为提升高速公路通行效率,优化网联自动驾驶车辆(connected and autonomous vehicle,CAV)专用道设置条件下的交织区时空资源配置,以保证CAV高效安全汇入主线专用道,提出了一种基于深度强化学习的交织区集成控制策略。以主线三车道高速公...为提升高速公路通行效率,优化网联自动驾驶车辆(connected and autonomous vehicle,CAV)专用道设置条件下的交织区时空资源配置,以保证CAV高效安全汇入主线专用道,提出了一种基于深度强化学习的交织区集成控制策略。以主线三车道高速公路为研究对象,并设置内侧车道为CAV专用道,设计了充分考虑CAV专用道汇入需求同时兼顾主线通行效率和匝道排队长度的多目标奖励函数,利用深度确定性策略梯度(deep deterministic policy gradient,DDPG)算法实现包括入口匝道信号控制、主线车道级可变限速以及CAV车队间隙调整的集成控制策略,最后使用SUMO和Python搭建高速公路交织区仿真场景,验证所提集成控制策略的有效性。研究结果表明:CAV渗透率为30%时,在低、中、高不同水平交通需求场景下,对比无控制情况集成控制策略可使CAV汇入专用道的纵向位置有所提前,CAV汇入专用道成功率分别增加了19.34%、22.86%、25.55%;此外,车辆平均行程时间也分别降低了5.42%、17.41%、20.65%。所提出的交织区集成控制策略效果显著,不仅实现了CAV汇入专用道的有效引导,还提升了主线的通行效率及运行安全,为改善CAV专用道设置条件下高速公路交织区交通运行状况提供了理论依据和技术参考。展开更多
The inhibitory effect of the second phase on dislocation movement has long been deemed as a great con-tribution to the strengthening of alloys.We investigate the electronic behavior at theα-Al matrix/second phase int...The inhibitory effect of the second phase on dislocation movement has long been deemed as a great con-tribution to the strengthening of alloys.We investigate the electronic behavior at theα-Al matrix/second phase interface to explore its inhibitory effect on dislocation movement.This work focuses on the dif-ficulty in dislocation movement on the interface ofα-Al/Al_(3)Sc,α-Al/θ’(Al_(2)Cu),andα-Al/T_(1)(Al_(2)CuLi)of aluminum-lithium-scandium alloy based on detailed transmission electron microscopy investigation and electron transport calculation.The more drastic the electron transport between two atoms at the inter-face,the more intense the interaction between them,corresponding to the larger difficulty in breaking and forming bonds between them during the movement process of the extra half plane of dislocation on the interface.The calculated difference in density of valence electrons and differential charge density atα-Al/second phase interface reveals that Al_(3)Sc is characterized by the largest resistance to dislocation movement compared toθ’(Al_(2)Cu)and T_(1)(Al_(2)CuLi).The large differential charge density between the in-terface of(100)Al_(3)Sc/(100)Al demonstrates the strong bonds betweenα-Al and Al_(3)Sc and the large difficulty for the extra half plane of dislocation to form or break bonds during the movement process atα-Al/Al_(3)Sc interface.The dislocation pile-up indicates a discernible hindering effect of theα-Al/Al_(3)Sc interface on dislocation movement.The hindering effect presented byα-Al/Al_(3)Sc interface is favorable for the tensile strength.展开更多
文摘目的研究谷氨酰胺果糖-6-磷酸转氨酶2(glutamine fructose-6-phosphate transaminase 2,GFPT2)对前列腺癌细胞迁移的影响及其潜在的分子机制。方法采用qRT-PCR检测RWPE-1细胞及五种人前列腺癌细胞系中GFPT2基因mRNA的表达水平;分析人类蛋白质图谱(The Human Protein Atlas,HPA)中前列腺正常组织和癌组织的GFPT2免疫组化数据;利用siRNA构建GFPT2基因干扰的细胞模型;利用Transwell实验和细胞划痕实验评估细胞迁移能力;通过Western blot检测细胞上皮-间充质转化(epithelial-mesenchymal transition,EMT)相关生物标志物的变化。结果与RWPE-1细胞相比,高转移潜能的前列腺癌细胞系PC3和DU145中GFPT2 mRNA的表达水平显著升高。HPA数据库GFPT2免疫组化数据表明,前列腺癌组织中GFPT2的蛋白水平明显高于正常前列腺组织。干扰GFPT2明显降低了前列腺癌细胞的O-GlcNAc糖基化水平。体外实验表明,干扰GFPT2显著抑制了前列腺癌细胞的迁移能力,并导致EMT相关蛋白E-cadherin的水平上调,N-cadherin和Vimentin的水平下调。结论GFPT2在前列腺癌中表达升高并促进肿瘤细胞迁移,有望成为抑制前列腺癌转移的新靶点。
基金This work was financially supported by the National Natural Science Foundation of China(No.51774106).
文摘The inhibitory effect of the second phase on dislocation movement has long been deemed as a great con-tribution to the strengthening of alloys.We investigate the electronic behavior at theα-Al matrix/second phase interface to explore its inhibitory effect on dislocation movement.This work focuses on the dif-ficulty in dislocation movement on the interface ofα-Al/Al_(3)Sc,α-Al/θ’(Al_(2)Cu),andα-Al/T_(1)(Al_(2)CuLi)of aluminum-lithium-scandium alloy based on detailed transmission electron microscopy investigation and electron transport calculation.The more drastic the electron transport between two atoms at the inter-face,the more intense the interaction between them,corresponding to the larger difficulty in breaking and forming bonds between them during the movement process of the extra half plane of dislocation on the interface.The calculated difference in density of valence electrons and differential charge density atα-Al/second phase interface reveals that Al_(3)Sc is characterized by the largest resistance to dislocation movement compared toθ’(Al_(2)Cu)and T_(1)(Al_(2)CuLi).The large differential charge density between the in-terface of(100)Al_(3)Sc/(100)Al demonstrates the strong bonds betweenα-Al and Al_(3)Sc and the large difficulty for the extra half plane of dislocation to form or break bonds during the movement process atα-Al/Al_(3)Sc interface.The dislocation pile-up indicates a discernible hindering effect of theα-Al/Al_(3)Sc interface on dislocation movement.The hindering effect presented byα-Al/Al_(3)Sc interface is favorable for the tensile strength.
