소규모사업장 용접근로자들의 소음·용접흄·망간 노출에 관한 연구

김동구,문덕환,이채관,박명희,함성애,손병철,김대환,이창희,김휘동,이채언 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.5

Objective : This study was conducted for the purpose of investigating the level exposure of welders to noise, welding fume and Manganese(Mn) related to this process. Methods and Material : All subjects in this study were welders engaged in CO2 arc and coated arc welding process especially in small-scale enterprises classified by type of manufacture of ship building, repairing and of other fabricated metal products, which is located in Gimhae and Milyang of Kyeongsang province in south Korea. Air sampling of welding fume was measured, shipped and analyzed on the basis of national institute for occupational safety and health(NIOSH) method in U.S. and work environment measurement method established in south Korea. To measure Noise in the work environment, Noise dosimeter was used on the basis of work environment measurement method established in south Korea. Result : This study was performed during a period from January, 2000 to December, 2001 and Results were as follows: 1. Noise level measured in this work environment was higher than national criteria for permissible exposure limit on health examinations related to hearing loss. 2. The concentration of welding fume and Mn in manufacture of ship building and repairing was higher than those in manufacture of other fabricated metal products. 3. In conditions of existing in ventilation system installed and operated, the concentration of welding fume and Mn was slightly lower than those of not existing. 4. In conditions of existing in sufficient air supply from out door into the work place relied on natural exhaust system, the concentration of welding fume and Mn was slightly lower than those of in not sufficient. 5. In all subjects, a rate of wearing ear plug and respiratory mask for dust and fume was lower than that of not wearing. Conclusion : According to above results, this study suggests that more positive work environment managements such as the use of portable local ventilation system, the supply of highly qualified personal protective equipment, and consecutive education and training related to health protection should be need to acquire suitable health protection program for welders engaged in small-scale enterprises in Korea.

곡관덕트에서 난류정상유동의 벽면전단응력분포와 입구길이에 관한 실험적 연구

손현철,이홍구,김대욱,김명호,박길문 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.1

In this paper, an experimental investigation of characteristics of developing turbulent steady flows in a square-sectional 180°curved duct is presented. The experimental study using air in the square-sectional 180°curved duct is carried out to measure entrance length and wall shear stress distributions by using Laser Dopper Velocimeter(LDV) system with data acquisition and processing the system of FIND6260 software at 7 sections from the inlet(ø=0°) to the outlet(ø=180°)in 30°intervals of the curved duct. The results obtained from experimental studies are summarized as follows : (1) The critical Dean number of turbulent steady flow is about 560. (2) The value of the wall shear stress becomes minimum in the inner wall and gradually increases toward the outer wall where it becomes maximum. (3) The entrance length of the turbulent steady flow is shorter than that of the traditional steady flow, reaching the vicinity of bend angle 90°

Fabrication and characterization of planar-type SOFC unit cells using the tape-casting/lamination/co-firing method

Myung, Jae-ha,Ko, Hyun Jun,Park, Hae-Gu,Hwan, Moon,Hyun, Sang-Hoon Elsevier 2012 International journal of hydrogen energy Vol.37 No.1

<P><B>Abstract</B></P><P>In this study, solid oxide fuel cells (SOFCs) consisting of a NiO-YSZ anode, a NiO/YSZ-YSZ functional layer, YSZ electrolyte and a (La<SUB>0.8</SUB>Sr<SUB>0.2</SUB>)MnO<SUB>3</SUB> + yttria-stabilized zirconia (LSM-YSZ) cathode were fabricated by tape-casting, lamination, and a co-firing process. NiO/YSZ-YSZ nano-composite powder was synthesized for the anode functional layer via the Pechini process in order to improve cell performance. After optimization of the slurries for the anode functional anode, electrolyte and cathode, all components were casted so as to fabricate the monolithic laminate. The co-firing temperature was optimized to minimize second phase formation between the (La<SUB>0.8</SUB>Sr<SUB>0.2</SUB>)MnO<SUB>3</SUB> (LSM) and yttria-stabilized zirconia (YSZ) and to increase the sinterability of the YSZ electrolyte. The YSZ electrolyte was fully sintered with the addition of 0.5 wt% CuO, and the second phases of La<SUB>2</SUB>Zr<SUB>2</SUB>O<SUB>7</SUB> and SrZrO<SUB>3</SUB> did not form at 1350 °C. Ni-YSZ anode-supported unit cells were fabricated by co-firing at 1250–1400 °C. The unit cells co-fired at 1250 °C, 1300 °C, 1325 °C, 1350 °C and 1400 °C had maximum power densities of 0.18, 0.18, 0.30, 0.46 and 0.036 W/cm<SUP>2</SUP>, respectively, in humidified hydrogen (∼3% H<SUB>2</SUB>O) and air at 800 °C.</P> <P><B>Highlights</B></P><P>► We fabricated anode-supported SOFC unit cells via tape-casting/lamination/co-firing method. ► Co-firing temperature was optimized to reduce 2nd phases formation in cathode. ► NiO/YSZ-YSZ nano-composite powders increased power density of co-fired unit cells. ► The unit cell co-fired at 1350 °C showed 0.46 W/cm<SUP>2</SUP> and good stability over 100 hr.</P>

Fine Structure of the Mouthparts in the Ambrosia Beetle Platypus koryoensis(Coleoptera: Curculionidae: Platypodinae)

Moon, Myung-Jin,Park, Jong-Gu,Kim, Kyung-Hee The Korean Society for Integrative Biology 2008 Animal cells and systems Vol.12 No.2

Recently, Platypus koryoensis has been reported as a major pest of oak trees in Korea which can introduce the pathogenic fungus(Raffaelea sp.) by making galleries into the heartwood of the tree. As the beetle has developed its effective drilling mouthpart enough to make tunnels, we have analyzed the fine structural aspects of the mouthpart using the field emission scanning electron microscopy(FESEM) to reveal its mechano-dynamic characteristics. The mouthparts of this ambrosia beetle which consist of a labrum, a pair of mandibles, a pair of maxillae and the labium exhibit typical morphology of mycophagous coleopteran beetles and have those characteristics of chewing mouthparts that can excavate galleries in the hardwood. Both of maxillary and labial palpi have the functions of direct the food to the mouth and hold it while the mandibles chew the food. The distal ends of these palpi are flattened and have shovel-like setae. Females have larger maxillary palpi and a larger gular region than males in general.

Fine Structural Analysis on the Dry Adhesion System of the Jumping Spider Plexippus setipes (Araneae: Salticidae)

Moon, Myung-Jin,Park, Jong-Gu The Korean Society for Integrative Biology 2009 Animal cells and systems Vol.13 No.2

The cuticle of spider's exoskeleton is a hydrophobic and non-adhesive material, but the jumping spiders have the distinctive attachment apparatus for adhesion on smooth dry surface without sticky fluids. We have examined the whole tarsal appendages of the jumping spider, Plexippus setipes with using scanning electron microscope to reveal the fine structural characteristics of the dry adhesion system. All eight legs have the scopulae with a pair of claws on the tip of feet. Each scopula is composed of two groups of setae that are capable of dry adhesion on smooth surface, and the hook structure of the claw is advanced to move on the rough surface. The setae toward the bottom of the tarsal segment are densely covered by numerous setules on the underside which broadened from middle to distal portion. It has been revealed by this research that the contact area of the setule is always a triangular shape, and these cuticular surfaces are connected by the elongated stalks from the underlying setae. It is likely that the nano-scale structures including a triangular depression and a longitudinal groove on each setule could functionate when the spider detach its feet from the substrate.

Microstructure of the biological attachment devices in the ladybug Harmonia axyridis (Coleoptera: Coccinellidae)

Moon, Myung-Jin,Kim, Hyo-Jeong,Kim, Hoon,Park, Jong-Gu The Korean Society for Integrative Biology 2012 Animal cells and systems Vol.16 No.6

Biological attachment device is optimized in insect legs for attachment onto the variety of natural substrate. We have studied the microstructural characteristics of the tarsal appendages in the ladybug Harmonia axyridis using scanning electron microscopy to reveal the attachment system of their legs. The attachment devices are composed of claws and adhesive pads. The claws are connected with pretarsal segment, and their apical diverged hooks are developed to hold rough substrates. In contrast, the adhesive pads have an adhesive function onto smooth surface. The pads are interspersed at the ventral part of each tarsomere, and are composed of two kinds of hairy setae. The discoid tip seta (DtS) has a spoon-shaped endplate usually with a rounded concave structure, whereas the pointed tip seta (PtS) has a pointed tip, usually with a hooked endplate. While the PtS is broadly localized concentrically on the marginal area of both the proximal and distal pads, the DtS can be seen at the central areas of each adhesive pad except for the hind legs. Our findings demonstrate the presence of the direction-dependence pattern of the fibrillar system as well as a functional modification of the tenent setae to achieve proper contact with almost any kind of substrates.

Effect of Lactic Acid Bacteria on the Regulation of Blood Glucose Level in Streptozotocin-induced Diabetic Rats

Moon-Hwan Yeo,Jae-Gu Seo,Myung-Jun Chung,Hyun-Gi Lee 한국동물번식학회 2010 Reproductive & developmental biology Vol.34 No.4

External microstructure of the ambrosia beetle<i>Platypus koryoensis</i>(Coleoptera: Curculionidae: Platypodinae)

MOON, Myung-Jin,PARK, Jong-Gu,OH, Eunsung,KIM, Kyung-Hee Wiley (Blackwell Publishing) 2008 Entomological Research Vol.38 No.3

Fine Structure of the Antennal Sensory Organs in the Bark Beetle Ips acuminatus (Coleoptera: Curculionidae: Scolytinae)

Myung-Jin Moon,Hoon Kim,Hyo-Jeong Kim,Yong-Ki Park,Jong-Gu Park,Won-Il Choi 한국응용곤충학회 2013 한국응용곤충학회 학술대회논문집 Vol.2013 No.10

Ips acuminatus is a minute bark beetle found in forest and can cause economic damage to pine and spruce trees. This beetle has well developed sensory system respond to both of visual and chemical stimuli. Both sexes have a pair of faceted compound eyes and another pair of knobbed antennae, work together to collect vital information. The antennae look similar in both sexes and consist of scape, pedicel, and segmented flagellum. The pedicel is the first segment by which the antenna is attached to the head and the scape is set in a membranous socket and surrounded by the antennal sclerite on which a single articulation occurs. The beetle’s antennae enlarge abruptly at the last segment of a flagellum giving the antenna a knobbed appearance. There are a number of sensory receptors, including olfactory and mechanical receptors. Here, the fine structural characteristics of the antennal sensory organs in male and female bark beetle Ips acuminatus (Coleoptera: Curculionidae: Scolytinae) were analysed with field emission scanning electron microscopy (FESEM).

대학생의 중도탈락에 영향을 미치는 대학기관 변인 분석

구성우(Gu Sung woo),문명현(Moon Myung hyun),김병주(Kim Byoung joo) 한국교육재정경제학회 2016 敎育財政 經濟硏究 Vol.25 No.4

본 연구는 대학기관 차원에서 대학생의 중도탈락에 영향을 미치는 대학기관 변인을 분석하고 자 하였다. 분석에 활용한 자료는 ‘에듀데이터 서비스 시스템(EDSS: Edu Data Service System)’을 활용하여 추출하였다. 이 자료 중 2012년~2014년 자료가 모두 공개되어 있는 4년제 대학교 150개교를 대상으로 대학재정, 교육여건, 교육 및 연구 변인을 선정하여 분석을 실시하였다. 연구방법은 AMOS 프로그램을 활용하여 다변량잠재성장모형을 활용하였다. 연구모형에 있어서 각 변인별 변화모형을 분석한 결과 모든 변인에서 무변화모형보다 선형모형의 적합도가 더 우수한 것으로 나타났다. 연구결과, 전체 대학의 경우는 학생 1인당 교육비 및 기숙사 수용률, 전임교원 1인당 논문 수와 전임교원 1인당 교외 연구비 높을수록 중도탈락을 낮추는 것으로 나타났다. 소재지를 구분했을 경우, 수도권 대학은 학생 1인당 교육비, 학생 1인당 등록금, 전임교원 1인당 논문수와 전임교원 1인당 교외 연구비 높을수록 중도탈락을 낮추는 것으로 나타났다. 하지만 전임교원 1인당 교외 연구비가 높을수록 중도탈락률의 시간적 변화에 있어서는 중도탈락을 높이는 것으로 나타났다. 마지막으로 비수도권의 경우는 학생 1인당 교육비, 기숙사 수용률, 전임교원 1인당 논문 수가 높을수록 중도탈락을 낮추는 것으로 나타났다. 결국, 대학생의 중도탈락을 낮추기 위한 대학의 노력에 있어서는 대학별로 특성에 맞는 재정 투자 및 여건 개선 등이 이루어져야 할 것이다. The purpose of this study is to analyze the institutional variables which affect dropout of college students in universities. In order to achieve the purpose of this study, Multi-variate latent growth model in the basis of AMOS program was used. It was appeared that the suitability of linear model was more outstanding than that of no-change model after analysing change model of each factor. The data utilized in this analysis was collected from EDSS, Edu Data Service System. This analysis was conducted on one hundred and fifty universities with reference to their data from 2012 to 2014 with university fiance, educational condition, and education/research factors selected. The result of this study indicated that in case of all the universities the more and higher educational expenses and receptive capacity of dormitory per student, and the number of theses and research expenses used in extramural activity per faculty in full service were, the lower dropout rate was. When locate of universities was separated, in case of the universities in capital region, it was shown that the more and higher educational expenses and registration fee per student, and the number of theses and research expenses used in extramural activity per faculty in full service were, the lower dropout rate was. However, it is also appeared that the higher research expenses used in extramural activity per faculty in full service were, the higher dropout rate was in process of time. Lastly, in case of universities located in non-capital region, the more and higher educational expenses and receptive capacity of dormitory per student, and the number of theses per faculty in full service, the lower dropout rate is. In conclusion it is required for each university to focus on financial investment and condition improvement suitable for its own characteristic so as to lower dropout rate of college student.