10 research outputs found

    Designing an exploration scale OBN: Acquisition design for subsalt imaging and velocity determination

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    Direct wave arrivals are the most robust signals to determine velocity and consequently they have been used for almost a century in hydrocarbon exploration. The reason is simple as the arrival time is explicitly available. In order to acquire these direct arrivals in a seismic experimental setting it is necessary that these waves turns back to the surface after having been sent into the Earth. As is well known it is possible to turn waves back up if they encounter faster propagation velocities than have been previously experienced. Using these simple concepts we show how it is possible to design a seismic acquisition to measure subsalt velocities when the salt cover is very thick and potentially not homogeneous. Until now (in marine seismic surveying) the physical limitations of the Earth have meant that use of direct wave arrivals have been restricted to relatively shallow depths of investigation, linked to streamer length. In this paper we describe how a new and novel application of node technology has been combined with a well established physical phenomena to support the acquisition of a world first exploration-scale Ocean Bottom Node (OBN) survey

    End-to-end deep learning model for underground utilities localization using GPR

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    Underground utilities (UUs) are key infrastructures in urban life operations. The localization of UUs is vital to governments and residents in terms of asset management, utility planning, and construction safety. UUs localization has been investigated extensively via the automatic interpretation of ground-penetrating radar B-scan images. However, conventional image processing methods are time consuming and susceptible to noise. Deep learning-based methods cannot optimize parameters globally because of their box-fitting mode, which requires the separation of a task into region detection and hyperbola fitting problems. Thus, the accuracy and robustness of the localization task are reduced. Hence, an end-to-end deep learning model based on a key point–regression mode is proposed and validated in this study. Experimental results show that the proposed method outperforms the current mainstream models in terms of localization accuracy (97.01%), inference speed (125 fps), and robustness on the same platform (NVDIA RTX 3090 GPU)

    Three-dimensional Nitrogen-Doped Graphene Supported Molybdenum Disulfide Nanoparticles as an Advanced Catalyst for Hydrogen Evolution Reaction.

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    An efficient three-dimensional (3D) hybrid material of nitrogen-doped graphene sheets (N-RGO) supporting molybdenum disulfide (MoS(2)) nanoparticles with high-performance electrocatalytic activity for hydrogen evolution reaction (HER) is fabricated by using a facile hydrothermal route. Comprehensive microscopic and spectroscopic characterizations confirm the resulting hybrid material possesses a 3D crumpled few-layered graphene network structure decorated with MoS(2) nanoparticles. Electrochemical characterization analysis reveals that the resulting hybrid material exhibits efficient electrocatalytic activity toward HER under acidic conditions with a low onset potential of 112 mV and a small Tafel slope of 44 mV per decade. The enhanced mechanism of electrocatalytic activity has been investigated in detail by controlling the elemental composition, electrical conductance and surface morphology of the 3D hybrid as well as Density Functional Theory (DFT) calculations. This demonstrates that the abundance of exposed active sulfur edge sites in the MoS(2) and nitrogen active functional moieties in N-RGO are synergistically responsible for the catalytic activity, whilst the distinguished and coherent interface in MoS(2)/N-RGO facilitates the electron transfer during electrocatalysis. Our study gives insights into the physical/chemical mechanism of enhanced HER performance in MoS(2)/N-RGO hybrids and illustrates how to design and construct a 3D hybrid to maximize the catalytic efficiency

    Enhancing the strength and sensitization resistance of 5xxx alloys via nanoscale clustering induced by room-temperature cyclic plasticity

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    Non-heat-treatable 5xxx Al alloys exhibit good corrosion resistance but can be susceptible to intergranular corrosion in service. This study applies a cyclic strengthening method to the AA5083 alloy, resulting in a significant increase in yield strength (∼300 MPa) and tensile strength (∼385 MPa) due to the formation of Mg-Al solute clusters confirmed by scanning transmission electron microscopy and atom probe tomography. After a two-month sensitization treatment at 70 °C, the clusters delay the formation of Mg-rich precipitates at grain boundaries, enhancing the resistance to sensitization. This new approach strengthens Al-Mg alloys and offers potential for manipulating the corrosion resistance and sensitization susceptibility

    Supplementary - Metabonomic analysis of toxic action of long-term low-level exposure to acrylamide in rat serum

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    <p>Supplementary for Metabonomic analysis of toxic action of long-term low-level exposure to acrylamide in rat serum by C Cao, H Shi, M Zhang, L Bo, L Hu, S Li, S Chen, S Jia, YJ Liu, YL Liu, X Zhao and L Zhang in Human & Experimental Toxicology</p

    A facile approach to tailor electrocatalytic properties of MnO2 through tuning phase transition, surface morphology and band structure

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    The structural and electronic properties of MnO2 based electrocatalysts are key factors determining their electrochemical performance. To date, it is still challenging to synergistically tune the crystal structure, morphology, and electronic band (i.e., band gap and band alignments) of MnO2 through facile synthesis approaches. This study has reported a one-step hydrothermal method to synthesize a prototypical MnO2 electrocatalyst with optimized structural and electrochemical properties. By simply adjusting the hydrothermal time, the phase transition from polymorphic δ to α can be induced in MnO2. The obtained nanowires on nanosheets structure grown in-situ on nickel foam provides a large surface area, great accessible active sites, and good mass/charge transfer efficiency. Further investigation through first-principles calculations reveals that compared to δ-MnO2, the α-MnO2 polymorph with rich oxygen vacancies has better band-alignment tunability, which is also beneficial for improving the electrochemical performance. The α phase MnO2 exhibits superior catalytic performance for both OER and HER (OER overpotential of 0.45 V at 50 mA cm−2 and HER overpotential of 0.14 V at 50 mA cm−2). The developed synthesis method can be extended to catalyst designs that require precise control of phase and morphology evolution in a wide range of applications

    Arctic introgression and chromatin regulation facilitated rapid Qinghai-Tibet Plateau colonization by an avian predator

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    The Qinghai-Tibet Plateau (QTP), possesses a climate as cold as that of the Arctic, and also presents uniquely low oxygen concentrations and intense ultraviolet (UV) radiation. QTP animals have adapted to these extreme conditions, but whether they obtained genetic variations from the Arctic during cold adaptation, and how genomic mutations in non-coding regions regulate gene expression under hypoxia and intense UV environment, remain largely unknown. Here, we assemble a high-quality saker falcon genome and resequence populations across Eurasia. We identify female-biased hybridization with Arctic gyrfalcons in the last glacial maximum, that endowed eastern sakers with alleles conveying larger body size and changes in fat metabolism, predisposing their QTP cold adaptation. We discover that QTP hypoxia and UV adaptations mainly involve independent changes in non-coding genomic variants. Our study highlights key roles of gene flow from Arctic relatives during QTP hypothermia adaptation, and cis-regulatory elements during hypoxic response and UV protection

    Regulating the phase and optical roperties of mixed‐halide perovskites via hot‐electron engineering

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    The rapid development of mixed‐halide perovskites has established a versatile optoelectronic platform owing to their extraordinary physical properties, but there remain challenges toward achieving highly reliable synthesis and performance, in addition, post‐synthesis approaches for tuning their photoluminescence properties after device fabrication remain limited. In this work, an effective approach is reported to leveraging hot electrons generated from plasmonic nanostructures to regulate the optical properties of perovskites. A plasmonic metasurface composed of Au nanoparticles can effectively tailor both photoluminescence and location‐specific phase segregation of mixed‐halide CsPbI2Br thin films. The ultrafast transient absorption spectroscopy measurements reveal hot electron injection on the timescale of hundreds of femtoseconds. Photocurrent measurements confirm the hot‐electron‐enhanced photon‐carrier conversion, and in addition, gate‐voltage tuning of phase segregation is observed because of correlated carrier injection and halide migration in the perovskite films. Finally, the characteristics of the gate‐modulated light emission are found to conform to a rectified linear unit function, serving as nonlinear electrical‐to‐optical converters in artificial neural networks. Overall, the hot electron engineering approach demonstrated in this work provides effective location‐specific control of the phase and optical properties of halide perovskites, underscoring the potential of plasmonic metasurfaces for advancing perovskite technologies
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