• Journal of Aquaculture
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• v.11 no.3
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• pp.371-380
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• 1998

This study has been conducted to develop the techniques for spat production of the sun and moon scallop from January 1995 to December 1996. With the adult scallops collected from the Sogwipo area, spawning induction and larvae rearing were attempted several times and monthly changes of GSI were also monitored during the experimental period. The results obtained wre as follows. 1. GSI started to increase from June and showed the maximum value of 22.17 and 14.98 in female and male respectively in November, and then gradually decreased from December. 2. Spawning induction by heating method turned out to the most efficient way showing the responding rate of 64.8~91.5%. The responding temperature was $21.4~26.4{\circ}C$ which was $3.1~8.5{\circ}C$ increased from the rearing temperature of $16.3~18.3{\circ}C$. An average number of eggs spawned was $9.2{\times}10^5$ 3. the average size of eggs after fertilization was about $72{\mu}m$ in diameter. The first polar body discharge, blastula formation, and trochopore larvae appearance occurred 30 mininutes, 18 hours, and 22 hours after fertilization respectively. 4. Settling rates in various collectors were similar one another, whereas pouring larvae in the mesh was the most efficient way for larval setting. 5. The spates grew to be 1mm in their shell length for the first 50 days after fertilization and 9.6mm in 135days. 6. Correlation between shell length (SL) of the spat and the number of days (X) after spat settlement could be expressed as $SL=257.75e ^{0.0272x}$(r=0.9100).

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.6
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• pp.709-734
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• 2001

The aims of this experiment were to investigate the strain and temperature changes simultaneously within autopolymerzing acrylic resin specimens. A computerized data acquisition system with an electrical resistance strain gauge and a thermocouple was used over time periods up to 180 minutes. The overall strain kinetics, the effects of stress relaxation and additional heat supply during the polymerization were evaluated. Stone mold replicas with an inner butt-joint rectangular cavity ($40.0{\times}25.0mm$, 5.0mm in depth) were duplicated from a brass master mold. A strain gauge (AE-11-S50N-120-EC, CAS Inc., Korea) and a thermocouple were installed within the cavity, which had been connected to a personal computer and a precision signal conditioning amplifier (DA1600 Dynamic Strain Amplifier, CAS Inc., Korea) so that real-time recordings of both polymerization-induced strain and temperature changes were performed. After each of fresh resin mixture was poured into the mold replica, data recording was done up to 180 minutes with three-second interval. Each of two poly(methyl methacrylate) products (Duralay, Vertex) and a vinyl ethyl methacrylate product (Snap) was examined repeatedly ten times. Additionally, removal procedures were done after 15, 30 and 60 minutes from the start of mixing to evaluate the effect of stress relaxation after deflasking. Six specimens for each of nine conditions were examined. After removal from the mold, the specimen continued bench-curing up to 180 minutes. Using a waterbath (Hanau Junior Curing Unit, Model No.76-0, Teledyne Hanau, New York, U.S.A.) with its temperature control maintained at $50^{\circ}C$, heat-soaking procedures with two different durations (15 and 45 minutes) were done to evaluate the effect of additional heat supply on the strain and temperature changes within the specimen during the polymerization. Five specimens for each of six conditions were examined. Within the parameters of this study the following results were drawn: 1. The mean shrinkage strains reached $-3095{\mu}{\epsilon},\;-1796{\mu}{\epsilon}$ and $-2959{\mu}{\epsilon}$ for Duralay, Snap and Vertex, respectively. The mean maximum temperature rise reached $56.7^{\circ}C,\;41.3^{\circ}C$ and $56.1^{\circ}C$ for Duralay, Snap, and Vertex, respectively. A vinyl ethyl methacrylate product (Snap) showed significantly less polymerization shrinkage strain (p<0.01) and significantly lower maximum temperature rise (p<0.01) than the other two poly(methyl methacrylate) products (Duralay, Vertex). 2. Mean maximum shrinkage rate for each resin was calculated to $-31.8{\mu}{\epsilon}/sec,\;-15.9{\mu}{\epsilon}/sec$ and $-31.8{\mu}{\epsilon}/sec$ for Duralay, Snap and Vertex, respectively. Snap showed significantly lower maximum shrinkage rate than Duralay and Vertex (p<0.01). 3. From the second experiment, some expansion was observed immediately after removal of specimen from the mold, and the amount of expansion increased as the removal time was delayed. For each removal time, Snap showed significantly less strain changes than the other two poly(methyl methacrylate) products (p<0.05). 4. During the external heat supply for the resins, higher maximum temperature rises were found. Meanwhile, the maximum shrinkage rates were not different from those of room temperature polymerizations. 5. From the third experiment, the external heat supply for the resins during polymerization could temporarily decrease or even reverse shrinkage strains of each material. But, shrinkage re-occurred in the linear nature after completion of heat supply. 6. Linear thermal expansion coefficients obtained from the end of heat supply continuing for an additional 5 minutes, showed that Snap exhibited significantly lower values than the other two poly(methyl methacrylate) products (p<0.01). Moreover, little difference was found between the mean linear thermal expansion coefficients obtained from two different heating durations (p>0.05).

• Horticultural Science & Technology
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• v.30 no.2
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• pp.129-136
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• 2012

This study was conducted to develop an efficient mass propagation method for the mature $Prunus$ $yedoensis$ Matsumura (43 to 58 years old). Cutting was conducted depending on cutting time, auxin treatments (IBA and NAA treatments mixed with talc powder), and cuttings position on shoots in a plastic house equipped with a fog system without heating. Rooted cuttings were transplanted to a nursery bed, and their growth characteristics were investigated in order to check whether the cuttings are successful or not for roadside tree planting. The average rooting rate was highly significant ($P$ < 0.0001) in all treatments: cutting on June 1st (61.4%) was more than two times greater in rooting rate than that on August 1st (23.6%); IBA 1,000 $mg{\cdot}L^{-1}$ (90.8%) and IBA 500 $mg{\cdot}L^{-1}$ (89.2%) showed much greater rooting rates than those of the other treatments; upper part of the cuttings treated with IBA 1,000 $mg{\cdot}L^{-1}$ showed the highest rooting rate, 96.7%. The interactions among treatments in the average rooting rate were also significant. There were significant differences ($P$ < 0.0001) among the auxin treatments in the survival rate of leafed cuttings transplanted to a nursery bed. The average survival rate was 46.5%, and IBA 1,000 $mg{\cdot}L^{-1}$ treatment was the highest in leafed cuttings 79.2%, but most of leafless cuttings were dead. There were significant differences ($P$ < 0.0001) among the cuttings, grafts, and in the seedlings height, diameter at root collar, the number of roots, branches, and leaves, etc., and the cuttings was the best. We can expect a possibility of mass propagation of improved $P.$ $yedoensis$ Matsumura and a high planting survival rate through the transplanting of cuttings to a nursery bed in which the cuttings should be the following conditions: cutting in June to July, use of the upper part of cuttings, IBA treatment, and rooting in August in a cutting-greenhouse equipped with a fog system.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.182-187
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• 2013

In closed plant production system like plant factory, changes in environmental factors should be identified for conducting efficient environmental control as well as predicting energy consumption. Since high relative humidity (RH) is essential for crop production in the plant factory, transpiration is closely related with RH and should be quantified. In this study, four varieties of lettuces (Lactuca sativa L.) were grown in a plant factory, and the leaf areas and transpiration rates of the plants according to DAT (day after transplanting) were measured. The coefficients of the simplified Penman-Monteith equation were calibrated in order to calculate the transpiration rate in the plant factory and the total amount of transpiration during cultivation period was predicted by simulation. The following model was used: $E_d=a*(1-e^{-k*LAI})*RAD_{in}+b*LAI*VPD_d$ (at daytime) and $E_n=b*LAI*VPD_n$ (at nighttime) for estimating transpiration of the lettuce in the plant factory. Leaf area and transpiration rate increased with DAT as exponential growth. Proportional relationship was obtained between leaf area and transpiration rate. Total amounts of transpiration of lettuces grown in plant factory could be obtained by the models with high $r^2$ values. The results indicated the simplified Penman-Monteith equation could be used to predict water requirements as well as heating and cooling loads required in plant factory system.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.106-117
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• 2012

Indirected heating dryer is used as one of the food waste treatment technologies for the production of the drier material supplied to the recycling facilities or end user. This study investigated the effect on drying efficiency for the operation of rotating screw with the circulating and falling movements on indirected drying process of food waste. The screw operating condition showed higher drying efficiency despite of the shorter drying time compared to the screw non-operating condition. The moisture content decreased to 14.4% from the initial moisture content of 77.1% after drying 5 hours in the screw operating condition. On the other hand, in the screw non-operating condition, the moisture content decreased slightly to 35.6% after drying 16 hours. During the drying process, variations of the water evaporation rate and particle size showed different tendencies depending on the moisture content regions. In the higher moisture content region above the glue zone(moisture content of about 50%-60%), the particle size increased and the water evaporation rate reached the highest peak. In the range of glue zone, the particle size maximized while the water evaporation rate decreased sharply. In the lower moisture content region below the glue zone, the water evaporation rate and particle size both decreased at the same time. The particle size distribution was widely ranged from 25.0mm to 0.25mm in the screw operating condition while it was narrowly distributed in the screw non-operating condition from 25.0mm to 3.56mm, especially highly concentrated to 25.0mm. It was regarded that the hygroscopic, capillary and gravitational water evaporated more easily from the intra-particle during the circulating and falling movement caused by the rotating of the screw and the difference of the cohesional force of water within intra-particle depending on the moisture content regions. Comparing the effect of the circulating and falling movement on drying efficiency, the water evaporation rates per time and per weight of dry solid in the screw operating condition were higher about 364% and 356%, respectively, than those of the screw non-operating condition.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.100-101
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• 2012

The plasma damage free and room temperature processedthin film deposition technology is essential for realization of various next generation organic microelectronic devices such as flexible AMOLED display, flexible OLED lighting, and organic photovoltaic cells because characteristics of fragile organic materials in the plasma process and low glass transition temperatures (Tg) of polymer substrate. In case of directly deposition of metal oxide thin films (including transparent conductive oxide (TCO) and amorphous oxide semiconductor (AOS)) on the organic layers, plasma damages against to the organic materials is fatal. This damage is believed to be originated mainly from high energy energetic particles during the sputtering process such as negative oxygen ions, reflected neutrals by reflection of plasma background gas at the target surface, sputtered atoms, bulk plasma ions, and secondary electrons. To solve this problem, we developed the NBAS (Neutral Beam Assisted Sputtering) process as a plasma damage free and room temperature processed sputtering technology. As a result, electro-optical properties of NBAS processed ITO thin film showed resistivity of $4.0{\times}10^{-4}{\Omega}{\cdot}m$ and high transmittance (>90% at 550 nm) with nano- crystalline structure at room temperature process. Furthermore, in the experiment result of directly deposition of TCO top anode on the inverted structure OLED cell, it is verified that NBAS TCO deposition process does not damages to the underlying organic layers. In case of deposition of transparent conductive oxide (TCO) thin film on the plastic polymer substrate, the room temperature processed sputtering coating of high quality TCO thin film is required. During the sputtering process with higher density plasma, the energetic particles contribute self supplying of activation & crystallization energy without any additional heating and post-annealing and forminga high quality TCO thin film. However, negative oxygen ions which generated from sputteringtarget surface by electron attachment are accelerated to high energy by induced cathode self-bias. Thus the high energy negative oxygen ions can lead to critical physical bombardment damages to forming oxide thin film and this effect does not recover in room temperature process without post thermal annealing. To salve the inherent limitation of plasma sputtering, we have been developed the Magnetic Field Shielded Sputtering (MFSS) process as the high quality oxide thin film deposition process at room temperature. The MFSS process is effectively eliminate or suppress the negative oxygen ions bombardment damage by the plasma limiter which composed permanent magnet array. As a result, electro-optical properties of MFSS processed ITO thin film (resistivity $3.9{\times}10^{-4}{\Omega}{\cdot}cm$, transmittance 95% at 550 nm) have approachedthose of a high temperature DC magnetron sputtering (DMS) ITO thin film were. Also, AOS (a-IGZO) TFTs fabricated by MFSS process without higher temperature post annealing showed very comparable electrical performance with those by DMS process with $400^{\circ}C$ post annealing. They are important to note that the bombardment of a negative oxygen ion which is accelerated by dc self-bias during rf sputtering could degrade the electrical performance of ITO electrodes and a-IGZO TFTs. Finally, we found that reduction of damage from the high energy negative oxygen ions bombardment drives improvement of crystalline structure in the ITO thin film and suppression of the sub-gab states in a-IGZO semiconductor thin film. For realization of organic flexible electronic devices based on plastic substrates, gas barrier coatings are required to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency flexible AMOLEDs needs an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}gm^{-2}day^{-1}$. The key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required (under ${\sim}10^{-6}gm^{-2}day^{-1}$) is the suppression of nano-sized defect sites and gas diffusion pathways among the grain boundaries. For formation of high quality single inorganic gas barrier layer, we developed high density nano-structured Al2O3 single gas barrier layer usinga NBAS process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nano- crystalline phase with various grain sizes in a single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the NBAS processed $Al_2O_3$ gas barrier film have improved order of magnitude compared with that of conventional $Al_2O_3$ layers made by the RF magnetron sputteringprocess under the same sputtering conditions; the WVTR of the NBAS processed $Al_2O_3$ gas barrier film was about $5{\times}10^{-6}g/m^2/day$ by just single layer.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1078-1086
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• 1996

The peroxo-polytungstic acid was formed by the direct reaction of tungsten powder with the hydrogen peroxide solution. Peroxo-polytungstic powder were prepared by rotary evaporator using the fabricated on to ITO coated glass as substrate by dip-coating method using $2g/10mL(W-IPA/H_2O)$ sol solution. A substrate was dipped into the sol solution and after a meniscus had settled, the substrate was withdrawn at a constant rate of the 3mm/sec. Thicker layer could be built up by repeated dipping/post-treatment 15 times cycles. The layers dried at the temperature of $65{\sim}70^{\circ}C$ during the withdrawn process, and then tungsten oxides thin film was formed by final heating treatment at the temperature of $230{\sim}240^{\circ}C$ for 30min. A linear rotation between the thickness of thin film and the number of dipping/post-treatment cycles for tungsten oxides thin films made by dip-coating was found. The thickness of thin film had $60{\AA}$ after one dipping. From the patterns of XRD, the structure of tungsten oxides thin film identified as amorphous one and from the photographs of SEM, the defects and the moderate cracks were observed on the tungsten oxides thin film, but the homogeneous surface of thin films were mostly appeared. The electrochemical characteristic of the $ITO/WO_3$ thin film electrode were confirmed by the cyclic voltammetry and the cathodic Tafel polaization method. The coloring bleaching processes were clearly repeated up to several hundreds cycles by multiple cyclic voltammetry, but the dissolved phenomenon of thin film revealed in $H_2SO_4$ solution was observed due to the decrease of the current densities. The diffusion coefficient was calculated from irreversible Randles-Sevick equation from the data obtained by the cyclic voltammetry with various scan rates.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.59-67
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• 1983

An experiment on the rearing of tilapia stocked in closed recirculating tanks eliminating biological filter beds was carried out at the Fish Culture Experiment Station of the National Fisheries University of Pusan, from May 18 through October 21, 1982, and the growth rates, feed conversion, water quality, spawning prevention and space utilization efficiency were discussed. Finally discussed is the feasibility on the establishment of commercial production units. On the water quality, the water temperature ranged from $22.8^{\circ}C\;to\;29.1^{\circ}C$, and total ammonia arround 10 ppm or slightly up. Maintaining phytoplankton bloom was not successful probably because of the active consumption by the heavily stocked tilapia. Several attempts were made by changing the culture water with green water from a nearby earthen pond with results of fading-away in a couple of days. Feed conversions were relatively high ranging from 0.9 to 1.2 except for experiment 1 when the fish were not fully recovered from weakened wintering state. The feed used was partly laboratory prepared $25\%$ protein diet and mostly commercially available $39\%$ protein carp feed. Spawning was completely controlled during the experiment, resulting from density effect, which ranged from 10kg to 40.7kg per square meter with water depth of 0.5 to 0.6m. Space utilization efficiency was very high. Daily net production from the experiment division 3, which showed the highest result, was 6.206 kg per tank, which is calculated 3,235 metric tons per hectare per year, This time, water temperature ranged from 27.8 to $29.1^{circ}C$, average being $28.4^{circ}C$, and total ammonia arround 10 ppm. An estimation for the commercial set-up of the production system based on the results of experiment divisions which had initial stocking rate $15\;kg/m^2$ or up, is made. If the total facility, 8 tanks comprising $56\;m^2$ in surface area, is used for the present study, the yield would become 5,639 kg from 200 day rearing, which would be possible under double sheets vinyl house without additional heating, and it is thought feasible in the economic view point, when 10 or more units are operated.

• Korean Chemical Engineering Research
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• v.50 no.3
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• pp.511-515
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• 2012

In this study, we used a commercial simulator to investigate the gasification characteristics of Roto coal in the partitioned fluidized-bed gasifier, which consists of 4 parts such as coal pyrolysis, char gasification, tar/oil gasification and char combustion. The heating medium was exchanged between the combustion part and the gasification part in order to supply the energy needed for pyrolysis and gasification. The correlation model from experimental data in relation to the reaction temperatures, the reaction gases and the coal feed rates was derived for the coal pyrolysis. The equilibrium model was used for the gasification and the combustion model for the char combustion. In order to compare the reaction behavior of the partitioned fluidized-bed gasifier, the single-bed gasifier was also simulated. The cold gas efficiency of both partitioned fluidized-bed gasifier and single-bed gasifier was almost the same. The $H_2$ and $CH_4$ contents of the syngas in the partitioned fluidized-bed gasifier slightly increased and the CO and $CO_2$ contents slightly decreased, compared with the singlebed gasifier. In order to verify the model, ten cases of the single-bed gasification experiment have been simulated. The contents of CO, $CO_2$, $CH_4$ in the syngas from the simulation corresponded with the experimental data while those of $H_2$ was slightly higher than experimental data, but the tendency of $H_2$ content in the syngas was similar to the experiments. In the coal conversion, the simulation results were higher than the experiments since equilibrium model was used for the gasification so that the residence time and contact time in the model is different from the experiments.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.51-56
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• 2015

The objective of this study was to evaluate the effect of silicate fertilizer on growth, physiology and abiotic stress tolerance of Chinese cabbage seedlings. Five silicate concentrations (8, 16, 32, 64, and 128mM) and control (non-treatment) were applied to Chinese cabbage seedlings twice a week. Three weeks after application of silicate treatment, seedlings were used for treating abiotic stresses and were assessed for growth and physiological characteristics. Growth parameters significantly increased in 8, 16, and 32mM treatments except 64 and 128mM. Total root surface area, total root length, and number of root tips increased in 8, 16 and 32mM treatments, but they decreased in treated seedlings with 64 and 128mM of silicate. The highest growth parameters and root morphology were observed in 8mM treatment. As for the effect on the seedling physiology, transpiration rates decreased while stomatal diffusive resistance increased to increasing silicate concentration. The application of silicate reduced the electrical conductivity, heating and chilling injury index at high and low temperatures. Silicate enhanced drought tolerance of Chinese seedlings by delaying the starting time of wilting point. The starting time of wilting point in the control was 3 days after discontinuation of irrigation, while in the 8, 64 and 128mM of silicate treatments were 4 days, and the 16 and 32mM treatments were 5 days. All plants were wilted after 5 days in control without irrigation whereas it showed in 8mM treatment after 6 days, in 16, 32, 64, 128mM treatments after 7 days.