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Most stable nuclides have roughly equal numbers of protons and neutrons, so the line for which Z = N forms a rough initial line defining stable nuclides. The greater the number of protons, the more neutrons are required to stabilize a nuclide; nuclides with larger values for Z require an even larger number of neutrons, N > Z, to be stable. The ...
A push-button telephone is a telephone that has buttons or keys for dialing a telephone number, in contrast to a rotary dial used in earlier telephones.. Western Electric experimented as early as 1941 with methods of using mechanically activated reeds to produce two tones for each of the ten digits and by the late 1940s such technology was field-tested in a No. 5 Crossbar switching system in ...
Virtually all new cordless phones sold in the US use DECT 6.0 on the 1.9 GHz band, though legacy phones can remain in use on the older 900 MHz, 2.4 GHz and 5.8 GHz bands. There is no specific requirement for any particular transmission mode on the older bands, but in practice many legacy phones also have digital features such as DSSS and FHSS .
Other American and foreign telephone manufacturers had already produced this type of telephone, often referred to as French phone. In the Bell System, hand telephones formally replaced the hitherto used deskstand , colloquially called candlestick , by the end of the 1920s, although reconditioned candlestick telephones remained in service for at ...
Iron-55 (55 Fe) is a radioactive isotope of iron with a nucleus containing 26 protons and 29 neutrons. It decays by electron capture to manganese-55 and this process has a half-life of 2.737 years. The emitted X-rays can be used as an X-ray source for various scientific analysis methods, such as X-ray diffraction.
The telephone instrument obtained talking current by powering a carbon microphone with a local battery, consisting of "N° 6" zinc–carbon dry cells. By around 1900, large racks of motor-generator sets in the telephone exchange could supply this ringing current remotely instead and the local magneto was often no longer required, [ 2 ] but ...
D, E, and F blocks covered huge areas of the country, typically several states at a time, and covered 2 × 5 MHz for D and E blocks, 2 × 10 MHz for F. [5] The 700 MHz band was auctioned in early 2008 using spectrum previously used by television stations' analog broadcasts, with Verizon Wireless and AT&T Mobility winning the majority of ...
m n is the mass of neutron. M is the nuclear mass. N is the neutron number. The nuclear mass defect is usually converted into nuclear binding energy, which is the minimum energy required to disassemble the nucleus into its constituent nucleons. This conversion is done with the mass-energy equivalence: E = ∆mc 2. However it must be expressed ...