152 research outputs found

    On the notion of validity for the bilateral classical logic

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    This paper considers Rumfitt’s bilateral classical logic (BCL), which is proposed to counter Dummett’s challenge to classical logic. First, agreeing with several authors, we argue that Rumfitt’s notion of harmony, used to justify logical rules by a purely proof theoretical manner, is not sufficient to justify coordination rules in BCL purely proof-theoretically. For the central part of this paper, we propose a notion of proof-theoretical validity similar to Prawitz for BCL and proves that BCL is sound and complete respect to this notion of validity. The major difficulty in defining validity for BCL is that validity of positive +A appears to depend on negative −A, and vice versa. Thus, the straightforward inductive definition does not work because of this circular dependance. However, Knaster-Tarski’s fixed point theorem can resolve this circularity. Finally, we discuss the philosophical relevance of our work, in particular, the impact of the use of fixed point theorem and the issue of decidability

    X線による楕円銀河M86周辺の広がった放射の研究

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    13301甲第4553号博士(理学)金沢大学博士論文本文Ful

    X線による楕円銀河M86周辺の広がった放射の研究

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    13301甲第4553号博士(理学)金沢大学博士論文要旨Abstrac

    Association between elevated serum transaminase and moderately increased albuminuria : a cross-sectional study in western Tokushima, Japan

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    Background This study aimed to identify the factors relating to moderately increased albuminuria among middle-aged and older individuals in Japan. Methods We conducted specific health examinations in which we measured albuminuria levels, and administered a questionnaire survey to record participants’ lifestyles in western Tokushima Prefecture, Japan. A total of 1,660 people whose albuminuria was less than 300 mg/g creatinine (Cr) were analyzed. We divided participants into two groups—those with normal albuminuria ( 300 mg/gCr)—and compared their characteristics. To investigate all relevant factors, we conducted a multivariate logistic regression analysis. Results The moderately increased albuminuria group were significantly older and had, among them, significantly higher percentages of a body mass index (BMI) ≥ 25 kg/m2, diabetes, hypertension, and mild liver disorder (aspartate transaminase ≥ 31 U/L or alanine aminotransferase ≥ 31 U/L or gamma-glutamyl transferase ≥ 51 U/L). (p < 0.01) In a multivariate logistic regression analysis that used microalbuminuria as an independent variable, we found the adjusted odds ratio (AOR) and 95% confidence interval (CI) to be significantly higher among individuals with diabetes (AOR: 2.04, 95% CI: 1.40–2.99); hypertension (AOR: 1.90, 95% CI: 1.36–2.65); BMI ≥ 25 kg/m2 (AOR: 1.76, 95% CI: 1.27–2.44); and mild liver disorder (AOR: 1.54, 95% CI: 1.10–2.18). Conclusions In addition to diabetes, hypertension, and BMI ≥ 25 kg/m2, this study found that among the middle-aged and older general population living in western Tokushima Prefecture, there were cases of mild liver disorder (elevated serum transaminase), which independently associated with moderately increased albuminuria. Therefore, in health checkups targeting the general population, there is a need to consider measuring albuminuria, even in those who have only mild liver dysfunction (health guidance level)

    Structural and dynamic behavior of lithium iron polysulfide Li₈FeS₅ during charge–discharge cycling

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    Lithium sulfide (Li₂S) is one of the promising positive electrode materials for next-generation rechargeable lithium batteries. To improve the electrochemical performance of electronically resistive Li₂S, a Fe-doped Li₂S-based positive electrode material (Li₈FeS₅) has been recently designed and found to exhibit excellent discharge capacity close to 800 mAh g⁻¹. In the present study, we investigate the structural and dynamic behavior of Li₈FeS₅ during charge–discharge cycling. In Li₈FeS₅, Fe ions are incorporated into the Li₂S framework structure. The Li₂S-based structure is found to transform to an amorphous phase during the charge process. The delithiation-induced amorphization is associated with the formation of S-S polysulfide bonds, indicating charge compensation by S ions. The crystalline to non-crystalline structural transformation is reversible, but Li ions are extracted from the material via a two-phase reaction, although they are inserted via a single-phase process. These results indicate that the delithiation/lithiation mechanism is neither a topotactic extraction/insertion nor a conversion-type reaction. Moreover, the activation energies for Li ion diffusion in the pristine, delithiated, and lithiated materials are estimated to be in the 0.30–0.37 eV range, which corresponds to the energy barriers for local hopping of Li ions along the Li sublattice in the Li₂S framework

    Microscopic characterization of the C–F bonds in fluorine–graphite intercalation compounds

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    The structures of fluorine–graphite intercalation compounds (F-GICs, C₂.₈F and C₃.₅F) have been analyzed by high-resolution transmission electron microscopy (TEM). Cross-sectional TEM images of the F-GICs indicate that the interlayer distance increases by insertion of fluorine with randomly buckled carbon layers. Such a structure can form by alternation in the bond angle at a carbon atom covalently bonded with fluorine. Electron energy loss spectroscopy combined with TEM indicates that the π-orbital network over the graphitic carbon layer reduces with fluorination. The C–F bond is essentially covalent

    Carbon Nanotube/Nanofibers and Graphite Hybrids for Li-Ion Battery Application

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    To improve the electrical conductivity of negative electrodes of lithium ion batteries, we applied a direct CVD synthesis of carbon nanomaterials on the surface of graphite particles. To prepare a catalyst, two alternative approaches were utilized: colloidal nanoparticles (NPs) and metal (Ni and Co) nitrate salt precursors deposited on the graphite surface. Both colloidal and precursor systems allowed us to produce carbon nanofibers (CNFs) on the graphite surface with high coverage under the optimum CVD conditions. Electrical measurements revealed that the resistivity of the actual electrodes fabricated from CNFs coated graphite particles was about 40% lower compared to the original pristine graphite electrodes.Peer reviewe

    Oxidation behaviour of lattice oxygen in Li-rich manganese-based layered oxide studied by hard X-ray photoelectron spectroscopy

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    The oxidation/reduction behaviours of lattice oxygen and transition metals in a Li-rich manganese-based layered oxide Li[Li0.25Ni0.20Mn0.55]O1.93 are investigated by using hard X-ray photoelectron spectroscopy (HAX-PES). By making use of its deeper probing depth rather than in-house XPS analyses, we clearly confirm the formation of O- ions as bulk oxygen species in the active material. They are formed on the 1st charging process as a charge compensation mechanism for delithiation and decrease on discharging. In particular, the cation-anion dual charge compensation involving Ni and O ions is suggested during the voltage slope region of the charging process. The Ni ions in the material are considered to increase the capacity delivered by a reversible anion redox reaction with the suppression of O2 gas release. On the other hand, we found structural deterioration in the cycled material. The O- species are still observed but are electrochemically inactive during the 5th charge-discharge cycle. Also, the oxidation state of Ni ions is divalent and inactive, although that of Mn ions changes reversibly. We believe that this is associated with the structural rearrangement occurring after the activation process during the 1st charging, leading to the formation of spinel- or rocksalt-like domains over the sub-surface region of the particles
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