NMR study on reaction processes from aluminum chloride hydroxides to alpha alumina powders

Starting from gelatinous aluminum chloride hydroxide, the transformation process toward α-Al₂O₃ was examined using ²⁷Al NMR, both in the liquid and solid states, as a main analytical tool. By increasing the hydrolysis ratio (h, defined as [OH⁻]/[Al³⁺]) of the starting aqueous precursor up to h = 2.5, the transition temperature to the final product, α-Al₂O₃, decreased to as low as 500°C. In this case, the structural change from amorphous alumina to α-Al₂O₃ took place without intermediate transition Al₂O₃ phases. Examining the process of networking during the transition from aqueous sol–through the state of xerogel–to final anhydrous oxide by nuclear magnetic resonance (NMR) revealed the presence of highly polymeric species mainly ascribed to δ-[Al₂O₈Al₂₈(OH)₅₆(H₂O)₂₄]¹⁸⁺ (δ-Al₃₀). δ-Al₃₀ species were found in the solution phase and became predominant after drying. We conclude that the lower temperature synthesis of α-Al₂O₃ became possible due to preformation of polymerized AlO₆ construction units in the precursor, reducing the energy barrier for the nucleation of the final α-Al₂O₃ phase.     

Construction of Cellulose Binding Domain Fusion FMN-Dependent NADH-Azoreductase and Glucose 1-Dehydrogenase for the Development of Flow Injection Analysis with Fusion Enzymes Immobilized on Cellulose

The cellulose binding domain (CBD) of cellulosome-integrating protein A from Clostridium thermocellum NBRC 103400 was genetically fused to FMN-dependent NADH-azoreductase (AZR) and glucose 1-dehydrogenase (GDH) from Bacillus subtilis. The fusion enzymes, AZR-CBD and CBD-GDH, were expressed in Escherichia coli Rosetta-gami B (DE3). The enzymes were purified from cell-free extracts, and the specific activity of AZR-CBD was 15.1 U/mg and that of CBD-GDH was 22.6 U/mg. AZR-CBD and CBD-GDH bound strongly to 0.5 % swollen cellulose at approximately 95 and 98 % of the initial protein amounts, respectively. After immobilization onto the swollen cellulose, AZR-CBD and CBD-GDH retained their catalytic activity. Both enzymes bound weakly to 0.5 % microcrystalline cellulose, but the addition of a high concentration of microcrystalline cellulose (10 %) improved the binding rate of both enzymes. A reactor for flow injection analysis was filled with microcrystalline cellulose-immobilized AZR-CBD and CBD-GDH. This flow injection analysis system was successfully applied for the determination of glucose, and a linear calibration curve was observed in the range of approximately 0.16–2.5 mM glucose, with a correlation coefficient, r, of 0.998.     

A quality control method by ultrasonic vibration energy and diagnosis system at trimming process

To investigate a relation between vortex clusters and large-scale structures in the outer layer of wall turbulence, direct numerical simulations of turbulent channel flows have been conducted up toRe _τ = 1270. The vortex clusters in the outer layer consist coherent fine scale eddies (CFSEs) of which diameter and maximum azimuthal velocity are scaled by the Kolmogorov length and the Kolmogorov velocity. The CFSE clusters are inside the large-scale structure, which contributes to the streamwise velocity deficit The scale of those clusters tends to be enlarged with the increase of a distance from the wall. The CFSE clusters are composed of the relatively strong CFSEs, which play an important role in the production of the Reynolds shear stress and the dissipation rate of the turbulent kinetic energy. The most expected maximum azimuthal velocity of the CFSEs in these low-momentum regions of the outer layer is 30–70% fester compared with those of the CFSEs in unconditioned regions (i.e. all regions of the outer layer), while the most expected diameter of the CFSEs is not changed greatly.     

Mechanochemical syntheses of LiFeGe<Subscript>2</Subscript>O<Subscript>6</Subscript>-based nanocomposite and novel nanoglassy LiFeTi<Subscript>2</Subscript>O<Subscript>6</Subscript>

Two members of the pyroxene family, the germanate-type LiFeGe₂O₆ and the titanate-type LiFeTi₂O₆, are prepared for the first time via non-conventional one-step mechanosynthesis. The evolution of the as-prepared materials in the course of mechanosynthesis and their structural state on the long-range and local atomic scales are characterized by X-ray diffraction and ⁵⁷Fe Mössbauer spectroscopy, respectively. Both, the nanocrystalline nature of LiFeGe₂O₆ and the nanoglassy state of LiFeTi₂O₆ are revealed.     

Analyses of biped walking posture by dynamical-evaluating index

In this paper, biped walking posture and design are evaluated through dynamic reconfiguration manipulability shape index (DRMSI). DRMSI is the concept derived from dynamic manipulability and reconfiguration manipulability with remaining redundancy. DRMSI represents the ability of dynamical system of manipulators possessing shape changing acceleration in task space by normalized torque inputs, while the hand motion is assigned as the primary task. Besides, we use visual lifting approach to stabilize the walking and stop falling down. In this research, the primary task is to make the position of the head direct to the desired one as much as possible. And realizing the biped walking is the second task. This research indicates that proposed dynamical-evaluating index is effective in evaluating the biped walking motion and biped humanoid robot has the adjustable configuration to walk with higher flexibility. Flexibility represents the dynamical shape changeability of humanoid robot based on redundancy of the humanoid robot with the premise of the primary task given to keeping the head position high.     

The α–β Transformation in Silicon Nitride Single Crystals

Single crystals of α-Si₃N₄ were annealed at 2000°–2150°C. The β phase was detected after annealing at 2150°C only when the crystals were surrounded by MgO·3Al₂O₃ or Y₂O₃ powders. On the other hand, no evidence of the α–β transformation was found when the crystals were annealed without additives. The solution–precipitation mechanism was concluded to be the dominant factor in the α–β transformation of Si₃N₄.     

Synthesis and Sintering of Cerium(II) Monosulfide

Cerium monosulfide (CeS) powder was synthesized by the reduction of Ce₂S₃ powder with metallic Ce, which was obtained from ceria (CeO₂) powder using carbon disulfide (CS₂) gas. To obtain the maximum amount of CeS from a mixture of Ce₂S₃ and Ce, an excess amount of metallic Ce, a stoichiometric composition, was necessary in the synthesis at 1273 K for 10.8 ks. The preliminary sintering experiments also were performed using a synthetic CeS powder containing a small amount of Ce, Ce₂O₂S, and β-Ce₂S₃ as impurities. It was found that the oxygen content in the sintered compact decreases gradually as the sintering temperature increases, because of the removal of the impurities due to the evaporation of the volatile CeO. Single-phase CeS was formed by sintering at 2173 K. To evaluate the activation energy for densification of single-phase CeS, a CeS powder was prepared by milling an initial sintered compact and was used as an ingredient for hot-press experiments. Densification data during hot-press sintering were analyzed using a kinetic equation, showing that boundary diffusion is a rate-limiting process. The results suggest that this boundary diffusion model can explain well the densification data, with an apparent activation energy of 479 kJ·mol^-1.     

Effects of hexadecylphosphocholine on protein kinase C and TPA-induced differentiation of HL60 cells

Several structural analogs of alkylphosphocholine (APC) were studied for their effects on protein kinase C (PKC) and 12-O-tetradecanoylphorbol-13-acetate (TPA) elicited biochemical and cellular events in HL60 cells. Hexadecylphosphocholine (He-PC₂), the APC prototype, inhibited PKC competitively with respect to phosphatidylserine and noncompetitively with respect to CaCl₂, both with an apparent K_i of about 15 μM. Inhibition of PKC by He-PC₂ was selective, since cyclic AMP dependent protein kinase and Ca²⁺/calmodulin dependent protein kinase II were relatively unaffected. He-PC₂ inhibited TPA-induced depletion of PKC and TPA-stimulated phosphorylation of cellular proteins in HL60 cells. TPA-induced differentiation of HL60 cells was also inhibited by He-PC₂, and this inhibition was synergistic or additive to the effects of 1-(5-isoquinoline-sulfonyl)-2-methylpiperazine (H-7), a PKC inhibitor. The present findings are consistent with the hypothesis that inhibition of PKC might be related, in part, to the antineoplastic effect of He-PC₂ and ether lipid analogs such as ET-18-OCH₃ (1-octadecyl-2-methyl-glycero-3-phosphocholine).     

Control of biodegradability of poly(3‐hydroxybutyric acid) film with grafting acrylic acid and thermal remolding

Radiation‐induced graft polymerization of acrylic acid (AAc) on poly(3‐hydroxybutyric acid) (PHB) film was carried out and the resulting film was thermally‐remolded. The PHB films grafted with AAc (PHB‐g‐AAc) having a degree of grafting higher than 5% completely lost the enzymatic degradability. The enzymatic degradability of the grafted film was recovered by thermal remolding. The highest enzymatic degradation rate was observed at degree of grafting of 10% after thermal remolding. The PHB‐g‐AAc films and thermally‐remolded PHB‐g‐AAc films were characterized by contact angle and differential scanning calorimetry. The enzymatic degradability of PHB‐g‐AAc films was lost by the grafted AAc, which covered the surface of PHB film. The acceleration of enzymatic degradation in the remolded PHB‐g‐AAc films was mainly caused by decrease of crystallinity of PHB by dispread of grafted AAc during thermal remolding. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3856–3861, 2006     

A superelastic nanocrystalline Cu-Sn alloy thin film processed by electroplating

A nanocrystalline Cu-Sn alloy film was processed by electroplating, and the indentation tests and microstructural observation were conducted on the electroplated Cu-Sn alloy film. The indentation tests at room temperature showed that a large amount of strain was recovered on unloading for the electroplated Cu-Sn alloy film, in contract, such a large reversible strain was not found in an electroplated pure Cu film. Thus, the electroplated Cu-Sn alloy film exhibited superelastic behavior. The grain size of the Cu-Sn alloy film was 99 nm. In spite of the very small grain size, the austenite start and finish temperatures of the Cu-Sn alloy film were relatively high. This is suggested to be related to the presence of the α-Cu phase.