• 한국지반공학회논문집
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• 제30권7호
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• pp.5-15
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• 2014

휴 폐광산지는 산발생, 지하수 오염뿐만 아니라 침식 및 산사태 등 다양한 물리화학적 지질재해에 노출되어 있다. 임기광산 폐석적치장 광미를 대상으로 링 전단시험을 수행하여 전단속도에 따른 전단특성을 조사하고 한다. 본 연구에 있어 마찰저항을 최소화할 목적으로 링 전단상자 오링(O-ring)은 전단동안 회전이 가능하도록 설계되었다. 1차 시험은 일정한 수직응력(50kPa)과 전단속도(0.1mm/sec) 조건에서 전단시간에 따른 전단응력을 조사하였다. 2차 시험은 일정한 수직응력 조건에서 전단속도를 0.01, 0.1, 1, 10, 50, 100mm/sec로 순차적으로 증가시켜 전단속도에 따른 전단응력을 조사하였다. 3차 시험은 일정한 전단속도(0.1mm/sec)하에서 수직응력을 20, 40, 60, 80, 100, 150kPa로 증가시켜 각 경우에 대한 전단응력을 조사하였다. 시험결과에 따르면, 배수조건에 관계없이 임기광산 폐석적치장광미시료는 전단연화거동(strain softening behavior)을 보였다. 특히 전단속도가 10mm/sec보다 작은 경우 잔류전단응력은 100~300초 사이에 일정한 값에 도달하는 것으로 나타났다. 2차와 3차 시험결과에 따르면, 배수조건에 관계없이 전단응력은 전단속도와 수직응력의 함수로 나타났다. 하지만, 배수조건에 따라 링 전단상자 전단부에서 상이한 입자파쇄 특성이 관측되었다. 배수조건시 전단상자 전단면에서 하단까지 넓은 전단띠가 형성된 것에 반해, 비배수조건시 전단면에 국부 전단띠가 형성되었다. 이러한 점에 비추어 볼 때, 전단속도에 따른 입자파쇄 특성은 산사태 유동성을 높이는 중요한 인자로 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1442-1444
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• 1995

In this study, we confirmed that the crystallinity and the mechanical properties of polycrystalline Silicon(poly-Si) deposited on the poly-oxide are better than those of poly-Si on the conventional sacrificial layers that is CVD oxide layer or PSG. But the etch rate of poly-oxide is poor than that of the CVD oxide layer or PSG. Therefore, to make the best use of small stress and fast etch rate, we fabricated the double oxide layer; 10%-thick poly-oxide on 90%-thick CVD oxide or PSG. To estimate structure deformation by stress, we fabricated the test structures; cantilever. bridge and ring/beam structure and estimated by SEM. As the results, all structure is expressed the deformed structure by residual stress(tensile stress) and the deformation of the structure layer on the double oxide layer is small compared with that of the structure layer on the CVD oxide layer or PSG. And, the etch rate of the double oxide layer is enhanced compared with that of the poly-oxide.

• 대한전기학회논문지:시스템및제어부문D
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• 제51권9호
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• pp.423-430
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• 2002

The fabrication and experimentation of multi-channel electrodes which enable detecting and recording of multi-site neuronal signals have been investigated. A multi-channel electrode array was fabricated by depositing 2000${\AA}$ thick Au layer on the 1000${\AA}$ thick Ti adhesion layer on a glass wafer. The metal paths were patterned by wet etching and passivated by depositing a PECVD silicon nitride insulation layer to prevent signals from intermixing or cross-talking. After placing a thin slice of rat cerebellar granule cell in the culture ring located in central portion of the multi-channel electrode plate, a neuronal signal from an electrode which is in contact with the cerebellar granule cell has been detected. It was found that the electrode impedance ranges 200㏀∼1㏁ and the impedance is not changed by cleaning with nitric acid. Also, the impedance is inversely proportion to the exposed electrode area and the cross-talk is negligible when the electrode spacing is bigger than 600$\mu\textrm{m}$. The amplitude and frequency of the measured action potential were 38㎷ and 2㎑, which are typical values. From the experimental results, the fabricated multi-channel electrode array proved to be suitable for multi-site neuronal signal detection for the analysis of a complicated cell network.

• Journal of the Korean Wood Science and Technology
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• 제38권6호
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• pp.463-469
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• 2010

속성수의 이용가능성을 파악하기 위하여 일본산 속성수 중의 하나인 찬친모도키(Choerospondias)의 물리적 성질, 역학적 성질 그리고 흡음특성을 조사하여 주거재료로서의 적용가능성을 검토하였다. 찬친모도키재는 평균 연륜폭이 약 8 mm 정도로 생장이 빨랐으며 기건비중은 약 0.55이었다. 찬친모도키재는 다른 건축자재에 비하여 흡음성능이 열등하지 않았고 비교적 우수한 강도적 성질을 나타내어 구조재나 마감재 등에의 이용이 가능할 것으로 사료되었다.

• Korean Chemical Engineering Research
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• 제59권1호
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• pp.94-99
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• 2021

2단 Rushton turbine 날개를 장착한 접시바닥형 교반조 내의 유동 상태가 어떤 회전수에서 변화하는 현상을 찾아냈다. 층류 영역에서는 회전수를 변화시켜도 안정적인 도넛 링이 형성되어 혼합 패턴에 특이한 변동은 관찰되지 않았다. 전이영역에서의 평바닥형 교반조에서는 회전수에 변화를 주어도 두꺼운 2개의 미혼합 도넛 링에 변화가 없는 반면, 접시바닥형 교반조에서는 회전수가 450 rpm이 되면 두꺼운 2개의 미혼합 도넛 링이 아주 얇은 3개의 도넛 링으로 바뀌어 혼합이 개선되었다. 접시바닷형 교반조에서는 Re=138~178의 영역에서 링 모양의 미혼합 영역이 3곳에서 나타났고 그 크기도 컸지만, 평바닥형 교반조에서는 Re=116~176에서 링모양의 미혼합 영역은 2곳에서 나타났으며 그 크기도 작았다. 이러한 현상이 관찰되는 조건은 전이영역으로, 방해판을 부착하였을 때가 방해판이 없을 때와 비교하여 동력수가 커지기 시작하는 영역임을 알 수 있었다. 또한 교반 레이놀즈수가 300을 넘어 유동 상태에 약간의 난류가 섞이게 되면, 이 같은 흐름 양상의 단절이 해소되어 완전히 혼합되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.192-192
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• 2009

We have successfully demonstrated the inkjet printing process to fabricate $Al_2O_3$ thick films without a high temperature sintering process. A single solvent system had a coffee ring pattern after printing of $Al_2O_3$ dot, line and area. In order to fabricate the smooth surface of $Al_2O_3$ thick film, we have introduced a co-solvent system which has nano-sized $Al_2O_3$ powders in the mixture of Ethylene glycol monomethyl ester and Di propylene glycol methyl ether. This co-solvent system approached a uniform and dense deposition of $Al_2O_3$ powders on the substrate. The packing density of inkjet-printed $Al_2O_3$ films is more than 70% which is very high compared to the value obtained from the films synthesized by other conventional methods such as casting processes. The characterization of the inkjet-printed $Al_2O_3$ films has been implemented to investigate its thickness and roughness. Also the dielectric loss of the films has been measured to understand the feasibility of its application to 3D integration package substrate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.396-399
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• 2003

4H-SiC un diodes with field limiting rings(FLRs) were fabricated and characterized. The dependences of reverse breakdown voltage on the number of FLRs, the distance between p-base main junction and first FLR, and activation temperatures, were investigated. Al and B ions were implanted and activated at high temperature to form p-base region and p+ region in the n-epilayer. We have obtained up to 1782V of reverse breakdown voltage in the un diode with two FLRs on loom thick epilayer. The differential on-resistances of the fabricated diode are $5.3m{\Omega}cm^2$ at $100A/cm^2$ and $2.7m{\Omega}cm^2$ at $1kA/cm^2$, respectively. All pn diodes with FLRs have higher avalanche breakdown voltages than that of diode without an FLR. Regardless of the activation temperature, the un diode with a FLR located 5um apart from main junction has the highest mean breakdown voltage around 1600V among the diodes with one ring. On the other hand, the pn diode with two rings showed different behavior with activation temperature. It reveals that high voltage SiC pn diodes with low on-resistance can be fabricated by using the FLR edge termination.

• 대한임상검사과학회지
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• 제39권2호
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• pp.122-127
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• 2007

This study is a report about a specific patient whose primary stomach adenocarcinoma metastasized to uterine cervix adenocarcinoma. A thirty-nine year old female patient was initially diagnosed as having metastatic adenocarcinoma in the supraclavicular lymph node. Upon further examination, she was diagnosed with stomach adenocarcinoma. 8 months later, a cervix punch biopsy was performed. The stains used for examination were H&E stain, PAS stain, Alcian blue stain, Mucicarmine stain, Papanicolaou's (Pap.) stain, and as immunohistochemical stains, cytokeratin 7 and 20 were done. In the H&E stain, the tumor cells showed prominent and eccentric nuclei, thin nuclear membrane in abundant mucous cytoplasm, and cylinder shape. In the PAS stain, intracytoplasmic mucin vacuoles were stained with pink, and in Alcian blue and Mucicarmine stains, intracytoplasmic mucin vacuoles were stained with blue and red. As in the above results, she was diagnosed with undifferentiated adenocarcinoma. As found on the cytologic smear preparation of the uterine cervix stained by Papanicolaou's stains, the background was relatively clear, the number of malignant cells was relatively low, and large and eccentric nuclei in abundant cytoplasm were observed. Upon observing the tissue preparation of the uterine cervix biopsy by H&E stain, a clear background, large and eccentric nuclei, and a signet ring cell types were observed, and the number of malignant cells were fewer than in the primary uterine cervix adenocarcinoma. The vacuoles in cytoplasm were observed. The nuclear membrane and chromatin were thick and very rough, and upon observation by cytokeratin 7 and 20 of immunohistochemical stain, the tumor cells indicated a positive rate of 70% and 20%, respectively. According to these results, also she was diagnosed with metastasized uterine cervix adenocarcinoma. In summary of the results of pathologic findings on stomach biopsy and cytologic, histopathologic, and immunohistochemical finding on uterine cervix biopsy, the adenocarcinoma of her uterine cervix could assert the adenocarcinoma of signet ring cell type that was metastasized from the primary undifferentiated adenocarcinoma in stomach.

• 암석학회지
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• 제6권2호
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• pp.96-110
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• 1997

원동 칼데라의 화산작용은 화도에서 어떤 외부물과 상호작용되는 수증기마그마성 분출작용으로 시작하여 점차 물의 유입이 차단됨으로써 저플리언 분출작용으로 전환되었으며 이는 다시 회류분출로 전환되었다. 이 회류분출은 초기에는 중앙화구로부터 일어났으며 후기에는 환상 열극화구로 전환되었다. 이러한 환상 열극화구로부터 회류분출의 방출율이 급격히 커짐으로써 원동 칼데라가 형성되고 뒤이어 환상단열대를 따라 석영반암이 관입되어 환상암맥을 형성하였다. 그리고 이 칼데라 모우트에는 오랬동안 응회질 퇴적물이 채워지면서 반상유문암 용암이 초기 소생도움으로부터 분류되었으며, 환상단열대의 다른 틈을 따라 소량의 회류응회암이 분출되었다. 그리고 소생도움이 더 커지면서 세립질 화강섬록암이 관입되었으며, 마지막으로 지속적 소생작용으로 칼데라 중앙부에 각섬석 흑운모 화강암이 정치되어 완전한 소생도움을 형성하는 과정을 겪었다.

• 대한기계학회논문집A
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• 제30권1호
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• pp.76-83
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• 2006

This paper addresses the method for the shape design sensitivity analysis of the buckling load in the continuous elastic body. The sensitivity formula for critical load is analytically derived and expressed in terms of shape variation, based on the continuum formulation of the stability problem. Though the buckling problem is more efficiently solved by the structural elements such as beam and shell, the elastic solids are considered in this paper because the solid elements can be used in general for any kind of structures whether they are thick or thin. The initial stress and buckling analysis is carried out by the commercial analysis code ANSYS. The sensitivity is computed by using the mathematical package MATLAB using the results of ANSYS. Several problems including straight and curved beams under compressive load, ring under pressure load, thin-walled section and bottle shaped column are chosen to illustrate the efficiency of the presented method.