In order to investigate the feasibility of BDS/GPS in the deformation monitoring of long-span bridges,analysis and research on aspects like number of visible satellites,PDOP value and monitoring precision are carried ...In order to investigate the feasibility of BDS/GPS in the deformation monitoring of long-span bridges,analysis and research on aspects like number of visible satellites,PDOP value and monitoring precision are carried out. To analyze daily deformation characteristics of steel box girder bridge,observation data for 48 consecutive hours is computed by self-programmed software. Experiment results show that the monitoring-points on the bridge demonstrate obvious periodicity and recoverability in vertical and horizontal directions,meanwhile,changes in the elevation direction are relatively stable. The deformation-monitoring results of BDS/GPS combination system and GPS single system show good consistency. However,in a complex environment of the bridge,especially under the condition that satellite signals are severely affected,the advantages of BDS/GPS combination over GPS single system are more obvious.展开更多
This paper sets up a complete CO2 contact angle test system by a visualization autoclave, uses the hanging drop-method respectively getting the advancing angle and receding angle of CO2, on the shale surface under the...This paper sets up a complete CO2 contact angle test system by a visualization autoclave, uses the hanging drop-method respectively getting the advancing angle and receding angle of CO2, on the shale surface under the different temperature, and uses the Snake method measuring contact angle of droplet images, to make the wettability experimental study for CO2 on the shale surface. According to contact angle data, wettability of CO2 on the shale surface is preferable; the temperature is the higher, the wettability is better. At the same time, by analyzing correspondingly with scanning electron microscope images of shale sample, it is obtained that shale with different surface structures has affected wettability of CO2.展开更多
We present an innovative and practical scheme of building a miniaturized wavemeter, with the advantages of low cost, high reliability and simple structure. Through a calibration test by a 780 nm external cavity diode ...We present an innovative and practical scheme of building a miniaturized wavemeter, with the advantages of low cost, high reliability and simple structure. Through a calibration test by a 780 nm external cavity diode laser(ECDL), the results show that our system gets a wavelength resolution of better than 1 pm, measurement accuracy of better than 2 pm(corresponding to a frequency of 1 GHz), and a measurement range of 8.5 nm. Finally, the multi-mode comparison test between our system and a commercial spectrum analyzer further indicates the high-precision, miniaturization and low cost of the proposed system, which shows that it is particularly suitable for ECDL and atom cooling and trapping experiments. The system design, experimental results and conclusions are of definite significance as a fine reference for other ranges of wavelength.展开更多
基金Supported by the National Natural Science Foundation of China(No.41604018)Research Project of the Production and Research Institute of Jiangsu Province(No.2015002-04)
文摘In order to investigate the feasibility of BDS/GPS in the deformation monitoring of long-span bridges,analysis and research on aspects like number of visible satellites,PDOP value and monitoring precision are carried out. To analyze daily deformation characteristics of steel box girder bridge,observation data for 48 consecutive hours is computed by self-programmed software. Experiment results show that the monitoring-points on the bridge demonstrate obvious periodicity and recoverability in vertical and horizontal directions,meanwhile,changes in the elevation direction are relatively stable. The deformation-monitoring results of BDS/GPS combination system and GPS single system show good consistency. However,in a complex environment of the bridge,especially under the condition that satellite signals are severely affected,the advantages of BDS/GPS combination over GPS single system are more obvious.
基金Fund project： This Paper is funded by the National Natural Science Foundation of China （NO. 51076170）.
文摘This paper sets up a complete CO2 contact angle test system by a visualization autoclave, uses the hanging drop-method respectively getting the advancing angle and receding angle of CO2, on the shale surface under the different temperature, and uses the Snake method measuring contact angle of droplet images, to make the wettability experimental study for CO2 on the shale surface. According to contact angle data, wettability of CO2 on the shale surface is preferable; the temperature is the higher, the wettability is better. At the same time, by analyzing correspondingly with scanning electron microscope images of shale sample, it is obtained that shale with different surface structures has affected wettability of CO2.
基金supported by the National Natural Science Foundation of China(No.51275523)the Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20134307110009)+1 种基金the Graduate Innovative Research Fund of Hunan Province(No.CX20158015)the Excellent Graduate Innovative Fund of NUDT(No.B150305)
文摘We present an innovative and practical scheme of building a miniaturized wavemeter, with the advantages of low cost, high reliability and simple structure. Through a calibration test by a 780 nm external cavity diode laser(ECDL), the results show that our system gets a wavelength resolution of better than 1 pm, measurement accuracy of better than 2 pm(corresponding to a frequency of 1 GHz), and a measurement range of 8.5 nm. Finally, the multi-mode comparison test between our system and a commercial spectrum analyzer further indicates the high-precision, miniaturization and low cost of the proposed system, which shows that it is particularly suitable for ECDL and atom cooling and trapping experiments. The system design, experimental results and conclusions are of definite significance as a fine reference for other ranges of wavelength.
