• Journal of the Korean Home Economics Association
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• v.44 no.2 s.216
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• pp.93-101
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• 2006

Children's wear needs extra safety features to avoid unexpected dangers. On the way to school, children are exposed to traffic very often. Especially in the early morning or late evening, or on dark cloudy days, they might be unrecognized by drivers without safety reflectors on their clothing as a means of raising visibility. Therefore, safety reflectors on clothing can protect children from traffic accidents. The research was carried out as follows. 1. Reflector manufacturers were interviewed regarding how Reflective and Reflexite reflect light back to the light source, what kind of safety reflector products are available, and how these materials are being used in the clothing industry. 2. Mothers of primary school children were interviewed to find out what they think about the effect of safety reflectors, the need for clothing using safety reflectors and the design preferences. 3. In order to apply safety reflectors efficiently, the position on the clothing of the greatest visibility from the light source must be determined. 4. Shirts, pants and jumpers for 8-year-old girls and boys were designed as a case study of applying safety reflectors to clothing. The designs were verified through wearing test.

• Journal of the Korean Society for Nondestructive Testing
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• v.5 no.2
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• pp.34-41
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• 1986

The ultrasonical characteristics of inclined planar reflectors is investigated by the maximum amplitude method. The reflected ultrasound is varied by the reflector size, shape, inclination and using transducers. It was found that the detecting ability for planar reflectors was decreased with increasing transducer size and misorientation angle and increased with decreasing ultrasonic frequency, also the misorientation angle of planar reflectors affected significantly for the measurement of refklector size.

• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.408-412
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• 2012

An in-line dispersive delay line (DDL) demands low and controllable reflectivity of the reflectors, especially if the surface acoustic wave (SAW) propagates all the way along the reflecting structure. The metal reflectors are usually too strong and introduce too much attenuation in such a device. The proposed solution of this problem is to spatially separate the acoustic channels for different frequencies with the help of Fan-shaped Transducers (FIDT) and to use narrow open metal reflectors to reduce reflectivity. Special arrangement of FIDT is performed to use 180-deg. reflection of the SAW. Narrow open metal strips with a metallisation ratio of the order of 20% are used as reflectors with small and controllable reflectivity. Reflectivity of such strips is estimated both theoretically and experimentally. Experimental performance of the proposed DDL is presented.

• Journal of information and communication convergence engineering
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• v.1 no.4
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• pp.199-204
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• 2003

In this paper, we present the thermal annealing effects of the W/$SiO_2$ multi-layer reflectors in ZnO-based FBAR devices with cobalt (Co) electrodes in comparison with those with aluminum (Al) electrodes. Various thermal annealing conditions have been implemented on the W/$SiO_2$ multi-layer reflectors formed on p-type (100) silicon substrates. The resonance characteristics could be significantly improved due to the thermal annealing and were observed to depend strongly on the annealing conditions applied to the reflectors. Particularly, the FBAR devices with the W/$SiO_2$ multi- layer reflectors annealed at $400^{\circ}C$/30min have shown superior resonance characteristics in terms of return loss and quality-factor (Q-factor). In addition, the use of Co electrodes has resulted in further improvement of the resonance characteristics as compared with the Al electrodes. As a result, the combined use of both the thermal annealing and Co electrodes seems very useful to more effectively improve the resonance characteristics of the FBAR devices with the W/$SiO_2$ multi-layer reflectors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1238-1244
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• 2011

This paper presents the matching method of reflectors for localization of laser navigation. The laser navigation is a device that measures distance and angle of reflector. The conventional major matching using the laser navigation is method that moves position of measured reflectors to position of installed reflectors and than rotate moved reflectors. However, it is difficult to use the industry because it has high computational complexity and high errors. To solve those problem, The proposed matching is method that create position of measured reflectors to assume that the position of installed reflectors is position of AGV and than rotate the position of installed reflectors. For experiment, we used AGV which was designed by ourselves, and compared positioning accuracy when AGV moves according to varying steering angle and driving speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.87-91
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• 2005

The effects of the movable reflectors on the stage acoustics in Seoul's Sejong Performing Arts Center (3,048-seat multi-purpose hall, stage area of $270m^2$ within an orchestra shell) and Ceramic Palace Hall (440-seat concert hall, stage area of $105m^2$) were investigated. Acoustical parameters were evaluated by measuring stage and audience acoustics in the two halls. The study was primarily based on the stage support parameter STI proposed by Gade (Acustica 65, pp.193-203, 1989). Results showed that STI varied on the stage of the large hall according to the position of the reflectors, whereas STI did not vary in the small hall. In the large hall, a smaller clear stage area (bounded by the reflectors) yields an increase in both STI and other early energy measures. In the small hall, early energy decreases when its stage's surface diffusion was covered with specular reflectors.

• Journal of information and communication convergence engineering
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• v.1 no.3
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• pp.129-132
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• 2003

In this paper, cobalt (Co)-electrode FBAR devices fabricated on seven-layered Bragg Reflectors are presented along with their resonance characteristics. ZnO films are used as the resonating material in FBAR devices where the Co electrode is 3000${\AA}$ thick. All processes are preformed in an RF magnetron sputtering system. As a result of characterization, the resonance characteristics are observed to depend strongly on the quality of ZnO film and Bragg Reflectors. In addition, the FBAR devices with W/$SiO_2$ reflectors show good resonance characteristics in term of return loss and quality-factor (Q-factor).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.381-384
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• 2003

In this paper, cobalt (Co)-electrode FBAR devices fabricated on seven-layered Bragg Reflectors are presented along with their resonance characteristics. ZnO films are used as the resonating material in FBAR devices where the Co electrode is 3000$\AA$ thick. All processes are preformed in an RF magnetron sputtering system. As a result of characterization, the resonance characteristics are observed to depend strongly on the quality of ZnO film and Bragg Reflectors. In addition, the FBAR devices with W/SiO$_2$ reflectors show good resonance characteristics in term of return loss and quality-factor (Q-factor).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.633-636
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• 2003

In this work, We, for the first time, present the effects of the thermal annealing of the W/SiO$_2$ multi-layer quarter wavelength reflectors on the resonant properties of the ZnO-based SMR devices. In order to improve the resonant properties of the SMR devices, we annealed thermally the reflectors formed on a silicon substrate using a RF magnetron sputtering technique. As a result, the resonant properties of the SMR devices were observed to strongly depend on the annealing conditions applied to the reflectors. The SMR devices with the reflectors annealed at 40$0^{\circ}C$/30min showed excellent resonance properties as compared to those with the reflectors non-annealed (as-deposited). The newly proposed simple thermal annealing process will be very useful to more effectively improve the resonant properties of the future SMR devices with W/SiO$_2$ multi-layer quarter wavelength reflectors.

• Journal of Biosystems Engineering
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• v.34 no.4
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• pp.260-268
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• 2009

As a basic study to develop a high sensitive biosensor using film bulk acoustic resonator, the mathematical model for analyzing the resonance characteristics of bulk acoustic resonator with acoustic Bragg reflectors was investigated. The simulation results due to the number of acoustic Bragg reflectors with low and high acoustic impedance materials were compared with the experimental results for 1, 2.25 and 5 MHz of PZT based bulk acoustic resonators with various acoustic Bragg reflectors. At the fabricated bulk acoustic resonator with an odd number of acoustic Bragg reflectors, low and high acoustic impedance materials in sequence under the bottom electrode showed better resonance characteristics than even number of acoustic Bragg reflectors. The changes of resonance frequencies due to the increase of number of acoustic Bragg reflectors by simulation and experiment, respectively showed approximately similar tendency but some differences in input impedance between the experiment and simulation were found. The derived mathematical model for describing the resonance characteristics of the bulk acoustic resonator with acoustic Bragg reflector will be available for analyzing the design parameters for development of biosensor using bulk acoustic resonator.