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Arthrospira platensis has attracted wide attention as a cyanobacteria with high nutritional value. In this research, the response surface method was used to study the effects of light cycle, light intensity and red-blue LED conditions on the growth and organic matter accumulation in spiral shaped strain A. platensis OUC623 and linear shaped strain A. platensis OUC793. The light conditions suitable for A. platensis OUC623 were as follows: growth (light time 12.01 h, light intensity 35.64 μmol/m2s, LED red: blue = 6.38:1); chlorophyll a (light time 12.75 h, light intensity 31.06 μmol/m2s, red: blue = 6.25:1); carotenoid (light time 13.12 h, light intensity 32.25 μmol/m2s, red: blue = 5.79:1); polysaccharide (light time 16.00 h, light intensity 31.32 μmol/m2s, blue: red = 6.24:1); protein (light time 12.18 h, light intensity 6.12 μmol/m2s, blue: red = 7.95:1); phycocyanin (light time12.00 h, light intensity 5.00 μmol/m2s, blue: red = 8.00:1). The light conditions suitable for A. platensis OUC793 were as follows: growth (light time 13.52 h, light intensity 40.22 μmol/m2s, red: blue = 5.98:1); chlorophyll a (light time 14.22 h, light intensity 44.96 μmol/m2s, red: blue = 5.94:1); carotenoid (light time 14.13 h, light intensity 44.50 μmol/m2s, red: blue = 6.02:1); polysaccharide (light time 16.00 h, light intensity 31.85 μmol/m2s, blue: red = 6.08:1); protein (light time12.00 h, light intensity 5.00 μmol/m2s, blue: red = 8.00:1); phycocyanin (light time12.01 h, light intensity 5.01 μmol/m2s, blue: red = 8.00:1). Under the theoretical optimal light conditions, compared with white LED, the growth rate, chlorophyll a, carotenoid, phycocyanin, protein and polysaccharide contents in strain 623 increased by 91.67%, 114.70%, 85.05%, 563.54%, 386.14%, 201.18%, and in strain 793 increased by 75.00%, 150.94%, 113.43%, 427.09%, 1284.71%, 312.38%, respectively. The two strains showed different advantages. Growth rate, chlorophyll a, polysaccharide, protein and phycocyanin content of strain 623 were higher than those of strain 793, while carotenoid was higher in strain 793. After optimization, both strains could reach a good growth state, and the growth rate and organic matter content were close. And then a 20 L photobioreactor was used to expand the culture of the two strains, validating the theoretical optimal light conditions of response surface method. This study laid the foundation for the establishment of optical conditions for organic matter accumulation in two different strains of A. platensis, which provided more options for meeting the industrialization needs of A. platensis.

Polycrystalline Ni-Mn-Ga-Fe fibers were prepared by melt-extraction technique. The internal stress and defects introduced by rapid solidification were modified by step-wise chemical ordering annealing. The microstructure and phase microstructure of fibers were characterized using Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscopy (TEM) and XRD diffraction technique. The phase transition behavior and two-way shape memory effect (TWSME) were tested using Dynamic Mechanical Analyzer (DMA). The results show that after heat treatment, the chemical ordering degree is increased, and the martensite twin boundaries are straight. Complete recoverable strains of parent and martensite phases during thermal cycles are achieved. During the two-way shape memory cycles, two characteristics of thermoelastic martensite transition are displayed in heat-treated fibers: reversibility and thermal hysteresis. In the thermal cycle test, the total strain reaches 1.32% when the fiber is loaded to 198 MPa. The thermomechanical tensile measurement shows that the phase transition temperature follows the Clausius-Clapeyron equation. Compared with other alloys such as Ti-Ni and Cu-Al-Ni, Fe-doped fiber exhibits a smaller strain-stress dependence, which is beneficial to the constant strain output.

An analytical approach was developed to investigate nucleation and growth of Ti-48Al (atom fraction/%) alloy droplets during their flight in an argon atomization process. Evolution of microstructure of the solidified powders was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and electron back-scatter diffraction (EBSD). Newton cooling model based on the initial number of nuclei, liquid/solid interface velocity, cooling rate and size of droplets was established. The results show that statistical nucleation events increase exponentially with the increase of powders size, and the growth of nuclei is transformed from a twinned spherical segment into a concentric liquid/solid interface geometry. Temperature of atomized droplets decreases rapidly with the cooling rate of 105-106K·s-1.Then temperature increases sharply to near the liquidus temperature during recalescence. When the recalescence is completed, the droplet solidifies at a relatively slower rate. Afterwards the cooling rate of the fully solid phase decreases to about 105K·s-1.

Exploring highly efficient oxygen evolution reaction (OER) electrocatalysts is important for industrial water electrolysis, especially under high current densities (>1 A cm−2). High‐entropy alloy (HEA) with high surface OER activity and excellent electrical conductivity of the core is an ideal route to improve the catalytic activity. Herein, a combined theoretical and experimental approach to establish core–shell FeCoNiMoAl‐based HEA as a promising OER electrocatalyst is presented. Theoretical calculations combined with structure analyses indicate crystalline–amorphous (c–a) heterostructure of shell reduces the electron transfer resistance and generates more active sites, furthermore the crystalline core improves the conductivity and self‐supporting ability. HEA electrodes demonstrate superior OER performance with an overpotential (η) of 470 mV at 2 A cm−2 and no apparent degradation even after 330 h of continuous testing, notably, for overall water splitting the stability is more than 120 h at 2.06 V. The special core–shell structure achieves a win–win strategy for high OER activity and stability. These findings shed light on the structural design of HEA electrocatalysts and present a promising route to achieve highly efficient electrocatalysts for industrial water electrolysis and relevant energy conversion processes. [ABSTRACT FROM AUTHOR]

Due to its dual gas- and liquid-like properties, supercritical carbon dioxide (scCO2) is considered an excellent solvent for dissolving precursors and penetrating nanoscale pores. After subsequent calcination, uniformly dispersed metal or metal oxide nanoparticles or nanowires can be obtained. Organometallic salts are commonly used precursors in this method because they usually have high solubility in scCO2. Therefore, solubility data are essential for the controllable synthesis of such nanocomposites. This work establishes a facile and accessible method for measuring the solubility of organic solids in scCO2. The solubilities of copper acetylacetonate and cobalt acetylacetonate were obtained at temperatures of 313–333 K and pressures of 11–24 MPa. And the solubilities were within 2.3 × 10−2 to 14.1 × 10−2 g/L for Cu(acac)2 and 6.9 × 10−2 to 13.4 × 10−2 g/L for Co(acac)2. The experimental data were fitted to the semi-empirical model with the AARD values of 4.58% and 2.14% for Cu(acac)2 and Co(acac)2, respectively, and the obtained equations could be used to predict solubility of the same systems in the experimental range. [ABSTRACT FROM AUTHOR]