• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2006.05a
• /
• pp.251-253
• /
• 2006

본 연구에서는 Anodic Aluminum Oxide(AAO) 템플레이트 제조 시 알루미늄의 결정방위가 세공 형성에 미치는 영향을 연구하였다. 시료는 직경 20mm 두께 2mm의 세가지 단결정 시편을 사용 하였으며 이는 XRD 장비로 $2{\theta}$ 측정결과를 통해 확인 하였다. 양극 산화전 평활한 면을 얻기 위해 다이아몬드분말로 미세연마하였으며 양극산화는 세가지 시편 모두 동일한 조건에서 2단계공정까지 진행하여 반복 실험 하였다. 결과는 전계방출주사전자현미경(FE-SEM)으로 표면의 세공형태를 관찰 하였다.

• Proceedings of the Korean Society of Disaster Information Conference
• /
• 2022.10a
• /
• pp.437-438
• /
• 2022

본 논문에서는 상변환 재료를 이용하여 동절기에 발생하는 도로포장의 블랙아이스 현상을 저감시키기 위한 기초연구를 진행하였다. 콘크리트 내에서 누출을 막기 위해 마이크로 캡슐화된 상변환 재료를 이용했으며 초기 개발단계인 만큼 페이스트 단계에서 실험을 진행 하였다. 실험은 초기 수화거동에서의 수화열 발생 경향을 분석하기 위해서 미소수화열 측정 실험과 반복되는 온도변화 환경에서의 상변환재료 캡슐의 안정성을 분석하기 위해 주사전자현미경을 이용하였다. 상변환 재료의 열에너지 저장 및 방출 능력은 시멘트의 미소수화열 발생에 상당한 변화를 주었으며, 온도변화에 의한 상변환 재료 캡슐계면의 이상은 발생하지 않는 것으로 나타났다.

• Journal of Yeungnam Medical Science
• /
• v.3 no.1
• /
• pp.103-110
• /
• 1986

Cytochrome P-450(CP-450) is one of the three components of the liver microsomal enzyme system which hydroxylates fatty acids, hydrocarbons and a variety of drugs and other foreign compounds. Female Balb/c mice were immunized with purified polychlorinated bipheny(PCB)-induced CP-450 LMII. The spleen cells derived from immunized mice were fused with $SP^2$ myeloma cells using polyethylene glycol(PEG 3500). The hybrid cells were selected by hypoxanthine-aminopterine and thymidine(HAT) medium and the culture fluid were screened by enzyme-linked immunosorbent assay to CP450 LMII. The hybrid cess(${\times}10^7$) were innoculated into intraperitoneal cavity of Balb/c mice for the purpose of production of ascitic fluids. Monoclonal antibody(Mab) was purified from ascitic fluid by DEAE cellulose ion exchange chromatography and $I^{125}$-labeled Mab was also confirmed by autoradiography and SDS-polyacrylamide gel electrophoresis (MW : 55,000 and 110,000).

• Polymer(Korea)
• /
• v.30 no.5
• /
• pp.380-384
• /
• 2006

Polyhedral oligomeric silsesquioxanes (POSS) were used as starting materials for the preparation of hybrid materials with polystyrene (PS). Optically transparent hybrids were obtained in a wide range of weight ratios when phenyl groups were introduced to each corner of the silsesquioxane. In contrast, as cyclohexyl groups were introduced, the obtained hybrid materials with PS resulted in turbid films. The aromatic (${\pi}-{\pi}$) interaction was confirmed to be a quite effective tool for the synthesis of organic-Inorganic polymer hybrids with POSS. The obtained homogeneous and transparent hybrid films could be dissolved in solvents and East again without any separation. The homogeneity of polymer hybrids with POSS was supported by the result of scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC), which demonstrated a nanometer-level integration of PS and POSS.

• Korean Journal of Ichthyology
• /
• v.33 no.1
• /
• pp.15-21
• /
• 2021

The Nakdong nose loach, Koreocobitis naktongensis is an endangered freshwater fish endemic to Korea. The spawning behaviour of the K. naktongensis was observed after treating Ovaprim in laboratory aquarium from 20~27 April 2010. The behavioral patterns were categorized into three stages of pre-spawning, spawning and post-spawning behaviors. Before spawning K. naktongensis usually repeated taking a rest and swimming. On average, initial spawning activity started 11 to 12 hours later after injection with Ovaprim. During the spawning period, the number of spawning acts ranged from 1 to 18. The spawning ratio of female to male was 1 : 1. The male embraced the back of the female's dorsal fin with his lamina circularis. It looked like a complete circle at that time. After spawning, parental care was not observed. Individuals not participating in spawning have been observed to feed on some of the fertilized eggs.

• Journal of the Korea Convergence Society
• /
• v.10 no.10
• /
• pp.321-329
• /
• 2019

The purpose of this descriptive research conducted among 125 pediatric nurses was to get basic data for nursing educational program on peripheral intravenous catheterization. The collected data using Protocol of Pediatric Peripheral Intravenous Infusion of Choi et. al.(2016) and Core Basic Nursing skills & Protocol ; Intravenous Infusion of Korean Accreditation Board of Nursing Education(2017) were analyzed using SPSS 21.0. Nursing performance of pediatric nurses was the lowest in education, and the highest in side effect management. There were significant differences in subarea of nursing performance according to general characteristics. There was a positive correlation between education and nursing performance(r=.486, p<.001), and factors influencing nursing performance were education(${\beta}=.472$), working department(${\beta}=.216$) and marital status(${\beta}=.169$)(adj $R^2=0.314$, p<.001). These results can be used as basic data on nursing educational program on peripheral intravenous catheterization for pediatric nurses after repeated study by expanding the number of subjects.

• Composites Research
• /
• v.21 no.1
• /
• pp.40-45
• /
• 2008

Rubber hose assembly for automotive hydraulic brake during operation is subject to combined stresses of cyclic pressure, cyclic bending and torsion as well as thermal load. The rubber hose is composed of ethylene-propylene diene monomer(EPDM) rubber layers reinforced by polyvinyl acetate(PVA) braided fabrics. A durability tester with loading rigs for inducing the above cyclic stresses was used to investigate failure mechanisms in the rubber hose assembly. Failure examination was performed at every 100 thousands cycles of bending and torsion. Hose samples were sectioned with a diamond-wheel cutter and then polished. The polished surface was observed by optical microscope and scanning electron microscope (SEM). Some interfacial delamination with a length of about 1mm along the interface between EPDM rubber and PVA fabrics was shown at the test cycles of 400,000. The delamination induced some cracking into the outer rubber skin layer to leading the final rupture of the hose.

• Current Research on Agriculture and Life Sciences
• /
• v.6
• /
• pp.171-180
• /
• 1988

Parathion is widely used in agriculture, but it is highly toxic and now clear that parathion behaves like a cholinergic drug by inhibiting the enzyme cholinesterase. In order to know the effect of toxicity and cholinesterase activity in rats injected repeatedly with parathion, cholinesterase activity in plasma, whole brain and spinal cord, and the subacute toxicity after repetitive intraperitoneal injection of parathion 20 times every 3 days were investigated. The results obtained were summerized as follows ; $LD_{50}$ value of parathion given intraperitoneally to rats was 10.5mg/kg(95% confidence limits, 6.6-16.8mg/kg). In subacute toxicity test of parathion injected intraperitoneally, mortality of parathion-pretreated rats(B : 57%, C : 83%) were increased in comparison with the control(50%). Cholinesterase activities in plasma of parathion-pretreated rats(B : 0.47 U/ml, C : 0.36 U/ml, AA : 0.31 U/ml, B : 0.26 U/ml, CC : 0.17 U/ml) were significantly decreased in comparison with the control(0.58 U/ml). Cholinesterase activities in spinal cord of parathion-pretreated rats(B : 1.87 U/g, C : 1.29 U/g, AA : 1.27 U/g, BB : 0.71 U/g, CC : 0.25 U/g) were decreased in comparison with the control(2.48 U/g). Cholinesterase activities in whole brain of parathion-pretreated rats(B : 2.52 U/g, C : 1.32 U/g, AA : 2.48 U/g, BB : 1.08 U/g, CC : 0.51 U/g) were significantly inhibited in comparison with the control(4.67 U/g). However, there were no differences in the urea nitrogen and creatinine concentrations between parathion-pretreated rats and control.

• The Journal of Korean Academy of Prosthodontics
• /
• v.51 no.3
• /
• pp.167-174
• /
• 2013

Purpose: This study was conducted to evaluate the roughness and surface alternations of three differently blasted titanium discs treated by $Nd:YVO_4$ Laser irradiation in different conditions. Materials and methods: Thirty commercially pure titanium discs were prepared and divided into three groups. Each group was consisted of 10 samples and blasted by $ZrO_2$ (zirconium dioxide), $Al_2O_3$ (aluminum oxide), and RBM (resorbable blasted media). All the samples were degreased by ultrasonic cleaner afterward. Nine different conditions were established by changing scanning speed (100, 300, 500 mm/s) and repetition rate (5, 15, 35 kHz) of $Nd:YVO_4$ Laser (Laser Pro D-20, Laserval $Korea^{(R)}$, Seoul, South Korea). After laser irradiation, a scanning electron microscope, X-ray diffraction analysis, energy dispersive X-ray spectroscopic analysis, and surface roughness analysis were used to assess the roughness and surface alternations of the samples. Results: According to a scanning electron microscope (SEM), titanium discs treated with laser irradiation showed characteristic patterns in contrast to the control which showed irregular patterns. According to the X-ray diffraction analysis, only $Al_2O_3$ group showed its own peak. The oxidation tendency and surface roughness of titanium were similar to the control in the energy dispersive X-ray spectroscopic analysis. The surface roughness was inversely proportional to the scanning speed, whereas proportional to the repetition rate of $Nd:YVO_4$. Conclusion: The surface microstructures and roughness of the test discs were modified by the radiation of $Nd:YVO_4$ laser. Therefore, laser irradiation could be considered one of the methods to modify implant surfaces for the enhancement of osseointegration.

• Applied Microscopy
• /
• v.40 no.4
• /
• pp.193-200
• /
• 2010

This experiment was performed to evaluate the morphological responses of the duodenal epithelial cells of the mouse, inoculated with Ehrlich carcinoma cells in the inguinal area, following administration of Bacillus Calmette-Guerin (BCG). In the experimental groups, each mouse was inoculated with $1{\times}10^7$ Ehrlich carcinoma cells subcutaneously in the inguinal area. From next day after inoculations, 0.2 mL of saline or BCG (0.5 mL/25 g B.W.: $0.03{\times}10^8\sim0.32{\times}10^8$ CFU) were injected subcutaneously to the animals every other day, respectively. The day following the 7th injection of saline or BCG, each mouse was injected with a single dose of $0.7{\mu}Ci$/g of methyl-$^3H$-thymidine (25 Ci/mmol, Amersham Lab, England) through tail vein. Seventy minutes after the thymidine injection, animals were sacrificed, and duodenal tissues were taken and fixed in 10% neutral formalin. Deparaffinized sections were coated with autoradiographic emulsion EM-1 (Amersham Lab, England) in a dark room and dried and were placed in a light-tight box. The number of labeled epithelial cells in the duodenal mucosae (mean number of labeled epithelial cells per 3.5 mm length of mucosa) were observed and calculated. On the light microscopic study, duodenal mucosae had no severe morphological changes following the injection of BCG. In the tumor control and BCG treated groups, a number of small lymphocytes and eosinophile leucocytes are slightly increased as compared with those of the normal control ones. On the autoradiographic study, number of the labeled cells of normal control, tumor control and BCG-treated mice were 632.3 (${\pm}14.47$), 761.7 (${\pm}27.65$) and 505.0 (${\pm}17.09$) respectively. From the above results, BCG may suppress the DNA synthesis of the duodenal epithelial cells, but does not results severe structural defect on the duodenal mucosae. And it is suggested that BCG may greatly improve the anticancer therapy on certain kind of cancer.