Simulation research on dynamic performance of the new type high-pressure solenoid valve

To improve energy density, the transportation, storage, and operations of hydrogen, methane, and compressed air vehicles currently require high-pressure compression. High-pressure solenoid valve becomes the vital element to above system. In order to reduce leakage and aerodynamic force influence, a new type high-pressure solenoid valve was proposed. The simulation model which included electromagnetic model, aerodynamic force model was established by means of the nonlinear mathematic models. Using the software MATLAB/Simulink for simulation, the dynamic response characteristics of high-pressure pneumatic solenoid valve were obtained under different pulse width modulation (PWM) input control signals. Results show that, first of all, the new type of high-pressure solenoid valve can meet the switch requirement. Secondly, the opening movement and closing movement of the spool lags the PWM rising signal, and the coil current fluctuates significantly during the movement of the spool. Lastly, on/off status of high-pressure valve cannot be represented by the duty cycle. This research can be referred in the design of the high-pressure solenoid valve.

Cooperative Spectrum Sensing

Non

Saliency Based Opportunitstic Search for Object Part Extraction and Labeling

We study the task of object part extraction and labeling, which seeks to understand objects beyond simply identifiying their bounding boxes. We start from bottom-up segmentation of images and search for correspondences between object parts in a few shape models and segments in images. Segments comprising different object parts in the image are usually not equally salient due to uneven contrast, illumination conditions, clutter, occlusion and pose changes. Moreover, object parts may have different scales and some parts are only distinctive and recognizable in a large scale. Therefore, we utilize a multi-scale shape representation of objects and their parts, figural contextual information of the whole object and semantic contextual information for parts. Instead of searching over a large segmentation space, we present a saliency based opportunistic search framework to explore bottom-up segmentation by gradually expanding and bounding the search domain.We tested our approach on a challenging statue face dataset and 3 human face datasets. Results show that our approach significantly outperforms Active Shape Models using far fewer exemplars. Our framework can be applied to other object categories

Genome-wide analysis and identification of microRNAs in Medicago truncatula under aluminum stress

Numerous studies have shown that plant microRNAs (miRNAs) play key roles in plant growth and development, as well as in response to biotic and abiotic stresses; however, the role of miRNA in legumes under aluminum (Al) stress have rarely been reported. Therefore, here, we aimed to investigate the role of miRNAs in and their mechanism of Al tolerance in legumes. To this end, we sequenced a 12-strand-specific library of Medicago truncatula under Al stress. A total of 195.80 M clean reads were obtained, and 876 miRNAs were identified, of which, 673 were known miRNAs and 203 were unknown. A total of 55 miRNAs and their corresponding 2,502 target genes were differentially expressed at various time points during Al stress. Further analysis revealed that mtr-miR156g-3p was the only miRNA that was significantly upregulated at all time points under Al stress and could directly regulate the expression of genes associated with root cell growth. Three miRNAs, novel_miR_135, novel_miR_182, and novel_miR_36, simultaneously regulated the expression of four Al-tolerant transcription factors, GRAS, MYB, WRKY, and bHLH, at an early stage of Al stress, indicating a response to Al stress. In addition, legume-specific miR2119 and miR5213 were involved in the tolerance mechanism to Al stress by regulating F-box proteins that have protective effects against stress. Our results contribute to an improved understanding of the role of miRNAs in Al stress in legumes and provide a basis for studying the molecular mechanisms of Al stress regulation