针对智能网联环境下传感器感知和车车通信(vehicle to vehicle,V2V)都存在时延的问题,提出一种考虑双时延和多前车反馈(dual delay multiple look-ahead full velocity difference,DD-MLFVD)的智能网联汽车跟驰模型.根据智能网联汽车感...针对智能网联环境下传感器感知和车车通信(vehicle to vehicle,V2V)都存在时延的问题,提出一种考虑双时延和多前车反馈(dual delay multiple look-ahead full velocity difference,DD-MLFVD)的智能网联汽车跟驰模型.根据智能网联汽车感知特性引入双时延信息,结合多前车速度差和期望速度信息提出DD-MLFVD模型.通过微小扰动法求解DD-MLFVD模型的临界稳定性条件,同时结合模型参数研究前车数量和时延大小对模型稳定域的影响.利用直道场景对模型进行仿真分析,着重研究变扰动和变时延场景下DD-MLFVD对交通流的稳定效果.结果表明:面对复杂扰动影响,DD-MLFVD模型能够较好吸收扰动,可提升交通流的稳定性.展开更多
Optical neural networks have significant advantages in terms of power consumption,parallelism,and high computing speed,which has intrigued extensive attention in both academic and engineering communities.It has been c...Optical neural networks have significant advantages in terms of power consumption,parallelism,and high computing speed,which has intrigued extensive attention in both academic and engineering communities.It has been considered as one of the powerful tools in promoting the fields of imaging processing and object recognition.However,the existing optical system architecture cannot be reconstructed to the realization of multi-functional artificial intelligence systems simultaneously.To push the development of this issue,we propose the pluggable diffractive neural networks(P-DNN),a general paradigm resorting to the cascaded metasurfaces,which can be applied to recognize various tasks by switching internal plug-ins.As the proof-of-principle,the recognition functions of six types of handwritten digits and six types of fashions are numerical simulated and experimental demonstrated at near-infrared regimes.Encouragingly,the proposed paradigm not only improves the flexibility of the optical neural networks but paves the new route for achieving high-speed,low-power and versatile artificial intelligence systems.展开更多
Objective:To summarize the characteristics and evaluate the quality of the methodology and evidence within systematic reviews(SRs)of Chinese herbal medicine(CHM)for Mycoplasma pneumoniae pneumonia(MPP)inchildren.Metho...Objective:To summarize the characteristics and evaluate the quality of the methodology and evidence within systematic reviews(SRs)of Chinese herbal medicine(CHM)for Mycoplasma pneumoniae pneumonia(MPP)inchildren.Methods:SRs of randomized controlled trials were searched using PubMed,the Cochrane Library,Embase,the Chinese National Knowledge Infrastructure Databases(CNKI),the Chinese Scientific Journals Database(VIP),Wanfang,and the SinoMed Database.SRs on the use of CHM alone or in combination with Western medications for MPP in children were included.The study compared the effects of Western medicine alone with those of CHM.The evidence quality using the A Measurement Tool to Assess Systematic Reviews(AMSTAR)2,the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)2020,and the Grading of Recommendations,Assessment,Development,and Evaluation(GRADE)criteria.The primary indicators were the total effective rate,fever subsidence time,and cough disappearance time.The secondary outcomes were pulmonary rale disappearance time,average hospitalization time,lung X-ray infiltrate disappearance time,immunological indices,and inflammatory cytokine levels.Results:Twelve relevant SRs were included;75%(9/12)were assessed as very low quality,and 25%(3/12)Were rated as low quality using the AMSTAR 2 criteria.According to the PRISMA 2020 checklist,the average SR score was 20.3 out of a 27 point maximum.In all SRs,CHM demonstrated improvement in symptoms and signs among children with MPP.The evidence quality using the GRADE criteria ranged from"very low"(>50%)to"moderate"(<5%).The most common downgrading factor was imprecision,followed by publication bias and inconsistency.Conclusion:This overview highlights the limited quality of the methodology and evidence of the included SRs.Although the included studies showed the beneficial effects of CHM on MPP in children,it was difficult to draw firm conclusions owing to methodological flaws.展开更多
儿茶素和茶黄素作为红茶的主要活性成分对红茶的色、香、味等品质呈现起到重要作用,也是评价红茶品质优劣的重要指标。该研究基于高效液相色谱技术,开发了可同时、快速、准确检测红茶中儿茶素和茶黄素的分析方法。以A相0.1%甲酸-乙腈、B...儿茶素和茶黄素作为红茶的主要活性成分对红茶的色、香、味等品质呈现起到重要作用,也是评价红茶品质优劣的重要指标。该研究基于高效液相色谱技术,开发了可同时、快速、准确检测红茶中儿茶素和茶黄素的分析方法。以A相0.1%甲酸-乙腈、B相0.1%甲酸-水为流动相,进样量20μL,经安捷伦SB-C;色谱柱(4.6 mm×250 mm, 5μm)分离,在柱温30℃、流速1 mL/min、时间50 min的条件下进行检测,使用外标法定量检测样品含量。结果显示,该方法具有较高的灵敏度(LOD:0.21~11.13μg/mL),质量浓度范围内与其峰面积的线性关系良好(R^(2)≥0.999 0),精密度、重复性和稳定性试验的相对标准偏差(relative standard deviation, RSD)均<5%(n=6),加标平均回收率为98.69%~104.77%,RSD均<3.31%(n=6)。该方法简便、高效、准确,可用于茶叶中儿茶素和茶黄素的定性定量测定。展开更多
文摘针对智能网联环境下传感器感知和车车通信(vehicle to vehicle,V2V)都存在时延的问题,提出一种考虑双时延和多前车反馈(dual delay multiple look-ahead full velocity difference,DD-MLFVD)的智能网联汽车跟驰模型.根据智能网联汽车感知特性引入双时延信息,结合多前车速度差和期望速度信息提出DD-MLFVD模型.通过微小扰动法求解DD-MLFVD模型的临界稳定性条件,同时结合模型参数研究前车数量和时延大小对模型稳定域的影响.利用直道场景对模型进行仿真分析,着重研究变扰动和变时延场景下DD-MLFVD对交通流的稳定效果.结果表明:面对复杂扰动影响,DD-MLFVD模型能够较好吸收扰动,可提升交通流的稳定性.
基金The authors acknowledge the funding provided by the National Key R&D Program of China(2021YFA1401200)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910007022)+2 种基金National Natural Science Foundation of China(No.U21A20140,No.92050117,No.62005017)programBeijing Municipal Science&Technology Commission,Administrative Commission of Zhongguancun Science Park(No.Z211100004821009)This work was supported by the Synergetic Extreme Condition User Facility(SECUF).
文摘Optical neural networks have significant advantages in terms of power consumption,parallelism,and high computing speed,which has intrigued extensive attention in both academic and engineering communities.It has been considered as one of the powerful tools in promoting the fields of imaging processing and object recognition.However,the existing optical system architecture cannot be reconstructed to the realization of multi-functional artificial intelligence systems simultaneously.To push the development of this issue,we propose the pluggable diffractive neural networks(P-DNN),a general paradigm resorting to the cascaded metasurfaces,which can be applied to recognize various tasks by switching internal plug-ins.As the proof-of-principle,the recognition functions of six types of handwritten digits and six types of fashions are numerical simulated and experimental demonstrated at near-infrared regimes.Encouragingly,the proposed paradigm not only improves the flexibility of the optical neural networks but paves the new route for achieving high-speed,low-power and versatile artificial intelligence systems.
基金supported by the Evidence-based Capacity Building Project of Traditional Chinese medicine of the National Administration of Traditional Chinese Medicine(60102)the Fundamental Research Funds for the Central Public Welfare Research Institutes(49425).
文摘Objective:To summarize the characteristics and evaluate the quality of the methodology and evidence within systematic reviews(SRs)of Chinese herbal medicine(CHM)for Mycoplasma pneumoniae pneumonia(MPP)inchildren.Methods:SRs of randomized controlled trials were searched using PubMed,the Cochrane Library,Embase,the Chinese National Knowledge Infrastructure Databases(CNKI),the Chinese Scientific Journals Database(VIP),Wanfang,and the SinoMed Database.SRs on the use of CHM alone or in combination with Western medications for MPP in children were included.The study compared the effects of Western medicine alone with those of CHM.The evidence quality using the A Measurement Tool to Assess Systematic Reviews(AMSTAR)2,the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)2020,and the Grading of Recommendations,Assessment,Development,and Evaluation(GRADE)criteria.The primary indicators were the total effective rate,fever subsidence time,and cough disappearance time.The secondary outcomes were pulmonary rale disappearance time,average hospitalization time,lung X-ray infiltrate disappearance time,immunological indices,and inflammatory cytokine levels.Results:Twelve relevant SRs were included;75%(9/12)were assessed as very low quality,and 25%(3/12)Were rated as low quality using the AMSTAR 2 criteria.According to the PRISMA 2020 checklist,the average SR score was 20.3 out of a 27 point maximum.In all SRs,CHM demonstrated improvement in symptoms and signs among children with MPP.The evidence quality using the GRADE criteria ranged from"very low"(>50%)to"moderate"(<5%).The most common downgrading factor was imprecision,followed by publication bias and inconsistency.Conclusion:This overview highlights the limited quality of the methodology and evidence of the included SRs.Although the included studies showed the beneficial effects of CHM on MPP in children,it was difficult to draw firm conclusions owing to methodological flaws.
文摘儿茶素和茶黄素作为红茶的主要活性成分对红茶的色、香、味等品质呈现起到重要作用,也是评价红茶品质优劣的重要指标。该研究基于高效液相色谱技术,开发了可同时、快速、准确检测红茶中儿茶素和茶黄素的分析方法。以A相0.1%甲酸-乙腈、B相0.1%甲酸-水为流动相,进样量20μL,经安捷伦SB-C;色谱柱(4.6 mm×250 mm, 5μm)分离,在柱温30℃、流速1 mL/min、时间50 min的条件下进行检测,使用外标法定量检测样品含量。结果显示,该方法具有较高的灵敏度(LOD:0.21~11.13μg/mL),质量浓度范围内与其峰面积的线性关系良好(R^(2)≥0.999 0),精密度、重复性和稳定性试验的相对标准偏差(relative standard deviation, RSD)均<5%(n=6),加标平均回收率为98.69%~104.77%,RSD均<3.31%(n=6)。该方法简便、高效、准确,可用于茶叶中儿茶素和茶黄素的定性定量测定。
