Mullite fiber reinforced silica aerogel thermal insulation material was prepared by using silica sol as precursor, adding acid-base catalyst, impregnating and compounding with mullite fiber felt, and then gel aging and supercritical drying. The effects of high temperature treatment on the microstructure, structure and static/dynamic mechanical properties of reinforced silica aerogel thermal insulation materials were studied by SEM, XRD, infrared spectroscopy and digital image correlation method. The results show that the density of the material was about 0.39 g/cm³, and the thermal conductivity at 1 000 ℃ was about 0.068 W/(m·K). The compressive strength and compressive modulus increase with the increase of temperature. At 1 000 ℃, the compressive strength of 10% deformation was about 0.4253 MPa, which was 43.3% higher than that at room temperature before high temperature treatment. The compressive strain-displacement field show that the compressive force decreases gradually in the process of material internal transmission. The tensile strength at room temperature is about 1.39 MPa, and the tensile strength at 1 000 ℃ was 102.2% higher than that before high temperature treatment. High temperature treatment helps to make the distribution of tensile strain field more uniform.

Nano-SiO₂ aerogel foamed cement has the advantages of good thermal insulation performance, low density, easy construction, etc., and has wide applicability as a building thermal insulation material. In this paper, we investigated the changes in the properties of Nano-SiO₂ aerogel foamed cement by changing the dosage of blowing agent, and studied the changes in the pore structure by combining with optical microscope. The results show that when the foaming agent content is 0.66%, the fluidity of Nano-SiO₂ aerogel foamed cement decreases to 132 mm, the thermal conductivity decreases to 0.121 W/(m·K), the dry density decreases to 515 kg/m³, the thermal conductivity and dry density decrease by 31.2% and 25.2%, respectively, and the water absorption increases gradually. At the same time, with the increase of foaming agent content, the proportion of large pores in Nano-SiO₂ aerogel foamed cement increases, and the mechanical properties gradually decrease.

Ag-G-La₂O₃-WS₂ (75:15:4:6) composites were prepared by vacuum hot press sintering method. The effects of different sliding speeds (2.5 m/s, 5 m/s, 7.5 m/s, 10 m/s) and different apparent contact pressures (1.25 N/cm², 2.5 N/cm², 3.75 N/cm², 5 N/cm²) on the electrical friction wear properties of Ag-G-La₂O₃-WS₂ composites were investigated at a current density of 5 A/cm². The results show that the friction coefficient of Ag-G-La₂O₃-WS₂ composites gradually decreases with the increase of sliding velocity, and the electrical wear rate and contact voltage drop gradually increase. The contact voltage drop gradually decreases with the increase of apparent contact pressure, and the friction coefficient and electrical wear rate both decrease firstly and then increase. Thermal field emission scanning electron microscopy, three-dimensional laser confocal scanning microscopy and white light interferometry were used to study the surface morphology after the electric friction wear experiments and analyze the tissue structure and to explore the electric friction wear mechanism.

Sodium acetate trihydrate (SAT) is a highly promising hydrated inorganic salt phase change material, and it is suitable for hot water and heating systems. However, its large supercooling degree and phase separation seriously affect its applications. In this study, a SAT-based composite phase change material was prepared with a supercooling degree of 0.6℃ and a phase change enthalpy of 205.02 J/g by the addition of sodium Tungstate (ST) as a nucleating agent, curdlan (CUR) as a thickening agent, and sodium polymethacrylate (Na-PMAA) as a crystal-habit modifier. Meanwhile, after 400 charge/discharge cycles, its enthalpy was decreased by only 0.4%, with excellent cycling stability demonstrated. Furthermore, by the incorporation of carbon nanotubes (CNTs) and the utilization of UV curing technology, a shape-stable thermal energy storage unit was prepared. Under a constant heating temperature of 65°C, no leakage was observed, and the thermal conductivity was 0.2288 W/(m·K). This provides an efficient encapsulation method for SAT applications.

With the rapid development of electronic communication equipment, electromagnetic pollution is becoming more and more serious. Microwave absorbing materials play an active role in reducing electromagnetic pollution. Because of its structural effect, the wave absorbing materials with three-dimensional large-cell foam structure have attracted much attention in the field of high efficiency wave absorbing, especially in extreme fields such as aerospace. In this study, the foam-like precursor BiFeO₃ (BFO) was prepared by solid phase method, and then the BFO/C composite was prepared by coating technology. The effects of different carbon filling amount on the morphology, dielectric loss and microwave absorption properties of the composite were systematically investigated. The experimental results show that the BFO/C composite has a regular spherical foam shape, and the spherical holes are gradually filled with the increase of carbon filling amount. The microwave absorption performance of foamed BFO/C composites firstly increased and then decreased with the increase of C filling amount, among which BFO/C6 showed the best microwave absorption performance. At the matching thickness of 1.90 mm, the minimum reflection loss could reach -54.73 dB, the effective absorption bandwidth was 3.08 GHz, and it had the characteristics of multi-band absorption. This study reveals the excellent properties of foamed BFO/C composites in microwave absorption, indicating their wide application potential in the field of electromagnetic pollution protection.

Aluminum-tungsten composites, as high-performance lightweight structural materials with good overall mechanics and excellent gamma-ray shielding properties, have received wide attention and applications in the nuclear industry, aerospace field, etc. This paper describes the preparation pathway of high-performance aluminum-tungsten composites, interfacial reaction, mechanical properties of influencing factors, shielding properties as well as aluminum-tungsten composites in the aerospace, electronic communications, nuclear field, etc., analyzes the shortcomings of aluminum-tungsten composites, and provides references for the preparation of high-performance aluminum-tungsten products.

Laser cladding technology, as an advanced material surface modification method, not only produces coatings with tight and uniform microstructure, but also achieves metallurgical grade strong bonding with substrates. At the same time, due to the high energy density during laser irradiation, the surface roughness is reduced, resulting in excellent physical and mechanical properties of the coatings. In addition, this technology can effectively improve the surface quality of coatings, such as corrosion resistance, wear resistance, etc. It significantly enhances the friction-reducing and abrasion-fighting properties of the material's surface, thereby broadening the application spectrum of the matrix materials. The selection of coating materials is a crucial aspect in determining the effectiveness of laser cladding for achieving optimal coating properties. In this paper, the common material systems of antifriction and antiwear laser cladding layer (self-melting alloy powder, ceramic powder, rare earth element) are introduced. The antifriction coating can be prepared on the substrate by laser cladding. The antifriction and antiwear properties of the coating can be improved by adding certain alloy composition and chemical composition to the alloy powder. But when the metal ceramic composite coating is prepared, besides adding carbide ceramic powder and oxide ceramic powder, the antifriction and antiwear properties of the material can also be improved by optimizing the technological parameters and the proportion of ceramic powder. In addition, a certain amount of rare earth elements can be added to the surface of the substrate to improve the coating defects and increase the antiwear properties. However, there is a limit for the amount of rare earth elements to be added, if the limit is exceeded, new coating defects will be induced. Finally, the significance of laser cladding coatings is further highlighted, particularly in the industrial sectors that have embraced this technology. The application spectrum extends to a wide array of applications across various industries including agricultural machinery, where their durability and resistance to wear are crucial. For example, aerospace, where coatings play a vital role in enhancing the structural integrity of aircraft components, and automobiles, where they contribute significantly to the safety and efficiency of vehicles. Based on the current body of research findings, the potential for laser cladding coatings in the future is meticulously discussed and synthesized, outlining promising directions for further exploration and development within these sectors.

Microwave deicing technology has the advantages of high ice removal efficiency, low damage to road pavement, green environmental protection, and has a good application prospect in deicing of road pavement. The microwave absorption efficiency of traditional cement concrete pavement is low, leading to the slow microwave deicing speed. Therefore, the researchers introduced wave absorbing materials into the field of microwave deicing of concrete to improve the microwave heating efficiency of concrete. Based on the research status at home and abroad, three kinds of application of wave absorbing materials in the field of microwave deicing of concrete are analyzed, admixture, absorbing aggregate and absorbing coating. On this basis, the application research status of carbon absorbing materials, iron absorbing materials and ceramic absorbing materials in the field of microwave deicing of concrete is reviewed, and their application prospects and limitations are analyzed. Finally, the development of wave absorbing materials in the field of microwave deicing of concrete is prospected.

This paper systematically studies bismuth ferrite-strontium titanate (BiFeO₃-SrTiO₃, BFO-STO) composites, covering the preparation, structure, properties and applications of the materials in multiple fields. By comparing and analyzing common preparation methods such as solid-phase reaction method and sol-gel method, the effects of different synthesis processes on the structure and properties of the materials are explored. The BFO-STO composite combines excellent dielectric, ferromagnetic, ferroelectric, energy storage and optical properties, which can be adjusted and controlled by different synthesis methods, component ratios, elemental doping and introduction of crystal defects. In the field of capacitors, the design of multilayer film structure and doping modification significantly improve the dielectric constant, energy storage and cycle stability of the material. In the photovoltaic field, BFO-STO composites show excellent photoelectric conversion performance, and its photovoltaic efficiency is expected to be further improved through doping, defect engineering and solid solution optimization. In energy storage systems, the energy density and efficiency of the material are improved by doping, structural adjustment and optimization of preparation process, making it a potential energy storage material. Finally, a brief outlook on the future research direction of BFO-STO is given.

Biomedicine is related to human health and medical level, and thus it has close relations with human society, environment and survival. Barium titanate (BaTiO₃) nanomaterials have excellent piezoelectric/ferroelectric properties, good biocompatibility and biodegradability, and show significant application potential in the biomedical field. The applications of BaTiO₃ nanomaterials in biomedicine involves interdisciplinary integration of materials science, biomedical science, chemistry and physics, and this emerging discipline is currently in its early stages of development. In this paper, we first review the research progress based on piezoelectric properties of BaTiO₃ nanomaterials in sterilization, tissue engineering and biosensing systems. Subsequently, the applications based on ferroelectric properties of BaTiO₃ nanomaterials in the biomedical field such as wound healing and bioimaging are discussed. Finally, the challenges and development prospects of BaTiO₃ nanomaterials in biomedical applications are summarized.

Using ordinary Portland cement P.O 42.5 and graphene oxide (GO) as raw materials, recycled steel slag and coarse aggregate of broken bricks were selected as solid waste materials. Steel slag was used to replace cement cementitious materials, and broken bricks were used to replace crushed stones in concrete. Oxidized graphene based solid waste recycled concrete with different steel slag and broken brick substitution rates was prepared. The influence of solid waste materials on the mechanical properties, durability, and failure mode of recycled concrete was tested. The results showed that the compressive strength and flexural strength of recycled concrete with a steel slag replacement rate of 20% reached their maximum values, which were 41.50 and 4.50 MPa, respectively. The compressive strength and flexural strength of recycled concrete with a brick replacement rate of 30% reached their maximum values, which were 40.40 and 4.12 MPa, respectively. The failure mode of all specimens was a pyramid shape with four corners. As the replacement rate of steel slag increased, the number of cracks decreased. After the replacement rate of broken bricks increased, the overall strength of the concrete decreased, and the damage was severe. As the replacement rate of steel slag increased, the dry shrinkage of concrete first decreased and then increased. The lowest dry shrinkage rate of concrete with a steel slag replacement rate of 20% was 85.1×10^-6, the increase in the replacement rate of broken bricks continued to increase the dry shrinkage rate of concrete, exacerbating the shrinkage phenomenon. The chloride ion diffusion coefficients of recycled concrete replaced by broken bricks and steel slag decrease first and then increase with the increase of substitution rate, when the substitution rate of steel slag and broken bricks was 30%, the chloride ion diffusion coefficients of both types of concrete were the lowest, with values of 1.33×10^-8 and 1.47×10^-8 cm/s, respectively.

H₂O₂, as an excellent oxidizing agent, has a wide range of applications in various fields. The reaction of oxygen and water driven by sunlight is considered one of the most valuable and environmentally friendly methods for producing H₂O₂. By using phenolic compounds with varying degrees of conjugation in a hydrothermal polymerization reaction, some hydroxyl groups with electron-donating properties are converted into carbonyl groups with electron-withdrawing properties, resulting in phenolic resins with different D-A (donor-acceptor) structural features. This adjustment of the planar conjugated structure optimizes the separation efficiency of photogenerated electrons and holes. Results show that in phenolic resins, benzene-like phenol units act as electron donors, while quinone-like phenol units serve as electron acceptors. By designing and modifying the molecular structure, resins containing different electron donors and acceptors are formed, which alters their light absorption properties, carrier separation characteristics, and redox behavior. As the C=O content in the quinone-type phenolic structure increases, the photocatalytic H₂O₂ generation rate improves. Among them, resorcinol-formaldehyde (RF) resins exhibit the best catalytic efficiency, with RF523 achieving a H₂O₂ production rate of up to 598 μmol/h under full-spectrum illumination. Research on molecular-level structural tuning of resin materials to enhance their photocatalytic performance can serve as an effective approach for improving the photocatalytic properties of organic semiconductors.

In order to solve the problems of low hydrogen storage capacity, high temperature and slow hydrogen absorption and emission rate of Mg-Ni hydrogen storage alloy, Mg-Ni alloy block was prepared by arc melting. Then Mg-Ni hydrogen storage alloy powder containing rGO was prepared by melt quenching and high-energy ball grinding. The microstructure and hydrogen storage properties of Mg-Ni hydrogen storage alloy were observed and analyzed by XRD, TEM and hydrogen absorption and emission experiments. The results show that the rGO-Mg-Ni hydrogen storage alloy is composed of Mg and Mg₂Ni crystalline/amorphous phases, and Mg₂NiH₄ and MgH₂ phases after hydrogen absorption and desorption. The hydrogen storage capacity of the composite powder is 4.10 wt% at 553 K and 4.32 wt% at 623 K at 3.5 MPa, respectively. The hydrogen absorption rates were 3.34 wt%/min and 1.57 wt%/min, respectively. The enthalpy change and entropy change of MgH₂ at 553 K are 79.62 kJ/mol and 142.13 J/(mol·K), respectively. rGO is loaded on the surface of Mg matrix in the form of a single substance, which plays a good dispersion effect and prevents the agglomeration of Mg-Ni alloy powder, which is easy to make H₂ react with the matrix, and the dehydrogenation activation energy of the hydrogen storage alloy powder is reduced to 101.38 kJ/mol.

In order to develop clean and sustainable renewable energy, the use of solar photocatalytic decomposition of aquatic hydrogen had become a research hotspot. In this study, indium oxide (In₂O₃)/tungsten-oxy-49 (W₁₈O₄₉) composite nanofibers were successfully prepared by solvothermal loading W₁₈O₄₉ nanosheets on In₂O₃ electrospinning nanofibers. Due to the strong light absorption capacity and special localized surface plasmon resonance effect (localized surface plasmon resonance, LSPR) of W₁₈O₄₉, the light absorption capacity of In₂O₃/W₁₈O₄₉ heterojunction nanofibers was also greatly improved. The results of photocatalytic hydrogen evolution test showed that the H₂ release rate of In₂O₃/W₁₈O₄₉ nanofibers during photocatalysis was 15.9 times and 4.7 times higher than that of pure In₂O₃ and W₁₈O₄₉ nanofibers, respectively. The improvement of photocatalytic performance could be attributed to the construction of In₂O₃/W₁₈O₄₉ heterojunction, which not only improved the carrier separation efficiency, but also increased the specific surface area and the reactive site of samples. After four cycles, the photocatalytic hydrogen evolution performance of In₂O₃/W₁₈O₄₉-2 did not decrease significantly, indicating that it possessed good stability. In₂O₃/W₁₈O₄₉ composite nanofibers were easy to prepare and exhibited high photocatalytic activity, which could be widely used in the field of photocatalytic hydrogen evolution.

Nitric acid was used for Surface modification of polypropylene fibers (PP) and four types of polypropylene fiber concrete (PP-1,PP-2,PP-3,PP-4) were prepared by adjusting the nitric acid treatment time (1, 2, 3, 4 h). The effect of nitric acid treatment time on the morphology and structure of polypropylene fibers was studied, and the influence of nitric acid surface modification on the mechanical properties and salt-freeze resistance of polypropylene fiber concrete was investigated. The results showed that nitric acid introduced more hydroxyl and amide functional groups into the surface modification of polypropylene fibers, resulting in an increase in surface roughness, a decrease in water contact angle, and an improvement in hydrophilicity. The interface morphology and failure mode of polypropylene fiber reinforced concrete treated with nitric acid have been improved. When the nitric acid treatment time was 3 h, the compressive strength, flexural strength, and fracture toughness of the PP-3 sample reached their maximum values of 27.6, 8.5, and 39.7 MPa, respectively, indicating the optimal mechanical properties. After 100 cycles of composite salt freezing, the mass loss rate of PP-3 sample was the lowest at 0.974%, the maximum relative dynamic elastic modulus was 82.24%, and the frost resistance was the strongest. EDS testing showed that compared to aggregates, mortar has a higher porosity and a looser structure, which is more susceptible to salt ion erosion.

In order to balance the fire resistance and mechanical properties of thermoplastic polyurethane (TPU), organic modified attapulgite (OATP) was prepared by silane grafting as a synergistic flame retardant. The intumescent flame retardant (IFR) system was constructed by compounding piperazine pyrophosphate (PAPP) and melamine polyphosphate (MPP) at a mass ratio of 3:1, and the intumescent flame retardant TPU composites were prepared by melt blending. The comprehensive properties of TPU composites were investigated by limiting oxygen index (LOI), vertical combustion test, thermogravimetric analysis, cone calorimeter, Raman spectroscopy and mechanical properties test. With 25 wt% IFR and 3 wt% OATP, TPU-4 obtained 33% LOI value and UL-94 V-0 rating, and the peak heat release rate (pHRR) and peak smoke release rate (pSPR) were only 122 kW/m² and 0.018 m²/s. In addition, due to the good interfacial compatibility between OATP and TPU matrix, the tensile strength and elongation at break of TPU-4 were 27.3% and 39.7% higher than those of TPU-2, respectively. The results show that a proper amount of OATP can form a good synergistic flame retardant effect with PAPP/MPP intumescent flame retardant system.

To investigate the influence of nano-SiO₂ content and polyester fiber content and length on the pavement performance of asphalt mixtures, through dynamic shear rheological tests and low-temperature bending creep stiffness tests, the rheological properties of nano-SiO₂ modified asphalt with varying dosages were evaluated, and the optimal dosage was determined. Subsequently, polyester fibers with different dosages and lengths were incorporated into nano-SiO₂ modified asphalt mixtures to prepare AC-13 samples for rutting tests, low-temperature bending tests, and water immersion Marshall tests. The Design-Expert software was used to conduct response analysis and optimal ratio design based on the test results. The results show that 4% nano-SiO₂ dosage exhibits the best improvement in the high and low-temperature performance of asphalt. Compared to nano-SiO₂, polyester fibers have a more significant effect on improving the low-temperature crack resistance of asphalt mixtures, while also significantly enhancing high-temperature stability and water stability. According to the prediction model and response surface optimization analysis, the optimal dosage and length of polyester fibers are 0.26% and 7.97 mm, respectively. Compared with the base asphalt mixture, the dynamic stability, flexural tensile strength, and Marshall residual stability of the mixture under this dosage are increased by 177.14%, 37.39%, and 10.88%, respectively.

Na₂HPO₄·12H₂O has a phase transition temperature of 35-36 ℃, which is similar to the human body temperature, and has a high latent heat of 230-280 J/g, which has great potential in fields closely related to human activities. In order to prepare Na₂HPO₄·12H₂O composite phase change materials with low content of nucleating agent and thickener, a new type of nucleating agent, potassium dihydrogen phosphate (PDP), was found through nucleating agent screening, and the addition of nano-TiO₂ with lower content was further studied to further improve supercooling. The effects of thickener types and dosages on the properties of substrates were studied and screened. A new thermally stable composite phase change material with Na₂HPO₄·12H₂O as the substrate and Na₂HPO₄·12H₂O + 1.25% PDP+1.5% nano TiO₂ + 1% PSSA (sodium polyacrylate) was prepared. The results show that the phase transition temperature is 35 ℃, the supercooling degree is 1.5 ℃, and the latent heat value is 203.19 J/g. After 100 cycles, there was no detailed change in the supercooling degree and phase transition temperature, and the latent heat value decreased to 192.85 J/g, which was about 97.5% of the initial one, showing excellent thermal stability and high use value.

In order to study the adsorption behavior of NO, NO₂, CO, H₂S, SO₂ on Mn modified graphene surface, in this paper, the first-principles plane-wave ultrasoft pseudopotentials of the density-functional theory is used to simulate the adsorption process. The adsorption energy, Mulliken distribution, differential charge density, total charge density and recovery time were calculated and compared with those of unmodified graphene. The results show that the Mn-modified graphene surface is more sensitive to the adsorption of 5 gases than the unmodified graphene surface. After adsorption of NO, NO₂, CO, H₂S, SO₂ on Mn-modified graphene containing one C-vacancy and two C-vacancy, chemical bonds are formed between the gas and the substrate, which is chemical adsorption. The order of the adsorption energy of the same substrate is: NO>NO₂>CO>SO₂>H₂S, and the order of the charge transfer quantity after adsorption is: NO₂>NO>CO>SO₂>H₂S. The increase of C vacancy decreases the interaction between Mn-modified graphene surface and gas. The recovery time of Mn-modified graphene substrate as a gas sensor at room temperature is predicted. This provides theoretical support and experimental guidance for the detection of toxic gases based on graphene substrate.

Adding conductive polymers to the hydrogel matrix is a simple and effective method to construct hydrogels with good conductivity and flexibility. However, the hydrophobicity of conductive polymers limits the development of conductive hydrogels. Hence, in this study, by polymerizing pyrrole (Py) onto cellulose nanocrystals (CNC) via a freezing interface polymerization method, a CNC-PPy composite was synthesized, improving the dispersion of PPy in water. Subsequently, polyvinyl alcohol (PVA) and CNC-PPy were mixed and subjected to freeze-thaw cycles to fabricate a conductive hydrogel. The hydrogel was then immersed in ferric chloride (FeCl₃) to create a PVA/CNC-PPy/FeCl₃ ion-electron conductive hydrogel with multiple cross-linking effects. The unique synergistic effect of CNC-PPy and FeCl₃ endows the hydrogel with high strength (tensile strength of (465 ± 28) kPa), good flexibility (elongation at break of 239%±39%), and excellent conductivity (2.89 mS/cm). Moreover, the hydrogel sensor can monitor body deformations such as joint bending and vocal cord vibrations. Therefore, this work provides a promising strategy for developing PVA-based hydrogels with excellent mechanical properties and conductivity.

Three different morphologies of MoS₂ nanomaterials, flaky, flower-like, and spherical, were prepared by using ultrasonic exfoliation, hydrothermal, and high-temperature calcination methods. These nanomaterials were then modified with a silane coupling agent to produce the modified nano MoS₂ (KMoS₂). The KMoS₂ was incorporated into epoxy resin to prepare lubricating coatings with different MoS₂ contents. The morphologies of the nanomaterials and the cross-sections of the coatings were characterized by using scanning electron microscopy. Ball-on-disc friction tests revealed that the coating with modified spherical MoS₂ exhibited the lowest coefficient of friction and smallest wear volume, demonstrating the best anti-wear and friction-reducing performance. Compared to pure epoxy resin coatings, the average coefficient of friction and wear volume of the 2% spherical KMoS₂ coating were reduced by 51.7% and 22.2%, respectively, and the micro-hardness was increased by 14.9%. The spherical MoS₂ nanoparticles were more easily introduced into the contact zone to form effective lubricating films, and the friction mechanism involved a combination of rolling and sliding friction.

A large-size aluminum-based high-boron composite sheet with a specification of 700 mm×500 mm×50 mm, 70 wt% boron content and a density of 1.87 g/cm³ was prepared by using the metal powder cold isostatic pressing method. MCNP6 was used to comparatively study the neutron shielding performance of high-boron aluminum-based composite materials, polyethylene, tungsten, iron, and lead under the radiation conditions of Watt spectrum neutron source. And using ²⁵²Cf neutron source to verify the neutron shielding effect of aluminum-based high-boron composite materials. The research results show that the experimental values of aluminum-based high boron composite materials are in good agreement with the simulated calculated values. Although the aluminum-based high-boron composite material has the weakest neutron shielding performance per unit thickness among the five materials, the neutron shielding effect of aluminum-based high-boron composite materials per unit mass within a thickness of 10 cm immediately adjacent to the neutron radiation source is second only to polyethylene materials. The use of aluminum-based high-boron composite materials in the high-temperature and high-radiation shielding layer close to the nuclear power reactor can effectively reduce the overall weight of the shielding layer.

Caprylic acid (CA) and hexadecanol (HD) were used as raw materials to prepare binary eutectic phase change materials by melt blending method. In order to solve the problems of poor thermal conductivity and easy leakage of fatty acids and fatty alcohols in practical application, expanded graphite (EG) with high thermal conductivity and porous structure was selected to prepare caprylic acid-hexadecanol/expanded graphite (CA-HD/EG) composite phase change material by vacuum adsorption method. The structure and properties of CA-HD/EG composite phase change material were characterized by leakage observation, scanning electron microscopy (SEM), differential scanning calorimeter (DSC), Fourier transform infrared spectrometer (FT-IR), freeze/melt cycle and thermogravimetric (TG) testing. The eutectic mass ratio of CA-HD binary phase change material is 86:14, and the phase change temperature and latent heat of the eutectic phase change material are 10.26 ℃ and 158.83 J/g, respectively. The thermal conductivity of the eutectic phase change material is 0.23 W/(m·K). The composite phase change material with 10% EG added show no leakage after heat treatment, whose phase change temperature and phase change latent heat are 9.27 ℃ and 139.29 J/g, respectively. When the density of the composite phase change material with EG is 800 kg/m³, its thermal conductivity is 2.05 W/(m·K), which is 7.91 times higher than that of CA-HD. FT-IR testing shows that EG and CA-HD are physically adsorbed. The 500 freezing/melting cycle experiment shows that the composite phase change material has good cycle stability. TG testing shows that the initial weight loss temperature of CA-HD/EG is 143.98 ℃, which is much higher than the actual application temperature and has good heat resistance.

By mixing ammonium polyphosphate (APP), melamine polyphosphate (MPP) and tris (2-hydroxyethyl) isocyanurate (THEIC) in a 3∶1∶1 mass ratio, an expandable flame retardant (IFR) was constructed. Organic modified attapulgite (OATP) was used as a synergistic flame retardant, and an expanded flame retardant LDPE material was prepared by melt blending method. The flame retardancy, thermal stability, and mechanical properties of the material were tested using limit oxygen index (LOI), vertical combustion test, thermogravimetric analysis (TGA), and cone calorimetry (CCT). The results showed that the LOI value of composite material LDPE 2 reached 30.5%, and UL-94 reached V-0 level. Compared with the original LDPE, the peak smoke release rate (pSPR) and total smoke release rate (TSR) of LDPE 2 decreased by 82% and 65%, respectively. Compared with LDPE 1 without OATP added, LDPE 2 showed a 67.2% increase in elongation at break and a 17.3% increase in tensile strength. Adding OATP in moderation to the IFR system not only significantly improves the flame retardant performance of LDPE materials, but also effectively suppresses the release of smoke, while improving the mechanical strength of the expanded flame retardant material, demonstrating good synergistic flame retardant and smoke suppression effects.

Natural rubber (NR) and butadiene rubber (BR) are easy to burn and have low thermal conductivity, which limits their application range. In this paper, flame retardants with core-shell structure and high thermal conductivity PMMA@ADP-CNTs were prepared by coating aluminum diethylhypophosphate (ADP) with polymethyl methacrylate (PMMA) and doping carbon nanotubes (CNTs). It was added to natural rubber and butadiene rubber (NR/BR) to prepare NR/BR composite. The structure and thermal properties of the flame retardants were analyzed by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The flame retardancy, mechanical properties and thermal conductivity of rubber composites were analyzed by cone calorimeter test (CCT), limiting oxygen index (LOI), thermal conductivity coefficient and tensile test. The results showed that CNTs were successfully embedded in the PMMA shell of the flame retardant. The LOI of rubber composite increased from 19.4% to 23.9%, and the peak heat release rate (pHRR) and total heat release rate (THR) decreased from 1465.6 kW/m² and 142.3 MJ/m² to 562.4 kW/m² and 83.1 MJ/m². The thermal conductivity is increased from 0.32 W/(m·K) to 0.43 W/(m·K), which had good flame retardant and thermal conductivity, and PMMA@ADP-CNTs could improve the effect of ADP on the mechanical properties of rubber composites.

In order to improve the luminescence performance of barium titanate materials, based on the concept of rare earth element doping, one-dimensional nanofibers of Pr³⁺ doped BaTiO₃ were prepared using the electrospinning process. The influence of the rare earth element Pr³⁺ doping concentration on the phase structure, morphology, and luminescence properties of these nanofibers was analyzed, along with the influencing factors and mechanisms. The test results show that the Pr³⁺ doped BaTiO₃ nanofibers prepared by electrospinning have good one-dimensional nanofiber morphology. At lower Pr³⁺ doping concentrations, the rare earth element Pr³⁺ can enter the crystal lattice of BaTiO₃ powder without forming new impurities. The fluorescence performance test results show that Pr³⁺ doping can significantly improve the luminescence performance of BaTiO₃ one-dimensional nanofibers. Pr³⁺ doping can provide relevant electronic transition energy levels, and the main emission peaks at 497 nm, 502 nm, 539 nm, 613 nm, 659 nm are derived from energy level transitions of ³P₀→³H₄, ³P₁→³H₅, ³P₀→³H₆, and ³P₀→³F₂, respectively. As the Pr³⁺ doping concentration increases, the fluorescence intensity of Ba_1-xPr_xTiO₃ one-dimensional nanofibers first increases and then decreases. This phenomenon can be attributed to the interaction between the BaTiO₃ crystal lattice and Pr³⁺ when doping at lower Pr³⁺ concentrations. When Pr³⁺ doping is higher, the distance between the BaTiO₃ crystal lattice and Pr³⁺ decreases, resulting in some energy transfer to the quenching center, which leads to a decrease in the fluorescence intensity of Pr³⁺ doped BaTiO₃ one-dimensional nanofibers.

To provide the basis for the pre-treatment process of Ni-Ti alloy before cold drawing, the effect of aging process at different temperatures on the martensitic transformation behavior and superelasticity of 50.8Ni-Ti alloy was studied. The results show that after aging at 350 ℃ for 5 h, Ms of Ni-Ti alloy increases gradually due to R phase transformation induced by precipitated phase. After aging at 450 ℃, the phase transition type of Ni-Ti alloy changes from two-step phase transition to (B2→B19′/B19′→R→B2) phase transition with the increase of aging time. The Ms increased overall but still did not reach room temperature, the Ms rose from -60 ℃ (1 h) to 11.1 ℃ (20 h). After aging at 550 ℃, because the size of precipitated phase increases with the increase of temperature, the phase transformation type of aging Ni-Ti alloy changes from (B2→R→B19′/B19′→R→B2) type phase transition to (B2→B19′/B19′→B2) type phase transition, and the Ms rises from -32.53 ℃ (1 h) to 29.17 ℃ (20 h). Ni-Ti alloy has superelasticity when the aging temperature is 350 ℃ and the aging time is 1, 2, 5 h and 450 ℃ for 1 h respectively. When the aging temperature is 450 ℃ for 5 h and 550 ℃ for 5 h, the alloy part has superelastic condition. Under other aging conditions, during the loading process of the alloy, except for part of the martensitic elastic deformation recovery, the residual strain is 3-5%. The alloy has no superelasticity at room temperature (25 ℃). In summary, combined with the cold drawing production process, the martensitic phase at room temperature cannot be obtained by aging at different temperature for a short time, and the aging treatment can be selected to introduce R-phase to remove the superelasticity. The optimal cold drawing pretreatment scheme for 50.8Ni-Ti alloy was obtained by aging at 550 ℃ for 1 h.

Shape Memory Alloys (SMAs) possess unique advantages, including high actuation stroke, high energy density, and strong environmental adaptability, which contribute to their broad prospects in smart structures and intelligent actuation. However, the inherent nonlinear characteristics of SMA materials, such as hysteresis and creep, significantly impact actuation effectiveness and control accuracy. Consequently, this study focuses on SMA wire actuators, performing both identification and experimental validation of drive models based on the Prandtl-Ishlinskii (PI) hysteresis model and the lgt creep operator. First, a theoretical model of SMA wire is constructed based on the Liang-Rogers constitutive equation to provide data for model identification. Subsequently, the PI hysteresis modeling method is employed to develop the hysteresis characteristic model of SMAs. To address the limitations of traditional PI models in fitting odd-symmetric and non-convex hysteresis characteristics, the lgt creep operator is integrated into the conventional PI model to enhance its fitting accuracy, with the effectiveness of the algorithm verified through simulation data from the theoretical model. Finally, an experimental platform for SMA driving tests is established, enabling online identification of hysteresis and creep drive models using experimental data. The results demonstrate that the proposed methods effectively enhance the identification accuracy of SMA drive models, thereby providing new theoretical support for improving both SMA drive accuracy and control effectiveness.