- Ei，ESCI收录期刊
- 中国科学引文数据库(CSCD)核心期刊
- 中文核心期刊
- 文摘与引文数据库(Scopus)
- 剑桥科学文摘(CSA)
Metamaterials have drawn extensive attention for their fine regulation of electromagnetic waves at subwavelength scales. They have abundant electromagnetic modes, and support highly confined and enhanced electromagnetic fields on the surface which are highly sensitive to the surrounding dielectric environment, so they can be used in label-free optical biosensing. Compared with traditional optical biosensors, metamaterial biosensors have many advantages, such as miniaturization, integration, high sensitivity and multi-function customization. The recent progress of metamaterial biosensors in visible light and near infrared, middle infrared, and terahertz spectrums was summarized in this paper, including refractive index biosensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, and terahertz biosensing.
Chemical reactions based on the characteristics of silicon-oxygen bonds and different conditions are important methods to construct new organic/inorganic siloxane functional materials with very different structures and unique properties, which have aroused widespread attention in the academic community. The new silicon-oxygen functional materials have both organic/inorganic compound properties, and are widely used in many fields for their good biocompatibility, high and low temperature resistance, and electrical insulation properties. The research fields and development status of the design, synthesis and application of siloxane compounds were reviewed in this paper, focusing on the design and synthesis methods of linear structure (one-dimensional structure), nonlinear structure (two-dimensional structure), polyhedral oligomeric silsesquioxane compounds (three-dimensional structure) and organic/inorganic hybrid siloxane compounds, and the application progress of siloxane compounds in biomedicine, aerospace, functional materials and tertiary oil recovery will be promoted by studying stretchable polysiloxane elastomer, siloxane compound coating, new silicone functional materials for oil displacement and so on.
Graphite carbon nitride (g-C3N4) is a visible light responsive semiconductor material with the advantages of high stability, low cost, high adjustability of structure and property. With the continuous development of green and non-secondary pollution photocatalytic technology, g-C3N4has gradually become a research hotspot in the field of environment and energy science. Nevertheless, the bare g-C3N4 exhibits relatively low photocatalytic efficiency, which is due to the rapid recombination of photogenerated charge carriers and low visible light utilization efficiency. Among many modification methods, heterogeneous coupling is considered to be an effective method to improve the photocatalytic performance of g-C3N4. In recent years, with different inorganic semiconductors, precious metals, and carbon materials, heterogeneously coupled with g-C3N4, the researchers promoted the transfer efficiency of photoelectrons in the photocatalytic system, broadened the absorption range of visible light of g-C3N4-based photocatalysts, and enhanced the catalytic stability and structure regulation of g-C3N4. The catalytic mechanism of heterogeneous photocatalysts and construction of heterogeneous photocatalytic system based on g-C3N4 were summarized, the research progress of g-C3N4-based heterojunction in degradation of environmental pollutants was discussed. Finally, the prospect of designing excellent g-C3N4-based photocatalyst and their applications in photocatalytic degradation of dyes, organic pollutants and reduction of toxic heavy metals with excellent performance and its prospect in the field of environmental pollutant removal were prospected.
Amorphous alloy powder can be obtained by rapid cooling atomization of certain alloy droplets. Fe-based amorphous alloy powder has been favored because of its low production cost and wide application range. Moreover, the application of Fe-based amorphous alloy powder provides a new solution for the application of bulk Fe-based amorphous alloys.The research progress of Fe-based amorphous alloy powder was reviewed, and its research status was summarized in four aspects: coating preparation, magnetic materials, laser 3D printing, and wastewater treatment. The advantages of Fe-based amorphous alloy powder in various fields were analyzed, and the research directions of Fe-based amorphous alloy powder in the fields of preparing high-quality coatings, reuse of aging magnetic powders and additive manufacturing were pointed out. Moreover, the application prospects of Fe-based amorphous alloy powder as sensing, control and other functional devices were prospected.In addition, it also shows great application potential in the fields of small size, low dimentional materials such as thin films and flexible electronics.
Numerical simulation can establish corresponding models for temperature field, molten pool shape, residential stress, microstructure evolution in the metal SLM process effectively. Meanwhile this model can accurately predict the performance of forming parts, and provide scientific basis for process parameters optimization, consequently boost the metal SLM to industry application. In this paper, the latest research progress of numerical simulation in the process of metal laser additive manufacturing was summarized, including temperature field, molten pool dynamics, residual stress and deformation in the forming part, and microstructure change.The latest progress of numerical simulation in metal SLM process was summarized, and the metal SLM process was analyzed. Finally, the future development trend was put forward that metal SLM process numerical simulation should be combined with big data, artificial intelligence, deep learning and other technologies and numerical simulation accuracy will be further improved, the processing window of metal laser additive manufacturing will be broadened, and guidance will be provided for the development of individual products.
In order to study the influence mechanisms of microstructure stability of high generation single crystal superalloys, the D1 and D2 alloys which contain 6%(mass fraction) Ru and 4.5%Ru respectively were prepared after complete heat treatment and long-term aging at 980 ℃ for 1000 h. The microstructure and alloying element distribution at different scales were examined and the results were analyzed combining with thermodynamic calculation. The results show that there are still high content of refractory elements segregating in the dendrite region after complete heat treatment, inducing to TCP precipitation in the dendrite after long-term aging. Ru and Re are the main forming elements of TCP in both D1 and D2 alloys, and more TCP phase precipitates in D1 alloy which contains more Ru than in D2 alloy. Because both Ru and Re can increase the d-orbital energy level of single crystal superalloy, higher Ru and Re content leads to more TCP phase precipitation. However, since Ru can reduce the segregation degree of Re in γ phase, the increase of Ru content can reduce the adverse effect of Re on the microstructure stability of single crystal superalloy. In this study, Ru plays a more significant role in promoting TCP phase precipitation, leading to more TCP phase precipitating in D1 alloy than in D2 alloy after long-term aging at 980 ℃ for 1000 h.
The hardness, conductivity and room temperature tensile test were used to study the properties of the new aluminum alloy aged at 110-140 ℃ for different time.The microstructure of the alloy was observed by transmission microscope (TEM).The results show that the optimum aging process of the new aluminum alloy is aging at 110 ℃ for 24 h.Tensile strength, yield strength and elongation are 808, 785 MPa, 6.9%, respectively.Aging temperature is the main factor affecting the type, density and size of precipitates.When aged at 110 ℃, the main precipitations are GPⅠ zones, GPⅡ zones and metastable η' phase. After aging at 110 ℃ for a long time (up to 96 h), GPⅠ zones and GPⅡ zones still exist stably.Compared with aging at 110 ℃, the precipitation process accelerates at 140 ℃.After aging at 140 ℃ for 4 h, no GP zone is observed, and the main precipitate phase is η'.After aging at 140 ℃ for 24 h, the main precipitates are η' phase and η phase.
A novel semi-solid extrusion shear process was proposed based on the idea of "process coupling and shortening process", which can improve the comprehensive mechanical properties by grain refinement. The casting process and solidification process of AZ31 semi-solid forming process were simulated via Anycasting software. The appropriate extrusion parameters were selected by comparing the results of simulation and experiment. The results show that in the deformation zone, the nucleation of AZ31 is promoted by dendrite fragmentation and pressure, leading to the achievement of a fine and uniform structure. The presence of the liquid phase is beneficial to coordinating the deformation during extrusion, reducing the effect of slip and twining on the texture, and thus the extrusion texture is weakened. The maximum basal texture strength is only 5.3 when the shear angle is 180°. Shear angle can further refine grains and improve comprehensive mechanical properties.The best mechanical properties are obtained at the shear angle of 150° with yield strength of 222 MPa, tensile strength of 309 MPa and elongation of 8%.
An as-cast high purity coarse-grained aluminum was deformed by dynamic equal channel angular pressing (D-ECAP) at high strain rate for one pass at room temperature.The twins formed during extrusion were studied with electron backscatter diffraction.The results show that deformation twins and annealing twins can be synthesized simultaneously in the coarse-grained aluminum via D-ECAP, which can be differentiated by their morphology, Kernel average misorientation (KAM) and the misorientation between adjacent grains.Due to the high strain rate and large shear deformation of D-ECAP, deformation twins with size of several hundred microns can be formed in aluminum with high stacking fault energy, and their shapes are lenticular.The twin boundaries deviate from ∑3 60°〈111〉 orientation relationship as a result of subsequent deformation, and the KAM values are mainly between 0.6°-1.8°.The high strain rate shear deformation contributes to the formation of abundant stacking fault, intricate dislocation patterns, and high deformation stored energy, and thus the ensuing temperature rise facilitates the formation of annealing twins.The morphology of annealing twins is irregular, but the orientation relationship of annealing twin boundaries is more close to ∑3 60°〈111〉 and the KAM values of annealing twins are mainly between 0.2°-0.5°.
In situ fast synchrotron computed tomography was used to investigate the semi-solid compression of nanoparticle-reinforced Al-10%(mass fraction) Cu composites. The three-dimensional images were used to quantitatively analyze the evolution of microstructure especially the micropores during semi-solid deformation process. The results show that the evolution of voids in nanoparticle-reinforced aluminum matrix composites during semi-solid compression has three main stages, namely the micropore closure stage, incubation stage and rapid growth stage. With the analysis of quantitative data and microstructure observation of void distribution in different deformation stages, semi-solid compressive deformation mechanism of aluminum matrix composites is further analyzed.The four-dimensional (three-dimension+time) study of Al-based composites under load using in situ synchrotron imaging technology provides a reference for exploring the semi-solid deformation behavior of aluminum matrix composites.
Based on thin plate tensile tests of super-elastic NiTi alloy at different temperatures, a trilinear elasto-plastic constitutive model was adopted and the effect of latent heat of phase transformation on the temperature rise was considered through an equivalent method of thermo-physical constants.The transformation pattern evolutions were simulated by finite element software ABAQUS, and the rate-dependent mechanisms were also revealed. The simulated results show that the stress-induced martensitic transformation occurs under tensile loading, which macroscopically exhibits as the initiation, propagation and merging of local transformation bands; due to the release of latent heat, the initiation of transformation bands is accompanied by local temperature rise, and peak temperature rise is closely related to the loading strain rate; the local transformation bands are at a certain angle to the loading direction, which is about 50°-65°; with the increase of loading rate, the sample is changed from the isothermal state to the adiabatic one, the transformation stress and local temperature rise increase then. Therefore, the transformation tends to occur in the low temperature region, which results in an increasing number of transformation bands. The simulated transformation patterns and temperature field evolutions of super-elastic NiTi alloy at different strain rates are in good agreement with the corresponding experimental results, which provide a reference for clarifying the evolution of transformation localization of the alloy.
In order to develop a new generation of high strength weathering steel for railway vehicle, V-N-Cr microalloyed Q690 weathering steel was produced by two-stage rolling, and the microstructures and mechanical properties were studied. The corrosion behavior of V-N-Cr microalloyed Q690 weathering steel and Q345 steel was studied by cyclic wet/dry corrosion tests. The results show that the microstructure of V-N-Cr microalloyed Q690 weathering steel is polygonal ferrite, acicular ferrite, lath bainite and a few M/A phase. The yield strength and tensile strength are 695 MPa and 815 MPa, respectively, with excellent impact performance. The crack propagation is effectively hindered by the interaction of grain boundaries with large and small angles. The surfaces of both kinds of steels have formed rust layer, and corrosion products mainly include α-FeOOH, β-FeOOH, γ-FeOOH and Fe3O4. After 360 h corrosion, the average corrosion rate of Q345 steel is 1.83 g/(h·cm2), and that of V-N-Cr weathering steel is 0.96 g/(h·cm2).
In low-temperature carbonization stage, stabilized polyacrylonitrile (PAN) fibers are pyrolyzed and recombined to transform into low-temperature carbonized fiber with rudiment of turbostratic graphite structure. The temperature regulation of low-temperature carbonization has an important influence on the structure and performance of the final carbon fibers. The reaction process of stabilized fiber during low-temperature carbonization stage, the effect of the regulation of low-temperature carbonization temperature gradient on the structural evolution of stabilized fiber and the structure and performance of carbon fiber were studied through 13C-NMR, Raman, XRD and mechanical property analysis. The results indicate that: in the process of low-temperature carbonization heat treatment of stabilized fiber, the carbon structure shows the degree of branched chain reaches a maximum of 0.99, after heat treatment at 450 ℃. When the heat treatment temperature reaches 550 ℃, the main reaction is the recombination crosslinking reaction of stabilized fiber's aromatic chain segments. The low-temperature carbonization temperature gradients affect the structural evolution of stabilized fibers. When the temperature gradient is 350-450-650 ℃, the 13C-NMR shift of the —C C group in the low carbon fiber treated at 450 ℃ is the largest, the branching crosslinking reactions in fiber are the most, causing the d002 of the low carbon fiber treated at 650 ℃ and the IA/IG of the corresponding high-temperature carbon fiber are the largest, the relative content of amorphous carbon is the largest and the mechanical properties of the final carbon fiber are the worst. However, when the temperature gradient is 350-550-650 ℃, the cracking and recombination crosslinking reaction in fiber are carried out in an orderly manner, resulting in the structure of low-temperature carbonized fiber and carbon fiber more perfect, and the density and mechanical properties of carbon fiber are improved.
The carbon fibers (CF) were surface modified by nitric acid treatment and polyamide 6 (PA6) solution sizing treatment, and a series of CF/PA6 composites with high strength and high modulus, low melting index, and excellent processability were prepared. Scanning electron microscope (SEM), differential scanning calorimeter (DSC) and melt index meter were used to test and characterize the microstructure, mechanical properties and crystallization behavior of the composite materials. The results show that a layer of PA6 film is formed on the surface CF after immersion and sizing treatment with PA6 solution, which greatly enhances the binding force between the fiber and PA6 matrix, and improves the dispersibility of CF. The overall strength and modulus of the composites are improved. The tensile strength of the CF/PA6 is increased by 80.8% and the elastic modulus is increased by 513.9% when the modified CF amount is 8% (mass fraction). The addition of modified CF can promote the transition of PA6 from the γ crystal form to a more stable α crystal form. At the same time, the crystallization temperature and crystallization rate of the composites are increased, so that the crystallization of the composites are more uniform, thereby reducing the melting index of the composite and improving its processing performance.
Polylactic acid (PLA) is a widely used biopolymer material. However, there are disadvantages such as poor toughness, poor hydrophilicity, and poor biological activity in the application process. It was modified with polyethylene glycol (PEG) and hydroxyapatite (HA).3D printing filaments of PLA/PEG/HA with different mass ratios were prepared by melt blending. And by analyzing the mechanical properties, crystallization properties, thermal properties, rheological properties of PLA/PEG/HA filaments, the more suitable filaments for fused deposition modeling of 3D printing (FDM) were screened, and then the high precision mechanical samples and bioporous scaffolds with good biocompatibility, cell value-added and differentiation were 3D printed. The results show that the addition of PEG improves the toughness of PLA and lowers the melting point of PLA. The addition of HA increases the elastic modulus and cold crystallization temperature of PLA/PEG/HA composites, and HA can also improve the flowability of PLA/PEG/HA composites. SEM and fluorescent labeling results show that the porous scaffold has good biocompatibility. The successful cultivation of bioscaffolds in vitro cells provides potential for further exploration of bioporous scaffolds in animals, biomedicine, and customized applications.
Potassium diformate (KDF) is a novel substitute for antibiotics, which is not widely used in livestock production. The P-type molecular sieve (Zeolite P) was prepared by hydrothermal method with loading KDF and dispersed in the carboxymethyl cellulose (CMC) solution. The dispersed CMC mixed solution was added dropwise to the FeCl3 solution for cross-linking. Chitosan-carboxymethyl cellulose-Zeolite P-potassium diformate pH-sensitive hydrogel antibacterial microspheres were prepared by coacervation method. FT-IR, TGA and SEM results show that CS and CMC form the structurally stable polyelectrolyte complex through ionic bonds, and Zeolite P is included in the CMC matrix. The difference in swelling study indicates that the hydrogel microspheres have high pH-sensitivity and can be applied for sustained-release under different pH value. The slow-release kinetics study shows that antimicrobial microspheres have a certain sustained-release effect on KDF. The first-order kinetic model and the Higuchi model fits well with release data. In vitro antibacterial experiments, the antibacterial microspheres display significant antibacterial property against Escherichia coli and Staphylococcus aureus in the concentration of the antibacterial solution at 24 mg/mL and 48 mg/mL. Antibacterial microspheres can effectively inhibit the growth of bacteria, and the antimicrobial microsphere model provides a theoretical basis for the use of KDF.
Two different morphological ZnO materials with hierarchical micro/nano structures were fabricated through solvothermal method and oxalate method, respectively. Their photocatalytic performances were evaluated by using the degradation of methylene blue (MB) solution as model reaction. The results show that the product via solvothermal method exhibits flower-like micro-spherical appearance assembled by many nano-flakes, while its counterpart derived from oxalate strategy shows micro-rod like morphology constructed by many nanoparticles. ZnO fabricated by oxalate method has much better photocatalytic activity towards MB degradation, whose reaction rate constant is 7.65 times as high as that one obtained by solvothermal method. The identification results for active radicals verify that ·OH and ·O2- are both formed in the two samples when they are irradiated under ultraviolet light. However, due to their diverse band structures, there is difference in number of active radicals produced in the reaction system, which can further lead to different photocatalytic efficiency for MB degradation. As for oxalate-derived ZnO, greater number of ·OH and ·O2- can be formed under the irradiation of ultraviolet light. Meanwhile, ·OH with strong oxidation capacity plays a dominant role in the photocatalytic reaction system. As a result, it possesses more excellent property in degradation of MB than that of ZnO originated from solvothermal method.
For advanced all-solid-state lithium batteries, the solid electrolyte is one of the most critical factors that significantly affect the performance of batteries. The Li7P2S8I solid-state electrolyte was successfully prepared by wet-chemical synthesis and subsequent vacuum heat-treatment method, taking P2S5, Li2S and LiI as the raw materials and tetrahydrofuran as the reaction solvent. The morphology, elements distribution, and phase composition of the electrolyte sample were studied by means of simultaneous thermal analysis, powder X-ray diffraction, Raman spectroscopy, scanning electron microscope, and energy dispersive spectrometer. The electrochemical properties of Li7P2S8I solid electrolyte were analyzed by AC impedance measurements, cyclic voltammetry, and DC polarization test. The results show that the optimal heat-treatment temperature of Li7P2S8I solid electrolyte is 230 ℃ and the obtained sample has nanoporous structure and each kind of elements is uniformly distributed in it. Electrochemical tests show that the ionic conductivity of the electrolyte at 25 ℃ is 1.63×10-4 S·cm-1, the activation energy is 0.388 eV, the electrochemical window reaches 5 V and the lithium ion transport number is larger than 0.999. In addition, the symmetrical cell assembled with the electrolyte and lithium metal can be charged and discharged stably for more than 262 cycles (525 h). This proves that the Li7P2S8I solid electrolyte prepared by this method has excellent electrochemical stability and chemical compatibility with the metal lithium anode.
YBa2Cu3O7-δ(YBCO) bulk material prepared by high temperature solid state reaction was milled and dispersed through ultrasonic process in ethanol to prepare nanoscale YBCO/ethanol sol. Then it was mixed with aniline or O-phenylenediamine and the organic/YBCO hybrid materials were obtained after concentration and being dried in vacuum. The influence of the organic on YBCO's chemical composition, phase, elemental valence and magnetic properties was studied by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and vibrating sample magnetometer(VSM). The results show that the infrared absorption of YBCO is not affected by the aniline or O-phenylenediamine within 0.05%-5%(mass fraction, the same below), however the intensity of the XRD peaks is significantly increased. The interaction between the N atom in aniline or O-phenylenediamine and the Y atom in YBCO is stronger compared with N-Ba or N-Cu. The superconducting transition temperature Tc and magnetization M of YBCO are significantly affected by the content of N element in the hybrid materials. When the content of N element exceeds 1%, Tc is significantly decreased and Mmin is increased accordingly.
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