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        검색결과 3,188

        41.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we examined dimensional changes in processing carbon fiber composites using a cost-competitive domestic high-speed router. Lacking temperature compensation features found in typical machines, it faces increased defect rates due to temperature fluctuations during processing. To mitigate this, we defined specific processing temperature conditions, established hole positions as distance references for various temperatures, and measured dimensional changes. This enabled us to calculate necessary dimensional corrections, minimizing thermal deformation.
        4,000원
        42.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Raman distributed temperature sensor can be used as temperature instruments as well as monitoring abnormalities in next-generation nuclear systems. Since noise reduction and Measuring Frequency enhancement are required, integration time adjustment has been mainly used so far. In this study, a new data processing method using Moving Average Filter was analyzed to see if noise reduction and Measuring Frequency could be reduced, and improvement measures were suggested.
        4,000원
        43.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cars using diesel have always had problems with reducing exhaust fumes, and have been studied steadily in this regard. There were studies on the remanufacturing effect of DOC catalyst deactivated by diesel vehicle smoke reduction device, analysis of vehicle fire accident cases caused by damage to diesel vehicle smoke reduction device, and related studies on the remanufacturing effect of diesel vehicle smoke reduction device DPF. This study is also to develop an exhaust flow control unit suitable for an exhaust engine to completely burn smoke generated by an engine using a diesel engine in a low temperature exhaust gas. The main systems to be developed are high-performance heaters, burner structures that can maintain ignition in exhaust flows, and exhaust flow control units that reduce exhaust gas backflow effects caused by diesel engines.
        4,000원
        44.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, numerical analysis was performed for the purpose of analyzing the flow characteristics and performance according to the change in the inflow hydrogen temperature and differential pressure of the receptacle of the hydrogen charging system. The pressure distribution and turbulent kinetic energy in the filter area were analyzed by changing the outlet pressure condition under the inlet hydrogen temperature condition, and the flow velocity change at the outlet was compared and analyzed. As a result of the analysis, as the differential pressure decreased, the flow rate at the outlet of the receptacle decreased by up to about 70% at the 2.86 MPa condition compared to the 1.86 MPa condition, and the mass flow rate decreased by about 56.5% at the maximum. It was found that the standard CV performance was not satisfied when the differential pressure at the inlet and outlet was 1.12 MPa or less under the 363K temperature condition.
        4,000원
        45.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        ars using diesel have always had problems with reducing exhaust fumes, and have been studied steadily in this regard. There were studies on the remanufacturing effect of DOC catalyst deactivated by diesel vehicle smoke reduction device, analysis of vehicle fire accident cases caused by damage to diesel vehicle smoke reduction device, and related studies on the remanufacturing effect of diesel vehicle smoke reduction device DPF. This study also developed an optimized system for complete combustion of smoke generated by institutions using diesel engines in low-temperature exhaust gases. The main systems to be developed are high-performance heaters, burner structures that can maintain ignition in exhaust flows, and exhaust flow control units that reduce exhaust gas backflow effects caused by diesel engines.
        4,000원
        46.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to assess and determine the optimal model for predicting the full bloom date of ‘Fuji’ apples across South Korea. We evaluated the performance of four distinct models: the Development Rate Model (DVR)1, DVR2, the Chill Days (CD) model, and a sequentially integrated approach that combined the Dynamic model (DM) and the Growing Degree Hours (GDH) model. The full bloom dates and air temperatures were collected over a three-year period from six orchards located in the major apple production regions of South Korea: Pocheon, Hwaseong, Geochang, Cheongsong, Gunwi, and Chungju. Among these models, the one that combined DM for calculating chilling accumulation and the GDH model for estimating heat accumulation in sequence demonstrated the most accurate predictive performance, in contrast to the CD model that exhibited the lowest predictive precision. Furthermore, the DVR1 model exhibited an underestimation error at orchard located in Hwaseong. It projected a faster progression of the full bloom dates than the actual observations. This area is characterized by minimal diurnal temperature ranges, where the daily minimum temperature is high and the daily maximum temperature is relatively low. Therefore, to achieve a comprehensive prediction of the blooming date of ‘Fuji’ apples across South Korea, it is recommended to integrate a DM model for calculating the necessary chilling accumulation to break dormancy with a GDH model for estimating the requisite heat accumulation for flowering after dormancy release. This results in a combined DM+GDH model recognized as the most effective approach. However, further data collection and evaluation from different regions are needed to further refine its accuracy and applicability.
        4,300원
        47.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 미국 해양 대기청(NOAA)의 NOAA-20 위성에 장착된 차세대 고해상도 복사계인 VIIRS로부터 산출된 적외 해수면온도의 자료를 수집하고, 실측 자료와의 일치점을 생산하여 한반도 주변 해역에서의 정확도를 검증 하였다. 2020년 5월부터 2023년 6월까지 최근 3년간의 자료를 사용하였고, 총 75,700개의 일치점을 생산하였다. NOAA-20/VIIRS 해수면온도는 표층 뜰개 부이 관측 해수면온도와 비교해보았을 때 약 0.52K의 평균 제곱근 오차와 – 0.12 K의 평균 편차를 보였고, 이는 전구 해역을 대상으로 한 기존의 정확도 검증 연구 결과값을 상회하는 수치였다. NOAA-20 해수면온도의 오차 특성 분석 결과 겨울과 봄에는 음의 편차가, 여름철에는 양의 편차를 보이는 계절적 특 성이 나타났으며, 15-16시에 최대 평균 제곱근오차, 최대 양의 편차 및 22-24시에 최소 평균제곱근오차, 최소 편차를 가지는 일간 변화를 보였다. 이외에도 NOAA-20 해수면온도의 오차는 풍속, 위성 천정각, 연안으로부터의 거리, 해수면 온도의 공간 구배 크기에 영향을 받아 변동하는 특성이 나타났다. 전반적으로 위성 해수면온도의 편차값은 14ms1 이 상의 풍속 범위에서 풍속이 커질수록 양의 방향으로 증가하는 경향을 보였으며, 5 m s1 이하의 낮은 풍속 범위에서는 풍속이 약해질수록 낮/밤 자료에 따라 각각 양의 방향, 음의 방향으로 편차가 증가하였다. 위성 천정각이 커질수록 해 수면온도의 오차 범위는 급격하게 증가하였으며, 연안에 근접할수록 (<300 km) 위성 해수면온도의 오차가 증가하는 것 을 확인할 수 있었다. 해수면온도의 공간 구배는 그 크기가 커질수록 위성 해수면온도의 평균 제곱근 오차를 증폭시키 는 경향이 나타났다. 국지적인 해역에서의 위성 해수면온도 정확도 및 오차 특성은 전구 해역에서의 전반적인 특성과는 다르게 나타날 수 있다는 점을 고려할 때 본 연구는 향후 한반도 주변해에서 VIIRS 해수면온도를 활용하기 위한 선행 연구로 해수면온도 오차의 변동 특성 및 분포에 대한 깊은 이해가 필요함을 시사한다.
        4,500원
        48.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effects of exogenous sodium nitroprusside (SNP, nitric oxide donor) on the growth, yield, photosynthetic characteristics, and antioxidant enzyme activity of kimchi cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) was studied under the low temperature conditions. Kimchi cabbages were treated with SNP of three concentrations (7.5, 15, 30 mg·L-1) for three times at four-day intervals and exposed to low temperature (16/7°C) stress for seven days. SNP treatment induced increases of net photosynthetic rate (Pn), stomatal conductance (Gs), intracellular CO2 concentration (Ci) and transpiration rate (Tr) under the stress condition with the highest level after the third treatment. The contents of malondialdehyde (MDA) and H2O2 were significantly lower in the treatment of SNP compared to the non-treated control. The activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), increased in treated plants by up to 38, 187, 24 and 175%, respectively compared to the non-treated control. SNP-treated and untreated plants had similar growth characteristics. Compared to the control group, SNP-treatment increased fresh weight and leaf area by 5%. Overall, our findings suggest that the application of sodium nitroprusside to the leaves contributes to reducing physiological damage and enhancing the activities of antioxidant enzymes, thereby improving low temperature stress tolerance in kimchi cabbage.
        4,000원
        49.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 국내 가정에서 사용하고 있는 냉장고 및 냉 동고의 온도 분포에 대한 현황을 파악하기 위하여 냉장고 대상 25가구, 냉동고 대상 25가구를 선정하고 온도 측정 을 시행하였다. 가정용 냉장 및 냉동고의 실제 공간상의 온도 분포 조사 결과, 냉장고 대상 가구에서 측정된 온도 는 최저 -8.2oC, 최고 15.8oC, 평균 3.73oC로 조사되었으며, 공간 위치별 온도 분포는 문 보관 칸 5.06±1.69oC, 내부 벽면 4.18±1.19oC, 내부 보관함 3.41±1.36oC로 내부 보관함 의 온도가 가장 낮았고, 각 위치에서 상단 및 하단의 유의 적인 온도 차이는 문 보관 칸에서만 확인되었다(P<0.01). 냉 동고 대상 가구에서 측정된 온도는 최저 -30.3oC, 최고 0.7oC, 평균 -17.95oC로 조사되었으며, 공간 위치별 온도 분포는 문 보관 칸 -17.19±1.68oC, 내부 벽면 -17.81±1.07oC, 내부 보관함 -18.78±1.72oC로 냉장고 결과와 동일하게 내부 보 관함의 온도가 가장 낮고, 문 보관 칸에서만 상·하단의 유 의적인 온도 차가 확인되었다(P<0.01). 냉장·냉동고 내에 서 위치별 최대 온도 차이는 각각 2.18oC, 2.02oC로 확인 되었으며, 결론적으로 냉장·냉동고 전체의 온도가 일정하 게 유지되는 것이 아니며, 보관되는 위치별로 유의적인 편 차가 존재하는 것으로 나타났다. 이에 따라 냉장·냉동고 제조사와 공공기관에서 식품별 권장 보관 위치를 고객들 에게 적극적으로 권고하고, 각 가정에서는 온도 변화에 민 감한 식품을 보관할 경우 문쪽 보관을 지양하는 등 보관 관리 의식을 가져야 할 것으로 사료된다.
        4,000원
        50.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop a model for predicting the growth of kimchi cabbage using image data and environmental data. Kimchi cabbages of the ‘Cheongmyeong Gaual’ variety were planted three times on July 11th, July 19th, and July 27th at a test field located at Pyeongchang-gun, Gangwon-do (37°37′ N 128°32′ E, 510 elevation), and data on growth, images, and environmental conditions were collected until September 12th. To select key factors for the kimchi cabbage growth prediction model, a correlation analysis was conducted using the collected growth data and meteorological data. The correlation coefficient between fresh weight and growth degree days (GDD) and between fresh weight and integrated solar radiation showed a high correlation coefficient of 0.88. Additionally, fresh weight had significant correlations with height and leaf area of kimchi cabbages, with correlation coefficients of 0.78 and 0.79, respectively. Canopy coverage was selected from the image data and GDD was selected from the environmental data based on references from previous researches. A prediction model for kimchi cabbage of biomass, leaf count, and leaf area was developed by combining GDD, canopy coverage and growth data. Single-factor models, including quadratic, sigmoid, and logistic models, were created and the sigmoid prediction model showed the best explanatory power according to the evaluation results. Developing a multi-factor growth prediction model by combining GDD and canopy coverage resulted in improved determination coefficients of 0.9, 0.95, and 0.89 for biomass, leaf count, and leaf area, respectively, compared to single-factor prediction models. To validate the developed model, validation was conducted and the determination coefficient between measured and predicted fresh weight was 0.91, with an RMSE of 134.2 g, indicating high prediction accuracy. In the past, kimchi cabbage growth prediction was often based on meteorological or image data, which resulted in low predictive accuracy due to the inability to reflect on-site conditions or the heading up of kimchi cabbage. Combining these two prediction methods is expected to enhance the accuracy of crop yield predictions by compensating for the weaknesses of each observation method.
        4,200원
        51.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study provides fundamental information on the temperature variations in tunnel structures during severe fire events. A fire event in a tunnel can drastically increase the internal temperature, which can significantly affect its structural safety. METHODS : Numerical simulations that consider various fire conditions are more efficient than experimental tests. The fire dynamic simulator (FDS) software, based on computational fluid dynamics (CFD) and developed by the National Institute of Standards and Technology, was used for the simulations. The variables included single and multiple accidents involving heavy goods vehicles carrying 27,000 liters of diesel fuel. Additionally, the concrete material characteristics of heat conductivity and specific heat were included in the analysis. The temperatures of concrete were investigated at various locations, surfaces, and inside the concrete at different depths. The obtained temperatures were verified to determine whether they reached the limits provided by the Fire Resistance Design for Road Tunnel (MOLIT 2021). RESULTS : For a fire caused by 27,000 liters of diesel, the fire intensity, expressed as the heat release rate, was approximately 160 MW. The increase in the carrying capacity of the fire source did not significantly affect the fire intensity; however, it affected the duration of the fire. The maximum temperature of concrete surface in the tunnel was approximately 1400 ℃ at some distance away in a longitudinal direction from the location of fire (not directly above). The temperature inside the concrete was successfully analyzed using FDS. The temperature inside the concrete decreased as the conductivity decreased and the specific heat increased. According to the Fire Resistance Design for Road Tunnel (MOLIT 2021), the internal temperatures should be within 380 ℃ and 250 ℃ for concrete and reinforcing steel, respectively. The temperatures were found to be approximately 380 ℃ and 100 ℃ in mist cases at depths of 5 cm and 10 cm, respectively, inside the concrete. CONCLUSIONS : The fire simulation studies indicated that the location of the maximum temperature was not directly above the fire, possibly because of fire-frame movements. During the final stage of the fire, the location of the highest temperature was immediately above the fire. During the fire in a tunnel with 27,000 liters of diesel, the maximum fire intensity was approximately 160 MW. The capacity of the fire source did not significantly affect the fire intensity, but affected the duration. Provided the concrete cover about 6 cm and 10 cm, both concrete and reinforcing steel can meet the required temperature limits of the Fire Resistance Design for Road Tunnel (MOLIT 2021). However, the results from this study are based on a few assumptions. Therefore, further studies should be conducted to include more specific numerical simulations and experimental tests that consider other variables, including tunnel shapes, fire sources, and locations.
        4,200원
        52.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기후변화 영향으로 이상고수온, 태풍, 홍수, 가뭄 등 재난 및 안전 관리기술은 지속적으로 고도화를 요구받고 있으며, 특히 해 수면 온도는 한반도 주변에서 발생되는 여름철 적조 발생과 동해안 냉수대 출현, 소멸 등에 영향을 신속하게 분석할 수 있는 중요한 인자 이다. 따라서, 본 연구에서는 해수면 온도 자료를 해양 이상현상 및 연구에 적극 활용되기 위해 통계적 방법과 딥러닝 알고리즘을 적용하 여 예측성능을 평가하였다. 예측에 사용된 해수면 수온자료는 흑산도 조위관측소의 2018년부터 2022년까지 자료이며, 기존 통계적 ARIMA 방법과 Long Short-Term Memory(LSTM), Gated Recurrent Unit(GRU)을 사용하였고, LSTM의 성능을 더욱 향상할 수 있는 Sequence-to-Sequence(s2s) 구조에 Attention 기법을 추가한 Attention Long Short-Term Memory (LSTM)기법을 사용하여 예측 성능 평가를 진행하 였다. 평가 결과 Attention LSTM 모델이 타 모델과 비교하여 더 좋은 성능을 보였으며, Hyper parameter 튜닝을 통해 해수면 수온 성능을 개 선할 수 있었다.
        4,000원
        53.
        2023.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        인공위성은 최첨단 기술로써 시공간적 관측제약이 적어 해양 사고에 효과적 대응과 해양 변동 특성 분석 등으로 각국의 국가 기관들이 위성 정보를 활용하고 있다. 하지만 고해상도 위성 관측 기반 해수면 온도 자료(Operational Sea Surface Temperature and Sea Ice Analysis, OSTIA)는 위성의 기기적, 또는 지리적 오류와 구름으로 인해 낮게 관측되거나 공백으로 처리되며 이를 복원하기까지 수 시간이 소요된다. 본 연구는 최신 딥러닝 기반 알고리즘인 LaMa 기법을 활용하여 결측된 OSTIA 자료를 복원하고, 그 성능을 기존에 이용되어 온 세 가지 영상처리 기법들의 성능과 비교하여 평가하였다. 결정계수(R²)와 평균절대오차(MAE) 값을 이용하여 각 기법의 위성 영상 복원 성 능을 평가한 결과, LaMa 알고리즘을 적용하였을 때의 R²과 MAE 값이 각각 0.9 이상, 0.5℃ 이하로, 기존에 사용되어 온 쌍 선형보간법, 쌍 삼차보간법, DeepFill v1 기법을 적용한 것보다 더 우수한 성능을 보였다. 향후에는 현업 위성 자료 제공 시스템에 LaMa 기법을 적용하여 그 가능성을 평가해 보고자 한다.
        4,000원
        55.
        2023.10 구독 인증기관·개인회원 무료
        가송이(Tricholoma bakamatsutake Hongo)는 주름버섯목(Agaricales), 송이과(Tricholomataceae)에 속 하는 외생균근성 버섯류의 하나로, 송이(T. matsutake)와 일반적인 외형이 거의 비슷하며, 송이향과 맛이 강하게 나기 때문에 이 두 균종은 쉽게 혼동되며, 실제 분류 및 계통발생학적으로도 가송이와 송이는 유연 관계가 있는 것으로 밝혀졌다. 가송이는 한국, 일본, 대만, 중국의 신갈나무 등과 같은 활엽수림에 분포하는 것으로 알려져 있으며, 최근에는 제주도 구실잣밤나무림에서 발견되었다. 가송이는 균사생장이 매우 느려 연구에 어려움이 많아 균사배양 최적 조건을 구명하고자 본 연구를 실시하였다. 온도에 따른 가송이 균주 별 균사생장 특성을 조사한 결과, 모든 균주에서 25℃에서 가장 균사생장속도가 가장 빨랐으며, 특히 3833 균주가 다른 균주에 비해 약 1.5배 빠른 것으로 조사되었다.
        56.
        2023.10 구독 인증기관·개인회원 무료
        Spodoptera litura is an omnivorous pest that damages more than 120 types of crops. It is widely distributed throughout the tropics, subtropics, and temperate zones. It is a major pest that causes damage by explosively increasing in density in a short period of time due to its excellent mobility and reproductive ability. S. litura was studied at five constant temperatures (15.0, 20.0, 25.0, 30.0, and 35.0℃), 65±5% relative humidity (RH), and 14L:10D photoperiods. The development period for eggs and larvae tended to become shorter as temperature increased. The growth period of egg, larva, and pupa by 25℃ temperature was 4.0, 32.3, and 12.6 days, respectively.
        57.
        2023.10 구독 인증기관·개인회원 무료
        Spodoptera species (S. exigua and S. litura) are important pests of several crops and vegetables in Korea. We investigated development processes of Spodoptera species under constant temperatures (20, 25 and 30 oC) regimes and relative humidity (RH) (30-35, 50-55, 70-75, and 90-95%) conditions. We collected eggs of Spodoptera species by releasing them into a rectangular box inner walls covered with a sheet of white paper. Temperature and RH significantly impacted on oviposition, immature survival, adult emergence and longevity of Spodoptera species. Maximum number of eggs, shorter developmental time, higher adult emergence with longer longevity were reported in 70-75% at 30 oC. Minimal eggs and larval survival were recorded in 30-35% and 90-95% RH, respectively. This results suggest that temperature and RH had individual apparent effect on the developmental processes of Spodoptera species instead interactive effect. Therefore, there is chance to cause a significant damage to field crops and vegetables in 70-75% at 30 oC.
        58.
        2023.10 구독 인증기관·개인회원 무료
        We investigated the functional response of aphid parasitoid, Aphidius colemani Viereck (Hymenoptera: Braconidae), on the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) at four different constant temperatures (15, 20, 25 and 30℃). Seven host densities (2, 4, 8, 16, 32, 64, and 128) were used during a 24-h period. A type III functional response for A. colemani was fit separately at each constant temperature. The estimated handling times at 15, 20, 25, and 30℃ were 0.85, 0.61, 0.41 and 0.88 day, respectively. The proportion of aphids that were parasitized showed the similar characteristics curve at four different constant temperatures.
        59.
        2023.10 구독 인증기관·개인회원 무료
        Although ethylformate and phosphine fumigants are widely used for pest quarantine, studies related to their mechanism of action and metabolic physiological changes in Drosophila models are still unclear. In this study, we investigated how key metabolites altered by fumigants and cold treatment are associated with and affect insect physiology by comparative metabolome analysis. Fumigant treatment significantly altered cytochrome P450 and glutathione metabolites involved in the detoxification mechanism and showed lower expression of PGF2α involved in the immune response compared to the control. Additionally, most of the metabolites functioned in metabolic pathways related to the biosynthesis of amino acids, nucleotides and cofactors.
        60.
        2023.10 구독 인증기관·개인회원 무료
        The growth characteristics according to temperature conditions were investigated in the breeding room of the Sericulture & Entomology Experiment Station for Oriental garden crickets(Teleogryllus emma Ohmachi et Matsuura) and Modeagali-crickests(Loxoblemmus doenitzi Stein) collected from the lawns of Byeonsan-myeon, Buan-gun, Jeollabuk-do. The temperature conditions were 6 treatments from 15°C to 40°C at 5°C intervals using a multi-incubator, and the development period and mortality rate by age were compared using the 28°C breeding room conditions as a control. For T. emma, the higher the temperature, the shorter the total development period was, and the same trend was observed for the growth period by age stage. However, at low temperatures of 15°C and 20°C, all died after the third instar, and at high temperatures above 35°C, all died during development. At 25°C and 30°C, they developed normally, and the mortality rate was about 25%. The L. doenizi had the same tendency as the T. emma, with the higher the temperature, the shorter the development period. The total development period was 57.7 days at 25°C, which was similar to the T. emma's 55.9 days, and the mortality rate was the lowest at 44% at 25°C.
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