Apr. 19, 2012

Shear Localization in Gamma-Based Titanium Aluminides

Hot-working of intermetallic γ titanium aluminides is often hampered by their liability to shear localization and subsequent crack formation, thereby preventing a refinement of the microstructure by dynamic recrystallization. The mechanisms leading to shear localization and cracking were microstructurally analyzed using scanning (SEM) and transmission (TEM) electron microscopic techniques.
moreApr. 10, 2012

Quantitative Phase Microscopy

Classical phase contrast microscopy techniques allow only non-quantitative partial visualization of transparent samples. In recent years, a variety of techniques have appeared for complete phase determination with different levels of complexity. A new simple non-interferometric method able to provide real time quantitative optical path difference information is presented. It is based on the use of a refractive pyramid to measure the transillumination wavefront gradient using incoherent light.

Introduction
moreMar. 29, 2012

Analyzing Biomaterials by Nanofocus Computed Tomography

3D biomaterials are known to function as alternative bone grafts. In the area of Tissue Engineering (TE) 3D matrices are often used in combination with mesenchymal stem cells to build up a functional tissue graft. In this approach the selection of a matrix is a crucial factor. For bone TE applications the matrix should fulfill the following geometrical properties. moreMar. 20, 2012

Coherence Probe Microscopy - Contrast Modification and Image Enhancement

Coherence probe microscopy represents a contemporary method for non-destructive investigation of micro-materials providing depth resolved information about the sub-surface domain. We present that Fourier plane filtering can be integrated in such a low-coherence interferometric imaging system and demonstrate how image contrast can be modified and enhanced, similar to microscopy but now additionally in a depth-resolved way. Thereby we focus on weakly scattering technical multi-layer structures.
moreMar. 13, 2012

Fascinating Silk - Electrospinning, Contraction and Diffraction Experiments

Silk from spider and silkworm shows exceptional mechanical strength, toughness and extensibility if compared to man-made fibers. Other amazing properties are the occurrence of reversible cyclic contraction as well as of permanent super-contraction in fibroin nanofibers electrospun from regenerated Bombyx mori silk. We discovered the key role of the metastable silk-I modification and of the non-crystalline regions with oriented chains in the cyclic behavior under restrained conditions, and the role the silk-II ß-crystallinity plays in super-contraction.
moreMar. 02, 2012

Exploring the Concert of Neuronal Activities

How do real neural networks, composed of numerous different types of neurons, interconnected by complex arrangements of synapses, process information? Randy M. Bruno, Ph.D., Assistant Professor at the Department of Neuroscience, Columbia University, NY, USA is pursuing this question using the rodent whisker-barrel system. Here, anatomically and functionally distinct networks - barrels and barrel columns - are clearly identifiable, and the sensory transducers that provide input are directly controllable. moreFeb. 28, 2012

Nanosized Films of Fe2O3

We have investigated nanosized thin films of α-Fe2O3 (hematite) with addition of Lithium, by the impedance spectroscopy (IS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). moreFeb. 13, 2012

Full-Field MicroXRF Imaging

To obtain volumetric information on the chemical composition inside objects, a full-field micro X-ray fluorescence (microXRF) imaging technique has been implemented. Opposed to the traditional point-by-point methods using confocal imaging, this new method collects complete 2D XRF projections of 3D objects without any scanning. And in contrast with EDX surface mapping in an SEM, having complete information from the entire volume allows creating 3D XRF images non-destructively by tomographic reconstruction. more