稀土

The method comprises steps: dissloving relative rare earth oxidant into nitrate to prepare rare- earth azotic acid solution, adding solid nitrate, boracic acid, citrate and urea according to proportion, mixing, calcinating with burning method and getting final product.

制备时，将相应的稀土氧化物溶于硝酸，配成稀土硝酸盐溶液，按计量比加入固体硝酸、硼酸、及柠檬酸与尿素，混合均匀，利用燃烧法灼烧，即得产品。

This invention discloses a new technology for preparing rear earth ionic doped fiber prefabricated rods with DC-RTA technology in a sol-gel method including preparing sol containing necessary doped ions, coating said sol uniformly on the inner wall of the quartz glass tube and burning it under high temperature to coagulate and vitrify them to a doped layer and repeating the above process to form a fiber prefabricated rod by oxygen and hydrogen flame after the doped layer reaches to a designed thickness and the fiber prefabricated rod can be made to various rare earth ionic doped fibers by an ordinary drawbench technology.

本发明属于光纤制造和光纤激光技术领域，具体公开了一种利用溶胶凝胶方法中的DC-RTA技术制备稀土离子掺杂光纤预制棒的新工艺。该工艺步骤包括预先配制好含有所需掺杂离子的溶胶，将该溶胶均匀涂覆在石英玻璃管的内壁后高温灼烧，使之凝结并玻璃化为一层掺杂层。反复上述涂覆灼烧过程，在掺杂层达到设计厚度后由氢氧焰高温收棒形成光纤预制棒。该方法所得到的光纤预制棒可以通过普通拉丝工艺拉制成各类稀土离子掺杂光纤。

The results demonstrated that 81%-89% of LREEs in 1eaves were associated with cell wall.

通过对这些组分稀土分布的测定，叶片中81%-89%的轻稀土分布在细胞壁上。

The preparation process includes the following steps: dissolving activator and RE oxide in the molar ratio of 0.01-0.02 in concentrated nitric acid and heating to dry, dissolving the obtain RE nitrate in deionized water to obtain solution of RE nitrate; dissolving soluble tungstate and surfactant in deionized water to obtain tungstate solution; mixing the RE nitrate solution and the tungstate solution through stirring to reaction for 25-60 min to obtain white precipitate; hydrothermal reaction of the precipitate in a reaction kettle at 100-260 deg.c for 24-72 hr; centrifugally separating, washing and drying to obtain the product.

浓硝酸的加入量保证稀土氧化物溶解就可以，过量的硝酸可以加热除去；将可溶性钨酸盐和表面活性剂溶解于去离子水中，得到钨酸盐溶液，表面活剂性的加入量为反应原料重量的0-30wt％；将稀土硝酸盐溶液加入到钨酸盐溶液中搅拌，发生沉淀反应，磁力搅拌时间为25-60分钟，得到白色沉淀；将含有沉淀物的溶液作为前驱物加入到反应釜中，发生水热反应，反应温度为100-260℃，反应时间为24～72小时；离心分离，洗涤，干燥，即得所需产物。

The results indicated that the effect of lanthanum was better than ceria in the process of synthesize SiC by carbonthermal reduction method.

表明在碳热还原法制备SiC粉体的过程中，稀土镧的作用要强于稀土铈。

Of Rare Earth of China is in Baotou , which containing 50% cerium oxide, and most of them are products as raw materials, resulting in a serious backlog.

中国的稀土80％在包头，包头稀土矿中含50％氧化铈，基本都是原料型产品，因而出现严重积压。

"In September 2008 around 99.9 percent purity cerium oxide is 18 yuan / kg, while the highest sold over the past 30 yuan / kg," said董森"high-tech electronics, laser, communications, superconducting materials, such as the need for Rare Earth, but China's rare-earth prices has not gone up, not their own pricing, it is a disadvantage."

"在2008年9月前后，纯度为99.9％的氧化铈为18元/公斤，而过去最高卖到30元/公斤，"董森华说，"高科技电子、激光、通讯、超导等材料都需要稀土，但中国的稀土价格并没有水涨船高，无法自己定价，很吃亏。"

This dissertation divides into seven chapters and the main contents and conclusions are listed as following:1. Three series binuclear lanthanide carboxylate coordination polymers 1～7 have been synthesized under hydrothermal conditions by altering the length of carbon chains between carboxyl group and phenyl ring on ligands, which are isophthalic acid, 1,3-phenylenediacetic acid and 1,3-phenoxydiacetic acid, and lanthanide ions such as Pr~(3+), Eu~(3+)and Ho~(3+).

论文共分七章，主要研究内容和结论如下：1、通过改变间苯二甲酸配体的羧基和苯环之间的碳链长度，从间苯二甲酸、间苯二乙酸到间苯二氧乙酸，以及改变稀土离子半径Pr~(3+、Eu~(3+)和Ho~(3+)出发，在水热条件下制备了三个系列双核金属单元的稀土羧酸二维配位聚合物1～7。

These characteristics confirmed further that some features of inclusion, especially their types, in a same subgroup of chondrite are similar.

富杆拦石集合体和富黄长石包体的稀土模式大多数为平坦型，富尖晶石包体NQ-32有Ⅱ型的稀土模式，这些特征进一步证实同类球粒陨石的难熔包体特征，尤其是它们的类别是相似的。

Possibility of reducing dephosphorization of the steel with rare earth has been analyzed theoretically.

从理论上分析了稀土对钢液还原脱磷的可能性，并在5kg真空感应电炉内用La-Ce-Pr-Nd混合稀土金属对1Cr18Ni9Ti不锈钢进行了还原脱磷试验。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。