Constituent elements and their distribution in the radioactive Cs-bearing silicate glass microparticles released from Fukushima nuclear plant.

Microparticles of radioactive cesium (Cs)-bearing silicate glass emitted from the Fukushima Daiichi nuclear power plant were investigated mainly using state-of-the-art energy-dispersive X-ray spectroscopy in scanning transmission electron microscopes. Precise elemental maps of the particles were obtained using double silicon drift detectors with a large collection angle of X-rays, and qualitative elemental analysis was performed using high-resolution X-ray spectroscopy with a microcalorimetry detector. Beside the substantial elements (O, Si, Cl, K, Fe, Zn, Rb, Sn and Cs) as previously reported, Mn and Ba were also common, though their amounts were small.

Internal structure of cesium-bearing radioactive microparticles released from Fukushima nuclear power plant.

Microparticles containing substantial amounts of radiocesium collected from the ground in Fukushima were investigated mainly by transmission electron microscopy (TEM) and X-ray microanalysis with scanning TEM (STEM). Particles of around 2 μm in diameter are basically silicate glass containing Fe and Zn as transition metals, Cs, Rb and K as alkali ions, and Sn as substantial elements. These elements are homogeneously distributed in the glass except Cs which has a concentration gradient, increasing from center to surface.

Large, negative magnetoresistance in an oleic acid-coated Fe(3)O(4) nanocrystal self-assembled film.

An oleic acid-coated Fe3O4 nanocrystal self-assembled film was fabricated via drop casting of colloidal particles on a SiO2/Si substrate. The film exhibited bifurcation of the zero-field-cooled and field-cooled magnetizations around 250 K. The nonlinear current-voltage (I-V) characteristics between the source and drain electrodes in both zero and non-zero magnetic fields (H) were observed above and below the bifurcation temperature.

Atomic imaging and spectroscopy of low-dimensional materials with interrupted periodicities.

Identification of individual atoms and examination of their electronic properties in materials are the ultimate goal of all microscopy-based analytical techniques. Here, we demonstrate successful single-atom imaging and spectroscopy in low-dimensional materials using (scanning) transmission electron microscopy together with electron energy-loss spectroscopy (EELS). Edges and point defects in single-layered materials such as graphene, hexagonal boron nitride and WS(2) nanoribbons are investigated by annular dark-field imaging and EELS fine-structure analysis.

Remote catalyzation for direct formation of graphene layers on oxides.

Direct deposition of high-quality graphene layers on insulating substrates such as SiO(2) paves the way toward the development of graphene-based high-speed electronics. Here, we describe a novel growth technique that enables the direct deposition of graphene layers on SiO(2) with crystalline quality potentially comparable to graphene grown on Cu foils using chemical vapor deposition (CVD). Rather than using Cu foils as substrates, our approach uses them to provide subliming Cu atoms in the CVD process.