Force‐based disturbance observer for dynamic force control and a position/force hybrid controller

In this paper, a force‐based disturbance observer (DOB) and a force control system using the DOB are proposed to obtain dynamic force control under disturbances. A DOB can reduce the effect of disturbances and modeling errors on robots. In a conventional DOB, an acceleration response is fed back to a reference, enabling highly precise position control. In other words, the effect of disturbances is decreased by emphasizing the effect of inertial forces. When a force controller is implemented, however, inertial forces are regarded as disturbances respect to a force response. Because inertial forces increase according to the acceleration, conventional DOBs are not suitable for dynamic force control. In the proposed DOB, a force response is fed back instead of an acceleration response. The effect of inertial forces is thus eliminated, thereby improving the tracking performance of force controllers. The proposed method's validity is verified analytically and experimentally. A position/force hybrid controller and a DOB for the controller are proposed as an extension of the proposed DOB. A bilateral controller is given as an example of the proposed hybrid controller, and its tracking performance is demonstrated experimentally. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Enhancement of the Catalytic Activity of a Dawson-type Heteropoly Acid Induced by the Loading on a Silica Support

The Friedel–Crafts alkylation, benzylation of anisole with benzyl alcohol, was carried out over heteropoly acids (HPAs) supported on SiO₂. A Dawson-type HPA, in which Nb atoms were partially substituted with W atoms, exhibited the highest activity among various kinds of HPAs. The catalyst was reusable in the reaction after the filtration and it kept high activity even after the washing with hot water when the catalyst was calcined at 743 K. In contrast, the unsupported catalyst was almost inactive after the thermal treatment. The change in the activity was in good agreement with the degree in the acid amount measured by NH₃-TPD. Unlike the Dawson-type heteropoly acid, the activity of the Keggin-H₃PW₁₂O₄₀/SiO₂ remarkably dropped through the repeated use for the reaction. Based on the structural analysis of Dawson-type HPAs, the partially decomposed HPA on the support of SiO₂ was ascribed to the active species.     

Nanostructured TiO2 photocatalyst and pump-probe spectroscopic study

Titanium dioxide (TiO₂), with its large band gap, has attracted much attention due to its excellent photocatalytic activity. TiO₂ ball-shaped nano-particles were deposited on silicon substrates by a thermal oxidation approach. With an increase in the annealing temperature the surface morphology and the structure of TiO₂ remained stable, exhibiting good heat stability; meanwhile, the hydrogen production rate also increased. The femtosecond pump-probe spectroscopic study showed that the lifetime of carriers of the samples as- deposited and post-annealed at different temperatures were longer than 20 ps.     

Time-resolved photoluminescence in Cu(In,Ga)Se2 thin films and solar cells

Room temperature time-resolved photoluminescence (TR-PL) measurements have been performed on Cu(In,Ga)Se₂ (CIGS) thin films and solar cells to clarify the recombination process of the photo-generated minority carrier. Both films and solar cells exhibited PL decay curves composed of the dominant fast (0.7-2 ns) and weak slow (3-10 ns) exponential decay curves. PL lifetime of the cell is longer than that of the thin films, indicating the longer minority carrier lifetime for the hetero-structures than in thin films. The increase of PL lifetime is consistent with the enhancement of the PL intensity and the elimination of defect-related PL as a result of the solar cell formation. These results are discussed in terms of the recombination process of carriers in films and hetero-structures. The relationship between the PL lifetime of the CIGS solar cells and the cell conversion efficiency is described.     

Synthesis and antibacterial activity of novel 7-(3-substituted-3 or 4-trifluoromethyl-1-pyrrolidinyl)-8-methoxyfluoroquinolones

The titled compounds were synthesized and evaluated for in vitro antibacterial activity. The (3R, 4S)-3-aminomethyl-4-trifluoromethyl derivative (S-34109) was confirmed to be optimal because of its superior activity against quinolone and methicillin-resistant Staphylococcus aureus and low side effect potential.     

Comparative data on the use of a cryosupernatant and fresh-frozen plasma in the therapy of a protracted infectious-septic syndrome of disseminated intravascular coagulation

AIM: To compare therapeutic effectiveness of cryosupernatant plasma fraction (CSP) and fresh-frozen plasma (FFP) in long-term infectious-septic DIC syndrome arising in acute abscess and gangrene of the lung. MATERIALS AND METHODS: 106 and 131 patients with infectious-septic DIC syndrome were treated with CSP and FFP, respectively. The results of the treatment were compared clinically and hemotopogically. RESULTS: Clinical response to both treatments was evident from positive changes in XIIa-dependent fibrinolysis, lowering of fibrinogen level and enhanced activity of antithrombin III. CSP treatment brought about a decrease in the number of thromboses, lethal cases, unfavorable outcomes. CONCLUSION: The cryosupernatant can be used instead of fresh-frozen plasma in combined treatment of long-standing infectious-septic DIC syndrome.     

Self‐Activated Vanadate Compounds Toward Realization of Rare‐Earth‐Free Full‐Color Phosphors

Rare‐earth‐free phosphors based on vanadate compounds were investigated, where the vanadates included chloride vanadates (M^II₂VO₄Cl), pyrovanadates (M^II₂V₂O₇), orthovanadates (M^II₃(VO₄)₂) with divalent cations M^II of Mg, Sr, Ba, and Zn, and oxofluorovanadates (A^IVOF₄) with an alkali metal A^I. A chloride pyrolysis method and a liquid phase precipitation method were proposed for preparing the chloride vanadates and pyro‐ and orthovanadates, respectively. These vanadate compounds showed self‐activated photoluminescence (PL) based on the VO₄ clusters against the ultraviolet (UV) light irradiation. The colors of PL covered almost the whole visible‐light region from blue to yellow as Sr₂VO₄Cl (deep blue), Ca₂VO₄Cl (sky blue), Ba₂V₂O₇ (green), Sr₂V₂O₇ (yellowish green), Zn₃(VO₄)₂ (yellow), and Mg₃(VO₄)₂ (yellow). A correlation was suggested from these compounds between the luminescent colors and the structural feature as the longer V–O distances in the VO₄ tetrahedra in the crystal structures led to the longer wavelength in PL. This seemed to be also applicable for the oxofluorovanadates A^IVOF₄ (A^I = K and Cs) which contain the VOF₄ polyhedra with one O^2? ion and four F^‐ ions as the ligands, as they exhibited the reddish PL.     

Production of L‐Lactic Acid from Spent Grain,a By‐Product of Beer Production

L‐lactic acid production from spent grain with immobilized lactic acid bacteria was investigated. Spent grains were liquefied by a steam explosion treatment to obtain liquefied sugar. When 1 kg of wet spent grain was treated under the 30 kg/cm²pressure for 1 min using a 5‐L steam explosion reactor, 60 g of total sugar was obtained from the liquefied spent grain. Furthermore, 1.3% (w/v) of glucose, 0.4% (w/v) of xylose, and 0.1% (w/v) of arabinose were produced when the liquefied spent grain was treated with glucoamylase, cellulase, and hemicellulase enzymes. When batch L‐lactic acid production was carried out by Lactobacillus rhamnosus NBRC14710, 19.0 g/L L‐lactic acid was produced from the Tween 80 liquefied spent grain after 5 days. Furthermore, during repeated batch production with immobilized Lactobacillus rhamnosus NBRC14710 from Tween 80 liquefied spent grain at 37°C, the productivity of L‐lactic acid was maintained at a 10 time higher level over a period of 40 days.     

Inhibition of Aldose Reductase Activity by Extracts from Hops

The inhibitory effect of beer on aldose reductase was investigated. Components present in beer strongly inhibited aldose reductase. Inhibition activity was observed primarily in the methanol‐soluble fraction of the beer and active components were identified to be of hop origin. Further, a component was identified as iso‐α‐acids, which are well known as main bitter components of beer. The inhibition rate of iso‐α‐acids was similar to quercetin, which is known to be a strong inhibitor of aldose reductase activity.