• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.349-354
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• 2023

This study wa s conducted a s pa rt of ma ximizing the use of ca rbon dioxide by a pplying CCU(Ca rbon Ca pture, Utiliza tion) a mong technologies for reducing CO₂ in the cement industry. In a carbon dioxide curing environment, changes in carbonation depth and changes in basic physical properties by age due to the mixing of carbonation reaction accelerators were usually targeted at Portland cement paste. In addition, in order to check the fixed amount of CO₂ in the concrete field, a thermal analysis method was applied to evaluate CaCO₃ decarbonization at high temperatures. As a result of the evaluation, it was confirmed that the carbonation depth in the cured body significantly increased due to the incorporation of CRA in the carbonation depth diffusion performance. In addition, it was confirmed that the weight reduction rate increased by 23.8 % and 40.77 %, respectively, compared to Plain, in the order of curing conditions for constant temperature and humidity and curing conditions for carbonation chambers, so it was confirmed that the amount of excellent CaCO₃ produced by the addition of CRA increased as the concentration of CO₂ increased.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.12-23
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• 2024

In this study, a structural concrete square beam was developed using the centrifugal molding technique. In order to secure the bending stiffness of the cross section, the hollow rate of the cross section was set to 10% or less. Instead of using the current poor mixture of concrete and a concrete mixing ratio with a high slump (150-200) and a design strength of 100 MPa or more was developed and applied. In order to investigate the durability of centrifugally formed PSC square beams to be used as the superstructure of the avalanch tunnel or ramen bridge, the durability performance of ultra-high-strength centrifugally formed concrete with a compressive strength of 100 MPa was evaluated in terms of deterioration and chemical resistance properties.Concrete durability tests, including chloride penetration resistance, accelerated carbonation, sulfate erosion resistance, freeze-thaw resistance, and scaling resistance, were performed on centrifugally formed square beam test specimens produced in 2022 and 2023. Considering the information verified in this study, the durability of centrifugally molded concrete, which has increased watertightness in the later manufacturing stage, was found to be superior to that of general concrete.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.297-302
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• 2017

Recently, building materials and air purification filters with eco-friendly charcoal are actively studying to reduce the concentration of radon gas in indoor air. In this study, radon reduction performance was assessed by designing and producing new panel-type activated carbon filter that can be handled more efficiently than conventional charcoal filters, which can reduce radon gas. For the fabrication of our panel-type activated carbon filter, first the pressed molding product after mixing activated carbon powder and polyurethane. Then, through diamond cutting, the activated carbon filter of 2 mm, 4 mm and 6 mm thickness were fabricated. To investigate the physical characteristics of the fabricated activated carbon filter, a surface area and flexural strength measurement was performed. In addition, to evaluate the reduction performance of radon gas in indoor, the radon concentration of before and after the filter passes from a constant amount of air flow using three acrylic chambers was measured, respectively. As a result, the surface area of the fabricated activated carbon was approximately $1,008m^2/g$ showing similar value to conventional products. Also, the flexural load was found to have three times higher value than the gypsum board with 435 N. Finally, the radon reduction efficiency from indoor gas improved as the thickness of the activated carbon increases, resulting in an excellent radon removal rate of more than 90 % in the 6 mm thick filter. From the experimental results, the panel-type activated carbon is considered to be available as an eco-friendly building material to reduce radon gas in an enclosed indoor environment.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.5
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• pp.591-610
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• 2020

Concrete with activated carbon and titanium dioxide (TiO₂) has been used to reduce the particulate matter (PM) in underground structures (e.g., tunnels) due to the high performance of nitrogen oxides (NOx) abatement. Damage (e.g. crack, spalling, or detachment) can be caused by the environmental and ageing effects on the surface of the particulate matter reduction concrete, installed on the tunnel lining. Therefore, it is important to evaluate the existence of spalling on the concrete surface for maintaining performance of NOx reduction. In this study, a basic research was performed for feasibility of spalling evaluation using electrical resistivity characteristics. Given the test results, the electrical resistivity was decreased as the ratios of activated carbon (0~15%) and TiO₂ (0~25%) were increased for specimens. Under a dry condition, electrical resistivity of cement specimens, mixed with activated carbon and TiO₂, was decreased up to 2.3 times, compared with the normal cement specimen. In addition, under saturation conditions (degree of saturation: 85~98%), electrical resistivity of cement specimens with activated carbon, was decreased up to 3.5 times, compared with the normal cement specimen. Regardless of the condition (dry or saturated), the difference of electrical resistivity values shows the range of 2.3~2.8 times between the mixing specimen (with activated carbon (15%) and TiO₂ (25%)) and the normal cement specimen. This study can help to provide basic knowledge for spalling evaluation using the electrical resistivity on the surface of the particulate matter reduction concrete in tunnels.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.472-487
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• 2020

With the emergence of abnormal climate due to the rapid industrialization, the importance of water quality management and management costs are increasing every year. In Korea, for the management of total phosphorus and total nitrogen, the major materials causing the water quality pollution, coagulants are injected in sewage treatment plants to process organic compounds. However, if the coagulant is injected in an excessive amount to PAC (Poly Aluminium Chloride), a secondary pollution problem might occur. As such, a study on the applicability of natural material-based coagulant is being conducted in Korea. Thus, this study aimed to evaluate the applicability of a mixed coagulant developed by analyzing water quality pollutants T-P, T-N as well as their turbidity, in order to derive the optimum mixing ratio between PAC and torrefied wood flour for the primary settling pond effluent. Under the condition where the content of PAC (10%) and torrefied wood flour is 1%, T-P showed the maximum removal efficiency of 92%, and T-N showed approximately 22%. This indicates that removal of T-N which includes numerous positively charged organic compounds that are equivalent to mixed coagulant is not well accomplished. Turbidity showed the removal efficiency of approximately 91%. As such, 1% of torrefied wood flour was determined to be the optimum addition. As a result of analyzing the removal efficiency for organic compounds by reducing PAC concentration to 7%, T-P showed a high maximum removal efficiency of 91%, T-N showed 32%, and turbidity showed the maximum of 90%. In addition, a coagulation process is performed by using the mixed coagulant based on 1% content of torrefied wood flour produced in this study by performing a coagulation performance comparative experiment with PAC (10%). As a result, PAC concentration was reduced to 30-50%, a similar performance with other coagulants in market was secured, PAC injection amount was reduced that an economic effect can be achieved, and it is considered to perform a stable water treatment that reduces the secondary pollution problem.

• Journal of Agricultural Extension & Community Development
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• v.21 no.1
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• pp.35-82
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• 2014

It was main objectives to find the learners characteristics and educational effects of cyber agricultural technology courses in RDA. For the research, it was followed by literature reviews and internet based survey methods. In internet based survey, two staged stratified sampling method was adopted from cyber training members database in RDA along with some key word as open course or certificate course, and enrollment years. Instrument was composed through literature reviews about cyber education effects and educational effect factors. And learner characteristics items were added in survey documents. It was sent to sampled persons by e-mail and 316 data was returned via google survey systems. Through the data cleaning, 303 data were analysed by chi-square, t-test and F-test. It's significance level was .05. The results of the research were as followed; First, the respondent was composed of mainly man(77.9%), and monthly income group was mainly 2,000,000 or 3,000,000 won(24%), bachelor degree(48%), fifty or forty age group was shared to 75%, and their job was changed after learning(12.2%). So major respondents' job was not changed. Their major was not mainly agriculture. Learners' learning style were composed of two or more types as concrete-sequential, mixing, abstract-random, so e-learning course should be developed for the students' type. Second, it was attended at 3.2 days a week, 53.53 minutes a class, totally 172.63 minutes a week. They were very eager or generally eager to study, and attended two or more subjects. The cyber education motives was for farming knowledge, personal competency development, job performance enlarging. They selected subjects along with their interest. A subject person couldn't choose more subjects for little time, others, non interesting subject, but more subject persons were for job performance benefits and previous subjects effectiveness. Most learner was finished their subject, but a fourth was not finished for busy (26.7%). And their entrying behavior was not enough to learn e-course and computer or internet using ability was middle level as software using. And they thought RDA cyber course was comfort in non time or space limit, knowledge acquisition, and personal competency development. Cyber learning group was composed of open course only (12.5%), certificate only(25.7%), both(36.3%). Third, satisfaction and academic achievement of e-learning learners were good, and educational service offering for doing job in learning application category was good, but effect of cyber education was not good, especially, agricultural income increasing was not good because major learner group was not farmer, so they couldn't apply their knowledge to farming. And content structure and design, content comprehension, content amount were good. The more learning subject group responded to good in effects, and both open course and certificate course group satisfied more than open course only group. Based on the results, recommendation was offered as cyber course specialization before main course in RDA training system, support staff and faculty enlargement, building blended learning system with local RDA office, introducing cyber tutor system.

• (The) Research of the performance art and culture
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• no.32
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• pp.209-241
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• 2016

"Women's Nong-ak (農樂, Traditional Korean music performed by farmers)" was born together with "Maiden group." This study focuses on the reason why women appeared as principal agents of Nong-ak which was almost exclusive to men previously and especially, on the appearance of women Nong-ak Artists who was previously worked in Traditional Drama Troupe. This study empirically deals with details of activities of Maiden's (娘子) Nong-ak troupes and Girls' (少女) Nong-ak troupes through newspaper articles. Women Nong-ak Artists enjoyed popularity with their peculiar attractions. Participating in Nong-ak contests and collecting money for their performances, women Nong-ak Artists learned their skills form masters of Woodo Nong-ak and attracted attention with their colorful costumes. Women of Nong-ak circle especially saw through the trend of the time, expanded their arena of activities and exercised flexibility and ability to react quickly to changing situations while mixing with various genres. In particular, young girls were mobilized to show value and marketability of Korean culture as cultural medium who decorated "Pure Nong-ak art stage." They were no different from "Pretty dolls dancing like angels" who could not purse their interest and economic benefit or incite political cause and their patrons were domestic and overseas political figures. Women artists, who put Nong-ak on the stage in the name of Maiden's (娘子) Nong-ak troupes and Girls' (少女) Nong-ak after the liberation from Japanese colonial rule, contributed to expansion of market base. Women Nong-ak artists, who dominated a century in such troupes as Sadangpae, Hyuprulsa, Maiden's (娘子) Nong-ak troupes, Girls' (少女) Nong-ak troupes and Women Nong-ak troupes, were the very heroines who overturned the conventions of "male predominance (男尊女卑)" which filled Nong-ak arena and cultivated a new tradition of Nong-ak culture.

• (The) Research of the performance art and culture
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• no.42
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• pp.47-75
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• 2021

This thesis looks into the interpretation of the Korean War and mystery genre in Korea in the 1970s by analyzing the special drama , in which the theme was directly related to the Korean War, airing through MBC in 1979. It begins by finding the change in direction in the 1970s when the world of TV was dictated through the heavy censorship and the memory of the war by the government. It also looks at the intentions of the producer who was taking in the new way and the viewers who also accepted this drama and its reflections. In order to gain some insights into these issues, it compares between the drama "The Last Witness" and the original novel by Seong-jong Kim who holds the same time to see the way in which this is dramatized. The drama, "The Last Witness", was produced with a plan to generate a high-quality special drama which combined both artistry and sense of purpose. Nevertheless, as watching TV became a leisurely past-time during this period, TV dramas become more aggressive and suggestive in order to attract viewers. This ultimately was encored with obstacles due to the regime and the heavy censorship at the time. The genre of special drama that is well known in South Korea, is designed as an art form to satisfy both their unique artistry and its purpose. The conflict is seen between the key elements of the artistic drama crated by the producers and the 'encouraged' elements that often are needed to engage the viewers. Thus, more often than not, special dramas defeat the original intention of national harmony, encouraged by the regime. This is due to the 'novelty' aspect which grows from the effort of bringing enjoyment to viewers whilst also trying to achieve the artistic drama to life. Alongside this, crime element in this drama is designed in a way that visually embodies the process of deduction, becoming a new possibility to secure the reality of the times. However, it was also a paradoxical existence since it was indicated as an example of unrefined culture that lost its original intention. In that way, it is worth to think that detective suspense stories, which were not popular in Korea, influenced viewers as a tv drama series in the 1970s through the various elements that compose the genre. They went through a process of transplantation and acceptance whilst also attempting to satisfy the viewers and their encouraged elements to engage them. As is well known, crime drama in Korea has its own style by mixing anticommunism and detective reasoning. This combination is found in the way in which the genre naturally forms through the elements selected and excluded in the dramatization of "The Last Witness". The point is that the special drama "The Last Witness" can be seen as an intermediate form that shows the tendency of transformation from the detective reasoning form alongside the crime aspects as TV dramas began to include anticommunism messaging and investigation in the 1970s. In conclusion, when the detective reasoning is used as an element in a TV drama, it shows the trust of the public system and it constantly seeks the possibility of circumventing the political interpretation. The memories of the war is seen as a tool that neutralizes the dismal imaginations inscribed on the dark side of society and the system. As a result, "The Last Witness", broadcasted at the end of the Yushin regime in Korea, is a strange result which combines the logic of a special drama and the encouraged characteristics of television dramas. The viewers' desire which is the discussion about the hidden traces from the texts needs to be restored again.

• Korean Journal of Poultry Science
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• v.29 no.4
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• pp.271-278
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• 2002

Two experiments were conducted to compare the effects of the natural and synthetic commercial pigments on the laying Performance, Pigmentation and fatty acid contents in e99 yolk of laying hens. The experimental diets were formulated to have isocalories and isonitrogen. In experiment I, the diet does not contain the com in which the xanthophylls are free, and in experiment II, the diet contained 54% of corn in which the level of xanthophylls are 19.34 ppm/kg (calculated levels). In the experiment 1, 480 ISA Brown laying hens were divided into eight groups. Each group has 60 birds fed the 0% of corn with 8 types of pigment levels for 4 weeks. in the experiment 2, 600 ISA Brown laying hens were divided into ten groups. Each group has 60 birds fed the 54% of com diet with 10 types of pigment levels for 4 weeks. Feed intake, e99 Production, egg weight and feed efficiency did not have significant difference in experiments I and II. Albumen height and haugh unit did not have significant difference in both experiments. In order to approach the yolk pigmentation to 12∼13 of Roche color fan, addition level of natural red pigment was 25∼30 ppm. In the case of synthetic red pigment, the level was 15∼20 ppm. In this experimental condition, the pigmenting effect of the synthetic pigment was better than that of the natural pigment. In the experiment 2, the pigmenting effect of mixing pigments were investigated between TM2 mixed with natural red pigment, and TM6 mixed with synthesis red pigment. The pigmenting effect of synthetic red pigment was greater than that of the natural red pigment. However, the pigmenting effect of natural pigment was greater than that of synthetic pigments when the levels of synthetic and natural red pigments in diet are higher in TM3 and TM8. The fatty acid content in yolk was not affected by pigment addition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.129-136
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• 2011

Recently studies on functional concrete with a photocatalytic material such as $TiO_2$ have actively been carried out in order to remove air pollutants. The absorbtion of $TiO_2$ from those studies is applied by it being directly mixed into concrete or by suspension coated on the surface. When it comes to the effectiveness, the former process is less than that of the latter compared with the $TiO_2$ use. As a result, the direct coating of $TiO_2$ on materials' surface is more used for effectiveness. The Surface spread of it needs to have a more than $400^{\circ}C$ heat treat done to stimulate the activation and adhesion of photocatalysis. Heat treat consequently leads hydration products in concrete to be dehydrated and shrunk and is the cause of cracking. The study produces $TiO_2$ used Sol-gel method which enables it to be coated with a low temperature treat, applies it to pearlite using Lightweight Aggregate Concrete fixed with a low temperature treat and evaluates the spread performance of it. In addition to this, the size of pearlite is divided into two types: One is 2.5 mm to 5.0 mm and the other is more than 5.0 mm for the benefit of finding out the removal characteristics of $CH_3CHO$ whether they are affected by pearlite size, mixing method and ratio with $TiO_2$ and elapsed time. The result of this experiment shows that although $TiO_2$ produced by Sol-gel method is treated with 120 temperature, it maintains a high spread rate on the XRF(X ray Florescence) quantitative analysis which ranks $TiO_2$ 38 percent, $SiO_2$ 29 percent and CaO 18 percent. In the size of perlite from 2.5 mm to 5.0 mm, the removal characteristic of $CH_3CHO$ from a low temperature heated Lightweight concrete appears 20 percent higher when $TiO_2$ with Sol-gel method is spreaded on the 7 percent of surface. In other words, the removal rate is 94 percent compared with the 72 percent where $TiO_2$ is mixed in 10 percent surface. In more than 5.0 mm sized perlite, the removal rate of $CH_3CHO$, when $TiO_2$ is mixed with 10 percent, is 69 percent, which is similar with that of the previous case. It suggests that the size of pearlite has little effects on the removal rate of $CH_3CHO$. In terms of Elapsed time, the removal characteristic seems apparent at the early stage, where the average removal rate for the first 10 hours takes up 84 percent compared with that of 20 hours.