An efficient 0.04-nm apodized fiber Bragg grating and its application to narrow-band spectral filtering

A narrow-band apodized fiber Bragg grating was fabricated with a phase mask method that incorporated a fluorescence monitoring technique. The grating length was 100 mm and the 3-dB reduced bandwidth was as small as 0.04 nm. The 20-dB reduced bandwidth was 0.1 nm at a center wavelength of 1554 mm. A single longitudinal oscillation mode of a 10-GHz pulse train from a mode-locked fiber laser was successfully extracted using the grating.     

Mass mating method in combination with G418- and aureobasidin A-resistance markers for efficient selection of hybrids from homothallic strains in Saccharomyces cerevisiae

We have developed a mass mating method using the spore suspensions of homothallic yeasts of Saccharomyces cerevisiae in combination with dominant selective drug resistance markers, Tn601(903) against geneticin and AUR1-C against aureobasidin A for the selection of the hybrids. To examine the effectiveness of these markers in the mass mating method, each marker was introduced into a homothallic wine yeast. Using a mixed culture of spore suspensions from the resultant transformants, many hybrids were screened by the drug resistance markers. This method is more practical than the spore-to-spore mating method because it does not require the use of a micromanipulator and many hybrids are obtained at one time. The resultant hybrids could be utilized for industrial brewing because plasmids, which are used to confer resistance markers, are easily eliminated from the hybrids by cultivation in a medium without drugs. We propose that the mass mating method using spore suspensions in combination with dominant selective geneticin- and aureobasidin A-resistance markers is useful for the selection of hybrids from industrial homothallic yeasts.     

10 Gbit/s pseudorandom dark soliton data transmission over 1200 km

A 10 Gbit/s pseudorandom (PR) dark soliton data signal has been successfully transmitted over 1200 km for the first time. The dark soliton source was a 1.53 μm DFB LD and was modulated with a push-pull Mach-Zehnder LiNbO₃ intensity modulator. A T-flip-flop circuit was used to generate the PR dark soliton. A one-bit-shifting scheme with a Mach-Zehnder interferometer was used to convert the dark soliton train into a conventional NRZ signal     

Application of an electron backscatter diffraction pattern to Cu damascene-fabricated interconnections filled by a high-pressure anneal process

The microstructure of Cu interconnections fabricated by high-pressure annealing was evaluated using a field emission scanning electron microscope/electron backscatter diffraction pattern (FE-SEM/EBSP) technique, and the results are compared with as-deposited and normally annealed Cu films. The results show some grains extending from the bulk field to the via regions in the case of the high-pressure annealed Cu films. The existence of via holes was also observed, in which all grains were (111) oriented. This indicates that the high-pressure annealing process enables the Cu that in-fills the via holes to develop into favorable microstructures, i.e., single-crystal and with (111) orientation.     

Probabilistic fault grading based on activation checking and observability analysis

A simplified probabilistic fault grading method is described. The concept of propagation probability is introduced in place of the sensitization probability of STAFAN, and the empirical parameters of STAFAN are eliminated. The division of input vectors into subsets is monitored by the activation or toggle rate. The accuracy of the method is examined for fault coverage estimation and for predicting the undetected faults.     

Colored Fluorescent Silk Made by Transgenic Silkworms

Silk is a protein fiber used to weave fabrics and as a biomaterial in medical applications. Recently, genetically modified silks have been produced from transgenic silkworms. In the present study, transgenic silkworms for the mass production of three colors of fluorescent silks, (green, red, and orange) are generated using a vector originating from the fibroin H chain gene and a classical breeding method. The suitability of the recombinant silks for making fabrics is investigated by harvesting large amounts of the cocoons, obtained from rearing over 20 thousand silkworms. The application of low temperature and a weakly alkaline solution for cooking and reeling enables the production of silk fiber without loss of color. The maximum strain tolerated and Young's modulus of the fluorescent silks are similar to those of ordinary silk, although the maximum stress value of the recombinant silk is slightly lower than that of the control. Fabrics with fluorescent color are demonstrated using the recombinant silk, with the color persisting for over two years. The results indicate that large amounts of genetically modified silk can be made by transgenic silkworms, and the silk is applicable as functional silk fiber for making fabrics and for use in medical applications.     

A novel l-amino acid ligase from bacillus licheniformis

l-Amino acid alpha-ligase (EC 6.3.2.28) catalyzed formation of alpha-peptide bond in unprotected l-amino acids in an ATP-dependent manner. BL00235 gene in Bacillus licheniformis NBRC12200 coded as a new l-amino acid ligase. BL00235 substrate specificity was strict; only methionine or leucine was acceptable as dipeptide N-terminal residues.     

Study of Pt electrode dissolution in H2O2-containing H2SO4 solution using an electrochemical quartz crystal microbalance

Pt electrode dissolution has been investigated using an electrochemical quartz crystal microbalance (EQCM) in H₂O₂-containing 0.5 mol dm⁻³ H₂SO₄. The Pt electrode weight-loss of ca. 0.4 μg cm⁻² is observed during nine potential sweeps between 0.01 and 1.36 V vs. RHE. In contrast, the Pt electrode weight-loss is negligible without H₂O₂ (<0.05 μg cm⁻²). To support the EQCM results, the weight-decrease amounts of a Pt disk electrode and amounts of Pt dissolved in the solutions were measured after similar successive potential cycles. As a result, these results agreed well with the EQCM results. Furthermore, the H₂O₂ concentration dependence of the Pt weight-decrease rate was assessed by successive potential steps. These EQCM data indicated that the increase in H₂O₂ accelerates the Pt dissolution. Based on these results, H₂O₂ is known to be a major factor contributing to the Pt dissolution.     

Kinetics of methane reforming over Ru/γ-Al2O3-catalyzed metallic foam at 650-900 °C for solar receiver-absorbers

The kinetics of methane reforming over Ru/γ-Al₂O₃-catalyzed high porosity Ni-Cr-Al foam were examined at temperatures of 650-900 °C in a quartz tubular reactor using an electric furnace. The kinetic data were analyzed by four different types of kinetic models based on the basic, Eley-Rideal, Langmuir-Hinshelwood, and stepwise mechanisms. Validation of the kinetic models was carried out by calculating the determination coefficient r² between the predicted and the experimental results for each model. The absolute average deviation percentage (AAD%) between the predicted and the experimental results was also estimated for each model. The kinetic model based on the reversible stepwise mechanism provided the best prediction of the experimental reforming rates with an AAD value of 6% in the range 650-850 °C.