Optical coherence tomography angiography (OCTA) is a novel noninvasive imaging modality that allows micron-level resolution to visualize the retinal microvasculature. The retinal vessel segmentation in OCTA images is still an open problem, and especially the thin and dense structure of the capillary plexus is an important challenge of this problem. In this work, we propose a novel image magnification network (IMN) for vessel segmentation in OCTA images. Contrary to the U-Net structure with a down-sampling encoder and up-sampling decoder, the proposed IMN adopts the design of up-sampling encoding and then down-sampling decoding. This design is to capture more image details and reduce the omission of thin-and-small structures. The experimental results on three open OCTA datasets show that the proposed IMN with an average dice score of 90.2% achieves the best performance in vessel segmentation of OCTA images. Besides, we also demonstrate the superior performance of IMN in crossfield image vessel segmentation and vessel skeleton extraction.

No abstract

No abstract

No abstract

Submarine hydrothermal fluids contain substantial energy, and temperature differences with the surrounding cold seawater can provide energy for seabed observations and submarine operations. This study proposes a novel hydrothermal power generation device comprising a thermoelectric converter and an energy management system. Herein, a waterproof module with high-temperature and high-pressure resistance was designed. Heating and pressurization tests were performed to verify the structure's feasibility. The overall structure of the system based on the module was then designed, and laboratory performance tests were conducted. A computational fluid dynamics simulation was used to further analyze the heat transfer model. The simulation results are consistent with experimental data, validating the simulation model's accuracy. The new device reduces its own weight and solves low heat transfer efficiency problems. This study increases the temperature difference between the two ends of the thermoelectric generator in the thermoelectric converter by 76.2%.INDEX TERMS CFD simulation, energy conversion, heat transfer model, hydrothermal fluid, submarine energy.