Search

In this work, a novel sustained released system (VCSB-Zn(II)) for zinc supplements was built by vanillin-chitosan Schiff base (VCSB) chelated with Zn2+ to improve the zinc trace element utilization ratio. Samples were characterized by FT-IR, 1H NMR, XRD, SEM, and TGA. The results showed that VCSB exhibited a more excellent chelation capacity of Zn2+ than chitosan. The chelation capacity of VCSB was about 1.7 times more than that of chitosan, corresponding to 50.96 mg/g and 29.91 mg/g, respectively. Furthermore, VCSB-Zn(II) showed excellent sustained released performance at simulated gastric fluid because of the acid slow-dissolving ability. And the higher the C N content of VCSB, the higher the cumulative release rate (Ri) of Zn2+, the highest Ri reached 77.81%. The sustained released curves were described by the first-order and Korsmeyer-Peppas equation, which described the Zn2+ sustained released performance caused by the dissolution of VCSB-Zn(II) and Fick diffusion. This Zn2+ sustained released system shows great potential in the application in the field of trace elements supplements for animals.

“Real-life” metals inevitably form the oxide layer, thus leading to complex initial hydriding processes, which are still unclear because of the experimental challenges in monitoring elemental steps...

A series of calibration measurements have been performed on Suanni – the first small-angle neutron scattering spectrometer entering into routine user operation in China – aiming to characterize instrument performance and to provide a reference for user experiments. Various calibration standards were used to verify the precise association of the scattering intensity I with the scattering vector magnitude q at short and medium sample–detector distances. The measurements recorded for silver behenate powder revealed a slight shift of the neutron wavelength (λ) at the sample position as compared to the nominal λ calculated by the selector constant. The deviation was more significant with λ > 0.8 nm owing to the shape of the incoming neutron spectrum incident on the selector. The measured dead time for the entire detection system is 2.7 µs, as determined by measurements with varying fluxes. A protonated/deuterated polystyrene blend was employed as the primary standard to calibrate the secondary standard H2O. The instrument covers an effective q range between 0.013 and 5 nm−1, as demonstrated by scattering curves obtained from a monodisperse poly(methyl methacrylate) nanoparticle suspension and a glassy carbon plate.

The mechanical properties and the hierarchical filler structures were characterized on a series silica-filled silicone rubber with a filler fraction (ΦSi) varied from 0.05 phr to 80 phr (parts per hundred rubber). Uniaxial elongation measurement suggests that there is a percolation threshold between 10 and 30 phr. Moreover, an optimum ΦSi range from 40 phr to 50 phr is found, in which the best mechanical performances of reinforcement are shown. The microscopic structures were crosschecked by small-angle neutron scattering (SANS) and scanning electron microscopy (SEM). The effects of the ΦSi and the fabrication process on the morphology of samples are unveiled. The correlation length among aggregates extracted from SANS data monotonically decrease from 237.0 nm to 136.5 nm with increasing the ΦSi from 30 phr to 80 phr. The average radius of gyration of aggregates 〈Rg,agg〉 fitted with the Beaucage model monotonically decrease from 49.2 nm to 37.5 nm with increasing ΦSi from 10 phr to 80 phr. Providing a 10 nm thickness bound rubber as bridge, samples with optimum ΦSi yield a morphology that the radii of aggregates and the gap filled with polymer matrix in between are equivalent as both around 60 nm.

Mechanically flexible supercapacitors with fast charge-discharge capacity, high stability and good mechanical properties are essential for powering flexible electronics devices. In this paper, we report a simple process to obtain composite electrode consisting of graphene and polyaniline on stainless steel fabric. The all solid-state flexible supercapacitors based on the composite electrode exhibit a maximal specific capacitance of 1506.6 mF/cm2, and capacitance retention of 92% after 5000 charge-discharge cycles. Furthermore, the bending test shows that the flexible supercapacitor maintains 95.8% of the original capacitance after 1000 bending cycles. The high capacitive performance and anti-bending property of the supercapacitor are ascribed to the favourable microstructure of graphene/polyaniline composite and high flexibility of stainless steel fabric. Our work demonstrates a novel type of high-performance flexible electrode, which will boost the development of flexible and wearable electronics and integrated fabric power devices.

In this paper, an electropositive adsorbent, salicylaldehyde-chitosan Schiff base (SCSB), was prepared via chitosan modification. The results showed that SCSB exhibited electrostatic adsorption on anionic dyes with a better adsorption performance than chitosan, corresponding to 24.75% and 79.80% removal rate of methyl orange (MO), respectively. Furthermore, the positive charge from the C = N was not strong enough to counter the electron-donating effect of salicylaldehyde, the MO removal rates of 0.5SCSB, 1.0SCSB, and 1.5SCSB were 79.80%, 69.02% and 59.60%, respectively. In the pH test, the imine group (C = N) hydrolysis showed a greater impact on charges changing than the amino group (–NH2) hydrolysis.

A new pinhole small-angle neutron scattering (SANS) spectrometer, installed at the cold neutron source of the 20 MW China Mianyang Research Reactor (CMRR) in the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, has been put into use since 2014. The spectrometer is equipped with a multi-blade mechanical velocity selector, a multi-beam collimation system, and a two-dimensional He-3 position sensitive neutron detector. The q -range of the spectrometer covers from 0.01 nm −1 to 5.0 nm −1 . In this paper, the design and characteristics of the SANS spectrometer are described. The q -resolution calculations, together with calibration measurements of silver behenate and a dispersion of nearly monodisperse poly-methyl-methacrylate nanoparticles indicate that our SANS spectrometer has a good performance and is now in routine service.

Cr/W multilayer nanocomposites were presented in the paper as potential candidate materials for the plasma facing components in fusion reactors. We used neutron reflectometry to measure the depth profile of helium in the multienergy He ions irradiated [Cr/W (50 nm)]3 multilayers. Results showed that He-rich layers with low neutron scattering potential energy form at the Cr/W interfaces, which is in great agreement with previous modeling results of other multilayers. This phenomenon provided a strong evidence for the He trapping effects of Cr/W interfaces and implied the possibility of using the Cr/W multilayer nanocomposites as great He-tolerant plasma facing materials.

Helium status is the primary effect of material properties under radiation.10B-doped aluminum samples were prepared via arc melting technique and rapidly cooled with liquid nitrogen to increase the boron concentration during the formation of compounds. An accumulated helium concentration of ~6.2 × 1025 m−3was obtained via reactor neutron irradiation with the reaction of10B(n,α)7Li. Temperature-stimulated helium evolution was observed via small-angle X-ray scattering (SAXS) and was confirmed via transmission electron microscopy (TEM). The SAXS results show that the volume fraction of helium bubbles significantly increased with temperature. The amount of helium bubbles reached its maximum at 600°C, and the most probable diameter of the helium bubbles increased with temperature until 14.6 nm at 700°C. A similar size distribution of helium bubbles was obtained via TEM after in situ SAXS measurement at 700°C, except that the most probable diameter was 3.9 nm smaller.