基于纳米压缩跨平台高负载手游的技术开发

现如今，智能手机的使用非常普遍，3G和4G网络也大规模的发展和普及，手机游戏市场随之在不断扩大，手机游戏用户也在日渐增多。因此,研究适于手机平台的网游服务端关键技术具有很重要的现实意义和应用价值。     

Material constraints related to storage of future European renewable electricity surpluses with CO2 methanation

The main challenges associated with a growing production of renewable electricity are intermittency and dispersion. Intermittency generates spikes in production, which need to be curtailed when exceeding consumption. Dispersion means electricity has to be transported over long distances between production and consumption sites. In the Directive 2009/28/EC, the European Commission recommends sustainable and effective measures to prevent curtailments and facilitate transportation of renewable electricity. This article explores the material constraints of storing and transporting surplus renewable electricity by conversion into synthetic methane. Europe is considered for its mix of energy technologies, data availability and multiple energy pathways to 2050. Results show that the requirements for key materials and land remain relatively low, respecting the recommendations of the EU Commission. By 2050, more than 6 million tons of carbon dioxide might be transformed into methane annually within the EU. The efficiency of renewable power methane production is also compared to the natural process of converting solar into chemical energy (i.e. photosynthesis), both capturing and reenergizing carbon dioxide. Overall, the production of renewable methane (including carbon dioxide capture) is more efficient and less material intensive than the production of biofuels derived from photosynthesis and biomass conversion.     

A new approach of sizing battery energy storage system for smoothing the power fluctuations of a PV/wind hybrid system

In this paper, a new approach for optimally sizing the storage system employing the battery banks for the suppression of the output power fluctuations generated in the hybrid photovoltaic/wind hybrid energy system. At first, a novel multiple averaging technique has been used to find the smoothing power that has to be supplied by the batteries for the different levels of smoothing of output power. Then the battery energy storage system is optimally sized using particle swarm optimization according to the level of smoothing power requirement, with the constraints of maintaining the battery state of charge and keeping the energy loss within the acceptable limits. Two different case studies have been presented for different locations and different sizes of the hybrid systems in this work. The results of the simulation studies and detailed discussions are presented at the end to portrait the effectiveness of the proposed method for sizing of the battery energy storage system. Copyright © 2016 John Wiley & Sons, Ltd.     

Sensitivity analysis for thermocline thermal storage tank design

Concentrated solar power coupled with thermal energy storage is a promising approach for providing the world with clean, renewable, sustainable and cost-competitive power on a large scale. Thermocline thermal energy storage has been proposed as an efficient and cost-competitive alternative to the traditional two-tank design. The thermocline thickness is directly linked to the efficiency of the storage tank. Sensitivity analysis is thus applied to a model of the thermocline thickness to identify the parameters that influence it the most. Results indicate that the tank height along with the thermophysical properties of the solid filler material influence the tank efficiency the most, with fluid properties and having a secondary effect.     

Integrating power systems for remote island energy supply: Lessons from Mykines,Faroe Islands

This study investigates the challenges and opportunities facing the installation of a hybrid hydrogen-renewable energy system in a remote island area disconnected from any main power grid. Islands with strong wind energy potential have the potential to become self-sufficient energy generating hubs that may even export electricity or hydrogen. This study has tested whether the combination of wind and hydrogen can replace a diesel generator on one of the Faroe Islands, Mykines. The comparison is based on an evaluation of each power system's costs, efficiency, environmental impact and suitability for the Mykines. The findings from this research can help inform those seeking to design 100% renewable energy systems for remote areas, and in particular islands. Furthermore, our comparison has value for those seeking to optimize the integration of wind turbines with hydrogen energy systems.     

A new solar based multigeneration system with hot and cold thermal storages and hydrogen production

A multigeneration system based on solar thermal energy associated with hot and cold thermal storage is designed and analyzed energetically and exergetically. The system produces electricity, a heating effect, a cooling effect, hydrogen, and dry sawdust biomass as outputs by means of organic Rankine cycles, a heat pump, two absorption chillers, an electrolyser, and a belt dryer. The intermittent behavior of the renewable energy source is addressed through the incorporation of hot and cold thermal storage systems to operate an organic Rankine cycle and provide cooling at night. The performance assessment indicates that the overall (day and night) energy and exergy efficiencies are 20.7% and 13.7%, respectively. The majority of the total exergy destruction is attributable to the sawdust belt dryer, at about 64.0%.     

Model of low spatial frequency diffractive elements recorded in photopolymers during and after recording

Photopolymer are appealing materials for diffractive elements recording. Two of their properties when they are illuminated are useful for this goal: the relief surface changes and the refractive index modifications. In this paper we use a 2-dimensional model, based on direct parameter measurements, for predicting the refractive index distributions during and after illumination. We have analyzed different recording spatial frequencies for photopolymers based on PVA/Acrylamide. This model was successfully applied to different photopolymer compositions with different values of monomer diffusion and polymerization rates.     

CMRH method as iterative solver for boundary element acoustic systems

Disceretization of boundary integral equations leads to complex and fully populated linear systems. One inherent drawback of the boundary element method (BEM) is that, the dense linear system has to be constructed and solved for each frequency. For large-scale problems, BEM can be more efficient by improving the construction and solution phases of the linear system. For these problems, the application of common direct solver is inefficient. In this paper, the corresponding linear systems are solved more efficiently than common direct solvers by using the iterative technique called CMRH (Changing Minimal Residual method based on Hessenberg process). In this method, the generation of the basis vectors of the Krylov subspace is based on the Hessenberg process instead of Arnoldi's one that the most known GMRES (Generalized Minimal RESidual) solver uses. Compared to GMRES, the storage requirements are considerably reduced in CMRH.     

The phase transformations and cycling performance of copper-tin alloy anode materials synthesized by sputtering

A sputtering technique was adopted to synthesize Sn-Cu thin film electrodes. Island Sn particles were obtained on the copper foil. Cu₆Sn₅ was spontaneously generated at the interface between Sn and Cu foil. To further improve the cycling stability, Cu source was introduced to increase the formation of Cu₆Sn₅ and to serve as a buffer during cycling. Moreover, the phase and elemental ratio of Sn and Cu varied in the synthesized electrode by alternately adjusting sputtering time for Sn and Cu. The cell synthesized by sputtering Sn for 5 min and Cu for 9 s alternately exhibited the best cycling stability. The 1st charge capacity of cell was 635 mA hg⁻¹, and the 1st efficiency was even higher than 97%. The capacity remained higher than 500 mA hg⁻¹ after 15 cycles. The phase transformation of cell was investigated through voltage profile, CV curve and in situ XRD analysis. The in situ XRD analysis confirmed that Cu₆Sn₅ could react with lithium directly without the presence of Li₂CuSn during cycling. The reaction mechanism of Cu₆Sn₅ with lithium during cycling was demonstrated to be an alloying process, and the structure of Cu₆Sn₅ was thus a low-temperature monoclinic phase.