M3:2 high-speed steel (HSS) billets with or without Nb addition were prepared by spray deposition. The effects of Nb and post-thermal-mechanical processing (decomposition treatment and hot forging), as well as heat treatment, on the microstructure and properties of M3:2 HSS were investigated. The microstructure of the as-deposited M3:2 HSS consisted of equiaxed grains with a mean size of approximately 25 μm and discontinuous plate-like M2C and irregular MC carbides distributed along grain boundaries. 0.5% Nb addition can refine the M2C plates and spheroidize MC carbides. With 2% Nb addition, the refined grains with a mean size of approximately 12 μm and continuous net of M6C and a uniform distribution of NbC carbides were obtained. The decomposition of metastable M2C carbides can be accelerated with 0.5% Nb addition due to the refined size and lower thermodynamic stability of M2C plates. With the increased degree of decomposition of M2C carbide, the M6C and MC carbides became refined and more uniformly distributed after optimal thermal-mechanical processing and heat treatment, which leads to a significant increase in bend strength and toughness.

As rarely large flake graphite (9 mesh) was recently exploited in China, it was innovatively developed as the raw material to prepare a novel wound dressing based on large expanded graphite (EG) in this work. The EG worms were prepared in an easy oxidative intercalation and thermal expansion method. Afterward, chitosan was grafted onto the surface of EG by chemical modification, forming CS-EG worms. CS-EG sponge dressings were then obtained by pressing a number of CS-EG worms together by external force. Due to the porous structure and large specific surface area, the produced CS-EG sponges exhibited outstanding adsorption capacity for wound exudate. They could also promote blood coagulation by adsorbing the blood cells and proteins quickly and effectively, showing excellent hemostatic performance. The eminent performances and the simple preparation process ensure the great application potential of CS-EG as a dressing material. This is also the first time to report the application of the traditional carbon material, EG, to act as a dressing material after chemical modification.

When a metal oxide surface is immersed in aqueous solution, it has the ability to bind, orient, and order interfacial water, affecting both chemical and physical interactions with the surface. Structured interfacial water thus possesses time-averaged, spatially varying polarization charge and potential that are comparable to those arising due to ion accumulation. It is well established that interfacial water structure propagates from the surface into bulk solution. Here, we show that interfacial water structure also propagates laterally, with important consequences. The constant pH molecular dynamics was used to impose a pH difference between opposite faces of a model goethite (α-FeOOH) nanoparticle and quantify water polarization charge on intervening faces. We find that the structure of water on one face is strongly affected by the structure on nearby surfaces, revealing the importance of long-range lateral hydrogen bonding networks with implications for particle aggregation, oriented attachment, and processes such as dissolution and growth.

In this paper, the influence of strain rate on the mechanical behavior of high-strength low-alloy (HC420LA) steel were studied. Quasi-static and dynamic tensile experiments were performed with strain rates ranging from 0.001 to 500 s−1 at room temperature. The digital image correlation technique was used to obtain the full-field strain. The experimental results showed that HC420LA steel exhibited positive strain rate sensitivity. Based on experimental results, the modified Johnson–Cook (J–C) model was used to model the constitutive behavior of HC420LA steel. Predictions of the standard and modified J–C models were compared using standard statistical parameters. The modified J–C model showed better agreement with the experimental data. Then, numerical simulation of the representative tensile test at a strain rate of 100 s−1 was performed using the finite element code LS-DYNA. Good correlation between the experimental and numerical simulation results was achieved.

We assess the validity of criteria based on size mismatch and thermodynamics in predicting the stability of the rare class of high-entropy alloys (HEAs) that form in the hexagonal close-packed crystal structure. We focus on nanocrystalline HEA particles composed predominantly of Mo, Tc, Ru, Rh, and Pd along with Ag, Cd, and Te, which are produced in uranium dioxide fuel under the extreme conditions of nuclear reactor operation. The constituent elements are fission products that aggregate under the combined effects of irradiation and elevated temperature as high as 1200 °C. We present the recent results on alloy nanoparticle formation in irradiated ceria, which was selected as a surrogate for uranium dioxide, to show that radiation-enhanced diffusion plays an important role in the process. This work sheds light on the initial stages of alloy nanoparticle formation from a uniform dispersion of individual metals. The remarkable chemical durability of such multiple principal element alloys presents a solution, namely, an alloy waste form, to the challenge of immobilizing Tc.

Hierarchical nanostructure of TiO2 nanoparticles/nanorod arrays (TiO2 NPs/NRs) is synthesized and applied in dye-sensitized solar cells (DSSCs) comparing with the TiO2 nanorod (TiO2 NR) arrays and the TiO2 nanoparticles (TiO2 NPs). The TiO2 NP/NR surface morphology is revealed by X-ray diffraction, field emission scanning, and transmission electron microscopy. The power conversion efficiency of NP/NR-based DSSCs (length 3 μm) is improved to 3.47%, which is 2.2 times higher than the NR-based DSSCs (length 3 μm), and rivals the NP-based DSSC (length 5 μm). The high photovoltaic performance was attributed to that the TiO2 NP/NR photoanode has large surface area and exhibits excellent light scattering, allowing for fast interfacial charge transfer and less charge recombination, which are characterized using the UV-vis absorbance spectra, Brunauer–Emmett–Teller (BET) surface area, electrochemical impedance spectroscopy (EIS) measurements, and photoluminescence (PL) spectroscopy. However, further work is needed to overcome the limitations of TiO2 NP/NR and improve the performance of TiO2 NP/NR-based DSSC.

The interaction between water and oxide surfaces plays an important role in many technological applications and environmental processes. However, gaining fundamental understanding of processes at oxide–water interfaces is challenging because of the complexity of the systems. To this end, results of experimental and computational studies utilizing well-defined oxide surfaces help to gain molecular-scale insights into the properties and reactivity of water on oxide surfaces. This is a necessary basis for the understanding of oxide surface chemistry in more complex environments. This review highlights recent advances in the fundamental understanding of oxide–water interaction using surface science experiments. In particular, we will discuss the results on crystalline and well-defined supported thin film oxide samples of the alkaline earth oxides (MgO and CaO), silica (SiO2), and magnetite (Fe3O4). Several aspects of water–oxide interactions such as adsorption modes (molecular versus dissociative), formation of long-range ordered structures, and dissolution processes will be discussed.

Serrated flow is one important characteristic of shear bands through which metallic glasses (MGs) accommodate plastic deformation. Serrated flow can be affected by intrinsic properties such as elastic modulus or extrinsic variables such as strain rate. However, the influences of pre-deformation and interfaces on serrated flow are less well understood. In this study, by using in situ micropillar compression inside a scanning electron microscope, we show that pre-deformation (consisting of cyclic loading/unloading below the nominal elastic limit) suppresses serrated flows in amorphous-CuNb but enhances serrated flows in amorphous-CuZr at both high and low strain rates. Moreover, layer interfaces in Cu/amorphous-CuNb multilayers mitigate serrated flows, and the average stress drop and strain duration associated with shear banding process can be tailored. Strain accommodation and energy dissipation via shear banding have clear impact on serrated flows. This study provides new perspectives on tailoring serrated flows and enhancing plastic deformation of MGs.

Nanocrystalline (NC) and ultrafine-grained (UFG) CoCrCuFeNi high-entropy alloy (HEA) with grain size ranging between 59 and 386 nm was produced via powder metallurgy and heat treatment. The as-sintered HEA exhibited two face-centered cubic (FCC) phases (CoCrFeNi-rich and Cu-rich phases) and a small grain size (59 nm), whereas the alloy after heat treatment at 1000 °C exhibited a CoCuFeNi-rich phase with FCC structure and relatively larger grain size (386 nm). Moreover, the yield strength decreased from 1930 to 883 MPa, and plastic strain to failure increased by 8–32%. In terms of microstructural evolution, grain boundary strengthening coupled with lattice distortion was the dominant strengthening mechanism for NC HEAs. Furthermore, the coefficient for boundary strengthening was higher in the HEAs than in the corresponding pure elemental metals with FCC structure, possibly because of significant lattice distortion. The UFG HEAs exhibited high strength and good ductility because of the activation of dislocation.

In the present study, the phase evolution and microstructure of CrMoNbTiW, a new equi-atomic refractory high-entropy alloy, are studied. The alloy was synthesized through mechanical alloying (MA) followed by consolidation using spark plasma sintering. After MA, a major BCC solid solution along with residual Cr and Nb were observed. However, secondary phases such as Laves and carbides were also observed in addition to the major BCC solid solution after sintering. Unsolicited contamination from the milling media is found to be one of the reasons for the formation of secondary phases. The high hardness of 8.9 GPa after sintering was attributed to the presence of secondary phases along with the nanocrystalline nature of the alloy. To understand the phase evolution, calculation of phase diagram was carried out using CALPHAD. Further, binary phase diagram inspection and simple empirical parameters were also used to assess their effectiveness in predicting phases.

Graphene (G) has attracted great interest because of its excellent chemical and electrical properties. However, the aggregation of graphene restricts its application. Herein, linoleic acid sodium salt (LASS), a low-cost and environmentally friendly material, was used to improve the dispersion of graphene through covalent interaction. Then, the mixture (G@LASS) was integrated with acrylic resin matrix via hydrogen bond between the carboxyl and ester groups. The excellent interfacial compatibility between G@LASS and acrylic matrix, as well as good dispersibility of G@LASS, was demonstrated by Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman, and scanning electron microscopy tests. Compared with acrylic matrix, the surface hydrophobicity of G@LASS@Acrylic increased considerably because of its compact structure. G@LASS@Acrylic composites meet the requirement of antistatic materials when the content of G was only about 0.5 wt%. The results showed that conductive pathways were established successfully through this method.

Interfaces can influence the mechanical properties of metallic multilayers, even between different combinations of face-centered cubic (FCC)/body-centered cubic (BCC) constituents, as reported from many experiments. Recent literature has shown promise for fracture being delayed or even stopped at these interfaces. However, no studies have investigated the influence of their constituents on the subsequent mechanisms of fracture leading to failure. We performed in situ microfracture bending tests of the notched clamped beams made from physical vapor deposited Cu/Nb and Al/Nb multilayers. A catastrophic, linear elastic, brittle fracture was observed for the Cu/Nb beams, whereas a more delayed fracture with a gradual crack propagation was observed for the Al/Nb beams. These observations reveal differences in mechanisms because of the FCC element, interface/boundary blocking of dislocation motion, and effect of grain boundaries in the multilayers. Through this study, FCC/BCC metallic multilayers can be designed with enhanced fracture resistance and mechanical strength.

Numerous studies have reported that amyloid-beta 42 (Aβ-42) protein is a high-profile risk factor associated with the onset and progression of Alzheimer’s disease (AD). Accumulation of extracellular senile plaques, synaptic degeneration, and intracellular neurofibrillary tangles were recorded as essential features that facilitate the onset of Aβ-42, resulting in AD. Hence, we attempted a new screening technique to discover potential inhibitors against Aβ-42 using an in silico deep neural network approach. We screened PubChem compounds library and found wgx-50 as a potential inhibitor of Aβ-42. Also, synergistic effects of wgx-50–gold nanoparticles (AuNPs) complex induced significant inhibition of Aβ-42, compared with those of wgx-50 alone. Further, molecular docking analysis, systems biology approach, and time course simulation confirmed that synergistic effects of wgx-50–AuNPs complex have potential application in the treatment for AD. Additionally, we proposed the biological circuit for AD induced by Aβ-42 that can be used to monitor the effect of drugs on AD.

3D ordered bimodal mesoporous carbon (OBMC) with a high specific surface area of 1368.7 m2/g, ordered large mesopores, and small mesopores on the walls is prepared by a surfactant-free rapid method using SiO2 nanosphere arrays as templates. The resulting OBMC is then composited with sulfur to prepare S/OBMC hybrids via a simple solution infiltration method followed by a heat treatment process. In S/OBMC composite, sulfur is uniformly infiltrated inside the 3D hierarchical pores of OBMC. On the basis of this systematic design, the obtained S/OBMC cathode shows a large discharge capacity value of 1590 mA h/g at first cycle and maintains 989 mA h/g after 100 cycles at 0.2 C. Furthermore, at 1 C charge–discharge rate, a reversible discharge capacity of 733 mA h/g after 100 cycles is reached. The extraordinary electrochemical property of S/OBMC derives from the unique bimodal mesoporous structure with large mesopores and small mesopores that can facilitate the mass transfer and strict dissolution of polysulfide species into the electrolyte.

We have investigated the adsorption and dissociation of water and its co-adsorption with CO on atomically defined cobalt oxide nanoislands on Pt(111). The CoO islands were prepared under ultrahigh vacuum (UHV) conditions by reactive deposition of Co metal in oxygen atmosphere. The island structure was characterized by scanning tunneling microscopy (STM), showing that the nanoislands consist of a CoO bilayer and are regularly shaped with island edges that are mainly terminated by Co2+ ions. D2O was dosed in UHV onto the CoO islands on Pt(111) after pre-saturation with CO. D2O dissociation was monitored in situ by isothermal and temperature programmed infrared reflection absorption spectroscopy (IRAS). Isotopic exchange experiments were performed with H2O, D2O, and D218O to elucidate the nature of the hydroxyl groups. Three principal types of OD species are identified: (i) isolated OD at the edges of the CoO islands (Co-OeD), (ii) OD groups within larger hydroxylated areas on the CoO islands (Co-OcD), and (iii) isolated OD groups on the CoO terraces (Co-OtD). At 400 K, water adsorbs dissociatively on the CoO islands and forms isolated hydroxyl species (Co-OeD) at the island edges only. At room temperature (300 K), the coverage of hydroxyl groups increases rapidly, in line with the water-assisted hydroxylation reaction suggested previously. Adsorption experiments with D218O suggest that two equivalent groups are formed from one water molecule after dissociation at island edges, leading to the formation of larger hydroxylated areas on the CoO islands (Co-OcD) and, in addition, isolated OD species on the CoO terraces (Co-OtD). While the initial step of D2O dissociation is facile, the formation of larger hydroxylated areas is a slow and irreversible process. At 200 K, the formation of hydroxylated areas is accompanied by the co-adsorption of molecular water. The hydroxyl groups on the CoO islands are shown to interact with the CO preadsorbed on the CoO/Pt(111) model system. In particular, we observe a new CO species, stabilized by OD groups on the CoO islands, which adsorbs much stronger than CO on the OD-free CoO surface.

Considering the nonlocal small-scale effect and surface effect, we perform the size-dependent vibration analysis of carbon nanotube (CNT). The modified governing equations for CNT’s vibration behaviors are derived by using the nonlocal Euler–Bernoulli and Timoshenko beam models, together with the consideration of surface tension and surface elasticity. According to the numerical experiments, both small-scale effect and surface effect make a substantial difference. For flexural vibration, size effect for CNT’s vibration behaviors weakens with the increase of its diameter, but strengthens with the increase of the length–diameter ratio; for shear vibration with constant length–diameter ratio, a nonlinear correlation between size effect and CNT’s diameter exists, suggesting that there is a typical diameter for CNTs, which corresponds to the “strongest” size effect. In addition, the effects of elastic substrate modulus, temperature change, and axial preloading on the vibration behaviors and their size-dependence are analyzed, respectively.

Theoretical models for the strength and ductility of high-order hierarchically nanotwinned metals are developed, and especially analytical expressions of mechanical parameters with various influencing factors are deduced. Furthermore, the size effect on mechanical properties is analyzed based on these mechanism-based plasticity models, wherein the effects of twin spacing and grain size on the strength and ductility are discussed systemically. Related analysis demonstrates that the twin spacing plays an important role. Through adjusting the twin spacing of the primary layer of twin lamellae and optimizing the combination of twin spacing of the high-order layers, expected mechanical properties with high strength and high ductility could be achieved. Besides, the grain size also has a significant effect, and the reduction in grain size still induces a positive effect on the strength, whereas a negative effect on the ductility. Finally, a material design approach for the optimization of comprehensive mechanical properties is suggested.

Polyurethanes (PUs) were synthesized with polyols derived from castor oil and isophorone diisocyanate. The materials were evaluated for their mechanical properties using stress–strain curves, thermogravimetric analysis, differential scanning calorimetry, and contact angle analysis. The biological response of the materials was evaluated by determining their cell viability in vitro, antimicrobial activity against Escherichia coli and Pseudomonas aeruginosa, and biological response in vivo of PUs by means of implanting them in Wistar rats. The cell proliferation on the materials was analyzed using mouse fibroblast L929, human fibroblast MRC-5, and adult human dermal fibroblast (HDFa) cells by the ISO 10993-5 method. The materials showed no toxic effects and promoted cell proliferation. Experiments performed in vivo for 30 days in mice showed that the materials neither affected the wound healing process nor caused adverse effects or severe injuries in the dorsal mid-cervical tissue or organs on histological evaluation. PUs synthesized can be used in biomedical devices.

In this study, Sr-incorporated nano-assembled hydroxyapatite structures (HASr) on 316L stainless steel bone plates were prepared by a biomimetic method induced by 10× simulated body fluid (SBF). First, HASr was coated on bone plates by the interaction of ions with 10× SBF containing different concentration of strontium ions. Then, silver coating is achieved as a second layer on bone plates. The cumulative release of strontium ions (Sr2+) and silver ions (Ag+) from multilayered HASr-Ag bone plates at the end of 15 days was in the range of 0.016–0.085 mM and 0.064–0.135 mM, respectively. The release mechanism for the bone plates was evaluated by several mathematical models that best fit the release data. The results showed that Sr2+ and Ag+ are released from multilayered bone plates by diffusion, whereas the release of Ag+ is not occurred by diffusion, instead the mechanism is dissolution, when silver is coated alone on bone plates.

A series of optically transparent and colorless semi-fluorinated poly(ether imide)s (PEIs) (III) were prepared from non-fluorinated 1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride (HQDPA) with various trifluoromethyl-substituted diamines. The III series showed more colorless and higher optical transparency with a cutoff absorption wavelength (λ0) below 370 nm than the IV series based on the corresponding non-fluorinated analogues and V series derived from CF3-free pyromellitic dianhydride (PMDA). Compared with the fluorinated VI series based on fluorinated 4,4′-hexafluoroisopropylidenediphthalic anhydride (6FDA), the semi-fluorinated III series not only exhibited much better optical transparency, but also had better mechanical and thermal properties. The III series had a tensile strength of 79.8–109.5 MPa, modulus of elasticity of 3.0–7.7 GPa and elongation at break of 14.2–26.7%, together with glass-transition temperatures (Tg) ranging from 214.3 to 265.1 °C and temperatures of 5% weight loss (T5%) beyond 530 °C. Meanwhile, the novel semi-fluorinated PEI IIIb was optically transparent and colorless with a λ0 of 367 nm coupled with dielectric constants below 3.2 and contact angles against water over 112°. In particular, the optically transparent IIIa exhibited the best tensile strength of 109.5 MPa when compared with already reported counterparts.