• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1847-1855
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• 2015

Supercritical carbon dioxide ($SC-CO_2$) treatment has been becoming an important method for substituting the use of organic solvents for samples extraction prior to analysis due to its low toxicity, ease of handling, low cost of disposal etc. Freeze-dried bovine liver was treated with $SC-CO_2$ under different pressures (200, 300, and 450 bar) in order to investigate effects on physicochemical properties and reduction of microbial load. The yield of lipid extraction from bovine liver by $SC-CO_2$ treatment increased with increasing pressure, with values of 84, 86, and 90% in response to 200, 300, and 450 bar, respectively. Results of high performance liquid chromatography analysis showed that vitamin A and coenzyme $Q_{10}$ ($CoQ_{10}$), which is soluble in lipid, were almost removed from bovine liver by $SC-CO_2$ treatment. Saturated fatty acids ratio of bovine liver decreased with increasing pressure, whereas polyunsaturated fatty acids increased with increasing pressure. Total content of amino acids in bovine liver treated by $SC-CO_2$ was less than that of the control sample without treatment. The number of aerobic bacteria in bovine liver, which was stored at $5^{\circ}C$ for 5 days and freeze-dried, decreased from 6.2 to 4.2 log CFU/g by $SC-CO_2$ treatment at 100 bar for 3 h. Interestingly, coliform bacteria were not found in the bovine liver sample by $SC-CO_2$ at 100 bar for 3 h under all storage conditions. This indicates that $SC-CO_2$ treatment can effectively reduce coliform bacteria in the food matrix even at low moisture. In conclusion, freeze-dried bovine liver by proper $SC-CO_2$ treatment may be used as a potential high protein source, with increasing microbial safety and stability of lipid oxidation.

• Journal of the Korean Ceramic Society
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• v.53 no.4
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• pp.393-399
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• 2016

We have successfully fabricated 3D (3-dimensional) nanostructures of $TiO_2$ coated with a $g-C_3N_4$ layer via hydrothermal and sintering methods to enhance photoelectrochemical (PEC) performance. Due to the coupling of $TiO_2$ and $g-C_3N_4$, the nanostructures exhibited good performance as the higher conduction band of $g-C_3N_4$, which can be combined with $TiO_2$. To fabricate 3D nanostructures of $g-C_3N_4/TiO_2$, $TiO_2$ was first grown as a double layer structure on FTO (Fluorine-doped tin oxide) substrate at $150^{\circ}C$ for 3 h. After this, the $g-C_3N_4$ layer was coated on the $TiO_2$ film at $520^{\circ}C$ for 4 h. As-prepared samples were varied according to loading of melamine powder, with values of loading of 0.25 g, 0.5 g, 0.75 g, and 1 g. From SEM and TEM analysis, it was possible to clearly observe the 3D sample morphologies. From the PEC measurement, 0.5 g of $g-C_3N_4/TiO_2$ film was found to exhibit the highest current density of $0.12mA/cm^2$, along with a long-term stability of 5 h. Compared to the pristine $TiO_2$, and to the 0.25 g, 0.75 g, and 1 g $g-C_3N_4/TiO_2$ films, the 0.5 g of $g-C_3N_4/TiO_2$ sample was coated with a thin $g-C_3N_4$ layer that caused separation of the electrons and the holes; this led to a decreasing recombination. This unique structure can be used in photoelectrochemical applications.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.95-100
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• 2004

The main objectives of the study were to investigate cultural characteristics of Phellinus linteus. The optimum culture media for mycelial growth of P. linteus were MYA (malt yeast agar) and SMS (soybean powder malt Sucrose). Similarly, optimum temperature and pH were $30^{\circ}C$ and 6.0, respectively. Malt extract (2%, v/v) and yeast extract (0.2%, v/v) were optimum carbon and nitrogen sources. Similarly, 0.1% $KH_2PO_4$ was optimum mineral salt. Highest mycelial growth was observed when C/N ratio was 10 : 1. Optimum inoculum amount for flask culture was $5{\sim}6$ mycelial discs (6 mm diameter) per 100 ml of liquid medium, Highest mycelial dry weight was obtained when cultured in 100 ml liquid medium in 300 ml shaking flask after 20 days of shaking culture, For mass liquid culture (8 l), flask culture was homogenized and used as an inoculum. Optimum culture period and aeration rate for 8l fermentation culture were 12 days and 2.0 vvm, respectively.

• The Korean Journal of Mycology
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• v.15 no.1
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• pp.42-47
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• 1987

4 strains of the oak mushroom Lentinus edodes including the strain ASI 3046 were collected home and abroad to investigate the characterics of mycelial growth on synthetic media and sawdust media. The possibility of artificial culture of Lentinus edodes on media composed of different saw dusts and adding materials was investigated. Results were as follows: The optimum temperature for growth ranged from $22^{\circ}C$ to $26^{\circ}C$ among the lineages of Lentinus edodes. The optimal growth temperature for ASI 3046 strain and ASI 3047 strain was $26^{\circ}C$ and $22^{\circ}C$, respectively. The optimal carbon source for ASI 3046 strain was glucose, and peptone and ammoinum tartrate were proved excellent as nitrogen sources. When Lentinus edodes was cultured on sawdust media by varying the mixing ratio of different sawdusts and adding materials, mixed sawdust media composed of oak sawdust(50%, v/v), poplar sawdust(50%, v/v), acorn powder(5%, v/v) and rice bran(10%, v/v) showed higher yields of fruit bodies. Results showed that the ideal strain of Lentinus edodes for artificial culture on sawdust media was strain ASI 3046.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.15-15
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• 2011

As you know, boron compounds, borax ($Na_2B_4O_5(OH)_4{\cdot}8H_2O$) etc. were known thousands of years ago. As for natural boron, it has two naturally occurring and stable isotopes, boron 11 ($^{11}B$) and boron 10 ($^{10}B$). The neutron absorption $^{10}B$ is included about 19~20% with 80~81% $^{11}B$. Boron is similar to carbon in its capability to form stable covalently bonded molecular networks. The mass difference results in a wide range of ${\beta}$ values between the $^{11}B$ and $^{10}B$. The $^{10}B$ isotope, stable with 5 neutrons is excellent at capturing thermal neutrons. For example, it is possible to decrease a thermal neutron required for the nuclear reaction of uranium 235 ($^{235}U$). If $^{10}B$ absorbs a neutron ($^1n$), it will change to $^7Li+^1{\alpha}$ (${\alpha}$ ray, like $^4He$) with prompt ${\gamma}$ ray from $^{11}B$ $^{11}B$ (equation 1). $$^{10}B+^1n\;{\rightarrow}\;^{11}B\;{\rightarrow}\; prompt \;{\gamma}\;ray (478 keV), \;^7Li+4{\alpha}\;(4He)\;\;\;\;{\cdots}\; (1)$$ If about 1% boron is added to stainless steel, it is known that a neutron shielding effect will be 3 times the boron free steel. Enriched boron or $^{10}B$ is used in both radiation shielding and in boron neutron capture therapy. Then, $^{10}B$ is used for reactivity control and in emergency shutdown systems in nuclear reactors. Furthermore, boron carbide, $B_4C$, is used as the charge of a nuclear fission reaction control rod material and neutron cover material for nuclear reactors. The $B_4C$ powder of natural B composition is used as a charge of a control material of a boiling water reactor (BWR) which occupies commercial power reactors in nuclear power generation. The $B_4C$ sintered body which adjusted $^{10}B$ concentration is used as a charge of a control material of the fast breeder reactor (FBR) currently developed aiming at establishment of a nuclear fuel cycle. In this study for new boron compound, silicon boride ceramics for capturing thermal neutrons, preparation and characterization of both silicon tetraboride ($SiB_4$) and silicon hexaboride ($SiB_6$) and ceramics produced by sintering were investigated in order to determine the suitability of this material for nuclear power generation. The relative density increased with increasing sintering temperature. With a sintering temperature of 1,923 K, a sintered body having a relative density of more than 99% was obtained. The Vickers hardness increased with increasing sintering temperature. The best result was a Vickers hardness of 28 GPa for the $SiB_6$ sintered at 1,923K for 1 h. The high temperature Vickers hardness of the $SiB_6$ sintered body changed from 28 to 12 GPa in the temperature range of room temperature to 1,273 K. The thermal conductivity of the SiB6 sintered body changed from 9.1 to 2.4 W/mK in the range of room temperature to 1,273 K.

• Journal of the Korean Ceramic Society
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• v.35 no.7
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• pp.721-725
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• 1998

In this study solid-phase sintered silicon caribide samples composed of SiC powder having boron and car-bon black as additives were prepared by pressureless sintering at $1950^{\circ}C$. The bending strength the frac-ture toughness and the specific werar rate of the samples were examined and the micro structures of the broken and the worn surface were observed by SEM to understand the relationship between the tri-bological charcteristics and the micro structure. Additionally the relationship between the micro struc-tures and the tribological characteristics of the samples for the frictional opponents SiC and $Al_{2}O_{3}$ pins were investigated Conclusions are as follows ; 1. The specific were rate of the samples for the SiC pin was larger than that for the $Al_{2}O_{3}$ pin. HOwever the specific wear rate for the $Al_{2}O_{3}$ pin was increased about 6,45 times as that for the SiC pin under the load increasing. 2. The specific wear rate of the SiC pin was larger than that of the $Al_{2}O_{3}$ pin. owever the specific wear rate of the $Al_{2}O_{3}$ pin was increased about 4 times as that of the SiC pin under the load increasing 3. The micro stucture of the worn surface showed a flat face without cracks in the case that the frictional opponents has the low friction coefficient but in the case of without cracks in the case that the frictional opponents has the low friction coefficient but in the case of the high friction coefficient the micro structure of the worn surface showed an uneven face having spread-ed cracks. 4. The tribological characteristics of thesolid-phase sintered SiC samples was similar to that of li-quid-phase sintered ones when the pin having the high friction coefficient was used.

• Applied Microscopy
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• v.25 no.4
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• pp.124-131
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• 1995

High resolution transmission electron microscopic observations on the $Hg_{1-x}\;Tl_{x}\;Ba_{2}(Ca_{0.86}\;Sr_{0.14})_{2}\;Cu_{3}\;O_{8+\delta}$(x=0.00, 0.25, 0.50, 0.75) were carried out using side-entry type TEM working at 300 kV. The TEM samples are prepared by powder method. The pellets are crushed in agatar motar and suspended in $CCl_4$, solution and scooped in holely carbon microgrid. The 1223 structures are observed in all samples with [010] zone axis. Except x=0.25 sample, the lattice parameter a and c tend to decrease as the thallium contents are increased ranging from 0.3936 nm to 0.3713 nm for a, and from 1.6131 nm to 1.5138 nm for c parameter. Those of x=0.25 sample are reduced too much, 0.3785 nm for a, 1.5375 nm for c. The sample with x=0.25 shows the intergrowth of 1223 and 1234 structure with the ratio of 19 to 1. As the thallium content increases, the structures become more stable without having any defect. The samples are damaged by electron beam irradiation during the observation, however the structure can endure longer as the thallium contents are increased.

• Journal of Mushroom
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• v.15 no.3
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• pp.145-149
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• 2017

This study was conducted to investigate the optimum additive ratio of barley flour when used instead of cotton seed meal for the cultivation of oyster mushrooms. Mycelial growth was the fastest to 11.4 cm in medium containing 5% barley flour and to 9.0 cm in medium containing 30% barley flour. The mycelial density was slightly lower at 5% and 10% of barley powder addition, but there was no significant difference between the other treatments. The yield of the fruiting bodies was 158 g/850 mL, which was highest on treatment with 10% barley flour as a substitute for cotton seed meal. However, this was lower on treatments with only barley flour than in the control (156 g/850 mL). The diameter of the pileus and the hardness of stipes were highest with 10% barley flour and 10% in cotton seed meal, respectively. The L value was highest with 10% added barley flour, but the a-value and the b-value were not significantly different between treatments. The pH of the mixed media before inoculation with Pleurotus ostreatus was 4.7-5.0, and the total nitrogen content was 1.7-2.2, which was slightly lower than that of the control. The total carbon content was 44.6-45.0, which was not significantly different from that of the control. However, the content of trace elements such as Cu and Fe was lower than those of the control.

• Applied Biological Chemistry
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• v.13 no.1
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• pp.29-34
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• 1970

In order to prepare digested Protein source for the Weanling Food from soybean, an attempt was made to decompose steamed soybean protein to amino acids and peptides by protease and cellulase produced from Aspergillus niger and Aspergillus sojae. In this paper, the optimum condition for digestion of soybean protein were studied and also investigated the effects of decolorization of it. As the results, followings were obtained; 1. As steaming conditions, a treatment under 15 lb of pressure and 10 minutes of heating shows most effective. 2. The optimum pH of Asp, sojae enzyme for the digestion of soybean protein is 6.0, while that of Asp. niger enzyme is 4.4. In successievly-decomposing with Asp. sojae and Asp. niger, it shows the most effective on ratio of water-soluble-nitrogen to total nitrogen and amino-nitrogen to total nitrogen than any other separate treatments. 3. The suitable amount of the enzyme solution to that of the soybean substrate paste, in volume, is 1 : 2. 4. Digestion ratio of soybean protein indicates the gradual and steady effects of increasing time of digestion, but 8 hour-digestion regarding to putrefaction was suitable. 5. The most effective decolorization was successively passed on culumns of active carbon and anion exchanger (Dowex 2-x-8) at room temperature. In separate treatments, the effective order of decolorization was as follows; (Dowex 2-x-8)>Active carborn>Amberite IR-120 6. The powder type of the soy protein source obtained by concentration below $60^{\circ}C$ contains 12.51% of moisture, 66.31% of protein, 4.25% of fat, 12.75% of carbohydrate, 4.18% of ash.

• The Korean Journal of Mycology
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• v.21 no.2
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• pp.94-105
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• 1993

The genus Cordyceps known as an insect parasite forms a sclerotium in insect bodies and then produces perithecia on the single or multiple stromata produced from sclerotium. Collected Cordyceps were identified into 5 species: Cordyceps militaris, C. nutans, Cordyceps sphecocephala, Isaria japonica, and Torrubiella sp. The fruit bodies of Cordyceps in petri-dish cover were fixed by tape and put the lid on water agar plates to isolate these collected Cordyceps. The germinated spores were transferred from water agar to Potato dextrose agar(PDA) after six hours. Mycelial growth of C. nutans and C. militaris was the most successful on Hamada media and was also good on Complete media and PDA. Mannose as a carbon source was good for two species and Glutamic acid as a nitrogen source was satisfactory to C. militaris and Asparagine gave a good result to C. nutans. C. militaris and C. nutans showed similar mycelial growth rate on the media that contained thiamine-HCI, biotine or nicotinic acid as a vitamine. When conidia of C. nutans were inoculated to insects, mortality was high in Artogeia napi L, Hemiptera, Plutella xylostella and 50% in Orthoptera, 12% in Acantholyda posticalise M, but not Agelastica coerulea B. in Aphididae, C. nutans was collected from only Hemiptera in nature, but killing effect on other insects was proved. Mycelial growth and fruit-body formation were good on the media that consist of rice powder 5g, wheat flour 5g, water 100ml, but formed fruit-body was not complete stromata but a mass of conidia according to results of observing microscope.