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Understanding precipitation-vegetation interaction is of great importance to implementing adaptation and mitigation measures for terrestrial ecosystems. Many studies have explored the spatial pattern of precipitation-vegetation correlation along the precipitation amount gradient. While the impacts of other precipitation characteristics remain poorly understood. Here, we provided a comprehensive investigation of spatiotemporal patterns of vegetation response to precipitation anomalies in China, using satellite-derived vegetation index and multi-source climate datasets for the years 1982–2015. Subsequently, we attempted to examine in detail what specific factors, climatic or biogeographic, are responsible for spatiotemporal patterns of precipitation-vegetation relationship. Results show that vegetation in Inner Mongolia Plateau is strongly affected by precipitation anomalies. Vegetation has a 1–2 month lag response to precipitation anomalies and is significantly correlated with 2–6 month cumulative precipitation anomalies. Seasonal differences of vegetation response are also remarkable. Moreover, the largest NDVI-precipitation correlation appears in areas with 150–500 mm of mean annual precipitation, 0.075–0.275 of fraction of precipitation days, and 19–23 of precipitation concentration index. More locally, the spatial distribution of NDVI-precipitation correlations is closely related to the vegetation type and elevation. The results can provide technical basis and beneficial reference to water resource and ecological management strategies in China for associated policymakers and stakeholders.

Although elevated atmospheric CO 2 concentration (eCO 2 ) has substantial indirect effects on vegetation carbon uptake via associated climate change, their dynamics remain unclear. Here we investigate how the impacts of eCO 2 -driven climate change on growing-season gross primary production have changed globally during 1982–2014, using satellite observations and Earth system models, and evaluate their evolution until the year 2100. We show that the initial positive effect of eCO 2 -induced climate change on vegetation carbon uptake has declined recently, shifting to negative in the early 21st century. Such emerging pattern appears prominent in high latitudes and occurs in combination with a decrease of direct CO 2 physiological effect, ultimately resulting in a sharp reduction of the current growth benefits induced by climate warming and CO 2 fertilization. Such weakening of the indirect CO 2 effect can be partially attributed to the widespread land drying, and it is expected to be further exacerbated under global warming. It is unclear how indirect CO 2 effect – via associated climate change – on vegetation carbon uptake changes globally. Here, the authors show that such initial positive effect has declined recently, shifting to negative in the early 21st century.

Vegetation greening in China is known to cool the land surface by altering the energy budget through biophysical processes. However, its mitigation effects on extreme temperatures and the underlying mechanisms remain poorly understood. Here, we use coupled land‐atmosphere model simulations to quantitatively assess the effects of vegetation greening on summer mean and extreme land surface temperatures in Eastern China over the 2003–2018 period. We show that the modeled cooling effect on summer mean land surface temperature is more pronounced in arid Northeastern China than in humid Southeastern China, consistent with satellite‐derived temperature responses. In contrast, for extreme hot temperatures, the spatial pattern of the cooling effect reverses, largely because high temperatures accompanied by strong radiation can alleviate energy constraints on evaporative cooling in Southeastern China. These findings underscore the potential role of vegetation greening in mitigating extreme hot extremes, with important implications for local land‐based mitigation and adaptation strategies.

Two-dimensional (2D) materials have been considered promising candidates for future low power-dissipation and reconfigurable integrated circuit applications. However, 2D transistors with intrinsic ambipolar transport polarity are usually affected by large off-state leakage currents and small on/off ratios. Here, we report the realization of a reconfigurable Schottky junction field-effect transistor (SJFET) in an asymmetric van der Waals contact geometry, showing a balanced and switchable n- and p-unipolarity with the I ds on/off ratio kept >10 6 . Meanwhile, the static leakage power consumption was suppressed to 10 −5 nW. The SJFET worked as a reversible Schottky rectifier with an ideality factor of ~1.0 and a tuned rectifying ratio from 3 × 10 6 to 2.5 × 10 −6 . This empowered the SJFET with a reconfigurable photovoltaic performance in which the sign of the open-circuit voltage and photo-responsivity were substantially switched. This polarity-reversible SJFET paves an alternative way to develop reconfigurable 2D devices for low-power-consumption photovoltaic logic circuits. Here, the authors report the realization of WSe 2 Schottky junction field-effect transistors with asymmetric multi-layer graphene and WTe 2 van der Waals contacts, enabling reconfigurable polarity, low off-state currents, near-ideal rectifying behaviour and bipolar photovoltaic response.

Terahertz modulators with high tunability of both intensity and phase are essential for effective control of electromagnetic properties. Due to the underlying physics behind existing approaches there is still a lack of broadband devices able to achieve deep modulation. Here, we demonstrate the effect of tunable Brewster angle controlled by graphene, and develop a highly-tunable solid-state graphene/quartz modulator based on this mechanism. The Brewster angle of the device can be tuned by varying the conductivity of the graphene through an electrical gate. In this way, we achieve near perfect intensity modulation with spectrally flat modulation depth of 99.3 to 99.9 percent and phase tunability of up to 140 degree in the frequency range from 0.5 to 1.6 THz. Different from using electromagnetic resonance effects (for example, metamaterials), this principle ensures that our device can operate in ultra-broadband. Thus it is an effective principle for terahertz modulation. Low-dimensional materials show promise for applications in imaging, spectroscopy and ultra-broadband communications. Here, the authors report an effect of Brewster angle control at graphene-quartz interface for applications in terahertz modulation over a broadband range from 0.5 to 1.6 THz.

Interlayer excitons in van der Waals (vdW) heterostructures (HSs) have garnered significant attention due to their unique properties, including prolonged lifetimes and long-range transport. While extensive studies have been conducted on interlayer excitons in HSs composed of different monolayers, research on HSs formed by multilayer constituents remains limited, particularly regarding dipole moments, which play a crucial role in light-matter interactions. In this study, we investigate the dipole moments of interlayer excitons in multilayer WS₂ and InSe HSs using the quantum-confined Stark effect. Our findings reveal that the dipole moment increases monotonically with the number of layers in InSe or WS₂, reaching a maximum of 3.18 e nm, which is the largest value reported to date. Consequently, the dipole-dipole interaction is enhanced with the increasing layer number, as demonstrated by excitation power-dependent measurements. Ab initio calculations further support our experimental results, indicating the delocalization of the excitonic wave function with increasing layer thickness. Our findings introduce a novel layer-engineered mechanism for tuning the dipole moments of interlayer excitons in vdW heterostructures, paving the way for manipulating many-body interactions in low-dimensional quantum systems. This work presents a layer-engineering mechanism that enables the continuous tuning of the dipole moment of interlayer excitons in layered materials, resulting in enhanced dipole moment and enhanced dipole-dipole interactions as the number of layers increases.

Hepatic encephalopathy (HE) is a neurological disorder that occurs in patients with liver insufficiency. However, its pathogenesis has not been fully elucidated. Pharmacotherapy is the main therapeutic option for HE. It targets the pathogenesis of HE by reducing ammonia levels, improving neurotransmitter signal transduction, and modulating intestinal microbiota. Compared to healthy individuals, the intestinal microbiota of patients with liver disease is significantly different and is associated with the occurrence of HE. Moreover, intestinal microbiota is closely associated with multiple links in the pathogenesis of HE, including the theory of ammonia intoxication, bile acid circulation, GABA-ergic tone hypothesis, and neuroinflammation, which contribute to cognitive and motor disorders in patients. Restoring the homeostasis of intestinal bacteria or providing specific probiotics has significant effects on neurological disorders in HE. Therefore, this review aims at elucidating the potential microbial mechanisms and metabolic effects in the progression of HE through the gut–brain axis and its potential role as a therapeutic target in HE.

Transition metal dichalcogenides (TMDCs) have recently attracted growing attention in the fields of dielectric nanophotonics because of their high refractive index and excitonic resonances. Despite the recent realizations of Mie resonances by patterning exfoliated TMDC flakes, it is still challenging to achieve large-scale TMDC-based photonic structures with a controllable thickness. Here, we report a bulk MoS 2 metaphotonic platform realized by a chemical vapor deposition (CVD) bottom-up method, supporting both pronounced dielectric optical modes and self-coupled polaritons. Magnetic surface lattice resonances (M-SLRs) and their energy-momentum dispersions are demonstrated in 1D MoS 2 gratings. Anticrossing behaviors with Rabi splitting up to 170 meV are observed when the M-SLRs are hybridized with the excitons in multilayer MoS 2 . In addition, distinct Mie modes and anapole-exciton polaritons are also experimentally demonstrated in 2D MoS 2 disk arrays. We believe that the CVD bottom-up method would open up many possibilities to achieve large-scale TMDC-based photonic devices and enrich the toolbox of engineering exciton-photon interactions in TMDCs. Transition metal dichalcogenides (TMDCs) are interesting for nanophotonic applications due to their high refractive index and excitonic properties. Here, the authors report a scalable bottom-up fabrication method to realize arrays of TMDC metastructures showing dielectric optical modes and self-coupled exciton-polaritons.

This paper proposes a two-phase evolutionary algorithm framework for solving multi-objective optimization problems (MOPs), which allows different users to flexibly handle MOPs with different existing algorithms. In the first phase, a specific multi-objective evolutionary algorithm (MOEA) with a smaller population size is adopted to fast obtain a population converging to the true Pareto front. Then, in the second phase, a simple environmental selection mechanism based on a measure function and a well-designed crowdedness function is used to promote the uniformity of population in the objective space. Based on the proposed framework, we form four instantiations by embedding four distinct MOEAs into the first phase of the proposed framework. In the experimental study, different experiments are conducted on a variety of well-known benchmark problems from 3 to 10 objectives, and experimental results demonstrate the effect of the proposed framework. Furthermore, compared with several state-of-the-art multi-objective evolutionary algorithms, the four instantiations of the proposed framework have better performance and can obtain well-distributed solution sets. In short, the proposed framework has the strong ability to promote the performance of existing algorithms.

Hybrid graphene photoconductor/phototransistor has achieved giant photoresponsivity, but its response speed dramatically degrades as the expense due to the long lifetime of trapped interfacial carriers. In this work, by intercalating a large-area atomically thin MoS 2 film into a hybrid graphene photoconductor, we have developed a prototype tunneling photoconductor, which exhibits a record-fast response (rising time ~17 ns) and a high responsivity (~3 × 10 4  A/W at 635 nm illumination with 16.8 nW power) across the broad spectral range. We demonstrate that the photo-excited carriers generated in silicon are transferred into graphene through a tunneling process rather than carrier drift. The atomically thin MoS 2 film not only serves as tunneling layer but also passivates surface states, which in combination delivers a superior response speed (~3 orders of magnitude improved than a device without MoS 2 layer), while the responsivity remains high. This intriguing tunneling photoconductor integrates both fast response and high responsivity and thus has significant potential in practical applications of optoelectronic devices. Optoelectronics: tunneling photodetectors break the trade-off between speed and responsivity Graphene-based photodetectors with an embedded MoS 2 tunnel layer show remarkable responsivities, whilst still retaining fast response times. A team led by Jian-Bin Xu at the Chinese University of Hong Kong tackled the trade-off between speed and responsivity by intercalating two-dimensional MoS 2 into a graphene photodetector. This results in the formation of a hybrid tunneling photoconductor, where silicon plays the role of optically active layer, whereas MoS 2 serves as tunneling layer. The insertion of ultra-thin MoS 2 enables fast transfer of the photo-excited carriers in silicon towards graphene, whilst also passivating surface states. This approach effectively bypasses the speed limitations caused by the long lifetime of trapped interfacial carriers, resulting in a remarkable 17 ns response time and a high, broadband responsivity up to 3 × 10 4  A/W.