Initial microstructure and retained austenite in 8 Mn steel controlled by cooling rate

The present work investigates the effect of the initial microstructure on phase transformation after intercritical annealing by measuring the amount of austenite, which was obtained by X-ray diffraction and saturation magnetisation. Pieces of 8?Mn steel were austenitised at 1100°C for 1?h followed by different cooling rates: water, air, and furnace. Samples of each piece were subsequently intercritically annealed from 600 to 800°C followed by air cooling. The microstructure was characterised using scanning electron microscopy and electron backscatter diffraction. Results show how changing the cooling rate affects the temperature of intercritical annealing at which the highest content of retained austenite was obtained.     

The study of the effect of external additives on the synthesis of fumed TiO2 with a high content of rutile structure by the novel natural dropping thermal treatment

The effect of external additives on the synthesis of fumed TiO₂ with a high rutile structure content was studied. The focus of this investigation was on the external additive species, agglomerates of the fumed TiO₂ before and after the thermal treatment. The transformation ratio from the anatase to rutile structure of the thermally-treated fumed TiO₂ was investigated as a function of the fumed TiO₂ agglomerate before the thermal treatment. Small agglomerated powders resulted in a decrease of transformation temperature. Two novel results were obtained in this investigation. One was a new fumed TiO₂ with a 100% rutile structure having an excellent dispersibility being successfully synthesized by the thermal treatment of AEROXIDE® TiO₂ P 25 with a small portion of AEROSIL® R 972. The other was the remarkable acceleration of the transformation from the anatase to rutile structure and grain growth/sintering of the thermally-treated fumed TiO₂ observed at a relatively low thermal treatment temperature by the oxidation reaction of calcium stearate as an external additive.     

Effect of a low-fat diet enriched with oleic acid on postprandial lipemia in patients with type 2 diabetes mellitus

The aim of the present study was to compare the effects of a low-fat diet enriched with oleic acid to those of a low-fat diet enriched with linoleic acid on fasting lipids, postprandial lipemia, and oxidative susceptibility of low-density lipoprotein (LDL) in patients with type 2 diabetes mellitus (DM). In a 3-wk randomized crossover study, eight patients with type 2 DM were given an experimental low-fat diet enriched with either oleic acid or linoleic acid. The oleic-acid-enriched diet contained 5, 15, and 5% energy from saturated, monounsaturated, and polyunsaturated fatty acids, and the linoleic-acid-enriched diet contained 5, 5, and 15% energy from saturated, monounsaturated, and polyunsaturated fatty acids, respectively. In addition to evaluating the fasting lipids and oxidative susceptibility of LDL, we evaluated postprandial lipemia using an oral fat load at the end of each 3-wk dietary phase. There were no significant differences in fasting lipid profile or lag time of LDL oxidation between the two experimental dietary phases. The average and maximal increments of remnant-like particle (RLP) cholesterol levels during oral fat load were significantly higher after the oleic-acid-enriched dietary phase than after the linoleic-acid-enriched dietary phase. The area under the curve of RLP cholesterol was also significantly larger after the oleicacid-enriched dietary phase than after the linoleic-acid-enriched dietary phase. These results suggest that the oleic-acidenriched diet was associated with increased formation of postprandial chylomicron remnants compared with the linoleicacid-enriched diet.     

A surface motor-driven planar motion stage integrated with an XYθZ surface encoder for precision positioning

This paper describes a surface motor-driven XY planar motion stage equipped with a newly developed XYθ_Z surface encoder for sub-micron positioning. The surface motor consists of four linear motors placed on the same surface, two pairs in the XY-axes. The magnetic array and the stator winding of the linear motor are mounted on the platen (the moving element) and the stage base, respectively. The platen can be moved in the X-direction by the X-linear motors, and in the Y-direction by the Y-linear motors. It can also be rotated about the Z-axis if the X- or Y-linear motors generate a moment about the Z-axis. The surface encoder consists of two two-dimensional angle sensors and an angle grid with two-dimensional sinusoidal waves on its surface. The angle grid is mounted on the platen of the stage which is levitated by air-bearings. The angle sensors and the air-bearing pads are fixed on the stage base so that the motion of the platen is not affected by the electronic cables and air hoses. The XY-positions and θ_Z rotation of the platen can be obtained from the angle sensor outputs with resolutions of approximately 20 nm and 0.2′′, respectively. The surface encoder is placed inside the stage so that the stage system is very compact in size. Experimental results indicate that precision positioning can be carried out independently in X, Y and θ_Z with resolutions of 200 nm and 1′′, respectively.     

Understanding the Structural Evolution and Redox Mechanism of a NaFeO2–NaCoO2 Solid Solution for Sodium‐Ion Batteries

Na‐ion batteries have become promising candidates for large‐scale energy‐storage systems because of the abundant Na resources and they have attracted considerable academic interest because of their unique behavior, such as their electrochemical activity for the Fe³⁺/Fe⁴⁺ redox couple. The high‐rate performance derived from the low Lewis‐acidity of the Na⁺ ions is another advantage of Na‐ion batteries and has been demonstrated in NaFe_1/2Co_1/2O₂ solutions. Here, a solid solution of NaFeO₂‐NaCoO₂ is synthesized and the mechanisms behind their excellent electrochemical performance are studied in comparison to those of their respective end‐members. The combined analysis of operando X‐ray diffraction, ex situ X‐ray absorption spectroscopy, and density functional theory (DFT) calculations for Na_{1– x} Fe_1/2Co_1/2O₂ reveals that the O3‐type phase transforms into a P3‐type phase coupled with Na⁺/vacancy ordering, which has not been observed in O3‐type NaFeO₂. The substitution of Co for Fe stabilizes the P3‐type phase formed by sodium extraction and could suppress the irreversible structural change that is usually observed in O3‐type NaFeO₂, resulting in a better cycle retention and higher rate performance. Although no ordering of the transition metal ions is seen in the neutron diffraction experiments, as supported by Monte‐Carlo simulations, the formation of a superlattice originating from the Na⁺/vacancy ordering is found by synchrotron X‐ray diffraction for Na_0.5Fe_1/2Co_1/2O₂, which may involve a potential step in the charge/discharge profiles.     

The effect of hydrogen evolution reaction on conductance quantization of Au, Ag, Cu nanocontacts

We have mechanically fabricated Au, Ag, and Cu nanocontacts in solution under electrochemical potential control. At the hydrogen evolution potential, fractional conductance peaks appeared near 0.5 G(0) (G(0) = 2e(2)/h) in the conductance histogram of Au and Cu. This fractional conductance peak was not observed in the conductance histogram of Ag. In the case of Au nanocontacts in 50?mM H(2)SO(4) solution, a 0.1 G(0) peak appeared in the conductance histogram, as well as the 0.5 G(0) peak. The origin of the fractional conductance peak and its metal dependence are discussed based on previously reported values of metal-hydrogen binding energy, which was estimated by the exchange current density for the hydrogen evolution reaction.     

Organic nanowire-templated fabrication of alumina nanotubes by atomic layer deposition

Alumina nanotubes were fabricated by a template method. Tris-(8-hydroxyquinoline) gallium (GaQ3) organic nanowires were used as a soft template for coating with alumina using an atomic layer deposition technique. The deposition was conducted at 25 degrees C by using trimethylaluminum and distilled water as the precursors of Al2O3. Amorphous alumina nanotubes were obtained after removing the GaQ3 by dissolving in toluene or by heat treatment at 350 degrees C. The amorphous nanotubes could be crystallized by heating at 900 degrees C for 1 h in vacuum.     

Electrochemically grown Pd nanoparticles used for synthesis of carbon nanotube by microwave plasma enhanced chemical vapor deposition

Pd nanoparticles of well-defined shapes with face centered cubic structure were grown electrochemically on silicon substrates with high degree of reproducibility. As direct application of these electrochemically grown Pd nanostructures they have been used as catalyst for the growth of multi wall carbon nanotube (MWCNT). It is observed that the MWCNTs are filled with a Pd based material during growth by microwave plasma enhanced chemical vapor deposition (MPECVD) technique. High-resolution transmission electron microscopy, used to study the material inside MWCNT suggests the formation of PdH0.649 or Pd2Si during the growth of carbon nanotube. Raman spectroscopy has been used to study the structure of the MPECVD grown carbon nanotubes.     

Recombinant human monoclonal Fab fragments against rotavirus from phage display combinatorial libraries

PURPOSE: To test the hypothesis that modification of release pattern of nonsteroidal anti-inflammatory drugs (NSAIDs) formulations shifts gastrointestinal (GI) toxicity of the drugs from the upper GI region to the distal intestine. METHODS: We assessed tiaprofenic acid (TA)-induced upper and lower increased GI permeability (a surrogate marker of toxicity) after administration of 20 mg and 40 mg/kg regular release (powder) and modified release formulations [sustained release (SR) beads and diethyl-beta-cyclodextrin (DCD):TA inclusion complex (INC)]. Urinary excretion of oral doses of GI permeability probes sucrose and 51Cr-EDTA was determined as measures of gastroduodenal and distal intestine, respectively. Pharmacokinetics of TA enantiomers were also studied following administration of a single 20 mg/kg dose of racemic TA as oral SR beads and iv solution. For powder and INC, previously reported pharmacokinetic data were used. RESULTS: Regular powder significantly increased the permeability at the gastroduodenal level. Modified-release formulations, on the other hand, did not cause damage in the gastroduodenum but produced significant increase in the permeability of the lower intestine. Consequently, to assess the pharmacokinetic-pharmacodynamic relationship, a new model was developed in which contribution of toxicity resulted from direct exposure to the drug was considered. CONCLUSIONS: Since the observed site of GI damage corresponds to the site of release and absorption of NSAID from the formulation, the possibility of a shift in the site of damage must be considered for the modified release formulations. A parallel evaluation of upper and lower GI toxicity is essential for a complete assessment of NSAID-induced GI damage.     

A study on the preparation of supported metal oxide catalysts using JRC-reference catalysts. I. Preparation of a molybdena–alumina catalyst. Part 4. Preparation parameters and impact index

The effects of the volume and pH of the impregnation solution and of the calcination conditions were examined on the physicochemical and catalytic properties of a 13 wt% MoO₃/Al₂O₃ extrudate catalyst. The Al₂O₃ support and drying procedures (static conditions without flowing air) were fixed in the preparations. In the present series of catalysts, the amount of crystalline MoO₃ was marginally small. It was found that the dispersion of Mo oxide species increased as the volume of the impregnation solution increased, gradually approaching a maximum value. The increase in pH (2–8) of the impregnation solution was found to reduce the dispersion of Mo oxide species. The Mo dispersion increased slightly for the impregnation catalysts as the calcination temperature increased (673–873 K), whereas it decreased for the equilibrium adsorption catalysts. The effects of the calcination atmosphere (with or without flowing air, or with flowing humid air) were very small on the dispersion of Mo oxide species under the present preparation conditions. On the other hand, the methanol oxidation activity of MoO₃/Al₂O₃ was sensitive to the preparation parameters examined here. It was demonstrated by means of EPMA and XPS that a considerable migration of Mo took place during the calcination.

In the present study on the preparation of a 13 wt% MoO₃/Al₂O₃ catalyst, an impact index is proposed to measure the magnitude of the effects of the respective parameter(s) on the physicochemical and catalytic properties. With the Mo dispersion, the effects of the preparation parameter decreased in the order, surface area of the support >> drying process > volume of the impregnation solution > pH, calcination temperature and atmosphere. The size of the impact index for the dispersion of Mo sulfide species is 70–75% of that for the Mo oxide species. The HDS activity of the catalyst was less affected by the preparation parameters than the Mo sulfide dispersion. The preparation parameters affected the segregation of Mo on the outer surface of extrudates in a decreasing order: drying process > volume of the impregnation solution > pH, calcination conditions. It was found that the oxidation of methanol was affected most intensely by the drying procedures. The volume of the impregnation solution, calcination conditions and pH of the impregnation solution also strongly affected the oxidation activity. The impact index suggests that the sensitivity to the preparation variables of the physicochemical and catalytic properties of MoO₃/Al₂O₃ decreases in the order, methanol oxidation activity > surface Mo segregation > Mo oxide dispersion > Mo sulfide dispersion > HDS activity.