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Resistive random-access memory (RRAM) is a promising technology to develop nonvolatile memory and artificial synaptic devices for brain-inspired neuromorphic computing. Here, we have developed a STO:Ag/SiO2 bilayer based memristor that has exhibited a filamentary resistive switching with stable endurance and long-term data retention ability. The memristor also exhibits a tunable resistance modulation under positive and negative pulse trains, which could fully mimic the potentiation and depression behavior like a bio-synapse. Several synaptic plasticity functions, including long-term potentiation (LTP) and long-term depression (LTD), paired-pulsed facilitation (PPF), spike-rate-dependent-plasticity (SRDP), and post-tetanic potentiation (PTP), are faithfully implemented with the fabricated memristor. Moreover, to demonstrate the feasibility of our memristor synapse for neuromorphic applications, spike-time-dependent plasticity (STDP) is also investigated. Based on conductive atomic force microscopy observations and electrical transport model analyses, it can be concluded that it is the controlled formation and rupture of Ag filaments that are responsible for the resistive switching while exhibiting a switching ratio of ~103 along with a good endurance and stability suitable for nonvolatile memory applications. Before fully electroforming, the gradual conductance modulation of Ag/STO:Ag/SiO2/p++-Si memristor can be realized, and the working mechanism could be explained by the succeeding growth and contraction of Ag filaments promoted by a redox reaction. This newly fabricated memristor may enable the development of nonvolatile memory and realize controllable resistance/weight modulation when applied as an artificial synapse for neuromorphic computing.

We propose a highly tunable $$100\%$$ 100 % spin-polarized current generated in a spintronic device based on a Dirac semimetal (DSM) under a magnetic field, which can be achieved merely by controlling electrical parameters, i.e. the gate voltage, the chemical potential in the lead and the coupling strength between the leads and the DSM. These parameters are all related to the special properties of a semimetal. The spin polarized current generated by gate voltage is guaranteed by its semimetallic feature, because of which the density of state vanishes near Dirac nodes. The barrier controlled current results from the different distance of Weyl nodes generated by the Zeeman field. And the coupling strength controlled spin polarized current originates from the surface Fermi arcs. This DSM-based spintronic device is expected to be realized in $$\hbox {Cd}_{3}\hbox {As}_{2}$$ Cd 3 As 2 experimentally.

PurposeThe purpose of this paper is to investigate the effect of the soft annealing time on the microstructure and hydrogen embrittlement (HE) of Fe-0.22C-11.54Mn-2.05Al steels.Design/methodology/approachSteels A and B with different morphologies were prepared by cold rolling after warm rolling, long/short softening annealing and finally annealing at 700 °C for 30 min. Uncharged and charged samples were subjected to tensile, and HE behavior was studied by electron backscattered diffraction, scanning electron microscopy and X-ray diffraction.FindingsThe two samples exhibited similar tensile strengths. The homogeneous equiaxed microstructure of steel B was found to be more conducive to relieve its HE sensitivity. Steel A exhibited bimodal-grained microstructures – blocky and lath. The formation of crack in the blocky grains of steel A resulted in a significant reduction in its plasticity and tensile strength.Originality/valueThe high HE susceptibility of steel A is mainly connected with the inhomogeneity of martensite transformation.

The 4H-SiC trench metal–oxide semiconductor field-effect transistor (MOSFET) with the grounded p+ shielding region is one of the commercial devices with superior gate oxide reliability. However, the introduced JFET region seriously increases the influence of quasisaturation (QS) on device electrical performances, resulting in the poor output and transfer characteristics. In order to investigate the mechanism of QS effect, the output characteristic is physically analyzed by monitoring the variations of the electric field, the electron concentration, the electron velocity, and the depletion layer inside the cell structure. It is demonstrated that the channel electrons are injected into the JFET current path from the channel region by a forward bias to the channel and JFET junction at QS state. Moreover, based on the Lombardi CVT model, the influence of QS effect on devices with different channel electron mobilities is first studied. An improved SiC trench MOSFET with two-level doped current spreading layers is proposed to decrease the JFET resistance and suppress the QS effect. The QS current and the peak transconductance are improved by 42% and 23%, respectively. The specific ON-state resistance is decreased by 10% and the figure of merit is improved by 7%.

Conform and non-conformal contact problem in the face of piezoelectric motors can be hard to grasp, especially both the friction drive and wear lifespan are considered. Flowing the classical contact issue, an elastic brittle flat punch as the driving tip of the stator for piezoelectric devices is chosen and the contact behaviour under elliptical ultrasonic vibration is investigated using finite element method. A limited stress analysis is conducted after the quasi-static contact of the driving tip and the slider of the linear ultrasonic motors. After the analytical traces and experimental test on the fracture failure induced by the stress actions, the failure criteria of the elastic brittle driving tip are discussed. Results show that this quasi-static method can be applied to the complex contact analysis of an elliptical vibration device, and the failure characteristics induced by stress and strain can be obtained by FEM simulation and experiment verification. The pre-fracture stress map provides an important basis for the design of the geometrical mutation edge (e.g. edge fillet) of the elastic brittle punch and the composite structure for strength capacity. The failure analysis of brittle materials under ultrasonic vibration requires attention on quasi-brittle and quasi-plastic strength criterions. This study focus on determination of the contact stresses and the limited states during the elliptical vibration of a stator tip against slider. It also is important for the analysis on failure modes of frictional materials of ultrasonic devices, fretting wear of high-frequency connecting parts and machining process assisted with ultrasonic vibration.

Due to a special pathological type of triple-negative breast cancer (TNBC) and the lack of expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her 2), targeted therapies are not effective. The lack of effective treatment drugs and insensitivity to the current single-treatment methods are the biggest problems that we face with the TNBC treatment. Therefore, new strategies to achieve selective treatment and further visual efficacy evaluation will be powerful tools against TNBC. Herein, a novel tumor-targeted nanosized ultrasound contrast nanobubble loaded with chlorin e6 (Ce6), metformin (MET), and perfluorohexane (PFH) and covalently connected to the anti-PD-L1 peptide (DPPA-1) in the outer shell was fabricated. When accumulated in acidic tumor tissues, poly(ethylene glycol) (PEG) ligands detach, and DPPA-1 is exposed for programmed death-ligand 1 (PD-L1) targeting and blocking. The released metformin can relieve hypoxia by inhibiting mitochondrial complex I in the tumor microenvironment (TME) and enhance the therapeutic efficacy of Ce6 while synergizing with DPPA-1 by reducing PD-L1 expression. More significantly, photodynamic therapy (PDT) using multifunctional tumor-targeted nanosized ultrasound contrast agents (PD-L1-targeted pH-sensitive chlorin e6 (Ce6) and metformin (MET) drug-loaded phase transitional nanoparticles (Ce6/MET NPs-DPPA-1)) combined with PD-L1 checkpoint blocking can not only reduce tumor-mediated immunosuppression but also produce strong antitumor immunity. This finding provides a new idea for constructing multifunctional TNBC therapeutic nanoagents.

Practical application of surface-enhanced Raman spectroscopy (SERS) is greatly limited by the inaccurate quantitative analyses due to the measuring parameter's fluctuations induced by different operators, different Raman spectrometers, and different test sites and moments, especially during the field tests. Herein, we develop a strategy of quantitative SERS for field detection via designing structurally homogeneous and ordered Ag-coated Si nanocone arrays. Such an array is fabricated as SERS chips by depositing Ag on the template etching-induced Si nanocone array. Taking 4-aminothiophenol as the typical analyte, the influences of fluctuations in measuring parameters (such as defocusing depth and laser powers) on Raman signals are systematically studied, which significantly change SERS measurements. It has been shown that the silicon underneath the Ag coating in the chip can respond to the measuring parameters' fluctuations synchronously with and similar to the analyte adsorbed on the chip surface, and the normalization with Si Raman signals can well eliminate the big fluctuations (up to 1 or 2 orders of magnitude) in measurements, achieving highly reproducible measurements (mostly

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

The film flow and surface renewal of highly viscous liquid on a rotating spoked disk were investigated experimentally and numerically. In practical applications, the liquid is a polycarbonate melt with very high viscosity and Newtonian behavior at low shear rates. In the experiments, a maltose solution was used. The film thickness on the rotating disk was measured by an electrical conductivity probe. The Volume of Fluid (VOF) model combined with the sliding mesh method was used to simulate the film formation process. The simulated dimensionless film thickness and the film formation process agree well with the experimental results. The film flow and surface renewal under different operation conditions were evaluated. Gravity and viscous forces dominate the process with inertia playing a marginal role. A scraper was designed to intensify transfer processes on the film significantly.

To ensure the effective bonding of each structural layer of pavement and improve the service quality and durability of pavement, the waterborne epoxy resin (WER) emulsified asphalt (WEREA) tack coa...

In this paper, the ion substitution mechanism of CsPbIBr2 films prepared by a drop-coating method is studied. CsI/CsBr methanol solution is drop-coated on a CsPbIBr2 precursor film to prepare the C...

The failure mechanism of double-trench silicon carbide (SiC) power metal–oxide–semiconductor field-effect transistors (MOSFETs) under single-pulse avalanche stress is verified. Instead of the widely reported burning out failure mechanism for planar-gate devices, double-trench SiC power MOSFETs suffer from a totally different failure mechanism, as they can only endure a much lower maximum single-pulse avalanche energy ( $E_{\mathrm{ as}}$ ). It is found that during the avalanche process, obvious gate leakage current ( $I_{g}$ ) appears, which is resulted from the high impact ionization rate and high electric field along the gate trench bottom oxide interface, especially the trench corners. The $I_{g}$ continuously grows along with the increase in the peak load current ( $I_{\mathrm{ peak}}$ ), eventually leading to the breakdown of the trench bottom gate oxide under avalanche status. By increasing the value of gate resistor ( $R_{g}$ ), the $I_{g}$ raises the gate–source voltage ( $V_{\mathrm{ gs}}$ ) during the avalanche process, forcing the channel region in an inversion state. Part of the avalanche current is then diverted into the forward conductive current, changing the failure mode from breakdown of the gate oxide to burning out of the entire device. Moreover, the influence of different avalanche stress conditions, including the di / dt and the ambient temperature ( $T_{a}$ ), on the single-pulse avalanche endurance capability of double-trench SiC power MOSFETs is investigated. All the samples express a similar failure phenomenon. The higher the di / dt is, the shorter the avalanche time the device can endure. This is because the higher $I_{\mathrm {peak}}$ results in a higher $I_{g}$ during the avalanche process, leading to early failure of the gate oxide. However, the $T_{a}$ rarely influences the $E_{\mathrm{ as}}$ of the device, indicating that the single-pulse avalanche-induced failure of double-trench SiC power MOSFETs has little business with the melting of the lattice or package, demonstrating the correctness of the failure mechanism proposed in this article.

Paclitaxel (PTX) is a first-line chemotherapeutic agent to treat prostate cancer (PCa), but a large number of patients acquired drug resistance after short-term treatment. To develop combinational therapeutics to overcome PTX-resistant PCa, we established PTX-resistant LNCaP (LNCaP/PTX) cells and found that the LNCaP/PTX cells exhibited epithelial-mesenchymal transition (EMT) and enhanced metastasis during the selection process. We revealed that β-tubulin III, androgen receptor, and CXCR4 expressions were significantly increased in LNCaP/PTX cells and directly contributed to PTX resistance and EMT. Therefore, we developed prostate-specific membrane antigen aptamer (Apt)-functionalized shell-core nanoparticles (PTX/siRNAs NPs-Apt); the hydrophobic DSPE encapsulating PTX formed the dense inner core and the hydrophilic Apt-PEG2K with calcium phosphate (CaP) absorbing siRNAs formed the outer shell to sequentially release siRNAs and PTX, where CaP could trigger lysosomal escape to ensure that pooled siRNAs efficiently released into the cytoplasm to reverse EMT and resensitize PTX, while the PTX located in the core was subsequently released to exert the killing effect of chemotherapy to achieve the best synergistic effect. PTX/siRNAs NPs-Apt showed an enhanced tumor-targeting ability and achieved superior efficacy in the subcutaneous and orthotopic PCa tumor model with minimal side effects.

Humidity of proton exchange membrane fuel cell, a critical underlying variable that affects stack efficiency and durability, is quite challenging to be well controlled due to the measuring difficulty and multiple couplings with other variables. For precise humidity description and control, this paper utilizes the internal water content as the feedback signal, whose dynamic model is developed by taking into account various auxiliary couplings. Based on the mechanistic model, the dynamic responses of the internal water content are exhibited and analyzed by manipulating the external current, air compressor voltage and humidifier electrical power, respectively. It is shown that the internal water content is able to better describe the real humidity environment, in contrast with the conventional method using cathode inlet relative humidity. Furthermore, a combined feed-forward and feedback control structure is proposed to maintain the internal humidity as close to the desired as possible. Simulation results show that the proposed control method is able to maintain the fuel cell operating within the safe and efficient region, and the humidification power consumption can be reduced because of the precise and less conservative description on the internal humidity.

We devised a new self-assembly method towards the construction of molecular materials via a “wheel mounting” mode of [Ti3M] (M = Co or Zn) clusters. Assembly of these clusters was designable and customizable into desirable size, shape, and properties. An optical-driven molecular transition was realized with the stimulus–response of photochromism. This work not only provides an approach towards predictable and designable clusters, it also establishes a cluster-based structural model of molecular materials.

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

During the detection of formaldehyde, sensitivity and selectivity is still a challenging issue for most reported gas sensors. Herein, an alternative formaldehyde chemosensor that is based on porous ZnSnO3 nanocubes was synthesized. The products are characterized by XRD, SEM, TEM (HRTEM), XPS, PL measurements and N2 adsorption–desorption. The size of the ZnSnO3 nanocubes is about 100 nm and the corresponding specific surface area is 70.001 m2 g−1. A gas sensor based on these porous ZnSnO3 nanocubes shows high sensitivity and selectivity to formaldehyde. The porous ZnSnO3 nanocube sensor could detect 50 ppm formaldehyde at about 210 °C with a response value of 21.2, which is twice as much as ethanol, and 3 times that of the other five gases. Moreover, the response of the sensor had an acceptable change after a pulse test for 90 days. The sensor can detect formaldehyde with a minimum concentration of 1 ppm, and it has a good linear relationship between 1–50 ppm formaldehyde. The gas sensor based on porous ZnSnO3 nanocubes can be utilized as a promising candidate for a practical detector of formaldehyde due to its high gas response and excellent selectivity.

The purpose of the study is to clarify the curing effect of raw material composition on waterborne epoxy resin, thereby further improving working performance of waterborne epoxy resin. Based on the...

Problematic fouling along with wetting of membrane represent the main barriers for large-scale application of this technology. To solve the above problems and reinforce the anti-pollution and anti-wetting features of the distilling membrane, a brand-new TiO2 nanorods and 1H,1H,2H,2H-perfluorodecylsilane-triethoxy (PDTS) modified alumina hollow ceramic membrane with superhydrophobic surface and self-cleaning property was prepared for utilization in the vacuum membrane distillation. To synthesize the novel membrane, a seed layer was supported on the hollow ceramic membrane by the immersion-calcination method. Then, the TiO2 nanorods were grown on the membrane by hydrothermal method and annealed to strengthen the crystal structure. Finally, the nanorod-grown membrane was immersed in an alcohol solution of PDTS for hydrophobic treatment. The resulted modified membrane was applied to the distillation process to treat 100 g L−1 of concentrated brine for 3 h. It was revealed that the modified membrane possessed with a lower ionic conductivity under 20 µs.cm−1 of the permeated liquid and desirable surface superhydrophobicity at appropriate water contact angle of 152°, thus showing great promise for use in the membrane distillation process.

Technological miniaturization has enabled the development of small satellites weighing as little as 1 kg. Unfortunately, there is still a lack of suitable efficient micropropulsion systems at these scales. The pulsed plasma thruster is a structurally simple form of electric propulsion. This simplicity also makes it ideally suited for miniaturization. Its history can be traced back to applications in satellites that are much larger than micro/nano-satellites. The vast majority of modern pulsed plasma thrusters use solid polytetrafluoroethylene (PTFE) as a propellant. Unfortunately, at lower discharge energy levels such as those necessitated by the power limitations of micro/nano-satellites, PTFE has a tendency to exhibit carbon deposition, which can ultimately lead to thruster failure. In this new era of small satellites, it is important to consider alternative propellants in the miniaturization of pulsed plasma thrusters. This brief review discusses the needs and limitations of small satellites and alternative propellants that may be able to meet these needs. Such propellants may be able to offer advantages such as a longer thruster lifetime, a higher specific impulse, or a higher thrust-to-power ratio. This would enable the development of different types of pulsed plasma thrusters that can be tailored towards specific mission requirements.

The present research work is aimed to investigate the effect of infill pattern, density and material types of 3D printed cubes under quasi-static axial compressive loading. The proposed samples were fabricated though 3D printing technique with two different materials, such as 100% polylactic acid (PLA) and 70% vol PLA mixed 30% vol carbon fiber (PLA/CF). Four infill pattern structures such as triangle, rectilinear, line and honeycomb with 20%, 40%, 60%, and 80% infill density were prepared. Subsequently, the quasi-static compression tests were performed on the fabricated 3D printed cubes to examine the effect of infill pattern, infill density and material types on crushing failure behaviour and energy-absorbing characteristics. The results revealed that the honeycomb infill pattern of 3D printed PLA cubic structure showed the best energy-absorbing characteristics compared to the other three infill patterns. From the present research study, it is highlighted that the proposed 3D printed structures with different material type, infill pattern and density have great potential to replace the conventional lightweight structures, which could provide better energy-absorbing characteristics.

Metal organic frameworks (MOFs) has been considered as an ideal molecular capture material and has been widely used in many fields, including storage, catalytic, drug delivery and molecular separation due to its unique porous structure. MOFs contain organic linkers and metallic nodes, in which the aromatic ligands of MOFs have a strong π-π interaction with the aromatic structure of many organics, and the metal nodes are conducive to the coordination adsorption of the polarized parts of the molecule. Therefore, MOFs has a broad application prospect in the molecular detection field. Especially in recent years, researchers have continuously reported a series of SERS-active MOFs, which enriches the scope of metal-free semiconductor SERS platforms. In this study, MIL-100(Fe) was synthesized via hydrothermal method following the reported procedure with slight modifications, and then was characterized by scanning electron microscope (SEM), powder X-ray diffraction (PXRD) and porosity analyzer. Upon the adsorption of methyl blue (MB) and methylene orange (MO) onto MIL-100(Fe), different adsorption capability of MIL-100(Fe) to dyes were observed from their adsorption behavior curves. We found for the first time that MIL-100(Fe) can serve as an ideal SERS-active substrate for the capture and recognition of MB and MO but with different detection limits, 10−7 mol/L for MB and 10−5 mol/L for MO, respectively, indicating MIL-100(Fe) presents selective enhancement properties for these two organic dye molecules. In order to further increase the sensitivity of MIL-100(Fe) substrate for MO detection, the detection has been accomplished by depositing concentrated gold nanoparticle colloid onto the MIL-100(Fe) substrate, thus forming SERS “hot spots” which enable amplify the Raman signal of MO due to the electromagnetic enhancement (EM) effect. Density functional theory (DFT) was carried out to evaluate the binding position, molecular distance, binding energy and energy gap between dyes molecules and MIL-100(Fe). The energy gap between the MB and MIL-100(Fe) levels is 1.59 eV, close to the laser excitation energy ( E L=1.58 eV). This resonance suggests that the chemical enhancement (CE) mechanism may be operating, accounting for the high SERS activity of MIL-100(Fe) in MB detection. In addition, the adsorption energy between MB and MIL-100(Fe) is stronger than that of MO, this together with the CE accounts for the selective enhancing effect of MIL-100(Fe) on the two dye molecules.

Here, we report a nanocomposite with excellent photothermal performance promising for photothermal treatment. This nanocomposite is prepared by linking Au nanorods (NRs) to NaGdF4:18% Yb3+, 2%Er3+@...

The application of metal-organic frameworks (MOFs) as SERS-active platforms in multiplex volatile organic compounds (VOCs) detection is still unexplored. Herein, we demonstrate that MIL-100 (Fe) serves as an ideal SERS substrate for the detection of VOCs. The limit of detection (LOD) of MIL-100(Fe) for toluene sensing can reach 2.5 ppm, and can be even further decreased to 0.48 ppb level when "hot spots" in between Au nanoparticles are employed onto MIL-100 (Fe) substrate, resulting in an enhancement factor of 1010 . Additionally, we show that MIL-100(Fe) substrate has a unique "sensor array" property allowing multiplex VOCs detection, with great modifiability and expandability by doping with foreign metal elements. Finally, the MIL-100(Fe) platform is utilized to simultaneously detect the different gaseous indicators of lung cancer with a ppm detection limit, demonstrating its high potential for early diagnosis of lung cancer in vivo.

During the detection of industrial hazardous gases, like formaldehyde (HCHO), the selectivity is still a challenging issue. Herein, an alternative HCHO chemosensor that based on the tin oxide nanoparticles is proposed, which was obtained through a facile hydrothermal method. Gas sensing performances showed that the optimal working temperature located at only 180 °C, the response value of 79 via 50 ppm HCHO was much higher than that of 35 at 230 °C. However, the compromised test temperature was selected as 230 °C, taking into account the faster response/recovery speeds than 180 °C, named 20/23versus 53/60 s, respectively. The response (35) of the SnO2 nanoparticles-based sensor to 50 ppm of HCHO is about 400% higher than that of bulk SnO2 sensor (9), especially when the gas concentration is 1 ppm, SnO2 nanoparticles also has a higher sensitivity which may possibly result from more exposed active sites and small size effect for nanoparticles than for bulk ones. The gas sensor based on SnO2 nanoparticles can be utilized as a promising candidate for practical low-temperature detectors of HCHO due to its higher gas response, excellent response–recovery properties, and perfect selectivity.

The unexpected resistance reduction effect of double-trench SiC MOSFETs under repetitive avalanche stress is investigated in this work. After enduring repetitive avalanche stress, the ON-state drain-source resistance (Rdson) of the device decreases. With the help of TCAD simulations, the dominant mechanism is proved to be the injection of positive charges into the gate trench bottom oxide, which is almost irreversible under zero-voltage bias condition at room temperature. For the injected positive charges attract extra electrons just beneath the gate trench bottom, where the carriers pass through under ON state, the resistivity there is reduced, improving the conduction capability of the device. Moreover, an optimization method is proposed. Since the impact ionization rate (I.I.) and the vertical oxide electric field (E⊥) along the gate trench bottom oxide interface contribute to the injection of positive charges, it is recommended to make the bottom oxide thicker to suppress this effect.

The crystallization behavior, melting characteristics, and semicrystalline morphologies of wollastonite-filled recycled polypropylene (R-PP) composites without and with β-nucleating agent were investigated in this study. The crystallization temperature (Tc) of 20 mass% wollastonite-filled R-PP composite is 0.4 °C higher than that of R-PP, suggesting that the adding of wollastonite has little nucleation effect on crystallization of R-PP. However, 0.3 mass% TMB-5 significantly increases the Tc of R-PP and induces a large number of β-crystals in wollastonite-filled R-PP composites. For calcium pimelate-supported wollastonite (β-W) filled R-PP composites, the Tc and the relative β-phase content of R-PP increase with increasing addition amount of β-W (from 1 to 20 mass%). As a result, wollastonite-filled R-PP composites with β-phase content higher than 85% can be obtained by adding 0.3 mass% TMB-5 or 20 mass% β-W, which provides an effective method for realizing high value-added and low-cost recycling of R-PP.

Lead oxide (PbO) nanosheets are of significance in the design of functional devices. However, facile, green, and fast fabrication of ultrathin and homogenous PbO nanosheets with a chemically clean ...

Accurate and efficient gas monitoring is still a challenge because the existing sensing techniques mostly lack specific identification of gases or hardly meet the requirement of real-time readout. Herein, we present a strategy of conductometric response-triggered surface-enhanced Raman spectroscopy (SERS) for such gas monitoring, via designing and using ultrathin oxide-wrapped plasmonic metal nanoparticles (NPs). The oxide wrapping layer can interact with and capture target gaseous molecules and produce the conductometric response, while the plasmonic metal NPs possess strong SERS activity. In this strategy, the conductometric gas sensing is performed throughout the whole monitoring process, and once a conductometric response is generated, it will trigger SERS measurements, which can accurately recognize molecules and hence realize gas monitoring. The feasibility of this strategy has been demonstrated via using ultrathin SnO2 layer-wrapped Au NP films to monitor gaseous 2-phenylethanethiol molecules. It has been shown that the monitoring is rapid, accurate, and quantifiable. There exist optimal values of working temperature and SnO2 layer thickness, which are about 100 °C and 2.5 nm, respectively, for monitoring gaseous 2-phenylethanethiol. The monitoring signal intensity has a linear relation with the gas concentration in the range from 1 to 100 ppm on a logarithmic scale. Furthermore, the monitoring limits are at the ppm level for some typical gases, such as 2-phenylethanethiol, cyclohexanethiol, 1-dodecanethiol, and toluene. This study establishes the conductometric response-triggered SERS, which enables accurate gas recognition and real-time monitoring.

The purpose is to clarify the effect of warm-mix modifier on rheological properties of SBS warm-mix modified asphalt and its viscosity reduction mechanism. Different types of SBS warm-mix modified ...

A novel confined nitride (SiN) charge trapping 3-D NAND flash with excellent postcycling retention performances was demonstrated. Using a uniform sidewall lateral recess in the 3-D stack followed by a SiN pull-back process to isolate the SiN trapping layer in a self-aligned way is critical to facilitate this structure. Lower erase saturation ${Z}$ -direction. Therefore, this structure is in favor of the larger memory window (>10 V) design. Random telegraph noise (RTN) characteristics are comparable to the traditional 3-D NAND device with 100 years at 60 °C and even longer at room temperature. Moreover, superior post-1K-cycled multilevel cell (MLC) retention was also illustrated, which even sustains 150 °C and one-week baking. Therefore, the device has the potential to meet the low-cost long-retention archive memory applications.

The optimal excitation wavelength (OEW) for surface-enhanced Raman spectroscopy (SERS) is generally close to that of the local surface plasmon resonance (LSPR). In some cases, however, the OEW is significantly longer than that of the observed LSPR. Its origin is still unclear and controversial. Here, we propose a chemical interface damping (CID)-based mechanism and reveal the origin of the OEW's deviation from the LSPR by simulation and experiments using gold nanorods as the model material. Simulations show that the molecular adsorption induces CID, which causes a red-shift of the near-field peak relative to the far-field one, and that the chemical adsorption of target molecules on the plasmonic metals with enough strong CID would induce a significant red-shift of the OEW, even to the region far beyond the LSPR. Finally, we experimentally confirm the validity of the proposed CID theory and demonstrate the significant influence of the CID on the OEW during SERS measurements.

It is well known that magnetic nanofluids are widely applied in various fields ranging from heat transfer to miniature cooling, and from damping to sealing, due to the mobility and magnetism under magnetic field. Herein, the PFPE-oil based magnetic nanofluids with superior magnetization and dispersion stability were obtained via regulating reaction temperature. The structures of particles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The size effects of particles on the magnetism and coating effect of particles, and on the stability and saturation magnetization of the fluids were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM) and density instrument, respectively. The results indicate that the impurity phase FeOOH only appear in the sample prepared at 18°C and the average size of Fe3O4 nanoparticles reduces from 120 to 20 nm with raising reaction temperature. The saturation magnetization of Fe3O4 particles increases firstly and then reduces with increasing particle size, which is affected by the thickness of magnetic dead layer and impurity phase FeOOH. The Fe3O4 particles could be chemically coated by PFPE-acids, and the coated mass is a little affected by particle size. The stability of the nanofluids lowers while the saturation magnetization increases firstly and then decrease with increasing particle size. At reaction temperature of 60°C, Fe3O4 particles of 25 nm and the nanofluids with superior stability and saturation magnetization were obtained. Our results indicate that the control of nanoparticles size by regulating reaction temperature can be a useful strategy for preparing magnetic nanofluids with desirable properties for various potential applications.

The linear convective instability of a mixture of dry air, water vapour and liquid water, with a stable unsaturated layer residing on an unstable saturated layer, is studied. It may serve as a prototype model for understanding the instability that causes mixing at the top of stratocumulus cloud or fog. Such a cloud-clear air interface is modelled as an infinitely thin saturation interface where radiative and evaporative cooling take place. The interface position is determined by the Clausius–Clapeyron equation, and can undulate with the evolution of moisture and temperature. In the small-amplitude regime two physical mechanisms are revealed. First, the interface undulation leads to the undulation of the cooling source, which destabilizes the system by superposing a vertical dipole heating anomaly on the convective cell. Second, the evolution of the moisture field induces non-uniform evaporation at the interface, which stabilizes the system by introducing a stronger evaporative cooling in the ascending region and vice versa in the descending region. These two mechanisms are competing, and their relative contribution to the instability is quantified by theoretically estimating their relative contribution to buoyancy flux tendency. When there is only evaporative cooling, the two mechanisms break even, and the marginal stability curve remains the same as the classic two-layer Rayleigh–Bénard convection with a fixed cooling source.

The MnO/C composites were obtained by co-precipitation method, which used Mn3O4 nanomaterials as precursors and dopamine solution after ultrasonic mixing and calcination under N2 atmosphere at different temperatures. By studying the difference of MnO/C nanomaterials formed at different temperatures, it was found that with the increase of calcination temperature, the materials appear obvious agglomeration. The optimal calcination temperature is 400 °C, and the resulting MnO/C is a uniformly dispersed slender nanowire structure. The specific capacitance of MnO/C nanowires can reach 356 F g−1 at 1 A g−1. In the meantime, the initial capacitance of MnO/C nanowires remains 106% after 5000 cycles. Moreover, the asymmetric supercapacitor was installed, which displays a tremendous energy density of 30.944 Wh kg−1 along with a high power density of 10 kW kg−1. The composite material reveals a promising prospect in the application of supercapacitors.

In this work, titanium-capped cobalt clathrochelates have been applied as secondary building units (SBUs) for the construction of supramolecular rings. Two heterometallic wheel-like [Ti6Co12] complexes based on cobalt clathrochelates, [C6H15N4]2[TiCo2(μ2-Oipr)(Oipr)2(Dmg)3]6 (2, Dmg = dimethylglyoxime) and H6[TiCo2(μ2-Oipr)(Oipr)2(Dmg)3]6 (3), have been successfully synthesized and characterized. The supramolecular stacking modes of these wheels are largely dependent on the applied synthetic conditions, which further impact their gas adsorption properties.

Blackening (or enhancing the optical absorption in the visible region) of nano-sized white semiconducting oxides (N-WSOs) is of significant importance for solar utilization. Here, we present a novel Mars-van-Krevelen mechanism-based method for blackening the N-WSOs via facile one-step heating of the N-WSOs with alcohols. Taking n-butanol-induced blackening of TiO2 (anatase) as an example, the pristine TiO2 NP powders can be successfully blackened to form black TiO2 (B-TiO2) via heating with n-butanol at 300 °C for 20 min. Technical analyses demonstrate that the B-TiO2 nanocrystals are wrapped with a 2 nm thick disordered layer, which is rich in oxygen vacancies, Ti3+ and hydroxyl groups. Both theoretical and experimental results show that B-TiO2 has much stronger optical absorption in the visible region than pristine TiO2. Furthermore, the influence factors (including heating temperatures and alcohol types) and good universality of this blackening method are also demonstrated. A blackening principle based on Mars-van-Krevelen mechanism-induced oxygen vacancy generation and hydroxylation-anchoring of oxygen vacancies has been proposed, and the mechanism can well explain all the phenomena observed in experiments. Importantly, such B-TiO2 shows hugely enhanced activity in solar photodegradation of dye pollutants. Under simulated solar irradiation, the degradation rate constant achieved by the B-TiO2 catalyst is 2.3 times that of the pristine TiO2, showing an obvious enhancement. Further experiments reveal that the improved degradation activity is mainly attributed to the enhanced optical absorption in the visible region and the synergistic photothermal and photocatalytic effect. This study demonstrates a new and facile approach to blacken the N-WSOs for enhanced solar utilization.

Lattice modification by Li+ doping has been an effective method to manipulate the optical property of lanthanide-doped phosphors, but it lacks an understanding for the highly anisotropic layered host connected by van der Waals forces. In this work, based on BiOCl layered crystals prepared by the solid-state method, we systematically studied the doping mechanism of Li+ ions and its effects on the luminescence properties of Eu3+ activators. The experiment and calculation results indicated that high-concentration Li+ ions can be incorporated into the lattice interlayer by van der Waals forces rather than into substitutional or interstitial sites. Moreover, Li+ ion dopants greatly decrease the crystallinity of BiOCl samples but improve their interlayer electrostatic potential and spontaneous internal electric field (IEF). When the doping concentration increased to 30% moles, the emission intensity of Eu3+ ions under host excitation is enhanced by at least 5 times, accompanied with the prolonged decay time. With the interlayer doping of Li+ ions, the local field effect and photocarrier separation role of the enhanced IEF are responsible for the special photoluminescence properties of Eu3+ ions. The results of this paper not only contribute to understand the optical and structural properties of the layered phosphor system but also open up new ideas for the construction and design of efficient photonic materials.

Multinary copper-based chalcogenide nanocrystals (NCs) as light-driven photocatalysts have attracted extensive research interest due to their great potential for generating sustainable energy without causing environmental concerns. However, systematic studies on the growth mechanism and related photocatalytic activities involving different valent metal ions (either M2+ or N3+) as foreign cations and monoclinic Cu1.94S NCs as the ‘parent lattice’ have rarely been carried out. In this work, we report an effective seed-mediated method for the synthesis of heterostructured Cu1.94S–MS NCs (M = Zn, Cd and Mn) and alloyed CuNS2 NCs (N = In and Ga). A typical cation exchange process took place prior to the growth of heterostructured NCs, while further inter-cation diffusion occurred only for the alloyed NCs. When compared with Cu1.94S NCs, all the heterostructured Cu1.94S–MS NCs and CuGaS2 NCs showed enhanced photocatalytic activities toward hydrogen production by water splitting, owing to their tailored optical band gaps and energy level alignments. Although optically favored, CuInS2 ANCs were not comparable to others due to their low conduction band minimum for the reduction of H2O to H2.

Silver (Ag)-based Janus nanoparticles (NPs) are of broad interest for extensive applications due to their excellent photoelectric performances and special structure. However, it still remains chall...

An analytical model for the textured infinitely long slider is developed to study the influence of cross-hatched texture on hydrodynamic lubrication by considering the mass-conserving boundary condition. The three-dimensional morphology of the cross-hatched texture is characterized by a series of mathematical formulas. By using multigrid method and Gauss–Seidel iteration, the hydrodynamic pressure distribution of textured surface can be obtained to analyze the influence of width, depth, spacing, cross-hatched angle and overlapping coefficient of the cross-hatched texture on the hydrodynamic lubrication. The results show that hydrodynamic lubrication can be generated between two parallel plane surfaces with cross-hatched texture. Moreover, the geometrical parameters of the cross-hatched texture have prominent effect on hydrodynamic pressure distribution and load carrying capacity.

The effects of air, hydrogen, and CO 2 and O 2 mixture sintering atmospheres on the structure, micromorphology, electron emission capability and environmental stability of 612 type barium-calcium-aluminates have been investigated. Both the 6BaO-1CaO-2Al 2 O 3 aluminates sintered in air and hydrogen crystallize in the Ba 3 CaAl 2 O 7 phase. However, the aluminates with the same composition sintered in CO 2 and O 2 mixture crystallizes in the Ba 3 Al 2 O 6 phase with a small amount of BaCO 3 reactant. The microstructure for the aluminates sintered in air and H 2 show similar features while the sample sintered in CO 2 and O 2 mixture atmosphere shows better conglomeration. Emissivity tests indicate that the divergent current density J div for the dispenser cathodes impregnated with aluminates sintering in air, H 2 , and CO 2 and O 2 mixture atmospheres are 6.0, 6.1, and 7.6 A cm −2 at 1130 °C B , respectively. Finally, environmental stability tests indicate that the aluminates with the Ba 3 CaAl 2 O 6 phase sintered in air as well as hydrogen is more environmentally stable than that with Ba 3 Al 2 O 6 phase sintered in CO 2 and O 2 mixture. The process of sintering 612 aluminate in CO 2 and O 2 mixture is beneficial for superior emissivity on the condition of avoiding exposure to moisture.

SnO2-based materials are helpful to detect low concentration of volatile organic compounds (VOCs), whereas high operating temperatures (≥ 350 °C), poor selectivity and inadequate detection limit of the pristine SnO2 hinder their broader applications. An alternative strategy to address these challenge issues is to adopt porous SnO2 nanotubes (NTs) constructed with ultrathin walls to monitor VOCs. However, inconvenient synthetic routes and low-yield rate of NTs with satisfactory wall thickness restrained the application of SnO2 NTs. Herein, we directly turned SnS2 nanosheets to the porous SnO2 NTs by thermal oxidizing the SnS2 precursor in air. After thermal treatment, high crystallinity and porous hierarchical SnO2 NTs with ultrathin walls were successfully synthesized without any impurities. After decorated with Au nanoparticles (NPs), a strong interaction between the Au NPs and hierarchical SnO2 NTs was witnessed. Compared with those reported SnO2-based materials, hierarchical SnO2 NTs indeed improved the gas sensing properties; particularly, the sensor using Au-SnO2 NTs composite gave the largest sensing magnitude, satisfactory detection limit and high selectivity to acetone at operating temperature of 200 °C. Conclusively, the innovation of transforming SnS2 to the hierarchical SnO2 NTs paves the way to building SnO2 NTs from 2 dimensions ultrathin bricks, and for high performance sensing VOCs.

A facile and general strategy is presented for homogenous and ultrathin metal sulfide wrapping on plasmonic metal (PM) nanoparticles (NPs) based on a thiourea-induced isotropic shell growth. This strategy is typically implemented just via adding the thiourea into pre-formed PM colloidal solutions containing target metal ions. The validity of this strategy is demonstrated by taking the wrapped NPs with Au core and CuS shell or Au@CuS NPs as an example. They are successfully fabricated via adding the thiourea and Cu2+ solutions into pre-formed Au NP colloidal solution. The CuS shell layer is highly homogenous (

Abnormal wear sometimes occurs on the high speed train brake disc surface in winter time. In this paper, Co-based alloy powders were deposited by laser cladding technology to improve the wear resistance of train brake discs. Sliding wear at room temperature, 200 °C, 400 °C and 600 °C were conducted to investigate the wear behavior. Microstructure, hardness, and phase composition of Co06 cladding layers were also studied. The results showed that Co06 cladding layer exhibited better wear resistance than the substrate, with different wear mechanisms at high temperatures. Co06 cladding layers also exhibited better high temperature oxidation resistance than the substrate. Cr23C6 played a significant role in anti-friction.

Electronic structure, stability and bonding strength of α-Fe/WC interfaces between Ce-doped and undoped WC cermet coating were investigated by first-principles methodology based on density-functional theory (DFT). Based on the minimum mismatched lattices, the relatively stable interface that forms between WC (100) and bcc α-Fe (100) was employed to predict the atomic structure, bonding, and ideal work of adhesion. There are three possible positions which were defined as OT, MT, HCP, taking into account both C- and W-terminations. The sequence of structural stability tested in this paper was: MT > OT > HCP. After full relaxation, the results show that only the first and second layers of the interface have significant influence on the electronic structure between Fe and WC. The interaction of Ce elements at the interface is achieved by comparing the interface structure and electronic structure of the doped and undoped interfaces. Ce doped interface possesses a shorter interface distance (d0 = 0.09776 nm) and a larger interface energy (Wad = 8.98 J/m2) than undoped interface (Wad = 8.76 J/m2, d0 = 0.10134 nm).Charge density distribution and difference, and density of states were utilized to characterize the electronic properties and determine the interfacial bonding.The results demonstrate that strong covalent bonding existed in the undoped interface, while a mixed covalent/ionic bonding was formed at the Ce-doped interface.

In order to optimize the synthesis process of barium-calcium-aluminate (BCA) for the application of impregnated dispenser cathodes, the influence of two precipitants, ammonium carbonate (AC) and ammonium hydrogen carbonate (AHC), on the chemical composition, phase transformation, thermal behaviors and morphology of the precursors was systematically investigated by means of XRD, TG-DSC, FESEM, and EDS mapping analysis. The results revealed that AC precipitant facilities to form NH4Al (OH)2CO3 (AACH) phase and barium calcium carbonate in the precursor, while the product precipitated by AHC comprises amorphous γ-AlOOH phase and the carbonate. Both precursors precipitated by the AC and AHC undergo various stages of phase transformations and finally converted to an emission-active material Ba3CaAl2O7 phase after sintering at 1200 °C. DC emission current values have been measured and the maximum space charge limited current densities are 8.0 ± 0.3 and 6.5 ± 0.4 A/cm2 at 1130 °Cb for the testing cathodes impregnated with the AC and AHC precursor aluminates, respectively. The difference in the emission capacity originates from the barium content in the aluminates prepared with different precipitants.

Exploring high-performance sensing materials is ultra-important for safety control. Herein, 1D α-MoO3/0D ZnO nanocomposites are prepared via a facile hydrothermal method and its microstructure is characterized through X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS). It is confirmed that the as-prepared nanocomposites are constituted by 1D α-MoO3 nanobelts (200–300 nm in width), with the surface loaded with fine ZnO nanoparticles. Sensing properties of the α-MoO3 and 1D α-MoO3/0D ZnO nanocomposites to ethanol are measured and compared. Interestingly, the ZnO-decorated α-MoO3 nanobelts exhibited excellent sensitivity and selectivity to ethanol at relatively low operating temperature (250 °C) when compared with that of the raw α-MoO3 nanobelts, indicating a good candidate of 1D α-MoO3/0D ZnO nanocomposites for future ethanol detection.

To improve the road performance and heat resistance of thermal resistance aggregates, thermal resistance aggregates wrapped with organosilicon resin were prepared. The optimal surface treatment process of different thermal resistance aggregates was determined. The surface wrapping effect of different thermal resistance aggregates were evaluated based on the macropore structure and microsurface morphology. In addition, the road performance of different thermal resistance aggregates before and after surface treatment were compared and analyzed. The heat resistance performance of different thermal resistance asphalt mixtures was tested by an indoor sunlight simulation test. Furthermore, the effect of surface treatment on road performance and heat resistance of a thermal resistance asphalt mixture was evaluated. The results showed that the surface treatment of shale ceramsite with organosilicon resin achieved the best result. The 24 h oil absorption decreased to 2.05%. The surface pore sealing rate was as high as 78.3%, and the opening pores could hardly be seen in the SEM images. After being surface treated with organosilicon resin, the water absorption, crushing value and abrasion value of three kinds of thermal resistance aggregates decreased by 82.87%–94.50%, 6.8%–22.07% and 10.87%–28.56%, respectively, and their adhesion increased to grade 5. The surface treatment of thermal resistance aggregates could significantly improve the high temperature performance and water stability of thermal resistance asphalt mixtures. There was little effect on the low temperature performance, while the heat resistance performance of the thermal resistance asphalt mixture was improved to varying degrees.

The aim of this study is to improve the fundamental properties of refractory bauxite to promote its further application in the heat-resistant asphalt pavement technology. A method of coating refractory bauxite in an organosilicon solvent is proposed. The surface coating effects of different organosilicon solvents on high-alumina refractory bauxite are compared and evaluated using the macropore structure and the microsurface morphology. Based on the optimal treatment process and material proportion, the fundamental properties of different organosilicon–refractory bauxite materials are analyzed systematically. Based on the grey target decision-making method, the comprehensive performance of different organosilicon–refractory bauxite is evaluated. On this basis, the organosilicon–refractory bauxite material with better comprehensive performance was added into the asphalt mixture and its pavement performances were identified. The results show that a large number of pores of refractory bauxite are sealed by using organosilicon solvents. Moreover, the coating effect is good. In addition, the heat resistance is improved. The mechanical property and adhesion of refractory bauxite are increased by 30.66% and 66.67%, respectively.