Synthesis of polychloroprene–silica composites by sol‐gel method in the presence of modified polychloroprene containing triethoxysilyl group

Triethoxysilyl‐modified polychloroprene (CR) latex was synthesized by the emulsion copolymerization of 2‐(3‐triethoxysilylpropyl)‐1,3‐butadiene with chloroprene. This latex was mixed with unmodified CR latex and tetraethoxysilane to obtain CR–silica composites by sol‐gel reaction in the latex. SEM observation showed that the silica particles in unvulcanized composites have various diameters ranging from 0.1 to 0.6 μ m, and their size became larger with the decrease of the silica content. Vulcanized CR–silica composites showed that the tensile modulus and tear strength improved with an increase of the amount of modified CR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 1545–1552, 2005     

Photoreaction of Titanium-Based Metal-organic Compounds for Ceramic Fine Patterning

The photoreaction of metal-organic compounds prepared by the chemical modification of metal alkoxides was investigated for the patterning of ceramic films. The chemical stability and photoreactivity of these compounds were found to be greatly influenced by the kind of chemical additive applied during the syntheses of the precursor solutions. In this study, the photoreaction of the precursor thin films prepared by the addition of alkanolamines was achieved by tuning the wavelength of the incident UV light. The decomposition of the organic moieties of the percursors was clearly observed in IR spectra during UV irradiation. Furthermore, the spectrum of the titania precursor film in the visible and ultraviolet regions (UV-vis) changed in accordance with the irradiation time. The photolithography of the titanium precursor pattern was successfully achieved by means of these techniques.     

High-precision voltage-measuring method using fast sampled data for electric power systems

Control and protection equipment in power systems requires higher sensitivity and operational reliability to meet today's changing power system requirements. The voltage-measuring deviation requirement for advanced voltage and var control equipment is less than 0.1 percent under conditions of harmonic distortion in the voltage waveform and power-system frequency variation. Studies on digital signal processing suitable for electric power systems showed that these requirements are satisfied using fast sampling and very fast 32-bit floating point operations by a Digital Signal Processor (DSP). This paper describes the design philosophy of a high-precision power system voltage-measuring method using fast sampled data. In addition, total voltage-measuring deviation characteristics under a combination of the techniques are described along with digital filter characteristics, frequency-measuring deviation characteristics, frequency variation versus gain-compensation characteristics of a digital filter, and peak value operating principles.     

Rough Surface Effects on the p-Wave Fermi Superfluids

Rough surface effects on p-wave Fermi superfluids are discussed on the basis of our recently proposed quasi-classical theory that can treat in a unified way the surface scattering ranging from the specular limit to the diffusive limit. We show how the transition temperature of the ABM state in a slab geometry depends on the surface roughness. In the diffusive limit, our result agrees with Kjäldmann et al. We consider the BW state, the ABM state and the polar state in a half-infinite geometry with a plane rough surface and discuss the self-consistent order parameter and the surface density of states at low temperatures. The rough surface effects on the Andreev scattering in the BW state are also discussed within the same framework.     

Gas transport in poly(vinyl-p-isopropylbenzoate): Comparison and correlation with some other poly(vinyl esters)

Gas permeability in poly(vinyl-p-isopropylbenzoate) (PVp-i-PrB) was determined by a timelag method. The transport properties were discussed from comparison with the permeability data of other poly(vinyl esters), which were studied previously. All these polymers are structurally related, and the size of a side group or the position of its substituent was changed systematically. The isopropyl group of PVp-i-PrB is attached at the para position of a phenyl ring and is the largest in size. As a result gas diffusivity and therefore permeability were increased. The effect of the substituent on gas diffusivity was explained as it increases the interchain and intrachain distances. The discussion was supported from the comparison of the density data between PVp-i-PrB and other poly(vinyl esters). The diffusion coefficients of six glassy poly(vinyl esters) were correlated at their T_g and good correlations were shown to the free volume and its fraction. On the other hand, gas solubility was little affected by the change of an alkyl group on a phenyl ring. The solubility data of PVp-i-PrB and poly(vinyl benzoate) were shown to be clearly correlated with the critical properties of the penetrants. © 1995 John Wiley & Sons, Inc.     

A New Temperature Compensating Method for Logarithmic Amplifier

A new method of temperature compensation for a dc logarithmic amplifier is presented. By this method temperature effect on both parallel shift and slope variance of log I vs. VBE curve can be compensated easily by using only one compensating resistor of copper wire wound type. (hereafter called parallel and slope compensations.) An absolute compensation condition can be determined for each type of logarithmic transistors, like silicon NPN, germanium PNP irrespective of current measuring range. The temperature dependence of the logarithmic amplifier is reduced to 0.01 decade for the temperature range from 0°C to 50°C and the current range from 10-11 to 10-3A.     

Aging and thermal stability of Mg/SiC and Mg/Y2O3 reflection multilayers in the 25-35 nm region

Reflection measurements in the 25-35 nm region were made for Mg/SiC and Mg/Y2O3 multilayers kept in a low-humidity atmosphere for 4 or 5 years. Aged Mg/SiC multilayers keep their reflectances, and the reflectance value at 31.2 nm is 0.44 at 10 degrees of the normal angle of incidence. Aged Mg/Y2O3 multilayers change reflectance as top layer materials, and the best value at 30.1 nm is 0.40 at 10 degrees. Reflection measurements are also made for Mg-based multilayers that are annealed from room temperature to 400 degrees C at 50 degrees C intervals. Both multilayers keep their reflectance at annealing temperatures of 200 degrees C. These results suggest that both Mg-based multilayers can be applied to practical optics.     

Nanoporous reactor with tunable selectivity on alkylation of ethylbenzene

As nanoporous reactor, mesoporous silicates containing aluminum acidic site with n(Si)/n(Al) ratio up to 7 (AISBA-15) were prepared through a simple one-pot synthesis, which was recently developed by parts of us. The obtained materials were satisfactorily characterized by XRD and nitrogen adsorption/desorption and have regularly arranged hexagonal structures with pore diameters in the 9.6-11.8-nm range. The density and strength of the acid sites were determined using temperature-programmed desorption (TPD) of pyridine and controlled distribution between weak, moderate, and strong acid sites was demonstrated. The alkylation of ethylbenzene in a fixed-bed flow-type reactor using the AISBA-15 nanoporous reactor was carried out under various conditions such as temperature, feed ratio, flow rate, and time on stream. Interestingly, perfect regioselectivity between the m-isomer and the o-/p-isomers of diethylbenzene was achieved, where 100% selectivity of the m-isomer or the o-/p-isomers can be obtained by simply tuning the reaction temperature by using AISBA-15 catalyst with appropriate aluminum content.     

Uniformity of flow from sheeting dies

A numerical method for analyzing the uniformity of flow from sheeting dies is presented. The method assumes that the flow is isothermal and that the material is a power law fluid. A uniformity index is defined and methods are presented which enable die dimensions to be established which will result in a specified uniformity at particular flow rates and pressure drops. The analysis shows that the flow index “n” of the power law is the key parameter determining the uniformity of flow from a sheeting die.