A fluorescent probe for the sensitive and selective determination of copper ion（Cu^2＋） is presented. It is based on the use of tungsten disulfide quantum dots（WS2 QDs） which is independent of the p H of solution ...A fluorescent probe for the sensitive and selective determination of copper ion（Cu^2＋） is presented. It is based on the use of tungsten disulfide quantum dots（WS2 QDs） which is independent of the p H of solution and emits strong blue fluorescence. Copper ions could cause aggregation of the WS2 QDs and lead to fluorescence quenching of WS2 QDs. The change of fluorescence intensity is proportional to the concentration of Cu^2＋, and the limit of detection is 0.4 μM. The fluorescent probe is highly selective for Cu^2＋ over some potentially interfering ions. These results indicate that WS2 QDs,as a fluorescent sensing platform, can meet the selective requirements for biomedical and environmental application.展开更多
The growth of fixed assets investment in China soared to a high record in the first quarter of 2004 after gross domestic product （GDP） bounced substantially in 2003. A bubble is emerging posing threats to Chinese ec...The growth of fixed assets investment in China soared to a high record in the first quarter of 2004 after gross domestic product （GDP） bounced substantially in 2003. A bubble is emerging posing threats to Chinese economic development. In order to cool down the overheated investment, Chinese government should promptly take effective measures in macroeconomic control to limit or guide the red-hot investment in some sectors and slow down its growth, thus implements the changes from administrative-driven investment to enterprise-driven investment and from investment-driven economic growth to consumption-driven growth.展开更多
This paper presents a novel Autonomous Integrity Monitoring and Assurance （AIMA） scheme for integrity assurance of the GNSS-based train integrated positioning system. In this scheme, integrity assurance strategies a...This paper presents a novel Autonomous Integrity Monitoring and Assurance （AIMA） scheme for integrity assurance of the GNSS-based train integrated positioning system. In this scheme, integrity assurance strategies are combined with a three-stage hierarchical architecture, considering the coupling effects among sensor collection, sensor fusion and matching decision level in train integrated positioning. In sensor collecting stage, the AIMA scheme deals with sensor faults and failures with a PCA-based fault detection, diagnosis and isolation approach. In multi-sensor fusion stage, a novel cubature point H0o filter is presented to enhance the fault tolerance capability, and a hybrid approach is applied to indicating and monitoring the protection level of position estimation, concerning both the estimating covariance and measurement slopes. In map matching stage, hypothesis testing with specific test statistic is carried out to determine effectiveness of positioning results. Position calculation will be invalid with an alarm triggered if the specific integrity criterion is not satisfied in any stage. Since independent solutions are applied in AIMA, integrity assurance is closely coupled with information processing in train integrated positioning. Numerical results of the three cases correspond to the hierarchical architecture with field data and simulations are presented to illustrate features and applicability of the proposed AIMA scheme and specific solutions.展开更多
基金supported by the National Basic Research Program,China(Grant Nos.2016YFA0202300 and 2016YFA0202302)the National Natural Science Foundation of China(Grant Nos.61527817,61335006,and 61378073)the Beijing Municipal Science and Technology Committee,China(Grant No.Z151100003315006)
文摘A fluorescent probe for the sensitive and selective determination of copper ion（Cu^2＋） is presented. It is based on the use of tungsten disulfide quantum dots（WS2 QDs） which is independent of the p H of solution and emits strong blue fluorescence. Copper ions could cause aggregation of the WS2 QDs and lead to fluorescence quenching of WS2 QDs. The change of fluorescence intensity is proportional to the concentration of Cu^2＋, and the limit of detection is 0.4 μM. The fluorescent probe is highly selective for Cu^2＋ over some potentially interfering ions. These results indicate that WS2 QDs,as a fluorescent sensing platform, can meet the selective requirements for biomedical and environmental application.
文摘The growth of fixed assets investment in China soared to a high record in the first quarter of 2004 after gross domestic product （GDP） bounced substantially in 2003. A bubble is emerging posing threats to Chinese economic development. In order to cool down the overheated investment, Chinese government should promptly take effective measures in macroeconomic control to limit or guide the red-hot investment in some sectors and slow down its growth, thus implements the changes from administrative-driven investment to enterprise-driven investment and from investment-driven economic growth to consumption-driven growth.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60634010, 60736047, 60870016)
文摘This paper presents a novel Autonomous Integrity Monitoring and Assurance （AIMA） scheme for integrity assurance of the GNSS-based train integrated positioning system. In this scheme, integrity assurance strategies are combined with a three-stage hierarchical architecture, considering the coupling effects among sensor collection, sensor fusion and matching decision level in train integrated positioning. In sensor collecting stage, the AIMA scheme deals with sensor faults and failures with a PCA-based fault detection, diagnosis and isolation approach. In multi-sensor fusion stage, a novel cubature point H0o filter is presented to enhance the fault tolerance capability, and a hybrid approach is applied to indicating and monitoring the protection level of position estimation, concerning both the estimating covariance and measurement slopes. In map matching stage, hypothesis testing with specific test statistic is carried out to determine effectiveness of positioning results. Position calculation will be invalid with an alarm triggered if the specific integrity criterion is not satisfied in any stage. Since independent solutions are applied in AIMA, integrity assurance is closely coupled with information processing in train integrated positioning. Numerical results of the three cases correspond to the hierarchical architecture with field data and simulations are presented to illustrate features and applicability of the proposed AIMA scheme and specific solutions.
