反相高效液相色谱法同时测定3—羟基苯甲酸及3,5—二羟基苯甲酸的含量

１引言３，５．二羟基苯甲酸（１）及３－羟基苯甲酸（２）是合成咳喘素类药物的重要原料，它们本身的合成都是采用苯甲酸为原料，经磺化、碱熔得到。为了提高（１）、（２）的纯度，通常需严格控制合成工艺条件。但难免（１）中伴随着（２），（２）中伴随着（１）。对于含量的测定，通常是采用酸碱滴定法，但此时测得的是（１）、（２）的总量，无法确定它们各自的纯度。为此，我们研究了（１）、（２）在ＲＰ－ＨＰＭ上分离检测的最佳适宜条件，经１０余种流动相及不同流量的试验，结果表明：用乙睛－缓冲溶液（每升含７ｇ磷酸二氢钾，０…     

扩展的谐振子Feynman公式及其应用

本文给出谐振子包含极点和超越极点的扩展Feynman传播子公式的新推导。我们应用了传播子的本征函数展开,从而揭示出Maslov修正和本征函数字称的关系。这一扩展的 Feynman公式被用来讨论在稳恒均匀磁场中和有Chern-Simon背景规范场存在时迴旋运动带电粒子Feynman传播子位相修正及其物理效应。     

激光偏振取向与光栅能量吸收及破坏阈值的关系

本文从实验和理论方面研究了光栅吸收与入射激光的偏振取向和波长的关系.从计算模型得出的理论结果与观察值相符.     

原子-原子相互作用影响下Dicke模型的量子相变

原子与光腔相互作用的动力学特性的研究一直是量子光学研究的热点,本文利用自旋相干态变换和基态变分法从理论上求解光腔中冷原子系统的基态能量表达式,并且给出丰富的基态相图。在正常相时给出基态能量稳定值的解析解;而超辐射相时,我们可以利用迭代的方法近似得到原子布居数、平均光子数和基态能量随原子-场耦合强度的变化。本文主要呈现出原子-原子相互作用强度改变正常相到超辐射相的量子相变点,且是一阶相变,但未出现新的量子相和量子相变。     

Atomistic simulation of fcc-bcc phase transition in single crystal Al under uniform compression

By molecular dynamics simulations employing an embedded atom model potential,we investigate the fcc-to-bcc phase transition in single crystal Al,caused by uniform compression.Results show that the fcc structure is unstable when the pressure is over 250 GPa,in reasonable agreement with the calculated value through the density functional theory.The morphology evolution of the structural transition and the corresponding transition mechanism are analysed in detail.The bcc (011) planes are transited from the fcc (11) plane and the (11) plane.We suggest that the transition mechanism consists mainly of compression,shear,slid and rotation of the lattice.In addition,our radial distribution function analysis explicitly indicates the phase transition of Al from fcc phase to bcc structure.     

Interaction-Induced Chiral Quantum States of the Ultracold Polar Molecules

The ultracold polar molecules with the tunable dipole-dipole interaction, not only would enable explorations of a large class of exotic many-body physics phenomena, but also could be used for quantum information processing. In the present paper we demonstrate that this dipole-dipole interaction can generate the degenerate chiral quantum states acting as a qubit robust against noise when the ultracold polar molecules are confined by a triangular lattice. Moreover, we also find two first-order quantum phase transitions by controlling an external driving field. One is the transition with the change of the different degenerate chiral quantum states. The other is the transition with the breaking of the degenerate quantum chiral states to the nondegenerate state. In experiment, these first-order quantum phase transitions can be detected by measuring the collective molecular population.