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Design of piezoelectric ocean-wave energy harvester using sway movement
Hwang, Won Seop,Ahn, Jung Hwan,Jeong, Se Yeong,Jung, Hyun Jun,Hong, Seong Kwang,Choi, Jae Yoon,Cho, Jae Yong,Kim, Jung Hun,Sung, Tae Hyun Elsevier Sequoia 2017 Sensors and actuators. A Physical Vol.260 No.-
<P><B>Abstract</B></P> <P>The use of energy harvesting technologies for supplying power generating energy to wireless devices and sensors, particularly in scenarios where it is difficult to exchange or recharge batteries, has recently attracted considerable research attention. In this context, we report the design of a piezoelectric energy harvesting system that can be used to harvest energy from the ocean. The harvester is composed of a piezoelectric cantilever structure and a magnet as the tip-mass of the piezoelectric module, atop which a rail (tube) with a metal ball is positioned. The system is tested with a setup that simulates ocean waves. Our findings indicate that our approach can be utilized in the design of multipurpose piezoelectric energy harvesting systems for low frequency vibration and in “sea-based” applications involving buoys and boats.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We design a piezoelectric ocean-wave energy harvester (POEH) that can harness wave energy. </LI> <LI> The POEH uses a ball-and-rail mechanism to induce cantilever vibrations. </LI> <LI> The POEH yields improved voltage and power output than cantilever system. </LI> <LI> Our device can be used for low-frequency energy harvesting applications. </LI> </UL> </P>
Dissolution behavior and early bone apposition of calcium phosphate-coated machined implants
Hwang, Ji-Wan,Lee, Eun-Ung,Lee, Jung-Seok,Jung, Ui-Won,Lee, In-Seop,Choi, Seong-Ho Korean Academy of Periodontology 2013 Journal of Periodontal & Implant Science Vol.43 No.6
Purpose: Calcium phosphate (CaP)-coated implants promote osseointegration and survival rate. The aim of this study was to (1) analyze the dissolution behavior of the residual CaP particles of removed implants and (2) evaluate bone apposition of CaP-coated machined surface implants at the early healing phase. Methods: Mandibular premolars were extracted from five dogs. After eight weeks, the implants were placed according to drilling protocols: a nonmobile implant (NI) group and rotational implant (RI) group. For CaP dissolution behavior analysis, 8 implants were removed after 0, 1, 2, and 4 weeks. The surface morphology and deposition of the coatings were observed. For bone apposition analysis, block sections were obtained after 1-, 2-, and 4-week healing periods and the specimens were analyzed. Results: Calcium and phosphorus were detected in the implants that were removed immediately after insertion, and the other implants were composed mainly of titanium. There were no notable differences between the NI and RI groups in terms of the healing process. The bone-to-implant contact and bone density in the RI group showed a remarkable increase after 2 weeks of healing. Conclusions: It can be speculated that the CaP coating dissolves early in the healing phase and chemically induces early bone formation regardless of the primary stability.
황대현,최형심,고은영,원형진,이재영,김현범,이인재,이관섭,이열,이일성,강익원,우영민,최창식,윤대원 대한혈관외과학회 2002 Vascular Specialist International Vol.18 No.1
A case of coil embolization in right superior thyroid artery pseudoaneurysm by stab wound is reported. A fifty-six-year old female, laceration and some bulging in right neck side. Aortic arch angiography, right common carotid angiography was done. Angiography shows 4×2 cm sized right thyroid artery pseudoaneurysm (FIg. 1) and (Fig. 2). We selected right superior thyroid artery by 3F micorofert (CooK, Bloomington, Ind.) and embolized by 2×4 mm (diameter), 2 cm (length) sized micro tornaido coil (CooK, Bloomington, Ind.). Post procedure right common carotid angiography was done. Angiography shows no visualized right thyroid artery pseudoaneurysm (Fig. 3).
Hwang, Ji-Hee,Lee, Ju-Hyung,Hwang, Jeong-Hwan,Chung, Kyung Min,Lee, Eun-Jung,Yoon, Yong-Joo,Moon, Mi-Kyoung,Kim, Ju-Sin,Won, Kyoung-Suk,Lee, Chang-Seop The Korean Academy of Medical Sciences 2015 JOURNAL OF KOREAN MEDICAL SCIENCE Vol.30 No.6
<P>Methicillin-resistant <I>Staphylococcus aureus</I> (MRSA) is a major cause of ear infections. We attempted to evaluate the clinical usefulness of arbekacin in treating chronic suppurative otitis media (CSOM) by comparing its clinical efficacy and toxicity with those of vancomycin. Efficacy was classified according to bacterial elimination or bacteriologic failure and improved or failed clinical efficacy response. Ninety-five subjects were diagnosed with CSOM caused by MRSA. Twenty of these subjects were treated with arbekacin, and 36 with vancomycin. The bacteriological efficacy (bacterial elimination, arbekacin vs. vancomycin: 85.0% vs. 97.2%) and improved clinical efficacy (arbekacin vs. vancomycin; 90.0% vs. 97.2%) were not different between the two groups. However, the rate of complications was higher in the vancomycin group (33.3%) than in the arbekacin group (5.0%) (<I>P</I>=0.020). In addition, a total of 12 adverse reactions were observed in the vancomycin group; two for hepatotoxicity, one for nephrotoxicity, eight for leukopenia, two for skin rash, and one for drug fever. It is suggested that arbekacin be a good alternative drug to vancomycin in treatment of CSOM caused by MRSA.</P>