Controllable deposition of organic metal halide perovskite films with wafer-scale uniformity by single source flash evaporation

Conventional solution-processing techniques such as the spin-coating method have been used successfully to reveal excellent properties of organic-inorganic halide perovskites (OHPs) for optoelectronic devices such as solar cell and light-emitting diode, but it is essential to explore other deposition techniques compatible with large-scale production. Single-source flash evaporation technique, in which a single source of materials of interest is rapidly heated to be deposited in a few seconds, is one of the candidate techniques for large-scale thin film deposition of OHPs. In this work, we investigated the reliability and controllability of the single-source flash evaporation technique for methylammonium lead iodide (MAPbI(3)) perovskite. In-depth statistical analysis was employed to demonstrate that the MAPbI(3) films prepared via the flash evaporation have an ultrasmooth surface and uniform thickness throughout the 4-inch wafer scale. We also show that the thickness and grain size of the MAPbI(3) film can be controlled by adjusting the amount of the source and number of deposition steps. Finally, the excellent large-area uniformity of the physical properties of the deposited thin films can be transferred to the uniformity in the device performance of MAPbI(3) photodetectors prepared by flash evaporation which exhibited the responsivity of 0.2 A/W and detectivity of 3.82x10(11) Jones.

Deep Imbalanced Time-series Forecasting via Local Discrepancy Density

Time-series forecasting models often encounter abrupt changes in a given period of time which generally occur due to unexpected or unknown events. Despite their scarce occurrences in the training set, abrupt changes incur loss that significantly contributes to the total loss. Therefore, they act as noisy training samples and prevent the model from learning generalizable patterns, namely the normal states. Based on our findings, we propose a reweighting framework that down-weights the losses incurred by abrupt changes and up-weights those by normal states. For the reweighting framework, we first define a measurement termed Local Discrepancy (LD) which measures the degree of abruptness of a change in a given period of time. Since a training set is mostly composed of normal states, we then consider how frequently the temporal changes appear in the training set based on LD. Our reweighting framework is applicable to existing time-series forecasting models regardless of the architectures. Through extensive experiments on 12 time-series forecasting models over eight datasets with various in-output sequence lengths, we demonstrate that applying our reweighting framework reduces MSE by 10.1% on average and by up to 18.6% in the state-of-the-art model.Comment: Accepted at European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML/PKDD) 202

Investigation of the mechanism of the anomalous Hall effects in Cr2Te3/(BiSb)2(TeSe)3 heterostructure

The interplay between ferromagnetism and the non-trivial topology has unveiled intriguing phases in the transport of charges and spins. For example, it is consistently observed the so-called topological Hall effect (THE) featuring a hump structure in the curve of the Hall resistance (Rxy) vs. a magnetic field (H) of a heterostructure consisting of a ferromagnet (FM) and a topological insulator (TI). The origin of the hump structure is still controversial between the topological Hall effect model and the multi-component anomalous Hall effect (AHE) model. In this work, we have investigated a heterostructure consisting of BixSb2-xTeySe3-y (BSTS) and Cr2Te3 (CT), which are well-known TI and two-dimensional FM, respectively. By using the so-called minor-loop measurement, we have found that the hump structure observed in the CT/BSTS is more likely to originate from two AHE channels. Moreover, by analyzing the scaling behavior of each amplitude of two AHE with the longitudinal resistivities of CT and BSTS, we have found that one AHE is attributed to the extrinsic contribution of CT while the other is due to the intrinsic contribution of BSTS. It implies that the proximity-induced ferromagnetic layer inside BSTS serves as a source of the intrinsic AHE, resulting in the hump structure explained by the two AHE model

Utilization of paper sludge ash in geotechnical engineering – Review

The pulp and paper industry has grown and created tremendous volumes of byproducts (e.g., fly ash) via combustion process. Unfortunately, most of them are being landfilled; in the meantime, environmental regulations restrict the disposal in landfill because of high disposal cost and reduced land due to urbanization. Therefore, the pulp and paper industries urgently seek for its beneficial reuse and one of the most cost-effective applications is a building and construction sector, particularly its reuse as geomaterials such as stabilizing soils. This paper provides a comprehensive review of the beneficial use of the paper sludge ash (PSA) in geotechnical engineering applications. Specifically, the paper explored the state-of-the-art knowledge in the areas of physical, chemical, and mineralogical properties of PSA, geotechnical engineering properties (e.g., strength, stiffness, shear strength parameters, etc.) and field applications of the PSA. In addition, the paper looks into geo-environmental applications such as PSA\u27 s water absorption and retention performance and its performance as adsorbent for environmental contaminants

A novel approach to estimating Rt through infection networks: understanding regional transmission dynamics of COVID-19

IntroductionThe effective reproduction number (Rt) is a key indicator for monitoring and controlling infectious diseases such as COVID-19, where transmission patterns can differ substantially across demographics, regions, and phases of the pandemic. In this study, we propose a novel, network-based approach to empirically estimate Rt using detailed transmission data from South Korea. By reconstructing infector–infectee pairs, our method incorporates local factors like mobility and social distancing, offering a more precise perspective than traditional methods.MethodsWe acquired infector–infectee pair data from the Korea Disease Control and Prevention Agency (KDCA) for 2020–2021 and built infection networks to derive empirical Rt. This framework allows us to examine regional differences and the effects of social distancing measures. We also compared our results with Cori's Rt, which employs incidence data and serial interval distributions, to highlight the advantages of an infection network-based strategy.ResultsOur empirical Rt uncovered three distinct patterns. Early in the outbreak, when case numbers were low, Rt remained near 1, indicating limited transmission. During superspreading events, our estimates showed sharper peaks than Cori's method, demonstrating higher sensitivity to sudden changes. As the Delta variant emerged, our Rt values converged with Cori's, underscoring the utility of network-based methods for capturing nuanced shifts during high-variability phases.DiscussionIncorporating infection networks into Rt estimation thus provides decision-makers with timely insights for targeted interventions. Empirically reconstructing infection networks and directly estimating Rt reveal real-time transmission dynamics often overlooked by aggregated approaches. This method can significantly improve outbreak forecasts, inform more precise public health policies, and strengthen pandemic preparedness

The At-Hook Is an Evolutionarily Conserved Auto-Regulatory Domain of SWI/SNF Required for Cell Lineage Priming

The SWI/SNF ATP-dependent chromatin remodeler is a master regulator of the epigenome, controlling pluripotency and differentiation. Towards the C-terminus of the catalytic subunit of SWI/SNF is a motif called the AT-hook that is evolutionary conserved. The AT-hook is present in many chromatin modifiers and generally thought to help anchor them to DNA. We observe however that the AT-hook regulates the intrinsic DNA-stimulated ATPase activity aside from promoting SWI/SNF recruitment to DNA or nucleosomes by increasing the reaction velocity a factor of 13 with no accompanying change in substrate affinity (