• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.6
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• pp.780-787
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• 2019

As a carbon-free, green growth alternative, internal and external interest in hydrogen energy and technology is growing. Hydrogen was added to co-axial methane, methane-propane, and methane-propane-ethane diffusion flames, which are the main ingredients of LNG, to evaluate its effect on flame formation and combustion products. The variation in combustion products produced by adding hydrogen gradually to diffusion pyrolysis at room temperature and normal pressure conditions was observed experimentally by using a gas analyzer, and the shape of diffusion pyrolysis was observed step by step using a digital camera. The experimental results showed that the production volume of nitrogen oxides tended to increase and became close to linear as hydrogen was added to the diffusion pyrotechnic. This is because the relatively high temperature of heat insulation and fast combustion speed of hydrogen facilitated the production of thermal NOx. On the other hand, CO2 production tended to decrease as hydrogen was added to reduce the overall carbon ratio contained in the mixed diffusion flame of methane, methane-propane, and methane-ethane-propane. This means that the mixed fuel use of LNG-hydrogen in ships may potentially reduce emissions of CO2, a greenhouse gas.

• Korean Journal of Materials Research
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• v.9 no.4
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• pp.349-354
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• 1999

The temperature dependences of the Hall coefficient, carrier mobility, electrical resistivity, Seebeck coefficient, thermal conductivity, and figure-of-merit of the undoped and $CdI_2$-doped 90% $Bi_2Te_3-10% Bi_2Se_3$, single crystals, grown by the Bridgman method, have been characterized at temperatures ranging from 77K to 600K. The saturated carrier concentration and degenerate temperature of the undoped 90% $Bi_2Te_3-10% Bi_2Se_3$ single crystal are $5.85\times10_{18}cm^{-3}$ and 127K, respectively. The scattering parameter of the 90% $Bi_2Te_3-10% Bi_2Se_3$ single crystal is determined to b -0.23, and the electron mobility to hole mobility ratio ($\mu_e/\mu_h)$ is 1.45. The bandgap energy at 0K of the 90% <$Bi_2Te_3-10% Bi_2Se_3$ single crystal is 0.200 eV. Adding $CdI_2$as a donor dopant, a maximum figure-of-merit of $3.2\times10^{-3}/K$$CdI_2$-doped specimen.

• Journal of the Korean Chemical Society
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• v.26 no.3
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• pp.160-164
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• 1982

A guanidinium salt of $[U(PW_{11}O_{39})_2]^{10-}$, the solubility of which is adequate for crystal growing, has been synthesized. Using this salt or potassium salt, we have measured the stability of $[U(PW_{11}O_{39})_2]^{10-}$as a function of pH of the solution and found that the anion is stable for the pH range 3~7. We have developed a colorimetric method for determining the concentration of $U^{4+}$. In this method$PW_{11}O_{39}^{7-}$ is added to$U^{4+}$ in such a quantity that the mole ratio $PW_{11}O_{39}^{7-}/ U^{4+}$exceeds 2 and the intensity of the 22.7kK band (${\varepsilon}$1030 M-1cm-1) is measured. In order to develop a continuous method to recover uranium, we have determined the amount of recoverd$PW_{11}O_{39}^{7-}$ after decomposing $[U(PW_{11}O_{39})_2]^{10}$- by adding either a base or an oxidizing agent. The percentage of $PW_{11}O_{39}^{7-}$recovered was approximately 70% when a base was used and approximately 80% when$K_2S_2O_8$ was used. A colorimetric method for determining $PW_{11}O_{39}^{7-}$ has also been developed.

• Culinary science and hospitality research
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• v.16 no.5
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• pp.277-286
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• 2010

This study examines the quality characteristics of garaedduk with roasted rice bran in addition of the control at 10%, 20%, 30% & 40% and to measure the mechanical and sensory quality characteristics in order to show the optimum addition ratio and production condition. The result of adding roasted rice bran with 10% up to 40% in all research groups are as follows; First of all, the moisture content was decreased and the "L" score which represents the brightness of garaedduk showed 68.86 in control which was non supplemented garaedduk. L-value decreased. However, a-value increased significantly and b-value increased except in control group. In the experiment on hadness, it showed 0.69 in control group and it showed 0.94 in garaedduk with 10% of roasted rice bran. Also, there was significant difference in hardness depending on the amount of roasted rice bran and storage period. In the experiment on the sensory evaluation of color and flavor in panel test, all groups showed higher scores than control group. Moreover, there was significant taste difference depending on the amount of roasted rice bran. As a test result, the overall acceptability by sensory evaluation was observed as 30%>10%>20%>40%> in the group added with roasted rice bran.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.1025-1029
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• 2008

Fresh green tea leaf extracts were prepared by different enzyme treatment conditions, such as concentration, treating time and treating temperature using complex enzyme, Rapidase TF, and then extracted for 30 min at $80^{\circ}C$ to investigate their physicochemical properties. The results showed that free sugar content in every sample tended to increase, especially glucose content was increased up to 7.25 times compared to the control. Total amino acid was barely affected by the enzyme treatment and caffeine content was increased with reaction temperature. Total polyphenol and total catechin content was increased according to the amount of enzyme added and reaction temperature. Regardless of enzyme treatment conditions, composition of catechins were epigallocatechin, epicatechin, epicatechin gallate and epigallocatechin gallate by descending order of the content. Gallic acid content increased up to 0.04% and $45^{\circ}C$ with no further significant changes thereafter. From the results above, we could conclude that a simple and new method to extract green tea materials directly from fresh green tea leaves with improved extract ratio may be introduced by adding $0.08{\sim}0.1%$ of Rapidase TF to heat treated fresh green tea leaves and keeping temperature at $37{\sim}45^{\circ}C$ for $180{\sim}240\;min$ in order to skip existing complicated procedures.

• Journal of the Korean GEO-environmental Society
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• v.15 no.11
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• pp.61-66
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• 2014

The various recycling methods of mixed coal ash have been developed considerably and it's recycling quantity has been increased. However, the more relatively finer grain content of coal ash in ash pond is increased the more it's quantity is increased in recycling as products for drainage in soft ground etc. Accordingly, the geotechnical properties of mixed coal ash in ash pond would be inferior and it's recycling rate should reach the limitations in increase. In this study, to recycle mixed coal ash contained fine grain in considerably amount as products for strength, etc. By adding binder to it and manifesting, it's compressive strength is stronger than the criteria, these are suggested; 1) the variety of compressive strength test performed on mixed coal ash of various grain distributions as main material, 2) the kind of binder, it's mixing quantity and the optimum content rate range of fine grain coal ash that the compressive strength stronger than a certain compressive strength is manifested. Cement is more excellent than quicklime as binder in manifesting stronger compressive strength and the sieve type to sort it is #40 sieve in order to recycle all mixed coal ash in ash pond efficiently as products for drainage as well as products for strength, etc. And, it could increase insufficient compressive strength remarkably that content of pure sand is more in the rate as pure sand and the part of mixed coal ash in ash pond to pass through #40 sieve is mixed in the ratio of 2 to 8.

• Journal of Aquaculture
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• v.9 no.4
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• pp.353-361
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• 1996

The objective of this study was to investigate the essential fatty acids requirement and its optimal level in dietary for young of tiger puffer. The young puffer fish used in feeding trial were average body weight 3.45g. Fish were randomly divided into 11 groups containing 30 fish each in 200 ${\ell}$ tank and reared for 8 weeks at ambient temperature. In basal diets, defatted squid meal, casein-Na and activated gluten were used as the dietary protein source, dextrin and ${\alpha}$-starch (gelatinized starch) as the digestible carbohydrate source and beef tallow as the lipid source. Five fatty acids added to diet were linoleic acid (LNA), linolenic acid (LNA), eicosapentaenoic acid (EPA) ,docos-ahexaenoic acid (DHA) and n-3 HUFA. Among that, the supplement of LA and LNA were $1\%$ of total composition of diet, respectively, and EPA, DHA and n-3 HUFA ranged from $0.3\~1\%$ level. Growth and feed efficiency were measured to the interval of 2 weeks, and analyzed fatty acids composition of diet and liver by GCL. As a result of 8 weeks experiment, predominant growth were shown in $0.5\~1\%$ n-3 HUFA and $0.5\%$ DHA than others (P<0.05). In comparison of efficiency among EPA, DHA and n-3 HUFA groups, the most results were revealed in n-3 HUFA and the least in EPA. The adding effect was shown in EPA by increasing the fatty acids content from 0.5 to $1\%$ in diet. However, sudden decline and steady state in growth were observed in $1\%$ DHA and $1\%$ n-3 HUFA, respectively. The feeding efficiency and protein efficiency ratio were high in n-3 HUFA groups and $0.5\%$ DHA. Consequently, it is assumed that young puffer requires n-3 HUEA both EPA and DHA as essential fatty acids. The optimal content in diets are about $0.5\%$ of HUFA or DHA.

• Journal of Bio-Environment Control
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• v.5 no.1
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• pp.7-14
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• 1996

This experiment was carried out to investigate the growth and yield responses of hydroponically grown tomato as affected by the different substrates using perlite and mixtures with perlite. Substrates used in this experiment were perlite (fine and coarse granule), peatmoss, rice hull and carbonized rice hull. The results obtained were as follows ; The best results in terms of total fruit yield and average fruit weight obtained in the single treatment of perlite, followed by perlite mixture with rice hull and carbonized rice hull. Leaf area was also higher in the plots of perlite mixture and optimum mixing ratio of perlite, peatmoss and carbonized rice hull was determined as 5:3:2 by volume. The more the rice hull was added to the mixed substrates, the less in fruit production was observed. However, adding perlite to other substrates brought higher fruit yield. Single treatment of rice hull showed the lowest fruit yield but enhanced in soluble solids contents over 6.0 $^{\circ}$Brix at each cluster.

• Journal of Mushroom
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• v.13 no.3
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• pp.262-265
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• 2015

This study was carried out to investigated optimum mixing ratio of Korean cultivation Salvia miltiorrhiza for production of functional oyster mushroom. Mycerial growth was slow at addition of Salvia miltiorrhiza, and significant difference by increase of Salvia miltiorrhiza. Yields of fruiting body show the highest to 139.5 g/850 ml of medium which are addition 5 g/bottle of Salvia miltiorrhiza but rapid decrease by increase of Salvia miltiorrhiza. Diameter of pileus and thick of stipes were higher at addition Salvia miltiorrhiza than those of the controls. Thick of pileus and length of stipes were the highest at addition 30g, and 20 g and 30 g of Salvia miltiorrhiza. The L value of stipes were the highest at addition 20 g and 50 g of Salvia miltiorrhiza and the L value of pileus were the highest at addition 30 g of Salvia miltiorrhiza, but there was no significant difference in the a-value and the b-value.

• Journal of Life Science
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• v.14 no.5
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• pp.868-873
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• 2004

The efficient fermentative production of L-threonine fermentation was achieved by using Escherichia coli MT201, transformed a plasmid carrying pyruvate carboxylase gene. It is an attempt to supply oxaloacetate to the L-threonine biosynthetic pathway. In order to improve the L-threonine productivity of E. coli MT201, a plasmid pPYC which is an expression vector of the pyruvate carboxylase gene of Coryne-bacterium glutamicum, was introduced. When E. coli MT/pPYC was incubated with medium containing only glucose as a carbon source, both the cell growth and L-threonine production were reduced, compared to the results from fermentation of E. coli MT201. In order to circumvent this effect, we attempted the addition of a mixed carbon source, composed of glucose and sodium citrate at a ratio of 1.5:3.5. It was shown that L-threonine production and cell growth (OD660) with E. coli MT/pPYC reached up to 75.7 g/l and 48, respectively, at incubation for 75 hr under fed-batch fermentation conditions. It is assumed that overproduction of L-threonine by anaplerotic pathway leads unbalance of TCA cycle and sodium citrate might playa role to recover normal TCA cycle.