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In this study, MgAl-V2O74- LDHs/(poly(ethyleneimine)(PEI)/MXene)n composite films were synthesized via (i) in-situ hydrothermal growth of Mg-Al layered double hydroxides (LDHs) on AZ31 alloy followed by vanadate intercalation reactions, and (ii) the as-prepared MgAl-V2O74- LDHs film was covered by layer-by-layer assembly using (PEI/MXene)n, where n=5, 10, and 20. Film characterization revealed that the outer layers (PEI/MXene) were assembled on the surface by electrostatic interaction and provided a good coverage of LDHs nanosheets. But, microcracks appeared gradually on the surface and destroyed the film integrity with increasing number of PEI/MXene layers. The corrosion tests indicated that the MgAl-V2O74- LDHs/(PEI/MXene)10 composite films provided a better corrosion protection ability than that of n=5 and 20. The outer layers (PEI/MXene) had a corrosion inhibition protective effect on MgAl-V2O74- LDHs film. This work opened a new perspective of the MXene materials for anticorrosion application via a layer-by-layer assembly method.

Thermal conductivity of polymers gains much attention in many fields, and the formation of a heat conduction network is very important for polymer coatings. Carbon nanofiller is one type of excellent candidate fillers for improving thermal conductivity, but the poor incorporation between the filler and the polymer restricts coating performances. In this study, the heat transfer oil (HTO) was used as a medium to communicate the carbon nanofiller with the polymer (poly(vinylidene fluoride) (PVDF), fluorinated ethylene propylene (FEP)) and to improve the thermal conductivity and corrosion resistance of PVDF composite coatings. The micronanostructure of superhydrophobic PVDF/FEP/SiO2 (modified PVDF or m-PVDF) composite coatings was used as a storage space for the HTO, so that various carbon nanofiller including carbon nanotubes (CNTs), graphene, carbon black, and carbon nanofibers can take effect in improving thermal conductivity. Among the m-PVDF/carbon nanofiller composite coatings, the HTO/m-PVDF/CNTs coating gained the highest thermal conductivity of 0.53 W·m−1·K−1 after HTO modification, which was 3.3 times that of the m-PVDF/CNTs coating and was attributed to the connectivity of HTO. The anticorrosion of HTO/m-PVDF/CNTs was increased by 3 orders of magnitude than that of m-PVDF/CNTs owing to the synergistic effect between the HTO and CNTs in blocking the invasion of corrosive species. This research provides a unique way to design and fabricate high-thermal-conductivity composite coatings with high anticorrosion by the synergism between carbon nanofiller and HTO.

A novel sandwich-like structure material was exploited for the fabrication of an effective corrosion resistance system. An environmentally friendly composite material was synthesized by installing 8-hydroxyquinoline (8-HQ) on the surface of graphene oxide (GO). In order to prevent leakage of corrosion inhibitor 8-HQ, GO/8-HQ was modified by polydopamine (PDA), denoted as GO/8-HQ/PDA. A sandwich-like structure (GO/8-HQ/PDA) enables long-term stable storage of corrosion inhibitor in the protective matrix. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were utilized to verify the sandwich-like structure of GO/8-HQ/PDA. The electrochemical tests in a 3.5 wt% NaCl solution showed that the addition of well-dispersed GO/8-HQ/PDA into epoxy system (GO/8-HQ/PDA-EP) remarkably improved corrosion protection of AZ31b magnesium alloy compared with pure epoxy (EP) coating. The sandwich structure protects the activity and structural integrity of the corrosion inhibitor (8-HQ). The corrosion inhibitor (8-HQ) of the GO/8-HQ/PDA sandwich structure cuts off the ion exchange between the metal alloy and the electrolyte solution, which hinders the electrochemical corrosion of the metal. A possible corrosion resistance mechanism of GO/8-HQ/PDA is fully discussed. This study provides feasibilities for the immobilization of corrosion inhibitors on the metal surface.

Constructing the film with a green corrosion inhibitor is the key to metal corrosion protection. This study reports an environmentally friendly graphene oxide (GO) and carboxymethyl cellulose (CMC) composite films (CMC@GO) with enhanced corrosion protection performance. The CMC@GO composite film was grown on AZ31 magnesium alloy by the layer-by-layer (LbL) assembly method. Fourier transform infrared (FT-IR) spectroscopy and the solid-state NMR Spectrometer reveal the successful modification of CMC on the surface of GO nanosheets. The chemical states and the surface morphology of the CMC@GO composite film were obtained from X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrochemical measurements and equivalent circuit fitting results demonstrate that the film containing GO composites has higher corrosion resistance than the film of undoped GO. The CMC@GO composite film exerted the corrosion inhibition effect of GO, owing to the synergistic protective effect of GO and CMC.

In order to explore the influence of interlayer between dielectric layer and channel layer on performance of thin film transistors (TFTs), the single layer titanium doped zinc oxide (TiZO) TFTs and the dual layer indium tin oxide (ITO)/TiZO TFTs were fabricated successfully in this work. The effects of interlayer thickness on the performance of TFTs were studied and the optimal thickness condition was obtained. The experimental results indicate that the introduction of interlayer contributes to the improvement of TFT characteristics. In addition, the dual-layer ITO/TiZO TFTs also present a good uniformity, which is suitable for large-area display applications.

The general preparation method of large-area, continuous, uniform, and controllable vdW heterostructure materials is provided in this paper. To obtain the preparation of MoS2/h-BN and WS2/h-BN heterostructures, MoS2 and WS2 material are directly grown on the insulating h-BN substrate by atmospheric pressure chemical vapor deposition (APCVD) method, which does not require any intermediate transfer steps. The test characterization of MoS2/h-BN and WS2/h-BN vdW heterostructure materials can be accomplished by optical microscope, AFM, Raman and PL spectroscopy. The Raman peak signal of h-BN material is stronger when the h-BN film is thicker. Compared to the spectrum of MoS2 or WS2 material on SiO2/Si substrate, the Raman and PL spectrum peak positions of MoS2/h-BN heterostructure are blue-shifted, which is due to the presence of local strain, charged impurities and the vdW heterostructure interaction. Additionally, the PL spectrum of WS2 material shows the strong emission peak at 1.96 eV, while the full width half maximum (FWHM) is only 56 meV. The sharp emission peak indicates that WS2/h-BN heterostructure material has the high crystallinity and clean interface. In addition, the peak position and shape of IPM mode characteristic peak are not obvious, which can be explained by the Van der Waals interaction of WS2/h-BN heterostructure. From the above experimental results, the preparation method of heterostructure material is efficient and scalable, which can provide the important support for the subsequent application of TMDs/h-BN heterostructure in nanoelectronics and optoelectronics.

Development of metal-organic framework (MOF) films for selectively positioning inhibitors in metallic anticorrosion applications remains a substantial challenge due to the difficulty of controlling the arrangement of inhibitor molecules in MOF pores. Cetyltrimethyl ammonium bromide (CTAB), which contains hydrophobic and hydrophilic tails, was chosen as a prototypical inhibitor and was selectively located in the pores of the classic HKUST-1 thin film on a metallic surface. Experimental results reveal that the prepared CTAB@HKUST-1 film displays good metallic anticorrosion performances, especially for bronze conservation. A possible anticorrosion mechanism of CTAB@HKUST-1 is proposed and fully discussed. The study provides an avenue for developing MOF-based thin films for metallic anticorrosion applications to address the environmental development issues related to corrosion.

Strategies for effectively enhancing the photoreduction of CO2 have been studied for several decades. In this work, Zn2GeO4/Mg-MOF-74 composites were prepared via a hydrothermal method. The X-ray diffraction (XRD) patterns, scanning electron microscopy (SEM) images and transmission electron microscopy (TEM) images demonstrate the successful synthesis of Zn2GeO4/Mg-MOF-74 composites. The infrared spectra and TEM images indicate a close interaction between Zn2GeO4 and Mg-MOF-74, which is attributed to tetramethylammonium hydroxide (TMAOH) adsorbed on Zn2GeO4 and interacts with 2,5-dioxide-1,4-benzenedicarboxylate (H4DOBDC) from Mg-MOF-74. The CO2 adsorption isotherms illustrate that the incorporation of Mg-MOF-74 into Zn2GeO4 nanorods improved the adsorption of CO2. Only with water as the sacrificial agent, the hydrothermally prepared Zn2GeO4/Mg-MOF-74 catalyst exhibited a superior performance for the conversion of CO2 into carbon monoxide compared to that of single Zn2GeO4 or a physical mixture of Zn2GeO4/Mg-MOF-74, which is attributed to its higher adsorption capacity for CO2 and reduced recombination of photogenerated electron–hole pairs. In situ photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) further demonstrated that the Zn2GeO4/Mg-MOF-74 catalyst exhibits superior charge-transfer properties. This work may provide a useful strategy to design novel and efficient photocatalysts to reduce the atmospheric concentration of CO2.

The degradation mechanism of Ti/Pt/Au ohmic contacts to p-GaAs was identified experimentally under high direct-current density stress in detail. A revised measuring structure was designed based on the circular transfer length method (CTLM), in which the high current density of $0.8\times 10^{5}$ A/cm2 was applied vertically, while the contact resistance was measured horizontally between two contact electrodes. According to revised CTLM, the specific contact resistance was measured during stress. The results indicated that specific contact resistance showed an exponential dependence on the aging time. The depth profiling results obtained from the Auger electron spectroscopy showed that Pt penetrated into the Au layer during stress. Furthermore, some voids were observed at the Au/Pt interface, and intermixing began to form within metal layer during stress. These results demonstrated that the degradation of Ti/Pt/Au ohmic contacts to p-GaAs was attributed mainly to the electromigration and Joule heating along the current direction under high current density.

Yttrium-doped Mg-Al layered double hydroxide films (MgAlY-LDHs) were firstly fabricated by a hydrothermal method on anodized AZ31 and Mg-Y alloys. The structure, morphology, and composition of MgAlY-LDHs were characterized by X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), X-ray fluorescence spectrometry (XRF), backscattered electron spectrometer (BSE), field-emission scanning electronic microscope (FE-SEM), energy dispersive spectrometry (EDS) and glow discharge optical emission spectroscopy (GDOES), respectively. The electrochemical behavior was investigated using polarization curves, electrochemical impedance spectroscopy (EIS), and immersion tests. The results indicated that the Y ions can be successfully intercalated in the MgAl-LDH lamella by isomorphous replacement, which can enhance corrosion protective performance and possess the self-healing ability of coatings. Furthermore, the in-situ growth of ternary LDHs film on high-strength Mg-rare earth (RE) alloys demonstrated the considerable potential of anti-corrosion protection for industrial application. The schematic representation of the growth mechanism and electrochemical behavior of MgAlY-LDHs nanosheet was put forward finally.

The charge trapping effect plays a key role in multi-bit memory devices and brain-like neuron devices. Herein, MoS2 field effect transistors are fabricated, incorporating Al into host La2O3 as the gate dielectric, which exhibit excellent electrical properties with an on–off ratio in the memory window of ∼106 and a memory window ratio of ∼40%. Furthermore, the charge trapping and de-trapping processes were systematically studied, and the time constants are obtained from time-domain characteristics. Making use of the charge trapping effect, the threshold voltage of the device can be continuously adjusted. The oxide layer trap density and the interface state trap density are extracted using the charge separation method. These theoretical studies provide a deeper understanding of ways to control the charge trapping process, benefitting the commercialization of two-dimensional electronic devices and the development of new charge trapping devices.

The preparation of excellent anti-corrosion coatings is necessary for practical large-scale applications. In this study, a micro-arc oxidation (MAO) coating was prepared on the AZ31 magnesium alloy in advance. Then, on the basis of the MAO coating, the graphene oxide (GO)/MgAl-layered double hydroxide (MgAl-LDH) composite was prepared by hydrothermal chemical transformation in pure GO solution with the mixed oxide of aluminum and magnesium in the MAO coating as the endogenous cation, without introducing any kind of salts. The chemical states, structural composition and morphology of the GO/LDH-MAO coating were confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The potentiodynamic polarization revealed that 0.1 GO/LDH-MAO coating (3.89 × 10−9 A/cm2) is more resistant to corrosion than MAO coating (9.89 × 10−6 A/cm2) in 3.5 wt% NaCl solution. The organic combination of Mg Al LDH and GO can obviously enhance the corrosion protection ability of the coating. This research explored in detail the possible corrosion protection mechanisms regarding GO/LDH-MAO coatings, which supplied the feasibility for enhancing the anti-corrosion performance of MAO coating.

A very simple and facile method to synthesize Pt nanoparticles (NPs) deposited on Pt-bpy metal-organic complexes (bpy =4, 4’-bipyridyl) has been developed. No additional capping agents or solid supports are required. The formation of Pt NPs-bpy composites was largely dependent on the molar ratio of metal to bpy. When the molar ratio of Pt to bpy is more than 1:2, Pt NPs were deposited onto the surface of the formed Pt-bpy complexes. This was demonstrated by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. When the molar ratio of Pt to bpy is less than or equal to 1:2, Pt NPs are difficult to form. Moreover, the Pt NPs-bpy composites were used as a heterogeneous catalyst toward the hydrogenation reaction of the nitroarenes bearing different steric and electronic groups. The catalyst could be recycled for at least 6 cycles without catalytic activity loss.

This study demonstrated a dye-sensitized TiO 2 -polyoxometalate system (denoted TiO 2 -(PW 12 -TH) 8 , where PW 12 = PW 12 O 40 3− and TH = thionine) for selective oxidation of alcohols under visible light. The results showed that various substituted alcohols were transformed into their corresponding aldehydes with high selectivity. Due to more efficient electrons transfer, large surface area, and enhanced visible light absorption, the photocatalytic activity of TiO 2 -(PW 12 -TH) 8 was superior to any other dye-sensitized system reported to date. The response in the photocurrent-time curves over several on/off cycles of intermittent irradiation showed good reproducibility. The photocurrent response of TiO 2 -(PW 12 -TH) 8 was much higher than that of TiO 2 /TH (physical mixture of TiO 2 and TH), SiO 2 -(PW 12 -TH) 8 or P25-(PW 12 -TH) 8 (P25 = Degussa P25), attributed to the more efficient transfer and longer lifetime of photoexcited electrons. This photocatalytic process confirmed that efficient electron transfer during photocatalytic oxidation plays a vital role in determining the reaction conversion and obtaining good selectivity. Electron paramagnetic resonance (EPR) spectra and radical scavenging experiments proved that superoxide radicals and electrons were the main reactive species in the proposed system, the absence of hydroxyl radicals and holes is demonstrated to be the key of high reaction selectivity.

MXenes, a novel two-dimensional (2D) material of Ti3C2, present wide applications in energy-related fields. However, a mass of sedimentary multilayer Ti3C2 was discarded and non-recyclable due to incomplete exfoliation in the preparation of single layer Ti3C2. In this work, a composite structure, mixing MXenes/magnesium aluminum-layered double hydroxides (MXenes/MgAl-LDHs) with Y(OH)3, was synthesized in-situ as a smart coating on Mg alloy AZ31 via (i) exfoliating those multilayer Ti3C2 to few-layer MXenes (FLMs), and (ii) adding Y(NO3)3 to FLMs solution for a one-step hydrothermal treatment. Results show the electronegative mainboard of MXenes can effectively absorb cations in the reaction solution, and promote growth of MgAl-LDHs and Y(OH)3 on its surface. Moreover, MgAl-LDHs being the intermediate connector facilitate growth of MXenes upon the surface of Mg alloy AZ31. The corrosion tests indicated that the composite coating modified with yttrium had an excellent anticorrosion performance (Ecorr = −0.36 VSCE, Icorr = 9.12 × 10−9 A cm−2) and self-healing ability. Further, the formation and corrosion mechanism of composite coatings were finally proposed.

From laboratory experiments it was shown that the flashover voltage of the wet contaminated insulator was significantly influenced by the parameters of the local arc. An integrated optical and electrical diagnostic platform was designed in this paper, which was used to acquire the emission spectrum and electrical parameters of the AC local arc over the wet contaminated surface. The analysis of thermodynamic and electric results showed that AC local arc had a “static time-varying” feature. Hence, a new characterization method of volt–ampere characteristics of the AC local arc was proposed, and a time constant was introduced to describe the time required for the AC local arc to reach the stable state from the beginning. The relationship between the voltage gradient of the AC local arc and the leakage current amplitude was obtained for flashover voltage calculation. Special attention was also paid to the influence of environmental factors, such as air pressure and ambient temperature, on the arc characteristic. This work can enrich the investigation of the parameters of the local arc over the wet contaminated insulation surface and may provide useful parameters for flashover voltage calculation of insulators in service.

Fully transparent ITO/LaAlO3/ITO structure RRAM (resistive random access memory) devices were fabricated on glass substrate, and ITO/Al2O3/ITO structure devices were set for comparison. The electrical characteristics of the devices were analyzed by Agilent B1500A semiconductor analyzer. Compared with the ITO/Al2O3/ITO RRAM devices, the current stability, SET/RESET voltage distribution, and retention characteristic of the ITO/LaAlO3/ITO RRAM devices have been greatly improved. In the visible light range, the light transmittance of the device is about 80%, that of the LaAlO3 layer is about 95%, the on-off ratio of the device is greater than 40, and the data retention time is longer than 10,000 s. The devices have great optical and electrical properties and have huge application potential as fully transparent RRAM devices.

The unique porous characteristic of metal-organic frameworks (MOFs) has been attracting significant attention for gas storage, catalysis and drug delivery. However, the studies regarding loading inhibitors into MOFs for metallic anti-corrosion applications are scarcely reported. Herein, a strategy based on encapsulating corrosion inhibitors into MOFs matrix has been developed, and their corrosion process and mechanism have been fully studied. Specifically, an environmentally friendly green corrosion inhibitor, zinc gluconate (ZnG), was selected as a metal resource for the preparation of ZIF-8 and then inherently intercalated into the porous ZIF-8. Various characterizations were carried out to confirm that zinc gluconate was successfully loaded into the ZIF-8 matrix. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves show the evidence that the prepared ZnG@ZIF-8/EP coatings display good metallic anti-corrosion performances. The probably protecting mechanism of ZnG@ZIF/EP coatings for magnesium alloy surface was thoroughly discussed.

Cantilever-based sensor is kind of the most popular MEMS sensor. In this paper, by taking an example the process of analyzing a transducer is explained, such as building models and performing mathematic operations on result data to get the performance parameters of a cantilever-based sensor. We also state the principle of the cantilever bio-sensor. In the meantime we explain the theory of the operating of cantilever, and a cantilever sensor design guided by mechanical simulation.

Dry etching process are some of the most familiar MEMS technology. In this paper, we study the rate enhancements observed through operation of the power of plasma source and the oxygen flow rate in a single step at low temperature for high dose implanted photoresist removal.

The phenomenon of transient catastrophic optical damage (COD) was studied experimentally by means of thermal infrared imaging, photon emission microscope (EMMI), and electron diffraction technology (SAED) under high-resolution transmission electron microscope. We have recorded the dynamics of COD process using thermal infrared camera. The temperature of transient COD has a sudden increase of 32.07 °C when the COD event occurs which maintains less than 8.69 ms accompanying with the sudden decrease of output power. The reverse leakage current was investigated by EMMI. The leakage current of the COD sample increase and the photo in the active region was observed. Moreover, the result obtained from SAED technology identified that the silicon was changed into polycrystalline near the active area, contrasting to the silicon outside active area still remained initial single phase after COD.

A novel cantilever array sensor was micro-fabricated for precise bio-marker detection. The device was fabricated on a SOI wafer with CMOS compatible processes. In order to reducing the effect of k variation due to adsorption, a local biochemical reaction cavity was designed in the free end of the cantilever, the antibody-immobilization was performed in this local area by micro printing technology. This approach can be applied to enhance the performance of all the cantilever-based sensors. The PDMS package is designed to be used for the cantilever sensor which is greatly promoting the practicality of the sensor.

The thermomechanical stress characteristics in high-power 808-nm AlGaAs/GaAs laser diode bars were investigated experimentally and theoretically using infrared thermography and finite element method in detail. The transient thermomechanical stress curves changing with total operation current were measured using infrared thermography. The results indicated that thermomechanical stress of laser diodes chip has a logarithmical dependence on the total operation current. In addition, the dependence of thermomechanical stress on total operation current was analyzed based on finite element method which was great consistent with the experimental results. The calculated results showed that thermomechanical stress of laser diodes chip had a higher increasing rate with higher operation current density, and the plastic deformation would occur when the thermal stress reaches the yield strength.