173 research outputs found
Bicontinuous Isomorphisms between Two Closed Left Ideals of a Compact Dual Ring
No full textA quasi-Frobenius ring is a ring with minimum condition satisfying the conditions r(l)H)) = H and l(r(L)) = L for right ideals H and left ideals L where r(S) (l(S)) denotes the right (left) annihilator of a subset S of the ring. Nakayama first defined and studied such rings (8; 9) and they have been studied by a number of authors (2; 3; 4; 6). A dual ring is a topological ring satisfying the conditions r(l)H)) = H and l(r)H)) = L for closed right ideals H and closed left ideals L. Baer (1) and Kaplansky (7) introduced the notion of such rings, which is a natural generalization of that of quaso-Frobenius rings. Numakura studied the analogy between dual rings and quasi-Frobenius rings in (10).</jats:p
Effects of Aging Temperature on Electrical Conductivity and Hardness of Cu-3 at. pct Ti Alloy Aged in a Hydrogen Atmosphere
No full textTo improve the balance of the electrical conductivity and mechanical strength for dilute Cu-Ti alloys by aging in a hydrogen atmosphere, the influence of aging temperature ranging from 673 K to 773 K (400 °C to 500 °C) on the properties of Cu-3 at. pct Ti alloy was studied. The Vickers hardness increases steadily with aging time and starts to fall at 3 hours at 773 K (500 °C), 10 hours at 723 K (450 °C), or over 620 hours at 673 K (400 °C), which is the same as the case of conventional aging in vacuum. The maximum hardness increases from 220 to 236 with the decrease of aging temperature, which is slightly lower than aging at the same temperature in vacuum. The electrical conductivity at the maximum hardness also increases from 18 to 32 pct of pure copper with the decrease of the temperature, which is enhanced by a factor of 1.3 to 1.5 in comparison to aging in vacuum. Thus, aging at 673 K (400 °C) in a hydrogen atmosphere renders fairly good balance of strength and conductivity, although it takes nearly a month to achieve. The microstructural changes during aging were examined by transmission electron microscopy (TEM) and atom-probe tomography (APT), it was confirmed that precipitation of the Cu4Ti phase occurs first and then particles of TiH2 form as the third phase, thereby efficiently removing the Ti solutes in the matrix
A Bragg–Williams model for the thermodynamic activity and the thermodynamic factor in diffusion for ordered alloys with substitutional defects
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Physical inactivity is associated with decreased growth differentiation factor 11 in chronic obstructive pulmonary disease
No full textRie Tanaka,1 Hisatoshi Sugiura,1 Mitsuhiro Yamada,1 Tomohiro Ichikawa,1 Akira Koarai,1 Naoya Fujino,1 Satoru Yanagisawa,1 Katsuhiro Onodera,1 Tadahisa Numakura,1 Kei Sato,1 Yorihiko Kyogoku,1 Hirohito Sano,1 Shun Yamanaka,1 Tatsuma Okazaki,1 Tsutomu Tamada,1 Motohiko Miura,2 Tsuneyuki Takahashi,3 Masakazu Ichinose1 1Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Aoba-ku, Sendai, Japan; 2Department of Respiratory Medicine, Tohoku Rosai Hospital, Aoba-ku, Sendai, Japan; 3Department of Internal Medicine, Tohoku Medical and Pharmaceutical University Wakabayashi Hospital, Wakabayashi-ku, Sendai, Japan Background: Growth differentiation factor 11 (GDF11) is reported to possess anti-aging and rejuvenating effects, including muscle regeneration and to be highly expressed in skeletal muscle. Recently, we demonstrated that the levels of plasma GDF11 were decreased in COPD. However, the effect of decreased circulating GDF11 in the pathophysiology of COPD remains unknown. The aim of this study is to investigate the association between the plasma GDF11 levels and various clinical parameters in patients with COPD. Patients and methods: Eighteen ex-smokers as control subjects and 70 COPD patients participated in the current study. We measured the levels of plasma GDF11 using immunoblotting, lung function, physical activity using a triaxial accelerometer, quadriceps strength, exercise capacity, and systemic inflammatory markers. We investigated the association between the levels of plasma GDF11 and these clinical parameters. Results: The levels of plasma GDF11 in the COPD patients had significant positive correlations with the data of lung function. Furthermore, the levels of plasma GDF11 were significantly correlated with the physical activity, quadriceps strength, and exercise capacity. Moreover, the levels of plasma GDF11 were significantly correlated with the data of inflammatory markers. Although various factors were related to GDF11, the multiple regression analysis showed that physical activity was significantly associated with the levels of plasma GDF11. Conclusion: Physical inactivity was significantly related to the decreased GDF11 levels in COPD, which might be useful for understanding the pathogenesis of COPD. Clarifying the relationships between the physical inactivity and GDF11 may reveal a potentially attractive therapeutic approach in COPD via increasing the plasma levels of GDF11. Keywords: physical activity, muscle strength, rejuvenating factor, COP
Removal of oxygen and nitrogen from niobium by external gettering
No full textExternal gettering has a potential to remove interstitial gaseous impurities from solid niobium even below 1500K. The oxygen concentration in the deposit and the Nb bulk is evaluated by a combination of material thermodynamics and mass balance. The removal of oxygen and nitrogen was experimentally studied by using Ti, Y, Zr, Al and Si. Titanium deposited smoothly on the Nb surface in vacuum, and absorbed the gaseous impurities most efficiently. By applying Ti as an external getter on commercial niobium at 1463K, the residual resistivity ratio (RRR) reached 780. The oxygen distribution was calculated by combining thermodynamics and diffusion data. The experimental deoxidation rate was found to be slower than the calculated value. This may be attributed to the slow growth of the deposited layer, its morphology, and the interdiffused Ti-Nb alloy layer
The homogeneity ranges of the L1(2)-type intermetallic compounds Ni3Ga and Ni3Ge
No full textThe homogeneity ranges of the L12-ordered compounds Ni3Ga and Ni3Ge and the boundaries of the neighboring phases have been examined by electron probe microanalysis using heterophase alloys in the temperature ranges 1073 to 1373 K (Ni-Ga) and 1073 to 1346 K (Ni-Ge). The composition ranges of the L12-ordered phases have been found to be narrower than those reported in the literature, on the Ga-rich side for Ni3Ga and on the Ge-deficient side for Ni3Ge
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