摘要:
A method and a related circuit structure are described for improving the effectiveness of ESD protection in circuit structures realized in a semiconductor substrate overlaid with an epitaxial layer and including at least one ESD protection lateral bipolar transistor realized in the surface of the epitaxial layer. The method consists of forming under the transistor an isolating well that isolates the transistor from the substrate. Advantageously, the transistor can be fully isolated from the substrate by first and second N wells which extend from the surface of the epitaxial layer down to and in contact with the buried well.
摘要:
Stable aqueous suspensions of zeolite 4A which can be easily pumped, containing from 0.5 to 65% of zeolite and from 0.05 to 6 g (per 100 g of zeolite) of a suspending agent, composed of mixtures of ethoxylated alkanols, said mixtures being obtained by ethoxylating: a) biodegradable branched alkanols, having from 10 to 18 carbon atoms and having a single branching in position 2, said mixtures containing at least 2 alkanols having a different number of C atoms; or b) mixtures containing 40-100% of branched alkanols as in a) and 60-0% of linear alkanols having from 10 to 18 C atoms.
摘要:
Raw gaseous formaldehyde is purified by passing it through a first series of superimposed fluidized beds of solid adsorbent, maintained at 80.degree.-140.degree. C., while continuously circulating solid adsorbent from each bed to the underlying bed and discharging from the lowermost bed the spent adsorbent, delivering the latter to the uppermost bed of a second series of superimposed fluidized beds of solid adsorbent, passing through the latter a stream of inert gas to strip the adsorbed formaldehyde at 130.degree.-150.degree. C., while continuously circulating said spent adsorbent from each bed to the underlying bed and discharging from the lowermost bed the adsorbent thus treated, delivering the latter to the uppermost bed of a third series of fluidized beds of solid adsorbent, and passing through the latter a stream of inert gas to regenerate the adsorbent at 145.degree.-250.degree. C., while continuously circulating the adsorbent from each bed to the underlying bed, discharging the regenerated adsorbent from the lowermost bed and recycling said regenerated adsorbent to the uppermost bed of the first series.
摘要:
Process for the separation of trioxane from aqueous solutions containing it together with formaldehyde, which comprises subjecting the said solutions to evaporation at temperatures of 100.degree. C or lower, at pressures lower than atmospheric, and with residence times of less than 1 minute under the evaporation conditions, with vaporization of a quantity of from about 5 to about 15% by weight of the solution introduced, and recovering the trioxane from the products evaporated in this way.
摘要:
Polyformaldehyde is prepared by feeding anhydrous formaldehyde to a reaction medium containing a liquid organic diluent non-solvent for the polyformaldehyde and non-reactive towards the other constituents of the reaction medium, and containing in a dispersed form a copolymer A-B, whereinA is a polylactonic block of recurring units ##EQU1## B is a polylactamic block of recurring units ##EQU2## wherein PM.sub.1 and PM.sub.2 are linear polymethylene chains having from 2 to 13 and 3 to 13 carbon atoms, respectively.