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        검색결과 32

        3.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        높은 안전성과 견고한 기계적 특성을 가진 고체상 슈퍼커패시터는 차세대 에너지 저장 장치로서 세계적 관심을 끌고 있다. 슈퍼커패시터의 전극으로서 경제적인 탄소 기반 전극이 많이 사용되는데 수계 전해질을 도입하는 경우 소수성 표 면을 가진 탄소 기반 전극과의 계면 상호성이 좋지 않아 저항이 증가한다. 이와 관련하여 본 연구에서는 전극 표면에 산소 플라즈마 처리를 하여 친수화된 전극과 수계 전해질 사이의 향상된 계면 성질을 기반으로 더 높은 전기화학적 성능을 얻는 방법을 제시한다. 풍부해진 산소 작용기들로 인한 표면 친수화 효과는 접촉각 측정을 통해 확인하였으며, 전력과 지속시간을 조절함으로써 친수화 정도를 손쉽게 조절할 수 있음을 확인하였다. 수계 전해질로 PVA/H3PO4 고체상 고분자 전해질막을 사 용하였으며 프레싱하여 전극에 도입하였다. 15 W의 낮은 전력으로 5초간 산소 플라즈마 처리를 시행하는 것이 최적 조건이 었으며 슈퍼커패시터의 에너지 밀도가 약 8% 증가하였다.
        4,000원
        4.
        2018.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We perform density functional theory calculations to study the CO and O2 adsorption chemistry of Pt@X core@shell bimetallic nanoparticles (X = Pd, Rh, Ru, Au, or Ag). To prevent CO-poisoning of Pt nanoparticles, we introduce a Pt@X core-shell nanoparticle model that is composed of exposed surface sites of Pt and facets of X alloying element. We find that Pt@Pd, Pt@Rh, Pt@Ru, and Pt@Ag nanoparticles spatially bind CO and O2, separately, on Pt and X, respectively. Particularly, Pt@Ag nanoparticles show the most well-balanced CO and O2 binding energy values, which are required for facile CO oxidation. On the other hand, the O2 binding energies of Pt@Pd, Pt@Ru, and Pt@Rh nanoparticles are too strong to catalyze further CO oxidation because of the strong oxygen affinity of Pd, Ru, and Rh. The Au shell of Pt@Au nanoparticles preferentially bond CO rather than O2. From a catalysis design perspective, we believe that Pt@Ag is a better-performing Ptbased CO-tolerant CO oxidation catalyst.
        4,000원
        5.
        2018.05 구독 인증기관·개인회원 무료
        SiHCl3를 제조하는 공정에서 배출되는 클로로실란 혼합가스 중 수소의 재이용을 위하여 분리공정이 필수적이며, Pd계 분리막이 사용될 수 있다. 일반적인 Pd분리막의 경우 300°C 이하에서 수소 흡착에 의한 취성문제와 공존하는 불순물가스에 의한 손상문제가 있을 수 있다. 따라서 본 연구에서는 이를 해결하고자 Pd layer 위에 Ru을 무전해 도금하여 Pd/Ru 복합 분리막을 제조하였고 저온에서 수소 투과도 및 안정성을 평가한 결과 180°C에서 50일 동안 수소에 의한 취성이 발생하지 않았으며 1.8 m3m-2h-1의 안정적인 투과량을 나타내었고. 또한 5% HCl, 0.5% SiHCl3가 포함된 가스를 225°C의 온도에서 2 bar로 주입하였을 때 9 hr 동안 Pd/Ru 복합 분리막이 손상되지 않고 수소의 투과량이 2.0 m3m-2h-1 이상으로 유지됨을 확인하였다.
        6.
        2017.11 구독 인증기관·개인회원 무료
        The potential application of palladium-ruthenium composite membranes to the separation of hydrogen from chlorosilane gases in silicon-based industries was investigated. Ru/Pd/Al2O3/PSS membranes were prepared by electroless plating. Hydrogen permeation tests and temperature programmed desorption analysis revealed that the addition of a Ru over layer on Pd changed the hydrogen adsorption characteristics, resulting in improved stability of the membrane at low temperatures. The Ru/Pd/Al2 O3/PSS composite membrane had a stable hydrogen permeation flux of 1.8 m3m-2h-1 over a period of 1,200 h at 180°C without suffering hydrogen embrittlement. After exposure to impurities such as HCl and SiHCl3 , the hydrogen permeation flux of the Ru/Pd/Al2 O3/PSS composite membrane was stable over a period of 9h with feed pressure of 2.0 bar at 225°C.
        7.
        2017.03 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 전기화학발광 소재로 널리 이용되는 Ruthenium 착화합물을 함유한 전기화학발광 소자의 활 성층 제작시, 인쇄성 및 공정성을 향상시키기 위해 Poly(methyl methacrylate) (PMMA)를 첨가하였을 때, PMMA의 함유량이 전기화학발광소자의 발광층 내 이온들의 이동 현상에 미치는 영향에 대하여 살펴보았다. 이를 위해, Ruthenium 착화합물과 이온성 액체가 9:1 비율로 섞인 용질이 Acetonitrile에 20 mg/ml 농도로 녹여진 용액과 Dichloromethane에 PMMA가 25 mg/ml의 농도로 용해된 용액을 세 가지 (10:0.14, 10:1 그리고, 10:3) 중량비로 섞어 서 준비한 용액으로부터 발광층을 형성하여 전기화학발광소자를 제작하고, 소자의 전기적 특성을 평가하였다. 그 결 과, 발광층 내의 PMMA 함유량이 증가할수록 Ruthenium 착화합물 기반 전기화학발광소자의 구동 전압은 점차 증가 하였고, PMMA의 양이 줄어들면 순방향 전압하의 전류와 역방향 전압하의 전류 차에 따라 나타나는 이력곡선 (hysteresis)이 점차 사라지는 것을 확인할 수 있었다.
        4,000원
        8.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        자의성을 둘러싼 논의에는 중지의 동기가 중심이 되고 있다. 물론 어떠한 행위에도 동기는 있다. 그러나 동기는 다의적이다. 또 반드시 하나의 동기에 의하여 행위가 행해지는 것도 아니다. 문제는 여러 가지 다수의 동기 중에서 행위를 중지시킨 요인을 어떠한 기준으로 추출할 것인가이다. 자의성의 일상언어적 의미는 외부적으로 강제되지 않는다는 것이다. 그렇다면 자의성의 존부에 우선 문제가 되어야 할 것은 중지행위에로 행위자를 강제하는 사정이 있는지 여부이다. 다음으로 그러한 외부적 상황이 행위자의 인식을 통하여 중지행위를 강제했다고 판단되면 자의성이 부정되고, 강제하지 않았다고 판단되면 자의성이 긍정된다. 여기에서 사용되는 것이 외부적 상황이 「일반적으로」 행위계속을 저지하는 강제적 요소가 될 수 있는가 하는 척도이다. 예컨대 단순한 시간의 경과는 강제적 요소의 판단에 척도가 될 수 없다. 이점에서 시사적인 것이 우리 판례에서 말하는 사회통념이다. 즉 일상생활상의 경험칙이라는 일반적 기준이다. 중지행위에로 행위자를 강제할 수 있는 외부적 상황인가는 통상적인 경험표준에 의하여 객관적으로 판단된다. 우리 판례도 이러한 사회통념을 기준으로 하지만, 판례가 사용하는 객관적 기준은 추상적으로 강제될 수 있는 외부적 사정이 존재한다는 것만으로 자의성을 부정한다는 점에 문제가 있다. 자의가 아니라고 말하기 위해서는 ‘행위자 자신에게도’ 그 강제가 기능하였다고 판단되어야 한다. 유혈을 보고 놀랐다는 사정이나 피해자가 애원하는 사정뿐만 아니라 발각될 위험이 있는 사태라고 하더라도 반드시 자의성을 부정하는 사정이라고는 할 수 없다. 이러한 사정이 일반적으로 자의성을 부정한다고 판단하고 더 이상의 판단을 하지 않음으로써, 결과적으로 판례는 자의성을 거의 인정하지 않는다. 중지행위의 자의성을 부정하기 위해서는 통상적인 경험에 비추어 일반적으로 강제가 될 수 있는 성질을 가지고, 이에 더하여 추가로 실제로도 행위자 자신에게 어쩔 수 없었다고 평가되어야 한다. 중지행위의 자의성을 부정하기 위해서는 통상적인 경험에 비추어 일반적으로 강제가 될 수 있는 성질을 가지고, 이에 더하여 추가로 실제로도 행위자 자신에게 어쩔 수 없었다고 평가되어야 한다. 이렇게 볼 때 요사이 유행하는 자의성에 대한 유형화작업은 그것이 무엇을 위한 유형화인지 관점을 갖지 않은 단순한 유형화이다. 그 결과는 원칙적 부정을 위한 유형화가 되고 만다. 이는 받아들일 수 없다. 유형화작업의 시각은 예외적 부정(예외적 긍정)을 위한 유형화여야만 한다.
        8,000원
        9.
        2014.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Well-distributed ruthenium (Ru) nanoparticles decorated on porous carbon nanofibers (CNFs) were synthesized using an electrospinning method and a reduction method for use in high-performance elctrochemical capacitors. The formation mechanisms including structural, morphological, and chemical bonding properties are demonstrated by means of field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). To investigate the optimum amount of the Ru nanoparticles decorated on the porous CNFs, we controlled three different weight ratios (0 wt%, 20 wt%, and 40 wt%) of the Ru nanoparticles on the porous CNFs. For the case of 20 wt% Ru nanoparticles decorated on the porous CNFs, TEM results indicate that the Ru nanoparticles with ~2-4 nm size are uniformly distributed on the porous CNFs. In addition, 40 wt% Ru nanoparticles decorated on the porous CNFs exhibit agglomerated Ru nanoparticles, which causes low performance of electrodes in electrochemical capacitors. Thus, proper distribution of 20 wt% Ru nanoparticles decorated on the porous CNFs presents superior specific capacitance (~280.5 F/g at 10 mV/s) as compared to the 40 wt% Ru nanoparticles decorated on the porous CNFs and the only porous CNFs. This enhancement can be attributed to the synergistic effects of well-distributed Ru nanoparticles and porous CNF supports having high surface area.
        4,000원
        10.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ru films were successfully prepared by plasma-enhanced atomic layer deposition (PEALD) using and plasma. To optimize Ru PEALD process, the effect of growth temperature, plasma power and plasma time on the growth rate and preferred orientation of the deposited film was systemically investigated. At a growth temperature of and plasma power of 100W, the saturated growth rate of 0.038 nm/cycle was obtained on the flat /Si substrate when the and plasma time was 7 and 10 sec, respectively. When the growth temperature was decreased, however, an increased plasma time was required to obtain a saturated growth rate of 0.038 nm/cycle. Also, plasma power higher than 40 W was required to obtain a saturated growth rate of 0.038 nm/cycle even at a growth temperature of . However, (002) preferred orientation of Ru film was only observed at higher plasma power than 100W. Moreover, the saturation condition obtained on the flat /Si substrate resulted in poor step coverage of Ru on the trench pattern with an aspect ratio of 8:1, and longer plasma time improved the step coverage.
        4,000원
        11.
        2012.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        CoSi2 was formed through annealing of atomic layer deposition Co thin films. Co ALD was carried out using bis(N,N'-diisopropylacetamidinato) cobalt (Co(iPr-AMD)2) as a precursor and NH3 as a reactant; this reaction produced a highly conformal Co film with low resistivity (50 μΩcm). To prevent oxygen contamination, ex-situ sputtered Ti and in-situ ALD Ru were used as capping layers, and the silicide formation prepared by rapid thermal annealing (RTA) was used for comparison. Ru ALD was carried out with (Dimethylcyclopendienyl)(Ethylcyclopentadienyl) Ruthenium ((DMPD)(EtCp)Ru) and O2 as a precursor and reactant, respectively; the resulting material has good conformality of as much as 90% in structure of high aspect ratio. X-ray diffraction showed that CoSi2 was in a poly-crystalline state and formed at over 800˚C of annealing temperature for both cases. To investigate the as-deposited and annealed sample with each capping layer, high resolution scanning transmission electron microscopy (STEM) was employed with electron energy loss spectroscopy (EELS). After annealing, in the case of the Ti capping layer, CoSi2 about 40 nm thick was formed while the SiOx interlayer, which is the native oxide, became thinner due to oxygen scavenging property of Ti. Although Si diffusion toward the outside occurred in the Ru capping layer case, and the Ru layer was not as good as the sputtered Ti layer, in terms of the lack of scavenging oxygen, the Ru layer prepared by the ALD process, with high conformality, acted as a capping layer, resulting in the prevention of oxidation and the formation of CoSi2.
        4,000원
        12.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The autothermal reforming reaction of methane was investigated to produce hyd rogen with Ni/CeO2-ZrO2, Ni/Al2O3-MgO and Ni-Ru/Al2O3-MgO catalysts. Honeycomb metalli c monolith was applied in order to obtain high catalytic activity and stability in autothermal r eforming. The catalysts were characterized by XRD, BET and SEM. The influence of various catalysts on hydrogen production was studied for the feed ratio(O2/CH4, H2O/CH4). The O2/CH4 and H2O/CH4 ratio governed the methane conversion and temperature profile of reactor. Th e reactor temperature increased as the reaction shifted from endothermic to exothermic reactio n with increasing O2/CH4 ratio. Among the catalysts used in the experiment, the Ni-Ru/Al2O3-MgO catalyst showed the highest activity. The 60% of CH4 conversion was obtained, and th e reactor temperature was maintained 600℃ at the condition of GHSV=10000h-1 and feed ratio S/C/O=0.5/1/0.5.
        4,000원
        13.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nanosized Pt, Pt-Ru and Pt-CeO2 electrocatalysts supported on acid-treated carbon nanotube (CNT) were synthesized by microwave-assisted heating of polyol process using H2Cl6Pt·6H2O, RuCl3, CeCl3 precursors, respectively, and were characterized by XRD and TEM. And then the electrochemical activity of methanol oxidation for catalyst/CNT nanocomposite electrodes was investigated. The microwave assisted polyol process produced the nano-sized crystalline catalysts particles on CNT. The size of Pt supported on CNT was 7~12 nm but it decreased to 3~5 nm in which 10wt% sodium acetate was added as a stabilizer during the polyol process. This fine Pt catalyst particles resulted in a higher current density for Pt/CNT electrode. It was also found that 10 nm size of PtRu alloys were formed by polyol process and the onset potential decreased with Ru addition. Cyclic voltammetry analysis revealed that the Pt75Ru25/CNT electrode had the highest electrochemical activity owing to a higher ratio of the forward to reverse anodic peak current. And the chronoamperemetry test showed that Pt75Ru25 catalyst had a good catalyst stability. The activity of Pt was also found to be improved with the addition of CeO2.
        4,000원
        14.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This Hee Kyeong Ru, a kind of "Nu-Gak” in Gwangju is a high storied old government official building memorizes the recovery of Gwangju area reputation. Hee Kyeong Ru, literally means, delightful and happy occasions. This kind of the buildings were build for the receptions and the banquets for the high government officials in travelling areas to areas. It provided very high formality as compared to the buildings in the mountains. Nu-Gak buildings have a lot in common, since they had been constructed under the influence of the then time period and for the common reasons. Several records about Hee Kyeong Ru can be found in the old literatures, poetries, pictures and atlases. Also, we can see the shape of the building and the location through the mark in the old map. According to the historic materials, Nu-Gak buildingsof other old goveenment offices with Hee Kyeong Ru are similar to that of the size and construction. So we can draw the common points of the existing old official buildings and could assume the original form of Hee Kyeong Ru. In conclusion, we need to restore Hee Kyeng Ru as the historical meaningful building and use it as a representative cultural building in Gwangju.
        4,900원
        15.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Different oxidation treatments on CNTs using diluted 4.0 M H2SO4 solution at room temperature and or at 90℃ reflux conditions were investigated to elucidate the physical and chemical changes occurring on the treated CNTs, which might have significant effects on their performance as catalyst supports in PEM fuel cells. Raman spectroscopy, X-ray diffraction and transmission electron microscope analyses were made for the acid treated CNTs to determine the particle size and distribution of the CNT-supported Pt-Ru nanoparticles. These CNT-supported Pt-based nanoparticles were then employed as anode catalysts in PEMFC to investigate their catalytic activity and single-cell performance towards H2 oxidation. Based on PEMFC performance results, refluxed Pt-Ru/CNT catalysts prepared using CNTs treated at 90℃ for 0.5 h as anode have shown better catalytic activity and PEMFC polarization performance than those of the commercially available Pt-Ru/C catalyst from ETEK and other Pt-Ru/CNT catalysts developed using raw CNT, thus demonstrating the importance of acid treatment in improving and optimizing the surface properties of catalyst support.
        4,000원
        20.
        2006.04 구독 인증기관·개인회원 무료
        Ru-C nano-composite films were prepared by MOCVD, and their microstructures and their electrode properties for oxygen gas sensors were investigated. Deposited films contained Ru particles of 5-20 nm in diameter dispersed in amorphous C matrix. The AC conductivities associating to the interface charge transfer between Ru-C composite electrode and YSZ electrolyte were 100-1000 times higher than that of conventional paste-Pt electrodes. The emf values of the oxygen gas concentration cell constructed from the nano-composite electrodes and YSZ electrolyte showed the Nernstian theoretical values at low temperatures around 500 K. The response time of the concentration cell was 900 s at 500 K.
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