• Korean Journal of Plant Resources
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• v.8 no.1
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• pp.41-46
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• 1995

This experiment was carried out to investigate the effects of temperature, light quality and gibberellic acid on the seed germination of Rhododendron weyrichii Max. Optimum temperature for germination was $20^{\circ}C$ at constant temperature, but the final germination rate at $15^{\circ}C$ was about the same with the rates were attained by alternating temperature under higher temperature such as $25^{\circ}C$ or $30^{\circ}C$. The germination rate was increased by yellow and red light treatments at $20^{\circ}C$, but green light treatment strongly inhibited seed germination at $25^{\circ}C$. Gibberellic acid substitutes light requirement for germination of R. weyrichii seeds.

• The Journal of the Petrological Society of Korea
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• v.2 no.2
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• pp.156-166
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• 1993

The volcanic stratigraphy and geochemistry of the Cretaceous volcanic rocks in the southern part of the Pusan showed that the volcanic rocks of the study area consist of alternating pyroclastic rocks and andesitic lavas, apparently constituting a thick volcanic sequence of a stratovolcano. The andesitic rocks contain augite, plagioclase, and hornblende as phenocrysts. Matrix minerals are augite, magnetite, hornblende, apatite. Mafic minerals, such as chlorite, epidote, sericite, and iron oxides occur as alteration products. Dacitic volcanic breccia and rhyolitic welded ash-flow tuff locally overlie the andesitic rocks. The rocks reported in the previous studies as andesitic breccia and andesite plot in the field of basalt, basaltic andesite, andesite, dacite and rhyolite, based on their chemical compositions. The volcanic rocks of the study area belong to the calc-alkaline series, and the andesitic rocks which are predominant in the area plot to the field of orogenic andesite.

• PNF and Movement
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• v.15 no.2
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• pp.125-132
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• 2017

Purpose: This study reviewed articles to identify the optimal rhythmic stabilization or stabilizing reversals application method for improving balance. Methods: The Cochrane, EBSCO, eArticle, Embase, DBpia, KISS, Medline, ProQuest, PubMed, SAGE, ScienceDirect, Scopus, Springer, and Wiley databases were used to search articles from 1990 to January 2017. The search terms included: "rhythmic stabilization" and "stabilizing reversals." Only experimental human studies (randomized controlled trials) that compared the effects of varying the optimal application of rhythmic stabilization or stabilizing reversals to improve balance were included in the review. Non-English language (except Korean) and unpublished studies were excluded. Results: During the research, 1,098 articles were initially identified. Of these articles, nine were randomized controlled trials. Of these nine articles, five were in English, and four were in Korean. In addition, three of the trials did not measure the patients' balance, two did not report the intensity and location of the resistance, and three performed the rhythmic stabilization incorrectly. Only one article met the inclusion and exclusion criteria. The remaining study evaluated the participants' performance of the alternating trunk flexor and extensor isometric contraction of the scapulae using the optimal resistance for 10 seconds in a sitting position. The participants completed three sets of eight repetitions with rest intervals of 30 seconds between the repetitions and 60 seconds between the sets. Conclusion: Due to the lack of the scientific research on the topic, this review may not provide the evidence needed to support the optimal application of rhythmic stabilization or stabilizing reversals to improve balance. Future research should consider the methodological quality to identify the proper rhythmic standardization and stabilizing reversals application method.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.5
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• pp.542-548
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• 2001

A robust, accurate, broad-band, alternating current sensor using fiber-optics is being developed as a part of optical over current protection relay system. The sensor uses the Faraday effect in optical fiber and polarimetric measurements tc sense electrical current. The current sensing coil consists of a length of twisted optical fiber and Faraday rotator mirror to suppress the linear birefringence effect. Due to its single-ended closed path structure, it can not only be easily installed to the target with great isolation from other fields in the vicinity, but the sensitivity can be increased by using multiple turns. This paper reports on the theoretical backgrounds of the sensor design and the preliminary experimental results.

• The Journal of Internal Korean Medicine
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• v.21 no.4
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• pp.575-581
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• 2000

Objective : Asthma is a lung disorder characterized by periodic attacks of wheezing alternating with periods of relatively normal breathing. And quality of life in asthmatic patients shows a tendency to decrease. So we had a clinical study whether if oriental medical treatment could improve their quality of life or not. Methods : The 15 cases were new patients that visited at division of respiratory system, department of internal medicine in Kyunghee medical center from the 1 st of July, 2000 to the 1 st of August. All of them were diagnosed as asthma and treated by western medical therapy. We used a Quality of Life Questionnaire for adult Korean Asthmatics(QLQAKA) and evaluated the results after two times answers, at an interval of two weeks. Results : The mean of the first answer was 2.84 marks and 3.36 ones after two weeks. If there is a difference of over 0.5 points between the two, we can admit significant effect. After the asthmatic patients treated by oriental medical therapy, they gained a difference of 0.52 points, 10.4%. Conclusions : We suggest that oriental medical therapy can improve the quality of life of asthmatic patients arid we can alternate side effects of western medical therapy with oriental one. if they carry out two different treatments at the same time.

• Journal of The Korean Astronomical Society
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• v.51 no.1
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• pp.5-16
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• 2018

We investigate the escape of $Ly{\beta}$ from emission nebulae with a significant population of excited hydrogen atoms in the level n = 2, rendering them optically thick in $H{\alpha}$. The transfer of $Ly{\beta}$ line photons in these optically thick regions is complicated by the presence of another scattering channel leading to re-emission of $H{\alpha}$, alternating their identities between $Ly{\beta}$ and $H{\alpha}$. In this work, we develop a Monte Carlo code to simulate the transfer of $Ly{\beta}$ line photons incorporating the scattering channel into $H{\alpha}$. Both $H{\alpha}$ and $Ly{\beta}$ lines are formed through diffusion in frequency space, where a line photon enters the wing regime after a fairly large number of resonance scatterings with hydrogen atoms. Various line profiles of $H{\alpha}$ and $Ly{\beta}$ emergent from our model nebulae are presented. It is argued that the electron temperature is a critical parameter which controls the flux ratio of emergent $Ly{\beta}$ and $H{\alpha}$. Specifically for $T\;=\;3{\times}10^4\;K$ and $H{\alpha}$ line center optical depth $\tau{\alpha}\;=\;10$, the number flux ratio of emergent $Ly{\beta}$ and $H{\alpha}$ is ~ 49 percent, which is quite significant. We propose that the leaking $Ly{\beta}$ can be an interesting source for the formation of $H{\alpha}$ wings observed in many symbiotic stars and active galactic nuclei. Similar broad $H{\alpha}$ wings are also expected in $Ly{\alpha}$ emitting halos found in the early universe, which can be potentially probed by the James Webb Telescope in the future.

• The Journal of Korean Association of Computer Education
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• v.4 no.1
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• pp.127-134
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• 2001

Many teachers at vocational high schools have had difficulties overcoming the gap between what students know and what students have to achieve in many topics. Mathematics is toughest of all, since most of textbooks in electronics are assuming student's basic knowledge in math. Considering that many students with very low achievements are entering vocational high schools, reality is far from such assumption. Inevitably, we have to face two difficult questions; do we have enough time to teach these kids all the math that they need in two years? If not, what alternatives we should adopt? We just do not have enough time and therefore find out a way to cope with harsh reality. According to our preliminary study, we suggest that multimedia-based CAI may be the best way to attack this problem. From hardware point of view, fortunately, many of vocational high schools are reasonably equipped for multimedia-based education. However there have been hardly any effort to develop courseware for vocational education in Korea. In this paper, a CAI title for learning basic characteristics of alternating current has been designed and implemented. The developed multimedia-based CAI title has been applied with respect to first grade students at local vocational high schools. A survey after classes shows that CAI could help student feel much comfortable with Basic Electricity course and grasp physical understanding much easily. Accordingly we conclude that classes adopting CAI would be of great help to put education in vocational high schools on the right track.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.10
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• pp.699-705
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• 2001

Six types of planar thermal converters from TC 1 to TC 6 were designed and fabricated for the purpose of being used as practical standards to alternating current. The respective voltage responses in air and in a vacuum of TC 6, which has the smallest thermal loss, were about 4.03mV/mW and about 6.38 mV/mW. Thermal time constant of TC 6, which has also the smallest heater thermal inertia, was about 8 ms. The respective variations of AC-DC voltage and current transfer errors from sample to sample, which were measured by FRDC(fast reversed DC) method, were about $\pm$0.41 ~$\pm$0.85 ppm and about $\pm$0.15~$\pm$1.16 ppm in the frequent range of 40 Hz~10 KHz with appling 1 V and 5 mA rms sine waves to the converters. All converters investigated exhibited sufficiently low AC-DC transfer errors to be used as practical standards.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.59-64
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• 2009

In this paper, the design of a new bandstop filter with an ultra-wide stopband is proposed using the metamaterial CRLH-TL. Instead of conventional periodic structures and multi-staged CRLH-TLs, extremely small one-cell type is adopted to circumvent the setbacks of conventional filters such as the lengthened ${\lambda}_g/2$-resonator ones or alternating impedance lowpass filter, and relatively slow skirt. Besides, for a very broad stopband, a strong coupling structure including stepped impedances is suggested and the zero-order resonance is made for effective size-reduction. The validity of the proposed design is proven through the fabrication and measurement, showing the overall size less than ${\lambda}_g/10$, the stopband wider than 12 GHz, 0.7 dB of the insertion loss.

• 한국전산유체공학회:학술대회논문집
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• 1996.05a
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• pp.52-57
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• 1996

Mixing is most important for developing an electric washer which transforms angular momentum from rotating solid wall to laundry clothes inside it. For magnification of this mixing effect, some inventions are introduced to washing machine system, i. e., washing plate, washing rod, and even for washing cap in a model of a Korean manufacture. However, the previous efforts show dissatisfaction up till now. In this paper, a triumph to enhance mixing effects to increase washing performance is presented and verified by numerical investigation. The present model to simulate a washing tub is the simple circular cylinder with two endwall disks which is completely filled with a viscous liquid. The present improvement is to change mounting position of a bottom disk of the model cylinder. Therefore, the aim of this work just proposes a new idea, which is numerically inspected, to a producer of washing machine, In detail, this invention is alternating the mounting position of a rotating bottom disk. Actually skewed pulsator is placed in steady of a flat disk, so the two endwall disks at top and bottom are not in parallel. The angle between an inclined bottom disk and the horizontal plane is fixed as 5 degree and physical domain to consider poses a sliced cylinder. Flow fields in both a right circular cylinder and the present improved model are fully depicted by numerical integration on a body fitted nonorthogonal regular uniform grid system. Numerical data to explain flow structure are plotted for understanding of the effects of the inclined disk. Also enhanced mixing effects by the inclined rotating disk are gauged by accurate numerical data used in this work.