• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.161-166
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• 2014

In this study, effects of pyrite ($FeS_2$) particle sizes on the electrochemical characteristics of thermal batteries are investigated using unit cells made of pulverized pyrite by ball-milling. At $450^{\circ}C$ unit cell discharge test, the electrochemical capacity of $1.46{\mu}m$ pyrite-cell largely increases compared to $98.4{\mu}m$ pyrite-cell, and their internal resistances also decrease. These results are attributed to the increase in the active reaction area of pyrite by ball milling. However, at $500^{\circ}C$ unit cell discharge test, a $1.46{\mu}m$ pyrite cell shows lower internal resistance than that of $98.4{\mu}m$ pyrite cell only at Z-phase region ($FeS_2{\rightarrow}Li_3Fe_2S_4$). After that, a $1.46{\mu}m$ pyrite cell shows a decrease in the cell voltage and an rapid increase of the internal resistance in J-phase region ($Li_3Fe_2S_4{\rightarrow}LiFe_2S_4$) is observed compared to those of $98.4{\mu}m$ pyrite cell. It can be concluded that at the higher temperature, the thermally unstable pulverized pyrite is decomposed thermally as well as self discharged, simultaneously, which causes the higher resistance and lower capacity at $500^{\circ}C$ in J-phase than that of $98.4{\mu}m$ pyrite cell.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.41-49
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• 2009

Cement concrete pavement has become more common in Korean highway systems. However, as its service period increases, there are some technical problems occurs and no clear solution is available primarily due to the lack of active researches. This research, hence, aims to develop a new mix proportion that may provide better strength and durability with extended service life. Based on a variety of literature reviews, the experimental variables were determined as unit cement content, S/a ratio and W/C ratio. From the experimental works, it is recommended to increase the unit cement content up to 375kg/$m^3$, 400kg/$m^3$ and 425kg/$m^3$. The target slump and air content were set 40mm and 5%, respectively. The maximum size of coarse aggregate was decided to be 25mm because of the easiness of supply in the field. The reduction of W/C ratio was necessarily required and decreased to 0.4 which was proven not to cause any mixing problem with the increased unit cement contents along with polycarbon-based high range water reducing agent. In addition, it was known that the S/a ratio could be reduced to 0.34. The lowered S/a might be possible because of the increased cement paste and hence increased cohesiveness and workability.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.393-405
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• 2006

The purpose of this study was to analyze the effects of Semantic Network Program (SNP) instruction on learning achievement and motivation in high school biology classes. For this study, a SNP was designed by applying the recommendations in regard to student attention and satisfaction factors in Keller's ARCS theory. SNP instruction was conducted with an experimental group and a control group, each consisting of 62 high school biology class student. A pretest-posttest control group design was employed. The pre-test was used to analyze the learning achievement test, learning motivation test, and semantic forming test. For 4 weeks the experiment group was instructed using the developed SNP which centered on Keller's attention and satisfaction factors, and the control group was instructed via teacher-centered lectures based on the textbook. It was found that SNP instruction efficiently increased students' biology learning achievement (p<.001). It was also discovered that SNP instruction was effective in increasing Keller's motivation strategies on attention and satisfaction factors (p<.001). In addition, SNP instruction positively affected students' semantic formation (p<.001) and learning content retention (p>.05) in the heredity unit by aiding students in the area of active multimedia learning. An in depth interview with students in the class using SNP instruction showed that material learned via this method in biology had longer retention of problem-solving methods. Consequently, SNP instruction according to motivation strategies may high school biology teachers with meaningful teaching-learning methods strategies for the unit on heredity.

• Journal of Nutrition and Health
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• v.23 no.2
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• pp.135-147
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• 1990

This study was devised to observe the cytotoxic activities of garlic extracts against various cancer cells, that is, murine leukemic lymphocyte(L1210 and P388) and human rectal(HRT-18) and colon cancer cells(HCT-48 and HT-29) in vitro, and murine ascitic tumor cell(S-180) in vivo. Each cell-line except S-180 was cultured in medium containing serial concentration of the garlic extract in vitro. Inhibitory effect n the growth rate of the cancer cells was stronger in extracts of petroleum ether than that of ethanol. A lipid soluble compound in the extracts of garlic was cytocidal to murine leukemic cells, human rectal and colon cancer cells in vitro. The growth rates of the cancer cells in medium containing garlic extracts were inhibited gradually to a significant degree in proportion to the increase of the extract concentration. The cytotoxic activity of garlic active fraction from TLC was about 2.3 times more potent than that of crude garlic extract, one unit of cytotoxic activity against L1210 cells being equivalent to 4.2$\mu\textrm{g}$ and 1.8$\mu\textrm{g}$ from the crude garlic and active fraction, respectively. The Rf value of the active fraction on silica-gel TLC was 0.18 in condition that petroleum ether/ethyl ether/acetic acid mixture(90:10:1, v/v/v) was used as a developing solvent. The survival times of mice inoculated with S-180 cells were extended about 1.5 to 2 times in the groups treated with garlic extract(through i.p. and oral administration) compared with their control group(no garlic extract treatment). Observations were carried out on S-180. Ethanol extracts of garlic injured markedly tumor cells within 3 hours after injection.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.4
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• pp.562-567
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• 2009

As a key mechanism of the human emotion interaction, Facial Expression is a powerful tools in HRI(Human Robot Interface) such as Human Computer Interface. By using a facial expression, we can bring out various reaction correspond to emotional state of user in HCI(Human Computer Interaction). Also it can infer that suitable services to supply user from service agents such as intelligent robot. In this article, We addresses the issue of expressive face modeling using an advanced active appearance model for facial emotion recognition. We consider the six universal emotional categories that are defined by Ekman. In human face, emotions are most widely represented with eyes and mouth expression. If we want to recognize the human's emotion from this facial image, we need to extract feature points such as Action Unit(AU) of Ekman. Active Appearance Model (AAM) is one of the commonly used methods for facial feature extraction and it can be applied to construct AU. Regarding the traditional AAM depends on the setting of the initial parameters of the model and this paper introduces a facial emotion recognizing method based on which is combined Advanced AAM with Bayesian Network. Firstly, we obtain the reconstructive parameters of the new gray-scale image by sample-based learning and use them to reconstruct the shape and texture of the new image and calculate the initial parameters of the AAM by the reconstructed facial model. Then reduce the distance error between the model and the target contour by adjusting the parameters of the model. Finally get the model which is matched with the facial feature outline after several iterations and use them to recognize the facial emotion by using Bayesian Network.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.12
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• pp.1380-1393
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• 2010

This paper presents a design, fabrication and the test results of planar active electronically scanned array(AESA) radar prototype for airborne fighter applications using transmit/receive(T/R) module hybrid technology. LIG Nex1 developed a AESA radar prototype to obtain key technologies for airborne fighter's radar. The AESA radar prototype consists of a radiating array, T/R modules, a RF manifold, distributed power supplies, beam controllers, compact receivers with ADC(Analog-to-Digital Converter), a liquid-cooling unit, and an appropriate structure. The AESA antenna has a 590 mm-diameter, active-element area capable of containing 536 T/R modules. Each module is located to provide a triangle grid with $14.7\;mm{\times}19.5\;mm$ spacing among T/R modules. The array dissipates 1,554 watts, with a DC input of 2,310 watts when operated at the maximum transmit duty factor. The AESA radar prototype was tested on near-field chamber and the results become equal in expected beam pattern, providing the accurate and flexible control of antenna beam steering and beam shaping.

• Proceedings of the Ginseng society Conference
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• 1988.08a
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• pp.147-150
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• 1988

Polysaccharides which show reticuloendothelial system potentiating activity in carbon clearance tests have been examined in water extracts of Panx species. From the dried roots of P. notoginseng, an active polysaccharide called sanchinan-A was isolated. The molecular weight of sanchinan-A was estimated to be 1,500,000D and the structure was determined to be $\beta$-D-(1-3-galactan), possessing branch points at positions 0-6 at which (mainly-$\alpha$-L-arabinofuranosyl and partly $\beta$-D-galactopyranosyl)-(1-6)-$\beta$-D-galacto-pyranosyl-(1-3)-$\beta$-D-galactopyranosyl side chains are attached on average, to two of three galactosyl units. From dried rhizomes of P. japonicus, several active polysaccharides were also isolated, and these structuers were also determined. From the dried roots of P. ginseng, several polysaccharides which showed strong activity were isolated. The structures of these compounds are currently under investigation. The polysaccharide fraction (non-dialyzed fraction) of the water extract of red ginseng (steam-dried roots) did not exhibit activity, while the dialyzed fraction potentiated RES. Activity disappeared, however, during the process of separation due to the presence of a substance in the fraction which stabilizes an active substance.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.957-964
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• 2010

The deactivated catalyzed diesel particulate filter-trap (DPF) was remanufactured by ultrasonic wave treatment with various prepared solutions, followed by active component re-impregnation, and the emission control performance and surface properties of remanufactured DPF were studied at various remanufacturing conditions. The proper ultrasonic wave cleaning time at various prepared solutions and optimal re-impregnation amounts of active component for the best emission control performance of DPF were investigated and its performance tests were also carried out with various temperatures for the conversions of CO, THC (total hydrocarbon) and PM (particulate matter) by catalytic reaction test unit using bypass gas from the diesel engine dynamo system. It was found that the emission control performance of DPF remanufactured with the high-temperature air washing, ultrasonic wave cleaning at acid/base solutions and active component re-impregnation method was recovered to 95% level of its activity compared to that of the fresh DPF, which was caused by removing the deactivating materials from the surface of the DPF, through the analyses of performance test and their surface characterization by Optical microscope, EDX, ICP, TGA, and porosimeter.

• International Journal of Control, Automation, and Systems
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• v.5 no.4
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• pp.429-435
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• 2007

A number of different alternative actuation methods have been under active development for some specific applications where the traditional electromechanical actuators are difficult to apply. Recently, many of these substitutes are trying to employ new smart materials like electroactive polymers. However most of the polymeric materials are flexible and vulnerable so that they normally can not sustain external forces. Although the materials have shown a good potential to be used for alternative actuation mechanisms, no tangible industrial application is yet presented because of the reason. A conceptual design for a rectilinear motion actuator using dielectric elastomer is presented in this article. The introduced design concept might enable to produce fairly controllable rectilinear motions for various applications and the presented prototype actuator system is fully packaged in a small unit and controlled by a standard communication interface.

• Journal of the Korean housing association
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• v.24 no.2
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• pp.69-76
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• 2013

With people leaving the countryside to the cities as a result of industrialization and urbanization and drastic reduction of school children due to low birthrate, nationwide, total 3,438 schools have been shut down following the closed schools policy. Consequently, local governments have been active in selling, utilizing, and leasing the closed schools but there are still 466 closed schools that need to be addressed quickly. In addition to this phenomenon, aging population has become an important issue, and demand for elderly welfare facilities population is also increasing as a result. However, the supply of welfare services remains inadequate. This study was conducted in an attempt to solve both local and social problems at the same time, caused by the closing of schools and an aging population, through the use of closed schools as elderly welfare facilities, and suggests plans for per-unit space according to its type, and prototype, through research analysis of practical use, based on case studies. With the conclusions of both advantages and disadvantages, drawn from its type, we are hoping to be able to use this study by adapting its type, or mixing, according to one's needs.