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In this study we fabricated highly oxidized graphene oxides (GO) to reduce the optical bulk absorption, and to achieve a low-loss GO/silicon hybrid optical waveguide. The highly oxidized GO was fabricated using triple amount of oxidants and elongated oxidizing time via a modified Hummers’ method, together with post ozone treatment to effectively break down the C = C pi-conjugation network. The high oxidation degrees of GO were confirmed by a wide interlayer spacing (1.26 nm) in XRD patterns and a high fraction of oxygenated carbon (61.57%) observed in XPS spectra. Integrating a GO thin film on top of a silicon ring resonator revealed an extra optical loss of 1.2 dB/cm, while this value reduced to 0.8 dB/cm in a GO grating covered silicon strip waveguide. The resulting GO/silicon hybrid waveguide grating provided an extinction ratio of up to 35 dB at Bragg wavelength. We further demonstrated GO/silicon hybrid waveguide moire gratings to provide dual stopbands with a controllable stopband interval from 2.5 to 20 nm. All results validate the promising optical properties of such GO material for low-loss heterogeneous integration on silicon-on-insulator.

A series of BiO(OH)xI1–x solid solution (SS) catalysts were successfully prepared by ion exchange of I− and OH− between the [Bi2O2]2+ layers. The morphology and microstructure were studied in depth using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) method, etc. Tunable absorption in the visible-light region was achieved by changing the proportion of OH– to I−. Due to the etching effect of OH−, oxygen vacancies (OVs) greatly increased for the SS catalysts, and were confirmed by X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and electron paramagnetic spectroscopy (EPR). The unique composition of OH−, I−, OV, and [Bi2O2]2+ layers in BiO(OH)xI1–x materials resulted in diverse photoexcitations. The BiO(OH)0.45I0.55 photocatalyst displayed a 10-fold-improved 2-chlorophenol (2-CP) degradation rate compared to BiOI. The interfacial reaction process by the photoinduced valence-band holes and conduction-band electrons proved to be a more efficient pathway for organic pollutant degradation by the BiO(OH)xI1–x SS photocatalyst. The OVs in the SS photocatalyst facilitated photoexcited and electron migration and transformation.

Lacquer wood (LW) goes through one-step and two-step H3PO4 activation process to prepare activated carbons (ACs) at different temperature, and its performance was evaluated by testing CV, EIS, GCD and cycling respect to an electrode material in supercapacitors. The performance of lacquer wood activated carbon prepared by different activation methods and temperature (300, 400, 500, 600, 700, and 800 °C) was studied, and the influence on its electrochemical properties provides valuable guidance for the high-efficient energy utilization of lacquer wood. The results showed that the AC generated via one-step activation process at 400 °C demonstrate excellent specific surface area (SBET 1609.09 m2/g) than those from two-step activation method. Besides, the biomass-derived ACs presented overall better electrochemistry characteristic than those from charcoal-derived ACs. The largest specific capacitance (354 F/g) was obtained in the ACs-based electrodes which was generated from one-step activation process (activated at 600 °C). After 10000 cycles, its capacity retention reached 95.3%, which provides a meaningful guidance into the application of energy storage supercapacitors. This study proves that the LW derived ACs are promising electrodes of the high-performance supercapacitors, which is beneficial for value-added and industrial supercapacitors application of lacquer wood ACs.

CrAlYN coatings with different Y contents (0, 5 and 12 at.%) were deposited by cathodic arc evaporation to investigate the influence of Y-addition on the structure, mechanical and thermal properties of CrAlN coatings by using X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, thermal gravimetric analysis and nanoindentation. The structural transformation of single phase cubic Cr0.42Al0.58N and Cr0.39Al0.56Y0.05N coatings to cubic–wurtzite mixed Cr0.32Al0.56Y0.12N coating leads to a drop in hardness from (30.2±0.7) GPa of Cr0.42Al0.58N and (32.0±1.0) GPa of Cr0.39Al0.56Y0.05N to (25.2±0.7) GPa of Cr0.32Al0.56Y0.12N. The incorporation of 5 at.% Y retards the thermal decomposition of CrAlN, verified by the postponed precipitation of w-AlN and N-loss upon annealing. Correspondingly, Cr0.39Al0.56Y0.05N coating consistently exhibits the highest hardness value during thermal annealing. Nevertheless, alloying with Y exerts an adverse effect on the oxidation resistance of CrAlN.

An acoustic emission (AE) experiment was carried out to explore the AE location accuracy influenced by temperature. A hollow hemispherical specimen was used to simulate common underground structures. In the process of heating with the flame, the pulse signal of constant frequency was stimulated as an AE source. Then AE signals received by each sensor were collected and used for comparing localization accuracy at different temperatures. Results show that location errors of AE keep the same phenomenon in the early and middle heating stages. In the later stage of heating, location errors of AE increase sharply due to the appearance of cracks. This provides some beneficial suggestions on decreasing location errors of structural cracks caused by temperature and improves the ability of underground structure disaster prevention and control.

Solar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, efficient solar-driven H2O2 production through dioxygen reduction is achieved by employing polymeric carbon nitride framework with sodium cyanaminate moiety, affording a H2O2 production rate of 18.7 μmol h −1 mg−1 and an apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process is systematically analyzed, and some previously unknown structural features and interactions are substantiated via experimental and theoretical methods. The structural features of cyanamino group and pyridinic nitrogen-coordinated soidum in the framework promote photon absorption, alter the energy landscape of the framework and improve charge separation efficiency, enhance surface adsorption of dioxygen, and create selective 2e− oxygen reduction reaction surface-active sites. Particularly, an electronic coupling interaction between O2 and surface, which boosts the population and prolongs the lifetime of the active shallow-trapped electrons, is experimentally substantiated., Solar-driven H2O2 production presents a renewable approach to chemical synthesis. Here, authors perform a mechanistic analysis on the contribution of the sodium cyanaminate moiety to the 2-electron oxygen reduction reaction performance of polymeric carbon nitride frameworks.

Exfoliated and plicated g-C3N4 nanosheets (CNsF) were prepared through a thermal-chemical exfoliation in which the bulk g-C3N4 was obtained first under thermal exfoliation, and then was exposed to an acidic etching using hydrofluoric acid under hydrothermal condition. The acidic etching not only exfoliated g-C3N4 nanosheets by disrupting weak van der Waals forces between layers, which led to formation of a monolayer or a few layers of g-C3N4 nanosheets, but also made disordered defects on its surface and created plicated g-C3N4 nanosheets. Under visible-light illumination, the optimized sample (CNsF-6%) showed a hydrogen evolution rate of 54.13 μmol h−1g−1 (without co-catalyst) and a specific surface area of 121.4 m2 g−1, which were about 4.7 and 2.5 times, respectively, higher than pristine g-C3N4. It also showed remarkably enhanced photocatalytic performance in removing various organic pollutants. This remarkable improvement probably arises from the porous nanosheets and an increased number of active sites resulting from the CNsF, which subsequently enhanced the charge separation efficiency. This work provided an alternative way to obtain highly active g-C3N4 photocatalysts.

For the thin-film thermocouple with ITO/In2O3 as the functional layer, the mechanical reliability of their composite multilayer membrane structures under high temperature and random vibration conditions are discussed. Using the elastic plasticity model based on the finite element simulation method, the stress and strain distribution patterns caused by the thermal mismatch and vibration of multilayer film materials are systematically analyzed, and the distribution of the stress concentration and strain accumulation regions that may lead to fatal reliability problems are characterized. When a thermal load of 1000 °C is applied, the protective layer of the structure is vulnerable to severe stress environment. In addition, plastic deformation occurs in the adjacent layers of the functional layer, making it a weak reliability area. The stress generated by the vibration load is much smaller than the thermal stress, which mainly occurs at the roots of the structure, where prolonged loading may lead to fatigue failure.

The interchangeable operation of alkaline oxygen evolution and reduction using bifunctional electrocatalysts in devices consolidates the commercialization milestone of energy storage in hydrogen, a...

The deformation mechanism of C5191 phosphor bronze sheet under ultra-high-speed blanking was investigated. By virtue of a DOBBY-OMEGA F1 ultra-high-speed press, the ultra-high-speed blanking test was conducted on C5191 phosphor bronze sheets with a thickness of 0.12 mm at 3000 strokes per minute. The microstructures of the blanked edges were characterized and analyzed separately by electron back-scatter diffraction (EBSD) and transmission electron microscopy (TEM). The results show that grains in the blanked edges are stretched along the blanking direction. Strong {001}〈100〉 cube textures (maximum pole densities of 9 and 12, respectively) and secondarily strong {011}〈011〉 textures (maximum pole densities of 4 and 7, respectively) are formed in local zones. Additionally, deformation twins are found in the shear zone of the blanked edges which are rotated and coarsened due to the blanking-induced extrusion and local thermal effect which can further form into sub-grains with clear and high-angle boundaries. The C5191 phosphor bronze sheet is subjected to adiabatic shear during ultra-high-speed blanking, accompanied with dynamic recrystallization.

In this work, an experiment was carried out to investigate the preparation condition of anisotropic Fe-deficient M-type Ca–Sr–La system ferrite with optimum magnetic and physical properties using the raw material Fe2O3 from steel industrial iron oxide waste. The compositions of the calcined ferrites were chosen according to the stoichiometry ${\mathrm {Ca}}_{1-x-y}$ La x Sr y Fe10.9CozO19, where M-type single-phase calcined powder was synthesized with a composition of $x = 0.45$ , $y = 0.18$ , and $z= 0$ . The effect of CaO, SiO2, and Co3O4 inter-additives on the Ca–Sr–La system ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of $B_{r} = 4570$ Gauss, $_{b}H_{c} = 4320$ Oe, $_{i}H_{c} = 5260$ Oe, and ( $BH$ ) $_{\mathrm {max}}= 5.16$ MGOe were obtained for Ca–Sr–La system hard magnets with low cobalt content at 1.85 wt%. The magnetic properties of the prepared magnets really good compared to that of the traditional Sr–La–cobalt (Co) M-type ferrite, which has been the highest grade M-type hard ferrite. The remarkable steel industrial iron oxide waste Fe2O3 is recycled to produce high-end permanent magnets under an output power of < 1 kW, which will eventually be used in high-efficiency motors.

In this study, the plasma oxidation effect in tin-oxide (SnOx) thin film was investigated. And on this basis, we fabricated n-type thin-film transistors (TFTs) using the SnOx thin film with the plasma oxidation by experiments. By adjusting the processing time of the oxygen plasma treatment (OPT), the optimized SnOx TFT device exhibited an extremely high field-effect mobility of 87.6 cm2 V−1 s−1, a desirable on-to-off current ratio of 1.9 × 104 and a threshold voltage of − 0.9 V. Furthermore, we investigated the origin of the performance enhancements in the n-type SnOx TFTs with the optimized OPT by introducing the density of states (DOS) modeling in TCAD simulation. The numerical simulation indicated that the attributes of donor-like Gaussian defect states (oxygen vacancies) were modified in overall DOS due to the plasma oxidation effect. These present results show that the SnOx TFT treated by oxygen plasma has great promise in the future high-performance flat panel display industries.

Excessive energy consumption and low reaction efficiency caused by electron cycle rate limitations are bottlenecks in water treatment. Here, we introduce an innovative strategy to overcome this problem via constructing a novel three-dimensional (3D) hybrid of vanadium tetrasulfide cross-linking graphene-like carbon with π electrons (VSO–C(π)), which exhibits excellent performance during refractory pollutant removal based on sustainable electron cycling between hydrogen peroxide (H2O2), dissolved oxygen (DO), and pollutants at the solid–liquid micro-interface. VSO–C(π) is synthesized through an in situ hydrothermal synthesis procedure and characterized via a series of techniques. The cation-π structures are constructed through V–S–C(π) and V–O–C(π) bridges in VSO–C(π), triggering orientable electron transfer from C(π) to the metal V centers and forming a polarized distribution of surface electrons. In the VSO–C(π)/pollutants/DO/H2O2 system, the pollutants act as electron donors to C(π), with the subsequent degradation of pollutants, while DO and H2O2 act as electron acceptors and are activated by reactive oxygen species to further degrade the pollutants at the V centers. This sustainable electron cycling process is responsible for the excellent activity and superior adaptability to pH changes and different salt environments, while also greatly saving resources and reducing energy consumption.

In this study, we investigated the stress and doping effects of ferroelectric hafnium zirconium oxide (HfZrO) based on material analysis and electrical characteristics. The experimental results revealed that the ferroelectric crystalline phase is effectively transferred by mechanical stress of tantalum nitride (TaN) electrodes, and the origin of stress is mainly the thermal residual stress formed near the TaN and HfZrO interface. The ferroelectric polarization characteristics of HfZrO can be further modified by additional Al doping, which not only improves the leakage current of HfZrO due to the large bandgap of Al2O3 but also simultaneously stabilizes the ferroelectric domain switching under a large coercive field.

Tungstic oxide (WO3) is a promising visible-light-responsive photoanode material, but it has poor charge transport and collection properties. In this study, a WO3/BiFeO3 core/shell photoanode (WO3/BFO) with enhanced photoelectrochemical (PEC) performance was successfully prepared using a facile spin-coating method. The optimal WO3/BFO shows an excellently enhanced and stable photocurrent density of ∼2.83 mA cm−2 at 0.6 V vs. Ag/AgCl, which is ∼244% more than WO3 under AM 1.5 illumination. The results of Mott–Schottky tests, intensity modulated photoelectrochemical spectroscopy and transient photocurrent decay indicated that the BFO ferroelectric nanolayer significantly enhances the charge density of the WO3/BFO, and improves its charge transport and separation property and charge lifetime, which could be the reason for the enhanced PEC activity of WO3/BFO.

Long-term efficient separation of highly emulsified oily wastewater is challenging. Reported herein is the preparation of a reinforced superhydrophilic, underwater superoleophobic membrane with demulsification properties using active iron nanoparticles in situ generated on a polydopamine (PDA)/polyethylenimine (PEI)-modified polyvinylidene fluoride (PVDF) membrane surface. A stable zwitterionic structure is fabricated on the membrane surface and provides it with an excellent capability of binding a hydration layer, leading to enhanced superhydrophilic/underwater superoleophobic properties. The interaction between the membrane surface and water is quantified using the relaxation time of water. After iron nanoparticles in situ anchoring, the superhydrophilic, underwater superoleophobic PDA/PEI modified PVDF membrane shows more stable flux behaviors, higher oil separation efficiency, demulsification, and excellent antioil-fouling properties for various anionic, nonionic, and cationic surfactant-stabilized oil-in-water emulsions in a crossflow filtration system. The reinforced hydration layer and the amphoteric charged demusification properties of the membrane play important roles in enhancing the membrane separation performance. The reinforced membrane also exhibits excellent cleaning and reusability performance in long-term operations. The outstanding separation performance, as well as the simple and cost-effective fabrication process of the membrane with various favorable properties, highlight its promise in practical emulsified oily water applications.

W vacancies containing Bi2WO6 (VW-Bi2WO6) was synthesized by a reductant-involved hydrothermal process. The photoactivity of Bi2WO6 was enhanced by 3.3 times and the TOC removal rate increased from 38.3% to 64.7% after the introduction of surface W vacancies. Positron annihilation spectrometry (PAS), XPS, Raman spectra and other characterization results indicated that W vacancies existed on the catalyst surface. The surface W vacancies were proved to widen the band gap and negatively shift CB edge to produce more O2•− and photoexcited holes at catalyst surface, as confirmed by ESR and radicals trapping experiments. Further, according to the results of pyridine adsorbed FTIR and Zeta potentials, the enhanced interaction between pollutants and VW-Bi2WO6 was confirmed. As a result, the active species produced at surface were able to be accelerated to directly react with organic pollutants, leading to the highly efficient degradation and mineralization of pollutants in water.

Cooling shock can be considered a potential method of causing the high-temperature rocks to crack and achieve the most efficient exploitation and utilization of geo-thermal energy in the future. However, it is important to accurately recognize the thermal cracking effect and the corresponding typical characteristics of cooling shock. Therefore, in this study, we conducted a systematic experiment on the effects of cooling shocks with different temperature gradients on the cracking of high-temperature granite. The granite samples were heated to 150, 350, 550, and 750 °C, and then injected with three kinds of refrigerants of 20, 0 and − 20 °C into the granite boreholes. Furthermore, the cracking characteristics of granite were compared by means of optical microscope. According to the experimental analysis, several conclusions could be obtained: (1) Compared with natural cooling conditions, cooling shocks of 20, 0, and − 20 °C resulted in no evident open cracks on the granite at 150 and 350 °C; however, the distribution of the micro-crack networks became denser with a decrease in the refrigerant temperature. (2) For the high-temperature granite samples at 550 and 750 °C, the effect of the cooling shock was significant, and localized open cracks could be observed; however, several differences were evident in the effect of granite cracking under different combinations of cooling shocks and high temperatures. For granite with the same temperature gradient, with the decrease in the refrigerant temperature, the number of inter-granular and trans-granular cracks increased, and the cooling shock enhanced the cracking effect. (3) The main factor of granite cracking was the anisotropy of the mineral particles affected by the temperature difference, in which a large amount of quartz was contained in the granite, and the effect of repeated phase transformation near 573 °C was remarkable. Moreover, with the temperature difference between the refrigerant and the heated samples increasing, the generated tensile forces in the outer edge of samples would increase rapidly, causing amounts of trans-granular cracks and leading to the denser micro-crack networks. This work can provide an experimental reference for understanding the effect of cooling shock on mechanical properties and cracking of high-temperature rocks.

Galvanic replacement (GR) is a widely used method to obtain substrates with nanostructure morphologies. However, substantial challenges related to the uniformity of the deposited nanostructures, th...

Background Potato powder, a rich source of high-quality protein and starch, plays an important role in the production of functional foods. In this study, ball-mill processed potato powders with different particle sizes (278, 208, 129, and 62 μm) were analyzed in terms of physicochemical, pasting, rheological, and digestive properties. Results Scanning electron microscopy and laser diffraction analysis of the samples revealed mono-model particle-size distributions. X-ray diffraction analysis confirmed structure destruction of starch pellets. Proximate composition and physical property analysis showed an increase in the water, ash, protein, and starch content. Meanwhile, the water solubility index and swelling power values were found to increase with decreasing grain size, and so were the brightness (L*) and redness (b*) values of the potato powders. With particle size reduced to 129 μm, large changes were observed in gelatinization properties, such as peak viscosity, trough viscosity, breakdown viscosity, and final viscosity. Oscillatory rheology results also showed that, with the decrease in particle size, the storage modulus (G') and loss modulus (G″) improved, with highest storage modulus (G') observed in the 129 μm particle size. The hydrolysis rate and glycemic index also increased in the 129 μm potato powder. Conclusion The results provide information that could be useful for improving quality characteristics by using specific grain sizes in the development of potato-based products such as gluten-free products and ethnic food products with particular functional and rheological properties. © 2020 Society of Chemical Industry.

Sodium hypochlorite (NaClO) solution is a typical cleaning agent for membrane fouling. However, it can damage membrane chemical structures and produce toxic disinfection byproducts, which in turn reduces the membrane performance. This study focuses on the fabrication of active membranes thereby overcoming the limitations of chemical cleaning. A hierarchical active poly(vinylidene fluoride) membrane with polydopamine/polyethyleneimine (PEI) co-supported iron nanoparticle (Fe NP) catalysts was successfully constructed and denoted as a Fe-HP-membrane. The Fe-HP-membrane exhibited excellent advanced oxidation activity with maximum flux recoveries (∼85% with bovine serum albumin [BSA] and ∼95% with humic acid [HA] solutions). After the static experiment of ∼30 days, the BSA proteins and HA successfully desorbed from the membrane surface. Especially, with a trace amount of hydrogen peroxide (H2O2) flowing over the surface of the Fe-HP-membrane, highly exposed active sites were observed. Membrane cleaning showed that the "outside-to-in" active surfaces generated considerable amounts of •OH radicals at the interface of BSA or HA and the fouled membrane. As a result, the unwanted foulants were successfully removed from the membrane interface, enabling multiple use of the Fe-HP-membrane. Therefore, backwashing with a small amount of H2O2 (0.33 wt %) covered ∼20% of the flux. In contrary, backwashing with NaClO (1 wt %) can only achieve a flux recovery of ∼10% after six consecutive BSA filtration cycles. The Fe-HP-membrane exhibited better HA foulant removal (a flux recovery of ∼51%) after backwashing with H2O2 than using NaClO (a flux recovery of ∼43%). Our findings demonstrate a new platform for water treatment and regeneration of fouled membranes.

Many organic pollutants are rich in electrons, which are not used in the current pollutant removal technology, resulting in high energy consumption and low efficiency. To achieve a sustainable conversion of pollutants using Fenton-like technology, surface electron distribution-polarized lotus flower-like Fe-doped polyimide hybrid nanosheets (lf-Fe/PI HNs), a Fenton-like catalyst, are first developed for electron transfer and storage between pollutants and H2O2. Fe2+/Fe3+ ions are found in the framework of lf-Fe/PI HNs and directly bond with the C and N species of polyimide to form C–Fe–N–C in a closed loop. The experimental results and theoretical calculations demonstrate that electron-rich Fe and electron-deficient C areas are produced in the C–Fe–N–C of lf-Fe/PI HNs. This novel structure type in Fe-based materials leads to an excellent Fenton-like catalytic performance and efficiency for the refractory pollutant degradation under neutral conditions. The reaction rate is found to be 7–10 times higher than that of the conventional Fe-based Fenton-like catalyst. The reaction mechanism revealed that H2O2 is reduced to ˙OH radicals (further attacking pollutants) in the electron-rich Fe areas, and pollutants are mainly oxidized and degraded by providing electrons for the electron-deficient C areas. Fe–N–C acts as a bridge for electron transfer and electron storage carriers between pollutants and H2O2. This process enables the sustainable use of the electrons of pollutants, thereby greatly reducing the energy consumption for water treatment.

In this work, we demonstrated a HfO2-based ferroelectric field-effect transistor (FeFET) in series with a HfAlO ferroelectric capacitor for memory application and further investigated the impact of the ferroelectric capacitor with different thicknesses and areas. It was revealed that the memory window of the FeFET has a significant correlation with the ferroelectric capacitor from the transfer curves of the transistor after the series connection. By decreasing the thickness and area of the ferroelectric capacitor, the memory window of the FeFET was improved, which could be verified through the TCAD simulation tool and capacitance matching model. With the series-connected ferroelectric capacitor, in addition to optimizing the characteristics of ferroelectric memory, we can effectively avoid the interface-caused undesirable effects in conventional ferroelectric memory during film stacking. These results provide a solution for future low-power embedded memory application.

In this paper, we investigated the performance of an n-type tin-oxide (SnOx) thin film transistor (TFT) by experiments and simulation. The fabricated SnOx TFT device by oxygen plasma treatment on the channel exhibited n-type conduction with an on/off current ratio of 4.4×104, a high field-effect mobility of 18.5 cm2/V.s and a threshold swing of 405 mV/decade, which could be attributed to the excess reacted oxygen incorporated to the channel to form the oxygen-rich n-type SnOx. Furthermore, a TCAD simulation based on the n-type SnOx TFT device was performed by fitting the experimental data to investigate the effect of the channel traps on the device performance, indicating that performance enhancements were further achieved by suppressing the density of channel traps. In addition, the n-type SnOx TFT device exhibited high stability upon illumination with visible light. The results show that the n-type SnOx TFT device by channel plasma processing has considerable potential for next-generation high-performance display application.

Two-dimensional (2D) topological insulators (TIs) have attracted a lot of attention owing to their striking optical nonlinearity. However, the ultra-low saturable intensity (SI) of TIs resulting from the bulk conduction band limits their applications, such as in mode-locking solid-state lasers. In this work, through fabricating a graphene/Bi2Te3 heterojunction which combines monolayer graphene and a Bi2Te3 nanoplate, the optical nonlinearities are analyzed. Moreover, the thickness-dependent characteristics are also investigated by varying the thickness of the Bi2Te3 when synthesizing the heterojunctions. Furthermore, with the aid of the estimated junction electron escape time, a model of the photo-excited carrier-transfer mechanism is proposed and used to describe the phenomena of depression of ultra-low saturable absorption (SA) from the Bi2Te3 bulk band. The increased modulation depth of the graphene/Bi2Te3 heterojunction can accordingly be realized in more detail. In addition, a Q-switched solid-state laser operating at 1064 nm with heterojunction saturable absorbers is built up and characterized for validating the proposed model. The laser performance with varied Bi2Te3 thickness, such as pulse duration and repetition rate, agrees quite well with our proposed model. Our work demonstrates the functionality of optical nonlinear engineering by tuning the thickness of the graphene/Bi2Te3 heterojunction and demonstrates its potential for applications.

Highly active and stable electrocatalysts that can work well in alkaline media are essential for industrial water electrolysis. Herein, we have reported the growth of P and Co co-doped Ru hybrids (RuCo–P) on carbon cloth (CC) through a hydrothermal treatment and the following phosphorization. The modification of Ru by Co and P doping can tune the electronic structure for efficient water dissociation and hydrogen desorption in alkaline solution. The resulting RuCo–P/CC achieves a record low overpotential of ∼4 mV to reach a current density of 10 mA cm−2 for the hydrogen evolution reaction (HER) in 1 M KOH solution, and also shows a small Tafel slope (43 mV dec−1) and outstanding long-term stability. The activity of RuCo–P/CC is significantly superior to that of the commercial Pt/C benchmark and other carbon cloth-supported transition metal-based catalysts. The remarkable alkaline HER performance of RuCo–P/CC could be attributed to the synergistic doping of both Co and P that can effectively reduce the water dissociation barrier and optimize the hydrogen adsorption free energy, respectively.

As an important class of inorganic compounds that exhibit a variety of physical, chemical, and electrochemical properties, ABO3±δ perovskites are generally known as active electrocatalysts for the anodic oxygen evolution reaction (OER). However, the inferior performance for the cathodic hydrogen evolution reaction (HER) limits their wide potential in constructing stable oxide-based alkaline electrolyzers for hydrogen production. Here, we show that the efficient decoration of perovskite oxide (K0.469La0.531)TiO3 (KLTO) via surface ion exchange with Ru cations and nucleation growth of Ti-doped RuO2 (TRO) nanoparticles could form a composite oxide-type electrocatalyst. It enables fast water dissociation with excellent HER activity in alkaline solution, superior to other oxide electrocatalysts and commercial Pt/C. Theoretical and experimental studies imply that the co-existence of surface TRO nanoparticles and the Ru-doped KLTO (RKLTO) substrate synergistically enhances the alkaline hydrogen evolution kinetics. Ti doping into the RuO2 lattice could significantly reduce the barrier of water dissociation to facilitate the Volmer process. The surface doping of Ru in the KLTO substrate could regulate and optimize the hydrogen adsorption free energy. The present strategy represents a new concept for designing oxide-based electrocatalysts related to devices for energy conversion and storage.

Fabrication, physical modeling and dynamic response of p-type Al-doped SnOx active channel thin film transistors (TFTs) are presented for the potential application of ultra-high definition (UHD) displays. After deposition of Al-doped SnOx active layer using reactive co-sputtering, the channel was treated with plasma fluorination which improve the device performance of high ION/IOFF ratio of > 106, low subthreshold swing of ~100 mV/dec and high field-effect mobility (μFE) of 4.8 cm2V-1s-1. To understand the origin of such high performance, physical modeling and numerical simulations were performed using density of state (DOS) model of defects/traps of oxide semiconductor. This model describes the modifications of donor-like tail states and acceptor-like Gaussian defect states due to Al doping on SnOx and fluorine treatment. To evaluate the device performance for UHD large scale displays, the dynamic responses of p-type TFT pixel circuit for various requirements are simulated with physical models. These results suggest that the Al-doped SnOx TFTs are potential candidates for future high-definition displays and many applications in transparent electronics.

Transparent electronics has attracted much attention and been widely studied for next-generation high-performance flat-panel display application in the past few years, because of its excellent electrical properties. In display application, thin film transistors (TFTs) play an important role as the basic units by controlling the pixels. Among them, oxide-based TFTs have become promising candidates and gradually replaced the conventional amorphous and polycrystalline silicon TFTs, due to high mobility, good transparency, excellent uniformity and low processing temperature. Even though n-type oxide TFTs have shown high device performance and been used in commercial display application, p-type oxide TFTs with the equal performance have been rarely reported. Hence, in this paper, recent progress and challenges in p-type oxide-based TFTs are reviewed. After a short introduction, the TFT device structure and operation are presented. Then, recent developments in p-type oxide TFTs are discussed in detail, with the emphasis on the potential p-type oxide candidates as copper oxide, tin oxide and nickel oxide. Moreover, miscellaneous applications of p-type oxide TFTs are also presented. Despite this, the performance of p-type oxide TFTs still lags behind, as compared with that of n-type counterparts. Thus, the current issues and challenges of p-type oxide TFTs are briefly discussed.

Optimal device integrity was achieved in Ni/SiGeOx/TiOy/TaN resistive memory by using a forming-free switch with a low switching power of 790 μW, stable endurance of 104 cycles, optimal retention time of 105 s, resistance window of at least 1150×, and tight current distributions at 85 °C. These characteristics are attributed to the low current switching obtained using SiGeOx with a high oxygen vacancy density and highly defective TiOy grain boundaries.

The solid-solid or solid-liquid interfaces are vital for the photocatalytic reaction. Herein, AgI nanoparticles (NPs) attached on the (0 1 1) plane of Ag2WO4 nanorods were synthesized by a facile method at room temperature. The co-crystalization of the two components caused their phase transformation and the existence of a strong interface interaction. Meanwhile, the porous batt-like morphology of AgI NPs provided more contact sites for organic pollutants to induce a strong interaction at the solid-liquid interface. The heterojunction nanocatalyst was found to be highly effective for the degradation and mineralization of various pollutants, including the endocrine-disrupting chemical bisphenol A, the antibiotics sulfamethoxazole and ciprofloxacin, and the azo-dye methyl orange under visible light (λ > 420 nm). Its photocatalytic rate was 91, 52, and 39 times higher than that of bulk AgI, standard TiO2-xNx, and the physical mixture of the two components, respectively. Further studies demonstrated that the strong interactions between the two components and the pollutants promoted the electron transfer from organic pollutants to AgI NPs and then from AgI NPs to Ag2WO4 nanorods, resulting in the rapid oxidation of pollutants and the formation of Ag NPs. The newly formed Ag NPs further accelerated the degradation of pollutants due to a SPR effect and an empty levels feeding role to produce h+ on Ag2WO4, which can oxidize surface-adsorbed H2O into OH. This photocatalytic system provided a platform for understanding solid-solid and solid-liquid interface interaction and a novel design idea for water pollutants removal.

Nanoscaled Ti1-xSixN/CrAlN multilayers combining the cutting edges of Ti1-xSixN and CrAlN coatings are currently the focus of attention of researchers. Here, the structural, mechanical, and thermal properties of Ti1-xSixN/CrAlN multilayers with varied Si content were investigated. The hardness values of Ti1-xSixN/CrAlN multilayers are individually enhanced to 30.7 ± 1.0 GPa for x = 0, 36.0 ± 1.3 GPa for x = 0.13, and 35.9 ± 1.5 GPa for x = 0.22 from the 27.4 ± 0.3 GPa for CrAlN due to interfacial strengthening effect. Ti1-xSixN insertion layers retard the thermal decomposition process of CrAlN. After annealing at 1200 °C, the hardness of Ti1-xSixN/CrAlN (x = 0, 0.13, 0.22) multilayers is individually enhanced by ∼6.9, 12.9 and 13.6 GPa from the 18.7 ± 1.1 GPa for Cr0.32Al0.68N. However, Ti1-xSixN insertion layers lead to a drop in the oxidation resistance of CrAlN coatings due to their inferior oxidation resistance. Noticeable is that increasing Si content of Ti1-xSixN/CrAlN multilayers causes a decline in the thickness of oxide scales.

In this paper, the effect of channel annealing and oxygen flow rate in P-type tin-monoxide (SnO) thin film transistor (TFT) was investigated to reach the process compatibility with n-type oxide-based TFT. The optimized P-type SnO TFT with a small threshold voltage of -0.1 V, a high field-effect mobility of 4 cm² V-1 s-1 and an on/off current ratio of >10² was proposed. From the experimental results, the 150 °C channel annealing revealed a metallic behavior but a semiconductor-like property at a higher 200 °C that was favorable for transistor rectification. Besides, the higher oxygen flow rate was also helpful for improving device mobility and driving current, but shows a slight increase in off-state leakage, which is unavoidable due to the increase of grain in SnO channel.

Significant heat generation in modern high-speed electronic devices requires elevated thermal conductivity of electrically conductive adhesives (ECAs), but the gap between discrete filler materials...

In this study, the effect of the grain boundary density on the transport properties of the Re-substituted higher manganese silicide Mn30.4Re6Si63.6 has been investigated. The efficiency of electric...

In this work, we successfully demonstrated the 9.6-nm-thick HfAlOx ferroelectric memory using light aluminium doping of 6.5% to form ferroelectric orthorhombic phase. Compared to ferroelectric HfZrOx film with zirconium diffusion issue, the HfAlOx film showed excellent thermal stability under high temperature annealing. Besides, the ferroelectric HfAlOx also exhibited robust polarization characteristics under endurance cycling test. A >106 stressed cycles with 4 MV/cm can be measured and a long endurance was sustained over 5 × 107 cycles under 3.6 MV/cm. Therefore, the HfAlOx film showed the great promise for integrating in high performance ferroelectric memory with thermal budget concerns.

A visible-light-driven photocatalyst nitrogen-deficient mesoporous graphitic carbon nitride (mpg-C3N4-δ) was prepared by a thermal polymerization-assisted colloidal crystal templating method. The unique mesoporous structure of mpg-C3N4-δ was confirmed to be formed with relatively uniform pores and cyano groups ( C N)-related nitrogen defects, which were generated from the break of the C N bonds of triazine rings and the subsequent loss of terminal NHx species during the pore-making process. Benefiting from the larger surface area, suitable energy level and increased unpaired electrons on C atoms of aromatic rings, the photocatalytic activity of mpg-C3N4-δ for RhB degradation was 11 and 2.6 times higher than that of bulk g-C3N4 and mpg-C3N4, respectively, under visible light irradiation (λ ≥ 420 nm). Furthermore, nitrogen defects in mpg-C3N4-δ were verified to serve as electron/hole traps to boost the separation and transfer of photoexcited charge carriers and thus enhanced the production of main active species h+ and O2 −, resulting in the efficient destruction of the intrinsic structure and functional groups of RhB molecules into small molecules. This work highlights that construction of uniform mesoporous architectures with surface nitrogen defects could be useful for developing highly efficient metal-free photocatalysts.

Ag/Ta2O5/CuO/Pt memristive devices with Ag point contacts at the interface exhibit forming-free and partial volatile analog resistive switching properties. Versatile synaptic functions, like the short-term plasticity, the long-term potentiation and the paired-pulse facilitation, are emulated with these devices. The Ag point contacts in the Ta2O5 layer are verified through transmission electron microscope (TEM) and X-ray photoelectron spectroscope (XPS). The Ag point contacts at the interface endow the device the transition from the electrochemical metallization mode to the valence change mode, and the analog resistive switching behavior and neuromorphic functions. This interface engineering of introducing point contacts at the interface provides a way for the development of neuromorphic devices with low power consumption. Keywords: Artificial synapse, Memristive device, Ag point contacts, Short-term plasticity, Long-term potentiation

Consumption of additional H2O2 is necessary in classical Fenton catalysis. Herein, we report a novel and special nanocatalyst consisting of CoMoS2 nanosphere-embedded, reduced graphene oxide (rGO) nanosheets (CMS-rGO NSs). This nanocatalyst was discovered to have an impressive reactivity for in situ generation and synchronistical activation of H2O2 in different active centers, yielding fast and efficient degradation of the pollutants. The reaction rate is ∼21 times higher than that of conventional Fenton catalysts. The characterization shows that countless flower-like CoMoS2 nanospheres are uniformly embedded in the rGO nanosheets through Mo S C bonding bridges in CMS-rGO NSs, which leads to activation of the π electrons and their transfer from rGO to the metal centers (π → M). The formed Mo O Co further leads to a distribution of orientations of the electrons around the metal centers due to the different electronegativity of Mo and Co. During the reaction, the dissolved O2 is efficiently reduced to HO2 /O2 − around the electron-rich Mo center, and HO2 /O2 − is further reduced to H2O2 around the Co center. The generated H2O2 is finally reduced to OH for degrading dyes in the electron-rich metal (Mo or Co) centers of CMS-rGO NSs. The dye pollutants also act as electron donors, and they are directly degraded in the electron-poor π-center of CMS-rGO NSs, which promote the electron transfer cycle and achieve electron gain-loss balance. This discovery provides a new strategy for H2O2 generation-activation and pollutant degradation through constructing electron transfer bridges over the surface of catalysts.

A powerful technique to detect bone biomarkers has been developed for assessment of osteoporosis at the early stage. Two-dimensional multilayered gold-nanoparticle thin film (MTF-AuNPs) was demonstrated as a promising test platform for detection of bone biomarker, hydroxyproline (HYP), measured by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). With strong surface plasmon resonance and excellent homogeneity, facilely prepared, highly ordered, and large-scale MTF-AuNPs revealed high sensitivity of HYP in the SALDI-MS measurement without additional matrixes, such as α-cyano-4-hydroxycinnamic acid (CHCA) and 2,5-dihydroxybenzoic acid (DHB). Furthermore, the mass spectrum of HYP with MTF-AuNPs was significantly improved in signal intensity enhancement, background noise reduction, and signal-to-noise ratio amplification. The excellent reproducibility of HYP spectra with only 9.3% relative signal variation could be attributed to MTF-AuNPs’ high absorbance at a wavelength of 337 nm, low heat capacity, superior thermal conductivity, and outstanding homogeneity. The calibration curve showed high linear correlation between mass spectrum intensity and HYP concentration in the range of 1 to 100 μM, covering the whole level in healthy people and osteoporosis patients. In particular, the serum sample was directly deposited onto the MTF-AuNP sample substrate without any pretreatment and its HYP concentration was then successfully determined. We believe that the combination of SALDI-MS and MTF-AuNP sample substrates would be a potential approach for bone biomarker detection in the osteoporosis risk assessment.

With experimental and numerical simulation, we report the origin of the performance enhancement in p-type SnO thin-film transistors (TFTs) due to fluorine plasma treatment (FPT). To study the effect of fluorination, using the reactive-ion-etching process, the devices are treated at various plasma powers upto 60 W. It is observed, through X-ray photoelectron spectroscopy and XRD measurements, that the plasma fluorination modifies the defect/trap states of SnO channel and SnO/HfO2 interface. These effects are introduced through density of state (DOS) model for SnO in numerical simulations, to understand the routes of electrical performance improvement. It is observed that the attributes of donor-like band-tail state and acceptor-like Gaussian defect states (Sn vacancies) are modified in overall DOS due to plasma fluorination. The treated device shows excellent electrical performances with high ${I}_{ \mathrm{\scriptscriptstyle ON}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ ratio of ~107 and low substhreshold swing of ~ 100 mV/dec and field-effect mobility ( $\mu _{\text {FE}}$ ) of 2.13 cm2V−1s−1.

In this paper, we reported a ferroelectric HfAlO x negative capacitor transistor with gate-stress (GS) engineering. Compared to control device, the HfAlO x transistor with GS engineering percentage of $\text{I}_{ \mathrm{\scriptscriptstyle ON}}$ enhancement and 27% $\text{V}_{T}$ reduction under the assistance of the negative capacitance (NC) effect. The orthorhombic phase transition played a crucial role in realizing the NC effect. From the results of the material analysis, the theoretical Landau simulation and electrical measurement, we demonstrated that the GS is favorable for inducing orthorhombic phase crystallization of HfAlOx and stabilizing the NC effect, which shows the potential for the application of advanced technology node.

The heterogeneous Fenton process suffers from low efficiency because of the low electron transfer cycle rate of Fe3+/Fe2+, which often consumes enormous amounts of hydrogen peroxide (H2O2) or other energy. Herein, we report a novel Co-based Fenton-like catalyst (in-situ-Co-g-C3N4) synthesized via the surface complexation method, in which Co species were modified in situ into the framework of the graphitic carbon nitride (g-C3N4) substrate through C–O–Co chemical bonding. The catalyst exhibited higher Fenton-like catalytic activity than pure g-C3N4 in the degradation of various pollutants under neutral conditions, as evidenced by the approximately 150-fold higher Fenton-like reaction rate constant of in-situ-Co-g-C3N4 than that of g-C3N4. Density functional theory (DFT) calculations and a series of experimental and characterization analyses revealed the interfacial reaction mechanism between H2O2, pollutants and in-situ-Co-g-C3N4. During the Fenton-like reaction, the electron-poor C center on the aromatic ring of g-C3N4 could capture the electrons deprived from pollutants, and subsequently deliver them to around the electron-rich Co center to efficiently reduce H2O2 to hydroxyl radicals (•OH), enabling H2O2 to be used efficiently for the degradation of pollutants. This study provides a strategy for improving Fenton-like degradation efficiency by effectively utilizing the energy of organic pollutants.

In this paper, we reported ap-channel tin-oxide (SnO) thin-film transistor (TFT) by introducing aluminum (AI) dopant in the SnO channel layer. An extremely high field-effect mobility $(\mu_{\text{FE}}$ ) of 8 cm2/V·s and an on-to-off current ratio $(I_{\text{on}}/I_{\text{off}})$ of ~103 were obtained in this p-channel Al-doped SnO (A1:SnO) TFT. Furthermore, the device performances of the Al:SnO TFT including the $I_{\text{on}}/I_{\text{off}}$ and subthreshold swing (SS) were greatly improved by fluorine plasma treatment (FPT) on the Al:SnO channel layer. In addition, in order to study the channel plasma effect on the device performances, TCAD simulation was carried out based on the p-channel Al:SnO TFT by introducing the density of state (DOS) model. The simulation results indicated that the device performance enhancements were further achieved because the attributes of acceptor-like Gaussian defect states and donor-like band-tail state were modified during the FPT.

In this study, the preparation and magnetic properties of Ca–Sr M-type (Ca1-x-yLaxSryFe10.9CozO19) ferrire magnets were investigated. A M-type singlephase calcined powder was synthesized with a composition of x ​= ​0.45, y ​= ​0.18 and z ​= ​0. And a very high magnetic properties of Br ​= ​5425Gauss and iHc ​= ​4602Oe were obtained by the thermal annealing and secondary fine-milling method in the sintered magnets. The magnetic properties greats exceeds that of traditional Sr–La–Co M-type ferrite, which has been the highest grade M-type hard ferrite. By use of the innovative post-processing method, the improvement could be attributed to about 4% and 0.8% increase in motor torque and motor efficiency in comparison to that of conventional process, which will eventually be used in high-efficiency motors.

The microstructure and microtexture of TC4-DT alloy before and after quasi-β heat treatment are investigated, as well as the influence on the acoustic behaviors of ultrasonic inspection. C-scan ultrasonic images are obtained to investigate the evolution of microstructure confirmed by metallography and electron backscatter diffraction (EBSD) analysis. Noise level and signal-to-noise ratio (SNR) of ultrasonic inspection are also quantitatively verified. The results show that when TC4-DT alloy undergoes quasi-β heat treatment, attenuation and scattering of acoustic energy is significantly different. During this process, the scattering mechanism of acoustic changes from Rayleigh scattering to Phase scattering, which is mainly controlled by the grain size. Under the same scattering mechanism with the uniform average grain size, however, the regions of a-phase crystallites with a certain orientation contribute to the scattering of the acoustic wave. This finding is helpful for estimating ultrasonic inspection ability of large components.

Humidity sensors are prone to condensation in high humidity and low temperature environments, reducing the sensor's measurement performance. Aiming at the current humidity sensor heating system that may not reach the target temperature due to open-loop control and high power consumption, a closed-loop control heating system for the humidity sensor is designed to perform real-time heating and temperature detection of the humidity-sensitive structure. The finite element analysis method is used to conduct thermal analysis on the heating structure, which obtains the temperature distribution of the sensor heating area, guides the heater structure design and gains the location distribution of temperature sensors. A variable parameter fuzzy PID (Proportion Integration Differentiation) control method with variable target temperature is proposed to perform closed-loop control on the temperature of the sensor’s sensitive structure. The heating target temperature is set as a function of the ambient temperature. Also the coefficient of PID changes with error. Thus, the power consumption of the system has been effectively reduced and the heating speed is apparently increased. Simulation experiments show that the heating system designed for controllable heating humidity sensor has uniform temperature distribution. When the ambient temperature is −70°C, the difference between upper and lower temperatures is only 0. 0878°C, with a low power consumption (5 × 106W/m3). At the same time, the overregulation of the temperature control system is low, which is 7. 227%. The system has high environmental adaptability and temperature stability.

SummarySolar-driven hydrogen peroxide (H2O2) production presents unique merits of sustainability and environmental friendliness. Herein, highly efficient solar-driven H2O2 production through the reduction of dioxygen coupled with the oxidation of biomass-derived glycerol as a sustainable reductant was achieved by employing an unusual p-type polymeric carbon nitride (PCN) framework with sodium cyanaminate moiety (PCN-NaCA), which exhibited a highly enhanced production rate of 15.0 mmol H2O2 h−1 g−1(catal.) and a notable apparent quantum yield of 27.6% at 380 nm. The overall photocatalytic transformation process was systematically analyzed using various static/time-resolved spectroscopic and computational methods. The presence of sodium cyanaminate moiety in PCN-NaCA induced the following multiple effects: enhancing photon absorption, switching to p-type character with accumulating more electrons in the surface region, retarding radiative charge recombination, enhancing surface adsorption of O2, and favoring highly selective 2e− ORR. In particular, it was found that the adsorption of O2 (an electron acceptor) on PCN-NaCA actually enhances the population and lifetime of trapped electrons in the ps-ns time regime, which should have a notable synergic effect on oxygen reduction process. All of these unique properties of PCN-NaCA positively contribute to the extraordinary photoactivity of H2O2 production.

In the present article, we report a novel colorimetric probe (TNT@MB) for the detection of the phosphate ion, which is based on the strong binding affinity between the phosphate ion and titanium dioxide nanotubes (TNTs). TNTs were synthesized from TiO2 nanoparticles by hydrothermal treatment. The obtained TNTs had an average length of 200 ± 50 nm and an average width of 12 ± 5 nm. TNT@MB was prepared by adsorbing methyl blue onto TNTs in acidic condition. The optimal synthesis conditions for TNT@MB consisted in having 0.05 g of TNTs react with 1 μmole of methyl blue at pH 2 for 90 min. TNTs and TNT@MB were characterized by UV–vis diffuse reflection spectroscopy, TEM, FTIR, and XPS. The phosphate-ion sensing behavior of TNT@MB was investigated by UV–visible spectroscopy. The phosphate-ion concentration linear range and detection limit of this method based on TNT@MB were 1–40 μM and 0.59 μM, respectively. A sample of lake water was used as a real sample, and analyte recovery rates were measured in the 102.5–103.6% range, with relative standard deviations below 5.6% (n = 3). We also found that this probe could be reused after regeneration in alkaline solution. These results indicate that as a colorimetric probe, TNT@MB has the advantages of being environmentally friendly, inexpensive, and simple to use, as well as giving rise to an easily observable color change.