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Probing the interaction between asphaltene-wax and its effects on the crystallization behavior of waxes in heavy oil via molecular dynamics simulation

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Petroleum Science 2024年第4期21卷 2839-2848页

作者： Yong Hu Xi Lu Hai-Bo Wang Ji-Chao fang Yi-Ning Wu Jian fang Sun SINOPEC Petroleum Exploration and Production Research Institute Shandong Key Laboratory of Oilfield Chemistry School of Petroleum Engineering China University of Petroleum (East China)

High content of asphaltenes and waxes leads to the high pour point and the poor flowability of heavy oil,which is adverse to its efficient development and its transportation in *** the interaction mechanism between asphaltene-wax is crucial to solve these problems,but it is still *** this paper,molecular dynamics simulation was used to investigate the interaction between asphaltenewax and its effects on the crystallization behavior of waxes in heavy *** show that molecules in pure wax are arranged in a paralleled *** wax molecules in heavy oil,which are close to the surface of asphaltene aggregates,are bent and arranged *** the mass fraction of asphaltenes in asphaltene-wax system(ωasp) is 0-25 wt%,the attraction among wax molecules decreases and the bend degree of wax molecules increases with the increase of ω*** ωaspincreases from 0 to 25 wt%,and the attraction between asphaltene-wax is stronger than that among *** causes that the wax precipitation point changes from 353 to 333 *** the ωaspincreases to 50 wt%,wax molecules are more dispersed owing to the steric hindrance of asphaltene aggregates,and the interaction among wax molecules transforms from attraction to *** causes that the ordered crystal structure of waxes can't be formed at normal ***,the asphaltene,with the higher molecular weight or the more hetero atoms,has more obvious inhibition to the formation of wax ***,resins also have an obvious inhibition on the wax crystal due to the formation of asphalteneresin aggregates with a larger *** results reveal the interaction mechanism between asphaltene-wax,and provide useful guidelines for the development of heavy oil.

关键词： Heavy oil Interaction mechanism Asphaltenes Waxes Molecular dynamics

Sufficient Conditions for Amalgamated 3-Manifolds to be ∂-Irreducible

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Chinese Annals of Mathematics,Series B 2024年第2期45卷 161-172页

作者： Bing fang Fengchun LEI Liang LIANG School of Mathematical Sciences Dalian University of TechnologyDalian 116024LiaoningChina School of Mathematics Liaoning Normal UniversityDalian 116029LiaoningChina

In this paper,the authors give some sufficient conditions for an amalgamated 3-manifold along a compact connected surface F with boundary to be ∂-irreducible in terms of distances between some kinds of vertex subsets ... 详细信息

关键词： ∂-Irreducibility Irreducibility Amalgamated 3-manifold Curve complex Arc complex

Kinetic investigations of reversible hydrogen storage in Li-Mg-B-H system

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Kinetic investigations of reversible hydrogen storage in Li-...

Thermo-hydro-mechanical (THM) coupled simulation of the land subsidence due to aquifer thermal energy storage (ATES) system in soft soils

第九届全国氢能学术会议

作者： P.J.Wang,z.z.fang,X.D.Kang,P.Wang Institute of Metal Research,China

＜正＞Emerging transportation applications based on hydrogen fuel cell technologies require the development of improved approaches for high capacity reversible storage of hydrogen. Recently,lithium borohydride（LiBH4） gains considerable interest as a potential hydrogen storage medium owing to its extremely high hydrogen capacity（18.5 wt.%）.However,the

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 1952-1966页

作者： Yang Wang Fengshou zhang fang Liu Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai200092China Shanghai Engineering and Technology Research Center of Shallow Geothermal Energy Shanghai200072China

Aquifer thermal energy storage(ATES)system has received attention for heating or cooling ***,it is well known that land subsidence becomes a major environmental concern for ATES ***,the effect of temperature on land subsidence has received practically no attention in the *** paper presents a thermo-hydro-mechanical(THM)coupled numerical study on an ATES system in Shanghai,*** water wells were installed for seasonal heating and cooling of an agriculture *** target aquifer at a depth of 74e104.5 m consisted of alternating layers of sand and silty sand and was covered with *** level,temperature,and land subsidence data from 2015 to 2017 were collected using field monitoring *** by data,we constructed a field scale three-dimensional(3D)model using TOUGH(Transport of Unsaturated Groundwater and Heat)and FLAC3D(Fast Lagrangian Analysis of Continua)equipped with a thermo-elastoplastic constitutive *** effectiveness of the numerical model was validated by field *** model was used to reproduce groundwater flow,heat transfer,and mechanical responses in porous media over three years and capture the thermo-and pressure-induced land *** results show that the maximum thermoinduced land subsidence accounts for about 60%of the total *** thermo-induced subsidence is slightly greater in winter than that in summer,and more pronounced near the cold well area than the hot well *** study provides some valuable guidelines for controlling land subsidence caused by ATES systems installed in soft soils.

关键词： Aquifer thermal energy storage(ATES) Land subsidence TOUGH-FLAC3D Thermo-elastoplastic constitutive model

Effect of various carbon materials on the reversible hydrogen storage of lithium borohydride

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Effect of various carbon materials on the reversible hydroge...

Probability-Enhanced Anchor-Free Detector for Remote-Sensing Object Detection

第九届全国氢能学术会议

作者： z.z.fang,P.Wang,X.D.Kang,H.M.Cheng Institute of Metal Research,China

One of the most challenging obstacles in implementing fuel cell technology for vehicular application is the lack of viable on-board hydrogen storage ***,decades of extensive efforts have been largely frustrated by the low gravimetric H-density in traditional metal/alloy ***,lithium borohydride(LiBH) has attracted considerable interest as a potential hydrogen storage medium due to its extremely high gravimetric(18.5

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Computers, Materials & Continua 2024年第6期79卷 4925-4943页

作者： Chengcheng Fan zhiruo fang Innovation Academy for Microsatellites of CAS Shanghai201210China Shanghai Engineering Center for Microsatellites Shanghai201210China College of Artificial Intelligence Nanjing Agricultural UniversityNanjing210095China

Anchor-free object-detection methods achieve a significant advancement in field of computer vision,particularly in the realm of real-time ***,in remote sensing object detection,anchor-free methods often lack of capability in separating the foreground and *** paper proposes an anchor-free method named probability-enhanced anchor-free detector(ProEnDet)for remote sensing object ***,a weighted bidirectional feature pyramid is used for feature ***,we introduce probability enhancement to strengthen the classification of the object’s foreground and *** detector uses the logarithm likelihood as the final score to improve the classification of the foreground and background of the *** is verified using the DIOR and NWPU-VHR-10 *** experiment achieved mean average precisions of 61.4 and 69.0 on the DIOR dataset and NWPU-VHR-10 dataset,*** achieves a speed of 32.4 FPS on the DIOR dataset,which satisfies the real-time requirements for remote-sensing object detection.

关键词： Object detection anchor-free detector probabilistic fully convolutional neural network remote sensing

Performance of iron-air battery with iron nanoparticle-encapsulated C-N composite electrode

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Frontiers in Energy 2024年第1期18卷 42-53页

作者： Can fang Xiangmei TANG Jiaoyan WANG Qingfeng YI School of Chemistry and Chemical Engineering Hunan University of Science and TechnologyXiangtan 411201China Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion Xiangtan 411201China

Highly efficient and stable iron electrodes are of great significant to the development of iron-air battery(IAB).In this paper,iron nanoparticle-encapsulated C–N composite(NanoFe@CN)was synthesized by pyrolysis using polyaniline as the C–N *** performance of the NanoFe@CN in different electrolytes(alkaline,neutral,and quasi-neutral)was investigated via cyclic voltammetry(CV).The IAB was assembled with NanoFe@CN as the anode and IrO_(2)+Pt/C as the *** effects of different discharging/charging current densities and electrolytes on the battery performance were also *** K_(2)SO_(4)electrolyte can effectively suppress the passivation of iron electrode,and the battery showed a good cycling stability during 180 charging/discharging *** to the pure nano-iron(NanoFe)battery,the NanoFe@CN battery has a more stable cycling stability either in KOH or NH_(4)Cl+KCl electrolyte.

关键词： energy storage and conversion metallic composites nanocomposites iron-air battery iron anode

Capturability-based Fuzzy Footstep Planner for a Biped Robot with Centroidal Compliance

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Journal of Bionic Engineering 2024年第1期21卷 84-100页

作者： zihan Xu Qin fang Yong Ren Chengju Liu Robot and Artificial Intelligence Lab(RAIL) College of Electronic and Information EngineeringTongji UniversityShanghai 201804China Applied Technology College Soochow UniversitySuzhou 215000China

Compliance motion and footstep adjustment are active balance control strategies from learning human subconscious *** force estimation without direct end-actuator force measurement and the optimal footsteps based on complex analytical calculation are still challenging tasks for elementary and kid-size position-controlled *** this paper,an online compliant controller with Gravity Projection Observer(GPO),which can express the external force condition of perturbations by the estimated Projection of Gravity(PoG)with estimation covariance,is proposed for the realization of disturbance absorption,with which the robustness of the humanoid contact with environments can be *** fuzzy footstep planner based on capturability analysis is proposed,and the Model Predictive Control(MPC)is applied to generate the desired *** fuzzification rules are well-designed and give the corresponding control output responding to complex and changeable external *** validate the presented methods,a series of experiments on a real humanoid robot are *** results verify the effectiveness of the proposed balance control framework.

关键词： Biped walking Centroidal compliance Gravity projection observer Fuzzy footstep planner

Kinetic model of vibration screening for granular materials based on biological neural network

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Particuology 2024年第5期88卷 98-106页

作者： zhan zhao Yan zhang fang Qin Mingzhi Jin School of Agricultural Engineering Jiangsu UniversityZhenjiang212013China Shandong Academy of Agricultural Machinery Sciences Ji'nan250100China

The kinetic model is the theoretical basis for optimizing the structure and operation performance of vibration screening *** this paper,a biological neurodynamic equation and neural connections were established according to the motion and interaction properties of the material under vibration *** material feeding to the screen and the material passing through apertures were considered as excitatory and inhibitory inputs,respectively,and the generated stable neural activity landscape was used to describe the material distribution on the 2D screen *** dynamic process of material vibration screening was simulated using discrete element method(DEM).By comparing the similarity between the material distribution established using biological neural network(BNN)and that obtained using DEM simulation,the optimum coefficients of BNN model under a certain screening parameter were determined,that is,one relationship between the BNN model coefficients and the screening operation parameters was *** screening parameters were randomly selected,and the corresponding relationships were established as a ***,with straw/grain ratio,aperture diameter,inclination angle,vibration strength in normal and tangential directions as inputs,five independent adaptive neuro-fuzzy inference systems(ANFIS)were established to predict the optimum BNN model coefficients,*** training results indicated that ANFIS models had good stability and *** flexibility and adaptability of the proposed BNN method was demonstrated by modeling material distribution under complex feeding conditions such as multiple regions and non-uniform rate.

关键词： Kinetic model Material distribution Vibration screening Biological neural network DEM simulation Adaptive neuro-fuzzy inference systems