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In this paper, the content service provision of information-centric vehicular networks (ICVNs) is investigated from the aspect of mobile edge caching, considering the dynamic driving-related context information. To provide up-to-date information with low latency, two schemes are designed for cache update and content delivery at the roadside units (RSUs). The roadside unit centric (RSUC) scheme decouples cache update and content delivery through bandwidth splitting, where the cached content items are updated regularly in a round-robin manner. The request adaptive (ReA) scheme updates the cached content items upon user requests with certain probabilities. The performance of both proposed schemes are analyzed, whereby the average age of information (AoI) and service latency are derived in closed forms. Surprisingly, the AoI-latency trade-off does not always exist, and frequent cache update can degrade both performances. Thus, the RSUC and ReA schemes are further optimized to balance the AoI and latency. Extensive simulations are conducted on SUMO and OMNeT++ simulators, and the results show that the proposed schemes can reduce service latency by up to 80% while guaranteeing content freshness in heavily loaded ICVNs.

Global warming effect caused by excessive emission of greenhouse gases, such as CO2 from modern industries, are emerging as serious environmental problem nowadays. Many strategies have been developed to address this issue, including solar energy utilization, green plants cultivation and coal desulfurization. These existing strategies always need sophisticated equipment and harsh reaction conditions, and are usually with limited efficiency. With the development of nanoscience and nanotechnology, it is becoming an effective strategy to directly capture and convert CO2 with nanomaterials into valuable chemicals under gentle conditions. Herein, we summarize recent progress on nanomaterials for adsorption and conversion of CO2 under gentle conditions, including various physical and chemical processes, and artificial photosynthesis. Future perspective and research direction of nanomaterials for CO2 adsorption and conversion have been put forward on the basis of existing research works and our experimental experience.

Metastasis due to circulating tumor cells (CTCs) shed from the original tumor accounts for the majority of cancer-related death. Efficient CTCs detection is pivotal to the diagnosis of early cancer metastasis. In this work, Platinum nanoparticles (PtNPs) decorated hyperbranched PdRu nanospines (PdRu/Pt) hierarchical structures were firstly synthesized to detect CTCs with the assistance of DNAzyme. Meanwhile, Super P and gold nanoparticles (AuNPs) acted as sensing medium to improve electrical conductivity and immobilization of anti-EpCAM antibody to specifically capture model CTCs. After immune-conjugation of anti-EpCAM-MCF-7-signal probes on the gold electrode, PtNPs, PdRu nanospines (PdRuNSs) and hemin/G-quadruplex co-catalyzed substrate H2O2 to realize multiplexed signal amplification, which significantly improves the analytical performance of the electrochemical biosensor. As-proposed biosensor reached a limit of detection (LOD) down to 2 cells mL−1 and showed a wide detection range of 2 to 106 cells mL−1. Application of the biosensor to detect MCF-7 cells spiked human blood samples further demonstrated the feasibility for early cancer evaluation in clinic.

Near-infrared (NIR)-activable liposomes containing photosensitizer (PS)-lipid conjugates are emerging as tunable, high-payload, and tumor-selective platforms for photodynamic therapy (PDT)-based theranostics. To date, the impact that the membrane composition of a NIR-activable liposome (the chemical nature and subsequent conformation of PS-lipid conjugates) has on their in vitro and in vivo functionality has not been fully investigated. While their chemical nature is critical, the resultant physical conformation dictates their interactions with the immediate biological environments. Here, we evaluate NIR-activable liposomes containing lipid conjugates of the clinically-used PSs benzoporphyrin derivative (BPD; hydrophobic, membrane-inserting conformation) or IRDye 700DX (hydrophilic, membrane-protruding conformation) and demonstrate that membrane composition is critical for their function as tumor-selective PDT-based platforms. The PS-lipid conformations were primarily dictated by the varying solubilities of the two PSs and assisted by their lipid conjugation sites. Conformation was further validated by photophysical analysis and computational predictions of PS membrane partitioning (topological polar surface area [tPSA], calculated octanol/water partition [cLogP], and apparent biomembrane permeability coefficient [Papp]). Results show that the membrane-protruding lipo-IRDye700DX exhibits 5-fold more efficient photodynamic generation of reactive molecular species (RMS), 12-fold expedited phototriggered burst release of entrap-ped agents, and 15-fold brighter fluorescence intensity as compared to the membrane-inserting lipo-BPD-PC (phosphatidylcholine conjugate). Although the membrane-inserting lipo-BPD-PC exhibits less efficient photo-dynamic generation of RMS, it allows for more sustained phototriggered release, 10-fold greater FaDu cancer cell phototoxicity, and 7.16-fold higher tumor-selective delivery in orthotopic mouse FaDu head and neck tumors. These critical insights pave the path for the rational design of emerging NIR-activable liposomes, whereby functional consequences of membrane composition can be tailored toward a specific therapeutic purpose.

High-entropy alloys have attracted broad research interests due to their unique and intriguing mechanical properties. As a category of high-entropy alloys, eutectic high-entropy alloys combine the advantages of eutectic and high-entropy alloys, with excellent mechanical properties and casting properties. Some eutectic high-entropy alloys have been developed and shown exciting properties. In this paper, based on the physical metallurgy of eutectic high-entropy alloy, medium-entropy alloy Fe2NiCrNbx was designed. The as-cast alloy is composed of FCC and Laves phases, Nb element promotes the formation of primary Laves phase, and the hardness of the alloy increases with the increase in Nb element. Among the four alloys, the eutectic chemical composition at eutectic point is Fe2NiCrNb0.34; the alloy has a good strength and plastic balance. The ultimate comprehensive strength is 2267MPa, and the fracture strain is 30.8%. The experiment data and analyses identified the eutectic points and the excellent mechanical behavior. Moreover, the expensive Co element was replaced by Fe element. This cheap medium-entropy alloy has promising prospect in the consideration of the cost performance ratio.

Recrystallization has been a major method to induce heterogeneous grain structure for improving the strength–ductility combination of single-phase high-entropy alloys (HEAs). However, the recrystallization kinetics, which are the guideline for controlling the recrystallization behavior, of single-phase HEAs are relatively less explored. Here, we uncover the recrystallization behaviors of typical single-phase NiCoCrFe and Ni2CoCrFe HEAs. Our results showed that the two investigated HEAs exhibit almost similar recrystallization activation energy around 230 kJ·mol−1, but distinctively different recrystallization kinetics. This abnormal difference is attributed to the deformation twins of NiCoCrFe. These findings indicate that, except for textbook factors, deformation twinning significantly enhances the recrystallization behavior of HEAs.

Ti-15Nb-25Zr-(0, 4, 8)Fe (mol.%) alloys were prepared via spark plasma sintering (SPS) for 10 min at 800, 1000, and 1200 °C to study the effect of sintering temperatures and Fe content on the mechanical properties of alloys. The main phase of the alloys sintered at 800 °C is α phase. When the temperature is increased to 1000 and 1200 °C, the alloys are mainly β phase. Raising the sintering temperature can promote the diffusion of elements. Therefore, high strength and high plasticity are obtained in the alloys sintered at high temperature. The compressive strength of Ti-15Nb-25Zr sintered at 1200 °C is 1604 MPa, and the fracture strain is around 35%. The strength and plasticity are influenced by the complex effects of elemental diffusion, grain boundary and solid-solution strengthening. Adding Fe can improve the diffusion of elements, promote the formation of β grains and supply solid-solution strengthening effect. As the sintering temperature is increased, the compressive strength of Ti-15Nb-25Zr-4Fe shows an increasing trend and the plasticity is almost not changed. The Fe content is excessive in Ti-15Nb-25Zr-8Fe, which leads to some disadvantages including intermetallic compounds formation and grain boundary coarsening. The mechanical properties of Ti-15Nb-25Zr-8Fe are not always better than those of Ti-15Nb-25Zr-4Fe. The compressive strength of Ti-15Nb-25Zr-8Fe shows an increasing trend and the plasticity firstly increases and then decreases when the temperature is raised from 800 up to 1200 °C. Although the sintering time of SPS is short, Ti-15Nb-25Zr-(4, 8)Fe sintered at 1000 °C and Ti-15Nb-25Zr-(0, 4)Fe sintered at 1200 °C show good combination of strength and plasticity.

In this article, a novel control method is proposed to control capacitor voltages for the T-type five-level nested neutral point piloted (5L-NNPP) converter. Due to the diversity of switching states for NNPP topology, there is no guarantee that the redundant vectors have the opposite effect on the dc bus neutral voltage. Meanwhile, the voltage balance controls between the dc bus neutral voltage and three-phase flying capacitor voltage are coupled and interacted with each other in the 5L-NNPP converter. This has severe voltage balance problems with the conventional space vector modulation (SVM), which limits its wide applications, especially under low output frequency. To solve the voltage balance problems, an improved SVM and voltage balance control (VBC) function are proposed to balance dc bus capacitor voltages and flying capacitor voltages, which realizes decoupling of voltage control. The switching states, switching principle, and dwell time calculation are developed, and the flowchart of VBC function is also elaborated on. The performance of the proposed improved SVM is investigated and compared with conventional SVM. The effectiveness and validity of the improved SVM with a VBC function is verified by simulation and experimental results of the 5L-NNPP converter.

Precipitation-hardened high entropy alloys (HEAs) with carefully tuned compositions have shown excellent mechanical properties, demonstrating great potential for engineering applications. However, due to the lack of precise multiple phase diagrams, the composition design of multi-principal-component HEAs still inevitably relies on the extremely time-consuming trial-and-error approach. The present study, on the basis of powerful composition quantification ability of atom probe tomography (APT) technology, proposed a framework to guide the quantitative design of precipitation-hardened HEAs. In this framework, the elemental partitioning was used as a crucial route to avoid the thermodynamic challenge of designing precipitation-hardened HEAs. As a case study, the role of Ti/Al ratio in the design of γ-γ′ HEAs was predicted through the proposed framework and then validated by experimental studies. The framework predicted that when the total content of Ti and Al is fixed, a higher Ti/Al ratio makes γ-γ′ HEA stronger. APT and mechanical results agreed well with these predictions and validated the feasibility of the framework. These findings provided a new route to design the precipitation-hardened alloys and a deeper insight into the design of γ-γ′ HEA.

Lithium-rich manganese-based layered oxides (LRMOs) offer joint cationic and anionic redox at a high voltage, thus promising high energy density for lithium-ion batteries (LIBs). However, the restive anion redox is also connected with poor rate performance, severe capacity fading, and continuous voltage decay. Herein, a successful strategy for enhancing the Li+ ion diffusivity and structure stability of LRMOs is proposed. The obtained material possesses high cationic and anionic redox activity due to the introduction of Te6+. Moreover, a heterogeneous protective layer that is composed of acid-resistant Mg3(PO4)2 and self-induced cation-disordered phase with passivated lattice oxygen is verified to be located on the surface of the material, thereby restraining the structural degeneration. Benefitting from the unique architecture, the modified material presents a favorable cycling performance and excellent rate capability (178.8 mA h g-1, 10 C). More importantly, the voltage decay is significantly suppressed during cycling. The finding here exhibits the importance of activating cationic and anionic redox in the bulk and passivating surface oxygen for enhancing reversible capacity at high rates and improving structural stability, providing a ponderable way to promote the electrochemical performance of LRMOs.

The multi-principal-component concept of high-entropy alloys (HEAs) generates numerous new alloys. Among them, nanoscale precipitated HEAs have achieved superior mechanical properties and shown the potentials for structural applications. However, it is still a great challenge to find the optimal alloy within the numerous candidates. Up to now, the reported nanoprecipitated HEAs are mainly designed by a trial-and-error approach with the aid of phase diagram calculations, limiting the development of structural HEAs. In the current work, a novel method is proposed to accelerate the development of ultra-strong nanoprecipitated HEAs. With the guidance of physical metallurgy, the volume fraction of the required nanoprecipitates is designed from a machine learning of big data with thermodynamic foundation while the morphology of precipitates is kinetically tailored by prestrain aging. As a proof-of-principle study, an HEA with superior strength and ductility has been designed and systematically investigated. The newly developed γ′-strengthened HEA exhibits 1.31 GPa yield strength, 1.65 GPa ultimate tensile strength, and 15% tensile elongation. Atom probe tomography and transmission electron microscope characterizations reveal the well-controlled high γ′ volume fraction (52%) and refined precipitate size (19 nm). The refinement of nanoprecipitates originates from the accelerated nucleation of the γ′ phase by prestrain aging. A deeper understanding of the excellent mechanical properties is illustrated from the aspect of strengthening mechanisms. Finally, the versatility of the current design strategy to other precipitation-hardened alloys is discussed.

Black phosphorus has been reported as a remarkable 2D material due to its unique electrical, optical, and thermal properties, leading to promising device applications in optics, thermoelectricity, ...

Cathode interface instability is a significant obstacle for the practical application of sulfide-based all-solid-state lithium-ion batteries (ASSLIBs). However, the origin of cathode interface degradation is lack of comprehensive understanding. In this paper, X-ray characterizations combined with electrochemical analysis are adopted to investigate the underlying degradation mechanism at cathode interface. The results indicate that residual lithium compounds on the surface of Ni-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) are the main reason that triggering the oxidation of sulfide solid-state electrolytes (SSEs), therefore inducing severe side-reactions at cathode interface and structural degradation of NMC811. The degradation of the cathode interface can be significantly suppressed when the cathode surface is cleaned. As a result, the surface cleaned NMC811 without coating demonstrates significantly improved electrochemical performance in both Li5.5PS4.5Cl1.5 (LPSCl) and Li10GeP2S12 (LGPS) based ASSLIBs, proving the universal application of this strategy.

Rockfalls are a major hazard in mountain areas and along engineering slopes. It is important to fully understand the characteristics and processes of rockfall movements, both for hazard assessment and countermeasure design. This study focused on the movement characteristics and disaster processes of rockfalls by three-dimensional discontinuous deformation analysis (3D-DDA), the effectiveness of which was verified by outdoor experiments. An apparatus specifically built for the experiments was established, which included a releasing device and a binocular camera stereovision system. Blocks of three different shapes and sizes were released on slopes with three different inclinations on the campus of Tibet University. The indices of the movement characteristics of the blocks, such as lateral deviation, resting position, jumping height, and kinetic energy evolution, were investigated. The experimental results were compared with those of the 3D-DDA, so as to study the rockfall movement characteristics. On this basis, the 3D-DDA was applied to simulate a large-scale slope rockfall on the Tibetan Plateau, and the rockfall failure processes and movement characteristics were further analyzed. The results showed that the 3D-DDA method could effectively simulate the entire rockfall process in time and space, including instability and movement. Through the 3D-DDA numerical simulations, rockfall phenomena and behaviors could be fully understood. Furthermore, by analyzing the trajectories and kinetic energies of a rockfall, the prediction of rockfall disasters and the reasonable design of protective countermeasures could be realized.

As an inherent characteristic of light, polarization plays important roles in information storage, display and even encryption. Metasurfaces, composed of specifically designed subwavelength units in a two-dimensional plane, offer a great convenience for polarization manipulation, yet improving their integrability and broadband fidelity remain significant challenges. Here, based on the combination of various subwavelength cross-nanofins (CNs), a new type of metasurface for multichannel hybrid polarization distribution in near-field is proposed. Sub-wavelength CN units with various waveplate (WP) functionalities, such as frequency-division multiplexing WP, half-WP and quarter-WP are implemented with high efficiency in broadband. High-resolution grayscale image encryption, multi-image storage and rapid polarization detection are demonstrated by encoding the WP pixels into single, double and four channels, respectively. All these applications possess good fidelity in an ultrabroad wavelength band from 1.2 to 1.9 µm, and the high degree of integrability, easy fabrication and multifunction make the CN-shaped WP pixels a promising candidate in optical device miniaturization, quantum applications and imaging technologies.

Rainfall and freeze-thaw landslides are common occurrences on southeastern Tibet Plateau; however, it can be difficult to categorize them via field surveys. Landslide classification can be determin...

Recently, multidimensional metasurfaces, which can modulate multiple optical parameters of input and output lights simultaneously, have aroused intensive interest. Here, we demonstrate multidimensional switchable images and 3D integrated beam splitters based on hyperbolic metamaterials (HMMs). On one hand, a switchable image controlled by output helicity and input wavelengths is achieved by arranging HMMs with different polarization conversion performance. On the other hand, polarization-multiplexed broadband beam splitter is generated by spatially engineering the subunit with broadband half-plate performance. By integrating the multiplexed beam splitter with a filter metamaterial, this multidimensional beam splitter can further realize the separation of output light by space and wavelength. This cascaded multilayer metamaterial achieves a brand new optical functionality and offers more inspiring possibilities for the design of multifunctional optical devices in the future.

Nucleation, significantly influenced by local structures in metallic melts, is crucial for controlling the microstructure of solidified materials. However, the connection between local atomic struc...

Electric vehicles (EVs) are considered a promising alternative to conventional vehicles (CVs) to alleviate the oil crisis and reduce urban air pollution and carbon emissions. Consumers usually focus on the tangible cost when choosing an EV or CV but overlook the time cost for restricting purchase or driving and the environmental cost from gas emissions, falling to have a comprehensive understanding of the economic competitiveness of CVs and EVs. In this study, a life cycle cost model for vehicles is conducted to express traffic and environmental policies in monetary terms, which are called intangible cost and external cost, respectively. Battery electric vehicles (BEVs), fuel cell electric vehicles (FCEVs), and CVs are compared in four first-tier, four new first-tier, and 4 s-tier and below cities in China. The comparison shows that BEVs and FCEVs in most cities are incomparable with CVs in terms of tangible cost. However, the prominent traffic and environmental policies in first-tier cities, especially in Beijing and Shanghai, greatly increase the intangible and external costs of CVs, making consumers more inclined to purchase BEVs and FCEVs. The main policy benefits of BEVs and FCEVs come from three aspects: government subsidies, purchase and driving restrictions, and environmental taxes. With the predictable reduction in government subsidies, traffic and environmental policies present important factors influencing the competitiveness of BEVs and FCEVs. In first-tier cities, BEVs and FCEVs already have a competitive foundation for large-scale promotion. In new first-tier and second-tier and below cities, stricter traffic and environmental policies need to be formulated to offset the negative impact of the reduction in government subsidies on the competitiveness of BEVs and FCEVs. Additionally, a sensitivity analysis reveals that increasing the mileage and reducing fuel prices can significantly improve the competitiveness of BEVs and FCEVs, respectively.

Since the edge-to-edge matching relationship of close-packed planes on an incoherent interphase boundary was found, the one-dimensional ledge migration mechanism has been put forward. However, owing to the lack of direct experimental evidence, the existence of the one-dimensional ledge is still questioned and it is thus usually treated as just an assumption. In this study, focusing on the existence of one-dimensional ledges and the migration mechanism of incoherent interphase boundaries, an atomic scale investigation on the migration of incoherent interphase boundaries in a body- to face-centered cubic transformation has been carried out using the phase-field crystal model. Simulation results demonstrated the presence of one-dimensional ledges on incoherent interphase boundaries, but only on those boundaries with high atomic densities. The simulation results further showed that the interphase boundaries with one-dimensional ledges migrate as a result of the nucleation and extension of the one-dimensional ledge, similar to the mechanism for two-dimensional ledges; meanwhile the interphase boundaries without one-dimensional ledges migrate according to a continuous mechanism by random atomic jumping. Because it is difficult for one-dimensional ledges to nucleate under low driving forces, interphase boundary migration based on the one-dimensional ledge mechanism is slower than that based on the continuous mechanism. This study reveals the structures and mechanisms of complex transitions of incoherent interphase boundaries and can aid a deeper understanding of solid phase transformations.

Kirigami, with facile and automated fashion of three-dimensional (3D) transformations, offers an unconventional approach for realizing cutting-edge optical nano-electromechanical systems. Here, we demonstrate an on-chip and electromechanically reconfigurable nano-kirigami with optical functionalities. The nano-electromechanical system is built on an Au/SiO2/Si substrate and operated via attractive electrostatic forces between the top gold nanostructure and bottom silicon substrate. Large-range nano-kirigami like 3D deformations are clearly observed and reversibly engineered, with scalable pitch size down to 0.975 μm. Broadband nonresonant and narrowband resonant optical reconfigurations are achieved at visible and near-infrared wavelengths, respectively, with a high modulation contrast up to 494%. On-chip modulation of optical helicity is further demonstrated in submicron nano-kirigami at near-infrared wavelengths. Such small-size and high-contrast reconfigurable optical nano-kirigami provides advanced methodologies and platforms for versatile on-chip manipulation of light at nanoscale., The authors present on-chip and electromechanically reconfigurable nanokirigami with optical functionalities. 3D deformations are achieved via attractive electrostatic forces between a gold nanostructure layer and silicon substrate, resulting in optical reconfigurations with high modulation contrast and small unit size.

An intrinsic challenge of the Li metal anode (LMA) that hinders its application is the formation of an unstable solid electrolyte interphase (SEI), which causes uncontrollable Li plating/stripping and deteriorates the cycling stability. While it is desirable to fabricate a robust artificial SEI to stabilize Li, it remains highly challenging to manipulate the composition of the protective film with high precision. Herein, we report a functional ‘gradient coating’ of mechanically enhanced hybrid inorganic–organic polyurea achieved by molecular layer deposition (MLD) for highly stable LMAs. The electrically insulating polymer on the coating surface can confine the electro-deposition of Li and tolerate the volume change due to its good flexibility, while the inner inorganic lithiophilic sites can effectively facilitate and regulate uniform Li nucleation and deposition. Owing to this elaborate interphase design, the protected Li can extend the cycling life significantly at a high current density of 6 mA cm−2. Furthermore, as a proof of concept for application in Li metal batteries (LMBs), stable cycling for over 1500 hours in Li–O2 batteries was achieved. This work demonstrates an innovative nano-scale protective film design for LMAs and creates new opportunities for the realization of high performance next-generation batteries.

Vehicle detection systems play a significant role in intelligent transportation systems (ITSs). At present, vehicle detection is realized either by very costly inductive loops, by video cameras that require good weather conditions and high computing resources, or by recently developed magnetic sensors that only obtain limited detection accuracy in congested traffic conditions. To overcome these challenges, this paper develops a passive radar system that is robust to bad weather conditions, low cost and radio silent for vehicle detection. The device is installed at the side of the road under crowded traffic conditions. In the developed system, cross-correlation (CC) operation is applied to obtain suboptimal detection gain and computational complexity. To decrease the impact of interference that is independently and identically distributed (i.i.d.) across isolated frequency channels and that of the Doppler effect produced by a mobile vehicle, a multichannel joint detection scheme based on multichannel fusion (MCF) is proposed and implemented. Furthermore, to achieve high resolution, an illuminator of opportunity (IO) with wide bandwidth is selected, and the system is then designed to receive a digital video broadcast-satellite (DVB-S) signal with a bandwidth of 37.5 MHz over multiple channels simultaneously. Simulation results show that the proposed MCF achieves better performance than the single-channel-based CC, and the advantage can be enhanced by increasing the number of channels for joint detection. Field test results further verify the novelty of the MCF and the developed passive radar prototype.

The key to achieving high efficiencies, high performance, and low costs of adsorption heat pumps/chillers (AHPs/ACs) is to choose a suitable adsorbent. A computational screening of 6013 computation-ready experimental metal–organic frameworks (CoRE-MOFs) is performed for methanol–MOF pairs in AHPs/ACs, and 137 953 hypothetical MOFs (hMOFs) are further directionally screened based on the range of optimal CoRE-MOF descriptors. Compared with the blind screening of CoRE-MOFs (∼13%), ∼80% of hMOFs obtained by the directional screening exhibited high performance in AHPs/ACs, proving the effectiveness of directional screening. Then, the techno-economic analysis (Ctotal) of AHPs/ACs for each MOF was performed based on the equipment cost (Cequipment), cycle cost (Ccycle), and material cost (CMOF). Cequipment accounted for the greatest proportion of Ctotal, but the proportion of Cequipment decreased and the proportion of Ccycle gradually increased as the MOF data set tended to be the materials with better performance. This confirmed the reduction of Ctotal by an effective enhancement of the Ccycle proportion, and that the high manufacturing cost of MOFs would not restrict their widespread use in AHPs/ACs. Among 6 machine learning (ML) algorithms, the random forest could yield the best prediction effect with little effect by the metal type of MOFs, whereas the heat of adsorption and MOF density were two key descriptors to determine Ctotal. 12 lowest-cost CoRE-MOFs and hMOFs were identified for each application, and their average costs in state 2 were only ∼1 USD kJ−1 in AHPs/ACs. Finally, a variant of the well-known MOF (Cu3BTC2) was predicted to possess superior techno-economy, which was confirmed by a parallel methanol adsorption experiment. These comprehensive insights from directional computational screening, ML algorithms to experiment can guide the development of low-cost and high-performance MOFs for AHPs/ACs in a variety of energy conservation and industrial applications.

Antiferroelectric materials are proposed as a potential solution to achieve multi-state memories, but the fundamental physical mechanism underlying the memory effect still needs to be clarified. Here, we study the memory effect in a typical antiferroelectric ceramic of Pb0.99Nb0.02[(Zr0.6Sn0.4)0.95Ti0.05]0.98O3 by systematically analyzing various hysteresis loops of polarization intensity and current density vs. electric field, where the kinetic behaviors are concerned about for the first time. The parallel pre-poling electric field reduces the critical electric field of antiferroelectric-ferroelectric phase transition, while the antiparallel field increases it. The memory behavior is significantly enhanced with the increasing of pre-poling time, but exhibits a remarkable weakening with the relaxation time increasing. It is a combined effect of electric-field-induced preferentially oriented antiferroelectric domains and internal bias electric field. This work not only improves comprehending in memory effect in antiferroelectric materials, but also enlightens the deeper understanding of other physical properties related to field-induced phase transitions.

In conventional fast-ramp-based target detection schemes for the frequency modulated continuous wave (FMCW) radar systems, all chirp sequences are performed fully on two-dimensional fast Fourier transforms (FFTs) to estimate range and velocity of a target, and all range-Doppler cells are scanned by the two-dimensional (2-D) cell-averaging constant false alarm rate (CA-CFAR) detector to extract valid targets against background noise. This results in an extremely high computational complexity. To decrease the complexity while maintaining a desired performance, this article proposes a target detection scheme based on distributed one-dimensional (1-D) CA-CFAR and region-of-interest (ROI) preprocessing, which performs Doppler-FFT only for range ROI cells and scans only Doppler ROI cells to extract pretargets. Simulation results indicate that the proposed scheme significantly decreases complexity and simultaneously improves detection performance in terms of detection probability, figure of merit (FoM), and CFAR loss, as compared with the conventional schemes. The advantages of the proposed scheme over the conventional ones are further verified by field tests under multitarget scenario, using our recently developed FMCW radar with high angular resolution.

Hepatic-arterial infusion (HAI) of low-density lipoprotein (LDL) nanoparticles reconstituted with docosahexaenoic acid (DHA) (LDL-DHA) has been shown in a rat hepatoma model to be a promising treatment for hepatocellular carcinoma. To date, little is known regarding the safety of HAI of LDL-DHA to the liver. Therefore, we aimed to investigate the deposition, metabolism and safety of HAI of LDL-DHA (2, 4 or 8 mg/kg) in the rat. Following HAI, fluorescent labeled LDL nanoparticles displayed a biexponential plasma concentration time curve as the particles were rapidly extracted by the liver. Overall, increasing doses of HAI of LDL-DHA was well tolerated in the rat. Body weight, plasma biochemistry and histology were all unremarkable and molecular markers of inflammation did not increase with treatment. Lipidomics analyses showed that LDL-DHA was preferentially oxidized to the anti-inflammatory mediator, protectin DX. We conclude that HAI of LDL-DHA nanoparticles is not only safe, but provides potential hepatoprotective benefits.

Artificial nanostructures, whose spatial symmetry can be arbitrarily designed, play an ever more critical role for the realization of giant chiral optical responses. In order to break the mirror sy...

The development of high-performance sulfide electrolyte-based all-solid-state lithium-ion batteries (ASSLIBs) has been inhibited by problematic ionic transport and side reactions at the cathode interface, and their success is dependent on the functionalized interface upon charging and discharging. Despite recent progresses, it has proven challenging to design a favorable interface that can suppress the side reactions and enable smooth motion of Li+ ions. Herein, a favorable Zr-based cathode interface is elaborately manipulated by the atomic layer deposition (ALD) for sulfide-based ASSLIBs. Flexile control over the Li sub-cycle during the preparation process is demonstrated to be crucial for achieving a robust cathode interface with a desirable Li+ ionic conductivity. The ASSLIBs equipped with this functional interface exhibit excellent cycling stability and rate capability at room temperature (RT). Various electrochemical and spectroscopic characterizations reveal that the ionic conductive interface can significantly limit side reactions and induce a low polarization of the (de)intercalation toward cathode materials. The interfacial manipulation regarding ionic conductivity and structure realized by ALD provides a new strategy to achieve high-performance ASSLIBs.

In the robotic polishing system for the wheel hubs, initial point alignment is a very important procedure before the robot starts to polish. Since the surface shapes of the wheel hubs are complex, traditional contact sensors are not suitable for the initial point alignment. Therefore, this paper presents a vision-based initial point alignment control method due to the merits of non-contact and high precision of the vision sensor. The main procedures of the new proposed initial point alignment methods are as follows. Firstly, the center point of the wheel hub is computed based on the growth of sampled points (GSP) method. Secondly, the center lines of the spokes of the wheel hub are extracted based on the edges of the spokes. Based on the center point and the center lines of the spokes, the needed rotation angle of the wheel hub denoting the current and target initial points can be computed. Thirdly, an alignment controller is designed to align the current initial point with the target one. Finally, experiments are well conducted to demonstrate the effectiveness of the proposed initial point alignment control method for the wheel hubs.

Improving the lithium density and performance of lithium-based ceramics is the main direction for the development of advanced tritium breeder. In this work, the previously used polymers or organics were replaced by eutectic LiNO3–LiCl in wet process for preparing spherical green body, and then Li4SiO4 pebbles were fabricated through molten salt assisted sintering. The eutectic salt used herein was eco-friendly and had little effect on the Li4SiO4 pebbles. Instead, the incorporation of eutectic salt improved the lithium density and sinterability of Li4SiO4. The prepared Li4SiO4 pebbles exhibited well-grained microstructure, and the grain size increased with the increasing contents of eutectic salt. Compressive tests showed that the crush load increased more than five times when 20 wt% eutectic salt was added. The proposed method may have great prospects in the preparation of tritium breeding materials.

Traditional hydrogen production is primarily based on coal gasification in China, and it faces severe challenges relating to its high energy consumption and carbon emissions. Coke oven gas-based hydrogen (COGH) promises to be a potential alternative route for producing coal gasification-based hydrogen (CGH) due to the large-scale coking industry in China. Therefore, it is imperative to understand which route is better. In this study, a life cycle model is developed to compare the energy consumption, carbon emissions and economic cost of the two routes. The model boundary covers all processes from raw material extraction to hydrogen production. Four allocation scenarios (viz. market value allocation, mass allocation, energy allocation and no allocation) are considered to address the burden allocation between various products involved in the coal coking process. Furthermore, the effects of variations in several key parameters on the performance of the two routes are investigated through a sensitivity analysis. The results show that COGH has better technical, environmental and economic performance than CGH. The energy consumption, carbon emissions, capital expenditure and operating expenditure of COGH are 34.6%, 36.7%, 27.4% and 8.7% lower than those of CGH, while the profit and internal rate of return of COGH are 1.35 and 2.33 times those of CGH. Aside from no allocation, market value allocation is most favourable for COGH in view of its reduced energy consumption and carbon emissions. Compared with CGH, COGH has much stronger economic competitiveness in the face of raw material price fluctuations. This alternative route has broad development prospects because of its excellent comprehensive performance and large-scale industrial base, while efficiency improvements and energy savings should always be considered. The results provide a comprehensive and valuable basis for comparing the strengths and weaknesses of the two routes and to help policymakers take measures to promote the development of the hydrogen production industry.

This paper aims to discuss an environmental, social, and economic analysis of energy utilization of crop residues from life cycle perspectives in China. The methodologies employed to achieve this objective are environmental life cycle assessment (E-LCA), life cycle cost (LCC), and social life cycle assessment (S-LCA). Five scenarios are developed based on the conversion technologies and final bioenergy products. The system boundaries include crop residue collection, transportation, pre-treatment, and conversion process. The replaced amounts of energy are also taken into account in the E-LCA analysis. The functional unit is defined as 1 MJ of energy produced. Eight impact categories are considered besides climate change in E-LCA. The investment capital cost and salary cost are collected and compared in the life cycle of the scenarios. Three stakeholders and several subcategories are considered in the S-LCA analysis defined by UNEP/ SETAS guidelines. The results show that the energy utilization of crop residue has carbon emission factors of 0.09–0.18 kg (CO2 eq per 1 MJ), and presents a net carbon emissions reduction of 0.03–0.15 kg (CO2 eq per 1 MJ) compared with the convectional electricity or petrol, but the other impacts should be paid attention to in the biomass energy scenarios. The energy utilization of crop residues can bring economic benefit to local communities and the society, but the working conditions of local workers need to be improved in future biomass energy development.

Hydrogel-based strain sensors have been widely investigated owing to their intrinsic flexible and extensible properties. However, integrating good mechanical properties and excellent strain sensitivity into one hydrogel remains a challenge. In this work, a dual physical cross-linked carboxymethyl cellulose-Fe3+/polyacrylamide (CMC-Fe3+/PAAm) double network hydrogel was developed by facile two-step method. In this hydrogel, the Fe3+ cross-linked CMC acts as the first network for dissipating energy and hydrophobic association PAAm acts as the second network to maintain the integrity of hydrogel. Owing to these physical interactions, the as-prepared hydrogel shows good mechanical properties (e.g., tensile strength, 1.82 MPa; toughness, 6.52 MJ/m3). Furthermore, these mechanical behaviors can be modulated by adjusting the solid content, CMC/PAAm ratio, Fe3+ concentration and soaking time in Fe3+ solution. Moreover, the obtained hydrogel shows excellent self-recovery and anti-fatigue property due to the reversibility of dual physical cross-linked interactions. Additionally, the CMC-Fe3+/PAAm hydrogel shows good conductivity (1.82 S/m), strain sensitivity (gauge factor = 4.02 at 50–600% strain), and fast response time (260 ms). Based on the high strain sensitivity, the CMC-Fe3+/PAAm hydrogel can fabricate a flexible strain sensor for precisely monitoring various human motions. This study suggests that the CMC-Fe3+/PAAm hydrogel exhibits potential application in the flexible and stretchable strain sensors.

PurposeThis study aims to explore the innovative capabilities of building information modeling (BIM) in construction projects. The objectives are to construct an inclusive conceptual framework of BIM-enabled construction innovation, identify the status and trends of innovation-related research in BIM publications, synthesize research pertaining to BIM-enabled construction innovation and discover core research requirements in the related body of knowledge.Design/methodology/approachThis study proposes a comprehensive theoretical framework, named innovation pyramid, comprising context, actor, artifact, process, structure and innovative task for exploring and analyzing the innovative capability of BIM in construction projects. Accordingly, mixed methods were used to perform a systematic review of research on the topic of BIM-enabled construction innovation.FindingsThe findings reveal that BIM innovation-related articles have predominantly considered BIM as an innovation from a technological standpoint, while the innovative capabilities of BIM have remained under-researched with a fragmented research focus. Fertile grounds for research have emerged and call for research pertaining to entities of “structure” and “innovative task” as well as interaction, interrelations and mutually adjusting effect among the entities.Practical implicationsThe framework proposed may be useful for subsequent research design and for assisting project management practitioners in the use of BIM to achieve innovation more efficiently.Originality/valueThis research provides an insight into the innovative capabilities of BIM based on the BIM–collaboration–construction innovation logic chain. It contributes to the body of knowledge by devising an inclusive conceptual framework of BIM-enabled construction innovation, synthesizing the state of the art and exposing the research needs in this area.

The interactions of photonic spin angular momentum and orbital angular momentum, i.e., the spin-orbit coupling in focused beams, evanescent waves or artificial photonic structures, have attracted intensive investigations for the unusual fundamental phenomena in physics and potential applications in optical and quantum systems. It is of fundamental importance to enhance performance of spin-orbit coupling in optics. Here, we demonstrate a titanium dioxide (TiO2)–based all-dielectric metasurface exhibiting a high efficient control of photonic spin Hall effect (PSHE) in a transmissive configuration. This metasurface can achieve high-efficiency symmetric spin-dependent trajectory propagation due to the spin-dependent Pancharatnam-Berry phase. The as-formed metadevices with high-aspect-ratio TiO2 nanofins are able to realize (86%, measured at 514 nm) and broadband PSHEs in visible regime. Our results provide useful insights on high-efficiency metasurfaces with versatile functionalities in visible regime.

A series of Ti-(38-2x)Nb-xMo (wt.%) alloys are designed using 1% Mo to replace 2% Nb in order to gradually increase the β stability and obtain a low springback. The α″ phase is exhibited in Ti-38Nb and suppressed with an increasing Mo content. The Ti-38Nb and Ti-34Nb-2Mo alloys show stress-induced α″ martensite transformations during cold rolling and double yielding behavior in tensile tests. The Ti-30Nb-4Mo and Ti-26Nb-6Mo alloys exhibit nonlinear deformation owing to the metastable β phase. With an increase in the Mo content, Young’s modulus increases slightly from 68 GPa in Ti-38Nb to 73 GPa in Ti-26Nb-6Mo, owing to the increase in β stability. Mo shows a solution strengthening effect that gradually increases the tensile strength. Although a higher Young’s modulus was not observed to be induced through deformation in Ti-(38-2x)Nb-xMo alloys, low springback was obtained according to the three-point bending loading–unloading test. In particular, the Ti-38Nb and Ti-34Nb-2Mo alloys with stress-induced α″ martensite transformations exhibit low yielding stress and are thus easily deformed. The deformed α″ phase hardly reverts to the β matrix after unloading, and therefore, the plastic deformation is maintained.

In this work, magneto-Raman mapping was performed on monolayer MoS2 at 4 K, which exhibited a prominent magnetic field-induced modulation of phonon intensity. Interestingly, structural microinhomog...

Intra-peritoneal adhesion are common and serious complications after surgery. Deposition of proteins and inflammatory response on injured cecum are main factors resulting in the formation of adhesi...

Nanoscale Kirkendall effect has been widely used for rationally fabricating high-quality hollow nanocrystals, but often requires the intrinsic diffusion coefficient of out-diffusion materials higher than that of in-diffusion components. Here we demonstrate an unexpected Kirkendall effect that occurs in diffusing intrinsically faster Cu atoms into Pd icosahedra, leading to the formation of PdCu alloyed hollow nanocrystals. The control experiment with Pd octahedra replacing icosahedra indicates the critical role of twin boundaries in facilitating such unexpected Kirkendall effect. In addition, geometric phase analysis and density functional theory calculation show that out-diffusion of Pd atoms in the icosahedra is faster than in-diffusion of Cu atoms, particularly through the twin boundaries, upon the strain gradient with an inward distribution from tensile to compressive strains. The unexpected Kirkendall effect is also found in the interdiffusion of Ag and Pd atoms in Pd icosahedra. Our finds break the limitation of the intrinsic diffusion coefficient for the synthesis of hollow nanocrystals through Kirkendall effect and are expected to enormously enrich the family of hollow nanocrystals which have shown great potential in broad areas, such as fine chemical production, energy storage and conversion, and environmental protection. This work also provides a deep understanding in the diffusion behavior of atoms upon the strain gradient.

Black phosphorus (BP) has recently attracted intense research interest due to its unique thickness-dependent and anisotropic electronic and photonic properties, and has shown promising potential in nanophotonic, nanoelectronics and energy storage applications. However, the application of BP in practical devices is hindered by its high commercial cost. To further reduce the cost and accelerate the development of BP, a highly efficient preparation strategy for low-cost BP must be found. Herein, we report such a method via a modified chemical vapor transport (CVT) method by replacing high-purity red phosphorus (RP) with a low-purity precursor counterpart. We show that this method can drastically reduce the cost of manufacturing by several orders of magnitude. Furthermore, the BP produced using low-cost RP shows nearly the same crystal quality, high purity, local chemical structure, and electronic properties, compared with those of the high-cost BP prepared by the traditional CVT method. Most importantly, exfoliated phosphorene nanosheets prepared from the low-cost BP exhibit promising hydrogen evolution reaction (HER) activity. Owing to the high quality and high conversion efficiency, the low-cost BP holds promising potential in future scientific research and industrial applications.

Complex oxides show extreme sensitivity to structural distortions and defects, and the intricate balance of competing interactions which emerge at atomically defined interfaces may give rise to unexpected physics. In the interfaces of non-magnetic complex oxides, one of the most intriguing properties is the emergence of magnetism which is sensitive to chemical defects. Particularly, it is unclear which defects are responsible for the emergent magnetic interfaces. Here, we show direct and clear experimental evidence, supported by theoretical explanation, that the B-site cation stoichiometry is crucial for the creation and control of magnetism at the interface between non-magnetic ABO3-perovskite oxides, LaAlO3 and SrTiO3. We find that consecutive defect formation, driven by atomic charge compensation, establishes the formation of robust perpendicular magnetic moments at the interface. Our observations propose a route to tune these emerging magnetoelectric structures, which are strongly coupled at the polar-nonpolar complex oxide interfaces., In the interfaces of non-magnetic complex oxides, it is unclear which defects are responsible for the magnetic interfaces. Here, the authors find the B-site cation stoichiometry is crucial for the creation and control of magnetism at the interface between non-magnetic ABO3-perovskite oxides.

The multicomponent L12 phase in high entropy alloys (HEAs) has shown excellent thermal stability. However, the understanding of its intrinsic origins is limited to the Lifshitz-Slyozov-Wagner (LSW) theory. In the present study, we investigate the influence of lattice misfit, which is not considered in LSW theory, on the coarsening kinetics of the multicomponent L12 phase. Different from that in most traditional alloys, the coarsening constant of multicomponent L12 particles decreases with the increasing lattice misfit in HEAs. This finding provides a new view for understanding the sluggish coarsening kinetics of L12 phase in HEAs.

Water splitting has been proposed to be a promising approach to producing clean hydrogen fuel. The two half‐reactions of water splitting, that is, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), take place kinetically fast in solutions with completely different pH values. Enabling HER and OER to simultaneously occur under kinetically favorable conditions while using exclusively low‐cost, earth‐abundant electrocatalysts is highly desirable but remains a challenge. Herein, we demonstrate that using a bipolar membrane (BPM) we can accomplish HER in a strongly acidic solution and OER in a strongly basic solution, with bifunctional self‐supported cobalt‐nickel phosphide nanowire electrodes to catalyze both reactions. Such asymmetric acid/alkaline water electrolysis can be achieved at 1.567 V to deliver a current density of 10 mA/cm2 with ca. 100% Faradaic efficiency. Moreover, using an “irregular” BPM with unintentional crossover the voltage needed to afford 10 mA/cm2 can be reduced to 0.847 V, due to the assistance of electrochemical neutralization between acid and alkaline. Furthermore, we show that BPM‐based asymmetric water electrolysis can be accomplished in a circulated single‐cell electrolyzer delivering 10 mA/cm2 at 1.550 V and splitting water very stably for at least 25 hours, and that water electrolysis is enabled by a solar panel operating at 0.908 V (@13 mA/cm2), using an “irregular” BPM. BPM‐based asymmetric water electrolysis is a promising alternative to conventional proton and anion exchange membrane water electrolysis.

Delivering therapeutic antibodies into the brain across the blood-brain barrier at a therapeutic level is a promising while challenging approach in the treatment of neurological disorders. Here, we present a polymeric nanomicelle (PM) system capable of delivering therapeutically effective levels of 3D6 antibody fragments (3D6-Fab) into the brain parenchyma for inhibiting Aβ aggregation. PM assembly was achieved by charge-converting 3D6-Fab through pH-sensitive citraconylation to allow complexation with reductive-sensitive cationic polymers. Brain targeting was achieved by functionalizing the PM surface with glucose molecules to allow interaction with recycling glucose transporter (Glut)-1 proteins. Consequently, 41-fold enhanced 3D6-Fab accumulation in the brain was achieved by using the PM system compared to free 3D6-Fab. Furthermore, therapeutic benefits were obtained by successfully inhibiting Aβ1-42 aggregation in Alzheimer's disease mice systemically treated with 3D6-Fab-loaded glucosylated PM. Hence, this nanocarrier system represents a promising method for effectively delivering functional antibody agents into the brain and treating neurological diseases.

Cd-containing polycrystalline Bi0.46Sb1.54Te3 samples with precisely controlled phase composition were synthesized by conventional melting-quenching-annealing technique and a melt-spinning method. ...

Strain engineering provides an important strategy to modulate the optical and electrical properties of semiconductors for improving devices performance with mechanical force or thermal expansion difference. Here, we present the investigation of the local strain distribution over few-layer MoS2 bubbles, by using scanning photoluminescence and Raman spectroscopies. We observe the obvious direct bandgap emissions with strain in the few-layer MoS2 bubble and the strain-induced continuous energy shifts of both resonant excitons and vibrational modes from the edge of the MoS2 bubble to the center (10 µm scale), associated with the oscillations resulted from the optical interference-induced temperature distribution. To understand these results, we perform ab initio simulations to calculate the electronic and vibrational properties of few-layer MoS2 with biaxial tensile strain, based on density functional theory, finding good agreement with the experimental results. Our study suggests that local strain offers a convenient way to continuously tune the physical properties of a few-layer transition metal dichalcogenides (TMDs) semiconductor, and opens up new possibilities for band engineering within the 2D plane.

A series of Ti-29Nb-(4, 7, 10, 13)Zr-2Cr alloys were fabricated to investigate the influence of Zr content on microstructures and mechanical properties. All the four alloys present a single β phase after solution treatment. With the increase in Zr content, the 0.2% proof stress is gradually increased from 388 MPa in Ti-29Nb-4Zr-2Cr to 713 MPa in Ti-29Nb-13Zr-2Cr. The Young’s modulus gradually is decreased from 80 GPa in Ti-29Nb-4Zr-2Cr to 63 GPa in Ti-29Nb-13Zr-2Cr. The elongation shows the same trend as that of Young’s modulus. The changes of mechanical properties are influenced by the β stability and solid solution strengthening effect, which are both enhanced by Zr addition. The Ti-29Nb-13Zr-2Cr alloy presents a Young’s modulus of 63 GPa, tensile strength of 730 MPa and elongation of 18% and is a promising biomedical material.

The synthesis of perovskite (ABO3) films with mixed anions has enabled us to constitute a novel class of materials exhibiting intriguing functionalities. In contrast to traditional metallic cation doping, anion doping within easy-to-prepare conditions usually gives rise to tremendous modulations of physical properties with tunable crystal structures. Here, oxyfluoride BaFeO3-xFy (BFO–F) thin films were successfully synthesized via a low-temperature reaction with polyvinylidene fluoride, which exhibit extremely structural stability over time. The existence of fluorine was confirmed by the combination of X-ray photoelectron depth profile and soft X-ray absorption spectroscopy. The oxyfluoride BFO–F films demonstrate a sequence of structural evolutions with reduced out-of-plane lattices, by means of elevating fluorination temperatures. The valence state of iron in BFO–F is gradually changed from 3+ to 4+ for higher fluorination temperatures. Moreover, the resistivity of BFO–F dramatically decreases, compared to that of pristine oxygen-deficient BaFeO3-δ film. Our results provide insight into the modulations on the structures and physical properties of perovskite oxyfluorides through the facile fluorination process and contribute to the fundamental understanding of fluorination.

Statistical model is a traditional safety diagnostic model for dam seepage. It can hardly display the nonlinear relationship between dam seepage and the load sets and has the disadvantage of poor extension prediction. In this paper, the theories of Back Propagation Neural Network (BPNN) combined with Genetic Algorithm (GA) are applied to the seepage prediction model. Taking a typical dam in China as an example, the prediction results of BPNN-GA model and statistical model are compared with the monitoring values. The results show that the improved dam seepage model enhances the ability of nonlinear mapping and generalization and makes the seepage prediction more accurate and reasonable in the near future. According to the established criterion, the safety state of the dam in flood season is evaluated.