• Applied Chemistry for Engineering
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• v.21 no.3
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• pp.301-305
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• 2010

In this study, the alkaline degreasing agent was developed for electroplating pretreatment process, and the efficiency and the durability was predicted. The alkaline deeping degreasing agent was prepared by blending sodium hydroxide (NaOH), sodium carbonate ($Na_2CO_3$), sodium silicate ($Na_2SiO_3$), and sodium lauric sulfate (SLS). The performance tests of the degreasing agent were evaluated in the $40{\sim}50^{\circ}C$ of the degreasing temperature and 30~40 min of the degreasing time. The efficiency and durability of the prepared degreasing agent were tested by the waterdrop formation test and Hull-cell plating test. The optimum ratio of alkaline degreasing agent was NaOH (30 g/L) + SLS (6.0 g/L) + $Na_2SiO_3$ (2.0 g/L) + $Na_2CO_3$ (40 g/L). Also, the optimum degreasing conditions were $50^{\circ}C$ of the degreasing temperature and 35 min of the degreasing time.

• Resources Recycling
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• v.26 no.4
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• pp.88-94
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• 2017

The recovery of gold in cyclone type electrolytic cell was conducted from solution for stripping gold of PCB by cyanide. The electrolytic recovery behaviors of gold was investigated by reaction time and addition of electrolytic sodium hypochlorite (NaOCl) and gold plating additive (KG-120). Because the electrolysis generated NaOCl reacted with the cyanide in the leachate by alkaline chlorination, more than 99% of the cyanide was removed at a $NaOCl(g)/CN^-(g)$ ratio of 1.0. When NaOCl was added during the recovery of the gold from cyanide leachate in the cyclone electrolytic cell, the recovery of gold was 98% at the ratio of $NaOCl(g)/CN^-(g)$ from 0.5 to 2.5 in 480 minutes and decreased rapidly over the ratio of 3.0. Gold was recovered more than 99% by adding 1.5 and 4.5%(v/v) of KG-120 with NaOCl in 480 minutes. In particular, when the concentration of KG-120 was 3.5 and 4.5%(v/v), more than 96% of gold was recovered within 240 minutes and the initial recovery rate was relatively faster. The optimum concentration of KG-120 is 3.5%(v/v) considering the economic feasibility and efficiency.

• Horticultural Science & Technology
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• v.19 no.3
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• pp.342-347
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• 2001

The experiment was carried out to examine the effect of culture media and seawater on growth and mineral concentrations in Glasswort (Salicornia herbacea). Glassworts were grown in a greenhouse with 0, 10, 30 and 90% seawater and with or without nutrient media. The salinity tolerance affected on shoot height and Na, K and Ca concentrations significantly. The shoot height was increased with 10 and 30% seawater concentrations. At the higher seawater concentrations, more Na accumulated in a shoot was obserbed. The application of seawater concentration was effective on increasing Na, Mg, and Fe, concentrations and green leaf area rate and on decreasing K concentration. K/Na ratio of shoot was decreased at high seawater concentration, whereas Na concentrations was lowered at a low seawater concentrations. The mineral concentrations were changed according to the growing season. Na, K and Mg were high in June and Ca and P in September, respectively.

• Analytical Science and Technology
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• v.11 no.4
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• pp.248-253
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• 1998

The adsorption and separation behaviors of alkali, alkaline earth and transition metal ions using a poly-dibenzo-18-crown-6 were investigated in aqueous solution. The adsorption degree(E) and distribution ratio(D) of alkali, alkaline earth metal ions were Li(I)$t_R$) of metal ions were affected by the adsorption degree(E) and distribution ratio(D). This results showed good separation efficiency of K(I), Sr(II), Ag(I) and Pb(II) from the mixed metal solution.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.1
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• pp.19-27
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• 1996

The purpose of this study is the investigation of the physical properties, handle variation of polyester fabrics grafted methacrylic acid. The results are as follow 1. In the case of moisture recovery, MA-g-PET results in an improvement of approximately 4% when the graft ratio reaches 25%, whilst Na-MA-g-PET results in an improvement of approximately 9% when the graft ratio reaches 20%. 2. The static electricity of Na-MA-g-PET, is rarely generated when the graft ratio exceeds 10% . 3. The T.H.V. indicate that the values had deteriorated in the case of MA-g-PET, whilst the N a-Ma-a.PET values demonstrated superiority. 4. The value resulting from the MA-g-PET and Na-MA-g-PET treatment methods are calculated as being 0.0130, whilst the value pursuant to graft ratio is 0.0000.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.25-30
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• 2007

In this paper, lead-free [$Li_{0.04}(Na_{y}K_{1-y})_{0.96}](Nb_{0.86}Ta_{0.1}Sb_{0.04})O_{3}$ (y=0.4 - 0.58) ceramics were manufactured using conventional miked oxide method for acoustic emission(AE) sensor application and their dielectric and piezoelectric properties were investigated with the variations of Na/K ratio. The samples in the composition Na/K=54/46 exhibited excellent electrical properties of $d_{33}=300$ PC/N and kp=0.49. Taking into consideration above piezoelectric properties, it can be concluded that the [$Li_{0.04}(Na_{y}K_{1-y})_{0.96}](Nb_{0.86}Ta_{0.1}Sb_{0.04})O_{3}$ system ceramics are the promising lead-free materials capable of substituting PZT system ceramics.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.378-389
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• 2006

The purpose of this study was to compare the sealing ability of root canal obturation with or without the treatment of smear layer. Eighty extracted human teeth with one canal were selected Instrumentation was performed with crown-down technique. After instrumentation, root canals of the NaOCl group and NaOCl-6 group were irrigated with 3% NaOCl. EDTA group and EDTA-6 group were irrigated with 17% EDTA. Then all teeth were obturated using continuous wane obturation technique NaOCl group and EDTA group were immersed in methylene blue solution for 84hours. NaOCl-6 group and EDTA-6 group were immersed in methylene blue solution for 6months. The teeth were sectioned at 1.5 mn (Level 1), 3.0 mm (Level 2) and 4.5 mm (Level 3) from the root apex. The length of dye-penetrated inter-face and the circumferential length of canal at each level were measured using Sigma-Scan Pro 5.0. 1. The mean leakage ratio was decreased cervically. 2. NaOCl group showed higher mean leakage ratio than EDTA group at each level. But there was significant difference at level 1 only (p < 0.05). 3. NaOCl-6 group showed higher mean leakage ratio than EDTA-6 group at each level. But there was significant difference at level 1 only (p < 0.05). 4. NaOCl-6 group showed higher mean leakage ratio than NaOCl group at each level. But there was significant difference at level 1 only (p < 0.05). 5. EDTA-6 group showed higher mean leakage ratio than EDTA group at each level. But there was no significant difference. 6. In NaOCl group and NaOCl-6 group, scanning electron micrographs of tooth sections generally covered with smear layer. In EDTA group and EDTA-6 group, tooth sections showing the penetration of sealers to opened dentinal tubules. The results suggest that removal of smear layer was effective to reduce the apical microleakage of the root canal.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.1-8
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• 1992

This study was conducted to obtain the basic information on salt-tolerance of rice cultivars in relations with growth retardation and cation content. As the salt-level increased, less retardation in plant height and dry weight were shown in salt-tolerant than salt-susceptible rice cultivars. Salt tolerant cultivars showed lower N $a^{+}$ and higher $K^{+}$ content and lower N $a^{+}$ / $K^{+}$ ratio at each salt-levels than salt-susceptible ones, while there were no significant differences in $Ca^{++}$ and $Mg^{++}$ content. At the tillering stage, the plant height and dry weight of the salt-treated plots were significantly correlated with N $a^{+}$ and $K^{+}$ content and N $a^{+}$ / $K^{+}$ ratio, implying that N $a^{+}$ and $K^{+}$ content could be an indicator of salt-tolerance of a rice cultivar. There were no tiller-depending differences in cation content in all cultivars. N $a^{+}$ content and N $a^{+}$ / $K^{+}$ ratio in leaves were lower at the top and higher at the bottom. In three $F_1$ hybrids between salt tolerant parent Pokkali and three salt susceptible parents, plant height, dry weight, $K^{+}$ content and N $a^{+}$ / $K^{+}$ ratio were similar to those of Pokkali parent, while N $a^{+}$ content was intermediate of the parents. So, it seemed that salt tolerance is dominant over salt susceptibility. In $F_2$ of Pokkali/wx817 cross, genetic segregation of plant height, dry weight, $K^{+}$ content and N $a^{+}$ / $K^{+}$ ratio varied continuously and was biased onto Pokkali side, while that of N $a^{+}$ content showed normal distribution with intermediate mode. Broad-sense heritability of the characters ranged from 0. 604 to 0. 811. Genotypic and phenotypic correlation coefficients among them were relatively high.fficients among them were relatively high.h.h.

• Korean Chemical Engineering Research
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• v.55 no.3
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• pp.401-408
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• 2017

In preparation of self-repairing polymer-modified waterproofing asphalt-montmorillonite (MMT) composite, silylation-modification characteristics of cation ($Na^+$) exchanged K-10 (Na-MMT-K) using 3-aminopropyltriethoxysilane (APS) were studied and the optimal conditions of its silylation-modification process were proposed by use of the results of XRD analysis on silylation-modified Na-MMT-K (S-Na-MMT-K) under various conditions. According to XRD results, it was confirmed that peaks of Na-MMT-K were simultaneously consistent with those of K-10 and natural or Ca-MMT modified Na-MMT. Similarly, S-Na-MMT-K was observed to have two basal spacings ($d_{001}$), among which the area-ratio of a secondary (001) peak ($2{\theta}=3.9{\sim}4.2^{\circ}$) to a primary (001) peak ($2{\theta}{\sim}8.838^{\circ}$) was suggested to be a criterion to represent a degree of APS silylation-modification. Then, the optimal conditions on APS-stirring period prior to APS-MMT reaction, APS-MMT reaction period, APS concentration and reaction temperature at the highest area-ratio were turned out to be 20 min, 2~3 hr, 7.5 w/v% and $50^{\circ}C$, respectively.

• Korean Journal of Community Nutrition
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• v.4 no.3
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• pp.375-381
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• 1999

The purpose of this study was to investigate Na and K balances in healthy adult women. Anthropometric assessments, biochemical analysis of blood, 3-day dietary flood records and collections of 3-day food, 24-hr urine and faces were performed to evaluate intakes and excretions of Na and K in 20 college women living in Seoul. The mean BMI and blood pressure of the subjects were 21.08 and 110.25/67.50mmHg, respectively. Mean daily intake of energy was 1578.84kcal, 79% of Korean RDA. Also, daily intakes of Na and K ware 120.86mEq and 44.20mEq. The urinary and fecal excretions of Na were 99.88 and 4.45mEq/day, and those of K were 30.41 and 8.66mEq/day, respectively. The body retention, retention rate, and apparent absorption of Na were 17.11mEq, 13.23%, and 96.31%, and those of K were 5.82mEq, 8.69%, and 80.12%, respectively. The urinary and fecal Na/K ratio were 3.48 and 0.52. There were significantly positive correlations between 1) urinary Na, K excretions and intakes of Na or K, 2) urinary K and BMI, 3) serum K and serum globulin, and 4) urinary Na excretion and serum haptoglobin level, respectively. The results of this study show that Na intake was higher and K intake was lower than those of other advanced nations. Therefore, nutrition education show instruct people to reduce Na intake and to increase K intake.