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991.
报道了趋磁细菌WD-1琥珀酸脱氢酶、呼吸抑制剂NaN3、解偶联剂DNP对磁小体合成的影响.琥珀酸脱氢酶活性高,磁小体合成能力强,每个细胞所含磁小体数量多;1mmolL-1NaN3或1mmolL-1DNP能抑制WD-1的好氧生长,10mmolL-1NaN3不抑制WD-1的微好氧生长,但1mmolL-1DNP明显地影响微好氧生长,即生长缓慢.WD-1在微好氧、好氧、好氧与0.01~0.10mmolL-1NaN3(或DNP)的培养条件下生长时,磁小体合成能力依次下降 相似文献
992.
Several levels of approximation are investigated to account for the effect of small fatigue cracks on the residual strength of aircraft sheet materials and fuselage lap joints containing major cracks. A version of the Dugdale model is proposed which accounts for strain hardening of the sheet in an approximate way and which incorporates a criterion for crack advance leading to crack growth resistance. This model builds upon the model proposed by Nilsson and Hutchinson [1] and accounts for the detailed interaction between the major crack and the small damage cracks. A simpler version of the model uses the damage-reduced local strength of the sheet or joint in assessing the effect of the major crack on residual strength. The simpler approach thus bypasses the necessity of a direct determination of the highly complicated details of the interaction of the small cracks in a lap joint with a major crack. 相似文献
993.
利用量子对称群的概念,我们给出U_q(sl_n)-多项式、U_q(sl_n)-外积的定义,说明U_q(sl_n)的q-振子、q-旋量表示不过是U_q(sl_n)标准表示的量子对称、量子反称张量积,这和经典情形是一致的。 相似文献
994.
Co(Ⅱ),Ni(Ⅱ)非有机溶剂液—液萃取行为的研究 总被引:3,自引:0,他引:3
张振新 《光谱学与光谱分析》1998,18(3):381-383
In PEG-Eriochrome cyanine R-(NH4)2SO4 system the liquid-liquid extraction behaviour of Co(II) and Ni(II) without organic solvents was investigated. We found that Ni(II) was almost extracted by PEG phase while Co(II) was not extracted in the water solutions of NaAc-HAc (pH=5) and (NH4)2SO4. Thus Co(II) was quantitatively separated from mixed solutions of Ni(II) and Co(II) ions. 相似文献
995.
996.
2-Cyclopenten-1-one-5-carboxylic ester derivatives 14 are synthesized in a four-step-reaction sequence starting from alkynyl aldehydes 9 via 4Z-β-vinyl-α-diazo β-ketoesters intermediate 8. The synthetic method for 8 is described. When the δ substituent is an alkyl group, Rh(II)-mediated decomposition of the diazo compounds 8 led to an intramolecular C-H insertion to afford 2-cyclopenten-1-one-5-carboxylic ester derivatives 14 in high yields. When the δ substituent is an aryl group, 2-hydroxynaphthoate 15 is obtained exclusively. In both cases, no Wolff rearrangement product was observed. 相似文献
997.
998.
Gold nanoparticle multilayers were self-assembled onto an electrode surface by using a dipping method. The particle assemblies exhibited quantized capacitance charging characteristics in aqueous media that were rectified by hydrophobic anions such as PF6-, BF4- and ClO4-, similar to the behavior with the monolayer counterparts. More interestingly, even in the presence of less hydrophobic anions such as NO3-, very well-defined single electron transfers were observed voltammetrically with these particle multilayers, a response unseen previously with particle monolayers. This was ascribed, in part, to the enhanced interactions between the particle multilayers and the electrolyte anions as well as the minimization of the structural defects within the particle thin films as compared to the monolayer counterparts. Further studies showed that with particles functionalized with oligo(ethylene oxide) moieties, the particle charge transfer properties were also found to be affected by electrolyte cations, reflected by the variation of the particle molecular capacitance and formal potentials with the nature of the alkaline (earth) metal ions. 相似文献
999.
Let G be a bipartite graph with vertex set V(G) and edge set E(G), and let g and f be two nonnegative integer-valued functions defined on V(G) such that g(x) ≤ f(x) for every vertex x of V(G). A (g, f)-coloring of G is a generalized edge-coloring in which each color appears at each vertex x at least g(x) and at most f(x) times. In this paper a polynomial algorithm to find a (g, f)-coloring of a bipartite graph with some constraints using the minimum number of colors is given. Furthermore, we show that
the results in this paper are best possible. 相似文献
1000.
Carboxylation of lithium trialkylalkynylborate can take place under favourable conditions. Protonation of the reaction product yields (Z)-α,β-unsaturated acid. 相似文献