• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.259-266
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• 2012

A general earthquake resistant design philosophy of ductile frame buildings allows beams to form plastic hinges adjacent to beam-column connections. In order to carry out this design philosophy, the ultimate bond or shear strength of the beam should be greater than the flexural yielding force and should not degrade before reaching its required ductility. The behavior of RC members dominated by bond or shear action reveals a dramatic reduction of energy dissipation in the hysteretic response due to the severe pinching effects. In this study, a method was proposed to predict the deformability of reinforced concrete members with short-span-to-depth-ratios, which would result in bond failure after flexural yielding. Repeated or cyclic loading produces a progressive deterioration of bond that may lead to failure at lower cyclic bond stress levels. Accumulation of bond damage is caused by the propagation of micro-cracks and progressive crushing of concrete in front of the lugs. The proposed method takes into account bond deterioration due to the degradation of concrete in the post yield range. In order to verify bond deformability of the proposed method, the predicted results were compared with the experimental results of RC members reported in the technical literature. Comparisons between the observed and calculated bond deformability of the tested RC members showed reasonably good agreement.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.3 s.49
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• pp.47-55
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• 2006

Seismic performance and retrofit of reinforced concrete (RC) two-column piers widely used at roadway bridges in Korea was experimentally evaluated. Ten two-column piers that were 400 mm in diameter and 2,000 mm in height were constructed. These piers were subjected to hi-directional cyclic loadings under a constant axial load of $0.1f_{ck}A_g$. Test parameters were the confinement steel ratio, loading pattern, lap splice of longitudinal reinforcing bars, and retrofitting method. Specimens with lap-spliced longitudinal bars were retrofitted with steel jacket, pre-stressing steel wire, and steel band. Test result showed that while the specimens subjected to bi-directional lateral cyclic loadings which consisted of two main amplitudes in the transverse axis and two sub amplitudes in longitudinal axis, referred to as a T-series cyclic loadings, exhibited plastic hinges both at the top and bottom parts of the column, the specimens subjected to bi-directional lateral cyclic loadings in an opposite way, referred to as a L-series cyclic loadings, exhibited a plastic hinge only at the bottom of the column. The displacement ductility of the specimen under the T-series loadings was bigger than that of the specimen under the L-series loadings. Specimen retrofitted with pre-stressing steel wires exhibited poor ductility due to the upward shift of the plastic hinge region because of over-reinforcement, but specimens retrofitted with steel jacket and steel band showed the required displacement ductility. Steel band can be an effective retrofitting scheme to improve the seimsic performance of RC bridge piers, considering its practical construction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.6
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• pp.12-18
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• 2021

The purpose of this study is to effectively mitigate the bending displacement that occurs in the bridge due to forced vibration. We developed CTMD (Combine Tuned Mass Damper) that combines the relationship between spring and mass to control the bending behavior of simple beams. The experiment was conducted to confirm the control effect according to the change in the mass ratio of the developed CTMD. The developed CTMD is designed and manufactured so that the mass ratio can be adjusted according to the characteristics of the bridge. The maximum load of the spring applied to CTMD was fixed at 33.15 N. In order to evaluate the performance of the developed CTMD, a simple beam composed of hinges and rollers as boundary conditions was fabricated. In the experimental method, a CTMD was installed in the center of a simple beam and the deflection displacement according to the mass ratio was measured. The shaking condition was shaken at 3 Hz to induce the maximum bending behavior of the simple beam. As a result of the experiment, it was confirmed that when the optimal mass ratio was 2.1, the damping rate of the bending behavior displacement was about 71.2 %, indicating the best control effect.

• 기호학연구
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• no.56
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• pp.137-158
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• 2018

In 1999, the French semiotician Jacques Fontanille published his work on discourse semiotics as an attempt to overcome the limitations of structuralism. Discourse semiotics has expanded the realm of semiotics by taking a phenomenological approach that examines the structure of consciousness. Phenomenology pays special attention to the operation of human consciousness, which, instead of staying put, moves from one place to another-unbeknownst to its agent. This paper examines "Bulls" through a phenomenological approach as the short story depicts the stream of consciousness that unfolds within the inner world of Pau, the young male protagonist. The rhetorical approach to literary analysis works at the level of the speech act and directly relates to speech act theory. In rhetorics, figures and tropes are dominated by speech acts. Whereas conventional rhetorical analysis lacks a kinetic perspective as it revolves around flat semantic inspections, the discourse semiotics approach applied in this paper allows for an indepth multidimensional analysis where the analyses of ${\acute{e}}nonc{\acute{e}}$ and ${\acute{e}}nonciation$ complement each other. Presenting a peasant movement to the reader through the eyes of the young male protagonist Pau, "Bulls" is considered a significant literary feat in the history of Korea's New Literature as the work is highly regarded for its impressive depiction of a communal movement. This paper reinterprets and reevaluates the story under a new light, mainly through a rhetorical approach and a phenomenological approach that hinges on discourse semiotics.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.6
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• pp.371-383
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• 2021

Steel-concrete single-leaf blast-resistant doors, having steel box and slab inside, are installed on the wall using supporting members such as hinges and latches. Several studies have been conducted on their deflection behavior in the same direction as that of the blast pressure, but studies on their deflection behavior in the opposite direction, that is, studies on negative deflection behavior are relatively insufficient. In this study, we conducted a parameter analysis using finite element analysis on blast-resistant doors, on their rebound behavior in the negative deflection phase. Results revealed that the plastic deformation of the door, and the change in momentum and kinetic energy during rebound, were major factors influencing the rebound behavior. Greater rebound force was developed on the supporting members in the impulsive region, than in the quasi-static region; due to the characteristics in the impulsive region, where the kinetic energy developed relatively greater than the strain energy. In the design process, it is necessary to consider excessive deformation that could occur in the supporting members as the rebound behavior progresses. Additionally, it was found that in the case of steel-concrete blast doors, the rebound force increased relatively more, when the effects of both rebound and negative blast pressure contributed to the negative deflection of the door. Since conditions for the occurrence of this superposition effect could vary depending on structural characteristics and explosion conditions, further investigation may be required on this topic.

• Journal of the Korean Chemical Society
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• v.37 no.2
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• pp.237-243
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• 1993

The primary and secondary structure of the 5S rRNA isolated from Xanthomonas celebensis were determined by enzymatic and chemical degradation methods. It consists of 119 nucleotides and contains no modified nucleosides. As with the 5S rRNAs of X. maltophilia and X. citri, it contains an additional uridine residue on the 5'-terminus. Its secondary structure was almost identical to the models previously proposed by us for the 5S rRNA of two Xanthomonas species. Its secondary structure consists of five helices, five loops and two bulges. The tertiary interactions in the 5S rRNA molecule were analyzed by Fe(II)-EDTA treatment and hybridization method using deoxyhexamer. From the fact that some adenine residues in loop M, region $I_1-C$, loop $H_1$, and loop $H_2$ become susceptible to diethylpyrocarbonate when the 5S rRNA was hybridized with deoxyhexamer complementary to the sequence $U_{35}CCCAU_{40}$ and that some nucleotide residues in loop M, loop $H_1$ and region $D-I_2$ become resistant Fe(II)-EDTA cleavage in the presence of $Mg^{2+}$, it is presumed that loops $H_1$ and $H_2$ interact with loop M in some way. In the tertiary interaction, the regions $I_1-C$ and $D-I_2$ seem to act as hinges in folding the stems $B-I_1-C$ and $D-I_2-E.$ It was found that loop $H_1$ changes into a smaller loop of three bases by forming noncanonical A : C base-pairs ih acidic environment.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.541-554
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• 2019

The Taebaeksan Zone of the Okcheon Belt is a prominent fold-thrust belt, preserving evidence for overlapped polyphase and diachronous orogenic events during crustal evolution of the Korean Peninsula. The Pyeongchang-Jeongseon area of the northwestern Taebaeksan Zone is fault-bounded on the western Jucheon and southern Yeongwol areas, showing lateral variations in stratigraphy and structural geometries. For better understanding these geological characteristics of the northwestern Taebaeksan Zone, we have studied the structural geometry of the Pyeongchang-Jeongseon area. For this, we have firstly carried out the SHRIMP U-Pb age analysis of the age-unknown sedimentary rock to clarify stratigraphy for structural interpretation. The results show the late Carboniferous to middle Permian dates, indicating that it is correlated to the Upper Paleozoic Pyeongan Supergroup. In addition to this, we interpreted the geometric relationships between structural elements from the detailed field investigation of the study area. The major structure of the northwestern Taebaeksan Zone is the regional-scale Jeongseon Great syncline, having NE-trending hinge with second-order folds such as the Jidongri and Imhari anticlines and the Nambyeongsan syncline. Based on the stereographic and down-plunge projections of the structureal elements, the structural geometry of the Jeongseon Great syncline can be interpreted as a synformal culmination, plunging slightly to the south at its southern area, and north at the northern area. The different map patterns of the northern and southern parts of the study area should be resulted in different erosion levels caused by the plunging hinges. Considering the Jeongseon Great syncline is the major structure that constrains the distribution of the Paleozoic strata of the Pyeongchang and Jeongseon areas, the symmetric repetition of the lower Paleozoic Joseon Supergroup in both limbs should be re-examined by structural mapping of the Hangmae and Hoedongri formations in the Pyeongchang and Jeongseon areas.

• Journal of Bio-Environment Control
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• v.11 no.1
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• pp.5-11
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• 2002

In this study, new development of natural ventilation window was accomplished to control environment of greenhouse with no use of farced ventilation during hot season. The ventilation effect of developed ventilation window was investigated in experimental greenhouse which was designed using side wall panel and folding type panel fur natural ventilation. Folding panel type ventilation window was designed to open upper part of the side wall and top of the roof using two hinges which are located bottom of the side wall and the roof panel to grab one side of each panels and guide the other side along with the guidance rail. Developed ventilation window has top ventilation part with maximum moving distance X=ι (1-cos$\theta$)=848.5 mm and side ventilation part with maximum moving distance Y=ι/2 $\times$sin$\theta$=1,184.4 mm at 45$^{\circ}$ of theoretical opening angle. It took 4.5 minutes to open roof vent fully and temperature at 1.2 and 0.8 m height decreased after 1 minute from starting opening and became equilibrium state maintaining 3-4$^{\circ}C$ difference after 2 minutes from complete opening. Air exchange rate was 15.2~39.3 h$^{-1}$ which was more than 10~15 h$^{-1}$ of continuous type and Venlo type greenhouse. The descent effect of temperature by ventilation windows was two times higher than Venlo type greenhouse.

• Fashion & Textile Research Journal
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• v.24 no.6
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• pp.667-685
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• 2022

This paper aims to investigate 4D printing materials for soft robots. 4D printing is a targeted evolution of the 3D printed structure in shape, property, and functionality. It is capable of self-assembly, multi-functionality, and self-repair. In addition, it is time-dependent, printer-independent, and predictable. The shape-shifting behaviors considered in 4D printing include folding, bending, twisting, linear or nonlinear expansion/contraction, surface curling, and generating surface topographical features. The shapes can shift from 1D to 1D, 1D to 2D, 2D to 2D, 1D to 3D, 2D to 3D, and 3D to 3D. In the 4D printing auxetic structure, the kinetiX is a cellular-based material design composed of rigid plates and elastic hinges. In pneumatic auxetics based on the kirigami structure, an inverse optimization method for designing and fabricating morphs three-dimensional shapes out of patterns laid out flat. When 4D printing material is molded into a deformable 3D structure, it can be applied to the exoskeleton material of soft robots such as upper and lower limbs, fingers, hands, toes, and feet. Research on 4D printing materials for soft robots is essential in developing smart clothing for healthcare in the textile and fashion industry.