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Efficient Chiral Ultraviolet and Deep-Blue Materials for High-Performance Circularly Polarized OLEDs
No full textHigh-performance circularly polarized organic light-emitting diodes (CP-OLEDs) with ultraviolet and deep-blue circularly polarized electroluminescence (CP-EL) are important for 3D displays, but designing short-wavelength circularly polarized luminescence (CPL) materials remains a significant challenge. Herein, a series of ultraviolet and deep-blue CPL materials was developed, successfully integrating high photoluminescence quantum yields with efficient high-level reverse intersystem crossing (hRISC) properties. Efficient ultraviolet and deep-blue CP-OLEDs are created by utilizing these chiral materials as emitters, providing maximum external quantum efficiencies (ηext,maxs) of 6.7% at 398 nm (full-width at half-maximum [FWHM] = 44 nm) and 10.8% at 454 nm (FWHM = 68 nm) with obvious CP-EL. Furthermore, by adopting these chiral materials as sensitizers or functional layers, well-developed achiral multi-resonance thermally activated delayed fluorescence green and yellow emitters are enabled to generate obvious CP-EL with large dissymmetry factors and excellent EL performance (ηexts = 34.5% and 35.3%, FWHM = 42 and 40 nm). These results demonstrate that the developed new ultraviolet and deep-blue chiral materials can be used not only as emitters for ultraviolet and deep-blue CP-OLEDs, but also as sensitizers and functional layers to furnish a simple and universal way of achieving efficient narrow-spectrum CP-OLEDs with achiral emitters.</p
Covalent organic framework with second near-infrared aggregation-induced emission for boosted tumor multimodal phototheranostics
No full textCovalent organic frameworks (COFs) are promising materials for cancer phototherapy, however, achieving precise multimodal theranostics in deep tissues remains challenging due to their typically short emission wavelengths. To address this limitation, we developed for the first time a COF with second near-infrared aggregation-induced emission (NIR-II AIE) characteristics, termed COF-AIE, by noncovalently incorporating the NIR-II AIE-active molecule BTT-COOH into TB-COF. COF-AIE exhibits an emission peak at ∼1000 nm, demonstrating exceptional NIR-II AIE properties. Importantly, the confinement of BTT-COOH within the COF framework affords the enhanced NIR-II fluorescence intensity compared to free BTT-COOH. Beyond that, COF-AIE retains the excellent photothermal conversion efficiency of BTT-COOH, while its high porosity promotes oxygen diffusion, boosting reactive oxygen species generation. These synergistic enhancements were further corroborated by density functional theory calculations. By integrating multiple optimized properties, COF-AIE achieves outstanding performance in NIR-II fluorescence imaging-navigated photothermal-photodynamic synergistic therapy towards tumor.</p
Design and Analysis of a Hinge Splitting Method for Thick Flat Foldable Origami Tessellations
No full textOrigami-inspired engineering designs encounter a fundamental issue of non-negligible material thickness, which introduces structural interference during the development processes. To address this issue, this study builds upon the established hinge-splitting methods and proposes a novel methodology that splits hinges into pairs of mechanical joints and incorporates supplementary panels to connect adjacent main panels. Unlike membrane or flexible joints, the use of mechanical joints enhances motion accuracy and extends the operational lifespan of the mechanism, broadening its potential for engineering applications. First, we present a detailed methodology for structural design, providing a comprehensive solution for interference avoidance. Second, we define and analyze the kinematics of a thickened degree-4 vertex unit (TD4V), identify the structural interference arising from the double-hinge method, and propose a tailored structural design to resolve this issue. Finally, we introduce an algorithm for implementing a width-adding technique to split hinges in origami tessellations, supported by case studies that illustrate the algorithm's effectiveness. Our work advances the practical application of origami-inspired structures in fields such as aerospace, architecture, and robotics.</p
Unravelling the molecular fingerprint of plastic accumulation on blue carbon sediment
No full textA disproportionately large accumulation of plastic waste has turned blue carbon ecosystems (mangrove forests, tidal marshes, and seagrass meadows) into hotspots of plastic pollution. Although our understanding of the effects of plastics on coastal ecosystems has advanced considerably, the underlying effects on blue carbon sediment biogeochemistry are yet to be assessed. Here, we examined the potential organic matter turnover and degradability of conventional plastics, i.e. polyethylene terephthalate (PET) and polypropylene (PP) and biodegradable plastic, i.e. polylactic acid (PLA) in a controlled microcosm experiment containing mangrove sediments. We measured dissolved organic carbon (DOC) leaching, changes in sediment dissolved organic matter (DOM), and the simultaneous greenhouse gas emissions caused by plastics. After 90 days of incubation, low molecular weight PP was visibly degraded on the surface, but high molecular weight PET and PLA were not. The degradation of PP and granular structure of PET led to higher DOC content and number of DOM molecules in sediment compared to that of PLA. Initially, PET contributed higher bio-labile compounds to the sediment, but after 90 days of incubation biologically recalcitrant compounds were more prominent. Despite contributing less DOC and DOM, sediment with PLA emitted higher CO2, suggesting that PLA may accelerate the degradation of native organic matter, whereas PP reduced the cumulative emission. In short, both conventional and biodegradable plastics affect sediment biogeochemistry by altering DOC content, DOM composition and turnover. This study provides new insights into the signature of different plastics in blue carbon sediment dynamics.</p
Rate dependence in granular matter with application to tunable metamaterials
No full textJammed granular matter exhibits diverse rate-dependent behaviors that govern its mechanical response. We examine jammed assemblies under confining pressure and identify rate-strengthening, rate-independent, and rate-softening behaviors. Remarkably, we discover a pronounced rate-softening effect in rice particles, where increasing loading rate significantly reduces yield stress due to a sharp drop in surface friction, weakening the granular force-chain network. Through systematic experiments and simulations, we reveal that this behavior is tunable by modifying surface friction or confining pressure, unlocking design possibilities. To demonstrate its functional significance, we develop a bi-beam metamaterial that switches buckling direction with loading speed; extending to a dual-unit design yields a programmable response—contact reinforcement at slow rates, separation at fast—amplifying the rate dependence. These findings establish a new paradigm for tunable metamaterials, harnessing rate dependence of granular matter to create adaptive and programmable mechanical systems with potential applications in soft robotics, energy absorption, and wearable protection.</p
A 3D multiphase SPH framework for modelling soil-water interaction in rainfall-landslide-tsunami cascades
No full textMulti-hazard cascades, in which multiple hazards interact through one or more natural processes, are an increasing concern worldwide. Among them, landslide-tsunami events represent one of the most significant cascading hazards due to their destructive potential. Computational modelling of the entire cascading process, from the initial triggering to the amplification of risks as the events evolve, is critical, and has attracted growing interest within the research community. This paper presents a novel three-dimensional multiphase smoothed particle hydrodynamics (SPH) model to address this challenge. The proposed framework provides a unified approach for simulating coupled soil-water interactions, including pore water flow in saturated and unsaturated soils, soil deformation, and the dynamic interaction between landslide masses and external water bodies. Key innovations and contributions of the model include: (1) the introduction of a numerical density concept to mitigate issues arising from discontinuities in physical density at interphase interfaces; (2) the integration of u–w–p formulation of Biot's theory into the multiphase model to accurately capture coupled flow–deformation behaviour in saturated and unsaturated soils; (3) an extension of the δ-SPH scheme to ensure a smooth and stable pressure field for both external water and internal pore water; (4) robust treatment for solid and hydraulic boundaries specific to coupled soil-water problems; (5) implementation within a CUDA-based, GPU-accelerated framework for large-scale 3D applications. The model is rigorously validated against a series of benchmark tests and finally applied to the 3D simulation of a rainfall–landslide–tsunami cascade. The results demonstrate that the proposed framework effectively captures the entire hazard cascading process, from rainfall infiltration, landslide initiation and motion, and tsunami generation and propagation, to the final impacts such as overtopping and flooding. This represents a significant advance in computational modelling of geophysical multi-hazard cascades.</p
Maximizing Decision-making Time Overhead-aware Computation Rate in Wireless Powered Mobile Edge Computing
No full textWireless powered mobile edge computing (WPMEC) has emerged as a promising paradigm to mitigate the energy and computation limitations of small-scale Internet-of-Things (IoT) devices. Typical WPMEC operates in a discrete-time manner: at the beginning of each time block, a resource optimization algorithm determines system configuration parameters, and the remainder time block is exploited to perform computation and communication tasks based on optimized settings. Although various decision-making algorithms have been proposed for WPMECs, the associated computational time overhead is often overlooked in existing studies. However, the execution time of decision-making algorithms occupies a non-negligible portion of time in practice, particularly in fast fading channels. In view of this, we define a unified performance evaluation metric termed decision-making time overhead-aware computation rate (DTO-ComRate), which jointly accounts for decision accuracy and algorithmic complexity. Then, we first formulate an optimization problem to maximize the weighted sum DTO-ComRate by jointly optimizing offloading and channel resources. To efficiently address this problem, we further propose a candidate solution set (CSS)-guided deep learning (CSS-DL) algorithm, in which linear relaxation is leveraged to construct the CSS, and a deep neural network (DNN) is trained to assign channel resources in an online self-learning manner. Experiments show that CSS-DL significantly outperforms baseline algorithms and maintains robust performance as the number of IoT devices increases, demonstrating its scalability to large-scale wireless systems.</p
Eduard von Hartmann, Pessimism, and the Europeanization of Buddhism
No full textEduard von Hartmann was one of the most influential public philosophers of his era, known primarily through his Philosophy of the Unconscious. A conservative nationalist in politics, he positioned himself as a cultural and religious reformer and modernist advocate of a “religion of the future” of self-redemption (autosoterism), one that reconciled pessimism and a panpneumatic impersonal unconscious with rationality and individual responsibility. This paper traces how Buddhism served as a primary albeit imperfect exemplar in his thought, how his ethical and symbolic interpretative strategy, based on the unconscious, drew him into proximity and conflict with esoteric spiritist discourses, and how this context informed his Daodejing interpretation. German Idealism disclosed the unity of reason, will, and nature, while Buddhist teachings demonstrated the world’s fundamentally contradictory and illusory character through nothingness (emptiness), nirvāṇa, and objective illusionism and phenomenalism. Hartmann’s secularized moral and symbolic adaptation of Buddhism entailed a resigned yet heroic embrace of suffering life rather than what he deemed ascetic and quietist acquiescence. His hermeneutics reveal his modernizing vision of Buddhism as an exemplary model (if suitably reformed to ac-centuate a heroic response to suffering and karma) for the future.</p
Comparability between AI and human cognition and its role in psychological research and AI ethics
No full textWith the advances in AI technology, comparison studies between humans and AI can not only enhance our understanding of information processing mechanisms underlying human cognition but also facilitate our understanding of AI systems' behaviour and interactions with humans. In particular, explainable AI (XAI) methods, including both computational and experimental methods, can be used to reveal the mechanisms underlying AI's behaviour and its interactions with humans. This information can be used (1) as computational models to study human behaviour, (2) for updating users' beliefs about AI during the interactions, and (3) for evaluation purposes to examine potential ethical issues associated with AI adoption. Different AI systems may require different XAI methods to accurately reveal their underlying mechanisms to facilitate the comparisons with humans. Thus, an important future research direction is to develop task-specific XAI methods through interdisciplinary approaches across psychology and AI to benefit both psychological research and the development of ethical AI.</p
Efficient Multiexciton Energy Transfer from Quantum Dots to Molecular Triplets
No full textColloidal quantum dots (QDs) have emerged as a class of important materials for light harvesting and conversion applications. Unlike most molecular systems, each QD can accommodate multiple excitons, but these multiexcitons often decay rapidly through nonradiative Auger recombination, strongly limiting their utilization efficiency. Previous studies have adopted molecular acceptors to extract charges from multiexcitons of QDs, but the resulting charge-separated states are eventually lost via recombination. In recent years, triplet energy transfer from QDs to molecules have been established as an effective means for long-time storage of exciton energy for a variety of photochemical applications. To date, however, multiexciton energy transfer from QDs to molecular triplets has never been demonstrated. Here we report efficient energy transfer from the multiexciton states of Cd, Pb-free ZnSe-based QDs to their surface-anchored aggregation-induced-emission (AIE) molecules achieved through stepwise charge-transfer. The key is to first dissociate multiexcitons through rapid interfacial electron transfer, with a remarkable efficiency of 96% even for the average exciton number per QD (⟨N⟩) as large as 5.2. The subsequent hole transfer step then populates multiple AIE molecules to their triplet states, which are utilized for singlet-oxygen generation and organic photocatalysis. Crucially, both the AIE triplet yield and the singlet-oxygen yield increase almost linearly with ⟨N⟩ until ⟨N⟩ reaches 6, indicating that the triplet energy transfer efficiency of multiexcitons is just as efficient as that of single-excitons.</p