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排序方式: 共有118条查询结果,搜索用时 15 毫秒
31.
T. Watanabe M. Miyagi S. Schrunder T. Ertl G. Müller L Beerstecher 《Optics & Laser Technology》1995,27(6):389-391
A maximum energy of 1.6 J at 5 pps of Er:YAG laser light has been transmitted through a flexible ZnS-coated silver hollow waveguide which has an inner diameter of 800 μm and is 116 cm long. The straight waveguide loss is 0.6 dB m−1 and no significant loss and mechanical changes have been found after an endurance test of 10000 pulse transmissions and bending 400 times with a bending radius of 30 cm. 相似文献
32.
Toshiko Watanabe Chiemi Miyagi Yasuoki Murakami 《Journal of heterocyclic chemistry》1993,30(1):217-224
To confirm the structure of ethyl 9-methoxybenz[f]indole ( 8a ) prepared from ethyl pyrrole-2-carboxylate ( 4 ) via a new synthetic route, the following chemical correlation work was performed. Ethyl 9-methoxybenz[f]in-dole ( 8a ) was converted to 1-benzyl-3-methyl-5,6,7,8-tetrahydrobenz[f]indole ( 25 ), which was alternatively and authentically synthesized from ethyl 3-methylpyrrole-2-carboxylate ( 11 ). On the basis of the established route to the benz[f]indole nucleus, two representative benz[f]indoles, benz[f]indole ( 1 ) and 4,9-dioxobenz[f]indole ( 26 ) were synthesized. 相似文献
33.
Dr. Hiromitsu Sogawa Dr. Kayo Terada Yu Miyagi Prof. Dr. Masashi Shiotsuki Prof. Dr. Yoshihito Inai Prof. Dr. Toshio Masuda Prof. Dr. Fumio Sanda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(18):6747-6755
A series of new photo‐responsive amino acid‐derived azobenzenedicarboxylic acid derivatives (S)‐ 1 a – e were synthesized. Compound (S)‐ 1 a in the trans form exhibited no circular dichroism (CD) signal in DMF under ambient conditions, whereas intense Cotton effects were observed upon UV irradiation, indicating the formation of a chiral supramolecular structure in the cis form. The CD signals disappeared when trifluoroacetic acid (TFA) was added to the solution. The ester counterpart [(S)‐ 1 a′ ] showed no CD signal. Hydrogen bonding between the carboxy groups seemed necessary for constructing the supramolecular structure. The kinetic studies of cis to trans isomerization of (S)‐ 1 a demonstrated that the formation of a chiral supramolecule enhances the stability of the cis‐azobenzene structure. The ESI mass spectrum of stilbenedicarboxylic acid (S)‐ 4 , an analogue of (S)‐ 1 b , confirmed the formation of a dimer. A theoretical CD study revealed that (S)‐ 1 a in the cis form should be present as a cyclic chiral dimer. 相似文献
34.
Synthesis of optically active conjugated polymers containing platinum in the main chain: Control of the higher‐order structures by substituents and solvents
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Yu Miyagi Takehiro Hirao Takeharu Haino Fumio Sanda 《Journal of polymer science. Part A, Polymer chemistry》2015,53(21):2452-2461
The Sonogashira–Hagihara coupling polymerization of d ‐hydroxyphenylglycine‐derived diiodo monomers 1–4 and platinum‐containing diethynyl monomer 5 gave the corresponding polymers [poly( 1–5 )–( 2–5 )] with number‐average molecular weights of 19,000–25,000 quantitatively. The polymers were soluble in CHCl3, CH2Cl2, THF, and DMF. CD and UV–vis spectroscopic analysis revealed that amide‐substituted polymers [poly( 1–5 ) and poly( 2–5 )] formed chiral higher‐order structures in solution, while ester‐substituted polymers [poly( 3–5 ) and poly( 4–5 )] did not. Poly( 1–5 ) formed one‐handed helices in THF/toluene mixtures, while it formed chiral aggregates in THF/MeOH mixtures. Poly( 1–5 ) emitted fluorescence with quantum yields ranging from 0.8 to 1.3%. The polymers usually aggregated in the solid state. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 2452–2461 相似文献
35.
In order to achieve high-density recording, the detailed behavior of thermal degradation should be investigated. In this paper, the degradation of magnetization of high-density recording medium is examined using the 3-D finite element method (FEM) combined with the modeling of Stoner–Wohlfarth (SW) particles and Neel–Arrhenius switching probability. It is shown that the anisotropy field Hk suppressed the thermal degradation and the saturation magnetization Ms enhances it. The thermal degradation is also changed by the amplitude of magnetization. 相似文献
36.
37.
Hatsuo Yamamura Yuichi Yamada Rie Miyagi Kazuaki Kano Shuki Araki Masao Kawai 《Journal of inclusion phenomena and macrocyclic chemistry》2003,45(3-4):211-216
Three isomers of -cyclodextrin derivatives 2a–c possessing two trimethylammonio groups on their C(6) atoms were prepared by reaction of the corresponding regioisomers of diamino compounds with methyl iodide. These derivatives recognize chiral guests through three-point interactions composed of both Coulomb interactions by the two cationic moieties and hydrophobic interaction by the molecularcavity. 相似文献
38.
Sieber F Daziano JP Günther WH Krieg M Miyagi K Sampson RW Ostrowski MD Anderson GS Tsujino I Bula RJ 《Phosphorus, sulfur, and silicon and the related elements》2005,180(3-4):647-657
Elemental selenium generated by the photobleaching of selenomerocyanine dyes forms conjugates with serum albumin and serum lipoproteins that are toxic to leukemia and selected solid tumor cells but well tolerated by normal CD34-positive hematopoietic stem and progenitor cells. Serum albumin and lipoproteins act as Trojan horses that deliver the cytotoxic entity (elemental selenium) to tumor cells as part of a physiological process. They exploit the fact that many tumors have an increased demand for albumin and/or low-density lipoprotein. Se(0)-protein conjugates are more toxic than selenium dioxide, sodium selenite, selenomethionine, or selenocystine. They are only minimally affected by drug resistance mechanism, and they potentiate the cytotoxic effect of ionizing radiation and several standard chemotherapeutic agents. The cytotoxic mechanism of Se(0)-protein conjugates is not yet fully understood. Currently available data are consistent with the notion that Se(0)-protein conjugates act as air oxidation catalysts that cause a rapid depletion of intracellular glutathione and induce apoptosis. Drugs modeled after our Se(0)-protein conjugates may prove useful for the local and/or systemic therapy of cancer. 相似文献
39.
40.
Hideji Komatsu Ryoji Mogi Michio M. Matsushita Tadashi Miyagi Yuzo Kawada Tadashi Sugawara 《Polyhedron》2009,28(9-10):1996-2000
A novel organic donor radical, TSBN, which is a benzotetraselenafulvalene derivative carrying a nitronyl nitroxide group in a cross-conjugated manner was prepared. X-ray crystallographic analysis revealed that TSBN forms a sheet-like network within the ac plane through intermolecular chalcogen contacts. Its spin-polarized structure was confirmed by cyclic voltammogram, ESR spectra of singly oxidized species and DFT calculation. The neutral crystal of TSBN showed nonlinear I–V characteristics at 2 K and exhibited negative magnetoresistance (?5% at 2 K under 5 T). 相似文献