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131.
Tavrov A Korablev O Ksanfomaliti L Rodin A Frolov P Nishikwa J Tamura M Kurokawa T Takeda M 《Optics letters》2011,36(11):1972-1974
To suppress starlight for direct exoplanet observation, we propose a common-path achromatic rotational-shearing coronagraph (CP-ARC), which is an interferocoronagraph with an angular-adjustable field rotator. The CP-ARC aims to maintain unwanted detection of stellar light, which can be suppressed incompletely by interference because of the finite diameter of the star. Compared to the previous interferocoronagraph, which had a nonadjustable 180° field rotation, the proposed CP-ARC can improve the coronagraphic contrast by several orders if the CP-ARC is combined with medium or large telescopes where the companion-star separation is optically resolved by more than a few Airy radii. The CP-ARC is made robust against mechanical disturbances due to the common-path interferometer principle. 相似文献
132.
Corrosion and passivation behavior of Mg-Zn-Y-Al alloys prepared by cooling rate-controlled solidification 总被引:1,自引:0,他引:1
Michiaki Yamasaki Shogo IzumiYoshihito Kawamura Hiroki Habazaki 《Applied Surface Science》2011,257(19):8258-8267
Highly corrosion-resistant nanocrystalline Mg-Zn-Y-Al multi-phase alloys have been prepared by consolidation of rapidly solidified (RS) ribbons. The relation between corrosion behavior and microstructure evolution of Mg-Zn-Y-Al alloys with a long period stacking ordered phase has been investigated. In order to clarify the influence of rapid solidification on the occurrence of localized corrosion such as filiform corrosion, several Mg96.75Zn0.75Y2Al0.5 (at.%) alloys with different cooling rates are fabricated by the gravity casting, copper mould injection casting and melt-spinning techniques and their corrosion behavior and microstructures are examined by the salt water immersion test, electrochemical measurements, GDOES, XRD, SEM and TEM. To clarify the effect of aluminium addition on the improvement in corrosion resistance of the alloys, several Mg97.25−xZn0.75Y2Alx alloys with different aluminium contents are fabricated by consolidating RS ribbons and the formation of corroded films on the Mg-Zn-Y-Al alloys have been investigated. Rapid solidification brings about the grain refinement and an increase in the solid solubility of zinc, yttrium and aluminium into the magnesium matrix, enhancing microstructural and electrochemical homogeneity, which in turn enhanced corrosion resistance. The addition of aluminium to magnesium can modify the structure and chemical composition of surface films and improves the resistance to local breakdown of the films. 相似文献
133.
134.
Takumi Abe Hiroyuki Takeda Yoshihisa Miwa Koji Yamada Reiko Yanada Minoru Ishikura 《Helvetica chimica acta》2010,93(2):233-241
It was shown that dichloramine‐T ( 1 ) reacted with cyclohexene in acetonitrile to give N1‐(2‐chlorocyclohexyl) amidine 2a and N‐(2‐chlorocyclohexyl)acetamide ( 3 ) via the competitive addition of acetonitrile and N‐chloro‐N‐tosylamino anion to cyclohexenechloronium ion. This reaction can be catalyzed by Cu(OAc)2, primarily affording 2a . Furthermore, the resulting 2a can be cyclized to benzimidazol 14a in good yield by treating with KOH in dioxane. 相似文献
135.
K. Yanagisawa H. Takeda K. Miyamoto S. Fuma N. Ishii 《Journal of Radioanalytical and Nuclear Chemistry》2002,251(2):277-280
Tracer experiments on the transfer of carbon from culture solution to Daphnia magna through phytoplankton have been carried out using 13C and infrared absorption method. The purpose of this experiment is to investigate the experimental systems for the use of 13C in aquatic system. Daphnia magna was cultured in a 100 ml of solution containing phytoplankton and 20 mg of NaH13CO3 for 24 hours in the light and dark conditions (2000 lux, 14 hour light and 10 hours dark at 25 C). The concentration of 13C in Daphnia magna under light condition was about 2.0% (atom% excess), while in the dark condition 13C tracer was not detected. The concentration of 13C in phytoplankton under light condition was around 20%. It was suggested that 13C added as carbonate in the culture solution was photosynthetically assimilated by phytoplankton and then transferred to Daphnia magna. Using this system, the effect of UV-B exposure on the 13C uptake of Daphnia magna has been examined. The UV-B intensity was 95 mW/cm2 and exposure time was 15, 30, and 60 minutes. The concentration of 13C in Daphnia magna decreased with increasing exposure time. The Daphnia magna exposed to UV-B for 15 minutes intakes phytoplankton as much as control, while 30 minutes and 60 minutes exposures were lower than control. The lower concentrations of 13C observed in Daphnia magna were due to less intake of phytoplankton caused by the UV-B exposure. 相似文献
136.
Hidekazu Kumano Satoshi Kimura Michiaki Endo Ikuo Suemune Hirotaka Sasakura Satoru Adachi Shunichi Muto Hai Zhi Song Shinichi Hirose Tatsuya Usuki 《Physica E: Low-dimensional Systems and Nanostructures》2006,32(1-2):144
Triggered single-photon generation from InAlAs quantum dot (QD) was demonstrated for the first time. Emitted photon energy coincides with high detection efficiency range of Si single-photon detectors, which is highly suitable for free-space communication. Single-QD spectroscopy and crossed photon correlation measurements unambiguously revealed that several emitting lines observed in a single mesa structure originated from the identical QD, and two temporary competing decay processes associated with neutral states and charged states were identified. Presence of the competing process is also inferred from an analysis of steady-state photoluminescence intensities. Formation process of charged exciton in QD is also discussed. 相似文献
137.
The alignment correlation term in the β-decay angular distribution from purely nuclear spin aligned 20Na has been measured for the first time. The final objective is to test the G parity symmetry, one of the fundamental symmetry in the weak nucleon current. For artificial creation of the alignment, the
knowledge of the hyperfine interaction of 20Na implanted in a single-crystal ZnO was utilized.
*Research Abroad, Japan Society for the Promotion of Science 相似文献
138.
Akiko Takeda Katsuki Fujisawa Yusuke Fukaya Masakazu Kojima 《Journal of Global Optimization》2002,24(2):237-260
As computing resources continue to improve, global solutions for larger size quadrically constrained optimization problems become more achievable. In this paper, we focus on larger size problems and get accurate bounds for optimal values of such problems with the successive use of SDP relaxations on a parallel computing system called Ninf (Network-based Information Library for high performance computing). 相似文献
139.
140.
Atsushi Wada Hiroyuki Ohminato Takashi Yonemura Yoko Miyamoto Mitsuo Takeda 《Optical Review》2005,12(6):451-455
Seidel comatic aberration is an important cause of deformation for a Laguerre--Gaussian (LG) beam. In addition, mono-axial
comatic aberration, whose phase modulation depends only on one transverse coordinate, is also an important cause of beam deformation.
Deformation of an LG beam by such aberrations is analyzed through numerical simulation based on the angular spectrum method.
It is also shown that for holographically generated LG beams quadratic spatial variation of grating pitch can produce seidel
and mono-axial comatic aberrations. An example of an experimentally generated LG beam with mono-axial comatic aberration is
reported. 相似文献