• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.2
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• pp.31-43
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• 2002

Screen printing is a stencil process whereby ink is transferred to the substrate through a stencil supported by a fine fabric mesh. Therefore screen had a tendency to distort and swell, as ink was deposited between the fibers, and were difficult to clean. The tow importance of stencil parameters that affect print quality are stencil thread diameter and the fabric thickness because of their influence on both ink deposit and print definition. Since screen printing inks can be formulated to adhere to almost any surface, and the printing process itself can be handled almost any substrate in a wide variety of shape, screen printing is a very versatile process. The small size pronting is reproduced image used screen printing because the surface of substrates is not suited at screen printing method. In screen printing, the need of high definition printing is gradually increasing according to developing special inks. A conventional haftone, so called AM screening, is simple and easy to implement, but the haftone dot patterns by using this method are not free for the moire fringe. This paper is used densitometry and image analysis to investigate relation with printing according to screen mesh, opening size and resolution of copy in image reproduction used FM screen. We had the good result of dot gain and tone reproduction on the screen printing of high definition using FM screen.

• 한국균학회소식:학술대회논문집
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• 2018.05a
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• pp.29-29
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• 2018

Sparassis latifolia is called "Cauliflower Mushroom" and is known as an edible mushroom that has high content of ${\beta}$-glucan. Recently, artificial cultivation of S. latifolia has been done by bottle, plastic bag and wood cultivation in Korea. However it is not widely used because there are low incubation ratio and yield. For the high efficiency of production, we aim to find the superior strains and media for better mycelial and fruit body growth. First, we analyzed the genetic relationship among 31 strains and divided five groups with three kinds of URP primers. And then ten strains were selected from five groups based on the experiment of mycelial growth. The suitability of media for mycelial growth was different according to media type. The suitable solid and liquid media for mycelial growth of S. latifolia isolates were PDA and M2, respectively. In addition, with regard to C/N ratio, the mycelial growth increased even until C/N 160. Second, we investigated the production of fruitbody of the strains by plastic bag cultivation. The substrate was mixed with larch sawdust, corn flour, and wheat flour (8:1:1, v/v). Moisture content of substrate was controlled by about 60% with 10% molasses solution. Out of 31 strains, 19 strains formed primordia. The eight strains produced more than 140g/1kg in fresh weight. Third, molasses culture media was selected for the mycelial growth. And molasses suitable sugar content and input aeration were around 8Brix% and 0.3~0.6vvm, respectively. The longer the incubation period is, the more dried weight of mycelia increased, but medium volume decreased. Therefore, the best incubation period was 9 to 11 days depending on strains. In the future, research project entitled development of culture system and new variety for stable production of S. latifolia will be considered as a new item.

• Applied Biological Chemistry
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• v.50 no.1
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• pp.12-17
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• 2007

A biosurfactant-producing strain, Bacillus subtilis TBM 3101 was isolated from the soil sample at Tae-Baek Mountain through an antifungal test and emulsification assessment. The strain was assessed, regarding to the microbial growth, by physical and chemical test, surface tension, emulsification activity and stability. The surface tension of the isolate sharply decreased to the minimum 29mN/m at 48 h growth. Of note, its emulsification was stabilized to the highest degree when tributyrin was utilized as a substrate, indicating that in comparison to a variety of synthetic surfactants, the biosurfactant produced by the isolate was significantly similar to synthetic surfactant, tween 20. In addition, the biosurfactant showed high emulsification activity when soybean oil, crude oil and tetradecane were used as a substrate. Thus, these studies could contribute to the detection and development of biosurfactant beneficial to the environment and humans.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.491-505
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• 2020

A newly isolated strain, Proteus vulgaris OR34, from olive mill waste was found to secrete an alkaline extracellular lipase at 11 U·ml-1 when cultivated on an optimized liquid medium. This lipase was purified 94.64-fold with a total yield of 9.11% and its maximal specific activity was shown to be 3232.58 and 1777.92 U·mg-1 when evaluated using the pH-stat technique at 55℃ and pH 9 and Tributyrin TC4 or olive oil as the substrate. The molecular mass of the pure OR34 lipase was estimated to be around 31 kDa, as revealed by SDS-PAGE and its substrate specificity was investigated using a variety of triglycerides. This assay revealed that OR34 lipase preferred short and medium chain fatty acids. In addition, this lipase was stable in the presence of high concentrations of bile salt (NaDC) and calcium ions appear not to be necessary for its activity. This lipase was inhibited by THL (Orlistat) which confirmed its identity as a serine enzyme. In addition, the immobilization of OR34 lipase by adsorption onto calcium carbonate increased its stability at higher temperatures and within a larger pH range. The immobilized lipase exhibited a high tolerance to organic solvents and retained 60% of its activity after 10 months of storage at 4℃. Finally, the OR34 lipase was applied in biodiesel synthesis via oleic acid mediated esterification of methanol when using hexane as solvent. The best conversion yield (67%) was obtained at 12 h and 40℃ using the immobilized enzyme and this enzyme could be reused for six cycles with the same efficiency.

• Membrane Journal
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• v.31 no.6
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• pp.393-403
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• 2021

Enzymes are important class of catalyst for biotransformation. Stability and reusability of enzymes during the catalysis process is a key issue. Activity of enzyme can be enhanced by its immobilization on a suitable substrate by creation of specific microenvironment. A variety of membranes has been used as substrate due to the biocompatibility and simpler method to tune hydrophilicity/hydrophobicity property of the membrane surface. In this review, polymer membranes including cellulose, polyacrylonitrile (PAN), polydimethylsiloxane (PDMS), polyvinylidene fluoride (PVDF), polyethersulfone (PES) are introduced and discussed in detail. Biodegradation of organic contaminants by immobilized enzyme is an environmental friendly process to reduce the contamination of environment in pharmaceutical company and textile industries. The controlled hydrolysis of oil can be performed in enzyme immobilized membrane bioreactor (EMBR), resulting in reducing carbon emission and reduced environmental pollution. Bioethanol and biodiesel are considered alternative fossil fuels that can be prepared in EMBR.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.233-243
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• 2013

The inorganic pearlescent pigment have high physical and chemical stability, thus it is used in a variety field, which has better light stability, solvent resistance and thermostability. In this paper, we were synthesized the pearlescent pigment for cosmetics which was coated cobalt chloride for base of blue color metal oxide on mica titania substrate using hydrothermal synthesis method. To complement the color of the pigment by cobalt, pearl pigment were coated by different metal salt and cobalt ratio, to implement a variety of color value, depending on the kind of metal salts were synthesized. Synthesized pearlescent pigments appear various color as kind of added metal salt precursor and molar ration of cobalt and other metals. We controlled coating and color by composition of metal salt and type of metal salts, and that confirm the pigment characteristics of color changes through the analysis of color difference meter. Synthesized pigment was characterized by SPM, SEM, XRD, and EDS.

• Mycobiology
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• v.43 no.3
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• pp.184-194
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• 2015

A compressive description of tropical milky white mushroom (Calocybe indica P&C var. APK2) is provided in this review. This mushroom variety was first identified in the eastern Indian state of West Bengal and can be cultivated on a wide variety of substrates, at a high temperature range ($30{\sim}38^{\circ}C$). However, no commercial cultivation was made until 1998. Krishnamoorthy 1997 rediscovered the fungus from Tamil Nadu, India and standardized the commercial production techniques for the first time in the world. This edible mushroom has a long shelf life (5~7 days) compared to other commercially available counterparts. A comprehensive and critical review on physiological and nutritional requirements viz., pH, temperature, carbon to nitrogen ratio, best carbon source, best nitrogen source, growth period, growth promoters for mycelia biomass production; substrate preparation; spawn inoculation; different supplementation and casing requirements to increase the yield of mushrooms has been outlined. Innovative and inexpensive methods developed to commercially cultivate milky white mushrooms on different lignocellulosic biomass is also described in this review. The composition profiles of milky white mushroom, its mineral contents and non-enzymatic antioxidants are provided in comparison with button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Antioxidant assay results using methanol extract of milky white mushroom has been provided along with the information about the compounds that are responsible for flavor profile both in fresh and dry mushrooms. Milky white mushroom extracts are known to have anti-hyperglycemic effect and anti-lipid peroxidation effect. The advantage of growing at elevated temperature creates newer avenues to explore milky white mushroom cultivation economically around the world, especially, in humid tropical and sub-tropical zones. Because of its incomparable productivity and shelf life to any other cultivated mushrooms in the world, milky white mushroom could play an important role in satisfying the growing market demands for edible mushrooms in the near future.

• Journal of Mushroom
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• v.22 no.3
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• pp.112-116
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• 2024

We developed a new oyster mushroom cultivar named 'Dawon-tari', which has a longer stipe and higher yield than those of 'sootari'.'Dawon-tari' was crossed by mating monokaryons isolated from 'Sootari' and 'Daejang2ho'. The optimal temperature for mycelial growth was determined to be 20~25℃ on potato dextrose agar medium, while the optimal temperatures for primordia formation and fruiting body growth were 15~17℃ on a sawdust substrate. During bottle cultivation, the mycelial growth phase required approximately 26 days. Additionally, primordia formation required 5 days, and fruiting body growth took 4 days. The fruiting bodies exhibited a shallow funnel shape; were grayishbrown; and the stipes were characterized by a long, thin structure. The yield of fruiting bodies was 185 g per 1,100 mL bottle, which was 5% higher than that of 'Sootari'.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.409-409
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• 2014

Recently hexagonal boron nitride (h-BN), III-V compound of boron and nitrogen with strong covalent $sp^2$ bond, is a 2 dimensional insulating material with a large direct band gap up to 6 eV. Its outstanding properties such as strong mechanical strength, high thermal conductivity, and chemical stability have been reported to be similar or superior to graphene. Because of these excellent properties, h-BN can potentially be used for variety of applications such as dielectric layer, deep UV optoelectronic device, and protective transparent substrate. Ultra flat and charge impurity-free surface of h-BN is also an ideal substrate to maintain electrical properties of 2 dimensional materials such as graphene. To synthesize a single or a few layered h-BN, chemical vapor deposition method (CVD) has been widely used by using an ammonia borane as a precursor. Ammonia borane decomposes into hydrogen (gas), monomeric aminoborane (solid), and borazine (gas) that is used for growing h-BN layer. However, very active monomeric aminoborane forms polymeric aminoborane nanoparticles that are white non-crystalline BN nanoparticles of 50~100 nm in diameter. The presence of these BN nanoparticles following the synthesis has been hampering the implementation of h-BN to various applications. Therefore, it is quite important to grow a clean and high quality h-BN layer free of BN particles without having to introduce complicated process steps. We have demonstrated a synthesis of a high quality h-BN monolayer free of BN nanoparticles in wafer-scale size of $7{\times}7cm^2$ by using CVD method incorporating a simple filter system. The measured results have shown that the filter can effectively remove BN nanoparticles by restricting them from reaching to Cu substrate. Layer thickness of about 0.48 nm measured by AFM, a Raman shift of $1,371{\sim}1,372cm^{-1}$ measured by micro Raman spectroscopy along with optical band gap of 6.06 eV estimated from UV-Vis Spectrophotometer confirm the formation of monolayer h-BN. Quantitative XPS analysis for the ratio of boron and nitrogen and CS-corrected HRTEM image of atomic resolution hexagonal lattices indicate a high quality stoichiometric h-BN. The method presented here provides a promising technique for the synthesis of high quality monolayer h-BN free of BN nanoparticles.

• Journal of Mushroom
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• v.13 no.1
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• pp.74-78
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• 2015

The 'Heuktari', a new mid-high temperature adaptable variety of oyster mushroom for the bottle culture, was bred by mating with monokaryons isolated from 'P11056' and 'MT07156'. The optimum temperature for the mycelial growth was $23{\sim}26^{\circ}C$ on PDA medium and that for the primordia formation and the growth of fruiting body of 'Heuktari' was $18{\sim}19^{\circ}C$ on sawdust substrate. In case of bottle cultivation, the period of mycelial growth was required about 30 days. In addition, the period of primordia formation and growth of fruiting body was 4 days and 5 days, respectively. In the characteristics of fruiting body, shape and color of pilei were round type and dark grayish brown, stipe color was white color and stipe shape was short and thick. The yield of fruiting bodies was 180 g/900 ml bottle which was 15% higher than that of Suhan-1ho. The gumminess and brittleness of stipe tissue were 110% and 140% stronger than those of Suhan-1ho, respectively.