• Journal of information and communication convergence engineering
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• v.11 no.4
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• pp.288-292
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• 2013

In this paper, a carbon implant is investigated in detail from the perspectives of performance advantages and side effects for the thick n-type metal-oxide-semiconductor field-effect transistor (n-MOSFET). Threshold voltage ($V_{th}$) adjustment using a carbon implant significantly improves the $V_{th}$ mismatch performance in a thick (3.3-V) n-MOS transistor. It has been reported that a bad mismatch occurs particularly in the case of 0.11-${\mu}m$ $V_{th}$ node technology. This paper investigates a carbon implant process as a promising candidate for the optimal $V_{th}$ roll-off curve. The carbon implant makes the $V_{th}$ roll-off curve perfectly flat, which is explained in detail. Further, the mechanism of hot carrier injection lifetime degradation by the carbon implant is investigated, and new process integration involving the addition of a nitrogen implant in the lightly doped drain process is offered as its solution. This paper presents the critical side effects, such as Isub increases and device performance shifts caused by the carbon implant and suggests an efficient method to avoid these issues.

• Korean Journal of Materials Research
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• v.29 no.9
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• pp.519-524
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• 2019

Spherical $Li_3V_2(PO_4)_3$ (LVP) and carbon-coated LVP with a monoclinic phase for the cathode materials are synthesized by a hydrothermal method using $N_2H_4$ as the reducing agent and saccharose as the carbon source. The results show that single phase monoclinic LVP without impurity phases such as $LiV(P_2O_7)$, $Li(VO)(PO_4)$ and $Li_3(PO_4)$ can be obtained after calcination at $800^{\circ}C$ for 4 h. SEM and TEM images show that the particle sizes are $0.5{\sim}2{\mu}m$ and the thickness of the amorphous carbon layer is approximately 3~4 nm. CV curves for the test cell are recorded in the potential ranges of 3.0~4.3 V and 3.0~4.8 V at a scan rate of $0.01mV\;s^{-1}$ and at room temperature. At potentials between 3.0 and 4.8 V, the third $Li^+$ ions from the carbon-coated LVP can be completely extracted, at voltages close to 4.51 V. The carbon-coated LVP exhibits an initial specific discharge capacity of $118mAh\;g^{-1}$ in the voltage region of 3.0 to 4.3 V at a current rate of 0.2 C. The results indicate that the reducing agent and carbon source can affect the crystal structure and electrochemical properties of the cathode materials.

• Transactions of Materials Processing
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• v.15 no.8 s.89
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• pp.581-585
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• 2006

Effects of V on both the formation of Ti-Nb-V carbonitrides and mechanical properties of Ti-Nb bearing low carbon HSLA steels were investigated. Hot rolling process was simulated by using Gleeble 3500 system with the steels containing three different levels of V ($0{\sim}0.1wt.%$). Vanadium precipitated as Ti-Nb-V carbonitrides at austenite region but it did not precipitate as VC during austenite to acicular ferrite or bainitic ferrite phase transformation. As V content increased, the amount of Nb precipitates was decreased but the average size of Ti-Nb-V carbonitrides was increased due to larger diffusivity of V than that of Nb. Coarsened Ti-Nb-V carbonitrides could act as heterogeneous nucleation site during ${\gamma}{\rightarrow}{\alpha}$ phase transformation, thus, acicular ferrite transformation was promoted as V content increased, resulting in increase of upper shelf energy.

• Composites Research
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• v.31 no.6
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• pp.412-420
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• 2018

In this work, phenolic resins containing conductive carbon fillers, such as, petroleum coke, carbon black, and graphite, were used to improve the surface heating elements by impregnating a pitch-based carbon paper. The influence of conductive carbon fillers on physicochemical properties of the carbon paper was investigated through electrical resistance measurement and thermal analysis. As a result, the surface resistance and interfacial contact resistivity of the carbon paper were decreased linearly by impregnating the carbon fillers with phenol resins. The increase of carbon filler contents led to the improvement of electrical and thermal conductivity of the carbon paper. Also, the heating characteristics of the surface heating element were examined through the applied voltage of 1~5 V. With the applied voltage, it was confirmed that the surface heating element exhibited a maximum heating characteristic of about $125.01^{\circ}C$(5 V). These results were attributed to the formation of electrical networks by filled micropore between the carbon fibers, which led to the improvement of electrical and thermal properties of the carbon paper.

• Journal of Radiation Protection and Research
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• v.41 no.4
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• pp.344-349
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• 2016

Background: Carbon ion therapy has achieved satisfactory results. However, patients have a risk to get a secondary cancer. In order to estimate the risk, it is essential to understand particle transportation and nuclear reactions in the patient's body. The particle transport Monte Carlo simulation code is a useful tool to understand them. Since the code validation for heavy ion incident reactions is not enough, the experimental data of the elementary reaction processes are needed. Materials and Methods: We measured neutron production double-differential cross-sections (DDXs) on a carbon bombarded with 430 MeV/nucleon carbon beam at PH2 beam line of HIMAC facility in NIRS. Neutrons produced in the target were measured with NE213 liquid organic scintillators located at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. Results and Discussion: Neutron production double-differential cross-sections for carbon bombarded with 430 MeV/nucleon carbon ions were measured by the time-of-flight method with NE213 liquid organic scintillators at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. The cross sections were obtained from 1 MeV to several hundred MeV. The experimental data were compared with calculated results obtained by Monte Carlo simulation codes PHITS, Geant4, and FLUKA. Conclusion: PHITS was able to reproduce neutron production for elementary processes of carbon-carbon reaction precisely the best of three codes.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1682-1688
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• 2005

Using the ASED-MO (Atom Superposition and Electron Delocalization-Molecular Orbital) theory, we investigated carbon formation and carbon hydrogenation for $CO_2$ methanation on the Ni (111) surface. For carbon formation mechanism, we calculated the following activation energies, 1.27 eV for $CO_2$ dissociation, 2.97 eV for the CO, 1.93 eV for 2CO dissociation, respectively. For carbon methanation mechanism, we also calculated the following activation energies, 0.72 eV for methylidyne, 0.52 eV for methylene and 0.50 eV for methane, respectively. We found that the calculated activation energy of CO dissociation is higher than that of 2CO dissociation on the clean surface and base on these results that the CO dissociation step are the ratedetermining of the process. The C-H bond lengths of $CH_4$ the intermediate complex are 1.21 $\AA$, 1.31 $\AA$ for the C${\cdot}{\cdot}{\cdot}H_{(1)}$, and 2.82 $\AA$ for the height, with angles of 105${^{\circ}}$ for ∠ $H_{(1)}$CH and 98${^{\circ}}$ for $H_{(1)} CH _{(1)}$.

• Bulletin of the Korean Chemical Society
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• v.18 no.2
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• pp.149-151
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• 1997

Barrier height on the surface was monitored at 77 K by observing the inflection of V-I characteristics of ZnO(1010)-ZnO(1010) contact in the surface reaction of oxygen species with carbon monoxide. The contact showed inflections at 10-20 mV and 10-50 mV for the sample adsorbed oxygen at 298 K and 573 K, respectively. When the sample adsorbed oxygen at 573 K was exposed to carbon monoxide at 298 K and 573 K, inflections were observed at 10-40 mV and 10-30 mV, respectively. The results indicated that the adsorption of oxygen on ZnO increased the surface barrier height, and the reaction of carbon monoxide with the oxygen-preadsorbed (at 573 K) ZnO decreased the surface barrier height.

• Food Science and Preservation
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• v.17 no.1
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• pp.84-90
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• 2010

We investigated methods to minimize patulin content during processing of apple juice in Korea. Ascorbic acid concentration (100, 200, 300, and 400 ppm) and activated carbon concentration (50, 100, 150, and 200 ppm) were the parameters assessed by response surface methodology. Residual patulin was lowest in the presence of 237.77 ppm ascorbic acid and 106.58 ppm activated carbon, and increased as these levels increased. Sugar content was affected more byascorbic acid concentration than by activated carbon level, and the total phenol content was revealed to be the saddle point. In addition, the expected total flavonoid content was maximized with increased levels of ascorbic acid and activated carbon. The data showed that 246-274 ppm (v/v) ascorbic acid and 93-122 ppm (v/v) activated carbon were optimal for juice extraction, and the $R^2$ quality factor for juice processing was significant and within the range of 1-10% for all tested parameters.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.151-154
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• 2002

The durability of two kinds of CFRP plates, carbon/UP and carbon/V, was studied under severe environmental conditions. Immersion into the chemical solutions and accelerated weathering were executed on the CFRP plates and the weight change under each condition was measured. After those treatments, the plates were tested by tensile testing machine to measure the mechanical properties and observed by SEM to find the damage behaviour of the surface. Comparing the virgin plates and the chemically exposed plates, both plates show severe deterioration of the mechanical properties. But, the plates subjected to alkali solution show much larger reduction than those of acidic solution and carbon/V has better chemical resistance than carbon/UP. The material properties of CFRP plate exposed to the weathering were deteriorated linearly proportional to the exposure time.

• Carbon letters
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• v.1 no.1
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• pp.27-30
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• 2000

Performance of direct methanol fuel cell using high porous active carbon as an uncatalysed diffusion layer in anode (composite electrode) has been evaluated. Effects of porous active carbon in anode were investigated by galvanostatic method and Fourier Transform Infrared spectroscopy. The single cell was operated with 2.5 M methanol at temperature of $80-120^{\circ}C$ and showed performance of $210-510\;mA/cm^2$ at 0.4V. By replacing conventional electrode with composite electrode, the increment of $290\;mA/cm^2$ in current density was obtained at $90^{\circ}C$and 0.4V. The potential decay of the single cell was about 14.5% for 20 days operation.