Co- and N-doped carbon nanotubes with hierarchical pores derived from metal–organic nanotubes for oxygen reduction reaction (original) (raw)
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This study was performed to investigate laboratory workers' exposures to airborne nanoparticles at a university laboratory where acid treatment experiments were conducted on the surfaces of engineered carbon nanotubes (CNTs). The surface area concentrations, number concentrations, and mass concentrations of airborne nanoparticles were measured at personal breathing zones (PBZs) for various tasks using direct reading instruments. For all three metrics, airborne nanoparticle concentrations during the experiments were higher than background levels measured before and after the experiments for all three metrics. Among the various tasks that were performed as part of these experiments, one task that involved filtering a mixture of acid and CNTs showed the highest concentrations in all three metrics, with concentrations of /cc, 24320 pt/cc, and , respectively. Nanoparticle surface area concentrations measured at a representative area fluctuated with those at the PBZs in the laboratory...
1P-429: Carbon Quantum Dots for Photocatalytic Oxidative Coupling Reactions of Amines
한국공업화학회 연구논문 초록집, 2016
209 we have interested in the development of a novel protocol for the synthesis of structurally diverse 2-pyridone derivatives. Herein, we describe the catalyst-and solvent-free thermal reactions for the construction of diverse 2-pyridones. As an application, we also report on the Sun-protection ability of the synthesized compounds.
디젤엔진 배출가스 질소산화물 저감을 위한 Solid SCR용 Ammonium Carbonate 중간생성물인 재응고 물질의 분석 연구
Transactions of the Korean Society of Automotive Engineers, 2014
Urea solution as a reductant of SCR has been widely used to reduce NOx emissions from diesel engine. But it has lots of problems which are freezing at low temperature due to liquid state, deposition of solid formation in the exhaust, dosing device, and complex package such as mixers for uniform concentration of ammonia. In order to overcome these obstacle, ammonium carbonate which is one of solid ammonium materials to produce ammonia gas directly by sublimation process is considered. Simple reactor with visible widow was designed to predict equilibrium temperature and pressure of ammonium carbonate. To simulate real operation conditions under automobile environment, several cycles of heating and cooling condition were settled, two different re-solidification materials were extracted from the reactor and visible window. Analytical study is performed to characterize these unknown materials by XRD (X-Ray Diffraction), FT-IR(Fourier Transform Infrared Spectroscopy), and EA(Elemental Analyzer). From analytical results, re-solidification materials from heating and cooling cycles are very similar to original material of ammonium carbonate.
음폐수 이용 혐기성 소화의 내부 pH 조절에 따른 바이오가스 전환율 비교 및 미생물 군집도 분석
Journal of Korean Society of Environmental Engineers, 2013
In this study, the performance and microbial community of anaerobic digestion fed by food waste leachate at low organic loading rate were investigated with and without internal pH control. Experimental results show that similar biogas yield was achieved in both reactors regardless of increase in pH, the concentrations of free ammonia and volatile fatty acids in case of without internal pH controlled one. The results of a methanogenic community analysis by Polymerase Chain Reaction and Denaturing Gradient Gel Electrophoresis revealed that the apparent preponderance of Methanosarcina sp. could be one of reasons for the maintenance of reactor stability.
Bulletin of Materials Science, 2006
Poly(ε-caprolactone) (PCL) nanofibers and PCL/silica membranes were synthesized by sol-gel derived electrospinning and casting, respectively. Smooth PCL nanofibers were obtained from the precursor containing N,Ndimethylformamide (DMF). PCL/silica membranes were prepared by varying the tetraethyl orthosilicate (TEOS) contents from 0 to 40 vol% to investigate the effect of silica addition on mechanical properties and cytotoxicity of the membranes. Although the strength of the membranes decreased from 12 to 8 MPa with increasing the silica content, the strength remained almost constant 7 weeks after dipping in phosphate buffered saline solution (PBS). The strength reduction was attributed to the presence of a patterned surface pores and micro-pores present in the walls between pores. The crystal structure of the membranes was orthorhombic and the crystallite size decreased from 57 to 18 nm with increasing the silica content. From the agar overlay test, the PCL/silica membranes exhibited neither deformation and discoloration nor lysis of L-929 fibroblast cells.
Rechargeable Zn-air Energy Storage Cells Providing High Power Density
Journal of the Korean Industrial and Engineering Chemistry
Zn-Air energy storage cell is an attractive type of batteries due to its theoretical gravimetric energy density, cost-effective structure and environmental-friendly characteristics. The chargeability is the most critical in various industrial applications such as smart portable device, electric vehicle, and power storage system. Thus, it is necessary to reduce large overpotential of oxygen reduction/evolution reaction, the irreversibility of Zn anode, and carbonation in alkaline electrolyte. In this review, we try to introduce recent studies and developments of bi-functional air cathode, enhanced charge efficiency via modification of Zn anode structure, and blocking side reactions applying hybrid organic-aqueous electrolyte for high power density re-chargeable Zn-Air energy storage cells.
Han-gungnongnimgisanghakoeji, 2014
The physiological responses of three common temperate species, Pinus densiflora, Fraxinus rhynchophylla, Sorbus alnifolia to elevated CO 2 was investigated using open top chambers with different CO 2 concentrations. Morphological (stomatal size, density and area) and physiological characteristics (maximum rates of photosynthesis, carboxylation and electron transport) were compared among trees grown under ambient, ambient ×1.4 (~550 ppm) and ambient ×1.8 (~700 ppm) CO 2 concentrations for last four years. Morphological responses were different among species. F. rhynchophyllar increased their stomatal size and S. alnifolia had higher stomatal density under elevated CO 2 than ambient. Stomatal area decreased in P. densiflora, whereas it increased in S. alnifolia. However, the maximum photosynthesis rate increased in all species up to 43.5% by S. alnifolia under elevated CO 2 and the enhancement increased with time. Even with four years of exposure to elevated CO 2 , there was no sign of acclimation in the maximum carboxylation rate and the maximum electron transport rates in all species. Especially, S. alnifolia even showed the temporary increase of photosynthetic capacities in spring, when leaf nitrogen concentration was high with new leaf development. There was no significant differences in diameter growth rate in any species due to high variation in their tree sizes, however accumulated diameter and biomass for four years showed significantly increment in all species under elevated CO 2. For example, S. alnifolia showed 59% increase in diameter at the ambient ×1.8 (~700 ppm) compared to ambient.