• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.210-210
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• 2003

휘스커상의 뮬라이트의 생성온도와 속도는 출발물질로 사용되는 알루미나와 실리카의 화학적 순도, 입자크기 그리고 결정형태에 의존하며, 알루미나와 실리카의 조성비에 따라 생성되는 뮬라이트의 형태가 변한다. 각 원료에 대한 반응성을 관찰하기 위하여 출발원료인 Al(OH)$_3$, 비정질 SiO$_2$, AlF$_3$를 혼합 각각 단일조성과 2상 및 3상의 원료를 혼합 분쇄하여 분무건조한 조립분말을 5$0^{\circ}C$ 구간으로 나누어 상온에서 130$0^{\circ}C$까지 튜브 로에서 열처리하였다. Al(OH)$_3$와 AlF$_3$를 단독으로 열처리하였을 경우에는 안정한 상태로 열처리가 진행되었으나, 혼합하였을 경우에는 40$0^{\circ}C$ 이상의 온도에서 서서히 반응하였다. 각 온도구간에서 열처리한 시편은 미세구조 관찰과 상분석을 통하여 플루오르 토파즈와 휘스커상의 뮬라이트의 생성을 관찰하였으며, 생성된 휘스커 뮬라이트는 조립의 형상을 원형대로 보존하였으며, 조립의 강도를 측정하기 위하여, 초음파 분산기와, 초음파 Homgeniger를 이용하여 처리한 결과 대부분 원래의 형상을 유지하였다.

• Composites Research
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• v.18 no.2
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• pp.13-19
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• 2005

In this paper deformation of micro-mechanical parameters such as tow interval, tow thickness and change in tow amplitude are investigated by using dry fabrics (Five-harness satin weave) under shear deformation. To evaluate the observation results according to the generated in-plane forces in the material, bias extension, biaxial test results are compared with. It was found that a picture frame test with a misaligned fibre orientation angle shows large differences in deformation between tensile and compressive tow directions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1304-1307
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• 2004

실제 Cu CMP 공정이 진행되는 동안 연마입자의 응집현상을 관찰하긴 어렵다. 따라서 본 연구에서는 인위적으로 첨가한 large particle들이 공정 중에 발생하는 응집입자라 가정하고 각 공정에 따른 연마속도와 friction force를 측정하여 large particle을 첨가하지 않은 슬러리와 비교 평가해보았다. large particle을 첨가한 슬러리의 경우에 각 공정변수에 따라 연마속도와 friction force가 작아짐을 관찰하였다. 즉, 슬러리 내에 응집현상이 발생하게 된다면 large particle이 연마의 방해 인자로 나타남을 관찰 할 수 있었다.

• Journal of Veterinary Clinics
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• v.15 no.2
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• pp.378-385
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• 1998

Chloramphenicol주사에 의한 좌골신경손상을 유발한 후 Prednisolone을 이용한 약물처치군, 전침군 및 전침과 약물을 병용한 군에서 각각 회복속도를 비교하였다. 정상보행 횟수, pinching을 통한 감각신경의 통감반응,그리고 병리조직소견 등을 죠사한 결과를 요약 하면 다음과 같다. Enrofloxacin, cefazolin, cephalexin, penicillin 등의 좌골신경주위 주사게 서는 신경마비가 관찰되지 않았으나 chloramphenicol을 주사할 경우에는 좌골신경손상으로 인한 편측성 후지마비가 유발되어 knuckling 반응을 보였다. Chloramphenicol을 투여한후 좌골신경손상에 대한 각 처치에서 정상보행 횟수는 8-12주까지는 침술처치군이 약간 중가하 였으나, 처리군간 유의성은 관찰되지 않았다. 실험기간동안 chloramphenicol 에 의한 신경손 상에 대한 각 처치군별 병리조직 소견은 호전양상이 관찰되지 아니하였다.

• Journal of dental hygiene science
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• v.10 no.3
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• pp.177-183
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• 2010

This study was begun to search effect of contact angles of elastic rubber impression materials on the surface of working cast. Of elastic rubber impression materials with a Type III consistency, such as polysulfide, polyether and addition silicone, we selected one and then measured the contact angle after dripping a distilled water 3.3ml. Then, after pouring a dental anhydrite in three types of impression materials, we prepared a working cast and then examined its surface. Contact angle was measured using a full automatic contact angle measuring system (DM-700, KYOWA, Japan), and the surface of working cast was observed using a field emission scanning electron microscope (JSM-6700F, JEOL Ltd., JAPAN). The following results were obtained: 1) $Mean{\pm}SD$ (SD: standard deviation) of the initial contact angles were $91.3{\pm}20.5^{\circ}$ in the addition silicone materials, $90.0{\pm}2.2^{\circ}$ in the polyethers and $101.5{\pm}2.3^{\circ}$ in the polysulfides. These results indicate that mean values were similar but standard deviations of the three materials showed a great discrepancy. 2) As the time elapsed, addition silicone materials were found to have a contact angle decreased abruptly as compared with the remaining two types. That is, the initial contact angle was $91.3^{\circ}$ and it was abruptly decreased to $29.4^{\circ}$ after 25 seconds. 3) In the polyethers, the initial contact angle was $101.5^{\circ}$ and it was decreased to $90.7^{\circ}$ after 25 seconds. In the polysulfides, however, the initial contact angle was $90.0^{\circ}$ and it was $84.2^{\circ}$ after 25 seconds. This showed almost no changes in the initial contact angles. Moreover, its magnitude was greater than that seen in additional silicones. 4) There were significant differences in the contact angles between the three types of elastic rubber impression materials as the time elapsed (p<0.001). On an observation on the surface of working cast, addition silicone materials were found to have the most dense surface. This was followed by polysulfides and polyethers in a descending order.

• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.77-96
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• 1993

This in vitro study was undertaken to observe whether citric acid application aids the attachment and proliferation of human periodontal ligament cells to the root surfaces of periodontally diseased teeth. The roots were prepared so that the comparison could be made among the control healthy root surface, citric acid demineralized and non-demineralized root planted surfaces. Prior to the cell attachment experiment, each groups were prepared for scanning electron microscopic (SEM) examinations of root surface morphology, All specimens were fixed with phosphate buffered glutaraldehydes, postfixed with phosphate buffered osmium tetraoxide and stained with phosphate buffered tannic acid. dehydrated in ethanol, critical point dried, sputter coated with gold and examined under the SEM. In the cell attachement experiment, human cultured periodontal ligament cells at concentration to $4.5{\times}\;10^4\;cells/ml$ were seeded in each culture well which contained prepared roots and incubated for 30min 1, 2, 6, 12 and 24 hours at 37, 5% $CO_2$air incubator. Than the specimens were prepared for SEM examination using, the same methods as described above. In the cell proliferation experiment, $5{\times}\;10^4\;cells/ml$ cells were seeded incubated with the specimens for 6 hours. Then, all of the specimens were moved into fresh culture well and incubated for 24, 48, and 72 hours. The cell counting was done after trypsinization, under light microscope. The results were as follows. When viewed the surface morphology prior to the cell attachment, the non acid treated root planed surface displayed scaling striation and occasional bacteria and calculus. The citric acid treated specimens displayed little debris on the surface and funnel shaped orifices of dentinal tubules. There were no apparent differences in the morphology of cells attached to the control and experiment groups. However, in initial attachement, there was a slight more enhanced appearance in attachment in citric acid treated groups than other root surfaces. After 6 hours of incubation, most of the cells initiated the alteration of cell morphology from ovoid to spindle shapes. After 24 hours of incubation, most of the cells displayed proliferated appearance and connected with each other via numerous processes. In the cell proliferation experiments, there were statistically significant increased number of cells in citic acid treated groups than other groups.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.3
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• pp.19-29
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• 2023

This study investigated effect of water temperature change on the formation and release of conchospores of Neopyropia yezoensis. We observed that conchocelis growth and conchospores formation in oyster shell at labolatory during 7 weeks. In order to investigate the amount of conchospore formation in oyster shells, which was being cultured at 28℃, was moved to 10℃, 18℃, 28℃, and culture during 6 weeks. At 10℃, we observed an average of 127 for 1 week, 127 for 2 weeks, 95 for 3 weeks, 90 for 4 weeks, 76 for 5 weeks, and 75 for 6 weeks. At 18℃, we observed an average of 141 for 1 week, 135 for 2 weeks, 94 for 3 weeks, 153 for 4 weeks, 162 for 5 weeks, and 2 for 6 weeks. At 28℃, we observed an average of 167 for 1 week, 102 for 2 weeks, 148 for 3 weeks, 157 for 4 weeks, 270 for 5 weeks, and 138 for 6 weeks. Conchospores released from the shell grew into a young thalli in the culture for 6 weeks, and the number of ones was counted. The number of young thalli were investigated at 10℃, 0 for 1 week, 189 for 2 weeks, 200 for 3 weeks, 89 for 4 weeks, 56 for 5 weeks and 27 for 6 weeks. At 18℃, It observed 0 for 1 week, 26 for 2 weeks, 546 for 3 weeks, 16 for 4 weeks, 17 for 5 weeks and 154 for 6 weeks. It was not observed at 28℃.

• Proceedings of the Acoustical Society of Korea Conference
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• 1985.10a
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• pp.19-22
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• 1985

철(Iron)을 재질로한 ka가 큰 원통에서의 산란파를 측정 분석하였다. ka가 클 경우 산란파는 주로 Geometrical wave에 의해 구성되며, 이 Geometrical wave는 기하광학의 법칙을 따르게 된다. 본 연구에서는 각 mode의 Geometrical wave에 대하여 송.수신 위치에 따른 이론적인 펄스 도달 시간과 측정 분석된 도달시간을 비교하여 Geometrical wave를 관찰하였다.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.206-210
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• 2011

We fabricated rod-like poly(lactic acid)(PLA) specimens through applying various methods of equal-channel angular extrusion(ECAE) process and investigated the change of thermal and mechanical properties of specimens before and after each ECAE process. Combining three re-injection routes(A, BC, and C) and three pass counts(1, 2 and 4) allowed us to fabricate 7 different PLA specimens. Thermal properties of each specimen were measured by both differential scanning calorimeter and thermo-gravimetric analyzer. Shear strains of each specimen with respect to applied loads were measured by indentation hardness tester. Field emmision scanning electron microscopy was used to observe internal microstructure of cross-section of each specimen. The observed microstructures qualitatively supported the explanation of hardness test results. Among 7 specimens, PLA-P2A showed the biggest shear strain probably due to its dense microstructure.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.1
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• pp.93-100
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• 1989

The effect of each azalea(Rhodoendron mucronulatum) pollen extract on phase I enzyme(aniline hydroxylase)was studied in this experiment. Serum aminotransferases were not changed in mice injected each azalea pollen extract, respectively compared to control group. The hepatic micros mal aniline hydroxylase activities in the presence of each azalea pollen extract were not affected in vitro. After treatment with azalea pollen water extract, hepatic microsomal aniline hydroxylase activity was increased with dose-dependent manner as compared to control group. The increment of hepatic microsmal aniline hydroxylase activity was more powerful by the treatment of water extract. As mice received aniline after pollen butanol and water extract-pretreatment once a day for 5 days, the blood and liver levels of aniline were decreased significantly.