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        검색결과 173

        22.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        DLC has been attractive as semiconductor materials for solar cell due to its biological friendliness, flexible microstructures, and especially its tunable band gap. In order to fabricate high-efficiency multiband gap solar cell, it is important to control the sp3/ sp2 bonds ratio of DLC film corresponding to optical band gap (Eg). There are many references reporting the relations among the fabrication conditions, Eg, sp3/ sp2, and ID/ IG. However, a more comprehensive database is needed for controllable fabrication. Especially, the quantitative relationship of sp3/ sp2 ratio to Eg of DLC film by PECVD is unclear. In this paper, 36 sets of DLC films were fabricated by RF-PECVD. Characterization methods of XPS, Raman spectroscopy, and IR absorption have been used to determine the sp3/ sp2 ratio of DLC films. UV/visible light absorption method has applied to evaluate Eg. The Eg obtained is in the range 1.45–3.0 eV. Our results agree well with the references. The XPS spectra gives a linear relationship as Eg = − 0.161 (± 0.136) + 26.095 (± 1.704) · {sp3 (XPS)/sp2}, the Raman spectra shows a linear function that Eg = 1.327 (± 0.046) + 0.428 (± 0.036) · (ID/IG), as well as the FTIR analysis demonstrates that Eg = − 0.492 (± 0.093) + 0.464 (± 0.044) · {sp3 (FTIR)/sp2}.
        4,200원
        27.
        2020.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study investigates the role of age of first exposure in the acquisition and processing of English articles in an EFL setting. Fifty advanced Korean learners of English participated in a grammatical acceptability judgment task and a self-paced reading task. The participants were divided into two groups depending on the initial age at which they were constantly exposed to English at least 3 hours per week (‘early group’ < 12; ‘late group’ ≥ 12). No significant performance differences were observed between the two groups in the judgment task. However, meaningful differences were found between the reading behaviors of the two groups in the self-paced reading task. These findings show that the learners’ age of first exposure has a significant impact on learners’ performance when the ability to process English articles in real-time is evaluated. In contrast, it has much less impact on learners’ performance on a task which tests explicit knowledge under no time-limit condition.
        7,000원
        34.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Heteroatoms in situ-doped hierarchical porous hollow-activated carbons (HPHACs) have been prepared innovatively by pyrolyzation of setaria viridis combined with alkaline activation for the first time. The micro-morphology, pore structure, chemical compositions, and electrochemical properties are researched in detail. The obtained HPHACs are served as outstanding electrode materials in electrochemical energy storage ascribe to the particular hierarchical porous and hollow structure, and the precursor setaria viridis is advantage of eco-friendly as well as cost-effective. Electrochemical measurement results of the HPHACs electrodes exhibit not only high specific capacitance of 350 F g−1 at 0.2 A g−1, and impressive surface specific capacitance (Cs) of 49.9 μF cm−2, but also substantial rate capability of 68% retention (238 F g−1 at 10 A g−1) and good cycle stability with 99% retention over 5000 cycles at 5 A g−1 in 6 M KOH. Besides, the symmetrical supercapacitor device based on the HPHACs electrodes exhibits excellent energy density of 49.5 Wh kg−1 at power density of 175 W kg−1, but still maintains favorable energy density of 32.0 Wh kg−1 at current density of 1 A g−1 in 1-ethy-3-methylimidazolium tetrafluoroborate ( EMIMBF4) ionic liquid electrolyte, and the excellent cycle stability behaviour shows the nearly 97% ratio capacitance retention of the initial capacitance after 10,000 cycles at current density of 2 A g−1. Overall, the results indicate that HPHACs derived from setaria viridis have appealing electrochemical performances thus are promising electrode materials for supercapacitor devices and large-scale applications.
        4,600원
        36.
        2019.04 구독 인증기관·개인회원 무료
        방사선조사기술은 기존의 물리·화학적인 식물검역 방법의 대안 중의 하나로 여겨진다. 본 연구는 식물검역의 목적으로 1000 Gy 이하의 감마선 조사가 국내 주요 수출 농산물인 딸기의 이화학적, 관능적 품질 특성 및 유기성분 함량에 미치는 영향을 조사하는 것이었다. 감마선 조사는 딸기의 부패율과 중량손실률을 감소시켰으며, pH, 산도, 수분활성도, 가용성 고형분 함량 변화에는 영향을 미치지 않았다. 경도의 경우에도 조사 직후 유의적인 감소는 있었으나, 저장기간에 경과함에 따라 상쇄되었으며, 주요 페놀산 및 플라보노이드 함량 변화에 영향을 미치지 않았다. 반면, 감마선 조사는 딸기의 안토시아닌 생합성을 억제시켜 과일의 색도 변화를 지연시켰으며, 저장 9일째 비조사구보다 높은 관능적 선호도를 부여하였다. 결론적으로 딸기에 대한 1000 Gy 이하의 감마선 조사는 비조사구 대비 유익한 품질상승효과를 나타내는 것으로 관찰되었다.
        39.
        2018.11 구독 인증기관·개인회원 무료
        Mitochondrial and mitochondrial DNA (mtDNA) is maternally inherited in humans and most animals. The degradation of sperm-borne mitochondria after fertilization assures normal preimplantation embryo development and may prevent mitochondrial diseases derived from heteroplasmy. Although it has been known that ubiquitin-proteasome system (UPS) is the major degradation pathway of post-fertilization sperm mitochondria in mammals, it is unclear how the UPS, which is able to get rid of single protein molecule at a time, can eliminate whole sperm mitochondrial organelle. We considered that the autophagy receptors [sequestosome 1(SQSTM1), microtubule-associated protein 1 light chain 3 (LC3), and gamma-aminobutyric acid receptor-associated protein (GABARAP)] and the non-traditional mitophagy pathways involving UPS and the ubiquitin-binding protein dislocase, valosin-containing protein (VCP) may act independently or in concert during post-fertilization sperm mitophagy. We found that the association of SQSTM1 with sperm mitochondria was displayed in both pig and rhesus monkey zygotes after fertilization. Sperm mitochondrial proteins [mitochondrial trifunctional enzyme subunit alpha (HADHA), mitochondrial aconitase 2 (ACO2), and mitochondrial ATP synthase H+ transporting F1 complex β-subunit (ATP5B)] co-purified with the synthetic, SQSTM1-derived, ubiquitin-binding UBA domain were identified. Also, the accumulation of GABARAP-positive protein aggregates was observed around sperm mitochondrial sheaths in fertilized oocytes, which reflects autophagosome formation. Furthermore, the inhibition of VCP delayed the process of sperm mitophagy and completely blocked it when embryos were co-injected with autophagy-targeting antibodies, such as anti-SQSTM1 and/or anti-GABARAP. Thus, both SQSTM1-dependent autophagy pathway and VCP-mediated proteasomal proteolysis facilitate post-fertilization sperm mitophagy in mammals. This explains how the proteolytic pathway can coordinate autophagy pathway to degrade the sperm mitochondrial sheath inside the fertilized oocyte.
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