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Antibacterial and osteogenic functionalization of titanium (Ti) implants will greatly expand their clinical indications in immediate implant therapy, accelerate osteointegration, and enhance long-term prognosis. We had recently shown that the high-energy shot peening (HESP)-assisted micro-arc oxidation (MAO) significantly improved the bioactivity and coating stability of Ti-based substrates. In this study, we further functionalized Ti with antibacterial and osteogenic properties by doping silicon (Si) and/or copper (Cu) ions into HESP/MAO-treated coatings. Physicochemical characterization displayed that the doping of Si and Cu in HESP/MAO-treated coatings (Si/Cu-MAO) did not significantly change their surface topography, roughness, crystal structure, coating thickness, bonding strength, and wettability. The results of X-ray photoelectron spectroscopy (XPS) showed that Si and Cu in the Si/Cu-MAO coating was in the form of silicate radical (SiO32–) and bivalent copper (Cu2+), respectively. The total amounts of Si and Cu were about 13.5 and 5.8 μg/cm2, which released about 33.2 and 31.3% within 14 day, respectively. Compared with the control group (MAO), Si doping samples (MAO-Si) significantly increased the cell viability, alkaline phosphatase (ALP) activity, mineralization and osteogenic genes (ALP, collagen I and osteocalcin) expression of MC3T3-E1 cells. Furthermore, the addition of Cu presented good bactericidal property against both Staphylococcus aureus and Streptococcus mutans (even under the co-culture condition of bacteria and MC3T3-E1 cells): the bacteriostatic rate of both bacteria was over 95%. In conclusion, the novel bioactive Si/Cu-MAO coating with antibacterial and osteogenic properties is a promising functionalization method for orthopedic and dental implants, especially in the immediate implant treatment with an infected socket.

The segmented model test is often used to study the wave load characteristics of large ships as it can account for the hydroealstic effect. The vertical bending moment (VBM) is of crucial importance in ensuring the safety of ocean-going vessels in rough seas, and there exists in the literature a large number of experimental studies of the VBM. For ships with large openings in the deck, for instance, container ships, the lateral wave loads, such as horizontal bending moment (HBM) and torsional moment (TM) in quartering seas, are as important as VBM. There are, however, few studies on the measurement of the coupled horizontal-torsional vibrations of such ships in model tests. In the paper, a method is proposed for designing flexible backbone models that satisfy the similarities of vertical and horizontal bending stiffness as well as the torsional stiffness, and the measurement of the wave load components is also described. In order to meet the similarity of the hull girder stiffness, the backbone cross-section of a complex form is designed. Finite element method (FEM) is used to calculate the natural frequencies and mode shapes of the segmented model. Measurement of the vertical bending moment, horizontal bending moment and torsional moment are calibrated by applying various combinations of loads.

Aligned zinc oxide/zinc sulfide core–shell nanowire arrays are synthesized on transparent conductive oxide (TCO) glass substrate by sulfurizing ZnO nanowires using a vapor phase method. The length of these nanowires is about 7.3 μm with diameter of ~100 nm. The thickness of the ZnS shell can be controlled by adjusting the reaction time. It is found that the shell layer is well crystallized with preferring growth direction of ZnS [002]. The result indicates that when used to decompose methyl orange (MO), the core–shell nanowire arrays have superior photocatalytic performance under UV-light irradiation, which shows considerable potential applications of this nanocomposite in water purification.

The flashover at the solid-liquid interface is the main dielectric failure in the cryogenic insulation system, which has great relation with the carrier mobility. In this paper, epoxy$/\mathrm {B}\mathrm {N}$(boron nitride)/Graphene composites with different contents were prepared and the surface potential decay (SPD) method was employed to analyze the transit time and the carrier mobility. The experimental results indicate that the behaviors of surface potential and carrier mobility are affected by specimen temperature. Obtained results show that BN and Graphene particles can affect the carrier mobility and modulate the discharge speed, which may further influence the flashover voltage at solid-liquid interface at cryogenic temperature.

Cable accessories made of ethylene-propylene-diene terpolymer (EPDM) are considered to be the weakest part of HVDC cable system due to the existence of the interface between cable insulation and itself. The charges are likely to accumulate at the interface between insulation materials with different conductivity and permittivity, which may induce the occurrence of partial discharge and breakdown. Nanoparticles can be applied to adjust the interface charge behaviors. In this paper, carbon black (CB) nanoparticles were dispersed into EPDM with 0, 0.5, 1, 3 and 5 wt% respectively. The effects of nanoparticle doping on the interface charge distribution of LDPE and EPDM composite insulation were measured under −15 kV/mm. Furthermore, dielectric properties and DC conduction were introduced to discuss the suppression mechanism of carbon black nanoparticle doping. Obtained results the interface charge density can be suppressed to 0.5 C/m3 with 1 wt% carbon black nanoparticle doping, much less than the undoped and other doped groups. The mechanism of interface charge suppression is attributed to the decrease of conduction and permittivity mismatch by carbon black nanoparticle doping, which was proved by the dielectric spectroscopy and conduction current tests. The interface charge buildup depends on the time constant controlled by the doping proportion.

Moisture in oil-immersed transformer will become small bubbles suspending in insulation oil at high temperature. In order to investigate the influence of suspending bubbles on tracking failure of oil-impregnated pressboard in oil-paper insulation, a model based on needle-plate electrodes was established. This model was used to study effect of the number of suspending bubbles generated by dropped distilled water on the discharge voltage, how the discharge signals varied during the process of tracking failure on the oil-impregnated pressboard surface with the effect of suspending bubbles, and the surface carbonization process of oil-impregnated pressboard during tracking failure. The results show that when the number of suspending bubbles increases with the increase of dropped distilled water, the partial discharge inception voltage in oilpaper insulation descends slowly while the surface flashover inception voltage descends sharply. The discharge process can be divided into three periods orderly according to the discharge signals during tracking failure. The discharge signals in each period have some relationship with each other and the recurrence plot (RP) method is used to analyze characteristics of the discharge signals. The surface carbonization process can be also divided into three periods the same as the discharge process. The carbonization on the oil-pressboard surface is slow under partial discharge while it's fast under surface flashover. Because suspending bubbles make surface flashover much easier, so they make the tracking failure of the oil-impregnated pressboard much easier too, although the carbonization in the insulation oil is more difficult than that in the air. This paper is helpful to understand the process of tracking failure of oil-impregnated pressboard in insulation oil with the effect of suspending bubbles, which will be beneficial for the insulation protection in oil-immersed transformer.

PbSe quantum dot light emitting diodes (QD-LEDs) of a multi-layer architecture are reported in the present work to exhibit high external quantum efficiencies. In these devices, a ligand replacement technique was employed to activate PbSe QDs, and ZnO nanoparticles were used for the electron transport layer. The emission wavelength of this solution processed device is QD size tunable over a broad spectral range, and an LED efficiency of 0.73% was measured at 1412 nm. Higher efficiencies at longer wavelengths are also inferred from spectral characterization.

With the advantages of clean, renewable and wide distribution, wind power generation becomes an important part of the smart grid. Wind generator is the key apparatus in application of wind energy, which has been paid great attention to its operation reliability. Partial discharge in the insulation system is a serious threat to its safe operation. Polyimide (PI) has been widely applied as one of the most important organic materials owing to its excellent physical and chemical properties. And nano particals are incorporated in polyimide to enhance the properties, such as breakdown characteristics. In this paper, polyimide/Al 2 O 3 (PI/Al 2 O 3 ) nanocomposite films were prepared using in-situ dispersion polymerization process. The mechanical and electrical characteristics of the PI/Al 2 O 3 nanocomposite films with different alumina content comparing to the unfilled polyimide film, including the tensile strength and elongation, dielectric spectroscopy, dielectric breakdown strength and the corona resistance property as well, were studied.

We presented in this paper a photoassisted ligand exchange approach whereby light will be introduced to facilitate the replacement of oleic acid (OA) ligand molecules over PbSe quantum dots (QDs). The ligand-exchanged QDs were used to fabricate quantum dot light-emitting-diodes (QD-LEDs), which outperform the devices comprising the QDs without ligand-replacement.

The degradation mechanism of CdSe/ZnS quantum dots (QDs) light-emitting diodes (LEDs) was investigated with steady-state and time-resolved photoluminescence measurements. Our study reveals that the degradation is associated with the decreasing quantum efficiency of the CdSe/ZnS QDs in the devices. Two mechanisms that cause the efficiency reduction were verified in the experiments: i.e., thermal instability and luminescence quenching.

We presented in this paper a photo-assisted ligand exchange approach whereby light will be introduced to facilitate the replacement of oleic acid (OA) ligand molecules over PbSe quantum dots (QDs). The ligand-exchanged QDs were used to fabricate quantum dot light-emitting-diodes (QD-LEDs), which outperform the devices comprising the QDs without ligand-replacement.

We report a high-performance colloidal quantum dot (CQD)-based near-infrared tandem photodetector fabricated on flexible substrates via solution-processed method. The tandem photodetector on poly(ethylene terephthalate) substrates exhibited low dark current and high detectivities over ∼8.8 × 1011 Jones at near infrared range at −0.5 V bias and over ∼1013 Jones near 0 bias. The critical bend radii of ∼8 mm and ∼3 mm have been demonstrated for tensile and compressive bending, respectively. The performance of photodetectors remains stable under mechanical stress, making PbSe CQD material a promise candidate for flexible infrared sensing applications.

This study investigates the feasibility of loading nanostructured lasing medium and magnetic nanocrystals in the same microbead for potential applications in bio- and chemical sensing. A sequential infiltration process is proposed and tested for the preparation of magnetic and lasing microbeads by incorporating, respectively, iron oxide nanocrystals in the inner cores and colloidal quantum dots (CQDs) in the periphery regions of mesoporous silica microbeads. The co-doped bead structure was confirmed by electron microscopy and energy dispersive spectroscopy. The lasing action of the CQD gain medium in the mesoporous beads was characterized with micro-photoluminescence, revealing sharp whispering gallery mode lasing signatures, whereas the distinguishing superparamagnetic property was measured from the co-doped microbeads with vibrating sample magnetometry.

Tunnel junctions composed of two ferromagnetic electrodes separated by a ferroelectric barrier were fabricated from epitaxial La0.7Sr0.3MnO3/Ba0.95Sr0.05TiO3/La0.7Sr0.3MnO3 trilayers. Typical R−H curves with sharp-switched resistance states (magnetic parallel and antiparallel) of magnetic tunnel junctions have been observed up to room temperature. After applying a poling voltage, which reverses the barrier polarization, both the parallel and antiparallel resistance states will switch to different values. Clear tunneling magnetoresistance and tunneling electroresistance, hence the four resistance states have been observed at room temperature.