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排序方式: 共有169条查询结果,搜索用时 31 毫秒
41.
Dr. Shyamalendu M. Bose Tomoyasu Tanaka James Halow 《Zeitschrift für Physik B Condensed Matter》1973,16(4):319-326
The cluster variation method of the cooperative phenomena has been applied to the study of the theory of superconductivity.
The results obtained in this formulation are equivalent to the BCS results and follow in a straight forward and natural way
both at zero and finite temperatures. 相似文献
42.
43.
Motoki Yairi Kimihiro SakagamiEiji Sakagami Masayuki MorimotoAtsuo Minemura Kei Andow 《Applied Acoustics》2002,63(7):737-757
The sound radiation from a double-leaf elastic plate subjected to a point force excitation is investigated theoretically, to gain a fundamental insight into the sound radiation from an interior panel of a double-leaf structure in buildings. The effects of the interior panel on the sound radiation, which show a negative effect at low frequencies due to the mass-air-mass resonance, are discussed in detail. The theory is validated experimentally. As a measure of the efficiency of the interior leaf in reducing noise radiation, the radiation reduction is defined in this study, and it is found useful for predicting the sound radiation due to the structure-borne sound in building elements. Parametric studies through theoretical results are made to clarify the effects of the parameters of the sound radiation system, and to gain a fundamental insight into the control of structure-borne noise radiation. It is shown that it is difficult to reduce the radiated sound power by an interior panel alone, even if its mass is increased. 相似文献
44.
Hirose T Sunazuka T Shirahata T Yamamoto D Harigaya Y Kuwajima I Omura S 《Organic letters》2002,4(4):501-503
[reaction: see text] A short and efficient total synthesis of (+)-madindolines A (1) and B (2), potent and selective inhibitors of interleukin 6, has been achieved. The synthesis features a key chelation-controlled 1,4-diastereoselective acylation to generate the quaternary carbon and an intramolecular acylation of allylsilane to build up the cyclopentene unit. 相似文献
45.
Asymmetric Total Synthesis of Indole Alkaloids Containing an Indoline Spiroaminal Framework 下载免费PDF全文
Dr. Takeshi Yamada Dr. Tetsuya Ideguchi‐Matsushita Dr. Tomoyasu Hirose Dr. Tatsuya Shirahata Dr. Rei Hokari Dr. Aki Ishiyama Dr. Masato Iwatsuki Dr. Akihiro Sugawara Dr. Yoshinori Kobayashi Dr. Kazuhiko Otoguro Prof. Satoshi Ōmura Prof. Toshiaki Sunazuka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(33):11855-11864
The total synthesis of the indole alkaloids, neoxaline, oxaline and meleagrin A, all containing a unique indoline spiroaminal framework, was accomplished through the stereoselective introduction of a reverse prenyl group to the congested benzylic carbon of furoindoline, a two‐pot transformation of indoline (containing three nitrogen atoms at appropriate positions) to the featured indoline spiroaminal framework, and elimination of carbonate assisted by the adjacent imidazole moiety to construct the (E)‐dehydrohistidine. The absolute stereochemistry of neoxaline was elucidated through our total synthesis. In addition, we evaluated the bioactivity, especially the anti‐infectious properties, of neoxaline and oxaline, and of some synthetic intermediates. 相似文献
46.
The Design,Synthesis, and Evaluation of 1,5,7‐Trisubstituted‐3‐Pyridyl‐Xanthones for Use as Insecticides Starting from Pyripyropene A 下载免费PDF全文
Dr. Shinichiro Fuse Keisuke Matsumura Dr. Kohei Johmoto Dr. Hidehiro Uekusa Dr. Hiroshi Tanaka Dr. Tomoyasu Hirose Prof. Dr. Toshiaki Sunazuka Prof. Dr. Satoshi Ōmura Prof. Dr. Takashi Takahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18450-18455
A readily accessible template of 1,5,7‐trisubstituted‐3‐pyridyl‐xanthones was designed starting from naturally occurring pyripyropene A for agrichemical development. Our originally developed Ag2CO3‐mediated oxidative cyclization enabled ready access to the key scaffold, 1,5,7‐trihydroxy‐3‐chloro‐xanthone. The chemo‐ and regioselective sequential introduction of four substituents to the scaffold rapidly afforded the desired, structurally diverse 1,5,7‐trisubstituted‐3‐pyridyl‐xanthones. An evaluation of insecticidal activity revealed that one of the synthesized compounds retained insecticidal activity against vetch aphid and green peach aphid. The observed insecticidal spectrum was similar to that of pyripyropene A. The developed template could be a valuable aid for future agrichemical development. 相似文献
47.
New homologous series of N-[4-(4-n-alkoxybenzoyloxy)-2-hydroxybenzylidene]hydroxyanilines were synthesized. All 4-hydroxyaniline derivatives exhibited a nematic phase, while 3-hydroxyaniline and 2-hydroxyaniline derivatives exhibited only a nematic phase as the terminal alkoxy group was lengthened. Infrared spectra suggest that the 4-hydroxyaniline derivatives form intermolecular hydrogen bonding of the single bridge type, while the 3-hydroxy and 2-hydroxy derivatives form the polymer type. The Raman band at around 1360 cm-1 exhibited large differences in intensity among these derivatives. This can be explained by the effect of intermolecular or hydrogen bonding molecular conformation. 相似文献
48.
Tomoyasu Noji Masaharu Kondo Keisuke Kawakami Jian-Ren Shen Mamoru Nango Takehisa Dewa 《Research on Chemical Intermediates》2014,40(9):3231-3241
Photosystem II (PSII) has attracted a lot of attention for use in the construction of artificial photosynthetic materials due to its high activity of oxidation of water molecules. However, the robustness of PSII needs to be improved for in vitro application. In this study, we incorporated PSII (Thermosynechococcus vulcanus) into various phospholipid membranes to examine the activity and durability of oxygen evolution. PSII was incorporated into anionic 1,2-dioleoyl-sn-glycero-3-phospho-(1′-rac-glycerol) (PSII-DOPG), zwitterionic 1,2-dioleoyl-sn-glycero-3-phosphocholine (PSII-DOPC), and cationic 1,2-dioleoyl-sn-glycero-3-ethylphosphocholine (PSII-EDOPC). Structural integrity of PSII was examined by absorption and fluorescence spectroscopy. Compared with PSII dissolved in a micellar solution of n-dodecyl-β-d-maltoside (PSII-micelle), durability of PSII-DOPC and PSII-DOPG were enhanced by 1.3- and 1.5-fold, respectively. The activity and durability of PSII-EDOPC was significantly low. Lipid-dependent activity and durability were discussed in terms of kinetic parameters of V max and K m, and inhibition of the electron acceptor, phenyl-p-benzoquinone. 相似文献
49.
A liquid crystalline physical gel has been prepared from the mixture of a nematic liquid crystal and a low molecular mass gelling agent containing a hydrogen-bonding moiety. The newly synthesized liquid crystalline compound exhibited photochromism in the crystalline solid phase. Although photochromism was not observed in the nematic gel state of the mixture, the lifetime of photochromism in the solid phase became longer, compared with that of a single liquid crystalline compound. Some Raman bands of the mixture showed a marked change in both intensity and frequency through the phase transitions. These bands have been assigned to the vibrational modes related to the core part of molecule. 相似文献
50.
New homologous series of N-[4-(4-n-alkoxybenzoyloxy)-2-hydroxybenzylidene]-3-aminopyridines were synthesized, they exhibited a nematic phase. The temperature dependence of their Raman spectra has been observed in the spectral range 900-1800 cm-1. Some Raman bands show a marked change in their intensity and frequency through the phase transition from crystalline solid to nematic. These bands are ascribed to the vibrational modes related to the core part of the molecule. Such behaviour can be explained by the change of molecular conformation related to the core. Some members of these series exhibited photochromism in the solid state. 相似文献