• Journal of Hydrogen and New Energy
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• v.7 no.2
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• pp.157-164
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• 1996

The AB5-type metal hydride electrodes using $(LM)Ni_{4.49}Co_{0.1}Mn_{0.205}Al_{0.205}$(LM : Lanthaniumrich Mischmetal) alloy powders(${\leq}200$mesh) which were coated with 25wt% copper in an acidic bath were prepared with or without addition of 10wt% PTFE as a binder. Prior to electrochemical measurements, the electrodes were sintered at $40^{\circ}C$ for 1 and 2hrs in vacuum with Mm(mischmetal) and sponge type Ti getters. The properties such as maximum capacity, cycle life and mechanical strength of the negative electrode have been investigated. The surface analysis of the electrode was also obtained before and after charge-discharge cycling using scanning electron microscope(SEM). From the observations of electrochemical behavior, it was found that the sintered electrode shows a lower maximum discharge capacity compared with non-sintered electrode but it shows a better cycle life. For the both electrodes with or without addition of PTFE binder, the values of mechanical strength were obtained, and their values increased with increasing sintering time. However, there is little difference of discharge capacity for both electrodes.

• Journal of the Korean Ceramic Society
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• v.45 no.10
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• pp.610-617
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• 2008

Multi-walled carbon nanotube(CNT) reinforced hydroxyapatite composite coating with a thickness of $5{\mu}m$ has been successfully deposited on Ti substrate using aerosol deposition(AD). The coating had a dense microstructure with no cracks or pores, showing good adhesion with the Ti substrate. Microstructural observation using field-emission scanning electron microscopy(FE-SEM) and transmission electron microscopy(TEM) showed that CNTs with original tubular morphology were found in the hydroxyapatite-CNT(HA-CNT) composite coating. Measurements of hardness and elastic modulus for the coating were performed by nanoindentation tests, indicating that the mechanical properties of the coating were remarkably improved by the addition of CNT to HA coating. Therefore, HA-CNT composite coating produced by AD is expected to be potentially applied to the coating for high load bearing implants.

• Journal of the Korea Fashion and Costume Design Association
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• v.16 no.3
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• pp.1-13
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• 2014

This study investigated body type among women in their 20s and the development of prototypes for tailored jackets by body type in order to design clothes in consideration of an imbalance in body type caused by the popularity of portable devices such as smartphones and Netbooks. This study aims to create a design of jacket patterns by body type through both actual and virtual wear testing among women in their 20s, who are the major consumer of ready-made clothes and are very sensitive to size fit. This study will provide pattern information for the manufacture of jackets with a goal of securing the latest scientific body type information and establish the grounds for a research method in the manufacture of clothes. According to actual and virtual wear tests of four different body types, a significant difference was found in armhole circumference in most types because it was scanned with the arms slightly apart to prevent the armhole area from being missed during the 3D scanning. This has resulted in a slight distortion in measurements. To correct this problem, it is necessary to verify the precision of the body scanner and its program. In categories in which a large significant difference was found, it is necessary to test them against many subjects. In addition, it would be required to perform a further study on the 3D virtual wear system, which could be useful in the clothing industry.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.11 s.353
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• pp.14-18
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• 2006

Optical interferometer is used for various optical measurement fields in optical metrology and biomedical measurements. In an optical interferometer, optical delay line has to change the optical path length of a reference arm to match with that of a sample in and it's speed was limited by reference arm movement speed. In this paper, we proposed an all-fibered RSODRapid Scanning-speed Optical Delay) without any mechanical movement, and we applied this system to optical interferometer. Experimental setup is consist of pulse laser source (center wavelength 1304nm, pulse width 30ps, repetition rate 10GHz), two phase modulators and dispersive shifted fiber. As experimental results, we obtain the maximum time delay of 11ps at 10MHz repetition rate, and it is easily tuneable the time delay by modulation frequency and modulation voltage.

• Journal of the Korean Electrochemical Society
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• v.2 no.2
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• pp.61-65
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• 1999

A new treatment of $LiV_3O_8$ has been proposed for improving its electrochemical behavior as a cathode material for secondary lithium batteries. Lithium trivanadate, $LiV_3O_8$, can be prepared in a finely dispersed form by dehydration of aqueous lithium trivanadate gels. The ultrasonic treatment method for Liv30s has been examined in comparison with $LiV_3O_8$ prepared by solutionmethod. The ultrasonically treated products in water were characterized by XRD (X-ray diffractometry), TGA (thermogravimetric analysis) and SEM (scanning electron microscopy). These measurements showed that the ultrasonic treatment process of aqueous $LiV_3O_8$ caused a decrease in crytallinity and considerable increased in specific surface area and interlayer spacing. The product, ultrasonically treated in water for 2 h, showed a high initial discharge capacity and was charge-discharge cycled without large capacity loss. The ultrasonic treated Liv30s can improve not only the specific capacity, but also the cycling behavior

• Journal of Electrochemical Science and Technology
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• v.11 no.4
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• pp.368-378
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• 2020

In the paper, corrosion behavior of T91 steel in different concentrations of NaHSO₃ solution was studied in combination with scanning electron microscope (SEM) and electrochemical measurements. The results showed that the steel exhibited active anodic dissolution characteristics in the solution, and NaHSO₃ concentration affected both cathodic and anodic behaviors. The steel surface was covered by intact corrosion products in the solutions, but the compactness and mechanical properties of the corrosion products degraded with the increase of NaHSO₃ concentration. In low-concentration NaHSO₃ solution the steel tended to undergo uniform corrosion with slight corrosion pits, but its corrosion mode gradually transited to localized corrosion as the NaHSO₃ concentration increased. The mechanical property degradation of the corrosion products caused by sulfur compounds and the pH decrease of the solution are the important factors to accelerating its corrosion process.

• Journal of The Korean Astronomical Society
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• v.38 no.4
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• pp.437-443
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• 2005

The Solar Radio Burst Locator (SRBL) is a spectrometer that can observe solar microwave bursts over a wide band (0.1-18 GHz) as well as detect the burst locations without interferometry or mechanical scanning. Its prototype has been operated at Owens Valley Radio Observatory (OVRO) since 1998. In this study, we have evaluated the capability of the SRBL system in flux and radio burst location measurements. For this, we consider 130 microwave bursts from 2000 to 2002. The SRBL radio fluxes of 53 events were compared with the fluxes from USAF/RSTN and the burst locations of 25 events were compared with the optical flare locations. From this study, we found: (1) there is a relatively good correlation (r = 0.9) between SRBL flux and RSTN flux; (2) the mean location error is about 8.4 arcmin and the location error (4.7 arcmin) of single source events is much smaller than that (14.9 arcmin) of multiple source events; (3) the minimum location error usually occurred just after the starting time of burst, mostly within 10 seconds; (4) there is a possible anti-correlation (r = -0.4) between the pointing error of SRBL antenna and the location error. The anti-correlation becomes more evident (r=-0.9) for 6 strong single source events associated with X-class flares. Our results show that the flux measurement of SRBL is consistent with that of RSTN, and the mean location error of SRBL is estimated to be about 5 arcmin for single source events.

• Bulletin of the Korean Chemical Society
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• v.35 no.12
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• pp.3576-3582
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• 2014

Zeolite-templated carbons (ZTCs), which have high specific surface area, were prepared by a conventional templating method using microporous zeolite-Y for catalyst supports in direct methanol fuel cells. The ZTCs were synthesized at different temperatures to investigate the characteristics of the surface produced and their electrochemical properties. Thereafter, Pt-Ru was deposited at different carbonization temperatures by a chemical reduction method. The crystalline and structural features were investigated using X-ray diffraction and scanning electron microscopy. The textural properties of the ZTCs were investigated by analyzing $N_2$/77 K adsorption isotherms using the Brunauer-Emmett-Teller equation, while the micro- and meso-pore size distributions were analyzed using the Barrett-Joyner-Halenda and Harvarth-Kawazoe methods, respectively. The surface morphology was characterized using transmission electron microscopy and inductively coupled plasma-mass spectrometry. The electrochemical properties of the Pt-Ru/ZTCs catalysts were also analyzed by cyclic voltammetry measurements. From the results, the ZTCs carbonized at $900^{\circ}C$ show the highest specific surface areas. In addition, ZTC900-PR led to uniform dispersion of Pt-Ru on the ZTCs, which enhanced the electro-catalytic activity of the Pt-Ru catalysts. The particle size of ZTC900-PR catalyst is about 3.4 nm, also peak current density from the CV plot is $12.5mA/cm^2$. Therefore, electro-catalytic activity of the ZTC900-PR catalyst is higher than those of ZTC1000-PR catalyst.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.1 s.55
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• pp.29-33
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• 2006

This article describes an enzyme stabilization method that allows the use of enzymes irrespective of environmental factors, especially heat, while maintaining their activity for a long time. We have designed enzyme microcapsules that consist of papain enzyme cores, poly(propylene glycol) interlayers, and poly(${\epsilon}-caprolactone$) walls. By confocal laser scanning microscopy measurements and the thermal stability of papain-loaded microcapsules, it is demonstrated that the papain is surrounded by a hydrophobic polyol layer and stabilized by the exclusive volume effect. In our study, improved thermal stability can be obtained by using more hydrophobic long-chained polyols, which is understood to be attributed to the effective formation of a hydrophobic polyol layer between the papain and the polymer wall by means of conformational anchoring in the interface.

• Applied Chemistry for Engineering
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• v.28 no.2
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• pp.245-251
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• 2017

In this study, ZnO, which is widely known as a non $TiO_2$ photocatalyst, was synthesized using coprecipitation method and Ag was added in order to improve the catalytic performance. The physicochemical characteristics of the synthesized ZnO and Ag/ZnO particles were checked using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), photoluminescence (PL), and photocurrent measurements. The performance of catalysts was tested by $H_2$ production using the photolysis of $H_2O$ with MeOH. By adding Ag which plays a role as an electron capture on the ZnO catalyst, the performance increased due to the recombination of excited electrons and holes. In particular, $8.60{\mu}mol\;g^{-1}$ $H_2$ was produced after 10 h reaction over the 0.50 mol% Ag/ZnO.