Energy conversion from heat to electricity by highly reversible phase-transforming ferroelectrics

Searching for performant multiferroic materials attracts general research interests in energy science as they have been increasingly exploited as the conversion media among thermal, electric, magnetic and mechanical energies by using their temperature-dependent ferroic properties. Here we report a material development strategy that guides us to discover a reversible phase-transforming ferroelectric material exhibiting enduring energy harvesting from small temperature differences. The material satisfies the crystallographic compatibility condition between polar and nonpolar phases, which shows only 2.5C thermal hysteresis and high figure of merit. It stably generates 15uA electricity in consecutive thermodynamic cycles in absence of any bias fields. We demonstrate our device to consistently generate 6uA/cm2 current density near 100C over 540 complete phase transformation cycles without any electric and functional degradation. The energy conversion device can light up a LED directly without attaching an external power source. This promising material candidate brings the low-grade waste heat harvesting closer to a practical realization, e.g. small temperature fluctuations around the water boiling point can be considered as a clean energy source.Comment: 21 pages, 9 figures, 2 table

Analysis on Colonization Dynamics and Phosphate Solubilization Effects of a Penicillium Strain in Soil

【Objective】The colonization dynamics and phosphate solubilization effects of Penicillium brocae in soil were studied in order to provide references for the development and application of soil phosphate solubilization bioinoculant, .【Method】A P. brocae transformant Z3 with multiple molecular screening makers was used for soil cultivation test. Combining with the screening makers, the colony forming units (CFU) of Z3 in soil were quantified with plate counting method at different time nodes and the soil available phosphate (AP) was measured at the same time.【Result】The green fluorescent protein (gfp), hygromycin B phosphotransferase (hph) and β-glucuronidase (gus) genes could expressed normally in Z3, and there was no significant difference in the growth curve and phosphate solubilization ability between Z3 and wild type (Wt) strain. The colonization number of Z3 in soil decreased from 1×106 CFU/g to 1×105 CFU/g at the first stage, then it increased to the maximum value of 4.3×106 CFU/g at the third week and followed by a gradually decreasing to 1.4×103 CFU/g in soil at the tenth week. The soil AP content showed a trend of increasing first and then decreasing. At the sixth week, the soil AP reached the maximum value of 14.7 mg/L which increased by 41.3% compared to the AP of original soil. After inoculation for seven weeks, the soli AP gradually decreased to 12.7 mg/L at the tenth week which still increased by 22.1% compared to the AP of original soil. Additionally, it was also found that the colonization number of Z3 in soil were close to or higher than 1×105 CFU/g during the increasing of soil AP and the AP gradually decreased when the number of Z3 was significantly lower than 1×105 CFU/g.【Conclusion】The transformant Z3 can well colonize for ten weeks after being inoculated into soil, which shows good colonization ability and increases soil AP concentration significantly. Additionally, the colonization number of Z3 has a positive role in the maintenance of phosphate solubilization effects

Two-Tier Compatibility of Superelastic Bicrystal Micropillar at Grain Boundary.

Both crystallographic compatibility and grain engineering are super critical to the functionality of shape memory alloys, especially at micro- and nanoscales. Here, we report a bicrystal CuAl24Mn9 micropillar engraved at a high-angle grain boundary (GB) that exhibits enhanced reversibility under very demanding driving stress (about 600 MPa) over 10 000 transformation cycles despite its lattice parameters are far from satisfying any crystallographic compatibility conditions. We propose a new compatibility criterion regarding the GB for textured shape memory alloys, which suggests that the formation of GB compatible twin laminates in neighboring textured grains activates an interlock mechanism, which prevents dislocations from slipping across GB