• Journal of Plant Biology
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• v.28 no.2
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• pp.105-118
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• 1985

This study was carried out to investigate the epidermal structure and types of stomata on the upper and lower surfaces of the leaves in six species and one variety belonging to Korean Crassulaceae. The shape of epidermal cells was polygonal, isodiametric, or elongated. The cell wall was thick, sinuous or deeply sinuous. The subsidiary cell wall was thin or mostly arched. The cytolith-containing cells were found in Orostachys japonicus. The distribution of stomata was more on the upper surface than on the lower surface in the leaves of O. japonicus and Sedum sarmentosum. The stomata in the other species were less on the upper surface than on the lower surface, and stomatal size was different in each species. The great majority of stomatal types was the helico-eumesogenous type. This type was subdivided into two, parahelico-eumesogenous type and diahelico-eumesogenous type by us on the basis of the angle of division of guard mother cell and the long axis of the last-formed subsidiary cells. Sometimes allelo-eumesogenous type as well as aniso-eumesogenous type was found. The tetra-eumesogenous type with four mesogenous subsidiary cells was rarely observed. It was observed that the varieties of aniso-eumesogenous type with one to three subsidiary cells and one helix of subsidiary cells were developed by the secondary division of subsidiary cells of aniso-eumesogenous stoma. The compound shape of helico-eumesogenous stomata was found. Five new kinds of stomatal types were observed as follows; the helico-tetra-eumesogenous type, the coallelohelico-eumesogenous type, the cohelico-allelo-eumesogenous type, the duplotetra-eumesogenous type, and the aniso-euperigenous type. These types were reported here in the vascular plants for the first time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.567-575
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• 2018

This study examined a pile foundation using a spiral pile. To maintain the structural safely, a foundation for connecting the ground and the ground structure is needed. On the other hand, noise and vibration, etc. cause problems when constructing a foundation on adjacent structures or urban areas. A study of the spiral foundation of a new shape with low vibration and noise was carried out to solve these problems. A study of pile foundations was carried out on a scaled model test and compared with the results of Meyerhof's bearing capacity theory. The scaled model test results showed that the bearing capacity increases with increasing pitch angle and length of the spiral pile. To verify the measured bearing capacity in a test with theoretical results, the bearing capacity of the actual spiral pile and scaled model pile were examined and compared. The ultimate bearing capacity of the spiral pile can be increased by increasing the foundation length and pitch angle. This study complements existing foundation construction problems and contributes to a better effect and safety.

• Journal of Drive and Control
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• v.12 no.4
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• pp.1-7
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• 2015

In this study, a spiral valve which is used with a cryogenic linear expander and composed of plural plate coil shapes was examined. Generally, a spiral valve is well known for having excellent efficiency and low noise characteristics. In order to determine the movement characteristics and to investigate the limit of valve displacement, the stress variations according to the changes of operating pressure, displacement and workable temperature are discussed. From this examination, it is considered that the results of this study will significantly facilitate the design and development of a spiral valve for the cryogenic linear expander.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.163-169
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• 2016

In this paper, we miniaturized the loop and coil in magnetic resonance wireless power transfer(MR-WPT) system for application to the small mobile device. The proposed disk type double coil resonator was designed to cause resonance at 6.87 MHz. It is composed of thin copper on both-side of acrylic substrate structured 2 mm width, 1 mm pitch and 8 turns. The outer radius of spiral coil pattern is 9 cm. And the proposed loop was made of the copper wire 5 mm diameter of cross-section. The size of loop is 10 cm diameter. For resonance at 6.87 MHz, the capacitor with 3,300 pF was connected in series on the loop. We rearranged the resonators and organized several WPT systems which is rearranged by resonators. The highest transfer efficiency of miniaturized WPT system was 35.67 %. This proposed design of spiral double coil will contribute to make resonator smaller for appling small and thin mobile device.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.524-530
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• 2009

In the post-beam structure, the infilled light-frame construction provides most shear strengths. Shear properties of the light-frame structure can be estimated from the shear properties of nailed connection for the sheathings, and those of nailed connections can be done from nail bending strengths. For the basic study to predict the yield strength and the slip modulus of a nailed sheathing shear wall, those of a nailed joint were examined from nail bending strengths. To estimate shear properties of a nailed connection, referenced bearing strength and bearing constant for the wood members and the experimental nail bending strengths of the helically threaded nail were applied. The yield strength using the diameter at grooves instead of shank diameter was well coincided with the experimental value, but the slip modulus was estimated much smaller. The effective factors, specific gravity for the main member, withdrawal by nail head diameter to the side member, and embedment and moment at the nail head were considered, and further examinations are needed for the precise prediction of the nailed connections.

• Applied Microscopy
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• v.41 no.2
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• pp.123-128
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• 2011

The micropyles on the prefertilized and artificial fertilized eggs of Epinephelus fasciatus were investigated using scanning electron microscope (SEM). The micropyles ($6.6{\pm}0.41\;{\mu}m$) of E. fasciatus eggs were found in the animal pole and theirs shape were observed as a flat crateriform of cylindrical shape. The micropylar vestibule arranged by 6~7 thickened spiral annuli on the ridge and contributed to differentiate and form fertilization cone for blocking to polyspermy by presenting swollen vestibule structure. As E. fasciatus eggs was pelagic, so chorionic surface was an uneven structures such as circular and fillar form nodules. Especially, various pores (0.15~0.55 ${\mu}m$, 230~270 pores) distributed at the only around micropyles, those pores radiately exhibited regular projection structures showing gill filament-shape. These ultrastructural characters of E. fasciatus eggs can be utilized in a taxonomical cue of grouper species.

• Journal of the Korea Concrete Institute
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• v.23 no.2
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• pp.195-201
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• 2011

This paper estimates the structural performance of spirally confined concrete having electric arc furnace (EAF) oxidizing slag aggregates. The EAF oxidizing slag is a by-product generated from iron and steel industry. The EAF oxidizing slag have been largely put to low-value-added uses due to its expansive properties of the free-CaO and free-MgO. Recently, this problem has been solved by the advances in steelmaking technology and thereby stabilizing EAF oxidizing slag aggregate. To verify the application of the EAF oxidizing slag aggregate to the structural concrete usage, a total of 27 cylindrical specimens with a diameter of 150 mm and a height of 300 mm were cast and tested. The test parameters were aggregate type and spiral reinforcement yield strength. Experimental results showed that the structural performance of specimens with EAF oxidizing slag aggregates was equivalent to that of confined concrete with natural aggregates.

• The Journal of Korean Association of Computer Education
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• v.17 no.6
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• pp.59-69
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• 2014

Following the announcement made in 2007of the information education curriculum for high schools, India followed through with a similar announcement in June 2013 for an elementary school curriculum to be linked with that of the high schools. As a characteristic feature of India's educational curriculum, the structure is "helical" in nature, while interaction between teachers and students is emphasized as a key method for education. During the past few years India has revised its educational curriculum based on Bruner's 'Structure of Knowledge,' which has changed the paradigm of the nation's educational curriculum. This study analyzed India's educational curriculum that aims at a helical structure and, at the same time, emphasizes 'narrative' thinking in schools. The goal of this study is to discover possible suggestions or implications for Korea's information education curriculum by analyzing India's education that concurrently seeks to employ 'Structure of Knowledge' and 'Narrative' theories in a single educational curriculum.

• Journal of Educational Research in Mathematics
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• v.13 no.1
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• pp.95-106
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• 2003

This study attempts to identify the characteristics of the structure of mathematics textbooks of North Korean high schools. The previous researches on the mathematics textbooks of North Korea show that North Korean mathematics textbooks have a linear structure, which is different from a spiral structure of South Korean textbooks. However, this study found that the textbooks of North Korea published after 1994 indicate that some sections reveal a spiral structure. In addition, most sections of North Korean mathematics textbooks are collectively composed, particularly so in the section of algebra.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.541-547
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• 2010

This document presents the research and result about localization of the fiber-based launching canister of rolling missile which has helical rails. This document is about the technical process development which is included with the manufacturing of helical rails and application of the flame spaying which is different with other the fiber-based launching canister in korea. and And this document is about quality Assurance procedure through the qualification test and structural evaluation in conditions that the canister has to have in real shipboard environment.