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71.
K Murakawa R Izumi K Noma C Tashiro T Minatogawa M Amatsu 《Canadian Metallurgical Quarterly》1995,45(5):801-809
This study evaluates the circulatory effects of electrical stimulation of the cervical sympathetic trunks on blood flow in the common carotid artery and facial nerve tissue in dogs. Marked increases in arterial pressure and heart rate were observed due to electrical stimulation of the cervical sympathetic trunks, while blood flow volume in the common carotid artery and in the facial nerve tissue decreased markedly. It was assumed that microcirculation of the facial nerve is definitely impaired by electrical stimulation of the cervical sympathetic trunks, and the tonicity of the sympathetic nervous system appears to be a major factor in changes in the microcirculation of the facial nerve. It is well known that impaired circulation in the nutrient vessels of the facial nerve has an important effect on the pathogenesis of facial palsy. The hypertonicity of the sympathetic nervous system is closely involved in the onset of facial palsy. 相似文献
72.
1. The effects of dopamine on the L-type Ca2+ current (ICa,L) of both atrial and ventricular single myocytes and on the force of contraction of atrial trabeculae in rat heart were investigated. 2. Dopamine increased atrial ICa,L at concentrations higher than 1 microM, but had little or no effect on ICa,L at lower concentrations. The increase in ICa,L at high concentrations was reversed by propranolol and acetylcholine, but not by phentolamine. Activation and inactivation kinetics of ICa,L were not altered by dopamine. 3. In rat ventricular myocytes in which the D4 receptor mRNA does not express, dopamine (20-100 microM) also increased the ICa,L amplitude and propranolol reversed this effect. 4. Clozapine, a potent D4 receptor antagonist, blocked the augmenting effect of dopamine on ICa,L. However, this effect could be explained by beta-antagonism, since clozapine also inhibited the isoprenaline effect. 5. In the atrial trabeculae, the increase in contraction by dopamine (1 to 30 microM) was reversed by 1 microM propranolol, but not by 2 microM phentolamine. Low doses of dopamine (0.01 to 0.3 microM) did not affect the contraction in the controls or during a modest stimulation of the beta-adrenoceptor with 0.01 microM isoprenaline. 6. These results indicate that the positive inotropic action of dopamine is mediated through direct stimulation of the beta-adrenoceptor in both atrial and ventricular myocytes. Involvement of D4 receptor appears unlikely in the regulation of the atrial contraction. 相似文献
73.
74.
Yoji Koike Shuichi Takeuchi Hidetaka Sato Yuichiro Hama Masatsune Kato Yasuhiro Ono Susumu Katano 《Journal of Low Temperature Physics》1996,105(3-4):317-322
The effects of substitution of Y or Bi on the low-temperature structural phase transition, electronic anomaly and superconductivity have been studied in La2-y-xYyBaxCuO La2-y-xBiyBaxCuO4 and La1.9-y-xTb0.1BiySrxCuO4 with x = 1/8. Moreover, an electronic anomaly, which is analogous to those observed in La2–xBaxCuO4 and La1.6-xNd0.4SrxCuO4 with x 1/8, has been found below about 60 K in the thermoelectric power measurements for the Zn-substituted La2–xSrxCu1–yZnyO4 with x 0.115 and y = 0.01 – 0.02. These experimental results support the conclusions by Tranquada et al. that static order of the stripe correlations of holes and spins, owing to pinning by the low-temperature structure or impurities (Zn in this case), is the origin of the electronic anomaly, leading to the suppression of superconductivity. 相似文献
75.
Tadayoshi Matsumori Atsushi Kawamoto Tsuguo Kondoh Tsuyoshi Nomura Hidetaka Saomoto 《Structural and Multidisciplinary Optimization》2017,56(3):619-629
This paper deals with a design method for boundary shapes using filtering techniques based on a partial differential equation (PDE). In shape optimization, it is known that oscillatory boundaries appear when design variables are directly assigned to the design boundaries. In addition, during the optimization process, discretized elements in a computational domain are distorted due to extremely large shape changes along the design boundaries. The distorted elements may cause accuracy deterioration or numerical instability in a forward problem. In this paper, we propose a shape optimization method by using the PDE as a low pass filter which prevents the oscillatory boundaries of the optimized design. For restricting the shape distortion of the discretized elements, the shear deformation of the elements is constrained in the optimization problem. Mathematical programming is used to find the boundary shapes under the KKT conditions. The effectiveness of the proposed method is demonstrated through numerical examples in solid and fluid mechanics. 相似文献
76.
Effect of the (Ba + Sr)/Ti ratio on the microwave‐tunable properties of Ba0.6Sr0.4TiO3 ceramics 下载免费PDF全文
Takashi Teranishi Riku Kanemoto Hidetaka Hayashi Akira Kishimoto 《Journal of the American Ceramic Society》2017,100(3):1037-1043
The impact of the (Ba + Sr)/Ti (A/B) ratio on the microwave‐tunable characteristics of diffuse phase transition (DPT) ferroelectric Ba0.6Sr0.4TiO3 (0.6‐BST) ceramics was investigated. The reduction in the lattice constant with increasing nonstoichiometry was attributed to introduced partial Schottky defects, i.e., and . The magnitude of the dielectric constant, ε′, at room temperature in the absence of an applied electric field was governed by the shift in the dielectric maximum temperature, Tm, because Tm was close to room temperature for the 0.6‐BST. The dielectric loss, tanδ, diminished as the ε′ decreased for 0.98≤A/B≤1.05, while the tanδ was much higher for A/B=0.95 having the greatest A‐site vacancy loading. The negatively charged and were mainly compensated by oxygen vacancies and likely partly compensated by holes, h?, which contributed to the electrical conduction. The tunability, T, at 100 MHz was almost constant at 20%–25% for A/B≥1.00 despite the reduction of the ε′, whereas T decreased for A/B<1.00 to ca. 10% for A/B=0.95 having the greatest A‐site vacancy loading. The results implied that the for larger A/B values was more efficient in generating nucleation sites in the polar nanoregions (PNRs) than the for smaller A/B values, thereby providing greater dipole polarization. Consequently, the figure of merit, FOM, reached its maximum of 250 at A/B=0.9875, which was ca. 155% higher than that of the stoichiometric BST. 相似文献
77.
78.
Hidetaka Uehara Tomomi Suganuma Satoshi Negishi Satoru Ueno Kiotaka Sato 《Journal of the American Oil Chemists' Society》2006,83(3):261-267
Conjugated linoleic acid (CLA) is commercially available as a mixture consisting of almost equal amounts of the cis-9,trans-11-CLA (c9, t11) and trans-10, cis-12-CLA (t10, c12) isomers. Separation of the two isomers is highly significant since each exhibits different biochemical properties. Highly
efficient separation could be accomplished by crystallization in acetone (solvent) of the two CLA isomers (solutes) in the
presence of medium-chain fatty-acid (MCFA) additives. The relative concentration ratios of the two CLA isomers in the solvent-crystallized
materials varied depending on which MCFA were added. Addition of lauric and decanoic acids resulted in the crystals predominantly
containing t10,c12, whereas octanoic acid yielded those predominantly containing c9,t11. We have confirmed that onetime solvent crystallization using decanoic acid and octanoic acid additives increased the t10,c12 and c9,t11 concentrations, and that repeated solvent crystallization resulted in the ratio of c9,t11 to t10,c12 of at least 4∶96 or 98∶2. 相似文献
79.
To prepare hard and transparent poly (methyl methacrylate)‐silica coat film on glass or polycarbonate substrates, poly(methyl methacrylate‐co‐2‐hydroxyethyl methacrylate) random copolymers and perhydropolysilazane (PHPS) were blended in solution. Then the solution was cast on the substrates. The grafting of PHPS onto 2‐hydroxyethyl methacrylate unit was analyzed by 1H NMR spectroscopy. Surface hardness and transparency of the coat film were measured by nano‐indentation method and UV‐Vis spectroscopy, respectively. Surface hardness of coat film depended on the volume fraction of silica in the coat film, and reached 2.7 GPa when the volume fraction of silica was 76.4%. Transparency of the coat films prepared with PHPS was almost 100%, indicating that the coat film prepared with PHPS was highly transparent not only on glass substrate but also on the polycarbonate substrate. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
80.
Mezame Shibata Masaharu Kato Hiroshi Seto Tatsuo Noma Masahiro Yoshimura Shigeyuki Sōmiya 《Journal of Materials Science》1987,22(4):1432-1436
The effects of the external stress on the displacive cubic (c) to tetragonal (t) transformation, taking place during rapid quenching of ZrO2-Y2O3 alloys by a hammer-anvil unit, were examined through the statistical analysis of the crystallography of the product phases. The initially formed c-phase had no strong texture with respect to the stress direction. However, specific t variants among crystallographically equivalent ones were formed preferentially. From these observations, it is concluded that the applied stress plays an important role on the deformation to change the lattice during the c t transformation. 相似文献