Journal of Northeastern University(Natural Science)

Non-fragile Decentralized H_∞Control for Uncertain Singular Fractional-Order Interconnected Systems

YANG Dong-mei， SUN Yi-bing

2023, 44 (2): 153-161. DOI: 10.12068/j.issn.1005-3026.2023.02.001

Abstract ( 609 )

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The non-fragile decentralized H_∞ control problems for uncertain singular fractional-order interconnected systems with commensurate order 0<α<1 are studied. The existing criteria for admissibility and H_∞ performance of singular fractional-order linear systems are extended. And the new criteria are given in the form of strict linear matrix inequality. Based on those conclusions， through analysis of the special structure of interconnected systems， under additive and multiplicative disturbances of controller gains， sufficient conditions for the existence of non-fragile decentralized H_∞ controllers and their design methods are given by using linear matrix inequalities and matrix decomposition technology. In the design process of controllers， the interconnected matrices are not limited and strict linear matrix inequality criteria are obtained， which reduce conservatism of the systems to a certain extent. The effectiveness of the proposed methods is verified by LMI toolbox and Simulink numerical simulation.

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MPC Stability Control Method Considering the Variation of Vehicle′s Cornering Stiffness

LI Shou-tao， WEI Yu-bo， LI Qiu-yuan， YU Ding-li

2023, 44 (2): 162-167. DOI: 10.12068/j.issn.1005-3026.2023.02.002

Abstract ( 628 )

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In view of the easy steering instability of vehicles running sideways， this paper considers the variation of tire cornering stiffness to avoid saturation of tire lateral force and improve driving safety and constructs a vehicle stability control method. The front and rear axle tire sideslip angle segmented fitting method is used to establish a tire cornering stiffness fitting model， and then the fitted cornering stiffness is introduced into the vehicle dynamics model to accurately describe the current dynamic performance of the vehicle. In order to avoid the steering instability caused by the saturation of the tire lateral force， this paper proposes a vehicle stability control method based on the model predictive control(MPC)algorithm that considers the constraints of the front and rear axle tire sideslip angles to optimize the vehicle’s steering performance. Simulation results show that the proposed vehicle stability control method can suppress the tire sideslip angle of the front axles within a certain range， while taking into account the changes in the cornering stiffness， thereby avoiding the occurrence of vehicle sideslip and improving the stability performance of the vehicle.

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Research and Simulation of Space-based Resource Scheduling Based on Improved Ant Colony Algorithm

GENG Rong， ZHANG Zhao， NIU Tian-shui， WANG Yu-fei

2023, 44 (2): 168-176. DOI: 10.12068/j.issn.1005-3026.2023.02.003

Abstract ( 562 )

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The satellite resources of the space-based information network are limited.It is difficult to upgrade in orbit and the delay of inter-link communication is high， which results in inefficient processing of large-scale concurrent tasks. A dynamic priority-based task model is constructed for situations where the task is simple and concurrent and each task is handled by one node. A resource model based on fuzzy clustering theory is constructed for computing and storage resources in space-based information network. Space-based resource scheduling strategy based on improved ant colony algorithm is proposed. Load balancing factor is introduced. Pheromone update rule is changed. Task allocation strategy is adjusted. Min-Min-algorithm is combined to promote task execution and resource allocation. Simulation results show that compared with the comparison algorithm， the task completion time is 29.2% shorter， the task cumulative value is 37.9% higher， the resource load equilibrium degree is 75.5% smaller， and the resource utilization rate is 22.4% higher， which verifies the excellence of the algorithm.

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Brain MR Image Segmentation Based on Spatial Self-attention Mechanism and Depth Feature Reconstruction

WEI Ying， LIN Zi-han， QI Lin， LI Bo-qun

2023, 44 (2): 177-185. DOI: 10.12068/j.issn.1005-3026.2023.02.004

Abstract ( 584 )

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Accurate segmentation of brain tissue in MR images is a key step in clinical diagnosis， surgical planning and adjuvant treatment. Deep-learning shows great potential in various image segmentation tasks， and existing models do not have an effective way to summarize the relationship between long-distance pixels. In the network decoding stage， the features of different levels cannot be well integrated， resulting in the inability to accurately locate. To overcome the above problems， this paper proposes a brain MR image segmentation method based on spatial self-attention mechanism and depth feature reconstruction， and constructs a 2D model that can fuse 3D information， which can quickly and accurately perform dense prediction on 3D structural images. The proposed method is fully experimented on MRBrainS13 data sets and IBSR data sets， and the results show that the model outperforms the current 2D model in 3D multimodal and unimodal brain MR image segmentation， with less computing and inference time compared to the 3D model， whereas the performance is very close.

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Convergent Three-dimensional Target Matching Filtering for Ghost Imaging

ZHANG Shun-yao， SANG Ai-jun， SONG Li-jun， WANG Shi-gang

2023, 44 (2): 186-191. DOI: 10.12068/j.issn.1005-3026.2023.02.005

Abstract ( 382 )

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Aiming at the problems of low sampling frequency， low resolution and high noise in video ghost imaging reconstruction， an aggregated three-dimensional target matching filtering method was proposed. Firstly， each frame of the ghost imaging video is block-matched with the frame to be optimized and each frame of images after block matching is arranged to form a three-dimensional matrix according to the time sequence. According to the frame sequence of each frame picture， different frame weights are assigned to it. Then the matrix is subjected to three-dimensional weighted median filtering. After under-sampling simulation and experimental comparison of moving targets， the method proposed has not only lower noise figure and better structure retention， but also a better subjective evaluation compared with the existing three-dimensional filtering methods. Compared with the original experimental restoration graph， the proposed method reduces the noise figure and edge ambiguity by 34.25% and 6.86%， respectively， and the Brisque subjective evaluation was improved by 45.84%.

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SDN-based Multicast Communication Framework for Industrial Internet of Things

XU Jiu-qiang， LU Jia-xi， LI He-qun， ZHAO Hai

2023, 44 (2): 192-198. DOI: 10.12068/j.issn.1005-3026.2023.02.006

Abstract ( 477 )

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Industrial Internet of things(IIoT)must provide real-time and scalable multicast communication services. IIoT has to transmit data frames to receivers within maximal delay， and at the same time to maximize the number of applications it carries. However， among the existing multicast tree algorithms， the single-source tree algorithm only focuses on real-time performance， and the shared tree algorithm only studies to improve scalability. Algorithms that take both into account need to be further studied. Based on SDN technology， a real-time and scalable multicast communication framework for industrial Internet of things is proposed， and a multicast tree algorithm—k-DCMO is designed for it. k-DCMO algorithm constructs a shared tree with limited delay and minimum overhead for each session， which improves the scalability of multicast， and ensures the real-time performance of the session simultaneously. Experiments show k-DCMO algorithm can provide real-time support that the shared tree algorithm cannot provide， and can obtain better scalability than the single-source tree algorithm. In the experimental topology， the overhead is only 6.2% of the latter.

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Effect of Cold Rolling Deformation on Microstructure and Mechanical Properties of Solution-treated 2195 Al-Li Alloy

ZUO Yu-bo， LING Fang， HAN You， ZHU Qing-feng

2023, 44 (2): 199-205. DOI: 10.12068/j.issn.1005-3026.2023.02.007

Abstract ( 489 )

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The extruded and solution-treated plates of 2195 Al-Li alloy were cold rolled by the reduction of 5%~25% followed by an artificially aging process， and then the effect of cold rolling deformation on its microstructure and mechanical properties were studied through microstructure analysis and tensile test. The results show that the 45° shear bands begin to appear among some fibrous structures in the thickness direction of the plate after the reduction reaches 20%. Furthermore， the bands can be distributed in the whole thickness of the plate when the reduction increases to 25%. After aging treatment(155℃ for 28h)， the yield， tensile strength and final elongation of the cold-rolled plates firstly increase and then decrease with the reduction increase. When the reduction is 10%， the yield， tensile strength and final elongation of the plate reach their maximum values of 575MPa， 604MPa and 13.7%， respectively. After aging， the yield-tensile strength ratio of the sample increases from 90.8% to 97.4% with the reduction from 0 to 20%， and then slightly decreases to 97.1% with further increasing reduction to 25%. Therefore， for the extruded and solution-treated 2195 Al-Li alloy plate， the reduction of cold rolling should be controlled around 10%.

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Preparation and Mechanism of α-Fe₂O₃ Nanoparticles by Using Iron Concentrate Powder

LI Ting， PEI Wen-li， CHEN Wan-qing， TONG Bing

2023, 44 (2): 206-214. DOI: 10.12068/j.issn.1005-3026.2023.02.008

Abstract ( 447 )

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Using commercial magnetite iron powder(Fe₃O₄)， a purification and preparation process was designed， and α-Fe₂O₃ nanoparticles with a mass fraction of more than 99.5% and good dispersibility were successfully prepared. The purification， preparation process and mechanism were studied in detail. The results show that: w_NaOH has a significant impact on the effect of silicon removal， when w_NaOH is 39 %， the w_SiO▲2 in the raw ore powder can be reduced from 1.11 % to 0.032 % to get more pure iron fine powder. With the increase of the sintering temperature， the crystallization， appearance characteristics and magnetic properties of α-Fe₂O₃ particles have changed. When the sintering temperature is 670℃， the comprehensive performance of α-Fe₂O₃ particles is the best， including higher particle crystallinity， good dispersibility and ferrimagnetic properties. By controlling the heating and stirring time of the hydroxide sediment， the grain size of the α-Fe₂O₃ can be effectively regulated. When the stirring time is 60min， the α-Fe₂O₃ with a high-quality dispersability and a average particle size of only 35.3nm is obtained.

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Variation Law of Preload of Bolted Joint in Tightening Process

LUO Zhong， SHI Bao-long， ZHANG Xiao-xia， WU Fa-yong

2023, 44 (2): 215-222. DOI: 10.12068/j.issn.1005-3026.2023.02.009

Abstract ( 924 )

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Aiming at such problems as poor consistency of bolt preload in aero-engine assembly， the decline rule and distribution characteristics of bolt preload in sequential tightening and star tightening were studied based on the FEM of bolted rotors. The experimental study of bolt preload was carried out， the influence of tightening sequence and tightening speed on the bolt preload were analyzed， and then the decline mechanism of the preload over time was revealed. The results showed that the preload decreases significantly when the adjacent bolts are tightened，and increasing tightening speed will make the bolt get larger preload， which makes the connection structure more stable. After tightening the bolts， the preload will decline significantly in a short period of time， and the decline rule is closely related to the torque amplitude. Therefore， in engine assembly， the decline of preload in a short period of time cannot be ignored while strictly controlling the bolt tightening process.

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Lightweight Design Method of Girder Hoist Based on Improved Salp Swarm Algorithm

CHEN Yi-xin， ZHANG Ting， LIU Yong-gang， CHEN Jing

2023, 44 (2): 223-232. DOI: 10.12068/j.issn.1005-3026.2023.02.010

Abstract ( 380 )

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In view of the disadvantages of slow convergence， low solution accuracy and tendencies to fall into local optimal solutions in the optimization process， an improved adaptive mutation strategy of salp swarm algorithm based on Cauchy and Gaussian mixture mutation was proposed. The algorithm tend not to fall into local optimal solution by selecting the first S individuals with the best fitness value for adaptive variations， and the local search capability and convergence speed of the algorithm is improved by dynamically adjusting the size variation of the parameters through the Cauchy and Gaussian variants. Ten test functions were selected to test and compare the salp swarm algorithm and the improved adaptive mutation salp swarm algorithm respectively. Numerical analysis showed that the improved salp swarm algorithm has fast convergence speed， strong search ability and high accuracy. The improved algorithm was applied to the optimization design of the main beam structure of the beam lifter. Under the condition of meeting the design requirements of strength， stiffness and stability， etc.， the cross-sectional area of the main beam is reduced by 13.58 %， and the weight reduction effect is significant， indicating that the algorithm has good engineering application value.

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Experimental Research on Friction Reduction Characteristics and Surface Quality of 3D Ultrasonic Vibration Assisted Turning

FANG Rui， ZOU Ping， DUAN Jing-wei， WEI Shi-yu

2023, 44 (2): 233-241. DOI: 10.12068/j.issn.1005-3026.2023.02.011

Abstract ( 439 )

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To further improve the machining effect of 304 stainless steel， a theoretical model of friction reduction characteristics was established by combining the analysis of tribological dynamic loads with 3D ultrasonic vibration assisted turning. The friction reduction effect was further improved by incorporating the micro-textured tool into the model， and was verified by the experiments on the combined cutting forces of spindle speed， feed， and cutting depth. The theoretical model of surface profile formation was established by considering the relative vibration of machine tool， and the effects of cutting parameters on surface roughness were investigated by the single-factor experiments， which showed that the surface roughness gradually increased with the increase of cutting depth， spindle speed and feed rate， the surface roughness gradually increases.

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Micro-milling Force Prediction of Inconel 718 Thin-walled Parts

LU Xiao-hong， GU Han， CONG Chen， RUAN Fei-xiang

2023, 44 (2): 242-250. DOI: 10.12068/j.issn.1005-3026.2023.02.012

Abstract ( 463 )

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Inconel 718 mesoscopic thin-walled parts are in increasing demands in aerospace， medicine， communication equipment and other fields. Thin-wall micro-milling deformation is a difficult problem in the field， and micro-milling force is an important factor causing machining deformation.In order to predict the force of thin-wall micro-milling， the finite element simulation model of Inconel 718 thin-wall micro-milling process was established together with the geometric models of the micro-milling tool and thin-wall parts， the mesh division was completed， and the mesh independence was verified. The Johnson-Cook constitutive model and failure criterion were used to describe the material constitutive relationship and chip separation criterion respectively. The modified Coulomb model was used to describe the friction characteristics. The results show that the maximum and average relative errors are 11.23% and 7.04%， respectively， by comparing the micro milling force output of the simulation model with the experimental results， which verifies the effectiveness and accuracy of the model.

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Improvement of GeoSMA-3D Program Based on Multi-constrained DSI Algorithm

WANG Shu-hong， LI You-ming， YIN Hong， HOU Qin-kuan

2023, 44 (2): 251-257. DOI: 10.12068/j.issn.1005-3026.2023.02.013

Abstract ( 499 )

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Aiming at overcoming the low accuracy of traditional slope modeling， a new multi-constraint DSI fitting modeling module was established by introducing multi-constraint discrete smooth interpolation(DSI)algorithm in improving the self-developed 3D numerical analysis system GeoSMA-3D. Firstly， the original drilling and geophysical data were used to interpolate the whole slope with discrete structural plane information， then the geological objects with different characteristics were calibrated through different constraints， and then the slope body is fitted by the improved correction function. Finally， the structural plane information was obtained through the high-precision three-dimensional slope model and the clustering group was carried out. The results show that the method improves the accuracy of discrete rock mass analysis with good theoretical significance and engineering application value.

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Internal Strain Evolution Test of Cemented Backfill Based on OFDR Technology

LI Lei， HOU Chen， ZHU Wan-cheng， YANG Liu-jun

2023, 44 (2): 258-264. DOI: 10.12068/j.issn.1005-3026.2023.02.014

Abstract ( 337 )

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By using optical frequency domain reflectometer(OFDR)， a high-precision laboratory test of backfill was carried out， and the internal strain evolution law and distribution characteristics of the backfill during the early hardening process with different cement content was obtained. The results show that the internal strain evolution of the backfill is affected by the combined action of the physical sedimentation of solid particles and the chemical hydration reaction， which can be divided into four stages: physical sedimentation and stretching， hydration exothermic expansion， chemical autogenous shrinkage and basically stablestage. The internal strain distribution of the backfill mainly presents an upward convex curve in the early stage， and with the increase of curing time， it presents a multi-peak curve characteristic; OFDR technology can be used to realize high-precision distributed measurement of the internal strain of backfill and analyze the evolution characteristics of internal strain of backfill.

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Roasting and Sulfur Fixation of High-sulfur Coal Gangue by Box-Behnken Response Surface Methodology

YU Xi， LIU Wen-gang， LIU Wen-bao， PENG Xiang-yu

2023, 44 (2): 265-271. DOI: 10.12068/j.issn.1005-3026.2023.02.015

Abstract ( 465 )

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In order to achieve high-efficiency sulfur fixation in the roasting process of high-sulfur coal gangue， industrial waste boron mud was used as the sulfur fixation agent to conduct sulfur fixation experiments on coal gangue. In view of the deficiency of single factor test， the Box-Behnken response surface method was used to study the effects of sulfur fixation agent dosage， roasting temperature， roasting holding time， etc. on the sulfur fixation rate of coal gangue. The interaction between the factors was clarified. The research results show that when the mass ratio of magnesium in the sulfur-fixaing agent to the sulfur in the coal gangue is 9， with a roasting temperature of 620℃， and a roasting holding time of 100min， the sulfur-fixaing rate of the coal gangue reaches 89.35%.The most influential factor on sulfur fixation in coal gangue is the amount of sulfur fixation， followed by the roasting temperature， while the roasting holding time(within 2h)has little effect. There is a significant interaction between the roasting temperature and the amount of sulfur fixation. The optimized coal gangue sulfur fixation process can provide certain technical support for the resource utilization of high-sulfur coal gangue.

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Effect of Albite in the Flotation Separation of Serpentine and Pentlandite

HUANG Chen， LU Ji-wei， YUAN Zhi-tao， WANG Zhi-jian

2023, 44 (2): 272-278. DOI: 10.12068/j.issn.1005-3026.2023.02.016

Abstract ( 475 )

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Because serpentine is easy to form heterogeneous agglomeration with pentlandite thus affecting its flotation separation， the addition of albite was proposed to improve the flotation separation effect of pentlandite and serpentine. The influence mechanism of albite was studied. The results of flotation show that the flotation recovery of pentlandite increases from 44% to 81% after the addition of albite， which indicates that the addition of albite can weaken the heterogeneous agglomeration between serpentine and pentlandite， thus can enhance the floatability of pentlandite. The results of turbidity measurement， Zeta potential test， SEM-EDS test，adsorption capacity test and DLVO theoretical calculation show that the albite is strongly negative charged under certain pH conditions than that of the pentlandite. It is easier to form heterogeneous agglomeration between albite and serpentine， thus weakening the adhesion of serpentine on the surface of pentlandite.The research results may be used in improving the floatability of pentlandite and increasing the recovery of pentlandite， so as to effectively separate serpentine from pentlandite.

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Experimental Study on Wave Characteristics and Acoustic Emission Characteristics of Thermal Damaged Marble

JIA Peng， ZHU Peng-cheng， LI Bo， MAO Song-ze

2023, 44 (2): 279-288. DOI: 10.12068/j.issn.1005-3026.2023.02.017

Abstract ( 473 )

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The wave and acoustic emission characteristics，as well as the damage evolutions of marble from room temperature to 800℃ under uniaxial loading were studied. The results show that for heated marble， the volume increases and the mass and density decrease. 600℃ is the threshold temperature for mass and density changes. With the increase of temperature， the peak stress and elastic modulus initially increase then decrease， while the peak strain increases monotonically. With the increase of temperature， the P-wave and S-wave velocity decreases linearly， while the spectrum area， main frequency amplitude and amplitude decrease with a decreased decline rate. It is also found that there exists good consistence between the accumulated AE accounts and the stress-strain curve， which fully reflects the damage evolution law of marble in different stages. Under the effect of high temperature， the failure of marble specimen change from brittle failure to progressive failure， and the failure modes change from shear failure to splitting failure.

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Flexural Behavior and Influencing Parameters of Secant-Pipe-Roof Structure

TANG Xiu-jie， ZHAO Wen， LU Bo， LI Wei-wei

2023, 44 (2): 289-298. DOI: 10.12068/j.issn.1005-3026.2023.02.018

Abstract ( 408 )

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Based on the flexural behavior test of the secant-pipe-roof structure(SPRS)， the ABAQUS finite element software was used to establish the SPRS model. After verifying the model’s accuracy， the SPRS′s flexural behavior under loading was studied. The parameters of secant distance， steel tube diameter， steel tube thickness and steel bar diameter were selected for parameter analysis， and the flexural capacities of the structure under different parameter combinations were obtained. The results show that during the loading process， there is a significant redistribution of stress in the steel tube and the core concrete， and the SPRS has good anti-flexural behavior. The steel tube diameter is the most important factor affecting the flexural behavior of the SPRF. When the steel tube diameter is increased by 45.7%， the maximum flexural capacity of the structure can be increased by 294.3 %.

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Experimental Study on Ignition and Explosion of Carbon Material Dust

LI Gang， LIU Zong-yang， CHANG Wei-da， ZHANG Xiao-yu

2023, 44 (2): 298-304. DOI: 10.12068/j.issn.1005-3026.2023.02.019

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In order to clarify the dust explosion hazard of carbon materials， the explosiveness of 6 kinds of carbon dust materials was studied according to 3 standards. According to VDI 2263-1—1990， the low-carbon earthy graphite， the pigment carbon black and the conductive carbon black are explosive dust， low-carbon flake graphite， high-carbon flake graphite， and high-carbon earthy graphite are non-explosive dust. According to ASTM E 1226 and GB/T 16425—2018， all the 6 kinds of samples are explosive. The sensitivity characteristics of various samples were tested according to the existing test standards， the 6 types of powder dust clouds was not fired，but the dust layer of conducting charcoal black and pigment charcoal black fired at 450℃. By using the TG-DSC method ， it is found that high-carbon flake graphite， high-carbon earthy graphite and conductive carbon black experienced an oxidative exothermic reaction in the air atmosphere， with a starting temperature of 770， 680， 500℃ respectively. The explosiveness of graphite and carbon black depend on the ignition energy， and explosion will occur if it exceeds 10kJ. Although the fire sensitivity of graphite and carbon black dust is very low， there still exists fire risk.

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