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White light-emitting diode (WLED) has been widely used because of its excellent performance in solid-state lighting. Among all the white LEDs (WLEDs), the phosphor-converted WLED is the most popular one, and its performance depends on the characteristics of the phosphor to a great extent. For this reason, it is necessary to study new phosphors for their potential use in WLEDs. In this thesis, a new garnet CaEr2Mg2Si3O12 matrix for phosphors was prepared by a solution combustion synthesis. Parameters of the synthesis, such as fuel-to-oxidizer ratio, amounts of precursors, order of mixing, as well as combustion and calcination parameters were optimized during this process. The garnet structure was successfully obtained and confirmed by X-ray diffraction characterization technique.

Inorganic fibers and opacifiers are indispensable for improving the strength and high temperature insulation performance of the fumed silica-based thermal insulation material. However, zirconia fiber enhances the strength of the fumed silica-based thermal insulation material and reduces the radiative heat transfer to replace the opacifier. The sample of fumed SiO2/Al2O3 doped with 7% zirconia fiber (FZ7) has a lower density of 0.70 g/cm3 and a high porosity of 75.0%. In addition, the thermal conductivity of FZ7 at 800 °C is 0.077 W/(m·K), which is lower than the sample of fumed SiO2/Al2O3 doped with 7% glass fiber (FG7) and 0.089 W/(m·K) at 800 °C. The effective extinction coefficient of the thermal insulation material containing zirconia fiber is larger than that of the glass fiber by Fourier transform infrared spectroscopy analysis and calculation, indicating that the zirconia fiber has a distinct absorption and scattering effect on infrared radiation to reduce the radiative heat transfer. Therefore, zirconia fiber enhances the strength and decreases the high temperature thermal conductivity of the composites with the dual effect on the insulation and mechanical performance of the fumed silica-based thermal insulation material.

SiOC as an alternative silicon-based material possesses great potential in lithium ion batteries due to its high reversible capacity, tunable chemical component and various synthetic route. However, large-scale production of SiOC powders grinded from SiOC bulks is restricted in commercial application because of the poor electrical conductivity. Herein, three dimensional (3D) lamellar SiOC@C/rGO composite is fabricated through hydrothermal reaction and electrostatic self-assembly process, in which SiOC powders encapsulated by amorphous carbon layers are homogeneously dispersed in graphene sheets. Cfree nanoclusters in SiOC, carbon layers on SiOC surface and graphene supporters in the composite establish the multidimensional interconnected conductive architecture and possess favorable interfacial adhesion. Therefore, SiOC@C/rGO exhibits high specific capacity (676 mAh g−1 at 200 mA g−1) and remarkable rate capability (306.4 mAh g−1 at 4000 mA g−1). The full cell assembled with this anode and LiFePO4 cathode also demonstrates stable voltage platform and good performance for 200 cycles. The excellent performance of SiOC@C/rGO profits from the synergistic effect of robust construction, multidimensional conductive architecture and chemical. Composition The proposed strategy can also be developed to prepare other materials with graphene layer to enhance their electrical conductivity for commercial application.

Mesoporous SmMnO3/CuMnOx catalyst was prepared by a two-step method using flaky CuMnOx with high specific surface and excellent catalytic ability as the carrier, which was further applied to photothermal synergistic degradation of gaseous toluene. Quantitative analysis of O2-TPD and H2-TPR showed that SmMnO3/CuMnOx exhibited abundant of the surface oxygen species and oxygen vacancies content, which enabled it to convert free oxygen to lattice oxygen more quickly during the reaction, and thus improving the reaction process. I-t and photoluminescence experiments demonstrated the improvement of photogenerated electron and hole separation ability of SmMnO3/CuMnOx catalyst. UV–Vis analysis manifested the full spectral range of absorption. XPS analysis verified the unequal positions of valence band of the two materials, which can facilitate the separation of photogenerated electrons from holes and improve the ability of better electron transfer. SmMnO3/CuMnOx catalyst has higher adsorbed oxygen content and light absorption capacity, which is beneficial to the catalytic oxidation. In situ DRIFTs proved that the oxidation reaction on the catalyst followed the Mars-van Krevelen redox cycle. The VOCs test found that SmMnO3/CuMnOx composite catalyst is with lower onset reaction temperature (T90 = 190 °C, T90, corresponding to 90% conversion) and good mineralization (100% at 275 °C).

The suitable powder flowability is critical to the success of powder spreading processes in powder-bed additive manufacturing (AM). There are several methods to test powder flowability, but the powder flowing is more complex in spreading processes and cannot be fully characterized with any single test method. Twelve kinds of powders which are widely used in AM are considered, and their flowabilities are measured. Besides the size and shape features of powders are described, the compressibility, shear and dynamic flow energy indexes of powders are measured by a FT4 powder rheometer. A comprehensive evaluation index (CEI) for evaluating powder flowability is proposed based on the principal component analysis of the test results, and reveals the impacts of powder surface modification and gradation on powder flowability. The CEI has a stronger correlation with the avalanche angle during powder spreading processes than other indexes, which is suitable to evaluate powder flowability in AM.

The sinterability, microstructure, and mechanical properties of pure TiB2- and CrB2-doped ZrB2 prepared by spark plasma sintering were investigated. The solid solutions were synthesized by the complete borothermal reduction to form (Zr0.95Ti0.05)B2 and (Zr0.95Cr0.05)B2. The results showed that the solid solution of (Zr0.95Ti0.05)B2 yielded the smaller particle size than that of (Zr0.95Cr0.05)B2. The sinterability was also improved with the use of the solid solutions, as evidenced by an increase of relative density but at the cost of coarsened microstructure. Overall, (Zr0.95Cr0.05)B2 possessed significantly higher relative density and Vickers hardness than ZrB2 and (Zr0.95Ti0.05)B2.

Bilayer graphene (BLG) grown via chemical vapor deposition (CVD) tends to exhibit twisted stacking. The twist angle θ t in twisted BLG (tBLG) provides a new degree of freedom for engineering its electronic and optical properties. In this paper, we investigate the θ t-dependent optical absorption in tBLG and deeply understand the electronic structure-optical properties correlations. New absorption peaks, whose wavelengths are modified by θ t, are observed on the feature of optical contrast (OC) in tBLG. Under the corresponding energy excitation, the Raman G mode in tBLG exhibits a significant enhancement. Furthermore, the results of θ t obtained by OC absorption peak are verified to be consistent with those by the Raman R mode. All these properties are proved to be related to the energy difference between low-energy Van Hove singularities (E VHS) in the density of states of tBLGs. This work builds a relation between optical absorption and twist angle, providing a viable method to identifying twist angles in tBLGs.

Co3O4-Ni-MOF composite was successfully prepared by solvent-thermal method and then was combined with acidified multi-walled carbon nanotubes (MWCNTs); the resulting Co3O4-Ni-MOF/MWCNTs hybrid was applied in supercapacitor and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). The electrochemical tests including cyclic voltammetric (CV), galvanostatic charge and discharge (GCD), electrochemical impedance spectroscopy (EIS), and cycle life were also performed to investigate the supercapacitor properties of the as-prepared materials. The experimental results show that when the molar ratio of metal oxide material and Ni-MOF material is 1:1, Co3O4-Ni-MOF material displays better electrochemical performance. As the mass ratio of Co3O4-Ni-MOF and MWCNTs is 1:1, Co3O4-Ni-MOF/MWCNTs hybrid exhibits lower Rct value, higher cyclic capacitance stability, and better supercapacitor performance. Therefore, Co3O4-Ni-MOF/MWCNTs hybrid as an electrode material has a relatively ideal application prospect in terms of supercapacitor materials.

The growing demands for optical anti-counterfeiting technology require the development of new environmentally friendly materials with single component, multimodal fluorescence and high stability. Herein, the Bi/Sb codoped Cs2Ag0.1Na0.9InCl6 lead-free double perovskite material is reported as an efficient multimodal luminescence material with excitation-wavelength-dependent emission. When excited by 360 nm UV light, dual-emission is observed at 455 and 560 nm, which comes from the 3P1-1S0 transition of Sb3+ ions and self-trapped excitons (STEs), respectively. Under the 320 nm UV lamp, the microcrystals show only a blue emission centered at 455 nm. Therefore, the Bi/Sb codoped Cs2Ag0.1Na0.9InCl6 double perovskite emits blue and yellow lights under the 320 and 360 nm UV lamp, respectively. Moreover, the obtained double perovskite shows a high PLQY up to 41% and excellent stability against both air and high temperature, which make it a promising anti-counterfeiting material.

Carbon-carbon composites are widely used in thermal management, photocatalysis, aerospace, high-speed railway, and nuclear energy applications, owing to their low density, high temperature stabilit...

Diffusion bonding was successfully applied to join 304 stainless steel (SS) and tungsten (W) using interlayers of Cu and Ni, and the effect of bonding temperature on microstructure and strength of 304SS/Cu/W and 304SS/Ni/W joints is investigated. The present study shows that a sound 304SS/Cu/W joint with sufficient mutual diffusion across 304SS/Cu and Cu/W interfaces is obtained at a bonding temperature of 1000 ℃, in which solid solutions occur at Cu/W interface. The 304SS/Cu/W joint bonded at 1000 ℃ shows the highest shear strength of 277.2 MPa and good ductility. The occurrence of cracks at 304SS/Cu interface with the increasing of bonding temperature results in the decrease in shear strength of 304SS/Cu/W joints under brittle fracture. The 304SS/Ni/W joints are free of crack in the bonding temperatures of 850 ℃–1000 ℃, which shows the highest shear strength of 237 MPa bonded at 950 ℃ due to occurrence of intermetallic compound Ni4W in the diffusion layer close to Ni/W interface. No obvious diffusion layer at 304SS/Ni/W is observed following bonding at 850 ℃ and 900 ℃. The micro-voids in the diffusion layer bonded at 1000 ℃ are responsible for the lower shear strength of joint than that of 950 ℃.

The pesticide residues have become one of the issues in the fields of environmental health and food safety. Herein, an effective method was successfully developed to rapidly determine imidacloprid in environmental water samples based on magnetic molecular imprinted polymers (MMIP) coupled with high-performance liquid chromatography. MMIP were creatively synthesized in one-pot synthesis step via the nucleation process of Fe3O4 magnetic nanoparticles and the polymerization process of molecular imprinted polymers simultaneously, using imidacloprid as template and dopamine as functional monomer. The parameters effected on the extraction efficiency, including pH value and the amount of the adsorbent, have been optimized. Under the optimal conditions, MMIP was used to extract imidacloprid in water samples with excellent recovery (88–97.3%) and precision (1.2–3.3%). Therefore, magnetic nanoparticles-based dispersion solid-phase extraction could be a good candidate for highly efficient extraction of imidacloprid without complicated operations.

Wave rotor refrigeration is a new method of expansion refrigeration. Non-equilibrium phase transition is one of the key factors that influence the refrigeration performance of wave rotor. Since the process of phase transition is transient and high-frequency, there are challenges in related researches. At first, this paper traces the movement trajectory of small particles in wave rotor and confirms the existence of evaporation in wave rotor. Based on this, the numerical analysis model of wave rotor that takes into account the phase transition regarding evaporation as reverse process of condensation is built up. On this basis, the change of droplet radius, droplet number and liquefaction fraction in wave rotor is obtained. Besides, the influence of inlet pressure and humidity on refrigeration performance of wave rotor is found out. The results show that with the increase of pressure of HP inlet, the isentropic expansion efficiency increases and the increase becomes gentle. With the increase of relative humidity of HP inlet, the efficiency decreases and the decrease reaches 2.8% at maximum. The results can help optimize wave rotor performance and be used for reference to wet gas transient temperature change.

Aiming at reducing the energy absorption of the hydrogen cylinder for fuel cell vehicles in collision, which may lead to fierce explosion, this paper introduces an energy-absorbing protective shell combining with negative Poisson’s ratio (NPR) structure to the hydrogen cylinder. It adopts three honeycomb structures of the same mass and three kinds of aluminum alloy to determine the optimal structure and material scheme of the protective shell. Besides, sensitivity analysis is selected to screen the design parameters of the optimal structure scheme. Based on this, the overall mass of the designed protective shell, the specific energy absorption of NPR structure, the maximum impact force of rigid wall, and the maximum stress of the liner are taken to establish the optimization mathematical model. Furthermore, adaptive mutation genetic algorithm (AMGA), non-dominated sorting genetic algorithm-ii (NSGA-II), and adaptive simulated annealing algorithm (ASA) are exerted as the optimization algorithms separately to conduct optimization design and a comparison is made between the optimization results. The results show that the optimized energy-absorbing protective shell has better crashworthiness and energy absorption effect, which can effectively improve the collision safety of the hydrogen cylinder. It provides a new idea for the protection design of hydrogen storage system in fuel cells in the future.

To obtain the excellent permeate flux, rejection performance and mechanical properties, the chlorinated polyvinyl chloride (CPVC) porous membrane was fabricated on the polyethylene terephthalate (PET) non-woven fabric by non-solvent induced phase separation (NIPS), using Tween80 (polyoxyethylene sorbitan monooleate) as a hydrophilic surfactant to regulate the microstructure of the membrane. Porous skin layer and sub-layer were achieved when 3 wt.% Tween80 was added with a small amount of deionized water as additive, and internal layer consisted of various finger-like holes. The forming mechanism of microstructures was investigated according to the effects of Tween80 molecular chain structure on the viscosity and surface tension of casting solution. Significantly, the modified membranes obviously exhibited higher pure water flux, which was increased by 257 % compared with the pristine membrane. The rejection to ink suspension was over 99 %. Furthermore, the antifouling performance of modified membrane was also greatly improved on account of the above microstructure and more hydrophilic surface. This study provides a new idea for the construction of membrane microstructure and the hydrophilic modification.

By structurally and practically analyzing the use of Nd: YAG laser for cutting black walnut veneer, this study considered practical and environmental concerns regarding the global warming protection measures. A numerical model of laser wood veneer cutting was based on the relation between process parameters and the material thickness. A pulsed Nd: YAG was used to cut black walnut veneer of 0.3 mm thickness under different machining conditions regarding laser power and cutting speed to study the cut kerf width. An analysis of variance was conducted to test the significance of machining parameters. The parameters studied were laser power, cutting speed, kerf width, cut surface, safety, and eco-friendliness. The results showed that the kerf width decreased significantly with increased cut speed and, inversely, by laser output power. An efficient cut with a narrow kerf, clean and smooth, with less burn, was possible at laser cutting speeds of 2.5, 5.0, and 5.5 mm/s with kerf widths of 0.544, 0.69, 0.62 mm, respectively. As multiple factors affect the micro-thin wood laser cutting process, finding the optimal process parameters is crucial for successful machining with no burn effect.

By combining honeycomb core with the traditional crash box, an innovative foam-filled honeycomb core structure crash box is proposed to improve safety performances. Three kinds of honeycomb core crash boxes were obtained by filling the inside of the traditional crash box with the quasi-honeycomb core, the quasi-square honeycomb core and hexagonal honeycomb core. It is deduced that the energy absorption of the quasi-honeycomb core crash box increased by 42.2 %, the peak of the collision force reduced by 8.9 %. The hexagonal honeycomb core crash box and the quasi-square honeycomb core crash box also enhance the energy absorption characteristics, but the peak impact force increased by 5.6 % and 9.6 %. After filling of the Expanded Polypropylene (EPP) foam, the peak collision force of the EPP hexagonal honeycomb core crash box and the EPP quasi-square honeycomb core crash box increased by 10 %, while Fmax of the EPP quasi-honeycomb core crash box reduced by 2.3 % and the energy absorption increased by 54.6 %. Six structures were compared to highlight the energy absorption characteristics of the filling the inside of the traditional crash box with the light in weight honeycomb core and EPP foam. The research results provide a new idea for the design of crash box.

Hydrodynamic lubrication of rectangular micro-textures on sliding contact surfaces is investigated using numerical calculation methods. The theoretical models for the slider surface are developed and the film pressure is used to evaluate the hydrodynamic lubrication based on the Reynolds equation. Meanwhile, the geometry and distribution of the rectangular dimples are optimized for maximizing the average film pressure. Results show that the film pressure is dependent on the geometry and distribution of the rectangular micro-dimples. The optimal geometry of the single rectangular dimple is obtained, and the spacing has an important influence on the film pressure. The distribution types of rectangular dimples affect the hydrodynamic lubrication significantly and the interlaced array of the rectangular micro-dimples is beneficial to enhancing the hydrodynamic lubrication. Meanwhile, the rectangular dimples with 72° interlaced angle exhibits the best effectivity.

Ti−6Al−4V alloy was fabricated via selective laser melting (SLM) to improve its corrosion resistance for implant. The microstructure and electrochemical corrosion behavior were investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), electrochemical test and contact angle test. It can be found that the as-selective laser melted (as-SLMed) Ti−6Al−4V alloys show β columnar microstructure in building direction and nearly circular checkerboard microstructure in scanning direction, while the wrought and wrought+HT samples exhibit equiaxed microstructure. The as-SLMed Ti−6Al−4V alloy exhibits better corrosion resistance than the wrought and wrought+HT samples due to hydrophobicity, high grain boundary density and uniform distribution of alloying elements in simulated artificial saliva at 37 °C.

Smart materials based on photo-responsive dynamic covalent bonds have the potential for use in many applications, such as photo-modulated manipulators, actuators and self-healing materials. However, the development of high-performance multifunction visible-light-driven dynamic covalent systems has been insufficient. Herein, we report a novel linear polyurethane elastomer (HABI-PU) containing visible-light-switchable hexaarylbiimidazole (HABI) units in the polymer backbone with photo-induced scission and rapid healing capacities. When exposed to 405 nm light, the scratches on the HABI-PU film took only a few seconds to heal. More serious cut damage could be healed after exposure for 30 s and placed in the dark at room temperature for 6 h. Moreover, when a certain weight was loaded during light irradiation, the elastomers broke off as the toughness of the HABI-PU elastomers decreased. The reversible dissociation of the C–N bond of the HABI units caused the scission of long polymer chains into short chains upon light irradiation and further endowed HABI-PU with the properties of photo-induced fracture/healing. Such elastomers are promising for application in the fields of photo-controlled triggers, biomimetic systems, recycled materials, optical machining, and other engineering streams.

Homogeneous NaBH4-reduced Co3O4 thin film electrodes with enhanced oxygen evolution electrocatalysis was obtained via a controlled-synthesis route. Firstly CoOx colloids was synthesized via ethylene glycol solvothermal method and cast on conductive glass substrates. The oxygen evolution reaction (OER) electrocatalysis of these as-prepared Co3O4 thin films were then significantly enhanced via a simple surface reduction by NaBH4 solution. The OER catalytic performance of the NaBH4-reduced thin films were strongly dependent on the NaBH4 concentration. The use of NaBH4-reduced thin film electrodes for OER in alkaline solution supported higher current density and consequently a negative shifts of the onset potential compared to that of the pristine. The optimal B12.5, 20-Co3O4 thin films exhibited excellent OER catalytic performances: At the current density of 10 mA·cm-2, a low overpotential of 365 mV and a small Tafel slope of 59.0 mV·dec-1 were observed. In addition, these B12.5, 20-Co3O4 thin film electrodes possessed good stability that can well recover its OER performance in a 24-h chronoamperometric stability test.

Aluminum anodization process requires a lot of electrical energy for the migration of ions in a barrier-type oxide film, in which electrode polarization leads to massive energy consumption. The cathodes are considered to be modified with catalysts, reducing their hydrogen evolution reaction (HER) overpotential in order to improve its energy utilization efficiency. In this study, N-doped carbon nanotube (NCNT)-supported Pt nanoparticle (NCNTs/Pt) electrodes were prepared instead of the traditional stainless steel cathodes. Considering the neutral electrolyte used for the aluminum anodizing process, the NCNTs/Pt electrodes were tested in an ammonium adipate (pH = 6.8), exhibiting an overpotential of 125 mV at −10 mA cm−2 and a mass activity of 107.6 A gPt−1. The NCNTs/Pt electrodes were employed as cathodes to measure the aluminum anodization energy consumption, which enabled 9.04% reduction at a formation voltage of 150 V compared with stainless steel electrodes. This study provides a way for energy conservation in the aluminum anodization process, with the novel pathway altering the cathodic electrode using carbon-based noble metals as efficient catalysts.

As a type of cellular materials, honeycomb structures exhibit great advantages in mechanical properties and crashworthiness. This paper proposed a new kind of combined quasi-honeycomb core and stud...

Biological tissues are capable of stiffening and self-healing as they are strained or damaged in order to preserve their integrity and functionalities. However, mimicking both strain-stiffening and...

Silicon oxycarbide (SiOC) as a prospective electrode material for next-generation lithium ion batteries (LIBs) was restricted by the unsatisfactory discharge capacity and inflexibility used in flexible and wearable electronics. Herein, freestanding flexible SiOC/nitrogen-doped carbon fiber films are constructed through electrospinning process followed by carbonizing in NH3 atmosphere. In this way, SiOC particles are tightly embedded in N-doped carbon fibers, forming a 3D conductive network to promote electron transport and faster reaction kinetics. The nitrogen dopants create more defects in carbon fibers matrix, which improve the electronic conductivity and electrochemical active sites of the electrodes. Owing to the above synergistic effect, SiOC/nitrogen-doped carbon fiber electrodes exhibit a high initial Coulombic efficiency of 73 % and a reversible remaining capacity of 595 mA h g−1 at 200 mA g−1 even after 200 cycles. The electrodes with good flexibility can successfully drive a light-emitting diode even when the package battery is bended to 180°.

Thermionic electron sources are scaled down to the microscale on a chip and batch fabricated on 4-in silicon wafers by utilizing microfabrication technologies and exploiting carbon nanotubes as microscopic filaments of thermionic electron emission. The microfabricated on-chip thermionic electron sources not only satisfy the metrics of compactness and ease of batch fabrication, but also exhibit the advantages of good performance reproducibility (±6.9% variation over 100 test cycles under a driven voltage of 3.5 V) and high emission stability (fluctuation < 5% for emission current level of ≈10−8 A over 900 s) under a relatively low vacuum condition (10−4–10−2 Pa). Furthermore, to extract electrons and tune emission current, an extraction gate with a mesh is monolithically integrated with the thermionic electron sources using anodic bonding technique. The integrated electron sources exhibit a strong gate controllability and a considerable electron transmission ratio of ≈76% through the extraction gate. All these results make our devices a promising type of on-chip electron source in the applications of miniature vacuum electronic devices/systems.

Hierarchical porous zinc oxide (ZnO)/silver (Ag) microspheres were prepared by two-step method. The porous ZnO microspheres were prepared firstly, and then Ag nanoparticles were evenly anchored on the surface of ZnO microspheres by Sn2+ activation method. The results show that ZnO is wurtzite phase, and Ag particles are only coated on the surface of ZnO microspheres. Compared with pure ZnO, there are two obvious absorption peaks of Ag-doped ZnO, which corresponds to the ultraviolet absorption peak of ZnO and the plasma resonance absorption peak of Ag, respectively. The intensities of photoluminescence peak of ZnO/Ag microspheres are significantly lower than that of pure ZnO. Moreover, ZnO/Ag microspheres show higher photocatalytic activity than ZnO, which may be attributed to the existence of highly dispersed Ag.

Cathode plate affects the quality and cost of gold refining. Ag-Ti bimetal cathode materials were fabricated by vacuum hot-press diffusion bonding in this paper. Microstructure morphology and an analysis of the bimetal show that metallurgical interface has been successfully constructed between the Ag and Ti. The interfacial layer consisted of the intermetallic compound AgTi and the solid solution α-Ti. The hardness at the interface reaches a maximum of 467 HV at a bonding temperature of 890 °C. The bath voltage of the Ag-Ti cathode plate is only 2/3 of that of the Ti cathode plate when the thickness ratio of Ag and Ti is 8:1. The gold yield is increased by 10 %, approaching 80 %.

Starting from ZrO2 and boron (molar ratio: 1:4), four ZrB2 powders were synthesized by borothermal reduction method, three of which were designed to introduce minor modifications by combining solid solution with Ti and/or water-washing. The sinterability, microstructures, mechanical properties and thermal conductivity were investigated. In comparison with the conventional borothermal reduction, the modified methods offered significant improvement in terms of densification of ZrB2 ceramics, particularly the mixture that included water-washing. Owing to the refined particle size and boron residues, ZrB2 ceramics from the modified borothermal reduction which included water-washing demonstrated nearly full densification, Vickers hardness of 14.0 GPa and thermal conductivity of 82.5 W/m K after spark plasma sintering at 2000 °C for 10 min. It was revealed that the properties of ZrB2 ceramics could be enhanced utilizing the proposed minor modification, starting from the same raw materials and adopting the same sintering conditions.

A series of silica nanoparticles (SNP-1, SNP-2, SNP-3, SNP-4, SNP-5 and SNP-6) were synthesized in ethanol by the hydrolysis and polycondensation reaction of tetraethoxysilane with the aids of water initiator and ammonia catalyst and then investigated in a comprehensive manner in terms of morphological structure by using synchrotron transmission small-angle X-ray scattering and grazing incidence wide-angle X-ray scattering and combined together with dynamic light scattering, scanning electron microscopy, infrared spectroscopy and thermogravimetry. They were confirmed to be successfully synthesized as oblate amorphous ellipsoids (Re = 9.70∼56.30 nm, equatorial radius; e = 0.78∼0.80, ellipsoidicity) with sharp surfaces in single unimodal and narrow size distributions. The radial density profile details, including two-phases (i.e., less dense core and denser shell), were determined for the first time, in addition to a set of structural parameter details (radius of gyration, radius, core radius, shell thickness, and radius distribution). Larger particle was synthesized conveniently by higher loading of ammonia solution with respect to the silane monomer. The as-synthesized silica particles were found to undergo two-step mass loss behaviors in heat treatment up to 500 °C; the first-step loss took place below 120 °C due to removals of physically absorbed water molecules and possible solvent residues and the second-step loss above 180 °C occurred by removals of water and ethanol byproducts due to the post condensation reactions of hydroxy and ethoxy residues.

The morphology of a polymer brush is of great importance in determining surface properties, such as lubrication. In light of this, we systematically study the morphologies of ring polyelectrolyte b...

A series of spinel CuM2O4 (M = Mn, Fe, and Al) was used as the catalyst to investigate the effective degradation of toluene, and then CuMn2O4 with better catalytic activity was selected as the research object to study its activity at different ratios of Cu and Mn. Meanwhile, CeO2 was introduced to modify CuMn bimetallic oxide to improve its catalytic performance. The structure, morphology, and valence states of surface elements of as-prepared catalysts were characterized by XRD, TEM, SEM, N2 adsorption-desorption, XPS, and H2-TPR. Using toluene as a probe molecule, the catalytic activity of the catalyst was tested and the results showed that the conversion rate of toluene catalyzed by CeO2-CuMn2O4 catalyst can reach 90% at 200 °C (T90) and 100% at 240 °C (T100). The CO2 yield can also reach 100% at 248 °C. Moreover, the possible catalytic mechanism for toluene by the CeO2-CuMn2O4 was briefly explored. The catalytic oxidation of toluene over the oxide follows the Mars-van Krevelen mechanism.

Silicon carbide ceramics were pressureless joined by using Ti foil and Si powder, which generated Ti3SiC2 phase as the interlayer. The phase composition, microstructure and the shear strength were investigated. It was revealed that the SiC assembly after joining at 1500oC showed the high shear strength of 76.2 ± 19.5 MPa. The secondary phase of TiC within the interlayer was expected to contribute to densification improvement of Ti3SiC2 phase and thermal stress reduction.

This study investigated the influence of the geometry of the draft tube on the mass transfer and energy efficiency in the airlift reactor with helical sieve plate (ALR-HSP). The power consumption efficiency was 46%–53% higher than the control condition by optimizing the draft tube. A set of empirical equations was used to describe the gas holdup and volumetric mass transfer coefficients corresponding to the geometry of draft tubes in the ALR-HSP for the water–air system. The comparative cultivation of Pichia pastoris was carried out using the ALR-HSP and the conventional airlift reactor (CALR). The biomass increased by 20%, the maximal specific growth rate during the logarithmic growth phase nearly doubled, and volumetric oxygen transfer coefficient increased by 21%–47% under the same culture conditions. Results preliminarily demonstrated the superior performance and practicability of the ALR-HSP in enhancing oxygen transfer efficiency and aerobic biological reaction efficiency.

Electronic devices with configurability to providing multiple functions are of great interests for their superior adaptability to the ever-changing and multifarious application scenarios. Here, we report flexible integrated circuits (ICs) possessing configurable functions constructed with dual-material gate (DMG) devices based on carbon nanotube thin films, which can serve as either transistors or diodes, on a 2-μm-thick parylene substrate. When configured as a transistor, the DMG device has great advantages over the normal-gated (NG) devices regarding the current on/off ratio (Ion/Ioff), the subthreshold swing (SS) and the drain-induced barrier lowering (DIBL) due to the regulated energy band distribution in channel area. When operating as a diode, a typical DMG device demonstrates a sufficient rectification ratio of 8 × 10 4 and a diode-on-current of over 26 μA. Scalable manufacturing of DMG devices was also demonstrated with great uniformity both in diode and transistor configurations. Finally, multifunctional integrated circuits, which can dynamically switch their function from rectifier to follower or from OR gate to voltage adder by changing controlling signals, were constructed. The functional-configurability, together with scalable manufacturing and the realization on ultrathin flexible substrates, will open up great opportunity for the future environmentally-adaptive system in the field of flexible electronics.

The Automated Fiber Placement (AFP) process shows great potential for efficient manufacturing of large composite structures. Although these technologies are widely used to produce large composite components, inconsistencies such as overlapping tapes or gaps between adjacent tapes may occur during the manufacturing. The combination of ply-drops with triangular gaps may cause a more severe strength knockdown. Within this study, modeling tools were firstly developed to automatically generate the ply-by-ply model with gaps and ply-drops based on the input ply books and dimensions for modelling the combination of ply-drops with triangular gaps. Then the comparison of the ply-drop + gap model with the specimens demonstrated that the cross-section views of the specimen can be well captured in the model and a good correlation was observed between model predictions. These tools have then been used to study and analyze the effect of ply-drop + gap in AFP manufactured tapered laminate composites, both the test and model results showed that the existence of triangular gaps at ply-drops reduced the strength further than the ply-drops only and the strength of ply-drop + gap model has a larger deviation from the test results than the ply-drop only model.

Energy-efficient membranes are urgently needed for water desalination and separation due to ever-increasing demand for fresh water. However, it is extremely challenging to increase membrane water flux and simultaneously achieve high rejection rates of cations or organic dyes. Herein, we report a tannic acid (TA) assisted exfoliation method to fabricate TA-modified MoS2 (TAMoS2) nanosheets with high production yield (90 ± 5%). The TAMoS2 nanosheets membranes show excellent non-swelling stability in water. It is found that a hybrid membrane with 1 wt% of TAMoS2 in MoS2 nanosheets demonstrates overall better performance than pure MoS2 and TAMoS2 membrane. Such a hybrid membrane with a thickness of 5 µm shows fast water flux at around 32 L m−2 h−1 (LMH) and >97% rejection of various cations under static diffusion mode. Under vacuum-driven filtration condition, the as-prepared hybrid membrane demonstrates ultrafast water flux of 15,000 ± 100 L/(m2 h bar) and 99.87 ± 0.1% rejection of multiple model organic dyes. To the best of our knowledge, the above performances are superior to those of all MoS2-based membranes reported previously in terms of water flux and ion/dye rejection. This work represents a leap forward towards the practical applications of 2D TAMoS2 membranes in various engineering and environmental areas.

We theoretically demonstrate a broadband mode converter and multiplexer based on plasmonic waveguides loaded with structured dielectrics. The proposed device can realize conversions between a fundamental TM0 mode and a first order TM1 mode, as well as (de)multiplex them with another TM0 mode. Our design exhibits as wide as 400 nm bandwidth and as short as 6~7 μm coupling length. This work has potential application in high density photonic integrated devices for both computing and communication applications.

Alumina as dielectric material is commonly prepared via anodizing high purity etched foils in electrolyte, which vitally determines the performance of aluminum electrolytic capacitor. However, the ...