• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.132.2-132.2
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• 2010

Mesoporous tinoxide ($SnO_2$) as anode materials for Li-ion battery were prepared by hydrothermal method and templating method using SBA-15 as template. And electrochemical properties of $SnO_2$ electrode were investigated with cyclic voltammogram (CV). The morphology and structures of $SnO_2$ were characterized by transmission electron microscopy (TEM) and X-ray diffractometer (XRD), respectively. The specific surface area was defined by $N_2$ adsorption with BET(Brunauer-Emmett-Teller) method. As a result, the surface area of mesoporous $SnO_2$ which was made from templating method is higher than the case of using hydrothermal method. In addition, in anodic performance, mesoporous $SnO_2$ which is prepared by templating method showed higher charge-discharge capasity compared to hydrothermal method and exhibited excellent stability over the entire cycle number. It was indicated that electrochemical performances of mesoporous $SnO_2$mainly affected to the structural features, such as specific surface area and porosity.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.423-428
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• 2010

To reduce polarization of electrochemical capacitor based on carbon nanotube, titanium oxide nanoparticles were deposited by ultrasound. The pore distribution of $TiO_2$/CNT nanoparticle exhibited surface area of $341\;m^2g^{-1}$ when $TiO_2$ content was 4 wt %, which was better than that of pristine CNT with surface area of $188\;m^2g^{-1}$. The analyses indicated that titanium oxide (particle diameter < 20 nm) was deposited on the CNT surface. The electrochemical performance was evaluated by using cyclic voltammetry (CV), impedance measurement, and constant-current charge/discharge cycling techniques. The $TiO_2$/CNT composite electrode showed relatively better electrochemical behaviors than CNT electrode by increasing the specific capacitance from $22\;Fg^{-1}$ to $37\;Fg^{-1}$ in 1 M $H_2SO_4$ solution. A symmetric cell assembled with the composite electrodes showed the specific capacitance value of $11\;Fg^{-1}$ at a current loading of $0.5\;mAcm^{-2}$ during initial cycling.

• Journal of the Korean Electrochemical Society
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• v.16 no.2
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• pp.65-69
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• 2013

In order to improve capacitance of activated carbon for electric double layer capacitors, peptide bond was induced on the surface of the activated carbon by urea. Urea induced activated carbon has been stabilized through carbonization. Electrochemical characteristics was observed by cyclic voltammetry for specific capacitance, electrochemical impedance spectroscope for measuring resistance and charge-discharge for testing the cyclic ability. In the result, specific capacitance is increased about 22.9% than the activated carbon. And it shows excellent cycle performance and decreasing resistance with the introduction of nitrogen functional groups.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.1
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• pp.51-58
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• 2002

Destruction process of toluene using a wire-cylindrical BBD (Dielectric Barrier Discharge) reactor packed with catalysts was investigated to characterize the synergetic effects of non-thermal plasma and catalyst process. The catalysts used in the present study were ${\gamma}$-Al$_2$BO$_3$ and Pt/${\gamma}$-Al$_2$O$_3$. Under the numerous test conditions, specific energy density (SED (J/L)) and the conversion of toluene, defined as (1 -[C$_{f}$]/[C$_{i}$]), were measured. The test results showed that toluene decomposition efficiency followed the pseudo-first order in the case of plasma only process. The pseudo-first order process, however, was modified to pseudo-zeroth order reaction in the case of catalyst-assisted plasma process. This modification of the reaction order was verified based on a simple kinetic model proposed in the present study. Owing to the modification of reaction order, which resulted from the catalytic process, the specific energy to achieve the high removal efficiencies, i.e. 80~90%, was reduced significantly.y.y.

• Korean Journal of Veterinary Service
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• v.38 no.1
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• pp.31-36
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• 2015

Two cats were obtained from a cat kennel. Over the previous 7 days, the cats had shown cough, anorexia, depression and nasal discharge. In this study, the consensus PCR was able to detect successfully Mycoplasma species in nasal swab samples of the cats. To identify feline mycoplasma species from the lung tissue of the cats with pneumonia, Mycoplasma species-specific PCR reactions were conducted. As the results, we could identify M. felis by the positive amplified DNAs. On the other hand, we could not detect any positive reactions with the PCR reaction for M. arginini, M. canis, M. edwardii, M. cynos, M. gateae, M. maculosum, M. molared, M. opalescens, M. spumans and Mycoplasma HRC-689. In conclusion, we detected M. felis from the kenneled cats with pneumonia. We suggested that this consensus PCR would be useful and effective for monitoring Mycoplasma species in various kinds of animals including cats. The application of preceding consensus PCR before the species-specific PCRs may be the most recommended strategy for the identification of Mycoplasma spp.

• Journal of Chest Surgery
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• v.15 no.4
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• pp.447-450
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• 1982

A 45 year old male officer was admitted due to upper substernal pain for 1 month, which was aggravated by swallowing. On past and family history, there was no specific history except heavy drinking. Simple chest x-ray revealed no specific abnormal findings. Preoperative esophagofiberscopy and Barium study showed midesophageal diverticulum, pulsion type, at about 2 cm below the left main bronchus. The opening of the diverticulum was located at the left posterolateral aspect of esophagus. Midesophageal false diverticulum, measuring 2 x 2 x 1 .S cm in size, was noted at about 5 cm under the aortic arch protruding through a slit-like muscular defect. After inversion of diverticular sac, interrupted sutures with 3-0 silks were done on muscular defect site, and mediastinal pleura was reinforced on the lesion with interrupted sutures. On 4th postoperative day, esophagography revealed no diverticulum or stenosis. Also esophagofiberscopy showed smooth mucosal tag without disturbance of passage. On 14th postoperative day, the patient was discharged uneventfully, and follow-up for 3 months after discharge revealed nothing abnormal symptoms. The authors report one case of midesophageal, pulsion type, false diverticulum.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.1
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• pp.95-102
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• 2006

The PPT being currently developed for the flight model represents a significant leap in techniques and technology compared to the previous flight ones. The electrical energy to be charged in the pulsed plasma thruster (PPT) is a very important aspect to provide an uniform impulse bit ,, and a specific impulse ,, for satellite attitude control. In this paper, we propose a nonlinear control technique and a stability analysis based on the Lyapunov function for the pulsed plasma thruster. Specifically, the proposed control law guarantees to charge and discharge the electrical energy generated from the power processing unit (PPU) within the specified time.

• Journal of the Korean institute of surface engineering
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• v.51 no.1
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• pp.47-53
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• 2018

Sn-based lithium-ion batteries have low cost and high theoretical specific capacity. However, one of major problem is the capacity fading caused by volume expansion during lithiation/delithiation. In this study, 3-dimensional foam structure of Cu-Sn alloy is prepared by co-electrodeposition including large free space to accommodate the volume expansion of Sn. The Cu-Sn foam structure exhibits highly porous and numerous small grains. The result of EDX mapping and XPS spectrum analysis confirm that Cu-Sn foam consists of $SnO_2$ with a small quantity of CuO. The Cu-Sn foam structure electrode shows high reversible redox peaks in cyclic voltammograms. The galvanostatic cell cycling performances show that Cu-Sn foam electrode has high specific capacity of 687 mAh/g at a current rate of 50 mA/g. Through SEM observation after the charge/discharge processes, the morphology of Cu-Sn foam structure is mostly maintained despite large volume expansion during the repeated lithiation/delithiation reactions.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.5
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• pp.189-193
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• 2003

Initial irreversible capacity (IIC) can be defined by means of the initial intercalation Ah efficiency (IIE) and the initial irreversible specific capacity at the surface (IICs) with the linear-fit range of the intercalation so as to precisely express the irreversibility of an electrode-electrolyte system. Their relationship was IIC = Qc - Q$_{D}$ = (IIE$^{-1}$ - 1) Q$_{D}$ + IICs in the linear-fit range of IIE. Here, Qc and Qd signify charge and discharge capacity, respectively, based on a complete lithium ion battery cell. Charge indicates lithium insertion to carbon anode. Two terms of IIE and IICs depended on the types of active materials and compositions of the electrode and electrolyte but did not change with charging state. In an ideal electrode-electrolyte system, IIE and IICs would be 100%, 0 mAh/g for the electrode and mAh for the cell, respectively. These properties can be easily obtained by the Gradual Increasing of State of Charge (GISOC).OC).

• Carbon letters
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• v.23
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• pp.9-16
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• 2017

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 ($S_{BET}$) and total pore volume reached $778m^2g^{-1}$ and $1.17cm^3g^{-1}$, 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 $328Fg^{-1}$, 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.