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Lithium plating in working batteries has attracted wide attention in the exploration of safe energy storage. Establishing an effective and rapid early-warning method is strongly considered but quite challenging since lithium plating behavior is determined by diverse factors. In this contribution, we present a non-destructive electrochemical detection method based on transient state analysis and three-electrode cell configuration. Through dividing the iR drop value by the current density, the as-obtained impedance quantity (Ri) can serve as a descriptor to describe the change of electrochemical reaction impedance on the graphite anode. The onset of lithium plating can be identified from the sharp drop of Ri. Once the dendritic plated lithium occurs, the extra electrochemical reactions at the lithium interfaces leads to growing active area and reduced surface resistance of the anode. We proposed a protocol to operate the batteries under the limited capacity, which renders the cell with 98.2% capacity retention after 1000 cycles without lithium plating. The early-warning method has also been validated in in-situ optical microscopy batteries and practical pouch cells, providing a general but effective method for online lithium plating detection towards safe batteries.

The red upconversion emission of Ho3+ ions, in the optical window of biological tissue, exhibits excellent prospects in biological applications. This study aims to enhance the red upconversion emission intensity of Ho3+ ions in NaLuF4:20%Yb3+/2%Ho3+/12%Ce3+ nanoparticles through building different core-shell structures with different excitation wavelengths. A significantly enhanced red upconversion emission with a higher red-to-green ratio was successfully obtained in NaLuF4:20%Yb3+/2%Ho3+/12%Ce3+@NaLuF4 core-shell nanoparticles by introducing the Yb3+ and Yb3+/Nd3+ ions into the NaLuF4 shell, with enhancement of the red emission occurring when Yb3+ and Nd3+ ions in the shell transfer more excitation energy to the Ho3+ ions. Investigation of the red emission enhancement mechanism is based on spectral characteristics and lifetimes. We examined the synergistic effect of dual-wavelength co-excitation NaLuF4:20%Yb3+/2%Ho3+/12% Ce3+@NaLuF4:10%Yb3+/15%Nd3+ core-shell nanoparticles to establish optimal excitation conditions. It is hoped that this method, using red upconversion emission core-shell nanoparticles with multi-mode excitation, can provide new ways to expand the applications of rare-earth luminescent materials in biomedicine and anti-counterfeiting.

Epilepsy detection and focus location are urgent issues that need to be solved in epilepsy research. A cortex conformable and fine spatial accuracy electrocorticogram (ECoG) sensor array, especially for real-time detection of multicortical functional regions and delineating epileptic focus remains a challenge. Here, we fabricated a polydimethylsiloxane (PDMS)-parylene hybrid, flexible micro-ECoG electrode array. The multiwalled carbon nanotubes (MWCNTs)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) nanocomposite-modified electrode interface significantly improved the sensing performance with low impedance (20.68 ± 6.65 kΩ), stable phase offset, and high sensitivity. The electrophysiological activities of multicortical brain regions (somatosensory cortex, parietal association cortex, and visual cortex) were simultaneously monitored during normal and epileptic statuses. The epileptic ECoG activities spread spatiotemporally from the starting point toward the adjacent cortex. Significant variations of the waveform, power, and frequency band were observed. The ECoG potential (123 ± 23 μV) at normal status was prominently up to 417 ± 87 μV at the spike wave stage. Besides, the power for epileptic activity (11.049 ± 4.513 μW) was 10 times higher than that (1.092 ± 0.369 μW) for normal activity. In addition, the theta frequency band was found to be a characteristic frequency band of epileptic signals. These joint analysis results of multicortical regions indicated that the active micron-scale region on the parietal association cortex was more likely to be the epileptogenic focus. Cortical mapping with high spatial detail provides the accurate delineation of lesions. The flexible micro-ECoG electrode array is a powerful tool for constructing a spatiotemporal map of the cortex. It provides a technical platform for epileptic focus location, biomedical diagnosis, and brain-computer interaction.

Timely and rapid detection of biomarkers is extremely important for the diagnosis and treatment of diseases. However, going to the hospital to test biomarkers is the most common way. People need to spend a lot of money and time on various tests for potential disease detection. To make the detection more convenient and affordable, we propose a paper-based aptasensor platform in this work. This device is based on a cellulose paper, on which a three-electrode system and microfluidic channels are fabricated. Meanwhile, novel nanomaterials consisting of amino redox graphene/thionine/streptavidin-modified gold nanoparticles/chitosan are synthesized and modified on the working electrode of the device. Through the biotin-streptavidin system, the aptamer whose 5'end is modified with biotin can be firmly immobilized on the electrode. The detection principle is that the current generated by the nanomaterials decreases proportionally to the concentration of targets owing to the combination of the biomarker and its aptamer. 17β-Estradiol (17β-E2), as one of the widely used diagnostic biomarkers of various clinical conditions, is adopted for verifying the performance of the platform. The experimental results demonstrated that this device enables the determination of 17β-E2 in a wide linear range of concentrations of 10 pg mL-1 to 100 ng mL-1 and the limit of detection is 10 pg mL-1 (S/N = 3). Moreover, it enables the detection of targets in clinical serum samples, demonstrating its potential to be a disposable and convenient integrated platform for detecting various biomarkers.

Lithium metal batteries are considered a promising candidate for high-energy-density energy storage. However, the strong reducibility and high reactivity of lithium lead to low Coulombic efficiency when contacting oxidants, such as lithium polysulfide caused by the serious "shuttle effect" in lithium-sulfur batteries. Herein we design selectively permeable lithium-ion channels on lithium metal surface, which allow lithium ions to pass through by electrochemical overpotential, while the polysulfides are effectively blocked due to the much larger steric hindrance than lithium ions. The selective permeation of lithium ions through the channels is further elucidated by the molecular simulation and visualization experiment. Consequently, a prolonged cycle life of 75 cycles and high Coulombic efficiency of 99 % are achieved in a practical Li-S pouch cell with limited amounts of lithium and electrolyte, confirming the unique role the selective ion permeation plays in protecting highly reactive alkali metal anodes in working batteries.

Welding properties of three alloys with different Cu contents (0.1, 0.4 and 0.9 wt.%) is studied by means of melt inert-gas welding (MIG). The results showed that, with the increase of Cu content from 0.1 wt.% to 0.9 wt.%, the strength and elongation increased obviously. When the Cu content was 0.9 wt.%, the strength and elongation reached 375MPa and 15%, respectively, which is a better match for bearing structure part of vehicles application. Besides, the adding of Cu element provided an increase limit for welding joint strength. Due to abundant coarse phases in fusion zone (FZ) and welding zone (WZ), the strength slightly increased and the failure fracture was different compared with that of 0.1Cu and 0.4Cu alloy. Present result was meaningful and valuable for pushing aluminum application automobile structural parts and other engineering components.

Clarifying interfacial electronic effects on molecular adsorption is of great significance in many chemical and biochemical processes but remains a challenge. Here, we have successfully used STM breaking junction and shell-isolated nanoparticle-enhanced Raman spectroscopy technique to probe electron transport and adsorption geometries of pyridyl molecules at Au(111). Modifying Au(111) surface with 1-butyl-3-methylimidazolium cation-containing ionic liquids (ILs) decreases surface electron density and stabilizes a vertical orientation of pyridine through nitrogen atom σ-bond interactions, resulting in uniform adsorption configurations for forming molecular junctions. Furthermore, fine modulation from vertical, tilted, to flat, is achieved on adding water to ILs, leading to a new peak around 1633 cm -1 ascribed to CC stretching mode of adsorbed pyridyl ring and 316% modulation of single-molecule conductance. Combining with DFT calculation reveals that the dihedral angle between adsorbed pyridyl ring and surface decreases with increasing surface electronic density, which enhances electron-donation from surface to pyridyl ring.

Additive manufacturing of ceramics gains increasing attention in recent years, as ceramic material like clay processes distinctive merits, including hardness, thermal and chemical stability, etc. The customer-level extrusion-based ceramics 3D printer is getting easily achievable. However, due to its semi-liquid and highly viscoelastic properties, the clay material causes new challenges to the computational aspects. It does not dry instantly and may collapse during the accumulated force from new layers breaks the moment equilibrium, especially when adjacent layers have less overlap region. We tackle this unique problem, focusing on shell-like models in extrusion-based ceramics printing in this paper. We propose a structural analysis algorithm that considers the moment equilibrium for each layer along the fabrication process. We also present a computational framework to enhance the structural stability by local thickening of the shell models without affecting the appearance. We demonstrate the printing process and physical results to validate our method.

Traditional luminescent liquid crystals (LLCs) suffer from fluorescence quenching caused by aggregation, which greatly limits their further application. In this work, a kind of novel LLCs (named carbonized polymer dot liquid crystals (CPD-LCs)) are designed and successfully synthesized through grafting the rod-shaped liquid crystal (LC) molecules of 4'-cyano-4-(4″-bromohexyloxy) biphenyl on the surface of CPDs. The peripheral LC molecules not only increase the distance between different CPDs to prevent them from aggregating and reduce intermolecular energy resonance transfer but also make this LLC have an ordered arrangement. Thus, the obtained CPD-LCs show good LC property and excellent high luminous efficiency with an absolute photoluminescence quantum yield of 14.52% in the aggregated state. Furthermore, this kind of CPD-LC is used to fabricate linearly polarized devices. The resultant linearly polarized dichroic ratio (N) and polarization ratio (ρ) are 2.59 and 0.44, respectively. Clearly, this type of CPD-LC shows promising applications for optical devices.

Uncontrolled Li plating in graphite electrodes endangers battery life and safety, driving tremendous efforts aiming to eliminate Li plating. Herein we systematically investigate the boundary of Li plating in graphite electrode for safe lithium-ion batteries. The cell exhibits superior safety performance than that with Li dendrites by defining the endurable amount of uniform Li plating in graphite anode. The presence of "dead Li" can be eliminated owing to the uniform distribution of Li plating, and the average Coulombic efficiency for deposited Li during reversible plating/stripping process is decoupled as high as about 99.5 %. Attributing to the limited Li plating with superior Coulombic efficiency, the LiNi0.5 Mn0.3 Co0.2 O2 | graphite cell achieves a high capacity retention of 80.2 % over 500 cycles. This work sheds a different light on further improving the fast-charging capability, low-temperature performance, and energy density of practical lithium-ion batteries.

The article established a modelling that predicted and measured the quenching and pre-stretching stress in 7050 aluminum alloy thick plate in order to make the alloy suitable enough for manufacturing in the aerospace industries. The results show that both the rolling direction component stress and the transverse direction component stress have a “M” distribution along the plate thickness of 7050 aluminum alloy thick plate, but the level is slightly different, but the level is slightly different. The maximum value of quenching residual stress is about 187MPa in the 80mm thick of 7050 plate. Pre-stretching of the heat treated and quenched alloy to 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0% and 3.5% to reduce the residual stresses. It has been recorded that more than 90% reduction of residual stresses were observed in a pre-stretching rage of 2-3%. Measuring the surface residual stresses of the alloy by ultrasonic methods and measuring the internal residual stresses of the alloy by crack compliance methods. The two methods are used to verify the model. The difference between the measurement and the simulation is within 40MPa. The experimental data of the ultrasonic and the crack compliance methods were found to correspond well with the simulated models. This shows that the simulation model can effectively predict the evolution of residual stress in 7050 aluminum alloy thick plate, and the simulation model can also be reconstructed and inspected through the experimentally measurement.

Solid electrolyte interphase (SEI) has been widely employed to describe the new phase formed between anode and electrolyte in working batteries. Significant advances have been achieved on the structure and composition of SEI as well as on the possible ion transport mechanism. However, the nucleation and growth mechanism of SEI catches little attention, which requires the establishment of isothermal electrochemical crystallization theory. Herein we explore the virgin territory of electrochemically crystallized SEI. By using potentiostatic method to regulate the decomposition of anions, an anion-derived SEI forms on graphite surface at atomic scale. After fitting the cur-rent-time transients with Laviron theory and Avrami formula, we conclude that the formation of anion-derived interface is surface reaction controlled and obeys the two-dimensional (2D) progressive nucleation and growth model. Atomic force microscope (AFM) images emphasize the conclusion, which reveals the mystery of isothermal electrochemical crystallization of SEI.

Lithium-ion batteries with routine carbonate electrolytes cannot exhibit satisfactory fast-charging performance and lithium plating is widely observed at low temperatures. Herein we demonstrate that a localized high-concentration electrolyte consisting of 1.5 M lithium bis(fluorosulfonyl)imide in dimethoxyethane with bis(2,2,2-trifluoroethyl) ether as the diluent, enables fast-charging of working batteries. A uniform and robust solid electrolyte interphase (SEI) can be achieved on graphite surface through the preferential decomposition of anions. The established SEI can significantly inhibit ether solvent co-intercalation into graphite and achieve highly reversible Li+ intercalation/de-intercalation. The graphite | Li cells exhibit fast-charging potential (340 mAh g-1 at 0.2 C and 220 mAh g-1 at 4 C), excellent cycling stability (ca. 85.5 % initial capacity retention for 200 cycles at 4 C), and impressive low-temperature performance.

Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase (SEI) covered on the graphite anode determines the service life of a battery. The formation method and the formation temperature at initial cycle of a battery determine the feature of the SEI. Herein, we investigate the gap of formation behavior in both a half cell (graphite matches with lithium anode) and a full cell (graphite matches with NCM, short for LiNixCoyMn1−x−yO2) at different temperatures. We conclude that high temperature causes severe side reactions and low temperature will result in low ionic conductive SEI layer, the interface formed at room temperature owns the best ionic conductivity and stability.

Using an Y(NO3)3 solution as a liquid medium, an Fe2O3-doped 8YSZ (8 mol% yttria-stabilized zirconia) electrolyte can be fabricated by a cold sintering process (CSP) and a conventional sintering (CS) at 1100 °C, and a relative density of more than 95% can be achieved. The phase structure, sintering behaviour and electrical properties of the 8YSZ samples were investigated in this study. The results indicate that the sinterability of the 8YSZ electrolyte can be enhanced by the CSP. Moreover, the formation of the monoclinic phase originating from the Fe2O3 dopant was greatly suppressed by introducing the Y(NO3)3 solution into the CSP, which greatly improved the electrical properties (i.e. the ionic conductivity) of the 8YSZ electrolyte. The sintered Fe2O3-doped 8YSZ provides support for the fabrication of high-performance solid oxide fuel cells (SOFCs) in a convenient and energy-saving way.

Lithium metal is recognized as one of the most promising anode materials owing to its ultrahigh theoretical specific capacity and low electrochemical potential. Nonetheless, dendritic Li growth has dramatically hindered the practical applications of Li metal anodes. Realizing spherical Li deposition is an effective approach to avoid Li dendrite growth, but the mechanism of spherical deposition is unknown. Herein, a diffusion-reaction competition mechanism is proposed to reveal the rationale of different Li deposition morphologies. By controlling the rate-determining step (diffusion or reaction) of Li deposition, various Li deposition scenarios are realized, in which the diffusion-controlled process tends to lead to dendritic Li deposition while the reaction-controlled process leads to spherical Li deposition. This study sheds fresh light on the dendrite-free Li metal anode and guides to achieve safe batteries to benefit future wireless and fossil-fuel-free world.

In this article, a simplified iron/spinel catalyst system was adopted as the Fischer–Tropsch to light olefins (FTO) catalyst to rule out disturbances from efficient promoters (e.g., K or combination of S/Na). Supported by regular supports (e.g., Al2O3, carbon, etc.), unpromoted iron catalysts commonly have a maximum C2=–C4= hydrocarbon distribution below 28%. Supported by a composite oxide support (i.e., nominal composition, ZnAl4O7, calcined at 350 °C), our porous, unpromoted iron catalyst exhibits a maximum C2=–C4= hydrocarbon distribution of 40%, achieving a significant increase by ca. 42% in comparison with regular supports. Appropriate lifting of atomic Zn/Fe ratio, as well as, reducing at lower temperature plus mild carburization, both can make a supported iron catalyst more efficient in hindering C–C coupling and producing light olefins. The structure of ZnAl4O7 support remains stable in iron catalysts during CO hydrogenation.

Lithium‐sulfur (Li‐S) batteries are one of the most promising candidates for high energy density rechargeable batteries beyond current Li‐ion batteries. However, severe corrosion of Li metal anode and low Coulombic efficiency (CE) induced by the unremitting shuttle of Li polysulfides immensely hinder the practical applications of Li‐S batteries. Herein, a compact inorganic layer (CIL) formed by ex situ reactions between Li anode and ionic liquid emerged as an effective strategy to block Li polysulfides and suppress shuttle effect. A CE of 96.7% was achieved in Li‐S batteries with CIL protected Li anode in contrast to 82.4% for bare Li anode while no lithium nitrate was employed. Furthermore, the corrosion of Li during cycling was effectively inhibited. While applied to working batteries, 80.6% of the initial capacity after 100 cycles was retained in Li‐S batteries with CIL‐protected ultrathin (33 μm) Li anode compared with 58.5% for bare Li anode, further demonstrating the potential of this strategy for practical applications. This study presents a feasible interfacial regulation strategy to protect Li anode with the presence of Li polysulfides and opens avenues for Li anode protection in Li‐S batteries under practical conditions.

Owing to its critical role in the development of female reproductive tissues and as a clinical biomarker, there is an urgent need to develop a rapid and cost-effective method to sensitively detect 17β-estradiol (E2). In this work, a folding aptasensor platform with microfluidic channels for the label-free electrochemical detection of E2 is described. The platform, designed with a delicate folding structure, integrating filter holes, microfluidic channels, reaction chambers, and a three-electrode system, is extremely easy to use. To increase the detection sensitivity and immobilize the aptamer, we synthesized a novel nanoassembly consisting of amine-functionalized single-walled carbon nanotube/new methylene blue/gold nanoparticles (AuNPs) and modified the working electrode with this nanoassembly. The calibration curve obtained from the experimental results exhibited a linear range between 10 pg mL-1 and 500 ng mL-1 (R2 = 0.993), and a detection limit of 5 pg mL-1 was achieved (S/N = 3). Furthermore, experiments to detect E2 in clinical serum were conducted, and the results were highly similar to those obtained using a large electrochemical luminescence apparatus. By integrating multiple functional components, adopting novel nanoassemblies, and using a folding structure, this paper-based platform not only has great potential as a simple and convenient integrated device for point-of-care testing of E2, but also as a portable, low-cost, and highly sensitive aptasensor platform capable of detecting many diagnostic biomarkers with the appropriate aptamers.

Outstanding wide-bandgap semiconductor materials like gallium nitride (GaN) have been extensively utilized in power electronics, radiofrequency power amplifiers, and harsh environment adaptability. Due to its quantum confinement impact in enabling desired deep-ultraviolet emission, excitonic impact, and electronic transport features, two-dimensional (2D) GaN has been one of the most remarkable areas for the future growth of microelectronic devices. Here, for the first time, we report a large area, wide bandgap, and room-temperature 2D GaN synthesis and printing strategy via liquid metal gallium surface-confined nitridation reaction. The developed low-temperature synthesis and printing process is consistent with various electronic device manufacturing methods and thus opens a way for the cost-effective growth of the third-generation semiconductor. In particular, the fully printed field-effect transistors relying on the GaN show p-type switching with an on/off ratio greater than 105, maximum field-effect hole mobility of 53 cm2 V−1 s−1, and a small sub-threshold swing at room temperature. The current study establishes a room temperature way to produce the GaN, which can be further verified, generalized, and realized for various upcoming electronic and photoelectronic applications.

Cylindrical shells are principal structural elements that are used for many purposes, such as offshore, sub-marine, and airborne structures. The nonlinear mechanics model of internal blast loading was established to predict the dynamic blast pressure of cylindrical shells. However, due to the complexity of the nonlinear mechanical model, the solution process is time-consuming. In this study, the nonlinear mechanics model of internal blast loading is linearized, and the dynamic blast pressure of cylindrical shells is solved. First, a mechanical model of cylindrical shells subjected to internal blast loading is proposed. To simplify the calculation, the internal blast loading is reduced to linearly uniform variations. Second, according to the stress function method, the dynamic blast pressure equation of cylindrical shells subjected to blast loading is derived. Third, the calculated results are compared with those of the finite element method (FEM) under different durations of dynamic pressure pulse. Finally, to reduce the errors, the dynamic blast pressure equation is further optimized. The results demonstrate that the optimized equation is in good agreement with the FEM, and is feasible to linearize the internal blast loading of cylindrical shells.

High-energy-density lithium (Li) metal batteries are severely hindered by the dendritic Li deposition dictated by non-uniform solid electrolyte interphase (SEI). Despite its unique advantages in improving the uniformity of Li deposition, the current anion-derived SEI is unsatisfactory under practical conditions. Herein regulating the electrolyte structure of anions by anion receptors was proposed to construct stable anion-derived SEI. Tris(pentafluorophenyl)borane (TPFPB) anion acceptors with electron-deficient boron atoms interact with bis(fluorosulfonyl)imide anions (FSI- ) and decrease the reduction stability of FSI- . Furthermore, the type of aggregate cluster of FSI- in electrolyte changes, FSI- interacting with more Li ions in the presence of TPFPB. Therefore, the decomposition of FSI- to form Li2 S is promoted, improving the stability of anion-derived SEI. In working Li | LiNi0.5 Co0.2 Mn0.3 O2 batteries under practical conditions, the anion-derived SEI with TPFPB undergoes 194 cycles compared with 98 cycles of routine anion-derived SEI. This work inspires a fresh ground to construct stable anion-derived SEI by manipulating the electrolyte structure of anions.

Cylinder noise can be remarkably reduced when the surface is helically wrapped with cables along the cylinder span. In this paper, aeroacoustic and aerodynamic experiments are conducted to reveal the noise reduction mechanism of the helical-cable technique. With the application of helical cables on the single circular cylinder, three-dimensional flow is promoted into the cylinder near wake, leading to the suppression of two-dimensional vortex shedding process and flow fluctuations. Besides, the three-dimensional wake also destroys the in-phase relationship of flow fluctuations along the cylinder span, leading to the reduction of spanwise correlation length and noise radiation efficiency. These two effects together contribute to the cylinder noise reduction. Furthermore, this helical-cable technique is extended to tandem cylinders and the results show that it can also reduce the tandem cylinder noise effectively. Especially for the moderate and large spacing tandem cylinder configurations, the key of the noise reduction is the control on the upstream cylinder.

In hydrogen fuel cells, the sluggish oxygen reduction reaction (ORR) requires the catalysts used. Unfortunately, the precious platinum based catalysts still exhibit the best ORR activity in the commercial hydrogen fuel cells. Therefore, developing non-precious metal catalysts ORR become an important aspect for the utilization of hydrogen energy by using hydrogen fuel cells to develop non-precious catalysts and understand their active sites of ORR, herein the cobalt and nitrogen co-doped CNTs, nitrogen-doped CNTs and cobalt doped CNTs were prepared, respectively, and their catalytic properties toward ORR were tested and compared. The surface composition, microstructure and ORR performance of the samples were examined by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), pore/specific surface analyzer and electrochemical methods. The results demonstrate that as the catalyst, the cobalt and nitrogen co-doped CNTs owns the highest ORR limiting current density, the most positive ORR onset potential and the largest transfer electron number close to four, and thus exhibits the better ORR catalytic performance compared to the other two samples of the nitrogen-doped CNTs and the cobalt doped CNTs. The good ORR performance of cobalt and nitrogen co-doped CNTs can be attributed to its active sites of nitrogen containing functional groups, cobalt or cobalt oxides, Co-Nx structure, and the synergistic effect of these sites on ORR.

The desulfurization performance of magnesium slag has been improved by the modified method of quenching hydration, but it still cannot meet the industrial requirements. Based on the research of additives for calcium-based desulfurizer, NaCl, CaCl2, Na2SO4, CaSO4, Na2CO3, K2CO3, acetic acid and adipic acid are used for modification of quenching hydrated magnesium slag. TGA are used for analysis of magnesium slag desulfurization performance; XRD, SEM, EDS and BET are used for analysis of modified magnesium slag composition, surface morphology and microscopic characteristics, respectively, obtaining the modification mechanism of different additives on the quenching hydrated magnesium slag. The results showed that: the best desulfurizer was 2% Na2SO4 modified magnesium slag, and the calcium conversion rate reached 40.16%. Cl− and SO42− mainly improve the desulfurization performance of magnesium slag by improving the specific surface area and pore volume of magnesium slag, and the modification effect of SO42− was better than Cl−. CO32− mainly through the reaction with Ca(OH)2 to produce CaCO3 that could crystalize on the surface of magnesium slag, thus improving the desulfurization performance of magnesium slag. Organic acids enhanced the transmission of H+ in hydrated slurry and promoted the dissolution of Ca2SiO4.

A friction torque model of ball bearings with geometrical imperfections is proposed, integrating developed models of friction, raceway waviness, and multi-body dynamics. Torque variations consisting of average and fluctuation values for angular contact ball bearings due to waviness including linear, nonlinear and multi-orders situation are analyzed in time and frequency domains. The influences of waviness amplitude, load and speed are evaluated. Additionally, the correlation between axial displacement and torque fluctuation of ball bearings is discussed, and their spectrum similarity under pure axial load and the relative low-frequency amplitude enhancement of the torque spectrum under combined load are observed. Finally, a torque experiment is carried out on a bearing test apparatus, and the effectiveness of the present model is verified.

Surface wear is an inevitable damage of wire ropes used in winding hoist. It always reduces the service life of the wire rope and threatens the mine safety. The characteristics of the surface wear scar caused by sliding contact between ropes were discussed in a quantitative and qualitative method for this paper. A series of breaking tensile tests were carried out to investigate the effects of the wear characteristic parameters on the bearing capacity of the rope. Furthermore, the fracture failure behaviors of the rope with different wear scars were analyzed. Results show that the wear scar changes from distributing on one strand to evenly distributed on two adjacent strands as the sliding wear position changes from the strand peak to valley. When the wear region concentrates on one strand, the maximum wear depth increases from approximately 0.46 mm to approximately 0.64 mm with the increase of wear area. Broken wires seriously affect the elongation and breaking force of the rope. The maximum breaking force is approximately 42 KN and the maximum local elongation is approximately 1.5 mm under the condition of broken wires. Additionally, the external wires of the strand are easier to fracture caused by torsion and tension together. Furthermore, the shear lip and the fibre region on the fracture surface of the wires become not very obvious with the increase of the wear scar parameters.

With the thickness less than 5 nm, super-thin LiV3O8 nanosheets have already been successfully synthesized by transformation from super-thin V2O5·xH2O nanosheets, moreover, super-thin LiV3O8 nanosheets@graphene (LVO/G) sandwich-like layer-by-layer nanostructures were successfully obtained via a facile self-assembly method and annealing treatment. Such interesting LVO/G nanostructures as cathodes for lithium ion batteries not only show high capacity up to 397.2 mA h g−1 and outstanding rate capabilities (171 mA h g−1 at 10 C, 112 mA h g−1 at 15 C), but also present super-long cycle performance (301.2 mA h g−1 after 500 cycles at 1 C). As far as we known, the LVO/G cathodes exhibit ultrahigh lithium storage performances even much higher than those of previously reported literatures of LiV3O8, which demonstrates that such sandwich-like layer-by-layer LVO/G nanostructures is a potential candidate cathode material for the next generation of batteries.

Lithium (Li) metal anodes hold great promise for next-generation high-energy-density batteries, while the insufficient fundamental understanding of the complex solid electrolyte interphase (SEI) is the major obstacle for the full demonstration of their potential in working batteries. The characteristics of SEI highly depend on the inner solvation structure of lithium ions (Li+ ). Herein, we clarify the critical significance of cosolvent properties on both Li+ solvation structure and the SEI formation on working Li metal anodes. Non-solvating and low-dielectricity (NL) cosolvents intrinsically enhance the interaction between anion and Li+ by affording a low dielectric environment. The abundant positively charged anion-cation aggregates generated as the introduction of NL cosolvents are preferentially brought to the negatively charged Li anode surface, inducing an anion-derived inorganic-rich SEI. A solvent diagram is further built to illustrate that a solvent with both proper relative binding energy toward Li+ and dielectric constant is suitable as NL cosolvent.

Membrane-based separation has served as an environmentally friendly technology over many conventional separation technologies in production of clean water, energy, and other materials. However, the vast amount of organic solvents used in membrane fabrication violates its initial intention. Therefore, to meet the needs of green chemistry and sustainable development, the traditional organic solvents must be replaced by environmentally benign solvents to reduce the solvent pollution. Ionic liquids have grabbed increasing interest as a kind of green solvents due to their low vapor pressure, chemical and thermal stability, recyclability, and diversity of ion combination. They have showed great superiority as the solvents for membrane fabrication. Contrary to traditional molecular solvents, the special properties of ionic liquids bring about distinct phenomena during hollow fiber fabrication and unique properties of the membranes. Therefore this chapter discusses the fundamental science of using ionic liquids as the solvents for hollow fiber spinning. The properties of hollow fibers spun from ionic liquids are summarized first, followed by the examination of interactions between polymers and ionic liquids as well as their influences on solution rheology and phase inversion behavior. Afterwards, the effects of spinning parameters on hollow fiber performance are also illustrated. With the further industrialization of ionic liquids and the development of novel recovery technologies, ionic liquids may serve as effective and feasible solvents in the near future for the fabrication of hollow fiber membranes and the realization of green fabrication in the membrane industry.

Polyethersulfone (PES) mixed-matrix membranes (MMMs) incorporating a co-nanofiller of ZIF-8 and poly(ionic liquid) were constructed via a facile one-pot microemulsion strategy, aiming to increase the flux and anti-fouling properties of the original PES membranes. First, ZIF-8 nanoparticles were synthetized in the reverse microemulsion using 1-butyl-3-methylimidazolium (BmimOTF) ionic liquid as a surfactant and 1-vinyl-3-ethylimidazolium tetrafluoroborate (VeimBF4) polymerizable ionic liquid as an oil phase. Subsequently, the oil phase VeimBF4 in the reverse microemulsion was polymerized, and a latex containing ZIF-8 nanoparticles and poly(VeimBF4) was formed. Finally, MMMs were constructed by blending the latex with PES via the phase-inversion method. The microstructures of ZIF-8 and the MMMs were characterized by TEM, SEM, FTIR, XRD, and XPS analysis. Results showed that the mean size of ZIF-8 are small (10∼35 nm). Addition of the poly(VeimBF4) and ZIF-8 nanoparticles increased the pore size and hydrophilicity of MMMs. The maximum water flux was 105 L m−2·h−1·bar−1 and 90% flux recovery were obtained after five cycles of filtration, and little decrease of WCA appeared on all MMMs after the repeated experiment, indicated the good stability of MMMs. Compared with PES ultrafiltration membrane, pure water flux and flux recovery rate of the MMMs increased by 15 and 2.8 times respectively.

ZnGa2O4 is an important cathodoluminescent material which exhibits good near-infrared long afterglow characteristics after being Cr-doped into Ga sites (ZGO: Cr). The band structure, crystal structure and optical properties of ZGO: Cr are investigated by using first-principles calculations based on density functional theory. It is found that, in the ZGO: Cr system, due to the presence of the Cr-O bond, the distortion of the local lattice goes up as the Cr3+ doping amount increases. Meanwhile, impurity levels appear near the Fermi level of the ZGO system, and the orbital controlling the conduction band bottom gradually moves from the Ga-4s orbital to the Cr-3d orbital. Consequently, the real optical band-gap of the ZGO: Cr system becomes narrower, and the absorption edge undergoes a red-shift. The density of states of all upward and downward atomic spins is distributed asymmetrically, indicating that ZGO: Cr exhibits a certain amount of spin polarization. Additionally, the static dielectric constant of the ZGO: Cr material system increases with the increase in the Cr3+ doping amount. According to the findings, adjustments can be made of the doping concentration and energy range in the optical applications of ZGO: Cr material system.

Thin film nanocomposite membranes have become a feasible technology for heavy metal wastewater treatment. However, how to enhance the dispersibility and compatibility of nanomaterials in the selective layer is an important issue to improve the membrane performance of heavy metal removal. In this study, silica-poly(ionic liquid) nanoparticles were incorporated in the selective layer of TFN membranes. 1-Allyl-3-methyl imidazolium hexafluorophosphate ([AMIm]PF6) was selected to modify silica (SiO2) particles. The formed poly([AMIm]+) brushes provided charge properties to enhance dispersibility and organic part to improve compatibility in the polyamide layer of NF membranes. The resultant TFN membranes incorporated with SiO2-[AMIm]PF6 particles exhibited an increment of 34% water permeation and 41.6% MgCl2 rejection. Moreover, with an average rejection improvement of around 15% for heavy metal ions at pH = 5–6, the SiO2-[AMIm]PF6/PA membrane showed its superiority beyond the PA membrane. The electropositivity and microporous structure of the SiO2-[AMIm]PF6 particles enhanced their dispersibility and compatibility in the polyamide layer. Meanwhile, the proper pore size and structure of the SiO2-[AMIm]PF6 particles contributed to the channels for water transport and the sieving effect for most heavy metal ions. This work may facilitate the applications of TFN membranes in heavy metal wastewater treatment to alleviate the “trade-off” phenomenon.

Aminosilane materials, with their low cost and ease of modification, have exhibited great potential for the adsorption of perfluorinated compounds (PFCs) from water. However, this kind of material may be facing two drawbacks during its application: low resistance to hydrolysis and difficulties in separation from the water matrix. This work proposed a strategy of grafting N-(2-aminoethyl) aminopropyltrimethoxysilane (AE-APTMS) on the surface of magnetic γ-Fe2O3 nanoparticles by full utilization of the sorption sites provided by the aminosilane and the magnetism by γ-Fe2O3. The FTIR and XRD results verified the formation of the magnetic AE-APTMS nanocomposite. The core-shell nanocomposite showed a superparamagnetic property and an isoelectric point at pH = 8.2. Particularly, compared to the aminopropyltriethoxysilane (APTES) nanocomposite, the AE-APTMS nanocomposite exhibited improved hydrolytic stability with 60% less loss of the amine groups during the 48 h adsorption process, as the longer alkyl chain hindered the aminosilane detachment. The AE-APTMS nanocomposite exhibited a rapid adsorption with the removal efficiency of 78% for perfluorooctane sulfonate (PFOS) and 65% for perfluorooctanoate (PFOA) due to the electrostatic interaction and hydrophobic interaction. The regeneration and reuse of the magnetic AE-APTMS nanocomposite were conveniently realized with the removal efficiency higher than 70% for both PFOS and PFOA even after 15 adsorption-desorption cycles. The stable magnetic aminosilane nanocomposite with the ease of separation may provide a new strategy to achieve the economical and effective removal of typical PFCs from water.

A series of quenching hydration experiments of magnesium slag were carried out under different conditions (quenching and hydration temperatures, hydration time, liquid/solid ratio, and continuous/non-continuous process). During the hydration process, the electrical conductivity, pH, and hydration degree were obtained to characterize the reaction. Combined with the hydration degree, kinetic models were used to analyze the hydration kinetics and obtain the relevant parameters. To further understand the desulfurization performance of the hydrated magnesium slag, and the relationship between hydration and desulfurization, desulfurization experiments were carried out in a thermal gravimetric analyzer. Further, changes in the material composition and morphology after hydration were investigated by X-ray diffraction and scanning electron microscopy, respectively. The results showed that the non-continuous hydration could be described by a modified Krstulovic-Dabic model. The highest hydration degree (0.16) was achieved at the quenching temperature of 950 °C and hydration temperature of 80 °C. Orthogonal tests established the optimum conditions for continuous hydration: quenching temperature of 950 °C, liquid/solid ratio of 8, and hydration time of 8 h. In decreasing order, these three factors are ranked as hydration time > quenching temperature > liquid/solid ratio. The desulfurization performance of samples treated with continuous hydration was better than that treated with non-continuous hydration, with the calcium conversion rates of 30.3% and 13.3%, respectively.

This work presents a novel milling strategy for complex pocket machining by integrating radius-varying trochoidal (RVTR) toolpath with contour parallel (CP) toolpath. Based on a quantitative analysis on the fluctuation of material removal rates (MRR), the proposed strategy is able to precisely identify critical regions from complex pocket geometries, and then by integrating flexible trochoidal radius with adaptive trochoidal step, the proposed approach is able to integrate the RVTR toolpath into CP toolpath under a consistent transition of material removal rate. Moreover, by applying RVTR toolpath, the cutting force can be maintained constantly when machining critical regions. Comparing with the trochoidal milling function available with current mainstream CAM software, experimental investigation has shown that the proposed RVTR-CP toolpath integration strategy offers a better machining condition with minimized fluctuation of cutting forces. Moreover, the total length of toolpath is decreased considerably and hence the machining efficiency is greatly improved.

Modified magnesium slag could be used as a kind of practical desulfurizer. Four modification methods were studied in this paper, which were magnesium slag hydration, magnesium slag/fly ash hydration, magnesium slag quenching hydration and magnesium slag/additives hydration. The desulfurization performance of modified magnesium slag was characterized by its calcium conversion rate. The desulfurization experiments were carried out in Thermal Gravimetric Analyzer. Based on hydration kinetics and fractal theory, the relationship between desulfurization performance and hydration degree or fractal characteristics were, respectively, analyzed. The results showed that the optimal temperature of desulfurization reaction was 920 °C. When the mass ration of fly ash and calcium silicate of magnesium slag (MR) was 20, hydration time (tH) was 8 h, hydration temperature (TH) was 90 °C, the desulfurization performance was the best. The most efficient additive in hydration reaction was H2C2O4, the calcium conversion rate reached to 73.7% by adding 0.5% H2C2O4. The optimal hydration conditions for quenching magnesium slag/fly ash were also MR = 20, tH = 8 h, and the relationship between fractal dimension and calcium conversion rate was similar to parabolic. The activation energy of this hydration reaction was 72.37 kJ mol− 1. The relationship between hydration degree and calcium conversion rate was a positive correlation in the condition.

Biomass chars (bio-chars) prepared under two pyrolysis modes and with four particle size ranges were investigated. The pyrolysis modes included isothermal pyrolysis and non-isothermal pyrolysis with three heating rates (5 °C/min, 10 °C/min, and 15 °C/min). The particle size ranges were 58-75 μm, 75-106 μm, 106-150 μm, and 150-270 μm. The pyrolysis characteristics, pore structures, surface morphologies, and functional groups of the bio-chars were characterized by TGA, specific surface area and porosity analyses, SEM, and FTIR. The mercury adsorption was further explored by the adsorption kinetics. The results established the optimum pyrolysis conditions for mercury adsorption: pyrolysis temperature of 600 °C, heating rate of 10 °C/min, and particle size of 58-75 μm. In addition, the mercury adsorption processes were affected by both physical adsorption and chemical adsorption. Furthermore, the rate constants of the pseudo-first-order and pseudo-second-order models gradually increased with decreasing particle size.

This study attempted to enhance the permeation and antifouling performance of polyvinylidene fluoride (PVDF) ultrafiltration membranes. Reverse microemulsion containing cobalt and iron (Co–Fe) bimetallic hydroxide nanoparticles was blended with the PVDF membranes to construct a novel PVDF hybrid membrane. The permeation performance, antifouling property, and long-term operational stability of the hybrid membranes were evaluated via ultrafiltration process of water flux and bovine serum albumin (BSA) rejection. Structural characterization showed that the protection endowed by reverse microemulsion made the hydroxide nanoparticles to distribute uniformly in the PVDF polymeric matrix. The introduction of well-distributed bimetallic hydroxide nanoparticles substantially improved the pore structures and hydrophilicity of the PVDF hybrid membranes, thereby enhancing their permeation performance and antifouling property. The optimal water flux of the PVDF hybrid membranes (MD-10) reached 328 L·m−2·h−1 and was 5.4-fold higher than that of neat PVDF. Moreover, the MD-10 membrane had a high a high BSA rejection rate (91.04%). After four cycles of successive fouling-cleaning processes, the water flux of the MD-10 membrane still exceeded 160 L·m−2·h−1 and was fourfold higher than that of neat PVDF. However, excessive amounts of the microemulsion could not be uniformly mixed with the PVDF membranes, thereby decreasing the permeation and antifouling performance of the PVDF hybrid membranes.

Electrically conductive membranes have been regarded as a new alternative to overcome the crucial drawbacks of membranes, including permeability-selectivity trade-off and fouling. It is still challenging to prepare conductive membranes with good mechanical strength, high conductivity and stable separation performance by reliable materials and methods. This work developed a facile method of simultaneous phase inversion to prepare electrically conductive polyethersulfone (PES) membranes with carboxylic multiwalled carbon nanotubes (MWCNT) and graphene (Gr). The resultant MWCNT/Gr/PES nanocomposite membranes are composed of the upper MWCNT/Gr layer with good conductivity and the base PES layer providing mechanical support. MWCNT as nanofillers effectively turns the insulting PES layers to be electrically conductive. With the dispersing and bridging functions of Gr, the MWCNT/Gr layer shows an enhanced electric conductivity of 0.10 S/cm. This MWCNT/Gr/PES membrane in an electro-filtration cell achieves excellent retention of Cu(II) ions up to 98 % and a high flux of 94.5 L m−2∙h−1∙bar−1 under a low driven-pressure of 0.1 MPa. The conductive membrane also shows improved anti-fouling capability during protein filtration, due mainly to the electrostatic repulsion and hydrogen evolution reaction on the electrode. This facile strategy has excellent potential in electro-assistant membrane filtration for fouling control and effective separation.

Reversible lithium (Li) plating/stripping is essential for building practical high-energy-density batteries based on Li metal chemistry, which unfortunately remains a severe challenge. In this contribution, it is demonstrated that through the rational regulation of strong Li+ -anion coordination structures in a highly compatible low-polarity solvent, 2-methyl tetrahydrofuran, the Li plating/stripping assisted by a nucleation modulation procedure delivers a remarkably high average Coulombic efficiency under rather demanding conditions (99.7% and 99.5% under 1.0 mA cm-2 , 3.0 mAh cm-2 and 3.0 mA cm-2 , 3.0 mAh cm-2 , respectively). The exceedingly reversible cycling obtained herein is fundamentally correlated with the flattened Li deposition and minimized solid electrolyte interphase (SEI) generation/reconstruction in the customized condition, which notably restrains the growth rates of both dead Li0 (0.0120 mAh per cycle) and SEI-Li+ (0.0191 mAh per cycle) during consecutive cycles. Benefiting from the efficient Li plating/stripping manner, the assembled anode-free Cu|LiFePO4 (2.7 mAh cm-2 ) coin and pouch cells exhibit impressive capacity retention of 43.8% and 41.6% after 150 cycles, respectively, albeit with no optimization on the test conditions. This work provides guidelines into the targeted interfacial design of high-efficiency working Li anodes, aiming to pave the way for the practical deployment of high-energy-density Li metal batteries.

Dielectric elastomer (DE) is capable of large deformation under electrical excitation. However, DE is susceptible to breakdown failure in this electromechanical actuation. Using an analogy of fracture mechanics, we establish an energetic model to estimate the breakdown voltage of DE in actuation. The non-linear characteristics, including material parameters, stretch ratios, and ambient temperature are involved to determine the critical condition of breakdown failure. The model is verified by experimental data of VHB membranes, and then extended to different DE materials. With respect to applications, two types of classic dielectric elastomer actuators (DEAs) are analyzed, and their breakdown voltages are evaluated. This study can provide a path for optimization of DE in electromechanical actuator and insulator applications.

Hollow metal ion-phenolic capsules (HMPCs) were synthesized through the combination of chelation with multiple hydrogen bonding that derive from the interaction of tannic acid (TA) and Pluronic F127. In this strategy, TA, a renewable and natural polyphenol, plays main role in the whole reaction process: a) create the “TA/F127 emulsion” driven by the multiple hydrogen bonding; b) construct the skeleton of HMPCs via the coordination with CuⅡ. Furthermore, we expanded this advanced concept into the fabrication of metal-doped hollow mesoporous carbon spheres (MHMCSs) elegantly and obtained Cu-Fe co-doped hollow mesoporous carbon spheres with 3.9 nm pore size and high specific surface area (365 m2/g). Compared to existing technology, the redundant treatments (e.g. hydrothermal treatment, sacrificial template removal and quite long reaction time) and toxic raw materials (e.g. formaldehyde, resorcinol) have been abandoned. Full green concept throughout the whole synthesis process presents an elegant paradigm for the preparation of HMPCs and MHMCSs.

Manganese oxides are metastable phases due to oxygen loss at high temperature. Conventional ceramic routes need high temperature and thus are unsuitable for making MnOx foams. A mild templating route at 300–400 °C was developed to construct metastable MnOx foams. Interwoven OMS-2 (cryptomelane) nanofibers with a length-diameter ratio of ca. 3000 over a template may create an OMS-2 foam at 400 °C with an atmosphere of 21% O2 content, a MnO/C foam at 400 °C with an atmosphere of 0% O2 content, OMS-2/Mn3O4 foams at 400 °C with an atmosphere of 1–5% O2 content, or Mn3O4/MnO2 foams at 300–350 °C in an atmosphere of 1% O2 content. Three foam materials are materials with ductility while others belong to brittle materials.

This paper presents a parametric study on the far-field noise control effect of a circular cylinder with helical cables wrapping along cylinder span, aiming at finding an optimal operation condition for this treatment. Experimental results reveal that the noise control efficiency of this treatment is highly dependent on the non-dimensional thread pitch and cable density. The noise control efficiency gradually increases with the non-dimensional thread pitch and cable density increasing when both values are smaller than critical values. Further increasing the values of the two parameters, the control efficiency cannot increase any more. By choosing the optimal parameters of helical cables, both tonal and broadband noise can be remarkably suppressed, and the overall sound pressure level can be reduced by as large as 17 dB.

Supercritical carbon dioxide (SC-CO 2 ) drilling technology has far-reaching application potential in unconventional oil and gas exploration and development. Since SC-CO 2 has relatively low density and viscosity, effective cuttings-carrying has become one of the key points of SC-CO 2 drilling technology. The critical annulus up-returning velocity of cuttings-carrying by SC-CO 2 in deviated well is analyzed by means of theoretical analysis and experimental test, and the feasibility of SC-CO 2 cuttings-carrying is verified. The research shows that when the well angle exceeds 13°, the particles are started in a rolling fashion. The critical annulus up-returning velocity increases with the increase of the size of cuttings, sinking degree, and temperature, and it has an opposite trend with the change of pressure. When the well angle is in the range of 50°–80°, the critical annulus up-returning velocity reaches its maximum, and cuttings are difficult to be carried. Similar results are obtained through experimental study and theoretical analysis. The study provides the theoretical support for the development of supercritical carbon dioxide drilling technology.