Nearly one century after the birth of quantum mechanics, parity–time symmetry is revolutionizing and extending quantum theories to include a unique family of non-Hermitian Hamiltonians. While ...conceptually striking, experimental demonstration of parity–time symmetry remains unexplored in quantum electronic systems. The flexibility of photonics allows for creating and superposing non-Hermitian eigenstates with ease using optical gain and loss, which makes it an ideal platform to explore various non-Hermitian quantum symmetry paradigms for novel device functionalities. Such explorations that employ classical photonic platforms not only deepen our understanding of fundamental quantum physics but also facilitate technological breakthroughs for photonic applications. Research into non-Hermitian photonics therefore advances and benefits both fields simultaneously.
The band degeneracy, either the exceptional point of a non-Hermitian system or the Dirac point associated with a topological system, can feature distinct symmetry and topology. Their synergy will ...further produce more exotic topological effects in synthetic matter.
For chiral hydrogels and related applications, one of the critical issues is how to control the chirality of supramolecular systems in an efficient way, including easy operation, efficient transfer ...of chirality, and so on. Herein, supramolecular chirality of l‐phenylalanine based hydrogels can be effectively controlled by using a broad range of metal ions. The degree of twisting (twist pitch) and the diameter of the chiral nanostructures can also be efficiently regulated. These are ascribed to the synergic effect of hydrogen bonding and metal ion coordination. This study may develop a method to design a new class of electronically, optically, and biologically active materials.
Opposite chiral nanotwists and non‐twisted nanofibers were successfully constructed by the self‐assembly of l‐phenylalanine derivatives in the presence of various kinds of metal ions. This process is mainly mediated by the formation of intermolecular hydrogen bonding and metal‐ion coordination, which can further induce different rearrangements and assemblies.
The design of evolutionary algorithms has typically been focused on efficiently solving a single optimization problem at a time. Despite the implicit parallelism of population-based search, no ...attempt has yet been made to multitask, i.e., to solve multiple optimization problems simultaneously using a single population of evolving individuals. Accordingly, this paper introduces evolutionary multitasking as a new paradigm in the field of optimization and evolutionary computation. We first formalize the concept of evolutionary multitasking and then propose an algorithm to handle such problems. The methodology is inspired by biocultural models of multifactorial inheritance, which explain the transmission of complex developmental traits to offspring through the interactions of genetic and cultural factors. Furthermore, we develop a cross-domain optimization platform that allows one to solve diverse problems concurrently. The numerical experiments reveal several potential advantages of implicit genetic transfer in a multitasking environment. Most notably, we discover that the creation and transfer of refined genetic material can often lead to accelerated convergence for a variety of complex optimization functions.
•The diffusion of technology through FDI depends on industrial linkage, firm capability, and location.•Chinese domestic firms benefit from foreign-owned suppliers but not from foreign customers or ...competitors.•Domestic firms benefit more from vertical linkage when they have higher absorptive capacity.
This paper explores how industrial linkages, firm capabilities, and the geographic location of domestic firms affect the diffusion of technology brought by foreign direct investment. I hypothesize that local firms are more likely to improve efficiency when they receive better product inputs from foreign suppliers and technology support by foreign customers, and such transfer of knowledge is more effective when the recipient has high absorptive capacity and is located near the source of knowledge. Empirical test using China’s manufacturing firms finds positive productivity spillovers between foreign suppliers and their domestic customers. However, there is no positive spillovers from foreign-owned customers or competitors. Domestic firms’ in-house R&D capital facilitates learning from foreign firms. Local firms learn from both joint ventures and wholly-owned foreign subsidiaries and the effects are larger from wholly-owned subsidiaries.
Due to its significant applications in many relevant fields, light detection in the solar‐blind deep‐ultraviolet (DUV) wavelength region is a subject of great interest for both scientific and ...industrial communities. The rapid advances in preparing high‐quality ultrawide‐bandgap (UWBG) semiconductors have enabled the realization of various high‐performance DUV photodetectors (DUVPDs) with different geometries, which provide an avenue for circumventing numerous disadvantages in traditional DUV detectors. This article presents a comprehensive review of the applications of inorganic UWBG semiconductors for solar‐blind DUV light detection in the past several decades. Different kinds of DUVPDs, which are based on varied UWBG semiconductors including Ga2O3, MgxZn1−xO, III‐nitride compounds (AlxGa1−xN/AlN and BN), diamond, etc., and operate on different working principles, are introduced and discussed systematically. Some emerging techniques to optimize device performance are addressed as well. Finally, the existing techniques are summarized and future challenges are proposed in order to shed light on development in this critical research field.
Recent advances in developing solar‐blind deep ultraviolet light (DUV) photodetectors based on various inorganic ultrawide‐bandgap semiconductors are reviewed, such as Ga2O3, MgxZn1−xO, III‐nitride compounds (AlxGa1−xN/AlN and BN), and diamonds.
Elaborate design of highly active and stable catalysts from Earth-abundant elements has great potential to produce materials that can replace the noble-metal-based catalysts commonly used in a range ...of useful (electro)chemical processes. Here we report, for the first time, a synthetic method that leads to in situ growth of {2̅10} high-index faceted Ni3S2 nanosheet arrays on nickel foam (NF). We show that the resulting material, denoted Ni3S2/NF, can serve as a highly active, binder-free, bifunctional electrocatalyst for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Ni3S2/NF is found to give ∼100% Faradaic yield toward both HER and OER and to show remarkable catalytic stability (for >200 h). Experimental results and theoretical calculations indicate that Ni3S2/NF’s excellent catalytic activity is mainly due to the synergistic catalytic effects produced in it by its nanosheet arrays and exposed {2̅10} high-index facets.
Supramolecular hydrogels assembled from amino acids and peptide‐derived hydrogelators have shown great potential as biomimetic three‐dimensional (3D) extracellular matrices because of their merits ...over conventional polymeric hydrogels, such as non‐covalent or physical interactions, controllable self‐assembly, and biocompatibility. These merits enable hydrogels to be made not only by using external stimuli, but also under physiological conditions by rationally designing gelator structures, as well as in situ encapsulation of cells into hydrogels for 3D culture. This review will assess current progress in the preparation of amino acids and peptide‐based hydrogels under various kinds of external stimuli, and in situ encapsulation of cells into the hydrogels, with a focus on understanding the associations between their structures, properties, and functions during cell culture, and the remaining challenges in this field. The amino acids and peptide‐based hydrogelators with rationally designed structures have promising applications in the fields of regenerative medicine, tissue engineering, and pre‐clinical evaluation.
Interest in amino acids and peptide‐based supramolecular hydrogels for 3D cell culture is increasing. This review assesses current progress in the preparation of these hydrogels under external stimuli and in situ cell encapsulation into the hydrogels, with a focus on understanding the associations between their structures, properties, and functions during cell culture and the remaining challenges.
Zero-energy particles (such as Majorana fermions) are newly predicted quasiparticles and are expected to play an important role in fault-tolerant quantum computation. In conventional Hermitian ...quantum systems, however, such zero states are vulnerable and even become vanishing if couplings with surroundings are of the same topological nature. Here we demonstrate a robust photonic zero mode sustained by a spatial non-Hermitian phase transition in a parity-time (PT) symmetric lattice, despite the same topological order across the entire system. The non-Hermitian-enhanced topological protection ensures the reemergence of the zero mode at the phase transition interface when the two semi-lattices under different PT phases are decoupled effectively in their real spectra. Residing at the midgap level of the PT symmetric spectrum, the zero mode is topologically protected against topological disorder. We experimentally validated the robustness of the zero-energy mode by ultrafast heterodyne measurements of light transport dynamics in a silicon waveguide lattice.
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