Soldering other precipitation may wash the lead into the groundwater. Unfortunately, most lead-free solders are not eutectic formulations, melting at around , making it more difficult to create reliable joints with them. Other common solders include low-temperature formulations (often containing bismuth), which are often used to join previously-soldered assemblies without unsoldering earlier connections, and high-temperature formulations (usually containing silver) which are used for high-temperature operation or for first assembly of items which must not become unsoldered during subsequent operations. Alloying silver with other metals changes the melting point, adhesion and wetting characteristics, and tensile strength. Of all the brazing alloys, silver
Hard and soft C spelling, as shown in the title of one of his books, "Đường kách mệnh". 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