North University of China

Shanxi Zhongbei New Material Technology Co., Ltd.

Shanxi Zhohngbei New Material Technology Co., Ltd.

Northen University of China

Guizhe Zhao

Yaqing Liu

Yang Xiang

Chaoyang Wu

Guanyu Han

Qihui Chen

Mingshan Gong

Wenqi Wang

Shuaishuai Cheng

Wei Zhang

Peng Gao

Ruikui Du

Yanan Liu

Yu Zhang

Lifeng Zhou

Denghui Wu

Taian Chen

Rongyao Tao

Kai Wen

Haoyu Duan

Yong Gao

Yingfang Tong

Xu Li

Dongdong Cheng

Hongji Duan

Xiaoyuan Duan

This disclosure relates to slow- and controlled-release fertilizers, and more particularly to a device and a method for industrialized continuous and simplified preparing a urea-formaldehyde slow-release nitrogen fertilizer or a urea-formaldehyde-based slow- and controlled-release multi-nutrient fertilizer. Hydroxymethylurea is produced through the reaction extrusion of urea and formaldehyde. Through the self-ploycondensation of the hydroxymethylurea or the co-polymerization of the hydroxymethylurea and a modifier in a reactive extruder, the urea-formaldehyde slow-release nitrogen fertilizer or the urea-formaldehyde-based slow- and controlled-release multi-nutrient fertilizer is prepared.

Device and method for industrialized continuous and simplified preparation of urea-formaldehyde slow-release nitrogen fertilizer or urea-formaldehyde-based slow- and controlled-release multi-nutrient fertilizer

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.

Carbon-based conductive film-based ultralight wide-angle absorbing metamaterial with full-frequency absorption within 2-18 GHz and preparation method thereof

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.

Optimizing method for molding process of fiber-reinforced polymer composite parts

A method for preparing a graphene-containing ultra-fine powdered natural rubber masterbatch, including: mixing a diluted graphene oxide dispersion with an anionic surfactant to obtain a modified graphene oxide dispersion; mixing the modified graphene oxide dispersion with a natural rubber latex suspension to obtain a mixed emulsion; and subjecting the mixed emulsion to spray drying to obtain the ultra-fine powdered natural rubber masterbatch with a particle size of less than 5 μm. This application further provides a method for preparing a graphene-modified natural rubber nanocomposite, including: mixing the ultra-fine powdered natural rubber masterbatch with natural rubber block, and carbon black.

Efficient and cost-effective method for preparing ultra-fine powdered natural rubber masterbatch with high graphene content and use thereof

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.

Method for evaluating reinforcement effect and efficiency of filler on natural rubber based on particle size of bound rubber particle formed by the filler and natural rubber latex

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.

Integrated-preparation and application methods of urea-formaldehyde (UF)-based multi-nutrient biodegradable polymeric slow-release (SR) liquid and granular fertilizers

Disclosed is a method for preparing a nitrogen-rich or nutritious straw-based slow-release fertilizer through In-Situ straw modification/reactive extrusion integrated continuous process. In the method, the liquid reaction precursor of a nitrogen-containing biodegradable slow-release fertilizer is mixed with crop straw to obtain a reaction mixture, or the liquid reaction precursor of a nitrogen-containing biodegradable slow-release fertilizer, crop straw and a soluble fertilizer are mixed to obtain a reaction mixture. The reaction mixture is subjected to extrusion in a screw extruder to produce the nitrogen-rich or nutritious straw-based slow-release fertilizer.

Method for preparing nitrogen-rich or nutritious slow-release fertilizer through in-situ straw modification/reactive extrusion integrated continuous process

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.

Method for preparing uniformly-cured solid loading tires from high-modulus graphene oxide/natural rubber composite

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.

Thermal compensation design and implementation method for a near-net-shape (NNS) molding of thermoset composite part based on temperature field and curing degree field

A vulcanizing agent-modified graphene prepared through an in-situ chemical deposition process and a controllable crosslinked natural rubber composite containing the same. In the preparation of the vulcanizing agent-modified graphene, graphene oxide is coated on a spherical thermal-conductive functional particle through the chemical bonding to obtain a 3D graphene particle; and a vulcanizing agent is adsorbed on the 3D graphene particle through π-π conjugation by an in-situ chemical deposition process to obtain a vulcanizing agent-modified graphene particle. Further, the vulcanizing agent-modified graphene particle is mixed with natural rubber latex, and undergoes synergistic coagulation in water to form a graphene masterbatch, which is further processed into the controllable crosslinked natural rubber composite by adding a certain amount of natural rubber block, rubber additive and reinforcing filler.

Vulcanizing agent-modified graphene prepared through an in-situ chemical deposition process, and controllable crosslinked natural rubber composite comprising the same

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.

Artificial intelligence (AI)-based method for non-contact measurement of sheet resistance of a conductive film material

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.

High-velocity impact-resistant wave-transparent composite with bio-inspired nacre-like interlaminar toughening structure, and preparation method thereof

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.

Lightweight absorption-transmission integrated metamaterial to electromagnetic waves with polarization stability and wide-incident-angle stability, and preparation method thereof

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 λ/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.

Lightweight, low-thickness, durable and reliable multi-band radar stealth-bulletproof integrated metamaterial

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 —NHon 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.

Method for preparing weathered coal-derived humic acid/urea-formaldehyde slow-release fertilizer granules by reactive extrusion process with depolymerization-activation-polycondensation trinity and fertilization method

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Taiyuan, China

Guizhe Zhao