A heavy rainfall event in south China was simulated by the Weather Research and Forecasting(WRF) model with three microphysics schemes, including the Morrison scheme, Thompson scheme, and Milbrandt and Yau scheme(MY),...A heavy rainfall event in south China was simulated by the Weather Research and Forecasting(WRF) model with three microphysics schemes, including the Morrison scheme, Thompson scheme, and Milbrandt and Yau scheme(MY), which aim to evaluate the capability to reproduce the precipitation and radar echo reflectivity features, and to evaluate evaluate their differences in microphysics and the associated thermodynamical and dynamical feedback. Results show that all simulations reproduce the main features crucial for rainfall formation. Compared with the observation, the MY scheme performed better than the other two schemes in terms of intensity and spatial distribution of rainfall. Due to abundant water vapor, the accretion of cloud droplets by raindrops was the dominant process in the growth of raindrops while the contribution of melting was a secondary effect. Riming processes, in which frozen hydrometeors collect cloud droplets mainly, contributed more to the growth of frozen hydrometeors than the Bergeron process. Extremely abundant snow and ice were produced in the Thompson and MY schemes respectively by a deposition process. The MY scheme has the highest condensation and evaporation, but the lowest deposition. As a result, in the MY scheme, the enhanced vertical gradient of condensation heating and evaporation cooling at low levels produces strong positive and weak negative potential vorticity in Guangdong, and may favor the formation of the enhanced rainfall center over there.展开更多
The time series data of silicon content in hot metal were identified to have the chaotic feature because of the positive maximum Lyapunov exponent, and then the time scales to predict future were estimated. Finally a ...The time series data of silicon content in hot metal were identified to have the chaotic feature because of the positive maximum Lyapunov exponent, and then the time scales to predict future were estimated. Finally a chaotic local-region model was constructed to predict silicon content in hot metal with good performance due to high hitting rate.展开更多
目的分析红细胞分布宽度(RDW)在原发性高血压患者与血压变异性(BPV)的相关性。方法回顾性分析2017年10月~2019年6月北京市西城区平安医院收治的220例原发性高血压患者的临床资料。监测所有受试者24 h动态血压,测定血清RDW和血脂等生化...目的分析红细胞分布宽度(RDW)在原发性高血压患者与血压变异性(BPV)的相关性。方法回顾性分析2017年10月~2019年6月北京市西城区平安医院收治的220例原发性高血压患者的临床资料。监测所有受试者24 h动态血压,测定血清RDW和血脂等生化指标。根据RDW四分位值将患者分为4组:Ⅰ组58例(RDW<12.40%)、Ⅱ组56例(12.40%≤RDW<12.90%)、Ⅲ组52例(12.90%≤RDW<13.50%)、Ⅳ组54例(RDW≥13.50%)。本研究以24 h动态血压读数的标准差作为BPV指标[包括24 h收缩压标准差(24 h SSD)、24 h舒张压标准差(24 h DSD)],比较不同RDW水平患者的BPV情况,分析RDW与BPV的相关性。结果BPV指标比较结果显示,24 h SSD、24 h DSD在Ⅳ组高于Ⅲ组、Ⅲ组高于Ⅱ组、Ⅱ组高于Ⅰ组,差异有统计学意义(P<0.05)。Pearson相关性分析结果显示,RDW与24 h SSD、24 h DSD呈正相关(r=0.727、0.557,P<0.05)。结论原发性高血压患者RDW水平与BPV呈正相关,RDW与原发性高血压患者BPV密切相关。展开更多
基金National Natural Science Foundation of China(42230612,41905071,41620104009)。
文摘A heavy rainfall event in south China was simulated by the Weather Research and Forecasting(WRF) model with three microphysics schemes, including the Morrison scheme, Thompson scheme, and Milbrandt and Yau scheme(MY), which aim to evaluate the capability to reproduce the precipitation and radar echo reflectivity features, and to evaluate evaluate their differences in microphysics and the associated thermodynamical and dynamical feedback. Results show that all simulations reproduce the main features crucial for rainfall formation. Compared with the observation, the MY scheme performed better than the other two schemes in terms of intensity and spatial distribution of rainfall. Due to abundant water vapor, the accretion of cloud droplets by raindrops was the dominant process in the growth of raindrops while the contribution of melting was a secondary effect. Riming processes, in which frozen hydrometeors collect cloud droplets mainly, contributed more to the growth of frozen hydrometeors than the Bergeron process. Extremely abundant snow and ice were produced in the Thompson and MY schemes respectively by a deposition process. The MY scheme has the highest condensation and evaporation, but the lowest deposition. As a result, in the MY scheme, the enhanced vertical gradient of condensation heating and evaporation cooling at low levels produces strong positive and weak negative potential vorticity in Guangdong, and may favor the formation of the enhanced rainfall center over there.
文摘The time series data of silicon content in hot metal were identified to have the chaotic feature because of the positive maximum Lyapunov exponent, and then the time scales to predict future were estimated. Finally a chaotic local-region model was constructed to predict silicon content in hot metal with good performance due to high hitting rate.
文摘目的分析红细胞分布宽度(RDW)在原发性高血压患者与血压变异性(BPV)的相关性。方法回顾性分析2017年10月~2019年6月北京市西城区平安医院收治的220例原发性高血压患者的临床资料。监测所有受试者24 h动态血压,测定血清RDW和血脂等生化指标。根据RDW四分位值将患者分为4组:Ⅰ组58例(RDW<12.40%)、Ⅱ组56例(12.40%≤RDW<12.90%)、Ⅲ组52例(12.90%≤RDW<13.50%)、Ⅳ组54例(RDW≥13.50%)。本研究以24 h动态血压读数的标准差作为BPV指标[包括24 h收缩压标准差(24 h SSD)、24 h舒张压标准差(24 h DSD)],比较不同RDW水平患者的BPV情况,分析RDW与BPV的相关性。结果BPV指标比较结果显示,24 h SSD、24 h DSD在Ⅳ组高于Ⅲ组、Ⅲ组高于Ⅱ组、Ⅱ组高于Ⅰ组,差异有统计学意义(P<0.05)。Pearson相关性分析结果显示,RDW与24 h SSD、24 h DSD呈正相关(r=0.727、0.557,P<0.05)。结论原发性高血压患者RDW水平与BPV呈正相关,RDW与原发性高血压患者BPV密切相关。
