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21.
Abstract
We experimentally investigated the influence of a head shape of a solid body plunging into water on splash formation. Three different head shapes were tested: a hemisphere, cone, and circular cylinder. A hemisphere as a tail shape is common to all three head shapes. We captured images of splash formation using a high-speed CMOS camera. We found that a film flow generated at an early stage when a body impacts the water surface influences subsequent events until the splash sequence is completed. We explain the origin of the film flow according to the principle of conservation of momentum. The film flow as the primary splash originates from water displaced by the head. The meridian line, which connects the head to the tail of the body, affects separation of the film flow and causes the secondary splash. The air cavity generated when the body plunges into the water is also influenced by the head shape. The tertiary splash is formed by a reaction of the air cavity, which is detached from the body. We found that the secondary dome-type splash obstructs growth of the tertiary splash. Thus, we conclude that the head shape affects all events of the splash. 相似文献22.
Dai Kato Atsumu Oda Mutsuo Tanaka Seiichiro Iijima Tomoyuki Kamata Masami Todokoro Yasuo Yoshimi Osamu Niwa 《Electroanalysis》2014,26(3):618-624
We developed an electrochemical system for detecting lipopolysaccharide (LPS) that uses an ultraflat nanocarbon film electrode modified with poly‐ε‐lysine with a high affinity to LPS. LPS was captured on the modified electrode, and then ferrocene labeled polymyxin B (FcPMB) was captured on the LPS adsorbed electrode via the LPS‐PMB affinity interaction. The adsorbed FcPMB provided an amplified response with Fe2+ ions, and the current response was dependent on the amount of captured LPS (LOD=2.0 ng/mL). This was due to the efficient accumulation of the obtained current for LPS and the very low noise made possible by the ultraflat surface. 相似文献
23.
The chemo- and enantioselective reduction of ethyl 4-chloroacetoacetate and the diastereoselective conjugate addition of enantiopure lithium N-benzyl-N-(α-methylbenzyl)amide to an α,β-unsaturated ester have been used as the key steps in the total asymmetric syntheses of (+)-negamycin (in 13 steps and 24% overall yield), (+)-3-epi-negamycin (in 13 steps and 10% overall yield) and sperabillin C (in 17 steps and 13% overall yield) from commercially available starting materials. 相似文献
24.
2′-Deoxyguanosine (dG) suffers from oxidation by reactive oxygen species (ROS) to form 8-oxo-2′-deoxyguanosine (8-oxo-dG), which is regarded as a marker of oxidative stress in the cells. In our continuous study for the recognition molecule of 8-oxo-dG, 8-oxoGclamp and its derivatives have been identified as the selective fluorescent probe. However, it is an obstacle for further application that dG also forms a complex with 8-oxoGclamp, resulting in fluorescence quenching in less polar solvents. Quenching of the fluorescence of 8-oxoGclamp is thought to involve photo-induced electron transfer in the complex. It was hypothesized that the energy level of the excited state of 8-oxoGclamp and the HOMO energy of dG are the preliminary determinant of the quenching efficiency. Thus, fluorescence properties of the substituted derivatives at the 7-position of the 1,3-diazaphenoxazine part of 8-oxoGclamp were investigated. Among the new derivatives, fluorescence of the 7-phenyl substituted 8-oxoGclamp was not quenched by dG even in the stable complex, exhibiting the highest selectivity for 8-oxo-dG. 相似文献
25.
Masashi NakamuraIsao Takahashi Shunsuke YamadaYasuo Dobashi Osamu Kitagawa 《Tetrahedron letters》2011,52(1):53-55
Intramolecular Diels-Alder reactions of various N-allyl 2-furoyl amides with different substituents on the nitrogen atom were investigated. The reaction of amides having bulky substituents proceeded at a faster rate than the analogs whose substituents were of less bulkiness. From the systematic experimental survey of the substituent effects and the energetic evaluation based on the DFT calculations at the B3LYP/6-31G(d) level, the enhanced reactivity was ascribed to the relief of steric strain upon cyclization rather than the amide rotational isomerism governed by the bulky substituents. 相似文献
26.
Xie Jian Imanishi Nobuyuki Hirano Atsushi Takeda Yashuo Yamamoto Osamu Zhao Xin-Bing Cao Gao-Shao 《Journal of Solid State Electrochemistry》2011,15(9):2031-2039
Ag and Ag2O thin films have been prepared by radio frequency magnetron sputtering on Cu substrates and have been characterized by X-ray
diffraction, scanning electron microscope and atomic force microscope. The electrochemical performance of the thin films has
been studied by galvanostatic cycling and cyclic voltammetry. The potential dependence of Li-ion chemical diffusion coefficients,
[(D)\tilde]\textLi {\widetilde{D}_{\text{Li}}} , of the films has been determined by galvanostatic intermittent titration technique and electrochemical impedance spectroscopy.
It is found that Li-ion chemical diffusion coefficients of the Ag film range from 10−16 to 3 × 10−14 cm2 s−1. The Ag/Li2O composite that is formed from Ag2O after the first cycle exhibits higher
[(D)\tilde]\textLi {\widetilde{D}_{\text{Li}}} values than the Ag film, especially at a low Li-intercalation content. The phase transitions in the two-phase region cause
a significant decrease of chemical diffusion coefficients. 相似文献
27.
Naoyuki Masuda Osamu Yamamoto Masahiro Fujii Tetsuro Ohgami Ayako Moritomo Toru Kontani 《合成通讯》2013,43(17):2305-2316
Various N‐3‐alkylated thiazolidenesulfonamide derivatives were efficiently prepared by the direct endo‐selective alkylation of thiazolylsulfonamides. The effects of different bases and solvents were investigated, and the NaH–THF combination was found to be the most effective at conferring high yields and endo‐selectivity. 相似文献
28.
Yiliang Wu Jun-Ichi Mamiya Osamu Tsutsumi Akihiko Kanazawa Takeshi Shiono Tomiki Ikeda 《Liquid crystals》2013,40(6):749-753
Photoinduced alignment in a polymer liquid crystal prepared from 6-{1-[4-(2-cyano-4-nitrophenylazo)phenyl]piperazino}hexyl acrylate and 4'-[6-(methacryloyloxy)hexyloxy]-4-cyanobiphenyl was investigated for the first time on irradiation with a polarized He-Ne laser beam at 633 nm. The azobenzene moieties as well as the inert cyanobiphenyl mesogenic units were aligned with the molecular long axis perpendicular to the polarization direction of the irradiation light. Alignment induced on short irradiation was reversible, while that induced under prolonged irradiation was irreversible due to the occurrence of crosslinking which might be caused by photoinduced decomposition of the azobenzene moieties during the photoirradiation process. 相似文献
29.
Yusuke Fukahori Yohei Takayama Takuya Imaoka Dr. Osamu Iwamoto Prof. Dr. Kazuo Nagasawa 《化学:亚洲杂志》2013,8(1):244-250
We present a diastereoselective synthesis of disubstituted cyclopentane 8 having a nitrogen‐containing quaternary carbon center, which is found in axinellamine A ( 5 ) and related compounds. During this work, we found that the 1,3‐dipolar cycloaddition product 24 immediately underwent intramolecular redox reaction at the newly formed morpholin‐2‐one moiety, thus affording disubstituted cyclopentane containing a tertiary amine ( 9 ) stereoselectively in good yield. The amine 9 was successfully converted into guanidine 31 , which corresponds to 8 , through iminium cation–enamine isomerization. 相似文献
30.
Atula S.D. Sandanayaka Hisahiro Sasabe Toshikazu Takata Osamu Ito 《Journal of Photochemistry and Photobiology, C: Photochemistry Reviews》2010,11(2-3):73-92
The photosensitized electron-transfer processes in the rotaxane hybrids composed with electron-accepting fullerenes and various electron-donors placed in the rotaxanes are revealed with time-resolved fluorescence and absorption spectral methods. Porphyrins are most useful as light-harvesting donors and photosensitizing donors. In addition, aromatic amines and ferrocene act as electron-donor and also hole-shifting reagents in multi-component rotaxanes. In the rotaxanes with spatially placed donor-acceptor molecules, the role of triplet states becomes important compared with the covalently connected donor–acceptor molecular systems, which may be related to the “through-space” and “through-bond” electron transfer, respectively. In the designed multi-component rotaxanes which maintain mechanically or topologically the electron-acceptor, electron-donor, and hole-shifter, the photoinduced electron transfer, hole-shift, electron–hole recombination are established. As a whole, contribution of the triplet excited states is prominent compared with the covalently bonded molecules and supramolecular systems constructed with coordination bonds. 相似文献