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Wuyishan, China

Wuyi University is a university based in Wuyishan, Nanping county in Fujian province, China.The university was established in 1958 to offer undergraduate courses in the county. Wikipedia.

Ou J.,Wuyi University

Three graph-transformations are introduced for maximizing the total number of matchings of a graph, by which chemical trees that have maximal energy and any prescribed maximum vertex-degree are characterized. Orderings of n-vertex chemical trees are presented according to their energy, some of which contain approximate n trees. Finally, acyclic graphs with maximal energy but without perfect matchings are also characterized. Source

Due to the movement and complexity of the carbon market, traditional monoscale forecasting approaches often fail to capture its nonstationary and nonlinear properties and accurately describe its moving tendencies. In this study, a multiscale ensemble forecasting model integrating empirical mode decomposition (EMD), genetic algorithm (GA) and artificial neural network (ANN) is proposed to forecast carbon price. Firstly, the proposed model uses EMD to decompose carbon price data into several intrinsic mode functions (IMFs) and one residue. Then, the IMFs and residue are composed into a high frequency component, a low frequency component and a trend component which have similar frequency characteristics, simple components and strong regularity using the fine-to-coarse reconstruction algorithm. Finally, those three components are predicted using an ANN trained by GA, i.e., a GAANN model, and the final forecasting results can be obtained by the sum of these three forecasting results. For verification and testing, two main carbon future prices with different maturity in the European Climate Exchange (ECX) are used to test the effectiveness of the proposed multiscale ensemble forecasting model. Empirical results obtained demonstrate that the proposed multiscale ensemble forecasting model can outperform the single random walk (RW), ARIMA, ANN and GAANN models without EMD preprocessing and the ensemble ARIMA model with EMD preprocessing. © 2012 by the authors; licensee MDPI. Source

Phase adjustment is employed to redistribute the optical electric field and improve the optical absorption for semitransparent organic solar cells with one-dimensional photonic-crystals. Simulations reveal that tailoring the reflection phase shift of the one-dimensional photonic-crystals can shift the active layer into the electrical maximum region where it is most beneficial for photon absorption. With appropriate adjustment of the reflection phase shift, the optical absorption within the blue and near-infrared wavelength ranges can be improved simultaneously and yield an improvement of 112.5 in the total absorbed photons for the devices. In addition, the average transmission remains 71.1 across the visible wavelength range of 470 nm-700 nm. © 2011 American Institute of Physics. Source

A two-mode moderate microcavity (MM) structure has been constructed to confine large optical electric field in the low band gap polymer solar cells by inserting a titanium dioxide (TiO 2) layer into the devices. Simulations demonstrate the two-mode MM can significantly improve the light absorption at two discrete wavelength ranges and yield an improvement of about 13.8% in total absorbed photons (TAPs) for the device with a 60 nm thick active layer. Combined with an optical spacer, the MM structure leads to a larger improvement of 32.8% in TAPs. The efficacy of the MM structure is revealed to be strongly dependent on the active layer thickness. © 2011 American Institute of Physics. Source

Lu D.,Wuyi University
Guangxue Xuebao/Acta Optica Sinica

The three-mode squeezed vacuum state is proposed by using of a new three-mode squeezing operator acting on a three-mode vacuum state. With two of the three modes measured, the influence of the selective measurement on squeezing effect, antibunching effect and photon statistical distribution of the third mode is discussed. The results obtained show that on the one hand, if the first and the second modes are selectively measured in a two-mode squeezed state, the state vector of the third mode collapses onto single-mode squeezing state and squeezing of the third mode is strengthened. On the other hand, nonclassical properties of photon statistical distribution is strongthened by measuring the quantum state, which has no effect on antibunching of the third mode. Source

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