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AlN ceramics were prepared by plasma activation sintering (PAS) with compound additives yttrium acetylacetonate (Y(acac)3) and melamine (C3H6N6). The effects of compound additives on the microstructure, density, and thermal properties of AlN ceramic were studied. Y(acac)3 and C3H6N6 can form Y2O3, residual organic carbon and reducing gas during the heating process, which improves the AlN sintering performance at a temperature of 1 700 °C and the bulk thermal conductivity. When the content of Y(acac)3 is 10 wt% and C3H6N6 is 3 wt%, the thermal conductivity of AlN ceramics is 105.6 W/(m·K), which is much higher than that of AlN ceramics with Y2O3 under the same sintering conditions. This work provides theoretical reference for the preparation of high-performance AlN ceramic. [ABSTRACT FROM AUTHOR]

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) powders were rapidly synthesized by microwave assisted sol–gel-hydrothermal method (MSGH) at low temperature. The effects of synthesis temperature on the structure and sintering properties of the obtained BCZT powders were investigated. The results showed that the appropriate synthesis temperature synthesized by MSGH can be reduced to 180 °C. At this synthesis temperature, BCZT powder exhibits a pure phase structure, good microscopic morphology, and accurate elemental proportions, with an average particle size of about 85 nm. The sintered BCZT ceramics exhibited excellent electrical properties (εmax = 9586, 2Pr = 26.36 µC/cm2, d33 = 526 pC/N), suggesting favorable sintering characteristics of BCZT powders synthesized by MSGH. [ABSTRACT FROM AUTHOR]

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ferroelectric epitaxial films deposited at different oxygen partial pressure were successfully obtained by pulsed laser deposition. The effects of oxygen partial pressure on the phase structure, microstructure, electrical properties and leakage mechanism were studied. The results showed that the BCZT epitaxial films have a smooth surface, uniform thickness, well integrated with substrate and no elemental segregation. BCZT epitaxial film with oxygen partial pressure of 15 Pa exhibited the optimal electrical properties (2Pr–22.48 µC/cm2, Jleak ∼ 1.42 × 10−3 A/cm2). The results of conduction mechanism fitting indicated that BCZT film conductivity mechanism followed the Ohmic mechanism at low electric fields, while it followed the Fowler–Nordheim tunneling mechanism at high electric fields. [ABSTRACT FROM AUTHOR]

In the present work, Fe-Mn-Al-C powder mixtures were manufactured by elemental powders with different ball milling time, and the porous high-Mn and high-Al steel was fabricated by powder sintering. The results indicated that the powder size significantly decreased, and the morphology of the Fe powder tended to be increasingly flat as the milling time increased. However, the prolonged milling duration had limited impact on the phase transition of the powder mixture. The main phases of all the samples sintered at 640°C were α-Fe, α-Mn and Al, and a small amount of Fe2Al5 and Al8Mn5. When the sintering temperature increased to 1200°C, the phase composition was mainly comprised of γ-Fe and α-Fe. The weight loss fraction of the sintered sample decreased with milling time, i.e., 8.3wt% after 20 h milling compared to 15.3wt% for 10 h. The Mn depletion region (MDR) for the 10, 15, and 20 h milled samples was about 780, 600, and 370 µm, respectively. The total porosity of samples sintered at 640°C decreased from ∼46.6vol% for the 10 h milled powder to ∼44.2vol% for 20 h milled powder. After sintering at 1200°C, the total porosity of sintered samples prepared by 10 and 20 h milled powder was ∼58.3vol% and ∼51.3vol%, respectively. The compressive strength and ductility of the 1200°C sintered porous steel increased as the milling time increased. [ABSTRACT FROM AUTHOR]

The piezoelectric strain of K0.5Na0.5NbO3-based lead-free ceramic at different temperatures was studied. The Rayleigh analysis shows that the intrinsic and extrinsic contributions are increased at temperature from 173 to 298 K. In addition, a monoclinic phase structure was observed at 83 K. The results of phase field simulation show that the temperature dependent microstructure evolution is a function of the local structure size. This work contributes to understanding the structure and properties relationship of the multi-cations doped KNN-based piezoelectric ceramics as a function of temperature. [ABSTRACT FROM AUTHOR]

Ba0.85Ca0.15Zr0.1Ti0.9O3/La0.7Sr0.3MnO3 (BCZT/LSMO) bilayer multiferroic heterostructures with different BCZT layer thickness are fabricated by pulsed laser deposition technique. Structural characterization of XRD and TEM reveals the epitaxial growth of the bilayer heterostructures, whose residual strain reduces with increasing thickness. The room temperature multiferroic characteristics of the bilayer heterostructures are demonstrated by the simultaneously observed ferroelectric and ferromagnetic properties as well as the magnetoelectric effect. Due to the varying residual strain, the multiferroic properties of the bilayer heterostructures show strong dependence on the BCZT layer thickness, which significantly improves with increasing thickness. The largest magnetoelectric coefficient with αE31 value of 355.2 mV/cm·Oe is achieved in BCZT/LSMO bilayer heterostructures with BCZT layer thickness of 150 nm. [ABSTRACT FROM AUTHOR]

Vanadium films were deposited on Si(100) substrates at room temperature by direct current (DC) magnetron sputtering. The microstructure and surface morphology were studied using scanning electron microscopy (SEM) and atomic force microscope (AFM). The oxidation resistance of films in air was studied using X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The results showed that the amorphous vanadium film with a flatter surface had higher oxidation resistance than the crystalline film when exposed to atmosphere. The rapid formation of the thin oxide layer of amorphous vanadium film could protect the film from sustained oxidation, and the relative reasons were discussed. [ABSTRACT FROM AUTHOR]

BaTi5O11 nanocrystals were synthesized by a hydrothermal method. The influence of Ba/Ti molar ratio in the Ba–Ti precursors on the morphology and dielectric properties of BaTi5O11 nanocrystals was investigated. In the precursors, the Ba2+ ion concentration was decreased from 0.02 to 0.01 mol/L, and the Ti4+ ion concentration was increased from 0.08 to 0.09 mol/L. The rice-like BaTi5O11 nanocrystals were synthesized at Ba/Ti molar ratios of 20:80 and 18:82, while the flower-like BaTi5O11 nanocrystals were formed at Ba/Ti molar ratios of 15:85, 12:88 and 10:90. The pure BaTi5O11 phase was synthesized at Ba/Ti molar ratio of 18:82 in the precursor, and the material had the permittivity of 38.9 at 8 GHz, which was close to that of the bulk BaTi5O11 ceramics. [ABSTRACT FROM AUTHOR]

Lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) powders were successfully synthesized by sol–gel-hydrothermal method. The effect of NaOH concentration on microstructure and phase composition of BCZT powders was studied. The results of XRD, SEM, TEM, FTIR, and EDS showed that the synthesis temperature of BCZT powders could be decreased to a low temperature of 180 °C, which was about 1150 °C lower when compared with solid-state reaction and 800 °C lower when compared with sol–gel methods respectively. The NaOH concentration exerted a great effect on the structure of BCZT powders, as well as the average particle size. When the NaOH concentration was 8 M, BCZT powders had a cubic phase perovskite structure with a homogeneous composition, and the average particle size was about 60 nm. The BCZT ceramics followed by sintering had dense structure and excellent electrical properties (2Pr = 24.62 μC/cm2, 2Ec = 3.24 kV/cm, d33 = 488 pC/N). The significant properties could be attributed to the high activity of powders synthesized by sol–gel-hydrothermal method. The present study may provide a new method for low-temperature synthesis of lead-free piezoelectric powders with fine phase, microscopic morphology, and high activity. Highlights: Well-crystallized BCZT powders were successfully synthesized by sol–gel-hydrothermal method. The synthesis temperature was decreased to a low temperature of 180 °C. Effects of alkaline solution concentration on structure of sol–gel-hydrothermal derived BCZT powders were analyzed and the formation mechanism was discussed. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass-derived bio-oil is considered as a promising renewable biofuel. In this paper, incipient wetness impregnation method, ammonia grafting method and direct synthesis method were employed as nickel loading methods for the preparation of Ni/Al-SBA-15 catalysts. The effects of these nickel loading approaches on the structure and hydrodeoxygenation performance of Ni/Al-SBA-15 were studied. The structure of Ni/Al-SBA-15 was significantly influenced by the nickel loading methods, including the specific surface area, the pore volume, the wall thickness and so on. Nickel loading methods also affected the actual nickel content of nickel-based catalysts. Unsuccessful loading of nickel species was observed during the preparation of Ni/Al-SBA-15 using direct synthesis method. The conversion of eugenol and selectivity of products after hydrodeoxygenation in n-dodecane over Ni/Al-SBA-15 catalysts were investigated. Results showed that the conversion of eugenol nearly reached 100% for all the reaction, but the composition of product was significantly different when using different Ni/Al-SBA-15 as hydrodeoxygenation catalyst. The reaction pathway of eugenol hydrodeoxygenation in n-dodecane was also speculated in this paper. Effects of nickel loading approaches on the structure and hydrodeoxygenation performance of Ni/Al-SBA-15 were investigated. For the liquid phase hydrodeoxygenation of eugenol to hydrocarbon, catalysts prepared by ammonia grafting method exhibited the highest catalytic activity. [ABSTRACT FROM AUTHOR]

A novel method, sol–gel-hydrothermal process, was employed to prepare Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) powders at a rather lower temperature of 180 °C. The effects of synthesis time on the structure, morphology and size distribution of the powders were studied by the means of XRD, SEM and FTIR. BCZT powders could be obtained at a suitable synthesis time of 12 h, which were well-crystallized and compositional uniform with an average particle size of 93 nm. BCZT ceramics sintered from the synthesized powders had a dense microstructure with a density of 5.59 g/cm3 (> 95%) and excellent properties (2Pr = 25.12 μC/cm2, 2Ec = 4.31 kV/cm, d33 = 492pC/N, εr = 9173), indicating the high activity of the BCZT powders by sol–gel-hydrothermal process. [ABSTRACT FROM AUTHOR]

Pseudorabies (PR) has been prevalent in Chinese swine breeding farms since the outbreak at the end of 2011. For investigating current prevalence of PR, a nationwide surveillance has been performed in this study. The swine serum samples were collected from 93, 100, 92, and 91 swine farms in China during 2013-2016, respectively. Since the extensive use of gE-deleted pseudorabies virus (PRV) vaccine, we could apply the PRV-gE antibody for determining wild-type virus infection and the PRV-gB antibody for evaluating vaccine immunization. The results were concluded as follows: (1) Nationally, the positive rate of PRV-gB was maintained at a high level (> 90%), while the positive rate of PRV-gE continued to decrease (from 22.17 to 13.14%). (2) The positive rates of PRV-gE were greatly varied in different geographical regions and swine farms (0~100%), while the positive rate of PRV-gB was generally high (> 90%). (3) The number of imported PRV attenuated vaccines were about twice that of domestic PRV attenuated vaccines, while the positive rate of PRV-gB was not significantly different (P > 0.05). (4) The performance of PR eradication developing or developed farms was better than the performance of common farms, with higher positive rate of PRV-gB (> 90%) and much lower positive rate of PRV-gE (nearly 0%). [ABSTRACT FROM AUTHOR]

Lead-free Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) powders were synthesized by sol-gel process followed by pressureless sintering. The structures of BCZT powders and ceramics, as well as the electrical properties, were studied. Through sol-gel process, BCZT powders could be obtained at a relatively low temperature of 800 °C. The obtained BCZT powders were cubic phase structure and well crystallized with an average grain size of 104.53 nm. The powders were further densified at 1400 °C, and BCZT ceramics with homogenous and dense (relative density > 95%) structure were obtained. The BCZT ceramics exhibited excellent electrical properties (εm = 8808, 2Pr = 24.48µC/cm2 and d33 = 485pC/N), which was comparable to those of lead-based piezoelectric ceramics, due to the high activity of the BCZT powders prepared by sol-gel process. [ABSTRACT FROM AUTHOR]

The nucleation process of graphene films prepared by pulsed laser deposition has been investigated in detail. It is found that graphene nucleates at the steps on the substrate surface firstly, from aggregation of nuclei into particles. High pulsed laser energy offers large incident energy for carbon particles deposited on the surface of the substrate, which is beneficial to the nucleation of graphene. A lot of steps are formed on the copper substrate due to the high temperature, so that the high incident energetic carbon species are able to form a stable nucleus at the steps. As the incident particles increases, the graphene nuclei are combined to grow together. Further, it is found that graphene tends to form few layer graphene particles instead of large graphene sheets. [ABSTRACT FROM AUTHOR]

Polycrystalline Bi4Ti3O12 thin films with various fractions of a-axis, c-axis and random orientations have been grown on Pt(111)/Ti/SiO2/Si substrates by laser-ablation under different kinetic growth conditions. The relationship between the structure and ferroelectric property of the films was investigated, so as to explore the possibility of enhancing ferroelectric polarization by controlling the preferred orientation. The structural characterization indicated that the large growth rate and high oxygen background pressure were both favorable for the growth of non-c-axis oriented grains in the Bi4Ti3O12 thin films. The films with high fractions of a-axis and random orientations, i e, f (a-sxis) = 28.3% and f (random) = 69.6%, could be obtained at the deposition temperature of 973 K, oxygen partial pressure of 15 Pa and laser fluence of 4.6 J/cm2, respectively. It was also noted that the variation of ferroelectric polarization was in accordance with the evolution non-c-axis orientation. A large value of remanent polarization (2Pr = 35.5 μC/cm2) was obtained for the Bi4Ti3O12 thin films with significant non-c-axis orientation, even higher than that of rare-earth-doped Bi4Ti3O12 films. [ABSTRACT FROM AUTHOR]

In order to overcome the purification difficulty of aluminum nitride (AlN) ceramics, the sintering of AlN ceramics with ammonium fluoride (NHF) as an additive had been studied. The results demonstrate that the addition of NHF evidently affects the phase compositions, the microstructure of grains and the contents of oxygen and nitrogen in the AlN sintered samples. NHF not only removes oxygen out of AlN grains but also reduces the total oxygen content in AlN ceramics. It is found that relatively high purity of AlN can be acquired when the molar ratio of NHF/O (oxygen element in raw AlN powder) increases to 0.8. With adequate amount of NHF, the Al-O-N phases are removed. SEM and TEM results show the hexagonal structures of AlN grains with clean triple-grain junctions. The oxygen content decreases to 0.55 wt% and nitrogen content increases to 33.7 wt%. Thermodynamic analysis illustrates the oxygen removing effects of NHF by the reaction of NH and AlO, which inhibits the formation of Al-O-N. NHF should be at least 2/3 of the oxygen content. [ABSTRACT FROM AUTHOR]

Al-doped ZnO (AZO) thin films were grown on c-sapphire substrates by laser ablation under different oxygen partial pressures ( P). The effect of PO2 on the crystal structure, preferred orientation as well as the electrical and optical properties of the films was investigated. The structure characterizations indicated that the as-grown films were single-phased with a wurtzite ZnO structure, showing a significant c-axis orientation. The films were well crystallized and exhibited better crystallinity and denser texture when deposited at higher P. At the optimum oxygen partial pressures of 10 - 15 Pa, the AZO thin films were epitaxially grown on c-sapphire substrates with the (0001) plane parallel to the substrate surface, i e, the epitaxial relationship was AZO (000 1) // AlO (000 1). With increasing P, the value of Hall carrier mobility was increased remarkably while that of carrier concentration was decreased slightly, which led to an enhancement in electrical conductivity of the AZO thin films. All the films were highly transparent with an optical transmittance higher than 85 %. [ABSTRACT FROM AUTHOR]

TNF receptor associated factor 3 (TRAF3), a member of the TRAF family of intracellular signaling proteins, can directly influence the phosphorylation status and activation of c-Jun N-terminal kinase, participating in CD40-induced apoptosis in carcinoma. However, its expression profile and function are still unclear in spinal cord injury (SCI). In this study, we performed an acute spinal cord contusion injury model in adult rats and detected the dynamic change patterns of TRAF3 expression in spinal cord. Western blot and immunohistochemistry revealed a striking upregulation of TRAF3 after SCI. Double immunofluorescence staining prompted that TRAF3 immunoreactivity was found in neurons rather than astrocytes. Moreover, co-localization of TRAF3/active caspase-3 was detected in neuronal nuclei. To further investigate the function of TRAF3, a neuronal cell line PC12 was employed to establish an apoptosis model in vitro. We analyzed the association of TRAF3 with active caspase-3 on PC12 cells by western blot and immunofluorescent labeling, which was parallel with the data in vivo. Additionally, knocking TRAF3 down with siRNA demonstrated the probable pro-apoptotic role of TRAF3 in the process of neuronal apoptosis. To summarize, we firstly uncover the temporal and spatial expression changes of TRAF3 in SCI. Our data suggest that TRAF3 might be implicated in central nervous system pathophysiology after SCI. [ABSTRACT FROM AUTHOR]

Using high aluminum refractory material as substrate at 1 400 °C, we studied the connections between several oxides such as Fe 2O 3, MnO 2, CuO, and the formation of defects such as coating crack, exfoliation, blistering, erosion, and fading away appeared in the application of high temperature infrared radiation coating. Analyses showed that thermal stress formed during the heating process due to the thermal expansion coefficient differential between the coating and the substrate, and volume effect caused by the crystal transferred when the temperature changed, which resulted in the coating crack and exfoliation. The gas produced by the reactions between components and binder or the components themselves during the heating process caused the coating blistering. The EMPA and XRD analyses show that oxides with low melting point in the penetrating area of the substrate may form eutectic with low melting point and produced thermal defects, which leads to the erosion by penetrating to the substrate. The valent changes of Fe 2O 3 and MnO 2 during the heating process cause the volatilization of the oxides or the pulverization of the coatings, resulting in the coating fades away easily at high temperature for a long time. [ABSTRACT FROM AUTHOR]

Epitaxial (0001)-oriented ZnCoO (= 0.01, 0.05 and 0.1) thin films were grown on c-sapphire substrates by pulsed laser deposition. The XRD analysis, optical transmittance and XPS measurements revealed that the Co substituted Zn ions were incorporated into the lattice of ZnO in ZnCoO thin films. The electrical properties measurements revealed that the Co concentration had a nonmonotonic influence on the electrical properties of the ZnCoO thin films due to the defects resulted from imperfections induced by Co substitution. The resistivity remarkably increased and the carrier concentration remarkably decreased in ZnCoO thin films after oxygen annealing at 600 ° under 15 Pa O pressure for 60 mins. Room-temperature ferromagnetic was observed and the ferromagnetic Co amount was smaller than the nominal Co concentration for ZnCoO samples before oxygen annealing. After oxygen annealing, the ZnCoO thin films exhibited paramagnetic behavior. It is suggested that the room-temperature ferromagnetic of ZnCoO thin films may attribute to defects or carriers induced mechanism. [ABSTRACT FROM AUTHOR]

BaTiO films were prepared on Pt/Ti/SiO/Si substrates by a laser chemical vapor deposition method. The effect of laser power ( P) on the electrical conductivity of the BaTiO films was investigated. The electrical resistivity of the grains was much higher than that of the grain boundaries, which indicated that the electrical conductivity along the grain boundary was dominant. For the BaTiO films, the conduction was mainly attributed to oxygen vacancies, and the electrical conductivity was strongly affected by their microstructures and the concentration of the charge carriers. With increasing the P, the grain size increased and the grain-boundary density decreased, which resulted in the decrease of the electrical conductivity. At the same time, the increase of T led to higher concentration of charge carriers, which resulted in the increase of electrical conductivity. [ABSTRACT FROM AUTHOR]

A TiO film was prepared on Pt/Ti/SiO/Si substrate by a laser chemical vapor deposition method. The rutile TiO film with pyramidal grains and columnar cross-section was obtained at a high deposition rate ( R = 11.4 μm h). At 300 K and 1 MHz, the dielectric constant ( ε) and loss (tan δ) of the TiO film were about 73.0 and 0.0069, respectively. The electrical properties of TiO film were investigated by ac impedance spectroscopy over ranges of temperature (300-873 K) and frequency (10-10 Hz). The Cole-Cole plots between real and imaginary parts of the impedance ( Z′ and Z′′) in the above frequency and temperature range suggested the presence of two relaxation regimes that were attributed to grain and grain boundary responses. The ionic conduction in the rutile TiO film was dominated by the oxygen vacancies. [ABSTRACT FROM AUTHOR]

BaTiO films were prepared on Pt/Ti/SiO/Si substrates by a laser chemical vapor deposition method. The effect of laser power ( P) on microstructure and dielectric properties of the BaTiO films was investigated. With increasing P from 62 to 108 W, the deposition temperature ( T) monotonously increased from 872 to 951 K. At T = 920 K ( P = 90 W), the BaTiO film had $$ (\overline{3} 01) $$ preferred orientation. At T ≥ 938 K ( P ≥ 98 W), the preferred orientation changed to $$ (\overline{3} 22)/(\overline{2} 23) $$. The deposition rate ( R) was 154.8-177.6 μm h. With increasing T, the surface morphologies changed from rectangular to pyramidal, and the dielectric constant ( ε) increased from 18.3 to 21.4 at 1 MHz and 300 K. [ABSTRACT FROM AUTHOR]

The compositionally graded BiNdTiO (BNT) thin films were prepared on Pt/Ti/SiO/Si substrates by sol-gel method. Their microstructure, ferroelectric and dielectric properties were investigated. The single-phase upgraded and downgraded BNT films were obtained with (117) preferred orientation. Compared to the homogeneous BNT films prepared by the same conditions, the remanent polarization ( P) and permittivity ( ε) of compositionally graded BNT films were significantly enhanced. The upgraded BNT film showed larger 2 P (34.9 μC/cm) and ε (509), and those of downgraded BNT film were 29.4 μC/cm and 505. Bi element in the downgraded BNT film accumulated near the interface of film/Pt bottom electrode, which deteriorated the compositional gradient and resulted in decreasing 2 P and ε compared to the upgraded BNT film. [ABSTRACT FROM AUTHOR]

ZnCoO (x = 0.01, 0.05 and 0.1) bulk ceramics were prepared through a two-step, solid state reaction method combined with spark plasma sintering technique. The single phase ZnCoO powders were synthesized using ZnO and CoO at 935 °C in air for 3 h. The ZnCoO bulks were prepared at sintering temperature from 900 to 1,100 °C for 5 min by SPS. The relative density of ZnCoO bulk ceramics sintered at 1,100 °C is higher than 99% of the theoretical value. The Structure, composition analysis, optical absorption, Raman and XPS measurements revealed that the Co substituted Zn ions and was incorporated into the lattice of ZnO in both of the single phase ZnCoO powders and bulk ceramics. Room- and low-temperature magnetization measurements reveal a paramagnetic behavior and that the paramagnetic Co amount is smaller than the nominal Co concentration for all of ZnCoO samples at 4 K. The paramagnetic magnetism of bulk ceramics is apparently larger than that of powders with the same composition. The electrical properties measurements reveal that the Co concentration has a slight influence on the electrical properties of ZnCoO bulk ceramics. The carriers concentration is about 1 × 10 cm and with the Co concentration increases the resistivity slightly increases from 3.56 × 10 (x = 0.01) to 5.58 × 10 (x = 0.1) Ωcm. [ABSTRACT FROM AUTHOR]

A BaTiO film was prepared on a Pt/Ti/SiO/Si substrate by a laser chemical vapor deposition method and was investigated by impedance spectroscopy over ranges of temperature (300-1073 K) and frequency (10-10 Hz). Plots between real and imaginary parts of the impedance ( Z′ and Z′′) suggest the presence of two relaxation regimes, which were attributed to grain and grain boundary responses. The conduction of both grains and grain boundaries obeys the Arrhenius format with activation energies of respectively 1.45 and 1.24 eV. The close activation energies indicate that the conduction in BaTiO film is mainly by oxygen vacancies. [ABSTRACT FROM AUTHOR]

The impedance and electrical conductivity of BaTiO film prepared by laser chemical vapor deposition were investigated as functions of temperature (300-1073 K) and frequency (10-10 Hz). The impedance response was resolved into two contributions, which were associated with the grains ( R C) and grain boundaries ( R C). With increasing temperature, both R and C decreased. R was much higher than R and C were close to C. Below 876 K, a step-like behavior was observed in the ac conductivity plots as functions of frequency due to two dispersion regions. The low-frequency dispersion was associated with grain boundaries and the high-frequency one corresponded to grains. The activation energies of grain conduction ( E) and grain boundary conduction ( E) were 0.20 and 1.49 eV, respectively, which indicated that the relaxation process in grains arose from hopping electron and that in grain boundaries from the diffusion of oxygen vacancies. [ABSTRACT FROM AUTHOR]

BaTiO film was prepared on Pt/Ti/SiO/Si substrate by the laser chemical vapor deposition method. A single-phase BaTiO film with $$ (\overline{3} 22)/(\overline{2} 23) $$ preferred orientation and columnar cross-section was obtained at high deposition rate (154.8 μm h). The dielectric constant ( ε) of the BaTiO film was 21, measured at 300 K and 1 MHz. The electrical properties of the BaTiO film were investigated by ac impedance spectroscopy from 300 K to 1073 K at 10 Hz to 10 Hz. Plots of the real and imaginary parts of the impedance ( Z′ and Z″) and electrical modulus ( M′ and M″) in the above frequency and temperature range suggested the presence of two relaxation regimes, which were attributed to grain and grain boundary responses. The ac conductivity plots as a function of frequency showed three types of conduction process at elevated temperature. The frequency-independent plateau at low frequency was due to dc conductivity. The mid-frequency conductivity was due to grain boundaries, while the high-frequency conductivity was due to grains. [ABSTRACT FROM AUTHOR]

BaTiO film was prepared on Pt/Ti/SiO/Si substrate by laser chemical vapor deposition. The microstructure and dielectric properties were investigated. The single-phase BaTiO film with random orientation was obtained. The surface consisted of round and rectangular grains, and the cross-section was columnar microstructure. The deposition rate ( R) was 135 μm h. The dielectric constant ( ε) and loss (tan δ) were 35 and 0.01, respectively, at 1 MHz. With increasing temperature, ε increased and showed a broad peak around 736 K, which indicated there might be a phase transition. [ABSTRACT FROM AUTHOR]

Pb(ZrTi)O (PZT) thin films were prepared on Pt/Ti/SiO/Si substrate by sol-gel method. The effect of annealing temperature on microstructure, ferroelectric and dielectric properties of PZT films was investigated. When the films were annealed at 550-850 °C, the single-phase PZT films were obtained. PZT films annealed at 650-750 °C had better dielectric and ferroelectric properties. The sandwich composites with epoxy resin/PZT film with substrate/epoxy resin were prepared. The annealing temperature of PZT films influenced their damping properties, and the epoxy-based composites embedded with PZT film annealed at 700 °C had the largest damping loss factor of 0.923. [ABSTRACT FROM AUTHOR]

In the present study, high-energy ball-milling technique was applied to barium dititanate (BaTiO) powders. The improvement in sinterability of the ball-milled powders was evidenced, as compared with the sintering behavior of unmilled powders. After ball-milling, BaTiO coarse powders were effectively ground into fine ones, whose maximum particle size was decreased from ~400 to ~40 μm and about 20 vol% nano-scaled particles were produced. After further consolidation by spark plasma sintering at 1,323 K, almost fully dense BaTiO ceramics (97.7% theoretical density) with a compact structure was obtained. But for BaTiO coarse powders, the ceramics with high densification was difficult to obtain even after being sintered at a high temperature of 1,423 K, whose relative density was only 90.5%. The room temperature permittivities and dielectric losses at 1 MHz of the BaTiO ceramics derived from fine powders and coarse powders were 32.9, 0.034 and 26.7, 0.053, respectively. The permittivity of BaTiO ceramics sintered from fine powders reached a maximum value (ε′ = 240, 100 kHz) at the Curie temperature of ~730 K,which was larger than that sintered from coarse powders (ε′ = 175, 100 kHz) due to lower porosity. The present work proved that high-energy ball-milling is a feasible way to improve the sinterability of BaTiO powders. [ABSTRACT FROM AUTHOR]

BiNdTiO (BNT-x, x = 0, 0.25, 0.50, 0.75 and 1.0) thin films were prepared on Pt/Ti/SiO/Si substrates by a sol-gel method. The microstructure, ferroelectric and dielectric properties of BNT-x thin films were investigated. The single-phase BNT-x thin films were obtained. With increasing Nd content, the preferred orientation changed from random to (117) and surface morphologies changed from the mixture of rod- and plate-like grains to rod-like grains. The Nd substitution improved the ferroelectric and dielectric properties of BTO films. BNT-x films showed better electrical properties at x = 0.50-1.0. BNT-0.75 film exhibited the best electrical properties with remanent polarization (2 P) of 26.6 μC/cm, dielectric constant ( ε) of 366 (at 1 MHz), dielectric loss (tan δ) of 0.034 (at 1 MHz), leakage current density ( J) of ±3.0 × 10 A/cm (at ± 5 V) and fatigue-free characteristics. [ABSTRACT FROM AUTHOR]

BiNdFeO (BNF) nanotube arrays were prepared by a sol-gel template method. The microstructure and phase were observed by scanning electron microscopy and transmission electron microscopy. Highly ordered nanotube arrays with BNF nanotubes of 200 nm diameter, 60 μm length, and 20 nm wall thickness were obtained. The BNF nanotube array capacitor showed ferroelectricity with a remanent polarization (2 P) of 68.7 μC/cm and a coercive electric field (2 E) of 141.9 kV/cm at frequency of 1000 Hz. The leakage current behavior of the BNF nanotube array was dominated by an ohmic conduction mechanism at E < 30 kV/cm and a space-charge-limited current mechanism at E = 30 kV/cm to 200 kV/cm. [ABSTRACT FROM AUTHOR]

BiNdFeO films were prepared on Pt/Ti/SiO/Si substrate by a sol-gel method, and annealed at different temperatures. The effect of annealing temperature on the crystal structure, dielectric, ferroelectric, and ferromagnetic properties was investigated. When the BiNdFeO films were annealed at 490−600°C, the single phase was obtained. BiNdFeO film annealed at 600°C showed good multiferroic properties with ɛ of 145 (at 1 MHz), M of 44.8 emu/cm, and 2 P of 16.6 μC/cm. [ABSTRACT FROM AUTHOR]

Highly conductive IrO2 thin films were prepared on Si (100) substrates by means of pulsed laser deposition technique from an iridium metal target in an oxygen ambient atmosphere. Emphasis was put on the effect of oxygen pressure and substrate temperature on the structure, morphology and resistivity of IrO2 films. It was found that the above properties were strongly dependent on the oxygen pressure and substrate temperature. At 20 Pa oxygen ambient pressure, pure polycrystalline IrO2 thin films were obtained at substrate temperature in the 300–500 °C range with the preferential growth orientation of IrO2 films changed with the substrate temperature. IrO2 films exhibited a uniform and densely packed granular morphology with an average feature size increasing with the substrate temperature. The room-temperature resistivity variations of IrO2 films correlated well with the corresponding film morphology changes. IrO2 films with the minimum resistivity of (42±6) μΩ·cm was obtained at 500 °C. [ABSTRACT FROM AUTHOR]

In this article the authors discuss aspects of research by D. E. Rase and R. Roy that appeared in the "Journal of the American Ceramics Society," noting that Rase and Roy reported the improper stoichiometry of barium titanate (Ba4Ti13O30) ceramics. An overview of the authors' research on the dielectric properties of Ba4Ti13O30 film prepared by laser chemical vapor deposition is presented.

MgO thin films were deposited on Si(100) substrates by laser ablation under various substrate temperatures ( T), expecting to provide a candidate buffer layer for the textured growth of functional perovskite oxide films on Si substrates. The effect of T on the preferred orientation, crystallinity and surface morphology of the films was investigated. MgO films in single-phase were obtained at 473-973 K. With increasing T, the preferred orientation of the films changed from (200) to (111). The crystallinity and surface morphology was different too, depending on T. At T=673 K, the MgO film became uniform and smooth, exhibiting high crystallinity and a dense texture. [ABSTRACT FROM AUTHOR]

A novel microwave-assisted sol–gel-hydrothermal method was employed to rapidly synthesize Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) powders. The effects of reaction time on the structure, crystallinity, purity and morphology of the products were investigated. The results of XRD, FTIR, SEM and TEM indicated that BCZT powders could be obtained in even 60 min at a low synthesis temperature of 180 °C, which were well-crystallized with stoichiometric composition and uniform grain size (~ 85 nm). BCZT ceramic derived from the rapidly-synthesized powders had a dense microstructure and good electrical properties (εm = 9579, d33 = 496 pC/N, 2Pr = 25.22 µC/cm2, 2Ec = 7.52 kV/cm). The significant electrical properties were closely related to the high activity of the BCZT powders, resulting from the rapid microwave-assisted sol–gel-hydrothermal process. [ABSTRACT FROM AUTHOR]

The foodborne pathogen Listeria monocytogenes (Lm) is a highly heterogeneous species and currently comprises of 4 evolutionarily distinct lineages. Here, we characterize isolates from severe ovine listeriosis outbreaks that represent a hybrid sub-lineage of the major lineage II (HSL-II) and serotype 4h. HSL-II isolates are highly virulent and exhibit higher organ colonization capacities than well-characterized hypervirulent strains of Lm in an orogastric mouse infection model. The isolates harbour both the Lm Pathogenicity Island (LIPI)-1 and a truncated LIPI-2 locus, encoding sphingomyelinase (SmcL), a virulence factor required for invasion and bacterial translocation from the gut, and other non-contiguous chromosomal segments from another pathogenic species, L. ivanovii. HSL-II isolates exhibit a unique wall teichoic acid (WTA) structure essential for resistance to antimicrobial peptides, bacterial invasion and virulence. The discovery of isolates harbouring pan-species virulence genes of the genus Listeria warrants global efforts to identify further hypervirulent lineages of Lm. Listeria monocytogenes isolates are highly heterogeneous and exhibit different levels of virulence. Here, the authors identify hypervirulent isolates that represent a hybrid sub-lineage of the major lineage II harbouring virulence factors from Listeria ivanovii and wall teichoic acids found in major lineage I. [ABSTRACT FROM AUTHOR]