Home About us Contact
|
Home About us Contact | ||
|
|
||
Topography Images (topography + image)
Selected AbstractsMagnetic force microscopy of iron oxide nanoparticles and their cellular uptakeBIOTECHNOLOGY PROGRESS, Issue 4 2009Yu Zhang Abstract Magnetic force microscopy has the capability to detect magnetic domains from a close distance, which can provide the magnetic force gradient image of the scanned samples and also simultaneously obtain atomic force microscope (AFM) topography image as well as AFM phase image. In this work, we demonstrate the use of magnetic force microscopy together with AFM topography and phase imaging for the characterization of magnetic iron oxide nanoparticles and their cellular uptake behavior with the MCF7 carcinoma breast epithelial cells. This method can provide useful information such as the magnetic responses of nanoparticles, nanoparticle spatial localization, cell morphology, and cell surface domains at the same time for better understanding magnetic nanoparticle-cell interaction. It would help to design magnetic-related new imaging, diagnostic and therapeutic methods. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Low-temperature scanning system for near- and far-field optical investigationsJOURNAL OF MICROSCOPY, Issue 3 2003D. V. Kazantsev Summary A combined system for far- and near-field optical spectroscopy consisting of a compact scanning near-field optical microscope and a dedicated spectrometer was realized. The set-up allows the optical investigation of samples at temperatures from 10 to 300 K. The sample positioning range is as large as 5 × 5 × 5 mm3 and the spatial resolution is in the range of 1.5 µm in the far-field optical microscopy mode at low temperatures. In the scanning near-field optical microscope mode the resolution is defined by the microfabricated cantilever probe, which is placed in the focus of a double-mirror objective. The tip-to-sample distance in the scanning near-field optical microscope is controlled by a beam deflection system in dynamic scanning force microscopy mode. After a description of the apparatus, scanning force topography images of self-assembled InAs quantum dots on a GaAs substrate with a density of less than one dot per square micrometre are shown, followed by the first spectroscopic investigations of such a sample. The presented results demonstrate the potential of the system. [source] Structural defects in homoepitaxial diamond layers grown on off-axis Ib HPHT substratesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 12 2006T. Bauer Abstract In the present study homoepitaxial diamond films have been grown by microwave plasma chemical vapour deposition (MWPCVD) on (001)-oriented Ib HPHT substrates with off-axis angles of up to 11°. Freestanding films of several hundred microns thickness were produced by removal of the Ib substrate and of the polycrystalline rim. In high resolution X-ray diffraction (HRXRD) rocking curve measurements the crystals showed a full width at half maximum (FWHM) between (2 × 10,3)°, which is close to the instrumental limit of our setup, and maximum values of (3 × 10,2)°. The structural quality is directly reflected in the strength of the birefringence observed in the optical microscope. While the high quality sample showed a weak birefringence with a couple of localized centres distributed over the whole sample surface, a tatami-like pattern is measured for the sample with the broad rocking curve. Identical defect structures with perfect correspondence are observed in X-ray topography images. Furthermore the X-ray topographs allow to identify isolated dislocation lines. Both characterisation methods show that the defect lines are aligned along the off-axis direction which allows conclusions on the mechanism of formation. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Optical super-resolution using higher harmonics and different acquisition modes in an aperture tapping SNOMPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2010Giovanni Longo Abstract Scanning near field optical microscopy (SNOM) is a well-established technique to obtain a sub-wavelength resolution optical characterization, together with nanometer-scale topography images, on any kind of biological or non-biological sample. Recently we have modified a classical SNOM unit to work in the tapping modality, ensuring stability, versatility and good optical resolution and signal to noise ratio. Exploiting the vertical tip movement, in particular, we were able to access two different optical detection modes: light modulation, which can be obtained by a mechanical chopper or by electronically switching the laser on and off; gap modulation in which the tip's vertical oscillation is used to produce, itself, a modulation of the collected light. Several biological and non-biological samples have been investigated and the data reveal that, despite the signal collected in gap-modulation is at least one order of magnitude smaller than in laser-modulation, resolution, and signal-to-noise ratio in the gap-modulated images is preferable. On the other hand, the higher intensity of the laser-modulation signal allows to deconvolve the optical information at higher harmonics of the tip oscillation frequency. This is a well-known procedure used in the apertureless-SNOM setup to enhance the near-field contribution of the scattered light and reduce the noise content. The interesting results obtained in this Aperture setup are described and commented. [source] | ||||||||||