• Bulletin of the Korean Chemical Society
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• v.3 no.1
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• pp.23-30
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• 1982

For the study of transport phenomena of an aqueous NaCl solution through a cuprophane membrane, a new apparatus was constructed. The volumc flow rate Q, the permeability coefficient U, and the permeability constant K were measured or determined by using this apparatus. The experimental temperature range was 5 to $35^{\circ}C$, and the applied pressure increments were 10 to 40 psi. By assuming that the cuprophane membrane is composed of n parallel cylindrical capillaries of circular cross-section and that the flow of the solution through the capillaries follows the Poiseulle law, the mean radius r of the capillaries and the number n of the latter in the membrane were evaluated. By using a reasonable assumption concerning the radius ${\eta}'$ of the species diffusing through the membrane, it was concluded that the contribution of the diffusive flow to the total flow rate Q is less than 10%. Thus, the Q was treated as the rate due to the viscous flow, and the viscosity ${\eta}_m$ of the solution in the membrane phase was evaluted, and it was found that ηm is nearly equal to ${\eta}_b$, the bulk viscosity of the solution. From this fact, it was concluded that in the capillaries, no change occurs in the physical state of the NaCl solution. The value of ( = 4.27 kcal/mole) and ${\Delta}Sm^{\neq}$(4.28 eu) were obtained for the viscous flow. A possible explanation was given.

• Korean Journal of Environment and Ecology
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• v.12 no.1
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• pp.9-13
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• 1998

Because Lysimachia mauritiana is not able to maintain the seed viablity for a long time, it has difficulties in using for the ornamental plants or landscape gardening. This study was conducted to elucidate the optimal germination conditions of Lysimachia mauritiana seeds. The germination rate of the seeds was higer in light condition than in dark one. In experment determining the proper germination temperature, the germination rates were 2.2%, 96.9% and 91.2% under 35$\circ $C, 25$\circ $C, and 20$\circ $C, respectively in light condition. The approprate temperature for the germination was 25$\circ $C in light. The decreases of germination rate with the increase of the preservation periods was able to recover by priming pretreated with NaCl solution and KNO$_{3}$ + K$_{3}$H$_{2}$PO mixed solutions. When the storage period was 300 days, the germination rate was 75% without priming treatments. But the seeds primed with NaCl 0.1M and KNO$_{3}$ + K$_{3}$H$_{2}$PO mixed solutions 0.1M, showed germination rate above 90%. T$_{50}$ also was shorten from 5.25 without priming to 3.78 with NaCl 0.1M. Seed priming may induce earlier sprouts and increase germination rate of long-preserved seeds of native wild plants.

• The Korean Journal of Food And Nutrition
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• v.9 no.3
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• pp.319-324
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• 1996

The functional properties of protein recovered from red crab (Chitinonecetes opiiie) processing in water (RCP) were examined and compared with those of soybean protein isolate at pH 2~10 in water and NaCl solu5ion. The solubilities of RCP and SPI were miniumu at pH 4, the isoelectric point and increased significantly at lower or higher than pH 4. Solubilities in NaCl solution for both proteins decreased with incr NaCl concentration increase at all pH ranges. Emulsion capacity for both proteins was also minimum at pH 4 and increased as protein concentration increased from 2 to 6%. Emulsion capacity of RCP was higher than these of SPI at pH 6∼10 and all protein concentrations. Emulsion stability showed a similar trend to that of emulsion capacity. RCP had higher oft absorption capacity and lower water absorption capacity than SPI.

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1757-1762
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• 2006

A solvent sublation using salphen as a ligand was studied and applied for the determination of trace Ni(II), Co(II) and Cu(II) in water samples. The fundamental study was investigated by a solvent extraction process because the solvent sublation was done by extracting the floated analytes into an organic solvent from the aqueous solution. The salphen complexes of Ni(II), Co(II) and Cu(II) ions were formed in an alkaline solution of more than pH 8 and then they were extracted into m-xylene. It was known that the each metallic ion formed 1 : 1 complex with the salphen and the logarithmic values of extraction constants for the complexes were 3.3 5.1 as an average value. Based on the preliminary study, the procedure was fixed for the separation and concentration of the analytes in samples. Various conditions such as the pH of solutions, the influence of $NaClO_4$, the bubbling rate and time of $N_2$ gas, and the type of organic solvent were optimized. The metal-salphen complexes could be extracted into m-xylene from the solution of more than pH 8, but the pH could be shifted to acidic solution of pH 6 by the addition of $NaClO_4$. In addition, the solvent sublation efficiency of the analytes was increased by adding $NaClO_4$. The recovery of 97-115% was obtained in the spiked samples in which given amounts of 0.3 mg/L Ni(II), 0.8 mg/L Co(II) and 0.04 mg/L Cu(II) were added.

• Journal of the Korean institute of surface engineering
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• v.47 no.4
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• pp.147-154
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• 2014

Formation behavior of PEO (Plasma Electrolytic Oxidation) films on AZ31 Mg alloy was studied in aqueous solutions containing various concentrations of hydroxide ion ($OH^-$) and silicate ion ($SiO_3{^{2-}}$) by voltage-time curves, and corrosion resistance of the PEO film-covered specimen was investigated by immersion test in 0.5 M NaCl solution. From the analyses of the voltage-time curves, it is suggested that two different types of anions are essentially needed for the formation of PEO films on AZ31 Mg alloy: film formation agent and local film breakdown agent. $SiO_3{^{2-}}$ ion acts only as a film formation agent but $OH^-$ ion acts not only as a film formation agent but also film breakdown agent. The PEO films prepared on AZ31 Mg alloy in alkaline silicate solution showed very good corrosion resistance without any pitting or filiform corrosions up to 480 h of immersion in 0.5 M NaCl.

• The Korean Journal of Ecology
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• v.25 no.2
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• pp.101-107
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• 2002

Three species of Chenopodiaceae, i.e. Suaeda japonica, Salicomia herbacea, Beta vulgaris var. cicla, were investigated to compare the physiological characteristics through inoic balances and osmoregulations under different environmental salt gradients. Plats were harvested in two weeks from treatments with salt gradients (0, 50, 100, 200 and 400 mM NaCl) and mineral nutrition gradients(1/1, 1/5, 1/10 dilutions of Hoagland solution). Plants were analyzed for growth responses, ionic balances, osmolalities, conductivities, glycinebetaine and proline contents quantitatively. Three plants of Chenopodiaceae accumulated slats into tissues unlike some salt sensitive species, and showed unique adaptation patterns to overcome saline environments, i.e. strong growth stimulation for Salicomia herbacea, growth negative tolerance for Suaeda japonica, and growth positive tolerance for Beta vulgaris var. cicla. The absorption of inorganic Ca/sup 2+/ ions was inhibited remarkably due to the excess uptake of Na+ with increasing salinity. The K+ content in plants was significantly reduced with increasing salinity. Total nitrogen content was reduced as mineral nutritions and salinity increased. Conductivity and osmolality increased with increasing salinity regardless of mineral nutritions. The ranges of glycinebetaine and proline contents were 0.2∼2.5 μM/g plant water and 0.1∼0.6μM/g plant water, respectively.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.29-33
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• 2014

The electrochemical characteristics of Al-Si casting alloys (Al-10%Si, Al-9%Si, Al-7%Si) in 3.5% NaCl solution at room temperature was studied using potentiodynamic techniques. The electrochemical values of corrosion potential($E_c$), corrosion current density($I_c$) and corrosion rate(mpy) were examined. The Al-Si alloys had several compounds such as $Mg_2Si$, ${\pi}$-$Al_8Si_6Mg_2Fe$ and $Al_2CuMg$ which could affect corrosion resistance significantly. The potentiodynamic polarization curve exhibited typical active behavior in anodic polarization curve. The major corrosion mechansim for the Al-Si alloys were pitting and grain boundary corrosion. As increasing Si and Cu contents, their corrosion resistance was decreased.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2616-2622
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• 2013

A novel zwitterionic monomer 3-[(2-acrylamido)dimethylammonio]propanesulfonate (DMADAS) was designed and synthesized in this study. Then it was polymerized with acrylamide (AM) by free radical polymerization in 0.5 mol/L NaCl solution with ammonium persulfate ($(NH_4)_2S_2O_8$) and sodium sulfate ($NaHSO_3$) as initiator. The structure and composition of DMADAS and acrylamide-3-[(2-acrylamido)-dimethylammonio]propanesulfonate copolymer (P-AM-DMADAS) were characterized by FT-IR spectroscopy, $^1H$ NMR and elemental analyses. Isoelectric point (IEP) of P-AM-DMADAS was tested by nanoparticle size and potential analyzer. Solution properties of copolymer were studied by reduced viscosity. Antipolyelectrolyte behavior was observed and was found to be enhanced with increasing DMADAS content in copolymer. The results showed that the viscosity of P-AM-DMADAS is 5.472 dl/g in pure water. Electrolyte was added, which weakened the mutual attraction between sulfonic acid group and quaternary ammonium group. The conformation became loose, which led to the increase of reduced viscosity. The ability of monovalent and divalent cation influencing the viscosity of zwitterionic copolymer obeyed the following sequence: $Li^+$ < $Na^+$ < $K^+$, $Mg^{2+}$ < $Ca^{2+}$ < $Ba^{2+}$, and that of anion is in the order: $Cl^-$ < $Br^-$ < $I^-$, $CO{_3}^{2-}$ > $SO{_3}^{2-}{\approx}SO{_4}^{2-}$.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.579-584
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• 1996

The molecular weight of the purified nucleoside oxidase estimated by gel filtration column chromatography was 480,000 and the enzyme protein was composed of four nonidentical subunits (81,000, 69,000, 32,000 and 16,000). On the basis of the visible absorption spectra and the enzymatic determination of the purified enzyme, the enzyme was supposed as a hemoprotein and also a flavoprotein containing 3 moles of FAD per I mole of enzyme. The isoelectric point of the enzyme was pH 5.1. Addition of metal salts such as 1 mM SnCl$_{2}$ and PbCl$_{2}$ into an enzyme reaction solution inhibited the enzyme activity by 94 and 90%, respectively. The enzyme activity was also lost significantly by hemoenzyme inhibitors such as NaCN and NaN$_{3}$ and flavoenzyme inhibitor, acriflavine and quinacrine. The maximal nucleoside oxidase activity was observed at pH 7.0 and 55$\circ$C. The nucleoside oxidase was relatively stable in the range of pH 5.5-9.0 and below 55$\circ$C.

• Journal of Welding and Joining
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• v.7 no.1
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• pp.51-58
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• 1989

The purpose of this study is to investigate the corrosion fatigue crack growth of PWTHT specimens(SS41, SM53B) which are the compact tension ones extracted from the muti-passed weldment and weld block. The corrosion fatigue test was done at the cyclic stress frequency of 3Hz in 3.5% NaCl solution. The results are as follows. 1. Corrosion fatigue crack growth of as-weld was slower than that of base metal. 2. In the low .DELTA.K region, the effect of corrosion environment on crack growth was obvious. However, the corrosion effect decreased with the .DELTA.K slowly. 3. The behaviour of fatigue and corrosion fatigue crack growth depended on the material, heat treatment as well as experimental conditions. 4. Corrosion fatigue crack growth of PWHT specimens(SS41, SM53B) subjected to 1/4hr, was increased compared with that of as-weld. 5. There was a tendency that the exponent value(m) obtained in 3.5% NaCl solution was decreased in comparison with that in air, and the material constant(C)was increased for Paris equation, da/dN=C((.DELTA.K))$^{m}$ , compared with that in air considerably.