Kinetics of BaTiO3 and PbTiO3 Formation from Metallo-organic Precursors

Kinetics of BaTiO₃ and PbTiO₃ formation from metalloorganic precursors were studied. The fine grain size of the decomposed product and the greater degree of mixing led to very rapid kinetics of compound formation. The kinetics data were fitted to the Carter model for a diffusion-controlled process. Formation of PbTiO₃ was modeled as a two-stage process with a single activation energy, and the formation of BaTiO₃ as a single-stage process.     

Effect of spinneret hole diameter on the spinning and properties of acetate fibre

Conclusions The effect of the number and diameter of spinneret holes on hole clogging and the properties of acetate yarns has been investigated under manufacturing conditions.On reducing spinneret hole diameter and increasing the number of holes, the strength and fatigue properties are raised, but the elongation of acetate yarn is reduced.Translated from Khimicheskie Volokna, No. 1, pp. 29–30, January–February, 1986.     

Associative properties of perfluorooctyl end‐functionalized polystyrene–poly(ethylene oxide) diblock copolymers

The synthesis of 2,2,3,3‐tetrahydro‐perfluoroundecanoyl end‐functionalized polystyrene–poly(ethylene oxide) block (PS‐block‐PEO‐R_F) copolymers and their matching PS‐block‐PEO diblock copolymers was carried out by sequential anionic polymerization. Viscometry and ¹⁹F NMR studies show that the PS‐block‐PEO copolymers, in contrast to their matching PS‐block‐PEO‐R_F copolymers, exhibit a micellar rather than the associative behavior seen for the latter. However, the presence of an excess of fluorinated acid, used for end‐functionalization, produces a reduction of the associative behavior above the overlap concentration, with the fluorinated acid acting like a surfactant. A competition may also occur between PS—and R_F—mediated micellization. Copyright © 2004 Society of Chemical Industry     

Evaluation of hydrological processes in a mountainous small basin using a quinone biomarker.

An applicability of quinone biomarker to the analysis of hillslope runoff was investigated. At first, quinone profiles of three streams as well as a hillslope runoff in a forested headwater catchment were compared. The quinone composition of hillslope runoff differed from others. Moreover, there were remarkable differences in quinone profile of hillslope runoff under different rainfall conditions. Then, the behavior of quinone biomarker during the increase and decrease of hillslope runoff after a rainfall event was examined. The fractional changes in Q-9 (H2), Q-10 (H2), Q-11, MK-6 and MK-10 suggested the effect of interflow.     

Synthesis of minerals using alternative energy sources

A technology for the synthesis of synthetic minerals (using the example of spinels) using a low-temperature plasma flame is developed. The diagnostic properties of spinels are identified.     

A fuzzy logic rule-based automatic target recognizer

Methods for modeling and managing uncertainty in computer vision systems have received increased attention in recent years. Automatic target recognition is one application area of computer vision where the demands are particularly acute. In this article, fuzzy logic is proposed as a means of handling uncertainty in an expert system structure for automatic target recognition. A new technique for logical inference is described which is well-suited for this type of application. A prototype system has been developed and tested on multisensor and temporal images. the results are compared to a similar expert system which used a numeric uncertainty calculus.     

Recursive regularization filters: design, properties, andapplications

Least squares approximation problems that are regularized with specified highpass stabilizing kernels are discussed. For each problem, there is a family of discrete regularization filters (R-filters) which allow an efficient determination of the solutions. These operators are stable symmetric lowpass filters with an adjustable scale factor. Two decomposition theorems for the z-transform of such systems are presented. One facilitates the determination of their impulse response, while the other allows an efficient implementation through successive causal and anticausal recursive filtering. A case of special interest is the design of R-filters for the first- and second-order difference operators. These results are extended for two-dimensional signals and, for illustration purposes, are applied to the problem of edge detection. This leads to a very efficient implementation (8 multiplies+10 adds per pixel) of the optimal Canny edge detector based on the use of a separable second-order R-filter     

Effect of the magnetic-flux variations on SQUID stability

The oscillation dynamics of a nonhysteretic, one-contact superconducting quantum interferometer under low-frequency modulation of an external magnetic flux has been studied. It is shown that even in the case of adiabatic, equilibrium, and nonhysteretic operation modes of a superconducting ring enclosed by a weak link, there can appear chaotic oscillations. The conditions of chaos arising have been considered analytically and numerically; mechanisms and destruction scenarios of periodic oscillations have been studied. The stochastic instability could impose limitations on the increase in sensitivity of nonhysteretic SQUIDs, which was earlier predicted to be high enough.