科学家在大气中发现四种新人造气体-凯发k8官网

科学家在大气中发现四种新人造气体

文章来源：未知文章作者：enread 发布时间：2014-03-11 07:56 字体： [ ]　

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scientists at the university of east anglia have identified four new human-made gases in the atmosphere -- all of which are contributing to the destruction of the ¹ layer. new research published today in the journal nature geoscience reveals that more than 74,000 tonnes of three new chlorofluorocarbons (cfcs氟氯氟烃) and one new hydrochlorofluorocarbon (hcfc氟氯烃化合物) have been released into the atmosphere.

scientists made the discovery by comparing today's air samples with air trapped in polar firn snow -- which provides a century-old natural archive of the atmosphere. they also looked at air collected between 1978 and 2012 in unpolluted tasmania.

measurements show that all four new gases have been released into the atmosphere recently -- and that two are significantly accumulating. ² increases of this scale have not been seen for any other cfcs since controls were introduced during the 1990s. but they are nowhere near peak cfc ³ of the 1980s which reached around a million tonnes a year.

lead researcher dr johannes laube from uea's school of environmental sciences said: "our research has shown four gases that were not around in the atmosphere at all until the 1960s which suggests they are human-made."

"cfcs are the main cause of the hole in the ozone layer over antarctica. laws to reduce and phase out cfcs came into force in 1989, followed by a total ban in 2010. this has resulted in successfully reducing the production of many of these compounds on a global scale. however, legislation loopholes still allow some usage for ⁴ purposes.

"the identification of these four new gases is very worrying as they will contribute to the destruction of the ozone layer. we don't know where the new gases are being emitted from and this should be investigated. possible sources include feedstock chemicals for insecticide production and ⁵ for cleaning electronic ⁶.

"what's more, the three cfcs are being destroyed very slowly in the atmosphere -- so even if emissions were to stop immediately, they will still be around for many decades to come," he added.

this research has been funded by the natural environment research council (nerc), the national centre for ⁷ science (ncas), the european union, and the ⁸ scientific and industrial research ⁹ (csiro).

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收听单词发音

1
n.臭氧，新鲜空气
参考例句：
the ozone layer is a protective layer around the planet earth.臭氧层是地球的保护层。 the capacity of ozone can adjust according of requirement.臭氧的产量可根据需要或调节。

2
n.发出物，散发物；发出，散发
参考例句：
rigorous measures will be taken to reduce the total pollutant emission.采取严格有力措施，降低污染物排放总量。 finally,the way to effectively control particulate emission is pointed out.最后，指出有效降低颗粒排放的方向。

3
排放物( emission的名词复数 )；散发物（尤指气体）
参考例句：
most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。 dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

4
使免除[豁免]( exempt的过去式和过去分词 )
参考例句：
his bad eyesight exempted him from military service. 他因视力不好而免服兵役。 her illness exempted her from the examination. 她因病而免试。

5
溶解的，溶剂
参考例句：
it is resistant to borohydride reduction in alcoholic solvents. 在醇溶剂中，它不能被硼氢化物还原。 strains require special treatments for removal such as spotting with organic solvents. 要清除这些着色物质，需要特殊处理，例如：滴加有机溶剂。

6
（机器、设备等的）构成要素，零件，成分；成分( component的名词复数 )； [物理化学]组分； [数学]分量；（混合物的）组成部分
参考例句：
the components of a machine 机器部件 our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。

7
adj.大气的，空气的；大气层的；大气所引起的
参考例句：
sea surface temperatures and atmospheric circulation are strongly coupled.海洋表面温度与大气环流是密切相关的。 clouds return radiant energy to the surface primarily via the atmospheric window.云主要通过大气窗区向地表辐射能量。

8
n.共和国，联邦，共同体
参考例句：
he is the chairman of the commonwealth of artists.他是艺术家协会的主席。 most of the members of the commonwealth are nonwhite.英联邦的许多成员国不是白人国家。

9
n.组织，安排，团体，有机休
参考例句：
the method of his organisation work is worth commending.他的组织工作的方法值得称道。 his application for membership of the organisation was rejected.他想要加入该组织的申请遭到了拒绝。