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Spatial-temporal distribution of debris flow impact pressure on rigid barrier

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Journal of Mountain Science 2019年第4期16卷 793-805页

作者： liu dao-chuan YOU Yong liu Jin-feng LI Yong ZHANG Guang-ze WANG Dong Key Laboratory of Mountain Hazards and Earth Surface Processes and Institute of Mountain Hazards and Environment Chinese Academy of Sciences University of Chinese Academy of Sciences China Railway Eryuan Engineering Group co. LTD

Grain composition plays a vital role in impact pressure of debris flow. Current approaches treat debris flow as uniform fluid and almost ignore its granular effects. A series of flume experiments have been carried out to explore the granular influence on the impact process of debris flow by using a contact surface pressure gauge sensor(Tactilus~?, produced by Sensor Products LLC). It is found that the maximum impact pressure for debris flow of low density fluctuates drastically with a long duration time while the fluctuation for flow of high density is short in time, respectively presenting logarithmic and linear form in longitudinal attenuation. This can be ascribed to the turbulence effect in the former and grain collisions and grainfluid interaction in the latter. The horizontal distribution of the impact pressure can be considered as the equivalent distribution. For engineering purposes, the longitudinal distribution of the pressure can be generalized to a triangular distribution, from which a new impact method considering granular effects is proposed.

关键词： Debris flow Impact force Grain composition Spatio-temporal distribution Dynamic coefficient

The siltation of debris flow behind check dam in the midstream of Bailong River

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Journal of Mountain Science 2018年第1期15卷 100-113页

作者： YUAN Dong liu Jin-feng YOU Yong liu dao-chuan SUN Hao ZHANG Li ZHOU Wen-bing Key Laboratory of Mountain Hazards and Earth Surface Process CAS Chengdu 610041 China Institute of Mountain Hazards and Environment CAS Chengdu 610041 China University of Chinese Academy of Sciences Beijing 100049 China

Siltation gradient and siltation length are important parameters for designing gravity check dams for debris flows,which directly affect the accuracy of estimates of interception *** present,siltation gradient calculations are based primarily on empirical values,and range from 0.4 to 0.95 times the channel slope *** middle reaches of the Bailong River are one of the four areas in China that are most severely affected by debris flow *** dams are widely employed in this mountainous ***,field studies of their capacity are *** this paper,the operations of check dams were *** on field investigation results and theoretical analysis,calculations for siltation gradient,siltation length,and dam storage capacity are *** impact of debris flow density,channel slope,and particle size weight percentages are *** calculations show that the theoretical values for siltation gradient are consistent with measured values with 83.6% accuracy;and theoretical values of siltation length are consistent with measured values with 91.6% *** results of this research are an important reference for optimal height and spacing of dams,estimation of dam storage capacity,and disaster prevention.

关键词： Debris flow Check dam Siltation gradient Siltation length Disaster prevention engineering

Estimating the maximum impact force of dry granular flow based on pileup characteristics

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Journal of Mountain Science 2019年第10期16卷 2435-2452页

作者： XIAO Si-you SU Li-jun JIANG Yuan-jun MEHTAB Alam LI Cheng liu dao-chuan Key Laboratory of Mountain Hazards and Earth Surface Processes and Institute of Mountain Hazards andEnvironmentChinese Academy of SciencesChengdu610041China University of Chinese Academy of Sciences Beijing100049China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing100101China Sichuan Highway Planning DesignResearch Institute LtdChengdu610041China

The maximum normal impact resultant force(NIRF)is usually regarded as the sum of the static earth pressure of the dead zone and the dynamic impact pressure of the flowing *** influence of the interaction between the flowing layer and dead zone on the impact force is *** this study,we classified two impact models with respect to the pileup characteristics of the dead ***,we employed the discrete element method to investigate the influences of the pileup characteristics on the impact force of dry granular flow on a tilted rigid *** the final pileup height is equal to the critical value,the maximum NIRF can be estimated using a hydrostatic model,because the main contribution to the maximum NIRF is the static earth pressure of the dead *** the final pileup height is less than the critical value,however,the particles in the dead zone are squeezed along the slope surface by the impact ofthe flowing layer on the dead zone,and because of shear effects,the flowing layer causes an entrainment in the dead *** results in a decrease in the volume of the dead zone at the moment of maximum NIRF with increases in the slope *** such,the maximum NIRF mainly comprises the instant impact force of the flowing layer,so hydro-dynamic models are effective for estimating the maximum *** models will benefit from further study of the components and distribution of the impact force of dry granular flow.

关键词： Dry granular flow Tilted retaining wall Impact force Discrete element method Pileup height

Characteristics of debris flow impact on a double-row slit dam

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Journal of Mountain Science 2023年第2期20卷 415-428页

作者： WANG Zhuang liu dao-chuan YOU Yong LYU Xiao-bo liu Jin-feng ZHAO Wan-yu SUN Hao WANG Dong-wei liu Yang Key Laboratory of Mountain Hazards and Earth Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Sichuan Highway Planning SurveyDesign and Research Institute Ltd.Chengdu 610041China Sichuan Tongchuan Engineering Technology Development Co. Ltd.Chengdu 610041China State Grid Sichuan Electric Power Transmission&Transformation Construction Co. Ltd.Chengdu 610051China

To accurately predict impact loads can ensure the safe operation of debris flow control *** instantaneous impact process is usually considered in the calculation of the debris flow impact force;however,the redistribution of an impact load after structural regulation is *** this study we deduced the theoretical calculation of a debris flow impact on a double-row slit dam,and carried out a verification experiment on the debris flow *** calculation model considers the influence of the debris flow properties,dam arrangement and pile *** results show that the impact force of the debris flow is obviously affected by the bulk *** the bulk density is 21 kg/m^(3),the maximum impact force on the pile dam is 1.15 times that when the bulk density is 15 kg/m^(3),but the time it takes for the debris flow to pass through the dam body is reduced by 60%.The larger the relative pile spacing,the more sufficient the flow space and the lower the maximum impact *** maximum impact force of relative pile spacing of 0.8 is 12%less than that of elative pile spacing of *** horizontal distribution of the impact force in the mud depth range is *** maximum impact force on the centre pier is 1.3 times that of a side pier,and the maximum impact force on the dam body appears at the top of the mud depth *** the vertical distribution of the impact force,the maximum impact force at the highest mud mark is approximately 70%of that of the *** the increase in the relative pile spacing,the longitudinal maximum impact force distribution first decreases and then increases.

关键词： Debris flow force Slit dam Fluctuations Flume model test

A calculation model to assess the crack propagation length of rock block in clastic flow

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Journal of Mountain Science 2020年第11期17卷 2636-2651页

作者： liu Yang YOU Yong liu Jin-feng ZHAO Shu-xi YANG Dong-xu liu dao-chuan liu Lin XIE Yan-fang YANG Kai-cheng Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of SciencesChengdu 610041China Institute of Exploration Technology Chinese Academy of Geological SciencesChengdu 611734China Sichuan Highway Planning SurveyDesign and Research Institute LtdChengdu 610041China Jiuquan Satellite Launch Center Jiuquan 732750China Southwest Electric Power Design Institute co. LTD.of China Power Engineering Consulting GroupChengdu 610041China Kunming Engineering co. LTDof Power Construction Corporation of ChinaKunming 650216China

The primary cracks in the rock block undergo series of steps and finally disintegrate,during this procession,the radius affects the impact force of rock block in clastic ***,it is essential to figure out the evolution mechanism of crack propagation for the design of engineering *** this study,based on fracture mechanics and Hertz contact theory,collision happened between rock block and slope surface is assumed to be elastic *** on the above assumption,the critical impact force of crack propagation is obtained,and a model used to calculate the crack propagation length in a single collision is ***,a rock fall site in Jiuzhai Valley was used to verify the calculation *** to the model,several key factors were identified to influence crack propagation length including falling height,initial equivalent radius,and recovery coefficient of slope ***,as a result of the orthogonal experiment,the influence of those factors on the crack propagation length was ranked,normal recovery coefficient>initial radius>initial falling *** addition,the kinetic energy of the rock block in the compression stage is transformed into elastic deformation energy,angular kinetic energy,and dissipated energy of crack *** to the increase of collisions,the kinetic energy is gradually transformed into angular kinetic energy,and the dissipated energy of crack propagation weights is *** conclusion,the crack propagation in rock block is a complicated progress,which is affected by multiple factors,especially falling height,initial equivalent radius,and recovery coefficient of slope *** study may provide guidance for the design of protective structure of clastic flows.

关键词： Clastic flows Rock block Crack propagation length Fracture mechanics Energy distribution Orthogonal Test

Polar solvent induced in-situ self-assembly and oxygen vacancies on Bi_(2)MoO_(6)for enhanced photocatalytic degradation of tetracycline

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Nano Research 2024年第6期17卷 4951-4960页

作者： Fangyan liu Dongyue Su Weizhen liu Baiquan liu chuan liu Hong Wang Mengye Wang State Key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510275China School of Materials Sun Yat-Sen UniversityShenzhen 518107China School of Environment and Energy Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and RecyclingSouth China University of TechnologyGuangzhou 510006China

It has been proved to be an effective route to efficiently ameliorate photocatalytic performance of catalysts via designing three-dimensional(3D)hierarchical nanostructures and constructing oxygen vacancies(VOs).However,controlling the self-assembly of organization into 3D hierarchical nanostructures while introducing VOs in photocatalysts remains a ***,we reported an ethylene glycol(EG)mediated approach to craft 3D hydrangea-structure Bi_(2)MoO_(6)with VOs for efficient photocatalytic degradation of *** manipulating the EG concentration during the fabrication process,the influence of EG concentration on the Bi_(2)MoO_(6)structure was systematically *** could promote the self-assembly of Bi_(2)MoO_(6)nanosheets to form a 3D hierarchical *** with 2D nanoplates,3D hierarchical architecture enhanced the surface area and the amount of active sites of Bi_(2)MoO_(6).In addition,the reduction effect of EG on metallic oxide enabled the generation of VOs in Bi_(2)MoO_(6).The VOs adjusted the electronic structure of Bi_(2)MoO_(6),which not only enhanced the light harvesting,but also facilitated the simultaneous utilization of photo-induced electrons and holes to form reactive oxygen species(·O2−and·OH)for the efficient tetracycline decomposition.3D Bi_(2)MoO_(6)hydrangea with VOs achieved a 79.4%removal efficiency of tetracycline after 75 *** work provides a simple yet robust EG-mediated strategy,which not only promotes the self-assembly of nano-catalysts into 3D hierarchical architectures,but also crafts tunable VOs for highly efficient photocatalysis.

关键词： three-dimensional(3D)hierarchical nanostructures tunable oxygen vacancies ethylene glycol(EG)-mediated strategy bismuth molybdate photocatalytic degradation tetracycline

Experimental investigation on using CO_(2)/H_(2)O emulsion with high water cut in enhanced oil recovery

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Petroleum Science 2024年第2期21卷 974-986页

作者： Xi-dao Wu Peng Xiao Bei liu Guang-Jin Chen Jian-Hua Pang State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Ocean Intelligence Technology Center Shenzhen Institute of Guangdong Ocean UniversityShenzhen518120GuangdongChina

CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility ***,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely *** this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil ***,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT ***,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary ***,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were *** results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) *** inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was ***_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water ***,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,*** work may provide guidelines for EOR using CO_(2) emulsions with high water cut.

关键词： CO_(2)/H_(2)O emulsion High water cut CO_(2) mobility control Enhanced oil recovery

Mismatch loss analysis of solar array output power on stratospheric airship during flight

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Chinese Journal of Aeronautics 2024年第2期37卷 371-384页

作者： Siyu liu Kangwen SUN Haoquan LIANG Xinzhe JI Tong ZOU chuan SHAN School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Yunnan Innovation Institute Beihang UniversityKunming 650233China Institute of Unmanned System Beihang UniversityBeijing 100191China

Stratospheric airships are long-endurance aerostats and have broad *** of the energy required for their operation is obtained from solar radiation,which makes accurate calculation of the energy output from the solar array crucial to the design and flight planning of the ***,the status of each photovoltaic module in the solar array may differ due to the airship curvature,resulting in mismatch losses and lowered output power,which has not been widely *** this paper,an irradiation model and a thermal model are established based on the actual arrangement of the *** output power model is established considering the non-uniform radiation in the *** mismatch losses of the array are analyzed under different flight *** output power of the solar array is decreased by up to 31.6%compared to the ideal ***,the proportion of mismatch losses increases with latitude,but the maximum mismatch loss power occurs at ***,an array reconfiguration method is proposed based on the irradiance dispersion index and position dispersion *** reconfigured array increases output power by 11.5%and can maintain energy balance in continuous *** results can be used to correct the overestimation of the output power during the airship design or to guide the configuration of the solar array.

关键词： Stratospheric airship Solar panels Solar energy Non-uniform irradiation Mismatch loss assessment Reconfiguration

A Dual Closed-Loop Digital Twin Construction Method for Optimizing the Copper Disc Casting Process

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 581-594页

作者： Zhaohui Jiang chuan Xu Jinshi liu Weichao Luo Zhiwen Chen Weihua Gui IEEE the School of Automation Central South UniversityChangsha 410083China the Peng Cheng Laboratory Shenzhen 518000China

The copper disc casting machine is core equipment for producing copper anode plates in the copper metallurgy *** copper disc casting machine casting package motion curve(CPMC) is significant for precise casting and efficient ***,the lack of exact casting modeling and real-time simulation information severely restricts dynamic CPMC *** this end,a liquid copper droplet model describes the casting package copper flow pattern in the casting ***,a CPMC optimization model is proposed for the first *** top of this,a digital twin dual closed-loop self-optimization application framework(DT-DCS) is constructed for optimizing the copper disc casting process to achieve self-optimization of the CPMC and closed-loop feedback of manufacturing information during the casting ***,a case study is carried out based on the proposed methods in the industrial field.

关键词： Copper disc casting machine digital twin(DT) mechanism modeling self-optimization