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41.
Matsuda A Fushitani M Takahashi EJ Hishikawa A 《Physical chemistry chemical physics : PCCP》2011,13(19):8697-8704
The visualization of ultrafast isomerization of deuterated acetylene dication (C(2)D(2)(2+)) is demonstrated by time-resolved Coulomb explosion imaging with sub-10 fs intense laser pulses (9 fs, 0.13 PW cm(-2), 800 nm). The Coulomb explosion imaging monitoring the three-body explosion process, C(2)D(2)(3+)→ D(+) + C(+) + CD(+), as a function of the delay between the pump and probe pulses revealed that the migration of a deuterium atom proceeds in a recurrent manner; One of the deuterium atoms first shifts from one carbon site to the other in a short timescale (~90 fs), and then migrates back to the original carbon site by 280 fs, in competition with the molecular dissociation. Correlated motion of the two deuterium atoms associated with the hydrogen migration and structural deformation to non-planar geometry are identified by the time-resolved four-body Coulomb explosion imaging, C(2)D(2)(4+)→ D(+) + C(+) + C(+) + D(+). 相似文献
42.
Reaction efficiencies of two organic alkalis, tetramethylammonium hydroxide (TMAH) and trimethylsulfonium hydroxide (TMSH), with lipids during thermally assisted hydrolysis and methylation (THM) were examined focusing on (1) the types of lipids and (2) degree of unsaturation of fatty acid moieties. Different types of lipids such as triglycerides, phospholipids, free fatty acids and cholesteryl esters containing saturated, monounsaturated or polyunsaturated fatty acid (PUFA) residues were subjected to THM-gas chromatography (GC) in the presence of TMAH or TMSH. The obtained results revealed that the THM reaction using TMAH allowed almost quantitative methylation of saturated and monounsaturated fatty acid components independently of the classes of lipids. However, strong alkalinity of TMAH brought about isomerization and/or degradation of PUFA components. In contrast, the use of TMSH was effective to highly sensitive detection of PUFA as well as saturated and monounsaturated fatty acid components contained in triglycerides, phospholipids (phosphatidylcholines) and free fatty acids. On the other hand, TMSH was proved to react hardly with any kind of fatty acid residues in cholesteryl esters due to their steric hindrance. 相似文献
43.
Frank Schilder Jan Rübel Jens Starke Hinke M. Osinga Bernd Krauskopf Mizuho Inagaki 《Nonlinear dynamics》2008,51(4):529-539
We present a numerical method for the investigation of quasiperiodic oscillations in applications modeled by systems of ordinary
differential equations. We focus on systems with parts that have a significant rotational speed. An important element of our
approach is that it allows us to verify whether one can neglect gravitational forces after a change of coordinates into a
corotating frame. Specifically, we show that this leads to a dramatic reduction of computational effort. As a practical example,
we study a turbocharger model for which we give a thorough comparison of results for a model with and without the inclusion
of gravitational forces. 相似文献
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The quantum yields of singlet oxygen formation (ØΔ) by the quenching of triplet states of organic sensitizers are measured at various concentrations of the sensitizers by using the time-resolved thermal lens method. Above a certain concentration, ØΔ is independent of the sensitizer concentration. Below the threshold, ØΔ gradually decreases as the concentration of the sensitizer decreases. The extrapolation of ØΔ to zero concentration indicates that singlet oxygen formation is not necessarily dominant in the quenching process even for the 3ππ* state in benzene. 相似文献
49.
Heteroleptic [Bis(oxazoline)](dipyrrinato)zinc(II) Complexes: Bright and Circularly Polarized Luminescence from an Originally Achiral Dipyrrinato Ligand
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Dr. Julius F. Kögel Dr. Shinpei Kusaka Dr. Ryota Sakamoto Toshiki Iwashima Mizuho Tsuchiya Ryojun Toyoda Ryota Matsuoka Dr. Takamasa Tsukamoto Dr. Junpei Yuasa Prof. Dr. Yasutaka Kitagawa Prof. Dr. Tsuyoshi Kawai Prof. Dr. Hiroshi Nishihara 《Angewandte Chemie (International ed. in English)》2016,55(4):1377-1381
Heteroleptic zinc(II) complexes synthesized using achiral dipyrrinato and chiral bis(oxazoline) ligands show bright fluorescence with quantum efficiencies of up to 0.70. The fluorescence originates from the 1π–π* photoexcited state localized exclusively on the dipyrrinato ligand. Furthermore, the luminescence is circularly polarized despite the achirality of the dipyrrinato ligand. Single‐crystal X‐ray structure analysis discloses that the chiral bis(oxazoline) ligand undergoes intramolecular π–π stacking with the dipyrrinato ligand, inducing axial chirality in the dipyrrinato moiety. 相似文献
50.
The consecutive determination of rutin and quercetin without any pretreatment for separation was examined in methanol solutions by a conventional and a two-wavelength spectrophotometry. Based the tendency of quercetin to form more stable metal complexes compared to rutin, quercetin can be determined through the tin(II) complex formation without interference from rutin. The method was applied to the determination of quercetin in the concentration range of 3.0 × 10?6 to 2.0 × 10?5M.Quercetin is apt to be oxidized by oxygen rather than rutin, especially in the presence of copper(II), whereas rutin is not decomposed under such a condition. After removal of quercetin through copper(II)-catalyzed oxidation, rutin ranging in concentration from 2.0 × 10?6 to 2.0 × 10?M was determined by the absorbance measurement of rutin-copper(II) complex in slightly alkaline methanol media.Both rutin and quercetin were determined directly by two-wavelength spectrophotometry, without adding any complex forming metals; the lower limit of detection was about 1.0 × 10?5M. The method was extended to the determination of a smaller amounts of rutin and quercetin using the absorption peaks of their zirconium(IV) complexes, and the determination of both components in the range of 5.0 × 10?6 to 3.0 × 10?5M was made with a relative error of within ±4%. 相似文献