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        검색결과 2,415

        1.
        2024.04 구독 인증기관·개인회원 무료
        해상특수교량은 특수한 환경적 조건뿐 아니라 고주탑의 구조형식, 보호재로 쌓여있는 케이블 등 특 수한 형식을 가지고 있어 일반적인 육안전검으로 안전점검을 할 수 없는 사각지대가 존재한다. 주탑의 외부 손상상태 및 케이블의 손상에 대해서는 정밀안전점검에서도 점검이 되지 않는 경우가 대부분이 므로 이에 대한 대책 마련이 시급하다. 또한 해상특수교량에 대한 전문적인 경험과 기술이 부족한 관 리자도 대상교량의 손상과 이상거동을 직관적으로 확인하고 판단할 수 있는 지원체계가 필요하다. 이 에 본 연구에서는 해상특수교량 고주탑에 대한 손상정보를 파악하기 위하여 드론의 자동비행 기술을 개발하고 이를 이용하여 주탑 외부 균열 손상에 대한 안전점검을 실시하고 이를 분석하였다.
        2.
        2024.04 구독 인증기관·개인회원 무료
        최근 지방정부는 지역경제 활성화를 위한 관광객 유치를 위해 다양한 모양 구조를 가지는 출렁다리 를 경쟁적으로 건설하고 있다. 이러한 출렁다리의 안전관리는 자체 가이드라인이나 국토교통부에서 발 간한 매뉴얼을 통해 관리되고 있으나 실제로는 관광이나 공원 관리 부서에서 관리하고 있어 안전관리 에 소홀한 실정이다. 국토교통부에서는 제3종시설물에 대한 안전점검 매뉴얼 발간하고 안전등급 평가 기준을 강화하여 기존 3분위(양호, 보통, 불량) 평가기준을 5분위(우수, 양호, 보통, 미흡, 불량) 평가체 계로 개정하였으며, 기존 세부지침과 평가기준도 일원화 하였다. 그러나 출렁다리의 경우 제1종, 제2 종 시설물인 교량과 달리 점검 방식 및 체크리스트가 달라져야 하므로 출렁다리 정기안전점검을 위한 점검 수준에 맞게 개선되어야 한다. 본 연구에서는 출렁다리에 안전전검에 체계 개선을 위한 출렁다리 정기안전점검 매뉴얼(안)을 제시하였다.
        3.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 글은 볼테르의 󰡔캉디드󰡕에서 ‘낙관주의’라는 이름을 통해 냉소적으로 풍자된 라이프니츠의 철학을 재검토하는 것을 목적으로 한다. 볼테르의 낙관주의에 대한 문제의식은 특히, 우리가 살아가는 이 세계가 가능한 최선의 세계 또는 최선의 가능 세계라는 정식에 집중되어 있다. 그러나 라이프니츠의 󰡔변신론󰡕에서 나타나는 이 정식에 대한 오해는 볼테르가 신의 지적, 논리적 선택을 인간의 윤리에 영향을 주는 선악의 문제로 곧장 등치한 결과이다. 라이프니츠에게 있어서 세계는 단순히 우리를 둘러싼 외부 환경만을 의미하지 않고, 모든 인간 개체들 스스로도 각자 하나의 세계라고 할 수 있다. 그리고 신의 지적인 선택과 결정은 가능한 모든 상황, 관계를 아우르는 법칙에 관한 것이기에 신은 우리의 고통에 자의적으로 개입하지 않는다. 신이 직접 개입해서 자연 재해, 전쟁 등 세계에 존재하는 부조리를 해결해 주기를 바라는 것은 인간적인 기대일 뿐이다. 󰡔변신론󰡕에서 신에 의해 허용된 악의 본질은 결핍이며, 라이프니츠의 처방은 그러한 결핍으로부터 벗어나려는 노력으로 제시된다. 최선의 논리는 이 세계가 윤리적 악과 고통에도 불구하고 가장 좋은 것이라는 방관적인 윤리적 귀결과는 거리가 멀다.
        6,900원
        4.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the event of an emergency such as facility shutdown during process operation, the by-product gas must be urgently discharged to the vent stack to prevent leakage, fire, and explosion. At this time, the explosion drop value of the released by-product gas is calculated using ISO 10156 formula, which is 27.7 vol%. Therefore, it does not correspond to flammable gas because it is less than 13% of the explosion drop value, which is the standard for flammable gas defined by the Occupational Safety and Health Act, and since the explosion drop value is high, it can be seen that the risk of fire explosion is low even if it is discharged urgently with the vent stock. As a result of calculating the range of explosion hazard sites for hydrogen gas discharged to the Bent Stack according to KS C IEC 60079-10-1, 23 meters were calculated. Since hydrogen is lighter than air, electromechanical devices should not be installed within 23 meters of the upper portion of the Bent Stack, and if it is not possible, an explosion-proof electromechanical device suitable for type 1 of dangerous place should be installed. In addition, the height of the stack should be at least 5 meters so that the diffusion of by-product gas is facilitated in case of emergency discharge, and it should be installed so that there are no obstacles around it.
        4,000원
        5.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study is to evaluate the possibility of damage to cultural assets resulting from vibrations generated by construction vehicle traffic. The cultural heritage's natural vibration frequency was determined to be 150Hz by measurement. The damping ratios were calculated as 4.7% using the logarithmic decrement approach and 4.3% using the half-power method. The vibration measurements obtained during vehicle operation indicated that, despite an increase in vehicle velocity of up to 15 km/h, the vibrations remained below the detectable level of 0.13 mm/sec. When the road is curved and the terrain is sloped, a suitable speed for vehicle operation was found to be around 17 km/h, at which point vibrations were seen. The highest recorded vibration amplitude at this velocity was 0.217 mm/sec, which remains below the stringent regulation limit of 2 mm/sec. Thus, it can be concluded that there is no actual harm caused by vibrations.
        4,000원
        6.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Given the recent increases in feed cost, the demand for rice straw has been increasing on dairy farms because it is cheaper than expensive imported forages. Therefore, it is necessary to study the effect of rice straw feeding on the growth and productivity of dairy heifers. This study compared how feeding tall fescue and rice straw affects the growth, age at first calving, and feed cost of heifers. we compared the growth, age at first calving, and feed cost for each group during the breeding period. Body height was higher in the tall fescue-fed group than in the rice straw-fed group (p<0.05). The length of the growing stage was significantly shorter in the tall fescue group than in the rice straw group (p<0.001) and the age at calving also showed a significant reduction in the tall fescue group compared to the rice straw group (p<0.001). However, the feed cost was lower in the rice straw group because of the difference in the unit price of forage (p<0.001). Based on these results, during the growing period, the rice straw group had delays in growth and the age at first calving compared to the tall fescue group, but also had reduced feed costs in the short term.
        4,000원
        7.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        After the United Nations Convention on the Law of the Sea (UNCLOS) and the United Nations Fish Stocks Agreement (UNFSA) came into effect, international cooperation through Regional Fisheries Management Organizations (RFMOs) was required, and each RFMO established and adopted the Conservation and Management Measure (CMM) for the regional Observer Programs to collect data on fishing activities and biological information and to monitor compliance with its CMMs. The observer coverage required by RFMO is set differently for each organization, ranging from 5% to 100%. In addition, tuna-RFMOs recommend increasing observer coverage in longline fisheries by at least 20% for reliable quantitative analysis of not only target species but also bycatch species and ecologically related species such as sharks, seabirds, sea turtles, and marine mammals. Therefore, in this study, we discussed ways to improve the national observer programs of Korean distant water fisheries that should be addressed in the future to respond to the RFMO trends.
        4,000원
        8.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To understand the spatiotemporal distribution pattern of zooplankton and the environmental factors influencing zooplankton abundance in Gomso Bay, major harvesting area of Manila clam (Venerupis philippinarum) in South Korea, zooplankton sampling was conducted four times in autumn (October 2022), winter (January 2023), early spring (March 2023), and spring (May 2023). Among the environmental factors of Gomso Bay, water temperature, chlorophyll a concentration (Chl-a), dissolved oxygen (DO), and pH observed different patterns, while salinity and suspended particulate matter (SPM) showed no significant statistical differences between the survey periods. The zooplankton in Gomso Bay occurred 33, 29, 27, and 29 taxonomic groups during each respective survey period. In October 2022 and May 2023, arthropod plankton were dominated, while in January and March 2023, protozoa were primarily dominant. Among the Arthropods, copepods including Acartia hongi, Paracalanus parvus s. l., Corycaeus spp., and Oithona spp. commonly found along Korean coastal areas of the Yellow Sea, were dominated. Cluster analysis based on zooplankton abundance indicated a single community (stable condition) in each season, attributed to low dissimilarity distances, while three distinct clusters (autumn, winter-early spring, spring) between seasons indicated a highly seasonal environment in Gomso Bay.
        4,800원
        9.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Milky white spots appeared on red bean leaves in a red bean cultivation area located in Jangyeon-myeon, Goesan-gun, Chungbuk Province. After culturing the pathogen in PDA medium, their morphology was observed, and their genes were BLAST-searched in the National Center for Biotechnology Information (NCBI). The pathogen was identified as a fungus called Rhizopus arrhizus. As a result of reinoculating the isolated pathogen on red beans, the same symptoms as those in the isolated leaves occurred. Characteristic colonies of R. arrhizuson PDA medium initially showed a bright color and then changed to dark gray over time, with mostly spherical sporangia. The sporangiospores were spherical or elliptical, mostly irregular, and small in size. Therefore, based on these results, this disease has not yet been reported in red beans and was called red bean brown leaf blight caused by Rhizopus arrhizus A. Fisch (syn. R. oryzae).
        4,000원
        10.
        2023.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        AA1050/AA6061/AA1050 layered sheet was fabricated by cold roll-bonding process and subsequently T4 and T6 aging-treated. Two commercial AA1050 sheets of 1 mm thickness and one AA6061 sheet of 2 mm thickness were stacked up so that an AA6061 sheet was located between two AA1050 sheets. After surface treatments such as degreasing and wire brushing, they were then roll-bonded to a thickness of 2 mm by cold rolling. The roll-bonded Al sheets were then processed by natural aging (T4) and artificial aging (T6) treatments. The as roll-bonded Al sheets showed a typical deformation structure, where the grains are elongated in the rolling direction. However, after the T4 and T6 aging treatments, the Al sheets had a recrystallized structure consisting of coarse grains in both the AA5052 and AA6061 regions with different grain sizes in each. In addition, the sheets showed an inhomogeneous hardness distribution in the thickness direction, with higher hardness in AA6061 than in AA1050 after the T4 and T6 age treatments. The tensile strength of the T6-treated specimen was higher than that of the T4-treated one. However, the strength-ductility balance was much better in the T4-treated specimen than the T6-treated one. The tensile properties of the Al sheets fabricated in the present study were compared with those in a previous study.
        4,000원
        11.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The occurrence of eggs and adults of Pochazia shantungensis, Lycorma delicatula, and Lymantria dispar was investigated in 11 cities in the Chungcheongbukdo region. The results showed that the overwintering eggs of P. shantungensis occurred in 24.2% of the region in 2021 and 22.1% in 2022, while adults occurred in 25.2% in 2021 and 24.3% in 2022, indicating the highest occurrence among the pests studied. The occurrence of overwintering eggs of L. delicatula was relatively low, with 2.6% of the region affected in 2021 and 1.9% in 2022. Adult L. delicatula occurred in 3.2% of the region in 2021 and 3.6% in 2022. Overwintering eggs of L. dispar occurred in 4.1% of the area in 2021 and 1.7% in 2022, showing a decreasing tendency compared to the previous year, and their occurrence was only low to middle in terms of the degree of occurrence. Adult L. dispar occurred in 4.6% of the region in 2021 and 2.7% in 2022, showing occurrences that were insignificant compared to L. delicatula. According to a survey of host preferences, both the wintering eggs and adults of P. shantungensis were found in apples and peaches between 2021 and 2022. In both 2021-2022, adult L. delicatula had a high incidence in peaches, apples, and grapes, and winter eggs were the highest in grapes. However, the incidence in apples and peaches was low. A high incidence density of L. dispar moth adults and overwintering eggs was found in apples in both 2021 and 2022.
        4,200원
        12.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Herbicide-resistant transgenic rapeseed (TG rapeseed) was developed by inserting phosphinothricin acetyltransferase (PAT, bar), a modified gene from the soil bacterium Streptomyces hygroscopicus, into the genome of a conventional variety of rapeseed (Youngsan). The TG rapeseed used for the test was confirmed to express the PAT gene by polymerase chain reaction (PCR) and immunostrip. Feeding tests were conducted with Cyprinus carpio to evaluate the environmental risk of TG rapeseed, including the herbicide resistant gene. C. carpio was fed 100% ground rape suspension, TG rapeseed, or non-genetically modified (GM) counterpart rapeseed (Youngsan). As a result, the feeding test showed no significant differences in the cumulative immobility or abnormal response between C. carpio samples fed on TG rapeseed and non-GM counterpart rapeseed. The 48 h-LC50 values of the TG rapeseed and the non-GM counterpart rapeseed were 3,376 mg/L (95 % confidence limits: 3,169 - 3,596 mg/L) and 2,682 mg/L (95 % confidence limits: 2,267 – 3,123 mg/L), respectively. The rape NOEC (no observed effect concentration) value for C. carpio was suggested to be 625 mg/L. Based on these results, there was no significant difference in the toxicity for non-target organisms (C. carpio) between the TG rapeseed and non- GM counterparts.
        4,000원
        13.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate immune changes by comparing the proportion and function of immune cells in the blood under high-temperature period and convalescence temperature period in Holstein dairy cows. The experiment was conducted using Holstein dairy cows of five animals per group (60 ± 20 months old, 175 ± 78 non-day) from the National Institute of Animal Science at high-temperature period (THI: 76 ± 1.2) and convalescence temperature period (THI: 66 ± 1.3). Complete blood count results showed no change in the number of immune cells between groups. In the analysis using Flow Cytometry of PBMCs, no significant differences were observed among B cells, Helper T cells, cytotoxic T cells, and γδ T cells between groups. However, there was an increase in Th17 cells producing IL-17a, while Th1 cells decreased during the convalescence temperature period. The results of gene expression analysis using qRT-PCR in PBMCs revealed an increase in IL-10 during the convalescence temperature period, while a decrease in HSP70 and HSP90 was observed. In conclusion, the increased expression of IL-10 and the decrease in HSP expression suggest the possibility of a weak recovery from heat stress. However, the lack of observed changes in B cells, T cells, and other immune cells indicates incomplete recovery from heat stress during the convalescence temperature period.
        4,000원
        14.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon black is a material in the form of fine black powder obtained by incomplete combustion or pyrolysis of hydrocarbons, and is composed of 90-99% carbon, and the rest is composed of hydrogen and oxygen. In the event of an emergency during the manufacture of carbon black, the generated tail gas should be safely discharged through an emergency line to prevent fire, explosion, and environmental pollution accidents caused by the tail gas. If the pressure continues to rise, the pressure control valve shall operate and the rupture plate shall be ruptured sequentially and the tail gas shall be discharged to the vent stack through the emergency line. As an emergency emission system, even if some untreated substances in the tail gas are released into the atmosphere, they are lighter than air, so it is safe to discharge them to a safe place through the Vent Stack. If the gas pressure is rising or worse, it is discharged from the Vent Stackine, and discharging fuel.
        4,000원
        15.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we detected the presence of residual pesticides in 341 agricultural products collected from local food outlets in western Gyeonggi Province. Residual pesticides were detected in 105 (30.8%) samples. Six samples exceeded the legal limits for residual pesticides, resulting in a non-compliance rate of 1.8%, which was slightly higher than the average non-compliance rate of 1.4% in the last three years. Among the tested agricultural products, only fruits and vegetables were found to have pesticide residues, with 24 of 34 fruits (a detection rate of 70.6%) and 81 of 277 vegetables (a detection rate of 29.2%) testing positive. In total, 59 types of pesticides, including acetamiprid, which was detected 208 times, were detected and had a detection range of 0.01–2.38 mg/kg. Among the 105 agricultural products containing pesticide residues, a single pesticide was detected in 62 samples (59%) and two or more pesticides were detected in 43 samples (41%). In particular, 14 pesticides were detected in the same sample of peaches; dinotefuran was detected 21 times. Upon examining the toxicity of the detected pesticides, Class III pesticides (moderate toxicity) were detected 44 times (21.2%) and Class IV pesticides (low toxicity) were detected 164 times (78.8%). Class I, II, and III pesticides with fish toxicity were detected 68 (32.7%), 14 (6.7%), and 126 times (60.6%), respectively. Upon examining the exposure to high-frequency pesticide components detected five or more times, the hazard index was found to be ≤2.8%. Accordingly, the hazard of residual pesticides based on dietary intake was deemed insignificant.
        4,000원
        17.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the structural performance of the specimen fabricated through 3D printing was evaluated through monotonic loading experiments analysis to apply to 3D printed structures. The compression and flexural experiments were carried out, and the experimental results were compared to the finite element model results. The loading directions of specimens were investigated to consider the capacity of specimens with different curing periods, such as 7 and 28 days. As a result, the strength tended to increase slightly depending on the stacking direction. Also, between the 3D-printed panel composite and the non-reinforced panel, the bending performance depended on the presence or absence of composite reinforcement.
        4,000원
        18.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper proposes a standardized vehicle body repair manual for vehicles with major damage to the rear side members caused by rear-end collisions. The manual is used to refine the vehicles. Typical work involves replacing large traffic accident modes with new members or modifying and aligning existing members. If repairs are made for various reasons, the members should be attached based on the body of a new vehicle. Unlike new vehicle members, the accident vehicle repair process depends heavily on the operator's skilled skills (i.e., the performance, purpose, level, and quality of the body replacement work due to the nature of the vehicle body replacement work). When repairing or replacing a rear side member of a body repair, three methods of operation are applied because the damage and deformation vary depending on the object of the other party, although the degree of damage varies. There is no standardized manual for side member over-hole replacement, partial replacement, or partial modification, since these repair methods vary depending on the operator's thoughts and angle of view. Therefore, customers should use standardized vehicle repair manuals to ensure that their vehicle receives the same repair when damaged. This study is expected to develop a standardized vehicle repair manual to reduce the drop in used market prices after replacement or repair of rear side members at vehicle repair plants.
        4,000원
        19.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        양산시 동면 금산리 일원의 공사현장 사면 3개 지점에서 미고결 퇴적층을 절단하는 단층이 확인되었으며, 노두 단면에서 관찰되는 단층의 상세 구조분석을 수행하였다. 이곳 금산리 지점은 기존에 제4기 단층운동이 보고된 가산단층 지점으로부터 북쪽으로 약 0 .6 k m 떨어진 곳에 위치한다. 관찰된 총 6조의 단층들은 14o-32oE 주향을 가지고 3조의 단 층들은 77o-87oNW, 나머지 3조의 단층들은 53o-62oSE로 경사진다. 단층에 의해 절단된 미고결 퇴적층은 동편의 금정산 에서 유래된 선상지 역암으로 주로 화강암 또는 화산암 기원의 직경 0.5m 이상의 거력으로 구성된다. 단층면 상에 발 달하는 단층조선은 역이동성 성분이 포함된 우수향 주향이동단층 운동감각을 지시하며, 이러한 변형특성은 한반도 현생 응력환경인 동북동-서남서 압축응력과 부합한다. 사면에서 관찰되는 기반암과 미고결 퇴적층과의 부정합면을 기준으로 산정한 단층의 겉보기 수직변위는 동편이 15 m, 서편이 1 m이다.
        4,200원
        20.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
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