Nano-Diamond-Enhanced Integrated Response of a Surface Plasmon Resonance Biosensor.

Surface plasmon resonance (SPR) sensing is a real-time detection technique for measuring biomolecular interactions on gold surfaces. This study presents a novel approach using nano-diamonds (NDs) on a gold nano-slit array to obtain an extraordinary transmission (EOT) spectrum for SPR biosensing. We used anti-bovine serum albumin (anti-BSA) to bind NDs for chemical attachment to a gold nano-slit array. The covalently bound NDs shifted the EOT response depending on their concentration. The number of ND-labeled molecules attached to the gold nano-slit array was quantified from the change in the EOT spectrum. The concentration of anti-BSA in the 35 nm ND solution sample was much lower than that in the anti-BSA-only sample (approximately 1/100). With the help of 35 nm NDs, we were able to use a lower concentration of analyte in this system and obtained better signal responses. The responses of anti-BSA-linked NDs had approximately a 10-fold signal enhancement compared to anti-BSA alone. This approach has the advantage of a simple setup and microscale detection area, which makes it suitable for applications in biochip technology.

Corrosion Resistance and Thermal Conductivity Enhancement of Reduced Graphene Oxide-BaSO4-Epoxy Composites.

The results of studies on the corrosion protectiveness and thermal conductivity of reduced graphene oxide-BaSO4 epoxy composites are reported here. A commercial epoxy resin and reduced graphene oxide (rGO) were blended with a hardening reagent and then mixed with prepared BaSO4-epoxy resin (B-epoxy). The reduced graphene oxide-BaSO4-epoxy composite (rGO-B-epoxy) paste was used to coat the surfaces of Al 7205 alloy and the corrosion and thermal properties were investigated. A corrosion test in a 3.5 wt% synthetic sea water solution showed that the composite coating containing BaSO4 had the best corrosion resistance. Moreover, the rGO-B-epoxy composite showed better protection against corrosion than the epoxy alone. The rGO-B-epoxy composite with 5 wt% BaSO4 had an in-plane coefficient of thermal conductivity of approximately 165.0 W/m K, and the in-plane thermal diffusivity was 71.38 mm2/s. In standard thermal conductivity tests, all three samples had values below 40 W/m K. The rGO-B-epoxy composites showed good surface corrosion protection and in-plane thermal conductivity.

Effect of Natural Aging on the Stress Corrosion Cracking Behavior of A201-T7 Aluminum Alloy.

The effect of natural aging on the stress corrosion cracking (SCC) of A201-T7 alloy was investigated by the slow strain rate testing (SSRT), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), conductivity, and polarization testing. The results indicated that natural aging could significantly improve the resistance of the alloys to SCC. The ductility loss rate of the unaged alloy was 28%, while the rates for the 24 h and 96 h aged alloys were both 5%. The conductivity of the as-quenched alloy was 30.54 (%IACS), and the conductivity of the 24 h and 96 h aged alloys were decreased to 28.85 and 28.65. After T7 tempering, the conductivity of the unaged, 24 h, and 96 h aged alloys were increased to 32.54 (%IACS), 32.52 and 32.45. Besides, the enthalpy change of the 24 h and 96 h aged alloys increased by 36% and 37% compared to the unaged alloy. The clustering of the solute atoms would evidently be enhanced with the increasing time of natural aging. Natural aging after quenching is essential to improve the alloy's resistance to SCC. It might be due to the prevention of the formation of the precipitation free zone (PFZ) after T7 tempering.

The Effects of a Trace Amount of Manganese and the Homogenization on the Recrystallization of Al-7Mg-0.15Ti Alloys.

The aim of this study is to explore the effects of Manganese addition and homogenization treatment on the microstructures and mechanical properties of the Al-7Mg-0.15Ti (B535.0) alloy. The optical microscopy, electrical conductivity measurements, transmission electron microscopy, scanning electron microscopy (SEM + EBSD), as well as Rockwell hardness and tensile tests, were exploited for this purpose. The main objectives are to refine the grain size, inhibit grain growth in the annealed state, and enhance the mechanical strength of the alloy. The results show that the addition of manganese to the Al-7Mg-0.15Ti alloys refined the as-cast and recrystallized grains of the alloys. During the homogenization process, Al4Mn high-temperature stable dispersoids were precipitated in the aluminum matrix. After annealing, the Al4Mn particles blocked the movement of grain boundaries during the growth of the recrystallized grains and inhibited grain growth. Consequently, the annealed alloys showed grain refinement and dispersion strengthening. The Al4Mn dispersoids of the alloys with manganese added were smaller and denser after a two-stage homogenization process compared to those that underwent a one-stage homogenization process. By contrast, for the alloys without the addition of manganese, the recrystallized grains showed normal growth after annealing, and different homogenization processes had no significantly different effects.