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        검색결과 738

        61.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A new free-living marine nematode species of the genus Pseudosteineria Wieser, 1956 affiliated with the family Xyalidae is described based on specimens collected from the sediment of a subtidal benthic environmental habitat in the East Sea, Korea. Pseudosteineria varisetis sp. nov differed from its congeners by the combination of the following characteristics: a relatively long body (1,628-1,691 μm long in males), a circular amphideal fovea situated behind the subcephalic setae, the presence of lateral cuticular alae starting from behind the nerve ring, the presence of eight groups of long subcephalic setae, the presence of irregularly distributed variable lengths of somatic setae on the body, solid spicules (43.2-43.9 μm long) with a cephalated proximal end, a long tubular shaped gubernaculum with dorsal swelling, and a conico-cylindrical tail with two to four terminal setae. In this report, we provide a taxonomic description and illustrations of a new species of the genus Pseudosteineria by differential interference contrast microscopy.
        4,000원
        62.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Admirandus multicavus Belogurov and Belogurova, 1979, a new record of free-living marine nematode species belonging to family Oncholaimidae is reported based on the specimens collected from the intertidal sediments of Korea. Admirandus multicavus is characterized by the following unique characteristics: cephalic setae (1-2 μm long), spicules (71-126 μm long) and gubernaculum (15-31 μm long), midventral preanal supplementary organ, three glandular duct openings of the Demanian system, and stoma length measuring twice the width. A comparative analysis of the biogeographical and ecological characteristics of Admirandus species is presented. DIC (Differential interference contrast) photomicrographs of the species are also provided herein. This report represents the first taxonomic analysis of the genus Admirandus Belogurov and Belogurova, 1979 discovered from the Korean seawaters.
        4,000원
        63.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Two new free-living marine nematodes of the genus Belbolla Andrássy, 1973 belonging to family Enchelidiidae are newly described based on specimens obtained from a shallow subtidal sediment of the western and southern outermost islands of Korea. Belbolla koreensis sp. nov. differs from other species of the genus by the combination of the following characteristics: longer body length (3,080-3,462 μm long), eight oesophageal bulbs in the posterior region of pharynx, well-developed two winged precloacal supplements (anterior precloacal supplement slightly longer than posterior one: 47-59 μm vs. 43-46 μm long), strongly arcuated, very thick, L - shaped spicule (122- 127 μm long, 1.7-1.9 anal body diameter (a.b.d.) long) with three separated blunt distal tips, and well-developed relatively long cylindrical shaped gubernacular apophysis with blunt teeth covering two thirds of the dorsal margin (57-58 μm long, 0.8-0.9 a.b.d. long). Belbolla hoonsooi sp. nov. is characterized by the following combination of characteristics: longer body length (3,494 μm long), eight oesophageal bulbs in the posterior region of pharynx, well-developed two winged precloacal supplements (anterior precloacal supplement slightly longer than posterior one: 43 μm vs. 36 μm long), strongly arcuated, L - shaped spicule (119 μm long, 1.5 a.b.d. long) with three separated blunt distal tip, and well-developed relatively long inverted triangle shaped gubernacular apophysis with blunt teeth covering half of the dorsal margin (45 μm long, 0.6 a.b.d. long). Detailed morphological characteristics and illustrations of two new Belbolla nematodes from the Korean seawaters were provided by differential interference contrast microscopy. Comparative tables on biogeographical and morphological characteristics of Belbolla species are also provided herein.
        4,300원
        64.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This article suggests the machine learning model, i.e., classifier, for predicting the production quality of free-machining 303-series stainless steel(STS303) small rolling wire rods according to the operating condition of the manufacturing process. For the development of the classifier, manufacturing data for 37 operating variables were collected from the manufacturing execution system(MES) of Company S, and the 12 types of derived variables were generated based on literature review and interviews with field experts. This research was performed with data preprocessing, exploratory data analysis, feature selection, machine learning modeling, and the evaluation of alternative models. In the preprocessing stage, missing values and outliers are removed, and oversampling using SMOTE(Synthetic oversampling technique) to resolve data imbalance. Features are selected by variable importance of LASSO(Least absolute shrinkage and selection operator) regression, extreme gradient boosting(XGBoost), and random forest models. Finally, logistic regression, support vector machine(SVM), random forest, and XGBoost are developed as a classifier to predict the adequate or defective products with new operating conditions. The optimal hyper-parameters for each model are investigated by the grid search and random search methods based on k-fold cross-validation. As a result of the experiment, XGBoost showed relatively high predictive performance compared to other models with an accuracy of 0.9929, specificity of 0.9372, F1-score of 0.9963, and logarithmic loss of 0.0209. The classifier developed in this study is expected to improve productivity by enabling effective management of the manufacturing process for the STS303 small rolling wire rods.
        4,200원
        65.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In applying LCD to TV application, one of the most significant factors to be improved is image sticking on the moving picture. Despite the development of technology for fast screen signal processing, it is very difficult to compose a high-quality screen due to the limitation of blinking driving due to the long afterglow time of the backlight. As the Single-LVDS signal system evolves from the Quad Signal Package to respond to 3D, the problem of processing faster signals within a set time is occurring. is becoming In this study, the aim was to realize this operation within 1 frame time by using the blinking backlight, and the existing cold cathode tube lamp was used as the light source. In general, cold cathode tube lamps have a long afterglow time of green, which is responsible for the main emission wavelength, so it is difficult to realize the above characteristics. A backlight capable of flickering within the time frame of the video frame was manufactured, and by using it, it was possible to confirm the effect of resolving the afterimage in a moving image by leaps and bounds.
        4,000원
        66.
        2021.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        흰점박이 꽃무지 유충은 식품원료로서 영양적 가치가 우수하지만 소비자의 기호도 개선을 위해 가공공정기술의 적용을 검토할 필요가 있다. 따라서 본 연구에서는 흰점박이 꽃무지 유충을 다양한 추출 공정(온수, 열수, 초음파, 고압 추출)으로 처리하여 추출물을 제조하였고 유리아미 노산 함량과 지방산 조성의 변화를 관찰하였다. 유리아미 노산 함량 및 조성은 모든 추출물에서 향상되었다. 특히 고압추출물에서 유리아미노산 총량과 필수아미노산 분포 비율이 각각 2.9, 4.6배 증가하여 고압 처리가 흰점박이 꽃무지 유충의 유리아미노산 함량 증가 및 조성 개선에 가장 큰 효과가 있다는 것을 확인하였다. 한편 지방산 조성은 초음파 추출물과 고압 추출물에서 개선되었다. 원료에 비해 포화지방산 비율은 감소하고 불포화지방산 비율이 증가하여 기존의 주요 단백질급원인 육류에 비해 불포화지방산 섭취 측면에서 유리할 것으로 판단된다. 따라서 흰점박이 꽃무지 유충은 초음파 추출과 고압 추출에 의해 유리아미노산과 지방산의 품질 특성이 개선될 수 있으므로 해당 추출물은 식약용 소재로서의 활용 가능성이 매우 높을 것으로 판단된다. 또한, 추후 초음파 추출과 고압 추출 공정의 최적화 연구가 이루어진다면 흰점박이 꽃무지 유충의 활용가치는 더욱 높아질 것으로 예상된다.
        4,000원
        72.
        2021.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        (Bi1/2Na1/2)TiO3 (BNT)-based ceramics are considered promising candidates for actuator application owing to their excellent electromechanical strain properties However, to obtain large strain properties, there remain several issues such as thermal stability and high operating fields. Therefore, this study investigates a reduction of operating field in (0.98-x)Bi1/2Na1/ 2TiO3-0.02 BiAlO3-xSrTiO3 (BNT-2BA-100xST, x = 0.20, 0.21, 0.22, 0.23, and 0.24) via analyses of the microstructure, crystal structure, dielectric, polarization, ferroelectric and electromechanical strain properties. The average grain size of BNT-2BA- 100xST ceramics decreases with increasing ST content. Results of polarization and electromechanical strain properties indicate that a ferroelectric to relaxor state transition is induced by ST modification. As a consequence, a large electromechanical strain of 592 pm/V is obtained at a relatively low electric field of 4 kV/mm in 22 mol% ST-modified BNT-2BA ceramics. We believe that the materials synthesized in this study are promising candidates for actuator applications.
        4,000원
        73.
        2021.10 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        산업이 발달함에 따라 이산화탄소, 휘발성 유기 화합물, 일산화탄소 등과 같은 독성 가스의 감지 및 모니터링이 중요시되고 있다. 새롭게 합성된 0 차원의 비납계 무기 페로브스카이트 소재는 광학적 방법과 전기적 방법을 융합하여 사용할 수 있는 가스 센서 특성을 가진다. 친환경 가스 센서는 결정의 상변이를 기반으로, 광학 및 전기적 특성 변화를 가져 하이드록실기 감지가 가능하며, 하이드록실기 극성과의 상관관계를 통해 차세대 센서 소자로의 응용 가능성이 기대된다.
        3,000원
        75.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        지구 온난화 이슈에서 가장 고질적인 문제 중 하나는 온실가스의 배출이다. 다양한 온실 가스 중 가장 높은 비중을 차지하는 이산화탄소(CO2)는 이를 분리하기 위해 연구자들이 지속적으로 연구를 진행해오고 있다. 이러한 관점에서 본 연구에서는 이산화탄소 기체를 분리하기 위해 poly(vinyl alcohol) (PVA) 기반 공중합체를 제조하여 기체 분리막에 활용했다. 공중합체는 자유 라디칼 중합법을 활용했으며, 곁사슬을 위한 단량체로 아크릴산(acrylic acid)를 사용하여 PVA-g-PAA (VAA) 그래프트 공중합체를 제조했다. 본 공중합체를 이산화탄소 기체분리막에 적용한 사례는 최초이며, 폴리설폰 지지체에 복합막 형태로 제조했다. 공중합체 합성 결과는 FT-IR을 통해, 합성한 공중합체 의 거동은 TEM과 DSC, TGA를 통해 분석하였다. AA 그래프팅을 통해 공중합체는 나노 구조를 형성하며, PVA의 결정화도를 급격하게 감소시켜 이산화탄소의 용해도를 증가시켰고, 이는 이산화탄소 기체 분리 성능을 향상시켰다. 이를 통해 이산화탄소 분리막 분야에 용액-확산 및 그래프팅 방법이라는 새로운 접근법을 제시하였다.
        4,000원
        77.
        2021.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        연구자는 2025년 고교학점제 전면 도입을 앞두고 진로 탐색 역량 및 자기 주도적 학습역량 함양을 위한 중학교 한문과 교육과정과 고등학교 한문과 교육과정과의 연계성을 강화해야 한다고 생각한다. 특히, 한문과가 고교학점제 기반 진로 맞춤형 선택중심 교육과정에서 선택될 수 있도록 하기 위해서는 중학교 자유학년제에서 학생 진로 맞춤형 한문과 교육과정 토대를 마련하고, 중학생 수준에 맞는 한문과 교육과정의 집중 운영과 수업 및 평가 내실화를 통한 한문 학습의 질 제고가 필요하다. 또한, 자유학년제와 고교학점제의 공통 목표는 학생들의 미래 핵심역량 신장에 있다. 이 같은 목표를 달성하기 위해서는 중학교 한문과 교육과정을 자유학년제 비전에 맞게 수정⋅보완하고, 중학생의 진로 성숙도를 제고하여 고교학점제로 확대⋅이행될 수 있도록 학생의 관심사, 학교 여건 등을 고려하여 다양하게 재구성해야 한다. 따라서 이 연구에서는 자유학년제 주제선택 활동 관련 선행연구와 자유학년제 관련 한문과 수업 동향을 분석하여 진로 탐색을 위한 자유학년제 한문교과형 주제선택 활동을 구안하고 수업에 적용 해보고자 한다. 그리고 선행연구 분석을 토대로 구안한 진로 탐색을 위한 한문교과형 주제선택 활동 사례를 분석하여 앞으로 자유학년제에서의 한문 수업을 진로활동과 연계하여 효과적으로 운영하는 데 시사점을 제공하고자 한다.
        6,900원
        79.
        2021.05 구독 인증기관 무료, 개인회원 유료
        This study suggests a machine learning model for predicting the production quality of free-machining 303-series stainless steel small rolling wire rods according to the manufacturing process's operation condition. The operation condition involves 37 features such as sulfur, manganese, carbon content, rolling time, and rolling temperature. The study procedure includes data preprocessing (integration and refinement), exploratory data analysis, feature selection, machine learning modeling. In the preprocessing stage, missing values and outlier are removed, and variables for the interaction between processes and quality influencing factors identified in existing studies are added. Features are selected by variable importance index of lasso regression, extreme gradient boosting (XGBoost), and random forest models. Finally, logistic regression, support vector machine, random forest, and XGBoost is developed as a classifier to predict good or defective products with new operating condition. The hyper-parameters for each model are optimized using k-fold cross validation. As a result of the experiment, XGBoost showed relatively high predictive performance compared to other models with accuracy of 0.9929, specificity of 0.9372, F1-score of 0.9963 and logarithmic loss of 0.0209. In this study, the quality prediction model is expected to be able to efficiently perform quality management by predicting the production quality of small rolling wire rods in advance.
        4,000원
        80.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a new method of rapid preparation of carbon nanotube (CNT) solution with highly dispersed morphology by free arc excitation is proposed, which shortens the time of the preparation of CNT solution with low concentration. The principle is that the high-energy flow density heat generated by the free arc makes the vaporizable substance coated on the surface of CNTs vaporize rapidly, and then generates the bulk increasing motion, which makes the CNTs aggregates dispersed, and finally forms the CNTs gas-phase dispersion monomer with high dispersion or the cross-linking morphology of few CNTs. In this paper, the influence of gum Arabic (GA) and deionized water (DI water) contents in CNTs mixed electrode on the dispersion of CNTs in different environments (gas phase and liquid phase) is explored. In the limited case of this work, the dispersion effect is better when the mass ratio of CNTs, GA and DI water is 1:0.04:3.96 in the liquid-phase environment. The preparation method reported in this work is expected to be a rapid way to obtain low-concentration nanodispersion.
        4,000원
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