First-principles investigation on the segregation of Pd at LaFe1-xPdxO3-y surfaces

First-principles calculations were performed to investigate the effect of Pd concentration and oxygen vacancies on the stability of Pd at LaFeO₃ surfaces. We found a much stronger tendency of Pd to segregate by taking the aggregation of Pd at LaFe_1-xPd_xO_3-y surfaces into consideration, resulting in a pair of Pd-Pd around a vacancy. Moreover, we predicted that one oxygen-vacancy-containing FeO₂-terminated surfaces would be stable at high temperatures by comparing the stability of LaFe_1-xPd_xO_3-y surfaces, which further supports our previous conclusion that a Pd-containing perovskite catalyst should be calcined at 1,073 K or higher temperatures in air to enhance the segregation of Pd in the vicinity of surfaces to rapidly transform the Pd catalyst from oxidized to reduced states on the perovskite support.     

The effect of material difference and flange nominal size on the sealing performance of new gasketless flanges

This paper deals with a new seal system between flange joints without using a gasket. This gasketless flange includes a groove and an annular lip that is machined in one of the flange rings which when removed being in contact with the other flange to form a seal line when the flanges are assembled. In this study, firstly, fundamental dimensions are examined for unplasticized polyvinyl chloride (PVC-U JIS) to obtain the best sealing performance. Then, the effects of material difference and flange nominal size upon the sealing performance of the new gasketless flange are investigated for two types of materials, 0.25% carbon steel (S25C JIS) and PVC-U. It is found that the critical internal pressure at which leakage appears is mainly controlled by the maximum stress at the annular lip for each material even if the flange nominal sizes are different. The gasketless flange made by PVC-U shows the higher critical internal pressure compared with the case of S25C if the same clamping forces are applied. The effect of stress relaxation for PVC-U on the sealing performance is also considered. Then, it may be concluded that this PVC-U gasketless flange as well as S25C has good sealing performance.     

Holographic polymer-dispersed liquid crystal memory for optically reconfigurable gate array using subwavelength grating mask

Holographic polymer-dispersed liquid crystal (HPDLC) memory formed by a subwavelength grating (SWG) mask is presented for new optical information processing. The SWG structure in a photomask is formed on the SiO(2) plate using the anisotropic reactive ion etching technique. The configuration contexts for optically reconfigurable gate arrays (ORGAs) are stored in the HPDLC memory by polarization modulation property based on the form birefringence of the SWG plate. The configuration context pattern in the HPDLC memory is reconstructed to write it for the ORGAs under parallel programmability.     

A Gedunin-Type Limonoid, 7-Deacetoxy-7-Oxogedunin,from Andiroba (Carapa guianensis Aublet) Reduced Intracellular Triglyceride Content and Enhanced Autophagy in HepG2 Cells

The seed oil of Carapa guianensis Aublet (Andiroba) has been used in folk medicine for its insect-repelling, anti-inflammatory, and anti-malarial activities. This study aimed to examine the triglyceride (TG) reducing effects of C. guianensis-derived limonoids or other commercially available limonoids in human hepatoblastoma HepG2 cells and evaluate the expression of lipid metabolism or autophagy-related proteins by treatment with 7-deacetoxy-7-oxogedunin (DAOG; 1), a principal limonoid of C. guianensis. The gedunin-type limonoids, such as DAOG (% of control at 20 μM: 70.9 ± 0.9%), gedunin (2, 74.0 ± 1.1%), epoxyazadiradione (4, 73.4 ± 2.0%), 17β-hydroxyazadiradione (5, 79.9 ± 0.6%), 7-deacetoxy-7α-hydroxygedunin (6, 61.0 ± 1.2%), andirolide H (7, 87.4 ± 2.2%), and 6α-hydroxygedunin (8, 84.5 ± 1.1%), were observed to reduce the TG content at lower concentrations than berberine chloride (BBR, a positive control, 84.1 ± 0.3% at 30 μM) in HepG2 cells pretreated with high glucose and oleic acid. Andirobin-, obacunol-, nimbin-, and salannin-type limonoids showed no effect on the intracellular TG content in HepG2 cells. The TG-reducing effect of DAOG was attenuated by the concomitant use of compound C (dorsomorphin), an AMPK inhibitor. Further investigation on the detailed mechanism of action of DAOG at non-cytotoxic concentrations revealed that the expressions of autophagy-related proteins, LC3 and p62, were upregulated by treatment with DAOG. These findings suggested that gedunin-type limonoids from Andiroba could ameliorate fatty liver, and that the action of DAOG in particular is mediated by autophagy.     

Microwave atomic force microscopy imaging for nanometer-scale electrical property characterization

We introduce a new type of microscopy which is capable of investigating surface topography and electrical property of conductive and dielectric materials simultaneously on a nanometer scale. The microwave atomic force microscopy is a combination of the principles of the scanning probe microscope and the microwave-measurement technique. As a result, under the noncontact AFM working conditions, we successfully generated a microwave image of a 200-nm Au film coating on a glass wafer substrate with a spatial resolution of 120 nm and a measured voltage difference of 19.2 mV between the two materials.     

Determination of surface selection rule of surface plasmon resonance near-infrared spectroscopy by using a Langmuir-Blodgett film

Near-infrared (NIR) absorption spectra of a cadmium arachidate Langmuir-Blodgett (LB) film were measured by surface plasmon resonance near-infrared spectroscopy (SPR-NIRS) based on the Kretschmann configuration with a 18.8-nm gold film. An NIR spectrum enhanced severalfold was obtained as a top ridge of the SPR-NIR spectra measured at different incident angles by using the principle of absorption-sensitive SPR. In order to determine the surface selection rule of SPR-NIRS, the enhanced NIR absorption spectrum of the LB film was compared to an unenhanced one without the gold film and to a normal incidence transmission spectrum. Moreover, a pair of out-of-plane (OP) and in-plane (IP) spectra were obtained by multiangle infrared spectroscopy analysis from a series of oblique incidence transmission measurements in the NIR region. It became obvious that the salient feature of the enhanced NIR absorption spectrum, i.e., the top ridge of the SPR-NIR spectra is almost equivalent to that of the OP spectrum. On the other hand, the unenhanced spectrum showed IP modes. These experimental results were well explained by calculation of the mean-square electric field based on the Fresnel formula.     

烧结厂烧结废气能见度分析

烧结厂可见的烧结废气严重影响工厂周围景色。通过详细分析大分厂一号烧结机烧结废气的组分和粉尘,对可见烟气的形成机理进行了讨论。含有硫酸的烧结废气在冷却过程中形成的可见烟气的主要物质为空气中的雾气凝结物。硫酸具有促进雾气凝结和降低可见水雾汽化的作用,废气中的粉尘可作为雾气凝结的凝结核。在名古屋3号烧结机进行的测试验证了这种机理认识,通过将富含SOx的气体与烧结废气重新混合来观察具有长尾迹的可见烟气。总之,要使烧结废气不可见,需要有脱硫设备。     

Tiliroside, a glycosidic flavonoid, inhibits carbohydrate digestion and glucose absorption in the gastrointestinal tract

Scope Recent studies have reported that tiliroside, a glycosidic flavonoid, possesses anti‐diabetic activities. In the present study, we investigated the effects of tiliroside on carbohydrate digestion and absorption in the gastrointestinal tract. Methods and results This study showed that tiliroside inhibits pancreatic α‐amylase (IC₅₀ = 0.28 mM) in vitro. Tiliroside was found as a noncompetitive inhibitor of α‐amylase with K_i values of 84.2 μM. In male ICR mice, the increase in postprandial plasma glucose levels was significantly suppressed in the tiliroside‐administered group. Tiliroside treatment also suppressed hyperinsulinemia after starch administration. Tiliroside administration inhibited the increase of plasma glucose levels in an oral glucose tolerance test, but not in an intraperitoneal glucose tolerance test. In human intestinal Caco‐2 cells, the addition of tiliroside caused a significant dose‐dependent inhibition of glucose uptake. The inhibitory effects of both sodium‐dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) inhibitors (phlorizin and phloretin, respectively) on glucose uptake were significantly inhibited in the presence of tiliroside, suggesting that tiliroside inhibited glucose uptake mediated by both SGLT1 and GLUT2. Conclusion These findings indicate that the anti‐diabetic effects of tiliroside are at least partially mediated through inhibitory effects on carbohydrate digestion and glucose uptake in the gastrointestinal tract.     

An exploratory study of diesel soot oxidation with NO2 and O2 on supported metal oxide catalysts

A number of supported metal oxide catalysts were screened for their catalytic performance for the oxidation of carbon black (CB; a model diesel soot) using NO₂ as the main oxidant. It was found that contact between the carbon and catalyst was a key factor in determining the rate of oxidation by NO₂. Oxides with low melting points, such as Re₂O₇, MoO₃ and V₂O₅ showed higher activities than did Fe₃O₄ and Co₃O₄. The activities of MoO₃ and V₂O₅ on various supporting materials were also examined. MoO₃/SiO₂ was the most active catalyst among the supported MoO₃ examined, whereas, V₂O₅/MCM-41 showed the highest activity among the supported V₂O₅. Different performances of the supported MoO₃ catalysts were explained by the interaction of MoO₃ with the supports: a strong MoO₃/support interaction may result in a poor mobility of MoO₃ and a poor activity for oxidation of carbon by NO₂. The high activity of V₂O₅/MCM-41 was associated with its catalysis of the oxidation of SO₂ by NO₂ to form SO₃, which substantially promotes oxidation of carbon by NO₂. Addition of transition metal oxides or sulfates to supported MoO₃ and V₂O₅ was also investigated. Combining MoO₃ or V₂O₅ with CuO on SiO₂, adding VOSO₄ to MoO₃/SiO₂ or MoO₃/Al₂O₃ and adding TiOSO₄ or CuSO₄ to V₂O₅/Al₂O₃ improved the catalytic performance.     

Breakdown of YBCO thin films during current limiting and methods of improving current limiting performance

We performed fault current limiting tests using YBCO thin films and investigated the reasons for their breakdown during current limiting. There were two patterns of film breakdown. One occurred immediately after current limiting and the other occurred during current limiting. In film breakdown, the quench propagation speed showed almost no change with increasing energy consumption per unit time, but the energy consumption per unit area increased with increasing energy consumption per unit time. Therefore, local areas of the film reached the melting point and arcing occurred. It is therefore concluded that the performance of the films can be improved by decreasing the energy consumption per unit time. Connecting a parallel capacitor to the film in order to limit the energy consumption per unit time is proposed and tested as a measure to improve the current limiting performance of thin films. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 20–27, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20709