• Korean Journal of Agricultural Science
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• v.6 no.2
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• pp.192-197
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• 1979

Spread factors were tried to determine the diameter of airborne droplet emitted: from the sprayer by the measurements of airborne droplet diameter emitted from the uniform size droplet producer and impression diameter on Kromekote card or Eucalypt's leaf in the different dilute concentration with Geigy Red Herbicide Dye from 0.5% to 2% by weight. The results abtained were as follows; The general form of the equation in the relationship between airborne droplet and impression diameter on Kromekote card or Eucalypt's leaf was an exponential equation as follows; $$Y=aX^b$$ which gave a linear relation on log-log graph paper. The spread factor seemed to be larger in the thin dilute concentration than in the thick dilute concentration. The spread factor was remarkably smaller on Eucalypt's leaf than on Kromekote card due to the penetration of liquid into the leaf and the stomata of the epidermis. The calculated equation of the mean depth of the droplet sprayed on Eucalypt's leaf was the same form as $Y=aX^b$, which implied that the spray liquid was distributed in surplus in accordance with the diameter of the droplet larger than the optimum size droplet to control insect and disease.

• Korean journal of food and cookery science
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• v.22 no.2 s.92
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• pp.222-228
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• 2006

The effects of olive oil addition on the quality characteristics of pound cake was investigated. Olive oil was added to the batter at a ratio of 33, 66 and 100%. The volume of pound cake prepared by adding $33{\sim}100%$ olive oil increased from 841.2 to 1083.2 mL. The volume index of pound cake prepared by adding $33{\sim}100%$ olive oil increased by $3.19{\sim}3.70$ and that of the control was 2.88. The hardness and penetration resulting from the addition of $33{\sim}100%$ olive oil decreased significantly during storage for 1 hour and 72 hours, respectively. The lightness and redness values of the cake decreased with increasing olive oil content. The taste, moistness and overall acceptability of the pound cake with 66% olive oil were the best.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.23-29
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• 2000

Objective: Zona pellucida (ZP) has been thought to be the barrier of egg to sperm penetration before and after fertilization. The phenomenon of ZP hardening has been considered as a post-fertilization event until now, and it is generally accepted that it is caused by the secretory products of cortical granules released during the cortical reaction. Hardening of ZP could occur "spontaneously" in mammalian oocytes in standard culture conditions, and that it is probably not a consequence of cortical reaction. The purpose of our study was to investigate the effect of human amniotic fluid (HAF) on nuclear maturation (NM) and fertilization ability of mouse immature oocytes. Methods: HAF was obtained from patients undergoing amniocentesis at $16{\sim}20$ weeks of gestation. HAF from five to ten patients was centrifuged and the supernatants was pooled. Cumulusenclosed mouse immature oocytes were incubated in the medium containing HAF, and examined to confirm NM and fertilization. Female ICR mice (about 3 weeks old) were stimulated with 7.5 IU PMSG. Immature oocytes were isolated at $48{\sim}52$ hrs post PMSG injection and cultured in TCM-199 supplemented with 20% HAF for 18 hrs. FBS was used as a control for the examination. Matured oocytes (MII) were fertilized with sperms collected from the epididymis of male mice (over 10 weeks old). Fertilization was in conducted T6 medium containing 15 mg/ml BSA, and confirmed at 6 hrs post-insemination. Fertilization rate was assessed in zona-intact or zona-free oocytes (denuded by trypsin). Evaluation of NM and fertilization was carried out by rapid staining method. ZP hardening was evaluated by incubating cumulus cell-free mature oocytes in 0.001% chymotrypsin at $37^{\circ}C$ for 10 min. Results: There was no significant difference between the effects of HAF (86.6%) and FBS (87.7%) supplements on NM of immature oocytes. When maturation medium was supplemented with HAF, total fertilization rates (7%) were significantly lower (p<0.01) than that of FBS (85.1%). In HAF group, fertilization rate was increased (p<0.01) in zona-free oocytes (7% versus 100%). The resistance of mouse oocyte ZP to digestion by chymotrypsin after maturation in vitro was significantly higher (p<0.01) in HAF group (86.7%) than in FBS (6.7%). To culture oocytes in FBS were very effective in preventing ZP hardening. However cultured oocytes in HAF showed high rate of ZP hardening (p<0.01). Conclusions: These results suggest that HAF can be used as a supplement for the NM of mouse immature oocytes in vitro. However, HAF induces spontaneous hardening of ZP of mouse immaure oocytes during maturation in vitro.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.4
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• pp.367-381
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• 2020

This paper presents the seal material mixing ratio of tunnel umbrella arch reinforcement method. Currently, there is no clear standard for the proper gelation time and curing time of the Seal material in Korea, and the quality control is also difficult because it cannot be verified. In response, the ratio of the mixture of the seal material was composed of four types of indoor experiments, and the amount of gelation time and bleed was checked. In addition, a non-cart penetration test confirmed the curing time and compared the ratio of each combination. Further experiments on W/C 120% identified the effect of mixing speed and time on the seal material. A total of three field experiments were conducted based on indoor experiments, and the size and strength of bulb formation were compared by checking the curing time of the specimen and main injection. Comparisons show that the lower W/C, the stronger the strength, the larger the size of the bulb, and the faster the hardening time appears. Based on the results of the gelation time and curing time, it was deemed that the mixing ratio of W/C 120% is most appropriate when applied to the actual site.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.9
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• pp.911-917
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• 2015

The objective of this work focuses on the analysis of injection rate and macroscopic spray behavior characteristics with injection pressures as well as combustion and exhaust emission characteristics with injection timing and injection pressure by using a common rail single-cylinder diesel engine. The injection rate was measured by applying the Bosch method, and macroscopic spray behavior characteristics were analyzed with a constant-volume vessel and a high-speed camera. In addition, combustion and emission characteristics were analyzed in a common-rail single-cylinder diesel engine with precise control of fuel injection timing and pressure. For injection pressures of 30MPa and 50MPa, the injection rate was higher at 50 MPa, and the spray development (penetration) was also higher in the same elapsed time. The peak in-cylinder pressure and rate of heat release showed a tendency to decline as injection timing was delayed, and the peak in-cylinder pressure and rate of heat release were slightly higher for higher injection pressures. Higher injection pressures also reduced the mean effective pressure, while the indicated mean effective pressure and torque increased as injection timing was delayed to TDC. Nitrogen oxides had a peak level at injection timings of $BTDC20^{\circ}$(30MPa) and $BTDC15^{\circ}$(50MPa); carbon monoxide emissions were reduced by delaying injection timing from $BTDC30^{\circ}$.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.130-138
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• 2020

As of 2017, the sewerage penetration rate of Seoul and metropolitan cities is more than 90%, and the number of domestic sewage treatment plants increased by 25% from 3,064 in 2010 to 4,072 in 2017. Among them, sewage treatment plant operated by SBR system is 585, which is 17% higher than 2010. In order to improve the water quality of the water source and improve the operation of the small sewage facilities, the improvement of the process was studied by applying the modelling to 49 facilities of the sewage treatment plant in Andong Imha dam area with more than 500㎥/day 3 places and 46 places less than 500㎥/day. As an improvement plan for modelling, candidate data were derived by reviewing operation data for 5 years. 49 facilities are operated by 12 types of operating processes. Among them, 1 place mort than 500㎥/day with SBR method and 9 facilities with less than 500㎥/day were selected by dividing 46 sites into 3 types. As a result of applying modelling to more than 500㎥/day, it was possible to improve the quality of discharged water through SRT control and it was found that applying model to sites of small scale treatment plants can improve the removal efficiency of TP by up to 14.4%. As a result, the data of this study could be used to improve and improve the operation of sewage treatment plants and RCSTP(Rural Community Sewage Tratment Plant).

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.473-484
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• 1994

To investigate the effect of resin cement, which had been known to increase the adhesive capacity of the cast gold inlay, on the gingival marginal fit and whether the tin-planting of the beveled area affects the marginal fit, Class II cast gold inlays were made on the 25 sound molars. Control group(ZPC goup) was cemented with the ZPC by conventional method. Experimental groups were cemented with the resin cement(Super-hond & $Panavia_{EX}$) and subdivided further by the existence or nonexistence of the tin-plating of the beveled area(ST & PT groups: with plating, SNT & PNT groups: without plating). So, each group was consisted of 5 teeth and the gingival margin of each specimen was mesiodistally sectioned by 3 times and the marginal and internal gap were evaluated by the Stereo Microscope (${\times}180$) and the Scanning Electron Micrascope(${\times}5,000$) was used for examining the adhesive relationship of the resin cement to the cavity wall and to the cast gold surface. The results were as follows : 1. Marginal gap was less than internal gap in all groups. 2. ZPC and SNT(bevel without tin-plating) groups showed the least gap and gap in PNT(bevel without tin-plating) group, ST(bevel with tin-plating) group, PT(bevel with tin-plating) group showed the greater value in order in evaluation of the both internal gap and marginal gap. 3. With the exception of the relationships between ZPC and SNT groups, ST and PNT groups, relationships between any other groups showed the statistical significance in the internal gap(p<0.05). 4. In the marginal gap, all relationships between groups showed the statistical significance (p<0.05) except the relationships between ZPC and SNT groups, ST and PNT groups, ZPC and PNT groups. 5. ZPC group showed more soluble phenamena than the resin groups(ST, SNT, PT, PNT). 6. Resin cement showed the void spaces in spite of good penetration into the micro-irregularities on both the tooth surface and the cast surface. The void was shown more in PT and PNT groups than in the ST and SNT groups. 7. After the treatment of heat and desiccation for SEM specimen, resin cements were detached more easily from the tooth surface than from the cast surface.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.303-310
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• 2018

One of most shocking headlines is a serious chain collision accident (CCA). The development of CCA has a temporal and spatial locality, and the information of the CCA is time-critical. Due to these characteristics of CCA, traffic accident information should be rapidly propagated to drivers in order to reduce chain collisions, right after the first accident occurs. Inter-vehicle communication (IVC) based on ad-hoc communication is one of promising alternatives for locally urgent information propagation. Despite this potential of IVC, research for the effects of IVC on the reduction of CCA has not been reported so far. Therefore, this study develops the parallel platform of microscopic vehicle and IVC communication simulators and then analyses the effects of IVC on the reduction of the second collision related to a series of vehicles. To demonstrate the potential of the IVC-based propagation of urgent traffic accident information for the reduction of CCA, the reduction of approaching-vehicle speed, the propagation speed of accident information, and then the reduction of CCA were analysed, respectively, according to scenarios of combination of market rates and traffic volumes. The analysis results showed that CCA can be effectively reduced to 40~60% and 80~82% at the penetration rates of 10% and 50%, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.387-395
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• 2013

Recently, several circumferential cracks were found in the control rod drive mechanism (CRDM) nozzles of U.S. nuclear power plants. According to the accident analyses, coolant leaks were caused by primary water stress corrosion cracking (PWSCC). The tensile residual stresses caused by welding, corrosion sensitive materials, and boric acid solution cause PWSCC. Therefore, an exact estimation of the residual stress is important for reliable operation. In this study, finite element simulations were conducted to investigate the effects of the tube geometry (thickness and radius) on the residual stresses in a J-groove weld for different CRDM tube locations. Two different tube locations were considered (center-hole and steepest side hill tube), and the tube radius and thickness variables ($r_o/t$=2, 3, 4) included two different reference values ($r_o$=51.6, t=16.9mm).

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.6
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• pp.504-509
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• 2016

Defects in dissimilar metal welds are reported to be on the increase during the operating lifespan and aging of nuclear power plants. In Korea, reported cases of defects due to dissimilar metal welds include the drain nozzle of a steam generator and RCS hot tube sampling nozzles. Therefore, there is an urgent need to develop a reliable automated nondestructive inspection technique and a system for the inspection of dissimilar metal welds of small diameter nozzles in a high radiation area of a nuclear power plant. In this study, to ensure effective defect inspection of small diameter nozzles (RCS high-temperature tube sampling nozzle) of a nuclear power plant, three different methods were developed. These include: (1) optimum inspection probe design by beam simulation, (2) multi-directions UT optimum inspection technique for the inspection of small diameters of different welded parts, and (3) remote control automatic inspection system. The developed technique and systems have been verified to be suitable for use in the inspection of defects in smaller diameter nozzles in nuclear power plants.