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排序方式: 共有144条查询结果,搜索用时 46 毫秒
1.
贺诗华 《高等学校化学学报》2011,32(2):296-299
设计了简便构建屈螺酮分子中6β,7β-亚甲基结构的合成路线,并合成了屈螺酮.以16β,16β-亚甲基-3-氧代-17α-孕甾-4,6-二烯-21,17-羰内酯为起始原料,依次经硼氢化钠还原、间氯过氧苯甲酸环氧化、氢化铝锂还原性开环、Simmons-Smith加成以及铬酐氧化等5步反应得到目标化合物屈螺酮.中间体4β,5... 相似文献
2.
Mg2+, K+//Cl-, B4O2-7-H2O四元体系288 K固液相平衡 总被引:1,自引:1,他引:0
采用等温溶解平衡法研究了288 K时Mg2+, K+//Cl-, B4O2-7-H2O四元体系的相平衡关系, 测定该体系在288 K时平衡液相的溶解度和密度. 依据实验测定的平衡溶解度数据及对应的平衡固相, 绘制了该四元体系的平衡相图以及其密度-组成图. 研究结果表明, 四元体系Mg2+, K+//Cl-, B4O2-7-H2O 288 K时的固液相平衡实验中, 有复盐KCl·MgCl2·6H2O生成, 平衡相图中有3个共饱点, 7条单变量曲线, 5个结晶区, 对应的平衡固相分别为MgB4O7·9H2O, K2B4O7·4H2O, KCl, MgCl2·6H2O, KCl·MgCl2·6H2O. 简要讨论了实验结果. 相似文献
3.
Xue-Ping Zhang Wen-Yao Zhang Dan Wang Hai Zhang Shi-Hua Sang 《Russian Journal of Inorganic Chemistry》2017,62(7):995-1002
In this work, the solubilities of the salt minerals and the densities of solution in two ternary systems sodium chloride–zinc chloride–water and magnesium chloride–zinc chloride–water were measured at 373 K using an isothermal solution saturation method. Based on the determined equilibrium solubility data and the corresponding equilibrium solid phase, the phase diagrams and density diagrams of the two systems were plotted. The results show that the two ternary systems are complex and the eutectic points, the univariant solubility curves and the solid crystalline phase regions are shown and discussed. The phase diagram of the ternary system NaCl?ZnCl2?H2O at 373 K is constituted of two eutectic points, three univariant solubility curves and three solid crystalline phase regions corresponding to NaCl, ZnCl2 and 2NaCl · ZnCl2. And the phase diagram of the ternary system MgCl2?ZnCl2?H2O at 373 K includes two eutectic points, three univariant solubility curves and three solid crystalline phase regions corresponding to MgCl2 · 6H2O, MgCl2 · ZnCl2 · 5H2O and ZnCl2. The experimental results were simply discussed. 相似文献
4.
Phase equilibria of the quaternary NaCl–NaBr–Na2SO4–H2O system at 323 K were studied by the isothermal dissolution equilibrium method. The solubilities of salts and densities of saturated solutions were determined. Solid solutions [Na(Cl, Br)] were found in the experiments. The phase diagram of the quaternary system has no invariant point, but has one univariant curve at the boundary of Na(Cl, Br) and Na2SO4 crystallization fields. The experimental results show that an increase of the NaBr concentration is accompanied by an obvious increase of the solution density and the decrease of the solubilities of NaCl and Na2SO4. 相似文献
5.
Hamilton formalism and Noether symmetry for mechanico—electrical systems with fractional derivatives 下载免费PDF全文
This paper presents extensions to the traditional calculus of variations for mechanico-electrical systems containing fractional derivatives.The Euler-Lagrange equations and the Hamilton formalism of the mechanico-electrical systems with fractional derivatives are established.The definition and the criteria for the fractional generalized Noether quasisymmetry are presented.Furthermore,the fractional Noether theorem and conseved quantities of the systems are obtained by virtue of the invariance of the Hamiltonian action under the infinitesimal transformations.An example is presented to illustrate the application of the results. 相似文献
6.
CHEN Shi-Hua XIAO Jing-Lin 《理论物理通讯》2008,50(12):1287-1289
On the condition of electric-LO phonon strong coupling in unsymmetrical parabolic confinement potential quantum dot (QD), we obtain the eigenenergies of the ground state and the first-excited state, the eigenfunctions of the ground state, and the first-excited state by using variational method of Pekar type. This system in QD may be employed as a two-level quantum system-qubit. When the electron is in the superposition state of the ground state and the first-excited state, we obtain the time evolution of the electron density. The relations both the probability density of electron and the period of oscillation with the electron-LO-phonon coupling strength, the confinement strengths in the xy-plane and the z-direction are discussed. 相似文献
7.
利用荧光猝灭法,研究了不同温度、酸度下,Cu2+和 Fe3+与明胶的相互作用.计算了猝灭常数和结合常数.紫外光谱和显微红外光谱的测定结果表明,Cu2+、Fe3+与明胶分子中的酰胺键发生了作用.探讨了猝灭机理.计算出的热力学函数表明,在Cu2+、Fe3+与明胶的相互作用过程中熵变起主要的作用. 相似文献
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10.
钯催化下有机锡化合物的偶联反应在碳-碳键形成过程中的应用 总被引:2,自引:0,他引:2
本文述评了最近几年来钯催化的有机锡化合物与有机亲电试剂的交叉偶联反应在有机合成中用于碳-碳键形成的主要研究成果。主要讨论了直接交叉偶联反应,CO或烯键插入的交叉偶联反应和机理。 相似文献