An ordered mesoporous WO3 material with a highly crystalline framework was synthesized by using amphiphilic poly(ethylene oxide)-b-polystyrene (PEO-b-PS) diblock copolymers as a structure-directing agent through a solvent-evaporation-induced self-assembly method combined with a simple template-carbonization strategy. The obtained mesoporous WO3 materials have a large uniform mesopore size (ca. 10.9 nm) and a high surface area (ca. 121 m(2) g(-1)). The mesoporous WO3-based H2S gas sensor shows an excellent performance for H2S sensing at low concentration (0.25 ppm) with fast response (2 s) and recovery (38 s). The high mesoporosity and continuous crystalline framework are responsible for the excellent performance in H2S sensing.
We report the results of our systematic survey for Galactic 6.7 GHz Class II CH 3 OH maser emission toward a sample of young stellar objects. The survey was conducted with the Shanghai Tianma Radio Telescope (TMRT). The sample consists of 3348 sources selected from the all-sky Wide-Field Infrared Survey Explorer (WISE) point source catalog. We have discussed the selection criteria in detail and the detection results of those at high Galactic latitudes (i.e. |b| > 2 • ) in a previous paper (paper I). Here, we present the results from the survey of those at low Galactic latitudes, i.e. |b| < 2 • . Of 1875 selected WISE point sources, 291 positions that were actually associated with 224 sources were detected with CH 3 OH maser emission. Among them, 32 are newly detected. Majority of the newly detected sources are associated with bright WISE sources. The majority of the detected sources (209/224 = 93.3%) are quite close to the Galactic Plane (|b| < 1 • ) and lie on the inner spiral arms with positive LSR velocities. Detection rate and the color-color distribution of our detection are all matched with our anticipation. Combining with detections from previous surveys, we compile a catalogue of 1085 sources with 6.7 GHz CH 3 OH maser emission in our Galaxy.
Abstract:This study uses apatite fission track (FT) analysis to constrain the exhumation history of bedrock samples collected from the Altai Mountains in northern Xinjiang, China. Samples were collected as transects across the main structures related to Palaeozoic crustal accretion events. FT results and modeling identify three stages in sample cooling history spanning the Mesozoic and Tertiary. Stage one records rapid cooling to the low temperature part of the fission track partial annealing zone circa 70±10°C. Stage two, records a period of relative stability with little if any cooling taking place between ~ 75 Ma and ~25-20 Ma suggesting the Altai region had been reduced to an area of low relief. Support for this can be found in the adjacent Junngar Basin that received little if any sediment during this interval. Final stage cooling took place in the Miocene at an accelerated rate bringing the sampled rocks to the Earth's surface. This last stage, linked to the far field effects of the Himalayan collision, most likely generated the surface uplift and relief that define the present-day Altai Mountains.
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