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Polarization Distortion and Compensation of Circularly Polarized Emission from Chiral Metasurfaces
No full textCircularly polarized (CP) emission can be achieved by integrating emissive materials into chiral metasurfaces. Such CP light sources in integrated device platforms are desirable for important potential applications. However, the exact characterization of the polarization state in CP emission may include some errors because of the unwanted polarization distortion caused by optical components (e.g., beam splitter) in the optical setup. Here, we consider CP emission measurements from chiral metasurfaces and characterize the polarization distortion caused by the beam splitter. We first detail the procedures for the Stokes parameters and Mueller matrix measurements. Then, we directly measure the Mueller matrix of the beam splitter and retrieve the original polarization state of CP emission from our metasurface sample. Using the measured Mueller matrix of the beam splitter, we specifically identify what contributes to polarization distortion in CP emission. Our work may provide useful guidelines for the characterization and compensation of polarization distortion in general Stokes parameter measurements
Electrical Phase Modulation Based on Mid-Infrared Intersubband Polaritonic Metasurfaces
No full textElectrically reconfigurable metasurfaces that overcome the static limitations in controlling the fundamental properties of scattered light are opening new avenues for functional flat optics. This work proposes and experimentally demonstrates electrically phase-tunable mid-infrared metasurfaces based on the polaritonic coupling of Stark-tunable intersubband transitions in semiconductor heterostructures and electromagnetic modes in plasmonic nanoresonators. In the applied voltage range of -3 to +3 V, the local phase tuning of the light reflects from the metasurface, which enables the electrical control of the polarization state and wavefront of the reflected wave. Electrical beam polarization control, electrical beam diffraction control, and electrical beam steering are experimentally demonstrated as applications for local phase tunability. The proposed electrically tunable metasurfaces can easily tune the operating wavelength and function at relatively low voltages, which will enable various applications in the mid-infrared region
Individually addressable multi-touch sensors using a sweep signal for minimal wiring complexity
No full textElastic Interfacial Layer Enabled the High-Temperature Performance of Lithium-Ion Batteries via Utilization of Synthetic Fluorosulfate Additive
No full textThe key to producing high-energy Li-ion cells is ensuring the interfacial stability of Si-containing anodes and Ni-rich cathodes. Herein, 4-(allyloxy)phenyl fluorosulfate (APFS), a multi-functional electrolyte additive that forms a mechanical strain-adaptive solid electrolyte interphase (SEI) comprising LiF and polymeric species, and a thermally stable cathode-electrolyte interface containing S-O and S-F species. The radical copolymerization of vinylene carbonate (VC) with APFS via electrochemical initiation creates a spatially deformable polymeric SEI on the SiG-C (30 wt.% graphite + 70 wt.% SiC composite) anode, with large volume changes during cycling. Moreover, the APFS-promoted interfacial layers reduce Ni dissolution and deposition. Furthermore, APFS deactivates the Lewis acid PF5, thereby inhibiting hydrolyses that produce unwanted HF. These results indicate that the combined use of VC with APFS allows capacity retentions of 72.5% with a high capacity of 143.5 mAh g(-1) in SiG-C/LiNi0.8Co0.1Mn0.1O2 full cells after 300 cycles at 45 degrees C
Feasibility study on recycling into graphene material of the spent resin from a heavy water reactor
No full textTowards accurate individual tree parameters estimation in dense forest: optimized coarse-to-fine algorithms for registering UAV and terrestrial LiDAR data
No full textAccurate quantification of individual tree parameters is vital for precise forest inventory and sustainable forest management. However, in dense forests, terrestrial laser scanning (TLS), which can provide accurate and detailed forest structural measurements, is limited to capturing the complete tree structure due to the lack of upper canopy views, resulting in an underestimation of tree height. Combining TLS with unmanned aerial vehicle laser scanning (ULS) is an effective way to overcome this limitation. Thus, it is vital to register multi-platform Light Detection and Ranging (LiDAR) data for various forestry applications. This study proposed three automated and nearly parameter-free optimized coarse-to-fine algorithms (i.e. FPFH-based optimized ICP (F-OICP), RANSAC-based optimized ICP (R-OICP), and NDT-based optimized ICP (N-OICP)) to accurately register TLS and ULS point data for individual tree crown delineation and parameters (diameter at breast height (DBH) and tree height) estimations in different forest types (i.e. coniferous, mixed broadleaf-coniferous, and broadleaf). Results showed that the proposed optimized algorithms had a good registration performance, with an average RMSE of about 8.3 cm for the transformation error; and obtained stable and high accuracies of individual tree crown delineation (ITCD) (F-score: 0.7), DBH (R-2: 0.9, RMSE <1.85 cm), and tree height (R-2: 0.8, RMSE <0.37 m) estimates for three forest types. F-OICP performed the best in tree height estimation, reducing the RMSE by 48%, 12%, and 12% compared to iterative closest point (ICP), R-OICP, and N-OICP, respectively. Stand type significantly impacted ITCD and individual tree parameter estimations. The ITCD and DBH estimation accuracy of coniferous forests were marginally higher than those of broadleaf forests (F-score: 0.78 vs. 0.78, DBH RMSE: 1.57 vs. 1.74), while those of mixed broadleaf-coniferous forests were the lowest (F-score: 0.71, DBH RMSE: 2.19). The accuracies of tree height estimates in coniferous forests were the highest (R-2: 0.87, RMSE: 0.21 m), followed by mixed broadleaf-coniferous (R-2: 0.84, RMSE: 0.37 m) and broadleaf (R-2: 0.84, RMSE: 0.44 m) forests. This work developed automated, nearly parameter-free, and effective registration algorithms and recommended F-OICP to be the most appropriate for dense forests (i.e. natural secondary forests). The optimized registration algorithms facilitate the ability for the synergistic use of multi-platform LiDAR and offer appealing and promising approaches for future accurate quantification of individual tree parameters, efficient forest inventories, and sustainable forest management
Comparative insight of pesticide transformations between river and wetland systems
No full textThe widespread use of pesticides threatens the environment and ecosystems. Despite the positive effects of plant protection products, pesticides also have unexpected negative effects on nontarget organisms. The microbial biodegradation of pesticides is one of the major pathways for reducing their risks at aquatic ecosystems. The objective of this study was to compare the biodegradability of pesticides in simulated wetland and river systems. Parallel experiments were conducted with 17 pesticides based on the OECD 309 guidelines. A comprehensive analytical method, such as target screening combined with suspect and non-target screening, was performed to evaluate the biodegradation via identification of transformation products (TPs) using LC-HRMS. As evidence of biodegradation, we identified 97 TPs for 15 pesticides. Metolachlor and dimethenamid had 23 and 16 TPs, respectively, including Phase II glutathione conjugates. The analysis of 16S rRNA sequences for microbials characterized operational taxonomic units. Rheinheimera and Flavobacterium, which have the potential for glutathione S-transferase, were dominant in wetland systems. Estimation of toxicity, biodegradability, and hydrophobicity using QSAR prediction indicated lower environmental risks of detected TPs. We conclude that the wetland system is more favorable for pesticide degradation and risk mitigation mainly attributed to the abundance and variety of the microbial communities
Modified viologen-assisted reversible bromine capture and release in flowless zinc-bromine batteries
No full textFlowless Zn-Br-2 batteries exhibit considerable potential for energy storage system applications, which require the principal features of high safety, low cost, and long-term cycle stability. However, central challenges such as uncontrolled bromine crossover to anodes and aqueous electrolyte decomposition producing gases lead to a low cycle performance of batteries. Herein, we demonstrate that the introduction of bis(2-trimethylammonio) propyl viologen tetrabromide (PV(Br)(4)) onto a graphite felt (GF) electrode (PV(Br)(4)/GF) improves the cycle stability of flowless Zn-Br-2 batteries comprising a 2.5 M aqueous ZnBr2 electrolyte as the Zn and Br sources. During charging, PV(Br)(4) entraps corrosive and volatile Br2 formed inside the GF electrode via favorable interactions with the four Br- anions of PV(Br)(4), while polybromide anions are produced via an electrochemical-chemical growth mechanism. Furthermore, the PV(Br)(4) on the GF electrode reversibly releases Br- into the electrolyte through the electrochemical reduction of entrapped polybromide anions during discharging. In addition, the spatially anchoring PV(Br)(4) on a GF electrode suppresses undesired oxidative decomposition of water by minimizing the physical contact with the electrode, thereby mitigating the depletion of the electrolyte during cycling. Suppression of O-2 evolution contributes to mitigation of inhomogeneous plating and vertical growth of Zn metal at the Zn anode. Consequently, a flowless Zn-Br-2 battery with a PV(Br)(4)/GF electrode exhibits a high Coulombic efficiency of 95.6 % over 400 cycles with a current density of 10 mA cm(-2) and high areal capacity of 24.3 mAh cm(- 2)
Highly Elastic and Conductive Metallic Interconnect with Crystalline-Amorphous Nanolaminate
No full textNanolaminate with alternating layers of nanocrystalline Cu and amorphous CuZrTi is suggested as highly stretchable and conductive interconnect material in stretchable devices. 50 nm nanocrystalline Cu and 20 nm amorphous CuZrTi are the optimum thicknesses of the constituent layers, which result in an elastic deformation limit of 3.33% similar to that of the monolithic amorphous CuZrTi film and an electrical conductivity of 11.83 S/mu m corresponding to 70% of that of the monolithic nanocrystalline Cu film. The enhanced elastic deformability and conductivity of the nanolaminates enable the maintenance of the interconnect performance for cyclic stretching with a tensile strain of 114% in the form of a free-standing serpentine structure and a tensile strain of 30% in the form of an ordinary circular coil on an elastomer substrate