Synthesis of TiO2/CdS nanocomposite via TiO2 coating on CdS nanoparticles by compartmentalized hydrolysis of Ti alkoxide

Hydrolysis of Ti alkoxide in the presence of inverse micelles containing CdS nanoparticles in their hydrophilic interior results in formation of TiO₂/CdS nanocomposites in which the CdS nanoparticles are embedded in a TiO₂ matrix with a thickness of 10 nm at the surface of the particles. The primary hydroxyl groups introduced by 2-mercaptoethanol as a capping agent used for preparation of the CdS nanoparticles are considered to play an important role for successful adhesion and growth of the TiO₂ layer on the CdS surfaces. TEM observation strongly supports formation of semiconductor-in-semiconductor heteronanostructure by compartmentalized hydrolysis of Ti alkoxide within the inverse micelles in which the surface-capped CdS nanoparticles coexist.     

Expression of a gene encoding chitinase (pCA 8 ORF) from Aeromonas sp. no. 10S-24 in Escherichia coli and enzyme characterization

A gene encoding chitinase from Aeromonas sp. no. 10S-24 was expressed using pTrc99A in Escherichia coli JM 105 which yielded a 5-fold higher activity than when pUC19 was used. Three different truncated enzymes (SA-1, SA-2 and SA-3) were obtained after purification. Their isoelectric points were 7.0, 6.9, and 6.7, respectively. The enzymes showed two optimum pHs, 4.0 and 7.0, when incubated with ethylene glycol chitin as the substrate, and were stable over a wide pH range (3.0-9.0). The optimum temperature was 60 degrees C and the enzymes were stable up to 50 degrees C. The chitinases exhibited wide substrate specificities for chitin-related compounds.     

Piezoelectric Vibration-Type Tactile Sensor Using Elasticity and Viscosity Change of Structure

We propose a new tactile sensor utilizing piezoelectric vibration. This tactile sensor has a high sensitivity, wide measurement range, pressure resistance, flexibility, and self-sensing function. This tactile sensor comprises two piezoelectric materials. One is used for the vibration of the sensor element and the other is used for the measurement of the change in mechanical impedance induced by an external force. We achieved the wide measurement range by implementing two ideas. One was to apply the external force to the sensor element through an elastic body and the other was to use two or more modes of vibration. Moreover, for the elastic body, it is preferable to use a material whose elasticity and viscosity are easily changed by an external force, such as a gel. In this study, first, this tactile sensor was analyzed, and then its characteristics were derived. The analytical results qualitatively corresponded to the experimental results. Next, a prototype tactile sensor was fabricated and evaluated. The evaluation results showed that this tactile sensor can measure a pressure of 2.5 Pa or less and a pressure of 10 kPa or more and its pressure resistance is 1 MPa or more.     

Selection of manipulator system for multiple-goal task by evaluating task completion time and cost with computational time constraints

The focus of this study is on the problem of manipulator system selection for a multiple-goal task by evaluating task completion time and cost with computational time constraints. An approach integrating system selection, structural configuration design, layout design, motion planning, and relative cost calculation is proposed to solve this problem within a reasonable computational time. In the proposed approach, multiple-objective particle swarm optimization (MOPSO) is utilized to search for the appropriate manipulator system with appropriate structural configuration from a set of candidate systems. Particle swarm optimization (PSO) and the nearest neighborhood algorithm are employed in layout design and motion planning due to their high convergence speed. Three methods involving a random search algorithm are compared to the proposed approach through a simulation. The simulation is done with a set of tasks and the result shows the effectiveness of the proposed approach.     

BWR core internals replacement

The core shroud and other internal component (core internals) replacements were carried out at Fukushima-Daiichi unit number three of Tokyo Electric Power Company (TEPCO) in Japan. The project is the first experience of replacement procedures that have been developed for welded core shrouds and jet pumps. The outline and experience of the project are discussed in this paper.     

The functional implications of the dimerization of the catalytic subunits of the mammalian brain platelet-activating factor acetylhydrolase (Ib)

The mammalian brain contains significant amounts of the cytosolicisoform Ib of the platelet-activating factor acetylhydrolase(PAF-AH), a unique type of PLA2. This oligomeric protein complexcontains three types of subunits: two homologous (63% identity)26 kDa catalytic subunits (     

1.8-V 800-Mb/s/pin DDR2 and 2.5-V 400-Mb/s/pin DDR1 compatibly designed 1Gb SDRAM with dual-clock input-latch scheme and hybrid multi-oxide output buffer

This paper describes three circuit techniques for a DDR1/DDR2-compatible chip architecture designed for both high-speed and high-density DRAMs: 1) a dual-clock input-latch scheme, which reduces the excessive timing margin for random input commands by using a pair of latch circuits controlled by dual-phase one-shot clock signals, achieves a 0.9-ns reduction in cycle time from 3.05 to 2.15 ns; 2) a hybrid multi-oxide output buffer reduces the area penalty of the output buffer caused by compatible chip design from 1.35% to 0.3%; and 3) a quasi-shielded distributed data transfer scheme enables a 2.6-ns reduction in access time to 10.25 ns in both 2-b and 4-b prefetch operations. By using these techniques, we developed a 175.3-mm/sup 2/ 1-Gb SDRAM that operates as an 800-Mb/s/pin DDR2 or 400-Mb/s/pin DDR1.     

Synthesis and Thermal Characterization of Novel Poly(tetramethylsilanthrylenesiloxane) and Poly(tetramethylsilphenanthrylenesiloxane) Derivatives

Summary Novel poly(tetramethylsilarylenesiloxane) derivatives, i.e. poly(tetramethyl-2,6-silanthrylenesiloxane) (P1), poly(tetramethyl-9,10-silanthrylenesiloxane) (P2), and poly(tetramethyl-1,8-silphenanthrylenesiloxane) (P3), were synthesized by polycondensation of novel disilanol monomers, i.e. 2,6-bis(dimethylhydroxysilyl)-anthracene (M1), 9,10-bis(dimethylhydroxysilyl)anthracene (M2), and 1,8-bis(dimethylhydroxysilyl)phenanthrene (M3), respectively. P1 and P3 were soluble in common organic solvents, such as benzene, toluene, chloroform, dichloromethane, tetrahydrofuran, etc. whereas P2 was almost insoluble in common organic solvents. It was revealed that P1 and P3 were amorphous and that P2 exhibited the crystallinity, as deduced from differential scanning calorimetry (DSC) and X-ray diffraction measurements. The glass transition temperatures (T_g’s) of P1 (118 °C) and P3 (100 °C) were much higher than that of poly(tetramethyl-1,4-silphenylenesiloxane). The temperature at 5% weight loss (T_d5) of P3 was 500 °C, which was higher than those of P1 and P2, and comparable to that of poly(tetramethyl-1,4-silphenylenesiloxane). It would be speculated that the thermostability of the series of poly(tetramethyl-silarylenesiloxane) derivatives is dependent on the stability of arylene moieties incorporated.