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        검색결과 2,791

        21.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since their initial development in 2012, triboelectric nanogenerators (TENGs) have gained popularity worldwide as a desired option for harnessing energy. The urgent demand for TENGs is attributed to their novel structural design, low cost, and use of large-scale materials. The output performance of a TENG depends on the surface charge density of the friction layers. Several recycled and biowaste materials have been explored as friction layers to enhance the output performance of TENGs. Natural and oceanic biomaterials have also been investigated as alternatives for improving the performance of TENG devices. Moreover, structural innovations have been made in TENGs to develop highly efficient devices. This review summarizes the recent developments in recycling and biowaste materials for TENG devices. The potential of natural and oceanic biowaste materials is also discussed. Finally, future outlooks for the structural developments in TENG devices are presented.
        4,000원
        22.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Purpose : To investigate the effect of the amount of astigmatism on distance and near vertical heterophoria in adults aged 20~40 years. Methods : Thirty subjects (31.25±10.21 years) were participated, and refraction was performed using I-Profilerplus and a phoropter, and horizontal heterophoria (HH) and vertical heterophoria (VH) teats were conducted at distance and near using a Torrington chart. Results : HH and VH were approximately 0.80 △ (p=0.001) and 0.20 △ (p=0.002) greater at near than at distance, respectively. Spherical refractive errors did not correlate with HH and VH at distance and near. There was no correlation between astigmatism and HH at either distance or near (p=0.141, p=0.318, respectively), but VH at distance and near was significantly correlated with astigmatism (both, p < 0.001), the amount of VH increased with increasing the amount of astigmatism. Conclusion : We found that the amount of astigmatism affected the VH at both distance and near and that the amount of VH increased with increasing astigmatism. These findings suggest that it is important to assess both astigmatism and VH in clinical practice, and that correction of astigmatism may help to reduce symptoms of VH. Key words : Astigmatism, Horizontal heterophoria, Refractive error, Vertical heterophoria
        4,000원
        23.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        프리지아 ‘Ruby Star’는 농촌진흥청 국립원예특작과학원 에서 보라색 홑꽃 ‘Avilla’와 흰색 반겹꽃 ‘Medeo’를 2012년 교배하여 얻은 종자로부터 2006년 향이 좋고 개화기가 빠른 적색 홑꽃 계통을 선발하여 품종으로 개발되었다. 2014년부 터 2017년까지 생육·개화 특성검정 및 육성계통평가회의 기 호도 평가를 거쳐 선발되었으며 2018년 직무육성품종심의회 를 통해 ‘Ruby Star’로 명명되어 2021년 신품종으로 등록되 었다. ‘Ruby Star’는 빨간색(RHS, R45A) 홑꽃인 절화용 프리 지아 품종으로 개화소요일수가 118.0일이며 초장이 120.5cm 로 대조품종 ‘Rapid Red’보다 약 28.7cm 더 길다. 주당 분 지수는 5.8개로 대조품종에 비해 수확량이 많고 첫번째 분지 의 길이가 32.0cm, 두께가 3.02mm로 절화 특성이 우수하 다. ‘Ruby Star’의 소화수 및 소화폭은 각각 14.8개, 6.3cm 로 소화수가 많은 중대형화이다. 절화수명은 약 8.4일이며 주 당 자구수는 3.8개, 평균 자구중은 2.9g이다. 전자코를 이용 한 PCA 분석 결과 PC1과 PC2의 설명력은 각각 97.9%, 1.8%로 전체 변이의 99.7%를 반영했으며 ‘Ruby Star’와 대 조품종 ‘Rapid Red’는 서로 다른 향기 패턴을 보였다. Radar plot 결과 총 6개의 MOS 센서에서 ‘Ruby Star’의 센서 반응 이 ‘Rapid Red’보다 강하게 나타나 ‘Ruby Star’의 향기가 더 강한 것으로 나타났다.
        4,000원
        24.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        백합 종간 교잡종은 다양한 교배 방법에 의해 생산되어지 고 있다. 그러나 이들 종간 교잡종은 대부분 불임이다. 2n gametes는 백합에서 종간 교잡종 F1의 불임을 극복할 수 있 을 뿐 아니라 우수한 유전형질을 지닌 2n과의 교배에 이용할 수 있고 후대 다양한 유전형질을 기대할 수 있다. 따라서 본 실험에서는 가장 효과적으로 2n gametes를 생산할 수 있는 방법을 구축하기 위하여 백합 Oriental hybrids ‘Medusa’와 ‘Marco Polo’에 N2O를 처리하였다. 같은 Oriental 그룹 내 에서도 ‘Medusa’와 ‘Marco Polo’는 화뢰 크기별 감수분열 시기가 달랐다. 감수분열 tetrad 시기에 염색체를 관찰한 결 과 sequential spindles, tripolar spindles에 의해 2가지 다른 형태가 관찰되었다. ‘Medusa’에서 2atm의 N2O를 처리 한 화뢰 길이 10~15mm와 20~25mm에서 monad, dyad, triad, tetrad가 관찰되었다. 그러나 4atm에서는 tetrad 이외에는 검경 되지 않았다. ‘Marco polo’의 경우 화뢰 길 이 10~15mm, 25~30mm 시기에 2, 4atm의 N2O를 12, 24 시간 동안 처리한 구에서 모두 dyad, triad가 관찰되었다. ‘Medusa’, ‘Marco Polo’ 모두 dyad, triad, tetrad가 관찰 된 시기는 대조구에서 interphase와 metaphase Ⅰ에 해당 하는 시기이다. 화분의 모양은 타원형으로 처리 전·후 변화가 없었으며 처리 후 화분의 크기는 n 보다 큰 화분뿐 아니라 작 은 화분도 관찰되어 전체적으로 다양했다. 화분의 임성과 발 아율은 처리구별로 차이가 없었으나 평균적으로 처리 후가 무처리구보다 임성은 약 10%, 발아는 약 20% 정도 떨어졌다. ‘Medusa’와 ‘Marco Polo’를 이용하여 N2O를 처리한 것과 처리하지 않은 것을 정역 교배하였을 때 자방이 비대 되는 형 태가 2가지이었으나 처리 별 차이는 아니었다. 획득된 식물체 를 Flow cytometry로 검정한 결과, 무처리 ‘Marco Polo’와 2atm 24시간 32mm에 처리한 ‘Medusa’의 교배를 통해 하 나의 식물체에서 2배체와 3배체가 모두 나오는 mixoploid를 확인할 수 있었다. 그 외 실험을 통해 얻은 식물체 중에서 이 수체가 4개 발견되었다. 확실한 3배체를 가진 식물체는 관찰 할 수 없었다.
        4,500원
        25.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Emojis and avatars are widely used in online communications, but their emotional conveyance lacks research. This study aims to contribute to the field of emotional expression in computer-mediated communication (CMC) by exploring the effectiveness of emotion recognition, the intensity of perceived emotions, and the perceived preferences for emojis and avatars as emotional expression tools. The following were used as stimuli: 12 photographs from the Yonsei-Face database, 12 Memojis that reflected the photographs, and 6 iOS emojis. The results of this study indicate that emojis outperformed other forms of emotional expression in terms of conveying emotions, intensity, and preference. Indeed, the study findings confirm that emojis remain the dominant form of emotional signals in CMC. In contrast, the study revealed that Memojis were inadequate as an expressive emotional cue. Participants did not perceive Memojis to effectively convey emotions compared with other forms of expression, such as emojis or real human faces. This suggests room for improvement in the design and implementation of Memojis to enhance their effectiveness in accurately conveying intended emotions. Addressing the limitations of Memojis and exploring ways to optimize their emotional expressiveness necessitate further research and development in avatar design.
        4,000원
        26.
        2023.12 구독 인증기관 무료, 개인회원 유료
        The rack cylinder is an important part of the pile leg structure of the jack up platform. Because of its complex structure, the flow field around the rack cylinder is different from that around the ordinary cylinder, which brings difficulties to the research of the rack cylinder. In this paper, using CFD(Computational Fluid Dynamics) solved the flow field of chords with different rack height and rack width under different KC and Re, the characteristics of the flow field around the cylinder with rack are obtained. The results show that Re, KC, rack height and rack width all have different effects on the flow field. When Re and KC are constant, Cd will increase with the increase of rack height ratio, the change of Cd and Cl is not significant, while the change of Cd and Cl varies with Re when the chord structure is fixed.
        4,000원
        27.
        2023.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Single-atom Pd clusters anchored on t-BaTiO3 material was synthesized using hydrothermal and ultrasonic methods for the effective piezoelectric catalytic degradation of pollutants using vibration energy. XRD patterns of BaTiO3 loaded with monoatomic Pd were obtained before and after calcining, and showed typical cubic-phase BTO. TEM and HAADF-STEM images indicated single-atom Pd clusters were successfully introduced into the BaTiO3. The piezoelectric current density of the prepared Pd-BaTiO3 binary composite was significantly higher than that of the pristine BaTiO3. Under mechanical vibration, the nanomaterial exhibited a tetracycline decomposition rate of ~95 % within 7 h, which is much higher than the degradation rate of 56.7 % observed with pure BaTiO3. Many of the piezo-induced electrons escaped to the Pd-doped BaTiO3 interface because of Pd’s excellent conductivity. Single-atom Pd clusters help promote the separation of the piezo-induced electrons, thereby achieving synergistic catalysis. This work demonstrates the feasibility of combining ultrasonic technology with the piezoelectric effect and provides a promising strategy for the development of ultrasonic and piezoelectric materials.
        4,200원
        28.
        2023.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The legal status of Biodiversity Beyond National Jurisdiction (BBNJ) has been regulated through the High Seas Treaty as a common heritage of humankind. However, there still exist problems related to overlapping areas above the Extended Continental Shelf (ECS). In such areas, a significant continental shelf would fall within national jurisdiction, whereas the water column would be under the regime of the high seas, and BBNJ would be the common heritage of humankind. We argue that, in order to address the overlapping of areas within the superjacent waters in the ECS, a given sui generis status is required, so that the coastal state has a sovereign right to conserve the BBNJ in these areas. This study concludes that the sui generis arrangement should be implemented in the context of an overlapping ECS and its water column. The efforts of the Indonesian government to extend the continental shelf beyond 200 nautical miles constitute an important step in preserving natural resources for future generations.
        5,200원
        38.
        2023.11 구독 인증기관·개인회원 무료
        This study explores the impact of metal doping on the surface structure of spent nuclear fuels (SNFs), particularly uranium dioxide (UO2). SNFs undergo significant microstructural changes during irradiation, affecting their physical and chemical properties. Certain elements, including actinides and lanthanides, can integrate into the UO2 lattice, leading to non-stoichiometry based on their oxidation state and environmental conditions. These modifications are closely linked to phenomena like corrosion and oxidation of UO2, making it essential to thoroughly characterize SNFs influenced by specific element doping for disposal or interim storage decisions. The research employs X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy to investigate the surface structure of UO2 samples doped with elements such as Nd3+, Gd3+, Zr4+, Th4+, and ε-particles (Mo, Ru, Pd). To manufacture these samples, UO2 powders are mixed and pelletized with the respective dopant oxide powders. The resulting pellet samples are sintered under specific conditions. The XRD analysis reveals that the lattice parameters of (U,Nd)O2, (U,Gd)O2, (U,Zr)O2, and (U,Th)O2 linearly vary with increasing doping levels, suggesting the formation of solid solutions. SEM images show that the grain size decreases with higher doping levels in (U,Gd)O2, (U,Nd)O2, and (U,Zr)O2, while the change is less pronounced in (U,Th)O2. Raman spectroscopy uncovers that U0.9Gd0.1O2-x and U0.9Nd0.1O2-x exhibit defect structures related to oxygen vacancies, induced by trivalent elements replacing U4+, distorting the UO2 lattice. In contrast, U0.9Zr0.1O2 shows no oxygen vacancy-related defects but features a distinct peak, likely indicating the formation of a ZrO8-type complex within the UO2 lattice. ε-Particle doped uranium dioxide shows minimal deviations in surface properties compared to pure UO2. This structural characterization of metal-doped and ε-particle-doped UO2 enhances our understanding of spent nuclear fuel behavior, with implications for the characterization of radioactive materials. This research provides valuable insights into how specific element doping affects the properties of SNFs, which is crucial for managing and disposing of these materials safely.
        39.
        2023.11 구독 인증기관·개인회원 무료
        Heavy water (deuterium oxide, D2O) is water in which hydrogen atoms (1H, H), one of the constituent elements of water molecules, have been replaced with deuterium (2H, D), a heavier isotope. Heavy water is used in a variety of industries, including semiconductors, nuclear magnetic resonance, infrared spectroscopy, neutron deceleration, neutrino detection, metabolic rate studies, neutron capture therapy, and the production of radioactive materials such as plutonium and tritium. In particular, heavy water is used as a neutron moderator or coolant in nuclear reactors and as a fuel for nuclear fusion energy, methods for measuring heavy water are becoming increasingly important. There are methods with density, mass spectrometry, and infrared (IR) spectroscopy. In this study, Fourier transform infrared spectroscopy (FT-IR) was used, which is commonly used in IR spectroscopy because of its relatively high analytical sensitivity, low operating costs, and easy online analysis. Heavy water was identified in the range of 2,300-2,600 cm-1 wavenumber (O-D) and the range of 1,200-1,300 cm-1 wavenumber (D-O-D), which are known to be the range with strong infrared absorption. As a result, the linearity of infrared absorbance for each heavy water concentration was confirmed within the relative expansion uncertainty (k=2).
        40.
        2023.11 구독 인증기관·개인회원 무료
        Most of the C-14 produced is in the organic form, generated as methane (14CH4), methanol (14CH3OH), formaldehyde (14CH2O), and formic acid (14CO2H2). When analyzing C-14, it is transformed into the form of 14CO2, and its concentration is determined using LSC. Typical examples include the wet oxidation method, the combustion or Pyrolysis. The wet oxidation method uses strong acids and involves repeated operations, which generates large amounts of acid waste and secondary radioactive waste. The combustion method uses high temperatures, which requires an oxygen device. Pyrolysis also requires high temperature in a vacuum and catalysts. Catalysts are expensive because they are platinum-based. To compensate for these shortcomings, a C-14 analysis method using UV irradiation was developed. In this study, 100 mL of distilled water mixed with formic acid (CO2H2), potassium persulfate (K2S2O8), and silver nitrate (AgNO3) was irradiated with a 320-390 nm UV lamp to conduct a CO2 production reaction experiment. The UV range was measured using a photometer (UV Power puck II). The beaker was made of quartz in 150 mL size with three inlets : a temperature measurement, a sample inlet, and a collection tube connector. We changed the UV lamp used from a 450 W halogen lamp to a 100 W LED, which has a lower temperature and is safer. As a result of the experiment, CO2 bubbles were generated in the collection tube, due to the UV irradiation react, which uses oxidizer and catalysts. The maximum temperature of the solution irradiated with the LED UV lamp was less than 56°C. It confirmed the rate of bubble generation changed depending on the lamp distance, the amount of sample, oxidizer, and catalyst. In an experiment to confirm the reaction caused by heat, it was found that although a reaction occurred due to heat, the reaction was significantly lower than when using a UV lamp. The reproducibility experiment was conducted three times in total under the same conditions. It showed the same pattern. In the future, we plan to select mock samples, collect 14CO2 in Carbo- Sorb, and analyze them using LSC. The results of this research will be used as a technology to recover C-14 more safely and efficiently and will also be used to expand its application to the treatment of other wastes such as waste liquid and waste resin through simulated samples.
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