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131.
Topological winding and unwinding in a quasi-one-dimensional metastable Bose-Einstein condensate are shown to be manipulated by changing the strength of interaction or the frequency of rotation. Exact diagonalization analysis reveals that quasidegenerate states emerge spontaneously near the transition point, allowing a smooth crossover between topologically distinct states. On a mean-field level, the transition is accompanied by formation of gray solitons, or density notches, which serve as an experimental signature of this phenomenon. 相似文献
132.
Inada Y Horikoshi M Nakajima S Kuwata-Gonokami M Ueda M Mukaiyama T 《Physical review letters》2008,101(18):180406
We report on measurements of the critical temperature and the temperature dependence of the condensate fraction for a fermion pair condensate of 6Li atoms. Bragg spectroscopy is employed to determine the critical temperature and the condensate fraction after a fast magnetic field ramp to the molecular side of the Feshbach resonance. Our measurements reveal evidence of level off of the critical temperature and limiting behavior of condensate fraction near the unitarity limit. 相似文献
133.
We show that knots of spin textures can be created in the polar phase of a spin-1 Bose-Einstein condensate, and discuss experimental schemes for their generation and probe, together with their lifetime. 相似文献
134.
Yusaku Ogura Masahiro Nakano Hajime Maeda Masahito Segi Taniyuki Furuyama 《Molecules (Basel, Switzerland)》2022,27(9)
Herein, we report the synthesis of sulfur-substituted boron(III) subphthalocyanines (SubPcs) with cationic axial ligands. Subphthalocyanines were synthesized by a condensation reaction using the corresponding phthalonitriles and boron trichloride as a template. An aminoalkyl group was introduced on the central boron atom; this process was followed by N-methylation to introduce a cationic axial ligand. The peripheral sulfur groups shifted the Q band of SubPcs to a longer wavelength. The cationic axial ligands increased the polarity and enhanced the hydrophilicity of SubPcs. The effect of axial ligands on absorption and fluorescence properties is generally small. However, a further red shift was observed by introducing cationic axial ligands into the sulfur-substituted SubPcs. This change is similar to that in sulfur-substituted silicon(IV) phthalocyanines. The unique effect of the cationic axial ligand was extensively investigated by theoretical calculations and electrochemistry. In particular, the precise oxidation potential was determined using ionization potential measurements. Thus, the results of the present study provide a novel strategy for developing functional dyes and pigments based on SubPcs. 相似文献
135.
Rui Umeda Masahito Muraki Yuudai Nakamura Tomoyuki Tanaka Kyohei Kamiguchi Yutaka Nishiyama 《Tetrahedron letters》2017,58(24):2393-2395
The Meinwald rearrangement reaction of oxiranes to the corresponding carbonyl compounds is efficiently catalyzed by the ReBr(CO)5 complex. 相似文献
136.
137.
138.
Masahito Migita Tadashi Okada Noboru Magata Shinji Nishitani Nobuyuki Kurata Yoshiteru Sakata Soichi Misumi 《Chemical physics letters》1981,84(2):263-266
The charge transfer state formed from the S1 state of porphyrin-p-benzoquinone (BQ) model systems in solution has been observed combining octaethylporphyrin and BQ by methylene chains of various lengths. The lifetime of the electron transfer state depends upon the length of the methylene chain and the nature of the solvent. 相似文献
139.
Sakurai O Ogiku T Takahashi M Hayashi M Yamanaka T Horikawa H Iwasaki T 《The Journal of organic chemistry》1996,61(22):7889-7894
Novel syntheses of the 1beta-alkylcarbapenems were achieved on the basis of Eschenmoser sulfide contraction via the new bicyclic 1,3-thiazinone intermediates. 1,3-Thiazinones 7, 16, and 25 were effectively prepared from thioesters 5 and 22 using a C4-S bond formation process. The sulfide contraction reactions were performed by treatment of 7, 16, and 25 with base (NaH or KO-t-Bu) in the presence of triphenylphosphine to generate the corresponding carbapenem enolate 12, 17, and 26, which were trapped by (PhO)(2)POCl followed by the reaction with mercaptans to afford carbapenems 10a, 10b, 19, and 28, respectively. 相似文献
140.
Exposure of 1-alkenyl(phenyl)- and 1-alkynyl(phenyl)-λ3-iodanes to THF at room temperature in the presence of a catalytic amount of trialkylborane results in smooth reduction to give 1-iodo-1-alkenes and 1-iodo-1-alkynes as major products, respectively. The key step in the reductions probably involves a single-electron transfer from α-tetrahydrofuryl radical to the λ3-iodanes, which generates the labile [9-I-2] iodanyl radicals. 相似文献