A skip entry guidance algorithm blending numerical predictor-corrector and nominal trajectory tracking is presented for lunar return vehicles.The guidance is decoupled into longitudinal and lateral channels.A piecewis...A skip entry guidance algorithm blending numerical predictor-corrector and nominal trajectory tracking is presented for lunar return vehicles.The guidance is decoupled into longitudinal and lateral channels.A piecewise bank-vs-energy magnitude profile and a sign profile are adopted in the skip phase.A magnitude parameter is used to adjust the predicted downrange,and a pseudo-crossrange at the beginning of the final phase is selected as the lateral control variable.Prediction biases of both channels are nullified by a false position iteration algorithm.An on-line estimation and modeling method is introduced to compensate for aerodynamic and atmospheric uncertainties.A nominal trajectory for the final phase is generated based on actual reenter conditions,and the obtained nominal trajectory is tracked by a linear feedback law.A lateral corridor is used to manage the lateral state.The proposed guidance algorithm is assessed using three-degree-of-freedom Monte Carlo analyses,and the results show a satisfactory and robust performance under highly stressful dispersions.展开更多
The levee along middle and lower reaches of Yangtze, about 3 600 km long, was built mostly on loose quaternary deposit with changeful complicated formation and geologic defects. Hence, during flood season, dangerous e...The levee along middle and lower reaches of Yangtze, about 3 600 km long, was built mostly on loose quaternary deposit with changeful complicated formation and geologic defects. Hence, during flood season, dangerous events occur frequently, which imperil the levee’s safety and pose great threats to life and property of people behind the levee. According to the exploration and investigation results, a classification of subsoil profile is made. And then the analysis on main engineering geologic problems, i.e seepage failure of dyke and bank slope instability, is conducted. The internal relations between main engineering geologic problems and subsoil profile are found out, which provides a scientific basis for the design of strengthening dykes.展开更多
目的采用两种不同的方法进行人用疫苗生产用工作细胞库Vero细胞的鉴别,为提高人用疫苗生产用细胞的准确性及疫苗的安全性提供保障。方法采用短串联重复序列(short tandem repeat,STR)-PCR基因分型法对本所疫苗生产用Vero细胞的8个STR位...目的采用两种不同的方法进行人用疫苗生产用工作细胞库Vero细胞的鉴别,为提高人用疫苗生产用细胞的准确性及疫苗的安全性提供保障。方法采用短串联重复序列(short tandem repeat,STR)-PCR基因分型法对本所疫苗生产用Vero细胞的8个STR位点(D8S1106、D1S518、D6S1017、D17S1304、D4S2408、D5S1467、D19S245和DYS389)进行测定,并与文献报道的结果进行比对分析;采用染色体核型检查法,将Vero细胞经Giemsa染料染色,于显微镜下精确计数100个细胞的染色体后,统计染色体数为58或60条的细胞所占比例。结果 STR基因分型得到的特征性图谱与文献报道的结果完全相同,未出现三单位基因,且STR的重复数完全相同;高倍镜下精确计数100个细胞染色体数为58或60条的细胞所占比例为79%。结论本所疫苗生产用工作细胞库Vero细胞为正确细胞株,不存在污染或交叉污染的情况,为本所人用疫苗的安全性和准确性提供了保障。展开更多
基金supported by the National Natural Science Foundation of China(61203194)the Innovation Fund of National University of Defense Technology(B100101)
文摘A skip entry guidance algorithm blending numerical predictor-corrector and nominal trajectory tracking is presented for lunar return vehicles.The guidance is decoupled into longitudinal and lateral channels.A piecewise bank-vs-energy magnitude profile and a sign profile are adopted in the skip phase.A magnitude parameter is used to adjust the predicted downrange,and a pseudo-crossrange at the beginning of the final phase is selected as the lateral control variable.Prediction biases of both channels are nullified by a false position iteration algorithm.An on-line estimation and modeling method is introduced to compensate for aerodynamic and atmospheric uncertainties.A nominal trajectory for the final phase is generated based on actual reenter conditions,and the obtained nominal trajectory is tracked by a linear feedback law.A lateral corridor is used to manage the lateral state.The proposed guidance algorithm is assessed using three-degree-of-freedom Monte Carlo analyses,and the results show a satisfactory and robust performance under highly stressful dispersions.
文摘The levee along middle and lower reaches of Yangtze, about 3 600 km long, was built mostly on loose quaternary deposit with changeful complicated formation and geologic defects. Hence, during flood season, dangerous events occur frequently, which imperil the levee’s safety and pose great threats to life and property of people behind the levee. According to the exploration and investigation results, a classification of subsoil profile is made. And then the analysis on main engineering geologic problems, i.e seepage failure of dyke and bank slope instability, is conducted. The internal relations between main engineering geologic problems and subsoil profile are found out, which provides a scientific basis for the design of strengthening dykes.
文摘目的采用两种不同的方法进行人用疫苗生产用工作细胞库Vero细胞的鉴别,为提高人用疫苗生产用细胞的准确性及疫苗的安全性提供保障。方法采用短串联重复序列(short tandem repeat,STR)-PCR基因分型法对本所疫苗生产用Vero细胞的8个STR位点(D8S1106、D1S518、D6S1017、D17S1304、D4S2408、D5S1467、D19S245和DYS389)进行测定,并与文献报道的结果进行比对分析;采用染色体核型检查法,将Vero细胞经Giemsa染料染色,于显微镜下精确计数100个细胞的染色体后,统计染色体数为58或60条的细胞所占比例。结果 STR基因分型得到的特征性图谱与文献报道的结果完全相同,未出现三单位基因,且STR的重复数完全相同;高倍镜下精确计数100个细胞染色体数为58或60条的细胞所占比例为79%。结论本所疫苗生产用工作细胞库Vero细胞为正确细胞株,不存在污染或交叉污染的情况,为本所人用疫苗的安全性和准确性提供了保障。
