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        검색결과 5,647

        121.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study investigated the effects of forage cutting and baler mixing on the chemical compositions, fermentation indices, and aerobic stability of whole crop rice (WCR) haylage. The WCR (“Youngwoo”) was harvested at 48.4% dry matter and ensiled into a 300 kg bale silo with forage cutting (whole crop without cutting vs. 5 cm of cutting length). The WCR forages were ensiled without baler mixing process (CON) or with (MIX). The concentrations of dry matter, crude protein, ether extract, crude ash, neutral detergent fiber, and acid detergent fiber of whole crop rice before ensiling were 48.4, 9.70, 2.57, 6.11, 41.2, and 23.5%, respectively. The forage cutting did not affect the chemical compositions, fermentation indices, microbes, and aerobic stability of WCR haylage (p>0.05). The CON haylages tend to be higher in NDF content (p<0.10). The MIX haylages had lower in lactate (p=0.019), and lactate:acetate ratio (p<0.001). The MIX haylages had higher in lactic acid bacteria (LAB) (p=0.010). Therefore, this study concluded that the fermentation quality of WCR haylage improved by baler mixing, but had no effects by forage cutting.
        4,000원
        124.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was carried out to examine double cropping system using Italian ryegrass (IRG) 'Kowinearly', whole crop rice 'Yeongwoo' and barnyard millet 'Jeju native' during the Oct. 2020 to Oct. 2022. Three kinds of forage crops were cultivated at paddy field in Livestock Institute, Jeollanamdo Agricultural Research and Extension Services, Jeollanamdo, South Korea. Whole crop rice (WCR) was sown in late May and barnyard millet (BM) sown early June each year after harvesting IRG. We examined dry matter yield and feed value of forage crops depending on harvest time of forage crops during the experimental period. The plant height in heading stage of IRG ranged from 108 to 112cm and dry matter yield ranged from 6,783 to 11,530 kg ha-1. The crude protein (CP) of IRG ranged from 6.0 to 8.44%, acid detergent fiber (ADF) ranged from 55.6 to 60.2% and neutral detergent fiber (NDF) ranged from 32.58 to 36.7%, The dry matter yield of WCR increased as the harvest stage was delayed (14,310 kg ha-1 in milk, 16,167 kg ha-1 in yellow ripen, and 18,891 kg ha-1 in mature). Similar to results of dry matter yield of WCR, dry matter yield of BM increased as the harvest stage was delayed (11,194 kg ha-1 in late heading. and 14,308 kg ha-1 in mature), However nutrient content of WCR and BM showed a decreasing trend. As shown in above results, the productivity of WCR after harvesting IRG was shown to be high at paddy field in the southern region. However, BM also was appeared to have potential as summer forage crops.
        4,000원
        125.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This experiment was carried out to determine effects of seed rate of native grasses, called native summer forage crops (NSFC), on their growth characteristics and yields in no-tillage paddy fields in central provinces. NSFC cultivation was performed according to the agricultural guidelines of the Rural Development Administration (RDA) during 2020 to 2022. Echinochloa crusgalli ‘Jeju native’, Setaria viridis ‘Korean native type’, Digitaria sanguinalis ‘Korean native type’) were sown by various seed rate in the experimental field (3m × 4m plot) of Department of Animal Resources Development, Seonghwan–eup, Cheonan, Korea in late-May or early-June for 3 years and harvested in middle-September. Dry matter yields (DMY) in Echinochloa crusgalli and Setaria viridis increased as increasing seed rate. DMY in 40 kg ha-1 of Echinochloa crusgalli was the highest and DMY in 60 kg ha-1 of Setaria viridis was the highest. However, All treatments of Digitaria sanguinalis showed similar DMY. Yields of NSFC were the order of Echinochloa crusgalli (9,681~11,092 kg ha-1) > Digitaria sanguinalis (8,311~9,023 kg ha-1) >etaria viridis (3,145~4,749 kg ha-1). The contents of crude protein in NSFC were the order of Digitaria sanguinalis > Echinochloa crusgalli > Setaria viridis. The contents of ADF and NDF in NSFC were the order of Echinochloa crusgalli > Digitaria sanguinalis > Setaria viridis. As shown in above results, we suggest that introduction of NSFC is one of the most important skills in order to stably increase yields of forage crops for utilization of the double cropping system in no-tillage paddy fields.
        4,000원
        126.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study sought to conduct a fundamental investigation in order to test and evaluate the thermal performance of an aluminum stick curtain wall system. In terms of the thermal performance index, the infiltration rate of air tightness, thermal transmittance of the heat insulation property and temperature difference ratio of condensation resistance were experimentally measured. The research process can be divided into three parts. First of all, a database for the test report of the curtain wall was compiled and existing design criteria with respect to the evaluation method and standard of transparent building components such as curtain wall, window and door were analyzed to produce the specimens. Secondly, four different types of curtain wall specimens were created through investigating the curtain wall database. Thirdly, standard tests of thermal performance were carried out for airtightness, thermal performance and condensation resistance. As a result, the curtain wall specimens with low-e triple glazing covered by an aluminum capture system showed high thermal performance compared to other curtain wall specimens including low-e triple glazing with a 4-sided structural sealant glazing system. Air tightness of all types of curtain wall specimens satisfied level 1 standard for air tightness. It was found that a curtain wall which consists of a one track frame has difficulties meeting the residential standard of thermal performance with regard to thermal transmittance and condensation resistance.
        4,300원
        127.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Forest destruction is an inevitable result of the development processes. According to the environmental impact assessment, over 10% of the destroyed trees need to be recycled and transplanted to minimize the impact of forest destruction. However, the rate of successful transplantation is low, leading to a high rate of tree death. This is attributable to a lack of consideration for environmental factors when choosing a temporary site for transplantation and inadequate management. To monitor transplanted trees, a field survey is essential; however, the spatio-temporal aspect is limited. This study evaluated the applicability of remote sensing for the effective monitoring of transplanted trees. Vegetation indices based on satellite remote sensing were derived to detect time-series changes in the status of the transplanted trees at three temporary transplantation sites. The mortality rate and vitality of transplanted trees before and after the transplant have a similar tendency to the changes in the vegetation indicators. The findings of this study showed that vegetation indices increased after transplantation of trees and decreased as the death rate increased and vitality decreased over time. This study presents a method for assessing newly transplanted trees using satellite images. The approach of utilizing satellite photos and the vegetation index is expected to detect changes in trees that have been transplanted across the country and help to manage tree transplantation for the environmental impact assessment.
        4,500원
        128.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to estimate the damage of Whole Crop Corn (WCC; Zea Mays L.) according to abnormal climate using machine learning as the Representative Concentration Pathway (RCP) 4.5 and present the damage through mapping. The collected WCC data was 3,232. The climate data was collected from the Korea Meteorological Administration's meteorological data open portal. The machine learning model used DeepCrossing. The damage was calculated using climate data from the automated synoptic observing system (ASOS, 95 sites) by machine learning. The calculation of damage was the difference between the dry matter yield (DMY)normal and DMYabnormal. The normal climate was set as the 40-year of climate data according to the year of WCC data (1978-2017). The level of abnormal climate by temperature and precipitation was set as RCP 4.5 standard. The DMYnormal ranged from 13,845-19,347 kg/ha. The damage of WCC which was differed depending on the region and level of abnormal climate where abnormal temperature and precipitation occurred. The damage of abnormal temperature in 2050 and 2100 ranged from -263 to 360 and -1,023 to 92 kg/ha, respectively. The damage of abnormal precipitation in 2050 and 2100 was ranged from -17 to 2 and -12 to 2 kg/ha, respectively. The maximum damage was 360 kg/ha that the abnormal temperature in 2050. As the average monthly temperature increases, the DMY of WCC tends to increase. The damage calculated through the RCP 4.5 standard was presented as a mapping using QGIS. Although this study applied the scenario in which greenhouse gas reduction was carried out, additional research needs to be conducted applying an RCP scenario in which greenhouse gas reduction is not performed.
        4,200원
        129.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to promote the necessity for future research from the perspective of the indoor environment by analyzing the trend of domestic COVID-19 confirmed cases and examining previous quantitative research cases. The limitations of the qualitative management plan were identified by analyzing the trend of confirmed cases and deaths in Korea and the trend before and after the implementation of 'social distancing' and 'step-by-step daily recovery', which are actually being applied. The trend of initial and follow-up measures for the outbreak of infectious diseases in Korea is judged to be a case where the importance of qualitative and quantitative management should be confirmed to prepare absolute quarantine measures. The results suggest that examining previous research cases and preparing through advanced research for effective application.
        4,200원
        130.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Broad bean wilt virus 2 (BBWV2) is a species in the genus Fabavirus and family Secoviridae, which is transmitted by aphids and has a wide host range. The BBWV2 genome is composed of two single-stranded, positive-sense RNAs, RNA-1 and RNA-2. The representative symptoms of BBWV2 are mosaic, mottle, vein clearing, wilt, and stunting on leaves, and these symptoms cause economic damage to various crops. In 2019, Perilla fructescens leaves with mosaic and yellowing symptoms were found in Geumsan, South Korea. Reverse-transcription polymerase chain reaction (RTPCR) was performed with specific primers for 10 reported viruses, including BBWV2, to identify the causal virus, and the results were positive for BBWV2. To characterize a BBWV2 isolate (BBWV2-GS-PF) from symptomatic P. fructescens, genetic analysis and pathogenicity tests were performed. The complete genomic sequences of RNA-1 and RNA-2 of BBWV2-GS-PF were phylogenetically distant to the previously reported BBWV2 isolates, with relatively low nucleotide sequence similarities of 76-80%. In the pathogenicity test, unlike most BBWV2 isolates with mild mosaic or mosaic symptoms in peppers, the BBWV2-GS-PF isolate showed typical ring spot symptoms. Considering these results, the BBWV2-GS-PF isolate from P. fructescens could be classified as a new strain of BBWV2.
        4,500원
        131.
        2023.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        High-temperature oxidation of a Ni-based superalloy was analyzed with samples taken from gas turbine blades, where the samples were heat-treated and thermally exposed. The effect of Cr/Ti/Al elements in the alloy on high temperature oxidation was investigated using an optical microscope, SEM/EDS, and TEM. A high-Cr/high-Ti oxide layer was formed on the blade surface under the heat-treated state considered to be the initial stage of high-temperature oxidation. In addition, a PFZ (γ’ precipitate free zone) accompanied by Cr carbide of Cr23C6 and high Cr-Co phase as a kind of TCP precipitation was formed under the surface layer. Pits of several μm depth containing high-Al content oxide was observed at the boundary between the oxide layer and PFZ. However, high temperature oxidation formed on the thermally exposed blade surface consisted of the following steps: ① Ti-oxide formation in the center of the oxide layer, ② Cr-oxide formation surrounding the inner oxide layer, and ③ Al-oxide formation in the pits directly under the Cr oxide layer. It is estimated that the Cr content of Ni-based superalloys improves the oxidation resistance of the alloy by forming dense oxide layer, but produced the σ or μ phase of TCP precipitation with the high-Cr component resulting in material brittleness.
        4,000원
        132.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        월출산국립공원 내에 위치한 남생이(Mauremys reevesii) 대체서식지에서 사육 중인 남생이 15개체(암컷 6, 수컷 9)를 대상으로 개체 간 구애와 공격 행동을 관찰하여 사회적 상호작용을 알아보고자 하였다. 이를 위하여 2020년 5월 18일부터 2020년 10월 19일까지 연구지역에 CCTV를 설치하여 매주 3일(24시간/일), 총 64일 동안 녹화하였고 시간 당 10분 간격으로 분석하였다. 남생이의 구애행동은 총 884회 관찰되었고 수컷은 체중이 가장 가벼운 암컷(3회)보 다 가장 무거운 암컷(357회)에게 더 많은 빈도의 구애행동을 하였다. 남생이의 공격행동은 총 259회 관찰되었으며 암컷-암컷 간 30회, 수컷-수컷은 81회, 암컷-수컷은 148회 관찰되었다. 이를 바탕으로 파악한 우열관계는 전반적으로 암컷이 수컷보다 더 높게 나타났으며, 몸 크기가 클수록 순위가 높게 나타났다. 본 연구는 국내 최초로 남생이의 구애행동 빈도를 통해 번식가능성이 높은 개체를 확인하고 공격 행동에 따른 우열관계를 파악하였다. 연구결과는 멸종위기에 처한 남생이의 관리 및 보전을 위한 행동학적 기초 자료로 활용될 수 있으며, 남생이의 사회구조를 이해하는 데 도움이 될 것이다.
        4,000원
        133.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 데이터 기반 경제 활동의 비중이 급증하면서 데이터경제에 대한 논의가 활발하지만 우리나라 주요 산업별 데이터경제로의 전환을 체계적으로 분석하는 틀을 제시하는 연구는 많지 않다. 본 연구는 문헌연구를 통해 데이터경제의 주요 특징을 플랫폼(platform) 구축, 예측력(predictive power) 강화, 새로운 분석모델(new analytical model)의 활용으로 정리하고, 이에 입각하여 우리나라의 금융, 부동산, 의료 부문 간 데이터 기반 활동의 정도를 비교 분석한다. 분석 결과 금융, 부동산, 의료 부문별로 데이터경제 특징이 실현되고 있는 속도와 내용이 다르다는 것이 관찰되었다. 이는 데이터경제의 확산을 통해 경제 생산성 향상과 복지 증대를 위해서는 금융, 부동산, 의료 등 주요 산업 부문별로 차별화된 정책 접근이 필요 하다는 것을 시사한다.
        8,900원
        134.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 건설현장에서 장스팬 구조물이 증가함에 따라 콘크리트와 강재를 조합한 충전형합성보의 적용이 증가하고 있 다. 충전형합성보는 경제적이며 시공성이 향상되고 콘크리트 축열효과에 따라 내화성도 우수하다. 충전형합성보 내부에 휨성능 을 향상시키기 위해 Re-bar로 보강하여 사용한다. 이는 콘크리트 균열에 의해 부식 되어 내력저하를 유발한다. CFRP Re-bar는 경량이며 내부식성이 우수하다. 그러나 임계온도가 250℃로 낮기 때문에 화재에 취약으로 적절한 내화피복재를 적용해야된다. 따라서 열전달해석을 통해 내부 CFRP Re-bar가 보강된 충전형합성보의 온도분포를 확인하였다. 온도 상승에 따른 휨내력을 산 정하여 피복두께를 제안하고자 한다. 해석결과 단면크기에 상관없이 콘크리트 피복두께 40mm와 뿜칠내화피복재 20mm를 적용 하면 표준화재에서 3시간 내화성능을 확보하는 것으로 평가되었다.
        4,200원
        135.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        지구의 기후 변화를 유도하고 제어하는 가장 중요한 역할을 하는 것은 해양의 해류이다. 황해는 수심이 동해 에 비해 매우 얕고, 다양한 바람과 조류, 강물의 유입, 동중국해에서의 해수 유입 등 외력의 영향으로 해수의 순환과 해류가 상당히 복잡하다. 황해난류는 겨울철 황해의 대표적인 해류로서 겨울철 황해와 동중국해 바람 변동성과 밀접한 관련이 있으며, 황해의 수온과 염분 분포에 큰 영향을 주어서 중등학교 교과서에서 중요하게 다루어질 필요성이 있다. 2015 개정 교육과정 기반 중등학교 과학 및 지구과학 교과서의 황해난류와 관련된 내용을 분석하였다. 또한 해류의 시 간 변동성에 대한 교사들의 인식을 조사하기 위해 중등학교 과학 교사들을 대상으로 설문조사를 실시하였다. 대부분의 교사들은 황해난류가 우리나라 서해안으로 연중 북상하고 있으며 일반적인 난류와 같이 여름철에 강하다는 잘못된 지 식을 가지고 있는 것으로 나타났다. 황해난류는 해류의 세기가 강한 계절변동성을 가지는 북한한류와 달리 해류 자체가 연중 항시 존재하지 않으며 겨울철에만 발생하는 해류이다. 이러한 교사들의 교과내용 지식에 대한 오류는 북한한류가 겨울철에 강하다는 오개념을 가지게 된 연유와 유사한 배경을 가지고 있었다. 따라서 본 연구에서는 황해난류에 대한 교과서 내용의 오류를 분석하여 제시하였다. 또한 학생들과 교사들의 데이터 리터러시 함양을 위하여 탐구활동에서 활 용할 수 있는 황해난류에 대한 수업 자료를 개발하였다. 황해 해수면 온도를 가시화할 수 있는 GUI 프로그램을 소개하 였고, WOA (World Ocean Atlas) 2018 해양 실측 수온 및 염분자료와 국립해양조사원에서 생성한 해양 수치모델 재분 석자료를 활용하여 수온과 염분의 공간 분포를 도시하는 자료를 개발하여 제시하였다. 이러한 해양 자료를 활용한 데이 터 시각화과정은 교사들의 오개념을 개선하고, 나아가 학생들과 교사들의 해양 리터러시뿐만 아니라 데이터 리터러시도 제고하는 계기가 될 것으로 기대된다.
        6,000원
        136.
        2023.01 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        With a focus on the aspect of recruitment within “nurse manpower management,” this study examined the status and characteristics of employment of new graduate nurses in tertiary hospitals of Korea. It also explored the recruitment process and characteristics of new graduate nurses in foreign countries by referring to case studies. The new graduate nurse recruitment was carried out as an open hiring as a consequence of an analysis of recruitment announcements at 45 tertiary hospitals in Korea. The recruitment process began with document screening, followed by competency test, interviews, and physical examination. Around 80% of the institutions surveyed started document screening between June and August, and the timing of joining the hospital was determined by grades and hospital conditions. In other countries, new graduate nurses were hired by each ward throughout the year, and various forms of employment were used. In some countries, preceptorship programs or pre-hospital field trip programs were running. In Korea, recruitment of new graduate nurses is carried out by hospitals instead of wards. Therefore, it is essential to plan and implement a manpower allocation strategy to represent the desired department of the nurse as much as possible when assigning new graduate nurses. In addition, it is necessary to establish flexible employment options and working environment to encourage long-term service. Instead of manpower management policies focused on increasing the supply of nurses, it is necessary to come up with measures to address the actual causes of turnover, such as wage gaps, organizational culture, and improvement of working environment.
        4,000원
        138.
        2023.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ‘Tracers’ are bullets that emit light at the backside so that the shooter can see the trajectory of their flight. These light-emitting bullets allow snipers to hit targets faster and more accurately. Conventional tracers are all combustion type which use the heat generated upon ignition. However, the conventional tracer has a fire risk at the impact site due to the residual flame and has a by-product that can contaminate the inside of the gun and lead to firearm failure. To resolve these problems, it is necessary to develop non-combustion-type tracers that can convert heat to luminance, so-called ‘thermoluminescence (TL)’. Here, we highly improve the thermoluminescence properties of MgB4O7 through co-doping of Dy3++Ce3+ and Dy3++Na+. The presence of doping materials (Dy3+, Ce3+, Na+) was confirmed by XPS (X-ray photoelectron spectroscopy). The as-synthesized co-doped MgB4O7 was irradiated with a specific radiation dose and heated to 500 °C under dark conditions. Different thermoluminescence characteristics were exhibited depending on the type or amounts of doping elements, and the highest luminance of 370 cd/m2 was obtained when Dy 10 % and Na 5 % were co-doped.
        4,000원
        139.
        2023.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the rocking behavior of unreinforced masonry walls and wall piers under cyclic loading. Based on the benchmark tests, the characteristics of load-deformation relations in masonry walls with rocking failure were captured, focusing on observed deformation modes. The rocking strengths of masonry walls (i.e., peak and residual strengths) were evaluated, and the effects of opening configurations on the masonry wall strength were examined. The deformation capacity of the rocking behavior and the hysteresis shape of the load-deformation relations were also identified. Based on the results, modeling approaches for the rocking behavior of masonry walls were discussed.
        4,000원
        140.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, the mechanical properties of glass fiber reinforced plastic (GFRP) rebar, which has been applied as an concrete reinforcement, and produced carbon fiber reinforced plastic (CFRP) grid were compared to develop a concrete reinforcement material with excellent mechanical properties. In addition, the mechanical properties of CFRP prepared with each molding process were evaluated. Three molding processes were evaluated: prepreg oven bagging, reaction injection molding (RIM), and pultrusion. The tensile strength of the CFRP grid prepared through pultrusion was 2.85GPa, the elastic modulus was 169.81GPa, and the strain was 1.68%, which was 2.85 times better in tensile strength, and 2.83 times better in elastic modulus compared mechanical properties of GFRP rebar. The strain was confirmed to be equivalent to GFRP rebar.
        4,000원