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Nano Co-Continuous Structure Poly(imide-siloxane)/Phenolic Hybrid Resin Fabricated by Copolymerization for the Thermal Protection System

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INDUSTRIAL & engineering CHEMISTRY RESEARCH 2023年第27期62卷 10477-10486页

作者： Yuan, Quan Wang, Yuan Huang, Yisen Tian, Jinfeng Heng, Zhengguang Liang, Mei Chen, Yang Zou, Huawei Sichuan Univ State Key Lab Polymer Mat Engn Polymer Res Inst Chengdu 610065 Peoples R China

Organic-inorganic hybridizationis an importantway to improvethe ablation resistance of phenolic resin (PR). However, it is difficultto form a continuous inorganic liquid film on the resin surface duringablation, thus limiting the further improvement of ablation *** this work, a new poly(imide-siloxane) (PIS) was designed by introducingimide rings and terminal ethoxy groups into the main chain of silicone,and then it was introduced into PR. The imide rings can increase thepolarity of the chain, and the terminal ethoxy groups can react withhydroxyl groups in PR, which can improve the compatibility of PISwith PR. SEM and AFM showed that nano co-continuous and sea-islandstructures of hybrid resins were prepared, respectively. Then, theinfluence of different structures on thermal stability and ablation-resistantproperties was investigated by using TGA, tube furnace heat treatment,and oxyacetylene ablation test. Compared to the sea-island structure,the nano co-continuous structure of resin can form a continuous anddense SiO2 film in situ, giving the resin superior thermalstability and ablation-resistant properties. The present work providesan available way to manipulate hybrid resin's phase structureand develop high-performance ablation-resistant resin in aerospaceapplications.

关键词： Ablation Chemical structure Layers Organic polymers Polyimides

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Surface melt nitriding and strengthening mechanism of plasma torched M50 bearing steel

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JOURNAL OF MANUFACTURING PROCESSES 2024年 124卷 1214-1226页

作者： Zhang, Hainan Yu, Jianbo Yang, Zhigang Zhang, Xiaoxin Dong, Ying Jiang, Jintao Wang, Jiang Ren, Zhongming Shanghai Univ Sch Mat Sci & Engn State Key Lab Adv Special Steel Shanghai 200444 Peoples R China Shijiazhuang Tiedao Univ Engn Res Ctr Matamat & Microdevices Sch Mat Sci & Engn Shijiazhuang 050043 Peoples R China

This paper presents a new plasma torch nitriding technology for the first time to realize the surface nitriding of bearing steel for strengthening. By adjusting the plasma torch current parameters in the range of 120-160 A, M50 bearing steel was carried out at a nitriding speed of 2 s/cm(2). After nitriding, the nitrogen content was increased from 0.00732 wt% in the original M50 steel up to 0.416 wt%, and the thickness of the nitrided layer was up to 2.51 mm. FeN0.076, Fe2N and Fe3N phases were formed in the steel, which was beneficial to increase the hardness and strength of bearing steel. The Vickers hardness of the original M50 bearing steel was 241 HV0.2. However, the highest surface hardness of specimen after nitriding was increased up to 778 HV0.2, which was attributed to the effect of sub-surface hardness strengthening within 2 mm from the depth of nitride surface. The average wear coefficient and the volumetric wear rate of the specimen after nitriding were decreased by about 32 % and 70 %, respectively. TEM observation showed that after nitriding, the structure of nitrided layer was martensite. The precipitates in the steel changed from large-sized, irregular and aggregated carbides (M23C6, M4C3 and M2C) to small-sized, spherical and uniformly distributed carbon-nitrogen composite precipitates (M-23(C, N)(6), M-7(C, N)(3)) in the steel sub-surface, but no obvious precipitates were formed on the surface of nitrided specimens. At depths of 1 mm and 2 mm, the size of the precipitates was reduced by about 68 % and 41 %, respectively, and the area of the precipitates was reduced from 18.4 % to 2.3 % and 3.7 %, respectively, compared to the original M50 bearing steel. It was concluded that the nitrided layer were strengthened synergistically with nitrogen solid solution, nitrogen-containing precipitates and martensite.

关键词： Plasma torch M50 bearing steel Nitriding Properties Precipitates Microstructure

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Using multi-scale interaction mechanisms in yolk-shell structured C/Co composite materials for electromagnetic wave absorption

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材料科学技术（英文版） 2025年第12期215卷 36-44页

作者： Jintang Zhou Kexin Zou Jiaqi Tao Jun Liu Yijie Liu Lvtong Duan Zhenyu Cheng Borui Zha Zhengjun Yao Guiyu Peng Xuewei Tao Hexia Huang Yao Ma Peijiang Liu Key Laboratory of Material Preparation and Protection for Harsh Environment Ministry of Industry and Information TechnologyCollege of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing211100China Yuxi Research Institute Yuxi Industries GroupChina North Industries CroupNanyang473000China School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing211167China Key Laboratory of Material Preparation and Protection for Harsh Environment Ministry of Industry and Information TechnologyCollege of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing211100China College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing210016China National Key Laboratory on Electromagnetic Environmental Effects and Electro-optical Engineering Army Engineering UniversityNanjing210007China Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory the 5th Electronics Research Institute of the Ministry of Industry and Information TechnologyGuangzhou511370China

advanced chemical engineering for simultaneous modulation of nanomaterial morphology,defects,inter-faces,and structure to enhance electromagnetic and microwave absorption(MA)***,accurately distinguishing the MA contributions of different scale factors and tuning the optimal com-bined effects remains a formidable *** study employs a synergistic approach combining tem-plate protection etching and vacuum annealing to construct a controlled system of micrometer-sized cav-ities and amorphous carbon matrices in metal-organic framework(MOF)*** results demon-strate that the spatial effects introduced by the hollow structure enhance dielectric loss but significantly weaken impedance *** increasing the proportion of amorphous carbon,the balance between electromagnetic loss and impedance matching can be effectively ***,in a suitable graphitization environment,the presence of oxygen vacancies in amorphous carbon can induce signif-icant polarization to compensate for the reduced conductivity loss due to the absence of sp2 *** the synergistic effects of morphology and composition,the samples exhibit a broader absorp-tion bandwidth(6.28 GHz)and stronger reflection loss(-61.64 dB)compared to the original *** conclusion,this study aims to elucidate the multiscale impacts of macroscopic micro-nano structure and microscopic defect engineering,providing valuable insights for future research in this field.

关键词： MOFs Multi-scale regulation Yolk-shell structure Amorphous carbon Oxygen vacancy Microwave absorption

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Effect of initial microstructure on microstructure evolution and mechanical properties of 0.12C martensitic steels during quenching and tempering

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Journal of Iron and Steel Research International 2025年第1期32卷 260-269页

作者： Ya-ru Wang Zi-yong Hou He Yang Jun Zhao Zhi-yuan Chang Fan-mao Meng Ling Zhang Gui-lin Wu Xiao-xu Huang State Key Laboratory of Vanadium and Titanium Resource Comprehensive Utilization Panzhihua 617000SichuanChina State Key Laboratory of Advanced Special Steel Shanghai Key Laboratory of Advanced FerrometallurgySchool of Materials Science and EngineeringShanghai UniversityShanghai 200444China International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Institute of Steel Technology for Automobile and Household Appliance Pangang Group Co.Ltd.Panzhihua 617000SichuanChina ATB Motor(Shanghai)Co. Ltd.Keen International CenterShanghai 200041China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China

The microstructure evolution and mechanical properties of a Fe-0.12C-0.2Si-1.6Mn-0.3Cr-0.0025B(wt.%)steel with different initial microstructures,i.e.,hot rolled(HR)and cold rolled-annealed(CRA),were studied through optical microscopy,scanning electron microscopy,electron channeling contrast imaging,microhardness and room temperature uniaxial tensile *** water quenching from 930℃ to room temperature,a fully martensitic microstructure was obtained in both as-quenched HR and CRA specimens,which shows a microhardness of 480±5 HV,and no significant difference in microstructure and microhardness was *** test results show that the product of tensile strength and total elongation(UTS×TE)of the as-quenched HR specimen,i.e.,24.1 GPa%,is higher than that of the as-quenched CRA specimen,i.e.,18.9 GPa%.While,after being tempered at 300℃,the martensitic microstructures and mechanical properties of the two as-quenched specimens change significantly due to the synergy role of the matrix phase softening and the precipitation *** the maximum UTS×TE,it is 18.9 GPa%obtained in the as-quenched CRA one,while that is 24.4 GPa%obtained in the HR specimen after tempered at 300℃ for 5 min.

关键词： Initial microstructure Lath martensite Quenching Tempering Mechanical property

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Conditional differential analysis on the KATAN ciphers based on deep learning

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IET INFORMATION SECURITY 2023年第3期17卷 347-359页

作者： Lin, Dongdong Li, Manman Hou, Zezhou Chen, Shaozhen Informat Engn Univ Zhengzhou Peoples R China State Key Lab Cryptol Beijing Peoples R China

KATAN ciphers are block ciphers using non-linear feedback shift registers. In this study, the authors improve the results of conditional differential analysis on KATAN by using deep learning. Multi-differential neural distinguishers are built to improve the accuracy of the neural distinguishers and increase the number of its rounds. Moreover, a conditional differential analysis framework is proposed based on deep learning with the multi-differential neural distinguishers, resulting in a significant improvement than the previous. We present a practical key recovery attack on the 97-round KATAN32 with 2(15.5) data complexity and 2(20.5) time complexity. The attack of the 82-round KATAN48 and 70-round KATAN64 are also presented as the best known practical results.

关键词： block cipher conditional differential analysis deep learning KATAN family neural network

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Bursting core-localized ellipticity-induced Alfvén eigenmodes driven by energetic electrons during EAST ohmic discharges

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NUCLEAR FUSION 2024年第3期64卷 036019-036019页

作者： Su, P. Lan, H. Zhou, C. Bao, J. Liu, A. Zhu, X. Wu, M. Luo, C. Han, J. Wang, J. Liu, H. Zhang, T. Zhou, R. Lin, S. Zhao, H. Sun, Y. Qiu, Z. Chu, N. Tang, T. Tan, Y. Zeng, L. Gao, Z. Tsinghua Univ Dept Engn Phys Beijing 100190 Peoples R China Southwest Jiaotong Univ Sch Phys Sci & Technol Inst Fus Sci Chengdu 610031 Peoples R China Univ Sci & Technol China Sch Nucl Sci & Technol Hefei 230026 Peoples R China Chinese Acad Sci Inst Phys Beijing 100190 Peoples R China Shenzhen Univ Adv Energy Res Ctr Shenzhen 518060 Peoples R China Chinese Acad Sci Inst Plasma Phys Hefei 230031 Peoples R China Univ Tokyo Grad Sch Frontier Sci Kashiwa Chiba 2778561 Japan Natl Inst Fus Sci Natl Inst Nat Sci Toki 5095292 Japan Zhejiang Univ Inst Fus Theory & Simulat Sch Phys Hangzhou 310027 Peoples R China

A series of high-frequency ( 400 similar to 1000 kHz ) bursting core-localized Alfven instabilities have been observed during ohmic discharges in EAST tokamak. The instability trigger favours the discharge conditions of low toroidal magnetic field and low electron density. The toroidal mode numbers are mainly n=2 similar to 3 and they propagate in the ion diamagnetic drift (co-current) direction. These modes are radially localized in the range of rho tor=0.2 similar to 0.35 based on Doppler BackScatter measurement. They are identified as ellipticity-induced Alfven eigenmodes (EAEs) occurring at q=1 rational surfaces by magnetohydrodynamics simulations using the realistic geometry and plasma profiles. The EAEs show regular bursts with similar to 10 ms duration along with the mode frequency chirping downwards and upwards rapidly. It is also found that sawtooth events can interrupt the growth and evolution of the EAEs, causing the modes to disappear immediately. Passing energetic electrons (EEs) that move much faster than Alfven velocity are responsible for the destabilization of these EAEs, which attribute to the fact that the large poloidal and toroidal frequencies mostly cancel each other and satisfy the EAE resonance condition with primary energy exchange. These novel experimental results of the wave-particle interaction between EAEs and EEs are helpful for extrapolating alpha particle physics that are characterized by small orbit width with respect to machine size in future fusion reactors.

关键词： ellipticity-induced Alfven eigenmodes energetic electrons wave-particle interaction EAST tokamak

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A weighted matching scheme of magnetic coil design for FRC shaping control

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PLASMA PHYSICS AND CONTROLLED FUSION 2025年第1期67卷 015021-015021页

作者： Qu, Zitong Zhu, Ping Chen, Zhipeng Li, Haolong Liu, Jiaxing Huazhong Univ Sci & Technol Sch Elect & Elect Engn State Key Lab Adv Electromagnet Technol Int Joint Res Lab Magnet Confinement Fus & Plasma Wuhan 430074 Peoples R China Univ Wisconsin Madison Dept Nucl Engn & Engn Phys Madison WI 53706 USA Shenzhen Univ Coll Phys & Optoelect Engn Shenzhen 518060 Peoples R China

The two-dimensional (2D) separatrix shaping plays a crucial role in the confinement of the field-reversed configuration (FRC), and the magnetic coils serve as an effective means for its control. In this work we develop a weighted matching method to obtain an MHD equilibrium that accurately corresponds to the shape of target separatrix. By iteratively calculating the coil currents, the plasma current, and the equilibrium magnetic flux, the equilibrium separatrix progressively converges towards the desired shape. The coil currents are determined through a matching method, and the NIMEQ code is employed to compute the FRC equilibrium with a rigid rotor model of plasma distribution. This approach enables the adaption of the equilibrium separatrix into any desired shape, thus offering a potential scheme for the design and control of the 2D shaping of FRC plasma.

关键词： field reversed configuration shaping control toroidal equilibrium weighted matching method

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Power Transfer Control Strategy Based on True Bipolar MMC-MTDC System

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ENERGIES 2021年第24期14卷 8306-8306页

作者： Ding, Can Tian, Xiaojian Nie, Taiping Yuan, Zhao China Three Gorges Univ Coll Elect Engn & New Energy Yichang 443002 Peoples R China Huazhong Univ Sci & Technol State Key Lab Adv Electromagnet Engn & Technol Sch Elect & Elect Engn Wuhan 430074 Peoples R China

The true bipolar modular multilevel converter-based multi-terminal direct current (MMC-MTDC) DC transmission line is prone to single-pole grounding fault, which may cause overload and overcurrent of the non-fault DC line with fault poles, resulting in system protection misoperation and system collapse. Therefore, the power transfer control strategy should be adopted to improve system stability. In addition, considering that the commutator stations of true bipolar MMC-MTDC system may have unipolar faults, it is necessary to adopt the control strategy of inter-pole power transfer or inter-station power transfer to improve the transmission capacity of the system under fault conditions. In this paper, a power transfer control strategy is proposed, which is widely applicable to MMC-MTDC system. In the case of line fault, the power transfer takes into account the line power margin and the power margin of converter station. The inter-pole power transfer is better than the inter-station power transfer under the converter station fault condition, and the inter-station power transfer takes into account the priority of the power margin of the converter station. At the same time, based on the Zhangbei four-terminal flexible direct current transmission project, the Zhangbei four-terminal flexible direct current transmission system is built by using PSCAD/EMTDC, and the flexibility and effectiveness of the proposed strategy are verified by simulation.

关键词： true bipolar flexible direct current transmission power transfer

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Design and construction for theory and method of magnetic-controlled negative pressure GTAW arc model based on multi-physics simulation

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INTERNATIONAL JOURNAL OF advanced MANUFACTURING technology 2024年第3-4期132卷 1855-1868页

作者： Xu, Kefeng Luo, Jian Cui, Kunyu Cheng, Riping Ling, Lei Shanghai Univ Engn Sci Sch Mat Sci & Engn Shanghai 201620 Peoples R China

The two-dimensional GTAW arc model is insufficient to fully explain the effects of the external longitudinal magnetic field on the arc. Therefore, a three-dimensional GTAW arc model was established to elucidate the recirculation flow and negative pressure arc characteristic of magnetic-controlled arc. The external magnetic field controls the surface temperature, pressure, and current density distribution of the workpiece by controlling the flow of arc plasma. When the magnetic flux density is 0.04T, the surface temperature, pressure, and current density of the workpiece exhibit a bimodal distribution. Under the negative pressure of the GTAW arc, the arc plasma on both sides flowed counterclockwise around the center in the spiral upward direction and then counterclockwise downward from 0.9 mm below the tungsten electrode. By controlling the welding current and magnetic flux density, the occurrence of negative surface pressure on the workpiece can be effectively controlled.

关键词： Magnetic-controlled GTAW Negative pressure arc Recirculation flow Critical conditions Arc design Multi-physics simulation

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Unsteady hydrodynamic characteristics control of turbine blades by the vortex generators

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OCEAN engineering 2025年 324卷

作者： Jia, Guotao Chen, Cong Wang, Lu Wang, Pengzhong Huang, Bin Wu, Rui Zhejiang Univ Ocean Coll Zhoushan 316021 Peoples R China China State Shipbldg Corp Ltd Kunming Branch Res Inst 705 Kunming 650032 Peoples R China Wuhan Second Ship Design & Res Inst Wuhan 430064 Peoples R China Zhejiang Univ Ocean Res Ctr Zhoushan Zhoushan 316021 Peoples R China Zhejiang Univ Coll Energy Engn Hangzhou 310027 Peoples R China Shanghai Ship & Shipping Res Inst Shanghai 200135 Peoples R China

The horizontal axis tidal turbines (HATT) are subject to the intricacies of the marine environment, which includes the impact of large waves, high-intensity turbulence, and shear flow. These elements contribute to the unsteady hydrodynamic characteristics of the turbine blades, manifesting as load fluctuations, stall delays, and dynamic stalls. As a result, the HATT experiences severe power fluctuations, which diminish the quality of power generation and directly affect the reliability of the power grid and transmission system. Moreover, these fluctuations induce significant fatigue loads that impact various structures and components of the HATT, thereby reducing its service life and reliability. Controlling the unsteady hydrodynamic characteristics of the blades is crucial for enhancing the lifespan and operational stability of the turbine. In light of these challenges, the present study employs large eddy simulation (LES) numerical simulation techniques to delve into the unsteady hydrodynamic characteristics of HATT blades affected by turbulent flow, with a focus on the control exerted by vortex generators (VGs). The study scrutinizes how VGs manage flow separation on the blade surface under unstable inflow conditions and compares this to the hydrodynamic performance fluctuations observed with smooth blades. The findings reveal that VGs are capable of significantly reducing the unsteady hydrodynamic fluctuations on HATT blades and the associated flow separation on blade surfaces. When compared to smooth blades, the average fluctuation of the power coefficient for blades equipped with VGs has been diminished by 26.7%, the average fluctuation of the thrust coefficient has been reduced by 43.95%, and the average fluctuation of the blade root bending moment coefficient has been decreased by 26.6%. Additionally, the implementation of VGs has led to an average increase in the power coefficient of the blades by 5.8% at a tip-speed ratio of 2 and by 9.8% at a tip-speed ra

关键词： Unsteady hydrodynamic characteristics Large eddy simulation Turbulence Horizontal axis tidal turbine Vortex generators Strip method

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