Starting from the shell model configurations,valence nucleon effctive interactions and fermion E2 transition operator,a microscopic approach of sdgIBM-2 is used to calculate the energy spectra,E2 transitions,and bindi...Starting from the shell model configurations,valence nucleon effctive interactions and fermion E2 transition operator,a microscopic approach of sdgIBM-2 is used to calculate the energy spectra,E2 transitions,and binding energies for 48,52,56Cr.The results fit the experimental data quite well.展开更多
We conducted a systematic study of oxide minerals in LL3.0-6 chondrites, and found ilmenite, rutile, perovskite and an unknown Al-Ti-Zr-oxide. Ilmenite is low in abundance, but is present in the chondrules and matrix ...We conducted a systematic study of oxide minerals in LL3.0-6 chondrites, and found ilmenite, rutile, perovskite and an unknown Al-Ti-Zr-oxide. Ilmenite is low in abundance, but is present in the chondrules and matrix of all the samples that we studied. The MnO content of ilmenite in LL3.0-3.3 is lower than that in LL3.5-6. The low concentration of MnO in the former is due to crystallization from chondrules melts at high temperatures. On the other hand, ilmenite composition in LL3.5-6 reflects thermal metamorphism. Therefore, ilmenite is indicative of petrologic type. We also made the first measurements of the 53Mn-53Cr systematics of ilmenite in ordinary chondrites. The age for ilmenite in Y790256 (LL6) is determined to be about 2 Ma older than angrites. This may represent the metamorphic age of the LL chondrites.展开更多
High Cr(VI) concentration is a potential serious risk to environment and ecologic system.Thus,it is essential to effectively monitor Cr contamination in water systems and scientifically evaluate its evolution trend.A ...High Cr(VI) concentration is a potential serious risk to environment and ecologic system.Thus,it is essential to effectively monitor Cr contamination in water systems and scientifically evaluate its evolution trend.A new method of in-situ tracer technique by Cr isotopic analysis for quantitatively estimating Cr-contamination and its regional evolution in natural waters as well as a case application are reported in this paper.Based on documented literatures,an experimental procedure for chemical separation and purification of Cr in water samples and its analytical method for Cr isotopic measurement by thermal ionization mass spectrometry(TIMS) are established.Eleven samples collected around a chemical factory in Hubei Province were analyzed by this technique.These samples showδ53Cr values ranging from-1.7‰to 7.3‰and an elevating trend with an increasing in distance from the sampling site to pollution source.A functional correlation following Rayleigh fractionation law was established between sample'sδ53Cr value and its extent of Cr contamination.This study suggests that Cr isotopic analysis is an effective method to reveal the spatial distribution and its evolution trend of Cr contamination in the regional water system.It is thus helpful to assessing the self-purifying ability of local water system according to Cr isotopic fractionation.展开更多
文摘Starting from the shell model configurations,valence nucleon effctive interactions and fermion E2 transition operator,a microscopic approach of sdgIBM-2 is used to calculate the energy spectra,E2 transitions,and binding energies for 48,52,56Cr.The results fit the experimental data quite well.
文摘We conducted a systematic study of oxide minerals in LL3.0-6 chondrites, and found ilmenite, rutile, perovskite and an unknown Al-Ti-Zr-oxide. Ilmenite is low in abundance, but is present in the chondrules and matrix of all the samples that we studied. The MnO content of ilmenite in LL3.0-3.3 is lower than that in LL3.5-6. The low concentration of MnO in the former is due to crystallization from chondrules melts at high temperatures. On the other hand, ilmenite composition in LL3.5-6 reflects thermal metamorphism. Therefore, ilmenite is indicative of petrologic type. We also made the first measurements of the 53Mn-53Cr systematics of ilmenite in ordinary chondrites. The age for ilmenite in Y790256 (LL6) is determined to be about 2 Ma older than angrites. This may represent the metamorphic age of the LL chondrites.
基金supported by the National Natural Science Foundation of China(Grant No. 40402021)
文摘High Cr(VI) concentration is a potential serious risk to environment and ecologic system.Thus,it is essential to effectively monitor Cr contamination in water systems and scientifically evaluate its evolution trend.A new method of in-situ tracer technique by Cr isotopic analysis for quantitatively estimating Cr-contamination and its regional evolution in natural waters as well as a case application are reported in this paper.Based on documented literatures,an experimental procedure for chemical separation and purification of Cr in water samples and its analytical method for Cr isotopic measurement by thermal ionization mass spectrometry(TIMS) are established.Eleven samples collected around a chemical factory in Hubei Province were analyzed by this technique.These samples showδ53Cr values ranging from-1.7‰to 7.3‰and an elevating trend with an increasing in distance from the sampling site to pollution source.A functional correlation following Rayleigh fractionation law was established between sample'sδ53Cr value and its extent of Cr contamination.This study suggests that Cr isotopic analysis is an effective method to reveal the spatial distribution and its evolution trend of Cr contamination in the regional water system.It is thus helpful to assessing the self-purifying ability of local water system according to Cr isotopic fractionation.
