• 한국미생물·생명공학회지
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• 제33권2호
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• pp.106-111
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• 2005

비금속성 이성화효소로 추정되는 Staphylococcus aureus의 tagatose-6-phosphate isomerase(E.C. 5.3.1.26)의 기질다 양성을 조사하기 위해서 그 구조유전자(lacB;510bp와 lacA;430bp)를 대장균에서 동시발현하였다. 알려진 기질 이외에 D-ribose와 D-allose에 대해 이성화활성이 새롭게 관찰되었다. EDTA 1 mM 존재하에서도 D-ribose와 D-allose에 대하여 각각 EDTA 비존재 조건에 대비하여 $95\%,\;75\%$의 이성화활성을 나타내는 것으로 미루어 tagatose-6-phosphate isomerase가 비금속성 이성화효소임을 밝혔다. 이때 lacA 또는 lacB의 단독발현시에는 이성화활성이 전혀 밝견되지 않았다. D-Ribose와 D-allose에 대한 기질친화상수 ($K_m$)은 각각 26 mM와 142 mM였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권6호
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• pp.422-430
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• 2000

Mechanism of lignin biodegradation caused by basidiomycetes and the history of lignin biodegradation studies were briefly reviewed. The important roles of fungal extracellular ligninolytic enzymes such as lignin and manganese peroxidases (LiP and MnP) were also summarized. These enzymes were unique in their catalytic mechanisms and substrate specificities. Either LiP or MnP system is capable of oxidizing a variety of aromatic substrates via a one-electron oxidation. Extracellular fungal system for aromatic degradation is non-specific, which recently attracts many people working a bioremediation field. On the other hand, an intracellular degradation system for aromatic compounds is rather specific in the fungal cell. Structurally similar compounds were prepared and metabolized, indicating that an intracellular degradation strategy consisted of the cellular systems for substrate recognition and metabolic response. It was assumed that lignin-degrading fungi might be needed to develop multiple metabolic pathways for a variety of aromatic compounds caused by the action of non-specific ligninolytic enzymes on lignin. Our recent results on chemical stress responsible factors analyzed using mRNA differential display techniques were also mentioned.

• 한국버섯학회지
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• 제17권3호
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• pp.85-92
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• 2019

Over a million tons of spent mushroom substrate (SMS) are generated as by-products of mushroom cultivation every year in Korea. Disposal of SMS by mushroom farmers is difficult, therefore, recycling solutions that do not harm the environment are necessary. SMS consists of mushroom mycelia and residues of fruiting bodies, containing a variety of bioactive substances, such as extracellular enzymes, antimicrobial compounds, and secondary metabolites. This paper reviews utility of SMS for bioremediation, controlling plant disease, and production of lignocellulytic enzymes, organic fertilizer, and animal feed.

• 한국진공학회지
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• 제4권2호
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• pp.172-176
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• 1995

$YBa_2Cu_3O_{7-y}$ thin films have been prepared on MgO(100)substrates placed on-axis to the target by dc magnetron sputtering in a variety of oxygen/argon gas pressures with different substrate-target distances. We found that films with the c-axis perpendicular to the substrate deposited in an optimally high gas pressure with on-axis substrate-target configuration do. Increasing the substrate-target distance was found to be effetive in reducing the resputtering effect and enhancing superconductivity of films, but not so much $\alpha$-and c-axis growth of YMCO films on MgO substrates. Dependences of the Tc, the rationj of resistances at 300K and 100K, and the X-ray diffraction pattern on the gas pressure and the substrate target distance are described.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.413-413
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• 2007

In recent years, flexible display devices such as liquid crystal display (LCD), organic light emitting diode (OLED), etc. have attracted considerable interest in a wide variety of applications. Polymer substrate is absolutely necessary to realize this kind of flexible display devices. Using the polymer as a substrate, there are lots of advantages including not only mechanical flexibility such as rolling and bending characteristics but also light weights, low cost and so on. In detail, thickness and weights is only one forth and one second of glass substrate, respectively. However, it needs low temperature below $150^{\circ}C$ in the fabrication process comparing to conventional deposition process. The polymer substrate is not thermally stable as much as the glass substrate so that some deformation can be occurred according to variation of temperature. In particular, performance of devices can be easily deteriorated by shrinkage of substrate when heating it. In this paper, pre-annealing and deposition of buffer layer was introduced and studied to solve previously mentioned problems of the shrinkage and followed shear stress.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.202-205
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• 2002

Polycrystalline silicon thin film transistors (poly-Si TFTs) are used in a wide variety of applications, and will figure prominently future high-resolution, high-performance flat panel display technology However, it was very difficult to fabricate high performance poly-Si TFTs at a temperature lower than 300$^{\circ}C$ for glass substrate. Conventional process on a glass substrate were limited temperature less than 600$^{\circ}C$ This paper proposes a high temperature process above 750$^{\circ}C$ using a flexible molybdenum substrate deposited hydrogenated amorphous silicon (a-Si:H) and than crystallized a rapid thermal processor (RTP) at the various temperatures from 750$^{\circ}C$ to 1050$^{\circ}C$. The high temperature annealed poly-Si film illustrated field effect mobility higher than 30 $\textrm{cm}^2$/Vs, achieved I$\sub$on//I$\sub$off/ current ratio of 10$^4$ and crystall volume fraction of 92%. In this paper, we introduce the new TFTs Process as flexible substrate very promising roll-to-roll process, and exhibit the properties of high temperature crystallized poly-Si Tn on molybdenum substrate.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.232.2-232.2
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• 2014

Since its discovery in 2004, graphene, a sp2-hybridized 2-Dimension carbon material, has drawn enormous attention. A variety of approaches have been attempted, such as epitaxial growth from silicon carbide, chemical reduction of graphene oxide and CVD. Among these approaches, the CVD process takes great attention due to its guarantee of high quality and large scale with high yield on various transition metals. After synthesis of graphene on metal substrate, the subsequent transfer process is needed to transfer graphene onto various target substrates, such as bubbling transfer, renewable epoxy transfer and wet etching transfer. However, those transfer processes are hard to control and inevitably induce defects to graphene film. Especially for wet etching transfer, the metal substrate is totally etched away, which is horrendous resources wasting, time consuming, and unsuitable for industry production. Thus, our group develops one-step process to directly grow graphene on glass substrate in plasma enhanced chemical vapor deposition (PECVD). Copper foil is used as catalyst to enhance the growth of graphene, as well as a temperature shield to provide relatively low temperature to glass substrate. The effect of growth time is reported that longer growth time will provide lower sheet resistance and higher VSG flakes. The VSG with conductivity of $800{\Omega}/sq$ and thickness of 270 nm grown on glass substrate can be obtained under 12 min growing time. The morphology is clearly showed by SEM image and Raman spectra that VSG film is composed of base layer of amorphous carbon and vertically arranged graphene flakes.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 The Pacific Aisan Confrence On Intelligent Systems 2001
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• pp.224-229
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• 2001

When a semiconductor package is assembled, various materials such as die attach adhesive, lead frame, EMC (Epoxy Molding Compound), and gold wire are used. For better preconditioning performance, the combination between the packaging materials by studying the compatibility of their properties as well as superior packaging material selection is important. But it is not an easy task to find proper packaging material sets, since a variety of factors like package design, substrate design, substrate size, substrate treatment, die size, die thickness, die passivation, and customer requirements should be considered. This research applies case-based reasoning(CBR) technique to solve this problem, utilizing prior cases that have been experienced. Our particular interests lie in building decision support model to aid the selection of proper die attach adhesive. The preliminary results show that this approach is promising.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.326-331
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• 2007

Large-scale molecular dynamics simulations are performed to verify the deformation characteristics of grain boundaries in nanolithography process. The copper substrate made of 200,000 atoms is constructed by two grains in different crystal orientations using dynamic relaxation method. The grain boundary is located in the middle of the substrate with $45\sim135$ degree angles. The plowing tip is made of diamond-like-carbon atoms in a variety of shapes. In the simulations, the generation, propagation, and accumulation of dislocations are observed inside the substrate. From the numerical results, we address the dynamic behavior of the grain boundaries as well as the frictional characteristics in terms of the morphology of initial grain boundaries.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.578-578
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• 2012

Graphene, a flat one-atom-thick two-dimensional layer of carbon atoms, is considered to be a promising candidate for nanoelectronics due to its exceptional electronic properties. Most of all, future nanoelectronics such as flexible displays and artificial electronic skins require low cost manufacturing process on flexible substrate to be integrated with high resolutions on large area. The solution based printing process can be applicable on plastic substrate at low temperature and also adequate for fabrication of electronics on large-area. The combination of printed electronics and graphene has allowed for the development of a variety of flexible electronic devices. As the first step of the study, we prepared the gate electrodes by printing onto the gate dielectric layer on PET substrate. We showed the performance of graphene field-effect transistor with electrohydrodynamic (EHD) inkjet-printed Ag gate electrodes.