Classification of rare earths 1) Light rare earth (also known as 铈 group): 镧 , 铈, 镨 , é’• , é’·, é’ , é“• , é’† . 2) Heavy rare earth (also known as é’‡ group): 铽 , é• , é’¬ , é“’ , é“¥ , 镱 , é•¥ , é’ª , é’‡. The difference between the 铈 group and the é’‡ group is because the rare earth mixture obtained by separation of minerals is often named after the ratio of lanthanum or cerium. Rare earth metals (rare earth metals), also known as a rare earth element, is a general term for a group â…¢B periodic table scandium, yttrium, lanthanides 17 elements, commonly represented by R or RE. Their names and chemical symbols are é’ª (Sc), é’‡ (Y), 镧 (La), 铈 (Ce), 镨 (Pr), é’• (Nd), é’· (Pm), é’ (Sm), é“• (Eu ), Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. Their atomic numbers are 21 (Sc), 39 (Y), 57 (La) to 71 (Lu). The element "La" "镧" was named in 1839, when a Swede named "Moussand" discovered that the earth contained other elements. He borrowed the word "hidden" in Greek to use this element. Named "镧". The application of germanium is very extensive, such as piezoelectric materials, electrothermal materials, thermoelectric materials, magnetoresistive materials, luminescent materials (blue powder), hydrogen storage materials, optical glass, laser materials, various alloy materials, and the like. It is also used in the preparation of many organic chemical products. The light-transfer agricultural film is also used in the field. In foreign countries, scientists have given the role of cockroaches to crops as the name of “super calciumâ€. The knife Gate Valve employs straight through structure of flange type or wafer type. It is metal-to-metal sealed or soft-sealed. When being opened or closed, the valve has small friction, so, a long service life, because the wedge and the sealing surface apply unique design, which has no concave cavity retaining water. The stem applies rising-stem type, which has left hand screw. When the stem nut is rotated, the opening scale of the valve can be directly viewed. Knife Gate Valve,Ductile Iron Knife Gate Valve,Ductile Iron Knife Valve,Iron Knife Gate Valve SUZHOU YUEDA VALVE CO., LTD. , https://www.jsyuedavalve.com
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