Abstract: A carbon-based conductive film-based ultralight wide-angle absorbing metamaterial with full-frequency absorption within 2-18 GHz, including a first dielectric substrate, a first carbon-based conductive film array structure layer, a second dielectric substrate, a second carbon-based conductive film array structure layer, a third dielectric substrate, and a third carbon-based conductive film array structure layer, which are laminated in sequence with the first dielectric substrate as a bottom. The first, second, and third carbon-based conductive film array structure layers are each composed of discrete carbon-base conductive film patches arranged in a periodic array. A method for preparing such absorbing metamaterial is also provided.

Abstract: A thermal compensation design and implementation method for near-net-shape molding of a thermoset composite part based on temperature and curing degree fields is provided. A minimum symmetric unit model is established based on sizes of the part and a mold and ambient temperature. A curing kinetic model and a heat transfer model are established. A molding temperature curve is written into a subprogram. A simulated thermal compensation is performed on a region whose temperature is lower than a molding temperature with a difference of greater than or equal to 5% of the molding temperature until the temperature difference of individual regions is less than 5% of the molding temperature. The simulated thermal compensation is then performed on those regions with a curing degree less than or equal to 0.9. A thermal compensation device is assembled according to the thermal compensation scheme for experimental verification.

Abstract: An artificial intelligence (AI)-based method for non-contact measurement of sheet resistance of a conductive film material, in which a non-contact measurement method commonly used in the field of electromagnetic wave absorbing-materials is adopted to measure reflection loss data of a wave-absorbing structure Salisbury screen composed of a film material and a substrate; a program-controlled AI model is adopted to predict reflection losses of Salisbury screens with different sheet resistances; the sheet resistance is continuously adjusted, and the range is gradually narrowed to fit the measured reflection loss data; and the sheet resistance of the conductive film materials is inversely deduced.

Abstract: An high-velocity impact-resistant wave-transparent composite, including an upper composite layer, a lower composite layer, and a bio-inspired nacre-like toughening structure arranged therebetween. The toughening structure has a soft-hard alternating nacre-like structure, and is made from a low dielectric constant sheet material and a resin. The upper composite layer and the lower composite layer are each independently made of a fiber-reinforced resin composite, a foam material, or a honeycomb material. A preparation method of the high-velocity impact-resistant wave-transparent composite is further provided.

Abstract: A lightweight absorption-transmission integrated metamaterial to electromagnetic waves with polarization stability and wide-incident-angle stability, which has a symmetric structure including at least one square frequency-selective structure-unit arranged periodically. The square frequency-selective structure-unit includes a first dielectric substrate, a metal array structure layer, a second dielectric substrate, a first carbon-based conductive film array structure layer, a third dielectric substrate, and a second carbon-based conductive film array structure layer, which are laminated in sequence with the first dielectric substrate as the bottom. A method for preparing such lightweight absorption-transmission metamaterial to electromagnetic waves is also provided.

Abstract: A lightweight, low-thickness, durable, and reliable multi-band radar stealth-bulletproof integrated metamaterial includes a ceramic layer, an ultrahigh molecular weight polyethylene (UHMWPE) fiber composite bulletproof layer, a graphene-based metamaterial filter layer, an UHMWPE fiber composite attenuation layer, and a carbon fiber composite reflective layer stacked in sequence. The two UHMWPE fiber composite layers are configured to attenuate radar waves. The circuit resonance of the graphene-based metamaterial filter layer is configured to generate a passband and a stopband simultaneously. The bulletproof layer and the attenuation layer are controlled by the graphene-based metamaterial filter layer in terms of working conditions in different radar frequency bands to establish a structure capable of generating ?/4 resonance at both low and high frequencies, so as to arrive at a stealth-bulletproof integrated metamaterial with small thickness and excellent dual-band radar wave absorption capability.

Abstract: A method for evaluating reinforcement effect and efficiency of a filler on natural rubber based on particle size of bound rubber particles formed by the filler and natural rubber particle in a natural rubber latex, in which the natural rubber latex and the filler are mixed and diluted to obtain a to-be-detected emulsion, and an average particle size of bound rubber particles is measured using an instrument; a ratio of the average particle size to an average particle size of natural rubber particles in a pure rubber latex emulsion with the same concentration is calculated; the reinforcement effect of the filler on the natural rubber is evaluated based on the ratio; a function expression is established to derive a stress at definite elongation of various filler-modified natural rubber vulcanizates; and according to the function expression, the reinforcement efficiency of the filler on the natural rubber is evaluated.

Abstract: An optimization method for molding mold and filling process of resin transfer molding (RTM) to form fiber fabric reinforced resin-based composite parts is provided. A simulation platform is used to simulate the mold filling process of RTM process. Brinkman equations are used to describe a flow of resin in fiber fabric. Numbers and positions, process parameters and material parameters of an injection gate and a discharging gate of the molding mold are set, and then the mold filling process is simulated. Darcy's law is utilized to determine a required time and a mold filling effect of the mold filling with the resin. Finally, a molding mold structure and the filling process of RTM to form fiber fabric reinforced resin-based composite part with high production efficiency and good quality are obtained.

Abstract: A thermal compensation design and implementation method for near-net-shape molding of a thermoset composite part based on temperature and curing degree fields is provided. A minimum symmetric unit model is established based on sizes of the part and a mold and ambient temperature. A curing kinetic model and a heat transfer model are established. A molding temperature curve is written into a subprogram. A simulated thermal compensation is performed on a region whose temperature is lower than a molding temperature with a difference of greater than or equal to 5% of the molding temperature until the temperature difference of individual regions is less than 5% of the molding temperature. The simulated thermal compensation is then performed on those regions with a curing degree less than or equal to 0.9. A thermal compensation device is assembled according to the thermal compensation scheme for experimental verification.

Abstract: An artificial intelligence (AI)-based method for non-contact measurement of sheet resistance of a conductive film material, in which a non-contact measurement method commonly used in the field of electromagnetic wave absorbing-materials is adopted to measure reflection loss data of a wave-absorbing structure Salisbury screen composed of a film material and a substrate; a program-controlled AI model is adopted to predict reflection losses of Salisbury screens with different sheet resistances; the sheet resistance is continuously adjusted, and the range is gradually narrowed to fit the measured reflection loss data; and the sheet resistance of the conductive film materials is inversely deduced.

Abstract: A method for integrally preparing urea-formaldehyde (UF)-based multi-nutrient biodegradable polymeric slow-release (SR) liquid and granular fertilizers is provided. A hydroxymethylurea solution is prepared, and a part of the hydroxymethylurea solution is added to a reactor for reaction to obtain the UF-based multi-nutrient biodegradable polymeric SR liquid fertilizer. The rest of the hydroxymethylurea solution is fed into a reaction-extrusion integrated machine for reactive extrusion to obtain a UF polymer through the polycondensation reaction, which is extruded, dried and granulated to obtain the UF-based multi-nutrient biodegradable polymeric SR granular fertilizer. A method for applying such liquid and granular fertilizers is also provided.

Abstract: A method for preparing a graphene-modified natural rubber (NR) with an interfacial interaction based on a free radical annihilation reaction is provided. In the process of reducing graphene oxide (GO), a free radical scavenger is loaded on a surface of reduced graphene oxide (rGO). An rGO-modified NR composite is prepared through aqueous synergistic aggregating precipitation process and mechanical blending. The free radical scavenger loaded on the rGO particles are capable of annihilating macromolecular free radicals generated by NR macromolecules due to an action of heat and/or force during the mixing and milling processes, an enhancement effect of the free radical annihilation reaction on an interfacial interaction between graphene and NR is great, so as to obtain a graphene-modified NR composite with improved strength and toughness.

Abstract: A method for preparing a uniformly-cured solid loading tire from a high-modulus graphene oxide/natural rubber composite is provided. A high-modulus graphene oxide/carbon black/natural rubber mixture sheet and two high-viscosity graphene oxide/carbon black/natural rubber mixture sheets are prepared, where a weight ratio of graphene oxide to natural rubber to carbon black to an interface modifying agent to an anti-aging agent to an antioxidant to a vulcanization accelerator to an activator to a softener to a vulcanizing agent is 0.5-5:100:40-120:1-20:1-10:1-10:1-20:1-20:1-20:1-20. The high-modulus rubber mixture sheet is sandwiched between the two high-viscosity rubber mixture sheets to form a sandwich-structure rubber mixture laminate, which is then processed into a strip. The strip is wound along a surface of a hub of a loading wheel, and then the hub is transferred to a mold for vulcanization to obtain the desired tire.

Abstract: A lightweight absorption-transmission integrated metamaterial to electromagnetic waves with polarization stability and wide-incident-angle stability, which has a symmetric structure including at least one square frequency-selective structure-unit arranged periodically. The square frequency-selective structure-unit includes a first dielectric substrate, a metal array structure layer, a second dielectric substrate, a first carbon-based conductive film array structure layer, a third dielectric substrate, and a second carbon-based conductive film array structure layer, which are laminated in sequence with the first dielectric substrate as the bottom. A method for preparing such lightweight absorption-transmission metamaterial to electromagnetic waves is also provided.

Abstract: An optimizing method for a molding process of a part made of a fiber-reinforced polymer composite is provided. A finite element method is adopted to perform thermochemical analysis of a macroscopic model of the part and thermomechanics analysis of a microscopic model of the part, so as to simulate temperature gradient, curing degree, and residual stress of the part during the molding process. A genetic algorithm is executed, with simultaneous minimization of temperature gradient, molding time, and residual stress as an optimization goal and a curing process curve as a parameter variable, to achieve the simultaneous multi-objective optimization of molding process parameters, so as to obtain an optimized molding process.

Abstract: An high-velocity impact-resistant wave-transparent composite, including an upper composite layer, a lower composite layer, and a bio-inspired nacre-like toughening structure arranged therebetween. The toughening structure has a soft-hard alternating nacre-like structure, and is made from a low dielectric constant sheet material and a resin. The upper composite layer and the lower composite layer are each independently made of a fiber-reinforced resin composite, a foam material, or a honeycomb material. A preparation method of the high-velocity impact-resistant wave-transparent composite is further provided.

Abstract: A method for preparing a weathered coal-derived humic acid/urea-formaldehyde slow-release fertilizer granule by reactive extrusion process with depolymerization-activation-polycondensation trinity is provided. In an alkaline environment, paraformaldehyde is depolymerized into formaldehyde small molecules, which react with urea to form monohydroxymethylurea and dihydroxymethylurea. Under the strong shearing action of screws of the twin-screw reactive extruder, the macromolecular weathered coal-derived humic acid is depolymerized into relatively small molecule weathered coal-derived humic acid, and abundant active carboxyl groups are exposed, some of which immediately undergo dehydration condensation with —NH2 on the urea-formaldehyde molecule produced by the polycondensation of hydroxymethylurea during the reactive extrusion process to generate weathered coal-derived humic acid/urea-formaldehyde and its granules.

Abstract: A lightweight, low-thickness, durable, and reliable multi-band radar stealth-bulletproof integrated metamaterial includes a ceramic layer, an ultrahigh molecular weight polyethylene (UHMWPE) fiber composite bulletproof layer, a graphene-based metamaterial filter layer, an UHMWPE fiber composite attenuation layer, and a carbon fiber composite reflective layer stacked in sequence. The two UHMWPE fiber composite layers are configured to attenuate radar waves. The circuit resonance of the graphene-based metamaterial filter layer is configured to generate a passband and a stopband simultaneously. The bulletproof layer and the attenuation layer are controlled by the graphene-based metamaterial filter layer in terms of working conditions in different radar frequency bands to establish a structure capable of generating ?/4 resonance at both low and high frequencies, so as to arrive at a stealth-bulletproof integrated metamaterial with small thickness and excellent dual-band radar wave absorption capability.

Abstract: A lightweight, ballistic and blast-resistant multi-phase composite armor material based on a high-toughness heterogeneous interfacial layer, including a crack-arresting layer, a bullet-breaking layer, an energy-absorbing layer, and a support layer. The crack-arresting layer, the bullet-breaking layer, the energy-absorbing layer, and the support layer are stacked in sequence from a bullet-accepting side to the inside. Adjacent two layers are bonded with an adhesive film layer. The crack-arresting layer and the support layer are both made of a carbon fiber composite. The bullet-breaking layer is made of ceramic. The energy-absorbing layer is made of an ultra-high molecular weight polyethylene fiber composite. The adhesive film layer is made of a high-toughness heterogeneous interfacial adhesive.

Abstract: An efficient microwave-assisted preparation method with one-step simultaneous reduction/embedding of a metal monatomic-doped reduced graphene oxide dielectric material. A metal salt aqueous solution is added to a graphene oxide aqueous dispersion to obtain a mixed dispersion. The mixed dispersion is mechanically stirred, such that the metal salt fully interacts with the graphene oxide, and the metal ions are uniformly loaded on a surface of the graphene oxide sheets through the interaction between metal ions and the oxygen-containing functional groups of the graphene oxide. The mixed dispersion is freeze-dried to obtain a metal salt/graphene oxide complex, which is subjected to a microwave treatment in the presence of an initiator in a microwave oven to allow reduction to obtain the metal monatomic-doped reduced graphene oxide dielectric material. An application of the metal monatomic-doped reduced graphene oxide dielectric material is also provided.