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Effects of shore-normal coastal structure on medium-to long-term embayed shoreline evolution

Acta Oceanologica Sinica 2024年第2期43卷 58-66页

作者： jitao yu yuanting Ding Pei Liu Renfu Fan Lin Zhang Hainan Academy of Ocean and Fisheries Sciences Haikou 571126China Yazhou Bay Innovation Institute Hainan Tropical Ocean UniversitySanya 572025China School of Geography and Environmental Sciences Hainan Normal UniversityHaikou 571158China

Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall(M–K)trend test,this study analyzes the linear characteristics and nonlinear behavior of the medium-to long-term shoreline evolution of Jinghai Bay,eastern Guangdong Province.In particular,shoreline rotation caused by a shore-normal coastal structure is emphasized.The results show that the overall shoreline evolution over the past 30 years is characterized by erosion on the southwest beach,with an average erosion rate of 3.1 m/a,and significant accretion on the northeast beach,with an average accretion rate of 5.6 m/a.Results of the M–K trend test indicate that significant shoreline changes occurred in early 2006,which can be attributed to shore-normal engineering.Prior to that engineering construction,the shorelines are slightly eroded,where the average erosion rate is 0.7 m/a.However,after shore-normal engineering is performed,the shoreline is characterized by significant erosion(3.2 m/a)on the southwest beach and significant accretion(8.5 m/a)on the northeast beach,thus indicating that the shore-normal engineering at the updrift headland contributes to clockwise shoreline rotation.Further analysis shows that the clockwise shoreline rotation is promoted not only by longshore sediment transport processes from southwest to northeast,but also by cross-shore sediment transport processes.These findings are crucial for beach erosion risk management,coastal disaster zoning,regional sediment budget assessments,and further observations and predictions of beach morphodynamics.

关键词： shoreline rotation non-linear behavior longshore sediment transport cross-shore sediment transport embayed beach coastal structure

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Erosion hotspot identified along the sandy coast of Shanwei: characteristics and origin

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Acta Oceanologica Sinica 2023年第7期42卷 91-102页

作者： jitao yu yuanting Ding Lin Zhang Pei Liu Renfu Fan Hainan Academy of Ocean and Fisheries Sciences Haikou 571126China Yazhou Bay Innovation Institute Hainan Tropical Ocean UniversitySanya 572025China School of Geography and Environmental Sciences Hainan Normal UniversityHaikou 571158China

Based on the measured beach profile data of Sanzhou Bay from 2015 to 2019,an erosion hotspot was identified along the Shanwei coastline of eastern Guangdong,where the maximum retreat distance of the shoreline exceeded 80 m and the erosion rate was more than 20 m/a.To determine the time at which the erosion hotspot started and the potential causes of its formation,this study used 63 Landsat satellite images from 1986 to 2019 to construct a time series of shoreline positions over the past 30 years by extracting their high-tide shorelines.Next,the M-K trend test method was introduced to evaluate the non-linear shoreline behavior based on the single-transect method.The results showed that the time of approximately 2013 marked the start of the erosion hotspot,the erosion hotspot was characterized by erosion rates of more than 2 m/a(a maximum rate of 31.6 m/a),and the affected shoreline more than 4.3 km from 2013 to 2019.Furthermore,this erosion hotspot was proved to be caused by artificial sand mining in the nearshore zone,which destroyed the original beach’s morphodynamic equilibrium.With the aid of storm events,soil cliffs composed of loose sediment on the backshore were sacrificed to achieve a new equilibrium,resulting in an extremely significant retreat parallel to the coast on the west side of the study area,which reflects the combined effect of human and natural processes.This study provides a concrete example of the rapid response of shorelines to artificial sand mining activities,and the associated finding is a stark warning about the cautious development and utilization of coastal zones and the strict regulation of human activities.

关键词： erosion hotspot shoreline non-linear behavior artificial sand mining beach morphodynamic equilibrium Landsat images

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顺向正弦来流条件下圆柱气动力和绕流流场数值模拟研究

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振动与冲击 2024年第6期43卷 216-224页

作者：于春放靖洪淼王仰雪张记涛邵林媛刘庆宽石家庄铁道大学土木工程学院石家庄050043 石家庄铁道大学省部共建交通工程结构力学行为与系统安全国家重点实验室石家庄050043 河北省风工程和风能利用工程技术创新中心石家庄050043

为深入了解顺向阵风来流对圆柱气动力和流场特性的影响,开展了雷诺数(Re)为1000的圆柱绕流三维大涡模拟,研究了不同频率顺向正弦来流对圆柱气动力和流场结构的影响规律,详细分析了升阻力系数、斯特劳哈尔数(St)、回流长度、分离角和尾... 详细信息

为深入了解顺向阵风来流对圆柱气动力和流场特性的影响,开展了雷诺数(Re)为1000的圆柱绕流三维大涡模拟,研究了不同频率顺向正弦来流对圆柱气动力和流场结构的影响规律,详细分析了升阻力系数、斯特劳哈尔数(St)、回流长度、分离角和尾流结构等参数的变化规律。顺向正弦来流速度为U=U_(0)+Asin(2πft),其中来流频率f的变化范围为0~0.3 Hz,U_(0)为平均速度,A为竖向正弦来流的振幅,设为0.15U_(0)。研究结果表明:圆柱阻力系数卓越频率(即主导频率)与正弦来流频率基本一致,升力系数存在3个明显的频率峰值,分别对应涡脱频率与来流频率之差、涡脱频率、涡脱频率与来流频率之和。随着正弦来流频率f增大,St先减小后增大,在f=0.25 Hz时达到最小值,而回流长度先增大后减小,且在f=0.15 Hz时达到最大值。当f≤St时,分离角不变,而顺流向最小速度逐渐增大;当f>St时,分离角逐渐增大.

关键词：圆柱绕流大涡模拟顺向正弦来流气动力流场

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Comparative Analysis of the Erosion Mechanism of Different Profiles in the Arcuate Foreshore under Typhoon Action

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Journal of Marine Science 2020年第3期2卷 28-34页

作者： Zishen Chen jitao yu Xinhua College of Sun Yat-sen University Guangzhou510520China School of Geography and Planning Sun Yat-sen UniversityGuangzhou510275China School of Surveying and Land Information Engineering Henan Polytech UniversityJiaozuo454000China

The comparison results of three beach profile data repeatedly measured before and after the typhoon in Shuidong Bay,west Guangdong province which show that there are significant differences in beach profile erosion and response process.And the changes of beach profile can be divided into:strong downward overall low shoreline regressive type and overall slight erosion shoreline regressive type.Application of the modified mildslope equation along three beach profile are simulated wave high reflection to the sea side,to the section vertical shore pressure gradient and including water roll force and radiation stress,the vertical shore forces one dimensional profile along the momentum conservation equation(radiation stress and water roll force)bottom friction and lateral mixing reaction between numerical solution,the momentum conservation equations of the wave increases the water flow velocity and section along the profile distribution of wave height and related forces.The analysis shows that the extent and difference of coastal erosion depend on the shoreline erosion mode stimulated by the maximum surge water of the coastal current and the maximum velocity of the coastal current and the dynamic state of the profile topography under the action of the profile location,morphology and incident wave elements.

关键词： Foreshore profile morphodynamics Shore erosion mechanism Wave setup Longshore current Longshore sediment transport rate

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基于增强多通道图注意力的推荐模型

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河北大学学报（自然科学版） 2024年第2期44卷 190-198页

作者：张昱苏仡琳李继涛陈广书张明魁北京建筑大学电气与信息工程学院建筑大数据智能处理方法研究北京市重点实验室北京100044 中国矿业大学深地空间科学与工程研究院深部岩土力学与地下工程国家重点实验室北京100083

图神经网络具备融合节点信息与拓扑结构的能力,近年来在推荐算法中得到了广泛的应用.然而,现有的基于图神经网络的推荐模型用户行为建模粒度较粗,用户特征学习算法对历史信息使用不足,两者阻碍了用户偏好特征的提取.针对以上问题,本文... 详细信息

图神经网络具备融合节点信息与拓扑结构的能力,近年来在推荐算法中得到了广泛的应用.然而,现有的基于图神经网络的推荐模型用户行为建模粒度较粗,用户特征学习算法对历史信息使用不足,两者阻碍了用户偏好特征的提取.针对以上问题,本文提出一种基于增强多通道图注意力的推荐模型(enhanced multi-channel graph attention based collaborative filtering recommendation model, EMGACF).在邻域聚合部分,采用多通道图注意力对细粒度用户评分等级建模,有效提升了模型对用户偏好的学习能力;在节点更新部分,提出基于增强自信息的节点更新算法,使用邻居节点聚合表示的同时保留了节点自身历史信息和内在偏好,提升了迭代过程中用户偏好的学习效果.实验部分在4种规模的常用推荐系统基准数据集上训练模型,实验结果表明,预测误差相比于主流模型降低了1.43%~7.81%.

关键词：图注意力用户偏好自编码器协同过滤

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不同浓度沼液及施用方式对小白菜生长效果的影响

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中国农业大学学报 2024年第8期29卷 86-94页

作者：娄雨李艳姜灵伟李明新王琦璋马继涛林聪段娜中国农业大学水利与土木工程学院/农业农村部设施农业工程重点实验室北京100083 三河市盈盛生物能源科技股份有限公司河北廊坊065000

为解决目前沼气工程存在的沼液处理难、现代农业化肥施用过量的问题,将不同稀释比例的沼液进行微生物菌剂预处理,获得不同浓度沼液液体肥,探究不同浓度沼液及其施用方式(叶面喷施和浇灌)对盆栽小白菜生长指标、光合指标和品质指标的影... 详细信息

为解决目前沼气工程存在的沼液处理难、现代农业化肥施用过量的问题,将不同稀释比例的沼液进行微生物菌剂预处理,获得不同浓度沼液液体肥,探究不同浓度沼液及其施用方式(叶面喷施和浇灌)对盆栽小白菜生长指标、光合指标和品质指标的影响。结果表明:(1)低浓度沼液通过叶面喷施可以促进小白菜的生长发育,施用稀释15~20倍的沼液效果最优;(2)高浓度沼液通过浇灌方式能够明显提高小白菜的各项生长品质指标,效果优于仅施尿素的化肥处理组,最佳施用方案为稀释1.5倍;(3)在相同氮素水平下,高浓度沼液浇灌对小白菜生长和品质的促进效果明显优于低浓度沼液叶面喷施。高浓度沼液具有可替代化肥的潜力,低浓度沼液可作为追肥施用,对作物养分起到一定的补充作用。利用微生物菌剂处理后的沼液液体肥栽培小白菜不仅可以显著提高其生长品质,还能够部分代替化肥施用,对农作物增收和保护环境都具有重要的现实意义。

关键词：沼液施用方式小白菜生长指标光合指标品质指标

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Rockburst Intensity Grade Prediction Model Based on Batch Gradient Descent and Multi-Scale Residual Deep Neural Network

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Computer Systems Science & Engineering 2023年第11期47卷 1987-2006页

作者： yu Zhang Mingkui Zhang jitao Li Guangshu Chen School of Electrical and Information Engineering Beijing University of Civil Engineering and ArchitectureBeijing100044China Beijing Key Laboratory of Intelligent Processing for Building Big Data Beijing University of Civil Engineering and ArchitectureBeijing100044China State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining&TechnologyBeijing100083China

Rockburst is a phenomenon in which free surfaces are formed during excavation,which subsequently causes the sudden release of energy in the construction of mines and tunnels.Light rockburst only peels off rock slices without ejection,while severe rockburst causes casualties and property loss.The frequency and degree of rockburst damage increases with the excavation depth.Moreover,rockburst is the leading engineering geological hazard in the excavation process,and thus the prediction of its intensity grade is of great significance to the development of geotechnical engineering.Therefore,the prediction of rockburst intensity grade is one problem that needs to be solved urgently.By comprehensively considering the occurrence mechanism of rockburst,this paper selects the stress index(σθ/σc),brittleness index(σ_(c)/σ_(t)),and rock elastic energy index(Wet)as the rockburst evaluation indexes through the Spearman coefficient method.This overcomes the low accuracy problem of a single evaluation index prediction method.Following this,the BGD-MSR-DNN rockburst intensity grade prediction model based on batch gradient descent and a multi-scale residual deep neural network is proposed.The batch gradient descent(BGD)module is used to replace the gradient descent algorithm,which effectively improves the efficiency of the network and reduces the model training time.Moreover,the multi-scale residual(MSR)module solves the problem of network degradation when there are too many hidden layers of the deep neural network(DNN),thus improving the model prediction accuracy.The experimental results reveal the BGDMSR-DNN model accuracy to reach 97.1%,outperforming other comparable models.Finally,actual projects such as Qinling Tunnel and Daxiangling Tunnel,reached an accuracy of 100%.The model can be applied in mines and tunnel engineering to realize the accurate and rapid prediction of rockburst intensity grade.

关键词： Rockburst prediction rockburst intensity grade deep neural network batch gradient descent multi-scale residual

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从ChatGPT看AI未来趋势和挑战

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计算机研究与发展 2023年第6期60卷 1191-1201页

作者：桑基韬于剑北京交通大学计算机学院北京100044 交通数据分析与挖掘北京市重点实验室(北京交通大学) 北京100044

在人工智能领域,ChatGPT作为一种重要的技术突破,引起了广泛的关注.本文将探讨ChatGPT在人工智能发展中的地位及其对未来AI的影响.首先,介绍了ChatGPT所展现出的优秀对话生成能力,使其几乎可以胜任所有自然语言处理任务,并将作为数据生... 详细信息

在人工智能领域,ChatGPT作为一种重要的技术突破,引起了广泛的关注.本文将探讨ChatGPT在人工智能发展中的地位及其对未来AI的影响.首先,介绍了ChatGPT所展现出的优秀对话生成能力,使其几乎可以胜任所有自然语言处理任务,并将作为数据生成器、知识挖掘工具、模型调度员、自然交互界面在各种场景得到应用.接着,分析了其在事实错误、毒害内容生成、安全性、公平性、可解释性、数据隐私等方面的局限,并讨论了作为辅助人类工具的ChatGPT明确能力边界和提高能力范围的重要性.然后,从概念经典表示对“真”定义进行了分析,并从概念三指不等价的角度阐释性了ChatGPT无法区分真假的原因.在论述AI未来时,从拓展应用、克服局限、探索理论分析了中短期技术趋势,并从感知、认知、情感、行为智能四个层面的关系讨论了长期发展路径.最后,探讨了ChatGPT作为认知智能的代表,对包括认知成本、教育要求、图灵测试认识、学术界的机遇与挑战、信息茧房、能源环境问题和生产力提升等方面可能产生的影响.

关键词： ChatGPT 人工智能发展对话生成技术挑战可信AI 社会影响

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Beach morphodynamic characteristics and classifications on the straight coastal sectors in the west Guangdong

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Journal of Geographical Sciences 2020年第7期30卷 1179-1194页

作者： DING yuanting yu jitao CHENG Huangxin School of Environmental Studies China University of GeosciencesWuhan 430074China School of Surveying and Land Information Engineering Henan Polytechnic UniversityJiaozuo 454000HenanChina Department of Landscape Architecture China University of GeosciencesWuhan 430074China

Currently beach morphodynamic classification is the most important foundation to conduct associated coastal geomorphological studies.This paper carried out beach morphodynamic classifications for 12 straight beaches on headland-bay coasts based on field survey and evaluated the applicability of the most widely used dimensional fall velocity parameter(Ω)and relative tidal range parameter(RTR).One reflective,five intermediate and six non-barred dissipative beaches were visually classified and sand size seemed to be a key factor to differentiate these beaches.The studied beaches were in relatively low wave energy environments(Hs3 KWm-1 and MSR<2 m.It was found that the model of the traditional winter-and-summer profiles was not applicable in the study area in despite of distinct wave seasonality.The studied beaches were more possible to hover around a limited range due to relatively low background wave environments and variability without considering typhoon impacts,which needs further research on actual breaker wave conditions and beach morphodynamic type responses to typhoon events.

关键词： beach morphodynamic type dimensionless fall velocity relative tidal range wave power level straight beaches

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High Li^(+)coordinated solvation sheaths enable high-quality Li metal anode

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InfoMat 2023年第5期5卷 40-54页

作者： Shizhi Huang yu-Peng Huang Yijie Xia Jingyi Ding Chengyuan Peng Lulu Wang Junrong Luo Xin-Xiang Zhang Junrong Zheng Yi Qin Gao jitao Chen Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijingthe People's Republic of China

An advance Li-sphere possessing a definitely regular morphology in Li deposition enables a well-defined more robust structure and superior solid-electrolyte interphase(SEI)to achieve high-efficiency long-term cycles in Li metal anode.Here,a new sight of high Li^(+)cluster-like solvation sheaths coordinated in a localized high-concentration NO_(3)^(-)(LH-LiNO_(3))electrolyte fully clarifies for depositing advanced Li spheres.Moreover,we elucidate a critical amorphouscrystalline phase transition in the nanostructure evolution of Li-sphere deposits during the nucleation and growth.Li-sphere anode exhibits ultrastable structural engineering for suppressing Li dendrite growths and rendering ultralong life of 4000 cycles in symmetrical cells at 2 mAcm^(-2).The as-constructed Li spheres/3DCMjLiFePO_(4)(LFP)full cell delivers a high capacity retention of 90.5%at 1 C after 1000 cycles,and a robust dendrite-free structure also stably exists in Li-sphere anode.Combined with high-loading LFP cathodes(6.6 and 10.9 mg cm^(-2)),superb capacity retentions are up to 96.5%and 92.5%after 800 cycles at 1 C,respectively.Cluster-like solvation sheaths with high Li^(+)coordination exert significant influence on depositing a highquality Li-sphere anode.

关键词： advanced Li-sphere deposition high-quality cycling stability high Li^(+)coordinated solvation sheaths localized high concentration NO3- ultra-stable structural engineering

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