• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5789-5794
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• 2015

Recently, thin and light-weight production technologies are needed in IT industry in accordance with increase of the smart phones and mobile PC products. In order to make light and high rigidity products, engineering plastic and aluminum materials are frequently used in products appearance and frame hat support structure. Especially aluminum extrusion and CNC Brick processes are widely used for high strength and high rigidity technology. But extrusion method has constraints to apply exterior design and CNC Brick process has relatively high production cost and low speed of manufacturing. In this research, a new process method is introduced in order to reduce material cost and to improve manufacturing speed dramatically. Plate forging process means basically that thickening of local wall area thickness after deform exterior shape by deep drawing and bending process. Therefore, it is possible to minimize the waste of material and the manufacturing time. In this study the process of plate forging is designed using finite element program AFDEX-2D and the thickness and the width of initial deformed blank. And it is verified as a sample which is a part of laptop developed through the proposed plate forging method.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.4
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• pp.237-245
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• 2014

Amur silver grass (Miscanthus sacchariflorus) and reed canary grass (Phalaris arundinacea) were selected for RDX removal experiments in hydroponic culture conditions based on vegetation survey at three shooting ranges in northern Kyunggi province. Seedling of two plants were grown in 1/4 strength Hoagland solution in quadruplicates containing 10, 20, 30, 40 mg/L RDX for 15 days along with control and blank treatments. During the 15 days of incubation, pH and RDX concentration in medium were routinely analyzed and RDX contents in the shoot and the root were determined after solvent extraction at the end of the experiments. Both plant species showed no symptoms of RDX phyto-toxicity. The pseudo first order RDX-removal constants for amur silver grass and reed canary grass were in the range of $0.0143{\sim}0.0484day^{-1}$ and $0.0971{\sim}0.1853^{-1}$, respectively. Plant biomass normalized RDX removal rates, which decreased with the increase of initial RDX concentration, were in the range of $0.27{\sim}1.01mL{\cdot}g^{-1}day^{-1}$ and $0.87{\sim}1.66mL{\cdot}g^{-1}day^{-1}$ for amur silver grass and reed canary grass, respectively. After 15 days of treatment, RDX removal from the medium decreased from 49.0% to 23.7% with increase in the initial RDX concentration in amur silver grass and 7.3% of the initial RDX remained in the plant. In reed canary grass planted medium, less than 16.8% and 5% of the initial RDX remained in the medium and in the plant, respectively. Large quantities of unidentified polar compound, which was not detected in amur silver grass, accumulated in the root and shoot of reed silver grass.

• Korean Journal of Cognitive Science
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• v.24 no.1
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• pp.49-69
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• 2013

While we interact with other people or objects, the brain continuously updates our own body schema to recognize the agent of observed actions. The Extrastriate Body Area (EBA) provides an initial interface for the sense of agency by integrating visual inputs of body parts with internal signals related to self-generated body movements. Less is known, however, about how the functional use of tools contributes to such processes. Here, we investigated whether tool-specific affordance would differentially affect the neural responses in the EBA depending on the agency of imaginary actions. In each trial we presented a picture of an object in a rectangular frame. Objects were either the tools typically brought towards the body (body tools; e.g., telescope, earphones) or away from the body (world tools; e.g., pen, dice; Rueschemeyer, Pfeiffer, & Bekkering, 2010). Depending on the color of the frame, participants imagined either themselves or the other person using the tool (self vs. other conditions). These four types of trials were randomly intermixed with blank trials. As results, independently localized right EBA regions of interest showed greater activation when participants imagined themselves using body tools than using world tools whereas no such differential activations were found when they imagined the other person using the tools. The postscan test revealed no significant difference in vividness of imagery between the self and other conditions. Our results suggest that the EBA incorporates functional affordance of tools into the body schema in order to enhance the sense of agency and to guide our own actions.

• Journal of the Korean earth science society
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• v.30 no.1
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• pp.141-151
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• 2009

Inquiry has been emphasized in science classrooms, but the problems shown in the inquiry are somewhat different with ones that students usually meet and experience in everyday life. The purpose of this study is to investigate how attitudes toward the task and thinking skills affect students' problem solving process, especially, the way of creating a problem space and elaborating problem solving strategies when they have little schema. The difference in students' problem solving strategies of Lego Robotics class, one of the summer programs for $4^{th}-6^{th}$ grade gifted students, which is new to them, was investigated. The results are as follows: (1) The difference in attitudes toward the task, or selection and identification of the missions, and the perception of operators, affected creating a different problem space. (2) Different level of thinking skills, or analytical and flexible thinking, efficient elaborative skill, and application of schema affected a different level of elaboration of the problem space and resulted in asuccess rate of problem solving. (3) Different initial problem space resulted in different problem solving strategies. But without thinking skills, students could not elaborate problem solving strategies efficiently. Several instructional recommendations to promote scientific inquiry were suggested based on the results.

• Journal of Navigation and Port Research
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• v.34 no.5
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• pp.367-373
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• 2010

When the numerical analysis is carried out, it is necessary to set proper elements as a feature of analysis domains for more accurate simulations. In this study, Distinct Element Method(DEM) is applied, only considering repulsive force and tensile force except for frictional force and resisting force of particle. When the filled particles with initial Quad-tree type is relocated by DEM, a blank space existing among the particles can be minimized because the shape of particle is circular. Finally, it is the effective feature that the centroidal disposion of the particles is similar to an equilateral triangle. Triangular mesh are formed by using the Delaunay triangular technique on these relocated particles, the quality of triangular mesh is more improved by carrying out Laplace interpolations. The compared result of Aspect Ratio before and after the Laplace interpolation is shown that although the quality of triangular mesh made by DEM is good, the later triangular mesh are higher quality than the formers. In this study, although the developed technique takes a longer calculational time than the previous technique to generate triangular mesh, it is considered that the applicable possibility is very high in the generation of finite element mesh about wave analysis and various numerical simulation to need a complex or reappearance of exact topography.

• Applied Biological Chemistry
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• v.8
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• pp.51-59
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• 1967

A split plot was laid out in 1965 for perennial application of straw by 500kg per 10 are, as main plot, and of chemical fertilizer in conventional way, as sub-plots. The sub-plot included the following 5 fertilizer treatments as (1) non-fertilized, (2) nitrogen-free, (3) phosphate-free (4) potassium-free, (5) completely fertilizer applied plots. Trends in the growth and yield of rice was observed at present experimental site in the first year, 1965, and second year, 1966, as follows: 1. Each treatmental plot showed nearly identical trends between the first and second year, in term of growth, yield and yield components. 2. Straw application deterred the initial growth at non-fertilized and nitrogen-free plots. But straw application raised the effective stem ratio and enlarged the values in yield components, finally to be resulted in the second year with significant difference. 3. Both phosphate and potassium did not much affected to plants for longer stem and larger number of tillers. 4. Effect of nitrogen, phosphate and potassium was recorded as investigated by previous research works. Phospate deficiency decreased maturing rate to a great extent. 5. Numerical index was calculated for the comparison of plots in yield, where the non-straw, completely fertilizer applied plot stands for 100. The indexes of the first and second year were as follows : at non-straw plot(indexes in the blank are from the first year trial); non-fertilized : 80.2(80.9), nitrogen-free: 83.6(89.4), phosphate-free : 89.4(93.1) and potassium-free plot: 93.5(102.4) at non-straw plot. On the other hand, indexes at straw applied plots were non-fertilized : 84.0(86.6), nitrogen-free 82.6(93.9), phosphate-free : 91.7(96.3), potassium-free: 103.2(102.0) and complete plot: 98.7(109.8).

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.33-42
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• 2000

Adsorption onto the surfaces of solid particles is a well known phenomenon that causes the retardation effect of heavy metals in soils. For adequate remediation of soil and groundwater contamination, it is important to investigate the mobility of heavy metals that largely depends on pH conditions in the soil water since adsorption of heavy metals is pH-dependent. In this study, we investigated the transport of Zn ion under various pH conditions in a sandy soil by conducting batch and column tests. The batch test was performed using the standard procedure of equilibrating fine fractions collected from the soil with eleven different initial $ZnCl_2$ concentrations, and analysis of Zn ion in the equilibrated solutions using ICP-AES. The column test consisted of monitoring the concentrations of soil solutions exiting the soil column with time known as a breakthrough curve (BTC). We injected respectively $ZnCl_2$ and KCl solutions with the concentration of 10 g/L as a tracer in a square pulse type under three different pH conditions (7.7, 5.8, 4.1) and monitored the flux concentration at the exit boundary using an EC meter and ICP-AES. The resident concentration was also monitored at the 10cm-depth by Time Domain Reflectometry (TDR). The results of batch test showed that ion exchange process between Zn and other cations (Ca, Mg) was predominant. The retardation coefficients obtained from adsorption isotherms (Linear, Freundlich, Langmuir) resulted in the various values ranging from 1.2 to 614.1. No retardation effect but ion exchange was found for the BTCs under all pH conditions. This can be explained by the absence of other cations to desorb Zn ion from soil exchange sites under the conditions of ETC experiment imposing blank water as leachate in steady-state flow. As pH decreased, the peak concentration of Zn increased due to the competition of Zn with hydrogen ions ($H^+$) and the concentrations of other cations decreased. The peak concentration of Zn was increased by 12.7 times as pH decreased from 7.7 to 4.1.