镨

Lanthanides belong to the sixth cycle of the periodic table Ⅲ B family, are all solid metal, they are La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, holmium, erbium, thulium, ytterbium, and lutetium were 15 kinds of metals and their periphery are two layers of electronic 5d16s2, while the peripheral third layer f orbital but never zero to 14, so the external electronic structure of 4f0-145d16s2, and therefore these elements in oxidation number are to 3, very close chemical properties, extraction, when it is difficult to separate them they are mostly multi-element mineral mix, more difficult to increase refining, and their atomic number of 57-71, one by one to increase the number of protons the nucleus, and thus extranuclear electron of gravity is also growing, so that atomic radius decreases with increasing atomic number Z, which makes lanthanides contraction, ionic radius is also reduced, which also makes Zr, Hf, Nb and Ta, Mo and W, the atom and ionic radius very close to each other they also determine a similar nature, resulting in difficult separation, also the tribe Ⅷ of the fifth cycle, ruthenium, rhodium, palladium, and the sixth cycle, osmium, iridium, platinum is very similar in nature, thus The six elements, said platinum group elements.

镧系元素属于周期表第六周期中ⅢB族，全部是固体金属，它们是镧、铈、镨、钕、钷、钐、铕、钆、铽、镝、钬、铒、铥、镱和镥共十五种金属元素，它们的外围两层的电子均是5d16s2，而外围第三层的f轨道电子却从零增加到14个，所以外围电子结构为4f0－145d16s2，而使这些元素氧化数均为＋3，化学性质极为接近，提炼时很难分开，它们的矿石又大多是多种元素混在一起的，更增加提纯难度，它们的原子序数为57－71，核内质子数逐个增加，因而对核外电子引力也不断增强，使原子半径随原子序数Z增加而减小，这就使镧系元素收缩、离子半径也缩小，这也使得Zr和Hf，Nb和Ta、Mo和W等原子和离子半径都很接近、也决定了它们彼此性质类似，以致难以分离、也使第Ⅷ族中第五周期的钌、铑、钯和第六周期的锇、铱、铂在性质上极为相似，因而称这六个元素为铂系元素。

Methods Effects of yttrium chloride and praseodymium chloride on human lymphocytes cultured in vitro were studied by micronucleus test.

用微核试验法研究了氯化钇和氯化镨对体外培养的人淋巴细胞微核率的影响。

A yellow trivalent metallic element of the rare earth group; occurs in monazite and bastnasite in association with cerium and lanthanum and praseodymium .

一种稀土属黄色多价元素，与铈、镧、镨共生于独居石和氟碳锑矿中。

Ago a kind of misconception that the rare earth metals is very scarce in nature, in fact not the case, many of which elements such as lanthanum, cerium, praseodymium, neodymium and samarium in accordance with their distribution in nature is no less well-known people in some of the elements of industry, common There ore monazite, scandium yttrium stone, silicon and cerium stone, stone and brown curtains and other fluorocarbon calcium cerium ore.

以前有种错误概念，认为稀土金属在自然界很稀少，其实不然，其中很多元素如镧、铈、镨、钕和钐按其在自然界的分布不次于人们在工业上熟知的某些元素，常见的矿石有独居石、钪钇石、硅铈石、褐帘石和氟碳钙铈矿等。

PR2-PR3 Links. All links should be permanent and one way with unique IP address.

PR2的，镨链接。所有的链接应该是永久性的和一个独特的IP地址的方式。

This method could also be applied to prepare praseodymium oxides, however, it was not successful in preparing other light rare earth oxides.

这种方法可以应用到制备氧化镨，但是，无法成功应用到制备其他轻稀土氧化物。

It suggests that rare-earth elements yttrium and praseodymium have certain genotoxicity.

提示稀土元素钇和镨具有一定的遗传毒性。

The effect of DNA damage in human lymphocytes induced by yttrium chloride and praseodymium chloride was detected using SCG assay.

用单细胞凝胶电泳法检测了稀土化合物氯化钇和氯化镨对人外周血淋巴细胞的DNA损伤效应。

A mixture of praseodymium with neodymium is used to make specialty goggles for welders and glass blowers.

选用廉价的镨钕金属代替纯钕金属制造永磁材料，其抗氧性能和机械性能明显提高，可加工成各种形状的磁体。

Within 3 months, four groups in China had replaced the lanthanum with elements such as praseodymium and samarium and driven the temperature for resistance-free flow up to 55 kelvin.

3个月内，中国的4个研究组在用诸如镨和钐等元素取代了镧元素后将无电阻电流运送温度提高至55开。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。