• Korean Journal of Materials Research
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• v.11 no.8
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• pp.661-665
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• 2001

The mechanical alloying (MA) effect in $\sigma$-VFe intermetallic compound was studied by neutron and X-ray diffraction. The structure of MA $\sigma$-VFe powders were characterized by the X- ray diffraction with Cu- $K\alpha$ radiation and neutron diffraction with monochromatic neutrons of $1.835\AA$ using a high resolution powder diffractometer (HRPD). Mechanical alloying of $\sigma$-VFe compound gives rise to a dramatic structural change. After 60 hours of MA, the Fe-Fe distribution of the $\sigma$- phase VFe tetragonal structure with 30 atoms in a unit cell is found to change into that of the $\sigma$-(V,Fe) solid solution with bcc structure, which is a stable phase at elevated temperature above $1200^{\circ}C$. A comparison of X-ray diffraction data for the $\alpha$-phase has been also made with the corresponding neutron diffraction data. The (101) and (111) diffraction peaks of the $\sigma$-phase was clearly observed only in neutron diffraction pattern, which is believed to be a characteristic feature due to the chemical atomic ordering of $\sigma$- VFe phase.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.2
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• pp.69-73
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• 2010

The microstructural change of the $Sm_{0.5}Sr_{0.5}CoO_3$ (SSC) electrode for a cathode material of solid oxdie fuel cells (SOFCs) deposited by the electrostatic spray deposition (ESD) technique was characterized. Samarium chloride hexahydrate $(SmCl_3{\cdot}6H_2O)$, strontium chloride hexahydrate $(SrCl_2{\cdot}gH_2O)$, cobalt nitrate hexahydrate $(Co(No_3)_2{\cdot}6H_2O)$ as starting materials and methyl alcohol as solvent were used to make precursor solution. The suitable porous SSC films for a cathode of SOFCs were deposited on Si substrate and it is observed that the microstructure was strongly dependent on processing parameters such as deposition time, substrate temperature, and applied voltage. Scanning Electron Microscope (SEM) and X-ray Diffractometer (XRD) measurement were used to investigate the microstructure and crystallinity of the SSC films. The ESD technique is shown to be an efficient method in which the SOFCs' cathode film can be fabricated with the desired phases and microstructure.

• Journal of the Korean Geographical Society
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• v.49 no.2
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• pp.200-220
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• 2014

This study reexamines the old concept and reviews prevalent statements on Cenozoic vertical motions of the peninsula that have been uncritically repeated in our academia. The contents of this paper are redefinition of the notion, tilted flexure or warping, and a suggestion for a new time set and properties of the deformation, followed by a new model on its influencing factors and processes. In conclusion, the Cenozoic vertical motion of the Korean peninsula can be reified further with an epeirogenic movement of uplift in the east side-subsidence in the west side of the peninsula since the Neogene (23 Ma). However, the regional boundary for areas of uplift and subsidence is not likely in the Korean peninsula but broader farther to East China and the southern part of Russia. It can be best understood that mantle convection produced by subducting activities in the Western Pacific Subduction Zone causes the uplift and subsidence of earth surface around NE Asia. In addition, faultings in the upper lithosphere induced by in-situ plate boundary stresses accelerate regional uplift in the peninsula since the Quaternary. Controversies that are still standing such as current uplift movements along the western coast of the peninsula during the late Quaternary could be precisely discussed with future research providing detailed information on it.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.5
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• pp.146-153
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• 2009

Recently, the research relative to NGN(Next Generation Network) is progressing in 3GPP(The 3rd Generation Partnership Progect), IETF(Internet Engineering Task Force), and so on. Although user needs frequently mobility which is various service pattern, In accordance with the development of these various applications, IMS(IP Multimedia Subsystem) and hierarchical networks ie, Femtocell/WiBro/3G etc is constructed for more user demands which provide service in anytime, anywhere. It is necessary to optimum network selection criterion which consider to wireless signal quality add to user service profile and service network traffic balance. NGN also needs a method to perform heterogeneous handover and to constraint Ping-pong phenomenon when using existing terminal-based handover decision. This paper proposes scheme for network selection and heterogeneous handover procedure in hierarchical wireless multi-access network based on SIP-MIH(Session Initiation Protocol-Media Independent Handover) with IMS by using user service profile that the considerations are dealing with not only selection and registration of various access network but also easy of developing the terminal.

• Journal of the Microelectronics and Packaging Society
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• v.16 no.4
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• pp.33-39
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• 2009

A microlens array (MLA) was developed based on the wet-etched quartz substrate and coating of UV adhesive on the substrate for maskless lithography application. The developed MLA has the focal length of ${\sim}45\;{\mu}m$ and the spot size of ${\sim}1\;{\mu}m$. The spot size of the focused beam passing through the MLA was detected by CCD camera, and its intensity was monitored by beam profiler. Uniform spots with nearly identical intensities were observed on the focal plane when a beam passes through the fabricated MLA. The focal length was varied depending on thickness of the coated UV adhesive. The thicker the thickness of the UV adhesive was, the shorter the focal length of the MLA was. With a general mask aligner, UV beam focusing was tested onto photoresist (PR). The beams were well focused onto PR when UV passes through the MLA. Depending on the variable distances from the MLA, beam sizes onto PR were controlled. Even at high temperature for a long time, the performances of the MLA were not changed.

• Journal of Environmental Science International
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• v.5 no.6
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• pp.813-826
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• 1996

The toxic effects of aluminium (Al) on growth, chlorophyll content, $\delta-aminolevulinic$ acid dehydratase (ALAD) activity and anatomy of root and shoot were investigated in 7-day-old azuki bean (Vigna angularis) seedlings. Significant depressions in root elongation was observed in the low concentrations of Al (50, 100 $\muM)$ and increasing Al concentrations caused a sharp decline of root and shoot growth. The degree of inhibition was dependent upon Al supply. Exposure to 50 $\muM$ Al or more inhibited root elongation within 1 day. In the 50 $\muM$ Al treatments, a recovery of root growth was seen after 7 days exposure. In contrast, lateral root initials was little affected by Al exposure. Al toxicity symptoms and growth responses were more well developed in the roots than in the shoots. Analysis of Al localization in root cells by hematoxylin stAlning showed that Al entered root apices and accumulated in the epidermal and cortical cells immeadiately below the epidermis. There was a good positive correlation between the level of chlorophyll and ALAD activity. Increasing Al concentrations caused a decrease in total chlorophyll contents, accompanied by proportional changes in ALAD activity, suggesting a cootr-dinated reduction of a photosynthetic machinery. Al exerted specific influence on the morphology of root ann shoot. At higher concentrations of Al the roots induced drastic anatomical changes. The epidermal cells were disorganized or destructed while the cortical cells exhibited distortion of cell shape and/or disintegration. The diameter of root and transectional area of cortical cells decreased considerably with Al treatment. In the shoot Al also enhanced reduction of diameter of shoot and cell size. Gross anatomy of leaves treated with Al did not differ significantly from the controls, except for fewer and smaller chloroplast. Our results indicate that toxic effect of Al appear to be manifested primarily in roots and secondarily on shoots, and changes in root morphology are related to changes in the root growth patterns. Results are further discussed in re181ion to the findings in other plant species, and it is concluded that Al causes morphological, structural and, presumably, functional damage to the roots of the species investigated.

• Journal of The Korean Association For Science Education
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• v.35 no.3
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• pp.523-536
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• 2015

In this study, we analyzed the co-reflection of pre-service teacher community in three years of post-class discussions (PCD) on the basis of cultural historical activity theory in the case of an biological laboratory class program. We figured out the sociocultural elements of co-reflection of community using activity system suggested by $Engestr{\ddot{o}}m$. We also analyzed the aspect of reflection in terms of both 'the diversity of reflection subjects' and 'the practicality of reflection.' Finally, limitations of co-reflection were sought in a process of continuos circulation of reflection and practice. The results show that the sociocultural factors of 3-year-PCD changed, and in these changes, 'regular PCD,' 'introduction of tools for facilitating reflection,' 'transition of the subject in PCD from researcher to pre-service teachers' are remarkable. And in these process, co-reflection made positive progress since the content of reflection became diverse and practical. However, in some subjects such as 'managing time,' 'participation of students,' 'mentor's role (a kind of teaching manual),' reflective practice have not developed and similar patterns of discussion were repeated. From these results, we suggested ways of facilitating pre-service teacher community's co-reflection from the viewpoint of an activity system.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.4
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• pp.193-205
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• 2003

There has been so many research activities about robot soccer system in the many research fields, for example, intelligent control, communication, computer technology, sensor technology, image processing, mechatronics. Especially researchers research strategy for attacking in the field of strategy, and develop intelligent strategy. Then, soccer robots cannot defense completely and efficiently by using simple defense strategy. Therefore, intention extraction of attacker is needed for efficient defense. In this thesis, intention extractor of soccer robots is designed and developed based on FMMNN(Fuzzy Min-Max Neural networks ). First, intention for soccer robot system is defined, and intention extraction for soccer robot system is explained.. Next, FMMNN based intention extractor for soccer robot system is determined. FMMNN is one of the pattern classification method and have several advantages: on-line adaptation, short training time, soft decision. Therefore, FMMNN is suitable for soccer robot system having dynamic environment. Observer extracts attack intention of opponents by using this intention exactor, and this intention extractor is also used for analyzing strategy of opponent team. The capability of developed intention extractor is verified by simulation of 3 vs. 3 robot succor simulator. It was confirmed that the rates of intention extraction each experiment increase.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.4 s.316
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• pp.26-34
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• 2007

Intelligent projection system indicates a system that displays desired images on an arbitrary screen in an arbitrary environment using projector without noticeable image distortion. In recent years, projectors have become widespread and ubiquitous due to their increasing capabilities and declining cost. Moreover, the size of projectors is getting smaller and handhold projectors are emerging. Thanks to these advances, the demand for intelligent projection system has been significantly increased and the demand has led to remarkable progress of the related techniques or technologies to intelligent projection system However, there are still some environments (or conditions, mainly dynamic ones) that intelligent projections systems cannot handle and they have limited the application area of intelligent projection systems. This paper exemplifies such environments (e.g. specular screen, dynamic screen) and propose effective solutions (i.e. multiple overlapping projectors, complementary pattern embedding) for thor And the usefulness of the solutions is verified through experimental results and user evaluation. Notice that the environments are considered not simultaneously but independently because it is impossible to consider them simultaneously by simply combining the solutions for each. Acually, a totally different solution would be necessary to consider them simultaneously. Therefore, we expect that the proposed methods would largely extend the application area of intelligent projection systems except for severely arbitrary environment.

• Korean Journal of Environment and Ecology
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• v.1 no.1
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• pp.66-82
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• 1987

The user's composition of socia-economic characteristics in Bukhan Mountain National Park showed that male. twenties and students were 65.4 percent. 62.7 percent and 37.4 percent respectively by sex, age and occupation. In visiting purpose, the nature-oriented motive was 67.1 percent of the total. hut the picnic patterns as of neighbourhood park and the recreation patterns as of recreation ground were appeared simultaneously. In preferable place of visitors. the well-known mountain hut, camp sites and summits were prefered. The level of scenic satisfaction was 7.8 and comparatively high on considering the maximum level of 10.0. The level of total satisfaction. however, was no more than 6.3 owing to lack of accomodation facilities along trails, 63.4 percent of visitors were opposed to construction cable-car and visitors were anxious seriously about the nature deterioration. In Jeongnung valley, the number of users was the lagest, so that the maximum number of passangers a day attained to 20.000. The peak seasons of visiting were Spring and Fall, and the peak hours during a day was 10-11 hours A.M. and 3-5 hours P.M. Therefore partitioned spatial management in consideration of hiking pattern of nature park. picnic pattern as of neighbourhood park and recreation pattern as of recreation ground shall be necessary to solve the conflicts among functions.