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81.
Liquid surface curvature variations in microplate wells due to different liquid surface tension cause significant signal change in spectroscopic measurement using a plate reader with a vertical detecting light beam. The signals have been quantitated and used to develop a method for facile surfactant critical micelle concentration determination. 相似文献
82.
Viktor S. Burakov Andrey V. Butsen Volker Brüser Falk Harnisch Pulat Y. Misakov Elena A. Nevar Miriam Rosenbaum Natalie A. Savastenko Nikolai V. Tarasenko 《Journal of nanoparticle research》2008,10(5):881-886
Tungsten carbide nanopowder was prepared via pulsed discharge of bulk tungsten and graphite rods immersed in pure ethanol.
The effect of discharge parameters on the characteristics of final products was investigated. Structural and morphological
characterization of nanopowder was performed by means of X-ray diffraction analysis and transmission electron microscopy.
In order to determine the feasibility of using synthesized material as an electrocatalyst, tungsten carbide nanopowder was
tested for hydrogen evolution. A correlation was found between morphology of nanoparticles, their phase composition and electrocatalytic
activity. 相似文献
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Amiram Braun 《Israel Journal of Mathematics》1982,43(2):116-128
LetR=F{x
1, …, xk} be a prime affine p.i. ring andS a multiplicative closed set in the center ofR, Z(R). The structure ofG-rings of the formR
s is completely determined. In particular it is proved thatZ(R
s)—the normalization ofZ(R
s) —is a prüfer ring, 1≦k.d(R
s)≦p.i.d(R
s) and the inequalities can be strict. We also obtain a related result concerning the contractability ofq, a prime ideal ofZ(R) fromR. More precisely, letQ be a prime ideal ofR maximal to satisfyQϒZ(R)=q. Then k.dZ(R)/q=k.dR/Q, h(q)=h(Q) andh(q)+k.dZ(R)/q=k.dz(R). The last condition is a necessary butnot sufficient condition for contractability ofq fromR. 相似文献
86.
87.
The diamagnetic complex [Re(CN)8]3- is shown to react with Mn2+ ions in methanol to generate the centered, face-capped octahedral cluster (CH3OH)24Mn9Re6(CN)48, which is structurally analogous to (CH3OH)24Mn9Mo6(CN)48. Related reactions involving stoichiometric mixtures of octacyanometalate complexes generate the substituted species (CH3OH)24Mn9Mo5Re(CN)48, (CH3OH)24Co9Mo5Re(CN)48, (CH3OH)24Mn9Mo3Re3(CN)48, (CH3OH)24Mn9W5Re(CN)48 and (CH3OH)24Co9W5Re(CN)48, in which the O(h) symmetry of the cluster core is broken. Reassessment of the magnetic properties of the Mn9Mo6(CN)48 cluster confirm that it possesses a ground state spin of S = 39/2, but does not exhibit single-molecule-magnet behavior. Lowering the symmetry of the molecule by substitutions of ReV at one or three of the MoV sites does not lead to an overall increase in the magnetic anisotropy, as probed by ac magnetic susceptibility measurements. A similar result occurs for the other substituted species, with the important exception of the new single-molecule magnet (CH3OH)24Co9W5Re(CN)48, for which the spin reversal barrier is significantly reduced relative to that observed previously in (CH3OH)24Co9W6(CN)48. 相似文献
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90.
Martínez-Martín D Jaafar M Pérez R Gómez-Herrero J Asenjo A 《Physical review letters》2010,105(25):257203
In this work we investigate possible ferromagnetic order on the graphite surface by using magnetic force microscopy (MFM). Our data show that the tip-sample interaction along the steps is independent of an external magnetic field. Moreover, by combining kelvin probe force microscopy and MFM, we are able to separate the electrostatic and magnetic interactions along the steps obtaining an upper bound for the magnetic force gradient of 16 μN/m. Our experiments suggest the absence of ferromagnetic signal in graphite at room temperature. 相似文献