Ultrasound

The invention: 

A medically safe alternative to X-ray examination,
ultrasound uses sound waves to detect fetal problems in pregnant
women.

The people behind the invention:

Ian T. Donald (1910-1987), a British obstetrician

Paul Langévin (1872-1946), a French physicist

Marie Curie (1867-1946) and Pierre Curie (1859-1906), the French husband-and-wife team that researched and developed the field of radioactivity

Alice Stewart, a British researcher

Ultramicroscope

The invention: 

A microscope characterized by high-intensity illumination
for the study of exceptionally small objects, such as colloidal
substances.


The people behind the invention:

Richard Zsigmondy (1865-1929), an Austrian-born German
organic chemist who won the 1925 Nobel Prize in Chemistry
H. F. W. Siedentopf (1872-1940), a German physicist-optician
Max von Smouluchowski (1879-1961), a German organic
chemist.

Ultracentrifuge

The invention: 

Asuper-high-velocity centrifuge designed to separate
colloidal or submicroscopic substances, the ultracentrifuge
was used to measure the molecular weight of proteins and
proved that proteins are large molecules.