• 비파괴검사학회지
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• 제29권3호
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• pp.214-218
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• 2009

The occlusal force of the tooth leads to loss of tooth tissue owing to attrition and abrasion, and may cause abfraction and pathological change of the dentin. Thus, we developed finite element models, examined them by applying ordinary occlusal force, and analyzed the stress distribution. Specimens used were mandibular first premolars from 15 Korean males and 13 females and were made into finite element models from medical images that were obtained using a Micro-CT. We have found that the irregular feature of the tooth is not only useful to masticating and pronouncing as well known, but it is also suitable for protecting inner tissue by dispersing stress and delivering proper pressure to periodontal tissue to continue a physiological action. Also, image analysis could let us know the factor that is the cause of a disorder due to stress concentration in the cervical line. These results are expected to support the field of dental treatment planning, operating procedure and clinical trial, and the advance of technical expertise to develop implants and dentures.

• 반도체디스플레이기술학회지
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• 제5권3호
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• pp.5-10
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• 2006

This paper investigates cutting qualities after laser dicing and predicts the problems that can be generated by laser dicing. And through 3 point bending test, die strength is measured and the die strength after laser dicing is compared with the die strength after mechanical sawing. Laser dicing is chiefly considered as an alternative to overcome the defects of mechanical sawing such as chipping on the surface and crack on the back side. Laser micromachining is based on the thermal ablation and evaporation mechanism. As a result of laser dicing experiments, debris on the surface of wafer is observed. To eliminate the debris and protect the surface, an experiment is done using a water soluble coating material and ultrasonic. The consequence is that most of debris is removed. But there are some residues around the cutting line. Unlike mechanical sawing, chipping on the surface and crack on the back side is not observed. The cross section of cutting line by laser dicing is rough as compared with that by mechanical sawing. But micro crack can not be seen. Micro crack reduces die strength. To measure this, 3 point bending test is done. The die strength after laser dicing decreases to a half of the die strength after mechanical sawing. This means that die cracking during package assembly can occur.

• Transactions on Electrical and Electronic Materials
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• 제7권4호
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• pp.157-162
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• 2006

Chemical-mechanical polishing (CMP), one of the dominant technology for ULSI planarization, is used to flatten the micro electro-mechanical systems (MEMS) structures. The objective of this paper is to achieve good planarization of the deposited film and to improve deposition efficiency of subsequent layer structures by using surface-micromachining process in MEMS technology. Planarization characteristic of poly-Si film deposited on thin oxide layer with MEMS structures is evaluated with different slurries. Patterns used for this research have shapes of square, density, line, hole, pillar, and micro engine part. Advantages of CMP process for MEMS structures are observed respectively by using the test patterns with structures larger than 1 urn line width. Preliminary tests for material selectivity of poly-Si and oxide are conducted with two types of silica slurries: $ILD1300^{TM}\;and\;Nalco2371^{TM}$. And then, the experiments were conducted based on the pretest. A selectivity and pH adjustment of slurry affected largely step heights of MEMS structures. These results would be anticipated as an important bridge stone to manufacture MEMS CMP slurry.

• 한국전자통신학회논문지
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• 제3권3호
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• pp.153-157
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• 2008

MCS(Micro-coplanar strip) 선은 전부터 분석되어 왔었다. 등각 지도로 나타낸 방법은 이 MCD 선의 준정적인 효과적인 유전율 그리고 독특한 임피던스를 산출하기 위하여 이용되곤 했다. 현재 이용되는 모든 성과들은 상업적인 S/W, IE3D를 사용하여 얻어진 결과와 비교할 때 유리한 계약에 있기 위해서이다. 그리고 이 부분에서, 적합한 임피던스 저역 원반꼴 안테나 여과기는 주파수 응답 개량을 위한 MCS 선으로 디자인되고 날조되었다. LPF는 구조는 또한 디자인되고 정지하여 있는 예리한 묶음성 특성이 유지하기 위하여 끈을 실행할 수 있도록 하였다. 가장 끝과 측량 결과에서의 결과는 실행한 LPF로 확인할 수 있다.

• 한국환경과학회지
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• 제31권5호
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• pp.447-456
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• 2022

This study was conducted to propose a way to increase the accuracy and precision of 𝛽-ray measurement equipment. Statistical processing results of equivalent evaluation data from 2016 to 2021 confirmed that the concentration of micro dust measured by 𝛽-ray measurement equipment was higher than that of micro dust sampler. According to quarterly data, it was confirmed that the data from the third quarter (July to September) showed a different trend from other periods, which is assumed to be due to weather conditions. This study indicates that automatic micro-dust measurement equipment evaluation at air pollution measuring stations during the third quarter should be excluded. The evaluation cycle should be changed from once every two years to quarterly. In addition, when the criterion for determining equivalence evaluation falls within the range of the slope and intercept values of the existing trend line, it is necessary to evaluate the R² value together and reduce the slope from 0.9-1.1 to 0.9-1.0.

• Asian Pacific Journal of Cancer Prevention
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• 제14권6호
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• pp.3751-3755
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• 2013

Backgroud and Aims: MicroRNA-206 has proven to be down-regulated in many human malignancies in correlation with tumour progression. Our study aimed to characterize miR-206 contributions to initiation and malignant progression of human osteosarcoma. Methods: MiR-206 expression was detected in human osteosarcoma cell 1ine MG63, human normal osteoblastic cell line hFOB 1.19, and paired osteosarcoma and normal adjacent tissues from 65 patients using quantitative RT-PCR. Relationships of miR-206 levels to clinicopathological characteristics were also investigated. Moreover, miR-206 mimics and negative control siRNA were transfected into MG63 cells to observe effects on cell viability, apoptosis, invasion and migration. Results: We found that miR-206 was down-regulated in the osteosarcoma cell line MG63 and primary tumor samples, and decreased miR-206 expression was significantly associated with advanced clinical stage, T classification, metastasis and poor histological differentiation. Additionally, transfection of miR-206 mimics could reduce MG-63 cell viability, promote cell apoptosis, and inhibit cell invasion and migration. Conclusions: These findings indicate that miR-206 may have a key role in osteosarcoma pathogenesis and development. It could serve as a useful biomarker for prediction of osteosarcoma progression, and provide a potential target for gene therapy.

• 한국정밀공학회지
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• 제31권6호
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• pp.483-489
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• 2014

In this study, experiments were conducted for micro pattern printing to combine solution atomization process and stencil printing based on electrospray deposition. The stencil mask fabricated by etching the photosensitive glass placed below 0.3 mm distance to substrate has 100 um line width. The process parameters of electrospray deposition system for the atomization of the solution are applied voltage and supply flow rate of the solution. Meniscus angle of cone-jet was optimized by varying the supply flow rate from 0.3 ml/hr to 0.7 ml/hr. Voltage condition was verified having symmetric cone-jet angle and no pulsation at 8.5 kV applied voltage. In addition, a number of micro patterns are printed using a single 1 step process by solution atomization process. Variable line width of approximate 100 um was confirmed by changing conditions of solution atomization regardless of the pattern size of stencil mask.

• 지구물리와물리탐사
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• 제19권2호
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• pp.97-104
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• 2016

우리나라 남동부에 위치한 경주와 그 주변지역에서는 과거부터 최근까지 크고 작은 지진이 반복적으로 발생하고 있다. 계기지진자료를 검토하여 경주 주변 약 $20km{\times}30km$ 지역 내에서 지진이 많이 발생하고 있음을 확인하였다. 본 연구에서는 이 지역에서 2010년 1월부터 2014년 12월 사이에 발생했지만, 그 규모가 너무 작아 미처 보고되지 않은 300개 이상의 미소지진을 식별하고 그 발생위치를 결정하였다. 연구지역 지하의 속도구조와 진원요소 결정에 사용하는 속도모델의 차이로 인한 오차를 줄이기 위하여 JHD 방법을 사용하였다. 연구지역에서는 활성으로 의심되는 제4기 단층들이 여러 장소에서 보고되고 있으므로, 이 단층들과 미소지진발생과의 관련 가능성을 조사하였다. 본 연구에서 새로이 발생사실이 보고되는 미소 지진들은 연일구조선의 남측분절, 석읍단층 그리고 와읍분지 경계단층과 관련이 있는 것으로 나타난다.

• 대한핵의학회지
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• 제39권1호
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• pp.49-56
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• 2005

목적: 새로운 PET 추적자와 약물 개발, 유전자 및 줄기세포치료 연구 등에 소동물 전용 PET이 유용하게 쓰이고 있으며, 국내에도 최근에 microPET R4 소동물 전용 PET이 설치되어 각종 기초연구에 활발히 이용될 전망이다. 이 연구에서는 국내에 최초로 설치된 microPET R4 스캐너의 물리적 특성(공간분해능, 균일도, 민감도, 산란분획, NECR)을 측정하였다. 대상 및 방법: 내경 0.5 mm의 가는 모세관을 F-18으로 채워 만든 선선원을 이용하여 공간분해능 및 민감도를 측정하였다. 반경방향(radial) 및 접선방향(tangential) 분해능을 측정하기 위하여 60 mm의 선선원(65 ${\mu}Ci$)을 축방향과 나란하게 놓은 후 횡단면상 중앙에서부터 1 mm 간격으로 중심에서 4 cm 벗어난 지점까지 옮겨가며 각 2분간 PET 영상을 얻었다. 축방향(axial) 공간분해능 측정을 위하여서는 선선원을 축방향과 수직으로 놓고 동일한 실험을 반복하였다. PET 영상은 FBP 방법과 OSEM 방법으로 각각 재구성하였으며 가우시안 함수로 곡선정합하여 반치폭값을 구하였다. 축방향 위치에 따른 민감도 측정을 위하여 축방향 시야 길이와 동일한(78 mm) 선선원(16.5 ${\mu}Ci$)을 횡단면 중심에 축방향과 나란하게 위치시키고 불응시간이 1%이하가 됨을 확인한 후 축방향 중심에서 바깥방향으로 39 mm까지 (0.5 mm간격) 이동시키면서 각 4분간 PET 영상을 얻었다. 총동시계수에서 지연계수를 빼고 방사선 붕괴를 보정한 후 민감도를 계산하였다. 지름 60 mm, 길이 150 mm의 원통형 팬텀을 제작하여 NECR과 산란분획을 7반감기 동안 각 20분씩 얻은 데이터로부터 계산하였다. 결과: FBP로 재구성한 영상의 공간분해능은 횡단면 중심에서 각각 1.86 mm(반경 방향), 1.95 mm(접선방향), 1.95 mm(축방향)이었으며 중심에서 2 cm 벗어난 지점에서 각각 2.54 mm, 2.8 mm, 1.61 mm이었다. OSEM 영상의 공간분해능은 중심에서 각각 1.44 mm, 1.36 mm, 1.61 mm이었으며 중심에서 2 cm 벗어난 지점에서 각각 1.86 mm, 2.29 mm, 2.88 mm이었다. 민감도는 축방향 중심에서 2.36%, 축방향 시야길이의 1/4인 18.5 mm 지점에서 2.09%이었다. 산란분획은 20%이었으며, 최대 NECR은 242 kBq/mL에서 66.4 kcps이었다. 생쥐와 백서, 그리고 고양이의 뇌영상을 획득하여 영상의 품질을 확인하였다. 결론: 국내에 설치된 microPET R4의 공간분해능 및 민감도는 기존에 알려진 값들과 거의 유사하였으며, 소동물 PET 영상을 위하여 적합한 것으로 보인다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.485-488
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• 2000

This paper proposes to design the residential power line communication device using Softwire Protocol, which targets the device with 8bit micro-controller and small-size memory based on low-rate power line communication network or wireless communication network. As a case study, the SCP message specification of air-conditioner that has capability of control and monitoring its status is designed using Softwire Protocol. And, it is described how the device operates sequentially.