• 한국세라믹학회지
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• 제48권6호
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• pp.549-558
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• 2011

Application of a generalized equivalent circuit including the electrode condition for the Hebb-Wagner polarization in the frequency domain proposed by Jamnik and Maier can provide a consistent set of material parameters, such as the geometric capacitance, partial conductivities, chemical capacitance or diffusivity, as well as electrode characteristics. Generalization of the shunt capacitors for the chemical capacitance by the constant phase elements (CPEs) was applied to a model mixed conducting system, $Ag_2S$, with electron-blocking AgI electrodes and ion-blocking Pt electrodes. While little difference resulted for the electron-blocking cell with almost ideal Warburg behavior, severely non-ideal behavior in the case of Pt electrodes not only necessitates a generalized transmission line model with shunt CPEs but also requires modelling of the leakage in the cell approximately proportional to the cell conductance, which then leads to partial conductivity values consistent with the electron-blocking case. Chemical capacitance was found to be closer to the true material property in the electron-blocking cell while excessively high chemical capacitance without expected silver activity dependence resulted in the electron-blocking cell. A chemical storage effect at internal boundaries is suggested to explain the anomalies in the respective blocking configurations.

• 한국세라믹학회지
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• 제45권3호
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• pp.161-166
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• 2008

The multi-films of a metallic film and a transparent conducting oxide (TCO, indium-tin oxide, ITO) film were formed on the stainless steel 316 and 304 plates by a sputtering method and an E-beam method and then the external metallic region of the stainless steel bipolar plates was converted into the metal nitride films through an annealing process. The multi-film formed on the stainless steel bipolar plates showed the XRD patterns of the typical indium-tin oxide, the metallic phase and the metal substrate and the external nitride film. The XRD pattern of the thin film on the bipolar plates modified showed two metal nitride phases of CrN and $Cr_2N$ compound. Surface microstructural morphology of the multi-film deposited bipolar plates was observed by AFM and FE-SEM. The metal nitride film formed on the stainless steel bipolar plates represented a microstructural morphology of fine columnar grains with 10 nm diameter and 60nm length in FE-SEM images. The electrical resistivity of the stainless steel bipolar plates modified was evaluated.

• 한국주거학회논문집
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• 제20권4호
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• pp.49-57
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• 2009

Established redevelopment and reconstruction projects were unified into one law in 2003 when the 'Act of Urban, Residential and Environment Improvement' was enacted. However, the act only focused on the improvement of the physical state of residential environments established by maintenance projects. In order to be effective, the law also needs to improve the nonphysical aspects of the residential environment. While conducting our research and comparing it with past research, we identified the major factors of residential preferences in order to extract and analyze the nonphysical state of residential environments. As a result, we found that social and economic factors are significantly more important to residents than cultural factors. Also, we found that in each district studied the housing preferences were the most important in redevelopment and reconstruction with the exception of Sangdang-Gu (where the community was the most important factor) and Hungduk-Gu (where the social factor was most important). For future purposes, it is necessary to consider the variables according to each location in order to reflect the needs of the residents when building an apartment complex within the redevelopment and reconstruction district.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.873-875
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• 1999

We have fabricated good quality superconducting $YBa_{2}Cu_{3}O_{7-\delta}$ thin films on Hastelloy(Ni-Cr-Mo alloys) metallic substrate with $CeO_2$ and $BaTiO_3$ buffer layers in-situ by pulsed laser deposition in a multi-target processing chamber. We have chosen $CeO_2$ as a buffer layer which has cubic structure of $5.41{\AA}$ lattice parameter and only 0.2% of lattice mismatch with YBCO. $CeO_2$ layer may be helpful for power transmission due to its conducting property. In order to enhance the crystallization of YBCO films on metallic substrates. we deposited $CeO_2$ and $BaTiO_3$ buffer layers at various temperatures. The YBCO superconducting tape fabricated with $BaTiO_3$ and $CeO_2$ buffer layers shows 85K of transition temperature and about $8.4{\times}10^4A/cm^2$ of critical current density at 77K.

• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.930-935
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• 2004

$({Li}_{0.5}0{La}_{0.5}){TiO}_3$ (LLTO) solid electrolyte was grown on LiCo{O}_2 (LCO) cathode films deposited on $Pt/Ti{O}-2/Si{O}_2/Si$ substrate using pulsed laser deposition for all-solid-state lithium microbattery. LLTO solid electrolyte exhibits an amorphous phase at various deposition temperatures. LLTO films deposited at 10$0^{\circ}C$ showed a clear interrace without any chemical reaction with LCO, and showed an initial discharge capacity of 50 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 90 % after 100 cycles with Li anode in 1mol$ LiCl{O}_4$ in propylene carbonate (PC). The increase of capacity retention in LLTO/LCO structure than LCO itself was attributed to the structural stability of LCO cathode films by the stacked LLTO. The cells of LLTO/LCO with LLTO grown at $100^{\circ}C$ showed a good cyclic property of 63.6 % after 300 cycles. An amorphous LLTO solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium microbattery.

• Applied Science and Convergence Technology
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• 제27권2호
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• pp.30-34
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• 2018

Conducting and semiconducting temperature sensors are calibrated and applied to cryomodules. The definition of temperature is introduced and the pressure in vacuum is shown as a function of temperature. The resistance of Drude model is shown as a function of carrier density and mean free path. Temperature sensors are calibrated with Physical Property Measurement System (PPMS). The temperature sensors are applied to measure temperature accurately in RAON cryomodules.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.110-116
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• 2002

At elevated temperature, very complex precipitations occur in STS316. To investigate the effect of the precipitation on mechanical properties in SIS316, tensile tests and fatigue crack growth tests were carried out at $650^{\circ}C$ using artificially degraded materials. The material degradation was simulated by aging for up to 20000 hrs. at $750^{\circ}C$, which is equal to 179000hrs (about 20yrs) of service life at $650^{\circ}C$, after conducting solution treatment for 20 min. at $11300^{\circ}C$. The result of the hardness test and the tensile test showed that both properties are closely related to the mean free distance of carbides. Also, from the results of fracture tests at $650^{\circ}C$, ${\triangle}K_{th}$, after values were found to decrease as aging time and microstructure, as the volume fraction of $\sigma$ phase increased.

• Journal of Electrochemical Science and Technology
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• 제2권4호
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• pp.211-215
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• 2011

Flexible sheets consisting of acrylonitrile-butadiene rubber (NBR) and carbon nanotube (CNT) are newly prepared varying the composition (CNT 20-25 wt.%) for use as a current collector of supercapacitor electrodes. The as-prepared CNT/NBR is electrodeposited with aniline using potentiodynamic cyclic voltammetry to yield a polyaniline (PANI)/CNT/NBR composite electrode. It is confirmed that the electrical conductivity of CNT/NBR current collector can be enhanced as the content of CNT increases. Cyclic voltammetry result shows that the sample of PANI/CNT(25 wt.%)/NBR composite achieves a maximum specific capacitance ($134.9\;F\;g^{-1}$) at $5\;mV\;s^{-1}$. Such supercapacitor application is possibly originated from the synergistic effects consisting of higher polarity of nitrile groups in NBR, conducting pathway of CNT, and electroactive property of PANI.

• 한국세라믹학회지
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• 제51권2호
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• pp.103-106
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• 2014

Nacre is an organic-inorganic composite material; it is composed of $CaCO_3$ platelet and protein. The microstructure of nacre is a matrix that is similar to bricks and mortar. Technology inspired by nature is called biomimetic technology. In this study, to make high thermal conducting ceramic composite materials using biomimetic technology, a porous green body was prepared with BN platelets. PMMA was infiltrated into the porous green body to make a composite. The microstructure of the composite was observed with FESEM, and the thermal properties were measured. The thermal conductivity of the prepared organic-inorganic composite was 4.19 $W/m{\cdot}K$.

• Journal of Ginseng Research
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• 제32권2호
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• pp.150-154
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• 2008

Twenty five albino rats were divided into five groups for conducting this experiment. The first group was for positive control (Vitamin C, ascorbic acid), the second group was of Panax ginseng (10 mg/kg body weight) treated group after bio-activity assay, the third group was of mercuric chloride treated group (0.033 mg/kg body weight) based on calculating $LD_{50}$ 9.26 mg/kg body weight by probit analysis, the fourth group was of mercuric chloride (0.033 mg/kg body weight) followed by Panax ginseng (10 mg/kg body weight) and the fifth group was Panax ginseng (10 mg/kg body weight) followed by mercuric chloride (0.033 mg/kg body weight) treated group. The interval between intake of Panax ginseng and mercuric chloride was of 2 hours in groups, fourth and fifth respectively. Comparative free radical scavenging property of Panax ginseng was studied under three in vitro models (role model for calculating scavenging activity) viz. DPPH method (hydroxyl free radicals), Nitric oxide method (nitrile free radicals) and Lipid peroxidation (mercury free radicals).