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Effects of rye grass coverage on soil loss from loess slopes

International Soil and Water Conservation Research 2015年第3期3卷 170-182页

作者： yuequn dong Tingwu Lei Shuqin Li Cuiping Yuan Shumei Zhou Xiusheng Yang College of Water Resources and Civil Engineering China Agricultural UniversityBeijing100083China Agricultural Clear Watershed Group Institute of Agro-environment and Sustainable DevelopmentCAASBeijing 100081China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Science and Ministry of Water ResourcesYanglingShaanxi 712100China Beijing Grandtopeak Tianpinghang Land Plan and Design Co. Ltd.Beijing 100081China e School of Eonomics and Management Hebei University of Science and TechnologyShijiazhuang050018China University of Connecticut Department of Natural Resources and the EnvironmentStorrs 06269 United States

Vegetative coverage is commonly used to reduce urban slope soil *** experimental study on soil erosion under grass covered slopes is conventionally time and space *** this study,a new method is suggested to study the influences of vegetation coverage on soil erosion from a sloped loess surface under three slope gradients of 51,151,and 251;four rye grass coverages of 0%,25%,50%,and 75%;and three rainfall intensities of 60,90,and 120 mm/h with a silt-loamy loess *** grasses were planted in the field with the studied soil before being transplanted into a laboratory *** was allowed to resume growth for a period before the rain simulation *** showed that the grass cover reduced soil erosion by 63.90%to 92.75%and sediment transport rate by 80.59%to 96.17%under different slope gradients and rainfall *** sediment concentration/sediment transport rate from bare slope was significantly higher than from a grass-covered *** sediment concentration/transport rate from grass-covered slopes decreased linearly with grass coverage and increased with rainfall *** sediment concentration/transport rate from the bare slope increased as a power function of slope and reached the maximum value at the gradient of about 251,whereas that from grass-covered slope increased linearly and at much lower *** results of this study can be used to estimate the effect of vegetation on soil erosion from loess slopes.

关键词： Loess soil Rainfall simulation Slope Soil erosion Surface coverage

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不同示踪法测量砾石层中水流流速研究

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农业机械学报 2015年第4期46卷 141-146页

作者：陈丽燕雷廷武董月群颜燕中国农业大学水利与土木工程学院北京100083

采用室内试验,用平均粒径约2cm的砾石,在长4m、宽15cm、高50cm的水槽内堆积厚为5cm的砾石层,在坡度为4°、8°、12°和流量为3、6、12L/min条件下,距离电解质脉冲发生器0.3、0.6、0.9、1.2、1.5m处放置探针,测量电导率变化过程,计算水... 详细信息

采用室内试验,用平均粒径约2cm的砾石,在长4m、宽15cm、高50cm的水槽内堆积厚为5cm的砾石层,在坡度为4°、8°、12°和流量为3、6、12L/min条件下,距离电解质脉冲发生器0.3、0.6、0.9、1.2、1.5m处放置探针,测量电导率变化过程,计算水流的最大流速、优势流速和平均流速,并用染色剂示踪法对比砾石层中水流的最大测量流速。结果表明,试验所用各工况,流量对流速的影响不显著,坡度增大,流速明显增大。试验条件下,水流的优势流速变化范围为0.031～0.070m/s,优势流速与最大流速的比值稳定,在0.81～0.83之间。平均流速与优势流速的比值随坡长的增加逐渐增大,增长的速率逐渐减小并趋于稳定。平均流速与最大流速的比值在0.68～0.78之间,并随距离的增加稍有增大。

关键词：砾石层平均流速优势流速最大流速电解质示踪法

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脉冲边界模型测量冻土坡面径流流速与距离优选

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农业机械学报 2015年第2期46卷 146-152页

作者：董月群庄晓晖雷廷武马玉莹殷哲中国农业大学水利与土木工程学院北京100083

在室内不同坡度和流量条件下,用电解质脉冲边界模型以及染色剂示踪法进行冻土坡面和未冻土壤坡面径流流速测量的对比研究。采用长3.8 m、宽0.2 m和深0.08 m的试验土槽,用新疆阿克苏温宿县科其喀尔冰川流域草甸土,装土容重为1.0 g/cm^3... 详细信息

在室内不同坡度和流量条件下,用电解质脉冲边界模型以及染色剂示踪法进行冻土坡面和未冻土壤坡面径流流速测量的对比研究。采用长3.8 m、宽0.2 m和深0.08 m的试验土槽,用新疆阿克苏温宿县科其喀尔冰川流域草甸土,装土容重为1.0 g/cm^3、厚度5 cm,将土样饱和后冻结,制备用于试验的冻土坡面。为提高试验效率,采用在砂纸上粘贴土壤颗粒的方法模拟未冻土壤坡面。在坡度5°、10°和15°,流量12、24和48 L/min条件下,采用电解质脉冲边界模型方法和染色剂示踪方法测量冻土和未冻土壤坡面径流流速,并确定电解质脉冲边界模型方法的最优测量距离。结果表明：电解质脉冲边界模型测量流速随着测量距离增加呈指数增加,并逐渐趋于恒定。通过流速随沟长的变化关系,计算得到冻土坡面条件下,电解质脉冲边界模型测量流速与实际流速相差5%和10%,所需测量距离分别为1.7～2.7 m以及1.4～2.1 m。电解质脉冲边界模型法测得的冻土坡面径流流速随坡度、流量增大而增大,为0.45～0.98 m/s,是未冻土壤坡面径流流速的1.43倍。冻土坡面染色剂示踪法测得的流速较电解质脉冲边界模型测得的流速大3%～20%;未冻土壤坡面染色剂示踪法测得的流速较电解质脉冲边界模型测得的流速大6%～35%。

关键词：冻土坡面流速电解质脉冲边界模型优选距离

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Resonance mechanism of flapping wing based on fluid structure interaction simulation

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Chinese Journal of Aeronautics 2024年第5期37卷 243-262页

作者： Yueyang GUO Wenqing YANG Yuanbo dong dong XUE National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi'an 710072China Research&Development Institute of Northwestern Polytechnical University in Shenzhen Shenzhen 518063China Yangtze River Delta Research Institute of Northwestern Polytechnical University Taicang 215400China

Certain insect species have been observed to exploit the resonance mechanism of their *** order to achieve resonance and optimize aerodynamic performance,the conventional approach is to set the flapping frequency of flexible wings based on the Traditional Structural Modal(TSM)***,there exists controversy among researchers regarding the relationship between frequency and aerodynamic *** that the structural response of wings can be influenced by the surrounding air vibrations,an analysis known as Acoustic Structure Interaction Modal(ASIM)is introduced to calculate the resonant *** this study,Fluid Structure Interaction(FSI)simulations are employed to investigate the aerodynamic performance of flapping wings at modal frequencies derived from both TSM and ASIM *** performance is evaluated for various mass ratios and frequency ratios,and the findings indicate that the deformation and changes in vortex structure exhibit similarities at mass ratios that yield the highest aerodynamic ***,the flapping frequency associated with the maximum time-averaged vertical force coefficient at each mass ratio closely aligns with the ASIM frequency,as does the frequency corresponding to maximum ***,the ASIM analysis can provide an effective means for predicting the optimal flapping frequency for flexible ***,it enables the prediction that flexible wings with varying mass ratios will exhibit similar deformation and vortex structure *** paper offers a fresh perspective on the ongoing debate concerning the resonance mechanism of Flexible Flapping Wings(FFWs)and proposes an effective methodology for predicting their aerodynamic performance.

关键词： Flexible Flapping Wing(FFW) Acoustic Structure Interaction Modal(ASIM) Fluid Structure Interaction(FSI) Resonance mechanism Aerodynamic performance

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城市河道无人机高光谱水质监测与应用

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环境科学与技术 2021年第S1期44卷 289-296页

作者：董月群冒建华梁丹高世雄北控水务(中国)投资有限公司北京100102

高光谱成像技术具有大范围、快速、动态监测等优势,提供了一种客观监测大面积水体污染状况的方法,是水环境监测体系发展的趋势。文章以广东省鹤山市沙坪河为研究区域,通过无人机高光谱成像遥感数据对城市河网的Chl-a、COD、TN、TP、NH_(... 详细信息

高光谱成像技术具有大范围、快速、动态监测等优势,提供了一种客观监测大面积水体污染状况的方法,是水环境监测体系发展的趋势。文章以广东省鹤山市沙坪河为研究区域,通过无人机高光谱成像遥感数据对城市河网的Chl-a、COD、TN、TP、NH_(4)^(+)-N等水质参数进行了定量反演研究,研究结果显示,沙坪河原始光谱主要表现为4种不同的光谱曲线特征,对于沙坪河河道而言,导数光谱具有更高的估算精度。选择拟合效果较好的一阶导数对应的线性拟合模型(R^(2)介于0.85~0.96之间)为沙坪河水质指标定量反演模型,拟合效果次序依次为TN>NH_(4)^(+)-N>Chl-a>COD>TP。各指标的反演误差绝对值介于1.01%~35.81%之间,认为一阶导数对应的线性拟合模型具有较好的反演精度。通过高光谱水质监测仪测量的区域性结果,可快速获取城市河道水质分布情况,对城市水体环境治理具有重要意义。

关键词：城市河道无人机高光谱水质监测

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Finite-time Prescribed Performance Time-Varying Formation Control for Second-Order Multi-Agent Systems With Non-Strict Feedback Based on a Neural Network Observer

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 1039-1050页

作者： Chi Ma Dianbiao dong the School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China

This paper studies the problem of time-varying formation control with finite-time prescribed performance for nonstrict feedback second-order multi-agent systems with unmeasured states and unknown *** eliminate nonlinearities,neural networks are applied to approximate the inherent dynamics of the *** addition,due to the limitations of the actual working conditions,each follower agent can only obtain the locally measurable partial state information of the leader *** address this problem,a neural network state observer based on the leader state information is ***,a finite-time prescribed performance adaptive output feedback control strategy is proposed by restricting the sliding mode surface to a prescribed region,which ensures that the closed-loop system has practical finite-time stability and that formation errors of the multi-agent systems converge to the prescribed performance bound in finite ***,a numerical simulation is provided to demonstrate the practicality and effectiveness of the developed algorithm.

关键词： Finite-time control multi-agent systems neural network prescribed performance control time-varying formation control

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Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

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Chinese Journal of Chemical Engineering 2024年第1期65卷 43-53页

作者： dong Ma Qinhui Wang State Key Laboratory of Clean Energy Utilization Institute for Thermal Power EngineeringZhejiang UniversityHangzhou 310027China

The reduction of phosphogypsum(PG)to lime slag and SO_(2)using coke can effectively alleviate the environmental problems caused by ***,the PG decomposition temperature remains high and the product yield remains *** adding additives,the decomposition temperature can be further reduced and PG decomposition rate and product yield can be ***,the use of current additives such as Fe_(2)O_(3)and SiO_(2)brings the problem of increasing economic ***,it is proposed to use solid waste copper slag(CS)as a new additive to reduce PG to prepare SO2,which can reduce the cost and meet the environmental benefits at the same *** effects of proportion,temperature and thermostatic time on PG decomposition are investigated by experimental and kinetic analysis combined with FactSage thermodynamic calculations to optimize the roasting ***,the reaction mechanism is *** is found that adding CS to the coke and PG system can increase the rate of PG decomposition and SO_(2)yield while lowering the PG decomposition *** example,when the CS/PG mass ratio increases from 0 to 1,PG decomposition rate increases from 83.38%to 99.35%,SO_(2)yield increases from 78.62%to 96.81%,and PG decomposition temperature decreases from 992.4℃to 949.6℃.The optimal reaction parameters are CS/PG mass ratio of 1,Coke/PG mass ratio of 0.06 at 1100℃for 20 min with 99.35%PG decomposition rate and 96.81%SO_(2) *** process proceeds according to the following reactions:2CaSO_(4)+ 0.7C + 0.8Fe_(2)SiO_(4)→0.8Ca_(2)SiO_(4)+ 0.2Ca_(2)Fe_(2)O_(5)+ 0.4Fe_(3)O_(4)+2SO_(2)+ 0.7CO_(2)Finally,a process for decomposing PG with coke and CS is proposed.

关键词： Phosphogypsum Sulfur dioxide Copper slag Fluidized-bed Reduction Waste treatment

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Decision and Coordination in a Closed-Loop Supply Chain with Product Recycling Under Different Low-Carbon Regulations

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Journal of the Operations Research Society of China 2024年第3期12卷 695-728页

作者： Qian-dong dong Hai-Wen Xu School of Management and Engineering Nanjing UniversityNanjing210093JiangsuChina School of Science Civil Aviation Flight University of ChinaGuanghan618307SichuanChina

The implementation of recycling activity is of great significance to closed-loop supply chain ***’environmental awareness and governmental subsidy are considered in the two-echelon closed-loop supply *** types of decision-making structures are proposed under different carbon emission *** subsidy sharing mechanism is designed to resolve the channel members’conflict caused by double *** paper provides insight into the effect of environmental awareness and government subsidy under different low-carbon regulations on the supply chain benefit and social welfare via the game *** analysis results display that the government subsidy and subsidy sharing mechanism are profitably beneficial to the whole supply chain and social ***,a noteworthy result reveals that social welfare is not always directly proportional to consumers’environmental *** welfare decreases slightly with the increase in consumers’environmental awareness when consumers’environmental awareness is ***,social welfare will be significantly improved when consumers’environmental awareness increases beyond a certain threshold.

关键词： Closed-loop supply chain Recycling Coordination Social welfare Game theory Carbon emissions

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Resilient control of flexible hypersonic vehicles against unmatched distributed faults

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Chinese Journal of Aeronautics 2024年第5期37卷 60-70页

作者： dong ZHAO Wenjing REN School of Artificial Intelligence Anhui UniversityHefei 230601China Key Laboratory of System Control and Information Processing Ministry of EducationShanghai Jiao Tong UniversityShanghai 200240China School of Electrical Engineering and Automation Hefei University of TechnologyHefei 230009China

This paper studies a robust fault compensation and vibration suppression problem of flexible hypersonic *** controlled plant is represented by a cascade system composed of a nonlinear Ordinary Differential Equation(ODE)and an Euler-Bernoulli Beam Equation(EBBE),in which the vibration dynamics is coupled with the rigid dynamics and suffers from distributed faults.A state differential transformation is introduced to transfer distributed faults to an EBBE boundary and a longitudinal dynamics is refined by utilizing T-S fuzzy IF-THEN rules.A novel T-S fuzzy based fault-tolerant control algorithm is developed and related stability conditions are *** robust exponential stability and well-posedness are proved by using the modified l_(0)-semigroup based Lyapunov direct approach.A simulation study on the longitudinal dynamics of flexible hypersonic vehicles effectively verifies the validity of the developed theoretical results.

关键词： Flexible hypersonic vehicles ODE-EBBE cascade Robust exponential stability Unmatched distributed fault compensation Vibration suppression

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Modeling urban scale human mobility through big data analysis and machinelearning

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Building Simulation 2024年第1期17卷 3-21页

作者： Yapan Liu Bing dong Department of Mechanical&Aerospace Engineering Syracuse University263 Link HallSyracuseNY 13244USA

In the United States,the buildings sector consumes about 76%of electricity use and 40% of all primary energy use and associated greenhouse gas *** behavior has drawn increasing research interests due to its impacts on the building energy ***,occupant behavior study at urban scale remains a challenge,and very limited studies have been *** an effort to couple big data analysis with human mobility modeling,this study has explored urban scale human mobility utilizing three months Global Positioning System(GPS)data of 93,o00 users at Phoenix Metropolitan *** research extracted stay points from raw data,and identified users'home,work,and other locations by Density-Based Spatial Clustering ***,daily mobility patterns were constructed using different types of *** propose a novel approach to predict urban scale daily human mobility patterns with 12-hour prediction horizon,using Long Short-Term Memory(LSTM)neural network *** shows the developed models achieved around 85%average accuracy and about 86%mean *** developed models can be further applied to analyze urban scale occupant behavior,building energy demand and flexibility,and contributed to urban planning.

关键词： urban human mobility big data analysis urban scale occupant behavior recurrent neural networks

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