The conventional process for preparing dry spinnable regenerated silk fibroin (RSF) aqueous solution needs not only an addition of Ca2+ but also an adjustment of pH value. In this work, an RSF dry spinning dope was prepared by using a simplified method with solely adding Ca2+. Compared with the conventional RSF solution, the simply prepared aqueous solution showed similar content of β-sheet conformation and diameter of RSF aggregates but lower viscosity. Furthermore, the posttreated RSF fiber dry-spun from this simply prepared solution showed higher crystallinity and crystalline orientation, smaller crystallite size, and better mechanical properties. It could be concluded that Ca2+ played a much more important role than pH value in improving the structures and properties of RSF spinning solution and fibers. Therefore, the step of adjusting pH value could be excluded in the process of preparing high performance RSF fibers.

The fast dissolution of certain calcium-containing compounds makes them attractive carriers for trace minerals in nutritional applications, e.g., iron and zinc to alleviate mineral deficiencies in affected people. Here, CaO-based nanostructured mixed oxides containing nutritionally relevant amounts of Fe, Zn, Cu, and Mn were produced by one-step flame spray pyrolysis. The compounds were characterized by nitrogen adsorption, x-ray diffraction, (scanning) transmission electron microscopy, and thermogravimetric analysis. Dissolution in dilute acid (i.d.a.) was measured as an indicator of their in vivo bioavailability. High contents of calcium resulted in matrix encapsulation of iron and zinc preventing formation of poorly soluble oxides. For 3.6 ≤ Ca:Fe ≤ 10.8, Ca2Fe2O5 coexisted with CaO. For Ca/Zn compounds, no mixed oxides were obtained, indicating that the Ca/Zn composition can be tuned without affecting their solubility i.d.a. Aging under ambient conditions up to 225 days transformed CaO to CaCO3 without affecting iron solubility i.d.a. Furthermore, Cu and Mn could be readily incorporated in the nanostructured CaO matrix. All such compounds dissolved rapidly and completely i.d.a., suggesting good in vivo bioavailability.

In the present study, aminofunctionalized mesoporous silica (AFMS) was synthesized using the anionic surfactant N-lauroylsarcosine sodium as template and 3-aminopropyltrimethoxysilane as costructure directing agent. The synthesized mesoporous silica was characterized by the Fourier transform infrared spectra, x-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy techniques. The application for the removal of Ni2+ from aqueous solution using the synthesized mesoporous silica as adsorbent was investigated. It was found that the solution pH affected adsorption of Ni2+ greatly. The kinetic data of adsorption showed that the removal rate of Ni2+ was substantially high. The adsorption isotherms were fitted using the Sips, Langmuir, and Freundlich models, respectively, and the results showed that the Sips model was the best one to describe the experimental data. From the data of Sips, the maximum adsorption capacity of Ni2+ in respect of the extracted sample is 2.48 mmol/g, much higher than those reported in other literature. The possible adsorption mechanism of Ni2+ on the AFMS was proposed.

Microstructures and mechanical properties of the Mg–4Y–2.5Nd–0.6Zr (wt%) alloy in the as-cast, as-rolled, and rolled-T5 conditions have been investigated. Results showed that the as-cast sample mainly consisted of the α-Mg matrix, network-like Mg41Nd5 phase, and cuboid-shaped Mg24Y5 particles. For the as-rolled sample, the thermally stable Mg24Y5 particles located at both grain boundaries and matrix, and the average grain size was greatly refined to about 15 μm. Yield strength, ultimate tensile strength, and elongation of as-rolled samples were 290 MPa, 235 MPa, and 10%, respectively. They were enhanced by 48.7%, 56.7%, and 38.9% correspondingly compared with those of the as-cast sample. After isothermal aging at 250 °C for 4 h, the optimal mechanical properties can be obtained. Besides, the tensile strengths of as-rolled and rolled-T5 samples decreased gradually with a gradual increase of ductility from room temperature to 300 °C. Quasicleavage and cleavage fracture were the fracture patterns of as-rolled and rolled-T5 samples, respectively, at room temperature. For samples under the two conditions, fracture mode similarly changed with the increase of test temperatures, and ductile fracture can be observed at higher temperature.

Exceptionally dense titanium dioxide (TiO2) films were prepared via dip coating from a sol containing poly(hexafluorobutyl methacrylate) as the structure-directing agent. The films were grown on glass, F-doped SnO2, and crystalline silicon (111) faces, either pure or with a thin layer of SiO2. The TiO2 films cover perfectly even rough surfaces, which was ascribed to thixotropic properties of the precursor gel. The films provide antireflection function to crystalline Si wafers for photovoltaic applications. The optical reflectance in visible to near-infrared (NIR) wave lengths region is considerably smaller for Si wafers covered by TiO2/SiO2 film compared with that of SiO2/Si. The dense TiO2 films are amorphous with small amount of anatase and monoclinic TiO2(B). These two phases withstand calcination at 900 °C in films deposited on Si. For comparison, porous TiO2 films were grown by the same dip-coating protocol, but with alternative organic additives, either polymers or ionic liquids.

Optimization of the pore topology in organosilicate glass (OSG) is crucial in the development of dielectrics with an extremely low k-value and a relatively high Young’s modulus. In this paper, a finite-element modeling strategy is applied to develop a general understanding of the relationship between porosity, pore topology, and elastic modulus for the porous OSG thin films. This relationship in combination with the experimental elastic modulus data from nanoindentation (NI) studies is used to predict the pore structure of various OSG films. In addition, positron annihilation spectroscopy measurements are performed to determine the threshold porosity for the transition from nonoverlapping to overlapping porous structure. A similar threshold value is determined based on the finite-element modeling and experimental NI data.

Copper (I) oxide (Cu2O) is a direct band gap semiconductor with p-type conductivity and is a potential candidate for multi-junction solar cells. In this work, incoherent light source based photo-assisted metal-organic chemical vapor deposition (MOCVD) was used to deposit high quality Cu2O thin films on n-type <100> silicon and quartz substrates. X-ray diffraction studies reveal that crystalline Cu2O is deposited. UV-Vis-NIR spectroscopy results indicated a band gap of 2.44 eV for Cu2O thin films. Transmission electron spectroscopy results show that the Cu2O film grows in the form of three-dimensional islands composed of smaller nanocrystalline grains in the range of 10–20 nm. I–V measurements indicate that the Cu2O/n-Si device fabricated using the MOCVD process has a lower dark current density than other devices reported in the literature.

The liquid impingement erosion behavior of a zirconium-based bulk metallic glass (BMG), Zr44Ti11Cu10Ni10Be25, was evaluated in this study. For comparison, commonly used hydroturbine steel was evaluated under the same test conditions. BMG demonstrated more than four times higher resistance against cavitation erosion compared with hydroturbine steel. The unusually high erosion resistance for BMG is attributed to its uniform amorphous structure with no grain boundaries, higher hardness, and ability to accommodate strain through localized shear bands.

A kinetics model for the precipitation of M23C6 in high Cr ferritic heat resistant steel during tempering has been developed assuming the site-saturated nucleation, carbon diffusion-controlled growth and soft-impingement. The growth coefficient in this model is temperature-dependent, and the Arrhenius equation is applied to describe the growth coefficient, in which the growth activation energy is nearly equal to the diffusion activation energy of carbon in martensite. The effect of main parameters in this model has been discussed in detail. By this model, the precipitation of M23C6 during tempering can be predicted accurately in the case of 2D, and a good agreement with experimental data in previous work has been achieved.

The objective of this work is to reveal the relationship between the molecular structure and shape-memory property of a hydro-epoxy resin system. The system is prepared using hydro-epoxy, menthane diamine (MDA), and poly(propylene glycol) diglycidyl ether (PPGDGE) with different molecular weights. By keeping the PPGDGE content constant, the crosslink density of the shape-memory hydro-epoxy resin system can be changed by varying the molecular weight of PPGDGE. The results indicate that the glass transition temperature (Tg) and rubber modulus (Er) decrease as the crosslink density decreases. The crosslink density has little influence on shape recovery ratio (Rr). Full recovery can be observed after only several minutes when the temperature is equal to or above Tg. However, the crosslink density has a profound effect on the shape fixity ratio (Rf). If the crosslink density is too low, the shape fixity ratio of shape-memory hydro-epoxy resin would not reach 100%.

In this article we develop an analytical theory that correlates the macroscopic curvature of stressed film/substrate systems with the microscopic in-plane and out-of-plane deflections of planar rotators. We have extended these stress-deflection relations in the case of nonlinear stress fields and validated the results with the aid of finite element simulations. We use this theory to study the heteroepitaxial growth of cubic silicon carbide on silicon (100) and discovered that, due to defects generated on the silicon substrate during the carbonization process, wafer curvature techniques alone may not enable determination of the stress field in the grown films either quantitatively or qualitatively.