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Ferroelectric materials are promising for solar energy conversion due to the unique spontaneous polarization effect, leading to effective control of electron-hole recombination and potentially high power conversion efficiency of perovskite solar cells. Herein, the ultrathin ferroelectric hafnia alumina (HfAlO) films were obtained by atomic layer deposition and applied to modify the electron transport layer of PSCs. The XPS and AFM characterizations indicate that the Hf0.39Al0.10O films feature smooth, dense, and compact surface morphology. For the devices incorporating the ultrathin HfAlO films, the oriented ferroelectric effect-induced spontaneous polarization and internal electric field are crucial factors to enhance the charge separation during charge transfer. Accordingly, the short circuit current, open-circuit voltage, and power conversion efficiency (PCE) are increased by 11.8%, 9.0%, and 29.8%, respectively. Moreover, the HfAlO incorporating devices retained ~ 80% of the original PCE after 500 h ageing, much better than that of the pristine devices showing the retention of only ~ 50% of the original PCE.

6061 aluminium was treated by Plasma electrolytic oxidation (PEO) where a new experimental method was introduced: the applied voltage of the PEO process was quickly increased to 486 V by different ...

Various plasma electrolytic oxidation (PEO) ceramic coatings were fabricated on aluminum in the electrolytes with different concentrations of Na2SiO3·9H2O. The morphology of fractured cross-section and coating/substrate (C/S) interface, phase compositions, and corrosion behavior of these ceramic coatings were characterized employing field emission scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffractometer (XRD), potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The results showed that adding Na2SiO3·9H2O in the electrolyte could reduce the decrease amplitude of the voltage-time curve, and it can affect the types of the anodic film before the beginning of plasma discharges. A novel phenomenon was recorded as PEO treatment was carried out in the electrolyte with 1.85 g l−1 Na2SiO3·9H2O that the substrate was first covered by a barrier-type anodic film, and then a porous-type anodic film appeared after the barrier-type anodic film was broken down. The anodic film continued to grow for a long duration in the PEO process after being broken down. Characteristics of PEO ceramic coatings with a similar thickness acquired in various electrolytes were also evaluated. XRD results indicated that these ceramic coatings of similar thickness were mainly composed of α-Al2O3 and γ-Al2O3, and the α-Al2O3 proportion decreased with increasing Na2SiO3·9H2O concentration. The electrochemical data showed that the corrosion resistance of these PEO ceramic coatings of similar thickness decreased by adding Na2SiO3·9H2O in the electrolyte.

Plasma electrolytic oxidation (PEO) of Al was carried out in dilute alkaline sodium tripolyphosphate (Na5P3O10) electrolyte. Surface and cross-section morphologies, elemental and phase compositions were characterized by scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffractometer (XRD). The results revealed that a severe thinning of the anodic film resulted in the voltage decrease at the initial stage of the PEO process. Porous-type anodic film with uniform pore diameter were fabricated at the initial stage of PEO process. Subsequently, detachments and cracks took place on the anodic films, and served as weak regions occurring dielectric breakdown preferentially due to the concentration of electric current at these sites. Two origins of PEO coatings, the transformation of anodic films and the normal generation of PEO coatings through the plasma discharges, were proposed. The results also indicated that P element mainly participated in the anodic oxidation and existed as amorphous phase in the inner side areas of anodic films except the barrier layer. Based on the analyses of the microstructure evolution and the chemical composition, a schematic of coating growth mechanism was proposed in the end.

A plasma electrolytic oxidation (PEO) coating was fabricated on AA1060 alloy in an alkaline sodium hexametaphosphate ((NaPO3)6) electrolyte. The growth characteristic of the PEO coating was investigated by means of a substrate-detachment technique, Scanning electron microscope (SEM) equipped with energy dispersive spectrometry (EDS), X-ray photoelectron spectrometer (XPS), X-ray diffractometer (XRD) and Mott-Schottky analysis. The results showed that an ordered and porous anodic aluminum oxide (AAO) film was formed at the anodic oxidation stage by the influence of (NaPO3)6 in the electrolyte, and the microstructure of the AAO film induced the plasma discharge events to initiate inside the AAO film. The Mott-Schottky analysis showed that the PEO coated samples were all represented n-type semiconducting behavior. The microstructures of detached coatings showed that the coating/substrate interfaces formed at the anodic oxidation stage and sparking stage consist of numerous hemispherical cap structures, but with different sizes. It was also revealed that the inward growth of the hemispherical cap structures is dependent on the diffusion of oxygen from the electrolyte or plasma gases to substrate, and P atoms mainly exist in the amorphous phase of the PEO coating.

Plasma electrolytic oxidation (PEO) coatings were prepared on AA1060 alloy substrate by a galvanostatic regime in an alkaline sodium hexametaphosphate ((NaPO3)6) electrolyte, and the influences of ...

Plasma electrolytic oxidation (PEO) coatings were fabricated on the aluminum in silicate electrolyte. Microstructures and elemental compositions of these PEO coatings were examined by scanning electron microscopy (SEM) equipped with an energy-dispersive x-ray spectroscopy (EDS). Corrosion resistances of the coated samples were evaluated using the measurements of open-circuit potential (OCP), repetitive polarization and electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution. The results indicated that the PEO coatings not only act as a physical shield limiting the penetration of corrosive solution, but also establish an anodic location with high concentration of H+ ions and other product ions as pitting corrosion begins. With the development of pitting corrosion, the accumulation of corrosion products inside the pits and pores of the coatings decreases the corrosion process effectively.

Coatings prepared by different electrolyte additives were investigated on AZ31 magnesium alloy by plasma electrolytic oxidation. In this study, scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis were employed to assess the morphologies, chemical and phase compositions of the plasma electrolytic oxidation (PEO) coatings, respectively. Furthermore, electrochemical impedance spectroscopy was used to evaluate the corrosion behavior of the composite coating. The investigation of the effect of electrolyte additives in the base electrolyte showed that the PEO specimens exhibit different surface and cross-sectional morphologies, and phase compositions. The results showed that SiO32&minus, was conducive to the growth of the ceramic layer, and the ceramic layer developing in the electrolyte which contained AlO2&minus, showed a typical double-layer structure. The corrosion resistance of coating formed in a phosphate bath was higher than that of the coating formed in silicate bath and coating formed in an aluminate bath. Moreover, the corrosion resistance of the coating formed in the fluoride bath was the highest.

Novel graphene oxide on polystyrene microspheres were fabricated via layer-by-layer assembly and initially applied to extract four bisphenol endocrine disruptors (bisphenol A, bisphenol B, bisphenol AF, tetrabromobisphenol A) in various environmental water samples following high performance liquid chromatography-tandem mass spectrometry determination. The as-synthesized adsorbent was then applied for dispersive solid-phase extraction. The as-prepared GO@PS was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy. Furthermore, the main parameters governing the extraction efficiency were optimized in detail, and under the optimized conditions, attractive results were obtained. The developed method exhibited high enrichment factors ranging from 73 (BPB) to103 (BPA), low detection limits (0.02-0.11 μg·L-1) and wide linear ranges (0.1-1000 μg·L-1) for enriching and detecting the four bisphenol endocrine disruptors. Meanwhile, acceptable results were obtained when the developed technique was used to determine four target pollutants in real water samples, with spiked recoveries in the range of 71.1%-104.8%. This indicated that GO@PS was a powerful material for the enrichment and determination of bisphenols in complex matrices.

In the current investigation, plasma electrolytic oxidation (PEO) ceramic coatings on Al are galvanostatically synthesized at various processing stages in an alkaline silicate system. The resultant coatings are systematically surveyed in terms of the following respects: the applied voltage and surface sparking evolution over the studied course of PEO are recorded by the signal acquisition system and the real time imaging, respectively; the phase constitution, the surface morphology, polished cross section of the coated specimens, the fractured cross section and coating/substrate interface of the detached coatings are characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) assisted with energy-dispersive X-ray spectrometer (EDS), respectively. In particular, the coatings detached by an in-house developed electrochemical way disclose the coating microstructure in a new angle, which allows the cross section and the coating/substrate interface to come clearly into focus. The microstructure evolution of the oxide ceramic coatings and the correspondences among the characteristic microstructures of the free surface, the fractured cross section and the coating/substrate interface are presented and discussed. Further, based on the present PEO coating microstructure, a model of the coating growth that evolves over time is proposed.

A CuO-Al2O3 composite coating was obtained by an AC deposition and a followed secondary MAO treatment in an acidic copper sulfate electrolyte and an alkaline sodium hexametaphosphate electrolyte. Analyzes on phase and elemental composition and microstructure showed that a continuous CuO layer was formed on the top of the original MAO coating. EIS test suggested that after a secondary MAO treatment for 1 min, the samples obtained by AC deposition for 5 min had the best corrosion resistance, because of the barrier of CuO layer to the NaCl solution.

Micro-arc oxidation (MAO) coatings were prepared on Al substrate in alkaline sodium hexametaphosphate, sodium silicate and sodium aluminate electrolytes, the breakdown voltage and responsive current respectively decreased and increased with increasing the electrolyte concentration. The behavior of electrolyte during MAO processes was analyzed and discussed based on the data of the coating microstructure, elemental and phase composition, and the carrier density and impedance of the coating. The behavior can be explained by a mechanism in which anions incorporated into the coating reduced the anion vacancies, thus reducing the carrier density and improving the impedance.

Ceramic coatings were performed on aluminum through plasma electrolytic oxidation (PEO) in a Na5P3O10 solution with various concentrations of NaOH. It was revealed that the concentration of NaOH affected the types of anodic films and the activity of plasma discharges. Emphatic investigation was performed on the coatings fabricated in the electrolyte with addition of 1 g L−1 NaOH, focusing on the coating microstructure evolution and coating corrosion resistance. Some coatings were detached from the substrate, showing that the oxide particles on the anodic film C/S interface underwent profile variations from hemisphere to polygon, and its interpore distance decreased over time. The formations of pores of anodic films and plasma discharge of the PEO coatings were both easy to occur around the existing pores and the existing discharge channels. Fractured cross-section showed that a pancake-like structure corresponded to a discharge channel, a cavity, and a barrier layer protrusion whose area was similar to that of the corresponding pancake-like structure. The data of potentiodynamic polarization measurements showed that the sample treated with PEO for 10 min possessed the lowest icorr value of 4.97E-8 A cm−2, the most positive Epit value of −0.63 V, and the highest Rp value of 2.66E5 Ω cm2. EIS data of 10 min sample exhibited the highest R2 value of 1.61E6 Ω cm2, demonstrating the best corrosion resistance among these samples.

The factors that influence environmentally-friendly powder rubber powdering are introduced. Types and dosage of isolation agent, types and dosage of coagulant, environmental antioxidant, condensation temperature, stirring speed on the effect of powder rubber are examined. Thus a simple method to prepare environmental powder rubber is provided.As a physical variation of traditional bulk rubber, powder rubber can change the situations that high energy consumption and high labor intensity of the former. And it also can make the mixing process become continuous, automated, energy-saving and so on. In recent years, with the progress of rubber processing industry, the demand of powder rubber increases rapidly. And there is a intense requirement of supplying environmentally-friendly powder rubber[1-3]. So it is very important to do this experiment.

By examining the compressive and flexural strength of composite and using scanning electron microscopy (SEM), we analyzed the influence of sodium hydroxide on the properties of FGD gypsum and slag composite materials and discussed the influence of sodium hydroxide on the setting time and mechanical strength of the composite materials and presented the action mechanism of sodium hydroxide as a stimulator. The results show that when the content of sodium hydroxide was percent of 0.25, the maximal strength of FGD gypsum-slag composite materials was reached.

In this work, a general expression of the thermo-acoustic (TA) emission from nanocrystalline porous silicon (nc-PS) is derived by using a fully thermally-mechanically coupled multilayer TA model. This expression takes thermal, mechanical, and geometry properties of every layer in a multilayer structure, as well as the thermal contact resistances between layers into consideration and hence agrees well with the experimental results. Therefore, many fundamental problems in thermally induced ultrasonic emission from nanoporous silicon can be studied.

In an attempt to investigate the formation rule and corrosion resistance of the plasma electrolytic oxidation (PEO) coating on crevice surface of AZ31 magnesium alloy, the crevice coatings were fabricated on the samples of irregular shapes with different values of crevice width. The value of crevice width was varied from 200 to 350 μm for investigating the effect of crevice width on the surface and cross-sectional morphology, phase composition, corrosion resistance of crevice coatings. The results indicated that the crevice coating differs markedly in morphology and corrosion resistance when the value of crevice width reaches 350 μm, in spite of all coated samples have similar phase compositions. The effect of current density and ultrasound treatment on crevice coatings thickness were also studied systematically. Studies have shown that the increase of current density and the introduction of ultrasound treatment are both favorable for the crevice coatings.

Objective To compare the biomechanical properties of two lag screws proximal femoral nail(PFN) when they are placed in different points of the neck of femur in the treatment of intertrochanteric fracture of femur. Method Three pairs of fresh femora of adults aging from 55 to 65 are taken. They are made into AO type A1.1 intertrochanteric fracture. Fracture specimens are fixed by PFN. The mechanical testing machine loads the fracture model at a speed of 0.5mm/s. The stress distribution of the fracture broken ends, the opening angle of the fracture broken ends, and the relationship between load and displacement are recorded respectively. Result The stress change of the group inferior of the small trochanter is smaller than that of the group superior. The opening angle of the fracture of the group inferior is smaller than that of the group superior. The displacement of the top of the femoral head of the group inferior is smaller than that of the group superior. Conclusion The performance of the group inferior is better than that of the group superior. Thus it can be concluded that when two lag screws of PFN were placed in the middle and below 1/3 part of femoral neck, the biomechanical properties are better, the structure is relatively more stable, and the stress bearing is more reasonable.

Low-energy ion implantation is a new mutation source, which has the characteristic of light damage, high mutation rate, and a broad spectrum mutation. In order to obtain industrial strain with high L-(+)-lactic acid yield, the original strain Lactobacillus casei CICC6028 was mutated by nitrogen ion beam implantation. It was found that the original strain had a higher positive mutation rate when the output power was 10keV and the dose of N+ implantation was 50×2.6×1013 ions/cm2. The mutant N-2 was obtained for many times screening and its yield of L-(+)-lactic acid was 136 g/L which was improved by 38.8% compared with the original strain whose yield of L-(+)-lactic acid was 98g/L as the cultivation time was 120h. The initial screening methods were also studied in this work but it was found that the transparent halos method was unavailable, so the initial screening was performed by shake flask fermentation. HPLC chromatogram was used to analyse the purity of L-(+)-lactic acid that was produced by the mutant strain N-2, and the result indicated the main production of N-2 was L-(+)-lactic acid and there was no other acid almost.

In this paper, the ultrasonic infrared thermography (UIT) technique was applied to detect the composites damage. The frictional heating and thermal conductivity at the location of crack of the composites under ultrasonic excitation was simulated by finite element method (FEM). The excitation parameters including time, amplitude and frequency were studied. The composite involving delamination was detected by the ultrasonic generator. The results show that the UIT can identify the contacting interface-type damages at the surface or subsurface of composites rapidly, for example, delamination, fatigue crack et al.The excitation time, amplitude and frequency are impotent detection parameters. It can be seen accurately and intuitively of location of the damage, and there is no uniform heating problems from the experiment. Suitable coupling material can improve testing quality and eliminate “standing wave” effectively.

The paper studied on parameters of ion implantation into lipid producing strain Rhodotorula glutinis and lipid extration technology. It was found that the strain had a higher positive mutation rate when the output power was 10keV and the dose of N+ implantation was 80×2.6×1013 ions/cm2. Then a high-yield mutant strain D30 was obtained and it’s lipid yield which was 3.10 g/L increased by 33.05% than that of the original. Additionally, statistically-based experimental designs were applied for the optimization of lipid extraction by acid-heating coupling ultrasonic technique. By a Plackett-Burman design, it was found that three factors, treatment time of HCl (p=0.036) , ultrasonic time (p=0.0105) and rate of extracting solution (VCHCl3:VCH3OH) (p=0.0105), had significant effect on lipid extraction. Subsequently, these significant factors were optimized using response surface methodology (RSM), and the optimized parameters of lipid extraction were as follows: 34 min for treatment time of HCl, 7.5 min for ultrasonic treating time, 1.9:1 for rate of extracting solution (VCHCl3:VCH3OH). Finally the fermentation characteristic of high-yield mutation strain D30 was studied, when fermentation time was 10 d, it’s lipid yield increased to 7.81 g/L

With ion implantation, a high xylanase-producing strainAspergillus nigerBU99 was selected. Different late acting carbon sources (wheat bran, wheat straw, corncob and bagasse) had an effect on enzymatic production. Additionally, it was found that fast acting carbon sources (lactose, galactose, sucrose, glucose and maltose) put into the media affected on xylanase production too. Severe catabolic repression was observed in the media with lactose, but other sugars (galactose, sucrose, glucose and maltose) could increase the production of xylanase compared with the control. The production of xylanase was improved too when corncob flour was hydrolyzed by α-amylase, cellulase or/and glucoamylase. Additionally, it was found that the production of xylanase would be almost higher at 60h when the media contained glucose or were hydrolyzed by enzymes.

Cubic phase ZrO2 microspheres, with a homogeneously mesoporous microstructure and peanut-like nano-grains, were prepared by a novel spray reaction technique after calcination at 600-800 degrees C. A comparative investigation of calculated and TEM-observed sizes of peanut-like nano-grains in mesoporous cubic phase ZrO2 microspheres has been performed. It is shown that the calculated grain sizes are not quite in agreement with the values obtained by TEM studies. The calculated nano-grain sizes along with characterization by TEM allow evaluation of grain size, morphology, and the state of aggregation. (c) 2007 Elsevier Inc. All rights reserved.

Highly monodisperse submicron-sized silica spheres were synthesized by a chemical method, and single-crystal colloidal multilayers were prepared by a vertical deposition technique. Rare earth complex Tb(ACAC)3phen was in-filled in this structure to investigate the photonic bandgap effect on the spontaneous emission. The photon density of states in the photonic crystal was calculated numerically to investigate the origin of the abnormally enhanced photoluminescence in the photonic bandgap region. Our results are suggestive of a new way to probe the position of fluorescent molecules in such photonic bandgap materials.

An explicit dynamic Galerkin meshfree formulation under the updated Lagrangian framework is presented to simulate large deformation damage and failure process in geomaterials. The failure initiation and development are characterized by the pressure sensitive Drucker-Prager plasticity coupled with the isotropic energy-based damage theory. A stabilized conforming nodal integration based on non-local gradient smoothing is employed to improve the computational efficiency and to regularize the material instability arising from strain localization. The capability of the proposed methodology to model the evolution of dynamic failure in geomaterials is demonstrated through a numerical example.

A two-dimensional photonic crystal heterostructure with a large complete photonic bandgap is presented. It consists of two photonic crystals, whose dielectric configurations are reverse, with triangular lattice of circular columns. The structure retains the ease of fabrication while increasing the maximum quality factor of the gap 2–3 times after optimization. Photonic bandgap properties are calculated using a plane-wave method and the transmission spectra are obtained.

A two-dimensional photonic crystal heterostructure, which consists of two photonic crystals of a square lattice of circular columns with reverse dielectric configurations, is proposed. Photonic band gap properties are calculated using a plane-wave method and the transmission spectra are obtained. After optimization, the relative width of the complete band gap reached 13.8% based on the simple unit-cell shape and crystal lattice. The photonic crystal heterostructure opens up new ways of engineering photonic band gap materials and designing photonic crystal devices.

An important criterion for effective gene therapy is sufficient chromosomal integration activity. The Sleeping Beauty (SB) transposon system is a plasmid system allowing efficient insertion of transgenes into the host genome. However, such efficient insertion occurs only after the system is delivered to nuclei. Since transposons do not have the transducing abilities of viral vectors, efficient delivery of this system first into cells and then into cell nuclei is still a challenge. Here, a phage display technique using a major coat displayed phage library is employed to identify a peptide (VTAMEPGQ) that can home to rat mesenchymal stem cells (rMSCs). A nanoparticle, called liposome protamine/DNA lipoplex (LPD), is electrostatically assembled from cationic liposomes and an anionic complex of protamine, DNA and targeting peptides. Various peptides are enveloped inside the LPD to improve its targeting capability for rMSCs and nuclei. The rMSC-targeting peptide and nuclear localization signal (NLS) peptide can execute the synergetic effect to promote transfection action of LPD. The homing peptide directs the LPD to target the MSCs, whereas the NLS peptide directs transposon to accumulate into nuclei once LPD is internalized inside the cells, leading to increased gene expression. This suggests that rMSC-targeting peptide and NLS peptide within LPD can target to rMSCs and then guide transposon into nuclei. After entering the nuclei, SB transposon increase the insertion rates into cellular chromosomes. The targeting LPD does not show obvious cell toxicity and influence on the differentiation potential of rMSCs. Therefore, the integration of SB transposon and LPD system is a promising nonviral gene delivery vector in stem cell therapy.

An adhesive structure specimen, fabricated with several back-drilled flat holes of different size to simulate debond defects, was inspected by infrared thermography. Three larger defects could be seen directly by the raw images. However, two smaller defects could not be detected by the raw images because of high noise. The noise contributed by the variation of surface emissivity, was eliminated to some extent by coating the testing surface with uniform emissivity black paint in the experiment. It is found that the surface temperature changes with time satisfying exponential form. Therefore, a robust reducing noise method — exponential fitting of every pixel as a function of time, was presented to eliminate unwanted temporal noise in the raw images. Spatial noise was reduced by the combination some standard filtering algorithms e.g. average filtering with high-pass filtering, which made the invisible defect be detected. Finally, image segmentation algorithms based on watershed and 3D tomogram were used to visualize the defects, and defect's parameters were also estimated by the image after segmentation. The results show that the methods used in this work could improve defect detectability and achieve defect quantitative identification.