The metamorphosed Early Paleoproterozoic granitoids in the Quanji massif, Northwest- ern China provide constraints for relationship between the Tarim Craton and North China Craton. Among granitoids batholiths, rocks o...The metamorphosed Early Paleoproterozoic granitoids in the Quanji massif, Northwest- ern China provide constraints for relationship between the Tarim Craton and North China Craton. Among granitoids batholiths, rocks of the Mohe quartz-diorite show typically adakitic geochemical characteristics, with medium K2O/Na2O ratios （0.56-1.17） and high Sr （519-619 ppm） low Y （9.37-20.40 ppm） and Yb （0.97-1.77 ppm） concentrations. The rocks have εNd（t） values between ＋2.4 and ＋4.4 and depleted mantle Nd model ages of 2.43-2.59 Ga. The magmatic zircons have positive εHf（t） values ranging from ＋0.40 to ＋7.60 and depleted mantle Hf model ages of 2.43-2.70 Ga, with major peaks at -2.54 and -2.65 Ga. The geochemical and Nd-Hf isotopic characteristics indicate that the Mohe quartz-dioritic rocks might be formed by partial melting of high-pressure metamorphosed juve- nile crustal rocks in post-orogenic extensional regime in the Early Paleoproterozoic. It suggests that important crustal growth occurred in the Quanji massif and the Tarim Craton at -2.4 and 2.5-2.7 Ga. The Quanji massif and Tarim Craton might share a similar crustal evolution history with the North China Craton in the Neoarchean.展开更多
Y型模块化多电平换流器(modular multilevel converter in Y configuration,Y-MMC)的Y形结构,使其预充电及并网过程更为复杂,基于环流控制的一般启动策略不再适用。针对上述问题,设计基于模型预测控制的渐进预充电方法及无扰动并网方法...Y型模块化多电平换流器(modular multilevel converter in Y configuration,Y-MMC)的Y形结构,使其预充电及并网过程更为复杂,基于环流控制的一般启动策略不再适用。针对上述问题,设计基于模型预测控制的渐进预充电方法及无扰动并网方法,提出一种模型预测渐进启动控制策略。首先,建立桥臂电流和电容电压预测模型,通过模型预测控制改变充电电流回路、幅值和相角,实现可控充电最大有功输入,对各个桥臂渐进充电。其次,根据电流误差灵活投切子模块,逐渐平衡充电回路电势差,辅助模型预测控制抑制冲击电流。然后,协调外环比例积分控制与内环模型预测控制,通过切换外环功率和电压控制模式,实现基于Y-MMC的柔性低频输电系统无扰动并网过程。最后,通过Matlab/Simulink对双端柔性低频输电系统进行仿真分析,所提控制策略保障了启动过程较低的电流冲击和较高的充电速度,使系统平稳快速进入稳定运行状态。展开更多
红石山地区印支期花岗岩位于甘肃北山地区的红石山蛇绿混杂岩带中,由马鞍山北岩体、小草湖岩体和红石山岩体组成,岩性主要为英云闪长岩、花岗闪长岩和二长花岗岩,含角闪质和镁铁质暗色深源包体。同位素年龄为237.8-240 M a,是中三叠世...红石山地区印支期花岗岩位于甘肃北山地区的红石山蛇绿混杂岩带中,由马鞍山北岩体、小草湖岩体和红石山岩体组成,岩性主要为英云闪长岩、花岗闪长岩和二长花岗岩,含角闪质和镁铁质暗色深源包体。同位素年龄为237.8-240 M a,是中三叠世侵位的。通过对其岩石化学、稀土和微量元素的研究表明,红石山地区印支期中酸性侵入岩大体可划分为两类：一类为高S r低Y型岩体（马鞍山岩体）,具有埃达克质岩的地球化学特征,推测可能是加厚的下地壳部分熔融形成的,其残留相为榴辉岩或角闪榴辉岩;另一类为低S r低Y型岩体（小草湖岩体和红石山岩体）,以较低的S r、A l和具明显的负铕异常而区别于埃达克质岩,又因其低Y和HREE而类似于埃达克质岩,推测源岩残留相中有斜长石存在,相当于高压麻粒岩相环境,可能也形成于加厚下地壳底部。展开更多
基金supported by the National Natural Science Foundation of China(Nos.40972042 and 41172069)Hong Kong RGC(No.HKU704312P)the Fundamental Research Funds for the Central Universities of of Ministry of Education,China
文摘The metamorphosed Early Paleoproterozoic granitoids in the Quanji massif, Northwest- ern China provide constraints for relationship between the Tarim Craton and North China Craton. Among granitoids batholiths, rocks of the Mohe quartz-diorite show typically adakitic geochemical characteristics, with medium K2O/Na2O ratios （0.56-1.17） and high Sr （519-619 ppm） low Y （9.37-20.40 ppm） and Yb （0.97-1.77 ppm） concentrations. The rocks have εNd（t） values between ＋2.4 and ＋4.4 and depleted mantle Nd model ages of 2.43-2.59 Ga. The magmatic zircons have positive εHf（t） values ranging from ＋0.40 to ＋7.60 and depleted mantle Hf model ages of 2.43-2.70 Ga, with major peaks at -2.54 and -2.65 Ga. The geochemical and Nd-Hf isotopic characteristics indicate that the Mohe quartz-dioritic rocks might be formed by partial melting of high-pressure metamorphosed juve- nile crustal rocks in post-orogenic extensional regime in the Early Paleoproterozoic. It suggests that important crustal growth occurred in the Quanji massif and the Tarim Craton at -2.4 and 2.5-2.7 Ga. The Quanji massif and Tarim Craton might share a similar crustal evolution history with the North China Craton in the Neoarchean.
文摘Y型模块化多电平换流器(modular multilevel converter in Y configuration,Y-MMC)的Y形结构,使其预充电及并网过程更为复杂,基于环流控制的一般启动策略不再适用。针对上述问题,设计基于模型预测控制的渐进预充电方法及无扰动并网方法,提出一种模型预测渐进启动控制策略。首先,建立桥臂电流和电容电压预测模型,通过模型预测控制改变充电电流回路、幅值和相角,实现可控充电最大有功输入,对各个桥臂渐进充电。其次,根据电流误差灵活投切子模块,逐渐平衡充电回路电势差,辅助模型预测控制抑制冲击电流。然后,协调外环比例积分控制与内环模型预测控制,通过切换外环功率和电压控制模式,实现基于Y-MMC的柔性低频输电系统无扰动并网过程。最后,通过Matlab/Simulink对双端柔性低频输电系统进行仿真分析,所提控制策略保障了启动过程较低的电流冲击和较高的充电速度,使系统平稳快速进入稳定运行状态。
