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In this paper, the long-lasting impact of the winter North Atlantic Oscillation (NAO) on Arctic sea ice is investigated using reanalysis data, with focus on the Barents–Kara (BK) sea where the air-sea-ice response is closely associated with the interdecadal shift in the northern action center of the NAO. A significant negative correlation between the winter NAO and the late autumn BK sea ice has been dominant since the early 2000s, which is in sharp contrast to the extremely weak correlation before the late 20th century. When the northern center of the NAO retreats westward, a prevailing low-level southerly wind anomaly creates significant positive air temperature anomalies over the BK sea, and the induced ocean current strengthens the northward transport of warm sea water, resulting in a positive BK upper-layer ocean temperature anomaly and a negative sea ice anomaly until early spring. Entering summer, the preexisting less-than-normal sea ice causes the amount of solar shortwave radiation absorbed by the upper-layer sea water to significantly increase and thereby continues to warm up the upper layer of sea water and reduce the sea ice. The warmed sea water enables the negative sea ice anomaly to last until late autumn owing to its relatively large specific heat capacity. Thus, the NAO in the previous winter exerts a long-lasting impact on the BK sea ice.

Three-dimensional (3D) graphene with a high specific surface area and excellent electrical conductivity holds extraordinary potential for molecular gas sensing. Gas molecules adsorbed onto graphene serve as electron donors, leading to an increase in conductivity. However, several challenges remain for 3D graphene-based gas sensors, such as slow response and long recovery time. Therefore, research interest remains in the promotion of the sensitivity of molecular gas detection. In this study, we fabricate oxygen plasma-treated 3D graphene for the high-performance gas sensing of formaldehyde. We synthesize large-area, high-quality, 3D graphene over Ni foam by chemical vapor deposition and obtain freestanding 3D graphene foam after Ni etching. We compare three types of strategies—non-treatment, oxygen plasma, and etching in HNO3 solution—for the posttreatment of 3D graphene. Eventually, the strategy for oxygen plasma-treated 3D graphene exceeds expectations, which may highlight the general gas sensing based on chemiresistors.

Developing highly efficient and stable electrocatalysts for oxygen evolution reaction is of significant importance for applications in energy conversion and storage. Modulation of electronic structure of catalysts is critical for improving the performance of the resulting electrodes. Here, we report a facile way to engineer the electronic structure of Ni3FeS by coating a thin polyaniline (PANI) layer for improving electrocatalytic activity for overall water splitting. Experimental investigations unveil that the strong electronic interactions between the lone electron pairs of nitrogen in PANI and d orbitals of iron, nickel in Ni3FeS result in an electron-rich structure of Ni and Fe, and consequently optimize the adsorption and desorption processes to promote the OER activity. Remarkably, the resulting PANI/Ni3FeS electrode exhibited much enhanced OER performance with a low overpotential of 143 mV at a current density of 10 mA·cm−2 and good stability. Promisingly, coupled with the reported MoNi4/MoO2 electrode, the two-electrode electrolyzer achieved a current density of 10 mA·cm−2 with a relatively low potential of 1.55 V, and can generate oxygen and hydrogen bubbles steadily driven by a commercial dry battery, endowed the composite electrocatalyst with high potential for practical applications.

In the biological locomotion, the ambit pressure is of particular importance to use as a means of propulsion. The multiple vortex rings have been proved to generate additional thrust by interaction, but the mechanism of this thrust enhancement is still unknown. This study examines the effect of ambit pressure on formation enhancement in interacting dual vortex rings. The vortex rings, which have the same formation time, are successively generated in a piston-cylinder apparatus. The finite-time Lyapunov exponent (FTLE) visualizes the flow fields as an indication of Lagrangian coherent structures (LCSs), and the pressure field is calculated based on the digital particle image velocity (DPIV). We extract the back pressure of the rear vortex in dual vortices and the back pressure circulation Γ b, which is defined as a form of overpressure circulation Γ p. The Γ b has a positive linear relationship with Γ p. A critical interval distance d cr * in a range of 0.32–0.42 is found where Γ b and Γ p reach the maximum synchronously, leading to a full-interaction mode. Moreover, an over-interaction mode and an under-interaction mode are proposed when the dimensionless interval distance d* is smaller or larger than d cr * . To conclude, the high back pressure caused by vortex interaction can enhance the formation of vortex rings and lead to high thrust.

The intensity of the green line (Fe xiv 5303 Å) is the strongest in the visible spectrum of the solar corona, and this line has been used as long-term powerful diagnostic tools for studying the coronal configurations and hot plasma dynamics. However, it remains unclear and an open question whether there exists close relationship between the green line intensities and the coronal extreme ultraviolet (EUV) line emissions for various coronal structures. In this paper, we use the green-line data by the Lijiang YOGIS Lyot coronagraph and the EUV data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly instruments in order to perform direct comparisons and analyses, based on two algorithms developed to extract particular features in the low corona. It is found that, among the correlation coefficients obtained between the intensities of 5303 Å and the EUV lines, the coefficients between the green line and the 211 Å wavelength for different coronal structures and different limb locations always keep the highest values (ranging from 0.89 to 0.99), which has not been reported before. This result can be helpful and promising to link together the various physical processes involved at different heights in the corona by precisely tracking the bright loops or other features observed in 5303 Å above the limb down to the correct surface locations revealed by the 211 Å data. Furthermore, the ground-based observations of the coronal green line and the space-based EUV observations at 211 Å can advantageously complement each other when there is a need.

Current-carrying sliding is widely applied in aerospace equipment, but it is limited by the poor lubricity of the present materials and the unclear tribological mechanism. This study demonstrated the potential of MoS2-based materials with excellent lubricity as space sliding electrical contact materials by doping Ti to improve its conductivity. The tribological behavior of MoS2-Ti films under current-carrying sliding in vacuum was studied by establishing a simulation evaluating device. Moreover, the noncurrent-carrying sliding and static current-carrying experiments in vacuum were carried out for comparison to understand the tribological mechanism. In addition to mechanical wear, the current-induced arc erosion and thermal effect take important roles in accelerating the wear. Arc erosion is caused by the accumulation of electric charge, which is related to the conductivity of the film. While the current-thermal effect softens the film, causing strong adhesive wear, and good conductivity and the large contact area are beneficial for minimizing the thermal effect. So the moderate hardness and good conductivity of MoS2-Ti film contribute to its excellent current-carrying tribological behavior in vacuum, showing a significant advantage compared with the traditional ones.

In recent years, the concept of Virtual Power Plant (VPP) is becoming more and more popular due to its capability of aggregating Distributed Energy Resources (DERs) and exploring its potential of providing flexibility to the existing power grid. Distributed algorithms have several potential advantages over centralized approaches, such as sharing limited amounts of information, performing parallel computations, and having strong robustness. In this context, this paper surveys the literature of distributed algorithms regarding VPP applications. Firstly, we established the VPP framework and operation control modes. Secondly, the basic distributed algorithms were given. Then, this paper studied distributed algorithms in VPP for economic dispatch, bidding optimization, autonomous control strategy within VPP, coordinated control strategy among muti-VPP, and interactive control strategy with grid side. Finally, the key issues and research potential were analyzed.

The development of global positioning technology and the popularization of smart mobile terminals has led to a trend of rapid growth in the data volume and coverage of trajectory data. This type of data has the characteristics of fast update speed, high dimensional characteristics, and a large amount of information that can be mined. Many technology companies will use trajectory data to provide location-based services, such as vehicle scheduling and road condition estimation. However, the storage and query efficiency of massive trajectory data have increasingly become bottlenecks in these applications, especially for large-scale spatiotemporal query scenarios. This paper solves this problem by designing a trajectory data index model based on GeoSOT-ST spatiotemporal coding. Based on this model, the HBase-based trajectory data storage scheme and spatiotemporal range query technology are studied, and MapReduce is used as the calculation engine to complete the query attribute condition filtering in parallel. Comparative experiments prove that the index model proposed in this paper can achieve efficient trajectory data query management.

Postural synergies have great potential for replicating human grasp characteristics, simplify grasp control and reduce the number of hardware actuators required. However, due to their complex mapping relationship and jagged transmission ratio, the implemented mechanisms are always too bulky and loose, which greatly limits their application. With current solutions, the replication accuracy of motion characteristics or intuitive control is compromised, and hitherto no work in the literature has reported the replication errors. To overcome these limitations, we present a novel design framework to determine the actuation configuration, implementation scheme and physical parameters. In this way, the mechanism is miniaturized and can be compactly embedded in the palm of the hand. A self-contained synergistic robot hand with integrated mechanism, sensors and a suitable electrical system is built. The experiments demonstrate that the robot hand can accurately replicate the motion characteristics of two primary synergies, maintain intuitive control to simplify grasp control, has a good capability for anthropomorphic motion and can grasp different objects with versatile grasp functionality.

A full-scale model was established by the Fire Dynamics Simulator (FDS) to study the fire characteristics in the cable cabin of utility tunnel with different longitudinal fire source locations. Five fire sources at different locations were placed in a 200-meter-long fire compartment. Several important parameters were obtained and analyzed, including temperature distribution, smoke concentration, and fire self-extinguishing. The results present that the fire source located at 1/2 of the longitudinal direction has the largest range of high-temperature smoke, which leads to the largest damage range of the concrete structure. The reverse filling of the smoke in the utility tunnel leads to the longitudinal CO peak concentration first decreasing and then increasing from the fire source to the end. When the fire source is located at 1/8 of the longitudinal direction, the fire self-extinguishing time is the longest. These encouraging results could provide significant references for the fire protection design and fire control of the utility tunnel.

The electronic structure of active sites is of importance for catalysts to achieve an optimized interaction with the intermediates. In this study, a unique organic–inorganic hybrid oxygen evolution reaction electrocatalyst composed of electrochemically inactive conducting polyaniline (PANI) and non-precious Fe-based oxide Fe3O4 is presented. PANI molecules were in situ loaded on Fe3O4 nanoparticles through an efficient and simple process under mild conditions. The electronic structure of Fe3O4 was modulated by creating a strong interaction with PANI molecules, leading to enhanced activity and stability of the catalyst to achieve 10 mA cm−2 geometrical current density at overpotential of 265 mV in 1 M aqueous KOH solution. This work demonstrates that a highly efficient electrocatalyst can be achieved by molecular modification and provides a novel strategy for the optimization of the inactive non-precious catalysts.

Background: Polyimide is one of the organic polymer materials with the best comprehensive performance. It has outstanding mechanical properties, excellent thermal stability and excellent corrosion resistance, but pure polyimide has high coefficient of friction and wear rate. By combining graphene with polyimide, the mechanical properties of the composite are significantly reformatived, and the friction coefficient and wear rate can be reduced. Objective: The molecular models were developed to study the mechanical and tribological properties of graphene as a reinforced material. Methods: In this paper, the mechanical properties and friction and wear mechanism of materials are studied by molecular dynamics method from the microscopic point of view. The Young’s modulus and hardness of composites were calculated using the strain constant method. Results: Molecular dynamics simulation results expressed that the Young’s modulus and hardness of polymer composites benefited by approximately 115% and 42%, respectively, after the addition of the graphene-reinforced material. The average friction coefficient and wear rate of polymer composites fall by 35% and 48%, respectively. Through the calculation and statistics of the micro-information in the process of friction simulation, the internal mechanism of various situations is revealed in the atomic dimension. Conclusions: Graphene can adsorb on the surface of polymer chain segment, a strong polymer matrix, through van der Waals and electrostatic forces and can effectively resist external loading.

Phase-sensitive x-ray imaging continues to attract research for its ability to visualize weakly absorbing details like those often encountered in biology and medicine. We have developed and assembled the first inline-based high-energy phase sensitive breast tomosynthesis (PBT) system, which is currently undergoing patient imaging testing at a clinical site. The PBT system consists of a microfocus polychromatic x-ray source and a direct conversion-based flat panel detector coated with a 1 mm thick amorphous selenium layer allowing a high detective quantum efficiency at high energies. The PBT system scans a compressed breast over 15° with 9 angular projection views. The high-energy scan parameters are carefully selected to ensure similar or lower mean glandular dose levels to the clinical standard of care systems. Phase retrieval and data binning are applied to the phase contrast angular projection views and a filtered back-projection algorithm is used to reconstruct the final images. This article reports the distributions of radiation dose vs. thickness of the compressed breasts at 59kV and 89kV and sample PBT images acquired from 3 patients. Preliminary PBT images demonstrate the feasibility of this new imaging modality to acquire breast images at lower radiation dose as compared to the clinical digital breast tomosynthesis (DBT) system with enhanced lesion characteristics (i.e., lesion spiculation and margins).

We study the global quantum discord (GQD) in the Lipkin-Meshkov-Glick (LMG) model at zero and finite temperatures, in which all spins are mutually interacted and introduced in an external magnetic field (denoted byh). We confirm that the high coordinate number is one of the most distinguishing features of the LMG model, which directly results in the nontrivial behaviors of quantum correlations. We compare the GQD with other quantum correlations measures (such as concurrence, quantum discord, and global entanglement) and find the remarkable difference between them. For instance, we find that GQD spreads in the entire system and captures more information on quantum correlations when comparing with concurrence and quantum (pairwise) discord. We discover that GQD can characterize multipartite correlations in the both broken phase (h 0 in the anisotropic cases for any fixed magnetic field. We further show that GQD behaves asG|sn∼k⋅1N+cwithk< 0 in the isotropic cases for any Dicke state |sn⟩. Hereinkandcare the fitting parameters. We also find that the thermal stability of the GQD at low temperatures depends on the energy gap. We further reveal that the extraordinary behaviors of the thermal-state GQD in the isotropic LMG model are explained by the contribution theory of the energy levels.

In the environment of scientific and technological progress and the wide application of intelligent agriculture, the project designs and implements an intelligent agricultural greenhouse irrigation system based on MCU, which makes the greenhouse planting of crops more convenient and reasonable The main modules of the irrigation system are soil moisture detection module, liquid crystal display module, timer module, MCU control module and watering module. The system detects the soil humidity through the humidity sensor, displays the humidity on the LCD, and drives the watering module to work through the single chip microcomputer control module. The function of timer is to control the watering time and water consumption, and intelligently complete the automatic work of agricultural greenhouse irrigation system. Through this system design, the application of SCM in various fields can be expanded. It makes the irrigation of agricultural greenhouse intelligent. It provides a solid foundation for the construction of green agriculture.

Hierarchical structure is the method and means of data transmission in sensor network system. The large-scale application of sensor network system and a large number of data acquisition will produce massive data. In order to reduce the load of sensor network processor system and make data transmission more reliable and convenient. For the transmission and processing of streaming and structured data, the data can be processed hierarchically and dimensionally. Hierarchical processing can effectively reduce the load of the network system; Dimensionality reduction can effectively compress the amount of data to reduce the time of data transmission and processing. Hierarchical operation is a necessary step for data transmission and processing in sensor networks, and has been applied in large-scale data transmission and processing algorithms.

Understanding the behaviours of ice nucleation in non-isothermal conditions is of great importance for the preparation and retention of supercooled water. Here ice nucleation in supercooled water under temperature gradients is analyzed thermodynamically based on classical nucleation theory (CNT). Given that the free energy barrier for nucleation is dependent on temperature, different from a uniform temperature usually used in CNT, an assumption of linear temperature distribution in the ice nucleus was made and taken into consideration in analysis. The critical radius of the ice nucleus for nucleation and the corresponding nucleation model in the presence of a temperature gradient were obtained. It is observed that the critical radius is determined not only by the degree of supercooling, the only dependence in CNT, but also by the temperature gradient and even the Young’s contact angle. Effects of temperature gradient on the change in free energy, critical radius, nucleation barrier and nucleation rate with different contact angles and degrees of supercooling are illustrated successively. The results show that a temperature gradient will increase the nucleation barrier and decrease the nucleation rate, particularly in the cases of large contact angle and low degree of supercooling. In addition, there is a critical temperature gradient for a given degree of supercooling and contact angle, at the higher of which the nucleation can be suppressed completely.

A signal timing optimization method based on shifted left turn lane intersections is proposed to increase the efficiency of shifted left turn lane junctions. In previous studies, vehicle delays were often the only concern but vehicle exhaust emissions were ignored, which could easily aggravate environmental pollution. A multi-objective optimization model was developed in this paper for intersection signal timing from a vehicle and environmental perspective, using vehicle delay, capacity and exhaust emissions as indicators. A modified particle swarm algorithm was used to resolve the impact of a shifted left turn lane on vehicles at a selected junction in Shanghai. The proposed scheme can reduce vehicle delay by 24.58%, increase traffic capacity by 17.09% and reduce tail gas emission by 34.68% in peak period compared with before improvement. In low peak period, the delay, exhaust emission and traffic capacity are reduced by 49.04%, 41.68% and 17.09% compared with those before improvement. Using this optimization scheme can improve vehicle delay to a certain extent, improve vehicle traffic capacity and reduce pollution caused by exhaust emission to the environment. It also verifies the validity of the model and provides some theoretical basis for setting the signal timing for shifted left-turn lane intersections.

The phase-locking behavior of El Niño-Southern Oscillation (ENSO) in models from Coupled Model Intercomparison Project (CMIP) phase 5 to phase 6 is assessed in terms of the locking-month of ENSO peak and the sharpness of locking tendency. Overall, a robust improvement exists in CMIP6. Compared to CMIP5, more CMIP6 models truly reproduce the locking-month in November-January. Meanwhile, the sharpness of phase-locking in CMIP6 models also improves, though most of them are still far from the observations. The locking-month is verified to be highly corresponding to the phase of seasonal modulation of ENSO’s instabilities. The sharpness is mainly controlled by the intensity of this modulation and noise. Compared to CMIP5, CMIP6 models generally simulate these affecting factors better. Besides, models displaying an exaggerated semi-annual variation of ENSO’s instabilities simulate the ENSO phase-locking relative-poorly, and these models show no reduction from CMIP5 to CMIP6.

In this work, through introducing the first and second derivatives of strain gradient into the strain energy density function that depends only on the classical strain in conventional continuum mechanics theory to describe the microscopic interactions, the elastic wave equations including rotational deformation and strain gradient based on the Aifantis’s strain gradient theory is derived. The elastic wave equations including rotational deformation and strain gradient with consideration of the scale effects caused by the microscopic interactions will make seismograms appear obvious changes, which are reflected in amplitude attenuation and dispersion, especially P-wave and S-wave propagate in a dispersive manner based on this theory. The results of numerical modelling and theoretical analysis verify this conclusion. The closer the wavelength is to the characteristic scale of the media (lattice size and interparticle distance), the macroscopic response which results from the microscopic interactions becomes more prominent. To further study the effects of microstructure interactions, we compare the results of numerical modelling with the real data when high-speed train passed the piers in Dingxing County in both time and frequency domains, some conclusions are drawn from the comparison.

In this work, we simplify a moving high-speed train as combination of a series of the axe loads from the front and rear bogies of cars. We build a simplified bridge pier model, as a result, train source expressions with cars moving on land and bridges are given respectively. Considering that the piers are inserted into the ground at a depth of a few tens meters and reach the bedrock. When the high-speed train passes the piers, the piers will appear oscillating motion which is subjugated by the ground, and this oscillating motion is relative to the microstructure interactions of subsoil and bedrock in the frame of the generalized continuum mechanics theory. Hence, we derive the elastic wave equations based on the modified couple stress theory to perform numerical modelling for a simplified bridge pier model under high-speed train passage over the bridge. Based on the wave equation and the train source expressions, a theoretical seismogram of a moving high-speed train with 16 cars on the bridge are obtained. Compared with the real data recorded when a high-speed train passed the piers in Dingxing County, some conclusions are drawn.

Optical vortices usually carry integer orbital angular momentum (OAM) of light. Recently, optical vortices with rational-order OAMs have also been created continuously for entangling the super-position OAM states of monochromatic light in a single device. Here, we report the broadband generation of such rational-order optical vortex beams by using a bilateral meta-grating. The meta-grating contains two oblique gratings that encode two sign-opposite linear phase profiles in two symmetric sides, thus leading to phase dislocation along the symmetric axis. We reveal that the encoded phase profiles are valid in a range of wavelengths due to the broadband response of the meta-grating. The measured phase, intensity and tilting angles match perfectly with theoretical prediction, suggesting the bilateral meta-grating as a powerful device to create broadband and continuous OAM of light for various applications such as optical micro-manipulation, optical communication, quantum physics, and super-resolution imaging.

Aiming at the lack of a systematic research method on the distribution of ring station in the existing 10kV urban medium voltage distribution network research, a method of ensuring the location and capacity of ring station based on the weighted Voronoi diagram is proposed. First, analyze the location and capacity of ring station based on the structure of the urban medium-voltage distribution network; Second, in view of the location and capacity of the ring station of the urban medium voltage distribution network, the line investment of the upper-level to the ring station, the investment cost of the ring station, and the line investment of the lower-level to the ring station are comprehensively considered, and build the mathematical model. Third, a method of ensuring the location selection and capacity determination of ring station based on weighted Voronoi diagrams and a solution process are proposed. Finally, an example is used to verify the effectiveness and practicability of the proposed method.

The staggered-grid finite-difference (SGFD) method is one of the most popular means used in seismic numerical modelling because of its computational efficiency and it is easy to implement. However, it will lead to serious numerical errors while using coarse grids or wavelet with high-frequency. In this work, we proposed an optimal spatial SGFD method based on a new improved particle swarm optimization (PSO) algorithm. Then the dispersion of numerical solution of the first-order spatial derivatives is analyzed. Meanwhile, numerical modelling of elastic wave equations and elastic wave equations including rotational deformation are performed with the optimal spatial SGFD method based on the improved PSO algorithm. Numerical dispersion analysis and numerical modeling results indicate that the optimal spatial SGFD method based on the improved PSO algorithm has high modeling accuracy and can efficiently suppress the numerical dispersion.

Main text The key comparison CCQM-K151 protein quantification: Purity-assessed recombinant protein contents in buffer solution using Insulin analogue was coordinated by Korea Research Institute of Standards and Science (KRISS) under the auspices of the Protein Analysis Working Group (PAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) CCQM. Nine National Metrology Institutes and Designated Institutes participated. Participants were required to assign the mass fraction of human insulin analogue (Ins) present as the main component in the comparison sample for CCQM-K151. This study provided the means for assessing measurement capabilities for determination of purity-evaluated recombinant proteins up to 10 kDa containing up to 3 disulfide cross-links in an aqueous calibration solution using amino acid based ID-LC-MS. Sample purity was confirmed by coordinating lab. Nine results were submitted. All results applied the LC-MS/MS method and isotope dilution mass spectrometry (ID-MS) method for quantification of Ins by amino acid analysis through acid hydrolysis. Among nine results, the Key Comparison Reference Value (KCRV) was assigned with six results. The assigned KCRV was the arithmetic mean of the six results, of 3440 mg/kg with a combined standard uncertainty of 13.5 mg/kg, the k-factor for the estimation of the expanded uncertainty of the KCRVs was chosen as k=2.57. Three participants, reported lower values than the other six, requested another set of test materials for additional experiments to investigate source of discrepancy in their results, and therefore were excluded from KCRV estimation in CCQM-K151. Three participants progressed substantial experiments with further investigation into their negative-biased factor, and actively proved their measurement capability. The degree of equivalence (with the KCRV) and its uncertainty was calculated for each result. Six of the participants were able to demonstrate the ability to quantitatively determine purity-assessed recombinant protein in buffer solution. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The total dissolved gas (TDG) supersaturation observed in a spillway that flows downstream various hydraulic structures has long been recognized as having a negative environmental effect on fish and aquatic organisms. This paper focuses on learning the mass transfer of supersaturation total dissolved gas downstream and the rule of mass transfer between air-water interfaces. Besides, the three main coefficients of mass transfer are concluded: the surface mass transfer coefficient, the bubble interface mass transfer coefficient, and the dissipation coefficient and relevant transport process model. These can provide a foundation to analyze the supersaturation of high dam in near future.

Electron beam melting (EBM) is three-dimensional (3D) printing technologies that can manufacture multi-functional porous scaffolds with exact structures for the application of surgical operations. In the past decade, thousands of acetabular implants manufactured by EBM or SLM have been designed into acetabular cups with certain porosity for surgical operations. Particles of 3D printed porous Ti6Al4V implants will adhere between sintered interface and non-sintered interface of porous sample during 3D printing. However, the internal excess particles of complex structural parts are difficult to remove. During long-term cyclic loading, stress strain can cause residual Ti6Al4V particles to fall off. These detached Ti6Al4V particles are scattered around the implant and are contact with osteoblasts. In our study, we detected the influence of the differentiation concentration of Ti6Al4V particles on bone of rats. The influence of the differentiation concentration of Ti6Al4V particles on bone was evaluated by distal femoral defects in rats. Micro-CT and biochemical analysis were used to evaluate all of the rats after 12 weeks. Outcomes demonstrated that low concentration Ti6Al4V particles may improve the osteogenesis of SD rat through micro-CT. Serum markers implied that the differentiation concentration of Ti6Al4V particles didn’t influence on hepatic and renal functions. In conclusion, Low-dose residual particle does not induce a decrease in bone mineral density (BMD) of rats.

In this paper, the (2 + 1)-dimensional Hunter-Saxton equation is proposed and studied. It is shown that the (2 + 1)-dimensional Hunter–Saxton equation can be transformed to the Calogero–Bogoyavlenskii–Schiff equation by reciprocal transformations. Based on the Lax-pair of the Calogero–Bogoyavlenskii–Schiff equation, a non-isospectral Lax-pair of the (2 + 1)-dimensional Hunter–Saxton equation is derived. In addition, exact singular solutions with a finite number of corners are obtained. Furthermore, the (2 + 1)-dimensional μ-Hunter–Saxton equation is presented, and its exact peaked traveling wave solutions are derived.

This paper introduces a novel method to recognize the facial micro-expressions by directly adopting state-of-the-arts deep learning algorithms. Specifically, genetic algorithm (GA) is applied based on the principles of evolution in searching an optimal solution to generate discriminant features. Prior to that, the feature vectors of each video are first encoded using existing apex-based feature descriptors, viz, Bi-WOOF, OFF-ApexNet and STSTNet. Then, GA is utilized to enrich the features by eliminating irrelevant information that do not contribute to the expression prediction. It is acknowledged that the overfitting phenomena can be avoided in the feature selection process, as GA employs tournament selection and deterministic mutation procedures during the evolution procedure. As a result, Genetic Algorithm in Apex Frame Network (GA-ApexNet) is introduced and significant improvement of the recognition performance has been achieved. A standard experimental configuration is designed to evaluate the robustness of the proposed framework. Following the suggestion in Facial Micro-Expressions Grand Challenge (MEGC 2019), the UF1 and UAR obtained are 78.85% and 78.28%, for the composite dataset that comprises CASME II, SMIC and SAMM. We also note that this is the first work that fuses GA in micro-expression recognition system.

In this study, we use a two-dimensional clustering methodology to identify the high-and low-speed structures of the streamwise wall-shear fluctuations in turbulent channel flows at different Reynolds numbers. The statistical properties of the high- and low-speed structures, such as geometrical characteristics, fluctuating intensities and conditional velocity fluctuations, are shown to be remarkably asymmetrical. The low-speed structures are closely related with the celebrated attached eddies. Our work may aid to the future development of the attached-eddy model.

By changing the thickness of the column, the axial compression behavior of the one-side sheathed wall and the both-sides sheathed wall can be altered at different levels. Simulation and inspection of cold-formed thin-walled steel frame wall had been finished by using a finite element simulation software called ABAQUS, which was applied by test data from relevant literature. The axial carrying capacity of the sheathed wall was superior than the unsheathed wall, therefore, all models had been built and studied based on the one-side sheathed wall and both-sides similar sheathed wall. The analysis results proved that the axial compression behavior of the one-side sheathed wall and the both-sides sheathed wall could be increased substantially by adding the thickness of studs, and this change was more sensitive to the influence of the wall with one-side sheathed wall especially.

With the booming development of the shipbuilding industry, ship design process more and more attention to the design of marine diesel engine explosion-proof valve. However, the research on the explosion-proof valve has been stuck in the test of the state of the explosion gas outlet, and the relevant experimental data for the state of the explosion gas entering the explosion-proof valve is lacking. In this paper based on the CFD simulation platform, the explosion of the test vessel of the explosion-proof valve test system is simulated. And the explosion process of premixed gas in test vessel is effectively simulated by establishing the basic combustion model of gas combustion explosion, using the symmetry of the container, and giving the reasonable boundary conditions. The process simulation of gas explosion pressure data and pressure data measured by explosion experiments comparative analysis proved the reliability of the simulation results, provided the initial conditions for further study of the explosion-proof valve, a very important reference for the further study of the explosion-proof valve.