首片实用型人造树叶的奥秘-凯发k8官网

首片实用型人造树叶的奥秘

文章来源：未知文章作者：enread 发布时间：2012-05-11 05:52 字体： [ ]　

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a ¹ description of development of the first practical artificial leaf -- a ² in the drive for sustainable energy that ³ the process, ⁴（光合作用） , that green plants use to convert water and sunlight into energy -- appears in the acs journal accounts of chemical research. the article notes that unlike earlier devices, which used ⁵ ingredients, the new device is made from inexpensive materials and employs low-cost engineering and manufacturing processes. daniel g. nocera points out that the artificial leaf responds to the vision of a famous italian chemist who, in 1912, predicted that scientists one day would uncover the "guarded secret of plants." the most important of those, nocera says, is the process that splits water into hydrogen and oxygen. the artificial leaf has a sunlight collector sandwiched between two films that generate oxygen and hydrogen gas. when dropped into a jar of water in the sunlight, it bubbles away, releasing hydrogen that can be used in fuel cells to make electricity. these self-contained units are attractive for making fuel for electricity in remote places and the developing world, but designs demonstrated thus far rely on metals like ⁶ and manufacturing processes that make them cost-prohibitive.

to make these devices more widely available, nocera replaced the platinum ⁷ that produces hydrogen gas with a less-expensive nickel-molybdenum-zinc compound. on the other side of the leaf, a cobalt（钴） film generates oxygen gas. nocera notes that all of these materials are abundant on earth, unlike the rare and expensive platinum, noble metal oxides and semiconducting materials others have used. "considering that it is the 6 billion nonlegacy users that are driving the enormous increase in energy demand by midcentury, a research target of delivering solar energy to the poor with discoveries such as the artificial leaf provides global society its most direct path to a sustainable energy future," he says.

the author acknowledges support from the national science foundation and the chesonis family foundation.

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收听单词发音

1
adj.详细的，详尽的，极注意细节的，完全的
参考例句：
he had made a detailed study of the terrain.他对地形作了缜密的研究。 a detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

2
n.里程碑；划时代的事件
参考例句：
the film proved to be a milestone in the history of cinema.事实证明这部影片是电影史上的一个里程碑。 i think this is a very important milestone in the relations between our two countries.我认为这是我们两国关系中一个十分重要的里程碑。

3
n.模仿名人言行的娱乐演员，滑稽剧演员( mimic的名词复数 )；善于模仿的人或物v.（尤指为了逗乐而）模仿( mimic的第三人称单数 )；酷似
参考例句：
methods:models were generate by ct scan,mimics software and abaqus software. 方法：采用ct扫描，mimics软件和abaqus软件的cad进行三维有限元模型的创建。来自互联网 relaxing the mind and body mimics the effect that some blood-pressure pills would have. 放松身心会产生某些降压药才能产生的效果。来自辞典例句

4
n.光合作用
参考例句：
in apple trees photosynthesis occurs almost exclusively in the leaves.苹果树的光合作用几乎只发生在叶内。 chloroplasts are the structures in which photosynthesis happens.叶绿体就是光合作用发生的地方。

5
adj.昂贵的，价值高的，豪华的
参考例句：
it must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。 this dictionary is very useful,only it is a bit costly.这本词典很有用，左不过贵了些。

6
n.白金
参考例句：
i'll give her a platinum ring.我打算送给她一枚白金戒指。 platinum exceeds gold in value.白金的价值高于黄金。

7
n.催化剂，造成变化的人或事
参考例句：
a catalyst is a substance which speeds up a chemical reaction.催化剂是一种能加速化学反应的物质。 the workers'demand for better conditions was a catalyst for social change.工人们要求改善工作条件促进了社会变革。