Abstract: A scannable latch system comprises a plurality of scannable latches and clock driver circuit that allow at-speed testing of integrated circuits. Each scannable latch comprises a master latch, a slave latch and an auxiliary latch. The master latch is a two input latch capable of receiving data from two sources. The output of the master latch is coupled to the input of the slave and auxiliary latches. The clock driver circuitry receives a clock and control signals which are transformed into signals that operate the scannable latch in three different modes. In the normal mode, the slave latch is transparent and the data is held primarily in the master latch. In the scan mode, data may be shifted into the master, shifted out through the auxiliary latch, or shifted both in and out with a propagate function. Finally, in a test mode independent data values may be stored in the master latch and the slave latch.

Abstract: A simple process is provided for making two self-aligned recessed oxide isolation regions of different thicknesses which includes the steps of defining first and second spaced apart regions on the surface of a semiconductor substrate, forming a protective layer over the first region, forming a first insulating layer of a given thickness within the second region while the first region is protected by the protective layer, removing the protective layer from the first region and forming a second insulating layer thinner than that of the first layer within the first region. Field regions may be ion implanted prior to forming the insulating layers.

Abstract: Culturing an alga with known flocculant production capability on the soil for the purposes of aggregating soil particles is disclosed. According to the disclosure, flocculant producing algae are known in liquid culture medium as disclosed in pending application Ser. No. 421,527 filed Dec. 4, 1973. The nitrogen in the culture medium is maintained so that cellular nitrogen does not fall below 10%. The algae are then inoculated onto soil which is provided with supplemental nutrients and moisture sufficient to produce a multiplication on the order of several hundred fold. The nutrients other than nitrogen are provided in sufficient quantity to permit a further period of growth during which algal flocculants are produced which have the property of binding soil particles into workable aggregates.

Abstract: Cultivation of algae to produce long chain polymers having flocculating properties is disclosed. Algae are cultivated in an aqueous nutrient medium until relatively high culture densities are achieved and thereafter under conditions in which the cells become deficient in nitrogen thereby causing the cells to shift from a growth phase in which protein production predominates to a growth phase in which extracellular polymer production predominates. An adequate supply of other nutrients as well as CO.sub.2 and light are maintained in the culture medium during the latter phase to insure that a change in cell metabolism is produced by a deficiency in nitrogen. The algae then produce high molecular weight polymers exhibiting strong flocculating activity.