Ștefan Procopiu

Ștefan Procopiu on a postage stamp from the Romanian Post

Ștefan Procopiu ( rum. [ Ʃteˈfan prokoˈpi.u ]) (born January 19, 1890 in Bârlad , Romania , † August 22, 1972 in Iași ) was a Romanian physicist .

Life

Procopiu was born in Bârlad in 1890 . His father Emanoil Procopiu was an employee of the Bârlad City Court. His mother Ecaterina Taşcă was the daughter of Gheorghe I. Taşcă . He attended the Gheorghe Roşca Codreanu grammar school in Bârlad from 1901 to 1908 and studied physics and chemistry at the Alexandru Ioan Cuza University of Iaşi from 1908 to 1912 . After graduating, he worked as an assistant to Professor Dragomir Hurmuzescu .

In 1919, after receiving a scholarship, he continued his studies in Paris , where he attended courses from famous scientists such as Gabriel Lippmann , Marie Curie , Paul Langevin and Aimé Cotton . On March 5, 1924, Procopiu received his doctorate . The topic of his doctoral thesis was "On electrical birefringence in suspensions " ( French original title Sur la biréfringence électrique des suspensions ), which he submitted to an examination board, which also included Aimé Cotton as coordinator and Charles Fabry and Henri Mouton as second examiners.

On January 15, 1925, he returned to Romania and succeeded his former professor Dragomir Hurmuzescu as head of the department with research focuses on gravitation , heat and electricity at the University of Iași. At the same time he took a professorship at the "Gheorghe Asachi" Polytechnic Institute in Iași . During this time, Ștefan Procopiu published his treatise on " Electricity and Magnetism " (1939), followed by his monograph on thermodynamics (1948). Procopiu was a department head until he retired in 1962.

In June 1948 he was appointed the corresponding academician of the Romanian Academy , whose full membership he obtained on July 2, 1955. In 1964 he was awarded the Romanian State Prize. Other awards he received were the Order of Labor ( Ordinul Muncii ), the Star of Romania and the Order of Merit for Science . Procopiu was also twice a member of the Nobel Prize Committee .

In addition to his academic work, Ștefan Procopiu was also an active member of the board of directors of the Iași National Theater.

Ștefan Procopiu died on August 22, 1972 in Iași , Romania , at the age of 82.

Scientific activity

His entry into research took place before he graduated. He continued his research as an assistant professor.

To the magnetic moment of the electron

His first important publication is "to determine the molecular magnetic moment according to M. Planck's quantum theory" ( Determining the Molecular Magnetic Moment by M. Planck's Quantum Theory ). Based on the quantum theory of Max Planck and the theory of magnetism by Langevin, the physical constant of the magnetic moment of the electron is determined, which is called Bohr's magneton . Independently of Procopiu, the Danish physicist Niels Bohr reached the same size two years later , which was subsequently named after him. In honor of Procopiu, the term Bohr – Procopiu Magneton is used in some circles today for the magnetic moment of the electron.

After further research, he developed an experimental method for measuring the magneton in 1954, which he improved in 1964.

Research before and during the First World War

Ștefan Procopiu also researched in the field of wireless communication and in 1913 published a publication " Experimental Research on Wireless Telegraphy ". His inventions also include an apparatus for locating metal projectiles in the bodies of wounded soldiers.

Longitudinal depolarization of light

In 1921, in the physics laboratory of the Sorbonne University , Procopiu investigated the optical phenomenon of the longitudinal depolarization of light in suspensions and colloids. The phenomenon was described in 1930 as the "Procopiu phenomenon" by Prof. Augustin Boutaric . Some of these findings were published in Procopius' doctoral thesis.

Electromotive force on galvanic elements

In 1930 Procopiu dealt with the Barkhausen effect and discovered the circular effect of magnetic discontinuity, which in 1951 was named "Procopiu effect". This discovery had important applications in the development of memory components for computers .

Investigation of the earth's magnetic field

The earth's magnetic field was of great interest to Procopiu. For 25 years he researched around this phenomenon in Romania and produced the country's first magnetic maps. An important finding was the discovery of a magnetic anomaly on the line Iași - Botoșani , as well as the discovery of periodicities in the temporal variation of the earth's magnetic field.

Publications

• Library of Congress

Individual evidence

1. ↑ George-Felix Taşcă - Din descendenţa marelui căpitan Constantin Balaban (1780–1845) - Institutul de Istorie și Arheologie AD Xenopol Iași - Al IV-lea simpozion de studii genealogice 13-15 May 1993.
2. ↑ ^{a b} Personalităţi bârlădene ( Memento from February 19, 2012 in the Internet Archive ) (Sons and Daughters of the City of Bârlad ; PDF; 1.0 MB).
3. ↑ Short biography of Ștefan Procopiu on the homepage of the Alexandru Ioan Cuza University of Iași .
4. ↑ ^{a b c d} Mihai Olteneanu Stefan I. Procopiu 1890 - 1972 (article in the 17th edition / 2005 of the magazine "Univers Ingineresc") .
5. ↑ ^{a b c d} Ștefan Procopiu (1890–1972) biography (Romanian) .
6. ↑ Ștefan Procopiu - Détermination du moment magnétique moléculaire par la théorie des quanta de M. Planck. - Bulletin de la Section Scientifique de l'Académie Roumaine, No.3, 10 Feb. 1913 Bucharest, pp.151-157
7. ↑ ^{a b} Procopiu Stefan (1890–1972) biography (English) .
8. ↑ ^{a b} Stefan Procopiu biography (Romanian) ( memento from October 30, 2007 in the Internet Archive ).
9. ^ Stefan Procopiu. The longitudinal depolarization of light through crystalline liquids and through the soft crystals as a function of temperature . (Kolloid-Zeitschrift. November 1944, Vol. 109, Iss. 2, pp. 90-95) doi: 10.1007 / BF01531695 .
10. ↑ Article in the 5th edition / 2011 of the magazine "Univers Ingineresc" about the Procopiu effect .