• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.943-946
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• 1997

Electropolishing is the controlled electrochemical removal of surface metal, resultmg in a brilliant appearance andimproved properties. Sometimes described as "reverse plating," the process has a leveling effect, which produces smoothnessand increased reflectivity. Unlike conventional mechanical finishing systems, the electropolishing does not smear, bend,stress or fracture the crystalline metal surface to achieve smoothness. Instead, electropolishing removes metal from thesurface producing a unidirectional pattern that is stress-free, microscopically smooth and often highly reflective. In addition,improved corrosion resistance and passivity are achieved on many ferrous and some non-ferrous alloys. Pure aluminium doesnot electropolish well, if at all, but most other alloys of aluminum electropolish excellently.Therefore, the aim of this study is to determine the characteristics of electropolishing aluminium alloy in term of currentdensity, machining time, temperature, electrode gap and workpiece surface measurementkpiece surface measurement

• Solar Energy
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• v.6 no.2
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• pp.70-75
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• 1986

The fabrication procedure and characteristics of $Ta_2O_5/Al/SiO_2/p-Si$ MIS solar cells forming a fine grating pattern of aluminum evaporated on to p-type silicon crystal are discribed. The proper temperature for oxide growing of these cells was found to be about $450^{\circ}C$ for 20 minutes with oxygen flow. The conversion efficiency increased about 3% after $750{\AA}$ thickness of tantalium silica film spin on anti-reflective coating. The best results showed that $V_{oc}=0.545V,\;J_{sc}=34mA$ and F.F = 0.65, which represent that the conversion efficiency is 12%.

• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.102-107
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• 2021

In this paper, the measurements of received power was shown and compared in two developed 5.8GHz 25W wireless charging systems. One is the system using commercial transmission antenna, and the other is the system using transmission antenna combined with metamaterial. The system combined with metamaterial shows higher received power due to negative reflective index of metamaterial. In addition, a comparative analysis of the systems shows that the transmission efficiency in the systems can decrease the real gain of transmission antenna due to higher side robe of beam pattern. The side robe beams of transmitting antenna interferes transmitted beam with the reflected beams from the bottom region due to the side robes. The failure problems of the RF wireless charging systems are discussed and proposed in order to charge mobile devices through the RF wireless charging system.

• Polymer(Korea)
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• v.31 no.2
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• pp.148-152
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• 2007

The prototype of color fitters for the liquid crystal displays (LCD) using cholesteric liquid crystal monomers was produced. Cholesteric liquid crystal is characterized by the unique optical features of selective reflection, which is due to the helical twisting structures of LCs comparable to the wavelength of the incident light under certain conditions of substrate treatment. In the results of the experiment, cholesteric films for red, green, and blue light reflections respectively were produced and the viewing angle dependence of these films were investigated. Reflective light of red and green films shifted to shorter wavelength regions as viewing angle becomes greater, but blue one shifted very little. Periodic micrometer-sized half-spherical photoresist formed by thermal reflow method after photo-lithography was patterned on glass substrates. The viewing angle dependence of reflective light colors of red, green, and blue films on the patterned substrates compared with those on no patterned substrates was investigated. We could confirm the dependences were much smaller on the patterned substrates by bare eyes and Lab-color coordination methods qualitatively.

• 한국노년학
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• v.39 no.3
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• pp.613-633
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• 2019

The purpose of this research is to analyze the subjective perception pattern of Good Death of the Elderly by using Q-methodology. The researcher conducted individual in-depth interviews of 9 people, 4 times FGI and literature reviews to collect self-reflective statements about good death and dying. The interviewees were death-related workers, people who had experience with death of their spouse or parents, experts and the elderly through individual or group interviews. Thirty-four Q-samples were extracted from the Q-population and P-samples of thirty people male and female 15 each from sixties to eighties participated in Q-sorting. Data analysed using by QUANL program and found that three factor structures were appropriate accounted for 54.64% of the total variance. Perception pattern on Good Death was analysed into 3 types; Death without fear(type 1), Burdenless death(type 2), Long-lived-death(type 3). According to these results, the researcher discussed theoretically and suggested some significant implications.

• Fashion & Textile Research Journal
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• v.18 no.4
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• pp.498-508
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• 2016

The purpose of this study is to develop an aesthetic and functional bicycle wear for new senior women in their 50s and 60s. Based on the results of the survey, we developed bicycle wear that is friendly to bicycling posture and reflects the preference of new senior women. The results are as followed: First, emphasis is placed on the simple and functional design of the experimental wear consisting of jacket and pants. Jacket is different from the color scheme with the armhole princess line in order for the waistline to look slim. Pants are designed to hold the leg muscles tightly in order to help reduce the muscle fatigue on the bicycle ride. Second, cutting lines and coloring materials are used for the wearer to look slim and the safety of the wearer is planned to secure by inserting the reflective material along the cutting lines on the bicycle ride. Third, the pattern of the experimental wear is designed in consideration of the riding motion of the bicycle. Jacket is designed to have back length longer than front length as compared to the bicycle wears available on the market. Sewing lines in the armpit are designed to be eliminated in order to move the arms smoothly on the ride. Pants are designed to minimize the seam line in consideration of the movement of muscles and ligaments and the experimental wear is produced by combining the material with the functions of cool comfort and stretch.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.3
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• pp.380-393
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• 2015

This study presents how we can evaluate stereo camera systems for the structural deformation monitoring. A stereo camera system, consisting of a set of stereo cameras and reflective markers attached on the structure, is introduced for the measurement and the stereo pattern recognition (SPR) method is utilized for the full-field structural deformation estimation. Performance of this measurement system depends on many parameters including types and specifications of the cameras, locations and orientations of them, and sizes and positions of markers; it is difficult to experimentally identify the effects of each parameter on the measurement performance. In this study, a simulation framework for evaluating performance of the stereo camera systems with various parameters has been developed. The maximum normalized root-mean-square (RMS) error is defined as a representative index of stereo camera system performance. A plate structure is chosen for an introductory example. Its several modal harmonic vibrations are generated and estimated in the simulation framework. Two cases of simulations are conducted to see the effects of camera locations and the resolutions of the cameras. An experimental validation is carried out for a few selected cases from the simulations. Using the simultaneous laser displacement sensor (LDS) measurements as the reference, the measurement errors are obtained and compared with the simulations.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.3
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• pp.410-419
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• 2009

The purpose of this study was to develop the functionally improved winter work clothing for the Korean railroad workers. Based on the questionnaires, sample clothing for the Korean railroad workers was produced. The design, materials, and patterns were modified to increase mobility and comfort for workers. Water-repellent treatment was added to the material in order to decrease the dirt and stains while working. Also, reflective strips were added to side seams and hems of the trousers in order to increase the visibility and safety of the workers. In terms of the design and pattern, a circumference of 4.5cm was added to the crotch area in order to minimize tightness on the hip and crotch areas, but no additional circumference was added to the hip area. And a 1cm width dart was inserted between the side seams and yoke in order to add activity. Also three 1.4cm width tucks were used at 2.5cm space on the knees to alleviate tightness at the knees. The prototype was evaluated objectively and subjectively to compare with the existing working uniform. The assessment group consisted of 5 subject groups and 11 expert groups to evaluate external appearance and adaptability of the movements. Subject and panels were asked to evaluate the prototype that followed an ergonomic design and pattern. According to the results, the prototype was evaluated better than the existing working uniform in appearance and adaptability. A field test was conducted to compare the prototype and the existing working uniform. The field tests were performed by 6 workers in the Korean railroad. According to the results, the prototype advanced in terms of adaptability and comfort.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.105-108
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• 2005

The radiated noise from the automotive intake system should be predicted at the design stage. To this end, the precise measurement of in-duct acoustic source parameters of the intake system, i.e., the source strength and source impedance, is essential. Most of previous works on the measurement of acoustic source parameters were performed under a fixed engine speed condition. However, the requirement of vehicle manufacturer is the noise radiation pattern as a function of engine speed. In this study, the direct method was employed to measure the source parameters of engine intake system under a fixed engine speed and engine run-up condition. It was noted that the frequency spectra of source impedance hardly changes with varying the engine speed. Thus, it is reasonable to calculate the source strength under the engine run-up condition by assuming that source impedance is invariant with engine speed. Measured and conventional source models, i.e., constant pressure source, constant velocity source, and non-reflective source, were utilized to predict insertion loss and radiated sound pressure level. A reasonable prediction accuracy of radiated sound pressure level spectra from the intake system was given in the test vehicle when using the measured source characteristics which were acquired under the operating condition.

• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.159-163
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• 2014

More accurate CD (Critical Dimension) control is required for the nanometer-scaled devices. However, since the reflectivity between substrate and PR (Photoresist) becomes higher, the CD (Critical Dimension) swing curve was intensified. The higher reflectivity also causes PR notching due to the pattern of sub-layer. For this device requirement, it was optimized for the thickness, refractive index(n) and absorption coefficient(k) in the bottom anti-reflective coating(BARC; SiON) and photoresist with the minimum reflectivity. The computational simulated conditions, which were determined with the thickness of 33 nm, n of 1.89 and k of 0.369 as the optimum condition, were successfully applied to the experiments with no standing wave for the 0.13um-device. At this condition, the lowest reflectivity was 0.44%. This optimum condition for BARC SiON film was applied to the process for 0.13um-device. The optimum SiON film as BARC to PR and sub-layer could be formed with the accurate CD control and no standing waver for the nanometer-scaled semiconductor manufacturing process.