Increasing the number of quantum bits while preserving precise control of their quantum electronic properties is a significant challenge in materials design for the development of semiconductor quantum computing devices. Semiconductor heterostructures can host multiple quantum dots that are electrostatically defined by voltages applied to an array of metallic nanoelectrodes. The structural distortion of multiple-quantum-dot devices due to elastic stress associated with the electrodes has been difficult to predict because of the large micrometer-scale overall sizes of the devices, the complex spatial arrangement of the electrodes, and the sensitive dependence of the magnitude and spatial variation of the stress on processing conditions. Synchrotron X-ray nanobeam Bragg diffraction studies of a GaAs/AlGaAs heterostructure reveal the magnitude and nanoscale variation of these distortions. Investigations of individual linear electrodes reveal lattice tilts consistent with a 28-MPa compressive residual stress in the electrodes. The angular magnitude of the tilts varies by up to 20% over distances of less than 200 nm along the length of the electrodes, consistent with heterogeneity in the metal residual stress. A similar variation of the crystal tilt is observed in multiple-quantum-dot devices, due to a combination of the variation of the stress and the complex electrode arrangement. The heterogeneity in particular can lead to significant challenges in the scaling of multiple-quantum-dot devices due to differences between the charging energies of dots and uncertainty in the potential energy landscape. Alternatively, if incorporated in design, stress presents a new degree of freedom in device fabrication.

Wearable electrochromic devices are considered as the essential components for the development of smart clothing with the intelligent sensing, actuating, and displaying functions. In this study, the electrochromic composite flexible membranes of polyaniline (PANI) and reduced graphene oxide (RGO) were fabricated by in situ polymerization of aniline monomer in the presence of RGO dispersion. The effects of RGO concentration on the morphology, chemical structure, crystallinity, and electrochromic behavior of the composite membranes were studied. Our experimental results show that the conductivity of PANI/RGO composite membrane increases with the increasing of RGO concentration from 0.1 to 0.25 wt%, and the highest conductivity is 3.57 S/cm. An improved electrochemical performance with good electrochromic cycle characteristic of the PANI/RGO composite can be obtained, which shows a wide color range from green to black compared with the PANI membrane that ranging from green to dark blue. This research provides a systematical investigation of flexible PANI-based electrochromic membrane, which has the potential application in the field of wearable electrochromic devices in the future.

Sol–gel spin coating is applied to fabricate the pure and different concentrations of aluminum (Al)-doped ZnO films on high-quality silicon substrates. All films are showing high crystallinity in X-ray diffraction study, and lattice constants were obtained using PowderX software. The value of crystallite size was found in range of 20–40 nm. EDX/SEM mapping was performed for 2 wt% Al-doped ZnO film, which shows the presence of Al and its homogeneous distribution in the film. SEM investigation shows nanorods morphology all over the surface of films, and the dimension of nanorods is found to increase with Al doping. The E(g)dire. values were estimate in range of 3.25–3.29 eV for all films. Linear refractive index was found in range of 1.5–2.75. The χ1 value is found in range of 0.13–1.4 for all films. The χ3 values are found in range of 0.0053 × 10−10 to 6.24 × 10−10 esu for pure and doped films. The n2 values were also estimated. These studies clearly showed that the properties of ZnO have been enriched by Al doping, and hence doped films are more appropriate for optoelectronic applications.

We report the first synthesis of highly homogenous Ce-doped YAG/ZnO core/shell nanoparticles (YAG:Ce/ZnO CSN) based on the hydrolysis/condensation of Zn(OAc)2 on the surface of YAG:Ce nanoparticles (NPs). Results show that YAG:Ce NPs of about 100 nm diameter are homogenously surrounded by a multilayer of highly crystallized ZnO nanocrystals (ZnO NCs) of 10–15 nm diameter with a core/shell structure. The as-prepared nanostructures have been used in the photocatalytic degradation of sulfathiazole (STZ), which is a molecule widely used as antibiotic, under UV-vis and visible light. The effect of YAG:Ce/ZnO weight ratio and YAG:Ce particle size on the photocatalytic efficiency of YAG:Ce/ZnO core/shell structures has been studied. The YAG:Ce/ZnO weight ratio of 1/1 was found to yield the optimal photocatalytic activity. Results also showed that YAG:Ce/ZnO CSN with 100 nm core size exhibited much higher photocatalytic activity compared to YAG:Ce/ZnO CSN with micro-sized YAG;Ce core. The recyclability of YAG:Ce/ZnO CSN photocatalyst was also demonstrated over at least 10 photocatalytic degradation cycles.

We report the development of a sensitive and a label-free electrochemical immunosensing platform for the detection of cardiac biomarker troponin I (cTnI) using tungsten trioxide nanorods (WO3 NRs). The low-temperature hydrothermal technique was employed for the controlled synthesis of WO3 NRs. Thin films of 3-aminopropyltriethoxy saline (APTES)-functionalized WO3 NRs were deposited on indium tin oxide (ITO)-coated glass substrate (0.5 cm × 1 cm) using electrophoretic deposition technique. The covalent immobilization of cTnI antibody onto functionalized WO3 NRs electrode was accomplished using EDC-NHS [1-(3-(dimethylamino)-propyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysulfosuccinimide] chemistry. The structural and morphological characterizations of WO3 NRs and functionalized WO3 NRs were studied using X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and electrochemical techniques. The impedimetric response study of the proposed immunosensor demonstrates high sensitivity [6.81 KΩ mL·cm2)] in a linear detection range of 0.01–10 ng/mL. The excellent selectivity, good reproducibility, and long-term stability of the proposed immunosensing platform indicate WO3 NRs as a suitable platform for the development of a point-of-care biosensing device for cardiac detection.

Poly(ethylene glycol) (PEG)-based materials can potentially be used as biomechanical matrices in regenerative medicine and tissue engineering implants including the replacement of intervertebral (IV) disks. Glycerol and other generally recognized as safe (GRAS) plasticizers (low-MW PEG, propylene glycol, and sorbitol) were added to the bulk PEG matrix and gelled using chemical and photochemical methods at different temperatures (21, 37, 59, and 80 °C) and pressures (0 and 90 MPa gauge) settings, and their compression testing properties were acquired and analyzed. Surface incorporation of custom-made bioactive glass particles shortened the blood clotting time (78% compared to no glass particles), while alginate and laponite additives improved the gel’s mechanical properties to 645 kPa compressive modulus, 12% yield strain, and 79 kPa yield strength. This IV disk-modeled hydrogel system endured the cyclic loading and unloading tests at 4% compressive strain indicative of an elastic response, but required improvement to its biomechanical tolerance for downstream bioengineering applications.

This paper describes the fabrication of polyelectrolyte microspheres using porous manganese carbonate as a sacrificial template for entrapped photosensitizer (PS) drugs for photodynamic therapy application. These particles were used as templates for polyelectrolyte layer-by-layer assembly (Lbl) of two oppositely charged polyelectrolytes: poly(styrene sulfonate) and poly(allylamine hydrochloride). When the polyelectrolyte multilayer shell was built around the MnCO3 core by the Lbl protocol and the core was extracted with acid solution and EDTA, the resultant assembly consisted of hollow polyelectrolyte spheres. Chloroaluminum phthalocyanine was chosen as the model drug to load into the hollow spheres. All the spectroscopic results presented showed excellent photophysical parameters of the studied drug. The fabrication of polyelectrolyte hollow spheres can be used as an optimal medium for a variety of bioactive materials, which can also be encapsulated by the proposed method.

The current paper focuses on the issue associated with the biological response of medical grade cobalt chromium (Co–Cr) alloy treated with electrical discharge at different spark energy levels by a varying current, pulse on-time, and pause (off) time. Three types of electrodes, namely, graphite (C), tungsten (W), and copper tungsten (Cu–W) were utilized for treating Co–Cr substrates in two different dielectric media such as mineral oil and deionized water. Electrochemical potentiodynamic tests were performed to investigate the corrosion resistance of untreated and treated surfaces. Furthermore, in vitro hemocompatibility tests were executed on the superior corrosion resistance samples for scrutinizing the red blood cell lysis (human blood response). The study revealed a significant improvement in the corrosion resistivity (<80%) and biological response for the surface treated with W–Cu electrode at low pulse pause duration. X-ray diffraction verified the formation of oxides and phosphides on the treated surface that promotes the biocompatibility.

Three-dimensional (3D) biomimetic scaffolds are critical for tissue engineering to support stem cell culture and organoid formation. Embryonic stem (ES) cells hold promising potential for tissue regeneration and ES cell-derived specific lineages are expected to be strongly influenced by the size of embryoid bodies (EBs). However, the fundamental knowledge needed to achieve the goal of highly reproducible, efficient, and scalable differentiation of how EB size affects differentiation is missing. Here, we used 3D biomimetic scaffolds with highly uniform porous structure to regulate size of EBs and differentiated them toward hepatic fate. The results showed EBs formed within the scaffolds were precisely controlled by pore sizes of the scaffolds. We found that EBs equals to or larger than 180 ± 27 µm maintained the ability to differentiate to hepatic lineage. The 3D biomimetic scaffold provides the effective tools toward accurate regulation of EB sizes for tissue engineering.

Ternary Al–15 wt% Cu–7 wt% Si and Al–22 wt% Cu–7 wt% Si alloy specimens were generated by transient directional solidification (DS) and rapid solidification (RS) techniques. The microstructures are constituted by an α-Al dendritic matrix surrounded by two eutectic, that is, a binary eutectic (Si + α-Al) and a bimodal eutectic, consisting of cellular-type binary eutectic colonies (α-Al + Al2Cu) in a ternary eutectic matrix consisting of α-Al + Al2Cu + Si. The bimodal eutectic exists at cooling rates from 0.5 to 250 K/s. The secondary dendritic spacing, λ2, of the DS samples varied from 5 to 20 μm and from 10 to 18 μm for both examined alloys. The λ2 from 2.7 to 4.0 μm characterized the RS samples. Mechanical properties have been determined for various samples related to different dendritic spacing values. Based on the evaluation of the rapidly solidified microstructures, it was possible to assess the cooling rates.

In this study, a thermal–elastic–plastic finite element model is proposed to investigate the effect of volume energy density on the temperature field, molten pool size, and residual stress distribution in the selective laser melting (SLM) process of Inconel 718 alloy. A temperature-dependent thermal–mechanical property of materials is considered, as well as the properties conversion between powder layer and solidified alloy. Within the scope of the study parameters, the simulated molten pool size increases with increasing volume energy density and exhibits linear growth relationship, which are validated by the experimental results and show a good agreement. In addition, five scanning strategies are adopted to study the effect of these scanning strategies on the residual stress distribution in this research. The results show that the residual stress distribution of SLM Inconel 718 specimen largely depends on the scanning strategy. Finally, to reveal the mechanism of residual stress formation, the restraint bar model is used to further analyze the formation mechanism of residual stress during the SLM process.

GH3536 alloy is one of the high-temperature nickel-based alloys and widely applied in aviation and aerospace industries. In this study, a combination of experiment and simulation is proposed to study the effect of processing parameters on the selective laser melting (SLM) of GH3536 powder. It is concluded that the relationship between density and laser input energy during SLM complies with a quadratic function and presents an inverted U-shaped distribution. By fitting density and input power to a quadratic polynomial, the optimal laser input energy during SLM of GH3536 alloy can be obtained. The result shows that using 275 W laser power and 960 mm/s scanning speed, the SLM GH3536 specimens can reach the maximum density. This experimental result is consistent with the simulation result obtained by analyzing molten pool dimension. Furthermore, a full process energy prediction diagram for SLM GH3536 alloy based on the simulated molten pool depth and width is proposed. The result shows that it provides an innovative and efficient method for the selection of processing parameters during SLM of GH3536 powder.

Process parameters (laser power and scanning speed) for H13 steel specimens produced by selective laser melting (SLM) are optimized, and microstructural characteristics and mechanical properties are investigated. The optimum process parameters are a laser power of 170 W and a scanning speed of 400 mm/s according to the maximum relative density of 99.2%. The microstructure consists of cellular grains and columnar crystal, which are composed of lath martensite and retained austenite, and there are no carbides or other second-phase particles present. The size of cellular grains is 1 μm. Compared with the common processed (forged and heat-treated) H13, SLM H13 has similar microhardness (561 HV) and tensile strength (1909 MPa) values. However, the elongation (12.4%) is a factor of ∼3 times higher and the impact energy (14.4 J) of the SLM specimen is somewhat lower. The relationship between the microstructure and mechanical properties is discussed. Fine grains and no second-phase precipitation determine the strength and plasticity of SLM samples.

In this study, a rapid powder consolidation method combining powder compact hot pressing and extrusion was utilized to consolidate relatively cheap, high impurity blended powder mixture Ti–6Al–4V alloy. The purpose of this work was to investigate whether a suitable microstructure deriving from a particular heat treatment balance out or compensate for the presence of high interstitial impurity contents. From mechanical property data attained, it was clear that annealing in high α–β region gave a much better combination of mechanical properties: impact toughness (14 J), yield strength (878 MPa), ultimate tensile strength (1092 MPa), and ductility/plastic strain (6.2%) compared to as-extruded material despite the presence of 0.44 wt% oxygen. Therefore, it can be concluded that optimization of microstructures provides improvement to the fracture related properties and Ti–6Al–4V produced in this way is suitable for less demanding applications. For further enhancement in properties, utilization of low oxygen starting powders is vital.

Electrochemical treatments, such as electropolishing on titanium alloys, are used to promote the formation of nanostructured surfaces, which can contribute to the bone regeneration process. However, sterilization methods can change the superficial and physicochemical properties of the biomaterials. The objective of this work was to evaluate the effect of three sterilization methods (air plasma, ethanol + PBS, and autoclave sterilizations) on nanostructured Ti6Al4V surfaces properties obtained by electrochemical treatment. These methods, especially the first two, have been widely used in literature, yet few studies in the literature highlight the changes on the surface of the samples. The nanostructures were obtained by electropolishing in a H2SO4/HF/glycerine solution, at 25 V and at 7 °C for 4 min. Samples were characterized by atomic force microscopy (AFM), profilometry, and wettability. Samples were seeded with hESC-MPs, and the cell number was measured. The air plasma sterilization did not promote changes in nanometric morphology and roughness of the Ti6Al4V nanostructured samples. Unlike air plasma sterilization, the ethanol + PBS and the autoclave sterilizations, which strongly affected the nanostructured surface morphology and properties, and, consequently, the cellular viability after 7 days of contact with human embryonic stem cell-derived mesenchymal progenitors (hESC-MPs).