• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.39-50
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• 2017

In the coagulation/sedimentation (C/S) process of the water treatment process, the inflow of massive algal bloom causes many problems including fouling of filter media. This study was conducted to find out the way to remove the algae's harmful effects by addition of pre-treatment prior to C/S process. Many Jar-tests were conducted such as (1) ACF (Algae Coagulation Flotation) process using natural algae coagulant (Water $Health^{(R)}$), (2) ACF + C/S process and (3) C/S process with a variety of conditions using cultured algae. The average values of turbidity were (1) 0.42 NTU for ACF process, (2) 0.13 NTU for ACF + C/S process and (3) 0.25 NTU for C/S process. It was shown that the treatment efficiency of ACF process could get low turbidity results, and ACF + C/S process could achieve more efficient results than those of C/S process. Any negative effects of ACF process to the efficiency of C/S process were not observed in ACF + C/S process. In order to reduce the unfavorable effects of algae, it was found out that the introduction of ACF process in the forms of (1) ACF or (2) ACF + C/S could be one of the effective and alternative solutions.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.125-136
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• 2013

Director Choi Donghoon is the most famous director in Korea as a box office successor, especially (2102) has gained No. 1 box office attraction in Korean film history. However some critics have criticised the works of Dr. Choi because of their plebeianness. This paper focused on the reason of interaction with audiences through the theory of carnival of Mikhail M. Bakhtin. Because the theory of carnival is not only the adapted method to account for the power of popular culture to M. Baktin but also the useful method to understand the keys of interaction of Dr. Choi's films. It's not difficult to find the esthetic elements of carnival theory example for 'dethronement & coronation', 'overturn & ridicule', 'image of feast', 'language of square' in the films of Choi which are The Big Swindle(2004), Tazza: The High Rollers(2006), Woochi(2009), The Thieves(2012). Therefore this paper has endeavored that the box office attraction and success of communication with audiences is due to the realistic attitude and social reflection of Choi's films.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.577-586
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• 2017

One of the major sources causing eutrophication and algal blooms of lakes or streams is phosphorus which comes from point and nonpoint pollution sources. HAP (hydroxyapatite) crystallization using granular alkaline materials can achieve the decrease of phosphorus load from wastewater treatment plants and nonpoint pollution control facilities. In order to induce HAP crystal formation, continuous supply of calcium and hydroxyl ions is required. In this research, considering HAP crystallization, several types of lime-based granular alkaline materials were prepared, and the elution characteristics of calcium and hydroxyl ions of each were analyzed. Also, column tests were performed to verify phosphorus removal efficiencies of granular alkaline materials. Material_1 (gypsum+cement mixed material) achieved the highest pH values in the column tests consistently, also, Material_2 (gypsum+slag mixed material) and Material_3 (calcined limestone material) achieved over pH 9.0 for 240 hours (10 days) and proved the efficiencies of long-term ion supplier for HAP crystallization. In the column tests using Material_3, considerable pH increase and phosphorus removal were carried out according to each linear velocity and filtration depth. T-P removal efficiencies were 87.0, 84.0, 68.0% and those of PO4-P 100.0, 97.0, 80.0% for linear velocity of 1.0, 2.5, 5.0 m/hr respectively. Based on the column test results, the applicability of phosphorus removal processes for small-scale wastewater treatment plants and nonpoint pollution control facilities was found out.

• Journal of Digital Convergence
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• v.15 no.8
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• pp.375-381
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• 2017

The America film, Beauty and Beast has grossed over 4,273,401 after being released for 21 days. The growth of movie profit in the video market is also developing rapidly. In this paper, we will focus on the PLF(Premium Large-Format) video technology, because PLF video technology can help audience to enhance the sense of 'immersion' and enjoy a different visual feast. In PLF video technology, IMAX, screen X, 360 degrees circular screen are the most important formats. By comparative analysis of these 3 formats, the biggest difference is their number of screens and appearance. Based on the result we can understand the 3 kinds of PLF platforms better and help us to make a choice between them. In addition, further research about the manufacture method of PLF technology will be discussed.

• Journal of Engineering Education Research
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• v.14 no.4
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• pp.39-47
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• 2011

This paper deals with nanoethics as a sort of extension of engineering ethics utilizing various books, articles, and reports concerning historical, social, and ethical aspects of nanotechnology. After a brief examination on the place and development process of nanotechnology, ethical issues on nanotechnology are analysed including safety problem, impact on environment, violating privacy, social inequity, military use, and human enhancement. The basic principles on nanoethics are proposed such as promotion of public understanding, construction of participatory governance, contribution to sustainable development, commitment to precautionary principle, and compliance with research integrity. Lastly, integrated method in nanoethics education is illustrated putting lecture model, investigation model and discussion model together. This paper can provide the contents available for nanoethics education, and make a basis for the sound development of nanotechnology.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.401-401
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• 2022

우리나라 대규모 하수처리장에 상용화되어있는 응집공정의 운영상 난점을 극복하고자 대체공정으로 고안된 인 결정여과공정(HCF, Hydroxyapatite Crystallization-Filtration process)의 pilot plant를 구축하고 부산슬러지의 자원화를 위해 그 특성을 검토하였다. 기존의 hydroxyapatite(HAP) 결정화공정 내 탈탄산(decarbonation) 단계를 생략하는 HCF공정의 경우에 고농도의 Ca²⁺ 주입과 처리수내 탄산염으로 인해 HAP을 포함하는 석회계 슬러지가 발생하는데, 이는 산성화된 토양의 개량제(중화제)로 널리 사용될 수 있다. 본 연구를 위해 경기도 I하수처리장 2차침전지 후단에 구축된 처리용량 27.1 - 135.6 m³/day HCF pilot plant의 전처리 조건은 pH 10.0 - 11.0, Ca²⁺ 농도 80 mg/L이었다. 결정여과조는 선속도 1.0 - 5.0 m/hr, 상향류로 운전되며, 여재는 2.0 - 3.0 mm의 석회석 모래를 충전하였다. 역세척은 중앙에 Air lifting pipe를 설치하여 역세척수가 처리수와 분리배출되도록 설계하였고, 침전시켜 역세척 슬러지를 회수하였다. 처리수의 평균 T-P, PO₄-P 및 SS는 각각 0.05, 0.04, 1.1 mg/L으로 모든 항목에서 방류수 수질기준 이하로 안정적으로 유출되었다. 회수된 HCF 슬러지는 SEM-EDX, XRD, FT-IR을 활용하여 그 특성을 분석하였다. SEM-EDX로 분석된 슬러지의 원자분율은 CaCO₃ 또는 HAP으로 추측되었다. 또한, XRD spectrum 분석결과, 슬러지의 주요 구성성분은 calcite, HAP, phosphoric acid(H₃PO₄) 및 brusite로 나타났다. FT-IR 분석결과, 슬러지는 대부분 인산염 및 탄산염의 무기물로 구성되어 있으며, 유입수의 인 농도가 높을수록 슬러지 내 HAP의 함량이 calcite보다 높은 것으로 나타났다. 고농도의 Ca²⁺을 주입하여 탈탄산단계를 생략한 HCF의 부산슬러지는 HAP 이외에도 CaCO₃와 칼슘-인 화합물로 구성되어 있는 것으로 나타났다. 하수 인 고도처리를 위한 HCF공정의 하수처리시설 인 고도처리 적용이 검증되었으며, 부산슬러지를 산성화된 토양의 개량제(중화제) 또는 비료로서의 재활용 및 자원화 가능성이 시사되었다.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.743-748
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• 2022

The initial operation stability of hydrogen-fueled, solid oxide fuel cell with Ni thin-film anode fabricated by direct current sputtering was evaluated in terms of electrochemical properties such as peak power density, open circuit voltage, overpotential, and alternating current impedance at 500℃. Hydrogen and air were used as anode fuel and cathode fuel, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.9
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• pp.482-496
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• 2016

Algal blooms of cyanobacteria (blue-green Algae) due to the eutrophication of rivers and lakes can cause not only the damage by its biological toxins but also the economic loss in drinking water treatment. The natural algae coagulant, a commercial product known as W.H. containing the algicidal and allelopathic material derived from oak, can control algal problems proactively through the coagulation flotation process. However, because there have been no applications of the process for pre-treatment in drinking water plants, we could find no report on the optimum injection dose of W.H.. In this study, we have conducted several sets of jar-tests while changing W.H. dose and concentration of chl-a for (1) Han-river samples and (2) subcultured cyanobacteria samples, and monitored the removal mechanisms of algae intensively. Based on these jar-test results, two linear equations with variables of chl-a and turbidity have been deduced to predict the optimal W.H. dose after the multiple regression analysis using IBM-SPSS. Also, prototypes of automatic control logic have been suggested to inject the optimal W.H. dose promptly in response to the variation of water quality.

• Economic and Environmental Geology
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• v.14 no.2
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• pp.93-102
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• 1981

Studies of model potential fields continued upward and downward show differences depending on the method of continuation. Beginning with a magnetic field computed over a buried vertical cylinder, the field was continued to various levels by a method introduced by Henderson (Lagrangian interpolation) and by a spectral method (frequency domain analysis). Resultant fields show (1) no significant differences in upward continued values, (2) in downward continuation, accurate values are obtained with the spectral method over the central part of the anomaly, and (3) accurate values are obtained with Henderson's method on the flanks of the anomaly, while oscillations usually characterize the spectral method in this region. Essentially the same observations are made for derivative calculations. Field oscillations are empirically predicted at levels continued to approximately two-thirds of the depth of the source. Our spectral computer program output yields marked oscillations at one-half of the depth of the source. Henderson's method shows no oscillations at this depth and only minor oscillations at the top of the body (some negative values appear on the flanks of the anomaly). The Henderson output is a smooth field even if continued below the top of the body. These results suggest that the presence of oscillations cannot be used to identify the top of a buried source without careful consideration of the method used to continue the field. Use of the derivative to outline and isolate anomalies must similarly include consideration of the method of calculation.

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.306-319
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• 2012

The purpose of this study was to investigate high school students' learning style, perception of types of laboratory instruction, and the relationship between the learning style and preferred type of laboratory instruction. The participants of this study were 19 female high school students, from Incheon in Korea, who showed outstanding science grades. Dunn et al's revised Learning Styles Inventory (1997) was used for testing students' learning style. The students were asked to choose preferred and not preferred types of experiments and describe the reason of the choices after implementation of 4 types of experiments: verification, discovery, explorator, and investigation laboratory instructions. The findings of this study were as follows: Firstly, the students had a certain common learning style irrelevant to their personal characteristics, i. e; they showed high (self, teacher, parents) motivation and structure stimuli that was common in Korean students. Second, outstanding students prefer unstructured and open laboratory instructions. And those students were highly influenced by sociological and emotional stimuli. Third, students' learning style was related to their preferred type of laboratory instruction. Students preferring unstructured and open laboratory were influenced by sociological and emotional stimuli, while those preferring structured and closed laboratory were influenced by physiological stimuli.