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In this work, a novel bamboo-like carbon nanotubes@Sn4P3@carbon (BLCNTs@Sn4P3@C) coaxial nanotubes are designed and prepared using a newly developed hydrothermal method followed by a phophidation process. The prepared Sn4P3 nanoparticles are uniformly coated and wrapped on the one-dimensional (1D) bamboo-like CNTs, which is covered by a uniform carbon layer to form a sandwich-like structure with Sn4P3 in between. The inner CNT and outer carbon can effectively maintain the structural stability and serve as the good electron conductors. Additionally, the outer carbon coating layer can effectively keep BLCNTs@Sn4P3@C nanotubes separate each other, preventing aggregation of Sn4P3 during charge/discharge when this material is used as anode for sodium ion batteries. The anode of BLCNTs@Sn4P3@C shows excellent reversible capacity and a long cycling of over 2000 cycles. The unique design of coaxial nanotubes is greatly beneficial to the electrochemical performance of Sn4P3 for sodium ion storage.

Evidential reasoning (ER) rule has been widely used in dealing with uncertainty. As an important parameter to measure the inherent property of evidence, the evidence reliability makes the ER rule constitute a generalized reasoning framework. In current research of the ER rule, the evidence reliability tends to be expressed in the form of quantitative value by certain methods or expert knowledge. The single quantitative value lacks the ability to describe the statistical property of reliability, which leads to unreasonable results. In this article, a new ER rule with continuous probability distribution of reliability denoted by ERr-CR is proposed. The combination of two pieces of evidence is discussed in detail, where the reliability is profiled as random variables with specific probability distribution. To characterize the output of ERr-CR, a novel concept of expectation of the expected utility is proposed. In addition, the ERr-CR is expanded to multiple pieces of evidence to show its universality. Further, the basic performances of the ERr-CR are explored to illustrate the rationality. Moreover, a case study of safety assessment of natural gas storage tanks (NGSTs) is conducted to show the potential applications of ERr-CR, which makes the proposed method more practical.

Studies on the formation and evolution of the solid electrolyte interface (SEI) film under different ambient temperatures are important to understand the failure behavior of lithium-ion batteries (LIBs). Herein, in-situ electrochemical impedance spectroscopy (EIS) test is performed on the whole discharge process of Si@Graphite@C/Li cell at 0, 25 and 55 ℃, respectively. Combining with scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy characterizations, it is found that the SEI film undergoes a complicated evolution process of pre-formation, self-improvement and gradual decay in succession at 25 ℃. Besides, due to the dissolution of organo-alkyl lithium at high temperature, the formed film is mainly composed of LiF, Li2CO3 and other inorganic salts, which helps to decrease the impedance. However, the electrolyte is consumed continuously on the new exposed interface, leading to the degraded performance of the cell. Moreover, the dynamic properties of Li+ ions are poor at low temperature, though the migration ability of Li+ ions in the solid phase can be improved as the cycle goes on. Therefore, the development and application of in-situ EIS technology are expected to become an important means to explain the electrochemical performance of batteries.

Numerous strategies for linking desired chemical probes with target peptides and proteins have been developed and applied in the field of biological chemistry. Approaches for site-specific modification of native amino acid residues in test tubes and biological contexts represent novel biological tools for understanding the role of peptides and proteins. Selective N-terminal modification strategies have been broadly studied especially in the last 10 years, as N-terminal positions are typically solvent exposed and provide chemically distinct sites for many peptide and protein targets, making N terminus distinct from other functional groups. A growing number of chemical and enzymatic techniques have been developed to modify N-terminal amino acids, and those techniques have the potential in the fields of medicine, basic research and applied materials science. This review focuses on appraising modification methodologies with the potential for biological applications from the past 10 years.

It is desirable to develop highly efficient and sustainable catalytic systems for CO2 photoreduction using efficient heterogeneous photosensitizers (PSs); however, this remains a great challenge. In this study, we doped [Ru(bpy)3]2+ into UiO-metal-organic frameworks (MOFs) to facilitate the separation and reuse of noble metal PS. By simply adjusting the loading amount, a series of heterogeneous photoactive MOFs, namely, UiO-Ru-1, UiO-Ru-2, and UiO-Ru-3, were constructed to act as heterogeneous PSs to drive the efficient CO2 photoreduction under visible-light irradiation. Remarkably, UiO-Ru-2 exhibited the best photosensitizing ability among the prepared MOFs in sensitizing the iron quarterpyridine catalyst (C-1), and the CO yield reached as high as 171 mmol/g with ca. 100% selectivity, which is a record value among all the MOF-based photocatalysts. This photoactive MOF can be recycled and reused three times without any obvious activity loss, signifying its good photochemical stability. Experimental investigations confirmed that the strong visible absorption, long-lived excited state, appropriate redox potential, good photocatalytic stability, and excellent collaboration with C-1 were attributable to the superior catalytic activity. This work highlights an avenue for constructing heterogeneous PSs with excellent recyclability using MOF as the platform for efficient CO2 reduction.

This paper investigates an iterative learning control scheme for a 5 degrees of freedom upper-limb exoskeleton with time-varying constraints. No priori knowledge of nonlinear dynamic parameters is needed in the modeling process by applying the iterative recursive method, thereby the time-consumption modelling work can be averted. Unlike most iterative learning algorithms that require identical initial condition between different iterations, the estimation errors of learning part in our work can be arbitrary small along the iterations under random initial status. To further improve the safety of human-robot system, a tan-type barrier Lyapunov function is utilized in convergence analysis to guarantee the constraint requirements of tracking errors between human body and robot. Furthermore, in order to handle the nonparametric uncertainties and external disturbances, sliding mode control strategy is constructed where the chattering phenomenon in control torques is suppressed by adaptive method. The stability over the time domain and convergence over the iterative domain are proved by composite energy function. Finally, comparative study and co-simulation results of Matlab/Simulink and ADAMS are presented to verify the advantages and effectiveness of proposed algorithm.

Taking advantage of the magnetic field inside transmission electron microscope (TEM), a unique Lorentz-force-actuated method for quantitative friction tests was developed via a commercial electromechanical holder. With this approach, a submicron-sized silver asperity sliding on a tungsten flat punch was actuated by Lorentz force due to electrical current through the punch, with the normal force imposed by the built-in transducer of the holder. The friction force was determined by tracking the elastic deflection of the fabricated cantilever from in situ video. Through correlating the friction behavior with the microstructural evolution near the silver-tungsten interface, we revealed that even when the relative motion commenced with the plastic deformation of the silver asperity, the interface can still sustain the further increasing static friction force. Exactly following the arrival of the maximum static friction force, the sliding occurred at the interface, indicating the transition from static to dynamic friction. This work enriches our understanding of the underlying physics of the dynamic friction process for metallic friction behavior.

Low ductility and strength are major bottlenecks against Mg alloys’ wide applications. In this work, we systematically design the composition and fabrication process for a low-alloyed Mg-Zn-Ca alloy, showing that it can be extruded at low temperatures (∼250 ℃) and high speeds (∼2 mm/s). After the extrusion, this alloy exhibits a substantially weakened basal texture, relatively small grain size, very high tensile elongation (∼30%), and good strength. The origin of the considerably improved ductility was studied using a combination of three-dimensional atom probe tomography (3D-APT), transmission electron microscopy (TEM), electron backscattered diffraction (EBSD) in conjunction with surface slip trace analysis, in-situ synchrotron X-ray diffraction, and elasto-plastic self-consistent (EPSC) modeling. Co-segregation of Zn and Ca atoms at a grain boundary is observed and associated with texture weakening and grain boundary mediated plasticity, both improving the ductility. While basal slip and prismatic slip are identified as the dominant deformation systems in the alloy, the ratio between their slip resistances is substantially reduced relative to pure Mg and most other Mg alloys, significantly contributing to the improved ductility of the alloy. This Mg-Zn-Ca alloy exhibiting excellent mechanical properties and low fabrication cost is a promising candidate for industrial productions.

Urban land-use maps outlining the distribution, pattern, and composition of various land use types are critically important for urban planning, environmental management, disaster control, health protection, and biodiversity conservation. Recent advances in remote sensing and social sensing data and methods have shown great potentials in mapping urban land use categories, but they are still constrained by mixed land uses, limited predictors, non-localized models, and often relatively low accuracies. To inform these issues, we proposed a robust and cost-effective framework for mapping urban land use categories using openly available multi-source geospatial “big data”. With street blocks generated from OpenStreetMap (OSM) data as the minimum classification unit, we integrated an expansive set of multi-scale spatially explicit information on land surface, vertical height, socio-economic attributes, social media, demography, and topography. We further proposed to apply the automatic ensemble learning that leverages a bunch of machine learning algorithms in deriving optimal urban land use classification maps. Results of block-level urban land use classification in five metropolitan areas of the United States found the overall accuracies of major-class (Level-I) and minor-class (Level-II) classification could be high as 91% and 86%, respectively. A multi-model comparison revealed that for urban land use classification with high-dimensional features, the multi-layer stacking ensemble models achieved better performance than base models such as random forest, extremely randomized trees, LightGBM, CatBoost, and neural networks. We found without very-high-resolution National Agriculture Imagery Program imagery, the classification results derived from Sentinel-1, Sentinel-2, and other open big data based features could achieve plausible overall accuracies of Level-I and Level-II classification at 88% and 81%, respectively. We also found that model transferability depended highly on the heterogeneity in characteristics of different regions. The methods and findings in this study systematically elucidate the role of data sources, classification methods, and feature transferability in block-level land use classifications, which have important implications for mapping multi-scale essential urban land use categories.

MoSi2 and Si–MoSi2 coatings were deposited on TZM alloy by using a hot dip silicon-plating method. The composite coatings mainly consist of MoSi2 and Si with a small amount of C/SiO2/ZrSi2. The composite coatings have fine MoSi2 grain size and higher surface silicon concentration. The diffusion layer mainly consists of MoSi2 layer and Mo5Si3C layer under the deposition time is 10 min. The diffusion layer is divided into three layers when the deposition time ranges from 15 to 25 min, which consists of Si–MoSi2 layer, MoSi2 layer and Mo5Si3 interface layer. The gradient structure can reduce the stress mutation between coating and the substrate, and further reduce the possibility of crack propagation. SEM and CLSM results show that a large amount of MoSi2 grains are covered by a silicon layer when the deposition time is longer than 10 min, which results in a very low coating surface roughness. And the lowest values of Sa and Sq are 0.292 and 0.391 μm, respectively. Meanwhile, about 65.375%–79.898% of the coating surfaces are covered by silicon when the deposition time is 20–25 min.

Drought is one of the most critical abiotic stresses influencing maize yield. Improving maize cultivars with drought tolerance using marker-assisted selection requires a better understanding of its genetic basis. In this study, a doubled haploid (DH) population consisting of 217 lines was created by crossing the inbred lines Han 21 (drought-tolerant) and Ye 478 (drought-sensitive). The population was genotyped with a 6 K SNP assay and 756 SNP (single nucleotide polymorphism) markers were used to construct a linkage map with a length of 1344 cM. Grain yield (GY), ear setting percentage (ESP), and anthesis–silking interval (ASI) were recorded in seven environments under well-watered (WW) and water-stressed (WS) regimes. High phenotypic variation was observed for all traits under both water regimes. Using the LSMEAN (least-squares mean) values from all environments for each trait, 18 QTL were detected, with 9 associated with the WW and 9 with the WS regime. Four chromosome regions, Chr. 3: 219.8–223.7 Mb, Chr. 5: 191.5–194.7 Mb, Chr. 7: 132.2–135.6 Mb, and Chr. 10: 88.2–89.4 Mb, harbored at least 2 QTL in each region, and QTL co-located in a region inherited favorable alleles from the same parent. A set of 64 drought-tolerant BC3F6 lines showed preferential accumulation of the favorable alleles in these four regions, supporting an association between the four regions and maize drought tolerance. QTL-by-environment interaction analysis revealed 28 edQTL (environment-dependent QTL) associated with the WS regime and 22 associated with the WW regime for GY, ESP, and ASI. All WS QTL and 55.6% of WW QTL were located in the edQTL regions. The hotspot genomic regions identified in this work will support further fine mapping and marker-assisted breeding of drought-tolerant maize.

The current strategy of electrocatalytic CO2 reduction reaction (eCO2RR) to generate useful chemicals and hydrocarbons is supposed to effectively mitigate the greenhouse effect. The practical application for eCO2RR in aqueous solutions, however, still was encumbered by its high overpotential, low activity and poor selectivity due to CO2 mass transfer and intermediate stability. Electrocatalytic materials with reduced overpotential and high efficiency and selectivity are exploited for further development. Herein, Ag+ and Cu2+ precursors were co-reduced to generate Ag-Cu bimetallic aerogel after further freeze drying. Compared with Ag100 aerogel, the optimal Ag88Cu12 can effectively decrease overpotential, improve selectivity and current density, and keep electrochemical stability. At −0.89 V vs. RHE, the Faraday efficiency reached 89.40% and the CO partial current density of −5.86 mA cm−2 was obtained. The intrinsic property of metal aerogel (hydrophobic, hierarchical porous structure, conductivity), presence of rich grain boundaries and geometric effect and the introduction of Cu leading to improvement of adsorption between the catalyst and the *COOH intermediate in Ag88Cu12, contribute to the enhanced performance. Furthermore, the strategy of constructing metal aerogel will improve metal catalyst performance towards eCO2RR and pave way for further industrial applications.

Nitrogen-doped carbon materials with vacancies/defects have been developed as highly efficient ORR electrocatalysts but with poor activity for OER, which limits their application in rechargeable metal-air batteries. Filling the vacancies/defects with heteroatoms is expected to be an effective strategy to obtain surprising catalytic activities and improve their stability especially under the strongly oxidizing conditions during the OER process. Herein, we successfully transformed the defect-rich 3D carbon nanosheets (DCN) into a bifunctional ORR/OER electrocatalyst (DCN-M) by utilizing the in-situ generated vacancies to capture metal cations via a modified salt-sealed strategy. By varying the metal (Fe, Ni) content, the captured metal cations in DCN-M existed in different chemical states, i.e., metal atoms were stabilized by C−N bonds at low metal contents, while at high metal contents, bimetal particles were covered by graphene layers, taking responsibility for catalyzing the ORR and OER, respectively. In addition, the in-situ formed graphene layers with an interconnected structure facilitate the electron transport during the reactions. The Janus-feature of DCN-M in structures ensures superior bifunctional activity and good stability towards ORR/OER for the rechargeable Zn-air battery. This work provides an effective strategy to design multifunctional electrocatalysts by heteroatom filling into vacancies of carbon materials.

The ramjet/scramjet engines require the control-oriented model to predict the inlet flow field in less than a few seconds. However, it is challenging for these kinds of inlets which utilize curved shock waves to compress the air flow. In this paper, a reduced-order model based on the computational fluid dynamics, the proper orthogonal decomposition theory, and the radial basis function interpolation method is developed. After that, the curved shock waves dominated flow fields of a ramjet inlet under different angles of attack and free stream Mach numbers are predicted with this reduced-order model and compared to the full order computational fluid dynamics solutions. The results show that this reduced-order model can successfully predict the curved shock waves, the curved shock wave/boundary layer interactions, and the shock trains caused by a back pressure with high accuracies. The consumed time is only 0.11 s. The performance parameters are also predicted with the relative errors no more than 2%.

(1−x)K0.5Na0.5NbO3−xBi(Zn2/3Nb1/3)O3 ((1−x)KNN−xBZN, x = 0.010, 0.015, 0.020, 0.025, and 0.030) lead-free ceramics were fabricated via a traditional solid-state method. The crystal structure, microstructure, dielectric, and conductivity behavior of this system were studied. Combined with X-ray diffraction (XRD) patterns, Rietveld refinement, and dielectric spectroscopy, an orthorhombic phase was determined for x = 0.010, an orthorhombic-tetragonal mixed phase was identified for x = 0.015, and a rhombohedral symmetry appears in 0.020 ⩽ x ⩽ 0.030. Both 0.98KNN−0.02BZN and 0.975KNN−0.025BZN ceramics exhibit stable permittivity and low dielectric loss tangent (tanδ) in wide temperature ranges owing to the combination of rhombohedral-tetragonal step-like feature and the diffuse phase transition from tetragonal to cubic. The activation energies of dielectric relaxation and conductivity behavior at high temperatures initially decrease slightly, then drop sharply, and finally decline slowly, which could be attributed to microstructure morphologies and the concentration of oxygen vacancies.

Adzuki bean (Vigna angularis (Willd.) Ohwi & Ohashi) is an annual cultivated leguminous crop commonly grown in Asia and consumed worldwide. However, there has been limited research regarding adzuki bean genetics, which has prevented the efficient application of genes during breeding. In the present study, we constructed a high-density genetic map based on whole genome re-sequencing technology and validated its utility by mining QTLs related to seed size. Moreover, we analyzed the sequences flanking insertions/deletions (InDels) to develop a set of PCR-based markers useful for characterizing adzuki bean genetics. A total of 2904 markers were mapped to 11 linkage groups (LGs). The total length of the map was 1365.0 cM, with an average distance between markers of 0.47 cM. Among the LGs, the number of markers ranged from 208 (LG7) to 397 (LG1) and the total distance ranged from 97.4 cM (LG9) to 155.6 cM (LG1). Twelve QTLs related to seed size were identified using the constructed map. The two major QTLs in LG2 and LG9 explained 22.1 and 18.8% of the total phenotypic variation, respectively. Ten minor QTLs in LG4, LG5 and LG6 explained 3.0–10.4% of the total phenotypic variation. A total of 9718 primer pairs were designed based on the sequences flanking InDels. Among the 200 selected primer pairs, 75 revealed polymorphisms in 24 adzuki bean germplasms. The genetic map constructed in this study will be useful for screening genes related to other traits. Furthermore, the QTL analysis of seed size and the novel markers described herein may be relevant for future molecular investigations of adzuki bean and will be useful for exploiting the mechanisms underlying legume seed development.

Solar energy is an ideal energy source for solving energy shortages and serious environmental problems. In the past few decades, photocatalytic technology which uses solar energy to deal with the above problems has caused great interest. ZnIn2S4, as a layered ternary metal chalcogenide compound, has a series of advantages such as the wide light absorption range and adjustable bandgap. It has been applied in the different fields of photocatalysis in recent years. This review introduced the crystal structures and growth mechanism of ZnIn2S4 and summarized the preparation methods of ZnIn2S4. Also, the promoted strategies of ZnIn2S4 based photocatalytic system and their applications in the pollutant removal, hydrogen evolution, reduction of CO2, nitrogen fixation, and chemical synthesis was summarized. Furthermore, the challenges and development directions of the current ZnIn2S4 based photocatalytic system were proposed. It is hoped that this review will help researchers design a better ZnIn2S4 based photocatalytic system.

Vibration energy harvesting has extensive application prospects in many significant occasions, such as mechanical structure health monitoring, vehicle tire pressure monitoring, IoT devices and human health monitoring. The nonlinearity is an effective method to improve the energy harvesting efficiency where there are low- and high-energy orbits in the multi-solution region of the system. The harvested power will be increased significantly when the system is guided from the low-energy orbit to the high-energy orbit. However, previous research mainly focuses on the theoretical and numerical investigation of controlling strategy, but the feasibility of control methods has not been verified experimentally. This paper proposes a high-energy sliding mode control method through rotatable magnets actuated by micro-motor. The electromechanical model of mono-stable and bi-stable systems with the identified nonlinear restoring force is established to design a sliding mode control algorithm for enhancing the energy harvesting performance. Simulation and experiment results demonstrate that the rotatable magnets with sliding mode control have a positive influence on reaching the high-energy orbit for both mono-stable and bi-stable systems within the multi-solution region. Moreover, the rotatable magnets method with a sliding mode control actuates the small magnets in the system for a short time with little consumption of energy. This research has provided a practical application of high-energy orbit control for improvement of the energy harvesting.

Oyster is rich in plasmalogens that are ether phospholipids with biological functions to human body. Air-frying is a popular technique for preparing delicious oyster but makes the plasmalogens vulnerable to oxidation. In this study, the effect of air-frying processing on plasmalogens oxidation was studied by lipidomic approach. Plasmalogens were always mixed with normal phospholipids, thus the lipid extract was treated with mild acid hydrolysis to rapidly degrade plasmalogens owing to the acid lability of vinyl ether linkage at sn-1 position. After hydrophilic interaction chromatography MS/MS analysis, there were three plasmalogen classes, plasmanylcholine, plasmanylethanolamine, and plasmanylinositol, completely separated, and each plasmalogen molecular species was identified and quantified. It indicated that the content of plasmalogens underwent an obvious decrease during the air-frying process. To weaken such effect, the influence of air-frying temperature was further inspected by multivariate statistical analyses. The main variables, including the ions of m/z 756.4927, 784.5486, 828.5812, etc., were revealed by unsupervised principle component analysis, supervised orthogonal partial least-square analysis, and variable importance in projection plot. As a conclusion, air-frying has health benefits in reducing fat content but destructive to plasmalogens, thus interventions are recommended to prevent the degradation of plasmalogens.

Nitrogen (N) fertilizer is applied to the soil to increase the nutrient level and plant productivity, but the effects of N addition on the soil microbial community diversity and functions are unclear. This study aimed to determine how changes in soil N influence soil microbial community diversity and potential functions. We evaluated plant characteristics, soil chemical properties, microbial composition, and potential functions (N-fixation and functional fungal guild) after 3 years of urea fertilization at four different levels (0, 25, 50, and 100 kg N ha−1 year−1) in a semiarid grassland in China. Compositions of bacterial and fungal communities were determined by high-throughput sequencing, and their potential functions were predicted by comparing their data with those in the Tax4Fun and FUNGuild databases, respectively. Compared with the grassland without N input (N0), N fertilization significantly reduced soil bacterial diversity, possibly by reducing plant diversity. Fungal diversity increased with N fertilization and peaked in the N50 treatment, while the aboveground biomass showed a parallel increase and peak. A lower abundance of nif genes was found in the N100 than in the N0 treatment because the enhanced NO3− and NH4+ content alleviated the dependence of plants on biological N-fixation and reduced the N-fixation potential. N fertilization increased the relative abundance of saprotrophs (wood, plant, and dung saprotrophs) and pathogens (plant and animal pathogens). However, this promotion could be weakened when the excessive N fertilization was applied due to the lower abundance in the N100 than in the N50 treatment, and these changes could be attributed to the variation in aboveground biomass and soil organic C. Changes in the abundance of arbuscular mycorrhizal fungi were related to their host plants, exhibiting a transient increase in the N25 compared to the N0 treatment and then sharply decreasing. Our results show that N-induced environmental changes have considerable influence on the composition and potential functions of soil bacterial and fungal communities, which are likely to be dependent on interactions between plants and soil.

To investigate the price fluctuation mechanism of stock markets, this research aims to develop a novel stochastic financial model based on Potts dynamics and compound Poisson process. The new model considers two aspects: information interaction among traders and the uncertain events outside the system. Then, three different volatility statistics (return series $$r_t$$ , absolute return series $$|r_t|$$ and volatility duration average intensity $$V_t$$ ) are introduced to explore the volatility and complexity properties of the proposed model. The descriptive statistical methods, such as basic statistical properties and distribution analysis, are studied to validate the practicable of the proposed stochastic financial model. The permutation Lempel-Ziv complexity of moving average series is referred to different volatility sequences to evaluate the complexity of the simulative data from proposed model and the real data from stock market. Moreover, the complexity analysis of fractional sample entropy and multiscale fractional sample entropy is improved to illustrate the complexity of volatility behaviors in different scales. Compared with the real stock data, the empirical results demonstrate that the new model could reproduce the fluctuation and volatility behaviors of real stock markets to some extent.

The reverse logistics of municipal hazardous waste (RLMHW) have received close attention from researchers and practitioners alike, given the essential impact of safe transportation and effective management of hazardous waste on public health and environmental sustainability. There are a great number of studies in the extant literature on RLMHW, with many and diverse research topics; however, a concise and complete overview of the research works already conducted in this particular area is conspicuous by its absence. This paper strives to fill the gap through the conduct of rigorous systematic literature review of RLMHW in the past three decades, and then establish a framework of studies on RLMHW. The main contributions of this study are as follows: (1) to identify the trend of journals publishing research papers on RLMHW; (2) to extract the main topics in studies on RLMHW; (3) to locate the most popular research areas of RLMHW; (4) to summarize the methods adopted in studies on RLMHW; (5) to identify research deficiencies in certain categories of RLMHW; and (6) to establish the future research directions of RLMHW. The main implications of the study are to offer a better understanding of RLMHW by systematic crystallization of archival data in a systematic chronological order across central issues. This study contributes to scholarly debate in this field by serving as a snapshot paper to document the development of the field and gives input to policymakers in process design and policy making in the domain of RLMHW.

Summary Water-wave energy, as one of the important renewable energies, is greatly difficult to efficiently harvest due to its characteristics of low frequency and randomly moving direction. Herein, we report an active resonance triboelectric nanogenerator (AR-TENG) system fabricated by using simple pendulum, tumbler, and flexible ring TENG, which can harvest omnidirectional and frequency varying water-wave energy through excellent structural design and resonance effect. Besides, thanks to the high-frequency damped motion of simple pendulum and tumbler, the high-frequency output generated by the AR-TENG system under the driving condition of low-frequency water wave can greatly improve the efficiency of wave energy harvesting. More importantly, based on the low damping coefficient, resonance effect, and elimination of water screening effect, the output performance of AR-TENG system in the water wave is closest to the simulated test. This work not only can realize the omnidirectional water-wave energy harvesting by TENG but also provide a method for large-scale blue energy harvesting.

Photosystem I (PSI) is one of the two photosystems in photosynthesis, and performs a series of electron transfer reactions leading to the reduction of ferredoxin. In higher plants, PSI is surrounded by four light-harvesting complex I (LHCI) subunits, which harvest and transfer energy efficiently to the PSI core. The crystal structure of PSI-LHCI supercomplex has been analyzed up to 2.6 Å resolution, providing much information on the arrangement of proteins and cofactors in this complicated supercomplex. Here we have optimized crystallization conditions, and analyzed the crystal structure of PSI-LHCI at 2.4 Å resolution. Our structure showed some shift of the LHCI, especially the Lhca4 subunit, away from the PSI core, suggesting the indirect connection and inefficiency of energy transfer from this Lhca subunit to the PSI core. We identified five new lipids in the structure, most of them are located in the gap region between the Lhca subunits and the PSI core. These lipid molecules may play important roles in binding of the Lhca subunits to the core, as well as in the assembly of the supercomplex. The present results thus provide novel information for the elucidation of the mechanisms for the light-energy harvesting, transfer and assembly of this supercomplex.

The ability to achieve long-endurance station-keeping flights makes stratospheric airships desirable platforms for the provision of communication and surveillance services. To maintain long-endurance flights, it is necessary to consider the problem of energy consumption. In this paper, we discuss long-endurance flight scenarios of stratospheric airships in the presence of thermal effects. The balance between buoyancy and gravity is influenced by thermal effects during the diurnal cycle. We perform a theoretical analysis based on the helium’s mass, pressure differential, and altitude as the main factors. To verify the effectiveness of the control over the pressure differential and the altitude, three long-endurance flight scenarios are proposed and compared. Then, the corresponding optimization problems are constructed to determine the energy-minimum flight. Finally, further efforts are made to reduce energy consumption. The realization and limitations of two strategies for improvement are analyzed. A comparison with other scenarios shows the effectiveness of energy conservation. The study in this paper thus provides a reference for station-keeping applications of stratospheric airships.

As particular cubic perovskite-type materials, copper tantalate Cu2Ta4O12 (CTO) displays a giant-dielectric phenomenon. A thermal-treatment method for enhancing the dielectric response of CTO is developed. The air-quenching Cu2Ta4O12 (CTOq) and slowing-furnace-cooling Cu2Ta4O12 (CTOs) were fabricated and identified with cubic crystal structure. The CTOs sample shows a colossal permittivity (104 - 107) in a broad frequency (40 Hz–105 Hz) and temperature region (300 K–470 K). The permittivity dependence of frequency for CTOq and CTOs samples were described by the Maxwell-Wagner relaxation and Cole-Cole relation. The low-frequency dielectric response associates with the internal barrier layer capacitor effect intensified by oxygen vacancies, while in the high-frequency range it is mainly involved in the relaxation induced by charged point defects in grains. The concentration of the point defects was evidenced by XPS with Cu+, Cu2+ and oxygen. The impedance, electrical modulus and conductivity behavior of the samples at selected temperature were also described. The results indicate that the colossal permittivity response is related to interaction mechanism of point defects and grain boundaries, which can be modified by the thermal treatment process.

Hydrogen evolution reaction (HER), has been considered as an ideal alternative energy system to alleviate the global energy crisis. Unfortunately, the rational design of a cost-effective, highly active and stable electrocatalyst remains a tough challenge. In this work, a CO2 assisted synthesis of N- doped carbon aerogel derived from silk fibroin (SFCA) without any additives was used to anchor Nickel–Cobalt (NiCo) nanoparticles as an HER electrocatalyst in basic medium (1 M KOH). The obtained SFCA-NiCo electrocatalyst demonstrated outstanding electrochemical performance having an onset potential of 52 mV and a low overpotential of 179 mV at current density of 10 mA cm−2, whilst exhibiting long term stability when tested for 24 h. The outstanding electrocatalytic performance marks SFCA-NiCo as a favourable electrocatalyst for HER and the synthesis strategy paves way for constructing novel catalysts even for other areas.

Metal-organic chemical vapor deposition (MOCVD) is a key technique for developing and manufacturing zinc oxide (ZnO) devices. The film quality and performance of these devices are influenced by the process parameters. In this study, the film deposition rate and film uniformity obtained from the simulations and experiments under different process parameters, such as the substrate temperature, operating pressure, mass fraction of the source gas, and inlet flow rate, are compared and verified. In addition, the corresponding temperature field, flow field, distribution of source mass fraction, and velocity field are analyzed using the computational fluid dynamics (CFD) method to explain the influence of the flow field change on deposition rate and film uniformity. This study also presents the correlation test for the film uniformity between the simulation and experimental results; it was found that all the 16 sets of results are significantly correlated and that more than half of them are highly correlated. To ensure the consistency of the experimental results and to prove their reliability, the repeatability test and stability test are conducted.

Urbanization has substantially changed landscape patterns and seriously disturbed the structure and function of the ecosystems. However, the spatial characteristics and relationships between landscape patterns and ecosystem service values (ESVs) along the urban-rural gradient remain unclear. Based on high-resolution images, this study used concentric buffer zones to explore the characteristics and relationship between landscape pattern indexes (LPIs) and ESVs in the rural-urban gradient to reveal the impact of urban development on urban ecosystems. The results showed that the landscape heterogeneity was high in the urban fringe 18-20 km from the urban center. The PD, ED, LSI, SHAPE_MN, DIVISION, SPLIT, and SHIDI variables had the lowest values in the urban center, while CONTAG and AI had the high values in the urban. Water bodies and forest land are the main land use/land cover (LULC) types that provide ecosystem services. The total ESV of Kunshan city totaled 5597.31 × 106 CNY in 2018. The average ESV increased from 2.42 × 106 CNY to 9.92 × 106 CNY along the urban-rural gradient, which indicated that natural landscapes had higher ESVs. ED and Landscape Division Index (DIVISION) had positive effects on ESV, while Largest Patch Index (LPI), Contagion (CONTAG), Proportion of Like Adjacencies (PLADJ), Patch Cohesion Index (COHESION), and Aggregation Index (AI) had negative effects on ESV. The results of the regression model indicated there were quantitative relationships between ESVs and LPIs, which revealed how landscape pattern affected ESVs. The study can provide a scientific reference for the optimization of urban landscape patterns and urban and rural sustainable development.

Rhodomentosones A and B (1 and 2), two pairs of novel enantiomeric phloroglucinol trimers featuring a unique 6/5/5/6/5/5/6-fused ring system were isolated from Rhodomyrtus tomentosa. Their structures with absolute configurations were elucidated by NMR spectroscopy, X-ray crystallography, and ECD calculation. The bioinspired syntheses of 1 and 2 were achieved in six steps featuring an organocatalytic asymmetric dehydroxylation/Michael addition/Kornblum-DeLaMare rearrangement/ketalization cascade reaction. Compounds 1 and 2 exhibited promising antiviral activities against respiratory syncytial virus (RSV).

The soil organic carbon (SOC) pool is larger than the biotic and atmospheric carbon pools, and understanding cultivated land SOC is critical for evaluating soil fertility and local agricultural man...

A Cd(ΙI)-based luminescent coordination polymer, namely [Cd(L)2(H2O)2]n (1), has been synthesized by 1-(tetrazo-5-yl)-4-(triazo-1-yl)benzene ligand (HL) and structurally characterized. The selectiv...

Two rearranged triterpenoids, representing new subtypes of pentacyclic triterpenoids, with unique 6/6/6/7/5 and 6/6/5/6/6/6 ring systems were isolated from Alstonia scholaris. Their structures were established by spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Both compounds exhibited potent antihyperuricemic bioactivity in vitro and in vivo.

Oxygen vacancies play a positive role in optimizing the physical and chemical properties of metal oxides. In this work, we demonstrated oxygen vacancy-promoted enhancement of Li-ion diffusion kinetics in Li2GeO3 nanoparticle-encapsulated carbon nanofibers (denoted as Li2GeO3-x/C) and accordingly boosted lithium storage. The introduction of the oxygen vacancies in Li2GeO3-x/C can enhance electronic conductivity and evidently decrease activation energy of Li-ion transport, thus resulting in evidently accelerated Li-ion diffusion kinetics during the lithiation/delithiation process. Thus, the Li2GeO3-x/C nanofibers exhibit an exceptionally large discharge capacity of 1460.5 mA h g-1 at 0.1 A g-1, high initial Coulombic efficiency of 81.3%, and excellent rate capability. This facile and efficient strategy could provide a reference for injecting the oxygen vacancies into other metal oxides for high-performance anode materials.

A class of quinazolone thiazoles was identified as new structural scaffolds for potential antibacterial conquerors to tackle dreadful resistance. Some prepared compounds exhibited favorable bacteriostatic efficiencies on tested bacteria, and the most representative 5j featuring the 4-trifluoromethylphenyl group possessed superior performances against Escherichia coli and Pseudomonas aeruginosa to norfloxacin. Further studies revealed that 5j with inappreciable hemolysis could hinder the formation of bacterial biofilms and trigger reactive oxygen species generation, which could take responsibility for emerging low resistance. Subsequent paralleled exploration discovered that 5j not only disintegrated outer and inner membranes to induce leakage of cytoplasmic contents but also broke the metabolism by suppressing dehydrogenase. Meanwhile, derivative 5j could intercalate into DNA to exert powerful antibacterial properties. Moreover, compound 5j gave synergistic effects against some Gram-negative bacteria in combination with norfloxacin. These findings indicated that this novel structural type of quinazolone thiazoles showed therapeutic foreground in struggling with Gram-negative bacterial infections.

Magnetic field-free, nonvolatile magnetic memory with low power consumption is highly desired in information technology. In this work, we report a current-controllable alignment of magnetic domain walls in a single layer La0.67Sr0.33MnO3 thin film with the threshold current density of 2 × 105 A/cm2 at room temperature. The vector relationship between current directions and domain-wall orientations indicates the dominant role of spin-orbit torque without an assistance of external magnetic field. Meanwhile, significant planar Hall resistances can be readout in a nonvolatile way before and after the domain-wall reorientation. A domain-wall-based magnetic random-access memory (DW-MRAM) prototype device has been proposed.

Cancer has become one of the most common diseases with high mortality in humans. Early and accurate diagnosis of cancer is of great significance to enhance the survival rate of patients. Therefore, effective molecular ligands capable of selectively recognizing cancer are urgently needed. In this work, we identified a new DNA aptamer named SW1 by tissue-based systematic evolution of ligands by exponential enrichment (tissue-SELEX), in which cancerous liver tissue sections were used as the positive control and adjacent normal liver tissue sections were used as the negative control. Taking immobilized liver cancer SMMC-7721 cells as the research object, aptamer SW1 exhibited excellent affinity with a Kd value of 123.62 ± 17.53 nM, and its binding target was preliminarily determined as a non-nucleic acid substance in the nucleus. Moreover, tissue imaging results showed that SW1 explicitly recognized cancerous liver tissues with a high detection rate of 72.7% but displayed a low detection rate to adjacent normal tissues. In addition to liver cancer cells and tissues, aptamer SW1 has been demonstrated to recognize various other types of cancer cells and tissues. Furthermore, SW1-A, an optimized aptamer of SW1, maintained its excellent affinity toward liver cancer cells and tissues. Collectively, these results indicate that SW1 possesses great potential for use as an effective molecular probe for clinical diagnosis of cancer.

A new perovskite oxide semiconductor, CaCu3Fe2Ta2O12, was synthesized through a high-pressure and high-temperature approach. The compound possesses an Im3 space group, where it crystallizes to an A-site-ordered but B-site partial ordered quadruple perovskite structure. Spin ordering occurs around 150 K owing to the antiferromagnetic coupling between Fe3+ spins and ferromagnetic coupling between Cu2+ spins. The room-temperature dielectric permittivity of CaCu3Fe2Ta2O12 was measured to be approximately 2500 at 1 kHz. More importantly, isothermal frequency-dielectric spectroscopy demonstrates the existence of two dielectric relaxations. Debye-like relaxation is attributed to charge carriers trapped among the oxygen vacancies at low temperatures and Maxwell-Wagner polarization relaxation at high temperatures. CaCu3Fe2Ta2O12 is a new magnetic semiconductor, where A-site ordering is intercorrelated with second-order Jahn-Teller distortion. These findings offer opportunities to design novel perovskite oxides with attractive magnetic and dielectric properties.

We have synthesized a flexible polyurethane foam composite filled with expanded vermiculite powder and covered by concave-convex structural panel in order to improve the compression and cushioning property of PU foam. Concave-convex structural panel is that fabric cubes consisting of three layers of warp-knitted spacer fabrics arranged isometric apart between two layers of low-melting-point PET fabrics and then thermally processed at 180 °C. Effects of particle size and content of expanded vermiculite powders as well as the presence of concave-convex structural panel are examined in terms of foam structure and mechanical properties of composite PU foams. Expanded vermiculite addition decreases the energy required by pore nucleation, and the higher content of expand vermiculite results in pore diameter of foam and greater compression property. Filling of 2% vermiculites makes the compression property improved by 239% at 40% strain. Moreover, the smaller size of expanded vermiculite generates smaller and denser foam pore diameter and thus strengthened compression property. Foam composite with 800-mesh expanded vermiculites show the excellent compression property that 307% higher than neat PU foam at 40% strain. Concave-convex structural panel enhanced compression properties by 852% when fabric cubes arranged 1 cm apart and cushion efficiency by 29% compared to pure PU foam when fabric cubes arranged 4 cm apart. The resultant flexible polyurethane foam can absorb 97% energy at 12 J impact level. This composite can serve as the protective materials in kindergarten and old people's home.

Nowadays, scanning induction thermography (SIT) could be efficient and practical for the inspection of elongated ferromagnetic specimens in the manufacturing process. Owing to the relative movement between the specimen and excitation coil, defect visualization and depth quantification in SIT remain challenging. Focusing on these two challenges, surface-breaking notches with different depths in a steel plate at different scanning speeds have been studied in this paper. A visualization method, including image reconstruction and Wiener filter, is proposed to realize defect visualization within 600 mm/s. Then, thermal features are extracted to realize depth quantification for notches within 3.0 mm. In addition, the effect of scanning speed on the SIT detectability is investigated and it is found that the signal-to-noise ratio (SNR) decreases significantly with increasing scanning speed.

Bearing fault diagnosis is essential for the safe and stable operation of rotating machinery. Existing methods use signals from a single dimension, limiting diagnostic generality and accuracy. To address these limitations and make improved use of signal features from multiple dimensions, a novel convolutional neural network model with multi-dimensional signal inputs and multi-dimensional task outputs called MIMTNet is proposed. First, frequency domain signals and a time frequency graph are obtained by using the short-time Fourier transform and a wavelet transform to process original time domain signals simultaneously. Then, the time domain signals, the frequency domain signals, and the time frequency graph are fed into the model and a special aggregation is performed after extracting features from the three corresponding branches. Finally, the outputs of the three-dimensional tasks are acquired by different full connection layers to process the aggregated features of bearing position, damage location within the bearing, and the damage size. Two common bearing vibration signal datasets are used to verify the generalization ability of our proposed method. And experimental results show that the proposed method effectively improves the bearing diagnosis capability of the deep learning model.

Bioorthogonal cleavage chemistry has been rapidly emerging as a powerful tool for manipulation and gain-of-function studies of biomolecules in living systems. While the initial bond formation-centered bioorthogonal reactions have been widely adopted for labeling, tracing, and capturing biomolecules, the newly developed bond cleavage-enabled bioorthogonal reactions have opened new possibilities for rescuing small molecules as well as biomacromolecules in living systems, allowing multidimensional controls over biological processes in vitro and in vivo. In this Outlook, we first summarized the development and applications of bioorthogonal cleavage reactions (BCRs) that restore the functions of chemical structures as well as more complex networks, including the liberation of prodrugs, release of bioconjugates, and in situ reactivation of intracellular proteins. As we embarked on this fruitful progress, we outlined the unmet scientific needs and future directions along this exciting avenue. We believe that the potential of BCRs will be further unleashed when combined with other frontier technologies, such as genetic code expansion and proximity-enabled chemical labeling., Bioorthogonal cleavage chemistry has been rapidly emerging as a powerful tool for manipulation and gain-of-function studies of biomolecules under living conditions.

The purpose of this study was to explore the correlation between protein oxidation and quality and to study the changes in various indexes of solar-dried shrimp (Penaeus vannamei) stored at 37°C and 20°C through vacuum packing and vacuum packaging with antipressure sterilization. The results showed that ΔE as well as TVB-N and carbonyl contents increased, whereas moisture and free thiol (SH) contents decreased with time. Furthermore, SDS-PAGE and scanning electron microscopy revealed protein degradation and damage of shrimp muscle microstructure during storage. A quality prediction model based on protein oxidation was established according to Arrhenius equation. Verification of shrimp quality prediction models revealed that the relative errors of the models based on SH and carbonyl contents were below 10%, indicating that these protein oxidation parameters can be used for reliable estimation of quality changes in dried shrimp during storage.

“Using active chemicals as excipients” refers to a preparation strategy. It makes use of the drugs owning the special physical and chemical properties as the roles of excipients to assist the preparation forming or achieve some specific drug delivery function, especially in the compound preparation. This paper proposed the concept of “using active chemicals as excipients”, expounded the advantages and potentials of “medicine as excipient’s use”, and analyzed the research status of “using active chemicals as excipients” from the aspects of chemical compound preparations and traditional Chinese medicine preparations. We classified the excipient function of drugs in formulations, and expounded the functional principles and characteristics of drugs as excipients from drug physical properties and drug dispersing forms in preparation. This preparation strategy has the advantages of reducing the amount of excipients, improving drugs compliance and reducing production costs. It is an important development direction of modern pharmaceutical preparation research and production. In a word, “using active chemicals as excipients” is a potential preparation strategy, which should be paid attention to and be implemented in the process of preparation research and development.

New benzoxazole-terminated mesogenic compounds containing tolane moiety with high birefringence and large dielectric anisotropy, namely, 2-[4-[2-[4-alkoxyphenyl]ethynyl]-2,6-difluoro-phenyl]-benzox...

Second-harmonic generation (SHG) is a kind of nonlinear optical phenomenon which has been widely used in optical devices, and factors influencing its signal are very complex. Here, taking advantage of excellent structural designability and overcoming the limitations of various coordinations of lanthanide metals, for the first time a series of lanthanide metal-organic frameworks (Ln-MOFs) with one particular ligand were synthesized and structurally characterized to study the interference of the SHG signal. The optical performance including single-photon fluorescence and SHG was collected and analyzed. It is found that all 13 kinds of Ln-MOFs can be divided into 2 crystal configurations by their individual space groups and Ln-MOFs with coordinated metal atoms from La to Tb possessing the noncentrosymmetric C2 space group exhibit the SHG property, the intensity of which depends on the type of metal atoms, the pumping wavelength, and the size of the single-crystal particles. This is the first time that the relationship between the nonlinear optical properties and the structure, metal atoms, pumping wavelength, crystal size of the whole series of Ln-MOFs is studied systematically, providing a lot of interesting results and enriching the research scope of nonlinear optics and materials science.

A large amount of dust particles produced by the wind in an open-air pile is one of the important reasons for air pollution. Studying the law of dust diffusion in local areas is of great significance for the atmospheric particulate control. In this study, a pile of sodium carbonate in a large open-air pile in Weifang, China, is regarded as the research object. The dispersion characteristics of dust particles around the pile under the action of unidirectional wind are studied through wind tunnel test and numerical simulation. The complex atmospheric environment is simplified as unidirectional wind, and the influence of different wind speeds on the dispersion of particles with diverse sizes in the pile is studied. Although a large gap exists between the assumption and the real atmospheric environment, this study provides a reference for the evaluation of the pollution scope of blowing dust and prevention and control of pollution. Results show that a high-concentration range of the dust exists near the pile behind the wind direction and may continue to spread to the height due to the influence of a whirlpool, and the dispersion distance and width can increase with the increase in wind speed. The increase in particle diameter increases the kinetic energy loss of particles for the fluid. Under the same starting speed, the dispersion distance of dust decreases with the increase in particle diameter. With the increase in particle diameter, the dust concentration distribution presents the trend of interior hollowing and high-concentration area fragmenting.

Chaenomeles speciosa (Sweet) Nakai is a dual-purpose Chinese herbal medicine and functional food favored by minorities in Southwest China, and its fruits are used for the treatment of dyspepsia, dysentery, enteritis, and rheumatism inflammation. Some diseases may be related to microbial infection; however, it is not known how the fruits possess antimicrobial activity. We evaluated the antimicrobial bioctivity of different evaluation extracts of C. speciosa fruits by in vitro and in vivo with colony-forming unit assays, and the strongest bioactive-guided fraction was selected for column chromatography (CC), UHPLC-QTOF-MS/MS, and NMR spectroscopy to confirm the chemical constituents. The most possible antimicrobial mechanism of C. speciosa fruits was explored by metabolomics approach, fluorescence microscopy imaging, and scanning electron microscopy (SEM). Thirty compounds, which were major characteristic ions of the bioactive fraction, were determined precisely. The bioactive fraction could inhibit 18 pathogenic microorganisms, significantly reduced, especially drug-resistant bacteria, compared to ampicillin sodium salt, fluconazole, and berberine chloride form; and the minimum inhibitory concentration (MIC) or minimum fungicidal concentration (MFC) values were in the range of 0.1-1 mg/mL. The compounds 2'-methoxyaucuparin (1) and oleanolic acid (20) not only have antibacterial activity but also may have synergistic effects. Further, the bioactive fraction might inhibit the biofilm formation, enhance immunity, and restore bacterial infection damage in vitro and in vivo to kill microorganisms. The data indicated that C. speciosa fruits' major bioactive fraction enriched with triterpenes, flavonoids, and phenolics could be developed as a functional supplement for individuals to prevent and treat microbial infection.

To evaluate the similarity of Huoling Shengji granule (HLG) and its placebo at both granules and solution status, the innovative methods that consist of intelligent sensory evaluation technologies and human sensory evaluation methods were developed based on critical quality attributes (CQAs) of granule. The CQAs for traditional Chinese medicine (TCM) placebo granule were mainly divided into three categories: formulation attributes, visual attributes, and attributes of taste and smell. In this investigation, the novel intelligent sensory evaluation technologies including the physical property testing apparatus, computer vision system, color card, and electronic tongue (E-tongue) were employed for characterization of CQAs of HLG and its placebo. Meanwhile, human sensory evaluation by test panels was used to description the HLG and its placebo in terms of appearance, color, taste, and smell. On that basis, the similarity of placebo to CQAs of HLG was assessed by calculating the angle cosine values. The intelligent and human sensory evaluation results showed that the similarity values of HLG and its placebo about the CQAs at granule and solution status were all close to 1, which means that the two preparations have high similarities. In this study, the established similarity evaluation methods based on the CQAs were convenient and reliable, which can be utilized to evaluate the similarity of TCM granule and their placebo at granule and solution status, and demonstrated to be well applied in placebo-controlled trials.

We developed iridium-catalyzed 2-position-selective C–H borylation of indole derivatives by modifying the structure of a bipyridine-type ligand. The yields ranged from good to excellent, even on a ...