26 research outputs found
Study of damage characteristics in composite structures from simulated lightning strikes
This work investigated experimentally the direct effects of simulated lightning strikes in carbon/epoxy and E-glass/epoxy laminates. The direct effects were represented by Joule heating and kinetic shock waves. The experimental set-up was designed to maximize these direct effects by employing a solid electrode, pointed vertically to the surface of the specimens with a small electrode gap. The damage mechanisms were found to be in the form of resin sublimation, delamination and fibre tufting. The damage characteristics depended on type of composite materials, lightning current and action integral. In the carbon/epoxy laminates, resin sublimation and degradation were dominant at relatively low currents and with the further increase in current fibre tufting appeared due to kinetic shock waves. Penetration into the laminates was found to be limited to the only top two plies in the extreme case. The damage characteristics of the E-glass/epoxy laminates with a tiny hole were dominated by extensive delamination due entirely to shock waves with little sign of Joule heating. Analytical work will be desired to aid establishment of relationships between the damage characteristics and the lightning strike parameters via lightning channel radius and raised temperatures
Multilayer CuO@NiO Hollow Spheres: Microwave-Assisted Metal–Organic-Framework Derivation and Highly Reversible Structure-Matched Stepwise Lithium Storage
A unique CuO@NiO microsphere with three-layer ball-in-ball hollow morphology is successfully synthesized by Cu–Ni bimetallic organic frameworks. The beforehand facile microwave-assisted production of the Ni organic framework sphere is used as the template to induce the morphology control of bimetallic oxides. Designed by the controlled surface cationic exchange reactions between Cu and Ni ions, there is an elemental gradient (decreased amount of CuO but increased amount of NiO) from the shell to the core of the microsphere product. This ternary metal oxide hollow structure is found to be very suitable for solving the critical volume expansion problem, which is critical for all high-capacity metal oxide electrodes for lithium ion batteries. A reversible larger-than-theoretical capacity of 1061 mAh·g<sup>–1</sup> can be retained after a repetitive 200 cycles without capacity fading compared to the initial cycle. These excellent electrochemical properties are ascribed to the step-by-step lithium insertion reactions induced by the matched CuO@NiO composition from the shell to the core and facilitated lithium/electron diffusion and accommodated volume change in the porous bimetallic oxides microsphere with a multiple-layer yolk–shell nanostructure
Microwave Hydrothermal Synthesis of Ni-based Metal–Organic Frameworks and Their Derived Yolk–Shell NiO for Li-Ion Storage and Supported Ammonia Borane for Hydrogen Desorption
This paper reports fast microwave
hydrothermal synthesis of Ni-based
metal–organic frameworks (Ni-MOFs) and their derived yolk–shell
NiO structures by direct calcination in air. The molar ratio of the
Ni ion to the benzene-1,3,5-tricarboxylic acid (H<sub>3</sub>BTC)
ligand has important influence on the NiO morphologies and their electrochemical
performances. The obtained yolk–shell NiO microsphere displays
a large reversible capacity of 1060 mAh g<sup>–1</sup> at a
small current density of 0.2 A g<sup>–1</sup> and a good high-rate
capability when evaluated as an anode for rechargeable lithium-ion
batteries. Moreover, the facilitated hydrogen release from ammonia
borane (AB) at a lower temperature and the depressed release of undesired
volatile byproducts are also observed in the Ni-MOFs supported AB
Effective Astaxanthin Extraction from Wet <i>Haematococcus pluvialis</i> Using Switchable Hydrophilicity Solvents
A novel
approach based on switchable hydrophilicity solvents (SHS)
was developed for extracting astaxanthin from wet microalgae. Dimethylaminocyclohexane
(DMCHA) was used to extract astaxanthin from wet Haematococcus
pluvialis, and the extraction efficiency reached 87.2%.
Astaxanthin was recovered from the DMCHA without distillation by simply
adding H<sub>2</sub>O and CO<sub>2</sub>
Microwave-Assisted Morphology Evolution of Fe-Based Metal–Organic Frameworks and Their Derived Fe<sub>2</sub>O<sub>3</sub> Nanostructures for Li-Ion Storage
The metal–organic-framework
(MOF) approach is demonstrated
as an effective strategy for the morphology evolution control of MIL-53Â(Fe)
with assistance of microwave irradiation. Owing to the homogeneous
nucleation offered by microwave irradiation and confined porosity
and skeleton by MOF templates, various porous Fe<sub>2</sub>O<sub>3</sub> nanostructures including spindle, concave octahedron, solid
octahedron, yolk–shell octahedron, and nanorod with porosity
control are derived by simply adjusting the irradiation time. The
formation mechanism for the MOF precursors and their derived iron
oxides with morphology control is investigated. The main product of
the mesoporous yolk–shell octahedron-in-octahedron Fe<sub>2</sub>O<sub>3</sub> nanostructure is also found to be a promising anode
material for lithium-ion batteries due to its excellent Li-storage
performance. It can deliver a reversible larger-than-theoretical capacity
of 1176 mAh g<sup>–1</sup> after 200 cycles at 100 mA g<sup>–1</sup> and good high-rate performance (744 mAh g<sup>–1</sup> after 500 cycles at 1 A g<sup>–1</sup>)
An investigation of inversion method to measure the radial velocity of Kuroshio from Sentinel-1 SAR data
Studies on the retrieval of ocean surface current by Synthetic Aperture Radar (SAR) mainly concentrate on coastal regions with land coverage, allowing for continuous land to estimate non-geophysical Doppler shifts. As a strong western boundary in the Western Pacific, the Kuroshio flows through mostly islands or open sea, and lacks land coverage for range bias correction. We propose a non-geophysical Doppler shift correction algorithm suitable for Kuroshio observation. Three solutions matching different land coverage were adopted in the range direction, and the scalloping was removed by using average filtering in the azimuth direction. Comparison between SAR radial velocity and Global Surface Lagrangian Drifter (GLD) reveals that the correlation coefficient (R2) increase to 0.686, and root mean square error (RMSE) of 0.215 m/s after non-geophysical corrections, while the wind-wave bias corrections make R2 increase to 0.806 and RMSE decrease to 0.13 m/s. There is also a good consistency between SAR inversion and Regional Ocean Circulation Model (ROMS). Sensitivity analysis illustrates that ascending pass is more suitable for monitoring Kuroshio, and high incidence angles are less affected by ocean conditions and non-geophysical factors. The algorithm can be used in regions with discontinuous or absent land. Three schemes for various land coverage in the range direction, including AP, IAP, and NIAP.Using average filter to remove the scalloping signal in the azimuth direction.SAR currents compared with GLD data, R2 of 0.806 and RMSE of 0.13 m/s.The method can be used in both coastal and island/offshore regions. Three schemes for various land coverage in the range direction, including AP, IAP, and NIAP. Using average filter to remove the scalloping signal in the azimuth direction. SAR currents compared with GLD data, R2 of 0.806 and RMSE of 0.13 m/s. The method can be used in both coastal and island/offshore regions.</p
Organic Nanosheets of Imide-Linked Cathodes for High-Performance Aqueous Zinc-Ion Batteries
Organic
electrodes have been identified as promising energy-storage
materials for aqueous zinc-ion batteries (AZIBs). Small molecular
materials have ideal redox properties, high specific capacity, and
structural diversity, making them a category of cathode candidates
for AZIBs. However, the instability and dissolution during the extraction
and insertion of H+/Zn2+ limit their application
of the long-cycle stability for AZIBs. Herein, a small-molecule nanosheet
(NI-DAQ, ∼14 nm in thickness) with imide linkage is designed
and synthesized by the condensation of anthraquinones and anhydrides.
It not only inhibits the dissolution of monomer electrodes but also
boosts the reactivity and conductivity of the whole molecule by the
introduction of π-conjugated imide groups and extended aromatic
planes. Therefore, the NI-DAQ electrode obtains a large initial capacity
of 191.9 mA h g–1 at 50 mA g–1 and superior cyclability after 3000 cycles at 500 mA g–1 with a minor average capacity fading rate of 0.01% per cycle. Moreover,
in situ Fourier transform infrared (FT-IR) and ex situ X-ray photoelectron
spectroscopy (XPS) characterization techniques have been implemented
to investigate the redox mechanism of CO units in AZIBs for
the NI-DAQ electrode. Thus, a promising conductive molecule is developed
and explored in this paper, which can provide insights into the application
of organic materials in AZIBs
1,25(OH)<sub>2</sub>D<sub>3</sub> Deficiency Induces Colon Inflammation via Secretion of Senescence-Associated Inflammatory Cytokines
<div><p>Epidemiological studies showed that 1,25-Dihydroxyvitamin D[1,25(OH)<sub>2</sub>D<sub>3</sub>] insufficiency appears to be associated with aging and colon cancer while underlying biological mechanisms remain largely unknown. Inflammatory bowel disease is one of the risk factors for colon cancer. In this study, we investigated whether 1,25(OH)<sub>2</sub>D<sub>3</sub> deficiency has an impact on the colon of 25-hydroxyvitamin D 1α-hydroxylase knockout [Cyp27b1<sup>−/−</sup>] mice fed on a rescue diet (high calcium, phosphate, and lactose) from weaning to 10 months of age. We found that 1,25(OH)<sub>2</sub>D<sub>3</sub> deficient mice displayed significant colon inflammation phenotypes including shortened colon length, thinned and disordered mucosal structure, and inflammatory cell infiltration. DNA damage, cellular senescence and the production of senescence-associated inflammatory cytokines were also increased significantly in the colon of Cyp27b1<sup>−/−</sup>mice. Furthermore, the levels of ROS in the colon were increased significantly, whereas the expression levels of antioxidative genes were down-regulated dramatically in the colon of Cyp27b1<sup>−/−</sup>mice. Taken together, our results demonstrated that 1,25(OH)<sub>2</sub>D<sub>3</sub> deficiency could induce colon inflammation, which may result from increased oxidative stress and DNA damage, subsequently, induced cell senescence and overproduction of senescence-associated secretory factors. Therefore, our findings suggest that 1,25(OH)<sub>2</sub>D<sub>3</sub> may play an important role in preventing the development and progression of colon inflammation and colon cancer.</p></div
Flame Retardant and Stable Li<sub>1.5</sub>Al<sub>0.5</sub>Ge<sub>1.5</sub>(PO<sub>4</sub>)<sub>3</sub>‑Supported Ionic Liquid Gel Polymer Electrolytes for High Safety Rechargeable Solid-State Lithium Metal Batteries
Recently, poor security
in conventional liquid electrolytes and
high interfacial resistance at the electrode/electrolyte interface
are the most challenging barriers for the expanded application of
lithium batteries. In this regard, easy processing and flexible composite
ionic liquid gel polymer electrolytes (ILGPEs) supported by Li<sub>1.5</sub>Al<sub>0.5</sub>ÂGe<sub>1.5</sub>Â(PO<sub>4</sub>)<sub>3</sub> (LAGP) are fabricated and investigated. The electrolyte
is effectively combined with good electrochemical performances and
thermal safety. Among these, the effects of different types of fillers
such as the inert filler-SiO<sub>2</sub> and the active filler-LAGP
on the ionic conductivity were studied in detail. LAGP particles can
not only effectively reduce the crystallinity of the polymer matrix
but also provide lithium ions and act as the lithium-ion conductor
leading to higher ionic conductivity and Li<sup>+</sup> ion transference
number. Especially, the electrolyte shows good compatibility and no
dendrite with the Li metal anode, significantly improving cyclic stability
of LiFeÂPO<sub>4</sub>/Li batteries. The results indicate that
the ILGPE-10%LAGP is a potential alternative electrolyte for high
safety rechargeable solid-state lithium metal batteries
1,25(OH)<sub>2</sub>D<sub>3</sub> deficiency induced the genes expression of the senescence-associated inflammatory cytokines.
<p>Immunohistochemical analyses of IL-1ɑ (A) IL-6 (B) IL-8 (C) HGF1 (D) MMP3 (E) expressions in the colon from the WT and Cyp27b1<sup>-/-</sup> mice. Positive cells in lamina propria were labeled by arrow. The histogram shows the mean percentage of the positive area determined from five randomly selected fields. Magnification, ×400. Bar, 25μm. Values are mean ± SEM, n = 5. *P < 0.05, ** P < 0.01. (F) Real-time RT-PCR was performed on extracts of colon from WT and Cyp27b1<sup>-/-</sup> mice for the gene expression of IL-1α, IL-1β, IL-6, IL-8, HGF1, MMP-3 and MMP-13. (G) Western blot analyses of colonic NF-κB (p105 and p50) expression in the WT and Cyp27b1<sup>-/-</sup> mice, β-actin was used as a loading control.</p