• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.281-286
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• 2019

Raman spectra of a-C:H thin films deposited with an unbalanced magnetron sputtering system showed that the G peak shifted to a higher wavenumber as the target power density increased and $I_D/I_G$ ratio increased from 0.902 to 1.012. Moreover, the transmittance of a-C:H films fabricated at 60 nm tended to decrease with increasing target power density; at 550 nm in the visible light region, the transmittance decreased from 69% to 58%. The rms surface roughness values of the a-C:H thin films decreased with increasing target power density, and varied from 1.11 nm to 0.71 nm. In order to achieve efficient light trapping, the light scattering at the rough interface must be enhanced. Consequently, the surface roughness of the thin film will decrease with the target power density. Further, the refractive index and reflectivity of the a-C:H thin films increased with increasing target power density; however, the Brewster angle decreased with the target power density. Hence, dye-sensitized solar cells using an a-C:H antireflective coating increased the CE, $V_{OC}$, and $J_{SC}$ by approximately 8.6%, 5.5%, and 4.5%, respectively.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.3
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• pp.89-94
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• 2019

K1A1 tank commander's primary thermal sight is a device that enables tank commanders to detect, identify, aim and track the target by observing targets in all directions during day, night and in situations of smokescreen and fog through $360^{\circ}$ rotation independent from the gunner's primary thermal sight and stabilizing the line of sight even under the vibrations occurring when the tank is standstill and moving. The main function of this device is to detect and process visible and thermal images and deliver the final images to the tank commander. One of the core parts to that end is the observation window (daytime/thermal image window). This core part is mounted at the entrance of the optical path for observing the target and plays the role of making visible light during the daytime and infrared light during the night pass through the target and transmitting the resultant images to the internal optical system of the tank commander's primary thermal sight. Such core parts have been selected as depot maintenance items so that they are replaced by new parts instead of being recycled when they are subjected to maintenance in most cases. That is, the military budget is wasted because such parts are replaced by new parts despite that they can be recycled for maintenance. Therefore, this study proposed a mounting tool for polishing and coating observation windows (daytime and thermal image window) using planar polishing equipment and DLC (Diamond-Like Carbon) coating equipment. In addition, this study presented an amendment (proposal) of the Depot Maintenance Work Request (DMWR) already published to verify the performance of recycled products including the establishment of inspection standards for recycling processes.

• Journal of the Korean institute of surface engineering
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• v.53 no.6
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• pp.293-299
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• 2020

The characteristics of the polycarbosilane (PCS)-based composite ceramic layer was studied by controlling the curing temperature. The stress at the interface of the graphite and SiOC composite layer was evaluated v ia finite element analysis. As a result, the tensile stress was released as the carbon ratio of the SiC decreases. In experiment, the SiOC layers were coated on the VDR graphite block by dip-coating process. It was revealed that the composition of Si and C was effectively adjusted depending on the curing temperature. As the solution-based process is employed, the surface roughness was reduced for the appropriate PCS curing temperature. Hence, it is expected that the cured SiOC layer can be utilized to reduce cracking and peeling of SiC ceramic composites on graphite mold by improving the interfacial stress and surface roughness.

• Journal of Electrochemical Science and Technology
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• v.13 no.1
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• pp.54-62
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• 2022

The preparation of low-cost, simple, and scalable electrodes is crucial for the commercialization of water electrolyzers for H₂ production. Herein, we demonstrate the fabrication of cathodes through Mo-modified Zn phosphating of Ni foam (NiF) for water electrolysis, which has been largely utilized in surface coating industry. In situ growth of electrocatalytically active layers in the hydrogen evolution reaction (HER) was occurred after 1 min of phosphating to form ZnNiMoP_i, and subsequent thermal treatment and electrochemical activation resulted in the formation of ZnNiMoPO_xH_y. ZnNiMoPO_xH_y exhibited superior HER performance than NiF, primarily because of the increased electrochemically active surface area of ZnNiMoPO_xH_y compared to that of bare NiF. Although further investigations to improve the intrinsic electrochemical activity toward the HER and detailed mechanistic studies are required, these results suggest that phosphating is a promising coating method and will possibly advance the fabrication procedure of electrodes for water electrolyzers with better practical applications.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.167-175
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• 1996

Work roll wear in the cold rolling of steel strip is strongly affected by rolling materials, rolling conditions and lubrication. Tests were performed to find the effects of rolling materials under the same lubricating conditions. Surface roughness of cold rolled steel strip as well as the coating technique itself is quite improtant in obtaining high image clarity of electronic products and car outer panels. Therefore this paper reviews for improvement of roughness and peak count about the surface of Cr coated work roll is investigated from the actual temper mill. The conclusions were obtained as follows; 1) Work roll wear in the cold rolling of steel strip is strongly affected by carbon contents of rolling materials, but there is not a separating force and total reduction ratio. 2) The roughness of strip surface is larger in the direction of width than in roll direction. 3) The electro-discharge textured roll has more uniform roughness distribu- tion than shot blasted roll and it's life time is two times longer than shot blasted because it has more harmonic wave roughness, and the higher peak count of surface roughness. 4) The life time of Cr coated work roll is 2 times longer than that of shot blasted work roll and variation of peak count, roughness and life time of Cr coated work roll is similar to electro-discharge texturing work roll. 5) The proper Cr coating thickness is 10 .mu. m at the work roll of temper mill.

• The Journal of the Korea Contents Association
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• v.14 no.2
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• pp.181-191
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• 2014

In the past, making IR photography needed somewhat complicated process, so its application fields were limited. However, it has become easy to make IR photography with advanced digital technology, so it is expected that the fields of IR photography and existing limit due to difficult making process will be expanded. Therefore, in this study, it is decided that the need of IR standard chart which allows us to manage exposure and tone of IR photography for scientific purpose will increase. Two methods were used to make IR standard chart. First method is to use aluminum. When aluminum has oxide coating through anodic oxidation, it has high durability, corrosion resistance and heat resistance. Also, IR reflectance of aluminum can be controlled in some degree depending on the thickness of oxide coating. Second method is to use pigments. Yellow 10P150 pigment is used for the brightest patch. This pigment is appropriate in this study due to high heat resistance and IR reflectance. Carbon black is used for the darkest patch. Carbon black absorbs much IR, and its color is not faded by any source of light. IR reflectance is adjusted elaborately by mixing two pigments. Finally, 6 patches are selected with consideration for actual IR reflectance of patches. As a result, IR reflectance of random subjects can be known approximately and IR photographs can have appropriate contrast with the IR standard chart.

• Analytical Science and Technology
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• v.17 no.6
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• pp.470-475
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• 2004

The mercury film thin layer flow cell (MFTLFC) which yielded the highest sensitivity for the electrochemical reduction of doxorubicin was constructed by coating the glassy carbon working electrode (GCE; $A=0.208cm^2$) with $5{\mu}L$ of HgO coating solution (0.5% HgO + 0.25% polystyrene/cyclohexanone) and subsequently followed by applying a potential of -0.40 V for 300 sec in the flow stream of an acetate buffer of pH 4.5. The voltammogram of doxorubicin reached the diffusion current plateau at -0.53 V vs. a Ag/AgCl (3 M NaCl) in the MFTLFC. The diffusion current (Id) of doxorubicin at the MFTLFC was 1.7 times greater than the Id obtained at the TLFC employing a bare glassy carbon working electrode. When the peak areas (electric charge) were plotted vs. concentrations of standard anthracyclines, the calibration factors of doxorubicin and daunorubicin were $1.12{\times}10^8{\mu}C/M$ (coefficient of determination; $R^2$: 0.969) and $0.98{\times}10^8{\mu}C/M$> ($R^2$: 0.999), respectively in the concentration range between $1.0{\times}10^{-8}M$ and $1.0{\times}10^{-6}M$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.7-11
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• 2022

Recently, Hanmi Gemological Institute & Laboratory (HGI) had an opportunity to examine 5 transparent synthetic moissanite. The round brilliants ranged from 0.93 to 0.96 ct and had a colorless, pink, yellow, blue, and red color. Advanced testing results, including Fourier-transform infrared (FTIR) and Raman spectroscopy, identified all the specimens as synthetic moissanite. Under the microscope, all samples except the colorless were confirmed to be a synthetic moissanite coated with a colored film. EDXRF chemical analysis detected very weak X-ray fluorescence peak characteristics of Ca, Ti, and Co in the colored samples. These features were not detected in the colorless sample. Raman spectroscopy investigation was unable to detect the 1332 cm^-1 (produced by sp³ bonding of carbon atoms) or the ~1550 cm^-1 (produced by graphite-related sp² bonding) peak in the colorless sample. The SEM image of the colorless sample showed no indication of a coating. The TEM image of the colorless sample revealed the presence of a 3~8 nm thick layer on the moissanite. Moreover, from the corresponding STEM Z-contrast image combined with the energy-dispersive X-ray spectroscopy (EDX) line profiles and EDX elemental maps, this layer was estimated to be carbon, silicon and oxygen.

• Science of Emotion and Sensibility
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• v.27 no.1
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• pp.59-68
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• 2024

This study aimed to develop a soft fabric-based elbow-bending angle sensor that can replace conventional hard-type inertial sensors and a system for estimating bending angles using it. To enhance comfort during exercise, this study treated four fabrics (Bergamo, E-band, span cushion, and polyester) by single-walled carbon nanotube dip coating to create conductive textiles. Subsequently, one fabric was selected based on performance evaluations, and an elbow flexion angle sensor was fabricated. Gauge factor, hysteresis, and sensing range were employed as performance evaluation metrics. The data obtained using the fabricated sensor showed different trends in sensor values for the changes in the angle during bending and extending movements. Because of this divergence, the two movements were separated, and this constituted the one-step process. In the two-step process, multilayer perceptron (MLP) was employed to handle the complex nonlinear relationships and achieve high data accuracy. Based on the results of this study, we anticipate effective utilization in various smart wearable and healthcare domains. Consequently, a soft- fabric bending angle sensor was developed, and using MLP, nonlinear relationships can be addressed, enabling angle estimation. Based on the results of this study, we anticipate the effective utilization of the developed system in smart wearables and healthcare.

• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.112-117
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• 2016

The standard(KS D 3631) should be obey for using fuel gas pipe in Korea and a carbon steel pipe is coated with synthetic resine for protecting the corrosion. The coating is just performed for anti-corrosion, and actual strength of pipe is given by the carbon steel pipe when the fuel gas is transported. When the flaws are occurred in the steel pipe, the estimation method which is used for residual strength is necessary. But the suitable method is not exist for applying the fuel gas pipe. Eventually, the residual strength is estimated by overseas regulation such as ASME B31G or DNV RP F101. But the method based on the relative regulations are not sufficiently valid and it can not estimate the 85% over even. Therefore, the test was performed for validation with pipe specimen. The specimen was made with artificial flaw. The test results showed the certain differences according to flaw depth and DNV RP F101 is suitable to estimate the residual strength in Korea. The results in this paper contain in case of the severe flaw depth and suitable mode for Korea, so the result can be expected as valuable and widely used in various field.