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991.
992.
Fischer indole cyclization of phenylhydrazine and various ketones using carboxyl-functionalized ionic liquid, 1-carboxymethyl-3-methylimidazolium tetrafluoroborate (abbreviated as [cmmim][BF4]) as catalyst was successfully performed. The yields of thetarget compounds were 80-92%, the purities were 96-98%. The catalyst could be rocovered and reused for at least six times without significant loss in activity. 相似文献
993.
Two new C-glucofuranosyl isoflavones of impurities in puerarin injection were isolated.Their structures were determined to be 8-C-α-glucofuranosyl-7,4'-dihydroxyisoflavone and 8-C-β-glucofuranosyl-7,4'-dihydroxy-isoflavone by chemical and spectral analysis. 相似文献
994.
995.
996.
施用污泥对黑麦草生长及重金属含量的影响 总被引:1,自引:0,他引:1
采用单因素随机区组试验的方法,研究了金华市污水厂污泥堆肥对黑麦草生长和对重金属的吸收及富集的影响。结果表明,施用量以1kg/m^2和2kg/m^2的两个处理为宜,当年的产草量比对照分别增加了22.6%和27.8%;施用污泥黑麦草植株地上部组织重金属元素Pb、Cd和Cu的含量与对照相比无显著差异,Zn的积累量增多,重金属含量均未超过植物中的平均含量,施用污泥未对黑麦草造成重金属污染。 相似文献
997.
998.
The mechanism of addition reaction between carbene and epoxyethane has been investigated employing the MP2 and B3LYP/6-311+G*
levels of theory. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the
potential energy surface have been calculated. Based on the calculated results at the MP2/6-311+G* level of theory, it can
be predicted that there are two reaction mechanisms (1) and (2). In the first reaction carbene attacks the atom O of epoxyethane
to form an intermediate 1a (IM1a), which is a barrier-free exothermic reaction. Then, IM1a can isomerize to IM1b via a transition
state 1a (TS1a), where the potential barrier is 48.6 kJ/mol. Subsequently, IM1b isomerizes to a product epoxypropane (Pro1)
via TS1b with a potential barrier of 14.2 kJ/mol. In the second carbene attacks the atom C of epoxyethane firstly to form
IM2 via TS2a. Then IM2 isomerizes to a product allyl alcohol (Pro2) via TS2b with a potential barrier of 101.6 kJ/mol. Correspondingly,
the reaction energies for the reactions (1) and (2) are −448.4 and −501.6 kJ/mol, respectively. Additionally, the orbital interactions are also discussed for the leading intermediate.
The results based on the B3LYP/6-311+G* level of theory are paralleled to those on the MP2/6-311+G* level of theory. Furthermore,
the halogen and methyl substituent effects of H2C: on the two reaction mechanisms have been investigated. The calculated results indicate that the introductions of halogen
or methyl make the addition reaction difficult to proceed. 相似文献
999.
Let G be an extension of ℚ by a direct sum of r copies of ℚ. (1) If G is abelian, then G is a direct sum of r + 1 copies of ℚ and AutG ≅ GL(r + 1, Q); (2) If G is non-abelian, then G is a direct product of an extraspecial ℚ-group E and m copies of ℚ, where E/ζE is a linear space over Q with dimension 2n and m + 2n = r. Furthermore, let AutG′G be the normal subgroup of AutG consisting of all elements of AutG which act trivially on the derived subgroup G′ of G, and AutG/ζG,ζGG be the normal subgroup of AutG consisting of all central automorphisms of G which also act trivially on the center ζG of G. Then (i) The extension 1 → AutG′G → AutG → AutG′ → 1 is split; (ii) AutG′G/AutG/ζG,ζGG ≅ Sp(2n,Q) × (GL(m, Q) ⋉ ℚ(m)); (iii) AutG/ζG,ζGG/InnG ≅ ℚ(2nm). 相似文献
1000.
A simple and controllable electrodeposition approach was proposed for one‐step construction of glucose biosensors by in situ co‐deposition of ferrocene‐branched chitosan derivatives (CS‐Fc), multiwalled carbon nanotubes (MWNTs), and glucose oxidase (GOD) onto electrode surface. The formation of CS‐Fc could not only effectively prevent the leakage of Fc and retain its electrochemical activity, but also provide a biocompatible microenvironment for retaining the native activity of the immobilized biomolecules. Further entrapment of MWNTs into the CS matrix improved electronic conductivity of the biocomposite significantly. The facile procedure of immobilizing GOD and the promising feature of biocomposite will offer a versatile platform to fabricate biosensors and bioelectronic devices. 相似文献