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This paper continues to study the construction of uni-nullnorms on bounded lattices. At first, we introduce a new method for constructing the smallest uni-nullnorm on an arbitrary bounded lattice L having the elements e , a ∈ L , based on the existence of a uninorm on [ 0 , a ] 2 with the neutral element e and a triangular norm on [ a , 1 ] 2 . And then, we propose another new approach to obtain the largest uni-nullnorm on L via a uninorm on [ 0 , a ) 2 with the neutral element e and a triangular norm on [ a , 1 ] 2 . Furthermore, we provide some corresponding examples to illustrate that our construction methods differ from the existing ones.

The technology of using high abundance rare earth element Ce in permanent magnets has attracted many concerns. In this work, the magnetic properties and microstructures of hot deformed (Nd1-xCex)13.8Fe76.1Co4Ga0.5B5.6 magnets and a selective magnet treated with PrCu grain boundary diffusion process (GBDP) were investigated systematically. It is found that Ce is beneficial to improving the plastic deformation ability of NdFeB magnets. The strongest c-axis orientation is achieved in the HD magnets with Ce concentration of x = 0.3, resulting in good comprehensive magnetic properties of Br = 13.00 kGs, Hcj = 10.12 kOe, (BH)max = 38.42 MGOe. Based on that, the GBDP was implemented on the magnets with the best orientation using Pr68Cu32 ribbons and the magnetic properties of Br = 12.87 kGs, Hcj = 15.65 kOe, (BH)max = 37.48 MGOe were obtained. The results of composition distribution and Curie temperature test of the GBDPed magnets illustrate that Pr diffuses into the (Nd,Ce)2(Fe,Co)14B grains to substitute Ce, which not only improves the Curie temperature of the grains, but also enhances the magnetic performance of the magnets. Through GBDP, the thermal stability of magnets has also been improved.

Quartz and clay are substituted gradually by fly ash using a triaxial ceramic formulation under simulated industrial conditions and the effects of fly ash substitution on the macroscopic properties and microstructures of the sintered ceramics are evaluated systematically. With the substitution of 35 wt% (1250 °C), the ceramic sample exhibited optimal properties, including linear shrinkage of 15.61%, bulk density of 2.39 g cm-3, water absorption of 0.62% and flexural strength of 41.70 MPa, due to the accelerated densification and fly ash-spurred needle-shaped mullite. The microstructure analysis shows that the sintered matrix consists of three types of particles, quartz-, clay- and feldspar-like particles showing sintering behavior with respect to filling the glassy matrix with preserved morphology, precipitating mullite crystals, and fusing with the surrounding glassy matrix, respectively. The strength of the fly ash - containing ceramics is analyzed by the dispersion-strengthening mechanism and porosity and the results indicate that the fly ash particles affect the mechanical strength due to Griffith flaws when the total porosity is less than 25% and pores at higher total porosity. This study provides a viable strategy to recycle industrial fly ash in the production of architectural ceramics.

Lithium metal-based secondary batteries are very promising for next generation power battery due to their high energy density. However, lithium anodes suffer from poor electrochemical reversibility in organic electrolytes due to Li dendrites and instability of the solid electrolyte interphase. Recent research demonstrated that the problem can be alleviated via tetraethoxysilane (TEOS) treated lithium metal to form a silicon oxide layer on the lithium surface, however, its reaction mechanism is controversial. Herein, we deeply explore the reaction mechanism between TEOS and Li and propose: Fresh Li can directly react with TEOS even though no lithium hydroxide exists on the lithium surface, and the participation of water will accelerate the reaction process. Moreover, it was found that the silicon oxide layer can promote the uniform deposition of lithium ions by providing lithiophilic nucleation sites, thereby achieving a long cycle life of Li metal batteries.

Mobile advertising plays a vital role in the mobile app ecosystem. A major threat to the sustainability of this ecosystem is click fraud , i.e., ad clicks performed by malicious code or automatic bot problems. Existing click fraud detection approaches focus on analyzing the ad requests at the server side. However, such approaches may suffer from high false negatives since the detection can be easily circumvented, e.g., when the clicks are behind proxies or globally distributed. In this paper, we present AdSherlock, an efficient and deployable click fraud detection approach at the client side (inside the application) for mobile apps. AdSherlock splits the computation-intensive operations of click request identification into an offline procedure and an online procedure. In the offline procedure, AdSherlock generates both exact patterns and probabilistic patterns based on URL (Uniform Resource Locator) tokenization. These patterns are used in the online procedure for click request identification and further used for click fraud detection together with an ad request tree model. We implement a prototype of AdSherlock and evaluate its performance using real apps. The online detector is injected into the app executable archive through binary instrumentation. Results show that AdSherlock achieves higher click fraud detection accuracy compared with state of the art, with negligible runtime overhead.

LiFePO4 modified by N-doped graphene (NG) with a three-dimensional conductive network structure was synthesized via a one-step in situ hydrothermal method. The effects of N amount of NG on the phase structure, morphology, and electrochemical properties of LiFePO4 are investigated in this study. X-ray diffraction (XRD) results show that doping suitable N amounts in NG do not alter the crystal structure of LiFePO4, and scanning electron microscopy (SEM) images show that NG can slightly reduce the particle size of LiFePO4. The high-resolution transmission electron microscopy (HRTEM) results show that the LiFePO4 particles are well covered and connected by NG. The electrochemical performance confirms that LiFePO4 modified by 20% N-doped graphene (named LFP/NG-4) displays a perfect specific capacity of 166.6 mAh·g−1 at a rate of 0.2C and can reach 125 mAh·g−1 at a rate of 5 C. Electrochemical impedance spectroscopy (EIS) results illustrate that the charge transfer resistance value of the LFP/NG-4 composite is only 58.6 Ω, which is very low compared with LiFePO4. Cyclic voltammetry (CV) tests indicate that the addition of 20% N-doped graphene can effectively reduce electrode polarization and improve reversibility. The LFP/NG-4 composite with a three-dimensional conductive network structure can be regarded as a promising cathode material for Li-ion batteries.

It is approved that grain boundary diffusion is an effective method to increase the coercivity of hot-deformed NdFeB magnet. In this paper, a new rare earth-free grain boundary diffusion source of hot-deformed magnet was studied. AlCuZn powders blended with commercial NdFeB powders were hot-compacted to obtain fully dense magnets, hot-deformed into anisotropic magnets and finally annealed to gain better homogeneity. Initially, the influences of annealing temperature and time on the magnetic properties of the specimens were studied and the optimal parameters of 600 °C and 60 min were achieved. Then, by changing the proportions of AlCuZn grain boundary diffusion, the coercivity, remanence and maximum energy product of the hot-deformed NdFeB magnets were examined. The result showed that with 1.0 wt% AlCuZn grain boundary diffusion and annealing at 600 °C for 60 min, the coercivity rose from 828 to 987 kA·m−1 without deteriorating the remanence. Microstructural analysis confirmed that AlCuZn diffused into the intergranular boundaries and the magnet diffused with AlCuZn possessed finer grains than that of without AlCuZn grain boundary diffusion.

Cysteine (Cys) is a crucial biomarker and plays various significant roles in many physiological and pathological processes. Here is reported a fluorescent probe Mito-cys by incorporating o-chlorobenzoic acid ester onto a hemicyanine platform. The probe exhibited excellent specificity and rapid response for cysteine. The developed method quantitatively monitored cysteine from 5 μM to 30 μM with a detection limit of 135 nM. The probe was also employed to image trace endogenous cysteine in living HeLa cells.

Accurate segmentation of the right ventricle (RV) from cardiac magnetic resonance imaging (MRI) images is an essential step in estimating clinical indices such as stroke volume and ejection fraction. Recently, image segmentation methods based on fully convolutional neural networks (FCN) have drawn much attention and shown promising results. In this paper, a new fully automatic RV segmentation method combining the FC-DenseNet and the level set method (FCDL) is proposed. The FC-DenseNet is efficiently trained end-to-end, using RV images and ground truth masks to make a per-pixel semantic inference. As a result, probability images are produced, followed by the level set method responsible for smoothing and converging contours to improve accuracy. It is noted that the iteration times of the level set method is only 4 times, which is due to the semantic segmentation of the FC-DenseNet for RV. Finally, multi-object detection algorithm is applied to locate the RV. Experimental results (including 45 cases, 15 cases for training, 30 cases for testing) show that the FCDL method outperforms the U-net + level set (UL) and the level set methods that use the same dataset and the cardiac functional parameters are computed robustly by the FCDL method. The results validate the FCDL method as an efficient and satisfactory approach to RV segmentation.

This paper outlines progressive damage characteristics of screwed single-lap CFRPI-metal joints subjected to tensile loading at RT (room temperature) and 350°C. Quasi-static tensile tests were performed on screwed single-lap CCF300/AC721-30CrMnSiA joint at RT and 350°C, and the load versus displacement curve, strength and stiffness of joint were gauged and discussed. With due consideration of thermal-mechanical interaction and complex failure mechanism, a modified progressive damage model (PDM) based on the mixed failure criterion was devised to simulate progressive damage characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint, and simulations correlate well with experiments. By using the PDM, the effects of geometry dimensions on mechanical characteristics of screwed single-lap CCF300/AC721-30CrMnSiA joint were analyzed and discussed.

We report herein a new fluorescent probe for the selective recognition and determination of dodine among 20 different pesticides. This fluorescent probe was assembled through host-guest complexation between cucurbit[10]uril (Q[10]) and aminopropyl-1-pyrenebutanamide (PBA) and is designated as PBA@Q[10]. Addition of dodine to PBA@Q[10] results in a dramatic enhancement of fluorescence intensity at 390 nm, accompanied by fluorescence quenching at 488 nm. On this basis, the detection limit is 6.78 × 10−7 mol/L. The response mechanism is a competitive interaction: dodine occupies the cavity of Q[10] and forces PBA to leave.

Two different ways were used to control the distribution of cerium for the enhancement of coercivity. One was by coating CeNdCu in the prepared magnet and annealing to make CeNdCu diffuse into the grain boundary to increase the coercivity, the other was by mixing CeNdCu with initial magnetic powders and then preparing the hot-deformed magnet. The SEM-EDS result indicates that cerium diffuses more easily into the main phase by the mixing way, while cerium is mainly distributed in the grain boundary via the coating way. The heat-treatment process may be one of the dominant influencing factors for the distribution of Ce. Multi-steps heat treatment in the mixing way, consisting of hot-pressing, hot-deforming and post heat process, easily introduces Ce into the main phase Nd2Fe14B, which forms the Ce2Fe14B shell resulting in the decrease of HA. But the coating way can ensure uniform dispersion of Ce in the grain boundary, which leads to the high coercivity.

Large-scale group decision-making (LSGDM) under a social network context has attracted much attention in the field of decision science. The clustering of individual opinions and the handling of trust relationships are the main research topics. Opinion similarity and trust relationship are considered to be two important measurement attributes for implementing clustering. Traditional clustering methods often use a single attribute to divide the original group without requiring a combination of the above two attributes. However, these two attributes play different roles in the clustering process, insofar as opinion similarity is used to measure the level of difference among individual opinions, whereas the trust relationship represents the trustworthiness of decision makers. This paper develops a trust-similarity analysis (TSA)-based clustering method to manage the clustering operation in LSGDM events under a social network context. First, the trust-similarity matrix is established to collectively describe the decision information. Second, all measurement attribute values are mapped to a trust-similarity plot from which the joint threshold can be calculated. Finally, a TSA-based clustering method is proposed that considers the attributes of opinion similarity and trust relationship and that allocates their importance to achieve specific clustering objectives. The numerical experiment and comparative analysis reveal the feasibility and advantages of the proposed method.

Automatic modulation recognition (AMR) plays a vital role in modern communication systems. This letter proposes a novel three-stream deep learning framework to extract the features from individual and combined in-phase/quadrature (I/Q) symbols of the modulated data. The proposed framework integrates one-dimensional (1D) convolutional, two-dimensional (2D) convolutional and long short-term memory (LSTM) layers to extract features more effectively from a time and space perspective. Experiments on the benchmark dataset show the proposed framework has efficient convergence speed and achieves improved recognition accuracy, especially for the signals modulated by higher dimensional schemes such as 16 quadrature amplitude modulation (16-QAM) and 64-QAM.

The measurement of the centroid is of great significance to improve the control performance and reduce the energy consumption of the planetary rover (PR). The uncertainty is an essential indicator of the reliability of centroid measurement results. The purpose of the current study is to evaluate the uncertainty of centroid measurement in the multi-configuration rover. For the measurement of the centroid, the model with 37 parameters of two measurements as the input and the centroid coordinates as the output is derived. Further, the mechanical and electrical integrated system is developed, which can measure the centroid of PRs in different configurations and sizes. Moreover, to overcome the shortcomings of the Monte Carlo method (MCM) in uncertainty evaluation, an adaptive algorithm that automatically determines the number of input sequences is proposed. On this basis, an adaptive quasi-Monte Carlo method (AQMCM) is presented in order to accelerate the uncertainty evaluation, which is characterized by the randomized Sobol sequence. Besides, experiments are performed to compare the uncertainty evaluation process and results of the AQMCM and the adaptive Monte Carlo method (AMCM) in multiple configurations. The result shows that the standard uncertainty of the AQMCM is almost the same as that of the AMCM, but the sequence size of AQMCM is evidently smaller than that of AMCM. Taken together, we identify that the AQMCM evaluates the uncertainty of CM for the multi-configuration rover in an efficient and fast way. Furthermore, the AQMCM provides a new method for uncertainty evaluation, particularly for nonlinear models in different states.

Gear roll forming process is an innovative near-net-shape gear manufacturing technology for efficient manufacturing, high material utilization rate, high products strength, and outstanding surface quality. The profile of the Tooth of the Rolling Tool (TRT) has a direct impact on its strength/stiffness which further affects its life duration and the accuracy of the formed products. Research has been carried out to design the involute curve of TRT, however, the transaction curve of TRT which also has a significant impact on tooth strength and service durability remains to be designed and optimized in order to further improve the rolling performance. In this paper, an elliptical gear tooth root transaction curve is proposed to replace the traditional fillet curve for the enhancement of tooth bending performance. The maximum root stress and stiffness of the gear tooth with elliptical transaction curve are calculated and compared to the standard profile with different parameters (modulus, pressure angle, and coefficient of bottom clearance). The results show that proposed elliptical tooth reduces the maximum root stress and increase the strength and stiffness of TRT especially significant for rolling tools with small number of teeth and coefficient of bottom clearance.

A physical model consisting of two parallel street canyons with the fire room located in the windward side of the first street canyon was established. Large eddy simulation (LES) was employed to investigate the effects of air pollutant dispersion caused by the fire-induced buoyancy plume on the indoor and outdoor air quality. The effect of thermal buoyancy was firstly taken into account by burning the smoke cakes in wind-tunnel experiments under different Fr (Froude number) cases. Results show that the diffusion characteristics of smoke plume, temperature and velocity distributions by wind-tunnel measurements agreed well with the numerical models. According to the smoke soot’s effects on two street canyons, the dispersion of fire pollutants can be divided into three regimes. There exist two critical Fr, Frcrit,1 = 0.313 and Frcrit,2 = 0.389, at which the smoke plume begins to influence the 1st and 2nd street canyons, respectively. Moreover, the region areas of w

Controlling the phases and structure of nanostructured rare-earth-based permanent magnets is essential to develop magnets with high performance in clean energy technologies. Importantly, simultaneously controlling the texture and morphology of nano-grains can lead to both high coercivity and high maximum energy product in the nanostructured magnets. Here, we demonstrated the use of electron-beam exposure (EBE) as a rapid heating technique to control the crystallization of the Pr-Fe-B magnet. Due to the effect of the extremely high heating rate, EBE can be adapted to control the phase, grain size, and morphology of the amorphous precursor as well as the texture of Pr-Fe-B nano-grains. A quasi-texture nanostructure with optimal magnetic exchange interactions is thus achieved, leading to a record-high coercivity of 29.1 kOe at room temperature. We further applied the Landau model and Coble-Creep model to explain the positive impact of the EBE on the crystallization and microstructure of the Pr-Fe-B magnet.

The hot-deformed magnets processed from nanocrystalline/amorphous Nd–Fe–B powders were prepared under different hot-pressing temperatures (600–750 °C, at intervals of 25 °C) by the self-made hot-pressing equipment. The microstructure and magnetic properties of hot-deformed magnets prepared at different temperatures were also investigated. When the temperature is above 650 °C, the density of magnet reaches 7.5 g·cm−3. The optimum magnetic properties of magnetic induction intensity of Br = 1.3 T, optimum energy product of (BH)max = 282.5 kJ·m−3, intrinsic coercivity of Hcj = 1130.0 kA·m−1 of hot-deformed magnets are obtained at hot-pressing temperature of 650 °C. X-ray diffractometer pattern shows that the (00L) texture has been obtained. For the microstructural characteristic, on the one hand, the good magnetic performance is attributed to the fine platelet-like grains with an average length of 410–440 nm at the hot-pressing temperature range from 625 to 675 °C. On the other hand, the unaligned coarse grains are observed in all the samples. And the areal fraction of those is gradually increasing with the rise of the hot-pressing temperature, which tends to deteriorate the magnetic properties. The composition map shows the accumulation of Nd/Pr-rich phase in the coarse grains’ region.

LiFe1-xNixPO4/C composites were successfully synthesized by a simple hydrothermal method. X-ray diffraction (XRD) data indicate that doped Ni can enhance the crystallinity of the composite and retain the olivine lattice type of LiFePO4. The scanning electron microscopy (SEM) results show that a suitable amount of doped Ni can promote the formation of a uniform and small morphology. The high-resolution transmission electron microscopy (HRTEM) results verify that the Ni-doped sample is well covered by a carbon layer and has a high crystallinity. Charge/discharge data reveal that an appropriate amount of doped Ni can improve electrochemical performance. The LiFe0.97Ni0.03PO4/C composite has the strongest intensity of the XRD peaks, the smallest particle size, highest capacity and best cycling performance. Its specific capacity is 169.5 mAh·g−1 at 0.2C and can reach 122.9 mAh·g−1 at a 5C rate. Even at 10C, the capacity retention ratio is still 93.9% after 200 cycles. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) data indicate that the electrode polarization and electrochemical impedance of LiFe0.97Ni0.03PO4/C are reduced compared with pure LiFePO4. Its specific capacity at 0.2C can be 175.8 mAh·g−1 after sufficient activation, which is higher than the theoretical value of 170 mAh·g−1.

Devices operating with excitons have promising prospects for overcoming the dilemma of response time and integration in current generation of electron- or/and photon-based elements and devices. Although the intrinsic properties including edges, grain boundaries, and defects of atomically thin semiconductors have been demonstrated as a powerful tool to adjust the bandgap and exciton energy, investigating the intrinsic modulation of spatiotemporal dynamics still remains challenging on account of the short exciton diffusion length. Here, we achieve the attractive remote lightening phenomenon, in which the emission region could be far away (up to 14.6 μm) from the excitation center, by utilizing a femtosecond laser with ultrahigh peak power as excitation source and the edge region with high photoluminescence efficiency as a bright emitter. Furthermore, the ultrafast transition between exciton and trion is demonstrated, which provides insight into the intrinsic modulation on populations of exciton and trion states. The complete cascaded physical scenario of exciton spatiotemporal dynamics is eventually established. This work can refresh our perspective on the spatial nonuniformities of CVD-grown atomically thin semiconductors and provide important implications for developing durable and stable excitonic devices in the future.

In present study, the optimal condition of prepared drug was determined by response surface methodology. In addition, their physicochemical properties, drug release and uptake ability of CS-MWCNT-HEP were studied, and the distribution of the drug in ICR mice and the sites of action were further evaluated. Under the optimal condition, the mean experimental loaded efficiency 68.55 ± 1.47% was corresponded well with the predicted value of 68.28%. The results of in vitro experiments proved that a release of the drug in a pH-dependent behavior. Flow cytometry and inverted microscope showed that the uptake of CS-MWCNT-HEP in Raw264.7 cells increased significantly as the time increased. In vivo experiment proved that the HEP and CS-MWCNT-HEP were mainly accumulated in the kidney, shown the characteristics of kidney metabolism. On the other hand, the extended retention of CS-MWCNT-HEP in the mice could enhance the immune function. CS-MWCNT-HEP has high loaded efficiency and pH-responsive drug released, which could significantly improved the body's immunity and enhance the body's ability to absorbed drugs. These findings proposed a well characterized novel CS-MWCNT-HEP formulation as drug delivery system, and its mechanism and application will be further investigated in our undergoing studies.

The removal of magnesium from garnierite in Yuanjiang area of Yunnan was performed by carbothermal reduction in vacuum. The effects of reduction temperature and reduction time on the removal rate of magnesium were investigated. The kinetics of the removal of magnesium by carbothermal reduction in vacuum was studied. The thermodynamic calculation results show that it is feasible to remove magnesium from garnierite by carbothermal reduction in vacuum. The experimental results show that the removal rate of magnesium in garnierite can reach 93.23% under the conditions of 1823K for 120min. The reduction process conforms to the chemical reaction kinetics model, which indicated that the reduction process is controlled by chemical reaction and whose expression is 1-(1-α)1/3=(-22850.1/T+2.6296) t, the apparent activation energy (Ea) and the pre-exponential factor (A) are 189.97 kJ/mol and 13.87 s-1, respectively. The results of XRD and SEM analysis show that the condensate obtained by carbothermal reduction in vacuum of the garnierite is magnesium, which is mainly obtained by the reduction reaction between magnesium silicate produced by the decomposition of serpentine in minerals and coal. At the same time, it is proved that it is feasible to directly extract magnesium metal from the garnierite.

Ferromagnetic microwires are feasible building blocks for the construction of electromagnetic composites with tunable left-handed response towards external stimulus. In this work, a typical left-handed signature of the transmission window was revealed in Co-rich microwires ranging from 9.3 to 10.4 GHz, which arised from the ferromagnetic resonance under a constant DC magnetic field of 8 Oe. Such window was modulated by applying a DC current which tended to compensate the magnetic anisotropy of the microwires. Currents of up to 100 mA were applied to the wire resulting in a maximum transmission bandwidth at 60 mA. Such effect was corroborated by the competition between magnetic domains restoration and Joule effect in the presence of DC current. Embedding the microwire into fibre-reinforced 913 E-glass prepregs realised a metacomposite with a corresponding window in 8.5–10.2 GHz benefited by the restoration of circumferential domain structures during the composite curing process. Further, it was observed a dependence of electromagnetic behaviour on the angle between the microwire and the reinforcing glass fibers of the matrix. This investigation provides essential guidance for designing and tuning frequency-selective wave transmitting structures for potential sensing and cloaking applications.

In this study, the structure characteristic of the Hericium erinaceus polysaccharide (HEP) was investigated using Fourier transformed infrared spectrometry (FT-IR), gas chromatography-mass spectrometry (GC–MS), gel permeation chromatography (GPC), methylation and nuclear magnetic resonance (NMR). The results showed that HEP, with a molecular weight of 43 KDa, was mainly composed of glucose and rhamnose. The linkages of the sugar residues of HEP were → 6) β- d -Glcp-(1 → and → 2) -α- l -Rhap-(1 → residue at the end of the branches. The Fusarium toxin deoxynivalenol (DON)-induced cellular injury model for IPEC-J2 cells was established and used to investigate the protective effects of HEP against the oxidative stress. The results suggest that HEP could significantly protect IPEC-J2 cells from DON-induced oxidative stress, inhibit DON-induced apoptosis and reduce the production of reactive oxygen species (ROS). Overall, this study suggested that HEP could be explored as potential antioxidant agents for DON-induced intestinal mucosa injury.

Metamaterials possess attractive electromagnetically left-handed properties yet their nature as an artificial structure rather than a material restricts their further applications. In this article we propose to use Co-based ferromagnetic microwires as periodical metamaterial units interweaved into a fabric to realize a “metacomposite” for steering wave propagation. By introducing ferromagnetic microwires in quartz fabric at three curvatures and periodic lengths, the electromagnetic response and microwave behaviors on both horizontally- and vertically-arranged directions were presented and investigated. Tensile behaviors of metacomposites with different ferromagnetic microwire morphologies were monitored by non-contact full field strain measurement system. At X band (8.2–12.4 GHz), metacomposites containing vertically-arranged ferromagnetic microwires show negative permittivity due to the dielectric resonance of microwire arrays. The dielectric response of metacomposites conformed to Lorentz-oscillator mode, behaving similarly to diluted plasma. When ferromagnetic microwires reached the lowest periodic curved length 2.5 mm with the highest curvature was obtained, the metacomposites presented the maximum microwave absorption of 34% and tensile stress of 273 MPa. The incorporation of ferromagnetic microwires exerts trivial influence on the mechanical properties yet homogenizes the strain and reduces the stress concentration on metacomposites. The metacomposite with a periodic curved length of 7.5 mm has less interweaving points and the highest surface float length, therefore achieving the maximum tensile strength of 458 MPa. The single negative metacomposites containing ferromagnetic microwires are featured with excellent structural properties and amenable microwave left-handed properties in controlling wave-propagating behavior, which is of practical engineering significance in structural health monitoring, sensing and stealth applications.

Summary Temporary plugging during fracturing operations has become an efficient method to create a complex fracture network in tight reservoirs with natural fractures (NFs). Accurate prediction of the network-propagation process plays a critical role in plugging- and fracturing-parameter optimization. In this paper, the interaction between one single hydraulic fracture (HF) within a temporary plugging segment and multiple NFs was simulated using a complex fracture-development model. A new opening criterion for an NF penetrated by a nonorthogonal HF already was implemented to identify the dominant propagation direction of a HF under plugging conditions. Fracture displacements and the induced-stress field were determined by the 3D displacement-discontinuity method, and the Gauss-Jordan and Levenberg-Marquardt methods were combined to handle the coupling between rock mechanics and fluid flow numerically. Numerical results demonstrate that the opening and development of an NF are mainly dominated by its approaching angle and relative location. For a certain NF crossed by an HF within the plugging segment, the HF tends to propagate along the NF branch inclined in the main HF direction. The farther the interaction position is away from the HF tip, the easier the NF with an approaching angle less than 30° or larger than 150° can be open, and the outcome will be opposite if the approaching angle is larger than 45° or less than 135°. Higher approaching angle and plugging strength is necessary for expanding the position scope of NF that can be opened around HF. Under the effect of plugging, fluid pressure in the HF plummets at the beginning of the NF opening and keeps decreasing until the NF extends for a certain distance or encounters secondary NFs. Fluid-pressure drop occurs mainly in the unturned NF, together with the width of unturned NF being significantly lower than that of the turned NF and HF. Sensitivity analysis shows that the main factors, such as geometry, aperture profile, and fluid-pressure distribution, affecting the network progress under the temporary plugging conditions are the horizontal differential stress, NF position, approaching angle, plugging time, and plugging-segment length. The simulation results provide critical insight into complex fracture-propagation progress under temporary plugging conditions, which should serve as guidelines for well choosing and plugging optimization in temporary plugging fracturing.

The manifold microchannel (MMC) heat sink has become the most popular one among emerging technologies for high heat flux thermal management because of its high surface-to-volume ratio. Even though ...

Unmanned surface vehicle (USV) is currently a hot research topic in maritime communication network (MCN), where de-noising and semantic segmentation of maritime images taken by USV have been rarely studied. The former has recently researched on autoencoder model used for image denoising, but the existed models are too complicated to be suitable for real-time detection of USV. In this paper, we proposed a lightweight autoencoder combined with inception module for maritime image denoising in different noisy environments and explore the effect of different inception modules on the denoising performance. Furthermore, we completed the semantic segmentation task for maritime images taken by USV utilizing the pretrained U-Net model with tuning, and compared them with original U-Net model based on different backbone. Subsequently, we compared the semantic segmentation of noised and denoised maritime images respectively to explore the effect of image noise on semantic segmentation performance. Case studies are provided to prove the feasibility of our proposed denoising and segmentation method. Finally, a simple integrated communication system combining image denoising and segmentation for USV is shown.

A near-infrared (NIR) and water-soluble probe was synthesized and studied for the detection of Cys/Hcy in aqueous solution, living cells and mice. The probe was composed of cyanine derivative as the NIR fluorescent reporting unit and pyrimidiny-thioether moiety as the Cys/Hcy responsive unit. Treatment with Cys/Hcy induced the formation of sulfur-substituted products, then intramolecular rearrangement reaction would occur to produce amino-substituted products and resulting in enhanced red fluorescence emissions. It could be applied to sense Cys/Hcy both in solution with the detection limit of 0.17 μM (or 0.32 μM) and in living cells. Cell imaging experiments proved that such a probe exhibited good cell penetration. In addition, the probe could detect Cys/Hcy in live mice with strong turn-on fluorescent response.

© 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Scale-up in droplet microfluidics achieved by increasing the number of devices running in parallel or increasing the droplet makers in the same device can compromise the narrow droplet-size distribution, or requires high fabrication cost, when glass- or polymer-based microdevices are used. This paper reports a novel way using parallelization of needle-based microfluidic systems to form highly monodispersed droplets with enhanced production rates yet in cost-effective way, even when forming higher order emulsions with complex inner structure. Parallelization of multiple needle-based devices could be realized by applying commercially available two-way connecters and 3D-printed four-way connectors. The production rates of droplets could be enhanced around fourfold (over 660 droplets/min) to eightfold (over 1300 droplets/min) by two-way connecters and four-way connectors, respectively, for the production of the same kind of droplets than a single droplet maker (160 droplets/min). Additionally, parallelization of four-needle sets with each needle specification ranging from 34G to 20G allows for simultaneous generation of four groups of PDMS microdroplets with each group having distinct size yet high monodispersity (CV < 3%). Up to six cores can be encapsulated in double emulsion using two parallelly connected devices via tuning the capillary number of middle phase in a range of 1.31 × 10−4 to 4.64 × 10−4. This study leads to enhanced production yields of droplets and enables the formation of groups of droplets simultaneously to meet extensive needs of biomedical and environmental applications, such as microcapsules with variable dosages for drug delivery or drug screening, or microcapsules with wide range of absorbent loadings for water treatment.

In electrical engineering, it is of great importance to monitor partial discharge (PD) of high voltage apparatus. However, on-site PD signal easily gets corrupted by white noise, and hence denoising the measured PD signal is necessary to acquire pure PD. In traditional method, single wavelet and regular thresholding are utilized. By combining wavelets of the same family, dual-tree complex wavelet pairs can be constructed. Specific combinations are approximately translation invariant, and they are also able to achieve better denoising effect without sophisticated computation. Meanwhile, considering the correlation between adjacent wavelet coefficients, the block thresholding is employed. In this paper, it is proposed to combine wavelet pair and block thresholding for PD denoising. There are four combinations based on single wavelet/wavelet pair and regular thresholding/block thresholding, and they are compared with each other. Based on a numerical study, the results demonstrate that the proposed algorithm outperforms the traditional method.

Controlled chemical prelithiation of high capacity phosphorous/carbon (P/C) composite anode has been applied to develop advanced lithium-ion batteries (LIBs). The initial coulombic efficiency (CE) of P/C is significantly improved (up to 93% for fully-prelithiated P/C) owing to the formation of an artificial solid electrolyte interface (SEI) layer, which is characterized by SEM, Raman and XPS analyses. It ensures the application of P/C anode in real battery assembly. A partly-prelithiated P/C anode prepared by 20 s prelithiation treatment is paired with a LiCoO2 (LCO) cathode. The full cell delivers a highly reversible capacity of ~104 mAh g−1LCO at 1C rate and retains a CE close to 100% over 2000 cycles. Moreover, a fully-prelithiated P/C anode prepared by 10 min prelithiation treatment is paired with a high-capacity Li-free sulfur/carbon (S/C) cathode. This newly configured full cell delivers a good rate and cycling performance and a high energy density of 358 Wh kg−1.

Numerous studies have shown that exosomes are closely related to the pathogenesis of various diseases, especially cancers. Therefore, a rapid and sensitive method for exosome detection will be of great importance for the diagnosis and prognosis of diseases. We report here a method for exosome detection based on the CD63 aptamer and clustered regular interspaced short palindromic repeats (CRISPR)/Cas12a system. This method consists mainly of exosomal membrane protein recognition based on the CD63 aptamer and signal amplification based on CRISPR/Cas12a. The CD63 aptamer, as an easily adaptable nucleic acid strand, is responsible for the conversion of the amounts of exosomes into nucleic acid detection, whereas CRISPR/Cas12a is responsible for highly specific nucleic acid signal amplification. The detection range of the method was determined as 3 × 103-6 × 107 particles per microliter. Additionally, we successfully applied this method to detect exosomes in clinical samples from both healthy individuals and patients with lung cancer, and the results were highly consistent with those obtained by nanoparticle tracking analysis. In general, this method provides a highly sensitive and specific method for the detection of exosomes and offers an avenue toward future exosome-based diagnosis of diseases.

In order to improve the detection accuracy of hidden message in images, steganalysis features are selected as inputs for steganalysers. However, the existing Fisher criterion ignores the contribution of steganalysis feature components in dispersion to classification, which causes the useful feature components to be deleted, and decreases the detection accuracy of steganalysis features. By analyzing the separability of steganalysis feature components, we introduce the sigmoid function into Fisher's criterion and propose an improved Fisher criterion (I-Fisher criterion), which can make up for the traditional Fisher criterion in separability measurement of steganalysis feature components. To optimize the steganalysis feature and reduce its dimension, we employ the improved Fisher criterion as the heuristic function of the decision rough set α-positive region reduction, and propose the feature selection method based on the improved Fisher. Experimental results show that the proposed method can reduce the dimension and memory of the GFR high-dimensional feature and the CC-PEV lowdimensional feature while maintaining or improving the detection accuracy.

Energy transfer in heterostructures is an essential interface interaction for extraordinary energy conversion properties, which promote promising applications in light-emitting and photovoltaic devices. However, when atomic-layered transition metal dichalcogenides (TMDCs) act as the energy acceptor because of strong Coulomb interactions, the transferred energy can be consumed by nonradiative exciton annihilations, which hampers the development of light-emitting devices. Hence, revealing the mechanism of energy transfer and the related relaxation processes from the aspect of the acceptor in the heterostructure is key to reducing nonradiative loss and optimizing luminescence. Here, we study the exciton dynamics from the standpoint of the acceptor in MoS2/CdSe quantum rod (QR) heterostructures and realize efficiently enhanced photoluminescence (PL). Through femtosecond pump–probe measurements, it is directly observed that energy transfer from CdSe QRs largely raises the exciton population of the acceptor, MoS2, providing a larger emission “source”. In addition, the dielectric environment introduced by CdSe QRs efficiently enhances the PL by suppressing exciton–exciton annihilation (EEA). This study provides new insights for on-chip applications such as light-emitting diodes and optical conversion devices based on low dimensional semiconductor heterostructures.

MoSe2 is an efficient catalyst for the hydrogen evolution reaction (HER) and can potentially replace conventional catalysts composed of noble metals such as Pt. The HER activity of MoSe2 originates...

This paper focuses on the dynamical characteristics of complex-valued memristor-based BAM neural network (CVMBAMNN) with leakage time-varying delay. With two different controllers, we have obtained fixedtime and finite-time synchronization criteria respectively in complex domain for our special model, which few work has studied before. Since fixed-time synchronous system can improve communication security, we designed a scheme for RGB image encryption and decryption. In order to satisfy the requirement of much lower error in image secure communication, our approach can get the error of fixed-time synchronization to about 1×10−13. Due to our highly consistent system, we do get good encryption and decryption effect with encryption and decryption scheme. Finally, numerical simulations are included to demonstrate the correctness of our theoretical results.

Interface constitutes a significant volume fraction in nanocomposites, and it requires the ability to tune and tailor interfaces to tap the full potential of nanocomposites. However, the development and optimization of nanocomposites is currently restricted by the limited exploration and utilization of interfaces at different length scales. In this research, we have designed and introduced a relatively large-scale vertical interphase into carbon nanocomposites, in which the dielectric response and dispersion features in microwave frequency range are successfully adjusted. A remarkable relaxation process has been observed in vertical-interphase nanocomposites, showing sensitivity to both filler loading and the discrepancy in polarization ability across the interphase. Together with our analyses on dielectric spectra and the relaxation process, it is suggested that the intrinsic effect of vertical interphase lies in its ability to constrain and localize heterogeneous charges under external fields. Following this logic, systematic research is presented in this article affording to realize tunable frequency-dependent dielectric functionality by means of vertical interphase engineering. Overall, this study provides a novel method to utilize interfacial effects rationally. The research approach demonstrated here has great potential in developing microwave dielectric nanocomposites and devices with targeted or unique performance such as tunable broadband absorbers.

Collapsible soils have been regarded to be a significant engineering concern for foundation constructions in northwest China. Given that the collapsible soils, also known as loess, cover most of northwest China, all buildings, structures, and utility pipelines have to deal with the collapse of loess. Despite the many empirically based methods available for evaluation of the collapse of loess, methods to assess the collapse of loess surrounded by piles are, however, rarely seen. This study proposes a simple method for evaluation of the collapse of loess surrounded by piles by taking into account both the collapsible deformation characteristics and friction at the loess–pile interface. The results of an application of the proposed method to three more loess–pile foundation worksites are presented and indicate that the proposed method can predict the settlement of loess–pile foundation satisfactorily.

Bamboo is readily discolored by mold fungi, which greatly limits its applications. An effective antifungal agent, copper(II) chloride (CuCl2)-grafted silica gel, was prepared by a sol–gel process using tetraethoxysilane (TEOS)/3-aminopropyltriethoxysilane (APTES) mixtures. The elemental composition and the chemical combinations of homogeneous sol mixture (HSM) and bamboo were determined via Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy with energy-dispersive X-ray spectrometry (SEM–EDS). The mold resistance of bamboo treated with HSM, alkaline copper quat (ACQ), chromated copper arsenate (CCA), and purified water was characterized by an indoor mold test. The micro-morphology of bamboo treated with HSM was investigated using scanning electron microscopy (SEM). HSM penetrated into the bamboo vessels, and formed xerogels, which was able to coordinate copper(II) cations. SEM–EDS investigations suggest that Si–O–Cu linkages may be formed through an exchange reaction between silanol groups and copper complexes. The bamboo samples treated with HSM showed highly efficient mold resistance due to a good penetration of HSM. Furthermore, no fungal hyphae were found in the structure of HSM-treated bamboo after a 5-week mold test. The copper complexes grafted to silica gel developed in this work provide an efficient antifungal agent for a wide range of potential applications in bamboo protection.

As an important exploration target in the Sichuan Basin, the Lower Triassic Feixianguan Formation has been previously interpreted to be deposited in the trough-platform margin system according to the genetic model of classic lithofacies paleogeography. However, this model does not apply to the northwestern Sichuan Basin. Accordingly, this study proposed a new genetic model that highlighted the carbonate ramp based on the outcrop sections, drilling and logging data, and seismic sections. A large-scale regional regression was found to occur in Sichuan Basin at the end of the Late Permian, leading to the evolution of the original Kaijiang-Liangping Trough into a very shallow tidal flat/lagoon environment at the beginning of the Early Triassic. The sedimentary pattern during the Early Triassic was different from that during the Late Permian. A total of six long-term cycles (LSC1-LSC6) were identified within the Feixianguan Formation. The deposition of LSC1-LSC3 witnessed the filling of the trough to a large extent, and the depositional periods of LSC4 and LSC5 were the main shoal-forming periods. The Feixianguan Formation in the study area was speculated to be deposited in the continuous continental carbonate ramp. With the intensified uplifting of the Longmenshan island chain and the Kangdian ancient land on the northwestern margin of the Upper Yangtze Platform, a large number of terrigenous materials were input into the study area from west to east, leading to the continuous eastward migration of the carbonate facies belt during the deposition of the Fei 1 and Fei 2 Members. Meanwhile, large-area inner-ramp shoal bodies were formed during the deposition of LSC5. It became possible to find a giant gas reservoir belt in the Feixianguan Formation of the northwestern Sichuan Basin and the results of this study provide a new complement to the existing classic trough-platform margin shoal-forming model.

Remote sensing change detection (RSCD) is an important yet challenging task in Earth observation. The booming development of convolutional neural networks (CNNs) in computer vision raises new possibilities for RSCD, and many recent RSCD methods have introduced CNNs to achieve promising improvements in performance. In this paper we propose a novel multidirectional fusion and perception network for change detection in bi-temporal very-high-resolution remote sensing images. First, we propose an elaborate feature fusion module consisting of a multidirectional fusion pathway (MFP) and an adaptive weighted fusion (AWF) strategy for RSCD to boost the way that information propagates in the network. The MFP enhances the flexibility and diversity of information paths by creating extra top-down and shortcut-connection paths. The AWF strategy conducts weight recalibration for every fusion node to highlight salient feature maps and overcome semantic gaps between different features. Second, a novel perceptual similarity module is designed to introduce perceptual loss into the RSCD task, which adds perceptual information, such as structure and semantic information, for high-quality change map generation. Extensive experiments on four challenging benchmark datasets demonstrate the superiority of the proposed network compared with eight state-of-the-art methods in terms of F1, Kappa, and visual qualities.

The manifold microchannel (MMC) heat sink system has been widely used in high-heat-flux chip thermal management due to its high surface-to-volume ratio. Two-phase, three-dimensional numerical methods for subcooled flow boiling have been developed using a self-programming solver based on OpenFOAM. Four different types of manifold arrangements (Z-type, C-type, H-type and U-type) have been investigated at a fixed operational condition. The numerical results evaluate the effects of flow maldistribution caused by different manifold configurations. Before simulating the two-phase boiling flow in MIMC metamodels, single-phase liquid flow fields are performed at first to compare the flow maldistribution in microchannels. It can be concluded from the flow patterns that H-type and U-type manifolds provide a more even and a lower microchannel void fraction, which is conducive to improving the temperature uniformity and decreasing the effective thermal resistance. The simulation results also show that the wall temperature difference of H-type (0.471 K) is only about 10% of the Z-type (4.683 K). In addition, the U-type manifold configuration show the lowest average pressure drop at the inlet and outlet of the MIMC metamodel domain. However, H-type manifold also shows an impressive 59.9% decrease in pressure loss. Results indicate that both the H-type and the U-type manifolds for flow boiling in microchannels are recommended due to their better heat transfer performance and lower pressure drop when compared with Z-type and C-type.

To reduce human risk and maintenance costs, Autonomous Underwater Vehicles (AUVs) are involved in subsea inspections and measurements for a wide range of marine industries such as offshore wind farms and other underwater infrastructure. Most of these inspections may require levels of manoeuvrability similar to what can be achieved by tethered vehicles, called Remotely Operated Vehicles (ROVs). To extend AUV intervention time and perform closer inspection in constrained spaces, AUVs need to be more efficient and flexible by being able to undulate around physical constraints. A biomimetic fish-like AUV known as RoboFish has been designed to mimic propulsion techniques observed in nature to provide high thrust efficiency and agility to navigate its way autonomously around complex underwater structures. Building upon advances in acoustic communications, computer vision, electronics and autonomy technologies, RoboFish aims to provide a solution to such critical inspections. This paper introduces the first RoboFish prototype that comprises cost-effective 3D printed modules joined together with innovative magnetic coupling joints and a modular software framework. Initial testing shows that the preliminary working prototype is functional in terms of water-tightness, propulsion, body control and communication using acoustics, with visual localisation and mapping capability.

There exist some problems such as flow instability and critical heat flux (CHF) caused by the local dryout phenomenon, which is an obstacle to the application of microchannel flow boiling heat sink. Utilizing self-rewetting fluid is one of the promising ways to minimize the dryout area, thus increasing the heat transfer coefficient and CHF. To investigate the heat transfer performance of self-rewetting fluid in microchannel flow boiling, a numerical investigation is carried out in this study using the volume of fluid (VOF) method, phase-change model, and continuum surface force model with surface tension versus temperature. A three-dimensional numerical investigation of bubble growth and merger is carried out with water and 0.2 wt % heptanol solution. The single bubble growing cases, two x-direction/y-direction bubbles' merging cases, and three bubbles' merging cases are conducted. Since the bubbles never detach the heated walls, the dryout area and regions nearby the contact line with thin liquid film dominated the heat transfer process during the bubbles' growth and merger. The self-rewetting fluid can minimize the local dryout area and achieve larger thin liquid film area around the contact line due to the Marangoni effect and thermocapillary force, thus resulting in higher wall heat flux. The two x-direction bubbles' merging case performed best for heat transfer in the microchannel, in which self-rewetting fluid achieves heat transfer enhancement for over 50%.

Accurate and rapid blood typing plays a vital role in a variety of biomedical and forensic scenarios, but recognizing weak agglutination remains challenging. Herein, we demonstrated a flipping identification with a prompt error-discrimination (FLIPPED) platform for automatic blood group readouts. Bromocresol green dye was exploited as a characteristic chromatography indicator for the differentiation of plasma from whole blood by presenting a teal color against a brown color. After integrating these color changes into a quick-response (QR) code, prompt typing of ABO and Rhesus groups was automatically achieved and data could be uploaded wirelessly within 30 s using a commercially available smartphone to facilitate blood cross-matching. We further designed a color correction model and algorithm to remove potential errors from scanning angles and ambient light intensities, by which weak agglutination could be accurately recognized. With comparable accuracy and repeatability to classical column assay in grouping 450 blood samples, the proposed approach further demonstrates to be a versatile sample-to-result platform for clinical diagnostics, food safety, and environmental monitoring.

Abnormal elevated levels of cytokines such as interferon (IFN), interleukin (IL), and tumor necrosis factor (TNF), are considered as one of the prognosis biomarkers for indicating the progression to severe or critical COVID-19. Hence, it is of great significance to develop devices for monitoring their levels in COVID-19 patients, and thus enabling detecting COVID-19 patients that are worsening and to treat them before they become critically ill. Here, an intelligent aptameric dual channel graphene-TWEEN 80 field effect transistor (DGTFET) biosensing device for on-site detection of IFN-I³, TNF-α, and IL-6 within 7 min with limits of detection (LODs) of 476 × 10-15 , 608 × 10-15 , or 611 × 10-15 m respectively in biofluids is presented. Using the customized Android App together with this intelligent device, asymptomatic or mild COVID-19 patients can have a preliminary self-detection of cytokines and get a warning reminder while the condition starts to deteriorate. Also, the device can be fabricated on flexible substrates toward wearable applications for moderate or even critical COVID-19 cases for consistently monitoring cytokines under different deformations. Hence, the intelligent aptameric DGTFET biosensing device is promising to be used for point-of-care applications for monitoring conditions of COVID-19 patients who are in different situations.

Graphene-based supercapacitors have attracted tremendous attention owing to their outstanding electro-chemical performance. In terms of material, nitrogen(N)-doped graphene(NDG) displays enhanced specific capaci- tance and rate performance compared with bare graphene used as a supercapacitor electrode. However, it still remains a challenge to develop a facile and simple method of NDG in cost-effective manner. Here, we used a simple direct laser writing technique to accomplish the simultaneous photoreduction and N-doping of graphene oxide(GO) using urea as a N source. The N content of the resultant reduced N-doped graphene oxide(NGO) reached a maximum value of 6.37%. All reduced NGO(NRGO)-based supercapacitors exhibited a higher specific capacitance than those based on pure reduced GO(RGO). Interestingly, the electrochemical performance of NRGO-based supercapacitors varied with different contents of N species. Therefore, we can control the properties of the obtained NRGOs by adjusting the doping ratios, an important step in developing effective graphene-based energy storage devices.

With the development of thermoelectric (TE) materials with high thermoelectric figure of merit (ZT) values, improved thermoelectric devices have been fabricated recently. Although the performance of thermoelectric generators (TEGs) with segmented legs has been evaluated experimentally, detailed numerical prediction of TEG performance is rarely considered. In this study, a new numerical solution method is devised to analyze a TE couple. We employ the finite volume method, which allows the conservation of thermal energy and electric charge. A computer program based on the numerical method is developed to evaluate the performance of a TEG with a segmented p-leg. Temperature-dependent thermoelectric properties are employed, without simplifying or neglecting Joule heating, Thomson heating, or Peltier heating. The numerical method is discussed in detail, including the derivation of algebraic equations from the integral forms of the governing equations for thermal energy and electric potential. The numerical results obtained with the computer program based on the method are compared with a mathematical solution for validation. Compared with the performance without segmentation, the results show an improvement for the TEG with a segmented leg.