Search

It is exceedingly desired yet challenging to steer the photocatalytic overall CO2 reduction reaction (CRR) toward high-value liquid products, especially multicarbon products like ethanol. Numerous attempts have been reported such as developing new materials, cocatalyst engineering, etc. Here, we find that by just curling the superhydrophobic Cu2O to create an enclosed Cu2O hollow structure, the selectivity of ethanol (59.59%) is impressively elevated by ~ 9 times higher than that without the enclosed hollow structure. Further investigations indicate that the superhydrophobic hollow structure can efficiently repel water out and thus create an enclosed gas storage space, enabling the high concentration of CO2 molecules. With such a strategy, an impressive ethanol generation rate of 996.18 µmol g− 1 h− 1 is achieved. The mechanism is also investigated based on theoretical calculations and corresponding characterizations. This strategy provides a geometry-modulated method with high compatibility, which is promising to develop more efficient photocatalysts for multicarbon production combined with other traditional methods.

With the rapid development of Web3D technologies, sketch-based model retrieval has become an increasingly important challenge, while the application of Virtual Reality and 3D technologies has made shape retrieval of furniture over a web browser feasible. In this paper, we propose a learning framework for shape retrieval based on two Siamese VGG-16 Convolutional Neural Networks (CNNs), and a CNN-based hybrid learning algorithm to select the best view for a shape. In this algorithm, the AlexNet and VGG-16 CNN architectures are used to perform classification tasks and to extract features, respectively. In addition, a feature fusion method is used to measure the similarity relation of the output features from the two Siamese networks. The proposed framework can provide new alternatives for furniture retrieval in the Web3D environment. The primary innovation is in the employment of deep learning methods to solve the challenge of obtaining the best view of 3D furniture, and to address cross-domain feature learning problems. We conduct an experiment to verify the feasibility of the framework and the results show our approach to be superior in comparison to many mainstream state-of-the-art approaches.

Spontaneous orbital symmetry breaking in crystals gives rise to abundant novel and interesting physical properties, which sometimes are concealed by the absence of geometrical distortions. We show that a recently discovered 3d2 system, namely the layered VI3 ferromagnetic semiconductor, is a strongly correlated and orbital ordering system. Our analysis reveals that in a VI3-like system, there could be two types of orbital splitting, which are stabilized respectively by strong electronic correlation and inter-atomic exchange interactions. Consequently, on the basis of first-principles calculations, two competing low-energy phases of VI3 monolayer (denoted as twin orbital-order phases) are discovered, in which the metal–insulator transition is driven by strong electronic correlation, and the orbital symmetry breaking is robust against geometrical distortions. In addition, similar phenomena are also observed in other VI3-like systems. These findings shed light on the unusual electronic behavior of a strongly correlated 2D system and will be interesting for nanoscale multi-functional spintronic applications.

To support intelligent manufacturing, providing a unified production data view by integrating distributed data collected by different enterprise information systems is critical. Because various information systems are often heterogeneous, ontology is widely adopted to present a global reference view for data integration. However, construction and maintenance of these ontologies is difficult because of the heterogeneity and dynamism of these large-scale data. In this paper, with the objective of intelligent manufacturing application implementation, we propose a comprehensive ontology generation and evolution method that automatically abstracts ontology from raw production data and dynamically adjusts the ontology in accordance with changes in the manufacturing data environment. The proposed method comprises four phases: data extraction, ontology construction, ontology connection, and ontology evolution. In the first phase, data from different sources are mapped to data entities to form a unified data structure. In the second phase, an initial ontology is generated via instance-driven ontology construction. In the third phase, to support intelligent manufacturing, the initial ontologies are organised in terms of the dimensions of the various business elements, such as stuff, machine, product, process, and scenarios. In the fourth phase, rules regarding ontology restrictions are formulated to realise ontology evolution that respond to changes in the manufacturing environment. To verify the efficacy of the proposed method, a prototype was implemented with real data from a manufacturing factory, in which the constructed ontology was used as the metadata of product data in intelligent manufacturing.

Metal-organic frameworks (MOFs), comprised of organic ligands and metal ions/metal clusters via coordinative bonds are highly porous, crystalline materials. Their tunable porosity, chemical composition, size and shape, and easy surface functionalization make this large family more and more popular for drug delivery. There is a growing interest over the last decades in the design of engineered MOFs with controlled sizes for a variety of biomedical applications. This article presents an overall review and perspectives of MOFs-based drug delivery systems (DDSs), starting with the MOFs classification adapted for DDSs based on the types of constituting metals and ligands. Then, the synthesis and characterization of MOFs for DDSs are developed, followed by the drug loading strategies, applications, biopharmaceutics and quality control. Importantly, a variety of representative applications of MOFs are detailed from a point of view of applications in pharmaceutics, diseases therapy and advanced DDSs. In particular, the biopharmaceutics and quality control of MOFs-based DDSs are summarized with critical issues to be addressed. Finally, challenges in MOFs development for DDSs are discussed, such as biostability, biosafety, biopharmaceutics and nomenclature., Graphical abstract This review focuses on metal–organic frameworks (MOFs)-based drug delivery systems (DDSs), including classification, synthesis, characterization, applications and biopharmaceutics of MOFs for DDSs.Image 1

Since the recent experimental discovery of the CrI3 and CrGeTe3 monolayers, van der Waals (vdW) layered transition metal compounds have been recognized as promising candidates to realize 2D ferromagnetic (FM) semiconductors. However, until now, only limited compounds have been proposed to be ferromagnetic semiconductors. Here, on the basis of first-principles calculations, we report that the monolayer, Janus monolayer, and bilayer of NiX2 (X = Cl, Br, I) are intrinsic 2D FM semiconductors. Our results show that exfoliation energy of the NiX2 monolayer is smaller than that of graphene, and all studied NiX2 layers show semiconducting band gaps. The predicted Curie temperature values for NiX2 (X = Cl, Br, I) monolayers ranged from 120 to 170 K with Monte Carlo simulations. For the Janus monolayer, we found that the spin interaction shows a very strong magnetoelectric coupling under an external electric field. Furthermore, for the bilayer of NiX2, our results show that the interlayer coupling is quite weak, i...

Mobile applications are widely used to provide users convenient and friendly service experiences. Meanwhile, service logs generated by mobile applications are analyzed to obtain user behavior patterns for monitoring and optimizing mobile application performances. However, due to the frequent updates in mobile application, situations of concept drifts often occur in service log streams, which lead to challenges in mobile process mining. In this paper, a novel framework is proposed to solve the above problems by combining fog-computing-based concept drift detecting with cloud-computing-based process mining. Firstly, incomplete log data are preprocessed using fog-computing technologies to provide more accurate log contexts and lower overhead. Then, concept drift detecting methods are used in cloud computing layer to deal with the transfer of mobile applications from one version to another. Finally, experimental results demonstrate that our framework can deduce missed case identifiers for logs when concept drifts happen.

Electrical control of magnetism in a two-dimensional (2D) semiconductor is of great interest for emerging nanoscale low-dissipation spintronic devices. Here, we propose a general approach of tuning magnetic coupling and anisotropy of a van der Waals (vdW) 2D magnetic semiconductor via a built-in electric field generated by the adsorption of superatomic ions. Using first-principles calculations, we predict a significant enhancement of ferromagnetic (FM) coupling and a great change of magnetic anisotropy in 2D semiconductors when they are sandwiched between superatomic cations and anions. The magnetic coupling is directly affected by the built-in electric field, which lifts the energy levels of mediated ligands' orbitals and enhances the super-exchange interactions. These findings will be of interest for ionic gating controlled ferromagnets and magnetoelectronics based on vdW 2D semiconductors.

In spite of decades of research, a fundamental understanding of the unusual magnetic behavior of small Mn clusters remains a challenge. Experiments show that Mn2 is antiferromagnetic while small clusters containing up to five Mn atoms are ferromagnetic with magnetic moments of 5 μB/atom and become ferrimagnetic as they grow further. Theoretical studies based on density functional theory (DFT), however, find Mn2 to be ferromagnetic, with ferrimagnetic order setting in at different sizes that depend upon the computational methods used. While quantum chemical techniques correctly account for the antiferromagnetic ground state of Mn2, they are computationally too demanding to treat larger clusters, making it difficult to understand the evolution of magnetism. These studies clearly point to the importance of correlation and the need to find ways to treat it effectively for larger clusters and nanostructures. Here, we show that the DFT+U method can be used to account for strong correlation. We determine the on-...

Controlling magnetism of two-dimensional multiferroics by an external electric field provides special opportunities for both fundamental research and future development of low-cost electronic nanodevices. Here, we report a general scheme for realizing a magnetic phase transition in 2D type-I multiferroic systems through the reversal of ferroelectric polarization. Based on first-principles calculations, we demonstrate that a single-phase 2D multiferroic, namely, ReWCl_{6} monolayer, exhibits two different low-symmetric (C_{2}) phases with opposite in-plane electric polarization and different magnetic order. As a result, an antiferromagnetic-to-ferromagnetic phase transition can be realized by reversing the in-plane electric polarization through the application of an external electric field. These findings not only enrich the 2D multiferroic family, but also uncover a unique and general mechanism to control magnetism by electric field, thus stimulating experimental interest.

Encapsulation strategies are widely used for alleviating dissolution and diffusion of polysulfides, but they experience nonrecoverable structural failure arising from the repetitive severe volume change during lithium−sulfur battery cycling. Here we report a methodology to construct an electrochemically recoverable protective layer of polysulfides using an electrolyte additive. The additive nitrogen-doped carbon dots maintain their “dissolved” status in the electrolyte at the full charge state, and some of them function as active sites for lithium sulfide growth at the full discharge state. When polysulfides are present amid the transition between sulfur and lithium sulfide, nitrogen-doped carbon dots become highly reactive with polysulfides to form a solid and recoverable polysulfide-encapsulating layer. This design skilfully avoids structural failure and efficiently suppresses polysulfide shuttling. The sulfur cathode delivers a high reversible capacity of 891 mAh g−1 at 0.5 C with 99.5% coulombic efficiency and cycling stability up to 1000 cycles at 2 C., Inspired by the processes of thrombus formation and thrombolysis in blood vessels, the authors here construct an electrochemically recoverable protective layer of polysulfides using an electrolyte additive, realizing high performance Li–S batteries.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause acute respiratory disease and multiorgan failure. Finding human host factors that are essential for SARS-CoV-2 infection could facilitate the formulation of treatment strategies. Using a human kidney cell line—HK-2—that is highly susceptible to SARS-CoV-2, we performed a genome-wide RNAi screen and identified virus dependency factors (VDFs), which play regulatory roles in biological pathways linked to clinical manifestations of SARS-CoV-2 infection. We found a role for a secretory form of SARS-CoV-2 receptor, soluble angiotensin converting enzyme 2 (sACE2), in SARS-CoV-2 infection. Further investigation revealed that SARS-CoV-2 exploits receptor-mediated endocytosis through interaction between its spike with sACE2 or sACE2-vasopressin via AT1 or AVPR1B, respectively. Our identification of VDFs and the regulatory effect of sACE2 on SARS-CoV-2 infection shed insight into pathogenesis and cell entry mechanism of SARS-CoV-2 as well as potential treatment strategies for COVID-19., Using an infection-permissive human kidney cell line, Yeung et al. show that a soluble form of ACE2 that is cleaved and liberated from the host cell surface mediates SARS-CoV-2 binding and uptake by receptors involved in renin-angiotensin system signaling.

As the base of modern electronic industry, field-effect transistor (FET) requires the channel material to have both moderate bandgap and high mobility. The recent progresses indicate that few-layer black phosphorus has suitable bandgap and higher mobility than two-dimensional (2D) MoS2, but the experimentally achieved maximal mobility (1000 cm2V−1 s−1) is still obviously lower than those of classical semiconductors (1,400 and 5,400 cm2V−1 s−1 for Si and InP). Here, for the first time, we report on monolayer antimonide phosphorus (SbP) as a promising 2D channel material with suitable direct bandgap, which can satisfy the on/off ratio, and with mobility as high as 104 cm2 V−1 s−1 based on density functional theory calculation. In particular, α-Sb1−x P x monolayers possess 0.3–1.6 eV bandgaps when 0.1 ≤ x ≤ 1, which are greater than the minimum bandgap (0.4 eV) required for large on/off ratio of FET. Surprisingly, the carrier mobilities of α-Sb1−x P x monolayers exhibit very high upper limit approaching 2×104 cm2 V−1 s−1 when 0 ≤ x ≤ 0.25 due to the ultra-small effective mass of holes and electrons. This work reveals that 2D SbP with both suitable bandgap and high mobility could be a promising candidate as eco-friendly high-performance FET channel materials avoiding short-channel effect in the post-silicon era, especially when considering the recent experimental success in realizing arsenide phosphorus (AsP) with similar structure.

The Transiting Exoplanet Survey Satellite TESS has begun a new age of exoplanet discoveries around bright host stars. We present the discovery of HD 1397b (TOI-120.01), a giant planet in an 11.54day eccentric orbit around a bright (V=7.9) G-type subgiant. We estimate both host star and planetary parameters consistently using EXOFASTv2 based on TESS time-series photometry of transits and CORALIE radial velocity measurements. We find that HD 1397b is a Jovian planet, with a mass of $0.419\pm-0.024$ M$_{\rm Jup}$ and a radius of $1.023^{+0.023}_{-0.026$}$ R$_{\rm Jup}$. Characterising giant planets in short-period eccentric orbits, such as HD 1397b, is important for understanding and testing theories for the formation and migration of giant planets as well as planet-star interactions., Accepted for publication in A&A

Although the quantum anomalous Hall (QAH) effect has been experimentally observed in several magnetically doped topological insulators, up to now, it only survives at a very low temperature. More suitable candidate QAH insulators that can work at high temperature are much desired. Here, we propose an experimentally feasible way to realize a robust QAH insulator: atomically dispersed transition metals (e.g., W) on a two-dimensional porous metal halide normal insulator (e.g., ${\mathrm{InI}}_{3}$), which has been developed as a state-of-the-art chemical technology broadly adopted for homogeneous catalysis. Based on the first-principles calculations, we predict that the atomic W embedded in an ${\mathrm{InI}}_{3}$ monolayer forms an intrinsic ferromagnetic QAH insulator, which exhibits robust uniform out-of-plane ferromagnetic order up to $\ensuremath{\sim}160\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and a topologically nontrivial band gap of 56 meV with a nonzero Chern number $(|C|=2)$. We also study its magneto-optical Kerr effect and collective plasma excitation modes, which may help for further experimental verifications and measurement of interesting physical features of Dirac-like electronic dispersion. Our results introduce a feasible method to obtain the QAH effect, which may motivate intensive experimental interest in this field.

The realization of multiferroics in nanostructures, combined with a large electric dipole and ferromagnetic ordering, could lead to new applications, such as high-density multistate data storage. Although multiferroics have been broadly studied for decades, ferromagnetic ferroelectricity is rarely explored, especially in two-dimensional (2D) systems. Here we report the discovery of 2D ferromagnetic ferroelectricity in layered transition-metal halide systems. On the basis of first-principles calculations, we reveal that a charged CrBr_{3} monolayer exhibits in-plane multiferroicity, which is ensured by the combination of orbital and charge ordering as realized by the asymmetric Jahn-Teller distortions of octahedral Cr─Br_{6} units. As an example, we further show that (CrBr_{3})_{2}Li is a ferromagnetic ferroelectric multiferroic. The explored phenomena and mechanism of multiferroics in this 2D system not only are useful for fundamental research in multiferroics but also enable a wide range of applications in nanodevices.

The quantum anomalous Hall (QAH) effect is a novel topological spintronic phenomenon arising from inherent magnetization and spin-orbit coupling. Various theoretical and experimental efforts have been devoted in search of robust intrinsic QAH insulators. However, up to now, it has only been observed in Cr or V doped (Bi,Sb)2Te3 film in experiments with very low working temperature. Based on the successful synthesis of transition metal halides, we use first-principles calculations to predict that RuI3 monolayer is an intrinsic ferromagnetic QAH insulator with a topologically nontrivial global band gap of 11 meV. This topologically nontrivial band gap at the Fermi level is due to its crystal symmetry, thus the QAH effect is robust. Its Curie temperature, estimated to be ~360 K using Monte-Carlo simulation, is above room temperature and higher than most of two-dimensional ferromagnetic thin films. We also discuss the manipulation of its exchange energy and nontrivial band gap by applying in-plane strain. Our work adds a new experimentally feasible member to the QAH insulator family, which is expected to have broad applications in nanoelectronics and spintronics., 6 figures; accepted in PRB

Over the past few years, various valleytronic properties have been predicted in graphene like $p$-electron honeycomb structures with staggered sublattice onsite potential; however, most of these studies are based on model calculations, and direct studies on real materials are still rare. In this paper, we propose an experimentally feasible structure based on an epitaxial growth of In/Tl honeycomb lattice on a semihydrogenated graphene/diamond thin film substrate. Our first-principles calculations reveal that due to different absorption sites of the two In/Tl sublattices, the inversion symmetry and quasi-two-dimensional inversion symmetry are broken, yielding inequivalent band gaps at the $K$ and ${K}^{\ensuremath{'}}$ points of the Brillouin zone. In addition, compared with previous graphene-based models, In/Tl also has a large spin-orbit coupling (SOC). In this regard, such a $p$-electron based system is a good candidate for valley selective circular polarization light absorption. Simultaneously, by integrating its Berry curvatures, we reveal a large SOC induced anomalous Nernst effect, which supports a pure spin current at its Fermi level.