In this paper, sub-20 nm ferroelectric PVDF–TrFE copolymer nanograss structures with aspect ratios up to 8.9 were developed. This study demonstrated sub-20 nm PVDF–TrFE nanograss structures that are nanoimprinted using a silicon nanograss mold in a single step. Vertically oriented PVDF–TrFE nanopillars were poled using the developed flip-stacking poling method. According to the PFM measurements, the piezoelectricity of flat thin films fabricated in this work reaches 14.0 pm/V. The maximum output voltage of the single PVDF–TrFE nanopillar was 526 mV, and the maximum piezoelectricity of the single PVDF–TrFE nanopillar was 210.4 pm/V. The piezoelectricity of the developed PVDF–TrFE nanograss structures was 5.19 times larger than that of the PVDF–TrFE flat thin films. The developed technique is simple, economical, and easy to fabricate. The developed ferroelectric PVDF–TrFE copolymer nanograss structures, which showed enhanced piezoelectricity compared to the PVDF–TrFE flat thin films, have potential applications in nanotip-based protein biosensors, nanotip-based tactile sensors, and power nanogenerators.

In this paper, we report the optical constants (refractive index, extinction coefficient) of self-assembled hollow gold nanoparticle (HGN) monolayers determined through spectroscopic ellipsometry (SE). We prepared a series of HGNs exhibiting various morphologies and surface plasmon resonance (SPR) properties. The extinction coefficient (k) curves of the HGN monolayers exhibited strong SPR peaks located at wavelengths that followed similar trends to those of the SPR positions of the HGNs in solution. The refractive index (n) curves exhibited an abnormal dispersion that was due to the strong SPR extinction. The values of Δn and k max both correlated linearly with the particle number densities. From a comparison of the optical constant values of HGNs with those of solid Au nanoparticles (NPs), we used SE measurements to demonstrate a highly sensitive Si-based chemical sensor. HGNs display a slightly lower value of k at the SPR peak but a much higher sensitivity to changes in the surrounding medium than do solid Au NPs.

A three-dimensional (3D) fin-shaped field-effect transistor structure based on III-V metal-oxide-semiconductor field-effect transistor (MOSFET) fabrication has been demonstrated using a submicron GaAs fin as the high-mobility channel. The fin-shaped channel has a thickness-to-width ratio (TFin/WFin) equal to 1. The nano-stacked high-k Al2O3 dielectric was adopted as a gate insulator in forming a metal-oxide-semiconductor structure to suppress gate leakage. The 3D III-V MOSFET exhibits outstanding gate controllability and shows a high Ion/Ioff ratio > 105 and a low subthreshold swing of 80 mV/decade. Compared to a conventional Schottky gate metal–semiconductor field-effect transistor or planar III-V MOSFETs, the III-V MOSFET in this work exhibits a significant performance improvement and is promising for future development of high-performance n-channel devices based on III-V materials.

Farm ponds are important habitats for amphibians, birds, and other wildlife. In Taiwan, artificial ponds were originally created on farmlands for irrigation purposes and the needs of the domestic water supply. Although pond creation is a typical farming practice, it also provides habitats for pond-breeding amphibians. Thus, it is essential to understand the current status of habitats and their vulnerability regarding urgent conservation needs for target species. Günther's frog (Hylarana guentheri), a pond-breeding amphibian, has a high sensitivity towards surrounding environmental changes, and can be used as an indicator species to assess habitat suitability. The purpose of this study is to establish a systematic framework to assess the habitat suitability of pond-breeding amphibians by using Günther's frog as a pilot-study species. First, we collected frog survey data from Chiayi, Taiwan, from winter 2013 to spring 2015, and investigated the present status of the environmental conditions around the ponds. Next, expert questionnaires and the fuzzy Delphi method were applied to establish the hierarchical evaluation criteria regarding the habitat suitability assessment. Four indicators: the aquatic environments of farm ponds; the terrestrial environments around ponds; landscape connectivity; and the conservation perceptions of the residents, were determined as first-layer factors in the assessment criteria, while ten other indicators were defined as second-layer factors. Based on the established assessment criteria, we performed in situ habitat suitability evaluations on 69 selected sites and surveyed the perceptions of the residents using questionnaires. Results revealed that 19% of locations were rich in frog species with a high habitat suitability. However, 67% of locations showed signs of habitat degradation, which may imply a higher need in practicing habitat improvement or restoration. The Kappa value was 0.6061, which indicated a high reliability of the habitat suitability assessment model. In brief, the proposed method can be applied, not only to assess the sustainability of frog habitats and degradation risks, but also to determine which locations may require future attention regarding conservation implementation. Furthermore, findings in this study provide useful background knowledge to all associated stakeholders when designing and implementing plans of wildlife habitat management and restoration at farm ponds.

Powder metallurgy is the conventional process for the production of CrCu alloys. Enhanced vacuum sintering techniques and the use of HIP processes can be applied to obtain higher densities and decreased porosity in the sintered parts. In this study, the optimal sintering process of Cr50Cu50 alloy targets is 1270°C for 1 h; a high density and low electrical resistivity of the alloy targets is obtained. The experimental results also indicate that the relative density of the Cr50Cu50 vacuum sintering targets can reach 99.42%, and that apparent porosity decreases to 0.54% after 1050°C at 175 MPa for 4 h of HIP treatments. The crystal property of sintered CrCu alloy is improved, and the resistivity decreased to 589 © 10 ¹8 ³·cm; IACS is also enhanced to 29.27% via HIP optimal treatment. This study shows that the high density and optimum properties of sintered Cr50Cu50 alloy targets can be produced by utilizing a suitable HIP treatment.