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Junfeng Gao published an article in August 2017.
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(1970 - 2017)
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Article 0 Reads 1 Citation Hydrology and phosphorus transport simulation in a lowland polder by a coupled modeling system Published: 01 August 2017
Environmental Pollution, doi: 10.1016/j.envpol.2016.09.093
Modeling the rain-runoff processes and phosphorus transport processes in lowland polders is critical in finding reasonable measures to alleviate the eutrophication problem of downstream rivers and lakes. This study develops a lowland Polder Hydrology and Phosphorus modeling System (PHPS) by coupling the WALRUS-paddy model and an improved phosphorus module of a Phosphorus Dynamic model for lowland Polder systems (PDP). It considers some important hydrological characteristics, such as groundwater-unsaturated zone coupling, groundwater-surface water feedback, human-controlled irrigation and discharge, and detailed physical and biochemical cycles of phosphorus in surface water. The application of the model in the Jianwei polder shows that the simulated phosphorus matches well with the measured values. The high precision of this model combined with its low input data requirement and efficient computation make it practical and easy to the water resources management of Chinese polders. Parameter sensitivity analysis demonstrates that Kuptake, cQ2, cW1, and cQ1 exert a significant effect on the modeled results, whereas KresuspensionMax, Ksettling, and Kmineralization have little effect on the modeled total phosphorus. Among the three types of uncertainties (i.e., parameter, initial condition, and forcing uncertainties), forcing uncertainty produces the strongest effect on the simulated phosphorus. Based on the analysis result of annual phosphorus balance when considering the high import from irrigation and fertilization, lowland polder is capable of retaining phosphorus and reducing phosphorus export to surrounding aquatic ecosystems because of their special hydrological regulation regime.
PREPRINT 0 Reads 0 Citations Magic Graphene Clusters Formation in the graphene CVD growth process on Ru and Rh Published: 14 July 2017
To improve atomically controlled chemical vapor deposition (CVD) growth of graphene, understanding the evolution from various carbon species to a graphene nuclei on various catalyst surfaces is essential. Experimentally, an ultra-stable carbon cluster on Ru(0001), Rh(111) surfaces was observed, while its structure and formation process were still under highly debate. Using ab initio calculations and kinetic analyses, we disclosed a specific type of carbon clusters, composed of a C21 core and a few dangling C atoms around, were exceptional stable in the size range from 21 to 27. The most stable one of them, an isomer of C24 characterized as three dangling C atoms attached to the C21 (denoted as C21-3C), is the most promising candidate for the experimental observation. The ultra-stability of C21-3C originates from both the stable core and the appropriate passivation of dangling carbon atoms by the catalyst surface.
Article 0 Reads 1 Citation High temperature performance of SBS modified bio-asphalt Published: 01 July 2017
Construction and Building Materials, doi: 10.1016/j.conbuildmat.2017.03.103
Article 0 Reads 0 Citations Dictionary Learning for MRI Denoising based on Modified K-SVD Published: 01 May 2017
Journal of Imaging Science and Technology, doi: 10.2352/J.ImagingSci.Technol.2017.61.3.030505
Magnetic resonance imaging (MRI) is one of most powerful medical imaging tools. However, the quality is affected by the noise pollution during the acquisition and transmission. A novel method is presented for adaptively learning the sparse dictionary while simultaneously reconstructing the image from noisy image data. The method is based on a K-singular value decomposition (K-SVD) algorithm for dictionary training on overlapping image patches of the noisy image. A modified dictionary update strategy with an effective control over the self-coherence of the trained dictionary is raised during the dictionary learning. The learned dictionary is employed to achieve effective sparse representation of the corrupted image and used to remove Rician noise, which shows a good performance in both noise suppression and feature preservation. The proposed method was compared with some current MRI denoising methods and the experimental results showed that the modified dictionary learning could obtain substantial benefits in denoising performance.
PREPRINT 0 Reads 0 Citations MoS2-graphene in-plane contact for high interfacial thermal conduction Published: 23 March 2017
Recent studies showed that the in-plane and inter-plane thermal conductivities of two-dimensional (2D) MoS2 are low, posing a significant challenge in heat management in MoS2-based electronic devices. To address this challenge, we design the interfaces between MoS2 and graphene by fully utilizing graphene, a 2D material with an ultra-high thermal conduction. We first perform ab initio atomistic simulations to understand the bonding nature and structure stability of the interfaces. Our results show that the designed interfaces, which are found to be connected together by strong covalent bonds between Mo and C atoms, are energetically stable. We then perform molecular dynamics simulations to investigate the interfacial thermal conductance. It is found surprisingly that the interface thermal conductance is high, comparable to that of graphene-metal covalent-bonded interfaces. Importantly, each interfacial Mo-C bond serves as an independent thermal channel, enabling the modulation of interfacial thermal conductance by controlling Mo vacancy concentration at the interface. The present work provides a viable route for heat management in MoS2 based electronic devices.
Article 0 Reads 1 Citation Response of ecosystem services to socioeconomic development in the Yangtze River Basin, China Published: 01 January 2017
Ecological Indicators, doi: 10.1016/j.ecolind.2016.08.035