Dip-coating of TiO2 films using a sol derived from Ti(O-i-Pr)4-diethanolamine-H2O-i-PrOH system

Diethanolamine (DEA) can suppress the precipitation of oxides from the alcoholic titanium isopropoxide solution in its hydrolysis so that much water can be added to the Ti(O-i-Pr)₄-diethanolamine-i-propanol the solution to give a clear solution. Addition of excess water converted the solution to the gel. The conditions for the formation of the clear solution and gel are examined. Uniform transparent TiO₂ films can be prepared by dip-coating with the clear solution. The limit of the thickness of uniform films was 200 to 240 nm. Films thicker than 1 m can be prepared by repeating the coating cycle. These films were well densified. Diethanolamine has some positive effect on the densification of the TiO₂ crystals.     

Calculation of cohesive energy of Ti4O7

The cohesive energy of Ti₄O₇not be determined experimentally by a Born-Haber cycle analysis because the heat of formation of this compound, one of the energies associated with steps involved in the cycle, has not been obtained experimentally. Therefore, this paper reports the calculation of the cohesive energy of Ti₄O₇ based on the real structure observed at 120 K by X-ray diffraction. The cohesive energy consists of the Madelung energy calculated by Ewald's method, the repulsive energy, van der Waals's energy, the zero-point energy and the energy associated with bipolarons formed in Ti₄O₇ at temperatures below 150 K. The calculated value for the cohesive energy is –390.26 eV per Ti₄O₇ molecule. This value is found to be nearly equal to the upper limit of the cohesive energy of the Ti₄O₇ molecule which is approximately estimated by extrapolating the experimental results for the heats of formation of TiO₂ and Ti₃O₅ in Born-Haber cycle analyses.     

Oxidation of Chemically Vapor-Deposited Silicon Nitride in Dry Oxygen at 1923 to 2003 K

Oxidation of chemically vapor-deposited Si₃N₄ was studied in dry oxygen between 1923 and 2003 K under a total pressure of 0.1 MPa using a thermogravimetric technique. At 1923 to 1953 K, a parabolic rate mechanism prevailed for the oxidation reaction. From 1973 K, the oxidation reaction exhibited a mixed linear-parabolic rate mechanism. At 2003 K, on the other hand, the oxidation of Si₃N₄ showed a linear behavior. Both amorphous silica and cristobalite were identified as reaction products on the oxidized Si₃N₄ surface using X-ray diffraction analysis. The percentage of cristobalite in the surface oxide scale was determined from the X-ray diffraction pattern. It was found that, at 2003 K, only amorphous silica was formed. The parabolic rate constants (K _p) obtained from this study were close to those obtained in the literature.     

Purification and characterization of a cold-active protease from psychrotrophic Serratia marcescens AP3801

Protease activity was detected in the culture medium of Serratia marcescens AP3801 grown at 10°C, which was isolated from soil collected from the top of a mountain. The enzyme, designated as CP-58 protease, was purified to homogeneity from the culture broth by ion exchange and gel filtration chromatographies. The molecular mass of the protease was 58 kDa, and its isoelectric point was close to 6.0. Maximal activity toward azocasein was observed at 40°C and from pH 6.5 to 8.0. The activity was strongly inhibited by 1,10-phenanthroline, suggesting that the enzyme is a metalloprotease. The N-terminal amino acid sequence was Ser-Leu-Asn-Gly-Lys-Thr-Asn-Gly-Trp-Asp-Ser-Val-Asn-Asp-Leu-Leu-Asn-Tyr-His-Asn-Arg-Gly-Asn (or Asp)-Gly-Thr-Ile-Asn-Asn-Lys-Pro-Ser-Phe-Asp-Ile-Ala. A search through databases for sequence homology aligned CP-58 protease with metalloprotease. The result of the cleavage pattern of oxidized insulin B-chain suggests that CP-58 protease has a broader specificity than other proteases against the peptide substrate.     

Reduction of state space in reinforcement learning by sensor selection

Much research has been conducted on the application of reinforcement learning to robots. Learning time is a matter of concern in reinforcement learning. In reinforcement learning, information from sensors is projected on to a state space. A robot learns the correspondence between each state and action in state space and determines the best correspondence. When the state space is expanded according to the number of sensors, the number of correspondences learnt by the robot is increased. Therefore, learning the best correspondence becomes time consuming. In this study, we focus on the importance of sensors for a robot to perform a particular task. The sensors that are applicable to a task differ for different tasks. A robot does not need to use all installed sensors to perform a task. The state space should consist of only those sensors that are essential to a task. Using such a state space consisting of only important sensors, a robot can learn correspondences faster than in the case of a state space consisting of all installed sensors. Therefore, in this paper, we propose a relatively fast learning system in which a robot can autonomously select those sensors that are essential to a task and a state space for only such important sensors is constructed. We define the measure of importance of a sensor for a task. The measure is the coefficient of correlation between the value of each sensor and reward in reinforcement learning. A robot determines the importance of sensors based on this correlation. Consequently, the state space is reduced based on the importance of sensors. Thus, the robot can efficiently learn correspondences owing to the reduced state space. We confirm the effectiveness of our proposed system through a simulation.     

Reconstruction method of local density fluctuation for heavy ion beam probe measurements

Heavy ion beam probe (HIBP) is an excellent diagnostic to measure the density and potential fluctuations simultaneously in magnetically confined plasmas. However, it has been well known that the density fluctuation measured with the HIBP is not local but contains the fluctuations along the beam orbits. In this article, a method is proposed to evaluate local density fluctuation in the HIBP measurements by removing the well-known path integral effects. The reconstructed density fluctuation amplitude and power spectrum are shown, for example, by applying the proposed method on the density fluctuation measurement data obtained in a toroidal helical plasma, Compact Helical System.     

Characteristic transfer function matrix-based linear feedback control system analysis and synthesis

In this article, the concept of control system synthesis via a method using the characteristic transfer function matrix (CTFM), is explained. Then, the formal definition of CTFM and the associated concept of connectivity are presented. Next, CTFM-based control system analysis and synthesis are discussed, together with the derivation of the necessary and sufficient conditions for the realisation of a proper controller. A summary of the design procedure is presented and three design examples are introduced, in order to illustrate this procedure. Finally, the main conclusions to the work are presented.