Preparation of mesoporous silica replica using ordered mesoporous carbon by vapor phase transport of silica source

A new vapor phase transport (VPT) technique to prepare an inverse silica replica of an ordered mesoporous carbon was developed. Tetraethyl orthosilicate (TEOS) was infiltrated in mesoporous carbon CMK-3 as the hard template at 180 °C for 48 h under an autogenous pressure in an autoclave in the presence of water. The samples obtained by removal of CMK-3 retained structural regularity of CMK-3 with little shrinkage of framework, which were characterized by SAXRD, N₂ adsorption, TG-DTA, and SEM. Influence of preparation temperature on the loading amount of silica was investigated. The multi-step replication process was monitored by characterizing the replicated materials as well as intermediate composites.     

One-Step Oxidation of Benzene to Phenol over Cu/Ti/HZSM-5 Catalysts

The gas-phase catalytic oxidation of benzene over copper supported on HZSM-5 added with titanium (Cu/Ti/HZSM-5) was carried out by using molecular oxygen as an oxidant. Phenol was effectively produced by the titanium addition to Cu/HZSM-5. The titanium addition to Cu/HZSM-5 induces the easy reduction of Cu²⁺ species to Cu⁺ species in the catalysts, and the produced Cu⁺ species seems to produce the phenol effectively.     

Hydrothermal Synthesis of Oriented Anatase Films Consisting of Columnar Aggregates and Their Wetting Properties

We hydrothermally synthesized anatase films on Ti substrates from transparent aqueous solutions of layered titanate colloids. The morphology and wetting properties of the films were examined. The films consisted of columnar aggregates grown on the Ti substrates, which resulted in high orientation. Randomly oriented films were obtained when alumina was used as a substrate, whereas the sol–gel precoating of a titanium oxide (TiO₂) layer on alumina substrates resulted in similar orientation as that of the films on Ti substrates. Thus, the presence of TiO₂ on the substrate surface plays an important role in the orientation of columnar aggregates. The columnar aggregates were similar in microstructure to the arms of a type of six-pointed star-like anatase aggregate synthesized hydrothermally from the same reaction solutions. They were composed of twins of tapered anatase nanocrystals, which provided a rough film surface. The film surface was highly hydrophilic and oleophilic due to the nanoscale roughness even when the film was not irradiated with UV light.     

40-Gb/s packet-selective photonic add/drop multiplexer based on optical-code label header processing

A packet-by-packet-selective photonic add/drop multiplexer, of the finest data granularity, is experimentally demonstrated at 40 Gb/s. An optical-code label, attached to the packet, enables determination, in the optical domain, of whether to drop, cut through, or add packets.     

Discharge characteristics of a new ACPDP structure using Thick‐Film Ceramic Sheet technology

Abstract— We have proposed a counterelectrode PDP structure in which the sustain and scan electrodes are embedded face to face in the ribs by applying Thick‐Film Ceramic Sheet technology. An advantage of the counterelectrode PDP is low discharge voltage, which does not depend on the dielectric thickness. A positive column is observed at a longer gap, and the luminous efficacy reaches 3.7 lm/W at Ne‐30%Xe at a 450‐μm discharge gap.     

Surface structure and visible light photocatalytic activity of titanium–calcium hydroxyapatite modified with Cr(III)

The synthetic titanium–calcium hydroxyapatite (Ti–CaHap) particles were treated with different concentrations of aqueous Cr(NO₃)₃·9H₂O solution and the materials obtained were characterized by a variety of conventional techniques. The crystal structure and particle morphology of Ti–CaHap were essentially not altered by treating with Cr(III) solution. With increasing the Cr(III) concentration, the amount of Cr(III) in the products was increased and that of Ca(II) was decreased. XPS results revealed that the surface state of Cr of Ti–CaHap was trivalent. These facts allow us to infer that the Cr(III) was doped by substitution of surface Ca(II) of Ti–CaHap. Besides, IR results proved that increasing the Cr(III) concentration developed the surface Cr–OH band while the surface Ti–OH and P–OH bands of Ti–CaHap vanished. This imply that the formation of surface P–O-Cr(OH)₂ and Ti–O–Cr(OH)₂ groups, resulting the Cr(OH)₃-like layer on the surface of Ti–CaHap particles. The Cr(III)-doped Ti–CaHap possessed the absorption peaks at 446 and 623 nm in vis range in addition to the UV absorption of charge transfer transition of O^2? → Ti⁴⁺. The vis absorption peaks developed on raising the Cr(III) concentration. The photocatalytic decomposition of acetaldehyde into CO₂ over Cr(III)-doped Ti–CaHap was detected under vis irradiation and the activity was lowered by the formation of Cr(OH)₃-like layer on the particle surface.     

Family M42 aminopeptidase from the syntrophic bacterium Symbiobacterium thermophilum: characterization using recombinant protein

The chromosomal DNA of the syntrophic thermophile Symbiobacterium thermophilum contains open reading frames of the genes encoding family M42 aminopeptidases, Pep1079, Pep1080, and Pep1081. To characterize these peptidases, the genes were cloned into Escherichia coli and overexpressed. Our experiments using the recombinant proteins confirmed that Pep1079, Pep1080, and Pep1081 are components of arginyl or lysinyl aminopeptidases that require Co2+ for enzymatic activity. Coexistence of Pep1079 and Pep1080 is necessary for expressing high peptidase activity. Pep1081 enhances the activity of Pep1079 and Pep1080.     

Clockless Stochastic Decoding of Low-Density Parity-Check Codes: Architecture and Simulation Model

This paper introduces clockless stochastic decoding for high-throughput low-density parity-check (LDPC) decoders. Stochastic computation provides ultra-low-complexity hardware using simple logic gates. Clockless decoding eliminates global clocking, which eases the worst-case timing restrictions of synchronous stochastic decoders. The lack of synchronization might use outdated bits to update outputs in computation nodes; however, it does not significantly affect output probabilities. A timing model of clockless-computation behaviours under a 90 nm CMOS technology is used to simulate the BER performance of the proposed decoding scheme. Based on our models, the proposed decoding scheme significantly reduces error floors due to the “lock-up” problem and achieves superior BER performance compared with conventional synchronous stochastic decoders. The timing model includes metastability to verify the affect on BER performance.     

A control method for the matrix converter based on virtual AC/DC/AC conversion using carrier comparison method

This paper proposes a novel control method based on the virtual AC/DC/AC conversion for the matrix converter. The virtual AC/DC/AC conversion method is a very simple strategy to control the input current and the output voltage for the matrix converter. There are two new topics proposed in this paper. First, this paper proposes the minimum switching loss modulation on the virtual rectifier. In our proposed modulation, only two arms switching in the virtual rectifier using DC link current control by the virtual inverter can obtain clean sinusoidal input current. Second, a novel lean controlled carrier modulation on the virtual inverter is proposed. The leans of the triangle carrier are controlled by the duty ratio of the rectifier side pulse. The lean controlled carrier reduces harmonic distortion of the input current by avoiding interference between the rectifier control and the inverter control. These new proposals are confirmed by simulation and experimental results. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 152(3): 65–73, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20144