Evaluation of Sn0.9_{0.9}Fe0.1_{0.1}O2‐δ_{2‐ δ} as Potential Anode Material for Sodium‐Ion Batteries

The introduction of transition metals such as iron in oxides of alloying elements as, for instance, SnO$_2$ has been proven to enable higher capacities and superior charge storage performance when used as lithium-ion electrode materials. Herein, we report the evaluation of such electrode materials, precisely (carbon-coated) Sn$_{0.9}$Fe$_{0.1}$O$_{2−δ}$(−C), for sodium-ion battery applications. The comparison with SnO$_2$ as reference material reveals the beneficial impact of the presence of iron in the tin oxide lattice, enabling higher specific capacities and a greater reversibility of the de-/sodiation process – just like for lithium-ion battery applications. The overall achievable capacity, however, remains relatively low with about 300 mAh g$^{−1}$ and up to more than 400 mAh g$^{−1}$ for Sn$_{0.9}$Fe$_{0.1}$O$_{2-δ}$ and Sn$_{0.9}$Fe$_{0.1}$O$_{2−δ}$-C, respectively, compared to the theoretical specific capacity of more than 1,300 mAh g$^{−1}$ when assuming a completely reversible alloying and conversion reaction. The subsequently performed ex situ/operando XRD and ex situ TEM/EDX analysis unveils that this limited capacity results from an incomplete de-/sodiation reaction, thus, providing valuable insights towards an enhanced understanding of alternative reaction mechanisms for sodium-ion anode material candidates

In Utero Exposure to Dioxins and Polychlorinated Biphenyls and Its Relations to Thyroid Function and Growth Hormone in Newborns

The aim of this study is to examine the association between transplacental exposure to dioxins/polychlorinated biphenyls (PCBs) and thyroid and growth hormones in newborns. We recruited 118 pregnant women, between 25 and 34 years of age, at the obstetric clinic. Personal data collected included reproductive and medical histories and physical factors. Clinicians gathered placental and umbilical cord serum upon delivery and carefully scored the 118 newborns, making both structural and functional assessments. We analyzed placentas for 17 polychlorinated dibenzo-p-dioxins and dibenzofurans and 12 dioxin-like PCB congeners with the World Health Organization–defined toxic equivalent factors, and six indicator PCBs by high-resolution gas chromatography and high-resolution mass spectrometry. We analyzed thyroid and growth hormones from cord serum using radioimmunoassay. Insulin-like growth factor (IGF)-1, IGF-binding globulin-3, and thyroxine × yroid-stimulating hormone (T(4) × TSH) were significantly associated with increased placental weight and Quetelet index (in kilograms per square meter; correlation coefficient r = 0.2–0.3; p < 0.05). Multivariate analyses showed independently and significantly decreased free T(4) (FT(4)) × TSH with increasing non-ortho PCBs (r = −0.2; p < 0.05). We suggest that significant FT(4) feedback alterations to the hypothalamus result from in utero exposure to non-ortho PCBs. Considering the vast existence of bioaccumulated dioxins and PCBs and the resultant body burden in modern society, we suggest routine screening of both thyroid hormone levels and thyroid function in newborns

Trends in transport injuries burden and risk factors among children under 14 years old in China: 1990–2019

BackgroundTransport injuries (TI) remains one of leading causes of death in children in China. This study aimed to analyze the temporal trend of disease burden and associated risk factors of TI among children aged 0–14 years in China, utilizing data from 1990 to 2019.MethodsWe retrieved data of disease burden and risk factors of TI among children aged 0–14 year in China from 1990 to 2019 from the Global Burden of Disease (GBD) dataset. We estimated incidence rate, death rate, and disability adjusted life years (DALYs) rate with a 95% uncertainty interval (95% UI), stratified by age, sex, and all type-road users. Trends in disease burden with annual percentage changes (APC) and average annual percent change (AAPC) were performed by Joinpoint regression model.ResultsThe incidence rate (AAPC = 1.18%, P < 0.001) of TI among children aged 0–14 years showed an increasing trend, whereas mortality rate (AAPC = -3.87%, P < 0.001) and DALYs rate (AAPC = -3.83%, P < 0.001) decreased annually. Notably, boys experienced a higher increase in incidence (1.30%) compared to girls (1.06%), but a faster decrease in mortality and DALYs rate (-3.90% vs. -3.82%, -3.88% vs. -3.79%, respectively) (Pall < 0.001). Declines in death rates and DALYs rates were observed across all age groups (Pall < 0.001), while remained the highest among children aged 0–4 in 2019. Among different road-type users, cyclist road injuries were identified as the primary cause of TI (182.3 cases per 100,000) while pedestrians were the group with the highest mortality (2.9 cases per 100,000) and DALYs rate (243 cases per 100,000) in 2019. Besides, alcohol use was a significant risk factors for TI, while low temperature appeared to be a protective factor.ConclusionFuture efforts must prioritize raising awareness among children and their guardians to mitigate the disease burden of TI in children. It’s critical to enhance preventive interventions for boys, children aged 0–4 and vulnerable road users such as pedestrians and cyclists in future

A Systematic Approach for Inertial Sensor Calibration of Gravity Recovery Satellites and Its Application to Taiji-1 Mission

High-precision inertial sensors or accelerometers can provide us references of free-falling motions in gravitational field in space. They serve as the key payloads for gravity recovery missions such as the CHAMP, the GRACE-type missions, and the planned Next Generation Gravity Missions. In this work, a systematic method of electrostatic inertial sensor calibrations for gravity recovery satellites is suggested, which is applied to and verified with the Taiji-1 mission. With this method, the complete operating parameters including the scale factors, the center of mass offset vector and the intrinsic biased acceleration can be precisely calibrated with only two sets of short-term in-orbit experiments. Taiji-1 is the first technology demonstration satellite of the "Taiji Program in Space", which, in its final extended phase in 2022, could be viewed as operating in the mode of a high-low satellite-to-satellite tracking gravity mission. Based on the calibration principles, swing maneuvers with time span about 200 s and rolling maneuvers for 19 days were conducted by Taiji-1 in 2022. The inertial sensor's operating parameters are precisely re-calibrated with Kalman filters and are updated to the Taiji-1 science team. Data from one of the sensitive axis is re-processed with the updated operating parameters, and the performance is found to be slightly improved compared with former results. This approach could be of high reference value for the accelerometer or inertial sensor calibrations of the GFO, the Chinese GRACE-type mission, and the Next Generation Gravity Missions. This could also shed some light on the in-orbit calibrations of the ultra-precision inertial sensors for future GW space antennas because of the technological inheritance between these two generations of inertial sensors.Comment: 24 pages, 19 figure

Origin of Aging of a P2-Nax_xMn3/4_{3/4}Ni1/4_{1/4}O2_2 Cathode Active Material for Sodium-Ion Batteries

Sodium-ion batteries (SIB) are currently being developed and commercialized as a promising new technology for cost-effective and powerful electrical energy storage. In this study, we investigate the origin of capacity fading in P2-type layered sodium cathode materials for SIBs using a micron-sized single-crystalline P2-Na$_x$Mn$_{3/4}$Ni$_{1/4}$O$_2$ model cathode active material. Using various electrochemical techniques, we identify the following aging effects upon cycling: (i) a state of charge (SOC)-independent increase in polarization, (ii) a SOC-dependent increase in polarization at high voltage, and (iii) a loss of active material due to electronic disconnection after prolonged cycling. With high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray (EDX) spectroscopy, we identify surface densification, resulting in 5–10 nm thick surface layers on cycled cathode active materials as the origin for SOC-independent increase of polarization. The corresponding oxygen loss is in accordance with gas evolution in differential electrochemical mass spectrometry (DEMS) measurements. Furthermore, with scanning electron microscopy (SEM) electrode cross sections, we identify (partly) reversible cracking at a high SOC as the cause for increased polarization depending on SOC. Operando X-ray diffraction (XRD) identifies significant anisotropic volume change, which suggests mechanical stress as the cause for cracking at a high SOC and loss of active material after prolonged cycling. We believe that the herein provided understanding on the aging of this highly attractive class of cathode active materials for SIBs will enable the development of future powerful and stable layered oxide cathode materials for SIBs

Efficient Passivation and Low Resistivity for p+-Si/TiO2Contact by Atomic Layer Deposition

The monolithic, two-terminal (2-T) perovskite/silicon tandem solar cell is a promising candidate to increase the power conversion efficiency beyond the theoretical limit of 29.4% for crystalline silicon solar cells. To achieve a high-efficiency 2-T tandem, it is critical to have an interface that can connect the bottom and top subcells together so that both efficient passivation and good electrical contact are achieved. The majority of works done to date in this area, applied an intermediate layer as the recombination layer between perovskite and silicon, which incurs higher manufacturing costs and an additional processing step. Here we demonstrate a unique and straightforward interlayer-free approach to passivating highly boron-doped low-resistivity n-Si using a thin layer of TiO2 fabricated by atomic layer deposition (ALD) and a suitable pretreatment of the silicon surface. The passivation of this film is found to be superior to that of thermally grown SiO2 formed at high temperatures over 700 °C. The TiOX layer leads to a sufficiently low contact resistance of 0.45 Ω.cm2 and high-quality passivation with a recombination current density (J0) of 152 fA/cm2. The structure is applicable to both perovskite/Si tandems and single-junction Si solar cells.We acknowledge the support of the Australian Renewable Energy Agency (ARENA), the Australian Centre for Advanced Photovoltaics (ACAP), and the ANFF ACT Node in carrying out this research. H.T.N. acknowledges the fellowship support of the Australian Centre for Advanced Photovoltaics. T.P.W. is the recipient of an Australian Research Council Future Fellowship (Project No. FT180100302) funded by the Australian Government

In-situ formation and evolution of atomic defects in monolayer WSe2 under electron irradiation

Transition metal dichalcogenide (TMD) monolayers such as MoS2, MoSe2, MoTe2, WS2 and WSe2 have attracted significant interest due to their remarkable electronic and optical properties, exhibiting a direct band gap, enabling usability in electronics and optics. Their properties can be altered further by the introduction of lattice defects. In this work, the dynamics of the formation of electron-beam-induced lattice defects in monolayer WSe2 are investigated by in-situ spherical and chromatic aberration-corrected low-voltage transmission electron microscopy. We show and analyze the electron-dose-limited life of a monolayer WSe2 from the formation of isolated Se vacancies over extended defects such as vacancy lines, mirror twin boundaries (MTBs) and inversion domains towards the loss of W atoms leading to the formation of holes and finally the destruction of the monolayer. We identify, moreover, a new type of MTB. Our study extends the basic understanding of defect dynamics in monolayer WSe2, sheds further light on the electron radiation response and suggests new ways for engineering the in-plane architecture of TMDs

System Availability Modelling and Optimization considering Multigeneral Quality Characteristics

This paper analyzes the necessity that multigeneral quality characteristic parameters should be considered in availability modelling and optimization and then constructs an availability model including the indicators of reliability, maintainability, supportability, testability, and environmental factor. In the research process, it is assumed that the system has soft and hard failure mode, adopting mixed maintenance strategies, system delay time, and repair time, and test time are independent. On the basis of this, the single parameter, binary parameters, and multiparameters optimization were carried out with the maximum availability as the optimization function. Especially, the multiparameters availability optimization model in time dimension was designed based on particle swarm optimization. The design method was proved feasible through a numerical example, which can provide method support for the design and evaluation of general quality characteristic thresholds in the life cycle of a repairable system