• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.152-160
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• 2021

Converter steel slag(BOF slag) is a vast amount of solid waste generated in the steelmaking process which has very low utilization rate in Korea. Due to the presence of free CaO which can derive bad volume stability in BOF slag, it usually land filled. For recycling BOF and identify its applicability as fine aggregate, this study investigates the fundamental characteristics of mortar with cement replaced ferronickel slag(FNS), which has the potential to be used as a binder. The results suggest that the mineral phases of BOF slag mainly include larnite(CaSiO₄), mayenite(Ca₁₂Al₁₄O₃₃) and wuestite(FeO) while olivine crystallines are shown in FNS. The results of flow and setting time reveals that the flowability and process of hardening increased when the amount of FNS and BOF slag incorporated was increased. The length change shows that the amount of change in the length of the mortar was almost constant regardless of mix proportion while compressive strength was reduced. Micro structure test results revealed that FNS or/and BOF slag mix took a long time to react in the cement matrix to form a complete hydration products. To achieve the efficient utilization of B OF slag as construction materials, proper replacement rate is necessary.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.789-792
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• 2008

Blast furnace slag doesn't have self-hydraulicity and it needs stimulants such as alkali to hydrate. Therefore using recycled aggregates erupted calcium hydroxides and blast furnace slag acquiring alkali stimulate could make a complementarily use of a recycling architectural material possible. In this study, we have discussed about characters of blast furnace slag and recycled aggregate firstly, and make recycled aggregate mortar and concrete using blast furnace slag for the experiment. The experiment is about mortar and concrete using recycled aggregate as a substitutional material of blast furnace slag. In this experiment, I replace blast furnace slag and aggregate with recycled aggregate. Conclusions through the test results analysis are as follows. And then, we added field experiment using concrete with composited materials.

• Economic and Environmental Geology
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• v.46 no.3
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• pp.267-278
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• 2013

The East African Rift System(EARS) is known to be hosted epithermal Au-Ag deposits, and the best-known example is Main Ethiopian Rift Valley(MER) related to Quaternary bimodal volcanism. Large horst-graben system during rifting provides open space for emplacement of bimodal magmas and flow channel of geothermal fluids. In recent, large hydrothermally altered zones(Shala, Langano, and Allalobeda) and hot spring related to deeply circulating geothermal water have been increasing their importance due to new discoveries in MER and Danakil depression. The hot springs in Shala and Allalobeda occur as boiling pool and geyser on the surface, whereas some areas didn't observe them due to decreasing ground water table. The host rocks are altered to quartz, kaolinite, illite, smectite, and chlorite due to interaction with rising geothermal water. The hot springs in MER are neutral to slightly alkaline pH(7.88~8.83) and mostly classified into $HCO_3{^-}$ type geothermal water. They are strongly depleted in Au, and Ag, but show a higher Se concentration of up to 26.7 ppm. In contrast, siliceous altered rocks around hot springs are strongly enriched in Pb(up to 33 ppm, Shala), Zn(up to 313 ppm, Shala), Cu(up to 53.1 ppm, Demaegona), and Mn(up to 0.18 wt%t, Shala). In conclusion, anomalous Se in hot spring water, Pb, Zn, Cu, and Mn in siliceous altered rocks, and new discoveries in MER have been increasing potential for epithermal gold mineralization.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.303-308
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• 2011

Background/Aims : The increasing use of diagnostic and therapeutic interventional radiology calls for greater consideration of radiation exposure risk to radiologist and radiological technician, and emphasizes the proper system of radiation protection. This study was designed to assess the effect of a protective grass shield. Methods : A protective grass was following data depth, 0.8 cm; width, 100 cm; length, 100 cm, lead equivalent, 1.6 mmPb. The protective shield was located between the patient and the radiologist. Thirty patients (13 male and 17 female) undergoing interventional radiology between September 2010 and December 2010 were selected for this study. The dose of radiation exposure was recorded with or without the protective grass shield at the level of the head, chest, and pelvis. The measurement was made at 50 cm and 150 cm from the radiation source. Results : The mean patient age was 69 years. The mean patient height and weight was $159.7{\pm}6.7$ cm and $60.3{\pm}5.9$ kg, respectively. The mean body mass index (BMI) was $20.5{\pm}3.0$ kg/m2. radiologists received $1530.2{\pm}550.0$ mR/hr without the protective lead shield. At the same distance, radiation exposure was significantly reduced to $50.3{\pm}85.2$ mR/hr with the protective lead shield (p-value<0.0001). The radiation exposure to radiologist and radiological technician was significantly reduced by the use of a protective lead shield (p value <0.0001). The amount of radiation exposure during interventional radiology was related to the patient' BMI (r=0.749, p=0.001). Conclusions : This protective shield grass is effective in protecting radiologist and radiological technician from radiation exposure.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.91-109
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• 2022

The ocean is a significant sink for atmospheric anthropogenic CO₂, absorbing one-third of the total CO₂ emitted by human activities. In return, oceans have experienced significant declines in seawater pH and the aragonite saturation state also called ocean acidification. This study evaluates the distribution of aragonite saturation state, an indicator to assess the potential threat from ocean acidification, by combining newly obtained data from the west coast of South Korea with previous datasets covering the Yellow Sea, East Sea, northern South China Sea, and southeast coast of South Korea. In general, offshore waters absorb atmospheric CO₂; however, most of the collected water samples show aragonite oversaturation. On the southeast coast, the aragonite saturation state was significantly affected by river discharge and associated variables, such as freshwater input with nutrients, seasonal stratification, biological carbon fixation, and bacterial remineralization. In summer, hypoxia and mixing with relatively acidic freshwater made the Jinhae and Gwangyang Bays undersaturated with respect to aragonite, possibly threatening marine organisms with CaCO₃ shells. However, widespread aragonite undersaturation was not observed on the west coast, which receives considerable river water discharge. In addition, occasional upwelling events may have worsened the ocean acidification in the southwestern part of the East Sea. These results highlight the importance of investigating site-specific ocean acidification processes in coastal waters. Along with the above-mentioned seasonal factors, the dissolution of atmospheric CO₂ and the deposition of atmospheric acidic substances will continue to reduce the aragonite saturation state in Korean waters. To protect marine ecosystems and resources, an ocean acidification monitoring program should be established for Korean waters.

• Cartoon and Animation Studies
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• s.48
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• pp.141-172
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• 2017

The film (2000) and (2016) are based on different time slips from each other. However, these two films have many common elements that make one illusion-based illusion. In the common elements, the main characters (being and thing) are traversed at different times and directed as a cyclical one. Also, among these, the movement link of the time and space has a commonality that it becomes possible through a medium ( - radio, you, there - pill). As a result, a series of scenes expressed in showed that the scene of produced in 2000 was greatly circulated. The reason why two movies have similar structure is that the basic framework of video media based on time slip is similar. Therefore, the purpose of this study is not to analyze the problem of quoting and borrowing of two films as mentioned in the paper. To add up, the material of video media is manifold which is a dynamic object of potential which is unlimited and opened, and by rearranging one media it can be created by escaping from one territory. Also, it is a study of analysis to contribute to producer or researcher as a time slip video creation reference connecting times based on the manifold arrangement from two films.

• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.353-358
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• 2013

Recently, the Percutaneous Coronary Intervention has become a main treatment for treating Coronary because of increase of Circulatory Disease. Because of this reason, the increase of intervention using radiation causes the radiation exposure to workers. Therefore, the latent radiation injury can be increased. Thus, this study/experiment measured around under knee whether using radiation collimator shielding or not. We measured the exposure does by the experiment methods which are using 60kV, 200mA, and 10ms of Automatic exposure conditions and using the major method of the Cinefluography of Coronary in our hospital. As the result of right coronary artery test cases, LAO $30^{\circ}$ when the curtains if you use lead 98.4%, $Cranial30^{\circ}$ 98.3% have a protective effect of the radiation. left circumflex coronary artery test cases, Caudal $30^{\circ}$ if the shielding effect of 90.2%, Caudal $30^{\circ}LAO$ $30^{\circ}$ 88.7% have a protective effect of the radiation. left anterior descending artery test cases, Cranial $30^{\circ}$ 98.3%, Cranial $30^{\circ}RAO$ $30^{\circ}$ 80.3%, Cranial $30^{\circ}$LAO $30^{\circ}$ 98% of the radiation has a protective effect. OS(Spider view) in the case of test Caudal $40^{\circ}LAO$ $40^{\circ}$ 71.2% appeared to have the effect of radiation shielding. For these reasons, radiation workers need to be aware on taking care of their radiation exposure by using the radiation collimator shielding even though it is uncomfortable for them.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.1
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• pp.33-39
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• 1999

In order to understand the importance of tidal action and $NH_4{^+}$ -nitrification in the removal of dissolved oxygen (DO) and $NH_4{^+}$, concentrations of DO, $NH_4{^+}$, $NO_2{^-}$ and $NO_3{^-}$ were measured with time for water samples collected at different tidal state in the eutrophic macrotidal Han River estuary. Field measurements indicated that most environmental parameters, except for the water temperature and DO concentration, were tightly controlled by the eutrophic freshwater runoff and large-scale tidal action. Dark incubation of the water sample at $25^{\circ}C$ showed that the removal rates of DO and $NH_4{^+}$ in high tide sample were 2.76 ${\mu}M\;O_2\;d^{-1}$ and 1.76 ${\mu}M\;N\;d^{-1}$ respectively, and increased to 5.66 ${\mu}M\;O_2\;d^{-1}$ and 3.36 ${\mu}M\;N\;d^{-1}$ respectively, in low tide sample. These changes indicated that microbial degradation and uptake of organic matter and inorganic nutrients were more active during low tide. $NH_4{^+}$-nitrification responsible for total DO removal in low tide (23.81%) and $NH_4{^+}$ turnover rates due to $NH_4{^+}$-nitrification in low tide (0.18 $d^{-1}$) were approximately 3.7 times and 3 times, respectively, higher than those in high tide. These results indicated that $NH_4{^+}$ -nitrifying bacteria introduced into the Han River estuary during low tide played a significant role in the removal of DO and $NH_4{^+}$. The decreasing removal rates in DO and $NH_4{^+}$ with the increasing tidal level seemed to be associated with the salinity impact on the halophobic freshwater $NH_4{^+}$-nitrifying bacteria. The results implied that anthropogenic $NH_4{^+}$ sources should be treated prior to the freshwater runoff into the estuary for the effective control of $NH_4{^+}$ in the Han River estuary. These results also suggest that parallel ecological studies on the chemoautotrophic nitrifying bacteria are essential for the elucidation of nitrogen cycles in the eutrophic Han River estuary.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.136-143
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• 2006

The study was carried out to evaluate odor emission during storage time and quality of liquid slurry fertilizer along with three storage container types installed at farmer's fields in Cheorwon. Liquid slurry manure stored in the liquid-circulated or the air-injected tank was very homogeneous in concentration of nutritional elements because of well mixing operation, while nutritional concentration of the manure stored in the non-treated tank was significantly different from top to bottom in the tank, which may bring about partially irregular growth of plant after its application. The potential capacity of offensive odor emitted from liquid slurry manure stored in the liquid-circulated or the air-injected tank was much lower than that emitted from manure stored in the non-treated tank. Low potential capacity may less emit offensive odor after application of piggery liquid slurry on the field. The efficiency in oder to reduce odor emission from liquid manure was slightly higher in the liquid-circulated tank than the air-injected tank

• Asia Marketing Journal
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• v.7 no.1
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• pp.21-42
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• 2005

Customer Relationship Management (CRM) is a corporate marketing strategy maintaining and managing customers. And with CRM companies maximize the customer's value through a series of processes of new customer retention, VIP customer retention, customer value increase, potential customer activation, and customers for lifetime by collecting the customer information and taking advantage of it effectively. In particular, as the competitive environment is changing rapidly and getting more intense, maintaining the customer retention through customer churn management becomes more important in order to increase the customer value for maximizing the company's profit and to build up the relationship with customers. For example, the financial industry has managed the customer churn with the concept of customer segmentation. Recently the customer retention and churn management is becoming increasingly important in all business fields as well as financial industry since the companies expect the effect of preventing the customer churn by identifying characteristics of customers. However, despite the increasing interest and importance of the management of the customer churn, not many of studies are systematically executed by analyzing the data of customer churn. In this study we analyze the actual data of CRM activities for the customer retention, specifically the data of TV home-shopping. By doing so, we hope to identify the differences of demographic attributes and transaction specific characteristics in consumer behaviors between the churning customer and the retained customers. In addition, we try to find out the variables which can impact the churning of the customers and to predict the churn rate of individual customer through our proposed model of customer churn. In the end, based on our findings we suggest the possible marketing strategies for TV home-shopping companies.