For magmatic rocks,it is often found that zircon 206 Pb/238 U and 207 Pb/235 U ratios continuously plot on the concordia line with a relatively large age span for the same sample,which gives rise to large dating error...For magmatic rocks,it is often found that zircon 206 Pb/238 U and 207 Pb/235 U ratios continuously plot on the concordia line with a relatively large age span for the same sample,which gives rise to large dating errors or even unrealistic dating results.As the trace element concentrations of zircon can reflect its equilibrated magma characteristics,they can be used to determine whether all the analytical spots on the zircons selected to calculate the weighted mean age are cogenetic and formed in a single magma chamber.This work utilizes the results of zircon trace element concentrations and U-Pb isotopic analyses to explore the screening of reasonable U-Pb ages,which can be used to determine a more accurate intrusion crystallization age.The late Mesozoic Huayuangong granitic pluton complex,which is located in the Lower Yangtze region,eastern China,was selected for a case study.The Huayuangong pluton comprises the central intrusion and the marginal intrusion.Two samples from the marginal intrusion yielded consistent zircon weighted mean 206 Pb/238 U ages of 124.6±2.0 Ma and 125.9±1.6 Ma.These analytical spots also exhibit Zr/Hf and Th/U ratios concordant with the evolution of a single magma,from which the dated zircons crystallized.However,for the central intrusion,the analytical spots on zircons from two samples all show a continuous distribution on the concordia line with a relatively large age span.For each sample from the central intrusion,the zircon Zr/Hf ratios do not conform to a single magma evolutionary trend,but rather can be divided into two groups.We propose that zircon Zr/Hf ratios can provide a new constraint on U-Pb zircon dating and zircon Th/U ratios can also be used as a supplementary indicator to constrain zircon dating and determine the origins of the zircons and whether magma mixing has occurred.By screening zircon analytical spots using these two indicators,the two samples from the central intrusion of the Huayuangong pluton produce results of 122.8±4.3 Ma and 122.9±2.2 Ma,which are consistent with the field observations that the central intrusion is slightly younger than the marginal intrusion.展开更多
Although zircon U-Pb geochronometer has been widely used for dating metamorphism in moderate- to high-grade metamorphic rocks, it is still difficult to link the zircon U-Pb age to pressure and temperature （P-T） cond...Although zircon U-Pb geochronometer has been widely used for dating metamorphism in moderate- to high-grade metamorphic rocks, it is still difficult to link the zircon U-Pb age to pressure and temperature （P-T） conditions. In this study, zircon trace elements and Hf isotopes and REE partitioning between zircon and garnet are adopted to track the formation condition of zircon in the granu- lites from North Tongbai Orogen, Central China. Combined with previous metamorphic P-T path results, a quantitative integrated anticlockwise P-T-t path was established for Tongbai granulites. These grauulites recorded an early low-P heating followed by a dramatic pressure increase. Evidence for the prograde history （M1） is provided by cordierite, orthopyroxene and biotite inclusions in garnet. The prograde metamorphism occurred at around 443±3 Ma, with P-T conditions of ca. 730-820 ℃ and 〈6 kbar. The peak metamorphic （M2） condition is 〉920 ℃ and 8.5-10 kbar and the peak metamorphism age is ca. 432±4 Ma. At around 419 Ma, the granulites suffered an amphibolite-facies retrograde metamorphism （M3）, represented by the replacement of garnet by biotite and plagioclase, and clinopyroxene by amphibole, with metamorphic condition of ca. 700℃ and ca. 7 kbar. The last retrograde metamorphism （M4） is a greenschist-facies overprint with an age of ca. 404 Ma. It is concluded that the meta- morphism of Tongbai granulite lasted for more than 40 Ma, including a stage of more than 20 Ma granulitc-facies metamorphism. The prolonged granulite-facies metamorphism resulted from the continuous northward subduction of the Shangdan oceanic crust beneath the North Qinling terrane.展开更多
目的探讨综合护理干预对内生场深部热疗配合胸腹腔灌注化疗治疗恶性胸腹水患者生活质量的影响。方法选取2015年11月-2016年5月接受治疗的恶性胸腹水患者92例,采用随机数字表法将其分为对照组和研究组各46例。对照组给予常规护理,研究组...目的探讨综合护理干预对内生场深部热疗配合胸腹腔灌注化疗治疗恶性胸腹水患者生活质量的影响。方法选取2015年11月-2016年5月接受治疗的恶性胸腹水患者92例,采用随机数字表法将其分为对照组和研究组各46例。对照组给予常规护理,研究组在对照组基础上给予综合护理干预。采用焦虑自评量表(self-rating anxiety scale,SAS)和生活质量量表(quality of life questionnaire-core 30,QLQ-C30)评估2组患者的焦虑状态和生活质量。并比较2组患者对护理工作的满意度。结果干预后研究组的SAS评分和QLQ-C30各项评分均低于对照组,护理满意率高于对照组(χ2=5.373,P=0.021)。结论综合护理干预可有效减轻内生场深部热疗配合胸腹腔灌注化疗治疗的恶性胸腹水患者的焦虑情绪,改善患者的生活质量,并可提高患者对护理工作的满意度。展开更多
特征提取和健康状态的辨识是复杂系统健康状态评估中的关键问题。提出一种新的健康状态评估方法,该方法分为3个步骤:首先,采用经验模态分解(empirical model decomposition,EMD)和奇异值分解(singular value decomposition,SVD)来提取...特征提取和健康状态的辨识是复杂系统健康状态评估中的关键问题。提出一种新的健康状态评估方法,该方法分为3个步骤:首先,采用经验模态分解(empirical model decomposition,EMD)和奇异值分解(singular value decomposition,SVD)来提取振动信号的特征变量。然后,运用马田系统(Mahalanobis-Taguchi system,MTS)构造马氏空间,并对其进行优化,从而降低特征变量的维度。最后,提出了一种健康度(health index,HI)的概念,并且用来对复杂系统健康问题进行评估。该方法成功地应用在轴承的健康状态评估中。展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.41672052)the National Key R&D Program of China(Grant No.2016YFC0600203)。
文摘For magmatic rocks,it is often found that zircon 206 Pb/238 U and 207 Pb/235 U ratios continuously plot on the concordia line with a relatively large age span for the same sample,which gives rise to large dating errors or even unrealistic dating results.As the trace element concentrations of zircon can reflect its equilibrated magma characteristics,they can be used to determine whether all the analytical spots on the zircons selected to calculate the weighted mean age are cogenetic and formed in a single magma chamber.This work utilizes the results of zircon trace element concentrations and U-Pb isotopic analyses to explore the screening of reasonable U-Pb ages,which can be used to determine a more accurate intrusion crystallization age.The late Mesozoic Huayuangong granitic pluton complex,which is located in the Lower Yangtze region,eastern China,was selected for a case study.The Huayuangong pluton comprises the central intrusion and the marginal intrusion.Two samples from the marginal intrusion yielded consistent zircon weighted mean 206 Pb/238 U ages of 124.6±2.0 Ma and 125.9±1.6 Ma.These analytical spots also exhibit Zr/Hf and Th/U ratios concordant with the evolution of a single magma,from which the dated zircons crystallized.However,for the central intrusion,the analytical spots on zircons from two samples all show a continuous distribution on the concordia line with a relatively large age span.For each sample from the central intrusion,the zircon Zr/Hf ratios do not conform to a single magma evolutionary trend,but rather can be divided into two groups.We propose that zircon Zr/Hf ratios can provide a new constraint on U-Pb zircon dating and zircon Th/U ratios can also be used as a supplementary indicator to constrain zircon dating and determine the origins of the zircons and whether magma mixing has occurred.By screening zircon analytical spots using these two indicators,the two samples from the central intrusion of the Huayuangong pluton produce results of 122.8±4.3 Ma and 122.9±2.2 Ma,which are consistent with the field observations that the central intrusion is slightly younger than the marginal intrusion.
基金supported by the National Natural Science Foundation of China (No. 41302040)the China Geological Survey (No. DD20160201)
文摘Although zircon U-Pb geochronometer has been widely used for dating metamorphism in moderate- to high-grade metamorphic rocks, it is still difficult to link the zircon U-Pb age to pressure and temperature （P-T） conditions. In this study, zircon trace elements and Hf isotopes and REE partitioning between zircon and garnet are adopted to track the formation condition of zircon in the granu- lites from North Tongbai Orogen, Central China. Combined with previous metamorphic P-T path results, a quantitative integrated anticlockwise P-T-t path was established for Tongbai granulites. These grauulites recorded an early low-P heating followed by a dramatic pressure increase. Evidence for the prograde history （M1） is provided by cordierite, orthopyroxene and biotite inclusions in garnet. The prograde metamorphism occurred at around 443±3 Ma, with P-T conditions of ca. 730-820 ℃ and 〈6 kbar. The peak metamorphic （M2） condition is 〉920 ℃ and 8.5-10 kbar and the peak metamorphism age is ca. 432±4 Ma. At around 419 Ma, the granulites suffered an amphibolite-facies retrograde metamorphism （M3）, represented by the replacement of garnet by biotite and plagioclase, and clinopyroxene by amphibole, with metamorphic condition of ca. 700℃ and ca. 7 kbar. The last retrograde metamorphism （M4） is a greenschist-facies overprint with an age of ca. 404 Ma. It is concluded that the meta- morphism of Tongbai granulite lasted for more than 40 Ma, including a stage of more than 20 Ma granulitc-facies metamorphism. The prolonged granulite-facies metamorphism resulted from the continuous northward subduction of the Shangdan oceanic crust beneath the North Qinling terrane.
文摘目的探讨综合护理干预对内生场深部热疗配合胸腹腔灌注化疗治疗恶性胸腹水患者生活质量的影响。方法选取2015年11月-2016年5月接受治疗的恶性胸腹水患者92例,采用随机数字表法将其分为对照组和研究组各46例。对照组给予常规护理,研究组在对照组基础上给予综合护理干预。采用焦虑自评量表(self-rating anxiety scale,SAS)和生活质量量表(quality of life questionnaire-core 30,QLQ-C30)评估2组患者的焦虑状态和生活质量。并比较2组患者对护理工作的满意度。结果干预后研究组的SAS评分和QLQ-C30各项评分均低于对照组,护理满意率高于对照组(χ2=5.373,P=0.021)。结论综合护理干预可有效减轻内生场深部热疗配合胸腹腔灌注化疗治疗的恶性胸腹水患者的焦虑情绪,改善患者的生活质量,并可提高患者对护理工作的满意度。
文摘特征提取和健康状态的辨识是复杂系统健康状态评估中的关键问题。提出一种新的健康状态评估方法,该方法分为3个步骤:首先,采用经验模态分解(empirical model decomposition,EMD)和奇异值分解(singular value decomposition,SVD)来提取振动信号的特征变量。然后,运用马田系统(Mahalanobis-Taguchi system,MTS)构造马氏空间,并对其进行优化,从而降低特征变量的维度。最后,提出了一种健康度(health index,HI)的概念,并且用来对复杂系统健康问题进行评估。该方法成功地应用在轴承的健康状态评估中。
