• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.55-55
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• 2011

질소 등을 GST225 상변화재료에 첨가시켜 비저항을 증가시킴으로서 PCRAM의 동작 전류를 감소시킨 연구가 선행된 바 있다. 본 연구에서는 GST225와 달리 고속 동작 특성을 갖는 것으로 널리 알려진 Ge-doped SbTe (GeST) 상변화 재료에 Carbon을 첨가하여 박막 특성을 연구하여 동작 전류 감소의 가능성을 타진하였다. 실험을 위한 박막 제작을 위해 2 inch size의 GeST 및 C doped GeST (C-GeST) single target을 이용하여 RF magnetron co-sputtering 하였다. 박막은 carbon이 첨가되지 않은 GeST와 carbon 첨가량이 늘어나는 순서로 C-GeST 1, C-GeST 2, C-GeST 3로 구성된다. 이 때 제작한 박막의 composition analysis를 위해 XRF/RBS/AES가 사용되었고 제작된 박막의 기본적인 특성평가를 위해 resistivity(${\rho}$)와 crystallzation temp.(Cx), surface morphology(AFM), x-ray diffraction pattern(XRD)를 측정하였다. 실험결과 GeST, C-GeST 1, C-GeST 2, C-GeST 3 박막의 Cx는 각각 209, 225, 233, $245^{\circ}C$로 측정되어 carbon 첨가량이 증가됨에 따라 결정화 온도가 증가되는 것을 알 수 있었다. 또한 ${\rho}$도 마찬가지로 annealing 온도를 약 $320^{\circ}C$로 할 경우 ${\rho}$(as-dep)와 ${\rho}$(crystalline) 모두 0.03 / $2.61*10^{-6}$, 0.08 / $7.93*10^{-6}$, 0.09 / $11.99*10^{-6}$, 0.13 / $13.49*10^{-6}{\Omega}{\cdot}m$로 증가하였다. 증가된 ${\rho}$의 원인이 박막의 grain size의 감소라고 단언 할 수는 없으나 AFM 측정결과 grain이라고 추측되는 박막 feature들의 size가 점차 감소하는 것을 확인하였다.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.1
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• pp.58-67
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• 2008

Seasonal variations in carbon dioxide in the air and soil organic carbon in the sediments were monitored at the constructed wetland formed by reclamation work at Goheung Bay. Sediment sampling in the constructed wetland and carbon dioxide measurement in the air were conducted on June 16 and August 23, 2007. Sediments in the constructed wetland were sampled at 11 different points (June 16) and 14 points (August 23), while carbon dioxide in the air was measured at 13 points (June 16) and 15 points (August 23). Water content and organic carbon in the sampled sediments were analyzed in the laboratory. Water content of the sediments was higher than that of general soil, and the variation between June and August was not evident. The amounts of organic carbons in the sediments sampled on August 23 were higher than those sampled on June 16. Also, there was more organic carbon in the sediments sampled at the field of reeds than in the pure wetland area. Daily maximum variation in carbon dioxide in the air was higher on June 16, but the amount of carbon dioxide in the air was greater on August 23. The results of the study suggest that organic carbon in the sediments and carbon dioxide in the air were greater in summer (August 23) than in spring season (June 16) in the constructed wetland at Goheung Bay.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.2
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• pp.88-94
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• 2015

The KOTRON-13 cyclotron was manufactured by Samyoung Unitech as the second generation of the KIRAMS-13 cyclotron after its technology was transferred from the Korea Institute of Radiological and Medical Sciences in South Korea. Its prototype was installed at Seoul National University Bundang Hospital as part of a distributed network of regional cyclotrons with the support of a grant from the National Research Foundation of Korea. However, its initial condition has limited capacity to extract a relatively low beam current and to produce carbon-11. In this review, we provide an introduction and overview of the current state of the KOTRON-13 cyclotron, which was successfully upgraded by carrying out various modifications and optimizing the carbon-11 target system.

• Mass Spectrometry Letters
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• v.13 no.4
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• pp.139-145
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• 2022

Protein glycosylation is a common post-translational modification by non-template-based biosynthesis. In fungal biotechnology, which has great applications in pharmaceuticals and industries, the importance of research on fungal glycoproteins and glycans is accelerating. In particular, the importance of quantitative analysis of fungal glycans is emerging in research on the production of filamentous fungal proteins by genetic modification. Reliable mass spectrometry-based techniques for quantitative glycomics have evolved into chemical, enzymatic, and metabolic stable isotope labeling methods. In this study, we intend to expand quantitative glycomics by metabolic isotope labeling of glycans in Aspergillus niger, a filamentous fungus model, by the MILPIG method. We demonstrate that incubation of filamentous fungi in a culture medium with carbon-13 labeled glucose (1-¹³C₁) efficiently incorporates carbon-13 into N-linked glycans. In addition, for quantitative validation of this method, light and heavy glycans are mixed 1:1 to show the performance of quantitative analysis of various N-linked glycans simultaneously. We have successfully quantified fungal glycans by MILPIG and expect it to be widely applicable to glycan expression levels under various biological conditions in fungi.

• Advances in materials Research
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• v.13 no.3
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• pp.161-171
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• 2024

This study aimed to investigate the effect of physicochemical properties and mix ratios of iron ore (oxide feed): coke (reductant) on the carbothermic reductions of iron ore. Coke size was fixed at ≤63 ㎛ while iron ore size varied between 150-63 ㎛ and ≤63 ㎛ respectively. Mix ratios were changed from 100:0 (reference) to 80:20 and 60:40 while the temperature, heating rate and soaking duration in muffle furnace were fixed at 1100 ℃, 10 ℃/min and 1 hour. Particle size analyzer, XRF, CHNS and XRD analyses were used for determination of raw feed characteristics. The occurrence of phase transformations from various forms of iron oxides to iron during the carbothermal reductions were identified through XRD profiles and supported with weight loss (%). XRF analysis proved that iron ore is of high grade with 93.4% of Fe₂O₃ content. Other oxides present in minor amounts are 2% Al₂O₃ and 1.8% SiO₂ with negligible amounts of other compounds such as MnO, K₂O and CuO. Composite pellet with finer size iron particles (≤63 ㎛) and higher carbon content of 60:40 exhibited 45.13% weight lost compared to 32.30% and 3.88% respectively for 80:20 and 100:0 ratios. It is evident that reduction reactions can only occur with the presence of coke, the carbon supply. The small weight loss of 3.88% at 100:0 ratio occurs due to the removal of moisture and volatiles and oxidations of iron ore. Higher carbon supply at 60:40 leads into better heat and mass transfer and diffusivity during carbothermic reductions. Overall, finer particle size and higher carbon supply improves reactivity and gas-solid interactions resulting in increased reductions and phase transformations.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.3
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• pp.94-102
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• 2010

Carbon Neutral is one of the magnifying pan-governmental tasks which aim for stabilizing pan-global ecosystem. The purpose of this study is to estimates carbon neutral degree in cities by using capacity of carbon storage, which is carbon sinks, on forest and to develop an indicator that could be utilized in establishing policy related to climate change respond. When the carbon emitted from city has been absorbed or stored, the value of the indicator aiming to achieve carbon neutral could be drawn. The result and implication are as follows. First, while the annual amount of carbon emission in Gyeonggi S city was 18,787 thousand (tons), which was the highest, that of Gyeongbuk U city indicated the lowest with approximately 112 thousand (tons). Second, Gyeongbuk U city represented the largest capacity of annual carbon storage with about 16,748 thousand (tons), whereas the smallest figure was shown in Gyeonggi B city with 151 thousand (tons). Third, as result of the estimation of carbon neutral degree, the value of the indicator in Gyeonggi B city was 3% referring the lowest point, while that of other cities demonstrated over 100%. Forth, it has the possibility to suggest the fixed quantity when the plan for achieving carbon neutral of city is being processed. In the near future, after the completion of the construction projects of greenhouse gas inventory in all local governments, by utilizing the relative dates, the value of the indicator can be calculated and a more general conclusion could be drawn. Moreover, as expanding case studies to all domestic cities, generalness is in need.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.5
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• pp.7-13
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• 2006

This study was to evaluate the effect of carbon content on metallic change and fatigue characteristics with Fe-29%Ni-17%Co, low heat expansion alloy, widely using electronic components, precision machines, and sealing with glass and metal etc. The steels were fabricated with variation of carbon content, 0, 0.03, 0.06, 0.1, and 0.20% with VIM and tensile test and fatigue test were performed to achieve the above purpose. The more carbon content, the higher hardness value and yield strength. But elongation of 0.03%C, 0.06%C, and 0.10%C specimen decreased about 2.2%, 1.5% and 0.8% respectively more than that of the base metal. Especially the strength and elongation of 0.20%C specimen increased simultaneously about 14.4% and 7.5%. Fatigue life of 0.03%C specimen decreased but the more carbon content, the higher fatigue life over 0.06% carbon content more than that of base metal.

• Journal of Hydrogen and New Energy
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• v.21 no.1
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• pp.72-79
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• 2010

This paper is studying the selective separation of methane and carbon dioxide which are the main ingredients of biogas. Adsorption performance of molecular sieve 13x for carbon dioxide seems to be reasonable. In this experiments carbon dioxide contains about 3~5 ppm of methane and it is impossible to obtain high purity carbon dioxide. Applying the low temperature technique, it is possible to separate methane and carbon dioxide from bio gas. PRO II simulation shows results a small change of liquefaction temperatures and no difference with the used thermodynamic models. Applying low temperature technique, It is possible to separate carbon dioxide and methane from biogas.

• Journal of environmental and Sanitary engineering
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• v.17 no.3
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• pp.52-59
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• 2002

Pilot-scale PSSBR(Phase Separated Sequencing Batch Reactor) was operated to evaluate requirement of external carbon sources(${\Delta}gCOD/{\Delta}gNO_3^{-}-N$) in denitrification. Methanol and fermented food waste were used as external carbon sources. Methanol and fermented food waste were fed to the anoxic state of first reactor and concentration were 50 and 40 mgCOD/L on the basis of concentration in reactor, respectively. In case that external carbon source was not used, average $NO_3^{-}-N$ concentration in effluent was 22.49 mg/L. When methanol and fermented food waste were fed, average $NO_3^{-}-N$ concentration in effluent were 10.13 mg/L and 6.3 mg/L, respectively and requirement of external carbon sources were 4.04 and 2.5 ${\Delta}gCOD/{\Delta}gNO_3^{-}-N$, respectively. Fermented food waste was better than methanol in denitrification efficiency. Therefore fermented food waste could be one of the excellent external carbon sources for nitrogen removal in biological nutrient removal process.

• Journal of Powder Materials
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• v.23 no.6
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• pp.420-425
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• 2016

N-doped carbon nanofibers as catalysts for oxygen-reduction reactions are synthesized using electrospinning and carbonization. Their morphologies, structures, chemical bonding states, and electrochemical performance are characterized. The optimized N-doped carbon nanofibers exhibit graphitization of carbon nanofibers and an increased nitrogen doping as well as a uniform network structure. In particular, the optimized N-doped carbon nanofibers show outstanding catalytic activity for oxygen-reduction reactions, such as a half-wave potential ($E_{1/2}$) of 0.43 V, kinetic limiting current density of $6.2mAcm^{-2}$, electron reduction pathways (n = 3.1), and excellent long-term stability after 2000 cycles, resulting in a lower $E_{1/2}$ potential degradation of 13 mV. The improvement in the electrochemical performance results from the synergistic effect of the graphitization of carbon nanofibers and the increased amount of nitrogen doping.