A mei-yu front process in the lower reaches of the Yangtze River on 23 June 1999 was simulated by using the fifth-generation Pennsylvania State University-NCAR （PSU/NCAR） Mesoscale Model （MM5） with FDDA （Four Dim...A mei-yu front process in the lower reaches of the Yangtze River on 23 June 1999 was simulated by using the fifth-generation Pennsylvania State University-NCAR （PSU/NCAR） Mesoscale Model （MM5） with FDDA （Four Dimension Data Assimilation）. The analysis shows that seven weak small mesoscale vortexes of tens of kilometers, correspondent to surface low trough or mesoscale centers, in the planetary boundary layer （PBL） in the mei-yu front were heavily responsible for the heavy rainfall. Sometimes, several weak small-scale vortexes in the PBL could form a vortex group, some of which would weaken locally, and some would develop to be a meso-α-scale low vortex through combination. The initial dynamical triggering mechanism was related to two strong currents： one was the northeast flow in the PBL at the rear of the mei-yu front, the vortexes occurred exactly at the side of the northeast flow; and the other was the strong southwest low-level jet （LLJ） in front of the Mei-yu front, which moved to the upper of the vortexes. Consequently, there were notable horizontal and vertical wind shears to form positive vorticity in the center of the southwest LLJ. The development of mesoscale convergence in the PBL and divergence above, as well as the vertical positive vorticity column, were related to the small wind column above the nose-shaped velocity contours of the northeast flow embedding southwestward in the PBL, which intensified the horizontal wind shear and the positive vorticity column above the vortexes, baroclinicity and instability.展开更多
With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic field.At a low-order two-scale expansion,applying the mode coupling approximation in the Ya...With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic field.At a low-order two-scale expansion,applying the mode coupling approximation in the Yakhot-Orszag renormalization group method to analyze the fluctuating field,the Reynolds-average terms in the Reynolds stress transport equation,such as the convective term,the pressure-gradient-velocity correlation term and the dissipation term,are modeled.Two numerical examples：turbulent flow past a backward-facing step and the fully developed flow in a rotating channel,are presented for testing the efficiency of the proposed second-order model.For these two numerical examples,the proposed model performs as well as the Gibson-Launder （GL） model,giving better prediction than the standard k-ε model,especially in the abilities to calculate the secondary flow in the backward-facing step flow and to capture the asymmetric turbulent structure caused by frame rotation.展开更多
目的探讨团体绘画治疗对恢复期精神分裂症住院患者阴性和阳性症状、社会功能和认知功能的影响,为患者提供非药物治疗方法。方法将2022年1月至9月45例本院住院恢复期精神分裂症患者设为对照组,并予以常规药物及康复训练;2022年10月至2023...目的探讨团体绘画治疗对恢复期精神分裂症住院患者阴性和阳性症状、社会功能和认知功能的影响,为患者提供非药物治疗方法。方法将2022年1月至9月45例本院住院恢复期精神分裂症患者设为对照组,并予以常规药物及康复训练;2022年10月至2023年6月45例恢复期精神分裂症住院患者设为观察组,在对照组基础上团体绘画治疗干预。干预时间8w。干预前后分别采用阳性与阴性症状量表(positive and negative syndrome scale,PANSS)、住院精神患者社会功能量表(scale of social function in psychosis inpatients,SSPI)、重复性成套神经心理状态测验(repeatable battery for the assessment of neuropsychological status,RBANS)比较两组患者阳性与阴性症状、社会功能和认知功能。结果两组各45例患者完成研究。观察组患者阳性阴性症状量表评分干预前后差值高于对照组;观察组患者SSPI评分干预前后差值高于对照组;观察组RBANS评分干预前后差值高于对照组,差异具有统计学意义(均P<0.001)。结论团体绘画治疗可改善患者临床症状,提高患者认知功能,促进社会功能恢复。展开更多
基金supported by the National Natural Science Foundation of China under Grant No.40505011.
文摘A mei-yu front process in the lower reaches of the Yangtze River on 23 June 1999 was simulated by using the fifth-generation Pennsylvania State University-NCAR （PSU/NCAR） Mesoscale Model （MM5） with FDDA （Four Dimension Data Assimilation）. The analysis shows that seven weak small mesoscale vortexes of tens of kilometers, correspondent to surface low trough or mesoscale centers, in the planetary boundary layer （PBL） in the mei-yu front were heavily responsible for the heavy rainfall. Sometimes, several weak small-scale vortexes in the PBL could form a vortex group, some of which would weaken locally, and some would develop to be a meso-α-scale low vortex through combination. The initial dynamical triggering mechanism was related to two strong currents： one was the northeast flow in the PBL at the rear of the mei-yu front, the vortexes occurred exactly at the side of the northeast flow; and the other was the strong southwest low-level jet （LLJ） in front of the Mei-yu front, which moved to the upper of the vortexes. Consequently, there were notable horizontal and vertical wind shears to form positive vorticity in the center of the southwest LLJ. The development of mesoscale convergence in the PBL and divergence above, as well as the vertical positive vorticity column, were related to the small wind column above the nose-shaped velocity contours of the northeast flow embedding southwestward in the PBL, which intensified the horizontal wind shear and the positive vorticity column above the vortexes, baroclinicity and instability.
基金supported by the National Natural Science Foundation of China (10872192)
文摘With the two-scale expansion technique proposed by Yoshizawa,the turbulent fluctuating field is expanded around the isotropic field.At a low-order two-scale expansion,applying the mode coupling approximation in the Yakhot-Orszag renormalization group method to analyze the fluctuating field,the Reynolds-average terms in the Reynolds stress transport equation,such as the convective term,the pressure-gradient-velocity correlation term and the dissipation term,are modeled.Two numerical examples：turbulent flow past a backward-facing step and the fully developed flow in a rotating channel,are presented for testing the efficiency of the proposed second-order model.For these two numerical examples,the proposed model performs as well as the Gibson-Launder （GL） model,giving better prediction than the standard k-ε model,especially in the abilities to calculate the secondary flow in the backward-facing step flow and to capture the asymmetric turbulent structure caused by frame rotation.
文摘目的探讨团体绘画治疗对恢复期精神分裂症住院患者阴性和阳性症状、社会功能和认知功能的影响,为患者提供非药物治疗方法。方法将2022年1月至9月45例本院住院恢复期精神分裂症患者设为对照组,并予以常规药物及康复训练;2022年10月至2023年6月45例恢复期精神分裂症住院患者设为观察组,在对照组基础上团体绘画治疗干预。干预时间8w。干预前后分别采用阳性与阴性症状量表(positive and negative syndrome scale,PANSS)、住院精神患者社会功能量表(scale of social function in psychosis inpatients,SSPI)、重复性成套神经心理状态测验(repeatable battery for the assessment of neuropsychological status,RBANS)比较两组患者阳性与阴性症状、社会功能和认知功能。结果两组各45例患者完成研究。观察组患者阳性阴性症状量表评分干预前后差值高于对照组;观察组患者SSPI评分干预前后差值高于对照组;观察组RBANS评分干预前后差值高于对照组,差异具有统计学意义(均P<0.001)。结论团体绘画治疗可改善患者临床症状,提高患者认知功能,促进社会功能恢复。
