• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.2
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• pp.947-953
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• 2012

In this study we investigated the manufacturing method for the activated carbon using the char from the pyrolysis of waste tire. The physical activation method using the steam in the fixed-bed quartz reactor was used for preparation of activated carbon. The primary experiment parameters are the activation temperature, activation time, heating rate, and the injection quantity of active agent. From the results of pore distribution of activated carbon, the micropore which was made in $850^{\circ}C$ of activation temperature, $5^{\circ}C$/min of heating rate, and 3 hours of activation time was developed in biggest quantity, and mesopore and macropore were developed in the biggest quantity too. The optimum conditions for producing the activated carbon using the pyrolysis residue were $850^{\circ}C$ of activation temperature, 3 hours of activation time, $5^{\circ}C$/min of heating rate, and 3 g $H_2O/char-g{\cdot}hr$ of active agent through this study. The produced activated carbon in these conditions showed that the potentiality of utilization as activated carbon because the BET specific surface area was $517.6m^2/g$ and total pore volume was $0.648cm^3/g$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.32-38
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• 2020

This study summarizes test methods and evaluation methods for examining the thermal characteristics of Jeju-type ground heat exchangers (GHXs) installed on Jeju Island, and analyzes the ground temperature and thermal characteristics of ground heat exchangers installed in various regions by using thermal response tests (TRT). Jeju Island is composed of volcanic rock layers, and the groundwater flow is well developed. A Jeju-type GHX can be installed up to 30 m from groundwater level after drilling a borehole. The ground heat exchanger has a structure in which several pipes are inserted into the borehole. In order to examine the characteristics of the Jeju-type GHX, tests were conducted on ground heat exchangers installed in four places on Jeju Island (Pyoseon, Jeju, Namwon, and Hallym). As a result of the analysis of the Jeju-type ground heat exchanger, the ground circulating water temperature stabilized according to the heat injection, depending on the installed location, and was formed within one to three hours. The ground heat exchanger capacity in Hallym was highest at 73.4 kW (cooling) and 82.8 kW (heating), and the Jeju-type calculation was lowest at 34.1 kW (cooling) and 23.3 kW (heating).

• Tunnel and Underground Space
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• v.23 no.4
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• pp.297-307
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• 2013

In this study, the thermal analysis is carried out for a result of borehole heater test using ABAQUS ver 6.10 based on finite element analysis code. Thermal-mechanical rock properties as determined by laboratory tests before the in situ test and characteristics of the atmosphere at the test section are used as the initial condition. When comparing the results of the in situ test and thermal analysis, the temperature of C3 observation hole that is 0.9 m away from the heater showed very similar patterns and figures (about $1.3^{\circ}C$ difference). But the results of the A and B observation hole showed a significant difference around $15^{\circ}C{\sim}20^{\circ}C$. To find the reason for these results, the over-coring is carried out for the A1 and B1 observation holes. As a result of checking the excavated rock core with the naked eye, there is no problem on the number and position of the sensor as the test plan. However the state of cement injection in the observation hole is poor.

• Journal of Food Hygiene and Safety
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• v.4 no.2
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• pp.103-108
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• 1989

Three mushroom cannerries were selected by size which are representative vegetable processing firms in korea for monitoring microbial contamination of processing water, washing water, mushroom before and after washing through first and second washing tanks and, blanched and prolonged mushroom for certain time at room temperature. Total contamination degree was expressed as colony forming unit (CFU) of mesophilic aerobes. The contamination degree of processing water was $10^{2}\;CFU/100\;ml$ and washing water in first and second washing tank were 10 to 100 times higher than processing water. When 2.3 tons of washing water was used for washing 1 ton of mushroom, washing effect was showed by reduction of microbial load but cutting it to 1.8 tonsIl ton of mushroom, microbial load was higher than that of raw mushroom level. Blanching reduced microbial load to 50-500 CFU/g of blanched mushroom and it was not seen much increase of CFU in blanched mushroom left at room temperature for 3 hours in $16^{\circ}C$ processing water. Just after injection of $80^{\circ}C$ brine in container, CFU/ml of brine in container was $84{\times}10^{4}$ but it was increased rapidly to $20{\times}10^{7}$ after 2 hours at ambient temperature.

• Journal of Nutrition and Health
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• v.36 no.2
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• pp.133-146
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• 2003

This study was performed to investigate the in vitro and in vivo anticancer effects of persimmon leaf extracts on human gastric cancer cells. In vitro anticancer effects of persimmon leaf extracts (water extract at 8$0^{\circ}C$ for 3 hours, water extract at room temperature for 48 hours, 50% ethanol extract at 8$0^{\circ}C$ for 3 hours, 50% ethanol extract at room temperature for 48 hours, 75% ethanol extract at 8$0^{\circ}C$ for 3 hours and 75% ethanol extract at room temperature for 48 hours) on SNU16 (Korean gastric cancer cell) were investigated by MTT assay. Persimmon leaf extracts exhibited strong in vitro anticancer effects. We found that the higher the ethanol content of the solvent, the stronger the in vitro anticancer effects. Extraction yields, contents of flavonoids, vitamin A, vitamin C and vitamin E were measured. We found that the higher the ethanol content of the solvent, the higher the extraction yields and the contents of flavonoids, vitamin A and vitamin E. Among persimmon leaf extracts, 75% ethanol 8$0^{\circ}C$ extract showed the highest extraction yield, the highest contents of flavonoids, vitamin A and vitamin E and exhibitied the strongest in vitro anticancer effect on SNU16. Therefore, 75% ethanol 8$0^{\circ}C$ extract was chosen as the material to investigate in vivo anticancer effects. In vivo anticancer effect of persimmon leaf 75% ethanol 8$0^{\circ}C$ extract was investigated in SNU16 transplanted nude mice. Twenty five female nude mice (BALB/c) were blocked into five groups according to body weight and raised for 4 weeks with diets containing 4% (w/w), 8% (w/w) persimmon leaf 75% ethanol 8$0^{\circ}C$ extract, with IT (intratumoral) injection treatment with 1.65 mg/100 $\mu$1, 3.3 mg/100 $\mu$1 concentration every other day 3 weeks after SNU16 was transplanted. Persimmon 75% ethanol 8$0^{\circ}C$ extract significantly lowered tumor weight and tumor volume in SNU16 transplanted nude mice. Tumor weight and tumor volume in all experimental groups were significantly lower than those in the control group. Helper T cell (CD4) levels of mice injected with 3.3 mg/100 $\mu$1 extract significantly increased. Cytotoxic T cell (CD8) levels in all experimental groups significantly increased and helper/cytotoxic T cell ratios in all experimental groups significantly decreased. Natural killer cell and MHC class II molecule in all experimental groups significantly increased. In conclusion, persimmon leaf 75% ethanol 8$0^{\circ}C$ extract exhibited strong in vitro and in vivo anticancer effects against SNU16 cells and it increased cytotoxic T cell, natural killer cell and MHC classII molecule in experimental groups in SNU16 transplanted nude mice.

• Resources Recycling
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• v.12 no.4
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• pp.20-29
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• 2003

In order to efficiently recycle the waste solution resulting from shadow mask processing, nano-sized Ni-ferrite powder was fab-ricated through spray pyrolysis process. The average particle size of the powder was below 100nm. In this study, the effects of the reaction temperature. the concentration of raw material solution and the injection speed of solution on the properties of powder were respectively investigated. As the reaction temperature increased from $800^{\circ}C$ to $1100^{\circ}C$, average particle size of the powder significantly Increased and power structure became more solid, whereat its specific surface area was greatly reduced. Formation rate and crystallization of($NiFe_2$$O_4$) phale increased along with the temperature rise. As the concentrations of iron and nickel components in wastere solution increased, particle size of the powder became larger, particle size distribution became more irregular, and specific surface area was reduced. Formation rate and crystallization of $NiFe_2$$O_4$ phase increased significantly along with the increase of the concentration of solution. As the inlet speed of solution increased, particle size of the powder became larger, particle size distribution became wider, specific surface area was reduced and powder structure became less solid. As the inlet speed of solution decreased, formation rate and crystallization of $NiFe_2$$O_4$ phase significantly increased.

• Journal of the Microelectronics and Packaging Society
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• v.13 no.4
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• pp.51-56
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• 2006

Polymer light emitting diodes (PLEDs) with ITO/EDOT:PSS/PVK/PFO-poss/LiF/Al structures were prepared by the spin coating method on ITO(indium tin oxide)/glass substrates. PFO-poss[Poly(9,9-dioctylfluorenyl-2,7-diyl) end capped with poss] was used as light emitting polymer. PVK[poly(N-vinyl carbazole)] and PEDOT:PSS [poly(3,4-ethylenedioxythiophene):poly(styrene sulfolnate)] polymers were used as the hole injection and transport materials. The effect of PFO-poss concentration and the heating temperatures on the electrical and optical properties of the devices were investigated. At the same concentration of PFO-poss solution, the current density and luminance of PLED device tend to increase as the annealing temperature increase from $100^{\circ}C$ to $200^{\circ}C$. The maximum luminance was found to be about 958 cd/m2 at 13V for the PLED device with 1.0 wt% PFO-poss at the annealing temperature of $200^{\circ}C$. In addition, the PLED device showed bluish white emission through the strong greenish peak with 523 nm in wavelength. As the concentration of PFO-poss increase from 0.5 wt% to 1.0 wt% and temperature of PLEDs increase from $100^{\circ}C$ to $200^{\circ}C$, the emission color tend to be shifted from blue with (x, y) = (0.17,0.14) to bluish white with (x, y) : (0.29,0.41) in CIE color coordinate.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.685-690
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• 2014

The treatment of combined sewer overflow (CSO) is one of potential concerns in domestic wastewater treatment in Korea due to the pre-announce of CSO regulations. This work investigated the effects of disinfectant (NaOCl) concentration (0.11 to 4.0 mg $Cl_2/L$), pH (6.5 to 8.0), temperature (15 to $25^{\circ}C$), ammonia (10 to 41 mg N/L), and suspended solids (91 to 271 mg SS/L) on the chlorine disinfection of CSO. The effect of NaOCl concentration on the pseudo-$1^{st}$ order reaction rate for total coliform inactivation was described well with a saturation-type model with the half-velocity constant of 1.212 mg/L. The total coliform inactivation reaction rate decreased with SS and pH, and increased with temperature. Ammonia in the examined range did not affect the disinfection kinetics. A chlorine contact tank with the injection chlorine level of 1 mg $Cl_2/L$ and the hydraulic retention time of 1.25 min is estimated to reduce total coliform from $1{\times}10^5MPN/mL$ to 1,000 MPN/mL at 271 mg SS/L, $15^{\circ}C$, and pH 8.0. Chlorine would be a proper option for the disinfection of CSO.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.3
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• pp.93-98
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• 2005

The crystal growth of calcite at a low temperature range was carried out by the hydrothermal method using amorphous calcium carbonate which has excellent solubility in water. Amorphous calcium carbonate was prepared by the wet chemical reaction of a stoichiometric mixture of $CaCl_2\;and\;Na_2CO_3$. An important factor was the reaction temperature and time taken in preparation of the amorphous calcium carbonate. From the solubility results calculated by the weight loss method, $NH_4NO_3$ solutions were found to be the most promising solvents to grow calcite single crystals. The hydrothermal conditions for high growth rates of calcite single crystals were as follows: starting material: amorphous calcium carbonate, solvent: 0.01 m $NH_4NO_3$, temperature: $180^{\circ}C$, duration: 30 days. And properties of calcite single crystals were follows: dislocation density: $10^6{\sim}10cm^{-2}$, UV-visible transmittance: about 80% from 190 to 400 nm and birefringence: $0.17{\sim}0.18$. Also, it can be known from the FT-IR results that the absorption peak by injection of $HCO_3^-\;and\;OH^-$ ions was not shown.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.922-930
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• 2008

The selective non-catalytic reduction(SNCR) performance is sensitive to the process parameters such as flow velocity, reaction temperature and mixing of reagent(ammonia or urea) with the flue gases. Therefore, the knowledge of the velocity field, temperature field and species concentration distribution is crucial for the design and operation of an effective SNCR injection system. In this work, a full-scale two-dimensional computational fluid dynamics(CFD)-based reacting model involving a droplet model is built and validated with the data obtained from a pilot-scale urea-based SNCR reactor installed with a 150 kW LPG burner. The kinetic mechanism with seven reactions for nitrogen oxides($NO_x$) reduction by urea-water solution is used to predict $NO_x$ reduction and ammonia slip. Using the turbulent reacting flow CFD model involving the discrete droplet phase, the CFD simulation results show maximum 20% difference from the experimental data for NO reduction. For $NH_3$ slip, the simulation results have a similar tendency with the experimental data with regard to the temperature and the normalized stoichiometric ratio(NSR).