UWB signal digitization depends, to a large extent, on the accuracy of sampling time. A highaccuracy programmable timer is therefore the key to implementing UWB signal data acquisition. A high-accuracy programmable ti...UWB signal digitization depends, to a large extent, on the accuracy of sampling time. A highaccuracy programmable timer is therefore the key to implementing UWB signal data acquisition. A high-accuracy programmable timer based on the principle of ramp generators is described in this paper. The counting range of the timer is up to 16 bits, the timing precision is 8 ps, and the equivalent sampling rate is up to 50G Hz. No other identical product has been reported so far. This timer was successfully used in the data acquisition system for geological radar signals developed by us.展开更多
A three-dimensional positioning method for global positioning system(GPS)receivers based on three satellites was proposed.In the method,the measurement equation used for positioning calculation was expanded by means o...A three-dimensional positioning method for global positioning system(GPS)receivers based on three satellites was proposed.In the method,the measurement equation used for positioning calculation was expanded by means of two measures.In this case,the measurement equation could be solved,and the function of positioning calculation could be performed.The detailed steps of the method and how to evaluate the positioning precision of the method were given,respectively.The positioning performance of the method was demonstrated through some experiments.It is shown that the method can provide the three-dimensional positioning information under the condition that there are only three useful satellites.展开更多
Some insights and analysis are presented concerning the monitoring model of the VLBI(Very Long Baseline Interferometry) antenna,settings of parameters and selection of constraints to the observation equation,which are...Some insights and analysis are presented concerning the monitoring model of the VLBI(Very Long Baseline Interferometry) antenna,settings of parameters and selection of constraints to the observation equation,which are verified via data simulation analysis to be reasonable and effective.The effects of the number of targets and antenna orientations,the precision of target positioning observations,the observation outliers detection and deletion on the determination precision of antenna parameters are also analyzed,and some preliminary conclusions are given.展开更多
In this paper, we derive an upper bound for the adiabatic approximation error, which is the distance between the exact solution to a Schrodinger equation and the adiabatic approximation solution. As an application, we...In this paper, we derive an upper bound for the adiabatic approximation error, which is the distance between the exact solution to a Schrodinger equation and the adiabatic approximation solution. As an application, we obtain an upper bound for 1 minus the fidelity of the exact solution and the adiabatic approximation solution to a SchrOdinger equation.展开更多
Objective： To assess the correlation between five anthropometric parameters and the distance from tibial tuberosity to medial malleolus in 100 volunteers. Methods： Six anthropometric parameters were measured in 50 m...Objective： To assess the correlation between five anthropometric parameters and the distance from tibial tuberosity to medial malleolus in 100 volunteers. Methods： Six anthropometric parameters were measured in 50 male and 50 female medical students using a metallic scale： medial knee joint line to ankle joint line （K-A）, medial knee joint line to medial malleolus （K-MM）, tibial tuberosity to ankle joint （TT-A）, tibial tuberosity to medial malleolus （TT- MM）, olecranon to 5th metacarpal head （O-MH） and body height （BH）. Nail size predicted based upon Tr-MM measurement was chosen as ideal nail size. A constant was derived for each of the six anthropometric parameters which was either added or subtracted to each measurement to derive nail size. A regression equation was applied to BH measurements. Nail sizes calculated were compared with that obtained from TI＇-MM measurement and accuracy was evaluated. Accuracy of O-MH and BH regression equations recommended by other authors were calculated in our data. Results： Adding 11 mm to Tr-A distance had highest accuracy （81%） and correlation （0.966） in predicting nails correctly. Subtracting 33 mm from K-MM measurement and 25 mm from K-A distance derived accurate sizes in 69% and 76% respectively. Adding 6 mm to O-MH distance had a poor accuracy of 51%. Nail size prediction based upon body height regression equation derived correct nail sizes in only 34% of the cases. Regression equation analysis by other authors based on O-MH and BH distances yielded correct sizes in 11% and 5% of the cases respectively. Conclusion： TT-A, K-A and K-MM measurements can be used simultaneously to increase accuracy of nail size prediction. This method would be helpful in determining nail size preoperatively especially when one anatomic landmark is difficult to palpate.展开更多
基金This research is sponsored by National Natural Science Foundation of China,Special Fund of Scientific Instruments:The studyand development of flameproof ground penetrating radar (50127402).
文摘UWB signal digitization depends, to a large extent, on the accuracy of sampling time. A highaccuracy programmable timer is therefore the key to implementing UWB signal data acquisition. A high-accuracy programmable timer based on the principle of ramp generators is described in this paper. The counting range of the timer is up to 16 bits, the timing precision is 8 ps, and the equivalent sampling rate is up to 50G Hz. No other identical product has been reported so far. This timer was successfully used in the data acquisition system for geological radar signals developed by us.
基金Project (ZYGX2010J119)supported by the Fundamental Research Funds for the Central Universities of China
文摘A three-dimensional positioning method for global positioning system(GPS)receivers based on three satellites was proposed.In the method,the measurement equation used for positioning calculation was expanded by means of two measures.In this case,the measurement equation could be solved,and the function of positioning calculation could be performed.The detailed steps of the method and how to evaluate the positioning precision of the method were given,respectively.The positioning performance of the method was demonstrated through some experiments.It is shown that the method can provide the three-dimensional positioning information under the condition that there are only three useful satellites.
基金supported by the National Natural Sciences Foundation of China(Grant Nos.11178024 and 10973030)the Lunar Exploration of China(Chang’E 2 and 3)+1 种基金the Committee of Sciences and Technology of Shanghai(Grant No.06DZ22101)the National High Technology Research and Development Program of China(Grant No.2012AA121603)
文摘Some insights and analysis are presented concerning the monitoring model of the VLBI(Very Long Baseline Interferometry) antenna,settings of parameters and selection of constraints to the observation equation,which are verified via data simulation analysis to be reasonable and effective.The effects of the number of targets and antenna orientations,the precision of target positioning observations,the observation outliers detection and deletion on the determination precision of antenna parameters are also analyzed,and some preliminary conclusions are given.
基金supported by the National Natural Science Fundation of China(Grant No.11171197)the Fundamental Research Funds for the Central Universities(Grant No.GK201301007)the Innovation Fund Project for Graduate Program of Shaanxi Normal University(Grant No.2013CXB012)
文摘In this paper, we derive an upper bound for the adiabatic approximation error, which is the distance between the exact solution to a Schrodinger equation and the adiabatic approximation solution. As an application, we obtain an upper bound for 1 minus the fidelity of the exact solution and the adiabatic approximation solution to a SchrOdinger equation.
文摘Objective： To assess the correlation between five anthropometric parameters and the distance from tibial tuberosity to medial malleolus in 100 volunteers. Methods： Six anthropometric parameters were measured in 50 male and 50 female medical students using a metallic scale： medial knee joint line to ankle joint line （K-A）, medial knee joint line to medial malleolus （K-MM）, tibial tuberosity to ankle joint （TT-A）, tibial tuberosity to medial malleolus （TT- MM）, olecranon to 5th metacarpal head （O-MH） and body height （BH）. Nail size predicted based upon Tr-MM measurement was chosen as ideal nail size. A constant was derived for each of the six anthropometric parameters which was either added or subtracted to each measurement to derive nail size. A regression equation was applied to BH measurements. Nail sizes calculated were compared with that obtained from TI＇-MM measurement and accuracy was evaluated. Accuracy of O-MH and BH regression equations recommended by other authors were calculated in our data. Results： Adding 11 mm to Tr-A distance had highest accuracy （81%） and correlation （0.966） in predicting nails correctly. Subtracting 33 mm from K-MM measurement and 25 mm from K-A distance derived accurate sizes in 69% and 76% respectively. Adding 6 mm to O-MH distance had a poor accuracy of 51%. Nail size prediction based upon body height regression equation derived correct nail sizes in only 34% of the cases. Regression equation analysis by other authors based on O-MH and BH distances yielded correct sizes in 11% and 5% of the cases respectively. Conclusion： TT-A, K-A and K-MM measurements can be used simultaneously to increase accuracy of nail size prediction. This method would be helpful in determining nail size preoperatively especially when one anatomic landmark is difficult to palpate.
