Synthesis of New Types of N‐Arylpiperazine Phosphoramide Analogues of Chrysin

Several N‐arylpiperazine phosphoramide analogues of chrysin are synthesized through a facile phosphorylated reaction for the first time. Their structures are elucidated by NMR, ESI MS, IR and Element analysis. The results showed that the phosphorylation action occurred regioselectively only at the hydroxyl group of 7 position of chrysin.     

Derivative reproducing properties for kernel methods in learning theory

The regularity of functions from reproducing kernel Hilbert spaces (RKHSs) is studied in the setting of learning theory. We provide a reproducing property for partial derivatives up to order s when the Mercer kernel is C^2s. For such a kernel on a general domain we show that the RKHS can be embedded into the function space C^s. These observations yield a representer theorem for regularized learning algorithms involving data for function values and gradients. Examples of Hermite learning and semi-supervised learning penalized by gradients on data are considered.     

Steffensen type methods for solving nonlinear equations

In the present paper, by approximating the derivatives in the well known fourth-order Ostrowski’s method and in a sixth-order improved Ostrowski’s method by central-difference quotients, we obtain new modifications of these methods free from derivatives. We prove the important fact that the methods obtained preserve their convergence orders 4 and 6, respectively, without calculating any derivatives. Finally, numerical tests confirm the theoretical results and allow us to compare these variants with the corresponding methods that make use of derivatives and with the classical Newton’s method.     

Synthesis and physicochemical properties of the Al(III), Ga(III) and In(III) complexes with chrysin

New solid compounds of Al(III), Ga(III) and In(III) with chrysin were obtained. Their composition and some physicochemical properties were studied by thermogravimetric analysis, UV-vis, infrared and solid state ¹³C NMR spectroscopies. Upon heating the hydrated compounds M(C₁₅H₉O₄)₃·nH₂O decomposed to the oxides. The structure of the compounds was elucidated on the basis of obtained results.     

Determination of Amoxycillin and Clavulanic Acid in Some Pharmaceutical Preparations by Derivative Spectrophotometry

 Derivative spectrophotometry was applied for the simultaneous determination of amoxycillin and clavulanic acid in pharmaceutical preparations: “Augmentin” inj. and tablets and “Amoksiklav” drops and tablets, in solutions after hydrolysis with sodium hydroxide. As the absorption spectra overlap strongly (amoxycillin λ_max = 247 nm and 290 nm, clavulanic acid λ_max = 258 nm) the first and the second derivative spectrophotometric procedure was elaborated for their determination. Amoxycillin was determined at λ = 257.9 nm (1-st derivative spectra) or λ = 273 nm (2-nd derivative) while clavulanic acid at λ = 280.3 nm (1-st derivative) or λ = 285 nm (2-nd derivative spectra). The Beer’s law is obeyed in the range of 0.004–0.04 mg/ml for amoxycillin and 0.002–0.02 mg/ml for clavulanic acid. Received December 6, 1999. Revision August 1, 2000.     

Simultaneous Determination of Anthocyanin and Ponceau 4R in Drink Powders by Derivative Spectrophotometry and Partial Least-Squares Multivariate Spectrophotometric Calibration

Summary.  Two methods for the simultaneous determination of anthocyanin and ponceau 4R in drink powders by second derivative spectrophotometry and by partial least-squares multivariate spectrophotometric calibration are described. The procedures do not require any separation step. The methods were applied to determine both colorants in commercial gelatin powders; the results obtained are compared. Received September 7, 2000. Accepted (revised) November 20, 2000     

The Range Set of Meromorphic Derivatives

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meso-四(对甲氧苯基)卟啉与锌(Ⅱ)、铜(Ⅱ)的显色反应及其导数行为研究

本文用自己合成的meso-四(对甲氧苯基)卟啉显色剂研究了Zn和Cu的高灵敏测试方法。在吐温-80存在下,PH7.05时,T(4-MOP)P(上述试剂)与Zn和Cu的显色反应于沸水浴中加热15和7min能定量进行,其摩尔吸光系数分别为4.95×10~5和3.39×10~5。用于纯铅样品中锌和铜的测定,结果与原子吸收法相吻合。本文还对Zn、Cu显色体系的导数光谱行为进行了探讨。其结果,它们的四阶导数摩尔系数响应值为8.85×10~6和5.50×10~6,不酸化时,Zn体系竟达1.12×10~7,灵敏度提高17～30倍。     

同步-导数荧光分析法多组份同时测定的可行性判断

本文对同步荧光光谱及其导数光谱进行计算机模拟,并由微机处理结果来判断多组份体系同步-导数荧光分析法同时测定的可行性。