Advanced Nanomatericals for Solar Photocatalysis

Heterogeneous photocatalysis using semiconductors and renewable solar energy has been regarded as one of the most promising processes to alleviate and even solve both the world crises of energy supply and environmental pollution. Recently, numerous semiconducting materials and its composites have been studied for their photocatalytic applications. In this chapter, we briefly summarize recent progress in the binary oxide system (including TiO2 and α-Fe2O3), ternary oxide (Bi system), and the semiconducting materials and their composites which have remarkable applications in photocatalytic degradation of toxic pollutants, hydrogen production and as an adsorbent for wastewater treatment. In addition, we highlight the challenges and opportunities when we implement photocatalytic materials to help on the development of energy research and find ways to approach major problems

Solving a type of biobjective bilevel programming problem using NSGA-II

AbstractThis paper considers a type of biobjective bilevel programming problem, which is derived from a single objective bilevel programming problem via lifting the objective function at the lower level up to the upper level. The efficient solutions to such a model can be considered as candidates for the after optimization bargaining between the decision-makers at both levels who retain the original bilevel decision-making structure. We use a popular multiobjective evolutionary algorithm, NSGA-II, to solve this type of problem. The algorithm is tested on some small-dimensional benchmark problems from the literature. Computational results show that the NSGA-II algorithm is capable of solving the problems efficiently and effectively. Hence, it provides a promising visualization tool to help the decision-makers find the best trade-off in bargaining

Graphene, Transition Metal Dichalcogenides, and Perovskite Photodetectors

Recent years have witnessed a tremendous progress in 2D materials photodetector. Their unique properties including wide photoresponse wavelength, passivated surfaces, strong interaction with incident light, and high mobility enable dramatical superiority in photodetector application. The photophysics, device structure, working mechanism, and performance of three kinds of 2D materials photodetectors including graphene, transition metal dichalcogenides (TMDs), and halide perovskite are discussed in detail to give a profound understanding for the readers. In addition, we highlight the challenges and opportunities faced in studying 2D materials photodetector, and various strategies are summarized to help on the development of photodetection research and find ways to approach major problems

Simultaneous state and actuator fault estimation for satellite attitude control systems

AbstractIn this paper, a new nonlinear augmented observer is proposed and applied to satellite attitude control systems. The observer can estimate system state and actuator fault simultaneously. It can enhance the performances of rapidly-varying faults estimation. Only original system matrices are adopted in the parameter design. The considered faults can be unbounded, and the proposed augmented observer can estimate a large class of faults. Systems without disturbances and the fault whose finite times derivatives are zero piecewise are initially considered, followed by a discussion of a general situation where the system is subject to disturbances and the finite times derivatives of the faults are not null but bounded. For the considered nonlinear system, convergence conditions of the observer are provided and the stability analysis is performed using Lyapunov direct method. Then a feasible algorithm is explored to compute the observer parameters using linear matrix inequalities (LMIs). Finally, the effectiveness of the proposed approach is illustrated by considering an example of a closed-loop satellite attitude control system. The simulation results show satisfactory performance in estimating states and actuator faults. It also shows that multiple faults can be estimated successfully

Era of Digital Health: A Review of Portable and Wearable Affinity Biosensors

Digital health facilitated by wearable/portable electronics and big data analytics holds great potential in empowering patients with real‐time diagnostics tools and information. The detection of a majority of biomarkers at trace levels in body fluids using mobile health (mHealth) devices requires bioaffinity sensors that rely on “bioreceptors” for specific recognition. Portable point‐of‐care testing (POCT) bioaffinity sensors have demonstrated their broad utility for diverse applications ranging from health monitoring to disease diagnosis and management. In addition, flexible and stretchable electronics‐enabled wearable platforms have emerged in the past decade as an interesting approach in the ambulatory collection of real‐time data. Herein, the technological advancements of mHealth bioaffinity sensors evolved from laboratory assays to portable POCT devices, and to wearable electronics, are synthesized. The involved recognition events in the mHealth affinity biosensors enabled by bioreceptors (e.g., antibodies, DNAs, aptamers, and molecularly imprinted polymers) are discussed along with their transduction mechanisms (e.g., electrochemical and optical) and system‐level integration technologies. Finally, an outlook of the field is provided and key technological bottlenecks to overcome identified, in order to achieve a new sensing paradigm in wearable bioaffinity platforms

SAMRS: Scaling-up Remote Sensing Segmentation Dataset with Segment Anything Model

The success of the Segment Anything Model (SAM) demonstrates the significance of data-centric machine learning. However, due to the difficulties and high costs associated with annotating Remote Sensing (RS) images, a large amount of valuable RS data remains unlabeled, particularly at the pixel level. In this study, we leverage SAM and existing RS object detection datasets to develop an efficient pipeline for generating a large-scale RS segmentation dataset, dubbed SAMRS. SAMRS totally possesses 105,090 images and 1,668,241 instances, surpassing existing high-resolution RS segmentation datasets in size by several orders of magnitude. It provides object category, location, and instance information that can be used for semantic segmentation, instance segmentation, and object detection, either individually or in combination. We also provide a comprehensive analysis of SAMRS from various aspects. Moreover, preliminary experiments highlight the importance of conducting segmentation pre-training with SAMRS to address task discrepancies and alleviate the limitations posed by limited training data during fine-tuning. The code and dataset will be available at https://github.com/ViTAE-Transformer/SAMRS.Comment: Accepted by NeurIPS 2023 Datasets and Benchmarks Trac

Ti₃C₂ MXene-based Schottky Photocathode for Enhanced Photoelectrochemical Sensing

Nanomaterials are vital to the realization of photoelectrochemical (PEC) sensing platfrom that provides the sensitive detection and quantification of low-abundance biological samples. Here, this work reports a Schottky junction-based BiOI/Ti₃C₂ heterostructure, used as a photocathode for PEC bioanalysis. Specially, we realize in situ growth of flower-like BiOI on 2D intrinsically negatively charged Ti₃C₂ MXene nanosheet that endows BiOI/Ti₃C₂ heterostructure with admirably combined merits, noting in particular the generation of built-in electric field and the decrease of contact resistance between BiOI and Ti₃C₂. Under the visible light irradiation, the BiOI/Ti₃C₂ heterostructure-modified PEC platform displays superior cathodic photocurrent signal, while PEC response cuts down with the presence of L-Cysteine (L-Cys) as a representative analyte owing to the metal-S bond formation. The “signal-off” PEC sensing strategy shows good performance in terms of sensitivity, limit of detection (LOD, 0.005 nM) and stability. This research reveals the great potentials of MXene-based heterostructure in the application field of PEC sensor establishment