Injection molding is a process of shaping resin materials by heating them to a temperature above their melting point and then using a mold. The resin material is injected into and cooled within the mold cavity, solidifying into the desired shape. The core and cavity components that make up the mold cavity are crucial elements for the precision molding in injection molding. In the case of precision mold production, the application of 5-axis machining technology is required to ensure high machining quality for complex shapes, and among these factors, the tool angle is a critical machining condition that determines the surface roughness of the workpiece. In this study, we aim to measure the surface roughness of the machined surface of KP4A specimens during machining processes with variations in the tool angle and analyze the correlation between the tool angle and surface roughness.

This study is aimed to figure out the productivity and variability of cage-aquaculture changes. According to the analysis, the productivity of major fish species has been increasing, except mullet. Although the regional productivity has decreased in the last two years, it has been on the rise considering as a whole. Gyeongsangnam-do showed the highest level of productivity by region. Productivity by species was also higher than other regions in the cases of rock fish, mullet and sea bream followed by productivity of Chungcheongnam-do. The production of marine cage-culture in Jeollanam-do is the second largest in Korea in value/weight while its productivity is lower than that of Chungcheongnam-do. When it comes to comparison by region, Gyeongsangnam-do shows the lowest productivity variation. And Jeollanam-do shows the second-lowest variation in productivity that is only about half of that of Chungcheongnam-do province. Thus, it is found that Jeollanam-do region has an advantage in management stability while its productivity is low. On the other hand, productivity by species was also analyzed. Gyeongsangnam-do has the highest productivity by species for rock fish, mullet and sea bream whereas rock bream productivity is the highest in Jeollanam-do. Therefore, it probably needs to reflect these results when choosing regional-focused incubation fish species.

Osmotic power is to produce electric power by using the chemical potential of two flows with the difference of salinity. Water permeates through a semipermeable membrane from a low concentration feed solution to a high concentration draw solution due to osmotic pressure. In a pressure retarded osmosis (PRO) process, river water and wastewater are commonly used as low salinity feed solution, whereas seawater and brine from the SWRO plant are employed as draw solution. During the PRO process using wastewater effluent as feed solution, PRO membrane fouling is usually caused by the convective or diffusive transport of PRO which is the most critical step of PRO membrane in order to prevent membrane fouling. The main objective of this study is to assess the PRO membrane fouling reduction by pretreatment to remove organic matter using coagulation-UF membrane process. The experimental results obtained from the pretreatment test showed that the optimum ferric chloride and PAC dosage for removal of organic matter applied for the coagulation and adsorption process was 50 mg/L as FeCl3 (optimum pH 5.5). Coagulation-UF pretreatment process was higher removal efficiency of organic matter, as also resulting in the substantial improvement of water flux of PRO membrane.

Purpose: This study compares the chest compression quality, and the willingness and confidence to perform cardiopulmonary resuscitation (CPR) before and after education between the compression only CPR (COCPR) group and the standard CPR (STCPR) group using manikins. Method: This study employs a randomized controlled trial design. A total of 219 and 214 individuals were randomly assigned to the COCPR and STCPR groups, respectively. Both groups were asked to perform CPR for 2 min before and after education. The willingness and confidence to perform CPR were surveyed through a questionnaire. Results: Before education, the STCPR group had a significantly higher mean chest compression depth and accuracy than the COCPR group for the entire 2 min. After education, the STCPR group had a significantly higher mean chest compression depth for 2 min and higher compression accuracy for late 1 min than the COCPR group. However, no significant difference in the willingness and confidence to perform CPR according to the compression method was evident. Conclusion: Repeated training is required to maintain chest compression quality. CPR education improves willingness and confidence to perform CPR.

Pretreatment system of desalination process using seawater reverse osmosis(SWRO) membrane is the most critical step in order to prevent membrane fouling. One of the methods is coagulation-UF membrane process. Coagulation-UF membrane systems have been shown to be very efficient in removing turbidity and non-soluble and colloidal organics contained in the source water for SWRO pretreatment. Ferric salt coagulants are commonly applied in coagulation-UF process for pretreatment of SWRO process. But aluminum salts have not been applied in coagulation-UF pretreatment of SWRO process due to the SWRO membrane fouling by residual aluminum. This study was carried out to see the effect of residual matal salt on SWRO membrane followed by coagulation-UF pretreatment process. Experimental results showed that increased residual aluminum salts by coagulation-UF pretreatment process by using alum lead to the decreased SWRO membrane salt rejection and flux. As the salt rejection and flux of SWRO membrane decreased, the concentration of silica and residual aluminum decreased. However, when adjusting coagulation pH for coagulation-UF pretreatment process, the residual aluminum salt concentration was decreased and SWRO membrane flux was increased.

A coal dust scattered from storage and transfer facilities of coal power plant is led to a air pollution. It is difficult to reduce some scattered coal dust by used filter system such as bag filter and electric precipitator because of being scattered in the large area. The need to cut down coal dust generation has been increased as being reinforced regulation to reduce dust from coal power plant. So this is a experimental basic study which reduces coal dust generation. This study is to reduce scattering rate of the coal dust by collision and interception between fine fog droplet and coal dust particles. The reducing rate of coal dust is evaluated by droplet size of 10㎛ sprayed. It is evaluated that capture efficiency is lower as a coal dust concentration become higher. And also it is increase as droplet size is decrase and droplet density is increase. It is resulted that coal dust coefficient to optimize the fog system design is 25μg/m3/l/hr and capture efficiency of coal dust is about 80%.

버섯은 우리나라를 비롯한 전 세계적으로 널리 이용되고 있는 식품 중의 하나로 최근 다양한 생리 활성 효과 등 다양한 분야에서 활발하게 연구가 진행되고 있다. 본 연구는 여러 다양한 버섯 중에서 우리나라에서 식용으로 널리 이용되고 있는 새송이 버섯과 팽이버섯 추출물의 항산화 활성 및 세포독성 효과를 살펴보고자 하였다. 실험결과, 새송이버섯과 팽이버섯추출물의 총 페놀 함량은 각각 19.60±0.10 mg/g 과 22.28±1.10 mg/g으로 나타났으며, 플라보노이드 함량은 각각 15.21±1.31, 20.51±4.52였다. 2.5, 5.0, 7.5, 10.0 mg/mL 농도에서의 DPPH radical 소거능은 새송이버섯과 팽이버섯 각각 2.5 mg/mL의 농도에서 7.98±0.58, 8.71±0.45였고, 10 mg/mL 농도에서 각각 35.35±0.52, 39.39±0.26으로 고농도에서 높은 DPPH 라디컬 소거능을 보여주었다. 환원력은 10 mg/mL의 농도에서 각각 1.417±0.011, 1.171±0.006으로 시료의 농도가 증가할수록 흡광도 값도 증가하여, 높은 환원력을 보여주었다. 새송이버섯 추출물과 팽이버섯 추출물의 인간 정상 신장세포 HEK293으로 본 정상세포에 대한 세포독성을 측정한 결과에서는 새송이버섯, 팽이버섯 추출물 모두 80%의 생존력을 나타내어 독성이 없는 것으로 보여진다. 한편, 위암세포, 유방암세포 및 간암세포에서 암세포 성장억제율이 높게 나타나 항암 효과의 가능성을 보여주었다.

신재생 에너지의 확대를 위한 대용량 에너지 저장장치로서 레독스 흐름전지 기술의 중요성이 부각되고 있다. 레독스 흐름전지는 양극 및 음극 전해액을 셀에 순환시켜 전해액에 용해되어 있는 활물질의 산화 및 환원 반응을 유도시키는 전지로서 전지의 효율 및 수명 확보를 위해서 양쪽 전해액을 분리시켜 주며 이온전달을 일으킬 수 있는 멤브레인의 사용이 필수적이다. 그러나 기존 레독스 흐름전지에 사용되는 멤브레인은 활물질 차단 특성, 이온 전달 특성, 물리화학적 내구성 및 가격 측면에서 부족한 특성이 많으며, 이를 개선함으로서 레독스 흐름전지의 효율, 수명 향상 및 가격저감 효과를 얻을 수 있다. 본 연구에서는 이러한 레독스 흐름전지용 멤브레인의 문제점을 정리하고, 이를 개선시키기 위한 멤브레인 소재 및 구조설계 전략에 대해 논의한다. 특히 활물질 차단과 내구성 향상 혹은 가격저감을 동시에 만족시키는 복합막 기술을 소개한다.

Stable slurries of YSZ in aqueous suspension with added polymer dispersants, namely, poly-methacrylic acid ammonium salt (PMMA), poly-acrylic acid (PAA) and poly-acrylic-co-maleic acid (PAMA), were mixed with the monomolecular dispersants citric acid and oxalic acid. The dispersion properties of the suspension were investigated using PSA, viscosity, sedimentation, and FT-IR. The polymer dispersants and monomolecular dispersants were attached to the YSZ surface by the carboxylic group, as shown by the FTIR results. A stabilized aqueous suspension was obtained when the polymer dispersant and citric acid were mixed and compared to the use of citric acid alone as a dispersant agent. When the polymer dispersant and citric acid were mixed and milled through attrition milling, there was a smaller particle size compared to when the polymer dispersant alone was used as a dispersant agent. This study determined that the particle size of the mixed dispersant was affected by the properties of the monomolecular dispersant and that the stability of the suspension was affected by the polymer dispersant. However, when slurries of YSZ were mixed with oxalic acid, the particle bridging behavior was the result of the high degree of viscosity and the small sedimentation height.

This study was conducted to report the census survey results of south Korean Chikso (Korean Brindle Cattle) distribution and to diagnose the current coat color expression patterns. Two years Chikso census showed that there were 2,413 Chikso in 2013 and 2,754 in 2014 in south Korea. Number of animals between 0 to 35 months of age was 1,632 heads in 2014 which comprised 59% of total Chikso population size. The percentages of animals between 36 ~ 71 months of age and over 6 years of age were 31% and 10% of total. Out of 2,416 animals with class numbers assessed by their coat colors, 1,249 heads (52%) were in group I (with black stripes, class no. 1 ~ 3) and the others (class no. 4 ~ 7) were in group II (1,167 heads, 48%). Among the 1,551 animals that were photographed twice in 2013 and in 2014, 226 animals were assessed different coat color class numbers, and round 90% of which were within the ages less than 48 months. The number of animals switched in coat color pattern groups over a year was 56, which was 3.6% of total number of animals on survey. And around 88% of the animals switched in group category was of the animals younger than 24 months of age. Therefore, we conclude that the coat color pattern becomes rather stable at around 24 months of age in Chikso populaion in south Korea.

Control degree and property changes of dissolved organic matter (DOM) were conducted by coagulation of chemical treatment for 2 sewage treatment plants with different technical methods. As the result, SUVA value of the second treated water (supernatant of the second settling pond after biological treatment) was increased and DOC was reduced in comparison with supplied raw water. And, SUVA value and DOC were reduced by coagulation after coagulation treatment of the second treated water. Properties of dissolved organic matter for 2 sewage treatment plants's DOC were divided. As the result, there was lots of hydrophilic component with hydrophilicity in case of plant A. In case of the second treated water, Plant A showed fulvic acid with little molecular weight was reduced among the hydrophobic component with hydrophobicity, but numic acide with lots of molecular weight was increased. However, in case of plant B, both fulvic acid with little molecular weight and humic acid with lots of molecular weight were increased among the hydrophobic components with hydrophilicity. Before the operation of phosphorus facility, properties of dissolved organic matter after biodegradation with effluent water showed hydrophilic components were reduced and hydrophobic components were increased. However, after coagulation treatment of the second treated water, hydrophilic components and hydrophobic components were outstandingly decreased or increased. During the biodegradation after coagulation treatment, hydrophilic components were significantly decreased and hydrophobic components were increased.