• Proceedings of the KSEEG Conference
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• 2004.12a
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• pp.9-28
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• 2004

Concern about arsenic is increasing throughout the world, including areas of the United States. Elevated levels of arsenic above current drinking-water regulations in ground and surface water can be the result of purely natural phenomena, but often are due to anthropogenic activities, such as mining and agriculture. The current study correlates arsenic speciation in acid mine drainage and mining influenced water with the important water-chemistry properties Eh, pH, and iron(III) concentration. The results show that arsenic speciation is generally in equilibrium with iron chemistry in low pH AMD, which is often not the case in other natural-water matrices. High pH mine waters and groundwater do not 짐ways hold to the redox predictions as well as low pH AMD samples. The oxidation and precipitation of oxyhydroxides depletes iron from some systems, and this also affects arsenite and arsenate concentrations differently through sorption processes.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.295-299
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• 1987

Mungbean Lipoxygenase was purified by ammonium sulfate fractionation, DEAE-sephacel column chromatography and sephadex G-200 gel filtration. The specific activity of pfurified enzyme was 23.4U/mg protein and the yield was 12%. Optimal activity of the enzyme was observed at pH 8.4 and the enzyme had Km value of 0.25mM for linoleic acid. The enzyme was stable in the range of pH 5.0-7.0 and at temperature below $50^{\circ}C$. The enzyme activity was inhibited by antioxidants such as nordihydroguiaretic arid and chelating agents.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.857-864
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• 2003

In a trial involving 120 pigs, the effects of transport time on blood profile and meat quality in pigs were investigated. One group of 60 animals was subjected to 20 min and the others to 2 h transport time, and held in lairage for 1 h 30 min. There was not significantly different in the carcass weight, backfat thickness and carcass grade between groups. Cortisol and lactic dehydrogenase(LDH) concentrations were significantly(P〈0.05) higher in the group transported for 2 h compared with the group transported for 20 min. There was not significantly different(P〉0.05) in meat quality(pH$_1$, pH$_{u}$, drip loss, cooking loss, hardness, CIE L$^{*}$, a$^{*}$, b$^{*}$ and NPPC) and skin damage of pork carcass between groups. These results imply that the stress could be affected by transport time in transit without meat quality.

• Bulletin of the Korean Mathematical Society
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• v.55 no.1
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• pp.187-204
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• 2018

Let $R={\bigoplus}_{{\alpha}{\in}{\Gamma}}\;R_{\alpha}$ be a graded integral domain, H be the set of nonzero homogeneous elements of R, and ${\star}$ be a semistar operation on R. The purpose of this paper is to study the properties of $quasi-Pr{\ddot{u}}fer$ and UMt-domains of graded integral domains. For this reason we study the graded analogue of ${\star}-quasi-Pr{\ddot{u}}fer$ domains called $gr-{\star}-quasi-Pr{\ddot{u}}fer$ domains. We study several ring-theoretic properties of $gr-{\star}-quasi-Pr{\ddot{u}}fer$ domains. As an application we give new characterizations of UMt-domains. In particular it is shown that R is a $gr-t-quasi-Pr{\ddot{u}}fer$ domain if and only if R is a UMt-domain if and only if RP is a $quasi-Pr{\ddot{u}}fer$ domain for each homogeneous maximal t-ideal P of R. We also show that R is a UMt-domain if and only if H is a t-splitting set in R[X] if and only if each prime t-ideal Q in R[X] such that $Q{\cap}H ={\emptyset}$ is a maximal t-ideal.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.251-259
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• 1990

Asp. usumii IAM 2185 was selected as a strain producing the powerful raw starch digesting glucoamylase. The optimum initial pH, the optimum temperature and the optimum cultural time for the enzyme production on wheat bran medium were pH 6-8,25-$30^{\circ}C$ and 72 hrs, respectively. The addition of ammonium nitrate and albumin on wheat bran medium, respectively, increase slightly the enzyme production. The enzyme was purified by ammonium sulfate fractionation, CM-cellulose and DEAE-cellulose column chromatography. The specific activity of the purified enzyme was 34.3 U/mg protein and the yield of enzyme activity was 10.3%. The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 67,000 by SDS polyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pR 3.7. The optimum temperature and optimum pH were $60^{\circ}C$and pH 3.0 and the purified enzyme was stable in the pH range of 1.0-11.0. The purified enzyme was stable below $50^{\circ}C$ and its thermostability was greatly increased by the addition of $Ca^{2+}$. The purified enzyme showed a high hydrolysis rate on various raw starches such as corn, rice, yam, arrow root, sweet potato and glutinous rice.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.6
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• pp.521-531
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• 2014

This paper is a study for behaviour of cavern type anchorage tunnels for suspension bridges with cable tension. Anchorage behaviour, design method for anchorage, and failure surface angle, ${\delta}$ are analyzed by comparing numerical analysis results and ultimate pullout capacities($P_u$) using bilinear corelation equation. Results show that design depths for cavern type anchorage tunnels are easily checked with linear relationships for $P/{\gamma}/H$ vs. displacement and $P_u/{\gamma}/H$ vs. H/b. The analysis results of maximum shear strain distribution and plastic status show that failure shapes are closer to circular arc model than soil cone model which frequently used. To an easy calculation of the ultimate pullout capacity, we propose a simple bilinear failure model in this study. The calculated ultimate pullout capacities from the proposed bilinear corelation equation using two failure angles results are similar to the ultimate pullout capacities from numerical analysis.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.325-328
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• 2000

The effects of DO and pH on the mass production of pullulan with high-molecular weight from A. pullulans ATCC 42023 were evaluated. The maximum pullulan production yield (51%) was obtained at pH non control (initial pH 6.5) and DO control (above 50%) condition. The pullulan degrading enzyme was activated when the pH of broth reached lower than 5.0 and portion of low molecular weight pullulan was increased. The formation of a black pigment was observed at the initial stationary phase, 40hr of fermentation. Therefore, the fermentation should be carried out in pH non control and DO control condition and harvested before reaching stationary phase around 40h for the production of high molecular weight pullulan.

• Journal of Aquaculture
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• v.12 no.2
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• pp.155-161
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• 1999

In order to obtain the basic information for seeding production of Echiuroid worm, Urechis unicinctus, the influence of pH and salinity on egg development was investigated. Mature adult of U. unicinctus were collected at the Diving Cooperation of Yosu in Korea and reared during 5 weeks. We carried out the artificial insemination in the laboratory on Dec. 29, 1998, and reared the embryo under different pH and salinity. Treatments were carried out with different pH(4~10) and salinity($0~45\textperthousand$). Embryos in pH 4, salinity $0\textperthousand$, $10\textperthousand$, $40\textperthousand$ and $45\textperthousand$ tanks did not develope after fertilization and became deformed or dead, before swimming embryo. In these pH and salinity conditions, deformation rate of embryo was high at 8-cell stage and 16-cell stage. But embryos in pH 5~10, salinity $20~35\textperthousand$ tanks developed into swimming embryo stage. These result indicate that an echiuran inhabits in both intertidal and subtidal mudflates. After fertilization, sixteen-cell stage took 5.3~5.6 hours in pH 5~10 tanks, and 5.1~5.8 hours in $20~35\textperthousand$ tanks. And swimming embryo took 13.3~ 14.1 hours in all conditions. The desirable pH and salinity for egg development were 7~8 and $30\textperthousand$, respectively.

• Journal of Food Hygiene and Safety
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• v.8 no.2
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• pp.91-95
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• 1993

The growth of Bifidobacterium and Lactobacillus isolated from human interstinal bacteria were induced by water extract and U-step extract of soybean and carrot and the pH of these bacteria-cultured media were decreased. The increasing growth rates of these bacteria are related to the decrease of the pH of these bacteria-cultured media. When human intestinal flora as starter were inoculated into the medium containing water extract of soybean and carrot. the growth of lactic bacteria were also induced and the pH of the media were decreased. By measuring the pH of the media which were inoculated and cultured intestinal bacteria as a starter, it is possible to determine whether the food are the growth factors of intestinal lactic acid bacteria or not. By this method, the food which decreased pH of the medium were soybean, turnip, carrot. leek, garic, dropwork, wonnwood and onion. 'These foods may induce lactic acid bacteria in human in1estlne.

• Journal of the Korean Mathematical Society
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• v.55 no.6
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• pp.1337-1358
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• 2018

In this paper, we study the solvability of the nonlinear Dirichlet problem with sum of the operators of independent non standard growths $$-div\({\mid}{\nabla}u{\mid}^{p_1(x)-2}{\nabla}u\)-\sum\limits^n_{i=1}D_i\({\mid}u{\mid}^{p_0(x)-2}D_iu\)+c(x,u)=h(x),\;{\in}{\Omega}$$ in a bounded domain ${\Omega}{\subset}{\mathbb{R}}^n$. Here, one of the operators in the sum is monotone and the other is weakly compact. We obtain sufficient conditions and show the existence of weak solutions of the considered problem by using monotonicity and compactness methods together.