389 research outputs found
A novel bath lily-like graphene sheet-wrapped nano-Si composite as a high performance anode material for Li-ion batteries
A novel bath lily-like graphene sheet-wrapped nano-Si composite synthesized via a simple spray drying process exhibits a high reversible capacity of 1525 mAh g(-1) and superior cycling stability, which could be attributed to a synergistic effect between highly conductive graphene sheets and active nanoparticles in the open nano/micro-structure
Study of Mid-Infrared Optical Properties of ZnS Thin Films by Spectroscopic Ellipsometry
In order to obtain the mid-infrared optical properties of ZnS thin films, ZnS films with different thickness were prepared on K9 glass substrate by electronic beam evaporation. They were denoted by Aã€Bã€C . The optical properties of thin films were studied by Spectroscopic Ellipsometry. The measured date of film A ã€Bã€C were fitted by Brendel oscillator, and based on ZnS film properties and the film forming characteristic of the ZnS film, building the model“substrate(K9 glass)/EMA(50% K9 glass and 50% ZnS)/ZnS/rough surface layer(50% ZnS and 50% air)/airâ€. The optical constants curve and thickness of ZnS thin film were got. The results shown that the evaluation function MSE is small when Brendel model is used in data fitting. Within the wavelength range of 3000nm ~ 12500nm, the ZnS thin films refractive index and extinction coefficient are reduced with increasing wavelength. The Extinction coefficient tends to zero near the long wavelengh. The thickness of ZnS measured value was closest to the theoretical value. The results have certain reference value to measurement and preparation of high quality ZnS thin film
In situ growth of SnO2 on graphene nanosheets as advanced anode materials for rechargeable lithium batteries
Graphene with a single layer of carbon atoms densely packed in a honeycomb crystal lattice is one of attractive materials for the intercalation of lithium ion, but it has low volumetric capacity owing to low tap density. We report a method for in situ growth of SnO2 on graphene nanosheets (SGN) as anode materials for rechargeable lithium batteries. The results indicated that the SnO2 nanoparticles with size in the range of 5-10 nm and a polycrystalline structure are homogeneously supported on graphene nanosheets. The charge and discharge capacities of SGN attained to 1559.7 and 779.7 mAh/g in the first cycle at a current density of 300 mA/g. The specific discharge capacities remained at 620 mAhâ‹…g-1 in the 200th cycle. The SGN exhibits a superior Listorage performance with good cycle life and high capacity
Visualizing the elongated vortices in -Ga nanostrips
We study the magnetic response of superconducting -Ga via low
temperature scanning tunneling microscopy and spectroscopy. The magnetic vortex
cores rely substantially on the Ga geometry, and exhibit an unexpectedly-large
axial elongation with aspect ratio up to 40 in rectangular Ga nano-strips
(width 100 nm). This is in stark contrast with the isotropic circular
vortex core in a larger round-shaped Ga island. We suggest that the unusual
elongated vortices in Ga nanostrips originate from geometric confinement effect
probably via the strong repulsive interaction between the vortices and Meissner
screening currents at the sample edge. Our finding provides novel conceptual
insights into the geometrical confinement effect on magnetic vortices and forms
the basis for the technological applications of superconductors.Comment: published in Phys. Rev. B as a Rapid Communicatio
Critical Role of FoxO1 in Granulosa Cell Apoptosis Caused by Oxidative Stress and Protective Effects of Grape Seed Procyanidin B2
Reactive oxygen species (ROS) are closely related to the follicular granulosa cell apoptosis. Grape seed procyanidin B2 (GSPB2) has been reported to possess potent antioxidant activity. However, the GSPB2-mediated protective effects and the underlying molecular mechanisms in granulosa cell apoptosis process remain unknown. In this study, we showed for the first time that GSPB2 treatment decreased FoxO1 protein level, improved granulosa cell viability, upregulated LC3-II protein level, and reduced granulosa cell apoptosis rate. Under a condition of oxidative stress, GSPB2 reversed FoxO1 nuclear localization and increased its level in cytoplasm. In addition, FoxO1 knockdown inhibited the protective effects of GSPB2 induced. Our findings suggest that FoxO1 plays a pivotal role in regulating autophagy in granulosa cells, GSPB2 exerts a potent and beneficial role in reducing granulosa cell apoptosis and inducing autophagy process, and targeting FoxO1 could be significant in fighting against oxidative stress-reduced female reproductive system diseases
Applying hybrid clustering in pulsar candidate sifting with multi-modality for FAST survey
Pulsar search is always the basis of pulsar navigation, gravitational wave
detection and other research topics. Currently, the volume of pulsar candidates
collected by Five-hundred-meter Aperture Spherical radio Telescope (FAST) shows
an explosive growth rate that has brought challenges for its pulsar candidate
filtering System. Particularly, the multi-view heterogeneous data and class
imbalance between true pulsars and non-pulsar candidates have negative effects
on traditional single-modal supervised classification methods. In this study, a
multi-modal and semi-supervised learning based pulsar candidate sifting
algorithm is presented, which adopts a hybrid ensemble clustering scheme of
density-based and partition-based methods combined with a feature-level fusion
strategy for input data and a data partition strategy for parallelization.
Experiments on both HTRU (The High Time Resolution Universe Survey) 2 and FAST
actual observation data demonstrate that the proposed algorithm could
excellently identify the pulsars: On HTRU2, the precision and recall rates of
its parallel mode reach 0.981 and 0.988. On FAST data, those of its parallel
mode reach 0.891 and 0.961, meanwhile, the running time also significantly
decrease with the increment of parallel nodes within limits. So, we can get the
conclusion that our algorithm could be a feasible idea for large scale pulsar
candidate sifting of FAST drift scan observation
Prevalence, awareness, treatment and control of dyslipidemia among adults in Northwestern China: the cardiovascular risk survey
The Large Sky Area Multi-object Fiber Spectroscopic Telescope (LAMOST) Quasar Survey: Quasar Properties from Data Release Six to Nine
We report the fourth installment in the series of the Large Sky Area
Multi-Object Fiber Spectroscopic Telescope (LAMOST) Quasar Survey, which
includes quasars observed between September, 2017 and June, 2021. There are in
total 13,066 quasars reliably identified, of which 6,685 are newly discovered
that are not reported in the SDSS DR14 quasar catalog or Million Quasars
catalog. Because LAMOST does not provide accurate absolute flux calibration, we
re-calibrate the spectra with the SDSS/Pan-STARRS1 multi-band photometric data.
The emission line properties of H, H, Mg\,{\sc ii} and C\,{\sc
iv}, and the continuum luminosities are measured by fitting the re-calibrated
spectra. We also estimate the single-epoch virial black hole masses () using the derived emission line and continuum parameters. This is the
first time that the emission line and continuum fluxes were estimated based on
LAMOST re-calibrated quasar spectra. The catalog and spectra for these quasars
are available online. After the nine-year LAMOST quasar survey, there are in
total 56,175 identified quasars, of which 24,127 are newly discovered. The
LAMOST quasar survey not only discovers a great number of new quasars, but also
provides a database for investigating the spectral variability of the quasars
observed by both LAMOST and SDSS, and finding rare quasars including
changing-look quasars and broad absorption line quasars.Comment: arXiv admin note: text overlap with arXiv:1811.01570, Accepted by
ApJ
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