Coplanar Waveguide Bandpass Filters With Compact Size and Wide Spurious-Free Stopband Using Electromagnetic Bandgap Resonators

This work presents a novel coplanar waveguide (CPW) bandpass filter (BPF) that uses electromagnetic bandgap (EBG) resonators to reduce the size and suppress the harmonic responses. The propagation characteristic of the EBG structure is investigated by its associated equivalent circuit model. Compared with the conventional half-wavelength resonator at 5GHz, the EBG resonator is 60.5 % more compact. Based on the EBG CPW resonators, the inductively-coupled two-pole BPF with 3.8% 3-dB bandwidth and 2-dB insertion loss at 5GHz is implemented. This structure generates a 59.6% reduction in size and suppresses a second harmonic passband when compared with a conventional filter. To eliminate the third harmonic response, the proposed EBG CPW BPF further incorporates two EBG structures into its input and output ports and has the merit of a small circuit area     

Compact dual-passband filter using lumped-element coplanar waveguide resonators

A novel dual-passband filter using the unit-cell (UC) composite right/left-handed (CRLH) coplanar waveguide (CPW) open-circuited stub and the UC electromagnetic bandgap (EBG) CPW short- circuited stub is proposed. The CRLH open-circuited and EBG short-circuited stubs in parallel connection are equivalent to the dual-passband lumped-element CPW resonators within the specific frequency range. The performance of a third-order dual-passband filter with Chebyshev responses is measured and validated by full-wave simulation.     

Interconnect and contact for nanoelectronics: Metallic TaSi2 nanowires

TaSi₂ nanowires have been synthesized on Si substrate by annealing FeSi₂ thin film and NiSi₂ films at 950 °C in an ambient containing Ta vapor whose length would be grown up to 13 μm. The metallic TaSi₂ nanowires exhibit excellent electrical properties with remarkable high failure current density of 3 × 10⁸ A cm^− 2. In addition, the growth mechanism is addressed in detail, The TaSi₂ nanowires are formed in three steps: segregation of Si atoms from the FeSi₂ thin film and NiSi₂ films underlayer to form Si base, growth of TaSi₂ nanodots on Si base, and elongation of TaSi₂ nanowire along the growth direction. This simple approach promises future applications in nanoelectronics and nano-optoelectronics.     

Single-crystalline branched zinc phosphide nanostructures: synthesis, properties, and optoelectronic devices

Hierarchical tree-shaped nanostructures, nanobelts, and nanowires of Zn3P2 were synthesized in a thermal assisted laser ablation process. All nanostructures are tetragonal phased Zn3P2 with excellent crystallinity and are free from an oxidization layer according to electron microscopy and X-ray diffraction analyses. Optical measurement revealed a strong absorption from the ultraviolet to near-infrared regions. Optoelectronic devices fabricated using individual nanowires demonstrate a high sensitivity and rapid response to impinging light. A crossed heterojunction of an n-type ZnO nanowire and a p-type Zn3P2 nanowire has been characterized, and it offers a great potential for a high efficient spatial resolved photon detector.     

High‐Performance Inverted Polymer Solar Cells: Device Characterization,Optical Modeling,and Hole‐Transporting Modifications

Although high power conversion efficiencies (PCE) have already been demonstrated in conventional structure polymer solar cells (PSCs), the development of high performance inverted structure polymer solar cells is still lagging behind despite their demonstrated superior stability and feasibility for roll‐to‐roll processing. To address this challenge, a detailed study of solution‐processed, inverted‐structure PSCs based on the blends of a low bandgap polymer, poly(indacenodithiophene‐co‐phananthrene‐quinoxaline) (PIDT‐PhanQ) and [6,6]‐phenyl‐C₇₁‐butyric acid methyl ester (PC₇₁BM) as the bulk heterojunction (BHJ) layer is carried out. Comprehensive characterization and optical modeling of the resulting devices is performed to understand the effect of device geometry on photovoltaic performance. Excellent device performance can be achieved by optimizing the optical field distribution and spatial profiles of excitons generation within the active layer in different device configurations. In the inverted structure, because the peak of the excitons generation is located farther away from the electron‐collecting electrode, a higher blending ratio of fullerene is required to provide higher electron mobility in the BHJ for achieving good device performance.     

Evaluation of the effectiveness of personal protective equipment against occupational exposure to N,N-dimethylformamide

The objectives of this study were to evaluate the protective effectiveness of various personal protective equipment and the respective exposure contributions from respiratory and skin exposures of N,N-dimethylformamide (DMF) with a self-comparison study design. Two high-, four intermediate- and four low-DMF exposure workers from a synthetic leather factory were monitored in airborne DMF concentrations and N-methylformamide (NMF) concentrations in urine across four consecutive days. The workers were designated to wear no personal protective equipment on the first day. The barrier cream, rubber gloves and rubber gloves plus respirator were used on the second, third and fourth days, respectively. Person-to-personal observation was performed in the field to record all high and low exposure tasks during work for each subject. Protective effectiveness index (PEI) was used to evaluate different glove effectiveness. We concluded that the direct skin contact to the strong skin penetrates like DMF could be a more significant exposure source than the respiratory exposure in the actual occupational environment. The provision of protective equipment from skin exposure could be more important than that from respiratory exposure. The application of barrier cream could be as effective as wearing impermeable rubber gloves in the prevention from the skin penetrate in the occupational settings.     

Emulating Neuromorphic and In-Memory Computing Utilizing Defect Engineering in 2D-Layered WSeOx and WSe2 Thin Films by Plasma-Assisted Selenization Process

The neuromorphic and in-memory computing using memristors are promising for the building of the next generation computing systems. However, the diffusion dynamics of metal ions/atoms inside the switching medium impose variability in conducting filament (CF) formation, thus limiting their use in von-Neumann architecture. The precise modulation on the diffusion of metal ions/atoms and their reduction/oxidation probability holds promise to overcome the speed, size, and energy issues of present-day computers. Here, this study shows that the diffusion of metal ions can be modulated by defects inside the switching medium and confines metal filaments in a precise 1D channel. This filament confinement by the defect engineering leads to an anomalous switching mechanism with two interchangeable modes: unipolar threshold and bipolar modes. The variation between two modes can be modulated by controlling defects in the structures, leading to a uniform switching with low SET/RESET voltage variations of 17.3% and −17.6%, respectively. Moreover, the convolutional neural network is implemented to emulate synaptic plasticity and image recognition to achieve recognition accuracy of 87% due to a highly linear weight update, demonstrating its potential for in-memory computing.