• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.193-200
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• 1997

In order to manufacture the low salt and functional Kochujang, salt amount was reduced to 6% and chitosan was added to 0.25% to the Kochujang preparation. The contents of ash, moisture, crude fat and crude protein in Kochujang were not affected by the reduced salt concentration and chitosan addition. pH and titratable acidity were not significantly changed by the addition of chitosan. Ethanol content was higher in 6% salt Kochujang tan in 9% salt Kochujang and decreased by the addition of chitosan. Reducing sugar content was lower in 6% salt Kochujang than in 9% salt Kochujang and increased by chitosan addition. $\alpha$-Amylase activity was slightly inhibited by the addition of chitosan, however, $\beta$-amylase, acidic protease and neutral protease activities were not affected. Amino nitrogen and ammonia nitrogen contents were higher in 6% salt Kochujang than in 9% salt Kochujang, but ammonia nitrogen production was significantly decreased by chitosan addition. Also the growth of bacteria and yeasts were slightly inhibited by the addition of chitosan. From the above results we concluded that 0.25% chitosan was the good concentration to prepare the low salt and functional Kochujang.

• Journal of the Korean GEO-environmental Society
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• v.10 no.5
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• pp.27-32
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• 2009

This study evaluates tripolyphosphate's ability to treat AMD (Acid Mine Drainage). Based on the batch test results for reaction between tripolyphosphate and AMD obtained from Munkyung coal mine, $4.7{\times}10^{-3}$ mole is the optimum dosage of tripolyphosphate for AMD treatment. $Ca^{2+}$ concentration is decreased from $16.4mg/{\ell}$ to $5.6mg/{\ell}$, in other words, the removal rate of $Ca^{2+}$ is 65.9%. $Fe^{3+}$ concentration is decreased from $3.7mg/{\ell}$ to $0.02mg/{\ell}$, that is, the removal rate of $Fe^{3+}$ is 99.5%. $SO{_4}^{2-}$ concentration ranges from $526.8mg/{\ell}$ to $566.5mg/{\ell}$, which shows no obvious decrease. After dosing up tripolyphosphate, $Na^+$ concentration in AMD ranges from $549.8mg/{\ell}$ to $599.3mg/{\ell}$ and orthophosphate concentration in AMD ranges from $6.82mg/{\ell}$ to $7.60mg/{\ell}$. It was found that the precipitate in the order of amount is Apatite${\gg}{\beta}$-tricalcium phosphate > $Fe(OH)_3$ from SEM, XRF, XRD analyses. Consequently, the treatment by tripolyphosphate is effective in pH buffering and in the removal of $Ca^{2+}$ and $Fe^{3+}$.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.273-283
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• 1993

Addition of various acids or organic compounds to the electrolyte solution during the electrodeposition of $PbO_2$ on titanium madras substrate strongly affected performance of the deposited $PbO_2$ layer. Results of X-ray diffractometry ascertained that ${\beta}-PbO_2$ was deposited in acidic electrolyte. Among additives used in this experiment, $PbO_2$ with a high oxygen overvoltage was electrodeposited when sodium lauryl sulfate was added, and $PbO_2$ with a lower chlorine overvoltage was electrodeposited when polyethylene glycol was added to the electrolyte solution. The oxygen and chlorine overvoltage of $PbO_2$ was strongly dependent on the stirring provided during the electrodeposition experiment. It was observed by the SEM results that the $PbO_2$ grains deposited when stirring was not provided during the electrodeposition have larger than $PbO_2$ grains deposited by stirring. In the $PbO_2$ deposition under acidic electrolyte, the oxygen overvoltage increased with larger $PbO_2$ grains and the chlorine overvoltage decreased with smaller $PbO_2$ grains. The optimal current efficiency of $PbO_2$ in the presence of perchloric acid was observed at $Pb(NO_3)_2$ 560g/l, $65{\sim}70^{\circ}C$, and pH>1.

• Applied Biological Chemistry
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• v.14 no.3
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• pp.191-200
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• 1971

As a series on the soy-bean protein and their related substances 9 samples were collected from 9 places such as straws (Rice) to obtain bacterial strains which produce protease. From these samples total of 23 strains were isolated by the use of dilution pour plate method. For all isolated strains primary screening of productivity of protease was performed and useful straines with regard to protease productivities were identified. Optimum conditions for enzyme action of protease from isolates $D_9$, $F_{20}$ strains were pH 7.5 and $40^{\circ}C$. Chung-Kook-Jang is one of the characteristic foods in Korea made from soy-bean by fermentation. The chief bacterium is Bacillus subtilis and the chief change which takes place in soy-bean during fermentation is degradation of protein. Three kinds of Chung-Kook-Jang were prepared using three different strains of Bacillus natto, $D_9\;and\;F_{20}$ from isolated. Water soluble-N, TCA soluble-N, amino-N and peptide-N were measured about the steamed soybean, Chung-Kook-Jang prepared with three strains of bacteria. Water soluble-N decreased very largely in steamed soybean, but in Chung-Kook-Jang it increased to 85% of raw soy-bean.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.521-528
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• 1986

In this paper, proteolytic activity of the tissue extracts from the internal organs such as alimentary canal, pancreas, pyloric caeca, stomach, liver and spleen of mackerel, Scomber japonicus, and sardine, Sardinops melanosticta, was compared with each other under the optimum reaction condition. The proteinases distributed in alimentary canal, pancreas, pyloric caeca and spleen were active in alkaline pH range, but those in stomach were shown the activity in acid pH range, furthermore those in liver were exhibited the activity in acid, neutral and alkaline pH range. The proteinases distributed in the internal organs of both fish were stable at the heat treatment of $45^{\circ}C$ for 5 minutes. The proteinases from stomach and pyloric caeca of the two fish and those from pancreas of sardine were less stable than those from any other internal organs of both fish. Whereas the proteinases from spleen and neutral proteinases from liver were shown to be stable by the heat treatment at $55^{\circ}C$ for 5 minutes. The proteinases from pyloric caeca of both fish, and stomach, pancreas and spleen of mackerel were stable during the whole storage days at $5^{\circ}C$, but the other proteinases were slowly inactivated after 14 days of storage. The enzymes were seemed to be more stable in the storage at $-15^{\circ}C$ than at $5^{\circ}C$.

• Journal of the Korea Concrete Institute
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• v.29 no.1
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• pp.85-92
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• 2017

This study examines the characteristics of mortar mixed with various boron compounds. The adapted boron compounds, classified into acid, slightly alkaline and strongly alkaline with respect to the value of the pH are acid-based boron (AA), low-alkaline-based boron (AB), and high-alkaline-based boron (HB). The pH test, setting test and compressive strength test are performed to evaluate the physical and chemical properties of mortar, and SEM imaging is conducted to analyze the microstructure of mortar. The measured pH shows that the specimens mixed with boron compounds have lower pH than the basic mortar without boron and that loss of pH occurs according to time. The setting test reveals that the initial and final setting times of the specimens mixed with boron compounds occur later than the basic mortar, which disagrees slightly with the previous literature stating that the setting time can be shortened according to the alkalinity. From the compressive strength test and SEM imaging results, it is recommended to determine the optimal content of boron considering type and composition of the boron compounds.

• Journal of Korea Water Resources Association
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• v.39 no.12 s.173
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• pp.997-1012
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• 2006

We have presented a nonparametric stochastic approach for the SOI(Southern Oscillation Index) series that used nonlinear methodology called Nonlinear AutoRegressive(NAR) based on conditional kernel density function and CAFPE(Corrected Asymptotic Final Prediction Error) lag selection. The fitted linear AR model represents heteroscedasticity, and besides, a BDS(Brock - Dechert - Sheinkman) statistics is rejected. Hence, we applied NAR model to the SOI series. We can identify the lags 1, 2 and 4 are appropriate one, and estimated conditional mean function. There is no autocorrelation of residuals in the Portmanteau Test. However, the null hypothesis of normality and no heteroscedasticity is rejected in the Jarque-Bera Test and ARCH-LM Test, respectively. Moreover, the lag selection for conditional standard deviation function with CAFPE provides lags 3, 8 and 9. As the results of conditional standard deviation analysis, all I.I.D assumptions of the residuals are accepted. Particularly, the BDS statistics is accepted at the 95% and 99% significance level. Finally, we split the SOI set into a sample for estimating themodel and a sample for out-of-sample prediction, that is, we conduct the one-step ahead forecasts for the last 97 values (15%). The NAR model shows a MSEP of 0.5464 that is 7% lower than those of the linear model. Hence, the relevance of the NAR model may be proved in these results, and the nonparametric NAR model is encouraging rather than a linear one to reflect the nonlinearity of SOI series.

• KSBB Journal
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• v.14 no.4
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• pp.511-516
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• 1999

The effects of environmental and compositon factors, such as reaction time, metal ions, pH, agitation speed, the weight ratio of water to oil, and the weight of enzyme, on the hydrolysis of oils by Lipase-OF were investigated. In case of oils with low melting point, the optimum temperature of hydrolysis were the enzyme activity was maximum was 37$^{\circ}C$. However, when the melting temperature was higher than 4$0^{\circ}C$, the optimum temperature was around the fusion temperature. The activity of Lipase-OF decreased very rapidly with increase of temperature in the range of higher than 45$^{\circ}C$ and the activity perished above $65^{\circ}C$. The effect of agitation speed was investigated from 150 to 650 rpm. The hydrolysis of oils increased as the agitation speed increased up to 350 rpm, but it did not increase any more above 350 rpm. The weight ratio of water to oil was changed from 1 : 9 to 9 : 1 for the investigation of the effect on the hydrolusis. The weight ratio for maximum hydrolysis was 1 : 1. $Ca^{2+}\;and\;Mg^{2+}$ among various metal ions had some effect on the stimulation of hydrolysis. The optimum concentration of the ions was about 100ppm at which the hydrolysis increased, compared with that of distilled water, by 2 to 3%. The Optimum pH of Lipase-OF was 7. The hydrolysis decreased as the pH decreased as the pH decreased and also decreased as the pH increased. The content of enzyme affected the hydrolysis of oil. The hydrolysis increased with the content of Lipase-OF in the range of less than 0.013 wt% of substrate. However, the increase of hydrolysis with the content of Lipase-OF ceased above 0.013 wt%. The experiments investigating the effect of environmental and composition factors on the hydrolysis of oils showed that the optimum temperature was 37$^{\circ}C$, the pH 7, the concentration of $Ca^{2+}\;or\;Mg^{2+}$ 100 ppm, the agitation speed 350 rpm, the weight ratio of water to oil 1 : 1, and the content of Lipase-OF 0.013 wt% of substrate.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.141-146
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• 2007

The present paper describes a procedure for separation, preconcentration and determination of trace amount of copper in natural water samples by using 2-mercaptobenzimidazol as the complexing agent. The proposed method is based on the surfactant aggregation formed on γ-alumina by mixing sodium dodecyl sulfate and γ-alumina in water; 2-mercaptobenzimidazol was incorporated into inner hydrophobic part of produced ad-micelles in acidic media to produce an assemble suitable for preconcentration and determination of copper ion. Optimum experimental conditions for adsorption of μg/ml levels of copper ions from aqueous solution by the adsorbent have been reported. The copper ions were quantitively adsorbed by the sorbent over the pH range of 7.1-8.0 and were quantitatively desorbed afterward by using sulfosalycilic acid as the eluent. The determination of copper was not interfered in the presence of common metal ions. The procedure was applied for analysis of river water sample. Relative standard deviation was found to be 4.91%.

• Journal of the Korean Applied Science and Technology
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• v.34 no.1
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• pp.58-65
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• 2017

Fluidized bed gasification is technically and economically proven technology, which shows the high possibility of realization and commercialization. However, in Korea, development of FBG to the commercial scale for power generation and industry is mainly blocked by the fact that there is no experience of design, troubleshooting and operation of even pilot scale fluidized bed gasifier. In this study, a $3MW_{th}$ circulating fluidized bed(CFB) was newly developed for biomass gasification. The fluidized bed was mainly composed of circulating and bubbling fluidized reactors integrating in-situ tar removal step in the system. For cleaning of the tar and acid gas in the product gas, the sequential gas cleaning process comprised of a ceramic filter, rapid quencher and wet scrubber was adopted. Effect of equivalence ratio was investigated to find the optimal operating conditions for the $3MW_{th}$ integrated system of fluidized bed gasification.