High Thermoelectric Performance Achieved in Sb-Doped GeTe by Manipulating Carrier Concentration and Nanoscale Twin Grains

Lead-free and eco-friendly GeTe shows promising mid-temperature thermoelectric applications. However, a low Seebeck coefficient due to its intrinsically high hole concentration induced by Ge vacancies, and a relatively high thermal conductivity result in inferior thermoelectric performance in pristine GeTe. Extrinsic dopants such as Sb, Bi, and Y could play a crucial role in regulating the hole concentration of GeTe because of their different valence states as cations and high solubility in GeTe. Here we investigate the thermoelectric performance of GeTe upon Sb doping, and demonstrate a high maximum zT value up to 1.88 in Ge0.90Sb0.10Te as a result of the significant suppression in thermal conductivity while maintaining a high power factor. The maintained high power factor is due to the markable enhancement in the Seebeck coefficient, which could be attributed to the significant suppression of hole concentration and the valence band convergence upon Sb doping, while the low thermal conductivity stems from the suppression of electronic thermal conductivity due to the increase in electrical resistivity and the lowering of lattice thermal conductivity through strengthening the phonon scattering by lattice distortion, dislocations, and twin boundaries. The excellent thermoelectric performance of Ge0.90Sb0.10Te shows good reproducibility and thermal stability. This work confirms that Ge0.90Sb0.10Te is a superior thermoelectric material for practical application.

Mirror Diffusion of Cosmic Rays in Highly Compressible Turbulence Near Supernova Remnants

Recent gamma-ray observations have revealed inhomogeneous diffusion of cosmic rays (CRs) in the interstellar medium (ISM). This is expected, as the diffusion of CRs depends on the properties of turbulence, which can vary widely in the multiphase ISM. We focus on the mirror diffusion arising in highly compressible turbulence in molecular clouds (MCs) around supernova remnants (SNRs), where the magnetic mirroring effect results in significant suppression of diffusion of CRs near CR sources. Significant energy loss via proton–proton interactions due to slow diffusion flattens the low-energy CR spectrum, while the high-energy CR spectrum is steepened due to the strong dependence of mirror diffusion on CR energy. The resulting broken power-law spectrum of CRs matches well the gamma-ray spectrum observed from SNR/MC systems, e.g., IC443 and W44.

Break events of the western North Pacific summer monsoon during 1979–2018

The monsoon break is a typical phenomenon representing the monsoon’s subseasonal variability, but its understanding is still limited for the western North Pacific (WNP) area. This study identified all break events of the WNP summer monsoon (WNPSM) from 1979 to 2018. The statistical analysis suggests that break events occur from late June to late October and peak at the end of August. The occurrence frequency of break events decreases as the duration increases, with 74% persisting 3–7 days and merely 26% lasting longer (8–15 days). During the break period, which is characterized by significant suppression of convection, there is an extensive anticyclonic anomaly in the lower troposphere, corresponding to a notable westward retreat of the monsoon trough and a southwestward shift of the subtropical high. Meanwhile, an anomalous cyclone and convergence in the upper troposphere are also conducive to inhibiting convection.The composite results indicate that both 10–25-day and 30–60-day oscillations contribute to the break, with their dry phases explaining 49.6% and 37.5% of the original suppression of convection, respectively. Around the break, the phase alternation of the 10–25-day oscillation causes convection fluctuation, while the 30–60-day oscillation maintains a stable dry phase that favors the establishment and maintenance of the break. A further case-by-case diagnosis suggests that 46 (51) out of the 61 break events occur in dry phases of the 10–25-day (30–60-day) oscillation, while only 10 (4) events occur in wet phases, indicating that the phase of the two oscillations significantly modulates the occurrence of the monsoon break.

In Vitro Evaluation of Bacterial Bioagents and Fungicides Efficiency against Rhizoctonia solani Isolates the Causal agent of Black Scurf Disease of Potato

The efficacy of two isolates of bacterial bioagents and two fungicides via, Rhizoctonia solani isolates were evaluated in vitro. In the dual culture assays, significance inhibition ratio of R. solani hyphal growth was obtained in all treatments of Pesudomonas fluoresnces and Bacillis subtilis compared to control. Also, Bacillus subtilis exhibit the highest significant suppression for the mycelial growth of R. solani isolates more than Pseudemonas fluorescens, and the ratios of inhibition differed according to the bioagents and R. solani isolates similar to those results in antifungal activity technique. The volatile metabolite studies revealed that in the first period (three days) inhibition percentage significantly differed according to the tested isolates of R. solani and the applied bioagents, B. subtilis gave the highest inhibition (57.41%) in R. solani isolate 3. Similarly in P. fluoresnces treatments, the highest inhibition was (57.41%) was detected in isolate 3 of R. solani considering that the second tested time period (five day inoculation). B. subtilis showed highest inhibition value on isolate 1, on the other hand P. flouresnce showed high value of inhibition on isolate 2, whereas the lowest inhibition values were produced on isolate 1.Non volatile activity both bacterial bioagents isolates showed different values of inhibition on R. solani isolates. On the other hand Rezolex was most effective against R. solani at two concentrations (0.2 and 0.3), however Topsin-M showed fluctuate inhibition values at two concentration used (0.04% and 0.075%). Further incubation of plates showed suppressed the formation of sclerotia by all the antagonists tested. The results implied that the extent of inhibition by B. subtilis and P. fluoresnces rovides the use of excellent potential antagonists capable of controlling the R. solani in vitro.

High Thermoelectric Performance Achieved in Sb-doped GeTe by Manipulating Carrier Concentration and Nanoscale Twin Grains

Lead-free and eco-friendly GeTe shows a promising candidate for mid-temperature thermoelectric application. However, a low Seebeck coefficient due to its intrinsically high holes concentration that induced by Ge vacancies, and a relatively high thermal conductivity result in an inferior thermoelectric performance of pristine GeTe. However, extrinsic atoms Sb, Bi, and Y could play a crucial role in regulating the holes concentration of GeTe because of their relatively high solubility. Here we investigate the thermoelectric performance of the GeTe upon Sb doping, and demonstrate a high maximum zT value up to 1.88 could be achieved in Ge 0.90 Sb 0.10 Te as a result of the significant suppression in thermal conductivity while holding a high power factor. Where the maintained high power factor is due to the markable enhancement in S , which could be attributed to the significant suppression of holes concentration and the valence band convergence upon Sb doping; while the low thermal conductivity stems from the suppression of electronic thermal conductivity due to the increase in electrical resistivity and the lowering of lattice thermal conductivity through strengthening the phonons scattering by the lattice distortion, dislocations, and twin boundaries. Aside from the excellent thermoelectric performance, Ge 0.90 Sb 0.10 Te also shows good reproducibility, as well as thermal stability. This work confirms the Ge 0.90 Sb 0.10 Te is a superior thermoelectric material for practical application.

A single serving of mixed spices alters gut microflora composition: a dose–response randomised trial

Short-term changes in dietary intake can induce changes in gut microbiome. While various dietary polyphenols have been shown to modulate gut microflora, the acute influence of polyphenol-rich mixed spices has not been explored in a controlled setting. We investigated the effects of a single serving of mixed spices Indian curry consumption, in two separate doses, on the gut microbiome in 15 healthy, Singaporean Chinese males, with age and BMI of 23.5 ± 2.4 years and 22.9 ± 2.2 kg/m2 respectively. We found that a low-polyphenol, no spices Dose 0 Control (D0C) meal led to an increase in Bacteroides and a decrease in Bifidobacterium. In comparison to D0C, there was significant suppression of Bacteroides (p < 0.05) and an increase in Bifidobacterium (p < 0.05) with increasing doses of curry meal Dose 1 Curry (D1C) and Dose 2 Curry (D2C) containing 6 g and 12 g mixed spices respectively. Significant correlations were also found between bacterial changes and plasma phenolic acids. No differences between treatments were observed in the alpha-diversity of the gut microflora. This study has shown that a single serving of mixed spices can significantly modify/restore certain commensal microbes, particularly in people who do not regularly consume these spices.