含多电解槽的新能源制氢能量管理优化

新能源制氢系统是提升风能、太阳能等新能源发电消纳的有效途径。目前国内外关于电解槽能量管理的相关研究以单电解槽为主。单电解槽能量管理未考虑电解槽非线性的工作特性,难以兼顾多个电解槽制氢效率,影响系统经济性。论文针对含有多电解槽新能源制氢系统的能量管理问题进行了研究。以新能源消纳率、经济收益、制氢率为目标,考虑单个电解槽运行特性及生产约束等条件,建立包含风电、光伏、蓄电池、电解槽多个模块的能量管理优化模型,并采用SPEA2算法求解多目标优化问题。仿真研究表明,所提能量管理策略能够实现新能源发电的100%消纳,单位制氢效益可提升5.15%。因此,多电解槽制氢系统进行有效的能量管理有助于提高制氢效率,有效克服单电解槽运行及能量管理的不足。     

Amine Coordinated Electron-Rich Palladium Nanoparticles for Electrochemical Hydrogenation of Benzaldehyde

Electrocatalytic hydrogenation (ECH) is a burgeoning strategy for the sustainable utilization of hydrogen. However, how to effectively suppress the competitive hydrogen evolution reaction (HER) is a big challenge to ECH catalysis. In this study, amine (NH₂ R)-coordinated Pd nanoparticles loaded on carbon felt (Pd@CF) as a catalyst is successfully synthesized by a one-step solvothermal reduction method using oleylamine as the reducing agent. An exceptional ECH reactivity on benzaldehyde is achieved on the optimal Pd@CF catalyst in terms of a high conversion (89.7%) and selectivity toward benzyl alcohol (89.8%) at −0.4 V in 60 min. Notably, the Faradaic efficiency for producing benzyl alcohol is up to 90.2%, much higher than that catalyzed by Pd@CF-without N-group (41.1%) and thecommercial Pd/C (20.9%). The excellent ECH performance of Pd@CF can be attributed to the enriched electrons on Pd surface resulted from the introduction of NH₂ R groups, which strengthens both the adsorption of benzaldehyde and the adsorbed hydrogen (H_ads) on Pd, preventing the combination of H_ads to form H₂, that is, inhibiting the HER. This study gives a new insight into design principles of highly efficient electrocatalysts for the hydrogenation of unsaturated aldehydes molecules.     

我国青年现阶段价值观演变状况与导向

在市场经济的冲击下,我国青年现阶段的价值观发生了很大的变化,主要表现为:一元化价值观向多元化价值观演变;理想主义价值取向转为务实求实的价值取向;群体本位向个体本位取向偏移。在这个价值观转变当中,往往出现一些畸形的价值取向,所以应坚持正确的导向,强化新的价值观。     

中国传统符号的演变——门

人类学会构筑房屋并为自己的进出留下一个进出方便的口,门就产生了。门是一个极为抽象的形态,一个变化万千的符号,这个古老的符号——门的形态变化一直在随着科技的发展而演变,无论是古人还是后人都在其中精心地演绎着中国的传统民族文化。     

基于LDA模型的新闻话题的演化

新闻话题及演化的研究可以帮助人们快速了解和获取新闻内容。提出了一种挖掘新闻话题随时间变化的方法,通过话题抽取和话题关联实现话题的演化。首先应用LDA(Latent Dirichlet Allocation Model)对不同时间段的文集进行话题的自动抽取,话题数目在不同时间段是可变的;计算相邻时间段中任意两个话题的分布距离实现话题的关联。实验结果证明该方法不但可以描述同一个话题随时间的演化过程,还可以描述话题内容随时间的变化,反映了话题(或子话题)之间多对多的演化关系。     

Thermodynamic studies on the complete phase diagram of aqueous two phase system containing polyethylene glycol dimethyl ether 2000 and di-potassium hydrogen phosphate at different temperatures

The liquid-liquid equilibrium of polyethylene glycol dimethyl ether 2000 (PEGDME₂₀₀₀)+K₂HPO₄+H₂O system has been determined experimentally at T=(298.15,303.15,308.15 and 318.15) K. The liquid-solid and complete phase diagram of this system was also obtained at T=(298.15 and 308.15) K. A nonlinear temperature dependent equation was successfully used for the correlation of the experimental binodal data. Furthermore, a temperature dependent Setschenow-type equation was successfully used for the correlation of the tie-lines of the studied system. Moreover, the effect of temperature on the binodal curves and the tie-lines for the investigated aqueous two-phase system have been studied. Also, the free energies of cloud points for this system and some previously studied systems containing PEGDME₂₀₀₀ were calculated from which it was concluded that the increase of the entropy is the driving force for formation of aqueous two-phase systems. Additionally, the calculated free energies for phase separation of the studied systems were used to investigate the salting-out ability of the salts having different anions. Furthermore, the complete phase diagram of the investigated system was compared with the corresponding phase diagrams of previously studied systems, in which the PEGDME₂₀₀₀ has been used, in order to obtain some information regarding the phase behavior of these PEGDME₂₀₀₀+salt+water systems.     

面向本体的服务组合差分进化策略

针对目前Web服务描述服务功能的语义不够深入而使服务识别组合能力欠佳的问题,提出一种面向本体的语义服务功能描述方法,建立本体间的映射关系模型和服务质量关系模型,通过改进差分进化算法求解,得到一种较好的服务组合识别方法。在九寨沟旅游管理信息系统中的应用表明,该方法比传统的方法优越。     

基于差分蜂群算法的电力系统经济负荷分配

针对电力系统经济负荷分配问题,提出一种有效的差分蜂群算法．受差分进化算法的启发,该算法基于差分进化操作改进了雇佣蜂的搜索方式,提高了探索能力和收敛速度．此外,提出一种有效的修复机制以保证新个体的可行性．该算法在带有阀点效应和多燃料特征的典型电力系统经济负荷分配问题上进行了测试．仿真结果验证了所提算法的有效性．     

Evolving Teams of Predictors with Linear Genetic Programming

This paper applies the evolution of GP teams to different classification and regression problems and compares different methods for combining the outputs of the team programs. These include hybrid approaches where (1) a neural network is used to optimize the weights of programs in a team for a common decision and (2) a realnumbered vector (the representation of evolution strategies) of weights is evolved with each term in parallel. The cooperative team approach results in an improved training and generalization performance compared to the standard GP method. The higher computational overhead of team evolution is counteracted by using a fast variant of linear GP.     

A new dynamic hydrogen reference electrode for applications in thin-film sensor systems

The realization and applicability of a new dynamic hydrogen reference electrode (DHRE) within an electrochemical microcell for sensor applications is reported. The electrodes are fabricated in thin-film technology and fixed within a flow-through device. An experimental setup for accurate electrochemical potential measurements is described. Smooth platinum, platinized platinum and pHEMA coated electrodes are investigated with regard to their initialization behavior, stability, reproducibility and interference with electrolytes. It is found that platinized platinum DHREs show excellent stability and reproducibility. For uncoated electrodes, the electrochemical potential is established within seconds. The potential is independent of the pH value within the range of pH 4–10. Interference with sulfate and phosphate is observed. Thus, the platinized platinum DHRE is well suited for bioanalytical sensor applications, where the pH value is buffered and the concentrations of the disturbing anions are constant or very low.