We present modeling results for the propagation of strong shock waves in metals. In particular, we use an arbitrary Lagrange Eulerian (ALE3D) code to model the propagation of strong pressure waves (P {approx} 300 to 400 kbars) generated with high explosives in contact with aluminum cylinders. The aluminum cylinders are assumed to be both flat-topped and have large-amplitude curved surfaces. We use 3D Lagrange mechanics. For the aluminum we use a rate-independent Steinberg-Guinan model, where the yield strength and shear modulus depend on pressure, density and temperature. The calculation of the melt temperature is based on the Lindermann law. At melt the yield strength and shear modulus is set to zero. The pressure is represented as a seven-term polynomial as a function of density. For the HMX-based high explosive, we use a JWL, with a program burn model that give the correct detonation velocity and C-J pressure (P {approx} 390 kbars). For the case of the large-amplitude curved surface, we discuss the evolving shock structure in terms of the early shock propagation experiments by Sakharov.

The authors present a measurement of the systemic proper motion of the Large Magellanic Cloud (LMC) from astrometry with the High Resolution Camera (HRC) of the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST). They observed LMC fields centered on 21 background QSOs that were discovered from their optical variability in the MACHO database. The QSOs are distributed homogeneously behind the central few degrees of the LMC. With 2 epochs of HRC data and a {approx} 2 year baseline they determine the proper motion of the LMC to better than 5% accuracy: {mu}{sub W} = -2.03 {+-} 0.08 mas yr{sup -1}, {mu}{sub N} = 0.44 {+-} 0.05 mas yr{sup -1}. This is the most accurate proper motion measurement for any Milky Way satellite thus far. When combined with HI data from the Magellanic Stream this should provide new constraints on both the mass distribution of the Galactic Halo and models of the Stream.

Coherent X-ray diffraction microscopy is a method of imaging non-periodic isolated objects at resolutions only limited, in principle, by the largest scattering angles recorded. We demonstrate X-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the 3D diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a non-periodic object. We also construct 2D images of thick objects with infinite depth of focus (without loss of transverse spatial resolution). These methods can be used to image biological and materials science samples at high resolution using X-ray undulator radiation, and establishes the techniques to be used in atomic-resolution ultrafast imaging at X-ray free-electron laser sources.

Detection of breast cancer in fresh tissue obtained from surgery is investigated using Near-infrared autofluorescence imaging under laser excitation at 532-nm and 632.8-nm. The differences in intensity between the three main components of breast tissue (cancer, fibrous and adipose) are estimated and compared to those obtained from cross-polarized light scattering images recorded under polarized illumination at 700-nm. The optical spectroscopic images for each tissue sample were subsequently compared with the histopathology slides. The experimental results indicate that the intensity of the near-infrared emission is considerably different in breast cancer compared to that of the adjacent non-neoplastic tissues (adipose and fibrous tissue). The experimental results suggest that 632.8-nm excitation offers key advantages compared to 532-nm excitation.

The Sn-rich side of the Sn-In phase diagram has been investigated at temperatures ranging from 77 to 500 K by using X-ray diffraction, thermal analysis, and magnetization measurements. It is confirmed that the {beta}-Sn(In)-phase can remain as a metastable phase down to 77 K within the composition range of 86.3-94 at% of Sn. An isothermal displacive (martensitic) transition of the {gamma} phase to the metastable {beta} phase is suggested as the mechanism of the transformation.

The main noise source in detection of faint companions such as extrasolar planets near bright stars with AO is speckle noise - residual PSF structure caused by wavefront errors due to the atmosphere, the AO system, and static optical effects. Of these, the most fundamental are atmospheric speckles - even given infinite wavefront SNR and a perfect DM, timelag between sensing and correction will always lead to a residual atmospheric speckle pattern. There have been several suggestions as to the lifetime of these atmospheric speckles, none strongly supported by theory or simulation. We have carried out a systematic series of simulations and analysis to explore this question. We show that speckles have different behavior in the regime in which diffraction is significant (first-order speckles, which are rapidly modulated as a phase error translates across the aperture) and in the coronagraphic regime (second-order speckles, which evolve only as the phase screen completely clears the aperture). We use simulations to analyze the behavior of speckles in a variety of regimes, showing that the second-order atmospheric speckle lifetime is almost constant irrespective of the properties of the AO system, and is set primarily by the atmospheric clearing time of the telescope aperture.