Diffraction Fields of Fractally Bounded Apertures

Experimental study is performed of optical diffractions by two-dimensional, self-similar mass and surface fractal apertures as well as mass fractal apertures bounded by surface fractals. Self-similar intensity distributions are observed in the Fraunhofer diffraction fields from surface and mass fractal apertures. Power law decays in average intensities of the diffraction patterns are also investigated for the mass, surface and combined fractal apertures in connection with the fractal dimensions of the objects.     

An effect of curvature of rotating diffuse objects on the dynamics of speckles produced in the diffraction field

The time correlation function is analyzed of the speckel intensity fluctuation produced in the Fresnel diffraction field from a rotating diffuse object under illumination of a Gaussian laser beam. The dependence of the curvature radius of the rotating diffuse object on the time correlation length of the speckle intensity fluctuation is especially explored by taking into account the size of the detecting aperture. The theoretical results are confirmed experimentally for detecting apertures with various sizes. It is shown that a detecting aperture with an appropriate size is required. It becomes useful for determining the radius of curvature of the rotating diffuse object from measurements of the time correlation length of the speckle intensity fluctuation.     

Application of difference NOE-pumping NMR technique and cold-spray ionization mass spectrometry to identify a ligand binding with a protein receptor.

A difference diffusion-based NMR technique and cold-spray ionization mass spectrometry were employed as a solution-based approach for identifying a ligand binding with a protein receptor. The difference diffusion-based NMR technique, called difference NOE-pumping, can directly detect the ligand interacting with a protein receptor. This technique uses a simple pulse sequence and the diffusion filter can easily be optimized. The cold-spray ionization mass spectrometry (CSI-MS), a variant of electrospray ionization mass spectrometry (ESI-MS) operating at low temperature, has been applied to detect the ligand-receptor complex. The efficiency of these techniques for identifying binding ligands is demonstrated with the human serum albumin (HSA)-drug system.     

Fragmentation of tertiary cyclopropanol compounds catalyzed by vanadyl acetylacetonate

Tertiary cyclopropanol compounds react with a catalytic amount of vanadyl acetylacetonate in the presence of oxygen affording β-hydroxyketones and β-diketones. For 3-substituted-bicyclo[4.1.0]alkanols, peroxides are obtained, as are the β-hydroxyketones. Conversely, 2-ethoxycarbonylcyclopropyl silyl ethers produce ethyl γ-oxocarboxylate derivatives given the same reaction conditions.     

Diffraction patterns of off-axis gaussian beams in the presence of third-order spherical aberration in the optical system

The intensity distribution of diffraction patterns for off-axis gaussian beams at the image plane of an optical system with third-order spherical aberration is calculated by using the concept of the beam aberration function previously introduced by the present authors. The results show how the peak intensity of the diffraction patterns diminishes and how the transversel focal shift occurs as a function of the incident position of the beams at the pupil plane and their beam size.     

Die protonchemischen Verschiebungen und die stereochemischen Strukturen von Polyvinylchlorid

Ohne Zusammenfassung     

Conformational transitions of poly(β-benzyl L-aspartate)

Conditions that affect the conformation of poly(β-benzyl L-aspartate) in films have been studied. A slow transition from the left-handed to the right-handed α-helical form is observed under certain conditions in half-dried film cast from chloroform solutions and after exposure of amorphous films of the left-handed β-helical form to chloroform vapor. This transition is caused by adsorption of moisture. Thermal transitions of these films were examined by differential scanning calorimetry and infrared spectroscopy. The right-handed α-helices change to left-handed ω-helices around 140°C, and sharp exothermic peak is observed in this region for some films.     

Bicyclo[3.3.0]octenol as an effective tool for the determination of absolute configuration of chiral acids. The absolute configuration of aryl-t-butylacetic acid

(+)-endo-cis-Bicyclo[3.3.0]oct-7-en-2-ol gave good optical yields in the kinetic resolution of aryl-t-butylacetic anhydrice, establishing the absolute configuration of t-butyl-α-naphthylacetic acid as (S) - (+).     

Simple computer-generated holograms displayed by an x-y plotter

New simple computer-generated holograms displayed by an x-y plotter are proposed and investigated. In the construction of holograms by computer, phase coding methods are used in order to distribute the Fourier-transform values of an original object over the whole of the receiving plane where the hologram is to be constructed. It is found that relatively good images are reconstructed from the computer-generated holograms proposed here.     

Granularity growth of laser speckle and its application to surface inspection

A process of granularity growth in partially developed speckle patterns produced in the near field of wavy object surfaces illuminated using a laser has been experimentally studied by investigating the probability density function and average contrast of their intensity variations. These parameters have been measured as a function of the distance from the object surface to the detector for four typical sample objects having different surface qualities. It has been found that the variation in average speckle contrast with receiving distance is strongly dependent on the surface quality of the objects. The saturated value of the speckle contrast, found from the graph of its dependence on receiving distance, is also related to the maximum height of irregularities in the surface.