The enhanced compositional flexibility to incorporate multiple-principal cations in high entropy oxides (HEOs) offers the opportunity to expand boundaries for accessible compositions and ...unconventional properties in oxides. Attractive functionalities have been reported in some bulk HEOs, which are attributed to the long-range compositional homogeneity, lattice distortion, and local chemical bonding characteristics in materials. However, the intricate details of local composition fluctuation, metal-oxygen bond distortion and covalency are difficult to visualize experimentally, especially on the atomic scale. Here, we study the atomic structure-chemical bonding-property correlations in a series of perovskite-HEOs utilizing the recently developed four-dimensional scanning transmission electron microscopy techniques which enables to determine the structure, chemical bonding, electric field, and charge density on the atomic scale. The existence of compositional fluctuations along with significant composition-dependent distortion of metal-oxygen bonds is observed. Consequently, distinct variations of metal-oxygen bonding covalency are shown by the real-space charge-density distribution maps with sub-ångström resolution. The observed atomic features not only provide a realistic picture of the local physico-chemistry of chemically complex HEOs but can also be directly correlated to their distinctive magneto-electronic properties.
A study on optomechanically induced transparency (OMIT) and the output power at the Stokes (anti‐Stokes) frequency in a hybrid optomechanical system is presented. The system consists of a Fabry–Pérot ...cavity, two non‐absorbing membranes, and a degenerate optical parametric amplifier (OPA), where the coupling interaction between the cavity and each membrane is quadratic. This study shows that spacing between two transparency window dips in a wider detuning range and the higher transparency efficiency can be achieved by selecting the suitable strength of the quadratic coupling. In addition, it is also found that frequencies of the two mechanical membranes, the nonlinear gain of the OPA, and phase of the field driving OPA can exert a striking influence on the output power at the Stokes (anti‐Stokes) frequency. Specifically, with the increase of the nonlinear parameter of OPA, spacing between two dips on the normalized output power at the Stokes frequency becomes much wider for two membranes with the same frequency. Three peaks on the normalized output power at the anti‐Stokes frequency appear in a larger detuning. In quantum engineering, this scheme may have potential applications in enhancing the performance of OMIT devices.
A study on optomechanically induced transparency (OMIT) and the output power at the Stokes (anti‐Stokes) frequency is presented in a hybrid optomechanical system, where the coupling interaction between the cavity and each membrane is quadratic. In quantum engineering, this scheme may have potential applications in enhancing the performance of OMIT devices.
Schemes for converting photonic polarized‐entangled Knill–Laflamme–Milburn (KLM) states to Greenberger–Horne–Zeilinger (GHZ) states are proposed using weak cross‐Kerr nonlinearity and X‐quadrature ...homodyne measurement. Analyses show that the two‐qubit (Bell state) and three‐qubit conversion cases have very high fidelities and close‐to‐unity probabilities. The conversion processes are robust against photon loss. The schemes linking these two entangled states may be helpful to the study of quantum information processing based on them.
Based on weak cross‐Kerr nonlinearity, theoretical schemes are presented to bridge two multiple entanglements: Knill–Laflamme–Milburn (KLM) and Greenberger–Horne–Zeilinger (GHZ) entangled states. Adopting grouping and parity measurement, the KLM entanglement is decomposed into GHZ entanglement completely. Analyses considering photon loss show that high fidelities are reached for the two‐ and three‐qubit cases.
In this paper, the influence of Ca‐doping on microstructure and electrical characteristics of ZnO varistor ceramics is studied. With the increase of the doping concentration of calcium, the ZnO ...ceramics show strong directional growth along the Ca2MnO3.5 phase and the intensity of the X‐ray diffraction peaks of the Ca2MnO3.5 phase increase obviously, which indicates that the phase structure of ZnO ceramics is significantly affected by the calcium concentration. The average grain size of 0, 1, 2, and 3 mol% Ca‐doped ZnO ceramics is 7.2, 5.2, 4.8, and 4.2 µm, respectively, confirming the doping of Ca restrained the growth of grain in ceramics. The varistor ceramics doped with 1 mol% Ca have a density of 4.37 g cm−3, with a nonlinear coefficient of ∼41 at room temperature. They can be used to protect the electrical circuits from over voltages in the range of 280–460 V. Moreover, the ZnO ceramics show good temperature stability and the nonlinear coefficient changes slightly when the temperature changes from 25 to 150 °C; especially for varistor ceramics with 2 mol% Ca, the nonlinear coefficient is stable at about 37.
The influence of Ca‐doping on the microstructure and electrical characteristics of ZnO varistor ceramics is studied. The breakdown voltage is calculated as about 308 V mm−1 and the nonlinear coefficient is about 41 at 25 °C for the sample doped with 1 mol% Ca.
Herein, a novel visible-light responsive Ag/Ag3PO4/diatomite composites was successfully fabricated through a Deposition-Hydrothermal-Photoreduction method by using diatomite as the substrate. The ...crystal structure and morphology of the as-prepared samples were characterized by XRD, SEM, EDS and TEM. It can be found that a large number of spherical Ag/Ag3PO4 nanoparticles evenly loaded the surface of the diatomite substrate. The photocatalytic performances of the Ag/Ag3PO4/diatomite composites were evaluated by degradation RhB under visible-light irradiation (λ ≥ 420 nm). The effect of the adding amount of diatomite on the photocatalytic activity of the composite was also analyzed. The results indicated that the Ag/Ag3PO4/diatomite composites exhibit highest photocatalytic activity when the adding amount of diatomite reached 20%. The degradation rate of the Ag/Ag3PO4/diatomite-20% composites to RhB is as high as 90%, and the photoreaction kinetics constant value of the Ag/Ag3PO4/diatomite is 0.0371 which is 4.25 times higher than that of pure Ag3PO4 nanoparticles. Moreover, the mechanism of catalytic performance enhancement also has been discussed, the high photocatalytic performance of the Ag/Ag3PO4/diatomite composites can be attributed to the synergistic effect of Ag3PO4, diatomite and Ag nanoparticles. The radical trap experiments indicated that holes and O2− were served as the main active species. The Ag/Ag3PO4/diatomite composites synthesized via a facile and cost-effective route is a promising candidate in organics removal.
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•A novel Ag/Ag3PO4/diatomite composites were successfully synthesized.•The photocatalysis performance of the composites were studied under visible light.•The presence and influence of Ag3PO4 particles in diatomite matrix was systematically analyzed.•The Ag/Ag3PO4/diatomite composites exhibit excellent photocatalytic activity and stability.
In order to improve the response capability of cross regional emergency material scheduling (CREMS), a CREMS algorithm based on seed optimization algorithm is proposed. Construct a segmented regional ...grid distribution model structure for CREMS, use a grid matching algorithm based on block link distribution to construct the optimization objective function during the emergency material scheduling process, use variable neighborhood search technology to solve the diversity problem of cluster optimization in CREMS, and combine seed optimization algorithms for combination control and recursive analysis in the emergency material scheduling process. Based on the combination of deep learning and reinforcement learning, the optimal route and configuration scheme design for CREMS process is achieved. The simulation results show that this method has better active configuration capability, better path optimization capability and stronger spatial regional planning capability for CREMS.
Abstract
Optical fiber bending, deformation or shape sensing are important measurement technologies and have been widely deployed in various applications including healthcare, structural monitoring ...and robotics. However, existing optical fiber bending sensors require complex sensor structures and interrogation systems. Here, inspired by the recent renewed interest in information-rich multimode optical fibers, we show that the multimode fiber (MMF) output speckles contain the three-dimensional (3D) geometric shape information of the MMF itself. We demonstrate proof-of-concept 3D multi-point deformation sensing via a single multimode fiber by using
k
-nearest neighbor (KNN) machine learning algorithm, and achieve a classification accuracy close to 100%. Our results show that a single MMF based deformation sensor is excellent in terms of system simplicity, resolution and sensitivity, and can be a promising candidate in deformation monitoring or shape-sensing applications.
Carbon aerogels are elastic, mechanically robust and fatigue resistant and are known for their promising applications in the fields of soft robotics, pressure sensors etc. However, these aerogels are ...generally fragile and/or easily deformable, which limits their applications. Here, we report a synthesis strategy for fabricating highly compressible and fatigue-resistant aerogels by assembling interconnected carbon tubes. The carbon tube aerogels demonstrate near-zero Poisson's ratio, exhibit a maximum strength over 20 MPa and a completely recoverable strain up to 99%. They show high fatigue resistance (less than 1.5% permanent degradation after 1000 cycles at 99% strain) and are thermally stable up to 2500 °C in an Ar atmosphere. Additionally, they possess tunable conductivity and electromagnetic shielding. The combined mechanical and multi-functional properties offer an attractive material for the use in harsh environments.
Asymmetric total synthesis of structurally intriguing and highly oxygenated lancifodilactone G acetate (7) has been achieved for the first time in 28 steps from a cheap commodity chemical, ...2-(triisopropylsiloxy)-1,3-butadiene.
Aggregation-induced emission (AIE) is an intriguing strategy to enhance the luminescence of metal nanoclusters (NCs). However, the morphologies of aggregated NCs are often irregular and ...inhomogeneous, leading to instability and poor color purity of the aggregations, which greatly limit their further potential in optical applications. Inspired by self-assembly techniques, manipulating metal NCs into well-defined architectures has achieved success. The self-assembled metal NCs often exhibit enhancing emission stability and intensity compared to the individually or randomly aggregated ones. Meanwhile, the emission color of metal NCs becomes tunable. In this review, we summarize the synthetic strategies involved in self-assembly of metal NCs for the first time. For each synthetic strategy, we describe the self-assembly mechanisms involved and the dependence of optical properties on the self-assembly. Finally, we outline the current challenges to and perspectives on the development of this area.
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