Photoluminescence and thermal stability of yellow-emitting Sr-α-SiAlON:Eu<Superscript>2+</Superscript> phosphor

Novel α-SiAlON:Eu²⁺-based yellow oxynitride phosphors with the formula Sr_0.375−x Eu _x ²⁺Si_12−m−n Al _m+n O _n N_16−n (m = 0.75, n = x = 0.004–0.04) have been prepared by firing the powder mixture of SrSi₂, α-Si₃N₄, AlN, and Eu₂O₃ at 2,000 °C for 2 h under 1 MPa nitrogen atmosphere. The luminescence properties, the dependence of the activator concentration of Eu²⁺ and the thermal stability of Sr-α-SiAlON:Eu²⁺ phosphor have been investigated in comparison with Ca-α-SiAlON:Eu²⁺ phosphor. Similar to Ca-α-SiAlON:Eu²⁺ phosphor, Sr-α-SiAlON:Eu²⁺ phosphor has the excitation wavelength ranging from the ultraviolet region to 500 nm, and exhibit intense yellow light. The strongest luminescence was achieved at about x = 0.02 with the emission peak at 578 nm, slightly shorter than that of Ca-α-SiAlON:Eu²⁺ phosphor at 581 nm. Temperature-dependent emission intensity of Sr-α-SiAlON:Eu²⁺ phosphor is comparable to that of Ca-α-SiAlON:Eu²⁺ phosphor. The results suggest that the different position of the emission peak for Sr- and Ca-α-SiAlON:Eu²⁺ depends on the composition and the Stokes shift, and the thermal stability is nearly independent of Sr and Ca or fixed by the network of (Si, Al)–(O, N) in α-SiAlON at the same Eu²⁺ concentration.     

D-allose protects against endotoxemic acute renal injury

D-allose is a monosaccharide. We previously reported that D-allose attenuated renal injury by inhibiting the activation of neutrophils after renal ischemia/reperfusion. Lipopolysaccharide (LPS) triggers sepsis syndrome by activating monocytes to produce proinflammatory cytokines, including tumor necrosis factor (TNF)-alpha, which potently stimulates the activation of neutrophils. This study was undertaken to examine the effects of D-allose on renal injury in the systemic inflammatory response induced by LPS administration, with emphasis on systemic TNF-alpha and the activation of neutrophils in the rat kidney. Serum and renal TNF-alpha, renal cytokine-induced neutrophil chemoattractant (CINC)-1, and myeloperoxidase (MPO) concentrations, and renal function after LPS administration were evaluated. D-allose (400 mg/kg body weight) inhibited LPS-induced increases in serum and renal TNF-alpha concentrations and renal CINC-1 and MPO concentrations after LPS administration, as well as the subsequent neutrophil-mediated renal injury. These findings may have important implications in understanding the biologic functions of D-allose. D-allose may prove useful in protecting against acute renal injury in systemic inflammatory responses to LPS.     

A method of fault diagnosis in adaptive control systems by using fuzzy inference

An on-line fault diagnosis scheme for adaptive controlled systems designed by a self-tuning approach is proposed. A physical parameter change in the controlled system can effectively be detected by using Kullback Discrimination Information (KDI) as an index for model discrimination. In the adaptive controlled system, parameter changes may occur under the normal operation, as well as under a failed situation. In order to decide whether the detected system parameter change really means a fault occurrence or not, a fuzzy inference approach to fault diagnosis is considered. Some appropriate membership functions which describe fuzzy events of the fault are constructed to implement the fuzzy inference. In this way, useful knowledge about fault modes obtained from, e.g., experts, can be introduced into the model-based diagnosis technique. Simulation studies on a second order damped oscillator have been carried out to demonstrate the effectiveness of the method.     

High-power piezoelectric characteristics of textured bismuth layer structured ferroelectric ceramics

Abstract-The high-power piezoelectric characteristics in h001i oriented ceramics of bismuth layer structured ferroelectrics (BLSF), SrBi(2)Nb(2)O(9) (SBN), (Bi,La)(4)Ti(3)O(12) (BLT), and CaBi(4)Ti(4)O(15) (CBT), were studied by a constant voltage driving method. These textured ceramics were fabricated by a templated grain growth (TGG) method, and their Lotgering factors were 95%, 97%, and 99%, respectively. The vibration velocities of the longitudinal mode (33-mode) increased proportionally to an applied electric field up to 2.5 m/s in these textured BLSF ceramics, although, the vibration velocity of the 33-mode was saturated at more than 1.0 m/s in the Pb(Mn,Nb)O(3)-PZT ceramics. The resonant frequencies were constant up to the vibration velocity of 2.5 m/s in the SBN and CBT textured ceramics; however, the resonant frequency decreased with increasing over the vibration velocity of 1.5 m/s in the BLT textured ceramics. The dissipation power density of the BLT was almost the same as that of the Pb(Mn,Nb)O(3)-PZT ceramics. However, the dissipation power densities of the SBN and CBT were lower than those of the BLT and Pb(Mn,Nb)O(3)-PZT ceramics. The textured SBN and CBT ceramics are good candidates for high-power piezoelectric applications.     

Numerical simulation of blow molding—prediction of parison diameter and thickness distributions in the parison formation process

In our previous study, we calculated the time course of parison length in the parison formation stage, but it could predict only the parison area swell. The next target in our study is to calculate the parison diameter and thickness swell. Annular extrudate swell simulation is necessary for the understanding of various kinds of swelling ratios in blow molding. We have examined three kinds of swells (outer diameter, thickness, and area swells) obtained from simulation results of annular extrudate swell, using the Giesekus model, and have developed a method of predicting parison outer diameter and thickness swell values. The predicted values of parison outer diameters are discussed in comparison with experimental data, and reasonable results are obtained by the proposed method. This prediction method could also be applied to the parison formation process using a parison controller. As a result, it is possible to predict approximately the whole process of parison formation by numerical simulation.     

Efficient Conversion of Glycerol into High Value-Added Chemicals by Partial Oxidation

Glycerol can be effectively converted to glyceric acid, a high value-added pharmaceutical raw material, through its partial oxidation over an Au/Al₂O₃ catalyst under strongly basic conditions. The factors important for the highly selective production of glyceric acid were investigated experimentally. It was clarified that NaOH was involved in the glycerol activation step to a glycerol alkoxide intermediate (2, 3-dihydroxypropoxide) in the liquid phase, then glyceric acid was formed by OOH species derived from O₂ on an Au catalyst in the partial oxidation step. We have newly discovered the concerted effect of NaOH and O₂ in different reaction steps.