• Journal of Mushroom
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• v.15 no.2
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• pp.88-93
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• 2017

This study was carried out to establish a cultivation technique for increasing the ${\gamma}$-aminobutyric acid (GABA) content in the fruit body of mushrooms by adding processed by-products. For the oyster mushroom 'Heucktari', addition of green tea powder, sea tangle powder, and green tea dregs resulted in very poor primordia formation, fruit body growth, and increased GABA. However, addition of 10% schizandra berry dregs and 1% rice bran to the basal substrate induced 100% and 10% increases, in GABA content in the fruit bodies compared to the control treatment without by-product, respectively. In addition, fruit body growth and primordia formation were greatly increased by these treatments. Therefore, GABA content was increased when the substrate was prepared by mixing an appropriate amount of schizandra berry dregs and rice bran.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.2
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• pp.55-59
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• 2015

Novel low-volume solder-on-pad (SoP) process is proposed for a fine pitch Cu pillar bump interconnection. A novel solder bumping material (SBM) has been developed for the $60{\mu}m$ pitch SoP using screen printing process. SBM, which is composed of ternary Sn-3.0Ag-0.5Cu (SAC305) solder powder and a polymer resin, is a paste material to perform a fine-pitch SoP in place of the electroplating process. By optimizing the volumetric ratio of the resin, deoxidizing agent, and SAC305 solder powder; the oxide layers on the solder powder and Cu pads are successfully removed during the bumping process without additional treatment or equipment. The Si chip and substrate with daisy-chain pattern are fabricated to develop the fine pitch SoP process and evaluate the fine-pitch interconnection. The fabricated Si substrate has 6724 under bump metallization (UBM) with a $45{\mu}m$ diameter and $60{\mu}m$ pitch. The Si chip with Cu pillar bump is flip chip bonded with the SoP formed substrate using an underfill material with fluxing features. Using the fluxing underfill material is advantageous since it eliminates the flux cleaning process and capillary flow process of underfill. The optimized interconnection process has been validated by the electrical characterization of the daisy-chain pattern. This work is the first report on a successful operation of a fine-pitch SoP and micro bump interconnection using a screen printing process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.259-259
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• 2008

The LTCC (Low Temperature Co-fired Ceramic) technology meets the requirements for high quality microelectronic devices and microsystems application due to a very good electrical and mechanical properties, high reliability and stability as well as possibility of making integrated three dimensional microstructures. The wet process, which has been applied to the etching of the metallic thin film on the ceramic substrate, has multi process steps such as lithography and development and uses very toxic chemicals arising the environmental problems. The other side, Plasma technology like ion beam sputtering is clean process including surface cleaning and treatment, sputtering and etching of semiconductor devices, and environmental cleanup. In this study, metallic multilayer pattern was fabricated by the ion beam etching of Ti/Pd/Cu without the lithography. In the experiment, Alumina and LTCC were used as the substrate and Ti/Pd/Cu metallic multilayer was deposited by the DC-magnetron sputtering system. After the formation of Cu/Ni/Au multilayer pattern made by the photolithography and electroplating process, the Ti/Pd/Cu multilayer was dry-etched by using the low energy-high current ion-beam etching process. Because the electroplated Au layer was the masking barrier of the etching of Ti/Pd/Cu multilayer, the additional lithography was not necessary for the etching process. Xenon ion beam which having the high sputtering yield was irradiated and was used with various ion energy and current. The metallic pattern after the etching was optically examined and analyzed. The rate and phenomenon of the etching on each metallic layer were investigated with the diverse process condition such as ion-beam acceleration energy, current density, and etching time.

• Current Photovoltaic Research
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• v.1 no.2
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• pp.103-108
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• 2013

Epitaxial growth of a high-quality thin Si film is essential for the application to low-cost thin-film Si solar cells. A polycrystalline Si film was grown on a $SiO_2$ substrate at $450^{\circ}C$ by a Al-assisted crystal growth process. For the purpose, a thin Al layer was deposited on the $SiO_2$ substrate for Al-assisted crystal growth. However, the epitaxial growth of Si film resulted in a rough surface with humps. Then, we introduced a thin amorphous Si seed layer on the Al film to minimize the initial roughness of Si film. With the help of the Si seed layer, the surface of the epitaxial Si film was smooth and the crystallinity of the Si film was much improved. The grain size of the $1.5-{\mu}m$-thick Si film was as large as 1 mm. The Al content in the Si film was 3.7% and the hole concentration was estimated to be $3{\times}10^{17}/cm^3$, which was one order of magnitude higher than desirable value for Si base layer. The results suggest that Al-doped Si layer could be use as a seed layer for additional epitaxial growth of intrinsic or boron-doped Si layer because the Al-doped Si layer has large grains.

• Tribology and Lubricants
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• v.37 no.6
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• pp.240-245
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• 2021

Ceramic coatings with high hardness and excellent chemical stability have been successfully applied to various machine elements, tools, and implants. However, in the case of monolayer coating on soft substrates, a high-stress concentration at the interface between the coating and the substrate causes delamination of the coating layer. Recently, to overcome this problem, multilayer coatings with a metal layer with a low modulus of elasticity added between the ceramic and the substrate have been widely applied. This study presents the third part of a recent study and focuses on the effect of the number of coating layers on the Brinell hardness of multilayered coating with TiN/Ti, following the two previous studies on a new Brinell hardness test method for a coated surface and on the influence of substrate and coating thickness. Indentation analyses are performed using finite element analysis software, von Mises stress and equivalent plastic strain distributions, load-displacement curves, and residual indentation shapes are presented. The number of TiN/Ti layers considerably affect the stress distributions and indentation shapes. Moreover, the greater the number of TiN/Ti layers, the higher is the Brinell hardness. The stress and plastic strain distributions confirm that the multilayer coatings improve the wear resistance. The results are expected to be used to design and evaluate various coating systems, and additional study is required.

• Journal of Mushroom
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• v.7 no.4
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• pp.156-162
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• 2009

These experiments were carried out to determine the optimal culture conditions for nine strains of collected Hatakeshimeji, Lyophyllum decastes (Fr.:Fr.) Sing. SPA 202 and SPA 205 strains were selected because mycelium grew fast and showed fine density. All strains showed fast mycelial growth and mycelial density on BC(Burke compost) media for 20 days of incubation. The optimal sawdust species for the mycelial growth were the fermented sawdusts of Quercus aliena and Populus deltoides. Spawn running period on the fermented sawdust substrate required 50 days at 20 to $25^{\circ}C$ and additional 7 days after soil casing. Cultivation period and temperature forprimordia formation and fruitbody development appeared from 10 to 11 days and from 7 to 8 days at 17 to $18^{\circ}C$ respectively. The length of pilei and stipes of SPA 202 harvested in optimal stage showed 60mm and 67mm, respectively. Yield of SPA 202 strain grown on fermented sawdust substrate was 130g per 1,100ml in bottle cultivation. The length of pilei and stipes of SPA 205harvested in optimal stage showed 51mm and 81mm, respectively. Yield of SPA 205 strain grown on fermented sawdust substrate was 129g per 1,100 ml in bottle cultivation. SPA 202 strain and SPA 205 strain in artificial bottle cultivation of Lyophyllum decastes used in fermented sawdust substrate were selected as themost appropriate strain in yield.

• Korean Journal of Materials Research
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• v.20 no.4
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• pp.175-180
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• 2010

Transparent conducting oxide (TCO) films are widely used for optoelectronic applications. Among TCO materials, zinc oxide (ZnO) has been studied extensively for its high optical transmission and electrical conduction. In this study, the effects of $O_2$ plasma pretreatment on the properties of Ga-doped ZnO films (GZO) on polyethylene naphthalate (PEN) substrate were studied. The $O_2$ plasma pretreatment process was used instead of conventional oxide buffer layers. The $O_2$ plasma treatment process has several merits compared with the oxide buffer layer treatment, especially on a mass production scale. In this process, an additional sputtering system for oxide composition is not needed and the plasma treatment process is easily adopted as an in-line process. GZO films were fabricated by RF magnetron sputtering process. To improve surface energy and adhesion between the PEN substrate and the GZO film, the $O_2$ plasma pre-treatment process was used prior to GZO sputtering. As the RF power and the treatment time increased, the contact angle decreased and the RMS surface roughness increased significantly. It is believed that the surface energy and adhesive force of the polymer surfaces increased with the $O_2$ plasma treatment and that the crystallinity and grain size of the GZO films increased. When the RF power was 100W and the treatment time was 120 sec in the $O_2$ plasma pretreatment process, the resistivity of the GZO films on the PEN substrate was $1.05\;{\times}\;10^{-3}{\Omega}-cm$, which is an appropriate range for most optoelectronic applications.

• Journal of Plant Biotechnology
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• v.5 no.3
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• pp.149-155
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• 2003

Metabolic engineering for production of isoflavones in nonlegume plants could distribute the health benefits of these phytoestrogens in more widely-consumed grains. Series of investigation to check the ability of the heterologous isoflavone synthase enzyme to interact with the endogenous phenylpropanoid pathway have been conducted. Overall, results provide possibility of production of isoflavonoids in several plant tissue systems including soybean and nonlegumes. In tissue that undergoes naturally enhanced synthesis of anthocyanins, genistein production was enhanced. In a monocot cell system, introduced expression of a transcription factor regulating genes of the anthocyanin pathway was effective in conferring the ability to produce genistein in the presence of the isoflavone synthase gene. However, in this case the intermediate accumulated to high levels indicating an inefficiency in its conversion. Introduction of a third gene, chalcone reductase, provided the ability to synthesize an additional substrate of isoflavone synthase resulting in production of the isoflavone daidzein. These research efforts provide insight into requirements for metabolic engineering for isoflavone production in nonlegume dicot and monocot tissues.

• Journal of Environmental Health Sciences
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• v.15 no.2
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• pp.41-49
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• 1989

The assay on microbial dehydrogenase activity by using TTC was investigated. The experimental results are summarized as follows: 1. The TF production was affected by dissolved oxygen. Dissolved oxygen in samples could be effectively removed by adding $Na_{2}SO_{3}$ as reductant prior to incubation. 2. The toxic effect on TF formation was observed at up to 0.1% of final TTC concentration when VSS concentration was 2.7g/l. As the VSS concentration increased the effect decreased. 3. It was clearly revealed that the TF generation rate decreased with increasing VSS concentration. The dilution of sludge could be applicable when VSS level is below 3.5g/l. 4. The TF production of endogenous phase (De) could be used as a measure for the viable fraction of sludge over various sludge ages. The additional TF production (Ds) due to extracellular substrate responded to De, not to VSS concentration.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.77-84
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• 2003

Metabolic engineering for production of isoflavones in non-legume plants could distribute the health benefits of these phytoe-strogens in more widely-consumed grains. We investigate the ability of the heterologous isoflavone synthase enzyme to interact with the endogenous phenylpropanoid pathway. Overall, results provide possibility of production of isoflavonoids in several plant tissue systems including soybean and non-legumes. In tissue that undergoes naturally enhanced synthesis of anthocyanins, genistein production was enhanced. In a monocot cell system, introduced expression of a transcription factor regulating genes of the antho-cyanin pathway was effective in conferring the ability produce genistein in the presence of the isoflavone synthase gene. However, in this case the intermediate accumulated to high levels indicating an inefficiency in its conversion. Introduction of a third gene, chalcone reductase, provided the ability to synthesize an additional substrate of isoflavone synthase resulting in production of the isoflavone daidzein. These research efforts provide insight into requirements for metabolic engineering for isoflavone production in non-legume dicot and monocot tissues.