Kammerling Onnes

H. Kammerling Onnes (Nobel Prize for Physics, 1913) discovered superconductivity in Leiden in 1911 when he cooled mercury to the temperature of liquid helium. Many other materials, mostly metals and alloys, were subsequently found to display superconductivity at very low temperatures. 

Various equations of state. Or, Kammerling Onnes equation. (Meerut 1989)... 

IV] Kammerling Onnes equation or virial equation Kammerling Onnes gave an empirical equation which gives the product PV as power series of the pressure at any given temperature. The equation is represented as ... 

The conductivity of some metals changes abruptly near liquid helium temperatures (frequently below 10 K), as in Figure 7.20, and they become superconductors, an effect discovered by Kammerling Onnes in 1911 while studying mercury at liquid helium temperature. In this state, these metals offer no resistance to the flow of electrons, and currents started in a loop will continue to flow indefinitely—several decades at least— without significant change. The elements lead, niobium, and tin are other metals that... 

H. Kammerling Onnes, Expression of the equation of state of gases and liquids by means of series, Commun. Phys. Lab. Univ. Leiden, 71, 1901. 

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