Search Results

You are looking at 1 - 10 of 975 items :

  • "dark-field" x
Clear All

measure their full width at half-maximum (FWHM) of the LSPR-modulated photoluminescence (PL) from the materials [ 21 ], [ 22 ], [ 23 ] or the dark-field (DF) scattering spectra [ 15 ], [ 24 ], [ 25 ], [ 26 ], [ 27 ]. Although the PL method usually has a higher signal to noise ratio, due to its easily eliminated excitation background. It has several limitations. First, it only works for metals with a broad and featureless luminescence spectrum, like Au. The spectral range that this method can apply is restricted by the metal itself. Even for Au, it becomes impractical in

American Mineralogist, Volume 80, pages 1174-1178, 1995 High-angle annular dark-field microscopy of franckeite Su W,lNcr* P. R. Busncr Departments of Geology and Chemistry/Biochemistry, Arizona State University, Tempe, Arizona 85287, U.S.A. J. Lru** Center for Solid State Science, Arizona State University, Tempe, Arizona 85287, U.S.A. AssrRAcr Franckeite (-FeSnrPbrSbrS,o) is a sulfosalt mineral with a modulated structure. Its complex composition and composite layered structure, lack of a well-defined unit cell, incommensurate character, and poor crystal quality

1064 DARK-FIELD ELECTRON MICROSCOPY OF AMORPHOUS SEMICONDUCTORS M. L. Rudee Rice University- Houston , Texas ABSTRACT Dark-field electron microscopy has "been used to investigate the structure of amorphous Ge and Si films. Ordered domains of about 15À and 20Ì diameter have been observed in Ge and Si, respectively. Some evidence suggests that nearly all of the material in the film exists within the ordered domains. During annealing, areas of both amorphous and macroscopical- ly polycrystalline Ge exist simultaneously. Since these films have been shown


X-ray phase and dark-field contrast have recently been the source of much attention in the field of X-ray imaging, as they both contribute new imaging signals based on physical principles that differ from conventional X-ray imaging. With a so-called Talbot grating interferometer, both phase-contrast and dark-field images are obtained simultaneously with the conventional attenuation-based X-ray image, providing three complementary image modalities that are intrinsically registered. Whereas the physical contrast mechanisms behind attenuation and phase contrast are well understood, a formalism to describe the dark-field signal is still in progress. In this article, we report on correlative experimental results obtained with a grating interferometer and with small-angle X-ray scattering. Furthermore, we use a proposed model to quantitatively describe the results, which could be of great importance for future clinical and biomedical applications of grating-based X-ray imaging.

American Mineralogist, Volume 100, pages 2749–2752, 2015 0003-004X/15/1112–2749$05.00/DOI: 2749 *E-mail: Letter Dislocation microstructures in simple-shear-deformed wadsleyite at transition-zone conditions: Weak-beam dark-field TEM characterization of dislocations on the (010) plane Nobuyoshi MiyajiMa1,* aNd takaaki kawazoe1 1Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany abstract Dislocation microstructures of an (010)[001]-textured wadsleyite have been

particle resonant wavelength, D is the diameter of the particles and τ is the decay constant. To prove the versatility of our approach, dimers of increasingly coupled nano-spheres with gap widths between 35 nm and 5 nm are fabricated and examined by dark-field spectroscopy. The measured spectra are analyzed using the aforementioned scaling law. 2 Experimental section For the fabrication of nano-pillars, silicon substrates with native oxide were cleaned by ultrasonication in acetone and isopropanol (IPA). After drying with nitrogen they were spin-coated with three


The flow-inducing effect of the bobbin-tool features (tri-flat pin and scrolled shoulder) were replicated by a simple analogue model for aluminium welds by layered plasticine samples. Flow patterns of the weld zone were clarified by a typical stereomicroscopy instrument assisted by dark-field/bright-field illumination. The effects of the pin features, specifically threads and flats in centre of bond zone and scrolled shoulder in sides of stirred zone, were identified. This study shows that internal flow features for BFSW welds is transferable from the friction stir welding process to the functional metal forming processes such where the shearing can extensively affect the microstructure. The similarity between the flow pattern of the provided aluminium samples and the plasticine analogue can validate the accuracy of the flow model presented in this work.

grain containing dispersed hematite microcrystals from room temperature up to 800 °C using an in situ, high-temperature visible micro-spectrometer with dark field optics. The spectrum of room-temperature hematite powder is characterized by a nearly constant reflectivity in the range 400–550 nm, a shoulder near 620 nm, and a reflectivity maximum near 750 nm. The reflectance spec- trum is similar to the diffuse reflectance spectra measured by a spectrophotometer and a conventional spectrometer with an integrating sphere. This result indicates that the dark field

-field (BF) mode were obtained using a Philips CM200 TEM equipped with a LaB 6 source, double-tilt holder and Gatan digital camera, operated at 200 kV. The illumination area for electron diffractions is 200 nm. Measurements on the diffractions and image analysis were performed using DigitalMicrograph 1.83.842. Electron diffractions were indexed using WinWulff 1.5.2 and data from the American Mineralogist Crystal Structure Database ( . High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging

to selectively image isolated dimer antennas in the confocal dark-field microscope. In the first two, gallium-based lithography strategies, the Ga + -ion beam (blue) with a current of 24 pA, was used to remove most of the gold film (A), followed by a second step of Ga + -ion beam writing at a current of 7.7 pA to outline the still-connected dimer nanorods (B). The dimers were finalized in a third step by cutting through the nanorods using either the Ga-FIB (“gallium lithography”) or the He-FIB (“gallium/helium lithography”) at a current of a few pA (C). Figure 1D