• Journal of the Korean Society of Earth Science Education
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• v.10 no.3
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• pp.308-322
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• 2017

It is the purpose of the study to investigate how high school students understand the concept of carbon cycle according to their spatial perception ability. For this, a total of 30 male students and 33 female students, who belong to the science course of the 2nd grade at a general co-education high school located in a megalopolis of Korea and have finished the class of Earth Science I in the first semester, took part in the spatial perception ability test, and four male students and four female students were selected as members of two groups : one group of higher spatial perception ability and the other group of lower spatial perception ability, and they agreed to participate in the study and have got the test of the carbon cycle concept. The results are as followings. It was found that the students who had higher spatial perception ability recorded more scores in the carbon cycle concept, state change concept, and process concept at the factor of word association and the carbon cycle concept, state change and process concept at the factor of drawing than those who had lower spatial perception ability. Connecting link used in the systemic viewpoint was disclosed like this in the factor of causal map of those who had higher spatial perception ability : one student 2 and another one student 1 and the other two students 0 : and in the factor of drawing three students 1 and the other 0 ; But nothing was found in the factors of causal map and drawing of those who had lower spatial perception ability. In addition, it was also found that those students who had higher spatial perception ability, when compared with those students who had lower spatial perception ability, have understood the fact that carbon moves through the interaction of the earth system's lower parts; Three students, who showed higher spatial perception ability, had a low level of systemic thinking concept, and one student who had higher spatial perception ability and four students who had lower spatial perception ability did not have a systemic thinking concept.

• Journal of Food Hygiene and Safety
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• v.31 no.2
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• pp.74-84
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• 2016

Literacy on food additives of elementary school teachers (ET) and nutrition teachers (NT) could be influential factor on safe dietary education for school children. Therefore, the perceptions and information needs on food additives were surveyed from 351 elementary school teachers and nutrition teachers in metropolitan area of Korea, and the basic data for the promotion of risk communication on food additives among them were obtained. Compared to ET who consider 'taste' (39.1%) as the most important factor while purchasing food, NT considered 'safety' (68.1%) first (p < 0.001). Among the food labelling items, the level of understanding on food additives was the lowest both in ET (3.53) and NT (4.17), and NT showed better levels of understanding overall on food labels. Both ET and NT regarded hazardous factors of food as environmental pollutants, foodborne pathogens, and food additives in order, and tended to select 'no additives' or 'no artificial color' products while purchasing processed food. Although NT answered that they know all food additives had been passed the evaluation of safety and effectiveness tests (100%) and have standards of use (81.9%), majority of them (87.5%) believed the consumption of food additives are harmful on human health. ET (75.2%) also regarded food additives as dangerous materials. Above results suggested the necessity of proper and enough risk communication for both ET and NT. Both ET and NT wanted to have information on the safety or hazard of food additives. Most preferred media to get the information on food additives was TV (3.80) among ET and lecture (3.65) among NT. ET and NT trusted hospital, research institution/universities or the personnels working in these institutions as the provider of information on food additives. The result that the trust levels of ET and NT on government were relative low suggested the weakness of risk communication in Korean government. Although ET and NT answered that they do not trust mass media, their behaviors were affected by them such as reading food labels in ET (39.4%) and reducing the consumption of food additives in NT (50%). They also indicated mass media's problem of sensitive approach on food additives and asked the urgent reaction of government by providing sound information through experts on food additives. Above results revealed that ET and NT have different perceptions and information needs on food additives, therefore, proper risk communication should be provided for them to serve as dietary educators for elementary school children.

• 대한공업교육학회지
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• v.39 no.2
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• pp.19-36
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• 2014

The purposes of this study are to grasp industry vocational subject student-teachers' instruction area, compare cognitive level of cooperating teacher and student-teachers for the importance of instruction area and secure base data required to develop educational practical area of professional teachers in specialized high school. To achieve this, instruction area of instruction teacher in charge of industry vocational subject pre-teacher education was developed by document consideration and expert verification and differences of importance cognition for the area was compared between educational practice insturction teacher and student-teacher. The results are as the following. First, for the instruction areas that educational practice instruction teachers should teach student-teacher, there are 7 categories, 17 mid-fields and 85 subsections. Especially expert group suggested an opinion that areas of teacher's values and personality formation should be added to pre-teachers. And, they judged that category of school business showed low validity for educational practice instruction teacher's instruction area. Second, educational practice instruction teacher importantly cognized 'class activity', 'student instruction and class management' and 'development of desirable view of education attitude'. On the other hand, they cognized 'development and management of curriculum', 'support on educational activity', 'industrial-educational cooperation and tie with local community' and 'specialty improvement' less importantly. Student-teachers cognized 'class activity', 'student instruction and class management', 'specialty improvement', 'development of desirable view of education attitude' importantly. They cognized 'development and management of curriculum', 'support on educational activity' and 'industrial-educational cooperation and tie with local community' relatively less importantly. Third, both educational practice instruction teachers and student-teachers importantly cognized 'class activity', 'student instruction and class management' and 'development of desirable view of education attitude'. However, student-teachers importantly cognized, but educational practice instruction teachers didn't importantly cognized 'specialty improvement'. Both two group cognized 'development and management of curriculum', 'support on educational activity' and 'industrial-educational cooperation and tie with local community' less importantly.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.1-7
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• 2010

Purpose: To plan and improve consumers' satisfaction by analyzing consumers' purchasing behavior of spectacles. Also this will show the need of improvement in reliance of an optician. Methods: A total of 307 people (10 to 60 years) participated in individual questionnaires. Questionnaires comprised of general characteristic of surveyed people, purchasing spectacles behavior, satisfaction after purchasing spectacles, reliability of optician, and improvement points of optician. Results: Most important points in selecting the product were the design and the price of the spectacles. 142 people (46.3%) replied "average" and 140 people (45.6%) replied "satisfying" out of maximum point of satisfaction level which was 5 points. 72.3% of people have regularly visiting optical shop due to the high accessibility, after-sales care, and courteous optician. On the contrary, 27.7% replied "never visit same optician shop again" because of the low accessibility, minimal range of products, and high price. Data showed that people had high re liability about the opticians' knowledge of product, and their technique of eye refraction. Data revealed that people did not show high satisfaction about opticians' knowledge of ophthalmology, and price of products. Most important improvement points were accurate spectacle prescription by Opticians rating 42% of reply. Factors most considered during spectacle selection among the 10 to 20 age group were design by 34.8% and price by 10.1%. Among the 40 to 50 age group, most considered factors were design by 14% and spectacle frame material by 10.1%. Conclusions: Satisfaction rate of purchasing spectacles for the total participant group was 4.2 average grades. Reliability of opticians' eye refraction result and prescription was 50.5%. However consumers wanted to obtain more accurate eye refraction result and prescription with more comprehensive explanations. Also, consumers wanted opticians to be sensitive and have appreciative eye in select spectacles for customers, and to offer precise spectacle dispensing services and courteous after-sales care.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.87-95
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• 2003

Although extensive studies were conduced on hydrogen fermentation of organic wastewaters, little is known about biohydrogen production from organic solid wastes. The leaching-bed reactor treating food waste by heat-shocked anaerobic sludge was, therefore, operated at D of 2.1, 3.6, 4.5 and $5.5d^{-1}$ to find optimal D for hydrogen production. Successful operation of a reactor can be accomplished when it is operated at proper dilution rate (D). Operation at high D leads to the washout of biomass in the reactor while operation at low D leads to product inhibition due to the accumulation of excess VFA. These appear to limit the production of hydrogen to reach a higher level. All the reactors showed that, on day 1-3, hydrogen production was dominant and VFA concentration was higher than ethanol. Butyrate and acetate were major components of VFAs over the whole operation, though lactate was very high on day 1-2. Compared with other D values, D of $4.5d^{-1}$, resulted in higher butyrate/acetae (B/A) ratios during the fermentation. The trend of B/A ratios was similar to the hydrogen production, suggesting that butyrate formation favored hydrogen production. Ethanol increased significantly from day 4 when hydrogen Production stopped. It indicated that heat-shocked sludge was able to induce a metabolic flow from hydrogen-and acid-producing pathway to solvent-producing pathway. Operation at D of $4.5d^{-1}$ led to higher fermentation efficiency (58%) than those (51.5, 55.3 and 53.7%) at 2.1, 3.6 and $5.5d^{-1}$. The COD removed was convened to hydrogen (10.1%), VFA (30.9%), and ethanol (17.0%).

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.923-931
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• 2005

A study was carried out to identify the major causes of sediments pollution in the Paldang Lake in the vicinity of Gyeongan river. Samples from 40 sites were collected and analyzed to characterize the regional distributions of grain size, organic matter contents, and concentrations of T-N, T-P and heavy metals. contaminations. The mean grain size(Mz) ranged from sand type(Mz, $1{\sim}3\;{\phi}$) where Bukhan River and Namhan River converges at a high flow rate to silt type(Mz, $5{\sim}10\;{\phi}$) at the downstream of Gyeongancheon and Paldang lake, reflecting the water circulation in the area. Except sampling point St. 36 near the wetland, the determination coefficient($r^2$) of Mz and organic matter(LOI) was 0.88, showing that more organic matters are concentrated inside finer sediments. The concentrations of T-N and T-P in sediments were higher in the area at which Mz and organic matters are also higher. High concentrations of T-P analyzed in the sediments, ranging from $216{\sim}1,623\;{\mu}g/g$ (Avg. $769\;{\mu}g/g$) could be considered as a critical level. Adsorbed-P and NAI-P, which are easily released to the surrounding environments when physico-chemical characteristics of sediments are changed, was found to be around 20%, which was showed by the result of fractionated-P. Moreover, Principle Component Analysis(PCA), showed that high concentrations of T-N, T-P, organophilic metals (Cd, Cu, Pb, Zn) are distributed in the areas where high organic matter contents and fine grain-sized sediments are found. However, results of $I'_{geo}$ (Geoaccumulation Index) that considers the grain size of sediments showed that heavy metal concentrations in the lake was low enough to be considered as Class 1 indicating the relative degree of pollution was less than zero.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.2
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• pp.87-96
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• 2004

Studies were conducted to select the candidate buffer material for a high-level waste (HLW) repository in Korea. This paper presents the hydraulic properties, the swelling properties, the thermal properties, and the mechanical properties as well as the radionuclide release-retarding capacity of Kyungju bentonite as part of those studies. Experimental results showed that the hydraulic conductivities of the compacted bentonite were very low and less than $10^{-11}$m/s. The values decreased with increasing the dry density of the compacted bentonite. The swelling pressures were in the range of 0.66 MPa to 14.4 ㎫ and they increased with increasing the dry density. The thermal conductivities were in the range of 0.80 ㎉/m $h^{\circ}C$ to 1.52 ㎉/m $h^{\circ}C$. The unconfined compressive strength, Young's modulus and Poison's ratio showed the range of 0.55 ㎫ to 8.83 ㎫, 59 ㎫ to 1275 ㎫, and 0.05 to 0.20, respectively, when the dry densities of the compacted bentonite were 1.4 Ms/㎥ to 1.8 Mg/㎥. The diffusion coefficients in the compacted bentonite were measured under an oxidizing condition. The values were $1.7{\times}10^{-10}$m^2$/s to 3.4{\times}10^{-10}$m^2$/s for electrically neutral tritium (H-3), 8.6{\times}10^{-14}$m^2$/s to 1.3{\times}10^{-12}$m^2$/s for cations (Cs, Sr, Ni), 1.2{\times}10^{-11}$m^2$/s to 9.5{\times}10^{-11}$m^2$/s for anions (I, Tc), and 3.0{\times}10^{-14} $m^2$/s to 1.8{\times}10^{-13}$m^2$/s $for actinides (U, Am), when tile dry densities were in the range of 1.2 Mg/㎥ to 1.8 Mg/㎥. The obtained results will be used in assessing the barrier properties of Kyungju bentonite as a buffer material of a repository in Korea.n Korea.

• Journal of Animal Science and Technology
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• v.49 no.2
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• pp.161-170
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• 2007

A submerged biofilm sequencing batch reactor (SBSBR) process, which liquor was internally circulated through sandfilter, was designed, and performances in swine wastewater treatment was evaluated under a condition of no external carbon source addition. Denitrification of NOx-N with loading rate in vertical and slope type of sandfilter was 19% and 3.8%, respectively, showing approximately 5 times difference, and so vertical type sandfilter was chosen for the combination with SBSBR. When the process was operated under 15 days HRT, 105L/hr.m3 of internal circulation rate and 54g/m3.d of NH4-N loading rate, treatment efficiencies of STOC, NH4-N and TN (as NH4-N plus NOx-N) was 75%, 97% and 85%, respectively. By conducting internal circulation through sandfilter, removal performances of TN were enhanced by 14%, and the elevation of nitrogen removal was mainly attributed to occurrence of denitrification in sandfilter. Also, approximately 57% of phosphorus was removed with the conduction of internal circulation through sandfilter, meanwhile phosphorus concentration in final effluent rather increased when the internal circulation was not performed. Therefore, It was quite sure that the continuous internal circulation of liquor through sandfilter could contribute to enhancement of biological nutrient removal. Under 60g/m3.d of NH4-N loading rate, the NH4-N level in final effluent was relatively low and constant(below 20mg/L) and over 80% of nitrogen removal was maintained in spite of loading rate increase up to 100g/m3.d. However, the treatment efficiency of nitrogen was deteriorated with further increase of loading rate. Based on this result, an optimum loading rate of nitrogen for the process would be 100g/m3.d.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.188-202
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• 1997

The seasonal variability of the sea surface winds over the last Sea of Korea (Japan Sea) is investigated by means of empirical orthogonal function (EOF) analysis. The combined representation of fields of three climatic variables by empirical orthogonal functions is discussed. The eigenvectors are derived from daily sea level pressure, wind speed and 10-day mean sea surface temperature (SST) during 15 years $(1978\~1992)$. The spatial patterns of the mean pressure are characterized by the high pressure in the western part and the low pressure in the eastern part. The spatial distribution of the standard deviation (SD) of pressure are characterized by max SD of 6.6 mb near the Vladivostok, and minima along the coast of the Japan. In Vladivostok, the maxima of SD of SST and south-north wind (WV) were also occurred. The representation of fields of individual meteorological variables by EOF shows that the first mode of the west-east wind (WU) explain over $47.3\%$ of the variance and the second mode of WU represents $30\%$. Especially, the first mode of the WV explain $70.9\%$ of the variance and their time series coefficients show 1-cpy, 0.5-cpy frequency spectrum. The spatial distribution of the first mode eigenvectors of SST are characterized by maximum near Vladivostok. The combined representation of fields of several variables (pressure, wind, SST) reveals that the first mode magnitudes of the variance of the combined eigenvectors (WU-PR) are increased. By means of this result, the 1-year peak and the 6-months peak are remarkable. In the three combined patterns (wind, pressure, SST), the second mode of the eigenvector (wind) is affected by the SST. Their time coefficients of the first mode show noticeable 1-year peak. The spectral analysis of the second mode shows broad seasonal signal with the period of 4-months and a significant peak of variability at 3-month period.

• Journal of Nutrition and Health
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• v.26 no.2
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• pp.131-144
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• 1993

This study was carried out to investigate the effects of different sources and level of dietary lipid on lecithin : cholesterol acyltrasferase activity and cholesterol metabolism in male rats of Sprague-Dawley strain. The effects of different lipid sources was compared with sardine oil($\omega$3 EPA and DHA), beef tallow(SFA), perilla oil($\omega$3 linolenic acid) and corn oil($\omega$6 linoleic acid). Diets were formulated in such a way that 10%, 20% and 40% dietary energy were supplied with each of four experimental lipid sources. Control diet contained only non-lipid energy. A total number of 78 rats, equally divided into 13 groups, were fed the experimental diets for a period of 6 weeks. In vitro cultures were also carried out to study the cholesterol synthetic activity in the liver prepared from rats used in feeding trials. The concentration of plasma total cholesterol, HDL-cholesterol, LDL-cholesterol and HDL-C/T/C(total cholesterol) ratio were significantly (p<0.001) influenced by dietary lipid sources. Higher HDL-cholesterol and lower LDL-cholesterol concentration in plasma were obtained in rats fed $\omega$3 fatty acid supplemented diets(sardine oil and perilla oil group) compared to diets containing $\omega$6 and saturated fatty acid(corn oil and beef tallow group). In total cholesterol concentration of plasma, beef tallow group was significantly (p<0.001) higher than other lipid groups, and non-lipid group was significantly(p<0.05) higher than the lipid supplemented groups. The activity of lecithin : cholesterol acyltransferase(LCAT) in plasma was greatly(p<0.001) affected by dietary lipid sources and levels. In LCAT acivity of plasma, lipid supplemented groups were significantly(p<0.05) higher than non-lipid group, vegetable oil groups were significantly (p<0.001) higher than animal fat groups, and sardine oil group were significalylty (p<0.001) higher than beef tallow group. Also perilla oil group was significanlty (p<0.05) higher than corn oil group, and sardine oil group was significantly (p<0.05) higher than perilla oil group. Low lipid group, compared with medium or high lipid group, showed higher activity of LCAT in plasma. In cholesterol synthetic activity of liver tissues culture, sardine oil group($\omega$3 EPA and DHA) was significantly(p<0.001) higher than other lipid groups, non-lipid group was significantly(p<0.001) higher than the lipid supplemented groups, and amimal fat group were significantly(p<0.001) higher than vegetable oil groups, but the synthetic activity was not affected by dietary lipid levels.