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341.
Dr. Kei Yoshida Kosuke Okada Dr. Hirofumi Ueda Prof. Dr. Hidetoshi Tokuyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(51):23289-23293
We have established a highly convergent 10-step route for the total synthesis of (−)-deoxoapodine, which is a hexacyclic aspidosperma alkaloid. The quaternary C5 center of the characteristic tetrahydrofuran ring was constructed by a chiral-phosphoric-acid-catalyzed enantioselective bromocycloetherification in a 5-endo fashion and subsequent allylation by using the Keck protocol. Construction of the aspidosperma skeleton features the formation of a nine-membered lactam by a catalytic C−H palladation/alkylation cascade at the indole 2-position and an iron-catalyzed oxidative transannular reaction at a late-stage of the synthesis. 相似文献
342.
We report the quantitative relationship between the phase-matching condition and the surrounding temperature in a critical phase-matching second-harmonic generation of a Q-switched Nd:YVO4 laser with a high repetition rate. The thermal effect can be effectively compensated for by appropriately changing the phase-matching angle with respect to the surrounding temperature of a nonlinear optical crystal. A stable wavelength conversion from the 1064 nm fundamental to the 532 nm second harmonic in a type-I critical phase-matching lithium triborate crystal is experimentally achieved and the corresponding conversion efficiency up to 70% is obtained. 相似文献
343.
A novel formation method of a long-period fiber grating (LPFG) based on a magnetic-force-induced microbend is proposed and experimentally demonstrated. The LPFG employs a permanent magnet that exerts transversal force to the fiber by attracting a steel coil spring. The transversal force causes periodic microbending to the fiber, and therefore the transmission wave attenuates at the core-to-cladding mode resonance. This device has advantages of ease of fabrication, reconfigurability, and available for any type of fiber. 相似文献
344.
Kosuke Ono 《Journal of Mathematical Analysis and Applications》2003,286(2):540-562
Consider the initial boundary value problem for the linear dissipative wave equation (□+∂t)u=0 in an exterior domain . Using the so-called cut-off method together with local energy decay and L2 decays in the whole space, we study decay estimates of the solutions. In particular, when N?3, we derive Lp decays with p?1 of the solutions. Next, as an application of the decay estimates for the linear equation, we consider the global solvability problem for the semilinear dissipative wave equations (□+∂t)u=f(u) with f(u)=|u|α+1,|u|αu in an exterior domain. 相似文献
345.
Kosuke Makiguchi Tatsuya Saito Toshifumi Satoh Toyoji Kakuchi 《Journal of polymer science. Part A, Polymer chemistry》2014,52(14):2032-2039
The ring‐opening polymerization (ROP) of β‐butyrolactone (β‐BL) has been studied using the organocatalysts of diphenyl phosphate (DPP) and bis(4‐nitrophenyl) phosphate (BNPP). The controlled ROP of β‐BL was achieved using BNPP, whereas that of using DPP was insufficient because of its low acidity. For the BNPP‐catalyzed ROP of β‐BL, the dual activation property for β‐BL and the chain‐end models of poly(β‐butyrolactone) (PBL) were confirmed by NMR measurements. The optimized polymerization condition for the ROP of β‐BL proceeded through an O‐acyl cleavage to produce the well‐defined PBLs with molecular weights up to 10,650 g mol?1 and relatively narrow polydispersities of 1.19–1.39. Functional initiators were utilized for producing the end‐functionalized PBLs with the ethynyl, maleimide, pentafluorophenyl, methacryloyl, and styryl groups. Additionally, the diblock copolymers consisting of the PBL segment with the polyester or polycarbonate segments were prepared by the BNPP‐catalyzed ROPs of ε‐caprolactone or trimethylene carbonate without quenching. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2032–2039 相似文献
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347.
Nogo Kosuke Qi Wei Mori Keita Ogawa Satoshi Inohara Daichi Hosono Satsuki Kawashima Natsumi Nishiyama Akira Wada Kenji Ishimaru Ichiro 《Optical Review》2016,23(2):360-363
Optical Review - Application of spectroscopic techniques to suspensions is difficult because optical scattering caused by solid particles reduces the accuracy. At the extreme, dense suspensions... 相似文献
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Nishio K Masaike Y Ikeda M Narimatsu H Gokon N Tsubouchi S Hatakeyama M Sakamoto S Hanyu N Sandhu A Kawaguchi H Abe M Handa H 《Colloids and surfaces. B, Biointerfaces》2008,64(2):162-169
We developed novel magnetic nano-carriers around 180 nm in diameter for affinity purification. Prepared magnetic nano-carriers possessed uniform core/shell/shell nano-structure composed of 40 nm magnetite particles/poly(styrene-co-glycidyl methacrylate (GMA))/polyGMA, which was constructed by admicellar polymerization. By utilizing relatively large 40 nm magnetite particles with large magnetization, the magnetic nano-carriers could show good response to permanent magnet. Thanks to uniform polymer shell with high physical/chemical stability, the magnetic nano-carriers could disperse in a wide range of organic solvent without disruption of core/shell structure and could immobilize various kinds of drugs. We examined affinity purification using our prepared magnetic nano-carriers with anti-cancer agent methotrexate (MTX) as ligand. Our magnetic nano-carriers showed higher performance compared to commercially available magnetic beads in terms of purification efficiency of target including extent of non-specific binding protein. 相似文献