Glass-to-metal seal little lower than that of the soda-lime glass. Classically high lead containing glasses are used, but it is also possible to substitute these by multi-component glasses e.g. based on the system ---------. Glass-to-metal seal Glass-to-metal seals are a very important element of the construction of vacuum tubes, electric discharge tubes, incandescent light bulbs, glass encapsulated semiconductor diodes, reed switches, pressure tight glass windows in metal cases, and metal or ceramic packages of electronic components. Properly done, such a seal is hermetic (vacuum tight, good electrical insulation, special optical properties e.g. UV lamps). To achieve such a seal, two properties must
Hard and soft C Hard and soft C In the Latin-based orthographies of many European languages (including English), a distinction between hard and soft occurs in which represents two distinct phonemes. The sound of a hard (which often precedes the non-front vowels , and ) is that of the voiceless velar stop, (as in "car") while the sound of a soft (typically before , and ), depending on language, may be a fricative or affricate. In English, the sound of soft is (as in "citrus"). There was no soft in classical Latin, where it was always pronounced as . Modern English pronunciation of early