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991.
Hiroko Kominami Takahisa Yamasaki Yoichiro Nakanishi Kazuhiko Hara 《Journal of luminescence》2012,132(12):3100-3102
In this study, the detailed crystallization mechanism of SrGa2S4: Eu2+ thin film phosphors annealed by Nd:YAG laser (355 nm) was examined. Using the spectral transmittance measurements of SrS and Ga2S3 thin films, the influence of temperature on SrGa2S4 thin film formation by laser irradiation was investigated using the thermal conducting equation. From the calculation, it is thought that Ga2S3 absorbed greater laser energy than SrS and generated the heat. By diffusing heat throughout the thin film, crystallization was promoted. 相似文献
992.
993.
Beom-Seok Ko Kimio Yoshimura Akihiro Hiroki Yasunari Maekawa 《Journal of polymer science. Part A, Polymer chemistry》2021,59(1):108-116
The radiation-induced graft polymerization (RGP) of styrene into poly(ethylene-co-tetrafluoroethylene) films was performed at various monomer concentrations and solvents at 60 °C. The grafted polystyrene (g-PS) was isolated using the swelling-induced detachment phenomenon, and the number-averaged molecular weight (Mn) and the number of g-PS (Np) were determined using gel permeation chromatography. The Mn increased consistently with an increase in the grafting time up to 2–3 hours, indicating very low termination rates, which was a result of the “gel effect”. This is the first direct evidence of the gradual Mn increase over time using RGP in thermally and chemically stable polymer films such as fluorinated polymers. When the Mn and Np were plotted as a function of the degree of grafting (DOG), sudden Np drops along with rapid Mn increases were observed in the DOG region of 80–90%, indicating negligible initiation and propagation; however, a recombination termination between two propagating g-PS radicals dominated the later part of the grafting process. Further increases in both Mn and Np were observed subsequently, implying that reinitiation and propagation events were triggered by morphological changes, as observed by small- and ultrasmall-angle X-ray scattering experiments, which liberated the dormant radicals from the lamellar crystals. 相似文献
994.
Jitsuro Sugie Tsunehiko Shimadu Takashi Yamasaki 《Journal of Dynamics and Differential Equations》2012,24(4):777-802
A necessary and sufficient condition is established for the equilibrium of the damped superlinear oscillator $$x^{\prime\prime} + a(t)\phi_q(x^{\prime}) + \omega^2x = 0$$ to be globally asymptotically stable. The obtained criterion is judged by whether the integral of a particular solution of the first-order nonlinear differential equation $$u^{\prime} + \omega^{q-2}a(t)\phi_q(u) + 1 = 0$$ is divergent or convergent. Since this nonlinear differential equation cannot be solved in general, it can be said that the presented result is expressed by an implicit condition. Explicit sufficient conditions and explicit necessary conditions are also given for the equilibrium of the damped superlinear oscillator to be globally attractive. Moreover, it is proved that a certain growth condition of a(t) guarantees the global asymptotic stability for the equilibrium of the damped superlinear oscillator. 相似文献
995.
Hiroki Yoshida 《International Journal of Computational Fluid Dynamics》2013,27(4):229-239
The purpose of this paper is to determine the shape of an oscillating body by minimising drag and lift forces, located in a transient incompressible viscous fluid flow by means of the Arbitrary Lagrangian Eulerian finite element method and an optimal control theory. A performance function is expressed by the drag and lift forces. The performance function should be minimised satisfying the state equation and the constant volume condition. Therefore, this problem can be transformed into a minimisation problem without constraint by the Lagrange multiplier method. The adjoint equation and the gradient of the performance function are used to update the shape of the body. In this study, as a minimisation technique, the weighted gradient method is applied. The final shape is obtained of which drag and lift forces are reduced by 66.2% and 92.8%, respectively. The final shape obtained by this study is compared with the final shape of the non-oscillating body. The obtained final shape of the oscillating body is significantly different from the non-oscillating body. 相似文献
996.
Masanori Kameyama Hiroki Ichikawa Arata Miyauchi 《Theoretical and Computational Fluid Dynamics》2013,27(1-2):21-40
A linear stability analysis was performed in order to study the onset of thermal convection in the presence of a strong viscosity variation, with a special emphasis on the condition for the stagnant-lid (ST) convection where a convection takes place only in a sublayer beneath a highly viscous lid of cold fluid. We consider the temporal evolution (growth or decay) of an infinitesimal perturbation superimposed to a Boussinesq fluid with an infinite Prandtl number which is in a static (motionless) and conductive state in a basally heated planar layer or spherical shell. The viscosity of the fluid is assumed to be exponentially dependent on temperature. The linearized equations for conservations of mass, momentum, and internal (thermal) energy are numerically solved for the critical Rayleigh number, Ra c , as well as the radial profiles of eigenfunctions for infinitesimal perturbations. The above calculations are repeatedly carried out by systematically varying (i) the magnitude of the temperature dependence of viscosity, E, and (ii) the ratio of the inner and outer radii of the spherical shell, γ. A careful analysis of the vertical structure of incipient flows demonstrated that the dominance of the ST convection can be quantitatively identified by the vertical profile of Δ h (a measure of conversion between horizontal and vertical flows), regardless of the model geometries. We also found that, in the spherical shell relevant to the Earth’s mantle (γ = 0.55), the transition into ST convection takes place at the viscosity contrast across the layer ${r_\eta\simeq10^4}$ . Taken together with the fact that the threshold value of r η falls in the range of r η for a so-called sluggish-lid convection, our finding suggests that the ST-mode of convection with horizontally elongated convection cells is likely to arise in the Earth’s mantle solely from the temperature-dependent viscosity. 相似文献
997.
A. Hiroki H.T. Tran N. Nagasawa T. Yagi M. Tamada 《Radiation Physics and Chemistry》2009,78(12):1076-1080
Blend hydrogels based on the carboxymethyl cellulose (CMC) and carboxymethyl chitosan (CMCts) were prepared by γ-irradiation of a high concentrated CMC/CMCts aqueous solution. Properties of the hydrogels, such as gel fraction, swelling ratio, gel strength, and metal adsorption for Pb and Au were investigated. The gel fraction increased with increasing dose, while the swelling ratio decreased with increasing it. The obtained blend hydrogels had high adsorption performance which was controlled by adjusting the composition of CMC/CMCts. 相似文献
998.
Kazuhiro Uemura Fumiaki Onishi Yukari Yamasaki Hidetoshi Kita 《Journal of solid state chemistry》2009,182(10):2852-5109
NO2 containing dicarboxylate bridging ligands, nitroterephthalate (bdc-NO2) and 2,5-dinitroterephthalate (bdc-(NO2)2), afford porous coordination polymers, {[Zn2(bdc-NO2)2(dabco)]·solvents}n (2⊃solvents) and {[Zn2(bdc-(NO2)2)2(dabco)]·solvents}n (3⊃solvents). Both compounds form jungle-gym-type regularities, where a 2D square grid composed of dinuclear Zn2 units and dicarboxylate ligands is bridged by dabco molecules to extend the 2D layers into a 3D structure. In 2⊃solvents and 3⊃solvents, a rectangle pore surrounded by eight Zn2 corners contains two and four NO2 moieties, respectively. Thermal gravimetry (TG) and X-ray powder diffraction (XRPD) measurements reveal that both compounds maintain the frameworks regularities without guest molecules and with solvents such as MeOH, EtOH, i-PrOH, and Me2CO. Adsorption measurements reveal that dried 2 and 3 adsorb H2O molecules to be {[Zn2(bdc-NO2)2(dabco)]·4H2O}n (2⊃4H2O) and {[Zn2(bdc-(NO2)2)2(dabco)]·6H2O}n (3⊃6H2O), showing the pore hydrophilicity enhancement caused by NO2 group introduction. 相似文献
999.
The drying dissipative patterns of aqueous solutions of simple electrolytes, KCl, NaCl, CaCl2, and LaCl3, were observed on a cover glass. The macroscopic broad rings were formed at the outside edge of the drying film area, which
shrunk from the initial solution area especially at low salt concentrations. The drying area and the broad ring size decreased
as the salt concentration decreased. The microscopic block-like and dendritic cross-like patterns were observed for all the
salts. Size of single crystals dried on a cover glass increased as salt concentration increased. The drying patterns of the
binary mixtures of the salts were also observed. Size of the broad ring increased sharply by mixing. The microscopic patterns
were, on the other hand, insensitive to the mixing. 相似文献
1000.
Hiroki Matsubara Hiroki Takumi Teijiro Takamatsu Takanori Takiue Makoto Aratono 《Colloid and polymer science》2009,287(9):1077-1082
The surface tension of aqueous solutions of tetraethyleneglycol octyl ether (C8E4) and octyl-β-d-maltopyranoside (OM) mixture was measured as a function of the total molality of surfactants and the composition of OM under
atmospheric pressure at 298.15 K by drop volume technique. The results of surface tension measurements were analyzed by originally
developed thermodynamic equations, then phase diagrams of adsorption and micelle formation were constructed. From the analysis
of the surface tension data, it was found that the C8E4 and OM molecules interact attractively in the adsorbed film and the
excess Gibbs energy of adsorption can be compared with those observed in typical cationic–nonionic surfactant systems; nevertheless,
they are mixed almost ideally in the mixed micelle. Judging from a negative excess surface area calculated by differentiating
the excess Gibbs energy by the surface tension, we concluded that the attraction between C8E4 and OM molecules is a short-range
one originated in the hydrogen bonding between them which favors the planar configuration. 相似文献