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61.
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T. Katriňák 《Algebra Universalis》1994,31(4):475-491
Presented by J. Berman. 相似文献
63.
64.
Katri Laihia Jaakko Paasivirta Heikki Pikkarainen Sirkku Aho-Pulliainen 《Magnetic resonance in chemistry : MRC》1984,22(2):117-120
The 13C NMR spectra of nine dichlorinated bicyclo[2.2.1]heptanes (norbornanes) have been measured and assigned. The pairwise effects of chlorine substituents which cause deviations from the additivity of single-substituent effects were investigated and are discussed. The largest effect found is the high-field shift of carbons bearing vicinal cis substituents. In the case of geminal substitution deviations from additivity were found to be to low field and large in the γ, smaller in the β and negligible in the α chemical shifts. The observed deviations for 1,3-disubstituted cases vary from ?3.2 to +1.1 ppm at different carbons, allowing no simple explanation. Replacement of α-hydrogen in a diaxial 1,3-arrangement by CH3, OH or CI causes the single substituent effect, namely the γa effect, to change considerably. 相似文献
65.
Gilberto Maia Fernando C. Maschion Sônia T. Tanimoto Katri Vaik Uno Mäeorg Kaido Tammeveski 《Journal of Solid State Electrochemistry》2007,11(10):1411-1420
The electrochemical reduction of oxygen on glassy carbon (GC) electrodes modified with anthraquinones was studied using cyclic
voltammetry (CV) and the rotating disk electrode (RDE) technique. Two methods were used in surface modification. The first
method comprised immersion of the polished or anodically pretreated GC electrode in a solution containing 9,10-anthraquinone-2-carboxylic
acid (AQ-2-COOH) or its anion (AQ-2-COO−) in dimethylsulfoxide (DMSO) or 9,10-anthraquinone-2-ethanoic acid (AQ-2-CH2COOH) or its anion (AQ-2-CH2COO−) in N,N-dimethylformamide (DMF). Alternatively, the surface of the GC disk was modified by anodic oxidation of AQ-2-COOH or AQ-2-COO− in DMSO or AQ-2-CH2COOH in DMSO or DMF or AQ-2-CH2COO− in DMF. The modified electrodes showed electrocatalytic activity toward oxygen reduction in 0.1 M acetate buffer pH (4.8),
0.1 M phosphate buffer (pH 8) and 0.1 M NaOH. Atomic force microscopy (AFM) examination of the modified electrodes was carried
out and the differences in surface morphology of various modifications were in evidence. 相似文献
66.
Rosenthal-Aizman K Svensson G Undén A 《Journal of the American Chemical Society》2004,126(11):3372-3373
Cyclic peptides with alternating d- and l-amino acid residues containing tert-leucine residues in every second position can form peptide nanotubes only when both enantiomers of the peptide are present in the solution. These results strongly indicate the formation of peptide nanotubes that assemble with one enantiomer in every second position, thereby forming a lamellar structure. 相似文献
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We study the gauge coupling unification with extra dimensions. We take into account corrections due to the higher dimensional operators. We show the prediction of 3(MZ) is sensitive to such corrections, even if cΦ/M=O(0.01). We also discuss the b−τ Yukawa unification. 相似文献
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