An all-solid-state lithium-ion battery with sulfide solid electrolyte is expected to be operated and fabricated under pressure to achieve high ionic conductivity. However, the varying mechanical ...properties of the constituent materials of composite electrodes generate a non-uniform stress distribution, which affects the ionic conductivity. Moreover, because of the presence of various active materials with different Young's moduli, the correlation between the Young's modulus of the active material and ion-conduction characteristics of a composite electrode is considered. In this study, to elucidate the effect of the Young's modulus of the active material on the ionic conductivity of a composite electrode, electrochemical impedance spectroscopy measurements and finite element method stress simulations based on X-ray computed tomography images are performed for model composite electrodes. The model composite electrodes are fabricated by mixing the solid electrolyte with zirconia or nylon in different volumetric fractions. The experimental results demonstrate that a composite electrode containing an active material with lower Young's modulus exhibits a higher ionic conductivity and lower saturation pressure. The finite element method stress simulation indicates that the change in the ion-conduction characteristics originates from the stress concentration induced by the active material's Young's modulus and volumetric fraction.
•EIS and X-ray CT measurements of composite electrodes are conducted.•The stress inside a composite electrode is analyzed using voxel-based FEM.•Stress concentrates in a material with higher Young's modulus.•The active material alters the saturation pressure of composite electrodes.•The ionic conduction is affected by the Young's modulus of the active materials.
High-pressure in situ three-dimensional structural measurements using X-ray computed tomography and electrochemical impedance spectroscopy measurement of a sulfide solid electrolyte are conducted to ...elucidate the influence of the nanoscale structure on its ionic conductivity. Computed tomography image-based three-dimensional numerical simulations are conducted to assess the ion-transportation phenomena. The results show that high-pressure in situ X-ray computed tomography can successfully enable visualization of crushing of the solid electrolyte particles and room-temperature pressure sintering. The ionic conductivity increases with an increase in applied pressure. The densified state achieved by room-temperature pressure sintering is maintained even after the applied pressure is decreased. The experimentally measured impedances are in close agreement with the computed tomography image-based numerical simulation results. This finding suggests that effects of internal stress on the contact resistance between sulfide solid electrolyte particles and their ionic conductivity are negligibly small. Furthermore, at small scale, ion-transportation characteristics can be estimated by the three-dimensional distribution of sulfide solid electrolyte and pores. The experiments and numerical simulations are conducted for various sulfide solid electrolytes, and these characteristics are found to be valid for all tested materials.
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•The compression characteristics of a sulfide solid electrolyte are discussed.•High pressure in situ X-ray CT and EIS measurements are conducted.•The numerical simulation results are in close agreement with experimental results.•The contact resistance between SE particles is negligibly small.•The ionic conductivity can be calculated from the distribution of SE and void.
The anode interface resistance and the critical current density of an all-solid-state lithium metal battery with oxide solid electrolyte needs improvement to obtain a suitable high-performance ...battery. In this study, surface processing of an oxide solid electrolyte by shot peening is achieved. The experimental results show that shot peening decreases the interface resistance to 1/24 of the interface resistance before this treatment and increases the critical current density by a factor of 7. This improvement in performance is comparable to that obtained by the conventional gold thin-film insertion method. Moreover, there is a synergistic effect between shot peening and gold thin-film insertion: lower interface resistances and higher critical current densities are obtained when using the two techniques together than when either method is used alone. The results of measurements of surface structural and mechanical characteristics suggest two reasons for the increase in the electrode performance with shot peening. One is that the surface roughness caused by shot peening increases the contact between the solid electrolyte and the lithium metal with inhomogeneous mechanical stress. The other is that shot peening increases the fracture toughness by applying a compressive residual stress, thus suppressing the growth of lithium dendrite.
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•Shot peening on SE increases the CCD and suppresses the interface resistance.•There is a synergistic effect between shot peening and gold thin-film insertion.•Roughness by shot peening increases the SE-Li contact.•The shot peening suppresses the crack generation on SE pellet.
Metastable <inline-formula> <tex-math notation="LaTeX">\alpha ' </tex-math></inline-formula>-Fe-N (12 at% N) and <inline-formula> <tex-math notation="LaTeX">\alpha ' </tex-math></inline-formula>-Fe-C ...(12 at% C) are unique materials with a magnetocrystalline constant <inline-formula> <tex-math notation="LaTeX">K_{1} </tex-math></inline-formula> of +<inline-formula> <tex-math notation="LaTeX">5\times10 </tex-math></inline-formula> 6 and <inline-formula> <tex-math notation="LaTeX">- 7\times10 </tex-math></inline-formula> 6 erg/cm 3 , respectively, according to measurements based on thin films. Therefore, co-addition <inline-formula> <tex-math notation="LaTeX">\alpha '' </tex-math></inline-formula>-Fe<inline-formula> <tex-math notation="LaTeX">_{16}X_{2} </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">X </tex-math></inline-formula> = N, C) particles are attractive as potential new soft magnetic materials because their magnetocrystalline constant can be varied by manipulating their N and C concentrations. However, introducing C interstitially into <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula>-Fe particles by the carbonization process using a C-containing gas such as CO gas is difficult because the equilibrium phase Fe 3 C is easily generated. Therefore, we investigated various reaction routes of nitridation and carbonization, along with various C-containing gases, to prepare co-addition <inline-formula> <tex-math notation="LaTeX">\alpha '' </tex-math></inline-formula>-Fe 16 (N, C) 2 particles. We obtained <inline-formula> <tex-math notation="LaTeX">\alpha '' </tex-math></inline-formula>-Fe 16 (N, C) 2 particles using a route in which <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula>-Fe was obtained by reduction of Fe 3 O 4 particles, followed by nitridation to <inline-formula> <tex-math notation="LaTeX">\alpha '' </tex-math></inline-formula>-Fe 16 N 2 and subsequent carbonization to <inline-formula> <tex-math notation="LaTeX">\alpha '' </tex-math></inline-formula>-Fe 16 (N, C) 2 . The amount of C particles after carbonization was measured to be 0.8 wt% (3.6 at%). This gas-solid reaction process based on the concept of using <inline-formula> <tex-math notation="LaTeX">\alpha '' </tex-math></inline-formula>-Fe 16 N 2 as a material with an expanded <inline-formula> <tex-math notation="LaTeX">\alpha </tex-math></inline-formula>-Fe lattice is a useful method for the co-addition of interstitial N and C.
Introduction One of the causes of epidemiological association of restless legs syndrome and cardiovascular disease is thought of as periodic limb movement during sleep associated with substantial ...elevation in heart rate (HR) and blood pressure. We describe a pacemaker-implanted patient with bradycardiac atrial fibrillation (AF), who was diagnosed with periodic limb movement disorder without marked HR elevation on polysomnographic examination, and progressed to CPA two months later. Materials and methods A 79-year old man came to our clinic because of daytime sleepiness. He had multiple histories, a cardiac pace-maker for bradycardiac AF and old myocardial infarction, hypertension, diabetes mellitus, coagulation factor deficiency, and renal failure. Results Polysomnography showed short sleep latency (1 min) with few respiratory events (AHI = 4.3) and few arousals (arousal index = 8.0). Sleep structure was poor with increased N1, decreased N2 and R. Periodic leg movement (PLM) during sleep index was 93.0. Heart rate increments for PLM without arousal and PLM with arousal are 0.585 ± 2.006 (0–36) and 1.029 ± 1.834 (0–10), respectively. Percentage of PLMs with HR elevation was only 27.8%. Conclusion This patient is a good example of critical PLM, with higher PLM index, decreased percentage of PLM associated HR elevation and decreased HR increments. Acknowledgements This was not an industry supported study. The author has indicated no financial conflict of interest.
•Modulated gravity spawn multiple transitions in convective structures.•Three-pronged (‘trident’) flow is discovered in the course of the transitions.•Snapshot POD analysis identified as many as 7 ...different flow structures.
Three-dimensional thermal convection in a cubic cavity heated from one wall and chilled from its opposite wall in the terrestrial-gravity and zero-gravity fields with and without a sinusoidal modulation is investigated numerically. The gravity and its modulation are parallel to the temperature gradient. An incompressible fluid with Prandtl number Pr = 7.1 (water) is considered and hence the Boussinesq approximation is used. The gravity-modulation parameters are a vibrational Rayleigh number Raη and a non-dimentional gravity-modulation frequency ω. Here the authors report a novel ‘trident’ flow structure in laminar and steady thermal convection, which consists of a point-symmetric pair of three-pronged flows, namely, three ascending streams and three descending streams in the cube. This flow structure is stable and persistent in the sense that it is observed in all three situations: a stationary cube under the terrestrial gravity, an oscillating cube under the terrestrial gravity, and an oscillating cube under zero gravity. A POD analysis confirmed this observation. Tested parameters are Rayleigh number Ra = 8.0 × 104 in the terrestrial-gravity field without the gravity modulation or Ra = 1.0 × 104; and the gravity modulation in the terrestrial-gravity field Raη = 1.0 × 105 and ω = 5.0 in the terrestrial-gravity field and Raη = 1.1 × 105 and ω = 5.0 in the zero-gravity field.
The strain tolerance of magnesium dioboride (MgB 2 ) wire should be enhanced at room temperature for fabricating MgB 2 coils by using the react and wind method. The irreversible external-compressive ...strain of MgB 2 filaments was measured by evaluating the critical current degradation of bent sample wires. From the results, MgB 2 filaments can accept -1.77% strain, and the pre-compressive strain should be -0.88% at room temperature to minimize its reversible bending radius. A stainless-steel reinforced 18-filament MgB 2 wire was fabricated and its strain tolerance was evaluated through bending and tensile tests at room temperature. The irreversible strain of this wire is 0.60%, and this wire seems to be suitable for the react and wind method. The filling factor of MgB 2 of this wire is 17%, so this wire has both suitable strain tolerance for the react and wind method and higher engineering current density.
Our research group has been researched for developing MgB2 superconducting energy apparatus in liquid hydrogen immersion cooling, such as superconducting generators. In this study, two-pole MgB2 ...race-track coil, which was a model for a few tens kVA superconducting generator field magnet, was designed and made. This coil consists of two pieces of a similar MgB2 race-track coil which has 529 turn with straight section of 150 mm, bending diameter in the end of section of 100 mm and thickness of 34 mm. We carried out excitation tests of the coil immersed in liquid hydrogen at the temperature of 21 K to 32 K, and the load line of the coil was obtained. The critical current under self-field was obtained for various temperatures. The normal zone propagation behavior of the coil at the quench was also investigated using several potential taps installed in the coil.
Exposure of the developing brain to propofol results in cognitive deficits. Recent data suggest that inhibition of neuronal apoptosis does not prevent cognitive defects, suggesting mechanisms other ...than neuronal apoptosis play a role in anaesthetic neurotoxicity. Proper neuronal growth during development is dependent upon growth cone morphology and axonal transport. Propofol modulates actin dynamics in developing neurones, causes RhoA-dependent depolymerisation of actin, and reduces dendritic spines and synapses. We hypothesised that RhoA inhibition prevents synaptic loss and subsequent cognitive deficits. The present study tested whether RhoA inhibition with the botulinum toxin C3 (TAT-C3) prevents propofol-induced synapse and neurite loss, and preserves cognitive function.
RhoA activation, growth cone morphology, and axonal transport were measured in neonatal rat neurones (5–7 days in vitro) exposed to propofol. Synapse counts (electron microscopy), dendritic arborisation (Golgi–Cox), and network connectivity were measured in mice (age 28 days) previously exposed to propofol at postnatal day 5–7. Memory was assessed in adult mice (age 3 months) previously exposed to propofol at postnatal day 5–7.
Propofol increased RhoA activation, collapsed growth cones, and impaired retrograde axonal transport of quantum dot-labelled brain-derived neurotrophic factor, all of which were prevented with TAT-C3. Adult mice previously treated with propofol had decreased numbers of total hippocampal synapses and presynaptic vesicles, reduced hippocampal dendritic arborisation, and infrapyramidal mossy fibres. These mice also exhibited decreased hippocampal-dependent contextual fear memory recall. All anatomical and behavioural changes were prevented with TAT-C3 pre-treatment.
Inhibition of RhoA prevents propofol-mediated hippocampal neurotoxicity and associated cognitive deficits.
Macroalgal beds can be vertically differentiated into canopy and understory strata, and each can exhibit different phenology in algal biomass and morphology. Thus, for epibenthic invertebrates, ...macroalgal beds provide both vertically and seasonally heterogenous habitats, and epibenthic assemblages can be predicted to show different patterns of seasonal dynamics reflecting the different effects of algal phenology between the canopy and understory. We described and compared the seasonal dynamics of gammarid assemblages and algal phenology in the canopy and understory of a Sargassum bed in Otsuchi Bay, Japan. Gammarid assemblages showed distinctly different seasonal dynamics in abundance and species composition between the 2 habitats. In the canopy, gammarid abundance peaked in July, which was mainly explained by fluctuations in abundance of the dominant tube-dwelling filter-feeder Jassa morinoi. In the understory, gammarid abundance peaked in August−September, clearly later than in the canopy, and was also dominated by tube-dwelling filter-feeders, but different species such as Monocorophium uenoi and Gammaropsis japonicus. These differences in assemblage dynamics of gammarids can be ex plained by the Sargassum defoliation in late summer, resulting in decreased habitat space and complexity for gammarids in the canopy. In the understory, however, Sargassum defoliation in creased the amount of detrital deposition, providing food sources and additional habitat for gammarids. This study demonstrates that algal phenology can have strong but different effects on epibenthic invertebrates inhabiting canopy and understory strata.
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