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Surface modification of different functional molecules onto NaREF4 (RE = rare earth) upconversion nanoparticles (UCNPs) impart their multiple functionalities. Functional molecules can be loaded onto NaREF4 UCNPs through the formation of coordination bonds between the surface-exposed RE3+ ions and the appropriate chemical groups of functional molecules. The density of surface RE3+ ions directly determines the loading efficiency of NaREF4 UCNPs. However, NaREF4 is a binary cation system, rendering the surface-distributed Na+ and RE3+ ions remains a mystery. Here, we develop an effective strategy to significantly enhance the density of surface RE3+ ions, thus maximizing the loading capacity of NaREF4 UCNPs. This strategy is based on a heterovalent cation exchange (HCE) reaction in the surface region in which Na+ ions are replaced by RE3+ ions. The density of surface ligands enhances from 3.6 to 8.8 molecules/nm2 after reaction, suggesting that the loading efficiency increases by approximately 150%. Benefiting from the improved loading capacity, we demonstrate such surface-RE-rich nanoparticles have the ability to offer higher colloidal stability and more desirable photodynamic therapy (PDT) efficacy. This work not only advances our understanding of cation exchange reactions in RE-based nanoparticles, but also provides significant value for considerable applications such as sensing, bioimaging, and therapy.

Purpose In this research, the highly dense bulk Cu-5Sn alloy specimens were fabricated using selective laser melting (SLM). This study aims to establish the relationship between laser power (LP), scanning speed (SS) and hatch space (HS) with surface roughness (Ra) and density. To obtain Cu-5Sn alloy formed parts with high strength and low surface roughness. The microstructure and mechanical properties of SLMed Cu-5Sn were investigated. Design/methodology/approach The relative density (RD) was optimized using the response surface method (RSM) and analysis of variance. First, the Ra of SLMed formed specimens was studied to optimize the forming process parameters with a good surface. Then, the dense specimens were studied by ANOVA and the RSM to obtain dense specimens for mechanical property analysis. Findings Dense specimens were obtained by RSM and ANOVA. The tensile properties were compared with the casted specimens. The yield and ultimate strengths increased from 71 and 131 MPa for the cast specimens to 334 and 489 MPa for the SLMed specimens, respectively. The ductility increased significantly from 11% to 23%, due to the refined microstructure of the SLMed specimens, as well as the formation of many twin crystals. Originality/value The Ra, RD and mechanical properties of SLM specimens Cu-5Sn were systematically studied, and the influencing factors were analyzed together. This study provides a theoretical and practical example to improve the surface quality and RD.

The provisional prosthesis is a prerequisite for prosthodontic rehabilitation. The purpose of this technique was to register facial and intraoral scans predictably. A 3D virtual patient was created through facial scans, intraoral scans, digital face-bow transfer, and digital cross-articulation technique. This virtual patient allowed predictable positioning of intraoral scans to a virtual articulator by using digital face-bow transfer. The resulting virtual patient facilitated the design of definitive prostheses following a facially generated treatment planning principle. In addition, the virtual articulator was used to improve occlusal design on the definitive prostheses and reduce the need for intraoral adjustment.

This technical report describes a workflow to fabricate an implant overdenture via digital duplication of an interim complete removable dental prosthesis and additive manufacturing (3D printing). An edentulous patient was provided with an interim maxillary denture after implant placement. After 4 months of healing, the existing interim denture was scanned, duplicated via 3D printing, and used to make the final impression, record the maxillomandibular interocclusal relationship, and transfer the esthetic information to the definitive implant overdenture. The framework of the implant overdenture was digitally designed and manufactured using a direct metal printing (DMP) system. This digital duplication workflow facilitated the implant overdenture fabrication with favorable clinical outcomes.

PURPOSE To compare the dimensional accuracy of 3D-printed mandibular complete dentures with different build orientations. MATERIAL AND METHODS A mandibular complete denture was digitized as a virtual reference file. The reference file was 3D-printed at the 0°, 45°, and 90° build orientations with a MultiJet 3D printer (Projet MJP 3600 Dental, 3D systems, Rock Hill, SC). A total of 27 complete dentures were 3D-printed with 9 samples for each orientation. All printed dentures were digitized and separated into teeth, denture extension and intaglio test surfaces. The dimensional accuracy (in root mean square, RMS) was evaluated by comparing whole denture and 3 test surfaces with the reference file. One-way analysis of variance (ANOVA) and a Post-Hoc all pairs Bonferroni test were used to determine statistical differences (α = 0.05). RESULTS For the dimensional accuracy on whole denture, the 45° build orientation group showed the smallest RMS (0.170 ± 0.043 mm) than those of the 0° build orientation group (0.185 ± 0.060 mm, p < 0.001) and 90° build orientation group (0.183 ± 0.044 mm, p < 0.001). For the dimensional accuracy on the teeth, denture extension and intaglio test surfaces, the 45° build orientation group also show the smallest RMS values (0.140 ± 0.044 mm at teeth surface, 0.176 ± 0.058 mm at denture extension and 0.207 ± 0.006 mm at intaglio surface). The 0°and 90° build orientation groups had similar accuracy at the teeth (0.149 ± 0.056 mm versus 0.154 ± 0.056 mm, p = 0.164) and denture extension surfaces (0.200 ±0.025 mm vs 0.196 ± 0.013 mm, p = 1.000). However, 0° build orientation group (0.228 ± 0.010 mm) has significantly higher RMS values then those of 90° build orientation group (0.218 ± 0.057 mm) in the intaglio surface (p = 0.032). The teeth surfaces were most accurate in each build orientation groups, while the intaglio surfaces were least accurate. CONCLUSIONS The build orientation affected the dimensional accuracy of 3D-printed mandibular complete dentures, and the 45° build orientation resulted in the most accurate 3D-printed denture from a MultiJet 3D printer.

The parameter values of complex media can be uncertain in reality and uncertainty quantification (UQ) in the simulation of wave propagation is essential. In this paper, an efficient surrogate model...

A tunable photonic microwave frequency up-conversion scheme using opto-electronic oscillator (OEO) based on a monolithic integrated three-section laser without any electro-optic modulator (EOM) or filter is proposed. By adjusting the monolithic integrated three-section laser to operate in the period-one (P1) dynamical state, the signal carrier frequency up-converted from the intermediate frequency (IF) to the frequency at the difference and the summation between the oscillation frequency of OEO and IF can be realized. The tunability of the up-converted frequency can also be greatly guaranteed just by altering the control currents of the monolithic integrated three-section laser induced P1 frequency. In this paper, an IF of 2 GHz with 10 Msymbol/s 16-QAM signals is successfully up-converted to 16 GHz and 20 GHz simultaneously. The up-converted frequencies can be tuned from 16 GHz/20 GHz to 19 GHz/23 GHz, and the error vector magnitudes (EVMs) of all those up-converted signals satisfy the limitation in satellite communication.

To extend the modeling area with artificial neural networks (ANNs) from finite periodic arrays to thinned arrays, where spacings between adjacent elements are crucial for array performance, an efficient model is proposed in this letter. Considering the spacings, a novel hidden node interconnection-radial basis function neural network (HNI–RBFNN) is developed to map the relationship between the array electromagnetic (EM) responses and the element ones. The element EM responses are obtained with the traditional RBFNN only involving the element geometry, while the connected weights of hidden layer nodes are determined by mutual coupling and array environment with the HNI scheme. A numerical example of the thinned phased array is used to evaluate the validity of the proposed model.

In this paper, the governing equation of chloride diffusion in reinforced concrete square piles is presented. The deterioration process of a pile caused by chloride-induced reinforcement corrosion ...

The widespread use of smartphones has brought great convenience to our daily lives, while at the same time we have been increasingly exposed to security threats. Keystroke security is essential to user privacy protection. In this paper, we present GazeRevealer, a novel side-channel based keystroke inference framework to infer sensitive inputs on smartphone from video recordings of victim's eye patterns captured from smartphone front camera. We observe that eye movements typically follow the keystrokes typing on the number-only soft keyboard during password input. By exploiting eye movement patterns, we are able to infer the passwords being entered. We propose a novel algorithm to extract sensitive eye images from video streams, and classify these images with Support Vector Classification. We also propose a novel classification enhancement algorithm to further improve classification accuracy. Compared with prior keystroke detection approaches, GazeRevealer does not require any external auxiliary devices, and it only relies on smartphone front camera. We evaluate the performance of GazeRevealer on several smartphones under different real-life usage scenarios. The results show that GazeRevealer achieves an inference rate of 77.89 percent for single key number and an inference rate of 84.38 percent for 6-digit password in the ideal case.

Carboxymethyl cellulose (CMC)/pPoly-N-isopropylacrylamide (PNIPAM) hydrogels were prepared using nanoclay as physical cross-linker by UV irradiation. PNIPAM/CMC hydrogels exhibit 3D network structures with high porosity. PNIPAM/CMC hydrogels exhibit not only high water absorption capacity, but also temperature, pH and salt mutiple-responsive swelling performance. Besides, they exhibit reversible swelling behavior in alternate de-ionized water and NaCl solution. Moreover, the fabricated PNIPAM/CMC hydrogels display great compression mechanical property. Then, tetracycline hydrochloride (TCH) was loaded into the PNIPAM/CMC hydrogels to endow their antibacterial ability. TCH loaded PNIPAM/CMC hydrogels exhibit excellent antibacterial activity against E. coli and B. subtilis and good biocompatibility. Thus, the PNIPAM/CMC composite hydrogels with triple stimuli-responsive swelling performances reported herein have great potentials in many biomedical applications.

For wide-angle scanning phased arrays, the efficiency of active elements is deteriorated with the increase of mutual impedance. This article demonstrates an effective strategy to control the mutual impedance among array elements by canceling the major coupling effect. The implemented wide-angle impedance matching (WAIM) of a wideband phased array verifies the validity of the proposed strategy. For the array element, to obtain wide-angle radiation and wideband characteristic, parallel slots with unequal lengths are deliberately etched on a low-profile substrate integrated cavity (SIC). The mutual impedance between two arbitrary elements is remarkably controlled and compensated by canceling the major coupling effect, which is realized by etching symmetrical slots and loading periodical loops within each element. With the controlled mutual impedance, the proposed array possesses excellent wide-angle scanning performance. Both the simulated and measured results indicate that the designed array steers its main beam from −70° to +70° in the xoz azimuth plane in a broad frequency range from 8.0 to 9.5 GHz. The active $S$ -parameter of each element remains lower than −10 dB in the operating band while the array scans. Due to the implemented WAIM, the total efficiency of the array exceeds 90% during the scan and the fluctuation of realized gain is less than 3 dB.

The main issue in incremental nonnegative matrix factorization (INMF) is how to update base matrix and coefficient matrix. The re-training scheme(RT-NMF) and the scheme proposed by Bucak and Gunsel(BG-INMF) are two common methods. However, both of them have problems in balancing root mean square error(RMSE) and time cost when incremental samples appear in a batch form. In this paper, a three-stage method(3S-INMF) is proposed to derive a good balance between RMSE and time cost. In the first stage, only the coefficient matrix of incremental samples is updated while the base matrix and the coefficient matrix of old samples are fixed. If the RMSE does not meet the required precision after this stage, the second stage, i.e. BG-INMF, is carried out. In the second stage, the base matrix and the coefficient matrix of incremental samples are updated alternatively while the coefficient matrix of old samples is fixed. If the RMSE still does not meet with the required precision after BG-INMF, the coefficient matrix of old samples will be updated in the third stage while the base matrix and the coefficient matrix of incremental samples are fixed. In the three consecutive stages, the initial values of base matrix and coefficient matrix in each stage are the corresponding output values in the previous stage. In addition, extensive experiments on the three popular datasets show that 3S-INMF obtains the best balance between RMSE and time cost compared with RT-NMF and BG-INMF. Furthermore, the 3S-INMF is extended to graph nonnegative matrix factorization(GNMF) and kernel nonnegative matrix factorization(KNMF), which also has a superior performance examined by further experiments.

In order to satisfy the requirement of precise pin-point landing mission in Mars exploration, this paper proposes an innovative visual navigation algorithm based on feature lines extraction and matching to estimate the attitude and position of the lander during descent phase. Currently, common navigation landmarks are feature points and craters. But, the number of feature points extracted from landing image is so large that the image process is complex and time-consuming, and they do not usually have absolute coordinate information to absolute navigation. Meanwhile, crater is matched difficultly. Hence, ridges, fissures and other surface textures similar to lines are most common visual features of Mars and can be used as navigation landmarks for visual absolute and relative navigation. Firstly, that feature lines matching based on the EDLine algorithm remains invariant to scaling, rotation, and illumination, etc. provides the basis for visual navigation by using feature line. Secondly, feature lines selected as navigation landmarks can be used to absolute navigation and relative navigation respectively, which can implement integrated navigation. In this paper, a novel integrated visual navigation has been designed to finish the precise pin-point landing and overcome the accumulated errors of relative navigation and the limited application range of absolute navigation. Experimental simulation results show that the integrated navigation algorithm solves the limitation of single navigation mode and improves the effectiveness and stability of the algorithm.

A dual-module machine learning scheme is proposed to reconstruct inhomogeneous scatterers with high contrasts and large electrical dimensions. The first nonlinear mapping module (NMM) is an extreme learning machine (ELM), which is used to convert the measured scattered fields at the receiver arrays into the preliminary images of the scatterers. The second image-enhancing module (IEM) is a convolutional neural network (CNN), which is used to refine further the images from the NMM to obtain high-accuracy pixel-based model parameter distribution in the inversion domain. Compared with the traditional approximate methods such as backpropagation, the NMM-IEM machine learning can produce the preliminary image with a much higher accuracy but the unknown weight matrices of the ELM are only solved once during training. Hence, the IEM connected to the NMM has a simple architecture and can be trained at a rather low cost. The performance of the proposed dual-module NMM-IEM scheme and the conventional variational Born iterative method is compared in terms of inversion of scatterers with different electrical sizes and contrasts. Meanwhile, the NMM-IEM is also assessed for the inversion of scatterers with high contrasts and large electrical dimensions and experimental data. Finally, the NMM-IEM is compared with the CNNs used in the previous works.

To make metasurface design faster and more convenient, a new inverse extreme learning machine (ELM) is proposed in this letter. Compared with the traditional forward model based on artificial neural networks, the proposed inverse ELM uses a small number of training samples to meet the modeling standard, and it directly obtains the satisfying geometry without an optimization process. Meanwhile, to enhance the modeling performance, the data classification technique and a cascade of two ELMs are contained in the tailored scheme, where the second ELM is applied to error correction. A numerical example of an interdigital resonator metasurface is employed to verify the effectiveness and efficiency of the proposed model.

Liquid cooling systems in data centers have been attracting more attentions due to its better cooling capability and less energy consumption. In order to propose an effective optimization method for the operation of indirect liquid cooling systems, this paper first constructs an experiment platform and applies the heat current method to build the global heat transfer constraints of the whole system. Particularly, the thermal conductance of each heat exchanger under different working conditions is predicted by the Artificial Neural Networks (ANN) trained by the historical data. On this basis, combining the heat transfer and fluid flow constraints together with the Lagrange multiplier method builds the optimization model with the objective of minimum pumping power consumption (PPC), solving which by the solution strategy designed obtains the optimal frequencies of the variable frequency pumps (VFPs). Operating with the optimal and other feasible operating conditions validates the optimization model. Meanwhile, the experiments with variable heat loads and flow resistances provide some guidelines for the optimal system operation. For instance, to address heat load increase of a branch, it needs to increase the frequencies of the VFPs, not only the corresponding hot loop but also the whole cold loop.

This communication presents an artificial magnetic conductor (AMC) structure-loaded phased array with broadband low-RCS and wide-angle scanning performance. A substrate integrated with the cavity-backed antenna with wide beamwidth and decoupling cavity is used as the basic array element to increase the field-of-view scanning range of arrays. Meanwhile, a checkerboard-shaped AMC structure with a broadband region of 180° (±37°) phase difference is designed and loaded around the array to reduce its RCS in and out of the band. This communication is validated through measurements that matched well with simulations. The proposed array operates at 10.8 GHz and provides a wide scanning region from −70° to +70° in the H-plane with particularly small gain fluctuation (±1.5 dB). Moreover, the backscattering of the proposed array can be reduced to −6 dB for both TE and TM polarizations, covering the $X$ -, Ku -, and $K$ -bands. The proposed approach has the potential application in smart skin designs due to its low profile, powerful scanning ability, and broadband RCS reduction.

A solvothermal assisted ethylene glycol reduction method is a common technology for Pt/C catalysts preparation. Here, the coordination mechanism of the Pt-containing species is deeply studied by innovatively adopting the ultraviolet-visible spectroscopy technology and H+ concentration detector. Moreover, the amount of NaOH that effectively coordinates Pt4+ has been tentatively qualified and the heating parameters during the preparation process of Pt/C have also been optimized. As investigated, the optimized 20-(1/22)-140-2 Pt/C (20 wt%Pt; m(Pt):m(NaOH)=1/22; heating temperature: 140°C, heating time: 2 h) exhibits higher electrocatalytic activity towards oxygen reduction reaction (ORR) than the commercial 20 wt% Pt/C (E-TEK) in acidic media. This work provides a theoretical reserve and technical accumulation for industrialized mass production of highly efficient Pt/C catalysts for ORR in proton exchange membrane fuel cells.

The use of cross-polarized auxiliary waves in the design procedure of the passive lossless metasurface has been reported as an effective approach to improve its performance. However, the design with only one auxiliary wave leads to low efficiency of an impenetrable metasurface in general when the incident and reflected waves interact with each other. This communication presents two auxiliary waves to design high-efficiency metasurfaces for arbitrary beam control. Besides the cross-polarized auxiliary wave, the copolarized auxiliary wave is proposed to design metasurfaces with a scalar impedance for beam control. Moreover, auxiliary waves are expanded into Fourier series in the procedure and their coefficients can be effectively determined with a numerical optimization method. Some instances are provided and the numerical results show that the designed metasurfaces effectively can control beams. The comparison between the designed metasurface and the conventional phase-gradient one is also provided.

For planetary landing missions, accurate surface relative state knowledge to safely land near science targets is required. However, the lack of on-board map poses a technical challenge in the process of implementing such a navigation system. Moreover, traditional feature point observations are not sufficient for guaranteeing robust performance of the algorithm under challenging environmental conditions like texture-less terrain. This paper presents a novel visual navigation scheme based on curve matching for planetary landing in unknown environments. An analytical measurement model, which contains the lander's current and previous states, is derived by using curve matches in descent images for the first time. The derived measurement model and the state information sensed by inertial measurement unit are integrated in unscented Kalman filter algorithm. Also, the observability of the proposed navigation system is analyzed. In particularly, the Fisher matrix is used to evaluate the navigation performance. It is shown that the superior accuracy of the proposed method is obtained compared to point-based approaches. Simulation results demonstrate the effectiveness and high accuracy of the proposed navigation method.

Inertial Confinement Fusion (ICF) is an effective way to achieve nuclear fusion. In ICF, boron carbide ceramics are a crucial material to prepare targets due to its high neutron capture section, high hardness, and thermal stability. A common way to prepare boron carbide is the precursor transformation method, which can overcome the difficulty in the shaping of ceramics. Decaborane and olefins are reaction materials to prepare the precursor. However, the mechanism of the reaction is not clear now, and few studies on computational chemistry have been published in this area. In this research, the semi-empirical method of quantum mechanics and Molecular Dynamics in Hyperchem8.0 were used to optimize molecules in geometry. Formation enthalpy, bond energy, bond length and angle were calculated to explain experimental patterns. The optimized data is consistent with some typical phenomena in hydroboration and ring-opening metathesis polymerization. It demonstrates that those computational methods in Hyperchem8.0 can be applied to interpret and predict relevant reactions. In addition, this explanation provides a theoretical foundation for future synthesis on polyborane precursor.

One patch antenna with dual-band dual-mode (DMDB) characteristic based on mushroom structure is designed and analysed in this study. The antenna operates at two modes: the bidirectional mode with endfire radiation patterns and the directional mode with broadside radiation patterns. The equivalent circuit, dispersion diagrams, field distributions, reflection coefficients and radiation patterns are given for confirming the working principle. Compared with the former DMDB antennas, array antenna could be designed to realise gain enhancement for both the two modes. Both element and 1 × 2 array antenna prototypes were fabricated for verification. The measured results show that the two modes resonant at about 9.8 and 11.95 GHz, respectively. Comparing with the element, gain enhancement of about 2.8 and 2.1 dB are realised by the array for the endfire and broadside modes, respectively. With pattern diversity and array realisation, this antenna type owns potential application value in wireless communication systems.

The moving packed bed is commonly used for cooling high-temperature solid granules. Its effective and concise modelling is important for reducing the complexity of system analyses. This study defines the inlet temperature-based thermal resistance of solid granule cooling processes considering the porosity of the packed layer and constructs a heat current model of a practical moving packed bed. The corresponding governing equations are established by applying the Kirchhoff’s law in circuitous philosophy to reflect the overall heat transfer law in the entire moving packed bed with a low computational complexity. On this basis, the cooling process in a cement grate cooler is studied and the results simulated by the proposed model agree with those obtained using the finite difference method and experimental data. Meanwhile, the distribution of heat transfer rates in the cement grate cooler shows that the first stage, the following four stages, and the last four stages undertake 47.87%, 48.49%, and 3.93% of the total heat load, respectively. Moreover, the inlet temperature-based thermal resistance in the last four cooling stages accounts for 70.98% of the total thermal resistance, which can guide improvements in the cooling performance.

In this letter, a microstrip patch hybrid mode technique is introduced to design a 2-D wide-angle scanning planar phased array. The proposed element consists of a circular patch and four rectangular parasitic patches distributed around the circular patch. In order to obtain wider radiation beamwidth (BW) in two orthogonal azimuth planes, the TM11 mode of the circular patch and the zeroth-order resonant mode of the parasitic rectangular patches are separately excited. Experimental results show that the proposed element can obtain 3 dB BW more than 156° in the two orthogonal azimuth planes. Moreover, an 8 × 8 planar phased array formed by this element can realize wide-angle scanning in a range of about ±65° in the two orthogonal azimuth planes. In the above scanning range, the sidelobe levels of the phased array are always less than −7.8 dB, the scanning gain fluctuation is less than ±1.73 dB, and the main polarizations on the two orthogonal planes are both θ -polarized. In addition, the phased array has a simple structure, a low profile, and convenient fabrication.

To alleviate the nonuniform error distribution and slow convergence caused by the uncertainty of sample selection in the training process of artificial neural networks, a semisupervised radial basis function neural network (SS-RBFNN) model with a new sampling strategy is proposed for parametric modeling of microwave components in this article. After evaluating the current training performance, the new sampling strategy selects suitable training samples to ensure each subregion of the whole sampling region with the same level of training and testing accuracy. Meanwhile, the proposed SS-RBFNN simplifies the modeling process to further enhance the modeling accuracy and efficiency. Two numerical examples of a slow-wave defected ground structure dual-band bandpass filter and a microstrip-to-microstrip vertical transition are employed to verify the effectiveness of the proposed model.

This communication presents a novel compact broadband circularly polarized (CP) implantable patch antenna for biomedical applications in 2.4 GHz industrial, scientific, and medical (ISM) band. By employing slots on the patch plane and shorting method, the whole size (including the superstrate) of the designed antenna can be enormously reduced to $9.8\times 9.8\times1.27$ mm3, which is equivalent to $0.0784\lambda _{0}\times 0.0784\lambda _ {0}\times 0.0102\lambda _ {0}$ ( $\lambda _ {0}$ is the free-space wavelength at 2.4 GHz). Under the premise of keeping a slotless ground, not only a good size reduction is realized but also the impedance bandwidth and the axial ratio (AR) bandwidth are greatly improved. A simulated −10 dB impedance bandwidth of 21.5% with a 3 dB AR bandwidth of 15.8% is acquired in a skin phantom. The antenna also exhibits good robustness to different thicknesses of biocompatible coating. The influence of different body phantoms is discussed to evaluate the sensitivity of the proposed antenna. The experiments are carried out in both skin-mimicking gel and pork, and the respective measured impedance bandwidths are 25.9% and 25.7%. The CP purity is experimentally validated by comparing the communication link levels in two orthogonal polarization directions. The maximum specific absorption rate (SAR) value satisfies the IEEE standard safety guidelines.

Protein N-glycosylation plays crucial roles in many biological processes and has close association with the occurrence and development of various cancers. Therefore, it is necessary to analyze the abnormal changes of N-glycopeptides in complex biological samples for biomarker discovery. However, due to their low abundance and poor ionization, N-glycopeptides identification in complex samples by mass spectrometry (MS) is still a challenging task. In this work, a novel magnetic hydrophilic material was prepared by serial functionalization of ultra-thin two-dimensional molybdenum disulfide with Fe3O4 nanoparticles, gold nanowire and glutathione (MoS2–Fe3O4–Au/NWs-GSH) for efficient N-glycopeptides enrichment. The advantage of using the new nanocomposite is threefold. First, the introduction of magnetic Fe3O4 nanoparticles efficiently simplifies the enrichment process. Second, the gold nanowire modification enlarges the surface area of the nanocomposites to facilitate interaction with N-glycopeptides. Third, the employment of highly hydrophilic glutathione leads to specific HILIC-based retention of N-glycopeptides. Low femtomolar detection sensitivity and 1:1000 enrichment selectivity can be achieved using MoS2–Fe3O4–Au/NWs-GSH enrichment and bio-mass spectrometry analysis. Successful applications in human urine exosome and serum proteins were demonstrated by the enrichment and identification of 1250 and 489 N-glycopeptides, respectively. This remarkable data set of N-glycoproteome indicates the application potential of the novel nanocomposites for N-glycopeptides enrichment in complex biological samples and for related glycoproteome studies.

Smart contracts allow verifiable operations to be executed in blockchains, bringing new possibilities for trust establishment in trustless scenarios. However, smart contracts are cumbersome when used as security mechanisms in security scenarios due to two reasons: they have limited power and are inert to changes. In order to mitigate the two problems of employed smart contracts, we propose LSC, a framework for online auto-update smart contracts in blockchain-based log systems, to enable self-adaptive log anomaly detection via smart contracts. Time-varying log anomaly detection patterns are extracted by self-adaptive machine learning log anomaly analysis and are continuously fed to the contracts. The framework allows smart contracts to be automatically updated to express the patterns in low-cost ways. The anomaly detection strategies for audit log systems are shared and collaboratively enforced amongst network nodes to defend against targeted detection evasion. We provide a plain prototype as a proof of the feasibility and efficiency of LSC in log systems.

The ‘8.12’ Tianjin Port fire and explosion are an extraordinarily major accident that involved hazardous chemicals, resulting in 165 fatalities, 798 injuries, and a direct economic loss of 6.866 bi...

Soil materials can exhibit strongly dispersive properties in the operating frequency range of a physical system, and the uncertain parameters of the dispersive materials introduce uncertainties in the simulation result of propagating waves. It is essential to quantify the uncertainty in the simulation result when the acceptability of these calculation results is considered. To avoid performing thousands of full-wave simulations, an efficient surrogate model based on artificial neural networks (ANNs) is proposed in this paper, to imitate the concerned ground penetrating radar (GPR) calculation. With the autoencoder neural network to reduce the dimensionality of data, the surrogate model successfully predicts the outputs of the GPR calculation using a small number of training samples. The finite-difference time-domain method with the uniaxial perfectly matched layer is used to collect sampling data for the surrogate model. The process of constructing the surrogate model is presented in detail in this paper. The proposed surrogate model is demonstrated to be an attractive alternative to the full-wave GPR calculation due to its considerable advantage in terms of computational expense and speed.

Automatic modulation classification (AMC) is a key technology of cognitive radio used in non-cooperative communication. Recently, deep learning has been applied to AMC tasks. In this paper, an AMC scheme based on deep learning is proposed, which combines random erasing and attention mechanism to achieve high classification accuracy. Firstly, we propose two data augmentation methods, random erasing at sample level and random erasing at amplitude/phase (AP) channel level. The former replaces training samples with noise information, while the latter replaces AP channel information of training samples with noise information. Erased data segments are randomly stitched to enable training data expansion. Training data of different qualities enables deep learning model to have stronger generalization capability and higher robustness. Then, we propose a single-layer Long Short-Term Memory (LSTM) model based on attention mechanism. In the first part of this model, we propose the signal embedding, which enables the input to contain modulation information more comprehensively and accurately. Then hidden state output by LSTM is input into the attention module, and weighting is applied to the hidden state to help the LSTM model capture the temporal features of modulated signals. Compared to a model without attention mechanism, this model has faster convergence speed and better classification performance. Lastly, we propose a random erasing-based test time augmentation (RE-TTA) method. Test data is randomly erased for multiple times and classification results are comprehensively evaluated, in order to further improve classification accuracy. Experimental results on dataset RML2016.10a show that classification accuracy of the proposed scheme is competitive compared with the state-of-the-art methods.

With few exceptions1-3, polydispersity or molecular heterogeneity in matter tends to impede self-assembly and state transformation. For example, shape transformations of liquid droplets with monodisperse ingredients have been reported in equilibrium4-7 and non-equilibrium studies8,9, and these transition phenomena were understood on the basis of homogeneous material responses. Here, by contrast, we study equilibrium suspensions of drops composed of polydisperse nematic liquid crystal oligomers (NLCOs). Surprisingly, molecular heterogeneity in the polydisperse drops promotes reversible shape transitions to a rich variety of non-spherical morphologies with unique internal structure. We find that variation of oligomer chain length distribution, temperature, and surfactant concentration alters the balance between NLCO elastic energy and interfacial energy, and drives formation of nematic structures that range from roughened spheres to 'flower' shapes to branched filamentous networks with controllable diameters. The branched structures with confined liquid crystal director fields can be produced reversibly over areas of at least one square centimetre and can be converted into liquid crystal elastomers by ultraviolet curing. Observations and modelling reveal that chain length polydispersity plays a crucial role in driving these morphogenic phenomena, via spatial segregation. This insight suggests new routes for encoding network structure and function in soft materials.

Voice control has attracted extensive attention recently as it is a prospective User Interface (UI) to substitute for conventional touch control on smart devices. Voice assistants have become increasingly popular in our daily lives, especially for those people who are visually impaired. However, the inherently insecure nature of voice biometrics means that voice assistants are vulnerable to spoofing attacks as evidenced by security experts. To secure the commands for voice assistants, in this paper, we present a liveness detection system that provides continuous speaker verification on smart devices. The basic aim is to match the voice received by the smart device's microphone with the oral airflow of the user when speaking a command. The airflow is captured by an auxiliary commercial off-the-shelf airflow sensor. Specifically, we establish a theoretical model to depict the relationship between the oral airflow pressure and the phonemes in users' speech. The system estimates a series of pressures from the speech according to the theoretical model, and then calculates the consistency between the estimated pressure signal and the actual pressure signal measured by the airflow sensor to determine whether a command is a genuine "live" voice or an artificially generated one. We evaluate the system with 26 participants and 30 different voice commands. The evaluation showed that our system achieves an overall accuracy of 97.25% with an Equal Error Rate (EER) of 2.08%.

In this work, the PVDF/glass as-prepared composite membrane was prepared through phase-inversion method and used to adsorb methylene blue dye. The results of SEM and BET showed that the membrane had an asymmetric nanoscale porous structure. The electronegativity on the surface of membrane was determined through zeta potential test. The adsorption properties of as-prepared composite membrane and glass membrane were studied through testing the removal ratio of methylene blue from aqueous solution. Then the effects of membranes dose, pH value, temperature and initial concentration on the removal ratio were systematically studied. The adsorption mechanism was also studied. The adsorption kinetics and adsorption isotherm fitted well with the pseudo-second-order model and Freundlich model, respectively. In addition, the adsorption efficiency of glass membrane basically remained 85% after eight repeated adsorption-calcination cycles. The obtained membranes could be reused for methylene blue removal with high efficiency for multiply times.

A superhydrophobic fluorinated silica functionalized chitosan (F-CS) aerogel is constructed and fabricated by a simple and sustainable method in this study in order to achieve highly efficient gravity-driven oil/water separation performance. The fluorinated silica functionalization invests the pristine hydrophilic chitosan (CS) aerogel with promising superhydrophobicity with a water contact angle of 151.9°. This novel F-CS aerogel possesses three-dimensional structure with high porosity as well as good chemical stability and mechanical compression property. Moreover, it also shows striking self-cleaning performance and great oil adsorption capacity. Most importantly, the as-prepared aerogels exhibits fast and efficient separation of oil/water mixture by the gravity driven process with high separation efficiency. These great performances render the prepared F-CS aerogel a good candidate for oil/water separation in practical industrial application.

Spectrum handoff plays an important role in cognitive radio networks (CRNs). Secondary users (SUs) use spectrum handoff to hold on the idle channel or to free the channel for primary users (PUs). Spectrum handoff scheme greatly affects the transmission quality and the success rate of SUs connection. In this Letter, a reinforcement learning-based spectrum handoff scheme with the measured packet drop rate (PDR) for multimedia transmissions over CRNs is proposed. In a system model with multiple PUs and SUs, a new state space description method is designed and an observed state includes not only the status whether PUs arrive on each channel but also several other important factors. Also, the measured PDR, instead of the calculated one, is presented to update the mean opinion score, the Q-table and the handoff policy. Compared with the existing schemes with the calculated PDR from the Quality-of-Experience model, the authors' proposed scheme can converge more rapidly in the dynamic radio environment, and reduce the PDR of SUs more significantly.

A novel and simple switchable stacked artificial structure (SAS) is proposed and studied in phased arrays to realize a smart integration of broadband radar cross section (RCS) reduction and scanning range expansion. The proposed SAS is composed of a frequency selective surface (FSS) and a metamaterial absorber (MA). The lower part of the SAS can be switched between an FSS and a surface-waveguide (SWG) high-impedance surface (HIS) hybrid structure which can be used for wide-beam antenna design and array mutual coupling reduction. The upper part of the SAS can be seen as an MA. A linear phased array is presented and investigated based on the proposed switchable SAS. When the phased array is switched to its working mode, the SWG-HIS hybrid structure plays an important role to support a wide-angle scan from −75° to +75° with low sidelobes. When the phased array is shut down, the FSS-MA stacked structure can realize a low-RCS design in the frequency range of 0–11.2 GHz. An array prototype which operates at 4.6 GHz is fabricated and measured. The measured results have validated the radiation and scattering performance of the designed phased array.

With consideration about the different termination conditions of atomic layer, six kinds of YAlO3(001)/TiC(100) coherent interface models were selectively constructed based on the results of lattice mismatch calculation and surface convergence test. The work of adhesion and interfacial energy were calculated by first principles method, which is used to analyze their interface adhesive strength and stability to find out interface structures with excellent property. Charge density difference and electron localization functions were calculated to analyze interfacial atomic bonding characteristics. The YAlO3(001)/TiC(100) interfacial structure with the best grain boundary crack and displacement resistance were predicted by the adhesive sliding simulation and potential barrier calculation of preferable formed interfacial structures. The calculation results show that the lattice mismatch of YAlO3(001)/TiC(100) interfacial structures is very small, about 2.5%, which indicates they have the advantage of forming coherent interfaces. The work of adhesion of O1-Ti interface is the largest (Wad = 5.74 J/m2), which is followed by that of the O1-C interface (Wad = 5.73 J/m2). Their interface structures are similar and interfacial atomic bond type are both mixture of covalent bond (between O atom and C atom) and ionic bond (between O atom and Ti atom). However, the interfacial energy of O1-C is the smallest (γ = 2.16 J/m2), which reveals that the O1-C type YAlO3(001)/TiC(100) interface is the most stable. In addition, the sliding direction static friction force of O1-C model is 1.24 times larger than that of O1-Ti, and most of the O1-C interfacial barrier is larger than that of O1-Ti structure in a sliding period. Therefore, it can be predicted that a YAlO3(001)/TiC(100) interface with excellent combination property will be preferable formed in type of O1-C structure. The densification and mechanical property are expected to be greatly improved in TiC reinforced wear-resistance coating and other functional ceramics after adding YAlO3 additive.

The effect of hot isostatic pressing on the tensile property of single crystal superalloys at elevated temperature is studied experimentally. The results show that the high temperature elongation of nickel based single crystal superalloys is obviously enhanced by hot isostatic pressing, while the yield strength is unchanged. Besides, it is found that the hot isostatic pressing causes the change of fracture surface. The enhancement of elongation and the change of fracture behavior are discussed.

A simple method to fabricate redox-responsive composite hydrogel films via incorporating chitosan (CS) microspheres into carboxymethyl cellulose (CMC) hydrogel using a di-sulphide cross-linker cystamine dihydrochloride (CYS) have done in this paper. Dual drugs, an anticancer, 5-Fluorouracil (5-FU) and an antibiotic, Tetracycline Hydrochloride (TH) were used as model drugs. The prepared composite hydrogel films were characterized using FTIR, SEM, rheology measurement, mechanical and swelling tests. Our results showed that the well dispersed spherical CS microspheres endowed hydrogel film increased mechanical properties and swellability. In vitro drug release displayed an accelerated release under weak acidic or reducing media. The in vitro cytotoxicity and cell apoptosis studies showed the drug-loaded composite film caused enhanced inhibition to HepG2 cells in presence of glutathione (GSH). Moreover, the film has exhibited excellent antimicrobial efficacy against E.coli and Staphylococcus aureus. Therefore, our simple and effective dual drug-loaded system has the potential to be used for cancer therapy in the future.

In this paper, we focus on designing and implementing SmartMeeting, an intelligent system for generating meeting minutes from meeting audio data. SmartMeeting mainly consists of four parts: the first part is the meeting speech detection, which is used to automatically extract multiple speech segments of each speaker and then sort them by time, and mark the corresponding speakers separately in different time periods; The second part is the meeting voice text transcription, the voice segment cut in the previous step is transcribed into a complete meeting text; The third part is the extraction of the meeting minutes, extracting meaningful key phrases and abstract sentences from the complete meeting text; The fourth part is the next work plan extraction, through the emotion recognition algorithm to filter out the negative emotion summary from the multiple meeting minutes, so as to show the next work plan of the meeting. By comparing and evaluating different baseline algorithms on real-world audio meeting datasets, experiments have proven that SmartMeeting can accurately summarize meetings and analyze agreed actions.

The travelling officer problem (TOP) is a graph-based orienteering problem for modelling the patrolling routines of a parking officer monitoring an area. Recently, a spatiotemporal probabilistic model was built for TOP to estimate the leaving probability of parking cars, and relevant algorithms were applied to search for the optimal path for a parking officer to maximize the collection of parking fines from cars in violation. However, there are often multiple parking officers on duty during business hours in the central business district, which provides us with the opportunities to introduce cooperation among officers for efficient car-parking management. The multiple travelling officers problem (MTOP) is a more complex problem than the TOP because multiple officers are involved simultaneously in paths construction. In this study, the MTOP is formulated and new components are established for solving the problem. One essential component called the leader-based random-keys encoding scheme (LERK) is developed for the representation of possible solutions. Then, cuckoo search (CS), genetic algorithm (GA) and particle swarm optimization (PSO) are implemented using the proposed components and compared with other state-of-the-art GA and PSO using other solution encoding schemes to solve MTOP. In addition, two greedy selection algorithms are adopted as baselines. The performance of the algorithms is evaluated with real parking sensors data and different metrics. The experimental results show that the performance of CS and GA using LERK is considerably improved in comparison with that of other implemented algorithms.

The MnO2@P(AN-VDC)/AC composite fibers were prepared using impregnation and coupling method, respectively. MnO2 particles were dispersed uniformly on the surface of coupling composite fiber using PVA as the coupling agent at the concentration of 6 wt%. The MnO2@P(AN-VDC)/AC composite fibers which was fabricated by coupling method offered better adsorption property towards formaldehyde than that via impregnation procedure. Meanwhile, activated carbon (AC) was also beneficial for the HCHO adsorption. As the increasing of content of activated carbon, the HCHO adsorption amount was enhanced. With the high adsorption efficiency of the P(AN-VDC)/AC fibers and the adsorption affinity of MnO2, the fabricated MnO2@P(AN-VDC)/AC composite fibers provided a way for the removing of the harmful VOC formaldehyde.

The Co-Al coating was deposited on Ni-based superalloy DZ125 by pack cementation. The lifetime and interdiffusion behavior of the Co-Al coating on the Ni-based superalloy at 1050 °C, 1075 °C and 1100 °C were investigated. Surface oxidation and interdiffusion between the coating and the substrate led to depletion of Al in the coating, and β-Ni(Co)Al was gradually degraded into γ and γ' phases. Oxidation activation energy of the coating was calculated through oxidation weight gain curves of different temperatures. The formula of the coating lifetime related to the coating thickness and the temperature was established by calculating intermediate parameters. The lifetime determined by the formula and experiment showed good agreement.

A bandwidth-enhanced pattern reconfigurable antenna (PRA) based on surface waves is presented. The PRA consists of a surface-wave guide (SWG), a windmill-shaped feeding network (WSFN) and four grou...

In this work, a new method for facile synthesis of covalently colored polyurethane latex was developed. A series of blue dye monomers were synthesized via one-step reaction of a reactive dye and amino compounds, and then employed as chain extenders to react with polyurethane prepolymer in the emulsification process to prepare the covalently colored polyurethane latexes. The chemical structures and the properties of dye monomers and the corresponding polymers were investigated, and the UV–Vis spectra of covalently colored polyurethane featured fairly consistent with dye monomers with maximum absorption wavelength at 620 nm and 580 nm, since the chemical structure of chromophore maintained unchanged. The conversion of dye monomer reached more than 92% with 1.0 wt% dye content, whereas the conversion decreased with the increase of the dye amount and the adding time. Compared with the noncovalently latex film, the light fastness of the covalently colored latex film was greatly promoted due to the chemical bonding of chromophores with polymer matrix.

Flexible strain sensor devices were fabricated by depositing Pd nanoclusters on PET membranes patterned with interdigital electrodes. The sensors responded to the deformation of the PET membranes with the conductance changes of the nanocluster films and were characterized by both high gauge factor and wide detection range. The response characteristics of the strain sensors were found to depend strongly on the nanocluster coverage, which was attributed to the percolative nature of the electron transport in the closely spaced nanocluster arrays. By controlling the nanocluster deposition process, a strain sensor composed of nanocluster arrays with a coverage close to the effective percolation threshold was fabricated. The sensor device showed a linear response with a stable gauge factor of 55 for the applied strains from the lower detection limit up to 0.3%. At higher applied strains, a gauge factor as high as 200 was shown. The nanocluster films also demonstrated the ability to response to large deformations up to 8% applied strain, with an extremely high gauge factor of 3500.

In this letter, a linear wide-scan phased array using a polarization-conversion isolator (PCI) is analyzed and designed. The directivity of a linear array composed of isotropic sources against the scanning angle is investigated to reveal that the mutual coupling (MC) between adjacent elements is the major constraint on the scanning range when the interelement spacing is less than half free-space wavelength. A PCI is adopted to broaden the scanning range, and the MC reduction principle is studied. A 16-element linear phased array with the PCIs is designed. A prototype is fabricated and measured, and the measured results show that the designed array can scan its main beam from $-72^\circ$ to +72 $^\circ$ with a gain fluctuation less than 2.5 dB. Besides, the variation of the array realized gain with the scan angle validates that the linear array layout benefits for the scanning range.

In this letter, we report the results of an investigation of multimode microstrip patch resonators and their applications for designing dual-polarized wide-angle scanning phased arrays. The proposed multimode patch element can provide broadside (TM01 or TM10 modes) and monopole-like (TM21 mode) patterns which are combined to obtain a joint wide-beam coverage in both xoz and yoz planes. By interactively selecting these modes, the formed 8 × 8 planar phased array can scan its main beam from −64° to +64° in the two orthogonal planes. Measured results validate some notable features, such as the dual-plane wide-angle scan with the same polarization and high realized gain with low sidelobe levels.