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The electrochemical CO2reduction reaction (CO2RR) into high-value carbon compounds such as CO and HCOOH is a promising strategy for the utilization and conversion of emitted CO2. However, the selectivity of the CO2RR for HCOOH is typically less than 90% and operates within a narrow voltage range, which limits its practical application. Herein, we propose a novel heterostructural aerogel as a highly efficient electrocatalyst for CO2RR to HCOOH. This catalyst consists of Cu–Sn–Oxsolid solutions embedded in a reduced graphene oxide matrix (Cu–Sn–Ox/rGO). The incorporation of Cu2+into the SnO2matrix enhances HCOOH production by improving the adsorption of the *OCHO intermediate and inhibiting H2evolution, as confirmed by in situmeasurements and computational studies. As a result, Cu–Sn–Ox/rGO achieves a remarkable Faradaic efficiency (FE) of up to 91.4% for HCOOH and maintains high selectivity over a broad operating voltage range (−0.8 to −1.1 V). Additionally, the assembled Zn–CO2batteries demonstrated an excellent power density of 1.14 mW/cm2and exceptional stability for over 25 h.

An inner Helmholtz plane (IHP) structure regulation strategy can be achieved by low-cost and non-toxic maltitol additive; hence the HER, corrosive, and dendrite issues in aqueous Zn-based batteries have been effectively restrained.

Excitonic insulators are long-sought-after quantum materials predicted to spontaneously open a gap by the Bose condensation of bound electron–hole pairs, namely, excitons, in their ground state. Since the theoretical conjecture, extensive efforts have been devoted to pursuing excitonic insulator platforms for exploring macroscopic quantum phenomena in real materials. Reliable evidence of excitonic character has been obtained in layered chalcogenides as promising candidates. However, owing to the interference of intrinsic lattice instabilities, it is still debatable whether those features, such as the charge density wave and gap opening, are primarily driven by the excitonic effect or by the lattice transition. Herein, we develop an intercalation chemistry strategy for obtaining a novel charge-transfer excitonic insulator in organic–inorganic superlattice interfaces that serves as an ideal platform to decouple the excitonic effect from the lattice effect. In this system, we observe a narrow excitonic gap, formation of a charge density wave without periodic lattice distortion, and metal–insulator transition, providing visualized evidence of exciton condensation occurring in thermal equilibrium. Our findings identify self-assembly intercalation chemistry as a new strategy for developing novel excitonic insulators.

The development of an ultralow-Pt catalyst layer (CL) without sacrificing proton-exchange membrane (PEM) fuel cell performance and durability is urgently needed to boost fuel cell commercialization. Besides material development, advanced CL microstructure design is required to ensure optimal multi-physics transfer and enhanced electrochemical surface area (ECSA). However, this is largely hindered by current poor understanding of the complex “gas-liquid-heat-electron-proton” transfers, in conjunction with the electrochemical reactions, and is also greatly influenced by the temporal CL microstructure evolution during long-term operation. Herein, we present several important research and development directions after critically examining the multi-physics transfer in fresh CLs and the microstructure evolution of degraded CLs. This knowledge is essential to designing and fabricating ultralow-Pt CLs for next-generation cost-effective, high-performance, and durable PEM fuel cells and to meet the urgent need for development of new research tools, including pore- and cell-scale models, experimental methods, machine learning algorithms, and their rational combinations.

Thepotential of organic semiconductors(OSC) in forming power devices has been preliminarily demonstrated recently for their high breakdown performance. As one kind of narrow bandwidth semiconductor, the application of which in the power realm is also limited by its sensitivity to ambient temperature and self-heating effect. In this letter, the thermal stability of breakdown characteristics in the lateral drift region organic field transistor(LDR-OFET) is quantitatively and qualitatively explored. By employing the simple spin-coating process, the fabricated LDR-OFETs consist of a diketopyrrolopyrrole-based polymer(DPPT-TT) layer and a Poly (methyl methacrylate)(PMMA) layer as the semiconductor active layer and insulator layer, respectively. Based on the fabricated devices, the good thermal stability of OSC-based lateral power devices is observed. For the temperature ranges from 300-450K, neither the ambient temperature fluctuation nor the self-heating effect results in thermal runaway, making the copolymer OSC-based power devices capable of maintaining their off-state breakdown performance in a wide temperature range. Such a stable avalanche-like breakdown performance indicates the outstanding potential of OSC-based devices in the power realm.

Ultrasensitive sensing to trace atomic and molecular analytes has gained interest for its intimate relation to industrial sectors and human lives. One of the keys to ultrasensitive sensing for many analytical techniques lies in enriching trace analytes onto well-designed substrates. However, the coffee ring effect, nonuniform distribution of analytes onto substrates, in the droplet drying process hinders the ultrasensitive and stable sensing onto the substrates. Here, we propose a substrate-free strategy to suppress the coffee ring effect, enrich analytes, and self-assemble a signal-amplifying (SA) platform for multimode laser sensing. The strategy involves acoustically levitating and drying a droplet, mixed with analytes and core–shell Au@SiO2nanoparticles, to self-assemble an SA platform. The SA platform with a plasmonic nanostructure can dramatically enrich analytes, enabling enormous spectroscopic signal amplification. Specifically, the SA platform can promote atomic detection (cadmium and chromium) to the 10–3mg/L level by nanoparticle-enhanced laser-induced breakdown spectroscopy and can promote molecule detection (rhodamine 6G) to the 10–11mol/L level by surface-enhanced Raman scattering. All in all, the SA platform, self-assembled by acoustic levitation, can intrinsically suppress the coffee ring effect and enrich trace analytes, enabling ultrasensitive multimode laser sensing.

Currently, the development of calcium-ion batteries (CIBs) is still in its infancy and greatly plagued by the absence of satisfactory cathode materials and compatible electrolytes. Herein, an acetonitrile–water hybrid electrolyte is first developed in CIB chemistry, in which, the strong lubricating and shielding effect of water solvent significantly boosts the swift transport of bulky Ca2+, thus contributing to large capacity storage of Ca2+in layered vanadium oxides (Ca0.25V2O5·nH2O, CVO). Meanwhile, the acetonitrile component noticeably suppresses the dissolution of vanadium species during repeated Ca2+-ion uptake/release, endowing the CVO cathode with a robust cycle life. More importantly, spectral characterization and molecular dynamics simulation confirm that the water molecules are well stabilized by the mutual hydrogen bonding with acetonitrile molecules (O–H···N), endowing the aqueous hybrid electrolyte with high electrochemical stability. By using this aqueous hybrid electrolyte, the CVO electrode shows a high specific discharge capacity of 158.2 mAh g–1at 0.2 A g–1, an appealing capacity of 104.6 mAh g–1at a high rate of 5 A g–1, and a capacity retention of 95% after 2000 cycles at 1.0 A g–1, which is a record-high performance for CIBs reported so far. A mechanistic study exemplifies the reversible extraction of Ca2+from the gap of VO polyhedral layers, which are accompanied by the reversible V–O and V–V skeleton change as well as reversible variation of layer spacing. This work constitutes a major advance in developing high-performance Ca-ion batteries.

Aerial access networks have been envisioned as a promising 6G solution to enhance the ground communication systems in both coverage and capacity. To better utilize the spectrum and fully explore different channel characteristics, this paper constructs an integrated network comprising the High Altitude Platform (HAP) and Unmanned Air Vehicles (UAVs) with the Non-Orthogonal Multiple Access (NOMA) technology. In order to improve the transmission quality of images and videos, a power management scheme is proposed to minimize the distortion of the transmissions from the HAP and UAVs to the terminals. The power control is formulated as a non-convex problem constrained by the maximal transmit power and the minimal terminal rate requirements. The variable substitution and the first-order Tailor’s expansion is used to transform it into a sequence of convex problems, which are subsequently solved through the gradient projection method. Simulation demonstrates the signal distortion and error rate improvement achieved by the proposed algorithm.

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Embedded memory, which heavily relies on the manufacturing process, has been widely adopted in various industrial applications. As the field of embedded memory continues to evolve, innovative strategies are emerging to enhance performance. Among them, resistive random access memory (RRAM) has gained significant attention due to its numerous advantages over traditional memory devices, including high speed (<1 ns), high density (4 F2·n−1), high scalability (∼nm), and low power consumption (∼pJ). This review focuses on the recent progress of embedded RRAM in industrial manufacturing and its potential applications. It provides a brief introduction to the concepts and advantages of RRAM, discusses the key factors that impact its industrial manufacturing, and presents the commercial progress driven by cutting-edge nanotechnology, which has been pursued by many semiconductor giants. Additionally, it highlights the adoption of embedded RRAM in emerging applications within the realm of the Internet of Things and future intelligent computing, with a particular emphasis on its role in neuromorphic computing. Finally, the review discusses the current challenges and provides insights into the prospects of embedded RRAM in the era of big data and artificial intelligence.

As a typical correlated metal oxide, vanadium dioxide (VO2) shows specific metal–insulator transition (MIT) properties and demonstrates great potential applications in ultrafast optoelectronic switch, resistive memory, and neuromorphic devices. Effective control of the MIT process is essential for improving the device performance. In the current study, we have first proposed a photoassisted ion-doping method to modulate the phase transition of the VO2layer based on the photovoltaic effect and electron–ion synergic doping in acid solution. Experimental results show that, for the prepared n-VO2/p-GaN nanojunction, this photoassisted strategy can effectively dope the n-VO2layer by H+, Al3+, or Mg2+ions under light radiation and trigger consecutive insulator–metal–insulator transitions. If combined with standard lithography or electron beam etching processes, selective doping with nanoscale size area can also be achieved. This photoassisted doping method not only shows a facile route for MIT modulation via a doping route under ambient conditions but also supplies some clues for photosensitive detection in the future.

Miscanthus, a member of the Saccharinae subtribe that includes sorghum and sugarcane, has been widely studied as a feedstock for cellulosic biofuel production. Here, we report the sequencing and assembly of the Miscanthus floridulusgenome by the integration of PacBio sequencing and Hi-C mapping, resulting in a chromosome-scale, high-quality reference genome of the genus Miscanthus. Comparisons among Saccharinae genomes suggest that Sorghumsplit first from the common ancestor of Saccharumand Miscanthus, which subsequently diverged from each other, with two successive whole-genome duplication events occurring independently in the Saccharumgenus and one whole-genome duplication occurring in the Miscanthusgenus. Fusion of two chromosomes occurred during rediploidization in M. floridulusand no significant subgenome dominance was observed. A survey of cellulose synthases (CesA) in M. floridulusrevealed quite high expression of most CesAgenes in growing stems, which is in agreement with the high cellulose content of this species. Resequencing and comparisons of 75 Miscanthusaccessions suggest that M. lutarioripariusis genetically close to M. sacchariflorusand that M. floridulusis more distantly related to other species and is more genetically diverse. This study provides a valuable genomic resource for molecular breeding and improvement of Miscanthusand Saccharinae crops.

•A STSF configuration is proposed as the cathode flow field of AC-PEMFC.•A 3D multiphase model is applied and validated against the experiment.•The STSF improves the water content by reducing the internal temperature.•A superior output voltage and mass-specific power density are achieved.

The work presents the VUV-UV-vis photoluminescence of Ba3La(PO4)3:Ln3+ (Ln = Tb, Eu) prepared by a high-temperature solid-state reaction route. The excitation and emission spectra, the fluorescence decays and the time-resolved emission spectra were measured and discussed in detail. The results revealed that Tb3+ can efficiently transfer excitation energy to Eu3+ via its 5d and 4f states and therefore sensitizes Eu3+ emission under VUV-UV excitation, results in tunable emission in a large color gamut.

The efficient generation and active modulation of terahertz (THz) waves are strongly required for the development of various THz applications such as THz imaging/spectroscopy and THz communication. In addition, due to the increasing degree of integration for the THz optoelectronic devices, miniaturizing the complex THz system into a compact unit is also important and necessary. Today, integrating the THz source with the modulator to develop a powerful, easy-to-adjust, and scalable or on-chip THz emitter is still a challenge. As a new type of THz emitter, a spintronic THz emitter has attracted a great deal of attention due to its advantages of high efficiency, ultrawide band, low cost, and easy integration. In this study, we have proposed a multifield-modulated spintronic THz emitter based on the VO2/Ni/Pt multilayer film structure with a wide band region of 0–3 THz. Because of the pronounced phase transition of the integrated VO2layer, the fabricated THz emitter can be efficiently modulated via thermal or electric stimuli with a modulation depth of about one order of magnitude; the modulation depths under thermal stimulation and electrical stimulation were 91.8% and 97.3%, respectively. It is believed that this multifield modulated spintronic THz emitter will provide various possibilities for the integration of next-generation on-chip THz sources and THz modulators.

Purpose: The inverse planning simulated annealing (IPSA) algorithm has shown good results in cancer surgical treatment planning. However, an adaptive approach has not well been proposed for different shapes and sizes of tumors. The purpose of this study was to propose an adaptive, efficient and safe algorithm to get high-quality treatment dose planning, which is presented for pancreatic cancer. Methods: An algorithm employs an optimized IPSA and an adaptive process for adjusting the weight of organs at risk (OAR) and tumor. The algorithm, which was combined with ant colony optimization, was further optimized to reduce the number of needles. It could meet the clinical dose objectives within the tumors, reduce the dose distribution within the OAR and minimize the number of needles. Ten clinical cases were chosen randomly from patients, previously successfully treated in clinic to test our method. The algorithm was validated against clinical cases, using clinically relevant dose parameters. Results: The results were compared with clinical results in ten cases, indicating that the dose distribution within the tumor meets the clinical dose objectives. The dose received by OAR had been greatly reduced, and the number of needles could be reduced by about 50%. It was a significant improvement over the clinical treatment planning. Conclusions: In this paper, we have devised an algorithm to optimize the treatment planning in brachytherapy. The method in this paper could meet the clinical dose objectives and reduce the difficulty of operation. The results were clinically acceptable. This algorithm is also applicable to other cancers such as lung cancer.

The intercalation of transition metal atoms into the van der Waals gap of the layered transition metal dichalcogenides (TMDCs) results in modulations of electronic structures and transport properties of the host materials. In order to reveal the physical mechanism of intercalation, it is essential to elucidate the band structures, especially near the Fermi level, which contributes significantly to physical properties of a solid. Taking advantage of angle-resolved photoemission spectroscopy (ARPES), we studied how Cr intercalation modifies the electronic structures of the pristine ZrTe2in the intercalated compound Cr0.4ZrTe2. By comparing with the semimetal band structures of ZrTe2, we found a nonrigid shift in the band dispersions of Cr0.4ZrTe2, in which an indirect gap opens between the valence and conduction bands with only electron-type carriers contributing to the electronic states at the Fermi level. Moreover, additional electronic states emerge below the bottom of the conduction band at M and exhibit a strong temperature-dependent behavior. Our studies show that the intercalation of atoms in van der Waals crystals could regulate the inherent band dispersions of the host materials and induce new physical properties.

A rechargeable aqueous zinc-ion battery (ZIB) is one of the attractive candidates for large-scale energy storage. Its further application relies on the exploitation of a high-capacity cathode and the understanding of an intrinsic energy storage mechanism. Herein, we report a novel layered K2V3O8cathode material for the ZIB, adopting a strategy of charging first to extract part of K-ions from vanadate in initial few cycles, which creates more electrochemically active sites and lowers charge-transfer resistance of the ZIB system. As a result, a considerable specific capacity of 302.8 mA h g–1at 0.1 A g–1, as well as a remarkable cycling stability (92.3% capacity retention at 4 A g–1for 2000 cycles) and good rate capability, are achieved. Besides, the energy storage mechanism was studied by in situ X-ray diffraction, in situ Raman spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma mass spectroscopy. An irreversible K-ion deintercalation in the first charge process is proved. It is believed that this novel cathode material for the rechargeable aqueous ZIB and the optimizing strategy will shed light on developing next-generation large-scale energy storage devices.

Purpose: Pulmonary nodule detection has great significance for early treating lung cancer and increasing patient survival. This work presents a novel automated computer-aided detection scheme for pulmonary nodules based on deep convolutional neural networks (DCNNs). Methods: The proposed approach employs 3D DCNNs based on squeeze-and-excitation network and residual network (SE-ResNet) for pulmonary nodule candidate detection and false-positive reduction. Specifically, a 3D region proposal network with a U-Net-like structure is designed for detecting pulmonary nodule candidates. For the subsequent false-positive reduction, a 3D SE-ResNet-based classifier is presented to accurately discriminate the true nodules from candidates. The 3D SE-ResNet modules boost the representational power of the network by adaptively recalibrating channel-wise residual feature responses. Both models utilize 3D SE-ResNet modules to learn nodule features effectively and improve nodule detection performance. Results: On the public available lung nodule analysis 2016 dataset with 888 scans included, the proposed method reaches high detection sensitivities of 93.6% and 95.7% at one and four false positives per scan, respectively. Meanwhile, the competition performance metric score of 0.904 is achieved. The proposed method has the capability to detect multi-size nodules, especially the extremely small nodules. Conclusion: In this paper, a 3D DCNNs framework based on 3D SE-ResNet modules is proposed to detect pulmonary nodules in chest CT images accurately. Experimental results demonstrate superior effectiveness of the proposed approach in pulmonary nodule detection task.

Calcium-ion batteries (CIBs) by their strong competitiveness in cost and capacities have been considered as a desirable electrochemical energy technology. Nonetheless, the large ion radius and high charge density of Ca2+lead to sluggish electrochemical reaction kinetics and structural collapse of electrode materials. Herein, we construct a superlattice-like poly 3,4-ethylenedioxythiophene−V2O5(P–V2O5) heterostructure using an in situself-assembly strategy and employ it as a CIB cathode. In the heterostructure, the inserted poly 3,4-ethylenedioxythiophene enlarges the interlayer of V2O5, exposing abundant active sites for efficient Ca2+absorption and transport; meanwhile, it serves as an ‘interlayer linker’ between neighboring layers, which alleviates the volume change of V2O5during Ca2+insertion/extraction processes. Under the synergistic effect of these factors, the P–V2O5electrode exhibits a longer life span and greater rate capability than pristine V2O5. Specifically, the electrode delivers a significant capacity of 157.2 mAh/g at 1 A/g and excellent cycle stability over a long period of 7000 cycles at a high current density of 20 A/g. Furthermore, it has a superior rate capability of 129.0 mAh/g even at 30 A/g. Electrochemical mechanism studies reveal that the insertion/extraction of Ca2+in P–V2O5is highly reversible, accompanied by the interlayer contraction/expansion.

The strong interaction between Ti3C2Sxand FeN4species induces the central metal Fe(II) in FeN4species with intermediate spin state transferred to high spin state, in which the latter is favorable to initiate the reduction of oxygen.This strong interaction induces a remarkable Fe 3delectron delocalization with dband center upshift, boosting oxygen-containing groups adsorption on FeN4species and oxygen reduction reaction kinetics.The resulting FeN4–Ti3C2Sxwith FeN4moieties in high spin state exhibits high half-wave potential of 0.89 V vs. RHE and high limiting current density of 6.5 mA cm−2, enabling wearable zinc–air battery showing a good discharge performance with a maximum power density of 133.6 mW cm−2.

The aqueous zinc ion batteries (ZIBs) composed of inexpensive zinc anode and nontoxic aqueous electrolyte are attractive candidates for large-scale energy storage applications. However, their development is limited by cathode materials, which often deliver inferior rate capability and restricted cycle life. Herein, the VO2nanorods show significant electrochemical performance when used as an intercalation cathode for aqueous ZIBs. Specifically, the VO2nanorods display high initial capacity of 325.6 mAh g–1at 0.05 A g–1, good rate capability, and excellent cycling stability of 5000 cycles at 3.0 A g–1. Furthermore, the VO2unit cell expands in a, b, and cdirections sequentially during the discharge process and contracts back reversibly during the charge process, and the zinc storage mechanism is revealed to be a highly reversible single-phase reaction by operando techniques and corresponding qualitative analyses. Our work not only opens a new door to the practical application of VO2in ZIB systems but also broadens the horizon in understanding the electrochemical behavior of rechargeable ZIBs.

The use of electric-field to manipulate the transport properties of correlated oxides is promising for achieving nano-functional electronic devices. As a typical correlated oxide material, vanadium dioxide (VO2) displays a special metal-insulator transition (MIT) at about 340 K. In this work, we select a water-free electrolyte gel, Li+/propylene carbonate, to achieve a non-volatile and reversible Li-doping and phase modulation in nano-VO2crystal film under gating voltages. Synchrotron characterizations indicate the originally insulating VO2undergoes an effective structure change and an increased V 3d-O 2phybrid t2g-orbital occupancy, which is responsible for the metallic state formation as proved by first-principle calculation. The field-driving Li-doping shows pronounced facet dependence, indicating the existence of energetically favored channels for Li-ions diffusion along V-V chains as proved by dynamic stimulation. Our current findings will supply opportunities for the electric-field control of atomic sieve, correlated ionitronics and synaptic transistor.

Compared with most cathodes for lithium-ion batteries (LIBs), α-MoO3exhibits high specific capacity and therefore receives widespread attention. However, due to its irreversible structural transformation, the capacity of α-MoO3declines rapidly upon discharge-charge process. Herein, via H2plasma etching, oxygen-deficient α-MoO3-xwith improved electrochemical performance is prepared on the basis of pristine α-MoO3(MoO3(I)). The obtained MoO3(II) (10 min etching) and MoO3(III) (20 min etching) have reduced bandgap and expanded van der Waals gap (vdW gap). Electrochemical test results demonstrate MoO3(II) obtains the largest Li+diffusion coefficient, the lowest charge transfer resistance and the slightest polarization. In situ X-ray diffraction characterization further reveals that during cycling, vdW gap of MoO3(II) changes periodically within a small range, indicating a stabilized crystal structure. This work shows that moderate oxygen vacancies can enhance the capacity and stabilize the structure of molybdenum trioxide cathode for LIBs, which has great potential in other cathode materials.

It is of great significance to discover new negative electrode materials featuring a low operating voltage, high capacity and improved initial coulombic efficiency for lithium ion batteries. This is the first report on the use of orthorhombic Li3V(MoO4)3as a promising anode material that exhibits natural advantages over reported traditional metal oxides. High-crystalline Li3V(MoO4)3nanoparticles decorated with carbon are synthesized by a facile mechanochemical route followed by low-temperature (480°C) calcination. The lithium storage ability of the prepared Li3V(MoO4)3anode is fully tapped at 3.0–0.01V vs. Li+/Li, displaying a lower voltage plateau than the conversion-type metal oxides. It delivers a high reversible specific capacity of 999 mAh g−1at 50mAg−1and a high coulombic efficiency of 82.6%. Moreover, it maintains a capacity retention of 92% after 75 cycles at 500mAg−1. The GITT-determined Li+diffusion coefficient ranges from 10−10to 10–13cm2s−1along with the voltage. The lithium storage mechanism indicates that Li3V(MoO4)3can be considered a pre-lithiated material. In-situ XRD testing during the first cycle reflects the conversion reaction of Li3V(MoO4)3. These insights will benefit the discovery of novel anode materials for lithium-ion batteries.

Postimplant validation is an indispensable part in the brachytherapy technique. It provides the necessary feedback to ensure the quality of operation. The ability to pick implanted seed relates directly to the accuracy of validation. To address it, an automatic approach is proposed for picking implanted brachytherapy seeds in 3D CT images. In order to pick seed configuration (location and orientation) efficiently, the approach starts with the segmentation of seed from CT images using a thresholding filter which based on gray-level histogram. Through the process of filtering and denoising, the touching seed and single seed are classified. The true novelty of this approach is found in the application of the canny edge detection and improved concave points matching algorithm to separate touching seeds. Through the computation of image moments, the seed configuration can be determined efficiently. Finally, two different experiments are designed to verify the performance of the proposed approach: (1) physical phantom with 60 model seeds, and (2) patient data with 16 cases. Through assessment of validated results by a medical physicist, the proposed method exhibited promising results. Experiment on phantom demonstrates that the error of seed location and orientation is within ($$0.6\, \pm \, 0.38$$ 0.6±0.38 ) mm and ($$2.4 \pm 1.2$$ 2.4±1.2 )$${^{\circ }}$$ ∘ , respectively. In addition, the most seed location and orientation error is controlled within 0.8 mm and 3.5$${^{\circ }}$$ ∘ in all cases, respectively. The average process time of seed picking is 8.7 s per 100 seeds. In this paper, an automatic, efficient and robust approach, performed on CT images, is proposed to determine the implanted seed location as well as orientation in a 3D workspace. Through the experiments with phantom and patient data, this approach also successfully exhibits good performance.

The aim of this paper is to study the influence of atmospheric humidity and temperature on the mural paintings in the Mogao Grottoes of Dunhuang by measuring the weight of a simulated mural block. Under open conditions, the daily changes in the atmospheric humidity and temperature have an apparent effect on the water content of these murals. There exists an obvious water exchange between atmosphere and mural, that is, there is a ±43 g m−2moisture absorption–desorption ‘breathing’ process between the two. Evapotranspiration from the tree-belt, precipitation, and extremely dry weather also have an effect on the moisture associated with a mural painting. If the cave is closed, a comparable study finds that closure can make the effects of temperature and humidity changes disappear. The mural water content in this case remains stable and the harm due to water-salt deterioration is greatly reduced. Under closed conditions, artificial condensation dehumidification and control of the cave's temperature and humidity stabilizes water activity in the mural paintings very effectively. This is a clear indication of the future steps required to protect the cave's cultural relics.

Li3V2(PO4)3(LVP) was evaluated as a promising cathode material for sodium-ion batteries (SIBs). The three-dimensional graphene frameworks wrapped LVP (LVP-G-FD) exhibited high energy density of 501.3Whkg−1, which is almost the highest energy density among the known polyanionic cathodes for SIBs. The enhanced electrochemical performance of LVP-G-FD is attributed to the graphene framework which provides the fast electronic transport network and buffering space. Besides, the sodium-ion storage mechanism of LVP was investigated via in-situXRD and so on. The sodium-ion storage process is composed of the electrochemical topotactic replacement and the subsequent topotactic reaction.

Extensive use of renewable and clean energy is one of the promising ways to solve energy/environmental problems and promote the sustainable development of our society. As inexhaustible energy sources, the photothermal (PT) and radiative cooling (RC) energy from the sun and outer space have recently attracted tremendous interest. However, these two kinds of energy utilization have distinctly opposite spectral properties, especially in the infrared range, making it extremely difficult to integrate these two energy harvesting modes within a fixed device for continuous energy collection. Thus, in the current study, we have proposed a spectrally self-adaptive broadband absorber/emitter (SSBA/E) based on vanadium dioxide (VO2), a typical phase transition material, to achieve continuous energy harvesting via collecting solar thermal energy in PT mode during the day and obtaining cool energy in wide-band RC mode at night. Experimental results show that owing to the phase transition property of the VO2layer, these two energy collection modes can be adaptively switched. Specifically, the VO2-based device shows a broadband infrared emissivity modulation from 0.21 to 0.75 and low critical temperatures (58.4 and 49.2 °C) during the phase transition, leading to continuous energy harvesting with high efficiency. Due to the broadband infrared emission, the RC maximum power of the SSBA/E device was estimated to be 58 W m–2. The proposed VO2smart coatings are also applicable for many other applications such as thermal management of spacecraft, infrared camouflage, or adaptive optical devices.

Artemisia argyiLévl. et Vant., a perennial Artemisiaherb with an intense fragrance, is widely used in traditional medicine in China and many other Asian countries. Here, we present a chromosome-scale genome assembly of A. argyicomprising 3.89 Gb assembled into 17 pseudochromosomes. Phylogenetic and comparative genomic analyses revealed that A. argyiunderwent a recent lineage-specific whole-genome duplication (WGD) event after divergence from Artemisia annua, resulting in two subgenomes. We deciphered the diploid ancestral genome of A. argyi, and unbiased subgenome evolution was observed. The recent WGD led to a large number of duplicated genes in the A. argyigenome. Expansion of the terpene synthase (TPS) gene family through various types of gene duplication may have greatly contributed to the diversity of volatile terpenoids in A. argyi. In particular, we identified a typical germacrene D synthase gene cluster within the expanded TPS gene family. The entire biosynthetic pathways of germacrenes, (+)-borneol, and (+)-camphor were elucidated in A. argyi. In addition, partial deletion of the amorpha-4,11-diene synthase (ADS) gene and loss of function of ADS homologs may have resulted in the lack of artemisinin production in A. argyi. Our study provides new insights into the genome evolution of Artemisiaand lays a foundation for further improvement of the quality of this important medicinal plant.

NASICON structured NaTi2(PO4)3with stable and open framework has become a promising electrode material for sodium-ion batteries. However, the intrinsic low electronic conductivity of NaTi2(PO4)3leads to inferior rate capability and poor active material utilization. Herein, we first report the synthesis of carbon-coated hierarchical NaTi2(PO4)3mesoporous microflowers (NTP/C-F), viaa facile and controllable solvothermal method and subsequent annealing treatment. The unique structural features endow the NTP/C-F with excellent structural stability, enhanced charge transfer kinetics, and suppressed polarization. This architecture exhibits superior sodium storage performance: high initial capacity (125mAhg−1at 1C), outstanding rate capability (95mAhg−1at 100C), and ultra-long cycling stability (capacity retention of 77.3% after 10,000 cycles at 20C). Time-resolved in-situX-ray diffraction study reveals a typical two-phase electrochemical reaction with reversible structure change. This work suggests the integration of hierarchical structure and carbon coating provides a promising approach for boosting the electrochemical performances of battery electrode materials.

Three-dimensional (3D) hierarchical heterostructures have been widely studied for energy storage because of their amazing synergistic effect. However, a detailed characterization how the branched structure affects the backbone structure during electrochemical cycling, and the specific relationship between the backbone and the branched heterogeneous structure (namely synergistic effect) have been rarely revealed. In addition, the controllable synthesis of this system still remains a great challenge. Herein, we developed a one-step gradient hydrothermal method to obtain a series of 3D hierarchical heterogeneous nanostructures, including V2O5/NaV6O15, V2O5/ZnV2O6and V2O5/CoV2O6, through controlling the sequence of nucleation and growth processes of different structural units in the same precursor. On the basis of time-resolved in situX-ray diffraction (XRD) characterizations, we clearly elucidated the synergistic effect between the branched and backbone structure. During the synergistic effect, the branched NaV6O15helps to reduce the potential barrier during lithium-ion insertion/extraction, buffers the impact of crystal-system transformations during the charge/discharge process; the backbone V2O5is beneficial to increase the charge/discharge capacity, inhibits the self-aggregation of branched NaV6O15and maintains the stability of 3D structure. Consequently, 3D V2O5/NaV6O15hierarchical heterogeneous microspheres exhibit the best electrochemical performance than pure V2O5and V2O5/NaV6O15physical mixture in lithium-ion batteries (LIBs). When tested at a high rate of 5Ag−1, 92% of the initial capacity can be maintained after 1000 cycles. We believe this method will be in favor of the construction of 3D hierarchical heterostructures and this specific synergistic effect investigated by in situXRD will be significant for the design of better electrodes.

We present a controllable synthesis of ternary hierarchical hollow sphere, assembling by numerous particle-like Cu2MoS4, via a facile hydrothermal method. By adding graphene oxides (GO) in the reaction process, Cu2MoS4/reduced graphene oxide (RGO) heterostructures were obtained with enhanced photocurrent and photocatalytic performance. As demonstrated by electron microscopy observations and X-ray characterizations, considerable interfacial contact was achieved between hierarchical Cu2MoS4hollow sphere and RGO, which could facilitate the separation of photoinduced electrons and holes within the hybrid structure. In comparison with the pure Cu2MoS4hollow sphere, the obtained hybrid structures exhibited significantly enhanced light absorption property and the ability of suppressing the photoinduced electron–holes recombination, which led to significant enhancement in both photocurrent and efficiency of photocatalytic methyl orange (MO) degradation under visible light (λ > 420 nm) irradiation.

Na+superionic conductor (NASICON) type Fe2(MoO4)3with capacious ion diffusion tunnels and a flat discharge plateau, is a promising cathode material for sodium ion batteries. However, the sluggish electrochemical kinetics limits its further development due to the poor electron conductivity and long Na+diffusion path. In this work, a graphene wrapped Fe2(MoO4)3nanoparticle composite was synthesized viaa micro-emulsion method followed by annealing. The composite exhibits ultra-high rate capability (64.1mAhg−1at 100C, better than all the reported works) and good high-rate cycling stability (76% capacity retention after 100 cycles at 10C). The enhanced electrochemical performances are attributed to the unique composite structure with shortened ion diffusion distance and high electron conductivity. Furthermore, the Na+insertion/extraction mechanism of the composite is systematically investigated, based on in-situX-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Our work demonstrates that the graphene wrapped Fe2(MoO4)3nanoparticle composite has great potential for high-rate sodium ion batteries.

LiFePO4is one of the most outstanding cathodes for the high performance lithium-ion battery, while it is restricted by its unsatisfactory low temperature performance. Here we detect the structural dynamics and reaction routes of LiFePO4via operando condition with high rates, well reproducibility over cycles and low temperature in common laboratory X-ray without the synchrotron light source. The intermediate phases between LiFePO4and FePO4, driven by the overpotential and limited ion transfer rate along the bdirection at low temperature, are captured. Our results demonstrate that the existence of intermediate can greatly improve the diffusion kinetics of LiFePO4. The deep understanding of reaction routes of LiFePO4at low temperature will guide the further material optimization design. Besides LiFePO4, such high time resolution in-situX-ray diffraction testing method with laboratory source is available to understand the reaction mechanisms of other electrochemical reaction system.

The Dunhuang Mogao Grottoes in China was designated as a world heritage site by UNESCO in 1987 and is famous for its cultural relics. Water is the most active factor that harms the relics in the caves as it damages the grotto murals and painted sculptures. Thus, determining the water sources and driving forces of water movement is a key issue for protecting these cultural relics. These issues have troubled relics protectors for a long time. In this study, the authors chose a representative cave in the Mogao Grottoes and, by completely sealing the cave to make a closed system, measured the water vapor from the surrounding rock. This was accomplished by installing a condensation-dehumidification temperature-humidity control system for the collection of water vapor. The results show that there is continuous evaporation from the deep surrounding rock into the cave. The daily evaporation capacity is determined to be 1.02 g/(d·m2). The water sources and driving forces of water movement were further analyzed according to the character of the water evaporation and by monitoring the temperature and humidity of the surrounding rock. It was found that the water vapor in the cave derives from phreatic water. Moreover, the yearly fluctuation of temperature in the surrounding rock and geothermal forces are the basic powers responsible for driving phreatic evaporation. Under the action of the yearly temperature fluctuations, decomposition and combination of bound water acts as a “pump” that drives phreatic water migration and evaporation. When the temperature rises, bound water decomposes and evaporates; and when it falls, the rock absorbs moisture. This causes the phreatic water to move from deep regions to shallow ones. Determining the source and dynamic foundation of the water provides a firm scientific basis for protecting the valuable cultural relics in the caves.

The BaCaBO3F wide band gap host and the charge-compensated phosphors BaCaBO3F:Ln3+(Ln = Ce, Tb, Gd) and BaCaBO3F:Ce3+,Tb3+have been synthesized by a solid-state reaction method at high temperature. Their spectroscopic properties in the vacuum ultraviolet (VUV)–vis range have been investigated. The band gap of the host lattice is estimated at 7.8 eV, which is considerably higher than the value found from its diffuse reflectance spectrum. The 5d crystal field level locations, Stokes shift, and Huang–Rhys factor have been determined from the VUV excitation and near-UV emission spectra of BaCaBO3F:Ce3+. The 5d1decay lifetime is 29 ns at x∼ 0.005. Concentration quenching occurs for Ba1–2xCexNaxCaBO3F with maximum intensity at x∼ 0.035 and with critical distance Rc= 17.7 Å. An unusual broad, intense band in the excitation spectrum of BaCaBO3F:Gd3+is assigned to a near-defect exciton. Very weak emission from 5D3, and intense green emission from 5D4, has been assigned for BaCaBO3F:Tb3+. In the VUV region, the spin-allowed and the spin-forbidden 4f8→ 4f75d transitions are observed. The codoped system BaCaBO3F:Ce3+,Tb3+exhibits emission color tunability when varying the excitation wavelength or the dopant ion concentration. The energy transfer from Ce3+to Tb3+takes place in the fast migration regime with kET∼ 106–107s–1and with energy-transfer efficiency up to 23% for the samples investigated. The mechanism is revealed from energy level and decay measurements. This codoped system exhibits absorption bands near the major Xe discharge wavelengths.

The work presents the VUV-UV–vis photoluminescence of Ba3La(PO4)3:Ln3+(Ln = Tb, Eu) prepared by a high-temperature solid-state reaction route. The excitation and emission spectra, the fluorescence decays, and the time-resolved emission spectra were measured and discussed in detail. The results reveal that Tb3+can efficiently transfer excitation energy to Eu3+via its 5d and 4f states and therefore sensitizes Eu3+emission under VUV-UV excitation, resulting in tunable emission in a large color gamut.

To improve the energy conversion of solar irradiation, a photocatalyst with high reactivity under visible light is required. Using density functional theory, the structural and electronic properties of iodine cation-doped rutile TiO2are studied. The total energy calculations show that iodine substituting for titanium sites in TiO2matrix is energetically favorable. The electronic structure calculations reveal that iodine doping induces a delocalized band consisting of I 5s states and O 2p states at the top of the valence band of TiO2. Due to this delocalized state, the band gap is markedly narrowed by about 0.4 eV, the optical absorption is extended to the visible light region, and the excited electron−hole pairs are expected to have better mobility. Moreover, the conduction band edge is raised above the reduction level of H2/H2O by I-doping, which enables the achievement of high photocatalytic efficiency of I-doped rutile TiO2.

The orthophosphate phosphors, Ba_3La(PO_4)_3 activated with Dy^3+ and Gd^3+-Dy^3+ ions, were prepared by a solid reaction technique at high temperature. Their spectroscopic properties were investigated in the vacuum ultraviolet (VUV)-visible range. We found that the introducing of Gd^3+ greatly enhances the Dy^3+ luminescence under 172 nm VUV excitation. The measurements on excitation spectra, emission spectra, and luminescence decay curves revealed that the energy transfer between Gd^3+ and Dy^3+ becomes more and more efficient with the increasing Gd^3+ contents.

A series of samples with nominal chemical formulas La 2− xCe xCaB 10O 19and La 2Ca 1−2 xCe xNa xB 10O 19were prepared by a solid state reaction route at high temperature. Their luminescence properties were investigated by the steady state excitation and emission spectra in the VUV−vis range, the luminescence decays, and the time-resolved emission spectra (TRES). The results demonstrate that Ce 3+ions occupy two lattice sites in all samples. The lowest 5d absorption bands for two sites are at about 272 (La 3+site) and 312 nm (Ca 2+site), respectively. The emission for Ce 3+in the La 3+site shows a shorter decay time of 12 ns, and the doublet emission bands have maxima at about 291 and 310 nm. The emission for the Ce 3+in Ca 2+site has a longer lifetime of 26 ns with band maxima at about 329 and 355 nm. Efficient energy transfer between both sites occurs in the samples.