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        검색결과 58

        1.
        2024.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study aimed to investigate the impact of varying levels of neutral detergent-soluble fiber (NDSF) in Hanwoo growing cattle diets on rumen fermentation and methane (CH4) emissions. An in vitro rumen fermentation experiment utilized feeds with different NDSF levels, incorporating ingredients such as corn grain, soybean meal, soybean hulls, palm kernel meal, beet pulp and timothy hay. The NDSF contents in the diets were 9.02% (T1), 10.09% (T2), 12.42% (T3) and 14.63% (T4). In vitro dry matter digestibility (IVDMD) at 48 h was 7.4% higher for T4 compared to T1 (p<0.05). Total gas production at 48 h was 6.6% higher for T4 than T1 (p<0.05). CH4 production significantly decreased at 9 h and 12 h for T1 and T2 (p<0.05). At 48 h, CH4 production was 5.6% higher for T4 compared to T1 and 6.7% higher compared to T2 (p<0.05). At 12 h ans 24 h, the ammonia nitrogen concentration of T4 was approximately 33.1% and 40.4% lower, respectively, compared to T1 (p<0.05). The acetate to propionate ratio at 48 h was approximately 18.8% higher for T4 than T1 (p<0.05). From 9 h to 48 h, the proportions of butyrate and valerate were significantly higher for T4 (p<0.05). At 48 h, the dominant phylum in T4's rumen microbial community was Candidatus Thermoplasmatota Methanomassiliicoccus, an Archaea. Therefore, this study confirmed that increasing the NDSF content in growing Hanwoo cattle diets up to 12.42% increases IVDMD without increasing CH4 emissions, which is expected to positively impact Hanwoo productivity.
        4,300원
        3.
        2024.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1990년대 이후 급증한 탄소 배출량은 지구 온도 상승을 가속화하고 있으며, 도시는 온실가스 배출의 주요 원인으로서 약 70%의 배출량을 차지하고 있다. 이에 탄소중립 노력이 중요해지면서 도시 내 유일 한 탄소흡수원인 녹색공간의 효과적인 활용이 필수적이다. 본 연구는 탄소중립 녹색공간 평가를 위한 지표와 산정기준을 개발하기 위해 사례분석과 델파이 기법을 활용한 전문가 자문을 진행하였다. 그 결 과 총 45개의 평가지표가 구축되었으며, 5개 근린공원에 적용하여 지표의 적용 가능성을 검토하였다. 사례평가 결과 SCOPE 1, 2단계에 속하는 바이오매스 격리, 저탄소 공법 및 자재사용, 원형보존 유형이 탄소중립에 기여하는 정도가 높았으며, 탄소 특화공원이 일반 근린공원에 비해 강점을 보이는 것을 확 인하였다. 본 연구는 탄소중립 녹색공간 인증제 실현을 위한 도구를 제공하고 평가 프레임워크 구축에 중요한 기반 마련에 기여할 것으로 기대한다.
        4,000원
        4.
        2024.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the current research, a manganese and cobalt oxides-based nanocatalyst was developed which was used to make an efficient cathode electrode for fuel cells. The nano MnOx/ MnCo2O4 was synthesized through a hydrothermal procedure followed by sintering at 500–600 °C. X-ray diffraction and scanning electron microscopy besides electrochemical techniques were applied for the characterization of the synthesized nanocatalyst. The carbon black type Vulcan (XC-72R) and PTFE were used to prepare the active reaction material of the cathode electrode named carbon paste (CP). Loading of the synthesized nano MnOx/ MnCo2O4 on CP was optimized in a weight ratio of 10–90% for the oxygen reduction process in neutral conditions. The best performance was gained for the 50 W% MnOx/ MnCo2O4 loaded CP, whose active surface area was twice the bare CP. The values of the exchange current density of the ORR obtained by electrode containing 50 W% MnOx/ MnCo2O4 was calculated as 0.12 mA/cm2. The low price, good catalytic efficiency, and cyclic stability of the MnOx/ MnCo2O4 nanocatalyst compared to the commercial platinum-based catalysts confirm its ability to develop fuel cell electrodes.
        4,000원
        6.
        2023.10 구독 인증기관·개인회원 무료
        기후변화 위기에 대응하기 위하여 대한민국은 2030년까지 신재생연료 혼합비율(Renewable Fuel Standard, RFS)을 3.5%에서 8%까지 상향하기로 결정하였다. 국내에서 제조되는 신재생연료의 원료가 되는 바이오매스의 60%이상이 해외에서 수입하는 실정이며, 2030 탄소중립 및 RE100과 같은 바이오연료 사용증가 정책의 확대로 인하여 국내에서 제조되어 활용가능한 바이오매스의 확보가 절실하게 필요하다. 곤충은 높은 비율의 단백질과 지질을 체내에 저장하는 특징을 가지고 있으며, 곤충의 대량사육을 통하여 지질의 대량생산이 가능할 것으로 판단된다. 본 연구에서는 곤충의 대량사육환경에서 제조되는 지질을 원료로 하여 기후변화에 대응할 수 있는 바이오연료로의 전환 제조가능성을 확인하고자 하였으며, 이를 위하여 촉매공정을 통하여 디젤과 혼합하여 사용할 수 있는 수첨바이오디젤을 제조하여 그 특성을 분석하였다. 그 결과 곤충지질을 활용하여 수첨바이오디 젤로 전환가능함을 확인하였다.
        9.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 탄소 흐름 관점에서 기존 농촌경관 시스템 구조를 분석하고 이를 토대로 탄소중립 농촌경 관으로 전환하기 위한 자연기반해법을 제시하였다. 농촌경관 시스템은 생산경관, 자연경관, 생활경 관 하위 시스템으로 구성되어 있었으며, 각 하위 시스템을 인과지도 작성하고 이를 통합하였다. 통합 인과지도를 분석한 결과, 토지 이용 및 인간 활동 관리와 피드백 루프의 재구축을 위한 자연기반해법 전략이 필요하다는 것을 확인하였다. 이를 기반으로 본 연구는 ‘토양유기탄소 보존을 위한 탄소 농 업’, ‘탄소 흡수원 경관 관리’, ‘기후스마트 농업’, 그리고 ‘신재생에너지 기반 순환 농업’을 제안하였 다. 본 연구 결과는 기존 생산과정 중심의 농촌지역의 탄소중립 정책에서 벗어나 농촌경관 시스템의 전반적인 탄소 흐름을 확인하여 자연기반해법을 제시하였다는 데에 의의가 있다.
        4,300원
        10.
        2023.05 구독 인증기관·개인회원 무료
        The bioreduction process from soluble U(VI) to insoluble U(IV) has been extensively studied in the field of radionuclides migration. Since acetic acid (AcOH) is widely used as an electron donor for bioreduction of U(VI), it is necessary to understand the effect of U(VI)-AcOH complexes that exist in different species depending on pH on this process. Changes in samples before and after bioreduction can be compared using time-resolved laser luminescence spectroscopy (TRLLS), which measures the characteristic luminescence spectra of different U(VI) species. Although luminescence properties of U(VI)-AcOH species were reported, experiments were conducted under conditions below pH 4.5. In this study, spectrophotometry and TRLLS for U(VI)-AcOH species (10−100 μM U(VI) and 20 mM AcOH) were performed in pH ranges extending to neutral and alkaline pH regions similar to groundwater conditions as well as acidic pH region. Two different complexes (UO2(AcO)+, UO2(AcO)2 with U(VI) and acetate ratios of 1:1, 1:2) were observed in the acidic pH region. The 1:1 complex, which appears as the pH increases, has no luminescence properties, but its presence can be confirmed because it serves to reduce the luminescence intensity of UO2 2+. In contrast, the 1:2 complex exhibits distinct luminescence properties that distinguish it from UO2 2+. The 1:3 complex (UO2(AcO)3 -) expected to appear with increasing pH was not observed. Two different complexes ((UO2)3(OH)5 +, (UO2)3(OH)7 - with U(VI) and OH ratios of 3:5, 3:7) were observed as the major species in the neutral pH region, but their luminescence lifetimes are remarkably short compared those in the absence of AcOH. Solid U(VI) particles were observed in the alkaline pH region, and they also had completely different luminescence properties from the aforementioned U(VI)-AcOH and U(VI)-hydrolysis species. Based on these results, the effect of pH in the presence of AcOH on the bioreduction process from U(VI) to U(IV) will be discussed.
        12.
        2023.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Spin-off pyroprocessing technology and inert anode materials to replace the conventional carbon-based smelting process for critical materials were introduced. Efforts to select inert anode materials through numerical analysis and selected experimental results were devised for the high-throughput reduction of oxide feedstocks. The electrochemical properties of the inert anode material were evaluated, and stable electrolysis behavior and CaCu generation were observed during molten salt recycling. Thereafter, CuTi was prepared by reacting rutile (TiO2) with CaCu in a Ti crucible. The formation of CuTi was confirmed when the concentration of CaO in the molten salt was controlled at 7.5mol%. A laboratory-scale electrorefining study was conducted using CuTi(Zr, Hf) alloys as the anodes, with a Ti electrodeposit conforming to the ASTM B299 standard recovered using a pilot-scale electrorefining device.
        4,600원
        13.
        2022.10 구독 인증기관·개인회원 무료
        With respect to the geologic repository, intrusion of groundwater has been considered as a major factor that can transfer radionuclides to the natural environment. Moreover, the migration of radionuclides in the natural groundwater system is significantly influenced by the interaction between the radionuclides and groundwater constituents. Among various hydrogeochemical reactions, hydrolysis is one of the major reactions that can affect the aqueous solubility of radionuclides. Therefore, a precise understanding of relevant chemical thermodynamic behavior is of cardinal importance for the reliable prediction of migration/retardation behavior of radionuclides in the natural groundwater system. The objective of the present work is to investigate the solubility behavior of Nd(OH)3(s) to provide relevant chemical thermodynamic data of Nd(III) as a chemical analogy of major radiotoxic elements such as Am(III) and Cm(III). All the experiments were performed with Ar gas-filled glovebox under inert atmospheric condition. The aqueous Nd(III) solution was prepared by dissolution of 0.5 g NdCl3·6H2O (Sigma-Aldrich) in 10 ml of deionized water. The Nd(III) solid phase was precipitated by dropwise addition of ca. 10 ml of 4 M NaOH (Sigma-Aldrich). The Nd(III) precipitate was identified to be crystalline Nd(OH)3(s) nanorod by using XRD and TEM. For the solubility experiment, the solid Nd(OH)3(s) was equilibrated at the pH range from 5.0 to 9.0 at 0.1 M NaCl condition. The total concentration of the Nd(III) was quantified by using UV/Vis absorption spectroscopy and ICP-MS after the phase separation. In the present work, the solubility behavior of the solid Nd(OH)3(s) phase was investigated by using colorimetric analysis. The chemical thermodynamic data obtained in this study are expected to enhance the reliability of solubility prediction for the trivalent lanthanides and actinides.
        17.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고슬’은 농촌진흥청 국립식량과학원 고령지농업연구소에서 2016년도 육성한 중일성 딸기 신품종이다. ‘고슬’은 ‘Albion’을 모본으로 하고 ‘설향’을 부본으로 2012년 교배하여, 고온장일조건에서 과실이 크고 화방이 연속적으로 출현되는 우수한 중일성 개체를 선발한 것이다. 대관령의 가을재배 작형에서 2015년부터 2016년까지 생산력 및 특성검정을 거쳐 ‘새봉 9호’로 계통명을 부여하고, 지역적응성 시험을 거쳐 ‘고슬’로 명명하였다. ‘고슬’의 초형은 개장형이며, 엽형은 둥근형이며, 초세는 중간이다. 과실모양은 원추형이며, 과색은 붉은색이다. ‘고슬’의 화방수는 2.5개로 ‘Redpearl’보다 1.5개 더 많았다. ‘고슬’의 경도는 31.6 g·mm-2으로 매우 단단하였다. 또한 수확기간 2개월 동안 8.4개의 상품과일이 수확되었다. 가을에 수확된 ’고슬‘의 상품수량은 19,580 kg·ha-1로 경제적 재배가 가능하였다. 신품종 딸기 ‘고슬’은 고온에서도 화방이 잘 발생하고 착과되어 우리나라 고랭지 및 동남아 고원지대에서 재배가 가능한 중일성 딸기 품종이다.
        4,000원
        18.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Background: Measurement of passive ankle dorsiflexion range of motion (ADROM) is often part of a physical therapy assessment. Objects: The objective of this study was to identify the effects of subtalar joint neutral position (SJNP) on passive ADROM according to knee position in young adults. Methods: We recruited 14 young adult participants for this study. Two examiners used a universal goniometer to measure passive ADROM with and without SJNP. Dorsiflexion force was applied to the forefoot until maximum resistance was reached in two knee positions (extension and 90˚ flexion) in the prone position. Subtalar joint position was also recorded at maximum ADROM. Passive ADROM was measured three times at different knee and subtalar joint positions, in random order. Two-way repeated-measures analysis of variance was used to compare the effects of subtalar joint and knee position on passive ADROM. Results: Passive ADROM was significantly lower with than without SJNP during both knee extension (mean difference: 7.4˚) and 90˚ flexion (mean difference: 16.9˚) (p<.01). Passive ADROM was significantly higher during 90˚ knee flexion than during knee extension both with (mean difference: 5.8˚) and without SJNP (mean difference: 15.2˚) (p<.01). The valgus position of the subtalar joint was significantly lower with than without SJNP during both knee extension (mean difference: 3.3˚) and 90˚ flexion (mean difference: 4.3˚) (p<.01). Conclusion: Our results indicate that the gastrocnemius may limit ankle dorsiflexion more than the soleus does. Greater dorsiflexion at the subtalar and midtarsal joints was observed during passive ADROM measurement without than that with SJNP; therefore, SJNP should be maintained for accurate measurement of ADROM.
        4,000원
        19.
        2018.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Hydrogen evolution on a steel surface and subsequent hydrogen diffusion into the steel matrix are evaluated using an electrochemical permeation test with no applied cathodic current on the hydrogen charging side. In particular, cyclic operation in the permeation test is also conducted to clarify the corrosion-induced hydrogen evolution behavior. In contrast to the conventional perception that the cathodic reduction reaction on the steel in neutral aqueous environments is an oxygen reduction reaction, this study demonstrates that atomic hydrogen may be generated on the steel surface by the corrosion reaction, even in a neutral environment. Although a much lower permeation current density and significant slower diffusion kinetics of hydrogen are observed compared to the results measured in acidic environments, they contribute to the increase in the embrittlement index. This study suggests that the research on hydrogen embrittlement in ultra-strong steels should be approached from the viewpoint of corrosion reactions on the steel surface and subsequent hydrogen evolution/diffusion behavior.
        4,000원
        20.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to explore the effects of mobilization of C0-C1 and C7-T1 applied to asymptomatic individuals with reduced upper cervical rotation during the FRT. Design: parallel randomized controlled trial. 48 subjects(38.52 years±15.13) with C1-C2 rotation hypomobility in TFR joined the study and were randomized into three groups(C0, C7, control group). FRT in both directions was measured before and after the intervention. C0 intervention consisted of a dorsal translatoric mobilization of C0-C1 in the cervical neutral position. C7 intervention consisted of a ventral cranial translatoric mobilization of C7- T1 in neutral position and the control group maintained a supine position. C0 group experienced a FRT ROM to the restricted side increase of 17.64。(SD=4.55), that was significantly greater (P<0.001) than 5.95。 (SD=4.81) of the C7 group and 2.45。(SD=5.05) of the control group. The results showed that a dorsal translatoric mobilization of C0-C1 in neutral position restored the physiological FRT mobility in subjects with C1-C2 hypomobility and experienced statistical significant improvement in FRT as compared to a C7-T1 translatoric mobilization and a control group. (Level of evidence: 1b).
        4,000원
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