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        검색결과 7,467

        1.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 육묘기간과 PFAL 내 CO2 농도에 따른 참당귀의 지상부 및 지하부 생육, 광합성 색소 변화, 육묘기간을 평가하 는 것을 목적으로 하였다. 참당귀 종자는 72구 트레이에 파종 하였고 파종 후 40, 50, 및 60일차에 참당귀 묘의 형태학적 특 징과 엽록소 함량을 조사하였다. PFAL 내 온도는 22/19℃ (주간/야간)으로 유지되었고 광주기는 12시간이었다. CO2 농 도는 ambient (475 ± 40μmol∙mol-1), ‘high concentration’ (‘HC’, 758 ± 29μmol∙mol-1), 그리고 ‘very high concentration’ (‘VHC’, 1,197 ± 37μmol∙mol-1) 세 가지 수준으로 설정되었 다. CO2 공급은 자엽이 완전히 전개되고 본엽이 관측되는 파 종 후 20일차에 시작되었다. 파종 후 50일차부터 관부직경, 엽 면적, 뿌리발달, 그리고 건물중이 ambient에 비해 HC와 VHC 에서 높았으며 이는 생육속도가 빨랐음을 의미한다. 하지만 HC와 VHC 간에 건물중은 통계적으로 유의한 차이가 없었 다. 형태학적 관점에서 VHC는 파종 후 60일차에 엽병장이 길 고 엽면적이 넓어져 수평적 캐노피 확장이 이루어졌으며, 생 리적으로는 총 엽록소 함량이 감소하였다. 또한 ambient에 비 해 엽면적 지수가 높고 잎의 두께를 나타내는 지표인 비엽중 이 감소하였다. 이는 생장속도가 빨라져 협소한 플러그 트레 이 환경 내에서 개체 간 경쟁이 이루어진 결과로 판단된다. 따 라서 참당귀의 육묘기간을 단축시키기 위한 적정 CO2 농도는 약 800μmol∙mol-1로 판단되며, 적정 육묘기간은 50일로 사료 된다.
        4,000원
        2.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Though Farnesiferol C (FC) derived from Ferula asafoetida is known to have antiangiogenic and apoptotic effect in gastric, breast, nonsmall lung cancers, the underlying antitumor mechanism of FC is not fully understood so far. Hence, in the current study, apoptotic mechanism of FC was explored in colon cancers in association with carbon catabolite repression 4-negative on TATA-less 2 (CNOT2)/c-Myc signaling. Herein FC significantly increased cytotoxicity and reduced the number of colonies in HCT116 cells more effectively than in SW480 cells, though FC enhanced sub-G1 cell population in HCT116 and SW480 cells compared to untreated control. Consistently, FC activated the cleavages of Poly ADP-ribose polymerase (PARP) and Bax and attenuated the expression of pro-PARP and Cyclin D1 in HCT116 cells better than SW480 cells. Also, FC significantly reduced the expression of CNOT2 and c-Myc. Also, FC reduced of c-Myc stability in HCT116 cells by cycloheximide assay. Notably, CNOT2 depletion reduced the expression of c-Myc, while c-Myc depletion also attenuated the expression of CNOT2 in HCT116 cells, implying the crosstalk between CNOT2 and c-Myc. Furthermore, overexpression of c-Myc or CNOT2 promoted the expression of pro-PARP in HCT116 cells. Overall, these findings suggest that FC induces apoptosis via inhibition of CNOT2 and c-Myc in colon cancers for a potent anticancer candidate for further agriculture cultivation in Korea.
        4,000원
        3.
        2025.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The electric discharge experiment, known as the Miller-Urey experiment, is one of the experiments to understand the origin of life on Earth. The experiment involved simulating the Earth’s early atmosphere by introducing methane(CH4), ammonia(NH3), and nitrogen(N2) gases, and applying energy through electric discharge. Resulting solution was found to contain amino acids such as glycine(C2H5NO2), alanine( C3H7NO2), histidine(C6H9N3O2), proline(C5H9NO2), and valine(C5H11NO2). These amino acids were compared with the results of the recent experiment (Parker et al. 2014). Interestingly, the electric discharge produced C2 swan band and CN emission and it was newly found in gas phase. These two emission bands are commonly observed in comets.
        4,000원
        6.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본고는 미국 대외정책의 맥락에서 트럼프 2기 행정부의 AI 정책 방향 을 보다 체계적으로 조망해볼 필요가 있다는 문제의식에서 출발한다. 미 대통령이 정책 방향을 제시할 때 활용하는 대표적 수단은 연두교서와 대 통령 행정명령(Executive Order)이다. 특히 트럼프 1기 행정부 초반 3 년간 서명한 행정명령이 137건에 이를 정도로 트럼프 대통령은 행정명령 을 적극적으로 활용했다. 아울러 국가안보전략(NSS)과 같이, 대통령실 차원에서 발표되는 전략문서도 미 정부의 정책방향을 파악하는데 도움이 된다. 트럼프 1기 행정부 대통령 및 대통령실 차원에서의 AI 관련 내용 을 담은 문서로서는 우선 백악관 명의로 발표된 국가안보전략(2017.12.) 이 있다. 동 전략은 미국의 번영과 안보라는 측면에서 AI 이슈를 언급하 였다. 2019년 2월 발표된 연두교서에서 트럼프 대통령은 미래 첨단 산업 투자의 중요성을 역설하였다. 같은 달 트럼프 대통령은 AI 관련 행정명 령 제13859호를, 대통령실 과학기술정책실(OSTP)은 동 행정명령에 기초 해 “미국 AI 이니셔티브(American AI Initiative)”를 발표했다. 이후 2019년 6월 대통령실 산하 국가과학기술위원회는 “국가 AI R&D 전략계 획"을 발표했다. 이 일련의 문서들은 '미국 우선주의'에 기초하여, AI 분 야의 정책을 구체화해 나간다는 동일한 맥락 속에 있다. 상기 1기 트럼 프 행정부의 AI 정책 관련 문서를 검토한 본고의 논의는, 2기 트럼프 행 정부의 AI 정책을 조망하는데 함의를 제공한다.
        5,800원
        7.
        2025.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Eu-doped SrAl2O4 is a promising thermoluminescent and mechanoluminescent material with high brightness and stability, making it suitable for various luminescent devices. In this study, SrAl2O4:Eu was synthesized using a solid-state reaction method, and the effects of reducing atmosphere and high-temperature synthesis conditions on its luminescence properties were systematically analyzed. The luminescence characteristics of SrAl2O4:Eu were found to be highly sensitive to synthesis temperature, atmosphere, and Eu doping concentration, and optimal conditions were determined. A comparison of SrAl2O4:Eu synthesized at 1,300 °C under air and reducing atmospheres revealed that the reducing atmosphere plays a critical role in stabilizing Eu2+ ions, forming a single-phase SrAl2O4, and establishing luminescence centers. Notably, SrAl2O4:Eu synthesized at 1,600 °C in a reducing atmosphere achieved a photoluminescence quantum yield (PLQY) of 43 % and a maximum luminance of 2,030 Cd/m2, showing significant improvement in luminescence efficiency compared to samples synthesized at 1,300 °C. When Eu doping concentrations were adjusted from 1 % to 20 %, the highest luminescence performance was observed at 10 % doping, while excessive doping (20 %) increased non-radiative recombination pathways, and no further improvement in luminescence efficiency was observed. X-ray Diffraction (XRD) and Photoluminescence (PL) analyses elucidated the effects of synthesis conditions on the structural stability and luminescence properties of SrAl2O4:Eu, and the optimal reducing atmosphere and high-temperature synthesis conditions are proposed. This study provides a synthesis strategy for enhancing the luminescence properties of Eu-doped SrAl2O4 and lays the groundwork for the development of highperformance thermoluminescent and mechanoluminescent materials.
        4,000원
        8.
        2025.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study explored factors affecting variability in second language (L2) learning motivation among Korean university students and how they appraised their L2 learning experience. In this study, 85 undergraduate students majoring in English or English education from three universities in Seoul, South Korea, reflected on their past English learning experience. They drew a motigraph and wrote a retrospective reflection essay covering their English learning that spanned over ten years. Researchers divided participants into two groups: a high variability (HV) group and a low variability (LV) group. Data were analyzed using open, axial, and selective coding. Findings suggest thncontextual factors such as the learning method, atmosphere, and situation were main (de)motivational factors for the HV group. In contrast, the LV group was (de)motivated by intrapersonal factors, including the learning context appraisal. These results imply that visualizing long and short-term goals and positive appraisal of the L2 learning experience can help L2 learners maintain a stable pattern in L2 learning motivation.
        5,800원
        9.
        2025.03 구독 인증기관 무료, 개인회원 유료
        4,000원
        10.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 근시 어린이를 대상으로 2년 동안 OK-렌즈 착용자의 근시 감소에 대한 효능을 평가하고자 하였다. 방법 : OK-렌즈 그룹은 OK 렌즈 착용 기준에 부합하는 30명의 대상자로 구성되었고, 단초점 안경을 착용한 대조군에는 31명이 포함되었다. 이 연구에 사용된 OK-렌즈는 CRT였고, 굴절이상 측정은 조절마비제 사용없이 자 동굴절검사기와 자각적 굴절검사를 통하여 이루어졌다. 결과 : 총 61명(OK-렌즈 그룹과 대조군은 각각 30명, 31명)의 대상자가 2년 동안의 검사를 완료했다. 연구 초 기의 OK-렌즈군과 대조군의 평균 연령±SD는 각각 10.13±1.81세와 10.32±1.73세였고, 등가구면굴절력은 OK-렌즈군에서 –2.53±0.96 D, 대조군에서 -2.56±1.10 D로 두 그룹 간 유의미한 차이는 없었다. 2년 동안 등 가구면굴절력의 증가는 OK-렌즈군과 대조군에서 각각 –0.70±0.56 D, -1.27±0.78 D였으며, 그 차이는 통계적 으로 유의한 차이가 있었다(p<0.001). 결론 : OK-렌즈 치료는 학령기 어린이의 근시 진행을 늦추는 데 도움이 될 수 있다.
        4,000원
        11.
        2025.03 구독 인증기관 무료, 개인회원 유료
        초임계 이산화탄소 조건에서 다중벽 탄소 나노튜브(MWCNT)에 공유결합으로 조합된 폴리(2-에티닐피리디 늄 염) 복합체를 제조하였다. 초기 반응 단계에서 MWCNT 표면에서 형성된 4차염화 2-에티닐피리디늄 염의 활성 화된 아세틸렌 삼중 결합이 MWCNT 표면에서 연속적으로 중합되어 폴리(2-에티닐피리디늄 염)이 공유결합으로 조 합된 MWCNT가 용이하게 제조되었다. MWCNT/폴리(2-에티닐피리디늄 염)의 전기 광학 및 전기화학적 특성을 측 정하고 분석하였다. 해당 복합체의 광발광 피크는 2.04 eV의 광자 에너지에 해당하는 610 nm에서 관찰되었다. SnO2:F/TiO2/N719 염료/고체 전해질/Pt 장치가 있는 준고체 DSSC를 MWCNT/P2EP로 제조하였는데, 이의 최대 에 너지 변환효율은 5.33%였다.
        4,000원
        12.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzes research trends in mushrooms using social network analysis (SNA) and Word2Vec analysis based on 654 papers published in the journal of mushrooms. By tracking changes in research trends through centrality indices of key keywords and temporal keyword associations, it was found that in the early period (2011–2015), research primarily focused on optimizing growth conditions. During the mid-period (2016–2020), studies on strain characteristics and disease resistance became more prominent. In the recent period (2021–2024), research on molecular biology and functional components has expanded significantly, with molecular biology research, substrate and cultivation environment studies, and quality and functional food research emerging as new research areas. Meanwhile, research on Pleurotus ostreatus has been the most active, whereas studies on other mushroom species remain relatively limited, indicating the need for a broader scope in future research. This study provides an in-depth review of the research trends and transformations in the journal of mushrooms, contributing to the discussion on its balanced development and future research directions.
        4,200원
        13.
        2025.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        가위벌과에 속하는 Coelioxys의미기록 2종 Coelioxys conoidea Illiger, 1806 와 Coelioxys formosicola Strand, 1913을 한국에서 처음으로 보 고한다. 본 종의 기재, 분포정보, 그리고 삽화를 제공한다.
        4,000원
        14.
        2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon neutrality by 2050 was declared and are focusing on developing innovative energy technologies aimed at reducing greenhouse gas emissions. Active investment and research are underway in the full-cycle development of hydrogen energy technologies, including hydrogen production, storage, transportation, and utilization, which is gaining attention as a promising future eco-friendly energy source. The storage density of liquid hydrogen is 70.79kg/m3, which is higher than the 41kg/m3 of compressed hydrogen at 700bar, making it more suitable for large-scale storage. To store hydrogen at 20K, insulation technologies such as vacuum insulation, powder insulation, or multi-layer insulation (MLI) are typically required. Consequently, there is active research being conducted on the design of insulation systems and materials. However, research on the design for improving the structural integrity of the supports between the inner and outer tanks remains insufficient. n this study, topology optimization was performed for the support design of a liquid hydrogen storage tank using commercial finite element analysis (FEA) software. The structural safety was validated through structural analysis of a simplified self-designed model.
        4,000원
        15.
        2025.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Composites of carbon fiber-reinforced silicon carbide (Cf/SiC) with ultra-high temperature ceramics (UHTCs) exhibit superior resistance to oxidation and ablation under high temperatures. Components in large-scale applications often have complex geometries, making it crucial to understand the oxidation and ablation behaviors of curved and non-uniform surfaces. In this study, a Cf/SiC-ZrB2 composite was fabricated into a 300 mm cylindrical shape using filament winding and liquid silicon infiltration processes. The resulting specimens exhibited a uniform microstructure, with SiC and ZrB2 crystals evenly distributed across the top and bottom surfaces, demonstrating the feasibility of producing large-scale composites. The specimens underwent an oxyacetylene torch test at 2,100 K for 5 min to assess their ablation and oxidation performance. The results revealed significant variation in the oxide layer due to the non-flat surface, with the layer thickness gradually decreasing as the oblique angle was reduced. Additionally, the presence of high-melting-point ZrO2 in the oxide layer near the torch center was attributed to the migration and solidification of molten SiO2. This suggests that large and complex Cf/SiC incorporating UHTCs can effectively form a protective oxide layer, even under conditions where SiO2 displacement occurs. The findings underscore the importance of integrating geometric considerations into the design of ultra-high temperature ceramic composites to achieve the thermal and ablation resistance required for advanced high-temperature applications.
        4,000원
        16.
        2025.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigated the effect of band gap engineering on the thermoelectric properties of n-type Cu0.008Bi2Te3 using the two-band (TB) model. The experimental measurements showed a zT of ~0.41 at 300 K and ~0.46 at 520 K, with an optical band gap of ~0.13 eV. While fixing the density-of-state effective mass (md *), deformation potential (Edef), lattice thermal conductivity (κl), and Fermi level based fitted based on experimental data, we varied the band gap (Eg) from 0.1 to 0.3 eV to analyze its impact on the thermoelectric performance. The TB model calculations revealed that the power factor (PF) increased and the thermal conductivity (κ) decreased with increasing Eg at both 300 K and 520 K, leading to an enhancement in zT. The magnitude of this enhancement was more pronounced at 520 K than at 300 K, which can be attributed to the suppressed bipolar effects at higher temperatures. Our findings suggest that increasing the band gap of Cu0.008Bi2Te3 can significantly improve its thermoelectric performance, to an estimated maximum zT of ~0.61 at 520 K for Eg = 0.3 eV. The theoretical maximum zT, considering the optimized hole concentration (nH), was estimated to be ~0.75. We demonstrate that Eg engineering of narrowbandgap semiconductor thermoelectric materials can significantly enhance thermoelectric performance.
        4,200원
        17.
        2025.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        With increasing globalization and the urgent need for sustainable energy solutions, electrochemical water splitting has emerged as a crucial technology for clean energy production. In this study, we report the successful synthesis of 0.1 % Fe-doped NiS2 via a one-step hydrothermal method. The incorporation of Fe into the NiS2 matrix significantly enhances its electrochemical performance, as evidenced by a remarkable reduction in overpotential, to 180 mV at a current density of 10 mA cm-2, compared to 250 mV for undoped NiS2. Additionally, the Fe-doped NiS2 exhibits a reduced Tafel slope, high double layer capacitance, and lower charge transfer resistance than undoped NiS2, indicating improved reaction kinetics for oxygen evolution. These improvements are attributed to the enhanced conductivity and catalytic activity imparted by Fe doping, which facilitates more efficient charge transfer and reaction processes at the electrode surface. The results suggest that Fe-doped NiS2 is a highly promising and robust candidate for applications in electrochemical energy conversion. Moreover, the doping strategy employed here offers a valuable approach for tailoring the properties of other metal sulfides and chalcogenides, paving the way for the design of next generation electrocatalysts that can drive large-scale energy conversion processes with minimal energy loss.
        4,000원
        18.
        2025.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Globally, there is a concentrated effort to lead in alternative energy technologies. Among various eco-friendly energy sources and carbon-free fuels, hydrogen energy is gaining attention as a clean energy solution for future industries, as its only byproduct is water. There are two primary storage methods: compressing hydrogen gas at high pressure and storing it as a liquid. Research on insulation, including the structural design of multi-layer Insulation (MLI) and vapor-cooled shield (VCS), as well as the materials used for insulation, has been actively conducted. However, studies focused on improving the structural safety of the supports that sustain the structure between the inner and outer tanks have been limited. In this study, a thermal-structural coupled analysis technique for liquid hydrogen storage tanks was developed using commercial finite element analysis software for the design of support structures for liquid hydrogen storage tanks. Six analytical models were created based on varying the number and diameter of the supports with the constant total volume of the supports and a structurally safe support configuration was proposed.
        4,000원
        19.
        2025.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Over-the-scope clip (OTSC) 시스템은 위장관 질환에서 난치성 출혈, 천공, 그리고 누공을 봉합하기 위한 full-thickness 봉합 장치로 기존의 through-the-scope clip (TTSC)에 비해 더욱 강한 힘으로 조직을 움켜잡아 봉합할 수 있으며, 비교적 큰 결손을 보이는 천공도 봉합이 가능한 장점을 가지고 있다. 저자들은 괴사성 췌장염으로 발생한 대장 누공과 담도 내 삽입된 플라스틱 배액관의 이탈로 인한 십이지장 천공을 OTSC로 성공적으로 치료했던 증례를 소개하고자 한다.
        4,000원
        20.
        2024.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study analyzed actual traffic accident data to select humans’ unavoidable accidents and to examine whether avoidance is possible after AEBS(Advanced Emergency Braking System) is applied to these accidents. In cases where avoidance is not possible with AEBS, those accidents were determined to be examples where V2X(Vehicle-to-Everything) technology is necessary. Subsequently, by applying V2V(Vehicle-to-Vehicle) and V2I(Vehicle-to-Infrastructure) communication technologies, this research analyzed the possibility of accident avoidance. The results confirmed that the application of V2X technology enables accident avoidance. Additionally, by applying various variables, it identified limitation scenarios that cannot be resolved by V2X technology, and discussed strategies for accident avoidance in such situations.
        4,000원
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