• Korean Journal of Soil Science and Fertilizer
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• v.28 no.3
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• pp.218-226
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• 1995

Ion exchange equilibria in bulk and rhizosphere soil collected from peach seedlings were studied to find exchange equations that could be used in chromatographic models dealing with movement and distribution of fertilizer ammonium and exchangeable cations in soil profiles. Soil samples were equilibrated with mixtures of $NH_4Cl$, KCI, and $CaCl_2$ solutions and then extracted with $Sr(NO_3)_2$ solution to determine exchangeable cation compositions at equilibrium. Exchange data were fitted to Vanselow's, Gapon's, and Kerr's equations, but those formulations did not adequately describe the equilibria. An empirical equation of the form : ${\frac{\alpha_i^m}{a_j^n}}=K{\frac{(iX)^{mPi}}{(jX)^{nPj}}}$ which has an exponent on each of the exchangeable cation concentrations could describe the equilibria very well over the range of treatments. In this equation ${\alpha}^i$ and ${\alpha}^j$ are activities of cation i and j with valences m and n respectively. (iX) and (jX) are concentrations of exchangeable cations. Mole or equivalent fractions can be considered as the exchangeable ion concentration unit. Arbitrary constants $P_i$ and $P_j$, and distribution coefficient K can be found with multiple regression for the logarithmic form of the equation.

• Journal of Hospice and Palliative Care
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• v.7 no.1
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• pp.29-36
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• 2004

Purpose: A quantitative descriptive study aimed to identify the relationships between spiritual well-being and perception attitudes of death in nursing students. Methods: A survey was conducted and 175 data were collected. Collected data were computed and analyzed using SPSS10.0 for Win. 1) Descriptive statistics were used to identify demographic data, and 2) both t-test and ANOVA statistics were used to figure out the relationships between spiritual well-being /or perception attitudes of death and demographic data of the participants. 3) Pearson's correlation coefficient was used to identify the relationships between the two main variables. Results: 1) The mean of spiritual well-being score of the participants was $50.9943{\pm}10.7235$. Significant relationships between religion /or doing economic activity and spiritual well-being were found. 2) The mean of perception attitudes of death was $20.4914{\pm}2.6280$. There were significant relationships between gender /or age and perception attitudes of death among participants. 3) A strong positive relationship between spiritual well-being and perception attitudes of death of participants was also found(r=.261, P=.000). Conclusion: The study results shows that spiritual well-being of nursing students as caregivers of terminal patients is important when the perception of death of terminal patients is considered. Previous studies indicate that caregivers' perception attitudes impact on those of terminal patients. Therefore, it is suggested that not only perception attitudes of death and spiritual well-being in terminal patients, but also those of caregivers are importantly required to consider in educational programs in relation to spiritual care of terminal patients.

• Journal of Nutrition and Health
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• v.23 no.3
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• pp.170-178
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• 1990

The aim of the study was to investigate prevalence of obesity among housewives residing in apartments in Taegu city and any relationship of obesity with various factors. Hundred three housewives aged 30-49 years living in apartments (over 30 pyung) were interviewed for socio-economic status, food habit, food intake by a convenient questionnaire, and daily activity by the 24-hour recall. Their weight, height and triceps skinfold thickness were measured. The results were summarized as follows: 1) The percentages of subjects and their spouses with college and higher education were as much as 53.6% and 83.5%, respectively. The commonest family size was four members with two children. 2) The percentages of subjects classified as underweight, normal, overweight, and obesity according to relative body weight(RBW) were 4.9, 44.7, 24.3 and 26.2, respectively. Twenty four percent belonged to obese group according to body mass index(BMI$\geq$25). 3) Food habit score was 12.4 points in average and judged 'good'. The average of daily energy intake was 2247㎉ which corresponded to 112% of RDA and intakes of nutrients except iron exceeded RDA. The means of food habit score and energy intake were not significantly different among 4 groups. 4) Multiple regression analysis was tested to explain a relationship between fatness and various factors. The equation, BMI=25.216+(0.836$\times$family size)-(0.309$\times$education, years)-(0.00503$\times$household work time, minutes), indicates that fatness of housewives was related with family size(+), educational level(-) and household work time(-). These relationships were statistically significant(p<0.001) and R2 (coefficient of determination) was 0.237.

• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.78-84
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• 2019

Recently, bio-butanol is being promoted as environmentally friendly sustainable energy. However, some problems are still obstacle for commercialization of bio-butanol: the development of cheap biomass and enhancement of fermentation ratio and preparation of economical separation process for fermented products. In the conventional ABE biobutanol fermentation process, organic acids with acetone, butanol, and ethanol are produced. Therefore, it is necessary to study phase equilibrium data and mixture properties for the design and operation of separation process. However, there is lack of design data for organic acids except acetic acid contained system. In this study, therefore, binary solid-liquid equilibria (SLE) and mixture properties: the excess molar volumes ($V^E$), molar refraction deviation (${\Delta}R$) and deviation of viscosity (${\Delta}v$) at 298.15 for $C_3-C_6$ organic acid were reported. The experimental SLE data were correlated with the NRTL and UNIQUAC activity coefficient model with less than 0.5 K of root mean square deviation (RMSD). In addition, $V^E$, ${\Delta}R$ and ${\Delta}v$ for the same binary systems were satisfactorily fitted using the Redlich-Kister polynomial with less than ca. 0.004 standard deviation.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.96-102
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• 2019

When GGBFS(Ground Granulated Blast Furnace Slag) with high blaine is incorporated in concrete, compressive strength in the initial period is improved, but several engineering problems arise such as heat of hydration and quality control. In this paper, compressive strength and durability performance of concrete with 3,000 Grade-low fineness slag are evaluated. Three conditions of concrete mixtures are considered considering workability, and the related durability tests are performed. Although the strength of concrete with 3,000 Grade slag is slightly lower than the OPC(Ordinary Portland Cement) concrete at the age of 28 days, but insignificant difference is observed in long-term compressive strength due to latent hydration activity. The durability performances in concrete with low fineness slag show that the resistances to carbonation and freezing/thawing action are slightly higher than those of concrete with high fineness slag, since reduced unit water content is considered in 3,000 Grade slag mixture. For the long-term age, the chloride diffusion coefficient of the 3000-grade slag mixture is reduced to 20% compared to the OPC mixture, and the excellent chloride resistance are evaluated. Compared with concrete with OPC and high fineness GGBFS, concrete with lower fineness GGBFS can keep reasonable workability and durability performance with reduced water content.

• Korean Journal of Applied Biomechanics
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• v.29 no.3
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• pp.157-166
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• 2019

Objective: This study examined the effects of stimulating fingertip temperature on the patterns of force sharing and stability properties during multi-finger force production tasks. Method: 9 adult subjects (male: 3, female: 6, age: $26.11{\pm}4.01yrs$, height: $169.22{\pm}5.97cm$, weight: $61.44{\pm}11.27kg$) participated in this study. The experiment consisted of three blocks: 1) maximal voluntary contraction (MVC) task, 2) single-finger ramp task to quantify enslaving (i.e., unintended force production by non-task fingers), and 3) 12 trials of multi-finger steady-state force production task at 20% MVC. There were three temperature conditions including body-temperature (i.e., control condition), $40^{\circ}C$, and $43^{\circ}C$, and the stimulation was given to the index finger only for all experimental conditions. Results: There were no significant differences in the MVC forces, enslaving, and the accuracy of performance during the steady-state task between the conditions. However, the share of stimulated index finger force increased with the index fingertip temperature, while the share of middle finger force decreased. Also, the coefficient of variation of both index and middle finger forces over repetitive trials increased with the index fingertip temperature. Under the framework of the uncontrolled manifold (UCM) hypothesis used to quantify indices of multi-finger synergies (i.e., stability property) stabilizing total force during the steady-state task, the two variance components within the UCM analysis increased together with the fingertip temperature, while no changes in the synergy indices between the conditions. Conclusion: The current results showed that fingertip temperature stimulation only to index finger does not affect to muscle force production capability of multi-finger, independence of individual fingers, and force production accuracy by the involvement of all four fingers. The effect of fingertip temperature on the sharing pattern and force variation may be due to diffuse reflex effects of the induced afferent activity on alpha-motoneuronal pools. However, the unchanged stability properties may be the reflection of the active error compensation strategies by non-stimulated finger actions.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.301-308
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• 2019

The antioxidant properties of Eriobotrya japonica leaf extract were investigated using DPPH and ABTS radical scavenging assay. The 80% ethanol extract of leaves ($IC_{50}$ values for DPPH and ABTS were 13.9 and $10.9{\mu}g/mL$, respectively) and young leaves ($IC_{50}$ values for DPPH and ABTS were 20.7 and $17.3{\mu}g/mL$, respectively) showed high radical scavenging activity. Additionally, the quantitative method for estimation of ellagic acid and chlorogenic acid from E. japonica leaves was optimized by HPLC/DAD. This method showed high linearity of the calibration curve with a coefficient of correlation ($R^2$) equal to 0.999. The LOD values for ellagic acid and chlorogenic acid were 2.35 and $0.73{\mu}g/mL$, respectively, whereas LOQ values were 7.13 and $2.22{\mu}g/mL$, respectively. Recovery of the two compounds was 99.7-108.0% with RSD values less than 5.31%. These results suggest that 80% ethanol extract of E. japonica leaves could serve as a potential source of natural antioxidant for us in various industrial applications.

• Resources Recycling
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• v.28 no.3
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• pp.15-20
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• 2019

The recovery of struvite using nitrogen and phosphorus in wastewaters is useful for prevention of eutrophication and use as fertilizer, but there are theoretical and technical issues to be resolved. Through the detailed literature review, this study discusses the possible reasonable prediction of struvite formation reaction by setting a feasible reaction equation with some theoretical considerations. In a technical aspect, the purity of struvite in solid precipitates can be promoted by excluding Ca in an effective way. As for the struvite reaction prediction issue, selection of proper equilibrium reaction as well as its reaction equilibrium coefficient is significant in the neutral and basic pH regions. The equilibrium reaction agrees well with the experimental batch test results. Considering the charge balance of the ions, the pH drop along struvite formation in a diluted solution can be predicted. Also, improvement of struvite purity through elimination of Ca can be expected by providing a highly concentrated ${NH_4}^+-N$ relative to ${HPO_4}^{2-}-P$ because ${NH_4}^+$ can enhance the thermodynamic driving force toward favorable struvite formation. Even though the phosphate reacts rapidly with Ca to form a solid precipitate, the thermodynamic driving force due to the high ${NH_4}^+$ activity can dissociate the phosphate-calcium precipitates and produce struvite.

• Korean Journal of Medicinal Crop Science
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• v.27 no.2
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• pp.115-125
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• 2019

Background: Glycyrrhiza radix (licorice root) have been used as an oriental medicine material for long time, and its protective effects on oxidative stress, inflammation and cognition deficit have been recently reported. However, the cultivation of Glycyrrhiza species as medicinal crops is associated with some problems such as low productivity and early leaf fall, etc. To resolve this problems, Glycyrrhiza cultivars have been developed by direct hybridization of each Glycyrrhiza species by Korean researchers. The present study was conducted to compare the Glycyrrhiza cultivar radix (Dagam, Sinwongam and Wongam) for their anti-oxidation, anti-inflammation, and cognition improvement effects and levels of liquiritin, isoliquiritigenin and licochalcone in order to select an excellent cultivar as a material resource. Methods and Results: For evaluating the inhibitory efficacies of the Glycyrrhiza cultivar extracts on oxidative stress and inflammation in BV2 cells, we measured their reactive oxygen species (ROS) production and nitric oxide (NO) release after treating them with lipopolysccharide. The scavenging activities on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and peroxynitrite ($NOO^-$) radicals were evaluated. Cell proliferation and N-methyl-D-aspartate receptor (NMDAR) inhibition were analyzed. The total phenol, liquiritin, isoliquiritigenin and licochalcone A content in the extracts of the three culivars were quantified. Furthermore, the correlation coefficient between the activities and contents of total phenol, liquiritin, isoliquiritigenin and licochalcone A were also calculated. The results indicated that Sinwongam exhibited potent anti-oxidant, anti-inflammatory and NMDAR inhibititory activities. Sinwongam also showed higher total phenol and licochalcone A contents than the other cultivars. Among the three cultivars, Dagam exhibited a positive effects on NO release inhibition, cell proliferation and contents of liquiritin and isoliquiritigenin. Conclusions: Sinwongam is expected to be the most useful resource as a functional material for anti-oxidation/anti-inflammation and cognition improvement among the three studied licorice cultivars.

• The Journal of the Korea Contents Association
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• v.19 no.5
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• pp.389-403
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• 2019

This study has a purpose, that investigating influence of learning characteristic, lifelong learning participation motive, and wisdom that adult has at learning outcome and whether it has mediating effect of wisdom at influence that learning characteristic and lifelong learning participation motive have. For this, the subjects of the study was 425 adult learners from 20 to 69 years old who participated or are participating at Seoul, Incheon, and Gyeonggi-do. The results of this study are as in the following. At first, as a result of investigating relationship between learning characteristic, lifelong learning participation motive, wisdom, and learning outcome, the correlation coefficient of all variables appeared meaningfully. Second, as a result of investigating influence that learning characteristic, lifelong learning participation motive, and wisdom have in learning outcome, the most influential variable was learning value, the rest were cognitive capability, activity direction motive, learning direction motive and positive life attitude in this order. The third, as a result of investigating mediation effect of wisdom at influence that learning characteristic and lifelong learning participation motive have in learning outcome, Wisdom at the influence that learning characteristic have on learning outcome had completely mediated effect, and the wisdom at the influence that lifelong participation motive have on learning outcome had partially mediated effect. Thus, it was shown up that adult's learning characteristic and lifelong learning participation motive are able to increase effectively learning outcome by mediating wisdom. Therefore it is implying that it is essential to consider learning characteristic and lifelong learning participation motive in lifelong education field, and learning circumstance related with wisdom is important, as wisdom is important variable for increasing learning outcome.