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Solving constrained multiobjective optimization problems brings great challenges to an evolutionary algorithm, since it simultaneously requires the optimization among several conflicting objective functions and the satisfaction of various constraints. Hence, how to adjust the tradeoff between objective functions and constraints is crucial. In this article, we propose a dynamic selection preference-assisted constrained multiobjective differential evolutionary (DE) algorithm. In our approach, the selection preference of each individual is suitably switching from the objective functions to constraints as the evolutionary process. To be specific, the information of objective function, without considering any constraints, is extracted based on Pareto dominance to maintain the convergence and diversity by exploring the feasible and infeasible regions; while the information of constraint is used based on constrained dominance principle to promote the feasibility. Then, the tradeoff in these two kinds of information is adjusted dynamically, by emphasizing the utilization of objective functions at the early stage and focusing on constraints at the latter stage. Furthermore, to generate the promising offspring, two DE operators with distinct characteristics are selected as components of the search algorithm. Experiments on four test suites including 56 benchmark problems indicate that the proposed method exhibits superior or at least competitive performance, in comparison with other well-established methods.

Herein, a series of 6BaO·1CaO·2Al2O3 + x wt% Sc2O3 (x = 1, 3, 5, 7, 9) impregnants were synthesized by a liquid-phase co-precipitation method and subsequent sintering at 1200 °C. The as-synthesized emissive materials were impregnated into porous tungsten matrices at 1700 °C, and their phase composition and electron emission performance were investigated. The X-ray diffraction analysis of the sintered and melted impregnated products revealed that they comprised multi-phase structures consisting of (Ba,Ca)3Al2O6, Ba2ScAlO5, and BaAl2O4 phases. Furthermore, the addition of 3 wt% Sc2O3 to the impregnated test cathodes significantly increased the emission level of the test cathode to 11.4 ± 0.6 A cm−2 at 1100 °CB (i.e., brightness temperature). The relationship between the electron emission properties and phase concentration in the impregnants was analyzed, and the results revealed that the emission performance of the cathodes deteriorated with an increase in the Sc2O3 content, which could be attributed to an increase in the concentration of non-active BaAl2O4 phase in the impregnants.

This letter presents a parameter identification of the series inductance in dual active converter. In the optimized modulation strategies and feedforward control, the series inductance is a key parameter to determine the performance of the converter. The series inductance is varied with many factors, such as the temperature, air gap, and switching frequency. The deviation value of the series inductance will cause the failure of the control strategy. In this letter, a parameter identification method is presented based on the recursive least squares algorithm. By using this method, the real value of the series inductance is derived. Finally, the effectiveness of the identification method is verified by the feedforward control in dual active bridge converters. The feedforward control can achieve good dynamic response by using the identification method, even if the real series inductance value is unknown.

In this article, a broadband $W$ -band $\mathrm{TE}^{\square }_{10}$ – $\mathrm{TE}^{\bigcirc }_{02}$ mode converter is proposed and verified. To improve the output performance of the $\mathrm{TE}^{\square }_{10}$ – $\mathrm{TE}^{\bigcirc }_{02}$ mode converter, a $\mathrm{TE}^{\square }_{10}$ -to- $\mathrm{TE}^{\square }_{40}$ intermediate mode conversion section with a Y-type power divider structure and a $\mathrm{TE}^{\times }_{44}$ -like-to- $\mathrm{TE}^{\bigcirc }_{02}$ intermediate mode conversion section with a novel cross-sector-shaped transition structure are adopted in the design (the superscript symbol $^{\square }$ represents the rectangular waveguide, $^{\bigcirc }$ represents the circular waveguide, $^{\times }$ represents the cross waveguide). The simulation results show that the transmission coefficient (S21 parameter) of the designed $\mathrm{TE}^{\bigcirc }_{02}$ mode converter is better than −0.18 dB in the whole $W$ -band (75–110 GHz), and the corresponding mode conversion efficiency is larger than 96%. Cold test results show that the transmission coefficient is higher than −1.9 dB and the reflection coefficient (S11 parameter) is less than −15 dB in the frequency range of 75–110 GHz.

This article proposes a longitudinal output structure in Ka-band sheet beam traveling-wave tube (SBTWT) with an ultrawideband transmission and high breakdown collector voltage. A novel electromagnetic bandgap (EBG) cutoff structure is designed to separate the slow-wave structure (SWS) and the depressed collector. The large stopband property of the EBG structure is applied to achieve not only the high transmission and the low gap leakage but also the long gap distance to provide a high breakdown voltage of the depressed collector. The 3-D simulations of a single longitudinal structure show a full Ka-band (26.5–40 GHz) reflection of less than −20 dB and gap leakage less than −0.02 dB. The entire longitudinal output collector, including two large gaps cutoff structures and the over mode electron collecting parts, is designed and manufactured. The simulations show a bandwidth of 10.4 GHz with a reflection coefficient ${S} _{\mathbf {11}}$ of lower than −20 dB. The cold test demonstrates the wild bandwidth of ~11.1 GHz with a reflection coefficient ${S} _{\mathbf {11}}$ of lower than −15 dB. The hot test reveals a stable collector dc voltage of −14.2 kV.

Titanium cermet combining metallic toughness with ceramic wear resistance has been proven to be a potential candidate for implanted joint material. In this work, titanium cermet was synthesized by means of the elevated temperature solid carburizing technology. The Ti13Nb13Zr alloy surface was found to be converted into TiC ceramic layer combined with a carbon strengthened diffusion zone underneath. The overall thickness of the carburized region grew to about 100 µm after 120 min carburization at 1,500 K. In order to clarify the growth behaviors of TiC ceramic layer, a growth mechanism is proposed. At the beginning of carburizing process, carbonaceous gas decomposed from carburizer due to high temperature and then converted to free atomic carbons through reduction reaction. Then, in-situ generated TiC ceramic layer possessing certain thickness formed on the surface, meanwhile, the inner carbon diffusion zone also grew inwards due to physical diffusion of carbon, and finally forming a gradient carbon distribution. In addition, the tribological behaviors of the new materials were evaluated through reciprocating ball-on-plate sliding wear tests in bovine calf serum. Although there was an increase in friction coefficient, the wear rate decreased by 59.6% due to the formation of the wear-resistant TiC ceramic layer. The wear mechanisms evolved from severe abrasive wear for bare Ti13Nb13Zr alloy to mild adhesive wear for titanium cermet.

Aiming at the difficulty of obtaining a large number of labeled samples of the shortwave receiving system, an intelligent diagnosis method for the shortwave receiving system based on the improved Laplacian SVM algorithm is proposed. By introducing the idea of neighborhood density into the adjacency graph construction of Laplacian SVM, the manifold structure information of samples is more fully mined, thus improving the performance of Laplacian SVM classifier and realizing the optimization of traditional Laplacian SVM. KFCM clustering algorithm was used to select unlabeled boundary samples and labeled samples to form the reduction training set. The method of the KFCM pre-selection sample was combined with the improved Laplacian SVM algorithm to enhance the learning efficiency. The simulation results using the UCI data set and the experimental verification results of shortwave receiving system sample data indicate that the proposed algorithm could more fully mine the manifold structure information of samples and improve the performance of the Laplacian SVM classifier.

Design and exploitation of flame retardant polymers with high electrical conductivity are desired for polymer applications in electronics. Herein, a novel phosphorus-nitrogen intumescent flame retardant was synthesized from pentaerythritol octahydrogen tetraphosphate, phenylphosphonyl dichloride, and aniline. Low-density polyethylene was combined with the flame retardant and multi-walled carbon nanotubes to form a nanocomposite material via a ball-milling and hot-pressing method. The electrical conductivity, mechanical properties, thermal performance, and flame retardancy of the composites were investigated using a four-point probe instrument, universal tensile machine, thermogravimetric analysis, and cone calorimeter tests, respectively. It was found that the addition of multi-walled carbon nanotubes can significantly improve the electrical conductivity and mechanical properties of the low-density polyethylene composites. Furthermore, the combination of multi-walled carbon nanotubes and phosphorus-nitrogen flame retardant remarkably enhances the flame retardancy of matrixes with an observed decrease of the peak heat release rate and total heat release of 49.8% and 51.9%, respectively. This study provides a new and effective methodology to substantially enhance the electrical conductivity and flame retardancy of polymers with an attractive prospect for polymer applications in electrical equipment.

Sheet beam vacuum electron tubes are an attractive solution for high-power sources or amplifiers at millimeter-wave and terahertz range. In this article, a high-order coalesced TM11-like mode operation for 220 GHz sheet beam traveling-wave tube is proposed. The feasibility of coalesced TM11-like mode operation is investigated. The utilization of high-order mode expands the RF circuit power capacity, increases the beam current and reduces the cathode emission density. The self-consistent nonlinear code and three-dimensional particle-in-cell simulations are used to verify the 6.7% beam-wave interaction at 220 GHz without phase matching optimization. The maximum output power reaches 370 W. The results demonstrate this methodology is a good solution to build a high-power device for a wide region of terahertz.

This letter proposes an inline, ultrawideband, and low loss transition from microstrip line (MSL) to ridge gap waveguide (RGW). An efficient conversion between operational mode of RGW and the quasi-TEM mode of MSL is presented by using suspended line patch as a bridge. Furthermore, the effect of loading a capacitive iris on the transition matching performance is studied and a methodology to tune the transition bandwidth is proposed. In order to validate the presented solution, a back-to-back transition prototype is developed and investigated experimentally. The measured results show an insertion and return loss of 0.4 and 15 dB, respectively, over 107% relative bandwidth in the range of 6.2–20.1 GHz.

In order to detect the defects of smart meter liquid crystal display (LCD) screen quickly and accurately, this paper proposes a method based on line segment detector (LSD) and deep learning. Characters of smart meter LCD screen can be divided into two types: ordinary characters and digital tube characters. Convolutional neural network (CNN) is used to locate and identify the ordinary characters. Since there may be certain missing segment in digital tube characters, conventional text detection methods are not applicable, and template matching method is used for detecting them. Compared with the whole screen, the digital tube area is very small, and the relative positions of the digital tube characters of smart meter of most manufacturers are nearly the same, so the detection rate of the template matching method is extremely high and the method can be commonly used. The whole detection process is as follows: First, horizontal straight lines got by LSD are used for tilt correction. Secondly, CNN is used to locate and identify an ordinary character of the meter screen to determine whether it is missing or not. Then, whether there are missing segments in the digital tube area is determined by template matching method. At last, the experimental results show that the accuracy of the method for detecting the character defects of LCD screen is about 96%, and the accuracy of the electric quantity identification function of the method is about 97%.

In this communication, we report the scanning manipulation on radiation beams with an active metamaterial (MTM) antenna using p-i-n diode switches. Thanks to the MTM antenna possessing periodical configuration with isolated units, p-i-n diodes in each unit are capable of being actuated individually with OFF/ON-states (coding sequences 0/1), equivalently tuning the phase constant $\beta $ of each cell either in state $\beta _{0}$ or state $\beta _{1}$ . Therefore, for MTM array with a certain number of units, we can obtain plenty of tunable states presented via digitally coding sequence combinations, thereby manipulating beam scanning in a fixed frequency band. Especially, for the first time, we propose the digitally modulated array factor (DMAF) method for the MTM array: introducing unit-cell dispersion curves of both 0/1 states to the array factor, thus, map the digitally coding sequences linearly to the scanning beams at a fixed frequency, resulting in scanning functionalities. Experiments are implemented with applying micro-control-unit (MCU) to the active MTM antenna for driving p-i-n diodes, and measurements demonstrate beam scanning continuously from −30° to +30° at fixed frequencies around 5 GHz, validating the proposed method.

P2.5 plug-in hybrid electric vehicles (P2.5-PHEVs) exhibit high transmission efficiencies and no power interruption in the shifting and mode switching process; thus, they have broad application prospects. The power transmission in a PHEV under pure electric startup does not entail the clutch, and the initial torque of the motor is often set under the condition that the maximum allowable slope should not lead to backward sliding, which leads to the problems of excessive jerk in small-slope startup and catapulting when startup occurs downhill. The optimal method is to set different initial torques according to different gradients; however, the vehicle would still be in the pre-startup stage, making it impossible to estimate the slope using a dynamic method. In view of the foregoing problems, according to an analysis of pure electric startup dynamics, a slope-memory-based strategy for estimating and storing the slope during the vehicle movement before parking is proposed. During startup, the initial torque is set according to the memorized slope. In the processes of startup and acceleration, the driver’s startup intention is identified, and different jerk control targets are set. The torque of the acceleration process is controlled according to the set initial torque and jerk target. Simulation results indicate that the maximum jerk of the proposed strategy is reduced by 23.6% for startup on a 5% ramp and by 57.5% for startup at 15% downhill; thus, the strategy mitigates the problems of the excessive jerk and catapult for startup on a small slope.

(Ba,Ca)2ScAlO5 compounds are synthesized and improved emission performance is achieved by virtue of their single-phase structure and low work function. The substitution of Ca2+ for Ba2+ effectively lowers the melting points of (Ba,Ca)2ScAlO5 from over 1800 °C–1700 °C when the Ca2+ substitution reaches 20 at%. During sintering, the co-precipitation precursor first reacts to form (Ba,Ca)3Al2O6 near 912 °C before reacting with BaCO3 and Sc2O3 at the higher temperature of 1186 °C to generate (Ba,Ca)2ScAlO5. Emission tests reveal that the maximum full space charge current density is 9.6 A cm−2 at 1000 °CB (brightness temperature) for the cathode impregnated with single-phase (Ba,Ca)2ScAlO5. Low work function (~1.5 eV) and good emission uniformity make such a cathode promising for applications in high-power microwave devices.

Silicone rubber (VMQ)/functionalized graphene (FG) nanocomposite foams with low density and better deformation recovery capability were successfully prepared by environmental-friendly supercritical...

The performance of a wheel loader (WL) can be improved with the application of a power reflux hydraulic transmission system (PRHTS) with a capacity adjustment device (CA-device). However, due to CA-device’s unique working principle, the traditional shifting strategy is not suitable for CA-device. Apply traditional shifting strategy to CA-device will result in frequent or incorrect shifting. In order to solve this problem, this paper proposes applying the working condition identification to the CA-device shifting strategy. Combining the working principle of PRHTS with CA-device and the analysis of WL V-condition, the requirement for the working condition identification algorithm of the CA-device shifting strategy is obtained, and a working condition identification algorithm for WL V-condition is designed. Simulation results show that applying the working condition identification algorithm to the CA-device shifting strategy can avoid frequent shifts and incorrect shifts. A hardware-in-the-loop platform is built to verify the real-time performance of the shifting strategy. Results show that the proposed shifting strategy exhibits a satisfactory level of real-time performance.

Design and measurement of a broadband compact circular TE11 mode input coupler for gyrotron traveling wave tubes (gyro-TWTs) are presented in this article. Different from the T-junction, Y-type, and multiple-hole input couplers, the proposed coupler has a merit of compact dimensions formed by the H-plane of a rectangular cavity. The simulation results show that the port reflection $S_{11}$ is less than −10 dB within 7.9–9.93 GHz. Also, the split transmissions $S_{21}$ and $S_{31}$ are over −3.4 dB in this band. It indicates that the relative bandwidth is 22.8%, and the transmission efficiency is higher than 90%. To further broaden the bandwidth, we propose an improved input coupler with ridges achieving an excellent bandwidth of 28.6%. The designed input coupler has been measured with open boundaries and matched output ports. The simulation and measurement results are in good agreement. The compact TE11 mode input coupler had been applied in our X-band gyro-TWT design.

A periodic dielectric meta-surface structure was designed to extend the output window operating bandwidth of a wideband TE 01 mode gyrotron travelling wave tube. The equivalent permittivity of the meta-surface matching layer can be adjusted arbitrarily by changing the lattice dimensions. The fabricated meta-surface dielectric window demonstrated a relative bandwidth of 53.9% with a reflection below − 20 dB in the Ka- and Q-band.

Since Electric Auxiliary Systems (EAS) accounts for a large proportion of electric bus energy consumption, in order to reduce EAS energy consumption and improve bus driving range, the working princ...

The wetting behavior of glass coatings on samarium-cobalt alloys with different roughness at elevated temperatures in air was investigated by a sessile drop method. The wetting properties were analyzed through several parameters, including apparent contact angle, height and diameter of a glass cylinder on the samarium-cobalt alloy, determined by using a high temperature microscope. The morphology evolution of the glass coating was observed by using a scanning electron microscope. The results show that the glass cylinder contracts initially, and then swells followed by wetting and spreading on the samarium-cobalt alloy substrate. This process is explained by the role of air and the increase of capillary number. The dependence of apparent contact angle on surface roughness is related to interface reaction. It is concluded that the surface roughness firstly increases the contact angle, but then promotes wetting due to the wetting transition changing from the Cassie−Baxter state to the Wenzel state in the non-reactive wetting range. The surface roughness hinders the spreading of the glass melt due to the interface reaction between glass and samarium-cobalt alloys in the reactive wetting range.

A rotating packed bed (RPB) reactor has substantially potential for the process intensification of heterogeneous catalytic reactions. However, the scarce knowledge of the liquid–solid mass transfer in the RPB reactor is a barrier for its design and scale-up. In this work, the liquid–solid mass transfer in a RPB reactor installed with structured foam packing was experimentally studied using copper dissolution by potassium dichromate. Effects of rotational speed, liquid and gas volumetric flow rate on the liquid–solid mass transfer coefficient (kLS) have been investigated. The correlation for predicting kLS was proposed, and the deviation between the experimental and predicted values was within ± 12%. The liquid–solid volumetric mass transfer coefficient (kLSaLS) ranged from 0.04–0.14 1−1, which was approximately 5 times larger than that in the packed bed reactor. This work lays the foundation for modeling of the RPB reactor packed with structured foam packing for heterogeneous catalytic reaction.

Contact forces and transmission efficiency of an automotive ball joint constitute important design goals of an automotive drive shaft system, which affect transmission performances of the ball joint and the drive shaft system. In order to analyze contact forces and transmission efficiency more comprehensively, a multi-body dynamic model for calculating contact forces and transmission efficiency of a ball joint is established. The effectiveness of the multi-body dynamic model is validated through experiments of contact forces and transmission efficiency of a ball joint. Based on the developed multi-body dynamic model, influences of the articulation angle, the ball number and the track offset on contact forces between the ball and the cage, and between the ball and the track are analyzed. To enhance the analysis and optimization efficiency of transmission efficiency, a proxy model for the transmission efficiency loss late is established on the basic of the multi-body dynamic model. Influences of the ball radius, the articulation angle, the friction coefficient, the central angle of the cross section of the cage rib, and the contact stiffness and the force exponent of contact pairs on the transmission efficiency loss late are analyzed. Using Sobol’ global sensitivity analysis method, the sensitivity of the proxy model is analyzed and influences of various factors on the transmission efficiency loss late are further determined. According to sensitivity analysis results, the articulation angle, the friction coefficient and the force exponent are selected as design parameters, and the transmission efficiency loss late is optimized through a numerical example.

Wire mesh packing has been extensively utilized in laboratory and industry applications in rotating packed bed (RPB) because of the high mass transfer performance and low cost. Conventional wire me...

Introduction Although carbon nanospheres (CNPs) are promising nanomaterials in cancer treatment, how they affect prostate cancer (PCa) remains unclear. Methods In this study, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy were used to confirm the successful synthesis of CNPs. CCK-8, flow cytometry, Transwell, wound healing, Western blot and immunohistochemistry (IHC) assays were performed to evaluate the antitumor effect of CNPs toward the two kinds of prostate cancer cell lines PC3 and DU145. Results Our results showed that CNPs inhibited cell growth, invasion, and migration and induced apoptosis and autophagy in PCa cells. Multifactor detection of a single Akt phosphorylation pathway and Western blot results suggested the suppression of 4E-BP1 in PCa cells after incubation with CNPs. The results from animal experiments also suggested the antitumor effect of CNPs and reduced 4E-BP1 expression in PCa tissue samples from BALB/c nude mice administered a local subcutaneous injection of CNPs.

In the warming climate, flood risk is likely to increase over much of the globe. We present projections of changes of flood losses in China for a range of global warming scenarios, from 1.5° to 4.0°C above the preindustrial temperature, with a 0.5°C step. Projections of flood losses in China are based on river runoff simulations by a distributed hydrological model driven by multiple downscaled general circulation models, the national GDP projected at shared socioeconomic pathways, and the “intensity–loss rate” function. When interpreting changes caused by the combined effect of economic and climatic conditions, flood losses in China are projected to soar in the future, particularly in lowland regions subject to rapid economic growth. Under global warming of 1.5° and 4.0°C, in an average year, flood losses are projected to be, respectively, 4 and 17 times that at present. Pursuing the international climate policy target of limiting global warming is projected to reduce exposure to floods in China. In this way, flood losses in China can be reduced by tens of billions of U.S. dollars (on average, US$67 billion and up to 0.04% of GDP) for each 0.5°C that warming is reduced. Our study improves understanding of the impact of climatic and nonclimatic changes on flood risk. Our scientific contribution is the first study to quantify flood impacts across China under different development pathways (shared socioeconomic pathways) for a broad range of global warming levels.

To realize multiband mode conversion in the high-power microwave (HPM) application system, a novel compact dual-band mode converter based on a universal method is proposed in this article. The proposed converter has a hybrid circular-embedded coaxial structure, and it integrates the conventional plate-inserted coaxial TEM-TE11 converter and serpentine circular TM01-TE11 converter simultaneously. Its outer and inner waveguides have the same curvature distributions along a longitudinal direction. Both the numerically calculated results and simulations exhibit that its maximum conversion efficiencies at two central frequencies are over 99% with a structure length of 240 mm. Simulated results indicate that the bandwidths reach 390 MHz (at ${X}$ -band) and 4.2 GHz (at Ka-band), respectively, when the conversion efficiencies are over 95%. A prototype is fabricated and measured. The far-field results demonstrate that coaxial TE11 and circular TE11 modes with high purity are detected at the output port of converter, and the S-parameter measurements illustrate that high conversion efficiencies at 8.4 and 30.5 GHz are obtained. The measurement results have a good agreement with the theoretical predictions and simulations.

This article proposes a synthesis method based on phase modulation to design broadband oversized smooth-walled horns for high-power millimeter-wave applications. The bandwidth of oversized smooth-walled horn is confined by the mismatch of the relative phase between TE11 mode and TM11 mode. By analyzing the mode conversion along horn, it is found that the phase of the generated TM11 mode can be influenced by the TE11 mode. Therefore, the synthesis method uses a slow waveguide taper, in which the generated TM11 mode is in a small fraction and its phase is efficiently influenced by TE11 mode, to modulate the relative phase of TE11 mode and TM11 mode. Using the proposed method, an oversized smooth-walled horn is designed, of which the phase mismatch is ±10° in the range of 32–38 GHz. The simulation results show that the proposed horn has a highly symmetric far-field pattern with a peak gain greater than 28 dBi in the range of 32–38 GHz and the sidelobe level has −19 dB decline compared with the peak gain. A prototype is fabricated and the near-field pattern measurement is carried out. The high correspondence of the simulated near-field patterns with the measured ones proves that the proposed method is an appropriate option to design broadband feed horns for high-power millimeter wave.

The quantitative determination of crack damage stress is of significant importance for investigating rock deformation and failure. In this study, a new quantitative method for determining the crack damage stress of rock materials was proposed based on acoustic emission (AE) signal detection. Ten rock materials were subjected to uniaxial compression testing, during which real-time AE signals and axial, lateral, and volumetric strain values were recorded. The AE cumulative count curves of the different rock materials were calculated based on the AE counts. These curves were divided into three stages as the axial stress increased: the slowly increasing stage, the steady stage, and the sharply increasing stage. The point where the sharply increasing stage began was defined as the PR point and could be accurately determined based on a fitting optimization method. Then, the damage stress was calculated by using the crack volumetric strain model. Finally, the relationship between the R stress (axial stress corresponding to the PR point) and the crack damage stress was investigated for the ten rock materials. The results showed that there was a good correspondence between the R stress and the crack damage stress. Hence, the R stress can be used to determine the crack damage stress and the starting point of the unstable crack growth stage in rock materials.

Face recognition is one of the core and challenging issues in computer vision field. Compared to computer vision, human visual system can identify a target from complex backgrounds quickly and accurately. This paper proposes a new network model deriving from Where-What Networks (WWNs), which can approximately simulate the information processing pathways (i.e., dorsal pathway and ventral pathway) of human visual cortex and recognize different types of faces with different locations and sizes in complex background. To enhance the recognition performance, synapse maintenance mechanism and neuron regenesis mechanism are both introduced. Synapse maintenance is used to reduce the background interference while neuron regenesis mechanism is introduced to regulate the neuron resource dynamically to improve the network usage efficiency. Experiments have been conducted on human face images of 5 types, 11 sizes, and 225 locations in complex backgrounds. Experiment results demonstrate that the proposed WWN model can basically learn three concepts (type, location and size) simultaneously. The experiment results also show the advantages of the enhanced WWN-7 model for face recognition in comparison with several existing methods.

Jie Xiong,1 Binglei Jiang,1 Yong Luo,1 Jianzhong Zou,1 Xuan Gao,1 Die Xu,1 Yan Du,1,2 Lan Hao3 1State Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing Key Laboratory of Biomedical Engineering, Chongqing Medical University, Chongqing 400016, People’s Republic of China; 2Ultrasonography Department, The Fourth People’s Hospital of Chongqing, Central Hospital of Chongqing University, Chongqing 400014, People’s Republic of China; 3Institute of Ultrasound Imaging, Chongqing Medical University, Chongqing 400010, People’s Republic of ChinaCorrespondence: Jianzhong ZouCollege of Biomedical Engineering, Chongqing Medical University, Chongqing 400010, People’s Republic of ChinaTel +86 13783002390Email zoujzh@cqmu.edu.cnPurpose: Focused ultrasound (FUS) is a noninvasive method to produce thermal and mechanical destruction along with an immune-stimulatory effect against cancer. However, FUS ablation alone appears insufficient to generate consistent antitumor immunity. In this study, a multifunctional nanoparticle was designed to boost FUS-induced immune effects and achieve systemic, long-lasting antitumor immunity, along with imaging and thermal enhancement.Materials and Methods: PEGylated PLGA nanoparticles encapsulating astragalus polysaccharides (APS) and gold nanorods (AuNRs) were constructed by a simple double emulsion method, characterized, and tested for cytotoxicity. The abilities of PA imaging and thermal-synergetic ablation efficiency were analyzed in vitro and in vivo. The immune-synergistic effect on dendritic cell (DC) differentiation in vitro and the immune response in vivo were also evaluated.Results: The obtained APS/AuNR/PLGA-PEG nanoparticles have an average diameter of 255.00± 0.1717 nm and an APS-loading efficiency of 54.89± 2.07%, demonstrating their PA imaging capability and high biocompatibility both in vitro and in vivo. In addition, the as-prepared nanoparticles achieved a higher necrosis cell rate and induced apoptosis rate in an in vitro cell suspension assay, greater necrosis area and decreased energy efficiency factor (EEF) in an in vivo rabbit liver assay, and remarkable thermal-synergic performance. In particular, the nanoparticles upregulated the expression of MHC-II, CD80 and CD86 on cocultured DCs in vitro, followed by declining phagocytic function and enhanced interleukin (IL)-12 and interferon (INF)-γ production. Furthermore, they boosted the production of tumor necrosis factor (TNF)-α, IFN-γ, IL-4, IL-10, and IgG1 (P< 0.001) but not IgG2a. Immune promotion peaked on day 3 after FUS in vivo.Conclusion: The multifunctional APS/AuNR/PLGA-PEG nanoparticles can serve as an excellent synergistic agent for FUS therapy, facilitating real-time imaging, promoting thermal ablation effects, and boosting FUS-induced immune effects, which have the potential to be used for further clinical FUS treatment.Keywords: immune, immunoadjuvant, thermal ablation, PLGA, Chinese traditional medicine

Four groups of numerical models of Brazilian tests on rock-shotcrete interfaces were successfully conducted by PFC2D. The tensile strength and Young’s modulus of shotcrete were considered. Six different undulations of rock-shotcrete interface were set up. The influences of multiple parameters on the bearing characteristics of the rock-shotcrete interface were studied. The results showed that a better support performance can be obtained by increasing the Young’s modulus of shotcrete rather than the tensile strength of shotcrete. For different tensile strength and Young’s modulus, the increase of sawtooth height has different effects on the support performance. The failure mechanism of the rock-shotcrete interfaces was analysed in detail. The stress shielding effect and stress concentration effect caused by the shape characteristics of rock-shotcrete interface were observed. The influence of these parameters on the overall support performance should be fully considered in a reasonable support design.

Porous SiC ceramic membrane supports are widely employed in a wide variety of high-temperature applications, such as hot flue gas filtration, porous burners and molten metal filters. Herein, SiC supports, with a porosity of ~37%, were prepared by using low-temperature bonding techniques and the influence of different bonding phases, such as mullite, cordierite and glass, on ambient-temperature flexural strength, hot modulus of rupture (HMOR), thermal shock resistance and oxidation resistance were systematically investigated. The results reveal that the glass-bonded SiC (GBSC) support exhibited the highest ambient-temperature flexural strength of 33.6 MPa, whereas the flexural strength of mullite-bonded SiC (MBSC) and cordierite-bonded SiC (CBSC) supports ranged from 22 to 25 MPa. However, the presence of glass phase deteriorated the high-temperature properties of the support. MBSC support rendered superior mechanical strength at high temperature and self-strengthening in a certain temperature range, such as HMOR improved 47.5% at 900 °C, but HMOR of glass-bonded support was only 57.4% of the ambient-temperature strength. Moreover, MBSC and CBSC supports exhibited better thermal shock resistance than GBSC supports and the critical temperature difference of water quenching for MBSC supports was ~200 °C higher than GBSC supports. In addition, MBSC support rendered superior oxidation resistance and exhibited a weight gain rate of ~0.1% at 1150 °C for 24 h, which is 54.4% and 42.2% lower than CBSC and GBSC supports, respectively.

Wireless multimedia big data contains valuable information on users' behavior, content characteristics and network dynamics, which can drive system design and optimization. The fundamental issue is how to mine data intelligence and further incorporate them into wireless multimedia systems. Motivated by the success of deep learning, in this work we propose and present an integration of wireless multimedia systems and deep learning. We start with decomposing a wireless multimedia system into three components, including end-users, network environment, and servers, and present several potential topics to embrace deep learning techniques. After that, we present deep learning based QoS/QoE prediction and bitrate adjustment as two case-studies. In the former case, we present an end-to-end and unified framework that consists of three phases, including data preprocessing, representation learning, and prediction. It achieves significant performance improvement in comparison to the best baseline algorithm (88 percent vs. 80 percent). In the latter case, we present a deep reinforcement learning based framework for bitrate adjustment. Evaluating the performance with a real wireless dataset, we show that the perceived video QoE average bitrate, rebuffering time and bitrate variation can be improved significantly.

A compact and broadband circular TE01-mode oversized deformed waveguide bend for high-power transmission line is proposed in this article. In order to obtain a circular TE01 mode with high purity output, a deformed waveguide structure, entitled quad-polar waveguide, which can destroy the degeneration between the TE01 and TM11 modes and weak mode conversion inside waveguide bend is introduced. The characterization of quad-polar waveguide and its influence of deformation on the mode spectrum are analyzed. The mode coupling coefficients of quad-polar waveguide are theoretically deduced to investigate the mode conversion inside the waveguide bend. Based on the multimode coupling theory, a broadband oversized waveguide bend with propagation efficiency over 95% from 27.6 to 34.1 GHz is designed. A prototype is fabricated and measured. The average transmission efficiency is over 93% according to the S-parameter measurement. The TE01 mode with high purity output is demonstrated by the near-field test. The high-power performance is investigated by connecting it with a gyrotron traveling-wave tube (gyro-TWT), and the waveguide bend works stably under a maximum output power of 140 kW. In addition to high power and broadband, the proposed waveguide bend features compact, simple structure, and easy to machine.

A Ku / Ka -band oversized waveguide bend, transmitting the power of TE01 mode at Ka -band and TE11 mode at Ku -band, is designed for the high-power transmission line. To suppress the generation of parasitic modes, a waveguide bend based on the elliptical waveguide is used to minimize the coupling capacity between the operating modes and the undesired modes. The mode coupling rules inside the elliptical waveguide bend are investigated. The optimized parameters, including the orientation of bend plane, the bend radius, and the eccentricity are chosen according to the analysis results. The calculation results show that the transmission efficiency of the TE01 mode is over 95% from 26 to 32 GHz, while the transmission efficiency of the TE11 mode is over 98.5% from 10 to 20 GHz. To validate the design, a prototype is fabricated and measured. Compared with the calculated results, the measured transmission efficiency has a 4% and 5%–6% drop in the Ka -band and Ku -band due to ohmic loss. The high output mode purity of the waveguide bend is verified by the near-field measurements.

Analysis of C.elegans by droplet microfluidics has been widely used in study of locomotive behavior responses to neurotoxicity due to the capacity of high-throughput manipulating single cells. However, it has been difficult to manipulate droplets flexibly and actively on account of the limitation of the dimension of individual C. elegans droplets. In this study, a novel MiDMS (Micro-injection Droplet Microfluidic System) was proposed, which consisted of three parts: single C. elegans droplet generator, droplets drug micro-injection channels and drug-incubation observation array. Individual C.elegans droplets were produced initially by regulating the flow rates between oil and water phase as well as the concentration of C.elegans in suspension. Then, the drug solution was precisely injected into each C.elegans droplet, which by electricity induced surface tension of droplet changing. In addition, the effect of neurotoxic Cu2+ on locomotive behavior of C. elegans was evaluated at single cell resolution. The results showed that the neurotoxicity induced behavioral disorder of the C. elegans was more obvious with the increase of Cu2+ concentration or treatment time, and these dose-effect and time-effect relationship in MiDMS were similar as in petri dish. This study will provide a powerful platform for the study of the response of C. elegans to quantitative drug at single cell resolution.

Purpose The high-intensity focused ultrasound (HIFU) ablation of tumors is inseparable from synergistic agents and image monitoring, but the existing synergistic agents have the defects of poor targeting and a single imaging mode, which limits the therapeutic effects of HIFU. The construction of a multifunctional biological targeting synergistic agent with high biosafety, multimodal imaging and targeting therapeutic performance has great significance for combating cancer. Methods Multifunctional biological targeting synergistic agent consisting of Bifidobacterium longum (B. longum), ICG and PFH coloaded cationic lipid nanoparticles (CL-ICG-PFH-NPs) were constructed for targeting multimode imaging, synergistic effects with HIFU and imaging-guided ablation of tumors, which was evaluated both in vitro and in vivo. Results Both in vitro and in vivo systematical studies validated that the biological targeting synergistic agent can simultaneously achieve tumor-biotargeted multimodal imaging, HIFU synergism and multimodal image monitoring in HIFU therapy. Importantly, the electrostatic adsorption method and the targeting of B. longum to tumor tissues allow the CL-ICG-PFH-NPs to be retained in the tumor tissue, achieve the targeting ability of synergistic agent. Multimodal imaging chose the best treatment time according to the distribution of nanoparticles in the body to guide the efficient and effective treatment of HIFU. CL-ICG-PFH-NPs could serve as a phase change agent and form microbubbles that can facilitate HIFU ablation by mechanical effects, acoustic streaming and shear stress. This lays a foundation for the imaging and treatment of tumors. Conclusion In this work, a biological targeting synergistic agent was successfully constructed with good stability and physicochemical properties. This biological targeting synergistic agent can not only provide information for early diagnosis of tumors but also realize multimodal imaging monitoring during HIFU ablation simultaneously with HIFU treatment, which improves the shortcomings of HIFU treatment and has broad application prospects.

The rotating packed bed (RPB) reactor with a lab-scale mesh-pin rotor (MPR) displays the great potential for the chemical processes with viscosity reactants or solid products. However, the scale-up...

A systematic scale-up study on a rotating packed bed (RPB) reactor is essential before the industrial application. However, the mass transfer and application performance of the RPB reactor with a s...

The work herein employed COMSOL Multiphysics simulation and experiment to study the temperature distribution of water in a specially designed cylindrical microwave (MW) reactor with two magnetrons....

An investigation of the single-frequency iteration method for synthesizing mode converter is taken, and the results show that the synthesized structure has an almost constant perturbation period, which limits the bandwidth of the mode converter. Therefore, a multifrequency iteration method based on variable perturbation periods is proposed to design a broadband oversized TE01-to-TE11 mode converter in this article. To avoid the interference among the perturbation periods corresponding to different frequencies, a weight function is introduced to separate these periods from each other. Using the proposed method, a TE01-to-TE11 mode converter is designed with the conversion efficiency over 95% in the range of 32.5–36.2 GHz (the relative bandwidth of 10.77%). To validate the performance of the proposed mode converter, a prototype is manufactured and measured. In the S-parameters measurement, an average conversion efficiency exceeding 93% and an average ohmic loss near 3% are obtained in the range of 32.3–36.2 GHz. The high purity of circular TE11 mode is demonstrated at the output of the fabricated mode converter according to the measured field patterns.

A new topology to excite circular TE02 mode for studying of gyrotron traveling-wave tube (gyro-TWT) is presented. The mode generator consists of a rectangular TE10 to cross waveguide TE44 mode converter and a cross waveguide TE44 to circular TE02 mode converter. To obtain a high-purity TE02 mode output and make the generator compact, a cross waveguide with sidewall coupling apertures and a novel mode transition section with metal diaphragm are introduced. The proposed mode generator is fabricated and measured. A good agreement between simulation and measurement is obtained, and the 1-dB bandwidth from 28 to 34 GHz is obtained in back-to-back test. The angle-independent transmission demonstrates high mode purity and the presence of TE02 mode confirmed by the field pattern measurement. The mode exciter features high mode purity, broad bandwidth, and is easy to be fabricated, which can be applied to cold-test experiments of gyro-TWT components and the high power transmission line devices.

Liquid dispersion by impacting on wire mesh benefits many mass transfer processes. However, most of studies focused on the dispersion behaviors of liquid impacting on a one-layer wire mesh. In this...

In this paper, we have introduced a compact eight-element antenna array for triple-band MIMO (multi-input multi-output) operation in 5G (fifth generation) mobile terminals, which consists of two symmetric four-element sub-arrays disposed, respectively, along two long side-edges of the system ground plane of the mobile terminal. This antenna element can operate at two dual-wideband of 3250-3820 MHz and 4790-6200 MHz with three resonance frequencies which can fully cover 5G NR (New Radio) BandN78 (3300-3800 MHz), China 5G-Band of 4800-5000 MHz and LTE Band-46 (5150-5925 MHz). The main parameters that characterize the performance of the proposed MIMO antenna system, such as bandwidth, reflection coefficient, isolation (more than 10.5 dB), total radiation efficiency (more than 43%), ECC (envelope correlation coefficient, less than 0.12) and CC (channel capacity, 34.9-37.6 bps/Hz), are analyzed and presented in this paper. Besides, the effects of single-hand and dual-hand on performance of the MIMO antenna system are also discussed. The structure of antenna element is only 15 mm × 3 mm (0.175 λ0 × 0.035 λ0, λ0 is the free-space wavelength at the frequency of 3.5 GHz) with a very small ground clearance of 13 mm × 2 mm on the main board of the proposed mobile terminal. The antenna system has the possibility to be used in 5G mobile terminals with triple-band operation, narrow frame and large display. The corresponding antennas prototype is fabricated and measured; and a quite good agreement between simulation and measurement is obtained.

Device fingerprinting is a crucial part in the Internet of Things applications. Existing device-fingerprinting solutions either ignore the influence of the type of network traffic or separately learn a fingerprinting model for each traffic type. This often leads to suboptimal solutions, especially when training data are limited. Considering that the data distributions of different traffic types may be different but related, we propose a novel multitask learning method to learn the fingerprinting models for several traffic types simultaneously. Specifically, we first design a system for device fingerprinting using the popular $k$ -nearest neighbor (KNN) approach. Then, a novel distance metric learning (DML) algorithm termed online multitask metric learning (OMTML) is developed to improve the distance estimation in our system. OMTML enables the models describing different traffic types to help each other during the metric learning procedure, and thus improving their respective accuracies. OMTML can also be updated adaptively, and the updating process is efficient. The experimental results show that the proposed KNN-based system outperforms the artificial neural network (ANN)-based counterpart significantly. Besides, the comparisons of our OMTML and other representative online and multitask DML approaches demonstrate both effectiveness and efficiency of the proposed metric learning method.

Solar energy has developed rapidly in recent years, and its impacts on climate have been revealed mainly through model simulations and limited field observations. However, the representation of solar plants in these models is highly simplistic and does not account for dynamical effects, which may pose risks under the simulations for tracking photovoltaics (PV). To make a more comprehensive assessment of the PV-induced climatic impacts, it is relevant to further develop a more sophisticated PV module based on the observed PV-induced impacts from specific cases. To remedy the deficiencies in the existing PV energy models, the newly sophisticated PV module established in this paper includes both the land surface radiation balance, sensible heat balance and the surface physical dray process over the locations of PV plants. It is then used to simulate the local climatic impacts of PV plants through three parallel sensitivity experiments. Comparison analysis between control run and two PV installation scenarios showed obvious changes in the 10-m wind speed, land surface temperature, and 2-m specific humidity were found locally over the locations of PV plants during both the warm and cold periods. The magnitudes of these changes are positively related to the installed capacity of the PV plants, but are much smaller than the natural climate variations. It is expected that the observation-based PV module established in this paper is a meaningful attempt for the model simulation on this field.

In heterogeneous ultra-dense networks (HUDNs), load balancing is always considered by offloading users from the macro base station (MBS) tier to the small base station (SBS) tier, to alleviate the data traffic of the MBS tier, while it causes a serious problem that the offloaded users will suffer strong interference from the MBS tier, and hence the signal-to-interference ratio (SIR) is in low region for the offloaded users. In order to improve the performance of these offloaded users, an interference mitigation scheme based on resource partitioning is employed in the literature. Specifically, a fraction of resource blocks (RBs) is reserved for the offloaded users, and then the SIRs of these users will be enhanced because there is only interference from the SBS tier. In summary, the combination of offloading and resource partitioning is called joint offloading and resource partitioning scheme, which has been investigated in the HUDNs built on the 2D space, while it has rarely been deliberated in 3D HUDNs that are used to model the scenario of high-rise buildings. Moreover, a two-tier 3D HUDN is proposed in this paper, and the MBS and SBS tiers are modeled as two independent Poisson point processes. Then, the SIR and rate meta distributions, which are used to characterize the fraction of users that achieve a desired link reliability given SIR or rate thresholds, are formulated for the proposed 3D HUDN. Lastly, numerical results show that with the usage of the joint offloading and resource partitioning scheme, the performance of the proposed 3D HUND can be significantly improved.

In this work the crystal structure and bandgap in the Cu3+δIn5Te9 material system were engineered through modifying the copper vacancy concentration (Vc). The results reveal that the crystal distortion parameter (ψ) increases as the Vc value decreases, which plays a fundamental role in enhancing the phonon scattering, thereby reducing the lattice part (κL) to the minimum value 0.21 W K−1 m−1 at ∼830 K. Although the electrical properties degrade due to the reduced Hall carrier concentration (nH) caused by the widened bandgap (Eg) as the Vc value increases, the mobility (μ) increases. As a consequence, the thermoelectric performance remarkably improves with a highest ZT value of ∼1.0 for the sample Cu3+δIn5Te9 (δ = 0.1). This value doubles that of the pristine Cu3In5Te9. The work gives insight into the potential phonon scattering in the distorted crystal structure in Cu-ternary systems and sheds some light on the design of high performance thermoelectric materials.

Quasi-homogeneous catalytic hydrogenation benefits from the absence of intraparticle diffusion in the catalyst with the gas–liquid–solid system. However, it still suffers from the gas–liquid mass-t...

An Al2O3-coated stainless steel wire mesh packing was prepared, aiming to serve as the monolithic catalyst support applied in a rotating packed bed (RPB) reactor. Before the application, the wetting behavior and gas–liquid mass transfer performance of Al2O3-coated wire mesh packing were investigated in this work. The results showed that the Al2O3-coated stainless steel fiber had on average 18.8% longer liquid spreading length compared with the uncoated stainless steel fiber. The gas–liquid effective interfacial area (ae) and the volumetric liquid-side mass transfer coefficient (kLae) of the RPB with Al2O3-coated wire mesh packing were on average 25.9 and 45.7% higher than those with uncoated wire mesh packing, respectively. The Al2O3-coated wire mesh packing has great prospects for the catalytic reactions in the RPB reactor by providing double functions of mass transfer intensification and the monolithic catalyst support.