Integrated Digital Image Correlation considering gray level and blur variations: Application to distortion measurements of IR camera

The acquisition of images with different modalities may involve different alterations with respect to an ideal model. Inhomogeneous brightness and contrast, blur due to non-ideal focusing, distortions are common. It is proposed herein to account for such effects for instance by registering a calibration target image with an actual optical image to measure lens distortions. An Integrated Digital Image Correlation (I-DIC) algorithm is proposed to account for the above artifacts and the algorithm is detailed. The resolution and uncertainty of the technique are first investigated on synthetic images, and then applied to the measurement of distortions for infrared (IR) images. The procedure is shown to reduce drastically the residual level assessing the validity of the image formation model, but more importantly allowing for a much improved registration of images.     

The paracrystalline nature of the purple membrane of halobacterium halobium

Summary The paracrystalline fluctuations arising from the imperfect packing of bilayer stacks in dry oriented purple membrane of Halobacterium halobium have been investigated by small-angle X-ray diffraction. The values of the relative inter-membrane macro-lattice distortions and coherently diffracting length along the bilayer stack are respectivelyg = 4,5% andD = 680 Å. The hydratation of the membrane reduces the size of the coherently diffracting domains and increases the relative fluctuation of the membrane stack according to the * law.

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Zusammenfassung Die parakristallinen Fluktuationen, hervorgerufen von gestörten Schichtstrukturen aus getrockneter, orientierter Halobacterium halobium Purple Membran, wurden mittels Röntgenkleinwinkelstreuung untersucht. Die Werte der flüssigkeitsähnlichen Gitterstörungen der Schichtstruktur der Membran und der kohärent streuenden Bereiche entlang der Schichten sind jeweils g = 4,5% und D=680 Å. Die Wasseranreicherung der Membran verkleinert die Größe der kohärent streuenden Bereiche und vergrößert die statistischen Abstandsfluktuationen der Schichtstruktur der Membran nach dem * Gesetz.

     

Crystal Structure of the Dietary Supplement Ferrous Glycine Sulfate

The crystal structure of ferrous glycine sulfate (a ferroglycine sulfate complex with chemical formula FeSO₄(C₂H₅NO₂), a compound extensively used as an iron dietary supplement, was refined from synchrotron X‐ray powder diffraction data. The crystal structure of an (so‐far unreported) isostructural manganese analogue was also structurally detailed by a Rietveld refinement against the corresponding X‐ray powder diffraction pattern. All studied compounds crystallize in the monoclinic P2₁ space group, building layers of metal cations coordinated by the oxygen atoms of sulfate groups and glycine ligands. Neighboring layers are parallel packed, bonded by hydrogen bonds. The coordination polyhedra around the cations can be regarded as distorted and elongated octahedral, presumably due to severe strains present in the crystal structure of the layers.     

New structural features of non-crystalline tetrahedrally bonded networks: A modeling approach

A large model of amorphous silicon (2052 atoms) with 0.5% dangling bonds has been built and investigated. The refinement of the coordinates evidenced the presence of small domains with advanced ordering. These domains preclude the formation of crystallization nuclei and play an essential role in the redistribution of the defects in the material with homogenization of the free energy and stabilization against aging. An effect of amorphization of the ordered nuclei due to free energy redistribution is assessed. The glass relaxation of a-Si (a-Ge) occurring during heating below T_g receives a natural explanation as a structural change from local quasi-ordering to homogeneous disordering.     

On the Relationship Between Microhardness and Crystal Perfection of Chain-Extended Polyethylene

Abstract

The crystal hardness-crystal perfection correlation of polyethylene (PE) samples crystallized at high pressure from the melt (chain extended) has been studied and compared to melt crystallized samples at atmospheric pressure (chain folded). For this purpose the chain extended PE samples were analyzed by WAXS and the paracrystalline lattice distortion parameter values, g ₁₁₀, were calculated. Results are discussed in the light of structural and thermodynamical predictions. Analysis of data confirm the close existing correlation, previously found for chain-folded crystals, between the crystal hardness and g ₁₁₀, including now both the values for chain-folded and chain-extended crystals.     

PET纤维中的次晶结构及晶粒增大的机理

用方差-范围函数的方法分析了一组热处理PET纤维的X光衍射数据,测出了各样品(010)和(100)方向上的晶粒尺寸M、第二类晶格畸变的畸变因子g及晶粒尺寸分散性指数.发现在T~*=503K处,曲线InM～1/T.上出现折点,晶粒尺寸分散性指数出现极大值.据此提出样品中晶粒增大的机理:当T相似文献