RESUMEN
In this paper, a passive method for the noise reduction of the PMSM (Permanent Magnet Synchronous Machine) is presented. The principle is to add an auxiliary three-phase winding into the same slots as the initial stator winding, short-circuited via three capacitors of suitable values. The aim is to create a damping effect for flux density harmonic components, especially high-frequency harmonics from the PWM (PulseWidth Modulation), in the air gap in order to reduce the noise and vibration of the PMSM. The method can significantly reduce the global sound pressure level and vibrations for specific frequencies. Because of passive features, the additional winding effectively mitigates magnetic noise without greatly increasing the complexity of design and manufacturing, which also extends its applicability to different PMSMs.
RESUMEN
Highly deformable batteries that are flexible and stretchable are important for the next-generation wearable devices. Several studies have focused on the stable operation and life span of batteries. On the other hand, there has been less focus on the packaging of highly deformable batteries. In wearable devices, solid-state or pouch lithium-ion batteries (LIBs) packaged in aluminum (Al)-laminated films, which protect against moisture and gas permeation, are used. Stretchable elastomer materials are used as the packaging films of highly deformable batteries; however, they are extremely permeable to gas and moisture. Therefore, a packaging film that provides high deformability along with gas and moisture barrier functionalities is required for the stable operation of highly deformable batteries used in ambient conditions. In this study, a stretchable packaging film with high gas barrier functionality is developed successfully by coating a thin layer of liquid metal onto a gold (Au)-deposited thermoplastic polyurethane film using the layer-by-layer method. The film exhibits excellent oxygen gas impermeability under mechanical strain and extremely low moisture permeability. It shows high impermeability along with high mechanical robustness. Using the proposed stretchable gas barrier film, a highly deformable LIB is assembled, which offers reliable operation in air. The operation of the highly deformable battery is analyzed by powering LEDs under mechanical deformations in ambient conditions. The proposed stretchable packaging film can potentially be used for the development of packaging films in advanced wearable electronic devices.
RESUMEN
When doctors use contrast-enhanced computed tomography (CECT) images to predict the metastasis of axillary lymph nodes (ALN) for breast cancer patients, the prediction performance could be degraded by subjective factors such as experience, psychological factors, and degree of fatigue. This study aims to exploit efficient deep learning schemes to predict the metastasis of ALN automatically via CECT images. A new construction called deformable sampling module (DSM) was meticulously designed as a plug-and-play sampling module in the proposed deformable attention VGG19 (DA-VGG19). A dataset of 800 samples labeled from 800 CECT images of 401 breast cancer patients retrospectively enrolled in the last three years was adopted to train, validate, and test the deep convolutional neural network models. By comparing the accuracy, positive predictive value, negative predictive value, sensitivity and specificity indices, the performance of the proposed model is analyzed in detail. The best-performing DA-VGG19 model achieved an accuracy of 0.9088, which is higher than that of other classification neural networks. As such, the proposed intelligent diagnosis algorithm can provide doctors with daily diagnostic assistance and advice and reduce the workload of doctors. The source code mentioned in this article will be released later.