Weberite Na2_2MM'F7_7 (M,M'=Redox-Active Metal) as Promising Fluoride-Based Sodium-Ion Battery Cathodes

Sodium-ion batteries are a viable alternative to lithium-ion technology due to the plentiful sodium resources. However, certain commercialization challenges, such as low specific energies and poor cycling performance of current Na-ion cathodes, still need to be addressed. To overcome these hurdles, this study explored the potential of a novel class of fluoride-based materials, specifically trigonal-type Na$_2$MM'F$_7$ (M and M' are redox-active metals) belonging to the weberite-type compounds, as promising candidates for Na-ion cathodes. Through a comprehensive assessment utilizing ab initio calculations, twelve prospective compounds were identified, demonstrating high thermodynamic stability, large gravimetric capacities (>170 mAh/g), and low net Na-ion migration barriers (<600 meV). Significantly, ten out of the twelve screened compounds exhibit high specific energies exceeding 580 Wh/kg (approximately equals to the specific energy of LiFePO$_4$), indicating their exceptional electrochemical performance. This study will pave the way for further advancements in fluoride-based electrode materials

Lu-H-N phase diagram from first-principles calculations

Using a comprehensive structure search and high-throughput first-principles calculations of 1483 compounds, this study presents the phase diagram of Lu-H-N. The formation energy landscape of Lu-H-N was derived and utilized to assess the thermodynamic stability of compounds. Results indicate that there are no stable Lu-H-N ternary structures in this system, but metastable ternary structures, such as Lu20H2N17 (C2/m), Lu2H2N (P3-m1), were observed with small Ehull (< 100 meV/atom). Moreover, applying hydrostatic pressure up to 10 GPa causes the energy convex hull of the Lu-H-N to shift its shape and stabilizes binary phases such as LuN9 and Lu10H21. Additionally, interstitial empty sites in LuH2 were noted, which may explain the formation of Lu10H21 and LuH3-xNy. To provide a basis for comparison, X-ray diffraction patterns and electronic structures of some compounds are also presented

Processing-Induced Inhomogeneity of Yield Stress in Polycarbonate Product and Its Influence on the Impact Behavior

In this study, an integrated methodology for impact analysis of polycarbonate (PC) product is proposed which incorporates the processing-induced inhomogeneity of yield stress. A previously developed model is extended to predict the inhomogeneous yield stress distribution along the specimen by using the thermal history experienced during injection molding. A strain rate-dependent elastic-plastic model combining the processing-induced yield stress is applied to model the mechanical behavior of PC. Finite element simulation for notched Izod impact test is then conducted to analyze the impact behaviors of PC specimens with different thermal histories. Numerical results of the fracture energies are compared with experimental measurements

Automatic Tracking Based on Weighted Fusion Back Propagation in UWB for IoT Devices

The global population is progressively entering an aging phase, with population aging likely to emerge as one of the most-significant social trends of the 21st Century, impacting nearly all societal domains. Addressing the challenge of assisting vulnerable groups such as the elderly and disabled in carrying or transporting objects has become a critical issue in this field. We developed a mobile Internet of Things (IoT) device leveraging Ultra-Wideband (UWB) technology in this context. This research directly benefits vulnerable groups, including the elderly, disabled individuals, pregnant women, and children. Additionally, it provides valuable references for decision-makers, engineers, and researchers to address real-world challenges. The focus of this research is on implementing UWB technology for precise mobile IoT device localization and following, while integrating an autonomous following system, a robotic arm system, an ultrasonic obstacle-avoidance system, and an automatic leveling control system into a comprehensive experimental platform. To counteract the potential UWB signal fluctuations and high noise interference in complex environments, we propose a hybrid filtering-weighted fusion back propagation (HFWF-BP) neural network localization algorithm. This algorithm combines the characteristics of Gaussian, median, and mean filtering, utilizing a weighted fusion back propagation (WF-BP) neural network, and, ultimately, employs the Chan algorithm to achieve optimal estimation values. Through deployment and experimentation on the device, the proposed algorithm’s data preprocessing effectively eliminates errors under multi-factor interference, significantly enhancing the precision and anti-interference capabilities of the localization and following processes

Synthesizability of transition-metal dichalcogenides: a systematic first-principles evaluation

Transition metal dichalcogenides (TMDs) are a class of materials with various useful properties, and it is worthwhile to have a thorough evaluation of the characteristics of the TMDs, most importantly, their structural stability and exfoliability, in a systematic fashion. Here, by employing high-throughput first-principles calculations, we investigate the vast phase space of TMDs, including 16 bulk phases and 6 monolayer phases for all possible TMD combinations [comprising (3d, 4d, 5d) transition-metal cations and (S, Se, Te) anions], totaling 1386 compounds. Through the ‘bird-view’ of the as-large-as-possible configurational and chemical space of TMDs, our work presents comprehensive energy landscapes to elucidate the thermodynamic stability as well as the exfoliability of TMDs, which are of vital importance for future synthesis and exploration towards large-scale industrial applications

Towards a predictive kinetic model of 3-ethyltoluene: Evidence concerning fuel-specific intermediates in the flow reactor pyrolysis with insights into model implications

To reveal insights into high temperature kinetics of dialkylaromatics, a pyrolysis investigation of 3ethyltoluene in a flow reactor together with its reaction kinetics are presented in this work. Concentrations and chemical structures of specific species covering temperature range from 796 to 1383K at the pressure of 30 and 760 Torr were recorded and quantified by using synchrotron vacuum ultraviolet photoionization molecular-beam mass spectrometry (VUV-PI-MBMS). Important C 8 and C 9 fuel-specific intermediates relevant to primary decomposition of 3-ethyltoluene and isomerization of methylbenzyl and ethylbenzyl radicals were detected and identified. The kinetic model interpreting high temperature pyrolysis chemistry of 3-ethyltoluene was developed and reasonably predicted the measurements in this work. The model analyses reveal that the methyl-dissociated reaction from the ethyl group of 3-ethyltoluene is dominant in the fuel decomposition at low pressure, while the fuel is mainly consumed by hydrogen abstraction reactions at atmospheric pressure. The experimental observations of three methylbenzyl isomers, o -xylylene, p -xylylene, styrene and benzocyclobutene provide evidence for the relationships between products involving isomerization of methylbenzyl radicals, formation of xylylenes and decomposition of o -xylylene. The fuel structure effects of 3-ethyltoluene and m -xylene are revealed by comparing the pyrolysis behaviors in both cases. It has been found that the m -methylbenzyl-generating channel in the 3-ethyltoluene pyrolysis improved the reaction reactivity initially. Furthermore, the fuel with longer substituent ethyl group facilitates the formation of cycloalkenes and aromatics.& COPY; 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved

Clinical characteristics and outcomes of immune checkpoint inhibitor-induced pancreatic injury

Abstract Background Immune checkpoint inhibitor (ICI)-induced pancreatic injury (ICIPI) is not well documented in the literature. We aimed to describe the clinical characteristics and outcomes of patients who developed ICIPI. Methods We reviewed the medical records of consecutive patients who had a confirmed diagnosis of ICIPI (Common Terminology Criteria for Adverse Events grade ≥ 3 lipase elevation with or without clinical symptoms) from April 2011 through April 2018. Results Among the 2,279 patients received ICI and had lipase values checked thereafter, 82 (4%) developed ICIPI. Overall, 65% of patients received inhibitors of programmed death protein-1 or its ligand. Compared with asymptomatic presentation, patients who had clinical symptoms of pancreatitis (n = 32) had higher levels of lipase (P = 0.032), more frequent imaging evidence of pancreatitis (P = 0.055), and more frequent hospitalization (P < 0.001) and received intravenous fluids (P < 0.001) and steroids more frequently (P = 0.008). Twelve patients (15%) developed long-term adverse outcomes of ICIPI; three had chronic pancreatitis, four had recurrence of ICIPI, and six had subsequent diabetes. Among 35 patients who resumed ICI therapy, four (11%) had recurrence of lipase elevation. Logistic regression revealed that smoking and hyperlipidemia were associated with increased risk for long-term adverse outcomes of ICIPI, and intravenous fluids were associated with reduced risk. Patients who resumed ICI therapy survived longer than patients who discontinued ICI therapy permanently, statistically not significant (P = 0.0559). Patients who developed long-term adverse outcomes of ICIPI survived significantly longer than those who did not (P = 0.0295). The highest proportion of patients (6/21, 29%) developed long-term adverse outcomes of ICIPI was among those without typical symptoms of pancreatitis, continued ICI therapy after ICIPI, and did not receive intravenous fluids. Conclusion ICIPI can present as typical acute pancreatitis, with risk of the development of a pseudocyst, diabetes, and chronic pancreatitis. ICI resumption after ICIPI may lead to recurrence of lipase elevation without increased risk of long-term adverse outcomes, and can increase survival duration. Intravenous fluids may prevent long-term adverse outcomes, but steroids do not appear to affect outcomes of ICIPI. Asymptomatic ICIPI presentation may lead to undertreatment of ICIPI owing to underestimation of its degree, and therefore, intravenous fluid administration could potentially could potentially be benificial to prevent long-term adverse outcomes even in asymptomatic patients

Investigation of angular log-periodic folded groove waveguide slow-wave structure for low voltage Ka-band TWT

In this paper, a novel angular log-periodic folded groove waveguide (ALFGW) slow-wave structure (SWS) has been investigated theoretically and experimentally for application in Ka-band traveling-wave tubes (TWTs). The dispersion relation for the ALFGW is derived analytically, and the dispersion characteristics are calculated for a Ka-band design. The designed SWS is fabricated using oxygen-free-copper that is silver electroplated. The measured cold-test parameters show good agreement with the simulation results, with S varying from -2.7 dB to -4.8 dB and S better than -13.6 dB over the frequency range of 30-38 GHz. Simulations of beam-wave interactions using a 4850 V and 0.4 A sheet beam with a high aspect ratio of 28:1 indicate an output power of 128 W, corresponding to a maximum gain and electronic efficiency of 18.1 dB and 6.6%, respectively. Due to the log-periodic form, a higher output power, higher efficiency, wider bandwidth, and lower operating voltage are achieved as compared to a TWT based on the conventional folded groove waveguide (FGW) SWS. These results show that the proposed ALFGW SWS has good potential for application in relatively high-power wideband TWTs.Published versio