Direct Physical Imaging and Chemical Probing of LiFePO4 for Lithium‐Ion Batteries

The control of unexpectedly rapid Li intercalation reactions without structural instability in olivine‐type LiFePO₄ nanocrystals is one of the notable scientific advances and new findings attained in materials physics and chemistry during the past decade. A variety of scientific studies and technological investigations have been carried out with LiFePO₄ to elucidate the origins of many peculiar physical aspects as well as to develop more effective synthetic processing techniques for better electrochemical performances. Among the several features of LiFePO₄ that have attracted much interest, in this article we address four important issues—regarding doping of aliovalent cations, distribution of Fe‐rich secondary metallic phases, nanoparticle formation during crystallization, and antisite Li/Fe partitioning—by means of straightforward atomic‐scale imaging and chemical probing. The direct observations in the present study provide significant insight into alternative efficient approaches to obtain conductive LiFePO₄ nanocrystals with controlled defect structures.     

Electrolyte effect on the catalytic performance of Ni-based catalysts for direct internal reforming molten carbonate fuel cell

An active and tolerant Ni-based catalyst for methane steam reforming in direct internal reforming molten carbonate fuel cells (DIR-MCFCs) was developed. Deactivation of reforming catalysts by alkali metals from the electrolyte composed of Li₂CO₃ and K₂CO₃ is one of the major obstacles to be overcome in commercialization of DIR-MCFCs. Newly developed Ni/MgSiO₃ and Ni/Mg₂SiO₄ reforming catalysts show activities of ca. 80% methane conversion. Subsequent to electrolyte addition to the catalyst, however, the activity of Ni/Mg₂SiO₄ decreases to ca. 50% of its initial value, whereas Ni/MgSiO₃ catalyst retains its initial activity. Results obtained from temperature-programmed reduction and X-ray photoelectron spectroscopy identify unreduced Ni³⁺ as a decisive factor in keeping catalytic activity from the electrolyte.     

Enhanced ionic conductivity and phase meta-stability of nano-sized thin film yttria-doped zirconia (YDZ)

Yttria-doped zirconia (YDZ) thin films with nanometric sized grains were prepared by reactive RF sputtering and their oxygen ion conductivities were systematically measured as a function of yttria doping with levels in the range 0.5–9.1 mol.% Y₂O₃. Enhanced oxygen ion conductivities, as derived from impedance spectra, were observed when compared with values reported for bulk YSZ. Furthermore, the peak conductivity for the YDZ films was observed to occur at considerably reduced yttria levels, i.e., at 6.5 mol.% Y₂O₃ (for T > ～400 °C) and at 3.2 mol.% Y₂O₃ (for T < ～300 °C) vs. 9 mol.% Y₂O₃ in bulk YSZ. Based on an analysis of the Raman spectra, these results are believed to result from the extended meta-stability of the cubic phase to reduced yttria levels at nanometric grain sizes.     

A study of virtual lithography process for polymer directed self-assembly

For the feature size scaling down to tens of nanometers, the top-down approaches are getting more severe because the extremely ultra-violet (EUV) technique, the high-index fluid-based immersion ArF lithography, and the double patterning technology (DPT) under development may be cover one or two generations. An alternative technology to extend lithography patterning beyond current resolution limits is to combine the top-down lithography and bottom-up assembly.In this paper, an directed self-assembly lithography process of “bottom-up” block copolymer self-assembly, is modeled and simulated in molecular-scale. Impacts of block polymer components on pattern formation are analyzed and discussed.     

Defect‐Mediated Polarization Switching in Ferroelectrics and Related Materials: From Mesoscopic Mechanisms to Atomistic Control

The plethora of lattice and electronic behaviors in ferroelectric and multiferroic materials and heterostructures opens vistas into novel physical phenomena including magnetoelectric coupling and ferroelectric tunneling. The development of new classes of electronic, energy‐storage, and information‐technology devices depends critically on understanding and controlling field‐induced polarization switching. Polarization reversal is controlled by defects that determine activation energy, critical switching bias, and the selection between thermodynamically equivalent polarization states in multiaxial ferroelectrics. Understanding and controlling defect functionality in ferroelectric materials is as critical to the future of oxide electronics and solid‐state electrochemistry as defects in semiconductors are for semiconductor electronics. Here, recent advances in understanding the defect‐mediated switching mechanisms, enabled by recent advances in electron and scanning probe microscopy, are discussed. The synergy between local probes and structural methods offers a pathway to decipher deterministic polarization switching mechanisms on the level of a single atomically defined defect.     

Esterification of Acrylic Acid with 1,4‐Butanediol in a Batch Distillation Column Reactor over Amberlyst 15 Catalyst

The esterification reaction of acrylic acid (AA) with 1,4‐butanediol (BD) to produce 4‐hydroxybutyl acrylate (HBA) was carried out in a batch reactive distillation mode over the Amberlyst 15 catalyst. The reactive distillation was highly desirable to increase the reaction rate of BD and eventually to obtain the high purity of HBA because the unreacted BD was not easily separable to the produced HBA after the reaction. The reaction pressure below 760 mm Hg was used to remove the by‐product water from the reaction zone. The air‐bubbling operation was successfully applied to prevent the polymerization of reactants and products under the vacuum condition (400 ～ 760 mm Hg). The reaction rates were strongly dependent on the reaction pressure, especially, the reaction rate of BD disappearance. The increased reaction rate of BD by the reactive distillation enabled to produce a high purity of HBA.     

Fine-sized BaMgAl10O17:Eu phosphor powders prepared by spray pyrolysis from the spray solution with BaF2 flux

Fine-sized BaMgAl₁₀O₁₇:Eu²⁺ phosphor powders with plate-like morphology were prepared by spray pyrolysis process. The effects of ratio of BaF₂ and Ba(NO₃)₂ used as the source materials of Ba component on the morphological and optical properties of the BaMgAl₁₀O₁₇:Eu²⁺ phosphor powders were investigated. BaF₂ was used as the flux material as well as the source material of Ba component. The phosphor powders prepared from the spray solution with the same mole concentrations of BaF₂ and Ba(NO₃)₂ had fine size, plate-like morphology and narrow size distribution. The addition of BaF₂ as the source material of Ba component increased the photoluminescence intensities of the phosphor powders. The phosphor powders prepared from the spray solution with the ratios of BaF₂ and Ba(NO₃)₂ larger than 1 had the similar photoluminescence intensities to that of the commercial product.     

A bioreactor with an internal contactor for primary recovery of bovine serum albumin from yeast suspension

In this paper the internal contactor is a newly developed device for the primary recovery of protein from crude feedstock. Ion exchanges (DEAE-Streamline) are confined inside the internal contactor in a stirred tank. Interactions between the ion exchange in the internal contactor and protein (BSA) in yeast suspension have been studied. For better performance, two strategies are considered: to determine the ion conductivity of a simulated yeast suspension, and to select the optimum process time for adsorption. In this system, advantages of both batch adsorption and expanded bed adsorption were obtained. Furthermore, in denser cell concentration (50 g/L) where EBA cannot be operated, the primary recovery was carried out in 1–2 hr. The efficiency of yield is higher than 80% in this condition.