• Journal of the Korean Ceramic Society
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• v.31 no.1
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• pp.88-96
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• 1994

Hot filament-assisted CVD was carried out to deposit diamond films on Si(100) substrate at 90$0^{\circ}C$ using a 1% CH4-H2 mixture gas. Deposition was made at various conditions of mass flow rate of the feed gas (30~1000 sccm), pressure (2.5~300 Torr), and filament-substrate distance (4~15 mm), and the deposited films were characterized by SEM, XRD, and Raman spectroscopy. As the flow rate increases, the growth rate also increased but the crystallinity of the film was degraded. A longer filament-substrate distance simply caused both the growth rate and the crystallinity to become poorer. On the other hand, the pressure variation resulted in a maximum growth rate of 2.6 ${\mu}{\textrm}{m}$/hr at 10 Torr and the best film quality around 50 Torr, exhibiting an optimum condition. The observed trends were interpreted in terms of the flow velocity-dependent pyrolysis reaction efficiency and mass transport through the boundary layer.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.12
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• pp.560-564
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• 2006

ZnO thin films were prepared by RF magnetron sputter deposition on p-Si(100) wafer with various cooling rates of substrate temperature such as the substrates were pre-heated to $400^{\circ}C$ before the deposition and then cooled down naturally or slowly to $300^{\circ}C,\;200^{\circ}C,\;100^{\circ}C$, and R.T. by the temperature controller during the deposition. Crystalline and micro-structural characteristics of the films were investigated by XRD and SEM. ZnO films which cooled down naturally or slowly by the temperature controller during the deposition, especially the film were deposited with cooling down from $400^{\circ}C\;to\;200^{\circ}C$ slowly. showed the most outstanding c-axis preferred orientation.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.804-806
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• 2007

C-axis oriented zinc oxide thin films were deposited on Si(100) substrate by rf magnetron sputtering. The effects of deposition parameters on the crystallinity and electrical properties of ZnO films were investigated. As-deposited ZnO films showed the strong c-axis growth andexcellent crystallinity under the deposition conditions as follows ; substrate temperaturec : $200^{\circ}C$, rf power : 150W, gas ratio : $O_2/Ar=50/50$, chamber pressure : 10mTorr. The resistivity of ZnO films was significantly affected by deposition parameters. With increasing percentage of oxygen, and decreasing substrate temperature, the resistivity of ZnO films increased.

• Bulletin of the Korean Chemical Society
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• v.17 no.10
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• pp.905-908
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• 1996

A substrate specificity of cabbage phospholipase D (PLD) was studied using the synthetic phospholipids having different head groups. The phospholipids were synthesized from phosphatidylcholine and appropriate bases by transphosphatidylation of PLD. The bases used were ethanolamine, serine, ethanol and γ-hydroxybutyric acid. The phosphatidic acid, the product of PLD, was separated in TLC and measured densitometrically. The kinetic parameters were estimated for each substrate and the effects of pH, SDS, Ca2+ and other metal ions were examined. Vmax values found were 3.75, 2.36, 5.59, 1.63, 2.30 nmol/min/μg protein for phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylethanol, and phosphatidylburytic acid, respectively. These results indicate a broad specificity of cabbage PLD toward phospholipids with different head groups. Particularly phosphatidylserine was most easily hydrolyzed by PLD and its activity did not depend on Ca2+.

• Journal of the Korean institute of surface engineering
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• v.28 no.5
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• pp.309-319
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• 1995

The substrate patterned with the dry film has the cavity which has the $90^{\circ}$ wall angle. Electroplating Cu on this patterned substrate has the differrent shape history with the electrochemical parameters. By potential theory model, the reason of the variation of the shape change with the these parameters was investigated. The shape history could be explained by the current flow and the correlated area effects. By embedding the Ni layer between the Cu layers, shape history with the time was obtained experimentally and the results was compared with the numerical analysis by BEM. The adhesive Cr-Cu film in TAB application was etched with the various condition. The best condition for the etchant of the Cr-Cu film was found.

• Journal of electromagnetic engineering and science
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• v.18 no.3
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• pp.160-168
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• 2018

A wide spectrum of potential applications using substrate integrated waveguide (SIW) technologies in conjunction with air hole regions is introduced, and an efficient optimization methodology to cope with the multiple air hole effect in SIW applications is proposed. The methodology adopts a genetic algorithm to obtain optimum air hole dimensions for the specific propagation constant that can be accurately calculated using the recursive and closed form equations presented. The optimization results are evaluated by designing an SIW bandpass filter, and they show excellent performance. The optimization methodology using the proposed equations is effective in performance enhancement for the purposes of low loss and broadband SIW applications.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.142-148
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• 1995

Sb ${\delta}$-doped Si layers were grown by Si MBE (Molecular Beam Epitaxy) system using substrate temperature modulation technique. The Si substrate temperatures were modulated between 350$^{\circ}C$ and 600$^{\circ}C$. The doping profile was as narrow as 41$\AA$ and the doping concentration of up to 3.5${\times}10^{20}cm^{3}$ was obtained. The film quality was as good as bulk material as verified by RHEED (Reflected High Energy Electron Diffraction), SRP (Spreading Resistance Profiling) and Hall measurement. Since the film quality is not degraded after the growth a Sb ${\delta}$-doped Si layer, the ${\delta}$-doped layers can be repeated as many times as we want. The doping technique is useful for many Si devices including small scale devices and those which utilize quantum mechanical effects.

• Proceedings of the Korean Magnestics Society Conference
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• 2002.12a
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• pp.140-141
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• 2002

In proto-type microactuators driven by magnetostrictive Tb-Fe thin films, the deflection was observed to be much smaller than that expected from large-sized "standard" Tb-Fe thin films. A striking difference was observed when the results from a thin substrate of 28 $\mu\textrm{m}$ for microactuator applications were compared with those from a standard substrate. At a standard substrate thickness (several hundred $\mu\textrm{m}$), an amorphous phase was formed and the coercivity was low being 80 Oe. (omitted)

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.249-255
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• 1990

High Tc Supperconducting thin films were fabricated by rf magnetron sputtering method. We have successfully controlled the compositions of films by adding sintered CuO pellets on YBa2Cu3O7-x single target. High Tc thin films with large grian size and good crystal habit were obtained by rapid thermal annealing process. The films deposited on SrTiO3(100) single crystal substrate indicated the existence of c-axis prefered orientation confirmed by XRD and SEM analysis. The Tc, zero's of sharp resistive transition for rapid annealed films deposited on polycrystalline YSZ substrate and on SrTiO3(100) single crystal substrate were 79K and 88K, respectively.

• The Microorganisms and Industry
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• v.20 no.3
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• pp.70-73
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• 1994

Effects of 13 organic compounds including glucose, fructose, xylose, glutamate, succinate, malate, glycine, lactate, acetate, pyruvate, citrate, formate and cis-aconitate on the oxidation of thiosulfate and the availability of these compounds as the substrate for the respiration by Thiobacillus ocncretivorus, which is known to be an obligated autotroph, were studied. Malate nad glycine at 0.5 per cent concentration nearly doubled the thiosulfate oxidation compared to the control. No other organic substances enhanced the thiosulfate oxidation compared to the control. No other organic substances enhanced the thiosulfate oxidation. Moreover, some 30 to 40 per cent decrease was recorded by fructose, sulfate-salts medium, some 30 to 40 per cent decrease was recorded by fructose, citrate, xylose, malate, flucose, glutamate and succinate. No respiration could occur when formate and pyruvate were supplied as the substrate for respiration. But it was obvious that flucose, fructose, xylose, glutamate, malate, citrate and succinate could be used as the substrate for respiration to some extent, regarding the fact that some increase in respiration rates could be recorded compared to the result from the salts medium, where neither thiosulfate nor orgnic compounds were added. Thus, it was postulated that this organism could possibly be converted into mixotroph or hetrotroph if appropriate conditions could be prepared.