• Membrane Journal
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• v.28 no.3
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• pp.157-168
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• 2018

Potassium tannate (TA-K), which is prepared by base treatment of the bio-renewable tannic acid (TA), was evaluated for its potential application as a draw solute for water purification by forward osmosis. The forward osmosis and recovery properties of TA-K were systematically investigated. In the application of forward osmosis through the active layer facing feed solution (AL-FS) method, the water flux of TA-K draw solution was significantly higher than that of the TA draw solution, while that of the latter was not identified. At a low concentration of 100 mM, the osmotic pressure (1,135 mOsmol/kg) of the TA-K draw solution was approximately 6.5 times that (173 mOsmol/kg) of the NaCl draw solution. Furthermore, the water flux and specific salt flux (6.14 LMH, 1.26 g/L) of the TA-K draw solution at 100 mM were approximately 2.5 and 0.5 times those of the NaCl draw solution (2.46 LMH, 2.63 g/L) at the same concentration, respectively. For reuse, TA-K was precipitated by using a metal ion and recovered through membrane filtration. This study demonstrates the applicability of a phytochemical material as a draw solute for forward osmosis.

• Corrosion Science and Technology
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• v.14 no.5
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• pp.218-225
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• 2015

The electrochemical behaviors of various metals with and without diamond-like-carbon (DLC) coating in 3.5 wt% NaCl solution were investigated. The effect of hydrodynamic conditions was focused by employing a rotating disc electrode (RDE). The experimental results showed that each bare metal had a more positive corrosion potential and a higher corrosion rate due to enhanced oxygen transport at the higher rotating speed of the RDE. DLC coating caused a substantial increase in the corrosion resistance of all metals studied. However, localized corrosion was still found in the DLC-coated metal at sites where deposition defects existed. Surface morphology examination was performed after the electrochemical test to confirm the roles of hydrodynamic conditions and DLC coating.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.367-376
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• 1997

Vibrio vulnificus is a gram-negative, halophilic, oxidase-positive, lactose-positive, motile, rod shaped bacterium that has been associated with primary septicemia and wound infection. Elucidating the growth and survival of V. vulnificus in ecological conditions is of great importance to develop sanitary measure against this microorganism. Thus we simulated the ecological conditions and evaluated the effect. About $10^5\;CFU/ml$ of V. vulnificus was inoculated to fresh water, brackish water $(1\%\;NaCl)$, sea water $(3\%\;NaCl)$, and bottom deposit solution. The same concentration of V. vulnificus was also inoculated to distilled water, $1\%\;NaCl$ solution and $3\%\;NaCl$ solution as controls. These were stored at 4, 15 and $25^{\circ}C$, respectively and were used to assess the effects of temperature and salinity on the survival of V. vulnificus. In fresh water V. vulnificus could not survive regardless of storage temperature. In case of brackish water and sea water survival time of V. vulnificus was the longest at $25^{\circ}C$, and the number of V. vulnificus was decreased most rapidly at $4^{\circ}C$. V. vulnificus survived longer in brackish water than in any other conditions. In bottom deposit solution containing brackish water, the survival time of V. vulnificus was longer and the rate of decline was slower than that in brackish water. These results indicate that both biological and physicochemical factors such as temperature and salinity could affect survival of V. vulnificus. V. vulnificus, damaged in normal fresh water, did not grow on TCBS agar of selective plating medium but grew on BHI agar plate; However, V. vulnificus was recovered by addition of salt and nutrient materials.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.51-56
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• 1994

Development for extraction method of sea tangle was investigated with addition of sucrose, NaCl, EDTA-2Na, SHMP, and hydrolysis with commercial polysaccharide hydrolyzing enzymes. The total solids and protein yields were significantly increased by enzymatic hydrolysis or addition of NaCl and EDTA-2Na during boiling. The extract prepared by enzymatic hydrolysis followed by 2 hrs of boiling in 1.5% NaCl solution was significantly improved in solids and protein yield from 24.1% and 13.9% of 2 hrs of water boiling to 44.6% and 32.2%, respectively. The combined method increased the amino-nitrogen content but reduced the turbidity and viscosity. Extracts with a high intensity of total and seaweed-like taste as revealed by sensory evalution were obtained by combined method.

• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.141-148
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• 1995

Fatigue tests were carried out by a rotary bending testing machine of cantilever type. M.E.F.(ferrite encapsulated islands of martensite) materials were made by a series of heat treatment from a low carbon steel(SM 20 C). The fatigue tests were conducted at stress levels of 302 MPa and with frequencies of 25Hz, 2.5 Hz and 0.5 Hz in 3% NaCl solution. The fatigue strength increased with frequency got higher. The microcracks and corrosion pits were generated at the boundary between the matrix and the 2nd phase. The cracks generated by the corrosion pits were coalesced with the pits around the notch and became the initial crack. The $N_i/N_f$ ratio increased as the frequency and stress level decreased. The interference phenomenon increased with stress level and frequency gots higher. The crack propagation rate was delayed as the stress level lowers and the frequency gets higher, however, the range of the stress intensity factor depended only on a stress level.

• Journal of Aquaculture
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• v.10 no.3
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• pp.273-279
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• 1997

Condition for fresh storage of tiger puffer in the liquid state were investigated in several experiments. When marine fish ringer solution and 1% NaCl were used as the diluent for the short-term preservation method, spermatozoa activity index (SAI) and survival rate showed the best result among the various diluents tested. The dilution rate for the shortterm preservation of spermatozoa was suitable between 3 and 5 times with the 1% NaCi diluent. The appropriate range of temperature for the short-term preservation showed between 0 and $5^{\circ}C$. In order to keep high SAI and survival rate of spermatozoa, antibiotic addition (800 ppm neomycin) could be suggested. These results indicated that the short-term preservation method could be employed in tiger puffer spermatozoa.

• Applied Biological Chemistry
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• v.34 no.3
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• pp.213-218
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• 1991

Addition of salts or their mixtures and microwave heating were studies for their effects on Kakdugi fermentation. The Kakdugi, a Korean fermented Chinese radish, were prepared by salting in 15% NaCl solution and fermented at $25^{\circ}C$. From the results, a first order reaction relationship was found between salt permeated into the radish and time during brining in $5{\sim}10%$ NaCl solution. Addition of 0.05M KCl into 15% NaCl brining solution or microwave heating of salted radish for 3 minutes showed a little decreasing effect on Kakdugi fermentation rate while beating for 1 or 2 minuted resulted a rather increase. When three different salt mixtures in the concentration range of $0.001{\sim}0.01\;M$ were added into half fermented Kakdugi(appr. pH 4.4), the fermentation was greatly controlled based on pH change. Among the salt mixtures, mixture III$(Na_2HPO_4,\;Na_2PO_4,\;NaNO_2,\;Ca\;EDTA,\;Sod.\;citrate)$ showed a most significant effect where the time required to reach pH 4.0 after addition was extended by more than 6 folds when it was compared to the control method.

• Journal of the Korean Ceramic Society
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• v.25 no.1
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• pp.66-72
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• 1988

The effect of salts on the formation of ${\alpha}$-hemihydrated gypsum at boiling temperature under atmospheric pressure was studied by the solubility measurement method, and the formation of ${\alpha}$-hemihydrated gypsum from by-product gypsum of phosphoric acid process in the salts solution were investigated. The order of catalytic effect of salt on the formation of ${\alpha}$-hemihydrated gypsum are as follows: NH4Cl>NaCl>NaNO3. In the salts solution of sodium nitrate, sodium chloride, and ammonium chloride, prismatic ${\alpha}$-hemihydrated gypsum was obtained and the crystal form was converted to needle form in complex solution with sulfuric acid. The P2O5 content in gypsum was largely decreased in this atmosphoric solution process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.7
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• pp.589-593
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• 2011

[ $SnO_2$ ]nano powders were prepared by solution reduction method using tin chloride($SnCl_2{\cdot}2H_2O$), hydrazine($N_2H_4$) and NaOH. The $SnO_2$ thick films for gas sensors were fabricated by screen printing method on alumina substrates and annealed at $300^{\circ}C$ in air, respectively. XRD patterns of the $SnO_2$ nano powders showed the tetragonal structure with (110) dominant orientation. The particle size of $SnO_2$ nano powders at the ratio of $SnCl_2:N_2H_4$+NaOH= 1:6 was about 60 nm. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box. Sensitivity of $SnO_2$ gas sensor to 5 ppm $CH_4$gas and 5 ppm $CH_3CH_2CH_3$ gas was investigated for various $SnCl_2:N_2H_4$+NaOH proportion. The highest sensitivity to $CH_4$ gas and $CH_3CH_2CH_3$ gas of $SnO_2$ sensors was observed at the $SnCl_2:N_2H_4$+NaOH= 1:8 and $SnCl_2:N_2H_4$+NaOH= 1:6, respectively. Response and recovery times of $SnO_2$ gas sensors prepared by $SnCl_2:N_2H_4$+NaOH= 1:6 was about 40 s and 30 s, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.5
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• pp.772-778
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• 2001

In this study, corrosion fatigue characteristics of 12Cr alloy steel were investigated in 3.5wt.% NaCl solution of 150$^{\circ}C$ and 4.5bar. Behavior of corrosion fatigue cracks was measured by the indirect compliance method and compared with the results in distilled water and in air. 1) 12Cr alloy steel was susceptible to temperature. Its susceptibility was increased as the temperature was increased. 2) The crack growth characteristics of 12Cr alloy steel in distilled water were similar to 3.5wt.% NaCl solution. 3) The temperature of solution affects to the crack growth characteristics of 12Cr alloy steel. In corrosion solutions of 4.5bar, 150$^{\circ}C$, fracture surfaces of corrosion fatigue crack growth at a/W=0.3 was showed the trans-granular fracture suface. As the crack grew up, it was changed to inter-granular type. In condition of high temperature, The crack growth behaviors of 12Cr alloy steel were remarkable.