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清镇市人民医院体检中心电话Science and Technolgy.科技。Modern alchemy.现代炼金术。Turning a line.进入新的一行。The race to extend the periodic table continues.扩展元素周期表的比赛仍在继续。ONE of the first inklings that chemistry has an underlying pattern was the discovery, early in the 19th century, of lithium, sodium and potassium-known collectively as the alkali metals. Though different from each other they have strangely similar properties. This was one of the observations that led a German chemist called Johann Debereiner to wonder if all chemical elements came in families.早在19世纪,人们对化学潜在规律已有模糊认知之时,锂、钠、钾被发现,它们同被称为碱金属。虽然并不相同,它们却有着不可思议的相似性质。正是这项发现,使德国化学家Johann Debereiner产生怀疑,是否所有的化学元素都是成族出现的。It took decades to tease out the truth of Debereiners conjecture, and thus to construct the periodic table-in which the alkali metals form the first column. And it took decades more to explain why the table works (it is to do with the way electrons organise themselves in orbit around atomic nuclei). But it is a fitting tribute to Debereiners insight that, if all goes well, some time in the next few months will bring the creation of a new alkali metal, element number 119, by his countryman Christoph Dullmann of the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt. With that addition the table will do something which has never happened before. It will grow a new row.科学家们实Debereiner猜想的正确性用了数十年的时间,也因此建立了元素周期表——碱金属组成了第一族。其后又花费了数十年的时间来解释为何周期表是起作用的(与电子绕原子核外轨道运动的方式有关)。在即将到来的几个月里,如果一切顺利,德国达姆施塔特市GSI亥姆霍兹重离子研究中心的Christoph Dullmann将合成一个新的碱金属,即元素周期表中第119号元素。这也恰恰彰显了其同胞Debereiner的深刻洞察力。有了这个元素,周期表会发生前所未有的变化——延伸出新的一行。Come in number 119.119号元素即将出现。An elements atomic number is the number of protons in its nucleus. These, despite being mutually repulsive because they are positively charged, are held together by a phenomenon called the strong nuclear force. Some of this force is also supplied by neutrons, which outnumber protons in most nuclei and have no electric charge. If, however, there are too many or too few neutrons in a nucleus, that nucleus becomes unstable-in other words, it is radioactive. And the vagaries of quantum physics mean that ;too many; and ;too few; sometimes overlap, and there is thus no stable isotope (or variant, with fewer or more neutrons) of a particular element.一种元素的原子序数是其原子核中的质子数。虽然质子之间因带正电荷而相互排斥,但被强核力聚集在一起。强核力的一部分也由中子提供,在大多数原子核内,中子比质子数量多,并且不带电荷。然而,如果核内中子过多或过少,原子核将变得不稳定——即具有放射性。难以捉摸的量子力学表明,中子;太多;和;太少;有时会重叠出现,因而一些特定的元素没有稳定的同位素(或称变体,核内中子数不同)。This happens at two places-islands of instability, if you like-in the middle of the table. As a result technetium, element number 43, and promethium, 61, are always radioactive (and are not found naturally in detectable quantities). Further down the table, where nuclei get heavier and elements less familiar, instability happens more and more often. No element heavier than lead (number 82) has a stable isotope, and above number 92 (uranium) lifetimes are so short that these substances are almost non-existent in nature. Such ;transuranic; elements can, however, be made artificially by the fusion of lighter ones. And that is precisely what Dr Dullmann intends to do in the case of element 119, by firing titanium atoms (number 22) at those of berkelium (97) and hoping some of them merge.这样的不稳定元素岛在周期表中部的两处出现。锝(43号元素)和钷(61号元素)都是放射性的,并且在自然中的存在数量无法侦测。周期表中继续向下看,元素的原子核都变得越来越重,元素也越来越不为人所熟悉,不稳定性更是频繁出现。比铅(82号)更重的元素都没有稳定的同位素,在铀(92号)之后的元素寿命太短,以致于在自然界中几乎不存在。这些;超铀;元素可以通过更轻元素的熔合来人工合成,这也是Dullmann士想对119号元素应用的,将钛(22号)原子与锫(97号)原子大量熔合,希望其中一些可以合并产生新元素。Making a new element is tricky. The titanium atoms must be travelling fast enough in GSIs particle accelerator to overcome the repulsion between their protons and those of the berkelium, yet slowly enough to avoid ripping the newly formed atom of element 119 apart before it has had time to settle down. With the right mix, though, Dr Dullmann is confident that one or two atoms of 119 will be created over the course of the next few months, and will hang around long enough to be detected.合成一种新元素非常复杂。GSI的粒子加速器中的钛原子必须有足够快的移动速度来克自身质子间的斥力与锫质子间的斥力,却又必须足够慢,以防将还没时间稳定下来的新合成元素119号撞裂。尽管需要良好的混合,Dullmann士相信,在接下来的几个月中,会合成一两个119号元素的原子,并能稳定足够长的时间以被检测到。That will be a feather in GSIs cap in its friendly competition with the Lawrence Berkeley National Laboratory, in California (after which berkelium is named) and the Joint Institute for Nuclear Research in Dubna, Russia (after which dubnium, number 105, is named). Number 110 is named darmstadtium, and these three laboratories are, between them, responsible for the creation of all the transuranics found so far-most notably plutonium, which was used to blow up Nagasaki in 1945 and thus end the second world war.在与加利福尼亚州的劳伦斯伯克利国家实验室(锫命名的由来之处)和俄罗斯杜布纳的联合核研究所(105号元素钍命名的由来之处)竞争的过程中,合成119号元素将会是GSI值得自豪的卓越成就。GSI实验室合成了110号元素,它也因此被命名为鐽;不止如此,这三所实验室合成了迄今为止所有的超铀元素。尤其引人注目的是钚,正是1945年在长崎爆炸的原子弹所使用的元素,也因此结束了第二次世界大战。The islands of the blessed.有福之岛。Modern transuranic research is more peaceful than it was in the 1940s. Indeed, sceptics might wonder at the value of creating new elements a mere atom or two at a time for little reason other than to show that it can be done. There is, however, method in the madness. Just as technetium and promethium are islands of instability in parts of the periodic table which are not normally radioactive, so many physicists believe that in the unstable part at the bottom there lies an island of stability. Their prediction is that nuclei containing 184 neutrons (which would have atomic numbers in the 120s) will hang around for sensible amounts of time-possibly as long as several million years. That would at least give them a chance to be useful.现代超铀元素的研究比上世纪40年代和平了许多。的确,怀疑论者会质疑,创造一个新的元素一次仅一、两个原子,只为展示它可以被合成,这样做究竟意义何在。然而,这样的举动虽看起来怪异,实际上却也合乎情理。正如周期表中的锝、钷是在通常没有放射性的地方出现的不稳定岛,所以许多物理学家认为,在不稳定部分中实际潜藏着稳定元素岛。他们预测,有184个中子的原子核(原子序数应在120-130之间)会稳定出现足够长的时间——也许是几百万年。这起码使它们可以被利用变为可能。Dr Dullmanns version of element 119 will not quite be there. It will have only 177 neutrons. But if it can be made, it will be a stepping stone towards the fabled island of stability, which is generally agreed to be a worthwhile destination. That it will be one in the eye for the Americans and the Russians as well is purely coincidental.Dullmann士所述的119号元素也并不能达到稳定岛,它只有177个中子。但如果119号元素可以合成,将会是走向传说中的稳定岛的一个台阶,而稳定元素岛是公认的有价值的目的地。这也将会同时给美国人和俄罗斯人带来打击。 /201209/197633 遵义医学院附属医院电话预约挂号云岩区妇幼保健院孕前检查多少钱

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