The transient Rayleigh wave exploration has high detection accuracy in shallow exploration. The effect of detection array is comprehensive reflection of the velocity of rock and soil mass. Therefore, the roiling multi...The transient Rayleigh wave exploration has high detection accuracy in shallow exploration. The effect of detection array is comprehensive reflection of the velocity of rock and soil mass. Therefore, the roiling multi-channel transient acquisition system has been adopted in this study, which turns one dimensional transient Rayleigh wave exploration into two dimensions, consequently, the two-dimensional velocity distribution of rock and soil mass under the survey line has been achieved. Through comparing with the shallow seismic reflected wave exploration, the result indicates that the rolling multi-channel transient acquisition system has accurate resolution. Thus, in the process of the shallow reflected wave exploration, if the surface wave has developed, the coalition between the reflected wave exploration and the two-dimensional transient Rayleigh wave exploration should actualize the accuracy of exploration.展开更多
This research describes an integrated multi-channel high accuracy current control LED （light emitting diode） driver with low dropout regulator implemented in a 0.35μm TSMC 2P4M CMOS process. With the new trend of b...This research describes an integrated multi-channel high accuracy current control LED （light emitting diode） driver with low dropout regulator implemented in a 0.35μm TSMC 2P4M CMOS process. With the new trend of backlighting applications for mobile electronics and portable devices requiring a smaller size, lower cost, lesser noise and accurate current control LED driver, it came up with the idea of integrating more than one design features within a single chip. The analysis of using a capacitor-less low dropout regulator to power the constant current source has been explored, with the implementation of wide range battery voltage of 3 V to 5 V. Possible load current variations were introduced and verified to output a fixed voltage of 2.8 V. A regulated cascode current mirror structure forms the multi-channel configuration string of LED＇s; the design ensures a current matching of less than 1% error and achieves a high accuracy current control of less than 1% error, regardless of the LED＇s forward voltage variation. Moreover, for high end portable device with multimedia applications, dimming frequency can be set to 10 MHz. In addition, a switching output is a better approach for managing LED＇s contrast and brightness adjustment as well as maximizing power consumption, ensuring longer life for driving string of LEDs.展开更多
利用微波辐射传输模型PWR(P. W. Rosenkranz)和反向传播神经网络方法,分别构建了正演下行辐射亮温和反演大气相对湿度廓线的模型,并研究了晴空条件下高光谱微波辐射计反演大气相对湿度廓线的通道选择问题。研究结果表明,200个通道的信...利用微波辐射传输模型PWR(P. W. Rosenkranz)和反向传播神经网络方法,分别构建了正演下行辐射亮温和反演大气相对湿度廓线的模型,并研究了晴空条件下高光谱微波辐射计反演大气相对湿度廓线的通道选择问题。研究结果表明,200个通道的信息含量大于微波辐射计7个通道的信息含量;增加探测通道数量可提升大气相对湿度廓线的反演精度,选取信息含量排在前面的120个通道进行仿真时,在0～2 km和6～10 km高度范围内大气相对湿度廓线的反演精度提升了4%～10%,在2～6 km高度范围内的相对湿度廓线的反演精度提升了约10%;当通道数继续增加时,反演精度的提升并不明显。展开更多
Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the lim...Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency.展开更多
The analysis of accuracy for superposition of squeezed states （SSSs） in lossless and loss case has been performed in this study. In lossless case, time accuracies of SSSs with mean photon number ns have a scaling of...The analysis of accuracy for superposition of squeezed states （SSSs） in lossless and loss case has been performed in this study. In lossless case, time accuracies of SSSs with mean photon number ns have a scaling of ns-2 in two limits of large and small squeezing. With the help of photon loss model, the dissipative channel will degrade accuracies has been proved. In the limit of large squeezing, the accuracy will slowly decrease with the reduction of transmittance η. In the limit of small squeezing, time accuracy scales as 1/（η4n2） and will decrease much faster along with η decreases.展开更多
文摘The transient Rayleigh wave exploration has high detection accuracy in shallow exploration. The effect of detection array is comprehensive reflection of the velocity of rock and soil mass. Therefore, the roiling multi-channel transient acquisition system has been adopted in this study, which turns one dimensional transient Rayleigh wave exploration into two dimensions, consequently, the two-dimensional velocity distribution of rock and soil mass under the survey line has been achieved. Through comparing with the shallow seismic reflected wave exploration, the result indicates that the rolling multi-channel transient acquisition system has accurate resolution. Thus, in the process of the shallow reflected wave exploration, if the surface wave has developed, the coalition between the reflected wave exploration and the two-dimensional transient Rayleigh wave exploration should actualize the accuracy of exploration.
文摘This research describes an integrated multi-channel high accuracy current control LED （light emitting diode） driver with low dropout regulator implemented in a 0.35μm TSMC 2P4M CMOS process. With the new trend of backlighting applications for mobile electronics and portable devices requiring a smaller size, lower cost, lesser noise and accurate current control LED driver, it came up with the idea of integrating more than one design features within a single chip. The analysis of using a capacitor-less low dropout regulator to power the constant current source has been explored, with the implementation of wide range battery voltage of 3 V to 5 V. Possible load current variations were introduced and verified to output a fixed voltage of 2.8 V. A regulated cascode current mirror structure forms the multi-channel configuration string of LED＇s; the design ensures a current matching of less than 1% error and achieves a high accuracy current control of less than 1% error, regardless of the LED＇s forward voltage variation. Moreover, for high end portable device with multimedia applications, dimming frequency can be set to 10 MHz. In addition, a switching output is a better approach for managing LED＇s contrast and brightness adjustment as well as maximizing power consumption, ensuring longer life for driving string of LEDs.
基金supported by the National Natural Science Foundation of China (Grant No. 40971227)the International Corporation Program of Science and Technology Ministry of China (Grant No. 2010DFA21880)
文摘Based on the conduction and transformation of the thermal infrared radiative transfer equation of water target,a twinchannel difference model(DM) was proposed to improve the calibration precision by conquering the limitation that the atmospheric condition when image is acquiring cannot be truly obtained in the traditional radiometric simulation calibration method.The analysis of surface,atmosphere and top-of-atmosphere(TOA) radiative energy decomposition demonstrated that the apparent TOA radiance of the uncalibrated channel is the differential combination of two reference channels.The DM avoids impacts from atmospheric temperature and density.The only impact is from water vapor(WV) content.Based on the fitting error analysis of 742 mid-latitude atmospheric profiles(column WV content:0-5×10 3 atm cm) selected from TIGR database,the DM is insensitive to WV content.The maximum error is less than 0.2 K when the view zenith angels(VZAs) of reference channels and uncalibrated channel are less than 30.The error becomes 0.3 K when VZAs range from 30 to 40 and 0.6 K when VZAs are in 40-50.Because the uncertainty increases when VZAs are larger than 50,the best range of VZAs is 30-50.The vicarious calibration results at Lake Qinghai field indicated that the calibration precision of the DM cross-calibration by using MODIS bands 31 and 32 as reference channels to calibrate IRS band 08 is similar to that of vicarious calibration.Therefore,the DM is a reliable alternative tool for sensor on-orbit calibration and validation with high precision and frequency.
基金supported by the National Natural Science Foundation of China (Grant No. 61075014)the Science Foundation of Xi’an University of Posts and Telecommunications for Young Teachers (Grant No.ZL2010-11)the Science Foundation of Shaanxi Provincial Department of Education (Grant No. 11JK0902)
文摘The analysis of accuracy for superposition of squeezed states （SSSs） in lossless and loss case has been performed in this study. In lossless case, time accuracies of SSSs with mean photon number ns have a scaling of ns-2 in two limits of large and small squeezing. With the help of photon loss model, the dissipative channel will degrade accuracies has been proved. In the limit of large squeezing, the accuracy will slowly decrease with the reduction of transmittance η. In the limit of small squeezing, time accuracy scales as 1/（η4n2） and will decrease much faster along with η decreases.
