摘要：
It is crucial to correctly predict the S-matrix with plasma and set the optimal impedance matching device in the ion cyclotron resonance heating (ICRH) antenna system design. In this paper, a hybrid circuit/3DLHDAP code to verify the S-matrix measurements in the presence of plasma and optimize the load-resilient conjugate-T circuit for Large Helical Device (LHD) ICRH antennas has been developed and benchmarked. The variation of S-matrices for handshake form (HAS) and field-aligned-impedance-transforming (FAIT) antenna systems with density, magnetic field and coupling distance during heating obtained by the code's simulations agrees with that of with the LHD ICRH experiments. The mutual coupling of toroidally aligned HAS antennas is larger than that of poloidally aligned FAIT antennas over a wide range of densities. When the density and coupling distance increase, under a magnetic field on the magnetic axis of 2.75 T and 1.0 T, within a certain density change range, at the minimum voltage position with vacuum injection, the change rule of the antennas' S-a_minV_ 11 and S-a_minV_ 22 with density is opposite to that with coupling distance, which means that under certain conditions, adjusting the coupling distance may make up for the S-parameters changes caused by plasma density variation, keeping the minimum voltage position fixed, and may make impedance matching easier to achieve during long-pulse operation. Based on obtaining the S parameters, conjugate-T circuits for the HAS and FAIT antennas are designed with the hybrid circuit/3DLHDAP code, which can keep the reflection coefficients low without controlling impedance matching device over a wide range of plasma parameters region. The related results in this paper may provide some guidance for the high-power long-pulse operation of the ICRH antenna system on the fusion device.
摘要：
With the wide application of pulsed power technology in tumor ablation, sewage treatment, and other related fields, researchers have found that bipolar electrical pulses are more effective than unipolar electrical pulses. In this article, a new bipolar pulse generator is proposed, which combines the features of boost circuit and Marx circuit to significantly improve the boost ratio of output pulse and the tunability of pulse peak. In order to improve the load regulation rate and peak stability of bipolar pulse power supply, a bipolar pulse power supply based on peak closed-loop control method is designed in this article. The high-voltage pulse is attenuated, and its peak is sampled by the pulse peak sampling circuit, and the pulse peak voltage is fed back to the DSP controller for comparison with the set peak value, and the proportional integral differential (PID) adjustment is performed according to the voltage deviation, and the boost ratio of the pulse generator is changed to realize the constant peak output of the bipolar pulse. In order to verify the feasibility of the proposed bipolar pulse generator with peak closed-loop control scheme, simulation and experimental studies of the bipolar pulse power supply with five-stage peak closed-loop control were conducted. The results show that the output repetition frequency of 5 kHz, pulsewidth of 5– $10~\mu \text{s}$ , and peak pulse value within ±2.0 kV can be stabilized when the input voltage is 100 V.
通讯机构：
[Wang, Y ] U;Univ South China, Sch Elect Engn, Hunan Prov Key Lab Ultrafast Micro Nano Technol &, Hengyang 421001, Peoples R China.
摘要：
Wireless rechargeable sensor network (WRSN) uses mobile chargers (MCs) to charge sensor nodes wirelessly to solve the energy problems faced by traditional wireless sensor network. In WRSN, mobile charging schemes with multiple MCs supplementing energy are quite common. How to properly plan the MC's moving path to reduce the charge energy loss and deploy nodes to improve network coverage rate has become a huge research challenge. In this paper, a collaborative energy optimization algorithm (CEOA) is proposed for multiple chargers based on k-mean++ and node collaborative scheduling. The CEOA combines internal energy optimization and external device power supply, effectively prolongs network lifetime, and improves network coverage rate. It uses the k-mean++ to cluster nodes in the network; then, the nodes in the network are scheduled to sleep based on the confident information coverage (CIC) model. Finally, the CEOA uses a main mobile charger to carry multiple auxiliary mobile chargers to charge all the nodes in the cluster. Simulation results show that the proposed algorithm increases the network lifetime by more than 8 times and the coverage rate by about 20%.
摘要：
In practical wireless sensor networks (WSNs), cascading failures are closely related to network load distribution, which in turn strongly relies on the locations of multiple sink nodes. For such a network, understanding how the multisink placement affects its cascading robustness is essential but still largely missing in the field of complex networks. To this end, this paper puts forward an actual cascading model for WSNs based on the multisink-oriented load distribution characteristics, in which two load redistribution mechanisms (i.e., global routing and local routing) are designed to imitate the most commonly used routing schemes. On this basis, a number of topological parameters are considered to quantify the sinks' locations, and then, the relationship between these quantities with network robustness is investigated on two typical WSN topologies. Moreover, by employing the simulated annealing approach, we find the optimal multisink placement for maximizing network robustness and compare the topological quantities before and after the optimization to validate our findings. The results indicate that for the sake of enhancing the cascading robustness of a WSN, it is better to place its sinks as hubs and decentralize these sinks, which is independent of network structure and routing scheme.
作者机构：
[Liu, Yong] Univ South China, Coll Elect Engn, Hengyang 421001, Peoples R China.;[Hu, Ji-wen; Xie, Ya-qian; Liu, Yong] Univ South China, Coll Math & Phys, Hengyang 421001, Peoples R China.
会议名称：
Conference on Biophysical-Society-of-GuangDong-Province-Academic-Forum - Precise Photons and Life Health (PPLH)
会议时间：
DEC 09-11, 2022
会议地点：
Guangzhou, PEOPLES R CHINA
会议主办单位：
[Liu, Yong] Univ South China, Coll Elect Engn, Hengyang 421001, Peoples R China.^[Liu, Yong;Hu, Ji-wen;Xie, Ya-qian] Univ South China, Coll Math & Phys, Hengyang 421001, Peoples R China.
会议论文集名称：
Proceedings of SPIE
关键词：
Atherosclerosis;Electromagnetic wave;Ablation of heat;Finite element method
摘要：
The purpose of this study is to explore the thermal damage of microwave to atherosclerotic plaques in order to achieve the purpose of treating atherosclerosis. In this paper, a fluid-solid-heat coupling model of thermal ablation of atherosclerotic plaque is established (The coupling model of blood-plaque-electromagnetic wave is studied in this paper, in which the thermal ablation of atherosclerotic plaque means that the electromagnetic wave is used to generate heat, and the temperature of atherosclerotic plaque tissue rises. If the cells in it reach the threshold of death temperature, they will be killed, so as to achieve the purpose of thermal ablation.). The electromagnetic field and bio-thermal equation are solved and analyzed by finite element method. By calculating the temperature and thermal damage distribution of microwave on atherosclerotic plaque, the effect of microwave on thermal ablation of atherosclerotic plaque was evaluated. The results show that the thermal damage degree of atherosclerotic plaque is positively correlated with electromagnetic wave frequency, electromagnetic wave power and heating time. The model shows that electromagnetic wave hyperthermia may provide a new therapeutic mode for thermal ablation of atherosclerotic plaques.
摘要：
At present, system-level fault detection and diagnosis (FDD) research often uses correlation-based machine learning methods combined with multiple heterogeneous diagnosis methods to improve the fault detection rate (FDR), that is, decision-level fusion. Since it does not take into account the causal direction of the decision relationship, it will affect the realization of the fusion objectives, and lead to the reduction of the fusion range and the decrease of the global decision on FDR. In this regard, the structural causal model (SCM), a commonly used causal model in causal science, can use the causal graph to ensure causal direction of fusion, and the structural equation can be used to achieve fusion objectives to increase FDR, which can improve this problem. In this paper, we propose seven fusion objectives according to the diagnostic advantage interval of each preliminary method, and use SCM to construct causal graph and structural equation to achieve decision-level fusion according to the proposed seven fusion objectives, thereby improving FDR. The proposed method is validated through the simulation platform Tennessee Eastman process. We choose to combine the prediction results of Linear Discriminant Analysis method and Gaussian Naive Bayes method to achieve decision-level fusion. The results show that compared with the single method and the Bayesian network decision-level fusion method, the proposed method can achieve the best results in the FDR of each single system state and average FDR, and the above indicators are significantly improved.
作者机构：
[Lu, Zhendong; Luo, Xiao-Qing; Liu, Qin-Ke; Luo, XQ; Zhou, Yaojie; Wang, Xin-Lin] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Li, Yan] Univ South China, Sch Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Liu, W. M.] Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China.;[Wang, Xin-Lin] Univ South China, Sch Mech Engn, Hunan Prov Key Lab Ultrafast Micro Nano Technol &, Hengyang 421001, Peoples R China.
通讯机构：
[Luo, XQ ] U;Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
摘要：
Chiral metasurfaces, with appealing properties for studying light-matter interactions at the nanoscale, have emerged as a promising platform for the realization of chiral optical responses, thereby showing advantages in chirality-related applications. The conventional approaches primarily concentrate on circular dichroism and the high Q factor of the chiral resonances, while little attention has been paid to the aspects of flexibility and controllability in the modulation of optical chirality, further inhibiting the implementation of tunable and multifunctional chiral metadevices. Here, we employ a planar chiral silicon metasurface governed by bound states in the continuum (BICs) to unravel steerable chiral optical responses. In particular, the BIC-based intrinsic and extrinsic planar chiralities can be precisely steered by breaking the in-plane symmetry and the illumination symmetry, respectively. Moreover, a hybrid Si−VO2 metasurface, manifested by the chiral coupled-mode theory, showcases the feasibility of actively tuning the dissipative loss while maintaining chiral quasi-BICs, then yielding desired loss-steered optical chirality. Our results provide alternative insights into tunable optical chirality and pave the way for advancements in chiroptical applications.
