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(1-x)BiScO3-xPbTiO3 (BS-PT) ceramics have excellent piezoelectricity and high Curie temperature at its morphotropic phase boundary (x=0.64), so it is a promising piezoelectric material for fabricating high temperature ultrasonic transducer (HTUT). Electric properties of 0.36BS-0.64PT ceramics were characterized at different temperature, and a HTUT with the center frequency of about 15 MHz was designed by PiezoCAD based on the measuring results. The prepared HTUT was tested in a silicone oil bath at different temperature systematically. The test results show that the HTUT can maintain a stable electrical resonance until 290 °C, and get a clear echo response until 250 °C with slight changes of the center frequency. Then a stepped metal block submerged in silicone oil was imaged by the HTUT until 250 °C. Velocity of silicone oil and axial resolution of the HTUT at different temperature were calculated. The results verify the capability of 0.36BS-0.64PT based HTUT for high temperature ultrasonic imaging applications.

This article has presented a unified electrothermal behavior modeling method for both silicon carbide (SiC) metal oxide semiconductor field effect transistor ( mosfet ) and gallium nitride (GaN) high electron mobility transistor (HEMT). The electrothemal behavior of these two kind of devices in both the first and the third quadrant is accurately modeled with serval compact equations. A modeling data and optimization algorithm-based parameter extraction method have been proposed to replace the previous time consuming and labor intensive one. The proposed parameter fitting algorithm is a genetic algorithm and Levenberg–Marquardt combined optimization algorithm possessing the advantages of global optimization and fast convergence speed, and modeling data can come from both datasheets and measurement. The correctness and accuracy of the proposed modeling method has been verified by simulation and experiment result. Meanwhile, it has been proved that the proposed modeling method is applicable to several commercially available SiC mosfet s and GaN HEMTs.

In order to obtain an ultrasonic transducer (UT) with ultra-broad bandwidth (BW), a multilayer stairstep piezoelectric structure (MSPS) is designed and fabricated. Based on the theoretical computation, the relationship between the resonant frequency and thickness of the piezoelectric layer is obtained. The designed MSPS includes 15 layers from center to side, and its frequency range is 5–22 MHz. The finite element method (FEM) based PZFlex software is used to predict the performance of UT with the designed MSPS, and the thickness of each layer is optimized according to the simulation results to achieve the ultra-broad-BW UT. The UT with the designed MSPS is fabricated and systematically characterized. The measured results show that the fabricated UT has a center frequency of 10.54 MHz and a −6 dB BW of 121%, which agree well with the simulation results (11.75 MHz and 140%). The MSPS has significant potential in UT applications.

This paper investigates a novel electrochemical enzyme-free glucose sensor based on bimetallic PtNi materials. Pt and Ni layer were sputtered on the substrate and then annealed to form bimetallic PtNi materials, which served as sensitive materials for glucose detection. The effect of annealing temperature on the performance of enzyme-free glucose sensors had been studied deeply. Using micro-electromechanical systems (MEMS) technology, a monolithic enzyme-free glucose sensor was fabricated, which integrated with working electrode (WE) and counter electrode (CE) on a chip. The electrochemical results demonstrate that the device exhibits outstanding sensitivity and selectivity for glucose detection, achieving a maximal sensitivity of 1618.15 µA mM−1 cm−2 in the range of 0–10 mM with a low detection limit of 8.76 µM. The sensor also shows its practical application for glucose detection in human blood serum. Due to its performance and fabrication process, the enzyme-free glucose sensor is therefore well suited for glucose detection and manufacture together with other integrated circuits on a single silicon wafer, which shows potentials in implantable microelectronic systems.

Textile-based flexible Lithium-Ion Batteries (LIBs) show promising mechanical flexibility that is appealing for a wide variety of wearable and flexible electronic applications. The flexibility of flexible LIBs nowadays is still limited. In addition, their power performance is too low to enable high-speed charging, due to the low conductivity of the textiles. Here, we develop highly electrically conductive metallic fabrics, which are fabricated by coating nanostructured Ni or Cu (nano-reliefs) on woven cotton fabrics, as current collectors to enable crumpled, high-power, and safe wearable LIBs. The nanostructured metal coating not only effectively increases the contact area between current collectors and active materials, but also shortens the charge carrier transport paths, so that LIBs constructed on these nanostructured metallic cotton fabrics exhibit a high power density of 439 W/L and superior electrochemical stability under various mechanical deformations including folding, twisting, squeezing, and impacting. This type of nanostructured metallic textile is highly desirable for portable and wearable electronic applications.

The performance of piezoelectric ultrasonic transducer (PUT) is obviously affected by its matching layer. An intelligent optimization method for matching layer of PUT is proposed to fabricate PUT with high performance. The original data, including matching layer and performance parameters of PUT, is obtained by PiezoCAD software. Then the neural network models are established to mathematically characterize the effect of matching layer on the performance of PUT. The optimization criteria for PUT is constructed according to its performance requirements, such as center frequency (CF), bandwidth (BW) and pulse width (PW). In order to decrease the material cost, the thicknesses of matching layers are also considered in the optimization criteria. The modified particle swarm optimization algorithm is used to optimize the thicknesses of matching layers (Ag-epoxy and Parylene C). According to the designed performance, the optimized thicknesses of Ag-epoxy and Parylene C are about $54~\mu \text{m}$ and $21~\mu \text{m}$ , respectively. Based on the optimized thicknesses of matching layers, the simulated and experimental performances of PUT well agree with the designed ones. In addition, compared to the traditional quarter-wavelength theory, the proposed method can effectively decrease the materials cost. The −6dB BW and PW of PUT fabricated according to the optimized parameters are about 68.5% and $0.123~\mu \text{s}$ , which are better than that fabricated according to the quarter-wavelength theory (about 50% and $0.147~\mu \text{s}$ ).

In order to effectively and flexibly control acoustic pattern, an efficient optimization design method of acoustic liquid lens (ALL) is developed by the frame of particle swarm optimization (PSO) algorithm. The ALL is composed of ethanol and dimethicone, and its parameters include ethanol concentration (EC), volume fraction of dimethicone (VFD), and total volume (TV). Based on the established finite element model and orthogonal design method, the data of acoustic pattern and ALL can be obtained by using COMSOL Multiphysics. Based on the simulation data, the neural network models are constructed to characterize the relationship between the parameters of ALL and the performance of acoustic pattern. The optimization design criteria of ALL are constructed based on the performance parameters of acoustic pattern, including focal distance (FD), transverse resolution (TR), and longitudinal resolution (LR). Based on the optimization criteria, the modified PSO algorithm is utilized to optimize the design parameters of ALL in the developed method. According to the desired FD, TR, and LR of acoustic pattern (20, 1, and 17 mm), the optimized EC, VFD, and TV of ALL are about 0.838, 0.165, and 164.4 $\mu \text{L}$ . The performance parameters of acoustic pattern verified by simulation and experiments agree with the desired ones. In addition, using 6 MHz ultrasonic transducer with the optimized ALL, the ultrasonic imaging of tungsten wires and porcine eyeball further demonstrates the effectiveness and feasibility of the developed method.

Acoustic hologram enable the capability in the acoustic pattern control and drive many applications of ultrasound. However, hologram has not been applied to ultrasound imaging because the medical application of acoustic holograms is limited owing to the sound reflection and scattering at the acoustic holographic surface and its internal attenuation. In this study, we propose an acoustic holographic computing method and present a disc-shaped hologram with a central hole comparing with a conventional hologram using the iterative angular spectrum approach. The results show that the transducer with hole hologram achieves the required focusing effect with the full width at half maximum about $1.5\lambda $ , high sensitivity increased by 92.7%, and a low two-way insertion loss with −15.8 dB compared to conventional hologram. Pulse-echo and ultrasonic imaging are achieved by a transducer with two holograms which shows new applications of acoustic hologram in ultrasound.

Due to the low efficiency of traditional design method, an efficient optimization design method is developed to design and fabricate high-performance ultrasonic transmitting transducer (UTT) based on PiezoCAD software and particle swarm optimization (PSO) algorithm. Based on the data of design and performance parameters of UTT obtained by PiezoCAD software, the genetic algorithm-based back-propagation neural networks (GA-BPNNs) are established to describe their mapping relationship. The optimality criterions are established based on the performance parameters including center frequency (CF) and maximum echo amplitude (MEA). Then, based on the established GA-BPNNs and optimality criterions, the optimization design method of UTT is developed under the framework of PSO algorithm. According to the desired performance, the design parameters of UTT, including the thickness and diameter of PZT-4 (Pb(Zr x Ti1-x)O3), the acoustic impedance of backing, are optimized by the developed method, and they are 2 mm, 30 mm and 3 MRayl, respectively. Based on the optimized design parameters, the CF and MEA simulated by PiezoCAD are 1.05 MHz and -45.1 dB, which are in good agreement with the designed ones (1 MHz and -45 dB). In addition, the CF of the fabricated UTT is 1.07 MHz, and its insertion loss is -7.2 dB at 1.075MHz, which implies that the fabricated UTT has excellent performance. Therefore, the developed optimization design method is effective to fabricate high-performance UTT.

In order to study the effects of loading rates on the strength and failure of high-water-content material, the loading rates of 0.1, 0.5, 1, 2 and 5 mm/min were selected to conduct uniaxial tests o...

To promote the engineering applications of high water backfill materials (HWBM) in mining, a series of experiments are performed to investigate the effects of the direct current (DC) electric field on the mechanic properties and electrical resistivity of HWBMs. Based on X-ray diffraction (XRD) and scanning electron microscopy (SEM) investigations, the influence of electrochemical treatment on the hydration products and the microstructure of the HWBM was studied. The results show that the peak strength, elastic modulus, deformation modulus and electrical resistivity of the HWBM samples all first increased and then decreased with the increasing of the potential gradient, and the peak points appeared when the potential gradient was 0.2 V/cm. The anisotropy of content of ettringite and calcium silicate hydrates (C–S–H) increased betweent the anodic and cathodic regions of samples. Meanwhile, microstructure in the anodic region of the samples was more stable after electrochemical treatment, which indicates that the different variation of mineralogical compositions and microstructures in different regions of the samples are the primary factors affecting the mechanic properties and electrical resistivity of the HWBM. Therefore, the electrochemical method is a potential technology to modify the engineering properties of the HWBM.

The emerging two-dimensional ferromagnetic materials present atomic layer thickness and a perfect interface feature, which have become an attractive research direction in the field of spintronics f...

A series of iron-encapsulated hierarchical ZSM-5 zeolites with nanosheet-assembled structure were designed and successfully fabricated, and their catalytic performance was investigated for the sele...

Ultrasonic transducers with broad bandwidth are considered to have high axial resolution and good ultrasound scanning flexibility for the clinical applications. The limitations of spatial resolution due to bandwidth are of great concern in ultrasound medical imaging. The method of acoustic impedance matching between the piezoelectric element and medium is commonly used to obtain broad bandwidth and high resolution. In this study, an optimized backing layer design was proposed to broaden the bandwidth by adding a tunable acoustic impedance matching layer of backing (AIMLB) between the backing layer and the piezoelectric ceramic element. The Mason equivalent circuit method was used to analyze the effect of the backing material composition and its structure on the bandwidth of the transducer. The optimized transducer was simulated using the finite-element method with the PZFlex software. Based on the PZFlex simulations, a 20-MHz ultrasonic transducer using the AIMLB with a bandwidth of approximately 92.29% was fabricated. The experimental results were in good agreement with the simulations. The ultrasonic imaging indicated that the designed ultrasonic transducer with an additional AIMLB had high performance with good imaging capability.

Zinc-blende CdS nanoplatelets with atomically flat and very large {100} basal planes terminated solely by one type of element (either Cd or S atoms) are synthesized. Optical spectroscopy, X-ray diffraction, X-ray absorption, and transmission electron microscopy confirm that the surface structures of newly developed S-terminated CdS nanoplatelets are at least as well-defined as the original Cd-terminated nanoplatelets. Band gaps of the nanoplatelets are found to depend on not only the quantum-confined dimension (thickness) but also the nature of the surface termination. The facet structure dictates the packing of the ligands (carboxylate for Cd-terminated nanoplatelets and alkyl for S-terminated nanoplatelets), which causes a difference in the lattice strain and significantly affects the optical spectral width. Experimental and theoretical results reveal that engineering the exciton spatial distribution by the tailored synthesis of semiconductor nanocrystals with a precisely controlled surface structure is fully possible, which should open a new door for delivering the long-promised potential of semiconductor nanocrystals.

Facet-dependent on-surface reactions are systematically studied on zinc-blende CdSe nanoplatelets with atomically-flat {001} basal facets and small yet non-polar side facets. The on-surface half-reactions between the surface Se sites and Cd carboxylates in the solution are qualitatively equivalent to those on the spheroidal counterparts. Conversely, the on-surface half-reactions between the surface Cd sites and the activated Se precursors in solution show a strong facet-dependence, which includes three distinguishable stages. In the first stage, the Se precursors adsorb onto the small and non-polar side facets of the nanoplatelets. The second stage is initiated by the adsorbed Se precursors at the side-basal plane edges and proceeds from the edges to the center of the basal planes in quasi-zeroth-order kinetics. In the third stage, the nanoplatelets are dismantled, which includes the creation of a hole in the middle and a build-up of thick edges.

The intermediate-temperature (473–973 K) deformation behavior of a nickel-based superalloy is researched by uniaxial tensile experiments. It is observed that the flow characteristics and the Portevin–Le Chatelier (PLC) effects are significantly affected by the thermo-mechanical parameters. The serrated flow features are obvious under the testing conditions. A stacked auto-encoders (SAEs) network model is proposed for predicting the flow behaviors of the researched superalloy. The architecture of the established SAEs model is optimized layer by layer. The best number of hidden layer is 3, and the nodes per hidden layer are 15, 20 and 50, respectively. The excellent prediction ability suggests that the developed SAEs model can well reconstruct the intermediate-temperature flow behavior involving the PLC effects of the researched superalloy.

Fiber reinforced polymer (FRP) bars, as alternatives of steel bars, are encouraged to be utilized in concrete construction due to the properties of both corrosion resistance and high tensile strength. In this paper, smart aggregate (SA) transducers, which can be used as both actuator and sensor, are employed to identify the structural damage mechanism of basalt-FRP (BFRP) bars reinforced concrete beams. Time reversal method is adopted for increasing the signal-to-noise ratio (SNR), which is aimed at obtaining clear amplitude of focused signal. Those methodologies are applied to conduct a further study of the structural mechanism of BFRP reinforced concrete flexural components. The experimental results reveal that the cracking and failure position of the concrete beam reinforced with BFRP bars can be located and the corresponding loads can be identified according to signal change when different crack appears. The stiffness degradation of BFRP bars reinforced concrete beams can be effectively expressed and the deflection can be accurately predicted by acquiring amplitude of focused signals in the overall zone. Additionally, it has been recognized that the damage process and mechanism of BFRP reinforced concrete beams can be accurately evaluated using those SA transducers and the status of those structural components also can be monitored effectively.

This study investigates the interply hybridization of carbon fibre reinforced polymer (CFRP) composite laminate to improve the flexural performance and cost efficiency. Carbon layers were replaced partially by basalt and/or glass fibres to explore the effects of hybrid ratio and stacking sequence on the flexural behavior and material usage. Hybrid laminates were manufactured by vacuum assisted resin transfer molding (VARTM) process. Three-point bending tests were carried out to characterize the flexural properties and failure mechanisms of the hybrid composite laminates. The fracture surfaces were examined by scanning electron microscopy (SEM). The results showed that flexural strength and modulus of the hybrid laminates decreased with the increase in the hybrid ratio of basalt fibres ranging from 0 to 50%; however negligible effects on flexural properties were observed when hybrid ratio increased further up to 75%. For the hybrid samples, a higher flexural modulus can be obtained by placing carbon layers on the both tensile and compressive sides symmetrically; and a higher flexural strength can be achieved by placing basalt or glass fibre through a sandwich-like stacking sequence with a hybrid ratio of 50%. The finite element modeling and classic laminate theory (CLT) analysis were also conducted through validation against the experimental results, which enabled to reveal the details of strain, damage and fracture under bending. The study exhibited a better material efficiency for glass/carbon hybrid laminates in terms of strength/cost and modulus/cost ratio; and the benefits of such cost efficiency of hybridization were discussed in depth for potential engineering applications.

Fiber-based photonic nanostructures with potential employment in nano/microscale optical devices are attracting a growing interest. In this work, we report on the emission features of polymer fibers made of 4(dicyanomethy-lene)-2-tert-butyl-6(1,1,7,7-tetramethyljulolidyl-9-enyl)4H-pyran (DCJTB) doped polyvinyl pyrrolidone (PVP) with diameters in the range of 1.5–2 μm, realized by electrospinning method. In the fibers, silver nanoparticles (Ag NPs) are introduced as scatters, where multimode random lasing action is achieved. Experiments indicate that strengthened lasing shot has been triumphantly realized in the existence of metal Ag NPs. By optimizing the ratio of Ag NPs to DCJTB during the process of the preparation, random lasing emission has been realized with much cut down thresholds to 0.55 mW cm−2. The microscopic resonators may be shaped both by randomly oriented polymeric fibers and multiple scattering of Ag NPs which offer special opportunities to design multiple light scattering and random laser. Besides, the localized surface-plasmon resonance (LSPR) of Ag NPs is excited, which couples with output emission of DCJTB to improve the lasing efficiency. This system is a promising candidate for the coming growth of all-plastic, micro- to macroscale optical tables for signal transmission and processing.

In this study, a strategy based on the particle swarm optimization (PSO) algorithm is developed to control the microstructures of a Ni-based superalloy during hot forging. This strategy is composed of three parts, namely, material models, optimality criterions, and a PSO algorithm. The material models are utilized to predict microstructure information, such as recrystallization volume fraction and average grain size. The optimality criterion can be determined by the designed target microstructures and random errors. The developed strategy is resolved using the PSO algorithm, which is an intelligent optimal algorithm. This algorithm does not need a derivable objective function, which renders it suitable for dealing with the complex hot forging process of alloy components. The optimal processing parameters (deformation temperature and strain rate) are obtained by the developed strategy and validated by the hot forging experiments. Uniform and fine target microstructures can be obtained using the optimized processing parameters, which indicates that the developed strategy is effective for controlling the microstructural evolution during the hot forging of the studied superalloy.

The precipitation behavior of α phase in a β-quenched Ti-55511 alloy during high-temperature compression is investigated. The influences of deformation parameters on the flow characteristics, microstructural evolution, as well as the precipitation behavior of α phase, are discussed. Results show that the flow stress features and the dominant softening mechanism are sensitive to the deformation parameters. At low strain rates or high deformation temperatures, the main softening mechanism is dynamic recovery. But, the dynamic recrystallization becomes the dominant softening mechanism at high strain rates or low temperatures. At low strain rates, the continuous strengthening, induced by the pinning effect of α precipitates, happens at the late period of deformation. Distribution of α precipitates is not greatly affected by deformation parameters. In the region near β grain boundary, α precipitates are densely distributed with few orientations. While in the central region of β grain, the α precipitates are distributed a bit more sparsely with several scattering orientations. In addition, with increasing deformation temperature, the content, aspect ratio and size of α phases decrease. However, with increasing strain rate, the content, aspect ratio and size first increase and then decrease. Furthermore, the peak value of aspect ratio appears at 0.01 s−1.

To obtain the designed target microstructures of an aged superalloy during isothermal forging, a multi-level processing parameters optimization method is developed based on particle swarm optimization (PSO) algorithm. In the developed method, the accurate material models are used to characterize the microstructural evolution. Based on the designed target microstructures, the global and local optimality criterions are constructed to alternately optimize global and local multi-level processing parameters by the PSO algorithm with a linear decreasing inertia weight strategy. The optimized initial volume fraction of δ phase (δVF), deformation temperature and strain rate are 12.95%, 1000 °C and 0.001 s−1, respectively. According to these optimized parameters, the recrystallization volume fraction, average grain size and δVF are 100%, 11.2 µm and 2.1%, respectively, which well agree with the designed targets. Additionally, the processing parameters optimized by the developed method and traditional processing maps are compared. It is found that the developed method is more effective to control microstructures for the studied superalloy.

Nickel (Ⅱ)-ethylenediaminetetraacetic acid (Ni-EDTA) complexes are widely present in electroplating effluents. Owing to its chemical stability, Ni-EDTA is hardly removed in traditional Fenton/Fenton-like processes with conventional iron (Fe)-based catalyst. In this study, oxygen vacancies were introduced into our highly efficient and novel Fe3O4@γ-Al2O3 catalysts using Cu doping for Ni-EDTA decomposition in Fenton-like system. Without noble-metal cocatalyst, the introduction of oxygen vacancies in Cu-doped Fe3O4@γ-Al2O3 catalysts exhibit excellent Fenton-like activity even in neutral or alkaline conditions. Experimental results revealed that, without the aid of extra energy, Ni-EDTA complexes could be effectively decomposed over oxygen vacancies-based catalyst. Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), oxygen temperature-programmed desorption (O2-TPD), and hydrogen temperature-programmed reduction (H2-TPR) were used to get a deep insight into the decomposition mechanism. Additionally, by employing the Al-containing support, stable layered double-hydroxide phases of NiAl could be formed, indicating that a synergy of oxidation and adsorption could simultaneously take place, which led to the recovery of released Ni2+ ions and also reduction in secondary pollution. To investigate the decomposition process of Ni-EDTA over oxygen vacancies-based catalyst, liquid chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry (LC-MS/MS) was employed to identify the generated intermediates, and thus, a plausible decomposition pathway was successfully conceived.

Developing highly efficient and inexpensive photocatalysts without noble metals, yet remarkably enhancing hydrogen production and Cr(VI) reduction activity, is highly needed. Here, the effective photocatalytic H2 evolution under visible light from an Eosin Y (EY)-sensitized (P, Mo)-g-C3Nx system by avoiding any noble metal co-catalyst is reported by the first time. Meanwhile, the optimized sample also displays the excellent performance in photocatalytic hexavalent chromium (Cr(VI)) reduction. In addition, this composite exhibits delectable stability for photocatalytic activities, no significant decay of activity is being observed after 16h reaction for photocatalytic H2 evolution (8h for Cr(VI) reduction). It is believed that this work will open up a new route for fabricating high-performance and inexpensive photocatalysts for hydrogen production and Cr(VI) reduction.

This study investigated the effect of transverse pre-impact damage on the load bearing capacity and failure behavior of square carbon fiber reinforced plastic (CFRP) tubes for axial crushing. The CFRP tubes were impacted transversely in different levels of impact energies to generate initial damage, and then the specimens were further crushed axially to evaluate the relation between transverse impact energies/positions and the residual axial crashworthiness. A finite element (FE) model was also developed to simulate the complex damage behavior of the CFRP tubes under these two different loading processes, based upon the continuum damage model (CDM) with user-defined material subroutine in Abaqus. A combined failure mode was observed in the transverse pre-impact tests, in which delamination was combined with partial or complete fiber breakage when increasing the impact energy from 10 J to 30 J. In the axial compression tests, two typical failure modes with circumferential fracture near the pre-impact position were identified for the damaged tubes, exhibiting significant difference from the progressive folding failure seen in undamaged tubes. Further, the damaged tubes yielded up to 38%, 58.5% and 58.3% reduction in terms of the peak load, mean load and energy absorption respectively in comparison with the specimens without pre-impact damages. It is also found that the residual crushing capacity decreased with increase in the transverse pre-impact energy; nevertheless the residual axial crushing properties were insensitive to single or double impacts on different circumferential positions. The failure modes of fiber breakage, delamination and matrix crack were investigated in detail by using the FE analysis.

This paper presents a combined experimental and numerical study on the dynamic response and failure mechanisms of honeycomb sandwich panels subjected to high-velocity impact by a spherical steel projectile. Impact tests were performed in a velocity range from about 70 to 170 m/s to investigate the effects of facesheet thickness, core height, cell wall thickness and cell size of honeycomb on the impact behaviour of sandwich panels. These geometric parameters were found to influence the impact performance mainly by changing the deformation and failure mechanisms of both sandwich facesheets. Moreover, the ballistic limit velocity and critical perforation energy of each sandwich configuration were obtained by numerical simulation. It was found that increasing facesheet thickness and reducing honeycomb cell size were two weight-efficient ways to enhance the perforation resistance of sandwich panels when the areal density exceeded a certain value. The projectile's penetration process into the sandwich panel and the associated energy absorbing mechanisms were analysed, the results of which showed that facesheets contributed most to energy absorption. Further numerical simulation was conducted to explore the influences of core stiffness and the thickness ratio of front to back facesheet. It was found that core stiffness had a significant effect on the deformation and failure initiation of front facesheet; more specifically, the front facesheet failed more easily due to stress concentration with the increase of core stiffness. When the total thickness of front and back facesheets remained constant, increasing the front-to-back thickness ratio led to higher damage resistance but greater deformation area on the front facesheet. Finally, a discrete optimisation was conducted to generate an optimal design of sandwich structure for achieving the highest specific energy absorption without perforation under a certain impact energy. The optimised sandwich panel exhibited an increase of 23.7% in specific energy absorption compared with the initial design.

An optimization design strategy is developed for ultrasonic transducer (UT) with multimatching layer to improve its performance. The piezoelectric equivalent circuit model is used to determine the optimization interval of matching layer, and the PiezoCAD software is used to simulate the performance of UT with multimatching layer. The neural network (NN) models are trained by the simulation data to characterize the relationship between the thickness of matching layer and performance of UT. Then, the multiobjective optimality criteria for UT is established based on its performance parameters, including center frequency (CF), −6 dB bandwidth (BW) and pulsewidth (PW). The thickness of matching layer is optimized by particle swarm optimization (PSO) algorithm. According to the designed performance, the optimized copper thickness and parylene thickness are about 17.76 and $23.05~\mu \text{m}$ , respectively. The simulation results of UT with the optimized multimatching layer well agree with the designed targets. Also, CF, −6 dB BW, and PW of the fabricated UT with the optimized multimatching layer are 5.672 MHz, 50.08%, and $0.295~\mu \text{s}$ , respectively, which nearly achieve the designed performance. In addition, the performance of UT with the optimized multimatching layer is much better than that of UT without matching layer. Moreover, compared with UT with single or double matching layers determined by the quarter wavelength theory, the UT with the optimized multimatching layer has better comprehensive performance. Finally, the fabricated UT with the optimized multimatching layer is used to measure the thickness of testing block, and the relative errors are all less than 1.0%, which implies that the optimized UT has excellent performance.

Summary Acoustic micro-beams produced by highly focused ultrasound transducer have been investigated for micro-particle and cell manipulation. Here we report the selective trapping of microspheres via the acoustic force using the single acoustical beam. The forbidden band theory of acoustic radiation force trapping is proposed, which indicates that the trapping of particles via the acoustic beam is directly related to the particle diameter-to-beam wavelength ratio as well as excitation frequency of the ultrasonic acoustic tweezers. Three tightly focused LiNbO3 transducers with different center frequencies were fabricated for use as selective single beam acoustic tweezers (SBATs). These SBATs were capable of selectively manipulating microspheres of sizes 5–45 μm by adjusting the wavelength of acoustic beam. Our observations could introduce new avenues for research in biology and biophysics by promoting the development of a tool for selectively manipulating microspheres or cells of certain selected sizes, by carefully setting the acoustic beam shape and wavelength., Graphical abstract, Highlights • Ultrahigh-frequency (≥100 MHz) ultrasonic transducer to manipulate microspheres • The broad bandwidth and highly focused transducer differentiate microparticles • FEA modeling and calculation indicate the force for selectively trapping • The forbidden band theory of acoustic radiation force is proposed for trapping, Ultrasound Technology; Biochemistry Methods; Biophysics

As an antineoplastic drug, methotrexate (MTX) is widely applied in cancer therapies; however it has potentially toxic activity, and thus the qualitative and quantitative determination of MTX is of great significance. In this paper, by using dopamine synchronously as a carbon and N source, N-doped hollow nanocarbon sphere (NHNC) hybrids were prepared via a simple self-polymerization method and used to construct a new electrochemical sensor for MTX. The prepared NHNC exhibits a uniform hollow nanostructure with high conductivity and electrocatalytic properties as well as large adsorption capacity and surface area, which are the key factors for improving the sensor sensitivity of MTX. For achieving highly sensitive determination of MTX, various conditions were optimized, and the final results show that the NHNC modified electrode has excellent sensing responses for MTX, and it has a wide linear range from 0.05 to 14.0 μM coupled with a low detection limit of 0.01 μM. Finally, studies on the reproducibility, stability and selectivity of the NHNC modified electrode show that the corresponding results are satisfactory.

Rare-earth-transition-metal (RETM) ferrimagnets have received great attention for their small magnetic moments and fast dynamics in the development of next-generation spintronic devices. Here, we study spin Hall magnetoresistance (SMR) in the RETM ferrimagnet and heavy-metal bilayers of ${\mathrm{Co}}_{1\text{\ensuremath{-}}x}{\mathrm{Tb}}_{x}/\mathrm{Pt}$. Anomalous temperature dependence of the SMR is observed, where the SMR changes nonmonotonically and has a valley next to the magnetization compensation temperature. Additionally, we find that the SMR varies significantly for different chemical compositions of ${\mathrm{Co}}_{1\text{\ensuremath{-}}x}{\mathrm{Tb}}_{x}$ alloys. These anomalous behaviors are interpreted as the dramatically altered spin polarization of the ${\mathrm{Co}}_{1\text{\ensuremath{-}}x}{\mathrm{Tb}}_{x}$ layer near the compensation point. By deducing spin polarization from the abnormal temperature dependence of SMR, we provide a convenient way to access spin polarization of the RETM ferrimagnets. These experimental results show implications for tunable spin-current sources of RETM ferrimagnets.

In order to improve the fabrication efficiency and performance of an ultrasonic transducer (UT), a particle swarm optimization (PSO) algorithm-based design method was established and combined with an electrically equivalent circuit model. The relationship between the design and performance parameters of the UT is described by an electrically equivalent circuit model. Optimality criteria were established according to the desired performance, then, the design parameters were iteratively optimized using a PSO algorithm. The Pb(ZrxTi1-x)O3 (PZT) ceramic UT was designed by the proposed method to verify its effectiveness. A center frequency of 6 MHz and a bandwidth of &minus, 6 dB (70%) were the desired performance characteristics. The optimized thicknesses of the piezoelectric and matching layers were 255 &mu, m and 102 &mu, m. The experimental results agree with those determined by the equivalent circuit model, and the center frequency and -6 dB bandwidth of the fabricated UT were 6.3 MHz and 68.25%, respectively, which verifies the effectiveness of the developed optimization design method.

The effective passivation of a sulfur electrode in Li-S pouch cells is addressed by increasing the discharging cutoff voltage from 1.6 to 2.0 V. This simple method can effectively suppress the generation of solid and insulated Li2S deposition while reserves the majority of capacity and improves the cyclic stability of Li-S pouch cells. Upon increasing the discharging cutoff voltage from 1.6 to 2.0 V, the Li-S pouch cell loses only 8% of the initial discharge capacity and remarkably promotes the capacity retention rate from 62.4 to 91.6% within 40 cycles at 0.05C. The analysis of electrochemistry and physics of a sulfur cathode demonstrates that the less Li2S deposition under the discharging cutoff voltage of 2.0 V can ensure fast reaction kinetics in Li-S pouch cells with high areal sulfur loadings and lean electrolyte. The mechanism of the passivation of a sulfur electrode is studied and discussed in detail. This brand new methodology may provide an effective approach to enhance the cyclic stability of a Li-S battery.

© 2020 Elsevier Ltd Basalt fiber composites have attracted increasing attention in recent years due to their advantages over carbon fiber composites in many aspects such as lower cost, environmental friendliness, superior heat resistance and ductility. Notches in structural components are unavoidable in practical applications. In the present study, the effects of notch shape and size on the tensile properties of basalt fiber laminates were investigated by experiment, finite element analysis and theoretical calculation. Specimens were prepared using laminates reinforced by plain woven basalt or carbon fiber fabrics and machined with an open circular hole or straight notch. Standard tensile tests were conducted and recorded using digital image correlation, aiming to measure the full-field surface strain. Continuum damage mechanics based finite element models were developed to predict stress concentration factors and failure processes of notched specimens. The characteristic distances of the stress criterion models were calibrated by the experimental results of un-notched and notched specimens so that failure of basalt fiber laminates with circular and straight notches could be analytically predicted.

The structural integrity of post-tensioning prestressed concrete structures with tendon ducts highly depends on the grouting quality in construction. This paper proposes a real-time approach to monitoring the grouting compactness in tendon ducts using the multi-sensing electro-mechanical impedance (EMI) method. When Lead Zirconate Titanate (PZT) transducers with different pre-selected dimensions are serially connected and mounted on a structure at distributed locations, each PZT provides unique resonance frequency coupled with the local structural physical property. Therefore, the impedance with multiple peaks of the serially connected multiple PZTs can be captured during a single measurement, which significantly simplifies the measurement procedure and reduces the data processing time. In addition, the wiring for the PZT sensors is also simplified. In this research, the feasibility of the proposed method was experimentally and numerically investigated to monitor the grouting compactness in a tendon duct specimen. The 3-dB mean absolute percentage deviation (MAPD) was applied to quantify the variations of the impedance signatures measured from five different grouting levels. Both experimental and numerical results verify the feasibility of using the proposed method for monitoring the grouting compactness in tendon ducts.

Aiming at the problem of large deformation and instability failure and its control of soft coal and soft roof roadway under intense mining, laboratory experiments, theoretical calculations, Flac3D numerical simulation, borehole peeping, and pressure observation were used to study the deflection characteristics of the deviatoric stress of the gas tailgate and the distribution and failure characteristics of the plastic zone in the mining face considering the strain softening characteristics of the roof and coal of roadway, and then the truss anchor cable-control technology is proposed. The results show the following: (1) The intense mining influence on the working face will deflect the peak deviatoric stress zone (PDSZ) of the surrounding rock of the gas tailgate. The influence distance of PDSZ is about 20 m in advance and 60 m in lag; the PDSZ at the gob side of the roadway is located in the range of 3–5.5 m from the surface of the coal pillar, while the coal wall side is mainly located in the range of 3–4.5 m at the shoulder corner and bottom corner of the solid coal. (2) The intense mining in the working face caused the nonuniform expansion of the surrounding rock plastic area of the gas tailgate. The two shoulder angles of the roadway and the bottom of the coal pillar have the largest damage range, and the maximum damage location is the side angle of the coal pillar (5 m). Angle and bottom angle of coal pillar are the key points of support control. (3) The plastic failure line of the surrounding rock of the gas tailgate is always between the inner and outer contours of the PDSZ, and the rock mass in the PDSZ is in a stable and unstable transition state, so the range of anchor cable support should be cross plastic failure line. (4) The theoretical calculations and numerical simulation results agree well with the drilling peep results. Based on the deflection law of the PDSZ and the expansion characteristics of the plastic zone, a truss anchor cable supporting system with integrated locking and large-scale support function is proposed to jointly control the roof and the two sides, which effectively solves the problem of weak surrounding rock roadway under severe mining deformation control problems realizing safety and efficient production in coal mines under intense mining.

To modify the mechanic properties of high water backfill material (HWBM) for its engineering application in mining backfill, a series of experiments were performed to investigate the effects of electrochemical treatment on the mechanic properties and electrical resistivity of the HWBM at the early age. Meanwhile, the effects of the potential gradient, power-on time, and water–cement ratio (W/C) on electrochemical modification efficiency were investigated. The results show that the uniaxial compression strength (UCS), elastic modulus, and deformation modulus of the HWBM all first increased and then decreased after electrochemical treatment with the increasing of the potential gradient and power-on time. However, for the HWBM with different W/C, the UCS and electrical resistivity both increased the HWBM except when the W/C was 3 : 1. The elastic modulus and deformation modulus of the samples both increased after electrochemical modification except when the W/C was 4 : 1. Additionally, there is a positive correlation between the UCS and electrical resistivity in HWBM samples. Therefore, it is proved that the electrochemical technology is a potential method for improving the physicochemical properties of the HWBM.

In this study, an optimization design method based on adaptive neuro-fuzzy inference system (ANFIS) and modified particle swarm optimization (PSO) algorithm is proposed to enhance the performance of high-frequency ultrasonic transducers (UTs). The optimization indexes include center frequency (CF) and −6 dB bandwidth (BW), and the design parameters (DPs) include thickness (TP) and size (SP) of piezoelectric layer, thicknesses of matching layers (Ag-epoxy and Parylene C). Based on simulated results, an ANFIS model is established to characterize the effect of DPs on the performance indexes (PIs). Optimization targets are set as CF of 30 MHz and BW of 65%, the modified PSO algorithm is adopted to optimize the design parameters of high-frequency UT. The optimized TP and SP are 110 μm and 5.2 mm. The optimized thicknesses of Ag-epoxy (TAE) and Parylene C (TPC) are 16 μm and 20 μm, respectively. Simulations and experiments of high-frequency UT are conducted based on the optimized DPs, the results well agree with the designed ones. The CF and the BW of UT fabricated by the developed method are 26.77(±0.02) MHz and 65.11(±0.06) %, while the CF and the BW of UT fabricated by the traditional method are 23.42 MHz and 51.4 %.

In virtue of higher thermal resistance, superior ductility, and lower cost than carbon fiber, basalt fiber has attracted extensive attention recently to be an alternative to reinforcement materials. Nevertheless, relatively fewer works have been reported on the mechanical properties of such fibers and their hybrid forms with other fibers available on the market. In this study, mechanical properties of carbon/basalt fiber reinforced epoxy hybrid composite were investigated through experimental, analytical and numerical methods. Seven symmetric composite laminates with different hybrid ratios and stacking sequences were fabricated by the vacuum assisted resin transfer molding (VARTM) technology and tested under tensile and bending loads, respectively. The test results showed that the stacking sequences had an evident influence on strength and flexural modulus, but less influence on tensile modulus. Tensile properties extracted from the experimental data exhibited good agreement with the results obtained from the analytical model. Further, the finite element analysis (FEA) was carried out in ABAQUS/Explicit through developing a VUMAT subroutine program to investigate the flexural properties in detail. The numerical simulation and experimental tests show good correlation for the flexural modulus. A modified analytical model was derived for predicting flexural strength by comparing with the FEA and experimental results. Both analytical model and numerical results are validated against the experimental results. In this study, scanning electron microscopy (SEM) study on the failed specimens revealed that use of ductile basalt fiber may to a considerable extent prevent cracks from propagation across the thickness and alter the failure modes from a no-kink pattern, commonly seen in pure carbon composites, to a kink band pattern. This indicated that the failure resistance of pure carbon fiber composites was improved after inserting basalt fiber layers.

The flow behaviors of TC18 titanium alloy are studied in the α+β regime by hot compression tests at the strain rates of 0.001–0.1 s−1 and temperatures of 1033–1123 K. The deformation characteristics of this alloy are greatly influenced by deformation conditions. The stress descends with the decreased strain rate or the increased temperature. The dynamic recrystallization behavior becomes weaken, while the dynamic recovery behavior tends to be more obvious with increasing deformation temperature. The deformation storage energy can effectively promote the transformation from α phase into β phase. Meanwhile, the β phases permeate into the lamellar α phases, resulting in the fragmentation and spheroidization of lamellar α phases. Three constitutive models, including the strain-compensated Arrhenius-type, Hensel-Spittel (HS) and artificial neural network (ANN) models, are constructed to depict the flow behaviors of the studied alloy. The correlation coefficients of the measured and predicted results are 0.9866, 0.9739 and 0.9971, respectively, for the constructed strain-compensated Arrhenius-type, HS and ANN models. Also, their average absolute relative errors are 6.51%, 8.30% and 1.68%, respectively. Therefore, three models can well describe the flow behavior of the studied alloy, and the prediction accuracy of ANN model is the best among three constitutive models.

The high-temperature flow characteristics and microstructural changes of alloys are usually investigated by isothermal compressive experiments at constant strain rates. However, during the practice industrial production of components, the strain rate is varying. In the present work, the microstructure changes and high-temperature flow characteristics of a Ni-based superalloy containing δ phases were researched by isothermal two-stage high-temperature compression experiments with stepped strain rates. It is revealed that the true stress of the later stage distinctly increases when the true strain/strain rate of the former stage or the strain rate of the later stage are raised. Meanwhile, the dynamic recrystallization (DRX) grains become finer, and the dissolution of δ phase is weakened. But, the coarsening of DRX grains and the dissolution of δ phase are enhanced as the deformation temperature is raised. The primary DRX nucleation mechanism is the discontinuous DRX. Based on the measured flow stress, an e-insensitive support vector regression (e-SVR) model is established for depicting the flow behavior of the researched alloy. The measured results are consistent with the forecasted ones, which illustrating that the developed e-SVR model is feasible to accurately describe the flow behaviors of the researched alloy during two-stage high-temperature deformation with stepped strain rates. Keywords: Hot deformation, Constitutive model, Microstructure, Dynamic recrystallization, Precipitates

A planar mixed-potential sensor was prepared based on SnO2 sensing electrode of hierarchical porous hollow nanofibers. The electrode was featured by three-dimensional scaffold architecture with high porosity, large pore size, and excellent pore interconnectivity. A response value of −289.1 mV and response time of 5 s were achieved at 450 °C for 1000 ppm H2, which were 5 and 2.6 times better than those of a similar sensor with sensing electrode of SnO2 nanoparticles, respectively. The response values exhibited a linear or logarithmic dependence on the H2 concentration for below or above 140 ppm, respectively, corresponding to a change from diffusion- to reaction-controlled kinetics. Power-law concentration dependence was observed for the response time, which also exhibited a similar transition at 140 ppm. Moreover, excellent selectivity, long-term stability, and repeatability were achieved. The morphology-dependent sensing behavior was discussed in terms of the diffusion-reaction process and Thiele modulus. These results highlight the importance of morphology to mixed-potential gas sensors, and show that hierarchical nanofiber electrode is desirable for achieving high gas sensing performance.

Generally, the hot deformation behaviors and microstructural evolution of alloys are studied by isothermal hot compressive experiments. However, in the practice industrial production, the temperature in metallic parts is variant in hot forming process. In this study, the deformation mechanism and microstructural evolution of a solid-solution Ni-Fe-Cr-base superalloy during the non-isothermal two-stage hot compressive deformation are investigated. Here, the deformation temperature of the first stage is 1040 °C, while those of the second stage are 950, 980, and 1010 °C. Meanwhile, the dynamic recrystallization (DRX) behaviors and nucleation mechanisms are analyzed. It is found that the temperature of the second stage (namely the final deformation temperature) has a great impact on the microstructures. During the non-isothermal two-stage hot deformation, the DRX volume fraction increases as the deformation degree of the first stage or the final deformation temperature is increased, or the strain rate is decreased. Compared with the isothermal hot deformation, DRX behaviors are more obvious during the non-isothermal two-stage hot deformation. In addition, DRX nucleation mechanisms mainly consist of discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) during the non-isothermal two-stage hot deformation. Furthermore, DDRX plays the primary role.

In this work, a plasmonic metallic Bi deposited BiPO4/BiWO6 heterostructure with surface oxygen vacancies was synthesized through one-step solvothermal method. The successful synthesis of material was confirmed by a series of characterization techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, UV–vis diffuse reflection spectroscopy, electron paramagnetic resonance, transmission electron microscope, photoluminescence spectroscopy. The characterization results showed that the surface oxygen vacancies were concentrated on the surface of BiPO4. The photocatalytic activity of Bi/BiPO4/Bi2WO6 was evaluated by photocatalytic decomposition of methylene blue and 2,4-Dichlorophenol under simulated sunlight irradiation. Meanwhile, with the addition of hydrogen peroxide, the photocatalytic efficiency would be further improved. The presence of rich surface oxygen vacancies and photo-induced electron were beneficial to produce hydroxyl radicals. The enhanced photocatalytic activity of Bi/BiPO4/Bi2WO6 heterostructure was ascribed to high separation efficiency of photo-generated electron–hole pairs, which aroused by the synergistic effects of heterojunction among different components, surface plasmonic resonance effect of Bi, and the surface oxygen vacancies.

Bi/α-Bi2O3 nanoparticles rich in oxygen vacancies in the surface and subsurface loading on g-C3N4 nanosheets were realized via a calcination-photoreduction technique, during which the emergence of oxygen vacancies and the generation of metallic Bi from α-Bi2O3 decomposition were achieved simultaneously. The co-occurrence of Bi nanoparticles and oxygen vacancies was favorable for the consumption and separation of the photogenerated electrons and holes. The three-component heterojunction photocatalyst (Bi/α-Bi2O3/g-C3N4, labeled as BBC) exhibited a remarkably high photocatalytic activity under the visible light irradiation, the degradation rate reached almost 90.2% for Tetracycline (TC) and 95.6% for RhB after 180 min and 90 min reaction respectively, far outperforming other decent photocatalysts under the same conditions. The enhanced photocatalytic activity was attributed to the synergistic effect of surface oxygen vacancies (OVs) and Bi nanoparticles. Furthermore, a probable photocatalytic mechanism for degrading the target contaminants by BBC photocatalysts was tentatively proposed.

In order to study the flow behaviors of an Al-Zn-Mg-Cu alloy at elevated temperatures, uniaxial tensile tests were carried out in wide deformation temperature and strain rate ranges. The flow stress rapidly increases to a peak value and then slightly decreases with the increased strain, and the dynamic recovery (DRV) is the primary softening mechanism. A unified constitutive model based on dislocation density was developed. An iterative procedure was implemented into the developed model to describe the flow behaviors at time-variant deformation conditions (e.g. the strain rate is changed during hot deformation). The predicted flow stresses were in accord with the experimental results, suggesting that the flow behaviors of the studied Al alloy at elevated temperatures can be well reproduced by the developed model. Meanwhile, the variations of the product of the instantaneous work hardening (WH) rate and stress caused by dislocation evolution, the dislocation density changing rate, as well as the dislocation mean free path, were given to analyze the WH and DRV mechanisms of Al-Zn-Mg-Cu alloy.

Aluminum sandwich panels with honeycomb core have been widely used as energy absorption structure in lightweight design. This study aimed to characterize the indentation and perforation behaviors of sandwich structures with different geometric configurations. The specimens with four characteristic geometric variables, namely, facesheet thickness, core height, honeycomb core thickness and side length of hexagon cell were tested experimentally. Photographs of cross-sectional view near the loading area and failure modes in the tests were investigated in detail. For the first time, digital image correlation (DIC) technique through an ARAMIS™ real-time optical strain measurement system was adopted for capturing the deformation process of lower skin by acquiring the displacement-time data. Three typical damage modes were identified from the force-displacement curves with different geometric parameters and configurations. It was found that the thickness of facesheet has the most significant effects on both force-displacement curves and energy absorption capacity. Changes in the core parameters have relatively small influences in total energy absorption but sizeable effects on the force-displacement curve and failure modes. A finite element model for predicting damage evolution was also developed and validated through the force-displacement relation and deformation process on the bottom skin. The damage mechanisms of the sandwich panel subject to quasi-static indentation and perforation were analyzed through the numerical models. The present study contributed on understanding how the geometric parameters affect the characteristics of indentation and perforation, thereby providing useful guidelines for its potential applications in impact engineering.

2–2 piezo-composite material (PCM) with high electromechanical coupling coefficient and low acoustic impedance is a kind of common PCMs for fabricating piezo-composite ultrasonic transducer (PCUT). The performance of PCUT is obviously influenced by the design parameters (DPs) of 2–2 PCM, such as its thickness, kerf, and slice width. Combining the finite element analysis simulation and artificial intelligence methods, an intelligent optimization design method is proposed to optimize the DPs of 2–2 PCM to fabricate high-performance 2–2 PCUT. In the proposed method, the neural network models are trained by the simulation data to build up the relationship between the DPs and the performance of PCUT. Using the optimization criteria established based on the center frequency (CF), bandwidth (BW), and peak-to-peak voltage (PV), the modified particle swarm optimization algorithm is employed to determine the DPs of 2–2 PCM. The desired CF, BW, and PV are 4 MHz, 40% and 3.2 V, and the optimized thickness, kerf and slice width of 2–2 PCM are 376 µm, 69.6 µm, and 34.4 µm, respectively. Finally, the optimized 2–2 PCUT is fabricated based on the optimized DPs, and then characterized systematically. The optimized 2–2 PCUT exhibits a CF of 4.57 MHz, a BW of 41.6%, a PV of 2.89 V, and an electromechanical coupling coefficient of 0.71. The simulation and experiment results are consistent with the designed targets, which verifies the availability of the proposed method.

A novel efficient Bi modified Bi 2 S 3 pillared g-C 3 N 4 (BBC) plasmonic semiconductor photocatalyst has been successfully developed in a mixed solvothermal environment. The photocatalytic abilities of the as-prepared samples are examined by the photocatalytic reduction of Cr(VI) and oxidation of tetracycline (TC). And the chemical composition, structure, morphology and photo-absorption properties of the photocatalysts have been investigated by XRD, FT-IR, XPS, TEM, HRTEM and DRS methods, respectively. It is found that the addition of triethanolamine (TEA) results in the formation of the pillared-g-C 3 N 4 (PG) nanostructure. The agglomeration of g-C 3 N 4 nanosheets moiety and Bi 2 S 3 nanorods moiety can be both hindered effectively by the special PG structure. And the photocatalytic results indicate that BBC exhibits the best photoreduction and photooxidation performances among all the samples, and meanwhile possesses superior photo-stability during the recycling runs. The enhanced photocatalytic activity of BBC could be ascribed to the furtherance of charge separation, localized surface plasma resonance (SPR) effect of metallic Bi and the excellent reaction interface. Finally, a tentative mechanism of BBC for photocatalytic reduction of Cr(VI) and oxidation of TC is discussed in detail.