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Wang X.,Hangzhou Dian Zi University | Jin Z.,Hangzhou Dian Zi University
Proceedings - 2016 9th International Congress on Image and Signal Processing, BioMedical Engineering and Informatics, CISP-BMEI 2016 | Year: 2016

In many fields of MRI (Magnetic Resonance Imaging), especially in DMRI (Dynamic MRI) domain, long acquisition time often limits its clinical applications. The new online MRI technique can obviously accelerate the imaging time for DMRI based on under-sampling acquisition and sparsity performance between neighbor frames. The data acquisition of previous online MRI schemes was based on the Cartesian coordinate. Non-Cartesian sampling, such as radial sampling, can obtain higher data acquisition speed than conventional Cartesian sampling. In order to further accelerate the imaging speed for online MRI, radial under-sampling instead of Cartesian under-sampling, was proposed to shorten the data acquisition time for DMRI. However the reconstruction of non-Cartesian data is complicated and time consumed, so GPU (Graphics Processing Unit) was used to shorten the reconstruction time. In this primary study, the full sampled cardiac dataset was used as a reference dataset, radial under-sampling with 25% and 10% k-space coverage was simulated for the online imaging scheme. The results show that radial under-sampling scheme obtained higher image quality than that of Cartesian acquisition scheme, with its imaging time still satisfying online reconstruction after applying GPU acceleration. © 2016 IEEE.

Zhao C.Y.,Hangzhou Dian zi University | Zhao C.Y.,Shanxi University | Tan W.H.,Shanghai University | Xu J.R.,Hangzhou Dian zi University | Ge F.,Hangzhou Dian zi University
Journal of the Optical Society of America B: Optical Physics | Year: 2011

A nondegenerate optical parametric amplification (NOPA) system with N modes can be resolved into combinations of N degenerate parametric amplification (DOPA j, j = 1-N) systems. Based on the quantum fluctuations, we extend the method of V1 criterion for bipartite entanglement to multipartite entanglement. The entanglement characteristics for N = 2-5 are investigated, the variance V1 decreases as a function of interaction time t, the great N brings a very small variance V1. © 2011 Optical Society of America.

Chun-Lin W.,Hangzhou Dian Zi University
International Journal of Coal Preparation and Utilization | Year: 2015

Many power plants use blend coals to replace design coal for burning due to economic reasons. These blend coals are usually blended by two types of off-design coal, so there is a need to select the off-design coals and to optimize the blend ratio. In this process, an important problem is how to estimate the properties of the blend coal, especially for the softening temperature (ST) of coal ash. To deal with this issue, this article combined support vector machines (SVM) and genetic algorithms (GA) to predict coal ash's softening temperature (ST) from a given ash composition. An SVM model was built for predicting the ST of coal ash, and its parameters were optimized using GA. The SVM model was trained and verified using experimental data from 12 coal samples and subsequently was tested using data from 17 blended coal samples. The results confirmed the validity of the SVM model, which accurately predicted the ST for all these coal samples. Based on the SVM model, a coal-blending system was developed for a given 300 MW power plant boiler. The blend coals designed by this system met the firing requirements of the boiler and achieved high thermal efficiency. © 2015 © Taylor & Francis Group, LLC.

Zhang B.,Hangzhou Dian Zi University | Hu G.-S.,Hangzhou Dian Zi University | Liang D.-P.,Harbin University of Commerce | He H.,Hangzhou Dian Zi University | Tang Y.-X.,Hangzhou Dian Zi University
Gao Xiao Hua Xue Gong Cheng Xue Bao/Journal of Chemical Engineering of Chinese Universities | Year: 2013

In order to improve the synthetical properties of polylactide (PLA)/poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)), PLA/P(3HB-co-4HB)/modified kaolin nanocomposites were prepared by melt blending method. The crystallization, dynamic mechanical properties, rheological behaviors and surface structure of the composites were studied respectively with differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), rotary rheometer and scanning electron microscope (SEM). The results indicate that the cold crystallization temperature of the composites decreases gradually, which reduces by 12.5°C, and the crystallization capacity is improved. In addition, crystallinity increases from 21.65% to 35.22% with an increase of 62.68%. DMA shows that the energy storage modulus E' and glass transition temperature of the composites increase firstly and then decrease as the modified kaolin content is increased. At melting state, viscosity decreases when the sheer rate is increased, which shows that the composites are pseudoplastic fluid. When the addition of modified kaolin achieves 4%, the notched impact strength of the composites improves significantly. SEM observations show that a small amount of modified kaolin can disperse uniformly in PLA/P(3HB-co-4HB), and it can remarkably improve the toughness of the composites.

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