We report a novel Mn-Co-Ni-O (MCN) nanocomposite in which the p-type semiconductivity of Mn-Co-Ni-O can be manipulated by addition of graphene. With an increase of graphene content, the ...semiconductivity of the nanocomposite can be tuned from p-type through electrically neutral to n-type. The very low effective mass of electrons in graphene facilitates electron tunneling into the MCN, neutralizing holes in the MCN nanoparticles. XPS analysis shows that the multivalent manganese ions in the MCN nanoparticles are chemically reduced by the graphene electrons to lower-valent states. Unlike traditional semiconductor devices, electrons are excited from the filled graphite band into the empty band at the Dirac points from where they move freely in the graphene and tunnel into the MCN. The new composite film demonstrates inherent flexibility, high mobility, short carrier lifetime, and high carrier concentration. This work is useful not only in manufacturing flexible transistors, FETs, and thermosensitive and thermoelectric devices with unique properties but also in providing a new method for future development of 2D-based semiconductors.
It is the first time to demonstrate the comparison of isotropic/anisotropic wettability between dual-scale micro-nano-rods and single-scale micro-rods. Inspired by the natural structures of rice ...leaf, a series of micro-nano-rods and micro-rods with different geometric parameters were fabricated using micro-fabrication technology. Experimental measured apparent contact angles and advancing and receding contact angles from orthogonal orientations were characterized. The difference of contact angles from orthogonal orientation on dual-scale rods was much smaller than those on single-scale rods in both static and dynamic situation. It indicated that the dual-scale micro-nano-rods showed isotropic wettability, while single-scale micro-rods showed anisotropic wettability. The switch of isotropic/anisotropic wettability could be illustrated by different wetting state and contact line moving. It offers a facial way to switch isotropic/anisotropic wettability of the surface via dual-scale or single-scale structure.
Novel C-F-S-H/PCE (calcium-ferrite-silicate-hydrates/polycarboxylate ether) nanocomposites were synthesized successfully by incorporating Fe3+ during the synthesis of C-S-H/PCE. The results of ...isothermal heat flow calorimetry and compressive strength tests indicated that C-F-S-H/PCE nanocomposites showed high-efficiency seeding effect on early cement hydration due to the higher absorption of PCE and smaller particle size of nano-seeds than those of traditional C-S-H/PCE nanocomposites. And the best seeding effect of C-F-S-H/PCE nanocomposites was identified when the Ca/Si and Fe/Si were 1.0 and 0.03 respectively. Moreover, the incorporation of Fe3+ did not affect the concentration of free calcium in the C-F-S-H/PCE suspension whose morphologies were composed of irregular globules and network gel. Additionally, the incorporated Fe3+ made the semi-crystalline C-S-H structure more amorphous though it was not a direct factor that affected the seeding effect of the nanocomposites. All in all, this study provided a new idea from modified seeding nanocomposites for low-CO2 cement and a basis for the production of nano-seeds based on Fe-rich wastes.
Eicosanoids, oxidized fatty acids that serve as cell-signaling molecules, have been broadly implicated in tumorigenesis. Here, we aimed to identify eicosanoids associated with pancreatic ...tumorigenesis and the cell types responsible for their synthesis.
We profiled normal pancreas and pancreatic ductal adenocarcinoma in mouse models and patient samples using mass spectrometry. We interrogated RNA sequencing data sets for eicosanoid synthase or receptor expression. Findings were confirmed by immunostaining.
In murine models, we identified elevated levels of prostaglandin D2 (PGD2), prostacyclin, and thromboxanes in neoplasia while prostaglandin E2 (PGE2), 12-HHTre, HETEs, and HDoHEs are elevated specifically in tumors. Analysis of single-cell RNA sequencing data sets suggests that PGE2 and prostacyclins are derived from fibroblasts, PGD2, and thromboxanes from myeloid cells, and PGD2 and 5-HETE from tuft cells. In patient samples, we identified a transition from PGD2- to PGE2-producing enzymes in the epithelium during the transition to pancreatic ductal adenocarcinoma, fibroblast/tumor expression of PTGIS, and myeloid/tumor cell expression of TBXAS1.
Our analyses identify key changes in eicosanoid species during pancreatic tumorigenesis and the cell types that contribute to their synthesis. Thromboxane and prostacyclin expression is conserved between animal models and human disease and may represent new druggable targets.
Selective laser melting (SLM) is a promising additive manufacturing technique with growing acceptance in aerospace applications. In this work, a new aeronautical material of near-α Ti alloy (TA15) ...for SLM was firstly investigated and analyzed before and after annealing, mainly including mechanical properties, microstructural evolution. The distinctions between SLMed TA15 and wrought TA15 are also discussed in this study. Firstly, near full density TA15 samples (99.98%) were fabricated by SLM utilizing the optimized processing parameters. Then microstructures and textures are characterized and analyzed by optical microscope, X-ray diffractometer, scanning electron microscope and transmission electron microscope. Furthermore, mechanical properties of TA15 samples are measured via tensile and hardness test, considering the impacts of building direction. The results show that both the as-built and the annealed SLMed samples exhibit significantly weak textures and unconspicuous anisotropy of mechanical properties. It has been identified that αʹ martensite is dominant in the as-built microstructure thus contributing to ~1296 MPa in ultimate strength and ~398 HV in hardness which are 35% and 24% higher than those of wrought material. However, a low plasticity with ~7.6% of elongation at break was observed. After annealing, SLMed samples exhibited excellent comprehensive mechanical properties with 51% improvement at elongation through elimination of residual stress and precipitation of nanometer size β phase in the fine basket-weave structure.
We describe a simple but efficient technique to fabricate large-scale arrays of highly ordered silicon nanostructures. By coupling dual lithography using light of 351.1 nm wavelength with deep ...reactive ion etching(DRIE), silicon nanostructures of excellent regularity and uniform coverage were achieved. The proposed nanofabrication method not only simplified the nanofabrication process but also produced highaspect-ratio(higher than 15) nanostructures. The scalloping problem was also controlled by regulating DRIE parameters. The process is rapid, cheap, examined to optimize the fabrication process, and has the potential to be scaled up to large areas. The contact angle of a water droplet atop the surface is larger than 150?.Moreover, by coupling black silicon process with DRIE-based microfabrication, three-dimensional nano/nano dual-scale structures which show robust and stable hydrophobicity have been achieved. This process opens new application possibilities in optical, photoelectric, microelectronic, catalytic and biomedical applications.
In this paper, we proposed a dynamic demodulation technique for tandem dual-cavity (Extrinsic Fabry-Perot Interferometer) EFPI sensors, which enabled the simultaneous real-time temperature ...measurement in harsh environment. The concept of tandem dual-cavity EFPI was presented and used to design a pressure/temperature sensor as well as the dynamic demodulation method. A window function FIR digital filter was designed to separate the pressure sensitive EFPI (PS-EFPI) and thermal sensitive (TS-EFPI). The Cross-correlation method was used to demodulate the OPD of cavities from the filtered PS-EFPI and TS-EFPI spectrum signals. An FPGA based hardware system with maximum data processing speed up to 25kHz was developed to provide high-speed computational resources for the filtering and demodulation processes. Characterization experiments indicated that the sensor and the proposed demodulation system were able to simultaneously detect static pressure up to 4MPa and temperature up to 1200°C. The pressure sensitivity varies from 0.92nm/kPa (20 °C) to 1.18nm/kPa (1200 °C), while the temperature sensitivity is 3.73nm/°C. Dynamic pressure sensing experiments indicated excellent dynamic properties of demodulation system as well as sensor, the maximum sensitivity for sinusoidal dynamic pressure is 0.241nm/kPa (@10Hz), while the minimum response time for step dynamic pressure is 37.4μs (@70kPa). In this work, innovative progress has been made in realizing dynamic demodulation of dual-cavity EFPI-type sensor for harsh environment, which holds great potential for practical harsh environment applications, such as aero turbine engines, etc.
The further advance of membrane distillation (MD) is hampered due to inadequate membrane durability challenged by wetting-induced performance deterioration. The current study presents a novel ...approach to fabrication of superhydrophobic polyvinylidene fluoride (PVDF) membranes via construction of hierarchical textures on membrane surfaces based on a nanocasting strategy. Two types of PVDF membranes with different surface textures were prepared, separately using a stainless-steel mesh (SSM) or its negative polydimethylsiloxane (PDMS) template as a fabrication substrate. The obtained membranes were systematically characterized in terms of membrane morphology, wetting behavior, MD performance, and antifouling performance. Consequently, the PDMS-based membrane obtained a plaited surface texture, resulting in a high static contact angle of ~153° and a high sliding angle of >90°. The resultant parahydrophobic membrane surface resembled a petal surface. The SSM-based membrane obtained a wave-like pattern, resulting in a high static contact angle of ~164° and a low sliding angle of ~6.8°. The resultant superhydrophobic membrane surface resembled a lotus leave surface. Moreover, both membranes achieved higher water flux and enhanced antifouling performance with no significant compromise in salt rejection. Particularly, the SSM-based membrane achieved the highest flux and best antifouling performance, suggesting promising applications in various fields.
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•Superhydrophobic membrane was fabricated via nanocasting with stainless-steel mesh.•The SSM-based membrane has a wave-like texture resembling a lotus leave surface.•The PDMS-based membrane has a plaited texture resembling a petal surface.•Textured membranes achieved dramatically improved MD and antifouling performance.
ABSTRACT We characterize the radial density, metallicity, and flattening profile of the Milky Way's stellar halo, based on the large sample of spectroscopically confirmed giant stars from ...SDSS/SEGUE-2, spanning galactocentric radii 10 kpc ≤ rGC ≤ 80 kpc. After excising stars that were algorithmically attributed to apparent halo substructure (including the Sagittarius stream), the sample has 1757 K giants, with a typical metallicity precision of 0.2 dex and a mean distance accuracy of 16%. Compared to blue horizontal branch stars or RR Lyrae variables, giants are more readily understood tracers of the overall halo star population, with less bias in age or metallicity. The well-characterized selection function of the sample enables forward modeling of those data, based on ellipsoidal stellar density models, *(R, z), with Einasto profiles and (broken) power laws for their radial dependence, combined with a model for the metallicity gradient and the flattening profile. Among models with constant flattening, these data are reasonably well fit by an Einasto profile of n = 3.1 0.5 with an effective radius and a flattening of q = 0.7 0.02, or comparably well by an equally flattened broken power law, with radial slopes of in = 2.1 0.3 and out = 3.8 0.1, with a break radius of rbreak = 18 1 kpc; this is largely consistent with earlier work. We find a modest but significant metallicity gradient within the "outer" stellar halo, Fe/H decreasing outward. If we allow for a variable flattening , we find the distribution of halo giants to be considerably more flattened at small radii, q(10 kpc) = 0.55 0.02, compared to q(>30 kpc) = 0.8 0.03. Remarkably, the data are then very well fit by a single power law with index of 4.2 0.1 on the variable . In this simple and better-fitting model, there is a break in flattening at ∼20 kpc, instead of a break in the radial density function. While different parameterizations of the radial profile vary in their parameters, their implied density gradient, , is stable along a direction intermediate between major and minor axis; this gradient is crucial in any dynamical modeling that uses halo stars as tracers.
•The response surface experimental method is used to accurately obtain the ratio of similar materials.•The failure mechanism of the automatically formed roadway in thick-hard roof is explored.•A ...cooperative control technique of increasing the gangue volume in the goaf and improving the strength of coal rib is proposed.
Automatically formed roadways (AFR) are highly susceptible to extreme deformation and damage under thick-hard roof geological conditions. Taking the thick-hard roof of the Yushuquan coal mine as a case study, this paper mainly studies the extreme deformation, failure mechanism, and control technology of the AFR. First of all, through on-site monitoring, the maximum vertical convergence rate of the AFR in thick-hard roof reaches 44.8 mm/d. The failure of the AFR mainly focuses on the roof sinking, coal rib rupture, and deformation of gangue prevention structure. Then, a model test was employed to analyze the deformation characteristics of the AFR, including the roadway roof, roadway floor, solid coal rib, and gangue rib. Furthermore, the failure mechanism of the AFR in thick-hard roof is explored. The model test shows that the rotation and subsidence of the roadway roof strata are the main factors causing the AFR damage. In turn, the subsidence of the roadway roof strata is controlled by the movement and distribution characteristics of the hard rock blocks within the cutting range. Eventually, cooperative control technology was proposed, including increasing the gangue volume in the goaf and increasing the coal rib strength to control the extreme deformation of the AFR in thick-hard roof conditions. Field engineering application demonstrates that the deformation of AFR surrounding rock is effectively controlled under thick-hard roof. The research findings can serve as a valuable reference for the prevention and control of the stability of AFR under complex geological conditions.
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