Publications by authors named "Jiajie Qi"

Boron nitride (BN) is today considered one of the most promising materials for many novel applications including bright single photon emission, deep UV optoelectronics, small-sized solid-state neutron detectors, high-performance two-dimensional materials, etc. Recently, AA' stacking a few layers (2-5 layers) of BN films and ABC stacking multilayer (2.2-12 nm) BN films have been successfully synthesized, respectively.

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Entangled photon-pair sources are pivotal in various quantum applications. Miniaturizing the quantum devices to meet the requirement in limited space applications drives the search for ultracompact entangled photon-pair sources. The rise of two-dimensional (2D) semiconductors has been demonstrated as ultracompact entangled photon-pair sources.

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Purpose: Myocardial infarction (MI) is a prevalent cardiovascular disorder affecting individuals worldwide. There is a need to identify more effective therapeutic agents to minimize cardiomyocyte damage and enhance cardioprotection. extract is extensively used to treat neurological disorders and peripheral vascular diseases.

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Among the various two-dimensional (2D) materials, more than 99% of them are noncentrosymmetric. However, since the commonly used substrates are generally centrosymmetric, antiparallel islands are usually inevitable in the growth of noncentrosymmetric 2D materials because of the energetic equivalency of these two kinds of antiparallel islands on centrosymmetric substrates. Therefore, achieving the growth of noncentrosymmetric 2D single crystals has long been a great challenge compared with the centrosymmetric ones like graphene.

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Article Synopsis
  • Researchers discovered significant high odd-order optical nonlinearities in a 2D material called manganese phosphorus triselenide, which is a centrosymmetric correlated van der Waals insulator.
  • When subjected to two near-infrared femtosecond lasers, this material produced various four- and six-wave mixing outputs, achieving one of the highest third-order nonlinear susceptibility values recorded for 2D materials.
  • Comparative studies with other nonlinear optical materials showed its superior wave mixing efficiency, suggesting potential advancements in nonlinear light-matter interactions and applications in photonics.
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Rhombohedral-stacked transition-metal dichalcogenides (3R-TMDs), which are distinct from their hexagonal counterparts, exhibit higher carrier mobility, sliding ferroelectricity, and coherently enhanced nonlinear optical responses. However, surface epitaxial growth of large multilayer 3R-TMD single crystals is difficult. We report an interfacial epitaxy methodology for their growth of several compositions, including molybdenum disulfide (MoS), molybdenum diselenide, tungsten disulfide, tungsten diselenide, niobium disulfide, niobium diselenide, and molybdenum sulfoselenide.

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Low-dimensional water transport can be drastically enhanced under atomic-scale confinement. However, its microscopic origin is still under debate. In this work, we directly imaged the atomic structure and transport of two-dimensional water islands on graphene and hexagonal boron nitride surfaces using qPlus-based atomic force microscopy.

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Nanomaterials with a large chiroptical response and high structural stability are desirable for advanced miniaturized optical and optoelectronic applications. One-dimensional (1D) nanotubes are robust crystals with inherent and continuously tunable chiral geometries. However, their chiroptical response is typically weak and hard to control, due to the diverse structures of the coaxial tubes.

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Within the family of two-dimensional dielectrics, rhombohedral boron nitride (rBN) is considerably promising owing to having not only the superior properties of hexagonal boron nitride-including low permittivity and dissipation, strong electrical insulation, good chemical stability, high thermal conductivity and atomic flatness without dangling bonds-but also useful optical nonlinearity and interfacial ferroelectricity originating from the broken in-plane and out-of-plane centrosymmetry. However, the preparation of large-sized single-crystal rBN layers remains a challenge, owing to the requisite unprecedented growth controls to coordinate the lattice orientation of each layer and the sliding vector of every interface. Here we report a facile methodology using bevel-edge epitaxy to prepare centimetre-sized single-crystal rBN layers with exact interlayer ABC stacking on a vicinal nickel surface.

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Optical phase matching involves establishing a proper phase relationship between the fundamental excitation and generated waves to enable efficient optical parametric processes. It is typically achieved through birefringence or periodic polarization. Here, we report that the interlayer twist angle in two-dimensional (2D) materials creates a nonlinear geometric phase that can compensate for the phase mismatch, and the vertical assembly of the 2D layers with a proper twist sequence generates a nontrivial "twist-phase-matching" (twist-PM) regime.

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Nonlinear optical crystals lie at the core of ultrafast laser science and quantum communication technology. The emergence of 2D materials provides a revolutionary potential for nonlinear optical crystals due to their exceptionally high nonlinear coefficients. However, uncontrolled stacking orders generally induce the destructive nonlinear response due to the optical phase deviation in different 2D layers.

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In twisted h-BN/graphene heterostructures, the complex electronic properties of the fast-traveling electron gas in graphene are usually considered to be fully revealed. However, the randomly twisted heterostructures may also have unexpected transition behaviors, which may influence the device performance. Here, we study the twist-angle-dependent coupling effects of h-BN/graphene heterostructures using monochromatic electron energy loss spectroscopy.

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Interfacial atomic configuration and its evolution play critical roles in the structural stability and functionality of mixed zero-dimensional (0D) metal nanoparticles (NPs) and two-dimensional (2D) semiconductors. observation of the interface evolution at atomic resolution is a vital method. Herein, the directional migration and structural evolution of Au NPs on anisotropic ReS were investigated by aberration-corrected transmission electron microscopy.

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Background: Myocardial infarction is a well-established severe consequence of coronary artery disease. However, the lack of effective early biomarkers accounts for the lag time before clinical diagnosis of myocardial infarction. The present study aimed to predict critical genes for the diagnosis of MI by immune infiltration analysis and establish a nomogram.

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The growth of wafer-scale single-crystal two-dimensional transition metal dichalcogenides (TMDs) on insulating substrates is critically important for a variety of high-end applications. Although the epitaxial growth of wafer-scale graphene and hexagonal boron nitride on metal surfaces has been reported, these techniques are not applicable for growing TMDs on insulating substrates because of substantial differences in growth kinetics. Thus, despite great efforts, the direct growth of wafer-scale single-crystal TMDs on insulating substrates is yet to be realized.

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Article Synopsis
  • * Using stepwise regression and geographically weighted regression models, the research analyzes rail transit commuting habits in Wuhan, revealing key statistics such as 60% of students being one-way commuters and 88.6% traveling less than 10 km.
  • * Findings indicate that factors like floor area ratio, bus station density, and transfer stations positively influence commuter flow, while land use mix and road density negatively impact commuting distance, providing insights for improving transit accessibility for students.
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The electrochemical conversion of CO to valuable fuels is a plausible solution to meet the soaring need for renewable energy sources. However, the practical application of this process is limited by its poor selectivity due to scaling relations. Here we introduce the rational design of the monolayer hexagonal boron nitride/copper (h-BN/Cu) interface to circumvent scaling relations and improve the electrosynthesis of CH.

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The production of large single-crystal metal foils with various facet indices has long been a pursuit in materials science owing to their potential applications in crystal epitaxy, catalysis, electronics and thermal engineering. For a given metal, there are only three sets of low-index facets ({100}, {110} and {111}). In comparison, high-index facets are in principle infinite and could afford richer surface structures and properties.

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In the "post-Moore's Law" era, new materials are highly expected to bring next revolutionary technologies in electronics and optoelectronics, wherein 2D materials are considered as very promising candidates beyond bulk materials due to their superiorities of atomic thickness, excellent properties, full components, and the compatibility with the processing technologies of traditional complementary metal-oxide semiconductors, enabling great potential in fabrication of logic, storage, optoelectronic, and photonic 2D devices with better performances than state-of-the-art ones. Toward the massive applications of highly integrated 2D devices, large-size 2D single crystals are a prerequisite for the ultimate quality of materials and extreme uniformity of properties. However, at present, it is still very challenging to grow all 2D single crystals into the wafer scale.

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