Bimetallic multifunctional core@shell plasmonic nanoparticles for localized surface plasmon resonance based sensing and electrocatalysis

Smart bimetallic core@shell nanoparticles were fabricated based on gold nanoparticles (AuNPs) decorated with pH-sensitive polymer shell. Concretely, AuNPs having poly(4-vinylpyridine) (P4VP) on the surface were first fabricated through surface-initiated atom transfer radical polymerization (SI-ATRP). Then, they were mixed with selected metal precursor solutions followed by reduction using reducing agent. The metal NPs thus introduced were uniformly distributed in P4VP polymer shells. In order to explore the diversity and viable function of the resultant nanostructures, we controlled the size of AuNP, pH, selectivity of metal precursors, etc. We investigated the structural alteration during the sequential synthetic process. The bimetallic nanostructures of AuNP@P4VP nanocomposites containing another type of metal NP at the P4VP periphery exhibit a controlled sensing property in terms of the change in the refractive index of surrounding media and a typical electrocatalytic activity for methanol oxidation reaction.     

Epitaxial integration of perovskite-based multifunctional oxides on silicon

We review recent developments in the epitaxial integration of multifunctional oxide thin film heterostructures on silicon (Si). Perovskite oxides have been extensively studied for use in multifunctional devices due to a wide range of functional properties. To realize multifunctional oxide devices, these multifunctional films should be integrated directly on Si, maintaining high crystalline quality. Molecular beam epitaxy growth of epitaxial SrTiO₃ (STO) on Si provides a template for incorporating the epitaxial oxide films on Si. However, the dissimilar physical nature of Si from most oxide materials influences the properties of oxide films on Si, especially with regard to structural defects and thermal strains. Therefore, in this review, we present a comprehensive overview of epitaxial integration of various model oxide systems on Si, addressing how STO/Si can be used to explore the novel phenomenon of oxide heterostructures as well as to realize multifunctional devices.     

Structural Dynamics of C2F4I2 in Cyclohexane Studied via Time-Resolved X-ray Liquidography

The halogen elimination of 1,2-diiodoethane (C₂H₄I₂) and 1,2-diiodotetrafluoroethane (C₂F₄I₂) serves as a model reaction for investigating the influence of fluorination on reaction dynamics and solute–solvent interactions in solution-phase reactions. While the kinetics and reaction pathways of the halogen elimination reaction of C₂H₄I₂ were reported to vary substantially depending on the solvent, the solvent effects on the photodissociation of C₂F₄I₂ remain to be explored, as its reaction dynamics have only been studied in methanol. Here, to investigate the solvent dependence, we conducted a time-resolved X-ray liquidography (TRXL) experiment on C₂F₄I₂ in cyclohexane. The data revealed that (ⅰ) the solvent dependence of the photoreaction of C₂F₄I₂ is not as strong as that observed for C₂H₄I₂, and (ⅱ) the nongeminate recombination leading to the formation of I₂ is slower in cyclohexane than in methanol. We also show that the molecular structures of the relevant species determined from the structural analysis of TRXL data provide an excellent benchmark for DFT calculations, especially for investigating the relevance of exchange-correlation functionals used for the structural optimization of haloalkanes. This study demonstrates that TRXL is a powerful technique to study solvent dependence in the solution phase.     

The vibration performance experiment of Tuned Liquid damper and Tuned Liquid Column damper

Tuned Liquid damper and Tuned Liquid Column are kind of passive mechanical damper which relies on the sloshing of liquid in a rigid tank for suppressing structural vibrations. TLD and TLCD are attributable to several potential advantages —low costs; easy to install in existing structures; effective even for small-amplitude vibrations. In this paper, the shaking table experiments were conducted to investigate the characteristics of water sloshing motion in TLD (rectangular, circular) and TLCD. The parameter obtained from the experiments were wave height, base shear force and energy dissipation. The shaking table experiments show that the liquid sloshing relies on amplitude of shaking table and frequency of tank. The TLCD was more effective control vibration than TLD.     

Effect of interlayer on structure and performance of anode-supported SOFC single cells

To lower the operating temperatures in solid oxide fuel cell (SOFC) operations, anode-supported SOFC single cells with a single dip-coated interlayer were fabricated and the effect of the interlayer on the electrolyte structure and the electrical performance was investigated. For the preparation of SOFC single cells, yttria-stabilized zirconia (YSZ) electrolyte, NiO-YSZ anode, and 50% YSZ-50% strontium-doped lanthanum manganite (LSM) cathode were used. In order to characterize the cells, scanning electron microscopy (SEM) and atomic force microscopy (AFM) were utilized and the gas (air) permeability measurements were conducted for gas tightness estimation. When the interlayer was inserted onto NiO-YSZ anode, the surface roughness of anode was diminished by about 40% and dense crack-free electrolytes were obtained. The electrical performance was enhanced remarkably and the maximum power density was 0.57W/cm(2) at 800 degrees C and 0.44W/cm(2) at 700 degrees C. On the other hand, the effect of interlayer on the gas tightness was negligible. The characterization study revealed that the enhancement in the electrical performance was mainly attributed to the increase of ion transmission area of anode/electrolyte interface and the increase of ionic conductivity of dense crack-free electrolyte layer.     

Note: High speed optical profiler based on a phase-shifting technique using frequency-scanning lasers

We present a high speed optical profiler (HSOP) using frequency-scanning lasers for three-dimensional profile measurements of microscopic structures. To improve upon previous techniques for implementing the HSOP, we developed frequency-scanning lasers and a compact microscopic interferometer. The controller of the HSOP was also modified to generate proper phase-shifting steps. For measurements of step height specimens, the HSOP showed results comparable with a commercial optical profiler, even with much higher measurement speeds (up to 30 Hz). The typical repeatability of step height measurement was less than 1 nm. We also present measurements of microscopic structures to verify the HSOP's ability to perform high speed inline inspection for the semiconductor and flat-panel display industries.     

Taguchi method-based sensitivity study of design parameters representing specific strength of wire-woven bulk Kagome under compression

Wire-woven bulk Kagome (WBK) is a new truss-type cellular metal fabricated by assembling helically-formed wires. In this work, the main design parameters governing the compressive strength of WBK were selected from various geometric and material factors. The Taguchi method was used to minimize the number of experiments required to evaluate the sensitivity of each design parameter with the specific compressive strength of WBK. As numerical experiments, finite element analyses were performed to investigate the mechanical responses of WBK with various combinations of levels for selected design parameters. We found that the slenderness ratio is the dominant and most influential design parameter characterizing the specific strength of WBK, followed by the strain-hardening exponent and the yield strength of the brazed filler metal. The height of the braze normalized by the wire diameter is the least influential design parameter. In addition, an optimized design for the highest specific strength of WBK was derived.     

Ultra-sensitive Transition-Edge Sensors for the Background Limited Infrared/Sub-mm Spectrograph (BLISS)

We report progress in fabricating ultra-sensitive superconducting transition-edge sensors (TESs) for BLISS. BLISS is a suite of grating spectrometers covering 35–433?μm with R～700 cooled to 50?mK that is proposed to fly on the Japanese space telescope SPICA. The detector arrays for BLISS are TES bolometers readout with a time domain SQUID multiplexer. The required noise equivalent power (NEP) for BLISS is NEP=10^?19?W/Hz^1/2 with an ultimate goal of NEP=5×10^?20?W/Hz^1/2 to achieve background limited noise performance. The required and goal response times are τ=150?ms and τ=50?ms respectively to achieve the NEP at the required and goal optical chop frequency 1–5?Hz. We measured prototype BLISS arrays and have achieved NEP=6×10^?18?W/Hz^1/2 and τ=1.4?ms with a Ti TES (T _C=565?mK) and NEP～2.5×10^?19?W/Hz^1/2 and τ～4.5?ms with an Ir TES (T _C=130?mK). Dark power for these tests is estimated at 1–5?fW.     

Interfacial reactions for the non-stoichiometric TiB x /(100)Si system

In order to evaluate the interfacial reactions in the TiB _x /(100)Si system and the thermal stability of non-stoichiometric TiB _x films (0 B/Ti 2.5), TiB _x /Si samples prepared by a co-evaporation process were annealed in vacuum at temperatures between 300 and 1000°C. The solid phase reactions were investigated by means of sheet resistance, X-ray diffraction, transmission electron microscopy, X-ray photo-electron spectroscopy, and stress measurement. For TiB _x samples with a ratio of B/Ti 2.0, an apparent structural change is not observed even after annealing at 1000°C for 1 h. For samples with a ratio of B/Ti < 2.0, however, there are two competitive solid phase reactions: the formation of a titanium silicide layer at the interface and the formation of a stoichiometric TiB₂ layer at the surface, indicating the salicide process. The sheet resistance and the film stress in the Ti/Si and TiB _x /Si systems are well explained by the solid phase reactions.