Kantorovich-type inequalities and the measures of inefficiency of the glse

In this paper we introduce some Kantorovich inequalities for the Euclidean norm of a matrix, that is, the upper bounds to (X'B ^–1 X) ^–1 X'B ^–1 AB ^–1 X(X'B ^–1X)^–1 X' BX(X'AX) ^–1 X'CX² are given, where A²=trace (A'A). In terms of these inequalities the upper bounds to the three measures of inefficiency of the generalized least squares estimator (GLSE) in general Gauss-Markov models are also established.Project supported partially by the Third World Academy of Sciences under contract TWASRG 87-46 and by the National Natural Science Foundation.     

Linear mode conversion of waves near the maxima or minima of the density in a warm magnetized plasma

Behaviour of the h. f. electrostatic waves near the plasma or upper hybrid resonances was studied in the case that these resonances are situated at the maxima or minima of the plasma density. Supposing the parabolic density profile in these regions we obtained the connection formulae for the WKB solutions. In a weakly inhomogeneous magnetoplasma the effect of the parabolic profile manifests itself only in narrow frequency band centred at the resonance frequency corresponding to the extreme value of the density. The whole process can be then described by only two coefficients, viz. the power conversion and power transmission coefficients.     

Improved method for analyzing estrogens in water by liquid chromatography-electrospray mass spectrometry

An improved LC-electrospray ionization MS method was established for four estrogens (17beta-estradiol (E2), estriol (E3), estrone (E1), and ethynyl estradiol (EE)) in environmental water. Almost complete separation of all estrogens was achieved on a phenyl column with methanol/water as the mobile phase. Quantification was achieved in the negative ionization mode using selected ion monitoring. The instrumental detection limits were 20-30 ng/l for the four analytes. In Milli-Q spiked water, the recoveries of the four estrogens were 72-81%, which was similar to those found for river water spiked with the corresponding deuterated estrogens. The detection limits for the four estrogens in river water were 0.1-0.2 ng/l. The method was used to detect residual estrogens in the Tonghui River, which receives water from a municipal sewage treatment plant in Beijing; E1 (1.1 ng/l) and E2 (0.2 ng/l) were detected.     

电位滴定法测定模拟高放废液中的游离酸

本文研究了用电位滴定法测定模拟高放废液中游离酸的方法。用草酸钾做络合剂以消除Ｆｅ＾３＋、Ａｌ＾３＋、Ｎｄ＾３＋等多种水解离子的影响，用标准碱直接进行电位滴定，即可快速准确地测定模拟高放废液中游离酸的含量。方法的相对标准偏差为１．８％，标准加入回收率为１００－１０１％，能为放射性废物固化试验提供可靠的分析数据。     

食管贲门癌患者血清微量元素的变化

检测了３０例食管贲门癌患者手术羊后的ＳＣｕ，ＳＺｎ及Ｃｕ／Ｚｎ比值，并以２８例健康查体者作对照研究，发现：（１）食管贲门癌患者术前血清ＳＣｕ及Ｃｕ／Ｚｎ值高于对照，ＳＺｎ低于对照；（２）肿瘤患者术后１０天血清ＳＣｕ及Ｃｕ／Ｚｎ值下降，ＳＺｎ接近正常，通过本文研究提示，血清ＳＣｕ，ＳＺｎ及Ｃｕ／Ｚｎ比值与食管贲门癌患者的病情和疗效有关，可作为监测和判断病情和预后的辅助检查。     

膨润土对结晶紫的吸附

用分光光度、显微电泳和ｘ－射线衍射等方法研究了膨润土对结晶紫的吸附；实验表明，钙型膨润土在吸收结晶紫溶液时，加入钠盐可明显改善吸附效果。