A new hybrid inductor-inductor-capacitor (LLC) converter is investigated to have wide voltage input operation capability and zero-voltage turn-on characteristics. The presented circuit topology can be applied for consumer power units without power factor correction or with long hold-up time requirement, photovoltaic energy conversion and renewable energy power transfer. To overcome the weakness of narrow voltage gain of resonant converter, the hybrid LLC converter with different turns ratio of transformer is presented and the experimental investigation is provided to achieve wide voltage input capability (400 V–50 V). On the input-side, the converter can operate as full bridge resonant circuit or half bridge resonant circuit with input split capacitors for high or low voltage input region. On the output-side, the less or more winding turns is selected to overcome wide voltage input operation. According to the circuit structures and transformer turns ratio, the single stage LLC converter with wide voltage input operation capability (400 V–50 V) is accomplished. The laboratory prototype has been developed and the experimental waveforms are measured and demonstrated to investigate the effectiveness of the presented hybrid LLC converter.

Thermo-mechanical fatigue (TMF) behavior of a joint between a solid oxide fuel cell glass-ceramic sealant and an interconnect steel is investigated in a reducing atmosphere (H2–7 vol% H2O) under cyclic shear and tensile loadings combined with cyclic temperature change between 40°C and 800°C. Experimental results indicate TMF life of shear specimen is increased with a decrease in the end stress applied at 800°C which dominates the shear TMF life. The accumulated duration of loading at peak temperature range (795–800°C) in TMF test is comparable with the estimated creep rupture time at 800°C for shear specimens. TMF fracture of the shear specimens mainly occurs at the interface between the glass-ceramic layer and chromia layer. For tensile specimens, TMF life is controlled by the end stresses applied at 800°C and 40°C. For tensile TMF specimens, fracture mostly takes place within the glass-ceramic layer and at the chromia/glass-ceramic interface.

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The centrifugal seal has the advantages of simple structure, long service life and the cost is far lower than the dry gas seal. But under high-speed gas conditions, the temperature of the sealing fluid rises too high and low sealing pressure. This paper studies the gas centrifugal seal with continuous injection and discharge of sealing fluid, establishes a numerical model, simulates the gas-liquid two-phase flow field and temperature field in the sealing chamber. Revealing the effects of the speed and the sealing fluid flux on the sealing performance by comparing the changes in the sealing fluid pressure, temperature, and sealing capacity under different operating conditions. And the reliability of its application to gas mechanical seals is verified through experiments. The results show that at high speeds, the pumping compression effect of the sealing fluid is enhanced, and the sealing capability is improved. Within a certain range, increasing the flux of the sealing fluid can effectively reduce the temperature and prevent the sealing fluid from vaporizing, the continuous injection and discharge structure has a significant effect.

To solve tea image classification problems, this study focuses on triplet loss convolutional neural network to classify six high-mountain oolong tea classes. In the experiment, instead of using traditional deep learning training approach for local feature of tea images, an innovative image verification approach is proposed to learn the global feature of tea images by integrating the distributed tea leaves’ features of all tea sub-images and using a majority voting mechanism to do classification. The results show that the proposed approach can work for small sample size dataset and have higher accuracy than normal transfer learning approach. The average accuracy of the proposed approach achieves 99.54%.