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In this Letter, the time reversal mirror is used to focus elastic energy at a prescribed location and to analyze the amplitude dependence of the focus signal, thus providing the nonlinearity of the medium. By varying the frequency content of the focused waveforms, the technique can be used to probe the surface, by penetrating to a depth defined by the wavelength of the focused waves. The validity of this concept is shown in the presence of gradual and distributed damage in concrete by comparing actual results with a reference nonlinear measurement and X ray tomography images. [ABSTRACT FROM AUTHOR]

We have performed an analyzer crystal based phase contrast imaging (ABI) experiment using a rotating anode x-ray source. The use of such an incoherent source demonstrates the potential of ABI as a quantitative characterization tool for the laboratory environment. A phase contrast image of a plastic phantom was recorded on high resolution x-ray film and the projected thickness was retrieved from a single image. The projected thickness recovered from the phase contrast image was shown to quantitatively agree with a reference optical microscope measurement. [ABSTRACT FROM AUTHOR]

The effects of x-ray irradiation on the electrical performance of organic thin film transistors (OTFTs) have been examined up to equivalent lifetime doses for medical digital x-ray imaging backplanes. Transistor performance metrics have been assessed before and after exposures up to 500 Gy for bottom-gate, bottom-contact OTFTs of p-channel polytriarylamine and polyfluorene semiconductors. There is no discernible degradation in device performance for either material and no indication of the creation of additional trap states. In situ measurements indicate that x-ray exposure tends to reverse undesirable shifts in the threshold voltage due to prolonged atmospheric exposure and bias stress. [ABSTRACT FROM AUTHOR]

An x-ray streak camera with high resolution in both temporal and spatial dimensions has been developed. It is achieved by using extraction-mesh acceleration and a large opening aperture magnetic solenoid lens design. High resolutions in the temporal and spatial dimensions can be retained in a wide 53 ps time window. A temporal resolution of 233 fs and a spatial resolution of 10 μm have been demonstrated using a Au photocathode. [ABSTRACT FROM AUTHOR]

X-ray photoemission spectroscopy and optical absorption have been used to study the interaction between LiF dopant and various organic semiconductor hosts including N,N′-diphenyl-N,N′-bis (3-methylphenyl)-1, 1′-biphenyl-4, 4′-diamine (TPD), N,N′-bis (1-naphthyl)-N,N′-diphenyl-1, 1′-biphenyl-4, 4′-diamine (NPB), tris (8-hydroxyquinolinato) aluminum (Alq3), C60, and copper phthalacyanine (CuPc). It was found that there is a charge transfer between host and dopant in the Alq3–LiF and C60–LiF systems, while no such charge transfer was observed for the TPD–LiF, NPB–LiF, and CuPc–LiF systems. The experimental data show that F- anion acts as an n-type donor—donating electron charge to the electron transport molecules. [ABSTRACT FROM AUTHOR]

An anodized aluminum oxide nanopore has been used as an x-ray lithography mask to achieve a feature size of ∼35 nm on the polymethylmethacrylate photoresist. The mask was exposed using synchrotron radiation and demonstrates the feasibility of forming large arrays of regular nanostructures. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]