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Accurate electroencephalogram (EEG) pattern decoding for specific mental tasks is one of the key steps for the development of brain-computer interface (BCI), which is quite challenging due to the considerably low signal-to-noise ratio of EEG collected at the brain scalp. Machine learning provides a promising technique to optimize EEG patterns toward better decoding accuracy. However, existing algorithms do not effectively explore the underlying data structure capturing the true EEG sample distribution and, hence, can only yield a suboptimal decoding accuracy. To uncover the intrinsic distribution structure of EEG data, we propose a clustering-based multitask feature learning algorithm for improved EEG pattern decoding. Specifically, we perform affinity propagation-based clustering to explore the subclasses (i.e., clusters) in each of the original classes and then assign each subclass a unique label based on a one-versus-all encoding strategy. With the encoded label matrix, we devise a novel multitask learning algorithm by exploiting the subclass relationship to jointly optimize the EEG pattern features from the uncovered subclasses. We then train a linear support vector machine with the optimized features for EEG pattern decoding. Extensive experimental studies are conducted on three EEG data sets to validate the effectiveness of our algorithm in comparison with other state-of-the-art approaches. The improved experimental results demonstrate the outstanding superiority of our algorithm, suggesting its prominent performance for EEG pattern decoding in BCI applications.

The relationship between activities of involved deformation mechanisms and the evolution of microstructure and texture during uniaxial tension of AZ31 magnesium alloy with a rare non-basal texture has been thoroughly investigated in the present study by means of electron backscattered diffraction (EBSD) measurement and visco-plastic self-consistent (VPSC) modeling. These results show that except basal slip and prismatic slip, { 10 1 ¯ 2 } extension twin (ET) also plays a significant role during plastic deformation. With the increasing tilted angle between loading direction and rolling direction (RD) of sheet, the activity of { 10 1 ¯ 2 } ET possesses a decreasing tendency and its role in plastic deformation changes from the one mainly sustaining plastic strain to the one mainly accommodating local strain between individual grains. When { 10 1 ¯ 2 } ET serves as a carrier of plastic strain, it mainly results in the formation of basal texture component (c-axis//ND, normal direction). By comparison, when the role of { 10 1 ¯ 2 } ET is to accommodate local strain, it mainly brings about the formation of prismatic texture component (c-axis//TD, transverse direction). At large plastic deformation, the competition between basal slip and pyramidal slip is responsible for the concentration of tilted basal poles towards ND within all deformed samples. The larger difference is between the activities of basal slip and pyramidal slip, the smaller separation is between these two tilted basal poles. Besides, VPSC modeling overestimates volume fractions of { 10 1 ¯ 2 } ET in samples with angle of 0 to 30° between loading direction and RD of sheet because interactions between twin variants are not included in VPSC modeling procedure at the present form. In addition, as compatible deformation between individual grains cannot be considered in VPSC modeling, the predicted volume fractions of { 10 1 ¯ 2 } ET in samples with angle of 45 to 90° between loading direction and RD of sheet are smaller than the correspondingly measured results.

To facilitate construction and on-site quality testing, a new type of panel joint using cast-in-place connecting beams was developed and studied. The proposed connecting beams consist of overlapping vertical U-shaped steel bars stretching out of the wall and the footing, longitudinal prestressed steel strands, L-shaped steels and infilled high-strength grout. One monolithic shear wall specimen and five precast specimens were tested under simulated seismic loads. The test parameters studied included the presence or absence of L-shaped steel, sectional depths and the locations of connecting beams and locally non-bonded U-shaped steel bars. The effects of these parameters on the failure modes, hysteresis curves, stiffness, ductility and energy dissipation capacity were evaluated. The test results showed that the precast shear walls with the proposed panel joint achieved desirable seismic behaviour – comparable to or better than that of monolithic specimens – and can thus be safely applied in buildings in seismic zones. The use of L-shaped steel, prestressed steel strands and high-strength grout effectively delayed concrete crushing at the wall toes and thus improved the loading capacity, deformation capacity, initial stiffness, ductility and energy dissipation capacity of the precast shear walls.

This paper proposes an improved design methodology and global optimization method for the design of an advanced dropped-hinge flap (ADHF) using an integrated approach. The approach implemented an a...

Buckling and post-buckling analysis of thin films is significant for the design, optimization and fabrication of stretchable electronic devices based on compression buckling. Aiming to achieve a more accurate and reliable way for the dynamic stability analysis of stiff films considering geometric nonlinearity, an implicit dynamic element-free Galerkin method based on the Strain-Rotation decomposition theorem is developed in this paper to investigate the dynamic buckling behavior of stiff films. Convergence and comparison studies are conducted to validate the numerical stability and accuracy of the proposed numerical method. The influences of compression loading rate and thickness to length ratio on the buckling/post-buckling of stiff thin films subjected to dynamic load are numerically analyzed and discussed in parametric studies. This work provides an effective way for the engineering computation of flexible electronic technology.

In this study, the No. 6 pit in the eastern mining area of the Jinning phosphate mine in China was taken as the research background. In order to reduce the cost of filling, an improved pillarless sublevel caving method is proposed. This method greatly improves the ore recovery rate by adding a recovery route. In addition, the combination of similar material simulation experiments and numerical simulations (discrete element and universal distinct element code) revealed the deformation and failure laws of the surrounding roof rock and the characteristics of the surface subsidence. The results indicate the following. (1) The similar simulation experimental results indicate that the deformation of the overlying rock layer originated from the direct roof of the goaf and gradually developed into the deep part of the rock layer. An irregular stepped caving zone formed in the goaf. The maximum surface subsidence was located above the phosphorus orebody, and it gradually decreased toward both sides. As the stope approached propulsion, the location of the maximum subsidence gradually moved toward the propulsion direction. (2) The numerical results revealed that the displacement of the overlying strata was nonlinear, and it decreased with increasing roof height. A support pressure concentration area was formed within a certain range of the stope roof. The numerical simulation results are basically consistent with the similar simulation experimental results.

PurposeAs users often lack the motivation to contribute their ideas and knowledge in open innovation communities, it is necessary to identify the determinants of users’ contribution. This paper aims to examine users’ contribution in open innovation communities based on the social capital theory.Design/methodology/approachThe authors collected 474 valid responses from a survey and adopted structural equation modeling (SEM) to conduct data analysis.FindingsThe results indicated that social interaction, which includes informational and emotional interaction, has a significant effect on social capital, which in turn affects users’ contribution.Research limitations/implicationsThe results imply that companies need to facilitate users’ interactions and develop social capital to promote their contribution in open innovation communities.Originality/valueAlthough previous research has found the effect of individual motivations such as perceived benefits and behavioural control on innovation community users’ behaviour, it has seldom considered the effect of social capital embedded within the social relationship networking. This research tries to fill the gap and the results disclosed the mechanism underlying open innovation community users’ contribution.

Shaft stability evaluation (SSE) is one of the most crucial and important tasks in view of the role of vertical shaft in mining engineering, the accuracy of which determines the safety of on-site workers and the production rate of target mine largely. Existing artificial methods are limited to the amount of data and complex process of modeling as well as rare consideration of comprehensive evaluation model in this field. In this way, this paper introduces a high-efficient model that incorporating the unascertained measurement (UM) and multiple weights (the analysis hierarchy process, entropy and the criteria importance through intercriteria correlation) to meet the engineering requirements. Simultaneously, the main parameters, including surface subsidence velocity, cumulative surface subsidence(CSS), loose strata thickness(LST), the water level drop in aquifer (WLD), shaft wall thickness, construction methods and shaft wall types, and diameter ratio of shaft and shaft lining quality, are prepared to analyze the shaft stability. Linear and nonlinear membership functions are utilized to investigate the index correlation belonging to different risk levels. The stability class is determined through the index measurement vectors and classic classification criteria considering the individual index importance. The confusion matrix-based results show that the ensemble model with optimal structure has inspired performance in SSE with 100% accuracy. Furthermore, the shaft is sensitive to the factors CSS, LST and WLD using the sensitivity analysis. Additionally, some parameters associated with the shaft stability are investigated from Daye Iron mine (China) to validate the applicability of target model, the results of which are consistent to the on-site conditions perfectly. Findings reveal that the constructed model has great potential in assessing the shaft stability, which is beneficial to eliminate the risk of shaft failure in time.

In-plane uniaxial tension of AZ31 magnesium alloy sheet with non-basal texture has been conducted in order to demonstrate the effects of loading direction on the microstructure evolution and mechanical properties at ambient temperature. Loading axes are chosen to be along five directions distributed between rolling direction (RD) and transverse direction (TD), allowing various activities in involved slip and twinning modes to take place. As for twinning modes, electron backscattered diffraction observations confirm that the contribution of $${{\{ 10\overline{1}1\} }}$$ compression twinning is minimal to the plastic deformation of all deformed samples. By comparison, $${{\{ 10\overline{1}2\} }}$$ extension twinning (ET) not only serves as an important carrier on sustaining and accommodating plastic strain but also contributes to the emergence of TD-component texture with the progression of plastic strain. In terms of slip modes, analysis on Schmid factor demonstrates that the increasing tilted angle between loading direction and RD of sheet is unfavorable to the activation of basal slip, whereas it contributes to the activation of prismatic slip. These observations consequently explain the increasing tendency of 0.2% proof yield stress. Moreover, the activations of basal slip and $${{\{ 10\overline{1}2\} }}$$ ET collectively contribute to the concentration of two tilted basal poles toward normal direction. With increasing angle between loading direction and RD, the activations of basal slip and $${{\{ 10\overline{1}2\} }}$$ ET are gradually weakened. This leads to a weakening tendency about concentration of two tilted basal poles, a generally increasing tendency about Lankford value (r-value) and a generally decreasing tendency about strain-hardening exponent (n-value).

Flood events are typically triggered by extreme precipitation in rain-dominant basins. In this study, to better understand the genetic mechanisms and characteristics of floods, copula functions are used to analyze the response of flood events to extreme precipitation. The coincidence probabilities of the typical extreme flood and precipitation events are calculated; different return periods of their arbitrary combinations are calculated, whereas the dangerous domains for flood control under different return periods are identified; furthermore, flood risk analysis under different extreme precipitation scenarios is performed via their conditional exceedance probabilities. The Xitiaoxi catchment (XC) and Dongtiaoxi catchment (DC) in the Zhexi Region of the Taihu Basin are selected as the study area. The results show that in four scenarios with precipitation frequencies of 80%, 90%, 93.33%, and 95%, the probabilities of the dangerous flood are 9.72%, 10.57%, 10.86%, and 11.01% in the XC, respectively, and 5.91%, 6.31%, 6.44%, and 6.51% in the DC, respectively. This study provides a practical basis and guidance for the computation of rainstorm designs, management of flood control safety, and water resource scheduling in the Taihu Basin. HIGHLIGHTS This study focused on the flood risk in the main water source of Taihu Lake, i.e., the Zhexi Region, which had a direct and significant impact on the floods in the Taihu Basin.; Extreme hydrological and meteorological events were considered as the objects of this study. Their joint probability distribution and combined effects were directly related to the degree of flood risk.

PurposeThe purpose of this research is to draw on the elaboration likelihood model (ELM) to examine users' information adoption intention in online health communities (OHC).Design/methodology/approachThe authors collected 350 valid responses using a survey and conducted the moderated regression analysis to examine the research model.FindingsThe results indicated that users' information adoption intention is influenced by both central cues (argument quality) and peripheral cues (source credibility and emotional support). In addition, self-efficacy moderates the effect of both central cues and peripheral cues on information adoption intention.Originality/valuePrevious research has focused on the effect of individual motivations such as reciprocity and benefits on user behavior, and has seldom disclosed the influencing process of external factors on OHC users' behavioral decision. This research tries to fill the gap by adopting ELM to uncover the mechanism underlying OHC users' information adoption.

A novel and efficient deformation methodology, viz., hot-rolling–shearing–bending (HRSB), to introduce a large amount of $$\{ 10\bar {1}2\}$$ extension twins (ETs) and control the texture of the AZ31 magnesium alloy thin sheet was proposed. Microstructure and texture within various regions of the thin sheet fabricated by the HRSB method were investigated by means of electron back-scattered diffraction measurement. The experimental results indicated that using only single pass of HRSB, grains with c-axis//normal direction (ND) in as-received sheet are nearly twinned totally (about 91% volume fraction of $$\{ 10\bar {1}2\}$$ ET), leading to the formation of c-axis//rolling direction (RD) texture component and the disappearance of c-axis//ND texture component. As for the HRS sample which has suffered from rolling–shearing deformation, both a tensile stress component deriving from the shearing deformation and a compressive stress component resulting from the impediment effect of the mould structure are beneficial to activate $$\{ 10\bar {1}2\}$$ ET, the volume fraction of which is about 72%. With respect to the HRSB sample which has undergone rolling–shearing–bending deformation, the further increase in volume fraction of $$\{ 10\bar {1}2\}$$ ET might be mainly related to the resultant compressive stress of the tensile stress derived from the bending deformation and the compressive stress resulting from the impediment effect of mould structure. It would hinder the activation of $$\{ 10\bar {1}2\}$$ ET within twinned areas and promote the migration of existing boundaries of $$\{ 10\bar {1}2\}$$ ET into un-twinned areas.

In this work, we investigated the morphology, crystallization, and mechanical properties of the polyoxymethylene/thermoplastic polyamide elastomer (POM/TPAE) blends. It was found that POM and TPAE are partially compatible. By blending with TPAE, the toughness and low-temperature performance of POM can be improved significantly. However, there is a maximum value for the improvement of POM toughness, which is related to the amount of TPAE. We found that TPAE is dispersed in the POM matrix as spherical particles, and the particle size of these varies with the content of TPAE. Another interesting finding is that adding TPAE can change the crystalline properties of POM. For example, after adding TPAE, the crystallization particles of POM become smaller, part of the crystal area disappears, and the crystallization temperature decreases. All these results suggest that TPAE improves the toughness and low-temperature performance of POM by improving the crystallization, morphological structure, and morphology of the POM blends.

Online health communities (OHC) provide a platform for users to exchange health-related information and seek emotional support. However, users often lack the intention to share their knowledge, which may lead to the failure of OHC. Drawing on the social influence theory, this research examined OHC users’ sharing behaviour. The results indicated that users’ sharing intention is influenced by three social influence factors, which include subjective norm, social identity and group norm. In addition, social support and privacy concern have effects on these three social influence factors. The results imply that OHC need to leverage social influence in order to facilitate users’ sharing behaviour.

The hot deformation behavior and microstructure evolution of an Fe–30Cr–2Mo ultra-pure super ferritic stainless steel were investigated at the temperature range of 950–1150 °C and strain rate varying from 0.01 to 10 s−1. A strain compensated constitutive equation based on the Arrhenius-type model was established to predict the flow stress. The hot processing map based on the dynamic materials model was achieved to identify the optimum processing parameters. In addition, the features of microstructure evolution combined with the processing map were systematically investigated. The experimental results revealed that the flow stress increased with decreasing deformation temperature or increasing strain rate. Dynamic recovery was confirmed to be the predominant softening mechanism. The values of flow stress predicted by the strain compensated constitutive equation agreed well with the experimental values. The extent of dynamic recrystallization and recrystallized grain size increased with increasing deformation temperature or decreasing strain rate, and the continuous dynamic recrystallization was attributed to be the predominant mechanism of recrystallization during hot deformation. The optimum hot working parameters were determined to be the deformation temperature of 1070–1150 °C and strain rate of 0.1–1 s−1 with a peak power dissipation efficiency of 42%.

Polyoxymethylene/thermoplastic polyamide elastomer (POM/TPAE) blends were prepared through melt extrusion in an attempt to improve the toughness and electrical properties of POM. The TPAE used in the study had the permanent antistatic effect, and its brand was MV2080. Acrylonitrile-butadiene-styrene copolymer grafted maleic anhydride (ABS-g-MAH) was added while preparing the POM/TPAE blends to improve the compatibility between TPAE and POM. The effects of TPAE and ABS-g-MAH on the morphologies, melting crystallization, dynamic mechanical analysis, surface resistivity and mechanical properties were examined in detail with various techniques. It was found that after adding 15 phr MV2080 as the modifier, the distribution of MV2080 in the blends was presented as many continuous long strips, which can be called “antistatic networks.” When using ABS-g-MAH as a compatibilizer, the surface resistivity of the samples 5#, 6#, and 7# which all containing 15 phr MV2080 with the best antistatic properties reached 107 Ω, and the impact strength of the above samples was all increased by more than 66%.

In this study, we consider a multi-cell millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) system with a mixed analog-to-digital converter (mixed-ADC) and hybrid beamforming architecture, in which antenna selection is applied to achieve intelligent assignment of high- and low-resolution ADCs. Both exact and approximate closed-form expressions for the uplink achievable rate are derived in the case of maximum-ratio combining reception. The impacts on the achievable rate of user transmit power, number of radio frequency chains at a base station, ratio of high-resolution ADCs, number of propagation paths, and number of quantization bits are analyzed. It is shown that the user transmit power can be scaled down inversely proportional to the number of antennas at the base station. We propose an efficient power allocation scheme by solving a complementary geometric programming problem. In addition, the energy efficiency is investigated, and an optimal tradeoff between the achievable rate and power consumption is discussed. Our results will provide a useful reference for the study of mixed-ADC multi-cell mmWave massive MIMO systems with antenna selection.

Coordinated multipoint (CoMP) and massive multiple-input multiple-output (mMIMO) are two of promising technologies in future intelligent high-speed railway (HSR) communication systems, whose performance is fundamentally determined by the characteristics of cooperative mMIMO channels. This article proposes a dynamic three-dimensional (3-D) wideband geometry-based stochastic model (GBSM) for HSR cooperative mMIMO channels. The proposed GBSM employs a sphere model and two elliptic-cylinder models to describe common and uncommon clusters for different links, and integrates the dynamic cluster evolution in both time and array domains. Statistical properties of the cooperative mMIMO model are investigated, such as multi-link spatial cross-correlation function and sum rate capacity. A corresponding dynamic 3-D wideband simulation model for the HSR cooperative mMIMO channel is also proposed. Finally, numerical results of the statistical properties are analyzed, and the proposed model is validated by realistic HSR channel measurement data, in terms of dual-link spatial cross-correlation and channel capacity. This model is more practical and will be helpful for facilitating the design and performance evaluation of future intelligent HSR communication systems.

A simple, low-cost, and reliable strategy was developed to prepare SERS substrates with ultra-high sensitivity using laser-induced selective metallization of polymers combined with an improved galv...

Both multilayered (ML) and few-layered (FL) Ti3C2Tx nanosheets have been prepared through a typical etching and delaminating procedure. Various characterizations confirm that the dominant terminal groups on ML-Ti3C2Tx and FL-Ti3C2Tx are different, which have been assigned to O-related and hydroxyl groups, respectively. Such deviation of the dominant terminals results in the different physical and chemical performance and eventually makes the nanosheets have different potential applications. In particular, before coupling to Ag nanoparticles, ML-Ti3C2Tx can present stronger near-field enhancement effect; however, Ag/FL-Ti3C2Tx hybrid structure can confine stronger near-field due to the electron injection, which can be offered by the terminated hydroxyl groups.

Struvite crystallization has been regarded as a sustainable route to recover phosphorus from wastewaters. In this study, sodium alginate (SA) was chosen as model extracellular polymeric substances (EPS) to investigate its impact on struvite crystallization. The experimental results demonstrate that SA can remarkably influence struvite morphogenesis, resulting from the selective adsorption and binding of SA molecules onto the crystal faces with higher Mg content. SA concentration-dependent experiments show that SA significantly inhibits struvite growth, and the growth inhibition is caused by the adsorption of SA onto struvite surface, thus blocking the active growth sites. We also found that the elevation in Mg/P ratio or initial pH (pHi) can promote struvite growth, thus compensating the adverse effect of SA. Considering that SA is model EPS, our results provide a new insight into the role of EPS on struvite crystallization from wastewater. This will help to improve struvite crystallization technique.

A new robust adaptive fusion method for double-modality medical image PET/CT is proposed according to the Piella framework. The algorithm consists of the following three steps. Firstly, the registered PET and CT images are decomposed using the nonsubsampled contourlet transform (NSCT). Secondly, in order to highlight the lesions of the low-frequency image, low-frequency components are fused by pulse-coupled neural network (PCNN) that has a higher sensitivity to featured area with low intensities. With regard to high-frequency subbands, the Gauss random matrix is used for compression measurements, histogram distance between the every two corresponding subblocks of high coefficient is employed as match measure, and regional energy is used as activity measure. The fusion factor d is then calculated by using the match measure and the activity measure. The high-frequency measurement value is fused according to the fusion factor, and high-frequency fusion image is reconstructed by using the orthogonal matching pursuit algorithm of the high-frequency measurement after fusion. Thirdly, the final image is acquired through the NSCT inverse transformation of the low-frequency fusion image and the reconstructed high-frequency fusion image. To validate the proposed algorithm, four comparative experiments were performed: comparative experiment with other image fusion algorithms, comparison of different activity measures, different match measures, and PET/CT fusion results of lung cancer (20 groups). The experimental results showed that the proposed algorithm could better retain and show the lesion information, and is superior to other fusion algorithms based on both the subjective and objective evaluations.

Irregular coal pillars are often reserved in the upper coal seam in multiseam mining due to the limitation of geological conditions and mining methods. Diffused and transmitted stress in the pillars will form the stress concentrated areas in the lower coal seam and will increase the risk of rockburst. Based on the upper irregular pillars and fault encountered in the 7301 working face of the Zhaolou coal mine, this paper studies the evolution of stress and energy when the working face passed through the area affected by pillars. The adopted methods include numerical simulations and field monitoring. The change in stress concentration factor and stress gradient because of the mining activities in lower coal seam was analyzed by numerical simulation, indicating that the stress gradient reaches a peak when the working face is closed to the area under the edge and junction of pillars, which has the high risk of inducing rockburst. The sources’ location, variation rule of microseismic (MS) total energy and events, frequency spectrum distributions, and source parameters are discussed, respectively, based on the field monitoring data. The main conclusions were obtained as follows: (1) The total energy and event counts reach the peak when working face is close to the area under the edge and the junction of pillars. (2) The dominant frequency transfers from high frequency to low frequency, the stress drop reaches the peak value, the energy index decreases sharply, and the cumulative apparent volume increases sharply, which all are obvious precursory characteristics before rockburst.

The phase equilibria of the Mg-Gd-Ce system at 500 °C were investigated by means of the electron probe microanalysis (EPMA) and x-ray diffraction (XRD) on equilibrated alloys. The existence of the so-called normal tetragonal CeMg12(I) and long-range ordered CeMg12(II) was confirmed in the present work. The following five three-phase equilibria were well determined: (1) (Mg) + CeMg12(I) + Ce5Mg41, (2) (Mg) + Ce5Mg41 + GdMg5, (3) Ce5Mg41 + GdMg5 + (Ce,Gd)Mg3, (4) (Ce,Gd)Mg3 + GdMg2 + (Ce,Gd)Mg and (5) (Ce,Gd)Mg + (δCe) + (βCe). The solubility of Ce in GdMg5 and in GdMg2 was measured to be 7.8 and 8.7 at.% Ce, respectively. The solubility of Gd in CeMg12(I), in Ce5Mg41 and in (δCe) were measured to be 1.0, 4.6 and 2.4 at.% Gd, respectively. Two continuous series of solid solutions form between GdMg3 and CeMg3, and between GdMg and CeMg. The overall isothermal section at 500 °C was constructed based on the present data with a few extrapolations.

Bacteria are able to induce struvite precipitation, and modify struvite morphology, leading to the mineral with various growth habits. However, the relevant work involving the morphogenesis is limited, thereby obstructing our understanding of bacterially mediated struvite mineralization. Here, an actinomycete Microbacterium marinum sp. nov. H207 was chosen to study its effect on struvite morphology. A combination of bacterial mineralization and biomimetic mineralization techniques was adopted. The bacterial mineralization results showed that strain H207 could induce the formation of struvite with grouping structure (i.e., a small coffin-like crystal grown on a large trapezoid-like substrate crystal), and the overgrowth structure gradually disappeared, while the substrate crystal further evolved into coffin-like, and quadrangular tabular morphology with time. The biomimetic experiments with different organic components confirmed that the soluble macromolecules rich in electronegative carboxyl groups secreted by strain H207 dominate the formation of the struvite grouping. The time-course biomimetic experiments with supernatant testified that the increase in pH and NH4+ content promoted the evolution of crystal habits. Moreover, the evolution process of substrate crystal can be divided into two stages. At the first stage, the crystal grew along the crystallographic b axis. At the later stage, coupled dissolution–precipitation process occurred, and the crystals grew along the corners (i.e., [110] and [1-10] directions). In the case of dissolution, it was also found that the (00-1) face of substrate crystal preferentially dissolved, which results from the low initial phosphate content and high PO43− density on this face. As a result, present work can provide a deeper insight into bio-struvite mineralization.

Calcium supplement is the most commonly adopted treatment for osteoporosis but usually requires high dose and frequency. The modality of calcium supplement is therefore overlooked by current nanomedicine-based osteoporosis therapies without proper oral formulations. Herein, we proposed a tetracycline (Tc) modified and monostearin (MS) coated amorphous calcium carbonate (ACC) platform (TMA) as oral bone targeted and osteoporosis microenvironment (water/pH) responsive carrier for in situ calcium supplement. Moreover, current osteoporosis therapies also fall short of finding suitable molecular target and effective therapeutic regimen to further increase the therapeutic efficacy over available treatment means. As a result, the simvastatin (Sim) was loaded into TMA to construct drug delivery system (TMA/Sim) capable of synergistically activating the bone morphogenetic proteins (BMPs)-Smad pathway to provide a novel therapeutic regimen for osteoblast promotion mediated osteoporosis therapy. Our results revealed that optimized TMA showed high accessibility and oral availability with targeted drug delivery to bone tissue. Most importantly, benefit from the effective in situ calcium supplement and targeted Sim delivery, this therapeutic regime (TMA/Sim) achieved better synergetic effects than conventional combination strategies with promising osteoporosis reversion performance under low calcium dosage (1/10 of commercial calcium carbonate tablet) and significantly attenuated side effects.

The prediction of coal fusion characteristics and determination of slagging behaviour are of great significance to the operation of thermal power plants. The traditional method needs a long time to measure coal ash fusion temperatures (AFTs) by heating the coal ash cone. The purpose of this work is to predict the coal AFTs directly from coal rather than coal ash using Laser-Induced Breakdown Spectroscopy (LIBS). On the premise that ash content, volatile matter, fixed carbon and moisture are known on the air-dry base state, these four parameters are added into the model as generalized spectral (GS) variables to improve the accuracy of coal AFT prediction, in which the R2 of softening temperature (ST) and hemisphere temperature (HT) reached 0.9958 and 0.9856, the root-mean-square of cross-validation (RMSECV) reached 4.88 °C and 9.11 °C, and the root-mean-square of prediction (RMSEP) reached 8.15 °C and 11.3 °C, respectively. The trend relationships between the AFTs and the intensities (or ratio) of the spectral lines corresponding to individual elements of the LIBS spectrum were analysed. Then the variation trend of coal AFTs with specific element content (or ratio) is deduced qualitatively. We demonstrated that the model and scheme developed in this work can be applied in a real-time guiding role in the actual production process of the power plant.

The mechanical-property improvement of directionally-solidified Nickel-based single crystal (SC) superalloy with the single-direction magnetic fields is limited by their destructiveness on the dendritic microstructure. Here, the work present breaks through the bottleneck. It shows that the application of the cusp magnetic field (CMF) ensures that the dendrites are not destroyed. This feature embodies that the primary dendrite trunks arrange regularly and orderly, as well the secondary dendrite arms grow symmetrically. By contrast, both the unidirectional transverse and longitudinal magnetic field destroy the dendrite morphology, and there are a number of stray grains near the totally-remelted interface. The nondestructive effect is achieved mainly by the combined action of the thermoelectromagnetic force on the dendrites and thermoelectromagnetic convection in the melt during directional solidification. The investigation should contribute a new route for dramatically and effectively improving the crystal quality and mechanical properties of the directionally-solidified alloys.

The intelligent reflecting surface (IRS) is considered a core technology of next-generation mobile communication. It has significant advantages in enhancing network coverage, spectrum efficiency, energy efficiency, and deployment cost. Compared with the conventional massive multiple-input-multiple-output (MIMO) system, cell-free massive MIMO overcomes the limitation imposed by inter-cell interference in traditional cellular mobile networks and realizes coherent transmission centered on users. In this article, we consider a new application scenario for the IRS - an aerial IRS (AIRS)-aided cell-free massive MIMO system where multiple APs serve several users through an AIRS. The users are in a “shadow area” where we cannot provide good quality of service (QoS) due to the remote location and the shelter of tall buildings. Our goal is to optimize the power allocation and beamforming of each AP, the placement and reflection phase shift parameters of the AIRS to maximize the user's achievable rate. Firstly, we consider the optimization for fixed placement of the AIRS, where we propose a joint optimization strategy to maximize the achievable rate of the user. Then, we propose a fast optimal location search algorithm base on the path loss model to determine the optimal location of the AIRS and decrease the computational complexity. The simulation results show that the proposed methods can improve the performance for the achievable rate of the system. To the best of our knowledge, this article is the first to study the application scenario for the combination of IRS technology and a cell-free massive MIMO system.

Content-based medical image retrieval (CBMIR) systems attempt to search medical image database to narrow the semantic gap in medical image analysis. The efficacy of high-level medical information representation using features is a major challenge in CBMIR systems. Features play a vital role in the accuracy and speed of the search process. In this paper, we propose a deep convolutional neural network- (CNN-) based framework to learn concise feature vector for medical image retrieval. The medical images are decomposed into five components using empirical mode decomposition (EMD). The deep CNN is trained in a supervised way with multicomponent input, and the learned features are used to retrieve medical images. The IRMA dataset, containing 11,000 X-ray images, 116 classes, is used to validate the proposed method. We achieve a total IRMA error of 43.21 and a mean average precision of 0.86 for retrieval task and IRMA error of 68.48 and F1 measure of 0.66 on classification task, which is the best result compared with existing literature for this dataset.

The spiculation sign is one of the main signs to distinguish benign and malignant pulmonary nodules. In order to effectively extract the image feature of a pulmonary nodule for the spiculation sign distinguishment, a new spiculation sign recognition model is proposed based on the doctors’ diagnosis process of pulmonary nodules. A maximum density projection model is established to fuse the local three-dimensional information into the two-dimensional image. The complete boundary of a pulmonary nodule is extracted by the improved Snake model, which can take full advantage of the parallel calculation of the Spike Neural P Systems to build a new neural network structure. In this paper, our experiments show that the proposed algorithm can accurately extract the boundary of a pulmonary nodule and effectively improve the recognition rate of the spiculation sign.

Wind disturbance may significantly reduce the flight control performance of quadrotors when flying. In order to meet high performance flight control requirements, this paper presents a quadrotor anti-wind model (QAWM) and a flight control scheme for quadrotors. The QAWM takes the influence of aerodynamic effects on the propeller, gyroscopic effect and wind disturbance into account. The model can represent more flight states including not only hovering but also flight in windy conditions even maneuver flight. A cascade control scheme with an improved extended state observer (IESO) is adopted to decompose the quadrotor flight control problem into position control loop and attitude control loop. In the attitude control loop, the IESO is used to estimate the unmodeled dynamics, parameter uncertainties and external disturbances, as well as compensate the angular velocity control. In addition, the stability of IESO and the closed loop system are proved. Simulation and experimental results show the effectiveness of the nonlinear quadrotor model and control scheme, and the control scheme can effectively improve the flight performance of quadrotors under wind disturbance even maneuver flight.

Polysaccharides are a structurally diverse class of biomolecules with a wide variety of bioactivities. Natural polysaccharides isolated from plants and fungi are used as raw materials in food and pharmaceutical industries due to their therapeutic properties, non-toxicity, and negligible side effects, but many natural polysaccharides possess low bioactivities when compared to synthetic medicines due to their structure and physicochemical properties. Literature studies revealed that carboxymethylation of polysaccharides enhances the bioactivities and water solubility of native polysaccharides significantly, and provide structural diversity and even the addition of new bioactivities. This review article mainly focuses on the recent research on carboxymethylation of polysaccharides including preparation, characterization, and bioactivities. This article also throws light on future directions and scope to develop new carboxymethylated polysaccharide derivatives for many industries such as food processing, cosmetics, nutraceuticals, and pharmaceutical industry.

To improve the intrinsic electronic conductivity of Na3V2(PO4)2F3 (NVPF), zirconium (Zr) was introduced into the NVPF/C compound through a carbothermal reduction reaction with citric acid as the carbon source. The effects of Zr4+ doping on the crystal structure and morphology of the as-prepared materials were analyzed. Electrochemical and kinetic properties of the samples were investigated by galvanostatic charge-discharge, CV and EIS test. It is confirmed that moderate Zr4+ doping can improve the electrochemical performance of NVPF. Among all Na3V2-xZrx(PO4)2F3/C (x = 0, 0.01, 0.05, 0.1) samples, Na3V1·95Zr0·05(PO4)2F3/C shows the best rate and cycle performance. It exhibits the highest specific capacity of 121.8 and 110.3 mAh/g at 0.2 and 10 C, respectively, and maintains a capacity retention of approximately 83.6% after 1000 cycles at 5 C. The kinetic properties results show that the excellent electrochemical performance of Na3V1·95Zr0·05(PO4)2F3/C can be attributed to the increase in electronic conductivity and ion diffusion coefficient.

Neutron spectrum is essential to the safe operation of reactors. Traditional online neutron spectrum measurement methods still have room to improve accuracy for the application cases of wide energy range. From the application of artificial neural network (ANN) algorithm in spectrum unfolding, its accuracy is difficult to be improved for lacking of enough effective training data. In this paper, an adaptive deviation-resistant neutron spectrum unfolding method based on transfer learning was developed. The model of ANN was trained with thousands of neutron spectra generated with Monte Carlo transport calculation to construct a coarse-grained unfolded spectrum. In order to improve the accuracy of the unfolded spectrum, results of the previous ANN model combined with some specific eigenvalues of the current system were put into the dataset for training the deeper ANN model, and fine-grained unfolded spectrum could be achieved through the deeper ANN model. The method could realize accurate spectrum unfolding while maintaining universality, combined with detectors covering wide energy range, it could improve the accuracy of spectrum measurement methods for wide energy range. This method was verified with a fast neutron reactor BN-600. The mean square error (MSE), average relative deviation (ARD) and spectrum quality (Qs) were selected to evaluate the final results and they all demonstrated that the developed method was much more precise than traditional spectrum unfolding methods.

This letter investigates the problem of power distribution along with the word error probability (WEP) constraint for the orthogonal frequency division multiplexing based (OFDM) dual-function radar and communication sensor. First, we optimize the radar signal-to-noise ratio (SNR) with the constraints of the WEP requirement and total transmit power. Second, we propose an alternating direction sequential relaxation programming algorithm that involves solving a sequence of approximation convex version of the original nonconvex problem. Finally, simulation results are provided to evaluate the effect of different WEP requirements on the radar SNR, and a significant gain in the radar SNR can be achieved, compared to the average power allocation case.

Polyoxymethylene/thermoplastic polyether elastomer composites were prepared by using the chain extender based on styrene, methyl methacrylate and glycidyl methacrylate copolymer as the reaction compatibilizer. The composites were fabricated by melt extrusion, and the content of thermoplastic polyether elastomer varied from 0 to 25 phr, while the amount of the chain extender was 0.2, 0.4, and finally 0.6 phr at thermoplastic polyether elastomer content 15 phr. The reactive compatibilization and the properties of the blends were studied. It was found that the viscosity of the blends increased gradually, and the notch impact strength did not change significantly after the addition of chain extender, but the tensile modulus increased significantly.

Abstract Quantitative modelling of precipitation kinetics can play an important role in a computational material design framework where, for example, optimization of alloying can become more efficient if it is computationally driven. Precipitation hardening (PH) stainless steels is one example where precipitation strengthening is vital to achieve optimum properties. The Langer–Schwartz–Kampmann–Wagner (LSKW) approach for modelling of precipitation has shown good results for different alloy systems, but the specific models and assumptions applied are critical. In the present work, we thus apply two state-of-the-art LSKW tools to evaluate the different treatments of nucleation and growth. The precipitation modelling is assessed with respect to experimental results for Cu precipitation in PH stainless steels. The LSKW modelling is able to predict the precipitation during ageing in good quantitative agreement with experimental results if the nucleation model allows for nucleation of precipitates with a composition far from the equilibrium and if a composition-dependent interfacial energy is considered. The modelling can also accurately predict trends with respect to alloy composition and ageing temperature found in the experimental data. For materials design purposes, it is though proposed that the modelling is calibrated by measurements of precipitate composition and fraction in key experiments prior to application. Graphic abstract

This study demonstrated that as-synthesized nano Fe/Cu bimetals could achieve significant enhancement in the degradation of diclofenac (DCF), as compared to much slow removal of DCF by Cu(II) or zero valent iron nanoparticles (nZVI), respectively. Further observations on the evolution of O2 activation process by nano Fe/Cu bimetals was conducted stretching to the preparation phase (started by nZVI/Cu2+). Interesting breakpoints were observed with obvious sudden increase in the DCF degradation efficiency and decrease in solution pH, as the original nZVI just consumed up to Fe(II) and Cu(II) appeared again. It suggested that the four-electrons reaction of O2 and Cu-deposited nZVI would occur to generate water prior to the breakpoints, while Cu(0) and Fe(II) would play most important role in activation of O2 afterwards. Through the electron spin resonance (ESR) analysis and quenching experiments, OH was identified as the responsible reactive species. Further time-dependent quantifications in the cases of Cu(0)/Fe(II) systems were carried out. It was found that the OH accumulation was positively and linearly correlated with nCu dose, Fe(II) consumption, and Fe(II) dose, respectively. Since either Cu(0) or Fe(II) would be inefficient in activating oxygen to produce OH, a stage-evolution mechanism of O2 activated by nano Fe/Cu bimetals was proposed involving: (a) Rapid consumption of Fe(0) and release of Fe(II) based on the Cu-Fe galvanic corrosion, (b) adsorption and transformation of O2 to O22− at the nCu surface, and (c) Fe(II)-catalyzed activation of the adsorbed O22− to OH.

User contributions are crucial to the success of open source software (OSS) communities. As users conduct frequent interactions between each other, their contribution behaviour may receive the social influence from other members. Drawing on the social influence theory, this research examined user contributions in OSS communities. The results indicated that contribution intention is significantly affected by social identity, which includes cognitive, affective and evaluative identity. In addition, the researchers found that the subjective norm has a negative effect on contribution intention. The results imply that service providers need to enhance user identification with the community in order to facilitate their contribution in OSS communities.

This study demonstrated interesting ultrafast activation of molecular O2 by copper oxide (CuO) particles and very rapid elimination of aqueous 2,4-dichlorophenol (2,4-DCP) within reaction time of 30 s. Electron paramagnetic resonance (EPR) characterization indicated that OH, Cu3+, 1O2 and O2 − were generated in the CuO/O2 systems, wherein O2 − would be the main reactive species responsible for 2,4-DCP degradation. It was further found that the catalytic ability of CuO for O2 activation was highly size dependent and nano-CuO was far reactive than micro-CuO. H2 temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM) analyses revealed that both the quantity and the reactivity of the surface reaction sites (surface Cu+ and O2) could determine the catalytic ability of CuO affecting efficient Cu+-based molecular oxygen activation. Moreover, the O2 activation ability of CuO would depend on not only the dimension, but also crystalline factors, for example, the exposed facets.

Recently, lightweight and highly efficient electromagnetic interference (EMI) shielding composites are crucial but changing for the development of modern electronics and telecommunication. Here, a novel polyhedral Co/C particle embedded carbon nanofiber (CNF@Co/C) aerogels were synthesized via pyrolysis of bacterial cellulose wired zeolitic imidazolate frameworks-67 (ZIF-67) aerogel under argon. The flexible CNF@Co/C aerogels exhibit a high EMI shielding effectiveness (SE) is approaching 56.07 dB at a density of only 0.023 g cm−3 in the X band, and the average absorption coefficient is as high as 0.79, indicating 79% of electromagnetic (EM) waves are absorbed in shielding process. The remarkable performance results from the three-dimensional (3D) CNF-threaded porous structure with interconnected network and the magnetic Co/C particle strung by CNF, which contribute to a conduction loss and optimal impedance matching along with multiple polarization and strong magnetic loss. This work paves a promising way for the new generation of electronic device with lightweight and efficient EMI shielding.

The Mg-rich phase equilibria of the Mg-Y-Zn system at 500 °C were investigated with equilibrated alloys, by means of electron probe microanalysis and x-ray diffraction. A partial isothermal section of

Interface is the Achilles' heel in flexible electronics, where slipping, delamination, or cracking resulting from the intrinsic mechanical property mismatch of different materials might fail the device or cause degradation. Robust connections with strong interfacial strength and low interfacial impedance are highly desired in all kinds of flexible devices, especially when they require stretchability. Here, a new strategy of employing homogeneity is proposed to facilely achieve robust connection without introducing a third-party interlayer. The key to this strategy is implementing different functions in the same component materials, and in this work, this strategy is demonstrated by exploring the uniformity of carbon nanotube (CNT) in thermoplastic polyurethane (TPU) elastomer. Tuning the uniformity of CNT in TPU elastomer, two kinds of CNT-TPU composites (CTCs) are fabricated. They present contrasting properties of conductivity (281 folds), Young's modulus (7.1 folds), and strain sensitivity (15.7 folds) with the same weight fraction of CNT (15 wt %), and thus they can respectively act as strain sensor and interconnector in all-CNT-based stretchable strain monitoring electronics. The interlocking effect caused by spontaneous entanglement of surface polymer chains and the reconstruction of percolation network at the interface during drying confer the connection with robustness. The practical value of this strategy has been exemplified by the fabrication of a robust epidermis device via additive manufacturing. This epidermis device is patterned in a fractal motif for conformal contact and can sensitively monitor body motions and radial artery pulse.

The damage caused by marine fouling organisms to ships and underwater artificial equipment is becoming increasingly serious issue, and the prevention and control of marine biofouling has always been a research hotspot in marine coatings. Aiming at the problems of poor adhesion, long curing time and high curing temperature of low-surface energy marine antifouling coatings of organosilicon, a hydrophobic low-surface energy nano-SiO2/silicon acrylic resin nanocomposite coating was synthesized. The anticorrosive property of the composite coatings was analyzed by simulated seawater periodic immersion experiments. The gel permeation chromatography analysis showed that polydimethyl-siloxanes (PDMS) is involved in cross-linking reactions. The dynamic thermomechanical analysis indicated that the glass transition temperature of resin is 58 °C. The contact angle (CA) test showed that the CA of nanocomposite coating is 109.99°. All the detection results can support the excellent antifouling and anticorrosion performance of the low surface energy nanocomposite coatings.

Background: The calcium supplement is a clinically approved approach for osteoporosis therapy but usually requires a large dosage without targetability and with poor outcome. This modality is not fully explored in current osteoporosis therapy due to the lack of proper calcium supplement carrier. Methods: In this study, we constructed a tetracycline (Tc) modified and simvastatin (Sim) loaded phospholipid-amorphous calcium carbonate (ACC) hybrid nanoparticle (Tc/ACC/Sim). Results: The resulted Tc/ACC/Sim was able to enhance its accumulation at the osteoporosis site. Most importantly, the combination of calcium supplement and Sim offered synergetic osteoblast promotion therapy of osteoporosis with advanced performance than non-targeted system or mono therapy. Conclusion: This platform provides an alternative approach to stimulate bone formation by synergetic promotion of osteoblast differentiation using calcium supplement and Sim.

PurposeThe purpose of this research is to examine the effect of information privacy concern on users' social shopping intention.Design/methodology/approachBased on the 340 valid responses collected from a survey, structural equation modeling (SEM) was employed to examine the research model.FindingsThe results indicated that while disposition to privacy positively affects privacy concern, both reputation and laws negatively affect privacy concern, which in turn decreases social shopping intention. In addition, trust partially mediates the effect of privacy concern on social shopping intention.Research limitations/implicationsThe results imply that social commerce companies need to mitigate users' privacy concern in order to facilitate their shopping behavior.Originality/valueThis research disclosed that privacy concern receives a tripartite influence from users (disposition to privacy), platforms (reputation) and governments (laws). The results help us gain a complete understanding of information privacy concern mitigation in social shopping.

This paper presents an integrated research scheme for vector deflection and energy extraction in a gas plasma jet under Magneto-Hydrodynamic (MHD) control. A MHD-controlled thrust-vector test rig was used to conduct the experimental research. A gas plasma was obtained by injecting ionization seeds of Cs2CO3 into the combustion chamber via artificially forced ionization. The effects of the gas temperature and ionization seed mass fraction on the plasma jet deflection and energy extraction were experimentally verified under an applied magnetic field. The experimental results were analyzed theoretically. The results showed that the deflection amplitude of the gas plasma jet and the extracted voltage signal intensity increased with increasing gas temperature and the ionization seed mass fraction. The extracted dynamic voltage signals proved that the ionization seeds of Cs2CO3 induced gas ionization at 1173 K. The experiment verified that it is feasible to simultaneously achieve jet deflection and extract energy under the action of an external magnetic field.

Soft actuation materials are highly desirable in flexible electronics, soft robotics, etc. However, traditional bilayered actuators usually suffer from poor mechanical properties as well as deterio...

PurposeFacility structures in liquefied natural gas (LNG) plants require tremendous amounts of scaffolding to facilitate relevant industrial operation and maintenance. As such, the productivity of scaffolding operations in turnaround maintenance (TAM) has attracted much attention in recent years. In addition, health and safety issues have been recognised as a key contributor along with productivity improvement in the LNG industry. This study aims to integrate work posture analysis into value stream mapping to achieve an optimised and balanced improvement in both productivity and health and safety.Design/methodology/approachA case study approach is adopted to integrate lean and work posture analysis in a TAM site. The lean improvement is conducted through value stream mapping, and the work posture analysis is conducted through the Ovako Working Posture Analysis System method. A three-step optimisation strategy is then developed for achieving optimised performance in waste reduction and work posture improvement.FindingsIt is found that the implementation of value stream mapping can help eliminate waste in the installation process, therefore eliminating potential health and safety risks. However, health and safety of onsite workers does not always improve as lean implementation intensifies. There is an optimised erection schedule that has the lowest health and safety risk within a waste reduction target.Originality/valueIn contradiction to previous studies, which rely on qualitative assessment to identify the a positive correlation between lean and health and safety, this study reveals the distinct difference between lean attributes and health and safety attributes through a quantitative assessment and is more readily to be implemented at the site level for simultaneous improvement in lean and health and safety.