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31.
Manabu Tsuburaya 《Polymer》2004,45(3):1027-1032
We found that amorphous polycarbonate (PC) can be crystallized in several minutes by blending poly(ethylene oxide) (PEO). When the blends were annealed in the two-phase region below the upper critical solution temperature, highly interconnected two-phase structure characteristic of the spinodal decomposition was developed and then the crystallization occurred in the PC-rich phase during the spinodal decomposition. As the molecular weight of PEO decreased, the crystallization rate decreased and the crystallizable temperature became narrower in spite of the acceleration of the polymeric segmental motion. These results suggest that the crystallization of the PC is not induced by the acceleration of the polymeric segmental motion, but by the up-hill diffusion of the liquid-liquid phase separation via spinodal decomposition. Owing to the competitive progress of the crystallization and the spinodal decomposition, the melting peak of the PC crystallites shifted to lower temperature with increasing annealing temperature. 相似文献
32.
33.
Manabu Gotoh 《Metals and Materials International》1998,4(4):628-639
Various types of behavior due to plastic instability under uniaxial tension and compression are numerically investigated regarding
sheet materials, plane strain blocks, and cylindrical bars and hollow cylinders. The code GOLDA for analysis of large elastic-plastic
deformation previously developed by the author is used, which is one of quasi-static explicit FEM programs. Both of diffuse
type and localized type of instability are concerned with. The role of vertex-hardening in plastic instability is payed attention,
by using the J2G (J2-Gotoh’s corner theory) as the plasticity constitutive equation, which was proposed previously by the
author and is a kind of vertex-hardening theory. Following results are mainly derived. 1) In plane strain tension, shear-type
strain localization is realized by the use of J2G, but not by the conventional J2F (J2-flow theory). In axisymmetric tension
of a cylindrical solid bar, however, such strain localization would never appear even by J2G, as expected by the experiment.
2) In axisymmetric tension of a hollow cylinder under the condition of no contractlion of its bore (therefore, in almost plane
strain state with no circumferential strain), it is found that shear-type strain localization could occur. This is realized
again by the use of J2G, whereas J2F never allows such strain localization. 3) In compression under the embedded edges condition,
it is found that a sheet with initial aspect ratio of 2:1 (in height:breadth) yields double barreling, whereas a plane strain
block yields double barreling at the initial aspect ratio of 3:1, not at 2:1 though expected from the conventional slip-line
theory. As for a cylindrical solid bar, double barreling appears for the initial aspect ratio of 2:1 but only for higher n-vaiue
(the strain hardening exponent), say n=0.5. 4) As for barreling mode, when thick-walled axisymmetric tubes with the initial
ratio of thickness to inner diameter 1/5 to 1/3 are compressed axially, corresponding to the initial aspect ratios of 3:1,
2:1 and 1:1, triple barreling, double barreling and single barreling appear, respectively. 5) It is found that thin-walled
tubes buckle in a progressive periodic mode with almost stationary compressive load under axial compression. Thus it can be
used as a simplified model for buckling of more complex structures such as the honeycomb. 相似文献
34.
提出用边界积分方程法(boundary integral equation method,BIEM)进行圆弧齿轮强度分析的设汁方法。在研究中依据弹性理论的柯西型积分,建立适合于各种载荷作用轮齿不同位置的齿轮强度分析数学模型。在理论方程式建模中采用间接式边界积分方程法,以应力函数作为解析对象,直接求解齿轮应力、轮齿刚度变形等。文中方法具有理论公式推导简捷、软件设计容易、使用方便的优点。本研究还进行了软件设计和实例应用解析,并通过与其他方法的结果比较证实本方法正确有效和实用价值。 相似文献
35.
Muneyuki Naito Manabu Ishimaru 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2009,267(8-9):1290-1293
Crystallization processes of amorphous Fe–Si layers have been investigated using transmission electron microscopy (TEM). Si(1 1 1) substrates were irradiated with 120 keV Fe ions at ?150 °C to a fluence of 1.0 × 1017 cm2. An Fe-rich amorphous layer embedded in an amorphous Si was formed in the as-irradiated sample. Plan-view TEM observations revealed that a part of the amorphous Fe–Si layer crystallized to the metastable α-FeSi2 after thermal annealing at 350 °C for 8 h. The lattice parameter of c-axis decreased with thermal annealing. It was considered that the change in the lattice parameter originates from the decrease of the Fe occupancy at (0, 0, 1/2) and its equivalent positions in the unit cell of the metastable α-FeSi2. 相似文献
36.
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38.
Chang-eun Kim Ken Kurosaki Manabu Ishimaru Hiroaki Muta Shinsuke Yamanaka 《Journal of Electronic Materials》2011,40(5):999-1004
Our group has focused attention on Ga2Te3 as a natural nanostructured thermoelectric material. Ga2Te3 has basically a zincblende structure, but one-third of the Ga sites are structural vacancies due to the valence mismatch
between Ga and Te. It has been confirmed that (1) vacancies in Ga2Te3 exist as two-dimensional (2D) vacancy planes, and (2) Ga2Te3 exhibits an unexpectedly low thermal conductivity (κ), most likely due to highly effective phonon scattering by the 2D vacancy planes. However, the effect of the size and periodicity
of the 2D vacancy planes on κ has been unclear. In addition, it has also been unclear whether only the 2D vacancy planes reduce κ or if point-type vacancies can also reduce κ. In the present study, we tried to prepare Ga2Te3 and Ga2Se3 with various vacancy distributions by controlling annealing conditions. The atomic structures of the samples were characterized
by means of transmission electron microscopy, and κ was evaluated from the thermal diffusivity measured by the laser flash method. The effects of vacancy distributions on κ of Ga2Te3 and Ga2Se3 are discussed. 相似文献
39.
采用了微量润滑技术的钻削在长距或小孔径的条件下有必要对所供给的油雾和压缩空气进行最佳化分析.本文首先对切削变形与切削热分布的总能量进行了分析,并在把普通钻削过程中油雾假设为稳态可压缩绝热紊流状态的假设条件下,通过分析得到油膜厚度、气流速度、压缩空气温度和刀具平均温度等重要影响参数的相互关系.最后,给出微量润滑钻削条件下,切削过程中所需的油膜和压缩空气的最佳容量. 相似文献
40.
Manabu Nishijima Irina D. Gocheva Shigeto Okada Takayuki Doi Jun-ichi Yamaki Tetsuaki Nishida 《Journal of power sources》2009,190(2):558-562
Fluorine compounds have high discharge voltage due to its highly ionic metal-ligand bonds. In them, perovskite-type metal trifluorides with corner sharing matrix have large bottlenecks of diffusion pathways for intercalants. Iron trifluoride composites (FeF3-C) prepared by planetary ball milling with carbon showed reversible charge/discharge behavior not only for Li, but also for Na anodes. X-ray diffraction and 57Fe Mössbauer spectroscopy were applied to characterize the electrochemical properties of FeF3 vs. Li and Na anodes. The cathode performances of the other commercially available transition metal trifluorides such as MF3 (M = Ti, V, Mn, Co) have been also investigated. 相似文献