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141.
Chifei Wu Tada‐Aki Yamagishi Yoshiaki Nakamoto Shin‐Ichiro Ishida Koh‐Hei Nitta Saburo Kubota 《Journal of Polymer Science.Polymer Physics》2000,38(10):1341-1347
The dynamic mechanical properties of an organic hybrid consisting of chlorinated polyethylene (CPE) and N,N‐dicyclohexyl‐2‐benzothiazolyl sulfenamide (DZ) were investigated. All the CPE/DZ hybrids showed a single loss tangent (tan δ) peak in the mechanical spectra. The peak area under the tan δ/temperature curves around the mechanical loss peak was examined to characterize the damping properties of the CPE/DZ hybrids. We found that there exists a bending point in the relation between the glass‐transition temperature (Tg) and DZ content and that the value of Tg is saturated in the higher DZ contents, suggesting that excess DZ molecules show self‐aggregation and are reorganized. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1341–1347, 2000 相似文献
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143.
在线性压电陶瓷本构关系和裂纹边界绝缘的框架下,用超奇异积分方程的方法对椭圆类片状裂纹问题进行了重新研究.超奇异积分方程中的未知位移间断和电势间断近似地表示为基本密度函数与多项式之积,其中基本密度函数反映了椭圆片状裂纹前沿电弹性场的奇异性,而多项式在均布载荷作用下可用一个常数来表达.引入椭球坐标系后,得到了均布载荷作用下未知位移间断和电势间断的解析解.使用这些解析解和电弹性场强度的定义,得到了裂纹前沿Ⅰ型、Ⅱ型和Ⅲ型应力强度因子以及电位移强度因子的精确表达式.法向均布载荷作用下的结果与现有精确解完全一致,切向均布载荷作用下的结果则尚未见有其它报道. 相似文献
144.
Yoshio Imai Kazuo Itoya Masami Kanamaru Masa‐Aki Kakimoto 《Journal of polymer science. Part A, Polymer chemistry》2002,40(11):1790-1795
New phenolic hydroxyl‐pendant aromatic polyimides were synthesized with the N‐silylated diamine method in two steps: the ring‐opening polyaddition of tetrakis(trimethylsilyl)‐substituted 4,4′‐diamino‐3,3′‐dihydroxybiphenyl to various aromatic tetracarboxylic dianhydrides, giving trimethylsiloxy‐pendant poly(amic acid) trimethylsilyl esters, and thermal imidization. The hydroxyl‐bearing polyimides were amorphous but insoluble in organic solvents. They had glass‐transition temperatures greater than 370 °C and temperatures of 10% weight loss greater than 415 °C in nitrogen. The hydroxyl‐pendant polypyromellitimide film had a high tensile strength and a high modulus of 310 MPa and 10 GPa, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1790–1795, 2002 相似文献
145.
Annals of the Institute of Statistical Mathematics - Let k be a positive integer. Some exact distributions of the waiting time random variables for k consecutive repetitions of a pattern are... 相似文献
146.
147.
Yasuyuki Miyoshi Takeo Akatsuka Shin‐ichi Okuoka Aki Tsukajima Mitsuaki Makino Makoto Saito Dr. Koji Yonehara 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(25):7941-7949
Further study of our aerobic intermolecular cyclization of acrylic acid with 1‐octene to afford α‐methylene‐γ‐butyrolactones, catalyzed by the Pd(OCOCF3)2/Cu(OAc)2 ? H2O system, has clarified that the accumulation of water generated from oxygen during the reaction causes deactivation of the Cu cocatalyst. This prevents regeneration of the active Pd catalyst and, thus, has a harmful influence on the progress of the cyclization. As a result, both the substrate conversion and product yield are efficiently improved by continuous removal of water from the reaction mixture. Detailed analysis of the kinetic and spectroscopic measurements performed under the condition of continuous water removal demonstrates that the cyclization proceeds in four steps: 1) equilibrium coordination of 1‐octene to the Pd acrylate species, 2) Markovnikov‐type acryloxy palladation of 1‐octene (1,2‐addition), 3) intramolecular carbopalladation, and 4) β‐hydride elimination. Byproduct 2‐acryloxy‐1‐octene is formed by β‐hydride elimination after step 2). These cyclization steps fit the Michaelis–Menten equation well and β‐hydride elimination is considered to be a rate‐limiting step in the formation of the products. Spectroscopic data agree sufficiently with the existence of the intermediates bearing acrylate (Pd? O bond), η3‐C8H15 (Pd? C bond), or C11H19O2 (Pd? C bond) moieties on the Pd center as the resting‐state compounds. Furthermore, not only CuII, but also CuI, species are observed during the reaction time of 2–8 h when the reaction proceeds efficiently. This result suggests that the CuII species is partially reduced to the CuI species when the active Pd catalytic species are regenerated. 相似文献
148.
Sigeo Aki 《Annals of the Institute of Statistical Mathematics》2012,64(3):633-655
This paper proposes a new method for constructing a sequence of infinitely exchangeable uniform random variables on the unit
interval. For constructing the sequence, we utilize a Pólya urn partially. The resulting exchangeable sequence depends on
the initial numbers of balls of the Pólya urn. We also derive the de Finetti measure for the exchangeable sequence. For an
arbitrarily given one-dimensional distribution function, we generate sequences of exchangeable random variables with the one-dimensional
marginal distribution by transforming the exchangeable uniform sequences with the inverse function of the distribution function.
Among them we mainly investigate sequences of exchangeable discrete random variables. They differ from the well-known exchangeable
sequence generated only by the Pólya urn scheme. Some examples are also given as applications of the results to exact distributions
of some statistics based on sequences of exchangeable trials. Further, from the above exchangeable uniform sequence we construct
partial or Markov exchangeable sequences. We also provide numerical examples of statistical inference based on the exchangeable
and Markov exchangeable sequences. 相似文献
149.
Mibu N Yokomizo K Uchida W Takemura S Zhou J Aki H Miyata T Sumoto K 《Chemical & pharmaceutical bulletin》2012,60(3):408-414
In terms of molecular symmetry and bioactivity, new C3- and CS-symmetrical derivatives based on the tris(2-aminoethyl)amine scaffold were designed and synthesized. The synthesized compounds were evaluated for antiviral activity with herpes simplex virus type 1 (HSV-1) by a plaque reduction assay and for cytotoxic activity with Vero cells. Most of the compounds showed no significant anti-HSV-1 activity, but some of the symmetrical derivatives showed high levels of cytotoxic activitiy. 相似文献
150.
Bozorgmehri Babak Yu Xinxin Matikainen Marko K. Harish Ajay B. Mikkola Aki 《Nonlinear dynamics》2021,103(1):581-616
Nonlinear Dynamics - This paper introduces a procedure in the field of computational contact mechanics to analyze contact dynamics of beams undergoing large overall motion with large deformations... 相似文献