Discriminative detection of volatile sulfur compound mixtures with a plasma-polymerized film-based sensor array installed in a humidity-control system

We demonstrated the discrimination of volatile sulfur compound mixtures with different mixing ratios by using an array of the plasma-polymerized film (PPF)-coated quartz crystal resonators. The PPF sensor array, which contains PPFs prepared from amino acids and synthetic polymers, exhibited different response patterns to mono or mixed volatile sulfur compounds (VSCs) (hydrogen sulfide and methanethiol) under a dry environment. The sensor array was installed in a desktop-size relative humidity controller. The relative humidity and temperature conditions of the sample flow to the sensor cell were equalized to those of the inner atmosphere of the sensor cell based on the concept of the two-separate-temperatures method. In this way, the baseline drift of PPF sensor response caused by the introduction of a highly humid sample was successfully suppressed. We compared the sensor array responses under the controlled humidity conditions. Presorption of water molecules by PPFs caused a decrease of sensor sensitivity, but the films still had the ability to discriminate sub-ppmv VSC mixtures having 6:1, 1:1, and 1:6 mixture ratios of hydrogen sulfide and methanethiol.     

Phospholipid requirement of alkylglycerol monooxygenase from rat liver microsomes

The alkylglycerol monooxygenase catalyzing the cleavage of the ether bond in alkylglycerol resides in rat liver microsomes. The enzyme preparation was freed of phospholipids by sodium deoxycholate treatment followed by gel filtration in the presence of deoxycholate. The removal of phospholipids markedly decreased the alkylglycerol monooxygenase activity. The activity of the delipidated enzyme, however, could be completely restored by the addition of phospholipid vesicles without detergent. When individual phospholipids were added, anionic phospholipids such as phosphatidylglycerol and diphosphatidyl-glycerol were the most effective. These findings, along with our previous observation of a similar effect of liposomes on the purified enzyme, indicate that the amphipathic nature of the protein is responsible for the lipid dependence of enzymatic activity.     

Interactions between large organic cations and cation exchange membranes

Interactions between cation exchange membranes and large organic cations have been studied; namely (1) adsorption and electrodialytic desorption of cationic surface active agents, and (2) change in transport properties of the membranes by adsorption.N-dodecyl pyridyl compounds, such as N-dodecyl pyridinium bromide (C₁₂-Py), N-dodecyl dipyridyl bromide (C₁₂-Dipy) and N-dodecyl tripyridyl bromide (C₁₂-Tripy) were used for the adsorption and electrodialytic desorption; and for the study on the change in transport properties of membranes, N-dodecyl pyridinium chloride, C₁₂-Py, C₁₂-Dipy, C₁₂-Tripy and hexadecyl trimethylammonium chloride were used. It was confirmed that the higher the molecular weight of the cation the longer the time required to reach adsorption equilibrium, and that the amount of adsorption exceeded the ion-exchange capacity of the membrane. After equilibrium was attained, electrodialytic desorption from the membranes was difficult.The adsorption or ion-exchange of large organic cations was effective to the permselectivity of the cation exchange membrane to the sodium ion in electrodialysis of a solution of sodium chloride and calcium chloride. The relationship between the permselectivity and the properties of the cations was examined.     

High refresh rate and low power consumption AMOLED panel using top‐gate n‐oxide and p‐LTPS TFTs

A pixel circuit and a gate driver on array for light‐emitting display are presented. By simultaneously utilizing top‐gate n‐type oxide and p‐type low‐temperature polycrystalline silicon (LTPS) thin‐film transistors (TFTs), the circuits provide high refresh rate and low power consumption. An active‐matrix LED (AMOLED) panel with proposed circuits is fabricated, and driving at various refresh rate ranging from 1 to 120 Hz could be achieved.     

Influence of surface roughness created by admixing smaller particles on improving discharge particle flowability of main particles

Particle flowability can be improved by admixing with particles smaller than the main particles. However, the mechanism by which this technique improves flowability is not yet fully understood. In this study, we focused on vibrating discharge particle flowability as one type of flowability and investigated the influence of the main particle roughness created by the adhesion of the admixed particles on improving the flowability. The diameters of the main and admixed particles (MPs and APs) were 41.4 or 60.8?μm and 8 or 104?nm, respectively. The main and admixed particles were mixed in various mass ratios, and the discharge particle flow rates of the mixed particles were measured. Scanning electron microscopy images were acquired from two different angles to determine the three-dimensional surface roughness using image analysis software. We then calculated the coating structure parameters from the obtained three-dimensional surface roughness. The observed trends for improving the vibrating discharge particle flowability were found to differ from those reported for compression particle flowability. Furthermore, the main particle roughness conditions that led to the greatest improvement involved the presence of several admixed particle agglomerations between the main particles.     

Mesoscale-structure control at anode/electrolyte interface in solid oxide fuel cell

To enhance the power density of a solid oxide fuel cell, a mesoscale-structure control of an electrode/electrolyte interface was proposed; here, the mesoscale means a size range of 10-100 μm, which is larger than the microscale of the electrode particles but smaller than the macroscale of the cell geometries. Therefore, the mesoscale structure does not only change the local thickness of the electrolyte and electrode but also enlarge the electrode/electrolyte interface area, and thus influence the cell performance. First, to find effective conditions for the mesoscale-structure control, a preliminary theoretical analysis in a conventional flat cell was performed focusing on the ratio of the ion-conducting resistance to the reaction resistance. In the light of this basic knowledge, as a second step, the effects of the mesoscale structure on an anode side of an electrolyte-supported cell were studied numerically and experimentally. A 2D numerical simulation based on an equivalent electrical circuit model and the dusty-gas model was carried out. As a result, the mesoscale-grooved structure was found to be effective for enhancement of the power generation, if the groove scale is sufficiently larger than that of the active reaction region of the electrode. Qualitatively similar results were obtained from the experiments using a segmented electrode with both flat and mesoscale-grooved surface in a button-type cell.     

Interaction of inorganic arsenic with biogenic manganese oxide produced by a Mn-oxidizing fungus, strain KR21-2

In batch culture experiments we examined oxidation of As(III) and adsorption of As(III/V) by biogenic manganese oxide formed by a manganese oxide-depositing fungus, strain KR21-2. We expected to gain insight into the applicability of Mn-depositing microorganisms for biological treatment of As-contaminated waters. In cultures containing Mn2+ and As(V), the solid Mn phase was rich in bound Mn2+ (molar ratio, approximately 30%) and showed a transiently high accumulation of As(V) during the early stage of manganese oxide formation. As manganese oxide formation progressed, a large proportion of adsorbed As(V) was subsequently released. The high proportion of bound Mn2+ may suppress a charge repulsion between As(V) and the manganese oxide surface, which has structural negative charges, promoting complex formation. In cultures containing Mn2+ and As(III), As(III) started to be oxidized to As(V) after manganese oxide formation was mostly completed. In suspensions of the biogenic manganese oxides with dissolved Mn2+, As(III) oxidation rates decreased with increasing dissolved Mn2+. These results indicate that biogenic manganese oxide with a high proportion of bound Mn2+ oxidizes As(III) less effectively than with a low proportion of bound Mn2+. Coexisting Zn2+, Ni2+, and Co2+ also showed similar effects to different extents. The present study demonstrates characteristic features of oxidation and adsorption of As by biogenic manganese oxides and suggests possibilities of developing a microbial treatment system for water contaminated with As that is suited to the actual situation of contamination.     

Development of a Thermal Buffering Device to Cope with Temperature Fluctuations for a Thermoelectric Power Generator

To stabilize the heat input to a thermoelectric generator (TEG) and protect it from large temperature fluctuations, a thermal buffering device (TBD) was fabricated and examined using a typical Bi-Te TEG module and a brand-new Mg₂Si TEG module. The TBD comprises two adjoining heat storage containers, each containing different alloys, which can be optimized for the temperature range of the TEG. The combination of two alloys in series diminishes the thermal fluctuations, stabilizing the heat input to the TEG module. This is achieved by having two metallic materials with large enthalpies of fusion that can be placed between the heat source and the TEG. The combination of the two alloys can be optimized for the temperature ranges of Bi-Te, Pb-Te, or Co-Sb. For the Bi-Te TEG, 15Al-85Zn and 30Sn-70Zn alloys were used for the heat source side and the TEG side, respectively. The corresponding alloys for the Mg₂Si TEG were 20Ni-80Al and 7Si-93Al. With the use of a TBD, the Bi-Te TEG exhibited no notable damage even in the rather high temperature range beyond ??573?K. For the Mg₂Si TEG, no operational damage of the Mg₂Si TEG module was observed even with a temperature of 1020?K.     

A hybrid input charge‐pump using micropower thermoelectric generators

For industrial wireless transmitters, a hybrid input charge‐pump utilizing thermoelectric energy from waste heat is proposed in this paper. Unlike conventional converters, the proposed capacitor‐based converter supplies energy to a wireless transmitter by using a thermoelectric power source in combination with a rechargeable battery source. By combining the battery voltage and the thermoelectric generator (TEG) voltage, the proposed converter achieves a wider input range than conventional converters. Consequently, the proposed converter will enable the development of not only an industrial wireless transmitter but also various clean energy applications. Through theoretical analyses, simulations, and experiments, the following results are shown: 1. Even if the voltage of the TEG is small, the proposed converter can provide the sufficient voltage by compensating the insufficient voltage of the TEG with the battery voltage. 2. The formulas obtained by the theoretical analyses are useful for designing the proposed converter because the theoretical results correspond well with the simulation results. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.