• Journal of the Korean association of regional geographers
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• v.13 no.4
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• pp.409-421
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• 2007

The purpose of this paper is to consider the formation processes and depositional conditions of bars formed at the upper-stream part of Sayeon Dam since Sayeon Dam construction in 1964. Results of analyzing the shape characteristics of bars and their sediment grain size distribution are as follow: Firstly, bars are able to categorized as subaqueous bars (A, B), mid-channel bars(C, D), and tributary side-bars(E). Secondly, the outline of bars has longish along the flow path, and their height lowers more and more going towards downstream. Also the height of bar surface tend to heighten from flow path to mountain slope. However, the near part of A is comparatively higher than its distant part, A is defined as a subaqueous natural levee and back swamp. Thirdly, the average particle size of A and B become smaller toward mountain slope. In transportation style, ratio of suspended load become higher toward mountain slope. Fourthly, sorting is worse to very worse according with lake's random changable water level. Fifthly, bar A and B were formed by vertical sedimentation of sediments according as sediments transported along flow path in the subaqueous conditions were spreaded out of flow path. C and D were formed by bed load as flood level lowered. And E was formed by vertical sedimentation while stream flow stopped in tributary's mouth areas with the water level heightening.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1A
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• pp.11-18
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• 2012

This paper deals with the numerical determination of the stress intensity factors of cracked aluminum plates under the mixed mode of $K_I$ and $K_{II}$ in glass-epoxy fiber reinforced composites. For the stress intensity factors, two different models are reviewed such as VCCT and two-step extension method. The p-convergent partial layerwise model is adopted to determine the fracture parameters in terms of energy release rates and stress intensity factors. The p-convergent approach is based on the concept of subparametric element. In assumed displacement field, strain-displacement relations and 3-D constitutive equations of a layer are obtained by combination of 2-D and 1-D higher-order shape functions. In the elements, Lobatto shape functions and Gauss-Lobatto technique are employed to interpolate displacement fields and to implement numerical quadrature. Using the models and techniques considered, effects of composite laminate configuration according to inclined angles and adhesive properties on the performance of bonded composite patch are investigated. In addition to these, the out-of-plane bending effect has been investigated across the thickness of patch repaired laminate plates due to the change of neutral axis. The present model provides accuracy and simplicity in terms of stress intensity factors, stress distribution, number of degrees of freedom, and energy release rates as compared with previous works in literatures.

• Korean Journal of Environment and Ecology
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• v.25 no.6
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• pp.846-852
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• 2011

This study researched the spawning sites of Kaloula borealis in a large number of wetlands in Jeju Island between May and August from 2007 to 2010. Based on the surveys, we discovered the locations of their habitats by investigating their calls from a rainy night to the next day and where their spawning sites were by ascertaining the existence of their eggs and tadpoles. According to the results, 83 wetlands were used as spawning sites across Jeju Island. A large number of wetlands were found to be permanent wetlands for Kaloula borealis. In addition, 81.9% of the wetlands in Jeju Island were found to be at an altitude of 150m or lower, and they spawned in shallow water not more than 50cm in depth. By region, 54 wetlands were in Jeju-island 29 wetlands were in Seogwipo-si. One of the reasons that Seogwipo-si has less wetlands than Jeju-si is that there are more orchards in Seogwipo-si than Jeju-si; accordingly, wetlands in Seogwipo-si were found to be more destroyed by farming. In the case of Seongsan-eup, a reedy marsh stretches out widely so that spawning sites were well preserved compared to other regions. This research will provide useful data for sustaining the population of Kaloula borealis by protecting their spawning sites from development, by offering habitats, and restoring spawning sites, which have become severely damaged and destroyed.

• Korean Journal of Environment and Ecology
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• v.34 no.5
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• pp.372-395
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• 2020

This study aimed to elucidate the distribution of vascular plants in Mt. Goryeo in Ganghwa-gun, Korea. The results of 14 field surveys from March 2018 to August 2019 identified 629 total taxa, representing 568 species, 10 subspecies, 45 varieties, two forms, and four hybrids in 371 genera and 112 families. The plant formation of Mt. Goryeo is the deciduous broad-leaved and conifer mixed forest, which is the common one in the middle part of the Korean Peninsula. Most parts of the mountain are covered with a young secondary forest, mainly composed of Quercus and Pinus spp. Out of the 629 taxa, 314 were first recorded in the region, six were endemic to Korea, four were listed on the Korean Red List of threatened species, 63 were floristic target plants, and 58 were invasive alien plants. The percentages of the naturalized index (NI) and urbanization index (UI) were 9.2% and 15.5%, respectively. The area showed a high plant diversity with many rare plants and phytogeographically important plants. This study discussed in detail conservation strategies to ensure biodiversity and effective management of Mt. Goryeo. The study results can be used as the reference for the preparation of biodiversity conservation and the establishment of management measures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.386-394
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• 2017

The purpose of this study was to investigate how employed dental hygienists (graduates) and alumni are aware of dental health insurance and how to organize their classes for running efficient dental health insurance courses, and therefore to suggest opinions on the introduction of professional dental hygienist qualifications. The analyses was carried out using IBM SPSS Statistics 24.0. Sixty-nine students (56.1%) preferred one semester dental health insurance course as two semester courses and 63 students (51.2%) preferred theoretical course as practical course. Ninety-six (78%) students preferred dental health insurance claimants as others for their most necessary certification. Ninety-three dentists (75.6%) thought of the dental hygienist as the appropriate occupation for dental health insurance claims. The correlation coefficient was significant at the 0.01 level (both sides) and all showed a positive correlation. The effect of subjective understanding of dental health insurance and the perception of dental health insurance claim on students' intention to complete those courses explained 32% of the response, and the effect of the intention to complete those courses on the willingness to earn a certificate explained 22.3%. This study reveals the willingness of students to complete those courses to acquire qualifications in order to achieve a competitive advantage in employment, and suggests the necessity of institutional improvements such as changing the method of dental insurance education, varying the class time distribution, and introducing dental health insurance professional dental hygienist qualification in the country.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.807-813
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• 2014

The Ag-impregnated activated carbon was produced from bamboo activated carbon by soaking method of silver nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. Soaking conditions are the variation of silver nitrate solution concentration (0.002~0.1 mol/L) and soaking time (maximum 24 h). The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20{\sim}850^{\circ}C$) and NO gas partial pressure (0.1~1.8 kPa). As results, Ag amounts are saturated within 2h, Ag amounts increased 1.95 mg Ag/g (0.2%)~ 88.70 mg Ag/g (8.87%) with the concentration of silver nitrate solution in the range of 0.002~0.1 mol/L. The specific volume and surface area of bamboo activated carbon of impregnated with 0.2% silver were maximum, but decreased with increasing Ag amounts of activated carbon due to pore blocking. In NO reaction, the reaction rate of impregnated bamboo activated carbon was retarded as compare with that of bamboo activated carbon. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.69l[BA(Ag)] and 80.5 kJ/mol[BA], 66.4 kJ/mol[BA(Ag)], respectively.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.955-960
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• 2006

Catalytic decomposition over HZSM-5 was carried out in semi-batch reactor to recover gasoline from waste plastics(HDPE). To enhance the liquid yield with a molecule range of gasoline, the properties of catalytic decomposition were investigated over a commercial Si/ZSM-5 catalyst and HZSM-5 catalysts modified with P and Mg. Optimum loadings of P and Mg on HZSM-5 were 0.5 wt% and 2.0 wt%, respectively, based on conversion and liquid yield. $NH_3-TPD$ profile indicated that strong and weak acid sites totally decreased in P loading on HZSM-5 catalyst, strong acid sites moderately decreased and weak acid sites sharply reduced in Mg loading on HZSM-5 catalyst. In the case of Si/ZSM-5 catalyst, all acid sites almost disappeared, subsequently, catalytic decomposition significantly decreased, and little liquid product was produced. When HZSM-5 catalyst was modified with P and Mg, the carbon distribution of liquid product was shifted to lower carbon number and its all components was within a molecular range of gasoline($C_5-C_{11}$). Especially, over Mg(2.0 wt%)/ZSM-5 catalyst, 55.8% of liquid yield with 100% of a molecular range of gasoline, was obtained at $400^{\circ}C$, suggesting it as a promising catalyst for recycle of waste plastics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.767-773
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• 1994

The dietary fiber intakes of Korean were estimated based on the data from the National Nutrition Survey in 1989. From the data, 566 foods which contain dietary fiber were selected.The intake estimation was done based on these foods. Results were summarized as followed ; Mean DF intake of nationwide population was 17.53g/day and most of these were come from vegetables. Mean DF intake of rural population was slightly lower than that of urban's. Major sources of DF were vegetables, cereals & grain products, seaweeds, fruits, fungi & mushrooms and legumens & their products in order. Vegetables were the major sources of DF which occupied 32.4% of total intake. Among them, kimchi and red pepper were the representative sources. Among cereals & grain products, rice was found to be the most important DF source occupying 12.2% of total DF. And fried noodle, loaf bread and barley were followed. Sea mustard among seaweeds, apples and persimmons among fruits, oyster mushroom and mushroom among fungi & mushrooms and soybean sprout among legumes & their products were favorable sources of DF. 653 households out of 1, 925(33.9%) were consummed 10~15g of DF per day.

• Journal of the Korean Electrochemical Society
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• v.7 no.3
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• pp.131-137
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• 2004

Sol-gel method which provides better electrochemical and physiochemical properties compared to the solid-state method was used to synthesize the material of $LiFe_yMn_{2-y}O_4$. Fe was substituted to increase the structural stability so that the effects of the substitution amount and sintering temperature were analyzed. XRD was used for the structural analysis of produced material, which in turn, showed the same cubic spinel structure as $LiMn_2O_4$ despite the substitution of $Fe^{3+}$. During the synthesis of $LiFe_yMn_{2-y}O_4$, as the sintering temperature and the doping amount of Fe(y=0.05, 0.1, 0.2)were increased, grain growth proceeded which in turn, showed a high crystalline and a large grain size, certain morphology with narrow specific surface area and large pore volume distribution was observed. In order to examine the ability for the practical use of the battery, charge-discharge tests were undertaken. When the substitution amount of $Fe^{3+}\;into\;LiMn_2O_4$ increased, the initial discharge capacity showed a tendency to decrease within the region of $3.0\~4.2V$ but when charge-discharge processes were repeated, other capacity maintenance properties turned out to be outstanding. In addition, when the sintering temperature was $800\~850^{\circ}C$, the initial capacity was small but showed very stable cycle performance. According to EVS(electrochemical voltage spectroscopy) test, $LiFe_yMn_{2-y}O_4(y=0,\;0.05,\;0.1,\;0.2)$ showed two plateau region and the typical peaks of manganese spinel structure when the substitution amount of $Fe^{3+}$ increased, the peak value at about 4.15V during the charge-discharge process showed a tendency to decrease. From the previous results, the local distortion due to the biphase within the region near 4.15V during the lithium extraction gave a phase transition to a more suitable single phase. When the transition was derived, the discharge capacity decreased. However the cycle performance showed an outstanding result.

• Korean Journal of Food Science and Technology
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• v.6 no.2
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• pp.75-78
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• 1974

An experiment has been carried out in order to analyze the main components of Korean Cattles' milk, and fractionate the milk protein by DEAE-cellulose column. The results obtained were summarized as follow. 1) The average values of specific gravity, pH and acidity of Korean Cattles milk which were negative in alcohol test were 1,036, 6.4 and 0.21, respectively. 2) The average values of total solids, solids-not-fat, protein, lactose and ash contents of Korean Cattles milk were 11.61%, 9.53%, 2.08%, 3.99%, 4.76% and 0.86%, respectively. 3) Distribution of casein, whey protein, N.P.N., protein precipitated in 12% TCA, lactoglobulin and lactalbumin contents of the milk were 3.07%, 1.13%, 0.10%, 4.06%, 0.34% and 0.66%, respectively. 4) Acid casein obtained from Korean Cattles milk was fractionated into four fractions on DEAE-cellulose column with 0.005M tris-citrate buffer containing 6M urea, pH 8.6, and the ratio of the fraction I, II, III and IV was 3.24%, 52.67%, 26.22% and 17.87%, respectively. 5) Whey protein obtained from Korean Cattles milk was also fractionated into four fractions on DEAE-cellulose column with 0.04M phosphate buffer, pH 5.8, and the ratio of the fraction I, II, III and IV was 41.74%, 10.17%, 1.50% and 46.59%, respectively.