batterydata/paper-abstracts huggingface dataset:
Three cathode compounds for lithium ion batteries, LiMn2O4, LiMn1.95Si0.05O4 and LiMn1.9Ga0.1O4 have been synthesized by the freeze-drying method. All samples present partially sintered particles of 80 nm average size, corresponding to single crystalline phases with cubic spinel structure. The substitution of a little portion of Mn(IV) by Si(IV) in the crystal framework leads to more expanded and regular MnO6 octahedra, whereas the replacement of some Mn(III) by Ga(III) induces the opposing effect. The ESR measurements support the effectiveness of doping as an evolution of the width of the resonance signal with the composition is observed. A complete magnetic study has been carried out, including ac and dc magnetic susceptibility measurements at different fields, FC and ZFC, and magnetization versus field. Due to the in-built magnetic frustration in spinel structure and the competition between different exchange pathways, the insertion of small quantities of dopants causes significant differences in the magnetic behaviour. The electrochemical study has revealed very good values of specific capacity for LiMn1.95Si0.05O4 reaching 146 mA h g− 1 and 139 mA h g− 1 at C/10 and 1C rates, respectively. A capacity retention up to 75% has been observed for the three samples after 300th cycles.
Among the hydrodynamic forces experienced by intertidal organisms, drag and the impingement force are thought to have the greatest effect on macroalgae. These forces are modified by biotic factors such as algal morphology, reconfiguration, and the presence of a canopy. However, much of what is known about the hydrodynamics of macroalgae has been garnered from low-velocity laboratory flume studies. Few field studies have measured drag and none have directly measured the effects of the canopy on force. To examine in situ hydrodynamic forces imposed on the turf forming macroalga Chondrus crispus, compact digital force sensors were developed that measure and record the 3-dimensional force imposed on a macroalga without disturbing the surrounding canopy. Sensors were positioned within natural Chondrus beds and the effects of the canopy, algal morphology, and sea state on in situ hydrodynamic force were examined. Additionally, the predictions of a new model for drag on flexible macroalgae were tested by simultaneously measuring force and water velocity. Digital force recordings indicated that Chondrus only experience drag; lift and impingement force were negligible in all combinations of factors. Canopies significantly reduced drag by 15–65%. Morphology and size also influenced drag, such that lower forces were imposed on small planar algae than large arborescent individuals. Further, planar algae experienced low drag in all combinations of sea and canopy state, indicating that these individuals may not be as susceptible to wave disturbance as arborescent individuals. Overall, these data indicate that the ability for Chondrus to grow large, arborescent individuals is dependent on the drag reducing properties of the canopy, while more hydrodynamically harsh habitats may be accessible to planar morphologies. Additionally, these data suggest that drag models for canopy forming macroalgae must incorporate the effects of the canopy to predict drag accurately in situ.
Existing term extraction systems have predominantly targeted large and well-written document collections, which provide reliable statistical and linguistic evidence to support term extraction. In this article, we address the term extraction challenges posed by sparse, ungrammatical texts with domain-specific contents, such as customer complaint emails and engineers’ repair notes. To this aim, we present ExtTerm, a novel term extraction system. Specifically, as our core innovations, we accurately detect rare (low frequency) terms, overcoming the issue of data sparsity. These rare terms may denote critical events, but they are often missed by extant TE systems. ExtTerm also precisely detects multi-word terms of arbitrarily lengths, e.g. with more than 2 words. This is achieved by exploiting fundamental theoretical notions underlying term formation, and by developing a technique to compute the collocation strength between any number of words. Thus, we address the limitation of existing TE systems, which are primarily designed to identify terms with 2 words. Furthermore, we show that open-domain (general) resources, such as Wikipedia, can be exploited to support domain-specific term extraction. Thus, they can be used to compensate for the unavailability of domain-specific knowledge resources. Our experimental evaluations reveal that ExtTerm outperforms a state-of-the-art baseline in extracting terms from a domain-specific, sparse and ungrammatical real-life text collection.
Spinel cobalt ferrite (CoFe2O4) thin films have been fabricated by 355nm reactive pulsed laser deposition on stainless steel substrates. XRD and SEM analyses showed that the CoFe2O4 films exhibited a polycrystalline structure and were composed of nanoparticles with an average size of 80nm. At 1C rate, the initial irreversible capacity of polycrystalline CoFe2O4 film electrode cycled between 0.01 and 3.0V reached 1280mAh/g. After 20 cycles, the reversible discharge capacities decreased and sustained about 610mAh/g. The diffusion coefficient of Li ion for CoFe2O4 films was determined by ac impedance method, and the average value was estimated to be 1.1 × 10−13 cm2/S. Based on ex situ XRD, SEM and XPS data, the electrochemical mechanism of CoFe2O4 film with lithium upon cycling was proposed. During the first discharge, the amorphization process of CoFe2O4 film electrode is accompanied with the reduction of Co2+ and Fe3+ into metal Co and Fe, respectively, and then the reversible oxidation/reduction processes of Co, Fe and Li2O take place in the subsequent charge/discharge cycles.
ABSTRACT Pure LiFePO4 and the nano-sized LiFe1−x Mg x PO4-C (x =0.00, 0.02, 0.04, 0.06 and 0.08) cathode materials have been prepared and investigated for Li-ion batteries. Samples were synthesized by handy and cheap sol–gel-assisted carbothermal reduction method. X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and inductively coupled plasma (ICP) have been used to study the crystal structure, morphology and chemical composition of all produced materials. XRD findings reveal the slight decrease in crystal lattice of LiFePO4 after Mg2+ doping. Phase pure samples crystallize in the olivine-type structure with a linear relationship between lattice parameters (a, b and c) and chemical composition. The FE-SEM images have proved that Mg-doped particles are not agglomerated and the particle sizes (40–60nm) are able to compete with the literature. The synthesized small particles of the sol–gel-assisted carbothermal reduction process lead to a superior capacity in comparison to a common solid-state synthesis. For a Mg content of 0.04% the capacity is reached to a higher level (167mAhg−1) and good capacity retention of 97.0% over 300 cycles is observed. Although doping with Mg has a remarkable effect on improving its electronic or ionic mobility, but serious electrochemical degradation will occur when its doping density is beyond 0.04mol. The cycling voltammogram (CV) shows that Mg-doped LiFe0.96Mg0.04PO4-C electrode has improved electrical conductivity and diffusion coefficient of Li+ ions, in which Mg2+ is related to effectively act as a pillar in crystal lattice structure to prevent the collapse during lithium intercalation process.
Recent evidence suggests that young rodents submitted to high fructose (FRU) diet develop metabolic, and cognitive dysfunctions. However, it remains unclear whether these detrimental effects of FRU intake can also be observed in middle-aged mice. Nine months-old C57BL/6 female mice were fed with water (Control) or 10% FRU in drinking water during 12 weeks. After that, metabolic, and neurochemical alterations were evaluated, focusing on neurotransmitters, and antioxidant defenses. Behavioral parameters related to motor activity, memory, anxiety, and depression were also evaluated. Mice consuming FRU diet displayed increased water, and caloric intake, resulting in weight gain, which was partially compensated due to decreased food pellet intake. FRU fed animals displayed increased plasma glucose, and cholesterol levels, which was not observed in overnight-fasted animals. Superoxide dismutase (SOD), and catalase (CAT) activities were markedly decreased in the prefrontal cortex of animals receiving FRU diet, while glutathione peroxidase (GPx) slightly increased. Liver (lower GPx), striatum (higher SOD and lower CAT), and hippocampus (no changes) were less impacted. No changes were observed in glutathione reductase, and thioredoxin reductase activities, two ancillary enzymes for peroxide detoxification. FRU intake did not alter serotonin, dopamine, and norepinephrine levels in the hippocampus, prefrontal cortex, and striatum. No significant alterations were observed in working, and short-term spatial memory; and in anxiety- and depressive-like behaviors in animals treated with FRU. Increased locomotor activity was observed in FRU-fed middle-aged mice, as evaluated in the open field, elevated plus-maze, Y maze, and object location tasks. Overall, these results demonstrate that high FRU consumption can disturb antioxidant defenses, and increase locomotor activity in middle-aged mice, open the opportunity for further studies to address the underlying mechanisms related to these findings.
Tremendous efforts have been made to design the cathode of Li–S batteries to improve their energy density and cycling life. However, challenges remain in achieving fast electronic and ionic transport while accommodating the significant cathode volumetric change, especially for the cathode with a high practical mass loading. Here we report a cathode architecture, which is constructed by burning lithium foils in a CS2 vapour. The obtained structure features crystalline Li2S nanoparticles wrapped by few-layer graphene (Li2S@graphene nanocapsules). Because of the improvement on the volumetric efficiency for accommodating sulfur active species and electrical properties, the cathode design enables promising electrochemical performance. More notably, at a loading of 10 mgLi2S cm−2, the electrode exhibits a high reversible capacity of 1,160 mAh g−1s, namely, an area capacity of 8.1 mAh cm−2. Li2S@graphene cathode demonstrates a great potential for Li-ion batteries, where the Li2S@graphene-cathode//graphite-anode cell displays a high capacity of 730 mAh g−1s as well as stable cycle performance.
Hierarchically structured Li4Ti5O12-TiO2 (LTO-TiO2) composites are synthesized using a facile hydrothermal approach upon reaction time control. With control over the time of hydrothermal reaction at 18h, a hierarchical dual-phase LTO-TiO2 composite with appropriate amount of anatase TiO2 can be obtained, and it possesses a uniform carambola-like framework assembled by numerous ultrathin nanosheets, which enable a relatively large specific surface area, along with abundant interlayer channels to favor electrolyte penetration. When used as anode materials for lithium-ion batteries, such carambola-like LTO-TiO2 composite exhibits remarkably improved capacity, high-rate capability, and cycling stability over other LTO-TiO2 samples, which are synthesized at different time of hydrothermal reaction. Specifically, it deliveries a discharge capacity as high as 115.1 and 91.2mAhg−1 at a very high current rate of 20 and 40C, respectively, while a stable reversible capacity of 171.7mAhg−1 can be retained after 200 charge-discharge cycles at 1C, corresponding to 88.6% capacity retention. The excellent electrochemical performances benefit from the unique hierarchical carambola-like structure together with the mutually complementary intrinsic advantages between LTO and TiO2. The robust and porous nanosheets-assembled LTO-TiO2 framework not only offers a shorter transport pathway for electron and Li-ion migration within this composite material, but also is able to alleviate the structure distortion during the fast Li-ion insertion/extraction process. The work described here shows that the hierarchical carambola-like LTO-TiO2 composite is a promising anode material for high-power and long-life lithium-ion batteries.
Redox electrode materials, including transition metal oxides and electronically conducting polymers, are capable of faradaic charge transfer reactions, and play important roles in most electrochemical energy storage devices, such as supercapacitor, battery and supercapattery. Batteries are often based on redox materials with low power capability and safety concerns in some cases. Supercapacitors, particularly those based on redox inactive materials, e.g. activated carbon, can offer high power output, but have relatively low energy capacity. Combining the merits of supercapacitor and battery into a hybrid, the supercapattery can possess energy as much as the battery and output a power almost as high as the supercapacitor. Redox electrode materials are essential in the supercapattery design. However, it is hard to utilise these materials easily because of their intrinsic characteristics, such as the low conductivity of metal oxides and the poor mechanical strength of conducting polymers. This article offers a brief introduction of redox electrode materials, the basics of supercapattery and its relationship with pseudocapacitors, and reviews selectively some recent progresses in the relevant research and development.
The rational design and controllable synthesis of sulfur cathode with high sulfur content, superior structural stability and fascinating electrochemical properties is a vital step to realize the large-scale application of rechargeable lithium-sulfur (Li-S) batteries. However, the electric insulation of elemental sulfur and the high solubility of lithium polysulfides are two intractable obstacles to hinder the success of Li-S batteries. In order to overcome aforementioned issues, a novel strategy combined supercritical CO2 fluid technology and biotemplating method is developed to fabricate Ni(OH)2 modified porous carbon microspheres as sulfur hosts to ameliorate the electronic conductive of sulfur and enhance simultaneously the physical and chemical absorptions of polysulfides. This elaborately designed Ni(OH)2@PYC/S composite cathode exhibits high reversible discharge capacity (1335 mAh g−1 at 0.1 C), remarkable cyclic stability (602 mAh g−1 after 200 cycles at 0.2 C) and superior rate capability, which is much better than its PYC/S counterpart. These results clearly demonstrate that the advanced porous carbon with good conductivity and the polar Ni(OH)2 coating layer with strong trapping ability of polysulfides are responsible for the enhanced electrochemical performance.
We evaluated poly(acrylonitrile-methyl methacrylate) (AMMA, AN/MMA=94:6) as a binder for the graphite anode and the LiMn2O4 cathode of Li-ion batteries by studying the cycling performance of lithium half-cells. The results showed that, using AMMA binder, both graphite and LiMn2O4 could be cycled well in 1m LiPF6 3:3:4 (weight) PC/EC/EMC electrolyte with less capacity fading. AMMA is chemically more stable than poly(vinylidene fluoride) (PVDF) against the lithiated graphite. More importantly, AMMA can help graphite to form a stable solid electrolyte interface (SEI) film. An impedance study showed that the SEI film formed with AMMA is more stable than the one formed with PVDF. Therefore, self-delithiation of the lithiated graphite can be reduced by use of AMMA instead of PVDF, which improves the storage performance of Li-ion batteries.
LiFePO4/C composite cathode materials were synthesized by carbothermal reduction method using inexpensive FePO4 as raw materials and glucose as conductive additive and reducing agent. The precursor of LiFePO4/C was characterized by differential thermal analysis and thermogravimetry. The microstructure and morphology of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and particle size analysis. Cyclic voltammetry (CV) and charge/discharge cycling performance were used to characterize their electrochemical properties. The results showed that the LiFePO4/C composite synthesized at 650°C for 9h exhibited the most homogeneous particle size distribution. Residual carbon during processing was coated on LiFePO4, resulting in the enhancement of the material's electronic properties. Electrochemical measurements showed that the discharge capacity first increased and then decreased with the increase of synthesis temperature. The optimal sample synthesized at 650°C for 9h exhibited a highest initial discharge capacity of 151.2mAhg−1 at 0.2C rate and 144.1mAhg−1 at 1C rate with satisfactory capacity retention rate.
The Adverse Outcome Pathway (AOP) conceptual framework has been presented as a logical sequence of events or processes within biological systems which can be used to understand adverse effects and refine the current risk assessment practice. This approach shifts the risk assessment focus from traditional apical endpoints to the development of a mechanistic understanding of a chemicals effect at a molecular and cellular level. In order to obtain this level of detail, chemistry in all its disciplines has a key role to play. Measurement techniques will be important in understanding chemical characterisation, free concentration and exposure at the site of interest. Such measurements will be vital in developing structure-based toxicological alerts and informing predictive models. This paper explores the areas where chemistry will be influential in the development of AOPs.
In this work, surface characterization and electrochemical measurement were employed to investigate the effects of magnetic field (MF) on the corrosion of Q235 carbon steel in a NaCl solution containing sulphate-reducing bacteria (SRB) or extracellular polymeric substances (EPS). Results demonstrated that a 150 mT MF enhanced steel corrosion in a SRB-containing NaCl solution by 202% calculated from weight loss with pitting corrosion as the main corrosion type. Either EPS or MF rendered steel corrosion, but a synergistic interaction between MF and EPS boosted up steel corrosion. This synergistic enhancement could be referred to the alteration in orientation of EPS induced by MF. The presence of higher percentage of chloride ions on the carbon steel surface manifested that MF initiated the erosion of chloride ions on the carbon steel coupon.
Solar cells that combine nanotechnology with plastic electronics are emerging with the development of a semiconductor-polymer PV device. Researchers at the Lawrence Berkeley National Laboratory and the University of California at Berkeley claim such hybrid cells will be cheaper and easier to make than semiconductors, and could be made in the same, nearly infinite variety of shapes as pure polymers.
Fine particle sulfate was measured continuously for 90 consecutive days, from August through October 1999, at Big Bend National Park. Measurements were made with a prototype integrated collection and vaporization cell, whereby particles are humidified and collected by impaction onto a metal strip and analyzed in place by flash-vaporization and pulsed fluorescence detection of the evolved sulfur dioxide. The time resolution was 12min. Sulfate values are compared to 24-h integrated filter measurements. Time variation in observed concentrations are compared to hourly measurements of dry particle size distributions and to nephelometry at ambient humidity. For most of the study period the sulfate was the major constituent of the accumulation mode aerosol. The sulfate scattering cross section as a function of relative humidity is inferred by comparisons among these measurements using a two-component fine particle model wherein the nonsulfate accumulation mode volume is attributed to nonhygroscopic components.
Performance characteristics of a lead–acid cell with electrodeposited lead and lead dioxide electrodes on carbon are evaluated in aqueous sulfuric acid at concentrations ranging from 1 to 4 M. The discharge capacity is practically independent of the discharge rate within the current range studied (∼1 to 15 mA cm−2). The capacity increases with cycling, possibly due to slow attainment of a ‘spongy’ character for the negative electrode active mass. The capacity also increases with the amount of deposition, reaching a more or less limiting value beyond an optimum deposition. Steady-state discharge behavior, represented by a voltage plateau, shows a nearly Nernstian response, which indicates that the basic electron-transfer processes are quite fast. Experiments involving less than full charge–discharge cycles showed the charging efficiency to pass through a maximum with charging current.
Vanadium oxide/polyaniline nanotubes were produced by cationic exchange between hexadecylamine and polyaniline after the synthesis of vanadium oxide nanotubes by sol–gel method followed by hydrothermal treatment. The local structure of this hybrid material was studied by high-resolution transmission electron microscopy, infrared and Raman spectroscopy and small angle X-ray diffraction technique. The results show that polyaniline is intercalated in the interlamellar space of the vanadium oxide nanotube forming a hybrid material with defined morphology. Electrochemical impedance spectroscopy experiments have shown that the apparent diffusion coefficient for nanotubes with template was approximately 1×10−9 cm2 s−1. Nanotubes with polyaniline presented an apparent diffusion coefficient at least one order in magnitude higher than the parent material “with template”, comparable with other vanadium oxide described in the literature, revealing a promising material for utilization as cathode for ion-Li batteries.
Objectives To investigate the effect of a yearlong multicomponent rehabilitation program on the level of physical activity (PA) and the maintenance of the level of PA over 1-year follow-up among older people recovering from a recent hip fracture. Design Secondary analysis of a randomized, controlled, parallel-group trial. Setting Home-based rehabilitation; measurements in university laboratory. Participants Community-dwelling people (N=81) aged ≥60 years recovering from a hip fracture. Participants were randomly assigned to an intervention (n=40) or a control (n=41) group, on average, 42±23 days after discharge from the hospital. Intervention A yearlong intervention included evaluation and modification of environmental hazards, guidance for safe walking, nonpharmacologic pain management, a progressive home exercise program, PA counseling, and standard care. Main Outcome Measures The outcome was the level of PA, which was assessed with the questionnaire (a modified Grimby scale) at baseline, and 3, 6, 12, and 24 months after baseline. Three PA categories were defined: inactivity, light PA, and moderate to heavy PA. Physical function was assessed using the Short Physical Performance Battery (SPPB) at baseline. The effects of the intervention were analyzed with generalized estimating equations. Results In the intervention group, a significant increase was observed in the level of PA after the intervention (interaction P=.005) and after 1-year follow-up (P=.021) compared with the standard care only. The benefit was particularly evident among the participants with a baseline SPPB score of ≥7 (interaction P<.001). Conclusions The 12-month individualized multicomponent rehabilitation program increased PA among older patients with hip fracture. The increase was found to be maintained at the 1-year follow-up.