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In this article, room temperature gallium-based fluids (RTGFs) with unique thermal and conductive properties are proposed as a transmission fluid for the force carrying medium of hydraulics, which rectify the lack of the multi-functional hydraulic roles of liquid metal (LM). The typical physical properties of RTGFs and comparative conventional hydraulic fluids (commercial hydraulic oil and deionized water), such as thermal stability and rheological characteristics are evaluated. Experimental and numerical methods, then, are adopted to clarify the force transmission performance of RTGFs and commercial hydraulic oils, as well as the influence of temperature fields on the viscosity of fluids. The results disclosed that the advantages of inherent flame resistance, wide liquid temperature range, and the viscosity changing slightly with temperature, make RTGFs potential to efficiently apply in the hydraulics as new working fluids. Finally, for illustration, the rigid and flexible actuators driven by RTGFs were designed as hydraulic fluid and demonstrated their capabilities in grasping objects with various shapes and weights, respectively. And the tunable stiffness of such a flexible actuator is enabled via the solid-liquid phase change of LM. Additionally, a frequency-adjustable antenna was manufactured and showcased owing to the introduced transformable electromagnetic behaviors of LM. Overall, the gallium-based LM fluids with thermoelectrical and mechanical multimodal signal medium, would serve as a potential candidate for future complex multifunctional signal transmission systems.

Considering the complexity geometry and thin wall feature, the semiconical shell workpiece will induce complicated and intense vibration in the milling process leading to poor surface quality and large machining deformation. In order to suppress the vibration, this paper focused on the semiconical shell workpiece and proposed a multiple distribution tuned mass damper (MDTMD) vibration control technique by attaching a series of optimized tuned mass dampers (TMD) to each optimal position of workpiece. The vibration characteristics and modal shapes of workpiece were obtained with the use of spectro-geometric-Ritz method (SGM) and the dynamic model of workpiece with MDTMD was established. A novel design of TMD was proposed. The optimal parameters and positions of each TMD were determined simultaneously using numerical optimization algorithm based on the modal summation method. Theoretical studies and experiment results shown that the proposed MDTMD method can remarkably improve the dynamic stiffness of the workpiece. The performance of vibration suppression is further verified in the impact tests and milling experiments.

Based on the first-principles calculations of density functional theory, co-adsorption models of C or CO with Cl2 on rutile TiO2 (100) surface were established. The adsorption structures and electronic properties during chlorination process were predicted. Then, the adsorption energy, charge density, electron density difference and density of state of the adsorption structures were calculated and analyzed. The stabilities of the adsorption structures and the charge distributions between atoms were studied. It was found that both C and CO could promote the adsorption reactions of Cl2 on TiO2 (100) surface, and C was more favorable to the adsorption process. The results show that the adsorption process of Cl2 on TiO2(100) surface was physisorption, and the co-adsorption processes of C or CO with Cl2 on TiO2(100) surface were chemisorptions.

The study of the adsorption mechanism of C and Cl2 on the TiO2 (110) surface is of great significance for the formulation of the technological parameters in the fluidized chlorination process. Based on the first-principles calculations of density functional theory, the co-adsorption models of C and Cl2 on the rutile TiO2 (110) surface under different ratios were established. The adsorption structure, adsorption energy, charge density, and density of states were calculated and analyzed to reveal the reaction mechanism of C and Cl2 adsorbed on the rutile TiO2 (110) surface under different ratios. The results showed that with the increase of the ratio of C atoms in the reaction process, the complete adsorption possibility of Cl atoms on the surface of TiO2 (110) increased. Both Ti6c and C atoms were electron providers, while O3c and O2c were electron acceptors. The bonding interactions between C and O2c or C and Cl atoms were stronger, and the stabilities were higher. When C bonded with O2c and two Cl atoms, respectively, the overlapping peak width of C and O2c atoms was greater at the high energy level, and the electron delocalization was enhanced, and more electrons were transferred around the two Cl atoms. When C bonded with O2c and one Cl atom, respectively, the electron activity at the low energy level was higher, and the stability of the chemical bond was lower.

To realize the functions of de-icing and self-propelling of droplet, one soft and superhydrophobic microfluidic chip (SMC) equipped with the liquid metal was successfully fabricated in this work. After modification via nanostructures and lower surface free energy cover, the SMC surface shows self-cleaning performance. The surface not only could realize self-propelling of droplet at room temperature but also uni-directional de-icing even −30 °C after melting. The results indicate the driving force is induced by the thermal gradient, which is generated by resistance heating of liquid metal (GaIn24.5). This study is significant for extending the applications of microfluidic chip in low temperature condition.

We herein present a case study on the templated, Pd-catalyzed polymerization reaction of methyl propiolate in the confined pore space of three different surface anchored metal–organic framework (SURMOF) systems in order to introduce electrical conductivity to MOF thin films and provide predictions for potential device integrations. To gain comprehensive insight into the influence of the template on polymerization, we chose Cu(bpdc), Cu$_{2}$(bdc)$_{2}$ (dabco) and HKUST-1 because of their different types of pore channels, 1D, quasi-1D and 3D, and their free pore volumes. Well-defined MOF thin films were prepared using layer-by-layer deposition, which allows for the application of several characterization techniques not applicable for conventional powder MOFs. With SEM, AFM, XRD, MALDI-ToF/MS, ToF-SIMS and QCM, we were able to investigate the behaviour of the polymer formation. For lower dimensional pore channels, we find a depot-like release of monomeric units leading to top-layer formation determined by desorption kinetics, whereas for the 3D channels, quick release of an excess amount of monomers was observed and polymerization proceeds perfectly. Despite polymerization issues, control over the maximum chain lengths and the molecular weight distribution was achieved depending on the dimensionality of the pore systems. For the HKUST-1 system, polymerization was optimized and we were able to measure the electrical conductivity introduced by the conjugated polymer inside the channels

A novel hybrid battery thermal management system, combining air-forced convection with phase change material, is proposed. The effectiveness of the system is proved experimentally. The maximum temperature difference and the maximum temperature are controlled within the optimum range in the proposed thermal management system even though the dynamic charge/discharge current rate is 4 C rate. Meanwhile, the thermal performance is also compared under the passive and active strategy. The result shows that the thermal performance under the active mode is obviously superior to that under the passive mode. Comparing with the passive mode, the maximum temperature difference and the maximum temperature in the active mode are reduced 1.2 °C and 16 °C under 3 C rate, respectively. Moreover, the mathematical model, based on the three-dimension heat transfer model coupled with the electrochemical model, is carried out and then validated with experimental data. Taking advantage of the mathematical model, the space of designed structures is further optimized.

Experiments show that high purity titanium (HP-Ti) samples have been successfully processed by equal channel angular pressing (ECAP) using a 120 degree die and a relatively slow ram speed at cryogenic temperature when the HP-Ti rods were trapped with 6061 Al alloy tubes. Optical microscopy (OM) and transmission electron microscopy (TEM) were utilized to investigate the deformed microstructure of the material. Typical microstructures of shear bands and deformation twinning were found in the deformed microstructure of ECAPed HP-Ti. Furthermore, the SAED pattern analysis of the twinning structures revealed that the deformation twinning occurred on {112} planes. Keywords: High purity titanium; ECAP; TEM; Deformation twinning; Cryogenic temperature.

A novel NASICON-type K0.24Na2.76Fe2(PO4)3 (K0.24NFP) is synthesized via a simple solid-state reaction method. K-doped method can enlarge lattice distance and restrain the structure dilapidation from Na3Fe2(PO4)3 to Na5Fe2(PO4)3. Comparison with undoped-Na3Fe2(PO4)3 (NFP) sample (82.1 mAh g−1), K0.24NFP electrode shows a 101.3 mAh g−1 discharge capacity at 10 mA g−1, which up to 97% of theoretical capacity. As for rate capability performance, a high reversible capacity of 73.6 mAh g−1 at 1000 mA g−1. The cycle stability performance measurement results indicate that the discharge capacity of K0.24NFP electrode is up to 93.7 mAh g−1 after 500 cycles at 100 mA g−1. The excellent electrochemical performance is attributed to the improvement of structural stability and the highest intercalation-deintercalation kinetic of sodium-ions (DNa+ = 3.98 × 10−11) due to K-doped. Hence, the K-doped iron-based phosphate (K0.24Na2.76Fe2(PO4)3) should be a potential cathode material in sodium-ions batteries for scale energy storage.

A new approach was developed for enhancing the thermoelectric performance of In2O3(ZnO)5 ceramics. Ni coating layer on the surface of In2O3(ZnO)5 powders was prepared by chemical plating. The Ni-Coated In2O3(ZnO)5 powders was densified to composite bulk with Ni enrichment in the grain boundaries. The composite sample obtained a remarkably enhanced dimensionless thermoelectric figure of merit (ZT) of 0.39 at 973 K, which is 3.6 times higher than that of a pristine In2O3(ZnO)5 sample.

The effect of the cooling water flow path on the flow and heat transfer in a double tube-pass condenser for a 660 MW power plant unit was numerically investigated based on a porous medium model. The results were used to analyze the streamline, velocity, air mass fraction and heat transfer coefficient distributions. The simulations indicate that the cooling water flow path is important in large condensers. For the original tube arrangement, the heat transfer with the lower-upper cooling water flow path is better than that with the upper-lower cooling water flow path. The reason is that the steam cannot flow into the internal of upper tube bundle and the air fractions are higher in the upper tube bundle with the upper-lower cooling water flow path. An improvement tube arrangement was developed for the upper-lower cooling water flow path which reduced the back pressure by 0.47 kPa compared to the original scheme. Thus, the results show that the tube arrangements should differ for different cooling water flow paths and the condenser heat transfer can be improved for the upper-lower cooling water flow path by modifying the tube arrangement.

This communication provides an integrated process route of smelting gallium-based liquid metal (GBLM) in a high vacuum, and injecting GBLM into the antenna channel in high-pressure protective gas, which avoids the oxidation of GBLM during smelting and filling. Then, a frequency-reconfigurable antenna, utilizing the thermal expansion characteristic of GBLM, is proposed. To drive GBLM into an air-proof space, the thermal expansion characteristics of GBLM are required. The dimensions of the radiating element of the liquid metal antenna can be adjusted at different temperatures, resulting in the reconfigurability of the operating frequency. To validate the proposed concept, an L-band antenna prototype was fabricated and measured. Experimental results demonstrate that the GBLM in the antenna was well filled, and the GBLM was not oxidized. Due to the GBLM being in an air-proof channel, the designed liquid metal antenna without electrolytes could be used in an air environment for a long time. The antenna is able to achieve an effective bandwidth of over 1.25–2.00 GHz between 25 °C and 100 °C. The maximum radiation efficiency and gain in the tunable range are 94% and 2.9 dBi, respectively. The designed antenna also provides a new approach to the fabrication of a temperature sensor that detects temperature in some situations that are challenging for conventional temperature sensing technology.

We demonstrate an efficient scheme to accelerate the self-similar pulse evolution and reduce the intensity noise of a free-running femtosecond fiber amplifier based on the pump wavelength optimization. Experiments and simulations indicate the enhanced tolerances of the pulse self-similar amplification to the seed signal power and pump wavelength fluctuations, with the optimum 915 nm pump wavelength. ∼20% increase in the compressed pulse quality and ∼31% reduction in the amplifier root-mean-square (RMS) relative intensity noise (RIN) (1.5 kHz to 5 MHz) have been observed, even with a more than 4 times higher pump laser diode (LD) RIN than the case of 976 nm. ∼50 fs transform-limited pulses are generated with the ∼0.03% amplifier RMS RIN. The proposed scheme can lower the requirements of low-noise self-similar femtosecond fiber amplifiers on the power stability of the seed oscillator and the thermal control of the pump LD, thus denoting potentials for the various satellite-based high-precision applications of femtosecond laser in space.

Advanced analytical applications require smart materials and sensor systems that are able to adapt or be configured to specific tasks. Based on reversible photochemistry in nanoporous materials, we present a sensor array with a selectivity that is reversibly controlled by light irradiation. The active material of the sensor array, or electronic nose (e-nose), is based on metal–organic frameworks (MOFs) with photoresponsive fluorinated azobenzene groups that can be optically switched between their trans and cis state. By irradiation with light of different wavelengths, the trans–cis ratio can be modulated. Here we use four trans–cis values as defined states and employ a four-channel quartz-crystal microbalance for gravimetrically monitoring the molecular uptake by the MOF films. We apply the photoprogrammable e-nose to the sensing of different volatile organic compounds (VOCs) and analyze the sensor array data with simple machine-learning algorithms. When the sensor array is in a state with all sensors either in the same trans- or cis-rich state, cross-sensitivity between the analytes occurs and the classification accuracy is not ideal. Remarkably, the VOC molecules between which the sensor array shows cross-sensitivity vary by switching the entire sensor array from trans to cis. By selectively programming the e-nose with light of different colors, each sensor exhibits a different isomer ratio and thus a different VOC affinity, based on the polarity difference between the trans- and cis-azobenzenes. In such photoprogrammed state, the cross-sensitivity is reduced and the selectivity is enhanced, so that the e-nose can perfectly identify the tested VOCs. This work demonstrates for the first time the potential of photoswitchable and thus optically configurable materials as active sensing material in an e-nose for intelligent molecular sensing. The concept is not limited to QCM-based azobenzene-MOF sensors and can also be applied to diverse sensing materials and photoswitches., A sensor array with four identical photoresponsive azobenzene-containing metal–organic framework films is selectively irradiated. By photoprogamming the array, the sensor selectivity is switched and optimized.

Metallic glasses (MGs) with superior catalytic performance have recently been recognized as attractive candidates for wastewater treatment. However, further improving their performance will require knowledge of how to precisely regulate their electronic structures via compositional control. Here, two Fe-based MGs (Fe

Ultrasound-driven microbubbles can improve the sensitivity of imaging or promote macromolecules delivery. However, microbubble collapse during inertial cavitation (IC) is followed by the creation of smaller daughter bubbles, that could grow and be nuclei for acoustic cavitation. Daughter bubbles exposure to ultrasound may cause undesired bioeffects in targeted region, thus it is important to determine the properties of daughter bubbles generated by IC to achieve controllable cavitation dose during therapy. In this study, theoretical dissolution dynamics of sulfur hexafluoride bubbles was calculated firstly. Then, we applied a 1-MHz single pulse with different peak negative pressures (PNPs) and pulse lengths (PLs), and multiple 5-MHz pulses with fixed acoustic conditions to elicit IC of the preformed SonoVue microbubbles and scattering of daughter bubbles, respectively. After the IC and scattering signals were received by a 7.5-MHz transducer, time- and frequency-domain analysis was performed to obtain the IC dose and scattering intensity curve. The theoretical dissolution curves and measured scattering intensity curves were combined to determine the effect of the incident pulse parameters on the lifetime, mean radius and distribution range of daughter bubbles. Increasing the PNP reduced the lifetime and mean size of the daughter bubbles population and narrowed the size distribution. The proportion of small daughter bubbles (less than resonance size) increased with an increase in the PNP from 0.6 to 1.6 MPa. Moreover, increasing the PL caused a shift of the daughter bubbles population to the smaller bubbles with shorter lifetime and narrower distribution. The proportion of small bubbles increased from as the PL was increased from 5 to $\mathbf{100}\ \mu \mathbf{s}$ . Finally, increasing the IC dose caused a smaller mean size, shorter lifetime and narrower distribution in the daughter bubbles population. These results provide new insight into the relationship between the incident acoustic parameters and the properties of daughter bubbles.

The organic-inorganic lead halide perovskites are attractive materials for photovoltaic application. The most widely studied perovskites based on methyl ammonium organic cation are less likely to form an ideal high-symmetry configuration at room temperature, leading to the appearance of local lattice strain. Herein, this study reports a strategy for the construction of thermally stable cubic perovskites at room temperature through the incorporation of the larger organic cation dimethyl ammonium. Detailed characterization on the single crystals and thin films reveals the formation of cubic phase with the addition of a certain amount of dimethyl ammonium at room temperature. With the presence of dimethyl ammonium, the nonradiative recombination in perovskite is suppressed, showing a longer PL lifetime and hole diffusion length. The more efficient charge extraction leads to an improvement in the photocurrent density, and then the device efficiency from 17.1% to 18.6%, together with an enhanced thermal stability at 85 °C. The influence of incorporating a larger organic cation on the structural configuration, optical properties, charge extraction, as well as the photovoltaic performance is systematically investigated, which offers an alternative way to improve the intrinsic stability of hybrid perovskites.

Distinct corrosion behavior was reported in multiphased titanium alloys prepared by additive manufacturing and by traditional technologies because of different phase constituents formed during processing. An open question is therefore raised: is there always different corrosion behavior of materials prepared by different methods? This work reports resemble corrosion behavior of selective laser melted and wrought single β-phase Ti-24Nb-4Zr-8Sn (Ti2448) in both NaCl solution and Hank's solution. The electrochemical measurements showed that both samples have close calculated polarization resistance and corrosion potential in NaCl solution, i.e., 4.99 ± 0.63 MΩ cm2 and -0.26 ± 0.01 V for the selective laser-melted Ti2448, and 4.42 ± 0.71 MΩ cm2 and -0.25 ± 0.01 V for the wrought Ti2448, respectively. Both samples reveal the same variation in weight change after 180-day immersion test in Hank's solution. Such resemblance in corrosion behavior without pitting morphologies is attributed to the formation of monolithic β-phase during processing, which demonstrates that titanium alloys with single phase show comparable corrosion behavior regardless of the manufacturing methods adopted.

Digenite (Cu1.8S) has attracted extensive attention as candidate for use in thermoelectric applications due to its low-cost, low-toxicity characteristics, but the thermoelectric (TE) property is still not good. In this work, PbS was used for improving TE properties of polycrystalline Cu1.8S bulk. Cu1.8S+ x wt% PbS (x = 0, 0.5, 1, 2, 3) bulk samples were fabricated via mechanical alloying (MA) and spark plasma sintering (SPS) techniques. The effects of adding PbS on the TE performance of Cu1.8S were investigated in detail at the temperature between 323 K and 773 K. According to the results, introducing PbS is an efficient approach for optimizing the TE properties of Cu1.8S, which is mainly due to the maintained electrical transport properties by the regulated hole carrier concentration and the modified band structure, as well as the reduced the thermal conductivity by the generated point defect and additional interfaces. An optimum thermoelectric figure of merit (ZT) value of 1.1 was obtained at 773 K for the Cu1.8S sample with 2 wt% PbS, which is 2.2 times higher than that of the pristine Cu1.8S (0.49 at 773 K).

This paper proposes a general finite element method (FEM)-based wavenumber domain analysis (WDA) to calculate scattering characteristics of surface acoustic wave (SAW) on arbitrary piezoelectric substrates. We add a damping loss mechanism (DLM) to the SAW injection port to avoid interferences from the incident and backscattered modes. After checking the validity of the proposed method, we calculate and study Sezawa mode scattering using a small number of electrodes on the ScAlN/3CSiC structure for demonstration. The frequency dependences of reflection and transmission coefficients and that of the power dissipation ratio for different termination conditions and electrode thicknesses are calculated. Also, the influence of base substrate materials and that of gratings on scattering parameters are explored. Investigation results demonstrate that high reflectivity with suppressed mode conversion can be obtained for the ScAlN-based layer structure if a base substrate with an extremely large velocity is used and if proper grating design is applied.

A Ti-5Cu alloy produced by selective laser melting exhibits a nonuniform Ti2Cu phase structure, which contains a small amount of α′ phase in melt pool boundaries thereby resulting in reduced corrosion resistance. The heat-treatment process proposed in this work eliminates the deleterious effect of α′ phase and the Ti2Cu phase is refined using different cooling rates, which improves the corrosion resistance. The electrochemical results indicate that the heat-treated Ti-5Cu samples have similar corrosion behavior to pure CP-Ti. A slower cooling rate produces a larger spacing between the Ti2Cu phases in the microstructure of the sample, resulting in higher corrosion resistance. The corrosion behavior of SLM-produced Ti-5Cu and heat-treated counterparts with different microstructure are detailed discussed.

The electrical conductivity, Seebeck coefficient and thermal conductivity of the Cu1−xIn1−ySe2.05 alloys were investigated, which were synthesized by solid-state reaction method combined with spark plasma sintering (SPS) technique. With the increasing of vacancy contents, the electron and phonon scattering were enhanced. The electrical and thermal transport properties of the samples changed accordingly. The Cu0.99InSe2.05 bulk sample achieves the highest ZT value of 0.31 at 773 K due to optimized electrical and thermal transport properties, which is 3 times higher than that of pristine CuInSe2.05. Moreover, it is the highest ZT value in CuInSe2 system in all of previous literatures.

We report the use of 2H-NbS2 film as a novel counter electrode in perovskite solar cells fabricated with a cold isostatic pressing method. The 2H-NbS2 film, which was prepared through an exfoliation method followed by restacking from LixNbS2 powder, shows high electrical conductivity of 8.7 × 103 S cm−1 and work function of 5.20 eV. The two-dimensional transition metal dichalcogenide was used for the first time as a counter electrode in meso-structured perovskite solar cells. Through this process, we demonstrated a new alternative to noble metals. The perovskite solar cell base on the 2H-NbS2 counter electrode showed an open-circuit voltage of 1.046 V, comparable to that of gold, and a power conversion efficiency of 8.3%.

Although the parts produced by selective laser melting (SLM) are reported to possess comparable or better mechanical properties than the traditionally processed counterparts, the SLM-produced parts demonstrate slightly unfavorable corrosion resistance properties compared with their traditional counterparts. This work shows that, in addition to rapid manufacturing of parts, SLM can effectively refine the grains of eutectic Al-12Si alloy. The SLM-produced Al-12Si shows an ultrafine-grained microstructure and improved corrosion resistance, which provides an innovative and efficient approach to refine the silicon particles in eutectic Al-12Si alloy. Unlike the microstructured Al-12Si alloy manufactured by traditional casting, the SLM-produced Al-12Si alloy contains ultrafine-grained eutectic silicon particles distributing in the aluminum substrate. Importantly, it is found that the SLM-produced Al-12Si alloy possesses superior corrosion resistance than the cast Al-12Si alloy in terms of the results from electrochemical methods and weight loss test. The favorable corrosion resistance of SLM-produced Al-12Si is attributed to these ultrafine silicon particles, which prominently benefits for the formation of the oxide film. The influence of the microstructure with regard to eutectic silicon particles size on the corrosion resistance has also been discussed in depth. Keywords: Selective laser melting, Corrosion resistance, Eutectic Al-12Si alloy, Ultrafine microstructure

Electrochemical measurements and microstructural studies were carried out to investigate the corrosion behaviour of the different planes for the Al-12Si alloy produced by selective laser melting (SLM). The electrochemical results demonstrate that the building direction plane (XZ-plane) of the SLM-produced alloy exhibits better corrosion resistance in comparison with the building plane (XY-plane) in 3.5 wt% NaCl solution. The relatively inferior corrosion resistance of the XY-plane is ascribed to that the grown corrosion products extrude the deep and small-bore Si shells on the aluminum substrate, thereby causing the crack of Si shells. Without such a cover of the Si shells, the Cl− would continuously penetrate into the aluminum substrate and ultimately induce occurrence of the severe pitting. As for the XZ-plane, the corrosion products cannot grow and deposit in its shallow and large-bore Si shells, instead of transferring to the testing solution. The undamaged Si shells and formed oxide film constitute a protective layer to protect the aluminum substrate from the attack of Cl−, thereby displaying superior corrosion behaviour for the XZ-plane.

Extensively investigated BiVO4 photoanode for solar water splitting suffers from low product of light absorption and charge separation efficiency (ηabs × ηsep) due to the lack of high surface area supporting materials as a charge collector. Such a host|guest heterostructure is not only effective but also attractive, but it is too complicated to understand the original process of ηsep. Here, a host–guest heterostructure of Nb-doped TiO2 nanowires supporting BiVO4 nanoparticles is fabricated to investigate its visible-light charge injection efficiency (ηinj) and charge collection efficiency (ηcol). With the aid of gradient W doping in BiVO4 guest, the Nb-doped TiO2|gradient W-doped BiVO4 (N:T|g-W:B) produces ηinj = 82% and ηcol = 95% to yield a very high value for ηabs × ηsep of 55.3% at 0.6 VRHE, which is one of the highest values among these nanostructure-host|BiVO4-geust photoanodes. By being further coated with Co–Pi, the photoanode simultaneously achieves a high value of ηtrans for efficient solar wate...

Discovering functional applications of metallic glasses (MGs) as heterogeneous catalysts is a fundamental and essential topic. This work reports the rapid production of sulfate radicals (SO4·−) from peroxymonosulfate (PMS) using Fe73.5Si13.5B9Cu1Nb3 glassy ribbons as catalysts for Eosin Y (EY) dye wastewater treatment. The reaction rates (k) from the experimental data reveal that the EY degradation is well fitted with the pseudo-first-order kinetic model. The strong electron transfer ability is characterized by electrochemical methods, presenting an advanced catalytic performance for EY degradation. Various experimental parameters, including dye concentration, catalyst dosage, PMS concentration, light intensity, pH and reaction temperature as well as the saline and natural inorganic effects, are fully investigated. The results show that the color removal of EY dye could achieve nearly 100% within 20 min. The quenching experiments are performed to verify the production of reactive species, suggesting that both ·OH and SO4·− are produced from PMS and play significant roles in EY degradation. This critical study reveals that using Fe73.5Si13.5B9Cu1Nb3 MGs as catalysts exhibits a superior reactivity on PMS activation in wastewater treatment. The discoveries shed lights into the study of electron transfer ability for MGs, presenting extensive prospects in the application of dye wastewater treatment. Keywords: Metallic glass, Heterogeneous catalysis, Peroxymonosulfate, Sulfate radicals, Eosin Y

The development of new strategies for the construction of highly selective and stable vapochromic system is still in great demand. Here, we present a highly selective and stable vapochromic system constructed by pillar[5]arene-based host–guest interactions between a pillar[5]arene (EtP5) and a phenazine derivative. The present material in this work showed specific selective responsiveness to chloroform vapor. The resultant dark orange solid sample was highly stable, which can maintain the color in air for at least two months at room temperature. Moreover, CHCl3 vapor responsive thin film and light-emitting diode (LED) was successfully prepared by coating the EtP5⊃1 complex on a glass sheet and a commercially available UV-LED. This work provided a new approach for the design and construction of selective and stable vapochromic systems with obvious color changes using pillar[5]arene-based host–guest interactions.

Amongst the background of the popularization of the lithium-ion battery (LIB), the thermal issues have attracted a significant amount of attention. In the present paper, a novel integrated system is proposed with thermal management and rapid cooling based on C6F12O spray cooling in a closed loop. Through experiments using a 4 × 4 dummy 18650 cylindrical battery pack, the cooling performance of the battery thermal management system (BTMS) based on the C6F12O spray cooling is demonstrated to be effective. Further, the controllable heat generation benefits for the analysis of heat dissipation mechanisms. For the condition of 6 cm spray height with 2.05 g/s flow rate, the heat is taken away by the liquid film accounted for around 30% of the total heat dissipation, while that of direct spray cooling accounted for around 70%. In the rapid cooling experiment, compared with the blank experiment, the thermal runaway maximum temperature significantly decreased by 517.1 °C and the thermal runaway of the first battery is delayed by 229 s. Owing to the significantly effective heat removal ability of C6F12O spray cooling, the propagation of the thermal runaway is cut off.

The temperature-dependent evolution of heavy-hole valence band contribution to the Seebeck coefficients of SnTe-based thermoelectric materials is revealed in situ by neutron and synchrotron powder diffraction. The additional carriers with high effective mass are created in a heavy-hole valence band above 493 K, which contribute to the electrical transport, and lead to a significant enhancement of the Seebeck coefficient at high temperature. In addition, remarkably improved electrical transport properties are achieved through the synergetic effects of the resonance levels, the valence band convergence, and the carrier concentration optimization by co-doping with Mg & In, Ag & In and Bi & In. Significant reduction in the lattice thermal conductivity is obtained by multiscale phonon scattering over a wide spectrum via atomic point defects, nanoscale elongated screw dislocations with random directions, and the microscale grain boundaries caused by sintering. As a result, a high figure of merit, ZT, of ∼1 at 873 K is obtained for the Mg0.015In0.015Sn0.97Te sample.

In this work, the corrosion and passivation behavior of Ti-6Al-4V produced by laser powder bed fusion (L-PBF) were investigated in different concentration of NaCl solutions under static and dynamic conditions. Oxide films including TiO2, Ti2O3, TiO were formed on L-PBF-produced Ti-6Al-4V. The film thickness increased under both test conditions with increasing the Cl− concentration, and the film contained more TiO2 in dynamic conditions under the same Cl− concentration. The mechanism of the corrosion behavior and film growth under different Cl− concentration and electrolyte conditions were discussed by the relevant electrochemical and surface characteristic measurements, e.g. Mott-Schottky analysis, X-ray photoelectron spectroscopy.

This work investigated the corrosion behavior and mechanism of selective laser melted (SLM) Ti35Nb separately using mixed powder (Ti35Nb-M) and pre-alloyed powder (Ti35Nb-P) in Hank’s solution. Both types of samples demonstrate similar corrosion behavior, and double-layered oxide films form on the TiNb regions in both Ti35Nb-M and Ti35Nb-P. However, Ti35Nb-P has more stable oxide films than Ti35Nb-M because the outer porous oxide layer formed on Ti35Nb-P has smaller thickness and less defects according to Mott-Schottky analysis. Distinct oxide films also form on the TiNb and Nb regions in Ti35Nb-M due to unmelted Nb particles.

Thermal management is crucial for the lifespan and safety of lithium-ion batteries, especially for the electrochemical energy storage which is composed of thousands of battery cells. In this paper, a novel battery thermal management system (BTMS) with internal finned structure was first proposed based on forced-air convection for the cylindrical battery pack in the field of electrochemical energy storage. The proposed battery thermal management system combined the advantages of forced-air convection and internal finned structure, capable of well managing the maximum temperature and the maximum temperature of the cylindrical battery pack. The experimental results of this study revealed that the internal finned structure improved the temperature uniformity and forced-air convection reduced the maximum temperature. Even though the battery pack operated under the 4 C rate, the maximum temperature and the maximum temperature difference are well controlled below 48.5 ℃ and 4.8 ℃. Moreover, a mathematical model was established. After its results were validated by experiments, it was used to analyze the effect of the gap space, ambient temperature, and finned material on the cooling performance. The numerical findings provided insights into the application of the proposed battery thermal management system. In practice, the gap space of aluminum finned structure should be set as 4 mm, and the cycling rate should be no more than 3 C at ambient temperature over 25 °C.

This work sheds light on the relationship between the quantities of synthesized core shell Gd 2 O 3 added to epoxy matrix and the mechanical and X-ray attenuation properties of particulate epoxy composite. Then, an optimal geometric design of non-lead based X-ray protective material with light weight per volume unit is prepared. A plateau with 28–30% increments in the value of fracture toughness (K IC ) is observed with a specific addition of 0.08–0.1 volume fraction ( φ S ) of Gd 2 O 3 particles in pure epoxy. The same quantity of particles also optimally raises the critical strain energy release rate and Young’s modulus of epoxy by approximately 22–24% and 18–25% respectively. A 16 mm thick sheet of fabricated filled composite at ( φ S ) of 0.08 and 0.1 can shield greater than 95% and 99% respectively of a primary X-ray beam in the range of 60–120 kVp. At the same X-ray attenuation (99% attenuation), the specimen is 7, 8.5 and 16 times lighter than wood, glass, and concrete, respectively. At 0.5 mm Pb-equivalence, the composite also has 4.5–19.4% less weight per unit area than current commercial non-lead products.

Cu-Se compounds have attracted more attentions as a low-cost, low toxicity thermoelectric materials. In this work, p-type Cu 2 Se x compound powders were prepared by solution syntheses, including the wet chemistry method and hydrothermal synthesis method. The reaction mechanisms were investigated, showing that the NaOH contents affected the phase structure of the final product. Polycrystalline Cu 2 Se x bulk materials were obtained by densifying the powders using spark plasma sintering (SPS) and obtained the maximum ZT value of 0.75 at 623 K, which is currently the highest reported value for the Cu-Se system at this temperature. We also found that the introduced oxides could suppress the long-range migration of Cu ions in Cu-Se system to avoid the decomposition of the materials.

The Cu–S compounds have been reported as promising thermoelectric materials with abundant element composition, low price, and low toxicity. In this work, SnxCu1.8−xS samples with different Sn contents (x = 0.005, 0.01, 0.03, and 0.05) were fabricated by mechanical alloying combined with spark plasma sintering. The phase structure and microstructure of all the bulk samples were checked by X-ray diffraction (XRD) and field emission scanning electron microscopy respectively. The thermoelectric transport properties, such as electrical conductivity, Seebeck coefficient, carrier concentration, carrier mobility, and thermal conductivity, were measured. The effect of second phase introduced by Sn addition on the thermoelectric properties of Cu–S system was investigated. The thermoelectric properties of samples were improved by the precipitations of two different second phases (Cu2SnS3 and Cu4SnS4). The second phase species depend on the Sn contents. Finally, the Sn0.01Cu1.79S bulk sample obtained the highest ZT value of 0.81 at 773 K, which is 1.6-fold higher than that of the pristine Cu1.8S sample due to the significantly reduced thermal conductivity by second phase and nanopores scattering.

The corrosion behaviour of CP-Ti and Ti-TiB composite produced by selective laser melting (SLM) in the artificial simulated body fluid (Hank's solution) at body temperature was investigated systematically by using electrochemical measurements (potentiodynamic polarisation curves and electrochemical impedance spectroscopy), together with some detailed structural characterisations. The results demonstrate that SLM-produced Ti-TiB composite samples possess better corrosion resistance than SLM-produced CP-Ti samples in Hank's solution. Due to these tiny TiB and TiB2 particles acting as the micro-cathode uniformly distributing in titanium matrix, anodic dissolution of titanium matrix in the corrosion process is prominently facilitated in early stages, followed by rapid passivation on the surface. The corrosion mechanism of Ti-TiB composite samples has also been discussed in detail in this paper.

SonoVue microbubbles could serve as artificial nuclei for ultrasound-triggered stable and inertial cavitation, resulting in beneficial biological effects for future therapeutic applications. To optimize and control the use of the cavitation of SonoVue bubbles in therapy while ensuring safety, it is important to comprehensively understand the relationship between the acoustic parameters and the cavitation behavior of the SonoVue bubbles. An agarose-gel tissue phantom was fabricated to hold the SonoVue bubble suspension. 1-MHz transmitting transducer calibrated by a hydrophone was used to trigger the cavitation of SonoVue bubbles under different ultrasonic parameters (i.e., peak rarefactional pressure (PRP), pulse repetition frequency (PRF), and pulse duration (PD)). Another 7.5-MHz focused transducer was employed to passively receive acoustic signals from the exposed bubbles. The ultraharmonics and broadband intensities in the acoustic emission spectra were measured to quantify the extent of stable and inertial cavitation of SonoVue bubbles, respectively. We found that the onset of both stable and inertial cavitation exhibited a strong dependence on the PRP and PD and a relatively weak dependence on the PRF. Approximate 0.25MPa PRP with more than 20μs PD was considered to be necessary for ultraharmonics emission of SonoVue bubbles, and obvious broadband signals started to appear when the PRP exceeded 0.40MPa. Moreover, the doses of stable and inertial cavitation varied with the PRP. The stable cavitation dose initially increased with increasing PRP, and then decreased rapidly after 0.5MPa. By contrast, the inertial cavitation dose continuously increased with increasing PRP. Finally, the doses of both stable and inertial cavitation were positively correlated with PRF and PD. These results could provide instructive information for optimizing future therapeutic applications of SonoVue bubbles.

Thermoelectric materials are a relatively new functional material that can be used for the direct conversion of thermal energy to electrical energy through the transmission and interaction of carriers and phonons in the solid. Polycrystalline p-type Cu1.8S dispersed with x wt% SiC nanoparticle (x = 0.1, 0.5, 1.0, 3.0) thermoelectric materials were fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The effects of the SiC nanoparticles on the thermoelectric properties of the material were investigated. The phase structure and microstructure of all the bulk samples were checked by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. Compared to pristine Cu1.8S, Cu1.8S polycrystals dispersed with nano-SiC showed increased Seebeck coefficients, decreased electrical conductivities, and reduced thermal conductivities in the temperature range of 323–773 K. The maximum dimensionless figure of merit (ZT) was improved from 0.49 for pristine Cu1.8S samples to 0.87 for the 1.0 wt% SiC dispersed Cu1.8S sample at 773 K.

The optimization of thermoelectric materials involves the decoupling of the transport of electrons and phonons. In this work, an increased Mg 1 -Mg 2 distance, together with the carrier conduction network protection, has been shown as an effective strategy to increase the weighted mobility ( U = μ m ∗ 3 / 2 ) and hence thermoelectric power factor of Mg 3+ δ Sb 2- y Bi y family near room temperature. Mg 3+ δ Sb 0.5 Bi 1.5 has a high carrier mobility of 247 cm 2 V -1 s -1 and a record power factor of 3470 μ W m -1 K -2 at room temperature. Considering both efficiency and power density, Mg 3+ δ Sb 1.0 Bi 1.0 with a high average ZT of 1.13 and an average power factor of 3184 μ W m -1 K -2 in the temperature range of 50-250°C would be a strong candidate to replace the conventional n-type thermoelectric material Bi 2 Te 2.7 Se 0.3 . The protection of the transport channel through Mg sublattice means alloying on Sb sublattice has little effect on electron while it significantly reduces phonon thermal conductivity, providing us an approach to decouple electron and phonon transport for better thermoelectric materials.

The objective of this work is to design an optimal controller to modulate the stable cavitation activity of microbubbles induced by pulsed ultrasound. During therapy, the microbubbles inflow the target region in the blood vessel, receive ultrasound exposure and produce cavitation activities, and then outflow the therapy region. The stability of the bubbles could be affected by acoustic pulses and flowing environment, leading to the decrease of bubble number and the nonuniformly temporal distribution of stable cavitation activity in the target region. Previous researches regulated peak negative pressure (PNP) to effectively control stable cavitation activity whereas some undesirable consequences (e.g. hemorrhage) were found after applying PNP regulation. We proposed a novel proportional feedback controller based on both PNP and pulse length (PL) regulation. In order to rapidly elevate stable cavitation intensity from baseline to the pre-expected level, in our controller, a proportional factor of P 1 was firstly used to real-time adjust PNP from the initial 0.01 MPa to an appropriate level of experiential stable cavitation range. The obtained PNP was fixed in the subsequent regulation, and another factor of P 2 was used to modulate PL from the initial 20 μs to the obtained expected intensity and minimize the overshoot of the stable cavitation intensity. P 3 was then applied to keep the temporal stability of stable cavitation activity (±10% fluctuation range of the expected cavitation intensity) by further modulating PL. Finally, three parameters (rising time, stability ratio and concentration ratio) were used to evaluate the performance of the proposed method. Experimental results validated that the proposed method could control temporal distribution of stable cavitation intensity in the target region.

Wireless passive surface acoustic wave (SAW) resonator has great potential in high temperature sensing applications. Nevertheless, degradation of metal electrodes and decrease of Q factors with rising temperature restrict the temperature upper limit of SAW resonators. From a structural perspective, a SAW resonator structure with grooved electrodes for interdigital transducers and groove-only grating for reflectors is proposed to improve the resonator performance at high temperatures. Quasi-3D periodic FEM models of platinum /trapezoidal-groove/langasite(0°, 22°, 30°) are established and the simulation results show that the grooved electrode is beneficial for electroacoustic coupling factor and pressure sensitivity. In addition, the groove-only grating with no metal reduces the negative effect of high temperature on resonator performance. It has been also verified by coupling-of-model theory that the spurious modes caused by structural difference can be suppressed.

A one-step strategy for fabricating flexible conductors via phase separation is proposed, wherein, the liquid metal was implanted into polydimethylsiloxane, whose viscosity was changed using hexane. Such self-encapsulating composite exhibited good electronic and mechanical stability under mechanical cycles with no significant leaking of droplets during the testing process.

Aqueous zinc-ion batteries (ZIBs) possess energy storages advantages, including low cost, high safety, and durable lifetimes. Materials are worth exploring to achieve high-performance batteries. Although Bi

The popularization of electric vehicles is no longer a speculation thanks to the advancement of the lithium-ion battery. However, safety issues prevent a larger-scale application of lithium-ion batteries. In energy storage industry, thermal runaway is the direct cause of fire and explosions. The thermal runaway numerical model attempts to unveil the mechanism of thermal runaway triggered by local overheating in this work, which is distinct from accelerating rate calorimeter tests or oven tests. The model is based on the energy conservation equation, and the source term of which is modeled by the empirical Arrhenius equations. Further on, the results of the numerical model are validated by experiments. Based on the calculated analysis on the heat contribution to the thermal runaway, the heat contribution of anode-electrolyte reaction is up to 63.8% of the total heat, and internal short circuit is responsible for a little proportion of total heat generation during thermal runaway which is contrary to the general thoughts, yet still a crucial inducement of chain reactions. The results also confirm the conclusion that enhancement of heat dissipation condition of battery can retard thermal runaway progress and reduce the maximum thermal runaway temperature. In addition, interior dynamic temperature distribution of the battery can be achieved, and characteristics of local overheating are compared with those of oven tests, noteworthy temperature difference in local overheating occasion is highlighted.

Highlights • DBs properties from theoretical dissolution curves and measured scattering intensity curves. • Increasing PNP reduced the mean size and lifetime of DBs, and narrowed size range. • Increasing PL caused a decrease in mean size, lifetime and size range of DBs. • IC dose negatively correlated with mean size, lifetime and size range of DBs., Inertial cavitation (IC) of the preformed microbubbles is being investigated for ultrasound imaging and therapeutic applications. However, microbubbles rupture during IC, creating smaller daughter bubbles (DBs), which may cause undesired bioeffects in the target region. Thus, it is important to determine the properties of DBs to achieve controllable cavitation activity for applications. In this study, we theoretically calculated the dissolution dynamics of sulfur hexafluoride bubbles. Then, we applied a 1-MHz single tone burst with different peak negative pressures (PNPs) and pulse lengths (PLs), and multiple 5-MHz tone bursts with fixed acoustic conditions to elicit IC of the preformed SonoVue microbubbles and scattering of DBs, respectively. After the IC and scattering signals were received by a 7.5-MHz transducer, time- and frequency-domain analysis was performed to obtain the IC dose and scattering intensity curve. The theoretical dissolution curves and measured scattering intensity curves were combined to determine the effect of the incident pulse parameters on the lifetime, mean radius and distribution range of DBs. Increased PNP reduced the lifetime and mean size of the DBs population and narrowed the size distribution. The proportion of small DBs (less than resonance size) increased from 36.83% to 85.98% with an increase in the PNP from 0.6 to 1.6 MPa. Moreover, increased PL caused a shift of the DB population to the smaller bubbles with shorter lifetime and narrower distribution. The proportion of small bubbles increased from 25.74% to 95.08% as the PL was increased from 5 to 100 µs. Finally, increased IC dose caused a smaller mean size, shorter lifetime and narrower distribution in the DB population. These results provide new insight into the relationship between the incident acoustic parameters and the properties of DBs, and a feasible strategy for achieving controllable cavitation activity in applications.

Along with the popularization of the lithium-ion battery (LIB), much more attention is attracted to its problem of thermal runaway. This paper proposes a simple but novel method to investigate the gas generation throughout the process of thermal runaway. The novelty from the previous study lies in that the battery cells without the cap are used as the test samples. The naked battery offers a key to decouple the pressure caused by the vapor of electrolyte and that of the gases generated in the chemical reaction. This study makes up the knowledge gap of measuring internal pressure before the venting behavior and provides a more accurate method to describe the gas generation of thermal runaway. Three 100% state of charge LIBs with the cathode of LiNi0·8Co0·1Mn0·1O2 are used as tested samples to illustrate the application of this method. Two important results are withdrawn from the samples’ test: (I) the relationship between temperature increasing rate and gas generation rate is not linear until battery temperature approaches the uncontrollable temperature; (II) the partial pressure of gas generated due to the redox reactions bears the major responsibility for the safety valve opening.

Bismuth sulfide (Bi2S3) has been of high interest for thermoelectric applications due to the high abundance of sulfur on Earth. However, the low electrical conductivity of pristine Bi2S3 results in a low figure of merit (ZT). In this work, Bi2S3@Bi core–shell nanowires with different Bi shell thicknesses were prepared by a hydrothermal method. The core–shell nanowires were densified to Bi/Bi2S3 nanocomposite by spark plasma sintering (SPS), and the structure of the nanowire was maintained as the nanocomposite due to rapid SPS processing and low sintering temperature. The thermoelectric properties of bulk samples were investigated. The electrical conductivity of a bulk sample after sintering at 673 K for 5 min using Bi2S3@Bi nanowire powders prepared by treating Bi2S3 nanowires in a hydrazine solution for 3 h is 3 orders of magnitude greater than that of a pristine Bi2S3 sample. The nanocomposite possessed the highest ZT value of 0.36 at 623 K. This represents a new strategy for densifying core–shell powde...

Thermoelectric (TE) materials have a promising application as they can interconvert thermal energy to electrical energy directly. Oxide TE materials have attracted more attention for this application due to their high temperature stability. In this work, In2O3(ZnO)5 intrinsic superlattice ceramics with a layered structure were synthesized by reaction sintering a mixed powder of In2O3 and ZnO at 1200 °C for different holding times (t = 6, 8, 10, 12 and 15 h) in air. Their thermoelectric properties including the electrical conductivity, Seebeck coefficient and thermal conductivity, were measured from 323 to 973 K. The thermoelectric properties depended on the holding time. The highest ZT value of 0.19 at 973 K was obtained for the sample with a 12 h holding time.