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Online Degradation Detection/Prediction Method for Current Transfer Ratio of Photo-Coupler Installed in Digitally-Controlled Switching Mode Power Supply
摘要： The software-implemented degradation detection/prediction of the current transfer ratio (CTR) of a photo-coupler installed in a digitally-controlled switching mode power supply was studied. The photo-coupler is one of the key devices in an isolated power supply circuit, which transmits a voltage/current signal to a controller though the isolation gap. If the CTR of the photo-coupler degrades to halfway between the normal value and the threshold of the hardware protection circuit, overvoltage/current may be supplied continuously to the load circuit and possibly cause a severe failure. By comparing the theoretical pulse width modulation (PWM) duty, which is calculated from the input/output voltage and the pre-measured power supply circuit e?ciency, and the applied PWM duty, which is calculated via feedback control, CTR degradation is detectable online. In this paper, we describe the concept of this method and verify it using both simulation and prototyping circuits.
关键词： digitally-controlled power supply,current transfer ratio,failure prediction,degradation,photo-coupler,CTR
更新于2025-09-23 15:21:01
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Enhanced relativistic-electron beam collimation using two consecutive laser pulses
摘要： The double laser pulse approach to relativistic electron beam (ReB) collimation in solid targets has been investigated at the LULI-ELFIE facility. In this scheme two collinear laser pulses are focused onto a solid target with a given intensity ratio and time delay to generate REBs. The magnetic field generated by the first laser-driven REB is used to guide the REB generated by a second delayed laser pulse. We show how electron beam collimation can be controlled by properly adjusting the ratio of focus size and the delay time between the two pulses. We found that the maximum of electron beam collimation is clearly dependent on the laser focal spot size ratio and related to the magnetic field dynamics. Cu-Kα and ctR imaging diagnostics were implemented to evaluate the collimation effects on the respectively low energy (≤100 keV) and high energy (≥MeV) components of the REB.
关键词： relativistic electron beam,magnetic field dynamics,laser pulses,CTR imaging,Cu-Kα imaging,collimation
更新于2025-09-19 17:13:59
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A stepwise approach for the management of capsular contraction syndrome in hinge-based accommodative intraocular lenses
摘要： Purpose: The aims of this study are to define the various stages of capsular contraction syndrome (CCS) and its effect on refractive error with hinge-based accommodating intraocular lenses (IOLs) and to describe a systematic approach for the management of the different stages of CCS. Methods: Hinge-based accommodative IOLs function via flexible hinges that vault the optic forward during accommodation. However, it is the flexibility of the IOL that makes it prone to deformation in the event of CCS. The signs of CCS are identified and described as posterior capsular striae, fibrotic bands across the anterior or posterior capsule, and capsule opacification. Various degrees of CCS may affect hinge-based accommodating IOLs in a spectrum from subtle changes in IOL appearance to significant increases in refractive error and loss of uncorrected visual acuity. The signs of CCS and its effect on IOL position and the resulting changes in refractive error are matched to appropriate treatment plans. Results: A surgeon can avoid CCS and manage the condition if familiar with the early signs of CCS. If CCS is identified, yttrium–aluminum–garnet laser capsulotomy should be considered. If moderate CCS occurs, it may be effectively treated with insertion of a capsular tension ring. If CCS is allowed to progress to advanced stages, an IOL exchange may be necessary. Conclusion: Surgeons should be familiar with the stages of CCS and subsequent interventions. The steps outlined in this article help to guide surgeons in the prevention and management of CCS with hinge-based accommodative IOLs in order to provide improved refractive outcomes for patients.
关键词： CTR,z-syndrome,capsular fibrosis,pseudophakic tilt,IOL subluxation,capsular tension ring
更新于2025-09-09 09:28:46