• 한국멀티미디어학회논문지
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• 제22권12호
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• pp.1376-1384
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• 2019

The cosmetic and behavioral aspects of aging have become increasingly evident over the years. Physical aging in people can easily be observed on their face, posture, voice, and gait. In contrast, bone aging only becomes apparent once significant bone degeneration manifests through degenerative bone diseases. Therefore, a more accurate and timely assessment of bone aging is needed so that the determinants and its mechanisms can be more effectively identified and ultimately optimized. This study proposed a deep learning approach to assess the bone age of an adult using whole-body bone scintigraphy. The proposed approach uses multiple inputs deep neural network architectures using a loss function, called mean-variance loss. The data set was collected from Chonnam National University Hwasun Hospital. The experiment results show the effectiveness of the proposed method with a mean absolute error of 3.40 years.

• JSTS:Journal of Semiconductor Technology and Science
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• 제13권5호
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• pp.516-521
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• 2013

This paper investigates the two dominant but intertwined current blocking mechanisms of Switching and Kirk Effect in pure ternary InAlAs/InGaAs/InAlAs Double Heterojunction Bipolar Transistors (DHBTs). Molecular Beam Epitaxy (MBE) grown, lattice-matched samples have been investigated giving substantial experimental results and theoretical reasoning to explain the interplay between these two effects as the current density is increased up to and beyond the theoretical Kirk Effect limit for devices of emitter areas varying from $20{\times}20{\mu}m^2$ to $1{\times}5{\mu}m^2$. Pure ternary InAlAs/InGaAs/InAlAs DHBTs are ideally suited for such investigations because, unless corrective measures are taken, these devices suffer from appreciable current blocking effect due to their large conduction band discontinuity of 0.5 eV and thus facilitating the observation of the two different physical phenomena. This enhanced understanding of the interplay between the Kirk and Switching effect makes the DHBT device design and optimization process more effective and efficient.

• 센서학회지
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• 제13권2호
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• pp.90-95
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• 2004

Protein and gene detection have been growing importance in medical diagnostics. Field effect transistor (FET) - type biosensors have many advantages such as miniaturization, standardization, and mass-production. In this work, we have fabricated metal-oxide-semiconductor (MOS) FET that operates as molecular recognitions based electronic sensor. Measurements were taken with the devices under phosphate buffered saline solution. The drain current ($I_{D}$) was decreased after forming self-assembled mono-layers (SAMs) used to capture the protein, which resulted from the negative charges of SAMs, and increased after forming protein by 11.5% at $V_{G}$ = 0 V due to the positive charges of protein.

• 한국정보전자통신기술학회논문지
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• 제8권1호
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• pp.37-44
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• 2015

본 논문에서 전계효과 트랜지스터 (field effect transistor; FET) 제작을 위한 표면 프로그램된 aminopropylethoxysilane(APTES)와 1-octadecyltrichlorosilane(OTS) 패턴을 이용하여 단일벽 탄소 나노튜브(single-walled carbon nanotube; SWCNT)를 실리콘 기판 위에 선택적으로 흡착시키는 공정방법을 제안하였다. 양성 표면 분자 패턴을 만들기 위해 형성된 APTES 패턴은 많은 양의 SWCNT의 흡착을 위해 제작되었고, OTS 만을 이용한 공정보다 효과적인 SWCNT 흡착이 가능하다. 산화막(silicon dioxide)이 형성된 실리콘 기판 위에 사진공정(photolithography process)을 이용하여 임의의 감광액(photoresist; PR) 패턴이 형성되었다. PR 패턴이 형성된 기판은 헥산 용매를 이용하여 1:500 (v/v)로 희석된 OTS 용액 속에 담가진다. OTS 박막이 표면 전체에 만들어지고, PR 패턴이 제거되는 과정에서 PR 위에 형성되었던 OTS 박막도 같이 제거되어, 선택적으로 형성된 OTS 박막 패턴을 얻을 수 있다. 이 기판은 다시 에탄올 용매를 이용하여 희석된 APTES 용액 속에 담가진다. APTES 박막은 OTS 박막 패턴이 없는 노출된 산화막 위에 형성된다. 마지막으로 이처럼 APTES와 OTS에 의해 표면 프로그램된 기판은 SWCNT가 분산된 다이클로로벤젠(dichlorobenzene) 용액 속에 담가진다. 결과적으로 SWCNT는 양 극성을 띠는(positive charged) APTES 박막 패턴 위에만 흡착된다. 반면 중성O TS 박막 패턴 위에는흡착되지 않는다. 이러한 표면 프로그램 방법을 사용하여 SWCNT는 원하는 영역에 자기 조립시킬 수 있다. 우리는 이 방법을 이용하여 소오스와 드레인 전극사이에 SWCNT가 멀티 채널로 구성된 다중채널 FET를 성공적으로 제작하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.44-47
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• 2000

본 연구는 α-Si:H TFT(Amorphous Silicon Thin Film Transistor)를 대체 할 펜타센을 활성층으로 사용하는 박막 트랜지스터를 제작에 관한 것이다. 유기 박막 트랜지스터는 유기발광소자와 함께 유연한 디스플레이에 응용된다. 펜타센 박막 트랜지스터의 제작은 채널 길이 25㎛, 70㎛, 소스, 드레인, 게이트 전극으로 Au을 lift off 공정으로 제작하였으며, 펜타센은 OMBD(Organic Molecular Beam Deposition)로 기판온도를 80℃로 유지하여 증착하였다. 제작된 소자로부터 트랜지스터 전류-전압 특성곡선을 측정하였고, 게이트에 의한 채널의 전도도가 조절됨을 확인하였다. 그리고, 전달특성곡선으로부터 문턱전압과 전계효과 이동도를 추출하였다.

• Journal of Information Display
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• 제6권3호
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• pp.6-11
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• 2005

In this paper, a general performance of the PSS-LCD or Polarization Shielded Smectic Liquid Crystal Display is discussed. This smectic base LCD does not use any spontaneous polarization, but uses induced polarization just sa me with current nematic base LCDs. Specific initial molecular alignment as well as specific cell design realizes ext remely fast optical response speed with native wide viewing angle. Moreover, this performance is provided by full compatible electronics for current conventional LCDs. A general performance of the PSS-LCD is introduced herein.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.299-304
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• 2003

We discuss several key technologies of liquid crystal displays (LCDs) that share common features of all organic displays (AODs). An overview of the morphological effects associated with molecular ordering at interfaces on the Crystallinity and the carrier mobility in organic thin film transistors (OTFTs) is given from the viewpoint of the alignment mechanism for LCDs. Recent progress of improving the carrier mobility in the OTFTs is also reviewed.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.261-264
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• 2000

Organic light emitting diodes(OLEDs) have been expected to find an application as a new type of display since C. W. Tang and VanSlyke first reported on high performance OLEDs. This paper has been stuied a green organic EL device using dye doped emitting layer such as C6(Coumarin 6). In the Alq-based e]ectroluminescence diodes, we applied highly fluorescent molecular(Coumarin 6) and obtained enhancement in the electroluminescence efficiency.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.21-24
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• 2001

We studied aluminum cluster deposition using molecular dynamics simulation. We investigated the variations of the cluster momentum and the impulse force during collisions, and found that the close-packed cluster impact has some of properties of the single particle collision and the linear chain collisions. We also simulated the series of energetic cluster deposition with energy Per atom. When energy Per atom in cluster has some eV rather than very low, the intermixing occurred easily in growth film and we can obtain a good film without subsequent annealing process.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.169-172
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• 2001

We have investigated the mechanical deformation of carbon nanotube using TBMD(tight-binding molecular dynamics) simulation. We have studied four carbon nanotubes, armchair (6, 6), (7, 7), (8, 8), and (9, 9) carbon nanotubes whose length were same. As a result of study, we have known that the nanotube's yield force increases with incresing their diameter. It is similar between (6, 6) and (8, 8) CNT's force-strain curves. Also force-strain curve between (7,7) and (9, 9) CNTs are nearly same.