• Korean Journal of Environment and Ecology
• /
• v.32 no.4
• /
• pp.413-424
• /
• 2018

The study analyzed the effects of topographic structures and altitude in mountainous parks in Mt. Namsan in Gyeongju on the generation of anions. The temperature was at ridge ($9.82^{\circ}C$) > valley ($8.44^{\circ}C$), the relative humidity valley (59.01 %) > ridge (58.64 %), the solar radiation ridge ($34.40W/m^2$) > valley($14.69W/m^2$), the wind speed ridge (0.63m/s) > valley(0.37m/s), and the negative ion valley($636.81ea/cm^3$) > ridge($580.04ea/cm^3$). In the valley, the correlation with altitude was verified for the temperature, relative humidity, solar radiation, and negative ion generation in the valley. The relative humidity, solar radiation, and negative ion indicated a positive correlation while the temperature had a negative correlation. In the ridge, the correlation with altitude was verified for the temperature, relative humidity, wind speed, solar radiation, and negative ion generation. The relative humidity, solar radiation, and negative ion generation indicated a positive correlation while the temperature and wind speed had a negative correlation. The regression analysis showed the prediction equation of y=-0.006x+9.663 (x=altitude, y=temperature) in the valley and y=-0.009x+11.595 (x=altitude, y=temperature) in the ridge for the temperature, y=0.027x+53.561 (x=altitude, y=relative humidity) in the valley and y=0.008x+56.646 (x=altitude, y=relative humidity) in the ridges for the relative humidity, and y=0.027x+53.561 (x=altitude, y=negative Ion generation) in the valley and y= 0.008x+56.646 (x=altitude, y=negative Ion generation) in the ridge for the negative ion generation.

• Journal of the Korea Concrete Institute
• /
• v.14 no.1
• /
• pp.126-135
• /
• 2002

Plate bonding technique has been widely used in strengthening of existing concrete structures, although it has often a serious problem of premature falure such as interface separation and rip-off. However, this premature failure problem has not been well explored yet especially in view of local failure mechanism around the interface of plate ends. The purpose of the present study is, therefore, to identify the local failure of strengthened plates and to derive a separation criterion at the interface of plates. To this end, a comprehensive experimental program has been set up. The double lap pull-out tests considering pure shear force and half beam tests considering combined flexure-shear force were performed. The main experimental parameters include plate thickness, adhesive thickness, and plate end arrangement. The strains along the longitudinal direction of steel plates have been measured and the shear stress were calculated from those measures strains. The effects of plate thickness, bonded length, and plate end treatment have been also clarified from the present test results. Nonlinear finite element analysis has been performed and compared with test results. The Interface properties are also modeled to present the separation failure behavior of strengthened members. The cracking patterns as well as maximum failure loads agree well with test data. The relation between maximum shear and normal stresses at the interface has been derived to propose a separation failure criterion of strengthened members. The present study allows more realistic analysis and design of externally strengthened flexural member with steel plates.

• Management & Information Systems Review
• /
• v.38 no.1
• /
• pp.201-223
• /
• 2019

The purpose of this study is to verify empirically the causal relationship between service quality, ease of use, customer satisfaction, and repurchase intention of mobile shopping mall. And this study is to investigate the ease of use and customer satisfaction mediating effect of between service quality and repurchase intention. Therefore, 323 university students in Jeonnam area were surveyed and the structural equation model was derived based on previous research. Service quality of mobile shopping mall make a significant effect on using easiness, purchasing satisfaction and repurchase intention. However, among service quality of mobile shopping mall, service scape like mobile interface and site design made a positive effect on purchasing satisfaction, but did not any effect on repurchase intention. In other words, service quality factors that make positive effects on customer's pleasant using and repurchase intention make a positive effect on repurchase intention when providing and using the service customer wants faithfully rather than external part of the site and mutually influencing attitude or behavior well. The implications suggested by this study are as follows. First, service quality of mobile shopping mall makes a significant effect on repurchase intention, so it's necessary to improve CS service system so as to treat customers' inquiries or inconveniences actively during mobile shopping and return and refund of defective products quickly and conveniently. And, in addition to the finally used factors in analysis process, benefits using customers' grade by number of purchases, such as various events, coupons, reserve, etc. and active contents marketing strategies providing more various pleasures and values of shopping are necessary. Second, satisfaction of mobile shopping mall makes a positive effect on repurchase intention, so visiting of site and repurchasing of product are continuously done as customers' satisfaction on shopping mall is increasing. Therefore, shopping mall site requires differentiation of contents, exact plan and practice of service, marketing, etc. so that customers can feel more satisfaction. This study is significant as it systematically analyzed concepts of components that service quality of mobile shopping mall makes an effect on using easiness, purchasing satisfaction, and repurchase intention, verified the relations, systematized it by theoretical structure, and widened the understanding of effects making an effect on repurchase intention.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.12
• /
• pp.552-560
• /
• 2018

Since 1960's, the large conglomerates of South Korea have grown due to the corporate-centered, fast-paced growth drive, while the small and medium-sized businesses supported the country's economy as the subordinate structure of these conglomerates. Due to the globalization of the business environments, the focus of competition shifted from competitions between individual companies to one between networks of companies. Therefore, more emphasis is now put on the capabilities of the cooperation networks between companies rather than the capabilities of individual companies. Therefore, in this study, the author examined the influence of the win-win growth strategy elements through cooperation with small and medium-sized businesses upon corporate performance. This study was conducted with the workers of small and medium-sized businesses that have previous cooperation experiences with South Korean conglomerates over the period from March 2 to May 17, 2018. For this, a total of 515 questionnaires were retrieves to obtain the data for analysis. The analysis was conducted using SPSS 22.0 and AMOS 18.0. The analytical processes that were taken included exploratory factor analysis, confirmatory factor analysis, confidence analysis, correlation analysis, and structural equation analysis model. The results of the analysis showed that, first of all, the win-win growth strategy factors that affected the strategic performance, which is a part of cooperate performance were, respectively, harmonization with the goals, production technical support, and quality system. Second, the win-win growth strategy factors that affected the financial performance, which is a part of corporate performance, turned out to be harmonization with the goals, quality system, and incentive. With the results of this study, it was shown that the elements such as harmonization with the goals, production technical support, quality systems, and incentives were key infrastructural factors that affected the corporate performance directly. On the other hand, its implication is that informative or knowledge-related factors, such as joint knowledge creation, do not have their own added values, while they are not too much likely to affect corporate performances for the moment.

• Economic and Environmental Geology
• /
• v.54 no.6
• /
• pp.709-716
• /
• 2021

In this study, an adsorbent prepared by natural drying of iron hydroxide-based sludge collected from settling basin at a mine drainage treatment facility located in Gangneung, Gangwon-do was used to remove fluoride in an artificial fluoride solution and mine drainage, and the adsorption characteristics of the adsorbent were investigated. As a result of analyzing the chemical composition, mineralogical properties, and specific surface area of the adsorbent used in the experiment, iron oxide (Fe₂O₃) occupies 79.2 wt.% as the main constituent, and a peak related to calcite (CaCO₃) in the crystal structure analysis was analyzed. It was also identified that an irregular surface and a specific surface area of 216.78 m²·g^-1. In the indoor batch-type experiment, the effect of changes in reaction time, pH, initial fluoride concentration and temperature on the change in adsorption amount was analyzed. The adsorption of fluoride showed an adsorption amount of 3.85 mg·g^-1 16 hours after the start of the reaction, and the increase rate of the adsorption amount gradually decreased. Also, as the pH increased, the amount of fluoride adsorption decreased, and in particular, the amount of fluoride adsorption decreased rapidly around pH 5.5, the point of zero charge at which the surface charge of the adsorbent changes. Meanwhile, the results of the isotherm adsorption experiment were applied to the Langmuir and Freundlich isotherm adsorption models to infer the fluoride adsorption mechanism of the used adsorbent. To understand the thermodynamic properties of the adsorbent using the Van't Hoff equation, thermodynamic constants 𝚫H° and 𝚫G° were calculated using the adsorption amount information obtained by increasing the temperature from 25℃ to 65℃ to determine the adsorption characteristics of the adsorbent. Finally, the adsorbent was applied to the mine drainage having a fluoride concentration of about 12.8 mg·L^-1, and the fluoride removal rate was about 50%.

• Journal of the Korean Geotechnical Society
• /
• v.38 no.7
• /
• pp.49-62
• /
• 2022

The hollow modular concrete block reinforced foundation method is one of the ground reinforcement foundation methods that uses hexagonal honeycomb-shaped concrete blocks with mixed crushed rock to reinforce soft grounds. It then forms an artificial layered ground that increases bearing capacity and reduces settlement. The hollow modular honeycomb-shaped concrete block is a geometrically economical, stable structure that distributes forces in a balanced way. However, the behavioral characteristics of hollow modular concrete block reinforced foundations are not yet fully understood. In this study, a bearing capacity test is performed to analyze the reinforcement effectiveness of the hollow modular concrete block through the laboratory model tests. From the load-settlement curve, punching shear failure occurs under the unfilled sand condition (A-1-N). However, the filled sand condition (A-1-F) shows a linear curve without yielding, confirming the reinforcement effect is three times higher than that of unreinforced ground. The bearing capacity equation is proposed for the parts that have contact pressure under concrete, vertical stress of hollow blocks, and the inner skin friction force from horizontal stress by confining effect based on the schematic diagram of confining effect inside a hollow modular concrete block. As a result of calculating the bearing capacity, the percentage of load distribution for contact force on the area of concrete is about 65%, vertical force on the area of hollow is 16.5% and inner skin friction force of area of the inner wall is about 18.5%. When the surcharge load is applied to the concrete part, the vertical stress occurs on the area of the hollow part by confining effect first. Then, in the filled sand in the hollow where the horizontal direction is constrained, the inner skin friction force occurs by the horizontal stress on the inner wall of the hollow modular concrete block. The inner skin friction force suppresses the punching of the concrete part and reduces contact pressure.

• Clean Technology
• /
• v.28 no.3
• /
• pp.218-226
• /
• 2022

As a result of the recent social transformation towards a hydrogen economy and carbon-neutrality, the demands for hydrogen energy have been increasing rapidly worldwide. As such, eco-friendly hydrogen production technologies that do not produce carbon dioxide (CO₂) emissions are being focused on. Among them, ammonia (NH₃) is an economical hydrogen carrier that can easily produce hydrogen (H₂). In this study, Ru/Al₂O₃ catalyst coated onmetallic monolith for hydrogen production from ammonia was prepared by a dip-coating method using a catalyst slurry mixture composed of Ru/Al₂O₃ catalyst, inorganic binder (alumina sol) and organic binder (methyl cellulose). At the optimized 1:1:0.1 weight ratio of catalyst/inorganic binder/organic binder, the amount of catalyst coated on the metallic monolith after one cycle coating was about 61.6 g L^-1. The uniform thickness (about 42 ㎛) and crystal structure of the catalyst coated on the metallic monolith surface were confirmed through scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Also, a numerical optimization regression equation for NH3 conversion according to the independent variables of reaction temperature (400-600 ℃) and gas hourly space velocity (1,000-5,000 h^-1) was calculated by response surface methodology (RSM). This model indicated a determination coefficient (R²) of 0.991 and had statistically significant predictors. This regression model could contribute to the commercial process design of hydrogen production by ammonia decomposition.

• Journal of the Korean Society of Tobacco Science
• /
• v.24 no.1
• /
• pp.67-73
• /
• 2002

In light of addressing consumer health concern, coping with anti-tobacco movement, and promoting new product, tobacco industry is actively pursuing to make a new generation of cigarettes with low tar and nicotine deliveries, and less harmful substances. Low tar and low nicotine cigarettes increases their market shares dramatically world wide, especially in KT&G, multinational tobacco companies, EU countries, even in China regulated by CNTC to set up yearly target to lower tar and nicotine deliveries. On the other hand, to design a new cigarette with reduced harmful substances begins to gain speed. The "modified Hoffmann list" publishes thirty plus substances in tobacco leaf and main smoke stream, which is the prime suspect causing health problems. Various ways and means are developed to reduce such components including new tobacco breeds, new curing method, tobacco leaf treatment before processing, selected filtration system, innovated casing system to reduce free radicals, as well as some non conventional cigarette products. In TSRC held this year, the main topic is related to reduce tobacco specific nitrosamines in tobacco leaf. The new generation of cigarette is in the horizon. It still needs a lot help to produce commercial products with satisfied taste and aroma characters. The flavor industry is not regulated by many governments demanding which ingredients might or might not be for tobacco use. However, most of the cigarette companies self impose a list of ingredients to guide flavor suppliers to design flavors. Unfortunately, the number of ingredients in those lists is getting shorter every year. It is understandable that the health is not the only reason. Some cigarette companies are playing safe to protect the company from potential lawsuit, while others are just copying from their competitors. Moreover, it is obvious that it needs more assistance from casings and flavors to design new generation of cigarettes with missing certain flavor components in tobacco leaf and main smoke stream. These flavor components are either non-existed or at lower level at new form of cured tobacco leaf or filtered in the main smoke stream along with reduced harmful substances. The use of carbon filters and other selected filtration system poses another tough task for flavor system design. Specific flavor components are missing from the smoke analysis data, which brings a notion of "carbon taste" and "dryness" of mouth feel. It is ever more demanded by cigarette industry to flavor suppliers to produce flavors as body enhancer, tobacco notes, salivating agents, harshness reducer, and various of aromatic notes provided they are safe to use. Another trend is that water based flavor or flavor with reduced ethanol as solvent is gaining popularity. It is preferred by some cigarette companies that the flavor is compounded with all natural ingredients or all ingredients should he GMO free. The new generation of cigarettes demands many ways of new thinking process. It is also vital for tobacco industry. It reflects the real needs for the consumers that the cigarette product should be safe to use as well as bearing the taste and aroma characters smokers always enjoyed. An effective tobacco flavor system is definitely a part of the equation. The global trend of tobacco industry is like trends of any other industries lead by consumer needs, benefited with new technology availability, affected by the global economy, and subjected for various rules and regulations. Anti-tobacco organizations and media exceptionally scrutinize cigarette, as a legal commercial product. Cigarette is probably the most studied commercial product for its composition, structure, deliveries, effects, as well as its new developmental trend. Therefore, any new trend of cigarette development would be within these boundaries. This paper is trying to point out what it would be like for tobacco industry in the next few yews and what concerns the tobacco industry. It focuses mostly on the efforts to produce safer cigarettes. It is such a vital task for the tobacco industry and its affiliate industries such as cigarette papers, filters, flavors, and other materials. The facts and knowledge presented in this paper might be well known for the public. Some of the comments and predictions are very much personal opinion for a further discussion.

• Geophysics and Geophysical Exploration
• /
• v.26 no.1
• /
• pp.18-30
• /
• 2023

Submarine mud volcanos are topographic features that resemble volcanoes, and are formed due to eruptions of fluidized or gasified sediment material. They have gained attention as a source of subsurface heat, sediment, or hydrocarbons supplied to the surface. In the continental slope of the Canadian Beaufort Sea, mud volcano exists at various water depths. The MV420, is an active mud volcano erupting at a water depth of 420 meters, and it has been the subject of extensive study. The Korea Polar Research Institute(KOPRI) collected high-resolution seismic data and heat flow data around the caldera of the mud volcano. By analyzing the multi-channel seismic data, we confirmed the reverse-polarity reflector assumed by a gas hydrate-related bottom simulating reflector(BSR). To further elucidate the relationship between the BSR and gas hydrates, as well as the thermal structure of the mud volcano, a numerical geothermal model was developed based on the steady-state heat equation. Using this model, we estimated the base of the gas hydrate stability zone and found that the BSR depth estimated by multi-channel seismic data and the bottom of the gas hydrate stability zone were in good agreement., This suggests the presence of gas hydrates, and it was determined that the depth of the gas hydrate was likely up to 50 m, depending on the distance from the mud conduit. Thus, this depth estimate slightly differs from previous studies.

• Korean Journal of School Psychology
• /
• v.16 no.3
• /
• pp.433-451
• /
• 2019

This study aimed to develop and validate the Classroom Problem Behavior Scale - Elementary School Version (CPBS-E) measure which is unique to classroom problem behavior exhibited by Korean elementary school students. The focus was on developing a universal screening instrument designed to identify and provide intervention to students who are at-risk for severe social-emotional and behavioral problems. Items were initially drawn from the literature, interviews with elementary school teachers, common office discipline referral measures used in U.S. elementary schools, penalty point systems used in Korean schools, 'Green Mileage', and the Inventory of Emotional and Behavioral Traits. The content validity of the initially developed items was assessed by six classroom and subject teachers, which resulted in the development of a preliminary scale consisting of 63 two-dimensional items (i.e., Within Classroom Problem Behavior and Outside of Classroom Problem Behavior), each of which consisted of 3 to 4 factors. The Within Classroom Problem Behavior dimension consisted of 4 subscales (not being prepared for class, class disruption, aggression, and withdrawn) and the Outside of Classroom Problem Behavior dimension consisted of 3 subscales (rule-violation, aggression, and withdrawn). The CPBS-E was pilot tested on a sample of 154 elementary school students, which resulted in reducing the scale to 23 items. Following the scale revision, the CPBS-E was validated on a sample population of 209 elementary school students. The validation results indicated that the two-dimensional CPBS-E scale of classroom problem behavior was a reliable and valid measure. The test-retest reliability was stable at above .80 in most of the subscales. The CPBS-E measure demonstrated high internal consistency of .76-.94. In examining the criterion validity, the scale's correlation with the Teacher Observation of Classroom Adaptation-Checklist (TOCA-C) was high and the aggression and withdrawn subscales of the CPBS-E demonstrated high correlations with externalization and internalization, respectively, of the Child Behavior Checklist - Teacher Report Form CBCL-TRF). In addition, the factor structure of the CPBS-E scale was examined using the structural equation model and found to be acceptable. The results are discussed in relation to implications, contributions to the field, and limitations.