• Environmental Engineering Research
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• v.19 no.4
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• pp.339-344
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• 2014

Different types of polyethersulfone (PES) support layer for a thin film composite (TFC) membrane were synthesized under various synthesis conditions using the phase inversion method to study the combined effects of substrate, adhesive, and pore former. The permeability, selectivity, pore structure, and morphology of the prepared membranes were analyzed to evaluate the membrane performance. The combined use of substrate, adhesive, and pore former produced a thinner dense top layer, with more straight finger-like pores. The pure water permeation (PWP) of the optimized PES membrane was $27.42L/m^2hr$ (LMH), whereas that of bare PES membrane was 3.24 LMH. Moreover, membrane selectivity, represented as divalent ion ($CaSO_4$) rejection, was not sacrificed under the synthesis conditions, which produced the dramatically enhanced PWP. The high permeability and selectivity of the PES membrane produced under the optimized synthesis conditions suggest that it can be utilized as a potential support layer for TFC membranes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.4
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• pp.322-327
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• 2006

CdS films have been prepared on polycarbonate, polyethylene terephthalate, and Coming 7059 substrates by r.f magnetron sputtering technique at room temperature. A comparison of the properties of the films deposited on polymer and glass substrates was performed. In addition, the influence of the sputter power on the structural and optical properties of these films was evaluated. The XRD measurements revealed that CdS films were polycrystalline and retained the mixed structure of hexagonal wurtzite and cubic phase, regardless of substrate types. As the sputter power was increased from 75 to 150 Watt, the structure of CdS films was converted from the mixed of hexagonal and cubic phase to hexagonal phase. The morphology of CdS films is found to be continuous and dense. Also, the grain of CdS films is larger with increasing the sputter power. The average transmittance exceeded 80 % in the visible spectrum for all films and decreases slightly with the sputter power.

• Korean Journal of Materials Research
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• v.14 no.10
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• pp.737-742
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• 2004

$CuInSe_2$ (CIS) nanoparticles of chalcopyrite structure were directly synthesized by a solvothemal method in an autoclave with diethylamine as a solvent. A morphology change of the nanoparticles was observed as a function of reaction temperatures and times. Dense rod-type CIS nanoparticles with width of $5\sim10mm$ and length in the range of 30-80 nm were obtained at $180^{\circ}C$ for 36 hrs whereas spherical particles with diameter in the range of 5-10 nm were observed at $250^{\circ}C$ for 36 hrs. The formation of the rod-like nanoparticles in diethylamine, without double N-chelation, was explained by the Solution-Liquid-Solid (SLS) mechanism.

• Journal of the Korean Ceramic Society
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• v.47 no.6
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• pp.509-514
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• 2010

Porous mullite-bonded SiC (MBSC) ceramics were fabricated at temperatures ranging from 1400 to $1500^{\circ}C$ for 2 h using silicon carbide (SiC), alumina ($Al_2O_3$), strontium oxide (SrO), and poly (methyl methacrylate-coethylene glycol dimethacrylate) (PMMA) microbeads. The effect of template content on porosity, pore morphology, and flexural strength were investigated. The porosity increased with increasing the template content at the same sintering temperature. The flexural strength showed maximum after sintering at $1450^{\circ}C$/2 h for all specimens due to small pores and dense strut. By controlling the template content and sintering temperature, it was possible to produce porous MBSC ceramics with porosities ranging from 30% to 54%. A maximum flexural strength of ~51MPa was obtained at 30% porosity when no template were used and specimens sintered at $1450^{\circ}C$/2 h.

• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.406-410
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• 2020

Despite a simple preparation of manganese oxide (MnO₂) nanowires by electrodeposition, the improvement in specific capacitance (C_sp) and voltammetric response of the MnO₂ nanowire-based electrodes has been quite limited. This is attributed to the poor electrical conductivity of MnO₂ and its dense bulk morphology due to the aggregation of the nanowires. This study investigated the capacitive performance of MnO₂ nanowires electrodeposited on agarose thin films. The good ionic conductivity and porous network of the agarose film provided favorable growth conditions for the MnO₂ nanowires with suppressed aggregation. A maximum C_sp value of 686 F/g measured at a scan rate of 10 mV/s was obtained, which was significantly larger than that of 314 F/g for the agarose-free MnO₂ electrode at the same scan rate. The rate capability was also improved. The C_sp measured at a high scan rate of 100 mV/s retained 74.0% of the value measured at 10 mV/s, superior to the retention of 71.1% for the agarose-free MnO₂ electrode.

• ALGAE
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• v.23 no.2
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• pp.115-118
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• 2008

Cells of the dinoflagellate Peridinium were frequently observed in water samples of Togyo reservoir, and some species were responsible for dense blooms. Recently, we could identify them as P. bipes f. occultatum Lindem. and P. aciculiferum Lemm., considering morphology (Ki et al. 2005a; Ki and Han 2005b): However, some unidentified Peridinium cells with different shapes and body sizes were found among the samples collected during early spring. Here we describe their morphological characteristics such as thecal plate and body size to characterize its taxonomic identity by morphological characters. The formula of epithecal plates was recorded as 4 apical, 2 intercalary and 7 precingular plates (i.e. 4’', 2a, 7’'’') and the epicone in an apical view was symmetric. An apical pore was easy to make out under a light microscope. No cingular displacement was observed. The average body size was 33 $\mu$m in length with a range of 26-36 $\mu$m, and average 26 $\mu$m in width with a range of 21-31 $\mu$m, respectively; the cell was, therefore, shown slightly elongated. This way we identified Peridinium umbonatum Stein, 1883 for the first time from Korean freshwaters.

• Progress in Superconductivity
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• v.7 no.1
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• pp.52-57
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• 2005

[ $YBa_{2}Cu_{3}O_y$ ] superconducting films were prepared on $LaAlO_3$(100) single crystal substrate by spray pyrolysis method. The precursor solution was prepared by dissolving nitrate powders in de-ionized water. Both of ultrasonic and concentric nebulizers were used in order to generate fine droplets of precursor solution. C-axis oriented films were obtained at deposition temperature of $750\~850^{\circ}C$ and working pressure of 100 Torr and 500 Torr. In case of ultrasonic nebulizer, films showed rough and porous surface morphology due to formation of enormous droplets, while smooth and dense films were obtained for concentric nebulizer. A transport $J_c$ value of $0.43\;MA/cm^2$ at 77 K and self field was achieved on $LaAlO_3$(100) single crystal substrate.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.118-118
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• 1999

CVD방법에 의한 TiN 박막 형성에 있어서 ICP-CVD 방법이 대두되고 있다. 이것은 precursor에 대한 radical 형성, 식각된 패턴에서 양 벽의 self-shadowing 효과, 낮은 tress등으로 dense 한 박막을 얻을 수 있기 때문이다. TiN 박막은 Si 기판의 온도를 상온에서 50$0^{\circ}C$까지 유지하면서 TEMAT의 유량을 5-20sccm으로 변화시키면서 증착하였다. 증착 후 TiN 박막의 결정화에 따른 열처리는 Ar과 N2-가스분위기에서 in-situ로 증착하였다. 증착 후 TiN 박막증착 조건수립에 따른 플라즈마 특성진단은 전자의 온도와 밀도, 평균 전자밀도, 이온 에너지 분포, radical 분포, negative 이온분포 등으로 측정하였다. 플라즈마 변수에 따른 TiN 박막의 결정성과 상 변화는 XRD로 분석하였고, 조성비 및 TiN 박막의 원소화학적 상태, 결합에너지, 각 상에 따른 결합 에너지 천이정도, 초기 형성과정 및 반응기구 등은 RBS와 XPS로 조사하였다. TiN 박막의 표면상태, morphology 거칠기, TiN/Si(100)구조에서 계면상태 등은 SEM, AFM, 그리고 HRTEM으로 분석하였다. TiN 구조 박막의 비저항, carrier concentration 그리고 mobility 측정은 박막의 표면이 균일하고 bls-홀이 없는 것으로 하여 4-point probe 방법으로 측정하였다. 이들 분석으로부터 ICP-CVD 방법에 의하여 형성된 TiN 박막이 초고집적 반도체 소자의 contact barrier layer로서의 적용 가능성을 평가하였다.

• Journal of The Korean Astronomical Society
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• v.41 no.5
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• pp.139-145
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• 2008

The molecular cloud, embedding AFGL 2591, has a "head-and-tail" structure with a total mass of ${\sim}\;1800\;M_{\odot}$, about half of the mass (${\sim}\;900\;M_{\odot}$) in the head (size ${\sim}\;1.2\;pc$ in diameter), and another half in the envelope (${\sim}\;3.5\;pc$ in the east-west direction). We found a new cloud in the direction toward north-east from AFGL 2591 (projected distance ${\sim}\;2.4\;pc$), which is probably associated with the AFGL 2591 cloud. The $^{12}CO$ spectrum clearly shows a blue-shifted high-velocity wing at around the velocity $-20\;{\sim}\;-10\;km\;s^{-1}$, but it is not clear whether this high-velocity component has a bipolar nature in our observations. The observed CN spectra also show blue-shifted wing component but the existence of the red-shifted component is not clear, either. In some CN and HCN spectra, the highvelocity components appear as a different velocity component, not a broad line-wing component. The dense cores, traced by CN and HCN, exist in the 'head' of the AFGL 2591 cloud with an elongated morphology roughly in the north-south direction with a size of about 0.5 pc. The abundance ratio between CN and HCN is found to be about 2 - 3 within the observed region, which may suggest a possibility that this core is being affected by the embedded YSOs or by possible shocks from outside.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1437-1439
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• 1996

In this paper, investigations on a three stage processing technique involving the co-evaporation of In-Se, Cu-Se and In-Se in this order at different deposition condition was undertaken. At first stage, we obtained good $In_{2}Se_{3}$ films by In-Se coevaporation. $In_{2}Se_{3}$ films show smooth and dense structure. And ration of In:Se was 2:3 $CulnSe_2$ thin films deposited by three stage process have shown strong adhesion on Mo coated glass substrates and good morphological properties suitable device fabrication. XWD spectra show single phase chalcopyrite $CulnSe_2$ films with strong orientation in the 112 plane. Resistivity of $CulnSe_2$ thin films was about $5{\times}10^{5}\;{\Omega}{\cdot}cm$. Surface morphology of CdS/$CulnSe_2$/Mo films was very good because of no pin holes.