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Anisotropic surface roughness and shear behaviors of rough-walled plaster joints under constant normal load and constant normal stiffness conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第2期12卷 338-352页

作者： Richeng Liu sha lou Xiaojing Li Guansheng Han Yujing Jiang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116China School of Engineering Nagasaki UniversityNagasaki852-8521Japan Department of Hydraulic Engineering Tongji UniversityShanghai200092China School of Civil Engineering Shandong Jianzhu UniversityJinan116024China State Key Laboratory of Mining Disaster Prevention and Control Shandong University of Science and TechnologyQingdao266590China

In this context,we experimentally studied the anisotropic mechanical behaviors of rough-walled plaster joints using a servo-controlled direct shear apparatus under both constant normal load(CNL)and constant normal stiffness(CNS)*** shear-induced variations in the normal displacement,shear stress,normal stress and sheared-off asperity mass are analyzed and correlated with the inclination angle of the critical waviness of joint *** results show that CNS condition gives rise to a smaller normal displacement due to the larger normal stress during shearing,compared with CNL *** CNL conditions,there is one peak shear stress during shearing,whereas there are no peak shear stress for some cases and two peaks for other cases under CNS conditions depending on the geometry of joint *** inclination angle of the critical waviness has been verified to be capable of describing the joint surface roughness and *** joint surface is more significantly damaged under CNS conditions than that under CNL *** increment of the inclination angle of the critical waviness,both the normal displaceme nt and shea red-off asperity mass increase,following power law functions;yet the coefficient of deternination under CNL conditions is larger than that under CNS *** is because the CNS condition significantly decreases the inclination angle of the critical waviness during shearing due to the larger degree of asperity degradation.

关键词： Joint Constant normal load(CNL) Constant normal stiffness(CNS) Shear anisotropy Surface roughness

Hurricane impacts on turbidity and sediment in the Rookery Bay National Estuarine Research Reserve,Florida,USA

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International Journal of Sediment Research 2016年第4期31卷 330-340页

作者： sha lou Wenrui Huang Shuguang Liu Guihui Zhong Elijah Johnson Department of Hydraulic Engineering Key Laboratory of Yangtze Water EnvironmentMinistry of EducationTongji University FAMU-FSU College of Engineering Florida State University NOAA-ECSC School of the EnvironmentFlorida A&M University

The resuspension and transportation of sediments affect the nutrient or contaminants cycles in water ***,hurricane-induced sediment resuspension in coastal waters may cause environment impacts on coastal *** this study,field observed data during a hurricane event from the Rookery Bay National Estuarine Research Reserve(Rookery Bay NERR),Florida,were *** on the relationship between sediment and turbidity,variations of turbidity in the Rookery Bay NERR were discussed in this paper under the impact of the Hurricane Isaac in *** series analysis indicates that Hurricane Isaac causes the substantial increase of *** direct regression analysis with raw data was found to result in poor correlation(R2 0.6) between wind speed and *** improvement was made by introducing a phase factor to account for the lag time between the peak turbidity and peak wind speed,which lead to further improvement of the regression equation between wind speed and *** using Hanning Filter and phase factor,the regression equation between turbidity and wind speed fits well with observations(R2 > 0.96).Different lag time between wind speed and turbidity at different locations illustrated that wind had different effects on turbidity due to the locations and water *** on the approximate empirical relationship between turbidity and sediment concentration,a regression equation between wind speed and sediment concentration was derived *** equation could be applied to approximately estimate the sediment concentration using wind speed during hurricane,especially with the strong wind speed above 4 m/*** can be used to provide technical supports for sediment assessment and coastal zone r

关键词： Hurricane impacts Sediment Turbidity Wind Hanning Filter Phase factor Estuary

Fully integrated modeling of surface water and groundwater in coastal areas

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Journal of Hydrodynamics 2018年第3期30卷 441-452页

作者： sha lou Shu-guang Liu Gangfeng Ma Gui-hui Zhong Bo Li Department of Hydraulic Engineering Tongji University Shanghai 200092 China Key Laboratory of Yangtze River Water Environment Ministry of Education Tongji University Shanghai 200092 China Department of Civil and EnvironmentalEngineering Old Dominion University Norfolk VA USA School of Engineering Nagasaki University Nagasaki Japan

This paper presents an improved model based on a three-dimensional non-hydrostatic wave model NHWAVE to simulate the interactions between the surface water and the groundwater affected by tides or waves in coastal areas. With the model, both the surface water flow and the groundwater flow are calculated based on the well-balanced Volume-averaged Reynolds-averaged Navier-Stokes equations. The spatially varying porosity and hydraulic conductivity are used to identifiy the domains for the surface water and the groundwater. The model is calibrated and validated using a wide range of laboratory measurements reported in the literature, involving the tide propagation through a sandy embankment, the tide-induced groundwater table fluctuation in a sandy beach, and the wave setup in a sloping sandy beach. The interactions between the surface water and the groundwater are analyzed and the influencing factors on the groundwater flow are discussed. The phase lag between the surface water elevation and the groundwater table fluctuation is mainly influenced by the hydraulic conductivity of the porous media. The wave attenuation in the groundwater is proportional to its propagation distance. The computed wave setup elevationin the permeable beach is smaller than in the impermeable beach. It is shown that the fully integrated model is capable of simulating the interactions between the surface water and the groundwater affected by tides or waves in coastal areas. It can be an efficient tool to study the tide and wave dynamics in the permeable sandy beach.

关键词： Non-hydrostatic model surface water and groundwater interactions wave setup porous media

A 3-D DDA damage analysis of brick masonry buildings under the impact of boulders in mountainous areas

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Journal of Mountain Science 2018年第3期15卷 657-671页

作者： LIU Shu-guang LI Zhu-jun ZHANG Hong WU Wei ZHONG Gui-hui lou sha College of Civil Engineering Tongji University Tongji Architectural Design (Group) Co. Ltd.

In mountainous areas, geological disasters carrying large boulders can cause severe damage to the widely used masonry buildings due to the high impact forces. To better understand the damage of brick masonry buildings under the impact of boulders, a "block-joint" model is developed using threedimensional discontinuous deformation analysis(3-D DDA) to simulate the behaviour of the "brick-mortar" structure. The "block-joint" model is used to capture not only the large displacement and deformation of individual bricks but also the large-scale sliding and opening along the mortar between the bricks. The linear elastic constitutive model is applied to account for the non-plastic deformation behaviour of brick materials. Furthermore, the mechanical characteristics of the mortar are represented using the Mohr-Coulomb and Drucker-Prager criteria. To propose safe structural design schemes and effective reinforcement for brick masonry buildings, seven construction techniques are considered, includingdifferent grades of brick and mortar, effective shear areas and reinforced members. The proposed 3-D DDA model is used to analyse the velocity distribution and the key point displacements of the brick masonry building under the impact of boulders. The results show that upgrading the brick and mortar, increasing the wall thickness, making full use of the wall thickness, and adding a circular beam and structural column are very effective approaches for improving the impact resistance of brick masonry buildings.

关键词： Damage analysis Brick masonry building Boulder impact Brick-mortar structure Block-joint model Discontinuous deformation analysis

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一种高效的自然语言理解语法分析算法

科技通报 2013年第12期29卷 91-93页

作者：罗莎北海职业学院电子信息工程系广西北海536000

针对大型应用软件中嵌入脚本语言问题,提出了一种高效的自然语言理解语法分析算法。建立了脚本语言文法的描述规范,并用VC++设计并实现了一种快捷而通用的语法分析器。实例表明,该算法实现的语法分析器快速、高效,完全可以达到工程要求。

关键词：自然语言词法分析语法分析 LL(1)分析法

Treatment with intravenous alteplase in ischaemic stroke patients with onset time between 4.5 and 24 hours(HOPE):protocol for a randomised,controlled,multicentre study

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Stroke & Vascular Neurology 2024年第3期9卷 318-323,I0274-I0282页

作者： Zhongyu Luo Ying Zhou Yaode He Shenqiang Yan Zhicai Chen Xuting Zhang Yi Chen Lu-sha Tong Wansi Zhong Haitao Hu Kemeng Zhang Jiansheng Yang Bruce C V Campbell Min lou Department of Neurology Zhejiang University School of Medicine Second Affiliated HospitalHangzhouZhejiangChina Department of Medicine and Neurology Melbourne Brain Centre at Royal Melbourne HospitalParkvilleVictoriaAustralia

Background While intravenous thrombolysis is recommended for patients who had an acute ischaemic stroke(AIS)within 4.5hours of symptom onset,there are few randomised trials investigating the benefits of thrombolysis beyond this therapeutic *** To determine whether patients who had an AIS selected with the presence of potentially salvageable tissue on CT perfusion at 4.5–24hours after stroke onset(for stroke with unknown onset time,the midpoint of the time last known to be well and symptom recognition time;for wake-up stroke,the midpoint of the time last known to be well or sleep onset and wake up time)will benefit from intravenous *** HOPE is a prospective,multicentre,randomised,open-label blinded endpoint trial with the stage of phase *** treatment allocation employs 1:1 *** treatment arm under investigation is alteplase with standard therapy,the control arm is standard *** imaging criteria include ischaemic core volume≤70mL,penumbra≥10mL and mismatch≥20%.Study outcomes The primary outcome is non-disabled functional outcome(assessed as modified Rankin Scale score of 0–1 at 90 days).Discussion HOPE is the first trial to investigate whether intravenous thrombolysis with alteplase offers benefits in patients who had an AIS presenting within 4.5–24hours,which has the potential to extend time window and expand eligible population for thrombolysis therapy.

关键词： patients intravenous centre

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河口航道双丁坝影响下异重流运动特性

同济大学学报（自然科学版） 2023年第5期51卷 728-737页

作者：黄硕黄文锐刘曙光娄厦沈淇同济大学土木工程学院上海200092 佛罗里达州立大学工程学院塔拉哈西32310 上海河口海岸科学研究中心上海201201

在河口地区,由密度梯度驱动而产生的异重流是影响航道内泥沙输移的重要因素之一。作为航道整治中常见的建筑物,丁坝群可以缓解航道的泥沙淤积问题、提高通航能力。为探究双丁坝对异重流运动特性的影响,运用粒子图像测速系统(PIV)开展了... 详细信息

在河口地区,由密度梯度驱动而产生的异重流是影响航道内泥沙输移的重要因素之一。作为航道整治中常见的建筑物,丁坝群可以缓解航道的泥沙淤积问题、提高通航能力。为探究双丁坝对异重流运动特性的影响,运用粒子图像测速系统(PIV)开展了开闸式异重流实验,研究了在不同束窄系数情况下,航道异重流稳定阶段内的流场及湍流特性,并对比分析了异重流在两个丁坝位置特征断面处的单宽流量及总流量。结果表明,双丁坝改变了航道内的流场,异重流在经过束窄断面后会向第二个丁坝后部区域横向扩散,进而使得流速加大、高度降低;异重流在两个丁坝束窄断面的单宽流量近似相同,且与束窄系数无关;异重流在束窄断面的总流量与断面宽度成正比,在实际工程中可以通过适当调整丁坝长度来控制侵入航道的异重流总量。

关键词：异重流双丁坝粒子图像测速流速场湍流特性流量

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刚性植物对波高衰减和水流结构的影响

水利水电科技进展 2018年第6期38卷 32-37页

作者：陈明刘曙光娄厦李小林同济大学土木工程学院水利工程系上海200092 上海市政工程设计研究总院(集团)有限公司上海200092

为了研究植物的消浪能力及对水流紊流特性的影响,开展室内水槽试验,用木棒模拟刚性植物,分析了5组植物区布置方案和4组波要素条件下的波高衰减和水流结构。结果表明:植物密度对波高衰减具有显著影响;波浪通过植物区时波高衰减的速率逐... 详细信息

为了研究植物的消浪能力及对水流紊流特性的影响,开展室内水槽试验,用木棒模拟刚性植物,分析了5组植物区布置方案和4组波要素条件下的波高衰减和水流结构。结果表明:植物密度对波高衰减具有显著影响;波浪通过植物区时波高衰减的速率逐渐减小;在同等植物特征条件下,短波比长波衰减幅度更大;植物区内的拖曳力系数CD与低科勒冈-卡朋特(Keulegan-Carpenter)数KC之间存在二次函数关系,CD随着KC的增大而减小,且变化速率呈变缓的趋势;波高和植物密度的增大会引起植物区内部紊动能量ETK的增大;完全淹没植物条件下的ETK大于不完全淹没条件下的ETK;在完全淹没植物的影响下,从底面至水面ETK呈先增大后减小的规律,并在植物冠层处达到最大值。

关键词：水槽试验刚性植物波高衰减水流结构拖曳力系数紊动能量

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传说的美学特征

河南理工大学学报（社会科学版） 2010年第3期11卷 332-334页

作者：娄莎莎中国戏曲学院北京100073

传说是民众的语言艺术,是一种流动的文学。它在民众中流传,既是传说的一个根本特征,又是它不断更新、发展的一种独特方式。在传播过程中,它充分发挥民间语言丰富的表现功能和概括能力,"按照美的规律"经过"合理化"加工、修改和补充,创造... 详细信息

传说是民众的语言艺术,是一种流动的文学。它在民众中流传,既是传说的一个根本特征,又是它不断更新、发展的一种独特方式。在传播过程中,它充分发挥民间语言丰富的表现功能和概括能力,"按照美的规律"经过"合理化"加工、修改和补充,创造出瑰丽多姿的想象世界和艺术形象,以反映民众对生活的理性认识和审美趣味。生动活泼的语言形式和传承机制,使得它在形式、内容和功能等方面天然地富有鲜活的自然美特性。

关键词：传说美学特征审美