• Title/Summary/Keyword: FePt nanoparticles

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Application of Image Processing to Determine Size Distribution of Magnetic Nanoparticles

  • Phromsuwan, U.;Sirisathitkul, C.;Sirisathitkul, Y.;Uyyanonvara, B.;Muneesawang, P.
    • Journal of Magnetics
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    • v.18 no.3
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    • pp.311-316
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    • 2013

  • Digital image processing has increasingly been implemented in nanostructural analysis and would be an ideal tool to characterize the morphology and position of self-assembled magnetic nanoparticles for high density recording. In this work, magnetic nanoparticles were synthesized by the modified polyol process using $Fe(acac)_3$ and $Pt(acac)_2$ as starting materials. Transmission electron microscope (TEM) images of as-synthesized products were inspected using an image processing procedure. Grayscale images ($800{\times}800$ pixels, 72 dot per inch) were converted to binary images by using Otsu's thresholding. Each particle was then detected by using the closing algorithm with disk structuring elements of 2 pixels, the Canny edge detection, and edge linking algorithm. Their centroid, diameter and area were subsequently evaluated. The degree of polydispersity of magnetic nanoparticles can then be compared using the size distribution from this image processing procedure.

  • https://doi.org/10.4283/JMAG.2013.18.3.311 인용 PDF KSCI

Pt/MOF-5 Hybrid Composite Encapsulated with Microporous Carbon Black to Improve Hydrogen Storage Capacity and Hydrostability

  • Yeo, Sin-Yeong;Gwak, Seung-Yeop
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.45.2-45.2
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    • 2011

  • Metal organic frameworks (MOF) have generated considerable interests as a potential candidate for hydrogen storage owing to their extremely high surface-to-volume ratio and low density. In this study, Pt nanoparticles of about 3 nm in size were introduced outside MOF-5 [$Zn_4O$(1,4-benzenedicarbocylate)3], which was then encapsulated with hydrophobic microporous carbon black (denoted CB@Pt/MOF-5) in order to enhance hydrogen uptake capacity without decreasing the specific surface area and hydrostability. To study the chemical composition, morphology, crystal information, and properties of the synthesized material, a variety of techniques is employed, including WXRD, XPS, ICP-AES, FE-SEM, HR-TEM, and N2 adsorption-desorption, confirming the formation of novel hybrid composite designated CB@Pt/MOF-5 with highly crystalline structure, large specific surface area and pore volume. In addition, $H_2$ storage capacity for resulting material was measured using magnetic suspension microbalance at 77 and 298 K under high-pressure condition, and the hydrostability was also tested by exposing the sample to 33% relative humidity at $23^{\circ}C$ and measuring XRD as a function of time.

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Gas sensing properties of polyacrylonitrile/metal oxide nanofibrous mat prepared by electrospinning

  • Lee, Deuk-Yong;Cho, Jung-Eun;Kim, Ye-Na;Oh, Young-Jei
    • Journal of Sensor Science and Technology
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    • v.17 no.4
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    • pp.281-288
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    • 2008

  • Polyacrylonitrile(PAN)/metal oxide(MO) nanocomposite mats with a thickness of 0.12 mm were electrospun by adding 0 to 10 wt% of MO nanoparticles ($Fe_2O_3$, ZnO, $SnO_2$, $Sb_2O_3-SnO_2$) into PAN. Pt electrode was patterned on $Al_2O_3$ substrate by DC sputtering and then the PAN(/MO) mats on the Pt patterned $Al_2O_3$ were electrically wired to investigate the $CO_2$ gas sensing properties. As the MO content rose, the fiber diameter decreased due to the presence of lumps caused by the presence of MOs in the fiber. The PAN/2% ZnO mat revealed a faster response time of 93 s and a relatively short recovery of 54 s with a ${\Delta}R$ of 0.031 M${\Omega}$ at a $CO_2$ concentration of 200 ppm. The difference in sensitivity was not observed significantly for the PAN/MO fiber mats in the $CO_2$ concentration range of 100 to 500 ppm. It can be concluded that an appropriate amount of MO nanoparticles in the PAN backbone leads to improvement of the $CO_2$ gas sensing properties.

  • https://doi.org/10.5369/JSST.2008.17.4.281 인용 PDF KSCI