Using data compression for multidimensional distribution analysis [molecular biology]

A new method for multi-dimensional distribution analysis using a data compression technique applied to the knowledge-based mean-force potentials between residues for the analysis of protein sequence-structure compatibility performs much better than that of conventional 1D distance-based potentials derived from binned distributions.     

Anodically deposited manganese-molybdenum oxide anodes with high selectivity for evolving oxygen in electrolysis of seawater

Manganese-molybdenum oxide electrodes were prepared by anodic deposition on an IrO2-coated titanium substrate at a constant current density of 600Am–2 from baths containing 0.2M MnSO4 and 0–0.1M Na2MoO4 at 90C and pH 0.5. These electrodes were characterised for oxygen evolution in the electrolysis at 1,000Am–2 in 0.5M NaCl solution at 30C and pH 8 or 12. The most active and stable oxygen evolving anode exhibited 100% efficiency for oxygen evolution, and an efficiency of 98.5% for over 1,500 h at pH 12 and of 96.5% for over 2,800 h at pH 8 of continuous electrolysis. X-ray diffraction measurement and XPS analysis indicated that the deposits consist of a nanocrystalline single -MnO2 type phase, and manganese and molybdenum in the deposits are in the Mn4+ and Mo6+ states. The electrochemical studies showed that the manganese-molybdenum oxide electrodes drastically reduced the electrocatalytic activity for chlorine evolution to the undetectable level, resulting in 100% efficiency for oxygen evolution, although the addition of molybdenum slightly increased the oxygen overpotential.     

Catalytic activity of physically-mixed nickel compounds on the CO2 gasification of phenol-formaldehyde resin char

In order to account for the various activities of different nickel compounds in low temperature catalytic gasification of carbon the reducibility of individual nickel compounds in carbon dioxide to metallic was studied by thermogravimetry and the behaviour of mixture of nickel salts with a phenol-nickel formaldehyde resin char was investigated by temperature-programmed X-ray diffraction analysis. A correlation was found between the order of reducibility of the nickel salts and their order of activity in catalytic gasification. Low temperature gasification up to 98 wt% was demonstrated for char mixed with nickel acetate (up to 9/10 wt% Ni), which suggests that there may be good prospects for finding a method of complete gasification with nickel.     

Heterogeneous network polymers. IV. Dynamic mechanical properties—composition—phase structure relationships

Heterogeneous network polymers were prepared from poly(D -glutamic acid) (PGA) and poly(oxyethylene glycol) (PEG). The content of PGA was systematically varied: 30%, 40%, 50%, 60%, 65%, and 70% by weight. The molecular weights of the crosslinking PEG were 300, 600, 900, and 1800. The plots of the dynamic mechanical tan δ peak temperatures, the PGA interhelical distances (x-rays) and the densities against PGA contents showed a distinct break between 50% and 60%. The photographs under polarizing microscope also indicated an occurrence of phase inversion in the above content region. PGA containing small amounts of PEG and PEG containing small amounts of PGA were found to constitute the continuous phases, respectively, above and below the phase inversion region, while a well-mixed phase is always the dispersed phase. The glass transition was ascribed to the micro-Brownian motions of PGA, PEG, and PEG above and below the phase inversion region, respectively.     

High‐frequency drive of high‐Xe‐content PDPs for high efficiency and low‐voltage performance

Abstract— It has been well known that the luminous efficiency of PDPs can be improved by increasing the Xe content in the panel. For instance, the efficiency is improved by a factor 1.7 when the Xe content is increased from 3.5% to 30%. The sustain pulse voltage, however, increases from 180 to 230 V by a factor 1.3. It was found that the increase in the sustain pulse voltage can be suppressed by increasing the sustain pulse frequency. The high‐frequency operation further increases the luminous efficiency. If the Xe content is increased from 3.5% to 30% and the drive pulse frequency is increased from 147 to 313 kHz, the luminous efficiency becomes 2.7 times higher and the luminance 4.5 times higher. Furthermore, the increase in the sustain pulse voltage is suppressed 1.1 times, from 180 to 200 V. A mechanism of attaining high efficiency and low‐voltage performance can be considered as follows. A train of pulses is applied during a sustain period. As the sustain pulse frequency is increased, the pulse repetition rate becomes faster and a percentage of the space charge created by the previous pulse remains until the following pulse is applied. Due to the priming effect of these space charge, the discharge current build‐up becomes faster, the width of the discharge current becomes narrower, ion‐heating loss is reduced, and the effective electron temperature is optimized so that Xe atoms are excited more efficiently. The intensity of Xe 147‐nm radiation, dominant in low‐pressure Xe dis‐charges, saturates with respect to electron density due to plasma saturation. This determines the high end of the sustain pulse frequency.     

Mechanically Controlled Quantum Contact With On-Chip MEMS Actuator

We report fabrication and characterization of a mechanically controlled quantum point contact with on-chip electrostatic actuators. Two metallic tips separated with a nano gap are integrated with a micro mechanism, which can be actuated by applied voltage. The electrostatic actuation of the micro mechanism allows the control of separation gap at nanometer level. The gap variation at nanometer level is calibrated with the devices operated in transmission electron microscope. Furthermore, performance of the device is demonstrated by measuring conductance quantization while separating the tips in contact as well as electrical measurements by using tips coated with self assembled monolayers (1-4 benzene dithiol) and conjugated Ru complex     

Photocatalytic activity of gallium nitride for producing hydrogen from water under light irradiation

Photocatalytic activity of powdered GaN for decomposing water into hydrogen under light irradiation was investigated. It was found that GaN has activity for producing hydrogen from water containing electron donors (Na₂S-Na₂SO₃, CH₃OH) without a loading of a noble metal; the obtained H₂ yield was ca. 150 μmol for a 200 h-Xe lamp (300 W) irradiation. The activity was increased by adding NaOH in the reaction solution due to the photo-etching of GaN by NaOH and concomitant removal of the native oxide from the surface, as confirmed by XPS, XRD, and PL measurements. The band energy scheme for GaN suggests that the conduction band edge of GaN is positioned at 0.5 V higher than the redox potential of H⁺/H₂. This large energy difference (overpotential) makes the photocatalytic H₂ evolution over GaN from water possible.