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pISSN : 1976-4251 / eISSN : 2233-4998

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2015, Vol.16, No.4

  • 1.

    Advances in liquid crystalline nano-carbon materials: preparation of nano-carbon based lyotropic liquid crystal and their fabrication of nano-carbon fibers with liquid crystalline spinning

    Yong-Mun Choi | JUNG JIN | Hwang, Junyeon and 4other persons | 2015, 16(4) | pp.223~232 | number of Cited : 1
    Abstract
    This review presents current progress in the preparation methods of liquid crystalline nanocarbon materials and the liquid crystalline spinning method for producing nano-carbon fibers. In particular, we focus on the fabrication of liquid crystalline carbon nanotubes by spinning from superacids, and the continuous production of macroscopic fiber from liquid crystalline graphene oxide.
  • 2.

    Electrochemical synthesis of nanosized hydroxyapatite/ graphene composite powder

    Vesna Mišković-Stanković | Sanja Eraković | Ana Janković and 5other persons | 2015, 16(4) | pp.233~240 | number of Cited : 2
    Abstract
    Electrochemical synthesis was employed to prepare a novel hydroxyapatite/graphene (HAP/ Gr) composite powder suitable for medical applications as a hard tissue implant (scaffold). The synthesis was performed in a homogeneous dispersion containing Na2H2EDTA·2H2O, NaH2PO4 and CaCl2 with a Ca/EDTA/PO4 3− concentration ratio of 0.25/0.25/0.15M, along with 0.01 wt% added graphene nanosheets, at a current density of 137 mA cm−2 and pH value of 9.0. The field emission scanning electron microscopy and transmission electron microscopy observations of the composite HAP/Gr powder indicated that nanosized hydroxyapatite particles were uniformly placed in the graphene overlay. Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction confirmed graphene incorporation in the HAP/Gr powder. The electrochemically prepared HAP/Gr composite powder exhibited slight antibacterial effect against the growth of the bacterial strain Staphylococcus aureus.
  • 3.

    Influence of laminated orientation on the mechanical and thermal characteristics of carbon-fiber reinforced plastics

    SHIN HEE JAE | Kwac Lee-Ku | 이민상 and 1other persons | 2015, 16(4) | pp.241~246 | number of Cited : 1
    Abstract
    Rapid industrial development in recent times has increased the demand for light-weight materials with high strength and structural integrity. In this context, carbon fiber-reinforced plastic (CFRP) composite materials are being extensively used. However, laminated CFRPs develop faults during impact because CFRPs are composed of mixed carbon fiber and epoxy. Moreover, their fracturing behavior is very complicated and difficult to interpret. In this paper, the effect of the direction of lamination in CFRP on the absorbed impact energy and impact strength were evaluated, including symmetric ply (0°/0°, –15°/+15°, –30°/+30°, –45°/+45°, and –90°/+90°) and asymmetric ply (0°/15°, 0°/30°, 0°/45°, and 0°/90°), through drop-weight impact tests. Further, the thermal properties of the specimens were measured using an infrared camera. Correlations between the absorbed impact energy, impact strength, and thermal properties as determined by the drop-weight impact tests were analyzed. These analyses revealed that the absorbed impact energy of the specimens with asymmetric laminated angles was greater than that of the specimens with symmetric laminated angles. In addition, the asymmetry ply absorbed more impact energy than the symmetric ply. Finally, the absorbed impact energy was inversely proportional to the thermal characteristics of the specimens.
  • 4.

    Photocatalytic performance of graphene/Ag/TiO2 hybrid nanocomposites

    Jong-Ho Lee | Kim In Ki | Donghwan Cho and 3other persons | 2015, 16(4) | pp.247~254 | number of Cited : 2
    Abstract
    To improve photocatalytic efficiency, graphene/Ag/TiO2 nanotube catalyst was synthesized, and its surface characteristics and photocatalytic activity investigated. For deposition of Ag nanoparticles on the TiO2 nanotubes, a polymer compound containing CH3COOAg/poly(Llactide) was utilized, and the silver particles were precipitated by reducing the silver ions during the annealing process. Graphene deposition on the Ag/TiO2 nanotubes was achieved using an electrophoretic deposition process. Based on the dye degradation results, it was determined that the photocatalytic efficiency was significantly affected by deposition of silver particles and graphene on the TiO2 catalyst. Highly efficient destruction of the dye was obtained with the new graphene/Ag/TiO2 nanotube photocatalyst. This may be attributed to a synergistic effect of the graphene and Ag nanoparticles on the TiO2 nanotubes.
  • 5.

    Structural properties of reduced graphene oxides prepared using various reducing agents

    이병수 | Yangjin Lee | Hwang, Junyeon and 1other persons | 2015, 16(4) | pp.255~259 | number of Cited : 2
    Abstract
    Graphene has been attracting a great deal of attention because of its unique and advantageous properties such as high electrical [1,2] and thermal conductivity [3], good mechanical strength [4,5], large specific surface area [6], and extreme carrier mobility [7]. The excellent electronic properties of graphene have driven extensive studies on its application in field effect transistors [8], memory devices [9], transparent conductive films [10], and so on. Furthermore, this novel nano-carbon material can also be used in composites [11-13], energy storage media [6,14,15], gas sensors [16], and bio sensors [17] owing to its superb structural, optical, and mechanical properties.
  • 6.

    Catalytic activity and controllable deposition of platinum nanoparticles on ionic polymer-functionalized graphene as catalysts for direct methanol fuel cells

    Park Ji-Young | 송찬윤 | Qizhong Sun and 2other persons | 2015, 16(4) | pp.260~264 | number of Cited : 1
    Abstract
    Direct methanol fuel cells (DMFCs) are considered promising candidates for mobile and transport applications due to their high energy density, zero emissions, and relatively low operating temperature [1]. Moreover, platinum (Pt) is an excellent catalyst and one of the best electrode materials for DMFCs [2-4]. However, the high cost, low electrocatalytic activity and stability of common Pt catalyst inhibit their broad application for DMFCs [3]. It is well known that the electrocatalytic performance of a fuel cell greatly depends on the composition, shape, size, and dispersion of the catalyst nanoparticles (NPs). The materials supporting catalyst play an important role in controlling these properties [5]. However, during fuel-cell operation, a gradual oxidation of the carbon support leads to detachment of Pt NPs from the carbon support, allowing their agglomeration, which can reach an unacceptable level [6].
  • 7.

    Effects of digestion temperatures and loading amounts on methane production from anaerobic digestion with crop residues

    신정두 | Park Sang Won | Sun Il Lee and 3other persons | 2015, 16(4) | pp.265~269 | number of Cited : 1
    Abstract
    Due limited natural resources and increased greenhouse gas emissions, substitution of fossil fuels with renewable bio-energy has been encouraged United Nations Framework Convention on Climate Change (UNFCCC). According to the United Nations, by the year 2050, up to 77% of the world’s energy demand could be supplied by renewable energy sources [1]. However, because biomass has gained economic interest, further expansion of biogas production is increasingly dependent on the exploitation of new sources of biomass.
  • 8.

    Experimental study on synthesis of Co/CeO2-doped carbon nanofibers and its performance in supercapacitors

    김종완 | Zafar Khan Ghouri | Rabia Zafar Khan and 3other persons | 2015, 16(4) | pp.270~274 | number of Cited : 1
    Abstract
    Because of avaricious global energy consumption, and serious environmental issues, the demand for clean energy technology has grown to a significant level, and the development of emerging effective energy devices and resources has become one of the most important topics in recent decades, and has attracted passionate research [1]. Among encouraging alternative sources of energy, supercapacitors are one of the promising electrochemical energy storage devices, with high power characteristics compared to batteries, high energy density compared to conventional capacitors, and long cycling times [2-6].
  • 9.

    Potassium hydroxide activation of activated carbon: a commentary

    Tang Shu Hui | Muhammad Abbas Ahmad Zaini | 2015, 16(4) | pp.275~280 | number of Cited : 4
    Abstract
    Over the years, the furnace has been used as a common heating method to manufacture activated carbon. In a furnace, heat is transferred through conduction and convection. The outer surface of the sample is in contact with the generated heat, which slowly diffuses inwards as a result of the thermal gradient between the surface and the core of the material’s particles. Another method of heating employs microwave irradiation. Even though it is less energy- and time-consuming, the microwave method has several critical issues with respect to temperature control and thermal runaway, especially in the scaling-up of the microwave heating process [1].
  • 10.

    Effect of nickel on hydrogen storage behaviors of carbon aerogel hybrid

    한예지 | PARK SOOJIN | 2015, 16(4) | pp.281~285 | number of Cited : 1
    Abstract
    Limited conventional energy resources and serious environmental calamities have motivated researchers to find new and efficient sources of energy. The considerable efforts devoted to this end include the development of bio-diesel, solar cells, coal liquefaction/ gasification technologies, and fuel cells. Hydrogen is considered by many an ideal energy source owing to its renewable and clean energy characteristics. In addition, it mostly produces water, which is eco-friendly compared to the byproducts of many other energy sources [1-6]. To use hydrogen as an energy source, various hydrogen storage methods such as the use of metal hydrides, liquefied hydrogen, and adsorption of hydrogen in porous materials have been studied [7-14]. The adsorption of hydrogen in porous materials is particularly suitable for hydrogen storage, which is critical for suitably utilizing hydrogen energy, owing to the reversibility and stability of this method. To date, the wide ranging attempts to develop hydrogen storage mechanisms include studies on carbon materials [15-17], metal-organic frameworks, and zeolites [18-21]. Carbon materials offer many advantages for hydrogen storage, such as easy preparation, suitable surface functional groups, low mass density, thermal stability, and hydrophobicity [22-24]. Carbon aerogels (CAs) in particular have been recognized as potential hydrogen storage materials because of their suitable structural properties, controllable mass densities, high specific surface areas, and mesopore volumes. However, it is necessary to modify the surfaces of carbon materials in order to reach the hydrogen storage capacities determined by the US Department of Energy (DOE).