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Development of a Piezoelectric Ultrasonic Tooth-whitening Apparatus
Lee, Young-Jin,Paik, Jong-Hoo,Lee, Jeong-Bae,Choi, Seung-Jae The Korean Institute of Electrical and Electronic 2013 Transactions on Electrical and Electronic Material Vol.14 No.5
The aim of this study was to develop an ultrasonic tooth-whitening apparatus using piezoelectric transducers, which enhance bleaching efficiency by applying ultrasound, while performing a teeth whitening procedure. For this purpose, an ultrasonic transducer was designed and manufactured, and the effects of reduction in the whitening material's concentration and in the whitening treatment time through using the ultrasound cavitation phenomenon were confirmed. Also, the validity of this study was investigated by comparing the whitening performance with a commercialized optical whitener, through color comparison. The results revealed that the ultrasound whitener produced color values that were enhanced by as much as double that of the conventional LED light whitening method. Even when the operational time was reduced by half, the ultrasound method showed superior performance by over 54% compared to the conventional light whitener, revealing that the ultrasound method showed a remarkable treatment reduction effect.
Development of Miniature Quad SAW Filter Bank based on PCB Substrate
이영진,Chang-Il Kim,Jong-Hoo Paik 한국전기전자재료학회 2008 Transactions on Electrical and Electronic Material Vol.9 No.1
This paper describes the development of a new 5.0×3.2 mm SAW filter bank which is consist of 12 L, C matching components and 4 SAW bare chips on PCB substrate with CSP technology. We improved the manufacturing cost by removing the ceramic package through direct flip bonding of LiTaO₃ SAW bare chip on PCB board after mounting L, C passive element on PCB board. After that we realized the hermitic sealing by laminating the epoxy film. To confirm the confidentiality and durability of the above method, we have obtained the optimum flip bonding & film laminating condition, and figured out material property and structure to secure the durability & moisture proof of PCB board. The newly developed super mini 5.0×3.2 mm filter bank shows the superior features than those of existing products in confidence, electrical, mechanical characters.
Class I Flextensional 변환기의 주파수 특성 변화
강국진,백종후,이영진,Kang, Kook-Jin,Paik, Jong-Hoo,Lee, Young-Jin 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.2
We constructed a Class I flextensional transducer, and analyzed the variation of the resonance frequency of the transducer in relation to its structural and material variables. We used the FEM for the analysis. Total length of the transducer, thickness and material properties of the shell have large effects on the resonance frequency. While outer radius of the ceramic stack and material properties of the ceramic stack have no effect on the resonance frequency. In addition, the validation of the FE model was verified by manufacturing and comparison of the impedance analysis. Results of the present work can be utilized to design a Class I flextensional transducers of various resonance frequency.
Ji, Sang Hyun,Cho, Jeong Ho,Paik, Jong-Hoo,Yun, Jondo,Yun, Ji Sun Elsevier 2017 Sensors and actuators. A, Physical Vol.263 No.-
<P><B>Abstract</B></P> <P>This study investigates the poling effects on the performance of a lead-free piezoelectric nanofiber module. The lead-free piezoelectric nanofiber of 0.78Bi<SUB>0.5</SUB>Na<SUB>0.5</SUB>TiO<SUB>3</SUB>-0.22SrTiO<SUB>3</SUB> (BNT-ST) and polyvinylidenefluoride (PVDF) is prepared by an electrospinning, and the lead-free piezoelectric nanofiber modules are fabricated with the bottom and top interdigitated electrodes. The poling effects on the performance of the lead-free piezoelectric nanofiber module were investigated by XRD and temperature-dependence dielectric properties. The possibility of a flexible structural health monitoring sensor application is confirmed by measuring the output voltage of the poled and unpoled lead-free piezoelectric nanofiber modules. The flexible lead-free piezoelectric nanofiber modules are directly attached on the structure with various shapes. We expect that this system will improve the efficiency of sensing. Tests on impact detection and the structural health monitoring based on the poled and unpoled lead-free piezoelectric nanofiber modules were carried out. The monitoring results confirm the potential for estimating impact location and problems with the structure, which have been observed more obviously in the poled lead-free piezoelectric nanofiber modules.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This study investigates poling effects on the performance of a lead-free piezoelectric nanofiber module. </LI> <LI> The poling effects on the sensor characteristics of the lead-free piezoelectric nanofiber module were investigated by simulating several situations. </LI> <LI> The flexible lead-free piezoelectric nanofiber modules are directly attached on the structure with various shapes. </LI> <LI> The monitoring results confirm the potential for estimating impact location and problems with the structure. </LI> <LI> The poling process contributed greatly to the improvement of the sensing performance. </LI> </UL> </P>
Lee, Ku-Tak,Choi, Boo-Hyun,Woo, Jong-Un,Kang, Jeong-Su,Paik, Jong-Hoo,Chu, Byoung-Uck,Nahm, Sahn Elsevier 2018 Journal of the European Ceramic Society Vol.38 No.12
<P><B>Abstract</B></P> <P>ZnS nanopowders annealed at low temperatures (≤550 °C) have a pure cubic structure, while a small amount of hexagonal phase formed in specimens annealed at temperatures ≥700 °C. The particle sizes of the ZnS nanopowders increased with the annealing temperature. ZnS ceramics that were sintered using ZnS nanopowders annealed at low temperatures (≤550 °C) exhibited low transmittance, because of their porous microstructure. ZnS ceramics that were synthesized using ZnS powders annealed at high temperatures (≥800 °C) containing large agglomerated particles, also exhibited low transmittance, due to the presence of a liquid phase. A carbonate absorption band was found from the ZnS ceramics with small grains, because carbon ions diffused from the graphite mold into the ZnS ceramics during sintering, probably through the grain boundaries, and formed carbonates. A ZnS ceramic that was sintered at 1020 °C using the nanopowders annealed at 750 °C exhibited dense microstructure, with a large transmittance, 68%, in the wavelength range 6.0–12 μm.</P>
Development of Miniature Quad SAW Filter Bank based on PCB Substrate
Lee, Young-Jin,Kim, Chang-Il,Paik, Jong-Hoo The Korean Institute of Electrical and Electronic 2008 Transactions on Electrical and Electronic Material Vol.9 No.1
This paper describes the development of a new $5.0{\times}3.2mm$ SAW filter bank which is consist of 12 L, C matching components and 4 SAW bare chips on PCB substrate with CSP technology. We improved the manufacturing cost by removing the ceramic package through direct flip bonding of $LiTaO_3$ SAW bare chip on PCB board after mounting L, C passive element on PCB board. After that we realized the hermitic sealing by laminating the epoxy film. To confirm the confidentiality and durability of the above method, we have obtained the optimum flip bonding & film laminating condition, and figured out material property and structure to secure the durability & moisture proof of PCB board. The newly developed super mini $5.0{\times}3.2mm$ filter bank shows the superior features than those of existing products in confidence, electrical, mechanical characters.