Fluorescent quantum dots (QDs) modified with polyethylene glycol (PEG) and albumin bovine serum (BSA) have profound application in the detection and treatment of hepatocellular carcinoma (HCC) cells. In the present study, the effects and mechanism of PEG and BSA modification on the cytotoxicity of QDs have been explored. It was found that the diameter of the as-prepared QDs, PEG@QDs, BSA@QDs is 3–5 nm, 4–5 nm, and 4–6 nm, respectively. With increase of the treatment time from 0 to 24 h, the HCC cell viability treated with QDs, PEG@QDs, and BSA@QDs obviously decreases, showing a certain time-dependent manner. When the concentration of several nanomaterials is increased from 10 to 90 nM, the cell viability decreases accordingly, exhibiting a certain concentration-dependent manner. Under the same concentration change conditions, the reactive oxygen species contents of cells treated by QDs, PEG@QDs, and BSA@QDs also rise from 7.9 × 103, 6.7 × 103, and 4.7 × 103 to 13.2 × 103, 14.3 × 103, and 12.3 × 103, respectively. In these processes, superoxide dismutase does not play a major role. This study provides strong foundation and useful guidance for QD applications in the diagnosis and treatment of HCC.

A series of xLiMn0.5Fe0.5PO4–yLi3V2(PO4)3/C (x:y= 4:1, 3:1, 2:1, 1:1, 1:2, and 1:3) composite cathode materials for lithium-ion batteries are successfully prepared by the rheological phase reaction method. The structures, morphologies, and electrochemical properties of these composite materials are studied. The results indicate that xLiMn0.5Fe0.5PO4–yLi3V2(PO4)3/C composites are composed of LiMn0.5Fe0.5PO4 and Li3V2(PO4)3 phases and mutual doping exists. The initial discharge capacities, initial Coulombic efficiencies, and capacity retentions of composites increase but then decline with the increase of Li3V2(PO4)3 content. All the composites show higher capacity retentions than LiMn0.5Fe0.5PO4/C and Li3V2(PO4)3/C single phases except LMFP–3LVP/C. The composite material of x:y= 1:1 exhibits remarkably superior electrochemical performance than the single phases and other composites both in discharge capacity and cycle performance, delivering the initial discharge capacity of 148.2 mA h/g (2.0–4.5 V) and 170.1 mA h/g (2.0–4.8 V) at 0.1 C. And the corresponding capacity retentions are 98.0 and 90.4% after 100 cycles, respectively.

Boronic ester bonds can be reversibly formed between phenylboronic acid (PBA) and triol moieties. Here, we aim at a glucose-induced shape-memory effect by implementing such bonds as temporary netpoints, which are cleavable by glucose and by minimizing the volume change upon stimulation by a porous cryogel structure. The polymer system consisted of a semi-interpenetrating network (semi-IPN) architecture, in which the triol moieties were part of the permanent network and the PBA moieties were located in the linear polymer diffused into the semi-IPN. In an alkaline medium (pH = 10), the swelling ratio was approximately 35, independent of Cglu varied between 0 and 300 mg/dL. In bending experiments, shape fixity Rf ≈ 80% and shape recovery Rr ≈ 100% from five programming/recovery cycles could be determined. Rr was a function of Cglu in the range from 0 to 300 mg/dL, which accords with the fluctuation range of Cglu in human blood. In this way, the shape-memory hydrogels could play a role in future diabetes treatment options.

Membranes with special wettability have attracted increasing interest for oil/water separation. Herein, the cellulose-based nanofibrous membrane was fabricated in an aqueous system by an electrospinning technique. The membrane was then modified successively through coating polydopamine and polyethyleneimine on the surface, which endowed the membrane with superhydrophilic and underwater superoleophobic character. The composition and morphology of the resultant membrane were characterized by attenuated total reflectance Fourier transform infrared spectra, X-ray photoelectron spectroscopy, and field-emission scanning electron microscope, respectively. Surfactant-stabilized oil-in-water emulsions were used to evaluate the separation performance of the membrane at different pH values. It was found that the membrane displayed the excellent antifouling property and separation performance for all different emulsions, with separation efficiency above 99.1% due to the development of a hydration layer underwater on the membrane surface. The reusability study indicated that the modification coating was stable enough to effectively separate emulsions after recycling at least 20 times. The developed nanofibrous membrane, as well as the corresponding modification strategy, enriched the application of membranes with special wettability in the field of oil spills and oily wastewater treatments.

In this paper, the microstructure and the shear property of Cu/In–45Cu/Ni solder joints by transient liquid phase were studied, and the intermetallic compounds (IMCs) growth mechanism was investigated. The results showed that the IMCs volume ratio of solder joints was increased firstly and then decreased with increasing bonding time, and the IMCs volume ratio reached its maximum value of 95.8% at 60 min. The Cu interfacial IMC of the solder joint with dense microstructure was Cu2In phase at 60 min, and the Ni interfacial IMC was Ni3In7. The maximum shear strength of solder joints was obtained at 60 min, which is 15.21 MPa. The shear fracture appeared honeycomb structure, and the fracture occurred at the phase interface of Ni3In7/Cu11In9. The thickness of the interfacial IMCs and the white IMCs around the Cu particles (Cu@IMC) was increased continuously with increasing bonding time, and thus, the interconnection of Cu–Ni substrates was realized ultimately.

Bamboo is a natural composite and one of the most efficient structures in nature because of the relationship of mechanical properties with its microstructural features. This research presents the 3D characterization of the reinforcement bundles of a branching nodal region of bamboo, through high-resolution X-ray microtomography (µCT). µCT was used to characterize a sample regarding the volume, relative density, and porosity of parenchyma and sclerenchyma tissues, and the resulting data were used to estimate their constitutive properties. A nonlinear finite element analysis (FEA) was performed based on a discretized model of the µCT to the limiting compressive load. Secondary bundles presented an interweaved arrangement into the primary vascular elements that distribute axial compressive stresses into new branches. Our findings suggest that the foam-like behavior of the parenchyma, the sclerenchyma thickening above the nodal zone, and the nodal vascular branching are ways for bamboo to protect important tissues from mechanical stress by allocating axial loads. In addition, such mechanism could be applied in the design of biomimetic structures with selective load-bearing capabilities.

Atomically thin 2D materials exhibit strong intralayer covalent bonding and weak interlayer van der Waals interactions, offering unique high in-plane strength and out-of-plane flexibility. While atom-thick nature of 2D materials may cause uncontrolled intrinsic/extrinsic deformation in multiple length scales, it also provides new opportunities for exploring coupling between heterogeneous deformations and emerging functionalities in controllable and scalable ways for electronic, optical, and optoelectronic applications. In this review, we discuss (i) the mechanical characteristics of 2D materials, (ii) uncontrolled inherent deformation and extrinsic heterogeneity present in 2D materials, (iii) experimental strategies for controlled heterogeneous deformation of 2D materials, (iv) 3D structure-induced novel functionalities via crumple/wrinkle structure or kirigami structures, and (v) heterogeneous strain-induced emerging functionalities in exciton and phase engineering. Overall, heterogeneous deformation offers unique advantages for 2D materials research by enabling spatial tunability of 2D materials' interactions with photons, electrons, and molecules in a programmable and controlled manner.

Nanocomposites of polyvinylidene fluoride loaded with various amounts of γ-Fe2O nanoparticles, with an average size ranging between 20 and 40 nm, have been obtained by melt mixing and investigated using various experimental techniques [Superconducting Quantum Interference Device, Mössbauer, and Thermogravimetric Analysis]. Magnetic and Mössbauer measurements confirmed the presence of maghemite and a trace of a paramagnetic iron compound. Magnetic data are consistent with a blocking temperature close to room temperature (RT), showing a decrease in the coercive field as the temperature is increased. A weak exchange bias was noticed in all nanocomposites investigated at all temperatures and tentatively ascribed to surface spin disorder. The temperature dependence of the coercive field obeys the Kneller law. The nanocomposites exhibit superparamagnetic behavior near RT. Most magnetic measurements have been performed below the blocking temperature, revealing thus a complex behavior. The dependence of the mass loss derivative versus temperature, as obtained by thermogravimetric analysis, exhibits a single peak due to the thermal degradation of the polymeric matrix. A weak increase in the thermal stability of the polymeric matrix upon loading with maghemite is reported.

The field of two-dimensional (2D) materials remains a key area of scientific research today, generating continual interest for electronic, sensing, and quantum technology. As the field progresses beyond proof-of-concept devices, experimental and analytical methods and results must be scrutinized to ensure the veracity of scientific claims. Here, some favored synthesis and characterization techniques within the 2D material (2DM) community and certain limitations inherent to these techniques are discussed. The authors highlight select caveats of solid-source and seed-promoted synthesis techniques, such as difficulties in reproducibility and compromised electrical performance of films synthesized with nucleation agents. Furthermore, the importance of careful characterization methodology in determining 2DM layer number, stoichiometry, and dopant effects is discussed. This article is intended to further educate researchers regarding select techniques and claims in the 2DMs field.

Polysaccharide-based nanoparticles such as pectin had always been of greatest interest because of its excellent solubility and mucoadhesive nature and are highly suitable for oral drug delivery for drug administration. In this study, we used commercially available pectin samples based on their degree of esterification, and nanoparticles were fabricated by the ionotropic gelation method using magnesium (Mg2+) as the divalent cross-linker. We conducted a comparative analysis on the three pectin NPs—high methoxylated pectin (HMP), low methoxylated pectin (LMP), and amidated LMP (AMP)—to examine the difference in characteristics such as shape, size, and biocompatibility. HMP and AMP were found to be similar in size (~850 nm), whereas LMP was found to be of ~700 nm. The three NPs were also tested for their biocompatibility toward THP-1 cells. All three NPs were found to have the potential as a nanocarrier of therapeutic and preventive drugs, especially through oral routes.

In this research, a novel titanium metallic composite, Ti6Al4V powder mixed with 5 at.% Nb powder, was fabricated by selective laser melting (SLM). The effect of Nb addition on their phase transformation, microstructure evolution, mechanical properties, and corrosion behavior were studied. Interestingly, the novel alloy shows a combination of superior plastic deformation (εp= 18.9 ± 1.8%) and high compressive strength (σc= 1593 ± 38 MPa), which is 60.2 and 3.2% higher than that of the SLM-processed Ti6Al4V alloy under optimum printing parameters, respectively. However, the yield strength of Ti6Al4V + 5Nb (973 ± 45 MPa) is lower than that of the Ti6Al4V alloy (1066 ± 12 MPa). The solidification mechanism changes from planar to cellular mode with Nb addition. The ultrafine microstructure β grains are observed, which show a columnar shape and cellular shape. More importantly, the volume fraction of the β phase is significantly increased from 3.7% to 20.4% because of the Nb addition. In addition, the Ti6Al4V + 5Nb alloy possesses better corrosion resistance than the Ti6Al4V alloy. The research highlights that the addition of Nb powder in Ti6Al4V processed by SLM can improve the mechanical properties and corrosion resistance of the material.

The thickness effect has a significant influence on the fatigue life of micro–nanometer thin films. Due to the increasing application of micro–nanometer thin films in the field of microelectronics, a suitable fatigue prediction model is urgently needed. To reveal the impact of the thickness effect on the fatigue life of a copper wire film, cyclic tension fatigue test of four groups of copper wire films were carried out. Based on the theory of continuous damage mechanics and damage homogenization method, a fatigue damage accumulation model that considered the film thickness was proposed. Based on the proposed fatigue damage prediction model, the damage evolution law and fatigue life of copper wire films with different thickness and strain range were predicted. Furthermore, the size effect of the copper films was analyzed. The results showed that the fatigue life of copper wire films will decrease with the increase of thickness and strain amplitude; the thinner the film, the more significant the thickness effect on the fatigue life is; with the increase of the film thickness, the film thickness effect will gradually decrease.

Twin–twin interactions (TTIs) take place when multiple twinning modes and/or twin variants are activated and interact with each other. Twin–twin junctions (TTJs) form and affect subsequent twinning/detwinning and dislocation slip, which is particularly important in determining mechanical behavior of hexagonal metals because twinning is one major deformation mode. Atomic-level study, including crystallographic analysis, transmission electronic microscopy (TEM), and molecular dynamics (MD) simulations, can provide insights into understanding the process of TTIs and structural characters associated with TTJs. Crystallographic analysis enables the classification of TTIs and the prediction of possible interfaces of twin–twin boundaries (TTBs), characters of boundary dislocations, and possible reactions of twinning dislocations and lattice dislocations at TTBs. MD simulations can explore the process of TTIs, microstructures of TTJs, atomic structures of TTBs, and stress fields associated with TTJs. The predictions based on crystallographic analysis and the findings from MD can be partially verified by TEM. More importantly, these results provide explanation for microstructural characters of TTJs and guidance for further TEM characterizations.

Organic light-emitting diodes (OLEDs) have aroused great attention due to the advantages of high luminescent efficiency, fast response time, wide viewing angle, and the compatibility with the flexible electronics. Nevertheless, the organic luminescent materials are vulnerable to environment moisture/oxygen. Thus, how to protect the OLEDs from the ambient moisture/oxygen erosion is of great importance to ensure the stability and reliability. Thin film encapsulation (TFE) via atomic layer deposition (ALD) has emerged as a potential method to meet the encapsulation requirements of OLEDs due to its unique assets. In this review, the challenges of TFE, including pinholes, crystallization, cracks, and overheated, are introduced first. The ALD-based monolayer, composite structures, and hybrid laminates were developed to improve the barrier property, flexibility, and thermal conductivity. Besides, the ALD reactors and processes for TFE are also reviewed. Finally, the challenges remained and future development in the stabilization of OLEDs via ALD are also discussed.

Synthetic cationic polymer-mediated synthesis of silver nanoparticles and selective antimicrobial activity of the same were demonstrated. Polyethyleneimine (PEI)-coated silver nanoparticles showed antimicrobial activity against Acinetobacter baumannii as a function of the polymeric molecular weight (MW) of PEI. Silver nanoparticles were coated with PEI of three different MWs: Ag-NP-1 with PEI exhibiting a MW of 750,000, Ag-NP-2 with PEI exhibiting a MW of 1300, and Ag-NP-3 with PEI exhibiting a MW of 60,000. These nanoparticles showed a particle size distribution of 4–20 nm. The nanoparticles exhibited potent antimicrobial activity against A. baumannii, with the minimum inhibitory concentration of Ag-NP-1, Ag-NP-2, and Ag-NP-3 on the order of 5, 10, and 5 μg/mL, respectively, and minimum bactericidal concentration of Ag-NP-1, Ag-NP-2, and Ag-NP-3 on the order of 10, 20, and 10 μg/mL, respectively. Fluorescence imaging of Ag-NPs revealed selective transfusion of Ag-NPs across the cell membrane as a function of the polymeric MW; differential interaction of the cytoplasmic proteins during antimicrobial activity was observed.

An atomistic kinetic Monte Carlo coupled with the embedded-atom method is used to simulate film growth and morphology evolution of a Cu–Zn–Sn precursor of Cu2ZnSnS4 solar cells by single-step electrodeposition. The deposition and diffusion events of three different metallic atoms are described by the simulation. Moreover, the multibody Cu–Zn–Sn potential is used to calculate diffusion barrier energy. The effects of process factors, including temperature and electrode potential, on the cross-section morphology and surface roughness are explored, while keeping the elemental composition ratios constant. The lowest roughness with the smoothest morphology is obtained at the optimal parameters. The distribution and transformation behaviors of cluster sizes are investigated to describe the alloy film growth process. Furthermore, the comparison between deposition events and diffusion events reveals that deposition events depend primarily on individual deposition rates of different metallic atoms, but diffusion events are mainly dependent on the interaction of metallic atoms. The film morphology evolution is visualized by three-dimensional configuration with increasing numbers of atoms, which suggests a competing mechanism between nucleation and growth of the thin film alloy.

The capability of borospherene to detect radioactive pollutants (radon and radium) is investigated utilizing density functional theory and nonequilibrium Green's function regime. The quantum transport is evaluated by calculating the density of states, chemical potential, transmission and molecular energy spectra, highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap, electron densities, current–voltage curve, and differential and quantum conductance. LUMO-mediated transmission is observed in all the cases. The conduction considerably declines in B40 molecular junction doped with radioactive pollutants in comparison to pure B40 molecular junction. This decrease in conduction is due to reduced electron density and higher chemical potential in doped B40 junctions. Due to different values of current and differential conductance, we propose utilization of B40 in detecting the presence of radioactive pollutants in underground water. Also, all molecular junctions assay lifting of Coulomb blockade at equilibrium state; thus, these devices can be effectively utilized in single-electron transistor applications.

Lead sulfide (PbS) is having tremendous applications in the field of optoelectronics. Hence, a facile low temperature synthesis of PbS with different contents of terbium (Tb) has been achieved and investigated for structure–optic–dielectric–electrical properties. The structure confirmation was observed through the X-ray diffraction and Rietveld refinement process which approved a monophasic cubic structure. Rietveld refinement gives a best-fitting profile of the prepared products. The crystallite size was estimated to be in range of 15–21 nm. FT-Raman study also approved the single-phase PbS with all characteristic modes. For further confirmation of composition, homogeneity, and Tb in the final product, the EDX/SEM e-mapping was carried out. The morphological investigation was carried out through SEM which revealed that the shape and size are greatly influenced by Tb content addition in PbS. The energy gap (Eg) was estimated in the range of 1.42–1.62 eV for all Tb@PbS, and the largest Eg value was observed for 0.5 wt% Tb@PbS. The dielectric constant values are calculated in the range of 16–25 in the tested frequency region. The ac electrical conductivity was enhanced with frequency, and a charge transport mechanism is related to a correlated barrier hoping model in the prepared samples.

This study focuses on binary droplet collisions of equal calcium–magnesium–aluminosilicate (CMAS) droplets formed by the melting of dust and sand ingested by gas turbine engines. Head-on, off-center, and grazing collision of 1 mm CMAS droplets traveling toward each other at a relative velocity of 100 m/s are numerically investigated using a volume-of-fluid-based direct numerical simulation approach at operating pressure and temperature of 20 atm and 1548 K, respectively. It is found that head-on and off-center collisions lead to droplet coalescence, whereas stretching behavior is observed for the grazing configuration. To elucidate the effect of viscosity, a fictitious fluid with all properties the same as CMAS except for viscosity (1/10 of CMAS) is also studied. It is found that the lower viscosity liquid deforms significantly as compared to CMAS for the head-on and off-center cases. These differences are quantified using the budgets of kinetic, surface, and dissipation energies. This paper represents the first study of its kind on the binary collision of CMAS droplets.

The fracture toughness of 617 Ni-based weld metal (WM) under different elevated temperatures was tested with a novel method and its fracture mechanism was investigated in this paper. It was found that the fracture toughness of WM was lower than that of base metal (BM) at the same temperature, which was mainly due to the coarse columnar structure, differences in misorientation, and precipitated phases. For both BM and WM, the fracture toughness was lower at elevated temperature due to decreased strength. Much more micro-voids caused by Ti(C, N) and M23C6 inside grains of BM could be observed adjacent to the crack path, which accounted for the dramatically decreased fracture toughness of BM at elevated temperature. In comparison, fewer micro-voids could be observed in WM due to the lack of those second particles. As a result, the J0.2 value and propagation path morphology both showed that the WM had more stable microstructure even though possessing lower toughness.