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Surface dipole enhanced instantaneous charge pair generation in triboelectric nanogenerator
Kim, Kyeong Nam,Jung, Yun Kyung,Chun, Jinsung,Ye, Byeong Uk,Gu, Minsu,Seo, Eunyong,Kim, Seongsu,Kim, Sang-Woo,Kim, Byeong-Su,Baik, Jeong Min Elsevier 2016 Nano energy Vol.26 No.-
<P><B>Abstract</B></P> <P>Developing a successful strategy to maximize the surface charge density is crucial to speed-up the commercialization success of triboelectric nanogenerator. Here, for the first time, the fabrication of positive triboelectric material to donate electrons efficiently to dielectrics is reported, by increasing the stretchability for the uniform contact and by introducing a functional group for the surface potential control. A highly stretchable and conductive film with Ag nanowires and PDMS was fabricated as a base material, in which the portion of nanowires exposed above the embedding surface should be accurately controlled. In specific, positively charged 4-(dimethylamino)pyridine (DMAP) coated Au nanoparticles, prepared by phase transfer method, are coated. The DMAP lowers the effective work function of the nanoparticles by a permanent dipole induced at the DMAP-Au interface and enhances the electron transfer to the dielectrics, confirmed by the Kelvin probe force microscope measurement. The designed nanogenerator gives an output performance up to 80V and 86μA, and 2.5mW in output power, 2.5 times enhancement compared with the conventional TENG. With the integration with AC to DC converting circuit and buck-boost circuit, the nanogenerator produces a constant voltage of 2.6V. The wireless sensing system, which operates the remote controller, were also demonstrated, turning on a siren.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A positive triboelectric material to donate electrons efficiently to dielectrics is developed. </LI> <LI> The keynote is to increase the stretchability and to introduce a functional group. </LI> <LI> It was proven to be effective for the uniform contact and surface potential control. </LI> <LI> The TENG gave an output performance up to 80 V and 86 μA, and 2.5 mW in output power. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kim Bitbyeol,Kim Ho Kyung,Kim Jinsung,Ki Yongkan,Joo Ji Hyeon,전호상,Park Dahl,Kim Wontaek,Nam Jiho,Kim Dong Hyeon 대한영상의학회 2021 대한영상의학회지 Vol.82 No.6
Purpose Dedicated breast CT is an emerging volumetric X-ray imaging modality for diagnosis that does not require any painful breast compression. To improve the detection rate of weakly enhanced lesions, an adaptive image rescaling (AIR) technique was proposed. Materials and Methods Two disks containing five identical holes and five holes of different diameters were scanned using 60/100 kVp to obtain single-energy CT (SECT), dual-energy CT (DECT), and AIR images. A piece of pork was also scanned as a subclinical trial. The image quality was evaluated using image contrast and contrast-to-noise ratio (CNR). The difference of imaging performances was confirmed using student’s t test. Results Total mean image contrast of AIR (0.70) reached 74.5% of that of DECT (0.94) and was higher than that of SECT (0.22) by 318.2%. Total mean CNR of AIR (5.08) was 35.5% of that of SECT (14.30) and was higher than that of DECT (2.28) by 222.8%. A similar trend was observed in the subclinical study. Conclusion The results demonstrated superior image contrast of AIR over SECT, and its higher overall image quality compared to DECT with half the exposure. Therefore, AIR seems to have the potential to improve the detectability of lesions with dedicated breast CT.