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981.
Takeya S Yoneyama A Miyamoto J Gotoh Y Ueda K Hyodo K Takeda T 《Journal of synchrotron radiation》2010,17(6):813-816
The understanding of and in situ observation of the transport and distribution of water in carbon‐paper gas diffusion layers (GDLs) using non‐destructive imaging techniques is critical for achieving high performance in polymer electrolyte fuel cells (PEFCs). To investigate the behavior of water in GDLs of PEFCs, phase‐contrast X‐ray imaging via X‐ray interferometric imaging (XII) and diffraction‐enhanced imaging (DEI) were performed using 35 keV X‐rays. The XII technique is useful for the radiographic imaging of GDLs and in situ observations of water evolution processes in operating PEFCs. DEI provides a way for tomographic imaging of GDLs in PEFCs. Because high‐energy X‐rays are applicable to the imaging of both carbon papers and heavy materials, which make up PEFCs, phase‐contrast X‐ray imaging techniques have proven to be valuable for investigation of GDLs. 相似文献
982.
The modal characteristics of localized electromagnetic waves inside random nanostructures are theoretically presented. It is crucial to know the tuneabilities of the localized modes systematically for demonstrating a specific random lasing application. By use of FDTD (Finite-Difference Time-Domain) method, we investigated the impulse response of two-dimensional random nanostructures consisting of closely packed cylindrical dielectric columns, and precisely analyzed the localized modes. We revealed the tuneability of the frequency of the localized modes by controlling the medium configurations: diameter, spatial density, and refractive index of the cylinders. Furthermore, it is found to be able to tune the Q (quality) factors of the localized modes dramatically by controlling simply the system size of the entire medium. The observed Q factors of approximately 1.6×104 were exhibited in our random disordered structures. 相似文献
983.
Abstract
Interfacial waves of two immiscible layers in a spin-up container were investigated using experimental visualization. While the interface near the central part rose up, instability waves propagated in an azimuthal direction on the interface. These waves were mainly caused by Kelvin–Helmholtz instability for the velocity difference between two layers during spin-up, but had complicated transient characteristics owing to the rotation in a closed system. We visualized the structure of the interfacial waves by the use of three types of optical characteristics of the interface. Image processing provided the detailed factors of the interfacial waves that were classified in four life stages from their generation to disappearance. The initial generation process involved many frequency modes due to a large velocity difference, and then a low mode stood out during the growth, and disappeared with an ellipsoidal sloshing mode to achieve the rigid rotation in both layers. 相似文献984.
Akiko Takeda Shunsuke Taguchi Tsutomu Tanaka 《Computational Optimization and Applications》2010,47(1):1-31
Three measures of robustness (absolute robustness, deviation robustness and relative robustness), whose choice depends on
the goals of the decision maker, have been proposed for uncertain optimization problems. Absolute robustness has been thoroughly
studied, whereas the others have been studied to less of a degree. 相似文献
985.
Takayuki Oku Takayuki Kikuchi Takenao Shinohara Jun-ichi Suzuki Yuya Ishii Masayasu Takeda Kazuhisa Kakurai Yuji Sasaki Mikio Kishimoto Makoto Yokoyama Yoshikazu Nishihara 《Physica B: Condensed Matter》2009,404(17):2575-2577
We have performed small-angle polarized neutron scattering experiments of spherical Fe16N2 nano-particles, which are potential candidate materials for high density magnetic recording tape. The results were analyzed based on a core-shell model, and we evaluated the magnetic structure of the particles. The correlation between the magnetic structure and magnetic stability of the particles were discussed in terms of high density recordings. 相似文献
986.
Cover Picture: Enantioselective Addition of a 2‐Alkoxycarbonyl‐1,3‐dithiane to Imines Catalyzed by a Bis(guanidino)iminophosphorane Organosuperbase (Angew. Chem. Int. Ed. 52/2015) 下载免费PDF全文
987.
Revisiting Phosphorus Analogues of Phthalimides and Naphthalimides: Syntheses and Comparative Studies 下载免费PDF全文
Dr. Youhei Takeda Takuya Nishida Kota Hatanaka Prof. Dr. Satoshi Minakata 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1666-1672
A series of phosphorus analogues of aromatic‐fused monoimides (phthalimides and naphthalimides) bearing a mesityl group on the P center have been synthesized. In a comparison of their photophysical, electrochemical, and thermal properties with those of the corresponding imides, the impact of P incorporation was revealed. Furthermore, theoretical studies using DFT methods were conducted to understand their properties. 相似文献
988.
Anisotropic Dissociation of π–π Stacking and Flipping‐Motion‐Induced Crystal Jumping in Alkylacridones and Their Dicyanomethylene Derivatives 下载免费PDF全文
Dr. Takashi Takeda Prof. Tomoyuki Akutagawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(23):7763-7770
Ethylacridone ( 1 b ) and dicyanomethylenated acridones 2 a , b , d showed crystal‐jumping activity upon heating. This is the first example of thermosalient behavior in a simple aromatic ketone and its derivatives. A systematic investigation of the jumping behavior of derivatives with different alkyl chains by variable‐temperature X‐ray crystal‐structure analyses revealed the mechanism of this phenomenon. Anisotropic dissociation of π stacking in a dimer was important for inducing crystal jumping in 1 b , whereas the collective fluctuation/flipping motion of a dicyanomethylene unit induced crystal jumping in 2 . 相似文献
989.
990.
Synthesis of quinoline derivatives by Lewis acid catalyzed [4+2]cycloaddition was investigated. 相似文献