations. Below the temperature of 100${\circ}C$ Na-P was mainly formed, whereas analcime was the dominant zeolite at the temperature range of 100-150${\circ}C$. During Na-P synthesis chabazite and Na-X were also formed as by-products in case of lower proportion of solution/sample(<10ml/g) and higher NaOH concentraion (>3M), respectively. The alteration modes of perlite in the zeolite synthesis reflect that the formation of synthetic zeolites occurs as an incongruent dissolution likely with the diagenetic formation of natural zeolites from volcanic glass. Considering much difference in reaction kinetics between natural and synthetic systems, however, the evaluated synthetic conditions in these experiments were not directly applicable to the natural diagenetic system.

• Journal of the Korean Solar Energy Society
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• v.35 no.4
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• pp.35-41
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• 2015

This study was conducted to develop a heat pump system to utilize waste heat within the greenhouse during the daytime in winter season. The system runs at 8 am to 6 pm for the heat storage operation, and from 6 pm to 8 am of the next day for the heat radiant work. In the case of the heat storage operation, the average solar radiation was $168.3W/m^2$ with $16.3^{\circ}C$ outside temperature. The $COP_s$ of the system shows 4.59 in this operation mode. When the temperature goes up to $18.6^{\circ}C$, the system $COP_s$ reached at 5.10. On the other hand, the $COP_h$ of the system in heat radiation mode shows 2.63. In this case, the inside of the greenhouse temperature was reaches at $24.7^{\circ}C$ when the outside temperature was $12.9^{\circ}C$.

• Bulletin of the Korean Mathematical Society
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• v.31 no.2
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• pp.167-172
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• 1994

For a given $C^{*}$-dynamical system (A, G, .alpha.) with a G-simple $C^{*}$-algebra A (that is A has no proper .alpha.-invariant ideal) many authors have studied the simplicity of a $C^{*}$-crossed product A $x_{\alpha{r}}$ G. In [1] topological freeness of an action is shown to guarantee the simplicity of the reduced $C^{*}$-crossed product A $x_{\alpha{r}}$ G when A is G-simple. In this paper we investigate the pure infiniteness of a simple $C^{*}$-crossed product A $x_{\alpha}$ G of a purely infinite simple $C^{*}$-algebra A and a topologically free action .alpha. of a finite group G, and find a sufficient condition in terms of the action on the spectrum of the multiplier algebra M(A) of A. Showing this we also prove that some extension of a topologically free action is still topologically free.

• Journal of Biomedical Engineering Research
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• v.11 no.2
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• pp.295-304
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• 1990

In order to use for artificial dental tooth (dental crowens) , new glass-ceramics material has been studied. Its basic composition and the condition of heat treatment for crystalization, mechanical and chemical properties were investigated. Adding of the LAS system composition in the basic glass, time and temperature for crystalization were shortened. Fracture toughness (kic)of samples heat treated at 90$0^{\circ}C$ for 2 hours is 2.5-2.6MN/m3/2, the optimum condition of heat treatment for artificial tooth is A and B samples heating to 75$0^{\circ}C$ for 2 hours, raising to 90$0^{\circ}C$ and maintaining at 90$0^{\circ}C$ for 2 hours and C sample heating to 75$0^{\circ}C$ maintaining at 75$0^{\circ}C$ for 2 hours. In acid and'alkali solution, chemical durability is excellent.

• Archives of Pharmacal Research
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• v.11 no.1
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• pp.7-13
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• 1988

The yeast cytochrome c gene has been recloned, and the resulting cytochrome c mRNA has been translated in rabbit reticulocyte lysate translation system. The newly synthesized apocytochrome c could be methylated by exogenously added cytochrome c-lysine N-methyltransferase. Enzymatic methylation of in vitro synthesized apocytochrome c was found to facilitate specifically its import into mitochondria of yeast, but not of rat liver.

• Journal of Animal Environmental Science
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• v.6 no.3
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• pp.169-174
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• 2000

TAO system was applied to treatment of piiggery slurry. In the experiments, the volume of influx was differentiated in four types. The features of operation, evaporation rate, and efficiency of successive treatment were drawn. The results are; 1. During the operation, the inside temperature was maintained at over $60^{\circ}C$ with the highest $70.2^{\circ}C$. 2. The evaporation rate of influx volume was 31.4%. And the evaporation volume of per square meter was $108{\;}\ell/\textrm{m}^2$; slightly different from $120{\;}\ell/\textrm{m}^2$ of batch type. 3. The VFAs was decreased by 95% (from $1,538lmg/{\ell}$ in influx to $72.9mg/{\ell}$ in Efflux). Thus, successive operation of TAO system is considered to be possible.

• Journal of Biosystems Engineering
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• v.19 no.3
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• pp.222-231
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• 1994

The efficient use of solar energy for greenhouse heating is one of the most obvious applications to save the heating energy for greenhouse culture. To increase the efficiency of solar energy utilization in plastic greenhouse, underground heat exchange system was installed. Characteristics of the stored and released thermal enery in plastic greenhouse with underground heat exchange system was analyzed. The average stored and released thermal energy in this system were 1,484 $kJ/m^2$ day and 555 $kJ/m^2$ day, respectively. The average coefficient of performance of heat exchange system was found to be 2.86. Also an attempt was made to predict the air temperature in plastic greenhouse. The agreement between the results of prediction and that of measurement was relatively good.

• Journal of Biosystems Engineering
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• v.36 no.5
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• pp.334-341
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• 2011

This study was conducted to compare the characteristics of heat dissipated from LED lamps with water cooling method and natural cooling method in a closed-type plant production system (CPPS) and to determine the optimum water temperature and flow rate for LED lamps with water cooling method. The experiments were performed in CPPS maintained at temperature of $24^{\circ}C$ and humidity of 70%. As compared to the LED lamps operated at water temperature of $22.5{\pm}1.2^{\circ}C$ and flow rate of $1,521{\pm}3.3\;mL{\cdot}min^{-1}$, air temperature under LED lamps with natural cooling was approximately increased by $1^{\circ}C$ and photosynthetic photon flux was decreased by $10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. PPF illuminated from LED lamps was affected by forward voltage varied by the surface temperature of LED lamps. Forward voltage of LED lamps was decreased with increasing surface temperature and then PPF was proportionately decreased. Five levels ($14^{\circ}C,\;17^{\circ}C,\;20^{\circ}C,\;23^{\circ}C,\;26^{\circ}C$) of water temperature and three levels ($500\;mL{\cdot}min^{-1}$, $1,000\;mL{\cdot}min^{-1}$, $1,500\;mL{\cdot}min^{-1}$) of flow rate were provided to analyze the change of surface temperature and heat exchange of LED lamps. Heat exchange was increased with decreasing water temperature and increasing flow rate. At flow rate of $1,000-1,500\;mL{\cdot}min^{-1}$ and water temperature of 22.0-$22.6^{\circ}C$, surface temperature of LED lamps can be approached to $24^{\circ}C$ that was almost same as air temperature in CPPS. The calorific value generated from LED lamps used in the study was estimated to be $103.0\;kJ{\cdot}h^{-1}$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.11
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• pp.1470-1476
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• 2020

This paper describes a design of a lightweight security system-on-chip (SoC) suitable for the implementation of security protocols for IoT and mobile devices. The security SoC using Cortex-M0 as a CPU integrates hardware crypto engines including an elliptic curve cryptography (ECC) core, a SHA3 hash core, an ARIA-AES block cipher core and a true random number generator (TRNG) core. The ECC core was designed to support twenty elliptic curves over both prime field and binary field defined in the SEC2, and was based on a word-based Montgomery multiplier in which the partial product generations/additions and modular reductions are processed in a sub-pipelining manner. The H/W-S/W co-operation for elliptic curve digital signature algorithm (EC-DSA) protocol was demonstrated by implementing the security SoC on a Cyclone-5 FPGA device. The security SoC, synthesized with a 65-nm CMOS cell library, occupies 193,312 gate equivalents (GEs) and 84 kbytes of RAM.