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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...

Objectives This work aims to exploring the risk factors related to ECC by investigating oral health status, related behaviours and habits of children and their parent's knowledge regarding oral hygiene. Method A total of 2700 children aged 3-5 years and their parents from Zhejiang province were examined. Chi-square test or U test was used to analyse the difference of caries incidence among different groups. Logistic multiple factor stepwise regression model was used to analyse the risk factors influencing ECC prevalence. Results ECC prevalence rate in these children was 70.7%. The mean decayed missing filled teeth(dmft) scores were 4.33. Through analysis of logistic multiple factor stepwise regression model, risk factors related to the prevalence of ECC in children include: older age, region (coastal or mountainous area), higher frequency of bedtime dessert consumption and poor care of children's oral health by parents. In the questionnaire, 5 of 14 questions showed parents' poor oral knowledge or awareness. Conclusion The prevalence rate of ECC in children aged 3-5 in this study was high and associated with older age, region (coastal or mountainous area), higher frequency of bedtime dessert consumption and poor care of children's oral health. Parents need to strengthen their understanding and action of dental caries.

In this work, a novel sustained released system (VCSB-Zn(II)) for zinc supplements was built by vanillin-chitosan Schiff base (VCSB) chelated with Zn

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.

Molecular dynamics (MD) simulation was conducted to research the effect of molar ratios for α/β-HMX, γ/β-HMX, and δ/β-HMX(octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine) mixture systems on thermal stability, sensitivity, and mechanical properties of explosives, and the computing models were established by Materials Studio (MS). The binding energies, the maximum trigger bond length (LN–NO2), cohesive energy density as well as mechanical properties of the mixture systems and the pure β-HMX crystal were obtained and contrasted. The results demonstrate that the molar ratios have great influence on the binding capacity of molecules between α, γ, δ-HMX, and β-HMX in the mixture systems. The binding energies decrease with the increase of molecular molar ratio and have the maximum values at the 1:1 M ratio. The maximum trigger bond length does not change apparently after mixing, while the cohesive energy density (CED) increases as the molar ratio increases but are all smaller than the pure β-HMX crystal, demonstrating that the sensitivity of the mixture systems increases. The mechanical properties decrease after mixture, which illustrates that the mechanical properties of the pure crystal are superior to the mixture systems.

TiAIN, CrAIN films and alternate CrAIN/TiAIN multilayers with different repeated bilayer thickness ranging from 10 to 30 nm were prepared by reactive magnetron sputtering. The interface structures of the films were characterized using x-ray reflectometry method. The individual thickness of the repeated bilayers in multilayers and total thickness of the films are close to the nominal thickness and they are more accurate for thicker films. The interface roughness increases as the thickness of the repeated bilayer in mutilayers decreases. The scattering length density profiles of the films suggests that the chemical composition is more accurate for thicker films.

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.

A new cold neutron triple axis spectrometer named Kunpeng at the China Mianyang Research Reactor (CMRR), Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics has been constructed and fully tested. It can be typically used to study magnetic excitations, spin and lattice dynamics in condensed matter physics. In this contribution we present its main features and the first experimental data to demonstrate its performance.

Many new instruments at China Spallation Neutron Source (CSNS) require 3He-free neutron detectors with high counting rate capability to match the high neutron flux provided. The GEM(Gas Electron Multiplier)-based neutron detector is one of few detectors that can operate under direct irradiation from a neutron beam. A prototype detector was constructed using 10 GEM foils of 200 mm × 200 mm. To improve the detection efficiency, eight of the GEM foils and two cathodes were coated with enriched boron (96% 10B). To investigate its basic characteristics, several neutron beam tests were carried out at CSNS and the China Mianyang Research Reactor (CMRR). The spatial resolution of the GEM-based neutron detector was below 2.94 ± 0.01 mm (FWHM). Using monoenergetic neutrons at a wavelength of 4.9 A, the detection efficiency was 54 ± 2%, consistent with the efficiency of 52% given by a Geant4 simulation. The wavelength spectrum measured with this detector using the TOF(Time Of Flight) approach at CSNS agreed well with that measured using a 3He tube. The results show that the GEM-based neutron detector is an ideal candidate to measure the direct neutron beam. Its overall detection efficiency is close to that of conventional 3He neutron detectors.

Evolution and change of He bubbles in magnetron sputtering prepared He-containing Ti films under thermal treatment are studied by small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and X-ray diffraction. Incorporation of He introduces a large number of He-vacancy clusters and some voids in the films, and significantly increases SAXS intensity and causes anisotropic scattering. The change of He induced defects during annealing is affected by thermal diffusion and migration of trapped He to the surface and between interfaces of He induced defects within the films. Annealing at 200 and 400 degrees C reduces intensity and anisotropy of SAXS, in accord with observed shrinking and disappearance of the voids. The simultaneous growth of non-uniformly distributed He bubbles to the sizes of 1-2 nm and a population level of 10(5)/mu m(3) are detected in the temperature range. The changes are explained by migration and coalescence mechanisms, which requires low apparent activation energy. Inconsistence between TEM and SAXS observations is noted and attributed to thinning induced internal stress relaxation of TEM specimen. Remarkable enlargement of He bubbles, associated with increased SAXS intensity and fractal dimension, is observed after 600 degrees C annealing, indicating involvement of Ostwald Ripening (OR) mechanism. The OR process dominates at 800 degrees C, where the high temperature provides activation energy for accelerated He dissociation from small bubbles into larger ones, and generating textured microstructure and agglomerated bubble clusters. The inhomogeneous bubble size distribution observed at this temperature covers a broad range of about 10-50 nm and possessing a population density level of 10(3)/mu m(3). (C) 2014 Elsevier B.V. All rights reserved.

Tensile stress–strain relationship of a rolled Zircaloy-4 (Zr-4) plate was examined in situ using a neutron diffraction method at room temperature (RT, 25 C) and an elevated temperature (250 C). Variations of lattice strains were obtained as a function of macroscopic bulk strains along prismatic (1 0 1 0), basal (0 0 0 2) and pyramidal (1 0 1 1) planes in the hexagonal close-packed structure of the Zr-4. The mechanisms of strain responses in these three major planes were simulated using elastic–plastic self-consistent (EPSC) model based on Hill–Hutchinson method, thus the inter-granular stresses and deformation systems of each individual grain under loading were obtained. Results show that there is a good agreement between the EPSC modeling and neutron diffraction measurements in terms of macroscopic stress–strain relationship and lattice strain evolutions of the planes at RT. However, there is a slight discrepancy in the lattice strains obtained from the EPSC modeling and neutron diffraction when the specimen was deformed at 250 C. Analysis of grain structure and texture obtained using electron back-scattered diffraction suggests that dynamic recovery process is significant during the tensile deformation at the elevated temperature, which was not considered in the simulation.

A new time-of-flight neutron reflectometer with a polarization option is developed and tested at the Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, China. Its scattering geometry is horizontal. The constructed neutron reflectometer is a multipurpose instrument that can be used for the characterization of a stratified microstructure and hidden interfaces of solid thin films. Diting is designed for both magnetic and nonmagnetic multi-layer thin films. Spin polarization and analysis are achieved by transmission magnetized supermirrors. The sample unit is equipped with an electromagnet, which can provide a vertical magnetic field range of 0-1.2 tesla. The available neutron beam is a white beam with wavelength range of 0.15-1.25 nm, which can be cut into different wavelength resolution neutron pulses by a four-disk chopper. A two-dimensional position-sensitive detector is employed to count the specular and off-specular reflected neutron beam. A minimum reflectivity of 10-6 is measured on this instrument.

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.

Flexible solid-state supercapacitors attract more and more attention as the power supply for wearable electronics. To fabricate such devices, the flexible and economical current collectors are needed. In this paper, we report the stainless steel fabrics as the current collector for high-performance graphene-based supercapacitors. The stainless steel fabrics have superior properties compared with the widely used flexible current collectors. The flexible supercapacitors show large specific capacitance of 180.4 mF/cm(2), and capacitance retention of 96.8% after 7500 charge-discharge cycles. Furthermore, 96.4% of the capacitance is retained after 800 repeating stretching-bending cycles. The high performance is related to the excellent conductivity, good mechanical flexibility, and high electrochemical stability of the stainless steel fabrics. The achievement of such high-performance and flexible supercapacitor can open up exciting opportunities for wearable electronics and energy storage applications.

The small-angle neutron scattering spectrometer, SANS-Suanni, of the 20 MW China Mianyang Research Reactor (CMRR), was upgraded recently to improve its performance and anti-risk capability. The major modifications include: (i) installing a new mechanical velocity selector consisting of a rotor with helical slots; (ii) a replacement of the front of the detector tank to decrease the minimum sample-to-detector distance; (iii) installing a laser locator and a set of fixed lenses in collimator chamber. After the modifications, firstly, a higher maximum-q (qmax) can be achieved up to 6.3 nm−1. With the help of rotating the detector tank, qmax can be further increased to 10.5 nm−1. Secondly, a higher neutron flux at sample position up to 1.18 ×107 cm−2s−1 (at neutron wavelength of 0.53 nm) is obtained. Thirdly, a convenient and user-friendly beam center finding operation for environmental devices is available. The actual performance after the modifications is demonstrated with the measurements of standard samples.

The high resolution neutron diffractometer HRND is located at the 20 MW China Mianyang Research Reactor (CMRR), which is a neutron powder diffractometer especially dedicated to crystal and magnetic structure studies for polycrystalline powder samples. A vertical focusing Ge (511) monochromator produce a monochromatic neutron beam with a wavelength of 1.885 A at a fixed take-off angle of 120o. An array of 64 equidistant 3He filled proportional counters can acquire diffraction patterns with a large-scale diffraction angle range over 160o. As all the Soller slit collimators of HRND have a collimation angle of 10' and the monochromator has an average mosaicity of 0.359o, HRND obtains a best resolution of about 1.6\textperthousand based on experiments, which makes the resolution of HRND can compete with the mainstream-level high resolution neutron powder diffractometers in the world. Equipped with a cryostat and a furnace, HRND allows structural characterization in an extremely broad temperature range. The details of the configuration and performance of the instrument are reported along with its specifications and performance assessments in the present paper.

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.