Interfacial Reaction between Zn-Al-Based High-Temperature Solders and Ni Substrate

The Zn-Al(-Cu) eutectic alloys (melting point 381°C) are candidates for use as Pb-free high-temperature solders as a substitute for Pb-based solders, which are suitable for severe working environments such as the engine room of hybrid vehicles equipped with an inverter system as well as a heat engine. In this study, the interfacial reaction between Zn-Al(-Cu) alloys and the Ni substrate during soldering, aging, and thermal cycling was investigated. Semiconductor chips and Ni substrates were soldered with Zn-Al(-Cu) alloys at various temperatures under a nitrogen atmosphere. The soldered assemblies were then heat-treated at 200°C and 300°C to examine the microstructural evolution at the soldered interface. The effect of severe thermal cycles between −40°C and 250°C in air on the microstructure and fracture behavior at the solder joint was investigated. Even after a 1000-cycle test, the thickness of the Al₃Ni₂ layer formed at the interface between the Zn-Al-based solder and the Ni substrate, which is responsible for the damage of the soldered assemblies, was quite small.     

Facile synthesis of Au-nanoparticle/polyoxometalate/graphene tricomponent nanohybrids: an enzyme-free electrochemical biosensor for hydrogen peroxide

A green, facile, one-pot synthesis of well-defined Au NPs@POM-GNSs tricomponent nanohybrids is reported (POM stands for polyoxometalate and GNSs for graphene nanosheets). The synthesis is convenient, rapid and environmentally friendly. The POMs serve as both reducing, encapsulating molecules, and bridging molecules; this avoids the introduction of other organic toxic molecules. Characterization using transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy analysis is performed, and the structure of the prepared nanohybrids of Au NPs@POM-GNSs is verified. Most importantly, the amperometric measurements show the Au NPs@POM-GNSs nanohybrids have high catalytic activity with good sensitivity, good long-term stability, wide linear range, low detection limit, and fast response towards H(2)O(2) detection for application as an enzyme-free biosensor. Transformation of the POMs during H(2)O(2) detection does not affect the catalytic activities of the nanohybrids. Thus, the synergistic effect of Au NPs and GNSs in the nanohybrids leads to the enhanced catalytic property.     

Uptake of VIV ion of vanadocene dichloride by apo-transferrin investigated by ESR spectroscopy

The action mechanism of vanadocene dichloride, Cp₂VCl₂ (Cpη⁵-C₅H₅), has been investigated by interaction with apo-transferrin and albumin for its promising antitumor activities. Our ESR spectral studies clearly showed that V^IV ion is readily transported from vanadocene chloride to transferrin, and the V^IV ions are captured at the Fe(III) binding sites of transferrin as a VO²⁺ form. We also observed that some binuclear VO²⁺ complexes can efficiently transport the VO²⁺ ions to the apo-transferrin.     

Catalytic NO–H2–CO–O2 reactions over Pt-supported mesoporous yttrium oxide

Catalytic light-off of a stream of NO, H₂, CO in an excess O₂ has been studied over various metal oxides loading 1 wt% Pt. Because a low-surface area Y₂O₃ (<5 m² g⁻¹) was found to exhibit the highest de-NO_x activity, a mesoporous Y₂O₃ was then synthesized from an yttrium-based surfactant mesophase templated by dodecyl sulfate , which was anion-exchanged by acetate (AcO = CH₃COO⁻). The product showed a 3-D mesoporosity with a large surface area (396 m² g⁻¹) and the Pt-supported catalyst achieved much improved light-off characteristics suitable for the low-temperature de-NO_x in the presence of CO and excess O₂.     

Protein adsorption on spark plasma sintered 2d‐, 3d‐ and lamellar type mesoporous silicate compacts

The preparation of lamellar type mesoporous silica (MPS) compact through the spark plasma sintering (SPS) and the adsorption/desorption of protein onto MPS compact are reported to be compared with those onto 2d‐hexagonal and 3d‐cubic type MPS compacts. A lamellar‐type MPS powder (MPS‐la) was prepared using triblock copolymer, PEO₅ PPO₆₈ PEO₅, and was compacted in a carbon die and heated at 500°C for 5 min under uniaxial pressure. The products are referred to as MPS‐la‐500. The MPS compacts keep the lamellar type mesoporous configuration. The adsorbed amount of protein onto MPS‐la‐500 was 100 mg/g, while that on MPS‐la was 130 mg/g, and the former decreased by 23%. However, its decreasing ratio of the protein adsorption on MPS‐la‐500 was less than those of 2d‐hexagonal and 3d‐cubic type MPS compacts, which were 73 and 34%, respectively. The released amount of protein into PBS solution from MPS‐la‐500, which was soaked in the protein solution for 48 h, increased with the soaking time, while those from 2d‐ and 3d‐type MPS compacts reached to plateau for 4 h of soaking. The lamellar type MPS compact was found to be easier to absorb and release proteins, which may be due to the large aperture of the mesoporous configuration.Inspec keywords: silicon compounds, polymer blends, mesoporous materials, adsorption, plasma materials processing, proteins, sintering, powders, desorption, compaction, molecular biophysicsOther keywords: lamellar‐type MPS powder, PEO5PPO68PEO5, MPS‐la‐500, protein adsorption, lamellar type MPS compact, 3d‐cubic type MPS compact, spark plasma sintering, 2d‐hexagonal type MPS compacts, lamellar type mesoporous silicate compacts, lamellar type mesoporous silica compact, desorption, triblock copolymer, uniaxial pressure, PBS solution, protein solution, soaking time, temperature 500.0 degC, time 5.0 min, time 48.0 hour, time 4.0 hour, SiO₂      

Thermoluminescence and induced absorption in X-ray-irradiated CdS-doped glasses

Thermoluminescence of X-ray-irradiated CdS-doped glasses has been measured, and relation between thermoluminescence and induced absorption in the X-ray-irradiated CdS-doped glasses has been investigated. The effect of thermal annealing and the X-ray energy dependence of thermoluminescence is different from that on the induced absorption. Therefore, defects, which are responsible for thermoluminescence, are considered to be different from those responsible for the induced absorption.     

A neural network approach to predict tactile comfort of applying cosmetic foundation

An expert system has been developed to predict the degree of tactile comfort during the application of cosmetic foundation. A tribometer using compliant silicone-rubber surfaces was developed to perform 4 sliding tests and an oscillating test. From the tests for 20 different samples, 11 feature quantities were identified. The values of the feature quantities were used as the inputs to an artificial neural network, and the scores of tactile sensations were obtained as the outputs. The neural network, after supervised learning, could predict 5 types of emotional tactile comfort with high accuracy.     

Prevalence of primary chronic open-angle glaucoma in Ivory Coast

BACKGROUND: The aim of this study was to determine and analyze the rate of chronic open-angle glaucoma in C?te d'Ivoire. METHODS: The prevalence of chronic glaucoma (POAG) was retrospectively evaluated in a population of 33,000 patients attending a private clinic including 24,751 black subjects and 8,249 white subjects. Patients with a cup/disc superior to 0.5 and an abnormal Goldmann's kinetic perimetry, associated with (POAG with "elevated" pressure or not (POAG with normal pressure) with an intraocular hypertension (intra ocular pressure superior to 21 mmHg) were distinguished. RESULTS: Prevalence was from 2.1% for the black subjects and 0.75% for the white subjects. Mean age was 46.4 +/- 12.5 years for blacks subjects versus 52.8 +/- 12.2 years for white subjects. This prevalence increased with age in both populations. Out of 571 cases of POAG, 465 (81.4%) were previously known and 450 of them were treated; 38.5% of the POAG cases had normal pressure. CONCLUSION: Primary open-angle glaucoma is a major health care problem emphasizing the need for detection and prevention in C?te d'Ivoire.