• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.319-325
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• 2018

The aim of the present study was to determine the influence of different fertilizer combinations on the growth, yield, and fruit quality of 'Duke' blueberry cultivar and the water quality of growth medium. The experiment was carried out with three year old 'Duke' blueberry bushes which were cultivated in containers ($60{\times}80{\times}40cm$) filled with 130 L peat moss and 40 L pearlite (v/v). Sawdust was used as the mulch in growth containers. Three different fertilizer combinations (FC) i.e., FC-1 consisted with standard solution, FC-2 consisted with nitrogen reduced by 10% from FC-1, and FC-3 consisted with nitrogen reduced by 20% from FC-1 were tested while, the ground water used as the control. The effects of different fertilizer combinations on shoot diameter, shoot length, number of shoots, leaf length, SPAD value (the relative content of chlorophyll), berry weight, soluble solids content, titratable acidity, and yield per bush in 'Duke' blueberry were examined. Also, the effects of different fertilizer combinations on pH, EC, $NH_4$ and $NO_3$ in 'Duke' blueberry growth medium were monitored. The highest pH and lowest EC, $NH_4$ and $NO_3$ in growth medium was recorded with control treatment during the experiment period. The maximum shoot diameter (3.7 mm) and shoot length (35.7 cm) was recorded for the FC-1. Highest number of shoots (47%) were recorded from 'Duke' blueberry bushes supplemented with FC-1 compared to other treatments. The fertilizer combinations supplemented with nitrogen showed significant influence on leaf length and SPAD value compared to control 'Duke' blueberry bushes. However, the fruit quality attributes, i.e., berry weight, soluble solids content, and titratable acidity were not significant different among fertilizer treatments. The significantly highest yields per bush were recorded for FC-1, FC-2, and FC-3, as 2.2, 2.9, and 2.7 kg, respectively compared to control (0.2 kg). Although, the FC-1 was supplemented with highest nitrogen content it resulted low yield per bush while having high number of shoots and vigorous growth.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.312-318
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• 2018

We investigated the effect of postharvest treatments of calcium chloride, lysophosphatidyl ethanolamine (LPE) or 1-methylcyclopropene (1-MCP) on fruit quality during simulated marketing in Asian pear (Pyrus pyrifolia Nakai). 'Whangkeumbae' pear fruits were immersed in 0.25, 0.5 or 1.0% $CaCl_2$ solution with or without ultrasound (40kHz) at $25^{\circ}C$ for 3min followed by storage at $1^{\circ}C$ for 30 days simulated as abroad exportation. After simulated marketing at $25^{\circ}C$ and 80% relative humidity (RH) up for 10 days, quality parameters were evaluated. Results indicated that the ultrasound and $CaCl_2$ treatment had a synergic effect on keeping the green skin color which showed lower $a^*$ value. The combination treatment of ultrasound and 0.5% and 1.0% $CaCl_2$ significantly reduced internal browning disorders, although severe skin blemish disorder (20-23%) occurred in 1.0% $CaCl_2$ treatment. 'Wonhwang' pears were immersed in 1,000ppm LPE for 3 minutes or were fumigated in 1,000 ppb 1-MCP for 12 hours, respectively. The results of the fruit quality survey during the 21 days of distribution period are as follows. The 1-MCP treatment was maintained at a constant flesh firmness of 33N or higher during the distribution period. The LPE treated fruits had a lower physiological disorder index than the untreated group, but showed a relatively higher value than the 1-MCP treated group. In the case of 1-MCP treatment, the fruit respiration rate was significantly lower than of untreated control ($6.0mL{\cdot}kg^{-1}{\cdot}hr^{-1}$) during the simulaed marketing period. Consequently, it was expected that the postharvest treatments of 0.5% calcium chloride in pararell with ultrasound and 1-MCP fumigation can help to maintain Asian pear quality during distribution period.

• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.141-152
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• 2020

The rapid on-site measurement of hydroponic nutrients allows for the more efficient use of crop fertilizers. This paper reports on the development of an embedded on-site system consisting of multiple ion-selective electrodes (ISEs) for the real-time measurement of the concentrations of macronutrients in hydroponic solutions. The system included a combination of PVC ISEs for the detection of NO₃, K, and Ca ions, a cobalt-electrode for the detection of H₂PO₄, a double-junction reference electrode, a solution container, and a sampling system consisting of pumps and valves. An Arduino Due board was used to collect data and to control the volume of the sample. Prior to the measurement of each sample, a two-point normalization method was employed to adjust the sensitivity followed by an offset to minimize potential drift that might occur during continuous measurement. The predictive capabilities of the NO₃ and K ISEs based on PVC membranes were satisfactory, producing results that were in close agreement with the results of standard analyzers (R² = 0.99). Though the Ca ISE fabricated with Ca ionophore II underestimated the Ca concentration by an average of 55%, the strong linear relationship (R² > 0.84) makes it possible for the embedded system to be used in hydroponic NO₃, K, and Ca sensing. The cobalt-rod-based phosphate electrodes exhibited a relatively high error of 24.7±9.26% in the phosphate concentration range of 45 to 155 mg/L compared to standard methods due to inconsistent signal readings between replicates, illustrating the need for further research on the signal conditioning of cobalt electrodes to improve their predictive ability in hydroponic P sensing.

• Food Science and Preservation
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• v.15 no.3
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• pp.421-426
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• 2008

In older to prepare functional food materials from Acanthopanax koreanum, changes of major constituents by extracting with water and ethanol were investigated Extracting 300 g of below 0.5 cm size dried sample in 7.5 L of water or $30{\sim}95%$ ethanol for 9 hr at $100^{\circ}C$ were carried out pH during extraction was between 4.0 and 6.5. Color b-value of extracts was increased according to lower ethanol concentration and longer extraction time. Color a-value and b-value was increased more in stem than in root Extracts were increased rapidly within $2{\sim}3\;hr$. The extract in $30{\sim}70%$ ethanol was $0.84{\sim}1.34%(w/v)$ with root Main free sugar of extracts was sucrose in root. The eleutherosides were extracted rapidly within 3 hr, moreover were increased in water or $30{\sim}70%$ ethanol more than 95% ethanol concentration. Extraction of acanthoic acid from root was more affected on ethanol concentration than extracted time, moreover it was detected only trace by extracting with water. Furthermore, acanthoic acid was extracted rapidly within 2 hr in $50{\sim}70%$ ethanol, and was extracted 3 times higher with 70% ethanol than with 30% ethanol. The content of acanthoic acid in residue after extraction was affected largely by extraction solvents. The extraction efficiency in 70, 50 and 35% of ethanol concentration was about 95, 90 and 35% respectively. The eleutherosides were extracted to 95% with water or nature of water and ethanol. Therefore, the reflux extraction in $40{\sim}70%$ ethanol concentration for $3{\sim}5\;hr$ was adequate for extraction of functional materials from Acanthopanax koreanum.

• Korean Journal of Plant Resources
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• v.30 no.4
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• pp.364-371
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• 2017

Limonium tetragonum is a halophyte grown naturally in the coastal region in South Korea. This study was conducted to investigate the effects of salt concentrations on seed germination, seedling growth, and antioxidant capacity of L. tetragonum. Seeds were collected from naturally grown plants of L. tetragonum and those at full maturity were used in this experiment. All experiments were performed at 0%, 0.5%, 1.0%, or 2.0% of salt concentrations. Seed germination rate was highest as 86% at $20^{\circ}C$ and followed as higher in order of $25^{\circ}C$, $30^{\circ}C$ and $15^{\circ}C$. The germination rate was about 80% at 0% or 0.5% of salt concentration, but it was very low at the salt concentrations higher than 1%. Growth of L. tetragonum seedlings showed no difference in Hoagland solution containing NaCl in the range of 0% to 1.0% and seedlings survived at 2.0% of NaCl concentration. As the salt concentration increased, the content of $Na^+$ in the shoot increased, but that of $K^+$, $Ca^{{+}{+}}$, or $Mg^{{+}{+}}$ decreased. The antioxidant activity and the content of total polyphenol and total flavonoid in the shoot were similar at 0% and 0.5% of NaCl and were highest at 2.0% of NaCl concentration. In conclusion, performance of seed germination and plant growth of L. tetragonum was highest at 0% and 0.5% of NaCl concentration, and showed no difference in antioxidant activity, total polyphenol contents, and total flavonoid contents at the same salt concentrations.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.83-89
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• 2010

We investigated the growth of cucumber plants, the uptake and use of mineral nutrients, such as $NO_3$-N, $NH_4$-N, $K^+$, $Ca^{+}^{+}$, $Mg^{+}^{+}$ and $Na^+$, absorbed from media solution, and the synthesis and distribution of soluble sugars under nutrient-deficient condition. Difference in plant growth revealed after 20 days of treatment. Nitrate uptake in nutrient-deficient condition was significantly reduced compared with nutrient-normal treatment, and its distribution was primarily in petioles, stem, roots and less in leaves. In contrast, ammonium content was markedly predominated in fast growing organs, and it was significantly different in growing leaves, expanded leaves, and roots under similar growth conditions. $K^+$, lack by deficient nutrient condition, was found in growing leaves. The $Ca^{+}^{+}$ content did not show significant difference between treatments and a substantial portion of $Ca^{+}^{+}$ remained in petioles. The $Mg^{+}^{+}$ content was significantly higher in the leaves of nutrient-normal condition compared with nutrient-deficient condition while significantly lower in stem and roots. The behavior of $Na^+$ in plant was similar to $K^+$ although its content was relatively little. The highest $CO_2$ assimilation was observed in fully expanded leaves of nutrient-normal condition, which was 1.7 times higher compared with nutrient-deficient condition. The instantaneous water use efficiency (A/E) and the A/gsratio, which is an index of leaf intrinsic water use efficiency for individual leaves, was 1.2 and 1.1 times higher, respectively. The total soluble sugar (TSS) contents were highest in leaves followed by petioles, stems and roots, and in younger leaves. The growing leaves contained about 7,200 mg $kg^{-1}$ of TSS in nutrient-normal condition whereas the TSS contents in nutrient-deficient condition were not significantly different between leaves. The $Mg^{+}^{+}$ and $NH_4$- N were positively correlated with the TSS whereas $NO_3$ - N was negatively correlated.

• Korean Journal of Crystallography
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• v.6 no.2
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• pp.125-133
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• 1995

The crystal structure of dehydrated, partially Co(II)-exchanged zeolite X, stoichiometry Co2+Na+-X (Co41+Na10Si100Al92O384) per unit cell, has been determined from three-dimensional X-ray diffraction data gathered by counter methods. The structure was solved and refined in the cubic space group Fd3:α=24.544(1)Å at 21(1)℃. The crystal was prepared by ion exchange in a flowing stream using a solution 0.025 M each in Co(NO3)2 and Co(O2CCH3)2. The crystal was then dehydrated at 380℃ and 2×10-6 Torr for two days. The structure was refined to the final error indices, R1=0.059 and R2=0.046 with 211 reflections for which I > 3σ(I). Co2+ ions and Na+ ions are located at the four different crystallographic sites. Co2+ ions are located at two different sites of high occupancies. Sixteen Co2+ ions are located at the center of the double six-ring (site I; Co-O = 2.21(1)Å, O-Co-O = 90.0(4)°) and twenty-five Co2+ ions are located at site II in the supercage. Twenty-five Co2+ ions are recessed 0.09Å into the supercage from its three oxygen plane (Co-O = 2.05(1)Å, O-Co-O = 119.8(7)°). Na+ ions are located at two different sites of occupandies. Seven Na+ ions are located at site II in the supercage (Na-O = 2.29(1)Å, O-Na-O = 102(1)°). Three Na+ ions are statistically distribyted over site III, a 48-fold equipoint in the supercages on twofold axes (Na-O = 2.59(10)Å, O-Na-O = 69.0(3)°). Seven Na+ ions are recessed 1.02Å into the supercage from the three oxygen plane. It appears that Co2+ ions prefer sites I and II in order, and that Na+ ions occupy the remaining sites, II and III.

• Korean Journal of Social Welfare
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• v.53
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• pp.129-153
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• 2003

This study examines the socio-economic impacts of recent welfare reform in the United States. Based on the neo-conservative critique to the traditional public assistance system for low-income families, the 1996 welfare reform has given greater emphases on reducing welfare dependency and increasing work effort and self-sufficiency among welfare recipients. In particular, the welfare reform legislation instituted 60-month lifetime limits on cash assistance, expanded mandatory work requirements, and placed financial penalties for noncompliance. With the well-timed economic boom in the second half of the 1990s, the welfare reform seems to achieve considerable progress; welfare caseload has declined sharply to reach less than 50% of its 1994 peak, single mothers' labor force participation has increased substantially, and child poverty has decreased. In spite of these good signals, the welfare reform also has several potential problems. Many welfare leavers participate in the labor market, but not all (or most) of them. The economic well being of working welfare leavers did not increased significantly, because earnings increase was canceled out by parallel decrease in welfare benefits. Furthermore, most of working welfare leavers are employed in jobs with poor employment stability and low wages, making them highly vulnerable to frequent layoff, long-time joblessness, persistent poverty, and welfare recidivism. Another serious problem of the welfare reform is that a substantial number of welfare recipients are faced with extreme difficulties in finding jobs, because they have severe barriers to employment. The new welfare system with 5-year time limit can severely threaten the livelihoods of these people. The welfare reform presupposes that welfare recipients can achieve self-reliance by increasing their labor market activities. However, empirical evidences suggest that many people are unable to respond to the new, work-oriented welfare strategy. It may be a very difficult task to achieve both objectives of the welfare reform((1) providing adequate income security for low-income families and (2) promoting self-sufficiency) at the same time, because sometimes they are conflicting each other. With this in mind, a possible solution can be to distinguish welfare recipients into "(Very)-Hard-to-Employ" group and "(Relatively)-Ready-to-Work" group, based on elaborate examinations of a wide range of personal conditions. For the former group, the primary objective of welfare policies should be the first one(providing income security). For the "Ready-to-Work" group, follow-up services to promote job retention and advancement, as well as skill-training and job-search services, are very important. The U. S. experiences of the welfare reform provide some useful implications for newly developing Korean public assistance policies for the able-bodied low-income population.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.182-190
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• 2009

Statement of problem: Microleakage at the occlusal and gingival margin of Class V cavities restored with composite resin has traditionally been considered an obstacle to successful restoration. Purpose: The aim of this study was to assess the effectiveness of three different surface sealants(Fortify, Permaseal and Biscover LV) on the marginal sealing of Class V light-activated composite resin restorations(Z250). Material and methods: Forty noncarious human premolars and molars extracted within a three-month period were selected. Class V cavities with the occlusal margin in enamel and gingival margin in cementum were prepared in both buccal and lingual surfaces. The teeth, randomly assigned in four groups with twenty cavities in each group, were restored with composite resin after applying an adhesive system(Clearfil SE bond). After the finishing and polishing procedures, the restorations were covered with a specific surface sealants, except for the control samples, which were not sealed. After placing restorations, the specimens were thermocycled, and immersed in a 2% methylene blue solution for twenty four hours and sectioned longitudinally. The marginal microleakage was evaluated at the occlusal and gingival interfaces using a microscope and compared among the four groups using ANOVA test and Wilcoxon Rank-Sum test($\alpha$=0.05). Results: Statistical analysis showed that there was significantly less leakage when the surface sealants were used than there was in control group(P<.05). There were no significant differences of microleakage at occlusal and gingival margins among groups. There were no significant differences between microleakage of occlusal and gingival margins in each group. Fortify was not statistically different from control group at the gingival margin(P>.05). Conclusion: Application of surface sealants was an effective method of surface coating in reducing microleakage at occlusal and gingival margins of Class V composite resin restorations. However, it is certain that some microleakage still occurred despite the application of surface sealants, especially gingival margins.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.161-174
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• 2011

The purpose of this study was to evaluate the effect of ethanol addition on efficacy of two-step total-etch adhesive under over-wet condition by measurement of remaining volatile part (RVP), microtensile bond strength (${\mu}TBS$), and degree of conversion (DC). Two-step total-etch adhesive, Optibond Solo Plus (Kerr, Orange, USA), was used. Experimental groups were divided into 8 groups: Group 1 (only 10 ${\mu}l$ adhesive), Group 2 (mixture of 3 ${\mu}l$ distilled water and 10 ${\mu}l$ adhesive), From Group 3 to Group 8 (mixture of 3 ${\mu}l$ distilled water, 10 ${\mu}l$ adhesive, and ethanol added in 1 ${\mu}l$ increment from 1 ${\mu}l$ to 6 ${\mu}l$). The mixtures were placed on slide glass and evaporated for 10 s, 30 s, and 60 s by air-drying. The weight of RVP was measured by precision weight. Same procedures were performed for ${\mu}TBS$ test and measurement of DC. The condition of mixed solution was observed under light microscope. For RVP weight, the weights of experimental groups except for group 1 decreased with the increase of air-drying time (p<0.05). The DC increased with the increase of air-drying time in only group 5 and 6 (p<0.05). The ${\mu}TBS$ increased with the increase of air-drying time in group only 5, 6, and 7 (p<0.05). The phase separation was examined and water blisters were diminished with the increase of air-drying time in group 5, 6, 7, and 8. Within the limits of this study, ethanol additionally applied to adhesive decreased RVP and increased DC and ${\mu}TBS$ under over-wet condition. It was shown that the addition of ethanol to two-step total-etch adhesive under over-wet condition would remove water and increase the efficacy of adhesive.