Blood lead levels of 180 pupils from two elementary schools were determined and the intellec- tual development of the children was followed.The children in these two groups were similar in most nonlead variables.Resul...Blood lead levels of 180 pupils from two elementary schools were determined and the intellec- tual development of the children was followed.The children in these two groups were similar in most nonlead variables.Results showed that pupils at the school near a battery plant had higher blood lead levels than those at a school in a residential neighborhood.An evident dose- effect relationship between blood lead level and children's performance on psychological testing existed:the higher the blood level,the lower the intelligence quotient.This relationship re- mained after confounding factors were controlled by stepwise regression analysis.Partial regres- sion coefficients for PbB and verbal IQ,performance IQ,and full-scale IQ were -0.85,-0.71, and -0.91,respectively.1989 Academic Press,Inc.展开更多
Pb isotope ratios and their variation have been measured and explained on ores of massive S-Fe-Au depos-its hosted in the Middle-Upper Carboniferous, on feldspars from diorite bodies closely related tomineralization a...Pb isotope ratios and their variation have been measured and explained on ores of massive S-Fe-Au depos-its hosted in the Middle-Upper Carboniferous, on feldspars from diorite bodies closely related tomineralization and on whole rocks from ore-hosting strata (carbonate rocks) in the Tongling area, Anhui Prov-ince. Through a comparison of Pb isotope features of these geological bodies, it has been suggested that oresubstances of the deposits were derived from ore-hosting strata. In the meanwhile, the measurement of ore Pbisotopes of different mineralization types of the same deposit indicates that different mineralization types havedistinct Pb isotope characteristics, showing the potentiality of the Pb isotopic method used in mineral explora-tion.展开更多
The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA d...The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA data. The reaction products exhibit 12 compounds namely, Ba(NO3)2, αFe2O3, Fe3O4, BaFeO3, BaFeO2.9, hexagonal BaFeO3-x, tetragonal BaFeO3-x, BaFe2O4, αBaFe2O4, Ba2Fe6O11, Ba5Fe14O26 and BaFe12O19. The formation of these products depend on the molar ratio between the reactants and the reaction temperature. The reaction products were studied by DTA and TG techniques and characterized by X-ray diffraction patterns, magnetic susceptibility data and scanning electron microscopy, SEM.展开更多
The differential potentiometric stripping analysis (DPSA) with Nafion coated carbon fibre electrode has been studied, and a method to determine lead and cadmium in urine directly has been attempted. The effect of vari...The differential potentiometric stripping analysis (DPSA) with Nafion coated carbon fibre electrode has been studied, and a method to determine lead and cadmium in urine directly has been attempted. The effect of various experimental parameters on the DPSA response is discussed. The experimental conditions include 0.2M sodium perchlorate, deposition potential of-1.0 or -1.1 V and using 20 ppm mercuric ion as oxidizing agent. The response of the signal is in linear relation with the concentrations of lead and cadmium respectively up to 0.5 ppm. The electrode coated with Nafion film alleviates the interference from organics in urine samples.展开更多
文摘Blood lead levels of 180 pupils from two elementary schools were determined and the intellec- tual development of the children was followed.The children in these two groups were similar in most nonlead variables.Results showed that pupils at the school near a battery plant had higher blood lead levels than those at a school in a residential neighborhood.An evident dose- effect relationship between blood lead level and children's performance on psychological testing existed:the higher the blood level,the lower the intelligence quotient.This relationship re- mained after confounding factors were controlled by stepwise regression analysis.Partial regres- sion coefficients for PbB and verbal IQ,performance IQ,and full-scale IQ were -0.85,-0.71, and -0.91,respectively.1989 Academic Press,Inc.
文摘Pb isotope ratios and their variation have been measured and explained on ores of massive S-Fe-Au depos-its hosted in the Middle-Upper Carboniferous, on feldspars from diorite bodies closely related tomineralization and on whole rocks from ore-hosting strata (carbonate rocks) in the Tongling area, Anhui Prov-ince. Through a comparison of Pb isotope features of these geological bodies, it has been suggested that oresubstances of the deposits were derived from ore-hosting strata. In the meanwhile, the measurement of ore Pbisotopes of different mineralization types of the same deposit indicates that different mineralization types havedistinct Pb isotope characteristics, showing the potentiality of the Pb isotopic method used in mineral explora-tion.
文摘The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA data. The reaction products exhibit 12 compounds namely, Ba(NO3)2, αFe2O3, Fe3O4, BaFeO3, BaFeO2.9, hexagonal BaFeO3-x, tetragonal BaFeO3-x, BaFe2O4, αBaFe2O4, Ba2Fe6O11, Ba5Fe14O26 and BaFe12O19. The formation of these products depend on the molar ratio between the reactants and the reaction temperature. The reaction products were studied by DTA and TG techniques and characterized by X-ray diffraction patterns, magnetic susceptibility data and scanning electron microscopy, SEM.
基金This project was supported by the National Natural Science Foundation of China
文摘The differential potentiometric stripping analysis (DPSA) with Nafion coated carbon fibre electrode has been studied, and a method to determine lead and cadmium in urine directly has been attempted. The effect of various experimental parameters on the DPSA response is discussed. The experimental conditions include 0.2M sodium perchlorate, deposition potential of-1.0 or -1.1 V and using 20 ppm mercuric ion as oxidizing agent. The response of the signal is in linear relation with the concentrations of lead and cadmium respectively up to 0.5 ppm. The electrode coated with Nafion film alleviates the interference from organics in urine samples.
