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In this work, the preparation of Fe3O4/graphene oxide (GO) nanocomposite and its application in radio frequency (RF) on-chip transformer was investigated. The Fe3O4/GO nanocomposite was synthesized by using solvothermal method in the presence of GO and integrated into an on-chip transformer by using a novel post-CMOS process. The experimental results show that the Fe3O4 nanoparticles (with $\sim 13$ nm in diameter) are uniformly attached onto the surface of GO and the nanocomposite exhibits typical ferromagnetic behavior. Compared with the identical structural air-core transformer, the inductance ( $L$ ), quality factor ( $Q$ ), and coupling coefficient ( $K$ ) of the device with Fe3O4/GO nanocomposite film are increased by 28%, 24%, and 11% at 1 GHz, respectively. The enhancement effect of the magnetic film on the RF performance of the transformer has been maintained until 2 GHz. It is believed that Fe3O4/GO nanocomposite has great potential application in RF on-chip transformers with operation frequency below 2 GHz.

FeNi-layered double hydroxide (LDH) is thought to be an excellent electrocatalyst for oxygen evolution reaction (OER) but it always shows extremely poor electrocatalytic activity toward hydrogen evolution reaction (HER) in alkaline media. Hence, it is significant to improve its HER activity to make it a bifunctional electrocatalyst for the decomposition of water. Here, a simple galvanostatic electrodeposition method was designed for the successful construction of the bifunctional FeNi3@FeNi LDH electrocatalyst. The as-prepared catalyst displayed excellent electrocatalytic activity for HER/OER in 1.0 M KOH. To drive the current density of 10 mA cm−2 for HER/OER, an overpotential of 106/199 mV was needed, respectively. In a two-electrode system with the FeNi3@FeNi LDH/NF as the anode and the cathode simultaneously, the overpotential hardly changed after continuously working for 168 h at 10 mA cm−2. Compared with other FeNi-based catalysts, the present catalyst possessed close or better electrocatalytic activity.

A two-step sequential deposition has been a reliable method to synthesize large-area and high-quality perovskite films due to its better reproducibility. However, the long-term performance and stability of thin films are adversely affected by the slow and incomplete transformation of PbI2 to perovskites. Here, we propose a nanosecond laser shock annealing process to induce ultrafast organic salt diffusion into the PbI2 layer to modulate the crystalline structure, residual tensile strain, and electron transport kinetics in two-step fabricated halide perovskite films. We found that pulse-laser induced ultrafast diffusion reduces the thickness of the residual PbI2 layer at the bottom of the perovskite film fabricated by a two-step method, resulting in the reduction of residual tensile strain by over seven times. The shocking moment of the nanosecond laser promotes the diffusion of the organic salt to the PbI2 layer. Compared to traditional thermal annealing, ultrafast laser shock annealing enhances the molecular interaction, which significantly affects the orbital overlap resulting in band structure changes. Laser shock annealing induced modulation of band structures in perovskites leads to remarkable improvement in their carrier lifetime, producing a responsivity (R) and detectivity (D*) of 2.45 A W−1 and 1.48 × 1012 Jones, respectively. Besides, the stability testing under various harsh thermal and humid thermal conditions shows that laser shock annealing improves the stability of perovskite thin films as a result of the reduced PbI2 layer and residual tensile strain. The presented technology that utilizes laser shock annealing to modulate the ultrafast diffusion in the PbI2 layer provides a guideline for future improvement in the device performance and stability of hybrid organic–inorganic halide perovskites.

In this work, a CoNxC active sites-rich three-dimensional porous carbon nanofibers network derived from bacterial cellulose and bimetal-ZIFs is prepared via a nucleation growth strategy and a pyrolysis process. The material displays excellent electrocatalytic activity for the oxygen reduction reaction, reaching a high limiting diffusion current density of −7.8 mA cm−2, outperforming metal–organic frameworks derived multifunctional electrocatalysts, and oxygen evolution reaction and hydrogen evolution reaction with low overpotentials of 380 and 107 mV, respectively. When the electrochemical properties are further evaluated, the electrocatalyst as an air cathode for Zn-air batteries exhibits a high cycling stability for 63 h as well as a maximum power density of 308 mW cm−2, which is better than those for most Zn-air batteries reported to date. In addition, a power density of 152 mW cm−2 is provided by the solid-state Zn-air batteries, and the cycling stability is outstanding for 24 h. The remarkable electrocatalytic properties are attributed to the synergistic effect of the 3D porous carbon nanofibers network and abundant inserted CoNxC active sites, which enable the fast transmission of ions and mass and simultaneously provide a large contact area for the electrode/electrolyte.

A miniaturized, high electronic efficiency, S-band metamaterial extended interaction klystron (MEIK) is proposed. The metamaterial-based extended interaction resonant cavities were designed, fabricated, and tested, the assembled and cold-tested results confirm the feasibility of miniaturization in MEIK. Furthermore, the particle-in-cell (PIC) simulation predicts that, typically, when the beam voltage and current are 30 kV and 3 A, respectively, the focusing magnetic field is 1000 G, a 3-cavity MEIK yields the output power of 56 kW at 2.453 GHz, with the saturated gain of 47 dB and the electronic efficiency of 62%, and, importantly, with the cavity diameter of its interaction structure being ~1/2 of a conventional extended interaction klystron. As a power amplifier, the emerging MEIK with its miniaturization and high electronic efficiency has potential applications such as in future accelerators and microwave heating systems.

The microstrip meander-line traveling wave tube (TWT) is a kind of small sized, low voltage, low cost, and easy to fabricate TWT. It is an attractive choice for many applications, such as communication systems, phased array radars, security detectors, and electronic counter measure (ECM) instruments. In this paper, a Ka band U-shape meander-line slow wave structure (SWS) supported by a diamond rod is presented. The dispersion characteristics of this meander-line SWS are analyzed using CST MW Studio. The S-parameter simulation results show that the reflection is below − 15 dB between 32 and 38 GHz, and the particle-in-cell (PIC) simulation reveals that this meander-line TWT can produce 57 W output power at 36 GHz, when it is driven by a 8.1 kV, 0.04 A sheet beam with rectangular cross-sectional area of 1.0 mm × 0.12 mm. This meander-line SWS is manufactured, assembled, and tested. The good agreement between the simulated and measured S11 has been achieved and the mismatch between the simulated and measured S21 has been discussed at the end.

The T-joint structure is a typical stiffened skin - fuselage frame joint and an important component in the integral design of composite material. Delamination of the interface between skin and frame is a typical failure mode of T-joint. Z-pin can significantly improve the interface performance between skin and frame. In this paper, the damage process and failure mode of z-pinned joint of the T-joints are studied through simulation and experiment. First, pull-out strength experiments are performed to determine the failure modes of z-pinned joint of the T-joints. The influence of clamping span on the pull-out load is also studied in the T-joint experiments. Our results show that z-pin can significantly improve the ultimate pull-out load and connection efficiency of composite T-joint. The improvement effect became more obvious with the decrease of clamping span. Second, the bilinear cohesive behavior and nonlinear spring elements are introduced to simulate T-joints the delamination of interface and the effects of z-pin under the pull-out load. Simulation results are in good agreement with the experiments, which verifies the reliability of the interface damage simulation of cohesive behavior contact and the z-pin simulation of nonlinear spring element. Our simulations and experiments reveal similar damage failure modes together.

MnCo2O4+x nanowire arrays have been successfully grown on carbon sponge (CS) via a simple hydrothermal route with sequential thermal treatment, employing CoSO4·7H2O, MnSO4·H2O and urea as the initial reactants. The as-prepared product, labeled MnCo2O4+x/CS, was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), (high resolution) transmission electron microscopy (TEM/HRTEM), nitrogen adsorption–desorption isotherms, Raman spectrometry and X-ray photoelectron spectroscopy (XPS). The experiments showed that the presence of CS could affect the phase and morphology of the final manganese cobaltite. Without the presence of CS, a MnCo2O4.5 phase with spherical microstructures was produced; and with the presence of CS, a mixed phase of MnCo2O4.5 and MnCo2O4 with wire-like nanostructures was obtained. It was found that the final MnCo2O4+x/CS markedly improved the electrochemical and catalytic properties against MnCo2O4.5. At a current density of 1.0 A g−1, the as-prepared product exhibited a specific capacitance of 405 F g−1, which was far higher than 158.8 F g−1 of pure MnCo2O4.5. Under the same experimental conditions, simultaneously, the MnCo2O4+x/CS catalyst only took ∼6 min for catalyzing 92% of 4-nitrophenol (4-NP) to 4-nitroaniline (4-AP), which was shorter than ∼10 min of the pure MnCo2O4.5 catalyst.

Li4Ti5O12/Ag composite nanobelts with an average width of ca. 1.12 μm were successfully synthesized via a facile electrospinning, and the average width is ca. 1.12 μm. The Li4Ti5O12/Ag composites show perfect initial discharge capacity (178.72 mA h g–1 at 0.1 C), better rate capability (131.70 mA h g–1 after cycled at 15 C) and super cycling stability (172.21 mA h g–1 after 100 cycles at 0.2 C) compared to pure Li4Ti5O12 nanobelts when used as anode materials for lithium ion batteries. The excellent electrochemical performance is explained by the nanostructure of obtained samples which could provide an effective ion and electron transport in the longitudinal direction. The addition of Ag could enhance charge transfer due to increased electronic conductivity. Our new findings provide an effective way to improve the electrochemical performance of Li4Ti5O12 anode materials for lithium ion batteries.

Herein, flexible piezoresistive sensors with 3D surface-filled (SF) carbon black (CB)/graphene (GR) conductive composite layers were fabricated through 3D printing and modified dip-coating process, which show high stretchability of 15.5 times, good sensitivity of200. 73 kPa−1, high gauge factor of 17.20 and excellent stability (>2000 cycles). In addition, the novel sensor demonstrated the applications in detecting tiny and big human activities, exhibiting its great potential for application in wearable electronics.

Herein, the application of Fe 3 O 4 nanoparticles in radio-frequency (RF) integrated transformer was investigated. The Fe 3 O 4 nanoparticles were integrated into an integrated transformer by using a novel post-CMOS process. Compared with the identical structural air-core transformer, the inductance $(L)$ , quality factor $(Q)$ and coupling coefficient $(K)$ of the device with Fe 3 O 4 nanoparticles film are increased by 30%, 5% and 10% at 1GHz respectively. It demonstrated that Fe 3 O 4 nanoparticles are suitable for RF integrated transformers.

NiZnAl layered double hydroxides (LDH) with Ni/Zn/Al ratios ranging from 0.1/2/1 to 1/2/1 were papered by coprecipitation. The prepared samples were characterized by multiple techniques including X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse-reflectance spectroscopy (UV-vis DRS). The incorporation of Ni2+ into the brucite sheets preserves the layered structure of ZnAl LDH. The doped Ni2+ serves as the photogenerated charges separator and improves the visible light photocatalytic activity of ZnAl LDH at a reasonable content. A degradation mechanism based on the hydroxyl radical as the active species was proposed.

Dendritic PbTe microstructures were successfully obtained by a simple potentiostatic electrodeposition route from an electrolyte consisting of Pb(NO3)2, Na2TeO3 and HNO3 at room temperature. Different from Xiao's report (Electrochimica Acta, 2006, 52, 1101), in which the effects of the deposition potential and original concentrations of Pb and Te sources on the film composition and microstructure of PbTe obtained from an acidic nitrate bath were investigated, our research mainly focused on the discussion of the role of HNO3 in the formation of PbTe dendrites. Experiments uncovered that some experimental parameters, including the deposition potential, the time and the additive, only slightly affected the formation of PbTe dendrites in the presence of HNO3 at a certain concentration. Also, no PbTe dendrites were obtained under the same deposition conditions after HNO3 had been replaced by other strong acids such as HCl, H2SO4 and HClO4, implying that HNO3 played a crucial role in the formation of dendritic PbTe microstructures. Obviously, the present work is of great significance in directing the fast electrodeposition of dendritic PbTe microstructures in practical applications.

The three-dimensional (3D) flexible piezoresistive sensors have promising potentials in wearable electronics because of their abundant structure forms and sensing functions. It is desired to develop 3D flexible piezoresistive sensors with high sensitivity and good stability. Herein, highly sensitive, stable and 3D flexible piezoresistive sensor with novel surface-filled (SF) graphene nanosheets (GNs) conductive layer was fabricated by fused deposition molding (FDM) 3D printing. Due to the surface-filled GNs conductive layer, the flexible piezoresistive sensor shows high stretchability of 1960% strain, good sensitivity of 175.57 kPa−1 at an applied pressure 2000 cycles), the short mechanical response time (105 ms) and recovery time (66 ms). Compared with the SF-CNTs@styrene-ethylene-butylene-styrene (SEBS) sensor, the sensitivity of the SF-GNs@SEBS sensor is increased by 15.6%, and the GF values are increased by 167% (0–50%) and 974% (50–100%) respectively, indicating that GNs is more suitable for the sensor with the SF structure than CNTs. After 2000 compression/release cycles, the response signal of the GNs surface-filled sensor is basically not degraded, while the response signal of the GNs surface-coated sensor is degraded by 50%, indicating that the GNs surface-filled sensor has a far better stability than the GNs surface-coated sensor. Besides, the piezoresistive sensor was demonstrated the applications in detecting human activities, such as speaking, finger tapping, cheek bulging, and neck bending, exhibiting its great potential for application in health monitoring.

Li4Ti5O12/Li2TiO3 composite nanofibers with the mean diameter of ca. 60 nm have been synthesized via facile electrospinning. When the molar ratio of Li to Ti is 4.8:5, the Li4Ti5O12/Li2TiO3 composite nanofibers exhibit initial discharge capacity of 216.07 mAh g−1 at 0.1 C, rate capability of 151 mAh g−1 after being cycled at 20 C, and cycling stability of 122.93 mAh g−1 after 1000 cycles at 20 C. Compared with pure Li4Ti5O12 nanofibers and Li2TiO3 nanofibers, Li4Ti5O12/Li2TiO3 composite nanofibers show better performance when used as anode materials for lithium ion batteries. The enhanced electrochemical performances are explained by the incorporation of appropriate Li2TiO3 which could strengthen the structure stability of the hosted materials and has fast Li+-conductor characteristics, and the nanostructure of nanofibers which could offer high specific area between the active materials and electrolyte and shorten diffusion paths for ionic transport and electronic conduction. Our new findings provide an effective synthetic way to produce high-performance Li4Ti5O12 anodes for lithium rechargeable batteries.

Mg-Al layered double hydroxides (LDHs) adsorbent was synthesized in situ on γ-Al2O3 for the removal of Cr(VI) from aqueous solution. The material was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electronic microscopy and thermogravimetry and differential thermal analysis. Compared to the LDHs powder, the calcined LDHs sorbent prepared in situ on γ-Al2O3 had higher specific surface area and was easy to recover and reuse. The adsorptive capacity for removing Cr(VI) from aqueous solution was resulting from the memory effect of LDHs based on the XRD results. Both the pseudo-second-order kinetic model and the Langmuir model fit the experimental data well. Furthermore, the adsorbent exhibits excellent sorption–regeneration performances.

Crystalline scorodite (FeAsO4·2H2O) is a common arsenic-(As-)containing solid waste produced from nonferrous metallurgical processes. Its stability is the key factor to determine environmen...

While lithium-ion batteries (LIBs) have been widely used in commercial devices, finding suitable anode materials for alkali metal batteries is still challenging. Therefore, Ni3S2/Ni@N-doped carbon composite electrode was fabricated as the anode for alkali metal batteries. It was found that the Ni3S2/Ni@N-doped carbon electrode achieved a capacity of 742 mAh g−1 at the 1500th cycle at the current density of 1000 mA g−1 for LIBs, and obtained 275 mAh g−1 at the 250th cycle during 500 mA g−1 for Na+ storage. Moreover, it showed 52 mAh g−1 after 50 cycles at 100 mA g−1 for K+ storage. The excellent performances of this electrode is likely due to the combined effect of Ni and C layer. This work provides a simple approach approach for the design of high-performance materials that can be applied to commercial production as a potential substitute for the current alkali ion battery anodes.

A mutual template route was designed to prepare Ni-P/Fe(OH)3-Cu nanotube arrays with a high electrocatalytic activity for OER. In 1.0 M KOH solution, the as-obtained hybrid electrocatalyst required only a low overpotential of 271 mV to achieve a current density of 20 mA cm−2 with a small Tafel slope of 57.7 mV dec−1. After 1000 CV cycles at the scan rate of 100 mV s−1, the overpotential of the catalyst hardly increased; and after continuously catalyzing for 130 h at 20 mA cm−2, the potential only slightly increased, implying that the as-obtained hybrid electrocatalyst possessed excellent cycle stability and long-term stability. The above outstanding electrocatalytic activity should be ascribed to its special tubular structure and the synergicaction between Ni-P alloy and Fe(OH)3 nanotubes. Moreover, the presence of elemental copper, which was formed by the in-situ electrochemical reduction of Cu(OH)2, also enhanced the catalytic performance due to its excellent electrical conductivity.

We demonstrate a tunable optical parametric oscillator in a periodically poled congruently grown lithium tantalite whispering gallery mode resonator. The resonator is mechanically polished to millimeter size, and the quality factor is approximately 107 at 1064 nm. Our experiments show that this kind of resonator is capable of reaching a very low threshold and having a wide tuning range. Combined with its narrow resonant linewidth, it is potentially used as a compact, widely tunable, and narrow-linewidth infrared to mid-infrared laser source.

A facile two-step route is designed to synthesize chain-like Fe3O4@resorcinol-formaldehyde resins–Ag composite microstructures (denoted as Fe3O4@RF–Ag). Chain-like Fe3O4@RF microstructures are firstly obtained by the in situ polymerization of RF on Fe3O4 microspheres under the assistance of an external magnetic field; and then, Ag nanoparticles are strewn on the surface of the RF via in situ reduction by hydrazine hydrate. The as-obtained chain-like Fe3O4@RF–Ag microstructures are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), (high-resolution) transmission electron microscopy (HRTEM/TEM) and energy dispersive spectrometry (EDS). Experiments indicate that the as-prepared chain-like Fe3O4@RF–Ag microstructures can not only serve as outstanding antibacterial agents against bacteria including Staphylococcus aureus and Escherichia coli, but also as highly efficient catalysts for the hydrogenation of various compounds, including 4-nitrophenol, methylene blue and Rhodamine B. Also, the as-prepared chain-like Fe3O4@RF–Ag microstructures can be conveniently regenerated under extra magnetic field due to the presence of Fe3O4 and they show good cyclic stability, which is important for practical applications.

An experimental study of an intense current electron beam diode with a foil-free annular graphite cathode is carried out. The explosive emission images of a graphite cathode at discharging voltages of 240 kV and 780 kV and the attenuation images of cathode carbon ions at different magnetic fields are recorded using a 24-framing camera for the first time. The experimental results show that when the discharging voltage is 240 kV, the light spots of the plasma generated by the explosive emission process are randomly distributed over the annular cathode and the size and brightness of the light spots of the plasma are also randomly distributed; when the discharging voltage is 780 kV, if the background light generated by Čerenkov radiation is not taken into account, the light spots of the plasma generated by the explosion emission is more uniform than that when the discharging voltage is 280 kV and the brightness of the light spots of the plasma is higher, too. Meanwhile, when the axial magnetic field strength is less than 0.77 T, the plasma spots appear in the gap between the cathode and the anode. The smaller the axial magnetic field strength is, the higher the brightness of the plasma spots will be. In addition, when the discharging voltage is 780 kV/200 ns and the axial magnetic field strength is 0.77 T, a rough calculation indicates that the axial diffusion velocity of the cathode carbon ions ranges from 1.77 cm/μs to 2.1 cm/μs.

Grass-like Ni/Cu nanosheet arrays were successfully grown on copper foam by a simple galvanostatic electrodeposition route. Experiments showed that the as-deposited grass-like Ni/Cu nanosheet arrays possessed excellent electrocatalytic activity for hydrogen evolution reaction (HER). In 1 M KOH solution, the nanosheet arrays only required a low overpotential of 38 mV to deliver a current density of -10 mA cm-2. Simultaneously, the present catalyst also presented a high durability. After continuously catalyzing for 50 h at a current density of -30 mA cm-2, the overpotential had no obvious increase. The above outstanding electrocatalytic activity should be attributed to the special grass-like structure of the catalyst, which exposed more effective active sites, promoted electrolyte penetration and facilitated gas diffusion. Compared with other catalysts with complex compositions, the present Ni/Cu binary catalyst is easily synthesized, cost-efficient and highly active for HER, which provides a new selection for electrochemical water splitting in practical applications.

The Cu-doped ZnAl layered double hydroxides (LDH) were papered by coprecipitation. The prepared samples were characterized by mutiple techniques including X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse-reflectance spectroscopy (UV-vis DRS). The doping of Cu2+ into the LDH sheets results in formation of the distorted CuO6 octahedrons which contribute for the excitation of electrons under visible light. The doped Cu2+ also serves as photo-generated charges separator and improves the visible-light-driven photocatalytic activity of ZnAl LDH. A degradation mechanism based on the hydroxyl radical as the active species was proposed.

In this paper, we propose a MW-level sheet electron beam microwave oscillator operating in X band. The slow wave structure (SWS) of the oscillator consists of the waveguide and the complementary split ring resonators (CSRRs) array. The high frequency characteristics includes dispersion and interaction impedance are analyzed by using the CST eigenmode solver. The simulation results show that the cold bandwidth ranges from 9.53 GHz to 9.78 GHz, and the interaction impedance is higher than 600 Ohm. We then design a waveguide coupler for the SWS, the simulated transmission coefficient is greater than -5 dB from 9.53 GHz to 9.65 GHz. Finally, we study the MW-level microwave oscillator by using CST simulation, the output power is up to 1.22 MW and the electronic efficiency is 16.3% at 9.551 GHz when the electron beam voltage and current are 170 kV and 22 A, respectively.

A nanostructured Ag loaded Bi3NbO7 photocatalyst was synthesized by the co-precipitation combined with photodeposition method, and characterized by XRD, XPS, SEM, BET nitrogen adsorption–desorption, and UV–vis DRS. Photocatalytic activities of the Ag/Bi3NbO7 samples were evaluated by the degradation of methyl orange under visible light irradiation. It was shown that the best photocatalytic activity was obtained on sample with Ag loading level of 2 wt%. It was suggested that the increase in photocatalytic activity of Ag/Bi3NbO7 photocatalyst was explained on the basis of the electron trapping ability, the electron exciting ability and the surface plasmon resonance effect of metallic Ag particles.

We demonstrate an efficiency-enhanced picosecond (ps) mid-infrared radiation via optical parametric downconversion. Based on a cascaded periodically poled MgO-doped stoichiometric lithium tantalate crystal (MgO:sPPLT), a tandem optical parametric oscillation-optical parametric amplification (OPO-OPA) process is achieved. Compared with a single OPO process, the conversion efficiency obtains an enhancement of 71%.

In this paper, we present an S band metamaterial-based sheet beam device. The performance of this device is studied by particle-in-cell simulations and hot experiments. The simulated results indicate a ∼2.85 GHz microwave signal with ∼1.8 MW peak output power is generated at the output port near the cathode. Meanwhile, the measured results show that the signal has ∼650 kW peak output power at ∼2.87 GHz. The facts show that this metamaterial-based sheet beam device can be developed to a novel high-power microwave source.

Zn/Al-layered double hydroxides (LDHs) containing the organic anion of 2,4-dihydroxybenzophenone-5-sulfonate (DHBS) have been synthesized by co-precipitation method. Surface, structural, thermal and absorption properties of the ZnAl-DHBS-LDHs nanohybrids were characterized by BET analysis, scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis and UV–visible spectroscopy. The results revealed that organic UV absorbent-DHBS has been intercalated into the interlayer spaces of ZnAl-LDHs and the intercalation of DHBS in LDHs interlayer galleries resulted to higher thermal stability and better UV absorption ability; these show that the hybrid ZnAl-DHBS-LDHs phase has potential applications as a UV absorber.

New organic-inorganic composite of 2,4-dihydroxybenz ophenone (BP-1) encapsulation into dodecylbenzene-sulfonate (DBS) modified layered double hydroxide (LDH) was successfully prepared. The surface, structural,thermal and absorption properties of the BP-1/DBS-LDH nanohybrid was characterized by BET analysis,scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG) and diffuse reflectance UV-Vis absorbance spectra (DRUV-vis). Theinterlayer configuration of composite and the adsorption mechanism of BP-1 on MgAl-DBS-LDH werediscussed. It was suspected that DBS anions located in the form of monolayer arrangement with a 75° antiparallel angle between dodecylbenzen esulfonate chain axis. The diffuse reflectance UV-Vis absorbance resultsrevealed that the UV absorbing wavelength of BP-1/DBS-LDH evidently extends to about 400 nm, whichshows that the BP-1/DBS-LDH has the potential application as a UV absorber.

The synthesis of ZnFe-CO3 and ZnFe-SO4 Hydrotalcites (HTLCs) has been previously described in numerous literature reports but these methods contain impurity phases that arise from a lack of understanding of the experimental conditions under which these impurities form during the precipitation of these types of HTLCs. Furthermore, the majority of these reports in which impurities are present in addition to the ZnFe-CO3 and ZnFe-SO4 HTLCs have then been used for environmental and catalytic applications leading to the misinterpretation of their materials properties as a result of the fact that they contain non-HTLC phases. In our study, we have developed a new and improved co-precipitation method for the synthesis of ZnFe-CO3 and ZnFe-SO4 HTLCs free from impurities that are experimentally and rationally based on the use of a proper: (1) Iron source (Fe2+), (2) oxidant (30% H2O2) and (3) target pH (pH of 7) to avoid the commonly found impurities in the literature. The synthesized ZnFe-CO3 and ZnFe-SO4 HTLCs are then characterized via the use of ICP-OES, XRD, ATR-IR, Raman, SEM, TEM, BET and TGA to explore their chemical and physical properties. Our work here offers the research community a new and improved synthesis method for the preparation of ZnFe-CO3 and ZnFe-SO4 HTLCs free from impurities designed for applications in a variety of multidisciplinary research areas.

The transport of a rectangular sheet beam in a metamaterial-loaded waveguide has been theoretically studied. It is found from the theoretical analysis that the space-charge field can lead to the beam curling under the uniform axial magnetic focusing. The simulation results also verify the theoretical analysis. This work lays a foundation for developing new vacuum electron devices based on metamaterials.

This work presents a simple and direct method for synthesizing Mg/Al-layered double hydroxides (MgAl-LDHs) film on an Mg sheet by in situ hydrothermal crystallization with urea hydrolysis, and protecting the Mg sheet from corrosion. The morphology and structure of the LDHs film were characterized by scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy, respectively. A uniform and compact thin film was formed, of which the LDHs platelets were highly oriented with their ab-face perpendicular to the Mg substrate. XRD pattern and FT-IR spectrum show that MgAl-LDHs film was formed accompanied with Mg(OH)2. Polarization measurements showed that the LDHs film exhibited a low corrosion current density value of 10−6 A/cm2. The strong adhesion between the film and the substrate was observed by cross-cutting method. These results indicated that the LDHs film can effectively protect Mg sheet from corrosion.

Simultaneous incorporation of palladium and zirconium ions in Mg–Al layered double hydroxides (LDHs) was attempted by co-precipitation. Mixed oxides were obtained by calcination at 500 °C. XRD patterns of as-synthesized samples showed the formation of well-crystallized LDHs at lower Zr contents. The CO 3 2− content of the solids has been determined to have information on the possible incorporation of Zr 4+ into the brucite layer of the hydrotalcites. The values obtained showed that Zr 4+ can incorporate into brucite sheets at Zr content lower than 10 mol%. SEM and TEM images indicated that the resulted LDHs with lower Zr content exhibited plate-like structure. Thermal calcination at 500 °C results in the formation of mixed oxides containing MgO, PdO, ZrO 2 crystallites and a solid solution formed by some of the Zr 4+ cations dissolving along with Al 3+ to MgO lattice.

Co-doped ZnAl layered double hydroxides (LDH) were papered by coprecipitation. The prepared samples were characterized by multiple techniques including X-ray Diffraction (XRD), Brunauer−Emmett−Teller (BET) surface area, Scanning Electronic Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS) and UV−Vis Diffuse-Reflectance Spectroscopy (UV−Vis DRS). The incorporation of Co 2+ into the ZnAl LDH sheets as CrO 6 octahedron forms a new energy level which contributes for the excitation of electrons under visible light. The doped Co 2+ at a reasonable content also serves as photo-generated charges separator and improves the visible light photocatalytic activity of ZnAl LDH. A degradation mechanism based on the hydroxyl radical as the active species was proposed. Copyright © 2018 BCREC Group. All rights reserved Received: 3rd February 2018; Revised: 8th July 2018; Accepted: 13rd July 2018 How to Cite : Li, D., Fan, L., Qi, M., Shen, Y., Liu, D., Li, S. (2018). Enhanced Visible-Light-Driven Photocatalytic Activity of ZnAl Layered Double Hydroxide by Incorporation of Co 2+ . Bulletin of Chemical Reaction Engineering & Catalysis , 13 (3): 502-511 (doi:10.9767/bcrec.13.3.2168.502-511) Permalink/DOI: https://doi.org/10.9767/bcrec.13.3.2168.502-511

We review the past development of highly sensitive and selective gold nanoparticle (AuNP)-based assays of protein and DNA biomarkers for chip-based detection systems. The microfluidic systems, various assays, and preliminary laboratory results are shown. AuNP-based biodetection assays provide low detection threshold, offering promises for multiplexed diagnostics of many forms of disease markers.

We present the design, fabrication, and characterization of a latchable microvalve. The valve can be held in the on- or off-state without consuming power. A low-melting-temperature metal alloy provides structural support to hold the valve in place when latched. The metal alloy piece liquefies when it is heated above 62degC, allowing a pneumatic actuator to change the valve state. When the metal cools and solidifies, the valve is once again latched. This type of valve may be useful for portable lab-on-a-chip devices that require low-power operation and long-term fluid storage. A thin-film metal heater has been integrated into the polydimethylsiloxane device to provide localized heating for individual valve elements. Valve closing and opening response times have been simulated and verified by experiment. The burst pressure has been experimentally characterized and parameters influencing this burst pressure have been modeled.

The topography and biocompatibility of zein layers adsorbed on patterned templates containing hydrophilic and hydrophobic regions were investigated. Nanopatterned templates consisting of hydrophilic lines on a hydrophobic background were drawn by dip-pen nanolithography (DPN) on gold-coated surfaces. 16-Mercaptohexadecanoic acid (COOH(CH(2))(15)SH, MHA) was used as primary ink to generate hydrophilic lines. Unpatterned surfaces were backfilled with 18-octadecanethiol (CH(3)(CH(2))(17)SH, ODT), which generated hydrophobic regions. Zein was allowed to adsorb on patterned surfaces from alcohol-water solutions. The topography of zein deposits was observed by atomic force microscopy (AFM). Height profiles from AFM measurements revealed that zein deposits followed closely the nanopatterned templates. The biocompatibility of zein layers assembled over hydrophilic/hydrophobic micropatterned templates was investigated. Templates containing MHA lines and ODT regions were generated by micro-contact printing (microCP). Mouse fibroblasts seeded on patterned zein layers proliferated on zein deposited over MHA lines, but not on zein over ODT. The experiment indicated that fibroblast cells were able to respond to variations in the underlying surface chemistry, transmitted by the different orientation adopted by zein on the different substrates. This property may be useful in controlling the spatial distribution of cells on patterned protein layers.

An electron beam flying near a dielectric slab plays an important part in the study of Cherenkov free-electron laser (CFEL). In this paper, an electron beam travelling along the surface of a slab made of negative-index materials (NIM) are theoretically studied. The dispersion equation with beam loaded is derived and the spatial growth rate is obtained which is proportional to the cube root of the beam current.

A novel UV absorption material of squaric acid (SA) anion (O4O42−) intercalated layered double hydroxides (LDHs) was successfully synthesized by the co-precipitation method. After intercalation, the interlayer distance of MgAl-SA-LDHs increased to 1.04 nm compared to those of MgAl-CO3-LDHs and SA anions present in form of a monolayer in the interlayer of LDHs. Thermal stability of SA clearly enhanced by the intercalation and the suppression of the deintercalation ability of MgAl-SA-LDHs was superior to that of 4-hydroxy-3-methoxybenzoic acid intercalated LDHs. The results of UV-DRS indicate the potential application of MgAl-SA-LDHs as UV absorbers.

A continuous-flow polymerase chain reaction (PCR) system with integrated heaters for DNA amplification has been designed and fabricated. A new concept of obtaining a temperature zone by natural heat conduction is presented. The finite element method is employed to analyze the temperature distribution in the DNA chip. The system is integrated through a microfluidic interconnect based on polydimethylsioxane (PDMS) material. Using oxygen RIE bonding, the PDMS interconnect can withstand a pressure up to 470 kPa. The fabrication process for the DNA chip is developed using micromachining techniques. The temperature distribution was measured. The uniformity of the denaturization temperature, annealing temperature, and extension temperature was 1.5°C/mm, 0.7°C/mm, and 3.1°C/mm, respectively. The microchannel has a width of 380 μm, a depth of 30 μm, and a total length of approximately 0.6 m. Depending on the flow rate (5 nL/s to 80 nL/ s), the 20-cycle DNA chip needs only 52 seconds to 14 minutes for thermal cycling.

This paper presents novel polydimethylsioxane (PDMS) based interconnects for microfluidic systems with a low dead volume. Through-hole type and "/spl lceil/" type PDMS interconnects have been designed, fabricated, and tested for glass and plastic capillary tubing. Oxygen reactive ion etching and epoxy bonding methods are employed to bond PDMS interconnects to different substrate materials including silicon, glass, polymer and other thin film materials. Leakage pressure, leakage rate, and pull-out force are characterized for these interconnects. For reusable PDMS interconnects, the maximum leakage pressure reaches 510 kPa (75 psi) and the maximum pull-out force is about 800 mN. For nonreusable PDMS interconnects, the maximum leakage pressure is found to be 683 kPa (100 psi) and the maximum pull-out force is 2 N. For both types of PDMS interconnects, the leakage rate test demonstrates that the leakage is not detectable at a working pressure of 137 kPa (20 psi).

Closed form analytical equations are important tools for predicting and optimizing the behavior of a piezoelectric microactuator for micropump applications. However, there is no reliable analytical solution to date to analyze the behavior of a circular piezoelectric microactuator for a valveless micropump. In this paper, a linear strain distribution is assumed across the thickness of the passive plate of the lead zirconate titanate (PZT) actuator given that the mechanical properties such as Young’s modulus and Poisson ratio of the actuator and the passive plate are close. An analytical equation for the passive plate deflection is derived upon this assumption. The analytical result shows excellent agreement with experimental data as well as the results from finite element simulation. Based on this analytical model, the effects of several important parameters and nondimensional variable groups on the actuator performance have been investigated. These parameters and variables include the dimensions and mechanical properties of the PZT disk, the passive plate, and the bonding layer material.

Controlled release formulations have been shown to have potential in overcoming the drawbacks of conventional plant growth regulators formulations. A controlled-release formulation of 1-naphthylacetic acid (NAA) and indole-3-butyric acid (IBA) simultaneous intercalated MgAl-layered double hydroxides (LDHs) was prepared. The synthetic nanohybrid material was characterized by various techniques, and release kinetics was studied. NAA and IBA anions located in the gallery of MgAl-LDHs with bilayer arrangement, and the nanohybrids particles were of typical plate-like shape with the lateral size of 50–100 nm. The results revealed that NAA and IBA have been intercalated into the interlayer spaces of MgAl-LDHs. The release of NAA and IBA fits pseudo-second-order model and is dependent on temperature, pH value, and release medium. The nanohybrids of NAA and IBA simultaneously intercalated in LDHs possessed good controlled release properties.

Aceclofenac (AC)/sulfobutyl ether-β-cyclodextrin (SBE-β-CD) inclusion complex intercalated layered double hydroxides (LDHs) composite were prepared by swelling/restoration method. After swelling/restoration, thed-spacing of LDHs is expanded to 2.23 nm, which clearly demonstrates the successful intercalation of AC/SBE-β-CD into LDHs layer. AC/SBE-β-CD inclusion complex in the interlayer has monolayer arrangement based on thed-spacing of LDHs and torus thickness of SBE-β-CD. The AC release performances were also studied in buffer solutions with different pH values. The results show AC/SBE-β-CD intercalated LDHs not only enhance the dissolution profile of AC but also exhibit a controlled-release process, which indicates that the AC/SBE-β-CD-LDHs have a potential application in drug delivery agent.