• Geomechanics and Engineering
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• v.36 no.3
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• pp.277-293
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• 2024

Shored Mechanically Stabilized Earth (SMSE) walls are types of soil retaining structures that increase soil stability under static and dynamic loads. The damage caused by an earthquake can be determined by evaluating the probabilistic seismic response of SMSE walls. This study aimed to assess the seismic performance of SMSE walls and provide fragility curves for evaluating failure levels. The generated fragility curves can help to improve the seismic performance of these walls through assessing and controlling variables like backfill surface settlement, lateral deformation of facing, and permanent relocation of the wall. A parametric study was performed based on a non-linear elastoplastic constitutive model known as the hardening soil model with small-strain stiffness, HSsmall. The analyses were conducted using PLAXIS 2D, a Finite Element Method (FEM) program, under plane-strain conditions to study the effect of the number of geogrid layers and the axial stiffness of geogrids on the performance of SMSE walls. In this study, three areas of damage (minor, moderate, and severe) were observed and, in all cases, the wall has not completely entered the stage of destruction. For the base model (Model A), at the highest ground acceleration coefficient (1 g), in the moderate damage state, the fragility probability was 76%. These values were 62%, and 54%, respectively, by increasing the number of geogrids (Model B) and increasing the geogrid stiffness (Model C). Meanwhile, the fragility values were 99%, 98%, and 97%, respectively in the case of minor damage. Notably, the probability of complete destruction was zero percent in all models.

• Korean Journal of Heritage: History & Science
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• v.54 no.4
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• pp.4-21
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• 2021

The purpose of this study is to examine the names and types of walls constructed in the late Joseon Dynasty in YeonggeonUigwe, a record of construction works of the Joseon Dynasty, and to examine the current status and name of walls constructed in the main hall and the Yeongnyeongjeon Hall of Jongmyo Shrine. The results of the study are as follows. First, the name of the wall can be divided into four types depending on the characteristics, including direction, location, shape, function, material, and complexity, and was used as a compound word in front of the wall. Second, some of the wall types related to the material were found to have differences in the timing of theypes of walls. Since the 18th century, the use of earthen walls has been reduced, and the use of wooden walls and paper walls are often used. Third, the walls of the Jongmyo Shrine were composed of a mud wall and a fireproof wall. A fireproof wall was installed in the main hall, including a pillar, while the Yeongnyeongjeon Hall was installed only between the pillar and the pillar. Fourth, the Gap Wall can be defined as the "wall constructed at the upper part of the chamber used in the construction of the building in Jongmyo." This study is meaningful in that it attempted to clarify the definition of a wall in the late Joseon Dynasty by examining the names and examples of walls used in the late Joseon Dynasty, focusing on walls that lacked research in familiarity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.17-26
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• 2020

This study examined the structural effectiveness of the unbonded technique originally developed for seismic strengthening of unreinforced masonry walls on the basis of the prestressed steel bars and glass fiber (GF) grids. The masonry walls were strengthened by using individual steel bars or GF grids and their combination. Test results showed that the proposed technique was favorable in enhancing the strength, stiffness, and ductility of the masonry walls. When compared with the lateral load capacity, stiffness at the ascending branch of the lateral load-displacement curve, and energy dissipation capacity of the unstrengthened control wall, the increasing ratios were 110%, 120%, and 360%, respectively, for the walls strengthened with the individual GF grids, 140%, 130%, and 510%, respectively, for the walls strengthened with the individual steel bars, and 160%, 130%, and 840%, respectively, for the walls strengthened with the combination of steel bars and GF grids. The measured lateral load capacities of masonry walls strengthened with the developed technique were in relatively good agreement with the predictions by the equations proposed by Yang et al. Overall, the developed technique is quite promising in enhancing the seismic performance of unreinforced masonry walls.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.4
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• pp.171-187
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• 1991

In the present study, an analytical solution method is proposed for the seismic design of cantilever sheet pile walls and anchored sheet pile walls used in harbor construction. Seepage pressures, together with a change in magnitudes of effective horizontal soil pressures, are included in the proposed solution method. Also, the Mononobe-Okabe analysis as well as the Westergaard and Matsuo-Ohara theory of hydrodynamic pressures is used in the proposed method. Further, the choice of values for safety factors is examined for the seismic design of anchored sheet pile walls, and the effects of various parameters(dredge line slope, differential in water levels, anchor position, and wall friction angle) on embedment depth, anchor force, and maximum bending moment are analyzed for anchored walls in dense sand deposits. In addition. the tables that could be used for preliminary seismic design of anchored walls in dense sands are presented. The proposed method deals with the sheet pile walls with free earth support.

• Korean Journal of Microbiology
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• v.13 no.3
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• pp.109-115
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• 1975

DNA's were extracted from Saccharomyces cerevisiae and Mycobacterium phlei and the damaging cell walls of these microoragnisms were examined under an electron microscope in the extraction process in which a number of physico-chemical tratments of cells was involved. While the DNA was easily extracted from S. cerevisiae using conventional meylelded very little DNA, of M. phlei was extremely difficult to isolate and yielded very little DNA, applying various methods of isolation published earlier. When the cell walls of S. cerevisiae were examined with the electron microscope, they were not yet damaged even after the cells were treated with sodium lauryl sulfate(SLS) and ethylene diamine tetracetic acid(EDTA), but they were completely destroyed by the treatment of sodium perchlorate followed by the addition of chloroform and a vigorous agitation. Oozing cytoplasm through the broken cell walls was also observed. In the extraction of DNA from M.phlei, the pronase was not effective at the aerobic environment of the sample. When phenol was applied at the last step of DNA isolation, an extreme damage mass yielding little DNA into the solution. Unlike the cells of S.cerevisiae.M.phlei cells showed a tendency of aggregation, thus the destruction of cell walls by sodium hydroxide was seen only on the walls of peripheral cells in the aggregated mass, leaving the walls of the inner cells undamaged.

• Journal of the Korean Institute of Rural Architecture
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• v.19 no.3
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• pp.9-16
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• 2017

The study aims to find regional characteristics of Olle and Olle-Dam the old town of Jeju city, "Mu-geun-sung," through researches of the status of the spatial structure in the area. The research was mainly conducted through literature survey and field survey. Literature survey was conducted for the typification of alleys and stone walls. Field surveys were conducted to reveal the location, length, and materials of the stone walls on alleys. As a result, this study can grasp the spatial characteristics of the alleys and the typological characteristics of the stone walls in the old urban areas of Jeju City. The unit alley located in the old city area of Jeju was severely damaged. Also, the stone walls could reveal that there are few areas where the original shape is preserved. The management of the community has not been properly carried out in the use of alleys. In addition, there is concern about the damage caused by securing a road in the future. On the other hand, many of the damaged stone walls had basically the original shape. There were many stone walls that retained their original shape in the old alley. For this reason, there is a high possibility that the alleys and stone walls located in the old urban areas of Jeju are utilized as assets of the area. Based on the results of the above study, community recovery using old alleys of Jeju is required.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.1
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• pp.99-117
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• 2013

This study aims to suggest the values and utilization measures of the stone walls in Jeju Island as place assets. The discussion on this subject may serve as a breakthrough to resolve the current situation where the stone walls in Jeju Island have been focused on for their potential value not for their practical value as place assets. Moreover, specific measures to utilize Jeju stone walls may become a vehicle to seek the sustainable development of the region. This study discussed the types, functions and values of the stone walls in Jeju Island as place assets and suggested practical measures to use the structures based on their regional distribution. The in-depth discussions largely concluded that there might be five values and seven utilization measures with regard to the Jeju stone walls. The results of the study are expected to be utilized as a new indicator for the regional development of Jeju Island.

• Journal of the Korean Geotechnical Society
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• v.20 no.4
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• pp.65-74
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• 2004

Based on the field measuring data obtained from seven excavation sections in Inchon International Airport Project, the horizontal displacement of sheet piling walls supported by anchors and the lateral earth pressure acting on sheet piling walls was investigated in soft ground. The proposed diagram of lateral earth pressure is a rectangular form, and the maximum earth pressure corresponds to $0.6\gamma H$. The maximum earth pressure is similar to the empirical earth pressure proposed by NAVFAC(1982). The quantitative safe criterion of sheet piling walls with struts is established from the relationships between increasing velocity of maximum horizontal displacement and stability number in excavated ground. If the velocity of maximum horizontal displacement shows lower than 1mm per day, the sheet piling walls exist under stable state. When the velocity of maximum horizontal displacement becomes more than 1mm and less than 2mm per day, excavation works should be observed with caution. Also, when the velocity of maximum horizontal displacement becomes more than 2mm per day, appropriate remediations and reinforcements are applied to sheet piling walls.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.6
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• pp.205-214
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• 2010

Masonry structures have been used throughout the world for the construction of residential buildings. However, from a structural point of view, the masonry material is characterized by a very low tensile strength. Moreover, the bearing and shear capacity of masonry walls have been found to be vulnerable to earthquakes. In this study, to improve the seismic performance of masonry walls, hexagonal blocks were developed and six masonry walls made with hexagonal block were tested to failure under reversed cyclic lateral loading. This paper focuses on an experimental investigation of different types of wall with hexagonal blocks, i.e. walls with different hexagonal blocks and with different reinforcing bar arrangements, subjected to applied cyclic loads. The cracking, damage patterns and hysteretic feature were evaluated. Results from the hexagonal masonry wall were shown more damage reduction and less brittle failure in comparison to the existing rectangular masonry walls.

• Journal of the Korean Magnetics Society
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• v.13 no.4
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• pp.176-181
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• 2003

The magnetic domain walls at the edges of a large patterned and exchanged-biased NiO(10-60 nm)/NiFe(10 nm) bilayers and their motions with applied field were investigated by magnetic force microscopy. Three kinds of domain walls, namely, head-to-head zig-zag and tail-to-tail zig-zag Bloch walls and straight Neel walls were found at specific edges of the unidirectional biased NiO(30 nm)/NiFe(10 nm) bilayer having the exchange biasing field (H$\sub$ex/) of 21 Oe. No walls were observed for the strong exchange-biased bilayer (60 nm NiO, H$\sub$ex/ = 75 Oe), while the amplitude of the zig-zag domain increased with decreasing exchange biasing. This may be explained by mutual restraint between H$\sub$ex/ and the demagnetization field of edge. We similarly investigated the magnetization reversal process, the subsequent motion of the walls and identified the pinning and nucleation sites during reversal.