• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.131-140
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• 1993

To study the corrosion fatigue begavior of T.M.C.P. steel, the rotary bending fatigue test with the change of concentration of NaCl solution was carried out. Fatigue life in the corrosion environment is decreased markedly in comparision with that in the air. Fatigue limit in the air was about 225 MPa. In case of 3.5% NaCl solution fatigue life could be expressed as .sigma./sub f/=10,392 * (N/sub f/)/sup -o.2923 . According to the paris's rule, crack growth rates could be expressed as da/dN=2.62.*10/sup -7/ .DELTA. K/sup 1.09/(3.5% NaCl solution), da/dN=1.95 *10/sup -7 .DELTA. K/sup 1.05/(1% NaCl solution), da/dN=2.62 * 10/sup -7/.DELTA./sup 0.72/(0.01% NaCl solution) with da/dN expressed in mm/cycle and .DELTA.K in MPa.GAMMA.m. The crack growth rate in the corrosion environment was highest under 3.5% NaCl solution.

• Food Science of Animal Resources
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• v.25 no.3
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• pp.340-343
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• 2005

The objective of this work was to study separation of short peptide (glycine-tyrosine) by using supported liquid membranes (SLMs) containing Aliquat as a cationic carrier, In the present investigation, the influence of pH of donor phase, concentrations of carrier and salt concentrations of acceptor phase on separation flux rate were investigated. Below pH 7.0 the flux rate was not affected by NaCl concentration or carrier concentration. However, the rate was increased significantly above pH 7.0. The rate with Hossain's SLM(H-SLM) containing $20\%$ Aliquat was about 3-fold higher with pH 9.0 at 0.25 M NaCl and 10-fold higher with pH 8.0 at 1.0 M NaCl than that with Duggan's SLM(D-SLM) containing $8\%$ Aliquat respectively. Furthermore, the rate with H-SLM was 10-fold higher at 1.0 M NaCl than the rate with 0.25 M NaCl, In conclusion, it would appear that the rate of separation was facilitated by using high salt concentrations together with high carrier concentrations above pH 7.0.

• Applied Biological Chemistry
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• v.25 no.2
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• pp.99-104
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• 1982

Natural zeolite rock was pulverized and dispersed in water. Clay fraction was collected by sedimentation method. The dominant clay mineral was Clinoptiolite with some Mordenite and Smectite. $P^{32}$ adsorption on Na-zeolite was determined in different ionic strengths using $P^{32}$ isotope by sludge method. The lower the pH of suspension, the longer the contact time, and the more the amount of zeolite, the more inorganic P was adsorbed by Na-zeolite, whereas the more P adsorption per unit gram of zeolite was observed at a 100mg addition than a 200mg in same volume of P-NaCl solution (20ml), indicating that the whole positively charged surface of Na-zeolite was not occupied by inorganic P. Furthermore, the more P adsorption on Na-zeolite was observed in higher ionic strength than in the lower. The maximum P adsorption on Na-zeolite was about 1me/g, and the zero point charge (ZPC) is assumed to be below pH 3.7.

• Journal of Environmental Science International
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• v.20 no.10
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• pp.1337-1345
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• 2011

The removal performances of divalent heavy metal ions ($Pb^{2+}$, $Cu^{2+}$, $Cd^{2+}$, $Sr^{2+}$ and $Mn^{2+}$) were studied using the Na-P1 zeolite synthesized from Jeju scoria in the batch and continuous fixed column reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite decreased in the order of $Pb^{2+}$ > $Cu2^{2+}$ > $Cd^{2+}$ > $Sr^{2+}$ > $Mn^{2+}$ based on the selectivity of each ion to ionic exchange site of Na-P1 zeolite for single and mixed solutions in batch or continuous fixed column reactor. For mixed solution, each heavy metal ion uptake was lower than that in single solution, and especially the uptake for $Mn^{2+}$ decreased greatly. In batch reactor, the uptakes of heavy metal ions by synthetic Na-P1 zeolite were described by Freundlich or Langmuir equation, but they followed the former better than the latter. In continuous fixed column reactor, the maximum ion exchange capacity obtained for each of heavy metal ions, was about 90----- of that in batch reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite increased with the increase of initial heavy metal concentration and solution pH, and the decrease of the amount and particle size of synthetic zeolite.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.587-592
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• 2016

Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). Properties of $NaBH_4$ hydrolysis reaction using unsupported Co-P-B Co-B, catalyst at high concentration $NaBH_4$ solution were studied. In order to enhance the hydrogen generation yield at high concentration of $NaBH_4$, the effect of catalyst type, $NaBH_4$ concentration and recovery of condensing water on the hydrogen yield were measured. The yield of hydrogen evolution increased as the boron ratio increased in preparation process of Co-P-B catalyst. The hydrogen yield decreased as the concentration increased from 20 wt% to 25 wt% in $NaBH_4$ solution during hydrolysis reaction using 1:5 Co-P-B catalyst. Maximum hydrogen yield of 96.4% obtained by recovery of condensing water and thinning of catalyst pack thickness in reactor using Co-P-B with Co-B catalyst and 25 wt% $NaBH_4$ solution.

• The Korean Journal of Physiology
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• v.22 no.2
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• pp.281-293
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• 1988

The effect of pH on the rate of PAH uptake was studied in rabbit renal basolateral membrane vesicles (BLMV) and brush border membrane vesicles (BBMV). In the absence of Na in incubation medium, a decrease in external $pH(pH_0)$ led to an increase in probenecid-sensitive PAH uptake by BLMV. In the presence of Na, the probenecid-sensitive PAH uptake was unaltered when the $pH_0$ decreased from 8.0 to 6.0 but further decrease in $pH_0$ to 5.5 increased significantly the uptake. The probenecid-sensitive PAH uptake was not affected by an alteration in pH per se in the absence of a pH gradient with or without the presence of Na. However, the presence of Na stimulated the probenecid-sensitive PAH uptake in all pH ranges tested over that measured in the absence of Na. A similar pattern of pH dependence on the PAH uptake was observed in BBMV but the presence of Na did not alter the probenecid-sensitive PAH uptake in the presence and absence of a pH gradient. Kinetic analysis for BLMV showed that Na or pH gradient increased Vmax of the probenecid-sensitive PAH uptake without a change in Km value. These results suggest that PAH is transported by $OH^-/PAH$ exchange process in the luminal membrane, but the pH dependence in the BLMV is not unequivocally consistent with an anion exchange process. The PAH transport is dependent on Na in BLMV but not in BBMV.

• Journal of Animal Science and Technology
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• v.63 no.2
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• pp.394-404
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• 2021

The objective of this study was to evaluate quality characteristics of low-nitrite emulsified-sausages (ESs, < 75 ppm) containing paprika oleoresin solution (POS) for replacing sodium nitrite (NaNO2). Pork ESs were prepared with four treatments (reference (REF), 150 ppm NaNO2; TRT1, 0 ppm NaNO2 + 0.1% POS; TRT2, 37.5 ppm NaNO2 + 0.1% POS; and TRT3, 75 ppm NaNO2 + 0.1% POS). The physicochemical and texture properties, microbial counts, residual nitrite and thiobarbituric acid reactant substances (TBARS) were measured during refrigerated storage of 35 days. Although TRT2 and TRT3 had lower levels of NaNO2, they had higher redness and yellowness than REF (p < 0.05). Microbial counts of total bacterial counts and Enterobacteriaceae of TRT2 and TRT3 were similar to those of REF (p > 0.05). Expressible moisture percentages (EM, %) of TRT2 and TRT3 were lower than those of REF (p < 0.05). TBARS values of TRT2 and TRT3 were not different from those of REF (p > 0.05). Among treatments, TRT1 had the highest TBARS values (p < 0.05). In conclusion, 0.1% POS in combination with 37.5 ppm NaNO2 would have quality characteristics similar to those of REF. Therefore, approximately 3/4 of the initial nitrite level could be replaced with 0.1% POS, and eventually developed healthier pork products.

• Journal of Electrochemical Science and Technology
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• v.11 no.2
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• pp.187-194
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• 2020

Two types of sodium cobalt pyrophosphates, triclinic Na_3.12Co_2.44(P₂O₇)₂ and orthorhombic Na₂CoP₂O₇, are compared as high-voltage cathode materials for Na-ion batteries. Na₂CoP₂O₇ shows no electrochemical activity, delivering negligible capacity. In contrast, Na_3.12Co_2.44(P₂O₇)₂ exhibits good electrochemical performance, such as high redox potential at ca. 4.3 V (vs. Na/Na⁺) and stable capacity retention over 50 cycles, although Na_3.12Co_2.44(P₂O₇)₂ delivered approximately 40 mA h g^-1. This is attributed to the fact that Na₂CoP₂O₇ (~3.1 Å) has smaller diffusion channel size than Na_3.12Co_2.44(P₂O₇)₂ (~4.2 Å). Moreover, the electrochemical performance of Na_3.12Co_2.44(P₂O₇)₂ is examined using Na cells and Li cells. The overpotential of Na cells is smaller than that of Li cells. This is due to the fact that Na_3.12Co_2.44(P₂O₇)₂ has a smaller charge transfer resistance and higher diffusivity for Na⁺ ions than Li⁺ ions. This implies that the large channel size of Na_3.12Co_2.44(P₂O₇)₂ is more appropriate for Na⁺ ions than Li⁺ ions. Therefore, Na_3.12Co_2.44(P₂O₇)₂ is considered a promising high-voltage cathode material for Na-ion batteries, if new electrolytes, which are stable above 4.5 V vs. Na/Na⁺, are introduced.

• Analytical Science and Technology
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• v.8 no.4
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• pp.793-798
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• 1995

A new chromoionophore sym-(decyl)(2-hydroxy-5-nitrobenzyloxy)-dibenzo-16-crown-5 (1) has been synthesized for $Na^+$ photometry in aqueous media. Apparent $pK_a$ values of 1 in the presence of 0.10 M LiCl, NaCl, and KCl were measured by spectrophotometry in 50% 1,4-dioxane-50% water (v/v) and compared with the $pK_a$ of 8.68 in the presence of 0.10 M TMACl. A significant $pK_a$ shift to a lower pH was only observed for $Na^+$ (${\Delta}pH=1.31$) due to selective binding of 1 with $Na^+$. Based upon this $pK_a$ shift, chromoionophore 1 was found to selectively respond to $Na^+$ with a detection limit of $10^{-3}M$ and no interference from $K^+$ up to 0.05 M for detection of 10.0 mM $Na^+$ in 50% 1,4-dioxane-50% water (v/v).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.5
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• pp.210-213
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• 2011

Glass-ceramics composed of $5Na_2O-36CaO-10TiO_2-xP_2O_5$ could be obtained with $P_2O_5$ content as following procedure: 1) leaching out $Ca_3(PO_4)_2$ crystals between $Ca_3(PO_4)_2$ and $NaTi_2(PO_4)_3$ selectively in 1 N HCl solution for 2 days, and 2) exchanging $Na^+$ ion to $Ag^+$ ion in Ag($NO_3$) solution for 1 day. Scanning electron microscope (SEM) and X-rat diffractometer (XRD) were measured to verify the proper synthesis of glass-ceramics. And anti-bacteria test was accomplished using Staphylococus aureus bacteria. In the results of anti-bacteria test, the bacteria were died perfectly after 3 hours.