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| 1 | Current-limiting characteristics of saturated iron-core fault current limiters in VSC-HVDC systems based on electromagnetic energy conversion mechanism显示文摘A common method to examine the current-limiting performance of saturated iron-core fault current limiter(SI-FCL) in high-voltage direct-current transmission based on voltage source converter(VSC-HVDC) systems is to solve differential equations based on the system fault transient characteristics and the equivalent inductance calculation equation. This method analyzes the fault current of the VSC-HVDC system in the time domain. However, it is computationally complex and cannot directly reflect the relationship between parameters and the currentlimiting effect of the SI-FCL.In this paper,the relationship between the magnetic flux density and magnetic field energy of the SI-FCL is analyzed. The energy exchange between the DC capacitor and the SI-FCL in the DC short circuit fault process is analyzed. From the perspective of electromagnetic energy conversion, the criterion for determining the current-limiting ability of the SI-FCL in the transient process is given based on the parameters of the SI-FCL and VSC-HVDC system. On this basis, the characteristics of the DC side fault current and the capacitor voltage when the SI-FCL has current-limiting ability are examined.Based on the parameters of the SI-FCL and VSC-HVDC system, a method for calculating the fault current peak value and capacitor voltage drop time is given. Finally, the accuracy of the analysis of the SI-FCL in the VSC-HVDC system based on the electromagnetic energy conversion mechanism is demonstrated through a case study and simulation results of the VSC-HVDC system with different SI-FCLs. | Botong LI Hanqing CUI Fangjie JING Bin LI Yichao LIU | 2019 | Journal of Modern Power Systems and Clean Energy2019，7，2： | 7 |
| 2 | Effect of bombarding energy on ion beam assisted deposited DLC film on UHMWPE显示文摘Diamond-like carbon (DLC) films on ultra-high molecular weight polyethylene substrates were prepared at CHn+ ion bombarding energies of 200-1000eV at room temperature using ion beam assisted deposition technique. The wear tests exhibited a high wear resistance for all DLC films. X-ray photoelectron spectfoscopy and Raman spectroscopy analysis indicated that DLC film was amorphous with a characteristic high fracdion of sp3 bonds in the structure of mixed sp:2+ sp3 bonding at an optimal bombardingenergy of 600eV. | Dejun LI Hanqing GU and Fuzhai CUI(1. Department of physics, Tianjin Normal University, Tianjin 300074, P.R.China2. Institute of Urology Surgery, Tianjin 300211, P.R.China3. Department of Materials Science and Engineering, Tsinghua University, Beijing | 1998 | Chinese Journal of Biomedical Engineering(English Edition)1998，7，4： | 2 |
| 3 | Transient fault identification method for bipolar short-circuit fault on MMC‐HVDC overhead lines based on hybrid HVDC breaker显示文摘A bipolar short‐circuit transient fault identification method for overhead transmission lines in modular multi‐level converter‐based high voltage direct current(MMC‐HVDC)grid based on the hybrid HVDC breaker is proposed.The circuit breakers on both sides of the positive and negative overhead transmission lines will trip after a bipolar short‐circuit fault in the MMC‐HVDC grid.In order to identify whether the fault is a transient fault,the isolating switch of the DC breaker on one line side is reclosed first,and the voltage change on this line side in the case of transient and permanent faults is analysed.By comparing the electrical characteristics of the voltage on the line side under transient and permanent faults,a transient fault identification method is proposed,and the calculation method of the setting value of the criterion is obtained.Finally,by building the MMC‐HVDC system model for simulation in power systems computer aided design,the accuracy and effectiveness of the proposed method for transient fault identification are verified. | Botong Li Chunbo Li Bin Li Weijie Wen Hanqing Cui Jiang Su | 2021 | High Voltage2021，6，5： | 1 |
| 4 | Design and development of a mitochondrial-targeted photosensitizer for two-photon fluorescence imaging and photodynamic therapy显示文摘Mitochondria are well-acknowledged as ideal targets for tumor therapy due to their important role in energy supply and cellular signal regulation.Mitochondria-specific photosensitizers have been reported to be critical for inducing cell apoptosis.Two-photon fluorescence imaging provides a new technique for delineating biological structures and activities in deep tissues.Herein,we developed a new aggregation-induced emission(AIE)active photosensitizer by attaching a pyridinium group for mitochondrial target-ing.The rationally designed photosensitizer(TTTP)exhibited excellent photophysical properties,good biocompatibility,reactive oxygen species(ROS)stimulation ability,anticancer efficacy,and two-photon imaging properties.TTTP was highly taken up by cells and accumulated specifically in mitochondria but was selectively cytotoxic to cancer cells.Under light irradiation,the generation of ROS was significantly boosted,leading to actively induced apoptosis.The in vivo tumor photodynamic therapeutic efficacy of TTTP showed significant inhibition of tumor growth.Furthermore,the underlying mechanism of TTTP tu-mor suppression revealed that the apoptosis agonist Bax was markedly up-regulated while the antagonist Bcl-xL was down-regulated.This research provides a potential mitochondrial-targeted phototherapeutic agent for effective therapy and two-photon fluorescence imaging. | Yu Chen Sheng Zhang Tianjiao Cheng Wei Lin Linlin Mao Zhonghui Chen Yang Yang Hanqing Huang Jinqiu Li Zhiyong Ke Zhong-Kai Cui | 2023 | Journal of Materials Science & Technology2023，，10： | 0 |
| 5 | A Planar 4-Bit Reconfigurable Antenna Array Based on the Design Philosophy of Information Metasurfaces显示文摘Inspired by the design philosophy of information metasurfaces based on the digital coding concept,a planar 4-bit reconfigurable antenna array with low profile of 0.15λ0(whereλ0is the free-space wavelength)is presented.The array is based on a digital coding radiation element consisting of a 1-bit magnetoelectric(ME)dipole and a miniaturized reflection-type phase shifter(RTPS).The proposed 1-bit ME dipole can provide two digital states of'0'and'1'(with 0°and 180°phase responses)over a wide frequency band by individually exciting its two symmetrical feeding ports.The designed RTPS is able to realize a relative phase shift of 173°.By digitally quantizing its phase in the range of 157.5°,additional eight digital states at intervals of 22.5°are obtained.To achieve low sidelobe levels,a 1:16 power divider based on the Taylor line source method is employed to feed the array,A prototype of the proposed 4-bit antenna array has been fabricated and tested,and the experimental results are in good agreement with the simulations.Scanning beams within a±45°range were measured with a maximum realized gain of 13.4 dBi at12 GHz.The sidelobe and cross-polarization levels are below-14.3 and-23.0 dB,respectively.Furthermore,the beam pointing error is within 0.8°,and the 3 dB gain bandwidth of the broadside beam is 25%.Due to its outstanding performance,the array holds potential for significant applications in radar and wireless communication systems. | Zheng Xing Wang Hanqing Yang Ruiwen Shao Jun Wei Wu Guobiao Liu Feng Zhai Qiang Cheng Tie Jun Cui | 2022 | Engineering2022，，10： | 0 |
| 6 | Realizing complex beams via amplitude-phase digital coding metasurfaces and semidefinite relaxation optimization显示文摘Complex beams play important roles in wireless communications,radar,and satellites,and have attracted great interest in recent years.In light of this background,we present a fast and efficient approach to realize complex beams by using semidefinite relaxation(SDR)optimization and amplitude-phase digital coding metasurfaces.As the application examples of this approach,complex beam patterns with cosecant,flat-top,and double shapes are designed and verified using full-wave simulations and experimental measurements.The results show excellent main lobes and low-level side lobes and demonstrate the effectiveness of the approach.Compared with previous works,this approach can solve the complex beam-forming problem more rapidly and effectively.Therefore,the approach will be of great significance in the design of beam-forming systems in wireless applications. | Junwei WU Qiong HUA Hui XU Hanqing YANG Zhengxing WANG Qiang CHENG Tie Jun CUI | 2023 | Frontiers of Information Technology & Electronic Engineering2023，24，12： | 0 |
| 7 | Epidemiological Characteristics of Maize Rough Dwarf Disease in Huang-Huai-Hai Plain显示文摘Maize rough dwarf disease is a common epidemic disease in large areas.Its epidemic and occurrence mechanism is a complex process.In this paper,the epidemiological characteristics and influencing factors of maize rough dwarf disease in Huang-Huai-Hai plain were elaborated based on the research results of maize rough dwarf disease at home and abroad for many years.The epidemic of maize rough dwarf disease is affected by many factors,such as the occurrence and virus carrying rate of the first generation small brown planthopper,accumulation of virus sources on gramineous crops and weed hosts,maize variety resistance,maize sowing date,maize growth period,crop layout,tillage system,climate and ecological environment.The key factors causing the outbreak and epidemic of maize rough dwarf disease are the planting of maize susceptible varieties,the meeting of maize seedling stage and the peak period of adult spread of the first generation of small brown planthopper. | Shengji WANG Bin WU Shanshan JIANG Mei ZHANG Liping MA Tinglin SUN Hanqing CUI | 2019 | Agricultural Biotechnology2019，8，4： | 0 |
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