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The absorption properties of wave-absorbing coatings can easily fail; therefore, a layer of corrosion-resistant topcoat is often added to the surface to increase the service life of the absorbing coating. In this study, we compare the changes in samples without or with a topcoat, namely fluorinated polyurethane, at 25 °C with a NaCl solution and at 35 °C with a neutral salt spray. Morphological characterization and composition analysis show that the topcoat can indeed greatly improve the corrosion resistance of the samples, but the absorption of the coatings still decreases in a short time. The reasons for this are indicated by electrochemical impedance spectroscopy. For the samples without a topcoat, the corrosion of the wave-absorbing coatings results in the failure of wave absorption. For the samples with a topcoat, it is likely that the state of the interface between the topcoat and absorbing coatings leads to the decline of the resistance of the wave-absorbing coatings, causing them to fail quickly.

Light-driven polymerization, such as photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization, enables biological benign conditions and versatile functional polymer structure design, which is readily used in protein-polymer bioconjugates. However, conventional metalloporphyrinic homogeneous catalysts for PET-RAFT polymerization suffer from limited aqueous solubility and tedious purification. Here we demonstrate the design of PET-RAFT photocatalyst from the reticular assembled Zr-porphyrinic metal-organic frameworks (MOFs), along with a biomacromolecule-based chain transfer agent, as efficient bioconjugation tools in water. Our methodology offers manufacturing advantages on bioconjugates under mild conditions such that MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) and cytotoxicity assays have shown the preservation of the protein integrity, bioactivity, and high cell viability after PET-RAFT polymerization. We find that the fast kinetics are benefiting from the ultrahigh loading of metalloporphyrins in MOF-525-Zn. This heterogeneous catalyst also allows us to maintain living characteristics to incorporate myriads of monomers into block copolymers. Other advantages like easy postreaction purification, reusability, and high oxygen tolerance even in an open system are demonstrated. This study provides a tool of highly efficient heterogeneous photocatalysts for polymer-protein bioconjugation in aqueous media and paves the road for biological applications.

The adhesion force between individual human hair fibers in a crosshair geometry was measured by observing their natural bending and adhesive jumps out of contact, using optical video microscopy. The hair fibers' natural elastic responses, calibrated by measuring their natural resonant frequencies, were used to measure the forces. Using a custom-designed, automated apparatus to measure thousands of individual hair-hair contacts along millimeter length scales of hair, it was found that a broad, yet characteristic, spatially variant distribution in adhesion force is measured on the 1 to 1000 nN scale for both clean and conditioner-treated hair fibers. Comparison between the measured adhesion forces and adhesion forces modeled from the hairs' surface topography (measured using confocal laser profilometry) shows they have a good order-of-magnitude agreement and have similar breadth and shape. The agreement between the measurements and the model suggests, perhaps unsurprisingly, that hair-hair adhesion is governed, to a first approximation, by the unique surface structure of the hairs' cuticles and, therefore, the large distribution in local mean curvature at the various individual contact points along the hairs' lengths. We posit that haircare products could best control the surface properties (or at least the adhesive properties) between hairs by directly modifying the hair surface microstructure.

Aiming at the LED (Light Emitting Diode) point sources with Lambertian distribution, we propose an improved mesh method to design a free form lens. For this method, a free-form surface is divided into two parts. A part is designed to be a refraction surface by using mesh method. Based on the refraction, the other part is designed to be a reflection surface. The combination of two parts forms a free-form surface lens. To take a petal-shaped lens as an example, simulation results show that the lens designed by using the improved mesh method can be higher illumination uniformity by comparing our method with the tradition method. When the radius of the light shape increases, the illumination uniformity increases, but the efficiency has no obvious change. When the distance between the point light source and the target plane increases, the illumination uniformity does not change significantly and the efficiency increases. Thus, the improved method can realize the limited illumination of light shape in the far and near field, so it will has broad application prospects in LED lighting.

The nanosecond pulsed plasma discharge actuator is used on a flying wing aircraft. At the angles of attack rang from -4° to 28°, the impact of plasma actuator arrangement position and discharge frequency on lift-enhancement effect is tested. Oil flow visualization is used to investigate the surface flow pattern varies with angles of attack for the plasma actuator turned on and off. The result indicates that lift-enhancement can be achieved through the actuator discharges at large angles of attack on flying wing aircraft. The arrangement position and discharge frequency both have a significant impact on lift-enhancement effect. The actuator which arranged at the leading edge of the aircraft could get the best lift-enhancement effect. There exists an optimal discharge frequency, flow separation under this frequency can be effectively suppressed, which results the best lift-enhancement effect. The flow visualization test shows that the control mechanisms of the plasma actuator are to inject energy to the shear layer, thus increased the vortex strength. The vortices strengthen the mixing of the outer high-speed fluid with inner low-speed fluid, which effectively restrains the separation.

Membrane distillation (MD) is a membrane-based thermal separation process. Vapor pressure difference between both sides of the membrane is the driving force for mass transfer of volatile compounds via the gas phase. A hydrophobic porous membrane is generally used as a barrier to isolate the feed from the volatiles permeated across the membrane. Although MD is a thermally energy-intensive process, it can be coupled with low-grade/waste heat sources to increase the overall thermal energy utilization efficiency or reduce thermal pollution. In this chapter, five aspects of MD were studied: • Configurations of MD and their applications in wastewater and water treatment • MD performance enhancement and employment scope broadening by membrane material and structure modifications • MD commercialization • Treatment cost analysis • Conclusion and future trends

Multi-field coupling simulation method based on the physical principles is used to simulate the discharge characteristics of nanosecond pulsed plasma synthetic jet actuator. Considering the effect of the energy transferring for air, the flow characteristics of nanosecond pulsed plasma synthetic jet actuator are simulated. The elastic heating sources and ion joule heating sources are the two main sources of energy. Through the collisions, the energy of ions is transferred to the neutral gas quickly. The flow characteristics of a series of blast waves and the synthetic jet which erupt from the plasma synthetic jet (PSJ) actuator are simulated. The blast wave not only promotes outward, but also accelerates the gas mixing the inhaled gas from the outside cavity with the residual gas inside the cavity. The performances of PSJ actuator fluctuate in the first three incentive cycles and become stable after that.

The surface dielectric barrier discharge plasma actuator driven by nanosecond pulses is recognized as an effective fluid actuator for flow separation control. The operation condition of nanosecond dielectric barrier discharge actuators for separated flow control still requires further study, particularly prioritizing the improvement of the effectiveness and reducing energy consumption in flow separation control implementation. In this study, experiments are conducted using a two-dimensional NASA SC(2)-0712 airfoil in a wind tunnel with a Reynolds number of 0.5 × 106 (25 m/s). The pressure measurement experiments show that the location of actuators affects the efficiency of separation control. Particle image velocimetry results indicate that the most efficient location of the actuator is upstream of the separation point and near the original point of the separated shear layer. Meanwhile, the particle image velocimetry results show the vorticity attaches to the airfoil wall after discharge, which suggests that the reattachment is due to the generation of large-scale vortices. These present structures result in the mixing of the shear layer with the main flow thereby delaying separation and reattaching a separated flow. This study shows the most efficient location related to the separation point. Furthermore, it indicates the reattachment of flow is attributed to the motion of vortexes coherent structure.

The method of symmetrical spanwise blowing was used to suppress the wing-body rock of a typical canard-configuration model in free-to-roll tests. The experimental results showed that the rock was successfully suppressed by symmetrical spanwise blowing when the pitch angle was between thirty degrees and thirty-four degrees. However, this kind of blowing failed to suppress the non-commanded motion once pitch angle exceeded thirty-four degrees. To analyze the mechanism under this phenomenon, surface-pressure measurements and PIV tests were carried out. The reason for the successful suppression was inferred as the success of the delaying of windward vortex breakdown at a small sideslip angle, while the failed results at larger pitch angles were due to the fact that the blowing cannot delay the windward breakdown anymore under very small sideslip.

Controlled orientation and alignment of rod‐shaped plasmonic nanoparticles are of great interest for many applications. Herein, it is demonstrated that the nonlinear optical response of gold nanorod suspensions is dynamically controlled by electric field‐induced orientation. Merely by switching incident light polarization, the longitudinal and transverse surface plasmon resonance (SPR) absorption peaks are modulated with opposite trends, and the resulting optical nonlinearity is revealed from self‐trapping of plasmonic resonant solitons. Moreover, even with a very low concentration of fluorescent molecules, a significant increase in the fluorescent signal is observed with a transmittance‐type volume detection scheme. Such an enhancement is attributed to a combined action of optical force‐induced nonlinearity and electric field‐induced nanorod orientation, as explained by the theoretical analyses. Herein, new possibilities for engineering nonlinear plasmonic soft matter and detecting low‐concentration (yet a large total number of moleculesas needed) fluorescent samples are brought out.

In order to further study the inner characteristics of the plasma synthetic jet actuator (PSJA) which consists of a cavity, two electrodes and a lid with orifice, a two-dimensional numerical simulation is carried out with SST k-ω turbulence model. The evolutions of the flow parameters inside the cavity with a single pulse, such as pressure, density, temperature and velocity, are analyzed in detail. The oscillation mechanisms of the flow parameters at the orifice of the cavity is also investigated. To study the effects of geometric factors on the performance of the PSJA, five widths and heights of the cavities are considered. The results suggest that the base frequencies are inversely proportional to the width and height of the cavity respectively. The proportional constant is equal to the sound speed. Besides, shortening the width or height of the cavity can obtain a faster peak velocity of the jet. The peak of the jet velocity occurs earlier with a shorter height of the cavity.

Next-generation aircraft and missile are required to have extreme maneuverability, which should maintain stability at high angle of attack. However, the unsteady flow field surrounding the air vehicle would affect the aerodynamics loads and induce unwanted nonlinear motions, of which the rolling motions are usually generated. In order to investigate the unsteady rolling characteristics of a cruciform-finned slender body, the free-to-roll and force measurement tests including particle image velocimetry measurement have been conducted comprehensively. Different types of rolling motion, trimming at equilibrium positions, self-excited rolling oscillation, and self-excited spinning are observed during the free-to-roll experiment depending on the different angles of attack. The force measurement results show that the rolling motions are related to both the static and dynamic stabilities of the rolling moment at balance points. The stabilities of the rolling moment would change as the angle of attack for the model increases. At last, the flow field results from particle image velocimetry measurement indicate that the unsteady rolling motions may be induced by the interaction between the asymmetry vortices and strake wings, fins.

The basic dynamic characteristic of a nanosecond (NS) pulse discharge actuator in still air is investigated, which introduces viscid and inviscid effects to the flow, namely, heated air and pressure waves, respectively. The efficacy of a dielectric barrier discharge plasma actuator driven by a nanosecond pulse for active flow separation control is investigated experimentally on a NASA SC(2)-0712 aerofoil at Re = 0.5 × 10 6 (25 m/s). The pressure distribution on the aerofoil surface is measured, and the result indicates that the separation is well controlled at a high angle of attack. The PIV test result shows that the forcing frequency selectively affects the flow over the aerofoil, and a higher forcing frequency has a better influence on the leading edge shear layer. Schlieren imaging experiments at Re = 0.1 × 10 6 (5 m/s) show that the main disturbance factor for the nanosecond pulse plasma actuator is the heating effect, which changes the local temperature and density and induces several vortex structures. The vortex structures entrain the outer high-momentum fluid into the shear layer, thereby strengthening the mixing of the shear layer with the main flow and delaying separation or even reattaching a separated flow. The research reveals the major disturbance factor introduced by NS discharge applied to flow separation control. Furthermore, the spatiotemporal disturbance process induced by the pulse discharge is investigated.

Controlling the morphology of nanostructured materials is critical for their use in technological applications including in sensing, electronics and energy harvesting. In this paper we investigate the reaction pathways involved and their dependence on reactant concentrations in the formation of ZnO nanomaterials on –COOH terminated self-assembled monolayers using a simple chemical bath deposition process which employs zinc acetate, which acts as the Zn source, and ethylenediamine, which acts as both the O source and a complexing agent for Zn2 +. At a deposition temperature of 318 K (45 °C) our data shows that the concentration of Zn2 + as well as the deposition bath pH, which is controlled by the ethylenediamine concentration, is critical in determining the ZnO morphology. Above 0.01 M zinc acetate at low bath pH (~ 7.7–8.5), nanorods and nanorockets are observed to form. The nanorods exhibit a clear interface in the middle indicating that they are composed of two crystals. At lower zinc acetate concentrations over a wide pH range (~ 8.0–10.5) nanoflowers form. The nanorockets and nanoflowers grow via a modified La Mer mechanism in which there are multiple nucleation and crystallization steps. The initial nuclei are sphelurites (nanoflowers) or nanocrystallites (nanorockets). Since the reagent concentrations limit the reaction, for these initial precursor crystallites to increase in size, it is required dissolution and re-precipitation must occur. Thus at later times nanorockets or nanoflowers develop.

Fatigue is one of the most common yet complicated failures that can cause damage to mechanical structures. Structural adhesively bonded joints are not exempt from this deleterious phenomenon and have to be assessed under vibration loads. In this work, fatigue characteristics of single-lap joints (SLJ) made of steel and carbon fibre reinforced plastic (CFRP) laminates under vibration loads are primarily investigated by experiments. The aim of this work is to analyze the changes in the ultimate load of the SLJ under vibration loads. The experimental results showed that SLJ will face cohesive failure after the uniaxial tensile loading test. In addition to the increase of vibration cycles, the ultimate load and failure displacement gradually decrease. In order to model the adhesive between joint components and simulate the damage propagation, a new traction–separation law called the embedded process zone (EPZ) and a damage factor are introduced and developed within the framework of cohesive zone Model...

In this study, we investigated the effects of surface sliding discharge of a dielectric barrier discharge (SL-DBD) plasma actuator on the boundary layer flow using the time-resolved particle image velocimetry (PIV) technique. According to the PIV measurements, the peak-shaped mean jet flow is induced by the SL-DBD plasma actuator in quiescent air. Under the freestream of U∞ = 6 m/s on the flat plate, the results show that the streamwise velocity fluctuation induced by SL-DBD plasma is increased pronouncedly at the downstream of the actuator. Meanwhile, the mean flow velocity increases obviously in the downstream of the actuator. The instantaneous results show the formation of the vorticity at the bottom of the boundary layer after the plasma excitation. In addition, the vorticity has the behavior to lift up, possibly because of the induced peak-shaped jet.

A common capping agent for gold nanorods, Cetyl trimethylammonium bromide (CTAB), is particularly problematic for biological studies because of its cytotoxicity. Several procedures have been developed to remove the CTAB from the surface of the gold nanorods, but most are lengthy, involving many steps, and use expensive reagents. Here, we present a simple, one-pot method for the complete removal of CTAB from the surface of gold nanorods, so that particles can be more effectively utilized in biological in vivo studies. The procedure involves first adding sodium borohydride to remove the CTAB, quickly followed by a replacement ligand, such as mercaptoundecanoic acid (MUA). Both the CTAB removal and MUA replacement were monitored by FTIR, surface enhanced Raman spectroscopy (SERS) and X-Ray Photoelectron Spectroscopy (XPS) and compared to commercially available citrate-capped gold nanorods. The procedure presented herein is shown to be as effective at removing CTAB and replacing it with MUA as commercially available gold nanorod samples.

The room temperature atomic layer-like deposition (ALLD) of ZnO using diethylzinc (DEZ) and water precursors has been investigated on −COOH, −OH, and −CH3 terminated self-assembled monolayers. The detailed reaction pathways of ZnO ALLD on −COOH and −OH terminated SAMs are different. As expected on −OH terminated SAMs, the DEZ reacts with the hydroxyl group. However, on −COOH terminated SAMs DEZ reacts with both the carbonyl and hydroxyl bonds present and can lead to the formation of a ketone rather than ZnO deposition. The growth rates on these SAMs are different; after the first ALLD cycle the measured growth rates are 3.0 ± 0.1 and 3.4 ± 0.2 A/cycle on −COOH and −OH terminated SAMs, respectively. XPS analyses show that the initial composition of the deposited layer on −COOH terminated SAMs is similar to Zn(OH)2. After five ALLD cycles the −COOH terminated SAM is completely covered, and XPS analyses indicate that the deposited film is composed of ZnO. In contrast on −OH terminated SAMs, the deposited fil...

We report the fabrication of 2D ZnIn2S4 nanosheet/1D TiO2 nanorod heterojunction arrays by a facile hydrothermal process and their use as photoelectrodes in a photoelectrochemical (PEC) cell for high-performance solar water splitting. The morphology, microstructure, and phase of pristine TiO2 and 2D ZnIn2S4 nanosheet/1D TiO2 nanorod heterojunction arrays were characterized in detail. PEC measurements showed that 2D/1D heterojunction arrays offered enhanced photocurrent density (3 times higher than that of pristine TiO2), negatively shifted onset potential from 0.05 to -0.53 V, and high light on/off cycle stability. Electrochemical impedance investigation attested to a significant improvement of the interface electron transfer kinetics in this heterojunction, thus facilitating electron-hole separation, transfer, and collection, which resulted in enhanced PEC properties.

Sliding discharge, as a new type of electrical discharge, is being gradually applied in plasma active flow control in recent years. In this work, the particle image velocimetry (PIV) experiments were conducted to investigate the airflow characteristics induced by the sliding discharge plasma actuator at varied voltage signals. The results show that the integral thrust produced by the negative alternating current (AC) power is stronger than normal AC power under the same voltage magnitude. The induced airflow direction changes along with the changing of two power voltage signals. Furthermore, the angle of the induced airflow is mainly linear with the loading voltage.

Detailed phase-lock schlieren measurement was conducted to study the physical evolution process of the structures inside the plasma synthetic jet actuator driven by a high voltage nanosecond pulse. One strong blast wave and heat source core are generated immediately after the arcing discharge. Within the cavity, as the blast wave is reflected by the cavity walls and interacts with the heat source core, the pressure of the gas inside the cavity is increased rapidly and a series of diffractive wave comes out from the orifice of the cavity, followed by a train of vortex rings and a high speed jet.

We have investigated the selective photoactivated room temperature chemical vapor deposition (CVD) of aluminum (Al) on functionalized self-assembled monolayers adsorbed on Au. The CVD precursor employed is trimethyl aluminum (TMA). Using a deuterium arc lamp we demonstrate that the rate of the Al film growth is approximately twice that observed for nonphotoactivated Al chemical vapor deposition (CVD) using TMA. At the wavelengths employed, the photolysis of TMA leads to the dissociation of the TMA dimer to its monomer followed by successive release of methyl groups to form (CH(3))(3-x)Al. The photogenerated (CH(3))(3-x)Al species react with -OH- and -COOH-terminated SAMs but not -CH(3)-terminated SAMs. Using these reactions we demonstrate that aluminum can be selectively deposited on -CH(3)/-COOH-patterned SAMs. The possible reaction mechanisms involved in the Al film growth are discussed. These results indicate that photoactivated CVD (laser CVD) processes are suitable for the deposition of stable films of metals and other materials on organic films.

The synthesis of polycrystalline aluminum oxynitride (AlON) powders was investigated by the carbothermal reduction and nitridation (CRN) of amorphous precursor obtained by wet chemical processing. Co-precipitation processing was employed to achieve amorphous precursor from Al(NO3)3 solution dispersed by nanosized carbon particles, which was composed of Al(OH)3 and C particles homogeneously. The effects of the content of carbon black, pH value, and calcination temperature on formation of AlON phase were investigated by means of XRD, SEM and TEM, respectively. It was found that single phase AlON powder could be synthesized when the resultant precursors were calcined at 1750°C for 2 hours under flowing N2. Under optimal additional content of C (5.6wt%), the resultant AlON powders exhibited the primary particle size of about 1–3 μm with a specific surface area of 3.2 m2/g, which were superior to that of carbothermal reduction of immediate mixture of γ-Al2O3/C powders.

In a photoelectrochemical (PEC) cell for water splitting, the critical issue is charge separation and transport, which is usually completed by designing semiconductor heterojunctions. TiO2 anatase-rutile mixed junctions could largely improve photocatalytic properties, but impairs PEC water splitting performance. We designed and prepared two types of TiO2 heterostructures with the anatase thin film and rutile nanowire phases organized in different sequences. The two types of heterostructures were used as PEC photoanodes for water splitting and demonstrated completely opposite results. Rutile nanowires on anatase film demonstrated enhanced photocurrent density and onset potential, whereas strong negative performance was obtained from anatase film on rutile nanowire structures. The mechanism was investigated by photoresponse, light absorption and reflectance, and electrochemical impedance spectra. This work revealed the significant role of phase sequence in performance gain of anatase-rutile TiO2 heterostructured PEC photoanodes.

Dye-sensitized solar cell (DSSC) is a promising solution to global energy crisis and environmental problems owing to its easy fabrication, good durability and environmental friendliness. A DSSC consists of several components, the most prominent being an oxide semiconductor-based photoanode, a dye, an electrolyte and a counter electrode. Pt-loaded conducting glass has been widely exploited as the standard counter electrode for DSSCs. However, the high cost and the rarity of Pt limits the commercial applications of DSSCs. Therefore, developing high-efficient counter electrode materials to replace Pt has become research hotspot. Recently, carbon nanostructures have been demonstrated to be promising counter electrode materials for DSSCs due to its high electrochemical activity, low cost and high corrosion resistance. Transition metal sulfides have also found their application in DSSCs as counter electrodes. Particularly, ternary transition metal sulfide (CoNi2S4) has high electronic conductivity and redox ability due to the existence of cobalt and nickel ions. Therefore, it is expected that high conversion efficiency would be achieved by employing the carbon and CoNi2S4 nanostructured composites as counter electrodes.

We have investigated the selective electroless deposition (ELD) of Cu on functionalized self-assembled monolayers (SAMs). Previous studies have demonstrated that Cu deposits on -COOH and -CH(3) terminated SAMs using ELD. However, the deposited films were rough and contained irregular crystallites. Further, the copper penetrated through the film. In this Article, we demonstrate that copper can be selectively deposited on -COOH terminated SAMs with improved morphology and without penetration of copper through the organic layer. The method employs a Cu(II) seed layer and an additive, adenine or guanine. We demonstrate the efficacy of the technique on photopatterned -CH(3)/-COOH SAMs. Copper is observed to deposit only atop the -COOH terminated SAM area and not on the -CH(3) terminated SAM. The use of a Cu(II) seed layer increased the Cu ELD rate on both -COOH and -CH(3) terminated SAMs. The deposited copper layer strongly adheres to the -COOH terminated SAMs because the copper layer nucleates at Cu(2+)-carboxylate complexes. In contrast, the deposited copper layer can easily be removed from the -CH(3) terminated SAM surface because there is no specific copper-surface interaction. The additives adenine and guanine mediate the interaction of Cu(2+) and the deprotonated -COOH terminated SAMs via the formation of additive-carboxylate complexes. These complexes lead to significantly reduced copper penetration through the SAM. In the case of adenine, the diffusion of copper through the organic film was eliminated. This new technique for copper deposition will facilitate the development of inexpensive molecular electronics, sensors, and other nanotechological devices.

Target irradiation uniformity is very important in laser-produced plasmas experiments. The wavelength dependence of the irradiation uniformity is investigated in the joint scheme using a lens array (LA) and the technique of smoothing by spectral dispersion (SSD). It is proved that, for the long wavelength laser, lateral thermal conduction smoothing within the target is quite effective, while for the ultraviolet laser, SSD is the main smoothing mechanism. So SSD and other temporal smoothing methods are very necessary in producing uniform irradiation with laser beam of short wavelength.

Plasma-based flow control is one of the most promising techniques for aerodynamic problems, such as delaying the boundary layer transition. The boundary layer’s characteristics induced by AC-DBD plasma actuators and applied by the actuators to delay the boundary layer transition on airfoil at Ma = 0.3 were experimentally investigated. The PIV measurement was used to study the boundary layer’s characteristics induced by the plasma actuators. The measurement plane, which was parallel to the surface of the actuators and 1 mm above the surface, was involved in the test, including the perpendicular plane. The instantaneous results showed that the induced flow field consisted of many small size unsteady vortices which were eliminated by the time average. The subsequent oil-film interferometry skin friction measurement was conducted on a NASA SC(2)-0712 airfoil at Ma = 0.3. The coefficient of skin friction demonstrates that the plasma actuators successfully delay the boundary layer transition and the efficiency is better at higher driven voltage.

The experimental results show that there are two growth modes of crystalline metal oxide in the colloidal crystal template, which depend on the quality of the colloidal crystal. In well-ordered col...

The counter electrode has a great influence on the performance of the dye-sensitized solar cells (DSSCs). The research and development of Pt-free counter electrode is becoming one of the hot areas in the field of DSSCs. Herein, we successfully synthesized a ternary metal sulfide (CoNi2S4) nanostructure on FTO substrate by hydrothermal method and investigated its application as counter electrode. The as-synthesized sample could exhibit better electrocatalystic property than that of Pt, and corresponding DSSCs have comparable conversion efficiency with typical Pt catalyzed cells. The easy synthesis, low cost and excellent electrocatalytic property may help the CoNi2S4 nanostructure stand out as an alternative counter electrode in DSSCs.

We have developed a method by which to selectively and reproducibly deposit ZnO films on functionalized self-assembled monolayers (SAMs) using chemical bath deposition (CBD). The deposition bath is composed of zinc acetate and ethylenediamine. The deposition reaction pathways are shown to be similar to those observed for sulfides and selenides, even though ethylenediamine acts as both an oxygen source and a complexing agent. On -COOH terminated SAMs, Zn-carboxylate surface complexes act as nucleation sites for ion-by-ion growth, leading to the formation of adherent ZnO nanocrystallites. Cluster-by-cluster growth is also observed, which produces weakly adherent micrometer-sized ZnO crystallites. On -CH3 and -OH terminated SAMs, only micrometer-sized ZnO crystallites are observed because Zn(2+) does not complex with the SAM terminal group, preventing nucleation of the nanocrystalline phase. The application of either ultrasound ("sonication-assisted CBD") or stirring promotes ion-by-ion ZnO growth on -COOH terminated SAMs. Stirring produces smoother but less reproducible ZnO films than sonication-assisted CBD.

The effects of the arrangement position and control parameters of nanosecond dielectric barrier discharge (NS-DBD) plasma actuators on lift enhancement for flying wing aircraft were investigated through wind tunnel experiments at a flow speed of 25 m s−1. The aerodynamic forces and moments were obtained by a six-component balance at angles of attack ranging from −4° to 28°. The lift, drag and pitching moment coefficients were compared for the cases with and without plasma control. The results revealed that the maximum control effect was achieved by placing the actuator at the leading edge of the inner and middle wing, for which the maximum lift coefficient increased by 37.8% and the stall angle of attack was postponed by 8° compared with the plasma-off case. The effects of modulation frequency and discharge voltage were also investigated. The results revealed that the lift enhancement effect of the NS-DBD plasma actuators was strongly influenced by the modulation frequency. Significant control effects were obtained at f = 70 Hz, corresponding to F + ≈ 1. The result for the pitching moment coefficient demonstrated that the plasma actuator can induce the reattachment of the separation flows when it is actuated. However, the results indicated that the discharge voltage had a negligible influence on the lift enhancement effect.

We report the successful growth of NiCo2S4 nanosheet films converted from NiCo2O4 nanosheet films on fluorine-doped tin oxide substrates by a low-temperature solution process. Low-cost NiCo2S4 and NiCo2O4 nanosheet films were directly used for replacing conventional Pt and NiO as counter electrodes and photocathodes, respectively, to construct all-nano p-type dye-sensitized solar cells (p-DSSCs) with high performance. Compared to Pt, NiCo2S4 showed higher catalytic activity towards the I-/I3 - redox in electrolyte, resulting in an improved photocurrent density up to 2.989 mA/cm2, which is the highest value in reported p-DSSCs. Present p-DSSCs demonstrated a cell efficiency of 0.248 % that is also comparable with typical NiO-based p-DSSCs.

ZnO nanostructures were manipulated, via a low-temperature solution process, from pure nanorod arrays to complex nanostructures of microflowers on nanorod arrays with adjusted quantities of flowers. We proposed the mechanism of local dissolution-driven growth to rationally discuss the novel growth process. These nanostructures were used as photoanodes in dye-sensitized solar cells. Compared to pure nanorod arrays, the nanorod array-microflower hierarchical structures improved the power conversion efficiency from 0.41% to 0.92%, corresponding to a 124% efficiency increase. The enhancement of the efficiency was mainly ascribed to the synergistic effect of the enhanced surface area for higher dye loading and the improved light harvesting from efficient light scattering. Present results provide a promising route to improve the capability of light-harvesting for ZnO nanorod array-based DSSCs.

Vortex control is a thriving research area, particularly in relation to flying wing or delta wing aircraft. This paper presents the topological structures of vortex flow on a flying wing aircraft controlled by a nanosecond plasma dielectric barrier discharge actuator. Experiments, including oil flow visualization and two-dimensional particle image velocimetry (PIV), were conducted in a wind tunnel with a Reynolds number of 0.5 × 106. Both oil and PIV results show that the vortex can be controlled. Oil topological structures on the aircraft surface coincide with spatial PIV flow structures. Both indicate vortex convergence and enhancement when the plasma discharge is switched on, leading to a reduced region of separated flow.

This study examines the potential hazard of an individual nanomaterial on the Cu biotoxicity to aquatic organisms.Daphnia magnain the absence or presence of nano-TiO2was exposed to Cu. Maintaining nano-TiO2at a safe concentration cannot eliminate its potential hazard. The biomarkers superoxide dismutase, catalase, and Na+/K+-ATPase inD. magnawere measured. Cu in the presence of nano-TiO2induced higher levels of oxidative stress and physiological damage because of the sorption of Cu. Nano-TiO2also caused Na+/K+-ATPase inhibition possibly by impeding the Na+/K+transfer channel. The correlations among the biomarkers, mortality, and accumulation further showed that the overloading reactive oxygen species generation caused by nano-TiO2contributed to deeper oxidative stress and physiological regulation, thereby causing greater toxic injury.

Electroless nanowire deposition on micropatterned substrates (ENDOM) is a promising new technique by which to direct the synthesis and precise placement of metallic nanowires. ENDOM is generally applicable to the preparation of metallic, semiconducting, and even insulating nanowires on technologically relevant substrates, is inexpensive, and can achieve high growth rates. The deposited nanowires are ultralong (centimeters) and can be patterned in arbitrary shapes. We demonstrate ENDOM using the growth of nickel nanowires. By controlling the deposition time, the width of the nanowires can be varied from 200 to 1000 nm and the height can be varied from 7 to 20 nm.

A novel compact broadband multilayer microstrip antenna with half u-slot is presented in this paper. This patch antenna has two layers, the top layer and the middle layer. Both layers of the patch antenna were connected to the ground plane with shorting wall. In this paper, we proposed a multilayer with half u-slot technique to achieve a wide impedance broadband patch antenna with small geometric size. The VSWR, gain and radiation pattern of this antenna are simulated. The measured VSWR of it is also shown in the paper. The results are discussed in detail

A novel compact broadband multilayer microstrip antenna with half e-slot is presented in this paper. This patch antenna has two layers, the top layer and the middle layer. Both layers of the patch antenna were connected to the ground plane with shorting wall. In this paper, we proposed a multilayer with half e-slot technique to achieve a wide impedance broadband patch antenna with small geometric size. The VSWR, gain and radiation pattern of this antenna are simulated. The measured VSWR of it is also shown in the paper. The results are discussed in detail.

A novel compact broadband multilayer microstrip antenna is presented in this paper. The VSWR, gain and radiation pattern of this antenna are simulated. The measured VSWR of it is also shown in the paper. The results are discussed in detail.

Optical tomography technique is very important in changing conventional techniques for the development of imaging science. It will be applied widely in the fields of biomedical imaging, material structure analyzing and blurry martial target distinguishing etc. In this paper, we introduce the application of a multimode optical fiber sensor in tomography technology. Optic fiber with polished terminations requires the incident ray within a certain angle, so it usually causes deficiency of the light power entered into the optical fiber and diffuse the emergent ray, so polished terminations make it difficult to receive and detect the emergent rays. In order to solve the two problems above, a sphere lens is designed for one termination and a cylinder lens is designed for the other termination. This paper uses mathematics to analyze the relationship between the sphere lens radius, the cylinder lens radius, refractive index of the optical fiber. The relationship between the scanning angles and the numbers of the numbers of the received optical fiber is researched in the air medium, and the designing method for the sphere lens and the cylinder lens are present.

We discuss the propagation characteristics of the electromagnetic field in the symmetric metal-clad planar uniaxial crystal waveguide. For the special waveguide structure that the optical axis of the crystal is on the x-z plane, where x is the normal direction of the waveguide plane and z is the propagation direction, we obtain the analytic accurate solution of the modal fields. It is shown that:(1) there are TE mode and TM mode in this special waveguide structure; 2) The direction of the wave vector and the Poynting vector of TM mode are not collinear; (3) The principal mode of the waveguide is the principal mode of TE mode for the negative uniaxial crystal, but the one of TM mode for the positive uniaxial crystal.