This paper presents the damage characteristics of digital protective relays (DPR) in substations under high-altitude electromagnetic pulse (HEMP) environments through radiated and conducted tests. Three representative substation circuits of DPR are selected, and the radiated and conducted experiments are performed. Through a comprehensive analysis of the radiated and conducted test results, the damage characteristics of DPRs under the HEMP environment are determined, including port coupling characteristics and vulnerability, respectively.
View Article and Find Full Text PDFRev Sci Instrum
September 2024
Pulse generators with high voltage and several nanoseconds of rise time are typically used to carry out the equivalent assessment of the protection performance of typical power equipment in the high-altitude electromagnetic pulse environment. In this paper, a pulse generator with high voltage and fast rise time has been designed, and the diagnostic system with high temporal resolution has been integrated to measure the output pulse voltage of the generator. The experimental results showed that the output pulse voltage of the generator on the output load can reach 645 kV when the charged voltage of Marx generator capacitors is 40 kV.
View Article and Find Full Text PDFThe leakage field of a hybrid electromagnetic pulse simulator with horizontal polarization is simulated and experimentally investigated based on the finite integration technique in this paper. The field distribution characteristics and far-field radiation pattern of the simulator are given. The attenuation characteristics of the electric field at specific directions in the z = 2 m plane are also predicted by numerical data fitting.
View Article and Find Full Text PDFThis paper presents three methods aimed at enhancing the flashover voltage of the supporting insulator in a Tesla transformer. These methods include optimizing the maximum electric field on the insulator surface, adjusting the overall structure of the insulator, and changing the surface structure of the insulator. Ten insulator samples with different structures were designed based on electric field simulation.
View Article and Find Full Text PDFThe simulator is an indispensable device for the study of high-altitude electromagnetic pulse (HEMP) effects. In order to improve the quality of the electric field waveforms of the HEMP simulator, we carried out simulation and experimental studies for the biconical-wire grid antenna. A new bicone-wire grid antenna HEMP simulator was designed by using skeletonized cones instead of solid cones, which can substantially improve the mobility of the simulator.
View Article and Find Full Text PDFβ-Galactosidase (β-gal) is the gold standard marker of cellular senescence, which is linked with various age-related diseases. Therefore, it is essential to develop more excellent probes that can real-time monitor β-gal activity in cellular senescence . Fluorescent/photoacoustic (FL/PA) dual-modal imaging possesses excellent sensitivity and spatial resolution.
View Article and Find Full Text PDFCaspase-3 is an essential executor in apoptosis, and its activation has been regarded as a biomarker of cell apoptosis. The development of Caspase-3-responsive multimodal probes is a promising research prospect. Fluorescent/photoacoustic (FL/PA) imaging has attracted considerable attention due to the high sensitivity of FL as well as the high spatial resolution and penetration depth of PA.
View Article and Find Full Text PDFAlkaline phosphatase (ALP) is a tumor marker for early diagnosis and treatment. Tumor targeting can recognize and fight tumor cells more accurately from healthy cells. Glycyrrhetinic acid (GA) is a targeting ligand of liver tumors.
View Article and Find Full Text PDFBackground: Wheelchair part failures have doubled over the past decade. Preventative wheelchair maintenance reduces wheelchair failures and prevents user consequences. We are developing a smartphone app called WheelTrak, which alerts users when maintenance is required, to encourage maintenance practices and compliance.
View Article and Find Full Text PDFInflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder of the gastrointestinal tract with unclear etiology and insufficient therapeutic efficacy. The development of specific, effective and safe IBD treatment drugs is of great clinical significance. Curcumin (Cur) is a good candidate to prevent and manage inflammatory diseases (such as IBD) due to its antioxidant and anti-inflammatory effects with safety profile.
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