Half-Heusler-like compounds with wide continuous compositions and tunable p- to n-type semiconducting thermoelectrics

Half-Heusler and full-Heusler compounds were considered as independent phases with a natural composition gap. Here we report the discovery of TiRu1+xSb (x = 0.15 ~ 1.0) solid solution with wide homogeneity range and tunable p- to n-type semiconducting thermoelectrics, which bridges the composition gap between half- and full-Heusler phases. At the high-Ru end, strange glass-like thermal transport behavior with unusually low lattice thermal conductivity (~1.65 Wm−1K−1 at 340 K) is observed for TiRu1.8Sb, being the lowest among reported half-Heusler phases. In the composition range of 0.15 < x < 0.50, TiRu1+xSb shows abnormal semiconducting behaviors because tunning Ru composition results in band structure change and carrier-type variation simultaneously, which seemingly correlates with the localized d electrons. This work reveals the possibility of designing fascinating half-Heusler-like materials by manipulating the tetrahedral site occupancy, and also demonstrates the potential of tuning crystal and electronic structures simultaneously to realize intriguing physical properties.

Study on Low-Frequency Abnormal Signal and Structural Characteristics of 2015 Azuoqi Ms5.8 Earthquake

In this article, the phenomenon of low-frequency abnormal signals before earthquakes, which reflects the three elements of earthquakes and the beneath structure change information, is discussed. Based on the data recorded at the Shizuishan (SZS), Wuhai (WUH) and Dongshenmiao seismic stations around the epicenter of the Ms5.8 earthquake in Azuoqi, Inner Mongolia, in 2015, the low-frequency abnormal signal from the seismic waves before this earthquake is extracted. At the same time, the autocorrelation method is used to extract the reflected waves of the main interface from teleseismic events recorded by the seismic array in the epicenter area, and then the change information from the beneath structure is obtained. It is explained in time and space that the low-frequency abnormal signal before the main earthquake, extracted from the continuous waveform, is directly related to the change in the underground structure near the epicenter, and it can be determined that the wave propagation direction f the crustal stress before the earthquake is from south to north, and it continues to accumulate near the epicenter until the main earthquake occurs.

Production and characterization of bacterial cellulose-alginate biocomposites as food packaging material

Biocomposite of bacterial cellulose-alginate has been developed for use as food packaging material. This study aims to understand the physical and mechanical properties of the biocomposite produced from static fermentation of Gluconacetobacter xylinus InaCC B404 in media supplemented with alginate. The strain was grown in a medium containing alginate at a concentration of 0.4, 0.8, and 1.2% w/v at 30oC for 7 days. The SEM images showed that bacterial cellulose produced in a medium supplemented with alginate had a denser structure of fibril network and a smaller pore size than the control one. The structure change was due to interactions through hydrogen bonds between bacterial cellulose and alginate proven by FTIR spectra, resulting in a decrease in crystallinity and crystallite size of bacterial cellulose. It led to the decrease in tensile and tear strength of the resulting biocomposite. Alginate also causes biocomposite to have higher water vapour permeability values.

Crystal structure change in multilayer GeH flakes by hydrogen desorption under ultrahigh vacuum environments

To confirm the feasibility of the theoretically proposed method of forming free-standing germanene [Araidai et al., J. Appl. Phys. 128, 125301 (2020).], we have experimentally investigated hydrogen desorption properties from the hydrogen-terminated germanane (GeH) flakes. Thermal desorption spectroscopy analysis revealed that hydrogen desorption occurred during the heating under an ultrahigh vacuum environment, corresponding to mass loss of 1.0 wt%. Moreover, we have found that using an ultrahigh vacuum ambient and short-time annealing for hydrogen desorption is a key to sustain the crystal structures.

The Robustness of Synthetic Observations in Producing Observed Core Properties: Predictions for the TolTEC Clouds to Cores Legacy Survey

We use hydrodynamical simulations of star-forming gas with stellar feedback and sink particles—proxies for young stellar objects (YSOs)—to produce and analyze synthetic 1.1 mm continuum observations at different distances (150–1000 pc) and ages (0.49–1.27 Myr). We characterize how the inferred core properties, including mass, size, and clustering with respect to diffuse natal gas structure, change with distance, cloud evolution, and the presence of YSOs. We find that atmospheric filtering and core segmentation treatments have distance-dependent impacts on the resulting core properties for d < 300 pc and 500 pc, respectively, which dominate over evolutionary differences. Concentrating on synthetic observations at further distances (650–1000 pc), we find a growing separation between the inferred sizes and masses of cores with and without YSOs in the simulations, which is not seen in recent observations of the Monoceros R2 (Mon R2) cloud at 860 pc. We find that the synthetic cores cluster in smaller groups, and that their mass densities are correlated with gas column density over a much narrower range, than those in the Mon R2 observations. Such differences limit the applicability of the evolutionary predictions we report here, but will motivate our future efforts to adapt our synthetic observation and analysis framework to next generation simulations, such as Star Formation in Gaseous Environments (STARFORGE). These predictions and systematic characterizations will help to guide the analysis of cores on the upcoming TolTEC Clouds to Cores Legacy Survey on the Large Millimeter Telescope Alfonso Serrano.