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61.
Stable conformations of 12-crown-O3N and its Li complexes in aqueous solution were investigated. To calculate the free energy differences of conformers of 12-crown-O3N and its Li+ complex, our procedure was to make use of two programs, CONFLEX and BOSS. The former generates conformers, and the latter calculates the differences in free energy of solvation between two conformers in aqueous solution. It was confirmed that the present procedure is applicable in solving the question of what is the most stable conformation of 12-crown-O3N in aqueous solution. Results of the calculations suggest that the order of stability for conformers in a vacuum is different from that in aqueous solution. It was also confirmed that the coordination geometry of solvent waters to Li+ changes depending on the distance between the cation and the crown ring. 相似文献
62.
Uto Y Hirata A Fujita T Takubo S Nagasawa H Hori H 《The Journal of organic chemistry》2002,67(7):2355-2357
We have demonstrated that prenylation of p-halophenols was dependent on the solvent effect and succeeded in o,o'-diprenylation of p-halophenols in water. Following the Mizoroki-Heck coupling of the diprenyl-p-iodophenol 3c with methyl acrylate and then hydrolysis, we first synthesized artepillin C [3-(4-hydroxy-3,5-di(3-methyl-2-butenyl)phenyl)-2(E)-propenoic acid] (1), which is a biologically active constituent of propolis. These reactions may be applicable to the synthesis of various useful natural products such as 2,4,6-trisubstituted phenol derivatives. 相似文献
63.
Widmann E Eades J Ishikawa T Sakaguchi J Tasaki T Yamaguchi H Hayano RS Hori M Torii HA Juhász B Horváth D Yamazaki T 《Physical review letters》2002,89(24):243402
Using a newly developed laser-microwave-laser resonance method, we observed a pair of microwave transitions between hyperfine levels of the (n,L)=(37,35) state of antiprotonic helium. This experiment confirms the quadruplet hyperfine structure arising from the interaction of the antiproton orbital angular momentum, the electron spin and the antiproton spin as predicted by Bakalov and Korobov. The measured frequencies of nu(+)(HF)=12.895 96+/-0.000 34 GHz and nu(-)(HF)=12.924 67+/-0.000 29 GHz agree with recent theoretical calculations on a level of 6x10(-5). 相似文献
64.
Hori M Eades J Hayano RS Ishikawa T Sakaguchi J Tasaki T Widmann E Yamaguchi H Torii HA Juhász B Horváth D Yamazaki T 《Physical review letters》2002,89(9):093401
Initial distributions of metastable antiprotonic (4)He and (3)He atoms over principal (n) and angular momentum (l) quantum numbers have been deduced using laser spectroscopy experiments. The regions n = 37-40 and n = 35-38 in the two atoms account for almost all of the observed fractions [(3.0 +/- 0.1)% and (2.4 +/- 0.1)%] of antiprotons captured into metastable states. 相似文献
65.
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67.
Matsunaga S Watanabe S Sakaushi S Miyamura S Hori T 《Photochemistry and photobiology》2003,77(3):324-332
We found diaphototactic behavior (i.e. the cells swim perpendicularly with respect to the incident light) in a strain with colorless eyespot of a unicellular disk-shaped green flagellate Mesostigma viride. Lacking pigments completely in the eyespot, the screening effect in this strain was due only to the central part of the chloroplast whose cross section was thin. The diaphototaxis was most obvious when unilateral green stimulus light (520-580 nm) was given, whereas positive phototaxis appeared when given blue light (430-490 nm). The choice between diaphototaxis and (ordinary) phototaxis depended entirely on the transmission (%T) of the cell body against each wavelength of the stimulus: the green light penetrated well (%T > 90%), whereas the blue light was considerably shaded by the chloroplast (50% < %T < 70%). The fraction of positive phototactically behaving cells against each wavelength was in proportion to the front-to-back contrast value obtained at each individual wavelength. The fraction of diaphototaxis was inversely proportional to it. In addition, bilateral stimulus irradiations to wild-type cell with colored eyespot provided useful information about the principle of the diaphototactic steering. 相似文献
68.
In reactive plasma processing, species produced in the plasma reach the surface of a substrate and cause etching, deposition and surface modification through surface reactions. These reactions are characterized by the densities and energies of species incident on the surfaces. In order to realize nano-scale plasma processing, important species for plasma processing have been identified and characterized, and their behavior, not only in the gas phase, but also on the surface, have been clarified and controlled. One of the most critical parameters for insights into surface reaction kinetics of radicals is sticking and surface loss probability. On the basis of radical densities measured by various methods, the sticking and surface reaction loss probabilities have been compiled, and they enable the quantitative understanding of the kinetics of radicals on the surface in the plasma. In this article, the sticking and surface reaction loss probabilities measured thus far are reviewed focusing on fluorocarbon gas, silane gas and methane gas based plasma processes. The establishment of a smart plasma process and the development of an autonomous production device with control of radicals on the basis of insights into the surface reactions for nano-scale plasma processing are presented. 相似文献
69.
Kinichi Obi Yutaka Matsumi Yasuaki Takeda Shinya Mayama Hajime Watanabe Soji Tsuchiya 《Chemical physics letters》1983,95(6):520-524
The new nozzle assembly using Hg-photosensitized reaction has been developed to obtained a jet-cooled radical beam. This technique was applied to produce a HNO radical beam. Laser-induced flourescence excitation spectra were obtained for the 1A″ — 1A′ system. Time-resolved measurements yielded fluorescence lifetimes of 22–29 μs for single rovibronic levels of HNO. 相似文献
70.
Okitsu K Suzuki T Takenaka N Bandow H Nishimura R Maeda Y 《The journal of physical chemistry. B》2006,110(41):20081-20084
Acoustic cavitation generates transient microbubbles with extremely high temperatures and high pressures, which can provide unique reaction routes. The maximum bubble temperature attained is widely known to be dependent on the polytropic index and thermal conductivity of the dissolved gas. Here, we show for the first time experimental evidence that the bubble temperature induced by a high frequency ultrasound is almost the same among different rare gases and the chemical efficiency is in proportion to the gas solubility of rare gases, which would be closely related to the number of active bubbles. 相似文献