Research on Chemical Intermediates - A recent “Renaissance” has various fields of chemistry exploring processes that are more Earth-friendly One focus is to make kinetic experiments... 相似文献
Thermoelectric powers of a series of compounds RFeAsO (R = Ce, Pr, Nd, Sm and Gd) have been reported for temperatures ranging from 77 K up to room temperature. The behavior of S(T) in this temperature range can be divided into three regions. Every region has been fitted with mathematical functions of T. The physical significance of separate terms in the mathematical functions has been discussed. Some kind of universality has been observed between different members of the series. 相似文献
This paper presents an overview of our theoretical investigations in search of Efimov states in light 2-neutron halo nuclei.
The calculations have been carried out within a three-body formalism, assuming a compact core and two valence neutrons forming
the halo. The calculations provide strong evidence for the occurrence of at least two Efimov states in 20C nucleus. These excited states move into the continuum as the two-body (core-neutron) binding energy is increased and show
up as asymmetric resonances in the elastic scattering cross-section of the n-19C system. The Fano mechanism is invoked to explain the asymmetry. The calculations have been extended to 38Mg, 32Ne and a hypothetical case of a very heavy core (A = 100) with two valence neutrons. In all these cases the Efimov states show up as resonances as the two-body energy is increased.
However, in sharp contrast, the Efimov states, for a system of three equal masses, show up as virtual states beyond a certain
value of the two-body interaction. 相似文献
Research on Chemical Intermediates - Surfactant is a special kind of amphiphilic compound composed of water-loving and hating parts. The remarkable physical properties like interfacial tension,... 相似文献
Direct electrochemical studies on horse heart myoglobin and horseradish peroxidase (HRP) have been carried out using tin-doped indium oxide (ITO) and surfactant modified glassy carbon working electrodes. These proteins show very slow electron transfer kinetics at metal or untreated electrodes. Moreover, small amounts of surface-active impurity were drastically affects the electrode reaction of these proteins. The results showed that modification of the electrode surface with neutral surfactants significantly improves the electrochemical response of myoglobin as well as of HRP. The electrode response was found to depend on the structure of the surfactants. The amount of surfactant required per unit area of the electrode surface to promote the maximum electron transfer rate constants was found to be constant. This indicated that the surfactant molecules interacted with the electrode surface in a specific manner and anchored the protein molecules to align in the suitable orientation. The hydrophobicity of the surfactants rather than their charge was found to be crucial in promoting the electrode response of these proteins at the glassy carbon electrode. 相似文献
A catalytic route toward chiral Morita–Baylis–Hillman esters by asymmetric coupling between α,β‐acetylenic esters, aldehydes, and trimethylsilyl iodide has been developed (see scheme). The reaction proceeds with high to excellent enantioselectivities, and the products can be transformed into β‐branched derivatives in a single step and with excellent retention of configuration. TMS=trimethylsilyl