A fast technique for recursive scene matching using pyramids

An algorithm of a fast correlation technique for scene matching using pyramidal image representation is introduced. A mathematical model of the image registration process based on the pyramidal representation of a separable Markov random field is considered in order to evaluate threshold sequence for the algorithm. Experimental results are presented for matching images, both free of noise and corrupted by noise. Theoretical and experimental results given in the paper show that computational efficiency in scene matching could be improved in three orders of magnitude comparatively to the traditional correlation technique.     

Optical depth measurements by shadow-band radiometers and their uncertainties

Shadow-band radiometers in general, and especially the Multi-Filter Rotating Shadow-band Radiometer (MFRSR), are widely used for atmospheric optical depth measurements. The major programs running MFRSR networks in the United States include the Department of Energy Atmospheric Radiation Measurement (ARM) Program, U.S. Department of Agriculture UV-B Monitoring and Research Program, National Oceanic and Atmospheric Administration Surface Radiation (SURFRAD) Network, and NASA Solar Irradiance Research Network (SIRN). We discuss a number of technical issues specific to shadow-band radiometers and their impact on the optical depth measurements. These problems include instrument tilt and misalignment, as well as some data processing artifacts. Techniques for data evaluation and automatic detection of some of these problems are described.     

Chemical vapor deposition of Ni-C films from bis-(ethylcyclopentadienyl) nickel

Metal-organic chemical vapor deposition (MOCVD) is widely used for deposition of various nickel-containing coatings, such as catalytic nickel thin films and nanoparticles, nickel silicide alloys and magnetic carbon-nickel nanocomposite layers. Here we report preliminary results from an attempt to use bis-(ethylcyclopentadienyl) nickel [(EtCp)2Ni] as a precursor for MOCVD of Ni-C thin films in the (EtCp)2Ni-Ar and (EtCp)2Ni-H2-Ar reaction systems. Mechanism of precursor fragmentation was proposed on the basis of the results from a study of gaseous reaction products in the exhaust line of the reactor by means of mass-spectrometry. It was found that an introduction of hydrogen in the gas phase led to an increase in conversion rate of the precursor. Deposited films were analyzed by means of atomic force microscope (AFM), scanning electron microscopy (SEM), X-ray fluorescence spectroscopy (XFS). The effect of hydrogen on growth rate, composition, and morphology of the deposited Ni-C films were experimentally studied.     

Flexible and general synthesis of functionalized phosphoisoprenoids for the study of prenylation in vivo and in vitro

Protein modification with isoprenoid lipids affects hundreds of signaling proteins in eukaryotic cells. Modification of isoprenoids with reporter groups is the main approach for the creation of probes for the analysis of protein prenylation in vitro and in vivo. Here, we describe a new strategy for the synthesis of functionalized phosphoisoprenoids that uses an aminederivatized isoprenoid scaffold as a starting point for the synthesis of functionalized phosphoisoprenoid libraries. This overcomes a long-standing problem in the field, where multistep synthesis had to be carried out for each individual isoprenoid analogue. The described approach enabled us to synthesize a range of new compounds, including two novel fluorescent isoprenoids that previously could not be generated by conventional means. The fluorescent probes that were developed using the described approach possess significant spectroscopic advantages to all previously generated fluorescent isoprenoid analogue. Using these analogues for flow cytometry and cell imaging, we analyzed the uptake of isoprenoids by mammalian cells and zebrafish embryos. Furthermore, we demonstrate that derivatization of the scaffold can be coupled in a one-pot reaction to enzymatic incorporation of the resulting isoprenoid group into proteins. This enables rapid evaluation of functional groups for compatibility with individual prenyltransferases and identification of the prenyltransferase specific substrates.     

Precipitation –a baricentrical approach

 Described in this paper are a method and a device for investigating the sedimentation of the disperse phase in liquid polydisperse systems as a function of time and under the influence of the earth’s gravitational pull. A parameter for quantifying suspensions and emulsions according to their ability to form a sediment under the influence of gravity is described. This parameter based on measuring the horizontal component of the displacement of the centre of mass of the liquid system under investigation throughout the course of its precipitation. The system itself is investigated directly in the packaging in which it is stored and sold, which is placed immobilised and at an angle to the vertical line. The packaging remains undamaged throughout the whole investigation. This method is universal as it can be applied to all kinds of liquid polydisperse systems, i.e. fine, rough, opaque, transparent, etc. Received: 24 May 1996     

On the dead-zone formation and limit analysis in axially symmetric extrusion

For axisymmetric direct and indirect extrusion, a kinematically admissible velocity field based on a simple radial flow field combined with the asymptotic behaviour required of a real velocity field near a velocity discontinuity surface is proposed. The influence of the extrusion ratio on the shape of a dead zone and the extrusion pressure is investigated. The result obtained for the upper bound on the extrusion pressure is compared with other solutions. It is shown that using the asymptotic velocity field slightly improves the prediction of the extrusion pressure in comparison with the other solutions based on radial flow. The main advantages of the approach proposed are that it is applicable to a class of processes and that it accounts for the behaviour of a real velocity field in the vicinity of velocity discontinuity surfaces/maximum friction surfaces where various physical effects like local heating, recrystalization, and transformations occur.