PURIFICATION OF GINKGO LEAVES EXTRACT WITH MACROPOROUS ADSORBENT BASED ON UREA-FORMALDEHYDE CONDENSED POLYMERS

I INTRODUCTIONGinkgo biloba L. is one of the important economic trees, which is widely distributed inChina. In recent years, medicinal and healthful preparations based on the extractS from ginkgoleaves have been rapidly developed for the treatment of peripheral circulatory and cerebralinsufficiencyl']. Such eXtracts contain flavonol glycosides and terpene lactones as thepharmacologically active compounds. Organic-solvent extraction is one of the earliest methodsto prepare the extracts o…     

Precise absolute positioning for a single-frequency user

A new strategy to realize precise absolute positioning for a single-frequency user is presented. In the presented strategy, the receiver clock and ambiguities are removed using the satelliteand epoch-differenced (SDED) algorithm. As a further development of the SDED algorithm, a regional augmentation network is used to generate the SDED atmospheric delays at the user. The weakened mathematic property due to the epoch-differenced operation is improved by adding the generated atmospheric delays and applying the robust estimation. To test the new approach, the 24-h data at 5 Continuous Operation Reference Station (CORS) stations in Shanghai is processed. The results show a more than 96% success rate, defined as the case where three directions achieve the desired positioning accuracy of 10 cm, when the observation is longer than 20 min. The 20-min static results show that the new method can reach an accuracy of 3.42, 4.76 and 9.26 cm in the North, East and Up directions, respectively. An experiment was carried out to assess the kinematic positioning. The results show that the kinematic positioning accuracy is 4.11, 5.31 and 4.05 cm in the north-south, east-west and height directions,respectively.     

Additional symmetries of constrained CKP and BKP hierarchies

The additional symmetries of the constrained CKP (cCKP) and BKP (cBKP) hierarchies are given by their actions on the Lax operators, and their actions on the eigenfunction and adjoint eigenfunction {Φ i , Ψ i } are presented explicitly. Furthermore, we show that acting on the space of the wave operator, *k forms new centerless W cC 1+∞ and W cB 1+∞ -subalgebra of centerless W 1+∞ respectively. In order to define above symmetry flows *k of the cCKP and cBKP hierarchies, two vital operators Y k are introduce...     

尼卡巴嗪原料药及制剂中4,4′-二硝基均苯二脲与2-羟基-4,6-二甲基嘧啶的HPLC法同时测定

建立了同时测定尼卡巴嗪原料药及其制剂中4,4′-二硝基均苯二脲(DNC)和2-羟基-4,6-二甲基嘧啶(HDP)的高效液相色谱法。试样用二甲基亚砜溶解,以Hypersil BDS C18为色谱柱,乙酸/乙酸铵溶液-乙腈(体积比1∶1)为流动相,HDP和DNC的检测波长分别为290、350 nm。DNC和HDP的质量浓度分别在0.354~70.9 mg/L和0.146~29.2 mg/L范围内与色谱峰面积呈良好线性关系,标准曲线方程分别为ρ=7.307×10-5S-0.043 58和ρ=1.648×10-5S-0.084 83,相关系数(r)分别为1.000和0.999 9。用建立的方法测定尼卡巴嗪原料药中的DNC和HDP含量,测定结果与分光光度法无显著差异,DNC和HDP的相对标准偏差均小于0.5%。     

余代数上余倾斜余模的结构

研究了余代数上余倾斜余模的结构特征,证明了每个余倾斜余模都可以写成不可分解的两两非同构的余模的直和形式,每个余倾斜余模包含所有的内射不可分解模作为直和项.最后构造了余倾斜余模的两个例子.     

高校教育成本测算及其优化管理模型

在高校成本层次分类的基础上,建立了生均成本测算的一般模型,针对教育成本投入过程中因学生人数随机变化而存在的风险,引进教学质量函数,提出了办学效益和教学质量的双目标优化模型.利用凸分析和优化原理得到优化问题解的存在性,全部正解的β取值范围以及最优解满足的充要条件,对最优解的定量计算给出了基于Monte Carlo模拟的遗传算法设计,并进行了相应的经济意义分析.     

单相超导体CaLaBaCu_(3-x)BxO_(7-δ)正常态热电势率研究

从 77K到 30 0 K之间对 Ca L a Ba Cu3 -x Bx O7-δ单相体系的正常态热电势率进行了微分法测量 ,发现随着硼含量 x从 0向 0 .4的逐步增加 ,样品体系正常态特性从金属性向类半导体性质转变 ,其主要载流子由空穴型为主转变为电子型为主 .根据以上的性质转变 ,我们采用双带模型及半导体模型对 x的不同值进行曲线模拟 ,拟合的热电势率—温度曲线与实验曲线相当吻合 ,同时根据模型对样品的费米能及有效能隙进行了计算     

一维p-Laplacian方程边值问题多解的存在性

利用Clark定理，研究了一维p-Laplacian方程边值问题多解的存在性，得到了这类边值问题至少有n对非平凡解的充分条件．