DETERMINATION AND MODELING OF THE LIQUIDUS SURFACE, VAPOR PRESSURE AND IMMISCIBILITY BOUNDARIES IN THE Cu–Pb–S SYSTEM

For the first time using a membrane zero-manometer, the vapor pressure S2 over the surface of the PbS liquidus in the ternary system Cu–Pb–S were determined in the range 1100÷1400 K and 0÷760 mm Hg. Based on the thermodynamic calculation, the boundaries of the immiscibility of liquid alloys of the Cu–S, Pb–S, and Cu–Pb–S systems were determined and analytically described. Critical temperatures and pressures for immiscibility regions of sulfur-rich liquid alloys are characterized by high values: Tcr= 1520÷1880 K; Pcr=170÷510 atm. The crystallization surfaces of lead sulfide with electronic conductivity (p-type PbS) and with hole conductivity (n-type PbS) are calculated and analytically de-scribed, as well as the corresponding values of sulfur vapor pressure over the crystallization surface of lead sulfide. All analytical dependencies for 3D modeling were obtained and visualized using the OriginLab computer program

Shaping and properties of thermoplastic scaffolds in tissue regeneration: The effect of thermal history on polymer crystallization, surface characteristics and cell fate

Thermoplastic semi-crystalline polymers are excellent candidates for tissue engineering scaffolds thanks to facile processing and tunable properties, employed in melt-based additive manufacturing. Control of crystallization and ultimate crystallinity during processing affect properties like surface stiffness and roughness. These in turn influence cell attachment, proliferation and differentiation. Surface stiffness and roughness are intertwined via crystallinity, but never studied independently. The targeted stiffness range is besides difficult to realize for a single thermoplastic. Via correlation of thermal history, crystallization and ultimate crystallinity of vitamin E plasticized poly(lactide), surface stiffness and roughness are decoupled, disclosing a range of surface mechanics of biological interest. In osteogenic environment, human mesenchymal stromal cells were more responsive to surface roughness than to surface stiffness. Cells were particularly influenced by overall crystal size distribution, not by average roughness. Absence of mold-imposed boundary constrains makes additive manufacturing ideal to spatially control crystallization and henceforward surface roughness of semi-crystalline thermoplastics. Graphic abstract

Preparation and Characterization of Sulfated TiO2/Zeolite Composite Catalysts with Enhanced Photocatalytic Activity

Sulfated TiO2 nanoparticles were successfully immobilized on zeolite through improving hydrolysis-deposition method. Microstructure, crystallization, surface state and surface area of composite catalysts were characterized by SEM, XRD, FTIR spectra, XPS and BET and the photocatalytic activity was evaluated by degradation of methyl orange under UV irradiation. We optimized these factors (SO[Formula: see text] ions, calcination temperature and loading amount of sulfated TiO[Formula: see text] on photocatalytic activity and crystallization of composite photocatalysts. The results indicated that the SO[Formula: see text] ions are successfully immobilized on the surface of TiO2, and sulfated TiO2/zeolite show the highest photocatalytic activity for methyl orange at the [SO[Formula: see text]]/[Ti[Formula: see text]] molar rate of 1:1, calcination temperature of 600[Formula: see text]C for 2[Formula: see text]h, and sulfated TiO2 loading amount of 40%, respectively.

Thermally Stable Two-Dimensional Photonic Crystal for Selective Emitters

ABSTRACTA fundamental challenge in solar-thermal-electrical energy conversion is the thermal stability of materials and devices at high operational temperatures. This study focuses on the thermal stability of selective emitters for solar thermophotovoltaic (STPV) systems to enhance the conversion efficiency. 2-D photonic crystals are periodic micro/nano-scale structures that are designed to affect the motion of photons at certain wavelengths. The structured patterns, however, lose their structural integrity at high temperature, which disrupts the tight tolerances required for spectral control of the thermal emitters. Through analytical studies and experimental observations, the four major mechanisms of thermal degradation of 2-D photonic crystal are identified: oxidation, grain growth and re-crystallization, surface diffusion, and evaporation and re-condensation. In this work, the design of a flat surface photonic crystal (FSPC) is proposed and experimental validations are performed.

Ferroelectric and Physical Characteristic of the La and V Doped on Bi4Ti3O12 Thin Film Prepared by RF Magnetron Sputtering Method

In this study, the effects of La and V doping on Bi4Ti3O12(BLTV) ferroelectric thin films deposited on ITO/glass substrates using rf magnetron sputtering were produced and investigated. The effect of oxygen concentration and RF power on the physical and electrical characteristics of BLTV thin films was determined. The physical characteristics of BLTV thin films were obtained by the XRD pattern, SEM and AFM. The variations of crystallization, surface roughness and thickness of BLTV thin films were discussed. The electrical properties of BLTV thin films deposited under various parameters were measured by the HP4156C.

Facile Preparation and Photoinduced Superhydrophilicity of Highly Ordered Sodium-Free Titanate Nanotube Films by Electrophoretic Deposition

Highly ordered sodium-free titanate nanotube films were one-step prepared on F-doped SnO2-coated (FTO) glass via an electrophoretic deposition method by using sodium titanate nanotubes as the precursor. It was found that the self-assembled formation of highly ordered sodium titanate nanotube films was accompanied with the effective removal of sodium ions in the nanotubes during the electrophoretic deposition process, resulting in the final formation of protonated titanate nanotube film. With increasing calcination temperature, the amorphous TiO2phase is formed by a dehydration process of the protonated titanate nanotubes at 300°C and further transforms into anatase TiO2when the calcination temperature is higher than 400°C. Compared with the as-prepared titanate nanotube film, the calcined titanate nanotube film (300–600°C) exhibits attractive photoinduced superhydrophilicity under UV-light irradiation. In particular, 500°C-calcined films show the best photoinduced superhydrophilicity, probably due to synergetic effects of enhanced crystallization, surface roughness, and ordered structures of the films.

Characterization of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si Titanium Alloy by Laser Shock Peening

In this paper, the microstructure and microhardness of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si titanium alloy with and without laser shock peening (LSP) were examined and compared. The titanium alloy samples were treated with different layers, at the same power density. X-ray diffraction (XRD), Transmission Electron Microscope (TEM) and microhardness techniques were used to analyse microstructure and mechanical. X-ray diffraction analysis shows that there was not any phase transformation and no new crystalline phases have been formed. TEM studies demonstrate that both α and β phase can been refined in the surface layer with LSP. The microhardness measurements with LSP demonstrate that Hardness of crystallization surface is high up to 418MPa, which is more than the sample without LSP, the shock wave improved the microhardness for about 8%, and the affected depth is about 400 microns from the surface.