Hydrogel-based strain sensors have been attracting immense attention for wearable electronic devices owing to their intrinsic soft characteristics and flexibility. However, developing hydrogel sensors with hightensile strength, stretchability, and strain sensitivity remains a great challenge. Herein, we report a technique to synthesize highly sensitive hydrogel-based strain sensors by integrating carbon nanofibers (CNFs) with a double-network (DN) polymer hydrogel matrix comprising of a physically cross-linked agar network and a covalently cross-linked polyacrylamide (PAAm) network. The resultant nanocomposite sensors display superior piezoresistive sensitivity with a hightrue gauge factor (GFT = 1.78) at an ultrahigh strain of 1,000%, a fast response time and linear correlation of ln(R/R0) and ln(L/L0) up to 1,000% strain. Most significantly, these sensors possess highmechanical strength (~0.6 MPa) and superb durability (>1,000 cycles at strain of 100%), stemming from the effective energy dissipation mechanism of the first agar network acting as sacrificial bonds and the CNFs serving as dynamic nanofillers. The combination of highstrain sensitivity and ultrahigh stretchability of hydrogel sensors makes it possible to sense both small mechanical deformations induced by human motions and large strain up to 1,000%. 相似文献
Complexes containing odd-electron Be−Be bonds are still rare until now. Hereby, a series of neutral di-beryllium amidinate complexes containing a Be−Be bond were explored theoretically. The complexes with direct chelation with the Be2 dimer by the bidentate amidinate (AMD) ligands are always corresponding to their global minimum structures. The detailed bonding analyses reveal that the localized electrons of the Be−Be fragment can be adjusted by the amount of AMD ligands because each AMD ligand only takes one electron from the Be2 fragment. Meanwhile, the hybridization of the central Be atom also changes as the number of AMD ligands increases. In particular, the sp3-hybridized single-electron Be−Be bond is firstly identified in the tri-AMD-ligands-chelated neutral D3h- Be2(AMD)3 complex, which also possesses the higher stability compared to its monoanionic D3h- Be2(AMD)3 − and monocationic C3- Be2(AMD)3 + analogues. Importantly, our study provides a new approach to obtain a neutral odd-electron Be−Be bond, namely by the use of radical ligands through side-on chelation. 相似文献
Journal of Cluster Science - A simple and environment-friendly autocatalytic reduction process was developed for synthesis of Au/Ni(OH)2 nanocomposites. The nanocomposites were characterized by... 相似文献
Two new cytochalasans flavichalasine N (1), flavichalasine O (2), together with six known cytochalasans (3–8), were isolated from Aspergillus flavipes PJ03-11 through the application of OSMAC (one strain many compounds) strategy. Flavichalasine O (2) represented the first example of cytochalasans possessing a nitrogen-oxygen heterocycle at the macrocyclic ring part. Their structures were established on the base of extensive spectroscopic analysis. Compounds 1–4 exhibited significant cytotoxic activities against three human cancer cell lines (THP1, HL-60 and PC3) with IC50 values ranging from 3.00 to 15.10?μM. 相似文献
Bi2O3/BiFeO3 composite was successfully fabricated by a conventional sol–gel method and structural properties were characterized based on X-ray diffractometer, scanning electron microscope, transmission electron microscope, energy-dispersive X-ray analyzer, nitrogen adsorption–desorption measurement, and UV–visible diffuse reflectance spectroscopy. Bi2O3/BiFeO3 had a good absorption for visible light, which was benefit to photocatalytic activity. The highest degradation efficiency was obtained when the content of Bi2O3 in Bi2O3/BiFeO3 was 63.9%. Effect of experimental conditions was investigated, and the highest photocatalytic activity of Bi2O3/BiFeO3 was observed at photocatalyst dosage of 0.5 g/L, initial BPA concentration of 10 mg/L, and solution pH of 6.3. Bi2O3/BiFeO3 photocatalyst exhibited enhanced photocatalytic activity for BPA, and the reaction rate constant over Bi2O3/BiFeO3 composite was 2.23, 3.65, and 8.71 times higher than that of BiFeO3, Bi2O3 and commercial TiO2 (P25), respectively. Bi2O3/BiFeO3 showed high photocatalytic activity after three cycles, suggesting that it was a stable photocatalyst. The possible photocatalytic mechanism has been discussed on the basis of the theoretical calculation and the experimental results. The hydroxyl and superoxide radicals together with photogenerated holes played significant roles in the photocatalytic reaction. 相似文献
A screening strategy involving designed extractors and collectors was used for the nondestructive quantitation of gangliosides on cell surfaces. The extractors were constructed by functionalizing maleimide silica bubbles with a DNA probe, which contains an endonuclease cleavage site and a boronic acid end to extract cell‐surface sialic acid‐containing compounds through simple centrifugation. After the extractors containing the extracted compounds were incubated with endonuclease, the released oligonucleotide‐gangliosides were selectively collected by silanized collector bubbles through hydrophobic interactions. The in vitro fluorescent signals from the collectors were used for the quantitation of cell‐surface gangliosides. By combining with sialidase cleavage, a protocol for the identification of ganglioside subtypes was developed. The successful monitoring of the regeneration of cell‐surface gangliosides demonstrates the potential of this strategy in probing related biological processes. 相似文献
A simple, sensitive and interference-free method was proposed for the determination of arsenic, based on the generation of volatile arsenic trichloride coupled with atomic fluorescence spectrometry. Thiourea, together with l-ascorbic acid, was used to reduce As(V) to As(III), and the chloride generation was based on the reaction between As(III) and hydrochloric acid. Under the optimized experimental conditions, the present procedure allows for the quantification of arsenic in the concentration range of 0.01–4.0 mg L−1, with a limit of detection (3σ) of 6.0 μg L−1. The relative standard deviation (R.S.D.) is 4.0% for 0.1 mg L−1 arsenic (n = 7). Finally, the proposed method was successfully applied to the determination of arsenic in several certified reference samples (stainless steel, alloy steel, copper alloy and water sample) and real samples (brass material and spiked cobalt material), with analytical results well-agreed with those by ICP-MS. 相似文献
An integrated aero-cryogel (A-CG) monolith with hierarchical porous structure was developed by inter-crosslinking of cellulose nanofiber/polylactic acid nanocomposite aerogel and carboxymethyl cellulose (CMC) cryogel (CG). The photothermal nanoparticles-enriched CMC CG phase served as a sunlight absorbing layer, exhibiting a broadband sunlight absorption of 98%. Due to the large amount of weakly bounded water molecules, the swelled CMC CG possessed a lower evaporation enthalpy than that of pure water, which facilitates water evaporation, while the nanocomposite aerogel phase acted as an excellent thermal insulator and afforded highly efficient water transport channels. Thus, the developed A-CG monolith supported by insulated polystyrene foam to protrude above the water surface, could reach an evaporation rate of 2.16 kg m?2 h?1 under an irradiation of 1 Sun (100 mw/cm2) with an efficiency of 93.6%. More remarkably, when the wind energy was imparted, an evaporation rate of 5.67 kg m?2 h?1 was achieved at a wind speed of 3 m s?1. The high-efficiency purification outcomes of various raw water demonstrate the great potentials of A-CG material in solar vapor generation.