• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.367-372
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• 2000

ZnO thin films were deposited on amorphous slide glass and $SiO_2$/Si substrates by Facing Targets Sputtering method with sputtering current 0.1~0.8 A, working pressure 0.5~3 mTorr and substrate temperature R.T~$400^{\circ}C$. When the sputtering current was 0.4 A, working pressure was 0.5 mTorr and substrate temperature was 30$0^{\circ}C$, ${\Delta}{\Theta}_{50}$ value of ZnO/glass and ZnO/$SiO_2$/si thin film was $3.8^{\circ}$ and $2.98^{\circ}$, respectively. In these conditions, we knew that ZnO thin film were deposited with good c-axis orientation on amorphous slide glass by FTS system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.3
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• pp.256-267
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• 2019

Styrofoam beads, which are relatively inexpensive and can provide a large specific surface area, were tested as filter media. Styrofoam beads with a diameter of $3{\pm}0.5mm$ were used; the specific surface area of the beads was $1,034m^2{\cdot}m^{-3}$. Five independent recirculating culture systems were used in the experiment. Each system consisted of one culture tank and three trickling bio-filters. Using the systems, nitrification efficiency was evaluated with respect to hydraulic loading rate (HLR) and carbon/nitrogen (C/N) ratio. The lowest ammonia and nitrogen concentrations were $0.84mg{\cdot}L^{-1}$ and $1.30mg{\cdot}L^{-1}$, respectively, observed at an HLR of $50.9m^3{\cdot}m^{-2}{\cdot}h^{-1}$. Nitrification efficiency in the culture tank was highest at a C/N ratio of 0, with ammonia and nitrite nitrogen concentrations of $0.32mg{\cdot}L^{-1}$ and $0.90mg{\cdot}L^{-1}$, respectively. Ammonia and nitrite nitrogen concentrations in the culture tank abruptly changed at C/N ratios ${\geq}3$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.385-386
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• 2008

This paper reports the design of the ultra low power consumption microhotplates for high temperatures. The microhotplates consisting of a platinum-based heating element on AlN/poly 3C-SiC layers were designed. The microhotplate is a $600\times600{\mu}m^2$ square shaped membrane made of $1{\mu}m$ thick ploy 3C-SiC suspended by four legs. The microhotplate was compared with $Si_3N_4/SiO_2/Si_3N_4$(NON) structure microhotplate by COMSOL simulation system. Thermal uniformity, power consumption and thermal characterizations of microhotplates based on 3C-SiC thin film are better than microhotplates with NON structure.

• Journal of the Korean Society for Heat Treatment
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• v.4 no.1
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• pp.13-18
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• 1991

The formation of high $T_c$ phase is very sluggish and c parameter of unit cell of high $T_c$ phase is about $37{\AA}$. High $T_c$ oxide superconductor with a $T_c$ above 100 K has been successfully prepared by solid state reaction method in BiSrCaCuO system by Pb adding. The microstructure related to the formation of the high $T_c$ phase has been investigated. As compared with YBCO compound, the formation reaction of the high $T_c$ requires long time heat treatment. It is due to the transformation from the low $T_c$ phase to high $T_c$ phase. The sintering just below the melting point of the calcined powder mixture is effective on the formation of the high $T_c$ phase in Pb-added BiSrCaCuO system. The growth of the high $T_c$ superconducting phase has a thin plate shape, which is characterized by the c parameter of $37{\AA}$. The formation of the high $T_c$ phases is delayed by the excessive addition of Pb. The lattice parameter(c) of the unit cell (both the low and high $T_c$ phases) is increased with increase of Pb.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.603-604
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• 2009

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.178-181
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• 2005

Quaternary Ti-Si-C-N coatings were deposited on WC-Co substrates by a hybrid coating system of arc ion plating (AIP) and sputtering techniques using Ti and Si targets, in an $Ar/N_2/CH_4$ gaseous mixture. The crystallinity, bending status, and microstructure of the Ti-Si-C-N coatings were measured by X-ray diffractometer (XRD) and X-ray photoelectron spectroscope (XPS), The micro-hardness of Ti(C,N) and Ti-Si-N coatings were about 30 and 40 GPa, respectively. As the Si was incorporated into Ti(C,N) coatings, the Ti-Si-C-N coatings having Si content of $8.9\;at.\%$ showed the maximum hardness value of about 55 GPa. In this work, the microstructure and mechanical properties of Ti-Si-C-N coatings were systematically investigated.

• Journal of Veterinary Science
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• v.22 no.6
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• pp.76.1-76.15
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• 2021

Background: The development of a vaccine for Jembrana disease is needed to prevent losses in Indonesia's Bali cattle industry. A DNA vaccine model (pEGFP-C1-tat) that requires a functional delivery system will be developed. Polylactic-co-glycolic acid (PLGA) may have potential as a delivery system for the vaccine model. Objectives: This study aims to evaluate the in vitro potential of PLGA as a delivery system for pEGFP-C1-tat. Methods: Consensus and codon optimization for the tat gene was completed using a bioinformatic method, and the product was inserted into a pEGFP-C1 vector. Cloning of the pEGFP-C1-tat was successfully performed, and polymerase chain reaction (PCR) and restriction analysis confirmed DNA isolation. PLGA-pEGFP-C1-tat solutions were prepared for encapsulated formulation testing, physicochemical characterization, stability testing with DNase I, and cytotoxicity testing. The PLGA-pEGFP-C1-tat solutions were transfected in HeLa cells, and gene expression was observed by fluorescent microscopy and real-time PCR. Results: The successful acquisition of transformant bacteria was confirmed by PCR. The PLGA:DNA:polyvinyl alcohol ratio formulation with optimal encapsulation was 4%:0.5%:2%, physicochemical characterization of PLGA revealed a polydispersity index value of 0.246, a particle size of 925 nm, and a zeta potential value of -2.31 mV. PLGA succeeded in protecting pEGFP-C1-tat from enzymatic degradation, and the percentage viability from the cytotoxicity test of PLGA-pEGFP-C1-tat was 98.03%. The PLGA-pEGFP-C1-tat demonstrated luminescence of the EGFP-tat fusion protein and mRNA transcription was detected. Conclusions: PLGA has good potential as a delivery system for pEGFP-C1-tat.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.891-896
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• 2003

Novel fabrication technique was developed for high strength Reaction-Bonded SiC (RBSC) hot gas filter for use in IGCC (Integrated Gasification Combined Cycle) system. The room and high temperature fracture strengths for Si-melt infiltrated reaction-bonded SiC were 50-123, and 60-66 MPa, respectively. The average pore size was 60-70 $\mu\textrm{m}$ and the porosity was about 34 vol％. RBSC infiltrated with molten silicon showed improved fracture strength at high temperature, as compared to that of clay-bonded SiC, due to SiC/Si phase present within SiC phase. The thickness for SiC/Si phase was increased with increasing powder particle size of SiC from 10 to 34 $\mu\textrm{m}$. Pressure drop with dust particles showed similar response as compared to that for Schumacher type 20 filter. The filter fabricated in the present study showed good performance in that the filtered powder size was reduced drastically to below 1 $\mu\textrm{m}$ within 4 min.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.10a
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• pp.34-34
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• 1997

• KIPE Magazine
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• v.14 no.1
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• pp.26-33
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• 2009

광대역 반도체중에서도 SiC(Silicon Carbide)는 우수한 전기적, 기계적, 열적, 화학적, 광학적 그리고 생체 적합성 등으로 인하여 지난 반세기 동안 급속히 발전하고 있는 SiM/NEMS(Micro/Nano Electro Mechanical System)를 대처할 수 있는 차세대 M/NEMS로써 고온, 고압, 고진동, 고습도 등의 극한 환경에서도 사용 가능한 자동차, 선박, 우주항공, 산업 프랜트용 마이크로 센서 및 액츄에이터, 초고주파수 정보통신용 부품 그리고 바이오 센서 등의 분야에 크게 주목을 받고 있다. 본 논문에서는 현재 SiC M/NEMS의 연구개발 현황에 대해서 소개하고자 한다.