Showing papers in "Integrated Ferroelectrics in 2013"
TL;DR: In this article, a re-programmable antifuse field programmable gate array (FPGA) integrated circuit is presented, the FPGA comprising: a plurality of CeRAM resistive switching elements forming a connection block, the switching elements capable of being switched from a conductive (ON) state to a non-conductive (OFF) state and back to a conducting state.
Abstract: A re-programmable antifuse field programmable gate array (FPGA) integrated circuit, the FPGA comprising: a plurality of CeRAM resistive switching elements forming a connection block, the switching elements capable of being switched from a conductive (ON) state to a non-conductive (OFF) state and back to a conductive (ON) state; a plurality of logic elements forming a logic block; and a programming circuit for turning the CeRAM switching elements OFF and ON to connect the logic elements to form the FPGA.
62 citations
TL;DR: In this paper, the properties of cubic perovskite prototypes PbTiO3 (PTO), STO, and SZO were investigated via first principles calculation using the density functional theory as implemented in CASTEP computer code.
Abstract: The properties of cubic (Pm3m, 221 space group) perovskite prototypes PbTiO3 (PTO), SnTiO3 (STO), and SnZrO3 (SZO) were investigated via first-principles calculation using the density functional theory as implemented in CASTEP computer code. The lattice parameters of PbTiO3 (as the reference compound) were calculated. The accuracy values of the calculation functional (GGA-PBEsol) were acceptable relative to the experimental values with typical error of approximately 0.6% underestimate. The independent elastic constants (C11, C12, and C44) and bulk modulus, B, were obtained and analyzed. The density of state studies indicated hybridizations among anion O 2p, cation Pb 6s/Sn 5s and the Ti 3d/Zr 4d states of PTO, STO, and SZO. An indirect band gap was respectively obtained for both PTO and STO at the X-G point. A direct band gap was attained for SZO at the X-X point along the high-symmetry direction in the Brillouin zone. The born effective charge values of PTO, STO, and SZO were attributed to the responses ...
39 citations
TL;DR: The microstructure and morphology of P(VDF-TrFE) thin films annealed at different temperatures (70°C-160°C) were investigated by atom force microscope and X-ray diffraction techniques.
Abstract: Ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] (70/30) copolymer thin films were prepared by spin-coating method. The microstructure and morphology of P(VDF-TrFE) thin films annealed at different temperatures (70°C-160°C) were investigated by atom force microscope and X-ray diffraction techniques, which reveal the crystallization of P(VDF-TrFE) films is greatly affected by the annealing temperature. With the increase of annealing temperature, the grains of P(VDF-TrFE) thin film change from small spheroids to long needle-like structures. The most rapid change occurs between 136°C–140°C. The surface roughness and the grain size of P(VDF-TrFE) film show similar change with the annealing temperature.
34 citations
TL;DR: In this paper, the melting process of nanoparticles is the uneven transition process of atomic structures from order to disorder, and the dominant mechanisms of melting process are analyzed from potential energy temperature relationship, radial distribution function, mean square displacement and atomic evolution configuration.
Abstract: In the application process of nanoparticles, the melting process plays an important role. Holding the melting characteristics of nanoparticles can essentially improve the correlative technical level. To study the melting characteristics of silver nanoparticles, melting processes of silver nanoparticles are investigated using molecular dynamics simulation. Simulation results show that the microscopic melting process of nanoparticles is the uneven transition process of atomic structures from order to disorder. Also, the melting point of 3 nm particle with 856 atoms is about 815 K and the heat capacity of nanoparticles is negative near the melting temperature. The dominant mechanisms of melting process are analyzed from potential energy temperature relationship, radial distribution function, mean square displacement and atomic evolution configuration. We also found that nanoparticles bunch up due to high surface energy for multi-nanoparticles when the temperature is lower than the melting point. And, when na...
32 citations
TL;DR: In this article, the structure and electronic properties of normal spinel ZnFe2O4 have been investigated using density functional theory (DFT) within the generalized gradient approximation (GGA) and the local density approximation (LDA).
Abstract: The structure and electronic properties of normal spinel ZnFe2O4 have been investigated using density functional theory (DFT) within the generalized-gradient approximation (GGA) and the local density approximation (LDA). The calculation results show that GGA/RPBE with ultrasoft pseudopotential method is a good method in predicting the crystal structures of the normal spinel ZnFe2O4. The results also indicate that the normal spinel ZnFe2O4 is direct gap semiconductor. There is a very strong hybridization between the Fe 3d state and the O 2p state, and a very strong hybridization between the Zn 3d state and O 2p state. The Zn−O bonds and Fe−O bonds have a covalent character.
30 citations
TL;DR: In this article, an optimizing method for binary nanofluids is proposed, which is conducted by removing the well dispersed nanoparticles from the suspensions with higher concentrations and regaining the required concentrations of nanoparticles based on ratio of varying absorbency.
Abstract: In order to apply the technique that nano-particles enhance the heat and mass transfer to the ammonia-water absorption refrigeration, several types of ammonia water nanofluids were prepared by two-step method. An optimizing method for preparation binary nanofluids is proposed in this paper, which is conducted by removing the well dispersed nanofluids from the suspensions with higher concentrations and regaining the required concentrations of nanofluids based on ratio of varying absorbency. The performance of the optimizing method on dispersion situation of nanofluids is evaluated by observing sedimentation and measuring the absorbency. The results show that the dispersion situation of SiC, TiN, TiO2 nanofluid mainly depends on the dispersive characteristics and hydrophilicity of nanoparticles when the PH value of basefluid is fixed and no dispersant is added. Al2O3, Fe2O3, ZnFe2O4 nanoparticles are hardly to disperse in ammonia water directly but their dispersion situations can be greatly improved by addi...
27 citations
TL;DR: In this paper, a piezoelectric energy harvesting shock absorber (PEHSA) system for vehicles was developed to act as an energy harvester that converts vibration energy to electrical energy.
Abstract: Only ∼20% of a vehicle's fuel consumption is used for overcoming air drag force and friction with the road. Vibration energy produced during driving is dissipated by shock absorbers in the vehicle suspension. A new Piezoelectric Energy-Harvesting Shock Absorber (PEHSA) system for vehicles has been developed to act as an energy harvester that converts vibration energy to electrical energy. Cylindrical piezoelectric transducers are combined with the cylinder of the shock absorber to generate electricity from changes in fluid pressure produced by piston vibrations. A multiphysics simulation was performed using COMSOL Multiphysics to determine the characteristics of the PEHSA system.
26 citations
TL;DR: In this paper, the photocatalytic activity of CeFeO3 nanosheets was investigated in experimental simulation wastewater containing 10mg/L methylene blue (MB).
Abstract: Using Ce(NO3)3·6H2O and Fe(NO3)3·9H2O as raw material, the CeFeO3 nanoparticles was synthesized by a microwave process. The products was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS).The results show that the CeFeO3 is single phase perovskite, and its morphology is nanosheets with nearly 40 nm thickness. The prepared nanosheets has an optical band gap of 1.77 eV, and exhibits strong visible-light absorption. The photocatalytic activity of CeFeO3 nanosheets was investigated in experimental simulation wastewater containing 10 mg/L methylene blue (MB). When the MB solution was irradiated by 90 min in the presence of CeFeO3 nanosheets under visible-light, the degradation rate of MB nearly reached to 100%. The photocatalytic experiment indicates that the prepared CeFeO3 nanosheets was highly visible-light activities for decomposition of sewage.
24 citations
TL;DR: In this paper, a multi-mechanism energy harvester (MMEH) was proposed, which combines magnetostrictive and inductive mechanisms with a shape and size similar to an AA battery.
Abstract: Multi-Mechanism Energy Harvesters (MMEHs) combining magnetostrictive and inductive mechanisms with a shape and size similar to an AA battery. Included are MMEHs with (a) an inductive mode: a cylindrical tube, a rod lengthwise within the tube, permanent magnets with opposing polarities at opposing ends of the tube, an annular oscillatory magnet in the tube and between the magnets and around the rod; and a primary coil around the tube and oscillatory magnet, such that relative movement between the magnet and coil induces electrical current in the coil; and (b) a magnetostrictive mode comprising: piezoelectric cymbal transducers on opposing ends of the tube and comprising a magnetostrictive material surrounded by a secondary coil, such that movement of the magnetostrictive material induces voltage in the secondary coil. During use, electrical energy can be harvested from the relative motion between the magnet and coil and from the magnetostrictive material.
23 citations
TL;DR: In this article, the capacitive properties of the Mn3O4, graphene and graphene/Mn3O 4 composites were investigated by galvanostatic charge/discharge, cyclic voltammetry (CV) and electrochemical impendence spectroscopy (EIS).
Abstract: Mn3O4 nanoparticles and graphene/Mn3O4 composites were synthesized by a facile method. The Mn3O4 nanoparticles were uniformly distributed on graphene nanosheets, which were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The capacitive properties of the Mn3O4, graphene and graphene/Mn3O4 composites have been investigated by galvanostatic charge/discharge, cyclic voltammetry (CV) and electrochemical impendence spectroscopy (EIS). The specific capacitance of Mn3O4 reached 190 F/g at a scan rate of 10 mV/s in 5 M KOH electrolyte., owing to pseudocapacitance. The G/Mn3O4 nanocomposites achieved a specific capacitance of 140 F/g (27.6% increases than that of graphene), a good rate property and good cycle stability, making them a promising electrode material as supercapacitors.
21 citations
TL;DR: An easy and sensitive nonenzymatic glucose sensor was fabricated based on CuO-ZnO composite nanofibers by electrospinning and subsequent thermal treatment that was optimized to obtain the best sensing properties.
Abstract: An easy and sensitive non-enzymatic glucose sensor was fabricated based on CuO-ZnO composite nanofibers by electrospinning and subsequent thermal treatment that was optimized to obtain the best sensing properties. The morphology and structure of the composite metal oxide were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The electrochemical and electrocatalytic properties of CuO-ZnO for glucose electro-oxidation were thoroughly investigated by cyclic voltammetry. In the amperometric detection of glucose under low applied potentials, the CuO-ZnO-modified Pt electrode exhibited an extraordinary detection limit of 0.126 μM, a wide dynamic range from 8.00 × 10−7 to 3.88 × 10−3 M, and excellent sensitivity of 463.7 μA/(mM·cm2). The CuO-ZnO/Pt electrode showed considerably higher electrocatalytic activity, excellent sensitivity, and fast amperometric sensing toward glucose oxidation. The sensor also showed good selectivity, long-term stability, and excellent reproduc...
TL;DR: In this article, the acicular wollastonite was prepared successfully using NaSiO3·9H2O and Ca(OH)2 as raw materials via two-step hydrothermal synthesis and calcination methods.
Abstract: The acicular wollastonite was prepared successfully using the NaSiO3·9H2O and Ca(OH)2 as raw materials via two-step hydrothermal synthesis and calcination methods. The scawtite and xonotlite were synthesized by two-step hydrothermal processes successively. The acicular wollastonite was prepared by the synthesized xonotlite after calcination. The hydrothermal-treated temperature, the water-solid ratio and the reaction time were studied for obtaining the xonotlite. The wollastonite powder was characterized by XRD, SEM and Differential Thermal Analysis. The results showed that the acicular wollastonite powder could be prepared efficiently after the hydrothermal treatment of 260°C for 2 hours with 6:1 water-solid ratio using the synthesized scawtite and calcination of the synthesized xonotlite by 800°C for 2 hours.
TL;DR: In this article, single-crystallined K0.5Na0.3 (KNN) nanorods were synthesized by hydrothermal process, and then parallel connected by a pair of interdigital Au/Ti electrodes, which were prepared on a flexible substrate by MEMS technique.
Abstract: The single-crystallined K0.5Na0.5NbO3 (KNN) nanorods were synthesized by hydrothermal process, and then parallel connected by a pair of interdigital Au/Ti electrodes, which were prepared on a flexible substrate by MEMS technique. After PDMS packaging and pre-polarization, the KNN nanorods exhibited high electromechanical conversion property with a stress-induced parallel output voltage up to several tens of millivolts. The voltage output of the KNN nanorods came from the back and forth electron transport in the external circuit driven by a forward piezoelectric potential and a reversed potential induced by the electron accumulation due to the Schottky contact, respectively.
TL;DR: In this article, a bilayer thin film humidity sensor based on graphene and polystyrene sulfonic sodium (NaPSS) has been presented, and their electrical and humidity sensing properties have been investigated in the range of relative humidity (11-95% RH).
Abstract: Bilayer thin film humidity sensors based on graphene and polystyrene sulfonic sodium (NaPSS) has been prepared, and their electrical and humidity sensing properties have been investigated in the range of relative humidity (11–95% RH). The results showed that the bilayer thin film humidity sensors exhibited lower impedance at very low humidity (11% RH), which was suitable for detection of low humidity. The graphene/NaPSS bilayer thin film sensors show over three orders of change and smaller hysteresis in the impedance verse the relative humidity variation from 11 to 95% RH. The humidity sensitive mechanism in the graphene/NaPSS bilayer thin film sensors is discussed.
TL;DR: In this paper, a series of Hf-doped ZnO nanocatalysts were synthesized by sol-gel method with a doping content up to 6 mol%.
Abstract: A series of Hf-doped ZnO nanocatalysts were synthesized by sol–gel method with a doping content up to 6 mol%. The structure, morphologies, and optical properties of the synthesized catalysts were characterized by XRD, TEM, FTIR and UV–Vis absorption spectrometer. The photocatalytic activity was evaluated by the Methylene Blue degradation in aqueous solution under sun light irradiation. Irradiation time and doping content had important effects on the photocatalytic activity of Hf-doped ZnO. Hafnium content had an optimum value of 2 mol% for achieving high photocatalytic activity. The experiments demonstrated that MB was effectively degraded up to 85% within 120 minutes. It was confirmed that the presence of Hafnium in ZnO catalysts could enhance the photocatalytic oxidation.
TL;DR: In this paper, the electrical properties and Raman spectroscopy of pure lead-free Na0.5Bi0.3 (NBT) and manganese-doped NBT single crystals were investigated.
Abstract: The electrical properties and Raman spectroscopy of [001]-oriented pure lead-free Na0.5Bi0.5TiO3 (NBT) and manganese-doped NBT single crystals have been investigated. With the effect of Mn-doping, the remnant polarization P r has a great enhancement from 15.2 μC/cm2 to 30.0 μC/cm2, and the pyroelectric coefficient is improved significantly from 178 μC/m2K to 241 μC/m2K. The Mn-doping has further altered the domain structure of the crystals, as revealed by piezoresponse force microscopy study. The Raman studies suggest that the substitution effect of Mn ions on B-site cations of the perovskite structure results in enhancement of the performance of the Mn-doped NBT single crystals.
TL;DR: In this article, a planar and volume constrained Perovskite model, which incorporates thermal expansion, has been utilized to determine ionic radii values, which provide significant improvements for more precise modeling of the lattice parameter of perovskites at room temperature as well as over extended temperature ranges.
Abstract: Materials LaAlO3 and A2+TiO3, where A is Ba, Ca, Pb and Sr, have been investigated in order to determine the “effective” temperature dependent ionic radii of 12-fold coordinated Ba2+, Ca2+, Pb2+, Sr2+ and La3+, and, 6-fold coordinated Al3+, Ti4+ and O2− within the “simple” “ideal” cubic Perovskite structure. The recently developed planar and volume constrained Perovskite model, which incorporates thermal expansion, has been utilized to determine ionic radii values. As compared with Goldschmidt based models, the newly determined radii provide significant improvements for more precise modeling of the lattice parameter of Perovskites at room temperature as well as over extended temperature ranges.
TL;DR: In this article, the phase change and modification of the anti-parallel spin structure by doping metals of Ho and Mn were investigated for enhancing the ferromagnetism of single-phase multiferroics.
Abstract: Polycrystalline BiFeO3 and Ho, Mn co-doped BiFeO3 nanoparticles were prepared using solution-gelation technology. The microstructures, phase structure, and magnetization were investigated for the nanoparticles. The analysis on x-ray diffraction indicates that the structure of nanoparticles transforms from hexahedron phase to tetragonal phase after doping metals of Ho and Mn. The ferromagnetism in Ho, Mn co-doped BiFeO3 nanoparticles is enhanced compared to the pure BiFeO3 nanoparticles. The enhancement is attributed to the phase change and modification of the anti-parallel spin structure by doping metals of Ho and Mn. The present work provides an available way on enhancing ferromagnetism of single-phase multiferroics.
TL;DR: In this paper, a surfactant-assisted precipitation method using cetyltrimethylammonium bromide (CTAB) and polyvinyl alcohol (PVA) as surfactants was used to synthesize CaWO4 microcrystallines.
Abstract: CaWO4 microcrystallines have been synthesized via a surfactant-assisted precipitation method using cetyltrimethylammonium bromide (CTAB) and /or Polyvinylalcohol (PVA) as surfactants, respectively. The as-prepared CaWO4 microcrystallines were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectra and photoluminescence spectra (FL). The growth process of these CaWO4 microcrystallines obtained in the presence of CTAB and PVA has been discussed. The structural characterization results indicate that the obtained CaWO4 are ellipsolid-like microcrystallines with the average size of ∼350 nm in short axis and ∼800 nm in long axis, and the CaWO4 microcrystallines possess a pure scheelite structure with a tetragonal symmetry. The FTIR spectra provide the evidence of W–O stretching vibration in [WO4]2− tetrahedrons at 796 cm−1 and W-O bending bands at 438 cm−1. FL spectra reveal that the CaWO4 microcrystallines exhibit the only green peak at 430 nm ex...
TL;DR: In this article, the microscopic mechanism of interactions on Gr/polypyrrole (Gr/PPy) interface is investigated, and the interaction configurations, intermolecular interaction energy and pair correlation functions between graphene and PPy are computed.
Abstract: Graphene receives world-wide attention due to its unique two-dimensional structure and exceptional electrical and mechanical properties. The graphene/polypyrrole (Gr/PPy) nanocomposites, have been synthesized via dispersing the graphene into polymers, which can be widely used in microwave absorption, supercapacitors and electronic devices. Molecular dynamics simulations are carried out to investigate the microscopic mechanism of interactions on Gr/PPy nanocomposites interface. The interaction configurations, intermolecular interaction energy and pair correlation functions between graphene and PPy are computed. The curves of temperature, energy evolution and interaction energy analysis indicate that Gr/PPy system reaches equilibrium in a relatively short time, and it is a thermodynamic equilibrium system. The interaction configurations show that there is an attractive interaction between the graphene and PPy. Pair correlation functions reveal that there are van der Waals interactions and hydrogen bond betw...
TL;DR: In this paper, the magnetic properties of ferrimagnetic glass-ceramics from a modified solid-state sintering method were studied for hyperthermia treatment of bone cancer and the results showed that the saturation magnetization (Ms), remanence (Mr), and coercivity (Hc) increased by the addition of SF in the bioglass.
Abstract: The magnetic bioglass-ceramics were introduced for hyperthermia treatment of bone cancer. The aim of this work was to study the magnetic properties of ferrimagnetic glass-ceramics from SrFe12O19(SF)-SiO2-CaO-Na2O-P2O5 system by using the modified solid-state sintering method. The results showed that sodium calcium silicate (Na4Ca4Si6O18), strontium iron oxide (SrFe12O19) and iron oxide (Fe2O3) were precipitated in all samples. The saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) increased by the addition of SF in the bioglass. The samples were soaked in simulated body fluid (SBF) for 14 days in order to investigate the bioactivity of the samples in vitro. The apatite layer was found on the surface of all bioglass-ceramics confirming their biocompatibility and it increased with increasing strontium ferrite content.
TL;DR: The results suggest that the SiO2 NPs have toxic effects on the development of zebrafish embryos and the effects could be resulted by oxidative damage.
Abstract: To assess the aquatic ecosystem safety of silicon dioxide (SiO2) nanoparticles (NPs), we studied the toxicity of the SiO2 NPs and SiO2 bulk particles (BPs) using zebrafish. Our results show that the SiO2 NPs can significantly affect the development of zebrafish embryos, while there is no obvious effect on survival and development of embryos was found in SiO2 BPs exposure group. The content of malondialdehyde (MDA) in zebrafish larvae exposed to the SiO2 NPs for 108 hours, increased significantly in dose-dependent manner. These results suggest that the SiO2 NPs have toxic effects on the development of zebrafish embryos and the effects could be resulted by oxidative damage.
TL;DR: In this article, the effects of MnO on the microstructure and electrical properties of Ba0.85Ca0.15Ti0.10O3 (BCTZ) ceramics were investigated.
Abstract: Effects of MnO on the microstructure and electrical properties of Ba0.85Ca0.15Ti0.90 Zr0.10O3 (BCTZ) ceramics were investigated. Its sintering temperature decreases, a phase boundary shifts to a higher temperature, and a denser microstructure is induced by introducing MnO. Double P-E loops were observed in BCTZ with x ≥ 0.30 wt% MnO due to the involvement of more defects. Piezoelectric properties are degraded by doping MnO, but the temperature stability of piezoelectric properties is improved with a low dielectric loss of ∼ 0.63%. As a result, BCTZ ceramics with x = 0.15 wt% MnO have optimum electrical properties: d 33 ∼ 382 pC/N, k p ∼ 44.5%, ϵ r ∼ 2611, and tan δ ∼ 0.63%.
TL;DR: In this paper, the results of the Raman study of lattice dynamics and local compositional fluctuations in cubic spinel Zn2TiO4 nanostructures are presented and attributed to local vibrational modes.
Abstract: We present here the results of the Raman study of lattice dynamics and local compositional fluctuations in cubic spinel Zn2TiO4 nanostructures. The observed Raman modes of the spinel structure are identified and attributed to local vibrational modes. Additionally, the analysis of the nonpolar E2(H) (∼437 cm−1, 54.2 meV) and A 1g (∼716 cm−1, 88.7 meV) modes are made and contributed to lattice deformation associated with the distinct coordination preferences of Zn and Ti.
TL;DR: In this article, an ultrasound sensitive and amplified piezoelectric immunosensor (PEI) was proposed for the detection of ultra-trace of Myoglobin (Mb) in human serum based on precipitation of an insoluble product on the functionalized gold electrode.
Abstract: An ultrasensitive and amplified piezoelectric immunosensor (PEI) with highly sensitivity has been proposed for the detection of ultra-trace of Myoglobin (Mb) in human serum based on precipitation of an insoluble product on the functionalized gold electrode. The core-shell Fe3O4@Au (with 85 nm as particle size)-multi-walled carbon nanotubes nanostructures labeling with Myoglobin first antibody (Mb Ab1) was firstly synthesized as capture probe(Fe3O4@Au-Mb Ab1-MWCNTs). It was modified on the surface of quartz crystal gold electrode. After a sandwich-type immunoreactions, the immunocomplex formed between Fe3O4@Au-Mb Ab1-MWCNTs/Mb and the HRP linked secondary antibody (HRP-Mb Ab2), can lead to the decrease of frequency (Δf) of the piezoelectric crystal electrode. Moreover, HRP enzyme labeled on the immunocomplex can catalyze 3- Amino-9-ethylcarbazole (AEC) in the presence of H2O2, resulting in an insoluble product on the electrode surface. The above two matters, immunocomplex and AEC's oxidation product, can a...
TL;DR: In this paper, the IEP of the γ-Al2O3/CeO2 coated nanoparticles is about 7.2, which displays a significant shift toward pure CeO2.
Abstract: γ-Al2O3 nanoparticles prepared through a chemical precipitation method were directly coated with CeO2 by means of a precipitation technique. X-ray diffraction (XRD), infrared (IR) spectra, transmission electron microscopy (TEM) and energy dispersive analysis of X-ray (EDAX) were used to characterize the γ-Al2O3/CeO2 coated nanoparticles. XRD patterns show that the composite nanoparticles are the cubic crystal γ-Al2O3 and the fluorite-structured CeO2. IR results indicate that the coating of the γ-Al2O3 nanoparticles with CeO2 evidently gives rise to the bands at 720 and 600 cm−1 whose vibration intensity becomes strong shift to lower wavenumbers. The IEP of the γ-Al2O3/CeO2 coated nanoparticles is about 7.2, which displays a significant shift toward pure CeO2. TEM micrographs reveal that γ-Al2O3/CeO2 coated nanoparticles show a spherical morphology with the diameter about 15 nm. Dispersion behaviors of γ-Al2O3/CeO2 coated nanoparticles under different conditions were studied in water suspension by investig...
TL;DR: In this paper, the optical properties of SiO2/Ti/SiO2 multilayer films with the different thickness individually are studied to meet the better optical requirement of a solar selective absorber layer.
Abstract: The solar selective absorber layer is the key part in the heat energy collector. In this study, optical properties of SiO2/Ti/SiO2 multilayer films with the different thickness individually are studied to meet the better optical requirement of a solar selective absorber layer. The variation of the optical reflctance due to the different thickness of individual layer is calculated. Based on the simulation results, a optimized thickness of multilayer, SiO2/Ti/SiO2/Si with the layer thickness of 90/7/110 nm, is obtained, the layer is then fabricated by sputtering deposition and its reflectance is measured for comparison with the result of calculation. The SiO2/Ti/SiO2 multilayer film could be used as a solar selective absorber layer, which is non-Cr-based film and with the good photothermal conversion efficiency of more than 95%. SiO2/Ti/SiO2 multilayer film with the layer thickness of 90/7/110 nm could be a new candidate material for the solar selective absorber layer.
TL;DR: In this article, the effects of BCZT addition on the dielectric and piezoelectric properties and the biocompatibility of the 45S5 composite were investigated.
Abstract: In this work, ferroelectric Ba0.92Ca0.08Zr0.05Ti0.95O3/45S5 bioglass composite or (BCZT/45S5 composite) has been produced for orthopedic applications. The BCZT concentrations ranged from 0–15 wt.%. The BCZT/45S5 composite was prepared by conventional melting method at 1300°C for 1 h following by heat treatment schedule at the crystallization temperatures of glass. The effects of BCZT addition on the dielectric and piezoelectric properties and the biocompatibility of BCZT/45S5 composites were investigated. It was found that, the addition of BCZT improved the hardness and dielectric properties of materials, which may be caused by the presence of the BCZT. Moreover, the bioactivity of the 45S5 bioglass was improved with addition of BCZT phase as evident by the formation of bone like apatite layers on the surface of all BCZT/45S5 composites after soaking in simulated body fluid (SBF).
TL;DR: In this paper, uncracked zirconia (ZrO2) monolithic aerogels were prepared using a sol-gel process accompanied by high temperature supercritical fluid drying technology.
Abstract: Uncracked zirconia (ZrO2) monolithic aerogels were prepared using a sol–gel process accompanied by high temperature supercritical fluid drying technology. Moreover, the experimental results on microstructure of ZrO2 aerogels modified by PO (propylene oxide) were reported. As more PO added to the starting solution, pH rose and the gel time decreased. SEM and N2 adsorption–desorption curves showed that the particle With the molar ratio of PO to Zr increasing from 0 to 2.5, size and connectivity of network of ZrO2 aerogels increased, while average pore radius increased from 6.6 nm to 15.1 nm then decreased to 8.5nm and pore volume increased from 1.2 cc/g to 1.87 cc/g then decreased to 1.44 cc/g.
TL;DR: In this paper, the authors characterized the structure of the cobalt-based Fischer-Tropsch (F-T) catalysts by X-ray diffraction, transmission electron microscope and energy-dispersive Xray spectroscopy.
Abstract: The cobalt–based Fischer–Tropsch (F–T) catalysts, in which Co3O4 nanocrystals, supported on TiO2 nanotubes were prepared and charactered. The structure of the catalysts was characterized by X–ray diffraction, Transmission electron microscope and energy–dispersive X–ray spectroscopy. And the catalytic activity in F–T reaction was also investigated. In the CO hydrogenation reaction, the cobalt species dispersed on the TiO2 nanotubes have higher selectivity and activity compare to sample in which Co3O4 nanocrystals supported on TiO2 bulk materials. According to the data of product selectivity, it can be concluded that cobalt–based F–T catalysts had higher selectivity and activity.