两性药物土霉素的传感电极及其选择性规律

用离子选择性电极测定药物,研究甚多,其中大都是生物碱、季铵等类碱性药物,与非水滴定等法相比、优点并不显著,至于抗生素类药物,常用微生物法分析,缺点很多,本文报告土霉素的阳离子型与阴离子型电极,探讨了选择性规律,电极在pH1.6～3.2与pH8.0～11.0分别响应含质子化二甲胺基的土霉素一价阳离子与含离解B环烯醇基的土霉素一价阴离子,1gK_ij与季铵离子势及诱导效应指数有良好的线性关系,符合1gK_ij=a+bI-cZ/R,极限值7.07。     

不同分支坑道分布形式及分布位置对油气爆炸超压特性的影响

为探索洞库支坑道不同分布形式及分布位置对坑道内油气爆炸超压特性的影响,在控制容积、初始油气浓度以及点火能不变的情况下,开展了不同支坑道分布形式及分布位置条件下油气的爆炸超压特性实验,重点对最大超压、最大超压时间、超压上升速率、爆炸强度指数等主要超压特性参数进行了分析。结果表明：密闭容器内坑道的分布形式及分布位置对容器内油气爆炸超压特性有显著影响。相对布置形式下最大超压、最大超压上升速率、爆炸强度指数均小于一字排开和交错布置,达到最大超压和最大超压上升速率的时间也有所延后。3种不同分支坑道分布位置下,最大爆炸超压上升速率和爆炸强度指数由大到小依次为：远离点火端、靠近点火端、沿主坑道均匀分布。分支坑道距离点火端越远,爆炸强度指数越大, 分支坑道距离点火端越近,达到最大爆炸超压上升速率的时间越提前。

     

一道三重积分计算题引出的思考

通过对一道三重积分计算题的引申和探索,启发学生思考,掌握三重积分的计算.     

可见光域叠层成像中照明光束的关键参量研究

研究了可见光域叠层成像中照明光束的系列关键参量对成像质量的影响. 利用叠层成像迭代恢复算法,通过模拟实验研究了照明光束的交叠率、光束尺寸以及几何形状对成像恢复质量的相互制约关系. 模拟结果表明,光束的交叠率是影响成像恢复质量的主要因素,光束的形状主要影响成像的收敛速度,而光束尺寸对成像的恢复质量以及收敛速度直接影响较小. 因此,通过模拟可以对可见光域、X 射线以及电子波段等其他波段的实验进行系统优化照明光束参数起到一定的理论指导作用. 关键词： 相干衍射 叠层成像 相位恢复     

关于幂级数求和的教学实例分析

通过几组教学实例,阐述如何通过积分、求导、拆项等方法将复杂的幂级数转化为简单的基本型幂级数和等比级数以求其和函数.     

d-维r阶二进求导极大算子的有界性(英文)

本文研究了p-级数域的特征系统的r阶二进求导极大算子的有界性.利用狄利克雷核的重要性质,构造了反例证明此极大算子在d维情况下不是从Hardy空间Hq到Hardy空间Hq有界的,其中0相似文献   

奎宁药物在油/水界面上的迁移机理研究

本文用电流扫描极谱法研究了奎宁药物在水/1,2-二氯乙烷界面上的迁移现象。探讨了水相pH,奎宁浓度及滴水速度与波高的关系。研究了不同基础电解质、缓冲溶液和有机溶剂对极谱波的影响。比较了奎宁存在于水相和有机相时的迁移特性。发现单、双质子化奎宁离子均能迁移跨过界面,产生两个极谱波。结果表明:奎宁在界面上的迁移过程同时受扩散和质子化平衡受损后再化合反应速度控制,并用计时电位法做了进一步的研究。在理论分析的基础上,推导出极谱波极限电流的表达式。理论与实验相符。提出了奎宁在油/水界面上的迁移机理。     

TRANSFER MECHANISM OF QUININE DRUG ACROSS THE OIL/WATER (O/W) INTERFACE

The transfer phenomena of quinine drug at the aqueous 1,2- dichloroethane (DCE)interface have been studied by the current- scanning polarography. The relationships be-tween the wave height and pH of aqueous phase, concentration of quinine as well as therate of water drop are discussed. The effect of supporting electrolyte, buffer solution andthe nature of organic solvent on the polarographic wave is studied. The transfer char-acteristics of quinine in aqueous phase and in organic phase are compared, The mono- pro-tonated and diprotonated quinines can both transfer at the interface so as to produce twopolarographic waves. The transfer process of quinine at the interface is simultaneouslycontrolled by diffusion and reestablishment of the disturbed protonated equilibrium ofquinine. A further investigation is made by chronopotentiometry. On the basis of thetheoretical analysis, the formulae of the limiting current are derived and discussed. Thetheoretical results are in agreement with the experimental ones.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ION-SELECTIVE ELECTRODES (Ⅱ)——SULPHA-DRUG SENSITIVE ELECTRODES USING QUATERNARY PHOSPHONIUM AND ARSONIUM COMPOUNDS

Ion-pair complexes of sulphonamide derivatives with quaternary phosphonium and quaternary arsonium have been synthesized and their electrode performances studied. It has been found that the electrode functions depend mainly on the site cation rather than on the anionic species and deteriorate in the order of cetyhrioctylammonium>cetyltriphenylphosphonium> cetyhriphenylarsonium. The electrode selectivity for different sulpha-drugs decreases in the order of sulphathiazole>sulphamethoxazole>sulphadimethoxine, sulphadoxine>sulphacetamide>sulphadiazine>sulphanilamide. Selectivity coefficients depend not only on the molecular connectivity index χ, but also on the electronic charge at the ionizing amide nitrogen atom σ and pK, according to the following formula: logK_(ij)=aχ+bσ—CpK_a—d. The quaternary phosphonium type electrodes have been suggested for use in the potentiometric determinations of sulpha-drugs.     

STUDIES ON RESPONSE CHARACTERISTICS OF DRUG ISE''''S (Ⅲ)——ERYTHROMYCIN ELECTRODES AND THEIR SELECTIVITY TOWARD QUATERNARY AMMONIUMS

Erythromycin sensitive electrodes have been proposed. Their selectivity toward quaternary ammoniums is described in terms of induction effect and steric hindrance effect: logKil=a_1I-a_2Z/R+a_0, where I is induction effect index, a_1,a_2 and a_0 are coefficients which depend on the electro-active material. A general formula has been suggested to relate the electrode selectivity to the carbon atom number (n) of the alkyl of the quaternary ammonium; logK_(ij)=A/2.7~R-B/(0.80+1.26n)+C, where A, B and C are coefficients which depend on the electro-actlve material, logK_(ij) tends to a limited value C when n increases.