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141.
Patrick Nickels Takeji Ueda Zhenghua An Susumu Komiyama 《Infrared Physics & Technology》2009,52(6):438-441
A novel highly sensitive detector for long wavelength infrared radiation, called charge sensitive infrared phototransistor (CSIP), is described, with a stress put on the report of recent improvements in the quantum efficiency. Metallic antenna structure placed on the surface to convert incident radiation has to be optimized. In case of the CSIP, where the absorbing quantum well is very close (~100 nm) to the antenna, near field effects have to be taken into consideration. We consider several patterns based either on a double capacitive (dot) or inductive (hole) grating. We present results of a study comparing four different geometries showing that cross shape hole arrays are most promising candidates reaching efficiencies of almost 8%. Further strategies to optimize essential parameters of antennas by using finite difference time domain (FDTD) simulations are considered. 相似文献
142.
143.
Hiraoka S Okamoto T Kozaki M Shiomi D Sato K Takui T Okada K 《Journal of the American Chemical Society》2004,126(1):58-59
A stable radical-substituted radical ion with strongly ferromagnetic intramolecular interaction (J) between the radical and radical ion sites is an attractive spin building block of organic magnets. We prepared 2-nitronyl nitroxide-substituted 5,10-diphenyl-5,10-dihydrophenazine radical cation, 1+. The 1+ salt was stable under aerated conditions at room temperature and had a large J/kB value (>/=+700 K). 相似文献
144.
Takeji Hashimoto Yukinobu Murakami Hiromichi Kawai 《Journal of Polymer Science.Polymer Physics》1975,13(8):1613-1631
The light scattering intensity distribution from rodlike crystalline superstructures is quantitatively investigated theoretically and experimentally. The arithmetic average of theoretical Hv scattered intensities at azimuthal angle μ = 0° and μ = 45° is shown to decrease with increasing scattering angle θ in proportion to W?1 at high scattering angles for a system composed of a random assembly of rodlike superstructure having very small lateral dimensions relative to the length. The quantity W is defined as 2π(L/λ) sin θ where L is the length of the rod, and λ is the wavelength of light in the medium. A method is proposed to estimate the length L by using the W?1 dependence. Effects of internal heterogenity, polydispersity in rod length, and finite lateral dimensions of the rodlike superstructure are considered to account for experimental deviation of the scattered intensity distributions from the W?1 dependence. The effect of finite lateral dimensions turns out to be the most important. 相似文献
145.
Dr. Masaru Fujibayashi Yu Watari Dr. Ryo Tsunashima Prof. Sadafumi Nishihara Prof. Shin-ichiro Noro Dr. Chang-Gen Lin Prof. Yu-Fei Song Dr. Kiyonori Takahashi Prof. Takayoshi Nakamura Prof. Tomoyuki Akutagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(50):22632-22636
The structural phase of a metal oxide changes with temperature and pressure. During phase transitions, component ions move in multidimensional metal–oxygen networks. Such macroscopic structural events are robust to changes in particle size, even at scales of around 10 nm, and size effects limiting these transitions are particularly important in, for example, high-density memory applications of ferroelectrics. In this study, we examined structural transitions of the molecular metal oxide [Na@(SO3)2(n-BuPO3)4MoV4MoVI14O49]5− (Molecule 1 ) at approximately 2 nm by using single-crystal X-ray diffraction analysis. The Na+ encapsulated in the discrete metal-oxide anion exhibited a reversible order–disorder transition with distortion of the Mo–O molecular framework induced by temperature. Similar order–disorder transitions were also triggered by chemical pressure induced by removing crystalline solvent molecules in the single-crystal state or by substituting the countercation to change the molecular packing. 相似文献
146.
Dr. Shinsuke Nishida Dr. Junya Kawai Miki Moriguchi Tomohiro Ohba Naoki Haneda Dr. Kozo Fukui Prof. Akira Fuyuhiro Prof. Daisuke Shiomi Prof. Kazunobu Sato Prof. Takeji Takui Prof. Kazuhiro Nakasuji Prof. Yasushi Morita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(36):11904-11915
The tri‐tert‐butylphenalenyl (TBPLY) radical exists as a π dimer in the crystal form with perfect overlapping of the singly occupied molecular orbitals (SOMOs) causing strong antiferromagnetic exchange interactions. 2,5‐Di‐tert‐butyl‐6‐oxophenalenoxyl (6OPO) is a phenalenyl‐based air‐stable neutral π radical with extensive spin delocalization and is a counter analogue of phenalenyl in terms of the topological symmetry of the spin density distribution. X‐ray crystal structure analyses showed that 8‐tert‐butyl‐ and 8‐(p‐XC6H4)‐6OPOs (X=I, Br) also form π dimers in the crystalline state. The π‐dimeric structure of 8‐tert‐butyl‐6OPO is seemingly similar to that of TBPLY even though its SOMO–SOMO overlap is small compared with that of TBPLY. The 8‐(p‐XC6H4) derivatives form slipped stacking π dimers in which the SOMO–SOMO overlaps are greater than in 8‐tert‐butyl‐6OPO, but still smaller than in TBPLY. The solid‐state electronic spectra of the 6OPO derivatives show much weaker intradimer charge‐transfer bands, and SQUID measurements for 8‐(p‐BrC6H4)‐6OPO show a weak antiferromagnetic exchange interaction in the π dimer. These results demonstrate that the control of the spin distribution patterns of the phenalenyl skeleton switches the mode of exchange interaction within the phenalenyl‐based π dimer. The formation of the relevant multicenter–two‐electron bonds is discussed. 相似文献
147.
148.
Teruaki Koto Kenji Sugisaki Kazunobu Sato Daisuke Shiomi Kazuo Toyota Koichi Itoh Edel Wasserman Paul M. Lahti Takeji Takui 《Applied magnetic resonance》2010,37(1-4):703-736
In high-spin chemistry, random-orientation fine-structure electron paramagnetic resonance (FS ESR) spectroscopy holds the advantages of the most facile and convenient method to identify high-spin systems. The FS ESR spectroscopy for high spins in frozen rigid glasses has seemingly been well established since the first spin-quintet m-dicarbene and m-dinitrene appeared in 1967. The FS ESR spectra of organic quintet entities generated by photolysis in the 2-methyltetrahydrofuran (2-MTHF) glass, however, have never been fully analyzed due to a peculiar line broadening appearing at many canonical peaks. The line broadening has been a notorious obstacle that masks key FS transitions of many cases in organic glasses or argon matrices. We examine the origin of the line broadening, illustrating the comprehensive spectral analysis for m-dinitrenes and other types of typical quintet-state dinitrenes observed in the 2-MTHF glass. Our new approach to the line broadening analysis invokes both exact analytical solutions for the resonance fields of canonical peaks and a magnetic-parameter gradient method. We have derived the exact analytical expressions for FS canonical peaks for high-spin states, for the first time. A microscopic origin of the line broadening observed for high-spin nitrenes generated by photolysis in rigid glasses is proposed on the basis of quantum chemical calculations of the D-tensor. 相似文献
149.
150.
Hiroki Murase Takuji Kume Takeji Hashimoto Yasuo Ohta Tohru Mizukami 《Macromolecular Symposia》1996,104(1):159-182
The shear-induced concentration fluctuations or phase separation of a semidilute solution comprised of polystyrene (PS) as a solute and dioctylphthalate (DOP) as a solvent (PS/DOP) was investigated by using real-time and in-situ shear-small-angle light scattering and shear-phase-contrast optical microscopy. When a transient shear flow with a fixed shear rate γ greater than a critical value γC was imposed on the solution, a unique anisotropic scattering pattern was observed some time after onset of shear. This pattern was found to be identical to the “butterfly pattern” previously reported for the same solutions under steady shear flow with γC. When the shear flow was ceased before the scattered intensity reached a steady state, the scattered intensity rapidly increased toward a maximum intensity, and then decreased toward the intensity of the quiescent solution with time. From the phase-contrast microscopy, this immediate increment of the scattered intensity after the shear cessation was found to arise from the increment in amplitude of the concentration fluctuations along flow direction. The characteristic length scale of the fluctuations was about 2.5 μm in this experiment, almost independent of the shear rate imposed on the solution. 相似文献