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排序方式: 共有610条查询结果,搜索用时 209 毫秒
571.
Yoshinori Yamanoi Tsukasa Usuki Kenichiro Omoto Masaki Shimada Hikaru Koike Munetaka Iwamura Koichi Nozaki Daisuke Saito Masako Kato Hiroshi Nishihara 《Tetrahedron letters》2019,60(16):1108-1112
Planar chiral dioxacyclophanes were designed and synthesized as a key scaffold for materials with circularly polarized luminescence (CPL). Representative planar chiral 1,12-dioxa[12](1,4)naphthaleneophane-derived organosilane compounds (?)-(R)-1, (+)-(R)-2, and (?)-(R)-3 were prepared by (+)-sparteine-mediated aryl metalation and an electrophilic reaction with chlorosilanes. The absolute configurations of the planar chirality were determined in the R form by single-crystal X-ray analysis. Optically active compound (+)-(R)-2 exhibited blue fluorescence and a CPL signal with a dissymmetry factor (glum value) of 0.001 in solution. The electronic structure was corroborated by DFT and TD-DFT calculations rationalizing the observed spectroscopic properties. 相似文献
572.
Akira Sasaki Atsushi Sunahara Hiroyuki Furukawa Katsunobu Nishihara Takeshi Nishikawa Fumihiro Koike Hajime Tanuma 《High Energy Density Physics》2009,5(3):147-151
We present the development of population kinetics models for tin plasmas that can be employed to design an EUV source for microlithography. The atomic kinetic code is constrained for the requirement that the model must be able to calculate spectral emissivity and opacity that can be used in radiation hydrodynamic simulations. Methods to develop compact and reliable atomic model with an appropriate set of atomic states are discussed. Specifically, after investigation of model dependencies and comparison experiment, we improve the effect of configuration interaction and the treatment of satellite lines. Using the present atomic model we discuss the temperature and density dependencies of the emissivity, as well as conditions necessary to obtain high efficiency EUV power at λ = 13.5 nm. 相似文献
573.
We present a leading order (LO) estimate for the longitidinal-transverse spin asymmetry (A
) in the nucleon-nucleon polarized Drell-Yan process at RHIC and
energies in comparison with A
and A
. A
receives contribution from g1, the transversity distribution h1, and the twist-3 distributions g
and h
. For the twist-3 contribution we use the bag model prediction evolved to a high energy scale by the large-Nc evolution equation. We found that A
(normalized by the asymmetry in the parton level) is much smaller than the corresponding A
. Twist-3 contribution given by the bag model turned out to be negligible. 相似文献
574.
Taniguchi A Sohma Y Kimura M Okada T Ikeda K Hayashi Y Kimura T Hirota S Matsuzaki K Kiso Y 《Journal of the American Chemical Society》2006,128(3):696-697
A clear understanding of the dynamic events of amyloid beta peptide (Abeta) 1-42, such as the folding, self-assembly, and aggregation processes, would be of great significance in Alzheimer's disease (AD) research. However, elucidation of these Abeta1-42 dynamic events is a difficult issue due to uncontrolled polymerization, which also poses a significant obstacle for establishing an experimental system that clarifies the pathological function of Abeta1-42. On the basis of the O-acyl isopeptide method, we herein developed a novel photo-triggered "click peptide" of Abeta1-42, for example, 26-N-Nvoc-26-AIAbeta42, in which the photocleavable 6-nitroveratryloxycarbonyl (Nvoc) group was introduced at the alpha-amino group of Ser26 in 26-O-acyl isoAbeta1-42 (26-AIAbeta42). From the results, (1) the click peptide did not exhibit the self-assembling nature under physiological conditions due to one single modified ester; (2) photoirradiation of the click peptide and subsequent O-N intramolecular acyl migration afforded the intact Abeta1-42 with a quick and one-way conversion reaction (so-called "click"), while the click peptide was stable under nonphotolytic or storage conditions. In addition, it is advantageous that no additional fibril inhibitory auxiliaries were released during conversion to Abeta1-42. This method provides a novel system useful for investigating the dynamic biological functions of Abeta1-42 in AD by inducible activation of Abeta1-42 self-assembly. 相似文献
575.
576.
Tooru Kitagawa 《Journal of Macromolecular Science: Physics》2017,56(3):178-193
The research described in this article was primarily concerned with the preferential orientations of crystal planes along the radial direction normal to the fiber axis, using fibers of poly-p-phenylenebenzobisoxasole as an example. The focus is placed on the formation of the preferential orientation during the dry-jet wet spinning fiber production process for rigid-rod polymers in which, after coagulation, the fibers are washed and dried at low temperatures. It is suggested that the formation of the radial or random preferential orientation was determined in the coagulation and washing processes, based on an analysis of micro-focus X-ray diffraction intensities in a synchrotron radiation facility. 相似文献
577.
C. Petrascu S. Bianco A.M. Bragadireanu F.L. Fabbri C. Guaraldo M. Iliescu T.M. Ito V. Lucherini M. Bregant E. Milotti A. Vacchi E. Zavattini M. Augsburger D. Chatellard P. Knowles F. Mulhauser L.A. Schaller L. Schellenberg H. Schneuwly J.-P. Egger D. Varidel W.H. Breunlich M. Cargnelli B. Gartner R. King B. Lauss J. Marton J. Zmeskal T. Ponta S.N. Nakamura T. Koike R.S. Hayano M. Hori T. Ishikawa T. Ishiwatari M. Iwasaki Y. Akaishi G. Beer A.C. Sanderson R. Seki 《Hyperfine Interactions》1999,118(1-4):53-57
The DEAR (DAΦNE Exotic Atom Research) experiment at the new φ-factory DAΦNE of Laboratori Nazionali di Frascati aims for a
1% measurement of the line shift of the K-complex due to strong interaction in kaonic hydrogen. This presentation is meant to prove that the high statistics and good
resolution obtainable with DEAR will be able to disentangle the kaonic hydrogen K-complex lines (a cascade unconstrained fit), obtaining in this way constraints for what concerns the cascade parameters and,
consequently, information regarding the physical processes involved in the kaonic hydrogen atomic cascade.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
578.
Six new acylated triterpenoid saponins, bellisosides A-F (1-6), were isolated from the roots of Bellis perennis (Compositae) together with a known saponin, bellissaponin BS2 (7). These saponins which bear polygalacic acid as sapogenin, are bisdesmosidic glycosides. The structures were elucidated on the basis of chemical and physicochemical evidence. The cytotoxic activities of 1-7 against HL-60 human promyelocytic leukemia cells are also reported. 相似文献
579.
580.
Naoyuki Koike 《Results in Mathematics》2002,42(1-2):81-106
For an equiaffine immersion of general codimension, we recently defined the Lipschitz-Killing curvature, where we fix a transversal bundle and a transversal volume element. The main purpose of this paper is to show that the integration of the absolute value of the Lipschitz-Killing curvature is independent of the choices of a transversal bundle and a transversal volume element. 相似文献