• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.973-987
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• 2018

Most of the previous seismic analyses have been carried out by separating the ground and structures, and there is a lack of comparative study on the dynamic behavior of high-rise and low-rise buildings. Therefore, in this study, the sensitivity analysis was performed with selected parameters by using a finite element analysis program in order to grasp the dynamic behavior of high-rise and low-rise buildings. As a result, it was turned out that the horizontal displacement, the interstory drift ratio, and the bending stress of a high-rise building were more affected by a long seismic wave than a low-rise buildings. Also, the weak parts of a high-rise and low-rise building were more affected by type of seismic wave than the ground conditions. Therefore, it is inferred that it will be helpful for seismic designs to consider the influence of ground conditions and seismic wave type on buildings.

• Korean Journal of Environmental Agriculture
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• v.38 no.2
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• pp.89-95
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• 2019

BACKGROUND: Liquid pig manure (LPM) has been used as an alternative for conventional fertilizers on some gramineous crops. However, its chemical properties varied widely depending on the degree of the digestion. A pot experiment was conducted to determine the responses of persimmon trees to immature (not well-digested) LPM application. METHODS AND RESULTS: Ten application levels of immature LPM, consisted of a total of 3 to 30 L in 3-L increment, were applied during summer to 5-year-old 'Fuyu' trees grown in 50-L pots. Increasing the LPM application rate caused defoliation, wilting, and chlorosis in leaves. When applied with the rate of 3 L during summer, the tree produced small fruits with low soluble solids and bore few flower buds the following season, indicating insufficient nutritional status. In trees applied with the LPM rates of 6~12 L, both fruit characteristics and above-ground growth of the trees appeared normal but some roots were injured. However, application of higher LPM rates than 27 L resulted in small size, poor coloration, or flesh softening of the fruits the current season. Furthermore, the high LPM rates caused severe cold injury in shoots during winter and weak shoot growth the following season. It was noted that the application of higher LPM rate than 9 L damaged the root, even though above-ground parts of the tree appeared to grow normally. CONCLUSION: The results indicated that an excessive immature LPM application could cause various injuries on leaves, fruits, and the roots in both the current and the following season.

• Earthquakes and Structures
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• v.17 no.2
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• pp.233-244
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• 2019

In this work, we have studied the effects of different soil thicknesses, haunch heights, reinforcement forms and construction technologies on the seismic performance of a composite precast fabricated utility tunnel by pseudo-static tests. Five concrete specimens were designed and fabricated for low-cycle reciprocating load tests. The hysteretic behavior of composite precast fabricated utility tunnel under simulated seismic waves and the strain law of steel bars were analyzed. Test results showed that composite precast fabricated utility tunnel met the requirements of current codes and had good anti-seismic performance. The use of a closed integral arrangement of steel bars inside utility tunnel structure as well as diagonal reinforcement bars at its haunches improved the integrity of the whole structure and increased the bearing capacity of the structure by about 1.5%. Increasing the thickness of covering soil within a certain range was beneficial to the earthquake resistance of the structure, and the energy consumption was increased by 10%. Increasing haunch height within a certain range increased the bearing capacity of the structure by up to about 19% and energy consumption by up to 30%. The specimen with the lowest haunch height showed strong structural deformation with ductility coefficient of 4.93. It was found that the interfaces of haunches, post-casting self-compacting concrete, and prefabricated parts were the weak points of utility tunnel structures. Combining the failure phenomena of test structures with their related codes, we proposed improvement measures for construction technology, which could provide a reference for the construction and design of practical projects.

• Wind and Structures
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• v.28 no.5
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• pp.299-313
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• 2019

In order to examine the effects of different wind deflectors on the wind load distribution characteristics of extra-large cooling towers, a comparative study of the distribution characteristics of wind pressures on the surface of three large cooling towers with typical wind deflectors and one tower without wind deflector was conducted using wind tunnel tests. These characteristics include aerodynamic parameters such as mean wind pressures, fluctuating wind pressures, peak factors, correlation coefficients, extreme wind pressures, drag coefficients and vorticity distribution. Then distribution regularities of different wind deflectors on global and local wind pressure of extra-large cooling towers was extracted, and finally the fitting formula of extreme wind pressure of the cooling towers with different wind deflectors was provided. The results showed that the large eddy simulation (LES) method used in this article could be used to accurately simulate wind loads of such extra-large cooling towers. The three typical wind deflectors could effectively reduce the average wind pressure of the negative pressure extreme regions in the central part of the tower, and were also effective in reducing the root of the variance of the fluctuating wind pressure in the upper-middle part of the windward side of the tower, with the curved air deflector showing particularly. All the different wind deflectors effectively reduced the wind pressure extremes of the middle and lower regions of the windward side of the tower and of the negative pressure extremes region, with the best effect occurring in the curved wind deflector. After the wind deflectors were installed the drag coefficient values of each layer of the middle and lower parts of the tower were significantly higher than that without wind deflector, but the effect on the drag coefficients of layers above the throat was weak. The peak factors for the windward side, the side and leeward side of the extra-large cooling towers with different wind deflectors were set as 3.29, 3.41 and 3.50, respectively.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.353-362
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• 2022

Recently, transmittance of photomasks for ultra-violet (UV) region is getting more important, as the light source wavelength of an exposure process is shortened due to the demand for technologies about high integration and miniaturization of devices. Meanwhile, such problems can occur as damages or the reduction of yield of photomask as electrostatic damage (ESD) occurs in the weak parts due to the accumulation of static electricity and the electric charge on chromium metal layers which are light shielding layers, caused by the repeated contacts and the peeling off between the photomask and the substrate during the exposure process. Accordingly, there have been studies to improve transmittance and antistatic performance through various functional coatings on the photomask surface. In the present study, we manufactured antireflection films of Nb₂O₅, | SiO₂ structure and antistatic films of ITO designed on 100 × 100 × 3 mmt sodalime glass by DC magnetron sputtering system so that photomask can maintain high transmittance at I-line (365 nm). ITO thin film deposited using In/Sn (10 wt.%) on sodalime glass was optimized to be 10 nm-thick, 3.0 × 103 𝛺/☐ sheet resistance, and about 80% transmittance, which was relatively low transmittance because of the absorption properties of ITO thin film. High average transmittance of 91.45% was obtained from a double side antireflection and antistatic thin films structure of Nb₂O₅ 64 nm | SiO₂ 41 nm | sodalime glass | ITO 10 nm | Nb₂O₅ 64 nm | SiO₂ 41 nm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.3
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• pp.371-377
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• 2020

Currently used iris cameras are expensive and have many limitations in their use. Existing iris cameras are inconvenient in interworking with newly developed software, and light reflections generated during iris photography are inadequate for medical use. Therefore, it is impossible to utilize the existing camera to take an image by yourself. In this paper, the iris camera is newly constructed so that the iris can be photographed by ourselves and the area of interest can be seen well. Anyone can easily wear glasses-type iris cameras to acquire images using IoT devices, and the acquired images are linked to the iris analysis program and used to read genetic weak parts. The proposed iris camera module automatically provides light reflection, shake, and accurate focus when capturing images, increasing the accuracy of image analysis to 91.49%. In addition, we have proved through experiments that one image processing time is fast as 0.007ms due to accurate image input.

• English & American cultural studies
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• v.14 no.2
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• pp.311-336
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• 2014

The essay examines two different editions of Anne Askew's Examinations published in the sixteenth century: John Bale's the First Examination and the Latter Examination and John Foxe's Acts and Monuments, and argues that retelling and rewriting one's experience is the process of storytelling that necessitates the repetition and communication of the experience. The essay looks at the parts the sixteenth-century editors particularly rewrote or retold the original version, and discusses how Askew's story was retold, repeated, and communicated through various storytellers who delivered not only the original text but also the original experience toward larger audience. While attempting to interpret, analyze, and expand on the story she did not tell, or the story she could not tell, Bale and Foxe developed her personal and anecdotal story into a communal narrative to share. Bale wrote a weak woman's martyrology by adding his interpretation and analysis, showing the way for the readers to follow in understanding her enigmatic silence and gestures. On the other hand, Foxe made the story a more dramatic and more seamlessly flowing narrative of the heroic sacrifice of a martyr. Foxe filled the room left by Askew's silence with directly quoted conversations and the graphic that could help explain what was between the lines. Apart from the rewritings of the reformists, the essay focuses on the fact that the editing, rearranging, and reinterpreting process already started with Askew's own writing. Although Askew declares herself an objective recorder of the series of events, her writing is carefully constructed with complex ideological fractures and rhetorical tactics, and her experience is tailored to fit a particular purpose. Along with Bale's and Foxe's rewritings, Askew's story of a reading woman should be also read as an intentional and interpretative storytelling on her own experience.

• Composites Research
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• v.35 no.3
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• pp.196-200
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• 2022

Split Hopkinson Pressure Bar (SHPB) is a general test equipment for measuring the mechanical properties of high modulus metal and composite materials at high strain rate. However, for the soft plastic material, it is difficult to hold the specimen and achieve dynamic stress equilibrium due to the weak transmitted signals. In this study, SHPB test apparatus were designed to measure accurately the high strain rate stress-strain curve of the soft plastic materials by changing the incident bar materials and the shape of the specimen holder parts. In addition, to verify the high strain-rate tensile strain data obtained from SHPB, the strain distribution of the specimen was measured and analyzed with a high-speed camera and the digital image correlation (DIC), which was compared with the strain history measured from SHPB.

• Journal of People, Plants, and Environment
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• v.23 no.4
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• pp.423-432
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• 2020

Background and objective: Traditional farming is winning recognition as a sustainable alternative farming method. As urban farming increases in South Korea, it is crucial to develop more sustainable farming techniques. Gyeonjongbeop is the traditional farming method introduced in the Joseon period. This study was conducted to propose a productive garden model suitable for urban farming through the interpretation of traditional farming methods contained in Imwongyeongjeji Bolliji and to test the model on an actual field. Methods: Using the design and cropping system of Gyeonjongbeop as the research materials, we reviewed its tillage and cultivation and examined the applicability. We proposed a modified method by extracting parts applicable to urban farming. According to the methods, we created a garden with ridges and furrows, cultivated proper vegetables, and evaluated their growth. Results: Raphanus sativus, Allium fistulosum L., Brassica juncea, and Spinacia oleracea grown on ridges showed higher growth than those grown on a conventional flat field. The growth of Hordeum vulgare var. hexastichon and Triticum aestivum L. on furrows was also slightly higher. This proved that the method could make up for the deficiencies of barley and wheat that are weak against winds and cold and are easily destroyed by the spring rains. Conclusion: Ridge and furrow cultivation derived from Gyeonjongbeop can be an efficient urban farming system compared to the conventional cultivation in flat fields. The system can use fallow lands in winter for year-round urban farming. In addition, the application of the traditional farming system can enhance the humanistic value of urban farming.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.421-431
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• 2023

Recently, the destructive power of typhoons is continuously increasing due to the influence of global warming. In a situation where the installation of floating wind turbines is increasing around the world, concerns about the huge loss and collapse of floating offshore wind turbines due to strong typhoons are deepening. Regarding to the safe operation of the floating offshore wind turbine, the development of a new type of disconnectable mooring system is required. A new fairlead chain stopper considered in this study is devised to more easily attach or detach the floating offshore wind turbine with mooring lines comparing to other disconnectable mooring apparatuses. In order to investigate the structural safety of the initial design of fairlead chain stopper that can be applied to MW-class floating type offshore wind turbine, scale-down structural models were produced using a 3-D printer and structural tests were performed on the models. For the structural tests of the scale-down models, tensile specimens of acrylonitrile butadiene styrene material that was used in the 3-D printing were prepared, and the material properties were evaluated by performing the tensile tests. The finite element analysis of fairlead chain stopper was performed by applying the material properties obtained from the tensile tests and the same load and boundary conditions as in the scale-down model structural tests. Through the finite element analysis, the structural weak parts on the fairlead chain stopper were reviewed. The structural model tests were performed considering the main load conditions of fairlead chain stopper, and the test results were compared to the finite element analysis. Through the results of this study, it was possible to experimentally verify the structural safety of the initial design of fairlead chain stopper. It is also judged that the study results can be usefully used to improve the structural strength of fairlead chain stopper in a detailed design stage.