Lithium (Li) metal anodes have shown a huge potential for next-generation energy storage because of the high theoretical specific capacity and negative potential. Nevertheless, due to the change in ...the volume and the existence of Li dendrites, the application of the Li metal anode is significantly limited. For the purpose of developing a stable Li metal anode to avoid Li dendrite formation, we introduced a stable artificial solid electrolyte interphase (SEI) film, which was prepared by polyvinyl alcohol (PVA) cementing a metal organic framework (Zn-MOF). The environment-friendly and non-toxic PVA acted as a “glue” to cement the rigid Zn-MOF. The artificial SEI film had high Li ion conductivity and excellent flexibility, which is beneficial for uniform lithium flux, inhibiting dendrite growth and easing the volume change. Consequently, benefitting from the safeguard of the Zn-MOF/PVA artificial SEI film, the anode delivered high coulombic efficiency above 97.7% beyond 250 cycles at a current density of 3 mA cm −2 .
•The function mechanism of DLPS is explored.•Deformation transferring path, working state, and failure modes are analyzed.•The mechanical model was established and deformation expressions were ...obtained.•Engineering design principles were proposed.
The Dongping No.1 Tunnel of the Guangdong–Foshan Loop Line Intercity Railway in China passes an existing large-scale underground pipe gallery in water-rich sandy strata through the undercutting method. During construction, controlling the underground pipe gallery deformation is difficult because the water-rich sandy strata can easily become unstable. To deal with this problem, this paper proposes a double layer pre-support system (DLPS) consisting of pipe shed and horizontal jet grouting piles, whose function mechanism is explored from the viewpoint of passive protection and active reinforcement. The deformation transferring path of the DLPS is described as follows: tunnel excavation → lower pre-support deformation → deformation of the soil between the upper and the lower pre-supports → upper pre-support deformation → underground pipe gallery deformation. Considering the influence of geological conditions, the proposed DLPS has two failure modes, namely, excessive settlement of the tunnel vault and excessive deformation of the overlying underground pipe gallery. The mechanical model and analytical method of the DLPS were established according to the theory of beam resting on elastic foundation. Comparing the computed and measured settlement values revealed that the established model is reliable because it could reflect the interaction characteristics of the upper pre-support, the lower pre-support, and the middle soil. Finally, multiple factor analysis was conducted to ascertain the influence of typical calculating parameters, and the deformation characteristics of the DLPS under different influence factors were obtained. The design suggestions for key parameters could provide reference for similar practical engineering in the future.
The emerging thermally activated delayed fluorescence materials have great potential for efficiencies in organic light-emitting diodes by optimizing molecular structures of the emitter system. ...However, it is still challenging in the device structural design to achieve high efficiency and stable device operation in white organic light-emitting diodes. Here we propose a universal design strategy for thermally activated delayed fluorescence emitter-based fluorescent white organic light-emitting diodes, establishing an advanced system of "orange thermally activated delayed fluorescence emitter sensitized by blue thermally activated delayed fluorescence host" combined with an effective exciton-confined emissive layer. Compared to reference single-layer and double-layer emissive devices, the external quantum efficiency improves by 31 and 45%, respectively, and device operational stability also shows nearly fivefold increase. Additionally, a detailed optical simulation for the present structure is made, indicating the validity of the design strategy in the fluorescent white organic light-emitting diodes.
The sluggish kinetics and large volume expansion arising from the large ionic radius of Na+ remain elusive weaknesses of sodium ion batteries (SIBs). Here, we report a transition from bulk diffusion ...to surface-dominant pseudocapacitive charge storage by nanoscaling and heterostructuring, which enables fast and stable charge storage kinetics for SIBs. An electronic attraction induced self-assembly strategy was developed for the synthesis of the 1T/2H MoS2@SnO2 heterostructure. Ultrasmall SnO2 nanoparticles with a low crystallinity were uniformly distributed on the basal plane of MoS2. The intercalated SnO2 serves as an interfacial pillar to restrict the restacking of MoS2 nanosheets, whereas dual-phase 1T/2H MoS2 provides a continuous network for efficient charge transfer and restrains the aggregation of NaxSn. As a result, the 1T/2H MoS2@SnO2 heterostructure exhibits a higher specific capacity (626 mA h g−1 at 0.1 A g−1), and superior cycling and rate capabilities (262 mA h g−1 at 2 A g−1 for 500 cycles) compared to the raw MoS2 and 2H MoS2@SnO2 counterparts. Electrochemical kinetics analyses reveal that the charge transfer kinetics are boosted by the synergistic effect between the 1T/2H MoS2 and SnO2 nanoparticles. Quantitative examination into the origin demonstrated that the Na+ storage is dominated by the fast surface redox reaction, which endows the heterostructure with a durable high rate capability.
The deformation resistance would be increased with the addition of Nb and Ti, which makes it difficult to accurately control the rolling process, resulting in mixed grains and cracks. The hot ...deformation behavior of Nb–Ti microalloyed high strength steel was investigated in the temperature range of 900–1100 °C with the strain rate between 0.1 and 5 s−1. The recrystallization active energy was obtained by regression calculation, and the thermal deformation equation was established. The dynamic recrystallization critical strain model was established by changing the work hardening rate. The results show that a higher deformation temperature and lower strain rate are conducive to dynamic recrystallization. The active energy of dynamic recrystallization is 386.30 kJ mol−1, εp = 1.23 × 10−2 Z0.087, and εc = 1.95 × 10−3 Z0.111. The high strength steel is strengthened by the strengthening of grain refining and precipitation of Nb–Ti microalloys. The second phase particles are TiN with a size of about 100 nm, (Nb, Ti)C with the size between 50 and 80 nm, and NbC with the size between 10 and 20 nm.
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•TTA-UC is first integrated with photocatalyst by the detergent-free microemulsion.•High TTA-UC efficiency and high utilization efficiency of UC emission are realized in ...microemulsion.•The best performance for TTA-UC integrated photocatalytic systems for H2 evolution is achieved.
To enhance the light-harvesting ability of photocatalytic splitting water system, triplet–triplet annihilation upconversion (TTA-UC) is integrated with photocatalysis directly for the first time via a detergent-free ternary toluene/isopropanol/water microemulsion system. TTA-UC pairs containing PtOEP/PdTPTBP/PdTPNEt2P and perylene are combined with Cd0.5Zn0.5S for photocatalytic hydrogen production. These TTA-UC pairs convert visible light with the wavelength >510 nm that cannot be absorbed directly by Cd0.5Zn0.5S into blue light with smaller wavelength. Cd0.5Zn0.5S is then sensitized by this upconverted blue light to produce hydrogen. More importantly, the hydrogen production rate (8.44 mmol g-1h−1) of this integrated photocatalytic system is twice as high as that of the pure Cd0.5Zn0.5S microemulsion (4.04 mmol g-1h−1) under visible light (λ > 420 nm) irradiation, which is the best performance for the TTA-UC integrated photocatalytic system for hydrogen evolution ever reported so far. The high upconversion efficiency and high utilization efficiency of upconversion emission in microemulsion are responsible for the significantly promoted catalytic performance of this integrated photocatalytic system. The result demonstrates a simple strategy to integrate TTA-UC with photocatalyst for enhancing the hydrogen production efficiency. Considering the easily-tunable excitation/emission wavelength of TTA-UC pairs, this method could be used to integrate TTA-UC with a variety of photocatalysts.
Quasi two-dimensional (2D) lead halide perovskite materials have shown outstanding performance in various photoelectric devices, including perovskite light-emitting diodes (LEDs) and perovskite ...optical pumping lasers. Due to the structure diversity of bulky organic cation, the photoelectric property for quasi-2D perovskite materials is flexible to be tuned. The spontaneously formed quantum-well structures allow rapid and efficient energy funneling from low-
domains to high-
domains, contributing to high exciton utilization for perovskite LEDs and low threshold for amplified spontaneous emission (ASE) and optical pumping perovskite lasers. Moreover, the hydrophobic bulky organic cations benefit to improve the environmental and operating stability owning to the better moisture tolerance and defects passivation ability. In this review, we will primarily introduce the quasi-2D lead halide perovskite materials from the structure to their optical and electrical properties. Then, we will focus on the advances of optical pumping lasers based on quasi-2D lead halide perovskite materials as gain mediums. Especially, more attention will be paid to perovskite lasers using distributed feedback (DFB) and distributed Bragg reflector (DBR) cavities. Furthermore, the key issues to realize quasi-2D perovskite-based electrical pumping lasers will be discussed.
We report one-pot synthesis of Fe(III)–polydopamine (PDA) complex nanospheres, their structures, morphology evolution, and underlying mechanism. The complex nanospheres were synthesized by ...introducing ferric ions into the reaction mixture used for polymerization of dopamine. It is verified that both the oxidative polymerization of dopamine and Fe(III)–PDA complexation contribute to the “polymerization” process, in which the ferric ions form coordination bonds with both oxygen and nitrogen, as indicated by X-ray absorption fine-structure spectroscopy. In the “polymerization” process, the morphology of the complex nanostructures is gradually transformed from sheetlike to spherical at the feed Fe(III)/dopamine molar ratio of 1/3. The final size of the complex spheres is much smaller than its neat PDA counterpart. At higher feed Fe(III)/dopamine molar ratios, the final morphology of the “polymerization” products is sheetlike. The results suggest that the formation of spherical morphology is likely to be driven by covalent polymerization-induced decrease of hydrophilic functional groups, which causes reself-assembly of the PDA oligomers to reduce surface area. We also demonstrate that this one-pot synthesis route for hybrid nanospheres enables the facile construction of carbonized PDA (C-PDA) nanospheres uniformly embedded with Fe3O4 nanoparticles of only 3–5 nm in size. The C-PDA/Fe3O4 nanospheres exhibit catalytic activity toward oxygen reduction reaction and deliver a stable discharge voltage for over 200 h when utilized as the cathode in a primary Zn–air battery and are also good recyclable catalyst supports.
Fumarase catalyzes the interconversion of fumarate and L-malate in the tricarboxylic acid cycle. The Dahl salt-sensitive (SS) rat, a model of salt-sensitive hypertension, exhibits fumarase ...insufficiencies. To investigate the mechanism mediating the effect of fumarase-related metabolites on hypertension, we considered the pathway in which L-malate can be converted to oxaloacetate, aspartate, argininosuccinate, and L-arginine, the substrate of nitric oxide (NO) synthase. The levels of aspartate, citrulline, L-arginine, and NO were significantly decreased in the kidneys of SS rats compared to salt-insensitive consomic SS.13BN rats. Knockdown of fumarase in human kidney cells and vascular endothelial cells resulted in decreased levels of malate, aspartate, L-arginine, and NO. Supplementation of aspartate or malate increased renal levels of L-arginine and NO and attenuated hypertension in SS rats. These findings reveal a multi-step metabolic pathway important for hypertension in which malate and aspartate may modulate blood pressure by altering levels of L-arginine and NO.
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•The Dahl salt-sensitive (SS) rat exhibits fumarase insufficiencies•Aspartate, citrulline, L-arginine, and NO are decreased in the kidneys of SS rats•Knockdown of fumarase decreases malate, aspartate, L-arginine, and NO in cells•Aspartate or malate increases L-arginine and NO and attenuates hypertension
Hou et al. discovered a multi-step metabolic pathway involved in the regulation of blood pressure in a model of salt-sensitive hypertension. In this pathway, fumarase insufficiencies and lower levels of malate result in decreased levels of aspartate, leading to decreased L-arginine regeneration and NO production and contributing to hypertension.
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•An indoor artificial simulated wind-driven rain simulator was constructed.•Soil erosion and nitrogen loss are significantly influenced by wind-driven rain.•Effect of wind direction ...on soil and nitrogen loss may be positive or negative.•Changes of hydrological characteristics are the main reasons for the loss processes.
“Wind-driven rain” is the main form of natural rainfall. Wind affects runoff, soil, and nutrient loss processes on slopes by changing rainfall characteristics. Wind direction is one of the main factors affecting the falling trajectory of raindrops, raindrop splash angle, and direction of the rainfall erosivity force. However, existing research on soil displacement and nitrogen loss driven by different wind directions and rainfall is still lacking. Based on a simulated wind-driven rain experiment, this study explored the influence of different wind directions (leeward, windward, and crosswind) on runoff, sediment yield, and nitrogen loss on slopes. The results showed that wind direction had a significant influence on runoff, sediment yield, and nitrogen loss in both runoff and sediment. The influence of wind direction on the slope runoff and sediment yield rates was leeward > crosswind > windless > windward. Compared with windless rainfall, the average runoff rate and sediment yield rate under leeward rainfall and crosswind rainfall increased by 6.17%–11.56% and 37.75%–41.58%, and 1.80%–2.40% and 13.31%–18.12%, respectively, while under windward rainfall, they decreased by 5.13%–7.38% and 7.86%–13.02%, respectively. Hydrodynamic parameters are physical parameters that characterize the process of sand-bearing shallow flow acting on surface soil particles. The mean flow velocity and unit stream power affected by the wind direction were ranked: leeward > windless > crosswind > windward. The mean flow velocity and unit stream power under leeward conditions were both 1.31 times those under windless conditions, indicating that leeward wind strengthened the erosion effect of the slope flow on the soil. The mean flow velocity and unit stream power caused by different wind directions may be the main reasons for soil erosion processes. The average nitrogen loss rate in runoff was ranked: windward > crosswind > windless > leeward. The law of nitrogen loss rate in the sediment is consistent with the regularity of the sediment yield rate in all wind directions, which increased respectively by 60.18%–163.86% and 19.39%–69.57% under leeward and crosswind conditions, respectively, and decreased by 10.23%–25.15% under windward conditions when compared to windless treatment. Therefore, when the intensity of wind-driven rain is constant, the impact of wind direction on slope runoff, sediment yield, and nitrogen loss is uncertain and may be either positive or negative. The angle between the raindrop movement direction and the runoff flow direction on the slope changes owing to the influence of different wind directions. This leads to changes in the slope infiltration rate, hydrological characteristics, and soil crusting process, and is one of the main reasons for the difference in soil erosion and nutrient loss rates.
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