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托福TPO-08 Lecture 4

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Pro:So, are there any questions?

教授:那么,有什么问题吗?
Stu:Yes, um, Professor Harrison, you were saying that the periodic table is predictive.
学生:Harrison教授,你说元素周期表是可预测的,
What exactly does that mean?
究竟是什么意思呢?
I mean I understand how it organize the elements but where's the prediction?
我明白它如何组织这些元素,但如何预测呢?
Pro:Ok, let's look at our periodic table again.
教授:好的,让我们再看一下周期表。
Ok, it is a group of elements in the categories that share certain properties, right?
它把元素按其共有的特质分类对吗?
Stu:Um-huh.
学生:是的。
Pro:And it is ranged according to increasing atomic number, which is…
教授:它按原子数递增排序,这个原子数就是…
Stu:The number of protons in each atom of an element.
学生:是元素原子中的质子数。
Pro:Right, well, early versions of the periodic table had gaps, missing elements.
教授:对,早期的周期表有空缺,丢失的元素。
Every time you had one more proton, you had another element.
每多一个质子,就有了另一种元素。
And then, oops, there have been atomic number, for which there's no known element.
但是有相应的原子数,却不知道相应的元素是什么。
And the prediction was that the element, with that atomic number existed someway, but it just haven't been found yet.
而预测正是指那个原子数确定但还仍未被发现的元素。
And its location in the table would tell you what properties that you should have.
它在表中的位置可以告诉我们它的特性。
It was really pretty exciting for scientists at that time to find these missing elements and confirm their predictive properties.
对那个时候的科学家来说找到这些缺失的元素并确认它们的预定特质是件很令人激动的事。
Um, actually, that reminds other, other very good example of all these, element 43.
事实上,这让我想起来另一个非常好的例子,就是第43号元素。
See on the table, the symbol for element 42 and 44.
看表格中42号及44号元素的符号。
In early versions of the table, there was no symbol for element 43 protons because no element with 43 protons had been discovered yet.
在早期的周期表中,43号元素没有符号因为那是有43个质子数的元素尚未被发现。
So the periodic table had gap between elements 42 and 44.
所以周期表上在42和44号元素中间有空缺。
And then in 1925, a team of chemists led by scientist named Ida Tack's claimed they had found element 43.
而后在1925年,由一位名叫Ida Tack的科学家带领的化学家团队声称他们找到了43号元素。
They had been using a relatively new technology called X-ray spectroscopy, and they were using this to examine an ore sample.
他们正在使用一项相对较新的技术X射线光谱学检查一种矿石样本。
And they claimed that they'd found an element with 43 protons.
他们称找到了有43个质子的元素,
And they named it Masuria.
他们将其命名为Masuria。
Stu:Um, Professor Harrison, then, how come in my periodic table, here, element 43 is Tc, that's Technetium, right?
学生:Harrison教授,那为什么我们元素周期表中43号元素是Tc,那是锝对吗?
Pro:Ok, let me add that.
教授:好吧,我补充一下,
Actually, um, that's the point I'm coming to.
实际上,我马上就要讲到这点。
Hardly anyone believed that Tack's discovered the new element.
当时几乎没有人相信Tack发现了新元素。
X-ray spectroscopy was a new method at that time.
因为那时的X射线光谱学是新方法,
And they were never able to isolate enough Masurium to have available sample to convince everyone the discovery.
他们无法分离出足够多的Masurium作为使人信服的样本。
So they were discredited.
所以他们没有被人们相信。
But then, 12 years later in 1937, a different team became the first to synthesize the element using a cyclotron. And that element had…
但是后来,12年后的1937年,另一支队伍首次使用回旋加速器合成了一种元素。而这种元素有…
Stu:43 protons?
学生:43个质子?
Pro:That's right, but they named it Technetium to emphasize that it was artificially created with technology.
教授:对,但是他们将它命名为Technetium以强调它是由技术人工合成的。
And people thought that synthesizing these elements, it artificially was the only way to get it.
而且人们认为人工合成这一元素是唯一得到它的方法。
We still haven't found it currently in nature.
我们至今无法在自然界中找到它。
Now element 43 would be called Masurium or Technetium is radioactive.
43号元素,无论是Masurium还是Technetium,都是具有放射性的。
Why is that matter?
这有什么关系呢?
What is true of radioactive element?
放射性元素有何特征?
Stu:It decays it turns into other elements.
学生:放射性元素会衰变,转变成其他元素。
Oh, so does that explain why was missing in periodic table?
哦,这是不是解释了为什么它在元素周期表中曾一度缺失?
Pro:Exactly, because of radioactive decay, element 43 doesn't last very long.
教授:正是。由于放射性的衰变,43号元素不能长久存在。
And therefore, if that ever had been present on earth, it would decay ages ago.
因此如果它曾经在地球上存在过,也早就衰变了。
So the Masurium people were obviously wrong, and the Technetium people were right. Right?
所以那时发现Masurium的人显然错了,而发现Technetium的人是对的。是吧?
Well, that was then, now we know that element 43 does occur naturally.
不过那是以前,现在我们知道43号元素在自然中确实存在。
It can be naturally generated from Uranium atom that has spontaneous split.
它可以从铀原子自发的裂变中自然产生。
And guess what, the ore sample that the Masurium group was working with had plenty of Uranium enough to split into measurable amount of Masurium.
猜猜看发生了什么,发现Masurium的小组研究的矿石样品中含有足够的铀,分裂成一定量的Masurium。
So Tack's team might very well have found small amounts of Musurium in the ore sample just that once was generated from split Uranium decayed very quickly.
所以Tack的团队可能真的在矿石样品中发现了小量Masurium,只是它一从铀裂变中产生后就迅速衰变了。
And you know here's an incredible irony,
而且很讽刺的是,
Ida Tack, led the chemist of that Musurium team, and were she the first to suggest that Uranium could break up into small pieces but she didn't know that that was the defense of her own discovery of element 43.
发现Masurium的化学家Ida Tack,她是第一个提出铀可以分解成小片,但她不知道这成了她发现43号元素的证据。
Stu:So is my version of periodic table wrong? Should element 43 really be called Musurium?
学生:所以是我们这版的周期表错了?43号元素应该称为Masurium?
Pro:Maybe, but it's hard to tell for sure after all this time, if Ida Tack's group did discover element 43.
教授:也许,但是你们知道已经过去那么久,很难说 Ida Tack 的队伍是否发现了 43 号元素。
They didn't, um, publish enough details on their method or instruments for us to know for sure.
他们没有发布关于他们使用的方法或是仪器的足够多的细节信息使我们确认。
But I'd like to think element 43 was discovered twice.
但是我愿意相信 43 号元素被两次发现。
As Musurium, it was first element to discover that occurs in nature only from spontaneous vision,
作为 Masurium,它是首次从自然裂变中发生的自然元素,
and as Technetium, it was the first element discovered in the laboratory.
作为Technetium,它首次在实验室发现。
And of course, it was an element the periodic table let us to expect existed before anyone had found it or made it.
当然,它是一种在被任何人发现或是制造之前,周期表让我们相信它存在的元素。

重点单词   查看全部解释    
element ['elimənt]

想一想再看

n. 元素,成分,组成部分,(复数)恶劣天气

 
certain ['sə:tn]

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adj. 确定的,必然的,特定的
pron.

 
understand [.ʌndə'stænd]

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vt. 理解,懂,听说,获悉,将 ... 理解为,认为<

 
defense [di'fens]

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n. 防卫,防卫物,辩护
vt. 防守

 
symbol ['simbəl]

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n. 符号,标志,象征

联想记忆
available [ə'veiləbl]

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adj. 可用的,可得到的,有用的,有效的

联想记忆
split [split]

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n. 劈开,裂片,裂口
adj. 分散的

 
spontaneous [spɔn'teiniəs]

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adj. 自发的,自然产生的

联想记忆
isolate ['aisəleit]

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vt. 隔离,使孤立
adj. 孤立的,单独的

联想记忆
organize ['ɔ:gənaiz]

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v. 组织

 

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