• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.148-156
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• 2015

In this study the differences in the sample size and sample input changes as characteristics of bio-oil oak(Quercus variabilis), the oak 0.5~2.0 mm of the oak weighing 300~900g was processed into bio-oil via fast pyrolysis for 1.64 seconds. In this study, the physico-chemical properties of biooil using oak were investigated. Fast pyrolysis was adopted to increase the bio-oil yield from raw material. Although the differences in sample size and sample input changes in the yield of pyrolysis products were not significantly noticeable, increases in the yield of bio-oil accounted for approximately 60.3 to 62.1%, in the order of non-condensed gas, and biochar. When the primary bio-oil obtained by the condensation of the cooling tube and the seconary bio-oil obtained from the electric dust collector were measured separately, the yield of primary bio-oil was twice as higher than that of the secondary bio-oil. However, HHV (Higher Heating Value) of the secondary bio-oil was approximately twice as higher than that of the primary bio-oil by up to 5,602 kcal/kg. The water content of the primary bio-oil was more than 20% of the moisture content of the secondary bio-oil, which was 10% or less. In addition, the result of the elemental analysis regarding the secondary bio-oil, its primary carbon content was higher than that of the primary bio-oil, and since the oxygen content is low, the water content as well as elemental composition are believed to have an effect on the calorific value. The higher the storage temperature or the longer the storage period, the degree of the viscosity of the secondary bio-oil was higher than that of the primary bio-oil. This can be the attributed to the chemical bond between the polymeric bio-oil that forms during the storage period.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.554-564
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• 1996

Oxygen reduction in an alkaline fuel cell was studied by using perovskite of $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$(x=0.00, 0.01, 0.10, 0.20, 0.35, and 0.50) as an oxygen electrode catalyst. The changes in the catalytic properties as a function of Fe content were investigated by XRD, TG, and TPR. XRD patterns gave different lattice parameters of the catalysts. TG study revealed that Fe was so stabilized in the perovskite structure as to be hardly reduced even up to $900^{\circ}C$, and the amount of oxygen which was eliminated at high temperature increased with the fraction of Fe because Fe induced the increase of Co-O binding energy. From TPR study, ${\alpha}$-(low temperature peak) and ${\beta}$-(high temperature peak)states were observed. The bond strength of the ${\beta}$-species which was associated strongly with Co of the perovskite increased proportionally with the fraction of Fe. The ${\alpha}$-species, reversible oxygen, was the active species in the oxygen reduction. The ${\alpha}$-peak temperature which reflected the binding energy between Co and ${\alpha}$-state oxygen moved to lower temperature with the increase of lattice parameter of the catalytst due to the increase of Fe content. The decrease in the binding energy increased the activity in the oxygen reduction, but the decrease of ${\alpha}$-species with the increase of Fe content decreased the activity. The increase in the surface area with Fe content had little effect on the activity.

• Economic and Environmental Geology
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• v.54 no.2
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• pp.299-308
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• 2021

Fe(II) released from mining activities is precipitated as various Fe(III)-oxyhydroxides when exposed to an oxidizing environment including mine drainage. Ferrihydrite, one of the representative precipitated Fe(III) minerals, is easy to adsorb heavy metals and other pollutants due to the large specific surface area caused by very low crystallinity. Ferrihydrite is transformed to thermodynamically more stable goethite in the natural environment. Hence, information on the transformation of ferrihydrite to goethite and the related mobility of heavy metals in the acid mine drainage is important to predict the behaviors of those elements during ferrihydrite to goethite transition. The behaviors of heavy metals during the transformation of ferrihydrite to goethite were investigated for core samples collected from an AMD treatment system in the Heungjin-Taemaek coal mine by using X-ray diffraction (XRD), chemical analysis, and statistical analysis. XRD results showed that ferrihydrite gradually transformed to goethite from the top to the bottom of the core samples. Chemical analysis showed that the relative concentration of As was significantly high in the core samples compared with that in the drainage, indicating that As was likely to be adsorbed strongly on or coprecipitated with iron oxyhydroxide. Correlation analysis also indicated that As can be easily removed from mine drainage during iron mineral precipitation due to its high affinity to Fe. The concentration ratio of As, Cd, Co, Ni, and Zn to Fe generally decreased with depth in the core samples, suggesting that mineral transformation can increase those concentrations in the drainage. In contrast, the concentration ratio of Cr to Fe increased with depth, which can be explained by the chemical bond of iron oxide and chromate, and surface charge of ferrihydrite and goethite.

• (The)Study of the Eastern Classic
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• no.59
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• pp.93-120
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• 2015

The purpose of this study is to explore the source of appealing which Gusadang Kim Nakhaeng's writing for ancestral rites is equipped with. Gusadang was one of the Confucianists in Yeongnam during the 18th century and was praised for his scholarly virtue of jihaenghapil and silcheongunghaeng. Although Gusadang's writing for ancestral rites and his teacher Milam Lee Jaeui's letters were even specially named as 'gujemilchal', there has been almost no research on Gusadang's writing for ancestral rites yet. Therefore, this study selects three pieces of Gusadang's writing for ancestral rites which are especially rich in emotional expression for discussion. Chapter 2 titled as 'the Reconstruction of Memory in a Microscopic Perspective' presents the reason why Gusadang's writing for ancestral rites is recognized even as a piece of work equipped with appealing. Writing for ancestral rites begins from the point that there exists memory that can be shared by both the living and the dead. In reconstructing the anecdote with the dead on the stage of ritual writing in detail, the writer's memory plays an important role. Chapter 3 titled as 'the Rhetorical Reconstruction of Elevated Sensitivity' examines rhetorical devices needed for writing for ancestral rites. Proper rhetoric is needed to upgrade the dignity of the ritual writing and arouse sympathy from the readers. Although writing for ancestral rites is supposed to express sadness in terms of its formal characteristics, it should not end up being a mere outlet of emotion. Chapter 4 looks into 'the Descriptive Reconstruction of Lamenting Sentiment'. There should be a clear focus of description to make the gesture of the living towards the being not existing in the world any longer an appealing story. While maintaining a distinct way of description, Gusadang organizes the noble character of the dead, pitiable death, the precious bond in the past, and the longing of those left for the dead systematically. Writing for ancestral rites is a field to mourn over the death and reproduce the sadness of the living through writing. To make the text written in that way get to work as ritual writing properly, it should be appealing necessarily. This study has found the fact that such appealing that gives life to ritual writing is grounded on authenticity.

• Journal of the Korean Society of School Health
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• v.4 no.2
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• pp.119-135
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• 1991

The study was designed to gain necessary basic data order to grasp health knowledge, attitude, practice level of middle and high school students and to analyse th problem and to point out the method of improvement in the field of school health education. The survery was carried out through this reporter's interview for 2,400 students who attend to ten schools in Young Nam area during the period of a month from 25 the June to 25th July 1989. The result of this study can be summaried as follows. 1. The total number of answers on the question was 2,346. As for general characteristics the percent of female middle school students was 60.6% and the percent of male students was 77.7%, 45.9% of high school students was evening school students. 52.9% of middle school students and 42.3% of high school students were borne in rural area. 2. The percentage of unknown and misunderstanding for Epidemic Hepatitis infection was 46.3% of middle school students and 29.6% of high school students. 3. The percentage of unknown and misunderstanding for Epidemic Hemorrhage fever infection was 85.6% of middle school students and 66.9% of high school students. 4. The percentage of right knowledge for AIDS infection was 66.0% of middle school students and 90.4% of high school students. 5. The percentage of right knowledge for Typhoid infection was 47.8% of middle school students and 69.4% of high school students. 6. The percentage of unknown and misunderstanding for Tuberculosis infection was 71.6% of middle school students and 62.2% of high school students. 7. As for personal hygiene, the percentage of toothbrushing after every meal was high level : 44.2% of middle school students and 42.0% of high school students. 8. 60.9% of middle school students take a bath twice a week, 49.2% oh high school students take a bath a week. Times of bath of middle school students was higher than that of high school students. 9.The percentage of washing hand after using toilet was 42.1% of middle school students and 35.1% of high school students. 49.0% of middle school students and 55.1% of high school students wash hand sometimes after using toilet. 10. The percentage of change of underwear twice a week was 57.6% of middle school students and 49.8% of high school students. 11. The percentage of habit of unbalanced diet was 30.% of middle school students and 27.6% of high school students. 50.8% of middle school students and 51.7% of high school students have balanced diet. 12. Index of health practice of personal hygiene can be summarized as follows. A. A case of middle school students. 1) The percentage of health practice index in male and female was 49.6% and 48.1% respectively. Index of female students was higher than that of male students. 2) As for parent's occupation, public servants and company emplyee was upper level. Farming was low level. 3) As for income level, middle, level with 56.5% was highest in high income level and low level with 27.4% was highest in low income level. B. A case of high school students. 1) Middle level of health practice index was 46.0% of male students, upper and low level was 32.4% and 28.0% of female students respectively. 2) Middle level of health practice index was high in farming and company employee and upper level was high in commerce and service, low level with 60.0% was high in unemployed. 3) Upper practice index 35.7% appears in the rich and low practice index 38.3% appears in the poor. 13. Average points of Health practice about personal hygiene were as follows. (Full marks at 4). A. A case of middle school. Female (1.87 point) was higher than male (1.26 point). Night time (2.03 point) was higher than day time (1.66 point) and middle or small cities (2.17 point) are high than any other places. As for parent's occupation, students whose parents are company clerk get high marks (2.32) and ten students whose parent's job are service get next high marks (2.20). B. A case of high school. Female (1.53 point) was higher than male (1.22 point), as parents educational level were higher the point were higher, and as income level was higher, the points of health practice (1.78) were higher, and as for parents occupation, service get highest point (1.93) and commerce get next high point (1.86) public servant get low point (1.66). 14. The percentage of experience in smoking was 11.9% of middle school students and 60.9% of high school students. 15. The percentage of experience in inhalation of bond and administrating LSD was 4.3% of male middle school students, 8.4% of female middle school students, 6.9% of male high school students and 4.2% of female high school students. The knowledge level of communicable disease infection are very low in middle and high school students and practice level of personal hygiene are also very low. As a whole we can evaluate that middle and high school students are low level of health knowledge and practice. In conclusion, we must consider preparation for school health education program through establishing of health subjects in the carriculum, and securing of health education teachers and using materials and media program of health education. It is very important to establish macroscopic policy and strategy for public health education and to get people have right knowledge and practice for health.

• Economic and Environmental Geology
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• v.56 no.5
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• pp.603-618
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• 2023

This study focused on evaluating the suitability of the WRK (waste repository Korea) bentonite as a buffer material in the SNF (spent nuclear fuel) repository. The U (uranium) adsorption/desorption characteristics and the adsorption mechanisms of the WRK bentonite were presented through various analyses, adsorption/desorption experiments, and kinetic adsorption modeling at various pH conditions. Mineralogical and structural analyses supported that the major mineral of the WRK bentonite is the Ca-montmorillonite having the great possibility for the U adsorption. From results of the U adsorption/desorption experiments (intial U concentration: 1 mg/L) for the WRK bentonite, despite the low ratio of the WRK bentonite/U (2 g/L), high U adsorption efficiency (>74%) and low U desorption rate (<14%) were acquired at pH 5, 6, 10, and 11 in solution, supporting that the WRK bentonite can be used as the buffer material preventing the U migration in the SNF repository. Relatively low U adsorption efficiency (<45%) for the WRK bentonite was acquired at pH 3 and 7 because the U exists as various species in solution depending on pH and thus its U adsorption mechanisms are different due to the U speciation. Based on experimental results and previous studies, the main U adsorption mechanisms of the WRK bentonite were understood in viewpoint of the chemical adsorption. At the acid conditions (＜pH 3), the U is apt to adsorb as forms of UO₂²⁺, mainly due to the ionic bond with Si-O or Al-O(OH) present on the WRK bentonite rather than the ion exchange with Ca²⁺ among layers of the WRK bentonite, showing the relatively low U adsorption efficiency. At the alkaline conditions (>pH 7), the U could be adsorbed in the form of anionic U-hydroxy complexes (UO₂(OH)₃^-, UO₂(OH)₄^2-, (UO₂)₃(OH)₇^-, etc.), mainly by bonding with oxygen (O^-) from Si-O or Al-O(OH) on the WRK bentonite or by co-precipitation in the form of hydroxide, showing the high U adsorption. At pH 7, the relatively low U adsorption efficiency (42%) was acquired in this study and it was due to the existence of the U-carbonates in solution, having relatively high solubility than other U species. The U adsorption efficiency of the WRK bentonite can be increased by maintaining a neutral or highly alkaline condition because of the formation of U-hydroxyl complexes rather than the uranyl ion (UO₂²⁺) in solution,and by restraining the formation of U-carbonate complexes in solution.