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Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach, who also discovered praseodymium. Neodymium is present in significant quantities in the minerals monazite and bastnäsite. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Neodymium is ...
In 1934, Willard Libby reported that he had found weak beta activity in pure neodymium, which was attributed to a half-life over 10 12 years. [25] Almost 20 years later, it was claimed that the element occurs in natural neodymium in equilibrium in quantities below 10 −20 grams of promethium per one gram of neodymium. [25]
A neodymium magnet (also known as NdFeB, NIB or Neo magnet) is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd 2 Fe 14 B tetragonal crystalline structure. [1] They are the most widely used type of rare-earth magnet .
Parts-per-million cube of relative abundance by mass of elements in an average adult human body down to 1 ppm. About 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium ...
For this reason, the most common magnet size is a 3×1mm neodymium disk magnet. Usually the magnets used are of the highest strength available, as a stronger magnet leads to higher magnetic field sensitivity. Perhaps the most important consideration is a coating for the magnet, as typical neodymium disk magnets are not suitable for implantation.
Its discovery is generally believed to have originated in India around the 4th century AD, [65] although Singaporean mathematician Lam Lay Yong claims that the method is found in the Chinese text The Nine Chapters on the Mathematical Art, from the 1st century AD. [66] 60 AD: Heron's formula is discovered by Hero of Alexandria. [67]
The discovery of human bone fragments sent the researchers digging through the material excavated about nine decades ago — in which they found additional skeleton fragments.
The oldest known iron objects used by humans are some beads of meteoric iron, made in Egypt in about 4000 BC. The discovery of smelting around 3000 BC led to the start of the Iron Age around 1200 BC [15] and the prominent use of iron for tools and weapons. [16] Recognised as an element by Guyton de Morveau, Lavoisier, Berthollet, and Fourcroy ...