Seismic full waveform inversion (FWI) is a powerful technology to obtain high-precision and high-resolution images of subsurface structures. However, FWI is a data-intensive algorithm that needs to ...read extensive seismic data from disks, which significantly affects its performance. We proposed a portable parallel framework to improve FWI by overlapping data input and computation (ODIC). The framework is based on POSIX threads (Pthreads), which is a standard thread API library and can create a parent thread and a child thread in the FWI process. The former is used to perform computation and the latter to read data from disks, both running simultaneously. This framework has two attractive features. First, it is broadly applicable; it can run on almost any computer from a laptop to a supercomputer. Second, it is easy to implement; it can be readily applied to existing FWI programs. A 3D FWI example shows that the framework speeds up FWI considerably.
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Natural materials have always attracted intensive attention from multidisciplinary scientists all over the world. In fact, the ingenious and reasonable synthetic strategies of the ...limited components can always make natural materials achieve a superior performance that is far beyond their own. Meanwhile, the local properties can determine the overall performance through regulating multiple characteristics, including structure, composition, and interface. Living organisms can inspire the fabrication of artificial materials, which provides a clear vision for advanced materials research. Therefore, inspired by this strategy, biomimetic structural materials are used to meet the strict and even extreme requirements of engineering materials. In this review, we mainly clarify the difference of local properties in natural materials and explain how living organisms utilize very limited elements and compounds to control the local properties and further realize some specific function to adapt to the specific requirement of the environment. In addition, the manufacturing technologies and strategies common to bio-inspired structural materials are summarized. Finally, a summary and prospects on the limitations of current techniques and the direction of future developments for the design of novel bio-inspired materials are given.
A translational motion estimation and compensation method is proposed based on the parametric method by multiple stations in the distributed inverse synthetic aperture radar (ISAR) imaging. For ship ...targets with complex motion, the distributed ISAR increases the cross‐range resolution of the image by expanding the observation angle. However, the translation compensation methods by a single station will destroy the correlation between the echoes, which reduces the image quality, and a more accurate joint translation compensation method is required. Multi‐static observation is obtained in the Distributed system, which we can utilise in the parameter estimation: 1) joint Doppler estimation, 2) station angle estimation, and 3) rotation velocity estimation. Based on the above estimations, the velocity vector and the acceleration vector of the target can be obtained, and then the translational motion compensation can be realised parametrically. The algorithm processing chain is presented in this paper. Finally, the numerical simulations with four stations are presented to verify the effectiveness and the robustness of the proposed algorithm.
Cicada wings, covered with arranged nanostructures, were widely studied owing to their high transparency and low reflection. However, limited by technologies, their exquisite surface structures and ...multifunctional features were not inherited and applied by most artificial materials adequately. Here, the excellent optical properties of the cicada wing were investigated in detail experimentally and theoretically. Besides, a flexible self-cleaning broadband antireflective film inspired by the cicada wing has been successfully fabricated by a well-designed biological template method and sol–gel process. The cicada wing (Megapomponia intermedia) was selected as the original template directly, and a SiO2 negative replica was obtained by a sol–gel process. Then, chemical corrosion was used to remove the original template, retaining the pure negative replica. Subsequently, the polymethyl methacrylate (PMMA) positive replica could be rebuilt after another sol–gel process. Compared with a flat PMMA film, the average reflectivity of the structured PMMA film over the visible region was reduced from 10 to 2%. Besides, the bio-inspired film with a thickness of 0.18 mm exhibited satisfactory comprehensive performances with low reflectance (≤2%) in most of the visible region, as well as superhydrophobic property and perfect flexibility. Our results offered a quick and simple method to rebuild the nanostructured functional materials, promoting the practical applications of the bionic nanostructured materials. Meanwhile, the modified biomimetic fabrication method provides a solution for rebuilding exquisite biological materials and designing multifunctional surfaces. Moreover, the multifunctional antireflective film with wider universality will exhibit an enormous potential application value in optical communications, photoelectric devices, flexible display screens, and antidazzle glasses.
A mirror twin-domain boundary (MTB) in monolayer MoSe2 represents a (quasi) one-dimensional metallic system. Its electronic properties, particularly the low-energy excitations in the so-called ...4|4P-type MTB, have drawn considerable research attention. Reports of quantum well states, charge density waves, and the Tomonaga–Luttinger liquid (TLL) have all been made. Here, by controlling the lengths of the MTBs and employing different substrates, we reveal by low-temperature scanning tunneling microscopy/spectroscopy, Friedel oscillations and quantum confinement effects causing the charge density modulations along the defect. The results are inconsistent with charge density waves. Interestingly, for graphene-supported samples, TLL in the MTBs is suggested, whereas that grown on gold, an ordinary Fermi liquid, is indicated.
Mirror twin boundary (MTB) brings unique one-dimensional (1D) physics and properties into two-dimensional (2D) transition metal dichalcogenides (TMDCs), but they were rarely observed in non-Mo-based ...TMDCs. Herein, by post-growth Nb doping, high density 4|4E-W and 4|4P-Se mirror twin boundaries (MTBs) were introduced into molecular beam epitaxy (MBE) grown WSe
2
monolayers. Of them, 4|4E-W MTB with a novel structure was discovered experimentally for the first time, while 4|4P-Se MTBs present a random permutations of W and Nb, forming a 1D alloy system. Comparison between the doped and non-doped WSe
2
confirmed that Nb dopants are essential for MTB formation. Furthermore, quantitative statistics reveal the areal density of MTBs is directly proportional to the concentration of Nb dopants. To unravel the injection pathway of Nb dopants, first-principles calculations about a set of formation energies for excess Nb atoms with different configurations were conducted, based on which a model explaining the origin of MTBs introduced by excess metal was built. We conclude that the formation of MTBs is mainly driven by the collective evolution of excess Nb atoms introduced into the lattice of host WSe
2
crystal and subsequent displacement of metal atoms (W or Nb). This study provides a novel way to tailor the MTBs in 2D TMDC materials via proper metal doping and presents new opportunities for exploring the intriguing properties.
Epithelial-mesenchymal transition (EMT) is a developmental biological process that is hijacked during tumor progression. Cadherin switching, which disrupts adherens junctions and alters ...cadherin-associated signaling pathways, is common during EMT. In many tumors, substantial extracellular matrix (ECM) is deposited. Collagen is the most abundant ECM constituent and it mediates specific signaling pathways by binding to integrins and discoidin domain receptors (DDRs). The interaction of the collagen receptors results in activation of signaling pathways that promote tumor progression including an induction of the cadherin switching. DDR inhibitors have demonstrated anticancer therapeutic efficacy preclinically by inhibiting the collagen signaling. Understanding how collagen signaling impacts cellular processes including EMT and cadherin switching is of great interest especially given the strong interest in stromal targeted therapies for desmoplastic cancers.
•Cadherin switching during tumor progression disrupts adherens junctions and alters cadherin-associated signaling pathways.•Many tumors are characterized by substantial collagen deposition which activates integrins and DDRs.•The activation of integrins and DDRs by collagen leads to cadherin switching through specific signaling pathways.•Inhibition of DDRs with small molecules have anticancer therapeutic efficacy.
Water soluble N, S-doped carbon dots (N, S-CDs) with orange emission were synthesized from basic fuchsin and sulfosalicylic acid by the typical hydrothermal route. Based on the inner filter effect ...(IFE), the prepared N, S-CDs can be innovatively developed as an effective “signal-off” multifunctional sensing platform for sensitive determination of tetracycline antibiotics (for example, chlortetracycline (CTC)) and quercetin. The proposed sensor was utilized to realize the determination of CTC in water and milk samples and quercetin in beer sample (λex = 375 nm, λem = 605 nm) with satisfactory recoveries and relative standard deviations (RSD). The linear range and detection limit (LOD) of CTC is 1.24–165 μM and 32.36 nM, respectively. For quercetin, the linear ranges are 0.98–34 μM and 34–165 μΜ, and the LOD is 6.87 nM (3σ/m). By virtue of the good biocompatibility and long-wavelength emission, N, S-CDs were also used in the imaging of oocystis cells and yeast cells, which demonstrated promising applicability for bio-imaging and sensing.
Graphical abstract
In this paper, N, S-doped carbon dots (N, S-CDs) with orange emission (λem = 605 nm) were synthesized from basic fuchsin and sulfosalicylic acid. Based on the inner filter effect (IFE), the prepared N, S-CDs can be innovatively developed as an effective “signal-off” multifunctional sensing platform for the sensing of tetracycline antibiotics (for example: chlortetracycline (CTC)) and quercetin. The sensor has been successfully applied to the determination of CTC in water and milk samples and quercetin in beer sample (λex = 375 nm, λem = 605 nm). The linear range and detection limit (LOD) of CTC is 1.24-165 μM and 32.36 nM respectively. For quercetin, the linear ranges are 0.98-34 μM and 34-165 μΜ, and the LOD is 6.87 nM (3σ/m). In addition, due to the characteristics of good biocompatibility and long-wavelength emission, the N, S-CDs were also used in the imaging of oocystis cells and yeast cells, which demonstrated promising applicability for bioimaging and sensing.
Solid particle erosion is a common phenomenon in engineering fields, such as manufacturing, energy, military and aviation. However, with the rising industrial requirements, the development of ...anti-solid particle erosion materials remains a great challenge. After billions of years of evolution, several natural materials exhibit unique and exceptional solid particle erosion resistance. These materials achieved the same excellent solid particle erosion resistance performance through diversified strategies. This resistance arises from their micro/nanoscale surface structure and interface material properties, which provide inspiration for novel multiple solutions to solid particle erosion. Here, this review first summarizes the recent significant process in the research of natural anti-solid particle erosion materials and their general design principles. According to these principles, several erosion-resistant structures are available. Combined with advanced micro/nanomanufacturing technologies, several artificial anti-solid particle erosion materials have been obtained. Then, the potential applications of anti-solid particle erosion materials are prospected. Finally, the remaining challenges and promising breakthroughs regarding anti-solid particle erosion materials are briefly discussed.
Confining interacting particles in one-dimension (1D) changes the electronic behavior of the system fundamentally, which has been studied extensively in the past. Examples of 1D metallic systems ...include carbon nanotubes, quasi-1D organic conductors, metal chains, and domain boundary defects in monolayer thick transition-metal dichalcogenides such as MoSe2. Here single and bundles of Mo6Se6 nanowires were fabricated through annealing a MoSe2 monolayer grown by molecular-beam epitaxy on graphene. Conversion from two-dimensional (2D) MoSe2 film to 1D Mo6Se6 nanowire is reversible. Mo6Se6 nanowires form preferentially at the Se-terminated zigzag edges of MoSe2 and stitch to it via two distinct atomic configurations. The Mo6Se6 wire is metallic and its length is tunable, which represents one of few 1D systems that exhibit properties pertinent to quantum confined Tomonaga–Luttinger liquid, as evidenced by scanning tunneling microscopic and spectroscopic studies.
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