科学家发现机场液体快速检测方法-凯发k8官网

科学家发现机场液体快速检测方法
文章来源:未知 文章作者:meng 发布时间:2009-10-20 02:48 字体: [ ] 
(单词翻译:双击或拖选)

scientists say they have developed a quick technique for detecting liquids that could be used as explosives.

科学家称,他们已经发现一种探测可爆炸液体的快速方法。

the prototype scanner is compact and made of comparatively cheap parts
the prototype scanner is compact and made of comparatively cheap parts

if commercialised, the new method could potentially end 1 on liquids carried onto commercial airlines.

the light-based approach uses cheap 2 and can reliably identify a range of liquids in just one-fifth of a second, the german scientists say.

the work, published in the journal superconductor science and technology, could have additional applications.

a number of research efforts are under way to solve the liquids problem for airline passengers.

there are, in fact, several techniques which could be employed. these include nuclear magnetic spectroscopy(光谱学), which uses the magnetic properties of chemical 3(细胞,核) to obtain information about a sample.

however, all of the available options are either too expensive or require too much time for the practical screening of thousands of pieces of luggage.

chemical '4'

now, a group at the research centre juelich in germany has proposed a technique they call hilbert spectroscopy.

their idea is to use a very wide 5 of light to identify either liquids that could be mixed to form an explosive, or that are already mixed.

all materials reflect light in a way that is particular to their identity, and many techniques used in both security and scientific research rely on measuring the reflection or absorption(吸收) of light to identify materials.

however, in practice, measurements on baggage are confused by the packaging and items inside.

researchers behind the new technique say they have managed to get around this problem by using a wide range of frequencies between a few gigahertz(千兆赫) and a few terahertz(太赫兹波) -which is between 100 and 10,000 times lower in frequency than the visible light that passes easily through labels and packaging.

the trick, they say, is to use a "nano-electronic" device known as a josephson 6. this allows the frequencies of light reflected from a sample to be quickly added up. this in turn provides a chemical "fingerprint" of the item being analysed.

the principal advantage of using the josephson junction is that it can span the low and high frequency ranges covered by other, significantly more expensive devices, said yuri divin, of the research centre juelich.

"no one type of spectroscopy can operate from a few gigahertz to a few terahertz [in the way] hilbert spectroscopy [can]," he told bbc news.

"[in] applications where you need high-speed operation - such as security screening - it should happen fast and in a "broadband" [way] to make it reliable with a low number of false alarms. hilbert spectroscopy does that," he added.

dr divin conceded that further developments are necessary to refine the approach. but the researchers are confident the technique can be 7 to security screening.

"we've shown that it works, and it works well. but this is only the scientific part we have published," dr divin said.

"we have to integrate(整合) this into a 2-d scanner... for a commercial device."



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1 81e12dac658cfd4c590486dd6f7523cf     
约束( restriction的名词复数 ); 管制; 制约因素; 带限制性的条件(或规则)
参考例句:
  • i found the restrictions irksome. 我对那些限制感到很烦。
  • a snaggle of restrictions 杂乱无章的种种限制
2 4725dcf446a342f1473a8228e42dfa48     
(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。
3 thcxf     
n.核
参考例句:
  • to free electrons, something has to make them whirl fast enough to break away from their nuclei. 为了释放电子,必须使电子高速旋转而足以摆脱原子核的束缚。
  • energy is released by the fission of atomic nuclei. 能量是由原子核分裂释放出来的。
4 4kxxx     
n.指纹;vt.取...的指纹
参考例句:
  • the fingerprint expert was asked to testify at the trial.指纹专家应邀出庭作证。
  • the court heard evidence from a fingerprint expert.法院听取了指纹专家的证词。
5 trhy6     
n.谱,光谱,频谱;范围,幅度,系列
参考例句:
  • this is a kind of atomic spectrum.这是一种原子光谱。
  • we have known much of the constitution of the solar spectrum.关于太阳光谱的构成,我们已了解不少。
6 n34xh     
n.连接,接合;交叉点,接合处,枢纽站
参考例句:
  • there's a bridge at the junction of the two rivers.两河的汇合处有座桥。
  • you must give way when you come to this junction.你到了这个路口必须让路。
7 tz2zxa     
adj.应用的;v.应用,适用
参考例句:
  • she plans to take a course in applied linguistics.她打算学习应用语言学课程。
  • this cream is best applied to the face at night.这种乳霜最好晚上擦脸用。
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