Lightweight magnesium alloys are attractive as structural materials for improving energy efficiency in applications such as weight reduction of transportation vehicles. One major obstacle for ...widespread applications is the limited ductility of magnesium, which has been attributed to Formula: see text dislocations failing to accommodate plastic strain. We demonstrate, using in situ transmission electron microscope mechanical testing, that Formula: see text dislocations of various characters can accommodate considerable plasticity through gliding on pyramidal planes. We found that submicrometer-size magnesium samples exhibit high plasticity that is far greater than for their bulk counterparts. Small crystal size usually brings high stress, which in turn activates more Formula: see text dislocations in magnesium to accommodate plasticity, leading to both high strength and good plasticity.
Abstract
Conventional ultrafine-grains can generate high strength in Mg alloys, but significant tradeoff of corrosion resistance due to inclusion of a large number of non-equilibrium grain ...boundaries. Herein, an ultrafine-grain structure consisting of dense ultrafine twins is prepared, yielding a high strength up to 469 MPa and decreasing the corrosion rate by one order of magnitude. Generally, the formation of dense ultrafine twins in Mg alloys is rather difficult, but a carefully designed multi-directional compression treatment effectively stimulates twinning nucleation within twins and refines grain size down to 300 nm after 12-passes compressions. Grain-refinement by low-energy twins not only circumvents the detrimental effects of non-equilibrium grain boundaries on corrosion resistance, but also alters both the morphology and distribution of precipitates. Consequently, micro-galvanic corrosion tendency decreases, and severe localized corrosion is suppressed completely. This technique has a high commercial viability as it can be readily implemented in industrial production.
Design and development of highly efficient photocatalytic materials are key to employ photocatalytic technology as a sound solution to energy and environment related challenges. This work aims to ...significantly boost photocatalytic activity through rich indium vacancies (VIn) In2S3 with atomic p–n homojunction through a one‐pot preparation strategy. Positron annihilation spectroscopy and electron paramagnetic resonance reveal existence of VIn in the prepared photocatalysts. Mott–Schottky plots and surface photovoltage spectra prove rich VIn In2S3 can form atomic p–n homojunction. It is validated that p–n homojunction can effectively separate carriers combined with photoelectrochemical tests. VIn decreases carrier transport activation energy (CTAE) from 0.64 eV of VIn‐poor In2S3 to 0.44 eV of VIn‐rich In2S3. The special structure endows defective In2S3 with multifunctional photocatalysis properties, i.e., hydrogen production (872.7 µmol g−1 h−1), degradation of methyl orange (20 min, 97%), and reduction in heavy metal ions Cr(VI) (30 min, 98%) under simulated sunlight, which outperforms a variety of existing In2S3 composite catalysts. Therefore, such a compositional strategy and mechanistic study are expected to offer new insights for designing highly efficient photocatalysts through defect engineering.
Rich indium vacancies (VIn) In2S3 are constructed with atomic p–n homojunction for boosting photocatalytic multifunctional properties. The formation of defects and atomic p–n homojunction accelerates carrier separation and migration efficiency. Therefore, such a compositional strategy offers new insights for designing highly efficient atomic p–n homojunction photocatalysts through defect engineering.
We investigate the close connection between the quantum phase space Wigner distribution of small-x gluons and the color dipole scattering amplitude, and we propose studying it experimentally in the ...hard diffractive dijet production at the planned electron-ion collider. The angular correlation between the nucleon recoiled momentum and the dijet transverse momentum probes the nontrivial correlation in the phase space Wigner distribution. This experimental study not only provides us with three-dimensional tomographic pictures of gluons inside high energy protons-it gives a unique and interesting signal for the small-x dynamics with QCD evolution effects.
Competing inhomogeneous orders are a central feature of correlated electron materials, including the high-temperature superconductors. The two-dimensional Hubbard model serves as the canonical ...microscopic physical model for such systems. Multiple orders have been proposed in the underdoped part of the phase diagram, which corresponds to a regime of maximum numerical difficulty. By combining the latest numerical methods in exhaustive simulations, we uncover the ordering in the underdoped ground state. We find a stripe order that has a highly compressible wavelength on an energy scale of a few kelvin, with wavelength fluctuations coupled to pairing order. The favored filled stripe order is different from that seen in real materials. Our results demonstrate the power of modern numerical methods to solve microscopic models, even in challenging settings.
•MOF nanoparticles are assembled on the bacterial cellulose by weak interaction.•MOF aerogels with hierarchical structures are flexible and lightweight.•BC@ZIF-8 demonstrates an excellent adsorption ...performance of heavy metal ions.•BC@UiO-66@PDA interlayer can improve the performance of Li-S batteries.
Flexible metal-organic framework (MOF) aerogels with practical macroscopic shapeability and hierarchical porosity were prepared through in-site growth of MOF nanoparticles, i.e. zeolitic imidazolate framework-8 (ZIF-8) and University of Oslo-66 (UiO-66), on bacteria cellulose (BC). The yielded composite aerogels inherit high porosities from feedstock MOFs and mechanical flexibility from BC template. BC template offers high porosity, mechanical flexibility to the composite aerogels, which significantly suppresses the aggregation of individual MOF nanoparticles. Owing to the structural characteristics of MOF and BC, BC@ZIF-8 composite aerogel sponges exhibit a low density below 0.03 g cm−3, hierarchical porosity, large surface area, high mass transfer efficiency and superior adsorption performance of heavy metal ions. After 24 h adsorption in simulated industrial waterwastes, removal efficiency of the composite aerogels reaches up to 81% with respect to Pb2+ ion pollutants, which is 1.2 times higher than that of original ZIF-8 nanoparticle counterparts. BC@UiO-66 composite aerogel film, as a flexible lithium-sulfur battery interlayer, demonstrates a high reversible capacity of 631 mAh g−1 at 0.5C over 100 cycles, which is attributed to its selectivity for Li+ ions and efficient inhibition to the soluble polysulfide ions. In addition, the presence of polydopamine (PDA) coating on BC@UiO-66 nanofibers in BC@UiO-66@PDA composite aerogel films increases reversible capacity up to 739 mAh g−1 at 0.5 C over 100 cycles. This work provides a feasible solution to process MOF powders into a flexible and tailorable form, and holds a new promise to rational design and manufacturing of MOF monoliths with a great structural diversity as advanced multifunctional materials.
Highlights
Ultralight 3D NiCo compound@MXene nanocomposites that inherited hollow polyhedral skeleton and excellent conductive network were fabricated.
Excellent electromagnetic absorption ...performance was achieved with optimal RLmin value of − 67.22 dB and ultra-wide EAB of 6.72 GHz under the low filler loading.
Electromagnetic parameters and microwave absorption property can be distinctly or slightly regulated by adjusting the filler loading and decoration of Ti
3
C
2
T
x
nanoflakes.
The 3D hollow hierarchical architectures tend to be designed for inhibiting stack of MXene flakes to obtain satisfactory lightweight, high-efficient and broadband absorbers. Herein, the hollow NiCo compound@MXene networks were prepared by etching the ZIF 67 template and subsequently anchoring the Ti
3
C
2
T
x
nanosheets through electrostatic self-assembly. The electromagnetic parameters and microwave absorption property can be distinctly or slightly regulated by adjusting the filler loading and decoration of Ti
3
C
2
T
x
nanoflakes. Based on the synergistic effects of multi-components and special well-constructed structure, NiCo layered double hydroxides@Ti
3
C
2
T
x
(LDHT-9) absorber remarkably achieves unexpected effective absorption bandwidth (EAB) of 6.72 GHz with a thickness of 2.10 mm, covering the entire Ku-band. After calcination, transition metal oxide@Ti
3
C
2
T
x
(TMOT-21) absorber near the percolation threshold possesses minimum reflection loss (RL
min
) value of − 67.22 dB at 1.70 mm within a filler loading of only 5 wt%. This work enlightens a simple strategy for constructing MXene-based composites to achieve high-efficient microwave absorbents with lightweight and tunable EAB.
A key issue for perovskite solar cells is the stability of perovskite materials due to moisture effects under ambient conditions, although their efficiency is improved constantly. Herein, an improved ...CH3NH3PbI3−xClx perovskite quality is demonstrated with good crystallization and stability by using water as an additive during crystal perovskite growth. Incorporating suitable water additives in N,N‐dimethylformamide (DMF) leads to controllable growth of perovskites due to the lower boiling point and the higher vapor pressure of water compared with DMF. In addition, CH3NH3PbI3−xClx · nH2O hydrated perovskites, which can be resistant to the corrosion by water molecules to some extent, are assumed to be generated during the annealing process. Accordingly, water additive based perovskite solar cells present a high power conversion efficiency of 16.06% and improved cell stability under ambient conditions compared with the references. The findings in this work provide a route to control the growth of crystal perovskites and a clue to improve the stability of organic–inorganic halide perovskites.
Water additive is incorporated into the perovskite precursor solution to control the oriented growth of crystal perovskites and improve the stability of perovskite solar cells. As a result, a power conversion efficiency of 16.06% and an improved cell stability under ambient conditions are achieved.
Herein we report two new TPE‐based 3D MOFs, that is, Sr‐ETTB and Co‐ETTB (TPE=Tetraphenylethylene, H8ETTB=4′,4′′′,4′′′′′,4′′′′′′′‐(ethene‐1,1,2,2‐tetrayl)tetrakis((1,1′‐biphenyl‐3,5‐dicarboxylic ...acid))). Through tailoring outer shell electron configurations of SrII and CoII cations, the fluorescence intensity of the MOFs is tuned from high emission to complete non‐emission. Sr‐ETTB with strong blue fluorescence shows reversible fluorescence variations in response to pressure and temperature, which is directly related to the reversible deformation of the crystal structure. In addition, non‐emissive Co‐ETTB counterpart exhibits a turn‐on fluorescent enhancement under the stimulation of analyte histidine. In the process, TPE‐cored linkers in the MOFs are released through competitive coordination substitution and subsequently reassembled to perform aggregation‐induced luminescence behavior originated from the organic linkers.
Two new tetraphenylethylene‐based 3D MOFs are obtained. Sr‐ETTB performs uncommon reversible thermo/piezofluorochromism and thermo/piezochromic behaviors which are driven by its characteristic crystalline framework flexibility. Non‐emissive Co‐ETTB exhibits a turn‐on fluorescent enhancement under the stimulation of analyte histidine.
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