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Atomically dispersed iridium catalysts on silicon photoanode for efficient photoelectrochemical water splitting
No full textStabilizing atomically dispersed single atoms (SAs) on silicon photoanodes for photoelectrochemical-oxygen evolution reaction is still challenging due to the scarcity of anchoring sites. Here, we elaborately demonstrate the decoration of iridium SAs on silicon photoanodes and assess the role of SAs on the separation and transfer of photogenerated charge carriers. NiO/Ni thin film, an active and highly stable catalyst, is capable of embedding the iridium SAs in its lattices by locally modifying the electronic structure. The isolated iridium SAs enable the effective photogenerated charge transport by suppressing the charge recombination and lower the thermodynamic energy barrier in the potential-determining step. The Ir SAs/NiO/Ni/ZrO2/n-Si photoanode exhibits a benchmarking photoelectrochemical performance with a high photocurrent density of 27.7 mA cm???2 at 1.23 V vs. reversible hydrogen electrode and 130 h stability. This study proposes the rational design of SAs on silicon photoelectrodes and reveals the potential of the iridium SAs to boost photogenerated charge carrier kinetics
Multi-Joint Assessment of Proprioception Impairments Post Stroke
No full textObjectives: To investigate shoulder, elbow and wrist proprioception impairment poststroke. Design: Proprioceptive acuity in terms of the threshold detection to passive motion at the shoulder, elbow and wrist joints was evaluated using an exoskeleton robot to the individual joints slowly in either inward or outward direction. Setting: A university research laboratory. Participants: Seventeen stroke survivors and 17 healthy controls (N=34). Inclusion criteria of stroke survivors were (1) a single stroke; (2) stroke duration <1 year; and (3) cognitive ability to follow simple instructions. Interventions: Not applicable. Main Outcome Measures: Threshold detection to passive motion and detection error at the shoulder, elbow and wrist. Results: There was significant impairment of proprioceptive acuity in stroke survivors as compared to healthy group at all 3 joints and in both the inward (shoulder horizontal adduction, elbow and wrist flexion, P<.01) and outward (P<.01) motion. Furthermore, the distal wrist joint showed more severe impairment in proprioception than the proximal shoulder and elbow joints poststroke (P<.01) in inward motion. Stroke survivors showed significantly larger detection error in identifying the individual joint in motion (P<.01) and the movement direction (P[removed
Design and implementation of a Power Management Integrated Circuit for Active EMI Filters
No full textThis paper proposes the design of power management integrated circuit (PMIC) within the active EMI filter (AEF). The buck converter has been implemented with AEF circuit. The designed IC is fabricated by TSMC 180nm BCD process. Semiconductor layout design including the above PWM signal generation circuit, 45V Power NDMOS and gate driver, and the overall size of the Buck converter is 2500??m*2500??m. The performance of the buck converter has been measured by oscilloscope after chip on board (COB) process. Input voltage range was 15v to 36v to generate 12V, and peak efficiency was measured as 66%. The AEF achieves better noise attenuation performance than 2stage L-C passive EMI filter (PEF) as about 6dB at 150khz, and the designed 1stage AEF totally attenuates 36dB from the bare noise without any resonance peak at over 1Mhz unlike the case of 2 stage L-C PEF. The active EMI filter with PMIC has been achieved better performance than larger size of passive EMI filter
Enhancing Stability and Efficiency of Perovskite Solar Cells with a Bilayer Hole Transporting Layer of Nickel Phthalocyanine and Poly(3-Hexylthiophene)
No full textTo expedite the commercialization of perovskite solar cells (PSCs), researchers are exploring the feasibility of employing nickel phthalocyanine (NiPc) as a hole transport material (HTM) due to its cost-effectiveness, excellent thermal stability, and suitability for solution coating. However, the low LUMO energy level of the NiPc may limit its ability to block photoelectrons generated in the perovskite layer from recombining with holes, which can reduce the overall efficiency of the solar cell. One solution is to use cascaded bilayers with HTMs that have relatively higher LUMO levels. In this study, a bilayer consisting of NiPc and poly(3-hexylthiophene) (P3HT) is employed as the HTM, where the P3HT exhibits vertical phase separation during the coating process. By optimizing the mixing amount of P3HT into the NiPc, a record power conversion efficiency of 23.11%, the highest reported for NiPc-based PSCs is achieved. Moreover, an excellent long-term stability is demonstrated by encapsulating the PSC in polyisobutylene, with the device retaining 90% of its initial efficiency after exposure to 85 & DEG;C and 85% relative humidity for 1000 h
Efficient and Scalable Large-Area Organic Solar Cells by Asymmetric Nonfullerene Acceptors Based on 9H-Indeno[1,2-b]pyrazine-2,3,8-Tricarbonitrile
No full textIt remains challenging to fabricate efficient, scalable large-area organic solar cells (OSCs) owing to the unfavorable morphology of photoactive blend films. To address this challenge, two asymmetric nonfullerene acceptors (NFAs) IPC1CN-BBO-IC2F and IPC1CN-BBO-IC2Cl are synthesized, where 12,13-bis(2-butyloctyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2 & PRIME;",3 & PRIME;":4 & PRIME;,5 & PRIME;]thieno[2 & PRIME;,3 & PRIME;:4,5]pyrrolo[3,2-g]thieno[2 & PRIME;,3 & PRIME;:4,5]thieno-[3,2-b]indole (BBO) is the molecular core, and two types of end groups are appended to its ends, namely the 9H-indeno[1,2-b]pyrazine-2,3,8-tricarbonitrile (IPC1CN) end group and one of 2-(5,6-dihalo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile end groups (IC2F or IC2Cl). These NFAs facilitate effective tuning of light absorption and energy levels, offer high carrier mobilities, and allow for the formation of appropriate morphologies. Note that these benefits apply even to large-area devices, unlike typical Y6-based NFAs. In addition, a random copolymer PM6-PBDBT(55) is synthesized and its energy levels are optimally matched with those of the asymmetric NFAs. The blade-coated 1 cm(2)-area OSCs based on PM6-PBDBT(55):IPC1CN-BBO-IC2Cl exhibit a PCE of 14.12%, which is higher than that of PM6-PBDBT(55)-IPC1CN-BBO-IC2F-based OSCs. More importantly, the PM6-PBDBT(55):IPC1CN-BBO-IC2Cl-based large-area (58.50 cm(2)) modules yield an impressive PCE of 11.28% with a small cell-to-module loss in fill factor. These results suggest that a combination of the asymmetric molecular design using the IPC1CN group and the terpolymer strategy will pave a new path for fabricating highly efficient and scalable large-area OSCs
Recent advances in hydrogen production through proton exchange membrane water electrolysis - a review
No full textProton exchange membrane (PEM) water electrolysis is recognized as the most promising technology for the sustainable production of green hydrogen from water and intermittent renewable energy sources. Moreover, PEM water electrolysis has several benefits such as compact system design with high operating current density, high hydrogen purity, greater energy efficiency and rapid response when combined with renewable energy sources. However, the use of costly electrocatalysts and cell components leads to expensive and limited commercial applications. In this review, various water electrolysis technologies and their technical specifications including hydrogen production costs were briefly summarized from a commercial perspective. Furthermore, we have mainly focused on PEM water electrolysis including recent developments in cell components such as membranes, gas diffusion layers, bipolar plates, and electrocatalysts. Moreover, some of the most effective results also were described and the research gaps and their challenges for cost reduction and commercialization were identified. Furthermore, we concluded by outlining our thoughts and potential solutions for future research directions that should be pursued to develop inexpensive electrocatalysts and cell components for efficient production of green hydrogen. This review aims to provide possible directions and a road map for future research and development towards the development of inexpensive PEM electrolysers
Investigation of Mg-22 levels via resonant scattering of Ne-18 + alpha
No full textThe a resonant scattering on Ne-18 was measured in inverse kinematics to understand the a-clustering of proton-rich Mg-22 nucleus, performed at the CNS Radio-Isotope Beam Separator (CRIB) of Center for Nuclear Study, University of Tokyo, located at the RIBF of RIKEN Nishina Center. The excitation function of Mg-22 was obtained for the excitation energies of 10-16 MeV by adopting the thick-target method. Several resonances were evident in the present work, which implies the existence of energy levels with large a widths. Since energy levels were not clearly observed at the astrophysically important energy range, upper limits on the Ne-18 (a, a)Ne-18 cross section were set. The astrophysical impact was also investigated by estimating the Ne-18 (a, p)Na-21 cross section
Spectral analysis of a parsec-scale jet in M 87: Observational constraint on the magnetic field strengths in the jet
No full textContext. Because of its proximity and the large size of its black hole, M 87 is one of the best targets for studying the launching mechanism of active galactic nucleus jets. Currently, magnetic fields are considered to be an essential factor in the launching and accelerating of the jet. However, current observational estimates of the magnetic field strength of the M 87 jet are limited to the innermost part of the jet (less than or similar to 100 r(s)) or to HST-1 (similar to 10(5) r(s)). No attempt has yet been made to measure the magnetic field strength in between. Aims. We aim to infer the magnetic field strength of the M 87 jet out to a distance of several thousand r(s) by tracking the distance-dependent changes in the synchrotron spectrum of the jet from high-resolution very long baseline interferometry observations. Methods. In order to obtain high-quality spectral index maps, quasi-simultaneous observations at 22 and 43 GHz were conducted using the KVN and VERA Array (KaVA) and the Very Long Baseline Array (VLBA). We compared the spectral index distributions obtained from the observations with a model and placed limits on the magnetic field strengths as a function of distance. Results. The overall spectral morphology is broadly consistent over the course of these observations. The observed synchrotron spectrum rapidly steepens from alpha(22 - 43 GHz) similar to -0.7 at similar to 2 mas to alpha(22 - 43 GHz) similar to -2.5 at similar to 6 mas. In the KaVA observations, the spectral index remains unchanged until similar to 10 mas, but this trend is unclear in the VLBA observations. A spectral index model in which nonthermal electron injections inside the jet decrease with distance can adequately reproduce the observed trend. This suggests the magnetic field strength of the jet at a distance of 2-10 mas (similar to 900 r(s) - similar to 4500 r(s) in the deprojected distance) has a range of B = (0.3-1.0 G)(z/2mas)(-0.73). Extrapolating to the Event Horizon Telescope scale yields consistent results, suggesting that the majority of the magnetic flux of the jet near the black hole is preserved out to similar to 4500 r(s) without significant dissipation
A New Approach to Empirical Mode Decomposition Based on Akima Spline Interpolation Technique
No full textThe objective of this research work is to extend the scope of the empirical mode decomposition (EMD) algorithm, as an efficient tool to decompose the nonlinear and non-stationary time series. For EMD to be widely applicable, the extension utilizes both clean and noisy data sets. When constructing upper and lower envelopes, the proposed algorithm utilizes the Akima spline interpolation technique rather than a cubic spline. The proposed EMD is called Akima-EMD, which is used to identify non-informative fluctuations in the signal, such as noise, outliers, and ultra-high frequency components, and to break down the clean and chaotic data into various components to avoid distortion. It has been shown through synthetic as well as real-world time series data analysis that the proposed method successfully extracts noise in the form of the first IMF from the data
