• Journal of Sensor Science and Technology
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• v.21 no.4
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• pp.298-302
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• 2012

This paper describes the design and fabrication of a low frequency vibration driven high-efficiency electromagnetic energy harvester based on FR(Flame Resistance)-4 spring which converts mechanical energy into useful electrical power. The fabricated generator consists of a vertically polarized NdFeB permanent magnet attached to the center of spring and a planar type copper coil which has higher efficiency compare with cylindrical type coil. ANSYS finite analysis and Matlab were used to determine the resonance frequency and output power. The generator is capable of producing up to 1.36 $V_{pp}$ at 9 Hz, which has the maximum power of 639 ${\mu}W$ with a load resistance of $3.25k{\Omega}$.

• Journal of the Korean earth science society
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• v.30 no.5
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• pp.646-659
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• 2009

The early Ordovician graptolites from the upper part (Tumok Member) of the Mungok Formation of the Namaeri and Baeiljae sections at Yeongwol consist of five species belonging to five genera. They are Adelograptus cf. tenellus, Callograptus sp., Dendrograptus suni, Dictyonema sp., and Psigraptus jacksoni. Of these 5 species, Psigraptus is the most excellent index fossil for international correlation with the early Ordovician strata. Adelograptus cf. tenellus from the Mungok Formation of the Namaeri and Baeiljae sections is also recognized with especially short stipe relative to Adelograptus tenellus. Three graptolite zones (such as Adelograptus, Psigraptus, and Dendroid type zones) are correlated with those of Canada, Australia, and China, respectively. The upper part of the Mungok Formation is assigned to the late Tremadocian.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.2
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• pp.200-207
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• 2007

In vitro rumen incubation studies were conducted to determine effects of initial pH on bacterial attachment and fiber digestion. Ruminal fluid pH was adjusted to 5.7, 6.2 and 6.7, and three major fibrolytic bacteria attached to rice straw in the mixed culture were quantified with real-time PCR. The numbers of attached and unattached Fibrobacter succinogenes, Ruminococcus flavefaciens and Ruminocococcus albus were lower (p<0.05) at initial pH of 5.7 without significant difference between those at higher initial pH. Lowering incubation media pH to 5.7 also increased bacterial numbers detached from substrate regardless of bacterial species. Dry matter digestibility, gas accumulation and total VFA production were pH-dependent. Unlike bacterial attachment, maintaining an initial pH of 6.7 increased digestion over initial pH of 6.2. After 48 h in vitro rumen fermentation, average increases in DM digestion, gas accumulation, and total VFA production at initial pH of 6.2 and 6.7 were 2.8 and 4.4, 2.0 and 3.0, and 1.2 and 1.6 times those at initial pH of 5.7, respectively. The lag time to reach above 2% DM digestibility at low initial pH was taken more times (8 h) than at high and middle initial pH (4 h). Current data clearly indicate that ruminal pH is one of the important determinants of fiber digestion, which is modulated via the effect on bacterial attachment to fiber substrates.

• Journal of The Korean Association For Science Education
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• v.5 no.1
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• pp.63-79
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• 1985

The purpose of our survey study was to investigate the status on perception and actual state toward science educational evaluation and objectives of middle school science teachers in Pusan. The perception and actual state were surveyed by the questionaire which was developed by Jong-Ok Woo et. al. We developed two kinds of questionaire. One is designed to use Likert type scale and is composed of two main category(SE; Science educational evaluation, SO; Science educational objectives) which contains 21 question items, and the other has 16 question items From 313 science teacger's responses of 75 middle schools in pusan, the tendency. of total(SE+SO) and each sub category, and the contrast with their background and actual state were analized by SPSS program of KAIST. Some results of our survey study can be summarized as follows; 1. Total tendency of science educational evaluation(SE) and objectives(SO) of middle school science teachers in pusan shows a positive and right tendency of conception in general(m-85.8/100). 2. Tendency of SE(m-87.8/100) are slightly higher than SO(m-81.7/100). At the level of 5% significance, there are correlated but shows low correlation (r=0.12(4). 3. In each correlation toward total tendency(SE+SO), SE is highly correlated(r-0.8486) but SO is moderately correlated(r=0.6297) at the level of 0.1% significance. 4. Tendencies of 5sub category (PE, PC, PD, PO, PB) shows considerably right tendencies (m=$73.4/100{\sim}92.7/100$), there are moderately correlated foward total tendency(SE+SO) at the level of 0.1% significance (r=$0.49{\sim}0.60$). 5. At the level of 5%significance, total means are no differences which their background(Sex, Final alma mate, Major, Difference of training), but there is differences to teaching career at the level of 5% significance.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.72.1-72.1
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• 2013

Camera for QUasars in EArly uNiverse (CQUEAN) is an optical CCD camera, developed by Center for Exploration of Origin of the Universe (CEOU), which is now searching for high red shift quasar candidates. It has been operated since 2010, attached to the 2.1m Otto Struve telescope at the McDonald Observatory, USA. Based on the previous operation experiences, we present CQUEAN II system design which has a new filter wheel allowing with 20 narrow band filters. In addition, the auto guiding system will be rearranged and the interfacing units between the telescope and the instrument will become stabilized.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.221-227
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• 2019

One of the important requirements for the application of reduced activation ferritic/martensitic steel is to retain proper mechanical properties in irradiation and high temperature conditions. In order to simulate the impact toughness with the effect of temperature and irradiation, a simulation model based on energy balance method consisted of crack initiation, plastic propagation and cleavage propagation stages was established. The effect of temperature on impact toughness was analyzed by the model and the trend of the simulation results was basicly consistent with the previous experimental results of CLAM steels. The load-displacement curve was simulated to express the low temperature ductile-brittle transition. The effect of grain size and inclusion was analyzed by the model, which was consistent with classical experiment results. The transgranular-intergranular transformation in brittle materials was also simulated.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.2
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• pp.308-315
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• 2014

The aims of this study are to analysis about surface muscle activity of lower and upper musculus erector spinae according to walkers form. The subjects of the current step is inconvenient to use a walker and five people over the age of 65 valid samples were selected as final. All the subjects were measured in three forms. Wireless EMG muscle activity is a measure of surface measurements were measured using a system, both musculus vastus lateralis, outside the erector spinae muscle, musculus biceps femoris, gastrocnemius muscle was attached to the channel electrodes. According to the results, First, gastrocnemius muscle activity showed significant differences by type of gait. Second, the muscle activity of the erector spinae muscle walking showed significant differences by type, side grip type showed the lowest muscle activity. Consequently, the present study is the efficient use of the four-wheel walker will provide the baseline data.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.436-440
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• 2008

Among those various facilities attached to the school building, the Auditorium is being utilized for not only the Exercise Activity but also for many purposes such as Culture, Public Performance, Education, Assembly and so on. In order to utilize in maximum such function of the multipurpose auditorium, an adequate acoustic design with regard to the Clarity of Voice and Music in accordance with its use-purpose should be accompanied. However, as the most part of multipurpose auditoriums is designed with high ceiling-height by its peculiar character, and due to use of the material of strong reflexibility, it is appearing the defect that excessively exposes the reverberation of sound. In order to make out an optimal acoustic condition within the broad space such as an auditorium, the acoustic characteristics must be considered from the planning stage, however in the most case, those acoustic problems are being settled through the repair works after construction. On such viewpoint, this Study intends to analyze the room acoustic characteristics from the planning stage using a computer simulation based on the blueprint of multipurpose auditorium in S High School located in Gwangju. It is considered that the material analyzed in such way could be practically applied as a fundamental material enables to improve the acoustic capability when a similar broad space is planned hereafter.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.619-626
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• 2012

The purpose of this study is to compare and analyze the utilization state of smart devices and the recognition level of educational application development of the general high school and the specialized high school. Specialized high school students preferred the utilization of smart devices more and daily spent on the devices more time than general high school students. As for the learning field, language for the general high school and the certificate of qualification for the specialized high school were shown high. The merit of smart device utilization is the use of spare time and its infrastructure was most required. The most expected content is a video lecture for the general high school and cooperative learning for the specialized high school and the most satisfied point was mobility. The specialized high school students feel more necessity about the application development for culinary education and had a plan to utilize it more and more preferred practice videos. As for the food development areas, the general high school students hoped simple food and the specialized high school students did cooking technician food and they both hoped the application to be uploaded in portal sites and the department homepage. The application development for culinary education is required to focus simulation learning including practice videos and cooking recipes and add an evaluation function to check the academic achievement levels. It is required to provide the subject goals of each course and concrete information on solving problems. Contents including video, music, texts need to be attached to improve learning immersion. There should be the beginning and development of a lesson and the flow of arrangement and communication between main bodies of learning should be improved by utilization of SNS cooperative learning services.

• Korean Journal of Metals and Materials
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• v.48 no.2
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• pp.180-186
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• 2010

For the application of field emission display (FED), it is essential to develop a carbon nanotube (CNT) cathode with high emission current density. In this study, we developed and demonstrated a post-heat treatment (PHT) process to improve field emission properties of CNT cathodes. Since the PHT is intended to burn out organic materials covering the CNTs, the PHT was carried out by heating samples at a high temperature in an atmosphere. The PHT process is applied for samples processed by surface treatment with an adhesive tape. Compared to samples prior to the PHT, samples after the PHT at $360^{\circ}C$ showed about 17% improvement in emission current density. The major reason for the increased current density is mainly the increased aspect ratio of the CNTs because of the removal of the adhesive organic residues covering the CNTs, which were attached on the CNT surfaces during the surface treatment using the adhesive taping method.