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Structural optimization design and numerical analysis of in-vessel magnetic compression coils

FUSION engineering AND DESIGN 2023年 192卷

作者： Zhang, Qinglong Rao, Bo Yang, Yong Zhang, Ming Lv, Yiliang Peng, Tao Wang, Zhijiang Pan, Yuan Huazhong Univ Sci & Technol Wuhan Natl High Magnet Field Ctr Sch Elect & Elect Engn State Key Lab Adv Electromagnet Engn & Technol Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Sch Elect & Elect Engn Int Joint Res Lab Magnet Confinement Fus & Plasma State Key Lab Adv Electromagnet Engn & Technol Wuhan 430074 Peoples R China

An FRC (field reversed configuration) device HUST-FRC (HFRC) is under construction at Huazhong University of Science and technology, and the magnetic compression experiments will be investigated. 22 compression coils installed inside the metal vacuum chamber are designed with a peak current of about 110 kA rising within 50 mu s. The coils are subjected to large electromagnetic forces during the compression process, which will challenge the structural stability of the coils. Therefore, it is necessary to estimate the structural stability of the compression coils during the compression progress. The compression process involves complex physical problems such as the coupling of circuit-electromagnetic-thermal-mechanical and non-linear contacts between adjacent coil components. It is also a challenge to calculate the coil current, electromagnetic load, and structure stress. To solve these problems, a joint analysis method is developed based on a two-dimensional (2-D) circuit-electromagneticthermal model and a three-dimensional (3-D) electromagnetic-mechanical model. The submodeling method is employed in mechanical simulations to improve the efficiency of coil optimization design. The electromagnetic and mechanical results confirm that the design of the compression coils is valid and feasible.

关键词： Magnetic compression coils Structure stability Numerical analysis Submodeling

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A Hybrid Frequency Selective Absorber With Dual-Polarized Wireless Communication and Ultra-Wideband Absorption

IEEE OPEN JOURNAL OF ANTENNAS AND PROPAGATION

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IEEE OPEN JOURNAL OF ANTENNAS AND PROPAGATION 2025年第1期6卷 110-119页

作者： Wen, Youquan Wong, Sai-Wai Ji, Chunlin Liu, Ruopeng He, Yejun Shenzhen Univ Coll Elect & Informat Engn State Key Lab Radio Frequency Heterogeneous Integr Shenzhen 518060 Peoples R China Kuang Chi Inst Adv Technol State Key Lab Metamaterial Electromagnet Modulat T Shenzhen 518000 Peoples R China

Traditional multi-layer frequency selective absorbers (FSAs) with antenna circuit suffer from inter-layer interference, which can adversely affect the in-band frequency bandwidth of wireless communication (fractional bandwidth FBW <20% in literature). In this paper, a circuit design of decoupling between FSA-layer and antenna layer is proposed to solve this problem. The hybrid FSA with antenna circuit achieves in-band wideband dual-polarized transmitting/receiving and ultra-wideband absorption of both inband and out-of-band. The two circuit layers operate independently, resolving the problems of inter-layer interference of conventional multi-layer FSA with antenna circuit. Additionally, the antenna configuration allows for excitation at the receiving end, providing broadband radiation capability without affecting in-band absorption. A prototype of the proposed structure is fabricated with a low profile of 0.22 lambda(0). Simulated and measured results demonstrate the in-band FBW of 65.06% for wireless communication (2.8-5.5 GHz which is much wider than those reported FSAs with antenna circuit e.g. FBW<20%) for two polarizations, with isolation less than -15 dB. Furthermore, the structure achieves impressive absorption performance, with radar cross-section reduction (RCSR) of 10 dB from 2.8 to 23 GHz (FBW=156.6%), and stable basic RCSR up to an oblique incidence of 30 degrees.

关键词： Absorption Antennas Reflection coefficient Reflector antennas Freeports Integrated circuit modeling Wireless communication Wideband Resistors Antenna feeds Frequency-selective-absorber radar cross section reduction ultra-wideband absorption

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Optimal operation for district cooling systems coupled with ice storage units based on the per-unit value form

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ENERGY 2024年 302卷

作者： Zhu, Peng Zheng, J. H. Li, Zhigang Wu, Q. H. Wang, Lixiao South China Univ Technol Sch Elect Power Engn Guangzhou 510640 Peoples R China Guangzhou City Univ Technol Guangzhou 510405 Peoples R China

The integration of non-dispatchable renewable resources into the power system, as part of efforts to mitigate carbon emissions and achieve carbon neutrality, presents a significant problem in maintaining the balance between generation and consumption within multi-energy complementary systems. The widespread adoption of district cooling systems (DCS) with ice storage units has proven to be a highly effective approach for enhancing flexibility by changing the operating schedule or adopting different control strategies to participate in demand response, reducing load peaks or peaking and filling to improve system economy. However, the nonlinearity and the presence of multiple variables with different orders of magnitude of the DCS model pose a significant challenge for arithmetic operations well. The present study establishes models based on per-unit value for DCS coupled with ice storage units, and employes several objective functions to validate the selection of base values, demonstrating the superiority of the calculation process for per-unit value model. Simulation results show that, the adoption of per-unit value models of DCS significantly reduce the calculation time, particularly for large systems where it would be possible to have a reduction in time-consuming by more than 68%. Additionally, this paper suggests an operational strategy for real DCS that incorporates demand response by per-unit value models, demonstrating the efficacy of the proposed approach in achieving a reduction of 11.17% in operating costs, while simultaneously enhancing flexibility to meet the load demands of multi-energy complementary systems.

关键词： Multi-energy complementary system District cooling system Per-unit model Operation strategy Demand response

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Stability and Stabilization of Sampled-Data Based LFC for Power Systems:A Data-Driven Method

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 291-293页

作者： Yu-Long Fan Chuan-Ke Zhang Yong He the School of Automation China University of Geosciences the Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems the Engineering Research Center of Intelligent Technology for Geo-Exploration Ministry of Education IEEE

Dear Editor,This letter is concerned with stability analysis and stabilization design for sampled-data based load frequency control(LFC) systems via a data-driven method. By describing the dynamic behavior of LFC systems based on a data-based representation, a stability criterion is derived to obtain the admissible maximum sampling interval(MSI) for a given controller and a design condition of the PI-type controller is further developed to meet the required MSI. Finally, the effectiveness of the proposed methods is verified by a case study.

关键词： Sampled data control systems

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Analysis and design of in-vessel magnetic compression coil system for HFRC

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FUSION engineering AND DESIGN 2023年 194卷

A field-reversed configuration (FRC) experiment facility HUST-FRC (HFRC) is being built at Huazhong University of Science and technology, where the magnetic compression of FRC will be investigated. To generate a pulsed compression magnetic field, a compression coil system is under development, consisting of in-vessel compression coils, a pulsed power supply, and feedthroughs. Energized by the pulsed power supply, a large current peaking similar to 110 kA within 50 mu s is transferred to in-vessel compression coils across the feedthroughs. This article presents the analysis and design of the compression coil system. At first, field ripple optimizations are performed to reduce the axial and toroidal ripples within 5%, resulting in an optimized coil arrangement and an improved coil conductor structure. In addition, the power supply circuits are quite complex due to the strong electromagnetic couplings among the coils and between each coil and the metal chamber wall. To rapidly and accurately design the electrical parameters of the pulsed power supply for achieving the target coil currents, a decoupled optimization method based on a circuit-electromagnetic model and a decoupled equivalent circuit model is proposed. The errors of the coil currents and the magnetic field are within 1%. Lastly, a feedthrough design and an optimized feeder scheme are proposed to achieve the structural stability of the feedthroughs since they are subjected to large electromagnetic forces.

关键词： In-vessel magnetic compression coils Pulsed power supply Feedthrough Field ripple optimization Decoupled optimization Numerical analysis

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Stability analysis of systems with time-varying delays for conservatism and complexity reduction

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SYSTEMS & CONTROL LETTERS 2024年 193卷

作者： Fan, Yu-Long Zhang, Chuan-Ke Liu, Yun-Fan He, Yong Wang, Qing-Guo China Univ Geosci Sch Automat Wuhan 430074 Peoples R China Hubei Key Lab Adv Control & Intelligent Automat Co Wuhan 430074 Peoples R China Minist Educ Engn Res Ctr Intelligent Technol Geoexplorat Wuhan 430074 Peoples R China Beijing Normal Univ BNU Zhuhai Inst Artificial Intelligence & Future Networks BNU HKBU United Int Coll Zhuhai 519087 Peoples R China

This paper is concerned with the stability analysis of systems with time-varying delays via the Lyapunov- Krasovskii functional (LKF) method. Unlike the most existing works primarily on conservatism reduction, this paper aims to establish stability criteria with less conservatism as well as low complexity, based on a relatively simple LKF with improved derivative treatments. For this purpose, a fragmented-component-based integral inequality is developed through matrix-separation and mixed estimation of the augmented integral term, which tights the estimation gap and contributes to conservatism reduction;and a novel linearized transformation method is proposed by stripping-simplification and matrix-injection, which handles nonlinear delay-itself- related terms at a low complexity cost. Then, a novel stability criterion as well as several comparative criteria are obtained for linear time-delay systems. Finally, the superiority of the proposed methods is demonstrated via two benchmark examples and a load frequency control system.

关键词： Time-delay system Time-varying delay Matrix-injection-based method Fragmented-component-based integral inequality Stability analysis

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Feasibility study of multiple-energy Bragg peak proton FLASH on a superconducting gantry with large momentum acceptance

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MEDICAL PHYSICS 2024年第3期51卷 2164-2174页

作者： Zeng, Yiling Li, Heng Wang, Wei Liu, Xu Qin, Bin Dai, Shuyang Pang, Bo Liu, Muyu Quan, Hong Yang, Kunyu Chang, Yu Yang, Zhiyong Wuhan Univ Sch Phys & Technol Dept Med Phys Wuhan Peoples R China Huazhong Univ Sci & Technol Union Hosp Tongji Med Coll Canc Ctr Wuhan Peoples R China Hubei Key Lab Precis Radiat Oncol Wuhan Peoples R China Johns Hopkins Univ Dept Radiat Oncol & Mol Radiat Sci Baltimore MD USA Huazhong Univ Sci & Technol Sch Elect & Elect Engn State Key Lab Adv Electromagnet Engn & Technol Wuhan Peoples R China Wuhan Univ Sch Math & Stat Wuhan Peoples R China Huazhong Univ Sci & Technol Union Hosp Tongji Med Coll Canc Ctr Wuhan 430022 Peoples R China

Background: While the Bragg peak proton beam (BP) is capable of superior target conformity and organs-at-risk sparing than the transmission proton beam (TB), its efficacy in FLASH-RT is hindered by both a slow energy switching process and the beam current. A universal range shifter (URS) can pull back the high-energy proton beam while preserving the beam current. Meanwhile, a superconducting gantry with large momentum acceptance (LMA-SC gantry) enables fast energy ***: This study explores the feasibility of multiple-energy BP FLASH-RT on the LMA-SC *** and Materials: A simultaneous dose and spot map optimization algorithm was developed for BP FLASH-RT treatment planning to improve the dose delivery efficiency. The URS was designed to be 0-27 cm thick, with 1 cm per step. BP plans using the URS were optimized using single-field optimization (SFO) and multiple-field optimization (MFO) for ten prostate cancer patients and ten lung cancer patients. The plan delivery parameters, dose, and dose rate metrics of BP plans were compared to those of TB plans using the parameters of the LMA-SC ***: Compared to TB plans, BP plans significantly reduced MUs by 42.7% (P < 0.001) with SFO and 33.3% (P < 0.001) with MFO for prostate cases. For lung cases, the reduction in MUs was 56.8% (P < 0.001) with SFO and 36.4% (P < 0.001) with MFO. BP plans also outperformed TB plans by reducing mean normal tissue doses. BP-SFO plans achieved a reduction of 56.7% (P < 0.001) for prostate cases and 57.7% (P < 0.001) for lung cases, while BP-MFO plans achieved a reduction of 54.2% (P < 0.001) for the prostate case and 40.0% (P < 0.001) for lung cases. For both TB and BP plans, normal tissues in prostate and lung cases received 100.0% FLASH dose rate coverage (>40 Gy/s).Conclusions: By utilizing the URS and the LMA-SC gantry, it is possible to perform multiple-energy BP FLASH-RT, resulting in better normal tissue sparing, as compared to TB plans.

关键词： Bragg peak FLASH IMPT LMA-SC gantry universal range shifter

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A mechanical reinforced and antifreezing polyacrylate hydrogel electrolyte for high-performance zinc-ion batteries

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Nano Research 2025年第1期18卷 341-350页

作者： Zili Zhang Ruolin Wang Hongfei Lu Di Zhang Yu Zhao Jing Xu Bin Sun Zhi-Min Dang Yang Jin School of Electrical and Information Engineering Zheng Zhou UniversityZhengzhou 450001China State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

The operation of aqueous zinc-ion batteries in flexible energy storage field is plagued by the uncontrollable growth of Zn-dendrite and inevitable freeze of water below 0 ℃.Therefore,it is necessary to design a hydrogel electrolyte with good mechanical property and freezing resistance to uniform the Zn-deposition and resist flexibility loss at low *** find that the mechanical property(strength and toughness)of hydrogel electrolyte has a significant impact on the suppression of dendrite growth and the uniform deposition of zinc ***,a polyacrylate hydrogel is prepared in one step by ultraviolet(UV)curing method with Zn(CF_(3)SO_(3))_(2)salt and polyvinyl alcohol(PVA)addition to increase the antifreezing ability and mechanical *** adsorption of water molecules by 2-hydroxyethyl acrylate(HEA)and PVA reduces the freezing point of the hydrogel,which is beneficial for enhancing the electrochemical stability at low *** this basis,the Zn-symmetrical battery with hydrogel electrolyte has a long lifespan of 4710 h at 0.5 mA·cm^(-2)and 0.5 mAh·cm^(-2)at room ***,the hydrogel electrolyte exhibits an outstanding stability at low temperature of^(-2)0 ℃,the lifespan of symmetrical battery reaches to 4000 h at 0.5 mA·cm^(-2)and 0.5 mAh·cm^(-2).The assembled full cell with NaV3O8·1.5H_(2)O(NVO)cathode and hydrogel electrolyte possesses a high capacity retention ratio of 77%after 10,000 cycles at^(-2)0 ℃.The flexible cell can power light-emitting diode(LED)lamp under bending,warping and cutting without liquid leakage and an electronic watch at the operating temperature of^(-2)0 ℃.

关键词： zinc ion battery hydrogel electrolyte mechanical enhancement freezing resistance

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Multiphase reaction spinning of high-temperature resistant weavable SiO_(2)-Kevlar hybrid aerogel fibers

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Nano Research 2025年第1期18卷 424-433页

作者： Yunna Chen Wenlu Zhang Qingyang Li Wenbin Li Chong He School of Textile Science and Engineering Wuhan Textile UniversityWuhan 430200China State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile UniversityWuhan 430200China

advanced aerogel fibers possess numerousadvantages amalgamating the attributes of aerogels and fibermaterials, rendering them invaluable in the realm of thermalmanagement and regulation. However, the achievement ofrobust mechanical properties and increased temperaturestability is still a major challenge for the majority of aerogelfibers. Herein, SiO_(2)-Kevlar hybrid aerogel fibers with bioniccore-shell structure were prepared by reaction spinning andweaved into fabric. Kevlar nanowires dispersion is pumpedinto a bath comprising a self-synthesized silica sol, whichfacilitates the hybridization of biphasic aerogels through thegel reaction. Precise control over the diameter (200-800 μm)and structure of the wet gel fibers was achieved throughmeticulous adjustment of the spinning solution composition and spinning parameters. Subsequent freeze-drying processfacilitates the formation of a core-shell hybrid structure, in which the SiO_(2) aerogel layer effectively encapsulate the Kevlaraerogel core fiber. Taking full advantage of the mechanical properties of the Kevlar core fiber, the resulting SiO_(2)-Kevlaraerogel fibers exhibit commendable weaving characteristics (51.8 MPa). Furthermore, SiO_(2)-Kevlar aerogel fabrics exhibitenhanced thermal insulation characteristics with a thermal conductivity of 0.037 W/(m·K). As a result of the presence ofexternal SiO_(2) aerogel layer, the overall temperature resistance performance of the SiO_(2)-Kevlar fabric reach up to 700 ℃.

关键词： aerogel fibers SiO_(2)aerogel Kevlar aerogel reaction spinning thermal protective performance

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In Situ Ceramization of Nanoscale Interface Enables Aerogel with Thermal Protection at 1950 °C

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ACS NANO 2024年第4期18卷 3520-3530页

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

Conventional carbon fiber felt-reinforced aerogel composites are often used as lightweight thermal protection systems (TPSs) for aerospace craft. However, due to their poor oxidation resistance, they have gradually failed to handle increasingly harsh thermal environments. In this work, a nanoscale composite coating interface of SiC-ZrC ceramic precursor is first constructed on the fiber surface. Subsequently, using the coated fiber felt as a three-dimensional skeleton and through polymerization-induced phase separation, an aerogel composite with excellent thermal protection in extreme thermal environments is prepared. Owing to the in situ ceramization of this nanoscale interface at ultrahigh temperatures, the back temperature of the 12 mm thick aerogel is only 147 C-degrees after exposure to an oxyacetylene flame at 1950 C-degrees for 70 s. Meanwhile, the central region of the aerogel recedes by only 7%. Not only does this work provide a way to enhance aerogels by constructing a self-ceramizable nanoscale interface it is also expected that the developed aerogel composite can be applied in the ultrahigh-temperature thermal protection of future aerospace craft.

关键词： aerogel thermalinsulation ablation ceramization ceramicprecursor carbon fiber felt

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