Development of a 400 kJ Nb3Sn superconducting magnet for an SMES system

An Nb₃Sn superconducting magnet to store 400 kJ was developed as a unit magnet for a 2.4-MJ SMES system used for stabilization studies of electrical power systems. The superconducting magnet consists of a cryostat and an Nb₃Sn coil. The dimensions of the coil are: 340 mm inner diameter, 700 mm outer diameter and 177 mm axial length. The pool-cooled coil is a stack of 20 Nb₃Sn double pancakes, and the cooling channels are aligned between pancake coils. To reduce Joule loss in electrical power converters, the maximum operating current of the coil is designed to be 350 A, which is one order of magnitude less than the operating currents of similar scale coils for pulse use. The conductor is an Nb₃Sn monolithic conductor with cross section 1.50 × 2.38 mm. For good superconducting stability and high dielectric strength of the coil, the Nb₃Sn double pancakes were wound by the react-and-wind technique. Operation of dc current to 105% (367.5 A) of the design operating current was achieved without quench. After the whole of the coil was exposed out of liquid helium, the coil did not quench under 120 A current operation for more than 2 hours. It was verified that the coil was stable for the SMES system. © 1998 Scripta Technica, Inc. Electr Eng Jpn, 121(3): 44–52, 1997     

Asymmetrical modulation and overmodulation of parallel-connected NPC-PWM inverters

The neutral point clamped (NPC)-PWM inverter has significant advantages, such as its ability to operate motors with nearly sinusoidal current waveforms. For this reason, in larger-capacity inverter systems, NPC-PWM inverters using GTOs and the like have been put into practical use, because of great advantages to large-capacity ac motor drives, such as lower ripple currents and higher output voltages. With the spread of applications, inverters of still larger capacity are expected. However, since the capacities of such switching devices are insufficient, a certain technique and controlling method are proposed for the parallel connection of NPC inverters. In this paper, conventional modulation techniques are extended to improve the inverter characteristics; asymmetrical modulation and overmodulation techniques are introduced for the parallel-connected NPC inverter. In the proposed modulation strategies, the waveforms become more complicated, so that it is difficult to analyze the output waveforms. For those waveforms, an analytical waveform analysis method using the switching function is proposed. With such a method, the physical meaning of harmonic generation can be realized to some extent. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(2): 49–58, 1997     

Preference for Japanese complexion color under illumination

To find the chromaticity coordinates of the “Preferred Complexion of Japanese Woman” under illumination, subjective estimation experiments were conducted on the complexions of 3 female models under each of 40 colors of illumination. The chromaticity coordinates of “Preferred Complexion” for each model were about the same together. The average chromaticity coordinates of 3 female models were (u′, v′) = (0.2425, 0.4895) under the standard illuminant D65. The “Preferred Complexion of Japanese Woman” in this experiment was compared with the “Preferred Complexion of Caucasian Woman” studied by Sanders. The “Preferred Complexion of Japanese Woman” was shifted to a slightly higher saturation and reddish in hue, compared with the actual complexion of “Japanese Woman.” On the other hand, the “Preferred Complexion of Caucasian Woman” was orange in hue, the same as the actual complexion of “Caucasian Woman.” The color shift of saturation of the “Caucasian Woman” was 3.5 times as large as that of the “Japanese Woman.” © 1997 John Wiley & Sons, Inc. Col Res Appl, 22, 269–274, 1997     

Characterization of an Exo-Maltotetraose-forming Amylase of Pseudomonas stutzeri and Application in p-Nitrophenyl β-D-Galactosyl-α-Maltooligosaccharides Production

Some kinetic characteristics and hydrolytic action patterns on various β-D -galactosyl-maltooligosaccharides (Gal-Gn), ranging in size from D.P. (degree of polymerization) 5 to 8, of an exo-maltotetraose-forming amylase of Pseudomonas stutzeri (G4-amylase) were examined to produce a few p-nitrophenyl β-D -galactosyl-α-maltooligosaccharides (Gal-GnP, n = 4,5). The relative hydrolytic reaction rates for larger Gal-Gn by the enzyme were larger than those for smaller saccharides tough the values for unmodified linear maltooligosachharides were almost same. Michaelis constants (Km) for hydrolysis of Gal-G4, Gal-G5, Gal-G6 and Gal-G7 by the enzyme were 1.3, 1.9, 1.3 and 1.3mM, and apparent molecular activities (ko) for these saccharides were 5.9, 38, 91 and 126s⁻¹, respectively. The values of ko/Km for them were remarkably smaller than those for unmodified linear maltooligosaccharides. The G4-amylase cleaved 2 points of the α-1,4-glucosidic linkage in β-1,4-Gal-G4 to give β-1,4-Gal-G2 and -Gal-G3 in the molar ratio of 3:1, whereas the enzyme attacked 3 points of the linkage in β-1,4-Gal-G5, -Gal-G6 and -Gal-G7 to form β-1,4-Gal-G2,-Gal-G3 and Gal-G4 in the molar ratios of 2:5:1, 1:3:6 and 1:3:6, in the early stage of the reaction, respectively. On the other hand, the enzyme showed no action on β-1,6-Gal-G4 and formed β-1,6-Gal-G4 solely from β-1,6-Gal-G5, and β-1,6-Gal-G4 and -Gal-G5 were from β-1,6-Gal-G6 and -Gal-G7 in the ratios of 8:1 and 2:1, respectively. The enzyme also catalyzed the transfer action to produce Gal-G3P, Gal-G4P and Gal-G5P, of which the formation ratio was coincided well with the hydrolytic action pattern on each Gal-Gn, from Gal-Gn tested as a donor and p-nitrophenyl α-glucoside (GP) as an acceptor in an aqueous solution containing 40% (v/v) methanol. By using this novel reaction, Gal-G5P is now producing on an industrial scale to apply as a substrate for the assay of human α-amylase.     

Raman Spectroscopy of Laser‐Shocked Nitrobenzene

A technique for in situ Raman spectroscopy of laser‐shocked nitrobenzene was developed. Raman spectra of shocked nitrobenzene are obtained up to ∼3.5 GPa, and peak shifts at particular frequencies are observed. The shifts are plotted as a function of density and compared with the data under isothermal compression. Both data provide the same results. This indicates that the numbers of peak shifts of nitrobenzene depend solely on material density.     

High-melt-strength polypropylene with electron beam irradiation in the presence of polyfunctional monomers

High-melt-strength polypropylene (PP) was achieved with irradiation by an electron beam generated from an accelerator in the presence of polyfunctional monomers (PFM). Among 16 PFMs, the relatively shorter molecular chain bifunctional monomers such as 1,4-butanediol diacrylate (BDDA) and 1,6-hexanediol diacrylate (HDDA) were the most effective for enhancing the melt strength of PP. The concentration and dose of the HDDA to obtain the high melt strength PP in irradiation under nitrogen gas atmosphere were 1.5 mmol/100 g PP and 1 kGy, respectively. DSC measurement and dynamic mechanical analysis showed that the thermal behavior of the high-melt-strength PP was different from that of the original PP. Crystallinity and crystallization temperature during cooling after heating were lower and higher in high melt strength PP than original PP, respectively. Elongational viscosity at 180°C of the high-melt-strength PP showed a remarkable increase at a certain elongational time with constant strain rate, demonstrating the typical property of high-melt-strength samples. This implies that a few higher molecular chains of PP, formed by intermolecular combination of its chain by HDDA in irradiation, give higher melt strength to induce entanglement of molecular chains. © 1996 John Wiley & Sons, Inc.     

Microbial synthesis and properties of poly(3-hydroxybutyrate-co-4-hydroxybutyrate)

Microbial synthesis of copolymers of [R]-3-hydroxybutyrate (3HB) and 4-hydroxybutyrate (4HB), P(3HB-co-4HB), by Alcaligenes eutrophus, Alcaligenes latus, and Comamonas acidovorans from various carbon sources has been studied. The copolyester compositions varied from 0 to 100 mol% 4HB, depending on the microorganism and the combination of carbon substrates supplied. The thermal and physical properties of compositions with 0–100 mol% 4HB were investigated. The copolyesters represented a wide variety of polymeric materials, from hard crystalline plastic to very elastic rubbers, depending on composition. The copolyester films with high 4HB fractions (64–100 mol% 4HB) exhibited the characteristics of a thermoplastic elastomer, and the tensile strength increased from 17 to 104 MPa as the 4HB fraction increased. The enzymatic degradation of P(3HB-co-4HB) films was studied in an aqueous solution of extracellular polyhydroxybutyrate (PHB) depolymerase from Alcaligenes faecalis or lipase from Rhizopus delemer. The erosion rate of P(3HB-co-4HB) films was strongly dependent on the copolymer composition. In addition, environmental degradation of P(3HB-co-4HB) films in sea water was investigated.     

Oral Squamous Cell Carcinoma Contributes to Differentiation of Monocyte-Derived Tumor-Associated Macrophages via PAI-1 and IL-8 Production

Tumor-associated macrophages (TAMs) promote cancer cell proliferation and metastasis, as well as anti-tumor immune suppression. Recent studies have shown that tumors enhance the recruitment and differentiation of TAMs, but the detailed mechanisms have not been clarified. We thus examined the influence of cancer cells on the differentiation of monocytes to TAM subsets, including CD163⁺, CD204⁺, and CD206⁺ cells, in oral squamous cell carcinoma (OSCC) using immunohistochemistry, flow cytometry, and a cytokine array. Furthermore, we investigated the effect of OSCC cells (HSC-2, SQUU-A, and SQUU-B cells) on the differentiation of purified CD14⁺ cells to TAM subsets. The localization patterns of CD163⁺, CD204⁺, and CD206⁺ in OSCC sections were quite different. The expression of CD206 on CD14⁺ cells was significantly increased after the co-culture with OSCC cell lines, while the expressions of CD163 and CD204 on CD14⁺ cells showed no change. High concentrations of plasminogen activator inhibitor-1 (PAI-1) and interleukin-8 (IL-8) were detected in the conditioned medium of OSCC cell lines. PAI-1 and IL-8 stimulated CD14⁺ cells to express CD206. Moreover, there were positive correlations among the numbers of CD206⁺, PAI-1⁺, and IL-8⁺ cells in OSCC sections. These results suggest that PAI-1 and IL-8 produced by OSCC contribute to the differentiation of monocytes to CD206⁺ TAMs.