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        검색결과 113

        4.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to obtain basic data on domestic wild Lanopila nipponica K specimens collected in Jeollanam-do from 2015 to 2017 to investigate the characteristics of fruit bodies and analyze their nutritional components. L. nipponica K. was mainly found near hills, such as in persimmon fields around hills, on mountain trails, and in bamboo fields. L. nipponica K. occurred from July to mid-October, especially after the rainy season or a typhoon, when the air humidity was increased. Rainfall occurred for 8–15 days during the 20 days before the collection date, and the average temperature was ≥ 23oC. The size of the fruit body was 12.3–28 cm, and the weight varied depending on the size; however, the fruit body was estimated to grow overnight, reaching the size observed at its discovery. As aging progressed, the surface of the fruit body cracked, and it turned dark after 6 days. Spores were lump-shaped when the surface was cut with a knife. When the soil on the surface of the site where the fruit body was located was scratched, a white thread-shaped mycelium expanded. At the time of collection, the flesh of the fruit body was white, but it turned brown and fluffy as maturity progressed. On the sixth day after the mushroom was generated, it produced a pungent odor and became friable, resembling a black cotton ball. The surface of the fruit body was white and had a circular or elliptical shape. Crude protein content tended to be high at 59% of the dry weight. The antioxidant activity, determined using the DPPH radical scavenging analysis method, was 167 vitamin C equivalents/100 g. The spores were brown, approximately 6 μm in size, with protrusions on their surface.
        4,000원
        11.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, centrifuge model tests were performed to evaluate the seismic response of multi-DOF structures with shallow foundations. Also, elastic time history analysis on the fixed-base model was performed and compared with the experimental results. As a result of the centrifuge model test, earthquake amplification at the fundamental vibration frequency of the soil (= 2.44 Hz) affected the third vibration mode frequency (= 2.50 Hz) of the long-period structure and the first vibration mode (= 2.27 Hz) of the short-period structure. The shallow foundation lengthened the periods of the structures by 14-20% compared to the fixed base condition. The response spectrum of acceleration measured at the shallow foundation was smaller than that of free-field motion due to the foundation damping effect. The ultimate moment capacity of the soil-foundation system limited the dynamic responses of the multi-DOF structures. Therefore, the considerations on period lengthening, foundation damping, and ultimate moment capacity of the soil-foundation system might improve the seismic design of the multi-DOF building structures.
        4,000원
        12.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Gyeongju and Pohang earthquakes caused damages to many cultural properties; particularly, stone pagoda structures were significantly damaged among masonry cultural properties. To preserve these structures, it is necessary to understand their dynamic behavior characteristics under earthquakes. Analyses on such areas as deformation, frequency, maximum acceleration, permanent displacement, sliding, and rocking have to be performed. Although many analytical studies have already been conducted, dynamic behavior studies based on experiments are insufficient. Therefore, this study analyzed dynamic behavior characteristics by performing a shaking table experiment on a three-story stone pagoda structure at the Cheollongsa temple site damaged by the Gyeongju earthquake. As a result of the experiment, the displacements of stylobates did not occur significantly, but the tower body parts rotated. In particular, the rotation of the 1F main body stone was relatively larger than that of the other chief body stones because the 1F main body stone is relatively more slender than the other parts. In addition, the decorative top was identified as the component most vulnerable to sliding. This study found that the 1F main body stone is vulnerable to rocking, and the parts located on the upper part are more vulnerable to sliding.
        4,000원
        15.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In case of stone pagoda structures, the various construction types appear, and various damages occur due to exposure to the outdoors for a long time. Such damages can be classified into non-structural damages and structural damages. However, studies for the effects of structural damages on stone pagoda structures are insufficient. Accordingly, this study intends to perform structural modeling and structural analysis according to structural damages of stone pagoda structure, and to perform risk analysis through the fragility curve. So, we expects that this study gives a great contribution to the preservation and maintenance of stone pagoda structures under the various structural damages.
        4,000원
        16.
        2020.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study earthquake records were collected for rock conditions that do not reflect seismic amplification by soil from global earthquake databases such as PEER, USGS, and ESMD. The collected earthquake records were classified and analyzed based on the magnitude and distance of earthquakes. Based on the analyzed earthquakes, the design response spectrum shape, effective ground acceleration, and amplification ratios for each period band are presented. In addition, based on the analyzed data, the story shear force for 5F, 10F, 15F, and 20F were derived through an analysis of the elastic time history for multi-DOF structures. The results from analyzing the rock earthquake record show that the seismic load tends to be amplified greatly in the short period region, which is similar to results observed from the Gyeongju and Pohang earthquakes. In addition, the results of the multi-DOF structure analysis show that existing seismic design criteria can be underestimated and designed in the high-order mode of short- and medium-long cycle structures.
        4,000원
        17.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The stone pagoda continued to be damaged by weathering and corrosion over time, and natural disasters such as earthquake are accelerating the destruction of cultural properties. Stone pagoda has discontinuous structure behavior and is very vulnerable to the seismic load acting in lateral direction. It is necessary to analyze various design variables as the contact surface characteristics play an important role in the dynamic behavior of stone pagodas. For this purpose, contact surface characteristics of stone pagoda can be classified according to surface roughness and filler type, and representative model is selected and structural modeling and analysis are performed using the discrete element method. Also, the seismic load according to the repetition period is calculated and the dynamic analysis is performed considering the discontinuous characteristics of the stone pagoda. Finally, the seismic behavior characteristics can be analyzed by the evaluation of stresses, displacements and structural safety.
        4,000원
        18.
        2019.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To calculate proper seismic design load and seismic design category, the exact site class for construction site is required. At present, the average shear-wave velocity for multi-layer soil deposits is calculated by the sum of shear-wave velocities without considering of vertical relationship of the strata. In this study, the transfer function for the multi-layered soil deposits was reviewed on the basis of the wave propagation theory. Also, the transfer function was accurately verified by the finite element model and the eigenvalue analysis. Three methods for site period estimation were evaluated. The sum of shear-wave velocities underestimated the average shear-wave velocities of 526 strata with large deviations. The equation of Mexican code overestimated the average shear-wave velocities. The equation of Japanese code well estimated the average shear-wave velocities with small deviation.
        4,000원
        19.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ‘용아’는 목이버섯 국내 수집 자원인 JNM21008과 JNM21013의 단포자 교배를 통해 2014년 전남농업기술 원에서 육성한 품종이다. 2011년부터 2014년까지 자실체 특성 및 생산력 검정을 실시하였으며, 그 결과 2014년 갓 모양은 파도형으로 진한 흑갈색이며 연락맥은 갈회색을 띤 흑목이버섯을 최종 선발하였으며 2015년 품종보호출원, 2018년 품종보호등록하였다(제169호). ‘용아’의 재배적 특성과 수량성은 다음과 같다. 배양기간은 대조품종보다 더 빠르며 초발이 소요일수 또한 10일로 대조품종보다 5일 정도 빨랐다. 톱밥 봉지재배 시 자실체 특성으로 갓색은 대조품종보다 더 진한 흑갈색이었으며 유효경수는 13개/0.9 kg로 많았고 갓 장경 9.7 cm, 단경 5.6 cm로 갓 크기는 큰 경향이었다. 배양기간은 20℃에서 약 40일이며 발이 및 생육기간은 24일로 기존 품종보다 더 짧은 편이며 수량은 0.9 kg 봉당 291 g이었다. 교배모본과 대치선이 형성되었으며 모균주와 구별성을 보였다.
        4,000원
        20.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, comparative analysis of the 9.12 Gyeongju and 11.15 Pohang earthquakes was conducted in order to provide probable explanations and reasons for the damage observed in the 11.15 Pohang earthquake from both earthquake and structural engineering perspectives. The damage potentials like Arias intensity, effective peak ground acceleration, etc observed in the 11.15 Pohang earthquake were generally weaker than those of the 9.12 Gyeongju earthquake. However, in contrast to the high-frequency dominant nature of the 9.12 Gyeongju earthquake records, the spectral power of PHA2 record observed in the soft soil site was highly concentrated around 2Hz. The base shear around 2 Hz frequency was as high as 40% building weight. This frequency band is very close to the fundamental frequency of the piloti-type buildings severely damaged in the northern part of Pohang. Unfortunately, in addition to inherent vertical irregularity, most of the damaged piloti-type buildings had plan irregularity as well and were non-seismic. All these contributed to the fatal damage. Inelastic dynamic analysis indicated that PHA2 record demands system ductility capacity of 3.5 for a structure with a fundamental period of 0.5 sec and yield base shear strength of 10% building weight. The system ductility level of 3.5 seems very difficult to be achievable in non-seismic brittle piloti-type buildings. The soil profile of the PHA2 site was inversely estimated based on deconvolution technique and trial-error procedure with utilizing available records measured at several rock sites during the 11.15 Pohang earthquake. The soil profile estimated was very typical of soil class D, implying significant soil amplification in the 11.15 Pohang earthquake. The 11.15 Pohang earthquake gave us the expensive lesson that near-collapse damage to irregular and brittle buildings is highly possible when soil is soft and epicenter is close, although the earthquake magnitude is just minor to moderate (M 5+).
        4,000원
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