Synthesis of Metastable Tetragonal (t') Zirconia–Ceria Solid Solutions by the Polymerized Complex Method

Homogeneous metastable tetragonal ( t ') solid solutions of ZrO₂— x mol% CeO₂ ( x = 20 and 50) were successfully synthesized by the organic polymerized complex method. The citric acid-ethylene glycol solution containing Zr and Ce ions was polymerized at about 140°C and then heat-treated at about 350°C to obtain a precursor. The black precursor was heated at 450°C and then fired up to 1300° or 1590°C, resulting in the homogeneous solid solutions.     

Investigation of CH4 Reforming with CO2 on Meso-Porous Al2O3-Supported Ni Catalyst

Meso-porous Al₂O₃-supported Ni catalysts exhibited the highest activity, stability and excellent coke-resistance ability for CH₄ reforming with CO₂ among several oxide-supported Ni catalysts (meso-porous Al₂O₃ (Yas1-2, Yas3-8), -Al₂O₃, -Al₂O₃, SiO₂, MgO, La₂O₃, CeO₂ and ZrO₂). The properties of deposited carbons depended on the properties of the supports, and on the meso-porous Al₂O₃-supported Ni catalyst, only the intermediate carbon of the reforming reaction formed. XRD and H₂-TPR analysis found that mainly spinel NiAl₂O₄ formed in meso-porous Al₂O₃ and -Al₂O₃-supported catalysts, while only NiO was detected in -Al₂O₃, SiO₂, CeO₂, La₂O₃ and ZrO₂ supports. The strong interaction between Ni and meso-porous Al₂O₃ improved the dispersion of Ni, retarded its sintering and improved the activated adsorption of CO₂. The coking reaction via CH₄ temperature-programed decomposition indicated that meso-porous Al₂O₃-supported Ni catalysts were less active for carbon formation by CH₄ decomposition than Ni/-Al₂O₃ and Ni/-Al₂O₃.     

Influences of ZrO<Subscript>2</Subscript> nanoparticles on the microstructure and mechanical behavior of Ce-TZP/Al<Subscript>2</Subscript>O<Subscript>3</Subscript> nanocomposites

Influences of ZrO₂ nanoparticles on the mechanical properties and microstructure of hot-pressing Ce-TZP/Al₂O₃ ceramics were investigated. Meanwhile, t-ZrO₂ to m-ZrO₂ transformation toughening mechanism was investigated by X-ray diffractometry (XRD) method, and deflection of samples under applied stress were recorded too. The results show that when the percentage of ZrO₂ was 20%, the mechanical properties and microstructures of materials are optimum. Moreover, TEM observation show dislocation structures formation both in the Al₂O₃ and on the grain boundary. Because the dislocation agglomeration and fixation by ZrO₂ nanoparticles could deflect cracking or stop cracking development, a strengthening and toughening effect could be achieved.     

Determination of Precise Unit-Cell Parameters of the α-Tricalcium Phosphate Ca3(PO4)2 Through High-Resolution Synchrotron Powder Diffraction

Unit-cell parameters of the α-tricalcium phosphate [TCP; Ca₃(PO₄)₂] were investigated using high-resolution synchrotron powder diffraction and the Rietveld method. The diffraction experiment was conducted at 29°C at the BL-15XU experimental station of SPring-8, Japan. Precise unit-cell parameters of the α-TCP were obtained; a =12.87271 (9), b =27.28034(8), c =15.21275(12) Å, α=γ=90°, and β=126.2078(4)°. The calculated density of α-TCP (2.8677 g/cm³) is smaller than that of β-TCP, indicating the "looser" structure of α-TCP.     

Isolation of Solid Solution Phases in Size‐Controlled LixFePO4 at Room Temperature

State‐of‐the‐art LiFePO₄ technology has now opened the door for lithium ion batteries to take their place in large‐scale applications such as plug‐in hybrid vehicles. A high level of safety, significant cost reduction, and huge power generation are on the verge of being guaranteed for the most advanced energy storage system. The room‐temperature phase diagram is essential to understand the facile electrode reaction of Li_xFePO₄ (0 < x < 1), but it has not been fully understood. Here, intermediate solid solution phases close to x = 0 and x = 1 have been isolated at room temperature. Size‐dependent modification of the phase diagram, as well as the systematic variation of lattice parameters inside the solid‐solution compositional domain closely related to the electrochemical redox potential, are demonstrated. These experimental results reveal that the excess capacity that has been observed above and below the two‐phase equilibrium potential is largely due to the bulk solid solution, and thus support the size‐dependent miscibility gap model.     

Binding of organic anions by synthetic supramolecular metallopores with internal Mg2+-aspartate complexes

We report that cation-selective transmembrane pores formed by synthetic p-octiphenyl beta barrels with internal aspartate residues can be transformed into anion-permeable metallopores with internal Mg(2+)-aspartate complexes. These metallopores are shown to be useful for fluorimetric sensing of a broad variety of organic anions of biological relevance such as phytate, heparin, thiamine phosphates, and adenosine triphosphate. The negligible flippase activity measurable for Mg(2+)-free pores indicates that transmembrane p-octiphenyl beta barrels do not disturb the lipid bilayer suprastructure, in other words, they form barrel-stave rather than toroidal pores.     

Enantioseparation of atropisomeric 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate in capillary electrophoresis by using di- and oligosaccharides as chiral selectors: di- and oligosaccharide chiral selectors in capillary electrophoresis

Twelve different disaccharides and a series of noncyclic malto- and cello-oligosaccharides were used as chiral selectors in capillary electrophoresis (CE). Most saccharides resolved the enantiomers of atropisomeric 1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BDHP) depending on the type (alpha or beta) and position of the linkage between monosaccharides. The effect of chain length of malto- and cello-oligosaccharides on enantioseparation of BDHP was also investigated. The nature of cations in background electrolytes affected significantly the separation of BDHP enantiomers.     

A Novel KCaNi/α-Al2O3 Catalyst for CH4 Reforming with CO2

A potassium and calcium co-promoted nickel catalyst (KCaNi/-Al₂O₃) prepared by a direct impregnation method possessed a high activity, high stability and excellent coke resistance properties in CH₄ reforming with CO₂. XRD, XPS and H₂-TPR characterizations indicated that (i) Ca and K strengthened the interaction between Ni and -Al₂O₃ and promoted the formation of a unique NiAl₂O₄ phase on the surface of the catalyst and (ii) Ca and K increased the dispersion of Ni and retarded its sintering. Coking reactions (CH₄ temperature-programmed decomposition and O₂-TPO) disclosed that K reduced carbon formation via CH₄ decomposition.     

An extrapolative-interpolative prediction coding method for HDTVsignals

Techniques are introduced to solve two problems caused by the wide bandwidth of HDTV signals. One problem is that HDTV signals have more random noise than conventional TV signals, which causes coding efficiency degradation. The other is that very high sampling frequencies are required, which restricts the hardware implementation of the coding algorithm. To solve the first problem, it is proposed to use a spatio-temporal adaptive filter that can reduce random noise and improve coding efficiency. With regard to the second problem, an extrapolative and interpolative coding algorithm with adaptive intrafield/interframe prediction is presented. This algorithm eliminates the problem caused by the high sampling frequencies and provides efficient coding performance. A computer simulation is carried out to estimate the coding performance. Based on the simulation results, experimental coder hardware was implemented for 1125-line/60 Hz HDTV signals in order to evaluate real-time coding performance. The experimental results show that this coding method can provide good picture quality at around 90 or 135 Mb/s, and that HDTV digital transmission is very promising at the broadband ISDN H₄ rate