磁石の基礎知識
The ancient Greeks and Chinese discovered a naturally magnetized stone in nature and called it "magnetite". The stone can magically pick up small pieces of iron and always point in the same direction when swung at will. Early navigators used this magnet as their earliest compass to identify directions at sea. After thousands of years of development, today magnets have become a powerful material in our lives. By synthesizing alloys of different materials, the same effect as magnetite can be achieved, but the magnetic force can also be improved. Man-made magnets appeared in the 18th century, but the process of making stronger magnetic materials was slow until Alnico was made in the 1920s. Subsequently, ferrite (Ferrite) was produced in the 1950s, and rare earth magnets were produced in the 1970s Rare Earth magnets include neodymium iron boron (NdFeB) and samarium cobalt (SmCo). So far, magnetic technology has developed rapidly, and strong magnetic materials have also made components more miniaturized.
磁化（配向）方向は何ですか？
Most magnetic materials can be magnetized to saturation in the same direction, which is called the "magnetization direction" (orientation direction). Magnets without orientation (also called isotropic magnets) are much weaker than oriented magnets (also called anisotropic magnets).
What is the standard industrial definition of "North and South Poles"?
The definition of "North Pole" is that after the magnet rotates at will, its north pole points to the earth's north pole. Likewise, the south pole of the magnet points to the south pole of the earth. How can I tell the north pole of a magnet without a label?
Obviously, it is impossible to tell with the eyes alone. The magnet can be approached with a compass, and a pointer pointing to the Earth's north pole will point to the magnet's south pole.
磁石を安全に取り扱い、保管する方法は？
磁石はそれ自体でくっつき、指をはさむ可能性があるため、常に十分に注意してください。 また、磁石同士が引き寄せられると、衝突により磁石自体が破損する可能性があります（角をノックアウトしたり、クラックをノックアウトしたり）。 フロッピーディスク、クレジットカード、コンピューターモニター、時計、携帯電話、医療機器など、磁化されやすいものから磁石を遠ざけてください。磁石はペースメーカーから遠ざける必要があります。
より大きなサイズの磁石の場合、磁石を簡単に分離できるように、各部品の間にプラスチックまたはボール紙のスペーサーを追加する必要があります。 磁石は、可能な限り乾燥した一定温度の環境で保管する必要があります。
磁気絶縁を実現する方法は？
磁石に吸着できる材料だけが磁場を遮断する役割を果たすことができ、材料が厚いほど、磁場を分離する効果が高くなります。 最強の磁石は何ですか？
現在、最高性能の磁石は希土類磁石であり、希土類磁石の中でNdFeBが最強の磁石です。 しかし、摂氏200度を超える温度では、サマリウムコバルトが最も強力な磁石です。
