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Access control is really a system enabling authorities to manage usage of areas and resources in a very given physical facility or computer-based information system. Access control is, in reality, perhaps the most common, everyday phenomenon. For example, a lock over a car door is basically a sort of access control. The PIN with a bank's ATM method is another way of access control. Even nightclub bouncers, waiting in front of the door, are another instance of (perhaps) a more primitive mode of access control. Using an access control mechanism is important when persons seek to secure confidential, important, or sensitive information and equipment.
However, science and technology are two different social cultures, and the differences between them are obvious. The basic task of science is to know the world and find it, thus increasing the intellectual wealth of mankind. The basic task of technology is to discover the world and invent it to create the material wealth of mankind and enrich the spiritual and cultural life of human society. Science answers questions about "what" and "why"; The technology answers the question "what to do" and "how to do". Therefore, the results of science and technology are different in form. Scientific achievements are generally expressed as concepts, laws, papers and other forms. The technical results are usually in the form of process flow, design drawing, operation method and so on. Scientific products are generally not commercial and technological achievements can be commoditized. Modern technology has a strong utilitarian and commercial color.
Reverse flushing can be done automatically: the backwash is done by hydraulic valve opening and hydraulic cylinder pistons, which are controlled by the backwash controller. The anti-flushing controller can accurately control the hydraulic valve and hydraulic cylinder according to the differential pressure value from the filter inlet and outlet, and the power of the controller comes from the pressure of the line itself.
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