The present invention describes processes for the preparation of a lipid blend and a uniform filterable phospholipid suspension containing the lipid blend, such suspension being useful as an ultrasound contrast agent. The regulation loop is de-signed in such a way as to determine whether, for the actual value of said uncontrollable quantity, the actual value of the controlled quantity is greater or lower than the optimal value and to generate a regulation signal to modify the actual value of the controlled quantity towards the optimal value. A method and system for networking users of a GIS data management system is also provided. The hook mechanism includes an arm base, and an end of the arm base is connected to a surface of the accommodating space.