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排序方式: 共有881条查询结果,搜索用时 31 毫秒
821.
Katsuya Ichihashi Daisuke Konno Kseniya Yu. Maryunina Katsuya Inoue Kazuhiro Toyoda Shogo Kawaguchi Yoshiki Kubota Yoko Tatewaki Tomoyuki Akutagawa Takayoshi Nakamura Sadafumi Nishihara 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(13):4213-4216
Artificial ion channels are of increasing interest because of potential applications in biomimetics, for example, for realizing selective ion permeability through the transport and/or exchange of selected ions. However, selective ion transport and/or exchange in the crystalline state is rare, and to the best of our knowledge, such a process has not been successfully combined with changes in the physical properties of a material. Herein, by soaking single crystals of Li2([18]crown‐6)3[Ni(dmit)2]2(H2O)4 ( 1 ) in an aqueous solution containing K+, we succeeded in complete ion exchange of the Li+ ions in 1 with K+ ions in the solution, while maintaining the crystalline state of the material. This ion exchange with K+ was selectively conducted even in mixed solutions containing K+ as well as Na+/Li+. Furthermore, remarkable changes in the physical properties of 1 resulted from the ion exchange. Our finding enables not only the realization of selective ion permeability but also the development of highly sensitive biosensors and futuristic ion exchange agents, for example. 相似文献
822.
This paper describes flow and heat transfer characteristics of laminar mixed-convection flows of water with sub-millimeter bubbles in a vertical channel. We use thermocouples and a particle tracking velocimetry technique for the temperature and velocity measurements. The working fluid used is tap water, and hydrogen bubbles generated by electrolysis of the water are used as the sub-millimeter bubbles. The Reynolds number of the main flow ranges from 100 to 200. The ratio of the heat transfer coefficient with sub-millimeter-bubble injection to that without injection (the heat transfer coefficient ratio) ranges from 1.24 to 1.38. The heat transfer coefficient ratio decreases with the increase in the Reynolds number. We conclude from velocity measurements that this decrease is mainly caused by a decrease in the advection effect due to sub-millimeter bubbles. 相似文献
823.
Katsuya Nagayama Toshimasa Tanaka Kazuhiro Tanaka Hiroshi Hayami Shinichiro Aramaki 《Experiments in fluids》2008,44(5):843-850
Loach has a unique swimming style of bending the whole body and staying at the bottom of water. We studied the three-dimensional
flow field around and behind the loach using stereoscopic-PIV. We captured flow fields in horizontal and vertical plane, and
it seems loach leaves vortex tube arches. From the analysis of body motion and flow field, we propose flow structure with
vortex tube arches connected along the loach body. After being released, they are separated and flow away and dissipate.
This research article was submitted for the special issue on Animal locomotion: The hydrodynamics of swimming (Vol. 43, No.
5). 相似文献
824.
Taconis oscillation in a closed long tube with large thermal gradient is studied by numerical calculation of the 2D compressible Navier-Stokes equations. The both ends of tube are hot (T = TH), and the center of side wall is cold (T = TC). We analyze the pressure amplitude pamp and the time averaged temperature Tm in the closed tube. pamp is almost homogenous in the tube cross section, however, Tm is not homogenous in the central cold region. We also observe two steady states at the same temperature ratio θ = TH/TC. It is important to analyze the effects of the boundary layer in this cold region on Taconis oscillations. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
825.
Ichiro Oda 《Physics letters. [Part B]》2000,480(3-4):305-311
We construct a new model with exponential mass hierarchy by starting with the Einstein–Hilbert action with the cosmological constant in five dimensions plus an action describing many domain walls in four dimensions. The model includes many hidden sectors and one visible sector, and each four-dimensional domain wall, that is, 3-brane, interacts with one another through only a gravitational interaction and realizes many universe cosmology inspired by D-brane perspective. It is shown that in the present model only even numbers of domain walls are allowed to locate in five dimensional space-time and the validity of Randall–Sundrum scenario, which explains mass hierarchy between the Planck mass and the electro-weak scale in our world, depends on a relative relation between our world and hidden worlds. 相似文献
826.
Nakao Y Yukawa T Hirata Y Oda S Satoh J Hiyama T 《Journal of the American Chemical Society》2006,128(22):7116-7117
Allyl cyanides are found to add across alkynes in the presence of a nickel catalyst prepared from Ni(cod)2 and P(4-CF3-C6H4)3 in situ to give variously functionalized di- or trisubstituted acrylonitriles in highly stereoselective manners possibly via a pi-allylnickel species as an intermediate. alpha-Siloxyallyl cyanides also react at the gamma-position of a cyano group with both internal and terminal alkynes having various functional groups to give silyl enol ethers, which give the corresponding aldehydes or ketones upon hydrolysis. 相似文献
827.
Hideo?SawadaEmail author Ayumu?Sasaki Kazuo?Sasazawa Tokuzo?Kawase Katsuya?Ueno Kazuo?Hamazaki 《Colloid and polymer science》2005,283(5):583-586
Nanometer size-controlled gold particles were prepared under mild conditions by reducing the corresponding metal precursor in the presence of self-assembled molecular aggregates formed by fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomers. The stable gold nanoparticles protected by these fluorinated molecular aggregates were applied to the dispersion above the poly(methyl methacrylate) film surface. 相似文献
828.
Mixing behavior of hydrogenated and fluorinated cationic gemini surfactants was studied at the air-water interface by Brewster angle microscopy and pi-A isotherm curves. In the bulk, these two molecules did not mix and showed phase separation. At the air-water interface, if a monolayer was formed by separate deposition of the two solutions, they formed separate domains, and the compression occurred in two steps: first the domains with hydrogenated gemini surfactant were compressed until they showed collapse; then the domains with fluorinated gemini surfactant were compressed. If the two solutions were mixed before the deposition, they remained mixed upon compression; on the other hand, separate domains under separate deposition were shown to mix if the subphase was heated. 相似文献
829.
830.
Treatment of 9-chloro-9-phenylbicyclo[6.1.0]nona-2,4,6-triene with excess bases gives, by the intermediacy of 9-phenylbicyclo[6.1.0]-1-(9),2,4,6-tetraene, 9-phenylbicyclo[6.1.0]tetraenyl anion of which 1H-NMR spectrum suggests some diatropic character of the molecule. 相似文献