• Journal of Wetlands Research
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• v.17 no.1
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• pp.62-74
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• 2015

Urban areas are variously under threat including deterioration of ecological functions. Many pond wetland types have been created as part of an effort to improve and restore this urban environment. This study was arranged to examine improvement plans of wetlands in urban areas by analyzing semi-natural wetlands in farm areas. As for environment for water quality, it suggested the inflow of natural water neighboring rivers or the direct inflow of rain as the improvement plans. The result which analyzed soil pH, OM, and T-N content of the soil environment mentioned that urban areas supplied artificial sluices, removed apoptotic bodies, and used artificial soil and waterproofing materials and use of natural materials in design and construction, the sluice state of the natural form, and negligence of autumn plants were suggested as the improvement plans. Florae appeared in the subject sites of the study have found that there are 35 families 69 species in urban areas and 53 families 142 species in rural areas. As the average has found that there are 18.5 families 29.3 species in 4 urban areas and 26.3 families 53.5 species in 4 rural areas, the big difference between them was analyzed. As the cause has found that there are differences in yearly plants in farming areas when compared to urban areas, creation of various basic environments including soil and water quality was suggested to make yearly plants settle down widely. Naturalized plants have found that there are no big differences between urban areas and rural areas. However, the average of the naturalized ratio in urban areas is 17.4% as the naturalized plants are about 1/4 of the appeared plants. As it was analyzed to be higher than 7.7%, the average of the naturalized ratio in farming areas as the big difference, creation of various inhabiting environments was suggested to make more yearly plants appear like the analyzed result of the life type. Consideration of placement, materials, and inhabiting environments was suggested to make creation of wetlands well appreciated to improve functions of wetlands in urban areas. It is expected that the above results of the study will be utilized in creation and improvement of the pond wetlands which can play a huge role in increase and improvement of biological diversity in urban areas.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.103-110
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• 2018

This study was conducted to investigate the optimum irrigation method for propagation of cutting strawberry ($Fragaria{\times}ananassa$ Duch. cv. Maehyang) plantlet in summer season. The cutting strawberry plantlets were planted in 24-cell tray ($60{\times}34{\times}10cm$) filled with commercial mixed medium (Tosilee) and placed in semi closed-type small plastic tunnel. Each semi closed-type small plastic tunnel was treated as follows; control (non-treatment), over head irrigation (twice a day), capillary mats irrigation (twice a day), or fog irrigation (30 minutes turn on and 10 minutes off from 8:00 to 18:00). The strawberry plantlets were rooted during 8 days in the semi closed-type small plastic tunnel, and then plastic film was removed. Growth parameters, such as plant height, root length, number of primary roots, petiole length, leaf length, leaf width, crown diameter, SPAD, leaf area, fresh and dry weights of the shoot and root, were measured at 61 days after cutting. Relative humidity in tunnel was high in the order by fog irrigation, over head irrigation, capillary mats, and the control as 72.5, 56.3, 45.8, and 29% on average, respectively. However, the air temperature was similar in all treatments. On the 4 and 8 days, the rooting rate of strawberry plantlet was significantly higher in the over head irrigation and fog irrigation treatments. Plant height, petiole length, crown diameter, and leaf area were highest in the over head irrigation and fog irrigation treatments. In addition, fresh and dry weights of shoot were greater in over head irrigation and fog irrigation treatments than the others. Dry weight of root was differed significantly heaviest in the fog irrigation treatment. However, root length, no. of primary roots, SPAD value, and fresh weight of root were not significantly different in all treatments. These results indicated that growth and rooting for propagation of cutting strawberry plantlet 'Maehyang' were best achievement in the over head irrigation and fog irrigation treatments.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.826-833
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• 2014

Driven by both environmental and economic reasons, the development of small to medium scale GTL(gas-to-liquid) process for offshore applications and for utilizing other stranded or associated gas has recently been studied increasingly. Microchannel GTL reactors have been prefrered over the conventional GTL reactors for such applications, due to its compactness, and additional advantages of small heat and mass transfer distance desired for high heat transfer performance and reactor conversion. In this work, multi-microchannel reactor was simulated by using commercial CFD code, ANSYS FLUENT, to study the geometric effect of the microchannels on the heat transfer phenomena. A heat generation curve was first calculated by modeling a Fischer-Tropsch reaction in a single-microchannel reactor model using Matlab-ASPEN integration platform. The calculated heat generation curve was implemented to the CFD model. Four design variables based on the microchannel geometry namely coolant channel width, coolant channel height, coolant channel to process channel distance, and coolant channel to coolant channel distance, were selected for calculating three dependent variables namely, heat flux, maximum temperature of coolant channel, and maximum temperature of process channel. The simulation results were visualized to understand the effects of the design variables on the dependent variables. Heat flux and maximum temperature of cooling channel and process channel were found to be increasing when coolant channel width and height were decreased. Coolant channel to process channel distance was found to have no effect on the heat transfer phenomena. Finally, total heat flux was found to be increasing and maximum coolant channel temperature to be decreasing when coolant channel to coolant channel distance was decreased. Using the qualitative trend revealed from the present study, an appropriate process channel and coolant channel geometry along with the distance between the adjacent channels can be recommended for a microchannel reactor that meet a desired reactor performance on heat transfer phenomena and hence reactor conversion of a Fischer-Tropsch microchannel reactor.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.75-80
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• 1999

A field experiment was carried out to determine the optimum application level of dicamba herbicide for efficient control of Abutilon avicennae in silage corn field. Five treatments of application levels (0 ; control, $0.75{\ell},\;1.0{\ell},\;1.25{\ell}\;and\;1.5{\ell}$) were arranged at National Livestock Research Institute, RDA, Suwon in 1995 and 1996. The hybrid silage corn was P 3352 and dicamba herbicide was applied at 5~6 leaf stage of corn. The growth of corn was poor in control plot, and the days for tasseling and silking were delayed 2~3 days when compared with the plots of herbicide application. The control efficiency of Abutilon avicennae was excellent as 94.7~98.1% in the plots of dicamba application. A slight injury of herbicide was observed at early stage of corn when applied at $1.0{\ell},\;1.25{\ell}\;and\;1.5{\ell}$ of dicamba per ha. Forage dry matter(DM) yield, length and weight of ear in the plots of dicamba treatments were significantly higher than those of control. The DM yield of control(12,070kg/ha) was only 64.2~66.9% of dicamba treatment plot(18,050~18,795kg/ha). However, there was no yield difference among dicamba application level. The percentage of ear to total DM yield was ranged from 53.4 to 56.8%. The nutritive value(crude protein, ADF, NDF, digestibility and TDN) was very similar among all treatments. From the above results, it is recommended that optimum application level of dicamba herbicide was $0.75{\sim}1.0{\ell}/ha$ for efficient control of Abutilon avicennae and for silage corn production without herbicide injury.

• Analytical Science and Technology
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• v.28 no.6
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• pp.453-459
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• 2015

Split-flow thin cell fractionation (SPLITT fractionation, SF) is a particle separation technique that allows continuous (and thus a preparative scale) separation into two subpopulations based on the particle size or the density. In SF, there are two basic performance parameters. One is the throughput (TP), which was defined as the amount of sample that can be processed in a unit time period. Another is the fractionation efficiency (FE), which was defined as the number % of particles that have the size predicted by theory. Full-feed depletion mode (FFD-SF) have only one inlet for the sample feed, and the channel is equipped with a flow stream splitter only at the outlet in SF mode. In conventional FFD-mode, it was difficult to extend channel due to splitter in channel. So, we use large scale splitter-less FFD-SF to increase TP from increase channel scale. In this study, a FFD-SF channel was developed for a large-scale fractionation, which has no flow stream splitters (‘splitter less’), and then was tested for optimum TP and FE by varying the sample concentration and the flow rates at the inlet and outlet of the channel. Polyurethane (PU) latex beads having two different size distribution (about 3~7 µm, and about 2~30 µm) were used for the test. The sample concentration was varied from 0.2 to 0.8% (wt/vol). The channel flow rate was varied from 70, 100, 120 and 160 mL/min. The fractionated particles were monitored by optical microscopy (OM). The sample recovery was determined by collecting the particles on a 0.1 µm membrane filter. Accumulation of relatively large micron sized particles in channel could be prevented by feeding carrier liquid. It was found that, in order to achieve effective TP, the concentration of sample should be at higher than 0.4%.

• The korean journal of orthodontics
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• v.29 no.5 s.76
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• pp.613-625
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• 1999

The purpose of this study was to compare the bracket shear bond strengths of the crystal growth solutions with those of the $37\%$ phosphric acid etch technique. The 4 crystal growth solutions were made experimentally in the lab, that is, (1) $30\%$ polyacrylic acid solution containing 0.3 M sulfuric acid (ES 1), (2) $30\%$ polyacrylic acid solution containing 0.6M sulfuric acid (ES 2), (3) $30\%$ polyacrylic acid solution containing 0.3 M sulfuric acid and 0.6 M lithium sulfate(ES 3), and (4) $30\%$ polyacrlic acid solution containing 0.3 M sulfuric acid and $5\%$ phosphoric acid(ES4). The $37\%$ phosphoric acid solution used as a control. Bovine lower incisor tooth enamel was treated by the above solutions for 60 sec, washed out for 20 sec with slow water stream, and bonded lower anterior edgewise bracket with the light curing orthodontic composite resin adhesives. The teeth bonded brackets were stored in the distilled water at room temperature for 24 h, and followed to test the bracket shear bond strength. The acid etch technque showed 177.6 kg/$cm^2$ of mean shear bond strength which was the highest among the enamel treatment solutions. ES 1 shown 58.4 kg/$cm^2$ of mean shear bond strength and that of ES 4 showed 66.5 kg/$cm^2$. There was no significant difference between the two(p>0.05). ES2 showed 110.6kg/$cm^2$ of mean shear bond strength which was $62.3\%$ of that of acid etch technique. ES 3 showed 131.1 kg/$cm^2$ of mean shear bond strength which was the highest among experimental crystal growth solutions and which was $74\%$ of that of acid etch technique. The shear bond strengths of the crystal growth solutions were significantly lower that that of acid etch technique(p<0.05). The results sugest that although bracket shear bond strength of $30\%$ polyacrylic acid solution containing 0.3M sulfuric acid and 0.6 M lithium sulfate were showed the highest, it is low for the clinical application of this solution.

• Journal of Embryo Transfer
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• v.19 no.2
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• pp.81-87
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• 2004

This study was designed to determine whether repeated superovulation is beneficial for recovery and quality of oocytes in Korean native goats. Seventy-six mature goats, maintained in a pen under natural day length and fed hay ad libitum, were pretreated with progestagen impregnated CIDR for 10 days and then the goats were divided into two groups. One group of the goats received a single intramuscular injection of 1,000 IU PMSG on Day 8 of CIDR insertion. The other group of the goats received twice daily intramuscular injections of a total of 70 mg FSH for 3 days from Day 8 of CIDR. All the gonadotropin treated goats were injected with 10 mg $PGF2{\alpha}on$ Day 8 and 400 IU hCG in the afternoon on Day 10. For oocyte recovery, donor goats were fasted 24 h before operation. Anesthesia was induced by intravenous injection of 2% xylazine(0.2 mg/kg body weight) and ketamin(11 mg/kg body weight). In vivo oocytes were recovered by follicle aspiration or oviduct flushing at 35 to 40 hours after hCG injection through mid-ventral incision. The mean number of CL and oocytes recovered and recovery rate of oocytes by oviduct flushing were greater(P<0.05) in the first treatment than those in the second treatment. Contrary to our assumption, PMSG treatment significantly (P<0.05) increased the number of CL formed and recovery rate of oocytes compared to FSH. However, the same effect was not observed in recovery of follicular oocytes. There was no significant difference in oocyte quality between FSH and PMSG or first and second treatments. The present results indicate that repeated superovulation and repeated use of donor animals may be inefficient for obtaining oocytes in good qualities.

• Journal of Embryo Transfer
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• v.19 no.2
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• pp.113-119
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• 2004

The purpose of the present study was to examine whether collection time affects results of oocyte recovery from superovulated goats. Fiftyty-one mature Korean native goats, maintained in a pen under natural day length and fed hay ad libitum, were pretreated with progestagen impregnated CIDR for 10 days and then the goats were divided into two groups. One group of the goats received a single intramuscular injection of 1,000 IU PMSG on Day 8 of CIDR insertion. The other group of the goats received twice daily intramuscular injections of a total of 70 mg FSH for 3 days from Day 8 of CIDR. All the gonadotropin treated goats were injected with 10 mg $PGF_{2\alpha}$ on Day 8 and 400 IU hCG in the afternoon on Day 10. For oocyte recovery, donor goats were fasted 24 h before operation. Anesthesia was induced by intravenous injection of 2% xylazine(0.2 mg/kg body weight) and ketamin(11 mg/kg body weight). In vivo oocytes were recovered by follicle aspiration or oviduct flushing at 29 to 34, 35 to 40 and 41 to 50 h after hCG injection through mid-ventral incision. There was no significant difference in the mean number of CL and oocytes recovered. Oocyte collection at 29 to 40 h after hCG increased(P<0.05) the recovery rate of ovulated oocytes in oviducts compared to 41 to 50 h. The same results were also observed in the recovery of follicular oocytes. Oocyte grade was not affected by collection time. When oocytes were collected from follicular oocytes at 41 to 50 h after hCG, the recovery rate of Grade II oocytes was the lowest(P<0.05). From these results, it is suggested that oocyte recovery at 35 to 40 h after hCG will be successful for further use.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.25 no.4
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• pp.281-294
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• 1999

Vasospasm causes microvascular surgery to fail as a main factor in the loss of transferred flap dye to the diminution of blood flow in reconstruction surgery. Although there has been extensive research to resolve the vasospasm problem, no one has reached an ideal solution to date. However, cryotherapy, which is often used for destruction of tumor lesions, is being presented as a new way of releasing vasospasm. After making a histomorphometric measurement on vasodialation during the course of 1, 3 and 7 days, 2 and 4 weeks, and 5 months periods and observing the change of blood vessel in a histologic, immunohistochemical, and scanning electronic microscopic approach, the results were as follows : 1. Vascular inner diameters of the experimental 1 and 3 days groups were measured $476.3{\pm}28.20{\mu}m$, $497.15{\pm}48.79{\mu}m$ respectively showing statistically meaningful vasodilation(P<0.05), which continued by the experiment 4 weeks group. However, in the experimental 5 months group, the vascular inner diameter appeared similar to the control groups. Even though the thickness of smooth muscular layers come out to be thinner in all the experimental groups compared to the control group, it was difficult to find any statistical meaningfulness. In addition, the vascular external diameters of every experimental groups were shown to be longer than the control group. 2. In light microscopic view, severe injury was evident on the smooth muscular layer cell from the experimental 1 day group, started recovering partially from the experimental 7 days group, and was mostly restored in the experimental 4 weeks group and layer of adventitial stripping were nearly recoverd 2 weeks group. 3. The PCNA positive cells of smooth muscular layer were observed from the experimental 7 days group and had a tendency to increase by the experimental 2 weeks group. In the experimental 4 weeks and 5 months group, the number of PCNA possitive cells observed was comparable to the control group. 4. ${\alpha}$-SMA level of smooth muscular layer cells, having been significantly lower than the control group in the severly damaged experimental 1 day group. It was seen to be increased in the experimental 7 days group and turned out to show similar ${\alpha}$-SMA level in 4 weeks to the control group. 5. In the view of SEM, the endothelial cells were destructed and falling off, and also present the appearance of flattening in the experiment 1 day group. The endothelial layer cells started partially recovering from the 7 days group after the freezing injury. On 4 weeks and 5 months, the endothelial cells were fully coverd the damaged area, also it's appearance is similar to control group. In conclusion, the vascular freezing after the removal of adventitia caused damages to smooth muscular layer cells, and brought about vasodilation, which continued by the 4th week. The smooth muscular layer cells started partially reviving from the 7rd day after the damage by vascular freezing, and recovered their similar figure to the control group's 4 weeks later. This was considered the result of cells which surround the damaged blood vessel being influxed into the smooth muscular layers. Therefore, this local freezing injury on the blood vessel was thought to be applied clinically to relieve severe vasospasm which cannot be treated by vasodilation drug, a microvascular surgery.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.625-641
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• 2003

Background: This study presents a biomechanical and histometric comparison of bone response to implants with various area of hydroxyapatite(HA) coating. Methods: The implants were placed in the tibia of 10 rabbits weighing 2.5-3.5kg. The control group had a machined surface, the experimental group 1 had 50${\mu}m$ thick HA coated in a band form, and the experimental group 2 had 50${\mu}m$ thick HA coated on the entire surface. 8 weeks after implantation, the animals were sacrificed. Removal torque was measured and histologic preparation was also performed for histologic and histometric analysis. Bone to implant contact as well as percentage of bone area inside threads were measured. ANOVA post hoc, and t-test were used for statistical analysis with p-value p<0.05. Results: 1. The removal torques were 9.36${\pm}$5.64 Ncm, 48.40 ${\pm}$ 16.66 Ncm, and 82.37${\pm}$22.56 Ncm for the control, exp. 1, and exp. 2 group respectively. Statistically significant difference were found among all the groups(p<0.05). 2. Bone to implant contact in the cortical bone were 38.94${\pm}$10.9 %, 66.90${\pm}$14.1 %, 73.00${\pm}$19.4 %, in the marrow bone, 8.30${\pm}$5.4%, 14.59${\pm}$5.9%, 18.54${\pm}$11.8%, and in total, 22.40${\pm}$10.1%, 31,17${\pm}$7.5%, 41.41${\pm}$12.2% for the control, exp. 1, and exp. 2 group respectively . In the cortical bone, exp. 1, and exp. 2 group showed statistically significantly higher contact compared to control group. Total contact and in the marrow bone, only exp. 2 group showed statistically significantly higher contact compared to control group(p<0.05). In all the groups significantly higher contact were observed in the cortical bone compared to the marrow bone(p<0.05). 3. Percentage of bone area inside threads in the cortical bone were 55.68${\pm}$7.25%, 55.19${\pm}$13.19%, 57.04${\pm}$13.33%, in the marrow bone, 12.34${\pm}$14.61%, 17.56${\pm}$20.04%, 20.26${\pm}$12.83%, and in total, 30.30${\pm}$12.46%, 31.57 ${\pm}$15.15%, 34.25${\pm}$12.56% for the control, exp.1, and exp. 2 group respectively. There was no statistical difference among the groups. In all the groups significantly higher bone area were observed in the cortical bone compared to the marrow bone(p<0.05)