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51.
Kouhei Hatanaka Shigeo Tanimoto Toyonari Sugimoto Masaya Okano 《Tetrahedron letters》1981,22(34):3243-3244
It has been found that the reaction of enol silyl ethers with 2-ethoxy-1,3-dithiolane proceeds smoothly in the presence of zinc chloride catalyst to afford half-protected 1,3-dicarbony1 compounds in moderately good yields. 相似文献
52.
Some optical differential interferometric techniques were investigated in order to measure the density distribution in the air jet flow of a small scale flow cell while excluding the effects of the optical distortion of its glass windows. A technique using moiré fringe formation by rotating the reference wave in one exposure of the double exposure method was found to be most suitable for this purpose. High contrast and multiplication of moiré fringes can be obtained by a moiré fringe sharpening and multiplication method. 相似文献
53.
Hikita M Tanaka K Nakamura T Kajiyama T Takahara A 《Langmuir : the ACS journal of surfaces and colloids》2004,20(13):5304-5310
Well-defined poly(styrene-block-2-perfluorooctyl ethyl acrylate) [P(St-b-PFA)] copolymers with various chemical compositions were synthesized by atom transfer radical polymerization. Films of P(St-b-PFA) were structurally characterized, from bulk to surface, on the basis of transmittance electron microscopic observation and small-angle X-ray scattering, X-ray photoelectron spectroscopic, and contact angle measurements. For a comparison, poly(styrene-random-2-perfluorooctyl ethyl acrylate) [P(St-ran-PFA)] copolymers were also synthesized by conventional free radical polymerization. While P(St-b-PFA) with the 2-perfluorooctyl ethyl acrylate (PFA) content higher than 18.7 mol % formed a typical phase-separated cylinder structure, P(St-b-PFA) with a lower PFA content and P(St-ran-PFA) were in a miscible state. Since the perfluoroalkyl groups possess extremely low surface energy, they were preferentially segregated at the film surface, resulting in the formation of the PFA surface layer. This was the case for all P(St-b-PFA) films examined, although the aggregation state at the surface was strongly dependent on the PFA content. In the case of the P(St-b-PFA) with the PFA content higher than 18.7 mol %, both advancing and receding contact angles for water were 120 degrees and even larger with almost no hysteresis. In addition, extremely excellent oil-repellent surface properties such as advancing and receding contact angles for dodecane of 76 degrees and 75 degrees were also observed. However, these intriguing liquid-repellent properties were not observed for the films of miscible P(St-b-PFA) and P(St-ran-PFA). Therefore, it can be concluded that the internal structure beneath the surface as well as the surface itself should be deeply considered to design excellent and stable liquid-repellent materials. 相似文献
54.
Matsuo Y Tahara K Sawamura M Nakamura E 《Journal of the American Chemical Society》2004,126(28):8725-8734
Selective penta-addition of a methylcopper reagent followed by addition of a phenylcopper reagent to a suitably modified synthetic intermediate results in creation of 40pi-electron systems-hoop- and bowl-shaped cyclic benzenoid compounds, [10]cyclophenacene, and dibenzo-fused corannulene derivatives. The 40pi-electron cyclophenacene derivatives have been found to be chemically stable, yellow-colored, luminescent (560 nm), and EPR-silent. X-ray crystallographic analysis provided precision structural data sets. The dibenzo-fused corannulene derivatives exhibit blue-green (460 nm) to red (649 nm) fluorescence. 相似文献
55.
Matsui J Mitsuishi M Aoki A Miyashita T 《Journal of the American Chemical Society》2004,126(12):3708-3709
We describe here a polymer nanosheet assembly that serves as a molecular photoswitching and optical exclusive OR (EXOR) logic gate. Separate polymer nanosheets (monolayers) containing phenanthrene, anthracene, and dinitrobenzene chromophore were prepared by the Langmuir-Blodgett technique (LB films). A bilayer-couple, consisting of phenanthrene (sensitizer) monolayer and dinitrobenzene (acceptor) monolayer, and the other couple, of anthracene monolayer and dinitrobenzene monolayer, were confirmed to function as a photodiode showing current rectification on light irradiation. The two photodiodes are connected as each photocurrent direction becomes opposite. In the polymer photodiode array (LB films), anodic photocurrent was observed when the anthracene was selectively excited. On the other hand, cathodic photocurrent was observed by selective excitation of the phenanthrene. Moreover, the output photocurrent displayed a very small value when the phenanthrene and anthracene were excited simultaneously. The performance is discussed for this gate's application to an optical EXOR logic gate. 相似文献
56.
Nakazawa J Yajima J Usui T Ueki M Takatsuki A Imoto M Toyoshima YY Osada H 《Chemistry & biology》2003,10(2):131-137
To reveal the mechanism of mitosis, the development of M phase-specific inhibitors is an important strategy. We have been screening microbial products to find specific M phase inhibitors that do not directly target tubulins, and rediscovered terpendole E (TerE) as a novel Eg5 inhibitor. TerE did not affect microtubule integrity in interphase, but induced formation of a monoastral spindle in M phase. TerE inhibited both motor and microtubule-stimulated ATPase activities of human Eg5, but did not affect conventional kinesin from either Drosophila or bovine brain. Although terpendoles have been reported as inhibitors of acyl-CoA:cholesterol O-acyltransferase (ACAT), the Eg5 inhibitory activity of TerE was independent of ACAT inhibition. Taken together, we demonstrate that TerE is a novel Eg5 inhibitor isolated from a fungal strain. 相似文献
57.
58.
T.M. Nakatani Y.K. Takahashi M. Yamamoto 《Journal of magnetism and magnetic materials》2010,322(3):357-361
We have investigated the structure of Co2MnSi/MgO/Co2MnSi magnetic tunneling junctions with different tunnel magnetoresistance values depending on the in situ annealing temperatures just after the deposition of the upper Co2MnSi electrodes. The nano-beam diffraction patterns indicated that the degree of order of the upper Co2MnSi electrode annealed at 550 °C was higher than that of an electrode annealed at 400 °C. Moreover, the degree of the L21 order of the upper Co2MnSi electrode annealed at 550 °C was even lower than that of the lower Co2MnSi electrode annealed at an almost equal temperature of 600 °C. Atomic-scale observation using a high-angle annular dark-field (HAADF) method distinctly showed the existence of the L21-ordered regions in the B2-ordered matrix in the upper Co2MnSi electrode annealed at 400 °C. 相似文献
59.
60.
Iron mixed-valence complex, (n-C3H7)4N[FeIIFeIII(dto)3] (dto = C2O2S2) shows a new-type of phase transition coupled with spin and charge around 120 K, where the charge transfer between the FeII and FeIII sites occurs reversibly, and shows the ferromagnetic transition at 7 K. To investigate the magnetic structure and its dimensionality of (n-C3H7)4N[FeIIFeIII(dto)3], we have synthesized a mixed crystal system, (n-C3H7)4N[FeII1?xZnIIxFeIII(dto)3], and measured its magnetic properties. In this system, the magnetic moment is reduced with increasing of Zn ratio. Moreover, the ferromagnetic interaction changes to the antiferromagnetic one and the remnant magnetization disappears between x = 0.48 and 0.96, while the charge transfer between the FeII and FeIII sites disappears above x = 0.26. In this paper, we present the magnetic dilution effect on the charge transfer phase transition and the ferromagnetic transition by means of magnetic susceptibility measurement and 57Fe Mössbauer spectroscopy. 相似文献