Zr-based metal-organic frameworks (MOFs) have been developed in recent years to treat heavy metals, e.g. hexavalent chromium Cr⁶⁺ pollution, which damages the surrounding ecosystem and threaten human health. This kind of MOF is stable and convenient to prepare, but has the disadvantage of low adsorption capacity, limiting its wide application. To this end, a novel formic acid and amino modified MOFs were prepared, referred to as Form-UiO-66-NH2. Due to the modification of formic acid, its specific surface area, pore size, and crystal size were effectively expanded, and the adsorption capacity of Cr⁶⁺ was significantly enhanced. Under optimal conditions, Form-UiO-66-NH2 exhibited an excellent adsorption capacity (338.98 mg/g), ∼10 times higher than that reported for unmodified Zr-based MOFs and most other adsorbents. An in-depth study on the photoelectronic properties and pH confirmed that the adsorption mechanism of Form-UiO-66-NH2 to Cr⁶⁺ was electrostatic adsorption. After modification, the improvement of Cr⁶⁺ adsorption capacity by Form-UiO-66-NH2 was attributed to the expansion of its specific surface area and the increase in its surface charge. The present study revealed an important finding that Form-UiO-66-NH2 elucidated selective adsorption to Cr⁶⁺ in mixed wastewater containing toxic heavy metal ions and common nonmetallic water quality factors. This research provided a new acid and amino functionalization perspective for improving the adsorption capacity of Zr-based MOF adsorbents while simultaneously demonstrating their pertinence to target contaminant adsorption.
Effective fault diagnosis is important to ensure the reliability, safety, and efficiency of industrial robots. This article proposes a simple yet effective data acquisition strategy based on transmission mechanism analysis, using only one attitude sensor mounted on an end effector or an output component to monitor the attitude of all transmission components. Unlike widely used vibration-monitoring signals, attitude signals can provide fault features reflecting spatial relationships. Using one attitude sensor facilitates the data collection, but weakens fault features and introduces strong background noise in attitude signals. To learn discriminative features from the attitude data collected by the attitude sensor, a multiscale convolutional capsule network (MCCN) is proposed. In MCCN, integrating low-level and high-level features in a convolutional neural network (CNN) as multiscale features is conductive to noise reduction and robust feature extraction, and a capsule network (CapsNet) is used to recognize the spatial relationships in attitude data. The extracted multiscale features in CNN and the spatial-relational features in CapsNet are fused for effective fault diagnosis of industrial robots. The performance of MCCN is evaluated by attaching a softmax-based classifier and integrating it into different transfer learning frameworks to diagnose faults in industrial robots under single and variable working conditions, respectively. Fault diagnosis experiments were conducted on a 6-axis series industrial robot and a parallel robot-driven 3D printer. The superiority of the proposed MCCN was demonstrated by comparing its performance with the other feature learning methods.
Glabridin is the main ingredient of hydrophobic fraction in licorice extract and has been shown to have anti-melanogenesis activity in skins. However, the underlying mechanism(s) remain not completely understood. The aim of this study is thus to elucidate the possible mechanisms related to the melanogenesis suppression by glabridin in cultured B16 murine melanoma cells and in UVA radiation induced hyperpigmentation model of BALB/c mice as well. Molecular docking simulations revealed that between catalytic core residues and the compound. The treatment by glabridin significantly downregulated both transcriptional and/or protein expression of melanogenesis-related factors including melanocyte stimulating hormone receptor (MC1R), microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), TYR-related protein-1 (TRP-1) and TRP-2 in B16 cells. Both PKA/MITF and MAPK/MITF signaling pathways were found to be involved in the suppression of melanogenesis by glabridin in B16 cells. Also in vivo glabridin therapy significantly reduced hyperpigmentation, epidermal thickening, roughness and inflammation induced by frequent UVA exposure in mice skins, thus beneficial for skin healthcare. These data further look insights into the molecular mechanisms of melanogenesis suppression by glabridin, rationalizing the application of the natural compound for skin healthcare.
Pathological angiogenesis frequently occurs in tumor tissue, limiting the efficiency of chemotherapeutic drug delivery and accelerating tumor progression. However, traditional vascular normalization strategies are not fully effective and limited by the development of resistance. Herein, inspired by the intervention of endogenous bioelectricity in vessel formation, we propose a wireless electrical stimulation therapeutic strategy, capable of breaking bioelectric homeostasis within cells, to achieve tumor vascular normalization. Polarized barium titanate nanoparticles with high mechano-electrical conversion performance were developed, which could generate pulsed open-circuit voltage under low-intensity pulsed ultrasound. We demonstrated that wireless electrical stimulation significantly inhibited endothelial cell migration and differentiation in vitro. Interestingly, we found that the angiogenesis-related eNOS/NO pathway was inhibited, which could be attributed to the destruction of the intracellular calcium ion gradient by wireless electrical stimulation. In vivo tumor-bearing mouse model indicated that wireless electrical stimulation normalized tumor vasculature by optimizing vascular structure, enhancing blood perfusion, reducing vascular leakage, and restoring local oxygenation. Ultimately, the anti-tumor efficacy of combination treatment was 1.8 times that of the single chemotherapeutic drug doxorubicin group. This work provides a wireless electrical stimulation strategy based on the mechano-electrical conversion performance of piezoelectric nanoparticles, which is expected to achieve safe and effective clinical adjuvant treatment of malignant tumors.
Aqueous zinc-ion batteries (AZIBs) can be one of the most promising electrochemical energy storage devices for being non-flammable, low-cost, and sustainable. However, the challenges of AZIBs, including dendrite growth, hydrogen evolution, corrosion, and passivation of zinc anode during charging and discharging processes, must be overcome to achieve high cycling performance and stability in practical applications. In this work, we utilize a dual-functional organic additive cyclohexanedodecol (CHD) to firstly establish [Zn(H 2 O) 5 (CHD)] ²⁺ complex ion in an aqueous Zn electrolyte and secondly build a robust protection layer on the Zn surface to overcome these dilemmas. Systematic experiments and theoretical calculations are carried out to interpret the working mechanism of CHD. At a very low concentration of 0.1 mg mL ⁻¹ CHD, long-term reversible Zn plating/stripping could be achieved up to 2200 h at 2 mA cm ⁻² , 1000 h at 5 mA cm ⁻² , and 650 h at 10 mA cm ⁻² at the fixed capacity of 1 mAh cm ⁻² . When matched with V 2 O 5 cathode, the resultant AZIBs full cell with the CHD-modified electrolyte presents a high capacity of 175 mAh g ⁻¹ with the capacity retention of 92% after 2000 cycles under 2 A g ⁻¹ . Such a performance could enable the commercialization of AZIBs for applications in grid energy storage and industrial energy storage.
Artificial light-emitting diode (LED) light source, regarded as a front-runner technology for the promoting of plant growth, has attracted much attention toward the burgeoning fertilizer-free indoor plant cultivation. It still remains a challenge that explore a far-red-emitting phosphor of high-thermal stability. Overall, we report a Mn⁴⁺ ion-doped ordered double perovskite tungstates prepared by high-temperature solid-state reaction method in air. The crystal structure, morphology, and fluorescence properties were investigated and discussed in detail. The far-red emission of the optimized CaSrMgWO6:1%Mn⁴⁺, covering the wavelength region of 630–780 nm, matches the absorption ranges of the chlorophyll a and phytochrome (Pfr). The value of Dq/B is estimated to be 2.81. Most notable is the excellent thermal quenching resistance of the Mn⁴⁺ emission, remaining 86.7% at 150 °C, thereby suitably fabricating a far-red LED device. The LED light-driven regulation of the physiological and biochemical changes enables a proof-of-concept garlic cultivation. The growth of weight, stem length, and root length of the garlic was significantly promoted with the extra supply of the far-red light. This work demonstrates that the as-obtained far-red-emitting phosphor holds a promising perspective for the phosphor-converted far-red LED light sources toward the flourishing fertilizer-free indoor plant cultivation.
The investigation of suitable anode materials for sodium-ion batteries (SIBs) is highly appealing in order to tackle the obstacles of large electrode volume variation and sluggish charge kinetic caused by the larger radius of Na⁺ than that of Li⁺. Recently, cobalt phosphides (CoP) have attracted extensive attention for anode materials because of their relatively high theoretical capacity and electric conductivity. In light of that, we propose a new fabrication approach for the synthesis of layered zeolitic imidazolate framework-67 (ZIF-L)-derived CoP nanoparticles encapsulated into N, P co-doped carbon layers and conductive MXene substrate to form sandwich-structure [email protected]@NPC hybrids. Specifically, the MXene and wafer-like ZIF-L hybrids are used as precursor, which is treated with subsequent carbonation with low temperature (435 °C) for a long time of 8 h, and then coupled with phosphidation reaction. The MXene substrate not only provides abundant growing sites for ZIF-L, for avoiding aggregation of CoP nanoparticles, but also enhances the electric conductivity of sandwich-structure hybrid. Furthermore, the in situ formed carbon layer can effectively ensure stable structural integrity by buffering volume expansion and improving overall conductivity. Concurrently, CoP nanocrystals, outer carbon layer, and MXene substrate form stable interface by strong chemical interaction, inducing promoted surface charge transfer kinetic. Consequently, the [email protected]@NPC anode exhibits outstanding rate capability with a highly reversible capacity of 198 mAh/g at 5.0 A/g and long-time cycling performance with 155 mAh/g at 1.0 A/g after 1000 cycles (0.023% capacity loss per cycle).
Biological soft tissues manipulation, including conventional (mechanical) and nonconventional (laser, waterjet and ultrasonic) processes, is critically required in most surgical innervations. However, the soft tissues, with their nature of anisotropic and viscoelastic mechanical properties, and high biological and heat sensitivities, are difficult to manipulated. Moreover, the mechanical and thermal induced damage on the surface and surrounding tissue during the surgery can impair the proliferative phase of healing. Thus, understanding the manipulation mechanism and the resulted surface damage is of importance to the community. In recent years, more and more scholars carried out researches on soft biological tissue cutting in order to improve the cutting performance of surgical instruments and reduce the surgery induced tissue damage. However, there is a lack of compressive review that focused on the recent advances in soft biological tissue manipulating technologies. Hence, this review paper attempts to provide an informative literature survey of the state-of-the-art of soft tissue manipulation processes in surgery. This is achieved by exploring and recollecting the different soft tissue manipulation techniques currently used, including mechanical, laser, waterjet and ultrasonic cutting and advanced anastomosis and reconstruction processes, with highlighting their governing removal mechanisms as well as the surface and subsurface damages.
Organic room-temperature phosphorescence (RTP) with ultralong lifetime and high quantum efficiency is of interest but challenging. Few phosphor systems in the monomer state demonstrate lifetimes over 0.1 s with quantum efficiencies exceeding 10% due to the lack of molecular design principle and qualified molecular system. Here we present a novel class of phosphors based on heteroaromatic sulfone-locked triphenylamine core BTPO with rational subunit modification that displays ultralong RTP in a doped polymer matrix with lifetimes up to 818 ms and quantum efficiencies over 20% simultaneously. The co-win situation is attributed to an efficient and multichannel intersystem crossing (ISC) process arising from narrower singlet-triplet exchange energy and strong spin-orbital coupling interaction between the lowest singlet state (S1) and high-lying triplet states that facilitate numerous triplet excitons generation, as well as a relatively pure (π, π*) configuration for the lowest triplet state (T1), ensuring the small radiative rate of phosphorescence (kp) and consequently ultralong lifetime. Taking advantage of RTP features with the multicolor and diverse lifetime of this phosphor family, the primary application in information encryption is well demonstrated versatilely.
To minimize the effect of optical crosstalk-generated noise (crosstalk), we present a deep learning approach to precisely estimate the full-field displacements for depth-resolved wavelength-scanning interferometry (DRWSI). A deep convolution neural network, where the transformer block is introduced to effectively capture higher-order features of the wrapped phase difference map in a strong noise environment, is applied for phase unwrapping. Furthermore, a binary phase noise map is used to update the loss function in an improved training model, enhancing the network generalization. Finally, the full-field displacements are estimated from phase unwrapping maps with a high signal-to-noise ratio. The simulation and the loading experiment verified that a higher accuracy reconstruction of displacement is implemented using our approach. The contribution of this work can make the DRWSI more practical in quantifying the mechanical property inside the sample.
In this paper, we demonstrate giant and tunable polarization selectivity of circularly polarized light (CPL) in transmission and reflection modes simultaneously by using photosensitive silicon-based zigzag metasurface. At 3.42 THz, the metasurface provides circular dichroism of transmission/reflection (CDT/CDR) of 0.89/−0.83 for forward-incident CPL and −0.86/0.69 for backward-incident CPL. Multipole expansion and Jones matrix deduction are performed to analyze the physical mechanism of polarization selectivity. To verify the actual control effect of polarization selectivity, a dynamic chiral imaging utilizing the proposed structure and its enantiomer is provided. By applying extra optical pumping to silicon, the switching between showing and hiding pre-designed pattern in transmission field is realized without refabricating the structures. The proposed metasurface with high-efficiency circular polarization selectivity has profound implications for photonic integrated devices.
An injection-locked optoelectronic oscillator (OEO) based on frequency-conversion delay matching is proposed and experimentally demonstrated. There are two branches in the proposed OEO, where one branch is used to maintain the oscillation in the cavity, and the other one based on frequency conversion is used to generate a pure frequency-converted injection signal. Owing to the frequency-conversion-based injection locking effect, the side-mode suppression ratio of the proposed OEO can be greatly improved. In addition, the phase noise deterioration induced by the externally-injected signal can be effectively eliminated when the time delays of the two branches are well matched. In the experiment, a pure single-tone microwave signal at 9.99998 GHz is generated, whose side-mode suppression ratio and phase noise are measured to be 74.4 dB and −130 dBc/[email protected] kHz, respectively.
In this research study, a biofuel cell system for simultaneous electricity and heat production is modeled and investigated from the perspectives of energy, exergy, and economics. The polymer-based fuel cell in this study is employed with nanomaterial Pt for enhanced performance. The system includes the primary components of a gasifier, a polymer membrane fuel cell, and a two-stage organic Rankine cycle. Additionally, the impacts of employing the Rankine cycle to recover the waste heat generated by the fuel cell on system efficiency have been explored. Five series of binary combinations for the first and second cycles of the organic Rankine system were explored during this investigation. Among them, the first and second cycles using propane and ethane, respectively, have the maximum energy effectiveness and exergy. The fundamental and effective variables were found. Eventually, the system was optimized using the objective functions of exergy cost and efficiency after conducting a thermodynamic and economic analysis of the cycle using parametric assessment. Ultimately, the most acceptable point of system design, taking both cost and exergy efficiency into account, results in exergy efficiency and cost of 39.86 percent and 32.038 $/h, respectively.
Graphite is a fascinating material with unique properties, thus making it irreplaceable for a wide range of applications. However, its current processing route is highly energy demanding as it requires dwelling for several hours at high temperatures (2500-3000°C). We report on the near full consolidation (relative density greater than 95%) at room temperature of graphite flakes under a mild uniaxial or isostatic pressure (100-500 MPa). The application of an external pressure promoted the formation of van der Walls bonds between the flakes, and the consolidation (pore removal) was mostly achieved by interplanar slipping. Despite the room temperature processing, with embodied energy below 1 MJ/kg, the resulting compact had in plane electrical and thermal conductivities as high as 0.77×10⁶ S/m and 620 W/m·K (exceeding commercial isotropic graphite ≈0.09×10⁶ S/m and 120 W/m·K). The bulks were thermally stable up to 1800°C. Because of the reversible nature on the van der Walls bonding, the cold pressed pellets were fully recyclable (i.e., easily milled and re-shaped) with a mild degradation of the electrical conductivity from 0.77 to 0.19×10⁶ S/m after ten cycles.
Ionic conduction has been well-documented in three typical layered perovskite materials, namely Ruddlesden-Popper-type, Dion-Jacobson-type, and Aurivillius-type. In the present work, the oxide ion conduction was reported in the Sr2Nb2O7 material which also adopts a layered perovskite-related structure but does not fall into any of the above-mentioned three typical structures. The results revealed that the oxide ion conduction originated from the slight reduction of Nb⁵⁺ ions during the high-temperature synthesis process, as the sample prepared under a pure oxygen atmosphere showed more than one order of magnitude lower conductivity than the sample prepared under an ambient atmosphere. The bond-valence-based method was applied to investigate the oxide ion migration mechanism, and revealed a two-dimensional pathway within the perovskite slabs. The discovery of this new oxide ion conductor will stimulate extensive exploitation and fundamental research on other layered perovskite-related materials.
Despite the well-recognized advantages of Ultrafast High-temperature Sintering (UHS) based on the application of a graphite felt/paper heater, the technology, however, remains mostly suitable to consolidate thin-shaped samples. This work proposes a novel UHS configuration based on the graphite powder medium (P-UHS) to obtain much larger and complex-shaped products. As a proof-of-concept, nearly full dense and homogeneous macro-/microstructures bulk alumina ceramics with size of 10×10×25 mm³ were densified under a heating rate of 770 °C/min. In comparison with the conventional firing (5 °C/min) approach, the combination of ultrafast heating rate and high temperature (≥1772 °C) induced a very high densification rate mostly driven by lattice diffusion. The very rapid sintering cycle also prevented any detectable carbon contamination. Indeed, the proposed P-UHS approach combines together fine tuning of the microstructures and ultralow energy requirements.
To rise the efficiency of energy capture for semi-active flapping airfoils power generator at low flow speed, a flow control approach via leading edge slots is carefully examined using numerical method. The energy capture performances of airfoil that affected by slot types formulated with different incline angles are analyzed. The results show that the energy capture power and efficiency of the semi-active flapping airfoils can be improved by cutting appropriate slots on the leading edge of airfoil. Among the carried-out calculations, when the incline angle is from 15° to 17°, better energy capture performances are obtained compared with original airfoil without slots, and 17° incline slots configuration is the best with 9.23% higher mean power coefficient. By further examination of the flow structure, it can be found that the 17° incline slot can make leading edge vortex reattached to the surface of flapping airfoil and evolve tardily along the airfoil surface, to keep flapping airfoil with high lift in the process of reciprocating flapping, which makes the flapping airfoil possessing better energy capture performances.
Methane seeping induced by natural gas hydrate dissociation is ubiquitous in deep-sea environment, which influences the global methane and carbon budget. Nevertheless, the phase equilibrium characteristics that control the stability of hydrate formation during the bubble ebullition process in the in-situ multi-component environment remain unclear. “Haima” cold seep is a typical active methane seeping environment associated with abundant methane hydrate, which necessitates unveiling the potential and stability of methane hydrate formation. This work investigated the hydrate phase equilibrium conditions based on the in-situ water depth with practical ion categories and concentrations for the first time. Results show that Sr2+ is an important ion that governs the thermal stability of methane hydrate. Mechanism of different ions categories (Ca2+, Mg2+, and Sr2+) effect on hydrate equilibria can be elucidated by the difference of charge and radius of the ion. Slightly difference of in-situ ion concentrations within the same salinity exerts on unobvious effect on hydrate formation. Moreover, the hydrate stability with H2S-bearing environment coupled with the anaerobic oxidation of methane in the deep-sea floor was enhanced compared to the CO2-bearing environment associated with aerobic oxidation of methane. Furthermore, thermal dynamic conditions of hydrate formation were less rigorous than that in the single methane environment. The response law of hydrate phase transition enthalpy was almost consistent with the phase equilibrium change. This work can give important fundamentals for the estimation of hydrate resources in the practical environment, and have insights for methane capture and fixation in the methane seeps.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.