batterydata/paper-abstracts huggingface dataset:
Few studies have directly compared the clinical and anatomical characteristics of patients with progressive aphasia to those of patients with aphasia caused by stroke. In the current study we examined fluent forms of aphasia in these two groups, specifically semantic dementia (SD) and persisting Wernicke’s aphasia (WA) due to stroke. We compared 10 patients with SD to 10 age- and education-matched patients with WA in three language domains: language comprehension (single words and sentences), spontaneous speech and visual semantics. Neuroanatomical involvement was analyzed using disease-specific image analysis techniques: voxel-based morphometry (VBM) for patients with SD and overlays of lesion digitized lesion reconstructions in patients with WA. Patients with SD and WA were both impaired on tasks that involved visual semantics, but patients with SD were less impaired in spontaneous speech and sentence comprehension. The anatomical findings showed that different regions were most affected in the two disorders: the left anterior temporal lobe in SD and the left posterior middle temporal gyrus in chronic WA. This study highlights that the two syndromes classically associated with language comprehension deficits in aphasia due to stroke and neurodegenerative disease are clinically distinct, most likely due to distinct distributions of damage in the temporal lobe.
We have demonstrated, for the first time, efficient 120Hz filtering by an electric double layer capacitor (EDLC). The key to this ultra-high-power performance is electrodes made from vertically oriented graphene nanosheets grown directly on metal current collectors. This design minimized both electronic and ionic resistance and produced capacitors having RC time-constants of less than 200μs. Significantly, graphene nanosheets have a preponderance of exposed edge planes that greatly increase stored charge over designs relying on basal plane surfaces. Collectively these factors make vertically oriented graphene nanosheet electrodes ideally suited for producing high-frequency EDLCs. Capacitors constructed with these electrodes are predicted to be significantly smaller than aluminum electrolyte capacitors that they could functionally replace plus be manufactured using standard semiconductor process equipment, creating interesting commercial opportunities.
The hard carbon is attractive for the Li ion secondary battery because of its higher capacity than the theoretical value of 372Ahkg−1 based on the composition of stage 1 Li-intercalated graphite, LiC6. However, the structure of hard carbon as an anode has not been optimized and the reaction mechanism also has not been clarified in detail. In the present study, the structure of hard carbon derived from oxygen-containing coal tar pitch was investigated by X-ray diffraction, small angle scattering and density measurement, and the relationship between the structure of hard carbon and its anode performance was discussed.
Efficient electrocatalyst for oxygen reduction reaction (ORR) is an essential component for stable operation of various sustainable energy conversion and storage systems such as fuel cells and metal-air batteries. Herein, we report a facile preparation of meso/macroporous Co and N co-doped carbon nanofibers (Co-Nx@CNFs) as a high performance and cost-effective electrocatalyst toward ORR. Co-Nx@CNFs are simply obtained from electrospinning of Co precursor and bicomponent polymers (PVP/PAN) followed by temperature controlled carbonization and further activation step. The prepared Co-Nx@CNF catalyst carbonized at 700 °C (Co-Nx@CNF700) shows outstanding ORR performance, i.e., a low onset potential (0.941 V) and half wave potential (0.814 V) with almost four-electron transfer pathways ( n = 3.9). In addition, Co-Nx@CNF700 exhibits a superior methanol tolerance and higher stability (>70 h) in Zn-air battery in comparison with Pt/C catalyst (∼30 h). The outstanding performance of Co-Nx@CNF700 catalysts is attributed to i) enlarged surface area with bimodal porosity achieved by leaching of inactive species, ii) increase of exposed ORR active Co-Nx moieties and graphitic edge sites, and iii) enhanced electrical conductivity and corrosion resistance due to the existence of numerous graphitic flakes in carbon matrix.
Electric mobility is regarded as an important option for reducing environmental impacts of transport. State incentives and planning efforts for the mass deployment of a public charging infrastructure (CI) are in hand in many countries; in particular, public CIs based on the Level 3 DC fast charge are most likely to become commercially viable in the short to medium term, as the drivers are more likely to view the operation as traditional refuelling. The aim of this work is to develop a procedure for the evaluation of the level of service of a configuration of electric fast charging stations (CI scenario), located in a selected urban area of the city of Rome. By varying the configuration of the stations in the area, and taking into account a charge demand inferred from real-world traffic data, we are able to make comparative analyses among different CI scenarios, and to determine the best one in terms of average and maximum waiting time to recharge (demand-side analysis). The steps considered included: creation of realistic CI scenarios based on lists of existing car parks and petrol stations; estimation of the potential battery electrical vehicle (BEV) users in the selected urban area using a Big Data analysis procedure; development of a fuzzy model to assign BEV users to stations with a criterion of convenience; use of a simulation procedure of all the charge events, in order to obtain a time profile of customer crowding at stations.
Supercapacitors, known as ultracapacitors, have been supposed to be one of the most promising candidates to meet requirements of human’s sustainable development, due to their advantages such as high capacitance and rate capability, long cycle life and low processing cost. Electrode materials play a decisive role on performance of supercapacitors, thus researches on electrode materials are critical to supercapacitors. Conducting polymer (CP) -based materials exhibit high potential in supercapacitors because of their unique advantages including good conductivity, flexibility, relatively cheap, easy of synthesis and so on. This review summarizes recent research progress of CPs (including polypyrrole (PPy), polyaniline (PANi), and polythiophene (PTh)), the CP-based binary composite, and the CP-based ternary composite electrode for supercapacitors. In the end, we give a brief outline of development directions of CP-based supercapacitors in the future.
A loose whisker-like Co(OH)2 was synthesized by means of polyethylene glycol 4000 as soft template under ultrasonic condition, and investigated as an active electrode material for electrochemical capacitors. The composition and microstructure of the as-prepared Co(OH)2 were investigated by X-ray diffraction spectroscopy and transmission electron microscopy. The formation mechanism of the whisker-like Co(OH)2 was attentively proposed based on Fourier transform infrared spectroscopy analysis. Electrochemical studies revealed that the whisker-like Co(OH)2 delivered a specific capacitance of 325F/g at a current density of 20mA/cm2 (ca. 1.3A/g) and even 279F/g at 80mA/cm2 (ca. 5.3A/g) due to its special nanostructure, indicating its fast electrochemical response property. A capacitance attenuation of ca. 7% over 1000 cycles meant the good cyclic stability of the whisker-like Co(OH)2 for electrochemical capacitors application.
In situ thermal expansion and in situ X-ray powder diffraction (XRD) are used to investigate the dynamic process of the interaction between Ni and methane at high temperature. Thermal expansion results show that it takes 68 min for the Ni and yttrium-stabilized zirconia (Ni-YSZ) cermet at 650 °C to collapse, while it takes only 14 min at 800 °C when exposed to methane. The crystal structure change of Ni, when it interacts with methane at high temperature, is directly observed by in situ XRD characterization. The results of scanning electron microscopy and transmission electron microscopy show a large number of carbon fibers on Ni particles in methane at 650 °C, whereas a considerable amount of encapsulating carbon and few carbon fibers are noted at 800 °C. On the basis of the experimental results, the deactivation mechanisms of Ni-YSZ cermet in methane at 650 °C and 800 °C are elucidated, respectively.
Owing to scientific importance associated with highly reactive surfaces, the research concerning inorganic single crystals with a large percentage of exposed high-index facets has attracted much attention. In current research, α-Fe2O3 nanocubes exposed with (012) active facet was firstly synthesized via a hydrothermal method. And then a freeze-drying approach was utilized to construct nanostructured Fe2O3/graphene composite. The as-obtained composite exhibited s higher BET surface area than that of bare α-Fe2O3 nanocubes. When evaluated for lithium storage properties, the Fe2O3/graphene rendered remarkable electrochemical cycle stability and high rate performance. At the rate of 300 mA g−1, a high reversible discharge capacity of 1136 mAh g−1 was obtained up to 200 cycles. In addition, the excellent rate performance was also achieved. Excellent electrochemical properties are probably ascribed to the synergistic effect of α-Fe2O3 nanocubes and graphene sheets, as a result of smart structure design via a freeze-drying route. This strategy with merits of rational construction and scalable production could establish new perspective for diverse composites towards commercial application.
Our aim was to explore the interplay between human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections in the expression of cognitive disorders.
Arrays of individual lithium nanobatteries were constructed using alumina membranes having pores 200nm in diameters. These pores served as the “jackets” to hold a PEO-lithium triflate electrolyte. The pores were then capped with a cathode material consisting of an ambigel of V2O5 making arrays of individual nanobatteries. Cyclic voltammetry data indicated that a nanoelectrode array model could describe these arrays of cathodes. However, individual nanobatteries were further characterized by charge/discharge tests using atomic force microscopy cantilever tips to make electrical contact with the 200nm cathodes of the nanobatteries. Average volumetric capacities of 45μAhcm−2 μm−1 were recorded for these battery systems, demonstrating that these small lithium batteries could function as viable, miniaturized power sources for future nanodevices.
A novel nanohybrid material composed of vanadium pentoxide nanofibres (VNFs) and exfoliated graphene were prepared by in-situ growth of VNFs onto graphene nanosheets, and explicated as electrode material for supercapacitor applications. The existence of non-covalent interactions between VNFs and graphene surfaces was confirmed by Raman and Fourier transform infrared (FTIR) spectroscopes. Morphological analysis of the nanohybrid revealed that the VNF layer uniformly grown on the graphene surfaces, producing high specific surface area and good electronic or ionic conducing path. High crystalline structure with small d-spacing of the VNFs on graphene was observed in X-ray diffraction (XRD) analysis. Compared to pristine VNF, the VNF/graphene nanohybrid exhibited higher specific capacitance of 218 F g−1 at current density of 1 A g−1, higher energy density of 22 Wh kg−1 and power density of 3594 W kg−1. Asymmetric supercapacitor devices were prepared using the Spectracarb 2225 activated carbon cloth and VNF/graphene nanohybrid as positive and negative electrode, respectively. The asymmetric device exhibited capacitance of 279 F g−1 at 1 A g−1, energy density of 37.2 Wh kg−1 and power density of 3743 W kg−1, which are comparable and or superior to reported asymmetric devices consisting of carbon material and metal oxide as electrode components.
Diethyl phenylphosphonite (DEPP) is used as a novel electrolyte additive to improve the cyclability of spinel LiMn2O4 upon cycling at elevated temperature (55 °C). The charge/discharge cycling stability results indicate that capacity retention of Li/LiMn2O4 cell is significantly improved from 40 to 78% at a rate of 1C (1C = 120 mAh g−1) when 1.0 wt% DEPP is added to the baseline electrolyte (1.0 M LiPF6 in EC/EMC/DEC (3:5:2, vol.%)) after 450 cycles at 55 °C. This improvement can be attributed to the preferential oxidation of DEPP to that of the baseline electrolyte and the subsequent formation of a protective film on the cathode surface. This passivation film suppresses detrimental electrolyte decomposition and in turn protects LiMn2O4 from further decomposition. Molecular energy level calculations, linear sweep voltammetry, and cyclic voltammetry results confirm that DEPP is oxidized on the cathode surface prior to the oxidation of carbonate solvents. Electrochemical impedance spectroscopy illustrates that the the cathode interfacial film generated from DEPP oxidation is more stable and robust than that of the surface film yielded from the baseline electrolyte’s decomposition. Ex situ surface-characterization results further support the claim that DEPP incorporation in the electrolyte suppresses the electrolyte oxidation at elevated temperature and the decomposition of LiMn2O4 cathode material as well.
Bhatt T, Espy D, Yang F, Pai Y-C. Dynamic gait stability, clinical correlates, and prognosis of falls among community-dwelling older adults. Objective To establish an accurate measure for prognostic assessment of fall risk in community-dwelling older adults, this study examined the prediction accuracy of a dynamic gait stability measure and common clinical tests for slip-related falls among these adults. Design Participants were tested for their fall-risk likelihood on a slip-test. Setting Biomechanics research laboratory. Participants Community-dwelling older adults (N=119; ≥65y). Interventions Not applicable. Main Outcome Measures Participants performed a battery of clinical tests, including Berg Balance Scale, Timed Up & Go (TUG) test, static posturography, isometric muscle strength, and bone density. They were then exposed to an unannounced slip during gait. The dynamic stability during unperturbed gait was measured based on the center of mass position and velocity relative to the limits of stability against backward falling. Accuracy of each measure was examined for prediction of slip outcome (fall or recovery). Results On the slip, 59 participants fell, 56 recovered their balance, and 4 were harness-assisted. Dynamic stability predicted fall outcome with 69% accuracy. Except for TUG and bone density, no other measure could differentiate fallers from nonfallers; TUG predicted 56% of fall outcomes. Conclusions Reproduction of actual falls provides a new benchmark for evaluating the prognostic power of different performance-based assessment tools. The TUG was able to better predict fall outcome than other clinical measures; however, the new dynamic gait stability measure was more sensitive than TUG in its prediction of falls. Ultrasound bone scan could be used to screen older adults for fall risk.
Three different synthesis techniques (hydrothermal synthesis, modified Pechini synthesis and Pechini synthesis) were successfully used for preparation of Li2FeSiO4 samples. The obtained samples possess some differences in the morphology and in the particle size, as well as in the presence of in situ formed carbon. The best electrochemical performance has been obtained with the smallest particles embedded into carbon matrix. Such a Li2FeSiO4/C composite contains the highest amounts of impurities (Fe2O3, SiO2 and Li2SiO3) and only 68.8at.% of iron is in the form of FeII as detected by Mössbauer spectroscopy, respectively. Despite the highest amount of impurities, the sample shows the highest reversible capacity (approximately 100mAhg−1 based on whole silicate-derived material). With the proper structuring of Li2FeSiO4/C composites, utilisation of large part of capacity is also possible at current densities corresponding to C/5 and C/2 cycling rate. A lower amount of impurities was found in the samples that do not contain any in situ carbon after synthesis. Among them, the highest purity is possessed by the sample prepared at 900°C, as determined using Mössbauer spectroscopy. The results obtained by Mössbauer spectroscopy and XRD analysis indicate on the differences in the crystal structure between the thermally treated samples and the sample prepared by hydrothermal synthesis.
Objective To examine the relationship of cognitive performance to exposure to insulin (INS) and thiazolidinediones (TZD) in the ACCORD-MIND cohort. Methods Participants (55–80years) with type 2 diabetes (T2D), hemoglobin A1c (HbA1c) >7.5% (>58mmol/mol), and a high risk of cardiovascular events were randomly assigned to receive intensive control targeting HbA1c to <6.0% (42mmol/mol) or a standard strategy targeting HbA1c to 7.0%–7.9% (53–63mmol/mol). The Digit Symbol Substitution Test (DSST) was assessed at baseline and at 20 and 40months. Exposure to INS was calculated as average daily dose/kg of body weight; exposure to rosiglitazone (ROS) was calculated as days of ROS prescription in the intervals preceding the 20- and 40-month DSSTs. Results At baseline, INS use was associated with reduced DSST performance, but not after controlling for comorbidities and lab values. There was no relationship between use of a TZD and DSST performance on at baseline. ROS but not INS exposure was associated with greater decline in DSST performance over 40months in subjects randomized to the intensive but not the standard group. Conclusions Exposure to a TZD may increase cognitive decline in some patients with T2D. However, these results may be confounded by unexplained differences between participants.
Advanced composite electrodes containing multiple active components are often used in lithium-ion batteries for practical applications. The performance of such heterogeneous composite electrodes can in principle be enhanced by tailoring the concurrent reaction dynamics in multiple active components for promoting their collective beneficial effects. However, the potential of this design principle has remained uncharted to date. Here we develop a composite anode of Cu/Si/Ge nanowire arrays, where each nanowire consists of a core of Cu segments and a Si/Ge bilayer shell. This unique electrode architecture exhibited a markedly improved electrochemical performance over the reference Cu/Si systems, demonstrating a stable capacity retention (81% after 3000 cycles at 2C) and doubled specific capacity at a rate of 16C (1C = 2 A g−1). By using in situ transmission electron microscopy and electrochemical testing, we unravel a novel reaction mechanism of dynamic co-lithiation/co-delithiation in the active Si and Ge bilayer, which is shown to effectively alleviate the electrochemically induced mechanical degradation and thus greatly enhance the long-cycle stability of the electrode. Our findings offer insights into a rational design of high-performance lithium-ion batteries via exploiting the concurrent reaction dynamics in the multiple active components of composite electrodes.
Tin on a carbon paper (CP) was investigated by repeated galvanostatic cycles with time-limited charges to insert different amounts of lithium per Sn atom, and tin electrodeposited on copper was also investigated for comparison of the cyclic stability. The results demonstrated that, unlike Sn electrodeposited on Cu foil, Sn on CP can undergo several tens of lithiathion/delithiation cycles with Li/Sn atomic ratio ≤2 at high current density (0.70mAcm−2), thus confirming that carbon paper is a good current collector-substrate which is able to improve the cycling performance of tin by preserving the electric contact over cycling, in spite of the great volume changes during the lithium insertion/removal processes in tin.
1.5 Ah pouch cells based on Li(Ni0.5Mn0.3Co0.2)O2 cathodes and graphite anodes, both containing poly (vinylidene fluoride) (PVDF) binders, were systematically overcharged to 100, 120, 140, 160, 180, and 250% state of charge (SOC), at which point they vented. The cells were subsequently discharged to 0% SOC and disassembled under an inert atmosphere for characterization. A combination of X-ray photoelectron spectroscopy (XPS), scanning-electron microscopy (SEM), energy-dispersive spectroscopy (EDS), 6Li SSNMR, and X-ray diffraction (XRD) analysis of the NMC532 cathodes indicates the formation of a thin C- and O-rich cathode electrolyte interphase layer, progressive Li loss above 140% SOC, and retention of the bulk crystal structure at all states of charge.
Morphological defects contribute to chronic and acute failures of batteries. The development of these morphological defects entails the multiscale chemo-mechanical coupling associated with internal mechanical stress. The mechanical stress, caused by anisotropic structural, chemical and state of charge (SOC) heterogeneities, is released through crack formation, undermining the continuous diffusion pathways of electrons and ions and creating fresh surfaces for electrode–electrolyte side reactions. The understanding of chemomechanical interplay has remained at the descriptive level, thus, the quantification or model to fingerprint these processes is highly desired. Herein, we systematically investigate the mesoscale morphological defects within LiNi0.6Mn0.2Co0.2O2 secondary particles that have gone through fast-charging conditions. With the advanced synchrotron X-ray tomography, we nondestructively pierce the internal volume of secondary particles and quantify the morphological outcomes of the crack formation, such as porosity and internal surface area. We then develop a numerical model to predict the crack-induced diffusion deterrent of electrons and lithium ions. The mismatch between the local ionic and electronic conductivity can lead to highly heterogeneous SOC distribution in secondary particles, which exponentially deteriorates as the current density increases. Our incisive investigation of chemomechanical interplay and fast-charging can inform a knowledge base to accelerate the discovery of advanced materials that are resilient against chemomechanical failures.
Ether-based electrolytes offer many advantages compared to other electrolyte systems, but they are not stable in Li metal batteries when operating at high voltages. Here, the authors develop a concentrated ether electrolyte that enables long-term cycling stability of high-voltage Li metal batteries.
An indirect electrochemical determination method for ciprofloxacin (CIP) was developed based on the complexation of CIP with Cd2+. On graphene-modified electrode, Cd2+ showed a strong anodic stripping peak current response, which was efficiently prohibited in the presence of CIP. Thus, the anodic stripping peak current of Cd2+ was employed as the indicating signal for CIP determination, which was more sensitive than the direct electrochemical oxidation response of CIP. Some influence factors such as the modified volume of graphene, solution pH, accumulation time, complexation reaction time were systematically investigated. Under optimum conditions, the anodic stripping response of Cd2+ on the graphene-modified electrode was inversely proportional to CIP in the concentration range from 1.0×10−7 to 1.0×10−5 molL−1 with a detection limit (3S/N) of 5.9×10−8 molL−1. The method showed high selectivity, good reproducibility and was successfully applied to the determination of CIP in pharmaceutical formulation and human urine.