batterydata/paper-abstracts huggingface dataset:
Layered Li1+x (Ni0.3Co0.4Mn0.3)O2−δ (x =0, 0.03 and 0.06) materials were synthesized through the different calcination times using the spray-dried precursor with the molar ratio of Li/Me=1.25 (Me=transition metals). The physical and electrochemical properties of the lithium excess and the stoichiometric materials were examined using XRD, AAS, BET and galvanostatic electrochemical method. As results, the lithium excess Li1.06(Ni0.3Co0.4Mn0.3)O2−δ could show better electrochemical properties, such as discharge capacity, capacity retention and C rate ability, than those of the stoichiometric Li1.00(Ni0.3Co0.4Mn0.3)O2−δ . In this paper, the effect of excess lithium on the electrochemical properties of Li1+x (Ni0.3Co0.4Mn0.3)O2−δ materials will be discussed based on the experimental results of ex situ X-ray diffraction, transmission electron microscopy (TEM) and galvanostatic intermittent titration technique (GITT)
DC testing of electrochemical capacitors has been reviewed with emphasis on the test procedures used by the USABC, IEC, and the University of California-Davis (USA). Differences in the test procedures are identified and the effect of the differences on the inferred characteristics of various carbon/carbon and hybrid (pseudo-capacitive) electrochemical devices evaluated from test data. The effect of the test procedures is greater for hybrid devices than carbon/carbon capacitors. It was found that the differences in the test procedures have a minor effect on capacitance, but larger effects on resistance and energy density. The pulse power capability of devices is calculated from the rated voltage of the device and its measured resistance. The inferred power capability of a device based on the matched impedance value (V 2/4R) is nearly a factor of ten higher than that corresponding to an efficiency of 95% as required in the USABC and IEC test procedures.
There have been few systematic reports of vision-related activity limitations of people with retinitis pigmentosa (RP). We report a merging of data from the National Eye Institute Visual Function Questionnaire (NEI-VFQ) obtained in five previous studies. We asked whether the Vision Function Scale (VFS; Pesudovs et al., 2010) which was developed for cataract patients would apply in this new population (condition).
Executive cognitive functioning develops late during adolescence, being considered as basis for early mathematical learning. Our work studies the possible relationship between aptitude in some executive functions with respect to mathematical academic performance and the age of the students, through neuropsychological tests. The quantitative results showed a direct relationship between age and work memory recall, alternating attention, cognitive flexibility and processing speed, being more discrete about mathematical performance. The conclusion based on our results calls for the inclusion of qualitative interpretation of the data, by considering both, intra-subject variables, as those linked to the educational context.
Infection following hip arthroplasties can present a diagnostic challenge. No test is 100% sensitive and 100% specific; this prospective study was undertaken to evaluate the utility of FDG-PET imaging for diagnosing infected joint replacements. 24 hip joint replacements were studied prospectively and we have complete diagnoses with clinical signs and symptoms, laboratory tests, radiography, joint aspiration, radionuclide imaging including FDG-PET, and histopathologic examination. 11 of 24 prostheses were infected. The sensitivity and specificity of PET for detecting infection associated with prostheses were 64.3% and 64.7% respectively, in our study. FDG imaging is not useful in patients with suspected prosthetic infection as a screening test.
Understanding the electrical double layer (EDL) structure at the solid/liquid interface is critical towards realizing the full potential of electrochemical applications using ionic liquids. In this work, the out-of-plane and in-plane EDL structures of PYR14-TFSI on graphite (HOPG) have been studied by in-situ electrochemical atomic force microscopy (AFM) and molecular dynamics (MD) simulation. AFM results revealed that the first adsorbed ion layer on HOPG consists of both disordered and ordered lateral domains. It has been found that the neighboring molecules in the x-y plane form intricate ordered lateral structures on length scale of hundreds of nanometers, and the out-of-plane EDL structure is independent of the in-plane structure. MD simulations under zero polarization showed that in the first adsorbed layer, cations have one preferred orientation while anions have two preferred orientations in relation to the HOPG surface, which might be the origin of the complex lateral ordering. When polarizing the surface, a hysteretic order-disorder transition of the lateral ordering in the first adsorbed layer can be observed by in-situ AFM, and the ordered domains disappear for high positive or negative voltages. Comparison with bias-dependent MD reveals that the existence of a bimodal anion distribution in the first absorbed layer can be linked to the observed transitions giving new insights into the origin of the structural domains, which can help understand unusual charge and discharge kinetics observed in similar systems.
Carbon nanotube (CNT) and TiO2 nanofibre composite films are prepared and used as anode materials for lithium ion batteries (LIBs) without the use of binders and conventional copper current collector. The preliminary experimental results from X-ray diffraction, scanning electron microscopy and transmission electron microscopy suggest that the TiO2 nanofibres were well-dispersed and interwoven by the CNTs, forming freestanding, bendable and light weighted composite. In comparison with TiO2 nanofibre based LIBs, the CNTs could significantly improve the battery performance due to their high conductivity property and 3D network morphology. In both 1–3V and 0.01–3V testing voltage ranges, the as-prepared composites show excellent reversible capacity and capacity retention. The superior lithium storage capacity of the CNT/TiO2 composite was mainly attributed to dual functions of the CNTs – the CNTs not only provide conductive networks to assist the electron transfer but also facilitate lithium ion diffusion between the electrolyte and the TiO2 active materials by preventing agglomeration of TiO2 nanofibres. This work demonstrates that the CNT–TiO2 composite film could be one type of potential electrode material for large-scale LIB applications.
The Li metal anode is an ideal candidate for next-generation batteries due to its ultra-high specific capacity (3860 mAh g −1) and low electrochemical potential (−3.040 V vs. standard hydrogen electrode). However, the large volume fluctuations, side reactions, and dendrite growth are serious problems that need to be solved before Li metal batteries (LMBs) can be commercialized. Herein, we develop a lithiophilic 3D Cu nanowire (3D CuNW) host that can enable molten Li infusion into the structure. Interestingly, the 3D host undergoes a structural transformation upon contact with molten Li and forms Cu-Li alloy crystallites on the surface, leading to the development of an ultra-high performance Li metal anode (3D Li@CuLi). The symmetrical cell performance of the 3D Li@CuLi electrode is found to be among the best reported for carbonate-based electrolytes and can achieve greater than 200 cycles at an ultra-high current density of 10 mA cm −2. Furthermore, full cells coupled with LiFePO4 cathodes show excellent cycling stability at a C-rate of 2 C for over 400 cycles with negligible capacity fade. This work provides a scalable and highly effective approach towards the fabrication of high performance 3D hosts with pre-stored Li metal for next-generation battery systems.
PbSbO2Cl@C nanocomposite is synthesized via a simple one-step hydrothermal route and tested as a lithium storage material. The as-prepared PbSbO2Cl@C nanocomposite presents a core–shell structure composing of PbSbO2Cl nanoparticles (20–200nm) as inner core and amorphous carbon coating layer as outer shell. The core–shell structure of PbSbO2Cl@C can restrict the structural breakdown of nanocomposite with carbon coating layer on the surface, and avoid the pulverization and aggregation of PbSbO2Cl nanoparticles during repeated lithiation–delithiation process. Moreover, the induction of carbon layer can also improve the electronic conductivity and reduce the charge transfer resistance of PbSbO2Cl. As a result, PbSbO2Cl@C nanocomposite exhibits improved electrochemical performances compared to pristine PbSbO2Cl.
In this work, we investigate the effect of polyvinylpyrrolidone (PVP) on the morphology and the interfacial properties of lead dioxide (PbO2). The electrodeposition of lead dioxide was achieved in the presence of PVP on Pt and Ti substrates under constant current density from solutions containing Pb(NO3)2 and NaF in HClO4. Scanning electron microscopy (SEM) showed that the morphology and particle size of PbO2 are strongly affected by the concentrations of Pb(NO3)2, PVP and HClO4. It seemed that PVP can control both the morphology and particle size of lead dioxide and increases the overpotential for oxygen evolution during the electrodeposition of lead dioxide. The resulting lead dioxide was composed of nano-metric globular particles aligned in rice shaped structure with diameter in the range of 30–50nm. It was suggested that the growth of PbO2 crystals is affected by the aqueous network of self-assembled surfactant formed on the electrode surface during the electrodeposition process. The electrochemical impedance spectroscopy (EIS) was used to investigate the interfacial behavior of deposited lead dioxide in 0.5M H2SO4 solution. The EIS results revealed a typically porous electrode behavior consisted of a straight line, at high frequency region, turning to a potential dependent semicircle, at low frequency region, the diameter of which being decreased with increasing potential increments. The X-ray diffraction (XRD) patterns show that samples were composed of β-PbO2.
Porous Li4Ti5O12 nanoclusters with high surface area are synthesized by a facile solution-based method followed by low-temperature calcination. The Li4Ti5O12 nanoclusters present the key characteristics needed to serve as high-performance negative electrodes for lithium ion batteries, including nano-sized dimension of the Li4Ti5O12 clusters (50–100 nm) for short ion and electron transfer path, and high surface area (142 m2 g−1) with mesoporosity (pore diameter 2–6 nm) for easy access to the electrolyte and efficient ion transport. Based on these characteristics, the Li4Ti5O12 electrode delivers an initial capacity of 173 mAh g−1 at the rate of 0.5 C, comparable to its theoretical capacity. Excellent cycling stability at high rates is achieved in the Li4Ti5O12 electrode, offering potential to serve as a negative electrode material for high rate lithium ion battery applications.
In the last years, energy storage systems are increasingly involved in applications in which they are required to deliver or adsorb significant charging or discharging currents in short intervals of time, typically a few seconds. Thanks to their high specific power, supercapacitors may represent one of the most promising technologies for this kind of applications. However, one of the main concerns regarding their operation is the accurate estimation of their state of charge; the most common technique, based on ampere-hour counting, typically requires some correction mechanisms, since it implies a significant loss of accuracy over time, due to the accumulation of measuring errors. In the present paper, a novel algorithm to assess the state of charge of supercapacitors is described and implemented. The algorithm is based on the evaluation of the parameters of an equivalent electric circuit of the supercapacitor, and on the consequent use of a Luenberger-style technique for the runtime evaluation of its state of charge, based on the measure of current and voltage at supercapacitor's terminals. The algorithm estimates the cell open circuit voltage while the current is highly variable, as typical in power-oriented applications, hence the corresponding state of charge.
To explore the effectiveness of preoperative rehabilitation programmes (PreHab) on postoperative physical and psychological outcomes following anterior cruciate ligament reconstruction (ACLR).
Although lithium–sulfur batteries are one of the most promising energy storage devices with broad applications, they are hampered by the poor cycling problems associated with both the sulfur cathode and the lithium-metal anode. Herein, we develop a newly configured lithiated silicon–sulfur battery by using a honeycomb-like sulfur copolymer on 3D graphene (3D cpS-G) as the cathode and a 3D lithiated Si-G network as the anode. In the case of 3D cpS-G, the honeycomb-like sulfur copolymer are uniformly distributed on three-dimensional graphene networks. Such a unique cathode not only facilitates the fast diffusions of electron and lithium, but can also efficiently inhibit the dissolution of polysulfides and accommodate the large volume change of the sulfur copolymer during cycling processes. When assembled as half cells, the 3D cpS-G exhibits excellent electrochemical performance. More attractive is that when coupled with the 3D lithiated Si-G anode, the full Si–S cell exhibits superior electrochemical performances in term of a high reversible capacity of 620 mA h g−1, an ultrahigh energy density of 1147 W h kg−1 (based on the total mass of the cathode and the anode), good high-rate capability and excellent cycle performance over 500 cycles (0.028% capacity loss per cycle).
The N2O-mediated oxidative dehydrogenation of propane over iron-containing MFI zeolites was studied by in situ diffuse reflectance Fourier transform infrared spectroscopy, complemented by analyses in a tapered element oscillating microbalance coupled with gas chromatography and characterization by X-ray diffraction, transmission electron microscopy, and N2 adsorption. Samples with different iron speciation and acidic properties, induced by the preparation method (ion-exchange and steam activation) and the framework composition (Fe–Al–Si, Fe–Ga–Si, and Fe–Ge–Si) were analyzed. Real-time monitoring of the reaction under operando conditions allowed us to gain insight into the mechanism and kinetics of deactivation and coke formation, as well as zeolite regeneration in air. Deactivation of iron zeolites in the oxidative dehydrogenation of propane is caused by coke deposition on active extra-framework iron species. The mechanism of coke formation and the nature of the deposits were similar over the samples, independent of the catalytic performance and deactivation pattern. Regeneration in air led to the disappearance of coke-related bands and the practically complete recovery of the original porosity, while the zeolite crystallinity remained intact. The initial propylene yield over the fresh and regenerated Fe–Ga–Si zeolites was the same, but the latter sample exhibited faster deactivation. This is attributed to a change of iron constitution in the first reaction–regeneration cycle. The alteration of the local environment of the iron species was indirectly concluded from the appearance of a band associated with Lewis centers in the infrared spectra of the regenerated zeolite. In support of this, TEM studies demonstrated an extensive degree of iron clustering as FeO x nanoparticles in the regenerated catalyst compared with the fresh and coked catalysts.
In this work, we studied the changes in volume of an electroactive polymer as [Os(bipy)2 (PVP)10Cl]2+. The dependence of the polymer volume on the solution pH and applied potential was measured. The morphology of [Os(bipy)2 (PVP)10Cl]2+, deposited onto monocrystalline Si substrates, both by drop coating and by spin coating was studied by AFM. Drop-coated films show a globular structure on top of a thin and homogeneous film while spin-coated films are even and homogeneous. The volume changes with the pH of the external solution were measured following the changes in the globules size of drop-coated films. Also, the thickness dependence of spin-coated films on pH was measured by AFM. Both the size of the globules and the thickness of the films increase as the pH of the external solution decreases. The possible reasons for this increase are discussed. The volume change following the oxidation of a drop-coated polymer was estimated from the projected area obtained by optical microscopy with image capture. The images show an increase in the projected area as the film is progressively oxidized. The possible reasons for this increase in volume are discussed.
LABAT '02 will be held at the Grand Hotel Varna, in the beautiful Black Sea resort of St. Constantine near Varna. The meeting will once again provide an excellent forum for academic scientists and battery researchers from all over the world to meet and discuss fundamental problems related to the lead–acid battery system. Battery engineers and designers will discuss the latest achievements and future trends in lead–acid battery technology and manufacturing practices. Suppliers of battery making equipment and materials will have the opportunity to exhibit their products and services, and to conduct marketing research and negotiations with battery manufacturers and users. Address for further information Professor D. Pavlov Central Laboratory of Electrochemical Power Sources, Acad. G. Bonchev Street, Block 10, Sofia 1113, Bulgaria Tel: +359-2-718-651; fax: +359-2-731-552; e-mail: dpavlov@mbox.cit.bg Closing date for initial submission of papers and pre-registration: 15 November 2001 http://www.labatscience.com or http://www.acad.bg/labat02
Verbal and non-verbal learning were investigated in 21 8–11-year-old dyslexic children and chronological-age controls, and in 21 7–9-year-old reading-age controls. Tasks involved the paired associate learning of words, nonwords, or symbols with pictures. Both learning and retention of associations were examined. Results indicated that dyslexic children had difficulty with verbal learning of both words and nonwords. In addition, analysis of the errors made during nonword learning showed that both phonological errors and general learning errors were distributed similarly for the reading groups. This suggests that nonword learning in dyslexics is slower, but not qualitatively different from normal readers. Furthermore, no differences were found between the dyslexics and age-matched normal readers on non-verbal learning. Long-term retention of the learned visual–verbal associations (both words and nonwords) was not impaired in dyslexic children as compared to normal readers. Finally, phonological awareness ability was assessed. Dyslexics performed worse than age-matched normal readers, but similar to reading-age controls.
This paper describes the synthesis and electrochemical characterization of Sn70Ge30@carbon core–shell nanoparticles prepared by vacuum annealing of the alkyl-capped Sn70Ge30 nanoparticles obtained from the reaction of SnCl4 and GeCl4 with sodium naphthalide in ethylene glycol dimethyl ether (glyme) and RLi (R=butyl, ethyl, methyl). The Sn70Ge30@carbon core–shell nanoparticles have different core sizes and shell thicknesses depending on the alkyl terminator. The annealed nanoparticles that terminate with butyl and ethyl groups have core sizes of ∼14 and ∼17nm with carbon shell thicknesses of ∼16 and ∼8nm, respectively. On the other hand, annealed nanoparticles that terminate with methyl groups have core sizes of 40nm with a very thin carbon shell without uniform coverage of the core. Electrochemical characterization shows that nanoparticles prepared using butyl terminators have the highest capacity retention out to 40 cycles (95%) and a first charge capacity of 1040mAh/g. On the other hand, ethyl- and methyl-capped nanoparticles show 82 and 64% capacity retention after 40 cycles.
A simulation model of a two mode power-split hybrid electric vehicle (HEV) is proposed in this paper for the purpose of HEV dynamics analysis and control system design. The bond graph methodology is used to model dominant dynamic effects of the mechanical part of the HEV transmission. Simple quasi-static battery model, the environment model, the tire and the power losses model of a vehicle are included, as well. A low-level electric generator speed control loop is designed, which includes a PI controller tuned according to the symmetrical optimum tuning procedure. Finally, off-line optimization by conjugate gradient-based BPTT-like optimal control algorithm, which is based on the presented mathematical model, is also given in the paper.
Background and aims Besides motor function the cerebellum subserves frontal lobe functions. Thus, we investigated executive functions in pediatric posterior fossa tumor survivors. Methods We tested information processing, aspects of attention, planning and intelligence in 42 pediatric posterior fossa tumor survivors (mean age 14.63 yrs, SD 5.03). Seventeen low-grade tumor patients (LGCT) were treated with surgery only and 25 high-grade tumors patients (HGCT) received postsurgical adjuvant treatment. We evaluated simple reaction time, executive functioning, i.e. visuospatial memory, inhibition, and mental flexibility using the Amsterdam Neuropsychological Tasks program, whereas forward thinking was assessed with the Tower of London-test. Intelligence was determined using the Wechsler Intelligence Scale. Ataxia was assessed with the International Cooperative Ataxia Rating Scale. Results About one third of each patient group showed forward thinking scores below one standard deviation of the norm. Impaired forward thinking correlated significantly with degree of ataxia (r = −0.39, p = 0.03) but not with fluid intelligence. Both patient groups exhibited executive function deficits in accuracy and reaction speed in more difficult tasks involving information speed and attention flexibility. Still, HGCT patients were significantly slower and committed more errors. Working memory was inferior in HGCT patients. Conclusion Pediatric cerebellar tumor survivors with different disease and treatment related brain damage exhibit similar patterns of impairment in executive functioning, concerning forward thinking, inhibition and mental flexibility. The deficits are larger in high-grade tumor patients. The pattern of function loss seen in both groups is most probably due to comparable lesions to cerebro-cerebellar circuits that are known to modulate critical executive functions.
Electro-chemical impedance spectroscopy is widely used to analyze electro-chemical systems. Most attention is paid to the double-layer capacitance and the charge-transfer resistance as they describe the electro-chemical process on the surface of the electrode. Both values can provide specific information about aging mechanisms, which diminish the surface area. This is of interest when capacity tests are restricted to determine the aging. For lead-acid batteries, for example, this is the case in applications like micro-hybrid vehicles or uninterruptible power supply systems. However, the interpretation of impedance spectra of lead-acid batteries necessitates proper measurements, elaborated verification of measurement validity, and a sufficient model of electro-chemical processes. In this work, impedance spectra, recorded on lead-acid test cells, are processed to identify the ohmic resistance, the double-layer capacitance, and the parameters of the charge-transfer reaction of the negative electrode. This electrode suffers from sulfation, a common aging mechanism in current applications. The aim of the paper is to define a correct processing of impedance spectra for lead-acid batteries, and to depict challenges. Furthermore, possible equivalent electrical circuit models for the negative electrode are evaluated regarding their dependencies on state of charge and current rate. Many of these aspects can be transferred to other electro-chemical systems.