Abstract: Silica crucibles containing an inner layer which is substantially pure and substantially bubble-free and methods for making such crucibles. The inner layer is also substantially stable against roughening and spot devitrification. The inner layer is formed by making a web structure which is then converted to a continuous layer, thereby minimizing or eliminating bubble formation. The inner layer is also formed using a gettering agent which getters alkaline and alkaline-earth elements while the inner layer is formed. The alkaline and alkaline-earth elements are gettered on an innermost portion of the inner layer which is later removed, leaving an inner layer with relatively few impurities. When used in a CZ-crystal growing process, the inner surface of the crucible remains smooth and substantially no bubbles grow in the inner layer.

Abstract: A crucible adapted for use in formation of a silicon crystal comprises a crucible wall including a bottom wall and a side wall. An inner layer is formed on an inner portion of the crucible wall and has distributed therein a crystallization agent containing an element selected from the group consisting of barium, aluminum, titanium and strontium.

Abstract: Silica crucibles containing an inner layer which is substantially pure and substantially bubble-free and methods for making such crucibles. The inner layer is also substantially stable against roughening and spot devitrification. The inner layer is formed by making a web structure which is then converted to a continuous layer, thereby minimizing or eliminating bubble formation. The inner layer is also formed using a gettering agent which getters alkaline and alkaline-earth elements while the inner layer is formed. The alkaline and alkaline-earth elements are gettered on an innermost portion of the inner layer which is later removed, leaving an inner layer with relatively few impurities. When used in a CZ-crystal growing process, the inner surface of the crucible remains smooth and substantially no bubbles grow in the inner layer.

Abstract: A system is disclosed for processing billing records in a data packet transmission network by optimizing the search algorithm for accessing customer records. Using hashing techniques, the hashing parameters of hashing key and modulus base of the modulo arithmetic are varied to optimize the hashing function for recently received billing records. These optimum parameters are then used predictively to hash the next batch of billing records. In a preferred embodiment, the billing records are queued in two ping-pong memories and the contents of one are used to drive the optimizer while the contents of the other are used to drive the billing procedure.

Abstract: Noise reduction of a signal such as a video signal is effected by averaging a plurality of relatively delayed replica signals, e.g. with line or field delays therebetween, in a decoding processor, the highly redundant information content of the signal being reinforced by the averaging while random noise undergoes a partial cancellation. In order to overcome the problem of signal changes caused by the decoding processor, the signal is encoded prior to application to the noise-introducing signal channel by a complementary encoding processor in which one or more replica signals are subtractively combined with one or more other replica signals. In both processors a variable combining means is employed to exclude from the combination replica signals which have a non-small difference from the replica signals in the combination, thereby to avoid smearing of the information content (with consequent picture smearing in the case of a video signal) when the signal is changing, e.g. because of movement in a picture.

Abstract: The invention concerns a dynamic range compressor type encoder or expander type decoder, in which a main signal component in a main path is boosted or bucked by a further signal component derived from a point in the main path by a further path having the characteristics of so restricting the further signal component that the boosting or bucking action is only appreciable below a low level threshold. In the present invention the further signal component is a difference signal formed between a direct signal derived from a point in the main path and a delayed version of either the same signal or of another signal derived from another point in the main path. At the frequency equal to the reciprocal of the delay, and at harmonics of this frequency, the direct and delayed signals cancel. The compressor or expander action, and hence noise reduction action, takes place only at intervening frequencies.