No abstract

The authors discuss the genesis of the regional gravity and magnetic anomalies in the northern part of Eastern Xinjiang, a correlation analysis was carried out between the regional gravity anomaly and the regional magnetic anomaly. Through data processing and integrated interpretation of the gravity and magnetic data in the study area, the Bouguer gravity anomaly and the magnetic anomaly by reduction to the pole were separated. Then, the regional gravity and magnetic anomalies across multiple scales were extracted; in addition, the correlation coefficients between the regional gravity anomaly and the regional magnetic anomaly at different scales were calculated. Finally, the features of the gravity and magnetic fields, their geological significance, and the origins of these regional gravity and magnetic anomalies were analyzed. The results showed that the regional negative gravity anomaly in the Turpan-Hami basin and the Santanghu basin was mainly caused by Cenozoic and Mesozoic strata; the regional positive magnetic anomaly was mainly caused by the Precambrian metamorphic basement. The study revealed that the regional positive gravity and magnetic anomalies resulted from the crust and the mantle substances in the eastern part of the Junggar basin. While the regional positive gravity anomaly was mainly caused by Pre-Mesozoic strata, and the regional negative magnetic anomaly by the sedimentary formation and intermediate acid rocks in the Bogeda-Harlike folded zone and the Jueluotage anticlinorium. The regional negative gravity and magnetic anomalies in the active zone of the northern margin of Tarim were mainly caused by the sedimentary formation and intermediate acid rocks.

Stimulated emission depletion (STED) microscopy performed using continuous-wave (CW) lasers has been investigated and developed by Willig et al. (Nature Methods, 2007, 4(11):915) for nearly a decade. Kuang et al. (Review of Scientific Instruments, 2010, 81:053709) developed the CW STED microscopy technique with 405 nm excitation and 532 nm depletion beams. In their research, Coumarin 102 dye was adopted and was found to be depletable. In this study, a parametric investigation of the depletion of Coumarin 102 dye is carried out experimentally. The influence of the excitation and depletion beam intensities and dye concentrations on the depletion efficiency are studied in detail. The results indicate the following: (1) The highest depletion occurs for the 100 μM Coumarin 102 solution, with a 1.4 μW excitation beam and a 115.3 mW depletion beam. (2) The minimum saturation intensity (Is) of STED, that is 13 MW cm , is observed when the Coumarin 102 solution concentration is 10 μM. (3) Is values calculated directly from the depletion power derived with the cross-sectional area due to the full-width-at-half-maximum (FWHM) of the depletion beam show poor accuracy, where Is may be overestimated. Thus, a correction factor for the cross-sectional area is proposed. We also find that Is is not exactly constant for a fixed excitation beam power and dye concentration. This trend indicates that the conventional suppression function η(x)=e- ln (2)ISTED(x)/Is derived from picosecond STED may cause errors in evaluating the depletion process in CW STED microscopy.