Ion channeling study of epitaxy of iron based Heusler alloy films on Ge(111)

We have investigated perfection of atomic rows on iron-based Heusler alloy films on Ge(111) planes by using ion channeling technique in order to find the dominant factors for the perfection. Fe₃Si/Ge(111) and Fe₂CoSi/Ge(111) have a high quality of atomic rows at the heterointerface like that of perfect crystals. Fe_3−xMn_xSi/Ge(111) (x = 0.84, 0.72 and 0.36) interfaces have imperfection of atomic rows which may be controlled by both the lattice mismatch with the Ge substrate and the Mn-Si pairs due to the site disorder in the film with the Mn content x > 0.75. Analysis of axial channeling parameters employed in this study is very useful for quantitative evaluation of perfection of atomic rows at the heterointerface.     

Measurement of MKID Performance with High-Speed and Wide-Band Readout System

Microwave kinetic inductance detectors (MKIDs) are being developed at the National Astronomical Observatory of Japan to enable precise measurements of the cosmic microwave background. One of the features of MKIDs is scalability using a frequency-division multiplexing (FDMUX) readout scheme. A digital fast fourier transform spectrometer (FFTS) is a good way to read out a number of resonance frequencies simultaneously and fully utilize the advantage of FDMUX of MKIDs. We have developed FFTS readout electronics using an ADC/DAC with 1 Gsps (sample per second) sampling rate and 270 MHz bandwidth. We measured the noise characteristics of a single MKID in the frequency range of 60 Hz–30 kHz with this readout system, and found the noise was almost equivalent to the noise measured by ordinary analog IQ down-converter readout. This indicates our FFTS electronics do not add any additional noise to the MKID readout system over the frequency range.     

Close-Packed Silicon Lens Antennas for Millimeter-Wave MKID Camera

We have been developing a large-format millimeter-wave camera based on lens-antenna-coupled microwave kinetic inductance detectors (MKIDs) for a planned telescope at Dome Fuji (3810 m a.s.l.), Antarctica. Optical coupling to the MKID incorporates double-slot antennas and a silicon lens array. To realize a large-format camera ( \(>\) 10,000 pixels), a highly integrated small-diameter lens array and fast optics are required. Lens diameters of 1.2, 2, and 3 times the target wavelength are investigated for the main beam symmetry, side-lobe level, cross-polarization level, and bandwidth, considering the effects of the surrounding lenses. In this study, we present the simulated beam pattern profiles of close-packed lens antenna and the effect of misalignment between the silicon lens and double-slot antenna. We also show the evaluations of the developed 721-pixel close-packed silicon lens array.     

Analytic Self-Consistent Condensates in Quasi-1D Superfluid Fermi Gases in the Andreev Approximation

We present an analytic method to approach Eilenberger equation and the associated Bogoliubov–de Gennes equation for quasi-1D fermionic gases. The problem of finding self-consistent inhomogeneous condensates is reduced to solving a certain class of nonlinear Schrödinger equations, whose most general solitonic solution is indeed available. Previously known solutions can be retrieved by taking appropriate limits in the parameters. The applicability of the method extends to systems with population imbalance and subject to external potential. In particular we show that fermionic zero-modes are robust against population imbalance.     

Influence of activated carbon on crevice corrosion in adsorption tower of advanced liquid processing system

ABSTRACT

The adsorption tower made of type 316L stainless steel (SS) in Multi-nuclide Removal Equipment (Advanced Liquid Processing System) which uses Ag-impregnated activated carbon (Ag AC) as an adsorbent experienced crevice corrosion. The influence of Ag AC on the crevice corrosion susceptibility and E_sp of 316L SS was investigated by performing electrochemical experiments. Crevice corrosion was observed in the specimen in contact with the Ag AC. On the other hand, there was no crevice corrosion without the Ag AC in both pH 7.4 and pH 12 solutions. Clear ennoblement of spontaneous potential (E_sp) by in contact with activated carbon was observed and that was clearly higher than the repassivation potential for crevice corrosion (E_R,CREV). Thus, the presence of the AC notably increased E_sp of 316L SS and this resulted in increased crevice corrosion susceptibility by the galvanic effect.

This paper is part of a supplementary issue from the 17th Asia-Pacific Corrosion Control Conference (APCCC-17).     

Fuel ethanol production from sweet sorghum using repeated-batch fermentation

Ethanol was efficiently produced from three varieties of sweet sorghum using repeated-batch fermentation without pasteurization or acidification. Saccharomyces cerevisiae cells could be recycled in 16 cycles of the fermentation process with good ethanol yields. This technique would make it possible to use a broader range of sweet sorghum varieties for ethanol production.     

Fates of foodborne pathogens in raw hams manufactured rapidly using a new patented method

To manufacture raw ham in an efficient manner, we recently developed a new system in which presliced pork loin was used, and the processing time was reduced to 5% of the conventional method. This study aimed to examine whether this raw ham could be as safe as ham produced by the conventional method. Pork loin spiked with enterohemorrhagic Escherichia coli serotype O157:H7, Listeria monocytogenes serotype 1/2c, Salmonella enterica serovar Enteritidis, and Staphylococcus aureus were processed using either the new or conventional method. The fate of the foodborne pathogens and behavior of hygiene indicator bacteria were examined. Whereas nitrite had disappeared during the conventional packaging process, the reduced processing time in the new system allowed for the ham to be vacuum packed with retention of the nitrite (6.9±1.2 ppm, P<0.01). This accounts for the prominent decrease in L. monocytogenes (2.3 log reduction in 35 days) and S. aureus (3.3 log reduction in 13 days) counts during storage. E. coli O157 and Salmonella Enteritidis were likely resistant to the nitrite in the ham. However, they were unable to multiply in the ham and decreased gradually as in the conventionally produced ham. The bacteriostatic nature of the raw ham was also indicated by the gradual decrease in coliforms (1.3 log reduction in 13 days) in nonspiked ham. In conclusion, the raw ham produced using presliced pork loin is practically as safe as conventionally produced raw ham. It is worth validating these results in a small-scale production setting.     

Single-walled carbon nanotube growth with non-iron-group “catalysts” by chemical vapor deposition

Various materials have been found to “catalyze” carbon nanotube growth in chemical vapor deposition (CVD) when they become nano-sized particles. These involve not only metals, such as Pd, Pt, Au, Ag, and Cu, but also semiconductors, such as Si, Ge, and SiC. Alumina and diamond nanoparticles also produce carbon nanotubes. These “catalysts”, which are better called “seeds”, can be categorized into two types: one type forms a eutectic liquid or highly-mobile alloy with carbon, and carbon atoms precipitate from the eutectic alloy; the other type remains as a solid phase and form a carbon surface layer during CVD growth. In this paper, we review recent studies of SWCNT growth with these non-iron-group materials and highlight the mechanisms involved.      

Increase of inductance ratio of flat type fault current limiter with high‐Tc superconducting disk

Fault current limiters (FCLs) are expected to reduce fault current and improve stability of power systems. A flat type fault current limiter consisting of the pancake primary winding and a high‐T_c superconducting (HTS) disk was proposed as a modified version of a conventional magnetic shield type of the FCL with the superconducting cylinder. The flat type FCL has the advantage of being manufactured smaller than the cylinder type FCL. It is pointed out, from a magnetic field analysis, that the volume of the flat type FCL is smaller than that of the cylinder type FCL with same magnitude of the limiting inductance. Further, the magnetic field analysis suggests that a high inductance ratio can be realized by radially enlarging both the primary winding and the HTS disk, stacking the FCL modules in layers and sandwiching the primary winding with superconducting disks. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.