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土木工程设计公式智能发现方法

建筑结构学报 2024年第7期45卷 80-88页

作者：陈培尧王琛丁然樊健生清华大学土木工程系北京100084

土木工程智能计算技术具有高准确性和高效性,但由于黑盒性质,其结果难以被研究者与工程师理解,阻碍了其在以安全性为首要原则的实际工程中的推广应用。为此,提出一种基于量纲分析与工程先验知识的设计公式智能发现方法,通过智能计算技... 详细信息

土木工程智能计算技术具有高准确性和高效性,但由于黑盒性质,其结果难以被研究者与工程师理解,阻碍了其在以安全性为首要原则的实际工程中的推广应用。为此,提出一种基于量纲分析与工程先验知识的设计公式智能发现方法,通过智能计算技术自动从试验数据中识别出影响材料与构件性能的关键特征,并智能生成量纲平衡、物理含义清晰、力学可解释性高的设计计算公式。基于符号回归表达式树建立了考虑量纲约束的公式智能生成模型,能够保证公式的力学合理性;研发了针对多力学-几何变量场景的归一化方法与基于谱聚类和决策树的工程特征分段算法,进一步提高了模型的稳定性和准确性。以配筋水泥基材料连梁的受剪承载力为例验证该方法的有效性,结果表明:智能生成的公式相较于人工经验公式计算结果准确性提高61.3%,拟合相关性提高23.3%,相关系数达0.90,性能优异;此外,与传统符号回归方法相比,智能生成的公式不仅更为准确,且具有量纲正确性,工程泛化能力更强;同时,有助于揭示力学机理,加速新材料、新结构从试验到设计方法的落地转化流程。

关键词：土木工程设计公式人工智能符号回归力学可解释性

A dynamic managed pressure well-control method for rapid treatment of gas kick in deepwater managed pressure drilling

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Petroleum Science 2022年第5期19卷 2297-2313页

作者： Hong-Wei Yang Jun Li Ji-Wei Jiang Hui Zhang Bo-Yun Guo Geng Zhang wang chen China University of Petroleum-Beijing Beijing102249China China University of Petroleum-Beijing at Karamay Karamay834000XinjiangChina CNPC Engineering Technology R&D Company Limited Beijing102206China University of Louisiana at Lafayette LafayetteLA70504USA

During deepwater managed pressure drilling(MPD),the gas kick may occur in abnormally high-pressure formations.If the traditional well control method is adopted,the treatment time is long and the advantage of early gas kick detection of MPD is lost.The dynamic managed pressure well-control(MPWC)method can be used to rapidly treat gas kick in deepwater MPD.In this paper,considering the effect of large-variable-diameter annulus and complex wellbore temperature in deepwater drilling,a simplified model of non-isothermal gas-liquid two-phase flow was established for dynamic deepwater MPWC simulation.Using this model,the response characteristics of outlet flow and wellhead backpressure were investigated.The results indicated that the gas fraction,outlet liquid flow rate,pit gain and wellhead backpressure presented complex alternating characteristics when gas moved upwards in the wellbore due to the large-variable-diameter annulus.The outlet liquid flow rate would be lower than the inlet flow rate and the pit gain would decrease before the gas moved to the wellhead.The variation trend of the wellhead backpressure was consistent with that of the pit gain.When the gas-liquid mixture passed through the choke,the expansion or compression of the gas caused part of the choke pressure drop to be supplemented or unloaded,delaying the response rate of the wellhead backpressure.The wellbore temperature,borehole diameter and seawater depth had different effects on outlet flow rate,pit gain and wellhead backpressure.This research could provide a new idea for well control methods in deepwater managed pressure drilling.

关键词： Gas kick Managed pressure well-control Gas-liquid two-phase flow Wellhead backpressure Outlet flow characteristics Deepwater managed pressure drilling

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基于二级时空分桶的伴随轨迹查询

计算机学报 2024年第1期47卷 131-147页

作者：王晨旭汪谨权杨鑫西安交通大学软件学院西安710049 西安交通大学智能网络与网络安全教育部重点实验室西安710049

随着移动传感器设备的普及,人们能够采集到的位置数据越来越多,轨迹数据的规模也越来越庞大.从大规模时空数据中查找与指定轨迹最相似的前k条轨迹一直是时空大数据挖掘的重要挑战之一.现有的相似轨迹查询方法大都包括三个阶段:(1)对海... 详细信息

随着移动传感器设备的普及,人们能够采集到的位置数据越来越多,轨迹数据的规模也越来越庞大.从大规模时空数据中查找与指定轨迹最相似的前k条轨迹一直是时空大数据挖掘的重要挑战之一.现有的相似轨迹查询方法大都包括三个阶段:(1)对海量的离线轨迹数据建立索引;(2)基于索引结构从已知轨迹集中查询与指定轨迹相似的候选轨迹;(3)计算指定轨迹与候选轨迹之间的精确相似度并返回相似度最大的前k条轨迹.但大多数现有方法对轨迹进行聚类索引时不能有效利用时间和空间信息,导致时间相似度不高的轨迹也会被划分到相同的索引项上,最终影响查询的准确性和效率.此外,现有的时空轨迹相似度计算方法存在大量的无效运算,使得相似轨迹的查询效率整体较低.针对当前伴随轨迹查询方法对时间与空间信息利用不充分的问题,本文提出一种新的二级时空分桶索引结构,首先将每条轨迹数据按照时间滑动窗口划分为若干带有时间槽信息的子轨迹,在时间上对轨迹进行一级索引聚类;在此基础上对在相同时间槽内的子轨迹进行二级空间索引聚类,利用哈希算法将具有连续相同位置点的子轨迹映射到同一时空分桶中.与已有索引方法相比,该方法对不同轨迹在索引时具有更好的区分度,查询时的筛选条件更为严格,有效降低了候选轨迹集的规模.针对现有轨迹相似度计算方法效率低下的问题,提出一种基于时差约束的轨迹相似度计算方法.利用轨迹之间的时差排除大量不必要的位置比较运算,将轨迹相似度的计算复杂度控制在线性级别,大大提高了计算效率,同时为过滤伴随轨迹查询过程中的无效计算,对基于时差约束的轨迹相似度计算方法进行变体得到一种上下界过滤方法,最大限度地避免了无效计算.最后,在4个真实的大规模轨迹数据集上对所提方法进行实验验证,实验结果表明所提方法的轨迹查找效率是已知最好方法的9~20倍,证明了算法的有效性.

关键词：二级时空索引轨迹相似度计算伴随轨迹查询

Switching on/off phosphorescent or non-radiative channels by aggregation-induced quantum interference

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Aggregate

Aggregate 2024年第1期5卷 175-184页

作者： Yi Kong Yu-chen wang Xunkun Huang WanZhen Liang Yi Zhao Department of Chemistry State Key Laboratory of Physical Chemistry of Solid SurfacesiChEMFujian Provincial Key Laboratory of Theoretical and Computational Chemistryand College of Chemistry and Chemical EngineeringXiamen UniversityXiamenPeople’s Republic of China

Pure organic materials with persistent and efficient room-temperature phosphorescence have recently aroused great research interest due to their vast potential in applications.One crucial design principle for such materials is to suppress as much as possible the non-radiative decay of the triplet exciton while maintaining a moderate phosphorescent radiative rate.However,molecular engineering often exhibits similar regulation trends for the two processes.Here,we propose that the quantum interference caused by aggregation can be utilized to control the phosphorescent and non-radiative decay channels.We systematically analyze various constructive and destructive transition pathways in aggregates with different molecular packing types and establish clear relationships between the luminescence characters and the signs of the singlet and triplet excitonic couplings.It is shown that the decay channels can be flexibly switched on or off by regulating the packing type and excitonic couplings.Most importantly,an enhanced phosphorescent decay and a completely suppressed non-radiative decay can be simultaneously realized in the aggregate packed with inversion symmetry.This work lays the theoretical foundation for future experimental realization of quantum interference effects in phosphorescence.

关键词： excitonic coupling intersystem crossing organic aggregates organic room temperature phosphorescence quantum interference

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基于目标特征的数据压缩预处理方法

声学技术 2024年第1期43卷 113-118页

作者：王晨陈晶晶中国科学院声学研究所东海研究站上海201815

随着水下自动监测技术的不断发展,对于数据的实时传输效率和测量精度的要求也越来越高,而高质量无损数据压缩传输技术还存在严重不足。文章利用在广西西江航道上建立的侧扫声呐船舶吃水自动监测系统,提出了一种基于目标特征的数据压缩... 详细信息

随着水下自动监测技术的不断发展,对于数据的实时传输效率和测量精度的要求也越来越高,而高质量无损数据压缩传输技术还存在严重不足。文章利用在广西西江航道上建立的侧扫声呐船舶吃水自动监测系统,提出了一种基于目标特征的数据压缩预处理方法。该方法根据散货船的船体结构和声图成像特点,在进行数据压缩前分别在时间和空间两个维度上实现对目标信号的识别和提取,完成对无关冗余数据的剔除。该预处理方法不仅可以大幅提高数据压缩的压缩比,提高传输效率,节省存储空间,还可以保证用于测量计算的目标关键特征信息不丢失,为进一步突破无损数据压缩的压缩比限制提供新思路。

关键词：目标特征数据压缩水下测量侧扫声呐船舶监测

Application of non-invasive ventilation in China over 20 years

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Chinese Medical Journal 2014年第24期127卷 4278-4282页

作者： wang chen Zhang Xilong China-Japan Friendship Hospital Beijing 100029 China Department of Respirology Medicine First Affiliated Hospital of Nanjing Medical University Nanjing Jiangsu 210029 China

Over the last 20 years, the application of non-invasive ventilation （NIV） in China has progressively increased both in the hospital and extrahospital setting. The history of the NIV and its increasing spread in the clinical practice over China are one of the most important results of the cooperation between medicine and non-invasive mechanic technology.

关键词： non-invasive ventilation China

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汕头市礐石花岗岩地貌特征及其成因

热带地理 2024年第3期44卷 403-414页

作者：邱明昆王为温小浩陈敏王晨冯静华南师范大学地理科学学院广州510623 西藏大学生态环境学院拉萨850000 深圳职业技术学院建筑工程学院广东深圳518055

以广东汕头礐石地区景区内各类花岗岩地貌为研究对象,利用地表调查和洞穴调查,在国内外已有研究的基础上,对礐石地区花岗岩的地貌特征、成因及形成年代进行探讨。结果表明:礐石山由燕山晚期花岗岩构成,于中更新世晚期之前就受风化作用;... 详细信息

以广东汕头礐石地区景区内各类花岗岩地貌为研究对象,利用地表调查和洞穴调查,在国内外已有研究的基础上,对礐石地区花岗岩的地貌特征、成因及形成年代进行探讨。结果表明:礐石山由燕山晚期花岗岩构成,于中更新世晚期之前就受风化作用;礐石花岗岩石节理的性质和礐石地区高温多雨的热带季风气候下产生的风化作用,是形成礐石花岗岩地貌的基本因素;礐石地区花岗岩山体主要分为石蛋山、峰林山、馒头山3种类型;洞穴可划分石核洞,崩塌洞穴,裂隙洞和龛4类。

关键词：花岗岩地貌控制因素形成年代石蛋山礐石汕头

Advanced nanomedicines and immunotherapeutics to treat respiratory diseases especially COVID-19 induced thrombosis

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World Journal of Clinical Cases 2024年第16期12卷 2704-2712页

作者： Jie Wu Ying Zheng Li-Na Zhang Cai-Li Gu wang-Li chen Min-Qiang Chang Department of Respiratory and Oncology 72nd Group Army Hospital of PLAHuzhou 313000Zhejiang ProvinceChina Department of Otorhinolaryngology 72^(nd)Group Army Hospital of PLAHuzhou 313000Zhejiang ProvinceChina

Immunotherapy and associated immune regulation strategies gained huge attraction in order to be utilized for treatment and prevention of respiratory diseases.Engineering specifically nanomedicines can be used to regulate host immunity in lungs in the case of respiratory diseases including coronavirus disease 2019(COVID-19)infection.COVID-19 causes pulmonary embolisms,thus new therapeutic options are required to target thrombosis,as conventional treatment options are either not effective due to the complexity of the immunethrombosis pathophysiology.In this review,we discuss regulation of immune response in respiratory diseases especially COVID-19.We further discuss thrombosis and provide an overview of some antithrombotic nanoparticles,which can be used to develop nanomedicine against thrombo-inflammation induced by COVID-19 and other respiratory infectious diseases.We also elaborate the importance of immunomodulatory nanomedicines that can block pro-inflammatory signalling pathways,and thus can be recommended to treat respiratory infectious diseases.

关键词： Nanomedicines Immunotherapeutics Respiratory diseases COVID-19 Thrombosis

Early use of non-invasive positive pressure ventilation for acute exacerbations of chronic obstructive pulmonary disease:a multicentre randomized controlled trial

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Chinese Medical Journal 2005年第24期118卷 2034-2040页

作者： wang chen Beijing Institute of Respiratory Medicine Beijing Chaoyang Hospital Capital University of Medical Sciences Beijing 100020 China

Background Respiratory muscle fatigue plays an important role in acute exacerbations of chronic obstructivepulmonary disease (AECOPD)·In previous clinical studies, non-invasive positive pressure ventilation (NPPV)was proved to be successful only for AECOPD patients with severe respiratory failure·We hypothesized that, theoutcomes of AECOPD would be improved if NPPVis early (within 24 to 48 hours of admission) administered inthose patients with respiratory muscle fatigue and mild respiratory insufficiency, especially in patients withoutfulfilling the conventional criteria of mechanical ventilatory support·Methods Aprospective multicentre randomized controlled trial was conducted in19 hospitals in China over16months·Three hundred and forty-two AECOPD patients with pH≥7·25 and PaCO2>45 mmHg were recruitedon general ward and randomly assigned to standard medical treatment (control group) or early administration ofadditional NPPV (NPPV group)·Results The characteristics of two groups on admission were similar·The number of AECOPD patientsrequiring intubations in NPPV group was much fewer than that of the control group (8/171 vs 26/71,P=0·002)·Subgroup analysis showed the needs for intubation in mildly (pH≥7·35) and severe (pH<7·30)acidotic patients in NPPVgroup were both decreased (9/80 vs2/71,P=0·047 and 8/30 vs3/43,P=0·048,respectively)·The mortality in hospital was reduced slightly by NPPV but with no significant difference (7/171vs 12/171,P=0·345)·Respiratory rate (RR),scale for accessory muscle use and arterial pHimproved rapidlyat the first 2 hours only in patients of NPPV group·After 24 hours, the differences of pH, PaO2, scale foraccessory muscle use and RR in NPPV group [(7·36±0·06) mmHg, (72±22) mmHg, (2·5±0·9) /min,(22±4) /min] were statistically significant compared with control group (7·37±0·05) mmHg, (85±34)mmHg, (2·3±1·1) /min, (21±4) /min,P<0·01 for all comparisons]·Conclusions The early use of NPPV on general ward improves arterial blood gas and respiratory pattern,decreases the rate of need for intub

关键词：正电压慢性阻塞性肺疾病随机实验临床表现病理机制