• Bulletin of the Korean Chemical Society
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• v.21 no.6
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• pp.583-587
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• 2000

Depletion kinetics of ground state FeO molecules by $0_2$, $N_2O$ and $N_2$ has been studied at room temperature. The ground state FeO molecules were generated by photolysis of a $Fe$(CO)_5$/M(O_2$, $N_2O)/He$ mixture using an unfocused weak UV laser beam. The formation of ground state FeO molecules was identified by a laser-induced fluorescence (LIF) method. The intensity distribution of those undisturbed rotational lines suggests that the rotational temperature of the ground state FeO molecules is lower than room temperature. The LIF intensities of FeO molecules at different partial pressures of $0_2$, $N_2O$ and $N_2$ were monitored as a function of the time delay between the photolysis and probe laser pulses to obtain the depletion rate constants for the ground state FeO. They were 1.7+ 0.2x $10^{-12}$, 4.8 $\pm0.4$ x $10^{-12}$, and $1.4\pm$ 0.2x $10^{-12}cm^3$molecule^{-1}s^{-1}$$ by $0_2$, $N_20$, and $N_2$, respectively.

• Journal of the Korean Vacuum Society
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• v.16 no.2
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• pp.145-152
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• 2007

The evolution dynamics of nanoscale Ge islands on both Si (001) and (113) surfaces is explored using ultraviolet photoelectron emission microscopy (UV-PEEM). Real-time monitoring of the in-situ growth of the Ge island structures can allow us to study the variation of the size, the shape and the density of the nanostructures. For Ge depositions greater than ${\sim}4$ monolayer (ML) with a growth rate of ${\sim}0.4\;ML/min$ at temperatures of $450-550^{\circ}C$, we observed island nucleation on both surfaces indicating the transition from strained layer to island structure. During continuous deposition the circular islands grew larger via ripening processes. AFM measurements showed that the islands grown on Si (001) were dome-shaped while the islands on Si (113) were multiple-side faceted with flat tops of (113)-orientation. In contrast, for Ge deposition with a lower growth rate of ${\sim}0.15\;ML/min$ on Si(113), we observed the shape transition from circular into elongated island structures. The elongated islands grew longer along the [$33\bar{2}$] during continuous Ge deposition. The shape evolution of the islands is discussed in terms of strain relaxation and kinetic effects.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.393-393
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• 2012

Optically active nanostructures such as subwavelength moth-eye antireflective structures or surface enhanced Raman spectroscopy (SERS) active structures have been demonstrated to provide the effective suppression of unwanted reflections as in subwavelength structure (SWS) or effective enhancement of selective signals as in SERS. While various nanopatterning techniques such as photolithography, electron-beam lithography, wafer level nanoimprinting lithography, and interference lithography can be employed to fabricate these nanostructures, roll-to-roll (R2R) nanoimprinting is gaining interests due to its low cost, continuous, and scalable process. R2R nanoimprinting requires a master to produce a stamp that can be wrapped around a quartz roller for repeated nanoimprinting process. Among many possibilities, two different types of mask can be employed to fabricate optically active nanostructures. One is self-assembled Au nanoparticles on Si substrate by depositing Au film with sputtering followed by annealing process. The other is monolayer silica particles dissolved in ethanol spread on the wafer by spin-coating method. The process is optimized by considering the density of Au and silica nano particles, depth and shape of the patterns. The depth of the pattern can be controlled with dry etch process using reactive ion etching (RIE) with the mixture of SF6 and CHF3. The resultant nanostructures are characterized for their reflectance using UV-Vis-NIR spectrophotometer (Agilent technology, Cary 5000) and for surface morphology using scanning electron microscope (SEM, JEOL JSM-7100F). Once optimized, these optically active nanostructures can be used to replicate with roll-to-roll process or soft lithography for various applications including displays, solar cells, and biosensors.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.573-574
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• 2013

본 연구에서는 Roll-to-Roll 스퍼터를 이용한 ITO 성막 공정에서 Ar 이온 빔 처리가 플렉시블 ITO 박막의 전기적, 광학적, 구조적 특성에 미치는 효과를 연구하였다. Roll-to-Roll 스퍼터를 이용하여 ITO 박막을 성막할 때 Linear ion source를 이용하여 Ar 이온을 ITO 박막에 직접 조사할 때 일어나는 ITO 박막의 변화를 분석하였다. Ar 이온 빔에 인가되는 DC 파워 변화에 따른 ITO 박막의 전기적, 광학적 특성 변화를 Hall measurement 및 UV/Visible spectrometry 분석법을 통해 확인하였다. 이온 빔 처리 공정 시 인가되는 파워가 DC 100 W일 때 $5.81{\times}10^{-4}{\Omega}-cm$으로 이온 빔 처리를 하지 않은 $1.14{\times}10^{-3}{\Omega}-cm$에 보다 낮은 비저항을 나타냄을 확인할 수 있었다. 이온 빔 처리 전/후 ITO 박막의 결정성은 포항 가속기 X-ray scattering법을 이용하여 분석하였으며, 결과를 통해 Ar 이온 빔 처리가 ITO 박막의 표면에서의 국부적인 결정성을 향상을 일으킴을 알 수 있었다. 이러한 결정성 향상이 Roll-to-Roll 스퍼터된 ITO 박막의 전기적 특성을 향상과 매우 밀접한 관계가 있음을 확인할 수 있었다. 또한 이온 빔 처리 전/후 ITO/CPI의 기판 휨에 따른 기계적 안정성을 알아보기 위해 bending frequency 60 Hz, bending radius 15mm로 bending test를 진행을 통하여 이온 빔 처리 전후 ITO 박막의 특성을 비교 확인하였다. 본 실험 결과를 통해 Ar 이온빔 조사에 의해 상온에서 결정형 ITO 박막을 CPI 기판위에 형성 할 수 있었다. 또한 최적화된 ITO 박막을 이용하여 유기 태양전지를 제작하였으며 이를 통해 Ar 이온빔 처리된 결정형 ITO의 유연 태양전지 응용 가능성을 타진하였다.

• Advances in nano research
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• v.5 no.3
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• pp.193-201
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• 2017

ZnO, ZnO: Cu, Ga, and ZnO: Cu, Ga, Ag thin films were obtained by oxidization of ZnS and ZnS: Cu, Ga films deposited onto glass substrates by electron-beam evaporation from ZnS and ZnS: Cu, Ga targets and from ZnS: Cu, Ga film additionally doped with Ag by the closed space sublimation technique at atmospheric pressure. The film thickness was about $1{\mu}m$. The oxidation was carried out at $600-650^{\circ}C$ in air or in an atmosphere containing water vapor. Structural characteristics were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). Photoluminescence (PL) spectra of the films were measured at 30-300 K using the excitation wavelengths of 337, 405 and 457.9 nm. As-deposited ZnS and ZnS: Cu, Ga films had cubic structure. The oxidation of the doped films in air or in water vapors led to complete ZnO phase transition. XRD and AFM studies showed that the grain sizes of oxidized films at wet annealing were larger than of the films after dry annealing. As-deposited doped and undoped ZnS thin films did not emit PL. Shape and intensity of the PL emission depended on doping and oxidation conditions. Emission intensity of the films annealed in water vapors was higher than of the films annealed in the air. PL of ZnO: Cu, Ga films excited by 337 nm wavelength exhibits UV (380 nm) and green emission (500 nm). PL spectra at 300 and 30 K excited by 457.9 and 405 nm wavelengths consisted of two bands - the green band at 500 nm and the red band at 650 nm. Location and intensities ratio depended on the preparation conditions.

• Microbiology and Biotechnology Letters
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• v.11 no.1
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• pp.39-45
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• 1983

One of Streptomyces sp. was screened as an antibiotic producing strain against Gram positive bacteria specifically from about one hundred Actinomycetes collections. The isolated KM-48 strain, indexed in our collection, was secreted an anbitiotic in nutrient broth culture. The active principle was extracted with acetone from the lyophilized solid of cultured filtrate. The nonadsorbed elute in aluminium oxide was isolated as a purified homogeneity which revealed a sing1e spot under ultra-violet beam on avicel thin layer chromatography. The isolated antibiotic was sensitive specifically against the Gram positive bacteria and fungi. About fifty percent inhibition of the control growth on Bacillus amyloliquefaciens was 18$\mu\textrm{g}$/$m\ell$. The antibiotic was lavile against thermotreatment and stabled in acidic condition remarkably. The KM-48 was identified as a similar strain to Streptomyces tsusimaensis on its morphological and cultural characteristics.

• Macromolecular Research
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• v.15 no.4
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• pp.348-356
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• 2007

The aim of this study was to fabricate a submicro-and micro-patterned fibronectin coated wafer for a cell culture, which allows the positions and dimensions of the attached cells to be controlled. A replica molding was made into silicon via a photomask in quartz, using E-beam lithography, and then fabricated a polydimethylsiloxane stamp using the designed silicon mold. Hexadecanethiol $[HS(CH_2){_{15}}CH_3]$, adsorbed on the raised plateau of the surface of polydimethylsiloxane stamp, was contact-printed to form self-assembled monolayers (SAMs) of hexadecanethiolate on the surface of an Au-coated glass wafer. In order to form another SAM for control of the surface wafer properties, a hydrophilic hexa (ethylene glycol) terminated alkanethiol $[HS(CH_2){_{11}}(OCH_2CH_2){_6}OH]$ was also synthesized. The structural changes were confirmed using UV and $^1H-NMR$ spectroscopies. A SAM terminated in the hexa(ethylene glycol) groups was subsequently formed on the bare gold remaining on the surface of the Aucoated glass wafer. In order to aid the attachment of cells, fibronectin was adsorbed onto the resulting wafer, with the pattern formed on the gold-coated wafer confirmed using immunofluorescence staining against fibronectin. Fibronectin was adsorbed only onto the SAMs terminated in the methyl groups of the substrate. The hexa (ethylene glycol)-terminated regions resisted the adsorption of protein. Human dermal fibroblasts (P=4), obtained from newborn foreskin, only attached to the fibronectin-coated, methyl-terminated hydrophobic regions of the patterned SAMs. N-HDFs were more actively adhered, and spread in a pattern spacing below $14{\mu}m$, rather than above $17{\mu}m$, could easily migrate on the substrate containing spacing of $10{\mu}m$ or less between the strip lines.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.26 no.1
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• pp.43-58
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• 1998

The Kwinana Shoreline Fumigation Experiment (KSFE) took place at Fremantle, WA, Australia between January 23 and February 8, 1995. The CSIRO DAR LIDAR measured plume sections from near the Kwinana Power Station (KPS) stacks to up to about 5 km downstream. It also measured boundary layer aerosols and the structure of the boundary layer on some occasions. Both stages A and C of KPS were used as tracers at different times. The heart of the LIDAR system is a Neodymium-doped Yttrium-aluminum-garnet (Nd:YAG) laser operating at a fundamental wavelength of 1064 nm, with harmonics of 532 nm and 355 nm. For these experiments the third harmonic was used because the UV wavelength at 355 nm is eye safe beyond about 50 m. The laser fires a pulse of light 6 ns in duration (about 1.8 m long) and with an energy (at the third harmonic) of about 70 mJ. This pulse subsequently scattered and absorbed by both air molecules and particles in the atmosphere. A small fraction of the laser beam is scattered back to the LIDAR, collected by a telescope and detected by a photo-multiplier tube. The intensity of the signal as a function of time is a measure of the particle concentration as a function of distance along the line of the laser shot. The smoke plume was clearly identifiable in the scans both before and after fumigation in the thermal internal boundary layer (TIBL). Both power station plumes were detected. Over the 9 days of operation, 1,568 plumes scans (214 series) were performed. Essentially all of these will provide instantaneous plume heights and widths, and there are many periods of continuous operation over several hours when it should be possible to compile hourly average plume statistics as well. The results of four days LIDAR observations of the dispersion of smoke plume in the TIBL at a coastal site are presented for the case of stages A and C.

• Journal of Embryo Transfer
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• v.27 no.1
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• pp.37-43
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• 2012

This study evaluated a method of sorting X and Y chromosomes based on size using the forward angle light scatter related refractive index (FSC) of a flow cytometer. Hanwoo bulls sperm were separated to X and Y chromosomes by the parameters of FSC or Hoechst 33342 intensity. As a result, using monitor program linked flow cytometry during sorting processing, the purities were $97{\pm}0.57$ or $96{\pm}0.67%$ for the X-fraction and $96{\pm}0.33$ or $97{\pm}1.33%$ for the Y-fraction in the two sperm sorting methods. There were no differences in the X and Y ratios (X and Y %) between the sperm sorting methods based on FSC or DNA content. The proportions of female and male embryos used for in vitro fertilization and development were $66.03{\pm}3.31$ or $69.37{\pm}1.41%$, and $70.56{\pm}2.42$ or $56.11{\pm}3.09%$ when sperm were processed using the sex sorting method by FSC or Hoechst 33342. In conclusion, further study is needed to determine the optimum procedure and improve the nozzle to enhancing sorting accuracy or efficiency. Also, the findings of this study do not negate the possibility that the difference method of sperm sorting cannot use a UV laser beam.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.99-101
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• 1998

1. Introduction : The conventional grafting polymerization technique requires chemically reactive groups on the surface as well as on the polymer chains. For this reason, a series of prefunctionalization steps are necessary for covalent grafting. The surface prefunctionalizational technique for grafting can be used to ionization radiation, UV, plasma, ion beam or chemical initiators. Of these techniques, radiation method is one of the useful methods because of uniform and rapid creation of active radical sites without catalytic contamination in grafted samples. If the diffusion of monomer into polymer is large enough to come to the inside of polymer substrate, a homogeneous and uniform grafting reaction can be carried out throughout the whole polymer substrate. Radiation-induced grafting method may attach specific functional moieties to a polymeric substrate, such as preirradiation and simultaneous irradiation. The former is irradiated at backbone polymer in vacuum or nitrogen gas and air, and then subsequent monomer grafting by trapped or peroxy radicals, while the latter is irradiated at backbone polymer in the presence of the monomer. Therefore, radiation-induced polymerization can be used to modification of the chemical and physical properties of the polymeric materials and has attracted considerable interest because it imparts desirable properties such as blood compatibility. membrane quality, ion excahnge, dyeability, protein adsorption, and immobilization of bioactive materials. Synthesizing biocompatible materials by radiation method such as preirradiation or simultaneous irradiation has often used $\gamma$-rays to graft hydrophilic monomers onto hydrophobic polymer substrates. In this work, in attempt to produce surfaces that show low levels of anti-fouling of bovine serum albumin(BSA) solutions, hydroxyethyl methacrylate(HEMA) was grafted polypropylene membrane surfaces by preirradiation technique. The anti-fouling effect of the polypropylene membrane after grafting was examined by permeation BSA solution.