18,849 research outputs found
Healing Carbon Fiber/Polymer Composites by Resistive Heating
Interface is the key region which determines, to a great extent, the set of properties of all
heterogeneous systems, including composite materials. We reported interface healing of carbon fiber
reinforced thermoplastic composite material via resistive heating. The carbon fiber, T700 carbon fiber,
with a resistivity of 1.66·10-3 Ω·cm was used as the heating element while the matrix is polyarylether
sulfone with cardo. Micro-droplet experiment was used to study the interface strength before and after
heating to determine the healing efficiency. The measurement shows (experimental results show) that
resistive heating is an efficient way to heal cracks near interface.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3527
Porous Graphitic Carbon Nitride Nanosheets by Pre-polymerization for Enhanced Hydrogen Evolution from Water Splitting under Solar Light
A facile and green method was developed to fabricate porous graphitic carbon nitride (g-C3N4) nanosheets by simple pre-polymerizing melamine. Porous structures were formed in polymerized g-C3N4 at 350∘C for 2h, which greatly enhanced the specifi surface area and pore volume, resulting in superior photocatalytic evolution. The hydrogen evolution rate was 11.2 higher than that of bulk g-C3N4 under visible light. The porous structure not only provided abundant active catalytic sites and cross-plane diffusion channels to facilitate the charge and mass transportation, but also promoted the charge separation in the photocatalytic reaction. This g-C3N4 is suitable for mass-production to generate hydrogen from water splitting.
Keywords: graphitic carbon nitride, photocatalytic, porous structures, prepolymerization, hydrogen evolution from water splittin
Label Transfer from APOGEE to LAMOST: Precise Stellar Parameters for 450,000 LAMOST Giants
In this era of large-scale stellar spectroscopic surveys, measurements of
stellar attributes ("labels," i.e. parameters and abundances) must be made
precise and consistent across surveys. Here, we demonstrate that this can be
achieved by a data-driven approach to spectral modeling. With The Cannon, we
transfer information from the APOGEE survey to determine precise Teff, log g,
[Fe/H], and [/M] from the spectra of 450,000 LAMOST giants. The Cannon
fits a predictive model for LAMOST spectra using 9952 stars observed in common
between the two surveys, taking five labels from APOGEE DR12 as ground truth:
Teff, log g, [Fe/H], [\alpha/M], and K-band extinction . The model is then
used to infer Teff, log g, [Fe/H], and [/M] for 454,180 giants, 20% of
the LAMOST DR2 stellar sample. These are the first [/M] values for the
full set of LAMOST giants, and the largest catalog of [/M] for giant
stars to date. Furthermore, these labels are by construction on the APOGEE
label scale; for spectra with S/N > 50, cross-validation of the model yields
typical uncertainties of 70K in Teff, 0.1 in log g, 0.1 in [Fe/H], and 0.04 in
[/M], values comparable to the broadly stated, conservative APOGEE DR12
uncertainties. Thus, by using "label transfer" to tie low-resolution (LAMOST R
1800) spectra to the label scale of a much higher-resolution (APOGEE R
22,500) survey, we substantially reduce the inconsistencies between
labels measured by the individual survey pipelines. This demonstrates that
label transfer with The Cannon can successfully bring different surveys onto
the same physical scale.Comment: 27 pages, 14 figures. Accepted by ApJ on 16 Dec 2016, implementing
suggestions from the referee reports. Associated code available at
https://github.com/annayqho/TheCanno
Nonsaturating magnetoresistance and nontrivial band topology of type-II Weyl semimetal NbIrTe4
Weyl semimetals, characterized by nodal points in the bulk and Fermi arc
states on the surface, have recently attracted extensive attention due to the
potential application on low energy consumption electronic materials. In this
report, the thermodynamic and transport properties of a theoretically predicted
Weyl semimetal NbIrTe4 is measured in high magnetic fields up to 35 T and low
temperatures down to 0.4 K. Remarkably, NbIrTe4 exhibits a nonsaturating
transverse magnetoresistance which follows a power-law dependence in B.
Low-field Hall measurements reveal that hole-like carriers dominate the
transport for T 80 K, while the significant enhancement of electron
mobilities with lowering T results in a non-negligible contribution from
electron-like carriers which is responsible for the observed non-linear Hall
resistivity at low T. The Shubnikov-de Haas oscillations of the Hall
resistivity under high B give the light effective masses of charge carriers and
the nontrivial Berry phase associated with Weyl fermions. Further
first-principles calculations confirm the existence of 16 Weyl points located
at kz = 0, 0.02 and 0.2 planes in the Brillouin zone.Comment: 5 figures, 1 tabl
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