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        검색결과 933

        181.
        2018.05 구독 인증기관·개인회원 무료
        In this study, several approaches in evaluating moisture sensitivity of asphalt mixtures were investigated and compared. To evaluate the moisture damage resistance, twenty types of asphalt mixtures with and without anti stripping additives were tested in the laboratory. Uniaxial compressive strength (UCS) and indirect tensile (IDT) testing were performed to determine the Tensile Strength Ratio (TSR) and Cohesion Strength Ratio (CSR). Stone Mastic Asphalt (SMA) mixtures were found to provide good moisture damage resistance compared to other mixtures. It also does not require anti stripping additives to improve its moisture resistance. Moreover, the correlation coefficient between the TSR test and CSR tests is 0.99 with an average error of 1.5%, which indicates that the TSR test following AASHTO T-283 is still the most reasonable criteria in evaluating the moisture damage of AC mixtures. Marshall Stability Ratio (MSR) and Marshall Stability to Flow Ratio (MSFR) were conducted and were compared to TSR test results. It was found that MSFR value may be used to evaluate the moisture damage resistance of AC mixtures instead of TSR test. Finally, Dynamic Immersion (DI) test was performed to evaluate moisture resistance for loose asphalt mixtures. The DI results showed good correlation also when evaluating moisture resistance compared to TSR. When using DI testing in evaluating moisture resistance, it is recommended to test after 48 hours since it showed higher correlation with the TSR values. Further study is recommended to improve current testing evaluating moisture susceptibility of asphalt mixtures to properly associate it with TSR values.
        182.
        2018.05 구독 인증기관·개인회원 무료
        다양한 활용용수 생산을 위한 막 소재 및 막여과 공정개발이 고도화됨에 따라 점차적으로 유지관리 측면의 연구개발 필요성이 부각되고 있다. 그 중에서 유지관리 측면의 막 손상 검지와 수명예측은 제도적으로 정립이 미흡한 실정이며, 막여과 공정 운영에서 경제성과 안정성을 고려한 막 손상 검지 기술개발은 막 특성 및 시설규모에 따른 오차보상이 불가피하게 수반되어야 하는 연구이다. 따라서 분리막의 물리/화학적 노출강도에 따른 특성 변화를 관찰하여 내구년한 산정 및 수명예측 알고리즘을 구축하고자 한다. 또한 분리막의 특성과 모듈의 배열에 따라 최적화된 막 손상 검지를 위한 기체-액체 치환율을 기반으로 물리적 한계도출과 병행하여 이를 극복하기 위한 센싱융합 기술을 소개하고자 한다.
        183.
        2018.05 구독 인증기관·개인회원 무료
        In the present study, the impact of RO polyamide layer by long-term chemical exposure was evaluated. Basic cleaning chemicals such as NaOH increased the pure water flux and salt passage of RO membrane up to 1.6 times and 2 times, respectively. In contrast, membranes exposed to acidic chemicals such as HCl have experienced no discernible change of permeability, which indicated that basic chemicals caused the more serious damage to RO polymeric layers. However, XPS analysis showed that both membranes were experienced significant damages on cross-linking of polyamide structures. It can be concluded that basic cleaning chemicals induced the enlarged pore structure due to electrostatic repulsion between damaged polymers, while acidic chemicals caused less performance deterioration by shrinkage of the polyamide structure.
        185.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Wikstroemia ganpi grow the southern coastal regions in Korea, small population and are classified as a critically endangered species. The majority of habitats are located near forest paths and reservoirs at the edge of mountains, indicating that there is considerable human interference and severe fragmentation of populations, as well as damage to individuals as a result of forest fires and soil erosion. We evaluated the genetic diversity in populations, genetic differentiation between populations, and genetic structure to provide data to support the conservation of W. ganpi. W. ganpi populations showed lower genetic diversity(mean level: P.95=36%, S.I=0.170, h=0.113) and higher genetic differentiation(40%) between populations than other species with similar characteristics did. And the among population gene flow(Nm) was highly restricted at 0.87. The four populations revealed that there were fixed alleles in the different loci of each population. This result can be explained by the effects of genetic drift. Structure analysis and the PCA results were more indicative of separate groups than a genetic structure that was linked to populations. This reflects the high level of genetic differentiation between populations and the unique alleles within each population. As a result, lower genetic diversity and higher genetic differentiation between populations of W. ganpi. And the effects of inbreeding were observed, as well as asexual reproduction in some populations. Therefore, to conserve W. ganpi, all the surveyed populations need to be designated for on-site conservation and monitored continually. A research on the spatial genetic structure needs to be conducted to obtain information on sample extraction for off-site conservation. This structure would be able to minimize the wasting of samples that could be obtained from limited genetic resources and would enable further focused and efficient management.
        4,300원
        186.
        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
        187.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 국내 멧돼지 문제는 농작물 피해 및 도심 출몰로 인하여 사회적으로 심각한 상황에 직면해 있다. 본 연구는 경남 거창군의 멧돼지에 의한 농작물 피해사례를 바탕으로 피해에 영향을 끼치는 환경 요인들에 대하여 파악하고자 2012년 5월부터 10월까지 수행 되었다. 농작물 피해 분석 결과 주로 8월과 9월 사이 피해가 가장 많이 발생하였고, 벼의 빈도가 가장 높았으며 피해 강도는 고구마가 가장 높은 것으로 나타났다. 이는 멧돼지의 농작물 선호성과 특정시기에 대한 가용성과 관련이 있는 것으로 판단된다. 또한 농작물 피해에 경사, 지형기복, 산림과의 거리, 수계로부터의 거리, 도로로부터의 거리, 주거지로부터의 거리의 요인들이 영향을 미치는 것으로 나타났다. 피해 강도에 따른 환경요인의 차이는 나타지 않아 멧돼지는 한번 피해를 끼친 농경지를 지속적으로 방문하여 피해를 누적 시키는 것으로 파악된다. 따라서 멧돼지에 의한 농작물 피해를 저감시키기 위해서는 피해가 발생할 수 있는 곳에 멧돼지가 비선호하는 작물로 대체 재배하며 전기펜스 설치, 엽사와 포획틀을 이용한 멧돼지 개체수 조절이 필요할 것으로 판단된다.
        4,000원
        188.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Severe earthquakes can cause damage to society both socially and economically. An appropriate initial response can alleviate damage from severe earthquakes. In order to formulate an appropriate initial response, it is necessary to identify damage situations in societies; however, it is difficult to grasp this information immediately after an earthquake event. In this study, an earthquake damage assessment methodology for buildings is proposed for estimating damage situations immediately after severe earthquakes. A response spectrum database is constructed to provide response spectra at arbitrary locations from earthquake measurements immediately after the event. The fragility curves are used to estimate the damage of the buildings. Earthquake damage assessment is performed from the response spectrum database at the building scale to provide enhanced damage condition information. Earthquake damage assessment for Gyeongju city and Pohang city were conducted using the proposed methodology, when an earthquake occurred on September 12, 2016, and November 15, 2017. Results confirm that the proposed earthquake damage assessment effectively represented the earthquake damage situation in the city to decide on an appropriate initial response by providing detailed information at the building scale.
        4,000원
        189.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study examines the seismic failure of RC low-rise building structures having irregularities at the ground story during the 15 November 2017 Pohang, Korea, earthquake, Mw = 5.4, which is the second strongest since the government began monitoring them in 1978 in South Korea. Some 2,000 private houses were damaged or destroyed in this earthquake. Particularly, serious damage to the piloti story of RC low-rise residential building structures of fewer than five stories was observed within 3 km of the epicenter with brittle shear failure of columns and walls due to severe torsional behavior. Buildings below six stories constructed before 2005 did not have to comply with seismic design requirements, so confinement detailing of columns and walls also led to inadequate performance. However, some buildings constructed after 2005 were damaged at the flexible side of the piloti story due to the high torsional irregularity. Based on these results, this study focuses on the problems of the seismic torsion design approach in current building codes.
        4,000원
        190.
        2018.04 구독 인증기관 무료, 개인회원 유료
        In this study, to develop the basis of damage prediction system for abutment type rigid-frame bridge, measurement data is generated by artificially expressing damage by Abaqus, a commercial structural analysis program, and applied to machine-learning. The rigid-rame bridge structural analysis model is expressed as closely as possible to the actual bridge condition considering the specification, damage expression, analysis method, boundary condition, and load. CNN(Convolutional Neural Network), one of the neural network algorithm, is used for machine-learning and accuracy is confirmed when there was no measurement error as a result of machine learning.
        3,000원
        191.
        2018.04 구독 인증기관·개인회원 무료
        The mulberry for production of mulberry fruit, found the damage and quantity according to the level of damage by the A. mori, and through regression analysis, we set up a economic injury level. The level of damage by A. mori was to be artificially adjusted, for 2 percent, 5%, 8 percent, and 11 percent of leaf damage. Investigate, From May 31 to June 14, they compared the damage to each damage level and the growth and development and quantity. The survey found that the more damage level, the more severe the damage. The ratio of damage fruit was 5.1 percent, 11 percent, 13.2 percent, 23.9 percent, respectively. And the quantity was reduced by about 33% from 11 percent to 2,387 g/tree compared to the 2 percent to 3,557 g/tree. There's no difference in the damage caused by the sclerotium disease, and the growth and development, such as the length of the tree, the length of the branches, and the thickness of branches. The relationship between the damage level and the ratio of damage fruit was able to obtain relations with the linear regression, Y = 2.129552 X +0.569663(R2 = 0.98). It's the result of an analysis, which analyzed the damage level's relationship with the ratio of damage fruit have a high correlation rate. Therefore, It’s about the ratio of the quantity losses is 5 percent, the ratio of damage leaf is 2.08 percent. If the ratio of damage leaf is more than 2.08 percent, the damage will be required the control. It is judged.
        192.
        2018.04 구독 인증기관·개인회원 무료
        우리나라는 약 4,000여개의 크고 작은 섬들로 이루어져 있고, 그 속에는 다양한 생물종들이 주변 환경과 상호작용하 며 서식하고 있다. 그 중 초식성 곤충은 생물 구성의 1/4로 많은 비율을 차지하며, 생산자인 식물을 먹고 2차 소비자의 먹이원이 됨으로써 생태계의 중간 고리 역할을 한다. 본 연구는 다도해해상국립공원에 속해 있는 크기가 다른 6개의 섬에서 초식성 곤충의 영향을 알 수 있는 식흔과 여기에 영향을 줄 수 있는 환경요인(섬 면적, 육지와의 거리, 해안선 길이, 최고고도)과의 관계를 알아보았다. 식흔을 알아보기 위해 낙엽활엽수인 4개의 수종(참나무속, 벚나무속, 예덕나무속, 오리나무속)을 선정하여 2017년 6월과 9월에 관찰하였다. 이와 함께 초식성 곤충 중 종 다양성이 풍부한 나방을 채집하여 식흔자료와 비교하였다. 조사결과 섬 면적이 커질수록, 해안선의 길이가 길수록, 최고고도가 높을수록 식흔량이 증가하는 경향을 보였고, 나방의 종수도 증가하였다. 반면 육지와의 거리가 멀수록 식흔량이 감소하는 경향을 보였고, 나방 종수도 감소하였다. 이러한 결과를 통해 초식성 곤충의 다양성과 환경요인이 관련 있는 것을 확인할 수 있었다
        193.
        2018.04 구독 인증기관·개인회원 무료
        Aphelenchoides composticola is an economic pest in mushroom cultivation, with a potential to cause heavy losses in the commercial production of Agaricus spp. Recently, A. composticola was intercepted on cultivated mushrooms in Korea and herein, this newly recorded species is morphologically and morphometrically characterized, and symptoms of mushroom damage are equally illustrated. The offset head, a prominent muscular median bulb, oval to round in shape, lateral field with three incisures, tapering truncate tail and average body length of 612.8μm, characterize females. Males are slightly smaller (561.2μm), characterized by well-developed paired spicules, ventrally curved tail, and conoid tail terminus posed with a terminal mucro.
        194.
        2018.04 구독 인증기관·개인회원 무료
        Heterodera trifolii, mostly known as clover cyst nematode, is currently a serious problem for Chinese cabbage growers of the highland area in Korea. Due to lack of readily information about the nematode on Chinese cabbage in Korea, the pest steadily spread within the highland areas and has become a serious setback. Occurrence, spatial aggregation, egg hatching and the pathogenicity of this nematode are depicted in this study from ecological point of view. The study results suggest site-specific control and a potential planting time for the cabbage to avoid severe damage caused by this nematode.
        195.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 신경퇴행성질환과 밀접한 관련이 있는 neurofilament-L(NF-L)의 산화적 손상에 엄나무 발효물이 미치는 영향을 알아보고자 하였다. 용액 상에서 peroxyl radical을 생성하는 AAPH를 처리하여 NFL의 산화적 변형을 유도하고 엄나무 추출물(KP), 노루궁뎅이버섯 균사체 추출물(HE), 엄나무 발효물(KP-HE)을 각각 처리하여 어떤 영향을 미치는 지를 알아보고자 하였다. KP와 HE는 peroxyl radical에 의한 NF-L의 산화적 손상을 막지 못했으나 KP-HE는 NF-L의 변형을 효과적으로 억제하였다. KP-HE는 peroxyl radical에 의한 NF-L 변형에서 나타나는 dityrosine 형성을 효과적으로 억제하였고 peroxyl radical 소거활성도 증가시켰다. 파킨슨병 환자에서 발견되는 신경독성물질인 tetrahydropapaveroline(THP)에 의한 NFL의 변형에 KP, HE, KP-HE가 미치는 영향을 관찰하였다. 그 결과 KP-HE는 KP와 HE에 비해서 THP에 의한 NF-L의 변형을 효과적으로 억제하는 것으로 관찰되었다. 또한 KP-HE는 THP에 의한 NF-L 변형에서 나타나는 dityrosine 형성도 효과적으로 억제하였고 THP에 의해 유도되는 활성산소 생성도 현저히 감소시켰다. 이와 같은 결과들은 KP-HE가 활성산소와 신경독성물질에 의한 산화적 스트레스로부터 세포를 보호해 줄 수 있을 것으로 사료되었다. 그러므로 엄나무 발효물은 신경퇴행성질환을 예방할 수 있는 식품소재로 이용될 수 있을 것으로 사료된다.
        4,200원
        196.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        2008년부터 시작된 국제유가의 급락으로 인한 국내 에너지기업들은 재정부 담이 가중되어 다양한 자원공급 포트폴리오를 구성하여 사업을 정상적으로 추진하는데 많은 어려움을 겪고 있다. 특히 해양에너지자원의 개발은 육상자원에 비하여 탐사, 시추, 생산단계에 소요되는 기간이 길고, 이에 수반되는 위험들이 많기 때문에 BP, Exxon, Chevron 등과 같은 국제석유회사들과 같이 다양한 측면에서 자원개발에 따른 위험을 분산 관리하는 기술과 체계가 필요하다. 그러나 국내 에너지기업들은 해양에너지 자원개발의 필요성과 중요성을 인식하고 있음에도 불구하고, 여전히 하류부분(Downstream) 위주의 산업구조를 형성하여 전형적인 자원빈국으로서의 한계에 직면해 있다. 따라서 국내 에너지기업들 은 상류부분(Upstream) 및 중류부분(Midstream) 단계로 사업영역을 확대하는데 단계별로 발생할 수 있는 다양한 위험을 최적화된 보험을 통하여 관리할 수 있는 역량이 부족하여 주도적으로 프로젝트를 운영하지 못하고 있다. 따라서 이 연구는 Operators, Duty Holder(Tier1), Integrated EPC Services(Tier2) 및 하도 급 OEM/Specialist providers(Tier3)로 연계된 해양에너지와 관련된 전 생애주기에 국내 조선해양플랜트기업 및 선박관리회사들이 단순히 인력 공급만 할 것이 아니라 새로운 형태의 부가가치를 창출할 수 있는 종합적인 서비스를 제공하는 데 필수적인 안정장치인 해양에너지 종합보험 중물적 손해의 위험관리와 관련된 약관에 대해서 보험이론, 국내외 판례 등을 중심으로 법적 검토를 진행하고, 2015 영국보험법 개정에 따른 사항 및 주요 적용범위의 명확화 등을 중심으로 개선방안을 제시하였다.
        8,700원
        197.
        2018.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        호두는 경제적으로 중요한 유실수 중 하나이지만, 호두나무 포장 내에서 해충에 의한 피해 특성에 대한 정보는 매우 부족하다. 본 연구에서 는 복숭아명나방과 굴피가는나방에 의한 호두열매와 잎의 피해를 조사하였다. 2017년 충남 부여군에 위치한 포장에서 복숭아명나방에 의한 호두열매 피해율의 변화를 조사하였다. 또한 김천, 부여, 영동 및 화성의 포장 내에서 2종의 나방에 의한 호두열매 및 잎의 피해율을 조사하였다. 부여 포장 내 호두열매의 피해율은 시간이 흐름에 따라 지속적으로 증가하였고, 피해율은 늦여름에 가장 높았다. 호두열매의 최종 피해율은 부여, 김천 및 화성에서 각각 22.1%, 20.5%, 11.7%로 조사되었다. 굴피가는나방에 의한 잎 피해는 성목의 신초 가지(평균 11.2%)에 비해 묘목의 신초 가지(평균 58.5%)에서 더 높은 것으로 조사되었다. 본 연구 결과, 호두나무 포장 내에서 복숭아명나방과 굴피가는나방에 의한 열매와 잎 피해가 심각한 것으로 확인되었으며, 향후 이들에 대한 방제기술 개발이 필요할 것으로 판단된다.
        4,000원
        198.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 4주간의 동계훈련기간 중 산수유 추출물을 섭취시켜 간 기능, 근 손상 및 혈중 피로물질에 미치는 영향을 구명하기 위하여 남중 축구선수 20명을 대상으로 동계훈련+산수유 추출물 섭취군(10 명), 동계훈련군(10명)으로 구분하여 실시하였다. 동계훈련은 1일 오전, 오후, 야간운동으로 구분하여 주 6 일, 4주간 실시되었으며, 운동강도는 70-95%HRR로 수행되었다. 산수유 추출물은 매일 아침과 저녁 식사 후 각각 80 mL(1일 160mL)를 4주간 섭취시켰으며, 측정된 자료의 그룹 내 변화는 대응표본 T검정, 그룹 간 차이는 변화율을 산출 한 뒤 독립표본 T검정을 이용하여 비교 분석하였다. 그 결과 혈중 피로물질의 젖산은 동계훈련+산수유 추출물 섭취군에서 유의하게 감소하였으며(p<.05), 동계훈련군 보다 동계훈련+산수유 추출물 섭취군이 유의하게 감소하였다(p<.05). 암모니아는 동계훈련+산수유 추출물 섭취군(p<.05), 동계훈련군(p<.001) 모두 유의하게 증가하였다. 근 손상지표의 CK는 동계훈련+산수유 추출물 섭취군이 유의하게 감소하였으며(p<.05), LDH는 동계훈련+산수유 추출물 섭취군(p<.001), 동계훈련군(p<.05) 모두 유의하게 감소하였다. 간 기능 효소 중 AST(p<.01), ALT(p<.05)는 동계훈련+산수유 추출물 섭취군이 유의하게 감소하였으며, AST는 동계훈련군 보다 동계훈련+산수유 추출물 섭취군이 유의하게 감소하였다. 동계 훈련 시 피로에 쉽게 노출 될 수 있는 선수들에게 있어 산수유 추출물 섭취는 항피로의 역할을 하는데 긍정적인 영향을 미치는 것으로 사료된다.
        4,300원
        199.
        2017.12 구독 인증기관 무료, 개인회원 유료
        This study was conducted to understand damage effects of Roe Deer (Capreolus capreolus) on the seedlings of Evergreen Oak (Quercus acuta) with the cutting of main stems before planted at Jeju Experimental Forests. Six plots in size of 20 × 20 m had been setup from the middle to the end of March, 2007, and planting after cutting the main stems of seedlings had been conducted to increase survival rate of the seedlings, and we monitored experimental and control plots to know the damage effects of the deers. Experimental plots were designed at the width of 3 m fields after clear-cutting, and they was adjacent with the buffer zone in size of 2 m covered with vegetation covers. Seedlings were planted at interval of 1 x 1 m, they were at 8 rows and 20 lines per plot. Two rows among them had been treated as half cutting at main stems. Total 647 seedlings had been planted, 168 seedlings were belong to half cutting's plots and 479 were to control plots. As a result, half cutting did not increase the survival rate of seedlings, and it increases the ratio of deer damage. Damaged seedlings showed significantly the lower height than undamaged did. Therefore, it would indicate that planting the seedlings over 90 cm in height would decrease the damage from deer at study areas. And, we suggest the damage factors on Quercus acuta as apical bud grazing, bark rubbing, and leaf grazing, we made the flow chart to decide the damage factors in the field.
        4,000원
        200.
        2017.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the seismic performance of concrete-steel composite moment frame structures equipped with seismic retrofitting systems such as seismic reinforcement, base isolators, and bracing members, which are typical earthquake damage mitigation systems, is evaluated through nonlinear dynamic analyses. A total of five frame models were designed and each frame model was developed for numerical analyses. A total of 80 ground acceleration data were used to perform the nonlinear dynamic analysis to measure ground shear force and roof displacement, and to evaluate the behavioral performance of each frame model by measuring inter-story drift ratios. The analysis results indicate that the retrofitting device of the base isolator make a significant contribution to generating relatively larger absolute displacement than other devices due to flexibility provided to interface between ground and column base. However, the occurrence of the inter-story drift ratio, which is a relative displacement that can detect the damage of the structure, is relatively small compared with other models. On the other hand, the seismic reinforced frame model enhanced with the steel plate at the lower part of the column was found to be the least efficient.
        4,300원