This paper proposed a new libration decoupling analytical speed function(LD-ASF)in lieu of the classic analytical speed function to control the climber's speed along a partial space elevator to improve libration s...This paper proposed a new libration decoupling analytical speed function(LD-ASF)in lieu of the classic analytical speed function to control the climber's speed along a partial space elevator to improve libration stability in cargo transportation.The LD-ASF is further optimized for payload transportation efficiency by a novel coordinate game theory to balance competing control objectives among payload transport speed,stable end body's libration,and overall control input via model predictive control.The transfer period is divided into several sections to reduce computational burden.The validity and efficacy of the proposed LD-ASF and coordinate game-based model predictive control are demonstrated by computer simulation.Numerical results reveal that the optimized LD-ASF results in higher transportation speed,stable end body's libration,lower thrust fuel consumption,and more flexible optimization space than the classic analytical speed function.展开更多
Beamspace super-resolution methods for elevation estimation in multipath environment has attracted significant attention, especially the beamspace maximum likelihood(BML)algorithm. However, the difference beam is rare...Beamspace super-resolution methods for elevation estimation in multipath environment has attracted significant attention, especially the beamspace maximum likelihood(BML)algorithm. However, the difference beam is rarely used in superresolution methods, especially in low elevation estimation. The target airspace information in the difference beam is different from the target airspace information in the sum beam. And the use of difference beams does not significantly increase the complexity of the system and algorithms. Thus, this paper applies the difference beam to the beamformer to improve the elevation estimation performance of BML algorithm. And the direction and number of beams can be adjusted according to the actual needs. The theoretical target elevation angle root means square error(RMSE) and the computational complexity of the proposed algorithms are analyzed. Finally, computer simulations and real data processing results demonstrate the effectiveness of the proposed algorithms.展开更多
目的分析非ST段抬高型心肌梗死(non-ST-segment elevation myocardial infarction,NSTEMI)患者和ST段抬高型心肌梗死(ST-elevated myocardial infarction,STEMI)患者血小板与淋巴细胞比值(platelet to lymphocyte ratio,PLR)、中性粒细...目的分析非ST段抬高型心肌梗死(non-ST-segment elevation myocardial infarction,NSTEMI)患者和ST段抬高型心肌梗死(ST-elevated myocardial infarction,STEMI)患者血小板与淋巴细胞比值(platelet to lymphocyte ratio,PLR)、中性粒细胞与淋巴细胞比值(neutrophil to lymphocyte ratio,NLR)、淋巴细胞与单核细胞比值(lymphocyte to monocyte ratio,LMR)及凝血功能指标检测的意义。方法选择2021年1月至2023年12月蚌埠市第三人民医院心血管内科收治的老年(>60岁)急性心肌梗死患者182例,根据心电图特征分为NSTEMI组104例和STEMI组78例,另选取同期于蚌埠市第三人民医院体检的健康者80例作为对照组。入院后检测所有受试者的PLR、NLR、LMR、D-二聚体及纤维蛋白原(fibrinogen,FIB)水平。对比3组血清PLR、NLR、LMR、D-二聚体、FIB水平,采用二元logistic回归分析法构建基于PLR、NLR、LMR、D-二聚体、FIB的评估模型,以ROC曲线分析PLR、NLR、LMR、D-二聚体、FIB评估NSTEMI与STEMI患者的价值。结果STEMI组和NSTEMI组的血清PLR、NLR、LMR、D-二聚体、FIB水平明显高于对照组(P<0.05)。血清PLR、NLR、LMR、D-二聚体、FIB水平为STEMI和NSTEMI患者的独立影响因子(OR=25.078,95%CI:3.147~199.865;OR=32.852,95%CI:4.398~245.417;OR=28.703,95%CI:3.310~248.867,OR=67.491,95%CI:8.518~534.729;OR=46.759,95%CI:8.219~266.006;OR=2.573,95%CI:1.026~6.451;OR=3.442,95%CI:1.750~6.768,OR=2.971,95%CI:1.799~4.907;OR=68.375,95%CI:12.598~371.103;OR=7.471,95%CI:1.759~31.737,P<0.01)。ROC曲线显示,血清PLR、NLR、LMR、D-二聚体、FIB联合评估NSTEMI的曲线下面积(area under curve,AUC)为0.996,敏感性为99.04%,特异性为95.00%;联合评估STEMI的AUC为0.995,敏感性为94.87%,特异性为97.50%,效能优于各指标单独评估(P<0.05)。结论NSTEMI患者与STEMI患者的PLR、NLR、LMR、D-二聚体、FIB水平明显升高,各指标联合测定对于NSTEMI和STEMI的早期诊断具有重要的参考价值。展开更多
为了研究高温和应变率对超高性能混凝土(UHPC)劈裂抗拉性能的影响,对不同温度(20、105、200、300、400℃)作用后UHPC的质量损失率、抗压强度、弹性模量、静态和动态(应变率为1.8~6.8 s^(-1))劈裂抗拉强度进行了测试.结果表明:以2~10℃/...为了研究高温和应变率对超高性能混凝土(UHPC)劈裂抗拉性能的影响,对不同温度(20、105、200、300、400℃)作用后UHPC的质量损失率、抗压强度、弹性模量、静态和动态(应变率为1.8~6.8 s^(-1))劈裂抗拉强度进行了测试.结果表明:以2~10℃/min的加热速率升温至400℃后,所有试件均在保温期间发生爆裂性剥落;U H P C的抗压强度、弹性模量、静态劈裂抗拉强度均随温度增大而提高,300℃作用后比常温时分别提高了13.2%、19.1%和17.3%;动态劈裂抗拉强度和耗散能均具有明显的应变率效应,当应变率从1.8~2.2 s^(-1)增加到6.3~6.8 s^(-1)时,20~300℃作用后的UHPC动态劈裂抗拉强度和耗散能分别提高了69.1%~74.1%和146.7%~177.6%;高温作用后UHPC中C-S-H表面的吸附水、孔隙内自由水和凝胶结合水先后分解,增大了试件的质量损失率;基体内高温和高压环境促进了水泥水化反应和硅灰火山灰反应,提升了UHPC的致密程度,增强了钢纤维的桥连作用;在冲击荷载作用下,基体开裂速度的加快和由钢纤维拔出所致基体摩擦效应的增强导致耗散能增大.展开更多
基金funded by the National Natural Science Foundation of China(12102487)Basic and Applied Basic Research Foundation of Guangdong Province,China(2023A1515012339)+1 种基金Shenzhen Science and Technology Program(ZDSYS20210623091808026)the Discovery Grant(RGPIN-2024-06290)of the Natural Sciences and Engineering Research Council of Canada。
文摘This paper proposed a new libration decoupling analytical speed function(LD-ASF)in lieu of the classic analytical speed function to control the climber's speed along a partial space elevator to improve libration stability in cargo transportation.The LD-ASF is further optimized for payload transportation efficiency by a novel coordinate game theory to balance competing control objectives among payload transport speed,stable end body's libration,and overall control input via model predictive control.The transfer period is divided into several sections to reduce computational burden.The validity and efficacy of the proposed LD-ASF and coordinate game-based model predictive control are demonstrated by computer simulation.Numerical results reveal that the optimized LD-ASF results in higher transportation speed,stable end body's libration,lower thrust fuel consumption,and more flexible optimization space than the classic analytical speed function.
基金supported by the Fund for Foreign Scholars in University Research and Teaching Programs (B18039)。
文摘Beamspace super-resolution methods for elevation estimation in multipath environment has attracted significant attention, especially the beamspace maximum likelihood(BML)algorithm. However, the difference beam is rarely used in superresolution methods, especially in low elevation estimation. The target airspace information in the difference beam is different from the target airspace information in the sum beam. And the use of difference beams does not significantly increase the complexity of the system and algorithms. Thus, this paper applies the difference beam to the beamformer to improve the elevation estimation performance of BML algorithm. And the direction and number of beams can be adjusted according to the actual needs. The theoretical target elevation angle root means square error(RMSE) and the computational complexity of the proposed algorithms are analyzed. Finally, computer simulations and real data processing results demonstrate the effectiveness of the proposed algorithms.
文摘目的分析非ST段抬高型心肌梗死(non-ST-segment elevation myocardial infarction,NSTEMI)患者和ST段抬高型心肌梗死(ST-elevated myocardial infarction,STEMI)患者血小板与淋巴细胞比值(platelet to lymphocyte ratio,PLR)、中性粒细胞与淋巴细胞比值(neutrophil to lymphocyte ratio,NLR)、淋巴细胞与单核细胞比值(lymphocyte to monocyte ratio,LMR)及凝血功能指标检测的意义。方法选择2021年1月至2023年12月蚌埠市第三人民医院心血管内科收治的老年(>60岁)急性心肌梗死患者182例,根据心电图特征分为NSTEMI组104例和STEMI组78例,另选取同期于蚌埠市第三人民医院体检的健康者80例作为对照组。入院后检测所有受试者的PLR、NLR、LMR、D-二聚体及纤维蛋白原(fibrinogen,FIB)水平。对比3组血清PLR、NLR、LMR、D-二聚体、FIB水平,采用二元logistic回归分析法构建基于PLR、NLR、LMR、D-二聚体、FIB的评估模型,以ROC曲线分析PLR、NLR、LMR、D-二聚体、FIB评估NSTEMI与STEMI患者的价值。结果STEMI组和NSTEMI组的血清PLR、NLR、LMR、D-二聚体、FIB水平明显高于对照组(P<0.05)。血清PLR、NLR、LMR、D-二聚体、FIB水平为STEMI和NSTEMI患者的独立影响因子(OR=25.078,95%CI:3.147~199.865;OR=32.852,95%CI:4.398~245.417;OR=28.703,95%CI:3.310~248.867,OR=67.491,95%CI:8.518~534.729;OR=46.759,95%CI:8.219~266.006;OR=2.573,95%CI:1.026~6.451;OR=3.442,95%CI:1.750~6.768,OR=2.971,95%CI:1.799~4.907;OR=68.375,95%CI:12.598~371.103;OR=7.471,95%CI:1.759~31.737,P<0.01)。ROC曲线显示,血清PLR、NLR、LMR、D-二聚体、FIB联合评估NSTEMI的曲线下面积(area under curve,AUC)为0.996,敏感性为99.04%,特异性为95.00%;联合评估STEMI的AUC为0.995,敏感性为94.87%,特异性为97.50%,效能优于各指标单独评估(P<0.05)。结论NSTEMI患者与STEMI患者的PLR、NLR、LMR、D-二聚体、FIB水平明显升高,各指标联合测定对于NSTEMI和STEMI的早期诊断具有重要的参考价值。
文摘为了研究高温和应变率对超高性能混凝土(UHPC)劈裂抗拉性能的影响,对不同温度(20、105、200、300、400℃)作用后UHPC的质量损失率、抗压强度、弹性模量、静态和动态(应变率为1.8~6.8 s^(-1))劈裂抗拉强度进行了测试.结果表明:以2~10℃/min的加热速率升温至400℃后,所有试件均在保温期间发生爆裂性剥落;U H P C的抗压强度、弹性模量、静态劈裂抗拉强度均随温度增大而提高,300℃作用后比常温时分别提高了13.2%、19.1%和17.3%;动态劈裂抗拉强度和耗散能均具有明显的应变率效应,当应变率从1.8~2.2 s^(-1)增加到6.3~6.8 s^(-1)时,20~300℃作用后的UHPC动态劈裂抗拉强度和耗散能分别提高了69.1%~74.1%和146.7%~177.6%;高温作用后UHPC中C-S-H表面的吸附水、孔隙内自由水和凝胶结合水先后分解,增大了试件的质量损失率;基体内高温和高压环境促进了水泥水化反应和硅灰火山灰反应,提升了UHPC的致密程度,增强了钢纤维的桥连作用;在冲击荷载作用下,基体开裂速度的加快和由钢纤维拔出所致基体摩擦效应的增强导致耗散能增大.
