ALBERT

Description: 〈span〉〈div〉ABSTRACT〈/div〉Determining how faults behave during large earthquakes can help provide insight into the mechanism of regional tectonism. Here, we use Advanced Land Observing Satellite‐2 (ALOS‐2) and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) data to estimate the source parameters of the 2017 Mw 6.6 Poso earthquake, eastern Indonesia. The results show that the coseismic rupture was predominated by normal faulting at depths of 3–10 km, whereas some distinct dextral strike slip is also resolved along the down‐dip direction of normal‐faulting zones. We analyze the background seismicity, regional topography, and fault kinematics to investigate the present‐day tectonics of central Sulawesi as well as its evolutionary processes. Our preferred slip model provides support for the proposed kinematic model that attributes the extension in central Sulawesi to gravitational collapse, in which mass lateral extrusion along the large‐scale Palu‐Koro strike‐slip fault played an important role.〈/span〉

Description: Phosphorous and nitrogen are electrically active species at the SiO 2 /SiC interface in SiC MOSFETs. We compare the concentration, chemical bonding, and etching behavior of P and N at the SiO 2 /SiC(0001) interface using photoemission, ion scattering, and secondary ion mass spectrometry. Both interfacial P and N are found to be resistant to buffered HF solution etching at the SiO 2 /SiC(0001) interface while both are completely removed from the SiO 2 /Si interface. The medium energy ion scattering results of etched phosphosilicate glass/SiC not only provide an accurate coverage but also indicate that both the passivating nitrogen and phosphorus are confined to within 0.5 nm of the interface. Angle resolved photoemission shows that P and N are likely situated in different chemical environments at the interface. We conclude that N is primarily bound to Si atoms at the interface while P is primarily bound to O and possibly to Si or C. Different interface passivating element coverages and bonding configurations on different SiC crystal faces are also discussed. The study provides insights into the mechanisms by which P and N passivate the SiO 2 /SiC(0001) interface and hence improve the performance of SiC MOSFETs.

Description: This paper reports initial the demonstration of prototype Ge 1− x − y Si x Sn y light emitting diodes with distinct direct and indirect edges and high quality I-V characteristics. The devices are fabricated on Si (100) wafers in heterostructure pin geometry [ n -Ge/ i -Ge 1− x − y Si x Sn y / p -Ge(Sn/Si)] using ultra low-temperature (T 

Description: 〈span〉〈div〉ABSTRACT〈/div〉Determining how faults behave during large earthquakes can help provide insight into the mechanism of regional tectonism. Here, we use Advanced Land Observing Satellite‐2 (ALOS‐2) and Sentinel‐1 Interferometric Synthetic Aperture Radar (InSAR) data to estimate the source parameters of the 2017 Mw 6.6 Poso earthquake, eastern Indonesia. The results show that the coseismic rupture was predominated by normal faulting at depths of 3–10 km, whereas some distinct dextral strike slip is also resolved along the down‐dip direction of normal‐faulting zones. We analyze the background seismicity, regional topography, and fault kinematics to investigate the present‐day tectonics of central Sulawesi as well as its evolutionary processes. Our preferred slip model provides support for the proposed kinematic model that attributes the extension in central Sulawesi to gravitational collapse, in which mass lateral extrusion along the large‐scale Palu‐Koro strike‐slip fault played an important role.〈/span〉

Description: Supercritical carbon dioxide (scCO 2 ) processing has been proven as a method for preparing polymer/montmorillonite (MMT) nanocomposites with improved platelet dispersion. The influence of scCO 2 processing on the shape and size of the MMT tactoid/platelet, which is of great importance to the final platelet dispersion in the polymer matrix, is scarcely reported in the literature. In the present study, the pristine MMT was first surface modified with 3-glycidoxypropyltrimethoxysilane (the grafted MMT is labeled as GMMT), and then intercalated using three kinds of intercalating agents, myristyltrimethylammonium bromide (MTAB), tetradecyltrihexylphosphonium chloride (TDTHP), and ethoxyltriphenylphosphonium chloride (ETPC), in water or scCO 2 , to study the effect of intercalating agent type and intercalation method on the morphology and thermal properties of GMMT, as a part of a program devoted to the synthesis of polymer/MMT nanocomposites. The structure of intercalated GMMT was characterized by thermogravimetric analysis, X-ray powder diffraction, and scanning electron microscopy (SEM). The optimum intercalation conditions in scCO 2 were established by trying a range of reaction times and pressures. The structures of intercalated GMMT obtained under optimum scCO 2 conditions and water were compared. The basal spacing of GMMT intercalated in scCO 2 was almost the same as that in water, and both were obviously larger than that of GMMT. The GMMT exhibited a compact spherical morphology (examined using SEM), and the surface structures (including surface morphology, surface roughness, and surface compactness) of samples intercalated in water became ‘less compact’ and the degree of the ‘compactness’ of samples intercalated in scCO 2 decreased further. Whether in water or scCO 2 , samples intercalated with TDTHP exhibited a larger basal spacing and the extent of disorder increased compared to that for samples intercalated with MTAB. The pristine MMT was also intercalated for comparison and silane grafting was proven to contribute to the increased basal spacing and ‘less compact’ surface structure.

Description: The distribution of landslides induced by the 2008 M w  7.9 Wenchuan earthquake was investigated following the method of Meunier et al. (2007) to examine the relationships to peak ground acceleration (PGA). Results suggest that landslide densities are quantifiably related to PGA. Thresholds of PGA cr for landslide failure are for average horizontal PGA and for average vertical PGA. As with other earthquakes, the distribution of the Wenchuan earthquake-triggered landslides can be described by two equations, based on area and source densities, respectively. The similar damping factors of ~20 in these two equations suggest that both density distribution patterns of landslides reflect the dissipation of seismic energy. Landslide-derived PGA equations were then produced for the hanging-wall region of the earthquake-affected area. The results indicate that it should be possible to produce an earthquake shake map from the distribution of earthquake-triggered landslides in an area where there are few or no seismic instruments but many landslides.

Description: We present the results of kilohertz mechanical spectrum of perovskite (La 1−x Pr x ) 1/3 Sr 2/3 FeO 3−δ (x = 0 to 1) samples. An oxygen vacancy related internal friction peak was observed around 400 K in oxygen nonstoichiometric La 1/3 Sr 2/3 FeO 3−δ and Pr 1/3 Sr 2/3 FeO 3−δ samples. An octahedral tilting P m 3 ¯ m ↔ R 3 ¯ c transition appeared as a step-like decrease of modulus with the decrease in temperature in less oxygen nonstoichiometric (La 1−x Pr x ) 1/3 Sr 2/3 FeO 3−δ samples. Another unsymmetrical internal friction peak due to the relaxation of domain walls was observed just below the tilting transition. The different behavior of oxygen vacancies and their complicate interaction with ferroelastic domains were suggested in various oxygen nonstoichiometric La 1/3 Sr 2/3 FeO 3−δ and Pr 1/3 Sr 2/3 FeO 3−δ samples.

Description: 〈sec〉〈st〉Synopsis〈/st〉〈p〉〈textbox textbox-type="graphic"〉〈p〉〈inline-fig〉〈/inline-fig〉〈/p〉〈/textbox〉〈/p〉 〈p〉Combining genetic lineage tracing and single-cell gene expression analyses, this resource deciphers the multistep trajectories of endocrine and exocrine lineages and intermediate progenitor populations during early murine pancreas development.〈/p〉 〈p〉 〈l type="unord"〉〈li〉〈p〉Single-cell analysis of cell lineages from fetal pancreas at E9.5–E17.5 identifies differentiation steps and pathways from multipotent progenitors to endocrine and exocrine lineages.〈/p〉〈/li〉 〈li〉〈p〉Fifteen cell clusters delineate all pancreatic cell types and four steps of cell fate decisions from progenitors to islet lineages.〈/p〉〈/li〉 〈li〉〈p〉Developmental pathways involved in the "first wave" of alpha-cell generation differ from intermediate progenitor and population specific markers.〈/p〉〈/li〉 〈li〉〈p〉Endocrine progenitors undergo four transient stages.〈/p〉〈/li〉 〈li〉〈p〉The MAPK/ERK pathway restrains early endocrine specification.〈/p〉〈/li〉〈/l〉 〈/p〉〈/sec〉

Description: Article Electron doping is a powerful way to induce quantum phase transitions in materials and explore exotic states of matter. Here, Wen et al. present carefully-controlled potassium dosing in FeSe films and FeSe 0.93 S 0.07 bulk, which enhances superconductivity and induces other anomalous phases, revealing a complex phase diagram. Nature Communications doi: 10.1038/ncomms10840 Authors: C. H. P. Wen, H. C. Xu, C. Chen, Z. C. Huang, X. Lou, Y. J. Pu, Q. Song, B. P. Xie, Mahmoud Abdel-Hafiez, D. A. Chareev, A. N. Vasiliev, R. Peng, D. L. Feng

Description: This paper describes a controlled-source audio-frequency magnetotellurics (CSAMT) survey conducted in August 2009 over a potential high-level radioactive waste (HLRW) disposal site in northwestern China. The site is primarily covered with well-developed metamorphic rocks. The purpose of the CSAMT survey was to map the outcropped faults to depth and identify any hidden faults or weakened zone in the subsurface. The site is located in the arid Beishan area, Gansu Province. Substantial challenges were encountered in acquiring quality electrical field data because of the highly resistive ground. Satisfactory electrode contact conditions were generally maintained by applying salt-saturated water to both the transmitting electrodes and the receiving electrodes. The excitation frequency ranges from 9,600 Hz to 1 Hz with a target depth of investigation of 1,000 m. The CSAMT data were processed in several steps. Low-pass filtering was applied to remove the static effect caused by the local electrical inhomogeneities near the ground surface. An optimum filter length was found through experiment to yield the maximum static effect reduction. The pre-processed data are inverted for geoelectrical cross sections using a 2-D inversion method. Inversion artifacts were suppressed by imposing a model smoothness constraint. The inversion reveals several important results. First, the inversion cross sections correctly recognized the fractures and deformation bands mapped at the surface. The cross sections also identified four new faults that were not observed in the geological survey. The inversion profiles suggested that the narrow factures and deformation bands observed along survey line 1 extend to a great depth. The profile helped identify a possible weak mineralization zone along survey line 2. Considering the regional tectonic stress direction, the lower resistivity zone suggests that the faults parallel to survey line 2 are subject to an extensional or transtensional force that produces a broad and broken alteration zone. Although subject to further drilling confirmation, these interpretation results greatly enhance the understanding of the deep geological hazards at the Beishan site.