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851.
Rheological properties of poly(methyl methacrylate)/rigid ladderlike polyphenylsilsesquioxane blends
Guizhi Li T. Matsuda A. Nishioka Kaiwen Liang Y. Masubuchi K. Koyama Charles U. Pittman Jr. 《应用聚合物科学杂志》2007,104(1):352-359
A series of poly(methyl methacrylate) (PMMA) blends with rigid ladderlike polyphenylsilsesquioxane (PPSQ) were prepared at weight ratios of 100/0, 95/5, 90/10, 85/15, and 80/20 by solution casting and then hot‐pressing. Their rheological properties have been studied under both dynamic shear and uniaxial elongation conditions. Their rheological properties depend on the compositions. The storage modulus, G′, loss modulus, G″, and dynamic shear viscosity, η*, of the PMMA/PPSQ 95/5 blend were slightly lower than those of pure PMMA. However, the values of G′, G″, and η* for the other PMMA/PPSQ blends are higher than those of PMMA. The G′ values increase with an increase in PPSQ content from 5% through 15% PPSQ at low frequencies and then drop as the PPSQ content increases to 20%. Uniaxial elongational viscosity (ηE) data demonstrate that PMMA/PPSQ blends exhibit slightly weaker (5% PPSQ) and much weaker (10% PPSQ) strain‐hardening than PMMA. In contrast, the PMMA/PPSQ 85/15 blend shows strain‐softening. Neither strain‐hardening nor strain‐softening was observed in the 80/20 blend. The special rheological properties for the 95/5 blend is probably due to a decrease in PMMA entanglements brought by the specific PMMA–PPSQ interactions. Rheological properties of PMMA/PPSQ blends with higher PPSQ content (≥10%) are mainly affected by formation of hard PPSQ particles. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 352–359, 2007 相似文献
852.
Tensile tests are carried out by using rectangular plate specimens extracted from the explosion clad plate. Artificial parallel cracks are made perpendicularly to the explosive interface in each specimen. When a tensile load is applied perpendicularly to the crack plane, strain, plastic deformation near cracks and crack opening displacement are examined by experiments as well as elasto-plastic finite element analysis. The effects of the material inhomogeneity, the change of material characteristics, the residual stress and the interaction between parallel cracks on the deformation behavior are revealed. The plastic zone around parallel cracks, at relatively low applied stress level, grows mainly ahead of and between two cracks. The interaction between parallel cracks on the crack opening displacement can be explained from the square of stress intensity factor at the low applied stress level and from the plastic deformation at the high applied stress level. 相似文献
853.
854.
Akihide Kuwabara Xiang Gao Ralf Riedel Emanuel Ionescu Yuichi Ikuhara 《International Journal of Applied Ceramic Technology》2023,20(1):190-196
Transition-metal-doped silicon nitride ceramics have attracted much attention as gate materials for semiconductors because of their electrical properties as well as chemical and thermal stability. The present study aims to clarify the defect structures of Hf-doped β-Si3N4 by theoretical calculations and scanning transmission electron microscopy (STEM). First-principles calculations based on a hybrid functional method were performed. It was found that Hf dopants are mainly substituted for the Si sites and can be occasionally located at interstitial sites in the lattice of β-Si3N4. The substitution sites of Hf dopants predicted by the first-principles calculations were also confirmed by the high-resolution STEM images. 相似文献
855.
Daichi Yazaki Tokuhisa Kawawaki Daisuke Hirayama Masanobu Kawachi Kosaku Kato Sota Oguchi Yuichi Yamaguchi Soichi Kikkawa Yoshiya Ueki Sakiat Hossain D. J. Osborn Fumihiko Ozaki Shunsuke Tanaka Jun Yoshinobu Gregory F. Metha Seiji Yamazoe Akihiko Kudo Akira Yamakata Yuichi Negishi 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(34):2208287
For the realization of a next-generation energy society, further improvement in the activity of water-splitting photocatalysts is essential. Platinum (Pt) is predicted to be the most effective cocatalyst for hydrogen evolution from water. However, when the number of active sites is increased by decreasing the particle size, the Pt cocatalyst is easily oxidized and thereby loses its activity. In this study, a method to load ultrafine, monodisperse, metallic Pt nanoclusters (NCs) on graphitic carbon nitride is developed, which is a promising visible-light-driven photocatalyst. In this photocatalyst, a part of the surface of the Pt NCs is protected by sulfur atoms, preventing oxidation. Consequently, the hydrogen-evolution activity per loading weight of Pt cocatalyst is significantly improved, 53 times, compared with that of a Pt-cocatalyst loaded photocatalyst by the conventional method. The developed method is also effective to enhance the overall water-splitting activity of other advanced photocatalysts such as SrTiO3 and BaLa4Ti4O15. 相似文献
856.
Artificial Life and Robotics - An operator feels a burden when he/she controls a rescue robot remotely because he/she has to keep watching camera images to find the target object. We think that... 相似文献
857.
Kenta Hanada Takayuki Wada Izumi Masubuchi Toru Asai Yasumasa Fujisaki 《Asian journal of control》2023,25(2):651-661
A multi-agent consensus protocol is investigated over noisy undirected connected graphs. It is supposed that each agent can know her neighbors' states with bounded noise. A theoretical stopping rule having a probabilistic guarantee is established for the consensus protocol, which explicitly relates the number of iterations with the closeness of the agreement. The stopping rule is derived by utilizing Bernstein inequality that deals with a given noise bound explicitly. The sample complexity with respect to the number of agents is also investigated, where it is shown that the number of iterations required by the proposed stopping rule based on the bound of noise itself is generally smaller than that of the conventional stopping rules that utilize bound of noise variance. The results are demonstrated through numerical examples. 相似文献
858.
Masaya Tanemura Yuichi Chida Shohei Terada Tomoharu Iida 《Asian journal of control》2023,25(2):783-793
In this study, we considered the regulator problem for discrete-valued input control with an integrator. In some cases, the state does not converge to the origin in the discrete-valued input control when the plant possesses an integrator. Therefore, a method that adds minor feedback control to the integrated value of the input was proposed. However, the effect of the feedback control of the integrated value of the input was not theoretically interpreted, and the feedback gain for the state of the integrated value of the input was designed with trial and error. Herein, we clarify the effect of feedback control on the integrated value of the input. Furthermore, we reveal that the trade-off between the steady-state and transient performances is controlled by one parameter, that is, the feedback gain for the integrated value of the input. 相似文献
859.
Ryo Ishikawa Naoya Shibata Fumiyasu Oba Takashi Taniguchi Yuichi Ikuhara 《International Journal of Applied Ceramic Technology》2023,20(1):166-173
Wide bandgap III-nitrides, such as cubic boron nitride and wurtzite-type aluminum nitride, are promising systems for optoelectronics. To extend their luminescent properties, we doped single Ce atoms into III-nitride single crystals using reactive flux with a temperature gradient method at high-pressure and high-temperature conditions. To fully understand such properties in a large size-mismatch system, it is critically important to determine the point-defect structures of single dopants, their spatial distribution in three dimensions, and their atomistic dynamics at an atomic level. This review discusses point defect structures and their dynamics in III-nitrides using single-atom-sensitive scanning transmission electron microscopy, and the recent progress in the related field of electron microscopy. 相似文献