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811.
Takahashi S Miura H Kasai H Okada S Oikawa H Nakanishi H 《Journal of the American Chemical Society》2002,124(37):10944-10945
Topochemical [2 + 2] cycloaddition polymerization of methyl p-phenylenediacrylate and 2,5-distyrylpyridine in nanocrystals, prepared by the reprecipitation method, were investigated in comparison with those in bulk crystals. The bulk single crystals, larger than 1 mum in size, broke into microcrystals with variety of size and shape in the course of polymerization. Interestingly, however, these nanocrystals show single-crystal-to-single-crystal transformation. 相似文献
812.
Lee SS Ahn JR Kim ND Min JH Hwang CG Chung JW Yeom HW Ryjkov SV Hasegawa S 《Physical review letters》2002,88(19):196401
We find that foreign adsorbates acting as local impurities can induce a metal-insulator transition by pinning a charge-density wave (CDW) on the quasi-1D metallic In/Si(111)-(4x1) chain system. Our scanning tunneling microscopy image clearly reveals the presence of a new local 4x2 structure nucleated by Na adatoms at room temperature, which turns out to be insulating with a doubled periodicity along the chains. We directly determine a CDW gap energy Delta = 105+/-8 meV by identifying a characteristic loss peak in our high-resolution electron-energy-loss spectra. We thus report the first observation of a local impurity-derived Peierls-like reconstruction of a quasi-1D system. 相似文献
813.
814.
Shuji Saito 《Colloid and polymer science》1954,137(2-3):93-98
Zusammenfassung Die Polyelektrolyten (Polyakryls?ure, Carboxymethylzellulose, K-Polyvinylsulfat) verhalten sich bei Zusatz gleichnamig geladener
Netzmittel anders als bei Zusatz des einfachen Salzes, was durch die Analogie der Wechselwirkung zwischen Netzmittel und nichtionischen
Polymeren wie Polyvinylalkohol zu erkl?ren ist. 相似文献
815.
816.
J Adachi Y Mizoi T Naito K Yamamoto S Fujiwara I Ninomiya 《Journal of chromatography. A》1991,538(2):331-339
A high-performance liquid chromatographic method combined with fluorimetric detection is described for the determination of beta-carboline (norharman) and 1-methyl-beta-carboline (harman). The analysis of foodstuffs for the identification of beta-carbolines is facilitated by clean-up samples using Bond Elut PRS cartridges. Recoveries were excellent. Further, a high-performance liquid chromatographic-mass spectrometric method was also developed for their identification. The concentration of beta-carboline among the foodstuffs and alcoholic beverages varied greatly. Also, norharman and harman were observed in uncooked foodstuffs, whereas acetaldehyde was found in most fermented food. The toxicological implication of beta-carbolines in foodstuffs is discussed. 相似文献
817.
Shuji Takahashi 《manuscripta mathematica》1990,69(1):237-254
We are concerned with the behavior of weak solutions of the Navier-Stokes equations near possible singularities. We shall
show that if a weak solution is in some Lebesgue space or small in some Lorentz space locally, it does not blowup there. Our
basic idea is to estimate integral formulas for vorticity which satisfies parabolic equations. 相似文献
818.
819.
The high-energy pire-leptonic weak interaction is investigated based on the assumption of the existence of a charged vector boson which mediates the weak processes. With the aid of the fixed-t dispersion relation the following relation is obtained: The weak boson mass mW should satisfy , with G the Fermi coupling constant, if the asymptotic value of the cross section becomes of the order of the strong interaction in the energy region observable in cosmic rays, etc.The scattering processes are examined by the aid of the N/D method. For a large vector-boson mass , an S-wave resonance should exist for the process e+ν→e+ν while for there should exist a P-wave resonance which corresponds to the intermediate weak boson. The neutral current is then estimated. It is shown that the neutral current produced as a higher-order effect is not inconsistent with the present experiments on the pure-leptonic weak interaction if mW?1 TeV. 相似文献
820.