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排序方式: 共有626条查询结果,搜索用时 15 毫秒
91.
We present a simple framework for constructing de Bruijn sequences, and more generally, universal cycles, via successor rules. The framework is based on the often used method of joining disjoint cycles. It generalizes four previously known de Bruijn sequence constructions and is applied to derive three new and simple de Bruijn sequence constructions. Four of the constructions apply the pure cycling register and three apply the complemented cycling register. The correctness of each new construction is easily proved using the new framework. Each of the three new de Bruijn sequence constructions can be generated in -time per bit using -space. 相似文献
92.
The addition of nematic compounds with high clearing points (Nh) to multiplexable nematic liquid crystals decreases the temperature dependence of the threshold voltage of twisted nematic displays. This effect depends on the dielectric anisotropy of the nematic liquid crystals containing Nh, as well as on the increase in T c. In the case of 4-n-butylphenyl 4'-(4”-butyibenzoyloxy) benzoate, the low threshold voltage was exceptionally compatible with a small temperature dependence of threshold voltage, and this result was attributed to the large temperature dependence of the dielectric anisotropy in comparison with that of nematic liquid crystals containing other Nh's. 相似文献
93.
Tadakazu Sawada 《代数通讯》2013,41(5):1633-1639
A vector bundle on a hypersurface is arithmetically Cohen–Macaulay if its intermediate cohomologies vanish. On projective spaces, such bundles coincide with those which split into a direct sum of line bundles, but this fails on hypersurfaces of higher degree in general. In this article, we give an inequality which gives a sufficient condition for splitting of arithmetically Cohen–Macaulay bundles on general hypersurfaces. 相似文献
94.
95.
Ami Saito Dr. Tomohisa Sawada Prof. Dr. Makoto Fujita 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20547-20550
Porous metal complexes enable single-crystal X-ray crystallographic observation of included guests or reaction intermediates through simple soaking with the guests/substrates. Previous studies on this technique have often encountered difficulties in the observation of chiral structures because the host frameworks had no chirality. We synthesized a new metal–peptide porous complex through a folding-and-assembly strategy and utilized the chiral pore for trapping chiral guests. Chiral alcohols and ketones were successfully included within the pore. Crystallographic analyses clearly revealed not only their chemical structures but also chiral transformation events within the pore such as fixed conformations or an unstable hemiacetal formation. 相似文献
96.
Honda S Akiba T Kato YS Sawada Y Sekijima M Ishimura M Ooishi A Watanabe H Odahara T Harata K 《Journal of the American Chemical Society》2008,130(46):15327-15331
What is the smallest protein? This is actually not such a simple question to answer, because there is no established consensus among scientists as to the definition of a protein. We describe here a designed molecule consisting of only 10 amino acids. Despite its small size, its essential characteristics, revealed by its crystal structure, solution structure, thermal stability, free energy surface, and folding pathway network, are consistent with the properties of natural proteins. The existence of this kind of molecule deepens our understanding of proteins and impels us to define an "ideal protein" without inquiring whether the molecule actually occurs in nature. 相似文献
97.
Shitao Wang Dr. Tomohisa Sawada Dr. Kazuaki Ohara Prof. Dr. Kentaro Yamaguchi Prof. Dr. Makoto Fujita 《Angewandte Chemie (International ed. in English)》2016,55(6):2063-2066
Guest‐induced M18L6–M24L8 capsule–capsule conversion is reported. Both capsules are composed of PdII ethylenediamine units (M) and 1,3,5‐tris(3,5‐pyrimidyl)pyrimidine (L), and form trigonal bipyramidal (M18L6) and octahedral (M24L8) closed‐shell structures with huge hydrophobic inner spaces. The M18L6 trigonal bipyramid is converted to the M24L8 octahedron through encapsulation of large aromatic guests, with the latter capsule possessing a cavity volume three times larger than the former. Despite the dynamic properties of the capsule host, the encapsulated guests are difficult to extract and are thus isolated from the external environment. 相似文献
98.
New Types of Planar Chiral [2.2]Paracyclophanes and Construction of One‐Handed Double Helices
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Prof. Yasuhiro Morisaki Risa Sawada Dr. Masayuki Gon Prof. Yoshiki Chujo 《化学:亚洲杂志》2016,11(18):2524-2527
New types of planar chiral (Rp)‐ and (Sp)‐4,7,12,15‐tetrasubstituted [2.2]paracyclophanes were synthesized from racemic 4,12‐dihydroxy[2.2]paracyclophane as the starting compound. Regioselective dibromination and transformation afforded a series of planar chiral (Rp)‐ and (Sp)‐4,7,12,15‐tetrasubstituted [2.2]paracyclophanes, which can be used as chiral building blocks. In this study, left‐ and right‐handed double helical structures were constructed via chemoselective Sonogashira–Hagihara coupling. The double helical compounds were excellent circularly polarized luminescence (CPL) emitters with large molar extinction coefficients, good photoluminescence quantum efficiencies, and large CPL dissymmetry factors. 相似文献
99.
100.
Yoshioka H Suzuki M Mugisawa M Naitoh N Sawada H 《Journal of colloid and interface science》2007,308(1):4-10
Fluoroalkanoyl peroxide reacted with 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (TTRV-Si) to afford fluoroalkyl end-capped oligomers containing some unreacted vinyl segments under very mild conditions. Fluoroalkyl end-capped cyclosiloxane oligomers containing some vinyl segments thus obtained reacted with N,N-dimethylacrylamide and fluoroalkanoyl peroxide to afford new fluorinated dendrimer-type block copolymers in good isolated yield. Similar reactions were also occurred by the use of 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane instead of TTRV-Si, and the corresponding fluorinated dendrimer-type block copolymer was obtained in good isolated yield. These fluorinated dendrimer-type block copolymers had an excellent solubility not only in water but also in traditional organic solvents including aliphatic fluorinated solvents. Interestingly, these fluorinated block copolymers were found to form the self-assembled dendrimer-type polymeric aggregates in aqueous solutions. More interestingly, these fluorinated block copolymers had an extremely higher dispersion ability of not only single-walled carbon nanotube and fullerenes but also magnetic nanoparticles into water, compared to that of the corresponding two fluoroalkyl end-capped oligomers. 相似文献