Lithium metal is a promising anode material for high energy density batteries, which is restricted from practical application by the issues including lithium dendrite, parasitic reaction and ...volumetric change. Herein, a strategy combing bulk and surface modification is proposed to address these problems. The bulk modification is to use Ni foam as three dimensional (3D) scaffold for direct infusion of molten Li resulting in the formation of Li-Ni composite anode, which reduces actual current density by increasing specific surface area and alleviates volumetric change in the process of Li stripping/plating. And the surface modification is to coat with ZnF2 film via sputtering, which is acted as artificial protective layer for controlling interfacial side reaction. The symmetric cell consisting of ZnF2 coated Li-Ni composite electrodes exhibits low overpotential (about 45 mV) and stable cycling over 900 h at 1 mA cm−2. Furthermore, the cell with LiCoO2 cathode delivers 110 mAh g−1 at 1 C rate after 500 cycles.
Li anode with surface and bulk modification was fabricated by infusion of molten Li into Ni foam and coating with ZnF2 film. The surface modified Li-Ni composite electrode demonstrates excellent electrochemical performance since the surface modification reduces interfacial side reaction and three dimensional Ni scaffold suppresses the growth of Li dendrite. Display omitted
•The strategy of both bulk and surface modification is proposed for suppressing lithium dendrite.•Surface modification with ZnF2 film as artificial SEI reduces interfacial side reaction.•The excellent performance (stable cycling for 600 cycles) of symmetric cell was achieved at extreme current density.
The preparations of crystal titanium dioxide (TiO₂) are often time-consuming multistep processes involving high temperature. Rapid and efficient methods to obtain TiO₂ with anatase or rutile phase ...are desirable. In this paper, we describe an ultrafast single-step method to obtain urchin-like rutile TiO₂ particles via microwave irradiation. In the procedure, TiCl₄ aqueous solution was used as a reactant and toluene was used as a solvent. It takes only a few minutes without any further heat treatment. The samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The effect of temperature, irradiation time and the ratio of precursor to solvent on the morphology and crystal structure were studied. The results show urchin-like rutile TiO₂ with high stability is formed after only 5 min microwave irradiation at 135 °C.
The characteristics of underwater acoustic channel such as long propagation delay and low bit rate cause the MAC (Medium Access Control) protocols designed for radio channels to be either ...inapplicable, or have low efficiency for UWSN (Underwater Sensor Network). We propose a hierarchical and distributed code assignment algorithm based on divisive probability function which can avoid conflict between spread codes with high probability, and provide a state-based MAC protocol for UWSN. Without RTS/CTS (Request To Send/Clear To Send) handshaking, each node maintains a neighbor table including state field, and packages are forwarded according to the state of the receiver, so it can avoid the interference caused by transmitting to a sending node in a half-duplex system and improve channel utilization. The design of power control minimizes the near-far effect inherent in CDMA. Simulation results reveal that state-based CDMA protocol shows outstanding performance in throughput, delivery ratio and resource-consumption.
Polyethylene oxide (PEO)-salt complex is an important polymer electrolyte-based anhydrous electrorheological (ER) material. However, it is difficult to get PEO-based ER material in particle form ...owing to the low glass transition temperature. Cross-linking and copolymerization with other polymers are widely used ways to form polyether-salt complex with desired dimensions and stability. However, these ways are relatively complex, and the ionic conductivity of resulting products is also too high for ER application. In this paper, we report a simple way to form PEO-based nanocomposite ER particles by intercalation chemistry with montmorillonite (PEO-MMT) under the help of ethanol solvent. The structure and composition of samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry, and so on. An increase in basal d001-spacings demonstrates successful intercalation of PEO in MMT. The electro-responsive ER effect of PEO-MMT suspension under electric fields was studied. It demonstrated that PEO intercalation not only effectively solved the problem of difficult granulation of PEO ER material but also replaced the absorbed water in the interlayer of MMT and greatly limited the ionic conductivity of MMT. Under electric fields, the suspension of PEO-MMT nanocomposite was found to show significant ER effect, weak current density, and wide working temperature range. A significant interfacial polarization process was observed by dielectric spectra measurement, which can explain the significant ER effect of PEO-MMT nanocomposite.
Display omitted
•PEO-MMT nanocomposite were prepared by intercalation chemistry.•PEO intercalation effectively solved difficult granulation of PEO.•PEO replaced water in MMT and limited conductivity of MMT.•PEO-MMT suspension showed enhanced ER effect.•PEO-MMT showed significant interfacial polarization process.
Purpose
This work aims to develop an approach for simultaneous water–fat separation and myocardial T1 and T2 quantification based on the cardiac MR fingerprinting (cMRF) framework with rosette ...trajectories at 3T and 1.5T.
Methods
Two 15‐heartbeat cMRF sequences with different rosette trajectories designed for water–fat separation at 3T and 1.5T were implemented. Water T1 and T2 maps, water image, and fat image were generated with B0 inhomogeneity correction using a B0 map derived from the cMRF data themselves. The proposed water–fat separation rosette cMRF approach was validated in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI system phantom and water/oil phantoms. It was also applied for myocardial tissue mapping of healthy subjects at both 3T and 1.5T.
Results
Water T1 and T2 values measured using rosette cMRF in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology phantom agreed well with the reference values. In the water/oil phantom, oil was well suppressed in the water images and vice versa. Rosette cMRF yielded comparable T1 but 2~3 ms higher T2 values in the myocardium of healthy subjects than the original spiral cMRF method. Epicardial fat deposition was also clearly shown in the fat images.
Conclusion
Rosette cMRF provides fat images along with myocardial T1 and T2 maps with significant fat suppression. This technique may improve visualization of the anatomical structure of the heart by separating water and fat and could provide value in diagnosing cardiac diseases associated with fibrofatty infiltration or epicardial fat accumulation. It also paves the way toward comprehensive myocardial tissue characterization in a single scan.
This work aims to develop an approach for simultaneous water-fat separation and myocardial T
and T
quantification based on the cardiac MR fingerprinting (cMRF) framework with rosette trajectories at ...3T and 1.5T.
Two 15-heartbeat cMRF sequences with different rosette trajectories designed for water-fat separation at 3T and 1.5T were implemented. Water T
and T
maps, water image, and fat image were generated with B
inhomogeneity correction using a B
map derived from the cMRF data themselves. The proposed water-fat separation rosette cMRF approach was validated in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology MRI system phantom and water/oil phantoms. It was also applied for myocardial tissue mapping of healthy subjects at both 3T and 1.5T.
Water T
and T
values measured using rosette cMRF in the International Society for Magnetic Resonance in Medicine/National Institute of Standards and Technology phantom agreed well with the reference values. In the water/oil phantom, oil was well suppressed in the water images and vice versa. Rosette cMRF yielded comparable T
but 2~3 ms higher T
values in the myocardium of healthy subjects than the original spiral cMRF method. Epicardial fat deposition was also clearly shown in the fat images.
Rosette cMRF provides fat images along with myocardial T
and T
maps with significant fat suppression. This technique may improve visualization of the anatomical structure of the heart by separating water and fat and could provide value in diagnosing cardiac diseases associated with fibrofatty infiltration or epicardial fat accumulation. It also paves the way toward comprehensive myocardial tissue characterization in a single scan.
Cardiovascular magnetic resonance is a versatile tool that enables noninvasive characterization of cardiac tissue structure and function. Parametric mapping techniques have allowed unparalleled ...differentiation of pathophysiological differences in the myocardium such as the delineation of myocardial fibrosis, hemorrhage, and edema. These methods are increasingly used as part of a tool kit to characterize disease states such as cardiomyopathies and coronary artery disease more accurately. Currently conventional mapping techniques require separate acquisitions for T
and T
mapping, the values of which may depend on specifics of the magnetic resonance imaging system hardware, pulse sequence implementation, and physiological variables including blood pressure and heart rate. The cardiac magnetic resonance fingerprinting (cMRF) technique has recently been introduced for simultaneous and reproducible measurement of T
and T
maps in a single scan. The potential for this technique to provide consistent tissue property values independent of variables including scanner, pulse sequence, and physiology could allow an unbiased framework for the assessment of intrinsic properties of cardiac tissue including structure, perfusion, and parameters such as extracellular volume without the administration of exogenous contrast agents. This review seeks to introduce the basics of the cMRF technique, including pulse sequence design, dictionary generation, and pattern matching. The potential applications of cMRF in assessing diseases such as nonischemic cardiomyopathy are also briefly discussed, and ongoing areas of research are described.
The development of multispectral detection emphasizes the significance of multispectra‐compatible camouflage technology, necessitating compatible camouflage for visible and infrared bands. ...Conventional painted camouflage is hindered by high infrared emissivity, and crafting patterns with existing low‐emissivity materials is hindered by the lack of adequate colors. Herein, this study introduces a method to reduce the emissivity while maintaining its original color. By covering a metafilm that reflects most infrared radiation on conventional patterned camouflage, low‐emissivity coatings are achieved. The thickness of the metafilm is optimized, effectively reducing color differences between uncoated and coated camouflage. Monochromatic substrates with the metafilm retain original colors with small color differences (e.g., 0.61) and demonstrate low infrared emissivity (0.03). Patterned camouflage yields an area‐weighted color difference of 9.09 with an infrared emissivity of 0.05. Experimental application on grassland backgrounds demonstrates visual integration with the background. Infrared thermography shows that coated camouflages, compared to uncoated ones, exhibits significantly reduced radiant temperature (29.5 °C vs. 43.0 °C) when heated to 50 °C against a 29.5 °C background, enhancing its blending capability. This metafilm effectively mitigates infrared emissivity while maintaining original colors and patterns, facilitating efficient camouflage across visible and infrared spectrums.
To address challenges posed by multispectral detection, an approach to visible‐infrared camouflage is proposed. This involves applying a multilayer metafilm onto patterned camouflage. The metafilm is designed by minimizing the color difference between uncoated and coated patterns and reserving low infrared emissivity. Consequently, this method effectively conceals objects in both visible and infrared spectra.
Solvent-free double network elastomers have excellent mechanical properties and stability. However, there are few studies on ion transport in solvent-free double network elastomers. In this paper, we ...prepared a kind of poly(ionic liquid) (PIL)-based solvent-free elastomer with double network structure by using crosslinked poly2-(methacryloyloxy)ethyl trimethyl ammonium bis(trifluoromethanesulfonyl) imine (PVBTMATFSI) network as brittle network and crosslinked poly(ethyl acrylate) (PEA) as stretchable network. The mechanical properties and the ion transport of samples as a function of elongation strain were investigated by stress-strain curves and broadband dielectric spectroscopy, respectively. The results show the double network elastomer has medium elastic modulus of 0.4–0.9 MPa, high elongation strain of 1700–2300% and ionic conductivity of 1.04 × 10−7 S·m−1 at room temperature. When the sample does not yield, stretching almost does not affect the ion transport in the network. As the strain exceeds the yield point, the conductivity relaxation time of the samples with low crosslinking degree of PIL network increases little, while the conductivity relaxation time of the samples with high crosslinking degree increases significantly. This is because the former network breaks uniformly, while the latter appears phase separation when yielding. The result improves the understanding of ion transport in double network polyelectrolyte elastomers.
Solvent-free DN elastomers composed of PIL/PEA are prepared, which show medium elastic modulus and high elongation strain. Stretching does not affect ion transport in the DN elastomers before yield, while stretching affects ion transport in the DN elastomers after yield due to phase separation. Display omitted
•Solvent-free DN elastomers composed of PIL/PEA are prepared.•The DN elastomer has medium elastic modulus and high elongation strain.•Stretching does not affect ion transport in the DN elastomers before yield.•Stretching affects ion transport in the DN elastomers after yield due to phase separation.
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