Orthogonal hexatic smectic phase-rare or common?

The hexatic smectic B (Hex B) phase is commonly encountered among hydrogen-bonded liquid crystal materials. Among enaminoketone and Schiff's base compounds, twenty homologous series (c. 10² compounds) exhibiting orthogonal mono-or bi-layer hexatic phases were identified by combined microscopy and DSC. Phase transitions from crystal B (CrB) of S_f to Hex B as well as from Hex B to S_f, S_a or S_c phases were observed within the range 50 to 190°C. Temperature ranges of the Hex B phase detectable by DSC varied from 0.2 to 20°C. Within two groups of three-ring enaminoketones, the formation of the Hex B phase was found to be controlled by both inductive and mesomeric components of the Hammett constants of the terminal substituents of the molecules.     

On the Glivenko-Cantelli problem in stochastic programming: Mixed-integer linear recourse

Expected recourse functions in linear two-stage stochastic programs with mixed-integer second stage are approximated by estimating the underlying probability distribution via empirical measures. Under mild conditions, almost sure uniform convergence of the empirical means to the original expected recourse function is established.     

Effect of a characteristic length on crack spacing in a reinforced concrete bar under tension

The paper presents quasi-static FE-simulations of the crack formation in a reinforced concrete bar without stirrups subject to tension. The material was modeled with a continuum smeared crack model using an elasto-plastic constitutive law. A linear Rankine criterion with isotropic softening and associated flow rule was adopted in a tensile regime. To ensure the mesh-independency, the softening parameter was enhanced by a characteristic length of micro-structure by means of a non-local theory. Attention was laid to the effect of a different characteristic length of micro-structure and initial bond-slip stiffness on the spacing of localized zones.     

MR microscopy of water diffusion tensor in biological systems

Diffusion tensor imaging (DTI) of the control and mechanically injured spinal cord of a ratin vitro andin vivo are reported.In vitro experiments were done on a home-built 6.4 T magnetic resonance microscope. Results for formaline-fixed samples show significant differences in diffusion tensor components between gray matter and white matter of the control spinal cord. Moreover, it is shown that already 6–10 min after the injury DTI can detect changes in water diffusion in areas extending far beyond the region of primary tissue damage.In vivo experiments were performed using a 9.4 T Magnex magnet and Bruker Medspec imaging system. Good-quality DTI images, free from motion artifacts were obtained. Results from control samples confirm differences in water diffusion between white matter and gray matter, observedin vitro. In vivo experiments show that characteristic changes in water diffusion observedin vitro 6–10 min after injury are preserved 60–360 min after injury, without significant alteration during this time.     

On the Uniqueness of the Density for the Invariant Measure in an Infinite Hyperbolic Iterated Function System

Periodica Mathematica Hungarica - We consider a regular infinite hyperbolic iterated function satisfying a property which guarantees that the associated Frobenius-Perron operator ? is almost...     

Accurate determination of individual lanthanides in biological materials by NAA with pre-and post-irradiation separation

An intelligent hydrogel with both pH and temperature sensitivity was obtained by grafting acrylic acid and dimethylaminoethylmethacrylate onto preirradiated polypropylene (PP) film by two-step reactions. The effect of first and second reactions on the degree of grafting was studied. The grafted sample films were checked by Fourier transform infrared spectrophotometry in the attenuated total reflectance mode. The morphology of the PP samples was observed by scanning electron microscope in different conditions before and after grafting, respectively.