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This paper studies the dynamics of a spinning three-body tethered satellite formation by a flexible multibody dynamics method. The tethered system is specially designed to constitute a Space Infrared Interferometric Telescope for a space exploration mission. Two sub-satellites are deployed from the main-satellite by using long flexible tethers and moving along trajectories of Archimedes spirals. Both of the large displacement and large deformation of the variable-length tethers are described by utilizing the Absolute Nodal Coordinate Formulation method in a framework of Arbitrary Lagrange-Euler (ANCF-ALE) description. The Natural Coordinate Formulation (NCF) method is used for describing the overall rigid motions of the three satellites. Considering the mass flow of tether element, the dynamic equations of tether element are derived by using the D'Alembert's principle. The governing dynamic equations of the system are obtained with a method of Lagrange multipliers. The tether deployment is achieved by regulating deployed velocity and applied jet forces. Numerical case studies are presented for investigating the parametric influences on the deployment dynamics of the tethered system by comparisons.

Supplemental material, DS_10.1177_0022034520937617 for MicroRNA-29b Promotes Subchondral Bone Loss in TMJ Osteoarthritis by J.L. Sun, J.F. Yan, S.B. Yu, J. Zhao, Q.Q. Lin and K. Jiao in Journal of Dental Research

A pre-cold-deformation process was applied for commercially pure titanium at cryogenic temperature to activate high-density deformation twins, and subsequent hot-deformation was used to induce dynamic recrystallization (DRX). Three major types of twins were effectively activated during cryogenic deformation, including { 11 2 ¯ 2 } contraction twins, { 11 2 ¯ 1 } extension twins, and { 10 1 ¯ 2 } extension twins. A special type of slipped { 11 2 ¯ 1 } “twins” was also activated by a sequential effect of twinning and slip. Selection of twinning variants followed Schmid's law well, where only the twinning systems with a Schmid factor of m ≥ 0.4 could be activated. The pre-activated twinning led to a remarkably stable flow stress at 500 °C up to a true strain of 1.0, due to the attainment of dynamic equilibrium between strain hardening and high-temperature softening. Two DRX stages occurred: (1) twin-active DRX stage, and (2) discontinuous dynamic recrystallization (DDRX) stage. The DRX mechanisms identified were twinning-induced DRX (or TDRX) and DDRX. While the low-temperature slip alone had little influence on DRX, the pre-activated { 11 2 ¯ 2 } twins, { 11 2 ¯ 1 } twins, { 10 1 ¯ 2 } twins and slipped { 11 2 ¯ 1 } “twins” contributed effectively to DRX in the form of spheroidization of twin lamellae due to twin-dislocation interactions, leading to a substantial grain refinement from ∼41 to ∼1 μm during subsequent hot-deformation.

The effect of temperature (from 77 to 473 K) on strain rate sensitivity, apparent and effective activation volume of ultrafine grained tantalum processed by equal-channel angular pressing (ECAP) is investigated in the present work. Microstructural characterization was performed using transmission electron microscopy (TEM) and electron-backscatter diffraction (EBSD). The strain rate sensitivity (SRS) was measured by strain rate jump tests at different temperatures. The SRS shows a monotonous increase with increasing the temperature. A small yield point phenomenon at 77 K during strain rate jump tests was observed because of the low mobility of screw dislocations. The Helmholtz free energy calculated according to the experimental data was estimated to be 1.14 eV. This suggests that the thermal activation process is controlled by dislocation slipping. However, the apparent and effective activation volumes show a power law dependence on the temperature, indicating a variation of rate controlling mechanism in the intermediate temperature range (from 373 to 473 K). It is concluded that the Peierls hill is much lower in the intermediate temperature thus the mechanism of intersection of dislocations becomes more difficult controlling the deformation instead.

The stress singularity order and characteristic angular function for a V-notch in a moderately thick plate with angularly heterogeneous elastic property are investigated where the first-order shear deformation plate theory is used. By introducing the typical terms in the asymptotic expansions of the displacement field near the singular point, the governing equations and radial boundary conditions of an angularly heterogeneous V-notch in a moderately thick plate are transformed into the characteristic ordinary differential equations with varying coefficients, which are uncoupled with respect to the in-plane displacement, anti-plane displacement and rotating angle of the mid-plane, respectively. The singularity order and characteristic angular function of the V-notch are yielded by applying the interpolating matrix method to solve the established characteristic equations. The present method is suitable for the singularity characteristic analysis for the V-notch under different radial boundary conditions and different elastic modulus variation models. The singularities for the V-notches in three differential elastic modulus variation models are evaluated and their singularity orders are compared. It is found that the stress singularity for the V-notch whose elastic modulus varies as a power function is the most serious, while the one whose elastic modulus varies as an exponential function is the weakest when free–free radial boundary condition is considered. The stress singularity for the V-notch under clamped–clamped boundary condition is the weakest, however, the one under free–free boundary condition is the strongest when the elastic modulus varies as a power function.

Organic electronics is emerging for large-area applications such as photovoltaic cells, rollable displays or electronic paper. Its future development and integration will require a simple, low-power organic memory, that can be written, erased and readout electrically. Here we demonstrate a non-volatile memory in which the ferroelectric polarisation state of an organic tunnel barrier encodes the stored information and sets the readout tunnel current. We use high-sensitivity piezoresponse force microscopy to show that films as thin as one or two layers of ferroelectric poly(vinylidene fluoride) remain switchable with low voltages. Submicron junctions based on these films display tunnel electroresistance reaching 1,000% at room temperature that is driven by ferroelectric switching and explained by electrostatic effects in a direct tunnelling regime. Our findings provide a path to develop low-cost, large-scale arrays of organic ferroelectric tunnel junctions on silicon or flexible substrates., Ferroelectric organic materials can be used for tunnel barriers in memory devices as a cheaper and eco-friendly replacement of their inorganic counterparts. Here, Tian et al. use poly(vinylidene fluoride) with 1–2 layer thickness to achieve giant tunnel electroresistance of 1,000% at room temperature.

Regular changes in ferroelectric and pyroelectric properties of P(VDF-TrFE) polymer thin films were observed when the films have a bent-deformation caused by external force. The deformation rate dependence of the remanent polarization, relative dielectric constant and pyroelectric coefficient of the P(VDF-TrFE) thin films were studied. The results demonstrated that there was an increase of ∼12.2% in the remanent polarization of the bent films between the maximum and the minimum bent-deformation rate. Pyroelectric coefficient of the bent P(VDF-TrFE) thin films was also enhanced compared with the flat P(VDF-TrFE) films. P(VDF-TrFE) films can still maintain good performance in ferroelectric and pyroelectric properties under bent deformation, which is meaningful to the potential application in flexible devices.

In the situation of thin-interbed reservoirs, the common seismic deconvolution can’t effectively improve the resolution because of the impractical assumptions of white noise to reflectivity and zero phase or minimum phase to seismic wavelet. In the paper we propose a method of seismic deconvolution which can improve the resolution obviously. Firstly we estimate the wavelet accurately based on the fourth-order cumulant and without these impractical assumptions. Then use the estimated wavelet to construct the shaping filter operator by the least-squares method, at last apply the shaping filter operator to seismic deconvolution and improve the resolution. The synthetic example and some real data results show the method can obtain the deconvolution result more closer to the reflection coefficients, and the recognition of thin-interbed reservoirs is enhanced obviously.

A cylindrical hexagonal-close-packed Ti sample was pre-deformed by dynamic compression to produce coarse-grained and ultrafine-grained structures in different parts of the sample followed by further dynamic compression to failure, making it possible to explore the effect of stored strain and grain boundary energy on shear banding in the material. A long shear band that formed during the final compression process passed through a complete diagonal of the sample. Electron backscattered diffraction was used to systematically investigate the shear-banding-induced structural evolution. Results show that the original stored energy in the matrix plays a significant role in the competition between deformation-induced grain refinement and grain growth, which determines the final average grain size in a shear band. Shear banding leads to grain reorientation such that one close-packed 〈 1 1 2 ¯ 0 〉 direction and one 〈 1 0 1 ¯ 0 〉 direction in most grains are parallel to the local shear direction and the normal direction to the local shear plane, respectively. The grain orientation in the shear band favours prismatic 〈a〉 slip, while the texture in the matrix, which is a stable compression texture, benefits the basal 〈a〉 slip. The results advance our understanding of the shear banding behaviour in heterogeneous deformation conditions and also the overall mechanical behaviour of materials under dynamic compression.

The deformation behaviour of ultrafine-grained hexagonal close-packed Ti processed by dynamic plastic deformation was investigated using electron microscopy techniques. Results show that the deformation twinning propensity in ultrafine-grained Ti decreases monotonously while the number of dislocations having the component increases with decreasing grain size, indicating that the transformation of the deformation mechanism from twinning to slip occurs and that the twinning mechanism does not change within the observed grain size range. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The scanning electron microscopy transmission Kikuchi diffraction technique was used to characterize the microstructure of ultrafine-grained Ti processed by dynamic plastic deformation at room temperature. Contrary to the general conception that twinning plays little role in the plastic deformation of ultrafine-grained hexagonal close-packed Ti, nanocrystalline { 1 1 2 ¯ 2 } and { 1 0 1 ¯ 2 } deformation twins were widely observed in the material. The observation provides insight into the deformation mechanisms and mechanical behaviour of nanostructured metals with hexagonal close-packed structures.

The effect of high energy electron irradiation on poly(vinlidene fluoride-trifluoroethylene) copolymer film with thickness about 180 nm has been studied. Both dielectric spectroscopy investigation and X-Ray Diffraction show that all-trans conformation of pre-irradiated films is transformed to trans-gauche conformation after irradiation. The relaxor behavior of irradiated sample obeys the modified Curie-Weiss and Vogel-Fulcher law. And the tunability is increased from 42% to 63% after irradiation.

Intense muon beams have very important applications by using pSR techniques and other methods. An experimental muon source (EMuS) as a parasitic facility at China Spallation Neutron Source (CSNS) is proposed. EMuS makes use of a small portion of the high power proton beam from the CSNS accelerator complex. It will provide an excellent platform for muon beam based multidisciplinary research, and will also serve as the development base for a future full-scale muon source at CSNS. The available proton beam power of 4 kW at 1.6 GeV can produce intense muon flux with a thick production target The muon yields with different target materials and shapes, and the muon collection efficiency have been simulated by using the FLUKA code. It is found that the graphite target of about 10-12 cm in thickness and rectangular in cross-section is a good choice, and that the collection at 90 degrees from the beam direction is the best for surface muons. It is found that 4-D emittance volume instead of two independent 2-D emittances should be used to define the relation between the optimal muon intensity and the muon channel acceptance, due to the asymmetry between the distributions in the two transverse phase planes. The collected muon intensities for both surface muons and cloud muons with different emittances have also been studied, which are important for designing the muon beam transport line. The intensities of positive and negative muons are in the orders of 10(5) mu(+)/s and 10(4) mu(-)/s, respectively. (C) 2012 Elsevier B.V. All rights reserved.

Resistive switching through electroresistance (ER) effect in metal-ferroelectric-metal (MFM) capacitors has attracted increasing interest due to its potential applications as memories and logic devices. However, the detailed electronic mechanisms resulting in large ER when polarisation switching occurs in the ferroelectric barrier are still not well understood. Here, ER effect up to 1000% at room temperature is demonstrated in C-MOS compatible MFM nanocapacitors with a 8.8 nm-thick poly(vinylidene fluoride) (PVDF) homopolymer ferroelectric, which is very promising for silicon industry integration. Most remarkably, using theory developed for metal-semiconductor rectifying contacts, we derive an analytical expression for the variation of interfacial barrier heights due to space-charge effect that can interpret the observed ER response. We extend this space-charge model, related to the release of trapped charges by defects, to MFM structures made of ferroelectric oxides. This space-charge model provides a simple and straightforward tool to understand recent unusual reports. Finally, this work suggests that defect-engineering could be an original and efficient route for tuning the space-charge effect and thus the ER performances in future electronic devices.

The effect of the thickness on the dielectric and ferroelectric properties of poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] copolymer thin films were investigated. The results show that the dielectric constant and tunability increase while the coercive field decreases with increasing film thickness. The film thickness also affects both the reversible and irreversible Raleigh parameters in the ac field dependence of dielectric constant. The observed phenomenon can be explained by the existence of interfacial layers between electrodes and film. No obvious thickness-dependent microstructure and ferroelectric transition temperature was observed.

Non-thermal plasma technology is a promising process for flue gas treatment. Microwave catalytic NOx and SO2 removal simultaneously has been investigated using FeCu/zeolite as catalyst. The experimental results showed that a microwave reactor with FeCu/zeolite only could be used to microwave catalytic oxidative 91.7% NOx to nitrates and 79.6% SO2 to sulfate; the reaction efficiencies of microwave catalytic reduction of NOx and SO2 in a microwave reactor with FeCu/zeolite and ammonium bicarbonate (NH4HCO3) as a reducing agent could be up to 95.8% and 93.4% respectively. Microwave irradiation accentuates catalytic reduction of SO2 and NOx treatment, and microwave addition can increases SO2 removal efficiency from 14.5% to 18.7%, and NOx removal efficiency from 13.4% to 18.7%, separately. FeCu/zeolite catalyst was characterized by X-ray diffraction (XRD), X-ray photoelectron spectrum analysis (XPS), scanning electron microscopy (SEM) and the Brunauer Emmett Teller (BET) method. Microwave catalytic NOx and SO2 removal follows Langmuir–Hinshelwood (L–H) kinetics.

Electrical properties of poly(vinylidene fluoride trifluoroethylene) [P(VDF-TrFE)] copolymer thin film grown by sol-gel method on flexible polymer substrate were studied. Two types of electrodes, NiFe and Al, were employed to form NiFe/P(VDF-TrFE)/NiFe and Al/P(VDF-TrFE)/Al capacitor structures. The capacitors with NiFe electrodes exhibit higher remnant polarization, lower coercive field, higher dielectric constant and pyroelectric coefficient than the samples with Al electrodes. The improved properties can be attributed to less defects, more charge injection and better interfaces in the NiFe/P(VDF-TrFE)/NiFe capacitor.

The capacitance of poly(vinylidenefluoride-trifluoroethylene) copolymer ultrathin films was investigated as a function of frequency, ac drive, and temperature. In the ferroelectric (FE) phase, the capacitance of the copolymer films increases with ac drive and shows an ac dielectric nonlinearity. On the contrary, the capacitance decreases with ac drive in the paraelectric (PE) phase. Since the maximum ac drive is much smaller than the coercive field, the contribution of the polarization switching to the increase of the capacitance can be ruled out. The ac drive dependence of the capacitance is believed to reflect the information of the molecular configuration, the intra- and interchain interactions.

FeCoCu/zeolite 5A was used as a catalyst for microwave catalytic desulfurization and denitrification and for microwave catalytic reduction of SO2 and NOx with ammonium bicarbonate ( NH4 HCO3 ) as a reducing agent. Microwave catalytic desulfurization and denitrification efficiency attained 99.5 and 86.1%, respectively. The reaction efficiencies of microwave catalytic reduction of SO2 and NOx could be up to 95.8 and 95.1% separately; the optimal microwave power and empty bed residence time on microwave catalytic reduction of SO2 and NOx simultaneously are 280 W and 0.358 s, respectively. Microwave accentuates catalytic reduction treatment, and microwave addition can increase the SO2 and NOx removal efficiency. The microwave catalytic SO2 and NOx removal follows the Langmuir-Hinshelwood model.

Well-crystallized 0.5 mol% Mn doped Pb0.5Sr0.5TiO3 ferroelectric films with remarked ferroelectric properties were prepared by the chemical solution deposition. Optical response of PSMT05 films was investigated by transmittance spectroscopy in the wavelength range from 280 to 1100 nm, which can be simulated by Tauc-Lorentz and Cauchy models and the optical parameters were obtained from the simulations. The fitting of the absorption coefficient with Tauc's law suggests the direct interband transition in PSMT05 films (the band gap is 4.12 eV). Below the band gap, there is a weak band tail absorption region and the band tail energy is about ∼240 meV.

Relaxor ferroelectric terpolymer, Poly (vinylidene fluoride-trifluoroethylene-chlorofloroethylene) can be applied in many modern electronics systems. In this paper, the terpolymer films were deposited on aluminum-coated silicon substrates by horizontal Langmuir-Blodgett technology. The X-ray diffraction pattern indicates that the films have good crystallinity. The optical dispersion of the films were measured by variable-angle spectroscopic ellipsometry over a range from 300–1300 nm. The data Ψ and Δ at multiple incident angels (θ = 75° and 85°) were fitted using the Cauchy model. The refractive index n, the extinction coefficient k and the thickness of each film were obtained.

Polyvinylidene fluoride (PVDF) films and copolymer films of vinylidene fluoride and trifluoroethylene P(VDF-TrFE) have great potential applications in uncooled infrared detection due to their good pyroelectricities and ferroelectricities. It is important to investigate the mechanism of their electrical transport. In our present work, we found the differential conductivities of P(VDF-TrFE) films exhibit a sharp peak near the coercive field. And it is proposed that the peak is caused by the delocalization of polarons during the polarization inversion.

Photocatalysis is a promising technology for treatment of gaseous waste; its disadvantages, however, include causing secondary pollution. Biofiltration has been known as an efficient technology for treatment volatile organic compounds (VOCs) at low cost of maintenance, and produces harmless by-products; its disadvantages, include large volume of bioreactor and slow adaptation to fluctuating concentrations in waste gas. A bench scale system integrated with a photocatalytic oxidation and a biofilter unit for the treatment of gases containing toluene was investigated. The integrated system can effectively oxidize toluene with high removal efficiency. The photocatalytic activity of N-TiO(2)/zeolite was evaluated by the decomposition of toluene in air under UV and visible light (VL) illumination. The N-TiO(2)/zeolite has more photocatalytic activity under complex light irradiation of UV and visible light for toluene removal than that of pure TiO(2)/zeolite under UV or visible light irradiation. N-TiO(2)/zeolite was characterized by scanning electron microscopy (SEM), X-ray photoelectron spectrum analysis (XPS), Fourier transform infrared spectroscopy (FT-IR), and as-obtained products were identified by means of gas chromatography/mass spectrometry (GC/MS). Results revealed that the photocatalyst was porous and was high photoactive for mineralizing toluene. The high activity can be attributed to the results of the synergetic effects of strong UV and visible light absorption, surface hydroxyl groups. The photocatalytic degradation reaction of toluene with the N-TiO(2)/zeolite follows Langmuir-Hinshelwood kinetics. Toluene biodegradation rate matches enzymatic oxidation kinetics model.

Background and purpose To evaluate the potential neuroprotection against subsequent cerebral infarction conferred by a prodromal transient ischaemic attack (TIA). Methods Various measures, including blood pressure, blood serum glucose, serum lipids, cardiovascular imaging and changes to NIHSS scores were evaluated upon admission and discharge for patients presenting with ischaemic stroke with or without prodromal TIA (n = 60 per group). Results When all patients from each group were considered together, no significant group effects emerged. However, when the NIHSS difference scores from the prodromal TIA group were subdivided based on (i) prodromal TIA lasting up to 4 min; (ii) two prodromal TIA attacks and/or; (iii) prodromal TIA-stroke interval within 7 days separately, patients in subgroups 1 and 2 exhibited significantly better outcome on discharge. There was no significant effect found in subgroup three although this TIA group did show better outcome in considering the NIHSS changes. Conclusions Prodromal TIA prior to cerebral infarction may result in an ischaemic tolerance effect. Moreover, the neuroprotection conferred by the TIA may be associated with the duration and the frequency of the TIA, although the relationship between the TIA-stroke interval and prognosis is not clear.

LaNiO 3 (LNO) thin films were deposited by radio frequency magnetron sputtering on n-type Si (100) wafers at room temperature (RT). The as-sputtered LNO thin films were amorphous and had very high RT electrical resistivity even after post-annealing at 800 °C. The amorphous as-sputtered LNO films could be transformed to polycrystalline LNO films in rhombohedral phase by heating at 400 °C in an O 2 atmosphere at pressure ranging from 1.5 to 8.0 MPa. Very low RT resistivity of LNO films were obtained by this high oxygen-pressure processing. The lowest value was as low as 1.09 × 10 − 4 Ω cm by processing at oxygen pressure of 8 MPa. Such preparation of LNO thin films is compatible with the Si-based readout integrated circuits. Highly (100)-oriented perovskite structure of Pb(Zr 0.52 Ti 0.48 )O 3 thin films was formed on this rhombohedral phase LNO, and good ferroelectricity could also be obtained on these HOPP-processed rhombohedral phase LNO films.

Pure Fe, Cr and Al powders were used to mix with an additive to prepare a powder-mixed paste. Fe–25Cr–5Al honeycombs were fabricated by extruding the powder-mixed paste, then dried and sintered. The volume shrinkage and the apparent density of extruded honeycombs after drying and sintering were measured. The effect of sintering temperature and time on the volume shrinkage, the apparent density and the structure of honeycombs had been studied. The results show that the volume shrinkage and the apparent density of metallic honeycombs increase with temperature, the volume shrinkage ranging from 25% to 53%, and the apparent density ranging from 1.0 g/cm3 to 1.7 g/cm3. When sintering at 1250 °C, the volume shrinkage and the apparent density of metallic honeycombs increase with time, reach a maximum at 35–40 min, then decrease. The structure of sintered honeycombs consists of α-Fe, Fe–Cr–Al compounds and Al2O3.

Polarization switching kinetics is one of the key issues for future development of nanoelectronic devices based on ferroelectrics. Up to now, such kinetics still remains poorly studied despite its crucial impact on the device performances. Here, the switching mechanism in 11-nm-thick ferroelectric films of pure homopolymer of polyvinylidene fluoride is investigated. While the usual mechanism involves nucleation and growth of domains, a homogeneous ferroelectric switching is evidenced in such ultrathin films. Indeed, the dependence of the switching rate on applied voltage reveals a critical behavior with the existence of a true threshold field (of $\ensuremath{\sim}0.26\phantom{\rule{0.16em}{0ex}}\mathrm{GV}/\mathrm{m}$) which is required to overcome the energy barrier to reverse the whole polarization homogeneously as suggested by Landau-Ginzburg mean-field theory. Such finding not only supports few previous works but also raises the question on the general aspect of such homogeneous mechanism that might exist in any other nanoscale ferroelectric materials.

The β phase stability in poly(vinylidene fluoride/trifluoroethylene) [P(VDF-TrFE)] thin films was studied below 300 K using X-ray diffraction and polarization-electric-field (P-E) hysteresis loops measurements. On as-grown samples, an irreversible partial order-disorder transformation at T β ∼ 250 K, namely, the β relaxation temperature, was evidenced by the appearance of an additional X-Ray diffraction peak above T β as well as changes on the P-E loops on heating after the first cooling. This order-disorder-like transformation which is attributed to an all-trans order to helical disorder transition is suggested to take place in defect-rich regions like crystal-amorphous interphases and/or crystalline areas with randomly distributed TrFE defect-like units. © 2015 AIP Publishing LLC.

Cotton stalk pyrolysis behavior and mechanism were studied based on the multi-scanning method. The results showed that cotton stalk pyrolysis zone during 30~600 ℃ could be divided into four regions, namely, water loss, depolymerization "glass transition", main pyrolysis and charring stage. During the main reaction zone TG curves and differential TG curves were moving to high temperature. The activation energy E of the main stage of pyrolysis was solved by FWO and FRL method respectively. The results showed that the activation energy E was very stable in the conversion rate of 10% to 70%. The results of the two solving methods were very close and had a high degree of linear fitting. Experimental data were analyzed by the non-linear fitting, and the mechanism of cotton stalk pyrolysis met Avrami-Erofeev equation. The reaction value of series (grade) was 0.4. The mechanism function forms are

SrTiO3 (STO) thin films with (200) preferential orientation were deposited on p-Si(100) substrates at 700°C by RF magnetron sputtering technique. Their leakage current mechanisms with metal-insulator-semiconductor (MIS) structures were investigated. It was found that the leakage current mechanisms followed the space charge limited current (SCLC) under the low applied electric filed and the Poole-Frenkel emission under the high one. In addition, the resistivity was higher than 1011Ω · cm until the voltage up to 10 V (corresponding to the electric field of 1.54 × 103 kV/cm), indicating that the STO films have good insulation properties.

The TiO2:Ti film was prepared as an alternative of the absorber layer for infrared thermal detectors. The as-deposited film was composed of TiO2 and Ti with a ratio near 5:1. To improve its absorption in infrared region, the film was etched in the diluted H2O2 solution. The etching process made the film porous and reduced the concentration of the free electron in the etched film, which decrease the reflection of the films and subsequently increase their absorption. The maximum absorption of the acid-treated Ti-based film was about 90% for the infrared radiation near 1500 cm−1. The resistivity of the etched films has been derived from four probe method with a two-layer model and from infrared spectrum by simulating it with Drude model. The values of resistivity from the two methods are in good agreement.

The Pb1−xLaxTiO3 (PLT) ferroelectric thin films on Pt/Ti/SiO2/Si(1 0 0) substrates were fabricated by a sol–gel process. The infrared optical properties of PLT thin films with x=0.1, 0.2, 0.25 on platinized silicon Pt(1 1 1)/Ti/SiO2/Si(1 0 0) substrates were studied by infrared spectroscopic ellipsometry (IRSE) technique in the wavelength region from 2.5 to 12.6 μm. The infrared optical constants were obtained by fitting the IRSE data using a classical dielectric function model. The refractive index increases, and the extinction coefficient decreases as wavenumber increases in the measured infrared region. The refractive index of PLT thin films decreases as the La contents increase in the films.

PbZr0.40Ti0.60O3/La x Sr1 − x CoO3 (PZT/LSCO) heterostructures have been grown on Si-based substrates by chemical solution routes. X-ray diffraction analysis showed that PZT on LSCO are polycrystalline with (110) orientation and entirely perovskite phase. The resistance of LSCO is strongly affected by the ratio of La/Sr and the annealing atmosphere for the LSCO thin films. The ferroelectricity of PZT is strongly dependent on LSCO electrode, the P-E hystersis loops of PZT deposited on LSCO which annealed in air is more asymmetry than that annealed in oxygen. At the applied electric field of 300 kV/cm, all PZT films have the resisitivity larger than 1010 Ω · cm. The fatigue resistance is strongly affected by the resistance of the LSCO electrode. The ferroelctric properties are strongly improved by LSCO buffer layer between PZT and Pt bottom electrode.

PbZr0.4Ti0.6O3/La0.5Sr0.5CoO3 heterostructures have been grown on Pt/Ti/SiO2/Si substrates by chemical solution routes. Optical properties of the PbZr0.4Ti0.6O3/La0.5Sr0.5CoO3 heterostructures were studied by infrared spectroscopic ellipsometry (IRSE) in the spectral range of 2.5–12.5 μm. The optical constants of PbZr0.4Ti0.6O3 and La0.5Sr0.5CoO3 thin films were determined by fitting the IRSE data using a classical dielectric model and a Drude dielectric model, respectively. For PbZr0.4Ti0.6O3 thin films, the refractive index decreases and the extinction coefficient increases as the wavelength increases. For La0.5Sr0.5CoO3 thin films, the refractive index and the extinction coefficient increase as the wavelength increases. The absorption coefficient of La0.5Sr0.5CoO3 thin films is greater than 104 cm-1 for the wavelength range of 2.5–12.5 μm. The absorption coefficient of PbZr0.4Ti0.6O3 thin films on a La0.5Sr0.5CoO3/Pt/Ti/SiO2/Si substrate is smaller than that on a Pt/Ti/SiO2/Si substrate by a factor of two.

Barium strontium titanate (Ba 0.9 Sr 0.1 TiO 3 ) ferroelectric thin films have been grown on Pt/Ti/SiO 2 /Si substrates by a modified chemical solution route. X-ray diffraction and Raman spectroscopy measurements show that the films have an excellent crystallinity and crystallize in a tetragonal structure. Field-emission scanning electron microscopy and atomic force microscopy investigations show that the films have a columnar structure with large grains of 80-200 nm in diameter. For an electric field of 320 kV/cm, the remnant polarization and the coercive field are 7.8 μC/cm 2 and 56 kV/cm, respectively. The optical constants (n, k) of the Ba 0.9 Sr 0.1 TiO 3 thin films are obtained by spectroscopic ellipsometry in the spectral range between 0.3 and 1.7 μm, and the band-gap energy is determined to be approximately 3.6 eV.

La0.5Sr0.5CoO3 (LSCO) films have been grown on Si (100) by a metalorganic chemical liquid deposition (MOCLD) technique using lanthanum acetate, strontium acetate and cobalt acetate as the starting materials. Subsequent PbZr0.5Ti0.5O3 (PZT) films were deposited onto LSCO films by a modified sol-gel method. Field-emission scanning electron microscopy and X-ray diffraction analysis show that PZT and LSCO films are polycrystalline and entirely perovskite phase. At an applied electric field of 250 kV/cm, the Pt/PZT/LSCO capacitor shows no polarization fatigue after 3×109 switching cycles and an internal electric field; the remnant polarization Pr and the coercive field Ec are about 22 μC/cm2 and 73 kV/cm, respectively. The dielectric constant of PZT films is 650 at a frequency of 1 kHz.

LaNiO 3 (LNO) films with a surface roughness rms of 0.384 nm and a sheet resistance of about 200 Ω were prepared on SrTiO 3 and Si/SiO 2 substrates respectively by rf magnetron sputtering technique. The surface of LNO on Si/SiO 2 substrate is smoother than that on SrTiO 3 substrate. A nominal 2-monolayer (ML) poly(vinylidenefluoride-trifluoroethylene) film with a thickness of about 3 nm was deposited on LNO coated Si/SiO 2 substrate by Langmuir–Blodgett (LB) technology. Piezoresponse force microscopy (PFM) measurements show that the LB films demonstrate an obvious feature of polarization switching and good voltage durability. The results suggest that the ultrathin polymer films may be utilized to explore ferroelectric tunnel junctions.

The effects of alternating electric field on the fatigue behaviors of poly(vinylidene fluoride–trifluoroethylene) copolymer films were investigated. The value of the remanent polarization ( P r ) reached a maximum with the increase of cycle number of alternating electric filed, and then decreased as observed from the curve of polarization vs. switching cycles. It was found that the maximum point is associated with the frequency of alternating electric field. Dual effects, i.e., polarization enhancement and degradation, were supposed to coexist during the process of fatigue. A model considering the two effects was proposed to describe the fatigue behaviors, and the simulated data fit well with the experimental data.

A biofilter packed with immobilized Thiobacillus sp. ST22 was investigated for the treatment of gases containing dimethyl sulfide (DMS). Thiobacillus sp. ST22 was immobilized using a sodium alginate, polyvinyl alcohol and powdered activated carbon as entrapping materials. The experimental results showed that the removal of DMS achieved an efficiency of 99.5%. The optimal spray density and empty bed residence time (EBRT) were 0.17 m3·m−2·h−1 and 21 s, respectively. Bacterial communities in the biofilter were assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), which plays a dominant role in the biological processes of simultaneous sulfur oxidation and sulfate reduction. The results showed that Thiobacillus sp. ST22, delta proteobacterium were the predominant bacteria. Dimethyl sulfide can be oxidized into H2SO4, CO2 by Thiobacillus sp. ST22 biooxidation in the outer zones of immobilized cell beads due to aerobic conditions. Dimethyl sulfide can be degradated in...

Lead zirconate titanate PbZr0.50Ti0.50O3 (PZT) ferroelectric thin films were successfully deposited on Pt(1 1 1)/Ti/SiO2/Si substrates by a modified sol–gel method using zirconium nitrate as a substitute for the conventional zirconium alkoxide. The precursor solutions were hydrolyzed with different H2O/Pb ratios. The effect of hydrolysis ratios of the solution on the microstructure for the PZT thin films were investigated via X-ray diffraction (XRD) and atomic force microscopy (AFM) techniques. The XRD results show that the PZT films exhibit (1 1 1)-orientation and the degree of the (1 1 1)-orientation decreases with the increase of hydrolysis ratio. These results indicate that the ferroelectric behavior can be improved by an appropriate choice of H2O/Pb ratio.

We report preparation of a novel barrier structure for high T/sub c/ superconducting multilayer Josephson junctions using a simple composite target technique. Such a barrier consists of Y/sub x/Pr/sub 1-x/Ba/sub 2/Cu/sub 3/O/sub y/ with a continually varied concentration of yttrium. In this barrier no lattice mismatch and other incompatibility problems occur between adjacent layers. Thus the formation of interfacial defects and structural strain can be mostly prevented. The Josephson coupling takes place at the electrically formed interfaces rather than the structural interfaces. A particular feature of these junctions is that the effective thickness of the barrier strongly depends on the measuring temperature and the concentration gradient. The absence of the structural interface in the weak link region greatly enhances the reproducibility and the performance of these junctions.

The temperature dependence of excess current in the ramp-edge YBa 2 Cu 3 O y /PrBa 2 Cu 3 O y /YBa 2 Cu 3 O y Josephson junctions has been studied. The experimental results indicated that excess current may be caused by Andreev reflection at the SN interfaces of SNS junctions. It was found that the temperature dependence of excess current is the same as that of order parameter at the N side of SN interface. This is in agreement with the prediction of theory. The amplitude of the excess current is the same order as that of critical current.

Highly (100)-oriented LaNiO3 (LNO) films directly on Si substrates were prepared by a simple chemical solution technique using lanthanum nitrate and nickel acetate as the start material sources. Highly (100)-oriented PbZr0.30Ti0.70O3 (PZT30/70) thin film was fabricated subsequently on the LNO-coated Si substrates using a modified sol-gel method. The orientation of the PZT and LNO thin films was characterized by X-ray diffraction (XRD). The resistivity of the LNO thin film at room temperature (300 K) is 7.6×10−4 Ωcm. The remmant polarization (Pr) and coercive field (Ec) of the Pt/PZT/LNO/Si capacitor were 10.5–16.8 μC/cm2 and 20.5–31.6 kV/cm with the variation of electric field (100–200 kV/cm). The values of dielectric constant and dissipation factor of 10 kHz were 700 and 0.019, respectively. After 108 switching cycles, the net-switched polarization values of the capacitor drop to 95, 62, and 37% of their initial values under different electric fields ranging from 100 to 200 kV/cm, respectively.

PbZr0.5Ti0.5O3 thin films have been prepared on Pt (111)/Ti/SiO2/Si substrates by a modified sol–gel technique. The PZT films were annealed layer by layer using a rapid thermal annealing (RTA) method during the spin-coating process. A novel route was used to obtain PZT films with different single-annealed-layer in thickness from the same precursor solution. It is found that the degree of (111) orientation of the films increases with the reduction thickness of single-annealed-layer. As the thickness of single-annealed-layer drops to 40 nm, the film shows a high degree of (111) preferred orientation. The decrease of single-annealed-layer thickness also leads to the increase of the remanent polarization and the dielectric constant.