• 한국미생물·생명공학회지
• /
• 제40권4호
• /
• pp.403-408
• /
• 2012

본 연구에서는 용액 중 플라즈마 공정을 이용하여 젤라틴/Ag 나노입자(AgNP) 용액을 제조하고 동결 건조하여 3차원 비계 형태의 생체복합재료를 성공적으로 제조하였다. 본 공정에서는 환원제 사용 없이 플라즈마 방전 중 수소 라디칼과 Ag 이온의 환원을 통해, 젤라틴 기지재 내에 지름 12~20 nm 크기의 구형 AgNP가 효과적으로 형성되었다. 젤라틴 농도가 높을수록(3%) AgNP의 분산안정성이 좋았으며, 3차원 비계 형태의 젤라틴의 미세공 조직이 작아지고 밀도가 높아지는 것으로 나타났다. 또한 AgNP의 농도가 높을수록(5 mM) 항균효과가 좋았는데, Ag5G3 생체복합재료를 사용했을 때 황색포도상구균의 생장은 44% 감소되었고, 대장균의 생장은 100% 감소되어 그람 음성균에 대한 항균력이 더 좋은 것으로 나타났다.

• 조명전기설비학회논문지
• /
• 제22권2호
• /
• pp.71-79
• /
• 2008

철도 고압배전선로의 경우 궤도를 따라 양방향으로 선로연변에 통신 및 신호설비와 병행하여 가공 또는 지중선로로 설치되어 있다. 가공선로의 경우에는 대기중에 노출되어 있어 뇌격, 폭풍우, 염해 등 자연현상으로 인한 고장발생이 다수 발생하고 있으며, 이에 따른 보호장치의 오 부동작이 빈번하게 발생하고 있다. 철도 고압배전선로에서 발생하는 사고 중 가장 많은 것은 1선 지락이지만 이밖에 선간 단락, 심할 경우에는 3선 지락(단락)으로까지 진전되는 사고가 있을 뿐만 아니라 단선 사고까지 발생하는 경우도 있다. 따라서 사고를 방지하기 위해서는 보다 상세한 점검보수가 필요하며, 고장발생시 조기발견과 신속한 고장처리는 철도안전수송에 중요하다. 본 논문에서는 철도 고압배전계통의 주류를 이루게 될 22.9[kV] 직접접지 계통을 대상으로 고장 발생시 고장 위치를 신속하게 표정할 수 있는 고장점 표정 알고리즘 개발을 위해 22.9[kV] 고압배전계통을 모델링 하여 특성해석과 고장해석을 수행하였고, 정확한 고장점 표정이 가능한 반복계산법을 이용한 알고리즘을 제시하였으며, 사례연구를 통해 성능을 입증하였다.

• Journal of Microbiology and Biotechnology
• /
• 제19권7호
• /
• pp.718-726
• /
• 2009

The objective of this study was to develop and validate secondary models that can predict growth parameters of L. monocytogenes Scott A as a function of concentrations (0-3%) of a commercial potassium lactate (PL) and sodium diacetate (SDA) mixture, pH (5.5-7.0), and temperature (4-37DC). A total of 120 growth curves were fitted to the Baranyi primary model that directly estimates lag time (LT) and specific growth rate (SGR). The effects of the variables on L. monocytogenes Scott A growth kinetics were modeled by response surface analysis using quadratic and cubic polynomial models of the natural logarithm transformation of both LT and SGR. Model performance was evaluated with dependent data and independent data using the prediction bias ($B_f$) and accuracy factors ($A_f$) as well as the acceptable prediction zone method [percentage of relative errors (%RE)]. Comparison of predicted versus observed values of SGR indicated that the cubic model fits better than the quadratic model, particularly at 4 and $10^{\circ}C$. The $B_f$and $A_f$for independent SGR were 1.00 and 1.08 for the cubic model and 1.08 and 1.16 for the quadratic model, respectively. For cubic and quadratic models, the %REs for the independent SGR data were 92.6 and 85.7, respectively. Both quadratic and cubic polynomial models for SGR and LT provided acceptable predictions of L. monocytogenes Scott A growth in the matrix of conditions described in the present study. Model performance can be more accurately evaluated with $B_f$and $A_f$and % RE together.

• IMMUNE NETWORK
• /
• 제6권4호
• /
• pp.192-198
• /
• 2006

Background: Investigating strategy to enhance efficiency of gene transfer via adenovirus is critical to sustain gene expression in targeted cells or tissues to regulate immune responses. However, the use of adenovirus as a gene delivery method has been limited by the native tropism of the virus. In this study, the critical parameter is to improve the efficient binding of viral particles to the plasma membrane prior to cellular uptake. Methods: Human immunodeficiency virus (HIV-1) trans-acting activator of transcription (TAT), a protein transduction domain, was fused to the ectodomain of the coxsackie-adenovirus receptor (CAR). The CAR-TAT protein was produced from a Drosophila Schneider 2 cells (S2) transfected with CAR-TAT genes. The function of CARTAT was analyzed the efficiency of adenoviral gene transfer by flow cytometry, and then immunizing AdVGFP with CAR-TAT was transduced on dendritic cells (DCs). Results: S2 transfectants secreting CAR-TAT fusion protein has been stable over a period of 6 months and its expression was verified by western blot. Addition of CAR-TAT induced higher transduction efficiency for AdVGFP at every MOI tested. When mice were vaccinated with DC of which adenoviral transduction was mediated by CAR-TAT, the number of IFN-${\gamma}$ secreting T-cells was increased as compared with those DCs transduced without CAR-TAT. Conclusion: Our data provide evidence that CAR-TAT fusion protein enhances adenoviral transduction and immunogenecity of transgenes on DCs and may influence on the development of adenoviral-mediated anti-tumor immunotherapy.

• 전자공학회논문지CI
• /
• 제37권1호
• /
• pp.55-63
• /
• 2000

본 논문은 영상 프레임간 차분 성분을 이용한 3D-DCT의 부영역 분할에 따르는 압축효과를 고찰하였다. 제안한 알고리즘은 연속되는 9개의 프레임 그룹단위를 이용하여 8개의 차분 성분을 큐빅블록(8${\times}$8${\times}$8) 형태로 나타낸 정보를 3차원 DCT를 취한 후 부대역으로 분할하려 압축하는 방법이다. 프레임간 시${\cdot}$공간의 주파수 성분을 가지고 8개의 차분 프레임을 DCT한 주파수 영역에서 영상 정보는 저주파 영역인 큐빅블록의 모서리 부분에 집중하므로 효율적인 압축데이터를 얻기 위해 시간축 방향의 프레임 성분블록( 8${\times}$8 블록)을 4${\times}$4 부블록으로 나누었다. 여기서, 이 부블록의 가중치를 이용하여 저주파 부분에 대한 가변적 부영역을 적용시켜 압축율을 높였다. 모의실험에서 비교적 단순한 영상과 고주파 성분을 많이 포함하는 복잡한 영상을 이용하여 복원된 영상의 해상도와 압축율로 비교 평가하였다. 그 결과 평균 0.04-0.05bpp의 압축범위에서 각각의 영상에 대하여 평균적으로 34.75dB와 30.36dB의 높은 압축효과를 얻을 수 있었다.

• 한국환경보건학회:학술대회논문집
• /
• 한국환경보건학회 2003년도 Challenges and Achievements in Environmental Health
• /
• pp.187-191
• /
• 2003

In this study, biomonitoring methods were developed to measure BTEXs exposure level in the air, metabolites of benzene and toluene in human urine, individual susceptibility markers in human blood for evaluation of the health effects about environmental pollution. We have also performed a small-scaled molecular epidemiology study on residents in Chuncheon and workers in workplace for these method applications. The workers in workplace were surveyed as study areas, and the residents in Chuncheon which is in the suburban area were surveyed as comparative areas in this study. Actually, 31 workers in as target group and 33 residences in as control group this epidemiological study. The results obtained from this study were as follows: 1. Benzene is a well-known carcinogen, it's median concentrations were 0.00024∼0.02057ppm at suburban area and 0.002∼00.654ppm at work place, These benzene concentrations were not exceed the OSHA(Occupational Safety and Health Administration) threshold benzene level of 1ppm in the states. 2. Metabolites product of benzene(t,t-Muconic Acid) and toluene(Hippuric Acid) were not significant both in suburban and workplace area. The median concentration of t,t-MA and HA were 0.0122, 1.44277g/g creatinine, respectively. 3. In the case of individual susceptibility markers as CYPlAl, 41.8% of them has homozygous wild type(W) and who has heterozygous variant type(H) was 35.4% and 22.8% of homozygous variant type(M) genetic type. In the case of CYP2E1, 62.82% of them has homozygous wild type(D) type, 34.62% of each has heterozygous variant type (DC) and 2.56% of them has homozygous variant type (CC). Who doesn't have GSTM1 gene was 46.25% and who has GSTM1 gene was 53.75％. Who doesn't have GSTT1 gene was 40.0％ in study groups and who has GSTT1 gene was 60.0%. Who has W genetic type, which is homozygous wild type of GSTP1, was 69.18% and H genetic type, which is heterozygous variant type was 28.4%. M genetic type which is homozygous variant type was 2.4%. 4. Concentration differences of metabolites such as t,t-MA and HA in urine, which is generated by individual susceptibility marker of GSTM1, GSTT1, GSTP1 gene of Phase I and CYP1A1, CYP2E1 gene of Phase II, was examined. As a result, GSTP1 and GSTM1 indicate slight differences depend on the amount of metabolites in urine, it was not statistically significant.

• 지구물리와물리탐사
• /
• 제21권1호
• /
• pp.8-14
• /
• 2018

저수지 제체에 대한 자연재해 피해를 예방하고 보수 및 보강대책을 수립하기 위해서 각종 계측기와 재해예방 전기비저항 모니터링 시스템을 설치하여 관리하고 있다. 대부분 30년 이상으로 노후화된 저수지는 농업용 관개에 따른 구조적인 취약성을 가지고 있다. 계측 및 모니터링 목적은 저수지의 안전성과 견고성을 확보하는데 있는데, 전기비저항탐사는 결함 부위, 침투수 이상대 및 제체 내 세굴현상 등과 같은 잠재적인 취약성 파악이 가능하다. 국내 한 저수지 제체 댐마루에 설치된 전기비저항 자동계측시스템을 통하여 매일 6시간 간격으로 저장된 연간 모니터링 자료를 이용하여, 제체 내 침투수 영향을 파악하였다. 연간 저수위 변화는 10m 정도인데, 영농기 취수에 따른 저수위 변화는 제체 내 물성변화를 야기한다. 모니터링 자료 해석 결과, 비저항 값은 연간 저수위 및 계절영향 이외에 대체로 안정적이었다. 또한, 제체 내 취수시설 주변의 취약성 고찰을 위해서 단순화된 모델을 구성하여 모델링을 수행하였다. 그 결과 전기비저항 모델 반응 계산을 통한 복통구조물 주변 침투수 구간의 탐지가 가능함을 확인하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
• /
• pp.211-211
• /
• 1999

Titanium nitride (TiN) thin films have useful properties including high hardness, good electrical conductivity, high melting point, and chemical inertness. The applications have included wear-resistant hard coatings on machine tools and bearings, decorative coating making use of the golden color, thermal control coatings for widows, and erosion resistant coatings for spacecraft plasma probes. For all these applications as feature sizes shrink and aspect ratios grow, the issue of good step coverage becomes increasingly important. It is therefore essential to manufacture conformal coatings of TiN. The growth of TiN thin films by chemical vapor deposition (CVD) is of great interest for achieving conformal deposition. The most widely used precursor for TiN is TiCl4 and NH3. However, chlorine impurity in the as-grown films and relatively high deposition temperature (>$600^{\circ}C$) are considered major drawbacks from actual device fabrication. To overcome these problems, recently, MOCVD processes including plasma assisted have been suggested. In this study, therefore, we have doposited Ti(C, N) thin films on Si(100) and D2 steel substrates in the temperature range of 150-30$0^{\circ}C$ using tetrakis diethylamido titanium (TDEAT) and titanium isopropoxide (TIP) by pulsed DC plamsa enhanced metal-organic chemical vapor deposition (PEMOCVD) method. Polycrystalline Ti(C, N) thin films were successfully grown on either D2 steel or Si(100) surfaces at temperature as low as 15$0^{\circ}C$. Compositions of the as-grown films were determined with XPS and RBS. From XPS analysis, thin films of Ti(C, N) with low oxygen concentration were obtained. RBS data were also confirmed the changes of stoichiometry and microhardness of our films. Radical formation and ionization behaviors in plasma are analyzed by optical emission spectroscopy (OES) at various pulsed bias and gases conditions. H2 and He+H2 gases are used as carrier gases to compare plasma parameter and the effect of N2 and NH3 gases as reactive gas is also evaluated in reduction of C content of the films. In this study, we fond that He and H2 mixture gas is very effective in enhancing ionization of radicals, especially N resulting is high hardness. The higher hardness of film is obtained to be ca. 1700 HK 0.01 but it depends on gas species and bias voltage. The proper process is evident for H and N2 gas atmosphere and bias voltage of 600V. However, NH3 gas highly reduces formation of CN radical, thereby decreasing C content of Ti(C, N) thin films in a great deal. Compared to PVD TiN films, the Ti(C, N) film grown by PEMOCVD has very good conformability; the step coverage exceeds 85% with an aspect ratio of more than 3.

• Asian-Australasian Journal of Animal Sciences
• /
• 제20권3호
• /
• pp.334-339
• /
• 2007

Reactive oxygen species (ROS) generate during electrical activation of oocytes which has detrimental effects on embryo survival when overwhelmed. The present study was designed to investigate the ability of L-ascorbic acid, a novel water soluble antioxidant, to reduce the ROS level in developing embryos and their subsequent effects on embryo development in vitro. The compact cumulus oocyte complexes (COCs) were cultured in tissue culture medium (TCM)-199 supplemented with 10 ng/ml epidermal growth factor, 4 IU/ml pregnant mare serum gonadotropin (PMSG), and human chorionic gonadotropin (hCG) and 10% (v/v) porcine follicular fluid (pFF) for 44 h. After maturation culture, the denuded oocytes were activated with a single DC pulse of 2.0 kV/cm in 0.3 M mannitol solution containing 0.5 mM of HEPES, 0.1 mM of $CaCl_2$ and 0.1 mM of $MgCl_2$ for $30{\mu}s$ using a BTX Electro-cell Manipulator. The activated oocytes were cultured in modified North Carolina State University-23 (mNSCU-23) medium for 168 h. The level of $H_2O_2$ in each embryo was measured by the dichlorohydrofluorescein diacetate (DCHFDA) method at 48 h after activation. The blastocyst formation rate was significantly higher when culture medium was supplemented with 50 and $100{\mu}M$ L-ascorbic acid (31.2 and 38.7%, respectively) compared to non-supplemented (16.1%) group. Accordingly, significantly more cells in blastocyst were found for 50 and $100{\mu}M$ L-ascorbic acid (50.0 and 56.4, respectively) compared to 0 and $200{\mu}M$ L-ascorbic acid (36.5 and 39.8, respectively). L-ascorbic acid reduces the $H_2O_2$ level in developing embryos in a dose-dependant manner. The $H_2O_2$ level (pixels/ embryos) was 191.5, 141.0, 124.0 and 163.3 for 0, 50, 100 and $200{\mu}M$ L-ascorbic acid, respectively. So, we recommend to supplement 50 or $100{\mu}M$ L-ascorbic acid in porcine in vitro culture medium.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2010년도 제39회 하계학술대회 초록집
• /
• pp.170-170
• /
• 2010

Thin-film transistors (TFT) have become the key components of electronic and optoelectronic devices. Most conventional thin-film field-effect transistors in display applications use an amorphous or polycrystal Si:H layer as the channel. This silicon layers are opaque in the visible range and severely restrict the amount of light detected by the observer due to its bandgap energy smaller than the visible light. Therefore, Si:H TFT devices reduce the efficiency of light transmittance and brightness. One method to increase the efficiency is to use the transparent oxides for the channel, electrode, and gate insulator. The development of transparent oxides for the components of thin-film field-effect transistors and the room-temperature fabrication with low voltage operations of the devices can offer the flexibility in designing the devices and contribute to the progress of next generation display technologies based on transparent displays and flexible displays. In this thesis, I report on the dc performance of transparent thin-film transistors using amorphous indium tin zinc oxides for an active layer. $SiO_2$ was employed as the gate dielectric oxide. The amorphous indium tin zinc oxides were deposited by RF magnetron sputtering. The carrier concentration of amorphous indium tin zinc oxides was controlled by oxygen pressure in the sputtering ambient. Devices are realized that display a threshold voltage of 4.17V and an on/off ration of ${\sim}10^9$ operated as an n-type enhancement mode with saturation mobility with $15.8\;cm^2/Vs$. In conclusion, the fabrication and characterization of thin-film transistors using amorphous indium tin zinc oxides for an active layer were reported. The devices were fabricated at room temperature by RF magnetron sputtering. The operation of the devices was an n-type enhancement mode with good saturation characteristics.