A network appliance for monitoring, diagnosing and documenting problems among a plurality of devices and processes coupled to a computer network utilizes periodic polling and collection of object-generated trap data to monitor the status of objects on the computer network. A proofing process includes obtaining sample document images from the output document images, and for each obtained sample document image, performing a review procedure. The method for producing high-purity lanthanum, in which total content of gas components is 1000 wtppm or less. The collapsible net assembly includes a pair of curvilinear net rims threaded through a hook free net. To accomplish the object, a deformation zone, which can be brought into contact with a support surface by the admission pressure by admitting pressure in the direction of a reduction of the active area of the compensating diaphragm, is provided in the area of a compensating diaphragm.