This paper investigates the damage pattern of the concrete lining in a large-diameter subsea shield tunnel under different seismic loading intensities. Based on the Shantou Bay (STB) Tunnel, a ...refined finite element (FE) model consisting of “1/2 + 1+1/2” liner-rings is established in the study. In addition, another FE model considering both the strata and lining is created to obtain the seismic displacement-time history, which is employed as the boundary conditions on the “1/2 + 1+1/2” liner-rings model. A whole-ring model is thereafter generated considering the segment details, adopting the Concrete Damage Plastic (CDP) constitutive assumption and artificial viscoelastic boundary. An improved reaction-displacement method based on the concept of the “equivalent layer” is proposed to consider stratum-structure interaction. Finally, two types of seismic intensities and three work conditions are employed to investigate the influence on lining segments and joint openings. The results show that: (i) the damage to the segment of the shield tunnel is mainly concentrated in the top and bottom of the arch and the outer area of the waist under seismic loading; (ii) the moment of a sudden change in the damage development trend and the joint opening is related to the peak response of seismic time history; (iii) the segments of the shield tunnel are dominated by vertical oval shape deformation under a horizontal earthquake, and dominated by horizontal oval shape deformation under a vertical earthquake; (iv) the area and level of lining damage increase with the development of the earthquake intensity.
•The damage pattern of a large-diameter subsea shield-tunnel under different seismic intensities is investigated.•A series of refined FE models are established in the study considering the segmentation and assembly of the tunnel lining.•An improved reaction-displacement method based on the concept of the “equivalent layer” is proposed.
Heterojunctions of Ta
O
and multiwalled carbon nanotubes (MWCNTs) have been successfully synthesized by a facile and cost-effective hydrothermal method, with a super thin and uniform Ta
O
shell ...wrapped around the MWCNT. The combination of Ta
O
and MWCNTs at the interface not only modifies the morphology but also forms the p-n heterojunction, which contributes to the reconstruction of band structure, as well as the low resistance of matrix and highly chemisorbed oxygen content. The Ta
O
@MWCNT p-n heterojunction exhibits ultrasensitive performance to ethanol at room temperature, with a response of 3.15 toward 0.8 ppm ethanol and a detection limit of 0.173 ppm. The sensor has a high reproducibility at various concentrations of ethanol, superior selectivity to other gases, and long-term stability. The strategy of hybriding metal oxide semiconductors with MWCNT promises to provide a feasible and further developable pathway for high-performance room-temperature gas sensors.
Abstract
Layered transition metal dichalcogenides have great potential as anodes of sodium‐ion batteries (SIBs) due to their high theoretical specific capacity. However, the restacking severely ...limits their accessible sites, leading to undesirable specific capacity, cycle stability, and working temperature range. Herein, a hierarchical 2D VS
2
/Ti
3
C
2
T
x
MXene hybrid is designed via a simple liquid‐mixing method, where VS
2
is confined in the conductive Ti
3
C
2
T
x
matrix with chemical connections built between them. The in situ transmission electron microscopy analyses reveal that the hybrid depends on a very fast and reversible intercalation/de‐intercalation process between VS
2
and Na
x
VS
2
(where
x
= 1) to store sodium. Theoretical calculations disclose that the Ti
3
C
2
T
x
matrix remarkably enhances the charge transfer and alleviates the volume expansion of VS
2
especially after Na
+
is inserted. Consequently, such a rational design exhibits an intercalation pseudocapacitance‐dominant mechanism, with excellent specific capacity (522 mAh g
−1
at 0.2 A g
−1
), rate capability (342 mAh g
−1
at 10 A g
−1
), cycle life (116% after 3000 cycles), and also all‐climate workability (with high specific capacity and long‐term cycle stability even at 70 and −40 °C). This study may open up a new vision to design fast‐charging, long‐cycle, and all‐climate SIBs anodes based on the intercalation pseudocapacitance.
•Rotten egg album was used to fabricate nitrogen-doped layered carbon (REAC).•The conductive REAC improves Li+ diffusion coefficient and electronic conductivity.•The LSBs with REAC PP separator ...exhibit decay rate of 0.055% per cycle in 400 cycles.
Lithium–sulfur batteries (LSBs) with high energy density and high specific capacity are considered promising rechargeable energy devices. However, the capacity attenuation caused by “shuttle effect” hinders their practical application. In this work, layered rotten egg albumen carbon (REAC) was fabricated via freezing dry and carbonization methods to enhance capacity retention of LSBs. The LSBs with REAC modified polypropylene (REAC PP) separator exhibit the following superior electronical performances: (1) the conductive REAC improves lithium ion (Li+) coefficient by increasing the electrical conductivity; (2) the nitrogen-doped sites in REAC enhances polysulfide adsorption and increases the electronic conductivity; (3) the compact layered structure inhibits the “shuttle effect” of polysulfides and enhance electrochemical performance. The LSBs with REAC PP separator and 72 wt% sulfur deliver an initial capacity of 1092.8 mA h g−1 at 0.1C. Also, such LSBs exhibit capacity of 633.8 mA h g−1 at 1C with low decay rate of 0.055% per cycle in 400 cycles. Considering the waste recycling, simple synthesis and enhanced electrochemical performance, REAC PP separator is promising for LSBs.
Abstract
Although coating technology and in‐situ synthesis have been widely applied to produce Fe
3
O
4
NPs‐containing composite materials, there still exist potential risks to the environment. ...Herein, an eco‐friendly preparation of Fe
3
O
4
nanoparticles (FNPs)‐coated wool felt is proposed based on the self‐glue effect of wool keratins in the NaHSO
3
/urea solution. It avoids the use of coating agents, and also the commercially available FNPs are directly utilized as raw materials, both making the residual FNPs completely recyclable. The resulting FNPs‐coated wool felt shows high magnetization (23.54 emu g
−1
) and excellent microwave‐assisted heating properties (the temperature rise is about 40°C after 10 min). The results of EDS‐SEM (energy dispersive spectrometer‐scanning electron microscope), loud amount (%), crease recovery angle (CRA), Fourier transform infrared (FTIR) spectrometer and X‐ray diffraction (XRD) prove that the dramatical swelling and the recoagulation of superficial keratins of wool fibers are the mechanism of the self‐glue effect.
Magnetic nanoparticles were synthesized and embedded into the surface of cotton fibers via surface micro-dissolution method using NaOH/urea aqueous solution as dissolving agent, magnetic ...nanoparticles as the filler, and H
2
SO
4
/Na
2
SO
4
aqueous solution as the coagulant. The magnetic nanoparticles and cotton fabrics were systematically studied by means of scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, thermal gravity, vibrating sample magnetometry, Fourier transform infrared spectroscopy, and tensile testing. The results indicated that treated cotton fabrics contained about 12 wt% Fe
3
O
4
and possessed durable magnetic response. Without using any adhesion agents, this surface micro-dissolution treatment provides a simple and green method to introduce nanoparticles into superficial layers of natural cotton fibers.
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•Surface micro-dissolution method was proposed to introduce polyaniline to polyester textiles.•The preparation was easy to perform, which was carried out at 70 ℃ for 15 min.•Resulting ...textiles show good electrical and electrothermal performances.•Resulting textiles were assembled into flexible electrodes and showed high electric capacity.
Incorporation of PANI with polyethylene terephthalate (PET) fibers has creates many flexible conductive, electrothermal and energy-storage textiles. The most common method of depositing PANI to PET fibers is in-situ polymerization. However, it usually needs long reaction time and strict conditions, which is unbeneficial to large-scale commercialized process. Herein, a facile and high-efficiency surface micro-dissolution method was proposed to prepare PANI-coated PET fabrics, which is performed at moderate temperature (70 °C) and only needs 15 min of treatment time. Already-made PANI powders were directly used as raw materials, and the phenol/N-methyl pyrrolidone (phenol/NMP) solution worked as the surface micro-dissolution agent. The resulting fabrics show electroconductive (620 Ω/□), electrothermal (from 22.3–30.3 ℃ within 1 min) and energy storage (438.51 m F cm−2) performances. The preparation is easy to perform and of very high efficiency, making it suitable for industrial production of PANI-coated PET fabrics.
Fe3O4 nanoparticles were embedded into the surface of silk fibers for preparing effectively magnetic silk fabrics. Fe3O4 nanoparticles were applied onto silk fabrics by a swelling-fixing method in ...presence of the aqueous solution of ethylenediamine tetraacetic acid disodium salt (EDTA-2Na) and urea as swelling agent and the low concentration glutaraldehyde solution as fixing agent. The magnetic silk fabrics and raw silk fabrics were characterized by measuring X-Ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscope (SEM). The results confirmed that magnetic silk fabrics could be successfully obtained by a swelling-fixing method and the crystalline structure of silk wasn't seriously destroyed. The similar thermogravimetric curves and breaking strength showed that thermal stability and mechanical properties of treated fabrics were also highly preserved. Moreover, the magnetic properties and wash fastness of samples were also studied. It suggested treated silk fabrics had effective magnetic property, and the magnetizations decreased by 14.58% after multiple washing.
•An effective way for fabricating magnetic silk fabrics by a swelling-fixing method.•Nanoparticles were embedded in the surface of silk fibers by swelling and fixing proteins without using any adhesion agents.•Magnetic silk fabrics exhibited excellent laundering durability.•The inherent thermal stability and mechanical properties of silk fabrics were highly preserved after they were treated.
