The preparation of copper fine particle paste and its application as the inner electrode material of a multilayered ceramic capacitor

Well size-controlled copper fine particles (diameter: 100-300?nm) were used as the inner electrode material of multilayered ceramic capacitors (MLCCs). The particles were dispersed in terpineol to form a printing paste with 50?wt% copper particles. The MLCC precursor modules prepared by the layer-by-layer printing of copper and BaTiO(3) particles were cosintered. Detailed observation of the particles, paste, and MLCCs before and after sintering was carried out by electron microscopy. The sintering temperature of Cu-MLCC was as low as 960?°C. The permittivity of these MLCCs was successfully measured with the copper inner layers.     

A consistent grayscale‐free topology optimization method using the level‐set method and zero‐level boundary tracking mesh

This paper proposes a level‐set based topology optimization method incorporating a boundary tracking mesh generating method and nonlinear programming. Because the boundary tracking mesh is always conformed to the structural boundary, good approximation to the boundary is maintained during optimization; therefore, structural design problems are solved completely without grayscale material. Previously, we introduced the boundary tracking mesh generating method into level‐set based topology optimization and updated the design variables by solving the level‐set equation. In order to adapt our previous method to general structural optimization frameworks, the incorporation of the method with nonlinear programming is investigated in this paper. To successfully incorporate nonlinear programming, the optimization problem is regularized using a double‐well potential. Furthermore, the sensitivities with respect to the design variables are strictly derived to maintain consistency in mathematical programming. We expect the investigation to open up a new class of grayscale‐free topology optimization. The usefulness of the proposed method is demonstrated using several numerical examples targeting two‐dimensional compliant mechanism and metallic waveguide design problems. Copyright © 2014 John Wiley & Sons, Ltd.     

Factors affecting soluble selenium removal by a selenate-reducing bacterium Bacillus sp. SF-1

High concentrations of soluble selenium, selenate and selenite, have acute and chronic toxicity toward living things. With the aim of developing a biological process for selenium removal, the effects of a variety of parameters on the reduction of soluble selenium by a Bacillus sp. strain SF-1, which is capable of reductively transforming selenate into selenite and, subsequently, into nontoxic insoluble elemental selenium, were studied. The bacterial strain could effectively reduce 20 mM of selenate to selenite and 2 mM of selenite to elemental selenium in the presence of an appropriate carbon source and in the absence of oxygen. The reduction rate of selenate to selenite was much higher than that of selenite to elemental selenium, resulting in the transient accumulation of selenite during selenate reduction. The selenate reduction rate increased with increases in the selenate concentration up to 20 mM, while the rate of selenite reduction decreased sharply at selenite concentrations of more than 2 mM. The elemental selenium transformed from selenate via selenite was found both inside and outside the cells. Bacillus sp. SF-1 was able to utilize a variety of organic acids or sugars as a carbon source in selenate reduction. Although the copresence of sulfate did not inhibit selenate reduction, it was completely inhibited by some other oxyanions, including nitrate. A model sequencing batch system using the bacterial strain was developed and exhibited good performance in the treatment of wastewater containing high concentrations of selenate.     

Dietary corn germ containing phytic acid prevents pork meat lipid oxidation while maintaining normal animal growth performance

The effects of dietary defatted corn germ meal (DCGM) containing phytic acid (PA) on pig health during development and on its Longissimus dorsi m. (LD) lipid oxidative stability has been evaluated. Rations of DCGM were prepared at the level of substitution of 0%, 10%, 20% and 40% and offered to twenty four animals of Landrace x Large White crossbreds throughout 25 days before slaughtering. Animals were sacrificed at an average weight of 91.24 kg (±0.950) and samples for meat lipid oxidation analysis were taken after seven days under refrigeration at 3 °C. Animals fed with DCGM did not show any significant difference, in comparison to the control, in carcass characteristics, such as cold carcass weight, backfat depth, muscle depth, lean meat percentage and carcass dress yielding (p  0.05). Finally, no difference in meat proximate chemical composition was detected solely arising from lipid oxidation since LD from DCGM-treated pigs revealed an inhibition of 63.0%.     

A 39-to-45-Gbit/s multi-data-rate clock and data recovery circuit with a robust lock detector

We describe a 40-Gbit/s-class clock and data recovery (CDR) circuit with an extremely wide pull-in range. A Darlington-type voltage-controlled oscillator (VCO) is newly designed to cover the STM-256/OC-768 full-rate-clock frequencies with a wide frequency margin. We also describe a new lock detector using an exclusive-NOR gate. The CDR IC was fabricated using InP/InGaAs HBTs. Error-free operation and wide eye opening were confirmed for 40-, 43-, and 45-Gbit/s PRBS with a word length of 2/sup 31/ - 1. We attached a frequency search and phase control (FSPC) circuit to the chip as a new frequency acquisition aid, and this allows the CDR circuit to pull in throughout a 39-45-Gbit/s range. The peak-to-peak and rms jitter of the recovered clock were 3.6 and 0.48 ps, respectively.     

Optimal Fourier spectrum estimation from the bispectrum

The results of an extensive computer simulation study are presented in this paper. Optimal parameter values are determined for previously derived weighted least squares algorithms used to estimate an object's Fourier spectrum from its bispectrum. The relative quality of phase and power spectra estimated from bispectra is discussed, and it is shown that the useful portion of the bispectrum includes elements with offsets larger than the seeing cutoff spatial frequency.     

Experimental determination of gain compression factors of a DFBlaser in the presence of TM light injection

Compared to direct current modulation, an optical modulation scheme of laser diodes exhibits no rolling off characteristics due to the electrical parasitics existing in the laser diodes. In particular, in the TM light injection scheme, no injection locking phenomena take place. A number of applications of TM light injection have been reported. In relation to these, determining the gain compression factors of laser diodes in the presence of TM light injection is essential. A new technique for determining these factors is presented. The technique is shown to be viable for measuring the gain compression of distributed feedback (DFB) lasers     

Desiccation survival of Listeria monocytogenes and other potential foodborne pathogens on stainless steel surfaces is affected by different food soils

Food processing environments are suspected to be the primary source of Listeria monocytogenes contamination of foods. We investigated the survival of L. monocytogenes on stainless steel that was soiled with food components (minced tuna, ground pork, and cabbage) followed by dehydration. Stainless steel coupons were inoculated with 10⁷ CFU/coupon and stored up to 30 days. In comparison with Staphylococcus aureus and Salmonella Typhimurium, L. monocytogenes demonstrated the highest survivability where about 3 log CFU/coupon remained at the end of the experimental period. While survival during the early storage period was markedly affected by both food-component attachment and food type, a long dehydration period diminished the effect of those.