Resorcinol–formaldehyde (RF) and graphene oxide (GO) aerogels have found a variety of applications owing to their excellent properties and remarkable flexibility. However, the macroscopic and ...controllable synthesis of their composite gels is still a great challenge. By using GO sheets as template skeletons and metal ions (Co2+, Ni2+, or Ca2+) as catalysts and linkers, the first low‐temperature scalable strategy for the synthesis of a new kind of RF–GO composite gel with tunable densities and mechanical properties was developed. The aerogels can tolerate a strain as high as 80 % and quickly recover their original morphology after the compression has been released. Owing to their high compressibility, the gels might find applications in various areas, for example, as adsorbents for the removal of dye pollutants and in oil‐spill cleanup.
A composite aerogel consisting of resorcinol/formaldehyde and graphene oxide (GO) could be synthesized on large scale by using GO sheets as template skeletons and metal ions (Co2+, Ni2+, or Ca2+) as catalysts and linkers. These compressible aerogels can tolerate a strain as high as 80 % and quickly recover their original shapes.
The interaction and action mechanism of starch with different phenolic compounds were investigated. By using scanning electron microscope, nuclear magnetic resonance, Fourier transform infra-red ...spectroscopy and thermogravimetric analysis, phenolic compounds exhibited the significant effects on the morphology, intensity of hydrogen bond, crystalline structure and thermal stability of starch, respectively. Furthermore, according to the analysis of molecular dynamics simulation by using short-chain glucose (SGS) as model, phenolic compounds could change the spatial configuration of starch, and had the obvious effects on the formation of hydrogen bonds (including intra- and intermolecular hydrogen bonds) and the strength of binding free energy. Meanwhile, epigallocatechin gallate possessed the strongest capacity to change the spatial configuration of starch with the consistent hydrogen bond occupancy and the lowest binding free energy. All present results suggested that phenolic compounds might be potentially utilised for improving the quality of starch in food industry.
The potential uses of Ligustrum robustum (Rxob.) Blume extract as a natural antioxidant to protect the quality of different oils during storage and frying process were studied. The results showed ...that L. robustum extract has been shown to retard the decline in the quality of both oils based on the tests of acid value, peroxide value, p‐anisidine value, color, volatile flavor, and fatty acid compositions, and the protective effect of L. robustum extract on the quality of peanut oil was better than that of palm oil. By the component analysis, L. robustum extract was found to have a total phenols content of 140.75 ± 1.52 mg/g, and ligurobustoside C was identified as the main phenolic compound. The thermogravimetric and differential scanning calorimetry results showed that L. robustum extract enhanced the oxidative stability of peanut and palm oils. In addition, Fourier transform infrared results indicated that L. robustum extract had protective effects on the C=C bond and ester bond of oil molecule. Moreover, by using electron spin resonance technique, L. robustum extract showed the ability to inhibit and scavenge alkyl‐free radicals in both oils. The present results suggested that L. robustum extract may protect the quality of oils during the storage and frying process by inhibiting the oxidation of unsaturated fatty acids and might be a potential natural antioxidant in the food industry.
Practical Applications
The excellent antioxidant ability of Ligustrum robustum (Rxob.) Blume extract on the oxidation of different oils and its low price indicated that it could be used as a new low‐cost natural antioxidant in oil processing.
Inspired by microstructures of polar bear hair, herein, we describe a simple solution-based strategy to fabricate a macroscopic-scale and lightweight carbon tube aerogel with super-elasticity and ...excellent thermal insulation. The microstructure-derived thermal conductivity and super-elasticity are strongly dependent on the shell thickness of the interconnected tubes, as well as the aperture of the aerogel. Remarkably, the optimized aerogel can maintain structural integrity after more than one million compress-release cycles at 30% strain and 10,000 cycles at 90% strain. Moreover, this biomimetic aerogel offers a fast and accurate dynamic piezoresistive response to broad bandwidth frequency forces. Particularly, the super-elasticity is further confirmed by its fastest rebounding speed of 1,434 mm s−1 among the traditional elastic materials measured by a standard falling steel ball. Furthermore, the optimized minimum thermal conductivity is as low as 23 mW m−1 K−1 which performs better than the thermal conductivity of dry air.
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•Bioinspired fabrication of a macroscopic-scale lightweight carbon tube aerogel.•The CTA materials show super-elasticity with the rebounding speed of 1,434 mm/s.•The microstructure-derived CTA materials show excellent thermal insulation property.
Their hollow, lightweight, and non-wettable hair helps polor bears resist their extremely cold environment. Inspired by the microstructure of polar bear hair, we fabricated the carbon tube aerogel (CTA), which shows all merits of polar bear hair, such as being lightweight, waterproof, and thermally insulating. Briefly, the CTA composed of hollow carbon tube fibers is lightweight with the lowest density of only 8 kg/m3, and is also waterproof with a contact angle of 146°. The lowest thermal conductivity of the CTA is only 23 mW m−1 K−1. Remarkably, the bioinspired CTA materials show better performance than the polar bear hair. The interconnected network structure of the CTA is endowed with super-elasticity and fatigue resistance, which is confirmed by the rebounding speed of 1,434 mm/s and structural integrity after more than 10,000,000 cyclic compressions at 30% strain. The bioinspired design of macroscopic synthesis of CTA opens a window for designing high-performance material.
Zhan and colleagues have developed a simple solution-based strategy to fabricate a macroscopic-scale carbon tube aerogel (CTA) with super-elasticity and thermal insulation. The CTA material consists of plentiful uniform carbon tube fibers, which are interconnected with each other. The hollow structure of the CTA has the ability to decrease thermal conductivity, which is lower than most reported tube materials. Meanwhile, the junctions between carbon tube fibers endow the CTA with super-elasticity and fatigue resistance.
Solar thermal conversion (STC) evaporation is a practical and sustainable technology for seawater desalination and sewage abatement. However, both the limited evaporation efficiency and long-term ...conversion stability restrain its practical application. Herein, a lotus morphology-inspired biomimetic evaporator (MBE) with Janus wettability and bimodal pores is well designed for high-rate and enduring STC evaporation. Just like lotus leaves, the hydrophobic surface of the MBE cuts off the capillarity of water, hence achieving high-efficient salt resistance and solar absorption, while the hydrophilic substance provides fast water transportation. The bimodal-pore structures formed by incorporating lotus root-like mesopores into the 3D truss-like macropores effectively decrease density and thermal conductivity for self-floating and thermal regulation. This results in a low water vaporization enthalpy of 1846 J g−1, leading to a much higher evaporation rate at the same conversion efficiency. This work may open new avenues for developing high-performance evaporation systems.
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Lotus morphology-inspired biomimetic evaporator for efficient evaporationJanus surface and bimodal pores are identified for long-term desalinationWell-designed carbon with low thermal conductivity and functional wettability
Solar thermal conversion (STC) evaporation is a practical and sustainable technology for seawater desalination and sewage abatement. Here, Zhao et al. design a lotus morphology-inspired biomimetic evaporator with Janus wettability and bimodal pores for high-rate and enduring STC evaporation. This work provides a biomimetic strategy for designing energy conversion materials with Janus surfaces, bimodal pores, and low water vaporization enthalpy.
Abstract
Lithium metal is one of the most promising anode materials for high-energy-density Li batteries. However, low stability caused by dendrite growth and volume change during cycling hinders its ...practical application. Herein, we report an ingenious design of bio-inspired low-tortuosity carbon with tunable vertical micro-channels to be used as a host to incorporate nanosized Sn/Ni alloy nucleation sites, which can guide Li metal's plating/stripping and meanwhile accommodate the volume change. The pore sizes of the vertical channels of the carbon host can be regulated to investigate the structure–performance correlation. After compositing Li, the bio-inspired carbon host with the smallest pore size (∼14 μm) of vertical channels exhibits the lowest overpotential (∼18 mV at 1 mA cm−2), most stable tripping/plating voltage profiles, and best cycling stability (up to 500 cycles) in symmetrical cells. Notably, the carbon/Li composite anode is more rewarding than Li foil when coupled with LiFePO4 in full cells, exhibiting a much lower polarization effect, better rate capability and higher capacity retention (90.6% after 120 cycles). This novel bio-inspired design of a low-tortuosity carbon host with nanoalloy coatings may open a new avenue for fabricating advanced Li-metal batteries with high performance.
The effect of tea polyphenols (TPs) on noodles quality was investigated, and the interaction mechanism between catechins and gliadins was explored. With TPs addition, noodles showed the significant ...changes in physicochemical and sensory properties. The water absorption, tensile strength and elasticity increased by 1.35%, 4.98%, 28.51% with 0.5% of TPs, and then decreased with the increasing of TPs. According to the determinations of surface hydrophobicity, spatial structure, thermal properties, amidogen and sulfhydryl content, the structure and properties of gliadin were affected by catechins. Esterified catechins tended to disrupt gliadin structures and non-esterified catechins polymerised gliadin molecules. Furthermore, molecular docking results indicated that catechins interacted with gliadin mainly by hydrogen bonds and hydrophobic action. The reactivity of catechins with gliadin was in the sequence as: epigallocatechin gallate > epicatechin gallate > epigallocatechin > epicatechin, which was based on the account of gallate and B-ring hydroxyl number discrepancy. All results suggested that catechins affected greatly on gliadin, and TPs were potentially used to improve the quality of flour products.
High-temperature barrier coatings protect metals and alloys from oxidization, delay property degradation and increase their service lifetime. Here we demonstrate a vermiculite clay-based ...oxidation-resistant coating on metal, using copper as an example. Dispersions of few-layer vermiculite sheets with lateral dimension in the range of microns to tens of microns are obtained in a two-step mechanical-chemical exfoliation approach, using vermiculite mineral as the starting material. The dispersion of these high aspect ratio two-dimensional sheets can be directly spray-coated on Cu foils to form a continuous and transparent thermal barrier film without the need for any binder materials. After heating in air at 400 °C for 24 h, vermiculite protected Cu foils did not show any significant sign of oxidation or degradation in mechanical and electrical properties, while uncoated Cu foils were completely destroyed.
Few-layer vermiculite sheets obtained by a two-step mechanical-chemical exfoliation approach for oxidation-resistant coating.
Educational data mining is an interdisciplinary subject of computer science, statistics and pedagogy, and it mainly deals with the problems of educational research and teaching practice through the ...theory and technology of computer science and statistics.For example, it can reduce the learning cost of students and the educational cost of teachers as much as possible under the condition of obtaining the maximum learning gain.The rapid development of computer-assisted education environments and online education platforms has generated a wealth of data, which has also posed a major challenge, of course, but it cannot provide resources for students' specific needs.Knowledge tracing is an individual method for recommending teaching resources and diagnosing learning paths in the field of intelligent tutoring education.With the time going on, students' knowledge states can be mo-deled to predict their future performance based on their historical response sequences.This paper focuses on the analysis of relevant liter
Nanostructured metal sulfide–amine hybrid materials have attracted attention because of their unique properties and versatility as precursors for functional inorganic nanomaterials. However, ...large‐scale synthesis of metal sulfide–amine hybrid nanomaterials is limited by hydrothermal and solvothermal preparative reaction conditions; consequently, incorporation of such materials into functional nanomaterials is hindered. An amine molecule‐assisted refluxing method was used to synthesize highly uniform zinc sulfide⋅(diethylenetriamine)0.5 (ZnS⋅(DETA)0.5) hybrid nanosheets and nanobelts in a large scale. The obtained ZnS⋅(DETA)0.5 hybrid nanomaterials can be used as efficient precursors to fabricate functional ZnS nanomaterials and carbon encapsulated sulfur (S@C) nanocomposite cathodes for Li–S batteries.
Semiconducting hybrid nanomaterials for sulfur nanocomposite cathodes were prepared by an amine molecule‐assisted refluxing technique. Uniform zinc sulfide⋅(diethylenetriamine)0.5 hybrid nanomaterials were synthesized in a 15 g yield per one‐pot reaction. The material was used to fabricate functional zinc sulfide nanomaterials and encapsulated sulfur nanocomposites.
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