• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2002.11a
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• pp.14-19
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• 2002

In this study, as Cu diffusion barrier, tantalum nitrides were successfully deposited on Si(100) substrate and SiO2 by plasma assisted atomic layer deposition(PAALD) and thermal ALD, using pentakis (ethylmethlyamino) tantalum (PEMAT) and $NH_3$ as precursors. The TaN films were deposited on $250^{\circ}$C by both method. The growth rates of TaN films were $0.8{\AA}$/cycle for PAALD and $0.75{\AA}$/cycle for thermal ALD. TaN films by PAALD showed good surface morphology and excellent step coverage for the trench with an aspect ratio of h/w - $1.8 : 0.12 \mu\textrm{m}$ but TaN films by thermal ALD showed bad step coverage for the same trench. The density for PAALD TaN was $11g/\textrm{cm}^3$ and one for thermal ALD TaN was $8.3g/\textrm{cm}^3$. TaN films had 3 atomic % carbon impurity and 4 atomic % oxygen impurity for PAALD and 12 atomic % carbon impurity and 9 atomic % oxygen impurity for thermal ALD. The barrier failure for Cu(200nm)/TaN(l0nm)/$SiO_2(85nm)$/Si structure was shown at temperature above $700^{\circ}$C by XRD, Cu etch pit analysis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.4
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• pp.238-243
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• 2018

A nanofiber was fabricated with carbon nanotubes for transparent electrodes. It was prepared with a composite solution of bio-molecules polycaprolactone (PCL) and multiwalled carbon nanotubes (MWCNTs) by electrospinning on a glass substrate, following which its electrical characteristics were investigated. The content of MWCNTs was varied during electrospinning, while that of PCL was fixed. Further, a nanometer-thick thin film of silver was deposited on the nanofiber layer using a thermal evaporator to improve the electrical characteristics; the sheet resistance significantly reduced after this deposition. The results showed that this carbon nanotube nanofiber has potential applications in biotechnology and as a flexible transparent display material.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.946-951
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• 2008

The opd gene, encoding organophosphorus hydrolase (OPH) from Flavobacterium sp. capable of degrading a wide range of organophosphate pesticides, was surface- and intracellular-expressed in Synechococcus PCC7942, a prime example of photoautotrophic cyanobacteria. OPH was displayed on the cyanobacterial cell surface using the truncated ice nucleation protein as an anchoring motif. A minor fraction of OPH was displayed onto the outermost surface of cyanobacterial cells, as verified by immunostaining visualized under confocal laser scanning microscopy and OPH activity analysis; however, a substantial fraction of OPH was buried in the cell wall, as demonstrated by proteinase K and lysozyme treatments. The cyanobacterial outer membrane acts as a substrate (paraoxon) diffusion barrier affecting whole-cell biodegradation efficiency. After freeze-thaw treatment, permeabilized whole cells with intracellular-expressed OPH exhibited 14-fold higher bioconversion efficiency ($V_{max}/K_m$) than that of cells with surface-expressed OPH. As cyanobacteria have simple growth requirements and are inexpensive to maintain, expression of OPH in cyanobacteria may lead to the development of a low-cost and low-maintenance biocatalyst that is useful for detoxification of organophosphate pesticides.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.356-357
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• 2006

Tin oxide thin films have been prepared on display glass from mixtures of dibutyl tin diacetate as a tin source, oxygen as an oxidant by Plasma Enhanced Chemical Vapor Deposition (PECVD) method. The relationships between the properties of tin oxide thin films and various reaction parameters such as the deposition temperature, deposition time and the oxygen gas flow rate were studied. As the deposition temperature increased, the texture plane of $SnO_2$ changed from (200) plane to denser (211) and (110) planes. Lower deposition temperature and thinner thickness of deposited film led to decreasing grain size, surface roughness and electrical resistivity of the formed thin films at $325{\sim}425^{\circ}C$. The properties of fabricated $SnO_2$ films are highly changed with variations of substrate temperature and deposition time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.189-192
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• 2005

We have investigated the EO characteristics generation of pretilt angle for a nematic liquid crystal (NLC) alignment with photoalignment method on three kinds of photopolymer surfaces using polymer substrates. The LC homogeneous alignment were observed on the PMI3CA (N-(phenyl)maleimide with 3-carbon chain cinnamoyl group) and PMIF (N-(phenyl)maleimide including fluoro cinnamoyl group). However, the homeotropic alignment on the PMI5CA(N-(phenyl)maleimide with 5-carbon chain cinnamoyl group) was obtained. Also, EO characteristics of the flexible photoaligned TN-LCD using PMIF surface are better than that of the flexible TN-LCD using PMI3CA surface. Also, the stable EO performances of flexible photoaligned VA-LCD using the PMI5CA surface was observed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.531-531
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• 2007

현재 널리 사용되고 있는 X선 영상 검출기의 문제점을 해결하기 위해 새로운 연구가 활발히 진행되고 있다. 본 논문에서는 새로운 X선 검출기로써의 가능성 제시를 위해 Display용 PDP(Plasma Display panel)를 디지털 X-ray Detector로 적용하기 위한 기본적인 X-ray에 대한 반응성을 검증하였다. PDP의 X-ray Detector로의 사용 가능성을 보기 위하여, 실험에 사용된 panel은 상용화된(commercial) Display용 PDP의 기본적인 구조와 똑같은 구조의 sample을 제작하여 사용하였다. 제작된 panel은 상판에 Substrate glass와 유전체층, 투명전극을 형성하고, 버스 전극층과 MgO층을 형성하였다. 하판에는 격벽을 제작하고 형광체(R.G.B)층을 형성하고, 어드레스 전극을 형성하여 기존의 Display용 PDP와 똑같은 구조를 지니게 하였다. 이렇게 제작된 panel의 X-선 검출기로서의 전기적 특성물 조사하기 위해 누설전류(Dark current), X선 민감도(X-ray sensitivity), 그리고 선형특성(Linearity)을 측정하였다. 측정 결과, 누설전류가 낮고 X-선 검출기로서의 가능성이 충분한 민감도를 보이며, 선형적 특성 또한 우수한 결과를 보이는 등 안정된 전기적 동작특성을 보였다. 이러한 결과로부터 기존에 사용되어오던 디스플레이용 PDP의 구조적 변경을 통하여 상용화된 PDP룰 디지털 X-선 검출기로서의 적용 가능성을 확인할 수 있었다.

• Laser Solutions
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• v.11 no.2
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• pp.26-32
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• 2008

Micro lens array (MLA) is widely used in information technology (IT) industry fields, for examples such as a projection display, an optical power regulator, a micro mass spectrometer and for medical appliances. Recently, MLA have been fabricated and developed by using a reflow method, micro etching, electroplating, micromachining and laser local heating. Laser local thermal-expansion (LLTE) technology demonstrates the formation of microdots on the surface of polymer substrate, in this paper. We have also investigated the new direct fabrication method of placing the MLA on the surface of a SU-8 photoresist layer. We have obtained the 3D shape of the micro lens processed by UV laser irradiation and have experimentally verified the optimal process conditions.

• Advances in materials Research
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• v.2 no.4
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• pp.181-193
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• 2013

Description and theory of spin coating technique has been elaborately outlined and a spin coating machine designed and fabricated using affordable components. The system was easily built with interdisciplinary knowledge of mechanics, fluid mechanics and electronics. This equipment employs majorly three basic components and two circuit units in its operation. These include a high speed dc motor, a proximity sensor mounted at a distance of about 15 mm from a reflective metal attached to the spindle of the motor to detect every passage of the reflective metal at its front and generate pulses. The pulses are transmitted to a micro-controller which process them into rotational speed (revolution per minute) and displays it on a lead crystal display (LCD) which is also a component of the micro-controller. The circuit units are a dc power supply unit and a PWM motor speed controlling unit. The various components and circuit units of this equipment are housed in a metal casing made of an 18 gauge black metal sheet designed with a total area of 1, $529.2cm^2$. To illustrate the use of the spin-coating system, ZnO sol-gel films were prepared and characterized using SEM, XRD, UV-vis, FT-IR and RBS and the result agrees well with that obtained from standard equipment and a speed of up to 9000 RPM has been achieved.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.04a
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• pp.369-372
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• 2010

평판 디스플레이(flat panel display)의 크기가 커짐에 따라 다양한 기판을 이용한 제조 방법이 개발되고 있다. 디스플레이 제조 공정 중 기판의 결함을 찾아서 분류하는 검사 시스템은 최종 제품의 품질을 결정하는 매우 중요한 부분이다. 본 연구는 머신비전 기술을 이용하여 불투명하고 반사율이 높은 기판 표면의 결함을 찾아내고, 이 결함을 스크래치(scratch), 흑결함(dark defect), 백결함(white defect)으로 분류하는 장치를 구현하는데 목적이 있다. 이를 구현하기 위해 본 논문에서는 정밀 스테이지(stage)와 라인 카메라(line CCD camera)을 이용한 광학계를 활용하여 검사 시스템을 구현하였다. 구축된 시스템을 이용하여 취득한 이미지를 12 개의 영역으로 등분하여 각각의 국부 영역에 대한 문턱값 연산(thresholding)을 적용함으로써 조명의 불균일을 의한 검출 에러율을 획기적으로 낮추었다. 간단한 컴퓨터비전 알고리듬의 채용으로도 검사 시스템의 구현이 가능함을 보였다.

• Journal of Microbiology and Biotechnology
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• v.34 no.6
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• pp.1189-1196
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• 2024

Bacterial resistance to commonly used antibiotics is one of the major challenges to be solved today. Bacteriophage endolysins (Lysins) have become a hot research topic as a new class of antibacterial agents. They have promising applications in bacterial infection prevention and control in multiple fields, such as livestock and poultry farming, food safety, clinical medicine and pathogen detection. However, many phage endolysins display low bactericidal activities, short half-life and narrow lytic spectrums. Therefore, some methods have been used to improve the enzyme properties (bactericidal activity, lysis spectrum, stability and targeting the substrate, etc) of bacteriophage endolysins, including deletion or addition of domains, DNA mutagenesis, chimerization of domains, fusion to the membrane-penetrating peptides, fusion with domains targeting outer membrane transport systems, encapsulation, the usage of outer membrane permeabilizers. In this review, research progress on the strategies for improving their enzyme properties are systematically presented, with a view to provide references for the development of lysins with excellent performances.