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71.
The local strains in Si pillars induced by SiN stressors were quantitatively investigated as a function of geometry by micro-Raman scattering spectroscopy. Raman shifts of a cantilever microstructure were twice as large as those of a bridge microstructure. This difference was due to the different dimensions of the strains, i.e., biaxial strains in the cantilever type and uniaxial strains in bridge type. The thermal stability of the SiN stressor was also investigated. The results showed induced strains were stable after post-annealing at high temperature (∼1000 °C). 相似文献
72.
Masuhiro Tsukada Masanobu Nagura Hiroshi Ishikawa 《Journal of Polymer Science.Polymer Physics》1987,25(6):1325-1329
Structural changes in poly(L -alanine)(PLA), a model compound related to tussah silk fibroin, induced by heat treatment have been studied by differential thermal analysis, x-ray diffraction, and infrared spectroscopy. PLA heated below 300°C shows x-ray patterns very similar to those of the α-helix crystalline phase, in addition to the diffraction patterns due to the β structure. Samples heated at 368°C exhibit predominantly the diffraction patterns due to the β crystalline phase. From infrared spectra, PLA samples heated below 280°C are found to be composed of all three molecular conformations: β sheet, random coil, and α helix. The intensity of the infrared absorption at 650 cm?1 (amide V) assigned to the random coil conformation is decreased by heat treatment above 325°C. The content of the β-sheet structure remains almost constant when the specimen is heated below 325°C, and increases abruptly on heating to around 335°C, while the random coil content is decreased abruptly by heat treatment above 335°C. The α-helix content does not change, regardless of heat treatment. It is suggested therefore that the random coil conformation of PLA transforms directly into the β sheet on heat treatment above 335°C. 相似文献
73.
Masanobu Yajima 《Tetrahedron letters》2009,50(33):4754-2495
The rearrangement of cyclopropylmagnesium carbenoids, which were generated from aryl 1-chlorocyclopropyl sulfoxides with a Grignard reagent, to allenes was found to be suppressed by adding HMPA as an additive. Alkylation of the cyclopropylmagnesium carbenoids with the Grignard reagent gives mainly alkylated cyclopropylmagnesium chloride instead. The cyclopropylmagnesium chloride intermediate can be trapped with several electrophiles to afford multi-substituted cyclopropanes. This procedure provides a new method for a synthesis of multi-substituted cyclopropanes. 相似文献
74.
Atsuya Muranaka Masaki Yokoyama Yotaro Matsumoto Masanobu Uchiyama Akihiko Tsuda Atsuhiro Osuka Nagao Kobayashi 《Chemphyschem》2005,6(1):171-179
The magnetic circular dichroism (MCD) spectra of doubly and triply linked fused bisporphyrins (2MD and 2MT, M = Ni, Zn, Cu, Pd, and H2) and triply linked higher oligomers (3ZnT and 4ZnT) have been measured, and their Q-bands assigned based on the results of INDO/s calculations. In contrast to the Faraday A term observed for the Q(0,0) band of Ni(II) tetraphenylporphyrin, a single positive Faraday B term was observed for the lowest energy transition of the fused systems. The calculations indicated that the molecular orbitals (MOs) of the directly fused porphyrins consist of linear combinations of the constituent monomeric MOs, and that the effect of lowering the symmetry is always larger on the lowest unoccupied molecular orbital (LUMO) than on the highest occupied molecular orbital (HOMO). On the basis of Michl's perimeter model, these features can be correlated with the observed positive MCD signs in the near infrared region. A weak absorption band at 600-700 nm for the fused dimers can be assigned to a short-axis polarized Q transition. 相似文献
75.
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77.
Naoki Fujita Takayuki Makino Yasuhiro Sakoishi Katsuya Asano Masanobu Kusunoki 《Crystal Research and Technology》2016,51(3):215-219
The relation between O2 pressure and composition in the pulsed‐laser deposition of fluoroapatite was investigated using both on‐axis and off‐axis methods to determine the optimal conditions for obtaining a pure fluoroapatite film without OH groups. Through this, it was found that an O2 pressure of 10 Pa, combined with an off‐axis method, results in P/Ca and F/Ca values (0.6 and 0.2, respectively) that match closely with a stoichiometric composition of Ca10(PO4)6F2. Fourier transform infrared spectroscopy analysis confirmed that this optimized film was almost pure fluoroapatite, with no evidence of any OH groups originating from hydroxyapatite. X‐ray diffraction also revealed that this fluoroapatite film crystallizes with a c‐axis orientation perpendicular to its surface. 相似文献
78.
Dr. Nguyet Trang Thanh Chau Maxime Meyer Dr. Shinsuke Komagawa Dr. Floris Chevallier Prof. Yves Fort Prof. Masanobu Uchiyama Prof. Florence Mongin Dr. Philippe C. Gros 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(41):12425-12433
Homoleptic lithium tri‐ and tetraalkyl zincates were reacted with a set of bromopyridines. Efficient and chemoselective bromine–metal exchanges were realized at room temperature with a substoichiometric amount of nBu4ZnLi2?TMEDA reagent (1/3 equiv; TMEDA=N,N,N′,N′‐tetramethylethylenediamine). This reactivity contrasted with that of tBu4ZnLi2?TMEDA, which was inefficient below one equivalent. DFT calculations allowed us to rationalize the formation of N???Li stabilized polypyridyl zincates in the reaction. The one‐pot difunctionalization of dibromopyridines was also realized using the reagent stoichiometrically. The direct creation of C? Zn bonds in bromopyridines enabled us to perform efficient Negishi‐type cross‐couplings. 相似文献
79.
We investigated the insertion and return losses of optical fiber connections with various air-filled gaps. Such gaps might occur when a fiber connection using physical contact unexpectedly fails, resulting in imperfect physical contact. The optical performance of these fiber connections depends on wavelength and gap size. We revealed that the measured optical performance of fiber connections with an imperfect physical contact, i.e., with an air-filled gap, might deteriorate to ~18 dB for insertion loss and 9.4 dB for return loss at worst. 相似文献
80.
Takashi Nakanishi Masanobu Naito Yukikazu Takeoka Kazunori Matsuura 《Current Opinion in Colloid & Interface Science》2011,16(6):482-490
In this review article, we describe recent progress about exotic self-assembled systems with various dimensions including biomolecules, supramolecules, unique hydrophobic amphiphiles, polymers, nano-clusters, and colloidal particles. Construction of robust biomolecular assemblies with exotic structures, such as ring and hollow capsule, is achieved by rational designs of symmetric biomolecular conjugates. In addition, we comprehensively summarized leading-edge topics on optical/topological properties of self-assembled hybrid systems, such as circularly polarized luminescence or structural color. The preparation of colloidal amorphous array with photonic band gap-induced angle-independent structural color is also achieved in consideration of the following situations: i) two-body sphere–sphere potential, ii) disorder packing using different sizes of colloidal particles, and iii) softness of colloidal particles. Lastly, we demonstrated useful utilizations of exotic self-assembled objects. Flakelike microparticles were transcribed into various nano-flake metals and applied as temperature indicator for the local heating of an addictive. All findings described here show meaningful hybrid strategies in self-assembly techniques and their functionalization as well as materialization. 相似文献