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In this study, laser ablation-resistant composite coating consisting of zirconium diboride (ZrB2) particulate and silicon carbide (SiC) whisker with zirconia (ZrO2)-sol binder was prepared to meet requirements of anti-laser ablation ability. Laser ablation behavior of as-prepared coating was investigated under varying laser powers. Results revealed that the highest back-surface temperature of coated aluminum substrate was only 150 °C when irradiated at a power density of 6.3 kW/cm2 for 10 s, which is below the maximum allowable temperature of the aluminum alloy substrate (200 °C). After ablation for 10 s, the mass ablation rate of the composite coating was 4.45 mg/s. Apparently, the composite coating exhibited outstanding ablation resistance against high-intensity continuous laser irradiation. At initial stage of ablation, combination of self-healing effect of liquid ZrO2–SiO2 layer and volatilization of B2O3 provide effective joint protecting mechanism. With increasing ablation time, ZrO2 ceramic barrier layer, product of the pyrolysis of ZrO2 gel and ZrB2 filler, becomes progressively more important in maintaining excellent laser ablation resistance behavior, which is normally effective at around ablation pit.

In this study, N/O co-doped cage-type biomass carbon (NOBC) was prepared through a simple and facile hydrothermal reaction and two-step carbonization method. As the anode of a potassium ion battery, NOBC displays a superhigh long-cycling performance and a super high rate performance. NOBC-2 provides an excellent reversible capacity of 251.2 mAh g−1 after 1500 cycles at 0.5 A g−1, and an excellent performance of 334.6 mAh g−1 at a high current density of 5 A g−1 (after 2000 cycles). The reversible capacity of 124.19 mAh g−1 can be maintained even after 5000 cycles at 10 A g−1. The excellent performance of NOBC is attributed to the unique hollow cage structure, internal 3D carbon network structure and N/O co-doping. Based on the results of detailed fundamental analysis, the pseudo-capacitance mechanism contributes to the higher K ion storage process in NOBC-2. Density functional theory (DFT) calculations further show that N/O double doping can promote the adsorption of K ions in biomass carbon materials and improve the conductivity of the materials. The simple synthesis route and excellent electrochemical performance provide new insights for the search for novel carbon-based K storage anode materials with high energy and long cycle life.

One-dimensional (1D)–two-dimensional (2D) van der Waals (vdWs) mixed-dimensional heterostructures with advantages of an atomically sharp interface, high quality and good compatibility have attracted tremendous attention in recent years. Herein, a mixed-dimensional vertical heterostructure is constructed by transferring mechanically exfoliated 2D WS2 nanosheets on epitaxially grown 1D tellurium (Te) microwires. According to the theoretical type-II band alignment, the device exhibits a photovoltaic effect and serves as an excellent self-powered photodetector with a maximum open-circuit voltage (Voc) up to ∼0.2 V. Upon 635 nm light illumination, the photoresponsivity, external quantum efficiency and detectivity of the self-powered photodetector (SPPD) are calculated to be 471 mA W−1, 91% and 1.24 × 1012 Jones, respectively. Moreover, the dark current of the SPPD is highly suppressed to the sub-pA level due to the large lateral built-in electric field, which leads to a high Ilight/Idark ratio of 104 with a rise time of 25 ms and decay time of 14.7 ms. The abovementioned properties can be further enhanced under a negative bias of −2 V. In brief, the 1D Te–2D WS2 mixed-dimensional heterostructures have great application potential in high performance photodetectors and photovoltaics.

Coalbed methane is stored mainly in coal pores, and pore changes by fracturing fluid affect the extraction effect of coalbed methane. To select the optimal formulation of viscoelastic surfactant (VES) fracturing fluids, we treated coal samples of different hardness with deionized water (A) and three different fluids that contained cationic surfactants (B), mixed cationic and zwitterionic surfactants (C) and mixed anionic and zwitterionic surfactants (D) as the main agents. The effect of the three VES fracturing fluids on pores was compared quantitatively and on a multi-scale. The pore characteristics were tested by field emission-scanning electron microscopy, mercury intrusion capillary pressure and low-pressure nitrogen physisorption. Image-Pro Plus 6.0 software was used to digitize information from the obtained images. The Angulo and Frenkel–Halsey–Hill models were used to calculate the fractal dimension by using mercury intrusion capillary pressure and low-pressure nitrogen physisorption data, respectively. The effect of VES fracturing fluids B and D on pores from 14 nm to 180 μm was greater than that for VES fracturing fluid C as the main agent. The effect of VES fracturing fluid C on the pores (2–300 nm) was most obvious.

The design and preparation of powerful anode materials are key to developing potassium-ion batteries. A biomass-based potassium anode material with a distinct hollow-cage structure was prepared by one-step carbonization. The target carbon exhibited a specific surface area of 104.4 m2 g−1 and mesopores/macropores distributed materials. When used as the negative electrode of a potassium-ion battery, the cage-like porous carbon (CPC) showed a reversible capacity of 407 mAh g−1 after 50 cycles at 50 mA g−1 current density. After 100 cycles, at a current density of 200 mA g−1, the reversible capacity was 163.8 mAh g−1. It still exhibits an extremely long cycle stability at high current densities (discharge capacity of 124.6 mAh g−1 after 700 cycles at a current density of 1 A g−1). The excellent performance is attributed to the stable cage-like carbon scaffold and uniform continuous distribution of mesopores/macropores to improve ion diffusion kinetics and electronic conductivity. These results indicate that a properly designed CPC can effectively increase the capacity and cycle stability of a potassium-ion battery.

A three-dimensional mullite-whiskers network ceramic with ultra-light weight and high-strength was obtained by the foaming gel-casting method with active mulllite powders and NH4F. Ultrafine active mullite powder was used as the raw material and SDS (sodium dodecyl sulfate) as a pore-forming agent. The effects of sintering temperature on the microstructure, flexural strength and thermal conductivity of the porous ceramics were systematically investigated. The mullite-whisker network porous ceramic has a fibrous-framework structure composed of interweaving mullite-whiskers. Because the pore-walls are composed of interlacing whiskers and the pores are filled with whiskers, the porous ceramics exhibited good mechanical properties and low thermal conductivity. The flexural strength of the obtained mullite-whisker porous ceramic sintered at 1500°C was up to 1.45 Mpa, while the porosity was as high as 89%. In addition, the thermal conductivity of the porous ceramic at room temperature was as low as 0.045 W/m⋅K.

SiO2-MgO ceramics containing different weight fractions (0, 0.5, 1, 2, and 4 wt%) of SiO2 powder were prepared by mixing nano MgO powder, and the powder mixtures were densified by spark plasma sintering (SPS). The effect of SiO2 addition and SPS method on the sintering behavior, microstructure and mechanical properties were investigated. Results were compared to specimens obtained by conventional hot pressing (HP) under a similar sintering schedule. The highest relative density, flexural strength and hardness of 2 wt% SiO2-MgO ceramics reached 99.98%, 253.99 ± 7.47 MPa and 7.56 ± 0.21 GPa when sintered at 1400 °C by SPS, respectively. The observed improvement in the sintering behavior and mechanical properties are mainly attributed to grain boundary "strengthening" and intragranular "weakening" of the MgO matrix. Furthermore, the spark plasma sintering temperature could be decreased by more than 100 °C as compared with the HP method, SPS favouring enhanced grain boundary sliding, plastic deformation and diffusion in the sintering process.

The clogging mechanism has attracted increasing attention due to widespread applications of fibrous filtration in the industry. We carry out computational fluid dynamics with a discrete element method to investigate the clogging in a two-fiber system. The role of interparticle adhesion among microparticles in the unclogging-clogging transition is examined. A clogging phase diagram in the form of the Stokes number and the adhesion parameter (Ad) is built. We show that the formation of clogs contains two sequential processes, the growth of particle chain and the formation of bridges connecting two fibers. A stronger adhesion results in a longer growing time but a shorter bridging time of particle chains. These competing trends yield an “optimal” Ad range with the fewest penetrating particles. The structural analysis of the clogs shows that as Ad increases, the average local volume fraction and coordination number decrease. The reconstruction of particles mainly happens in the initial cake filtration stage.

Optimizing highly porous fibrous ceramics, like bird’s nest structure, were obtained by vacuum impregnation method with mullite fibers and alumina sol as raw material. The influences of impregnation cycles on the property of the sample, such as porosity, compressive strength and room-temperature thermal conductivity were explored. The experimental results show that the 3D skeleton structure of the sample was constructed by the randomly arranged mullite fibers and inorganic particles. The content of alumina can be adjusted effectively by impregnation times and it increases with increasing impregnation cycles. The thermal conductivity and compressive strength can also be controlled via tailored impregnation cycles. The compressive strength of fibrous ceramic ranged from 1.03 MPa to 5.31 MPa, while the porosity decrease slightly from 85.3% to 73.8%. In the same time, the thermal conductivity increase from 0.037 W/(m·K) to 0.217 W/(m·K), indicating that the fibrous ceramic with high impressive and low thermal conductivity can be fabricated by impregnation method.

Nitrogen doping in Bi-based oxides is highly desired due to the band gap tuning and chemisorption ability engineering. While it is rather difficult to incoporate nitrogen into Bi-based oxides because bismuth could be reduced easily during the high temperature synthesis process. In this work, we design a low temperature synthesis route to dope nitrogen into Bi-based Aurivillius phase compound Bi4Ti3O12 (BIT), which is a process of in-situ reaction, and the nitrogen doped Bi4Ti3O12 (N-BIT) particles have a similar morphology and structure to BIT. The positions of the substitutive nitrogen atoms in the N-BIT crystals are predicted to be at the oxygen atoms between the medial [TiO6] octahedron and the [TiO6] octahedron near the [Bi2O2]2+ layers and a smaller band gap of the N-BIT crystals is resulted by the first-principles calculations. The reduced band gap from BIT of 3.04 eV to N-BIT of 2.80 eV is confirmed by the absorption spectra measurements, which is benefical for charge separation under photoexcitaton. Furthermore, oxygen vacancies formed in the N-BIT sample due to the substitution of oxygen atoms with nitrogen atoms, gernerate more chemisorbed oxygens, which could be excited to the superoxide radicals. Therefore, the photocatalytic activity of N-BIT is enhanced after nitrogen doping.

Deep coal bed methane generally has a higher formation temperature than shallower coal, which can have important consequences for hydraulic fracturing. In this study, the pore characteristics of coal samples treated by viscoelastic surfactant (VES) fracturing fluid as a function of temperature (293.15–353.15 K) were qualitatively and quantitatively analyzed using mercury injection capillary pressure tests (MICP) and low-temperature N2 gas adsorption (N2GA). The Angulo model and Frenkel–Halsey–Hill (FHH) model were used to describe the fractal characteristics of the coal pores. The results indicated that VES fracturing fluid was most effective for pore changes at temperatures below 323.15 K. The mechanism of VES fracturing fluid on coal pores at variable temperatures was analyzed and addressed from two aspects: (1) the ability of fracturing fluid to enter pores and contact the pore surface; and (2) the ability of fracturing fluid to scavenge minerals on the pore surface. The wettability of VES fracturing fluid on pore surface was analyzed from the surface tension, carboxyl and hydroxyl groups of the coal. The influence of temperature on the solubility of minerals (e.g., calcite, kaolinite, and other inorganic minerals) in VES fracturing fluid was analyzed.

Curcumin is a natural active constituent with a great variety of beneficial biological and pharmacological activities, is a practically water-insoluble component. The scope of the present work was to prepare a solid dispersion (SD) formulation to enhance the dissolution rate of curcumin. The SD was prepared using curcumin and β-cyclodextrin (CD)/HA via a classical ethanol-based solvent evaporation method. The as-prepared β-CD/HA and SDs were selectively characterised by various analytical techniques including X-ray diffraction, transmission electron microscopy, scanning electron microscopy, specific surface area/pore size analysis, Fourier transform infrared spectroscopy, and high-performance liquid chromatography. According to the dissolution tests, it was confirmed that β-CD/HA–curcumin SD can significantly enhance the dissolution of curcumin. In addition, an increasing trend was seen between the β-CD weight ratio and the dissolution rate of curcumin, and β-CD/HA–curcumin (9:1) SD was shown to be the best formulation among all tested samples with over 90% curcumin dissolved in 180 min. Besides, β-CD/HA–curcumin (9:1) SD exhibited pH and medium-dependent curcumin release behaviours. The antioxidant activity of released curcumin showed no difference to original curcumin. These results clearly demonstrated β-CD/HA can be a promising SD carrier to improve the dissolution of curcumin.

Regulating the electronic structure of catalysts is the most efficient strategy yet, despite its limitations, to improve their oxygen evolution efficiency. Instead of only adjusting the electronic structure, here we utilize ferroelectric polarization to accelerate the oxygen evolution reaction as well. This is demonstrated on a multiferroic layered perovskite Bi5CoTi3O15 with in-situ grown BiCoO3. Thanks to the superimposed effects of electronic regulation and ferroelectric polarization, the as-prepared multiferroic electrocatalysts are more efficient than the benchmark IrO2 (with a final 320 mV overpotential at the current density of 10 mA cm−2 and a 34 mV dec−1 Tafel slope). This work not only demonstrates a low-cost and high-efficient OER electrocatalyst, but also provides a strategic design for multi-component electrocatalytic material systems by consideration of both spin and polarization degrees of freedom., While splitting water into fuel may provide a green, renewable method for energy storage, water oxidation is its bottleneck. Here, authors reported multiferroic electrocatalysts with improved oxygen evolution performances assisted by polarization.

We report the preparation of epoxy-based composites with enhanced dielectric properties and thermal conductivity, by employing intelligently designed core/shell Alumina/Polydopamine (indicated as AO*) and strawberry-like core/shell structured Alumina/Polydopamine/Silver (indicated as AO*@Ag) particles as fillers. The introduction of the core-shell AO* and AO*@Ag particles into the epoxy matrix can distinctly enhance both the dielectric permittivity and dielectric breakdown strength of composites, as compared to that incorporating AO particles as fillers. For example, the dielectric breakdown strength of AO*@Ag/epoxy with 22.9 vol% filler loading is up to 65.5 kV/mm, representing an improvement of 24% compared with AO/epoxy composite at the same filler loading (52.8 kV/mm), while it has enhanced dielectric permittivity at room temperature at low frequency. Additionally, the strawberry-like core/shell particle-filled composites still take on a high thermal conductivity.

We investigated the effects of $\text{Al}_{2}\mathrm{O}_{3}$ -capping layer diffusion between the interfacial layer (IL) and $\text{HfSiO}_{\mathrm{x}}$ dielectric in DRAM periphery transistor, mainly focusing on electrical performance variations by modulation of thickness and Hf content. Higher Hf content and appropriate $\text{Al}_{2}\mathrm{O}_{3}$ capping layer were found to be optimal for pMOSFET fabrication. A model of competing dipoles formation are suggested to describe the mechanism.

Using a combination of hysteresis loop, Kerr microscope, and x-ray magnetic circular dichroism measurements, we investigated the antiferromagnetic (AFM) domain switching process modulated by the sub-nm thick Co inserting layer in a single crystalline Fe/Co/CoO/MgO(001). The CoO AFM domain switching occurs at lower temperature for the thicker Co interlayer, and the activation energy barrier of CoO AFM domain switching decreases as the Co interlayer thickness increases. The exchange coupling strength between the AFM spins in CoO layer and the ferromagnetic spins in the Fe/Co bilayer is found to be independent of the Co layer thickness. Our results suggest an approach to modulate the dynamic properties of AFM domains with an interfacial modification.

Magnetoelectric coupling at room temperature in multiferroic materials, such as BiFeO3, is one of the leading candidates to develop low-power spintronics and emerging memory technologies. Although extensive research activity has been devoted recently to exploring the physical properties, especially focusing on ferroelectricity and antiferromagnetism in chemically modified BiFeO3, a concrete understanding of the magnetoelectric coupling is yet to be fulfilled. We have discovered that La substitutions at the Bi-site lead to a progressive increase in the degeneracy of the potential energy landscape of the BiFeO3 system exemplified by a rotation of the polar axis away from the 〈111〉pc towards the 〈112〉pc discretion. This is accompanied by corresponding rotation of the antiferromagnetic axis as well, thus maintaining the right-handed vectorial relationship between ferroelectric polarization, antiferromagnetic vector and the Dzyaloshinskii-Moriya vector. As a consequence, La-BiFeO3 films exhibit a magnetoelectric coupling that is distinctly different from the undoped BiFeO3 films., BiFeO3 has a wide application but the impact of rare-earth substitution for the evolution of the coupling mechanism is unknown. Here, the authors reveal the correlation between ferroelectricity, antiferromagnetism, a weak ferromagnetic moment, and their switching pathways in La-substituted BiFeO3.

Author(s): Yang, M; Li, Q; Hou, D; Shafer, P; N'diaye, AT; Klewe, C; Wang, TY; Zhang, X; Hwang, C; Qiu, ZQ | Abstract: Spin pumping from ferromagnetic Fe into antiferromagnetic CoO across a Ag spacer layer was studied using ferromagnetic resonance (FMR) in Py/CoO/Ag/Fe/Ag(001). The thin Py film on top of CoO permits an alignment of the CoO Neel vector through field cooling in two otherwise equivalent [110] and [110] crystalline axes which are parallel and perpendicular to the Fe magnetization direction, respectively. Fe FMR linewidth is measured as a function of Ag thickness in 10-20-GHz frequency range and in 180-330 K temperature range. We find that there exists an anisotropy in the Fe FMR damping for parallel and perpendicular alignment of the Fe and CoO spins. However, such anisotropic damping exists only at thin Ag thickness where there exists a magnetic interlayer coupling between Fe and CoO, and vanishes at thick Ag thickness where the interlayer coupling becomes negligible but permitting spin-current transmission into CoO. Our result indicates the absence of anisotropic spin current for parallel and perpendicular alignment of the Fe and CoO spin axes.

Spintronic elements based on spin transfer torque have emerged with potential for on-chip memory, but they suffer from large energy dissipation due to the large current densities required. In contrast, an electric-field-driven magneto-electric storage element can operate with capacitive displacement charge and potentially reach 1-10 µJ cm-2 switching operation. Here, magneto-electric switching of a magnetoresistive element is shown, operating at or below 200 mV, with a pathway to get down to 100 mV. A combination of phase detuning is utilized via isovalent La substitution and thickness scaling in multiferroic BiFeO3 to scale the switching energy density to ≈10 µJ cm-2 . This work provides a template to achieve attojoule-class nonvolatile memories.

Electrochemical N2 reduction (ENR) offers a promising route for NH3 production. To promote this kinetically sluggish process, the design and development of electrocatalysts with high performance, good durability, low cost, and earth abundance are highly demanded. Here, we report a facile approach for the synthesis of metal-doped ultrafine W18O49 nanowires with significantly enhanced capability for electrocatalytic N2 reduction to produce NH3 within a wide pH range. In particular, the Mo-doped W18O49 catalyst can reduce N2 to NH3 with a faradaic efficiency approaching 12.1% at −0.2 V (versus the reversible hydrogen electrode, vs. RHE) and an NH3 yield rate of 5.3 μgNH3 h–1 mgcat.–1 at −0.5 V (vs. RHE) in 0.1 M Na2SO4, which is about two times higher than that of pristine W18O49. We find occurrence of strong electron transfer from Mo to W, which facilitates N2 adsorption and activation, thus accelerating the ENR to generate NH3. This work provides a simple and effective method to modify metal oxides for efficient electrochemical N2 fixation.

Background The management of metastatic cancer remains a major challenge in cancer therapy worldwide. The targeted delivery of chemotherapeutic drugs through rationally designed formulations is one potential therapeutic option. Notably, excipient-free nanodispersions that are entirely composed of pharmaceutically active molecules have been evaluated as promising candidates for the next generation of drug formulations. Formulated from the self-assembly of drug molecules, these nanodispersions enable the safe and effective delivery of therapeutic drugs to local disease lesions. Here, we developed a novel and green approach for preparing nanoparticles via the self-assembly of rhein (RHE) and doxorubicin (DOX) molecules, named RHE/DOX nanoparticles (RD NPs); this assembly was associated with the interaction force and did not involve any organic solvents. Results According to molecular dynamics (MD) simulations, DOX molecules tend to assemble around RHE molecules through intermolecular forces. This intermolecular retention of DOX was further improved by the nanosizing effect of RD NPs. Compared to free DOX, RD NPs exerted a slightly stronger inhibitory effect on 4T1 cells in the scratch healing assay. As a dual drug-loaded nanoformulation, the efficacy of RD NPs against tumor cells in vitro was synergistically enhanced. Compared to free DOX, the combination of DOX and RHE in nanoparticles exerted a synergistic effect with a combination index (CI) value of 0.51 and showed a stronger ability to induce cell apoptosis. Furthermore, the RD NP treatment not only effectively suppressed primary tumor growth but also significantly inhibited tumor metastasis both in vitro and in vivo, with a better safety profile. Conclusions The generation of pure nanodrugs via a self-assembly approach might hold promise for the development of more efficient and novel excipient-free nanodispersions, particularly for two small molecular antitumor drugs that potentially exert synergistic antiproliferative effects on metastatic breast cancer.

The technique of x-ray detected ferromagnetic resonance (XFMR) represents an indispensable new tool in the investigation of spin current effects in complex heterostructures, as it enables the observation of magnetization and spin dynamics with element-, site-, and valence state-specificity. Here we give an overview of the development of XFMR and characterize different approaches to measure spin dynamics using synchrotron radiation. We provide a detailed description of the working principle of the technique and give an overview of recent work carried out at beamline 4.0.2 of the Advanced Light Source and beamline I10 of the Diamond Light Source using XFMR. Results from our latest publications demonstrate the capabilities and sensitivity of the technique. Element- and phase-resolution provide intriguing insights into the mechanisms of spin current propagation in multilayers, while the high sensitivity of XFMR allows for detection of even miniscule signals. Most recently, the utilization of linearly polarized x-rays for XFMR and the detection of XFMR by means of x-ray diffraction rather than x-ray absorption demonstrate two new capabilities in the investigation of spin dynamics.

In this study, Al2O3 ceramics parts were printed by inkjet printing technology with different printed paths distributions, such as the spiral printed path, round trip straight printed path and ladder lap printed path. The influences of inkjet printed paths on sintering performance and thermal shock resistance of the Al2O3 green bodies were investigated. The sintering performance of the green sample with the ladder lap printed path is the highest among the three samples. Sintered at 1550 ℃, its bulk density and porosity reached 3.73 g/cm3 and 10.80%, respectively. In addition, the thermal shock resistance of the sample with the step print path reached 11 times. The results suggest that the optimization of the printed path provides an effective way to print 3D ceramics with good performances through 3D inkjet-printing technology.

Magnetic van der Waals (vdW) materials have emerged as promising candidates for spintronics applications, especially after the recent discovery of intrinsic ferromagnetism in monolayer vdW materials. There has been a critical need for tunable ferromagnetic vdW materials beyond room temperature. Here, we report a real-space imaging study of itinerant ferromagnet Fe3GeTe2 and the enhancement of its Curie temperature well above ambient temperature. We find that the magnetic long-range order in Fe3GeTe2 is characterized by an unconventional out-of-plane stripe-domain phase. In Fe3GeTe2 microstructures patterned by a focused ion beam, the out-of-plane stripe domain phase undergoes a surprising transition at 230 K to an in-plane vortex phase that persists beyond room temperature. The discovery of tunable ferromagnetism in Fe3GeTe2 materials opens up vast opportunities for utilizing vdW magnets in room-temperature spintronics devices.

Using X-ray Magnetic Linear Dichroism (XMLD) measurement, we investigate the antiferromagnetic (AFM) NiO spin reorientation transition (SRT) in epitaxial NiO/CoO/MgO(0 0 1) system at room temperature and constructed a complete NiO spin phase diagram. Then utilizing Magneto-Optic Kerr Effect (MOKE) combined with a rotation magnetic field (ROTMOKE), we investigated the effect of NiO SRT on the magnetic anisotropy of a ferromagnetic (FM) Py overlayer in Py/NiO/CoO/MgO(0 0 1) system. We find that the Py coercivity and anisotropy only slightly enhanced for Py on top of out-of-plane NiO spins but greatly enhanced for Py on top of in-plane NiO spins. Both the uniaxial and fourfold anisotropies of the Py showed a clear dependence on the NiO spin orientation.

Inspired by bird's nest structure, fibrous mullite ceramic was fabricated by vacuum impregnation with mullite fibers as raw material and zirconia sol-gel as inorganic binder. The effect of impregnation times on the properties of the fibrous mullite ceramic, such as porosity, microstructure, compressive strength and room-temperature thermal conductivity were investigated. The results showed that low density (0.45–0.66 g/cm 3 ), relative high compressive strength (0.62–3.34 MPa) and low thermal conductivity (0.037–0.125 W/mk) were exhibited for the sample. The toughness of fibrous mullite ceramic was enhanced due to the micro-creaks caused by transformation of zirconia. From the experimental results, it is suggested that it was an optimal method which have the potential use in high-temperature thermal insulation materials to produce fibrous mullite ceramics.

Mesoporous hydroxyapatite is widely applied in biomedical and environmental fields due to its high surface area and adsorption capacity. In current work a one-step hydrothermal method to synthesize mesoporous HA was developed with the assistance of a cost-effective template vitamin C. It was observed the pore size and morphology of hydrothermally synthesized HA were correlated to applied solution composition. A combination of calcium hydroxide, orthophosphate, and vitamin C can finally result in mesoporous rod-like HA nanoparticles with surface area of 88 m2.g−1 and pore size of 15.7 nm on average. The mesoporous HA exhibited enhanced adsorption of model drug doxorubicin in comparison to conventionally synthesized HA as expected. Consequently, this work provides new pathway to prepare mesoporous HA with advantages of economy and convenience.

We report the fabrication of epoxy-based composites using well-designed core/shell Si/SiO2 (denoted as Si*) and core/shell/shell structured Si/SiO2/Polydopamine (denoted as Si*@PDA) particles as fillers, which exhibit improved dielectric properties and thermal conductivity. Using the core-shell Si* and Si*@PDA particles as fillers in the epoxy-based composites, the dielectric loss tangent is remarkably suppressed and the volume resistivity is apparently enhanced, as compared with that using raw Si particles as fillers. Moreover, the Si*@PDA composites have higher dielectric constant and lower loss tangent. For instance, the dielectric constant of Si*@PDA/epoxy composite with 33.8 vol% filler content is up to 19.8 at room temperature at 100 Hz, which is nearly 5.3 times of that of the pure epoxy polymer (3.4), while its loss tangent is only 0.085. Additionally, the core-shell particle-based composites still possess a high thermal conductivity.

A 3D multi-time scale discrete element method-computational fluid dynamic (DEM-CFD) coupling approach was applied to investigate the filtration of micron-sized particles by different types of fiber arrays. Both the pressure drop and the filtration efficiency were examined to indicate the filtration performance of the fiber arrays. Fibers that were uniformly arrayed in a parallel or staggered manner were compared. Results showed that the staggered array showed a better performance than the parallel array in terms of both pressure drop and filtration efficiency. Further, we compared the performance of different staggered arrays, i.e. a regular case, one densified in the front layers and another densified in the back layers. The front densified array was found to enter the clogging and cake filtration stage in the shortest time, leading to the highest filtration efficiency, but the highest pressure drop. The back densified array still achieved a much higher filtration efficiency, despite a much lower pressure drop comparable to that of the regular array. The results suggest that the two kinds of densified arrays may be suited for different purposes, e.g. baghouse filters or breathing masks.

The increasing use of cerium dioxide nanoparticles (CeO2 NPs) has raised concerns about their potential environmental toxicity. Denitrifying phosphorus removal-aerobic granular sludge (DPR-AGS) is a distinct form of microbial aggregates. In this study, the phosphorus removal efficiencies, the metabolic intermediates of polyhydroxyalkanoates (PHA) and glycogen, the enzyme activities of exophosphatase (PPX) and polyphosphate kinase (PPK), and the microbial community of DPR-AGS under long-term exposure to CeO2 NPs (0 (the control), 1, and 10 mg L−1) in anaerobic/oxic/anoxic (A/O/A) sequencing batch reactors (SBRs) were investigated. The results showed that chronic toxicity caused by 10 mg L−1 CeO2 NPs resulted in increased reactive oxygen species (ROS) production and lactate dehydrogenase (LDH) release, which reached 176.32% and 237.35%, respectively, when compared with the control (100%). High-throughput sequencing showed that denitrifying-phosphorus-accumulating organisms (DPAOs) were more sensitive to CeO2 NPs than phosphorus-accumulating organisms (PAOs), which was in accordance with phosphorus transformations during one cycle. However, the abundance of Dechloromonas and Defluviicoccus increased from 4.68% and 3.08% (R0) to 9.95% and 7.06% (R10), respectively, indicating that the tolerance of glycogen-accumulating organisms to CeO2 NPs was stronger than that of PAOs, which was consistent with the transformation of the metabolic pathway from polyphosphate accumulation (PAM) to glycogen accumulation (GAM).

In order to investigate the effect of temperature on the microstructure evolution and mechanical response in the transverse direction of a wrought AZ31 (AZ31-TD) alloy under a high strain rate, the dynamic compression was conducted using Split Hopkinson Pressure Bar (SHPB) apparatus and a resistance-heated furnace under 1000 s−1 at 20–250 °C. By combining optical and EBSD observations, the microstructure’s evolution was specifically analyzed. With the help of theoretically calculated Schmid Factors (SF) and Critical Resolved Shear Stress (CRSS), the activation and development deformation mechanisms are systematically discussed in the current study. The results demonstrated that the stress–strain curves are converted from a sigmoidal curve to a concave-down curve, which is caused by the preferentially and main deformation mechanism {101¯2} tension twinning gradually converting to simultaneously exist with the deformation mechanism of a non-basal slip at an elevated temperature, then completing with each other. Finally, the dynamic recrystallization (DRX) and non-basal slip are largely activated and enhanced by temperature elevated to weaken the {101¯2} tension twinning.

Hydroxyapatite (HA) is a well-known material for biomedical applications and its performance depends greatly on its morphological features. Therefore, preparation of mesoporous HA with high surface area and adsorption capacity is highly deserved. In this research, a hydrothermal approach to synthesize mesoporous HA without post-processing calcination step is presented. The possibility using different polyphenols to generate mesoporous HA as well as using different phosphate sources to tailor the morphological features of HA is investigated. The as-prepared mesoporous HA particles are characterized by XRD, FTIR, SEM, TEM, BET, and zeta potential. Besides, the impacts of HA morphological features on model drug Dox are also studied. It is expected the strong interaction between –OH of polyphenols and Ca2+ makes polyphenols molecules occupy the inner sites of growing HA particles. After the removal of polyphenols by hydrothermal treatment and ethanol extraction, the occupied sites are transformed into mesopores. The typical mesoporous HA generated in present work has a rod-like morphology with BET specific surface area of 106.6 m2/g and an average pore size of 14.4 nm.

High-quality (0 1 0) VO2 thin films were epitaxially grown on functional ferroelectric (1 1 1)-oriented Pb(Mg1/3Nb2/3)0.7Ti0.3O3 (PMN-0.3PT) substrates by reactive magnetron sputtering. The VO2/PMN-0.3PT heterostructures demonstrated metal–insulator transition (MIT) hysteresis with a resistance change of the order of ∼350. Structural characterization of the heterostructures at varying temperatures confirmed that a structural phase transition accompanies the MIT. Moreover, the dynamic strain induced by the converse piezoelectric effect lowers the critical temperature of the MIT from 341.9 K at 0 kV/cm to 339.1 K at 6 kV/cm in the VO2/PMN-0.3PT heterostructures. The resistance of the VO2 thin films could be dynamically modulated by electric field-induced strain, with a change ratio of up to 9.8% near the ferroelectric coercive field. Moreover, the heterostructures displayed non-volatile resistance switching, providing the potential to encode binary information at room temperature by proper electric-field cycling. These functional heterostructures based on correlated electron materials may realize dynamic and non-volatile manipulation of the MIT and resistance switching, thus demonstrating great potential for use in energy-efficient and non-volatile oxide electronic devices.

Lead-free 0.912Ba0.97TiO3–0.088(Bi0.5Na0.5)TiO3–xTa2O5 (0 ≤ x ≤ 0.005) ceramics with positive temperature coefficient of resistivity (PTCR) were prepared by solid reaction sintering of high-purity metal oxides and carbonates reagents. The doping effect of Ta5+ ions on the microstructure and electrical properties of the samples was investigated. X-ray diffraction analysis indicated that all the samples were of a single tetragonal perovskite structure with the calculated c/a value first increased and then decreased with increasing x. The Raman shift at 305 cm−1 became strong firstly and then declined, and the broad band at 722 cm−1 narrowed initially and then broadened with the increase in Ta5+ content. The Curie temperature raised first and then decreased, presenting the highest value up to 170 °C for the samples with x = 0.001. Moreover, after the incorporation of Ta5+ ions, the PTCR (defined by the resistivity jump with the ratio of maximum to minimum ones) decreased first and then increased, presenting the best PTCR performance for the samples with x = 0.005. And with increasing x, the room temperature resistivity decreased first and then increased, displaying the lowest room temperature resistivity for the samples with x = 0.003.

The aerosol chemical vapor deposition (ACVD) process has been demonstrated as a promising approach to the single step synthesis of nanostructured metal oxide thin films. Multiple process parameters control the nanostructure morphology and the growth of thin films. This work focuses on utilizing a simulation based approach to understand the role of these parameters in governing the morphology of the thin film. A finite element based computational fluid dynamics model, coupled with a discrete-sectional aerosol model, and a boundary layer diffusion and sintering model has been formulated to predict the evolution of particle size distribution and the morphology of the synthesized nanostructured film. The morphology predicted by the model was validated by experimental observations. The model enables scale up and wider application of the ACVD process and can be extended to other gas phase deposition systems.

Development of polymer-based composites with simultaneously high thermal conductivity and breakdown strength has attracted considerable attentions owing to their important applications in both electronic and electric industries. In this study, we successfully design novel epoxy-based composites with nano-Al2O3/epoxy composite layer sandwiched between micro-Al2O3/epoxy composite layers, which show synergistically and significantly enhanced thermal conductivity and breakdown strength. Compared with the traditional composites, the bottleneck that both thermal conductivity and breakdown strength cannot be simultaneously enhanced can be overcome successfully. An optimized sandwiched alumina–epoxy composite with 70 wt% micro-Al2O3 fillers in the outer layers and 3 wt% nano-Al2O3 in the middle layer simultaneously displays a high thermal conductivity of 0.447 W m−1 K−1 (2.4 times of that of epoxy) and a high breakdown strength of 68.50 kV mm−1, which is 6.3 % higher than that of neat epoxy (64.45 kV mm−1). The experimental results on the thermal conductivity of multi-layered alumina–epoxy composites were in well accordance with the theoretical values predicted from the series conduction model. This novel technique simultaneously improves thermal conductivity and breakdown strength, which is of critical importance for design of perspective composites for electronic and electric equipments.

Merons which are topologically equivalent to one-half of skyrmions can exist only in pairs or groups in two-dimensional (2D) ferromagnetic (FM) systems. The recent discovery of meron lattice in chiral magnet Co8Zn9Mn3 raises the immediate challenging question that whether a single meron pair, which is the most fundamental topological structure in any 2D meron systems, can be created and stabilized in a continuous FM film? Utilizing winding number conservation, we develop a new method to create and stabilize a single pair of merons in a continuous Py film by local vortex imprinting from a Co disk. By observing the created meron pair directly within a magnetic field, we determine its topological structure unambiguously and explore the topological effect in its creation and annihilation processes. Our work opens a pathway towards developing and controlling topological structures in general magnetic systems without the restriction of perpendicular anisotropy and Dzyaloshinskii–Moriya interaction., A meron is one half of a skyrmion but whether a single meron pair can be created and stabilized remains a challenging question. Here, Gao et al. develop a method to create and stabilize individual pairs of merons in a continuous Py film by local vortex imprinting from Co disks.

Author(s): Li, Q; Yang, M; N'Diaye, AT; Klewe, C; Shafer, P; Gao, N; Wang, TY; Arenholz, E; Zhang, X; Hwang, C; Li, J; Qiu, ZQ | Abstract: An antiferromagnetic NiO spiral wall in Fe/NiO/Co0.5Ni0.5O/vicinal Ag(001) was created by rotating Fe magnetization and investigated using x-ray magnetic linear dichroism (XMLD). Different from the Mauri's 180° spiral wall, we find that the NiO spiral wall always switches its chirality at ∼90 rotation of the Fe magnetization, and unwinds the spiral wall back to a single domain with a further rotation of the Fe magnetization from 90° to 180°. The effect of this chirality switching on the magnetic anisotropy was studied using rotational magneto-optic Kerr effect (ROTMOKE) on Py/NiO/Co0.5Ni0.5O/vicinal Ag(001). We find that the original Mauri's model has to be corrected by an energy folding due to the chirality switching, which consequently converts the exchange bias from the Mauri's 180° spiral wall into a uniaxial anisotropy and a negative fourfold anisotropy.

The recent discovery of spin current transmission through antiferromagnetic insulating materials opens up vast opportunities for fundamental physics and spintronics applications. The question currently surrounding this topic is: whether and how could THz antiferromagnetic magnons mediate a GHz spin current? This mismatch of frequencies becomes particularly critical for the case of coherent ac spin current, raising the fundamental question of whether a GHz ac spin current can ever keep its coherence inside an antiferromagnetic insulator and so drive the spin precession of another ferromagnet layer coherently? Utilizing element- and time-resolved x-ray pump-probe measurements on Py/Ag/CoO/Ag/Fe75Co25/MgO(001) heterostructures, here we demonstrate that a coherent GHz ac spin current pumped by the Py ferromagnetic resonance can transmit coherently across an antiferromagnetic CoO insulating layer to drive a coherent spin precession of the Fe75Co25 layer. Further measurement results favor thermal magnons rather than evanescent spin waves as the mediator of the coherent ac spin current in CoO., The mechanism underpinning the frequency mismatch between THz magnons and the GHz spin currents observed in antiferromagnetic insulators remains unknown. Here, the authors demonstrate that, in a Py/Ag/CoO/Ag/Fe75Co25/MgO(001) heterostructure, a GHz spin current transmits coherently across the antiferromagnetic CoO insulating layer to drive a coherent spin precession of the ferromagnetic Fe75Co25 layer.

In this paper, we prepare heavily electron doped $\mathrm{L}{\mathrm{a}}_{0.04}\mathrm{B}{\mathrm{a}}_{0.96}\mathrm{Sn}{\mathrm{O}}_{3}$ (LBSO) thin films on a $\mathrm{SrTi}{\mathrm{O}}_{3}$ (STO) substrate by the pulsed laser deposition method under different oxygen pressures, in which different levels of oxygen vacancy concentrations are present. Normally, oxygen vacancies are implicitly assumed as isolated point defects that dope the materials with electron carriers, whereas oxygen-deficient LBSO films exhibit an apparent metal-to-insulator transition combined with lower carrier concentrations and mobility with increased oxygen vacancies, which are concluded from the transport measurement data. Considering the almost constant density of threading dislocations and the higher formation energies for other intrinsic crystal defects, the observed transport trends are ascribed to the extra oxygen vacancies introduced. Therefore, strong electron localization originating from the interaction between the oxygen vacancy and La impurity is proposed for interpreting the behavior in oxygen-deficient LBSO films. Oxygen-deficient crystal structure models for LBSO have been optimized and the electronic structures are revealed by first-principles calculations based on the density functional theory. The partial density of states results indicate that strong electron localization comes from the deep strongly localized states in the forbidden gap, which are mainly composed of hybridized orbitals of $\mathrm{O}\phantom{\rule{0.16em}{0ex}}2p$ with $\mathrm{Sn}\phantom{\rule{0.16em}{0ex}}5s5p$ and some amount of $\mathrm{Sn}\phantom{\rule{0.16em}{0ex}}4d$. Thus, the control of the oxygen defects and the related electronic states in barium stannate is essential for achieving optimal electrical performance and as potential applications in perovskite heterostructure devices.

Due to the increased use of cerium oxide nanoparticles (CeO2 NPs), their potential environmental risks have caused concern. However, their effects on the aerobic granular sludge (AGS) process and the later recovery of AGS are still unclear. In this study, we comprehensively determined the changes in pollutant removal and the levels of extracellular polymeric substances (EPS) in AGS that were exposed to CeO2 NP treatments (0 (the control, R0), 1 (R1), and 5 (R5) mg/L), following an increase in the influent chemical oxygen demand (COD). An increase in the CeO2 NP concentration enhanced their inhibitory effect on the removal of total nitrogen (TN) and total phosphorus (TP), and promoted the production of polysaccharides (PS) and proteins (PN) in loosely bound EPS (LB-EPS) or tightly bound EPS (TB-EPS), as well as the dissolved organic carbon (DOC) components in EPS, but had no long-term effects on the removal of organic matter. When the addition of CeO2 NPs was stopped and the concentration of influent COD increased, the TN and TP removal efficiencies in R1 and R5 slowly increased and recovered. In R1, they were only 4.55 &plusmn, 0.55% and 2.71 &plusmn, 0.58% lower than in R0, respectively, while the corresponding values for R5 were 5.06 &plusmn, 0.46% and 6.20 &plusmn, 0.63%. Despite the LB-EPS and TB-EPS concentrations in the R1 and R5 treatments recovering and being similar to the levels in the control when no CeO2 NPs were added, they were still slightly higher than in the R0, which indicating that the negative effects of CeO2 NPs could not be completely eliminated due to the residual CeO2 NP levels in AGS.

Colon adenocarcinoma is the third most common cause of cancer-related deaths worldwide owing to its aggressive nature. Here, we developed a novel oral drug delivery system (DDS) that comprised active targeted nanoparticles made from gelatin and chitosan (non-toxic polymers). The nanoparticles were fabricated using a complex coacervation method, which was accompanied by conjugation of wheat germ agglutinin (WGA) onto their surface by glutaraldehyde cross-linking. Specifically, we integrated 5-fluorouracil (5-FU), the first-line treatment agent against colon cancer, and (-)-epigallocatechin-3-gallate (EGCG), which inhibits tumor growth via anti-angiogenesis and apoptosis-inducing effects, into the nanoparticles, named WGA-EF-NP. The 5-FU and EGCG co-loaded nanoparticles showed sustained drug release, enhanced cellular uptake, and longer circulation time. WGA-EF-NP exhibited superior anti-tumor activity and pro-apoptotic efficacy compared to the drugs and nanoparticles without WGA decoration owing to better bioavailability and longer circulation time in vivo. Thus, WGA-EF-NP shows promise as a DDS for enhanced efficacy against colon cancer.

We have studied the impact of lattice geometry on the dynamic properties of close-spaced arrays of circular nanomagnets, also known as magnonic crystals. To this end, we prepared 2D nanomagnet arrays with both square and hexagonal lattice symmetries (300-nm disk diameter, 400-nm center-to-center distance) and performed broadband ferromagnetic resonance (FMR) measurements. Micromagnetic simulations were used to interpret distinct features of the measured resonance spectra. The FMR bias field was applied along two distinct principal directions for each lattice, and a sample with well-separated, decoupled disks was measured for reference. We found that the interdisk dipolar coupling has a strong impact on the FMR for these 2D magnonic crystals. Distinctly different oscillation modes were found for the individual nanomagnets, dependent on lattice symmetry and direction of the bias field. Moreover, we find that spectral peak splitting from excitation of edge and center modes, as well as the damping, depends on the lattice symmetry and the orientation of the bias field. These findings demonstrate that lattice geometry has a strong influence on the excited spin-wave spectrum and is a relevant design parameter for spintronic devices. © American Physical Society 2019. This is the authors accepted and refereed manuscript to the article.

Low silicon oxide (SiO) is a promising anode material for lithium and potassium ion batteries due to its high theoretical capacity (~2400 mAh g−1) and good cycle performance. However, volume effects and poor intrinsic electronic conductivity during cycling limit its practical application. To meet this challenge, we synthesized SiOx@C (SC) anodes with various carbon contents by ball milling and high-temperature carbonization. The graphite/asphalt coating reduces the volume expansion of SiO and reduces the mechanical stress. When used as a lithium ion battery (LIB) electrode, the SC-2 material retained a lithium storage capacity of 729.5 mAh g−1 after 200 cycles at a current density of 200 mA g−1. In addition, when used as a potassium ion battery (KIB) electrode, the SC-2 material provides a high capacity with a discharge capacity of 107.0 mAh g−1 after 400 cycles at 200 mAh g−1 and excellent cycle life (after 2000 cycles at 500 mA g−1, the capacity 80.8 mAh g−1 was retained). The potassium storage mechanism of the SC electrode was analyzed by the simple ex-situ XRD technique. These results show that SC anodes are promising for application as anode materials for LIBs and KIBs.

The volume changes of Bi2O3 and Bi, which have a high theoretical gravimetric ca-pacity and high volumetric capacity, during alloying is the main challenge in the fabri-cation of high-performance Bi-based electrodes. In the present study, a simple chemical blowing method is adopted to embed Bi2O3 and Bi nanoparticles generated by thermal decomposition and reduction in an N-doped honeycomb-like porous carbon matrix (Bi2O3/Bi@NHPC). In charge/discharge processes, the honeycomb-like porous carbon matrix effectively prevents the Bi2O3 and Bi nanoparticles from pulverization triggered by volume changes and provides abundant channels for fast electron and Li-ion diffusion. When utilized for lithium storage, the electrode exhibits a high reversible specific capacity of 408 mAh g−1 after 1000 cycles at 1 A g−1. Remarkably, it presents a superior rate capability of 258 mAh g −1 at 10 A g−1 and a decent cycle retention of 78 % at 5 A g−1 after 2000 cycles. The qualitative analysis results reveal that the excellent rate performance and rapid reaction kinetics of the as-prepared electrode are mainly derived from the high capacitive contribution induced by the honeycomb-like porous carbon matrix. The reported results demonstrate that Bi2O3/Bi@NHPC, which has a convenient preparation method, is a potential anode material for lithium-ion batteries.

The mixed dimensional materials, especially 0D/2D mixed materials have been regarded as outstanding candidates for photodetector and photovoltaic devices, while have rarely been utilized for photocatalytic reactions including photosynthesis, water splitting and CO2 reduction. In this work, a mixed dimensional material composited by cubic 0D CsPbBr3 perovskite quantum dots (PQDs) and cubic 2D-PbS is prepared for reduction of CO2 to fuels. The PQDs, as light-harvesting components, are homogeneously grown on the 2D-PbS nano-substrate which is employed for electron transport. The same cubic crystal structures and rather small lattice mismatch ( Δ d / d CsPbBr 3 = 0.84 % ) between CsPbBr3 and PbS guarantee easy in-situ growth of PQDs on PbS nano-substrate and rapid electron migration. As a result, an improved photocurrent is obtained based on the combination of the advantages of 0D and 2D materials. In addition, the size of PQDs synthesized on the 2D-PbS is dramatically reduced in comparison to that synthesized in solvent, thus endowing them wider bandgap and greater potential enough for the photocatalytic reactions. This PQDs/2D-PbS mixed dimensional materials exhibit outstanding selectivity (over 99%) and activity (yield 81.6 and 52.7 μmol g−1) for reducing CO2 to CO and CH4, from which the CH4 yielded is ca. 9-fold than that of pure PQDs.

In present work condensed phosphates (P2O74 − and P3O105 −) were used as phosphate source in induction heating to deposit calcium phosphate coatings. The phase, morphology, and composition of different phosphate-related coatings were characterized and compared using XRD, FTIR, and SEM analyses. Results showed that P2O74 − formed calcium pyrophosphate hydrate coatings with interconnected cuboid-like particles. The as-deposited calcium tripolyphosphate hydrate coating with P3O105 − was mainly composed of flower-like particles assembled by plate-like crystals. The bioactivity and cytocompatibility of the coatings were also studied. Moreover, the feasibility of using hybrid phosphate sources for preparing and depositing coatings onto magnesium alloy was investigated.

Chinese mystery snail is a popular aquatic food in China, resulting in tonnes of shells as waste every year. In present work, these shells were recycled as calcium source to prepare HA. Initially, shells were found to decompose within 860 °C to porous CaO. The calcined shells were then hydrothermally utilized to synthesize HA with the help of different phosphate sources (PO 4 3− , P 2 O 7 4− , P 3 O 10 5− , and P 6 O 18 6− ). Under hydrothermal processing, condensed phosphate ions could be hydrolyzed into PO 4 3− to react with Ca 2+ . The prepared HA was subsequently characterized by XRD, FTIR, SEM, EDX and TEM. It was found condensed phosphates could result in significant changes to the morphology of HA in comparison to orthophosphate. In particular, P 6 O 18 6− related HA appeared to be mesoporous. The cytocompatibility of different phosphate source related HA was also investigated.

Lead-free 0.912Ba 0.97 TiO 3 -0.088(Bi 0.5 M 0.5 )TiO 3 (M=Li, Na, K, Rb) ceramics with positive temperature coefficient of resistivity (PTCR) were prepared by conventional solid sintering reaction using high-purity reagents of metal oxides and carbonates. The effect of (Bi 0.5 M 0.5 )TiO 3 (M=Li, Na, K, Rb) doping on the microstructure and electrical properties of the samples were investigated. X-ray diffraction analysis indicated that all the samples were of a single perovskite structure with tetragonal phase, and the calculated c/a value increased first and then decreased. The Raman shift at 305 cm −1 became strong first and then declined when M in the dopant (Bi 0.5 M 0.5 )TiO 3 was changed from Li to Rb. The Curie temperature of the samples displayed a tendency to increase first and then decrease, in which BaTiO 3 -(Bi 0.5 K 0.5 )TiO 3 ceramics presented the highest value. Moreover, after the incorporation of alkali ions, the PTCR value (defined by the resistivity jump with the ratio of the maximum to minimum) and room temperature resistivity of the samples decreased first and then increased, in which BaTiO 3 -(Bi 0.5 Na 0.5 )TiO 3 ceramics possessed the lowest room temperature resistivity.