Johannes Diderik van der Waals higher temperatures. Nitrogen, oxygen, hydrogen, and helium subsequently succumbed to liquefaction. Heike Kamerlingh Onnes was significantly influenced by the pioneer work of van der Waals. In 1908, Onnes became the first to make liquid helium; this led directly to his 1911 discovery of superconductivity. Van der Waals started his career as a school teacher. He became the first physics professor of the University of Amsterdam when in 1877 the old Athenaeum was upgraded to Municipal University. Van der Waals won the 1910 Nobel Prize in physics for his work on the equation of state for gases and liquids. Johannes Diderik
Heike Erkers of employers performing salary surveys (lönekartläggning) on a regular basis. Another issue is child poverty. She is also a member of the Executive Committee of the European Federation of Public Service Unions (EPSU) Heike Erkers Heike Erkers is the Chair of the Swedish labour union Akademikerförbundet SSR (in English 'The Union for Professionals'). She is currently off duty from her regular employment as a head of department at the Swedish Public Employment Service (in Swedish 'Arbetsförmedlingen'). Heike Erkers started being in enganged in labour union issues in the 1990s. In 2003 she was elected member of the board of Akademikerförbundet