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121.
Peng Xia Tatsuki Tahara Takashi Kakue Yasuhiro Awatsuji Kenzo Nishio Shogo Ura Toshihiro Kubota Osamu Matoba 《Optical Review》2013,20(2):193-197
To improve the quality of reconstructed images, we apply bicubic interpolation and B-spline interpolation to parallel phase-shifting digital holography for the first time. The effectiveness of bilinear interpolation, bicubic interpolation, and B-spline interpolation in parallel phase-shifting digital holography is shown by a numerical simulation. In the simulation result, the application of bicubic interpolation and B-spline interpolation succeeded in decreasing the rootmean- square error of the reconstructed image by 12.6 and 11.9%, respectively. 相似文献
122.
Shogo Ihara Takashi Soma Daigo Yano Shunichi Aikawa Yasuhiko Yoshida 《Journal of heterocyclic chemistry》2011,48(3):577-581
The cycloaddition reaction of cyclic imidates, 2‐benzyl‐5,6‐dihydro‐4H‐1,3‐oxazines 1a , 1b , 1c , 1d , 1e , 1f , with dimethyl acetylenedicarboxylate 2 , trimethyl ethylenetricarboxylate 4 , or dimethyl 2‐(methoxymethylene)malonate 6 afforded new fused heterocyclic compounds, such as methyl (6‐oxo‐3,4‐dihydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐ylidene)acetates 3a , 3b , 3c , 3d , 3e , 3f (71–79%), dimethyl 2‐(6‐oxo‐3,4,6,7‐tetrahydro‐2H‐pyrrolo[2,1‐b]‐1,3‐oxazin‐7‐yl)malonates 5b , 5c , 5d , 5e , 5f (43–71%), or methyl 6‐oxo‐3,4‐dihydro‐2H,6H‐pyrido[2,1‐b]‐1,3‐oxazine‐7‐carboxylates 7a , 7b , 7c , 7d , 7e , 7f (32–59%), respectively. In these reactions, 1a , 1b , 1c , 1d , 1e , 1f (cyclic imidates, iminoethers) functioned as their N,C‐tautomers (enaminoethers) 2 to α,β‐unsaturated esters 2 , 4, and 6 to give annulation products 3 , 5 , and 7 following to the elimination of methanol, respectively. J. Heterocyclic Chem., (2011). 相似文献
123.
Only a handful of aziridine-containing natural products have been identified out of the more than 100,000 natural products characterized to date. Among this class of compounds, only the azinomycins (azinomycin A and B) and ficellomycin contain an unusual 1-azabicyclo[3.1.0]hexane ring system, which has been reported to be the reason for theDNAcrosslinking abilities and cytotoxicity of these metabolites. Both families of natural products are produced by Streptomyces species, Streptomyces sahachiroi and Streptomyces ficellus, respectively. Up until recently, much of the work on these molecules has focused on the synthesis of these natural products or their corresponding analogs for in vitro investigations evaluating their DNA selectivity. While one of the most intriguing aspects of these natural products is their biosynthesis, progress made in this area was largely impeded by difficulties with obtaining a reliable culture method and securing a consistent source of these natural products. In this review, we will cover the discovery and biological activity of the azinomycins, their mode of action, related synthetic analogs and biosynthesis, and finish with a discussion on the less studied metabolite, ficellomycin. 相似文献
124.
Ivaylo Dimitrov Shogo Takamuku Katja Jankova Patric Jannasch Sren Hvilsted 《Macromolecular rapid communications》2012,33(16):1368-1374
A multi‐step synthetic strategy to polysulfone (PSU) grafted with phosphonated poly(pentafluorostyrene) (PFS) is developed. It involves controlled radical polymerization resulting in alkyne‐end functional PFS. The next step is the modification of PSU with a number of azide side groups. The grafting of PFS onto PSU backbone is performed via the “click”‐chemistry approach. In a final step, the PFS‐grafts are subjected to the post phosphonation. The copolymers are evaluated as membranes for potential fuel cell applications through thermal analyses, water uptake, and conductivity measurements. The proposed synthetic route opens the possibility to tune copolymers’ hydrophilic–hydrophobic balance to obtain membranes with an optimal balance between proton conductivity and mechanical properties. 相似文献
125.
Bo Zhao Karan Bhuripanyo Keya Zhang Hiroaki Kiyokawa Hermann Schindelin Jun Yin 《Chemistry & biology》2012,19(10):1265-1277
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126.
Linlin Wu Chiemi Kojima Ka-Ho Lee Shogo Morisako Zhenyang Lin Makoto Yamashita 《Chemical science》2021,12(28):9806
Transition metal-free direct and base-catalyzed 1,2-diborations of arylacetylenes using pinB-BMes2 provided a syn/anti-isomeric mixture of diborylalkenes. The kinetic analysis showed that the reaction rate and isomer ratio were affected by reaction conditions and substituents on the aryl ring. DFT calculations indicated that direct addition proceeded via the interaction of acetylene-π with the BMes2 fragment. In contrast, for the base-catalyzed diboration, the previously isolated sp2–sp3 diborane and borataallene were confirmed as stable intermediates by calculations. The whole reaction pathways can be divided into the Bpin-migration and deprotonation steps, where the borataallene should be considered as a common intermediate. It should be noted that the deprotonation step is reversible and affords the kinetically less favoured isomer under the thermodynamic conditions. As a result, the composition of isomeric products, in the base-catalyzed diboration, is attributed to the small difference of activation barriers between direct and base-catalyzed systems.Combination of kinetic and DFT studies revealed a subtle balance for substituent effect toward the regioselectivity of the product in metal-free and base-catalyzed diboration of arylacetylenes. 相似文献
127.
A cavity-resonator-integrated guided-mode resonance filter (CRIGF) has been proposed and investigated in order to realize high-efficiency narrowband reflection with a small aperture. The CRIGF consists of a grating coupler integrated in a cavity resonator constructed by a pair of distributed Bragg reflectors on a thin-film waveguide. This time, orthogonally crossed integration of two CRIGFs was demonstrated in order to obtain polarization-independent reflection spectrum. An SiO2-based device with 10?μm aperture was designed and fabricated for around 850?nm wavelength operation, and narrowband polarization-independent reflection was confirmed experimentally. 相似文献
128.
Tatsuki Tahara Akifumi Maeda Yasuhiro Awatsuji Kenzo Nishio Shogo Ura Toshihiro Kubota Osamu Matoba 《Optical Review》2012,19(6):366-370
We propose a single-shot phase unwrapping technique using a single wavelength and parallel phase-shifting interferometry. In the proposed technique, an object is illuminated by two laser beams, which are emitted from the same laser, and have different illumination angles and polarizations. Two types of object waves generated by the two beams are separately and simultaneously recorded by a polarization-imaging camera. In the path of the reference wave, an array of phase retarders is placed to implement the parallel phase-shifting technique. A highly accurate three-dimensional shape is reconstructed from a single hologram. We numerically simulated the proposed technique and conducted a preliminary experiment to verify its effectiveness. It was confirmed that millimeter-order height, which was several thousand times the wavelength of the laser, can be reconstructed by the proposed technique without wrapping. 相似文献
129.
Takashi Yamazaki Tomoko Kawasaki-Takasuka Atsushi Furuta Shogo Sakamoto 《Tetrahedron》2009,65(31):5945-1960
Smooth isomerization of 4,4,4-trifluorinated propargylic alcohols 1 opened a new and convenient route to readily get access to the corresponding α,β-unsaturated ketones 4 just by heating a THF solution in the presence of Et3N. 相似文献
130.
Tatsuki Tahara Yasuhiro Awatsuji Atsushi Kaneko Takamasa Koyama Kenzo Nishio Shogo Ura Toshihiro Kubota Osamu Matoba 《Optical Review》2010,17(3):108-113
We propose an optical implementation of a parallel two-step phase-shifting digital holography that utilizes a polarization
technique. The implementation uses a phase-shifting array device consisting of a retarder array attached to an image sensor,
and does not require the optical system to image the phase-shifting array device onto the image sensor required for the previously
reported optical implementation of the parallel two-step phase-shifting digital holography. Then, the proposed implementation
is essentially simple to align and compose. A preliminary experiment showed that the parallel two-step phase-shifting digital
holography based on the proposed implementation can remove the conjugate image clinging to the image reconstructed by Fresnel
transform alone with DC term suppression. Also, when the reconstruction distance was changed, the qualities of the reconstructed
images were quantitatively evaluated by using normalized root-mean-square error. It was clarified that the proposed implementation
was superior to other parallel phase-shifting digital holographies and Fresnel transform alone. Thus, the validity of the
proposed implementation was confirmed. 相似文献