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Ultrathin (5–50 nm) epitaxial superconducting niobium nitride (NbN) films were grown on AlN-buffered c-plane Al2O3 by an industrial scale physical vapor deposition technique at 400°C. Both X-ray diffraction and scanning electron microscopy analysis show high crystallinity of the (111)-oriented NbN films, with a narrow full-width-at-half-maximum of the rocking curve down to 0.030°. The lattice constant decreases with decreasing NbN layer thickness, suggesting lattice strain for films with thicknesses below 20 nm. The superconducting transition temperature, the transition width, the upper critical field, the irreversibility line, and the coherence length are closely correlated to the film thickness. This work realized high quality ultrathin epitaxial NbN films by an industry-scale PVD technology at low substrate temperature, which opens up new opportunities for quantum devices.

The seeds of Cercis chinensis Bunge are important for reproduction and propagation, but strong dormancy controls their germination. To elucidate the causes of seed dormancy in C. chinensis, we investigated the permeability of the hard seed coat and the contribution of the endosperm to physical dormancy, and we examined the effect of extracts from the seed coat and endosperm. In addition, the effectiveness of scarification methods to break seed dormancy was compared. Cercis chinensis seeds exhibited physical and physiological dormancy. The hard seed coat played an important role in limiting water uptake, and the endosperm acted as a physical barrier that restricted embryo development in imbibed seeds. Germination percentage of Chinese cabbage [Brassica rapa subsp. chinensis (L.) Hanelt] seeds was reduced from 98% (control) to 28.3% and 56.7% with a seed-coat extract and an endosperm extract, respectively. This demonstrated that both the seed coat and endosperm contained endogenous inhibitors, but the seed-coat extract resulted in stronger inhibition. Mechanical scarification, thermal scarification, and chemical scarification had positive effects on C. chinensis seed germination. Soaking non-scarified seeds in gibberellic acid (GA3) solution did not promote germination; however, treatment with exogenous GA3 following scarification significantly improved germination. The optimal method for promoting C. chinensis seed germination was soaking scarified seeds in 500 mg·L−1 GA3 for 24 h followed by cold stratification at 5 °C for 2 mo.

Previous studies have shown that Bi segregation at the Cu3Sn/Cu interface in eutectic 42Sn-58Bi/Cu interconnects induces brittle fracture along this interface after aging at 120°C for 7 days. To verify whether Bi can still be applied in lead-free solder alloys, compact tension tests were conducted on Sn-10Bi-0.7Cu/Cu joints in as-reflowed and aged (at 180°C for 17 days) conditions, and their interfacial structure was studied by scanning electron microscopy (SEM). After aging the joints at 180°C for 17 days, the average thickness of intermetallic compound (IMC) between the solder and Cu substrate in the interconnect increased from 4 ± 1 μm to 25 ± 1 μm, the average fracture toughness dropped from 0.777 ± 0.002 MPa m1/2 to 0.297 ± 0.001 MPa m1/2, while the interconnects did not fracture in fragile fashion along the Cu3Sn/Cu interface. No Bi segregation was found at the Cu3Sn/Cu interface in the Sn-10Bi-0.7Cu/Cu interconnect aged at 180°C for 17 days, while Bi particles were found at the counterpart interface in the eutectic 42Sn-58Bi/Cu joint aged at 180°C for 2 days. Cu3Sn formed by consumption of Cu6Sn5 during IMC growth in the interconnect. The Bi segregation was caused because the content of Bi dissolved in Cu6Sn5 was higher than the maximum solubility of Cu3Sn in the eutectic 42Sn-58Bi/Cu interconnect. Bi precipitation and segregation occurred when the Cu6Sn5 IMC turned into Cu3Sn IMC. Electron probe microanalysis revealed that the amount of Bi dissolved in the Cu6Sn5 IMC in the solder joint depended on the Bi content in the solder alloy. The test results revealed that lead-free solder alloys with Bi content less than 10 wt.% will not lead to Bi segregation, which would greatly degrade the solder/Cu joint.

Recycling of waste electrical and electronic equipment has become an urgent global issue in recent years from the prospectives of resources recycling and environmental protection. In the present work, the recycling of waste memory modules (WMMs) through low-temperature alkali melts was investigated, based on the thermodynamic analysis of the nonmetallic reactions of brominated epoxy resin, glass fiber and memory chip with the molten mixed alkali. The effects of the reaction temperature and the ratio of alkali mixture on the removal rate of nonmetallic parts in WMMs were discussed under the condition of air atmosphere. The optimum process parameters were further confirmed by in-situ monitoring of the temperature during the whole reaction process. The mixtures with Cu, Fe and Ni as the main components were obtained after the treatment of WMMs in the molten alkali. These mixed metals were further separated into copper-rich and ferronickel-rich metals by physical magnetic separation. Moreover, the precious metals Au and Ag were enriched in Cu-rich alloys. This work provided an efficient and environment-friendly method for metal recycling from WMMs.

(1-x)(Pb0.97La0.02)(Zr0.5Sn0.4Ti0.1)O3-x(Na0.5Bi0.5)0.94Ba0.06TiO3 (x = 0 ∼ 0.4) ceramics have been prepared and investigated. The ceramics consist of perovskite solid solution matrix and precipitated, isolated SnO2 particle, resulting in 0–3 type composite structure. With increasing x value, the room temperature crystal structure of perovskite solid solution transforms from tetragonal to pseudocubic, therefore, the electrical property evaluates form robust antiferroelectric at x = 0, metastable antiferroelectric at x = 0.1, and then relaxor ferroelectric at x > 0.1. Moreover, the breakdown strength is enhanced due to the composite structure and reaches maximum value of 190 kV/cm at x = 0.2. Both the phase transition and enhanced breakdown strength are helpful to improve energy storage property, the x = 0.2 ceramic shows largest recoverable energy density wrec of 1.84 J/cm3, discharge efficiency η of 86.6 %. Especially, both wrec and η illustrates significantly improved thermal stability within 25−125 °C.

Nowadays, energy and the environment have become critical issues for determining the sustainability of the Earth. Freshwater crises, as an increasingly serious global problem, pose a great threat to our economies, the environment and us. Solar-driven evaporation has emerged as a promising and sustainable approach to convert solar energy into clean water. In fact, the production of freshwater is not only governed by heat generation at the interface, but the process also relies on the coordination and cooperation of functional modules in the solar-driven evaporation system. This review begins with system designs of solar evaporators, considering thermal manipulation structures, water transportation pathways, and vapour condensation modules, which focus on improving the overall energy utilization, long-term usability, and freshwater yield. This is followed by a summary and discussions of cutting-edge solar evaporation applications and their underlying mechanisms. Finally, existing challenges and potential solutions for future applications are discussed and provided. This review aims to provide useful guidelines and references to scientists and researchers for the future development of clean water generation systems.

The research goal of this article is to imaging the oil distribution in landing gear hydraulic cylinder by Positron Emission Tomography(PET). Considering the flexibility and commercial cost for automation testing, two kinds of Not-Full-Ring sensors arrangement, Uniform-arrangement and Bilateral-arrangement, are proposed. The Full-Ring PET is used as the contrast template of imaging. Firstly, GATE 7.1 is used as the Monte Carlo simulation platform to simulate the sensors arrangement of the two Not-Full-Ring schemes. The results of scattering fraction, sensitivity and photon energy distribution were used to evaluate the feasibility of the two schemes. Then, a set of verification device with rotating platform and variable sensing diameter is constructed. The two kinds of Not-Full-Ring sensors arrangements were verified through the verification device. By imaging the hydraulic oil in the hydraulic cylinder, the results were evaluated and compared by using Signal Noise Ratio(SNR). According to the simulation and verification results, Not-Full-Ring scheme is feasible for imaging the liquid distribution in the hydraulic cavity. Uniform- arrangement has a more better imaging performance than Bilateral-arrangement. Such sensors arrangement scheme is not only suitable for this research, but also suitable for other PET imaging applications which need to consider the flexibility and commercial cost.

Unquenched and quenched ceramics of 0.85Na0.5Bi0.5TiO3-0.11K0.5Bi0.5TiO3-0.04BaTiO3 have been prepared, and their crystal structure, temperature-dependent ferro-/piezoelectric properties and domain structure have been comparatively investigated. It is shown that quenching process can significantly improve the ferroelectric-relaxor transition temperature (TF-R), which is 130 °C for unquenched ceramics and 198 °C for quenched one. As the result, the thermal stability of ferro-/piezoelectric properties is highly enhanced. These observations are mainly attributed to the quenching induced stable rhombohedral ferroelectric phase and the defect altered domain evolution. This work may deepen the understanding of the effect of quenching on crystal structure, domain structure and their contributions to thermal stability of NBT-based ceramics.

The high-resolution transmission (HITRAN) database has been updated recently. Therefore, it is useful to analyze the effect of the updated data on radiative transfer calculations. This study identifies the impact of database updates that could affect climate models and satellite remote sensing applications. The fluxes and cooling rates of the longwave region are calculated by the line-by-line radiative transfer model based on the HITRAN08, HITRAN12 and HITRAN16 molecule spectroscopic databases under four typical atmospheric profiles. We show that the differences in cooling rates are mainly caused by the changes in the line parameters of H2O and CO2. The maximum difference in the upward fluxes at the top of the atmosphere between HITRAN08 and HITRAN16 is 0.6587 W m−2, whereas that between HITRAN12 and HITRAN16 is only 0.0406 W m−2, which is much smaller than the maximum difference between HITRAN08 and HITRAN16. Similar trends are also observed in the downward fluxes at the surface and cooling rates. Overall these differences are all less than the typical errors of radiative transfer schemes. On the contrary, we show that there are differences between the simulated brightness temperatures for the channels of hyperspectral measurements, such as FY-3D Hyperspectral Infrared Atmospheric Sounder (HIRAS), which are at least comparable to the noise equivalent temperature difference (NETD) of the corresponding channels. Therefore, it is necessary to consider the effect of using different HITRAN molecular spectroscopic databases in hyperspectral satellite remote sensing applications.

We prepared Au-LaNiO3−δ (Au-LNO) nanocomposite thin films by a sol–gel coating method. The effects of the doped Au on the microstructure and electrical properties of the Au-LNO films under different types of thermal strain were investigated. Introduction of Au into the LNO films changed their preferential orientation and markedly lowered their room-temperature resistivity. Moreover, the resistivity of the films containing Au nanoparticles showed negligible dependence on thermal strain, in contrast to the behavior of Au-free LNO films. We performed microstrain analysis and x-ray photoelectron spectroscopy to explore the strain–resistivity relationship of the films. Microstrain was closely related to the density of oxygen vacancies in LNO films and dominated the change in electrical properties of polycrystalline LNO films. The addition of Au promoted crystallization of the LNO films and decreased the density of oxygen vacancies, which stabilized the microstrain in the films under different external strain and accounted for the strain independence of the resistivity of the Au-LNO films.

Background Water uptake is essential for seed germination. However, Gleditsia sinensis seeds have a water-impermeable seed coat, which is beneficial for its adaption to the environment, but prohibits its germination without treatment. This feature may be associated with the structure of the seed coat. Thus, the aim of this research was to identify and describe the initial water uptake site and water movement and to determine the relationship between seed coat structure and water absorption. Results A water temperature of 80 °C was optimal to break the hardseededness of G. sinensis seeds. Scanning electron microscopy (SEM) images revealed that the seed coat consisted of a palisade layer and light line that can hinder water entry into the seed. Also, a structure of vascular bundles existed in the hilar region. Hot water treatment caused the tightly closed micropyle to open and the cavity beneath it expanded; the layer of palisade cells in the lens was raised. The embryo dye-tracking tests showed that the radicle tip was the initial region to be stained red. After staining for 24 h, the red-stained area on the vascular bundle side of cotyledon was more extensive than that on the other side. Further studies by MRI maps indicated that the micropyle was the initial site for water imbibition. Some water then migrated along the space between the seed coat and the endosperm to the chalazal; simultaneously, the rest of the water reached the embryonic axis and spread into cotyledons. The maps of 20–24 h showed that water was unevenly distributed within the cotyledons in a way that the edge parts were more hydrated than the center. Blocking tests showed that the hilar region was the initial and an important region during seed imbibition. The medial region and chalazal portion were capable of imbibing water when the hilar region was blocked, but water absorption was later and slower than that through the hilar region. Conclusion MRI technology provides a promising and non-invasive technique to identify the water gap and the path of water movement in the seed. Combined with the results of SEM, the relation between seed coat and its imbibition can be inferred.

Hereditary multiple exostoses (HME) is a rare skeletal disorder characterized by the formation of multiple benign cartilage-capped tumors, usually in the metaphyseal region of the long bones. Over 70% of HME cases arise from monoallelic mutations in either of the two genes encoding the heparan sulfate (HS) synthesis enzymes, ext1 and ext2. To identify more HME-associated mutations, genomic DNA from members of five independent consanguineous families with HME was sequenced with whole exome sequencing (WES). A novel heterozygous splice site mutation (c.1173+2T>A) in ext2 was detected in all three affected members of family V. Further study showed that the novel mutation caused exon 7 of ext2 mRNA to be skipped during splicing and caused a frameshift after the codon for Arg360, which results in the appearance of new 43 codons, followed by a termination codon. Although the resulting truncated protein was still localized to the Golgi, similar to the full-length EXT2, its HS synthesis activity decreased by 40%. In this study, a novel splice site mutation in ext2 was identified and suggested to be a pathogenic mutation of HME, which may expand the genetic etiology spectrum of HME and may be helpful for clinical genetic counseling and prenatal diagnosis.

An efficient radiative transfer model (ERTM) is developed to simulate thermal infrared brightness temperatures observed by the Advanced Himawari Imager (AHI) in this study. The ERTM contains an alternate mapping correlated k-distribution (AMCKD) scheme, a parameterization for cloud optical property, and a rapid infrared radiative transfer scheme. The AMCKD is employed to calculate the gaseous absorption in the inhomogeneous thermodynamic atmosphere. The optical properties of clouds are parameterized by the effective length for ice clouds based on the Voronoi model, and by the effective radius for water clouds based on the Lorenz-Mie theory. The adding method of four-stream discrete ordinates method (4DDA) is extended to be able to calculate the thermal infrared radiative intensity varying with the zenith angle in ERTM. The efficiency and accuracy of ERTM are evaluated by comparing with the benchmark model which is composed of discrete ordinate radiative transfer (DISORT) and line-by-line radiative transfer model (LBLRTM). Under the standard atmospheric profiles, the root mean square error (RMSE) of simulated brightness temperatures reaches a maximum of 0.21K at the B16 (13.28 µm) channel of AHI. The computational efficiency of ERTM is approximately five orders of magnitude higher than that of the benchmark model. Moreover, the simulated brightness temperatures by ERTM are highly consistent with the rigorous results and AHI observations in the application to the Typhoon Mujigae case.

This study identifies endogenous inhibitors of germination associated with seed dormancy in Sapium sebiferum, Chinese tallow. Seed extracts were separated into five distinct fractions (petroleum ether, ether, ethyl acetate, methanol, and aqueous) and tested for their effect on germination of cabbage seeds. There were no significant differences in germination percentages and germination index (GI) between the solvents and the control. The five fractions differentially reduced germination percentage and GI values of cabbage seeds. According to the GI results, the greatest inhibition was with the ether fraction followed by methanol, ethyl acetate, petroleum ether, and aqueous fractions. Gas chromatography–mass spectrometry identified the constituents of the four organic fractions. Compared with the mass spectrum of the National Institute of Standards and Technology library, a compound was confirmed, provided it was more than 85% similar. Analysis of ether extracts identified four compounds: butylated hydroxytoluene (BHT; 19.7%), 1,2-benzenediol (4.1%), p-hydroxycinnamic acid, ethyl ester (2.8%), and n-hexadecanoic acid (1.4%). Fourteen, 20, and 9 compounds were identified in methanol, ethyl acetate, and petroleum ether extracts, respectively. The IC50 of BHT (the concentration at which BHT inhibits radicle growth by 50%) was 54.8 mg/L, indicating that the presence of BHT might be the primary cause of dormancy in S. sebiferum seeds.

The mechanical parameters of viscoelastic materials, such as storage modulus and loss factor, have frequency-dependent characteristic and the combination of different polymers usually exhibits various mechanical characteristics, which make the identification of the mechanical parameters of viscoelastic materials become a routine and challenging task. In this study, based on the measured resonance frequencies and frequency response functions (FRFs) of a viscoelastic damping plate, an inverse approach was developed to identify the aforementioned parameters with frequency-dependent characteristic. An analysis model was established with both the viscoelastic material damping and the remaining equivalent viscous damping considered. A response surface method was provided to achieve the matching calculation, which can identify the storage modulus and loss factor simultaneously. A cantilever plate attached with ZN_1 viscoelastic material was chosen to demonstrate the proposed method and the measured and the predicted FRFs were compared with the purpose of assessing the rationality of identification results. The results show that the loss factor of viscoelastic materials would be overestimated if only the material damping was included in the analysis model.

Several schemes have been proposed for handling gaseous overlapping bands in the context of the correlated k-distribution model (CKD), but they all require manual operation and the accuracy is limited. In this paper, we proposed two automatic methods for gas absorption calculation based on correlated k-distribution, namely finding point method (FPM) and re-optimized method (ROM), to improve the accuracy and the speed of gaseous absorption calculation. Compared with the line-by-line (LBL) results under standard profiles, the resulting accuracy of FPM is 0.09 Kday−1 in troposphere, -0.3 Kday−1 in stratosphere, -0.18 W/m2 for upward flux and -0.44 W/m2 for downward flux; the accuracy of ROM is 0.1 Kday−1 in troposphere, 0.3 Kday−1 in stratosphere, -0.35 W/m2 for upward flux and -0.18 W/m2 for downward flux. The accuracy of the two methods is higher than rapid radiative transfer model for general circulation models (RRTMG). Under realistic profiles, the accuracy of FPM and ROM is slightly lower than that their accuracy under standard profiles but still higher than RRTMG.

We numerically investigate the coupling effects of surface plasmon polaritons (SPPs) and magnetic dipole (MD) resonances in metamaterials, which are composed of an Ag nanodisk array and a SiO2 spacer on an Ag substrate. The periodicity of the Ag nanodisk array leads to the excitation of SPPs at the surface of the Ag substrate. The near-field plasmon interactions between individual Ag nanodisks and the Ag substrate form MD resonances. When the excitation wavelengths of SPPs are tuned to approach the position of MD resonances by changing the array period of Ag nanodisks, SPPs and MD resonances are coupled together into two hybridized modes, whose positions can be well predicted by a coupling model of two oscillators. In the strong coupling regime of SPPs and MD resonances, the hybridized modes exhibit an obvious anti-crossing, resulting into an interesting phenomenon of Rabi splitting. Moreover, the magnetic fields under the Ag nanodisks are greatly enhanced, which may find some potential applications, such as magnetic nonlinearity.

Wood, an earth-abundant material, is widely used in our everyday life. With its mesoporous structure, natural wood is comprised of numerous long, partially aligned channels (lumens) as well as nanochannels that stretch along its growth direction. This wood mesostructure is suitable for a range of emerging applications, especially as a membrane/separation material. Here, we report a mesoporous, three-dimensional (3D) wood membrane decorated with palladium nanoparticles (Pd NPs/wood membrane) for efficient wastewater treatment. The 3D Pd NPs/wood membrane possesses the following advantages: (1) the uniformly distributed lignin within the wood mesostructure can effectively reduce Pd(II) ions to Pd NPs; (2) cellulose, with its abundant hydroxyl groups, can immobilize Pd NPs; (3) the partially aligned mesoporous wood channels as well as their inner ingenious microstructures increase the likelihood of wastewater contacting Pd NPs decorating the wood surface; (4) the long, Pd NP-decorated channels facilitate bulk treatment as water flows through the entire mesoporous wood membrane. As a proof of concept, we demonstrated the use and efficiency of a Pd NPs/wood membrane to remove methylene blue (MB, C

In this article, free vibration of the hard-coating cantilever cylindrical shell is investigated considering the elastic constraints at the clamped end. Love's first approximation theory and Rayleigh–Ritz method are applied to build the analytical model of hard-coating cylindrical shell. In the modeling process, orthogonal polynomials are used as admissible displacement functions to formulate the displacement field, and the elastic constraints are simulated by constrained springs whose stiffness values are determined using model updating technique. The developed model has been validated by the comparison between the natural frequencies obtained by analytical calculation and by experiment respectively. Finally, the influences of hard-coating parameters, including thickness, Young's modulus and loss factor, on the vibration characteristics of the cylindrical shell are studied.

Plasmonic nanostructures are successfully demonstrated in solar cells due to their broad spectra-selective resonance in the range of ultraviolet to near-infrared, and thus light absorption can be mostly improved and power conversion efficiency (PCE) further. Here, we demonstrate plasmonic dye-sensitized solar cells (DSSCs) using collapsible Au nanofingers to build photoanode to enhance light absorption. In this plasmonic DSSCs, by balancing local field enhancement due to gap-plasmon resonance and dye fluorescence quenching, the optimal gap size in collapsed Au/Al2O3/Au nanofingers is designed by twice the Al2O3thickness and then deposited a TiO2layer as photoanode. The results show that the PCE of DSSCs is mostly improved as compared to DSSCs with photoanode of Au/Al2O3/TiO2films, which can be ascribed to the coupled local field enhancement within the sub-nanometer gaps. In addition, fluorescence of dyes on plasmonic nanofingers is nearly 10 times higher than plain Au/Al2O3/TiO2films, which further proves the dye absorption enhancement. These plasmonic nanofingers enable the precise engineering of gap-plasmon modes and can be scaled up to wafer scale with low cost by the nanoimprint lithography technique, which suggests the feasibility of applying our result in constructing the photoanode for other types of solar cells.

High-entropy alloys (HEAs) have been extensively studied in recent years. However, yield strength of HEAs in which austenite is the dominating phase is usually low, far from satisfying the engineering demands. Improving performance-cost ratio of such alloys will help for their practical structural applications. Here we report a novel strategy to produce ultrastrong, tough, and low-cost HEAs, in which heavy nitrogen-doping (2.6 at.%) was applied to an inexpensive metastable FeMnCoCr HEA. Coupled with simple thermomechanical processing, we produced a multi-heterostructure, which consisted of fine α-martensite laths, deformed austenite with dense dislocations, recrystallized ultrafine grains and nano-nitride precipitates. Our novel FeMnCoCrN HEA exhibits a high yield strength of 1310 MPa which is ~5.2 times stronger than its base alloy without nitrogen doping. In particular, the highly dislocated body-centered cubic (bcc) martensite laths formed in the austenitic deformation matrix has an unexpected area fraction up to 24%. The hetero-deformation induced strengthening then reaches 750 MPa at the yield point, leading to a remarkable yield strength elevation of the material. Moreover, the high nitrogen content changes the dominant deformation mechanism from martensitic transformation to twinning, which contributes to a satisfactory uniform elongation of 16.5%, while the material is further strengthened by the dynamically refined microstructure. The high-nitrogen duplex alloy design strategy developed here provides a new paradigm for developing high-performance fcc HEAs.

Highly efficient broadband light management to enhance the light trapping inside active layer is critical for many energy conversion devices such as thin film solar cells and photoelectrochemical cells. In this work, we demonstrate highly transparent, mesoporous wood composite via fast extraction of lignin along naturally formed low tortuosity channels followed by fast filling of polymers. The transparent wood displays a high optical transmittance and at the same time a high haze in a broad wavelength range between 400 nm and 1100 nm. With such unique optical properties, the transparent wood composite with cellulose nanofibers can be utilized for a range of optoelectronics, especially for solar cells and wide-angle lighting where light management is crucial to enhance device operation efficiency. We demonstrate that the newly developed transparent wood composite can function as a broad range light management layer and substantially improve the overall energy conversion efficiency by as much as 18% when simply coated with a GaAs thin film solar cell. Our research on wood based light management material provides an attractive platform for future development embracing green, disposable optoelectronic devices with efficient light management.

For the first time, two types of highly anisotropic, highly transparent wood composites are demonstrated by taking advantage of the macro-structures in original wood. These wood composites are highly transparent with a total transmittance up to 90% but exhibit dramatically different optical and mechanical properties.

Optoelectronic devices are ubiquitously built on substrates. To increase the efficiencies of light coupling into and out of optoelectronic devices, such as thin film solar cells and flexible lighting, a substrate with high transmittance and high haze is desired. Unfortunately, optical transmittance and optical haze are usually contrasting to each other in common substrates: plastic is highly transparent but with a low optical haze, whereas paper has a high optical haze but a low total transmittance. Herein, we combine these two materials through a simple templated infiltration approach to achieve a new type of substrate, plastic–paper, which has a high optical transmittance (>85%) and high transmittance haze (>90%) in a broadband wavelength. The plastic–paper has an ultra-flat surface, is mechanically flexible, durable in different solvents and compatible with standard processing in semiconductors, which are shown by organic light emitting diodes (OLED) fabricated directly onto the plastic–paper substrate. Plastic–paper leads to improved light coupling into and out of optoelectronic devices and demonstrates an improvement in efficiency for both OLED and typical GaAs solar cells. The fabrication method is also fully scalable with roll-to-roll production. The newly developed low-cost, high-performance transparent and hazy substrate is attractive for a range of optoelectronic devices.

Flexible electronics have found useful applications in both the scientific and industrial communities. However, substrates traditionally used for flexible electronics, such as plastic, cause many environmental issues. Therefore, a transparent substrate made from natural materials provides a promising alternative because it can be degraded in nature. The traditional bottom-up fabrication method for transparent paper is expensive, environmentally unfriendly, and time-consuming. In this work, for the first time, we developed a top-down method to fabricate isotropic, transparent paper directly from anisotropic wood. The top-down method includes two steps: a delignification process to bleach the wood by lignin removal and a pressing process for removing light-reflecting and -scattering sources. The resulting isotropic, transparent paper has high transmittance of about 90% and high haze over 80% and is demonstrated as a nature-disposable substrate for electronic/optical devices. Adjusting the pressing ratio used changes the density of the resulting paper, which tunes the microstructure-related properties of the isotropic, transparent paper. This top-down method is simple, fast, environmentally friendly, and cost-effective, which can greatly promote the development of paper-based green optical and electronic devices.

Fano resonance modulated effectively by external perturbations can find more flexible and important applications in practice. We theoretically study electrically tunable Fano resonance with asymmetric line shape over an extremely narrow frequency range in the reflection spectra of metamaterials. The metamaterials are composed of a metal nanodisk array on graphene, a dielectric spacer, and a metal substrate. The near-field plasmon hybridization between individual metal nanodisks and the metal substrate results into the excitation of a broad magnetic dipole. There exists a narrow interband transition dependent of Fermi energy E f , which manifests itself as a sharp spectral feature in the effective permittivity ε g of graphene. The coupling of the narrow interband transition to the broad magnetic dipole leads to the appearance of Fano resonance, which can be electrically tuned by applying a bias voltage to graphene to change E f . The Fano resonance will shift obviously and its asymmetric line shape will become more pronounced, when E f is changed for the narrow interband transition to progressively approach the broad magnetic dipole.

Facing with bilingual news event's attributes association about Chinese and Vietnamese, we propose a bilingual news event sequencing method based on graph of attributes association. This method built the graph of attributes association based on the relations between event properties and it sequences the Chinese and Vietnamese bilingual news event using this graph. This method first extracts the titles, elements, topic sentences which characterize bilingual news event properties. And it uses the extractions to describe events in the document. Then we translate these title, elements and topic sentences by using the bilingual dictionary and Vietnamese-Chinese Alignment Corpora. And we build the graph of attributes association. We calculate the weights of edges by using word2vec and elements co-occurrence strength. In the end, it sequences the bilingual news using similarity among event node, query keyword and connection between the graph's nodes and event. The experimental results show that the proposed method can effectively improve the performance of the ranking of the news events in the Chinese and Vietnamese, and the attribute relevance has a good effect on the ranking of the Chinese and Vietnamese news events.

Synthetic structural materials with exceptional mechanical performance suffer from either large weight and adverse environmental impact (for example, steels and alloys) or complex manufacturing processes and thus high cost (for example, polymer-based and biomimetic composites). Natural wood is a low-cost and abundant material and has been used for millennia as a structural material for building and furniture construction. However, the mechanical performance of natural wood (its strength and toughness) is unsatisfactory for many advanced engineering structures and applications. Pre-treatment with steam, heat, ammonia or cold rolling followed by densification has led to the enhanced mechanical performance of natural wood. However, the existing methods result in incomplete densification and lack dimensional stability, particularly in response to humid environments, and wood treated in these ways can expand and weaken. Here we report a simple and effective strategy to transform bulk natural wood directly into a high-performance structural material with a more than tenfold increase in strength, toughness and ballistic resistance and with greater dimensional stability. Our two-step process involves the partial removal of lignin and hemicellulose from the natural wood via a boiling process in an aqueous mixture of NaOH and Na2SO3 followed by hot-pressing, leading to the total collapse of cell walls and the complete densification of the natural wood with highly aligned cellulose nanofibres. This strategy is shown to be universally effective for various species of wood. Our processed wood has a specific strength higher than that of most structural metals and alloys, making it a low-cost, high-performance, lightweight alternative.

This research has experimentally investigated the influence on vibration characteristics of thin cantilever cylindrical shell (TCS) with hard coating under cantilever boundary condition. Firstly, the theoretical model of TCS with hard coating is established to calculate its natural frequencies and modal shapes so as to roughly understand vibration characteristic of TCS when it is coated with hard coating material. Then, by considering its nonlinear stiffness and damping influences, an experiment system is established to accurately measure vibration parameters of the shell, and the corresponding test methods and identification techniques are also proposed. Finally, based on the measured data, the influences on natural frequencies, modal shapes, damping ratios, and vibration responses of TCS with hard coating are analyzed and discussed in detail. It can be found that hard coating can play an important role in vibration reduction of TCS, and for the most modes of TCS, hard coating will result in the decrease of natural frequencies, but the decreased level is not very big, and its damping effects on the higher frequency range of the shell are weak and ineffective. Therefore, in order to make better use of this coating material, we must carefully choose the concerned antivibration frequency range of the shell; otherwise it may lead to some negative effects.

Wood is a ubiquitous material, widely used in human society, that features naturally abundant, aligned longitudinal cells (e.g., tracheids in softwood and fibers/vessels in hardwood) with diameters of ≈50-1000 µm. Here, the realization of, fine patterns on a wood surface ranging in size from 40 nm to 50 µm by precision imprinting is described. The precision imprinting is enabled by releasing cellulose fibril aggregates from the bondage of lignin through the delignification process, then imprinting in wet condition and fixing the designed configuration in the dry state. Various precision structures on a wood surface using imprinting technology, including dot arrays, lines, triangular features, and other complex patterns, are successfully demonstrated. Even multiscale structures with nanosized lines on the surface of micrometer hemiballs can be acquired. As a proof of concept, the use of surface-imprinted wood as a microlens array (MLA), which exhibits superior imaging ability and thermal stability even at a high temperature up to 150 °C compared with traditional polystyrene MLA, is demonstrated. This precision imprinted wood may open new possibilities toward environmentally friendly devices and applications in optics, biology, electronics, etc.

The influence on modal parameters of thin cylindrical shell (TCS) under bolt looseness boundary is investigated. Firstly, bolt looseness boundary of the shell is divided into two types, that is, different bolt looseness numbers and different bolt looseness levels, and natural frequencies and mode shapes are calculated by finite element method to roughly master vibration characteristics of TCS under these conditions. Then, the following measurements and identification techniques are used to get precise frequency, damping, and shape results; for example, noncontact laser Doppler vibrometer and vibration shaker with excitation level being precisely controlled are used in the test system; “preexperiment” is adopted to determine the required tightening torque and verify fixed constraint boundary; the small-segment FFT processing technique is employed to accurately measure nature frequency and laser rotating scanning technique is used to get shape results with high efficiency. Finally, based on the measured results obtained by the above techniques, the influence on modal parameters of TCS under two types of bolt looseness boundaries is analyzed and discussed. It can be found that bolt looseness boundary can significantly affect frequency and damping results which might be caused by changes of nonlinear stiffness and damping and in bolt looseness positions.

Plasmonic metal nanoparticles are a category of plasmonic materials that can efficiently convert light into heat under illumination, which can be applied in the field of solar steam generation. Here, this study designs a novel type of plasmonic material, which is made by uniformly decorating fine metal nanoparticles into the 3D mesoporous matrix of natural wood (plasmonic wood). The plasmonic wood exhibits high light absorption ability (≈99%) over a broad wavelength range from 200 to 2500 nm due to the plasmonic effect of metal nanoparticles and the waveguide effect of microchannels in the wood matrix. The 3D mesoporous wood with numerous low-tortuosity microchannels and nanochannels can transport water up from the bottom of the device effectively due to the capillary effect. As a result, the 3D aligned porous architecture can achieve a high solar conversion efficiency of 85% under ten-sun illumination (10 kW m−2). The plasmonic wood also exhibits superior stability for solar steam generation, without any degradation after being evaluated for 144 h. Its high conversion efficiency and excellent cycling stability demonstrate the potential of newly developed plasmonic wood to solar energy-based water desalination.

In this work, a hierarchically porous and ultrathick “breathable” wood-based cathode for high-performance Li-O2 batteries is developed. The 3D carbon matrix obtained from the carbonized and activated wood (denoted as CA-wood) serves as a superconductive current collector and an ideal porous host for accommodating catalysts. The ruthenium (Ru) nanoparticles are uniformly anchored on the porous wall of the aligned microchannels (denoted as CA-wood/Ru). The aligned open microchannels inside the carbon matrix contribute to unimpeded oxygen gas diffusion. Moreover, the hierarchical pores on the microchannel walls can be facilely impregnated by electrolyte, forming a continuous supply of electrolyte. As a result, numerous ideal triphase active sites are formed where electrolyte, oxygen, and catalyst accumulate on the porous walls of microchannels. Benefiting from the numerous well-balanced triple-phase active sites, the assembled Li-O2 battery with the CA-wood/Ru cathode (thickness: ≈700 µm) shows a high specific area capacity of 8.58 mA h cm−2 at 0.1 mA cm−2. Moreover, the areal capacity can be further increased to 56.0 mA h cm−2 by using an ultrathick CA-wood/Ru cathode with a thickness of ≈3.4 mm. The facile ultrathick wood-based cathodes can be applied to other cathodes to achieve a super high areal capacity without sacrificing the electrochemical performance.

Composite materials with ordered microstructures often lead to enhanced functionalities that a single material can hardly achieve. Many biomaterials with unusual microstructures can be found in nature; among them, many possess anisotropic and even directional physical and chemical properties. With inspiration from nature, artificial composite materials can be rationally designed to achieve this anisotropic behavior with desired properties. Here, a metallic wood with metal continuously filling the wood vessels is developed, which demonstrates excellent anisotropic electrical, thermal, and mechanical properties. The well-aligned metal rods are confined and separated by the wood vessels, which deliver directional electron transport parallel to the alignment direction. Thus, the novel metallic wood composite boasts an extraordinary anisotropic electrical conductivity (σ|| /σ⊥ ) in the order of 1011 , and anisotropic thermal conductivity (κ|| /κ⊥ ) of 18. These values exceed the highest reported values in existing anisotropic composite materials. The anisotropic functionality of the metallic wood enables it to be used for thermal management applications, such as thermal insulation and thermal dissipation. The highly anisotropic metallic wood serves as an example for further anisotropic materials design; other composite materials with different biotemplates/hosts and fillers can achieve even higher anisotropic ratios, allowing them to be implemented in a variety of applications.

Due to high volumes of production from the consumer electronics industry, it is highly desirable to develop green electronics comprised of biodegradable components derived from cheap resources or even agro-industrial wastes. In this work, a facile and benign production route is proposed to transform the agro-industrial waste sugarcane bagasse into value-added super-clear nanopaper for flexible and transparent electronics. High-value cellulose nanocrystals (CNCs) are isolated from abundant and inexpensive sugarcane bagasse by a one-step 2,2,6,6-tetramethylpiperidine-1-oxyl treatment, and the obtained CNCs are then used to fabricate a super-clear nanopaper substrate for next-generation flexible electronics. The super-clear nanopaper exhibits superior optical properties (91% transmittance and 1.4% transmission haze at 600 nm), excellent nanometer-scale surface roughness (3.08 nm), and good oxygen barrier properties (1.2 cm3 µm (m2 day kPa)−1 at 50% relative humidity). Moreover, proof-of-concept field-effect transistors with an on/off ratio of >103 are demonstrated on this super-clear nanopaper. The efficient and scalable production of value-added CNCs from bagasse waste coupled with advanced applications of CNC-based super-clear nanopaper in electronic devices presents a solution for the conversion of agricultural wastes to value-added electronic applications, which is beneficial for green electronics and recycling and ecoindustries.

A highly efficient 3D wood-derived carbon monolith reactor with a low tortuosity is demonstrated for high-temperature reaction applications, using catalytic steam reforming of biomass tar as the model system. Outstanding catalytic activity is achieved as the reactant gases flow through this 3D natural wood-derived catalyst, where over 99% toluene conversion and good stability at 700 °C are observed.

Among many other requirements, energy efficient building materials require effective daylight harvesting and thermal insulation to reduce electricity usage and weatherization cost. The most commonly used daylight harvesting material, glass, has limited light management capability and poor thermal insulation. For the first time, transparent wood is introduced as a building material with the following advantages compared with glass: (1) high optical transparency over the visible wavelength range (>85%); (2) broadband optical haze (>95%), which can create a uniform and consistent daylight distribution over the day without glare effect; (3) unique light guiding effect with a large forward to back scattering ratio of 9 for a 0.5 cm thick transparent wood; (4) excellent thermal insulation with a thermal conductivity around 0.32 W m−1 K−1 along the wood growth direction and 0.15 W m−1 K−1 in the cross plane, much lower than that of glass (≈1 W m−1 K−1); (5) high impact energy absorption that eliminates the safety issues often presented by glass; and (6) simple, scalable fabrication with reliable performance. The demonstrated transparent wood composite exhibits great promise as a future building material, especially as a replacement of glass toward energy efficient building with sustainable materials.

Sodium-ion batteries (SIBs) have attracted extensive interest in the past few years because of the low cost and abundance of sodium resources and hence the potential for grid scale energy storage. Developing low cost electrode materials, particularly anode materials, is the key for further promoting the application of SIBs. Here, we for the first time report a self-standing porous carbon anode directly from natural wood for SIBs, which processes following advantages: (i) ultra-thick carbon anode with a high areal capacity, for example a capacity of 13.6 mAh cm-2 was delivered when the thickness reached 0.85 mm; (ii) low tortuosity, where numerous inherited aligned channels in the wood carbon provide a rapid ion transport path; (iii) porous nature enables a fast ion transfer between the carbon electrode and the electrolyte; (iv) 100% utilization of the wood carbon that conductive additives, binders, and current-collectors are not needed; v) when coupling a Na3V2(PO4)3 cathode with the wood carbon anode, a high capacity of 80 mAh g-1 was obtained at 0.5 C rate (base on cathode) and excellent cycling stability of 300 cycles was also achieved, which demonstrated the promising performance of earth-abundant wood derived carbon material.