An Angle-Stable Ultra-Wideband Single-Layer Frequency Selective Surface Absorber

An ultra-wideband polarization-insensitive frequency selective surface (FSS) absorber is proposed for S to K-band applications. The absorber comprises two compensation slabs, a lossy FSS layer and a grounded dielectric plate. The FSS unit cell is a combination of a second-order Chinese knot and a cross. To enhance the bandwidth and angular stability of the single-layer FSS absorber, a compensation layer composed of FR4 and polymethyl methacrylate (PMMA) slabs is incorporated. The proposed FSS absorber demonstrates a remarkable absorption rate of over 90% within the frequency range of 3.1–22.1 GHz, exhibiting a fractional bandwidth of 150.8%. Even when subjected to an oblique incidence of 45°, the absorber maintains an 80% absorption rate in the frequency range of 4.4–19.1 GHz for both TE and TM polarizations. The total thickness of the FSS absorber is 0.0848 λL (the wavelength at the lowest cutoff frequency), and only 1.08 times the Rozanov limit. To validate the design, a prototype of the proposed absorber was fabricated and measured. Good agreements were observed between the simulations and measurements

Single Phase Ternary Pt-Ru-Os Catalysts for Direct Oxidation Fuel Cells

A catalyst composition for use in electrochemical reactor devices comprising platinum, ruthenium, and osmium and having a single phase crystal structure comprising a face centered cubic unit cell. In accordance with a particularly preferred embodiment, in atomic percentages, platinum comprises about 65% of the catalyst composition, ruthenium comprises about 25% of the catalyst composition, and osmium comprises about 10% of the catalyst composition.Sponsorship: Illinois Institute of TechnologyUnited States Paten

Continuous and Sensitive Acid Phosphatase Assay Based on a Conjugated Polyelectrolyte

We report a novel continuous and sensitive fluorescence turn-on assay for ACPs, which consists of a cationic conjugated polyelectrolyte (PPE4+) and a commonly used phosphatase substrate p-nitrophenyl phosphate (pNPP). The kinetics of the ACP catalyzed hydrolysis of the substrate pNPP was monitored by the fluorescence change of PPE4+ and corresponding kinetic parameters were derived to be consistent with the literature reports. The applications of PPE4+/pNPP-based ACP assay in high-throughput screening of ACP inhibitors and detection of prostatic acid phosphotase (PAP) in vitro were demonstrated

Electrocatalyst Compositions

Compositions for use as catalysts in electrochemical reactions are described. The compositions are alloys prepared from two or more elemental metals selected from platinum, molybdenum, osmium, ruthenium, rhodium, and iridium. Also described are electrode compositions including such alloys and electrochemical reaction devices including such catalysts.Sponsorship: Penn State Research FoundationSponsorship: Illinois Institute of TechnologyUnited States Paten

Droplet-based mechanical transducers modulated by the symmetry of wettability patterns

Abstract Asymmetric mechanical transducers have important applications in energy harvesting, signal transmission, and micro-mechanics. To achieve asymmetric transformation of mechanical motion or energy, active robotic metamaterials, as well as materials with asymmetric microstructures or internal orientation, are usually employed. However, these strategies usually require continuous energy supplement and laborious fabrication, and limited transformation modes are achieved. Herein, utilizing wettability patterned surfaces for precise control of the droplet contact line and inner flow, we demonstrate a droplet-based mechanical transducer system, and achieve multimodal responses to specific vibrations. By virtue of the synergistic effect of surface tension and solid-liquid adhesion on the liquid dynamics, the droplet on the patterned substrate can exhibit symmetric/asymmetric vibration transformation when the substrate vibrates horizontally. Based on this, we construct arrayed patterns with distinct arrangements on the substrate, and employ the swarm effect of the arrayed droplets to achieve three-dimensional and multimodal actuation of the target plate under a fixed input vibration. Further, we demonstrate the utilization of the mechanical transducers for vibration management, object transport, and laser modulation. These findings provide a simple yet efficient strategy to realize a multimodal mechanical transducer, which shows significant potential for aseismic design, optical molding, as well as micro-electromechanical systems (MEMS)