Studies on electrocatalytic performance of titanium oxide electrode modified with Pt toward the oxidation of methanol

Electrocatalytic performance of the Pr-TiOx/Ti electrode prepared with electrochemical reduction-oxidation method toward the oxidation of methanol has been studied, The experimental results showed that the Pt-TiOx/Ti electrode has a high electrocatalytic activity and good stability for the electrocatalytic oxidation of methanol, By means of electrochemical, XPS, STM and in-situ FTIR techniques, it was found that one reason for the electrode to exhibit an excellent performance is attributed to the high dispersion between nanosized Pt and TiOx particles, The low adsorption ability of the intermediate derived from methanol, such as linearly adsorbed CO species on the electrode surface due to the interaction between Pt and TiOx, also results in the excellent performance.

甲醇在铂修饰的氧化钛电极上电催化氧化行为的研究

运用电化学方法评价了电化学阴极还原 -阳极氧化两步法制得的以钛为基体的铂修饰的钛氧化物 ( Pt-Ti Ox/Ti)电极对甲醇电催化氧化的性能 ,结果表明 ,制得的修饰电极对甲醇氧化呈现了很高的电催化活性和好的稳定性 .通过 X光电子能谱 ( XPS)、扫描隧道显微镜 ( STM)和现场傅立叶变换红外 ( FTIR)反射光谱等技术 ,发现修饰电极对甲醇氧化具有高的电催化性能 ,可归属于纳米级 Pt粒子在 Ti Ox中的高度分散及由于 Pt和 Ti Ox的相互作用 ,使电极表面对甲醇氧化中间产物 CO的吸附量大大降低

Experimental warming, not grazing, decreases rangeland quality on the Tibetan Plateau

We investigated experimental warming and simulated grazing ( clipping) effects on rangeland quality, as indicated by vegetation production and nutritive quality, in winter-grazed meadows and summer- grazed shrublands on the Tibetan Plateau, a rangeland system experiencing climatic and pastoral land use changes. Warming decreased total aboveground net primary productivity ( ANPP) by 40 g . m(-2) . yr(-1) at the meadow habitats and decreased palatable ANPP ( total ANPP minus non- palatable forb ANPP) by 10 g . m(-2) . yr(-1) at both habitats. The decreased production of the medicinal forb Gentiana straminea and the increased production of the non- palatable forb Stellera chamaejasme with warming also reduced rangeland quality. At the shrubland habitats, warming resulted in less digestible shrubs, whose foliage contains 25% digestible dry matter ( DDM), replacing more digestible graminoids, whose foliage contains 60% DDM. This shift from graminoids to shrubs not only results in lower- quality forage, but could also have important consequences for future domestic herd composition. Although warming extended the growing season in non- clipped plots, the reduced rangeland quality due to decreased vegetative production and nutritive quality will likely overwhelm the improved rangeland quality associated with an extended growing season.Grazing maintained or improved rangeland quality by increasing total ANPP by 20 - 40 g . m(-2) . yr(-1) with no effect on palatable ANPP. Grazing effects on forage nutritive quality, as measured by foliar nitrogen and carbon content and by shifts in plant group ANPP, resulted in improved forage quality. Grazing extended the growing season at both habitats, and it advanced the growing season at the meadows. Synergistic interactions between warming and grazing were present, such that grazing mediated the warming- induced declines in vegetation production and nutritive quality. Moreover, combined treatment effects were nonadditive, suggesting that we cannot predict the combined effect of global changes and human activities from single- factor studies.Our findings suggest that the rangelands on the Tibetan Plateau, and the pastoralists who depend on them, may be vulnerable to future climate changes. Grazing can mitigate the negative warming effects on rangeland quality. For example, grazing management may be an important tool to keep warming- induced shrub expansion in check. Moreover, flexible and opportunistic grazing management will be required in a warmer future.

一个多智能体机器人协作装配系统

介绍了一个基于多智能体概念实现的多机器人协作装配系统——ＭＲＣＡＳ（Ｍｕｌｔｉ－ＲｏｂｏｔＣｏｏｐｅｒａｔｉｖｅＡｓｓｍｂｌｙＳｙｓｔｅｍ）。该系统由组织级计算机、三台工业机器人和一台全方位移动小车（ＯＤＶ）组成，采用分层递阶体系结构。利用ＭＲＣＡＳ系统进行了多机器人协作装配的实验：在ＯＤＶ装配平台上，四台机器人合作装配一个大型桁架式工件。该工件具有多种装配构型，但任何一台机器人不能独立完成装配。