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Based on the distributed event-triggered impulsive mechanism, the leader-following mean-square consensus of stochastic multiagent systems with randomly occurring uncertainties and randomly occurring nonlinearities is investigated for the first time in this article. In order to make better use of the limited communication resources, we proposed some novel communication rules among agents and corresponding control protocol. Moreover, some new triggering functions are designed for different types of agents, which cannot only ensure that the Zeno behavior can be excluded but also make the upper bound of impulsive interval in the total time sequence satisfy a newly proposed constraint condition. When the expected value of the triggering function of the i th agent is non-negative within an event time interval, the impulsive control will be triggered. If the system achieves the consensus, the triggering events of all agents will not occur after some time. The original system is transformed into the delay system by using the input delay approach. Based on the Lyapunov stability theory, several sufficient delay-independent criteria for mean-square consensus are derived by a class of Halanay impulsive differential inequalities. Finally, the effectiveness of theoretical results is illustrated by numerical simulation examples.

Precise delivery of therapeutic protein drugs that specifically modulate desired cellular responses is critical in clinical practice. However, the spatiotemporal regulation of protein drugs release to manipulate the target cell population in vivo remains a huge challenge. Herein, we have rationally developed an injectable and Near-infrared (NIR) light-responsive MXene-hydrogel composed of Ti3C2, agarose, and protein that enables flexibly and precisely control the release profile of protein drugs to modulate cellular behaviors with high spatiotemporal precision remotely. As a proof-of-concept study, we preloaded hepatic growth factor (HGF) into the MXene@hydrogel (MXene@agarose/HGF) to activate the c-Met-mediated signaling by NIR light. We demonstrated NIR light-instructed cell diffusion, migration, and proliferation at the user-defined localization, further promoting angiogenesis and wound healing in vivo. Our approach's versatility was validated by preloading tumor necrotic factor-α (TNF-α) into the composite hydrogel (MXene@agarose/TNF-α) to promote the pro-apoptotic signaling pathway, achieving the NIR light-induced programmed cell deaths (PCD) of tumor spheroids. Taking advantage of the deep-tissue penetrative NIR light, we could eradicate the deep-seated tumors in a xenograft model exogenously. Therefore, the proposed MXene-hydrogel provides the impetus for developing therapeutic synthetic materials for light-controlled drug release under thick tissue, which will find promising applications in regenerative medicine and tumor therapy. STATEMENT OF SIGNIFICANCE: Current stimuli-responsive hydrogels for therapeutic proteins delivery mainly depend on self-degradation, passive diffusion, or the responsiveness to cues relevant to diseases. However, it remains challenging to spatiotemporally deliver protein-based drugs to manipulate the target cell population in vivo in an "on-demand" manner. Therefore, we have rationally constructed an injectable and Near-infrared (NIR) light-responsive composite hydrogel by embedding Ti3C2 MXene and protein drugs within an agarose hydrogel to enable the remote control of protein drugs delivery with high spatiotemporal precision. The NIR light-controlled release of the growth factor or cytokine has been carried out to regulate receptor-mediated cellular behaviors under deep tissue for skin wound healing or cancer therapy. This system will provide the potential for precision medicine through the development of intelligent drug delivery systems.

BiVO4 is one of most promising photocatalytic materials. In order to avoid the pollution of NOx to the environment and high-cost during the traditional synthesis process. A novel and environmentally friendly process using liquid ball-milling one step synthesis BiVO4 via NaVO3 and Bi2O3 was first proposed. The Box-Behnken (BBD) design in response surface method (RSM) was used to optimize experimental factors affecting the conversion rate of Bi2O3. Synthesis of BiVO4 from Bi2O3 and NaVO3 is completely feasible through one-step liquid phase ball milling. The optimized values of temperature, time, NaVO3 concentration, liquid-solid ratio and ball material ratio was 77.3°C, 1.85 mol/L, 1.8 h, and 17.7, respectively, obtained the conversion ratio of Bi2O3 of 92.01%. Based on one-factor-at-a-time experiments, the conversion rate of Bi2O3 reached 91.0% under the optimum synthesis conditions (T=80 °C, t=2.0 h, CNaVO3=1.0 mol/L, L/S=20 mL/g and ball to material ratio=15). Compared with the preparation of BiVO4 without ball milling, the conversion rate of Bi2O3 is increased by 64.9% via liquid phase ball-milling. Characterization via TEM and SEM showed that BiVO4 had, dendritic shape, 200-300 nm diameter, bright yellow color, and satisfactory appearance.

The traditional standard compound parabolic concentrator (S-CPC) lacks flexibility in production and application due to its high-precision curved surface structure, and the extremely non-uniform flux distribution on the absorber greatly affects the stability of system. A novel method for performance optimization design of multi-sectioned compound parabolic concentrator (M-CPC) based on exhaustive algorithm was presented in this paper. The prototype model was established according to the outcome of program calculation, and the concentrated optical path of the designed model was studied by laser verification experiment integrating precision apparatus. The result demonstrated that the intersection position on solar cell surface obtained from calculation outcomes were consistent with the experimental consequences. Five kinds of optimized M-CPCs were designed and compared with S-CPC in optical performance. It is found that M-CPC4 is the optimal structure in this design, whose improvement ratio of average optical efficiency and acceptance angle are 1.375% and 47% respectively compared with S-CPC. Moreover, M-CPC4 could significantly reduce the higher energy peak while ameliorating the non-uniform flux distribution on absorber. This will enable the work system to maintain a relatively stable temperature gradient. The proposed design method could provide technical reference on efficient optical efficiency and structure optimization for M-CPC.

Jurassic Red-Bed sandstone is one of the main types of rock composing unstable slopes on both banks of the Three Gorges Reservoir (TGR) in China. It is vulnerable to tensile strength degradation when exposed to cyclic wet-dry conditions under reservoir operation. Therefore, the law behind this needs to be clarified in order to accurately evaluate the stability of a sandstone slope located in the drawdown area of the TGR. In this paper, Jurassic Red-Bed sandstone specimens from the Majiagou landslide in the TGR area were collected for experiments with cyclic wet-dry procedures. After each wet-dry cycle, efforts were made to implement splitting tests, measure clay mineral contents and ion contents in the soak solution, and observe changes in microstructures. The tensile strength is experimentally demonstrated to be a process of damage accumulation under the integrated actions of water pressure, calcite dissolution, and clay mineral hydration, among which hydration of illite contributes the most to the damage. The loss of the cement material and the cyclic expansion and shrinkage of clay minerals weaken the cementation between grains, leading to the tensile strength degradation.

Porosity is an important parameter for the oil and gas storage, which reflects the geological characteristics of different historical periods. The logging parameters obtained from deep to shallow strata show the stratigraphic sedimentary characteristics in different geological periods, so there is a strong nonlinear mapping relationship between porosity and logging parameters. It is very important to make full use of logging parameters to predict the shale content and porosity of the reservoir for precise reservoir description. Deep neural network technology has strong data structure mining ability and has been applied to shale content prediction in recent years. In fact, the gated recurrent unit (GRU) neural network has further advantage in processing serialized data. Therefore, this study proposes a method to predict porosity by combining multiple logging parameters based on the GRU neural network. Firstly, the correlation measurement method based on Copula function is used to select the logging parameters most relevant to porosity parameters. Then, the GRU neural network is used to identify the nonlinear mapping relationship between logging data and porosity parameters. The application results in an exploration area of the Ordos basin show that this method is superior to multiple regression analysis and recurrent neural network method, which indicates that the GRU neural network is more effective in predicting a series of reservoir parameters such as porosity.

Multimode microwave remote sensors are a new type of radar system that operates in SAR (synthetic aperture radar), scatterometer, altimeter, and spectrometer modes in a time-sharing manner according to the current task scheduled on small satellites. High flexibility through mode switching is the outstanding advantage of this new microwave remote sensor. Two or more small satellites operating in different operation modes can be networked to perform observations synchronously to provide excellent remote sensing performance. This paper focuses on a method to determine the radar parameters of the scatterometer mode since the frequency band and the platform height of this new of kind sensor are determined according to the requirement of the SAR mode, and their values are evidently different from the values of current scatterometers in orbit. The proposed method systematically presents the complete steps and related formulae of the radar parameter design of scatterometers and determines the signal bandwidth by optimization. A system simulation method of the scatterometer mode is further studied to determine the wind field inversion error and thus evaluate the rationality of the parameter design results. In contrast to the existing methods, which directly add noise to the backscatter coefficients, our method simulates the noisy echo of the scatterometer and then retrieves the wind field by estimated backscatter coefficients from the noisy echo. The performed simulation shows that, by using the designed system parameters, the multimode microwave remote sensor obtains wind field inversion accuracy, resolution and swath width comparable to those of the HY-2 satellite and the QuikSCAT satellite.

The Philip-Dunne falling-head infiltration for determining the parameters of soil water movement is a relatively simple procedure, yet the calculation is still complicated. This study develops a si...

In order to bring the theoretical results into harmony or agreement with the reality, this paper copes with the leader-following mean square consensus issue for a class of nonlinear stochastic multi-agent systems with randomly occurring nonlinearities (RONs) and randomly occurring uncertainties (ROUs) under impulse time windows (ITWs). As a majorizing preconfigured mechanism of the windows, the configuration named periodically variable impulse time windows (PVITWs) is put forward. It not only ensures the periodic-based layout of impulse time window (ITW), but also allows the position and width of the window to be arbitrarily adjustable, so that the preset of ITW is more suitable for applications. Based on the Lyapunov stability theory and graph theory, the corresponding sufficient mean square consensus criteria are given. Finally, the feasibility of theoretical analysis is illustrated by numerical simulations.

Various Cu2O nanocrystals (NCs), including cubes exposing {100} crystal planes (c-Cu2O), octahedra exposing {111} crystal planes (o-Cu2O), and rhombic dodecahedra exposing {110} crystal planes (d-C...

The state-of-the-art traffic sign recognition (TSR) algorithms are designed to recognize the textual information of a traffic sign at over 95% accuracy. Even though, they are still not ready for complex roadworks near ramps. In real-world applications, when the vehicles are running on the freeway, they may misdetect the traffic signs for the ramp, which will become inaccurate feedback to the autonomous driving applications and result in unexpected speed reduction. The misdetection problems have drawn minimal attention in recent TSR studies. In this paper, it is proposed that the existing TSR studies should transform from the point-based sign recognition to path-based sign learning. In the proposed pipeline, the confidence of the TSR observations from normal vehicles can be increased by clustering and location adjustment. A supervised learning model is employed to classify the clustered learned signs and complement their path information. Test drives are conducted in 12 European countries to calibrate the models and validate the path information of the learned sign. After model implementation, the path accuracy over 1,000 learned signs can be increased from 75.04% to 89.80%. This study proves the necessity of the path-based TSR studies near freeway ramps and the proposed pipeline demonstrates a good utility and broad applicability for sensor-based autonomous vehicle applications.

Elucidation of the CuOx-CeO2 interactions is of great interest and importance in understanding complex CuOx-CeO2 interfacial catalysis in various reactions. In the present work, we have investigated structures and catalytic activity in CO oxidation of CuOx species on CeO2 rods, cubes and polyhedra predominantly exposing {110}+{100}, {100} and {111} facets by the incipient wetness impregnation method with the lowest Cu loading of 0.025%. The structural evolution of CuOx species was found to depend on both the Cu loading and the CeO2 morphology. As the Cu loading increases, CuOx species are deposited preferentially on the surface defect of CeO2 and then aggregate and grow, accompanied by the formation of isolated Cu ions, CuOx clusters strongly/weakly interacting with the CeO2, highly dispersed CuO nanoparticles, and large CuO nanoparticles. The isolated Cu+ species and CuOx clusters weakly interacting with the CeO2 were observed mainly on the O-terminated CeO2{100} facets. Meanwhile, more Cu(I) species are stabilized during CO reduction processes in CuOx/c-CeO2 catalysts than in CuOx/r-CeO2 and CuOx/p-CeO2 catalysts. The catalytic activities of various CuOx/CeO2 catalysts in CO oxidation vary with both the CuOx species and the CeO2 morphology. These results comprehensively elucidate the CuOx-CeO2 interactions and exemplify their morphology-dependence.

Modulation of the vanadium oxide epitaxial film metal insulator transition process through interfacial strain is a novel approach for controlling the properties of epitaxial vanadium oxide films, improving its scope for device applications. In this work, vanadium oxide films of various thickness were prepared and the effects of strains on the transition temperature were investigated. The vanadium oxide films exhibited compressive or tensile interfacial strain along their c-axis, the transition temperature varied in a range of 310–370 K owing to the effects of the interfacial strains. The tensile strain along the c-axis is correlated with an increase in transition temperature; however, the compressive strain along the c-axis leads to a decrease in transition temperature. The results show that the metal insulator transition process of vanadium oxide thin films can be regulated by interfacial strain. This work shows the feasibility of engineering the phase transition of epitaxial vanadium oxide films or the related devices through strain manipulating, which may be of great importance in practical applications.

Soil contamination by heavy metal is an important problem in agricultural irrigation systems in recent years. To assess the accumulation of, and identify the sources of heavy metals in the Hetao Irrigation District, 195 soil samples from 39 sites of 0-100 cm soil layers were collected and analyzed for heavy metal concentrations of Zn, Cu, Pb, Cr, and Cd. The results indicated that the mean values for these five heavy metals were 107.17, 32.48, 12.31, 53.53, and 0.22 mg kg−1, respectively and insignificantly differed among the soil depths of 0-20, 20-40, 40-60, 60-80 and 80-100 cm (p > 0.05). Zn, Cu, and Cd concentrations were higher than the background levels of the Hetao area, with a moderate accumulation: the mean values of the contamination factor (CF) were 1.9, 1.7 and 1.9, respectively, and the geoaccumulation index (Igeo) was > 0 for these three elements; Pb and Cr concentrations were lower than or close to the background levels, with CF < 1 and Igeo < 0, indicating origination from a natural source. Values of the monomial potential ecological risk index (Eri) for Zn, Cu, Pb, and Cr were much lower. However, the mean value of Eri for Cd was 55.73, implying a moderate risk in the soils. The ecological risk (RI) of the five heavy metals was much lower, with the mean content of 77.18, declining from the south to the north of the district. In our study, the soils were previously contaminated with Zn, Cu, and Cd, and the results of principal component analysis (PCA) revealed that two different anthropogenic sources were indicated (PC2 and PC3). The enrichment of Cd and, partially, of Cu, heavier in PC2, was related to agricultural activities, such as excessive application of commercial fertilizers, pesticides, and livestock manures among others. Zn and partly Cu, closely associated with PC3, may have originated from irrigation water derived from the Yellow River. In the future, development of agriculture should pay more attention to the application of fertilizers and pesticides and the quality of irrigation water in the irrigation district.

Dark-field microscopy (DFM) based on localized surface plasmon resonance (LSPR) was used for observation of experimental phenomena, which is a hopeful nondamaging and non-photobleaching biological imaging technique. In this strategy, plasma nanoaggregates with stronger scattering efficiency were formed in the presence of the target, causing a "turn-on" phenomenon, when asymmetry modified AuNPs were introduced as probes with zero LSPR background. First, Au1-N3 probe and Au2-C≡C probe were designed for the cycloaddition between azide and alkyne to form AuNP dimers under catalytic action by Cu+, which was obtained from the reduction of Cu2+ by sodium ascorbate. The two kinds of probes were successfully used for the detection of Cu2+ in rat serum. Then, to apply this concept to protein on cells, DNA and antibody were modified on the probes. DNA1/Au1-N3 probe and anti-HER2/Au2-C≡C probe were proposed for HER2 protein DFM on cells. By designing an aptamer sequence in primer, the rolling circle amplification (RCA) was introduced in HER2 DFM on cells, and the image signal was much brighter than that from no-RCA. The unique design made it easier to discriminate the target signal from background noise in cell DFM. This method might be used in the fields of molecular diagnostics and cell imaging.

This paper probes into the leader-following mean square consensus problem of stochastic multi-agent systems with randomly occurring uncertainties (ROUs) and randomly occurring nonlinearities (RONs) under impulse time windows (ITWs). A new concept named average left endpoint interval (ALEI) related to ITWs is proposed, which is inspired by the average impulsive interval. Based on ALEI and Lyapunov stability theory, a unified mean square consensus criterion for both stabilizing and interference impulses is attained. The introduction of ALEI allows for a larger upper bound of left endpoint interval and smaller lower bound of left endpoint interval, which makes the preset of ITWs more flexible and less conservative. The validity of the theoretical results is verified by the numerical simulation.

Epithelial-mesenchymal transition (EMT) is critically involved in a variety of biological processes. Electrochemical sensing offers potential to develop more effective technology for EMT detection. In this study, by using the unique performance of quantum dot (QD)-nanocomposite materials, we establish an electrochemical biosensor that can specifically detect the change of E-cadherin and analyze different stages of EMT. The signal for EMT is largely magnified due to the transmission of molecular information to the electronic device. In addition, differential pulse voltammetry reveals that the response of the electrochemical signals is rapid and sensitive, due to the synergistic effect of QDs and carbon nanotube-gold nanoparticles. Our study thus suggests that electrochemical sensing is an effective technology for detecting EMT and may have broad applications in analyzing various cell type transitions., Epithelial-mesenchymal transition (EMT) plays a key role in embryonic development, wound healing and cancer. Here the authors develop an electrochemical sensor to detect EMT using E-cadherin antibody-quantum dot conjugates and a carbon nanotube-gold nanoparticle-modified electrode as a detection platform.

The Ni-based Hastelloy X (HX) superalloy is widely used in aero-engine components because of its exceptional high-temperature strength and oxidation resistance. Given the complex structure of such parts, additive manufacturing (AM) technologies such as laser powder bed fusion (LPBF) are employed to manufacture these components. HX alloy suffers from crack susceptibility during the LPBF process, however. In this paper, this issue was addressed by adding 2 wt% submicrometer TiB2 powder through a high-speed mixing process. Both the low-angle grain boundaries (LAGBs) and high-angle grain boundaries (HAGBs) were noted to have increased in the as-fabricated HX-2 wt.% TiB2 composite, with an average grain size reduction from 14 μm to 8.69 μm. In addition, compared with pure HX, the hardness of the HX-2 wt.% TiB2 composite was increased by 43.4% and 50.8% at room-temperature and high-temperature (850 °C) conditions, respectively. This indicates that the added TiB2 reinforcement was more influential to the mechanical property enhancement under high-temperature compared to the room temperature conditions. The composite sample also showed a 28% increase in yield strength while the ductility was not found to be sacrificed compared to the as-fabricated pure HX, indicating that an addition of specific ceramic particles with suitable content may offer a new method for manufacturing crack-free high-strength and high-toughness HX alloy through the AM process. These findings also provide a reference for improving the properties of other advanced materials made by the LPBF process.

Electromagnetic field inverse calculation plays a crucial role in solving the problem arising from the design and non-destructive testing of electromagnetic devices in engineering. In this study, an optimisation algorithm for electric field inverse calculation is proposed, which enables non-destructive detection of voltage on overhead transmission lines, enhances the robustness of the algorithm and improves the accuracy of calculation. Firstly, 2D and 3D calculation models of electric field are established. A multimedium calculation model with the operating environment of transmission lines considered is proposed. Based on the multimedium calculation method, the calculation environment is categorised into soil, vegetation, geology, and other media, and the correctness of the optimisation method is verified by the finite-element method-based model. Secondly, in order to eliminate the measurement noise and electric field distortion to the electric field measurement data, a modified model based on Kalman filter is constructed. Both multimedium calculation method and Kalman filter are applied to the inverse calculation of electric field as an optimisation electric field inverse solving algorithm. Finally, the inverse optimisation method is applied to 220 kV transmission lines and practical 500 kV ultra-high voltage transmission lines, respectively, to improve the accuracy and robustness of calculation.

In this paper, undoped and Cr-doped VO2 thin films were fabricated and deposited onto Al2O3 substrates using a sol-gel method. Then, the effects of Cr-doping on the thermochromic, and optical properties of the thin films were investigated. Doping with Cr ions gradually increased the metal-insulator transition (MIT) temperature of the films, while the luminous transmittance (Tlum) and the sol modulation efficiency (ΔTsol) gradually decreased. Additionally, Pt/VO2/ITO devices and Cr-doped VO2 devices were prepared to study their threshold switching (TS) properties. For devices fabricated with Cr-doped VO2 films, both the threshold voltage (Vth+) and the OFF-state current decreased as the amount of Cr doping increased. In contrast, the ON/OFF ratio increased from 104 to 105. These results provide insight into the potential for using VO2 in thermochromic, optical, and TS applications.

The opening characteristics of a 3-D power operated pressure relief valve were studied experimentally and numerically. The experimental results were used to study the mechanism controlling the valve opening time. The CFD simulations used the trimmed volume mesh deformation technique to study the full transient opening dynamic characteristics of the valve. The pressure and velocity fields were obtained including the small scale flow features. The CFD results were used to analyze the upper surface average pressure, surface velocity, resultant force and displacement of the disc during opening. The inlet and outlet mass flow of the valve was in a stable state when the valve opening time was 1.43 s. Moreover, the influence of the size structural parameters on the valve opening time was studied. The simulation results compare well with test data including the shock wave during the valve opening. The results show that the geometric factors affecting the valve opening time can be modified to reduce the valve opening time. It shows that the area of the region between the relief hole (orifice D) connected to the solenoid valve and the vertical tube has the greatest influence on the valve opening time. Due to the upward movement and misalignment of the disc, the valve opening time is delayed during the operation of pressure relief valves. The conclusions of this paper provide guidance for the optimal design of safety valves.

Gregory D. Abowd shows a new vision of computer framework - collective computing. In this framework, kinds of remote computing devices, including even people who are regarded as a kind of computing device, are connected with each other into a group to complete a complex work. Therefore, the various computing devices with the different computing capacities can be fully used in different tasks. However, most of the relevant researches focus on improving infrastructure to address specific functions, the heterogeneous tasks performed in a common architecture and the large-scale integration are not paid enough attention. This paper presents a collective computing architecture for supporting concurrent multi-sourced heterogeneous tasks. The whole architecture is layered to provide different functions and obtain extensibility, loads balance, centralized dispatch and low delay communication. The extendible collective computing engine is used for analysing and allocating heterogeneous tasks, and the distributed device management controls heterogeneous computing devices. This architecture provides a common infrastructure for processing heterogeneous tasks by heterogeneous devices which dose not only design for some specialized systems or functions. At last, we implement a prototype system by this architecture for proving that the architecture can perform multi-sourced heterogeneous tasks well.

Simultaneous removal of the antibiotics and heavy metals has attracted increasing attention since these contaminants are frequently detected in the aquatic environment. In this study, highly active nano-Mg(OH)2 was synthesized and firstly applied in catalytic ozonation system for simultaneous removal of metronidazole (MNZ) and heavy metal ions (Cu2+ and Zn2+). The results showed that the synthesized Mg(OH)2 nanoparticles exhibited high efficiencies of removing both MNZ and heavy metal ions (Cu2+ and Zn2+) in the catalytic ozonation process. Surprisingly, the removal efficiency of MNZ in the catalytic ozonation system with nano-Mg(OH)2 catalyst was improved in the presence of Cu2+ and Zn2+. Some parameters such as catalyst dosage, initial concentration of MNZ, initial concentration of heavy metal and reaction temperature could affect the simultaneous removal of MNZ and heavy metal ions (Cu2+ and Zn2+). This study provides an innovative and effective method for the simultaneous removal of antibiotics and heavy metals from the aquatic environment.

FePt3(disordered)/FePt3(ordered) bilayers are ideal for studying exchange bias in FM/AFM heterostructures. The effects of phase competition between the two different antiferromagnetic phases in the bilayer system needs clarification to understand exchange bias in these bilayers. This is accomplished by preparing films with different crystallographic orientations. It is found that exchange bias fields in single layer films are dependent on their order parameters, whilst the exchange bias fields of bilayer films are determined by their film orientation. Bilayer films with a (001) orientation exhibit the largest exchange bias field at 20 K, whose value diminishes as the order parameter of the FePt3 layer decreases. This phenomenon can be explained by the formation of the Q2 phase in the ordered FePt3 layer at low temperatures. First principles calculations suggest that disorder defects in the interface and top FM layer play an important role in inducing a Q2 phase in the AFM layer. Therefore, bilayer films with a (001) orientation can undergo temperature dependent phase changes, showing that they are a good model system for studying exchange bias in FM/AFM heterostructures.

This study developed prestressed high-strength concrete (PHC) piles reinforced with high-strength materials (glass fiber-reinforced polymer (GFRP) bars) for flexural performance enhancement. Flexur...

Au nanoparticles with different loadings were prepared on anatase TiO2 nanocrystals with various morphologies predominantly exposing {001} facets (denoted as TiO2{001}), {100} facets (denoted as TiO2{100}) and {101} facets (denoted as TiO2{001}) by the deposition–precipitation method. Sizes, structures, and catalytic activity in low-temperature CO oxidation of the resulting Au/TiO2 catalysts were comprehensively characterized. Nucleation, growth, and agglomeration of Au particles on TiO2 supports were observed to depend on TiO2 morphologies due to the morphology-dependent defect structures of TiO2 nanocrystals and subsequent Au–TiO2 interactions. Au particles mainly homogeneously nucleate and grow on these three TiO2 nanocrystals with Au loadings of 0.2–1%. With the increase in Au loadings to 2 and 5%, Au particles mainly agglomerate on TiO2{001}, mainly homogeneously nucleate and grow on TiO2{100}, and both nucleate and grow and slightly agglomerate on TiO2{101}. The electronic effect of supported Au par...

To explore feasibility of AISI 630 steel applied to slipper/swashplate pair of a water hydraulic pump. Frictional corrosion experiment simulating slipper/swashplate pair operation was systematically conducted under three different lubricating conditions, and the influence of lubricating medium and solution aging on corrosion wear of AISI 630 steel and indirect corrosion wear of its dual PEEK surface were evaluated by means of scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical corrosion test analysis. It was shown that synergistic effect of corrosion and wear played an important role on wear of AISI 630 steel and occupied up to 25% of its total wear loss. Solution aging of AISI 630 steel could help to decrease wear rate of its dual PEEK surface in freshwater, but would significantly increase friction coefficient and wear rate of AISI 630 in seawater and aggravate the wear and indirect corrosion wear of its dual PEEK surface. Therefore, for the water hydraulic slipper/swashplate pair, it is suggested that when taking service in freshwater, solution aging of AISI 630 steel can be considered to alleviate wear of its dual PEEK surface, but when taking service in seawater, solution aging is not recommended, and the original AISI 630 steel is more conducive to obtain preferable friction and wear performance.

Crop residue decomposition has an important impact on soil organic carbon (SOC) sequestration and CO2 emission. Residue quality and management strategies are two important factors regulating decomposition process and SOC mineralization and greenhouse gas emission. In this study, a microcosm experiment in field condition was conducted on a silty loam (a Black soil) in Northeast China to investigate stover decomposition and soil CO2 emission characteristics as influenced by different crop cultivars and stover field incorporation methods. Stover from two popular maize cultivars Xianyu335 (XY) and Liangyu99 (LY) were applied in two modes (soil surface application vs soil incorporation) at a rate of 11 t ha−1, and CO2 efflux was monitored during the decomposition duration of 144 days. The structural transformation of carbon functional groups in maize stover were evaluated using solid state 13C-CPMAS NMR and elemental analysis techniques. Results showed that up to 71.7%∼86.9% (weight basis) of C and N in soil-incorporated stover was decomposed during the study period, which was significantly greater than the losses (32.8%∼55.3%) of C or N from the surface-applied stover for both maize cultivars; decomposition rates of main C functional groups were significantly higher in soil incorporation (71.1%∼88.8%) than in surface application (20.9%∼60.2%) systems. The concentrations of SOC, total N, available N, and microbial biomass C and N in soil were also higher with stover incorporation than surface application. Stover incorporation resulted in a notably lower CO2 emission rate and accumulative CO2 efflux (53.9–55.4 mol m−2) during the stover decomposition compared with surface application (57.4–67.0 mol m−2). Between the two maize cultivars, the LY stover showed a higher decomposition rate and greater capacity for SOC sequestration when incorporated into soil. The LY stover induced higher (16.8%) CO2 emission than XY when applied on soil surface, but no significant difference was found between the two cultivars when incorporated into soil. The results suggested that cultivar selection and stover management strategies have great potential in reducing soil CO2 emission while improving soil biochemical properties. Incorporating the LY stover into soil rather than surface mulching could enhance SOC sequestration and reduce CO2 emission.

Unravelling the adsorption mechanism is crucial in designing highly efficient adsorbent for removing heavy-metal ions from aqueous solution. In this paper, a biomass-derived hierarchically porous carbon (HPC) with oxygen- and nitrogen-containing functional groups has been adopted to investigate the adsorption equilibrium and mechanism towards heavy-metal ions (Cu (II), Zn (II), Pb (II), Cd (II), and Cr (III)). It indicates that the adsorption of heavy-metal ions on HPC all fit well with the Langmuir model, but present different adsorption capacity at the same condition. In addition, thermodynamic parameters including Gibbs free energy change and Enthalpy change of these adsorption processes also resemble the variation of the adsorption capacity, implying that the intrinsic characteristics of heavy-metal ions play critical role in the adsorption. Through analyzing the chemical state of the adsorbed heavy-metal ions on HPC, the first hydrolysis constant that is correlated with the hydrolyzing capability of the metal ions, are found to be responsible for the adsorption disparity of HPC towards the five heavy-metal ions since it decides the contact ratio of hydrolyzed heavy-metal ions with HPCs in aqueous solution. Therefore, this work is meaningful in providing a clear and detail insight into the adsorption disparity mechanism of porous carbon towards the removal of heavy-metal ions.

This study investigated the distribution, sources, and potential risks of polycyclic aromatic hydrocarbons (PAHs) in coastal waters along over 18,000 km of coastline in China. Concentrations of PAH...

This paper discusses the finite-time and the fixed-time consensus of nonlinear stochastic multi-agent systems (NSMSs) with randomly occurring uncertainties (ROUs) and randomly occurring nonlinearities (RONs) in a leader-following framework. Nonlinear control and impulsive pinning control protocols are designed to guarantee that follower agents realize consensus with the leader agent in finite time(fixed time). Based on the finite-time and fixed-time consensus theory, stochastic analysis technique, comparison system theory and algebra graph theory, some sufficient conditions are proposed to guarantee the finite-time and fixed-time consensus of systems. Then, the setting times of finite-time consensus and fixed-time consensus are estimated. Finally, two simulation examples are presented to illustrate the correctness of our conclusions.

1-Methylcyclopropene (1-MCP) is an important gaseous plant growth regulator. For its application as a gaseous pesticide, the plants with 1-MCP α-cyclodextrin microcapsule granules need to be enclosed in a sealed chamber. To provide a new spray formulation of 1-MCP for open environment application, herein, a novel 1-MCP microcapsule oil dispersion (1-MCP/MCOD) was prepared and characterized. It was found that 1-MCP could stay at higher concentrations for more than 36 hours during the controlled release experiment, and the SEM experiment showed good deposition of the 1-MCP/MCOD spray solution. In addition, the apple harvest application experiments showed that 1-MCP/MCOD could effectively prevent fruit drop at 3 μL L−1 in an open environment. These results not only supply a new 1-MCP/MCOD kind of formulation for the flexible application of the 1-MCP gas in an open environment, but also show that this microcapsule oil dispersion formulation has significant potential in gaseous pesticide applications.

Various Ag/Cu2O nanocomposites were prepared via the galvanic replacement reaction involving AgNO3 reacting respectively with uniform Cu2O cubes and octahedra. Their compositions and structures were comprehensively characterized microscopically and spectroscopically. The results reveal that the crystal plane of employed Cu2O solid templates determines the compositions and structures of the resulting Ag/Cu2O nanocomposites. A smooth surface mixed with nanoneedles or nanosheets of Ag/c-Cu2O structures was fabricated on Cu2O cubes while flocculent Ag/o-Cu2O structures were fabricated on Cu2O octahedra. The catalytic performance of Ag/Cu2O nanocomposites were evaluated in CO oxidation with excess O2. In situ surface restructuring occurs on various Ag/Cu2O nanocomposites to form Ag–CuO/Cu2O nanocomposites. The catalytic activity of the resulting Ag–CuO/Cu2O nanocomposites depends on the structures of CuO and Ag that are affected by the original crystal plane of Cu2O solid templates and the Ag loading. These results broaden the crystal-plane effect of Cu2O nanocrystals as solid templates for synthesis of multicomponent nanocomposites via liquid–solid interfacial reactions.

The electrocatalytic nitrogen reduction reaction (NRR) under ambient conditions is regarded as a promising substitute approach to the Haber–Bosch process for artificial N2 fixation to NH3. In this communication, we constructed well-defined one-dimensional MnO nanocrystals encapsulated in carbon nanofibers (MnO–CNF) via an electrospinning method. MnO–CNF behaves as an excellent non-noble-metal NRR electrocatalyst for NH3 synthesis with a faradaic efficiency of 1.52% in 0.1 M Na2SO4 solution under ambient conditions. Remarkably, it attains a high NH3 formation rate of 35.9 μg h−1 mgcat−1 and also shows excellent durability during electrolysis and recycling tests.

Spent pot-lining from aluminum electrolysis and coal gangue are toxic and hazardous solid wastes with high recovery value and contents of valuable elements, such as carbon, silicon, aluminum and fluorine. Thus, harmless treatment and recycling of these materials are of considerable importance. For extracting valuable components, Spent pot-lining and coal gangue were co-treated by hydrothermal acid-leaching method in this study. Effect of adding spent pot-lining on impurities leaching rate of coal gangue was systematically studied, and results indicated that fluoride in spent pot-lining positively affected the decomposition of coal gangue. Moreover, effects of leaching temperature, initial acid concentration, time, and particle size, on the extraction efficiency of aluminum were investigated comprehensively. Optimum parameters obtained by single-factor test included reaction temperature of 200 °C, initial hydrochloric acid concentration of 10 mol/L, time of 10 h, liquid–solid ratio of 10:1, and particle size below 200 mesh. Under these conditions, leaching rate of aluminum reached to 92.47%. Acid-leaching residue was used in the preparation of silicon carbide powder by carbothermal reduction, and silicon carbide powder with small size (D50, the median diameter, of 18.15 μm) was obtained by firing the acid-leaching residue at temperature of 1600 °C for 5 h. This study provides an inspiring approach for recovering and reusing spent pot-lining and coal gangue.

Nickel-based superalloys such as Hastelloy X (HX) are widely used in gas turbine engines for their exceptional oxidation resistance and high-temperature strength. The addition of ceramic reinforcement further enhances these superalloys’ mechanical performance and high-temperature properties. For this reason, this paper investigates the microstructure and mechanical property of laser powder bed fusion (LPBF) additively manufactured HX–1 wt% WC (tungsten carbide) composite specimens. The results demonstrate that the LPBF-fabricated composite was observed to have several pores and microcracks, whilst only pores were detected in the as-fabricated pure HX. Compared to the fabricated pure HX, the tensile yield strength of such HX composite parts was increased by 13% without undue sacrifices to ductility, suggesting that the very limited number of microcracks were not sufficient to degrade the mechanical performance. The significantly increased dislocations were considered to be the primary contributor for the mechanical performance enhancement in the LPBF-fabricated composite material. The findings offer a promising pathway to employ LPBF process to fabricate advanced microcrack-free composites with high-strength through a careful selection of ceramic reinforcement materials.

This paper introduces the composition and function of the seeker servo system, and establishes the mathematical models of DC torque motor, gyro, resolver and power amplifier. In order to solve the problem of poor dynamic immunity of single closed-loop correction system, a speed negative feedback double closed-loop correction system is designed and verified by simulation.

In this study, we report the observation of ultralow Gilbert damping in epitaxial ${\mathrm{CrO}}_{2}$ films. The dynamic properties of (100)- and (110)-oriented ${\mathrm{CrO}}_{2}$ epitaxial films grown on ${\mathrm{TiO}}_{2}$ substrates were studied using ferromagnetic resonance measurements based on a resonant cavity and a coplanar waveguide in a large frequency range. The Lande $g$ factor was found to be 1.98, and it was independent of film orientation and thickness. The effective damping constant rapidly increased with film thickness when the film thickness was smaller than 50 nm, which might be attributed to magnon scattering. Extremely low damping was observed in the (110)-oriented ${\mathrm{CrO}}_{2}$ film with a thickness of 364 nm, and the damping constant was obtained as $(6.2\ifmmode\pm\else\textpm\fi{}0.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. This value is about half an order of magnitude lower than that of ultralow-damping CoFe systems $[(1.3\text{--}2.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}]$ and is comparable with the lowest value observed recently in some Heusler alloy systems. The extremely low damping behavior in the ${\mathrm{CrO}}_{2}$ system is strongly correlated with its half-metallic nature.

High air pollutant emissions in China have become serious environmental issues threatening public health. While spatial heterogeneity plays an important role in environmental regulation in China, it is necessary to analyze the spatial heterogeneity influences of air pollution control policies and informal environmental regulation on air pollutant emissions in China. Based on the quantification of air pollution control policies, this paper incorporates the central government&rsquo, s policy formulation and local government&rsquo, s policy implementation into the intensity of air pollution control policy. This paper uses the panel data of China&rsquo, s 30 provinces to examine the spatial impact of air pollution control policy and informal environmental regulation on air pollutant emissions. The results show that (a) air pollutant emissions represented by soot and dust emission intensity has a significant positive spatial spillover effect, (b) air pollution control policy and informal environmental regulation play significant inhibitory roles in air pollutant emissions, (c) informal environmental regulation has a negative moderating effect on the negative relationship between air pollution control policy and air pollutant emissions. Other implications for environmental management have also been discussed.

Surface oxidation of SnSe sharply reduces its thermoelectric properties though the bulk single-crystalline materials of SnSe claim the record high zT values. Investigation on the oxidation behaviors of SnSe together with the subsequent phase transition and element migration is fundamentally important to maintaining the ultrahigh zT values, with a potential for further improvement. In this work, we disclose the dynamic epitaxial crystallization of SnSe2 on the amorphous surface of partially oxidized SnSe crystals and the corresponding atomistic mechanisms via transmission electron microscopy (TEM). It is revealed that the thermally annealed amorphous surface crystallized to SnO2 and SnSe2 in the outermost and secondary layers, respectively, forming distinctive SnSe/SnSe2/SnO2 multilayer heterostructures with specific orientation relationships between the two selenides. By means of in situ scanning TEM (STEM), the dynamic epitaxial crystallization process of SnSe2 was revealed when the oxidized SnSe surface was subjected to electron beam irradiation. Through the atomic-scale characterization and modeling analysis, we find that the exposed dangling Se diatoms on the SnSe surface serve as nucleation sites for lateral epitaxial crystallization of SnSe2. The same valence and similar coordination configuration of Se atoms in these two phases are supposed to facilitate the sharing of Se atoms, with lattice distortions in the SnSe2/SnSe interface. These findings are valuable for understanding the surface oxidation behavior of SnSe and revealing the interface structures of SnSe2/SnSe heterojunctions and also offering new routes for SnSe-related multilayer or heterostructure system design.

The W1Mo1-NG dual-atom catalyst enables Pt-like activity and ultrahigh stability for hydrogen evolution reaction., Single-atom catalysts (SACs) maximize the utility efficiency of metal atoms and offer great potential for hydrogen evolution reaction (HER). Bimetal atom catalysts are an appealing strategy in virtue of the synergistic interaction of neighboring metal atoms, which can further improve the intrinsic HER activity beyond SACs. However, the rational design of these systems remains conceptually challenging and requires in-depth research both experimentally and theoretically. Here, we develop a dual-atom catalyst (DAC) consisting of O-coordinated W-Mo heterodimer embedded in N-doped graphene (W1Mo1-NG), which is synthesized by controllable self-assembly and nitridation processes. In W1Mo1-NG, the O-bridged W-Mo atoms are anchored in NG vacancies through oxygen atoms with W─O─Mo─O─C configuration, resulting in stable and finely distribution. The W1Mo1-NG DAC enables Pt-like activity and ultrahigh stability for HER in pH-universal electrolyte. The electron delocalization of W─O─Mo─O─C configuration provides optimal adsorption strength of H and boosts the HER kinetics, thereby notably promoting the intrinsic activity.

In this paper, we present a novel 3D object detection framework for locating 3D bounding boxes of the target in autonomous driving scenes. Our proposed framework consists of two novel modules, which are twofold proposal fusion module and the RoI deep fusion module. In the former module, we utilized the 3D voxel Sparse Convolution Neural Network (CNN) and PointNet-like network to coarse generate the voxel-based and point-based proposals, where these proposals contain voxel-dense and point-wise features under the raw point cloud. Twofold proposal fusion module integrated those proposals and extended the proposal generalization, thereby dramatically improve the proposals’ recall rate in the first stage for further utilizing in the proposals refinement stage. Given the coarse integrated 3D proposals produced by the twofold proposal module, the RoI deep fusion module is proposed to abstract and aggregate the multi-scale voxel-based feature and the point-wise feature through voxel-aware pooling layer and point-aware pooling layer, respectively. Follow by that, the specific features on the different proposals are integrated via the proposals-aware fusion layer to further enrich the feature dimensionality and utilize the high-quality proposals for the proposals refinement stage to reinforce the prediction of the target bounding boxes. We conduct the experiments on KITTI dataset and evaluate our method on 3D object detection task. Our method achieved 76.79 mAP in moderate difficulty and outperformed many influential object detection models on the KITTI benchmark leaderboard.

The planarian flatworm is an ideal model to study the regeneration due to its robust regenerative ability. A variety of cellular response activities have been reported to be involved in the regeneration process, including the mitogen-activated protein kinase (MAPK) signaling. However, the mechanism of MAPK pathway in regenerative responses is still unclear. In this study, we employed the planarian, Dugesia japonica, as the model to investigate the function of MAP-extracellular signal-regulated kinase (MEK), an important component of MAPK signaling pathway, in the regeneration process. We found that MEK was required for the missing tissue response after several amputation and subsequent regeneration. MEK not only affected the size of blastema in the early stage of regeneration by regulating stem cell proliferation, but also determined the planarian's regeneration through balancing cell proliferation and apoptosis. In addition, the activation of Wnt pathway partially rescued regenerative defects induced by inhibition of MEK. Taken together, our results highlight a crucial role of MEK signaling in the planarian regeneration.

Qiandao Lake is located in the northern edge of subtropics, and its water body is thermally stratified in summer. It is of great scientific significance to study the vertical physical and chemical indexes and phytoplankton characteristics of the Qiandao Lake to reveal the aquatic ecosystem structure of the thermally stratified lake. Conventional observation uses in-situ profile instruments, which is time consuming and labor intensive. In recent years, lidar has shown increasing oceanic applications; however, it has not yet been extensively applied in inland water. There are no studies using lidar for detecting subsurface plankton layer in Qiandao Lake. In this study, we investigated the applicability of this technology for identifying subsurface plankton layer. A simple and fast phytoplankton layer detection method was introduced. The lidar-detected layer was found to well correspond with that of the in-situ measured subsurface chlorophyll maximum layer (SCML) and phycocyanin maximum layer. Primary results show that lidar and our detection method are effective for subsurface phytoplankton layer detection. They can serve as a good monitoring tool for studying inland water stratification.

Two-dimensional (2D) magnetic materials with high perpendicular anisotropy, such as Fe3GeTe2, have the potential to build spintronic devices with better performance and lower power consumption. Here, we examine microwave emissions in Fe3GeTe2/Pt spin Hall nano-oscillators with different numbers of layers of Fe3GeTe2 using micromagnetic simulations. We predict that auto-oscillation with a frequency of >30 GHz can be driven by spin-orbit torque (SOT) and the frequency is tunable with current. Observing the dynamic behaviors of magnetization dynamic reveals that non-localized spin-wave propagates in Fe3GeTe2 with a spatially varied wavelength due to Joule heat and forms certain special bubble-like magnetic structure. Our results indicate SHNOs comprising a 2D magnetic material has the potential to develop future spintronic oscillator with low power consumption and high performance.

ZrO2 films were deposited on a 304 stainless steel surface using the sol-gel method. The wear behaviour of the sample coated with nano-ZrO2 films were tested by tribometry in distilled water, a 5% NaCl solution and a dry environment at room temperature. Simultaneously, a study on the tribological properties of the ZrO2 films was conducted. The results indicated that the average friction coefficient decreased with the increase of the applied load under dry friction and friction in the 5% NaCl solution. Furthermore, the existence of ZrO2 films, distilled water and 5% NaCl solution reduced the average friction coefficients of the sample coated with nano-ZrO2 films. Moreover, adhesive wear and oxidation wear were the primary wear mechanisms of the matrix and coated specimen under dry friction. Nevertheless, for the friction of the coated sample in the distilled water and the NaCl solution, adhesive wear and abrasive wear occurred primarily during friction. Corrosion wear also occurred, and the cutting traces were relatively tidy in the 5% NaCl solution.

Aiming at the problem of host load forecasting in mobile cloud computing, the Long Short Term Memory networks (LSTM) is introduced, which is suitable for the complex and long-time series data of the cloud environment and a load forecasting algorithm based on Glowworm Swarm Optimization LSTM neural network is proposed. Specifically, we build a mobile cloud load forecasting model using LSTM neural network, and the Glowworm Swarm Optimization Algorithm (GSO) is used to search for the optimal LSTM parameters based on the research and analysis of host load data in the mobile cloud computing data center. Finally, the simulation experiments are implemented and similar prediction algorithms are compared. The experimental results show that the prediction algorithms proposed in this paper are superior to similar prediction algorithms in prediction accuracy.

Disintegration behavior of purple mudstone in the drawdown area of the Three Gorges Reservoir (TGR) in China, as a result of exposure to cyclic wetting and drying (WD) conditions, promotes bank slope instability during reservoir operation. To better understand the disintegration behavior of the mudstone in the drawdown area during reservoir operation, 63 strongly weathered purple mudstone (SWPM) samples from the Triassic Badong group (T2b) in Badong County of the TGR area were collected for laboratory-based cyclic WD experiments. After each WD cycle, measurements of the grain size distribution curve, the clay minerals contents and the ion (K+, Na+, Ca2+ and Mg2+) content in the soak solution, tests of water absorption, and observations of microstructure were conducted on the SWPM samples. Grain size distribution curves show that the SWPM samples disintegrate during WD cycles. The ion contents in the soak solutions and clay mineral contents in the SWPM samples indicate that the clay minerals in the surficial zone of the samples run into the soak solution by hydration between deionised water and clay minerals when each wetting procedure is performed, which weakens the cement between the grains and promotes the disintegration of the SWPM samples. The microstructural observations and water absorption variations exhibit increases in pores and cracks in the surficial zone of the SWPM mudstone sample, resulting from clay mineral content losses during the wetting procedure and shrinking in volume of the SWPM sample under the drying procedure in each WD cycle. The decrease in clay mineral content and increases in pores and cracks in the surficial zone of the SWPM sample are the main reasons for the disintegrations of the SWPM samples undergoing WD cycles, with the disintegration proceeding in the form of a peeling onion.

We present a numerical analysis on injection-induced crack propagation and coalescence in brittle rock. The DEM network coupling model in PFC is modified to capture the evolution of fracture geometry. An improved fluid flow model for fractured porous media is proposed and coupled with a bond-based DEM model to simulate the interactions among cracks induced by injecting fluid in two nearby flaws at identical injection rates. The material parameters are calibrated based on the macro-properties of Lac du Bonnet granite and KGD solution. A grain-based model, which generates larger grains from assembles of particles bonded together, is calibrated to identify the microscopic mechanical and hydraulic parameters of Lac du Bonnet granite such that the DEM model yields a ratio between the compressive and tensile strength consistent with experiments. The simulations of fluid injection reveal that the initial flaw direction plays a crucial role in crack interaction and coalescence pattern. When two initial flaws are aligned, cracks generally propagate faster. Some geometrical measures from graph theory are used to analyze the geometry and connectivity of the crack network. The results reveal that initial flaws in the same direction may lead to a well-connected crack network with higher global efficiency.