• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.95-102
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• 2011

The CFT columns used in thin-walled steel tubes can be more economical, because it was expected the increase of strength by restriction for the local buckling of steel tubes. The purpose of this paper is to review feasibility of existing design formula and verify the applicability limit of width-to-thickness ratio for increasing the strength of rectangular CFT columns. As the main parameters of experiments, width-to-thickness ratios of steel tube, height of rectangular concrete columns, and concrete filled or not. The strength of concrete are selected to 90MPa. From the test results, the confinement effect of steel tube on the compressive strength of infilled concrete is remarkably appeared in the thin-walled rectangular steel tube columns infilled wih high strength concrete. By the non-linear analysis, the axial strength from experiment result was given higher than analysis result for all CFT stub columns.

• Journal of the Korean Home Economics Association
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• v.20 no.4
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• pp.53-67
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• 1982

Physical measurements of 181 Korean elderly women, aged 60 through 79, living in the Seoul area, were taken in 1981 in order to analyze their body types and to study clothing construction according to their body types. The study was composed of 117 items in all; 35 items in measurements, 1 items in Rohrer index, 68 items in physical index to stature and bust girth, and 14 items in proportion, Coefficients of correlation among body dimensions were used. The results from this analysis are as follows: 1) The most significant changes in body dimensions in advanced age were the decrease of bust height and the increase of both abdomen girth and waist girth. 2) Distinct physical changes did not appear until advanced senescence(70~79 years of age). 3) In the three somatotype groups(thin, average, and plump) categorized by their Rohrer index, the dimensions that remained unchanged in senescence were back waist length and front waist length ; the dimensions that varied most significantly in senescence were the waist measurements. 4) As a result of the analysis of coefficients of correlation among the body dimensions of the 3 figure groups categorized by the Rohrer index, the fundamental dimensions for establishing the size of ready-to-wear garments of elderly women were the stature, bust girth and center back length in upper garments. 5) The result of the analysis of physical index and proportion of the 3 figure groups showed that the more plump a figure might be, the ratio of depth to width measurements increased; the back waist height was higher and trunk enlarged. 6) The 9 figure categorized by their Rohrer index and stature showed that the percentage of women in the category of“normal figure”decreased more in advanced senescence than during early senescence. 7) An analysis of variation of the 9 figure groups, the stature and other items for a short and thin figure were the smallest, and for a tall and plump figure, the largest.

• Archives of design research
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• v.17 no.2
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• pp.135-146
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• 2004

The street landscape image is through complex experience of psychological factor by the visionary experience and physical factor by recognize a street's structure. Therefore, the need for analyz-ing and evaluating the psychological and physical aspect of street view was aroused, and how much it has an effect on the outcome. Above all, a definite street standard of a region in its characteristics was selected to analyze the street characteristics of a region (commercial, business, and complex area). A questionnaire was used to measure psychological information felt in a street area. As a result, the street image holds similar characteristics according to regional characteristics and the amenity and busy condition play a major role in having the effect. To know of the effect of street of a region that is known to cause the busy in a region, the discriminant analysis was made between the selected regions to analyze the difference. As a result, the difference of the width of street, ratio of widths of sidewalk and driveway, the ratio of height of a building and width of street, and the difference of tree-planting ratio were main factors which helped to feel more of the contrary of street in a region. Current research has helped to make more precise analysis and evaluation of all kinds of street images, and suggested different means of having more live image in a street region through physical factors. To create more the busy in a region, it is considered that analyzing the image of a street would be used more.

• Korean Journal of Environment and Ecology
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• v.23 no.4
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• pp.365-375
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• 2009

The growth characteristics of Pinus thunbergii windbreak forest around Goosipo Beach, Sangha-Myon, Gochang-Gun, Jeollabuk-Do have been investigated, and the results are summarized as follows. The soil in the site was light acid sand with pH 5.7, and the mean sodium concentration of soils was 1.42dS/m. The tree diameter, height, crown width, and shape ratio(Height/DBH) were better with tree density was coming lower. Especially, the rate of shape ratio under 60 was more in sites with low tree density. This demonstrated that the trees have grown more soundly when the tree density was lower. The direction of main winds and distribution ratio of tree inclination had a correlation. The inclined trees are seemed to be influenced by main winds when they were younger and by Typhoon partly. Eighty one vascular plant species were found in the sites, and more number of herbaceous plants (57 taxa) lived there than woody plants (24 taxa). And more plant species of dune were found at the site where dune have developed well. Some thinning works need at high tree density areas in order to ensure effects of coastal windbreak.

• Tunnel and Underground Space
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• v.23 no.4
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• pp.308-318
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• 2013

Thermal stratification in heat stores is essential to improve the efficiency of energy storage systems and deliver more useful energy on demand. It is generally well known that the degree of thermal stratification in heat stores varies depending on the aspect ratio (the height-to-width ratio) and size of the stores. The present study aims to investigate the effect of the aspect ratio and storage volume of rock caverns for storing hot water on thermal stratification in the caverns and heat loss to the surroundings. Heat transfer simulations using a computational fluid dynamics code, FLUENT were performed at different aspect ratios and storage volumes of rock caverns. The variation of thermal stratification with respect to time was examined using an index to quantify the degree of stratification, and the heat loss to the surroundings was evaluated. The results of the numerical simulations demonstrated that the thermal stratification in rock caverns was improved by increasing the aspect ratio, but this effect was not remarkable beyond an aspect ratio of 3-4. When the storage volume of rock caverns was large, a higher thermal stratification was maintained for a relatively longer time compared to caverns with a small storage volume, but the difference in thermal stratification between the two cases tended to decrease as the aspect ratio became larger. In addition, the numerical results showed that the heat loss to the surrounding rock tended to increase with an increase in aspect ratio because the surface area of rock caverns increased as the aspect ratio became larger. The total heat loss from multiple small caverns with a reduced storage volume per cavern was larger compared to a single cavern with the same total storage volume as that of the multiple caverns.

• Steel and Composite Structures
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• v.32 no.2
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• pp.265-279
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• 2019

The self-centering capacity and energy dissipation performance have been recognized critically for increasing the seismic performance of structures. This paper presents an innovative steel moment frame with self-centering steel reinforced concrete (SRC) wall panel incorporating replaceable energy dissipation devices (SF-SCWD). The self-centering mechanism and energy dissipation mechanism of the structure were validated by cyclic tests. The earthquake resilience of wall panel has the ability to limit structural damage and residual drift, while the energy dissipation devices located at wall toes are used to dissipate energy and reduce the seismic response. The oriented post-tensioned strands provide additional overturning force resistance and help to reduce residual drift. The main parameters were studied by numerical analysis to understand the complex structural behavior of this new system, such as initial stress of post-tensioning strands, yield strength of damper plates and height-width ratio of the wall panel. The static push-over analysis was conducted to investigate the failure process of the SF-SCWD. Moreover, nonlinear time history analysis of the 6-story frame was carried out, which confirmed the availability of the proposed structures in permanent drift mitigation.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.50.2-50.2
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• 2019

Understanding three-dimensional structure and parameters (e.g., radial velocity, angular width, source location and density) of coronal mass ejections (CMEs) is essential for space weather forecast. In this study, we determine CME mean density in solar corona and near the Earth. We select 38 halo CMEs, which have the corresponding interplanetary CMEs (ICMEs), by SOHO/LASCO from 2000 to 2014. To estimate a CME volume, we assume that a CME structure is a full ice-cream cone which is a symmetrical circular cone combined with a hemisphere. We derive CME mean density as a function of radial height, which are approximately fitted to power-law functions. The average of power-law indexes is about 2.1 in the LASCO C3 field of view. We also obtain power-law functions for both CME mean density at 21 solar radii and ICME mean density at 1AU, with the average power-law index of 2.6. We estimate a ratio of CME density to background density based on the Leblanc et al.(1998) at 21 solar radii. Interestingly, the average of the ratios is 4.0, which is the same as a default value used in the WSA-ENLIL model.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.3
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• pp.235-244
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• 1996

This experiment was carried out to evaluate the effect of pasture type on behavior pattern, change of body type and daily gain of Korean native goat at the College of Natural Science of Kon-KuK University in Chungju. The results are summarized as follows : Relative coverage of native herbage at the pasture area was 62% in initial grazing period and that final grazing period decreased by 36%. while pasture plants increased from 17 to 42%. In brush area, Quercus serrata. Quercus dentutu, Prunus surgenrii and Rhus vemicrflua of high palatability decreased with increase in grazing period. but Rhododendron mucronulatum and Rhodendrorl schlippenbachii of low palatability tended to increase. Average crude protein content at the pasture area(12.3Q) during grazing period was higher than that at the brush area(10.2). However, ADF and NDF content was lower than brush area. Ca, Mg and Na of mineral content showed highly at the brush area during the grazing period. but Na showed highly at the pasture area. Eating time Korean native goat was not different between pasture area(369 min.) and brush area(361 min.), but ruminating time showed highly at the pasture area(441 min.). Average ratio of GTlRT at the pasture and brush area was not different m 0.88 and 0.87, respectively. All body type(withers height, body length, shin circum, hip height, hip width and chest girth) showed highly that pasture area compared to brush area during the grazing periods. The daily liveweight gain showed 60.6 and 48.98 at the pasture and brush area, respectively.

• Structural Engineering and Mechanics
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• v.72 no.1
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• pp.99-111
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• 2019

To investigate the seismic performance of long-span partially earth-anchored cable-stayed bridge, a super long-span partially earth-anchored cable-stayed bridge scheme with main span of 1400m is taken as example, structural response of the bridge under E1 seismic action is investigated numerically by the multimode seismic response spectrum and time-history analysis, seismic behavior and also the effect of structural geometric nonlinearity on the seismic responses of super long-span partially earth-anchored cable-stayed bridges are revealed. The seismic responses are also compared to those of a fully self-anchored cable-stayed bridge with the same main span. The effects of structural parameters including the earth-anchored girder length, the girder width, the girder depth, the tower height to span ratio, the inclination of earth-anchored cables, the installation of auxiliary piers in the side spans and the connection between tower and girder on the seismic responses of partially ground-anchored cable-stayed bridges are investigated, and their reasonable values are also discussed in combination with static performance and structural stability. The results show that the horizontal seismic excitation produces significant seismic responses of the girder and tower, the seismic responses of the towers are greater than those of the girder, and thus the tower becomes the key structural member of seismic design, and more attentions should be paid to seismic design of these sections including the tower bottom, the tower and girder at the junction of tower and girder, the girder at the auxiliary piers in side spans; structural geometric nonlinearity has significant influence on the seismic responses of the bridge, and thus the nonlinear time history analysis is proposed to predict the seismic responses of super long-span partially earth-anchored cable-stayed bridges; as compared to the fully self-anchored cable-stayed bridge with the same main span, several stay cables in the side spans are changed to be earth-anchored, structural stiffness and natural frequency are both increased, the seismic responses of the towers and the longitudinal displacement of the girder are significantly reduced, structural seismic performance is improved, and therefore the partially earth-anchored cable-stayed bridge provides an ideal structural solution for super long-span cable-stayed bridges with kilometer-scale main span; under the case that the ratio of earth-anchored girder length to span is about 0.3, the wider and higher girder is employed, the tower height-to-span ratio is about 0.2, the larger inclination is set for the earth-anchored cables, 1 to 2 auxiliary piers are installed in each of the side spans and the fully floating system is employed, better overall structural performance is achieved for long-span partially earth-anchored cable-stayed bridges.

• Applied Microscopy
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• v.42 no.3
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• pp.124-128
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• 2012

Leaf surface structures were investigated in the Chinese juniper Juniperus chinensis by scanning electron microscopy. Adult scale leaves were collected from the tree, air-dried at room temperature, and sputter-coated with gold without further specimen preparation. Approximately fi ve stomata were locally distributed and arranged in clusters on the leaf surface. Stomata were ovoid and ca. 40 ${\mu}m$ long. The epicuticular wax structures of J. chinensis leaves were tubules and platelets. Numerous tubules were evident on the leaf regions where stomata were found. The tubules were cylindrical, straight, and ca. 1 ${\mu}m$ in length. They almost clothed the stomatal guard cells, and occluded the slit-shaped stomatal apertures. Moreover, the wax ridges were flat crystalloids that were connected to the surface by their narrow side. They did not have distinct edges, and their width/height ratio varied. In particular, the wax ridges could be discerned on the leaf regions where stomata were not present nearby. Since the wax ridges did not have distinct edges on their margin, they were identified as platelets. Instances were noted where platelets were oriented either parallel to each other or perpendicular to the cuticle surface. These results can be used in biomimetics to design the hierarchical structures for mimicking the plant innate properties such as hydrophobicity and self-cleaning effects of the leaf surface.