基于优进策略的遗传算法对重油热解模型参数的估计

针对常规遗传算法全局寻优效率偏低的弱点，提出了一种优进策略，用以改进常规遗传算法。该策略将从繁衍过程中获取进化信息，自适应地改进子代分布，适时引入确定性操作，以提高全局寻优性能。提出的相关技术包括维持种群的多样性、改进交叉算子、增加Powell寻优算子等。实例测试表明这种优进策略效果良好，并已成功地应用于重油热解三集总动力学复杂数学模型的非线性参数估计。     

超薄MOF纳米片前驱体高效电催化OER反应

金属-有机骨架材料作为前驱体制备特定形貌的纳米材料用于水氧化反应(OER)，成为新的研究热点。使用溶剂热法在泡沫镍基底上合成超薄的NiCoFe-MOF纳米片，在保留其纳米片形貌的基础上原位电化学转化为金属氢（羟基）氧化物。在1 M KOH电解液中，10 mA?cm-2电流密度时的过电位仅为189 mV，Tafel斜率为35 mV/dec，且长时间电解实验表明其具有较高稳定性。原位拉曼结果表明，反应的高活性来源于反应过程中的“活性氧物种”中间体。     

CoSe2@NF双功能电催化剂用于高效碱性全解水

开发用于水分解的高效稳定、低成本非贵金属电催化剂，特别是在同一电解质中对阴极的析氢反应(HER)和阳极的析氧反应(OER)都具有高效作用的电催化剂是一项挑战。以六水合硝酸钴、尿素、氟化铵和硒粉为原料，采用水热和高温固相法在镍网上原位构筑了CoSe2@NF，采用XRD、XPS、SEM和TEM对CoSe2@NF进行物相分析和形貌表征，并在碱性电解液中对CoSe2@NF的电催化析氧和析氢性能进行了测试。结果表明，表面粗糙的串珠状纳米线结构极大地增加了CoSe2有效活性位点的数量。该催化电极在OER和HER中均表现出高而稳定的催化活性。将CoSe2@NF作为全解水槽的阴阳极，在1.6 V槽电压下即可产生10 mA/cm2的电流，并可在1.7 V的电压下稳定运行100 h。这项研究为全解水提供了一种经济有效的解决方案.     

Electrodeposition of catalytically active nickel for the oxygen evolution reaction — effects of anionic composition

Nickel electrodes were prepared by electrodeposition in electrolytes of various anionic compositions. The deposition conditions and bath types were evaluated with special emphasis on the electrocatalytic properties for the oxygen evolution reaction (OER). Electrochemical characterizations in a 5 mol/L KOH solution at 25°C showed that the electrode deposited from the chloride bath, having a low Tafel slope of 50 mV/dec and an overpotential of 396 mV at 100 mA/cm², is the most catalytically active among electrodes prepared in electrolytes of various anionic compositions. The electrode activity for the OER is related to the real surface areas, which depend on the anion compositions in the deposition bath and the deposition conditions.     

非晶态Ni—Mo合金的电沉积

从含有NiSO_4、(NH_4)_6Mo_7O_(24)、NaCl、Na_3C_6H_5O_7和NH_3·H_2O的镀液中电沉积具有金属光泽并略带银灰色的非晶态Ni-Mo合金.研究了镀液的组成、pH值及阴极电流密度等对阴极电流效率、合金组成以及合金结构的影响.合金最大钼含量为29.4at%.当镀层中钼含量大于约25at%时,为非晶态结构.此外,还研究了Ni-Mo合金的析氢催化特性.     

Kinetics of hydrogen evolution on submicron size Co, Ni, Pd and Co–Ni alloy powder electrodes by d.c. polarization and a.c. impedance studies

Submicron size Co, Ni and Co–Ni alloy powders have been synthesized by the polyol method using the corresponding metal malonates and Pd powder by reduction of PdO _x in methanol. The kinetics of the hydrogen evolution reaction (HER) in 6 M KOH electrolyte have been studied on electrodes made from the pressed powders. The d.c. polarization measurements have resulted in a value close to 120 mV decade^–1 for the Tafel slope, suggesting that the HER follows the Volmer–Heyrovsky mechanism. The values of exchange current density (i _o) are in the range 1–10 mA cm^–2 for electrodes fabricated in the study. The a.c. impedance spectra measured at several potentials in the HER region showed a single semicircle in the Nyquist plots. Exchange current density (i _o) and energy transfer coefficient () have been calculated by employing a nonlinear least square-fitting program.     

The effect of reaction conditions on montmorillonite-catalysed peptide formation

Oligomerization of glycine (gly) and diglycine (gly₂) on montmorillonite was performed as cyclic, drying-wetting process at temperatures below 100°C, under varying reaction conditions. The influence of substrate/clay ratio, temperature and pH was found to be different for amino acid (AA) dimerization, cyclic anhydride (CA) formation and peptide chain elongation. High temperatures and neutral pH favour CA formation over diglycine production. An AA/catalyst ratio of 0.2 mmol/g leads to optimal yields. This supports the assumption that amino acid dimerization and CA formation take place at the edges of clay particles. Peptide chain elongation, starting from gly₂, produces higher yields at higher temperatures and neutral pH.     

粗四氯化钛除钒工艺现状及进展

论述了海绵钛和钛白生产中四氯化钛精制除钒工艺生产现状和研究进展,从技术、经济和环保角度对几种主要的除钒方法进行了综合性的评价和探讨。