• The Korean Journal of Mycology
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• v.24 no.2 s.77
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• pp.89-92
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• 1996

This study were carried out to evaluate the effect of quantities of substrate on the yields for 2 years $(1993{\sim}1994)$. The substrates are cotton waste, rice straw and rice hull. It were revealed that cotton waste mixed rice straw was the best yield of fruit body. It gave more increased $(10{\sim}22%)$ than other substrates $(7{\sim}15%)$ when increasing the quantities of substrate. And cotton waste mixed with rice hull was most fast for first pinhead formation.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.2
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• pp.25-34
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• 1994

In this research, investigations were made on the effect of type and load of organic substrate on phosphorus release. Reactors of three different sizes were operated, being fed on five kinds of organic substrates. The quantitative analyses were made on phosphorus release and substrate utilization under anaerobic condition. The molar ratios of the uptaken organic substrate to the released phosphorus were 0.5 with acetate, 0.6 with glucose, 0.8 with glucose/acetate, and 1.2 with glucose/acids, respectively. The phosphorus release was inhibited at the higher organic load than the normal at stead state. Both acetate and acids/glucose enhanced phosphorus release- as well as uptake-rate, however, the complete phosphorus removal was achieved after the microbial adaptation to the new environment. In case with acetate, operation was hampered by the poor sludge settleability and phosphorus uptake was not enough although the phosphorus release was active. But with milk/starch, the phosphorus release and uptake was well developed even though phosphorus release was not comparatively high. From this study, it was concluded that organic substrates, such as glucose seemed to be converted fatty acids after fast bio-sorption, followed by concurrent uptake of these acids by excess phosphorus removing bacteria.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.36-37
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• 2006

Both negative and positive substrate bias effects on the structural properties and field-emission characteristics are investigated. carbon nanotubes (CNTs) are grown on Ni catalysts employing an inductively-coupled plasma chemical vapor deposition (ICP-CVD) method. Characterization using various techniques, such as field-emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Auger spectroscopy (AES), and Raman spectroscopy, shows that the physical dimension as well as the crystal quality of CNTs grown can be changed and controlled by the application of substrate bias during CNT growth. It is for the first time observed that the prevailing growth mechanism of CNTs, which is either due to tip-driven growth or based-on-catalyst growth, may be influenced by substrate biasing. It is also seen that negative biasing would be more effectively role in the vertical-alignment of CNTs compared to positive biasing. However, the CNTs grown under the positively bias condition display much better electron emission capabilities than those grown under negative bias or without bias. The reasons for all the measured data regarding the structural properties of CNTs are discussed to confirm the correlation with the observed field-emissive properties.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.190-197
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• 1996

The optimal conditions and substrate specificity of whole body esterase (EST) activity, effects of inhibitors (Eserine, Paraoxon, p-HMB, DDVP, DFP) on the enzyme, and ontogenv of the isozymes were determined in Lucilio ilfustris Meisen. The optimal temperature was $45^{\circ}C$ regardless of kind of reacted substrate, $\alpha-naphthyl$ acetate $(\alpha-Nal,$ a.naphthvl butylate $(\alpha-N),$ and Pnaphthyl acetate $(\beta-Na),$ but the optimal pH showed some regioselectivitv to naphthvl group of the esters; PH 7.0 for Iform, pH 7.5 for a-form. The maximum reaction rate was recorded at about 2.5 $\times$ 10's M of PNa and etNa, but 1.0 $\times$ 10'S M of $\alpha-Nb.$ Among the five EST inhibitors tested, DDVP was the most powerful. However, distinction of the relative specificity of inhibitors between three body parts, head, thorax, and abdomen, was shouts, representing differences in the distribution and activity of isozvmes. Of 12 carboxyl-esterases (CE), 8 cholinesterases (ChE) and 2 arvlesterases (ArE) identified based on their inhibitor specificity throughout the development, two larval and prepupal stage specific ChEs, no pupal specific, and 2 CEs.2ChEs. and one ArE adult specific isozvmes were confirmed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.7
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• pp.738-746
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• 2004

Recently zinc oxide(ZnO) has emerged as one of the most promising transparent conducting films with a strong demand of low cost and high performance optoelectronic devices, ZnO film has many advantages such as high chemical and mechanical stabilities, and abundance in nature. In this paper, in order to obtain the excellent transparent conducting film with low resistivity and high optical transmittance for Plasma Display Pannel(PDP), aluminium doped zinc oxide films were deposited on Corning glass substrate by dc magnetron sputtering method. The effects of the discharge power and doping amounts of $Al_2$$O_3$ on the electrical and optical properties were investigated experimentally. Particularly in order to lower the electrical resistivity, positive and negative bias voltages were applied on the substrate, and the effect of bias voltage on the electrical properties of ZnO:Al thin film were also studied and discussed. Films with lowest resistivity of $4.3 \times 10 ^{-4} \Omega-cm$ and good transmittance of 91.46 % have been achieved for the films deposited at 1 mtorr, $400^{\circ}C$, 40 W, Al content of 2 wt% with a substrate bias of +30 V for about 800 nm in film thickness.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.1
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• pp.34-46
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• 2004

Copper films were prepared by using ECR-MOCVD(Electron Cyclotron Resonance Metal Organic Chemical Vapor Deposition) coupled with a DC bias system. The DC bias is connected to the electrode which placed 1∼3cm above the polymer substrate. The pulse electrical field around the electrode attracts the positive charged copper ions generated from the dissociation of copper precursor, $Cu(hfac)_2$, under ECR plasma. Condensation of supersaturated copper ions in the space between the electrode and substrate, makes it possible to deposit copper film on the polymer substrate even at room temperature. In this study, optimization of the electrode configuration was carried out in order to obtain the uniform films. The uniformity of the deposited films were closely related to the parameters of electrode geometry such as electrode shape, thickness, grid size and the spacing between electrodes. The most uniform copper film was observed with the electrode that enabled uniform electrical field distribution across the whole dimension of electrode.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.210-210
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• 2000

Vertically well aligned multi-wall carbon nanotubes (CNT) were grown on nickel coated glass substrates by plasma enhanced hot filament chemical vapor deposition at low temperatures below 600$^{\circ}C$. Acetylene and ammonia gas were used as the carbon source and a catalyst. Effects of growth parameters such as pre-treatment of substrate, plasma intensity, filament current, imput gas flow rate, gas composition, substrate temperature and different substrates on the growth characteristics of CNT were systematically investigated. Figure 1 shows SEM image of CNT grown on Ni coated glass substrate. Diameter of nanotube was 30 to 100nm depending on the growth condition. The diameter of CNT decreased and density of CNT increased as NH3 etching time etching time increased. Plasma intensity was found to be the most critical parameter to determine the growth of CNT. CNT was not grown at the plasma intensity lower than 500V. Growth of CNT without filament current was observed. Raman spectroscopy showed the C-C tangential stretching mode at 1592 cm1 as well as D line at 1366 cm-1. From the microanalysis using HRTEM, nickel cap was observed on the top of the grown CNT and very thin carbon amorphous layer of 5nm was found on the nickel cap. Current-voltage characteristics using STM showed about 34nA of current at the applied voltage of 1 volt. Electron emission from the vertically well aligned CNT was obtained using phosphor anode with onset electric field of 1.5C/um.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.51-51
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• 2010

Group III-nitride semiconductors have been widely studied as the materials for growth of light emitting devices. Currently, GaN devices are predominantly grown in the (0001) c-plane orientation. However, in case of using polar substrate, an important physical problem of nitride semiconductors with the wurtzite crystal structure is their spontaneous electrical polarization. An alternative method of reducing polarization effects is to grow on non-polar planes or semi-polar planes. However, non-polar and semipolar GaN grown onto r-plane and m-plane sapphire, respectively, basically have numerous defects density compared with c-plane GaN. The purpose of our work is to reduce these defects in non-polar and semi-polar GaN and to fabricate high efficiency LED on non/semi-polar substrate. Non-polar and semi-polar GaN layers were grown onto patterned sapphire substrates (PSS) and nano-porous GaN/sapphire substrates, respectively. Using PSS with the hemispherical patterns, we could achieve high luminous intensity. In case of semi-polar GaN, photo-enhanced electrochemical etching (PEC) was applied to make porous GaN substrates, and semi-polar GaN was grown onto nano-porous substrates. Our results showed the improvement of device characteristics as well as micro-structural and optical properties of non-polar and semi-polar GaN. Patterning and nano-porous etching technologies will be promising for the fabrication of high efficiency non-polar and semi-polar InGaN LED on sapphire substrate.

• Journal of Surface Science and Engineering
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• v.30 no.2
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• pp.93-103
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• 1997

High temperature materials used in the elevated temperature and corrosive atmosphere must have the good oxidation resistance and preserve their own mechanical properties simultaneously. For the oxidation resistance, it is very important to form a protective oxide scale such as $Al_2O_3$ or $Cr_2O_3$ on the substrate. However, the additions of protective oxide forming elements such as Cr and Al in the alloy to enhance its oxidation resistance are limited due to the deleterious effects on their mechanical properties. PECVD(P1asma Enhanced Chemical Vapor Deposition) coating processes were employed to improve the oxidation resistance at high temperature. Cr and/or A1 were coated on the substrates of Ni and Inconel 600 at various temperatures of 400, 500, $600^{\circ}C$ and at different conditions of specimen surfaces. Then, coated specimens were exposed to isothermal and cyclic oxidation conditions in air at 1000 and $1100^{\circ}C$. In order to enhance the adhesion between the substrate and coated layer, heat treatments of the coated specimens were conducted in a vacuum. At isothermal oxidation experiments, Al-coated Ni specimen showed better oxidation resistance than pure Ni. At cyclic oxidation experiments at $1000^{\circ}C$. Cr and Al-coated specimen showed better oxidation resistance. Cr-coated Inconel 600 had also showed better oxidation resistance due to Cr in the substrate. By PECVD coating process, oxidation resistance could be improved, but it was not improved as expected due to the weakness of the adhesion between the substrate and the coated layer.

• Korean Journal of Materials Research
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• v.31 no.11
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• pp.608-613
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• 2021

This study investigated the reaction between clay and Mn. Mn was coated using a manganese sulfate on porcelain plate and sintered from 1,100 ℃ to 1,250 ℃. The body begin to shrink around 950 ℃ with the increase in temperature and rapidly progressed after 1,100 ℃. Shrinkage of celadon body was performed at a lower temperature than for other substrates. Quartz, kaolin, and feldspar were the main crystalline phases of the starting materials, but they became mullite and crystobalite during the firing process, and some formed amorphous glass. When manganese sulfate was applied and fired, manganese oxide was fused, and some manganese oxide reacted with the substrate to show a dense microstructure different from that of the substrate; the substrate had pores. The manganese coated porcelain fired at 1,200 ℃ had L^* values of 55.25, 36.87, and 37.13 for the white ware, celadon body, and white mixed ware, respectively; with a^* values of 4.63, 3.07, and 2.15, and b^* values of 7.93 and 3.98, it was found to be 3.42. This result indicated that the color of the surface was affected during firing by the chemical reaction between the substrate and manganese.