The development of inexpensive electrode materials with a high volumetric capacity and long cycle-life is a central issue for large-scale lithium-ion batteries. Here, we report a nanostructured ...porous Fe2N anode fully encapsulated in carbon microboxes (Fe2N@C) prepared through a facile confined anion conversion from polymer coated Fe2O3 microcubes. The resulting carbon microboxes could not only protect the air-sensitive Fe2N from oxidation but also retain thin and stable SEI layer. The appropriate internal voids in the Fe2N cubes help to release the volume expansion during lithiation/delithiation processes, and Fe2N is kept inside the carbon microboxes without breaking the shell, resulting in a very low electrode volume expansion (the electrode thickness variation upon lithiation is ∼9%). Therefore, the Fe2N@C electrodes maintain high volumetric capacity (1030 mA h cm–3 based on the lithiation-state electrode volume) comparable to silicon anodes, stable cycling performance (a capacity retention of over 91% for 2500 cycles), and excellent rate performance. Kinetic analysis reveals that the Fe2N@C shows an enhanced contribution of capacitive charge mechanism and displays typical pseudocapacitive behavior. This work provides a new direction on designing and constructing nanostructured electrodes and protective layer for air unstable conversion materials for potential applications as a lithium-ion battery/capacitor electrode.
Accurate crop phenology information is essential for precision farming and agricultural productivity improvement. In recent years, in-situ equipment on crop phenology observation has been boosted, ...which generates high-quality real-time pictures on capturing vegetation phenological changes. However, due to the limited number of ground sites, it is impossible to measure large-scale crop phenology with local observations. Complementary, the freely available Sentinel satellites with high revisit frequency provide an opportunity to map accurate crop phenology at an unprecedented fine spatial scale. Because of the differences in viewing angle and range, the consistency of crop phenological stages varies between satellite and ground observations. To fill the gap between satellite and ground observations, we developed a spatial-aware scheme to integrate SAR and optical time-series data for accurate crop phenology tracking. To be specific, we propose a new deep learning model called Deep-CroP framework to improve the alignment between satellite and ground observations on crop phenology. The experiment results on selected ground sites demonstrate that the proposed Deep-CroP is able to accurately identify crops phenology and narrow the discrepancies from 30+ days to as high as several days. In addition, we applied the Deep-CroP to large-scale Sentinel time-series to map spatial patterns of phenology at fine resolution imagery on two study areas (i.e., TA1 and TA2). In general, the potential of satellites time-series for ground-level crop phenology observation is verified. Also, the consistency between satellite and PhenoCam observations is expected to be further improved.
•Deep integration of Optical-SAR time-series for crop phenology tracking.•SAR imagery boost the consistency of ground and optical satellite observations.•Deep-CroP model aims to extract phenology parameter with spatial-aware deep features.
Tungsten is a high-value resource with a wide range of applications. The tungsten metal is produced via ammonium paratungstate, which is a multi-stage process including leaching, conversion, ...precipitation, calcination, and reduction. A short process to produce tungsten metal from the electrolysis of molten sodium tungstate has been demonstrated. However, sodium tungstate cannot be directly produced from wolframite in the conventional hydrometallurgical process. There was no information reported in the literature on producing sodium tungstate directly from tungsten concentrates. The present study proposed a simple and low-cost process to produce sodium tungstate by high-temperature processing of wolframite. The mixtures of wolframite, sodium carbonate, and silica were melted in air between 1100 and 1300 °C. High-density sodium tungstate was easily separated from the immiscible slag, which contained all impurities from wolframite, flux, excess sodium oxide, and dissolved tungsten oxide. The slag was further water leached to recover sodium tungstate in the solution. Effects of Na2CO3/Ore and SiO2/Ore ratios, temperature, and reaction time on the recovery of tungstate and the purity of sodium tungstate were systematically studied. Sodium tungstate containing over 78% WO3 was produced in the smelting process, which is suitable for the electrolysis process. The experimental results will provide a theoretical basis for the direct production of sodium tungstate from wolframite. The compositions of the WO3-containing slags and sodium tungstate reported in the present study fill the knowledge gap of the tungsten-containing thermodynamic database. Further studies to use complex and low-grade tungsten concentrates to produce sodium tungstate are underway.
Tin‐based electrode
s offer high theoretical capacities in lithium ion batteries, but further commercialization is strongly hindered by the poor cycling stability. An in situ reduction method is ...developed to synthesize SnO2 quantum dots@graphene oxide. This approach is achieved by the oxidation of Sn2+ and the reduction of the graphene oxide. At 2 A g−1, a capacity retention of 86% is obtained even after 2000 cycles.
Regulatory focus theory (RFT) has been regarded as an important theory for understanding customer behavior in e-commerce; however, there is a significant gap between theoretical analysis with RFT and ...its practical applications. In particular, there is little research on how to identify the chronic regulatory focus of customers; as such, it is difficult to apply RFT in e-commerce operations. To fill this research gap, we propose an innovative method to operationalize customer regulatory focus from the affective dimension, leading to operationalized regulatory focus (ORF). In this regard, our study spearheads a new avenue of research on how social theories can be operationalized and applied in e-commerce operations. We first identify customers' chronic regulatory focus (i.e., promotion focus or prevention focus) based on online review data using text mining, leading to an innovative method we refer to as "regulatory focus discovery." Then, we validate the computed results on regulatory focus by surveying corresponding customers included in the same dataset. Finally, we evaluate the applicability of ORF via an econometric analysis. In this article, we demonstrate that it is possible to compute regulatory focus of specific customers for the purpose of assessing their purchasing tendency. The theoretical and practical implications of ORF are discussed.
Virtual process engineering (VPE) aims to redefine the roadmap for process scaling-up and optimization, from stepwise experiments to high-performance computer simulations. This is a long-cherished ...dream of chemical engineers, but requires high standards of Accuracy (the agreement between the simulation and the real process), Capability (the computational speed, scale, and resolution of the simulation), and Efficiency (cost-effective and easy to use), in short, ACE. For complex processes such as gas–solid fluidization, the gap between state-of-the-art simulations and VPE is still huge in terms of ACE. However, the work reported in this paper narrows this gap significantly. In this study, a coarse-grained discrete particle method (DPM) defined by the energy-minimization multi-scale (EMMS) model is deployed for high-resolution simulations of fluidized beds, with the gas- and solid-phase equations solved concurrently by CPUs and GPUs in a heterogeneous supercomputing system. With systematic optimization of the model, numerical method, software, and hardware, we are able to simulate lab- to pilot-scale fluidized beds at quasi-realtime speed, and conduct virtual experiments on such systems. This enables very-long-time simulations to obtain important engineering parameters such as the particle residence time distribution, attrition and deactivation indexes. This work demonstrates that the industrial application of VPE is almost on the horizon.
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•DEM and CFD equations are solved concurrently by CPUs and GPUs.•Simulation is coupled with on-line visualization and operation control.•Pilot-scale CFB riser is simulated in quasi-real-time interactively•Lab-scale CFB is simulated in 3D for the full loop using EMMS-DPM•Discrete simulation of slow process for hours of physical time.
For the bidirectional wireless power transfer (BWPT) technology, the phase synchronization between the transmitting and receiving converters is very essential and difficult to achieve by wireless ...communication between two sides because the delay and data transfer interval of wireless communication severely influence the control performance. This article proposes a novel control strategy for BWPT, which can achieve the phase synchronization and maximum efficiency point tracking independent of the real-time wireless communication. To solve the overshoot and oscillation problem incurred by the proposed control strategy and the nature of the system itself, the dynamics of a series-series compensated BWPT system is then analyzed and a small-signal model of this system is derived based on the generalized state space averaging and extended describing function methods. Using the small-signal model, a BWPT control system based on the proposed control strategy is designed and optimized. The validity of the proposed strategy and the performance of the control system are verified experimentally using a 3.3-kW prototype system.
Hard carbon finds critical applications in potassium-ion batteries (PIBs) anodes because of its attractive advantages including low cost and high conductivity. However, the sluggish reaction kinetics ...and structural instability caused by large K+ intercalation/deintercalation limit their storage capability and cycling life. Herein, active sites enriched hard carbon porous nanobelts (NOCNBs) for enhanced K+ storage are constructed from mineralized shrimp shells via a self-template assisted pyrolysis strategy. The NOCNBs possess multiscale structure with hierarchical micro/meso/macro-pores, high-level pyrrolic/pyridinic-N and O dual-doping, and large interlayer spacing. Hence, the NOCNBs deliver a high capacity of 468 mAh g−1 at 50 mA g−1 and long cycling life (277 mAh g−1 at 1000 mA g−1 over 1600 cycles), representing one of the best storage capability and cycling stability among the reported carbonaceous electrodes. Density functional theory calculations and kinetic analysis demonstrate that the abundant active sites within NOCNBs can strengthen K adsorption and diffusion, facilitating capacitive-adsorbed storage. The in-situ X-ray diffraction reveals the potassium intercalation mechanism in hard carbon for the first time. Furthermore, they exhibit a superior capacity of 89 mAh g−1 at 100 mA g−1 for potassium dual-ion batteries (PDIBs). This work opens up a new avenue for constructing porous hard carbon to achieve excellent K+ storage.
Active sites enriched hard carbon porous nanobelts are constructed via self-template assisted structural regulation strategy. The nanobelts weaved by carbon nanotube array can behave as favorable anodes for potassium-ion batteries (468 mAh g−1 at 50 mA g−1, 277 mAh g−1 over 1600 cycles at 1000 mA g−1) and potassium dual-ion hybrid batteries (89 mAh g−1). Display omitted
•Active sites enriched hard carbon porous nanobelts (NOCNBs) for enhanced K+ storage are constructed via a self-template assisted pyrolysis strategy.•The NOCNBs possess multiscale structure with hierarchical micro/meso/macro-pores, high-level pyrrolic/pyridinic-N and O dual-doping, and large interlayer spacing.•Density functional theory calculations and kinetic analysis demonstrate that the NOCNBs can strengthen K adsorption and diffusion, facilitating capacitive-adsorbed storage.•A high capacity of 468 mAh g-1 at 50 mA g-1 and long cycling life (277 mAh g-1 at 1000 mA g-1 over 1600 cycles) are achieved.
► β-Carotene, astaxanthin, capsanthin, and bixin were chosen to treat K562 cells. ► Carotenoids decreased the viability of leukemia K562 cells, induced cell apoptosis, and interfered with cell cycle ...progression in dose- and time-dependent manners. ► Pretreatment with GW9662, a potent antagonist of PPARγ, partly attenuated the inhibition of K562 cells by carotenoid. ► Carotenoids up-regulated the expression of PPARγ, p21 and Nrf2 but down-regulated the expression of cyclin D1 in a dose-dependent manner. ► PPARγ signaling pathways and Keap1-Nrf2/EpRE/ARE signaling pathway were involved in the inhibition of K562 cell proliferation by carotenoids.
As one of the main micronutrients in vegetables and fruit carotenoids are almost daily intaken in significant quantity. Although the pharmacological roles of carotenoids in the prevention and reduction of cancer incidence have received more and more attention, the exact molecular mechanisms underlying anticancer effects of carotenoids remain unclear yet. Activated peroxisome proliferator-activated receptor gamma (PPARγ) plays an inhibitory role in cancer cell proliferation and growth. Involvement of PPARγ in the growth inhibition of leukemia K562 cells by carotenoids was investigated in the present study. The results demonstrated that β-carotene, astaxanthin, capsanthin, and bixin inhibited the proliferation and decreased the viability of leukemia K562 cells in dose- and time-dependent manners, induced cell apoptosis, and interfered with cell cycle progression. Pretreatment with GW9662, a potent antagonist of PPARγ, partly attenuated the inhibition of K562 cell proliferation by the four carotenoids at 8
μM. These carotenoids up-regulated the expression of PPARγ and p21 and down-regulated the expression of cyclin D1 in a dose-dependent manner. In addition, β-carotene, astaxanthin, capsanthin and bixin also up-regulated the expression of Nrf2, an important transcription factor in Keap1-Nrf2/EpRE/ARE signaling pathway. It appears to us that PPARγ signaling pathways and Keap1-Nrf2/EpRE/ARE signaling pathway were involved in the inhibition of K562 cell proliferation by carotenoids and the up-regulation of PPARγ expression at least partly contributed to the antiproliferative effects of β-carotene, astaxanthin, capsanthin, and bixin on K562 cells.
Strong and ductile sodium alginate (SA) reinforced polyacrylamide (PAM)/xanthan gum (XG) double network ionic hydrogels were constructed for stress sensing and self-powered wearable device ...applications. In the designed network of PXS-Mn+/LiCl (short for PAM/XG/SA-Mn+/LiCl, where Mn+ stands for Fe3+, Cu2+ or Zn2+), PAM acts as a flexible hydrophilic skeleton, and XG functions as a ductile second network. The macromolecule SA interacts with metal ion Mn+ to form a unique complex structure, significantly improving the mechanical strength of the hydrogel. The addition of inorganic salt LiCl endows the hydrogel with high electrical conductivity, and meanwhile reduces the freezing point and prevents water loss of the hydrogel. PXS-Mn+/LiCl exhibits excellent mechanical properties and ultra-high ductility (a fracture tensile strength up to 0.65 MPa and a fracture strain up to 1800%), and high stress-sensing performance (a high GF up to 4.56 and pressure sensitivity of 0.122). Moreover, a self-powered device with a dual-power-supply mode, i.e., PXS-Mn+/LiCl-based primary battery and TENG, and a capacitor as the energy storage component was constructed, which shows promising prospects for self-powered wearable electronics.
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