Deep Groove ball bearings are the most popular of all the ball bearing types because they are available in a wide variety of seal, shield and snap-ring arrangements.

深沟球轴承是所有类型的球轴承最流行的，因为他们是在一个密封，盾牌和管理各种各样的戒指安排可用。

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There are two types of seals. Static seal and dynamic seal.

密封垫的种类有两种。静密封和动密封。

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Seal performance tests and operation life simulation of various types of reciprocating seals can be done on this device.

可用于多种规格型式的运动密封，进行密封性能和使用寿命实际模拟试验。

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The Ministry of Education issued a decree establishing an official seal of approval and two types of certificate to be awarded to states and municipalities who succeed in providing good and effective basic education, including youth and adult literacy programmes.

UNESCO: Country Profile: Brazil