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Simulating the comprehensive functions of native skin—and not simply the perception of external physical stimuli—by electronic skin (e-skin) has gathered increasing attention in the development of wearable devices and human-interactive technology. Here, we report an anti-bacterial, color-variable, ultraviolet (UV)-sensitive, shape-adaptive, and immunoregulatory e-skin based on a single- and dual-network switchable hydrogel composed of a covalent network of polyacrylamide (PAAm) and a coordinated network of xanthan gum (Xg)/iron ions [Fe(III)]. In the presence of sodium lactate and UV exposure, Fe(III) could be reduced to Fe(II), which de-coordinated the Xg/Fe(III) network. During this reduction process, the e-skin realized three functions of real skin: (i) UV triggered a color change with detectable resistance alterations; (ii) reactive oxygen species (ROS) were dramatically produced to defend against pathogens; and (iii) the piezoresistant hydrogel became highly stretchable to perceive all-scale human motions. Moreover, the shear-thinning properties of Xg in the precursor solution allowed the e-skin to be printable, and the anti-inflammatory functions of de-coordinated Xg were beneficial for wound healing. In summary, this newly-developed e-skin can achieve the perception of UV and human motions. It has promising applications for irregularly-shaped body surfaces and infected wounds.

In order to break through the limitations of wood solar drying and its application in the tropics, the core part of a wood solar drying system (collection/storage media) should be adapted to the se...

Nanostructured fluoridated hydroxyapatite (FHA) coatings were deposited on Ti substrates using the suspension plasma spraying (SPS) process. The effects of the plasma spraying power on the microstructure and properties of coatings were intensively studied. The X-ray diffraction pattern showed that the as-sprayed coatings mainly consisted of the hydroxyapatite (HA) phase, and the crystal size was estimated to be dozens of nanometers. With the increase of the spraying power, the amount of decomposed phases, crystallinity, and crystal size increased. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed the presence of fluorine in the as-sprayed coatings. The corrosion in simulated body fluid (SBF) was studied using potentiodynamic polarization tests, and the results indicated that the coating greatly enhanced the corrosion resistance of the Ti substrate. The chemical stability was assessed by measuring the weight loss of the coatings before and after immersion in a citric acid-modified phosphate buffered saline (PBS) solution at various intervals. The results showed that increasing the spraying powers decreased the dissolution rate of coatings. The in vitro bioactivity was characterized by soaking coatings in the SBF solution for different times, and the obtained results suggested that the spraying power levels affected the initial nucleation rate of the bone-like apatite on the coating surface. The antibacterial activity was investigated using optical density (OD) growth curves and colony-forming unit assays. The coating prepared at a low spraying power had relatively high antibacterial activity with respect to Staphylococcus aureus.

The Sm8Co73.2Fe8.8B10 ribbons were prepared by melt-spinning at a roller velocity of 40 m/s followed by annealing at 700–900 °C for 30 min, and then their structure and magnetic properties were studied. The results show that the as-spun ribbons are composed of Sm(Co,Fe)12B6 and Sm2(Co,Fe)14B nanocrystallines with an average size of ∼10 nm distributed on the amorphous matrix, and exhibit the weak hard magnetic properties. Moreover, the annealing treatment at 800 °C can obviously improve the ones, and make the ribbons consist of Sm(Co,Fe)12B6, Sm2(Co,Fe)14B, Sm2(Co,Fe)7, Co0.72Fe0.28 and a little residual amorphous phase. However, a higher annealing temperature of 900 °C will reduce the comprehensive magnetic properties of ribbons due to the changes in microstructure. The Curie temperatures of Sm(Co,Fe)12B6, Sm2(Co,Fe)14B, Co0.72Fe0.28 phases are -(103–120) °C, 770–780 °C and 900 °C, respectively. The relationship between microstructure and magnetic properties was discussed in detail and the microstructural model was proposed to determine the magnetic properties.

The SmCo3.1−xFe0.9CuxB (x = 0, 0.02, 0.06 and 0.1) ribbons were prepared by melt-spinning at 40 m/s accompanied by annealing at 800 °C for 30 min, and then their structures and magnetic properties were investigated. The results show that the annealed ribbons are composed of single Sm(Co,Fe)4B phase at x = 0, and single Sm(Co,Fe,Cu)4B phase at x = 0.02–0.1. These phases with different Cu contents have the same hexagonal CeCo4B-type structure with a space group of P6/mmm, and the lattice parameters a and c increase monotonically with increasing x from 0 to 0.1, while the axial ratio of c/a remains almost unchanged (c/a = 1.3495). In particular, the x = 0.06 ribbons consisting of short rod-shaped Sm(Co,Fe,Cu)4B grains, which contact with each other directly, show the high coercivity of up to 44450.0 Oe, and each in-plane grain exhibits preferred orientation along its long or short axis direction.

The phase compositions, atomic structures and magnetic properties of as-spun SmCo4B and SmCo3.1Fe0.9B ribbons are comparatively studied. It was found that SmCo4B and SmCo3.1Fe0.9B ribbons consist of single SmCo4B or Sm(Co,Fe)4B phase, respectively. The SmCo4B phase displays homogeneous equiaxed grains, which contact each other directly, while Sm(Co,Fe)4B phase does not expose its clear grain profile. The Extended X-ray Absorption Fine Structure (EXAFS) analysis shows that both interatomic distance and disorder degree increase when a part of Co is substituted by Fe in SmCo4B ribbons. Such change in atomic structure increases the effect of atomic mismatch and the glass-forming ability of SmCo4B ribbons, but reduces the magnetocrystalline anisotropy. Annealing is quite helpful to improve the magnetic properties of SmCo3.1Fe0.9B ribbons.

A new Sm(Co,Fe,Cu)4B/Sm2(Co,Fe,Cu)7 cell structure is found, and its phase composition, microstructure and magnetic properties are investigated. Particularly, the atom structure of main phase is analyzed by extended X-ray absorption fine structure. It was found that as-spun SmCo2.94FeCu0.06B ribbons were composed of amorphous phase and approximate equiaxed Sm(Co,Fe,Cu)4B nanocrystallines. The high disorder of the nanocrystallines leads to the low magnetic anisotropy. After the as-spun ribbons were annealed at 800 °C for 30 min, the amorphous phase disappeared completely. The short rod-shaped Sm(Co,Fe,Cu)4B grains have a staggered distribution accompanied by ∼8 vol% lamellar Sm2(Co,Fe,Cu)7 phase at grain boundaries, and the new cell/cell-wall-type Sm(Co,Fe,Cu)4B/Sm2(Co,Fe,Cu)7 microstructure is produced. The annealed ribbons show an ultra-high coercivity of up to 5.01 T at room temperature, 40.64 T at 5 K (obtained by extrapolating), and estimated to be ∼ 41.96 T at 0 K. The microstructureal models of both ribbons are created and the coercivity mechanism is discussed in detail.

Fe-24Cr-12Co-1.5Si ribbons were prepared by simple melt spinning and aging processes, and their microstructure and phase transition were studied. The average grain size of the aged ribbons is ∼4.22 μm, much smaller than that of traditional bulk Fe-Cr-Co alloy. The as-spun ribbons are mainly composed of BCC-type α and FCC-type Cr(M). During aging treatment, the Cr(M) phase firstly partly transforms into (CrSi) 0.99 (FeCo) 1.01 at the initially higher aging temperature, accompanied by the continuous spinodal decomposition of α→α 1 +α 2 , and at the lower aging temperature the residual Cr(M) and α turn into Fe(Si,M) 2 (M = Cr, Co) and Co 2 Si rather than (CrSi) 0.99 (FeCo) 1.01 . And a new uniform cellular microstructure is formed in the ribbons after multi-stage aging, in which the (Fe,Co)-rich α 1 phase is located in the cellular interior, while the Cr-rich α 2 phase concentrates in the cellular boundaries.

In this paper, the phase compositions, microstructures, atomic structures, and magnetic properties of Co-rich SmCo10 alloys prepared by arc-melting, annealing, and melt-spinning were studied. It was found that as-cast alloy is composed of Th2Zn17-type Sm2Co17 matrix with an average grain size of ∼45 μm accompanied by lamellar eutecticum (consisting of α-Co and Th2Zn17-type Sm2Co17) distributed at grain boundaries. The annealed alloy has the same phase composition and phase distribution as the as-cast alloy except that the average grain size decreases to ∼35 μm, and the eutecticum has more homogeneous distribution on the matrix. Simultaneously, the atomic structure of Sm2Co17 is unchanged with only a decrease in structural disorder after annealing. The as-spun ribbons are composed of ∼95.5 vol.% TbCu7-type Sm2Co17 and the rest α-Co. The short rod-shaped α-Co grains are intermittently distributed at the grain boundaries of equiaxed Sm2Co17 grains. The as-spun ribbons show a higher coercivity, and the annealed alloy shows maximum magnetization. The structural parameters were calculated by Extended X-ray Absorption Fine Structure (EXAFS), and the relationship between structure and magnetic properties was discussed in detail.

Hard/soft Sm-Co/Co nanocomposite particles were prepared by reducing CoCl 2 ·6H 2 O in the solution containing ball-milled Sm(Co, Hf) 7 particles by a simple polyol method with ethylene glycol as the solvent. Phase composition, microstructure and magnetic properties of the particles were analyzed by XRD, TEM (HRTEM) and VSM, respectively. It has been found that Sm-Co/Co core/shell structure is formed in which the Co shell is 3–5 nm in thickness and mainly exists in hcp-Co phase. At the same time, fcc-Co tends to nucleate and grow independently between Sm-Co particles. The formation mechanism of Sm-Co/Co composite particles is discussed and corresponding model is established. Sm-Co/Co composite particles perform obvious remanence enhancement effects especially after being heated at 450 °C for 15 min

This communication reports that the TiO2@polydopamine nanocomposite with a core-shell structure could be a highly active photocatalyst working under visible light. A very thin layer of polydopamine at around 1 nm was found to be critical for the degradation of Rhodamine B.

SmCo3.94−xFexCu0.06B (x = 0.7–2.0) ribbons were prepared by melt-spinning at 40 m/s accompanied by annealing at 800 °C for 30 min, and then their structures and magnetic properties were investigated. The results show that the annealed ribbons are composed of Sm(Co,Fe,Cu)4B and Sm5(Co,Fe,Cu)19B6 phases with a short rod-shaped microstructure at x = 0.7–0.9; Sm(Co,Fe,Cu)4B, Sm5(Co,Fe,Cu)19B6, and Sm2(Co,Fe,Cu)7B3 phases building a cellular one at x = 1.0; equiaxed Sm(Co,Fe,Cu)4B, Sm2(Co,Fe,Cu)14B, and Sm5(Co,Fe,Cu)19B6 phases at x = 1.5; or six phases at x = 2.0. The coercivity of annealed SmCo3.94−xFexCu0.06B ribbons increases gradually until it reaches a maximum of 50.1 kOe at x = 1.0, and then decreases with an increase in x. Moreover, the microstructure evolution models were established and the reason for their coercivity variation was analyzed by different coercivity mechanisms.