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Research status and prospects of the fractal analysis of metal material surfaces and interfaces

International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 20-38页

作者： Qinjin Dai Xuefeng Liu Xin Ma Shaojie Tian Qinghe Cui Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China Laboratory for Advanced Materials Processing of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Mechanical and Electrical Engineering Xinjiang Institute of EngineeringUrumqi 830023China

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine *** analysis has been used to characterize the shapes of metal materials at various scales and *** methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and ***,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal *** the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear *** relationship between the fractal dimensions and properties of metal material surfaces and interfaces is *** from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be *** is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

关键词： metal material surfaces and interfaces fractal analysis fractal dimension homogeneity

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fractal analysis of retinal vasculature in normal subjects on ultra-wide field fluorescein angiography

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International Journal of Ophthalmology(English edition) 2020年第7期13卷 1109-1114页

作者： Wen-Ying Fan Alan Fleming Gavin Robertson Akihito Uji Jano van Hemert Michael Singer Min Sagong Michael Ip SriniVas R.Sadda Beijing Tongren Eye Center Beijing Tongren HospitalBeijing Ophthalmology and Visual Sciences Key LaboratoryCapital Medical UniversityBeijing 100730China Doheny Image Reading Center Doheny Eye InstituteLos AngelesCA 90086USA Department of Ophthalmology David Geffen School of Medicine at UCLALos AngelesCA 90095USA Optos PLC Dunfermline KY118GRUnited Kingdom Department of Ophthalmology Medical Center Ophthalmology AssociatesSan AntonioTX 78258USA

AIM: To evaluate the fractal feature of the retinal vasculature of normal eyes on a stereographic projected and montaged ultra-wide field(UWF) fluorescein angiography(FA).METHODS: Prospective, observational, cross-sectional study. Totally 59 eyes of 31 normal subjects were imaged using the Optos 200 Tx. Images obtained at different gaze angles stereographically projected and montaged. The early-phase UWF FA frames were processed to segment the retinal vasculature and the results were exported as binary masks. The fractal dimension(FD) was calculated using the box-counting ***: The global FD for the entire retina was 1.6±0.04, with no difference between males and females(1.59±0.04 vs 1.61±0.04, P=0.084) or between right and left eyes(1.6±0.04 vs 1.6±0.05, P=0.61). FD was nonuniformly distributed among four quadrants(P0.05).CONCLUSION: fractal geometry is non-uniformly distributed across the retina in normal eyes and decreases from the fovea to the far-periphery. Subjects with an older age tend to have a smaller FD, however, the FD in the farperiphery does not appear to be influenced by age.

关键词： fractal analysis retina ultra-wide field fluorescein angiography normal subject

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Hidden periodicity in Stripe 82 with Saraswati supercluster—a fractal analysis

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Communications in Theoretical Physics 2021年第1期73卷 71-77页

作者： Vimal Raj M S Swapna S Sankararaman Department of Optoelectronics University of KeralaTrivandrumKerala695581-India

The manuscript attempts to explore the periodicity in the distribution of galaxies in the recently reported Saraswati supercluster and the Stripe 82 region containing it as an *** report of 120 Mpc periodicity in the Abell galaxy clusters by power spectrum analysis is the motivation behind the *** power spectral analysis across the central part of the Stripe 82 region shows a periodic variation of 3.09°or 71 Mpc in fractal dimension whereas an average angular periodicity of 3.45°or 94 Mpc is observed across the Stripe 82 *** refers to the periodicity of complexity or cluster density of galaxy *** texture of the distribution pattern understood through lacunarity analysis indicates a near symmetric *** dimensions like box-counting dimension,information dimension and correlation dimension are also found through multifractal *** the information dimension tells about the distribution density of galactic points,the correlation dimension details the distribution of galaxies in the neighbourhood.

关键词： galaxy distribution fractal analysis multifractals lacunarity Saraswati supercluster Stripe 82

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Process Dynamics and fractal analysis of New Phase Formation in Thermal Processes

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Journal of Thermal Science 2001年第2期10卷 153-158,115页

作者： WangJ ShenZ.W 等 DepartmentofChemicalEngineering DalianUniversityofTechnologyDalian116012China DepartmentofMathemati

Boiling and fouling are taken as typical examples of new phase formation process to be analyzed and discussed in this paper. The process dynamics of nucleate boiling is analyzed and its mechanism is discussed from the view point of self-organization. Fouling, which is a more complicated phenomenon of new phase formation, involves series of underlying processes. The morphology and fractal analysis of fouling on low-energy surface and that with fouling inhibitors are studied and discussed. It is suggested that considering the process dynamics, fractal analysis and self-organization, a new avenue of research should be found.

关键词： new phase formation process dynamics fractal analysis self-organization thermal process

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Rheological properties and fractal-rheology analysis of peanut protein isolate suspension

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International Journal of Agricultural and Biological Engineering 2020年第6期13卷 220-226页

作者： Chonghao Bi Shangyi Chi Zhe Hua Dong Li Zhigang Huang Yi Liu School of Materials Science and Mechanical Engineering Beijing Technology and Business UniversityBeijing 100048China School of Mechanical and Electronic Control Engineering Beijing Jiaotong UniversityBeijing 100044China College of Engineering China Agricultural UniversityBeijing 100083China Beijing Key Laboratory of Quality Evaluation Technology for Hygiene and Safety of Plastics Beijing 100048China

This study focuses on the non-linear rheological property and microstructure of peanut protein isolate(PPI)aggregation *** impact of higher harmonics(I3 and I5)on fundamental stress wave during large amplitude oscillatory shear test was *** test show that storage modulus G′and loss modulus G″increased with increasing PPI *** non-linear viscoelastic properties of PPI suspension with different concentration were *** confocal laser-scanning microscopy method,this research explored the microstructure of PPI suspension as well as the fractal *** new critical strain indirect method combined with Wu-Morbidelli model to calculate the fractal dimension(2.9225)is very close to the actual fractal dimension(2.9206).Fourier Transform Rheology was adopted to get the new critical strain for fractal dimension calculation,which was proved to be feasible.

关键词： peanut protein isolate suspension rheological property microstructure fractal analysis

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Microcrack analysis of Sanya grantite fragments from rockburst tests

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Mining Science and Technology 2010年第2期20卷 238-243页

作者： HE, Manchao NIE, Wen HAN, Liqiang LING, Lijing state key laboratory of geomechanics and deep underground engineering beijing 100083china school of mechanics & civil engineering china university of mining & technologybeijing 100083china school of mechanics & civil engineering china university of mining & technologybeijing 100083china

Fractures running along a plane reflect the cracking *** this paper uniaxial and rockburst tests on a group of granite specimens from Sanya province are *** electron microscopic imaging was used to characterize the *** fracture mechanics were used to analyze the microcracks in terms of both the crack type and the mineral constituent.A statistical analysis showed that the area of inter-granular cracking exceeds that of intra-granular *** types of crack were observed in the cracked *** percentage of intra-granular cracks in fragments from rockburst tests exceeds that from uniaxial compression *** results also showed that feldspar deformation was the main cause of fracture and that the consolidation along quartz grain boundaries was another weak area in the *** along quartz grains had enough energy to enter the quartz crystal in the rockburst *** these results contribute to further research on rockburst mechanics.

关键词： granite rockburst medium fragment quartz feldspar fractal analysis

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Effect of cyclic hydraulic stimulation on pore structure and methane sorption characteristics of anthracite coal: A case study in the Qinshui Basin, China

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Petroleum Science 2024年第5期21卷 3271-3287页

作者： Rui-Shuai Ma Ji-Yuan Zhang Qi-Hong Feng Xue-Ying Zhang Yan-Hui Yang State Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongPR China School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongPR China Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)) Ministry of EducationQingdao266580ShandongPR China Shandong Institute of Petroleum and Chemical Technology Dongying257000ShandongPR China PetroChina Research Institute of Petroleum Exploration&Development Beijing 100083PR China PetroChina Huabei Oilfield Company Renqiu062552HebeiPR China

The cyclic hydraulic stimulation(CHS) has proven as a prospective technology for enhancing the permeability of unconventional formations such as coalbeds. However, the effects of CHS on the microstructure and gas sorption behavior of coal remain unclear. In this study, laboratory tests including the nuclear magnetic resonance(NMR), low-temperature nitrogen sorption(LTNS), and methane sorption isotherm measurement were conducted to explore changes in the pore structure and methane sorption characteristics caused by CHS on an anthracite coal from Qinshui Basin, China. The NMR and LTNS tests show that after CHS treatment, meso- and macro-pores tend to be enlarged, whereas micropores with larger sizes and transition-pores may be converted into smaller-sized micro-pores. After the coal samples treated with 1, 3, 5 and 7 hydraulic stimulation cycles, the total specific surface area(TSSA)decreased from 0.636 to 0.538, 0.516, 0.505, and 0.491 m^(2)/g, respectively. fractal analysis based on the NMR and LTNS results show that the surface fractal dimensions increase with the increase in the number of hydraulic stimulation cycles, while the volume fractal dimensions exhibit an opposite trend to the surface fractal dimensions, indicating that the pore surface roughness and pore structure connectivity are both increased after CHS treatment. Methane sorption isothermal measurements show that both the Langmuir volume and Langmuir pressure decrease significantly with the increase in the number of hydraulic stimulation cycles. The Langmuir volume and the Langmuir pressure decrease from 33.47 cm^(3)/g and 0.205 MPa to 24.18 cm^(3)/g and 0.176 MPa after the coal samples treated with 7 hydraulic stimulation cycles, respectively. The increments of Langmuir volume and Langmuir pressure are positively correlated with the increment of TSSA and negatively correlated with the increments of surface fractal dimensions.

关键词： Coalbed methane Cyclic hydraulic stimulation Pore structure Methane sorption characteristics fractal analysis

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Investigation of non-premixed flame combustion characters in GO_2/GH_2 shear coaxial injectors using non-intrusive optical diagnostics

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Science China(Physics,Mechanics & Astronomy) 2015年第12期58卷 167-179页

作者： DAI Jian YU NanJia CAI GuoBiao Beijing University of Aeronautics and Astronautics

Single-element combustor experiments are conducted for three shear coaxial geometry configuration injectors by using gaseous oxygen and gaseous hydrogen(GO2/GH2) as propellants. During the combustion process, several spatially and time- resolved non-intrusive optical techniques, such as OH planar laser induced fluorescence(PLIF), high speed imaging, and infrared imaging, are simultaneously employed to observe the OH radical concentration distribution, flame fluctuations, and temperature fields. The results demonstrate that the turbulent flow phenomenon of non-premixed flame exhibits a remarkable periodicity, and the mixing ratio becomes a crucial factor to influence the combustion flame length. The high speed and infrared images have a consistent temperature field trend. As for the OH-PLIF images, an intuitionistic local flame structure is revealed by single-shot instantaneous images. Furthermore, the means and standard deviations of OH radical intensity are acquired to provide statistical information regarding the flame, which may be helpful for validation of numerical simulations in future. Parameters of structure configurations, such as impinging angle and oxygen post thickness, play an important role in the reaction zone distribution. Based on a successful flame contour extraction method assembled with non-linear anisotropic diffusive filtering and variational level-set, it is possible to implement a fractal analysis to describe the fractal characteristics of the non-premixed flame contour. As a result, the flame front cannot be regarded as a fractal object. However, this turbulent process presents a self-similarity characteristic.

关键词： liquid rocket engine shear coaxial injector non-intrusive optical techniques image segmentation fractal analysis

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The motion mechanism and characteristic of bubble in a pseudo-2D tapered fluidized bed

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Chinese Journal of Chemical Engineering 2022年第6期35卷 255-270页

作者： Wenjuan Bai Dianming Chu Kuanxin Tang Lei Geng Yan Li Yan He Shandong Engineering Laboratory for Preparation and Application of High-performance Carbon-Materials College of Electromechanical EngineeringQingdao University of Science and TechnologyShandong 266061China ShangDong Dazhan Nano Materials Co. LtdShandong 256220China

The different carbon nanotube(CNT)particles(^(@)A and^(@)V)were bed materials in the pseudo-2D tapered fluidized bed(TFB)with/without a distributor.A detailed investigation of the motion mechanism of bubbles was carried *** high-speed photography and image analysis techniques were used to study bubble characteristic and mixing behavior in the tapered angle of TFB without a *** fractal analysis method was used to analyze the degree of particles *** showed that an S-shaped motion trajectory of bubbles was captured in the bed of^(@)V *** population of observational bubbles in the bed of^(@)V particles was more than that of^(@)A particles,and the bubble size was smaller in the bed of^(@)V particles than that of^(@)A *** motion mechanism of bubbles had been shown to be related to bed materials and initial bed height in terms of analysis and comparison of bubble diameter,bubble aspect ratio and bubble shape ***,compared to the TFB with a distributor,the TFB without a distributor had been proved to be beneficial to the CNT fluidization according to the study of bubble characteristic and the degree of the particle ***,it was found that the mixing behavior of^(@)V particles was better than^(@)A particles in the tapered angle of TFB without a distributor.

关键词： Tapered fluidized bed Carbon nanotube Bubble characteristic Image processing technique fractal analysis

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Tunnel geometry of the subterranean termite Reticulitermes grassei （Isoptera： Rhinotermitidae）in response to sand bulk density and the presence of food

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Insect Science 2007年第6期14卷 511-518页

作者： TANIA NOBRE LINA NUNES DAVID E. BIGNELL Laboratorio Nacional de Engenharia Civil Nucleo de Estruturas de Madeira Lisboa Portugal Queen Mary University of London School of Biological and Chemical Sciences London UK Institute of Tropical Biology and Conservation Universiti Malaysia Sabah Kota Kinabalu Sabah Malaysia

The cryptic habits of subterranean termites restricts detailed analysis of their foraging patterns in situ, but the process is evidently dominated by tunnel constructions connecting the nest with woody resources discovered within the territory of each colony. In this study, tunnel formation and orientation were studied experimentally in the termite Reticulitermes grassei （Clement）, using 2-dimensional laboratory foraging arenas con- taining fine sand as the substratum. The building of exploratory tunnels over a 10-day period and the geometry of the resulting network are described. fractal analysis showed that tunnel geometry had a fractal dimension, regardless of the total length tunnelled whether foragers encountered the food source or not. The bulk density of the sand in the arenas affected the distances tunnelled, with higher density reducing construction, but did not affect tunnel geometry. Tunnels were not discernibly orientated with respect to the positioning of the food source, even in a situation where termites had failed to find the food source at a distance of less than 50 mm, suggesting that volatiles from wood are not attractants.

关键词： foraging gallery fractal analysis Reticulitermes grassei search pattern,subterranean termites tunnel geometry

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