• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.3
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• pp.59-65
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• 1999

In this paper, we had studied the possibility of application as Cu thin films from (hfac)Cu(VTMOS) which is very stable. Cu thin films had been studied as a function of deposition temperature. Substrates used in the experiment were PVD TiN on Si wafer. Deposition conditions were as follow : deposition temperature $50^{\circ}C$. Cu thin films were analyzed by AES, four point probe, XRD and SEM. All of deposited films were very pure and some favoring of <111> planes perpendicular to the substrate surface were observed. Cu thin films had two distinct growth rates at various deposition temperature. One is the surface reaction limited region below $200^{\circ}C$, and the other is the mass transport limited region above $200^{\circ}C$. The resistivity of deposited Cu thin films under the optimum deposition condition is $2.5mu\Omega.cm$ Thus, properties of deposited Cu thin films using (hfac)Cu(VTMOS) didn't show difference with Cu thin films from other precursors.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.317-319
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• 2017

We propose a cosmological survey to probe star formation and nuclear activity in galaxies at redshifts of z=2-4 by polycyclic aromatic hydrocarbon (PAH) features using the SPICA mid-infrared instrument (SMI) with a spectral resolution of R=20. We will cover a wavelength range of $20-36{\mu}$ that corresponds to z=2-4 for the PAH features (11.3, 7.7, and $6.2{\mu}$). The sensitivity will be $1{\times}10^{-19}W/m^2(5{\sigma})$ in case of a reference survey that covers 4 arcmin2 field in a one-hour observation. It corresponds to $L_{IR}=2{\times}10^{11}L_{\odot}$ at z=3 and will give us more than 10000 galaxies in a 450 hour survey.

• Journal of Embryo Transfer
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• v.22 no.3
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• pp.173-178
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• 2007

돼지 정자의 성 선별에는 일반적으로 유속 세포 분석기를 이용한다. 유속 세포 분석은 DNA량의 차이에 기초하여 정자를 분리하는 기술로써 X 정자와 Y 정자를 90% 정확도로 분리할 수 있다. 그러나 이러한 유속 세포분석 기술은 정자의 손상을 야기해 정자의 기능과 수정능에 영향을 미치므로, 본 연구에서는 특정한 핵산 서열을 탐지할 수 있는 Chromogenic in situ hybridization(CISH)을 그와 비교하여 평가하였다. 유속 세포 분석을 수행하기 위해 정자를 SYBR 14와 PI로 염색하였고, histogram, dotplot, density, contour를 측정하였다. Y 염색체 특이적인 primer를 이용한 PCR로 유속 세포 분석의 정확도를 검사하였다. HRP/DAB 시스템에 기초한 CISH 분석에는 X 또는 Y 염색체에 상보적으로 결합하는 probe가 사용되었다. CISH 분석은 기존의 방법들보다 빠르고 쉬우며 비용이 적게 든다는 장점이 있다. 또한, CISH는 보다 정화한 정자의 선별을 가능하게 하는 것으로 나타났다. 본 연구에 따르면 CISH가 기존의 선별 방법들을 평가하는 기술로서만이 아니라 특정한 성별을 가진 포유동물의 생산에도 사용될 수 있을 것이다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.369-373
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• 2005

To investigate the mechanism of ballast-flying phenomena by strong wind induced by high-speed trains, wind velocity in the vicinity of the track has been measured using 16-channel Kiel-probe array and detailed flow structure near the surface of the track has been analyzed. The position at which the underflow fully develop has been examined in order to assess the driving force of the turbulent flow under train and the results yields that the turbulent flow owing to the cavity of the inter-car as well as the friction force at the underbody of the train is the main reason of the strong wind under high-speed train. The preceding wind tunnel test results has been introduced to assess the probability of ballast-flying during the passage of the high-speed train by comparing the results from field-measuring. The results shows that when the G7 train as well as the KTX train runs at 300km/h, about 25m/s wind gust is induced just above the tie and the probability for small ballast under 50g to fly is about 50% when it is on the tie. If the G7 train runs at 350km/h, the wind gust just above the tie increases to 30m/s, therefore more radical countermeasure seems to be needed.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.3124-3124
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• 2001

The development and evolution of near infra-red spectroscopic (NIS) calibrations for high-moisture materials is an expensive proposition. Such investment is suspect unless the instrument, or instruments, on which calibrations were developed can be preserved intact or re-standardized as component replacements occurs. The objective of this paper is to detail the changes in performance of a six-year old instrument after maintenance in years five and six resulted in collection of spectral data that was increasingly removed from the calibration population. Calibrations for the analysis of mature sugarcane stalks, a high-moisture material, were developed successfully in 1995 using a broad sample population in terms of genetics, and spectral and temporal variation. The spectral library was further broadened in 1996. In 1997, 1999, 1999, and 2000, additional samples constituting 10% of the laboratories throughput were subjected to full component analyses using routine laboratory techniques. These samples were primarily random samples, but were complemented with samples that were significant for the spectral H statistic or for the component t statistic. In 1998, an additional calibration was developed for populations consisting of samples of either mature stalks (culms) or sucker culms. Substantial additional samples numbers were collected for this calibration in 1999 and 2000. Attempts to standardize the scanning spectrophotometer used for these calibrations with a second similar instrument in 1999 failed because the instruments were optically different, and standardization could not account for this. Maintenance adjustments were made to the remote reflectance probe of the original instrument in 1999, and replacement of its PbS detectors was done in 2000. Spectral data collected in 1999 and 2000 yielded spectral populations that were increasingly removed from the respective spectral populations on which the calibrations were developed. The mature stalk calibrations benefited marginally from evolutionary calib.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.261-261
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• 1994

Bovine milk xanthine oxidase (E.C.1.1.3.22, XO) purchased from Sigma Chemical Co. had the three protein fragments below 150 kDa on 7.5％ SDS-PAGE, which did not show enzyme activity. To remove these fragments, the enzyme preparation was further purified through Sephadex G-200 column chromatography. Two peaks exhibiting enzymatic activity were separated very closely to the void volume, which were revealed as two different enzyme forms, dimeric and monomeric, confirmed by activity staining on native PAGE. Anti sera-against each of the two enzyme forms were raised by subcutaneous injection at multiple sites on the back of rabbits during 4 weeks. On the immunodiffusion test, it was found that both of the antisera of the two forms could react with each other, which implied that their epitopes were identical In the Western blot analysis of mouse liver cytosol fraction, it was found that rabbit anti-XO antibody bound well with the protein band of monomeric mouse liver XO of about 150kDa. Based on this result, mouse liver cDNA 1 ibrary was screened by in situ hybridizat ion wi th rabbi t anti -XO antibody as probe. Through the immunological screening, recombinant phages giving positive signal by the production of XO were selected and further purified. To validate these clones, purified phages were lysogenized in E. coli Y1089 and their lysates were analysed for enzyme activity and immunoreactivity, It was verified that lysates of the purified recombinant phage lysogens exhibited the enzymatic activity as well as bound wi th XO antibody, when induced by IPTG. The above results assert that selected recombinant phage carries mouse liver XO gene.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.3
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• pp.133-138
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• 2017

We evaluated the structural, electrical and optical properties of tungsten (W)-doped $Ge_8Sb_2Te_{11}$ thin films. In a previous work, GeSbTe alloys were doped with different materials in an attempt to improve thermal stability. 200 mm thick $Ge_8Sb_2Te_{11}$ and W-doped $Ge_8Sb_2Te_{11}$ films were deposited on p-type Si (100) and glass substrates using a magnetron co-sputtering system at room temperature. The fabricated films were annealed in a furnace in the $0{\sim}400^{\circ}C$ temperature range. The structural properties were analyzed using X-ray diffraction (X'pert PRO, Phillips). The results showed increased crystallization temperature ($T_c$) leading to thermal stability in the amorphous state. The optical properties were analyzed using an UV-Vis-IR spectrophotometer (Shimadzu, U-3501, range : 300~3,000 nm). The results showed an increase in the crystalline material optical energy band gap ($E_{op}$) and an increase in the $E_{op}$ difference (${\Delta}E_{op}$). This is a good effect to reduce memory device noise. The electrical properties were analyzed using a 4-point probe (CNT-series). This showed increased sheet resistance ($R_s$), which reduces programming current in the memory device.

• Biomaterials and Biomechanics in Bioengineering
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• v.3 no.3
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• pp.129-140
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• 2016

This article reports the development of biodegradable photoluminescent polymer (BPLP)-based nanoparticles (NPs) incorporating either magnetic nanoparticles (BPLP-MNPs) or gadopentate dimeglumine (BPLP-Gd NPs), for cancer diagnosis and treatment. The aim of the study is to compare these nanoparticles in terms of their surface properties, fluorescence intensities, MR imaging capabilities, and in vitro characteristics to choose the most promising dual-imaging nanoprobe. Results indicate that BPLP-MNPs and BPLP-Gd NPs had a size of $195{\pm}43nm$ and $161{\pm}55nm$, respectively and showed good stability in DI water and 10% serum for 5 days. BPLP-Gd NPs showed similar fluorescence as the original BPLP materials under UV light, whereas BPLP-MNPs showed comparatively less fluorescence. VSM and MRI confirmed that the NPs retained their magnetic properties following encapsulation within BPLP. Further, in vitro studies using HPV-7 immortalized prostate epithelial cells and human dermal fibroblasts (HDFs) showed > 70% cell viability up to $100{\mu}g/ml$ NP concentration. Dose-dependent uptake of both types of NPs by PC3 and LNCaP prostate cancer cells was also observed. Thus, our results indicate that BPLP-Gd NPs would be more appropriate for use as a dual-imaging probe as the contrast agent does not mask the fluorescence of the polymer. Future studies would involve in vivo imaging following administration of BPLP-Gd NPs for biomedical applications including cancer detection.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2283-2287
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• 2007

Amyloid fibril formation of amyloid β/A4 protein (Aβ) is critical to understand the pathological mechanism of Alzheimer's disease and develop controlling strategy toward the neurodegenerative disease. For this purpose, dequalinium (DQ) has been employed as a specific modifier for Aβ aggregation and its subsequent cytotoxicity. In the presence of DQ, the final thioflavin-T binding fluorescence of Aβ aggregates decreased significantly. It was the altered morphology of Aβ aggregates in a form of the bundles of the fibrils, distinctive from normal single-stranded amyloid fibrils, and the resulting reduced β-sheet content that were responsible for the decreased fluorescence. The morphological transition of Aβ aggregates assessed with atomic force microscope indicated that the bundle structure observed with DQ appeared to be resulted from the initial multimeric seed structure rather than lateral association of preformed single-stranded fibrils. Investigation of the seeding effect of the DQ-induced Aβ aggregates clearly demonstrated that the seed structure has determined the final morphology of Aβ aggregates as well as the aggregative kinetics by shortening the lag phase. In addition, the cytotoxicity was also varied depending on the final morphology of the aggregates. Taken together, DQ has been considered to be a useful chemical probe to control the cytotoxicity of the amyloid fibrils by influencing the seed structures which turned out to be central to develop therapeutic strategy by inducing the amyloid fibrils in different shapes with varied toxicities.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.393-399
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• 2004

Useful genes can be Screened from various environments by construction of metagenomic DNA libraries. In this study, water samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities. The crude DNAs r were extracted by the SDS-based freezing-thawing method, and then further purified using an $UltraClean^{TM}$ kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoR I, BamH I, and Sac II in Escherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13-15 kb in size. The bphC genes responsible for degradation of aromatic hydrocarbons via mets-cleavage were identified from the metagenomic libraries by colony hybridization using the bphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2, 3-DHBP) dioxygenase gene (bphC ), capable of degradation of 2,3-DHBP, was cloned and its nucleotide Sequences analyzed. The genes consisted of 966 and 897 base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed to 2,3-DHBP and Showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results in-dicated that the bphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation of aromatic pollutants.