Carbon Letters Vol.23 - koreascholar

1.

2017.06 구독 인증기관 무료, 개인회원 유료

Hole quality assessment of drilled CFRP and CFRP-Ti stacks holes using polycrystalline diamond (PCD) tools

Dave Kim, Aaron Beal, Kiweon Kang, Sang-Young Kim

Polycrystalline diamond (PCD) tools possessing high hardness and abrasive wear resistance are particularly suited for drilling of carbon fiber reinforced plastic (CFRP) composites, where tool life and consistent hole quality are important. While PCD presents superior performance when drilling CFRP, it is unclear how it performs when drilling multi-stack materials such as CFRP-titanium (Ti) stacks. This comparative study aims to investigate drilling of a Ti plate stacked on a CFRP panel when using PCD tools. The first sequence of the drilling experiments was to drill 20 holes in CFRP only. CFRP-Ti stacks were then drilled for the next 20 holes with the same drill bit. CFRP holes and CFRP-Ti stack holes were evaluated in terms of machined hole quality. The main tool wear mechanism of PCD drills is micro-fractures that occur when machining the Ti plate of the stack. Tool wear increases the instability and the operation temperature when machining the Ti plate. This results in high drilling forces, large hole diameter errors, high surface roughness, wider CFRP exit thermal damage, and taller exit Ti burrs.

4,000원

2.

2017.06 구독 인증기관 무료, 개인회원 유료

Fabrication of nitrogen doped ordered mesoporous carbon derived from glucosamine with hybrid capacitive behaviors

Deyi Zhang, Mei Han, Yubing Li, Bing Wang, Yi Wang, Kunjie Wang, Huixia Feng

Carbon Letters Vol.23 pp.9-16 한국탄소학회

This paper introduces a nitrogen-doped ordered mesoporous carbon (NOMC) derived from glucosamine with hybrid capacitive behaviors, achieved by successfully combining electrical double-layer capacitance with pseudo-capacitance behaviors. The nitrogen doping content of the fabricated NOMC reached 7.4 at% while its specific surface area (SBET) and total pore volume reached 778 m2 g−1 and 1.17 cm3 g−1, respectively. A dual mesoporous structure with small mesopores centered at 3.6 nm and large mesopores centered at 9.9 nm was observed. The specific capacitance of the reported materials reached up to 328 F g−1, which was 2.1 times higher than that of pristine CMK-3. The capacitance retention rate was found to be higher than 87.9% after 1000 charge/discharge cycles. The supplementary pseudocapacitance as well as the enhanced wettability and conductivity due to the incorporation of nitrogen heteroatoms within the carbon matrixes were found to be responsible for the excellent capacitive performance of the reported NOMC materials.

4,000원

3.

2017.06 구독 인증기관 무료, 개인회원 유료

Synthesis, characterization, and antibacterial performance of Ag-modified graphene oxide reinforced electrospun polyurethane nanofibers

Bishweshwar Pant, Mira Park, Rae-Sang Jang, Woo-Cheol Choi, Hak-Yong Kim, Soo-Jin Park

Carbon Letters Vol.23 pp.17-21 한국탄소학회

Polyurethane (PU) nanofibers containing graphene oxide (GO) and Ag doped functionalized reduced graphene oxide (Ag-RGO) were successfully prepared via the electrospinning technique. The uniform distribution of GO sheets along with Ag nanoparticle in the nanoﬁbers was investigated by scanning electron microscopy and the elemental mapping technique. X-ray diffraction and thermal gravimetric analysis veriﬁed the presence of GO and Ag in the bicomposite nanoﬁbrous mats. Antibacterial tests against Escherichia coli demonstrated that the addition of GO and Ag-RGO to the PU nanoﬁber greatly enhanced bactericidal efficiency. Overall, these features of the synthesized nanoﬁbers make them a promising candidate material in the biomedical field for applications such as tissue engineering, wound healing, and drug delivery systems.

4,000원

4.

2017.06 구독 인증기관 무료, 개인회원 유료

Mechanical and electrical properties of cement paste incorporated with pitch-based carbon fiber

Inkyu Rhee, Jin Hee Kim, Sang Hee Park, Sungho Lee, Bong Ryeul Ryu, Yoong Ahm Kim

Carbon Letters Vol.23 pp.22-29 한국탄소학회

The compressive strength and electrical resistance of pitch-based carbon fiber (CF) in cementitious materials are explored to determine the feasibility of its use as a functional material in construction. The most widely used CFs are manufactured from polyacrylonitrile (PAN-based CF). Alternatively, short CFs are obtained in an economical way using pitch as a precursor in a melt-blown process (pitch-based CF), which is cheaper and more eco-friendly method because this pitch-based CF is basically recycled from petroleum residue. In the construction field, PAN-based CFs in the form of fabric are used for rehabilitation purposes to reinforce concrete slabs and piers because of their high mechanical properties. However, studies have revealed that construction materials with pitch-based CF are not popular. This study explores the compressive strength and electrical resistances of a cement paste prism using pitch-based CF.

4,000원

5.

2017.06 구독 인증기관 무료, 개인회원 유료

Adsorption of Nile Blue A from aqueous solution by different nanostructured carbon adsorbents

Shahryar Abbasi, Hadi Noorizadeh

Carbon Letters Vol.23 pp.30-37 한국탄소학회

Dyes are widely used in various industries including textile, cosmetic, paper, plastics, rubber, and coating, and their discharge into waterways causes serious environmental and health problems. Four different carbon nanostructures, graphene oxide, oxidized multi-walled carbon nanotubes, activated carbon and multi-walled carbon nanotubes, were used as adsorbents for the removal of Nile Blue A (NBA) dye from aqueous solution. The four carbon nanostructures were characterized by scanning electron microscope and X-ray diffractometer. The effects of various parameters were investigated. Kinetic adsorption data were analyzed using the first-order model and the pseudo-second-order model. The regression results showed that the adsorption kinetics were more accurately represented by the pseudo-second-order model. The equilibrium data for the aqueous solutions were fitted to Langmuir and Freundlich isotherms, and the equilibrium adsorption of NBA was best described by the Langmuir isotherm model. This is the first research on the removal of dye using four carbon nanostructures adsorbents.

4,000원

6.

2017.06 구독 인증기관 무료, 개인회원 유료

Electrochemical determination of chloramphenicol using a glassy carbon electrode modified with dendrite-like Fe3O4 nanoparticles

Krishnan Giribabu, Sung-Chan Jang, Yuvaraj Haldorai, Muruganantham Rethinasabapathy, Seo Yeong Oh, Arunkumar Rengaraj, Young-Kyu Han, Wan-Seob Cho, Changhyun Roh, Yun Suk Huh

Carbon Letters Vol.23 pp.38-47 한국탄소학회

In this study, magnetite (Fe3O4) nanoparticles were electrochemically synthesized in an aqueous electrolyte at a given potential of -1.3 V for 180 s. Scanning electron microscopy revealed that dendrite-like Fe3O4 nanoparticles with a mean size of < 80 nm were electrodeposited on a glassy carbon electrode (GCE). The Fe3O4/GCE was utilized for sensing chloramphenicol (CAP) by cyclic voltammetry and square wave voltammetry. A reduction peak of CAP at the Fe3O4/GCE was observed at 0.62 V, whereas the uncoated GCE exhibited a very small response compared to that of the Fe3O4/GCE. The electrocatalytic ability of Fe3O4 was mainly attributed to the formation of Fe(VI) during the anodic scan, and its reduction to Fe(III) on the cathodic scan facilitated the sensing of CAP. The effects of pH and scan rate were measured to determine the optimum conditions at which the Fe3O4/GCE exhibited the highest sensitivity with a lower detection limit. The reduction current for CAP was proportional to its concentration under optimized conditions in a range of 0.09-47 μM with a correlation coefficient of 0.9919 and a limit of detection of 0.09 μM (S/N=3). Moreover, the fabricated sensor exhibited anti-interference ability towards 4-nitrophenol, thiamphenicol, and 4-nitrobenzamide. The developed electrochemical sensor is a cost effective, reliable, and straightforward approach for the electrochemical determination of CAP in real time applications.

4,000원

7.

2017.06 구독 인증기관 무료, 개인회원 유료

Effect of added mesophase pitch during the pitch synthesis reaction of PFO

Ji Hong Kim, Jong Gu Kim, Chul Wee Lee, Ki Bong Lee, Ji Sun Im

Carbon Letters Vol.23 pp.48-54 한국탄소학회

This research considers the effect of added mesophase pitch (MP) as an additive during the pitch synthesis reaction of pyrolyzed fuel oil (PFO). Two effects are generated by adding MP. One is an enhancement of thermal stability due to the high thermal property of the additive; the other is that the volatile compounds that were removed by vaporization of PFO during the thermal reaction can participate in the pitch synthesis reaction (PFO→pitch) more efficiently. The effect differs according to the amount of the additive. When the amount of the additive is less than 7 wt%, the first effect is dominant, whereas the second effect is dominant when the additive amount exceeds 10 wt%.

4,000원

8.

2017.06 구독 인증기관 무료, 개인회원 유료

Dispersions of partially reduced graphene oxide in various organic solvents and polymers

Hye Min Kim, Seo Gyun Kim, Heon Sang Lee

Carbon Letters Vol.23 pp.55-62 한국탄소학회

We report on the dispersion state of partially reduced graphene oxide (PRGO) in organic solvents, namely methyl ethyl ketone, ethyl acetate, methylene chloride, toluene, and xylene, by controlling the carbon to oxygen (C/O) atomic ratio of the PRGOs. A two-phase solvent exchange method is also proposed to transfer PRGO from water to an aprotic solvent, such as methyl ethyl ketone. We achieve relatively good dispersion in aprotic and non-polar solvents by controlling the C/O atomic ratio of the PRGOs and applying the two-phase solvent exchange method. There is an increase in the glass transition temperatures with the dispersion of PRGOs into amorphous polymers, in particular a 4.4°C increase for poly(methyl methacrylate) and 3.0°C increase for polycarbonate. Good dispersion of PRGO in a nonpolar polymer, such as linear low density polyethylene, is also obtained.

4,000원

9.

2017.06 구독 인증기관 무료, 개인회원 유료

Capacitance behaviors of conducting polymer-coated graphene nanosheets composite electrodes containing multi-walled carbon nanotubes as additives

Hoe-Seung Kim, Yongju Jung, Seok Kim

Carbon Letters Vol.23 pp.63-68 한국탄소학회

4,000원

10.

2017.06 구독 인증기관 무료, 개인회원 유료

Lyocell-based activated carbon fibers improved the adsorption of harmful gas properties when produced via dual-simultaneous treatments

Byong Chol Bai, Ji Sun Im, Young-Seak Lee

Carbon Letters Vol.23 pp.69-73 한국탄소학회