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Structural relaxation and avalanche dynamics of particle piles under vertical vibration

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Particuology 2022年第9期20卷 65-74页

作者： Lizhuo Zhu haifeng Lu Xiaolei Guo haifeng liu Shanghai Engineering Research Center of Coal Gasifiication East China University of Science and TechnologyShanghai 200237China

Granular matter can exhibit solid or liquid behavior,which contains complex physical *** this work,we experimentally investigated the structural relaxation and avalanche dynamics of particle piles under vertical *** influence of vibration parameters on the avalanche process was *** morphological features of avalanches were recorded and classified using high-speed *** effects of vibration parameters and particle properties on the relaxation mode are *** is found that the evolution of particle pile height with time can be described by an exponential decay *** relaxation rate and avalanche characteristics of four types of particles with different sizes are *** the same acceleration level,for two larger particles,a smaller amplitude(A=0.025 mm)leads to a faster relaxation rate,while for two smaller particles,a large amplitude(A=0.500 mm)leads to a faster relaxation *** analogy powder surface tension is introduced to address the cohesion and flowability evolution of particles under vibration.

关键词： Particle pile Vertical vibration Avalanche Flowability

Characterization of powder flow properties from micron to nanoscale using FT4 powder rheometer and PT-X powder tester

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Particuology 2023年第4期75卷 1-10页

作者： Hui Du haifeng Lu Jie Tang haifeng liu Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyShanghai200237China

The rapid development of nanotechnology has led to a need to further understand the physical char-acteristics of *** this paper,the flow characteristics of micro-nano alumina particles with different particle sizes were *** FT4 powder rheometer and the PT-X powder tester were used to measure the compression,friction,and dynamic properties of *** compressibility increased significantly as the particle size decreased from 27 μm to 30 *** distribution in the silo was measured and predicted by Janssen's theory,with errors mostly less than 10%.The basic flow energy and the specific energy of the three powders were 4983,1734,and 244 mJ,and 6.80,11.70,and 6.70 mJ/g,respectively,indicating that there was no linear relationship between the change in flowability and particle *** dynamic properties of the powders change from particle-dominated to agglomeration-dominated as the particle size *** conclusion is supported by the results of field emission scanning electron microscopy.

关键词： Micro-nano powders Flow properties Compressibility Frictional properties Pressure distribution

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生物3D打印仿生支架促进肩袖损伤后的愈合

中国组织工程研究 2025年第22期29卷 4761-4770页

作者：徐杰酒精卫刘海峰赵斌山西医科大学第二医院骨科山西省太原市030000 骨与软组织损伤修复山西省重点实验室山西省太原市030000

背景:大多数肩袖损伤发生于冈上肌腱,由于肌腱组织缺少血管以及肩袖复杂的解剖结构,临床治疗效果非常有限。组织工程技术和干细胞生物学的快速发展为提高肌腱修复质量带来了新的希望。目的:通过生物3D打印技术制备人脐带间充质干细胞/... 详细信息

背景:大多数肩袖损伤发生于冈上肌腱,由于肌腱组织缺少血管以及肩袖复杂的解剖结构,临床治疗效果非常有限。组织工程技术和干细胞生物学的快速发展为提高肌腱修复质量带来了新的希望。目的:通过生物3D打印技术制备人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架,观察该支架修复肩袖损伤的效果。方法:(1)体外细胞实验:制备明胶微载体,将人脐带间充质干细胞接种于明胶微载体表面构建组织工程化干细胞。制备甲基丙烯酸酐化明胶水凝胶打印墨水,使用甲基丙烯酸酐化明胶水凝胶打印墨水重悬组织工程化干细胞,放入3D打印机的生物墨水容器中进行打印,蓝光照射固化5 min后即得人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架。通过死活染色、CCK-8实验检测支架内人脐带间充质干细胞的活性。(2)动物体内实验:采用随机区组设计方法将24只SD大鼠随机4组,每组6只:正常组不进行任何处理,肩袖损伤组、单纯支架组、细胞支架组建立冈上肌腱撕裂的肩袖损伤模型,单纯支架组、细胞支架组造模后分别将甲基丙烯酸酐化明胶支架、人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架植入肌腱损伤处。术后4周,分别进行大鼠行为学测试及肩袖冈上肌腱组织学病理组织形态观察。结果与结论:(1)体外细胞实验:死活染色结果显示,明胶微载体可减轻3D打印过程对人脐带间充质干细胞造成的损伤,随着培养时间的延长,支架内的人脐带间充质干细胞存活率升高;CCK-8实验结果显示,随着培养时间的延长,支架内的人脐带间充质干细胞活性无明显变化。(2)动物体内实验:行为学测试结果显示,相较于肩袖损伤组、单纯支架组,细胞支架组大鼠四肢运动功能明显改善;肩袖冈上肌腱苏木精-伊红与Masson染色结果显示,相较于肩袖损伤组、单纯支架组,细胞支架组肌纤维排列较规律,无明显的炎性细胞浸润,胶原容积百分比降低;免疫荧光染色结果显示,相较于肩袖损伤组、单纯支架组,细胞支架组肩袖冈上肌腱内白细胞介素6、肿瘤坏死因子α蛋白表达明显降低。(3)结果表明,生物3D打印的人脐带间充质干细胞/甲基丙烯酸酐化明胶复合支架可促进肩袖损伤组织修复再生。

关键词：肩袖损伤冈上肌腱损伤人脐带间充质干细胞细胞治疗组织工程化干细胞生物支架甲基丙烯酸化明胶生物3D打印

Characterization of the flowability dynamics of granular material flowing down a narrow channel

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Particuology 2020年第6期18卷 72-82页

作者： Ningsheng Wang haifeng Lu Jianliang Xu Xiaolei Guo haifeng liu Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education East China University of Science and TechnologyP.O.Box 272Shanghai 200237China Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyP.O.Box 272Shanghai 200237China Ningbo Ruiling Institute for Energy and Environment Solutions Ningbo 315500China

The flowability of granular material is commonly determined from shear cell tests,but in the real world,the granular flow is quite different in many *** this paper,the flowabilities in a narrow channel of five different granular materials were *** flow parameters of the granular flows were determined to classify the flowabil让*** flow surface velocities and flow heights and thicknesses were measured,and it was found that the mean shear rates in the linear portions of the velocity profiles in crease with both flow rates and incli nation.A universal parameter,the ratio of the sine of the inclin ation to the shear rate in the linear part of the velocity profile,is proposed as a *** constant is independent of particle *** addition,a flowability parameter,the ratio of the mean shear rate to the cosine of the inclination,is proposed to characterize the friction between the particles in the flowing granular material.

关键词： Dynamic characterization Granular flow Velocity profile Flowability Channel

Experimental Study on the Dynamic Mechanical Properties of Reinforced Concrete under Shock Loading

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Acta Mechanica Solida Sinica 2016年第1期29卷 22-30页

作者： haifeng liu Jie Fu Jianguo Ning Department of Civil and Hydraulic Engineering Ningxia University State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology

A simple experimental method was introduced to study the mechanical properties of reinforced concrete under shock loading. The one-stage light gas gun was used to test the me- chanical properties of reinforced concrete with different reinforcement ratios under various impact velocities. Three Mn-Cu piezoresistive pressure gauges embedded in the target were used to record the voltage-time signals, from which the stress-strain curves of reinforced concrete were obtained using Lagrangian analysis. Experimental results indicated that the load-bearing capacities of re- inforced concrete increased greatly with the impact velocity and the reinforcement ratio. The peak stress of the shock wave decreased exponentially with the propagation distance.

关键词： reinforced concrete shock loading Lagrangian analysis dynamic mechanical properties

Influences of regeneration atmospheres on structural transformation and renderability of fluidized catalytic cracking catalyst

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Chinese Journal of Chemical Engineering 2023年第11期63卷 71-80页

作者： Haigang Zhang Zhongjie Shen Jianhong Gong haifeng liu National Energy Coal Gasification Technology Research and Development Center and Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyShanghai 200237China Sinopec Research Institute of Petroleum Processing Beijing 100083China

The regeneration of fluidized catalytic cracking(FCC)catalysts is an essential process in petroleum *** current study focused the regeneration reaction characteristics of spent fluidized catalytic cracking catalyst(SFCC)at different atmospheres with influences on pore evolution and activity,for a potential way to reduce emission,produce moderate chemical product(CO),and maintain catalyst *** results show that regeneration in air indicates a satisfaction on removing coke on the catalyst surface while giving a poor effect on eliminating the coke inside *** is attributed that the combustion in air led to a higher temperature and further transformed kaolinite phase to silicaaluminum spinel crystals,which tended to collapse and block small pores or expand large pores,with similar results observed in pure O_(2)***,catalysts regenerated in O_(2)/CO_(2)diminished the combustion damage to the pore structure,of which the micro porosity after regeneration increased by 32.4% and the total acid volume rose to 27.1%.The regeneration in pure CO_(2)displayed low conversion rate due to the endothermic reaction and low *** coexistence of gasification and partial oxidation can promote regeneration and maintain the original structure and good ***,a mechanism of the regeneration reaction at different atmospheres was revealed.

关键词： Fluidized catalytic cracking Coke deposit Regeneration Pore structure Gasification and combustion

Dynamic mechanical behavior and the constitutive model of concrete subjected to impact loadings

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1745-1760页

作者： NING JianGuo liu haifeng SHANG Lin State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China School of Civil and Hydraulic Engineering Ningxia UniversityYinchuan 750021China

Based on the theory of consecutive damage mechanics, micro-mechanics, statis-tics and the visco-plastic constitutive equation of Perzyna, a coupled model of damage and plasticity is developed to describe the complex behavior of concrete subjected to impact loadings. In this model, some suppositions about deformation of the material and evolution of the damage are made. First, concrete is macro-scopically assumed to be homogeneous and consecutive, while it is microscopi-cally filled with large amounts of micro-crack and micro-void defects. Second, the damage evolution of the micro-cracks is caused by the nucleation, growth and coalescence of the micro-cracks due to the interior tensile stress in concrete, which leads to a degradation in the strength and stiffness of concrete. Third, compaction of concrete is physically a collapse of the material micro-void. It pro-duces irreversible plastic strains in the material and, at the same time, an increase in the bulk modulus. Fourth, there is no interaction between the micro-crack and the micro-void. Last, when the damage reaches a critical value, the concrete may fail totally. The model parameters for concrete are determined by plate impact ex-periments. The model predictions fit the experimental results well. So the model can be used to simulate the dynamic mechanical behavior of concrete under impact loadings.

关键词： concrete impact behavior damage evolution constitutive model

Characteristics of single petcoke particle during the gasification process at high temperatures

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Chinese Journal of Chemical Engineering 2019年第10期27卷 2427-2437页

作者： Ming liu Zhongjie Shen Qinfeng Liang Jianliang Xu haifeng liu Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education East China University of Science and TechnologyShanghai 200237China Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyShanghai 200237China

Particle concentration significantly affected the gasification of petcoke particles according to our previous *** this work,gasification characteristics and morphological evolution of single petcoke particle were investigated using a high temperature stage microscope experimental *** results showed that the reaction temperature significantly affected the reactivity of petcoke in the temperature range of 1200–1300°*** the promoting effect on gasification reactivity decreased with further increasing the reaction temperature,the SEM analysis demonstrated the pore development during the gasification process,which attributed to the increase of reaction rate with *** Raman analysis,HRTEM and SEM–EDX analysis showed that the heterogeneous graphitization of petcoke and non-uniform distribution of catalytic elements in petcoke attributed to the development of surface pores with limited *** gasification mechanism of petcoke particle can be briefly described as the reaction rate mainly contributed from the fast-reaction ***,the pore development in fast-reaction area also enlarged the surface area of petcoke particle.

关键词： Petcoke particle Reaction kinetics Pore growth Reaction mechanism High temperature gasification

Outlook of Energy Storage via Large-Scale Entrained-Flow Coal Gasification

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Engineering 2023年第10期29卷 50-54页

作者： Zhongjie Shen Junguo Li haifeng liu National Energy Coal Gasification Technology Research and Development Center East China University of Science and TechnologyShanghai 200237China Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyShanghai 200237China School of Innovation and Entrepreneurship Southern University of Science and TechnologyShenzhen 518055China

*** The decarbonization of the energy sector,which greatly relies on fossil-fuel energy,requires urgent action on a global scale to reduce carbon emissions to a net-zero state and to mitigate the effects of climate change[1,2].With a multi-level global energy transition already underway,there is an inevitable trend to use renewable energy to replace traditional fossil-fuel energy.

关键词： Outlook Storage Flow