Evaluation and discussion of disturbance observer‐based anti‐slip/skip readhesion control for electric train

The improvement of adhesion characteristics is very important for electric trains. The drive system of electric trains must have fine anti‐slip and anti‐skid readhesion controls. In order to achieve the required adhesion, we have already proposed an anti‐slip/skid readhesion control system based on disturbance observer and sensorless vector control. Moreover, we have already applied the proposed method to actual electric multiple unit trains Series 205‐5000. In this paper, using the experimental results of Series 205‐5000 and the numerical simulation results, we evaluate the proposed anti‐slip/skid readhesion control system and confirm that the system has the desired driving wheel torque response. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(4): 55–64, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20834     

A novel structure of ceramics electrolyte for future lithium battery

In order to fabricate large scale all-solid-state Li battery, we suggested a novel structure of solid electrolyte, which is composed of porous electrolyte supported by honeycomb-type electrolyte. A possibility of fabrication of the honeycomb-supported porous electrolyte and a compatibility of this structure with all-solid-state battery were examined using LLT (Li_0.35La_0.55TiO₃) solid electrolyte which is one of the anticipated solid electrolytes due to its high Li ion conductivity. A porous layer membrane with 3 dimensionally ordered (3DOM) macroporous structure was prepared by a colloidal crystal templating method. The porous honeycomb was fabricated by pushing the membrane into holes of honycomb using a needle followed by calcination. The 3DOM membrane and honeycmb electrolyte were sintered well each other. After filling the 3DOM pores with LiMn₂O₄ cathode material, the compatibility of this novel porous honeycomb electrolyte with all-solid-state battery was examined. The LiMn₂O₄/porous honeycomb cell clearly demonstrated charge and discharge behaviors, indicating the porous honeycomb structure can be applied to the all-solid-state battery. The discharge capacity was 71 mA h g⁻¹ (1.3 mA h cm⁻²) at 30 °C.     

Chemical constituents of the leaves of rabbiteye blueberry (Vaccinium ashei) and characterisation of polymeric proanthocyanidins containing phenylpropanoid units and A-type linkages

Chemical constituents of the leaves of rabbiteye blueberry (Vaccinium ashei READE) were investigated in detail. The major phenolic components were caffeoyl quinic acids, flavonol glycosides, flavan-3-ols and proanthocyanidins. Catechins and proanthocyanidins having additional phenylpropanoid units, such as cinchonains, kandelins and mururins, characterised the polyphenols of this plant. Among them, vaccinin A, an isomer of mururin A, was found to be a new compound, and the structure was characterised by spectroscopic methods. The most abundant polyphenols (11.3% of freeze-dried leaves) were oligomeric proanthocyanidins. Thiol degradation with mercaptoethanol indicated that the polymer was constituted of (+)-catechin and (−)-epicatechin as the terminal units and (−)-epicatechin, procyanidin A-2, and cinchonains Ia and Ib as the extension units. Mass spectral analysis suggested the presence of at least dodecamers with A-type linkages and phenylpropanoid moieties.     

A 6.6‐kV transformerless STATCOM based on a five‐level diode‐clamped converter. Experiments using a three‐phase laboratory model rated at 200 V and 10 kVA

This paper discusses a 6.6‐kV transformerless STATCOM intended for installation on industrial and utility distribution systems in the near future. In addition, this paper provides experimental results obtained from a laboratory model rate at 200 V and 10 kVA. The authors propose such a control method as to superimpose a sixth harmonic zero‐sequence component on each of three‐phase voltage references. This helps to stabilize the voltage of the inner midpoint in the DC link. As a result, the laboratory model installs two bidirectional buck‐boost choppers on the DC link for the purpose of stabilizing the voltages of two outer midpoints. Experimental results obtained from the laboratory model verify the validity of the system design, giving promise of the viability of the 6.6‐kV transformerless STATCOM. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(2): 60–68, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20733     

Chemistry,Properties, and in Vitro and in Vivo Applications of 2′‐O‐Methoxyethyl‐4′‐thioRNA,a Novel Hybrid Type of Chemically Modified RNA

We report the synthesis, properties, and in vitro and in vivo applications of 2′‐O‐methoxyethyl‐4′‐thioRNA (MOE‐SRNA), a novel type of hybrid chemically modified RNA. In its hybridization with complementary RNA, MOE‐SRNA showed a moderate improvement of T_m value (+3.4 °C relative to an RNA:RNA duplex). However, the results of a comprehensive comparison of the nuclease stability of MOE‐SRNA relative to 2′‐O‐methoxyethylRNA (MOERNA), 2′‐O‐methyl‐4′‐thioRNA (Me‐SRNA), 2′‐O‐methylRNA (MeRNA), 4′‐thioRNA (SRNA), and natural RNA revealed that MOE‐SRNA had the highest stability (t_1/2>48 h in human plasma). Because of the favorable properties of MOE‐SRNA, we evaluated its in vitro and in vivo potencies as an anti‐microRNA oligonucleotide against miR‐21. Although the in vitro potency of MOE‐SRNA was moderate, its in vivo potency was significant for the suppression of tumor growth (similar to that of MOERNA).     

Influence of addition of styrene–ethylene/butylene–styrene copolymer on rheological,mechanical, and tribological properties of polyamide nanocomposites

To develop new tribomaterials for mechanical sliding parts, investigations were carried out on the influence of adding styrene–ethylene/butylene–styrene block copolymer (SEBS) on the rheological, mechanical, and tribological properties of polyamide 6 (PA6) nanocomposite, which is a commercial product of layered silicate (clay) filled polyamide 6 (PA6/Clay). Two kinds of block copolymers, unmodified SEBS (SEBS) and maleic anhydride‐grafted SEBS (SEBS‐g‐MA), were added with PA6/Clay nanocomposite. Dynamic viscoelastic properties in the molten state of these nanocomposites and their tensile, impact, and tribological properties of these nanocomposites were evaluated. Dynamic viscoelastic properties were found to increase with the addition of SEBS and were influenced, in particular, by block copolymers containing SEBS‐g‐MA. Influence of the addition of SEBS on mechanical properties of these systems differed for each mechanical property. Although tensile properties decreased with SEBS, Izod impact properties were improved with the addition of SEBS‐g‐MA. Tribological properties were improved with the addition of block copolymer, and the influence of the amount of addition was higher than the type of block copolymer used. These results indicate that new tribomaterials developed have sufficient balance amongst moldability, mechanical, and tribological properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers     

Spin-current-driven thermoelectric coating

Energy harvesting technologies, which generate electricity from environmental energy, have been attracting great interest because of their potential to power ubiquitously deployed sensor networks and mobile electronics. Of these technologies, thermoelectric (TE) conversion is a particularly promising candidate, because it can directly generate electricity from the thermal energy that is available in various places. Here we show a novel TE concept based on the spin Seebeck effect, called 'spin-thermoelectric (STE) coating', which is characterized by a simple film structure, convenient scaling capability, and easy fabrication. The STE coating, with a 60-nm-thick bismuth-substituted yttrium iron garnet (Bi:YIG) film, is applied by means of a highly efficient process on a non-magnetic substrate. Notably, spin-current-driven TE conversion is successfully demonstrated under a temperature gradient perpendicular to such an ultrathin STE-coating layer (amounting to only 0.01% of the total sample thickness). We also show that the STE coating is applicable even on glass surfaces with amorphous structures. Such a versatile implementation of the TE function may pave the way for novel applications making full use of omnipresent heat.     

Biodesulfurization of alkylated forms of dibenzothiophene and benzothiophene by Sphingomonas subarctica T7b

Sphingomonas subarctica T7b was isolated from soil in Toyotomi, Hokkaido, Japan as an organism capable of desulfurizing aromatic hydrocarbons in light gas oil (LGO) through enrichment culture. S. subarctica T7b could grow on mineral salt sulfur-free (MSSF) medium with the n-tetradecane oil phase containing dibenzothiophene (DBT), alkyl dibenzothiophenes (alkyl DBTs) or alkyl benzothiophenes (alkyl BTs) as the sole sulfur source and desulfurize these compounds, but could not utilize the tetradecane as a carbon source. This is the first report of a gram-negative bacterium which can desulfurize 4,6-dibutyl DBT and 4,6-dipentyl DBT. The desulfurized product of DBT produced by this strain was 2-hydroxybiphenyl, as in the case of other DBT-desulfurizing bacteria. S. subarctica T7b could desulfurize LGO and the sulfur content was decreased to 41% within 36 h.     

Role of Tannin-Binding Salivary Proteins and Tannase-Producing Bacteria in the Acclimation of the Japanese Wood Mouse to Acorn Tannins

We studied the defense mechanisms against the negative effects of tannins in acorns by using the Japanese wood mouse (Apodemus speciosus) and acorns of a Japanese deciduous oak Quercus crispula, which contain 9.9% tannins on a dry weight basis. For the experiment, we allocated 26 wood mice into two groups: acclimated (N = 12) and nonacclimated (N = 14). Mice in the nonacclimated group were fed only acorns for 10 d after 4 wk of receiving a tannin-free diet. In contrast, mice in the acclimated group received ca. 3 g acorns daily in addition to the tannin-free diet for the first 4 wk, then they were fed only acorns for 10 d. Body weight, food intake, and digestibility were monitored. In addition, the amount of salivary proline-rich proteins (PRPs) and abundance of tannase-producing bacteria (TPB) in the feces of mice were measured. Of the 14 mice in the nonacclimated group, 8 died, whereas only 1 of the 12 in the acclimated group died. During the first 5 d of feeding acorns only, mice in the nonacclimated group lost, on average, 17.5% of their body mass, while those in the acclimated group lost only 2.5%. Food intake, dry matter digestibility, and nitrogen digestibility were higher in the acclimated group than in the nonacclimated group. The results indicate that wood mice can mitigate the negative effects of tannins by acclimation. Path analysis revealed that increased secretion of PRPs and abundance of Lactobacillus type of TPB might explain the acclimation to tannins.     

Catalytic Performance of Metal Nanoparticles Supported by Ceramic Composite Produced by Partial Reduction of Solid Solution with Dopant

A composite with well-dispersed metal nanoparticles at a ceramic surface was produced by partial reduction of solid solution. It was found that a small amount of dopant, such as Al₂O₃, Cr₂O₃, or Sc₂O₃, accelerated the precipitation of the metal nanoparticles during the reduction. Catalytic performance of the composite for methanol reforming was evaluated. In the Ni-based catalysts, the dopant decreased the CO production by promoting a methanation reaction, while in the Co-based catalysts, the dopant did it by inducing a water–gas shift reaction. Co/MgO with Sc₂O₃ doping showed the most preferable reforming performance, high H₂ production, and CO₂ selectivity.