Abstract: A bypass circuit for a rechargeable battery cell has first and second normally open switches in parallel across the cell. The first switch, which can be a backward-biased rectifier, shunts the discharge current between the cell terminals if the battery cell fails but reopens if the battery cell recovers. The second switch shunts the charging current between the cell terminals if the battery cell fails but reopens if the cell recovers. The second switch can be a normally open FET transistor biased to close only when the cell voltage V.sub.C substantially exceeds a normal peak charging voltage V.sub.P. A rechargeable battery system in which the cells are series connected can incorporate a separate bypass circuit across each cell to enable the remaining good cells to continue charging and discharging even if a particular cell fails.

Abstract: Low temperature photonitride (LTPN) films of excellent quality have been prepared at temperatures ranging from 300.degree. C. downward to 100.degree. C. by a photochemical vapor deposition process, wherein a mixture of silane, ammonia, and hydrazine is caused to react to form Si.sub.3 N.sub.4 films at the substrate interface. These films are suitable for the preparation of silicon nitride passivation layers on solid-state devices, such as metal-oxide semiconductors (MOS) and charge coupled devices to impart enhanced reliability.

Abstract: A disposable ventilation study system for dispensing a single-patient dosage of gaseous radioisotopes to patients for pulmonary function studies is disclosed. A gas impermeable capsule encloses the gaseous radioisotope and is stored within a radioactivity shielding body of valve means which shears the capsule to dispense the radioisotope to the patient. A breathing bag receives the patient's exhalation of the radioisotope and permits rebreathing of the radioisotope by the patient.