- 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)
Electromagnetic interference problems have become an increasing issue with the rapid development of wireless information technologies, which has attracted global attention. The key solution to this challenge is to develop materials that can absorb electromagnetic waves. The ideal absorbing material should be a structural material integrating load bearing, heat protection and strong absorption. The carbon-based, ceramic-based composites and their electromagnetic absorption properties in recent years were summarized in this review. The ultimate goal of these absorbers is to achieve broader effective absorption frequency bandwidth at a thin coating thickness. The synthesis methods, structures and electromagnetic wave loss mechanism of several typical and well-received composites were introduced. The superiorities, research status and main problems of absorbing materials were described. Based on these progresses, the potential development direction of absorbing materials in the future was predicted.
With the rapid development of electronic equipment and wireless communication in recent years, problems of electromagnetic interference are also becoming more and more serious. It is urgent to develop high performance electromagnetic interference(EMI) shielding materials to alleviate the damage of electromagnetic interference. MXene(Ti3C2Tx) is a novel kind of 2D material with ultrahigh electrical conductivity and unique chemically active surface, and therefore exhibits extremely excellent electromagnetic shielding performance. The preparation, structural feature and EMI shielding mechanism of Ti3C2Tx were focused and introduced in this paper, the latest research progress on EMI shielding applications of Ti3C2Tx-based films and 3D porous materials was objectively reviewed and evaluated, and the main problem at the present was analyzed. In addition, the future development direction and tendency of Ti3C2Tx-based EMI shielding materials from the aspects of preparation, microstructure control and structure design and so on were also prospected in this poper, based on current development needs including developing low-cost, green and efficient Ti3C2Tx preparation methods, solving the long-standing oxidation problem of Ti3C2Tx, designing new structure of Ti3C2Tx-based EMI shielding materials and finding out other MXenes EMI shielding materials other than Ti3C2Tx, which can provide new ideas and guidance for the further development of the next generation of high-performance EMI shielding materials.
The CoSiB/Pt multilayers with Pt buffer layer were successfully manufactured by magnetron sputtering technique on the Si substrate with 300 nm of SiO2. The optimal period of the CoSiB/Pt bilayer was 2. The thickness of CoSiB/Pt bilayer and Pt buffer layer were modulated. The perpendicular magnetic anisotropy (PMA) of each of the samples and thermal stability were studied by anomalous Hall effect (AHE) method. The best structure was Pt(1)/[CoSiB(0.5)/Pt(1)]2. The optimal thicknesses of Pt buffer layer and CoSiB/Pt bilayer in the periodic multilayer were 1, 0.5 nm and 1 nm, respectively. The XRD analysis, hysteresis loop measurement and a series of annealing treatment of the best sample were conducted. The results show that the sample has obvious (111)CoPt diffraction peak, forms a good (111) texture, enhanced interface coupling and good crystallinity. The effective magnetic anisotropy constant Keff of the sample is calculated to reach 5.11×104 J·m-3; when the annealing temperature is 200 ℃, the intensity of (111)CoPt diffraction peak of the sample is significantly enhanced, a strong (111) texture is formed at the interface, and the Keff reaches a maximum value of 1.0×105 J·m-3. When the annealing temperature is no more than 400 ℃, the sample can still maintain good PMA. Multilayer film sample structure Pt(1)/[CoSiB(0.5)/Pt(1)]2 has good PMA and thermal stability, and the suitable annealing temperature is conducive to improving the sample's PMA.
Compared with traditional lithium-ion batteries, all-solid-state lithium-metal batteries (ASS LMBs) have attracted much attention due to their high safety and high energy density. However, the solid-solid contact of electrodes with solid electrolyte brings large interfacial impedance. Besides, the active lithium metal reacts with most solid electrolytes, leading to unstable interface. So interfacial problem has been one of the key issues to limit the development of ASS LMBs. Solid composite electrolytes with the advantages of inorganic solid electrolytes and organic solid electrolytes, have higher ionic conductivity and certain mechanical strength, showing excellent promising in the light of practical application. The research progress on interface amelioration of solid composite electrolyte and lithium anode was summalized in this review. The main strategy includes constructing a "soft contact" at the interface, adjusting the mechanical performance of the solid electrolyte and tuning the deposition dynamics of lithium ions. Furthermore, the perspectives on interfacial modification were presented.
Silicon has been a pivotal material for the next generation lithium-ion batteries, owing to its superior theoretical capacity (4200 mAh·g-1). However, the huge volume change of silicon during the process of lithiation/delithiation will lead to the instability of silicon-based anode. As a main composition of electrode, the binder plays a critical role in connecting the electrode components together and maintaining the stability of electrode, the use of an appropriate binder is essential to improve the cycling stability of silicon-based anode. Water-soluble binders which have abundant functional groups have received extensive attention due to their excellent performance in improving the electrochemical performance of silicon-based anodes. In this paper, the research progress of water-soluble binders used in silicon-based anode was reviewed. First, the properties of one-dimensional linear binders were summarized. On this basis, the research progress of composite binders with three-dimensional (3D) network structure was mainly introduced. The structure and properties of different 3D network binders were systematically analyzed. Finally, the preferred structure and properties of the water-soluble binders for silicon-based anode were proposed, and a train of thought for water-soluble binders' choice and design was provided.
Functional polymer material is a type of polymer materials with special functions such as catalysis, conductivity, photosensitivity, and biological activity. They have the function of transmitting, converting, or storing substances, energy, and information. Functional polymer materials have the characteristics of light weight, numerous varieties and strong specialty, which make them widely used in machinery, information technology, biomedicine and other fields. The development of functional polymer materials is very rapid. In order to meet the needs of new technologies in various fields, functional polymer materials are gradually developing towards multi-function such as electromagnetic materials and photothermal materials. With the emergence of smart polymers, functional polymer materials are gradually being developed towards intelligence, such as self-healing functional polymer materials and shape memory materials. The research progress of functional polymer materials in recent years was summarized in this article and their applications were briefly described, with emphasis on reactive functional polymer materials, optical functional polymer materials, electrical functional polymer materials, biomedical functional polymer materials, environmentally degradable polymer materials, shape memory polymer materials and smart polymer hydrogel. At present, most functional polymer materials only have traditional functions such as photoelectricity or special functions such as shape memory. It is believed that functional polymer materials with both traditional and special functions will be the development direction of future materials.
3D printing as an important, fast-growing manufacturing technology is triggering major innovations in many fields, such as medicine, aerospace, automobile and food. The main advantages of 3D printing include design freedom, mass customization, waste minimization, and rapid prototyping, etc. The personalized features enable 3D printing to prepare products based on the patient's condition to help the patient recover. With the increasing demand for precision and personalized medicine, 3D printing is gradually being applied to implant manufacturing, diagnostic platforms and drug delivery systems. Therefore, this article outlines the development of 3D printing technology, which introduces medical materials that can be used for 3D printing, and the application of 3D printing technology in the medical field. Finally, the challenges and development prospects of 3D printing technology in the medical field are summarized and discussed.
The thermodynamic and kinetic basic theories of high temperature oxidation of metals and the theoretical conditions for the formation of protective oxide scale on FeCr alloys were described briefly. The characteristics of oxide scale structure and oxidation kinetics of traditional martensitic steel were summarized. Three new characteristics of oxidation behavior of new martensitic steel were summarized, namely good oxidation resistance, anomalous relationship between temperature and oxidation rate, and a special Cr-rich layer.It was pointed out that the oxidation behavior of some new martensitic steels is close to that of austenitic steels, and the oxidation resistance of martensitic steels was expected to be increased to the level of austenitic steels. The effect of Co, W and Si on the internal/external oxidation transition is the key research direction in the future.
The preparation of 7××× series aluminum alloy by selective laser melting technology (SLM) is hindered by hot tearing. Novel ZrH2 modified 7075 composite powders were prepared by the low-energy ball milling technology. Zirconium-containing 7××× series aluminum alloy was then prepared by the SLM process. The microstructure and mechanical properties of the samples with different ZrH2contents (0.5%, 1.0%, 1.5%, mass fraction, the same below) were systematically investigated. The results show that the addition of ZrH2 can significantly reduce hot tearing and change the microstructure. When 1.5% ZrH2 is added, the hot tearing is completely eliminated and the grain microstructure is entirely composed of fine equiaxed grains. The transition of columnar grains to equiaxed grains is attributed to the in-situ formation of L12-Al3Zr which provides numerous nucleation positions for solidification. After T6 heat treatment, the tensile strength, yield strength and elongation of SLMed sample are (550±10), (490±5) MPa and (12±1)%, respectively. Fractography analysis shows a large number of dimples on the fracture surface after tensile testing, indicating ductile fracture mode.
DD6 single crystal superalloy specimens were prepared by spiral crystal selection method. After standard heat treatment the long term aging at 980 ℃ was performed for 2000 h. The influences of the microstructural evolution and mechanical properties of DD6 single crystal superalloy after long term aging at 980 ℃ were studied. The results show that with the prolongation of long term aging time, the size of γ' phase in the alloy increases. After long term aging for 2000 h, the size of γ' phase is about 1 μm, and there is no TCP phase precipitation, which shows that DD6 alloy has good microstructural stability. The stress rupture life of sample after long term aging for 2000 h is 180.16 h at 980 ℃/243 MPa, which is 56.3% of heat treated state, and 144.42 h at 1070 ℃/130 MPa, which is 35.31% of heat treated state. The fracture mode is microvoid coalescence fracture. The tensile strength and yield strength of the alloy after long term aging for 2000 h are reduced by 5.55% and 5.88% at 760 ℃, and 11% and 10.59% at 980 ℃, respectively.
The effect of Li content on the ageing precipitation behavior of Al-3.0Mg-0.6Si alloy was investigated by transmission electron microscopy. The evolution and distribution of the precipitation phases in alloys with different Li contents during the artificial ageing at 170 ℃ were analyzed. The results show that the addition of Li changes the ageing precipitation behavior of Al-3.0Mg-0.6Si alloy.In the alloy with 2.15%(mass fraction) Li addition, the spherical δ'-Al3Li phases are formed first in grain interiors, while the needle-shaped β″-Mg2Si phases gradually precipitate at the later ageing stage. After ageing for 192 h, there are obviously dual phase precipitation of spherical δ' phase and needle-shaped β″ phase formed.However, β″ phase precipitation is not found in the alloy with 3.12%Li addition during the observed ageing stage. In addition, there are no precipitation phases at the grain boundaries of the Li-containing alloys, and the precipitate-free zones (δ'-PFZs) and δ' phase are found nearby the grain boundaries. After ageing for 100 h, the alloy with 2.15%Li addition precipitates needle-shaped β″ phase in the δ'-PFZs regions. Both the half width size and growth rate of the δ'-PFZs in the alloy with 2.15%Li addition are greater than that of 2.68%, 3.12%Li alloys.
The hot corrosion behavior of the second generation nickel base single crystal superalloy DD421 coated with 90%(mass fraction) Na2SO4+10%NaCl (molten at 750 ℃) and pure Na2SO4 (solid state at 750 ℃) was investigated by salt coating method in 750 ℃ atmosphere (without SOx atmosphere). The results show that in the corrosion medium of molten mixed salt, the sulfidation reaction is mainly caused by the corrosion of liquid molten salt. After 100 h of hot corrosion, the main corrosion products are typical simple oxides (Al2O3, Cr2O3, TiO2) and Ni/Cr/Ti sulfides. However, in the pure Na2SO4 solid salt hot corrosion experiment, the corrosion products of the alloy after 100 h of hot corrosion are basically the same as those in the mixed salt test, but the thickness of the corrosion layer is relatively thinner and the size of sulfide is relatively larger. Combined with thermodynamics and microstructure analysis, it is clear that the alloy elements can react with solid Na2SO4 salt in the corrosion environment without SOx atmosphere.
TiMo/ZrVFe getter was prepared by powder metallurgy vacuum sintering method. The materials were analyzed by X-ray diffraction(XRD), particle size analyzer, dynamic flow method and vibration test. The influences of the ZrVFe alloy particle size, phases, proportion of composite material on sorption performance and strength were studied.The results show that the content of Fe element in ZrVFe material increases to generate more Laves (Zr(VxFe1-x)2) phase of C15 structure which can improve sorption performance, and the initial pumping speed of Zr-24%V-8%Fe(mass fraction) alloy reaches 1791 cm3·s-1·cm-2, which is 1.5 times as that (1206 cm3·s-1·cm-2) of the original Zr-24.6%V-5.4%Fe getter, the pumping speed decreases more slowly with the progress of the gettering process. The sorption performance and strength of the composite are affected greatly by adding different contents of Zr-24%V-8%Fe alloy, the sorption performance gradually improves with the increase of adding alloy. The initial pumping speed increases by 26.4% compared with that of TiMo material and an ideal pumping platform appears when 20%ZrVFe alloy is added.However, the strength of the composite decreases distinctly with the mass loss of 2.48% when the addition ratio is 30%.
Supercapacitors have become a new type of energy storage device widely used due to their high efficiency, fast speed and good cycle stability, and electrode material is a key issue restricting their development. The porous niobium nitride fibers were prepared by electrospinning combined with reduction nitride technology using pentachloride as raw material, and Nb4N5||Nb4N5 symmetrical button capacitance was prepared. In order to improve the electrochemical performance of electrode material, NaHCO3 was added into Na2SO4 electrolyte. The results show that the prepared niobium nitride fiber exhibits a tetragonal phase, continuous and porous on the surface. The porous niobium nitride electrode has two mechanisms of electric double layer and pseudocapacitive energy storage. The specific capacitance of the capacitor increases to 187 F·g-1 with the NaHCO3 addition of 15 mmol·dm-3. The buffering effect inhibits the dissolution of niobium nitride, effectively reduces the solution resistance, the solution impedance R1 and the diffusion impedance WR reduce to 1.22 Ω and 1.47 Ω respectively and the ionic conductivity improves. The carrier concentration increases to 6.58×1024 cm3, and the relaxation time of the capacitor is shortened to 0.24 s at the same time.
ZIF-8 attracted more attention as the carbon support for oxygen reduction reaction catalyst due to its large specific surface area and regular pore structure in recent years. A series of FeN/ZIF-8 catalysts were prepared using ZIF-8, 1, 10-phenanthroline as carbon and nitrogen precursor, as well as FeSO4·7H2O, FeAc, FeCl3·6H2O and FeC10H10 were used as different iron precursors, respectively. The influence of different iron precursors on the structure and oxygen reduction reaction(ORR) activities of FeN/ZIF-8 catalysts were investigated by X-ray diffraction, specific surface area and pore size distribution measurements, transmission electron microscope, thermogravimetric analysis, and linear sweep voltammetry. The results show that the catalyst prepared with FeSO4·7H2O as iron precursor has the initial potential of about 0.93 V, and the ORR is a four-electron process, which has better oxygen reduction catalytic activity. Moderate specific surface area and pore size distribution, good crystal structure and uniform particle dispersion, as well as the presence of Fe3C are the possible reasons of resulting in better ORR activity of FeN/ZIF-8 with FeSO4·7H2O as the iron precursor.
Na-β″-Al2O3 was prepared with nano-η-Al2O3 powder by a double zeta process, MgO as stabilizer. The compactness, microstructure and mechanical properties of the samples were studied by Archimedes, SEM and three-point bending method, and the β″-Al2O3 phase content and ionic conductivity of the samples were studied by XRD and EIS. The results show that double zeta process is beneficial to improve the uniformity of sample structure. Nano-η-Al2O3 is easier to synthesize Na-β″-Al2O3 solid electrolyte than high purity α-Al2O3, the addition of appropriate MgO can increase the content of the β″-Al2O3 phase and the compactness of the samples, reduce the grain boundary resistance of the sample and improve the ionic conductivity of the electrolyte. Excessive MgO doping results in the growth of pore size in the samples, which will increase the grain resistance and decrease the ionic conductivity. The ionic conductivity of the electrolyte material reaches 0.0396 S·cm-1 at 300 ℃ when the amount of MgO is 2% (mass fraction).
For selectively sensing Tryptophan(Trp), the fluorescent Tb3+@UiO-66-(COOH)2 was prepared through loading Tb3+ into UiO-66-(COOH)2 via post-synthesis method. Transmission electron microscope (TEM), X-ray powder diffractometer (XRD), specific surface area analyzer, and X-ray photoelectron spectroscope (XPS) were used to analysize the morphology, composition and pore characteristics of the porous materials. Meanwhile, ultraviolet-visible spectrophotometer (UV-Vis) and fluorescence spectrophotometer were used to study the fluorescence characteristics. The results show that the energy transfer from organic ligand to Tb3+ leads to a bright green fluorescence. Among the 13 amino acids, only Tryptophan has obvious fluorescence quenching effect. This is because there appears a large overlap between UV-Vis absorption spectrum of Trp and excitation spectrum of the MOF, which indicates a strong competition effect for UV light. The absorption to UV light of Tb3+@UiO-66-(COOH)2 is decreased by Trp, leading to the weak fluorescence. Further investigation indicates the material can sensitively sense Trp (LOD, 5.53 μmol/L) and owns excellent anti-interference ability from other co-existing amino acids. Thus, this work not only demonstrates Tb3+@UiO-66-(COOH)2 can serve as a selective and sensitive sensor for Trp, but also provides a guideline for designing novel sensors for amino acids in the future.
Photothermal-assisted activation of peroxymonosulfate (PMS) is an effective way to promote the advanced catalytic oxidation performance. However, leaching of metal ions is a drawback for currently used metal-based catalysts, which limits their applications for water treatment. Therefore, it is important to develop high-efficient non-metal catalysts for photothermal-assisted PMS activation. Carbon nitride(CN) loaded with FeOx nanoparticles (FeOx/CN) were synthesized by the gelation-pyrolysis method. The as-prepared FeOx/CN catalysts were used to eliminate Rhodamine B (RhB) using the Fenton-like reaction by photothermal-assisted PMS activation. The crystalline structures, morphologies and light adsorption properties of the obtained nanocomposites were analyzed by using X-ray diffractometer, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, N2 adsorption-desorption and UV-vis spectrophotometer. The results show that the removal rate of RhB by CN/FeOx/PMS system can reach 98.0% under the condition of near neutral (pH=6) and photothermal(40 ℃ water bath and λ>420 nm visible-light irradiation) synergistic auxiliary reaction for 30 min. The trapping experiments demonstrate that holes (h+) and hydroxyl radicals (OH·) are major active species during the PMS activation process.
A novel nanoflower/rod-like hierarchical SnO2 was prepared one step on FTO conductive glass which has SnO2 seed crystal under hydrothermal condition at 200 ℃ with SnCl4 and NaOH as raw materials. The morphology, crystal phase composition and gas-sensing performance of the product were tested by SEM, XRD, N2 adsorption-desorption and gas-sensing tester. The results indicate that the product is tetragonal phase, and "nano carpet" is formed by nanorod arrays which are perpendicular to the base in the hierarchical SnO2 and with spherical nanoflowers growing on it, and the nanorods and petals are all assembled by fuzzy fibers; its specific surface area is 109.8 m2·g-1 which is 13 times than that of the ordinary precipitated SnO2 powder. The product has high gas sensitivity which is 36.1 to 1000×10-6 acetone, 7.9 times of the ordinary precipitated SnO2 powder.
The magnetic functionalized graphene based 17β-estradiol molecularly imprinted composite membrane (GO@Fe3O4-MIP) was successfully prepared by reversible addition fragmentation chain transfer (RAFT) polymerization technique using GO@Fe3O4 as carrier and 17β-estradiol as template molecule. High resolution transmission electron microscopy (HRTEM) and atomic force microscope(AFM), vibrating sample magnetometer(VSM) were employed to characterize the as-prepared samples. The results show that the calculated magnetic property of GO@Fe3O4-MIP is 12.89 A·m2·kg-1 and the thickness is about 6.45 nm. The adsorption equilibrium time of GO@Fe3O4-MIP on 17β-estradiol is 30 min, the maximum adsorption capacity is 28.62 mg/g. These findings confirm that GO@Fe3O4-MIP has high adsorption efficiency and good adsorption selectivity for 17β-estradiol.
Epoxy-matrix composites reinforced by CCF800H, the domestic high strength intermediate modulus carbon fiber, were prepared. Thermoplastic resin was used as the toughening agent of the resin. Through regulating the content of toughening particle in the epoxy resin, effects of the content of toughening agent on the mode-Ⅱ interlaminar fracture toughness of the composite were investigated. The results show that the thermoplastic toughening particles gather at the interlayers of the composite with the filtering effect of the carbon fibers on those particles. The interlayers get thicker with the increasing of the toughening agent. The mode-Ⅱ interlaminar fracture toughness of the composite is increased under the concurrent actions of the toughness and thickness of the interlayer resin.
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