Original title: What is the CE certification process for N95 mask exported to the EU? Can the KN-type mask with exhalation valve in line with GB2626 be used? Because doctors and patients wearing masks can not guarantee that they are healthy and virus-free (infectious during the incubation...

Original title: The strongest rotary drilling arrangement in history, if you don't know, the construction will be in vain! This article has sorted out the characteristics and scope of application of all rotary drilling tools. You can select and use these drilling tools according to their...

Original title: Structural Analysis of Masks Structure Analysis of Masks Basic structural analysis 01 Layers of ordinary masks Cut open a used medical mask, and you will find that the mask has three layers, the (inner) absorbent layer, the (middle) core filter layer, and the (outer) waterproof...

In this life, how many sincere words are expressed in the way of jokes? Some words are true, but they are always taken as jokes. Some of it is a joke, but we all know it's true. Later, whenever I was free, I would go back to visit yuan's mother. It didn't take too long for her to resist me at...

Because it is not clear what is the relationship between Xiao Yan and the ancient clan, so the Venerable Glacier does not want to kill it personally, so as not to cause some unnecessary trouble, but the soul temple and the demon phoenix clan are famous forces in Zhongzhou, their respective...

They were all shouting Shrek's name and the five words Shrek Seven. Yes, even the audience who don't know much about the Soul Master has seen the strength of Shrek Academy and the weakness of their overall strength through this game. However, because of this, Shrek Academy is more respected by...

The spirit of Nirvana is powerful and wonderful, but it is not easy to accept it easily. Even some strong people with half-step Nirvana have to be careful when they absorb the spirit of Nirvana, because once they absorb too much, they are likely to destroy their bodies directly and violently...

Original title: Medical surgical mask, N95, KN95 mask, 3m mask, a little dizzy What is a medical surgical mask? What are N95 and KN95 masks? What is a 3m mask? I can't tell the difference clearly. The surgical mask is a mask worn by medical staff at work, mainly used in medical outpatient...

Original title: Automatic binding machine punching alarm processing method Automatic binding machine punching alarm is an early warning mechanism of automatic binding machine. Xiaobian has collected many questions about automatic binding machine punching alarm to answer them. Of course, if you...

Original title: The strongest rotary drilling arrangement in history, if you don't know, the construction will be in vain! This article has sorted out the characteristics and scope of application of all rotary drilling tools. You can select and use these drilling tools according to their...

Original title: Origin of the "Five-storey Building" Prospecting Model The author searched many network and geological business books, watched the team annals of a unit, interviewed many geological predecessors, and found that they had a high evaluation of the "five-storey" model and the...

Original Title: New Progress in Key Technologies for Underground Metal Mining Underground metal mine mining is a systematic project, including development, development and mining (as shown in Figure 1, underground mine mining model), each link requires blasting. Therefore, how to blast safely...