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      20 August 2020, Volume 48 Issue 8 Previous Issue    Next Issue
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    Composites Column
    Progress in 4D printing of stimulus-responsive composites and its applications
    Cheng-jun ZENG, Li-wu LIU, Wen-feng BIAN, Jin-song LENG, Yan-ju LIU
    2020, 48 (8): 1-13.   DOI: 10.11868/j.issn.1001-4381.2020.000211
    Abstract ( 1148 ( PDF (8418KB)( 692 Citation

    The stimulus-response composite is a kind of intelligent material, which usually possesses the characteristics of self-perception, autonomous response, shape memory, adaptive and self-healing. The stimulus-response materials used in 4D printing were reviewed in this paper, and the application research progress of 4D printed shape memory composite hydrogels and shape memory polymers (SMPs) and their composites was focused. Finally, the application status of 4D printing in the biomedical and aerospace fields was summarized, and the development trend and application prospect of 4D printing were prospected. 4D printing is an emerging manufacturing technology. Although various printing methods, printable smart materials and driving methods have been developed, 4D printing still faces many challenges in practical engineering applications. Novel printing technologies, smart materials, structural design and modeling software need to be developed to facilitate the practical application of 4D printing in the fields of soft robotics, biomedicine, aerospace and intelligent electronic equipment.

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    Research progress in low-density ablative materials for thermal protection system of aerospace flight vehicles
    Zhi-hai FENG, Jian-jun SHI, Lei KONG, Li-juan LUO, Xin LIANG, Song-lian KUANG
    2020, 48 (8): 14-24.   DOI: 10.11868/j.issn.1001-4381.2020.000206
    Abstract ( 1112 ( PDF (8953KB)( 544 Citation

    At present, ablation is still considered as one of the most effective, reliable, mature and economical thermal protection methods, which is widely used in thermal protection systems (TPS) of aerospace flight vehicles. Recent years, series of advanced lightweight ablative composites (LAC) were developed driven by major projects such as manned space flight, lunar exploration program, deep space exploration, and near space flight vehicles. Particularly, material's developing, engineering application and corresponding applied basic research of LACs filled in honeycombs and new LAC integrated ablation & insulation were emphatically introduced. Furthermore, complicated ablative mechanisms and synergistic effects of multiple thermal protection methods were explored. With the development of advanced TPS demand, multi-functionalization, compatibility and integration are the main development tendency of LAC for earth reentry or atmospheric entry aerospace flight vehicles.

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    Research and application progress of polymer composites in armor protection
    Hua-zhen WEI, Wei-hua ZHONG, Guang YU
    2020, 48 (8): 25-32.   DOI: 10.11868/j.issn.1001-4381.2020.000207
    Abstract ( 850 ( PDF (779KB)( 419 Citation

    Non-metallic materials such as fiber reinforced resin matrix composites with high specific strength and high specific energy absorption are the key material technologies to realize lightweight and strong protection of armor equipment. Aiming at the requirement of armored equipment protective components for high-performance ballistic materials, the technical progress, application status and development trend of polymer composite in the field of armor protection were summarized. The application of fiber reinforced resin matrix composites in composite armor, structural armor, multi-functional protective components and transparent polymer materials in transparent armor was discussed. Comparative analysis on the development and application status of high-grade organic fibers such as aramid Ⅱ, aramid Ⅲ, PBO, PIPD in China was carried out. A series of developments based on the maturity of fiber technology and different manufacturing costs, meeting the requirements of the near-term, mid-term, long-term armored equipment protection structure were proposed, and suggestions to strengthen the research on graphene ballistic materials, smart armor materials and other cutting-edge emerging protective materials and their mechanisms, and to establish and improve material evaluation methods, mechanism models and databases in the future were put forward.

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    Progress in high strength intermediate modulus carbon fiber and its high toughness resin matrix composites in China
    Jian-wen BAO, Xiang-yu ZHONG, Dai-jun ZHANG, Gong-qiu PENG, Wei-dong LI, Feng-hui SHI, Ye LI, Feng YAO, Hai-feng CHANG
    2020, 48 (8): 33-48.   DOI: 10.11868/j.issn.1001-4381.2020.000208
    Abstract ( 728 ( PDF (5901KB)( 1157 Citation

    High strength intermediate modulus carbon fiber composites are still the main aviation composites in the world at present and for a long time to come. In recent year, based on the experience of high-strength carbon fiber composites, the industrialization technology of high strength intermediate modulus T800 grade carbon fiber have been broken through in China, and the resin matrix, prepreg and manufacturing process were analysized systematically for the high toughness composites reinforced by Chinese T800 grade carbon fiber. The impact resistance of the resin matrix composites reinforced by Chinese T800H grade carbon fiber is at the same level with that of foreign composites, and the hydrothermal resistance of high toughness epoxy resin matrix composites is better than that of foreign composites with the same CAI level. At the same time, the prepreg of Chinese T800H grade carbon fiber reinforced high toughness composites has excellent process ability, and it can meet the requirements of manual-layup, ATL and AFP. Based on the T800 grade composites, the main research goal is to improve the compression mechanical properties, elastic modulus and CAI based on BVID(barely visible impact damage) for high strength intermediate modulus carbon fiber composites in the future.

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    Preparation and application of continuous fiber reinforced high-performance thermoplastic composites
    Yan ZHAO, Han-song LIU
    2020, 48 (8): 49-61.   DOI: 10.11868/j.issn.1001-4381.2019.000209
    Abstract ( 816 ( PDF (4917KB)( 418 Citation

    Continuous fiber reinforced high-performance thermoplastic composites have gradually attracted the attention of the composite industries due to their unique advantages such as light mass, high strength, good impact resistance, short molding cycle, secondary molding and waste recycling. The application status of continuous fiber reinforced high-performance thermoplastic composites was introduced in this paper starting from several kinds of high-performance thermoplastic resins. Moreover, the forming and properties of continuous fiber reinforced high-performance thermoplastic composites were also summarized in detail. At last, the future development trend of domestic continuous fiber reinforced high-performance thermoplastic composites was summarized from three aspects including application demand, molding process and material properties, in order to promote the structural design and application of continuous fiber reinforced high-performance thermoplastic composites.

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    Research progress on mechanical properties of 3D woven composites
    Li CHEN, Wei JIAO, Xin-miao WANG, Jun-ling LIU
    2020, 48 (8): 62-72.   DOI: 10.11868/j.issn.1001-4381.2020.000210
    Abstract ( 833 ( PDF (7400KB)( 429 Citation

    The three-dimensional (3D) woven composites have the advantages of strong structural design ability, overall near-net shape of complex components and high impact damage tolerance, and have become the focus of the development of new materials in the aerospace industry. In recent years, the structural design, micro-modelling and performance analysis of 3D woven composites have been rapidly developed and achieved substantial achievement. The development of multi-axial woven structures, fine modeling, and automated continuous production are the development trends of 3D woven composites. In this paper, the structural characteristics of typical 3D woven preforms were introduced. The quasi-static mechanical properties of 3D woven composites with different structures were discussed. The research progress of the micro-structure modelling, theoretical analysis and numerical simulation of 3D woven composite materials were reviewed. The typical applications of 3D woven composite materials in aerospace were listed, which can provide reference for the application research of 3D woven composite materials.

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    Research progress of precipitated phase in GH4720Li superalloy
    Jing-long QU, Chu-shan YI, Jing-wei CHEN, Yu-ting SHI, Zhong-nan BI, Jin-hui DU
    2020, 48 (8): 73-83.   DOI: 10.11868/j.issn.1001-4381.2020.000182
    Abstract ( 1028 ( PDF (4600KB)( 517 Citation

    GH4720Li superalloy has been widely employed in high-performance aero engines turbine disks and other rotating component due to the excellent high temperature strength, anti-fatigue, corrosion resistance and long-term structural stability. The mechanism of function and evolution rule of γ'phase in GH4720Li superalloy was summed up in this paper. The relationship between γ'phase and high-temperature properties and the interaction law of γ'phase and residual stress were analyzed. In addition, the research progress of the new superalloy which was designed on the basis of GH4720Li superalloy was summarized, the future application of partitioned cooling technology and dual-organization dual-performance disk preparation technology was prospected.

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    Research progress in electrochemical preparation of graphene
    Ya-hui GAO, Guo-jie YIN, Shao-wen ZHANG, Lu WANG, Qiao-jing MENG, Xin-dong LI
    2020, 48 (8): 84-100.   DOI: 10.11868/j.issn.1001-4381.2019.000704
    Abstract ( 799 ( PDF (4627KB)( 637 Citation

    The exceptional electronic, thermal, optical and mechanical properties of graphene make it ideal for the next generation of electronic and optoelectronic devices. So, it is particularly important to research and develop high-quality, large-scale and low-cost technology of graphene preparation. Electrochemical exfoliation of graphite has emerged as a promising wet chemical approach with advantages such as scalability, solution processability and eco-friendliness. In this paper, research progress of preparation of graphene by electrochemical method was reviewed. The effects of anodic oxidation and cathodic intercalation of graphite on the yield, morphology, quality and defect level of graphene were emphatically described, and the exfoliation mechanisms of the two processes were briefly summarized. Moreover, the preparation and application of functionalized graphene by electrochemical approach were introduced. Finally, it was pointed out that the future development direction of electrochemical preparation of graphene is the design of electrolyte system, optimization of exfoliation conditions, understanding of the exfoliation mechanism, rational design of electrochemical cells.

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    Research Article
    Synthesis and energy storage properties of N/O co-doped porous carbon nanoribbons
    Kan KAN, Jue WANG, Dong FU, Mei-hui SONG, Wei-jun ZHANG, Xiao-chen ZHANG
    2020, 48 (8): 101-109.   DOI: 10.11868/j.issn.1001-4381.2019.000581
    Abstract ( 623 ( PDF (4828KB)( 164 Citation

    The N/O co-doped porous carbon nanoribbons (PCNR) have been prepared via a template polymerization synchronous chemical activation route. The PCNR samples were characterized by SEM, TEM, FTIR, Raman, XRD, BET and XPS. The results show that the PCNR presents a 3D connected ribbon structure. The surface of carbon nanoribbons is porous. The PCNR800 activated at 800 ℃ presents a large specific surface area of 2342 m2/g, high-level nitrogen atom doping of 10.75% and oxygen atom doping of 13.90%. As supercapacitor electrode materials, the typical PCNR800 sample exhibits excellent energy storage characteristics. The PCNR800 supercapacitor shows a high specific capacitance of 58.8 F/g (1.0 A/g). A high energy density of 73.3 Wh/kg at a power density of 1.5 kW/kg can be achieved. The specific capacitance of the supercapacitor was 96.5% of the initial specific capacitance and the columbic efficiency still remains above 99% after 5000 cycles.

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    Synthesis and electrochemical performance of Mn2O3/Fe2O3/few layers graphene/ sulfur cathode for lithium-sulfur batteries
    Nan WANG, Xin QI, Si-kan PENG, Xiang CHEN, Chen WANG, Sheng-long DAI, Shao-jiu YAN
    2020, 48 (8): 110-118.   DOI: 10.11868/j.issn.1001-4381.2019.000246
    Abstract ( 623 ( PDF (4975KB)( 240 Citation

    Mn2O3/Fe2O3/few layer graphene/sulfur composites were prepared by melted salt method, interlayer catalytic exfoliation, annealing and melt diffusion method in sequence for lithium-sulfur batteries cathode. The three-dimensional conductive network formed by highly conductive few layers graphene provides electron transfer channel, thus promoting the high capacity performance of lithium-sulfur batteries. The metal oxides distributed uniformly on the surface of graphene exhibit strong interaction towards polysulfides, which can restrain the dissolution of polysulfides and shuttle effect and promote the cycling performance of lithium-sulfur batteries. As a result, the Mn2O3/Fe2O3/FLG30/S cathode shows high capacity and cycling performance. The cathode delivers an initial discharging capacity of 886.3 mAh·g-1 with a high capacity retention of 88.1% after 100 cycles at rate of 0.1 C.

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    Effect of Mo on corrosion resistance and magnetic property of LaFe11.5Si1.5 magnetic refrigeration materials
    Jie HU, Zhong-qi DONG, Ying-ming SHEN, Yang WANG, Jun-ya YANG
    2020, 48 (8): 119-125.   DOI: 10.11868/j.issn.1001-4381.2019.000402
    Abstract ( 653 ( PDF (4266KB)( 149 Citation

    The effect of Mo on phase formation, corrosion resistance and magnetic property of LaFe11.5Si1.5 magnetic refrigeration materials were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), electrochemical workstation and vibrating sample magnetometer (VSM). The results show that the amount of α-Fe phase and La-rich phase increases with the increase of Mo content. Mo is distributed in both NaZn13-type structure phase (1:13 phase for short) and α-Fe phase, but it does not appear in the La-rich phase. The studies on the corrosion resistance show that the corrosion potential increases and corrosion current density decreases with the increase of Mo content from x=0 to x=0.2, which indicate that the thermodynamic stability and corrosion resistance are improved. However, the corrosion resistance decreases while x increases to 0.3. The maximum magnetic entropy changes of LaFe11.5-xMoxSi1.5 under a magnetic field change of 0-3 T are about 18.51 J/(kg·K)(x=0), 16.24 J/(kg·K)(x=0.1) and 5.68 J/(kg·K)(x=0.2), respectively.

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    Effect of TiO2 particle size on microstructure and refining effect of Al-TiO2-C refiner
    Huan LIU, Rui-ying ZHANG, Jin-xuan LI, Sen YANG, Han YAN
    2020, 48 (8): 126-133.   DOI: 10.11868/j.issn.1001-4381.2019.000650
    Abstract ( 528 ( PDF (6724KB)( 130 Citation

    The Al-TiO2-C refiners were prepared by the in-situ exothermic dispersion method using Al, TiO2 and C powders. The particle sizes of TiO2 were 30, 60, 90 nm and 200 nm, respectively. The effects of particle size of TiO2 on the refiner microstructure were studied. The refinement effect on industrial pure aluminum was evaluated. The XRD, SEM and EDS techniques were used to characterize the phase composition and the microstructure of Al-TiO2-C refiners. The results show that the Al-TiO2-C refiners compose of Al3Ti, TiC and Al2O3.The particle size of TiO2 directly affects the amount, distribution and morphology of the second phase. When the particle size of TiO2 is 30-90 nm, the amount of Al3Ti and TiC is large. However, the segregation phenomenon is obviously observed. The distribution of particles is not uniform. The Al3Ti is lath-like. When the particle size of TiO2 is 200 nm, the distribution of second phases is uniform and the amount is small. The Al3Ti is blocky. After adding the Al-TiO2-C refiner prepared by 30 nm TiO2, the nucleation temperature of α-Al increases from 659.4 ℃ to 661.8 ℃.Re-heating temperature is dropped from 1.2 ℃ to 0.3 ℃.The minimum average grain size is 633 μm. The refinement effect is the best in this condition.

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    Effect of rolling mode on microstructure and plastic anisotropy of 6016 aluminum alloy sheet
    Xiao-ge DUAN, Hai-tao JIANG, Zhen-li MI, Li-li WANG, Xiao LI
    2020, 48 (8): 134-141.   DOI: 10.11868/j.issn.1001-4381.2019.000766
    Abstract ( 633 ( PDF (7141KB)( 216 Citation

    The effect of rolling mode on microstructure and plastic anisotropy of the Al-Mg-Si alloy sheets was investigated by means of earing test, X-ray diffraction (XRD) and electron backscattered diffraction (EBSD) techniques. The samples were subjected to three cold rolling modes: normal rolling (NR), transverse rolling (TR) and alternate rolling (AR) after hot rolling and annealing treatment. The results show that a strong cube {100}〈001〉 texture is formed after hot rolling and annealing treatment of the 6016 aluminum alloy. While the deformation textures significantly vary with the cold rolling modes. A strong β-fiber textures (copper, S and brass components) is dominant in NR and TR rolled sheets, the volume fraction of which is 38%-44%. In contrast, a cube component with a volume fraction of 12.2% is retained in the AR samples, and the deformation texture component is very weak. Therefore, the AR rolled sheet has the worst earing ratio of 7.1%. After the solution heat treatment, the earing ratio of AR sheets is significantly reduced to 2.76% due to the weak and random texture. While the earing ratio of NR and TR sheets is 6% and 8.16%, due to the same volume fraction of 9.12% strong cube textures. The recrystallized grain sizes of the NR, TR and AR rolled sheets are 23, 25 μm and 22 μm, and the grain distribution of the AR alloy is the most uniform. It is shown that alternate rolling can effectively improve the microstructure uniformity and plastic anisotropy of 6016 aluminum alloy recrystallization sheet.

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    Effect of annealing process on interfacial microstructure and mechanical properties of Zn/AZ31/Zn clad sheets
    Feng-guang XU, Yao LIU, Wen-jiang MA, Jing ZHANG
    2020, 48 (8): 142-148.   DOI: 10.11868/j.issn.1001-4381.2019.000456
    Abstract ( 534 ( PDF (3591KB)( 144 Citation

    Zn/AZ31/Zn clad sheets were prepared by hot rolling process. The effects of annealing temperature and time on the interface microstructure and mechanical properties of the clad sheets were investigated. The results show that the annealing temperature has great influence on the formation of interfacial diffusion layer.The interfacial diffusion layer cannot be formed at low annealing temperature, but good metallurgical bonding interface can be obtained, which is composed of Mg4Zn7 and MgZn2 phases annealed at 200 ℃. The higher annealing temperature (300 ℃) leads to the precipitation of the brittle Mg2Zn11 phase at the interface, thereby inducing microcracks along the interface. At the same annealing temperature, the extension of time only affects the thickness of the diffusion layer, and has no effect on its phase formation. The strength of the sheets is reduced after annealing, but the plasticity is improved. The clad sheets obtain better mechanical properties when annealed at 200 ℃ for 1 h.

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    Effect of Zn on interfacial microstructure and properties of steel/aluminum dissimilar metal friction stir welded joints
    Gui-yuan ZHANG, Yu-peng LI, Wen-biao GONG, Ming-yue GONG, Heng CUI
    2020, 48 (8): 149-156.   DOI: 10.11868/j.issn.1001-4381.2019.000446
    Abstract ( 605 ( PDF (7006KB)( 185 Citation

    Zn powder with a thickness of 0.4 mm was sprayed on the steel side by ion spraying method The lap welding was carried out on the 3 mm thickness 6005A-T6 aluminum alloy and 3 mm thickness S420MC steel plate using FSW (friction stir welding). The effects of Zn on the interface morphology, microstructure, mechanical properties and interfacial growth of weld were studied by means of (XRD) and microhardness of (OM), scanning electron microscope (SEM), X-ray diffractometer and microhardness. The results show that both the steel/aluminum joint without Zn layer and the steel/aluminum joint with Zn layer form the special "flying edge" of friction stir welding at the interface and extending into aluminum matrix to form the joint of mechanical occlusion, AlFe, AlFe3, Al13Fe4 intermetallic compounds are produced at the interface. Steel particles are dispersed in aluminum matrix of steel/aluminum joint without Zn layer. The maximum tensile and shear load of the joint increase from 4826 N to 5628 N at the interface. The non-Zn layer steel/aluminum fracture joint is a typical "tough-brittle" hybrid fracture, and the Zn layer steel/aluminum joint is brittle fracture. The maximum microhardness value reduces from 388HV without Zn layer joint to 210HV with Zn layer joint.

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    Preparation and properties of Ag-carrying micro-arc oxidation ceramic film on pure titanium surface
    Chun-yan DU, Hui ZHAO, Hai-tao ZHAO
    2020, 48 (8): 157-162.   DOI: 10.11868/j.issn.1001-4381.2019.000214
    Abstract ( 581 ( PDF (2265KB)( 213 Citation

    Ag-carrying micro-arc oxidation ceramic film was prepared on the surface of pure titanium by combining micro-arc oxidation and hydrothermal treatment to improve its wettability, corrosion resistance and impart antibacterial properties. The MAO film was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The hydrophilicity of the film was evaluated by contact angle test. The corrosion resistance of the film was evaluated by electrochemical test, and the antibacterial property was analyzed by the antibacterial property test. The results show that the surface morphology of Ag-carrying MAO film remains volcanic porous structure. Nano-scale Ag particles are evenly distributed around the pores. The surface of Ag-carrying MAO film is mainly TiO2 and nano-Ag particles. The hydrophilicity of the Ag-carrying MAO film is 77.0% higher than that of pure titanium, and 68.2% higher than that of MAO film. The self-corrosion potential of Ag-carrying MAO film increases by 0.44 V and 0.31 V compared with pure titanium and MAO film. The antibacterial rate of MAO film is 32.2%. The antibacterial rate of Ag-carrying micro-arc oxidation MAO film is more than 99.9% and has excellent antibacterial property.

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    Process of environmentally-friendly direct electroless nickel plating on AZ91D magnesium alloy surface
    Hui SU, Hui LIU, Chun-bo ZHANG
    2020, 48 (8): 163-168.   DOI: 10.11868/j.issn.1001-4381.2019.000977
    Abstract ( 654 ( PDF (2579KB)( 199 Citation

    In order to improve the corrosion resistance and wear resistance of magnesium alloy efficiently and environmentally, the corrosion resistant and wear resistant coating were prepared on AZ91D magnesium alloy by direct electroless nickel plating without fluorine, chromium, cyanogen and zinc. The surface morphology, composition, phase and corrosion resistance properties were characterized and compared by SEM, EDS, XRD and electrochemical workstation respectively. The results show that the coatings are smooth and compact, consisting of fine and uniform cellular structure being mainly composed of 85.25%(mass fraction) amorphous Ni and P in the ratio of main salt to reductant is 1:1.4, complexing agent concentration is 16 g·L-1, pH=7 and the temperature is (85±0.5) ℃.The hardness is increased from 72HV of substrate to 285HV. Corrosion potential is enhanced from -1.524 V(substrate) to -0.513 V, meanwhile the corrosion current density is decreased by about 3 orders of magnitude. The cohesion between the substrate and the deposition layer is good without peeling and falling off, and the thickness of the deposition layer is approximately 38 μm.

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    Error and limit determination for dimensional measurements of thin-walled structures with industrial computed tomography
    Zi-mu CHEN, Zheng-wei HU, Qian-ni WANG, Yi-wei SHI
    2020, 48 (8): 169-176.   DOI: 10.11868/j.issn.1001-4381.2019.000286
    Abstract ( 525 ( PDF (2021KB)( 147 Citation

    Due to the high-accuracy requirement of dimensional measurements for thin-walled structures of additive manufacturing products, the grayscale distribution of the industrial CT image and the location of the structural boundaries in the image space were derived. In addition, the validity of the half-height-width method and the maximum gradient method was compared and analyzed, and the limit of the dimensional measurement based on CT imaging was calculated. The thin-walled structures with different thicknesses were calibrated, and measured by industrial CT scanning and imaging experiment. The results show that the half-height-width method generates a smaller error compared with the maximum gradient method, when the thickness of the thin-walled structures is larger than the measurement limit of the CT system. Finally, the measurement limit can be obtained by numerical simulations based on the edge spread function with experimental measurements.

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