Electrical resistivity anisotropy from self-organized one dimensionality in high-temperature superconductors

We investigate the manifestation of stripes in the in-plane resistivity anisotropy in untwinned single crystals of La2-xSrxCuO4 ( x = 0.02-0.04) and YBa(2)Cu(3)O(y) ( y = 6.35-7.0). It is found that both systems show strongly temperature-dependent in-plane anisotropy in the lightly hole-doped region and that the anisotropy in YBa(2)Cu(3)O(y) grows with decreasing y below approximately 6.60 despite the decreasing orthorhombicity, which gives most direct evidence that electrons self-organize into a macroscopically anisotropic state. The transport is found to be easier along the direction of the spin stripes already reported, demonstrating that the stripes are intrinsically conducting in cuprates.     

Josephson plasmon and inhomogeneous superconducting state in La2-xSrxCuO4

We report on the interlayer far infrared response for a series of La2-xSrxCuO4 crystals with 0.08相似文献   

Harmonic maps between unbounded convex polyhedra in hyperbolic spaces

Oblatum 20-I-1993 & 19-VII-1993     

ESR study on the photosensitized decomposition of polyethylene

Several aromatic compounds were added to low-density polyethylene to determine their effects on the photodegradation of polyethylene. It was shown that some aromatic compounds indeed sensitize the hydrogen abstraction of the allylic hydrogen of unsaturated groups contained in polyethylene as an improper bond. The mechanism of photosensitization was investigated by an ESR method. It was found that the higher photoexcited triplet state of an aromatic molecule produced by the biphotonic ultraviolet light absorption transfers its excess energy to the unsaturated bond to excite it, and the excited unsaturated group releases its allylic hydrogen atom, giving an allylic radical.     

Stereospecific polymerization of methacrylonitrile. V. Formation of the carbonyl in the polymer

The isotactic polymethacrylonitrile prepared by the organometallic catalysts has carbonyl groups in the polymer. Thus, the carbonyl formation during the polymerization by diethylmagnesium was carefully studied by infrared spectrometry. It was found that the imino anion formed by monomolecular termination of the propagating chain end in the cyclization reaction successively attacks the vicinal pendent nitriles in the polymer so as to form the conjugated cyclic imines, which are hydrolyzed to acid amines during the catalyst decomposition with acidic methanol.     

Ozone Degradation by Fluoride onto Plasma-Treated Activated Carbon in CF4

The ozone degradation of fluorine was investigated using the tetrafluoromethane plasma-treated activated carbon (PT-AC). The ozone in the stratosphere has been degraded by the chloride and bromide radicals which are produced from chlorofluorocarbons and bromofluorocarbons, respectively. However, we believe that fluorine also was related to the ozone degradation. The fluoride was introduced onto the activated carbon surface by tetrafluoromethane plasma treatment. The breakthrough curve of ozone onto PT-AC was measured to elucidate the relationship between the ozone and the fluoride. The amount of ozone adsorbed/degraded onto the PT-AC was larger than the amount that was adsorbed/degraded onto the untreated activated carbon. The amount of fluoride ion eluted from the PT-AC before the adsorption/degradation of ozone was larger than that which eluted after the adsorption/degradation of ozone. These results indicated that the ozone was degraded by the fluoride on the PT-AC surface.     

Transport properties of anion exchange membranes prepared by the reaction of crosslinked membranes having chloromethyl groups with 4‐vinylpyridine and trimethylamine

The electrodialytic transport properties of new anion exchange membranes were evaluated that included the transport numbers of various anions, sulfate, bromide, fluoride, and nitrate ions, relative to chloride ions and current efficiency. The anion exchange membranes were prepared by the reaction of copolymer membranes crosslinked to different extents having chloromethyl groups with 4‐vinylpyridine to form a ladder‐like polymer in the membranes and then with trimethylamine to convert the remaining chloromethyl groups to benzyl trimethylammonium groups. The transport numbers of the sulfate and fluoride ions relative to the chloride ions were markedly less for the membranes that had been reacted with 4‐vinylpyridine and then with trimethylamine compared with those of the membranes that had been reacted only with trimethylamine. On the other hand, the selective permeation of nitrate and bromide ions through the membranes was enhanced by the reaction with 4‐vinylpyridine although the membranes became tighter by the reaction. The decrease in permeation of the sulfate ions was attributed to a synergistic effect involving the decrease in sulfate ions ion‐exchanged with the membranes and the decrease in mobility of the sulfate ions in the membranes with a low degree of crosslinking. Though the ion‐exchanged sulfate ion content was the lowest in the highly crosslinked membranes, the mobility ratio between the sulfate ions and chloride ions did not decrease in the membranes. However, the increase in the permeation of nitrate ions was based on the increase in the ion‐exchanged amount of nitrate ions with the membrane, and not the change in the mobility ratio between the nitrate and chloride ions. The formation of the ladder‐like polymer in the membrane matrix brought on a decrease in the hydrophilicity of the membranes due to pyridine groups and an increase in their tightness. The current efficiency of all membranes was greater than 99% during the electrodialysis of 0.50 N salt solutions. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 1773–1785, 1999     

Magic doping fractions for high-temperature superconductors

We report hole-doping dependence of the in-plane resistivity rho(ab) in a cuprate superconductor La(2-x)Sr(x)CuO4, carefully examined using a series of high-quality single crystals. Our detailed measurements find a tendency towards charge ordering at particular rational hole-doping fractions of 1/16, 3/32, 1/8, and 3/16. This observation appears to suggest a specific form of charge order and is most consistent with the recent theoretical prediction of the checkerboard-type ordering of the Cooper pairs at rational doping fractions x = (2m+1)/2n, with integers m and n.     

亚纯函数的n阶导数分享1值点的唯一性的一些结果

In this paper, we consider the problem of the uniqueness for meromorphic functions whose n-th derivatives share the same 1-points. The results in this paper are different from all of theorems given by H X Yi and C C Yang and other authors.