The impact of a liquid droplet with another droplet or onto a solid surface are important basic processes that occur in many applications such as agricultural sprays and inkjet printing, and in nature such as pathogens transport by raindrops. We investigated the head-on collision of unequal-size droplets of the same liquid on wetting surfaces using the direct numerical simulations technique at different size ratios. The unsteady Navier–Stokes equations are solved and the liquid–gas interface is tracked using the geometric volume-of-fluid method. The numerical model is validated by comparing simulation results of two extreme cases of droplets bouncing with the experimental data from previous studies and the agreement is quite accurate. The validated model is employed to simulate droplets bouncing at several size ratios at different Weber numbers and Ohnesorge number. Two distinct regimes are identified, namely, the inertial regime, where the restitution coefficient is a constant value close to 0.3, the viscous regime, where the restitution coefficient declines. To understand the bouncing behaviour, the velocity field is analysed and an energy budget calculation is performed. The distribution of the sessile droplet energy is found to be important and the sessile droplet surface energy is calculated by its deformation characteristics such as crater depth. Finally, a scaling analysis is performed to rationalize the insensitivity of the coefficient of restitution in the inertial regime, and its decline in the viscous regime, at large size ratios.

Effects of solid nanolayers embedded in a near-critical density plasma on the laser-driven collisionless shock acceleration are investigated by using two-dimensional particle-in-cell simulations. Due to the interaction of nanolayers and the incident laser, an additional number of hot electrons are generated and an inhomogeneous magnetic field is induced. As a result, the collisionless shock is reinforced within the nanolayer gaps compared to the target without the structured nanolayers. When the laser intensity is 9.8 × 1019 W/cm2, the amplitude of the electrostatic field is increased by 30% and the shock velocity is increased from 0.079c to 0.091c, leading to an enhancement of the peak energy and the cutoff energy of accelerated protons, from 6.9 MeV to 9.1 MeV and 12.2 MeV to 20.0 MeV, respectively. Furthermore, the effects of the width of the nanolayer gaps are studied, by adjusting the gap width of nanolayers, and optimal nanolayer setups for collisionless shock acceleration can be acquired.

The effects of magnetic vortex acceleration (MVA) are investigated with two-dimensional particle-in-cell (PIC) simulations by laser interaction with near-critical density (NCD) plasma inside a hollow conical plasma. Energetic and collimated proton beams can be accelerated by a longitudinal charge-separation field. Energetic protons with a peak energy of 220 MeV are produced in PIC simulations. Compared with a uniform NCD plasma, both the cutoff energy and collimation of proton beams are improved remarkably. Furthermore, the influence of different gap sizes of cone tip is taken into account. For optimizing magnetic vortex acceleration, the gap size of the cone tip is suggested to match the focal spot size of laser pulse.

Zearalenone (ZEA), a common contaminant in food and feedstuffs, threatens human and animal health. The present study aimed to investigate the protective effects of modified palygorskite (MPal), a ZEA-targeted adsorbent, on broilers (young chickens) fed a ZEA-contaminated diet. Broilers were subjected to one of three treatments for a period of 42 days: a basal diet (control group), a ZEA- contaminated diet, and a ZEA-contaminated diet supplemented with 1 g/kg of MPal. Blood was collected for serum metabolite assay, and liver and kidney were sampled to determine ZEA residue and antioxidant-related parameters, using commercial spectrophotometric kits. Compared with the basal diet, the ZEA- contaminated diet resulted in compromised growth performance (reduced daily gain and feed intake during finisher period), disordered relative liver weight (decreased at 21 days but increased at 42 days), increased ZEA residue in liver and kidney, abnormal serum metabolites (decreased total protein content but increased alanine aminotransferase activity at 21 and 42 days, reduced albumin content at 21 days, and elevated aspartate aminotransferase activity at 42 days), and disrupted antioxidant capacities of broilers (increased total superoxide dismutase (T-SOD) activity in liver at 21 and 42 days, decreased T-SOD activity in kidney at 21 and 42 days, and in serum at 42 days, greater malondialdehyde accumulation in liver and kidney at 42 days, and lower glutathione content in kidney at 21 days). The adverse consequences resulting from the ZEA-contaminated diet were relieved by the supplementation of MPal (except albumin concentration in serum and T-SOD activity in liver at 21 days), with the values of growth-performance parameters, liver weight, renal ZEA accumulation, total protein content, transaminase activity at 42 days, and antioxidant indexes being similar to those in the control group. These results suggested that MPal supplementation could promote growth performance, attenuate liver damage, and improve the antioxidant abilities of broilers fed ZEA-contaminated diet by reducing ZEA accumulation.

A novel curved surface nanowire target is proposed to improve the cutoff energy of accelerated protons via target normal sheath acceleration. The interaction of a laser of intensity $1.37\times 10^{20}\ {\rm W}\ {\rm cm}^{-2}$ with a curved surface nanowire target is studied by two-dimensional particle-in-cell simulations. The numerical results indicate that the sheath electric field at the target rear side is significantly enhanced by this simple target design, compared with using the planar nanowire target. The transverse motion of hot electrons is effectively confined and the energy density of electrons is naturally increased. A series of simulations with various target parameters is carried out to investigate the performance of this novel target. This tailored target may provide implications for generating high-quality proton beams in experiments.

Interactions between the boundary layer and two successive incident shock waves (ISWs) often occur in the supersonic mixed-compression inlets. However, the flow mechanism involved in such interactions has been studied rarely. In this study, we investigate experimentally and analytically the turbulent boundary layer separation flow induced by the single ISW and dual ISWs at the identical total deflection angles in a Mach 2.73 flow. Schlieren photography, wall pressure measurement and surface oil-flow visualisation are employed to diagnose the flow field. Experiments with the impingement points of the two ISWs intersecting on the bottom wall exhibit a separated flow with a triangle-like separation bubble, namely the first kind of dual-ISW/turbulent boundary layer interaction (ISWTBLI). Comparative studies show that various flow features of this kind of dual-ISWTBLI, including the extent of the separation region, pressure distribution and surface-flow topological structures, are nearly identical to those of the single-ISWTBLI with an identical total deflection angle. As the distance between the two ISWs increases, the shape of the separation region in the dual-ISWTBLI changes from triangle-like to quadrilateral-like, and the height of the separation region decreases accordingly, forming the second kind of dual-ISWTBLI. Furthermore, an inviscid model is developed for the dual-ISWTBLI to describe the complex shock wave system and elucidate the cause of a quadrilateral-like separation bubble in the second kind of dual-ISWTBLI. Moreover, based on a previous work by Souverein et al. (J. Fluid Mech., vol. 714, 2013, pp. 505–535) on the single-ISWTBLI, a modified scaling method is established for the first kind of dual-ISWTBLI.

The single initial Global Positioning System (GPS) has been expanded into multiple global and regional navigation satellite systems (multi-GNSS/RNSS) as the Global Navigation Satellite System (GLONASS) is restored and the BeiDou Navigation Satellite System (BDS), Galileo Satellite Navigation System (Galileo) and Quasi-Zenith Satellite System (QZSS) evolve. Using the differences among these five systems, the paper constructs a consolidated multi-GNSS/RNSS precise point positioning (PPP) observation model. A large number of datasets from Multi-GNSS Experiment (MGEX) stations are employed to evaluate the PPP performance of multi-GNSS/RNSS. The paper draws three main conclusions based on the experimental results. (1) The combined GPS/GLONASS/Galileo/BDS/QZSS presents the PPP with the shortest mean convergence time of 11·5 min, followed by that of GPS/GLONASS/Galileo/BDS (12·4 min). (2) The combined GPS/GLONASS/BDS/Galileo/QZSS shows the optimal PPP performance when the cut-off elevation angle is basically the same because of the rich observation data due to a large number of satellites. To be specific, for combined GPS/GLONASS/BDS/Galileo/QZSS, the PPP convergence percentage is 80·9% higher relative to other combined systems under 35° cut-off elevation angle, and the percentages of the root mean square values of PPP within 0–5 cm are enhanced by 80·5%, 81·5% and 87·3% in the North, East and Up directions relative to GPS alone at 35° cut-off elevation angle. (3) GPS alone fails to conduct continuous positioning due to the insufficiency of visible satellites at 40° cut-off elevation angle, while the kinematic PPP of multi-GNSS/RNSS remains capable of obtaining positioning solutions with relatively high accuracy, especially in the horizontal direction.

The effect of maternal folate intake on small-for-gestational-age (SGA) births remains inconclusive. The present study aimed to investigate the associations of maternal folate intake from diet and supplements with the risk of SGA births using data from a cross-sectional study in Shaanxi Province of Northwest China. A total of 7307 women who were within 12 months (median 3; 10th–90th percentile 0–7) after delivery were included. Two-level models were adopted to examine the associations of folate (dietary folate, supplemental folic acid and total folate) intake with the risk of SGA births and birth weight Z score, controlling for a minimum set of confounders that were identified in a directed acyclic graph. Results showed that a higher supplemental folic acid intake during the first trimester was negatively associated with the risk of SGA births (≤60 d v. non-use: OR 0·80; 95 % CI 0·66, 0·96; >60 d v. non-use: OR 0·78; 95 % CI 0·65, 0·94; Ptrend = 0·010; per 10-d increase: OR 0·97; 95 % CI 0·95, 0·99). A higher total folate intake during pregnancy was associated with a reduced risk of SGA births (highest tertile v. lowest tertile: OR 0·77; 95 % CI 0·64, 0·94; Ptrend = 0·010; per one-unit increase in the log-transformed value: OR 0·81; 95 % CI 0·69, 0·95). A similar pattern was observed for the birth weight Z score. Our study suggested that folic acid supplementation during the first trimester and a higher total folate intake during pregnancy were associated with a reduced risk of SGA births.

Underground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors were commissioned. JUNA plans to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. At the first period, JUNA aims at the direct measurements of 25Mg(p,γ)26 Al, 19F(p,α) 16 O, 13C(α, n) 16O and 12C(α,γ) 16O near the Gamow window. The current progress of JUNA will be given.

Monosized spherical Cu–20% Sn (wt%) alloy particles with diameter ranging from 70.6 to 334.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). Fully dense without pores and bulk inclusions, the cross-sectional micrographs of the spherical alloy particles indicate an even distribution of Cu and Sn. These spherical Cu–Sn alloy particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid Cu–Sn alloy can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the cooling rate of spherical Cu–20% Sn alloy particles is estimated by a Newton’s cooling model. The cooling rate of the Cu–20% Sn alloy particle decreases gradually with the particle diameter increasing. Smaller particles have higher cooling rates and when the particle diameter is less than 70 μm, the cooling rate of particles can reach more than 3.3 × 104 K/s. The secondary dendrite arm spacing has strong dependence on particle diameter which increases gradually with the increase of particle diameter. The results demonstrate that POEM is an effective route for fabrication of high-quality monosized Cu–20% Sn alloy particles.

This study was conducted to investigate the protective effects of l-threonine (l-Thr) supplementation on growth performance, inflammatory responses and intestinal barrier function of young broilers challenged with lipopolysaccharide (LPS). A total of 144 1-d-old male chicks were allocated to one of three treatments: non-challenged broilers fed a basal diet (control group), LPS-challenged broilers fed a basal diet without l-Thr supplementation and LPS-challenged broilers fed a basal diet supplemented with 3·0 g/kg l-Thr. LPS challenge was performed intraperitoneally at 17, 19 and 21 d of age, whereas the control group received physiological saline injection. Compared with the control group, LPS challenge impaired growth performance of broilers, and l-Thr administration reversed LPS-induced increase in feed/gain ratio. LPS challenge elevated blood cell counts related to inflammation, and pro-inflammatory cytokine concentrations in serum (IL-1β and TNF-α), spleen (IL-1β and TNF-α) and intestinal mucosa (jejunal interferon-γ (IFN-γ) and ileal IL-1β). The concentrations of intestinal cytokines in LPS-challenged broilers were reduced by l-Thr supplementation. LPS administration increased circulating d-lactic acid concentration, whereas it reduced villus height, the ratio between villus height and crypt depth and goblet density in both jejunum and ileum. LPS-induced decreases in jejunal villus height, intestinal villus height:crypt depth ratio and ileal goblet cell density were reversed with l-Thr supplementation. Similarly, LPS-induced alterations in the intestinal mRNA abundances of genes related to intestinal inflammation and barrier function (jejunal toll-like receptor 4, IFN-γ and claudin-3, and ileal IL-1β and zonula occludens-1) were normalised with l-Thr administration. It can be concluded that l-Thr supplementation could attenuate LPS-induced inflammatory responses and intestinal barrier damage of young broilers.

There has been a continuous call for active, durable, and low-cost catalysts for a range of catalysis reactions. In this paper, porous Co@C composed of uniformly dispersed Co metal nanoparticles in hexagonal-shaped prisms carbon matrix were fabricated by in situ pyrolysis of hexagonal-shaped prismatic Co-MOF-74 crystals. The obtained nanoporous carbons have a high surface area of 195.2 m2/g and a strong magnetic response, thereby realizing fast molecular diffusion of reactant and easy magnetic separation. The resulting Co@C catalyst show a superior and durable catalytic activity for reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). Moreover, Co@C can be recycled and still retains more than 75% of its original catalytic activity after 6 cycles. Therefore, it is reasonable to believe that such Co@C nanocomposites have great potential as a highly efficient and low-cost heterogeneous catalyst. It is believed that MOFs can be used to produce other catalysts with high porosity and uniformly dispersed active sites.

The effect of a parallel viscous force induced damping and the magnetic precessional drift resonance induced damping on the stability of the resistive wall mode (RWM) is numerically investigated for one of the advanced steady-state scenarios in international thermonuclear experimental reactor (ITER). The key element of the investigation is to study how different plasma rotation profiles affect the stability prediction. The single-fluid, toroidal magnetohydrodynamic (MHD) code MARS-F (Liu et al., Phys. Plasmas, vol. 7, 2000, p. 3681) and the MHD–kinetic hybrid code MARS-K (Liu et al., Phys. Plasmas, vol. 15, 2008, 112503) are used for this purpose. Three extreme rotation profiles are considered: (a) a uniform profile with no shear, (b) a profile with negative flow shear at the $q=2$ rational surface ( $q$ is the equilibrium safety factor), and (c) a profile with positive shear at $q=2$ . The parallel viscous force is found to be effective for the mode stabilization at high plasma flow speed (about a few percent of the Alfven speed) for the no shear flow profile and the negative shear flow profile, but the stable domain does not appear with the positive shear flow profile. The predicted eigenmode structure is different with different rotation profiles. With a self-consistent inclusion of the magnetic precession drift resonance of thermal particles in MARS-K computations, a lower critical flow speed, i.e. the minimum speed needed for full suppression of the mode, is obtained. Likewise the eigenmode structure is also modified by different rotation profiles in the kinetic results.

In this paper, we are devoted to nonlinear stability and B-convergence of additive Runge-Kutta (ARK) methods for nonlinear stiff problems with multiple stiffness. The concept of -algebraic stability of ARK methods for a class of stiff problems Kστ is introduced, and it is proven that this stability implies some contractive properties of the ARK methods. Some results on optimal B-convergence of ARK methods for Kσ,0 are given. These new results extend the existing ones of RK methods and ARK methods in the references. Numerical examples test the correctness of our theoretical analysis.